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Biomedical subjects

R G Firth

Publications and source records attributed to R G Firth.

At least 19 recordsLinked to original sources
PubMed2003

Irish diabetes detection programme in general practice.

OBJECTIVES: To assess the prevalence of undiagnosed diabetes, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) in patients over the age of 40 years attending their general practitioner (GP) in Ireland, through opportunistic screening, using a three-step screening tool involving self-determined high-risk groups, random venous plasma glucose (RVPG) measurement and oral glucose tolerance tests. DESIGN: In participating general practices, 100 consecutive patients > 40 years, completed a screening questionnaire relating to diabetes-related symptoms and risk factors. Patients with previously diagnosed diabetes were not excluded from the study and the screening instrument included a question about known diabetes. Patients without known diabetes mellitus (DM) and with at least two risk factors and/or symptoms underwent a RVPG test. Those with an RVPG above 5.5 mmol/l underwent an oral glucose tolerance test. RESULTS: Forty-one practices returned 3821 questionnaires. The prevalence of Type 2 diabetes mellitus in the study population was 9.2% (353), of whom 23.5% (83) were previously undiagnosed. DM was detected on the basis of an RVPG >11.1 mmol/l in 0.8% (32) of the studied population. DM was detected on the basis of the oral glucose tolerance test in 1.3% (51) of the population. One per cent (39) had a fasting plasma glucose (FPG) > or = 7.0 mmol/l, 0.6% (24) had a 2-h >11.0 mmol/l and 0.3% (12) had both. Diabetes would not have been detected in 12 people had the 2-h test been omitted. The prevalence rate for IFG and/or IGT was 3.9% (148). Of the 103 patients with IGT, 83 (81%) would have been missed had the GTT been omitted. CONCLUSION: Opportunistic diabetes screening in general practice using a screening questionnaire followed by RVPG testing and GTT for those above 5.5 mmol/l is feasible, with a high participation rate. The use of GTTs rather than fasting glucose testing alone improves patient identification, in particular those with IGT who are at higher cardiovascular risk.

Adult↗
PubMed2000

Universal vs. risk factor-based screening for gestational diabetes mellitus: detection rates, gestation at diagnosis and outcome.

AIMS: Gestational diabetes mellitus (GDM) is associated with adverse maternal and fetal outcome. Screening for GDM is therefore recommended but the best screening method remains controversial. This prospective, randomized study compared a risk factor-based screening programme with a universally based one. METHODS: Subjects were randomized at booking to one of two groups: the risk factor group had a 3-h 100-g oral glucose tolerance test (OGTT) at 32 weeks if any risk factor for GDM was present; the universal group had a 50-g glucose challenge test performed and if their plasma glucose at 1 h was > or = 7.8 mmol/l, a formal 3-h 100-g OGTT was then performed. RESULTS: Universal screening detected a prevalence of GDM of 2.7%, significantly more than the 1.45% detected in the risk factor screened group (P<0.03). Universal screening facilitated earlier diagnosis than risk factor screening - mean gestation 30 +/- 2.6 weeks vs. 33 +/- 3.7 weeks (P<0.05). A higher rate of spontaneous vaginal delivery at term, and lower rates of macrosomia, Caesarean section, prematurity, pre-eclampsia and admission to neonatal intensive care unit were observed in the universally screened, early diagnosis group. CONCLUSIONS: Universal screening for GDM is superior to risk factor based screening-detecting more cases, facilitating early diagnosis and is associated with improved pregnancy outcome.

Blood Glucose↗
PubMed1999

Type 1 diabetes mellitus, coeliac disease, and lymphoma: a report of four cases.

INTRODUCTION: Patients with Type 1 diabetes mellitus have a high prevalence of coeliac disease, symptoms of which are often mild, atypical, or absent. Untreated coeliac disease is associated with an increased risk of malignancy, particularly of lymphoma. We describe four patients with Type 1 diabetes mellitus and coeliac disease who developed lymphoma. CASE REPORTS: Two patients were male and two female. In three patients, coeliac disease and lymphoma were diagnosed simultaneously. Enteropathy-associated T cell lymphoma occurred in two patients, Hodgkin's disease in one, and B cell lymphoma in one. Response to treatment was in general poor, and three patients died soon after the diagnosis of lymphoma was made. CONCLUSION: As the relative risk of lymphoma is reduced by a gluten-free diet, a high index of suspicion for coeliac disease should exist in all Type 1 diabetic patients with unexplained constitutional or gastrointestinal symptoms.

