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Biomedical subjects

G Tobelem

Publications and source records attributed to G Tobelem.

At least 91 records · Page 5Linked to original sources
PubMed1988

[New treatments for Raynaud's syndrome].

Raynaud's phenomenon, either idiopathic or secondary is often severe. It is due to a vasospasm in response to cold, and an increase in sympathetic tone, hyperviscosity and sometimes hyperactivation of platelets and erythrocytes have been reported. New drugs have been developed such as ketanserin, which is a specific inhibitor of serotonin S2 receptors, and has led to a positive response in 38%-80% of patients. The prostaglandins PGE1 and PGI2 were given i.v. in refractory patients and led to a beneficial effect in 50%-70% of cases. These data seem to justify the development of prostaglandin analogues.

Alprostadil↗
PubMed1988

[Priapism after cavernography. Report of an original case].

The authors report a case of priapism following cavernography with secondary fibrosis of the corpora cavernosa demonstrated histologically. They stress the importance of a rigorous cavernography technique which must take account of the respective tissue toxicity of the various contrast media used.

Adult↗
PubMed1988

[A study of hematology questions on the competitive examination of medical residents 1984, 1985 and 1986].

The recently (1984) introduced new modalities for selecting the residents in France is based upon multiple choice (MCQ) questions (2/3) and written answers to patients managements problems (PMP) (1/3). MCQ and PMP are selected by a group for 8 hematologists from the 42 French schools of medicine. The process of selecting the questions, the major topics explored by these questions, the docimological quality of the questions and the most surprising errors made by the candidates are studied. Results argue for a sustained effort in order to improve the teaching of the basis of hematology in our country.

Educational Measurement↗
PubMed1987

Heparin degradation in the endothelial cells.

We analyzed the molecular weight distribution of (125I) heparin fractions bound or internalized by human endothelial cells, using gel permeation chromatography. Our results showed that high molecular weight heparin chains are selectively bound and internalized by endothelial cells. Endocytosis is followed by depolymerization of internalized heparin. Chloroquine prevented depolymerization of internalized heparin, indicating that lysosomal enzymes are involved in this process. Degradation of high molecular weight heparin chains by endothelial cells may contribute to the inactivation of the drug, especially as concerns the antifactor IIa activity.

Biological Transport, Active↗
PubMed1987

Selective binding of heparins to human endothelial cells. Implications for pharmacokinetics.

Cultured endothelial cells isolated from human umbilical vein bind heparin and heparin fragments. The binding capacity of endothelial cells for 35S-heparin was for 38% composed of high affinity binding sites (Kd = 11 X 10(-8) M) and for 62% of sites with much lower affinity (Kd = 14 X 10(-7) M). The affinity of unlabeled compounds for heparin binding sites was determined by competition with binding of 125I-heparin. I50 found for unlabeled heparin was 16 X 10(-8) M, which is in agreement with the Kd for binding of heparin to high affinity sites. PK 10169, a low molecular weight fragment of heparin, competed only at relatively high concentrations (I50 = 10(-5) M). Competition experiments with subfractions of PK 10169 showed that I50 was inversely correlated with molecular weight. Gelfiltration of 35S-heparin and 35S-PK 10169 before and after binding to endothelial cells demonstrated a selective binding of high molecular weight molecules from polydisperse heparin and PK 10169 preparations. Bound heparin and PK 10169 molecules were detached from the cell-surface by proteolytic treatment and tested for antifactor-Xa and antifactor-IIa activity. Released heparin is slightly more active in antifactor-Xa and antifactor-IIa activity than its parent preparation. Released PK 10169 was 4 fold more active in antifactor-Xa and 8 fold more active in antifactor-IIa assays than heparin.

Binding Sites↗
PubMed1987

The lupus anticoagulant and its role in thrombosis.

The lupus anticoagulant is usually found in the plasma of patients with systemic lupus erythematosus. Lupus anticoagulants are antibodies to phospholipids and probably to phosphodiester-linked phosphate groups. A high frequency of thrombotic events in patients with lupus anticoagulant has been reported. Nevertheless the pathogenesis of thrombosis in these patients remains unknown. Endothelium which plays a key role in the antithrombogenic-thrombogenic balance could be a target for the lupus anticoagulant and alterations of some endothelial-cell functions could be responsible for the thrombotic events. The effects of the lupus anticoagulant on the phospholipids of the protein C-thrombomodulin complex may be important although evidence of such a reaction in vivo is awaited.

Autoantibodies↗
PubMed1987

Platelet acquired defect in PDGF and beta thromboglobulin content in hairy cell leukaemia: improvement after interferon therapy.

To investigate the platelet contribution to the development of myelofibrosis in hairy cell leukaemia (HCL), we have studied two platelet alpha granule components in 15 patients with HCL before chemotherapy: mitogenic activity was measured by 3H thymidine incorporation in BALB/C 3T3 cells and beta thromboglobulin (beta TG) assayed by radioimmunoassay (RIA). Platelet mitogenic activity and beta TG content were significantly decreased in the patients as compared to the control subjects. The nine patients who were treated with recombinant human interferon (IFN alpha A) were restudied after 4 months of therapy. The levels of both mitogenic activity and beta TG platelet content were significantly increased after IFN alpha-treatment with a complete response in five of the nine treated patients, a partial response in two and no response in the two others. HCL seemed therefore to be responsible for an acquired platelet alpha granule defect. As in the grey platelet syndrome a relationship between this abnormal platelet granule storage and the development of myelofibrosis is suggested in HCL.

