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Biomedical subjects

M Suda

Publications and source records attributed to M Suda.

At least 181 records · Page 10Linked to original sources
PubMed1983

Parallel distribution of methionine-enkephalin-Arg6-Gly7-Leu8 with methionine-enkephalin, leucine-enkephalin and methionine-enkephalin-Arg6-Phe7 in human and bovine brains.

Using specific radioimmunoassays(RIAs) for methionine-enkephalin(Met-Enk), leucine-enkephalin(Leu-Enk), methionine-enkephalin-Arg6-Gly7-Leu8 (Met-Enk-Arg-Gly-Leu) and methionine-enkephalin-Arg6-Phe7 (Met-Enk-Arg-Phe), we studied the regional distribution of these opioid peptides in human and bovine brains. Met-Enk-Arg-Gly-Leu was distributed in parallel with Met-Enk, Leu-Enk and Met-Enk-Arg-Phe in human and bovine brains. The ratios of molar concentrations of these peptides are almost constant in various regions of human and bovine brains and similar to the ratio of these peptides contained in preproenkephalin A. Gel exclusion chromatography and HPLC coupled with respective RIAs showed the existence of authentic peptides without any detectable high molecular weight forms. These results indicate the parallel distribution of Met-Enk-Arg-Gly-Leu with Met-Enk, Leu-Enk and Met-Enk-Arg-Phe in various regions of human and bovine brains and further suggest that these opioid peptides are derived from the same precursor as that in the adrenal medulla and that the processing of preproenkephalin A is almost complete in human and bovine brains.

Animals↗
PubMed1983

Met-enkephalin-Arg6-Gly7-Leu8 exists together with Met-enkephalin-Arg6-Phe7, Met-enkephalin and Leu-enkephalin in human stomach.

Studies on the nucleotide sequence of cloned DNA complementary to mRNA for preproenkephalin A from adrenal medulla and human pheochromocytoma have revealed that this precursor contains 4 copies of methionine-enkephalin(Met-Enk) and one copy each of leu-enkephalin (Leu-Enk), methionine-enkephalin-Arg6-Gly7-Leu8(Met-Enk-Arg6-Gly7-Leu8) and methionine-enkephalin-Arg6-Phe7(Met-Enk-Arg6-Phe7). We have demonstrated the existence of Met-Enk-Arg6-Gly7-Leu8 together with Met-Enk, Leu-Enk and Met-Enk-Arg6-Phe7 in human gastric antrum, using high performance liquid chromatography(HPLC) coupled with radioimmunoassays for these opioid peptides. The ratio of molar concentrations of these peptides in human gastric antrum is almost equal to the ratio of these peptides contained in preproenkephalin A. Furthermore, gel filtration studies on Sephadex G-50 showed that most of immunoreactivities of these peptides were eluted at the elution position of each synthetic peptide without any detectable immunoreactivities at high molecular weight positions. In addition, most of immunoreactivities of these four opioid peptides were detected in the muscular layer of the gastric antrum. These results indicate the presence of Met-Enk-Arg6-Gly7-Leu8 together with Met-Enk, Leu-Enk, and Met-Enk-Arg6-Phe7 in human gastric antrum and further suggest that these opioid peptides are derived from the same precursor as preproenkephalin A in the adrenal medulla and the processing of preproenkephalin A is almost completed in the human stomach.

Chromatography, Gel↗
PubMed1983

Methionine-enkephalin, leucine-enkephalin methionine-enkephalin-Arg6-Phe7 and methionine-enkephalin-Arg6-Gly7-Leu8 in human pheochromocytoma.

