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Biomedical subjects

T Sanke

Publications and source records attributed to T Sanke.

At least 19 recordsLinked to original sources
PubMed1996

Beta-thalassemia (beta 90 GAG-->TAG): genetic diagnosis by allele-specific polymerase chain reaction and estimation of mutant mRNA expression by reverse transcription polymerase chain reaction.

Genetic diagnosis of a family of beta-thalassemia (beta 90 GAG-->TAG) was carried out by allele-specific polymerase chain reaction (AS-PCR). The proband, her daughter and granddaughter were proved to be heterozygotes of normal and mutant alleles. As some nonsense mutations express a decreased amount of MrNAs, we determined the expression level of the mutant mRNA of beta-thalassemia (beta 90 GAG-->TAG), by application of a combination method of reverse transcription PCR (RT-PCR) and dot-blot hybridization with allele-specific oligonucleotides. The mutant mRNA was not markedly reduced. In conclusion, 1) individuals with the mutant beta-globin gene were diagnosed successfully by AS-PCR, and 2) a significant amount of the mutant beta-globin mRNA was synthesized.

Alleles↗
PubMed1996

Human prohormone convertase 3 gene: exon-intron organization and molecular scanning for mutations in Japanese subjects with NIDDM.

Proinsulin is converted to insulin by the concerted action of two sequence-specific subtilisin-like proteases termed prohormone convertase 2 (PC2) and prohormone convertase 3 (PC3). PC3 is a type I proinsulin-processing enzyme that initiates the sequential processing of proinsulin to insulin by cleaving the proinsulin molecule on the COOH-terminal side of the dibasic peptide, Arg31-Arg32, joining the B-chain and C-peptide. Thus, PC3 plays a key role in regulating insulin biosynthesis. Expressions of insulin and PC3, but not PC2, are coordinately regulated by glucose, consistent with the important role of PC3 in regulating proinsulin processing. NIDDM is associated with increased secretion of proinsulin and proinsulin-like molecules, suggesting that mutations in the PC3 gene may be involved in the development of this disorder. To examine this hypothesis, we have isolated and characterized the human PC3 gene and screened it for mutations in a group of Japanese subjects with NIDDM. The PC3 gene consists of 14 exons spanning more than 35 kb. The exon-intron organization of PC2 and PC3 genes are conserved, consistent with a common evolutionary origin for the prohormone convertase gene family. Single-strand conformational analysis and nucleotide sequencing of the entire coding region of the PC3 gene in 102 Japanese subjects with NIDDM revealed missense mutations in exons 2 (Arg/Gln53) and 14 (Gln/Glu638), neither of which was associated with NIDDM in this population. These data suggest that genetic variation in the PC3 gene is unlikely to be a major contributor to NIDDM susceptibility in Japanese.

Animals↗
PubMed1996

Missense mutation of amylin gene (S20G) in Japanese NIDDM patients.

Many studies suggest that amylin, which is cosecreted with insulin from islet beta-cells, is a biologically active peptide and modulates plasma glucose levels. We therefore scanned the amylin gene for mutations in 294 Japanese NIDDM patients by single-strand conformational polymorphism, and we found a single heterozygous missense mutation (Ser-->Gly at position 20: S20G mutation) in 12 NIDDM patients (frequency 4.1%). None of the 187 nondiabetic subjects or 59 IDDM patients had the mutation. Of 12 patients carrying the mutation, 8 were diagnosed as having NIDDM at a relatively early age (< or = 35 years), and they had severe diabetes and strong family histories of late-onset NIDDM. On the other hand, the remaining four patients were diagnosed as having NIDDM after age 51, and they had mild diabetes without family histories of diabetes. In high-performance liquid chromatography analysis, a small amount (16%) of amylin immunoreactivity appeared in the position corresponding to normal amylin and a much larger amount (84%) appeared in the position corresponding to mutant amylin. These findings suggest that the S20G mutation of the amylin gene may play a partial role in the pathogenesis of early-onset NIDDM in the Japanese population and may also provide an important model to investigate the true physiological action of amylin.

