Biomedical subjects

T Yoshihara

Publications and source records attributed to T Yoshihara.

At least 109 records · Page 6Linked to original sources

PubMed1995

Fibrous hamartoma of the tongue: report of a case with immunohistochemical and ultrastructural studies.

The case of an 8-month-old female with fibrous hamartoma of the tongue is reported with immunohistochemical and electron microscopic findings. An elastic hard mass at the base of the tongue gradually enlarged, causing dysphagia. The tumor was excised by CO2 laser. Under light microscopy, the tumor was observed as composed of fibroblast-like cells, fibrocollagenous bundles and striated muscle tissues. The majority of the cells were immunoreactive for vimentin. Electronmicroscopically, they contained numerous intermediate filaments, some had intercellular microvilli and cilia (9 + 2 type). These findings revealed that the cells of the fibrous hamartoma in our case may possess both mesenchymal and epithelial properties.

Female↗

PubMed1995

Carcinoma ex pleomorphic adenoma of the soft palate.

A case of carcinoma ex pleomorphic adenoma arising in the soft palate is reported. The tumour presented had enlarged gradually over 10 years and finally occupied the oral cavity. The patient was admitted to our hospital due to disturbance of her speech and swallowing, and a sudden haemorrhage from the tumour. The initial pathological diagnosis by open biopsy was benign pleomorphic adenoma. After total resection, histological examination revealed that the tumour was composed partly of benign pleomorphic adenoma and partly of an adenocarcinomatous component. The carcinoma cells with prominent nucleoli were spheroid or polygonal in shape, and frequently formed ductal structures with areas of necrosis. Mitoses were also found. These findings showed that this tumour was a secondary carcinoma which had developed in a preexisting pleomorphic adenoma.

Adenocarcinoma↗

PubMed1995

Nasal natural killer (NK) cell lymphoma: report of a case with activated NK cells containing Epstein-Barr virus and expressing CD21 antigen, and comparative studies of their phenotype and cytotoxicity with normal NK cells.

Malignant lymphomas arising from the nasal cavity have been considered to be derived from T cells, but recent surface marker studies suggest that more than half of the lymphomas are derived from natural killer (NK) cells. Here we describe a case of nasal lymphoma whose lymphoma cells were identified as NK cells by morphological, phenotypic, immunogenotypic, and functional studies. We believe this is the first study with functional evidence of NK activity. When compared with normal freshly isolated NK cells or activated NK cells, the surface phenotypes and NK activity of the patient tumour cells were those of the activated, but not resting, NK cells. Also, Epstein-Barr virus (EBV) was detected in the tumour cells and the lymphoma cells were found to be monoclonally expanded. The patient's lymphoma cells also expressed EBV receptor CD21 (CR2) and CD30 (Ki-1) that have not been described on normal NK cells. We therefore examined highly enriched NK cells of normal donors, and found that some resting and/or activated NK cells express these antigens.

Antigens, CD↗

PubMed1995

Myelodysplasia and acute myeloid leukaemia in cases of aplastic anaemia and congenital neutropenia following G-CSF administration.

Myelodysplasia and acute myeloid leukaemia (MDS/AML) developed in three cases of severe aplastic anaemia (SAA) and one case of congenital neutropenia (CN, Kostmann's disease) who received recombinant human granulocyte colony-stimulating factor (G-CSF) are reported. In these four MDS/AML cases, age at diagnosis of SAA/CN was 0-13 years, the cumulative dose of G-CSF was 98 micrograms/kg to 10 mg/kg over 1-57 months, and the interval from initiation of G-CSF to MDS/AML was 25, 23, 31 and 57 months, respectively. These results suggest a link between SAA/CN and MDS/AML in relation to G-CSF administration; however, large studies are necessary to determine if such a risk is significant in patients with SAA/CN who are treated with G-CSF.

Adolescent↗

PubMed1995

Age-related morphometrical changes of arteries of uterine wall in mares.

To investigate the morphological changes of uterine wall arteries associated with the progression of age in Thoroughbred broodmares, uterine wall arteries from 13 mares, aged 2 to 31 years, were studied by routine histomorphometry. The ratio of intimal thickness to external diameter increased due to hyperplasia of elastic fibers and was significantly correlated with age (r = 0.95, P < 0.001). The ratio of medial thickness to external diameter decreased and was also significantly correlated with age (r = -0.84, P < 0.001). Using electron microscopy, it was determined that the cross-sectional area of the tunica media occupied by smooth muscle cells gradually decreased with increasing age. These results demonstrate that in arteries of the uterine wall in mares, hyperplasia of intimal elastic fiber and thinning of the medial smooth muscular layer is associated with aging, suggesting that aging may influence endometrial pathology.

