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Biomedical subjects

T Nemoto

Publications and source records attributed to T Nemoto.

At least 145 records · Page 8Linked to original sources
PubMed1994

Human arylhydrocarbon receptor: functional expression and chromosomal assignment to 7p21.

We isolated the human arylhydrocarbon receptor (AhR) cDNA from a human lung cDNA library, by using mouse AhR cDNA as a labeled probe. The nucleotide sequence of cloned human AhR cDNA is identical to the previously reported human AhR sequence [Dolwick et al. (1993), Mol. Pharmacol. 44, 911-917] from cell line HepG2. The overall amino acid identity with mouse AhR from cell line Hepa-1 is 72.5%. The human AhR expressed either in COS-7 cells or in a reticulocyte lysate in vitro translation system showed specific dioxin-binding activity and Arnt-dependent DNA-binding activity. Chromosomal localization of the AhR gene was determined to be chromosome 7p21 by fluorescent in situ hybridization and DNA blot hybridization using 23 human x mouse or Chinese hamster hybrid cell DNAs.

Amino Acid Sequence↗
PubMed1994

Exposure to breastmilk in infancy and the risk of breast cancer.

Early childhood nutrition may affect the subsequent risk of breast cancer in adulthood. We examined the association of having been breastfed with risk of breast cancer in a case-control study of women age 40-85 years in western New York. Cases (N = 528) had newly diagnosed primary, pathologically confirmed breast cancer; controls (N = 602) were randomly selected from the same community and were frequency matched on age. Having been breastfed was associated with decreased risk. The multivariate adjusted odds ratio was 0.74, and the 95% confidence interval was 0.56-0.99. We found little difference in the association for pre- and postmenopausal women despite a much higher frequency of breastfeeding among the older women. These findings indicate that early nutriture in general and bottle feeding in particular may relate to breast cancer development in adulthood.

Adult↗
PubMed1994

Myxoid leiomyoma of the vulva mimicking aggressive angiomyxoma.

A case of vulvar leiomyoma with extensive myxoid change in a 40 year old female is described. The tumor had a unique connection with a non-degenerative leiomyoma that compressed the rectum and the bladder. Scattered smooth muscle cells in a loose myxoid stroma were immunoreactive for desmin. Fibroblast-like spindle cells were immunoreactive for vimentin but not for desmin. The initial, although incorrect, pathological diagnosis of the tumor was aggressive angiomyxoma based on the similarity in both clinical and pathological aspects with this more invasive tumor. Myxoid vulvar leiomyoma should also be differentiated from angiomyofibroblastoma. The key to the differential diagnosis is the presence of interlacing smooth muscle cells and an awareness of tendency toward myxoid change in vulvar leiomyomas.

Adult↗
PubMed1994

Biophysical properties of protein-free, totally synthetic pulmonary surfactants, ALEC and Exosurf, in comparison with surfactant TA.

An artificial pulmonary surfactant prepared from chloroform-methanol extract of bovine pulmonary surfactant (surfactant TA) has been shown to be effective in both the prevention and the treatment of respiratory distress syndrome in premature babies. Recently, two types of protein-free totally synthetic surfactants, artificial lung expanding compound (ALEC) and Exosurf, have been evaluated in clinical trials of surfactant therapy. Artificial lung expanding compound was used initially as a dry powder, but is now prepared as a crystalline suspension in saline at 4 degrees C. In this study we compared the biophysical properties of three different forms of ALEC (dry powder, crystalline suspension at 4 degrees C and 37 degrees C), Exosurf and surfactant TA (Surfacten) using a modified Wilhelmy surface balance and a pulsating bubble surfactometer. Surface activity of a crystalline suspension of ALEC in cold saline was no better than the dry powder of ALEC. Surfactant activity of ALEC was improved by addition of hydrophobic surfactant protein B and C (SP-B, SP-C) which are important constituents of surfactant TA. Surface properties of ALEC in any form and Exosurf were not superior to those of surfactant TA. These results suggest that a surfactant which contains SP-B and SP-C does not necessarily have to be dry or crystalline for an effective exogenous surfactant.

Adsorption↗
PubMed1994

Cysteine protease activity of streptococcal pyrogenic exotoxin B.

