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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 757 records · Page 42Linked to original sources
PubMed1992

Stimulatory effects of quinpirole hydrochloride, D2-dopamine receptor agonist, at low concentrations on prolactin release in female rats in vitro.

Dopamine (DA) has dual actions (inhibitory and stimulatory) in the regulation of prolactin (PRL) release, depending on its concentration. To investigate the stimulatory effects of DA, perifused rat anterior pituitary cells were exposed to the highly-specific DA D2 receptor agonist, quinpirole hydrochloride (LY). Very low concentrations of LY (10(-12)-10(-10) M) stimulated PRL release and potentiated thyrotropin-releasing hormone (TRH)-induced PRL release. Higher concentrations of LY did not stimulate. Pretreatment with pertussis toxin (30 ng/ml, 24 h) completely abolished these effects of LY. The D2 receptor antagonist, metoclopramide, also blocked the potentiation by LY of TRH-induced PRL release. These data indicate that very low concentrations of dopamine stimulate PRL release via an interaction with a D2 receptor connected to a pertussis toxin-sensitive G protein.

Animals↗
PubMed1992

Long-term clinical observations on feline immunodeficiency virus infected asymptomatic carriers.

Eleven feline immunodeficiency virus (FIV) infected asymptomatic carrier (AC) cats were observed for 2 years for development of acquired immunodeficiency syndrome (AIDS). Four of the 11 (36.4%) showed progression of the clinical stage. Persistent generalized lymphadenopathy was noted in three cats as the first sign of illness after the AC phase, while the other showed lymphadenopathy with signs of AIDS-related complex. In all four cats the AIDS-related complex stage lasted for 10 months or longer, and two showed progression of the disease into AIDS. The two cats showing AIDS illnesses died within approximately 1 year after they had developed persistent generalized lymphadenopathy. Pathology confirmed the diagnosis of AIDS characterized by the presence of depletion lesions in the lymphoid organs, and of severe infections of an opportunistic nature. The overall mortality of FIV infected AC cats during a 2 year period was two out of 11 (18.2%). These cats showed decreased concanavalin A mitogen response of peripheral blood mononuclear cells as the disease progressed.

Animals↗
PubMed1992

Chromosome rearrangements at 12q13 in two cases of chondrosarcomas.

We analyzed the karyotypes of two moderately differentiated (grade 2) chondrosarcomas. Case 1 had a reciprocal translocation between chromosomes 6 and 12, t(6;12)(q25;q13) in most of the cells analyzed, as well as trisomies of chromosomes 7, 8, 11, 17, 19, and 21 and tetrasomy of chromosome 19. A reciprocal translocation involving chromosomes 12 and 19, t(12;19)(q13;q13), was noted as a highly clonal abnormality in the other case. Some cells had t(12;19) as the sole chromosome abnormality. Thus, chromosome rearrangements involving the long arm of chromosome 12 at the same region (q13) were commonly identified in the two tumors. These findings suggest that the rearrangements at 12q13 are nonrandom acquired changes that characterize a subgroup of chondrosarcomas.

Adult↗
PubMed1992

Myasthenia gravis developing after discovery of thymoma.

We report 4 cases of myasthenia gravis in which myasthenic symptoms developed after a thymoma was known to be present. They include 3 invasive thymomas and one thymoma. In 3 of them, myasthenic symptoms developed 2-7 months after removal of the thymoma; in 1 case, myasthenic symptoms developed 11 years after the thymoma was known to be present. We also discuss here the possible pathogenetic mechanism of post-thymomectomic myasthenia gravis, and propose that it is due to the natural course of the disease.

Adult↗
PubMed1992

Tongue cancer treated with irradiation: assessment with MR imaging.

