Showing papers in "Apmis in 1992"

Genetic regulation of the expression of ABH and Lewis antigens in tissues.

Abstract: Sequential appearance of ABH antigens in different animal species shows a progression from tissues of endodermal to ectodermal and finally mesodermal origin, human erythrocytes being the last cells to acquire these antigens. In view of this, ABH antigens should be called tissue or histo-blood group antigens rather than blood group antigens. In addition to the glycosyltransferases encoded by the ABO genes, several alpha-2, alpha-3 and alpha-4-fucosyltransferases are needed to account for the known ABH histo-blood group antigens. The genetic polymorphism of the genes encoding each of these enzymes defines inter-individual differences. In addition, in the same individual various tissues express these antigens in a different way. For each adult epithelial tissue, antigenic expression is related to cell maturation from germinal layer to surface epithelium. Differential expression is also found at various embryonal stages of the same cells. Examples of these phenomena are presented in an effort to gain further insight into the genetic regulation of the expression of these complex oligosaccharide molecules.

Simple mucin-type carbohydrate antigens (Tn, sialosyl-Tn and T) in gastric mucosa, carcinomas and metastases

Abstract: Immunohistochemical study of the expression of simple mucin-type carbohydrate antigens (Tn, sialosyl-Tn, T and sialosyl-T) was performed using specific monoclonal antibodies in the mucosa adjacent to gastric carcinomas histologically appearing unaffected (n = 58), and in primary gastric carcinomas (n = 87) and their metastases (329 lymph nodes and two liver metastases). Normal-looking mucosas: Tn antigen expression was identified in all the cases; sialosyl-Tn in eight cases; T antigen was never expressed and sialosyl-T antigen was observed in four cases; the expression of these antigens was distinctly limited to the cytoplasm, mostly in the supranuclear (Golgi) area. All the mucosas with intestinal metaplasia showed sialosyl-Tn expression in the goblet cells. Gastric carcinomas: 80 cases (91.9%) stained for Tn antigen, 69 cases (19.3%) expressed sialosyl-Tn antigen, 18 cases (20.7%) expressed T antigen and 17 cases (19.5%) stained for sialosyl-T antigen. In contrast to normal mucosa, carcinoma cells expressed simple mucin-type antigens both at the cytoplasm and at the cell membrane. Most primary carcinomas were concurrently stained for Tn and sialosyl-Tn antigens alone (41.1%), or together with T antigen or sialosyl-T antigen (28.7%). We found a close relationship between the expression of simple mucin-type carbohydrate antigens in the primary tumours and their respective metastases. T antigen (and sialosyl-T antigen) expression was correlated with the wall invasiveness of the tumours. The 18 tumours expressing T antigen and 16 out of the 17 tumours expressing sialosyl-T antigen had nodal metastases and/or sialosyl-Tn expression and the aggressiveness of the tumours (wall penetration, lymph node metastasis and venous invasion). No significant differences were observed between positive and negative tumours for Tn, sialosyl-Tn, T and sialosyl-T antigens regarding the morphologic at type, growth pattern, ploidy or lymphoid infiltrate of the primary tumours.

Are Intestinal bacteria involved in the etiology of rheumatoid arthritis

Abstract: Observations in bowel-related joint diseases give support to this hypothesis. In Crohn's disease and ulcerative colitis, the bowel wall inflammation is complicated in about 20% of the patients by joint inflammation. Bowel infection by Salmonella, Shigella and Yersinia can provoke joint inflammation and supports an etiological link between bowel bacteria and arthritis. The arthropathic properties of the most abundant group of intestinal bacteria, i.e. the obligate anaerobic bacteria, were studied in an animal model. Cell wall fragments (CWF), with peptidoglycan as the major component, from some Eubacterium and Bifidobacterium species induced a severe chronic polyarthritis in Lewis rats after a single intraperitoneal injection. Eubacterium was found in numbers of 10(8)-10(9) per gram in stools of healthy subjects and rheumatoid arthritis (RA) patients. CWF of isolated strains of E. aerofaciens were arthropathic. Soluble peptidoglycan polysaccharide complexes (PG-PS) originating from the obligate anaerobic flora were purified from human intestinal contents. PG-PS from ileostomy fluid that proved to be less processed by intestinal enzymes induced chronic arthritis in rats after a single administration in oil in the base of the tail. It was concluded that the human intestinal bowel contains soluble bacterial cell wall products that are arthropathic in an animal model. Peptidoglycan (PG) or its subunits was reported to be present in mammalian tissues. Immunohistochemical studies from our group showed the presence of intestinal PG-PS in sections of normal rat spleen. Bacterial cell wall or PG-induced joint inflammation in rats is proven to be absolutely dependent on functional T cells. T-cell lines were isolated from the lymph nodes of rats with an E. aerofaciens CWF arthritis. A helper T-cell line B13 was in vivo arthritogenic in knee or ankle joints upon intravenous injection in rats and proliferated in vitro on syngeneic spleen cells alone, but was additionally stimulated by intestinal PG-PS and E. aerofaciens CWF. It was postulated that the arthritogenic T cells that seem to be autoreactive are, in fact, recognizing bacterial PG-PS on antigen-presenting cells (APC). It is generally accepted that RA is a T-cell-dependent process and that therefore the reaction is directed at small peptides bound by the major histocompatibility complex of APC. The only peptides present in arthritis inducing intestinal PG-PS and in CWF are PG peptides interlinking the sugar chains. We feel that the immunoreaction against PG peptides plays a pivotal role in experimental and human arthritis of an unknown etiology.