Streptococcal pyrogenic exotoxin B (SPE B) was purified and its protease and mitogenic activities were investigated. The apparent molecular mass of SPE B purified in the presence of iodoacetic acid was 42 kDa, whereas 29-kDa SPE B was predominant without the reagent. A polyclonal antibody raised against the 29-kDa species reacted with both species, indicating that the 42-kDa species was a precursor of the 29-kDa entity. Both the 42- and 29-kDa species enhanced [3H]thymidine incorporation into human peripheral blood mononuclear cells, whereas neither had any effect on T cell depleted mononuclear cells. The 29-kDa SPE B possessed caseinolytic activity, with an optimal pH of 8, and the activity was specifically suppressed by the antibody. A group of cysteine protease inhibitors, but no serine-, metallo-, or acidic-protease inhibitors, limited the protease activity, whereas dithiothreitol increased the activity. The DNA sequence around a putative active cysteine residue was identical among the speB genes from Streptococcus pyogenes R70, NY-5, and T19. Taken together, these results indicate that SPE B is identical to a cysteine protease, streptopain (EC 3.4.22.10).

Amino Acid Sequence↗
PubMed1994

Superior vena cava syndrome caused by a right apical tense bulla.

Superior vena cava (SVC) syndrome is caused by several diseases, although to our knowledge, a bullous lesion has not been reported previously. In the present case, severe pleural adhesion prevented the expanding bulla from stretching the visceral pleura and from compressing the residual lung, subsequently causing compression of the SVC and thus SVC syndrome.

Female↗
PubMed1994

Specific expression of the neurofibromatosis type 1 gene (NF1) in the hamster Schwann cell.

The gene responsible for neurofibromatosis type 1 (NF1) has sequence homology to the GTPase-activating protein (GAP) and demonstrates GAP activity against ras p21. To study tissue-specific and/or tumor-specific expression of the NF1 gene product, now called neurofibromin, immunostaining and immunoblotting were applied to the N-nitroso-N-ethylurea (ENU)-induced Syrian hamster neurofibromatosis model using polyclonal antibodies against the NF1 fusion protein and a synthetic peptide. Strong expression was observed specific to the Schwann cells of the normal peripheral nerves by immunostaining. Neoplastic Schwann cells showed specific binding of anti-NF1; however, the frequency of positive cells was diminished. Immunoblotting also revealed positive expression of the 250-kd NF1 gene product in the brain, the normal peripheral nerves, and 7 of 14 ENU-induced neurofibromas. Although ENU-induced melanoma and Wilms' tumor were negative for neurofibromin, foci of Schwannian differentiation in both primary and transplanted melanomas were positive. These results suggest that neurofibromin plays some role in differentiation and growth regulation of the Schwann cell.

Animals↗
PubMed1993

Results of salvage mastectomy for local recurrence after breast-conserving surgery without radiation therapy.

BACKGROUND: Between 1975 and 1987, 128 patients with infiltrating breast cancer, categorized as clinical Stage I and II disease, were treated by breast conservation surgery without radiation therapy. MATERIALS: After a median disease-free interval of 20 months (range, 8-64 months), 25 of 128 patients had local recurrence, for which salvage mastectomy was performed. The results of modified radial mastectomy as a salvage procedure were analyzed in these 25 patients. RESULTS: After a median disease-free interval of 52 months (range, 8-75 years) after the salvage procedure, 12 patients had chest wall and distant recurrences, whereas 13 patients remained free of disease. The 5-year actuarial disease-free and overall survival rates after the salvage mastectomy were 51% and 65%, respectively. CONCLUSIONS: Univariate analyses of factors affecting disease-free survival and overall survival showed that the size of the local recurrence (< or = 2 cm) (P = 0.009) and the number of pathologically positive axillary nodes at the time of the salvage procedure (fewer than four nodes) (P = 0.002) were associated with a better prognosis.

Adult↗
PubMed1993

In vivo antimelanoma effects of 4-S-cysteaminylphenol, a newly synthesized therapeutic agent specific to melanoma.

