PubMed Health⌕ Search

Biomedical subjects

T Watarai

Publications and source records attributed to T Watarai.

At least 19 recordsLinked to original sources

Evaluation of gut motility in type II diabetes by the radiopaque marker method.

BACKGROUND: The clinical usefulness of the radiopaque marker method for detecting diabetic gastrointestinal motility disturbances, was evaluated by examining 21 type II diabetes subjects who did not have any neuropathic symptoms. METHODS: After administration of a Sitzmark capsule, markers were located using plain abdominal radiographs, and the transit time of the markers through seven areas of digestive tract was calculated by Arhan's methods. The plasma concentration of acetaminophen at 45 min after oral administration was measured to evaluate gastric emptying time. The coefficient of variation of R-R intervals on the electrocardiograms (CV(R-R)) was measured to evaluate parasympathetic autonomic function. RESULTS: In the diabetics, the average (+/- SD) transit time through upper digestive tracts was slightly but not significantly elongated compared with control subjects (14.4 +/- 8.3 vs 9.9 +/- 6.1 h). Significant elongation was observed in transit time through the lower digestive tracts or the whole gut (44.6 +/- 20.9 and 57.9 +/- 22.3 h, respectively) compared with control subjects (23.3 +/- 8.5 and 33.2 +/- 11.0 h). The transit time of the markers from stomach to small intestine was highly correlated (r = 0.693) with plasma concentration of acetaminophen. The transit time through either the whole colon (r = 0.564) or the whole gut (r = 0.630) was highly correlated with CV(R-R). CONCLUSIONS: These findings suggest that the radiopaque marker method is a useful tool for detecting the sections of the digestive tract responsible for gut motility disturbances. In type II diabetics with no neuropathic symptoms, the lower digestive tracts may deteriorate prior to the impairment of upper digestive tracts.

Acetaminophen↗

Insulin resistance contributes to carotid arterial wall thickness in patients with non-insulin-dependent-diabetes mellitus.

The aim of this study was to clarify whether insulin resistance contributes to atherosclerosis in patients with non-insulin-dependent diabetes mellitus (NIDDM). Fifty-three NIDDM patients (36 males and 17 females, 53+/-10 years old (mean+/-SD)) were studied. As an index of atherosclerosis, we measured the average thickness (IMT) as well as basal thickness excluding the maximum thickness and the height of the maximum thickness of the carotid artery wall. Euglycemic hyperinsulinemic glucose clamp was conducted for 90 min to evaluate average glucose infusion rate (GIR) as an index of insulin sensitivity in the peripheral tissues. For another 180 min after intake of oral glucose load with 0.3 g/kg, the euglycemic hyperinsulinemic clamp was continued to measure ratio of splanchnic glucose uptake (SGU) as an index of insulin sensitivity of the liver. The patients were separated into three activity groups according to the grade of their leisure-time physical activity. GIR (r = -0.32, p < 0.05) but not SGU (r=0.139) showed a significant inverse relationship with IMT. Multivariant regression analysis indicated that age and total cholesterol remain as independent risk factors for basal thickness and GIR as only independent risk factor for the height of the maximum thickness. Paralleling the degrees of habitual exercise (low, moderate, and high active group), GIR was higher (6.19+/-1.02, 6.38+/-1.38, 7.44+/-1.80, respectively) and IMT was lower (1.34+/-0.33 mm, 1.20+/-0.31 mm, and 1.12+/-0.29 mm, respectively) in male NIDDM as well as in female NIDDM. These data suggest that insulin resistance in the peripheral tissues but not the splanchnic tissues may independently contribute to carotid arterial wall thickness and especially to plaque lesion, and that habitual exercise might reduce insulin resistance leading to attenuation of atherosclerosis.

Aged↗

Sensitive, selective gas chromatographic-mass spectrometric analysis with trifluoroacetyl derivatives and a stable isotope for studying tissue sorbitol-producing activity.

