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Biomedical subjects

M Sakamoto

Publications and source records attributed to M Sakamoto.

At least 775 records · Page 43Linked to original sources
PubMed1983

Biosynthesis and distribution of opioid peptides.

Group III opioid peptides are derived from proenkephalin B. The processing of this precursor peptide is still only partly understood and we still do not know how many final products come from proenkephalin B and whether Leu-enkephalin is produced from Group III peptides. However, potent biologic activity of Group III opioid peptides and existence of opiate-receptors specific for these peptides (k receptors) strongly suggest that Group III opioid peptides are not precursors of Leu-enkephalin but bioactive substances per se. Further studies should clarify details of the processing of proenkephalin B.

Adrenal Medulla↗
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

Urinary N-acetyl-beta-D-glucosaminidase and beta 2-microglobulin in 'itai-itai' disease.

N-acetyl-beta-D-glucosaminidase (NAG) activity in urine was measured in patients with 'itai-itai' disease, from chronically advanced cadmium poisoning. Elevation of NAG activity, however, was not so marked as that of beta 2-microglobulin (beta 2-MG) in the urine of patients and suspected patients. We conclude that the beta 2-MG test is more valuable than the NAG test for evaluating the severity of the renal tubular damage in chronically advanced cadmium (Cd) poisoning.

Acetylglucosaminidase↗
PubMed1983

Influence of temperature and relative humidity on human rotavirus infection in Japan.

A climatologic analysis of human rotavirus infection in inpatients with acute diarrhea was conducted over a seven-year period. The infection frequency appeared to be related to temperature, but not to relative humidity. Human rotavirus infection was found to appear abruptly when the mean temperature of any 10-day period became less than 5 C (November or December), reached a peak when it was less than 0 C (January and February), and waned when it became greater than 20 C (June and July) in the city of Yamagata in northern Japan.

Adolescent↗
PubMed1983

Purification and characterization of streptomycin 6-kinase, an enzyme implicated in self-protection of a streptomycin-producing micro-organism.

Streptomycin 6-kinase of the streptomycin-producing strain Streptomyces griseus HUT 6037 was purified by fractionation with (NH4)2SO4 and chromatography on DEAE-Sephadex A-25, hydroxyapatite and Sephadex G-100. After PAGE of the final fraction, a protein band corresponding to streptomycin 6-kinase was detected, together with a less intense band having no enzyme activity. Molecular weights determined by SDS-PAGE and by Sephadex G-100 chromatography were about 36000 and 38000, respectively, suggesting that the enzyme was a monomer. The isoelectric point of the enzyme was pH 6.6. Among the nucleoside 5'-triphosphates tested, ATP was the preferred phosphoryl donor. The Km values for streptomycin and ATP were 3.5 mM and 0.4 mM, respectively. The enzyme activity was strongly inhibited by EDTA and AgNO3. It was shown by using an in vitro protein-synthesizing system that purified streptomycin 6-kinase could protect polyphenylalanine synthesis of the streptomycin-susceptible S. griseus strain KSN from inhibition by streptomycin.

Kinetics↗
PubMed1983

Ring chromosome 10 and its clinical features.

A 2-year-old boy with mental and growth retardation is presented; he has a 46,XY,r(10)(p15q26) chromosome complement. Five previously reported cases of ring chromosome 10 were reviewed and compared with the present case in an attempt to delineate a clinical syndrome. Since the first description, identified by Giemsa banding by Lansky et al, four other r(10) patients have been described. Their common features were mental and growth retardation, low birth weight, microcephaly, stubby nose, hypertelorism, strabismus, wide set nipples, single transverse palmar creases, undescended testes, and hypoplastic scrotum. In some of the cases congenital heart disease was present.

Child, Preschool↗
PubMed1983

Zinc-binding proteins of newborn rat epidermis.

Hematoxylin stain was used to demonstrate localization of Zn2+-binding proteins in the skin of the newborn rat. The binding protein showed different solubilities and the zinc binding was dissociated at pH 4.5. Epidermal proteins were extracted stepwise in Tris-HCl buffer containing NaCl at 4 degrees C and 37 degrees C, 1 M potassium phosphate, and 4 M urea. Zn2+-binding protein was obtained from each extract by means of Zn2+ chelate affinity chromatography. We detected elution of histidine-rich protein from the affinity column with a pH 4.5 buffer by 3H-histidine labeling and immunoreactivity to rabbit IgG directed to histidine-rich protein. Amino acid analysis demonstrated that the compositions of the Zn2+-binding proteins soluble in the different extracts not only resemble each other, but are essentially the same as those of histidine-rich protein of the newborn rat skin as previously reported. However, sodium dodecylsulfate gel electrophoresis showed multiple protein bands ranging from Mr less than 25,000 to Mr greater than 200,000. The findings indicate that histidine-rich protein of different forms and solubility exists, in the epidermis and may be involved in the biological function of the cells through metal-binding.

Amino Acids↗
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

[Experimental study on synergism between cefotaxime and ampicillin against Streptococcus D group].

Cefotaxime (CTX) disks and ampicillin (ABPC) disks exhibited synergism against 24 strains of Streptococcus D group isolated from various sources in our hospital. We were interested in these synergism effects and compared them with the combination index. Twenty-two out of the 24 strains examined exhibited synergism, and were identified as Streptococcus faecalis by the API strep system. We divided them into 4 groups (combination index: 19, 15, 11, 9) according to the degree of synergism. Another 2 strains showed additive effects (combination index: 1), and were identified as Streptococcus faecium. Among these 24 strains, beta-lactamases were produced by only 1. There was no direct connection between beta-lactamase production and synergism. The mechanism of synergism between CTX and ABPC has not yet been studied.

Adolescent↗