Biomedical subjects

T Sakurai

Publications and source records attributed to T Sakurai.

At least 973 records · Page 54Linked to original sources

PubMedDate not supplied

Origin attribution of polychlorinated dibenzo-p-dioxins and dibenzofurans in sediment and soil from a Japanese freshwater lake area through congener-specific data analysis.

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDDs/PCDFs) in sediment and soil from a freshwater lake area were congener-specifically determined. The obtained data were examined to estimate the major origins of these compounds, with the aid of principal component analysis (PCA). Four major principal components (PCs) were obtained, and three of them were attributed to PCDDs/PCDFs in the atmosphere, in a diphenyl ether herbicide and in pentachlorophenol, based on congener-specific comparisons with references. One PC remained unattributed. These four were interpreted as the major origins of PCDDs/PCDFs in the area. The relative influence of the origins was also investigated.

Agriculture↗

PubMedDate not supplied

Model simulation of environmental profile transformation and fate of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by the multimedia environmental fate model.

Environmental profile transformation and fate of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were studied using the fugacity-based multimedia environmental fate model. Mass fluxes between compartments were estimated by the steady-state modeling. From the model estimates, major mass fluxes coming from emission source were shown to go to the soil and water through wet/dry deposition, then go to degradation mainly in the soil and sediment. Simulation of homologue profile transformation was also performed and some controlling parameters were pointed out. Part of profile transformation phenomenon was simulated well at least qualitatively, which was the result of the difference in the physical/chemical properties of homologues. Long-term environmental fate of PCDD/PCDF was also studied using the non steady-state multimedia fate model.

Air Pollution↗

PubMedDate not supplied

Simulation of long-term environmental dynamics of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans using the dynamic multimedia environmental fate model and its implication to the time trend analysis of dioxins.

Long term environmental fate of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) were studied using the fugacity-based dynamic multimedia environmental fate model. New formulation about soil wind erosion into air was included into the model. Effect of process assumption, sensitivity analysis for parameters, and tentative validation against the measured sediment core analysis was performed. Mass fluxes between compartments were estimated by the dynamic modeling. From the model estimates, major mass fluxes coming from emission source were shown to go to the soil and water through wet/dry deposition, then go to degradation mainly in the soil and sediment. Major mass fluxes of TCDD and OCDD come from the impurities in CNP (Chlornitrofen) and PCP (Pentachlorophenol) directly into the soil. Consideration about multimedia environmental dynamics using the modeled mass fluxes was shown in the discussion.

Benzofurans↗

PubMedDate not supplied

Cloning of a cDNA encoding a non-isopeptide-selective subtype of the endothelin receptor.

Endothelin-1 was initially identified as a 21-residue potent vasoconstrictor peptide produced by vascular endothelial cells, but was subsequently found to have many effects on both vascular and non-vascular tissues. The discovery of three isopeptides of the endothelin family, ET-1, ET-2 and ET-3, each possessing a diverse set of pharmacological activities of different potency, suggested the existence of several different endothelin receptor subtypes. Endothelins may elicit biological responses by various signal-transduction mechanisms, including the G protein-coupled activation of phospholipase C and the activation of voltage-dependent Ca2+ channels. Thus, different subtypes of the endothelin receptor may use different signal-transduction mechanisms. Here we report the cloning of a complementary DNA encoding one subtype belonging to the superfamily of G protein-coupled receptors. COS-7 cells transfected with the cDNA express specific and high-affinity binding sites for endothelins, responding to binding by the production of inositol phosphates and a transient increase in the concentration of intracellular free Ca2+. The three endothelin isopeptides are roughly equipotent in displacing 125I-labelled ET-1 binding and causing Ca2+ mobilization. A messenger RNA corresponding to the cDNA is detected in many rat tissues including the brain, kidney and lung but not in vascular smooth muscle cells. These results indicate that this cDNA encodes a 'nonselective' subtype of the receptor which is different from the vascular smooth muscle receptor.

Amino Acid Sequence↗

PubMedDate not supplied

Evaluations of the prescription order entry system for outpatient clinics by physicians in the 80 university hospitals in Japan.

We investigated the evaluations of the prescription order entry system by the physicians who are the direct users of this system. Questionnaires were sent to 400 staff physicians of 80 medical school affiliated hospitals, out of which 76% responded. Among the respondents, 48 per cent are making use of the computerized outpatient prescription order entry system, and 52 per cent are not. The result shows 78% of the physicians are in favor of the prescription order entry system; the most dissatisfied opinion of the physicians toward the system was that the input took too much time thus reduced the communication with the patient. Physicians who are using the system seemed to favor the system more than the physicians who are not using it.

