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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autoantibody and T cells reacting with islet proteins have been demonstrated in patients with type 1 diabetes. In recent years an increasing number of children have been clinically classified with type 2 (not ketosis prone, evidence of insulin resistance, presence of acanthosis nigricans, and obesity) or indeterminant diabetes (admixture of clinical features of types 1 and 2). In this study, we compared the islet cell autoantibody and T-cell responses to islet proteins in type 2 (n = 19) and indeterminant (n = 16) children (<18 yr of age) to classic type 1 (n = 37) diabetic patients. We observed that 37 of 37 type 1 diabetic children demonstrated autoantibody and/or T-cell reactivity to islet proteins. Fourteen of the 19 type 2 patients were positive for islet cell autoantibodies, and six of 14 were positive for T-cell responses to islet proteins. For the indeterminant patients, 11 of 16 of the patients were positive for autoantibodies, and six of 16 patients were positive for T-cell responses to islet proteins. These results demonstrate that autoimmunity to islet proteins is present in a high percentage of children classified as indeterminant or type 2 diabetes. Moreover, the presence of obesity or acanthosis nigracans does not reliably distinguish children with or without islet cell autoimmunity.
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PMID:Autoimmunity to islet proteins in children diagnosed with new-onset diabetes. 1512 45

Ketosis-prone diabetes (KPD) is a rare form of type 2 diabetes, mostly observed in subjects of west African origin (west Africans and African-Americans), characterized by fulminant and phasic insulin dependence, but lacking markers of autoimmunity observed in type 1 diabetes. PAX4 is a transcription factor essential for the development of insulin-producing pancreatic beta-cells. Recently, a missense mutation (Arg121Trp) of PAX4 has been implicated in early and insulin deficient type 2 diabetes in Japanese subjects. The phenotype similarities between KPD and Japanese carriers of Arg121Trp have prompted us to investigate the role of PAX4 in KPD. We have screened 101 KPD subjects and we have found a new variant in the PAX4 gene (Arg133Trp), specific to the population of west African ancestry, and which predisposes to KPD under a recessive model. Homozygous Arg133Trp PAX4 carriers were found in 4% of subjects with KPD but not in 355 controls or 147 subjects with common type 2 or type 1 diabetes. In vitro, the Arg133Trp variant showed a decreased transcriptional repression of target gene promoters in an alpha-TC1.6 cell line. In addition, one KPD patient was heterozygous for a rare PAX4 variant (Arg37Trp) that was not found in controls and that showed a more severe biochemical phenotype than Arg133Trp. Clinical investigation of the homozygous Arg133Trp carriers and of the Arg37Trp carrier demonstrated a more severe alteration in insulin secretory reserve, during a glucagon-stimulation test, compared to other KPD subjects. Together these data provide the first evidence that ethnic-specific gene variants may contribute to the predisposition to this particular form of diabetes and suggest that KPD, like maturity onset diabetes of the young, is a rare, phenotypically defined but genetically heterogeneous form of type 2 diabetes.
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PMID:PAX4 gene variations predispose to ketosis-prone diabetes. 1550 90

This article proposes five stages in the progression of diabetes, each of which is characterized by different changes in beta-cell mass, phenotype, and function. Stage 1 is compensation: insulin secretion increases to maintain normoglycemia in the face of insulin resistance and/or decreasing beta-cell mass. This stage is characterized by maintenance of differentiated function with intact acute glucose-stimulated insulin secretion (GSIS). Stage 2 occurs when glucose levels start to rise, reaching approximately 5.0-6.5 mmol/l; this is a stable state of beta-cell adaptation with loss of beta-cell mass and disruption of function as evidenced by diminished GSIS and beta-cell dedifferentiation. Stage 3 is a transient unstable period of early decompensation in which glucose levels rise relatively rapidly to the frank diabetes of stage 4, which is characterized as stable decompensation with more severe beta-cell dedifferentiation. Finally, stage 5 is characterized by severe decompensation representing a profound reduction in beta-cell mass with progression to ketosis. Movement across stages 1-4 can be in either direction. For example, individuals with treated type 2 diabetes can move from stage 4 to stage 1 or stage 2. For type 1 diabetes, as remission develops, progression from stage 4 to stage 2 is typically found. Delineation of these stages provides insight into the pathophysiology of both progression and remission of diabetes.
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PMID:Five stages of evolving beta-cell dysfunction during progression to diabetes. 1556 5

