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Biomedical subjects

H Taniguchi

Publications and source records attributed to H Taniguchi.

At least 487 records · Page 27Linked to original sources
PubMed1990

Heterogeneity of islet cell autoantibodies in terms of insulin release from rat islets and insulinoma cells.

The clinical significance of cytoplasmic islet cell autoantibodies (ICA) has been studied since their discovery by Bottazzo et al. in 1974. Some ICAs destroy pancreatic B cells in the presence of complement, whereas others take no part in this destruction. This suggests that islet function varies with the amount of ICA produced. In the present investigation we report the heterogeneity of monoclonal islet cell antibodies produced by one of us in terms of insulin release from isolated rat islets as well as from rat insulinoma cells (RINr).

Adenoma, Islet Cell↗
PubMed1990

Relationship between age and autonomic neuropathy in diabetes mellitus.

The influence of age on diabetic autonomic neuropathy was studied. In the present study autonomic neuropathy was assessed by cardiac beat-to-beat variation during deep breathing (BBV) and pupil area prior to photic stimulus (A1). In the studies on BBV a total of 440 subjects (11-82 years in age) were divided into three groups: those with a duration of diabetes of less than 5 years and without obvious diabetic complications; those with a duration of diabetes of longer than 5 years and with diabetic complications; and non-diabetic, healthy subjects. The relationship between BBV and age was examined in each group. In the studies on A1 a total of 101 subjects (22-75 years in age) were investigated in the same way. The results were as follows: (1) The autonomic nerve function of young diabetics corresponds to that of old non-diabetics in terms of cardiac beat-to-beat variation and pupil area prior to photic stimulus; (2) in young diabetics duration of diabetes and the complications influence the autonomic nerve function; (3) autonomic nerve function is related to age. Age is more influential than duration of diabetes and diabetic complications, especially in the older subjects.

Adult↗
PubMed1990

Lack of favorable effect of immunomodulators on outbred syngeneic rodent islet transplantation.

We studied the effect of two immunomodulators, lobenzarit disodium and OK-432, on outbred syngeneic islet transplantation. Six hundred fresh islets taken from two male Wistar rats were transplanted intraportally into other male Wistar rats that had been made diabetic with streptozotocin. Lobenzarit was given to 12 recipients and OK-432 to seven recipients intraperitoneally for 1 month, while nine controls received only intraperitoneal saline. Both drug-treated groups could not maintain lower fasting plasma glucose levels or higher fasting body weights at each time as compared with controls. The islet survival time in lobenzarit-treated (23.5 +/- 8.0 days) and OK-432-treated (25.3 +/- 13.4 days) groups was not longer than that (21.6 +/- 9.4 days) of the control group. All the pancreatic insulin contents of the seven surviving controls, ten surviving lobenzarit and five surviving OK-432 recipients were less than 0.8% of the mean insulin content obtained from 12 normal male rats. The hepatic insulin content of both drug-treated groups was not higher than that of the control group. These results suggest that lobenzarit disodium and OK-432 cannot protect outbred syngeneic islet grafts.

Adjuvants, Immunologic↗
PubMed1990

Heterogeneity of human islet cell antibodies in terms of cross-species reactivity.

There has been no consistent view about the cross-species reactivity of islet cell antibodies (ICA), and no report about their target antigens in the pancreatic islet cells of different species. Therefore, we examined the cross-reactivity of human ICA against rodent pancreatic islet cells, and found at least two types of ICA, one having a comparatively strong cross-reactivity and the other lacking it. Furthermore, using human as well as some rodent pancreatic tissues that had been modified chemically, we came to suspect that the target antigens of ICA were sialic acid residues of glycolipids. Therefore, we suggest that there are at least two types of ICA recognizing sialic acid residues of glycolipids, one reacting with antigen(s) commonly present in human and rat islets, and the other with antigen(s) only present in human islets.

Animals↗
PubMed1990

Possible involvement of cholinergic nicotinic receptor in insulin release from isolated rat islets.

Insulin release is influenced by the autonomic nervous system. Regarding parasympathetic control, previous reports have shown that regulation of insulin release is executed exclusively through muscarinic receptors in the pancreatic islets. In the present study, however, we examined the effect on insulin release at the islet level of various agents affecting the parasympathetic nervous system, especially nicotinic receptor blockers. Pancreatic islets isolated from adult Wistar male rats were incubated with these agents and insulin release in the media was measured. Acetylcholine chloride (10(-5) M), as well as distigmine bromide (10(-6), 10(-5) M), both of which are cholinesterase inhibitors, stimulated insulin release, whereas atropine (5 x 10(-6), 5 x 10(-5) M) suppressed it. On the other hand, serum and IgG from myasthenia gravis patients, containing anti-acetylcholine receptor antibodies, affected insulin release, and alpha-bungarotoxin (10(-9)-10(-7) M), a nicotinic receptor blocker, stimulated insulin release dose-dependently. The present observations suggest that insulin release is influenced by the parasympathetic nervous system, mediated via not only muscarinic but also nicotinic receptors.

