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Biomedical subjects

K M Shaw

Publications and source records attributed to K M Shaw.

At least 37 records · Page 2Linked to original sources
PubMed1996

Apolipoprotein B independently predicts progression of very-low-level albuminuria in insulin-dependent diabetes mellitus.

The purpose of the study was to examine the contribution of alterations in lipoprotein metabolism to the progression of very-low-level albuminuria in insulin-dependent diabetes mellitus (IDDM). We measured serum concentrations of lipids, lipoproteins, and apolipoproteins in 53 normoalbuminuric diabetic patients without overt hypertension, whom we restudied after 10 years. Albuminuria was measured as the urinary albumin to creatinine ratio (UA/UC) in repeated early-morning samples. Over 10 years, UA/UC increased significantly (P < .001), and five patients (9.4%) progressed to microalbuminuria. The increase in albuminuria was significantly and positively related to the baseline serum concentrations of total cholesterol (P < .05), low-density lipoprotein (LDL) cholesterol (P = .05), non-high-density lipoprotein (HDL) cholesterol (P < .05), and apolipoprotein (apo) B (P < .001), but no significant associations were found with triglycerides, HDL cholesterol, apo A-1, or lipoprotein(a) [Lp(a)]. The relative risk of developing microalbuminuria for a serum apo B concentration more than 1.1 g/L was 3.8 (95% confidence interval [CI], 1.9 to 7.7). In multiple linear regression analysis, serum apo B (P < .05) and glycated hemoglobin ([HbA] P < .05) at baseline were significant independent predictors of the increase in albuminuria, with no significant associations found for sex, smoking, duration of diabetes, mean arterial blood pressure (BP), or family history of cardiovascular disease and hypertension; the regression model predicted 42% of the variation in UA/UC at 10 years. The findings suggest that an abnormality in the metabolism of apo B may be independently associated with progression of very-low-level albuminuria and possibly with the development of early nephropathy in IDDM patients.

Adult↗
PubMed1995

Exercise testing as a long-term predictor of the development of microalbuminuria in normoalbuminuric IDDM patients.

OBJECTIVE: To determine the association between exercise-induced albuminuria and the development of microalbuminuria over 10 years in subjects with insulin-dependent diabetes mellitus (IDDM) who were initially normoalbuminuric. RESEARCH DESIGN AND METHODS: Thirty-two patients with IDDM and a resting urinary albumin/creatinine ratio (UA/UC) < 2.1 mg/mmol (< 15 micrograms/min) were exercised after water loading on a treadmill for 20 min at double their resting heart rate. UA/UC was determined before and after exercise. The exercise test was considered positive if the UA/UC was > 4.3 mg/mmol (> 30 micrograms/min). Results were compared with resting UA/UC after a 10-year follow-up. Persistent microalbuminuria was defined as a UA/UC > 2.1 mg/mmol (> 15 micrograms/min) in each of two early-morning urine collections. RESULTS: Five patients developed persistent microalbuminuria after 10 years, and four patients were predicted by a positive exercise test. Two patients with positive exercise tests did not develop persistent microalbuminuria. The sensitivity of the exercise test for the development of microalbuminuria was 80% (95% confidence interval [CI] 65.8-94.2%) and the specificity was 92.9% (95% CI 83.9-100%). The postexercise UA/UC was positively associated with the UA/UC after 10 years (P = 0.005, R2 = 0.31). This association was independent of HbA1, systolic blood pressure, body mass index, and duration of diabetes, but HbA1 remained an independent predictor (P = 0.02) of UA/UC at follow-up. CONCLUSIONS: Exercise testing may be useful for identifying normoalbuminuric IDDM patients who are susceptible to the later development of microalbuminuria.

Adult↗
PubMed1994

Role of glycaemic control in development of microalbuminuria in patients with insulin dependent diabetes.