Adult↗
PubMed1995

Association of the prohormone convertase 2 gene (PCSK2) on chromosome 20 with NIDDM in Japanese subjects.

Proinsulin is converted to insulin by the concerted action of two sequence-specific subtilisin-like proteases termed prohormone convertase 2 (PC2) and prohormone convertase 3. PC2 is a type II proinsulin-processing enzyme, and it cleaves the proinsulin molecule on the COOH-terminal side of dibasic peptide, Lys64-Arg65, which joins the C-peptide and the A-chain domains. We have previously cloned and characterized the exon-intron organization of the human PC2 gene (gene symbol PCSK2), localized this gene to human chromosome 20 band p11.2 by fluorescence in situ hybridization, and identified a simple tandem-repeat DNA polymorphism (STRP) in intron 2 of the form (CA)n, suitable for genetic studies. Since non-insulin-dependent diabetes mellitus (NIDDM) is associated with increased secretion of proinsulin and proinsulin-like molecules, we conducted a case-control study to determine whether a genetic variation in PCSK2 might contribute to the development of NIDDM. The study population consisted of 152 Japanese NIDDM subjects and 102 normal healthy nondiabetic control subjects matched for age and body mass index. The subjects were genotyped at the STRP in intron 2, and the results indicated a significant difference (P = 0.004) in the overall allele frequency distribution between the two groups. The A1 allele was found more frequently in NIDDM than in nondiabetic subjects (11 vs. 4%, P = 0.0068). The NIDDM patients were divided into two subgroups according to the presence or absence of the A1 allele.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1994

Simple tandem repeat DNA polymorphism in the human glycogen synthase gene is associated with NIDDM in Japanese subjects.

We investigated the possible association between alleles of a simple tandem repeat DNA polymorphism in the human glycogen synthase gene and non-obese non-insulin-dependent diabetes (NIDDM) in Japanese subjects. Nine alleles (-4G, -3G, -2G, -1G, 0G, 1G, 2G, 3G, and 4G) were identified in the study group of 164 patients with NIDDM and 115 non-diabetic subjects. The overall frequency distribution of the glycogen synthase gene alleles was significantly different between the two groups (p = 0.0316). The 2G allele was found more frequently in patients with NIDDM than in non-diabetic subjects (17.7% vs 8.7%, p = 0.0016). These results suggest that the 2G allele could be a genetic marker of NIDDM in Japanese subjects.

Adult↗
PubMed1994

Nicardipine may impair glucose metabolism in hypertensive diabetic patients.

The respective effects of 6 month's administration of beta-blockers (atenolol, metoprolol, carteolol and arotinolol), calcium-channel blockers (nicardipine, diltiazem) and angiotensin converting enzyme inhibitor (enalapril) on hemoglobin A1c (HbA1c) levels were evaluated in hypertensive patients with non-insulin-dependent diabetes mellitus (NIDDM), using a retrospective method. NIDDM patients with stable HbA1c and body weight were selected for this study. The following results were obtained. (1) The administration of nicardipine or beta-blockers significantly elevated HbA1c levels. (2) The administration of diltiazem or enalapril did not have any influence on HbA1c levels. These findings suggest that not only beta-blocker but nicardipine (dihydropyridine type calcium-channel blocker) may cause deterioration in glucose metabolism in NIDDM patients.

Adult↗
PubMed1994

Abnormal insulinemia.

The recent development of molecular biology enables us to identify three abnormal insulins (insulin Chicago, insulin Los Angeles and insulin Wakayama). In Japan, three pedigrees in which affected individuals secrete [LeuA3] insulin (insulin Wakayama) have been identified. In each family, hyperinsulinemia associated with an abnormally elevated insulin to C-peptide molar ratio was demonstrated to occur in an autosomal dominant pattern of inheritance. In accordance with in vivo observations, semisynthetic [LeuA3] insulin demonstrated reduced in vitro receptor binding and biological activity relative to the human standard. The development of diabetes mellitus in affected family members was not uniform, was influenced by aging, and was different among families. Patients with impaired glucose tolerance demonstrated reduced insulin secretory reserve. Some of these features are thought to resemble the nature of non-insulin dependent diabetes mellitus (NIDDM). Therefore, insulin Wakayama may be a useful model for the study of the development of NIDDM.