We examined the usefulness of MRI in differentiating post-radiation scar tissue from the residual tumour. Ten consecutive patients who underwent MR imaging before and after radiation therapy were assessed prospectively. T1- and T2-weighted images using a 1.5 unit were obtained in 10 patients (3 T1, 6 T2, 1 T3) at 1 week before irradiation, and 2 weeks, 2 months, 4 months, 6 months and every 6 months thereafter following completion of radiation. Although all T2 and T3 tumours demonstrated high signal intensity compared to muscle on T2-weighted images, the T1 tumour could be demonstrated in only one of three patients. Six patients in whom the primary tumour clinically disappeared demonstrated low signal intensity on T2-weighted images until 4 months after completion of radiation therapy (range 1 week to 4 months). This study suggests that MRI can detect primary tumours larger than T2 (2 cm), and may be useful in assessing the effectiveness of therapy for tongue cancer.

Adult↗
PubMed1992

Malignant fibrous histiocytoma and osteosarcoma in association with fibrous dysplasia of bone. Report of three cases.

Three cases of bone sarcomas arising in fibrous dysplasia (FD) without prior radiation therapy were reported. One of the tumors was a conventional osteoblastic osteosarcoma (OS) and the other two were malignant fibrous histiocytomas (MFH). The lesion of FD was monostotic in two patients and polyostocic (monomelic) in one. Bone sarcomas and FD were detected simultaneously in all cases. One of the MFH cases died 6 months after diagnosis, and the other MFH case and the OS case are alive without disease 3 years and one and a half years after surgery, respectively. Conservative treatment has been selected in most of the patients of FD. We should closely follow up these patients, because bone sarcomas such as OS and MFH could arise at the site of FD. This is the first report of the cases of MFH of bone arising in FD.

Adult↗
PubMed1992

Pulmonary tuberculoma and indications for surgery: radiographic and clinicopathological analysis.

Tuberculomas of the lung are one of the more common lesions presenting a solitary pulmonary nodule, roentgenographically. We treated 36 patients with such nodules and describe here the radiologic-pathologic correlations and surgical treatment. In 21 patients, lung cancer was suspected preoperatively, based on radiographic findings of an ill-defined margin, pleural indentation and spicular radiation. Histologically, the tuberculous granuloma proliferated in the alveolar septa of the surrounding normal lung, often seen as a spicular radiation resembling lung cancer. In eight patients, tuberculoma was suspected because of radiographic findings of calcification and satellite nodules, and anti-tuberculous chemotherapy was prescribed for a few months. As this treatment was ineffective, surgical resection had to be done. Postoperative complications were nil and all of these patients are doing well at the time of preparation of this report. Anti-tuberculous chemotherapy was prescribed for 28 of 36 patients, postoperatively. We believe that surgical intervention is required for selected patients.

Adult↗
PubMed1992

Potent inhibitors of histamine release, two novel triterpenoids from the Okinawan marine sponge Penares incrustans.

Two novel triterpenoids with an unusual 14-carboxyl group, penasterone [1] and acetylpenasterol [2], were isolated from the Okinawan marine sponge Penares incrustans. The structures of 1 and 2 were established mainly on the basis of nmr spectroscopic data. The relative stereochemistry of 1 was confirmed by single-crystal X-ray diffraction analysis. Compounds 1 and 2 potently inhibited histamine release from rat peritoneal mast cells induced by anti-IgE in a dose-dependent manner.

Animals↗
PubMed1992

Chondrosarcoma of the skull base: report of six cases.

Five patients with chondrosarcoma, grade I or II, and one with mesenchymal chondrosarcoma of the skull base were treated at our clinic between 1967 and 1991. The patients were three men and three women who ranged in age from 21 to 39 years. The presenting symptoms were diplopia, decreased visual acuity, or symptoms of involvement of VIIIth and lower cranial nerves. The duration of the symptoms ranged from 18 months to 14 years. A plain skull x-ray and tomography of the skull, computed tomographic (CT) scans, and magnetic resonance images (MRI) revealed a calcified mass. Angiograms showed an occlusion of the arteries or venous sinuses, or both, in four patients, and a distinct tumor stain in one. The tumors were subtotally removed in all six cases. Two patients received postoperative irradiation for the residual tumor. In one patient, extraocular movement was compromised postoperatively, although in the other five patients there was no aggravation of the neurologic signs. Follow-up CT scans and MRI demonstrated no recurrent tumors nor any enlargement of residual tumors. Based on these findings, we advocate aggressive surgical removal of these tumors, which should be augmented by radiation therapy if the postoperative CT scans or MRI reveal residual tumors.

