Showing papers in "Apmis in 1998"
TL;DR: The present knowledge of age pigment formation is outlined, possible mechanisms responsible for the increase of lipofuscin with age are considered, and oxidative reactions are considered to act as age‐independent enhancers of lip ofuscin accumulation.
Abstract: Lipofuscin (age pigment) is a brown-yellow, electron-dense, autofluorescent material that accumulates progressively over time in lysosomes of postmitotic cells, such as neurons and cardiac myocytes. The exact mechanisms behind this accumulation are still unclear. This review outlines the present knowledge of age pigment formation, and considers possible mechanisms responsible for the increase of lipofuscin with age. Numerous studies indicate that the formation of lipofuscin is due to the oxidative alteration of macromolecules by oxygen-derived free radicals generated in reactions catalyzed by redox-active iron of low molecular weight. Two principal explanations for the increase of lipofuscin with age have been suggested. The first one is based on the notion that lipofuscin is not totally eliminated (either by degradation or exocytosis) even at young age, and, thus, accumulates in postmitotic cells as a function of time. Since oxidative reactions are obligatory for life, they would act as age-independent enhancers of lipofuscin accumulation, as well as of many other manifestations of senescence. The second explanation is that the increase of lipofuscin is an effect of aging, caused by an age-related enhancement of autophagocytosis, a decline in intralysosomal degradation, and/or a decrease in exocytosis.
349 citations
TL;DR: The characteristics of the predominant clones which are nowadays causing meningococcal disease in the world are summarized here and the importance of population genetics in interpreting the epidemiological data is illustrated.
Abstract: Under non-epidemic conditions, Neisseria meningitidis causes disease primarily in children under the age of 5 and the cases are sporadic without any evident relationship between them. Occasionally, localized outbreaks of meningococcal disease occur, and sometimes epidemic waves of disease may spread to several countries or even continents and constitute a pandemic. In the past 10 years or so, population genetic analyses have provided insights into the biology of the bacterium and the epidemiology of meningococcal disease, improving our understanding of the cause of epidemics. Through the application of molecular methods, and especially multilocus enzyme electrophoresis, to N. meningitidis strains of worldwide origin, it has been possible to identify virulent clones and provide a surveillance system to warn of meningococcal epidemics. The characteristics of the predominant clones which are nowadays causing meningococcal disease in the world are summarized here and the importance of population genetics in interpreting the epidemiological data is illustrated.
268 citations
TL;DR: It is considered the possibility that CIS cells may loose their stem cell potential with ageing, and the Sertoli and Leydig cells, which are activated postnatally and during and after puberty, may play a crucial role for both the development of the CIS gonocyte and progression of the neoplasm to invasiveness.
Abstract: Why is there a small peak of germ cell tumours in the postnatal period and a major peak in young age, starting at puberty? And, paradoxically, small risk in old age, although spermatogenesis is a lifelong process? Why is this type of cancer more common in individuals with maldeveloped gonads, including undescended testis, gonadal dysgenesis and androgen insensitivity syndrome? Why has there, during the past 50 years, been a quite dramatic increase in testicular cancer in many developed countries? These are just a few of many questions concerning testicular cancer. However, the recent progress in research in the early stages of testicular cancer (carcinoma in situ testis (CIS)) allows us to begin to answer some of these questions. There is more and more evidence that the CIS cell is a gonocyte with stem cell potential, which explains why an adult man can develop a non-seminoma, which is a neoplastic caricature of embryonic growth. We consider the possibility that CIS cells may loose their stem cell potential with ageing. Along these lines, a seminoma is regarded a gonocytoma where the single gonocytes have little or no stem cell potential. The Sertoli and Leydig cells, which are activated postnatally and during and after puberty, may play a crucial role for both the development of the CIS gonocyte and progression of the neoplasm to invasiveness. The reported increase in testicular cancer is not the only sign that male reproductive health is at risk. There are reports that undescended testis and hypospadias have become more common. Also semen quality has deteriorated, at least in some countries. The epidemiological evidence suggests that environmental factors may play a role. Are the environmental hormone disrupters (e.g. DDT, PCB, nonylphenol, bisphenol A) to be blamed for the apparently synchronised deterioration in these aspects of male reproductive health?
242 citations
TL;DR: The results show the present level of resistance to growth promoters in bacteria from food animals in Denmark will form the baseline for comparison with future prospective studies, thereby enabling the determination of trends over time.
Abstract: This study was conducted to describe the occurrence of acquired resistance to antimicrobials used for growth promotion among bacteria isolated from swine, cattle and poultry in Denmark. Resistance to structurally related therapeutic agents was also examined. Three categories of bacteria were tested: 1) indicator bacteria (Escherichia coli, Enterococcus faecalis, Enterococcus faecium), 2) zoonotic bacteria (Campylobacter, Salmonella, Yersinia enterocolitica), and 3) animal pathogens (E. coli, Staphylococcus aureus, coagulase-negative staphylococci (CNS), Staphylococcus hyicus, Actinobacillus pleuropneumoniae). All antimicrobials used as growth promoters in Denmark and some structurally related therapeutic agents (in brackets) were included: Avilamycin, avoparcin (vancomycin), bacitracin, carbadox, flavomycin, monensin, olaquindox, salinomycin, spiramycin (erythromycin, lincomycin), tylosin (erythromycin, lincomycin), and virginiamycin (pristinamycin). Bacterial species intrinsically resistant to an antimicrobial were not tested towards that antimicrobial. Breakpoints for growth promoters were established by population distribution of the bacteria tested. A total of 2,372 bacterial isolates collected during October 1995 to September 1996 were included in the study. Acquired resistance to all currently used growth promoting antimicrobials was found. A frequent occurrence of resistance were observed to avilamycin, avoparcin, bacitracin, flavomycin, spiramycin, tylosin and virginiamycin, whereas resistance to carbadox, monensin, olaquindox and salinomycin was less frequent. The occurrence of resistance varied by animal origin and bacterial species. The highest levels of resistance was observed among enterococci, whereas less resistance was observed among zoonotic bacteria and bacteria pathogenic to animals. The association between the occurrence of resistance and the consumption of the antimicrobial is discussed. The results show the present level of resistance to growth promoters in bacteria from food animals in Denmark. They will form the baseline for comparison with future prospective studies, thereby enabling the determination of trends over time.
