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Biomedical subjects

J Y Borg

Publications and source records attributed to J Y Borg.

At least 55 records · Page 3Linked to original sources
PubMed1993

Acquired von Willebrand's syndrome associated with decrease of plasminogen activator and its inhibitor during hypothyroidism.

OBJECTIVES: In a prospective study we searched for von Willebrand's syndrome during hypothyroidism and investigated the effects of treatment with thyroid hormones on plasma concentrations or activities of the factors involved in von Willebrand's disease in addition to tissue plasminogen activator and plasminogen activator inhibitor 1. METHODS: Eleven patients with hypothyroidism were tested. Factor VIII coagulant activity (VIIIc), von Willebrand factor (vWf:Ag), von Willebrand factor activity (vWf:RCo), tissue plasminogen activator antigen (tPA) and plasminogen activator inhibitor activity (PAI) was monitored before and after correction of hypothyroidism by hormone supplementation. RESULTS: Five patients had laboratory evidence of type I von Willebrand's disease. The other six patients had concentrations or activities of the factors involved in von Willebrand's disease within the normal range. In all cases except one, during thyroxin treatment, von Willebrand factors returned to normal if initially low, or increased clearly if initially normal. With the correction of hypothyroidism, an increase of tPA was noted in the eleven patients, associated with a significant increase of PAI. CONCLUSION: Laboratory evidence of von Willebrand's disease is common during hypothyroidism. Study of plasminogen activator and its inhibitor suggest a decrease of von Willebrand factor synthesis during hypothyroidism.

Adult↗
PubMed1993

Potent activity of peripheral blood lymphocytes in inducing hepatocyte stimulating factor and urokinase in monocytes.

As fibrinogen is an independent risk factor for arterial thrombosis we were interested in analysing the mechanism controlling fibrinogen biosynthesis. In this work, we showed that incubation of monocytes with lymphocytes increased hepatocyte stimulating factor (HSF) production. Different mechanisms are involved and our results demonstrated that this effect is in part mediated by an increase in interleukin 6 (IL-6) production. However, IL-6 cannot account for the whole effect and other cytokines could be implicated. In addition, we observed a stimulation of urokinase-type plasminogen activator (u-PA) associated with monocytes when these cells were incubated with lymphocytes for 18 h at 37 degrees C. By producing fragment D (fibrinogen degradation product) and D-dimer (fibrin degradation product) this fibrinolytic activity might also contribute to fibrinogen biosynthesis by hepatocytes.

Cells, Cultured↗
PubMed1992

[Prevalence and description of cardiac involvements in primary antiphospholipid syndrome].

In order to assess the prevalence of cardiac involvement in the primary antiphospholipid syndrome (PAS), a syndrome which associates thromboembolism, recurrent abortion, the presence of antiphospholipid antibodies and thrombocytopenia, transthoracic (TTE) and trans-esophageal echocardiography (TEE) was performed in 15 patients, 10 women and 5 men with a mean age of 38.8 +/- 11 years, with the PAS but without systemic lupus erythematosus. The presentation of the PAS was a thrombotic event (6 arterial and 7 venous) in 13 cases, and recurrent abortion in 3 cases. Twelve patients had high anticardiolipin antibody levels (> or = 15 U GPL) and 12 had a raised anti-prothrombinase antibody title. Valvular heart disease was detected in 9 patients (60%) as a valve thickening (> or = 5 mm for the mitral and > or = 3 mm for the aortic valve) or nodule. Mitral regurgitation was observed in 4 cases both on TTE and TEE and was mild in 3 cases and severe in 1 case. Aortic regurgitation was diagnosed in 6 patients, in 3 cases by TTE and in 6 cases by TEE. It was mild in 5 cases and moderate in the other cases. Pericardial effusion was observed in 3 patients (20%), alone in 1 case and associated with valvular disease in the other two cases. No abnormality of left ventricular systolic or diastolic function could be demonstrated. In conclusion, cardiac involvement seems to be common in the PAS, and TEE is a sensitive and accurate method for describing the valvular, especially aortic valve, abnormalities.

Abortion, Habitual↗
PubMed1992

[Syndromes of venous mesenteric ischemia: infarction and transient ischemia].