One of the major mechanisms involved in diabetic microangiopathy is considered to be an altered polyol pathway. However, clarifying the pathophysiology is difficult due to the lack of a sensitive method for measuring the reduction of glucose to sorbitol in tissue. Here we report a sensitive and selective method for polyol measurement using trifluoroacetyl (TFA) derivatives of polyols and stable isotope-labeled D-sorbitol (U-[13C]sorbitol, 13C6H14O6, 98.7%) as an internal standard. Gas chromatography-mass spectrometry (GC-MS) using an SE-30 capillary column gave elution of TFA derivatives of sugars, polyols and U-[13C]sorbitol within 8 min, with clear separation of sorbitol. In the calibration study, the coefficients of correlation between the amount of sorbitol added and that determined in standard solutions containing 0.1-8.0 nmol sorbitol, erythrocyte mixture and liver cytosol mixture were r = 0.999, r = 0.997 and r = 0.997, respectively. The precision of the GC-MS measurement of standard solution was C.V. = 4.3%. Because glucose is used as a substrate, the method can clarify the polyol pathway under physiological conditions. With this method, Km and Vmax values of the reductase in erythrocytes were 115 +/- 19 mmol/l and 4.42 +/- nmol/min/g of hemoglobin. In human liver, on the other hand, they were 755 +/- 132 mmol/l and 0.773 +/- 0.090 nmol/min/mg of protein, respectively. This difference of Km values suggested that aldehyde reductase rather than aldose reductase is mainly responsible for reducing glucose to sorbitol in the liver. In conclusion, this newly developed method offers a highly sensitive and selective procedure for measuring low concentrations of sorbitol in various tissues and cells and should enable clarification of the kinetics of glucose reduction to sorbitol, which in turn can be used to evaluate the role of an altered polyol pathway in the pathophysiology of diabetic microangiopathy.

Adolescent↗

Cloning and sequencing of the gene encoding tannase and a structural study of the tannase subunit from Aspergillus oryzae.

We cloned the Aspergillus oryzae tannase gene using three oligodeoxyribonucleotide (oligo) probes synthesized according to the tannase N-terminal and an internal amino acid (aa) sequence. The nucleotide (nt) sequence of the tannase gene was determined and compared with that of a tannase DNA complementary to RNA (cDNA) by means of reverse transcriptase PCR. The results indicated that there was no intron in the tannase gene and that it coded for 588 aa with a molecular weight of about 64,000. The tannase low-producing strain A. oryzae AO1 was transformed with the plasmid pT1 which contained the tannase gene, and tannase activities of the transformants increased in proportion to the number of copies. Tannase consisted of two kinds of subunits, linked by a disulfide bond(s) with molecular weights of about 30,000 and 33,000, respectively. We purified these subunits and determined their N-terminal aa sequences. The large and small subunits of tannase were encoded by the first and second halves, respectively. Judging from the above results, the tannase gene product is translated as a single polypeptide that is cleaved by post-translational modification into two tannase subunits linked by a disulfide bond(s). We concluded that native tannase consisted of four pairs of the two subunits, forming a hetero-octamer with a molecular weight of about 300,000.

Amino Acid Sequence↗

Recurrent Cushing's disease associated with nephrotic syndrome.

A case of recurrent Cushing's disease with nephrotic syndrome due to membranoproliferative glomerulonephritis (MPGN) is presented. Functional pituitary adenoma recurred 6 years after transsphenoidal pituitary adenomectomy. Due to infiltration into the surrounding tissues, transcranial surgery was performed. However, this failed to induce a remission and thus gamma knife therapy was applied. Histopathological evaluation revealed that the glomerular lesions had progressed to a rather advanced stage of MPGN. Although this association could be coincidental, the recurrence of pituitary macroadenoma might be induced by the cessation of steroid treatment for the nephrotic syndrome.

Adult↗

Platelet activation in diabetic patients with asymptomatic atherosclerosis.

We studied 27 non-insulin-dependent diabetics without apparent atherosclerosis (AS) to investigate whether abnormal platelet function is related to asymptomatic atherosclerosis in diabetes mellitus. The degree of AS was quantitatively evaluated by determining the intimal plus medial thickness (IMT) of the carotid artery wall with ultrasound high-resolution B-mode imaging. Based on our previous finding that the upper threshold of the IMT was 1.1 mm in healthy subjects, the patients were divided into the AS-positive group with the IMT > 1.1 mm, (n = 17) and the AS-negative group with the IMT < 1.1 mm (n = 10). Among five variables measured as the factors concerned with thrombogenesis, only plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4) were significantly higher in the AS-positive group than in the AS-negative group. Chronic administration of pentoxifylline (300 mg/day) significantly reduced the abnormally high plasma levels of beta-TG and PF4 in 7 patients of the AS-positive group to normal levels, without lowering the normal plasma beta-TG and PF4 levels in the remaining 10 patients. Pentoxifylline treatment did not affect the plasma levels of the 3 other variables, von Willebrand factor, 6-keto prostaglandin F1 alpha and thromboxane B2. This study suggests that the progress of atherosclerosis in diabetes mellitus is associated with in vivo platelet activation and platelet activation does not occur in diabetics without carotid atherosclerosis. Pentoxifylline may impede the vicious cycle in which atherosclerosis is accelerated by platelet activation.

Aged↗

Effect of strict metabolic control on glucose handling by the liver and peripheral tissues in non-insulin-dependent diabetes mellitus.

