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Biomedical subjects

A J Barnes

Publications and source records attributed to A J Barnes.

At least 19 recordsLinked to original sources
PubMed1998

PCR-ELISA for the early diagnosis of invasive pulmonary aspergillus infection in neutropenic patients.

AIM: To evaluate a newly developed aspergillus mitochondrial gene PCR-ELISA assay for the early diagnosis of invasive pulmonary aspergillosis (IPA) in neutropenic patients. METHODS: The aspergillus mitochondrial gene was chosen for the amplification target for use with a solution hybridisation assay with colorimetric end stage detection in microtitre plate format (PCR-ELISA). The study group comprised neutropenic patients undergoing febrile episodes not responding to standard antibacterial antibiotics. Patients underwent computed tomography and bronchoscopy. Bronchoalveolar lavage (BAL) fluids were examined by culture and PCR. RESULTS: The aspergillus mitochondrial gene PCR-ELISA was both sensitive (100%) and specific (100%) for IPA in neutropenic patients. All 12 patients with definite or probable IPA had PCR positive BAL fluids. None of the patients with undiagnosed or confirmed infections of other aetiologies were mitochondrial PCR positive. Speciation based upon amplicon size difference was possible. CONCLUSIONS: Aspergillus mitochondrial DNA PCR-ELISA on BAL fluid is useful in the early diagnosis of IPA in neutropenic patients alone or, potentially, as an indication for thoracic computed tomography.

Adolescent↗
PubMed1997

Evaluation of routine surveillance urine cultures in rehabilitation ward admissions: a prospective study.

OBJECTIVE: To assess the value of routine surveillance urine cultures and the prevalence of bacteriuria in the younger disabled patient subgroup admitted to the younger disabled unit (YDU). Most of these patients do require some form of assisted urinary drainage. DESIGN: A prospective study of 50 consecutive patients admitted to the YDU for short-term rehabilitation were screened by obtaining relevant clinical details and urine specimens at weekly intervals. INTERVENTIONS: Relevant clinical details were retrieved from case notes and minimum of two urine specimens were collected for culture from each patient. MAIN OUTCOME MEASURES: Presence of positive urine culture, sensitivity and clinical symptoms were recorded. RESULTS: Out of 50 patients studied, 27 were on some form of urinary drainage. Urine culture and sensitivity results were positive in 35 patients. Cultures were predominantly mixed growth or coliform organisms. CONCLUSIONS: Majority of patients were admitted with asymptomatic bacteriuria. There was no evidence to suggest that these short-term rehabilitation patients acquired nosocomial uropathogens and routine surveillance urine cultures were not particularly useful in this setting.

Adolescent↗
PubMed1996

Fatal Candida tropicalis fungaemia in a leukaemic patient receiving fluconazole prophylaxis.

A 50-year-old man with newly diagnosed acute myeloid leukaemia developed breakthrough candidaemia while receiving fluconazole as antifungal prophylaxis during remission-inducing chemotherapy. Candida tropicalis was isolated; the strain was resistant to fluconazole on in vitro sensitivity testing, a phenomenon which has not been previously reported in this setting.

Antifungal Agents↗
PubMed1995

A silicon micromachined device for use in blood cell deformability studies.

An application of silicon micromachining to the analysis of blood cell rheology is described. The system, based upon a micromachined flow cell, provides a specific measurement of each cell in a statistically significant population in terms of both flow velocity profile and an index of cell volume while the cells flow through an array of microchannels. The rationale, design, and fabrication of the silicon micromachined flow cell is discussed. Interrelated considerations determining the design of the associated fluidic, mechanical, imaging, and real-time image analysis subsystems are examined. Sample data comparing normal and iron deficiency anaemic blood are presented to illustrate the potential of this technique.

Blood Cells↗
PubMed1986

Glycosylated plasma protein measurement by a semi-automated method.

A semi-automated method for determination of glycosylation of plasma proteins using the thiobarbituric acid method is described. Plasma samples (100 microL) and a plasma pool used as a secondary standard were incubated in 0.3 M oxalic acid at 100 degrees C for exactly 2 h. The hydroxymethyl furfural released and the total protein were measured concurrently on a Technicon AAII Autoanalyzer. Addition of 10 or 20 mmol glucose to plasma samples caused a minimal increase in the measured glycosylated protein. Within-batch and between-batch coefficients of variation were 3.1% and 4.9% respectively. The mean glycosylated protein levels for 52 normals and 48 maturity-onset diabetics were (+/- 1SD) 0.96 +/- 0.13 and 1.75 +/- 0.32 nmol HMF/mg protein/2 h incubation.

Autoanalysis↗
PubMed1985

Severe retinopathy and mild carbohydrate intolerance: possible role of insulin deficiency and elevated circulating growth hormone.

8 patients with severe progressive diabetic retinopathy despite continued mild carbohydrate intolerance on diet therapy alone were studied; each patient had presented initially with visual deterioration and none had experienced hyperglycaemic symptoms. By comparison with 8 carefully matched diet-treated diabetics without retinopathy, the retinopathy patients had increased circulating growth hormone levels and relative insulin deficiency. Several other factors of possible importance in the aetiology of microangiopathy, including circulating intermediary metabolites, platelet aggregation, blood viscosity, and lipids were similar in the two groups. It is possible that hypoinsulinaemia together with growth hormone excess may contribute to the development of eye disease in these patients with otherwise mild diabetes.

Adult↗
PubMed1985

Loss of diabetic control and increased protein glycosylation following minor intercurrent infections.