Adult↗
PubMed1998

Dobutamine stress echocardiography: false positive scans in proteinuric patients with type 1 diabetes mellitus at high risk of ischaemic heart disease.

Patients with Type 1 diabetes mellitus have an increased risk of ischaemic heart disease (IHD). When diabetes is complicated by nephropathy this risk is further increased and asymptomatic IHD is common. New techniques for non-invasive cardiac evaluation are now available and one of these, Dobutamine Stress Echocardiography (DSE), was studied in subjects with Type 1 DM and nephropathy who had no evidence of IHD. DSE was performed on 18 subjects (13 male, 5 female; mean age 37.8 +/- 3.4 years), diabetes duration 23.7 +/- 1.2 years and nephropathy diagnosed for 10.9 +/- 1.3 years. There were 7 (38%) positive scans-suggesting asymptomatic IHD; 16.7% of subjects studied had a significant arrhythmia. Coronary angiography was performed in 6 of the 7 subjects with positive DSEs and was positive in only 2. These results suggest that DSE has a high rate of false positive results in Type 1 DM patients suffering from nephropathy and may limit its usefulness in these subjects.

Adult↗
PubMed1992

The Wolfram syndrome: a primary neurodegenerative disorder with lethal potential.

We describe four cases of the Wolfram syndrome; a rare congenital syndrome characterised in it's complete form by diabetes mellitus, diabetes insipidus, optic atrophy, nerve deafness and dilatation of the urinary tract. All four of the cases described developed grand mal epilepsy in their second and third decades. Two of the cases developed progressive ataxia. There was one death due to status epilepticus. Absence of most of the corpus callosum and of the septum pellucidum was noted at autopsy. This pathological finding has not been reported previously in this syndrome. These cases highlight the neuro-degenerative aspects of the Wolfram syndrome. The literature on neurological aspects of the syndrome is reviewed.

Adult↗
PubMed1990

Metabolic effects of an insulin-like factor causing hypoglycaemia in a patient with a haemangiopericytoma.

We have studied a patient with fasting hypoglycaemia and skin lesions (sign of Leser-Trélat) related to a retroperitoneal haemangiopericytoma in whom removal of the tumour resulted in immediate cure of hypoglycaemia. Before removal of the tumour, severe fasting hypoglycaemia was associated with undetectable insulin and C-peptide levels. She required 16.9 mumol/kg/min (10.4 g/h) of glucose intravenously to prevent hypoglycaemia and endogenous glucose production (measured using tritiated glucose) was suppressed to 1.3 mumol/kg/min while the whole-body glucose utilization rate was elevated at 18.2 mumol/kg/min. After removal of the tumour both endogenous glucose production rate and utilization rate returned to normal (11.5 mumol/kg/min). Resting energy expenditure, measured by indirect calorimetry, was markedly elevated at 2109 kcal/day (161% of predicted) and fell to 1205 (97% of predicted) after the tumour was removed. Glucose oxidation was also enhanced at 8.5 mumol/kg/min and fell to 3.3 mumol/kg/min after removal of the tumour. Other metabolites and hormones measured, and their response to oral glucose, were all consistent with the presence of a circulating substance with similar properties to insulin. We conclude that her hypoglycaemia resulted primarily from suppression of endogenous glucose production but also from enhanced glucose utilization. These effects were the result of a circulating growth factor sharing many metabolic effects with insulin, but with a much greater effect on resting energy expenditure and glucose oxidation.

Adult↗
PubMed1989

Assessment of the postprandial pattern of glucose metabolism in nondiabetic subjects and patients with non-insulin-dependent diabetes mellitus using a simultaneous infusion of [2(3)H] and [3(3)H] glucose.

