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Biomedical subjects

H Horie

Publications and source records attributed to H Horie.

At least 19 recordsLinked to original sources
PubMed1995

Mitogen induced proliferation of isolated adult mouse Schwann cells.

The proliferation of neonatal Schwann cells (SCs) in response to mitogenic agents has been well analyzed in vitro, but a limited range of mitogens have been defined. We investigated whether three identified neonatal SC mitogens [glial growth factor (GGF), platelet-derived growth factor BB (PDGF-BB), and basic fibroblast growth factor (bFGF)] are required to stimulate mitosis of adult SCs. Adult SCs were isolated from mouse sciatic nerves by mechanical and chemical dissociation, following three experimental steps: 1) culturing the dissociated cells for 24 hr in 10% FCS-F12 medium, 2) culturing these cells in serum-free medium for the next 48 hr, and 3) purifying adult SCs by differential adhesion. We describe a new method for preparation of SCs from peripheral nerves of adult mouse that provides 99.5% pure SCs populations at cell yields of greater than 3 x 10(3) cells/mg of starting nerve wet weight within 5 culture days. Although mitosis of SCs in culture in response to mitogens requires the presence of serum, the complex nature of serum renders difficult a complete analysis of mitogens required for SCs DNA synthesis, so we examined the proliferating response of adult SCs to GGF, PDGF-BB, and bFGF in serum-free medium. GGF alone had mitogenicity for adult SCs in a dose-dependent manner, and synergistic activation coupling with forskolin was not observed. Neither PDGF-BB nor bFGF was mitogenic for adult SCs when used alone or with forskolin.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Neurovirulence test for oral live poliovaccines using poliovirus-sensitive transgenic mice.

The transgenic mice, ICR-PVRTg21, carrying the human poliovirus receptor gene, were intraspinally inoculated with oral poliovirus vaccine viruses and the viruses that had been derived from a vaccine preparation by passagings at 38 degrees. Dose-dependent incidence of paralysis was observed in the transgenic mice inoculated with any of the viruses used. All transgenic mice showing histopathological lesions in the central nervous system appeared to display clinical signs that resembled those observed in human poliomyelitis. These suggest that relative neurovirulence levels of individual virus preparations can be estimated by values of 50% paralysis dose. Indeed, the parameter correlated well with monkey lesion scores of viruses used. Histopathological changes such as degeneration of neurons resemble those displayed by monkeys and were observed in the spinal cord, medulla oblongata, and pons. Thus, the transgenic mice, ICR-PVRTg21, may become a new animal model in place of monkeys for safety testing of oral poliovirus vaccine preparations.

Animals↗
PubMed1995

Diabetes impairs DRG neuronal attachment to extracellular matrix proteins in vitro.

Attachments of dorsal root ganglion (DRG) neurons from streptozotocin (STZ)-induced diabetic and normal C57BL mice to the following substrates were evaluated in vitro: a) poly L-lysine (PL), b) PL + type I collagen (CL-I), c) PL + type IV collagen (CL-IV), d) PL + laminin (LM) and e) PL + fibronectin (FN). After 6 h in culture, there was no significant difference in the average ratio of cells adhesive to PL between the diabetic (74.9%) and normal group of mice (75.6%). In the normal group, the addition of extracellular matrix (ECM) proteins such as CL-I, CL-IV, LM and FN to PL increased the ratios of cell attachment from 75.6% to nearly 90%. In the diabetic group, however, none of these proteins improved the attachment (the ratio changed from 74.9% to nearly 70%). Survival and neurite extension of attached cells after 48 h in culture were not different between the two groups. These results suggest that the cell-surface receptors, which enable DRG neurons to bind to the extracellular matrix proteins, are impaired by diabetes, resulting in being one of the causes of diabetic neuropathy.

Animals↗
PubMed1995

Point mutations of ras and Gs alpha subunit genes in thyroid tumors.

We studied 43 thyroid tumors including 5 adenomatous goiters, 7 follicular adenomas, 22 papillary carcinomas, and 9 medullary carcinomas with regard to the presence of point mutations in the genes of Gs alpha subunit (Gs alpha), Gi2 alpha subunit (Gi2 alpha), H-ras, K-ras, and N-ras by a polymerase chain reaction-direct sequencing method. An adenomatous goiter and a follicular adenoma showed double mutations at codon 227 and 231, and 4 papillary carcinomas showed mutation at codon 231 of the Gs alpha gene. An adenomatous goiter, a follicular adenoma, and a papillary carcinoma showed a missense mutation in codon 13 of the K-ras gene. There were no such missense mutations of these G-protein or ras genes in medullary carcinomas. These data indicate that the genetic events involved in the oncogenesis of parafollicular C-cells are different from those of thyroid follicular cells, in which missense mutations of Gs alpha and ras genes seem to play important roles in tumorigenesis.