235 citations
TL;DR: The results of this study show the present level of resistance to antimicrobial agents among a number of bacterial species isolated from food animals in Denmark, enabling the determination of trends over time.
Abstract: This study describes the establishment and first results of a continuous surveillance system of antimicrobial resistance among bacteria isolated from pigs, cattle and broilers in Denmark. The three categories of bacteria tested were: 1) indicator bacteria (Escherichia coli, Enterococcus faecalis, Enterococcus faecium), 2) zoonotic bacteria (Campylobacter coli/jejuni, Salmonella enterica, Yersinia enterocolitica), and 3) animal pathogens (E. coli, Staphylococcus aureus, coagulase-negative staphylococci (CNS), Staphylococcus hyicus, Actinobacillus pleuropneumoniae). A total of 3304 bacterial isolates collected from October 1995 through December 1996 were tested for susceptibility to all major classes of antimicrobial agents used for therapy in Denmark. Bacterial species intrinsically resistant to an antimicrobial were not tested towards that antimicrobial. Acquired resistance to all antimicrobials was found. The occurrence of resistance varied by animal origin and bacterial species. In general, resistance was observed more frequently among isolates from pigs than from cattle and broilers. The association between the occurrence of resistance and the consumption of the antimicrobial is discussed, as is the occurrence of resistance in other countries. The results of this study show the present level of resistance to antimicrobial agents among a number of bacterial species isolated from food animals in Denmark. Thus, the baseline for comparison with future prospective studies has been established, enabling the determination of trends over time.
193 citations
TL;DR: It is speculated that phenotypical heterogeneity of CIS cells may be associated with their potential to give rise to different tumour types, and may be related to the developmental stage of the early germ cell which has undergone malignant transformation.
Abstract: Clinical observations and epidemiological evidence suggest that important aetiopathological events that cause neoplastic transformation of the male germ cell may occur in fetal life or early infancy. The incidence of germ cell neoplasia is high in individuals with various disorders of gonadal development and sexual differentiation, such as gonadal dysgenesis or androgen insensitivity syndrome. Increased risk has also been noted in individuals with trisomy 21, idiopathic infertility and low birth weight. Infertility is sometimes associated with small aberrations of sex chromosomes (e.g. low frequency mosaicism XY/XO) which can also be found in patients with testicular cancer. The variety of conditions that predispose to testicular neoplasia and the rise in its incidence in many countries speaks for the influence of environmental factors which may affect genetically predisposed individuals. We hypothesise that if the development of the testis is disturbed or delayed, primordial germ cells or gonocytes undergo maturation delay or differentiation arrest which may render them susceptible to neoplastic transformation. Morphologically homogenous premalignant carcinoma in situ (CIS) cells have the potential to differentiate into a variety of histological forms of overt testicular tumours. Analysis of cell surface antigens expressed by CIS cells found in the vicinity of pure and mixed tumours demonstrates that CIS cells are phenotypically heterogeneous. Comparison of the phenotypes of CIS cells, primordial germ cells, human embryonal carcinoma cells and closely related primate embryonal stem cells reveals various similarities but also differences. We speculate that phenotypical heterogeneity of CIS cells may be associated with their potential to give rise to different tumour types, and may be related to the developmental stage of the early germ cell which has undergone malignant transformation.
158 citations
TL;DR: In this paper, the authors identify a new member of the wnt family, which is activated following retinoic acid induction of differentiation but is later downregulated as the cells mature into neurones and other cell types.
Abstract: The histogenesis of germ cell tumours (GCT) reflects the normal processes of gametogenesis, fertilisation and subsequent embryonic cell differentiation. Understanding the mechanisms that control the differentiation of embryonal carcinoma (EC) cells into a variety of embryonic and extraembryonic cell types is pertinent to understanding the progression of GCT. EC cells also provide a tool for analysing the mechanisms that control differentiation during embryonic development, and particularly the mechanisms that control differentiation along alternative cell line, NTERA2, into neurones and other cell types in response to agents such as retinoic acid, HMBA and the bone morphogenetic proteins. We have also compared the pluripotent NTERA2 EC cells with other human EC cell lines that exhibit a much reduced capacity for cell differentiation. A variety of genes are activated during NTERA2 differentiation. In particular we have identified a novel human member of the wnt family. This wnt gene is activated following retinoic acid induction of differentiation but is later down-regulated as the cells mature into neurones and other cell types. We have also observed expression of genes belonging to the Frizzled family, which is likely to include genes encoding receptors for the wnt gene products. Thus in the NTERA2 system, genes pertinent to regulating cell differentiation during embryonic development are activated and appear to play a role in modulating how these pluripotent human EC cells differentiate.
135 citations
TL;DR: It is proposed as a hypothesis that there may exist common aetiological factors for testicular cancer, low fertility and low offspring sex-ratio, and that a search for the causal factors involved may focus on agents that can act prenatally to disrupt the normal development and differentiation of the male reproductive organs.
Abstract: In the last few decades, the male proportion of newborn babies has been decreasing in several populations. The changes are very small and without practical importance per se, but the underlying biological mechanisms are not known. In the same period, testicular cancer incidence has increased, and there has been indications of decreasing sperm counts in men in several populations. The available knowledge on factors that influence the sex-ratio in humans supports the idea that an excess of girls in the offspring of a man may be an indicator of reproductive hazards. Data from a Danish case-control study show strong associations between testicular cancer, low fertility and a low M:F sex-ratio in the offspring. It is proposed as a hypothesis that there may exist common aetiological factors for testicular cancer, low fertility and low offspring sex-ratio, and that a search for the causal factors involved may focus on agents that can act prenatally to disrupt the normal development and differentiation of the male reproductive organs.
