Showing papers by "University of Bern published in 1988"

A new periacetabular osteotomy for the treatment of hip dysplasias. Technique and preliminary results.

Abstract: A new periacetabular osteotomy of the pelvis has been used for the treatment of residual hip dysplasias in adolescents and adults. The identification of the joint capsule is performed through a Smith-Petersen approach, which also permits all osteotomies to be performed about the acetabulum. This ost

A novel neutrophil-activating factor produced by human mononuclear phagocytes.

Abstract: The biological properties of a neutrophil-activating factor (NAF), which was recently identified as a novel peptide of approximately 6,000 mol wt, are described. NAF is produced de novo by human blood monocytes upon stimulation with LPS, PHA, and Con A. It induces two main responses in human neutrophils, i.e., exocytosis (release from specific granules in normal, and from specific and azurophil granules in cytochalasin B-treated cells) and the respiratory burst (formation of superoxide and hydrogen peroxide). The action of NAF appears to be mediated by a surface receptor as shown by the following observations. (a) NAF induces a rapid and transient rise in cytosolic free Ca2+; (b) interaction with NAF results in desensitization, since the cells do not respond to a second NAF challenge; and (c) the respiratory burst elicited by NAF is similar in onset, and time course to that induced by C5a or FMLP. The NAF receptor can be distinguished from the receptors of C5a, FMLP, platelet-activating factor, and leukotriene B4 by the lack of cross-desensitization. Unlike C5a, the other host-derived neutrophil-activating peptide, NAF is not inactivated by serum and thus presumably accumulates in inflamed tissue.

Morphometry of the human pulmonary acinus

Abstract: The geometry and morphometry of intraacinar airways in human lungs were studied on silicone rubber casts from two adult lungs. We defined acini as the complex of alveolated airways distal to the terminal bronchioles--that is, beginning with the first-order respiratory or transitional bronchiole. The morphological properties of pulmonary acini are described. The acinar volume averages 187 mm3 (SD +/- 79 mm3). Intraacinar airways branch dichotomously over about 9 generations (range 6-12). The internal airway diameter falls from 500 micron to 270 micron between acinar generations 0 and 10, whereas the outer diameter (including the sleeve of alveoli) remains constant at 700 micron. Towards the periphery the size of alveoli increases and clusters of alveoli become more numerous. The longitudinal path length of acinar airways (defined as the distance along the ducts from the transitional bronchiole to the alveolar sacs) averages 8.8 mm (+/- 1.4 mm). The morphometric data collected in this study are used to construct an idealized model of human acinar airways that can be related to existing models of the human bronchial tree.

Application of the Cavalieri principle and vertical sections method to lung: estimation of volume and pleural surface area

Abstract: A practical methodology is proposed for the stereological analysis of lung and other organs using recently developed unbiased procedures. This study concentrates on the unbiased estimation of lung volume using Cavalieri's principle compared with the fluid displacement method and measurement of pleural surface area using vertical sections. Furthermore, the proposed design, in addition to the sampling of extensive slices for the initial steps, also allows sampling of vertical sections for light and electron-microscopical stereology. The procedures are described in detail by reference to biological data from the right lungs of four rabbits. We found excellent agreement between estimates of lung volume measured with Cavalieri's principle and those measured by fluid displacement. Pertinent details of the statistical analysis of the sources of variation (namely biological, systematic sectioning and point-counting variation) are given in an appendix.

Latissimus dorsi transfer for the treatment of massive tears of the rotator cuff. A preliminary report.

Abstract: Symptomatic irrepairable rotator cuff tears usually entail complete loss of the substance of the supraspinatus and infraspinatus tendons. Loss of external rotation control and cranial migration of the humeral head on attempted flexion or abduction of the shoulder are the functional hallmarks. Transfer of the latissimus dorsi tendon from the humeral shaft to the superolateral humeral head provides a large, vascularized tendon that can be used to close a massive cuff defect and that exerts an external rotation and head-depressing moment that allow more effective action of the deltoid muscle. This procedure was carried out in 14 patients without any significant complications. Pain relief and functional results in those four cases with a minimum follow-up period of one year (average, 14 months) compared favorably with alternative treatment methods and warrant further anatomic, electromyographic, and clinical investigation.