To examine the effect of strict glycemic control on the insulin resistance of non-insulin-dependent diabetes mellitus (NIDDM), we applied euglycemic hyperinsulinemic clamp combined with an oral glucose load (OGL) to nine non-obese subjects with NIDDM and quantitated insulin-mediated glucose uptake by the liver (HGU) and peripheral tissues (PGU) simultaneously before and after 3 to 4 weeks of intimate glycemic control by preprandial regular insulin injections 3 times a day. The glucose infusion rate (GIR) required to maintain euglycemia during the clamp before OGL was considered as PGU. After OGL, the fraction of ingested glucose that is not extracted by the liver enters the systemic circulation and reduces the GIR required for the clamp. HGU was calculated from the difference between the amount of OGL and the cumulative decrements in GIR after OGL and was expressed as the ratio to the amount of OGL (%). Three to 4 weeks after initiation of strict metabolic control, FPG and HbA1c levels significantly improved (9.1 +/- 0.5 vs. 6.4 +/- 0.4 mmol/l, and 11.2 +/- 0.8 vs. 8.3 +/- 0.3%, P < 0.05). HGU significantly increased to 33.1 +/- 9.5 from 14.5 +/- 4.8%, while PGU did not change (38.2 +/- 5.2 vs. 37.4 +/- 3.9 mumol/kg.min). These data suggest that short-term strict metabolic control ameliorates insulin resistance in NIDDM mainly at the hepatic level.

Adult↗

Comparison of the continuously calculated fractional splanchnic extraction of insulin with its fractional disappearance using a new double-tracer technique.

These studies were designed to calculate the fractional disappearance rate (FDR) and splanchnic extraction of insulin in response to an exogenous (intraperitoneal) input of insulin. A double-tracer technique using insulin tritiated on both the A1 and B1 positions was introduced for the measurement of hepatic extraction. The A1 tracer, not previously characterized in vivo, was compared in terms of its kinetics with H3-B1-insulin and unlabeled insulin. The metabolic clearance rates (MCR) of the three insulins were identical, as were the decay curves of the two tracers. To measure splanchnic insulin extraction, one tracer was infused systemically to evaluate the FDR of insulin, and the second was infused into the splanchnic circulation (superior mesenteric artery) and its peripheral appearance was calculated. Splanchnic extraction was determined from the difference between this rate of appearance and the rate of infusion of the mesenteric tracer. After intraperitoneal insulin injection, insulin levels increased to peaks of 549 +/- 93 microU/mL (portal vein) and 473 +/- 99 microU/mL (inferior vena cava) and decreased to basal levels over 3 hours. The FDR decreased from 0.295 +/- 0.051 min-1 to 0.125 +/- 0.026 min-1, and splanchnic extraction decreased from 0.534 +/- 0.06 to 0.232 +/- 0.088. The latter returned to near-basal values more rapidly than did the FDR. In conclusion, the kinetics of insulin both in and out of the steady state have been shown to be nonlinear through physiological insulin concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effects of the contents of dietary crude protein on growth rate and NK activity.

The relationship between body weight gain and food intake was examined using 3 strains of mice, C3H/He, C57BL/6 and A/J mice, that were fed 4 kinds of diets differing in crude protein contents. Body weight gain of the mice fed the diet containing 3% protein was extremely small, while that of the mice fed the diet containing 40% protein was smaller than that of the mice fed the diet containing 10% or 20% protein. Mice were shown to possess a characteristic ability to intake an almost constant amount of calories irrespective of crude protein contents in diets, with some exceptions. These experimental results indicate that crude protein intake plays an important role for body weight gain. It was also assumed that energy consumption in C57BL/6 mice fed the 40% protein diet was accelerated because of excessive protein intake. Normal NK activity and antibody responses to SRBC were maintained at the age of 12 weeks in all the strains of mice fed the different diets.

Animal Nutritional Physiological Phenomena↗

Inhibitory effect of methylguanidine on insulin binding to its receptor. Mechanism underlying insulin resistance in uremia.

To elucidate the mechanism responsible for the decreased insulin binding to erythrocytes in uremic patients, the effects of incubation with sera obtained from uremic patients or with methylguanidine, respectively, on insulin binding were examined. Insulin binding to erythrocytes from uremic patients was lower than that from normal subjects (3.1 +/- 0.19% vs 6.6 +/- 0.33%, Mean +/- SEM, P less than .005), being due mainly to decreased binding affinity (58% of control). Incubation of erythrocytes with 1:5 diluted sera of uremic patients resulted in decreased insulin binding (65 +/- 5% of control) and this decrease was restored to the level of 78 +/- 3% of the controls after incubation with buffer for 12 h. Methylguanidine inhibited insulin binding to erythrocytes in a dose-dependent manner. Post-dialyzed serum with 100 ng/ml of methylguanidine (as seen in pre-dialyzed uremic patients) inhibited insulin binding to erythrocytes as much as pre-dialyzed serum (54.3 +/- 3% vs 47 +/- 1% of control). Incubation of IM-9 lymphocytes with 100 ng/ml of methylguanidine did not alter the insulin receptor mRNA level. These results suggest that methylguanidine inhibits insulin binding to its receptor, resulting in decreased insulin binding to erythrocytes.

