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Biomedical subjects

T Ihara

Publications and source records attributed to T Ihara.

At least 163 records · Page 9Linked to original sources
PubMed1985

Effect of dopamine, bombesin and cysteamine hydrochloride on plasma growth hormone response to synthetic growth hormone-releasing factor in rats.

In urethane anesthetized rats, an intracerebroventricular (icv) injection of 2 micrograms bombesin 5 min prior to the administration of synthetic human growth hormone-releasing factor (GRF) (1 microgram/kg, iv) inhibited plasma growth hormone (GH) response, while cysteamine hydrochloride (90 mg/kg, sc) administered 150 min beforehand depleted immunoreactive somatostatin content in the pituitary-stalk median eminence and consequently potentiated the response to GRF. Under the same experimental conditions, central injection of 1.89 micrograms (10(-8)M) dopamine hydrochloride or iv administration of L-DOPA (10 mg/kg) did not influence the subsequent plasma GH response to GRF. Results suggest indirectly that bombesin and cysteamine, but not dopamine, predominantly modulate somatostatin release from the hypothalamus.

Animals↗
PubMed1985

Presence of corticotropin-releasing factor-like immunoreactivity in human tumors.

Corticotropin-releasing factor (CRF)-like immunoreactivity was measured by radioimmunoassay in human organs and tumors associated with and without ectopic adrenocorticotropic hormone (ACTH) syndrome. It was found to be distributed widely in the stomach, pancreas, adrenal gland, and various tumors (e.g., medullary thyroid carcinoma, small cell carcinoma of the lung, pheochromocytoma, and adenocarcinoma of the gastrointestinal tract and pancreas) in a concentration less than one tenth of that of the hypothalamus. Dilution curves of CRF-like immunoreactivity in tissue extracts paralleled that of synthetic rat (human) CRF. Sephadex G-50 gel filtration showed that a major CRF-like immunoreactivity in tissue extracts coeluted with synthetic rat (human) CRF. Results suggest that a material(s) closely related immunologically to CRF is present widely in normal and tumor tissues outside of the central nervous system.

ACTH Syndrome, Ectopic↗
PubMed1985

Analyses of the mRNA transcription processes of Punta Toro phlebovirus (Bunyaviridae).

The time course of the syntheses of Punta Toro (PT) phlebovirus (Bunyaviridae) small (S)-size viral RNA (S vRNA), viral complementary RNA (S vcRNA), and messenger RNA (S mRNA) species has been analyzed using single-stranded DNA probes representing the two S-coded gene products. The data obtained support the conclusion that PT S RNA has an ambisense coding strategy (T. Ihara, H. Akashi, and D. H. L. Bishop, Virology 136, 293-306, 1984) with the viral nucleocapsid protein, N, encoded in a viral-complementary, subgenomic, mRNA species and a putative nonstructural protein, NSs, encoded in a viral-sense, subgenomic, second S mRNA species. In the absence of puromycin (or cycloheximide) full-length S vRNA, S vcRNA, and subgenomic N mRNA and putative NSs mRNA species were identified in PT virus-infected cell extracts. In the presence of inhibitors of protein synthesis (puromycin or cycloheximide) newly synthesized N mRNA species were detected, but not full-length S vcRNA, nor S vRNA, nor the S coded NSs mRNA species. The mRNA species recovered from drug-treated cells have been translated in vitro to synthesize viral N protein. Analyses of the 5' ends of the N and NSs mRNA species have shown them to be heterogeneous in sequence and some 11-18 bases longer than the ends of the genomic RNA species, indicating that they represent nonviral primer sequences like those identified for bunyavirus mRNA species (D. H. L. Bishop, M. E. Gay, and Y. Matsuoka, Nucleic Acids Res. 11, 6409-6418, 1983). The presence of such additional sequences on mRNA derived from representatives of two Bunyaviridae genera appears by these analyses to be a more conserved feature than the S RNA coding arrangement of the respective viruses.

Animals↗
PubMed1985

Human leukocytes kill varicella-zoster virus-infected fibroblasts in the presence of murine monoclonal antibodies to virus-specific glycoproteins.

