Common reabsorption system of 1,5-anhydro-D-glucitol, fructose, and mannose in rat renal tubule.

1,5-Anhydro-D-glucitol (AG) is a major polyol, 99.9% of which is reabsorbed by the kidney. However, such reabsorption is inhibited by competition with glucose excreted in excess, i.e., glucosuria. Under such conditions, AG is excreted into the urine. We administered various types of sugars to rats by continuous intravenous infusion for two hours to evaluate the competition between AG and these sugars for renal reabsorption in vivo. The reabsorption of AG was significantly inhibited by competition with fructose and mannose. The excretion of AG in the 120 min after a load of 3.64 mmol of fructose was 1.99 +/- 0.33 mumol, that after 3.64 mmol of mannose loading was 2.34 +/- 0.43 mumol. These levels were comparable to the AG excretion observed after the administration of the same amount of glucose (3.87 +/- 0.61 mumol). No competition was observed with sucrose, xylose, myoinositol or galactose. The reabsorption of fructose and mannose was significantly inhibited by the presence of AG (P < 0.001) after a mixed load. Results suggest that AG is reabsorbed in the renal tubule by an AG/fructose/mannose-common transport system that is distinct from the major glucose reabsorption system. These findings may help to clarify the specific transport systems for various sugars in the renal tubule, as well as their physiological importance.

Transport of 1,5-anhydro-D-glucitol into insulinoma cells by a glucose-sensitive transport system.

The uptake of 1,5-anhydro-D-glucitol (1,5-AG) occurs by passive mechanisms in cells or tissues that have passive glucose transporters. It is known that serum 1,5-AG concentrations are reduced in patients with diabetes mellitus. To elucidate the metabolism of this substance and its physiological role in pancreatic beta-cells, we assayed 1,5-AG transport in the insulinoma-derived cell lines, RINr and MIN6. Both cell lines showed an insulin-insensitive, concentration-dependent uptake of 1,5-AG with a saturation time of approximately 120 min, and most of the 1,5-AG in the cytoplasm was in the free form. A biphasic saturation curve was obtained using a wide range of 1,5-AG concentrations, suggesting that accumulation was mediated by a high affinity and a low affinity transporter. The high affinity transporter had a K(m) of 10.4 in RINr cells and 13.0 mM in MIN6 cells, and the low affinity transporter had a K(m)100 times, being much higher than the physiological concentrations of 1,5-AG. These results indicate that the 1,5-AG carrier system in insulinoma cells is distinct from that in either the somatic cells or renal tubular cells. These findings also suggest that a unique 1,5-AG transport system is present in pancreatic beta-cells.

Marked depletion of plasma 1,5-anhydroglucitol, a major polyol, in streptozocin-induced diabetes in rats and the effect of insulin treatment.

Plasma levels of 1,5-anhydroglucitol (1,5AG), a major polyol resembling glucose in structure, fell rapidly and dramatically in streptozocin (STZ)-treated rats. 1,5AG fell immediately after STZ injection, reaching a plasma level 6 h after administration of the drug that was one-third that in the plasma of control rats. Reduction of 1,5AG was independent of the profile of blood glucose induced by STZ. After intravenous injection of [14C]-1,5AG, its plasma half-life was determined to be between 120 and 180 min. After a phase of acute decrease, the reduction of 1,5AG became gradual, stopping within 6 days after treatment. However, in some cases, the drop in 1,5AG was partially reversible by insulin treatment. The extent to which 1,5AG fell did not strictly correspond to the dose of STZ. The particular organ(s) consuming or accumulating 1,5AG was not identified. However, aside from the large amount of 1,5AG in plasma and the small amount of 1,5AG in the urine, the liver appears to be a significant organ for metabolism of 1,5AG.

Reduction and recovery of plasma 1,5-anhydro-D-glucitol level in diabetes mellitus.