Glucose turnover determined with tritiated isotopes of glucose is subject to potential error due to glucose/glucose-6-phosphate cycling and/or cycling through glycogen. To determine the extent to which these processes alter the apparent pattern of postprandial glucose metabolism, we measured glucose turnover simultaneously with [2(3)H] glucose (an isotope that minimally cycles through glycogen but is extensively detritiated during glucose/glucose-6-phosphate cycling) and [3(3)H] glucose (an isotope that is not detritiated during glucose/glucose-6-phosphate cycling but can cycle through glycogen). Glucose turnover was measured in patients with non-insulin-dependent diabetes mellitus (NIDDM) and nondiabetic subjects both before and after ingestion of a carbohydrate meal isotopically with labeled [6(14)C] glucose. In the postabsorptive state hepatic glucose appearance was higher (P less than .05) when determined with [2(3)H] glucose than with [3(3)H] glucose in the diabetic patients, but not in the nondiabetic subjects. After glucose ingestion the integrated responses of glucose appearance, systemic entry of ingested glucose, and hepatic glucose release all were higher (P less than .05) when determined with [2(3)H] glucose compared to [3(3)H] glucose in both the diabetic and nondiabetic subjects. However, the absolute difference between glucose turnover measured with [2(3)H] and [3(3)H] glucose were similar in the diabetic and nondiabetic subjects. Both isotopes provided a similar assessment of postprandial carbohydrate metabolism, indicating that either isotope can be used with equal efficacy to compare postprandial carbohydrate metabolism in patients with NIDDM and nondiabetic subjects.

Adult↗
PubMed1988

Insulin: either alone or combined with oral hypoglycemic agents.

Non-insulin-dependent diabetes mellitus patients are those patients who do not require insulin for survival and do not have gestational, secondary, or malnutrition-related diabetes. They may require insulin to maintain good health. Therapy in NIDDM should attempt to reverse the coexisting defects of insulin deficiency and insulin resistance that lead to hepatic glucose over-production and diminished glucose tissue utilization. Both sulfonylureas and insulin can achieve near normal FPGs and HbA1c concentrations in mild to moderately severe NIDDM. Both can reduce insulin resistance and both increase insulin availability. Evidence exists, however, showing that prevention of post-prandial hyperglycemia, whose significance is unknown, may require soluble preprandial insulin. Treatment goals should be realistic and discussed with the patient. In younger patients, the aim should be to achieve normoglycemia, while in those who have other significant medical or social problems, or who are of advanced age, diabetic control may, out of necessity, need to be relaxed. At presentation a diet and exercise program should be initiated and the patient observed if clinically well. If diet fails to reduce the FPG below 108 mg/dl, additional therapy should be used. In mild to moderate NIDDM, sulfonylurea or basal insulin (given as once daily long- or intermediate-acting insulin) can be equally successful without the need for rigid dietary habits. More severe degrees of NIDDM or patients with sulfonylurea failure not caused by dietary indiscretion will require more complex insulin regimens. The socially dependent patient requiring insulin should have as simple a regimen as possible. The insulin-resistant patient undergoing surgery or with an intercurrent illness is most easily managed with a variable rate insulin infusion that allows prediction of subsequent subcutaneous insulin requirements. Combination insulin-sulfonylurea therapy should be reserved for patients failing to achieve acceptable glycemic control when insulin and sulphonylurea are used separately. It may improve control or lessen insulin requirements.

Diabetes Mellitus, Type 2↗
PubMed1987

The effects of hyperglycaemia on isotopic measurement of glucose utilisation using [2(3)H], [3(3)H] and [6(14)C] glucose in patients with type 1 (insulin-dependent) diabetes mellitus.

