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Query: UMLS:C0011849 (diabetes)
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Seven patients with necrotizing soft tissue infections of the perineum are described. Predisposing factors related to infection were present in four patients (diabetes mellitus, multiple myeloma, HIV, and a poorly defined immunodeficiency syndrome). Anaerobic and facultative anaerobic bacteria were cultured in each case. Two patients required skin graft closure of the debrided wounds, with the remaining wounds closed by contracture and epithelialization. A diverting sigmoid colostomy to facilitate wound care was performed on one patient who had complete dissolution of all anal sphincters. The role of hyperbaric oxygen therapy in four patients was of uncertain value.
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PMID:Synergistic soft tissue infections of the perineum. 161 51

Dupuytren's contracture is a deforming, fibrotic condition of the palmar fascia which has confounded clinicians and scientists since the early descriptions by Guillaume Dupuytren in 1831. It predominantly affects elderly, male caucasians, has a hereditary predisposition and has strong associations with diabetes, alcohol consumption, cigarette smoking and HIV infection. The major morphological features are an increase in fibroblasts, particularly around narrowed fibroblasts; a finding consistent with localised ischaemia. During ischaemia, adenosine triphosphate (ATP) is converted to hypoxanthine and xanthine, and endothelial xanthine dehydrogenase to xanthine oxidase (alcohol also mediates this change, a finding of particular relevance given the association of Dupuytren's contracture with alcohol intake). Xanthine oxidase catalyses the oxidation of hypoxanthine to xanthine and uric acid with the release of superoxide free radicals (O2-), hydrogen peroxide (H2O2) and hydroxyl radicals (OH.). These free radicals are highly reactive, with half-lives in the order of milliseconds and are toxic in high concentrations. A potential for free radical generation in Dupuytren's contracture was elicited by finding a sixfold increase in hypoxanthine concentrations in Dupuytren's contracture compared with control palmar fascia. In vitro studies affirmed the toxic effects of oxygen free radicals to Dupuytren's contracture fibroblasts, but also showed that, at lower concentrations (concentrations similar to those likely to occur in Dupuytren's contracture), free radicals had a stimulatory effect on fibroblast proliferation. Cultured fibroblasts were found to release their own O2-. These endogenously released free radicals were also found to be important in fibroblast proliferation. The collagen changes of Dupuytren's contracture were examined. The results established that fibroblast origin was unimportant, but that inhibition of type I collagen production at high fibroblast density accounted for the increase in type III/I collagen ratios observed by previous investigators. These biochemical and morphological observations throw new light on Dupuytren's contracture. They suggest that age, genetic and environmental factors may contribute to micro vessel narrowing with consequent localised ischaemia and free radical generation. Endothelial xanthine oxidase derived free radicals may both damage the surrounding stroma and stimulate fibroblasts to proliferate. Proliferating fibroblasts lay down and contract collagen in lines of stress.Progressive fibroblast proliferation and deposition of collagen is likely to encourage further microvessel narrowing with a positive feedback effect consistent with the progressive nature of the condition.
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PMID:An insight into Dupuytren's contracture. 161 55

Positron emission tomography (PET) allows, in combination with multiple radiopharmaceuticals, unique physiological and biochemical tissue characterization. Tracers of blood flow, metabolism and neuronal function have been employed with this technique for research application. More recently, PET has emerged in cardiology as a useful tool for the detection of coronary artery disease and the evaluation of tissue viability. Metabolic tracers such as fluorine-18 deoxyglucose (FDG) permit the specific delineation of ischaemically compromised myocardium. Clinical studies have indicated that the metabolic imaging is helpful in selecting patients for coronary artery bypass surgery or coronary angioplasty. More recent research work has concentrated on the use of carbon-11 acetate as a marker of myocardial oxygen consumption. Together with measurements of left ventricular performance, estimates of cardiac efficiency can be derived from dynamic 11C-acetate studies. The non-invasive evaluation of the autonomic nervous system of the heart was limited in the past. With the introduction of radiopharmaceuticals which specifically bind to neuronal structures, the regional integrity of the autonomic nervous system of the heart can be evaluated with PET. Numerous tracers for pre- and postsynaptic binding sites have been synthesized. 11C-hydroxyephedrine represents a new catecholamine analogue which is stored in cardiac presynaptic sympathetic nerve terminals. Initial clinical studies with it suggest a promising role for PET in the study of the sympathetic nervous system in various cardiac diseases such as cardiomyopathy, ischaemic heart disease and diabetes mellitus. The specificity of the radio-pharmaceuticals and the quantitative measurements of tissue tracer distribution provided by PET make this technology a very attractive research tool in the cardiovascular sciences with great promise in the area of cardiac metabolism and neurocardiology.
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PMID:Imaging of metabolism and autonomic innervation of the heart by positron emission tomography. 161 39