Attitude to Computers↗

PubMedDate not supplied

Cytologic grading of invasive breast carcinoma. Correlation with clinicopathologic variables and predictive value of nodal metastasis.

OBJECTIVE: To estimate cytologic grade and correlate it with the other known prognostic factors, such as tumor differentiation, growth fraction, estrogen receptor status and nodal status. STUDY DESIGN: Fine needle aspirates from 104 invasive ductal carcinomas were stained by the Papanicolaou method and examined for necrosis, cellular size, nuclear/cytoplasmic ratio, nuclear pleomorphism, nucleoli, chromatin granularity and density of chromatin. We established a semiquantitative scoring system based on the above features and correlated cytologic findings with clinicopathologic variables. RESULTS: Histologic grade correlated positively with cytologic grade and negatively with estrogen receptor positivity. Moreover, high cytologic grade was associated with nodal metastasis and proliferative index labeling by MIB-1. CONCLUSION: This study showed that our grading system for breast cancer on fine needle aspiration cytology is feasible on a routine diagnostic basis. Cytologic grading can provide more information than usual on tumor biologic behavior.

Antigens, Nuclear↗

PubMedDate not supplied

Cytology of pigmented renal cell carcinoma. A case report.

BACKGROUND: Pigmented renal cell carcinoma is very rare, and there have been no reports on its cytologic findings. CASE: A 40-year-old female with pigmented renal cell carcinoma had cytologic findings similar to those of clear cell carcinoma except for the presence of melaninlike brown pigment. CONCLUSION: It is important to recognize that renal cell carcinoma may contain melaninlike brown pigment seen on cytologic examination of renal aspirates.

Adult↗

PubMedDate not supplied

Deafness in cryoglobulinemia.

We present a histopathological study of 44-year-old female with essential cryoglobulinemia. She had suffered from purpura and ulcer in winter, bilateral tinnitus and progressive hearing loss. An audiogram taken a week before her death showed bilateral total deafness. In the cochlea of the left temporal bone, the organ of Corti was either missing or present as a mound. The stria vascularis was atrophic throughout the cochlea. The tectorial membrane showed drooping and encapsulation. Reissner membrane was in the normal position. Eosinophilic precipitate was noted in the scala media at the site where Reissner membrane bulged. The spiral ganglion cells were well preserved. In the lower basal turn, there was fibrosis and ossification intermingled in the scala tympani. Ossification was most marked near the basal end. The semicircular canals and vestibule were almost totally ossified and fused with surrounding bone. There was a small, cyst-like structure in the vestibule containing eosinophilic fluid. Our findings indicate that the deafness was the result of circulatory disturbance due to cryoglobulinemia. To our knowledge, this is the first cryoglobulinemia case in which temporal bone findings are reported.

Adult↗

PubMedDate not supplied

Disappearance curves for tumor markers after resection of intrathoracic malignancies.

Determination of the standard elimination kinetics of tumor markers will be helpful in the diagnosis of malignancies. We analyzed the disappearance curves for serum tumor marker levels after resection of intrathoracic malignancies. Serum levels of CEA, SLX, AFP, CA 19-9, SCC, TPA and CYFRA were measured several times after surgery in a total of 40 patients. To obtain precise biological half-lives, we applied non-linear least square analysis, taking into consideration the possibility of residual tumor cells. Disappearance curves were monophasic for CEA, SCC, TPA, CYFRA and SLX and biphasic for CA 19-9 and AFP. Temporary elevation of serum levels after surgery was observed for SCC, TPA and CYFRA. The average half-lives of CEA, SLX, SCC, TPA and CYFRA were 1.5 days, 2.7 days, 2.2 hours, 2.5 hours and 1.5 hours, respectively. The average half-life of CA 19-9 was 0.5 days in the first compartment and 4.3 days in the second compartment, while that of AFP was 1.0 days and 6.3 days, respectively. These values will be helpful in the interpretation of serum tumor marker levels after surgery.

Adult↗

PubMedDate not supplied

Autoimmune hemolytic anemia and myasthenia gravis.

A case of autoimmune hemolytic anemia associated with myasthenia gravis in a 33-year-old female is presented. The association of autoimmune hemolytic anemia and myasthenia gravis is a very rare event, with only eight cases reported. The known association of these two diseases is reviewed. To our knowledge, this is the first reported case in which autoimmune hemolytic anemia preceded systemic myasthenia gravis.

Adult↗

PubMedDate not supplied

Development and trial operation of a World Wide Web-based data entry system for the collection of statistical data on the management of the national university hospitals in Japan.

