Biomedical subjects
Publications and source records attributed to J Stalder.
We report differential scattering experiments on the laser excitation of Na + M collision pairs with M = N(2), CO, C(2)H(2), and CO(2). The collision event is probed by the laser polarization revealing geometric and electronic properties of the collision pair. The experimental data are compared to the results of a Monte Carlo trajectory simulation using ab initio quantum chemical data.
A collaborative study was initiated by the European Directorate for the Quality of Medicines (EDQM) with the goal to calibrate the trivalent candidate European Pharmacopoeia Biological Reference Preparation (BRP) for oral poliomyelitis vaccine (OPV) Batch 3 against the 1st International Standard (IS) for OPV and to establish the material as a working standard. The material is a commercial trivalent stabilised oral poliomyelitis vaccine, consisting of Sabin strains of live attenuated poliovirus types 1, 2 and 3. The new standard is meant to replace the current European Pharmacopoeia BRP for OPV Batch 2, the stocks of which will soon be depleted. Fourteen laboratories participated in the study. Three samples had to be assayed (1st IS, BRP Batch 2, candidate BRP Batch 3). The potency of each virus type in each preparation had to be estimated by using either common monoclonal anti-polio antibody sera and/or the participant's routinely used antisera for neutralizing two of the three virus types present in the trivalent vaccine. In addition the total virus content had to be determined. From the raw data returned, log10 CCID50/ml values were calculated using the probit method (CCID50 is the dose infecting 50% of the cell cultures). The precision (intra-assay variation), repeatability (intralaboratory variation) and reproducibility (inter-laboratory variation) were assessed as absolute titres and as the adjusted titres (potencies of the test samples calculated relative to the 1st IS). An analysis of variance was performed to determine if there were significant differences between assays using mono- or polyclonal antisera. The precision, determined as the width of the uncorrected confidence limits taken across all assays within laboratories, varied on average from +/- 0.13 to +/- 0.34. The repeatability (uncorrected titres) standard deviation varied from 0.08 to 0.27 and was on average 0.174. The repeatability (corrected titres) standard deviation varied from 0.11 to 0.33 and was on average 0.176. In both cases the repeatability standard deviation was very similar when compared between types, between antisera and between samples. None of these differences were statistically significant. The reproducibility (for the corrected titres) was analysed by calculating the standard deviation of the laboratory means which ranged from 0.10 to 0.21 and was on average 0.151. For the corrected titres there is no significant indication that the antiserum type used for neutralisation affects the potency estimate. The study shows that the candidate BRP Batch 3 is suitable as a reference substance and, based on the current results, 6.99, 6.06, 6.83 and 7.20 log10 CCID50/ml are the potencies assigned for Types 1, 2, 3 and total virus content, respectively. Stability data indicate that the candidate material is stable when stored at -20 degrees C. Nonetheless the stability of the new reference preparation will be closely monitored. The candidate material was adopted by the European Pharmacopoeia Commission at its session in March 2002 as European Pharmacopoeia OPV BRP Batch 3.
Viral vaccines have been shown to contain residual host cell-DNA. There is no doubt about uptake and expression of foreign DNA in mammalian cells but the mechanism of transfection is not completely understood. It is suggested that DNA associates with several compounds and is transferred into the cell by endocytosis. In this study we estimate the potential of transfection of several original adjuvants by adding reporter plasmid DNA (pDNA) to vaccines. We used fibrosarcoma cells as an in vitro model and the results indicate that the cells are not able to express pDNA. Therefore we propose that adjuvants included in viral vaccines have no potential to transfect fibroblasts.
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To assess changes of sex hormones, cortisol, prolactin (PRL) and beta-endorphins in an exhaustive aerobic performance, blood samples were taken in 11 endurance trained runners (R) along an ultra-marathon race of 110 km (T1 before the start, T2 at km 33, T3 at km 75 and T4 immediately after completing the race). Results were compared to a control group (C) who followed the race. Cortisol (p < 0.001) and beta-endorphins (p = 0.009) showed a significant increase during the race without significant modification after T2. Testosterone decreased along the race (p = 0.02). Luteinising hormone (LH) was lower at the end of the race as compared to the start in the R. No modification of PRL was noticed in the runners. Most of the modifications except for testosterone were observed from the start to T2, even in exhaustive performance no further modification was noticed from that point onwards.