Methionine-enkephalin(met-enkephalin)-, leucine-enkephalin(leu-enkephalin)-, methionine-enkephalin-Arg6-Phe7(met-enkephalin-Arg-Phe)- and methionine-enkephalin-Arg6-Gly7-Leu8(met-enkephalin-Arg-Gly-Leu)-like immunoreactivities(-LI) were studied in 16 pheochromocytomas by radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Phe-LI and met-enkephalin-Arg-Gly-Leu-LI existed together with met-enkephalin-LI and leu-enkephalin-LI in 16 pheochromocytomas. Significant positive correlations were observed among contents of these four opioid peptides in 16 pheochromocytomas. The concentrations of these four opioid peptides in epinephrine producing pheochromocytomas were much higher than those in norepinephrine producing tumors. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe and met-enkephalin-Arg-Gly-Leu together with their high molecular weight forms. These results indicate the co-existence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe, met-enkephalin-Arg-Gly-Leu and their high molecular weight forms derived from preproenkephalin A in human pheochromocytomas and suggest the association of preproenkephalin A synthesis with epinephrine production in human pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed1983

Comparison of the action of putative endogenous kappa-agonists, leumorphin and rimorphin in vitro.

Leumorphin and rimorphin (dynorphin B) were nearly equipotent in inhibiting the contraction of the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum and the rabbit vas deferens. Leumorphin had long duration of action in vitro after wash-out, whereas the duration of action of rimorphin was relatively shorter. These action of leumorphin and rimophin were antagonized less effectively by naloxone than by Mr2266, an antagonist relatively specific for the kappa-receptor. Rimorphin as well as leumorphin inhibits the contraction of the rabbit vas deferens which contains solely kappa-receptors. It is concluded that leumorphin and rimorphin have equipotent opioid activity and act at the kappa-receptor, like other opioid peptides derived from preproenkephalin B.

Animals↗
PubMed1983

Occurrence of methionine-enkephalin-Arg6-Gly7-Leu8 with methionine-enkephalin, leucine-enkephalin and methionine-enkephalin-Arg6-Phe7 in human gastric antrum.

Recent studies on the nucleotide sequence of cloned DNA complementary to mRNA for preproenkephalin from bovine adrenal medulla and human pheochromocytoma have revealed that this precursor molecule contains four copies of methionine-enkephalin (Met-Enk) and one copy each of leucine-enkephalin (Leu-Enk), methionine-enkephalin-Arg6-Gly7-Leu8 (Met-Enk-Arg6-Gly7-Leu8) and methionine-enkephalin-Arg6-Phe7 (Met-Enk-Arg6-Phe7). We have demonstrated the existence of Met-Enk-Arg6-Gly7-Leu8 together with Met-Enk, Leu-Enk and Met-Enk-Arg6-Phe7 in human gastric antrum, using high performance liquid chromatography (HPLC) coupled with radioimmunoassays for these opioid peptides. The ratio of molar concentrations of these peptides in human gastric antrum is similar to the ratio of these peptides contained in preproenkephalin. Furthermore, gel filtration studies on Sephadex G-50 showed that most of immunoreactivities of these peptides were eluted at the elution position of each synthetic peptide without any detectable immunoreactivities at high molecular weight positions. These results indicate the presence of Met-Enk-Arg6-Gly7-Leu8 together with Met-Enk, Leu-Enk and Met-Enk-Arg6-Phe7 in human gastric antrum and further suggest that these opioid peptides are derived from the same preproenkephalin as that in the adrenal medulla and that the processing of preproenkephalin is almost complete in the gut.

Adult↗
PubMed1983

Plasma methionine-enkephalin and leucine-enkephalin in normal subjects and patients with pheochromocytoma.

