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Biomedical subjects

N Hirano

Publications and source records attributed to N Hirano.

At least 91 records · Page 5Linked to original sources
PubMed1993

The route of transmission of hemagglutinating encephalomyelitis virus (HEV) 67N strain in 4-week-old rats.

Four-week-old Wistar rats were inoculated with HEV by different routes. Animals died of encephalitis after intraperitoneal (i.p.), subcutaneous (s.c.) and intravenous (i.v.) as well as intracerebral (i.c.) and intranasal (i.n.) inoculation. However when inoculated subcutaneously, rats died a few days earlier than those inoculated i.p. and i.v., suggesting that the virus might be transmitted to the central nervous system (CNS) by the neuronal route rather than by blood stream. Rats which were inoculated subcutaneously at the site of the neck (group A) began to die on day 4 p.i., a few days earlier than animals inoculated in the foot pad of the right leg (group B). On day 2 and 3 after inoculation, the virus titer in the brain was higher in group A, but group B animals showed higher virus titers in the lumber region of spinal cord than group A animals. In order to follow the virus spread from the peripheral nerve to the brain, the virus was inoculated into the sciatic nerve of rats. The inoculated rats developed clinical signs on day 4 and began to die on day 6. On day 2, virus was detected in the posterior half of the spinal cord and migrated toward the anterior half and in the brain where it was present on day 3. The highest virus titers in the brain were recorded on day 4 to 6, meanwhile the virus titers in the spinal cord tend to decrease. By immunohistochemical study, antigen positive neurons were found in the spinal cord and brain on day 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1993

Co-existence of gonadotrophins (FSH, LH) and thyrotrophin (TSH) in single anterior pituitary cells of the musk shrew, Suncus murinus.

According to recent immunocytochemical studies of anterior pituitary cells, it is obvious that the "one cell-one hormone" theory must be modified. Many pituitary morphologists have demonstrated that there are some cells that contain two hormones. In this study, we demonstrate by means of immuno-electronmicroscopy the co-existence of gonadotrophins (FSH and LH) and thyrotrophin (TSH) in the same anterior pituitary cells of the musk shrew. These cells were remarkably altered in their ultrastructural features by either gonadectomy or thyroidectomy. Double labeling for gonadotrophins and thyrotrophin was present not only in the same cells but also in the same secretory granules. Our ability to demonstrate co-existence of gonadotrophins and thyrotrophin in the same cell may be due to our selection of fixative and embedding media for electron-microscopic immunocytochemistry. Our conclusion that gonadotrophins and thyrotrophin are produced in a single cell type of the anterior pituitary gland in the musk shrew, i.e., thyrogonadotrophs, suggests the need to consider a modification of the classic scheme for classification of anterior pituitary cells.

Animals↗
PubMed1993

Modification of tryptophan 149 of inorganic pyrophosphatase from Escherichia coli.

1. The inorganic pyrophosphatase from Escherichia coli was almost completely inactivated on chemical modification of Trp-149 with N-bromosuccinimide (NBS). 2. The presence of a complex of Mg2+ and a substrate analogue, iminodiphosphate (PNP), provided considerable protection against the inactivation, whereas Mg2+ or PNP alone afforded only slight protection.

Amino Acid Sequence↗
PubMed1993

Trumpet laminectomy for lumbar degenerative spinal stenosis.

The clinical and radiologic results of trumpet laminectomy, an improved method of extensive laminectomy preserving the facet joints (n = 35), and extensive laminectomy (n = 15) were compared in patients with degenerative lumbar spinal stenosis. The results were evaluated using a rating system and serial radiographs and a follow-up of 2 to 10 1/2 years (mean, 5.2 years). The overall results corroborate the advantage of the trumpet laminectomy, demonstrating a lower incidence and lower grade of postoperative lumbar scoliosis as well as less symptom recurrence in the trumpet laminectomy group than in the extensive laminectomy group. Risk factors for postoperative spinal instability and scoliosis appear to be facet joint destruction and elderly females with a high level of physical activity.

Aged↗
PubMed1993

Morphologic variation of lumbar posterior longitudinal ligament and the modality of disc herniation.