OBJECTIVE: To ascertain which factors determine the progression from very low rates of albumin excretion to persistent microalbuminuria in patients with insulin dependent diabetes mellitus. DESIGN: A 10 year prospective study of a cohort of diabetic patients. SETTING: Outpatient department of the Portsmouth District Hospitals. SUBJECTS: 97 patients with insulin dependent diabetes mellitus who were initially free of microalbuminuria and hypertension. MAIN OUTCOME MEASURE: Urinary albumin: creatinine ratio. RESULTS: Eight of the 97 patients had developed microalbuminuria (urinary albumin:creatinine ratio > 3 mg/mmol in three consecutive early morning samples) by the 10 year follow up. The group who developed microalbuminuria had higher baseline log10 plasma glucose concentrations (mean (SD), 1.210 (0.122) v 0.984 (0.196) mmol/l, P < 0.001) and glycated haemoglobin concentrations (1.112% (0.069%) v 0.997% (0.076%), P < 0.001) and a younger age at onset of diabetes (10.0 (5.5) v 15.6 (7.8) years, P < 0.05). There was no difference in baseline duration of diabetes, smoking, sex, insulin dose, body mass index, serum creatinine concentration, or systolic, diastolic, or mean arterial blood pressure between the two groups. Multiple linear regression analysis showed that urinary albumin:creatinine ratio at 10 years was influenced by initial albumin:creatinine ratio (P = 0.006), initial glycated haemoglobin concentration (P = 0.002), and duration of diabetes (P = 0.045). Genotype for angiotensin converting enzyme was not related to the development of microalbuminuria nor, in a larger group of patients, the presence of any degree of diabetic nephropathy. CONCLUSION: In patients with insulin dependent diabetes mellitus the progression of minimal albuminuria and the development of microalbuminuria is determined primarily by poor long term glycaemic control. There is a weaker relation with longer duration of disease and younger age at onset of diabetes, but blood pressure does not seem to be implicated. Gene polymorphism for angiotensin converting enzyme is not linked to the development of microalbuminuria or established diabetic nephropathy.

Adolescent↗
PubMed1993

The quality of photographs produced by the non-mydriatic fundus camera in a screening programme for diabetic retinopathy: a 1 year prospective study.

A prospective study was performed on the quality of photographs produced by the non-mydriatic fundus camera used in a hospital-based screening programme for diabetic retinopathy. In 1 year 981 binocular patients were photographed. A photograph of acceptable quality was obtained from 90.5% of eyes and 84.4% of patients had an acceptable photograph of both eyes. The photograph of the second eye was more often unacceptable than that of the first. This tendency was significant in females (p = 0.0196) and when considering the sexes together (p = 0.0044), but not significant in males (p = 0.1042). Photographs of unacceptable quality were obtained significantly more often in patients aged over 55 years for both right and left eyes (p = 0.001). An overall improvement in photographic quality might be achieved by allowing full recovery of flash-induced pupil constriction before taking the second photograph and by dilating those aged over 55 years.

Adult↗
PubMed1992

The immunogenetics of early nephropathy in insulin-dependent diabetes mellitus: association between the HLA-A2 antigen and albuminuria.

One-hundred and seventy-two normotensive, insulin-dependent diabetic patients without clinical proteinuria (Albustix negative) were typed for the major histocompatibility complex class I (HLA-A, -B) and class II (HLA-DR) antigens. Urinary albumin excretion was measured as the albumin:creatinine ratio (UA/UC, mg/mmol) in an early morning sample. Patients expressing the HLA-A2 antigen had significantly higher UA/UC values than those not expressing the antigen. The observed ratio of geometric means was 1.77 (95 per cent confidence interval (CI) 1.18-2.67; p < 0.01); the relative risk of microalbuminuria (UA/UC > 3.0 mg/mmol) associated with expression of HLA-A2 was 2.52 (95 per cent CI 1.11-5.73; p < 0.05). There was no significant association between UA/UC and HLA-B8, -B15, -DR3, -DR4 or other antigens. Patients were re-studied after a mean period of 5.3 years: multiple linear regression analysis showed that the UA/UC at this time was positively related to the initial glycosylated haemoglobin level (p < 0.01) and expression of the HLA-A2 antigen (p < 0.05), but not to blood pressure or creatinine clearance. Fifteen patients developed macroalbuminuria at follow-up (UA/UC > 45.5 mg/mmol). Compared with a group matched for age, sex, duration of diabetes, and glycosylated haemoglobin who did not develop macroalbuminuria, macroalbuminuric patients had a higher frequency of HLA-A2 (p < 0.01). The odds ratio of progressing to macroalbuminuria associated with HLA-A2 had a 95 per cent CI of 1.71 to infinity. We conclude that an immunogenetic factor may play a role in the development of early diabetic nephropathy and that the risk associated with expression of the HLA-A2 antigen is independent of metabolic control and blood pressure.

