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Biomedical subjects

M Oya

Publications and source records attributed to M Oya.

At least 109 records · Page 6Linked to original sources
PubMed1990

PGD phenotyping in bloodstains, organ tissues, dental pulps and hair roots by isoelectric focusing.

Polymorphism of PGD was investigated in bloodstains, organ tissues, dental pulps, hair roots and semen by isoelectric focusing. This technique provided much higher resolution of PGD isoenzymes than starch gel electrophoresis. Phenotyping was possible from bloodstains for 5 weeks, from organ tissues (except pancreas) for 1-3 weeks, from dental pulps for 2 weeks and from hair roots for 2 weeks when they were stored at room temperature. The method is simple, rapid, reliable and therefore useful in medicolegal individualization of bloodstains, organ tissues, teeth and hairs.

Blood Stains↗
PubMed1990

Characterization of the receptors for peptide-YY and avian pancreatic polypeptide in chicken and pig brains.

We have previously identified the peptide-YY (PYY) receptor on porcine brain membranes as a 50-kDa protein after chemical cross-linking. PYY receptors are discretely distributed in the brain of various mammals, to which neuropeptide-Y (NPY), but not pancreatic polypeptide (PP), bind with great specificity. The present study was carried out in order 1) to identify and characterize the PYY receptor in the avian brain, 2) to compare it with the APP receptor that had been demonstrated in the cerebellum, and 3) to examine [125I]APP-binding activity in the porcine brain. [125I]PYY was bound to chicken brain membranes via high affinity (Kd = 2.19 x 10(-10) M) and low affinity (Kd = 1.93 x 10(-7) M) components. The binding sites were highly specific for PYY and APP as well as for NPY and PPP, coupled to a guanine nucleotide regulatory protein, and distributed in various brain areas, including the cerebellum. The C-terminal fragments of PYY, PYY-(17-36) and PYY-(24-36), exhibited low potency in inhibiting binding, but behaved like full agonists. Porcine brain membranes, on the other hand, possessed two orders of the APP-binding sites, a high affinity component (Kd = 4.24 x 10(-9) M) and a low affinity component (Kd = 3.08 x 10(-7) M). APP binding showed a high specificity for APP, but not for PPP, NPY, or PYY. The binding activity was highest in the pituitary gland, followed by the hippocampus, amygdala, cerebral cortex, hypothalamus, and cerebellum. Guanosine 5'-O-thiotriphosphate, a nonhydrolyzable GTP analog, did not inhibit the binding of [125I]APP to porcine or chicken brain membranes, which ran counter to the results of PYY receptors in both species. Cross-linking studies have demonstrated that receptor-bound [125I]APP is cross-linked to a protein of 67 kDa without disulfide-linked subunits in both porcine and chicken brain membranes. In the latter species, [125I]PYY and [125I]NPY were also cross-linked to the same 67-kDa proteins, which were different from the receptor proteins (50 kDa) in mammalian species. These results indicate that chicken brain has receptors specific for PYY and NPY, as was found in mammalian brains, and that PYY, NPY, and PP act in the brain through interaction at multiple receptor sites, which are similar to and shared by other members of the PP family. Furthermore, the finding that APP-binding sites in porcine brain are more specific than those in avian brain suggests that an endogenous peptide similar to APP may exist in porcine brain.

Animals↗
PubMed1990

Morphological studies of the cardiac lymphatic system.

The distribution and structure of the mammalian cardiac lymphatic system have been investigated by puncture injection, intra-arterial injection of silver nitrate, hydrogen peroxide immersion, and light and electron microscopy. The cardiac lymphatic system consists of drainage vessels and lymphatic capillaries. The drainage vessels contain many valves and are mainly situated subepicardially following branches of the coronary artery. The lymphatic capillaries are composed of a thin layer of endothelial cells, and form relatively dense networks in a fishnet arrangement. These lymphatic networks are richer in the ventricles than in the atria, being present in the subepicardial myocardial and subendocardial regions. In addition, networks are found in all cusps of the atrioventricular valves, and in the sinuatrial node and atrioventricular system. The lymphatic system maintains cardiac homeostasis by receiving proteins, electrolytes and excess fluid from the interstitial tissue and returning them to the venous system.

Animals↗
PubMed1990

[A study of combined chemotherapy with MMC, ADM, CDDP, etoposide (VP-16), 5'DFUR (MAC-VD therapy) in advanced cancer and local relapse of the stomach].