The authors investigated the relationship between the type of lumbar disc herniation (471 discs) and the gross anatomy of the posterior longitudinal ligament (PLL) in the lumbar region of 10 cadavers. The size of PLL diminished significantly as the disc level became lower (P < 0.00001), and there are loose attachment of the central area of rhomboidal expansion of PLL. In the upper lumbar region, central or central-lateral herniation with an intact PLL was predominant. The type of disc herniation appeared to be influenced by the width and development of the PLL with a loosely connected central area. In the lower lumbar region, posterior-lateral extrusion with a ruptured PLL was predominant. This may be related to the small or poorly developed PLL in lower lumbar/lumbosacral region. It is suggested that the type of disc herniation (PLL intact or ruptured) is related to the morphologic variation of PLL.

Aged↗
PubMed1993

Structural variation of the anterior and posterior anulus fibrosus in the development of human lumbar intervertebral disc. A risk factor for intervertebral disc rupture.

A morphologic comparison of the laminated structure of the anterior and posterior anulus fibrosus of lumbar intervertebral disc was made on 24 L3-4 and L4-5 discs obtained from 10 fetus, one child, and one young adult cadavers. Low power microscopic and polarized microscopic observations and measurements on the transverse sections were performed to assess 1) lamellar bundle arrangement, 2) number of distinct lamellar bundles, 3) percentage of incomplete lamellar bundles, and 4) fiber-interlacing angles. The number of lamellar bundles was greater in the anterior anulus than in the posterior anulus. A very complex structure was observed in the posterior middle anulus in all the specimens, with a high percentage of incomplete/discontinuous lamellar bundles and greater fiber-interlacing angles. Loose connection of the lamellar bundles of posterior outer anulus was observed in fetal discs. The annular strength was not measured in the present study, however, the risk of posterior disc rupture in the young may be influenced by an inherent structural variation with a weak posterior anulus fibrosus.

Adult↗
PubMed1992

Molecular cloning of bovine actin-like protein, actin2.

Actins are major cytoskeletal components and highly conserved in evolution. In mammals, there are six actin isoforms, a pair of which shows at least 93% identity in the amino acid sequence. We have cloned cDNA for a bovine protein that is distantly related to members of the mammalian actin isotypes. The predicted amino acid sequence (418 residues long, calculated molecular mass 47369) shows that this protein, which we have named actin2, exhibits 36% identity to mammalian actins and 60% identity to the yeast actin-like protein, act2. We have concluded that actin2 defines a new class of mammalian actin-like proteins. It was also revealed that actin2 messenger RNA is expressed in a broad range of tissues.

Actins↗
PubMed1992

Distribution of gonadotrophins within the anterior pituitary cells of the musk shrew (Suncus murinus L.).

Gonadotrophs in the anterior pituitary gland of the musk shrew were first identified by means of electron microscopic immunocytochemistry. The gonadotrophs of the musk shrew revealed quite unusual ultrastructural features that have never been seen before in other species. These cells contained two types of secretory granules, i.e., small dense, round-shape granules and large lucent, irregular-shape granules. FSH beta and LH beta were mostly observed together on both small and large secretory granules. The distribution pattern of the subunits of gonadotrophs was slightly altered following gonadectomy in the musk shrew.

Animals↗
PubMed1992

Cutaneous T-cell lymphoma associated with granular lymphocytic leukemia in its terminal stage.

A 79-year-old woman had cutaneous T cell lymphoma. After a long clinical course, numerous tumors and an enormous increase in peripheral granular lymphocytes without lymphadenopathy developed suddenly. Surface markers and DNA analysis of the tumor cells from her skin and peripheral blood and electron microscopic examination suggested that granular lymphocytic leukemia had developed in the terminal stage of cutaneous T cell lymphoma. To our knowledge this association has not been reported previously.

Acute Disease↗
PubMed1992

Extraperitoneal anterolateral discectomy for lumbar disc herniation: indications, techniques, and time-related clinical results.

