Suggest Category | Add URL

Website details:

Diabetes News and Articles      
Diabetes Mellitus: Overview, Causes, Symptoms, Risk factors, Treatment
http://www.health.am/db/

[ Date added: 2007-11-11 ]


Feed : http://www.health.am/db/rss_2.0/
Diabetes Mellitus: Overview, Causes, Risk Factors, Treatment

Controlling Insulin Is Good for Diabetes—and Breast Cancer?
Doctors have long encouraged patients with diabetes to exercise regularly to help control their insulin levels and to maintain a healthy weight. Now, breast oncologists at Dana-Farber Cancer Institute in Boston are studying the relationship between exercise, weight, and insulin levels and the risk of breast cancer recurrence. ?We know that women who are overweight at the time of breast cancer diagnosis have a higher risk of recurrence than lean women, but the reasons for this are not clear,? says Jennifer Ligibel, MD. ?Recent evidence suggests that high insulin levels, which are common in overweight women, may be involved in the increased risk of breast cancer recurrence.? Based on these findings, Ligibel and her colleagues are conducting several studies to examine the potential benefits of regular exercise, diet modification and other weight-control activities in breast cancer survivors. The Active After Cancer Trial explores whether a telephone-based program can motivate patients to start an exercise program after completing treatment for early stage breast cancer.
Mayo Clinic discovery may help diabetic gastric problem
Mayo Clinic researchers have found what may provide a solution to one of the more troubling complications of diabetes?delayed gastric emptying or gastroparesis. The researchers showed in animal models that a red blood cell derivative increases production of a key molecule, normalizing the digestive process. The findings appear in the current online issue of the journal Gastroenterology. Gastroparesis occurs when the stomach retains food for longer periods. When that food eventually passes into the small intestine, insulin is released. Because the passage of food out of the stomach becomes unpredictable, maintaining a proper blood glucose level?critical for controlling diabetes?also becomes difficult. Gastroparesis can cause pain, nausea, vomiting, stomach spasms and weight loss due to inadequate absorption of nutrients. The abnormally high blood glucose levels cause chemical changes in nerves and in pacemaker cells which regulate digestive processes in the gut, and damage blood vessels that carry oxygen and nutrients to cells. ?If these data are confirmed in humans, it may point toward a treatment for this difficult problem,? says Gianrico Farrugia, M.D., Mayo Clinic gastroenterologist and senior author on the study. ?Our goal is to normalize gastric emptying and therefore improve a patient?s quality of life and glucose control.?
Anxious folks may spot diabetes symptoms early
Being anxious may be good for your health, at least if you have risk factors for type 2 diabetes, new research shows. Among 204 patients newly diagnosed with the disease, those with more anxious temperaments were diagnosed at an earlier stage compared with their more relaxed peers. The relationship was particularly strong among younger people, who do not normally undergo routine screening for diabetes. The patients who were diagnosed early were also more likely to have better control of the diabetes, regardless of their age.
Pathophysiology of Hyperglycemia
An enormous amount of research has been dedicated to unraveling the pathophysiology of type 2 diabetes mellitus over the last 30 years. While a large number of reviews have been devoted to its description, this section follows the line of our recent seminar. Insulin is the key hormone for regulating blood glucose. In general, normoglycemia is maintained by the balanced interplay between insulin secretion and the efficacy of insulin actions. In the fasting state, the major part of glucose is produced by the liver, and roughly half of it is used for brain glucose metabolism.  The remainder is taken up by various tissues, mainly muscle and for a minor part adipose tissue. In this situation insulin levels are low, and have no appreciable effect on muscle glucose uptake. 
Heredity in Type 2 Diabetes Mellitus
The fact that more than half of obese insulin-resistant subjects will never develop diabetes points to susceptibility for the disease in some humans, while protective factors against the disease are present in others. Indeed, a positive family history confers a two- to threefold increased risk for the disease with a 15% to 30% risk to develop type 2 diabetes or IGT in first- degree relatives of type 2 diabetes subjects. The risk is even higher (around 60% by the age of 60 years) if both parents have diabetes. Similarly, if one twin has type 2 diabetes, the risk for type 2 diabetes mellitus in the other twin is higher in monozygotic (identical) twins (35% to 58%) as compared with dizygotic twins (around 20%). A caveat is the presence of low birth weight in many twins, since low birth weight per se associates with increased risk of type 2 diabetes later in life. Genetic Factors The polygenic nature of the disease has it made difficult to dissect individual genes conferring increased risk for diabetes. In general, two methods, the so-called candidate gene approach and the genome-wide scan approach have been used. 