Seven murine monoclonal antibodies reacting with major glycoproteins of varicella-zoster virus were tested for functional activity in assays for antibody-dependent cellular cytotoxicity (ADCC) and antibody-plus-complement-mediated lysis. Human peripheral blood mononuclear cells killed varicella-zoster virus-infected fibroblasts in the presence of three of four monoclonal antibodies directed against gp98/62 and a single monoclonal antibody directed against gp118. Neither of two monoclonal antibodies directed against gp66 was able to mediate ADCC. In 18-h assays, adherent effector cells were more active than nonadherent effector cells in mediating ADCC. Adherent cells treated with anti-Leu-11b and complement retained their cytotoxic activity, suggesting that monocytes are responsible for most of the adherent-cell-mediated cytotoxicity. Both immunoglobulin G1 and G2a murine monoclonal antibodies were able to participate in ADCC. Of the two immunoglobulin G2a monoclonal antibodies tested, both of which reacted with gp98/62, only one mediated lysis in the presence of complement. These results indicate that some murine monoclonal antibodies against major glycoproteins of varicella-zoster virus have functional activity in cytotoxicity assays.

Antibodies, Monoclonal↗
PubMed1985

Plasma growth hormone response to human growth hormone releasing factor in rats administered with chlorpromazine and antiserum against somatostatin. Effects of hypo- and hyperthyroidism.

The effect of hypo- and hyperthyroidism on the plasma growth hormone (GH) response to synthetic human growth hormone releasing factor (GRF) was determined in conscious, freely moving rats pretreated with chlorpromazine and antiserum against somatostatin. Chlorpromazine plus somatostatin antiserum pretreated rats gave consistent response to GRF which was not observed in untreated rats. Chlorpromazine alone has no effect on GH secretion induced by GRF in rat pituitary monolayer culture. In rats made hypothyroid by thyroidectomy, both basal and peak plasma GH responses to a small (0.25 microgram/kg bw) and a moderate dose of GRF (1 microgram/kg bw) were significantly reduced as compared to controls. In rats made hyperthyroid by the administration of thyroxine, basal and peak plasma GH responses to a small but not to a moderate dose of GRF were significantly reduced as compared to controls. A reduced plasma GH response to a small dose of GRF was observed 8 days after the cessation of thyroxine administration. The pituitary GH reserve was markedly reduced in hypothyroid but not in hyperthyroid rats as compared to their respective controls. These results indicate that plasma GH response to GRF is reduced both in hypo- and hyperthyroidism. The mechanism involved in the phenomenon appears to be different between the two conditions.

Animals↗
PubMed1985

[Transformation of ovarian yolk sac tumor to immature teratoma following chemotherapy].

The patient, a 28-year-old woman, in her ninth week of pregnancy, was operated on for stage Ia, mixed germ cell tumor (grade 3 immature teratoma + yolk sac tumor) of AFP decreased to the normal level. Eight months later, an intrapelvic mass and raised AFP were found. The extirpated recurrent tumor in the pouch of Douglas was a grade 2 immature teratoma with no yolk sac element. FAM chemotherapy was given again, and the patient is alive and well after taking oral UFT. As in testicular germ cell tumors, ovarian germ cell tumors can be converted to a more differentiated tumor following chemotherapy.

Adult↗
PubMed1985

[Estimation of location and size of myocardial infarction from body surface potentials using the ECG inverse solution method].