We analyzed 80 consecutive cases of lumbar disc herniation who underwent an extraperitoneal anterolateral discectomy according to clinical and radiologic parameters. The average follow-up period was 5 1/2 years (range, 1-10 years). The results of 71 patients (89%) were satisfactory through the mid- and long-term follow-up periods, although a very slight decrease in subjective/objective scores and ADL score was found. Satisfactory results were obtained for adolescent and younger male adults and in isolated central or centrolateral herniations with a broad base. From an analysis of the nine reoperated cases, we determined that the contraindications of this technique are a sequestrated or extruded nucleus pulposus and disc protrusion accompanied by posterior dislocation of a vertebral edge fragment. The relative indications include a small, hard posterolateral herniation located just beneath the nerve roots, double-level herniation, disc herniation accompanied by narrow spinal canal, and bulged disc in elder patients. The absolute indications for this surgery are a centrally or centrolaterally protruded disc with a relatively broad base of herniation at single-disc level that is not accompanied by spinal stenosis in adolescent and younger male adults.

Adolescent↗
PubMed1992

Effects of continuous quantitative vibration on rheologic and biological behaviors of the intervertebral disc.

The authors attempted to investigate the effect of vibration on the physiologic behavior of the intervertebral disc from rheologic and biological responses. Using fresh disc-cartilaginous end plate complexes of porcine coccygeal vertebrae, the frequency characteristics of dynamic compressive elastic modulus and dissipated energy were monitored by means of a biomechanical spectrometer. The effect of vibration on proteoglycan synthetic rates and solute transport in the intervertebral disc were analyzed using a radioisotope. When the disc-cartilaginous plate complexes were subjected to sinusoidal vibration with a static load of 5 N and a vibratory load of 3 N, the elastic modulus decreased at 11 Hz compared with 3.5 Hz. After this, it increased again at 35 Hz. The dissipated energy increased rapidly with an increase in frequency. Proteoglycan synthetic rates did not change appreciably down to the inner and outer layers of the anulus fibrosus, but the rate in the nucleus pulposus alone decreased remarkably at 10 Hz and 35 Hz. Solute transport increased as a response to vibration, particularly in the nucleus pulposus. When the intervertebral disc is exposed to vibration for a long period of time, therefore, the proteoglycan content in the nucleus pulposus may be decreased, eventually resulting in disruption of matrix integrity.

Animals↗
PubMed1992

Results of expansive laminoplasty for lumbar spinal stenosis in active manual workers.

Expansive laminoplasty was done on 18 selected patients with lumbar spinal canal stenosis who were active manual workers and 2 patients with cauda equina tumors from 1982 to 1990. Postoperative follow-up on the initial 10 cases of spinal stenosis was 1-7 years (mean, 3 years). Using computed tomography, the spinal canal was found to be enlarged with a nearly rectangular shape, and the mean percent enlargement was 119% (1.9 cm2). Spinal stability also was reinforced. The preoperative mean evaluation score (Japanese Orthopaedic Association score) was 10.4 (full scale, 29). The mean score improved to 24 postoperatively (mean percent improvement, 73%). These findings did not change during the long follow-up, and the satisfactory results were maintained.

Adult↗
PubMed1992

Familial predisposition and clustering for juvenile lumbar disc herniation.

The siblings and parents of 40 patients (cases) with lumbar disc herniation (aged 18 years or younger) who underwent surgery at the Department of Orthopaedics at Toyama Medical and Pharmaceutical University Hospital between 1976 and 1990 were examined for incidence of lumbar disc herniation. A total of 120 randomly sampled, age- and sex-matched patients (controls) who were hospitalized during the same period due to extraspinal diseases also were studied in the same manner. A survey of the occurrence of definite lumbar disc herniation was carried out that included 75,237 students in elementary, junior high, and senior high schools in Toyama Prefecture, Japan, covering a mean period of 3 years and 4 months. The incidence of surgically treated lumbar disc herniation among people aged 18 years or younger was calculated, and the expected value of disc herniation was obtained in an age-specific manner, on the basis of the age distribution of encumbrances in the above case-control study. The encumbrances of 18-year-old or younger patients with lumbar disc herniation showed familial predisposition, with an odds ratio of 5.61 in comparison to the controls. It was suggested that there is familial clustering of lumbar disc herniation among the encumbrances of 18-year-old or younger patients with lumbar disc herniation.

Adolescent↗
PubMed1991

The role of histidine-118 of inorganic pyrophosphatase from thermophilic bacterium PS-3.