134 citations
TL;DR: It is hypothesize that modifications decreasing the stability of these proteins might be a means of improving the immune response to these potentially therapeutically useful antigens, and that such highly organized stable structures could reduce denaturation of the protein and, thus, ubiquitinylation as a degradation signal, and diminish the efficiency of theprotein unfolding.
Abstract: During the last 7 years significant progress has been made in the identification of melanoma-associated antigens recognized by cytotoxic T lymphocytes (CTL). These antigens belong to three main groups: cancer/testis-specific antigens (MAGE, BAGE, GAGE, PRAME and NY-ESO-1), melanocyte differentiation antigens (tyrosinase, Melan-A/MART-1, gp100, TRP-1 and TRP-2), and mutated or aberrantly expressed antigens (MUM-1, CDK4, beta-catenin, gp100-in4, p15 and N-acetylglucosaminyltransferase V). In this review we have summarized the available data concerning the characterization of melanoma-associated antigens, focusing on their immunogenic and protective properties. The development of a strong immune response to differentiation antigens is limited by the existence of tolerance to these "self"-antigens, permitting the involvement of only T cells with low affinity T-cell receptors. Among the melanoma differentiation antigens, only gp100 has been shown to be a tumor regression antigen. The cancer/testis-specific antigens such as MAGE and PRAME should potentially be highly immunogenic antigens. They contain several potential HLA class I binding epitopes and are present only in the testes, which are not accessible to the cells of the immune system owing to the lack of direct contact with the immune cells and the lack of HLA class I expression on the surface of germ cells. But only two patients have been found who responded to these antigens in vivo, indicating their genuinely low immunogenicity. A comparison of the predicted secondary structures of these two groups of antigens (cancer/testis-specific and differentiation antigens) revealed enrichment of long alpha-helical stretches in the cancer/testis-specific antigens. We hypothesize that such highly organized stable structures could, first, reduce denaturation of the protein and, thus, ubiquitinylation as a degradation signal, and, second, diminish the efficiency of the protein unfolding - a necessary step in the proteolytic cleavage by proteasomes. High structural stability could therefore be responsible for the low immunogenicity of these proteins. In this case, modifications decreasing the stability of these proteins might be a means of improving the immune response to these potentially therapeutically useful antigens.
104 citations
TL;DR: To analyse the frequency of autopsy‐proven venous thromboembolism within a defined region and evaluate if certain risk groups not earlier recognized could be found, the incidence of objectively diagnosed venous blood clotting disorders was calculated.
Abstract: OBJECTIVE: To analyse the frequency of autopsy-proven venous thromboembolism within a defined region and evaluate if certain risk groups not earlier recognized could be found. The incidence of objectively diagnosed venous thromboembolism was also calculated. SETTING: The city of Malmo, Sweden, with 230,000 inhabitants. MAIN OUTCOME MEASURE: Analysis of 2,356 autopsies for the year 1987 of deceased inhabitants from the city of Malmo (2,981 deceased, autopsy frequency 79.0%) regarding venous thromboembolism. RESULTS: 25% of autopsies revealed venous thromboembolism. At the acute-care hospital 31%, at the chronic hospital 37%, but in forensic autopsies of non-hospital deaths only 5% (p<0.001) revealed venous thromboembolism. Major pulmonary embolism was seen in 13% and was more frequent in in-hospital deaths (p<0.001). Two in-hospital and two non-hospital deaths due to pulmonary embolism and fractures were found: two patients with knee fractures, one hip fracture and one ankle fracture patient. The incidence of objectively diagnosed venous thromboembolism (autopsy, phlebography, perfusion scintigraphy) was calculated and an incidence of 42.5/10,000 inhabitants/year was found, (strongly age-dependent). CONCLUSION: Venous thromboembolism is a common finding in autopsies of hospitalized patients. Patients with fractures other than hip fractures are less well studied as regards venous thromboembolic complications. Further studies on these fracture patients are warranted.
95 citations
TL;DR: Techniques to increase the efficiency of spermatogonial transplantation and methods to culture the stem cells are focused on, with the possibility of xenogeneic testicular cell transplantation for other species.
Abstract: Recently, we described a method to transplant testicular cells from a fertile donor mouse to the seminiferous tubules of an infertile recipient male, where the donor cells generate spermatogenesis. Spermatozoa produced by the transplanted cells in the recipient testis will fertilize eggs and transmit the donor haplotype to the resulting animals. In the most successful transplantations, up to 80 per cent of progeny sired by the recipient male arise from donor cell-derived spermatozoa. The cell responsible for generation of spermatogenesis following transplantation clearly is a spermatogonial stem cell, since the repopulation of recipient testes extends for periods exceeding 12 months. In the past year, experiments have shown that rat testicular cells transplanted to the seminiferous tubules of immunodeficient mice will generate rat spermatogenesis and produce normal appearing rat spermatozoa, opening the possibility of xenogeneic testicular cell transplantation for other species. In addition, it has proved possible to cryopreserve spermatogonial stem cells for long periods, following which they will produce normal spermatogenesis when transplanted to a recipient. The ability to cryopreserve testicular stem cells makes individual male germ lines immortal. In current work, we are focusing on techniques to increase the efficiency of spermatogonial transplantation and methods to culture the stem cells.
TL;DR: This article examined a series of markers including a cell proliferation marker, neurofilament proteins, and glial fibrillary acidic protein (GFAP) in teratomas at 5, 6, 7, 9, and 12 weeks after rhesus ES cell transplantation into muscles of immunodeficient mice.
