Glycemic index,glycemic load,and risk of type 2 diabetes

The possibility that high, long-term intake of carbohydrates that are rapidly absorbed as glucose may increase the risk of type 2 diabetes has been a long-standing controversy. Two main mechanisms have been hypothesized, one mediated by increases in insulin resistance and the other by pancreatic exhaustion as a result of the increased demand for insulin. During the past decade, several lines of evidence have collectively provided strong support for a relation between such diets and diabetes incidence. In animals and in short-term human studies, a high intake of carbohydrates with a high glycemic index (a relative measure of the incremental glucose response per gram of carbohydrate) produced greater insulin resistance than did the intake of low-glycemic-index carbohydrates. In large prospective epidemiologic studies, both the glycemic index and the glycemic load (the glycemic index multiplied by the amount of carbohydrate) of the overall diet have been associated with a greater risk of type 2 diabetes in both men and women. Conversely, a higher intake of cereal fiber has been consistently associated with lower diabetes risk. In diabetic patients, evidence from medium-term studies suggests that replacing high-glycemic-index carbohydrates with a low-glycemic-index forms will improve glycemic control and, among persons treated with insulin, will reduce hypoglycemic episodes. These dietary changes, which can be made by replacing products made with white flour and potatoes with whole-grain, minimally refined cereal products, have also been associated with a lower risk of cardiovascular disease and can be an appropriate component of recommendations for an overall healthy diet.     

Are C‐reactive protein and homocysteine cardiovascular risk factors in obese children and adolescents?

Background: Several prospective epidemiological studies have demonstrated that high-sensitivity C-reactive protein (hsCRP) and plasma homocysteine (hcy) are predictors of future coronary events among healthy men and women. The aim of the present study was therefore to investigate a possible relationship between hsCRP, hcy levels and body mass index (BMI), relative weight (RW), serum leptin levels, and cardiovascular risk factors in obese children and adolescents.
Methods: The study involved 28 obese children and adolescents (13 girls, 15 boys; BMI>95‰ for age and sex), 4.5–15 years of age (mean 10.7 ± 0.6 years), who attended hospital for a basic obesity check-up. The association between hsCRP, hcy levels and BMI, RW, serum leptin levels, and cardiovascular risk factors such as blood pressure (BP), lipid profile, serum fasting insulin levels, and insulin resistance indexes, was investigated.
Results: Serum hsCRP level was positively correlated with BMI ( r = 0.512, P  < 0.01), RW ( r = 0.438, P  < 0.05), systolic and diastolic BP ( r = 0.498, P  < 0.01), serum leptin levels ( r = 0.457, P  < 0.05), but not with serum lipid, glucose, fasting insulin, plasma hcy levels or insulin resistance indexes. For hcy level, in contrast, no correlation was found with BMI, RW, systolic and diastolic BP, serum lipid levels, leptin, hsCRP, glucose, fasting insulin levels, or insulin resistance indexes.
Conclusions: hsCRP is correlated with BMI, RW, BP and leptin, which are risk factors for coronary heart disease, which supports the relationship between obesity, inflammation and atherosclerosis. hsCRP in childhood obesity might be a useful index to predict possible atherosclerotic events.     

Hypoglycaemia causes degeneration of large myelinated nerve fibres in the vagus nerve of insulin-treated diabetic BB/Wor rats

The aim of this study was to find out whether dysglycaemia causes neuropathy in the vagus nerve of insulin-treated diabetic BB/Wor rats. Specimens were collected from the left vagus nerve proximal and distal to the level of recurrent laryngeal branch and from the recurrent branch itself in control rats and diabetic BB/Wor rats subjected to hyper- or hypoglycaemia. Myelinated and unmyelinated axons were counted and myelinated axon diameters were measured by electron microscopy. In controls, the vagus nerve proximal to the recurrent branch exhibited three regions in terms of fibre composition: part A was mainly composed of large myelinated axons, part B contained small myelinated and unmyelinated axons, and part C contained mainly unmyelinated axons. The distal level resembled part C at the proximal level and the recurrent branch resembled parts A and B. In hyperglycaemic rats, a normal picture was found at the proximal and distal levels of the vagus nerve and in the recurrent branch. In hypoglycaemic rats, signs of past and ongoing degeneration and regeneration of large myelinated axons were found at the proximal and distal levels and in the recurrent branch. We conclude that hypoglycaemia elicits degenerative alterations in large myelinated axons in the vagus and recurrent laryngeal nerves in diabetic BB/Wor rats. The absence of signs of neuropathy in unmyelinated and small myelinated axons suggests that the sensory and autonomic components of the nerve are less affected. In contrast, the hyperglycaemic rats examined here did not show obvious degenerative alterations.     