BACKGROUND: Safety considerations require that biological products for human use are free from any agent that might pose a potential health hazard. One method to detect the presence of retroviral particles is the reverse transcriptase (RT) assay. This assay is capable of detecting all infectious retrovirus particles, irrespective of genome or protein composition. Recently, a family of ultrasensitive RT tests, named product-enhanced reverse transcriptase (PERT) assays, has been designed with a detection limit that is 10(6) - 10(7) times lower than that of conventional RT tests. OBJECTIVES: To investigate with the PERT assay whether RT activity is detectable in live attenuated virus vaccines and to characterize eventual RT activities. STUDY DESIGN: A total of 12 different monovalent and one trivalent virus vaccines containing live attenuated viruses were tested for RT activity with the PERT assay and a conventional RT test. RT activities were investigated with respect to their susceptibility to RT inhibitors, association with physical particles, and their possible origin. RESULTS: One trivalent and five different monovalent vaccines contained RT activity when tested with the PERT assay, but were negative in a conventional RT assay. All lots tested of these vaccines showed RT activity. The activity in all vaccines was sensitive to AZT-triphosphate and ddTTP and at least part of it was associated with particles. Mg(2+)-dependent RT activity banded at a density of 1.14 g/ml. All positive vaccines were produced using chicken cells. CONCLUSIONS: The data indicate the systematic presence of partially particle-associated retroviral reverse transcriptase in attenuated live virus vaccines that are produced in chicken-derived cells. The identification and further characterization of these particles, as well as the elucidation of possible interactions with the human organism are imperative goals despite the fact that these vaccines have been safely used for many years.
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Dr. Narakas intended to study a series of 61 cases of shoulder sequelae of obstetric palsy. His vast experience would have enriched our clinical knowledge of this ailment. The authors carry on with that study to clarify his therapeutic approach and share the benefit of his experience.
Edematous benign polyarthritis of the elderly (syndrome of remitting seronegative synovitis with pitting edema) affects Caucasians aged over 60, predominantly males. The symptoms involve constant edema of the hands and often of the feet, with pain and muscular weakness. These symmetric edemas are accompanied by arthritis of the extremities and the large joints. The onset of the syndrome is acute, ranging from some days to a few weeks, characterized by inflammation but no rheumatoid factor. Treatment is similar to that of the classic form of rheumatoid arthritis. The evolution, however, is always favorable within a year, without subsequent sequelae. The etiology remains undetermined.
A series of 166 perilunate dislocations and fracture-dislocations from 7 centers was retrospectively studied. The diagnosis was missed initially in 41 cases (25%). A classification system was presented. The perilunate fracture-dislocations were more frequent than the perilunate dislocations at a ratio of two to one. The displacement was dorsal in 161 cases (97%) and palmar in only 5 (3%). The dorsal transscaphoid perilunate fracture-dislocations represented 96% of the dorsal perilunate fracture-dislocations and 61% of the whole series. The clinical and radiologic outcome of 115 perilunate dislocations and fracture-dislocations with at least 1 year and an average of 6 years 3 months of follow-up was studied. Open injury and delay of treatment had an adverse effect on clinical results, whereas anatomical type had less influence. In cases treated early, the clinical results were satisfactory but the incidence of post-traumatic arthritis was high (56%). In the dorsal perilunate dislocation group of pure ligamentous injuries and in the dorsal transscaphoid group, the best radiologic results were observed after open reduction and internal fixation. In the latter group, the fixation of the scaphoid alone was not always sufficient and left occasionally scapholunate dissociation, lunotriquetral dissociation, ulnar translation of the carpus, or other carpal collapse patterns. The initial appraisal of both the osseous and ligamentous pathology was very important.
The globin gene clusters of Xenopus laevis are interspersed by various different repetitive DNA elements. A specific repeat, the JH12 element, has been mapped by Southern analysis and some of its locations have been subsequently confirmed by nucleotide sequencing. JH12 family members seem to represent mobile genetic elements and display a high degree of divergence. The nucleotide sequences upstream to the adult beta I-globin gene and to the two coordinately expressed larval beta I- and beta II-globin genes have been determined and compared to those of the adult alpha-genes. Besides some repetitive DNA elements and a short sequence of rather weak homology we have found no characteristic sequence motifs to be common to the adult alpha- and beta-genes. The two larval beta-genes share one short sequence element being absent from the adult genes. This might reflect completely different sequence requirements for protein interactions and for the regulation of adult and larval globin gene expression.