Aging↗

PubMed1995

E2A-HLF-mediated cell transformation requires both the trans-activation domains of E2A and the leucine zipper dimerization domain of HLF.

The E2A-HLF fusion gene, formed by the t(17;19)(q22;p13) translocation in childhood acute pro-B-cell leukemia, encodes a hybrid protein that contains the paired trans-activation domains of E2A (E12/E47) linked to the basic region/leucine zipper DNA-binding and dimerization domain of hepatic leukemia factor (HLF). To assess the transforming potential of this novel gene, we introduced it into NIH 3T3 murine fibroblasts by using an expression vector that also contained the neomycin resistance gene. Cells selected for resistance to the neomycin analog G418 formed aberrant colonies in monolayer cultures, marked by increased cell density and altered morphology. Transfected cells also grew readily in soft agar, producing colonies whose sizes correlated with E2A-HLF expression levels. Subclones expanded from colonies with high levels of the protein reproducibly formed tumors in nude mice and grew to higher plateau-phase cell densities in reduced-serum conditions than did parental NIH 3T3 cells. By contrast, NIH 3T3 cells expressing mutant E2A-HLF proteins that lacked either of the bipartite E2A trans-activation domains or the HLF leucine zipper domain failed to show oncogenic properties, including anchorage-independent cell growth. Thus, both of the E2A trans-activation motifs and the HLF leucine zipper dimerization domain are essential for the transforming potential of the chimeric E2A-HLF protein, suggesting a model in which aberrant regulation of the expression pattern of downstream target genes contributes to leukemogenesis.

3T3 Cells↗

PubMed1995

[Neurilemmoma of intra-temporal facial nerve:case report].

A case of facial nerve neurilemmoma within the temporal bone is reported. The patient is a 47-year-old female complaining of 10 years' history of left facial palsy. CT and MRI examinations showed an enlarged mass of the tympanic cavity protruding into the petrous bone, mastoid cavity and external auditory meatus. An open biopsy of the tumor at the external auditory meatus revealed neurilemmoma. The tumor was totally removed by a retroauricular approach. Five months after surgery, both the cross nerve graft using the peroneal nerve and the temporal muscle transfer, method modified by Johnson were performed for the functional recovery of facial palsy.

Cranial Nerve Neoplasms↗

PubMed1995

[A neuroendocrinological study on the mechanism of feeding-associated circadian rhythm of plasma corticosterone and feeding behaviour in rats: a role of neuropeptide Y in the paraventricular nucleus].

Plasma corticosterone (CORT) level in rats increases before meal (pre-feeding peak), when rats are subjected to restricted daily feeding (RF), in which food is supplied only at a fixed time of day. Corticotropin-releasing hormones (CRH) release is also suggested to increase prior to meal. Cell bodies of CRH neurons exist in the paraventricular nucleus (PVN) which receives neuropeptide Y (NPY) containing neurons of two different origins: one from the brainstem, in which catecholamine (CA) coexists, and the other from the arcuate nucleus (ARC). The aim of the present study is to examine the role of NPY neurons from the brainstem in feeding and CRH secretion. To accomplish this aim, NPY in the discrete areas of brain and in the extracellular space of the PVN were measured under ad-lib feeding, food deprivation, and RF, together with plasma CORT level. Under ad-lib feeding, NPY in the PVN didn't variate throughout the day. The extracellular NPY in the PVN, however, increased under food deprivation, which decreased rapidly after refeeding, and increased just before the daily meal under RF. And this preprandial increase reappeared by 3 day food deprivation even after RF was terminated and replaced by ad-lib feeding for 7 days. The preprandial increase was suppressed by 6-hydroxy-dopamine (6-OHDA), a CA deprivator, injected into the PVN or the ascending bundle of noradrenaline fibers. It is concluded that, (1) the NPY neurons in the PVN aren't involved in the regulation of plasma CORT level and feeding behavior under ad-lib feeding, but involved under food deprivation, (2) the prefeeding increase of the extracellular NPY in the PVN is an expression of a feeding-associated circadian oscillation under RF. By contrast, the prandial decrease in the extracellular NPY is a result of food intake, (3) the noradrenergic neurons innervating the PVN are important for the expression of the prefeeding NPY peak under RF.

Animals↗

PubMed1995

Acinic cell tumour of the maxillary sinus: an unusual case initially diagnosed as parotid cancer.