Yogurt and gut function

In recent years, numerous studies have been published on the health effects of yogurt and the bacterial cultures used in the production of yogurt. In the United States, these lactic acid-producing bacteria (LAB) include Lactobacillus and Streptococcus species. The benefits of yogurt and LAB on gastrointestinal health have been investigated in animal models and, occasionally, in human subjects. Some studies using yogurt, individual LAB species, or both showed promising health benefits for certain gastrointestinal conditions, including lactose intolerance, constipation, diarrheal diseases, colon cancer, inflammatory bowel disease, Helicobacter pylori infection, and allergies. Patients with any of these conditions could possibly benefit from the consumption of yogurt. The benefits of yogurt consumption to gastrointestinal function are most likely due to effects mediated through the gut microflora, bowel transit, and enhancement of gastrointestinal innate and adaptive immune responses. Although substantial evidence currently exists to support a beneficial effect of yogurt consumption on gastrointestinal health, there is inconsistency in reported results, which may be due to differences in the strains of LAB used, in routes of administration, or in investigational procedures or to the lack of objective definition of "gut health." Further well-designed, controlled human studies of adequate duration are needed to confirm or extend these findings.     

Adrenoceptor mechanisms underlying imipramine-induced memory deficits in rats

The post-training administration of tricyclic antidepressant imipramine impairs memory consolidation in the passive avoidance task. The present study investigated the effects of intrahippocampal (i.h.) injection of adrenoceptor agents on imipramine-induced (2-8 microg/rat) amnesia. The administration of the alpha1-adrenoceptor agonist phenylephrine (0.05 microg/rat) and the alpha1-adrenceptor antagonist prazosin (0.5 microg/rat) did not alter the effect of imipramine. The lower doses of phenylephrine (0.005 and 0.015 microg/rat) impaired, while the higher dose of the drug (0.025 and 0.05 microg/rat) improved retention. The effect of phenylephrine was not altered by prazosin (0.5 and 1 microg/rat) pretreatment, although prazosin alone decreased retention latencies. The alpha2-adrenoceptor antagonist yohimbine (0.5 and 1 microg/rat) decreased the response induced by imipramine. However, the alpha2-adrenoceptor agonist clonidine (0.08 microg/rat) did not alter the effect of the drug. Clonidine (0.15 and 0.3 microg/rat) by itself decreased, while yohimbine (1 and 2 microg/rat) increased retention latencies. Yohimbine pretreatment attenuated the effect of clonidine. It is concluded that alpha2-adrenoceptor mechanism(s) may be involved in imipramine-induced impairment of memory.     

Risk factors of thyroid abnormalities in bipolar patients receiving lithium: a case control study

Background

Lithium-induced thyroid abnormalities have been documented in many studies. They may occur despite normal plasma lithium levels. The objectives of this study were: 1) to determine possible relationship between lithium ratio, defined as erythrocyte lithium concentrations divided by plasma lithium concentrations, and thyroid abnormalities in bipolar patients receiving lithium and 2) to find other possible risk factors for developing thyroid abnormalities in the subjects.

Methods

Sixty-eight bipolar patients receiving lithium therapy were enrolled in a cross-sectional evaluation of thyroid function test and thyroid size. Patients were divided into two groups based on their thyroid function tests and thyroid sizes. Erythrocyte and plasma lithium concentrations were determined by atomic absorption spectrometry for each patient. Lithium ratio was then calculated.

Results

No significant differences were found between age, positive family history of affective disorder, plasma lithium concentration, erythrocyte lithium concentration, and lithium ratio comparing the two groups. Thyroid abnormalities was significantly higher in women than in men (p < 0.05).

Conclusions

Lithium ratio does not appear to have a predictive role for thyroidal side effects of lithium therapy. Female gender was the main risk factor. We suggest more frequent thyroid evaluation of bipolar women who are treated with lithium.