Eighteen patients with progressive/locally recurrent cancer of the stomach were given therapy with MMC, ADM, CDDP, Etoposide (VP-16), and 5'DFUR (MAC-VD therapy). Drugs were administered intravenously with MMC 10 mg/m2, ADM 20 mg/m2, and CDDP 50 mg/m2 on day 1; orally with etoposide 100 mg/day for five consecutive days from day 3; and orally with 5'DFUR 600 mg/day for three weeks from day 3 followed by discontinuation for one subsequent week. This drug regimen was one course of the treatment and repeated as far as possible. There were 16 evaluable cases; the sex distribution was ten males and six females. Patients ranged in age from 43 to 78 years. P.S. 1 was two cases; 2 ten cases; and 3 four cases. The overall response rate, CR + PR, was 1 + 7/16 (50%), while this rate for primary disease was 2 + 5/16 (43.8%). Of the two CR cases, one primary lesion became operable and CR was demonstrated histologically. The overall response rates, CR + PR, for metastatic lesions were 1 + 3/9 (44.4%) for the liver; 0 + 1/4 (25.0%) for the abdominal lymph nodes; 0 + 1/2 (50.0%) for the superficial lymph nodes; 0 + 1/2 (50.0%) for the bones; and 0 + 1/1 (100%) for the lung. The median duration of the response was 3.7 months (range between 1.5 and 8.2+) and the median duration of survival 5.1+ months (range between 2.2+ and 13.3+). At the same time, the hematological side effects of both leukocytopenia and hypohemoglobinemia were seen in 43.8% of the cases. Non-hematological side effects included alopecia in 18.8% and nausea/vomiting in 12.5%. There was no case of discontinuation due to side effects. It was concluded that the therapy with MMC, ADM, CDDP, etoposide and 5'DFUR (MAC-VD therapy) proved to be a very promising drug regimen in the treatment of stomach cancer with high rates of response and is expected to be a step forward in the establishment of interdisciplinary treatment.

Administration, Oral↗
PubMed1990

[The changes in tumor markers such as serum CEA, CA 19-9, TPA and CA 125 in the chemotherapy of patients with advanced gastric cancer].

Twenty-five patients with advanced gastric cancer were treated with a combination chemotherapy. The levels of serum CEA, CA 19-9, TPA and CA 125 were measured before and during chemotherapy (4 and 8 weeks). One complete and 10 partial responses were obtained, and the response rate was 44%. Pretreatment positive rates of these four tumor markers were all more than 60%, and the positive rate of combination assay was 96%. The mean percent changes of these four tumor markers were similar and correlated well with the response to chemotherapy. There was a significant correlation between tumor reduction and decrease of serum CEA in the responders with measurable lesions. These results suggest that the measurement of changes of serum tumor markers may be useful for monitoring the response to chemotherapy in patients with gastric cancer. It also may be useful to determine early the effectiveness of the treatment.

Adolescent↗
PubMed1989

[A study on PP family peptide receptor: I. The distribution of peptide YY (PYY) receptor in the brain].

Peptide YY (PYY) was discovered in the porcine gut by Tatemoto in 1982. PYY has recently been found in the central nervous system. This has provoked studies of PYY effects when centrally administrated. We investigated the specific binding of radioactive PYY (125I-PYY) to brain membranes in pigs and dogs. PYY chiefly bound to the hippocampus, as well as to the pituitary gland, hypothalamus, and amygdala, suggesting that PYY acts on the limbic-hypothalamic-pituitary axis. PYY binding in the brain had a high-affinity and a low-affinity component (dissociation constant, 1.39 X 10(-10) M and 3.72 X 10(-8) M, respectively). The binding sites were highly specific for PYY and neuropeptide Y (NPY), but not for pancreatic polypeptide (PP) or other peptide hormones such as cholecystokinin octapeptide, methionine enkephalin, adrenocorticotropic hormone, and thyrotropic releasing hormone. The similar affinities for PYY and NPY imply that these peptides regulate brain functions through interaction with common receptor site(s).

Amygdala↗
PubMed1989

Conformational changes of a mitochondrial precursor protein on binding to phospholipid vesicles and SDS micelles. A circular dichroism and fluorescence spectroscopy study.

Conformations of an artificial mitochondrial precursor protein pCox IV-DHFR have been analyzed by CD and fluorescence spectroscopy in the presence of (cardiolipin-rich) phospholipid vesicles or SDS micelles. Binding of pCox IV-DHFR to phospholipid vesicles involves a conformational change, which is presequence-dependent, accompanies alteration in the secondary structure of the DHFR moiety, but is different from total unfolding of the polypeptide chain. On the other hand, a conformational change of the fusion protein on binding to the micelles of a positively charged detergent, SDS, is not presequence-dependent.

Circular Dichroism↗
PubMed1989

A proton nuclear magnetic resonance study on the solution structure of crotamine.

