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Biomedical subjects

N Shinohara

Publications and source records attributed to N Shinohara.

At least 37 records · Page 2Linked to original sources
PubMed2000

Suppressive effects of dominant negative ras mutant N116Y on transformed phenotypes of human bladder cancer cells.

To investigate the suppressive effect of dominant negative H-ras mutant N116Y on transformed phenotypes, we established two N116Y ras mutant stable transfectant clones (C5, C13) of human bladder cancer cell line, UMUC-2. These N116Y ras mutant transfectants, especially the C5 cells, showed a dramatic change of cellular morphology and significantly reduced growth in soft agar compared to their control. Furthermore, phosphorylation of the Jun NH2-terminal kinase (JNK) was significantly decreased in these transfectants compared to the control. These results suggest that the N116Y-induced suppression of transformed phenotypes in UMUC-2 cells is associated with inhibition of JNK phosphorylation.

Cell Transformation, Neoplastic↗
PubMed2000

The safety and usefulness of cool head-warm body perfusion in aortic surgery.

OBJECTIVE: To determine the safety and usefulness of antegrade hypothermic cerebral perfusion in conjunction with mild hypothermic (tepid) visceral perfusion (so-called cool head-warm body perfusion; CHWB) in aortic surgery; the clinical outcomes and perioperative data on this new technique were retrospectively analyzed. METHODS: From January 1990 to March 1999, 59 patients underwent ascending aorta or aortic arch surgery using antegrade selective cerebral perfusion (SCP). Three perfusion techniques, differentiated by perfusion temperature, were used, those being deep hypothermia (DH; nasopharyngeal temperature of 20 degrees C, n=14), moderate hypothermia (MH; nasopharyngeal temperature of 28 degrees C, n=17) and CHWB (nasopharyngeal temperature of 25 degrees C and bladder temperature of 32 degrees C, n=28). Selection of the technique largely followed a chronological pattern, in this order: DH, MH and, more recently, CHWB. The three groups were retrospectively compared in terms of operative outcome, duration of cardiopulmonary bypass (CPB) and operation, and intraoperative blood loss. RESULTS: The early (within 30 days after surgery) mortality/hospital mortality (including operative mortality) was 7.1/21.4, 5.9/11.8 and 3.6/7.1% in the DH, MH and CHWB groups, respectively. The rate of stroke was 7.1, 6.3 and 3.6% in the DH, MH and CHWB groups, respectively. No statistical difference was found in early or hospital mortality, or in the rate of stroke among the three groups. The CPB time, especially the time for rewarming, was significantly shorter in the CHWB than in the DH group. Likewise, the operation time, especially the time after CPB, was significantly shorter in the CHWB than in the DH and MH groups. Blood loss was significantly less in the CHWB than in the DH group. CONCLUSION: Our data suggest that CHWB perfusion in aortic surgery is a safe and useful technique in shortening the operation time and reducing blood loss, but further prospective study is necessary.

Aged↗
PubMed2000

An improved intravesical model using human bladder cancer cell lines to optimize gene and other therapies.

Orthotopic implantation of human bladder cancer cells into immunodeficient mice is an important tool for studying the biology and effects of therapy. Nevertheless, the incidence of tumor implantation and growth by transurethral instillation of the human bladder cancer cells into murine bladders has been low or not reproducible. However, using a modified intravesical technique and the human bladder cancer cell lines, KU-7 and UM-UC-2, we have been able to obtain a high and reproducible incidence of superficial bladder tumors. Furthermore, intravesical administration of the LacZ adenovirus vector resulted in significant beta-galactosidase expression in these bladder tumors as well as the normal urothelium, which was associated with the removal of the glycosoaminoglycan layer. Because this modified technique produces a high incidence of superficial human tumor growth and allows the efficacy of gene transfer to be evaluated, it should be a useful model for the study of intravesical gene therapy for human bladder cancer.

Adenoviridae↗
PubMed2000

Significance of the Grb2 and son of sevenless (Sos) proteins in human bladder cancer cell lines.