Adult↗
PubMed1994

[Review for clinical molecular genetics of mutant insulin].

Three types of structurally abnormal insulin "Insulin Chicago, Los Angeles and Wakayama" has been identified in 6 families by the recent development of molecular biology. It has been clarified that a point mutation in the coding region of each patient's insulin gene allele give rise to a substitution of one amino acid of each insulin, resulting in reduced biological activities of these insulins. These abnormal insulin have slow metabolic clearance rate which cause typical hyperinsulinemia accompanying normal level of plasma C-peptide. In this paper, we review insulin gene mutations and discuss its participation to the pathogenesis of NIDDM.

Diabetes Mellitus, Type 2↗
PubMed1994

[Glycogen synthase gene-glycogen synthase gene in Japanese patients with NIDDM].

As glycogen synthase is a key enzyme of the non-oxidative pathway of glucose metabolism in the skeletal muscle, and reduced activity of this enzyme is related to insulin resistance, it seems likely that this enzyme is a candidate gene for contributing to the pathogenesis of NIDDM. In this paper, we review recent findings of polymorphism of the human glycogen synthase gene, XbaI restriction enzyme length polymorphism and simple tandem repeat DNA polymorphism, and discuss the possible association between the glycogen synthase gene and NIDDM.

Asian People↗
PubMed1994

[Role of IAPP in the pathogenesis and development of NIDDM].

Islet amyloid deposits are the characteristic lesions of the pancreas of the patients with non-insulin-dependent diabetes mellitus (NIDDM). Islet amyloid polypeptide (IAPP or amylin) is a 37 amino acid peptide, which was extracted and characterized from islet amyloid deposits in patients with NIDDM. Recent studies and characterization of IAPP cDNA suggest that IAPP is a normal islet hormone and is co-secreted with insulin from islet beta cells of the pancreas. In this paper, we review recent advance of the research for IAPP including our results, and discuss the role of IAPP in the development of NIDDM, and we propose a new type of diabetes, "amyloid diabetes".

Amino Acid Sequence↗
PubMed1992

Lack of effect of islet amyloid polypeptide on hepatic glucose output in the in situ-perfused rat liver.

Islet amyloid polypeptide (IAPP), a novel peptide isolated from islet amyloid deposits in patients with insulinoma and non-insulin-dependent diabetes mellitus (NIDDM), has been reported to be cosecreted with insulin from pancreatic beta cells and to inhibit glucose uptake and glycogen synthesis in muscle tissue in vitro. We investigated the effects of the synthesized, rat-amidated form of IAPP on hepatic glucose output, and IAPP extraction, using an in situ flow-through perfusion system in rats to elucidate the actions of IAPP on the liver. The IAPP (10(-8) mol/L) alone had no effects on the hepatic glucose release. Infusion of 6 x 10(-11) mol/L glucagon alone resulted in an expected elevation in glucose production (30.0 +/- 1.7 mumol/35 min/g liver). Insulin (3 x 10(-10) mol/L) submaximally decreased the glucagon-stimulated glucose production to 73% (from 30.0 +/- 1.7 to 22.0 +/- 1.4 mumol/35 min/g liver; n = 7, P less than .01). A simultaneous infusion of 10(-8) mol/L IAPP did not influence the glucagon-stimulated glucose production (27.6 +/- 1.2 mumol/35 min/g liver) or the insulin-dependent inhibition of glucagon-stimulated glucose production (22.6 +/- 1.3 mumol/35 min/g liver). IAPP extraction by the liver in a single passage was minimal, in contrast to approximately 50% hepatic insulin extraction. These results indicate that IAPP does not play any important role in modulating glycogen metabolism in the liver.

Amyloid↗
PubMed1992

Restriction fragment length polymorphisms near the islet amyloid polypeptide gene in Japanese subjects.