To investigate the effect of intercurrent infections, 30 insulin-dependent diabetics and 12 normal subjects were followed prospectively during one winter, with short-term periods of control being assessed by the degree of glycosylation of plasma proteins. Eight diabetics and 7 normal subjects developed an intercurrent infection. During stable control, the diabetics had a mean +/- 1 S.D. glycosylation of 0.90 +/- 0.06 nmol HMF/mg protein/2 hour incubation, compared with the normal subjects of 0.63 +/- 0.04 nmol HMF/mg protein/2 hour. Following infection, there was no increase in glycosylated plasma protein in the normal subjects, but the diabetics increased at 3 and 6 days to 1.07 +/- 0.17 and 1.12 +/- 0.17 nmol HMF/mg protein/2 hour respectively (p less than 0.05 and p less than 0.01). This was similar to levels (1.09 +/- 0.20 nmol HMF/mg protein/2 hour) found in 12 diabetic subjects admitted to hospital because of marked loss of control with ketonuria. The marked protein glycosylation effect of temporary loss of glucose control following 'minor' intercurrent infections suggests that more attention should be paid to diabetic control during brief illnesses.

Adult↗
PubMed1984

Abnormal endothelial release of fibrinolytic activity and fibronectin in diabetic microangiopathy.

Endothelial cell function in Type 1 (insulin-dependent) diabetic patients, both with and without retinopathy, was assessed by measuring the plasma fibrinolytic activity and fibronectin after 10 min venous stasis induced by a sphygmomanometer cuff. After venous stasis, diabetic subjects with proliferative retinopathy had fibrinolytic responses (median 0.13 increasing to 0.26 U/ml) in the low normal range, which were significantly less (p less than 0.005) than control subjects (0.17-0.68 U/ml) and diabetic patients with minimal retinopathy (0.16-0.68 U/ml; p less than 0.01). Plasma fibronectin levels were similar in the different groups, but after venous stasis, rose significantly in the diabetic patients, both in those with proliferative retinopathy (mean 317-399 micrograms/ml; p less than 0.002) and without retinopathy (312-371 micrograms/ml; p less than 0.05) but not in normal subjects (304-333 micrograms/ml). These changes in fibrinolytic activity and fibronectin were independent of blood glucose, glycosylated haemoglobin, or indices of sensory or autonomic nerve function. These disturbances of endothelial function, together with known abnormalities of haemostatic variables and microvascular reflexes, might convert a usually temporary obstruction of capillary blood flow into a pathological capillary closure, and might contribute to the inexorable progression of advanced diabetic microangiopathy in spite of good diabetic control.

Diabetes Mellitus, Type 1↗
PubMed1981

Effect of a long-acting octapeptide analogue of somatostatin on growth hormone and pancreatic and gastrointestinal hormones in man.

1. The biochemical specificity and duration of action of a single 5 mg subcutaneous dose of des-AA1,2,4,5,12,13-D-Trp8-somatostatin were evaluated in eight patients with symptomatic pancreatic endocrine tumours. 2. There was a reduction by more than 50% for at least 10 h in plasma concentrations of growth hormone, glucagon, gastrin and motilin and for 4--5 h in plasma insulin, pancreatic polypeptide, gastric inhibitory polypeptide and enteroglucagon. 3. This study shows that this octapeptide analogue of somatostatin, like somatostatin itself, lacks specificity in the hormones it suppresses. However, its prolonged duration of action against several hormones when given subcutaneously suggests that it may be of therapeutic use in a number of disease states where excessive plasma concentrations of one or more of these hormones occur.

Gastrointestinal Hormones↗
PubMed1981

The effect of somatostatin analogs on secretion of growth, pancreatic, and gastrointestinal hormones in man.

The potency and specificity of somatostatin (SS) and four of its analogs were compared in seven patients with pancreatic endocrine tumors. The analogs tested were [D-Trp8]-SS, [D-Trp8, D-Cys14]-SS, Des-Asn5-[D-Trp8, D-Ser13]-SS, and Des (AA)1,2,4,5,12,13, [D-Trp8]-SS, and they did not show selective effects on the suppression of basal concentrations of GH, insulin, glucagon, pancreatic polypeptide, gastrin, gastric inhibitory peptide, motilin, enteroglucagon, or neurotensin. The observation that the potency of these analogs is similar to that of the parent molecule throws considerable light on the structure/activity relationship of the somatostatin molecule. Des-AA1,2,4,5,12,13, [D-Trp8]-Ss has been reported to have a prolonged action when administered sc. When administered iv, however, this octapeptide analog ws not long acting, suggesting that the prolonged action seen in the previous study was a result of delayed uptake from the injection site. An increment in plasma SS concentrations of 19 +/- 3 pmol/liter suppressed basal concentrations of GH, insulin, glucagon, and several gastrointestinal hormones by more than 50%, suggesting that even small changes in plasma SS levels may be physiologically important.

Adult↗
PubMed1981

Filterability and vascular disease--I. Red cell filterability in diabetes mellitus: its relation to other methods of measuring deformability and to blood viscosity.

Erythrocyte deformability, blood viscosity and other rheological variables were measured in 30 diabetics and 28 normal control subjects. Measurements of red cell rheology were made simultaneously by filtration of whole blood, centrifugation and viscometry of packed red cells. The diabetics showed a significant reduction of erythrocyte deformability measured by filtration, an increase in flexibility measured by centrifugation and values similar to normals for viscometry of packed red cells. Plasma viscosity but not whole blood viscosity (shear rates 23 and 230 s-1) was increased in the diabetics. Erythrocyte flexibility as measured by centrifugation was significantly related to blood viscosity and plasma fibrinogen and glucose in the diabetics, however, neither filtration nor viscometry of packed red cells correlated with other rheological variables. It seems likely that multiple rheological abnormalities are present in diabetes mellitus. Conclusions about erythrocyte rheology in particular will depend critically on the methodology used.

Adult↗