An unusual case of acinic cell tumour of the maxillary sinus is presented. The patient, a 41-year-old male who had undergone incomplete excision of the tumour in the left parotid region previously, was referred to our department for further treatment. The initial pathological diagnosis was adenocarcinoma of the parotid gland. CT-scan not only revealed tumours in the left pre-auricular and upper neck region, but also an enhanced mass in the left maxillary sinus. Although there were neither nasal symptoms nor destruction of the maxillary bone, aspiration biopsy of the maxillary sinus revealed class V. Total maxillectomy, radiotherapy and systemic chemotherapy were performed just after total parotidectomy and radical neck dissection at the left side. The clinical and histopathological findings are discussed.

Adenocarcinoma↗

PubMed1994

Jasmonate-inducible expression of a potato cathepsin D inhibitor-GUS gene fusion in tobacco cells.

A potato gene encoding cathepsin D inhibitor (CDI) is expressed constitutively in tubers and flower buds and it is inducible in leaves upon wounding of the tissue or by treatment with methyl jasmonate (MJA). A fusion gene (CDI:GUS) in which the 2.4 kb long promoter of the CDI gene was translationaly fused with the coding sequence for beta-glucuronidase (GUS) showed MJA-inducible expression in transformed tobacco cells in suspension. The maximum level of induction by MJA was obtained in the absence of auxin and repression of MJA-inducible expression of the fusion gene by auxin was released by aphidicolin, the results suggesting that MJA-inducible expression is repressed during active cell division. JA and MJA showed similar activities in inducing the expression of the fusion gene, while other JA-related compounds such as cucurbic acid, tuberonic acid and dihydrojasmonic acid neither induced expression of the fusion gene nor inhibited the MJA-inducible expression of the fusion gene. Methyl dihydrojasmonate specifically stimulated the MJA-inducible expression of the fusion gene. The MJA-inducible expression of the fusion gene was observed even with a 100 bp long promoter of the CDI gene albeit with significantly decreased level of expression compared to the 2.4 kb long promoter. The 100 bp long CDI promoter did not contain a G-box or hexamer motif that had been implicated in the MJA-responsive expression of several other plant genes. Further mutagenesis of the 100 bp long promoter by deletion or oligonucleotide insertion suggested that although a sequence between -100 and -82 is required for the MJA-responsive expression, the presence of this sequence alone does not confer the MJA-responsive expression.

2,4-Dichlorophenoxyacetic Acid↗

PubMed1994

Embryonal rhabdomyosarcoma arising in the buccal mucosa: a case report with immunohistochemical and electronmicroscopic findings.

Rhabdomyosarcoma is one of the most common soft-tissue neoplasms in children. We report a case of a 9-year-old female with embryonal rhabdomyosarcoma arising in the buccal region with immunohistochemical and electronmicroscopic findings. Under a light microscope, it was observed that the tumor was composed of small round or spindle-shaped cells with pleomorphic and hyperchromatic nuclei. They were immunoreactive for actin, myoglobin and desmin. With an electron microscope, it was found that most tumor cells contained filamentous structures and free ribosomes. Some of them showed typical myofilaments, M-bands and Z-lines. These findings were specific evidence of rhabdomyosarcoma. Twenty courses of VAC (vincristine, D-actinomycin and cyclophosphamide) chemotherapy were administered, followed by surgical resection of the tumor.

Actins↗

PubMed1994

Cervical neurofibroma in a patient with von Recklinghausen's disease.

A case of a huge cervical neurofibroma associated with von Recklinghausen's disease is reported. The patient with von Recklinghausen's disease was a 48-year-old woman complaining of a rapidly growing mass around the neck for the last 6 months. In von Recklinghausen's disease, which corresponds to neurofibromatosis-I, gigantic tumors around the neck often occur. The present case was classified as a plexiform neurofibroma which is derived from the peripheral nervous system, and this type frequently shows malignant change in contrast to other types of neurofibroma. In general, it is difficult to determine the origin of the nerve in cervical neurofibromas. A total extirpation of the tumor was done in our case, and revealed the nerve of origin to be the vagal nerve. Pathologically, H-E stained specimens showed that the tumor was a benign neurofibroma. However, immunostaining of the majority of the tumor cells were positive for PCNA. These results suggest that the tumor of our case possessed a low malignant potential. To date, neither local recurrence nor distant metastasis has been found on subsequent examinations.

Cranial Nerve Neoplasms↗

PubMed1994

Preparation and characterization of monoclonal antibodies against equine chondrocytes, osteoblasts and osteocytes.

Three monoclonal antibodies capable of individually recognizing chondrocytes, osteoblasts and osteocytes were prepared. EB-1 reacted with a 55-kDa antigen on the chondrocyte membrane, EB-2 with a 110-kDa antigen on the membrane of osteoblasts and/or partial osteocytes, and EB-3 with a 130-kDa antigen on the membrane of osteocytes. These monoclonal antibodies may be useful probes for studying the differentiation and maturation of osteogenic cells.

