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Query: UMLS:C0011881 (diabetic nephropathy)
 10,836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glomerular filtration rate has been found to be elevated in the early stage of insulin-dependent diabetes mellitus and has been proposed to play a pathogenetic role in the development of diabetic nephropathy. However, the reports about the change in renal plasma flow (RPF) among diabetic subjects were inconsistent, suggesting that the presence of hyperglycemia may in some way interfere the procedures of RPF measurement. Recently, it has been reported that the glucose in the urine may react with p-aminohippurate (PAH), a widely used marker for RPF measurement, and influence the chemical measurement of PAH, misleading the result of RPF value. In fact, we obtained the decrease of PAH value in urine samples obtained from diabetic subjects during the storage for one week in frozen condition. In order to clarify the factors which may influence the glucose-PAH reaction, we have conducted various in vitro studies. The decrease of PAH values was dose-dependent to urine glucose. The pH of the test solution or urine was also found to greatly influence the result of PAH measurement when glucose was present. The analysis of glucose-PAH reactants by HPLC suggested that the amino residue of PAH might be reacted with glucose, producing the glycation product (Schiff base). The rate of glycation of PAH was time- and pH-dependent. However, when the reaction time was prolonged at the last step of PAH measurement after the addition of the acid solution, the decrease of PAH value was gradually corrected reaching to the theoretical value in 7 hours.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A study of the measurement of p-aminohippurate in diabetic subjects]. 148 8

Ultrastructural, immunohistochemical and biochemical studies have improved our knowledge on the events occurring during the development of diabetic late complications. Immunohistochemical investigations of diabetic kidneys, using antibodies against various components of the extracellular matrix, showed increased collagen type IV (alpha 1,alpha 2-chain) deposition in the mesangial matrix, and a decrease of heparan sulphate proteoglycan in the mesangial matrix and glomerular basement membrane. Changes in matrix components seem to be the underlying cause of the alterations in renal function, as reflected by albuminuria and proteinuria. The occurrence of collagen type III in late diffuse glomerulosclerosis has been interpreted as an irreversible change in glomerular structure. The extent of alteration of the extracellular matrix correlates to a certain extent with the severity of nephropathy of the individual subject. The studies performed to date support the hypothesis that hyperglycaemia, whatever its origin, is the primary cause of diabetic late complications, although the pathobiochemical mechanisms are not yet fully understood. Increased intra- and extracellular levels of glucose and its derivatives are thought to contribute to diabetic tissue dysfunction. Three pathobiochemical theories are favoured in the current discussion: i) the polyol pathway ii) non-enzymatic glycation of proteins iii) direct influence of hyperglycaemia on the synthesis of matrix components. The evidence for the participation of the polyol pathway in the pathogenesis of diabetic nephropathy comes mainly from animal data using aldose reductase inhibitors, but only limited data are available for humans, so that the significance of this pathomechanism cannot yet be determined.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glomerular changes in diabetes mellitus. 149 55

Diabetic nephropathy not only involves vascular and glomerular changes but also affects tubular metabolism, structure and function. Under acute insulin withdrawal the tubular size increases with glomerular hyperfiltration. Insulin like growth factor 1 (IGF1) has been found to be a candidate mediator involved under these conditions. Tubular carbohydrate metabolism is characterized by gluconeogenesis in the proximal tubule, glycolytic enzymes in the distal segments and high aldose reductase activity in the structures of the renal papilla. In the diabetic state, gluconeogenesis is stimulated by changes of the acid base status. Mitochondrial glucose oxidation is decreased by inhibition of pyruvate dehydrogenase activity through preferential oxidation of fatty acids and ketone bodies. The increase in glycogen in distal tubule cells and sorbitol accumulated in papillary structures can be explained by the high extracellular glucose supply under diabetic conditions. Fatty acids taken up in excess of tubular energy needs accumulate in the nephron as triacylglycerols, mainly in the proximal convoluted tubule. Fatty acid oxidation is inhibited by ketone bodies in proximal and outer medullary tubules, leading to preferential oxidation of the latter under ketotic conditions. Ammonia formed during tubular metabolism of glutamine increases in metabolic acidosis but is suppressed by ketone bodies, leading to a nitrogen sparing effect of ketone bodies. All acute metabolic derangements are abolished, and normal metabolism reestablished by adequate insulin treatment in vivo.
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PMID:Carbohydrate and lipid metabolism of the renal tubule in diabetes mellitus. 149 59