Adolescent↗
PubMed1991

Bleeding intracranial aneurysm? Pituitary apoplexy!

Pituitary apoplexy describes the clinical syndrome characterised by headache, visual impairment and ophthalmoplegia caused by sudden enlargement of a pituitary adenoma. This is usually due to extensive tumour infarction or haemorrhage. Pituitary apoplexy is rare, mimics spontaneous intracranial bleeding, and thus may be easily mistaken for acute subarachnoid haemorrhage. Urgent surgical intervention and hormone replacement therapy are required.

Brain↗
PubMed1991

The determinants of early nephropathy in insulin-dependent diabetes mellitus: a prospective study based on the urinary excretion of albumin.

A four-year prospective study of the factors predicting albuminuria was carried out in 172 normotensive, insulin-dependent diabetic patients without overt nephropathy. Urinary albumin excretion was estimated as the urinary albumin:creatinine ratio (UA/UC) in an early morning sample. Multivariate analysis showed that UA/UC on the return visit was positively associated with the UA/UC (p less than 0.001) and glycosylated haemoglobin (HbA1; p less than 0.001) at initial examination; weaker associations were found with a history of hospital admission (p less than 0.05) and smoking (p less than 0.05), and with treatment of blood pressure (p less than 0.05). Neither initial blood pressure, heart rate, nor creatinine clearance were significant predictors of the UA/UC. Two patients died from coronary heart disease, both of whom had raised albumin excretion at initial examination. Eleven (6.8 per cent) of the 160 patients who were studied repeatedly developed macroalbuminuria (UA/UC greater than 45.5 mg/mmol): they had a significantly higher initial UA/UC (p less than 0.005), HbA1 (p less than 0.05) and a greater frequency of retinopathy (p less than 0.05) than patients matched for age, sex and duration of diabetes who did not develop macroalbuminuria. Simultaneous measurements of the UA/UC and HbA1 should be used when screening for microalbuminuria in diabetes mellitus: patients with a high UA/UC (e.g. greater than 3.5 mg/mmol) and HbA1 (e.g. greater than 13 per cent) should be closely monitored even when blood pressure is normal.

Albuminuria↗
PubMed1989

An acceptable exercise test to study microalbuminuria in type 1 diabetes.

A modified test for studying the response of urinary albumin excretion (UAV) to exercise in diabetic patients is described. It is designed to produce a standardized increase in pulse rate (by 90-110%) rather than a standardized workload. Thirty-three normotensive Type 1 diabetic patients with normal pre-exercise UAV (less than 10 micrograms min-1) on the day of the test were compared with 25 non-diabetic subjects matched for age and sex. The patients developed a significantly greater increase in the median UAV (p less than 0.05) and systolic blood pressure (p less than 0.01) during exercise, despite the use of lower workloads (p less than 0.05). During exercise, the albumin excretion in the patients was not related to their heart rate, blood pressure, workload or fall in blood glucose; nor was it related to duration of diabetes, glycosylated haemoglobin or insulin dose. An exercise UAV greater than 15 micrograms min-1 was found in 10 of the 33 patients; it was significantly correlated (p less than 0.01) with the frequency of previous overnight microalbuminuria (greater than 10 micrograms min-1), and was associated with a greater progression of microalbuminuria (p less than 0.05) over a mean period of 24 months. Retinol-binding protein excretion rate was also measured as an indicator of proximal tubular function and did not increase in either group.

Adult↗
PubMed1989

Low-molecular-weight proteinuria in insulin-dependent diabetes mellitus: a study of the urinary excretion of beta 2-microglobulin and retinol-binding protein in alkalinized patients with and without microalbuminuria.

