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Biomedical subjects

J T Wilde

Publications and source records attributed to J T Wilde.

36 records · Page 2Linked to original sources
PubMed1997

Hepatitis G virus infection in patients with bleeding disorders.

Eighty-two patients with bleeding, disorders registered with our centre were screened for infection with hepatitis G virus (HGV). 80 patients were positive for hepatitis C (HCV) antibodies, 66 of whom (83%) were HCV PCR positive. 11 patients (13%) were HGV RNA-positive, a similar prevalence rate to that of other studies of patients with bleeding disorders who received factor concentrates prior to the introduction of viral inactivation procedures. There was no significant difference in histological activity index (HAI) between the 10 HGV RNA-positive and the 31 HGV RNA-negative patients who underwent liver biopsy for assessment of HCV infection (median HAI scores 5.5, range 2-10 and four, range 0-10 respectively, P = 0.07). One patient in each group had established cirrhosis. In patients who underwent HCV quantitation there was no significant difference in HCV viral titre between HGV RNA-positive and negative patients (median HCV titre in HGV RNA-positive patients 2.10 x 10(5) DNA copies/ml (n = 8) range 4.17 x 10(2) to 4.17 x 10(6), median HCV titre in HGV RNA-negative patients 3.33 x 10(5) (n = 31) range 1.00 x 10(3) to 6.67 x 10(6), P = 0.68). In this study there was no evidence that individuals co-infected with HGV and HCV have more severe liver disease than those infected with HCV alone.

Adult↗
PubMed1997

Prevalence of the factor V Leiden mutation in hepatic and portal vein thrombosis.

BACKGROUND: The factor V Leiden (FVL) mutation has been shown to be the most frequent cause of hereditary thrombophilia. The prevalence of the mutation in patients with Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT) has not been fully elucidated. AIMS: To investigate the association between the FVL mutation and BCS and PVT. PATIENTS: Thirty patients with BCS, 32 patients with PVT, and a control group of 54 patients with liver disorders and no history of thrombosis. METHODS: The factor V gene was analysed for the presence of the FVL mutation by a polymerase chain reaction (PCR) technique. The presence of the mutation was confirmed by DNA sequencing. RESULTS: Seven (23%) patients with BCS, one (3%) patient with PVT, and three (6%) patients in the control group were identified as having the FVL mutation. There of the BCS patients had coexisting hypercoagulable states. The prevalence of the FVL mutation was significantly higher in patients with BCS compared with patients with PVT and controls (p < 0.04). The FVL mutation was the second most common aetiology associated with BCS. CONCLUSION: The FVL mutation is an important factor in the pathogenesis of BCS and screening for the disorder must be included in the investigation of patients presenting with this condition. In contrast, the FVL mutation is not a major predisposing factor in the pathogenesis of PVT.

Adolescent↗
PubMed1997

Priapism in a patient with protein C deficiency.

We present the case of a patient with classical protein C deficiency presenting with acute priapism during warfarinization for thrombophlebitis. Priapism is a well-recognized complication of a number of conditions including sickle cell disease and haematological malignancies, but to our knowledge it has not previously been reported in association with protein C deficiency. This case highlights the potential dangers of initiating oral anticoagulant therapy using conventional loading dose regimens in patients with protein C deficiency.

Acute Disease↗
PubMed1996

A combined management protocol for patients with coagulation disorders infected with hepatitis C virus.

The case notes of 394 adults with bleeding disorders registered at our centre together with those of the 72 patients who had died since 1971 were reviewed. 36/72 deceased patients had evidence of HCV infection. Liver decompensation was present at time of death in six. 274 (70%) of the currently registered patients had received factor concentrate or cryoprecipitate and 174 of these were screened for HCV infection. 76% of tested patients were RIBA positive. 87% of RIBA-positive patients were RT-PCR positive. 50 RIBA-positive patients, including nine who were HIV infected, have undergone percutaneous liver biopsy following appropriate factor infusion with no complication. The biopsy was assessed using a Histological Activity Index (HAI) ranging from 0 to 13. Patients with HAI > or = 6 were offered treatment with interferon. Patients with HAI < 6 were followed up with a view to re-biopsy in 2-3 years to assess progression. The median HAI was 4.5 (range 0-10) with HAI > or = 6 in 13 cases (27%). HAI was not correlated with duration of infection. haemophilia severity. RT-PCR status. HIV status or HCV genotype. Liver biopsy, a safe procedure in our hands, is an important investigation in HCV-infected patients to assess suitability for interferon therapy.

