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Biomedical subjects

A Ohyama

Publications and source records attributed to A Ohyama.

At least 37 records · Page 2Linked to original sources
PubMed1996

[Comparison of the effects of halothane, isoflurane and sevoflurane in the treatment of severe asthmatic attack: a case report].

A 19-year-old woman suffered from a severe asthmatic attack. She did not respond to any of the conventional therapies and eventually lapsed into a state of unconsciousness. We administered isoflurane 1-2% via an endotracheal tube, but, she still required a ventilator. This study was carried out in order to compare the effects of halothane, isoflurane and sevoflurane in the treatment of a severe asthmatic patient. The inhalation of isoflurane, halothane and sevoflurane decreased the airway resistance and systemic vascular resistance in direct relationship to the dosage administered. Because the patient's metabolic rate is low and the occurrence of arrhythmias is rare with isoflurane, we concluded that isoflurane is the best alternative for the patient with asthma.

Adult↗
PubMed1995

Temporal and spatial patterns of gene expression for the hatching enzyme in the teleost embryo, Oryzias latipes.

The hatching enzyme of the medaka, Oryzias latipes, consists of two proteases, high choriolytic enzyme (HCE) and low choriolytic enzyme (LCE). They are synthesized and accumulated in the same unicellular hatching glands and are secreted from them at the end of embryonic development to digest the egg envelope. Recently, these enzymes were purified, and their cDNA clones were isolated. In the present study, we examined temporal and spatial patterns of expression of the hatching enzyme genes during embryogenesis using cDNAs for HCE and LCE as probes. According to Northern blotting analysis, the expression of both genes started at the same time (stage 21-22 embryos: brain differentiation and lens formation) and the patterns of expression changed in parallel during development. In situ hybridization to whole embryo and the sections revealed that the expression of the HCE genes was detected first in the anterior end of the hypoblast layer in stage 16-17 (late gastrula) embryos. Distinct signals of the HCE gene expression were then detected in a group of cells located at the front of the head rudiment of embryos at stage 18-19 (1 somite). Treatment of the embryos with retinoic acid, which is known to affect the anterior differentiation of embryos, suppressed the hatching gland cell differentiation in accordance with the result of in situ hybridization. In stage 22 embryos, the HCE-positive cells dispersed in an ectodermal layer under the forebrain and optic vesicles. Thereafter, the hatching gland cells expressing the HCE mRNA were aligned along the branchial arches and finally rearranged to the inner wall of the pharyngeal cavity, following a marked elongation of the lower jaw. The results of in situ hybridization to whole embryos at consecutive developmental stages demonstrated that the hatching gland cells located at the most anterior portion of the hypoblast migrated posteriorward to endoderm (pharyngeal endoderm) by way of ectoderm, while they were expressing mRNA for the hatching enzyme. Retinoic acid treatment of embryos gave rise to aberrations in the final location of the hatching gland cells probably by disturbing their migration. Moreover, the number of hatching gland cells increased markedly during their migration. This fact strongly suggested a concurrence of gene expression and mitosis of a gland cell and/or a successive initiation of gene expression in maturing gland cells during migration.

Animals↗
PubMed1995

Immunohistochemical proof of intraneural localization of herpes simplex virus in experimental retinitis.

A unilateral intravitreal inoculation of herpes simplex virus type 1 (HSV-1) induced bilateral retinitis and encephalitis in the rat. Immunohistochemistry was employed to clarify the pathway of transmission of HSV-1 from the inoculated eye to the contralateral eye, and to identify localization of the viral antigen in the retina, optic nerve and brain. At an early stage of the post-inoculation period, HSV-1 immunoreactivity was first seen in the cytoplasm of Müller cells and then in various cells of the inner nuclear layer in the inoculated eye. At a later stage, HSV-1 immunoreactivity was seen in some retinal ganglion cells and optic nerve fibers in the inoculated eye. In the brain, HSV-1 was found in the optic chiasm, bilateral primary visual centers (bilateral suprachiasmatic nuclei, bilateral lateral geniculate nuclei, bilateral superior colliculus and bilateral pretectum) and bilateral visual cortex. HSV-1 was also demonstrated in the retinal ganglion cells, neural cells in the inner nuclear layer, and Müller cells in the contralateral eye. We found that HSV-1 antigen in the retina of the contralateral eye was transmitted through the optic nerve, visual pathway and nuclei, but not through the blood stream.

