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Biomedical subjects

J Stuart

Publications and source records attributed to J Stuart.

At least 145 records · Page 8Linked to original sources
PubMed1975

Enzyme cytochemistry of blood and marrow cells.

Diseases of the blood and bone marrow are commonly associated with abnormalities of oxido-reductase and lysosomal enzymes within individual erythrocytes and leucocytes. There are considerable technical difficulties, however, in adapting enzyme histochemical techniques to the study of haemopoietic tissue since individual cells are readily disrupted during processing, show variable enzyme activity according to the stage of maturation, and possess a lipoprotein cytoplasmic membrane which hinders reagent penetration. Cytochemical techniques for the study of oxido-reductase systems are of importance in the study of the neutrophil in infected patients, the erythrocyte in glucose-6-phosphate dehydrogenase deficiency, and the primitive blast cell in acute leukaemia. Lysosomal enzymes are of importance in the study of the neutrophil in infected patients and in the differential diagnosis of acute leukaemia. Some examples of recent studies of these enzyme systems are given to illustrate technical procedures involving cytocentrifugation of cells on to glass slides, adjustment of the osmolality of the reaction mixture, and the study of smeared cells as opposed to cells incubated in suspension.

Acid Phosphatase↗
PubMed1975

Serum gonadotrophins in young children.

LH and FSH were assayed in serum samples from children ranging from newborn to 13 years. In boys, LH was found in most samples up to 4 months of age, in many up to 10 months, but in only 38 percent between 1 and 8 years. In girls, it was found in only 29 percent of the samples under 1 year and the frequency and concentration changed little thereafter until 8-10 years. FSH was detected in all samples from boys up to 4 months and in most of those from girls up to 2 years. After these ages the frequency declined in each sex and there was little further change until 8-10 years. Between 1 and 8 years the proportion of samples containing either FSH or LH was similar for the two sexes, but whereas in boys high LH tended to be associated with high FSH, and vice versa, there was no such correlation in girls. The results are discussed in relation to gonadal development and steroid synthesis.

Adolescent↗
PubMed1975

Excess intravascular coagulation complicating low cardiac output.

In 42 children with congenital heart disease coagulation factor levels were studied serially during the first 20 hours following cardiopulmonary bypass surgery. The acyanotic patients, and also cyanotic patients who survived the operation, showed a progressive improvement in their coagulation profile from initial low postoperative levels. In 12 cyanotic patients who died within 72 hours, however, the coagulation factor levels either remained low, or fell further, until death. Fresh frozen plasma was administered to eight of these patients without apparent benefit. The abnormal coagulation profile correlated significantly with low skin temperature and increased blood loss and was considered to represent excess intravascular coagulation secondary to low cardiac output and poor tissue perfusion.

Blood Coagulation Disorders↗
PubMed1975

Anaemic crisis in sickle cell disease.

Sixteen episodes of acute anaemia necessitating urgent blood transfusion have been investigated in 13 children with sickle cell anaemia. In five out of seven episodes there was evidence of increased haemolysis while in 10 out of 16 episodes a profound fall in reticulocyte count indicated marrow erythroid cell failure. Cold agglutinins active at room temperature were detected in 13 episodes, and anti-I specificity was demonstrated in 11. Warmed blood of homologous ABO and Rhesus groups was administered without complication despite difficulty with cross-matching. The exacerbation of anaemia was not due to folate lack, glucose-6-phosphate dehydrogenase deficiency or splenic sequestration, and an infectious agent appeared responsible. The degree of anaemia in homozygous sickle cell disease is usually constant during asymptomatic periods. An episode of sudden profound anaemia (anaemic crisis) may, however, result from marrow hypoplasia, an exacerbation of haemolysis, splenic sequestration, or folate deficiency.

Acute Disease↗
PubMed1975

The cytocentrifuge NBT test.

The NBT test is a non-specific test of neutrophil membrane stimulation which has application to the study of neutrophil function, particularly in the septicaemic patient. An improved cytochemical test which eliminates potential sources of laboratory error has been developed. Venous or capillary blood samples may be studied and the technique can be applied to the neutropenic patient since available neutrophils are concentrated by cytocentrifugation. Clinical evaluation in 443 patients is described.

Adolescent↗
PubMed1975

The effect of vitreous humor on fluid transport by rabbit corneal endothelium.