The interaction of endothelium-derived relaxing factor (EDRF) and oxygen-derived free radicals may potentially play an important role in the pathophysiology of complications associated with diabetes. In the present study, we investigated spontaneous EDRF release in diabetic rat aorta that is unmasked by the addition of superoxide dismutase (SOD). SOD produced a significantly greater relaxation in diabetic aorta compared with control aorta using both aortic ring and bioassay preparations. This relaxation was unaltered by pretreatment with catalase or indomethacin. Removal of the endothelium or pretreatment with either NG-monomethyl-L-arginine or methylene blue eliminated SOD-induced relaxation in both control and diabetic rings. Measurement of antioxidant enzymes revealed an elevation in catalase in diabetic aorta, with no difference in the SOD or glutathione peroxidase activity. The increase in catalase activity suggests increased exposure of diabetic aorta to hydrogen peroxide. Pretreatment of rings with the catalase inhibitor, 3-amino-1,2,4-triazole, attenuated the SOD-induced relaxation in diabetic aortic rings but had no effect in control aortic rings. In summary, our observations suggest that the diabetic rat aorta releases more spontaneous EDRF than control aorta; however, the activity of EDRF on vascular smooth muscle tone is masked by increased destruction by oxygen-derived free radicals.
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PMID:Regulation of spontaneous EDRF release in diabetic rat aorta by oxygen free radicals. 163 63

Survival is uncommon in bilateral cerebro-rhino-orbital mucormycosis treated surgically and medically. A 66-year-old man in previously good health had bilateral cerebro-rhino-orbital mucormycosis and newly diagnosed nonketotic diabetes mellitus at initial examination. Total loss of vision, proptosis, and ophthalmoplegia of both eyes were present. The patient was treated with aggressive surgical and medical therapies that included bilateral orbital exenteration, intravenous and local amphotericin B, hyperbaric oxygen, and control of the diabetes mellitus. One and one-half years after onset of the illness, the patient is alert and clinically stable. The importance of prompt diagnosis and aggressive treatment of this disease is emphasized by this case. Additionally, we suggest that adjunctive hyperbaric oxygen is a reasonable modality in the treatment of this often fatal disease.
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PMID:Adjunctive hyperbaric oxygen in the treatment of bilateral cerebro-rhino-orbital mucormycosis. 164 97

The following species; superoxide (O2-.), hydrogen peroxide (H2O2), hydroxyl radical (.OH) and singlet oxygen (1O2), are generally called as reactive oxygen species (ROS). These species have been suggested to play important roles in various diseases caused by oxygen toxicity such as ischemia, carcinogenesis, inflammation, diabetes and aging. During the past two decades, considerable interests have been focused on chemical and biological research of ROS. We have also reported about the research results on ROS, which can be classified as following below; 1) chemical reactivities of O2-., 2) formation and toxicity of 1O2, 3) chemical reactivities of .OH, 4) enzyme mechanism of xanthine oxidase, 5) development of the compounds which induce the formation of O2-. and H2O2 in living cells and 6) development of superoxide dismutase mimics. These studies are reviewed from the standpoint of both chemical and biological interests.
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PMID:[Chemical and biochemical studies on reactivities, formations and toxicities of reactive oxygen species]. 164 54

All the living molecules appear to suffer from the deleterious effects of aging, but the primary mechanisms of this inexorable evolution are still unknown. In the case of proteins, two major types of chemical reactions participate in the aging phenomena: 1) structural transformations induced by the addition of radicals by enzymic or non-enzymic reactions, 2) proteolytic cleavages. Among the reactions of the first group, the nonenzymatic glycation is the more generalized, not only in diabetic patients but also in non diabetic subjects. This glycation depends on the probabilities of encounters between circulating glucose molecules and free amino groups existing either at the N-terminal end of the polypeptide chains or on the lysyl side chains. These reactions are more frequent in the extracellular spaces and connective tissues because glucose circulates freely in these spaces, because the level of glucose is better controlled inside the cells (and even lower in diabetes mellitus), and finally because the proteins of these regions, such as the collagens, fibronectin and elastin, are relatively long lived, even if their life-span is really shorter than it was precedently believed. The binding of sugar residues to protein amino groups determines frequent modifications of structure that often make the molecule inactive. For instance, when a glucose unit binds to a lysyl radical located in the active center of an enzyme, it suppresses the activity of this enzyme. More generally, in the case of the connective tissue proteins that participate in complex supramolecular assemblies, the presence of additional radicals on some ponctual locations may interfere with the correct association of molecules. This is particularly true for basement membranes whose structure is impaired in diabetes. Glycation might also introduce abnormal cross-links between polypeptides or modify the antigenic power of some proteins and explain the formation of autoantibodies. Another property of glycated proteins is their reaction with oxygen leading to the formation of superoxide. The binding of a reducing sugar on an amino function is followed by an Amadori rearrangement that forms a ketol group. Ketols groups have the property to transmit electrons to molecular oxygen, and to forming superoxide radicals. Superoxide is capable of degrading only one protein: collagen, but it is also able to transform itself into hydrogen peroxide and hydroxyl radicals, which are far more toxic than O2-. The result of the formation of these oxygen free radicals from glycated proteins is the initiation of the degradation of several types of proteins, like the collagens.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Aging mechanisms of proteins]. 165 Dec 60