Treatment of the inorganic pyrophosphatase from thermophilic bacterium PS-3 with diethyl pyrocarbonate resulted in the almost complete loss of its activity, which followed pseudo-first-order kinetics. The presence of Mg2+ prevented the inactivation. Enzyme inactivated with diethyl pyrocarbonate was re-activated by hydroxylamine. The inactivation parallelled the amount of modified histidine residue, and a plot of the activity remaining against the amount of modified histidine residue suggested that the modification of one of two histidine residues totally inactivated the enzyme. The site involved was found to be located in a single lysyl endopeptidase-digest peptide derived from the ethoxy[14C]carbonylated enzyme. Amino acid analysis and sequence analysis of the peptide revealed that it comprised residues 96-119 of the inorganic pyrophosphatase from thermophilic bacterium PS-3. These results, when compared with those reported for the Escherichia coli and yeast enzymes, imply that His-118 of the inorganic pyrophosphatase from thermophilic bacterium PS-3 is located near the Mg(2+)-binding site and thus affects the binding of Mg2+.

Amino Acids↗
PubMed1991

Elevation of nerve growth factor synthesis by constitutive expression of v-src oncogene in cultured rat fibroblasts.

Rat fibroblast 3Y1 cells transformed by Rous sarcoma virus (RSV) or transfected with the v-src gene showed a highly constitutive v-src gene expression. Simultaneously, marked increases in the cellular level of nerve growth factor (NGF) mRNA and NGF content in the culture medium were observed. The levels of NGF mRNA and NGF secreted into the medium were correlated with the expression level of v-src mRNA gene in both transformants and control 3Y1 cells. These results suggest that v-src gene expression is relevant to regulation of NGF synthesis in rat 3Y1 fibroblasts.

Animals↗
PubMed1991

Modification of a single tryptophan of the inorganic pyrophosphatase from thermophilic bacterium PS-3: possible involvement in its substrate binding.

The effect of N-bromosuccinimide (NBS) on the activity of the inorganic pyrophosphatase (PPiase) from thermophilic bacterium PS-3 was studied. The enzyme was almost completely inactivated on chemical modification with NBS, depending upon the concentration of NBS. The presence of a complex of Mg2+ and a substrate analogue, imidodiphosphate (PNP), provided extensive protection against the inactivation, whereas Mg2+ or PNP alone showed no protective effect. Amino acid analysis of the NBS-modified enzyme after hydrolysis with 6 M HCl indicated no change in the amino acid composition. However, the magnetic circular dichroism (MCD) bands around 293 nm due to the tryptophan residue and the optical density at 280 nm, decreased concomitantly with modification by NBS. These results strongly suggested that the tryptophan residue at position 143, which is the only tryptophan residue per subunit in the thermophilic PPiase (Ichiba, T., Takenaka, O., Samejima, T. and Hachimori, A. (1990) J. Biochem. 108, 572-578), might be involved in the active site or be located in the vicinity of the active site. The circular dichroism (CD) spectrum in the far ultraviolet region showed no significant alteration during the modification, indicating that the polypeptide chain backbone of the enzyme remained unaltered. However, the modification considerably altered the CD bands in, the near ultraviolet region, indicating that a conformational change occurred in the vicinity of the active site in the enzyme molecule.

Bacteria↗
PubMed1991

Changes in prolactin cells caused by partial hepatectomy in the rat.

In order to study ultrastructure alterations in prolactin (PRL)-secreting cells, PRL cells of the anterior pituitary glands of partially hepatectomized female rats were observed by the protein A-gold procedure with the electron microscope. Simultaneously, their serum PRL and estradiol (E2) levels were measured by radioimmunoassay. After about 70% hepatectomy PRL cells were remarkably changed, that is active granule extrusion, prominent Golgi vesicles and a hypertrophic rough endoplasmic reticulum were observed. These changes were most remarkable on day 3 after the operation. Significant increases in serum PRL and E2 were also seen following partial hepatectomy. It may be assumed that the morphological changes in PRL cells and the elevation of serum PRL were probably due to surgical stress and to the diminution of E2 receptors in the liver after partial hepatectomy in the rat.

Animals↗