The plasma concentration of 1,5-anhydro-D-glucitol (AG) was measured in 135 newly diagnosed patients who were referred for oral glucose tolerance tests. AG concentrations in the nondiabetic patients indicated that the mean value of normal AG concentration was 21.8 micrograms/ml (SD = 5.9 micrograms/ml, range 9.6-38.8 micrograms/ml). This distribution of AG concentration was significantly different from that in patients with impaired glucose tolerance (IGT) (13.3 +/- 5.4 micrograms/ml) and definitely different from that in diabetic patients (2.1 +/- 1.8 micrograms/ml). In a standard glucagon test, it was suggested that the decrease of plasma AG was affected not only by glycemic control of the patients but also by pancreatic cell secretory activity. The reduction of AG concentration was more marked in IDDM patients than in NIDDM patients. In longitudinal studies, AG concentration was shown to be sensitive to glycemic control. However, its recovery showed a tendency toward much delay after the improvement of fasting blood glucose or HbA1 concentrations. On the other hand, AG concentration showed negligible diurnal change and no immediate change as a result of diet, oral glucose load, or acute shift of the insulin level in both normal and diabetic subjects.

Characteristics of insulin receptors and insulin action in human myelogenous leukemia cell line K-562.

Specific binding sites for insulin have been identified and characterized for the human erythroleukemia cell line K-562. The binding of [125I]-insulin to the cells increased as a function of time, reaching a maximum at 20 min when incubation was performed at 37 degrees C. The binding of [125I]-insulin was dose-dependently inhibited by insulin or proinsulin. Scatchard plot of the binding data was curvilinear, and the number of insulin receptors was approximately 39,000. Insulin at concentrations of 0.05-10.0 ng/ml stimulated CO2 production and DNA and protein synthesis in K-562 cells in a dose-dependent manner, indicating that the insulin binding sites are functionally important in mediating these biochemical events induced by insulin. Maximal insulin responses were elicited at concentrations of less than 5 ng/ml, when (at most) 10% of the insulin receptors were occupied. After binding to the cells, [125I]-insulin was degraded in a time- and temperature-dependent manner. As reported for other types of cells, unlabeled insulin also downregulated insulin receptors in K-562 cells. When the cells were incubated with 1 X 10(-7) M unlabeled insulin for 24 h, the number of insulin receptors decreased by 50% without a change of affinity. K-562 cells may be useful in studying the role of insulin receptors in cell functions induced by insulin.

Plasma 1,5-anhydro-D-glucitol as new clinical marker of glycemic control in NIDDM patients.

To elucidate the value of using plasma 1,5-anhydro-D-glucitol (AG) as a marker of glycemic control in diabetic patients, the relationship between the plasma concentration of AG and glucosuria was examined in 152 patients with non-insulin-dependent diabetes mellitus (NIDDM). After recovery from the deterioration of glycemic control in NIDDM patients had started, AG began to increase day by day. The recovery of plasma AG showed a constant linear increase curve when excellent glycemic control was attained. The ordinary daily recovery rate of plasma AG was estimated to be 0.3 microgram/ml, which was independent of body weight, sex, age, the difference in treatment, the duration of diabetes, or the level of plasma AG among NIDDM patients. This rate decreased according to the increase in urinary glucose. When we calculated the decrease rate of plasma AG (delta AG), assuming 0.3 microgram/day to be the maximum increase rate in a day, we found a high correlation between delta AG and urinary glucose at almost all AG levels except the normal range and observed that plasma AG (A) times urinary glucose (G) was relatively constant. The formula A x G = 16 is a simple equation for rough estimation of urinary glucose from the plasma AG concentration in a stable glycemic-controlled NIDDM patient, and we call it the A.G index. The plasma AG also correlated significantly with fasting plasma glucose (r = -.810) and glycosylated hemoglobin (r = -.856) in the same stable glycemic-controlled NIDDM patients. Based on these observations, we propose that plasma AG can serve as a new marker that may provide sensitive and analytical information about glycemic control.

Comparison of 1,5-anhydroglucitol, HbA1c, and fructosamine for detection of diabetes mellitus.