Base Sequence↗
PubMed1995

Two different pituitary adenomas in a patient with multiple endocrine neoplasia type 1 associated with growth hormone-releasing hormone-producing pancreatic tumor: clinical and genetic features.

The clinical and genetic features of a 43-year-old male patient with multiple endocrine neoplasia type 1 were reported. He developed hyperparathyroidism, a GHRH-producing pancreatic tumor, and acromegaly between 1980 and 1983. Because his pituitary gland increased in size even after resecting the GHRH-producing pancreatic tumor, transsphenoidal hypophysectomy was performed six years later. The pituitary contained two histologically-different adenomas composed of somatotroph cells and null cells. Genetic analyses revealed loss of heterozygosity on chromosome 11 in common in the pituitary adenomas, the pancreatic endocrine tumors, and a parathyroid hyperplasia. On the other hand, mutations of ras, p53, Gs alpha, and Gi2 alpha genes were not found in these tumors. The loss of the tumor suppressor gene on chromosome 11q12-13 was involved in the formation of two pituitary adenomas, two pancreatic endocrine functioning tumors, and a parathyroid hyperplasia in this patient, but the tumorigenic factors in the specific endocrine organs remain to be studied.

Acromegaly↗
PubMed1994

Three-dimensional cell aggregation enhances growth-promoting activity of NGF in adult DRG.

After removal of the connective tissues with collagenase-trypsin treatment, DRG explants without nerve fibres from mature rodents regenerated numerous neurites all around the explants in response to NGF. To observe the response in the absence of any non-neuronal cells in the ganglia, we introduced three-dimensional cell aggregates consisting of variable numbers of highly purified isolated adult DRG neurones. In this culture system, the addition of NGF to the medium increased the maximum neurite length, the number of neurites, and the cell survival rate. Furthermore, the magnitude of this effect increased with cell aggregate size. Our results suggest that the addition of NGF produces extensive neurite outgrowth in three-dimensional aggregates of matured sensory neurones in the absence of any non-neuronal cells.

Animals↗
PubMed1994

Critical period for degradation of adult rat retinal ganglion cells and their regeneration capability after axotomy.

The optic nerve (ON) in adult rats was transected intraorbitally followed by retrograde labelling of retinal ganglion cells (RGCs) with fluorescence dye (DiI). A two phase reduction of axotomized RGCs was represented in the retina until 15 days after ON transection. The critical period of RGC loss is around 7 days after axotomy. In this period, the capability of neurite regeneration from RGCs in culture was strongly intensified by ON transection. These findings indicate that the 7th day after axotomy is important for both RGC survival and regeneration.

Animals↗
PubMed1994

Absence of hemodynamic tolerance to nicorandil in patients with severe congestive heart failure.

To evaluate whether hemodynamic tolerance develops to nicorandil, a nitrate and potassium channel opener, 14 patients with chronic heart failure (CHF) were treated with nicorandil and 11 were treated with nitroglycerin (GTN). Doses of GTN or nicorandil were titrated to achieve a > or = 20% reduction in pulmonary capillary wedge pressure (PCWP) within 1 hour, and the infusion was maintained at a constant rate for 24 hours. Both groups of patients had comparable hemodynamic parameters before drug infusions were started. The fall in PCWP was identical after 1 hour infusion of either GTN or nicorandil. In the GTN group, PCWP was not significantly different from the baseline value at 12 hours; however, in the nicorandil group, PCWP remained significantly lower than the preinfusion value for 24 hours. During the study period changes in plasma atrial natriuretic peptide (ANP) concentrations paralleled and correlated with changes in PCWP (r = 0.84, p < 0.001). These findings indicate that CHF patients develop hemodynamic tolerance to GTN within 12 hours of continuous infusion, but not to nicorandil, which remained hemodynamically effective during the 24-hour period of infusion. Furthermore, plasma ANP concentration may be a useful noninvasive index of hemodynamic tolerance during GTN or nicorandil therapy in patients with CHF.

Adult↗
PubMed1994

Nerve growth factor (NGF) restores depletions of calcitonin gene-related peptide and substance P in sensory neurons from diabetic mice in vitro.