The urinary excretion of two low-molecular-weight proteins (beta 2-microglobulin and retinol-binding protein) was measured in 12 insulin-dependent diabetic patients with persistent microalbuminuria and an equal number with normal albumin excretion; reference ranges for the excretion of beta 2-microglobulin (beta 2M) and retinol-binding protein (RBP) were also obtained in 40 non-diabetic subjects. To ensure the stability of beta 2M in urine a urinary pH greater than or equal to 7 was achieved by giving oral sodium bicarbonate. beta 2M and RBP excretion was significantly higher in the diabetics than in the controls (p less than 0.01), but no higher in microalbuminuric than non-albuminuric diabetics. In the diabetics as a group a significant correlation was found between the excretion of beta 2M and RBP (r = 0.53, p less than 0.01), but more patients had an abnormal excretion of beta 2M than RBP (p less than 0.001). No significant correlation was found between the urinary excretion of either low-molecular-weight protein and duration of diabetes, insulin dose, HbA1, urinary glucose excretion or systemic blood pressure. Measured under appropriate alkaline conditions beta 2M appears to be more sensitive than RBP in detecting an abnormality of the renal proximal tubule which may be an early feature of diabetic renal involvement not characterized by microalbuminuria; microalbuminuria may have glomerular and tubular components.

Adolescent↗
PubMed1989

Psychometric properties of the Dyskinesia Identification System: Condensed User Scale (DISCUS)

Individuals with developmental disability (N = 400) were assessed with the Dyskinesia Identification System: Condensed User Scale (DISCUS), a 15-item tardive dyskinesia rating scale shortened from the 34-item Dyskinesia Identification System-Coldwater (DIS-Co). Interrater reliability assessments were made for 148 individuals, and 2-week stability (test-retest) assessments were made for 128 individuals. Mean DISCUS total score was 4.1 (SD = 3.5); reliability was .92, p less than .001, and stability was .40, p less than .001. Based upon this study and a larger study of 4,649 individuals with developmental disability, we recommend that clinicians carefully evaluate for tardive dyskinesia any individuals with developmental disability who have been prescribed antipsychotics for greater than 3 months and who score 6 or above on the DISCUS.

Adolescent↗
PubMed1988

Side-room tests to screen for microalbuminuria in diabetes mellitus.

Three side-room tests (latex bead immunoagglutination test, LBT; 25% sulphosalicylic acid test, SST; microalbutest, MAT) for the detection of microalbuminuria in diabetics are described and their screening potential and practicability assessed. One hundred insulin-dependent diabetics attending a diabetic clinic provided an early morning urine sample (Albustix-negative) which was subjected to each of the three tests, and urinary albumin concentration (UA) was assayed by RIA. Tests were assessed in random order by two trained operators using a semiquantitative grading scale with 100% concordance between 10 observers. All test results greater than or equal to trace +ve were sufficiently sensitive (sensitivity greater than or equal to 90%) in detecting UA greater than 15 mg/l, but MAT exhibited a significantly reduced specificity (69%) and positive predictive value (58%). For a reference UA greater than 30 mg/l, LBT and SST results greater than or equal to trace +ve and MAT results greater than or equal to +ve showed a sensitivity of 100%, a specificity greater than 85% and a positive predictive value greater than 60%. Reagent shelf-life was shortest with LBT. SST involved centrifugation or filtration. Technical skill required was highest with LBT and lowest with MAT. Costs were slightly higher with LBT than SST and were not available for MAT.

Albuminuria↗
PubMed1988

Nutrient intake in insulin-dependent diabetic patients with incipient nephropathy.

The onset of diabetic nephropathy is characterized by subclinical elevation of urinary albumin excretion, so-called 'microalbuminuria' (M). Dietary assessments were carried out in 15 insulin-dependent diabetic patients with persistent M and an equal number with persistently normal albumin excretion. The groups were matched for sex, age, duration of diabetes, body mass index, insulin dose and glycosylated haemoglobin; there were no significant differences in systemic blood pressure, glomerular filtration rate, blood glucose and serum albumin concentrations between the groups; retinopathy was significantly more frequent in patients with M. Diabetics with persistent M were found to consume a significantly larger amount of fat (expressed as grams and percentage of total energy) and a significantly smaller percentage of total energy as carbohydrate than patients with normal albumin excretion; total dietary energy was larger in those with persistent M, but the difference was not significant. No significant differences were found in protein and fibre intakes between the groups. Our findings suggest that an excess in the dietary consumption of fat relative to carbohydrate might play an important role in the pathogenesis of early nephropathy in insulin-dependent diabetes mellitus. We emphasize the importance of careful attention to nutrient intake in the prevention and treatment of diabetic complications.

