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Biomedical subjects

M Nishi

Publications and source records attributed to M Nishi.

At least 199 records · Page 11Linked to original sources
PubMed1993

cDNA cloning and pharmacological characterization of an opioid receptor with high affinities for kappa-subtype-selective ligands.

The amino acid sequence of a rat opioid receptor, designated as ROR-D, has been deduced by cloning and sequencing the cDNA. The ROR-D expressed from the cDNA exhibits high affinities for ligands selective for the opioid receptor kappa-subtype and low affinities for ligands selective for the delta- and mu-subtypes. RNA blot hybridization analysis indicated that ROR-D mRNA is distributed in cerebrum and brainstem but not in cerebellum.

Amino Acid Sequence↗
PubMed1993

Primary structures and expression from cDNAs of rat opioid receptor delta- and mu-subtypes.

The complete amino acid sequences of rat opioid receptors (designated as ROR-A and ROR-B) have been deduced by cloning and sequencing the cDNAs. The ligand-binding properties of ROR-A and ROR-B expressed from the cloned cDNAs in Chinese hamster ovary cells correspond most closely to those of the pharmacologically defined delta- and mu-opioid receptor subtypes, respectively. RNA blot hybridization analysis revealed that cerebrum and brainstem contain both ROR-A and ROR-B mRNAs, whereas neither ROR-A nor ROR-B mRNAs can be detected in cerebellum.

Amino Acid Sequence↗
PubMed1993

Human islet amyloid polypeptide transgenic mice as a model of non-insulin-dependent diabetes mellitus (NIDDM).

To model islet amyloidogenesis in NIDDM and explore the glucoregulatory role of islet amyloid polypeptide (IAPP), we have created transgenic mice containing a rat insulin-I promoter-human IAPP fusion gene. Expression of human IAPP was localized to the islets of Langerhans, anterior pituitary and brain in transgenic animals; blood IAPP levels were elevated 5-fold while fasting glucose levels remained normal. Amyloid deposits have not been detected in transgenic islets suggesting that other co-existing abnormalities in NIDDM may be required for the formation of islet amyloid. These animals provide a unique model for exploring this hypothesis and other proposed functions of IAPP.

Amyloid↗
PubMed1993

A brain-specific transcript from the 3'-terminal region of the skeletal muscle ryanodine receptor gene.

We have shown previously that the skeletal muscle ryanodine receptor mRNA of approximately 16,000 nucleotides codes 5,037 amino acid residues constituting the calcium release channel in skeletal muscle. In this study, RNA blot hybridization analysis shows that the brain contains an RNA species with an estimated size of approximately 2,400 nucleotides hybridizable with the 3'-terminal region of the skeletal muscle ryanodine receptor cDNA. cDNA cloning and genome analysis indicated that two transcripts differing in their start sites are produced from the skeletal muscle ryanodine receptor gene in a tissue-specific fashion, and that the mRNA in brain may code the carboxyl-terminal region of the ryanodine receptor molecule. cDNA expression experiments suggested that the ATG triplet encoding Met4382 of the skeletal muscle ryanodine receptor can function as a translation initiation codon, and that the expressed protein composed of the carboxy terminal 656 amino acid residues of the receptor is located on the endoplasmic reticulum membrane.

Amino Acid Sequence↗
PubMed1993

Isolation and characterization of seven lyso platelet-activating factors and two lyso phosphatidylcholines from the crude drug "suitetsu" (the leech, Hirudo nipponica).

Nine lyso glycerophospholipids were isolated in the pure state from the crude drug "Suitetsu", which is the dried body of the leech, Hirudo nipponica (Hirudidae). They were identified as 1-O-hexadecyl-(1), 1-O-octadecyl-(2), 1-O-tetradecyl-(3), 1-O-9-cis-hexadecenyl-(4), 1-O-hexadecanoyl-(5), 1-O-pentadecyl-(6), 1-O-15-methylhexadecyl-(7), 1-O-octadecanoyl-(8) and 1-O-heptadecyl-sn-glycero-3-phosphocholine (9). Two of them (5 and 8) are lysophosphatidylcholines and the other seven are lyso platelet-activating factors. One of them has an alkenyl carbon chain.

Animals↗
PubMed1993

Effects of the immunosuppressant FK506 on a penetrating keratoplasty rejection model in the rat.

