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Biomedical subjects

M Harada

Publications and source records attributed to M Harada.

At least 1,153 records · Page 64Linked to original sources
PubMed1983

Purification and properties of dipeptidyl peptidase II from rat kidney.

Dipeptidyl peptidase II (EC 3.4.14.2) from rat kidney was purified to a specific activity of 66.2 mumol/min per mg protein by a series of column chromatographic techniques. The purified enzyme was apparently homogeneous as judged by disc gel electrophoresis. Gel filtration on a calibrated column indicated an apparent molecular weight of 130 000 for the native enzyme. Gel electrophoresis of the denatured enzyme in the presence of sodium dodecyl sulfate in a constant acrylamide concentration resulted in the appearance of a single component for which a molecular weight of 64 000 was calculated. The pH optima for dipeptidyl arylamides and for tripeptides were pH 5.5 and 4.5, respectively, and the isoelectric point was 4.8. Substrate specificity studies indicated that the purified enzyme hydrolyzes specifically N-terminal X-alanine or X-proline from their respective arylamides and from tri- or tetrapeptides, but not from pentapeptides.

Animals↗
PubMed1983

Effect of a new potent H2-receptor antagonist 3[[[2-[(diaminomethylene)amino]-4-thiazolyl]methyl]thio]-N2- sulfamoylpropionamidine (YM-11170) on gastric mucosal histamine-sensitive adenylate cyclase from guinea pig.

The effect of 3[[[2-[(diaminomethylene)amino]-4- thiazolyl]methyl]thio]-N2-sulfamoylpropionamidine (YM-11170), a new thiazole H2-receptor antagonist bearing propionamidine at the terminus of a side chain, on histamine-sensitive adenylate cyclase [ATP pyrophosphate-lyase (cyclizing); EC 4.6.1.1] of gastric mucosa from the guinea pig was studied and compared with that of cimetidine. YM-11170 displaced the concentration-stimulation curve of histamine-sensitive adenylate cyclase to the right with a pA2 of 7.65 (Ki = 2.25 X 10(-8) M). Stimulation of gastric adenylate cyclase by 0.1 mM histamine was competitively inhibited by YM-11170 and cimetidine in a dose-dependent manner, with IC50 values of 5.9 X 10(-7) M and 1.4 X 10(-5) M respectively. Hippocampal histamine-sensitive adenylate cyclase in the presence of 0.1 mM histamine was also competitively inhibited by YM-11170 with an IC50 of 1.1 X 10(-7) M. YM-11170 did not affect Gpp(NH)p-, NaF-, PGE2-stimulated or basal activity of the gastric adenylate cyclase. These data, together with other results, indicate that YM-11170 is a highly selective and potent H2-receptor antagonist which competes with histamine at the receptor site on the histamine-sensitive adenylate cyclase.

Adenylyl Cyclases↗
PubMed1983

Segmental demyelination and remyelination in lumbar spinal roots of patients dying with diabetes mellitus.

Morphometric evaluations of histopathological changes in postmortem materials from three patients with diabetes mellitus with neuropathy, nephropathy, and retinopathy were made on the sural nerve, lumbar spinal roots, lumbar dorsal root ganglion (2 cases), and fasciculus gracilis. In all three patients there was a marked decrease in densities of both the large and the small myelinated fibers in the sural nerves. In the lumbar spinal roots, segmental demyelination and remyelination with or without decrease in the number of myelinated fibers per root was the main finding in both dorsal and ventral roots, being more common in the dorsal roots. At the third cervical segment of the fasciculus gracilis, the myelinated fiber density was slightly decreased in one patient and moderately decreased in the other two. The number of cell bodies of the fifth dorsal root ganglion was within normal limits in the two patients where this was examined, although the median diameters approximated the lower limit found in controls. The potential presence of segmental demyelination and remyelination in dorsal and ventral spinal roots should be considered especially when assessing electromyographic changes and nerve conduction in diabetic patients.

Adult↗
PubMed1983

Androgen, estrogen, and progesterone receptors in peripheral and central zones of human prostate with adenocarcinoma.