Carbohydrates of human immunodeficiency virus.

Abstract: Elucidation of the mechanism by which viral infection induces the appearance of carbohydrate neoantigens is highly important. Results from such studies could be expected to be significant for a general understanding of the regulation of glycosylation, and perhaps especially important for the understanding of glycosylation in cancer. For anti-viral therapy in AIDS, inhibitors of glycosylation enzymes are very promising as their mode of action may preclude evolvement of resistent HIV substrains, which seems to be a common problem with the reverse transcriptase inhibitors presently used. Successful therapy with glycosylation enzyme inhibitors will, however, require the development of more specific and less toxic compounds. If carbohydrate antigens can elicit a neutralizing immune response in vivo, the possibility exists that carbohydrate neoantigens can be utilized in the construction of a vaccine against AIDS.

Leukocyte traffic to sites of inflammation.

Abstract: The adhesion of circulating leukocytes to the vascular endothelium is essential for effective host inflammatory and immune responses. Adhesion proteins expressed by both the leukocyte and endothelial cell have been well characterized, and studies of these molecules have shown that both cell types are actively involved in regulating these binding events. Most leukocyte (leukocyte integrins) and endothelial cell (vascular selectins, ICAM-1, and VCAM) adhesion proteins increase in expression and function in response to mediators released by inflamed tissues. In contrast, the expression and function of one type of leukocyte molecule, L-selectin (previously called LECAM-1, LAM-1, gp90MEL-14), is "down-regulated" by inflammatory signals. The purpose of this review is to summarize in vitro and in vivo regulatory and functional studies of some of the molecular mechanisms which regulate leukocyte-endothelial cell adhesion, with particular emphasis on L-selectin, and to present a hypothetical model of how these molecules may be orchestrated in vivo resulting in the control of host inflammatory responses.

Utility of an internal control for the polymerase chain reaction

Abstract: The polymerase chain reaction (PCR) was used to amplify a 209 base-pair fragment of Mycoplasma pneumoniae DNA. The amplicon was transferred into a plasmid and a 680 base-pair piece of foreign DNA was inserted between the two amplimer sites. Plasmid DNA was added to the reaction mixture as an internal control for the polymerase chain reaction. Since the original hybridization target sites were included in this construction, one pair of amplimers could be used to amplify both the target DNA and the internal control DNA. Separation of internal control from target DNA after amplification was easily obtained on agarose gel electrophoresis. For the analysis of clinical samples with the polymerase chain reaction, the addition of internal control DNA allowed monitoring of the overall effectiveness of the amplification in each tube. With this technique approximately one-third of the tests were shown to be unsatisfactory due to technical errors or contaminating inhibitors. Adequate internal controls are necessary to avoid false-negative results with the polymerase chain reaction.

Basic biochemistry of cell surface carbohydrates and aspects of the tissue distribution of histo-blood group ABH and related glycosphingolipids.

Abstract: Cell surface carbohydrates may be protein- or lipid-linked. The structural polymorphism of the oligosaccharide chains is extensive due to variations in monosaccharide composition, carbohydrate sequence, branching, linkage position and linkage anomericity. Blood group ABH and related glycosphingolipids show a remarkable tissue-specific expression with possible implications in areas such as transfusion medicine, transplantation surgery and oncology. This communication gives a condensed description of the present knowledge of the tissue-specific distribution of histo-blood glycolipids in humans.

Microbial interaction with animal cell surface carbohydrates.

