[Severe diabetes mellitus and hypokaliema revealing adrenocortical tumors].
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BACKGROUND: The sodium hydrogen exchanger (NHE) is a transmembrane protein responsible for alkalinization and control of intracellular acidosis by the removal of hydrogen and the subsequent influx of sodium. Our investigation attempts to determine the role of NHE-1 in the pathogenesis of early retinal microangiopathy due to diabetes. METHODS: Diabetes was induced in male Sprague-Dawley rats with a single intravenous streptozotocin injection (65 mg/kg). To examine the duration-dependent changes in NHE-1 expression, retinas from 1-, 6- and 12-week diabetic animals were analyzed. To examine the functional consequences of NHE-1 inhibition in comparison with good blood glucose control, diabetic rats were randomly assigned to poorly controlled diabetic, well-controlled diabetic, poorly controlled diabetic with cariporide groups and were compared with nondiabetic controls after six weeks. Cariporide is an orally active inhibitor of NHE-1 (6000 ppm in rat chow). At the end of the treatment period, color Doppler ultrasound was used to determine the resistivity index (RI) of the central retinal artery. The mRNA expression of endothelin (ET) isoforms 1 and 3, inducible and endothelial nitric oxide synthase (iNOS and eNOS respectively) and NHE-1 were examined. NHE-1 distribution was localized with immunohistochemistry. RESULTS: All diabetic animals showed hyperglycemia, increased glycated hemoglobin and lower body weight gain compared to nondiabetic controls. Diabetes caused an increased RI, indicative of retinal vasoconstriction, which was corrected by both cariporide treatment and good glucose control. NHE-1 was localized in the endothelium of the retinal microvasculature and the neuronal and glial components. NHE-1 mRNA expression was unchanged after 1 week and increased after 6 and 12 weeks of diabetes. Furthermore, a diabetes-induced upregulation of ET-1 and ET-3 mRNA expression after six weeks was corrected with cariporide treatment. NHE-1 inhibition of diabetic animals upregulated iNOS mRNA levels, although expression of eNOS and iNOS mRNA were not altered in poorly controlled diabetes. Improved blood glucose control with higher doses of insulin also corrected diabetes-induced increased RI by upregulating eNOS and iNOS mRNA expression. CONCLUSIONS: The results of the study suggest that NHE-1 may be involved in the regulation of several vasoactive modulators that contribute to functional alterations in diabetic retinal microangiopathy.
Metformin is an oral antihyperglycemic agent used in the therapy of noninsulin-dependent diabetic patients. This biguanide can induce dangerous complications such as lactic acidosis when its plasma concentration is too high. For this reason, the determination of plasma metformin should always be done during treatment. We developed a new HPLC method, for the routine determination of plasma metformin, with good reliability, rapid execution, and low costs. Sample preparation involved precipitation of the plasma proteins containing the internal standard buformin with a mixture of methanol, zinc sulfate, and ethylene glycol; the diluted supernatant was injected into a cation-exchange column. The mobile phase was potassium dihydrogenphosphate buffer-containing acetonitrile. The eluent was monitored at 236 nm. The calibration curve is linear within the range of 20-4000 ng/mL; the within-day coefficients of variation were less than 2.2% for metformin and 1.5% for buformin; the day-to-day coefficients of variation were less than 2.5% for metformin and 1.9% for buformin. The mean recoveries obtained from supplemented samples were included between 99.4 and 104.2% for metformin. Many characteristics make this method useful and easily accessible to all clinical laboratories equipped with HPLC instrumentation.
Administration of decanoic acid to rats resulted not only in elevated urinary excretions of the C10-dicarboxylic acid (sebacic acid), but also in highly elevated excretions of the beta-oxidation products C8- and C6-dicarboxylic acids (suberic and adipic acids). Activation of the lipid metabolism by starvation, fat-feeding and experimental diabetes increased the excretions of adipic acid and decreased the excretions of sebacic acid, i.e. the rate of oxidation of fatty acids was correlated to the adipic : sebacic acid ratio in urine. Compared with nondiabetic unstarved rats the adipic : sebacic acid ratio was elevated 2--3-, 8--16-, 5--19-, and 22--88-times in rats which were, respectively, starved for 2 days, 4 days, on a fat-diet for 4 days, and ketotic due to streptozotocin-induced diabetes. All rats with ratios above 10 were ketotic (urinary excretions of 3-hydroxybutyric acid over 500 microgram/mg creatinine) and all rats with ratios below 4 were nonketotic, while ketosis was a variable finding in rats with intermediary ratios. Similar changes in the ratio of excreted dicarboxylic acids were found when medium-chain triacylglycerols were fed instead of decanoic acid.