Animals↗
PubMed1994

Intracellular membrane traffic of human immunodeficiency virus type 1 envelope glycoproteins: vpu liberates Golgi-targeted gp160 from CD4-dependent retention in the endoplasmic reticulum.

The membrane traffic of human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins has been investigated in COS-1 cells transiently expressing the HIV-1 env, vpu, and rev genes. Analysis of oligosaccharide processing revealed that the majority of gp160 remained fully endo-H sensitive throughout a 21-h chase period, and hence cleavage of gp160 to gp120-gp41 took place prior to the creation of hybrid and complex oligosaccharides on gp120. Immunofluorescence microscopy demonstrated that in the absence of CD4 both gp160 and Vpu are targeted to the Golgi apparatus, that can be stained with wheat germ agglutinin or antibodies to the human KDEL receptor. In contrast, gp160 complexed with CD4 was retained in the ER and thus failed to reach the cis-Golgi compartment. Although gp160-bound CD4 has its own half life of 4 h 35 min in the endoplasmic reticulum (ER), co-expression of Vpu accelerated the turnover of CD4 by 5.5-fold and thereby enabled gp160 to be translocated out of the ER to the cis-Golgi compartment. We concluded that Vpu prevents the formation of stable CD4-gp160 complexes in the ER and thus indirectly allows gp160 to accumulate in the Golgi apparatus, where it is selectively retained to produce gp120-gp41.

Biological Transport↗
PubMed1994

Interaction with the Rev response element along an extended stem I duplex structure is required to complete human immunodeficiency virus type 1 rev-mediated trans-activation in vivo.

Expression of structural proteins of human immunodeficiency virus type 1 requires the direct interaction of the viral Rev trans-activator with its cis-acting RNA target sequence, the Rev response element (RRE). The originally defined 234-residue RRE, however, failed to show the full HIV-1 regulator of virion expression (Rev) response when inserted into a test plasmid that lacked the flanking env sequences. Here, we demonstrate that an alternative 351-residue complete RRE, which carries an extended Stem I structure, is required for the full Rev-responsiveness in vivo. Mutagenesis studies revealed that the association of Rev with RRE was initiated by the recognition of a functional bubble structure in stem-loop II, followed by interaction with the neighbouring duplex RNA, including the elongated Stem I structure. We propose that, as has been previously shown in vitro, the Rev-RRE interaction in vivo is an ordered assembly process and is based on the association of Rev molecules with the double-stranded region of RRE.

Base Sequence↗
PubMed1994

[Immunohistochemical localization of herpes simplex virus type 1 in experimental retinitis--2. The brain, contralateral optic nerve and retina].

Unilateral intravitreal inoculation of herpes simplex virus type 1 (HSV) induced bilateral retinitis and encephalitis in rats. In a previous paper, we demonstrated immunohistochemical localization of HSV in the ipsilateral retina. In this paper, we report immunohistochemical localization of antigen to HSV in the brain and opposite eye. HSV was found in the optic chiasm, and bilaterally in the suprachiasmatic nuclei, lateral geniculate nuclei, superior colliculus, pretectum, and visual cortex. HSV was also found in the retinal ganglion cells, neural cells in the inner nuclear layer, and Müller cells in the opposite eye. We demonstrated HSV infection in the retina of the opposite eye via the optic nerve, visual pathway, and nuclei, but not through the blood stream.

Animals↗
PubMed1993

[Systemic hemodynamics and renal blood flow in glycerol induced acute renal failure].

In our previous papers, we reported change in the systemic hemodynamics in rats with glycerol-induced acute renal failure, as estimated by the microsphere method. It was found that the development of acute renal failure related not only to renal blood flow, but also to the hepatic blood flow. In view of the liver playing an important role in the metabolism of substances, such as drugs, and in blood circulation, we examined changes in the systemic circulation and blood chemistry in rats with thioacetamide-induced liver cirrhotic, and those rats injected with glycerol. The result indicated that liver cirrhotic rats showed hypertension, higher levels of atrial natriuretic peptide (ANP) and lower levels of renal blood flow relative to the control rats. However, after glycerol injection, the development of acute renal failure was suppressed in liver cirrhotic rats. These results suggest that liver cirrhotic rats were in a hyperdynamic state and that this condition would be beneficial in the prevention of glycerol-induced development of acute renal failure.

