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Biomedical subjects

H Sakura

Publications and source records attributed to H Sakura.

At least 55 records · Page 3Linked to original sources
PubMed1991

The neuropeptide, head activator, in human placenta and serum from pregnant women.

The hydra neuropeptide, head activator, was detected in human placenta using radioimmunoassay. The placenta contained 11-68 fmol/g wet weight of head activator. The slope of the inhibition curve by placental extract in radioimmunoassay was identical to that of synthetic head activator. The molecular weight of the major immunoreactive head activator in placental extract corresponded to the synthetic head activator after Bio-Gel P-2 column chromatography. The peak of immunoreactive head activator in the extract emerged at the same retention time as that of the synthetic head activator on reversed-phase high-performance liquid chromatography. Head activator was localized histologically in trophoblasts of placenta by peroxidase-antiperoxidase staining techniques. The head activator staining was inhibited by the excessive synthetic head activator. The serum head activator level during pregnancy ranged from 9 to 31 pmol/l. A positive linear correlation was found between serum head activator content and gestational weeks.

Amino Acid Sequence↗
PubMed1990

Insulin enhancer binding protein has helix-loop-helix structure.

Insulin gene expression is restricted to pancreatic B cells and the 5' flanking region is responsible for the tissue specificity. The GCCATCTG motif in this region of the rat insulin 1 gene functions as an enhancer for insulin transcription. A cDNA coding for a GCCATCTG motif-binding protein (IEBP1) was isolated from a rat pancreatic B cell tumor lambda gt11 library. The IEBP1 protein was found to be the rat counterpart of the immunoglobulin (Ig) enhancer binding protein E12/47 having a helix-loop-helix domain. This result indicates that the Ig gene and insulin gene employ the same (or a similar) binding protein as a part of their transcriptional apparatus.

Amino Acid Sequence↗
PubMed1989

Putative metal finger structure of the human immunodeficiency virus type 1 enhancer binding protein HIV-EP1.

The region containing two copies of the sequence GGGACTTTCC in the human immunodeficiency virus type 1 (HIV-1) long terminal repeat, that is an NF-kappa B binding site, functions as an enhancer element for HIV transcriptional regulation. By a Southwestern method we have isolated a cDNA encoding the HIV-1 enhancer binding protein (HIV-EP1) from a human B-cell lambda gt11 library. DNase I footprinting analysis using the HIV-EP1 protein expressed in Escherichia coli showed that HIV-EP1 specifically bound to the HIV-1 enhancer. HIV-EP1 protein contains a domain with two tandem "zinc finger" sequences initially described in the Xenopus transcription factor IIIA. This represents the first demonstration of the structural feature of the protein that binds to the HIV-1 enhancer.

Amino Acid Sequence↗
PubMed1989

Leucine zipper structure of the protein CRE-BP1 binding to the cyclic AMP response element in brain.

By screening a lambda gt11 library with the multimerized sequence of the cAMP response element (CRE), we isolated human clones encoding the CRE binding protein, CRE-BP1, from a human brain cDNA library. CRE-BP1 expressed in Escherichia coli bound not only to the CRE element of the somatostatin and fibronectin genes, but also to the CRE element of the adenovirus E4 gene, suggesting that the protein was not distinguishable from the adenovirus transcription factor, ATF. The human CRE-BP1 clone encoded a 54.5 kd protein similar at its carboxy terminus to the leucine zipper motifs found in other enhancer binding proteins such as C/EBP and c-jun/AP-1. CRE-BP1 mRNA was expressed in all of the cells examined and was abundant in brain. The structure of CRE-BP1 and its recognition elements suggest that cellular response to extracellular stimuli is controlled by a family of transcription factors that bind to related cis-active elements and that contain several highly conserved domains.

Activating Transcription Factor 2↗
PubMed1989

Occurrence of an anti-peplomycin IgE antibody cross-reacting with bleomycin in a patient with cervical uterine cancer.