Erythrocytes↗

Two patients with insulin resistance due to decreased levels of insulin-receptor mRNA.

Mutations have been identified in the insulin-receptor gene in insulin-resistant patients. We studied two patients with acanthosis nigricans and insulin resistance caused by a decrease in the number of cell surface insulin receptors. Patient 1 was an 11-yr-old boy with a fasting insulin level of 2130 pM; patient 2 was a 14-yr-old girl with hyperandrogenism and a fasting insulin level of 580-740 pM. Based on Southern-blotting studies, the structure of both alleles of the insulin-receptor gene in both patients appeared to be grossly normal. There was no evidence of insertions, deletions, or major rearrangements. Moreover, the nucleotide sequences of all 22 exons of the gene were normal in both patients. Thus, the predicted amino acid sequences of both patients' insulin receptors were normal. In Epstein-Barr virus-transformed lymphoblasts from patient 1, insulin-receptor mRNA levels were so low they could not be detected with an RNase A protection assay, whereas mRNA levels from patient 2 were in the lower half of the normal range. By use of a more sensitive assay based on the polymerase chain reaction, insulin-receptor mRNA could be detected in Epstein-Barr virus-transformed lymphoblasts from both patients. Moreover, because of the existence of silent polymorphisms in the nucleotide sequences, it was possible to differentiate the two alleles of the insulin-receptor gene in both patients. In patient 2, the two alleles were expressed asymmetrically, with 90% of the mRNA molecules having been transcribed from one allele but only 10% transcribed from the second allele. This suggests that there is an unidentified mutation in the underexpressed allele that acts in a cis-dominant fashion to decrease insulin-receptor mRNA levels. However, in patient 1, both alleles were expressed symmetrically in similarly low levels. Although not proven, it seems likely that the mutations that decrease insulin-receptor mRNA levels in patient 1 also map to the insulin-receptor locus.

Adolescent↗

Dephosphorylation of the insulin receptor partially restores the decreased autophosphorylation in streptozotocin induced diabetic rats.

The insulin resistance seen in diabetes mellitus has been attributed partly to impaired autophosphorylation of the insulin receptor. It has been suggested that the phosphorylation of serine and/or threonine residues of the insulin receptor may reduce tyrosine autophosphorylation in streptozotocin-induced diabetic rats (STZ-D rats). To elucidate the mechanisms of decreased autophosphorylation of the insulin receptor in diabetic rats, we have investigated the effect of dephosphorylation of the insulin receptor by alkaline phosphatase on the insulin- and protein kinase-stimulating incorporation of 32P into the receptor of the liver from STZ-D rats. Both basal and insulin-stimulated autophosphorylations of the insulin receptor from STZ-D rats were significantly impaired to those from normal rats. Dephosphorylation of the insulin receptor by alkaline phosphatase resulted in an increase in insulin-stimulated autophosphorylation of the insulin receptor from STZ-D rats (43 +/- 13% to 66 +/- 14%, P less than 0.05), but not from normal rats (100% to 109 +/- 12%, NS). Although maximal autophosphorylation of the dephosphorylated insulin receptor was still lower in STZ-D rats than in normal rats, the increase in insulin-stimulated autophosphorylation of the insulin receptor from STZ-D rats by dephosphorylation was higher than that from normal (159.2 +/- 27.2% vs 108.0 +/- 12.4%, p less than 0.01), supporting the idea that the residues of the insulin receptor of STZ-D rats was highly phosphorylated.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗

5'-flanking DNA of the human insulin receptor gene and long terminal repeat of mouse mammary tumour virus bind to the same nuclear protein(s).

The interaction of nuclear protein extracted from rat liver and 5'-flanking DNA of the human insulin receptor gene was investigated with the aid of gel mobility shift analysis. When 5'-flanking DNA (-1255/-1206 or -385/-345 base pairs) was incubated with nuclear protein, two or three 32P-DNA species (protein binding DNA fragment(s) and free DNA fragment) were detected. These bands did not disappear in spite of increasing amounts of synthetic poly(dI-dC), showing that nuclear protein binds specifically to 5'-flanking DNA of the insulin receptor gene. Increasing amounts of long terminal repeat of mouse mammary tumour virus resulted in a reciprocal decrease in nuclear protein binding to 5'-flanking DNA of insulin receptor gene. These results suggest that 5'-flanking DNA of insulin receptor gene binds to the same nuclear protein to which long terminal repeat of mouse mammary tumour binds.

Animals↗