PURPOSE: The immunosuppressive effects of FK506 on allogeneic corneal transplantation were tested in a rat model. METHODS: Inbred-strain Lewis rats were used as recipients, and Fisher rats were used as donors. Intraperitoneal injection of FK506 (0.3, 1.0, and 3.0 mg/kg per day) was administered for 2 weeks, and the grafts were inspected by clinical evaluation. Mixed lymphocyte culture assay, using lymphocytes from recipients of penetrating keratoplasty as responder cells and irradiated splenocytes from naive Fisher or Brown Norway as stimulator cells, was used to identify allogeneic stimulation. The rejection process was studied by histology and immunohistochemistry. RESULTS: The rat strain combination developed 100% graft rejection in about 2 weeks after the penetrating keratoplasty. FK506 prolonged the graft survival in a dose-dependent manner, as observed by clinical evaluation. In mixed lymphocyte culture assay, Lewis rats that had been primed to allogeneic stimulation at the time of cornea transplantation presented significant proliferation to Fisher stimulator splenocytes. FK506 suppressed this primed lymphocyte proliferation. Immunohistochemical and histologic studies confirmed the clinical evaluations. Untreated rat corneas, at the second postoperative week, presented a large number of helper/inducer T cells, macrophages, IL-2 receptor-expressing cells, and Ia-antigen-expressing cells. In the same period, FK506-treated rats appeared normal and had no cellular infiltration. Corneas rejected after FK506 cessation had less intense cell infiltration than the control corneas. CONCLUSIONS: These data indicate that FK506 prolonged the corneal graft survival and can be a potentially useful drug in the immunotherapeutic arsenal to suppress corneal graft rejection.

Animals↗
PubMed1993

Increased aspartate and glutamate levels in both gastric and colon cancer tissues.

The concentrations of free amino acid and protein-bound amino acid in gastric and colon cancers and also in normal tissues were measured and compared in order to investigate the differences in amino acid metabolism between these cancers. The examined materials were 20 specimens of gastric cancer, with 20 specimens of normal gastric full-thickness layers and 11 specimens of normal gastric mucosal layers, as well as 16 specimens of colon cancer, with 12 specimens of normal full-thickness layers and 16 specimens of normal colon mucosal layers. The amino acid pattern in gastric cancer was more similar to that in the gastric full-thickness layer than the gastric mucosal layer. On the other hand, the pattern in colon cancer was more similar to the colon mucosal layer than the full-thickness layer of normal colon tissue. Comparison between gastric and colon cancers showed that almost all of the protein-bound amino acid levels in gastric cancer were significantly higher than in colon cancer, while, conversely, all of the free amino acid levels except for aspartate, glutamate and glutamine were significantly lower in gastric cancer than in colon cancer. Both in the stomach and colon, the aspartate and glutamate levels in cancer tissues were significantly higher than in normal full-thickness or mucosal layers.

Aspartic Acid↗
PubMed1993

A newborn case of extrarenal malignant rhabdoid tumor.

Malignant rhabdoid tumor is initially differentiated from renal tumors and characterized by extremely rapid growth. We report a newborn case of extrarenal malignant rhabdoid tumor and review the literature.

Diagnosis, Differential↗
PubMed1993

[Correlations between estrogen receptor and prognostic factors of patients with breast cancer. The Kanto Cooperative Study Group of Adjuvant Chemoendocrine Therapy for Breast Cancer, Japan].

We investigated possible correlations between estrogen receptor (ER) and prognostic factors in 3,789 patients with stage II or stage IIIa breast cancer in Japan. The patients with ER-positive tumors showed a significantly better prognosis in the 5-year survival rate and the 5-year disease-free survival rate compared with the patients with ER-negative-tumor. Positivities increased with increasing patient age, with increasing tumor size, and lowering degree of cell differentiation, and no relation was observed between the positivities and tumor sites, obesity index, and lymph-node metastasis.

Adult↗
PubMed1993

Loop-like structure of dGTTG in solution.

A strong NOESY cross peak was observed between G1H8 and G4H8 for a single-stranded tetradeoxyoligonucleotide dGTTG in aqueous solution. If dGTTG is in an expanded form, NOE should not be observed because the distance between G1H8 and G4H8 is estimated to be about 13 A. This NOESY cross peak shows that the guanine residues of the both ends of dGTTG exist with short distance (< 5 A), and that dGTTG has a distorted loop-like structure in aqueous solution. This is the shortest single-stranded oligodeoxynucleotide that has a rigid structure in solution.

Magnetic Resonance Spectroscopy↗
PubMed1993

Ocular manifestations in Japanese patients with human immunodeficiency virus infection.

