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Biomedical subjects

A Tamada

Publications and source records attributed to A Tamada.

At least 55 records · Page 3Linked to original sources
PubMed1993

Ultrastructure of the parathyroid gland of magnesium-treated golden hamster exposed to a hypergravity environment: a stereological study.

The ultrastructure of the parathyroid glands of magnesium-treated golden hamsters exposed to a 5 gravity environment was studied. In the parathyroid glands of the magnesium-treated animals exposed to a hypergravity environment, the Golgi complexes and cisternae of the granular endoplasmic reticulum were increased as compared to those of the magnesium-treated animals and decreased as compared to those of animals exposed to a hypergravity environment, but were almost the same as those of the control animals. In the control and experimental animals, the chief cells were rich in free ribosomes and mitochondria. In addition, numerous secretory granules were situated close to the plasma membrane in the magnesium-treated animals exposed to a hypergravity environment. These observations suggest that the synthesis of parathyroid hormone may be stimulated in the parathyroid glands of magnesium-treated hamsters exposed to hypergravity environment.

Animals↗
PubMed1992

Effects of short-term treatment with calcium on the parathyroid glands in golden hamsters of different ages, with special reference to large vacuolar bodies.

The effects of different ages on large vacuolar bodies in the parathyroid glands of golden hamsters after short-term treatment with calcium were investigated. In the parathyroid glands of the young and adult animals 15 min and the senile animals 15 and 60 min after administration of calcium, the percent area occupied by large vacuolar bodies was significantly increased as compared to that of the young, adult and senile control animals, respectively. These findings suggest that the percent area occupied by large vacuolar bodies is increased in response to acute hypercalcemia. It is thought that in the parathyroid glands suppressed by hypercalcemia there is a relationship between the percent area occupied by large vacuolar bodies and aging.

Aging↗
PubMed1992

Stereological studies of the parathyroid gland of phosphate-treated golden hamsters subjected to a hypergravity environment.

The ultrastructure of the parathyroid glands of phosphate-treated golden hamsters exposed to a 5-G environment was studied. In the phosphate-treated animals exposed to a hypergravity environment, the Golgi complexes associated with numerous prosecretory granules, and the enlarged intercellular spaces containing floccular or finely particulate material showed a significant increase compared to those of the control, centrifuged, and phosphate-treated groups, and the cisternae of the granular endoplasmic reticulum showed a significant increase compared to those of the control and phosphate-treated groups. In addition, numerous secretory granules were situated close to the plasma membrane of chief cells in the phosphate-treated animals exposed to a hypergravity environment. These findings suggest that the synthesis, and to a greater extent the release of secretory granules may be markedly stimulated, in the parathyroid glands of phosphate-treated animals exposed to a hypergravity environment.

Animals↗
PubMed1992

Ultrastructure of the parathyroid gland of fetal and pregnant golden hamsters subjected to hypergravity environment.

The ultrastructure of the parathyroid glands of fetal and pregnant golden hamsters exposed to 5-gravity environment was studied. In the centrifuged fetal animals the Golgi complexes associated with some prosecretory granules were significantly increased compared with those of the control fetal animals, and several secretory granules were located in a peripheral position just beneath the plasma membrane. In the centrifuged pregnant animals the Golgi complexes associated with numerous prosecretory granules were significantly increased, cisternae of the granular endoplasmic reticulum appeared to be increased compared with those of the control pregnant animals, many secretory granules were located in the peripheral cytoplasm and several granules were situated close to the plasma membrane. These findings suggest that in the parathyroid glands of the fetal golden hamsters as well as the pregnant animals the synthesis and release of parathyroid hormone may be stimulated in response to a hypergravity environment.

Animals↗
PubMed1992

Effects of hypergravity environment on the parathyroid gland of the norepinephrine-treated golden hamster: a stereological study.

Effects of 5-gravity environment on the ultrastructure of the parathyroid glands of norepinephrine-treated golden hamsters were studied. In the centrifuged animals treated with norepinephrine, the volume density occupied by the Golgi complexes associated with numerous prosecretory granules was significantly increased compared with that of the control, centrifuged and norepinephrine-treated animals, as well as the volume density occupied by the cisternae of the granular endoplasmic reticulum compared with that of the control and centrifuged animals. In addition, in the centrifuged animals treated with norepinephrine, numerous secretory granules were situated close to the plasma membrane. It is suggested that the synthesis and release of secretory granules may be markedly stimulated in the parathyroid glands of the norepinephrine-treated golden hamsters subjected to a hypergravity environment.

Adrenergic alpha-Agonists↗
PubMed1992

An in vitro study on the effects of melatonin on the ultrastructure of the hamster parathyroid gland.

Isolated parathyroid glands from adult female golden hamsters were incubated on a black Millipore filter in an incubation vessel containing Ham's F-12 medium, with or without melatonin at final concentration of 10(-5) M for 1 hour. In the parathyroid glands used for in vitro treatments with melatonin, the Golgi complexes associated with a few prosecretory granules and cisternae of the rough endoplasmic reticulum showed a significant decrease, and lipid droplets and lysosomes appeared to be increased compared with those of the control parathyroid glands. These changes are considered to be induced by suppression of the synthesis of parathyroid hormone in parathyroid glands incubated in a vessel containing medium with melatonin.