Abstract: Microbes have selected primarily carbohydrates for attachment to host animal cells. Recent studies have revealed essential characteristics in the recognition of receptor carbohydrates. Of importance is the property of recognizing also sequences placed inside an oligosaccharide chain, which differs from most animal antibodies. This is the basis for series of isoreceptors with the minimum receptor sequence in common but with separate neighbouring groups. There are families of microbial ligands that show different preferences for members within one series of isoreceptors, indicating only slight differences in the complementary binding sites of the proteins. Such differences may explain shifts in the selectivity of separate host tissues for infection. A second characteristic is the low affinity interaction often found where simple receptor-containing saccharides are unable to inhibit attachment. Technical possibilities are rapidly developing for the design of synthetic receptor analogues to be used in the therapy of clinical infections. This is urgently needed in cases where no rational therapy exists today.

Structure and function of L-selectin.

Abstract: The selectins are a newly described family of carbohydrate-binding adhesion molecules involved in the regulation of leukocyte traffic. Selectins are composed of an N-terminal C-type lectin domain, a single EGF domain, a variable number of short consensus repeat (SCR) domains, a transmembrane region and a cytoplasmic tail. L-selectin (LAM-1/LECAM-1/LECCAM-1) is the only selectin expressed on leukocytes, and mediates a number of leukocyte-endothelial interactions, including the binding of lymphocytes to HEV of peripheral lymph node high endothelial venules (HEV), neutrophil rolling, and leukocyte attachment to cytokine-treated endothelium in vitro. Stable transfectants expressing a series of chimeric selectins and deletion mutants were functionally analyzed in order to determine the molecular basis of adhesion mediated by L-selectin. The specificity of adhesion was found to reside entirely within the lectin domain, suggesting that this domain is the only domain of the protein to interact with the carbohydrate ligand. These results make previous observations that certain mAbs which block function map to each of the extracellular domains difficult to interpret. In addition, deletion of the cytoplasmic tail of L-selectin abolished adhesion, without affecting ligand recognition. Thus, each domain of the selectins has an important, but distinct, role in cell adhesion.

Some bacterial parameters influencing the neutrophil oxidative burst response to Pseudomonas aeruginosa biofilms

Abstract: Persistence of bacteria in spite of a normal host immune system and relevant antibiotic treatment is a key problem in many chronic infections, such as the bronchopulmonary P. aeruginosa infection in cystic fibrosis patients. The capability of bacteria to establish themselves in microcolonies or biofilms is an important protective mechanism of the microorganisms. We examined the human PMN oxidative burst response to P. aeruginosa in biofilm and in planktonic form. The PMN chemiluminescence response to P. aeruginosa in biofilms was reduced to 30.5-47.5% (p less than 0.04) and the superoxide response to 85.9% (p less than 0.02) of the response to equivalent numbers of planktonic bacteria. Mechanical disruption of the biofilms before the assays elicited a significantly increased response in the chemiluminescence experiments and to nonopsonized biofilms in the superoxide anion experiments. We conclude that biofilm bacteria, although able to stimulate the PMN, result in a reduced, suboptimal response leading to lack of efficient eradication of the bacteria in the chronic infection.

Mucosal immunity to Pseudomonas aeruginosa alginate in cystic fibrosis.

Abstract: Patients with cystic fibrosis commonly acquire chronic pulmonary infection with alginate-producing Pseudomonas aeruginosa. The infection remains localized at the mucosal surfaces of the airways. Using enzyme-linked immunosorbent assays immunoglobulin concentrations and titers of specific antibodies to purified P. aeruginosa alginate and to P. aeruginosa sonicated antigens were measured in tears, saliva, sputum and serum. CF patients had significantly higher concentrations of IgG, IgA and SIgA in serum and saliva than controls. They also had significantly higher levels of specific antibodies to alginate and sonicated antigen in secretions and serum. Local production of IgA, IgG and IgM antibodies to P. aeruginosa was demonstrated. Only a minor proportion of specific IgA antibodies were present as secretory IgA in tears, saliva and sputum. The ratio of alginate-specific SIgA to specific monomeric IgA in sputum was significantly lower than the similar ratio in saliva, whereas the same ratio for specific P. aeruginosa sonicate antigens was found in saliva and sputum.