Hyperosmolar hyperglycemic state is a life-threatening emergency manifested by marked elevation of blood glucose, hyperosmolarity, and little or no ketosis. With the dramatic increase in the prevalence of type 2 diabetes and the aging population, this condition may be encountered more frequently by family physicians in the future. Although the precipitating causes are numerous, underlying infections are the most common. Other causes include certain medications, non-compliance, undiagnosed diabetes, substance abuse, and coexisting disease. Physical findings of hyperosmolar hyperglycemic state include those associated with profound dehydration and various neurologic symptoms such as coma. The first step of treatment involves careful monitoring of the patient and laboratory values. Vigorous correction of dehydration with the use of normal saline is critical, requiring an average of 9 L in 48 hours. After urine output has been established, potassium replacement should begin. Once fluid replacement has been initiated, insulin should be given as an initial bolus of 0.15 U per kg intravenously, followed by a drip of 0.1 U per kg per hour until the blood glucose level falls to between 250 and 300 mg per dL. Identification and treatment of the underlying and precipitating causes are necessary. It is important to monitor the patient for complications such as vascular occlusions (e.g., mesenteric artery occlusion, myocardial infarction, low-flow syndrome, and disseminated intravascular coagulopathy) and rhabdomyolysis. Finally, physicians should focus on preventing future episodes using patient education and instruction in self-monitoring.
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PMID:Hyperosmolar hyperglycemic state. 1588 46

The study analyzed the clinical background and eating habits of Japanese youth-onset type 2 diabetes. Thirty-six patients with type 2 diabetes (22 males, 14 females) with onset in less than 20-year-old were studied. All patients were negative for anti-glutamic acid decarboxylase (GAD) antibody and islet cell antibody. Cases diagnosed as having abnormalities in the mitochondrial gene, maturity onset diabetes of the young (MODY), and apparent type 1 diabetes were excluded from the study. Urinary ketone was detected positive in 11 cases among 36 patients at the onset of diabetes. We compared the clinical characteristics and food compositions between the patients with ketonuria and those without ketonuria. Age and urinary C-peptide secretion did not show any significant difference between both groups. In the patients with ketonuria, male to female ratio was remarkably high (10:1) compared with the group without ketonuria (12:13). Positive diabetic family history was predominantly higher in the group with ketonuria (11/11) than that in the group without ketonuria (17/25). All these were identical to previously reported characteristics of soft-drink ketosis. However, we in this study, revealed the difference of total calorie intake and dietary composition between youth-onset type 2 diabetes with and without ketonuria. As a result dietary contents such as carbohydrate, fat and confectionery in the former group were also 1.5, 1.4-2.4 times higher, respectively, than those in the latter group.
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PMID:Clinical characteristics of Japanese youth-onset type 2 diabetes with ketonuria. 1594 60

Fatty acids are the major source of energy for most tissues during periods of negative energy balance; however, fatty acids can, in some circumstances, have pathological effects. Fatty acids are stored as triacylglycerols (TAG), mostly in the various adipose tissue depots of the body. However, if blood unesterified fatty acid (NEFA) levels are elevated for prolonged periods, as may occur during lactation or obesity, TAG can accumulate in other tissues including liver and muscle cells (myocytes), and this can have pathological consequences such as the development of ketosis (Grummer, 1993; Drackley et al. 2001) or type 2 diabetes (Boden & Shulman, 2002; McGarry, 2002).
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PMID:Lipid metabolism during lactation: a review of adipose tissue-liver interactions and the development of fatty liver. 1622 62