An allergic reaction to peplomycin was observed in a patient with cervical uterine cancer who had previously been treated with peplomycin. A positive Prausnitz-Küstner test and its elimination after heat treatment of the serum showed the production of anti-peplomycin IgE antibody. Peplomycin was coupled to a paper disc and a sensitive radioallergosorbent test for peplomycin was developed to quantitate the antibody. Patient serum IgE and IgG were purified by DE52 column chromatography; the IgE fraction contained binding activity to peplomycin. A competition test revealed that the antibody bound to both peplomycin and bleomycin. DNA, RNA, and mononucleotides had no effect on antibody binding, but the antibody inhibited peplomycin's activity.

Aged↗
PubMed1989

Effect of cigarette smoking on the gastric mucosal blood volume index and hemoglobin oxygenation in man.

The acute effect of cigarette smoking on the gastric mucosal blood volume index and the oxygen saturation of hemoglobin (SO2) in the gastric mucosa was investigated in 12 young male volunteers using reflectance spectrophotometry during endoscopy. Six of these volunteers were habitual smokers who had smoked more than 20 cigarettes a day for more than five years. The others were non-habitual smokers who smoked less than 20 cigarettes a year. The indices of mucosal blood volume and the mucosal blood SO2 level were calculated from the spectra obtained at the lesser curvature of the lower corpus of the stomach before and after cigarette smoking. The indices of mucosal blood volume and mucosal blood SO2 decreased significantly after one to three puffs of cigarette smoking in all subjects as compared to the value before smoking, and the degree of decrease in these parameters was significantly greater in the non-habitual smokers than in the habitual smokers. These results suggest that only one to three puffs of cigarette smoking causes a decrease in the mucosal blood volume and the mucosal blood SO2 which might be related to weakening of mucosal defensive factors.

Adult↗
PubMed1989

Delineation of three functional domains of the transcriptional activator encoded by the c-myb protooncogene.

The c-myb protooncogene encodes a sequence-specific DNA-binding protein (c-Myb) that induces transcriptional activation or repression. We have identified three functional domains of the mouse c-Myb protein that are responsible for DNA binding, transcriptional activation, and negative regulation, respectively. In addition to the DNA-binding domain, which is located near the N terminus, an adjacent region (the transcriptional activation domain) containing about 80 amino acids was found to be essential for transcriptional activation. Deletion of a region spanning about 175 amino acids of the C-proximal portion increased transcriptional activation markedly, revealing that this domain normally represses activation. Differences between the transcriptional activation and repression functions of c-Myb and v-Myb are discussed in the light of these functional domains. Our results suggest that transcriptional activation may be involved in transformation by myb gene products.

Actins↗
PubMed1989

Changes in the intracellular calcium ion concentration in the gastric mucosa in a rat ischemia-reperfusion model.

To investigate the role of the intracellular calcium ion in the development of acute gastric mucosal lesions, phosphorylase a activity was measured as an index of the intracellular calcium ion concentration ([Ca2+]i), using Lowry's method, in the rat ischemia-reperfusion model. [Ca2+]i increased significantly at the end of the ischemic state without acute mucosal lesions (AGML). After reinfusion, [Ca2+]i showed a slight increase and AGML developed. Continual intravenous infusion of the calcium channel blocker, diltiazem (1 mg/kg/hr), inhibited the increase in [Ca2+]i in the ischemic state and reduced the development of AGML after reinfusion. These results suggest that the increase in [Ca2+]i in the ischemic state plays an important role in the development of AGML.

Animals↗
PubMed1989

The effect of DQ-2511, a newly synthesized anti-ulcer drug, on the gastric mucosal hemodynamics and ulceration in rats.

DQ-2511, which is a dopamine derivative, is a newly synthesized anti-ulcer drug. Pretreatment with DW-2511 in the hemorrhagic shock-reperfusion model in rats significantly prevented the decreases of gastric mucosal blood volume, mucosal blood oxygenation index and the ulcer formation. The decrease in gastric mucosal blood oxygenation index in hemorrhagic shock state has a linear correlation with the size of the mucosal ulcers both in DQ-2511 and control groups. The results suggested that DQ-2511 exerts its anti-ulcer activity by improving mucosal hemodynamics in hemorrhagic shock-reperfusion rat model.

Animals↗
PubMed1989

[Roles of intrinsic prostaglandins and leukotrienes in gastric mucosal damage].