A WWW-based, on-line, data-entry system for the collection of statistical data on the management of Japanese national university hospitals has been developed. Trial operation of the system showed that it can reduce the labour and budgetary costs of data collection and also demonstrated that an on-line, data-entry system is feasible in Japan. In April 1997, we began production use of the system, and we are to develop another WWW-based data-entry system that can deal with all other statistics on hospital management.

Computer Communication Networks↗

PubMedDate not supplied

Thymidine phosphorylase expression in invasive carcinoma: correlations with clinicopathologic variables and in vitro chemosensitivity to 5-fluorouracil.

BACKGROUND: Thymidine phosphorylase (TP) is critical for angiogenic activity, but little information is available on the relationship between TP expression and other Clinicopathologic variables. Furthermore, the relationship between TP and chemosensitivity is still debated. MATERIALS AND METHODS: The expression of TP was examined in 116 primary breast carcinomas and in vitro chemosensitivity was assessed in 67 of them by histoculture drug response assay (HDRA) using 5-fluorouracil (5-FU). RESULTS: Tumor cell TP expression was significantly inversely correlated with histological grade and positively correlated with Bcl-2 expression, but no association with other tumor variables was found. Unexpectedly, TP immunoreactivity was not related to 5-FU chemosensitivity. CONCLUSION: The present results suggest that TP is important for remodeling the existing vasculature early in tumor development and intraductal extension, expressions of TP and Bcl-2 are tightly linked and TP status can not generally predict chemotherapeutic sensitivity for 5-FU as a single molecular marker.

Antimetabolites, Antineoplastic↗

PubMedDate not supplied

Stent-graft placement for pseudoaneurysm of the aorta.

PURPOSE: To evaluate the use of endovascular stent-graft placement to repair pseudoaneurysm of the aorta. METHODS: Six patients were treated with stent-grafts for pseudoaneurysms located in the thoracic aorta (n=2), thoracoabdominal aorta (n=3), and abdominal aorta (n=1). Etiologies of the pseudoaneurysms included leakage from surgical graft, penetrating atherosclerotic ulcer, pneumonia, perforated esophageal ulcer, and mycotic aneurysm. All patients were clinically considered to be at high surgical risk. RESULTS: Stent-grafts were successfully placed in all patients. There was one death in the perioperative period due to massive hemoptysis before stent-grafting. Two patients died of persistent infection. One patient with persistent perigraft leak died of rupture. Two other patients needed no further therapy for pseudoaneurysm. CONCLUSION: Stent-graft placement for pseudoaneurysm of the aorta can play the role of a temporizing method prior to surgical repair in high-risk cases and be a therapeutic alternative in cases without infection or perigraft leakage.

Aneurysm, False↗

PubMedDate not supplied

Overexpression of p27 protein in human breast cancer correlates with in vitro resistance to doxorubicin and mitomycin C.

BACKGROUND: The cycle regulatory protein p27, an inhibitor of cyclin-dependent kinase (CDK), has been attributed a role in resistance to cancer chemotherapy. However, the predictive value of p27 for chemosensitivity of breast cancer is still unclear. We therefore analyzed the in vitro chemosensitivity to a series of anticancer agents in fresh breast cancer specimens and correlated it with the respective expression levels of p27. MATERIALS AND METHODS: The expression of p27 protein was examined immunohistochemically in 119 patients with primary breast cancer. The in vitro chemosensitivity was assessed by the histoculture drug response assay (HDRA) using mitomycin C (MMC), 5-fluorouracil (5-Fu), Doxorubicin (DXR), cisplatin (CDDP) and cyclophosphamide (CPA). RESULTS: Fifty-six (47%) of the 119 patients demonstrated p27 overexpression. The susceptibility of DXR and MMC in tumors with high p27 expression was significantly higher than that in tumors with low p27 expression. CONCLUSION: Immunohistochemical results regarding p27 might be therapeutically useful as an indicator of response to DXR and/or MMC based adjuvant chemotherapy for breast cancer.

Antineoplastic Agents↗

PubMedDate not supplied

Novel polymorphisms in prostate specific antigen gene and its association with prostate cancer.

