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Biomedical subjects

Y Yoshimoto

Publications and source records attributed to Y Yoshimoto.

At least 19 recordsLinked to original sources
PubMed1992

[Cool storage of fetal rat brain for neural transplantation].

The availability, storage and transportation of donor tissue are major practical problems associated with the potential use of grafted neural cell replacements in neurodegenerative diseases. The capacity to collect and maintain viable fetal neural tissue would facilitate possible clinical applications, and provide opportunities to study various neural diseases. In the present study, we examined the effect of cool storage on the survivability of intraventricular rat fetal ventral mesencephalic grafts (gestational days 15). In all experiments, fetal ventral mesencephalons were dissected out under a dissecting microscope in calcium-free magnesium-free buffer (CMF: 0.15 M NaCl, 0.008 M Na2HPO4, 0.0027 M KCl, 0.0015 M KHPO4, 0.026 M NaHCO3, with 0.1% glucose, 100 micrograms/ml streptomycin, 2.5 micrograms/ml fungizone). Fetal mesencephalic tissue was grafted into the lateral ventricle following pregraft refrigeration in calcium-free magnesium-free buffer at 4 degrees C. Fetal mesencephalic tissue was hibernated for 5, 12, 16, 20, 24, 28, 32 hours (group A, B, C, D, E, F and G, respectively). As a control group, fetal mesencephalic tissue was grafted into the lateral ventricle immediately after dissection. Grafted fetal mesencephalic tissue which had been hibernated for 16 hours or less survived well. There were no significant decreases in the size of grafts among group A, B, C and the control group. In group A, B, C and the control group, clusters of TH-positive neurons and dense networks of neuritic profiles within the grafts provided a morphological appearance reminiscent of the dendritic bundles that characterize the zone reticulate of the substantia nigra in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[A case of transethmoidal encephalocele].

A case of a 3-year-old boy with transethmoidal encephalocele is presented. The patient was found to have bacterial meningitis, which responded well to an intravenous antibiotics therapy. No physical anomaly was evident on examination but plain skull X-ray film showed cloudiness of the left nasal antrum. Coronal CT scan disclosed a defect in the left cribriform plate and soft tissue mass in the left nasal cavity. MRI showed an anterior basal encephalocele protruding into the nasal cavity. Hypothalamic-pituitary system and the optic nerves appeared normal in the sagittal image. CSF rhinorrhea was confirmed by RI cisternography. An operation was performed transcranially. After a left frontal craniotomy, a unilateral bony defect in the cribriform plate and protrusion of the brain was observed subfrontally. The crista galli was intact. The herniated brain substance was transected and partially removed and the bony defect plugged by temporal muscle and covered by lyofirized dura. Microscopic examination of the herniated brain mass revealed gliosis and capillary proliferation. The patient recovered well and there has been no recurrence of CSF rhinorrhea or meningitis. Basal encephalocele is a very rare congenital anomaly. It is reported to constitute 1 to 10% of all encephaloceles. Incidence is estimated as 1 in every 35,000 to 40,000 live births. The anomaly is classified into two subtypes; transethmoidal (TE) and transsphenoidal (TS).(ABSTRACT TRUNCATED AT 250 WORDS)

Child, Preschool↗
PubMed1992

[Intrathecal dissemination of meningiomas; a case report].

A case of the cytologically verified intrathecal dissemination of benign meningiomas was reported. A 36-year-old man was admitted to our hospital because trans-sphenoidal surgery was planned for the repair of CSF rhinorrhea caused by a recurrent pituitary adenoma. The CT scan demonstrated incidental multiple tumors spread throughout in the pontomedullary and ambient cisterns. The head and spinal MRI showed more than fifteen small tumors in the posterior fossa and the thoracic spinal canal. CSF cytology revealed benign fibroblastic or meningotheliomatous meningioma with whorl formation and psammoma body. Several comments were made on the mechanism of the intrathecal dissemination of the meningiomas.

Adult↗
PubMed1991

The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents.

This study examines the effect of a novel immunosuppressive agent FK-506 (FK) on the survivability of embryonic (E14) rat ventral mesencephalic tissue after intracerebral grafting to the lateral ventricle of adult mice. The recipient mice were given FK in doses of 10 mg/kg or 1 mg/kg for 2 weeks postgrafting, at which time they were sacrificed and histologically processed except for one group of animals on the high dose (10 mg/kg). In this group most animals died from side effects of the drug during the following days. Only the mice receiving the high dose of FK displayed healthy grafts without signs of rejection.

Animals↗
PubMed1991

Correlates of cortical bone mass among premenopausal and postmenopausal Japanese women.