Proton nuclear magnetic resonance (NMR) spectra of crotamine, a myotoxic protein from a Brazilian rattlesnake (Crotalus durissus terrificus), have been analyzed. All the aromatic proton resonances have been assigned to amino acid types, and those from Tyr-1, Phe-12, and Phe-25 to the individual residues. The pH dependence of the chemical shifts of the aromatic proton resonances indicates that Tyr-1 and one of the two histidines (His-5 or His-10) are in close proximity. A conformational transition takes place at acidic pH, together with immobilization of Met-28 and His-5 or His-10. Two sets of proton resonances have been observed for Ile-17 and His-5 or His-10, which suggests the presence of two structural states for the crotamine molecule in solution.

Amino Acid Sequence↗
PubMed1989

Step-wise thermal denaturation of cobrotoxin, a snake venom neurotoxin from Naja naja atra: a proton nuclear magnetic resonance study.

Temperature dependence of proton nuclear magnetic resonance spectra has been followed for cobrotoxin, a postsynaptic neurotoxin from Naja naja atra venom. Several aromatic amino-acid residues, including the functionally essential Trp-29 located at the tip of the central loop of the molecule, have been found to undergo a thermal structural transition above the global thermal denaturation temperature. It is suggested that a local structure around these residues behaves somehow independently of the rest of the molecule, and that such structural organization may be favorable for a conformational change of a neurotoxin molecule on binding to acetylcholine receptor.

Cobra Neurotoxin Proteins↗
PubMed1989

State of functionally essential Trp-29 in snake venom neurotoxins: a proton nuclear magnetic resonance study.

Proton nuclear magnetic resonance (NMR) spectra have been recorded of various neurotoxins from snake venoms. pH dependence of the chemical shifts and resonance intensity has been followed for the functionally essential Trp-29. The indole N-1 proton of Trp-29 in alpha-bungarotoxin, toxin B, and cobrotoxin exhibits appreciably large upfield shifts as the pH is lowered and the suppressed exchange with the solvent hydrogen at pH 3-4, but not in Naja haje annulifera 10 where Asp-31 is replaced with Gly-31. This observation strongly suggests the presence of a hydrogen bond between Trp-29 and Asp-31 that is probably important in stabilizing the arrangement of the functionally essential residues to form a distinct binding region for the receptor.

Elapid Venoms↗
PubMed1989

Effect of neuropeptide Y on the hypothalamic-pituitary-adrenal axis in the dog.

There is increasing evidence that neuropeptide Y (NPY) affects the release of pituitary hormones, including adrenocorticotropic hormone (ACTH). The present study was designed to clarify the mechanism by which NPY activates the hypothalamic-pituitary-adrenal (HPA) axis in the dog. Mongrel dogs were equipped with a chronic cannula allowing intra-third (i.t.v.) or intra-lateral (i.l.v.) cerebroventricular administration. A 1.19 nmol, i.t.v. dose of NPY produced as great an ACTH and cortisol response as did equimolar ovine corticotropin releasing factor (CRF). This action of NPY was dose-dependent and shared by peptide YY (PYY) and pancreatic polypeptide (PP), other members of the PP family peptide. Intravenously (i.v.) administered NPY (1.19-11.9 nmol) was much less potent than i.v. CRF in stimulating ACTH and cortisol secretion. However, i.v. NPY significantly increased plasma ACTH and cortisol concentrations, raising the possibility that NPY may modulate the activity of corticotrophs. We have next investigated the possible relationship between NPY and CRF on the HPA axis. Pretreatment with a novel CRF antagonist, alpha-helical CRF9-41 (130.9 nmol i.t.v. or 261.8 nmol i.v.), partly but significantly attenuated the ACTH and cortisol responses to i.t.v. NPY (1.19 nmol). Furthermore, adding a subthreshold dose of i.t.v. NPY (0.119 nmol) to i.t.v. CRF (1.19 nmol) or i.v. NPY (2.38 nmol) to i.v. CRF (0.595 nmol) resulted in the potentiation of CRF-induced ACTH secretion. These results indicate that NPY may activate the HPA axis in concert with CRF probably at hypothalamic and/or pituitary levels. The present findings that NPY evokes ACTH secretion and potentiates the effectiveness of CRF as a secretagogue, together with high concentrations of NPY in the hypothalamus and pituitary portal blood, suggest that NPY is involved in the multihormonal control of ACTH release.

Adrenocorticotropic Hormone↗
PubMed1989

Effect of cholecystokinin octapeptide analogues on food intake in the dog.