Adult↗
PubMed1995

The investigation of a patient with unexpected venous thrombosis.

Over recent years a number of hereditary and acquired defects of the circulation's natural anticoagulant mechanisms have been characterised and shown to predispose affected individuals to thrombosis. It is important to attempt to diagnose a thrombophilia state in patients with a thrombotic tendency in order to provide appropriate management, especially during at-risk situations, both for themselves and asymptomatic relatives identified through family studies. This review defines the patients who should be investigated for an underlying thrombophilia state and describes the hereditary and acquired disorders which should be screened for within an investigation profile. The recently identified factor V Leiden mutation which appears to be the most common hereditary cause of a thrombotic tendency is described in detail and descriptions of the more established thrombophilia states are included. Although the factor V Leiden mutation accounts for a significant proportion of cases fulfilling the criteria for thrombophilia screening, a predisposing cause for thrombosis remains unidentifiable in a large number of patients making it likely that over the years to come new thrombophilia states will continue to be identified.

Blood Coagulation Disorders↗
PubMed1990

Coagulation disturbances following ascites recirculation.

To investigate the effects of extra-corporeal ascites recirculation on coagulation, several coagulation variables were measured in ascitic return fluid and plasma before, during and after this procedure in 16 patients with diuretic resistant ascites. Small but significant reductions in plasma fibrinogen levels and platelet counts and increases in plasma X-oligomer were observed during and after the procedure compared with before. These findings are consistent with the view that ascites recirculation induces disseminated intravascular coagulation although this would appear to be only mild and of no clinical significance in the majority of patients. Although increased levels of activated factor VII were observed in ascitic fluid indicating activation of the extrinsic pathway of coagulation, a significant increase in plasma activated factor VII during the procedure was not demonstrated. Increased fibrinolytic activity was observed in ascitic fluid due to the presence of tissue plasminogen activator. Increased X-oligomer levels were observed in ascitic fluid indicating that lysis of cross-linked fibrin is also an active process within ascites.

Ascites↗
PubMed1990

Haemostatic problems in acute leukaemia.

Disseminated intravascular coagulation (DIC) is a frequent complication of acute leukaemia, in particular acute promyelocytic leukaemia. Although procoagulant substances released from leukaemic blast cells may induce DIC by activating conventional coagulation pathways, there is increasing evidence to suggest that direct activation of fibrinogen by proteases released from blast cells may be the predominant mechanism by which DIC is initiated. Primary fibrinolysis has also been proposed as the cause of the haemorrhagic diathesis in some cases of acute leukaemia. Although plasminogen activators have been demonstrated in leukaemic blast cells supporting this view, cases of primary fibrinolysis would appear to be rare. A bleeding tendency attributed to primary fibrinolysis may more often be the result of an exaggerated fibrinolytic response secondary to DIC. The main strategies of treatment for leukaemia associated DIC are rapid initiation of chemotherapy and vigorous blood product support until the DIC resolves once the blast cells have been eradicated. The role of heparin in the management of leukaemia associated DIC remains controversial. There is recent evidence to suggest that heparin therapy does reduce the incidence of haemorrhagic death although it has been recommended that relatively low intravenous doses should be administered initially to reduce the risk of heparin induced haemorrhage.

Acute Disease↗
PubMed1990

A comparative evaluation of assays for markers of activated coagulation and/or fibrinolysis: thrombin-antithrombin complex, D-dimer and fibrinogen/fibrin fragment E antigen.