Journal Article↗
PubMed1992

Adenosquamous carcinoma of the lung. Clinicopathologic and immunohistochemical features.

Adenosquamous carcinomas (ASC) of the lung comprise only 1.8% of all pulmonary cancers. Eleven patients with this disease (6 men and 5 women; mean age, 62 years [range, 51 to 78 years]) were treated. On the basis of pathologic and immunohistochemical evidence, the tumors were separated into three groups: five ASCs of predominantly glandular type, which may originate from squamous metaplasia in a preexisting adenocarcinoma; three mixed type ASCs, possibly derived from the transition of undifferentiated carcinoma to two different elements; and three predominantly squamous type ASCs resembling high-grade muco-epidermoid carcinoma. The 5-year survival rate of 35% for patients with ASCs was the same as that for patients with other nonsmall cell carcinomas. For two patients with ASCs of the predominantly glandular type and for one with the mixed type, resection was incomplete because of extensive local disease. All tumors of the predominantly squamous type could be excised completely. However, differences in the malignant potential of these three types of ASCs are still controversial.

Adenocarcinoma↗
PubMed1992

In vitro formation of estrogen receptor-heat shock protein 90 complexes.

We previously showed that the 9 S estrogen receptor can be reconstituted from purified vero ER (estradiol binding subunit) and purified hsp 90 (heat shock protein 90) in vitro [Inano, K. et al. (1990) FEBS Lett. 267, 157-159]. In this study, we further characterized our reconstitution system to investigate the mechanism underlying the formation of 9 S ER. When a vero ER preparation stored at 4 degrees C for more than 20 h after affinity chromatography was used for the reconstitution of 9 S ER, 0.5 M NaSCN was essential, but not Na2MoO4 or other reagents. When, however, vero ER was used within 3 h after dissociation from an affinity resin, 9 S ER could be reconstituted in a relatively high yield without NaSCN. Moreover, if such a fresh vero ER preparation was used, 9 S ER could be reconstituted in the absence of NaSCN from not only unoccupied vero ER but also the occupied form. From these results it was suggested that the conformation of purified vero ER tends to change quickly in a time dependent manner, and so a chemical perturbant, NaSCN, is generally necessary for the reconstitution of 9 S ER from purified vero ER and purified hsp 90. The concentration of hsp 90 required for the reconstitution was only about 1.0 microM, which was lower than its physiological concentration. Based on these results, the mechanism underlying the formation of 9 S ER was discussed.

Animals↗
PubMed1992

The effect of breast self-examination on early detection and survival.

To investigate the effect of breast self-examination (BSE), we compared the stages, survival, and the risk of death for 355 patients with breast cancer detected by BSE with those for 1,327 patients with breast cancer detected by chance. The early stages of the disease were found to be more common among the symptomatic breast cancer patients detected by BSE than those by chance. The 5-year overall survival rate was 94.4% for the symptomatic patients detected by BSE, and was significantly higher by 8.7% than that (85.7%) for patients detected by chance (P less than 0.001). The 10-year survival rate was 81.6% for patients detected by BSE, and 76.6% for cases detected by chance (the difference was not significant). The overall difference between the two survival curves was statistically significant by the logrank test (P less than 0.01). A multivariate analysis using the Cox proportional hazards model showed that the risk of death for patients detected by BSE was smaller by 0.570 times than that for patients detected by chance, which was statistically significant (P less than 0.05). The effect of biases inherent to BSE in the survival analysis cannot be controlled completely even after conducting multivariate analysis. These results suggest that BSE may contribute to the reduction of the risk of death through early detection of breast cancer. However, further examination should be conducted by other methods to obtain conclusive evidence.