Abstract: Primate embryonic stem (ES) cells are capable of indefinite, undifferentiated proliferation and maintain the potential to differentiate to trophoblast and derivatives of embryonic endoderm, mesoderm, and ectoderm. We previously reported that neural differentiation by rhesus ES cells in teratomas includes tissue with a remarkable resemblance to neural tube (Thomson et al. 1995). Here we examine a series of markers including a cell proliferation marker, neurofilament proteins, and glial fibrillary acidic protein (GFAP) in teratomas at 5, 6, 7, 9, and 12 weeks after rhesus ES cell transplantation into muscles of immunodeficient mice. All teratomas examined contained derivatives of all three embryonic germ layers. Neural differentiation included tissues resembling neural tube and embryonic ganglia, as well as individual dispersed neurons, and brain-like gray matter. Tumours of all ages contained neurons and proliferating cells, indicated by staining for neurofilament subunits and Ki67 antigens. Younger tumours contained no or few astrocytes indicated by the absence of GFAP staining, but as these tumours developed, there was an increase in astrocyte differentiation. The results indicate that normal neural differentiation is recapitulated, in part, by the differentiation of rhesus ES cells in teratomas. The differentiation of rhesus ES cells provides an important new model for understanding human neural differentiation.
TL;DR: The results support the concept that similar mechanisms are employed both by the genetically dissimilar fetus and certain tumours to evade immune attack by their host.
Abstract: Three of the proteins protecting cells from autologous lysis by complement are: membrane cofactor protein (MCP; CD46), an inhibitor of the membrane attack complex formation (CD59), and decay accelerating factor (DAF; CD55). We have investigated the expression of these proteins in breast and colorectal carcinoma by immunohistochemistry and immunoblotting of breast tissue for CD46. CD46 was consistently and strongly expressed in the epithelial compartment in 26/28 ductal carcinomas of the breast, 9/9 fibroadenomas, and 9/11 cases of control non-neoplastic breast tissue. CD59 showed a similar degree of expression in the fibroadenomas (9/9), but was less strongly expressed in carcinomatous (22/28) and control (5/11) tissues. In marked contrast, no CD55 expression was detected in tissue from 15 ductal carcinomas. Immunoblotting of breast tissue for CD46 showed the same size of the molecule as for lymphocytes. It had however considerably stronger expression in tumour tissue than in non-neoplastic tissue. CD46 and CD59 were either lacking or only weakly expressed in the epithelial component of control colorectal mucosa: 2/15 and 5/15, respectively. In contrast, tissue samples from colorectal adenocarcinomas showed clear staining for both CD59 (10/18) and, more markedly, CD46 (15/18). There was no association between the pattern or intensity of CD46 and CD59 expression and tumour differentiation. As the complement regulatory proteins CD46 and CD59 are also strongly expressed by trophoblast at the feto-maternal tissue interface, these results support the concept that similar mechanisms are employed both by the genetically dissimilar fetus and certain tumours to evade immune attack by their host.
TL;DR: There is no doubt that testicular cancer is associated with poor gonadal function even before treatment, and epidemiological and clinical data indicate a common aetiology between testicular germ cell cancer and other abnormalities in male reproductive health (such as infertility and cryptorchidism).
Abstract: This paper reviews current knowledge about the effect of testicular germ cell cancer (TGCC) on gonadal function and of cancer treatment on spermatogenesis and Leydig cell function. It is well documented that testicular cancer is associated with impaired spermatogenic function and some patients already have impairment of Leydig cell function before orchidectomy. The degree of spermatogenic dysfunction is higher than what can be explained by local tumour effect and by a general cancer effect, since patients with other malignant diseases have normal, or only slightly decreased, semen quality. Furthermore, sperm counts after orchidectomy are further reduced to less than half of the values in healthy men, even in patients cured from the cancer disease after orchidectomy alone. These observations are supported by histological investigations which have shown a high prevalence of abnormalities of spermatogenesis in the contralateral testis in patients with unilateral TGCC. The association between testicular cancer and poor gonadal function is very interesting both from a biological and from a therapeutic point of view. Firstly, the increase in incidence of testicular cancer has been suggested to be associated with a general decline in male reproductive health and it seems likely that the development of TGCC shares common aetiologic factors with development of other types of testicular dysfunction. This suggestion is supported by the observation that men with various types of gonadal dysfunction such as testicular dysgenesis, androgen insensitivity syndrome, and cryptorchidism have increased risk of testicular cancer. Secondly, the general cure rate in patients with testicular cancer exceeds 90% and the quality of life, including fertility aspects, is therefore important in the management of these patients. Spermatogenesis is already so severely impaired before treatment that fertility is lower than in healthy men. Moreover, radiotherapy and chemotherapy both induce dose-dependent impairment of spermatogenesis and recovery of spermatogenesis after treatment may be long lasting even more than five years in some patients. Sufficient androgen production is seen in the majority of the patients, but some patients suffer from testosterone deficiency. The effect of chemotherapy on Leydig cell function also seems to be dose-dependent. In conclusion there is no doubt that testicular cancer is associated with poor gonadal function even before treatment. Furthermore, the treatment of testicular cancer may have a serious impact on the gonadal function in these patients, most of whom are in the reproductive age. Moreover, the epidemiological and clinical data indicate a common aetiology between testicular germ cell cancer and other abnormalities in male reproductive health (such as infertility and cryptorchidism). These observations are in agreement with the suggestions of hormonal involvement in the aetiology of testicular cancer. Generally, men with TGCC need counselling about their reproductive function with respect to semen cryopreservation, chance of recovery of spermatogenesis, fertility, and the possible need for androgen replacement.
TL;DR: It is indicated that smoking may influence the immune system, leading to increased production of IgM and IgA RF, which is associated with increased incidence of rheumatoid arthritis and joint damage.