Porous hydroxyapatite and tricalcium phosphate cylinders with two different pore size ranges implanted in the cancellous bone of rabbits: a comparative histomorphometric and histologic study of bony ingrowth and implant substitution

Abstract: To investigate the histophysiology of implant degradation, hydroxyapatite and tricalcium phosphate cylinders with a diameter of 3 mm were implanted in the cancellous bone of the distal femur and the proximal tibia of 15 New Zealand White rabbits for up to six months. All implants had a homogeneous pore distribution and a porosity of 60%. Ceramics with a pore size range of 50-100 micron and 200-400 micron were compared. Morphometric analysis showed that up to 85.4% of the originally implanted tricalcium phosphate was degraded after six months, whereas the volume reduction of the hydroxyapatite was only 5.4% after the same period. Within the first months bone and tissue ingrowth and implant resorption occurred at a higher rate in the smaller-pored tricalcium phosphate than in the larger-pored material. Hydroxyapatite cylinders with small pores were totally infiltrated by bone or bone marrow after four months, whereas in the larger-pored hydroxyapatite implants tissue did not penetrate all pores after six months and the amount of bone within the implant was small. Scanning electron microscopy of the material before implantation revealed the existence of numerous pore interconnections with diameters of about 20 micron in the smaller-pored ceramics. Such interconnections were rare in the larger-pored implants. The pore interconnections seem to promote vascular and tissue ingrowth and consequently the initial rate of implant resorption. Implant resorption is an active process and involves two different cell types. Acid phosphatase-positive osteoclast-like cells suggesting active resorption adhere directly to the surface, especially in tricalcium phosphate implants. Clusters of macrophages tightly packed with granular material are found in the pores and along the perimeter of all implant cylinders. They may play an active role in the intracellular degradation of small detached ceramic particles.

On the epidemiology of running injuries The 1984 Bern Grand-Prix study

Abstract: Using a survey questionnaire design, we investigated the incidence, site, and nature of jogging injuries among all participants of a popular 16 km race. The response rate was 83.6%. Of 4,358 male joggers, 45.8% had sustained jogging injuries during the 1 year study period, 14.2% had required medical care, and 2.3% had missed work because of jogging injuries. Occurrence of jogging injuries was independently associated with higher weekly mileage (P less than 0.001), history of previous running injuries (P less than 0.001), and competitive training motivation (P = 0.03). Higher mileage was also associated with more frequent medical consultations due entirely to jogging-related injuries. In 33 to 44 year olds (N = 1,757), the number of years of running was inversely related to incidence of injuries (P = 0.02). Injuries were not significantly related to race running speed, training surface, characteristics of running shoes, or relative weight. Achillodynia and calf muscle symptoms were the two most common overuse injuries and occurred significantly more often among older runners with increased weekly mileage. We conclude that jogging injuries are frequent, that the number of firmly established etiologic factors is low, and that, in recommending jogging, moderation should be the watchword.

Genetic engineering of Schizosaccharomyces pombe: a system for gene disruption and replacement using the ura4 gene as a selectable marker.

Abstract: A system is described for gene disruption and replacement in Schizosaccharomyces pombe based on the homologous selectable marker, ura4, the structural gene for orotidine-5'-phosphate decarboxylase The presence of a single copy of the wild-type gene can rescue a ura4 auxotrophic mutant Furthermore, ura4- cells can be selected for in the presence of 5-fluoroorotic acid (5-FOA) This allows a convenient means of selecting for both forward and backward mutations The sequence of a 18 kb HindIII fragment which contains the functional gene is reported It encodes a single open reading frame of 264 amino acids which shows considerable conservation with the orotidine-5'-phosphate (OMP) decarboxylases from other organisms The ura4 transcript is approximately 850 nucleotides long It begins 51 bp upstream of the protein coding sequence and is unusual in that transcription termination occurs at or very close to the translational stop codon To facilitate the use of ura4 in gene disruption experiments we have also constructed a novel strain of S pombe called ura4-D18, in which the 18 kb HindIII fragment has been deleted from the chromosome Using a combination of this strain and vectors containing ura4 as a selectable marker, we present a general method for targeting recombination events to the chromosomal locus under investigation

Mather Sets for Twist Maps and Geodesics on Tori

Abstract: The title refers to a theory which is based on independent research in three different fields—differential geometry, dynamical systems and solid state physics—and which has attracted growing interest and research activity in the last few years. The objects of this theory are respectively: (1) Geodesics on a 2-dimensional torus with Riemannian (or symmetric Finsler) metric. (2) The dynamics of monotone twist maps of an annulus. (3) The discrete Frenkel-Kontorova model.

Mechanism of neutrophil activation by NAF, a novel monocyte-derived peptide agonist.