Elevated arterial pressure in patients with obesity-hypertension is associated with an increased cardiac output and total peripheral resistance. The elevated output is related to expanded intravascular volume that increases cardiopulmonary volume, venous return, and left ventricular preload; the elevated pressure and total peripheral resistance increase afterload. This dual ventricular overload promotes a dimorphic, concentric, and eccentric hypertrophy in response to the volume and pressure overload. Increased myocardial oxygen demand results from the elevated tension in the left ventricular wall, reflecting its increased diameter and pressure, and provides physiologic rationale for the greater potential of coronary arterial insufficiency and cardiac failure. There are greater renal blood flow and lower renal vascular resistance in patients with obesity-hypertension at any level of arterial pressure. This may be offset by an increased renal filtration fraction that may favor protein deposition and glomerulosclerosis, and predisposition of obese patients for diabetes may aggravate this problem. With weight reduction, these hemodynamic derangements may be reversed: intravascular volume contracts, cardiac output decreases, and arterial pressure falls.
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PMID:Obesity and hypertension. Hemodynamic aspects. 166 10

Nearly 50% of individuals with type II diabetes mellitus are over the age of 65 years. There are numerous reasons to maintain blood glucose levels below 11.1 nmol/L (200 mg/dl) in older persons, and there are a number of changes often seen with advancing age that persons, and there are a number of changes often seen with advancing age that may interfere with the management of diabetes mellitus, e.g. hypodipsia, anorexia, visual disturbance, altered renal and hepatic function, depression, impaired basoreceptor response and multiple medications. Hyperglycaemia appears to produce cognitive impairment which may lead to poor compliance. It is often difficult to manipulate diet in older people, and in fact dietary changes can lead to severe protein energy malnutrition. High maximum voluntary oxygen intake has been correlated with increased glucose disposal, but there is little evidence that physical exercise can improve diabetic control in the elderly. Oral sulphonylurea hypoglycaemic agents are extremely useful in the treatment of diabetes in these patients, but it should be remembered that they are more liable to develop hypoglycaemia than are younger diabetics. The role of metformin in the management of older diabetic patients is poorly studied. Many older persons can cope well with insulin therapy, but those with visual disturbances often make errors when drawing up insulin and require special attention. Combination therapy of insulin with oral hypoglycaemic agents is not recommended in this group of patients, and serum fructosamine is preferred to glycated haemoglobin to monitor control. Successful management of elderly diabetic patients thus requires an interdisciplinary team approach.
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PMID:The management of diabetes mellitus in older individuals. 171 59

Diabetic pregnancy is associated with an increased risk for fetal maldevelopment for a largely unknown reason. A decade ago, Norbert Freinkel suggested that the altered fuel mixture offered to the growing conceptus may be the key to most of the changes in the embryogenesis of diabetic pregnancy. He coined the term fuel-mediated teratogenesis. During early pregnancy, periods of maternal hyper- and hypoglycemia may cause marked changes in the availability of glucose to the conceptus. Also, increased concentrations of lipids, notably ketone bodies, and branched-chain amino acids in the maternal circulation contribute to a changed fuel mixture for the embryo. In a recent experimental study of diabetic rats, it was found that the maternal metabolism of all three major classes of nutrients and maternal somatic growth during gestation covaried with the development of the embryo. Consequently, the maintenance of normal concentrations of metabolites from all nutrient classes may be important for prevention of adverse fetal outcome in diabetic pregnancy. In vitro, a high glucose concentration causes embryonic dysmorphogenesis by generation of free oxygen radicals. An enhanced production of such radicals in embryonic tissues may be directly related to an increased risk of congenital malformations in diabetic pregnancy. Thus, the notion that alterations in the net transfer of cellular fuels from the diabetic mother to her offspring may cause embryonic dysmorphogenesis, which suggests that combustion of the fuel may produce compounds that impair embryonic development, has obtained experimental support. If this is also true for human diabetic pregnancy, it has therapeutic implications.
Diabetes 1991 Dec
PMID:Diabetic embryopathy. Studies with animal and in vitro models. 174 75


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