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Biomedical subjects

Eric S Kilpatrick

Publications and source records attributed to Eric S Kilpatrick.

18 recordsLinked to original sources

The effect of thyroid dysfunction on N-terminal pro-B-type natriuretic peptide concentrations.

BACKGROUND: B-type natriuretic peptides and N-terminal pro-B-type natriuretic peptides (NT-proBNP) have been suggested as being useful for the diagnosis of congestive heart failure. We have shown previously that changes in thyroid function are associated with changes in concentrations of other low molecular weight molecules. Therefore, the aim of this study was to assess whether similar changes occurred with NT-proBNP concentrations following treatment of thyroid dysfunction. METHODS: Seventeen patients (12 female, 5 male, age range 24-77 years) with newly diagnosed hypothyroidism and 21 patients (16 female, 5 male, age range 21-66 years) with newly diagnosed hyperthyroidism had NT-proBNP measured at baseline and when they subsequently became euthyroid. RESULTS: NT-proBNP levels were not significantly different in the hyperthyroid group from the hypothyroid, either before (P = 0.706) or after treatment to euthyroidism (P = 0.170). The hypothyroid group showed a rise in NT-proBNP after treatment (P < 0.001). There was a marginally significant fall in the NT-proBNP levels in the hyperthyroid group (P = 0.05). However, these changes were within the expected wide range of biological variability of NT-proBNP shown in earlier studies. CONCLUSIONS: Hypothyroidism alters NT-proBNP concentrations, but the magnitude of this effect may be lost in the wide biological variability of natriuretic peptides and this statistically significant finding is not likely to be of clinical relevance.

Adult↗

The LH/FSH ratio has little use in diagnosing polycystic ovarian syndrome.

BACKGROUND: The luteinizing hormone/follicle stimulating hormone (LH/FSH) ratio is often requested to help diagnose polycystic ovarian syndrome (PCOS) despite a recent consensus recommending against its use. This study aimed to compare the variability of the LH/FSH ratio in PCOS with that of normal menstruating women over a full cycle in order to establish the diagnostic utility, or otherwise, of the test. METHODS: Twelve women with PCOS and 11 matched controls had blood collected at four-day intervals on 10 consecutive occasions over a complete menstrual cycle. RESULTS: The median LH/FSH ratio for individual subjects did not differ significantly between the PCOS and the non-affected group (1.6 versus 1.2, P = 0.14). Only 7.6% of samples from PCOS patients had an LH/FSH ratio above three, compared with 15.6% of samples from normal subjects. CONCLUSION: This study confirms that measurement of the LH/FSH ratio is of limited use in the diagnosis of PCOS.

Adult↗

Use of haemolysis index to estimate potassium concentration in in-vitro haemolysed serum samples.

BACKGROUND: It has been advocated that measuring the haemoglobin concentration in a haemolysed sample can be used to correct the potassium concentration. However, estimation of the degree of potassium adjustment has not been validated with patient-derived data. This study aimed to ascertain the relationship between haemolysis and potassium increment using patient samples. METHODS: A total of 35 hospital patients (16 male, 19 female; median age 73 years, inter-quartile range 45-83 years) for whom haemolysed samples were repeated within 24 h were included in the study. The difference between potassium in the haemolysed and non-haemolysed repeat sample was correlated with the serum haemolysis index measured on a Beckman Synchron LX20PRO. RESULTS: The linear relationship derived for patient samples showed a potassium increase of approximately 0.16 mmol/L for each increment in the haemolysis index. However, Bland-Altman statistics in the patient-derived model showed the variability (95% limit of agreement) in predicted potassium concentration to be +/-0.4 mmol/L. CONCLUSIONS: The magnitude of the relationship using authentic patient data with the Beckman LX20PRO haemolysis index is in keeping with previously described relationships. Use of the haemolysis index on the Beckman LX20PRO to predict potassium concentration in haemolysed samples is not sufficiently accurate to obviate the need for repeat analysis, but can be used to prioritise the need for urgent repeat analysis.

Aged↗

The effect of glucose variability on the risk of microvascular complications in type 1 diabetes.

OBJECTIVE: It is not known whether glycemic instability may confer a risk of microvascular complications that is in addition to that predicted by the mean blood glucose (MBG) value alone. This study has analyzed data from the Diabetes Control and Complications Trial (DCCT) to assess the effect of glucose variability on the risk of retinopathy and nephropathy in patients with type 1 diabetes. RESEARCH DESIGN AND METHODS: Pre- and postprandial seven-point glucose profiles were collected quarterly during the DCCT in 1,441 individuals. The mean area under the curve glucose and the SD of glucose variability within 24 h and between visits were compared with the risk of retinopathy and nephropathy, having adjusted for age, sex, disease duration, treatment group, prevention cohort, and phase of treatment. RESULTS: Multivariate Cox regression showed that within-day and between-day variability in blood glucose around a patient's mean value has no influence on the development or progression of either retinopathy (P = 0.18 and P = 0.72, respectively) or nephropathy (P = 0.32 and P = 0.57). Neither preprandial (P = 0.18) nor postprandial (P = 0.31) glucose concentrations preferentially contribute to the probability of retinopathy. CONCLUSIONS: This study has shown that blood glucose variability does not appear to be an additional factor in the development of microvascular complications. Also, pre- and postprandial glucose values are equally predictive of the small-vessel complications of type 1 diabetes.

Adolescent↗

Hypopituitarism presenting as a mixed hyperlipidaemia.