While gastric mucosa contains prostaglandins and leukotrienes, the roles of these substances in the gastric mucosal protection and damage are not clarified. Using AA-861, a specific 5-lipoxygenase inhibitor, and indomethacin, a cyclooxygenase inhibitor, we investigated the roles of intrinsic prostaglandins and leukotrienes in the gastric circulatory change and the development of gastric lesion induced by ethanol. Rats were fasted for 48 hours and allowed free access to water. After light ether anesthesia, rats were orally given AA-861 (gift from Takeda Chem. Industry; 2.5, 10, 40 or 640 mg/kg), indomethacin (20 mg/kg), and the both or AA-861 (40 mg/kg) and indomethacin (20 mg/kg). Thirty min after the treatment, 2 ml of ethanol (30, 40, 70, 99.5%) was orally administered. Sixty min later, the rats were killed to measure the area of mucosal lesions. The gastric mucosa was damaged by ethanol (greater than or equal to 40%) in a dose-dependent manner. The treatment with AA-861 prohibited the gastric mucosal damage. However, the treatment with indomethacin did not show a significant influence to the mucosal damage. Combined treatment of AA-861 and indomethacin yielded no significant difference from that of single treatment with AA-861 in acute gastric mucosal ulceration. The mucosal blood flow velocity was monitored by laser doppler velocimetry before and after the ethanol administration in the groups treated with vehicle, AA-861 or indomethacin. The blood flow velocity decreased after the administration of 40% ethanol in the group treated with indomethacin, and in a group treated with vehicle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Two human genes isolated by a novel method encode DNA-binding proteins containing a common region of homology.

Two cDNAs encoding new DNA-binding proteins (Dbps) have been cloned using a human placenta lambda gt11 recombinant cDNA library and DNA fragments as probes. Hybrid proteins expressed by the lambda gt11 cDNA library were blotted onto nitrocellulose filters, and incubated with three different radio-labeled DNA probes containing the human epidermal growth factor (EGF) receptor enhancer or the human c-erbB-2 promoter. Two kinds of clones, named dbpA and dbpB, showed high affinities for the DNA probes. The comparison of the nucleotide and the deduced amino acid (aa) sequences between these two cDNAs indicated that 100 of 109 aa located in the central region of these two Dbps were identical. The dbpA and dbpB-coded proteins also had an affinity for other cDNA probes such as the human c-ski gene, but not for poly(dI-dC).poly(dI-dC), suggesting that the sequence(s) recognized by the dbpA and dbpB-coded proteins may occur frequently, or that these proteins bind to DNA non-specifically in a different manner from that of histones. A simple method, described in this paper, can be used to isolate cDNA clones encoding Dbps. Strategies used for the detection of sequence-specific and non-specific Dbps are discussed.

Amino Acid Sequence↗
PubMed1988

Glucocorticoids increase insulin binding and the amount of insulin-receptor mRNA in human cultured lymphocytes.

The effect of steroid hormones on insulin binding and the amount of insulin-receptor mRNA was examined in IM-9 lymphocytes. Cortisol and cortexolone, but not oestrogen, increased both the binding of insulin and the amount of insulin-receptor mRNA in a time- and dose-dependent manner. Cortisol was most potent, and induced a 2-fold increase in insulin binding and a 4-fold increase in mRNA. The elevation in binding was due to an increased number of insulin receptors at the cell surface. The increase in mRNA involved all four of the insulin-receptor mRNAs and could not be inhibited by cycloheximide. The cortisol-induced increase in mRNA was associated with a 3-4-fold increase in the synthesis of pro-receptor. The relative potency of the three steroids indicated that these effects were mediated by an interaction with the glucocorticoid receptor. The results of this study suggest that cortisol can increase the number of insulin receptors at the cell surface by increasing the amounts of insulin-receptor mRNA and the synthesis de novo of insulin receptors.

17-Hydroxycorticosteroids↗
PubMed1987

Reduced urinary insulin clearance in patient with abnormal insulinemia.