Acute Kidney Injury↗
PubMed1993

[Immunohistochemical investigation on intraneural localization of herpes simplex virus type 1 in experimental retinitis. 1. Observation of the retina and optic nerve on the injected side].

In order to examine transfer of herpes simplex virus type 1 (HSV-1) in the retina and optic nerve in rats with experimental retinitis, an HSV-1 suspension (Miyama strain, 1 x 10(7) plaque-forming units per ml, 10 microliters) was inoculated into the vitreous body. One to seven days after HSV-1 inoculation, the animals were perfused through the heart with Zamboni's fixative. Fifty-microns-thick cryostat-cut sections through the retina and optic nerve were immunostained for HSV-1 antigen with rabbit anti-HSV-1 antiserum and avidin-biotin-peroxidase complex. Some sections were counterstained with hematoxylin. At an early stage of the postinoculation period, HSV-1 immunoreactivity was first seen in the cytoplasm of Müller cells and then in various cells of the inner nuclear layer. HSV-1 immunoreactivity was extremely dense in the nuclei of these cells, suggesting that HSV-1 replicates in the nuclei and propagates through the cytoplasm to the membrane of cell processes. At a later stage of the postinoculation period, HSV-1 immunoreactivity was seen in some retinal ganglion cells and optic nerve fibers. The labeling of the optic nerve fibers was found even in the optic tract and often accompanied by labeled glial cells adjacent to the nerve fibers.

Animals↗
PubMed1992

Effect of ciclosporin on cardiac output and regional blood flow in rats: ciclosporin-induced nephropathy and its prevention with calcium channel blocker.

The effect of ciclosporin (CS) on cardiac output (CO) and regional blood flow was studied using the microsphere method in heminephrectomized rats with and without renal arterial clamping prior to the administration of CS. The effect of a calcium (Ca) channel blocker, verapamil, was also examined on CS-induced nephropathy. CS at a dose of 40 mg/kg per day was given orally using a gastric tube for 7 days. Verapamil was given in the drinking water for 7 days. Significant increases in blood urea nitrogen (BUN) and serum creatinine (sCr) with a significant decrease in renal inulin clearance (CIn) were noted after 7 days of CS administration in both intact and ischemic-kidney groups, indicating the development of CS-induced nephropathy. The ischemic-kidney group showed a significantly severe nephropathy as compared with the intact-kidney group. As for change in CO and regional blood flow, CS caused a significant decrease in CO, renal blood flow (RBF) and brain blood flow, while hepatic arterial blood flow and muscular blood flow significantly increased. The renal outer cortical blood flow decreased markedly while the inner cortical blood flow remained unchanged. Although verapamil slightly but significantly decreased mean arterial blood pressure in CS-treated rats, CO and its distribution did not change. BUN and sCr were not significantly ameliorated in the intact-kidney group. However, in the ischemic-kidney group, verapamil caused a significant improvement in RBF, ameliorating CS-induced elevation of BUN and sCr, and a decrease in CIn.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Application of two-color immunofluorescence staining to demonstration of T-cells and HLA-DR-bearing cells in rheumatoid synovitis.

We studied the localization of T-cells and HLA-DR antigen-bearing (DR+) cells in rheumatoid synovitis by employing an improved two-color immunofluorescent staining (TCIF) technique. With this technique we have successfully identified DR+ activated T-cells in the inflammatory synovium. T-cells expressed HLA-DR antigen when they were in contact with DR+ antigen-presenting cells (APC). In addition, activated T-cells showed characteristic distribution within the synovium: they were found around high endothelial venules, within lymphoid follicles, and in hyperplastic synovial lining, suggesting their involvement in the development of rheumatoid synovial lesions via interaction with synovial DR+ APC lineage cells. These findings may contribute to better understanding of the role of activated T-cells in the histogenesis of rheumatoid synovitis, a typical chronic inflammatory lesion.

Arthritis, Rheumatoid↗
PubMed1992

A novel cDNA clone for acid invertase in tomato fruit.

The sequence of a novel cDNA clone, Aiv-1, for tomato acid invertase was similar to that of TIV1 (Klann et al., 1992) for the enzyme except for a unique intron-like insertion. It is considered that Aiv-1 is derived from either an alternatively spliced mRNA for an isozyme or a pre-mRNA of TIV1.

Amino Acid Sequence↗