Search PubMed⌕ Search

Biomedical subjects

M A Crook

Publications and source records attributed to M A Crook.

71 records · Page 4Linked to original sources
PubMed1995

Serum sialic acid concentration and coronary heart disease in NIDDM.

OBJECTIVE--To examine the association between serum sialic acid concentrations and coronary heart disease (CHD) in a cross-sectional study of non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS--NIDDM patients (n = 145) attending a diabetic clinic were studied. CHD status was assessed by questionnaire and electrocardiogram coding, and potential risk factor assessment included measurement of fasting serum lipid and lipoprotein concentrations, blood pressure, and urinary albumin excretion rate (AER). RESULTS--Male NIDDM patients with CHD had a higher serum sialic acid level than those without CHD: 2.56 (2.24, 2.72) mmol/l vs. 2.24 (2.18, 2.30) mmol/l, P = 0.01, mean (95% confidence interval). They were also older, had a longer duration of diabetes, had a higher AER, had higher total triglyceride, very-low-density lipoprotein triglyceride and cholesterol, and lipoprotein(a) concentrations, and had a lower apolipoprotein A1 concentration. In an age adjusted multiple lipoprotein(a), hypercholesterolemia, and hypertension were associated with CHD. In women, only hypertension treatment was associated with CHD. CONCLUSIONS--There is a strong univariate association between elevated serum sialic acid and CHD in men (but not women) with NIDDM.

Adult↗
PubMed1994

Electrokinetic properties of human cryopreserved platelets.

A method for the cryopreservation of human platelets with glycerol/glucose is described which was a simplified modification of the method of Dayian and Pert (1979). The effect of cryoinjury of the platelet surface membrane was investigated by studying the surface electrokinetic properties of the platelet. A significant increase in platelet electrophoretic mobility was found after cryopreservation. The fresh platelets had a mean electrophoretic mobility of 1.04 +/- 0.05 microns s-1 V-1 cm-1 and cryopreserved platelets 1.18 +/- 0.05 microns s-1 V-1 cm-1, P < 0.05. However, the total platelet sialic acid of fresh platelets was 62.5 +/- 5.6 nmol 10(-9) platelets compared to 47.2 +/- 4.6 nmol 10(-9) platelets after cryopreservation, P < 0.001. Similarly, the neuraminidase-labile sialic acid was 26.4 +/- 4.3 nmol 10(-9) platelets for fresh platelets and 17.6 +/- 4.0 nmol 10(-9) platelets after cryopreservation, P < 0.001. Using polyacrylamide gel electrophoresis with Western blotting, we showed a reduction in the platelet glycoprotein Gp Ib after cryopreservation, this was confirmed by using crossed immunoelectrophoresis. Electron microscopy revealed a significant change in platelet morphology after the cryopreservation procedure with disruption of the platelet membrane and also platelet shape change. These features may explain the changes in platelet electrokinetic properties.

Blood Platelets↗
PubMed1994

Iron status, movement disorders, and acute phase response in elderly psychiatric patients.

The previously reported relation between iron deficiency and movement disorders was studied in a population with a high prevalence of both problems. There was no evidence of a direct statistical relation between iron deficiency and movement disorders. Significant associations were, however, found between movement disorders and features of the acute phase response to physiological stress. Indices of iron status are known to be affected by the acute phase response and it is suggested that the previously reported abnormalities in iron status may be secondary to this.

Acute-Phase Reaction↗
PubMed1994

Serum total sialic acid and acute phase proteins in elderly subjects.

Serum total sialic acid has gained recent interest as a cardiovascular risk factor. We measured serum total sialic acid and three acute phase proteins; C-reactive protein, alpha 1-antichymotrypsin and alpha 1-acid glycoprotein in 37 geriatric patients (age 80.1 +/- 7.0 years) and 50 younger subjects (age 40.3 +/- 11.4 years). Serum total sialic acid was higher in the geriatric subjects 2.41 +/- 0.39 mmol/l versus 2.04 +/- 0.35 mmol/l, P < 0.04. Serum alpha 1-acid glycoprotein, alpha 1-antichymotrypsin and C-reactive protein were also elevated in the geriatric patients; serum alpha 1-acid glycoprotein being 1.16 +/- 0.32 g/l versus 0.41 +/- 0.28 g/l, P < 0.0001, serum alpha 1-antichymotrypsin being 0.80 +/- 0.20 g/l versus 0.52 +/- 0.10 g/l, P < 0.0001 and serum C-reactive protein being 9.71 +/- 21.0 mg/l versus 4.73 +/- 1.30 mg/l, P < 0.04. There was a correlation with serum total sialic acid and serum alpha 1-acid glycoprotein and alpha 1-antichymotrypsin in the geriatric subjects and with alpha 1-acid glycoprotein, alpha 1-antichymotrypsin and C-reactive protein in the younger group.