Breast Neoplasms↗
PubMed1992

Clinicopathologic characteristics and prognosis of breast cancer patients associated with pregnancy and lactation: analysis of case-control study in Japan.

Clinicopathologic characteristics and prognosis of breast cancer patients associated with pregnancy and lactation were clarified by means of a case-control study of matched non-pregnant and non-lactating patients with breast cancer. From 18 institutions in Japan, a total of 192 subjects with breast cancer diagnosed during pregnancy (72 cases) and lactation (120 cases) were collected between 1970 and 1988, accounting for 0.76% of all breast cancer patients. The duration of symptoms was longer and tumor size was larger in the study subjects. Although the disease-free interval was longer than that in the control patients, the survival time was shorter. There was no characteristic difference in histologic type. Vascular invasion and lymph node metastasis were found more frequently in the subjects. The positive rates of estrogen receptor and progesterone receptor were lower in the subjects. The 5- and 10-year survival rates of the study patients were 65% and 55%, respectively, and these survivals were significantly lower than those of the control (P < 0.001). The survival rates were poorer in the subjects, in accordance with stage and lymph node metastasis. The results suggest that most of the patients with breast cancer diagnosed during pregnancy and lactation are in a more advanced stage because of a delay in detection and diagnosis, and hence have unfavorable prognosis. Therefore, it is important to diagnose and treat early for improvement of prognosis in patients with breast cancer during pregnancy and lactation.

Adult↗
PubMed1992

Crystal structure and molecular conformation of achatin-I (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide containing a D-amino acid residue.

In order to investigate the active conformation of achatin-I (H-Gly-D-Phe-Ala-Asp-OH), an endogenous neuropeptide from the Achatina fulica ganglia, its crystal structure and molecular conformation were analysed by the X-ray diffraction method. Crystals from methanol/dioxane are monoclinic, space group P2(1) with a = 5.083(1), b = 9.125(1), c = 20.939(3) A, beta = 94.73(1) degrees. The structure was solved by direct methods and refined to R = 0.051 for 1714 independent reflections with /Fo/ greater than sigma (Fo). The molecule exists as a zwitterion with the Gly N-terminal end protonated and Asp beta-carboxyl deprotonated; the C-terminal of Asp is in a neutral state. The molecule takes a kind of beta turn structure with the D-Phe-Ala residues at the corner of the bend. This turn conformation is primarily formed by the strong intramolecular hydrogen bonds of NH(Gly)...O delta 1 (Asp) and NH(Asp)...O delta 1 (Asp) pairs, thus forming a 15-membered ring structure. Judging from the published data concerning the structure-activity relationship, this turn conformation may reflect an important feature related to the neuroexcitatory activity of achatin-I.

Amino Acid Sequence↗
PubMed1992

Identification of inositol 1,4,5-trisphosphate binding in human pheochromocytoma.

An attempt was made to identify a specific binding of inositol 1,4,5-trisphosphate (IP3) to human chromaffin cell tumors. Crude microsomal fractions of pheochromocytomas possessed significant binding sites for [3H]IP3 with high- and low-affinity constants (Kd = 5.46 and 538 nM, respectively). The binding to these sites was rapid, saturable (reached equilibrium by 1 min at 0 degrees C) and reversible. Competition studies with other inositol phosphate analogs indicated the stereotypic specific binding for IP3. Although no significant difference was observed in the binding densities of IP3 between pheochromocytomas and adrenal nonfunctioning adenomas, the values of high-affinity constants were significantly lower in the former than the latter group (5.77 +/- 1.07, n = 5 vs. 11.30 +/- 1.98 nM, n = 4, p less than 0.05). The present data indicate that characteristics of IP3 binding sites are congruous with their receptor functions and that changes in its binding sites may contribute to the biochemical dissimilitudes in pheochromocytomas.

Adenoma↗