This paper describes a non-invasive mathematical method for estimating the locations and sizes of myocardial infarction using body surface electrocardiographic mappings. The inverse calculation is the theoretical basis of our method of estimation. First, the boundary integral equations were used to relate body surface and epicardial potential distributions. Next, a spherical harmonic expansion was used to solve the equations in order to obtain the epicardial potentials from the body surface potentials. The validity of the method was assessed by animal experiments and the clinical application. Body surface potentials were recorded using a 128 channel electrocardiographic mapping device equipped with a 16 bit microprocessor. In the animal study, the epicardial potentials were recorded by another potential mapping device simultaneously with body surface potential recordings. In the animal study, 60 epicardial electrodes and a freezing unit were mounted on a elastic fabric sack and attached to the heart. After completion of open chest surgery, freezing myocardial injury was incurred by perfusing -50 degrees C acetone-dry ice cryogen into the freezing unit. Twenty minutes after the start of freezing, ST elevations of the body surface and epicardial potentials were simultaneously recorded. An ST subtraction map was compiled as the difference between the maps before and after the myocardial freezing injury. Then, an inverse calculation was applied to the ST subtraction potentials to estimate the epicardial ST elevation. The geometric parameters of each electrode were determined from stereometry using two-dimensional X-ray images. In the clinical study, the body surface potentials of a patient with old myocardial infarction were recorded. The abnormal Q subtraction map was calculated as the difference between the measured and standard potentials of a normal subject. In the inverse calculation, the geometric shape of the heart and the body surface were determined from cross-sectional body images of computed tomography. The location of the infarction was estimated independently using coronary arteriography and left ventriculography. The results obtained were as follows: Experimentally, the estimated epicardial ST elevations correlated well with the measured ones. The area of estimated ST elevation included the portion of the myocardial injury produced by the freezing procedure, although the area estimated was relatively small compared with the actual one. Clinically, the estimated abnormal Q area correlated well with the area of the left anterior descending artery in which severe stenosis was detected by coronary arteriography.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

[External immobilization of cervical spine with a halo vest--experience with 31 cases].

Post-traumatic or post-operative immobilization of cervical spine often requires long term bed-rest. But, bed-rest indeed gave discomfort to patients, nonetheless, sometimes complete external fixation cannot be gained. Since 1982, we have applied Halo vest to the patients who required external immobilization of cervical spine. In this paper, we reported our experiences with 31 cases who were treated by Halo vest. Thirty-one cases comprised 19 cases of cervical spinal trauma, 5 cases of atlanto-axial dislocation, 1 case of foramen magnum meningioma, and 6 cases of ossification of posterior longitudinal ligament (OPLL). In traumatic cases, Halo vest was used as external fixation of injured spine in 8 cases, and as an adjunct to surgical fusion in other cases. In case of atlanto-axial dislocation, 3 cases underwent posterior fusion, and 2 cases underwent anterior fusion. Anterior fusion of C1-2 was also done in case of foramen magnum meningioma after total excision of tumor. Six cases of OPLL underwent anterior decompression and anterior fusion. Mean immobilization time by Halo vest was as follows: 58 days (28-113) in case of cervical spinal trauma, 85 days (56-144) in case of atlanto-axial dislocation who underwent posterior fusion, 92 days (89-93) in case of atlanto-axial dislocation and foramen magnum meningioma who underwent anterior fusion, 59 days (54-70) in case of OPLL. Early ambulation was achieved in many cases. Good external fixation and result was obtained 27 cases out of 31 cases. Re-dislocation of cervical spine occurred in 1 case of cervical spinal trauma while he was in Halo vest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Pharmacokinetics and clinical evaluation of aztreonam in pediatrics].

Pharmacokinetics, in vitro, and in vivo effect of aztreonam (SQ 26,776, AZT), a newly synthesized monobactam antibiotic, were investigated in pediatric patients. The pharmacokinetics were studied in 12 children without renal or hepatic impairment, each of whom received single 10, 20 and 40 mg/kg intravenous doses of drug. Serial samples of serum and urine were assayed for AZT. Serum pharmacokinetics of AZT were described by an open, linear, two-compartment kinetic model. After intravenous administration, AZT was eliminated primarily by urinary excretion of unchanged drug (60.4%). The average biological half-lives of AZT in serum were 1.33 (10 mg/kg, n = 1), 1.69 +/- 0.40 (20 mg/kg, n = 8), and 1.51 +/- 0.61 (40 mg/kg, n = 3) hours. The antibacterial activity of AZT against E. coli and P. aeruginosa was equal or slightly stronger than that of CPZ, LMOX, and CTX. It had no antimicrobial activity against Gram-positive cocci. In vivo effect of AZT was evaluated in 13 children with various infections. The result was excellent in 7 cases, good in 1 case, fair in 3 cases and poor in 1 case, with effective ratio of 66.7%. Exanthema or elevation of GOT and GPT were noticed in 3 patients.