Genome-Wide Scans
A large number of genome-wide scans has been performed. Since initial positive findings have been replicated for over 20 genomic regions, the search for the genes responsible for the association with diabetes has proven to be difficult. However, three genes have now been found in this manner, calpain-10, ENPP1, and TCF7L2. Calpain-10 The calpain-10 gene encodes for a cysteine protease reported to be responsible for the association of a region in chromosome 2 with diabetes. A recent meta-analysis indicates that several single-nucleotide polymorphisms (SNPs) are responsible for the association, each with only a modest effect with relative risks between 1.10 and 1.5. Genetic variation in calpain-10 may affect sensitivity (83) or insulin secretion. It has also been shown to inhibit a protease involved in mitochondrial function, which might relate to mitochondrial dysfunction as is often observed in type 2 diabetes. ENPP1 Genome-wide scans often lead to regions that are so wide that research is often directed also by candidate genes in that specific region. The 6q16-q24 region harbors the ectonucleotide pyrophosphate/phosphodiesterase 1 (ENPP1 or PC-1) gene, which is a candidate for insulin resistance since the gene product can interact with the insulin - insulin receptor complex, thereby diminishing receptor activation. One haplotype conferred a relative risk of roughly 1.50 for type 2 diabetes and for obesity. The highly prevalent K121Q polymorphism has been found in vitro to worsening inhibition of insulin - insulin receptor autophosphorylation by the ENPP protein. 
Beta-Cell Dysfunction
Although abnormalities of insulin secretion in the pathophysiology of diabetes have often been neglected, they occur already early during the disease and can often already be demonstrated in subjects with normal glucose tolerance (first-degree relatives of type 2 diabetes). Normal Insulin Secretion After uptake of glucose pancreatic beta-cell glucose is rapidly degraded in oxidative glucose metabolism, leading to ATP formation. ATP is involved in beta-cell membrane depolarization. The ADP/ATP ratio, the sulfonylurea receptor-1 (SUR 1) protein, which closes the adjacent potassium channel (potassium inward rectifier 6.2, KIR 6.2 channel).  The closure of the potassium channels will decrease the membrane potential, which leads to opening of voltage-gated calcium channels; this induces the release of insulin-containing granules (Fig. 5). Upon stimulation with glucose, insulin is released with a short-lasting peak of a few minutes (so-called ?first-phase") followed by a slowly evolving second phase; the second phase lasts as long as the plasma glucose level is elevated.
Insulin Effects in the Central Nervous System
Insulin receptors are also expressed throughout the brain with particularly high concentrations in the hypothalamus, the hippocampus, and the cortex. In humans, however, positron emission tomography (PET) studies repeatedly failed to reveal effects of hyperinsulinemia on brain glucose uptake.  Since glucose transport is probably not an important downstream effector of insulin in neurons because this is largely facilitated by GLUT3 and, to a minor extent, GLUT1 (an insulin-independent glucose transporter) the human brain has been traditionally regarded as an insulin-insensitive organ. Nevertheless, an insulin effect on neuronal glucose oxidation or glial glycogen metabolism can not be excluded. The most relevant neuronal insulin effect at the cellular level seems to be the inhibition of norepinephrine reuptake.
Insulin Resistance
Insulin resistance is present when the biological effects of insulin are subnormal for both glucose disposal in skeletal muscle and suppression of endogenous glucose production primarily in liver. In the fasting state, however, muscle accounts for only a small proportion of glucose disposal (less than 20%) while endogenous glucose production is responsible for all of the glucose appearing in plasma. In patients with type 2 diabetes and in patients with impaired fasting glucose (IFG) endogenous glucose production is accelerated.
Modified Insulin Most Effective for Controlling Post-meal Blood Sugar Levels
Pre-mixed insulin analogues, a modified form of conventional pre-mixed human insulin, are more effective than long-acting analogues for controlling high blood sugar levels after meals in patients with type 2 diabetes, according to a report funded by the Agency for Healthcare Research and Quality, part of the U.S. Department of Health and Human Services. Conventional pre-mixed human insulin, however, appears to be equally effective as pre-mixed insulin analogues for lowering blood sugar levels when patients go eight or more hours without eating, according to the report. A version of the analysis is available on-line in the Annals of Internal Medicine. Type 2 diabetes accounts for more than 90 percent of diabetes. The number of Americans diagnosed with type 2 diabetes tripled from 5.6 million in 1980 to 15.8 million in 2005. Obesity increases the risks of developing type 2 diabetes. Diabetes can cause serious problems with the heart, kidneys, eyes and nerves. Many patients with type 2 diabetes control their blood sugar through diet and use of oral medications. Recent research suggests that good blood glucose control can reduce loss of sight, kidney failure, and heart disease.

Newsfeed display by CaRP