Two restriction fragment length polymorphisms (RFLPs) near the human islet amyloid polypeptide (IAPP) gene were examined in 50 Japanese patients with non-insulin-independent diabetes mellitus (NIDDM) and 54 non-diabetic controls. RFLPs were identified with the enzymes PvuII (A1 = 21 kb and A2 = 18 kb) and BglII (B1 = 9 kb and B2 = 7 kb). These RFLPs were in complete linkage disequilibrium with A1 which was in disequilibrium with B2, as was A2 with B1. Since these two RFLPs map to different locations in the 5'-flanking region of the IAPP gene, they are most likely due to changes in the sequence of the sites recognized by PvuII and BglII rather than to an insertion/deletion-type DNA polymorphism. There were no differences in the genotypic or allelic frequencies of these RFLPs between Japanese subjects with NIDDM and non-diabetic controls implying that these RFLPs do not play a major role in the development of NIDDM in this population.

Adult↗
PubMed1992

Molecular biology of islet amyloid polypeptide.

We investigated the relationship between non-insulin-dependent diabetes mellitus (NIDDM) and islet amyloid polypeptide (IAPP) gene by restriction fragment length polymorphism (RFLP) and polymerase chain reaction (PCR)-direct sequencing analysis. Endonuclease BglII and/or PvuII RFLP analysis revealed no positive correlation of IAPP gene with NIDDM. In PCR-direct sequencing of 25 NIDDM patients, no nucleotide sequence differences were found. These data do not support the view that IAPP plays an important role in the pathogenesis of NIDDM. cDNAs encoding cat, rat, mouse, guinea pig and degu IAPP precursors were also cloned, and comparison of these predicted amino acid sequences clarified the species difference, especially between amyloid-forming and non-amyloid-forming species. Amino acid residues 25-28 of mature IAPP might be responsible for their amyloidogeneity. The alternative splicing transcripts of guinea pig IAPP gene were identified by using PCR. If these types of transcripts are translated, N-terminal mutated IAPP might be produced and act as an antagonist. The signal peptide cleavage site of rat IAPP precursor was also identified by an in vitro translation and processing system.

Amino Acid Sequence↗
PubMed1992

Islet amyloid polypeptide (IAPP/amylin) causes insulin resistance in perfused rat hindlimb muscle.

It has been reported that islet amyloid polypeptide (IAPP) has insulin antagonistic effects in vivo and in vitro. To determine whether IAPP affects glucose metabolism in skeletal muscle, we performed in situ rat hindlimb perfusion which is a near-physiological system. Forty min after the beginning of insulin infusion at 1000 microU/ml, the synthesized rat amide form of IAPP was infused at 1 nM or 10 nM for 50 min and glucose concentration in the effluent was measured to calculate glucose uptake (GU). The GU did not change during the 1 nM IAPP infusion, but significantly decreased during 10 nM IAPP infusion (554 +/- 24 to 445 +/- 29 nmol/g/min, P less than 0.01). Rat calcitonin gene-related peptide (CGRP), which has sequence homology with IAPP and has been reported to inhibit insulin action, was also administered. Similar to the effect of IAPP, the GU did not change during 1 nM CGRP infusion but significantly decreased during 10 nM CGRP infusion (507 +/- 7 to 323 +/- 15 nmol/g/min, P less than 0.01). In the experiments without insulin infusion, the GU was not changed even by 10 nM IAPP infusion. Therefore, IAPP directly reduced only the insulin-mediated GU in the skeletal muscle, and this effect of IAPP occurred at the same dose as that of CGRP. These data suggest that both IAPP and CGRP may cause insulin resistance in skeletal muscle not through a CGRP receptor but a yet unknown receptor, which has similar binding affinity for both IAPP and CGRP.

Amyloid↗
PubMed1992

Islet amyloid polypeptide (IAPP) secretion from islet cells and its plasma concentration in patients with non-insulin-dependent diabetes mellitus.