To evaluate the use of serum 1,5-anhydroglucitol (AG) levels in screening for diabetes mellitus, we compared the sensitivity and specificity of HbA1c, fructosamine (FA), and AG in 1620 randomly selected subjects in 11 institutions throughout Japan. Most individuals were receiving diet and/or drug therapy for diabetes. Subjects were separated into four groups based on World Health Organization criteria: nondiabetic control subjects, subjects with impaired glucose tolerance (IGT), patients with diabetes, and patients with other disorders without IGT. The overlap of AG values between each group was less than that of HbA1c or FA values. AG levels were significantly correlated with fasting plasma glucose (r = -0.627), HbA1c (r = -0.629), and FA (r = -0.590) levels. If we took 14 micrograms/ml as the normal lower limit, AG level was highly specific (93.1%), and a decreased AG level indicated diabetes mellitus (84.2% sensitivity). According to the selectivity index (sensitivity value times specificity value), AG determinations were superior to both HbA1c and FA measurements for diabetes screening. When combinations of these tests were used, only AG and HbA1c together were slightly better than AG alone. Thus, together with other advantages of AG, e.g., its wide variance with relatively fair glycemic control and the negligible influence of the sampling conditions, AG level has more potential than HbA1c or FA level as a screening criterion for diabetes.

Esophageal atresia with double tracheoesophageal fistula--a case report and review of the literature.

Esophageal atresia with double tracheoesophageal fistula (TEF) is a very rare anomaly, and the accurate preoperative diagnosis of proximal TEF is very difficult. This paper describes a baby girl who presented with esophageal atresia with double, proximal, and distal TEF. The distal TEF was diagnosed before operation, whereas the proximal TEF was found intraoperatively. Overlooking the presence of proximal TEF can lead to increased morbidity and mortality due to severe respiratory infection and the necessity of a second operation. Great care must therefore be taken to not overlook the presence of proximal TEF in patients with this anomaly.

Relationship between serum 1,5-anhydroglucitol and urinary excretion of N-acetylglucosaminidase and albumin determined at onset of NIDDM with 3-year follow-up.

OBJECTIVE: This prospective study was designed to elucidate the relationship between the serum level of 1,5-anhydroglucitol (1,5AG) and the urinary excretion of N-acetylglucosaminidase (NAG) and albumin in patients who were in the early stages of diabetes. RESEARCH DESIGN AND METHODS: A total of 1,062 male nondiabetic subjects with impaired glucose tolerance were monitored for blood glucose level once every 2-3 months, and the values were evaluated. Of these 1,062 subjects, 112 showed a worsening of glycemia during the observation period to the level seen in diabetes. We began to monitor the glycemia and parameters of renal damage in the 112 patients from the onset of diabetes. RESULTS: The urinary excretion of NAG and albumin were elevated even at the onset of diabetes. The abnormal excretion of NAG and albumin was associated with a change in serum 1,5AG and was quickly reversible when the serum 1,5AG improved. In the 3 years after the onset of diabetes, we obtained at least 18 measurements of one parameter for each patient and calculated the mean. Urinary NAG was found to be significantly correlated with the fasting plasma level of glucose (FPG; r = 0.512, P < 0.0001), the level of HbA1 (r = 0.351, P = 0.001), and the level of 1,5AG (r = -0.790, P < 0.0001). The urinary excretion of albumin was weakly but significantly correlated with levels of FPG (r = 0.383, P < 0.0001) and HbA1 (r = 0.337, P < 0.0001), but it was more strongly correlated with 1,5AG (r = -0.632, P < 0.0001). The level of 1,5AG was significantly correlated with FPG (r = -0.681, P < 0.0001) and HbA1 (r = -0.609, P < 0.0001). CONCLUSIONS: When the renal damage is not severe, the serum level of 1,5AG appeared to be an indicator of the reversible renal damage caused by hyperglycemia, as well as of the severity of the glycemia itself.

New powerful insulin-like protein from human promyelocytic leukemia cells.

Potent insulin-like activity was found in the conditioned medium of human promyelocytic leukemia (HL-60) cells. The conditioned medium of HL-60 cells at high density stimulated [3H]glucose incorporation into lipids in rat adipocytes in a time- and dose-dependent manner. The dose-response curve for this factor was not parallel to that for insulin, and the maximal effect achieved was much greater than reached by insulin or multiplication-stimulating activity. Moreover, the maximal effect reached by either insulin or the conditioned medium was additive. The insulin-like activity was not suppressed in the presence of antiinsulin antibody. Insulin-like activity was not detectable by radioreceptor assay for insulin, suggesting that the factor does not act through the insulin receptor. The factor in the conditioned medium of HL-60 cells was heat stable and sensitive to trypsin. When the conditioned medium was subjected to gel filtration on a Sephadex G-100 column, the major part of insulin-like activity eluted in the position corresponding to an apparent molecular weight between RNAase and insulin markers. The remaining activity, approximately 10% of the total, appeared with a larger molecular weight species. On isoelectric focusing of the smaller molecular species, insulin-like activity was largely focused in the position corresponding to pI 7.8-8.2.