Prostate-specific antigen (PSA) is now used widely for the diagnosis and monitoring of patients with prostate cancer. The PSA gene is a target of the androgen receptor (AR) which interacts with androgen response elements (AREs) in the PSA gene promoter. Recently, we identified two novel polymorphisms in the PSA promoter ARE2 region in breast cancer. We hypothesized that some genetic variations might also exist in the AREs of prostate cancer, and that feature might correlate with cancer development and/or progression. To test this hypothesis, three AREs of the PSA gene promoter were characterized for 47 prostate cancer cases and 105 controls from the Japanese population. We demonstrated the presence of two polymorphisms at positions -252 (G or A) and -205 (A or AA), which were the same as those we have found in breast cancer. Interestingly, the -252 A was linked with the presence of -205 AA, and the -252 G was always linked with the presence of -205 A. Therefore, only A-AA and G-A (-252--205) alleles were present in the Japanese population. The proportion of patients who were either heterozygotes or homozygotes for the A-AA allele was not significantly different from that observed among 105 individuals without cancer (p = 0.726). However, comparing with G-A allele homozygotes, prostate cancer patients carrying at least 1 A-AA alleles tended to exhibit high serum PSA levels (p = 0.0002), poor differentiation (p = 0.0149) and advanced clinical stage (p = 0.0077). These results suggest that the novel polymorphisms identified in the PSA gene promoter may affect transcriptional activity of the PSA gene, and an excess of PSA production may enhance rapid progression of prostate cancer.

Aged↗

PubMedDate not supplied

Hypermethylation does not account for the frequent loss of the retinoic acid receptor beta2 in breast carcinoma.

Hypermethylation of the retinoic acid receptor (RAR) beta2 has been detected in breast cancer cell lines and is known to repress the level of RAR beta2 transcription. RAR beta2 mRNA loss has often been detected in breast cancer tumors, whether promoter region methylation of the RAR beta2 gene accounts for its loss is still unknown. We examined the methylation status of RAR beta2 in breast tumors; 21 out of 50 (42%) breast tumors showed RAR beta2 hypermethylation. RT-PCR analysis showed a complete loss of RAR beta2 mRNA expression in 15 out of 43 (35%) breast tumors. No correlation between the hypermethylation and RAR beta2 loss was found, suggesting that hypermethylation is not fully responsible for the loss of expression of the RAR beta2 gene during breast tumorigenesis.

Aged↗

PubMedDate not supplied

Acquisition of multidrug resistance in recurrent breast cancer demonstrated by the histoculture drug response assay.

Recurrent breast cancer has a very poor response rate to chemotherapy. To understand the degree of acquisition of multidrug resistance in recurrent disease, 24 recurrent breast tumors and 127 primary tumors were evaluated and compared for chemosensitivity in the histoculture drug response assay (HDRA). The evaluation rate was 98.8%. The HDRA utilizes 3-dimensional culture of human tumors on collagen-gel rafts. Doxorubicin (DXR), 5-fluorouracil (5-FU) and mitomycin C (MMC) were tested as standard agents and cisplatin (CDDP) as a candidate agent on surgical specimen of breast cancer in the HDRA. In vitro drug exposure in the HDRA was for 7 days. At the end of the assay, tumor response was assessed by the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The mean inhibition rates of primary tumors vs. recurrent tumors were 57.9% and 38.6% for DXR (p<0.0005); 59.9% and 42.8% for MMC (p<0.01); 49.0% and 33.4% for 5-FU (p<0.01); and 34.5% and 16.0% for CDDP (p<0.005), respectively. The recurrent cases were pretreated clinically with CAF (cyclophosphamide, DXR and 5-FU), CEF (cyclophosphamide, epirubicin and 5-FU) or CMF (cyclophosphamide, methotrexate and 5-FU). In the CAF and CEF group, the HDRA sensitivity to CDDP was significantly lower in recurrent disease (p<0.005) than that of primary breast cancer suggesting that one agent can induce resistance to another. This is further suggested by the fact that 64.7% of the recurrent cases were resistant to all 4 agents tested as opposed to 27% of the primary cases and that only 5.9% of the recurrent cases were sensitive to three or more agents as opposed to 18% of the primary cases. The correlation of the HDRA results to clinical outcome in the study was 80.0% with 15 cases evaluated consisting of 5 true positives, 3 false positives, 7 true negatives and no false negatives. Thus, the HDRA gives useful clinical information, in particular for the specific individualized treatment design necessary to overcome the multidrug resistance problem of recurrent breast cancer.

Adult↗

PubMedDate not supplied

Interstitial irradiation for carcinoma of tongue complicated by chronic renal failure undergoing hemodialysis--a case report.

There has been some controversy concerning dose-time correction in continuous irradiation at low dose rates. We present the results of carcinoma of the tongue in a patient complicated by chronic renal failure, for which he was undergoing hemodialysis three times a week. This patient was treated with a single implant but with a doubling of 137Cs needles for double strength. The actual dose was given in a shorter treatment time than recommended, with the dose-time adjustment following the Paterson-Parker system. The patient has been alive and well for eight years.

Brachytherapy↗