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Biomedical subjects

M Simon

Publications and source records attributed to M Simon.

At least 361 records · Page 20Linked to original sources
PubMed1991

[Serological study of BoLA class I antigens].

Typing reagents were prepared determining the class I antigens of the main histocompatibility complex in cattle (BoLA). The microcytotoxic test was applied to analyse 450 sera (reagents) obtained from cows postpartum. Testing these sera on the panel of lymphocytes from unrelated animals and calculating mutual correlations of the reactions, we determined 113 groups of similarly reacting sera (clusters) which determine 13 specificities of Class I BoLA complex. The majority of these correspond to the internationally approved BoLA antigens.

Animals↗
PubMed1991

Biotechnology awareness study, Part 2: Meeting the information needs of biotechnologists.

The second part of the biotechnology awareness study focused on health sciences libraries and how well they are meeting the needs of biotechnologists working in the study's nine medical centers. A survey was conducted over a three-month period to assess the demand for biotechnology-related reference services at nine libraries and the sources the librarians used to answer the questions. Data on monographic and current serial holdings were also collected. At the end of the survey period, librarians were asked for their perceptions about biotechnology research at their institutions and in their geographic areas. Their responses were compared to the responses the scientists at the nine schools gave to the same or similar questions. Results showed few biotechnology-related reference questions were asked of the librarians. The recorded questions dealt with a range of biotechnology subjects. MEDLINE was used to answer 77% of the questions received during the survey period. More detailed notes in MeSH and a guide to online searching for biotechnology topics were suggested by the librarians as ways to improve reference service to this group of researchers. Journal collections were generally strong, with libraries owning from 50% to 87% of the titles on a core list of biotechnology journals compiled for this study. All libraries subscribed to the five titles most often cited by the scientists surveyed. Generally, librarians were unaware of the biotechnology-related research being done on their campuses or in their geographic areas.

Awareness↗
PubMed1990

Clinical course of essential thrombocythemia in 147 cases.

The authors retrospectively analyzed the initial characteristics, treatment, and clinical course in 147 patients with essential thrombocythemia (ET). Median age was 60 years and the M:F ratio was 0.69. At diagnosis, 53 patients were asymptomatic; 50 patients had functional symptoms (mainly vasomotor disturbances); 27 patients had large vessel thrombosis; 27 patients had a bleeding diathesis; and seven patients had both bleeding and thrombosis. The platelet count ranged from 0.7 to 2.92 X 10(12)/l. Forty-five of the 61 tested patients (61%) had prolonged bleeding time and/or platelet hypoaggregation. Three patients had in vitro spontaneous aggregation. No significant correlations were found between hemostatic findings and in vivo bleeding or thrombosis. The incidence of bleeding, however, was higher in patients with more than 2 x 10(12)/l platelets. Of 87 karyotypes performed with banding techniques, only four were abnormal. One hundred twenty-nine patients received one or more cytoreductive agents at diagnosis or during follow-up. Sixty patients received an antiaggregating agent. First-line therapy was radiophosphorus (32P) in 22 patients; busulfan in 35 patients; and hydroxyurea in 72 patients. Hydroxyurea required continuous maintenance therapy and had to be changed to another treatment in 12 of the initial responders because of inadequate control of thrombocythemia. During follow-up, 14 treated patients experienced one or several major thrombotic events. Two untreated patients also had major thrombosis. Only one major bleeding event was seen during follow-up. Median actuarial survival was 73.5% at 7 years and only one patient progressed to acute non-lymphocytic leukemia (ANLL). These results suggest that large vessel thrombosis is the main complication of ET. It appears largely unpredictable in a given patient at diagnosis but can be largely prevented by the control of thrombocythemia. Because of the low incidence of side effects of treatment in this experience, the authors believe that cytoreductive therapy is indicated in most patients with ET, as long as a group of patients with very low risk of thrombosis is not defined in prospective studies.

Adolescent↗
PubMed1990

Comparison of distraction epiphyseolysis and partial metaphyseal corticotomy in leg lengthening.