Animals↗
PubMed1992

[Two cases of the horseshoe kidney].

The present report is concerned with two cases of the horseshoe kidney. During the dissecting practice at Gifu University School of Medicine in 1991, the case 1 was found in a female Japanese cadaver of 84 years old and the case 2 in a female Japanese cadaver of 84 years old and the case 2 in a female Japanese cadaver of 85 years old. 1) In both cases, the two kidneys were united at their lower ends across the midline of the body. The part of fusion called the isthmus consisted of renal tissues. 2) In both the cases 1 and 2, the hilus of each kidney opened anteriorly, and the ureters passed in front of the isthmus and entered the urinary bladder normally. The location of each kidney was lower than that of the normal kidney. 3) Surplus arteries arising from the abdominal aorta were observed in the cases 1 and 2. In the case 1, one surplus artery entered the left kidney and the isthmus. In the case 2, five surplus arteries were observed; two arteries entered the right kidney, one the left kidney and two the isthmus. 4) The incidence of the horseshoe kidney during the dissecting practice at Gifu University School of Medicine from 1971 to 1991 was 0.33% (three out of 908 bodies). 5) In both the cases 1 and 2, no malformation was observed in other organs.

Aged↗
PubMed1991

Lesion-induced establishment of the crossed corticorubral projections in kittens is associated with axonal proliferation and topographic refinement.

The aberrant crossed corticorubral projection of the cat, which is very weak compared to the uncrossed one at about 1 month postnatal, becomes pronounced following unilateral lesions of the sensorimotor cortex. In order to determine whether or not terminal proliferation of pre-existing axons underlie this enlargement, the morphological changes of the crossed axons were examined, using the anterograde tracer Phaseolus vulgar- is leukoagglutinin (PHA-L). The crossed corticorubral axons in normal kittens were mostly simple in morphology with infrequent branching and did not often exhibit growth-cone-like axonal endings at 1 month postnatal. Two to 5 days after unilateral lesions of the sensorimotor cortex placed at this age, the axons were as simple as those in normal animals but ended in growth cones more frequently. Seven to 10 days post-lesion, the axons often bore side-branches which ended in growth cones. Two to 3 weeks post-lesion axons with sprays of finger-like fine sprouts occurred throughout the projection zone. There was no clear topography for the crossed projection in normal animals, but at 1-2 weeks post-lesion the axons started to show a certain amount of localization in the regions of the red nucleus which corresponded to the densely innervated region on the ipsilateral side. The topography of the crossed projections roughly mirrors that of the ipsilateral projection at about 1 month post-lesion. Thus, the lesions of the sensorimotor cortex induce substantial growth and proliferation of the crossed corticorubral axons. The post-lesion changes in axonal morphology and topographic refinement are reminiscent of developmental events. It is likely that the lesions permit the crossed axons, which normally fail to develop, to develop like the uncrossed ones.

Aging↗
PubMed1991

Electron-microscopic study of the parathyroid gland of epinephrine-treated golden hamsters subjected to hypergravity environment.

The ultrastructure of the parathyroid glands of golden hamsters subjected to 5-gravity environment after administration of epinephrine was studied. In the epinephrine-treated animals exposed to a hypergravity environment, the Golgi complexes associated with numerous prosecretory granules were significantly increased compared with those of the control, centrifuged and epinephrine-treated animals, as well as the cisternae of the granular endoplasmic reticulum compared with those of the control and centrifuged animals. In addition, many secretory granules were situated close to the the plasma membrane of the chief cells in the epinephrine-treated animals exposed to a hypergravity environment. Those observations suggest that the secretory activity of the parathyroid gland may be markedly stimulated in the epinephrine-treated animals exposed to a hypergravity environment.

Animals↗
PubMed1988

An analysis of postsynaptic potentials of tectal neurons of the frog: correlation with impulses recorded from the terminals of retinotectal afferents.

The purpose of this study is to examine the synaptic action between terminals of retinal ganglion cell axons and tectal neurons. To accomplish this, an extracellular single unit identified as retinotectal fiber was first isolated from the superficial layer of the optic tectum and intracellular responses were recorded from a tectal neuron in the vicinity of the extracellular recording electrode. "On-off" retinal fibers and both E-E (EPSP at "on" and "off" of diffuse light) and EI-EI type (EPSP-IPSP combination at "on" and "off" of diffuse light) tectal neurons were selected for the pre- and postsynaptic pair. Postsynaptic responses to a small moving square were averaged by triggering with the isolated presynaptic impulses. The latency of the resultant EPSPs indicated that most of the E-E and EI-EI type tectal neurons were monosynaptically activated by "on-off" retinal fibers. One of the E-E type tectal neurons was identified as a large ganglionic neuron in layer 8.

Action Potentials↗
PubMed1984

Titers of Epstein-Barr virus-related antibodies in nasopharyngeal carcinoma in Japan.