Adolescent↗
PubMed1984

Histologic grade and karyotype of immature teratoma of the ovary.

Seven cases of ovarian "pure" immature teratoma were encountered in patients 10 to 38 years of age, six cases being in Stage Ia and one case in Stage IIc. The primary tumors and recurrent growth observed in one case were histologically graded from 0 to 3 according to the criteria of Norris et al. Karyotypes of the tumors and the patients were determined using culture and banding techniques. The only nonsurviving case was in Stage IIc. Four primary tumors belonging to grades 0, 1, and 2 showed a normal 46,XX female karyotype and the patients are alive and healthy. Three grade 3 tumors showed various types of karyotype abnormalities (48,XX,+14,+21; 47,XX,+20; 47,XXX). One patient died, one is alive after experiencing a recurrent tumor, and one has only been followed for 22 months. All seven patients had a normal 46,XX female chromosome constitution. Evidence to date indicates that karyotype of ovarian immature teratoma is either normal female 46,XX or a slight deviation from normal. It is postulated that in ovarian immature teratoma normal 46,XX karyotype is an indicator of favorable prognosis, whereas deviations in karyotype suggest a possibility of poor prognosis.

Adolescent↗
PubMed1984

Novel coding strategy (ambisense genomic RNA) revealed by sequence analyses of Punta Toro Phlebovirus S RNA.

Sequence analyses of Punta Toro viral S RNA species indicate the existence of a novel coding strategy for RNA viruses that involves both viral complementary and viral sense mRNA species. The Punta Toro nucleocapsid protein (N, 26.9 X 10(3) Da) is coded by a discrete viral complementary mRNA species corresponding to the 3' half of the viral S RNA. A second, presumably nonstructural, gene product (NS, 29.1 X 10(3) Da) is coded by a viral sense mRNA species that corresponds to the 5' half of the viral RNA. The ambisense nature of the S RNA is unique by comparison with any other viral RNA and raises questions concerning the family assignment of phleboviruses.

Amino Acid Sequence↗
PubMed1984

Varicella vaccine trials in healthy children. A summary of comparative and follow-up studies.

Beginning in 1979, OKA and KMcC strains of varicella zoster virus (VZV) vaccine were administered to 369 healthy seronegative children in a sequence of ten comparative clinical trials. Postimmunization clinical reactivity was minimal with the OKA vaccines but was unacceptably high (32%) with the KMcC passage-40 vaccine. Ninety-three percent to 100% immunogenicity was noted by fluorescent antibody assay and in vitro lymphocyte proliferation to VZV antigens. Follow-up studies demonstrated persistence of antibody and in vitro lymphocyte proliferation responses and protection or modification of infection nine to 48 months after immunization. Only five episodes of mild varicella occurred in children in whom seroconversion had occurred. These episodes were noted after at least 281 known varicella exposures. Vaccine virus reactivation as zoster had not occurred in any child.

Adolescent↗
PubMed1984

Localized conserved regions of the S RNA gene products of bunyaviruses are revealed by sequence analyses of the Simbu serogroup Aino virus.

The complete nucleotide sequence has been determined for the S RNA of Aino virus, a member of the Simbu serogroup (Bunyavirus genus, family Bunyaviridae). The S RNA is 850 nucleotides long (2.76 X 10(5) daltons) and in the viral complementary sequence has a short 5' non-coding region of 34 nucleotides and a more extensive 3' non-coding region of 117 nucleotides. The 3'-5' complementarity of the Aino S RNA is about 25 residues long, depending on the arrangement. The Aino sequence predicts that, like snowshoe hare (SSH) and La Crosse (LAC) bunyaviruses (Bishop, D.H.L., et al. (1982) Nucleic Acids Res., 10, 3703-3713; Akashi, H. and Bishop, D.H.L. (1983) J. Virol. 45, 1155-1158), there are two S coded gene products, a nucleoprotein N, and a non-structural protein, NSS, that are read from overlapping reading frames in the viral complementary sequence. The Aino N primary gene product is composed of 233 amino acids (26.2 X 10(3) daltons) and is 45% homologous in sequence with that of LAC virus. The NSS protein of Aino virus is composed of 91 amino acids (10.5 X 10(3) daltons) and is 35% homologous in sequence with the LAC NSS protein. Unlike those viruses there are no uridylate tracts longer than 4 residues in the 5' non-coding region of the S viral RNA that could function as a template for polyadenylation of Aino S mRNA species.