Abstract: Smoking has been associated with increased incidence of rheumatoid arthritis (RA), joint damage and positive rheumatoid factor (RF). Here we report an analysis of the association between smoking and IgM, IgG and IgA RF in a cohort of non-rheumatic individuals participating in a prospective longitudinal study of the incidence and significance of elevated RF. From the initial cohort of nearly 14,000 randomly selected individuals aged 52-80 years, 109 RF-positive and 187 RF-negative non-rheumatic participants were recruited. All participants were tested for RF at least twice at an interval ranging from 4 to 13 years. Of the RF-negative participants 21.9% were active smokers compared to 34.1% of IgM RF-positive (p=0.035), 20.8% of IgG RF-positive (N.S.) and 34.4% of IgA RF-positive participants (p=0.047). Smoking was most prevalent (44.8%) amongst participants with elevation of both IgM and IgA RF (p=0.008), and smokers were also significantly more likely to have a persistent elevation of RF than non-smokers (p=0.024). These findings indicate that smoking may influence the immune system, leading to increased production of IgM and IgA RF.
TL;DR: In this paper, a different rationale for the ability of particular hormonal treatments to reverse prolonged azoospermia is presented, in which the block appears to be at the differentiation of the A spermatogonia.
Abstract: Radiation and chemotherapeutic drugs produce prolonged depression of sperm counts in rodents and humans. Previously, three approaches have been developed in experimental animals that have had some success in preventing or reversing this toxicity. These approaches included pretreatment with hormones that suppress spermatogenesis, stimulation of stem cell number, and supplementation with testosterone. A different rationale for the ability of particular hormonal treatments to reverse prolonged azoospermia is presented in this review. In many cases prolonged azoospermia occurs even though the stem spermatogonia survive the toxic insult, but the differentiation of these spermatogonia to produce sperm fails. In the rat, the block appears to be at the differentiation of the A spermatogonia. Hormone treatments with testosterone or with GnRH agonists, which suppress intratesticular testosterone levels, relieve this block and result in the production of differentiating cells. When the hormone treatment is stopped the production of differentiating cells continues, mature sperm are produced, and fertility is restored. If a similar mechanism can be demonstrated to hold in humans, the fertility of men who have been rendered infertile by treatments for testicular and other cancers could be improved.
TL;DR: It is suggested that the invariable 12p amplification noted as early as in carcinoma in situlintratubular germ cell neoplasia (CIS/ITGCN) lesions leads to deregulated overexpression of cyclin D2, a cell cycle G1/S checkpoint regulator with oncogeneic potential which reinitiates the cell cycle.
Abstract: Human male germ cell tumors (GCTs) represent a biological paradox because, in order to develop into a pluripotential tumor, a germ cell destined to a path of limited or no proliferation must acquire the potential for unlimited proliferation. In addition, it must acquire the ability to elicit embryonal differentiation patterns without the reciprocal inputs from fertilization and the imprinting-associated genomic changes which are a part of normal embryonal development. Although much speculated about, the genetic mechanisms underlying these properties of male GCTs remain enigmatic. Recent cytogenetic and molecular genetic analyses of these tumors are providing new insights and new testable hypotheses. Based on our recent work, we propose two such hypotheses. One relates to the mechanism of germ cell transformation and germ cell tumor development. We suggest that the invariable 12p amplification noted as early as in carcinoma in situ/intratubular germ cell neoplasia (CIS/ITGCN) lesions leads to deregulated overexpression of cyclin D2, a cell cycle G1/S checkpoint regulator with oncogeneic potential. Such overexpression reinitiates the cell cycle. We visualize this happening during the pachytene stage of meiosis through aberrant recombinational events which lead to 12p amplification. The other hypothesis relates to the origin of primary extragonadal GCTs. By comparing cytogenetic changes in primary mediastinal versus gonadal lesions, we propose that, in contrast to long-standing speculation that primary extra-gonadal tumors arise from embryonally misplaced primordial germ cells, these lesions arise from migration of transformed gonadal germ cells.
TL;DR: A 10‐year retrospective survey was undertaken of patients with pyogenic hepatic abscesses (PHA), finding that laboratory tests were compatible with infection, slightly elevated alkaline phosphatase being the only test pointing towards the liver as the focus of infection.
Abstract: A 10-year retrospective survey was undertaken of patients with pyogenic hepatic abscesses (PHA). Fifty-two patients fulfilled the criteria of PHA, equivalent to a mean annual incidence of 11/1,000,000. The main symptom was fever. Laboratory tests were compatible with infection, slightly elevated alkaline phosphatase being the only test pointing towards the liver as the focus of infection. Forty-one patients (79%, 95% CL, 68-90%) had positive cultures from aspirated pus, with a total of 79 isolates. Enteric Gram-negative rods accounted for 45% and anaerobic bacteria for 31% of PHA isolates. Gram-positive cocci, predominantly non-haemolytic streptococci, were the third largest group (19%), but were rare among blood isolates. Positive blood cultures were found in 21 patients (40%, 95% CL, 27-54%), with a total of 28 isolates. Percutaneous drainage was performed in 26, percutaneous needle aspiration in 10, combinations thereof in 5, and abdominal surgery in 5. Forty-nine patients received systemic antibiotic therapy, four of whom were treated with antibiotics only. Seven recurrences occurred and the overall case fatality rate was 6% (95%, CL 0-12%), which might reflect a low rate of underlying malignant diseases in our study material.
TL;DR: Even though B1‐PCR performed on amniotic fluid samples did not detect all infected infants, it represented a valuable tool in addition to conventional methods in the diagnosis of congenital T. gondii infection.