Haemagglutination patterns of Helicobacter pylori

Abstract: Thirty-two Helicobacter pylori strains were screened for haemagglutination (HA) activity with erythrocytes of 11 different animal species. Twenty-three strains (72%) that agglutinated human erythrocytes exhibited a broad-spectrum HA profile. Human, guinea pig and bovine erythrocytes high in sialoglycoconjugates were strongly agglutinated by most strains. Except for two, seven strains (22%) that did not agglutinate human erythrocytes exhibited a narrow-spectrum HA profile, commonly not inhibitable by sialoglycoconjugates or N-acetylneuraminlactose (NANLac). Strains were classified into three major HA classes. HA of 10 strains (31%) in class I was inhibited by different combinations of NANLac, orosomucoid or fetuin, but not by asialofetuin, suggesting the presence of sialic acid-specific HAs probably recognizing NeuAc alpha-(2-3)- Gal isomer. Twelve strains (38%) in class II exhibited a different receptor specificity binding to different combinations of NANLac, orosomucoid and fetuin, as well as asialofetuin. No inhibition was observed with 10 strains (31%) in class III; thus, this receptor seems different from both the other classes. Of 21 strains (66%) in classes I and II, HA of 11 strains (34%) was inhibited with NANLac, 14 strains (44%) with orosomucoid and 15 strains (47%) with fetuin. The great heterogeneity observed in HA patterns indicates that the HAs of different strains may recognize a heterogeneous class of sialoglycoconjugates on the erythrocyte membrane.

Oncogene activation in rheumatoid synovium

Abstract: Rheumatoid arthritis (RA) is a chronic systemic disorder that is dominated by the debilitating sequelae associated with the progressive destruction of articular joints. The molecular and cellular basis of rheumatoid joint destruction is characterized by an abnormal expression of oncogenes modulating cellular proliferation and the induction of lysosomal and metalloproteinases. Based on the observation that the synovial hyperplasia in RA is associated with the proliferation of transformed-appearing synovial lining cells and an overexpression of such oncogenes, the possibility that a hitherto unknown HTLV related retrovirus is involved in the etiopathogenesis of RA is discussed.

Proliferative myositis and fasciitis

Abstract: Two cases of proliferative myositis, four cases of proliferative fasciitis and one mixed form of proliferative myositis and fasciitis have been analyzed in terms of cell differentiation and DNA content. Light microscopically, the lesions were characterized by a mixture of proliferating spindle-shaped cells and uni-, bi- or occasionally multinucleated ganglion cell-like cells. The spindle cells showed ultrastructural features and immunohistochemical properties, including an immunoreactivity for smooth muscle-specific actin, indicative of a myofibroblastic differentiation. The ganglion cell-like cells displayed some resemblance to active osteoblasts ultrastructurally and differed immunohistochemically from the spindle cells by being non-immunoreactive for smooth muscle-specific actin. None of the two cell types showed immunoreactivity for desmin, myoglobin or factor VIII RAG. It is suggested that the two cell types represent different lines of cell differentiation. The cytologic features in smears, as seen in two cases of proliferative fasciitis and one case of proliferative myositis, are considered to be characteristic of these lesions and to permit the diagnosis to be made by fine-needle aspiration. In two of the cases, the lesion was diagnosed only cytologically and thereafter disappeared spontaneously within a month. Cytometric DNA measurements, using two different image analysis systems on Feulgen-stained sections and smears, revealed a "diploid" spindle-shaped cell population with a variable proportion of cells with scattered DNA values. The ganglion cell-like cells differed from the spindle cells by having a broad DNA peak in the diploid region and additional peaks in the tetraploid region, as well as a higher proportion of cells with scattered DNA values compared with those of the spindle-shaped cells. The results of the quantitative DNA analysis are well in keeping with the benign and proliferative nature of these lesions. However, with the technique used here, quantitative DNA analysis, does not distinguish these pseudosarcomatous fibrous lesions from diploid and tetraploid soft tissue sarcomas.

Expression of the epidermal growth factor receptor gene in human brain metastases.

Abstract: Biopsy specimens of human brain metastases were examined for amplification and expression of the proto-oncogene c-erbB1 (located on chromosome 7) encoding the epidermal growth factor receptor (EGFR). Moreover, the tumour DNA was also examined for amplification of other cancer-related genes on this chromosome: the proto-oncogene c-met, the gene for platelet-derived growth factor A-chain, and the gene for plasminogen activator inhibitory type 1. All 18 brain metastases demonstrated positive binding of biotinylated EGF on cryosections. Three out of 18 metastases had amplification of the EGFR gene; the other chromosome-7 genes tested were not amplified. Thus, an increased EGFR gene expression seems to be a general finding in a wide range of carcinomas metastatic to the brain, whereas we found only occasional selective EGFR gene amplifications in single cases.