The study was designed to evaluate hepatic mitochondrial function during ketotic states. The ketogenic models studied were streptozotocin-induced diabetic ketoacidosis, 48 h of starvation, and after growth hormone administration. In the last-mentioned model we observed increased free fatty acids but not ketonemia. Oxidative phosphorylation was measured using the citric acid cycle substrates pyruvate and succinate, the amino acid glutamate, a ketone body beta-hydroxybutyrate, and a long-chain fatty acid palmitoyl-l-carnitine. State 3 (ADP stimulated) and state 4 (ADP limited) respiration, respiratory control ratio (state 3/state 4), and the ADP/O ratios were normal in the controls and the experimental groups. Uncoupled respiration produced by dinitrophenol with a variety of substrates was unchanged in the experimental groups compared to the controls. Fatty acid oxidation was studied in detail. The rate of utilization of palmitoyl-l-carnitine by controls or experimental groups did not depend on the product formed (citrate, acetoacetate). No significant changes were observed in the oxidation of palmitoyl-CoA (+ carnitine) or with an intermediate-chain fatty acid hexanoate. The specific activity of hepatic mitochondria carnitine palmitoyltransferase did not change in any of the three experimental groups. It is concluded that during diabetic ketoacidosis, starvation, and growth hormone administration, there is (a) no alteration in hepatic mitochondrial function; (b) no change in the intrinsic capacity of hepatic mitochondria to oxidize fatty acids; and (c) no change in the specific activity of mitochondrial carnitine palmitoyltransferase. The mechanism by which the body restrains flux through the mitochondrial oxidative machinery remains to be fully determined.
OBJECTIVE: Cardiac impairment is frequently found in babies of diabetic mothers. It is still controversial whether this is due to poor glucose control. The aim of this study is to compare the cardiac function in fetuses of well- and poorly-controlled pre-gestational diabetic pregnancy in third trimester. METHODS: Women with type 1 pre-gestational diabetes were enrolled at 30-32 weeks. Cardiac size and interventricular septal wall thickness were measured by M-mode at end-diastolic phase. The right and left ventricular ejection fractions were calculated. At the mitral and tricuspid valves inflow, the ratio between early ventricular filling and active atrial filling (E/A) at both atrioventricular valves were measured by Doppler echocardiography. Peak velocities of ascending aorta and pulmonary artery were assessed. The angle of isonation was kept at <20 degrees. Women with poorly-controlled diabetes (HbA1c>6.5%) were compared with those with satisfactorily controlled diabetes (HbA1c < or = 6.5%). RESULTS: A total of 21 women with pre-gestational diabetes were recruited for this study. Eight women with well-controlled diabetes were compared with 9 women who had poorly-controlled diabetes. HbA1c in the poorly-controlled group was 7.3% and in the well-controlled group it was 5.4% (p<0.001). There was no difference between the two groups in cardiac size, interventricular septal wall thickness, ejection fraction, aorta and pulmonary artery peak flow velocities. The right atrioventricular E/A ratio was significantly lower among the poorly-controlled diabetic pregnancies (0.71 vs. 0.54; p<0.05). CONCLUSION: Fetuses of poorly-controlled diabetic mothers had a lower right atrioventricular E/A ratio. This may be due to metabolic acidosis, non-hypertrophic cardiac dysfunction or fetal polycythemia.
Metabolic acidosis is a common complication in patients after kidney transplantation. It is caused by inability of transplanted kidney to regenerate bicarbonate buffer. Although every type of acidosis may be present in these patients, the most frequent are renal tubular acidosis and uremic acidosis. Both insufficiency of graft and tubular dysfunction can be caused by ischemic damage, episodes of rejection and cyclosporine A--induced nephrotoxicity. Ketoacidosis due to a post-transplant diabetes mellitus and bicarbonate loss in patients after simultaneous pancreas/kidney transplantation are rarely observed. Each type of acidosis is responsible for serious metabolic disturbances that influence graft and patient survival. The proper diagnosis and appropriate treatment with oral supplements are essential.