The epidermal growth factor (EGF) receptor has been suggested to have an important role in tumor initiation and progression of human bladder cancers. Grb2 protein, which is the downstream effector of the EGF receptor, acts as an adaptor protein between the EGF receptor and the Ras guanine-nucleotide exchange factor, son of sevenless (Sos) protein. Sos protein regulates the action of Ras protein by promoting the exchange of GDP for GTP. However, the significance of Grb2 and Sos proteins, which is related to EGF-triggered Ras activation, has not been elucidated in human bladder cancer. The aim of the present study is to clarify the significance of these proteins in human bladder cancer cell lines. In the present study, we used four human bladder cancer cell lines (T24, KU-7, UMUC-2, UMUC-6) and two kinds of cultured normal urothelial cells (HMKU-1, HMKU-2) isolated from patients with no malignancy. We examined the expression of EGF receptor, Grb2, and Sos proteins in these cells by Western blot analysis. Furthermore, the bladder cancer cell lines were subjected to sequence analysis to identify a point mutation in the c-H-ras gene at codon 12. There was no marked difference in the expression of the EGF receptor between human bladder cancer cell lines and cultured normal urothelial cells. On the other hand, expression of Grb2 and Sos proteins was substantially increased in all human bladder cancer cell lines examined in comparison with cultured normal urothelial cells, whether codon 12 of H-ras was mutated or not. These results suggest that the amplification of both Grb2 and SOS proteins plays an important role in the carcinogenesis of human bladder cancer.

Adaptor Proteins, Signal Transducing↗
PubMed2000

The relationship between technical parameters of external beam radiation therapy and complications for localized prostate cancer.

BACKGROUND: This study was performed to review retrospectively the clinical course of chronic rectal bleeding as a complication of external beam radiation therapy for localized prostate cancer and to analyze the relationship between technical parameters of radiation therapy and the complications. METHODS: Seventy-one patients with stages A2, B and C were treated with local-field radiotherapy (total dose 52.5-66 Gy, daily dose 2.0-3.28 Gy, field area 30-81 cm2, number of fields 3-15 ports, planning simulations X-ray or CT-based) between 1989 and 1998 at three institutions. The protocols were consistent during this same period at these institutions. RESULTS: Multivariate analysis revealed pretreatment PSA and Gleason sum to be statistically significant predictors of 5 year prostatic specific antigen (PSA) relapse-free rates in a median follow-up period of 42 months (range 12-119 months). The significant risk factors for higher grading of acute morbidity were a biological equivalent dose, alpha/beta = 10(BED10) > or =65 Gy, dose per fraction > or =3.0 Gy, field area > or =42 cm2, fewer ports and X-ray planning simulation. However, no parameter was associated with higher grading of late morbidity. Eleven patients (15.4%) experienced a late GI complication: grade 1 (4.2%), grade 2 (9.8%), grade 3 (1.4%). The median time to occurrence of rectal bleeding was 12 months after radiotherapy and the mean duration of morbidity was 11 months. CONCLUSIONS: Higher total dose and dose per fraction, larger field area, fewer ports and X-ray simulation increased the grades of acute morbidity. A majority of chronic rectal bleedings were transient and responded to conservative treatment.

Aged↗
PubMed2000

Germ-line mutation analysis in patients with von Hippel-Lindau disease in Japan: an extended study of 77 families.

We have previously reported on the analysis of germ-line mutations in Japanese von Hippel-Lindau disease (VHL) patients and found mutations in 26 families. We have now extended these studies to include an additional 41 VHL families. Germ-line mutation of the VHL gene was screened by DNA-SSCP, direct sequencing, and Southern blot analysis. To summarize all of the data we have studied in this and our previous report, germ-line mutations have been detected in 55 of 77 (73%) (type 1: 41/62 (66%) and type 2: 14/15 (93%)) families. We found similarities in the nature of germ-line mutations including mutational incidence, location, and DNA substitution patterns between Japanese and Western VHL. These similarities may reflect the predominance of endogenous mutational processes. We also found several interesting characteristics in Japanese VHL. Twenty of 41 (49%) intragenic mutations were unique and not reported in the Western VHL. Four mutations (Arg113Stop, Gln132Stop, Leu158Val, and Cys162Tyr) previously characterized as type 1 mutations were identified in the type 2 (with pheochromocytoma) Japanese families. Genotype-phenotype correlation study suggested non-missense mutations predicted to result in the loss of VHL function were associated with the occurrence of renal cell carcinoma, as in sporadic tumors. Our data add to the diversity of VHL germ-line mutations and provide a better understanding of VHL disease in terms of both clinical management and molecular pathogenesis.