Few studies have examined the multifactorial risk factors of bone mass in Asian populations. This cross-sectional study was designed to explore relationships between bone mass and environmental variables, including dietary and life-style factors, in Japanese women living in Japan. A total of 178 Japanese women completed the study: 89 premenopausal, ages 35-40, and 89 postmenopausal, ages 55-60. Midradial bone mineral content (MBMC) and bone mineral content per unit area, referred to as bone density (MBMD), were measured using single-photon absorptiometry. The major results of this investigation were the following: (1) The postmenopausal women differed significantly from the premenopausal women in having lower radial bone parameters, lower mean height, later age of menarche, and higher dietary intakes of carbohydrates, vegetables, and milk with a lower intake of caffeine. (2) Current protein intake was a positive correlate of MBMC in both groups. (3) Intake of vegetables (leafy green, yellow, orange, and white) and current milk intake were positively associated with MBMC in the postmenopausal women. (4) For the premenopausal women, irregular menstrual cycles was a negative correlate of MBMC, and for the postmenopausal women, years of menopause was negatively associated with MBMC and MBMD. Longitudinal studies are needed to establish more conclusively associations among diet, life-style, and reproductive history and bone mass of Japanese women.

Adult↗
PubMed1991

The interferon family stimulates the secretions of prolactin and interleukin-6 by the pituitary gland in vitro.

The effects of interferon-alpha, interferon-beta 1 and interferon-gamma on the secretions of prolactin (PRL) and interleukin-6 by primary cultured rat anterior pituitary cells were examined. These three interferons caused dose-dependent increases in PRL secretion within 30 min, and dose-dependent stimulation of interleukin-6 were weaker than the effects of interleukin-1 and tumor necrosis factor-alpha. These results suggest that interferons regulate PRL secretion from the pituitary gland, and that there may be a pathway in which interferons stimulate PRL secretion through interleukin-6 release.

Analysis of Variance↗
PubMed1991

Interleukin-6 stimulates gonadotropin-releasing hormone secretion from rat hypothalamic cells.

There are reports that both interleukin-1 beta and interleukin-6 (IL-6) stimulate the release of adrenocorticotropin through stimulation of hypothalamic corticotropin-releasing factor. We established a primary culture system for hypothalamic neurons producing gonadotropin-releasing hormone (GnRH) and examined whether IL-6 stimulated their GnRH secretion. We demonstrated immunohistochemically that some of these neurons contained GnRH-like immunoreactivity. In primary cultures of these GnRH neurons, we found that the calcium ionophore A23187 stimulated GnRH secretion in a dose- and time-dependent manner. These hypothalamic cells secreted IL-6 spontaneously, producing about 10 ng/l in 24 h, and their IL-6 secretion was significantly stimulated by E2 at 10(-9)-10(-8) mol/l. This stimulatory effect was observed within 3 h. IL-6 also stimulated the release of GnRH in a dose- and time-dependent manner, and these effects of IL-6 were significantly blocked by anti-IL-6 antiserum. These results suggest that the central action of IL-6 on the GnRH neurons may be an important physiological event in the hypothalamus.

Animals↗
PubMed1991

Mortality among the offspring (F1) of atomic bomb survivors, 1946-85.

We compare the mortality in the years 1946-85 in a cohort of 31,159 children born to parents one or both of whom were exposed to the atomic bombing of Hiroshima and Nagasaki (a parental gonadal dose greater than or equal to 0.01 Sv) with that in a control group of 41,069 children. The average gonadal dose for the exposed parents was 0.435 Sv. The mean age of the cohorts was 28.8 years. In the greater than or equal to 0.01 Sv dose group 1,253 deaths were observed in the subset of children both of whose parents have been assigned DS86 doses. 3.2% were attributed to cancers, 72.9% to all diseases except neoplasms. These proportions in the 0 Sv dose group were about the same. Based on a linear relative risk model, no statistically significant increase in the mortality attributable to diseases other than neoplasms is noted following parental exposure, the excess relative risk being 0.030 (+/- 0.046) per sievert based on the DS86 doses (RBE of neutrons = 20). For fatal cancer, no statistically significant effect of parental radiation dose was also observed. An analysis based on the full sample, using not only the DS86 dose group but also ad hoc dose group, yields essentially the same results as the analysis restricted to the DS86 dose group.

Adult↗
PubMed1991

Thyroid cancer: epidemiological study of thyroid cancer in A-bomb survivors from extended life span study cohort in Hiroshima.