We have used Ilazorov's method of distraction epiphyseolysis for leg lengthening since 1977 and his new method of corticotomy or compactotomy since 1983. The first method was carried out in 22 lower limbs with an average lengthening of 8.25 cm (range 4 to 18 cm); included in this group are 2 patients with achondroplasia in whom both legs were lengthened 12 cm. In the second method, a corticotomy is carried out at the metaphyseal-diaphyseal junction followed by distraction in Ilazorov's apparatus (4 x 0.25 mm a day). We lengthened 30 legs; included are 5 patients who had both legs lengthened from between 8 and 12 cm. In the remainder an average of 7.9 cm of lengthening was achieved (range from 4 to 15 cm). The index for the treatment time per cm achieved (time from operation until full weight-bearing per cm of lengthening) was shorter after distraction epiphyseolysis than after corticotomy. Complications were also a little less after the latter procedure. Distraction epiphyseolysis has to be limited to children from aged 12 years until growth ceases. The advantage with corticotomy is that it can be done at any age from 5 to 30 years. Care is needed in both cases to avoid complications.

Adolescent↗
PubMed1990

The MSS51 gene product is required for the translation of the COX1 mRNA in yeast mitochondria.

The MSS51 gene product has been previously shown to be involved in the splicing of the mitochondrial pre-mRNA of cytochrome oxidase subunit I (COX1). We show here that it is specifically required for the translation of the COX1 mRNA. Furthermore, the paromocyin-resistance mutation (P454R) which affects the 15S mitoribosomal RNA, interferes, directly or indirectly, with the action of the MSS51 gene product. Possible roles of the MSS51 protein on the excision of COX1 introns are discussed.

Alleles↗
PubMed1990

Correction of clubfoot relapse using Ilizarov's apparatus in children 8-15 years old.

Treatment of relapsed or neglected clubfeet between the age of 8-15 years is at present unsatisfactory. Correction by triple arthrodesis with wedge osteotomies is not possible before the end of skeletal maturation. This caused us to use Ilizarov's external fixator, which made it possible to correct all components of clubfoot simultaneously by continuous guided distraction. Thirteen feet in 12 children were treated. A plantigrade foot was achieved in all cases. All patients were able to wear ready-made shoes. Complications were some slight and two severe pin track infections, temporary edema, and two relapses successfully treated by means of second procedures.

Adolescent↗
PubMed1990

Slow infusions of vinblastine in the treatment of adult idiopathic thrombocytopenic purpura: a report on 43 cases.

Forty-three adult patients with idiopathic thrombocytopenic purpura (ITP) were treated by slow intravenous infusions of vinblastine. Nineteen had ITP of recent onset (i.e. of less than 6 months duration) and had contraindication to steroids (3 patients), refractoriness to steroids (6 patients) or to steroids and high dose intravenous immunoglobulins (IVIg, 10 patients). Of the 19 patients, 10 achieved complete response (CR), 2 achieved partial response (PR), 2 had minor response (MR) and the remaining 5 patients had no response (NR). Six of the complete responders remained in CR after 12 to 48 months, whereas all other responders relapsed within 3 months, in spite of maintenance therapy. Twenty-four patients had chronic ITP (i.e. of 6 months duration or more) and had showed no or only transient response to steroids and/or splenectomy, and in many of them, to other therapeutic approaches. Four achieved CR, 4 PR, 6 MR and 10 NR. All but 3 responses were shorter than 3 months, in spite of maintenance therapy. Most responses to slow infusions of vinblastine began after the first infusion. Main side effects included leukopenia in 9 patients (but with absolute neutropenia in only one) and peripheral neuropathy in 2 patients. Interval from diagnosis was the only prognostic factor of response to treatment. We conclude that slow infusions of vinblastine may be a useful approach in ITP of recent onset, when contraindication or refractoriness to steroids and/or IVIg exists. In our experience, this treatment has limited benefit in chronic ITP. In addition, it remains to be demonstrated that slow infusions of vinca alkaloids have any superiority over intravenous bolus injections of the same drugs.

Adult↗
PubMed1990

Phase II study of deoxydoxorubicin in previously untreated metastatic breast cancer.

With the objective of identifying new chemotherapeutic agents active against breast cancer, we administered the phase II agent deoxydoxorubicin (DxDx) to 25 patients who had received no prior chemotherapy for their metastatic breast cancer. A dose of 30-35 mg/M2 given at 3 week intervals resulted in a response rate of 12%. The patients were subsequently treated with a combination of 5-fluorouracil, methotrexate, vincristine, cyclophosphamide, and prednisone. A response rate of 38% was achieved with this combination as second line therapy. Toxicity of DxDx was predominantly hematopoietic. One patient developed congestive heart failure. Median survival from onset of treatment with DxDx was 39 weeks. DxDx appears to be minimally active against metastatic breast cancer. Whether the administration of phase II agents as first line therapy offers an advantage in the overall management of metastatic cancer, needs further evaluation.