Reduced renal reabsorption of 1,5-anhydro-D-glucitol in diabetic rats and mice.

A stable amount, approximately 60 micrograms, of 1,5-anhydro-D-glucitol (AG) was detected in the 24-h-urine of normal young rats fed ad libitum. Upon administration of streptozotocin (STZ), this amount was temporarily elevated to as much as 1.1 mg and AG was concomitantly removed from the circulation. The plasma AG level stayed almost null thereafter while the acutely elevated urinary AG excretion declined within 24 h to another stable excretion level that was three times as high as that of the untreated rats. In contrast, glucosuria developed much more slowly in the drug-treated rats. Normal rats and mice retained exogenous [14C]AG to a considerable extent and the radioactivity was distributed all over the body. Only a marginal fraction of the radioactivity was excreted as expired CO2. The radio-activities retained in the body and excreted into the urine were mostly attributed to unmetabolized AG. The observations of AG's metabolic stability and its relatively low level of leakage into urine suggested the concept of effective renal AG reabsorption. On the other hand, the rats with STZ-induced diabetes and NOD-mice with spontaneously developed diabetes retained little of the radioactive AG in their bodies; most of the injected radioactivity was recovered in the urine within 24 h. This observation was interpreted as due to reduced renal AG reabsorption in these animals. The concept of reduction in renal AG reabsorption in diabetes could account for the reduced plasma AG level generally observed in human diabetic cases.

Sorbitol determination by liquid chromatography: application to red blood cells of diabetic rats.

This report describes an application of liquid chromatography to the determination of sorbitol in red blood cells. The chromatograph employed in the present study was made up of sub- and main-separation systems and a detector portion. The sub-separation system was for concentration of polyols and involved two small columns, each containing the same anion exchange resin. The first was a tiny column which, in borate form, served as the concentrator of polyols and sugars charged in a large volume, while the second, in acetate form, separated the carbohydrates from the borate. The main system was for the fine separation of each carbohydrate and employed cation exchange columns. The detector part utilized a flow fluorometric method comprising two successive reactions: periodate oxidation followed by the Hantzsch reaction. The resulting whole chromatographic system was applied to the determination of sorbitol in red blood cells obtained from normal rats and rats made diabetic by the administration of streptozotocin; a part of the latter group had also received an aldose reductase inhibitor. Our results supported the concepts that a prolonged duration of high blood glucose level induces an elevated level of sorbitol inside red blood cells and that aldose reductase inhibitors are effective in reducing this level.

Estimation of plasma glucose fluctuation with a combination test of hemoglobin A1c and 1,5-anhydroglucitol.

We investigated the effect of plasma glucose fluctuation on hemoglobin A1c (HbA1c) and plasma 1,5-anhydroglucitol (AG) levels, especially in insulin-dependent diabetes mellitus (IDDM). Plasma AG is a new marker that provides sensitive and analytical information on glycemic control. The basic mechanisms underlying both the reduction and recovery of the plasma AG level, ie, the excretion into urine with glucosuria and the amount supplied to the body, were presumed to be similar in IDDM and non-insulin-dependent diabetes mellitus (NIDDM) patients. The correlation coefficient for mean plasma glucose and AG was -.591, and it was .578 for mean plasma glucose and HbA1c in IDDM patients. In NIDDM, the correlation between mean plasma glucose and AG was -.869, and between mean plasma glucose and HbA1c, .875. The plasma AG levels in the IDDM group showed a lower range than in the NIDDM group, even with similar HbA1c levels. All the cases showing lower plasma AG levels among those with similar HbA1c levels manifested greater fluctuation of plasma glucose and a larger amount of urinary glucose. The lower AG level in IDDM patients was reversible to the level in NIDDM patients when the greater fluctuation of plasma glucose was corrected. Thus, it was suggested that because urinary glucose excretion is intermittently high in IDDM patients, plasma AG is frequently low, even though the mean plasma glucose and HbA1c levels suggest good control.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of diabetes by thymic hormone in alloxan-treated rats.

