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Biomedical subjects

T Hirakawa

Publications and source records attributed to T Hirakawa.

At least 19 recordsLinked to original sources
PubMed1992

Tactile and taste sensory maturation of the frog larvae tongue.

The maturation process of organs in the oral cavity of the larvae of bullfrogs, Rana catesbeiana, corresponding to the larval stages XVIII to XXV distinguished by Taylor and Kallros Anat. Rec., 94 (1946) 7-25, were investigated. In this study, these larval stages were divided by the width of the mouth slit into A1, A2, B and C stages. The A1 and A2 stages corresponded to larval stages XVIII-XIX and XX, respectively. The B and C stages corresponded to stages XXI and XXII-XXV, respectively. In stage A1, mechanical and chemical stimulation of the tongue rudiment, in most larvae, failed to elicit afferent discharges in glossopharyngeal nerves. However, in a small number of larvae, obvious afferent discharges of these nerves were generated. In stage A2, glossopharyngeal nerves in most larvae began responding to the same stimulations. The amplitude increased with decreasing duration of afferent discharges, resembling those of the adult. In stage B, the first glossopharyngeal-hypoglossal nerve reflex (G-H reflex) was elicited by mechanical stimulation of the tongue. In stage C, the G-H reflex was also induced by chemical stimulation and the latency of the G-H reflex elicited by mechanical stimulation decreased. In this stage, expansion and extension of the tongue increased. Therefore, the natural function of this reflex for the intake of food may follow this stage.

Animals↗
PubMed1992

Reactive oxygen-reducing and protein-refolding activities of adult T cell leukemia-derived factor/human thioredoxin.

Reducing and protein-refolding activities of adult T cell leukemia-derived factor (ADF)/human thioredoxin were studied. Recombinant ADF/human thioredoxin produced by E. coli, which has an insulin-reducing activity as efficient as that of E. coli thioredoxin, also reduced some reactive oxygen species, such as hydrogen peroxide. Furthermore, recombinant ADF/human thioredoxin was found to have protein-refolding activity for scrambled (mispaired disulfide-containing) RNase A. Cys-31 at the active site of ADF/human thioredoxin proved essential for reducing activity, and loss of Cys-31 in ADF/human thioredoxin attenuated the protein-refolding activity. These data suggest a physiological role of ADF/human thioredoxin in protecting living cells from proteotoxicity caused by reactive oxygens in vivo.

Amino Acid Sequence↗
PubMed1991

Massive accumulation of neutral lipids in cells conditionally transformed by an activated H-ras oncogene.

Phenotypic consequences of ras oncogene expression were studied in cells conditionally transformed by T24 H-ras and a temperature-sensitive SV40 large T antigen (tsA58). Previous studies have demonstrated that transformation of REF52 cells by ras and SV40 large T antigen requires continuous T antigen expression. Thus, tsA58/T24 H-ras transformants ceased growing when transferred to a restrictive temperature for T antigen expression. Inhibition of cell growth was accompanied by massive accumulations of cholesterol esters, triglycerides and a third lipid species, identified as glycerol ethers on the basis of mobility on TLC. Cholesterol esters were derived from serum lipoproteins, and appeared to accumulate because LDL receptor expression and activity did not decline in growth arrested cells. Triglycerides and glycerol ethers were products of cell metabolism. The process lacked features characteristic of adipocyte differentiation, but may suggest mechanisms important in diseases, such as atherosclerosis, that involve abnormal accumulations of neutral lipids. Accumulating lipid species may also include metabolites induced by ras that accumulate in growth-arrested cells.

Adipose Tissue↗
PubMed1990

Osteosarcoma arising in a benign dermoid cyst of the ovary.

We present a rare case of an osteosarcoma arising in a benign dermoid ovarian cyst. The cyst, removed intact from the right ovary of a 52-year-old Japanese woman, was unilocular, measured 10 x 9 x 8 cm, weighed 176 g, and contained yellow-brownish greasy material. From the inner surface of the cyst there protruded a subsessile solid mass, measuring 3.1 x 2.5 x 2.0 cm, with a variegated cut surface. Histologically, the cyst was an ordinary dermoid cyst, and the solid mass consisted of osteosarcoma with focal chondroblastic differentiation. Postoperative combination chemotherapy was prescribed and the patient remains alive and well 16 months postoperatively. This case is the third documented in the world literature.