Abstract: As part of a screening project for detection of Toxoplasma gondii infection among pregnant women in Norway, nested polymerase chain reaction (PCR) aimed at the detection of T. gondii in amniotic fluid samples was included in the diagnostic routine. The results were compared with the routine criteria for congenital infection: i) T. gondii detected in amniotic fluid or cord blood by mouse inoculation, ii) specific IgM or IgA in serum collected after birth, and/or iii) specific IgG persisting beyond one year of age. The PCR was based on the B1 gene with an internal control gene amplified together with the B1 gene. One hundred and two amniotic fluid samples collected during pregnancy and/or at delivery from 67 pregnant women with serological evidence of primary T. gondii infection were available for examination by both B1-PCR and mouse inoculation. Six samples were positive and 86 samples were negative by both methods (90% concordance). One sample was mouse inoculation positive and B1-PCR negative while nine samples were B1-PCR positive and mouse inoculation negative, of which five were associated with four infants without proven infection. 59%, and 41% of samples associated with infected infants were positive by B1-PCR and mouse inoculation, respectively. The difference was mainly due to a lower detection rate by mouse inoculation after antiparasitic treatment. The specificity of B1-PCR was 94%. Even though B1-PCR performed on amniotic fluid samples did not detect all infected infants, it represented a valuable tool in addition to conventional methods in the diagnosis of congenital T. gondii infection.
TL;DR: The prevalence of contralateral TIN accords well with the known prevalence of bilateral testicular tumours and the feasibility of early detection of testicular cancer in a high‐risk population by means of searching for TIN is shown.
Abstract: Purpose: Testicular intraepithelial neoplasia (TIN; so-called carcinoma in situ of the testis), the precursor of testicular germ cell neoplasms can be detected by testicular biopsy many years before the clinical manifestation of the tumour. This study looked at the prevalence of contralateral TIN in patients with testicular germ cell cancer. The purpose was to evaluate this new approach of early detection of testicular cancer and to evaluate the current management strategies. Patients, methods: 1954 consecutive patients with unilateral testicular germ cell tumour underwent contralateral biopsy. All specimens were examined immunohistologically with staining for placental alkaline phosphatase. Patients with TIN were usually submitted to low-dose radiotherapy of the testis. A rebiopsy was performed after 3 months. Endocrinological evaluations were done before, during and after treatment. Results: TIN was observed in 4.9% (95% confidence intervals 3.95% - 5.91%). Testicular atrophy constitutes a 4.3 fold increased risk of having contralateral TIN. 64% of the cases with TIN were found in clinically normal testes. Patients with TIN were significantly younger than those without (p<0.017). No case with TIN was found in patients older than 50 years. Three patients developed a second testicular tumour during follow-up despite a negative biopsy. After radiotherapy, all of 23 patients had complete disappearance of TIN in the rebiopsy. After chemotherapy, 3 of 10 patients had persistent TIN histologically. After radiotherapy, 12 of 41 patients required testosterone replacement. Conclusion: The prevalence of contralateral TIN accords well with the known prevalence of bilateral testicular tumours. Testicular atrophy is a strong indicator for the presence of TIN but about 60% of TIN-cases occur without atrophy. Local radiotherapy to the testis with 18 - 20 Gy is efficaceous in eradicating TIN, but it causes significant damage to almost one quarter of these patients. Chemotherapy is an unsafe treatment for TIN. This study shows the feasibility of early detection of testicular cancer in a high-risk population by means of searching for TIN. Although the management of the condition still needs refinement, the TIN-concept offers an avenue for the early detection of testicular cancer and early conservative management.
TL;DR: It is shown that life time exposure to environmental factors which are associated with the incidence of testicular cancer appear to be more related to birth cohort than to year of diagnosis.
Abstract: The incidence of testicular cancer is rising in most Western populations. A collaborative study between nine population-based cancer registries in countries around the Baltic Sea was utilized in order to analyze in detail geographic variations and temporal trends in the occurrence of testicular cancer. There were 34,309 cases registered up until 1989 starting in Denmark in 1942 and most recently in Latvia in 1977. From the descriptive epidemiology it was obvious that there was a substantial variation in the age-standardized incidence amounting to about a 10-fold difference between the different countries ranging from 0.8 per 100,000 person-years in Lithuania to 7.6 per 100,000 person-years in Denmark. Previous studies have indicated that this increase is due to birth cohort effects. A more detailed analysis was therefore performed in those six countries with a sufficiently long period of cancer registration; Poland, former East Germany, Norway, Finland, Denmark and Sweden. This analysis showed that birth cohort is a more important determinant of testicular cancer risk than year of diagnosis. In Poland, former East Germany and Finland, there was an increasing risk for all birth cohorts. Among men born in Denmark, Norway or Sweden between 1930 and 1945, this increasing trend in risk was interrupted in these birth cohorts but followed thereafter by an uninterrupted increase by birth cohort. In conclusion, life time exposure to environmental factors which are associated with the incidence of testicular cancer appear to be more related to birth cohort than to year of diagnosis. Because testicular cancer typically occurs at an early age, major etiological factors therefore need to operate early in life, perhaps even in utero.
TL;DR: No genomic region gives overwhelming support for a testicular cancer predisposition gene, but several regions, notably on chromosomes 3, 5, 12 and 18 show suggestive evidence worthy of further examination.
Abstract: Although the aetiology of testicular cancer is unknown, a clear familial component has been identified in a number of studies. In an effort to identify susceptibility genes for testicular cancer, the International Testis Cancer Linkage Consortium has been collecting families with multiple cases of testicular cancer. These families have been genotyped for a set of markers across the genome in two separate studies. The family information has also been pooled across the two studies so that the combined evidence can be assessed. While no genomic region gives overwhelming support for a testicular cancer predisposition gene, several regions, notably on chromosomes 3, 5, 12 and 18 show suggestive evidence worthy of further examination. The Consortium is now attempting to identify further families in an attempt to confirm or deny these leads.