Measurements were made of levels of D-dimer in plasma and serum, thrombin-antithrombin complex (TAT) in plasma and fibrinogen/fibrin fragment E antigen (FgE) in serum in a normal healthy control group and in patients with a range of disorders associated with hypercoagulability. Levels were determined in 31 normal healthy controls, 30 patients with disseminated intravascular coagulation (DIC), 21 patients with deep venous thrombosis (DVT), 27 patients with myocardial infarction (MI), 26 patients with acute leukaemia and 56 patients with liver disease. Considering all subjects, significant correlations were established between the results of all assays. Notably high correlations (r greater than 0.9) were established between plasma and serum levels of D-dimer, between plasma levels of D-dimer and serum levels of FgE, and between serum levels of D-dimer and FgE. All assays showed very high discrimination (sensitivity) between the normal control group and patients with DIC (97-100%), but there were marked differences between the assays in sensitivity for DVT and MI. In general, the FgE assay was more sensitive than the D-dimer assay, whilst both the FgE and D-dimer assays were more sensitive than the TAT assay. The same trends were apparent in the capability of the assays to discriminate between the normal control group and patients with acute leukaemia and liver disease: disorders with an unknown prevalence of activation of coagulation/fibrinolysis. Our results indicated that measurements of fibrinogen/fibrin degradation products (FDPs) in serum were almost unaffected by artefacts. The data further suggested that the broad-spectrum FgE assay was better than the more specific D-dimer assay in detecting clinical hypercoagulability. Our study showed that, in the clinical conditions examined, FDPs were more effective markers of hypercoagulability than TAT.

Acute Disease↗
PubMed1989

Plasma D-dimer levels and their relationship to serum fibrinogen/fibrin degradation products in hypercoagulable states.

Plasma D-dimer was measured and compared with serum fibrinogen/fibrin degradation product levels (FDPs) in patients with disseminated intravascular coagulation (DIC) and other conditions associated with a hypercoagulable state. D-dimer (N less than 200 ng/ml) was elevated in all 43 patients with DIC, in 48 of 59 patients with liver disease, in 22 of 27 patients with acute leukaemia at presentation, in 17 of 23 patients with malignant disease, in 29 of 39 women in the third trimester of a complicated pregnancy, in 17 of 18 patients with deep venous thrombosis and in only four of 27 patients with acute myocardial infarction. There was a significant correlation between plasma D-dimer and serum FDP levels (P less than 0.01) as follows; DIC: r = 0.58, liver disease: r = 0.57, acute leukaemia: r = 0.84, malignancy: r = 0.87. The frequent elevation of D-dimer observed in liver disease, acute leukaemia, malignancy and complicated pregnancy indicates that a hypercoagulable state is a common occurrence in these conditions although in liver disease elevated levels resulting from a failure of normal clearance mechanisms cannot be excluded. The close relationship between D-dimer and FDP levels suggests that serum FDPs predominantly arise from the interaction of plasmin with crosslinked fibrin rather than with fibrinogen in the conditions in which these were compared.

Blood Coagulation Disorders↗
PubMed1988

Fibrinolysis during normal human pregnancy: complex inter-relationships between plasma levels of tissue plasminogen activator and inhibitors and the euglobulin clot lysis time.

Although it has been previously considered that blood fibrinolytic capacity is reduced during pregnancy, this has been disputed. Also the mechanisms underlying any change in fibrinolysis in pregnancy require clarification. We have therefore measured the plasma activity of tissue plasminogen activator (t-PA) and inhibitors (t-PAi) and the concentration of the pregnancy specific inhibitor (PA12) antigen, as well as the euglobulin clot lysis time (ECLT) during normal pregnancy. Plasma concentrations of fibrinogen, plasminogen, fibrin(ogen) degradation products (FDP) and cross-linked products (D-dimer) were also monitored. We confirm a marked reduction of the fibrinolytic activity of the plasma euglobulin fraction from the second trimester, and a parallel reduction in t-PA and increase in t-PAi activities, with rapid return to non-pregnant levels post-partum. In contrast, PAI2, whilst undetectable in non-pregnant control plasma, was already measurable in the first trimester, increased through pregnancy, and remained at a high concentration up to at least 48 h post-partum. Fibrinogen and plasminogen concentrations rose progressively through pregnancy and FDP and D-dimer were frequently detectable in late pregnancy plasma. Changes in the ECLT and plasma t-PA and t-PAi activities in pregnancy cannot therefore be directly related to the concentration of PAI2 antigen. Also, despite the apparent marked reduction in fibrinolytic capacity fibrin(ogen) breakdown products are frequently present in increased plasma concentrations in late pregnancy.