The ocular manifestations in 65 Japanese human immunodeficiency virus (HIV)-seropositive patients were examined. Based on the cumulative totals, 22 of the cases had acquired immunodeficiency syndrome (AIDS), 17 had AIDS-related complex (ARC), and 35 were asymptomatic carriers (AC), including 4 AIDS cases who had progressed from ARC and 5 ARC cases from AC. Seventy-seven percent of the AIDS cases had ocular manifestations, including cotton-wool spots (50%), retinal hemorrhages (59%), cytomegalovirus retinitis (46%) and pupil abnormalities (14%). The ocular signs were also seen in 71% of the ARC cases and 37% of the AC cases. In Japanese HIV-seropositive patients, ocular manifestations are also as common as in Western HIV-seropositive patients.

AIDS-Related Complex↗
PubMed1993

[Ocular manifestations in human immunodeficiency virus seropositive patients].

Ocular manifestations in 56 human immunodeficiency virus (HIV) seropositive patients were examined prospectively. Eighteen of them had acquired immunodeficiency syndrome (AIDS), 14 had AIDS-related complex (ARC), and 30 were asymptomatic carriers (AC). Two AIDS patients progressed from ARC and four ARC patients from AC. Seventy-two percent of AIDS patients had ocular manifestations, including cotton-wool spots (28%), retinal hemorrhages (44%), cytomegalovirus retinitis (28%) and papilledema (6%). We also found ocular signs in 50% of ARC patients and 40% of AC patients. Since ophthalmologic manifestations are common in HIV seropositive patients, it is necessary for them to undergo a routine series of ophthalmologic examinations.

AIDS-Related Complex↗
PubMed1992

Polymerase chain reaction for the detection of the varicella-zoster genome in ocular samples from patients with acute retinal necrosis.

We used the polymerase chain reaction to detect the virus genome in ocular samples from patients with clinically diagnosed acute retinal necrosis. Four samples from four patients with acute retinal necrosis, and five samples from three patients with other ocular diseases (sarcoidosis, rhegmatogenous retinal detachment, and epiretinal membrane of unknown origin) were evaluated. The samples consisted of aqueous humor, vitreous, or subretinal fluid. Primers were specific for varicella-zoster virus, herpes simplex virus, or cytomegalovirus. The varicella-zoster virus genome was detected in three of the four samples from patients with acute retinal necrosis. Among these three positive samples, two had PstI-site-less point mutation, strains that have been described only in Japan and of low prevalence. Samples from patients with diagnoses other than acute retinal necrosis yielded negative results when varicella-zoster virus primer was used. No sample was positive for herpes simplex virus or cytomegalovirus primers.

Adult↗
PubMed1992

Stimulation of growth by both androgen and estrogen of the EMP-K1 transplantable tumor with androgen and estrogen receptors from human extramammary Paget's disease in nude mice.

BACKGROUND: Experimental approaches using transplantable human tumors in nude mice have greatly improved studies on their pathogenesis and treatment. PURPOSE: We studied the establishment of a transplantable tumor, EMP-K1, derived from extramammary Paget's disease and the morphology and unique hormone dependence of this tumor. METHODS: Tissue fragments from a metastatic skin tumor of an 80-year-old man with primary genital extramammary Paget's disease were implanted into male nude BALB/c mice. Tissue fragments of the established tumor were implanted into 50 castrated male 8-week-old nude mice, which were given injections of 100 micrograms testosterone propionate (TP), 100 micrograms 5 alpha-dihydrotestosterone (DHT), 10 micrograms diethylstilbestrol (DES), or 1, 10, or 100 micrograms 17 beta-estradiol (E2). All injections were administered intramuscularly once daily, starting from the day of transplantation. The established tumors were examined immunohistochemically and biochemically. RESULTS: A transplantable tumor (EMP-K1) was established in the nude mouse. EMP-K1 tumor cells expressed antigens such as carcinoembryonic antigen and epithelial membrane antigen, cytokeratin, and c-erbB-2 protein and contained androgen, estrogen, and progesterone receptors. The growth of the EMP-K1 tumor was stimulated by TP, DHT, DES, and E2. CONCLUSIONS: These results suggest that both androgen and estrogen may stimulate the growth of the same tumor by both androgen receptor and estrogen receptor pathways. IMPLICATIONS: The EMP-K1 tumor is a useful tool for studies on the biology of extramammary Paget's disease, and further studies using these tumors will provide useful information concerning proper hormone therapy.

Aged↗