Acetylcholine↗
PubMed1990

Cloning and characterization of a gene encoding a new thermostable hemolysin from Vibrio parahaemolyticus.

A new thermostable hemolysin (delta-VPH) gene was cloned from a Kanagawa-negative Vibrio parahaemolyticus strain into vector pBR322 in Escherichia coli K12. The nucleotide and amino acid sequences had no homology with those of the thermostable direct hemolysin (TDH) which causes the Kanagawa phenomenon, and of the thermolabile hemolysin (TLH) of V. parahaemolyticus. The gene was present in all V. parahaemolyticus strains tested and also in one strain of V. damsela.

Amino Acid Sequence↗
PubMed1990

Protection by oral phenylalanine against gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in Wistar rats.

The effect of oral administration of L-phenylalanine on the incidence and histology of gastric adenocarcinomas induced by N-methyl-N'-nitro-N-nitrosoguanidine was investigated in inbred Wistar rats. Oral administration of 6% phenylalanine after 25 weeks of treatment with the carcinogen significantly reduced the incidence and number of adenocarcinomas of the glandular stomach at experimental week 52. Oral administration of high dose phenylalanine significantly increased the basal serum gastrin level and significantly decreased the norepinephrine concentration in the antral portion of the gastric wall, as well as the labelling indices of antral mucosa. These findings indicate that orally administered phenylalanine inhibits the development of gastric cancers.

Adenocarcinoma↗
PubMed1990

Enhancement by neurotensin of experimental carcinogenesis induced in rat colon by azoxymethane.

The effects of neurotensin on the incidence, number, size, and histology of colon tumours induced by azoxymethane (AOM) were investigated in Wistar rats. Rats were given 10 weekly injections of AOM (7.4 mg kg-1 body weight) and were also given 200 micrograms kg-1 of neurotensin in depot form every other day until the end of the experiment. In week 40, prolonged alternate-day administration of neurotensin resulted in significant increases in the number and size of colon tumours and the incidence of adenocarcinomas penetrating muscle layer and deeper. However, neurotensin did not influence the incidence of tumour-bearing rats and the histological appearance of colon tumours. Administration of neurotensin caused a significant increase in the labelling index of the colon cancers but not that of colon mucosa. These findings indicate that neurotensin enhanced the growth of colon tumours, possibly related to its effect in increasing proliferation of colon cancer cells.

Adenocarcinoma↗
PubMed1990

Purification and properties of multiple forms of dihydrodiol dehydrogenase from human liver.

Two acidic and three basic forms of monomeric dihydrodiol dehydrogenase with molecular weights in the range of 36,000-39,000 were purified from human liver. One acidic enzyme (pI 5.2), which was specific for NADP- and dihydrodiols of benzene and naphthalene, was immunologically identified as aldehyde reductase. The other four enzymes oxidized alicyclic alcohols as well as the dihydrodiols using both NADP+ and NAD+ as cofactors, but showed differences in specificity for hydroxysteroids and inhibitor sensitivity. Two of the basic enzymes (pI 9.7 and 9.1) exhibited a 20 alpha-hydroxysteroid dehydrogenase activity and sensitivity to 1,10-phenanthroline, whereas the third basic enzyme (pI 7.6) oxidized some 3 alpha-hydroxysteroids at low rates and was inhibited by cyclopentane-1,1-diacetic acid. Another acidic enzyme, which accounted for the largest amount of enzyme activity in the tissue and appeared in two heterogenous forms with pI values of 5.9 and 5.4, showed a high 3 alpha-hydroxysteroid dehydrogenase activity and was the most sensitive to inhibition by medroxyprogesterone acetate. The Km values of the enzymes, except the pI 5.2 enzyme, for hydroxysteroids (10(-6) to 10(-7) M) were lower than those for xenobiotic alcohols.

Alcohol Oxidoreductases↗
PubMed1990

Cloning and sequencing of the endo-cellulase cDNA from Robillarda sp. Y-20.

An endo-cellulase cDNA has been screened from a Robillarda sp. Y-20 cDNA expression library using polyclonal antibodies (immunoscreening). Western blot analysis showed that recombinant CMCase I fused to beta-galactosidase with the molecular weight of approximately 150,000 was expressed in Escherichia coli Y1090. Sequence analysis of the cloned cDNA revealed that it consisted of 1,136 nucleotides. By comparison of the amino acid sequence deduced from the cDNA and the N-terminal amino acid sequence of the purified protein (residues 1 to 18, determined by protein sequencing), the cDNA was found to lack 44 nucleotides at its 5' end corresponding to residues 1 to 15. Therefore, the mature cellulase (CMCase I) was deduced to be composed of 375 amino acid residues and the molecular weight of its protein was calculated to be 41,004. Yaguchi et al. reported that the N-terminal amino acid sequence of an endo-beta-1,4-glucanase (endo-cellulase) from Schizophyllum commune was homologous with the active site of various hen egg-white type lysozymes, and the homology offered evidence for a lysozyme-type mechanism in enzymatic hydrolysis of cellulase [Biochem. Biophys. Res. Commun. (1983) 116, 408-411]. Pentillä et al. also pointed out that some amino acid homology was found between endo-glucanase I from Trichoderma reesei and the lysozyme of the phage T4 [Gene (1986) 45, 253-263]. From the result of sequence alignment of the endo-cellulase from Robillarda sp. Y-20 and four kinds of lysozymes, there was a possibility that the endo-cellulase from Robillarda sp. Y-20 also hydrolyzes carboxymethyl cellulose by a lysozyme-type mechanism.

