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Biomedical subjects

D A Robertson

Publications and source records attributed to D A Robertson.

At least 91 records · Page 5Linked to original sources
PubMed1981

Blood viscosity after splenectomy.

Blood viscosity and its contributory factors--namely, plasma viscosity, fibrinogen concentration, packed cell volume, red-cell deformability, and platelet count--were measured in 20 asymptomatic patients after splenectomy and compared with those in controls. Whole-blood viscosity was significantly increased after splenectomy and was associated with increased platelet count and, more importantly, decreased red-cell deformability. Blood viscosity was measured in six patients before and after splenectomy and in each an increase in viscosity occurred that did not occur in patients who underwent laparotomy without splenectomy. these findings suggest that the inclusions and protein complexes within the red cell that are normally removed by the spleen decrease red-cell deformability and lead to an increase in blood viscosity. This may account for the observed increase in deaths from ischaemic heart disease many years after splenectomy.

Adolescent↗
PubMed1981

HLA-B8 and cell-mediated immunity to gluten.

The leucocyte migration inhibition (LMI) test was used as an indicator of cell mediated immunity to gluten fraction III in 30 healthy controls and 58 patients with adult coeliac disease and the results related to HLA status and duration of treatment with a gluten-free diet. HLA-B8 controls showed significantly lower leucocyte migration indices, indicating greater immune response, than non-HLA B8 controls. Untreated coeliacs showed no difference from HLA-B8 controls. There was no difference between results from HLA-B8 and non-HLA-B8 coeliacs. Leucocyte migration was even lower in coeliacs early in treatment but rose after treatment for over one year. These results may reflect an immune response gene for gluten in linkage disequilibrium with HLA-B8. The increased immune response to gluten as measured in this test cannot be the sole factor in aetiology of coeliac disease. Furthermore, it is necessary to re-evaluate earlier results of cell-mediated immunity in coeliac disease with reference to HLA status of the controls.

Celiac Disease↗
PubMed1979

Intra-individual variation in commonly analyzed serum constituents.

Concentrations of 27 commonly estimated serum constituents were measured in blood sampled from 20 apparently healthy volunteers at 0830, 1230, and 1630 hours on each of four days, at weekly intervals. Time-dependent statistically significant (p less than or equal to 0.01) variation was observed in 12 of the constituents. The 15 constituents that showed no statistically significant diurnal variation included the immunoglobulins, other specific proteins, enzymes, cholesterol, calcium, copper, and magnesium. On the different days of the study consistent temporal patterns were observed in urea, creatinine, phosphate, zinc, bilirubin, triglyceride, total protein, and albumin. The magnitude of variation was particularly great in potassium, iron, zinc, and bilirubin. In general, day-to-day changes in concentration exceeded within-day changes, except for potassium, phosphate, and zinc, for which greater changes could be observed within-day than from one day to another at the same time.

Alanine Transaminase↗
PubMed1977

Some biochemical similarities and differences between two jack mackerel species, Trachurus declivis and T. novaezelandiae.

1. Six proteins, haemoglobin (two loci), serum esterase (two loci) and lactate dehydrogenuase (two loci) from two species of jack mackerel, Trachurus declivis and T. novaeselandiae, were compared electrophoretically. All six loci were found to be monomorphic. 2. LDH from red and white skeletal muscle tissue were electrophoretically different, but the red form and the white form were found to be identical in both species. 3. Both species share an electrophoretically identical serum esterase, but each species also has an electrophoretically distinct serum esterase. 4. Both species share an electrophoretically identical haemoglobin, but each species also has an electrophoretically distinct haemoglobin. 5. The otolith iron contents of the two species were compared and found to be identical.

Animals↗
PubMed1977

Some problems in the correction for intrinsic light-scattering of samples in specific protein analysis by automated immunoprecipitation.

Heparinised plasma samples have falsely high blank values in the automated immunoprecipitation system when blanks are measured by omitting antiserum from the assay. This is probably due to an interaction of heparin and serum proteins, together with either fibrinogen or polyethylene glycol. A more accurate estimate of the blank of heparinised plasma samples is obtained by measuring it with a solution of nonimmune serum substituted for the antiserum.

Blood↗
PubMed1977

Clinical information from medical images. A comparison of two types of ultrasonic image in the detection of focal intrahepatic lesions.