We investigated the effects of facteur thymique sérique (FTS), a thymic peptide hormone, on alloxan- and streptozotocin-induced diabetes in rats. Pretreatment with intravenous injection of FTS significantly suppressed both alloxan- and streptozotocin-induced hyperglycemia. The effects of FTS were time dependent. FTS suppressed hyperglycemia in a dose range of 1-6600 micrograms/kg. Alloxan-induced hyperglycemia was completely prevented when FTS was injected in doses of 40-50 micrograms/kg 1 min before injection of alloxan. Histological examination of islet areas showed that alloxan-induced destruction of beta-cells was inhibited by FTS. FTS had no significant effects on lymphocyte subsets and immunity-related cells or on plasma superoxide dismutase activity and total glutathione level. The blood half-life time of exogenously injected FTS was short (2-3 min), indicating acute internalization of FTS into pancreatic beta-cells. Our results suggested that FTS acutely and directly blocks some initial effect of alloxan, preventing the destruction of beta-cells.

Acute glucosuria after continuous glucocorticoid loading in the rat in vivo.

We investigated the effects of the continuous infusion of various steroids in rats on renal tubular reabsorption of glucose in vivo to elucidate the pathogenesis of steroid-induced glucosuria. Urinary glucose excretion increased 60 min after administration of dexamethasone (2.38 mM). By 120 min, urinary excretion of glucose was three times higher in the dexamethasone group than in the control group (24.1 +/- 4.6 versus 72.4 +/- 16.7 micromol); the plasma level of glucose did not increase. Dexamethasone had no effect on the resorption of 1,5-anhydro-D-glucitol, which is a glucose-resembling polyol that is actively absorbed by the renal tubules as glucose. Neither estradiol nor progesterone increased urinary excretion of glucose. These findings suggest that continuous administration of a high-dose glucocorticoid selectively influences the glucose reabsorption system in the kidney.

Serum 1,5-anhydroglucitol (1,5 AG): new clinical marker for glycemic control.

We review the use of 1,5-anhydroglucitol (1,5 AG) in diagnosing and monitoring patients with diabetes. This six-carbon chain monosaccharide is one of the major polyols present in humans. Its concentration in serum is normally about 12 to 40 micrograms/ml. This substance is derived mainly from food, is well absorbed in the intestine, and is distributed to all organs and tissues. It is metabolically stable, being excreted in the urine when its level exceeds the renal threshold. It is reabsorbed in the renal tubules, and is competitively inhibited by glucosuria, which leads to a reduction in its level in serum. The correlation between this reduction and the amount of glucose present in urine is so close that 1,5 AG can be used as a sensitive, day-to-day, real-time marker of glycemic control. It provides useful information on current glycemic control and is superior to both HbA1c and fructosamine in detecting near-normoglycemia.

The influence of traditional Chinese herbal drugs on serum 1, 5-anhydroglucitol levels.

The serum concentration of 1,5-anhydroglucitol (1,5-AG), a polyol which originates mainly in the diet, is used in Japan as a new marker for glycemia. To evaluate the potential interference of 1, 5-AG measurements by traditional Chinese medicines (Kampo), we examined the 1,5-AG content in 32 types of concentrated dosage forms of Kampo using high performance liquid chromatography (HPLC). The 32 types of Kampo were the most frequently used in Japan, two of which, Ninjin-yoei-to (7030 microg/g dry weight) and Kami-kihi-to (6700 microg/g dry weight), contained large amounts of 1,5-AG. Six others contained small amounts of 1,5-AG. Both Ninjin-yoei-to and Kami-kihi-to contain the same ingredient, Polygalae radix, which is a crude form of polygalitol (1,5-AG). To confirm the effects of these Kampo medicines on the serum levels of 1,5-AG, we administered Ninjin-yoei-to (7.5 g/day) for 8 weeks to 18 patients with Type 2 diabetes mellitus (Type 2 DM). The serum level of 1,5-AG increased from 9.8+/-8.9 to 28.1+/-17.5 microg/ml by week 8. Hemoglobin A1c (HbA1c) had not changed by week 8. Thus, an abnormal serum 1,5-AG level may be present in patients taking Kampo which contains Polygalae radix.