A case report is presented of a 37-year-old man who, largely by chance, was found to have a marked mixed hyperlipidaemia. As a teenager he had been treated for apparent idiopathic growth hormone deficiency, but had also never developed secondary sexual characteristics. Pituitary hormone measurement was now consistent with hypopituitarism and magnetic resonance imaging showed hypoplasia of his pituitary stalk as the likely cause. His hyperlipidaemia improved after appropriate hormone replacement. He thus appears to have had a mixed hyperlipidaemia secondary to hypopituitarism, which was secondary to a pituitary stalk abnormality, which in turn may have been associated to the trauma surrounding his normal breech delivery.

Adult↗

Tumour markers: their use and misuse by clinicians.

BACKGROUND: Several guidelines exist on the appropriate use of serum tumour markers in the management of patients with cancer. This study audited tumour marker requesting against these guidelines in a busy teaching hospital over a 12-month period. METHODS: All marker requests from 1 April 2001 to 31 March 2002 were collected using the laboratory computer. From one 24-h period, the case notes from all hospital requests [excluding prostate-specific antigen (PSA)] were examined. RESULTS: Tumour marker workload increased by 125% from 1997-98 to 2001-02. Of 27 323 tumour marker requests, 7166 were from general practice, 2312 were requested on hospital admission before further investigation, 612/3636 of CA125 and 98/374 of CA15.3 requests were on men and 12/11585 PSA requests on women. Of 34 case notes examined, 18 had tumour markers measured before biopsy and only nine after. Of 19 patients with 'normal' markers, one had malignancy on biopsy and, of 15 with one or more raised markers, four had normal biopsies. CONCLUSIONS: Tumour marker workload is rapidly increasing. Tumour markers are frequently and inappropriately requested, either because they are on patients of the wrong sex, or because they are taken before a cancer diagnosis is reached. Results from these tests can be falsely reassuring or unduly alarming.

Aged↗

Beneficial effects of soy phytoestrogen intake in postmenopausal women with type 2 diabetes.

OBJECTIVE: Phytoestrogen consumption has been shown to reduce risk factors for cardiovascular disease. Type 2 diabetes confers an adverse cardiovascular risk profile particularly in women after menopause. The aim of this study was to determine whether a dietary supplement with soy protein and isoflavones affected insulin resistance, glycemic control, and cardiovascular risk markers in postmenopausal women with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 32 postmenopausal women with diet-controlled type 2 diabetes completed a randomized, double blind, cross-over trial of dietary supplementation with phytoestrogens (soy protein 30 g/day, isoflavones 132 mg/day) versus placebo (cellulose 30 g/day) for 12 weeks, separated by a 2-week washout period. RESULTS: Compliance with the dietary supplementation was >90% for both treatment phases. When compared with the mean percentage change from baseline seen after 12 weeks of placebo, phytoestrogen supplementation demonstrated significantly lower mean values for fasting insulin (mean +/- SD 8.09 +/- 21.9%, P = 0.006), insulin resistance (6.47 +/- 27.7%, P = 0.003), HbA(1c) (0.64 +/- 3.19%, P = 0.048), total cholesterol (4.07 +/- 8.13%, P = 0.004), LDL cholesterol (7.09 +/- 12.7%, P = 0.001), cholesterol/HDL cholesterol ratio (3.89 +/- 11.7%, P = 0.015), and free thyroxine (2.50 +/- 8.47%, P = 0.004). No significant change occurred in HDL cholesterol, triglycerides, weight, blood pressure, creatinine, dehydroepiandrosterone sulfate, androstenedione, and the hypothalamic-pituitary-ovarian axis hormones. CONCLUSIONS: These results show that dietary supplementation with soy phytoestrogens favorably alters insulin resistance, glycemic control, and serum lipoproteins in postmenopausal women with type 2 diabetes, thereby improving their cardiovascular risk profile.

Blood Glucose↗

Biological variation of homeostasis model assessment-derived insulin resistance in type 2 diabetes.

OBJECTIVE: Individuals with type 2 diabetes are particularly vulnerable to cardiovascular disease. Insulin resistance is a major determinant of this increased risk and is a potential therapeutic target. This study was undertaken to establish the natural biological variation of insulin resistance in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: The biological variation of insulin resistance was assessed by measuring insulin resistance at 4-day intervals on 10 consecutive occasions in 12 postmenopausal women with diet-controlled type 2 diabetes and in 11 weight- and age-matched postmenopausal women without type 2 diabetes. Insulin resistance was derived using the homeostasis model assessment for insulin resistance (HOMA-IR) method. RESULTS: The distribution of HOMA-IR was log Gaussian in the type 2 diabetic study group and Gaussian in the control group. The HOMA-IR in the type 2 diabetic group was significantly greater than that of the control group (mean +/- SD: 4.33 +/- 2.3 vs. 2.11 +/- 0.79 units, P = 0.001). After accounting for analytical variation, the mean intraindividual variation was also substantially greater in the type 2 diabetic group than in the control group (mean 1.05 vs. 0.15, P = 0.001). Consequently, at any level of HOMA-IR, a subsequent sample must increase by >90% or decrease by >47% to be considered significantly different from the first. CONCLUSIONS: HOMA-IR is significantly greater and more variable for individuals with type 2 diabetes. Therefore, this inherent variability needs to be accounted for in studies evaluating therapeutic reduction of HOMA-IR in this group.

Diabetes Mellitus, Type 2↗