We analysed thyroid cancers which were diagnosed clinically or detected at autopsy during 22 years (1958 to 1979) in a sample of 75,493 study subjects exposed in Hiroshima belonging to the extended LSS sample of the Radiation Effects Research Foundation. One hundred and twenty-five cases of clinical thyroid cancer (15 in males and 110 in females) were confirmed, giving a crude incidence rate per 100,000 person-years of 2.7 for males, 12.4 for females and 8.6 for both sexes combined. There was a significant increase of thyroid cancer with increase of atomic bomb radiation dose (thyroid tissue dose based on T65D) in females and in the sexes combined. This tendency was predominant in those exposed at less than 19 years of age. Compared to the control group, the relative risk in the greater than or equal to 0.50 Gy group was higher at 4.0 for males (not significant) and at 4.3 for females (p less than 0.01). Latent thyroid cancer was detected in 155 cases or 3.5% (2.5% for males and 4.5% for females) of the 4,425 cases that came to autopsy during the same period. Compared to the control group, the relative risk in the 50+ rad group was 1.7 for males (not significant), 2.0 for females (p less than 0.05) and 1.9 for both sexes combined (p less than 0.05). New data obtained from autopsy cases between 1950 and 1985 have been added.

Female↗
PubMed1991

A review of forty-five years study of Hiroshima and Nagasaki atomic bomb survivors. Cancer risk among in utero-exposed survivors.

The Radiation Effects Research Foundation (RERF) continues to conduct a follow-up study initiated some years ago of cancer mortality and incidence among the survivors of the atomic bombing of Hiroshima and Nagasaki exposed in utero. Although only 18 incident cases of cancer were identified in the years 1950-1984 (of which 5 cases were in the 0 dose group), cancer risk appears to increase significantly as maternal uterine dose increases. Only two cases of childhood cancer were observed among these individuals in the first 14 years of life; both had been exposed to greater than or equal to 0.30 Gy. All other cases developed cancer in adulthood, and the cancers they developed are, in the main, the ones known to be elevated in frequency among the postnatally exposed survivors. The estimated relative risk for cancer at 1 Gy (uterine dose) is 3.77. The results suggest that the in utero group may have a higher risk than that seen among exposed adults because the individuals exposed in utero have not reached the major cancer prone age. However, since the observed cases are too few to allow a site-specific review, further follow-up studies are required to determine if the observed increased cancer risk can definitely be attributed to A-bomb radiation, although there appears to be a significant dose-related cancer response.

Child↗
PubMed1991

Mortality and cancer risk among the offspring (F1) of atomic bomb survivors.

The Atomic Bomb Casualty Commission (ABCC) and its successor Radiation Effect Research Foundation (RERF) has over the years conducted many studies to determine possible genetic effects of atomic bomb radiation among the offspring of atomic bomb survivors. Findings concerning mortality and cancer incidence of the offspring are summarized in this chapter.

Child↗
PubMed1991

Effect of TNF-alpha on prolactin secretion from rat anterior pituitary and dopamine release from the hypothalamus: comparison with the effect of interleukin-1 beta.

The effects of human recombinant interleukin-1 beta and -6 and tumor necrosis factor-alpha (TNF-alpha) on the releases of PRL and dopamine were examined using monolayer cultures of rat pituitary cells and hypothalamic cells. The release of PRL from rat pituitary cells in 30 min was increased about 2-fold (p less than 0.05) by 10(5) U/l interleukin-1 beta, 10(5) U/l interleukin-6 or 100 micrograms/l TNF-alpha. TNF-alpha at 100 micrograms/l significantly increased PRL release within 5 min incubation and this effect continued throughout the next 30 min of incubation. Incubation for 5 min with TNF-alpha caused dose-dependent stimulation of PRL release. These cytokines did not modulate [3H]-dopamine release from primary cultures of hypothalamic cells. These results suggest that these cytokines stimulate PRL release directly at the pituitary gland, without modifying the release of dopamine from the hypothalamus.

Animals↗
PubMed1991

[The effect of a new immunosuppressive agent, FK-506, on xenogeneic neural transplantation in rodents--comparison with cyclosporin A].

The present study was performed to compare the immunosuppressive effect of FK-506 (FK) with cyclosporin A (CyA) in xenogeneic neural transplantation in rodents. The solid grafts of embryonic ventral mesencephalic tissue from 14-day rat embryos were transplanted into the right lateral ventricle of 20 mature male mice using a stereotactic approach, and the mice were sacrificed 14 days after transplantation. The removed brains, which were sectioned coronally, were stained with antibodies against glial fibrillary acidic protein (GFAP), Lyt-2 or tyrosine hydroxylase (TH) in addition to hematoxylin-eosin and Nissl stainings. The subcutaneous (s.c.) administration of FK at a dose of 10.0 mg/kg daily for 14 days enabled the neural xenografts to survive and grow (n = 5), although all of the neural xenografts treated with CyA at a dose of 10.0 mg/kg s.c. (n = 5) or FK at a dose of 1.0 mg/kg s.c. (n = 5) daily for 14 days and ones treated without such an immunosuppressive agent (n = 5) were rejected by immunological reactions. We conclude that FK is a more powerful immunosuppressive agent than CyA in xenogeneic neural transplantation as well as in cardiac and renal allograftings.