To determine whether hyperglycaemia alters the accuracy with which [2(3)H] and [3(3)H]glucose reflect glucose turnover measured with [6(14)C]glucose in patients with Type 1 (insulin-dependent) diabetes mellitus, glucose utilisation rates were measured during a simultaneous infusion of [2(3)H], [3(3)H] and [6(14)C]glucose after maintenance of normoglycaemia overnight and when glucose concentrations were clamped at 5.3, 7.5 and 9.7 mmol/l while insulin and glucagon concentrations were held constant. Glucose utilisation rates determined with all three isotopes were comparable in the diabetic patients at all glucose concentrations studied. On the other hand, glucose utilisation rates in nondiabetic subjects determined with [6(14)C]glucose were greater (p less than 0.01) than those determined with [3(3)H]glucose and lower (p less than 0.04) than those determined with [2(3)H]glucose during the 5.3, 7.5 and 9.7 mmol/l clamps. Nevertheless, glucose utilisation rates in the diabetic patients were lower (p less than 0.05) than those in the nondiabetic subjects for each glucose isotope. We conclude that hyperglycaemia does not alter the pattern of metabolism of [2(3)H] or [3(3)H]glucose in patients with Type 1 (insulin-dependent) diabetes mellitus.

Adult↗
PubMed1986

Effects of tolazamide and exogenous insulin on insulin action in patients with non-insulin-dependent diabetes mellitus.

To determine whether sulfonylureas and exogenous insulin have different effects on insulin action, we studied eight patients with non-insulin-dependent diabetes mellitus before and after three months of treatment with tolazamide and exogenous semisynthetic human insulin, using a randomized crossover design. Therapy with tolazamide and therapy with insulin resulted in similar improvement of glycemic control, as measured by a decrease in mean glycosylated hemoglobin (+/- SEM) from 9.4 +/- 0.7 percent to 7.7 +/- 0.5 percent with tolazamide and to 7.1 +/- 0.2 percent with exogenous insulin (P less than 0.01 for both comparisons). Therapy with either tolazamide or exogenous insulin resulted in a similar lowering (P less than 0.05) of postabsorptive glucose-production rates (from 2.3 +/- 0.1 to 2.0 +/- 0.2 and 1.8 +/- 0.1 mg per kilogram of body weight per minute, respectively) but not to normal (1.5 +/- 0.1 mg per kilogram per minute). Both tolazamide and exogenous insulin increased (P less than 0.05) glucose utilization at supraphysiologic insulin concentrations (from 6.2 +/- 0.7 to 7.7 +/- 0.6 mg per kilogram per minute with tolazamide and to 7.8 +/- 0.6 mg per kilogram per minute with exogenous insulin) to nondiabetic rates (7.9 +/- 0.5 mg per kilogram per minute). Neither agent altered erythrocyte insulin binding at physiologic insulin concentrations. We conclude that treatment with sulfonylureas or exogenous insulin results in equivalent improvement in insulin action in patients with non-insulin-dependent diabetes mellitus. Therefore, the choice between these agents should be based on considerations other than their ability to ameliorate insulin resistance.

Blood Glucose↗
PubMed1986

Postprandial hyperglycemia in patients with noninsulin-dependent diabetes mellitus. Role of hepatic and extrahepatic tissues.

Patients with noninsulin-dependent diabetes mellitus (NIDDM) have both preprandial and postprandial hyperglycemia. To determine the mechanism responsible for the postprandial hyperglycemia, insulin secretion, insulin action, and the pattern of carbohydrate metabolism after glucose ingestion were assessed in patients with NIDDM and in matched nondiabetic subjects using the dual isotope and forearm catheterization techniques. Prior to meal ingestion, hepatic glucose release was increased (P less than 0.001) in the diabetic patients measured using [2-3H] or [3-3H] glucose. After meal ingestion, patients with NIDDM had excessive rates of systemic glucose entry (1,316 +/- 56 vs. 1,018 +/- 65 mg/kg X 7 h, P less than 0.01), primarily owing to a failure to suppress adequately endogenous glucose release (680 +/- 50 vs. 470 +/- 32 mg/kg X 7 h, P less than 0.01) from its high preprandial level. Despite impaired suppression of endogenous glucose production during a hyperinsulinemic glucose clamp (P less than 0.001) and decreased postprandial C-peptide response (P less than 0.05) in NIDDM, percent suppression of hepatic glucose release after oral glucose was comparable in the diabetic and nondiabetic subjects (45 +/- 3 vs. 39 +/- 2%). Although new glucose formation from meal-derived three-carbon precursors (53 +/- 3 vs. 40 +/- 7 mg/kg X 7 h, P less than 0.05) was greater in the diabetic patients, it accounted for only a minor part of this excessive postprandial hepatic glucose release. Postprandial hyperglycemia was exacerbated by the lack of an appropriate increase in glucose uptake whether measured isotopically or by forearm glucose uptake. Thus as has been proposed for fasting hyperglycemia, excessive hepatic glucose release and impaired glucose uptake are involved in the pathogenesis of postprandial hyperglycemia in patients with NIDDM.