Dorsal root ganglion neurons from streptozotocin (STZ)-induced diabetic, genetic diabetic and normal mice were cultured in serum-containing media with or without nerve growth factor (NGF). The immunocytochemical analysis carried out after 1 week in culture revealed that the ratios of neurons immunoreactive to calcitonin gene-related peptide (CGRP) in NGF-free medium in the STZ-diabetic mice (average 23.2%) were significantly lower than those in the normal mice (45.1%). The ratios of neurons immunoreactive to CGRP and substance P (SP) in the NGF-free medium were also lower in the genetic diabetic mice (23.6% and 21.8%) than those in the normal ones (40.7% and 34.2%). However, treatment with NGF restored these reduced immunoreactivities in the diabetic groups in a dose-dependent manner. These results show that NGF can be effective for the diabetes-induced depletion of CGRP and SP in sensory neurons, and suggest its possible role in the prevention and improvement of diabetic sensory neuropathy.

Animals↗
PubMed1994

Diabetes-induced reduction of neuronal survival in hypotonic environments in culture.

Dorsal root ganglion (DRG) neurons from streptozotocin (STZ)-induced diabetic and normal C57BL mice were exposed to three different hypotonic environments (1/2, 1/4, and 1/8 osmolar solutions). After rapid applications of these hypotonic solutions to the neurons, the cell volume autoregulatory mechanism operated in 1/2 osmolar solution but was disrupted in superhypotonic solutions below 1/4 osmolar in both kinds of mice. None of the neurons could survive 12 h after treatment with superhypotonic solutions. On the other hand, a gradual reduction of osmolarity of the culture medium enabled neurons in the normal mice to survive in 1/2 and 1/4 osmolar solutions as well as in an isotonic solution. However, this reduction of osmolarity increased neuronal cell death in the diabetic mice. These results suggest that the ability of DRG neurons to survive in hypotonic environments in culture may be lost in diabetes.

Animals↗
PubMed1994

Regional differences in neurite regeneration of postnatal mouse retinal explants.

Retinal explants from mice at postnatal days 2-15 were three-dimensionally cultured in collagen gel. The regeneration of neurites from the explants was investigated at each stage after birth. The explants from the central region in the retina could not regenerate neurites after postnatal day 9, but those from peripheral regions expressed such ability until postnatal day 12. This regional difference in the disappearance stages of retinal regenerative capability coincides with that of retinal maturation.

Aging↗
PubMed1994

Transgenic mice carrying the human poliovirus receptor: new animal models for study of poliovirus neurovirulence.

Recombinant viruses between the virulent Mahoney and attenuated Sabin 1 strains of poliovirus type 1 were subjected to neurovirulence tests using a transgenic (Tg) mouse line, ICR-PVRTg1, that carried the human poliovirus receptor gene. The Tg mice were inoculated intracerebrally with these recombinant viruses and observed for clinical signs, histopathological lesions, and viral antigens as parameters of neurovirulence of the viruses. These parameters observed in the Tg mice were different for different inoculated viruses. Dose-dependent incidences of paralysis and of death were observed in the Tg mice inoculated with any viruses used. This indicates that values of 50% lethal dose are useful to score a wide range of neurovirulence of poliovirus. The neurovirulence of individual viruses estimated by the Tg mouse model had a strong correlation with those estimated by monkey model. Consequently, the mouse tests identified the neurovirulence determinants on the genome of poliovirus that had been identified by monkey tests. In addition, the mouse tests revealed new neurovirulence determinants, that is, different nucleotides between the two strains at positions 189 and 21 and/or 935 in the 5'-proximal 1,122 nucleotides. The Tg mice used in this study may be suitable for replacing monkeys for investigating poliovirus neurovirulence.

Animals↗
PubMed1993

Macrophage-enhanced neurite regeneration of adult dorsal root ganglia neurones in culture.

To study the effects of macrophages on nerve regeneration, purified low population dorsal root ganglia (DRG) neurones from adult mice were cultured in protein-free medium (PFM) or in conditioned media (CM) from peritoneal macrophages cultured in PFM. In PFM, only 20% of the neurones survived at 5 days in culture, but the macrophage CM more than doubled the proportion of neurone survival and neurite extension of controls. These factors did not act on superior cervical ganglia (SCG) neurones, and were considered as being proteins because of their trypsin-sensitive property. Additionally, they may be different from the previously known neurotrophic factors derived from macrophages, because the target cells and effective concentration of these factors were different from those of known ones. The factors investigated in this study may play an important role in nerve regeneration.