Amino Acid Sequence↗
PubMed1990

Edematous changes in the central nervous system of zitter rats with genetic spongiform encephalopathy.

The pathogenesis of progressive spongy degeneration in zitter rats with genetic spongiform encephalopathy was examined histopathologically and biochemically in the context of edematous change in the central nervous system (CNS). Histopathological studies revealed that vacuolation in the CNS of zitter rats progressed with aging and the severity of spongy degeneration was markedly divergent in different areas in the CNS. Edematous change was confirmed by a consistently higher water content in the brain of zitter rats than in that of normal SD/J rats at all ages. Furthermore, a close relationship between spongy degeneration and edematous change in the CNS was demonstrated by regional measurement of specific gravity (SPGR) of brain tissues and quantification of the spongy degeneration by computer-image analysis. The brain regions with lighter SPGR were more severely affected by spongy degeneration. These results suggest that edematous change is related to the pathogenesis of spongy degeneration in the CNS of the zitter rat.

Animals↗
PubMed1990

Pathogenesis of Vibrio parahaemolyticus: intraperitoneal and orogastric challenge experiments in mice.

It has been noted that V. parahaemolyticus isolated from patients with food poisoning are almost always thermostable direct hemolysin (TDH)-positive, whereas, isolates from foods or environmental sources are usually TDH-negative. The virulence of V. parahaemolyticus in mice was examined by using intraperitoneal and orogastric challenge models, where the strains used were those isolated from patients and foods with food poisoning and included TDH-positive and -negative. The LD50 in mice was estimated to be approximately 10(7) in the former and 10(8) in the latter challenge model. In the mice killed by challenge, either intraperitoneal or orogastric, the following pathological changes were almost always observed: swelling, redness and fluid accumulation in the small intestine, particularly the upper part of it. Histologically, congestion, edema, and vacuolation were observed in mucosal and submucosal tissues; furthermore, ulceration at tips of some villi was noticed. The lethality and pathological finding in mice due to V. parahaemolyticus were demonstrated similarly in both challenge models and irrespective of the TDH phenotype of the strain used. It will be suggested that the findings in challenged mice may be attributed to enteropathogenic factor(s) other than TDH of V. parahaemolyticus.

Animals↗
PubMed1990

'Stereovectorcardiogram' made by stereolithography.

A method for making directly a single solid vectorcardiogram is reported. A solid vectorcardiogram was made by employing an apparatus for production of three-dimensional objects by stereolithography. Stereolithography is a computer-aided manufacturing technique that is practiced in conjunction with computer-aided design and engineering. To design the solid vectorcardiogram, voltages in the X, Y and Z axes obtained according to the Frank lead are memorized in the computer-aided design system. By use of the stereolithography apparatus, the designed solid vectorcardiogram is formed in a vat filled with liquid plastic. In the vat, the plastic changes rapidly from liquid to solid in the presence of ultraviolet light so that a solid vectorcardiogram made of solid plastic may be formed.

Equipment Design↗
PubMed1990

[Products in the fluorometric reaction of purines with 4,5-dimethyl-o-phenylenediamine after oxidation using N-bromosuccinimide].

Twelve purines oxidized with 4,5-dimethyl-o-phenylenediamine (DMPD) was found to react with N-bromosuccinimide (NBS) to give fluorescent derivatives. In this paper, the identification of oxidation and fluorescent products have been described. In compliance with the substituent on purine skelton, three alloxans were obtained from twelve purines after oxidation by using NBS. The three alloxans reacted with DMPD to form two quinoxalines and an alloxazine, all of which being fluorescent.

Alloxan↗
PubMed1990

Emphysematous change in chronic asthma in relation to cigarette smoking. Assessment by computed tomography.

To evaluate the occurrence and the degree of emphysema in chronic asthma in relation to the effect of cigarette smoking, we examined 35 subjects with irreversible airway obstruction (17 nonsmokers and 18 smokers). We performed pulmonary function testing and CT scans on all subjects. The ES was assessed by a visual scoring system on CT scans. Between nonsmokers and smokers, there was a significant difference in the ES (p less than 0.05), but not in the FEV1, TLC, and Dsb/VA (expressed as percent predicted values). The ES was 2.3 +/- 4.7 percent (mean +/- SD) in nonsmoking subjects and 13.7 +/- 16.7 percent in smoking subjects. In all subjects the ES showed significant correlations with Dsb/VA (p less than 0.001) and pack-years of cigarette consumption (p less than 0.001) but did not show correlations with FEV1 and with TLC. We concluded that emphysema can occur in smoking asthmatic subjects because of the effect of cigarette smoking, and CT scans are useful for detecting this emphysematous change.

Asthma↗