This chapter describes a physiological and profound effect of amylin to inhibit meal-related glucagon secretion. Glucagon is processed from a large precursor, proglucagon, in a tissue-specific manner in pancreatic alpha-cells. In addition to amino acid nutrient stimuli, glucagon is also secreted in response to stressful stimuli, such as hypoglycemia and hypovolemia. Glucagon primarily acts on liver to initiate glycogenolysis and gluconeogenesis, resulting in a rapid increase in endogenous production of glucose. With longer stimulation, glucagon action at the liver results in a glucose-sparing activation of free fatty acid oxidation and production of ketones. During hypoglycemia, glucagon secretion is clearly a protective feed-back, defending the organism against damaging effects of low glucose in brain and nerves (neuroglycopenia). Amino acid-stimulated glucagon secretion during meals has a different purpose: amino acids stimulate insulin secretion, which mobilizes amino acid transporters and effects their storage in peripheral tissues. At the same time, insulin obligatorily recruits GLUT4 glucose transporters in muscle and fat. The hypoglycemic potential of such GLUT4 mobilization is averted only by the simultaneous liberation of endogenous glucose in response to feedforward (anticipatory) glucagon secretion. The effect of amylin and its agonists to inhibit amino acid-stimulated glucagon secretion is both potent (EC50 = 18 pM) and profound (approximately 70% inhibition). This glucagonostatic action appears to be extrinsic to the pancreatic islet, occurring in intact animals and in patients, but not in isolated islets or isolated perfused pancreas preparations. On the other hand, the effect of hypoglycemia to stimulate glucagon secretion, which is intrinsic to the islet and occurs in isolated preparations, is not affected by amylin or its agonists. The physiological interpretation of these actions fits with the general concept, illustrated in Fig. 1, that amylin and insulin secreted in response to meals shut down endogenous production as a source of glucose, in favor of that derived from the meal. Amylin and insulin secreted in response to nutrients already absorbed act as a feedback switch for glucose sourcing. The insulinotropic (incretin) gut peptides, GLP-1 and GIP, secreted in response to yet-to-be-absorbed intraluminal nutrients, amplify beta-cell secretion and thereby activate the glucose sourcing switch in a feedforward manner. Hypoglycemia-stimulated glucagon secretion and nutrient (amino acid)-stimulated glucagon secretion are two clearly different processes, differently affected by amylin. The balance of glucose fluxes is disturbed in diabetic states, partly as a result of inappropriate glucagon secretion. Although glucose production due to glucagon secreted in response to hypoglycemia is normal or even reduced in diabetic patients, the secretion of glucagon (and production of endogenous glucose) in response to protein meals is typically exaggerated. Absence of appropriate beta-cell suppression of alpha-cell secretion has been invoked as a mechanism that explains exaggerated glucagon responses, especially prevalent in patients with deficient beta-cell secretion (type 1 diabetes and insulinopenic type 2 diabetes). A proposed benefit of insulin replacement therapy is the reduction of absolute or relative hyperglucagonemia. High glucagon is said to be necessary for ketosis in severe forms of diabetes. A further benefit of reversing hyperglucagonemia is reduction of the excessive endogenous glucose production that contributes to fasting and postprandial hyperglycemia in diabetes. The idea that amylin is a part of the beta-cell drive that normally limits glucagon secretion after meals fits with the observation that glucagon secretion is exaggerated in amylin-deficient states (diabetes characterized by beta-cell failure). This proposal is further supported by the observation that postprandial glucagon suppression is restored following amylin replacement therapy in such states. These observations argue for a therapeutic case for amylin replacement in patients in whom excess glucagon action contributes to fasting and postprandial hyperglycemia and ketosis. The selectivity of amylin's glucagonostatic effect (wherein it is restricted to meal-related glucagon secretion, while preserving glucagon secretion and glucagon action during hypoglycemia) may confer additional benefits; the patient population amenable to amylin replacement therapy is likely to also be receiving insulin replacement therapy, and is thereby susceptible to insulin-induced hypoglycemia. Most explorations of the biology of amylin have used the endogenous hormone in the cognate species (typically rat amylin in rat studies). Clinical studies have typically employed the amylinomimetic agent pramlintide. Studies of amylinomimetic effects on glucagon secretion include effects of rat amylin in anesthetized non-diabetic rats (Jodka et al., 2000; Parkes et al., 1999; Young et al., 1995), effects of rat amylin in isolated perfused rat pancreas (Silvestre et al., 1999), effects of pramlintide in anesthetized non-diabetic rats (Gedulin et al., 1997b,c,d, 1998), effects of pramlintide in patients with type l diabetes (Fineman et al., 1997a,b,c,d, 1998a; Holst, 1997; Nyholm et al., 1996, 1997a,b,c; Orskov et al., 1999; Thompson and Kolterman, 1997), and effects in patients with type 2 diabetes (Fineman et al., 1998b). In addition, effects of amylin antagonists have been observed in isolated preparations (Silvestre et al., 1996), and effects of antagonists or neutralizing antibody have been determined in whole-animal preparations (Gedulin et al., 1997a,e,f).
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PMID:Inhibition of glucagon secretion. 1649 45