If the uncertainty in the diagnosis is measured before and after viewing a diagnostic image, the change in uncertainty is a measure of the information contributed by that image. The formal basis of information theory has been used to calculate the change in uncertainty. These analytical methods have been applied to assess two types of ultrasonic grey-scale image in the demonstration of possible focal intrahepatic lesions.

Humans↗
PubMed1976

The accuracy of caridac function indices derived from ultrasonic time-position scans.

A study has been made of Time-Position ultrasonic scanning as a means of obtaining measurements related to cardiac performance. The errors involved in determining these measurements have been estimated. It has been shown that the greatest accuracy can be achieved for quantities which depend on action rather than shape, such as ejection fractions and rates of myocardial fibre shortening. Attention is drawn to the fact that the ultrasonic method, unlike angiography, in no way alters the quantities being measured.

Cardiac Output↗
PubMed1975

Ultrasonic measurement of prosthetic heart valve action.

An in-vitro study has been made of the echo patterns obtained during ultrasonic Time-Motion (T-M) scanning of commonly used prosthetic heart valves. Studies have been undertaken of Starr-Edwards, Beal, and Björk-Shilley valves. From the recorded traces information has been obtained regarding the orientations of the ultrasound beam to the central axes of the valves for which accurate measurements can be made. The orientations have been determined for which the opening and closing times of the valves can be measured to within 20 ms. Characteristics of the T-M trances have been noted which allow the angle between the direction of an ultrasound beam and a central valve axis to be reduced to less than 20 degrees. This makes the error due to angular misalignment of the beam less than --6% when the range of movement of a ball, disc, or flap is being measured. Finally a number of artefacts are considered which can arise when prosthetic valves are examined with ultrasound.

Heart Valve Prosthesis↗
PubMedDate not supplied

The EASD in Dublin.

Explore the source record for details and available documents.

Diabetes Mellitus↗
PubMedDate not supplied

Is serum anhydroglucitol an alternative to the oral glucose tolerance test for diabetes screening? The Mauritius Noncommunicable Diseases Study Group.

The oral glucose tolerance test is inconvenient for diabetes screening. In clinical studies a reduced serum anhydroglucitol level has proved to be a sensitive and specific test for diabetes. A new minicolumn enzymatic method which is simple and robust makes use in population screening feasible. The aim of our study was to assess the usefulness of a single measurement of anhydroglucitol to screen for diabetes and impaired glucose tolerance. Assays were performed on samples taken from 227 Mauritian Chinese subjects at the time of glucose tolerance testing. Subjects had normal glucose tolerance (n = 82), impaired glucose tolerance (n = 76), newly diagnosed diabetes (n = 38), and known diabetes (n = 31). Anhydroglucitol concentrations (mean +/- SD) were similar for normal and impaired glucose tolerance subjects (23.7 +/- 8.2 vs 23.4 +/- 8.6 mg l-1). Although the differences between normal and newly diagnosed diabetes (15.0 +/- 11.0 mg l-1) and known diabetic subjects (11.8 +/- 10.6 mg l-1) were significant (p < 0.001), diagnostic sensitivity and specificity were poor. We conclude that measurement of serum anhydroglucitol is not suitable for screening for the diagnoses of impaired glucose tolerance and diabetes.

Adult↗
PubMedDate not supplied

Problems and pitfalls of sulphonylurea therapy in older patients.

The prevalence of non-insulin-dependent diabetes mellitus (type II) increases with age, so that approximately half of all known patients in English-speaking countries are over 65 years of age. There is no reason to believe that the criteria for blood glucose control should be any less stringent for elderly patients unless they have a limited life expectancy. Sulphonylurea drugs remain an effective means of achieving blood glucose control after failure of dietary therapy alone in older patients. However, changes in normal metabolism of drugs with age and the development of other pathologies in elderly patients make it important that these drugs are prescribed with care. Severe symptomatic hypoglycaemia is the most serious adverse effect of sulphonylurea drugs and this becomes progressively more likely with increasing age, depending primarily on the substantial reduction of renal function with normal aging. Other adverse effects are much less commonly of clinical importance. To minimise the risk of hypoglycaemia, it is important that patients receive closely supervised dietary management with education about their disease for at least 3 months before sulphonylurea drugs are prescribed. In elderly patients a short-acting agent with no active metabolites should be used. As patients become older, those receiving long-acting agents can be changed to short-acting agents before problems arise. If blood glucose control appears satisfactory on treatment, then symptoms of hypoglycaemia should be sought. If control is poor, then the criteria for introduction of insulin, with appropriate education, do not differ from those in younger patients.

Aged↗