We recently reported a new case of abnormal insulinemia with LeuA3 insulin. Herein, we measured urinary insulin clearance during oral glucose tolerance tests in proband with abnormal insulinemia (44-yr-old female), three affected family members, two unaffected family members, two other hyperinsulinemic patients with obesity, five non-insulin-dependent diabetic patients, and five normal control subjects. Urinary insulin-to-creatinine clearance ratio in the proband and her affected family members was 0.22 X 10(-3) +/- 0.07 (mean +/- SD, n = 4) and was markedly reduced compared with those of other groups: 1.73 X 10(-3) in two unaffected family members, 2.77 X 10(-3) in two other hyperinsulinemic patients with obesity, 2.99 X 10(-3) +/- 1.48 in five non-insulin-dependent diabetic patients, and 2.54 X 10(-3) +/- 0.67 in five normal control subjects. In contrast, urinary C-peptide clearance in these groups was not significantly different from controls. Binding of immunopurified insulins extracted from urine of the patients with abnormal insulinemia to guinea pig kidney membrane was slightly decreased (71% of standard insulin), in contrast with the observation that serum insulin of the proband had much less receptor-binding activity. Reverse-phase HPLC analysis of the immunopurified insulin of the proband revealed that the ratios of normal insulin to abnormal insulin were 8:3 in urine and 1:7 in serum, respectively. These results suggest that excretion of abnormal insulin in urine is much less than that of normal insulin.

Adult↗
PubMed1986

Structurally abnormal insulin in a diabetic patient. Characterization of the mutant insulin A3 (Val----Leu) isolated from the pancreas.

We have recently identified a diabetic patient with marked fasting hyperinsulinemia. Family study revealed that the abnormality was an autosomal dominant trait. High-performance liquid chromatography (HPLC) profile of the patient's serum insulin showed that she had an abnormal insulin in addition to a normal insulin. We have purified her insulin(s) from the specimen of her pancreas, which was biopsied during an operation of cholelithiasis. Insulin was also immunologically purified from the serum of her portal vein. The reverse-phase HPLC analysis revealed that the ratios of normal to abnormal insulin in the pancreas, portal vein, and peripheral vein were 5:4, 4:5, and 1:7, respectively. Radioreceptor assay for insulin using guinea pig kidney membrane revealed that the binding activities of the normal component insulin, the abnormal component insulin and her pancreatic insulin containing both components were 100, 5, and 50% of standard human insulin, respectively. The biological activities of the normal component, the abnormal component and her pancreatic insulin to stimulate glucose oxidation in rat adipocytes were found to be 100, 8, and 60% of standard human insulin, respectively. Analysis of amino acid sequences of the abnormal insulin purified from her pancreas strongly suggested the substitution of leucine for valine at the third position of the A chain, A3 (Val----Leu).

Adolescent↗
PubMed1986

A new case of abnormal insulinemia with diabetes. Reduced insulin values determined by radioreceptor assay.

A 44-yr-old Japanese woman was found to have diabetes with marked fasting hyperinsulinemia. Her fasting plasma glucose, serum insulin, and C-peptide levels were 137 mg/dl, 204 microU/ml, and 1.13 pmol/ml, respectively, and the C-peptide-to-insulin molar ratio was markedly reduced. Insulin antibodies and insulin-receptor antibodies were negative. Fasting levels of counter-insulin hormones were normal. She had normal hypoglycemic response to exogenous insulin injection. Binding of 125I-labeled insulin to erythrocytes was normal. Oral glucose-tolerance tests in eight members of her first-degree relatives revealed four members (mother, sister, brother, and daughter) with fasting hyperinsulinemia (111-314 microU/ml), and two of them (mother and sister) were overtly diabetic. Thus, the abnormality was thought to be an autosomal dominant trait. Reverse-phase high-performance liquid chromatograph analysis of immunopurified insulin obtained from her serum revealed two peaks of insulin immunoreactivity. The amount of the abnormal insulin peak was seven times greater than that of normal insulin. The abnormal insulin was eluted after bovine, human, and porcine insulins, indicating it has a more hydrophobic nature than normal human insulin. Radioreceptor assay (RRA) for serum insulin with guinea pig kidney membrane revealed that the binding activity of their serum insulin was markedly decreased. Discrepancies between the values measured by RRA and those measured by radioimmunoassay were also found in her family members with hyperinsulinemia but not in her family members without hyperinsulinemia and other hyperinsulinemic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