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Biomedical subjects

J Stuart

Publications and source records attributed to J Stuart.

At least 73 records · Page 4Linked to original sources

Low-dose factor VIII in adults with haemophilic arthropathy.

27 adults with haemophilic arthropathy infused freeze-dried factor-VIII concentrate at a mean initial dose of 7.3 and 5.5 units/kg, respectively, during two successive 6-month periods of home therapy. A single infusion at either dosage level successfully terminated over 80% of bleeds. A 32% reduction in use of concentrate was achieved at the lower dose, with a cost saving equivalent to pounds 30 000 per annum and with no apparent short-term clinical disadvantage. Thus low-dose therapy can be successfully applied to severely affected adult patients with established haemophilic arthropathy.

Adolescent

Coagulation activation and hyperviscosity in infection.

A serial study of coagulation activation and whole-blood viscosity was performed on 37 patients with local or systemic bacterial infection, malaria, or a viral infection. Thrombocytopenia, without consumption of coagulation factors, was the main feature of benign tertian malaria and viral infection, whereas in septicaemia and malignant tertian malaria it was associated with activation of coagulation and fibrinolysis. Patients with evidence of intravascular coagulation showed the highest levels of factor VIII related antigen which did not correlate with fibrinogen and probably reflected vascular endothelial cell damage rather than an acute-phase protein reaction. Hyperviscosity, which has been implicated in the pathogenesis of endotoxic shock and cerebral malaria, occurred in parallel with the acute-phase rise in plasma fibrinogen. There was, however, no evidence to implicate hyperviscosity as a major causative factor in the pathogenesis of septic shock or severe infective illness.

Adolescent

Serial changes in coagulation and viscosity during sickle-cell crisis.

Coagulation activity and whole-blood viscosity were measured in the steady state, and serially during painful crisis, in eight patients with sickle-cell anaemia. Platelet and coagulation activation occurred in the steady state and became more pronounced early in crisis. Whole-blood viscosity increased during crisis in parallel with plasma fibrinogen. Similar changes were found in a parallel study of 20 patients with localized bacterial or viral infection who did not have sickle-cell anaemia. Reports of platelet activation, hypercoagulability, and hyperviscosity during painful crisis therefore reflect secondary changes arising from vascular stasis, precipitating infection, and an acute-phase protein reaction. Although secondary, these changes may contribute to vascular occlusion by an additive effect in vessels already partially occluded by sickled cells.

Adolescent

Neutrophil cytochemistry in bacterial infection.

A new cytochemical technique, sensitive to altered lysosomal membrane permeability of blood neutrophils, has been evaluated as a screening test for bacterial infection. This technique, for the lysosomal enzymes acid phosphatase and chloroacetate esterase, was compared with the neutrophil alkaline phosphatase and nitroblue tetrazolium tests. The mean score for each method was significantly higher in infected patients than in normal controls. There was, however, considerable overlap of individual scores between infected patients and ill, but uninfected, patients. This overlap limits the diagnostic value of existing cytochemical screening methods.

Acid Phosphatase

C-reactive protein for rapid diagnosis of infection in leukaemia.

C-reactive protein, measured in serum from 38 patients with leukaemia, was elevated to at least 100 mg/l at the beginning of 32 of 34 episodes of infection, and subsequently rose above 100 mg/l in all 34. Uninfected patients, whether in leukaemic remission or relapse and whether pyrexial or not, always had levels below 100 mg/l, with four exceptions out of 290 measurements. Estimation of two other acute-phase proteins, alpha 1-antitrypsin and orosomucoid, was not of additional diagnostic value. Serial measurement of C-reactive protein may be important for the early detection of infection in the leukaemic patient with neutropenia.

C-Reactive Protein

Fibrinolytic activity of tissue surfaces during surgery.

A non-invasive method has been developed for the study of tissue surface fibrinolytic activity during surgery in man. Surface exudate was collected using a filter-paper disc which was then applied directly to a fibrin plate or used to prepare a euglobulin fraction. The method detected the intraoperative increase in fibrinolytic activity. At 45 minutes from the start of surgery the increase in lytic activity for tissues was four to eight times greater than that of venous blood taken simultaneously. The technique may be used to compare regional differences in tissue fibrinolysis, to determine the effect of excess local fibrinolysis on postoperative bleeding, and to study the relation between low fibrinolytic activity and postoperative adhesion formation.

Exudates and Transudates

Medical student concentration during lectures.

A simple procedure, based on a questionnaire, was used for the assessment of student concentration during lectures. Analysis of 1353 questionnaires from 12 lectures showed that student concentration rose sharply to reach a maximum in 10-15 min, and fell steadily thereafter. The data suggest that the optimum length of a lecture may be 30 instead of 60 min. This method by which student feedback is obtained may also be used to improve lecturing performance.