Antimelanoma effects of 4-S-cysteaminylphenol (4-S-CAP), which is a newly synthesized melanin precursor, as a chemotherapeutic agent specific to malignant melanoma were determined in an in vivo system using mouse B16 melanoma. The intraperitoneal injection of 4-S-CAP induced a slight delay in the growth period of subcutaneous melanoma of C57BL/6 mice. Survival times of mice after treatment with 4-S-CAP were a little longer than those of control mice (P < 0.05), although all mice died from the local growth of tumours. The viable cell ratio of in vivo subcutaneous tumour cells reduced to 52.8% within 24 h after treatment with 4-S-CAP, but the ratio had recovered to the control level 72 h after treatment (> 90%). Similarly, the proliferating-cell-nuclear-antigen-positive cell ratio of melanotic melanoma had reduced 24 h after treatment and recovered within 72 h after treatment, while 4-S-CAP had no effect on amelanotic tumours. The formation of lung colonies by intravenous inoculation of malignant melanoma cells was compared between mice with intraperitoneal injection of 4-S-CAP and phosphate-buffered saline only. The 4-S-CAP-treated mice had significantly fewer lung colonies compared with the control mice (P < 0.01). The results indicate that the agent, 4-S-CAP, would have a therapeutic effect on malignant melanoma for a short time in vivo and therefore the agent can be effective against a small number of tumour cells, such as lung colonies, although it had little effect on the local tumours.

Animals↗
PubMed1993

Closed continuous irrigation as a treatment for infection in the hand.

A method of closed irrigation has been devised to treat infections in the hand. After adequate débridement, two tubes are placed in the infected area, an inlet tube and an outlet tube. For a small infection, one tube serves both purposes. The wound is closed completely. Irrigation with saline and antibiotic solution is continued for 1 week, extended up to 3 weeks in cases of severe infection. This method has been applied in 31 cases including pyogenic tenosynovitis, tuberculous tenosynovitis, pyogenic arthritis, osteomyelitis, bite injury, crush injury and amputation stump infection. Infection healed primarily in 29 cases. Further surgery was needed in two cases which healed finally.

Adolescent↗
PubMed1993

N-nitroso-N-ethylurea-induced hamster melanoma: a new method for efficient induction and schwannian differentiation of melanoma.

Melanocytic tumors as well as multiple neurofibromas were induced in 35 of 88 Syrian golden hamsters by a single s.c. administration of 100 mg/kg of N-nitroso-N-ethylurea applied 48 h after birth. The lesions were all observed proliferating in the dermis and demonstrated melanosomes and premelanosomes. High cellularity, nuclear atypia and transplantability of the tumors in outbred hamsters suggested a malignant nature. Some of the melanomas were morphologically heterogenous and contained Schwann-like cells as minor components. In addition, transplantation of the melanomas resulted in increased schwannian differentiation even for primary tumors which did not contain any Schwann-like cell foci. One of the transplanted melanomas mimicked malignant peripheral nervous tumor. Schwannian differentiation was also proved by the fact that glial fibrillary acidic protein was positive in 22.2% of the cases. The present results suggest that the induced hamster melanomas originate from neural crest-derived cells which are able to differentiate into both melanocytes and Schwann cells.

Animals↗
PubMed1993

Pure progressive autonomic failure: a clinicopathological study.

Two cases of pure progressive autonomic failure (PAF) are presented. A postmortem study of one case (case 2) showed a pathology resembling that of Parkinson's disease. Marked cell loss was noted in the substantia nigra, nucleus ceruleus, and intermediolateral column of the spinal cord, while cell loss in the sympathetic ganglion was not remarkable. This case may be an exceptionally rare case of late-onset PAF in which autonomic failure was mainly ascribed to preganglionic (and central) pathology, although autonomic function tests suggested postganglionic sympathetic disorder in both cases.

Aged↗
PubMed1993

Dual roles of 90-kDa heat shock protein in the function of the mineralocorticoid receptor.