Adult↗
PubMed1990

Polychlorinated dibenzo-p-dioxins and dibenzofurans in marine mammals in the Canadian North.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in pooled samples of ringed seal (Phoca hispida) blubber, beluga (Delphinapterus leucas) blubber and polar bear (Ursus maritimus) liver and fat from several areas throughout the Canadian north and compared to mean PCB and HCB levels in the same samples. All seal samples, and all but one polar bear sample, had detectable 2,3,7,8-TCDD at concentrations ranging from 2 to 37 ng/kg, but TCDD was not found in beluga blubber (< 2 ng/kg). All seal samples and one of three beluga samples contained 2,3,7,8-TCDF at levels of 2 to 7 ng/kg, but TCDF was not found in any bear sample. TCDF must therefore be cleared rapidly by polar bears. No other PCDF congeners were found at detection limits of 4 to 8 ng/kg. OCDD concentrations in seal blubber and polar bear samples ranged from not detected (< 8 ng/kg) to 43 ng/kg. No apparent biomagnification of TCDD, OCDD or TCDF occurred from seal to bear fat, similar to previous findings for DDT, and unlike SigmaPCBs and HCB which biomagnified 6- to 17-fold. Highest concentrations of 2,3,7,8-TCDD and OCDD in seals and bears were found in the central Canadian Arctic Archipelago, and lowest were found in Hudson Bay, the reverse of PCB concentration distribution. The reason for higher levels of TCDD and OCDD in the Arctic than in the sub-Arctic is suggested to be trans-polar movement of aerosols with combustion-related origins in Eurasia. Levels of 2,3,7,8-TCDF were more evenly distributed throughout the North, and were positively correlated with PCB, but not with HCB or 2,3,7,8-TCDD levels in seals.

Journal Article↗
PubMed1990

Glycolipid storage material in Fabry's disease: a study by electron microscopy, freeze-fracture, and digital image analysis.

The glycolipid storage material in Fabry's disease was studied by electron microscopy of thin-sectioned (TS) and freeze-fractured (FF) specimens. In the kidney all deposits were found to be located in lysosomes, arranged as lamellar stacks. Deposits in the heart consisted of intracytoplasmic concentric whirls or folded lamellar structures. High resolution TS micrographs disclosed various defects in the lamellar structure. For stabilization, such defects require additional amphiphilic, surface-active molecules. These molecules could interact with other cellular constituents. The lamellar periodicity of the deposits in FF specimens was determined by reconstruction of the three-dimensional fracture face by digital image analysis. Homogeneous multilamellar deposits exhibited a periodicity of 14-15 nm, contrasting with the conventional estimates of 4-5 nm on TS micrographs. This difference is explained by better preservation of the physiologic hydrated state in FF specimens, with 1 vol of lipids binding 2 vol of water. Inhomogeneous structures with an even higher state of hydration included water lenses between the sheets. The strong hydration obviously contributes to the enlargement of the intracellular glycolipid deposits.

Adult↗
PubMed1990

Immunopathological aspects of etretinate therapy in lichen planus.

Biopsy specimens of involved and uninvolved skin were studied in 8 patients suffering from generalized lichen planus (LP) before and after successful etretinate treatment using murine monoclonal antibodies against several cell surface markers of effector and/or accessory cells of the immune system. In contrast to untreated LP-lesions, in biopsies obtained after etretinate therapy from healed involved skin a markedly disintegrated HLA-DR expression on keratinocytes and intraepidermal Langerhans cells and a nearly total loss of suppressor/cytotoxic T lymphocytes at the dermo-epidermal interface were found. Our data emphasize the key position of the class II antigen expression on various immunocompetent cells, as a marker for a cell-mediated immune reaction, on the other hand, stress the involvement of keratinocytes, Langerhans cells and suppressor/cytotoxic T lymphocytes in the pathogenesis of LP.

Adolescent↗
PubMed1990

The epitope(s) recognized by HNK-1 antibody and IgM paraprotein in neuropathy is present on several N-linked oligosaccharide structures on human P0 and myelin-associated glycoprotein.