Abstract: The rise in cytosolic free Ca2+, shape change, superoxide formation, and granule exocytosis induced in human neutrophils by N-formyl-Met-Leu-Phe (fMLP) and by a newly discovered activating peptide, neutrophil-activating factor, termed NAF, were compared. NAF was effective in the concentration range of 0.1-10 nM and was 10- to 100-fold more potent than fMLP. In qualitative terms, the single responses to either stimulus were remarkably similar: they showed virtually identical onset and initial kinetics, and were all inhibited by pretreatment of the neutrophils with Bordetella pertussis toxin. In addition, the respiratory burst elicited by either stimulus was inhibited by 17-hydroxywortmannin and staurosporine. Two conclusions are drawn from these results: 1) neutrophil activation by NAF (as by fMLP) is dependent on a GTP-binding protein and on protein kinase C; 2) a similar, or even identical, mechanism of signal transduction must be assumed on stimulation of human neutrophils with NAF, fMLP, and other chem...

Chronology of the pressure-temperature history recorded by a granulite terrain

Abstract: Coronite-bearing anorthositic granulites consisting of olivine, orthopyroxene, clinopyroxene, garnet and plagioclase assemblages are particularly well preserved at Gaupas and Holsnoy in the Bergen Arc of West Norway. The coronites are considered to have formed near T= 900° C and P=10 Kb by two stages of subsolidus reaction from an anorthositic gabbro parent. The first reaction involved ol+plag→cpxI+opxI+sp and the second cpxI+opxI+sp+pl→cpxII+opxII+gn. The incomplete reaction products are preserved to varying extents in different corona structures. Sm-Nd isotopic data for each of four coronas yield precise isochrons, and demonstrate isochronism both between the constituent phases of the corona assemblages and dispersed ground mass phases. Three individual coronas not associated with shear zones yield ages of 907±9 my, 912±18 my and 905±37 my. Eclogite facies mineralogy is developed locally in shear zones, which are shown by Sm-Nd and Rb-Sr analyses to be Caledonian in age. Where relict corona structures survive unsheared within these zones, Nd exchange between the constituent phases cannot be resolved. This observation together with sympathetic Ca/Mg and Sm/Nd zoning preserved at T∼900° C in the garnet mantles of coronites places a limit on the diffusivity of Nd in pyropic garnets which is no higher than published experimental values for Mg in pyrope-almandine garnets. Consequently even in slowly-cooled granulite terrains, garnet grains are expected to yield Sm-Nd chronologies very close to the time of mineral growth.

On the exceedance point process for a stationary sequence

Abstract: It is known that the exceedance points of a high level by a stationary sequence are asymptotically Poisson as the level increases, under appropriate long range and local dependence conditions. When the local dependence conditions are relaxed, clustering of exceedances may occur, based on Poisson positions for the clusters. In this paper a detailed analysis of the exceedance point process is given, and shows that, under wide conditions, any limiting point process for exceedances is necessarily compound Poisson. More generally the possible random measure limits for normalized exceedance point processes are characterized. Sufficient conditions are also given for the existence of a point process limit. The limiting distributions of extreme order statistics are derived as corollaries.

Glutathione deficiency in alcoholics: risk factor for paracetamol hepatotoxicity.

Abstract: Patients chronically abusing ethanol are more susceptible to the hepatotoxic effects of paracetamol. This could be due to an increased activation of the drug to a toxic metabolite or to a decreased capacity to detoxify the toxic metabolite by conjugation with glutathione (GSH). To test these hypotheses paracetamol 2 g was administered to five chronic alcoholics without clinical evidence of alcoholic liver disease and five control subjects. The urinary excretion of cysteine- plus N-acetyl-cysteine-paracetamol, the two major products of detoxification of the reactive metabolite of paracetamol, was not significantly higher in chronic alcoholics arguing against a substantially increased metabolic activation of paracetamol. Chronic alcoholics had significantly lower plasma concentrations of GSH than healthy volunteers, however (4.35 (1.89) microM v 8.48 (2.68) microM, p less than 0.05) before the administration of paracetamol, and plasma GSH reached lower concentrations in the alcoholics after paracetamol (2.40 (1.36) v 6.26 (2.96) microM). In a group of patients with alcoholic hepatitis intrahepatic GSH was significantly lower than in patients with chronic persistent hepatitis and patients with non-alcoholic cirrhosis, suggesting that low plasma GSH in alcoholics reflects low hepatic concentrations of GSH. The data indicate that low GSH may be a risk factor for paracetamol hepatotoxicity in alcoholics because a lower dose of paracetamol will be necessary to deplete GSH below the critical threshold concentration where hepatocellular necrosis starts to occur.