Prevalence of antibodies against heat-stable antigens from Helicobacter pylori in patients with dyspeptic symptoms and normal persons.

Abstract: Heat-stable antigens from Helicobacter pylori were investigated for the detection of serum IgG, IgA and IgM antibodies against H. pylori by an ELISA technique. Antibody titers against H. pylori were measured in 167 dyspeptic patients, of whom 96 were H. pylori positive confirmed by culture or microscopy, and in 482 controls (0-98 years). Increased IgG antibody titers were found significantly more often in dyspeptic patients with active chronic gastritis than in patients with normal morphology, as well as in H. pylori-positive patients as compared to H. pylori-negative patients, independent of the endoscopic findings. The heat-stable antigens were compared with acid glycine-extracted antigens and a high degree of concordance was found in the results obtained with the two antigen preparations. The differences in the IgA antibody titers against H. pylori between H. pylori-positive and H. pylori-negative dyspeptic patients were significant and may be useful to confirm a borderline IgG result. No differences were found in IgM antibody titer between H. pylori-positive and -negative patients. The greatest age-dependent increase in IgG and IgA antibody titers was found in children, and if a lower cut-off level is used for children than for adults, as has been proposed, the proportion of people with increased antibody titers against H. pylori would be almost constant from the age of between five and 10 years until the time between 61 and 80 years. Comparison of H. pylori IgG antibodies with IgG antibodies against Campylobacter jejuni and total antibodies against cytomegalovirus (CMV) showed a greater similarity between H. pylori and C. jejuni (R = 0.51) than between H. pylori and CMV (R = 0.22). This may possibly be caused by cross-reactions between H. pylori and C. jejuni. The H. pylori heat-stabile antigen seems not to be very different from other crude H. pylori antigens like acid glycine-extracted antigens, but purification and characterization of the antigens are needed to improve antibody assays.

Two types of receptors for human plasminogen on group G streptococci

Abstract: To investigate the nature of plasminogen binding to streptococci, strains selected for high reactivity with human plasminogen were examined for binding pattern against a panel of plasminogen fragments. The strains included human isolates of groups A, C and G as well as bovine isolates of group G. All strains reacted substantially with the plasminogen fragment kringle 1–3. Using the miniplasminogen fragment (kringle 5 and the B chain) a small but reproducible uptake was detected for human group G strains but not for group A or C strains. The group G strains of bovine origin on the other hand demonstrated high uptake of miniplasminogen, suggesting the possibility of an alternative plasminogen receptor for this species. This interpretation was supported by blocking experiments with the lysine analogue EACA where low concentrations (1 mM) completely blocked plasminogen binding to human streptococci, whereas a 100-fold higher concentration was needed for bovine group G strains. Scatchard plots with human isolates resulted in straight lines and Kd values were generally in the range of 20–80 nM. The number of receptors was estimated to be 45,000 for a selected group A strain and about 10,000 for the selected group C and G strains. Scatchard analysis with bovine group G isolates on the other hand revealed a two phase interaction, supporting the assumption of two different receptor structures on these strains. Kd for the first phase was estimated to be about 20 nM (10,000–20,000 receptors per bacterium), which was similar to the human strains, whereas the second phase was in the range of 400–500 nM (50,000 and 150,000 receptors per bacterium with two selected strains). Scatchard plots with the miniplasminogen fragment as ligand mimicked the phase two reaction with plasminogen, supporting the concept that this reaction represents a new and not previously described receptor. Both the receptor reacting with the kringle 1–3 portion and the one reacting with the miniplasminogen portion bound plasmin and plasminogen with similar affinity.

Descriptive epidemiology of infections due to thermotolerant Campylobacter spp. in Norway, 1979-1988

Abstract: This report reviews the first ten years of Campylobacter surveillance in Norway. During 1979-1988, a total of 3,545 isolates of thermotolerant Campylobacter spp. were reported. The isolation rate increased from 1.8 per 100,000 persons per year in 1979 to 13.1 in 1988. The highest isolation rate for both sexes occurred during the first five years of life (31.0 per 100,000). A smaller second peak was detected in the age group 15-24 years (11.1 per 100,000). The male-to-female ratio was 1.52:1 for infants less than five years of age, compared with a ratio of 1.35:1 for all ages combined. Thirty-eight percent of the infections had most probably been acquired abroad. The isolation rate in urban areas (12.4 per 100,000) was over twice that observed in rural agricultural municipalities (5.5 per 100,000). However, this difference was largely due to a higher proportion of imported cases in urban areas, only small variations in isolation rate were observed when imported cases were excluded. The seasonal distribution of Campylobacter isolates showed a peak during the warm months of the year. Travel activity during summer holidays did not account for this trend, since the summer peak became even more pronounced when imported cases were excluded. A north-south gradient in the seasonality was observed; when domestic cases were considered, the summer peak became more accentuated with increasing latitude reaching a maximum in subarctic areas. This might be explained by corresponding variations in occurrence of campylobacters in surface water sources.