The reports of 8 patients with acute or subacute abdominal pain related to venous mesenteric ischemia were reviewed. None of the patients presented local or regional predisposing factors for venous thrombosis. In 4 patients, a localized segment of ischemic small bowel (median length 125 cm; range: 30-350) was resected without immediate anastomosis and postoperative anticoagulation therapy was given. Two of these patients developed recurrent ischemia involving the bowel adjacent to the stoma, treated successfully in 1 case by a repeat resection. The 4 other patients hospitalized with intestinal obstructive symptoms (1 case) or abdominal angina (3 cases) were treated by long term anticoagulation in 3 cases and artificial nutrition in 2 cases. None of them developed mesenteric infarction with a median follow up of 34 months. In 7 of the 8 patients, a coagulopathy was found: primary myeloproliferative disorder (1 case), hypercoagulation state (5 cases), autoimmune hemolytic anemia (1 case). These observations suggest that venous mesenteric ischemia included two different entities on the basis of clinical and morphological criteria: mesenteric infarction and subacute transient ischemia without bowel infarction. Most of apparently idiopathic cases of acute or subacute venous mesenteric ischemia are related to hypercoagulation states requiring a long term anticoagulation.

Abdominal Pain↗
PubMed1992

[Acute thrombosis of the right renal vein. Two cases with coagulopathies].

We report two cases of renal vein thrombosis, unusual because of acute expression, right renal vein localization, absence of the usual renal or perirenal causes, surgical management and a never before reported etiology. In one case the thrombosis was secondary to primary antiphospholipid syndrome, in the other it was secondary to heparin associated thrombocythemia. In this case surgical management was performed during prostacyclin infusion.

Acute Disease↗
PubMed1992

[Horton's disease with involvement of the arterial trunks of the arms. Pathogenic role of anticardiolipin antibodies? Report of two cases].

Diffuse arterial involvement in temporal arteritis is well known but the intimate mechanisms of vasculopathy is unknown. Recently the presence of anticardiolipin antibodies (aCL) has been recognized in giant cell arteritis. We report two cases of temporal arteritis with diffuse arterial involvement associated with aCL (axillary arteries in the two cases associated with femoral arteries in one). During corticosteroid and anticoagulant therapy, a rapid improvement was noted with regression of upper-limb ischemia. One month later, the aCL were absent. These cases confirm the presence of aCL in giant cell arteritis with diffuse arterial involvement. These antibodies might imply severe vascular damage and could play a role in pathogenesis of the vasculopathy of temporal arteritis. Their presence suggests the necessity of anticoagulant therapy at the beginning of corticosteroid therapy.

Adrenal Cortex Hormones↗
PubMed1991

[Influence of protein S deficiency on the arterial thrombosis risk].

Protein S is the cofactor of activated protein C which, together with the antithrombin system, is a major regulator of coagulation. Congenital protein S deficiency is an important risk factor for venous thrombosis. In this study of 105 patients with protein S deficiency, 64 had one of several thromboembolic accidents, including 14 arterial thrombotic accidents involving the central nervous system or the myocardium. These accidents occurred in young subjects (mean age: 25 +/- 13 years) only one-third of whom had another risk factor. This high frequency of arterial thrombosis associated with protein S deficiency calls for a prospective study in young subject with cerebral vascular accident or myocardial infarction.

Adolescent↗
PubMed1991

Functional antithrombin-III variant (41 Pro----Leu) identified by liquid secondary ion mass spectrometry.

A genetic variant of antithrombin with impaired heparin cofactor activity was identified in 4 members of a French family. Both the variant and normal antithrombin component were purified by affinity chromatography on heparin Sepharose. Reverse phase peptide mapping revealed a single altered peak when tryptic digests of both antithrombins were compared. After further purification of the aberrant peptide, amino acid analysis indicated a substitution of 41 Leu----Pro (antithrombin Basel). This result was confirmed by liquid secondary ion mass spectrometry which gave a measured mass of 816.4655 Da for the new peptide compared to a calculated mass of 800.3579 Da for the normal peptide and 816.4579 for the Leu----Pro substitution.

Adult↗
PubMed1990

Antithrombin Rouen-IV 24 Arg----Cys. The amino-terminal contribution to heparin binding.

A variant antithrombin with reduced heparin affinity was shown by mass spectrometry sequencing and DNA amplification to have a substitution of a cysteine for an arginine at residue 24. The position of Arg-24 can be fixed within a 12 A radius from the bridge at Cys-21. This is compatible with findings in the homologous protease nexin-1 which indicate an extension of the binding site of heparin from the D-helix to under the adjacent amino-terminal pole.