Information on past solar activity and geomagnetism from 10 Be in the Camp Century ice core

Abstract: A nearly continuous record of the concentration of 10Be from ice-core data is compared with the tree-ring-derived record for 14C over the same period and it is found that short-term trends in these data sets provide a record of solar activity. No definitive relationship between the long-term trends and the geomagnetic dipole moment is found.

Quantitation of structural features characterizing weight- and less-weight-bearing regions in articular cartilage: a stereological analysis of medical femoral condyles in young adult rabbits

Abstract: The structural organization of articular cartilage from the medial femoral condyle of young adult rabbits has been examined after processing according to an improved fixation procedure. By using recently developed stereological methods, a quantitative analysis of chondrocyte number, surface area, volume, and matrix volume per cell was carried out in the light microscope; at the electron microscopic level, quantities of cytoplasmic components within chondrocytes (including organelles) were estimated. These measurements were made for each of the four zones from the (articular cartilage) surface down to the tidemark, and the results (for each zone) were compared between weight- and less-weight-bearing regions. In general, articular cartilage revealed considerable heterogeneity in structure throughout its depth. The number of cells per unit volume is maximal beneath the surface and decreases towards the tidemark. The size of chondrocytes, and the mean matrix volume surrounding each, increases from the surface toward the deeper zones. Comparison between weight- and less-weight-bearing regions reveals striking differences. The numerical volume density of cells in the superficial zone of regions bearing high physiological load is less than half of that in less-weight-bearing regions, chondrocyte death being principally responsible for this reduction. A comparison between the midzones of weight- and less-weight-bearing areas reveals that the former is characterized by a decrease in cell density and an approximately threefold increase in cell size in relation to the latter. The increase in cell volume is attributable principally to an accumulation of intermediate filaments and glycogen particles, and represents an adaptation to increased functional requirements. Near the tidemark, numerical volume densities of chondrocytes in both weight- and less-weight-bearing locations are similar, but the larger cell size in the former still persists.

Global fire at the Cretaceous– Tertiary boundary

Abstract: Cretaceous-Tertiary boundary clays rich in iridium from five sites in Europe and New Zealand were investigated. The clays are found to be 100-10,000-fold-enriched in elemental carbon (mainly soot), which is isotopically uniform and apparently comes from a single global fire. The soot layer coincides with the iridium layer, suggesting that the fire was triggered by meteorite impact and began before the ejecta had settled.

Colonization of osseointegrated titanium implants in edentulous patients. Early results

Abstract: The purpose of this investigation was to study the colonization of newly set implants in edentates and to monitor the development of the predominant subgingival microbiota during the first 6 months of wearing the implants in vivo Microbial samples of the receiving sites were taken one day prior to the insertion with sterile cotton pellets After implantation, one site per implant was sampled with sterile paperpoints once every week for 2 months, and thereafter in monthly intervals up to 180 days A total of 114 samples of 9 sites from 5 patients were evaluated using the darkfield microscope and cultured anaerobically on non-selective and selective media Representative colonies were identified by atmospheric growth capabilities, Gram-staining characteristics and biochemical tests Small amounts of bacteria were collected from the preoperative swabs On an average 86% of the microorganisms were identified morphologically as coccoid cells and over 80% of the cultivated bacteria were Gram-positive facultative cocci After implantation, no significant changes in these proportions could be observed in all but one site In this particular site a steady decrease of coccoid cells and a simultaneous increase of rods was observed after 21 days Actinomyces odontolyticus was first detected at Day 21 and Fusobacterium spp were first detected at Day 42; at Day 120 small spirochetes were found for the first time, pus formation was noted clinically and a pocket probing depth of 6 mm was recorded None of the other sites showed probing depths of over 3 mm or pus formation In these clinically successful sites spirochetes were never seen Fusobacteria could only be detected in 13 of 104 samples Black-pigmenting Bacteroides were found infrequently and no trend of increase was apparent in any site over the 180 days of monitoring

Activation of protein kinase C differentially modulates neuronal Na+, Ca2+, and gamma-aminobutyrate type A channels

