Biomedical subjects

Brian M Frier

Publications and source records attributed to Brian M Frier.

22 records · Page 2Linked to original sources

PubMed2003

Moderate hypoglycemia impairs multiple memory functions in healthy adults.

The effects of acute insulin-induced hypoglycemia on short-term, delayed, and working memory were examined in healthy adults. A hyperinsulinemic glucose clamp was used to maintain arterialized blood glucose at either 4.5 (euglycemia) or 2.5 (hypoglycemia) mmol/L on 2 separate occasions in 16 healthy volunteers. Tests of immediate and delayed verbal memory, immediate and delayed visual memory, and working memory were administered during each experimental condition. All memory systems were impaired during acute hypoglycemia, with working memory and delayed memory being particularly susceptible. These findings are informative concerning the metabolic basis of adequate memory function and are of practical importance to people with insulin-treated diabetes, in whom hypoglycemia is common.

Adult↗

PubMed2002

Hypoglycaemic valleys: an under-recognised problem in type 2 diabetes?

In the treatment of type 2 diabetes, mild (self-treated) hypoglycaemia is associated with some oral hypoglycaemic agents and with insulin, but is perceived to be uncommon; severe hypoglycaemia (requiring external help) is thought to be rare. Ageing per se modifies the counterregulatory (CR) hormonal and symptomatic responses to hypoglycaemia and alters the glycaemic thresholds at which these occur. In type 2 diabetes, subtle CR hormonal deficiencies occur, and the glycaemic thresholds are set at higher blood glucose levels compared with non-diabetic subjects or people with type 1 diabetes. When significant insulin deficiency occurs, CR hormonal deficiencies appear, and glycaemic thresholds are modified when glycaemic control is improved with insulin therapy. Although symptomatic hypoglycaemia is reported to be uncommon in sulphonylurea-treated type 2 diabetes, its frequency may be underestimated; severe hypoglycaemia is rare. In insulin-treated type 2 diabetes accurate data of the frequency of hypoglycaemia are difficult to obtain, but an annual prevalence of 30 to 40% has been recorded for mild hypoglycaemia in clinical trials and 0.5 to 2.3% for severe hypoglycaemia. The true overall frequencies may be much higher, and rise with increasing duration of insulin therapy, duration of diabetes, and age. Patients with type 2 diabetes with progressive pancreatic beta cell failure increasingly resemble those with type 1 diabetes. The syndrome of counterregulatory hormonal deficiency may develop, but impaired awareness of hypoglycaemia is uncommon.

Age Factors↗

PubMedDate not supplied

The symptoms of hyperglycaemia in people with insulin-treated diabetes: classification using principal components analysis.

BACKGROUND AND AIMS: People with insulin-treated diabetes commonly experience symptoms of hyperglycaemia, but the nature of these symptoms and their origins are poorly understood. The aims of this study were (1) to identify and classify the symptoms of hyperglycaemia experienced by people with insulin-treated diabetes and (2) to identify patient characteristics associated with intensity of, and glycaemic threshold for, glycaemic symptoms. METHODS: Common hyperglycaemic symptoms were identified from preliminary interviews. Eighteen symptoms were used in a questionnaire. Four hundred participants estimated the intensities with which they experienced these symptoms during hyperglycaemia. Principal components analysis (PCA) was used to examine correlations between symptoms. Associations between symptom intensity, glycaemic threshold, and other characteristics were examined with multiple regression. RESULTS: In total, 361 participants (90.2%) reported experiencing hyperglycaemic symptoms. PCA suggested four symptom groupings: (1) feeling tense, irritability, restlessness, poor concentration (agitation) (2) thirst, dry mouth, need to urinate, not feeling right, sweet/funny taste, weakness (osmotic) (3) dizziness, blurred vision, light-headedness, weakness (neurological) (4) headache, nausea (malaise). Mean symptom intensity was associated with younger age. The median (range) estimated blood glucose threshold for symptom onset was 15 (8-30) mmol/L; there was a weak tendency for this threshold to be elevated in people who had impaired hypoglycaemia awareness. CONCLUSIONS: People with insulin-treated diabetes commonly reported symptoms associated with hyperglycaemia. PCA separated these into four groups. Osmotic symptoms appear to be specific to hyperglycaemia; symptoms in the other groups may suggest underlying physiological mechanisms, but are relatively non-specific. Symptoms are more intense in younger people and may be reported at lower blood glucose concentrations in people with normal awareness of hypoglycaemia.

Adolescent↗

PubMedDate not supplied

Nocturnal hypoglycemia: clinical manifestations and therapeutic strategies toward prevention.

OBJECTIVE: To review the features of nocturnal hypoglycemia and various preventive strategies. METHODS: We discuss the physiologic changes, the potential precipitating factors, the immediate and long-term effects, and the currently available options for treatment of nocturnal hypoglycemia in patients with diabetes. RESULTS: Nocturnal hypoglycemia is common in patients with type 1 diabetes and is usually asymptomatic. Nocturnal hyperinsulinemia frequently occurs with insulin therapy, and although blood glucose levels are often low during sleep, they are seldom measured routinely. Almost 50% of all episodes of severe hypoglycemia occur at night during sleep. Such episodes can cause convulsions and coma and have been implicated as a precipitating factor in cardiac arrhythmias resulting in sudden death--the "dead-in-bed syndrome." Nocturnal hypoglycemia seems to have no immediate detrimental effect on cognitive function; however, on the following day, mood and well-being may be adversely affected. Recurrent exposure to nocturnal hypoglycemia may impair cognitive function; other substantial long-term morbidity includes the development of acquired hypoglycemia syndromes, such as impaired awareness of hypoglycemia, through the putative effect of unsuspected recurrent episodes of nocturnal hypoglycemia. CONCLUSION: In efforts to decrease the risk of nocturnal hypoglycemic episodes, various strategies can be used to minimize the nocturnal hyperinsulinemia that is associated with many insulin replacement regimens. Regular blood glucose monitoring (particularly at bedtime), the ingestion of appropriate bedtime snacks, and the utilization of short- and long-acting insulin analogues may all help to prevent or minimize the frequency of nocturnal hypoglycemia.

Adult↗