A pilot clinical trial of a new oral hypoglycemic agent, CS-045, in patients with non-insulin dependent diabetes mellitus.

CS-045, (+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramkethylchroman-2- ylmethoxy)benzyl]-2,4-thiazolidinedione, lowers plasma glucose in several animal models of non-insulin dependent diabetes mellitus (NIDDM) presumably by increasing insulin sensitivity. Little adverse effect was found in a phase 1 study on healthy male subjects. In order to test its efficacy in lowering plasma glucose in NIDDM in man, a pilot multi-center clinical trial of CS-045 was carried out in 146 patients with NIDDM whose glycemic control was inadequate (FPG greater than 140 mg/dl) on diet and/or other oral hypoglycemic agents. CS-045 was given orally in a daily dose of 200 mg or 400 mg for 12 weeks in addition to the previous treatment. The mean fasting plasma glucose (FPG) and fructosamine began to decrease within 2 weeks and the mean HbA1c within 8 weeks. After 12 weeks, the FPG fell from 192 +/- 41 to 155 +/- 45 mg/dl (P less than 0.01), fructosamine from 3.7 +/- 0.6 to 3.3 +/- 0.6 (P less than 0.01), and HbA1c from 8.9 +/- 1.5 to 8.1 +/- 1.5% (P less than 0.01). The drug was effective in 39% of patients in that FPG fell by more than 20% of the initial value. This rate of efficacy was the same when CS-045 was given alone or together with other oral hypoglycemic agents. The drug was more effective in a dosage of 400 mg than with 200 mg (the rate of efficacy 46% vs 25%) and more effective in obese patients than in lean patients (46% vs 25%).(ABSTRACT TRUNCATED AT 250 WORDS)

Non-protein energy overloading induces bacterial translocation during total parenteral nutrition in newborn rabbits.

The effect of energy intake provided by total parenteral nutrition (TPN) on the incidence of bacterial translocation and the relationship between TPN-induced cholestasis and bacterial translocation were investigated in newborn animals. Forty-six Japanese white newborn rabbits were divided into three groups: TPN-H group (high energy TPN; 280 kcal.kg-1.d-1), TPN-L group (low energy TPN; 180 kcal.kg-1.d-1), and a control group (breast fed). On day 8, they were all killed for investigation of the presence of bacterial translocation, for blood chemistry analysis, and for histological examination of the ileum. The incidence of translocation to any of mesenteric lymph nodes and liver and spleen was significantly higher in the TPN-H group (67%) than in both the TPN-L group (13%) and the control group (10%) (P < 0.01). No difference was seen in ileum morphology between the two TPN groups. Although the mean bilirubin level of the TPN-H group tended to be higher than the TPN-L group, whether or not bacterial translocation occurred was not found to be closely related to the degree of TPN-associated cholestasis. In conclusion, parenteral nonprotein energy overloadng increased the incidence of bacterial translocation in the newborn rabbit. However, bacterial translocation did not appear to be associated with the development of TPN-associated cholestasis.

Complications in neonates with short bowel syndrome and long-term parenteral nutrition.

BACKGROUND: Because of advances in parenteral nutrition (PN), the prognosis for patients with short bowel syndrome (SBS) has recently shown great improvement. Even infants with a small bowel measuring only 20 cm either with or without an ileocoecal valve can now survive. However, because of the increased periods of PN, severe complications associated with PN have been observed. PATIENTS AND METHODS: We analyzed 17 patients with SBS treated by long-term PN to investigate the complications of PN, particularly hepatic dysfunction, micronutrient deficiency, and intoxication. RESULTS: Eleven of 17 patients (64.7%) had hepatic dysfunction, mostly cholestasis. The main causes of hepatic dysfunction were loss of enteral feeding and infections. Regarding the complications of the micronutrients, zinc and copper deficiencies have been observed less often because of trace element supplements. However, manganese deposition, especially in the basal ganglia, was recognized in one patient. CONCLUSIONS: We therefore need to pay more attention to these problems when treating this disease in order to improve the overall prognosis significantly.