Alloxan cytotoxicity involves lysosomal damage.

Abstract: The cytotoxic effects of alloxan are not understood in any great detail, although they are considered to involve reactions mediated by oxygen-derived free radicals. These reactive species may form extra-or intracellularly following alloxan reduction, and result in cell damage through a number of complex interactions with a variety of macromolecules. The purpose of the present study was to elucidate further the early intracellular effects of alloxan on a model system of macrophage-like cells in culture. Addition of alloxan (15 mM), without reducing agents, to the medium surrounding the cells (phosphate-buffered saline, PBS, 37 degrees C, pH 7.4) resulted in rapid lysosomal damage (disappearance of the proton gradient over the membrane) followed by severe cellular degeneration (swelling and blebbing) and 50% cell death (trypan blue dye exclusion test) within fifty min. Cells pretreated with the gamma-glutamyl cysteine synthetase-inhibiting agent BSO, to decrease levels of intracellular glutathione, showed enhanced sensitivity to alloxan. The results are interpreted as indicating the cytotoxicity to result from intracellular formation of superoxide radicals, hydrogen peroxide and hydroxyl radicals, the latter within secondary lysosomes containing trace amounts of reactive iron (inducing Fenton reactions). The ensuing lysosomal membrane damage may result in leakage of lysosomal hydrolases and further cellular degeneration.

Carbohydrate changes in colon carcinoma.

Abstract: The colonic epithelium preferentially expresses only certain types of carbohydrate antigens. The most prevalent ones are the lacto-series type 1 (Gal beta 1,3GlcNAc) and type 2 (Gal beta 1,4GlcNAc) chain blood group-related substances, which can reside on both glycolipids and glycoproteins, and mucin-type O-linked structures such as Tn, T, and sialosyl-Tn, which reside exclusively on glycoproteins. This review focuses on the tissue expression in the colon of those carbohydrate tumour-associated antigens which have been most extensively studied and for which the epitope structure has been defined.

Expression of proliferative cell nuclear antigen (PCNA) in urinary bladder carcinoma. Evaluation of antigen retrieval methods.

Abstract: Proliferative cell nuclear antigen (PCNA) expression was analyzed in formalin-fixed and paraffin-embedded specimens from patients with urinary bladder cancer using three different anti-PCNA monoclonal antibodies. In 20 recent cases a positive correlation was found between the extent and intensity of PCNA staining and grade of malignancy. In 95 specimens, three to six years old, extensive positive staining was detected in 15 and 23% of grade 2B and 3-4 tumors, respectively. No equivalent staining was found in the grade 1 and 2A tumors. In material more than six years old, a remarkably weak staining was observed regardless of grade. Similarly, in a test of archival material of tonsils a very weak immuno-reactivity was found as compared with fresh material. However, antigen retrieval by microwave heating of the tissue sections was possible in the majority of all cases, and the difference in extent and intensity of the staining between low and high grade tumors remained.

Cancer-associated changes in glycosylation of fibronectin. Immunohistological localization of oncofetal fibronectin defined by monoclonal antibodies.

Abstract: The extracellular matrix adhesion molecule fibronectin exhibits different isoforms derived by alternative splicing as well as recently demonstrated variation in O-glycosylation. Although fibronectin is widely distributed in normal tissues, the individual isoforms have been found to show restricted tissue distribution and association with malignancies. The monoclonal antibody FDC-6 defines a cancer-associated de novo glycosylation of a specific threonine residue in the C-terminal region of the fibronectin molecule termed oncofetal fibronectin. Here we report an immunohistological study of oral squamous cell carcinomas (n = 33), premalignant lesions (n = 15), and normal oral mucosa (n = 10) using the FDC-6 antibody. A selective expression of the oncofetal fibronectin epitope was demonstrated in close relation to the invading carcinoma, whereas no staining was observed in premalignant lesions without epithelial dysplasia, or in normal epithelium. Furthermore, we attempted to identify additional carbohydrate-related epitopes distinguishing fibronectin of human hepatoma cell line HUH-7 from plasma fibronectin. No novel epitopes were identified, as all generated monoclonal antibodies lacking reactivity with plasma fibronectin showed the same specificity as FDC-6. Previous studies have indicated that the de novo glycosylation is induced by a novel transferase activity only found in fetal and carcinoma cell lines, placenta and hepatoma tissues. Here we provide further evidence that a purified UDP-GalNAc:peptide N-acetylgalactosaminyltransferase from normal bovine thymus and human placentae is incapable of utilizing the hexapeptide VTHPGY as a substrate. The results demonstrate that oncofetal fibronectin is highly associated with malignancy, and appears to be induced by expression of a unique glycosyltransferase or modification of the specificity of the normally expressed transferase.