For this study a prostate gland was obtained by retropubic total prostatectomy performed on a seventy-six-year-old patient at Gunma University Hospital. A surgical pathologist separated the gland into peripheral and central portions which were clearly divided by a fibrous stroma. Histopathologic examination of each layer revealed different patterns of adenocarcinoma. The cytosol was incubated with [3H]R1881, [3H]estradiol, or [3H]R5020 in the presence or absence of 100-fold excess unlabeled competing, R1881, diethylstilbestrol, or R5020, respectively. In addition, to measure only androgen receptor all androgen tubes contained 1 X 10(-5) M triamcinolone acetonide. Using glycerol density gradient technique, concentrations of androgen, estrogen, and progestogen receptor were measured on both tissues. Specific receptor concentrations were determined by computation of the suppressible binding from the 8S region of the gradients. The ratio of the androgen receptor to progestogen receptor in the central zone was 1.5 to 2.0 while the same ratio in the peripheral zone was 0.3 to 0.5. Estrogen receptor could not be detected in either portion of this gland, possibly because the patient had received large amounts of diethylstilbestrol diphosphate prior to operation. This is the first report of varying hormone receptor profiles in different anatomic zones of the human prostate.

Adenocarcinoma↗
PubMed1983

Purification and characterization of two novel arginine aminopeptidases from Streptococcus mitis ATCC 9811.

Two novel aminopeptidases (I and II) which have specificity for amino-terminal arginine residues and strong sensitivity to divalent cations were purified from Streptococcus mitis ATCC 9811 by a procedure that involved treatment with a lytic enzyme for bacterial cell walls, followed by a series of chromatographies. Enzyme I was obtained as a homogeneous protein as judged by polyacrylamide gel electrophoresis and had a specific activity of 484.8 units per mg protein using L-arginine-2-naphthylamide as substrate; its Km value was 2.6 X 10(-5) M. The molecular weight was estimated to be 62,000, and its isoelectric point was pH 4.4. Enzyme II was purified to a specific activity of 128.0 units per mg protein and had a Km value of 3.8 X 10(-5) M. The molecular weight was estimated to be 360,000, and its isoelectric point was pH 5.7. The pH optima of enzymes I and II were 8.6 and 7.6, respectively. Both enzymes were inactivated by sulfhydryl reagents and metal ions but were markedly activated by EDTA. The chloride ion had an inhibitory rather than a stimulatory effect on the activity of both enzymes. Substrate specificity studies indicated that both the enzymes specifically hydrolyze N-terminal arginine residues from a-aminoacyl 2-naphthylamides and peptides, but they could not attack the L-arginyl-L-prolyl-peptide.

Aminopeptidases↗
PubMed1983

Carbenicillin-hydrolyzing penicillinases of Proteus mirabilis and the PSE-type penicillinases of Pseudomonas aeruginosa.

Three carbenicillin-hydrolyzing penicillinases were found in Proteus mirabilis strains, N-3, N-29, and GN79. The former two strains were isolated in 1978, but strain GN79 was one of our stock cultures isolated in 1965. These penicillinases closely resembled each other, and the PSE-1 and PSE-4 enzymes produced by Pseudomonas aeruginosa, in their substrate profiles and kinetic properties for hydrolyzing various beta-lactams. However, differences were found in their molecular weights and isoelectric points which ranged from 22,000 to 27,000 and from 6.0 to 6.9, respectively. The antiserum against the purified penicillinase of N-29 cross-reacted with the enzyme of N-3 and inhibited its activity by more than 80%. The antiserum also reacted with the PSE-1 and PSE-4 enzymes. The antiserum did not react with the penicillinase from strain GN79 and the PSE-2 and PSE-3 enzymes of P. aeruginosa. Enzyme production in N-3 and N-29 was mediated by R plasmids.

Animals↗
PubMed1983

Gastric blood flow responses to autonomic nerve stimulation and related pharmacological studies in rats.

The effects of autonomic nerve stimulation on rat gastric blood flow (GBF) were studied using a cross thermocouple method. Stimulation of the periarterial nerve bundles along the left gastric artery produced a decrease in GBF which was antagonized by phenoxybenzamine (0.05 mg kg-1 i.v.), but not by propranolol (1 mg kg-1 i.v.). Stimulation of the vagus nerves elicited an increase in GBF, within a latency of 20 s, which was not apparently affected by atropine (0.15 and 1.5 mg kg-1 i.v.) but was completely blocked by hexamethonium (10 mg kg-1 i.v.). The GBF increase due to acetylcholine (0.25 micrograms rat-1 i.a.), was markedly blocked by atropine (0.15 mg kg-1 i.v.). Vagal stimulation also produced both the cholinergic excitation and non-cholinergic inhibition of gastric motility. The vagally induced GBF increase was little affected by any pretreatment with phentolamine, propranolol, indomethacin or aprotinin. These results suggest that sympathetic nerve stimulation creases GBF through alpha-adrenoceptors and parasympathetic nerve stimulation increases GBF through a non-cholinergic mechanism in rats and that the GBF increase may result from a primary dilator effect of vagal stimulation on the blood vessels because of the immediate initiation of the response.