Acute-Phase Proteins↗
PubMed1994

Serum sialic acid, a risk factor for cardiovascular disease, is increased in IDDM patients with microalbuminuria and clinical proteinuria.

OBJECTIVE: An elevated serum sialic acid concentration has recently been shown to be a potent cardiovascular risk factor in the general population. Because clinical proteinuria is associated with a high frequency of cardiovascular disease, and because microalbuminuria predicts the development of renal and cardiovascular disease in diabetes, we investigated whether serum sialic acid levels are increased in insulin-dependent diabetes mellitus (IDDM) patients with microalbuminuria or clinical proteinuria. RESEARCH DESIGN AND METHODS: We studied 23 patients with IDDM who had a normal urinary albumin excretion rate, 23 patients who had microalbuminuria, and 23 patients with clinical proteinuria. The patients were matched for age, sex, duration of diabetes, GHb levels, and body mass index (BMI). Fasting blood samples were taken for measurement of sialic acid, cholesterol, triglyceride, creatinine, and GHb. RESULTS: Serum sialic acid was significantly higher in the microalbuminuric patients compared with the normoalbuminuric group (mean +/- SD: 1.93 +/- 0.26 vs. 1.76 +/- 0.27 mM, P < 0.01). Moreover, serum sialic acid was also significantly higher in the group with clinical proteinuria compared with the microalbuminuric patients (2.34 +/- 0.24 vs. 1.93 +/- 0.26 mM, P < 0.001). Serum sialic acid was not related independently to age, BMI, diabetes duration, GHb, blood pressure, serum cholesterol, triglyceride, or creatinine concentration in any of the diabetic groups. CONCLUSIONS: These observations suggest that the serum sialic acid concentration is raised in IDDM patients with both microalbuminuria and clinical proteinuria and may play a role as a cardiovascular risk factor or disease marker in these conditions.

Adult↗
PubMed1994

Hypophosphataemia and hypokalaemia in patients with hypomagnesaemia.

Experimental data suggest an association between hypomagnesaemia and hypokalaemia, and also with hypophosphataemia, but there have been few large studies using clinical results to study the prevalence of hypophosphataemia and/or hypokalaemia in patients with hypomagnesaemia. Our results show a two-fold increase in the prevalence of hypophosphataemia (plasma phosphate concentration < or = 0.80 mmol/l) in patients with hypomagnesaemia (plasma magnesium level < or = 0.70 mmol/l) compared with patients without this condition, and a six-fold increase in hypokalaemia (plasma potassium < or = 3.5 mmol/l). A triology consisting of hypomagnesaemia, hypophosphataemia and hypokalaemia is also described, which was found in 8% of patients with hypomagnesaemia and 17% of patients with severe hypomagnesaemia (plasma magnesium < or = 0.50 mmol/l). Patients most susceptible to this phenomenon include those in intensive therapy, post-operative patients, those with sepsis being treated with aminoglycosides, and oncology patients receiving chemotherapy.

Humans↗
PubMed1993

Serum sialic acid and acute phase proteins in type 1 and type 2 diabetes mellitus.

Serum sialic acid is a risk factor for cardiovascular disease in the general population. Serum total sialic acid concentrations were therefore measured in 20 type 1 diabetic patients and in 20 age- and sex-matched non-diabetic subjects. Serum sialic acid were not significantly different in the type 1 diabetic patients and the normal subjects (2.00 +/- 0.37 vs. 1.98 +/- 0.67 mmol/l), but was significantly correlated with serum total cholesterol (r = 0.55, P < 0.02) and serum triglyceride concentration (r = 0.63, P < 0.01) in the type 1 diabetic patients. There was no relationship of sialic acid levels to age, duration of diabetes, smoking, body mass index, systolic or diastolic blood pressure, plasma glucose, serum fructosamine, or daily insulin dosage. Six of the type 1 diabetic patients with retinopathy had higher total serum sialic acid concentrations than those patients without retinopathy (2.38 +/- 0.33 vs. 1.85 +/- 0.26 mmol/l, P < 0.01). A further study of 16 type 1 and 16 type 2 diabetic patients matched for serum fructosamine and blood glucose concentrations and without tissue complications showed that the serum total sialic acid concentration was significantly higher in the type 2 diabetic patients compared with the type 1 patients (2.32 +/- 0.41 vs. 1.84 +/- 0.24 mmol/l, P < 0.001). Although the serum concentrations of the non-sialylated acute phase protein, C-reactive protein, was higher in type 2 than type 1 diabetes, sialylated acute phase protein levels did not explain differences in serum total sialic acid in diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute-Phase Proteins↗
PubMed1993

Elevated serum sialic acid concentration in NIDDM and its relationship to blood pressure and retinopathy.