Association of the 90-kDa heat shock protein (HSP90) is required for the high-affinity ligand-binding of the glucocorticoid receptor (GR), but not for that of the androgen receptor [Ohara-Nemoto, Y., Nemoto, T., & Ota, M. (1991) J. Biochem. 109, 113-119]. In the present study, we investigated the ligand- and HSP90-binding characteristics of the mineralocorticoid receptor (MR), which shares to some degree the ligand-binding specificity of the GR. A truncated human MR (designated MR351) starting from Gly-351 was translated in vitro with rabbit reticulocyte lysate. Scatchard analysis revealed the presence of a single class of high-affinity binding sites for [3H]aldosterone (Kd = 0.35 +/- 0.2 nM), comparable to those of the native receptor in target tissues. Glycerol gradient centrifugation and immunoadsorption analyses showed that MR351 associated with rabbit HSP90. Exposure to 0.4 M NaCl induced the dissociation of HSP90 from MR351 and simultaneously enhanced binding of MR351 to DNA-cellulose. Moreover, when measured at 10 nM, HSP90-free MR351 showed only 9% of the [3H]aldosterone-binding found in the presence of HSP90. On the other hand, when MR351 was expressed in Escherichia coli as a protein tagged with a histidine hexamer at the N-terminus (designated H6MR351), specific binding of [3H]aldosterone was detected. The binding affinity (Kd = 338 +/- 45 nM) was, however, 1,000-fold lower than that of MR351 translated in vitro.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Coronary artery lesions in Takayasu arteritis: pathological considerations.

This communication reviews the clinical and pathological features of coronary artery lesions in Takayasu arteritis. The incidence of coronary artery involvement has been reported to be 9% to 10%, and is observed mainly in autopsy cases because coronary artery disease is usually not evident until the occurrence of angina pectoris or myocardial infarction, or after the onset of congestive heart failure. On the basis of pathological features, the following three types of coronary artery lesions can be distinguished: type 1, stenosis or occlusion of the coronary ostia and the proximal segments of the coronary arteries; type 2, diffuse or focal coronary arteritis, which may extend diffusely to all epicardial branches or may involve focal segments, so-called skip lesions; and type 3, coronary aneurysm. Most of the coronary artery lesions in Takayasu arteritis are of type 1. Narrowing of the coronary arteries is mainly due to the extension of the inflammatory processes of proliferation of the intima and contraction of the fibrotic media and adventitia from the ascending aorta. In some cases, coronary stenosis may be caused by coronary arteritis as skip lesions in Takayasu arteritis, but even in these cases the lesions have been reported to affect mainly the proximal segments of the coronary arteries. Diffuse lesions of the coronary artery and coronary artery aneurysm seem to be very rare in Takayasu arteritis. Other causes of coronary ostial stenosis, coronary arteritis and coronary artery aneurysm are also discussed.

Adult↗
PubMed1992

Association of the 90-kDa heat shock protein does not affect the ligand-binding ability of androgen receptor.

An N-terminal truncated androgen receptor with putative DNA- and ligand-binding domains (AR438) and that with a ligand-binding domain (AR612) were expressed under control of the T7 promoter in E. coli or translated in vitro with rabbit reticulocyte lysate, and their ligand-binding properties and the interaction with HSP90 were investigated. Bacterially expressed AR438 and AR612 bound a synthetic androgen, [3H]R1881, with apparent dissociation constants of 2.6 +/- 0.2 and 3.1 +/- 0.7 nM, respectively, values which are comparable to those of androgen receptor in target tissues. The recombinant androgen receptors sedimented at the 4-5 S region irrespective of the presence of 10 mM tungstate, indicating that the receptor exists free from HtpG, which is the bacterial homolog of eukaryotic HSP90. The apparent dissociation constant of truncated androgen receptors translated in vitro was 0.1 nM for AR438 and 0.2 nM for AR612. Sedimentation coefficients of in vitro translated molecules were converted from 7-8 S in the presence of tungstate to 3 S in the absence of tungstate. Both AR438 and AR612 translated in vitro were retained by anti-rat HSP90 antibody-protein A Sepharose. Exposure to 0.3 M NaCl in the presence of ligand caused dissociation of AR438 and AR612 from HSP90, and concomitantly, the DNA-cellulose binding ability of AR438 was enhanced. Thus, we conclude that the androgen receptor associates with HSP90 through the ligand-binding domain and that this association prevents the interaction of the androgen receptor with DNA. However, HSP90 seems to have little effect on the ligand-binding characteristics of the androgen receptor.

Animals↗