Animals↗
PubMed1983

Impaired cell-mediated immunity in focal glomerular sclerosis.

Cell-mediated immunity (CMI) was evaluated in 8 patients with focal glomerular sclerosis (FGS), 50 patients suffering from chronic mesangial proliferative glomerulonephritis without renal insufficiency and 24 healthy controls. The following parameters were measured: delayed skin reactivity to purified protein derivative, circulating lymphocytes, lymphocyte cell-surface markers (neuraminidase-treated sheep erythrocyte and erythrocyte-antibody-complement rosettes) and functional markers (mitogenic responses to concanavalin A and phytohemagglutinin). The FGS patients with nephrotic syndrome (NS) had a significant depression in CMI, characterized by decreased responses of the lymphocytes to both concanavalin A and phytohemagglutinin, impaired delayed hypersensitivity to purified protein derivative and a decreased proportion of T lymphocytes as compared with normal subjects. In contrast, the levels of all CMI parameters studied in FGS patients in remission and in patients with chronic glomerulonephritis with or without NS did not differ from normal subjects. Thus, the majority of FGS patients with NS demonstrated an impaired response in a CMI assay system. The possible significance of these phenomena in the pathophysiology of FGS is discussed.

Adolescent↗
PubMed1983

Augmentation of bethanechol-stimulated gastric secretion by lowering body temperature in water-immersed rats.

The present study was designed to elucidate influences of hypothermia on gastric secretory response to secretagogues (bethanechol, histamine and tetragastrin) in rats exposed to restraint plus water immersion (36 and 25 degrees C) stress. In vagotomized rats provided with a pH microelectrode, decrease in intragastric pH by bethanechol (75 micrograms/kg, i.p.) was markedly produced under the water-immersion at 25 degrees C and the extent of the pH decrease was significantly greater than that observed under the water-immersion at 36 degrees C. However, intragastric pH decrease by histamine (1 mg/kg, i.v.) or tetragastrin (60 micrograms/kg/20 min, i.v.) was not affected by varying water temperatures. Using a technique of pyloric ligation, gastric acid and pepsin responses to bethanechol were measured at doses of 50-100 micrograms/kg in vagotomized rats and also at doses of 0.5-1.0 mg/kg in vagally intact rats. Stimulation of acid and pepsin secretion by bethanechol was provoked only under the water-immersion at 25 degrees C. As compared with the values obtained under the water-immersion at 36 degrees C, a significant augmentation of bethanechol-stimulated secretion was seen for acid and pepsin output in vagotomized rats and seen for acid output in vagally intact rats under the water-immersion at 25 degrees C. These results suggest that hypothermia may operate some mechanism for increasing the secretory responsiveness of the stomach to cholinomimetics.

Animals↗
PubMed1983

Site of the ganglion blocking action of gardneramine and hirsutine in the dog urinary bladder in situ preparation.

The ganglion blocking site of gardneramine (GA) and hirsutine (HS) was studied in the dog urinary bladder in an in situ preparation. GA and HS selectively inhibited the DMPP-induced contraction without having an antagonistic effect on the McN-A-343-induced and acetylcholine-induced contraction. In addition, since GA and HS showed a local anesthetic action weaker than that of procaine, the effect of procaine was studied on the same preparation. Procaine inhibited the McN-A-343-induced contraction, and it slightly inhibited the DMPP-induced and acetylcholine-induced contraction. From these findings, it is concluded that GA and HS inhibited the ganglionic transmission of the dog urinary bladder and that the blockade of the nicotinic receptor played a main role.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗
PubMed1983

Paraquat-induced enhancement of vascular permeability.

Paraquat, intradermally injected in the dorsal skin of rats, demonstrated three phasic actions; enhancement of vascular permeability within 30 min (Phase I) and at 6-24 hr after the injection (Phase II) by dye leakage method and bleeding in skin at 2-7 days after the injection (Phase III). Phase I was induced in the presence of paraquat in the skin. However, phases II and III occurred in the absence of paraquat. Morphological study indicated inflammatory observations such as infiltration of mononuclear cells and swelling of venular endothelial cells throughout these three phases. And the most severe morphological changes occurred in phase II. Aspirin, indomethacin, tripelennamine and dexamethasone decreased dye leakage but superoxide dismutase increased it in phase I. These drugs including superoxide dismutase decreased dye leakage in phase II. Bleeding in phase III was decreased by the administration of aspirin and indomethacin. Because of higher effective dose of indomethacin used in this experiment as compared with a clinical dose, aspirin seemed among drugs examined in our experimental models to be the most potent drug that depressed the progression of paraquat-induced enhancement of permeability.

Animals↗