The mouse monoclonal antibody HNK-1 and the human monoclonal IgM antibody present in patients with polyneuropathy both recognize carbohydrate epitope(s) on human myelin-associated glycoprotein and P0. In the present study, the oligosaccharide structures that bear the antibody epitope(s) were investigated. The extracellular derivative of myelin-associated glycoprotein (dMAG) was purified by immunoaffinity chromatography. P0 was electroeluted from gel slices. Western blot analysis of whole glycoproteins demonstrated that the epitopes for HNK-1 and the human monoclonal IgM antibody were different. The glycopeptides obtained by proteolysis of purified dMAG and P0 were separated and characterized by affinity chromatography on concanavalin A-Sepharose. Both dMAG and P0 displayed heterogeneity in their oligosaccharide structures, i.e., they both contained mainly tri- and tetraantennary oligosaccharides (approximately 80%), although biantennary (10%) and high-mannose and/or hybrid (10%) oligosaccharides were present. The human monoclonal IgM antibody epitope was present on all types of isolated oligosaccharide structures from either dMAG and P0. The HNK-1 epitope was present on all types of oligosaccharide structures of dMAG, whereas it was present only on tri- and tetraantennary structures of P0.

Antibodies, Monoclonal↗
PubMed1990

Chemotactic control of the two flagellar systems of Vibrio parahaemolyticus.

Vibrio parahaemolyticus synthesizes two distinct flagellar organelles, the polar flagellum (Fla), which propels the bacterium in a liquid environment (swimming), and the lateral flagella (Laf), which are responsible for movement over surfaces (swarming). Chemotactic control of each of these flagellar systems was evaluated separately by analyzing the behavioral responses of strains defective in either motility system, i.e., Fla+ Laf- (swimming only) or Fla- Laf+ (swarming only) mutants. Capillary assays, modified by using viscous solutions to measure swarming motility, were used to quantitate chemotaxis by the Fla+ Laf- or Fla- Laf+ mutants. The behavior of the mutants was very similar with respect to the attractant compounds and the concentrations which elicited responses. The effect of chemotaxis gene defects on the operation of the two flagellar systems was also examined. A locus previously shown to encode functions required for chemotactic control of the polar flagellum was cloned and mutated by transposon Tn5 insertion in Escherichia coli, and the defects in this locus, che-4 and che-5, were then transferred to the Fla+ Laf- or Fla- Laf+ strains of V. parahaemolyticus. Introduction of the che mutations into these strains prevented chemotaxis into capillary tubes and greatly diminished movement of bacteria over the surface of agar media or through semisolid media. We conclude that the two flagellar organelles, which consist of independent motor-propeller structures, are directed by a common chemosensory control system.

Chemotaxis↗
PubMed1990

Developmental regulation of expression of the lactate dehydrogenase (LDH) multigene family during mouse spermatogenesis.

Expression of the Lactate Dehydrogenase (LDH) genes during various stages of spermatogenesis was studied by using a combination of Northern blot analyses and in situ hybridization techniques. These studies have indicated that developmentally programmed expression of all three functional LDH genes occurs during differentiation of germ cells. The LDH/C (ldh-3) gene was expressed exclusively during meiosis and spermiogenesis, beginning in leptotene/zygotene spermatocytes and continuing through to the elongated spermatids. LDH/C (ldh-3) gene expression was accompanied by transient expression of the LDH/A (ldh-1) gene in pachytene spermatocytes and round spermatids. The LDH/B (ldh-2) gene was expressed mainly in Sertoli and spermatogonial cells. By using somatic cell hybrids, the LDH/C (ldh-3) gene has been mapped to mouse chromosome 7, establishing that it is syntenic with the LDH/A (ldh-1) gene locus. Experimental observations made in this study provide new insight into the order and sequence of events involved in the regulation of gene expression of the LDH gene family during spermatogenesis.

Animals↗
PubMed1990

[Paraneoplastic Bazex acrokeratosis--disease course in palliative therapy of cancer of the base of the tongue].

A 62-year old quarryman developed distinct, erythematosquamous and keratotic lesions associated with subungual hyperkeratosis and nail detachment on all fingertips within 9 months. Subsequently, scaly erythema of the nose and of the auricles appeared. Clinically paraneoplastic acrokeratosis Bazex (APB) was diagnosed. Thorough endoscopic examination revealed an asymptomatic squamous cell carcinoma at the base of the tongue, which had already metastasized to the regional lymph nodes. Impressive regression of most of the relevant skin symptoms occurred during combined neck dissection and radiotherapy. A survey of recent reports on APB in the literature is given.

Acrodermatitis↗