Animals↗
PubMed1993

Isolation and age-related characterization of mouse Schwann cells from dorsal root ganglion explants in type I collagen gels.

A technique for isolation of adult Schwann cells (ScC) from dorsal root ganglia (DRG) is described. Decapsulated DRG explants embedded into type I collagen gels were cultured for 3 days in serum-free medium during which ScC migrated from the explant. These explants were then grown in serum-supplemented medium to allow ScC proliferation. On day 10 the number of ScC isolated from DRG explants per mouse was about 2.5 x 10(5), and the purity was greater than 95%. This culture system provided sufficient numbers of highly purified adult ScC in a shorter culture period (2-3 times) than other methods. We used ScC from this method to determine the age-related changes in attachment, growth, and survival of ScC cultured in serum-free medium. The attachment capacity of adult ScC on type I collagen or polylysine was similar to that of newborn ScC. However, the collagen promoted growth and survival of adult ScC but not that of neonatal ScC, indicating age-related differences of ScC properties in vitro.

Age Factors↗
PubMed1993

Preoperative combined treatment with radiation, intraluminal hyperthermia, and 5-fluorouracil suppositories for patients with rectal cancer.

A clinical trial of a novel modality consisting of preoperative irradiation and intraluminal hyperthermia therapy, with or without 5-fluorouracil (5-FU) suppositories, was conducted on 30 patients with rectal cancer. To create hyperthermia in rectal cancer, an intraluminal electrode connected to a radiofrequency system was devised. Patients were treated preoperatively with a total irradiation dose of 30 Gy, being 3 Gy every 2 days, and 5 applications of hyperthermia given twice a week, with or without 5-FU suppositories, given as 100 mg a day to a total of 2,000 mg. Twenty patients received irradiation, intraluminal hyperthermia, and 5-FU suppositories, being the three-combination treatment, and the remaining 10 received irradiation and intraluminal hyperthermia, being the two-combination treatment. Shrinkage of the rectal cancer was observed macroscopically in 26 patients, resulting in a flattened cancerous crater or shallow ulcer. Microscopic examination revealed a marked decrease in the number of cancer cells. In fact, three resected specimens showed no evidence of cancer cells microscopically. These striking reductions in cancer size enabled us to successfully perform super-low anterior resections in four patients, with anastomoses being made just above the dentate line with a sufficiently safe margin. No serious complications were encountered in this series.

Aged↗
PubMed1993

Paratesticular neuroblastoma with N-myc activation.

The authors describe a case of disseminated neuroblastoma discovered as a paratesticular tumor in a 7-month-old boy. The ectopic adrenal tissues adjacent to the paratesticular tumor and multiple lesions in the adrenal gland and skin suggested the possibility of multifocal primary tumors. Although infantile neuroblastoma diagnosed at less than 1 year of age generally responds well to treatment irrespective of distant metastases, metastases developed, and the boy died of disease within 7 months. All multiple lesions had amplification and overexpression of the N-myc protooncogene, which might explain the aggressive phenotype of this rare case.

Blotting, Northern↗
PubMed1993

Analysis of the Gs alpha gene in growth hormone-secreting pituitary adenomas by the polymerase chain reaction-direct sequencing method using paraffin-embedded tissues.

We investigated the prevalence of Gs alpha gene mutations in growth hormone (GH) secreting pituitary adenomas from Japanese patients with acromegaly. Forty-five GH-secreting adenomas were examined for the presence of point mutations in codons 201 or 227 of the Gs alpha gene using the polymerase chain reaction-direct sequencing method and deoxyribonucleic acid extracted from paraffin-embedded tumor specimens. Mutation of codon 227 of the Gs alpha gene was not observed in any of the tumors, but a mis-sense mutation of codon 201 was identified in two tumors (4.4%). One lesion was a densely granulated GH cell adenoma in a patient with adenomatous goiter and breast cancer. The other was a mixed GH cell-prolactin cell adenoma in a patient with multiple endocrine neoplasia type 1 associated with parathyroid hyperplasia and a pancreatic islet cell tumor. The Gs alpha gene detected in parathyroid tissue and pancreatic tumor tissue was of the wild type in this second patient, and the mutation was specific to the pituitary tumor. These results suggest that point mutations of codons 201 or 227 of the Gs alpha gene may not be important mediators of oncogenesis for GH-secreting pituitary adenomas in Japan.

Adenoma↗