Amino Acid Sequence↗
PubMed1984

Human polymorphonuclear leukocyte-mediated cytotoxicity against varicella-zoster virus-infected fibroblasts.

Polymorphonuclear leukocytes (PMN) were studied for their ability to mediate cytotoxicity against varicella-zoster virus (VZV)-infected and uninfected human fibroblasts in 51Cr release assays. PMN were capable of mediating antibody-dependent cellular cytotoxicity (ADCC) against VZV-infected targets. Maximal ADCC was obtained with effector-to-target ratios of 100:1 and 18 h of incubation. Percent 51Cr release for 26 normal adults was 14.1 +/- 0.6 (mean +/- standard error) in the presence of pooled human seropositive sera (final dilution, 1:100) and 0.5 +/- 0.6 in the presence of pooled human seronegative sera. Addition of phorbol myristate acetate (PMA) enhanced PMN-mediated cytotoxicity against VZV-infected and uninfected targets. PMA-stimulated cytotoxicity was optimal with PMA concentrations of 200 ng/ml and effector-to-target ratios of 10:1, and antibody was not required; killing was detected as early as 3 h after incubation and was maximal after 18 h. Highly purified PMN were capable of mediating both ADCC and PMA-stimulated lysis. Catalase completely inhibited PMA-stimulated PMN cytotoxicity, but had no effect on PMN-mediated ADCC. PMN from patients with chronic granulomatous disease were capable of mediating ADCC, but not PMA-stimulated killing, against VZV-infected targets. Thus, PMN could kill VZV-infected targets by two different mechanisms: ADCC, which required antibody but not hydrogen peroxide (H2O2), and PMA-stimulated cytotoxicity, which required H2O2 but not antibody.

Adult↗
PubMed1984

[Case of acoustic neurinoma with intratumoral hemorrhage extending to cerebellar hemisphere].

A case of acoustic neurinoma which developed intratumoral hemorrhage extending to the right cerebellar hemisphere, is reported. A 54-year-old man was diagnosed as cerebello-pontine angle tumor, possibly acoustic neurinoma, from typical clinical course, neurological signs and findings of skull X-P and CT scan at the first visit to our out-patient clinic on July 28, 1981. On August 6, 1981, he was transferred to our in-patient ward in emergency because of sudden onset of headache and impairment of consciousness. At emergency admission, he was found to be comatous and CT scan revealed round-shaped high density in the right cerebellar hemisphere, continuing from the right cerebello-pontine angle tumor with enlarged lateral ventricles, which indicated occurrence of intratumoral hemorrhage. At emergency operation, hematoma in the right cerebellar hemisphere was evacuated and the tumor in the right cerebello-pontine angle was partially resected. Microscopically, the tumor was composed of compact, finely fibrillated cells of Antoni A tissues, and loose patterns of Antoni B tissue, being diagnosed as schwannoma, and also abnormal vascular proliferations were identified just adjacent to foci of hemorrhage noted within tumor tissues. The pattern of abnormal vascular proliferations within this tumor were almost identical with telangiectasia. The authors concluded that intratumoral hemorrhage in this case occurred most likely due to disruption of histologically verified abnormal vascular proliferations.

Cerebellopontine Angle↗
PubMed1983

Isolation of new serotypes of bovine rotavirus. Brief report.

Two cytopathogenic bovine rotavirus strains were isolated. The infectivity of both isolates was relatively stable at pH 3.0 and resistant to ether. Their replication was not affected by 5-iodo-2'-deoxyuridine. The new isolates shared immunofluorescent antigen with the Lincoln strain of bovine rotavirus. By neutralization test, however, these strains were clearly distinguished from one another.

Animals↗