Animals↗
PubMed1991

[Enzyme immunoassay of urinary apolipoprotein H and its application for detecting incipient diabetic nephropathy].

In order to elucidate the clinical significance of urinary apolipoprotein H (Apo H), otherwise known as beta 2-glycoprotein I, we first developed a non-competitive enzyme immunoassay (EIA) to quantify urinary Apo H levels. The measurable range of this assay was about 2 ng/ml to 100 ng/ml. The intra- and inter-assay coefficients of variation were 2.0 to 4.7% and 8.3 to 17.0%, respectively. These results indicated that this assay had high sensitivity and good reproducibility, and that it was useful for clinical study. We then determined urinary Apo H levels in 24 normal subjects and 36 diabetics using this assay. The mean urinary Apo H index (urinary Apo H/cr ratio), in 20 patients without proteinuria, who were regarded as patients without nephropathy, was 569 +/- 560 (X10(-3) mg/g.cr) and significantly higher than in normal subjects (252 +/- 147, p less than 0.01). The mean urinary Apo H index in 16 patients with overt proteinuria was 1,507 +/- 3,701 and also higher than in normal subjects (p less than 0.01). These results taken collectively indicate that urinary Apo H level using the EIA may be a new sensitive marker for detecting minor change of glomerular basement membrane in diabetics.

Adult↗
PubMed1991

A case of acquired nystagmus alternans associated with acute cerebellitis.

A case of acquired nystagmus alternans (alternating nystagmus) is reported. The patient was a 14-year-old boy who presented with fever and headache, followed by dysbasia, truncal ataxia, and positional vertigo. Neuro-otological examinations revealed spontaneous downbeat nystagmus, bilateral gaze nystagmus and rebound nystagmus. Both cell count and protein volume were elevated in the cerebrospinal fluid, and a diagnosis of cerebellitis was made. About one month later, nystagmus alternans was observed, but it disappeared after 7 months. The presence of spontaneous downbeat nystagmus, rebound nystagmus, as well as cerebellar signs indicated that a cerebellar lesion was mainly responsible for the nystagmus alternans in this patient.

Acute Disease↗
PubMed1990

Cancer risk among children of atomic bomb survivors. A review of RERF epidemiologic studies. Radiation Effects Research Foundation.

This article summarizes recent epidemiologic studies of cancer risk among the children of atomic bomb survivors conducted at the Radiation Effects Research Foundation. These children include two groups: (1) the in utero-exposed children (ie, those born to mothers who had been pregnant at the time of the bombings of Hiroshima and Nagasaki) and (2) the F1 population, which was conceived after the atomic-bombings and born to parents of whom one or both were atomic bomb survivors. Although from 1950 to 1984 only 18 cancer cases were identified among the in utero sample, cancer risk did appear to significantly increase as maternal uterine dose increased. However, since the observed cases are too few in number to allow a site-specific review, the increased cancer risk cannot be definitively attributed to atomic bomb radiation, as yet. For those members of the F1 population who were less than 20 years old between 1946 and 1982, cancer risk did not appear to increase significantly as parental gonadal dose increased. Follow-up of this population will continue to determine if the patterns of adult-onset cancer are altered.

Abnormalities, Radiation-Induced↗
PubMed1990

Cortical alveolus breakdown in the eggs of the freshwater teleost Rhodeus ocellatus ocellatus.

Cortical alveoli and their breakdown in the eggs of the rose bitterling were morphologically investigated. Cortical alveoli of various sizes existed in multiple layers within the cortical cytoplasm of each egg. Two types of cortical alveoli were recognized--one possessed homogeneous contents; the other possessed heterogeneous contents with electron-less dense spots. The eggs were activated by a penetrating spermatozoon or by immersion in fresh water. The immersion of the eggs into fresh water induced a wave of cortical alveolus breakdown (CABD), which was propagated from the vegetal pole to the animal pole. When eggs were inseminated in fresh water, CABD progressed from both the vegetal and the animal poles of the egg, and was complete within about 20 min. The contents of the cortical alveoli were released into the perivitelline space through a large opening formed by the fusion of the plasma and cortical alveolar membranes. For a short time after CABD, the smooth inner surfaces of the cortical alveoli were readily discernible from the rougher original plasma membrane. About 30 min after immersion in fresh water, the inner surfaces of the cortical alveoli were indistinguishable from the original egg surfaces. Aequorin-injected eggs became luminescent immediately after their immersion in fresh water. The luminescence reached a maximum level about 15 min later and subsided after roughly 30 min. The result shows that increase in intracellular free Ca ions occurs during CABD.

Aequorin↗