Dermoid Cyst↗
PubMed1990

Long-term prognosis of patients with congestive heart failure.

Factors determining prognosis in 100 patients with recent onset of congestive heart failure (CHF) were evaluated. The 1 year, 3 year, 5 year, and 10 year survival rates in the entire CHF group were 78.5%, 59.8%, 50.4% and 14.7%, respectively. No correlations between age, sex, heart rate and cardiothoracic ratio, and the cumulative survival rate were found. The prognosis of patients with CHF due to underlying coronary artery disease or primary cardiomyopathy was poor compared with that of patients with other types of heart disease. Patients whose NYHA classification was class III or VI had a significantly lower survival rate than those in class II. Patients with lower left ventricular stroke work and consecutive ventricular premature depolarization also had a significantly lower survival rate. These results suggest that functional status, underlying heart disease, left ventricular stroke work, and the presence of ventricular tachycardia provide important information regarding the long-term prognosis in patients with congestive heart failure.

Adolescent↗
PubMed1989

Hyperreactio luteinalis in normal singleton pregnancy.

A case of hyperreactio luteinalis in a patient with normal singleton pregnancy is reported. The course of pregnancy had been normal until the 24th week of gestation, when the mother developed lower abdominal pain and signs of virilization. She delivered of a normal female infant at 39 weeks' gestation. The baby did not show any signs of masculinization. Serum testosterone, delta 4-androstene-dione, and 5 alpha-dihydrotestosterone of the mother were markedly elevated. They remained high after the delivery but returned to the normal ranges soon after the partial resection of the enlarged ovaries. Reported causes of hyperreactio luteinalis are reviewed. Their maternal serum androgen levels were compared with cases of luteoma of pregnancy.

Adult↗
PubMed1989

Calcified chronic subdural hematoma with intracerebral rupture forming a subcortical hematoma. A case report.

We report a calcified chronic subdural hematoma which ruptured intracerebrally forming an acute subcortical hematoma in the frontal lobe in a 59-year-old woman with long-standing liver cirrhosis. Both hematoma cavities communicated each other through a small defect within the inner membrane of the subdural hematoma. The content of both hematomas was identical and was of a clay-like clot. The inner membrane around this communication consisted of thick, very vascular granulation tissue with many hemosiderin deposits and was tightly adherent to the cortex. We speculated that a fresh bleeding into the granulation tissue resulted in formation of a subcortical hematoma through a rupture of the inner membrane. Disseminated intravascular coagulation likely played an important role in this unusual condition.

Brain Diseases↗
PubMed1989

Clinicopathologic study of squamous cell carcinoma of the ovary.

Clinicopathologic study was performed on 10 squamous cell carcinomas of the ovary. All four patients with stage II or III lesions had deteriorated within 1 year after the operation, and four of six patients with stage I lesions had survived over 5 years. Clinical findings of the patients with ovarian SCC, including age, chief complaint, clinical stage, and outcome of the patients, were similar to those of common epithelial cancer. The effectiveness of chemotherapy was not shown in this study. Histopathologic study revealed that squamous cell carcinoma may arise not only from epidermis, but also from squamous metaplastic epithelium of respiratory gland.

Adult↗
PubMed1989

Carcinoma of the uterine cervix with variegated histological patterns and calcitonin production.

This is a report of a calcitonin-producing cervical cancer with variegated histological patterns. The levels of calcitonin correlated with the clinical course. Multiple lung metastases were completely controlled by cisplatin/Adriamycin/cyclophasphamide combination chemotherapy, although only for a short period. Microscopically, the tumor showed dominant small cell carcinoma; however, it did show differentiation into large cell nonkeratinizing carcinoma, keratinizing carcinoma, adenocarcinoma, and possibly carcinoid. Ultrastructural study revealed a few dense core secretory granules. Multiple immunohistochemical studies were performed. It is presumed that the tumor originated from the totipotent, immature precursor cells in the cervix and differentiated into endocrine carcinoma, squamous cell cancer, and adenocarcinoma.