The effects of vitreous humor and some of its components on the function of rabbit corneal endothelium were investigated and compared to those of artificial and natural aqueous humor. The rate of fluid pumping across the endothelium was measured while that layer was in contact with: (1) complete medium, an artificial aqueous solution; (2) pooled rabbit aqueous humor; (3) filtered and (4) unfiltered pooled rabbit vitreous humor; and (5) solid residue from vitreous humor. The relative magnitudes of the rates were: complete medium greater than aqueous larger than or equal to filtered vitreous greater than vitreous larger than or equal to solid residue. A definite adverse effect of unfiltered vitreous and of its solid residue on endothelial pumping was observed. It is suggested that the solid (collagenous) elements in vitreous humor may be responsible for these effects and perhaps for those generically referred to as the "vitreous touch syndrome" in clinical studies.

Animals↗
PubMed1975

Rapid, specific assay for plasma cortisol by competitive protein binding.

We describe a modified competitive protein-binding method for assay of plasma cortisol. Plasma samples are deproteinized by dilution with an ethanol/phosphate buffer, followed by heating at 100 degrees C for 2 min. Horse serum is used as the source of transcortin. Free radioactivity is separated from the protein-bound component by partition into liquid scintillation counting within 60 min. The assay has better specificity and precision than a competitive protein-binding assay in which ethanol extraction and Florisil adsorbent are used, and results correlate well with those of a specific radioimmunoassay method.

Binding, Competitive↗
PubMed1974

Thrombolytic therapy in haemolytic--uraemic syndrome.

The treatment of five children with the haemolytic-uraemic syndrome using streptokinase is described to illustrate the difficulties and limitations of thrombolytic therapy in this disease. This experience is germane to the design of multicentre clinical trials.A multivariate analysis relating clinical outcome to the data obtained at the time of admission was also carried out for 31 children with the disease treated in four centres. The results suggest that this technique may help to identify those patients likely to have a fatal outcome. An expanded form of this type of analysis should be incorporated in future clinical trials.

Blood Cell Count↗
PubMed1974

Capillary blood collection in haematology.

A capillary blood collection technique which facilitates the estimation of routine haematological parameters, including platelet count and sedimentation rate, is described. The technique requires 0.5 ml of blood, allows closer reproducibility than pipette collection methods, is suitable for monitoring blood counts in patients receiving cytotoxic agents, and can be integrated with semi-and fully-automated production lines.

Adult↗
PubMed1974

Training of pathologists by a system of modules.

The training requirements of the individual pathology subjects within laboratory medicine are changing rapidly and there is a trend to earlier specialization. A new training scheme based on a system of 10 modules, each of six months' duration, is suggested. Six of the modules comprise obligatory specialist training while the remaining four provide an element of choice both in subject matter and timing. This allows the advantages of multidisciplinary training to be retained, despite earlier specialization, since the subjects studied need not necessarily be restricted to the traditional pathology disciplines. The system allows 20% of training time to be devoted to full-time research and has been designed to be attractive to trainees in general medicine. Modular training provides an inherently flexible system which can readily be adapted to future developments in pathology and medicine.

Education, Medical, Graduate↗
PubMed1974

Coagulation fibrinolysis in sickle-cell disease.

A study of fibrinolytic activity in sickle-cell patients during asymptomatic periods has shown a normal fibrinolytic response to exercise and local heat to the arm. During vasoocclusive crises there was no significant decrease in fibrinolytic activity. These results contrast with earlier reports of decreased fibrinolysis during crisis and a suggestion that fibrinolytic activators might be of value in preventing vasoocclusive episodes. Patients in painful crisis showed a significant rise in fibrinogen concentration and fall in platelet count. The former may contribute to localized vascular sludging by increasing whole-blood viscosity, while the latter probably results from local trapping of platelets in areas of sickling or from subsequent splenic sequestration of damaged platelets. There was no evidence of disseminated, as opposed to localized, intravascular coagulation during crisis.

Adolescent↗
PubMed1973

Screening for abnormal haemoglobins: a pilot study.

A pilot study has been made of the implication of screening for abnormal haemoglobins in immigrant schoolchildren. An abnormality was detected by capillary blood haemoglobin electrophoresis in 8.4% of 6,835 children and a haemoglobinopathy outpatient clinic had to be established to deal with the heavy work load which resulted. The clinic was also used to determine the value of investigating the remaining members of the family once an abnormality had been detected in one child.Healthy siblings with normal haemoglobin electrophoretic patterns and normal iron and folate levels were studied to determine a normal range for haemoglobin in relation to age for adequately nourished immigrant children. The lower limit of the normal range was close to the mean value minus 1(1/2) S.D.; by using this definition 10.3% of 280 children were subsequently found to be anaemic.Population screening of this type is desirable, but further pilot studies of patient education, genetic counselling, organization of specimen collection, data processing, and follow-up health care facilities are required before screening is extended more widely in the United Kingdom.

Adolescent↗