The classic proposal of intracellular K+ for extracellular H+ exchange as responsible for the hyperkalemia of diabetic ketoacidosis (DKA) has been questioned because experimentally induced organic anion acidosis fails to produce hyperkalemia. It has been suggested, instead, that the elevated serum [K+] of DKA might be the result of the compromised renal function, secondary to volume depletion, that usually accompanies DKA. However, several metabolic derangements other than volume depletion and acidosis, which are known to alter potassium metabolism, also develop in DKA. This study of 142 admissions for DKA examines the possible role of alterations in plasma pH, bicarbonate, glucose (G), osmolality, blood urea nitrogen (BUN) and plasma anion gap (AG) on the levels of [K+]p on admission. Significant (p less than 0.01) correlations of [K+]p with each of these parameters were found that could individually account for 8 to 15 percent of the observed variance in the plasma potassium levels; however, the effects of some or all of these parameters on the [K+]p could be independent and therefore physiologically additive. Since the parameters under study are themselves interrelated, having statistically significant correlations with each other, their possible independent role on [K+]p was evaluated by multiple regression analysis. Only plasma pH, glucose and AG emerged as having a definite independent effect on [K+]p, with no independent role found for bicarbonate, BUN and osmolality. The equation that best describes [K+]p on admission for DKA was: [K+]p = 25.4 - 3.02 pH + 0.001 G + 0.028 AG, (r = 0.515). These results indicate that the endogenous ketoacidemia and hyperglycemia observed in DKA, which result primarily from insulin deficit, are the main determinants of increased [K+]p. Since exogenous ketoacidemia and hyperglycemia in the otherwise normal experimental animal do not increase [K+]p, it is postulated that insulin deficit itself may be the major initiating cause of the hyperkalemia that develops in DKA. Renal dysfunction by enhancing hyperglycemia and reducing potassium excretion also contributes to hyperkalemia.
The acid-base and electrolyte balance of 30 women studied at delivery and in their infants during the first 48 h. 18 women were diabetics, 10 of these were delivered vaginally (DMvag) and 8 by elective caesarean section (DMcs). 12 healthy women were vaginally delivered (HMvag). The infants of diabetic mothers (IDM) received active infusion therapy. At birth the DMvag and their infants (IDMvag) had a more pronounced metabolic acidosis than the DMcs and their babies (IDMcs). The largest metabolic acidosis occurred, however, in the group of HMvag and their infants (IHMvag). After birth no significant differences were obtained in the acid-base and electrolyte balance between IDMvag and IDMcs. The plasma potassium level remained lower in IDM than in IHM. The study stress the importance of adequate management of diabetes in pregnancy in combination with active intravenous therapy during delivery and to the infant in the immediate neonatal period. The slightly larger metabolic acidosis seen in combination with vaginal delivery suggests that this mode of delivery should not be attempted uncritically in diabetic women.
Diabetic ketoacidosis results from insulin deficiency and insulin resistance and is marked by hyperglycaemia, ketoacidosis, dehydration and electrolyte losses. Management includes correction of shock, dehydration, electrolyte deficits, hyperglycaemia, acidosis and sepsis (if present). Warning signs include severe dehydration, shock, pH < 7.0, hypokalaemia, hypernatraemia, hyperosmolality, hyperlipidaemia, deterioration in consciousness and diabetic ketoacidosis in very young patients. The principles of treatment include (i) admission to a unit with paediatric experience, (ii) treatment of shock, (iii) rehydration over 24-36 h, or longer if the osmolality is >360 mmoll(-1), (iv) normal saline for rehydration unless the patient is hypernatraemic, (v) avoidance of bicarbonate unless acidosis is interfering with myocardial contractility, (vi) insulin infusion to achieve a fall in blood glucose levels of 5 mmol h(-1), (vi) potassium, (vii) use of 5% glucose when the blood glucose level falls <12mmoll(-1), (ix) treatment of any complications and (x) change to subcutaneous insulin when diabetic ketoacidosis is controlled.