Origin and evolution of the vertebrate immune system.

Abstract: The immune system is a complex evolutionary unit and it would be simplistic to conclude that the immune systems of all primitive vertebrates are primitive. Because of the large number of elements involved, many evolutionary events must have taken place, some of them neutral, some of them selected, to constitute the systems that we are looking at towards the end of the 20th century. All these systems have perhaps evolved beyond the apparent evolutionary state of the species in which they are found. They have been modulated by factors linked not only to the internal evolution of their elementary genes, but also by coevolution with factors in the internal environment, such as cellular constraints, metabolism, mode of reproduction and progeny size. It seems that good inventions are long lasting, which is the reason why some elements of the invertebrate immune system can be found with similar functions in vertebrates (defensins). It is also the reason why Ig domains have been exploited in so many ways, whether for the immune system or not. Again, they had an evolution of their own. The comparative study of the immune systems carried out on the occasion of this phylogenetic survey shows a world particularly dynamic and diverse. The comparisons between the solutions chosen by the various phyla of the animal kingdom, or closer to us by the various classes of vertebrates, allow us to distinguish the essential features of the immune system. From this viewpoint, this approach is not only of phylogenetic interest, but also has an applied aspect. Increasing our knowledge in this area could help suggest solutions to clinicians when they are faced with deficiencies and abnormalities in the immune system of man.

Pathology of the heart in AIDS

Abstract: Cardiac disease and cardiac death in AIDS patients is seldom reported. In recent years minor cardiac abnormalities have been demonstrated, especially by echocardiography. Cardiac pathology in AIDS patients is here reported from 60 consecutive autopsies where the heart was investigated either using single samples of ventricular myocardium (the first 21 cases) or by an examination of the whole heart (the last 39 cases). Myocarditis according to the Dallas criteria was seen in 25 of 60 cases (42%), and in seven of these cases a probable pathogen (Toxoplasma gondii, cytomegalovirus, fungi) was demonstrated. Diffuse myocardial fibrosis was seen in 40 of 60 cases (67%) and is considered to be partly due to repair after myocyte necrosis/myocarditis. A myocardium thus weakened might not be able to meet an increase in functional demand, and in 15 of the 39 cases (38%) where an examination of the whole heart was performed, there was dilation and/or hypertrophy of the right ventricle. This is in agreement with our knowledge that the main diseases and main causes of death in AIDS patients are pulmonary. Survival time in AIDS is increasing due to ever improving symptomatic treatment, and the results of this study indicate that the prevalence of especially right-sided heart failure will increase.

Glycosylation of neural cell adhesion molecules of the immunoglobulin superfamily.

Abstract: Cell adhesion molecules (CAMs) are believed to play key roles during morphogenesis. In this review we focus on neural CAMs belonging to the immunoglobulin superfamily. Data concerning distribution, expression pattern, structure and function of these CAMs are accumulating these years. In general, little is known about the importance of glycosylation for the function of these CAMs. The neural cell adhesion molecule, NCAM, is probably the best described CAM, and this molecule exhibits special carbohydrate characteristics, e.g. NCAM is polysialylated. Glycosylation of NCAM seems to be regulated during development and to influence the adhesive function of the molecule. Structure, function and glycosylation of NCAM are described in detail.