Aged↗
PubMed1989

Squamous cell carcinoma arising in mature cystic teratoma of the ovary. Clinicopathologic and topographic analysis.

Clinical and pathologic features of 28 patients with squamous cell carcinoma (SCC) arising in mature cystic teratoma (MCT) of the ovary were analyzed. The overall 5-year survival rate of these patients was 52%. Clinical staging (Stage I versus Stages II or more), histologic differentiation (well versus moderately or poorly differentiated SCC), and the presence of vascular invasion were factors affecting the prognosis of these patients. In 11 tumors, including 2 of the 4 examined in stepwise serial sections, the SCC was considered to have originated from a columnar epithelium (ciliated or nonciliated) or from a metaplastic squamous epithelium. On the other hand, no SCC was a direct transition from the ordinary epidermis of the teratomatous skin tissue. These results strongly support the proposal that SCC arising in MCT derives from the columnar epithelium.

Adult↗
PubMed1989

[Clinical signification of localization of S protein and late components in the skin from lupus patients].

We studied frozen tissue of lesional skin and normal-appearing skin from SLE patients and DLE patients by immunofluorescence. S-protein and late components (C5, C7, C9) were localized at the dermal-epidermal junction of the lesional skin from SLE and DLE patients. All specimens of normal-appearing skin from patients with SLE were free of deposits of S-protein and late components. These results suggest that late components may play a role in the development of skin lesions of SLE and DLE.

Adult↗
PubMed1989

[Aneurysm at the PCA posterior temporal artery junction: a case report].

A case of saccular aneurysm located at the PCA posterior temporal artery junction (E portion of PCA) was reported. A 35-year-old man was referred to us for surgical treatment of intracerebral hematoma in the right temporo-parietal lobes. On admission, the patient was somnolent and there was right oculomotor palsy, left homonymous hemianopsia and left hemiparesis. Left vertebral angiograms revealed a saccular aneurysm at the quadrigeminal segment of the posterior cerebral artery on the right. The hematoma was immediately evacuated by temporal corticotomy, and three weeks later, trapping of the aneurysm was performed through subtemporal approach. Postoperative course was uneventful. However, the left homonymous hemianopsia persisted. This was the only symptom which did persist. The incidence of PCA aneurysm is 1% in all cerebral aneurysms, or 15% in aneurysms of the posterior circulation. The majority of those are located at the junction proximal to the PCA-anterior temporal artery, or proximal to the PCA-posterior lateral choroidal artery junction. In the present case, the aneurysm was located more distally at the PCA-posterior temporal artery junction, and aneurysm at this site has been reported only six times in the literature. In addition to the present case, we reviewed 41 cases (42 aneurysms) in the literature, concerning the operative method and postoperative neurological deficits for the aneurysms of PCA. Neck clipping was performed in 23 cases without any further neurological deficits and trapping or proximal clipping of the aneurysms was performed in 16 cases, in which new neurological deficits developed in 3 cases.

Adult↗
PubMed1988

Rescue of cells from ras oncogene-induced growth arrest by a second, complementing, oncogene.

Established REF52 cells (rat embryo fibroblasts) completely resist stable transformation by ras oncogenes, and simian virus 40 large tumor (T) antigen collaborates with ras to convert REF52 cells to tumorigenic state. A temperature-sensitive simian virus 40 large T antigen (encoded by tsA58) allowed the T24 Ha-ras oncogene to transform REF52 cells in a temperature-dependent manner. Two thirds of the clones transformed with tsA58 and ras became arrested in G2 or late S phase when shifted to a nonpermissive temperature for T antigen stability. Thus, ras induced growth arrest rather than stable transformation in the absence of a functional collaborating oncogene. These results indicate that collaborating oncogenes can regulate cellular responses to ras and have implications regarding therapeutic strategies to control tumor cells expressing activated ras oncogenes.

Animals↗