Analysis of Variance

Haemophilia A home therapy in the United Kingdom 1975-6.

Data on home treatment for patients with haemophilia A (factor VIII deficient haemophilia) were compiled for 1975 and 1976 from questionnaires answered by directors of haemophilia centres throughout the United Kingdom. There were 48 haemophilia centres in 1975 and 71 in 1976. The number of patients on or in training for home treatment increased from 267 to 488 in the two years, and a further 241 haemophiliacs were considered suitable for home therapy by the end of 1976. Apart from a small (but increasing) number of haemophiliacs on prophylactic treatment, most patients were on low-dose (250-500 units) on-demand regimens, using a mean of 20 000 factor VIII units per patient per year in 1976. An estimated 55% of the blood product used for home therapy in the UK in 1976 was imported from commercial sources. Despite the fact that the numbers of patients on home treatment have increased, so that about 60% of the potential population were receiving or being considered for home treatment in 1976, inadequacies in the service still remain. In some centres follow-up is clearly inadequate; about 15% of patients still rely on cryoprecipitate; and too little money has been invested in making the NHS self-sufficient in factor VIII production.

Antibodies

The development of serum immunoglobulins G, A and M in Australian Aboriginal infants.

Serum levels of immunoglobulins G, A and M (IgG, IgA and IgM) were studied in a population of Aboriginal infants from birth to 2 1/2 years of age. Serum levels of all three immunoglobulins were found to be consistently higher than in studies of white children. This is attributed to increased exposure of Aboriginal infants to infectious agents from early in life.

Australia

Coagulation and fibrinolytic activity of cerebrospinal fluid.

Fibrin/fibrinogen degradation products (fragments D and E) were detected in cerebrospinal fluid in 23.4% of 252 patients admitted to a neurological/neurosurgical unit. Other coagulation proteins of low molecular weight (plasminogen and factor IX) were also present but larger proteins (fibrinogen and factor V) were not. These findings are consistent with protein leakage across a blood-CSF barrier damaged by inflammatory, vascular, or neoplastic disease. Fibrin/fibrinogen degradation products in cerebrospinal fluid after subarachnoid haemorrhage may not, therefore, be a reliable index of increased fibrinolytic activity in the subarachnoid space and may be misleading when selecting patients for fibrinolytic blockade.

Acute Disease

Lysosomal enzyme cytochemistry of blood neutrophils.

Patients with bacterial infection may show altered membrane permeability of the primary azurophilic lysosomes of blood neutrophils. A new enzyme cytochemical technique, sensitive to increased membrane permeability caused by contact of neutrophils with acetone, saponin, low pH, Streptolysin O, bacteria, and nylon wool, has been developed. The method is of potential value as a screening test for bacterial infection and for detecting neutrophil damage during filtration leucopheresis.

Acetates

A new host gene (groPC) necessary for lambda DNA replication.

The isolation of a bacterial mutation in a gene, designated groPC, which affects the growth of phages lambda and P2 is described. Lambda replication is severely limited in the strain, and some lambda pi mutations, which map in (or near) the P gene, allow growth. The gro mutation, groPC259, is recessive to wild type and maps between threonine (thr) and diaminopimelate (dapB) on the E. coli chromosome. The possibility that the groPC gene is concerned with host DNA replication is discussed.

Chromosome Mapping

Hyperfibrinogenaemia and hyperviscosity in sickle-cell crisis.

Plasma fibrinogen concentration and whole-blood viscosity, the latter measured at two shear rates (23 and 230 sec-1), were estimated during eight episodes of sickle-cell crisis and compared with values in 26 sickle-cell anaemia patients who were not in crisis. Painful crisis was associated with a significant increase in both plasma fibrinogen and whole-blood viscosity. Increased fibrinogen-erythrocyte interaction in vivo may be a significant contributory factor to raising blood viscosity and precipitating vaso-occlusive crisis in sickle-cell disease.

Adolescent

Fibrin-fibrinogen degradation products in cerebrospinal fluid.

An increase in low molecular weight fibrin-fibrinogen degradation products (FDP) was demonstrated in cerebrospinal fluid (CSF) from 17 of 18 patients with bacterial or viral meningitis compared with 29 patients without meningitis. The CSF also showed an increase in coagulation proteins of molecular weight less than 90000 (factors VII, IX, and plasminogen) but did not contain fibrinogen (MW 340000) or plasminogen activator. It is concluded that low molecular weight FDP in the CSF in infective meningitis result from leakage through a damaged blood-CSF barrier rather than from local digestion of fibrin deposited on the meninges.

Child