TL;DR: P53‐regulated genes are not correspondingly over‐expressed in germ cell tumour samples and cell lines, indicating that p53 functions poorly as a transcription factor in this tumour type.
Abstract: P53 tumour suppressor gene mutations occur in approximately 50% of common solid tumours such as breast, colon and lung. In contrast, p53 gene mutations occur infrequently (<:3%) in germ cell tumours, even though p53 protein is expressed at high levels in the vast majority of tumour samples. P53-regulated genes are not correspondingly over-expressed in germ cell tumour samples and cell lines, indicating that p53 functions poorly as a transcription factor in this tumour type. High levels of wild-type p53 may contribute, in part, to the chemosensitivity of germ cell tumours.
TL;DR: This work has identified the fibrillar filaments themselves, the PilT protein and the ComP protein as essential components for the DNA uptake phase of competence for natural transformation and the complex interactions which exist between these essential constituents.
Abstract: A combined effort integrating studies of gonococcal Tfp biogenesis, the data made available from the gonococcal genome sequence project and applied molecular genetics have been used to identify the fibrillar filaments themselves, the PilT protein and the ComP protein as essential components for the DNA uptake phase of competence for natural transformation. Our ongoing studies are focused on identifying and understanding the complex interactions which exist between these essential constituents. These studies may be relevant not only to the early steps of genetic transformation but also to the two other venues for horizontal gene transfer based on recent findings. First, the thin pili of IncI1 conjugal plasmids required for liquid mating belong to the type IV family of pili (Yoshida et al., 1998). Secondly, type IV pili are required for lysogenic conversion of Vibrio cholerae by a filamentous phage encoding cholera toxin (Waldor and Mekalanos, 1996). How these highly conserved surface organelles contribute to such diverse forms of DNA translocation across membranes remains to be seen.
TL;DR: It seems very clear that integrons and associated programmed transfer mechanisms have high significance for the dissemination of antibiotic resistance genes in bacteria whereas further studies are needed to assess their importance for spreading of arbitrary genes in a wider range of host systems.
Abstract: The potential of integrons and connected programmed rearrangements formediating horizontal gene transfer.
TL;DR: The present method for producing large amounts of cystic forms of B. burgdorferi is well suited for further studies of this unique microbe.
Abstract: Mobile Borrelia burgdorferi were transferred to distilled water (10(6) per ml). The cultures were observed by dark field microscopy (DFM), interference contrast microscopy (ICM) and transmission electron microscopy (TEM). 95% of the spirochetes were converted to cysts after 1 min, and after 4 h no normal mobile borreliae were observed. When transferred to growth medium (BSK-H), the cysts became smaller and more irregular, and were filled with organic substances. After 1 day, 1-5 thin structures sprouted from the cysts. They continued to grow in both length and thickness until they attained a normal spirochetal structure. Finally, these new-born spirochetes detached from the cysts, by which time their mobility had become normal. The present method for producing large amounts of cystic forms of B. burgdorferi is well suited for further studies of this unique microbe.
TL;DR: Chemoresistance to DNA damaging agents might be reflected by the expression of p53 and bcl‐2 in primary tumours and metastatic lesions in order to identify patients early with primary or secondary chemo‐resistance.
Abstract: The role of p53 in testicular germ cell tumours is still contradictory based on the finding of immunohistochemical overexpression at the protein level, but lack of mutations at the DNA level. In addition, p53 wild-type activity has been demonstrated in cell culture experiments. Overexpression of the proto-oncogene bcl-2 might block p53-induced apoptosis and might inhibit p53 functional activity. To clarify the apparent paradox with respect to p53 overexpression and lack of mutations, an immunohistochemical and mutational analysis of p53 and bcl-2 in TGCT was performed. Ten normal testes, 52 CIS and 151 clinical stage I nonseminomatous GCTs were included in our study. A commercially available anti-p53 polyclonal rabbit antibody and an anti-bcl-2-mouse monoclonal antibody were used to stain the 5pm sections. Staining was assessed by counting at least 500 cells from the area of the most intense staining in each tumour cell type, and this was scored semiquantitatively for intensity of staining on a 4 point scale. In addition, 30 primary GCTs were included in the mutational analysis: areas with p53 overexpression were identified and microdissected prior to DNA extraction. p53 exons 5-8 were amplified by polymerase chain reaction (PCR) followed by single strand conformation polymorphism analysis. Templates demonstrating band shifts on SSCP were subjected to direct DNA sequence analysis. None of the normal testes, 32/52 (62'Ki) CIS, and 142/151 (94%) germ cell tumours exhibited p53 overexpression. p53 expression was significantly lower in mature teratomas (0.8±0.2) than in other germ cell tumour components (2.8±1.2, p>0.001). PCR-SSCP did not reveal any missense mutations or deletions for the p53 gene. Bcl-2 protein expression was observed in none of the normal testes, in none of the CIS, and in 14/151 (9.3/u) germ cell tumours. 13/14 germ cell tumours demonstrated bcl-2 expression only in the glandular and stromal elements of their teratomatous components whereas all other components were negative for bcl-2. Our results - p53 overexpression, lack of p53 mutations, undetectable bcl-2 are consistent with recent in vitro studies. High susceptibilty of testicular cancer to drug-induced apoptosis appears to be the result of wild-type p53 and lack of bcl-2. Radiation and chemotherapeutic insensitivity of mature teratomas might be the result of bcl-2 overexpression and lack of p53 overexpression. Therefore, chemoresistance to DNA damaging agents might be reflected by the expression of p53 and bcl-2 and it might be useful to evaluate p53 and bcl-2 in primary tumours and metastatic lesions in order to identify patients early with primary or secondary chemoresistance.
TL;DR: Cervical HPV infection was the out-standing risk factor for all grades of neoplasia, the association being strongest for HSIL and women with high-risk HPV infection had a nearly 33-fold increased risk of HSIL compared to HPV-negative women.