Adult↗
PubMed1989

Protein C: Rouen, a new hereditary protein C abnormality with low anticoagulant but normal amidolytic activities.

A family is described in which venous thrombo-embolic disease is associated with reduced plasma protein C anticoagulant activity but normal levels of protein C amidolytic activity and antigen. The partial characterization of the heterozygous defect is described using crossed immunoelectrophoresis (CIE) with or without calcium and seven functional assays which differ by activators (thrombin-thrombomodulin complex, bovine thrombin and Protac snake venom) and by an eventual preliminary adsorption on insoluble salts. PC activity was thereafter determined either by chronometric or amidolytic assays. The results indicate that this abnormal protein C (PC) is normally activated and at least partially carboxylated. Three hypothesis are proposed to explain the discrepancy between normal amidolytic and low anticoagulant activities.

Adult↗
PubMed1988

New carbohydrate site in mutant antithrombin (7 Ile----Asn) with decreased heparin affinity.

A mutant antithrombin was isolated from the plasma of a patient with pulmonary embolism. The new protein, which accounted for 55% of the antithrombin, had decreased heparin affinity and contained two components when analysed on the basis of either charge or molecular mass. Sialidase and endo-beta-N-acetylglucosaminidase F treatment suggested that this heterogeneity was due to a partial glycosylation occurring at a new carbohydrate attachment sequence. Peptide mapping by reverse-phase HPLC showed that the abnormality involved the N-terminal tryptic peptide. Sequence analysis demonstrated that the underlying mutation was 7 Ile----Asn which introduces a new Asn-Cys-Thr glycosylation sequence. This new oligosaccharide attachment site occupies the base of the proposed heparin-binding site, and the finding explains the consequent decrease in heparin affinity.

Antithrombin III↗
PubMed1988

Proposed heparin binding site in antithrombin based on arginine 47. A new variant Rouen-II, 47 Arg to Ser.

Antithrombin Rouen-II, a new inherited variant of antithrombin-III, was found in two members of a family with no definite history of thrombosis. The subjects had normal antigenic concentrations of antithrombin and normal progressive inhibitory activity. However, the variant had defective heparin and heparan sulfate cofactor activities, and was not activated by a synthetic pentasaccharide representing the minimum heparin sequence. The abnormal antithrombin was isolated using heparin-Sepharose chromatography, and on electrophoresis at pH 8.6 migrated more anodally than normal. Two-dimensional peptide mapping of tryptic and Staphylococcus aureus V8 protease digests was performed and the abnormal peptide was located by tryptophan staining. Amino acid sequence studies demonstrated a substitution of arginine at residue 47 by a serine. Evidence strongly suggests that arginine 47 is a prime heparin binding site in antithrombin and that it forms part of a proposed positively charged linear site (to which heparin binds) that stretches across the surface of the molecule from the A to the D helix.

Adult↗
PubMed1987

Heparin binding defect in a new antithrombin III variant: Rouen, 47 Arg to His.

Antithrombin III (AT-III) Rouen is a hereditary abnormal antithrombin with normal progressive inhibitory activity and reduced heparin cofactor activity. It was isolated from the plasma of a woman who suffered a sudden idiopathic sensorineural hearing loss and balance impairment. There was no familial history of thrombosis. By heparin-Sepharose chromatography, AT-III Rouen was separated from the normal antithrombin on elution with increasing concentrations of NaCl. AT-III Rouen eluted earlier than is normal at both pH 7.4 and pH 6.0. At the lower pH, the antithrombins bound more avidly to the column, with the abnormal AT-III eluting closer to the normal than at the higher pH. Two-dimensional peptide mapping of tryptic and Staphylococcus aureus V8 protease digests of carboxymethylated antithrombins was performed on thin-layer silica plates. The abnormal peptide was located by tryptophan staining, and amino acid analysis and sequence studies demonstrated a substitution of an arginine at residue 47 for a histidine. Results from this study suggest that replacement of arginine 47 by a partially positively charged histidine has less effect on the heparin binding affinity than dose replacing it with a neutral cysteine side chain as in AT-III Toyama, in which no heparin binding was observed. In addition, heparin binding per se is not a sufficient condition to activate AT-III.

Adult↗