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BioBreed (BB) Wistar rats develop diabetes mellitus, which closely resembles the human disease, in 50% of progeny. Intestinal sucrase-alpha-dextrinase, a glycoprotein hydrolase of the enterocyte's brush border consisting of 140-kDa alpha-dextrinase and 125-kDa sucrase subunits, is essential for surface digestion of carbohydrate nutrients. Although its catalytic characteristics were found to be maintained in the diabetic state, the structure of the subunits, as compared with normal Wistar rats, was altered in the BB rat within 2 days of the onset of diabetes. Its capacity to react in a solid-phase immunoassay was reduced by 50%; when examined by 6% acrylamide electrophoresis, the sucrase subunit was increased in mass by 5 kDa and, in some BB rats, the dextrinase subunit was reduced by 5 kDa. Intact rats labeled intraintestinally with [35S]methionine displayed the alteration within 6 h of synthesis, indicating that nonenzymatic glycosylation could not account for the structural change. This mass change was not seen in streptozotocin-induced diabetes and was independent of the plasma glucose concentration or the degree of acidosis. Deglycosylation with peptide N-glycosidase indicated that the N-linked chains of the normal dextrinase subunit (11 kDa) have twice the mass of those in the BB rat (6 kDa) and that the sucrase subunit may have an increased mass of O-linked chains. Overall, these experiments point to changes in glycosylation as a mechanism of structural alteration in congenital diabetes. Despite persistence of the insulin-dependent diabetes, the subunit pattern eventually became indistinguishable from normal, but at differential rates (21 days and 35 days, respectively, for sucrase and dextrinase subunits).
Although hypophosphatemia is a common complication during therapy of diabetic ketoacidosis, it is seldom severe and rarely causes clinical manifestations. We report a 39-year-old woman with diabetic ketoacidosis who developed acute respiratory failure after therapy. Although hyperglycemia and acidosis were corrected after treatment, respiratory distress and weakness still persisted. The chest radiograph showed no active lung lesion. Brain CT revealed no significant abnormality. Echocardiographic study revealed normal LV systolic wall motion. Blood biochemistry demonstrated severe hypophosphatemia of 0.3 mg/dL (normal value: 2.5 to 4.5 mg/dL). Phosphate replacement therapy with potassium phosphate was given. The patient's clinical condition improved steadily over the next few days, and after 4 weeks of hospitalization, she was discharged home without obvious long-term sequelae. In a critically ill patient, the symptoms of hypophosphatemia are not apparent and may mimic the symptoms of other underlying disease. Although phosphate replacement is not recommended routinely in diabetic ketoacidosis, if the patient develops cardiopulmonary distress, anemia or severe hypophosphatemia, phosphate therapy under close surveillance is indicated.
BACKGROUND AND PURPOSE: We determined the effect of chronic hyperglycemia associated with diabetes on recovery of cerebral pH after global incomplete cerebral ischemia. METHODS: 31P magnetic resonance spectra and cerebral blood flow (radiolabeled microspheres) were measured in three groups of dogs: (1) chronic hyperglycemic diabetes (pancreatectomy followed by blood glucose > 10 mmol/L for 3 months; n = 8); (2) acute hyperglycemia during ischemia and reperfusion in nondiabetic dogs (n = 8); and (3) normoglycemic controls (n = 8). Incomplete ischemia was produced for 20 minutes by ventricular fluid infusion followed by 3 hours of reperfusion. RESULTS: Cerebral blood flow was reduced to approximately 5 mL/min per 100 g in all groups during ischemia with individual values ranging from 1 to 11 mL/min per 100 g. Blood flow returned to preischemic values by 30 minutes of reperfusion in the normoglycemia group but remained elevated during reperfusion in the acute hyperglycemia and diabetes groups. Cerebral pH at the end of ischemia was lower in acute hyperglycemia (5.94 +/- 0.05; +/- SE) and diabetes (5.97 +/- 0.08) groups than in the normoglycemia group (6.27 +/- 0.02). However, recovery of pH through 90 minutes of reperfusion in the normoglycemia (7.08 +/- 0.05) and diabetes (7.00 +/- 0.04) groups was significantly greater than in the acute hyperglycemia group (6.74 +/- 0.11). Persistent acidosis in the acute hyperglycemia group was associated with a delayed reduction of cerebral oxygen consumption and high-energy phosphates and with greater cortical water content and impairment of somatosensory evoked potentials compared with the diabetes group. CONCLUSIONS: This study shows that cerebral pH recovery after global incomplete ischemia is improved in chronic hyperglycemia compared with acute hyperglycemia, despite similar decreases in blood flow and pH during ischemia and similar levels of blood flow and glucose levels during ischemia and reperfusion. In addition, cerebral pH recovery in chronic hyperglycemic dogs was not different from that in normoglycemic controls. These results suggest that an adaptation occurs with chronic hyperglycemia that improves recovery of cerebral pH during reperfusion and that is associated with better maintenance of energy metabolism and evoked potentials and with less edema over 3 hours of reperfusion compared with acute hyperglycemia.