OBJECTIVE: In view of the possible link between serum sialic acid and cardiovascular disease in the general population, we investigated whether serum total and lipid-associated sialic concentrations are elevated in NIDDM patients compared with normal subjects. We also investigated how sialic acid levels relate to glycemic control, blood pressure, microalbuminuria, retinopathy, and serum lipid levels. RESEARCH DESIGN AND METHODS: We selected 20 NIDDM patients at random and matched them for age and sex with 20 normal subjects. The patients also had a similar BMI as the control subjects. A first morning blood sample was taken for sialic acid, glucose, fructosamine, and lipid analysis, as was a first morning urine sample for assessment of microalbuminuria. Retinopathy was assessed by fundoscopy. RESULTS: Both total and lipid-associated sialic acid levels were elevated in the NIDDM patients compared with control subjects (mean +/- SD, total: 0.74 +/- 0.11 vs. 0.60 +/- 0.22 g/L, P < 0.02; lipid-associated: 0.18 +/- 0.04 vs 0.12 +/- 0.04 g/L, P < 0.001). Total serum sialic acid was correlated with systolic blood pressure (r = 0.58, P < 0.01) and diastolic blood pressure (r = 0.58, P < 0.02). There was no significant relationship of total sialic acid with age, duration of diabetes, BMI, microalbuminuria, serum triglyceride, blood glucose, or serum fructosamine. A relationship of lipid-associated sialic acid levels and systolic blood pressure did not reach significance (P = 0.09). In 9 patients with background retinopathy with or without maculopathy, the total serum sialic acid concentration was higher than in those without retinopathy (0.81 +/- 0.09 vs. 0.69 +/- 0.10 g/L, P < 0.008). Lipid-associated sialic acid levels were similar in those with and without retinopathy. (The conversion factor for standard units to SI units is 1 gL = 3.2 mM.) CONCLUSIONS: Total serum sialic acid levels were significantly elevated in a relatively small group of NIDDM patients and were correlated with hypertension and retinopathy. A larger study of circulating sialic acid concentrations as a risk factor for the development or marker of diabetic angiopathy is therefore justified.

Albuminuria↗
PubMed1993

Serum sialic acid enzymatic assay based on microtitre plates: application for measuring capillary serum sialic acid concentrations.

We have adapted a commercially-available kit for the enzymatic determination of sialic acid so that the reaction can be carried out in microtitre wells and the coloured end product quantitated on an ELISA plate reader. The small volume of serum used allows sialic acid to be measured in capillary blood samples. The assay was based on release of sialic acid from glycoconjugates by neuraminidase, cleavage of sialic acid by N-acetyl neuraminic acid aldolase to pyruvate, and then oxidation of pyruvate to hydrogen peroxide by pyruvate oxidase. Hydrogen peroxide was determined by the red product formed in the presence of peroxidase, 4-aminoantipyrine and N-ethyl-N-2-hydroxyethyl-3-toluidine. The assay was linear to at least 10 mmol/l and unaffected by haemolysis, and by the addition of glucose, 3-hydroxybutyrate, bilirubin and pyruvate. Capillary serum sialic acid concentrations were not significantly different from simultaneously measured venous serum sialic acid levels. Self-collected capillary blood samples were obtained from healthy subjects over 6 h during the day. No variations in serum sialic acid concentrations were found in response to a meal. We conclude that this micro-adaptation of a specific sialic acid assay will be suitable for epidemiological surveys of serum sialic acid collected by patients and normal subjects.

Biomarkers↗
PubMedDate not supplied

The importance of the refeeding syndrome.

In this review we discuss the refeeding syndrome. This potentially lethal condition can be defined as severe electrolyte and fluid shifts associated with metabolic abnormalities in malnourished patients undergoing refeeding, whether orally, enterally, or parenterally. It can be associated with significant morbidity and mortality. Clinical features are fluid-balance abnormalities, abnormal glucose metabolism, hypophosphatemia, hypomagnesemia, and hypokalemia. In addition, thiamine deficiency can occur. We describe which patient groups are more at risk for this syndrome and the clinical management of the condition.

Body Fluids↗