C-Peptide↗
PubMed1986

Assessment of insulin action in insulin-dependent diabetes mellitus using [6(14)C]glucose, [3(3)H]glucose, and [2(3)H]glucose. Differences in the apparent pattern of insulin resistance depending on the isotope used.

To determine whether [2(3)H], [3(3)H], and [6(14)C]glucose provide an equivalent assessment of glucose turnover in insulin-dependent diabetes mellitus (IDDM) and nondiabetic man, glucose utilization rates were measured using a simultaneous infusion of these isotopes before and during hyperinsulinemic euglycemic clamps. In the nondiabetic subjects, glucose turnover rates determined with [6(14)C]glucose during insulin infusion were lower (P less than 0.02) than those determined with [2(3)H]glucose and higher (P less than 0.01) than those determined with [3(3)H]glucose. In IDDM, glucose turnover rates measured with [6(14)C]glucose during insulin infusion were lower (P less than 0.05) than those determined with [2(3)H]glucose, but were not different from those determined with [3(3)H]glucose. All three isotopes indicated the presence of insulin resistance. However, using [3(3)H]glucose led to the erroneous conclusion that glucose utilization was not significantly decreased at high insulin concentrations in the diabetic patients. [6(14)C] and [3(3)H]glucose but not [2(3)H]glucose indicated impairment in insulin-induced suppression of glucose production. These results indicate that tritiated isotopes do not necessarily equally reflect the pattern of glucose metabolism in diabetic and nondiabetic man.

Adult↗
PubMed1986

Effects of hyperglycemia on glucose production and utilization in humans. Measurement with [23H]-, [33H]-, and [614C]glucose.

Studies with tritiated isotopes of glucose have demonstrated that hyperglycemia per se stimulates glucose utilization and suppresses glucose production in humans. These conclusions rely on the assumption that tritiated glucose provides an accurate measure of glucose turnover. However, if in the presence of hyperglycemia the isotope either loses its label during "futile" cycling or retains its label during cycling through glycogen, then this assumption is not valid. To examine this question, glucose utilization and glucose production rates were measured in nine normal subjects with a simultaneous infusion of [23H]glucose, an isotope that may undergo futile cycling but does not cycle through glycogen; [614C]glucose, an isotope that may cycle through glycogen but does not futile cycle; and [33H]glucose, an isotope that can both undergo futile cycling and cycle through glycogen. In the postabsorptive state at plasma glucose concentration of 95 mg X dl-1, glucose turnover determined with [614C]glucose (2.3 +/- 0.1 mg X kg-1 X min-1) was greater than that determined with [33H]glucose (2.1 +/- 0.1 mg X kg-1 X min-1, P = 0.002) and slightly less than that determined with [23H]glucose (2.7 +/- 0.2 mg X kg-1 X min-1, P = 0.08). Plasma glucose was then raised from 95 to 135 to 175 mg X dl-1 while insulin secretion was inhibited, and circulating insulin, glucagon, and growth hormone concentrations were maintained constant by infusion of these hormones and somatostatin. Glucose production and utilization rates determined with [614C]glucose continued to be less than those determined with [23H]glucose and greater than those seen with [33H]glucose.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Development of hypercalcemic hyperparathyroidism after long-term phosphate supplementation in hypophosphatemic osteomalacia. Report of two cases.

Orally administered phosphate supplements are the mainstay of therapy for hypophosphatemic osteomalacia of diverse causes and are generally believed to be free from harmful side effects. Two cases are reported, however, in which long-term therapy (14 and 10 years, respectively) resulted in hypercalcemic hyperparathyroidism associated with surgically proved adenomatous hyperplasia. This complication occurred despite concomitant treatment with pharmacologic doses of vitamin D. Thus, long-term oral phosphate therapy can produce tertiary hyperparathyroidism in susceptible patients.

Adult↗