Several investigators have reported that more than half of African-American persons with new diagnoses of diabetic ketoacidosis have clinical, metabolic, and immunologic features of type 2 diabetes during follow-up. These patients are usually obese, have a strong family history of diabetes, have a low prevalence of autoimmune markers, and lack a genetic association with HLA. Their initial presentation is acute, with a few days to weeks of polyuria, polydipsia, and weight loss and lack of a precipitating cause of metabolic decompensation. At presentation, they have markedly impaired insulin secretion and insulin action, but intensified diabetic management results in significant improvement in beta-cell function and insulin sensitivity sufficient to allow discontinuation of insulin therapy within a few months of follow-up. On discontinuation of insulin therapy, the period of near-normoglycemic remission may last for a few months to several years. The absence of autoimmune markers and the presence of measurable insulin secretion have proven useful in predicting near-normoglycemic remission and long-term insulin dependence in adult patients with a history of diabetic ketoacidosis. This clinical presentation is commonly reported in African and African-American persons but is also observed in Hispanic persons and those from other minority ethnic groups. The underlying mechanisms for beta-cell dysfunction in ketosis-prone type 2 diabetes are not known; however, preliminary evidence suggests an increased susceptibility to glucose desensitization.
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PMID:Narrative review: ketosis-prone type 2 diabetes mellitus. 1652 Apr 76

The long-term complications of diabetes are the leading causes of morbidity and mortality in the type 1 diabetic population and remain a major public health issue. Hyperglycemia is one of the major risk factors in the development of vascular complications. A growing body of evidence indicates that hyperglycemia leads to increased oxidative stress and monocyte and endothelial cell dysfunction. In addition to hyperglycemia, type 1 diabetic patients frequently experience ketosis (hyperketonemia). The blood concentration of ketone bodies reaches higher than 25mM in diabetics with severe ketosis. Traditionally, clinical practice has considered hypertketonemia to be present only in type 1 diabetic patients. Newer data indicate that diabetic ketoaciosis or hyperketonemia co-exists with hyperglycemia among older type 2 diabetic patients and in African Americans and other minority groups with type 2 diabetes. This review will focus on the role of hyperketonemia in the etiology of oxidative stress in diabetic patients. The data presented here illustrate that the ketone body acetoacetate (AA) can generate superoxide radicals and cause increases in oxidative stress and cellular dysfunction. The data included in this review demonstrate that blood levels of markers of oxidative stress are elevated in hyperketonemic patients compared with those of normoketonemic diabetic patients. Thus, both in vitro and in vivo research indicate that ketosis can generate oxygen radicals and result in excess cellular oxidative stress in type 1 diabetic patients. Elevated oxidative stress levels in ketotic patients can play a significant role in the development of vascular inflammation and contribute to the increased incidence of vascular disease and complications associated with type 1 diabetes.
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PMID:Hyperketonemia (ketosis), oxidative stress and type 1 diabetes. 1678 14

The dietary effects of hyperglycemia increasingly result in type 2 diabetes in humans. Two species, the spiny mice (Acomys cahirinus) and the desert gerbil (Psammomys obesus), which have different metabolic responses to such effects, are discussed. Spiny mice exemplify a pathway that leads to diabetes without marked insulin resistance due to low supply of insulin on abundant nutrition, possibly characteristic of a desert animal. They respond with obesity and glucose intolerance, beta-cell hyperplasia, and hypertrophy on a standard rodent diet supplemented with fat-rich seeds. The accompanying hyperglycemia and hyperinsulinemia are mild and intermittent but after a few months, the enlarged pancreatic islets suddenly collapse, resulting in loss of insulin and ketosis. Glucose and other secretagogues produce only limited insulin release in vivo and in vitro, pointing to the inherent disability of the beta-cells to respond with proper insulin secretion despite their ample insulin content. On a 50% sucrose diet there is marked lipogenesis with hyperlipidemia without obesity or diabetes, although beta-cell hypertrophy is evident. P.obesus is characterized by muscle insulin resistance and the inability of insulin to activate the insulin signaling on a high-energy (HE) diet. Insulin resistance imposes a vicious cycle of Hyperglycemia and compensatory hyperinsulinemia, leading to beta-cell failure and increased secretion of proinsulin. Ultrastructural studies reveal gradual disappearance of beta-cell glucokinase, GLUT 2 transporter, and insulin, followed by apoptosis of beta-cells. Studies using the non-insulin-resistant HE diet-fed animals maintained as a control group are discussed. The insulin resistance that is evident to date in the normoglycemic state on a low-energy diet indicates sparing of glucose fuel in muscles of a desert-adapted animal for the benefit of glucose obligatory tissues. Also discussed are the effect of Psammomys age on the disabetogenicity of the HE diet; the impaired function of several components of the insulin signal transduction pathway in muscles, which reduces the availability of GLUT4 transporter; the testing of several antidiabetic modalities for the prevention of nutritional diabetes in Psammomys; and various complications related to the diabetic condition.
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PMID:Nutritionally induced diabetes in desert rodents as models of type 2 diabetes: Acomys cahirinus (spiny mice) and Psammomys obesus (desert gerbil). 1680 96


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