The number of elderly patients with insulin-dependent diabetes mellitus (IDDM) is increasing because of the prolongation of life due to the improvement of diabetic control. For better management of elderly patients with IDDM, we investigated the clinical and genetic characteristic of older patients with IDDM in comparison with younger patients. The subjects studied consisted of 19 patients with IDDM treated at the Department of Geriatric Medicine, Osaka University Hospital. Among the 19 subjects, 7 patients (37%) were more than 50 years old, including 3 patients (16%) more than 65 years old. The clinical and genetic characteristics of these 7 patients (older patients group) were compared with those of 12 patients (younger patient group) whose age was less than 50 years old. The age at onset of IDDM was significantly higher in older patient group (46 +/- 13 years old; mean +/- SD) than in younger patient group (34 +/- 6 years old). There was no significant difference in the duration of IDDM between older and younger patients (13 +/- 6 and 12 +/- 8 years, respectively). There were no significant differences in daily insulin dose, glycemic control (fasting plasma glucose and HbA1c levels) and glycemic stability as measured by the standard deviation of 10 measured fasting plasma glucose levels between the two groups. The frequency of diabetic retinopathy and neuropathy in the older patients was slightly, but not significantly, higher than that in younger patients. The frequency of diabetic nephropathy was similar in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Clinical characteristic of elderly patients with insulin-dependent diabetes mellitus]. 149 46

The enzyme glucosaminyl N-deacetylase plays a key role in heparan sulphate biosynthesis since N-deacetylation is a prerequisite for N- and further O-sulphation of the carbohydrate polymer. Diabetes induced inhibition of this enzyme could be an important factor in the development of diabetic nephropathy. In this study glomerular glucosaminyl N-deacetylase activity and urinary albumin excretion were measured in insulin-treated streptozotocin-diabetic rats. Furthermore, in an attempt to provide evidence of genetically dependent differences in the vulnerability of the N-deacetylase enzyme, two closely related rat strains (H and U) were studied. A significant 10% inhibition in enzyme activity was found among rats with mean blood glucose values between 9 and 17 mmol/liter, P less than 0.05. There was a pronounced difference between the two rat strains in the vulnerability of the enzyme against blood glucose alterations. The U rat appeared highly sensitive to short-term blood glucose control judged by the correlation between blood glucose and N-deacetylase activity (r = -0.73, P = 0.005, N = 16), where no such correlation was found in the H rat (r = 0.02, P = 0.9, N = 14). Urinary albumin excretion was increased in diabetic H rats and significantly correlated to glomerular N-deacetylase activity (r = -0.62, P = 0.02, N = 14). The U rats developed a 10-fold rise in albumin excretion compared to H rats, but this albuminuria was apparently not related to the presence of diabetes or correlated to glomerular N-deacetylase activity. It is concluded that the diabetes induced inhibition of glucosaminyl N-deacetylase may play an important role in the pathogenesis of diabetic nephropathy.
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PMID:Inhibition of glomerular glucosaminyl N-deacetylase in diabetic rats. 151 99

Experimental animal studies have demonstrated a renal protective effect of ACE inhibition therapy in diabetes mellitus and the remnant kidney model of chronic renal failure. The mechanism of this effect is secondary, at least in part, to the drugs' effects on glomerular hemodynamics. In addition, there is further evidence to suggest that ACE inhibitors may influence other pathogenic mechanisms of progressive renal insufficiency. Preliminary data in clinical studies suggest that ACE inhibition therapy decreases proteinuria and may ameliorate the decline of the glomerular filtration rate in diabetic nephropathy and progressive renal insufficiency of other etiologies. However, before this conclusion can be definite, a large, prospective, randomized clinical trial is required to compare ACE inhibitors to conventional antihypertensive agents. Since calcium channel blockers are metabolically neutral in that they do not increase serum cholesterol or glucose levels and generally do not cause orthostatic hypotension, they may be ideal agents for such a comparison study.
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PMID:Progressive renal insufficiency: the role of angiotensin converting enzyme inhibitors. 155 7

Glomerular hyperfiltration, a risk factor for diabetic nephropathy, has been reported in type I insulin-dependent diabetics, but it is not clear if it occurs in other types of diabetes. To ascertain the prevalence of glomerular hyperfiltration in various types of diabetes, we measured glomerular filtration rate (GFR) in 158 diabetics (91 type I, 36 type II without insulin treatment, 20 type II with insulin treatment, and 11 subjects with diabetes secondary to chronic pancreatitis), and classified them as hyper-, normo-, or hypofiltration according to values measured in 36 age-match controls. After elimination of subjects with overt renal disease or hypertension, glomerular hyperfiltration was detected in 35% of the type I diabetics, 32% of the type II diabetics without insulin treatment, one subject with chronic pancreatitis, and one type II diabetics with insulin treatment. Glomerular hyperfiltration was associated with high blood glucose in type I, insulin-dependent diabetics, and with a high apolipoprotein B/A1 ratio in type II, non-insulin-dependent diabetics without insulin treatment. In all subjects with glomerular hyperfiltration, GFR values and urinary albumin excretion were positively related (r = 0.33; n = 34; p = 0.05). Glomerular hyperfiltration is detectable among all types of diabetics.
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PMID:Glomerular hyperfiltration in type I, type II, and secondary diabetes. 156 54