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Insertion of 1.5 kb of the 5' flanking region of the adult alpha-globin gene of X. laevis in front of the CAT structural gene promotes synthesis of CAT in transiently transfected X. laevis kidney cells. Fusion of transiently transfected kidney cells with erythroblasts isolated from anaemic frogs stimulates CAT expression 3-4 fold in the resulting transient heterokaryons. The stimulation is specific for the alpha-globin promoter and is obtained after fusion with erythroid cells but not with hepatocytes or kidney cells. Stably transfected kidney cells express drastically reduced CAT activity as compared with transiently transfected cells. Nevertheless, fusion of stably transfected kidney cells with erythroblasts leads to a 10-17 fold stimulation of CAT expression. The experiments suggest that erythroid specific transacting factors stimulate expression of CAT controlled by the adult alpha-globin promoter.
The globin gene family of Xenopus laevis comprises pairs of closely related genes that are arranged in two clusters, each pair of genes being co-ordinately and stage-specifically expressed. To get information on putative regulatory elements, we compared the DNA sequences and the chromatin conformation 5' to the co-ordinately expressed adult alpha-globin genes. Sequence analysis revealed a relatively conserved region from the cap site up to position -289, and further upstream seven distinct boxes of homology, separated by more diverged sequences or deletions/insertions. The homology boxes comprise 22 to 194 base-pairs showing 78 to 95% homology. Analysis of chromatin conformation showed that DNase I preferentially cuts the upstream region of both genes at similar positions, 5' to the T-A-T-A and the C-C-A-A-T boxes, only in chromatin of adult erythroblasts and erythrocytes, where adult globin genes are expressed, but not in chromatin of adult liver cells or larval erythrocytes, where these genes are silent. This suggests that cell- and stage-specific activation of these genes coincides with specific changes in chromatin conformation within the proximal upstream region. No difference was found in the nucleotide sequence within the DNase I hypersensitive region proximal to the adult alpha 1-globin gene in DNA from embryonic cells, in which this gene is inactive, and adult erythrocytes, expressing this gene.
The 1822 bp sequence of the larval Xenopus laevis beta II-globin gene is reported together with 240 bp upstream of the gene and 190 bp beyond the site of polyadenylation. The mRNA start point was determined by primer extension as well as nuclease S1 mapping and the polyadenylation site by comparison of the gene sequence to the mRNA sequence derived from a corresponding cDNA clone. Like other vertebrate globin genes, this gene comprises three exons interrupted by two intervening sequences (IVS). IVS I spans over 582 nucleotides and interrupts the exon sequences within codon 30. IVS II is located between the codons 104/105 and spans over 617 nucleotides. The 5' region of the gene contains the canonical TATAA homology at position -31. Comparison of the upstream sequence to that of Xenopus laevis larval beta I-globin gene revealed a conserved sequence, located between nucleotide positions -60 and -87, which might function as regulatory element of transcription. Whereas the upstream region of the larval beta II-globin gene does not contain a CAAT box, we notice a reiterated AAATGA motif and discuss its possible significance.
Lymph node involvement in cat scratch disease is characterized by a granulomatous lymphadenitis with micro-abscesses. Recently, it has been shown that the possible aetiological agent is a micro-organism which stains with some silver stains. In this study 60 lymph nodes were studied from 60 patients, using a modified Dieterlé's stain. In 40 cases (66%) rod-shaped bacilli with rounded extremities were observed. They were negative both with the Gram and Ziehl-Neelsen stains. Since such micro-organisms were demonstrated in the majority of the nodes examined, it can be concluded that silver stains are appropriate for the diagnosis of this condition.
The complete nucleotide sequence of the cDNA insert of the clone pXGL25 derived from the larval beta II-globin mRNA of Xenopus laevis has been determined. The sequence of 593 nucleotides represents part of the 5'nontranslated region, the coding region for 146 amino acids and the entire 3'nontranslated region. It diverges from the related larval beta I-sequence by 24.9% in the coding region. Alignment of the 5' and 3'nontranslated regions of the two related larval beta-sequences to maximum matching resulted in 31.2% and 46.7% divergence, respectively. Divergence between the corresponding adult and larval sequences considerably exceeds that of related larval sequences, suggesting that larval genes may have arisen by gene duplication prior to genome duplication. In contrast to mammalian beta-globin mRNAs, replacement and silent base substitutions are equally abundant, thus indicating less functional constraint on the larval Xenopus laevis beta-globin chains. The larval beta I- and beta II-globins diverge by 30.8% and show most variation in the alpha 1/beta 2-chain interaction sites.
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