A patient with a Lowe syndrome was observed from birth. Progressive hyperchloraemic renal tubular acidosis, hypophosphataemia, hyperphosphaturia and generalized hyperaminoaciduria had developed in infancy. Supplementary vitamin D, alkali and a high intake of dietary phosphate were unsuccessful in controlling the severe phosphate diabetes and rickets. Contraction of the extracellular fluid volume by dietary sodium restriction resulted in correction of the acidosis, hypophosphataemia, hyperaminoaciduria, and hyperphosphaturia, and healing of the rickets.
A consanguinous couple had a healthy boy and 2 children, a girl and a boy, with distal renal tubular acidosis and sensory nerve deafness. In addition, the girl had congenital glaucoma and malformation of the iris; the boy developed Wilms tumor and insulin-dependent diabetes mellitus. The possible significance of these associations is discussed.
Diabetic ketoacidosis (DKA) is the most common hyperglycemic emergency in patients with diabetes mellitus. DKA most often occurs in patients with type 1 diabetes, but patients with type 2 diabetes are susceptible to DKA under stressful conditions, such as trauma, surgery, or infections. DKA is reported to be responsible for more than 100 000 hospital admissions per year in the US, and accounts for 4-9% of all hospital discharge summaries among patients with diabetes. Treatment of patients with DKA uses significant healthcare resources and accounts for 1 out of every 4 healthcare dollars spent on direct medical care for adult patients with type 1 diabetes in the US. Recent studies using standardized written guidelines for therapy have demonstrated a mortality rate of less than 5%, with higher mortality rates observed in elderly patients and those with concomitant life-threatening illnesses. Worldwide, infection is the most common precipitating cause for DKA, occurring in 30-50% of cases. Urinary tract infection and pneumonia account for the majority of infections. Other precipitating causes are intercurrent illnesses (i.e., surgery, trauma, myocardial ischemia, pancreatitis), psychological stress, and non-compliance with insulin therapy. The triad of uncontrolled hyperglycemia, metabolic acidosis and increased total body ketone concentration characterizes DKA. These metabolic derangements result from the combination of absolute or relative insulin deficiency and increased levels of counter-regulatory hormones (glucagon, catecholamines, cortisol, and growth hormone). Successful treatment of DKA requires frequent monitoring of patients, correction of hypovolemia and hyperglycemia, replacement of electrolyte losses, and careful search for the precipitating cause. Since the majority of DKA cases occur in patients with a known history of diabetes, this acute metabolic complication should be largely preventable through early detection, and by the education of patients, healthcare professionals, and the general public. The frequency of hospitalizations for DKA has been reduced following diabetes education programs, improved follow-up care, and access to medical advice. Novel approaches to patient education incorporating a variety of healthcare beliefs and socioeconomic issues are critical to an effective prevention program.
Recent experiments from our laboratory have documented the importance of ammonia as a modulator of renal cell growth in vitro. Ammonia induces renal hypertrophy by increasing the rate of protein synthesis and decreasing the rate of protein degradation. These results have led to the hypothesis that an increase in renal ammoniagenesis contributes to renal growth in several seemingly unrelated clinical disorders. In chronic hypokalemia and metabolic acidosis, mitochondrial ammoniagenesis is stimulated directly. During protein loading, uninephrectomy, and diabetes mellitus, renal ammoniagenesis may be stimulated by an increase in single-nephron glomerular filtration rate (SNGFR).