It is thought that nonkeratinizing or undifferentiated squamous cell carcinoma in the nasopharynx (NPC) is intimately correlated with Epstein-Barr Virus (EBV). Twenty-one patients with NPC were followed in Kyoto University Hospital and 4 in Osaka Red Cross Hospital during the past 2 years from 1980 to 1981. These patients were classified histopathologically according to the WHO classification in 1978 and staged with the TNM classification in Union Internationale Contre le Cancer (UICC) in 1978. The incidence rate of NPC among the head and neck tumors was 5.6% in the authors' university from 1980 to 1981. The sex ratio of male to female was nearly equal. The mean age of NPC patients was 56.7 years. Sera from these 25 patients with nasopharyngeal carcinoma were collected at intervals of 3 to 8 months over a 2-year period, and were examined for their spectra and titers of antibodies of EBV-related antigens. They were titrated for IgG, IgA and IgM antibodies to EB viral capsid antigen (VCA), for IgG and IgA antibodies to early antigen-DR component (EA) and for antibodies to EBV-associated nuclear antigen (EBNA). All of these patients were primarily treated with radiation, while a few who did not respond to this therapy were subsequently treated with surgery or chemotherapy. EBV antibodies of VCA-IgG, -IgA, EA(DR)-IgG, and -IgA and EBNA were elevated in 73% and 90% of the nonkeratinizing and undifferentiated NPC patients, respectively. The VCA-IgM was elevated in almost none of the cases. In contrast to this, these values were all in a normal range in the NPC patients with keratinizing squamous cell carcinoma and malignant lymphoma. Also 9% and 10% of nonkeratinizing and undifferentiated carcinomas showed the normal ranges of EBV antibodies, possibly indicating a nonassociation with EBV. When NPC disappeared with radiation therapy, EBV antibodies became normal for 6-18 months. However, those whose NPC did not respond to the combined therapy with radiation, surgery and chemotherapy maintained high titers of EBV antibodies. The prognosis was the poorest in the patients with undifferentiated carcinoma, 40% of whom died within 4 years after diagnosis.

Adult↗
PubMed1984

Radiation-induced fibrosarcoma of the thyroid.

A rare thyroid tumour is described. It started as a papillary cytoadenoma 20 years ago, followed by the appearance of a papillary adenocarcinoma 6 years later. At that time most of the tumour was excised, except for a small portion which had invaded the trachea. Post-operatively 6,000 rads of Co60 was given to the neck; the tumour remained quiescent for 18 years until two years ago, when a recurring fibrosarcoma appeared in her neck. It is suggested that this tumour was a radiation-induced sarcoma.

Carcinoma, Papillary↗
PubMed1984

Olfactory neuroblastoma: presentation of a case and review of the Japanese literature.

Olfactory neuroblastoma is an uncommon malignant tumor arising from the nasal cavity. During the past 18 years from 1964 to 1982, only 24 cases have been in Japanese literature, including this case. The average age of these patients is 42.3 years, ranging from 4 to 75 years old. The sex ratio of male to female is 10:14, female being prevalent moderately. The peak distribution is from 30 to 40 years old. The majority of the patients died of distant metastasis within 2 years of diagnosis. Therefore, the overall prognosis in Japan is very poor, as compared with about a 50% 5 year survival rate in the western countries. This is probably because this tumor is difficult to diagnose correctly, and the chance to start treatment early is apt to be missed here, though some tumors behaved very aggressively from the beginning, metastasizing early.

Adolescent↗
PubMed1984

Combined scintiscans in the diagnosis of thyroid carcinomas.

We correlated scintigraphy and histological findings in 40 cases of nodular goiter in which two or more kinds of scintigraphy were performed preoperatively. 201Tl scintigraphy for imaging thyroid carcinoma showed a diagnostic agreement of 80% for thyroid lesions and 82% for metastatic lesions in the cervical lymph nodes. These agreements were higher than with 99mTc-bleomycin scintigraphy. Thus, 201Tl scan can be used to evaluate 'cold' thyroid nodules and to visualize metastatic lesions. 201Tl scan was also found valuable as a diagnostic measure for local recurrence of thyroid carcinoma. However, there were a few false-positive and false-negative results.

Adenoma↗
PubMed1983

Observations on immunologic parameters in laryngeal cancer patients.

Patients with laryngeal cancer were examined immunologically before treatment and for 1-10 years after treatment. In the pretreatment group, the percentage of T cells, lymphocyte blastoid reaction (PHA, concanavalin A), and skin reactions (PHA) were generally in the normal range, but absolute numbers of T cells and lymphocytes were reduced in most patients. In the group with no recurrence after surgery, the absolute number of T cells and lymphocytes, IgG X FcR+T cells (T gamma), and skin reactions was normal in many cases. The group with recurrence showed reduced percentage of T cells and an absolute number of T cells and lymphocytes. The absolute number of T cells and lymphocytes and the PPD skin reaction increased after surgery in some cases, but reductions in some of the parameters were noted in a few cases long after surgery. Radiation therapy for patients with tumors at early stages did not significantly change the percentage of T cells or the skin reactions.

Aged↗