Female↗
PubMed1988

Association between necropsy evidence of disseminated intravascular coagulation and coagulation variables before death in patients in intensive care units.

The necropsy findings in 21 patients on an intensive care unit, on whom coagulation studies had been performed immediately before death, were assessed. Eleven of the patients were retrospectively studied and 10 were reviewed consecutively in a prospective study. Fifteen patients (eight retrospective and seven prospective) had evidence of disseminated intravascular coagulation. Microthrombi were most often found in the lungs and kidneys. The most common abnormal coagulation tests in patients with necropsy evidence of disseminated intravascular coagulation were raised serum concentrations of fibrinogen and fibrin degradation products, prolonged prothrombin time, and reduced platelet counts. Reduced fibrinogen concentrations and a prolonged thrombin time were the least commonly observed abnormalities. There was no difference in either the prevalence or magnitude of abnormality of any particular coagulation variable test result between those patients with evidence of disseminated intravascular coagulation at necropsy and those without.

Adult↗
PubMed1988

Acquired dysfibrinogenaemia masquerading as disseminated intravascular coagulation in acute pancreatitis.

Acquired dysfibrinogenaemia as the cause of coagulation abnormalities occurred in a case of acute pancreatitis. Initial coagulation studies showed a prolonged thrombin time and increased concentrations of serum fibrinogen/fibrin degradation products and plasma D-dimer. Further studies on purified fibrinogen showed evidence of degradation of the C-terminal ends of the A-alpha chains, which, it is suggested, resulted from the action of circulating pancreatic proteases. Fibrin polymerisation was thus shown to be impaired, which explains the prolongation of the thrombin time. There was a temporal relation between increased amylase activities and the prolonged thrombin time, both of which returned to normal three weeks after admission. Acquired dysfibrinogenaemia may be an underrecognized phenomenon in acute pancreatitis and may lead to misinterpretation of coagulation test abnormalities.

Acute Disease↗
PubMed1987

Peripheral blood lymphocyte subpopulations in patients with primary proliferative and secondary polycythaemia.

Peripheral blood lymphocyte subpopulations were measured in 18 patients with primary proliferative polycythaemia and 13 patients with secondary polycythaemia. A decrease in numbers of suppressor T lymphocytes and an increase in the helper:suppressor T lymphocyte ratio was found in those with primary polycythaemia compared with normal subjects and patients with secondary polycythaemia. If other causes of an increased helper:suppressor ratio are excluded this variable may be useful in confirming the myeloproliferative nature of patients with erythrocytosis.

Adult↗
PubMedDate not supplied

Hematological consequences of profound hypothermic circulatory arrest and aortic dissection.

The lower temperatures utilized during profound hypothermic circulatory arrest (PHCA) surgery may exacerbate the hypothermia associated platelet and clotting factor dysfunction observed in conventional cardiopulmonary bypass (CPB) procedures. Hypothermia has been shown to impair the activity of the enzymes involved in the platelet activation pathways and to reduce the enzymatic activity of clotting factors upon coagulation activation. The resulting retardation of the generation of fibrin/platelet clot compounded by the presence of heparin may contribute significantly to a bleeding tendency. Excessive fibrinolytic activity may disrupt surgical wound thrombi and exacerbate haemorrhage. There is good evidence that the fibrinolytic activity, mediated predominantly by tissue plasminogen activator (tPA), is a secondary response to thrombin generated by coagulation activation, which is ongoing during CPB despite full heparinization. The effects of hypothermia on the fibrinolytic response remain to be clarified and the extent to which the lower temperatures and blood stasis associated with PHCA moderate this response is unknown. Despite impairment of coagulation activation by hypothermia there appears to be a shift in the hemostatic balance towards thrombosis presumably as a consequence of endothelial cell injury by both hypothermia and stasis induced ischemia. There is evidence that widespread microvascular thrombus deposition may occur as a consequence of stasis in patients undergoing PHCA and that this might result in vascular occlusion and end organ damage. Although it is not uncommon to find laboratory evidence of disseminated intravascular coagulation (DIC) in patients presenting with aortic aneurysm rupture or dissection, the incidence of clinically overt DIC resulting in bleeding is low. The underlying hemostatic disturbance however may contribute to the surgery-associated bleeding diathesis.

Aortic Dissection↗