Plasma methionine-enkephalin-like and leucine-enkephalin-like immunoreactivity (met-enkephalin-LI and leu-enkephalin-LI, respectively) in six normal subjects and six patients with pheochromocytoma were determined. The contents of met-enkephalin-LI and leu-enkephalin-LI in two of six pheochromocytomas were 40- to 50-fold higher and those in the other four pheochromocytomas were less than those in normal human adrenal medulla. The former two patients showed high plasma met-enkephalin-LI and leu-enkephalin-LI levels. As plasma catecholamines levels returned to the normal range after extirpation of tumors, met-enkephalin-LI and leu-enkephalin-LI in plasma became undetectable in these patients. In contrast, neither met-enkephalin-LI nor leu-enkephalin-LI was detected in plasma from the latter four patients. Met-enkephalin-LI and leu-enkephalin-LI concentrations were higher in the adrenal vein than in the peripheral vein in three patients. Plasma met-enkephalin-LI and leu-enkephalin-LI increased concomitantly with catecholamines after glucagon stimulation and during a spontaneous attack in a patient with pheochromocytoma. Plasma met-enkephalin-LI changed in parallel with leu-enkephalin-LI in all cases. High performance liquid chromatography coupled with RIAs has shown that met-enkephalin and leu-enkephalin circulate in plasma from a patient with pheochromocytoma as intact pentapeptides. None of normal subjects showed detectable concentrations of met-enkephalin-LI and leu-enkephalin-LI in plasma (more than 5 pg/ml and 3 pg/ml, respectively). It is concluded that met-enkephalin and leu-enkephalin are released concomitantly with catecholamines from pheochromocytomas.

Adrenal Gland Neoplasms↗
PubMed1983

Heterotrophic bacteria accompanying Stichococcus bacillaris in laboratory cultures.

The number and composition of bacterial microflora accompanying Stichococcus bacillaris in various media with urea was determined. The number of heterotrophic bacteria during 5 days of incubation increased 10-fold. Only some of the isolated bacterial strains were able to grow in medium for algae supplemented with dead S. bacillaris cells. It is suggested that bacteria utilize organic matter released to the medium by S. bacillaris. The most numerous among the isolated bacteria were Enterobacteriaceae. The order of domination by bacterial populations distinguishes nonaxenic cultures of S. bacillaris from cultures of other algae.

Aeromonas↗
PubMed1982

Evidence that dynorphin-(1-13) acts as an agonist on opioid kappa-receptors.

The study concerned the opioid-receptor subtype on which dynorphin-(1-13) acts in in vitro isolated preparations. The potency of dynorphin-(1-13) relative to that of ethylketocyclazocine (Mr 2266), a representative kappa-receptor agonist, in inhibiting the electrically evoked contractions of the guinea-pig ileum was found to be similar to that found with either mouse was deferens or rabbit ileum. Moreover, Mr 2266 was found to be several-fold more effective than naloxone to antagonize the agonist actions of both kappa-receptor agonists such as ethylketocyclazocine, ketocyclazocine and bremazocine, and dynorphin-(1-13) either in the guinea-pig ileum, mouse vas deferens, or in rabbit ileum. Additionally, dynorphin-(1-13) was found to have a significant inhibitory action on the rabbit vas deferens which had been shown to contain kappa-receptors exclusively. The data indicate that dynorphin-(1-13) acts as an endogenous agonist on kappa-receptors.

Animals↗
PubMed1981

Heterotransplantation of human esophageal carcinoma to nude mice.

Transplantation to nude mice of 38 tumors originating from 36 human esophageal carcinomas was attempted. Growth of the grafts was obtained in 17 cases and 3 to 11 serial passages were performed in 4 cases. Tumors inoculated into subcutaneous tissue grew locally, but no metastasis nor local invasions were observed. The histological appearances of the grafts were similar to original tumors.

Adenocarcinoma↗
PubMed1980

Circadian rhythm of intestinal disaccharidases of rats fed with adiurnal periodicity.

The circadian rhythm of the activities of maltase and sucrase of the small intestine were examined in rats kept under conditions of continuous lighting with various fixed feeding periodicities for 20 days. When rats were fed once every 24 h, the enzymes showed circadian rhythmic changes with high activities around the feeding time, and the enzyme rhythm persisted even during subsequent starvation. Similar rhythmic changes in the enzyme activities were found in rats fed once every 48 h. When rats were fed once every 32 h, the enzymes showed rhythmic changes with a period of 32 h, but the activities were lowest during the feeding time. The enzyme rhythm with a period of 32 h was replaced by a 24-h circadian rhythm as soon as the rats were starved. It was concluded that the circadian rhythmic changes in disaccharidase activities are controlled by an endogenous mechanism, and that some circadian time-keeping system participates in this mechanism.

Animals↗