Cholecystokinin octapeptide, administered into the third cerebral ventricle (icv), suppresses feeding in sheep, pigs, chicken, rats, and dogs. Because of the species differences in the feeding response to cholecystokinin (CCK), we studied the pharmacological characterization of this peptide on feeding in 16-h-fasted dogs. We examined the effects of CCK-(26-33)-NH2 (CCK-8) and a variety of its analogues, nonsulfated CCK-(26-33)-NH2 (desulfated CCK-8), CCK-(26-33)-OH (deamidated CCK-8), (Nle28,31)-CCK-(26-33)-NH2 [(Nle28,31)-CCK-8], succinyl-CCK-(27-33)-NH2 (Suc-CCK-7) succinyl-Thr28, Leu29, MePhe33-CCK-(27-33)-NH2 [Suc-Thr28, Leu29, MePhe33)-CCK-7], CCK-(29-33)-NH2 (CCK-5), and CCK-(30-33)-NH2 (CCK-4) on food intake after iv injection. Systemic dose-response studies appeared to reveal the following rank order of potencies: Suc-CCK-7 = Suc-(Thr28, Leu29, MePhe33)-CCK-7 greater than CCK-8 = (Nle28,31)-CCK-8 greater than desulfated CCK-8 greater than deaminated CCK-8 greater than CCK-5 = CCK-4 = 0. Smaller COOH-terminal fragments acted as antagonists to the satiety effects of CCK-8. These data demonstrate in the dog that the structural requirements for the behavioral activity of CCK-8 are the COOH-terminal amide group, the sulfate ester of the tyrosine moiety, and the conformational constraints observed in CCK-7.

Animals↗
PubMed1989

C7 polymorphism in Japanese: new allele C7*8.

The polymorphism of C7 was investigated in neuraminidase-treated sera from 513 unrelated Japanese individuals using isoelectric focusing followed by an electroimmunoblotting technique. Besides the common phenotypes 5 rare variants including 2 types of new variants were detected. The family analysis suggested the hereditary occurrence of a new allele C7*8. The allele frequencies were: C7*1 = 0.8314, C7*2 = 0.0926, C7*3 = 0.0380, C7*4 = 0.0331, C7*6 = 0.0010, and C7*8 = 0.0039.

Alleles↗
PubMed1989

Placental glucose dehydrogenase polymorphism in Japanese.

The polymorphism of glucose dehydrogenase (GDH) was investigated in 516 Japanese placentae. The allele frequencies were GDH*1 = 0.510, GDH*2 = 0.488 and GDH*3 = 0.002. GDH*3 appears to increase from Japan via Southeast Asia and India to Europe.

Carbohydrate Dehydrogenases↗
PubMed1989

Simultaneous determination of FUC and PGM1 by isoelectric focusing.

This paper describes a simple procedure for the simultaneous detection of FUC and PGM1 in semen, seminal stains, dental pulps and hair roots after separation by isoelectric focusing using Ampholine pH 5-7. The gel plate was first stained for FUC using an agarose overlay with a buffer of pH 7.5. After reading the FUC types, the FUC overlay was removed and replaced with an agarose overlay for PGM. The results show that the method is useful in medicolegal individualization of seminal stains and teeth when only small samples have to be examined.

Dental Pulp↗
PubMed1989

Characterization of peptide YY receptors in the brain.

We studied the pharmacological and structural characteristics of peptide YY (PYY) receptors in porcine brain. PYY and neuropeptide Y (NPY) bound with high affinity to crude membrane preparations from the hippocampus, but their C-terminal fragments bound with 30- to 450-fold lower affinity Guanine nucleotides, especially the nonhydrolyzable GTP analog GTP gammas inhibited the binding of [125I]PYY, but other transmitters, hormones, and central nervous system-acting drugs did not, except for gangliosides at high concentrations. These results suggest that PYY receptor binding resides in the N-terminal part of the PYY molecule and is coupled to a guanine nucleotide regulatory protein. To elucidate PYY receptor structure, we used the cross-linking reagent disuccinimidyl suberate to covalently attach [125I]PYY to its receptors in the hippocampus membrane. Gel electrophoresis followed by autoradiography revealed a band centered at the mol wt of 50,000. Competitive inhibition of binding by unlabeled PYY resulted in a parallel inhibition of labeling of the 50,000 mol wt protein. The reducing agent 2-mercaptoethanol did not affect the appearance of this band, suggesting that the PYY receptor does not have subunits connected by sulfhydryl bonds. Furthermore, cross-linking [125I]NPY to its receptors in the porcine hippocampus produced the same 50,000 mol wt band regardless of 2-mercaptoethanol. The identity in the size of NPY and PYY receptors together with their similarities in binding properties including regional distribution and peptide specificity, indicate that NPY and PYY regulate brain function through interaction at a common receptor site.

Animals↗