Abstract: With the overall goal of elucidating the risk factor pattern for cervical neoplasia, two case-control studies and a prospective cohort study were conducted. The first case-control study focused on female lifestyle risk factors. It was designed to include all women (aged 20-49 years) in Greater Copenhagen, diagnosed with invasive cervical cancer or carcinoma in situ (CIS) from January 1985 to December 1986. They were identified from the Danish Cancer Registry. An age-stratified control group was randomly selected from the study area by means of The Danish Central Population Register. Information on risk factors was collected using a self-administered questionnaire. The study, which included 586 women with CIS, 59 women with cervical cancer, and 614 control subjects, confirmed that CIS and invasive cervical cancer share similar risk factors. Both disease entities were strongly associated with sexual and venereal factors. This applied especially to lifetime number of sexual partners and age at first episode with genital warts (proxy measure for human papillomavirus (HPV)), supporting that HPV infection in the adolescent cervix is associated with a higher risk of cervical neoplasia compared with such an infection later in life. Our results also suggested that parity, oral contraceptive use, and smoking may be important risk factors. In the second case-control study, we identified all women with one lifetime sexual partner based on the questionnaire information obtained in the first case-control study. To investigate the role of the "male factor", the women were invited to participate in the study together with their husband. In all, 41 case couples and 90 control couples were enrolled. Data collection included a personal interview, blood samples, and penile swabs from the males. The most significant risk determinants of cervical neoplasia were a history of genital warts in the male and non-use of condoms, emphasizing the venereal nature and pointing to HPV as an important agent. Genital warts are usually associated with the low-risk HPVs (types 6 and 11) rather than with the high-risk HPV types. However, an explanation for the observed relationship between risk of cervical neoplasia and genital warts in the woman herself and in her male partner could be, that they are more likely also to harbour the high-risk HPV types. Only 2 case husbands and no control husbands had HPV DNA detected in the penile swabs (ViraPapR, ViraTypeTM). As the number of cells in the swab always exceeded 3 x 10(4), the result may reflect shortcomings in the test kit used. From our population-based prospective cohort study of 11,088 women, we selected the prevalent cases (199 women with LSIL/HSIL(low-grade/high-grade squamous intraepithelial neoplasia), 131 women with ASCUS (atypical squamous cells of undetermined significance)), and 1000 random controls (women and normal cervical cytology). At enrollment, the women were personally interviewed and had a gynecological examination including cervical swabs for HPV testing and a Pap smear. HPV DNA detection was done using polymerase-chain-reaction methods. Cervical HPV infection (especially with the high-risk types) was the out-standing risk factor for all grades of neoplasia, the association being strongest for HSIL. Women with high-risk HPV infection had a nearly 33-fold increased risk of HSIL compared to HPV-negative women. Possible risk factors for cervical neoplasia in HPV-positive women included smoking, non-use of barrier contraceptives and parity. If analysis was restricted to histologically confirmed high-grade lesions, the proportion of cases that could be attributed to HPV infections was 80%. The importance and urgent need for studies which include HPV as an adjunct to cervical cytology is emphasized. Greater effort should be made to determine the usefulness of this modality (HPV diagnostics) in cervical cancer screening or in the management of cervical neoplasia, especially ASCUS and LSIL.
TL;DR: The results suggest that germ cell survival or death at each stage of differentiation is precisely controlled by specific signalling pathways which consist of a number of molecules.
Abstract: A large number of primordial germ cells (PGCs), as well as spermatogonia, undergo programmed cell death or apoptosis in the physiological context. In this process, environmental, cytoplasmic and nuclear factors are involved. Bcl-2 and its related molecules are known as general regulators of cell death, and some are important for survival of PGCs and spermatogonia. Steel factor, a ligand for c-Kit, also supports growth and survival of these cells. In addition, bone morphogenetic protein (BMP)8B and Desert Hedgehog (Dhh), which are secreted proteins, and a nuclear factor, c-Myc, play a role in spermatocyte survival. This suggests that germ cell survival or death at each stage of differentiation is precisely controlled by specific signalling pathways which consist of a number of molecules.
TL;DR: The viability of the VNC (viable nonculturable) state was assessed by studying the reduction of tetrazolium salts INT (p‐iodonitrophenyl tetrazlium violet) and CTC (cyanoditolyl tetrazoium chloride) to their respective formazans and this was linked to the cellular respiration.
Abstract: Studies were conducted following the formation and characterization of the coccoid morphology of Helicobacter pylori. H. pylori ATCC43504 was incubated in brucella broth plus 2% fetal calf serum at three different temperatures: 37°C, room temperature and 4°C in a microaerophilic environment, and readings were taken at 2, 7, 15, 30 and 45 days. At control times, the total and the viable count, viability tests with tetrazolium salts, and ultrastructural studies were carried out. On solid media, H. pylori became nonculturable after 7 days of incubation at room temperature and 4°C, and after 15 days of incubation at 37°C. At these times of incubation, after subculturing in liquid medium under the same conditions, the growth of H. pylori was detected until the 15th day from cultures incubated at 4°C and until the 30th day from cultures stored at 37°C, and at room temperature. Ultrastructural studies showed a gradual reduction of integrity of bacterial cells that remained stable at 30 and 45 days of incubation: 30% of whole cells of bacteria incubated at 37°C and room temperature and 50% in bacteria incubated at 4°C. The viability of the VNC (viable nonculturable) state was assessed by studying the reduction of tetrazolium salts INT (p-iodonitrophenyl tetrazolium violet) and CTC (cyanoditolyl tetrazolium chloride) to their respective formazans and this was linked to the cellular respiration. At 45 days of incubation, when bacterial regrowth was not observed in solid or in liquid medium, different resuscitation methods were applied to evaluate a possible resuscitation of VNC H. pylori. No significant growth on solid medium was observed.