Animals↗

PubMed1994

Prefeeding increase in paraventricular NE release is regulated by a feeding-associated rhythm in rats.

Extracellular norepinephrine (NE) in the vicinity of the paraventricular nucleus was continuously measured over 24 h by means of in vivo microdialysis in rats under restricted daily feeding and ad libitum feeding. A 24-h rhythm in plasma corticosterone was monitored in separate rats under identical conditions. Under ad libitum feeding, the paraventricular NE showed a 24-h rhythm with lower levels in the light period and higher levels in the dark period. The temporal pattern was not affected by food deprivation for 3 days. The circadian peak of paraventricular NE lagged slightly behind that of plasma corticosterone under ad libitum feeding. On the other hand, when rats were fed for 2 h at a fixed time of day for 3 wk, the NE rhythm was changed and showed a major peak just before daily meals. To examine the nature of the prefeeding NE peak, a 24-hour variation of paraventricular NE was measured in rats under food deprivation that had been subjected to restricted daily feeding for 3 wk and subsequently to ad libitum feeding for 7 days. The paraventricular NE was high around the time when meal had been supplied under restricted daily feeding and low in the dark period. Similar changes were observed in plasma corticosterone. The findings indicate that the prefeeding increase in the paraventricular NE release is regulated by a feeding-associated circadian rhythm manifest in rats under restricted daily feeding.

Animals↗

PubMed1994

Effect of gentamycin on vestibular dark cells and melanocytes: an ultrastructural and cytochemical study.

Vestibular dark cells areas in gentamycin (GM)-intoxicated guinea pigs were examined ultrastructurally and cytochemically. After GM treatment the dark cells represented cytoplasmic vacuoles, wide intercellular space, less osmiophilic cytoplasm and irregularly shaped basal portions. Cytochemically, Na+,K(+)-ATPase activity was demonstrated on the basolateral folded plasma membranes of the dark cells similarly in both GM-intoxicated and control guinea pigs. These findings revealed that the dark cells still possessed a function of regulating the ionic composition of the endolymph, although they showed various structural changes. On the other hand, the melanocytes extended their cytoplasmic processes into the basement membrane and the intercellular space of the dark cells. Melanosomes markedly increased in number dose-dependently by GM treatment. The significance and the function of the melanocytes in the dark-cell areas are discussed.

Animals↗

PubMed1994

Ultrastructural and immunocytochemical study of the subepithelial fiber component of the guinea pig inner ear.

The connective tissues of the lateral cochlear wall and semicircular canal of the guinea pig were investigated by transmission electron microscopy, intermediate voltage electron microscopy and immunocytochemistry. In the spiral ligament, numerous fibroblasts and fiber bundles were intermingled with each other. Fibroblasts and fibers were also observed in the semicircular canal. Ultrastructurally, immuno-gold particles, indicating the presence of type II collagen, were found on the fibers in the spiral ligament and the semicircular canals. The present results revealed that both stria vascularis and the membranous semicircular canal were supported by a network of fibroblasts and type II collagen fibers.

Animals↗

PubMed1994

[Nasal NK-cell lymphoma].

A 75-year-old man was admitted to our hospital on June 1st, 1993, because of nasal obstruction, epistaxis, fever, night sweats and weight loss. Examination disclosed a 2-cm white necrotic mass in the nasal septum, and a biopsy disclosed non-Hodgkin's lymphoma, diffuse, mixed-type. Imprint smears showed cytoplasmic azurophilic granules in the tumor cells. Dense granules were demonstrated by electron microscopy. The tumor cells were CD1-2+3-4-7+8-16+56+57-, and T cell receptor genes were in germline configuration. NK activity against K562 was strongly positive. Based on morphologic, phenotypic, immunogenotypic, and cytotoxic findings, the tumor cells seemed to be derived from activated NK cells. Because the tumor cells were positive for the EB virus and CD21 antigen, EB virus seemed to have infected CD21-positive NK cells and transformed them. MDR P-glycoprotein was also positive. This finding may explain why nasal lymphomas are resistant to chemotherapy and have a poor prognosis.

Cell Transformation, Viral↗

PubMed1993

Microscopical characteristics of uterine wall arteries in barren aged mares.

The morphology of the arteries in the uterine wall was studied in three multiparous aged mares that had suffered repeated pregnancy failure. The uterine wall arteries exhibited elastosis of the intima or adventitia, or both, resembling "physiological pregnancy sclerosis". In areas affected by elastosis, degeneration of the pre-existing elastic fibres and increased glycosaminoglycans were frequently observed. Newly formed elastic fibres were not evident. Delayed resorption due to disordered metabolic turnover of the elastin was thought to be an important factor in the pathogenesis of the arterial elastosis in the uterine wall.

Aging↗