A large number of experimental studies in animals and retrospective or non-randomised prospective studies in humans provide support for the concept that the microvascular complications of diabetes mellitus are dependent on hyperglycaemia. This review focuses on four potential biochemical pathways linking hyperglycaemia to changes within the kidney which can plausibly be linked to the functional and structural changes characterising diabetic nephropathy. These four pathways are the polyol pathway, non-enzymatic glycation, glucose autoxidation and de novo synthesis of diacylglycerol leading to protein kinase C and phospholipase A2 activation. Rather than being independent, there are several potential interactions between these four pathways which may explain confusing and overlapping effects observed in studies examining inhibitors of individual pathways. As many of the steps which follow on glucose metabolism are subject to modification by dietary and pharmacological means, the further delineation of the pathogenetic sequence leading to tissue damage in diabetes should allow a logical and effective approach to the prevention or treatment of the complications of diabetes.
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PMID:The link between hyperglycaemia and diabetic nephropathy. 161 21

Diabetes mellitus is associated with significant morbidity and mortality caused by the micro- and macro-vascular complications that all too frequently develop during the lifetime of the diabetic patient. In attempts to treat the complications of diabetes, several different treatment strategies have been investigated. The role of tight blood glucose control in the treatment of diabetic vascular complications has recently been challenged, as the existing data in support of this mode of therapy are currently inconclusive. Perhaps more effective in preventing many of the vascular complications is the rigorous treatment of hypertension that frequently accompanies diabetes mellitus. Epidemiological studies have demonstrated that the presence of hypertension significantly contributes to the development and progression of diabetic nephropathy, retinopathy, cardiovascular disease, and possibly neuropathy. Preliminary clinical studies demonstrate that the progression of diabetic renal disease can be slowed by vigorous antihypertensive therapy. Among the various antihypertensive agents used to treat the hypertension associated with diabetes mellitus, calcium channel blockers are emerging as one of the agents of first choice. This is because of their very low side effect profile and their absence of detrimental effects on serum lipid levels and glucose tolerance. Calcium channel blockers may be of additional potential benefit to the diabetic patient by slowing the progression of atherosclerosis, reversing the intracellular calcium defects that may contribute to the pathogenesis of diabetic cardiomyopathy, and protecting against the progression of chronic renal disease.
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PMID:The future of calcium channel blocker therapy in diabetes mellitus. 172 50

Late complications of diabetes mellitus include a variety of clinical pictures, mainly related to the involvement of the arterial wall both of large vessels (macroangiopathy) and small vessels (microangiopathy), and of the peripheral nervous system (neuropathy). Their presence in almost all types of diabetes indicates that there is a common pathogenetic mechanism, which can be substantially identified in high blood glucose levels and related alterations. Hyperglycemia, in fact, leads to some metabolic abnormalities, i.e. non-enzymatic glycosylation of proteins and polyol pathway activity; moreover it can negatively affect the pattern of some hormones, especially GH and sex steroids, and normal rheological and clotting properties of blood. These abnormalities, confirmed by experimental models, play a key role in the development of late diabetic complications. However some evidence indicates that a genetic background may predispose to their development or protect from their onset. The two main forms of diabetic retinopathy, non-proliferative and proliferative, show an incidence which increases with age and duration of diabetes, reaching 100% when diabetes lasts for more than 20 years. The risk of blindness, which is very high for the proliferative form, has been dramatically reduced by laser-photocoagulation. Diabetic nephropathy affects a lesser number of diabetics but, after a silent or preclinical stage, leads to renal failure and subsequent replacement therapy. Strict metabolic control in the silent stage and later rigid anti-hypertensive treatment can prevent or retard the evolution of this complication. A close association has been observed between diabetes and hypertension, which can directly affect the onset and evolution of diabetic nephropathy, probably through a common genetic mechanism. Diabetic neuropathy has a wide variety of clinical manifestations, at somatic, autonomic and central levels and can greatly modify the quality and expectancy of life. However, the major cause of death in diabetic subjects is large vessel disease or macroangiopathy, which is similar to non-diabetic atherosclerosis regarding the main histopathological and clinical manifestations but has a much higher prevalence and severity. Finally, a specific cardiomyopathy has also been described in diabetes mellitus and can account for the high rate of heart failure observed in these patients.
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PMID:The late complications of diabetes mellitus. 174 48


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