Fetal antigen 2: An amniotic protein identified as the aminopropeptide of the α1 chain of human procollagen type I

Abstract: Fetal antigen (FA2) was purified from second trimester human amniotic fluid by immunospecific chromatography, gel filtration and reversed-phase chromatography. Gel filtration revealed two molecular forms of FA2 eluting at volumes corresponding to an M(r) of approximately 100 kDa and 30 kDa. SDS-PAGE analysis gave an M(r) = 27 kDa under reducing and non-reducing conditions for both forms, whereas the exact M(r) determined by mass spectrometry was 14,343 +/- 3 Da. FA2 was N-terminally blocked and after tryptic digestion the amino acid composition and sequences of the peptides showed identity with the aminopropeptide of the alpha 1 chain of human procollagen type I as determined by nucleotide sequences. After oxidative procedures normally employed for radio-iodination (iodogen and chloramine-T), FA2 lost its immunoreactivity. An antigen which cross-reacted with polyclonal rabbit anti-human FA2 was demonstrated in fetal calf serum. Gel filtration with analysis of fractions by inhibition ELISA showed that the bovine homologue was present in the same molecular forms as those in human amniotic fluid, and immunohistochemical analysis with anti-human FA2 showed that its distribution in bovine skin was identical to that of FA2 in human skin. FA2 is a circulating form of the aminopropeptide of the alpha 1 chain of procollagen type I, and this is the first description of its isolation and structural characterization in humans.

Serum resistance in Escherichia coli strains causing acute pyelonephritis and bacteraemia

Abstract: The capacity of Escherichia coli to resist the bactericidal action of serum was examined in 367 clinical isolates obtained from children with acute pyelonephritis (n = 57), adults with acute pyelonephritis (n = 55), non-diabetic patients with bacteraemia (n = 101), diabetic patients with bacteraemia (n = 65) and from the faecal flora of healthy controls (n = 89). The incidence of serum-resistant E. coli strains was significantly higher in pyelonephritogenic strains from children and adults (93% and 82%) as compared to faecal control strains (57%, p less than 0.001 and p less than 0.005 respectively). Strains causing bacteraemia in non-diabetic and diabetic patients were more often serum resistant (72% and 80%) as compared to control strains (p less than 0.05 and p less than 0.001 respectively). The frequency of serum-sensitive strains was similar in diabetic patients with decreased renal function or proteinuria compared to those with normal renal function. There were no significant correlations between serum resistance of E. coli and expression of P fimbriae, type I fimbriae or mannose-resistant haemagglutination, cell surface hydrophobic properties, production of aerobactin, haemolysin or cytotoxic necrotizing factor in 53 pyelonephritogenic strains from adult patients.

Redistribution of lymphocytes after cortisol administration

Abstract: Major surgical procedures awake an endocrine metabolic stress response characterized by increased secretion of cortisol and lymphopenia. The purpose of this study was to clarify to which tissues the lymphocytes are redistributed after cortisol administration. Lymphocytes were isolated from 16 rabbits, labelled with indium-111-tropolone and reinjected into the rabbits. Eight of the rabbits received 25 mg of cortisol intravenously (group I), while eight received isotonic saline (group II). The redistribution of lymphocytes was imaged with a gamma camera and calculated by a connected computer before and two, four, and seven h after cortisol or saline administration. The radioactivity of cells from the spleen and bone marrow decreased to 84% and 56% of the initial values seven h after cortisol administration. The activity of the lymphatic tissues increased to 121% of initial values. It is concluded that during cortisol-induced lymphopenia the lymphocytes are redistributed from peripheral blood, spleen and bone marrow to lymphatic tissue.

Murine thymocytes with ability to inhibit I1‐2 production: I. Genetic differences between mouse strains and characterization of the model system

Abstract: An experimental system has been established to understand the poor interleukin-2 (Il-2) production by activated thymocytes. This model system is further characterized here and studies were done on the possible mechanism(s) involved. Thymocytes activated by Concanavalin-A (Con-A), or through the CD3 complex of the T-cell receptor (TCR), inhibit 95-99% of the Il-2 production by spleen cells, while thymocytes stimulated by rIl-2 or lipopolysaccharides (LPS) do not. The mechanism of inhibition is not due to production of soluble factors, consumption of available interleukin-1 (Il-1) or Il-2, but is dependent on cell-to-cell contact. Although cellular contact is needed, cytotoxicity is not involved. Prostaglandin production is not required for the generation or exertion of the inhibitory activity. Protein and DNA synthesis are necessary for exertion of the suppressive effect. We also demonstrate a genetic difference between different mouse strains in the ability to generate the inhibitory thymocytes. Activated Balb/c thymocytes inhibit spleen cells' Il-2 production in a non-MHC-restricted manner. Our studies demonstrate a regulatory capacity of activated thymocytes in vitro. This ability of the postnatal cells could be of relevance for understanding the latter events in T-cell education in the thymus and the role of Il-2 during this process.