Adult↗
PubMed1987

The control of experimental Escherichia coli diarrhoea in calves by means of bacteriophages.

Seven phages highly active in vitro and in vivo against one or other of seven bovine enteropathogenic strains of Escherichia coli belonging to six different serotypes were isolated from sewage. Severe experimentally induced E. coli diarrhoea in calves could be cured by a single dose of 10(5) phage organisms. It could be prevented by doses as low as 10(2), by spraying the litter in the calf rooms with aqueous phage suspensions or simply by keeping the calves in uncleaned rooms previously occupied by calves whose E. coli infections had been treated with phage. Microbiological examinations of calves used in these experiments revealed that the phage organisms multiplied rapidly and profusely after gaining entry to the E. coli-infected small intestine, quickly reducing the E. coli to numbers that were virtually harmless. The only phage-resistant E. coli that emerged in the studies on calves infected with one or other of the seven E. coli strains were K-. These organisms were much less virulent than the K+ organisms from which they were derived and did not present a serious problem in calves given adequate amounts of colostrum. Infections produced by oral inoculation of a mixture of six strains of the E. coli could be controlled by administration of a pool of the six phages that were active against them but, in general, the control was less complete than that observed in the single-strain infections. K+ phage-resistant bacteria emerged in some of the calves used in these mixed infections and they were as virulent as their parent organisms; evidence from in vitro studies suggested that they might have arisen by genetic transfer between organisms of the different infecting strains. Infections produced by these K+ mutants and their parents could be controlled by the use of mutant phages derived from phages that were active on their parents. During the experiments with mixed E. coli infection, an extraneous phage active against one of the six E. coli strains suddenly appeared in calves kept in the same rooms. Microbiological examinations revealed that this phage was effectively controlling the multiplication of organisms of that particular strain of E. coli in the small intestines of the calves.

Animals↗
PubMed1987

Factors influencing the survival and multiplication of bacteriophages in calves and in their environment.

Seven phages were fairly susceptible in vitro to the lethal effect of acidified whey, more so than the enteropathogenic Escherichia coli strains on which they were active. The low acidity that prevailed in the abomasum contents of calves shortly after a milk feed had little harmful effect on orally administered organisms of these phages; they flooded into the small intestine. The high acidity that prevailed later was lethal to orally administered phage organisms; few entered the small intestine. The lethal effect could be counteracted by giving CaCO3 in the feed. Low concentrations of phage-neutralizing antibodies were found in some serum samples from human beings, cattle and pigs. Antibodies to one of the seven phages were common in the human samples and antibodies to another, phage B44/1, were common in the cattle and pig samples and in bovine colostrum. Phage B44/1 antibodies in a sample of colostral whey were destroyed at pH 3.25 or less. Giving colostrum containing phage B44/1 antibodies with CaCO3 to a calf greatly reduced the numbers of orally administered phage B44/1 organisms in its alimentary tract. Antibodies to another phage were induced in the serum of a calf suffering from E. coli diarrhoea by treating it with that phage. The phages were as susceptible as the E. coli strains to the lethal action of formaldehyde and sodium hypochlorite. In contrast to the E. coli strains, they were almost completely resistant to phenol and chloroxylenol. The in vitro virulence of 21 phages varied according to the temperature at which tests were performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Abomasum↗
PubMed1986

Assessment of new radioimmunoassay kit for determining urinary albumin at low concentrations: comparison with radial immunodiffusion.

The assay characteristics of a new radioimmunoassay kit for determining urinary albumin at low concentrations were studied. The sensitivity for urinary albumin was 2 mg/l, the analytical range 2 to 40 mg/l, and interassay coefficient of variation less than 12%. In a method comparison study entailing diabetic urine samples covering an albumin concentration of 2 to 150 mg/l the kit compared adequately with radial immunodiffusion (mean difference between methods = 2 mg/l; residual standard deviation = 4.6 mg/l), absolute variation between methods increasing with the concentration. The kit required much less skill than radial immunodiffusion but its capital and running cost were higher.

Albuminuria↗