Islet amyloid polypeptide (IAPP/Amylin) is a novel peptide which was extracted from islet amyloid deposits in patients with non-insulin-dependent diabetes mellitus (NIDDM). However, its pattern of secretions and plasma concentrations under various conditions has not yet been made clear enough. In this study, we examined IAPP secretion from islet beta-cells in vitro using cultured islet cells of neonatal rat pancreas and plasma IAPP responses under various conditions in vivo in normal control subjects and patients with glucose intolerance. Our data revealed that (1) IAPP is co-secreted with insulin from islet cells of the rat pancreas by glucose and non-glucose stimuli; (2) fasting plasma IAPP levels in normal control subjects are 24.9 +/- 2.0 pg/ml and the molar ratio of IAPP/insulin is approximately 1/7; (3) fasting IAPP levels are high in obese patients and low in insulin-dependent diabetic patients, and the molar ratio of IAPP/C-peptide in NIDDM patients is lower than that in normal control subjects, suggesting the basal hyposecretion of IAPP relative to insulin in NIDDM; and (4) the obese patients who had a hyperresponsiveness of insulin relative to C-peptide had the hyperresponsiveness of IAPP relative to C-peptide during an oral glucose load, suggesting that IAPP may have some physiological effect in glucose metabolism.

Adult↗
PubMed1991

Plasma islet amyloid polypeptide (Amylin) levels and their responses to oral glucose in type 2 (non-insulin-dependent) diabetic patients.

Fasting plasma islet amyloid polypeptide concentrations and their responses to an oral glucose load were determined in non-diabetic control subjects and patients with abnormal glucose tolerance in relation to the responses of insulin or C-peptide. Plasma islet amyloid polypeptide was measured by radioimmunoassay. In the non-diabetic control subjects, fasting plasma islet amyloid polypeptide was 6.4 +/- 0.5 fmol/ml (mean +/- SEM) and was about 1/7 less in molar basis than in insulin. The fasting islet amyloid polypeptide level rose in obese patients and fell in patients with Type 1 (insulin-dependent) diabetes mellitus. In non-obese patients with impaired glucose tolerance and Type 2 (non-insulin-dependent) diabetic patients without insulin therapy, the level was equal to that of the control subjects, but a low concentration of islet amyloid polypeptide relative to insulin or C-peptide was observed in the non-obese Type 2 diabetic group. The patterns of plasma islet amyloid polypeptide responses after oral glucose were similar to those of insulin or C-peptide. However, compared to non-obese patients, a hyper-response of islet amyloid polypeptide relative to C-peptide was noted in obese patients who had a hyper-response of insulin relative to C-peptide. This study suggests that basal hypo-secretion of islet amyloid polypeptide relative to insulin exists in non-obese Type 2 diabetes and that circulating islet amyloid polypeptide may act physiologically with insulin to modulate the glucose metabolism.

Adult↗
PubMed1991

[A case of so-called neoplastic angioendotheliosis with fever of unknown origin and temporary loss of consciousness].

A 65-year-old man was hospitalized with prolonged fever. The erythrocyte sedimentation rate was 62 mm/hour and the c-reactive protein was 5+. Serum lactic dehydrogenase was 1005 IU with elevation of isozyme types II and III. A computerized tomography scan of the abdomen showed large, bilateral adrenal masses. An aspirated specimen of the bone marrow revealed some clustered atypical cells. These findings suggested the patient had metastatic carcinoma, but the primary lesion could not be found. The patient had an episode of transient unconsciousness in mid course and died of bleeding from the gastrointestinal tract. A postmortem examination was performed. Microscopic examination showed an accumulation of neoplastic cells in the vascular system throughout the body and their extravascular proliferation in several organs. Immunohistochemical studies were performed on paraffin-embedded fixed tissues. The neoplastic cells were positive with the monoclonal antibodies LCA, LN 1, LN 2 and N 26 but did not show positive staining for factor VIII-related antigen, a marker for endothelial cells. These studies defined the neoplastic cells as being of a germinal-center B lymphocyte origin. On the basis of the above-mentioned results, we suggest that this case may be diagnosed as angiotrophic lymphoma.

Aged↗