Blood Platelets↗
PubMed1987

[Angiogenic factors].

Angiogenesis is an important step in tumor growth. From tumor angiogenic factor (TAF) to angiogenin, 14 years of research led to purification, sequencing and cloning of a strong tumor angiogenic factor. Tumor angiogenesis can be inhibited by a cartilage factor, by protamine or by heparin plus cortisone. Heparin by its interactions with the growth factor has an interesting pharmacological role in the angiogenesis phenomenon. Its effect on the growth of vascular cells (endothelial cells, smooth muscle cells, fibroblasts) seems promising.

Angiogenesis Inducing Agents↗
PubMed1987

[The value of echography in scrotal contusions. Personal experience apropos of 20 cases].

We report a serial case study of 20 patients presenting scrotal contusions and for whom an emergency scrotal ultrasonography was performed. This investigation is not a luxury. It was a useful confirmation diagnostic tool for hematocele in 1/3 of cases (7/20) as well as for the detection of associated epididymal and or testicular lesions. In 2/3 of cases (13/20) it detected lesions unsuspected by clinical examination so that a therapeutic decision was taken promptly. Scrotal echography is therefore a useful emergency tool not for major trauma where the surgical decision is evident, but for apparently benign trauma where the clinical examination is currently deficient and needs provided a trained ultrasonography operator is available.

Adult↗
PubMed1987

[Effects of chemical and radiographic factors on the treatment of renal lithiasis using extracorporeal external shock-wave lithotripsy].

The systematic collection and filtration of urine for three days after extracorporeal shock wave lithotripsy (ECSWL) has enabled the chemical analysis of the stones treated in 90% of cases. We have been able to demonstrate a correlation between the chemical nature and the mode of fragmentation of the stones. Calcium oxalate monohydrate, brushite and cystine stones form fairly large, well separated, angular fragments with sharp edges. Calcium oxalate dihydrate, calcium phosphate and magnesium ammonium-phosphate (struvite) stones are reduced to an amorphous dust. These findings have direct therapeutic implications, as it is absolutely essential to make sure that no large stone fragments are left in the urinary tract after lithotripsy. These elements led us to try to evaluate the chemical nature and the hardness of the stones on the basis of the radiological findings, in order to adopt the best possible therapeutic strategy. Calcium oxalate dihydrate stones have a striated, spiky and non-homogeneous appearance on plain X-rays. They are frequently responsible for filling defects on intravenous pyelography. They are friable stones which are easily fragmented. In contrast, calcium oxalate monohydrate stones present a regular homogeneous opacity on plain X-rays with no filling defect on intravenous pyelography. These stones are hard and are broken up, with difficulty, into large fragments on the initial fluoroscopic images at the start of treatment. Many stones have a mixed composition (calcium oxalate monohydrate, calcium oxalate dihydrate and calcium phosphates): the plain X-ray does not provide sufficient information and the presence of a filling defect on intravenous pyelography may or may not be suggestive of a friable stone.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium Oxalate↗
PubMed1987

[Mycobacterium xenopi infection in emphysematous bulla. Apropos of 4 cases operated on].

The authors presented their observations of four patients who were operated on for a supra-infection of emphysematous bullae by Mycobacterium xenopi. In two cases the patients were operated on without a diagnosis and excision of the right upper lobe assured their cure. The other patient underwent a decortication and ultimately relapsed. The fourth had a bilateral apical infection and underwent bilateral excision. A survey of the literature leads one to think that pulmonary infections with a Mycobacterium xenopi occur in emphysematous bullae more often than is generally thought. The unreliability of the results of antituberculous drugs, the complications of treatment and the risks of recurrence after treatment are well known. Controlled surgical excision of the lesions, which is most often followed by a definitive cure, always merits consideration as part of the therapeutic arsenal.

Adult↗
PubMed1987

[Problems posed by etiologic research on thrombotic conditions].

In venous thrombosis conditions, the biological etiological survey is, to day, absolutely necessary. In approximately 30 p. cent of the cases of recurring venous thrombosis, there is a deficit in Protein S, Protein C, antithrombin III, a plasminogen or fibrinogen abnormality and a lack of fibrinolysis. On the contrary, despite of the obvious role of platelets in arterial thrombosis, the biological survey is more difficult.

Arteries↗
PubMed1987

[From heparin to heparins: toward new therapeutic perspectives?].

Heparin is mainly known for its anticoagulant action, but today other biological effects are investigated. With the low molecular weight heparin fractions (LMWH), more homogenous, a more detailed study of the mechanism of action of heparins can be made. The anticoagulant action of heparin is mainly antithrombin III (AT III) dependent and the binding site of AT III on the heparin molecule has been recently identified. LMWH have a lower anticoagulant (anti-IIa) activity, and a relatively higher anti-Xa activity (ratio anti-Xa/anti-IIa = 5 to 10 for LMWH and 1 for standard heparin). The antithrombotic action of heparins is not strictly correlated to their anticoagulant activity. Other mechanisms of action, such as interactions with vascular endothelial cells and the fibrinolytic system may contribute to the antithrombotic action of heparins. New therapeutical possibilities are currently under investigation. Inhibition of vascular smooth muscle cells growth by heparin suggest a possible control of the atherosclerotic process by heparin. Moreover, heparin and its derivatives might be involved in the regulation of the cellular growth process.

Blood Platelets↗