Abstract: Xenopus oocytes were used to study the interaction of neuronal quisqualate receptors with neuronal ion channels. Total mRNA was isolated from chick forebrain and injected into Xenopus oocytes. This technique led to the expression of functional voltage-gated Na+ and Ca2+ channels, of ligand-gated gamma-aminobutyrate and kainate receptor channels, and of quisqualate receptors that could activate endogenous chloride channels by means of inositol trisphosphate-mediated Ca2+ release. Exposure of the oocytes to quisqualate decreased the amplitude of the Na+ current and of the gamma-aminobutyrate type A-gated current and increased the amplitude of the Ba2+ current through Ca2+ channels. This modulation of neuronal ion channels by quisqualate could be mimicked by the protein kinase C activator phorbol 12-myristate 13-acetate and the diacylglycerol analogue 1,2-oleoylacetylglycerol. The kainate-gated channel was not affected by these agents. Phorbol esters that do not activate protein kinase C, alpha-phorbol 12-myristate 13-acetate and alpha-phorbol, were without effect. The inhibitor of protein kinase C, tamoxifen, prevented the modulatory effects of phorbol 12-myristate 13-acetate. The present evidence suggests that the activity of the neuronal Na+ and Ca2+ channels and the ligand-gated gamma-aminobutyrate type A receptor channel are under the control of protein kinase C and that neurotransmitters that activate protein kinase C could profoundly affect neuronal signaling.

Regulation of Assimilatory Sulfate Reduction by Cadmium in Zea mays L.

Abstract: Plants cultivated with Cd can produce large amounts of phytochelatins. Since these compounds contain much cysteine, these plants should have an increased rate of assimilatory sulfate reduction, the biosynthetic pathway leading to cysteine. To test this prediction, the effect of Cd on growth, sulfate assimilation in vivo and extractable activity of two enzymes of sulfate reduction, ATP-sulfurylase (EC 2.7.7.4) and adenosine 5′-phosphosulfate sulfotransferase were measured in maize (Zea mays L.) seedlings. For comparison, nitrate reductase activity was determined. In 9-day-old cultures, the increase in fresh and dry weight was significantly inhibited by 50 micromolar and more Cd in the roots and by 100 and 200 micromolar in the shoots. Seedlings cultivated with 50 micromolar Cd for 5 days incorporated more label from 35SO42− into higher molecular weight compounds than did controls, indicating that the predicted increase in the rate of assimilatory sulfate reduction took place. Consistent with this finding, an increased level of the extractable activity of both ATP-sulfurylase and adenosine 5′-phosphosulfate sulfotransferase was measured in the roots of these plants at 50 micromolar Cd and at higher concentrations. This effect was reversible after removal of Cd from the nutrient solution. In the leaves, a significant positive effect of Cd was detected at 5 micromolar for ATP-sulfurylase and at 5 and 20 micromolar for adenosine 5′-phosphosulfate sulfotransferase. At higher Cd concentrations, both enzyme activities were at levels below the control. Nitrate reductase (EC 1.6.6.1) activity decreased at 50 micromolar or more Cd in the roots and was similarly affected as ATP-sulfurylase activity in the primary leaves.

Diversity and complexity

Abstract: GEDII – Gender Diversity Impact – Improving research and ... DArTSeq and Targeted Genotyping. At the core of DArTseq technology, as it was in the case of DArT method, is a genome complexity reduction concept. Many methods have been developed to reduce genome complexity for genomic characterisation, however the DArT methods provide a significant advantage via an intelligent selection of genome fraction corresponding predominantly to active genes.

Incidence of Diabetic Retinopathy and Relationship to Baseline Plasma Glucose and Blood Pressure

Abstract: A nationwide, stratified population sample of 534 diabetic Swiss men and women, aged 35-54 yr, participated in a study of vascular disease. The study was based on a common protocol, standardized examination procedures, and centralized laboratory methods. Patients were chosen from a pool of diabetic Swiss with diabetes greater than or equal to 1 yr. After selection, the participants were classified into groups according to age at diabetes onset (greater than 30 or less than 30 yr) and insulin treatment status. Several variables thought to be related to retinopathy incidence were analyzed at the initial examinations: onset of diabetes before age 30, duration of disease, fasting plasma glucose, blood pressure, and insulin therapy. Follow-up examination of 358 of 458 survivors, with a diabetes duration that averaged 20 yr, showed retinopathy significantly and independently associated with initial fasting plasma glucose, systolic blood pressure, and insulin use but not with diabetes duration. Lower rates of retinopathy development were observed during the follow-up period in diabetic patients on antihypertensive therapy at the baseline examination, suggesting that not only lower fasting plasma glucose and systolic blood pressure levels but also blood pressure therapy itself decreases the incidence of retinopathy.