Genotype↗
PubMed2000

Incidence and risk factors for subtypes of cerebral infarction in a general population: the Hisayama study.

BACKGROUND AND PURPOSE: We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan. METHODS: Stroke-free subjects (n=1621) aged >/=40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings. RESULTS: The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0. 7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox's proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depression on ECG, glucose intolerance, and smoking in men and left ventricular hypertrophy on ECG and body mass index in women remained significant risk factors for lacunar infarction. ST depression was also significantly related to events of atherothrombotic infarction in women. The risk of atrial fibrillation for cardioembolic infarction was outstandingly high in both sexes, and left ventricular hypertrophy and lower total cholesterol were additional risk factors for cardioembolic infarction in women. CONCLUSIONS: In this Japanese population, lacunar infarction was the most common subtype of cerebral infarction and had a greater variety of risk factors, including not only hypertension but also ECG abnormalities, diabetes, obesity, and smoking, than did atherothrombotic infarction or cardioembolic infarction.

Adult↗
PubMed2000

Three novel PHEX gene mutations in Japanese patients with X-linked hypophosphatemic rickets.

X-linked hypophosphatemic rickets (XLH) is an X-linked dominant disorder characterized by renal phosphate wasting, abnormal vitamin D metabolism, and defects of bone mineralization. The phosphate-regulating gene on the X-chromosome (PHEX) that is defective in XLH has been cloned, and its location identified at Xp22.1. It has been recognized to be homologous to certain endopeptidases. So far, a variety of PHEX mutations have been identified mainly in European and North American patients with XLH. To analyze the molecular basis of four unrelated Japanese families with XLH, we determined the nucleotide sequence of the PHEX gene of affected members. We detected a new nonsense mutation (R198X) in exon 5, a new 3 nucleotides insertion mutation in exon 12 and a new missense mutation (L160R) in exon 5 as well as a previously reported nonsense mutation in exon 8 (R291X). These results suggest that: 1) PHEX gene mutations are responsible for XLH in Japanese patients, and 2) PHEX gene mutations are heterogeneous in the Japanese population similarly to other ethnic populations.

Adult↗
PubMed2000

Effects of monosodium glutamate-induced obesity in spontaneously hypertensive rats vs. Wistar Kyoto rats: serum leptin and blood flow to brown adipose tissue.

We compared the effects of hypothalamic obesity induced by neonatal monosodium glutamate (MSG) treatment between spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Newborn WKY and SHR were injected intraperitoneally with 4 mg/kg body weight of MSG daily for 5 days. At 6 months of age, the obesity of SHR was more advanced than that of WKY, but at 14 months of age the severity of obesity was similar between the two strains. Hypertriglyceridemia was enhanced in MSG-treated SHR as compared with MSG-treated WKY. Systolic blood pressure measured by the tail-cuff method was consistently lower in MSG-treated SHR than in control SHR, whereas blood pressure was not affected by neonatal MSG treatment in WKY. Food restriction reduced body weight more in control SHR than in control WKY, with the former also showing enhanced ketogenesis. Neonatal MSG treatment abolished the accelerated reduction of body weight in SHR. Serum leptin concentration was markedly increased in MSG-treated obese rats, though no differences were seen between WKY and SHR in the control or MSG-treated groups. Serum leptin was closely correlated with both Lee obese index and mesenteric fat weight over the strain. Blood flow in interscapular brown adipose tissue (BAT) measured by Laser Doppler flowmetry was significantly increased in response to beta3-adrenoceptor agonist BRL26830A in both the control and MSG-treated rats. However, the response of blood flow was not affected by MSG treatment or strain difference. The present study demonstrated some strain differences in response to neonatal MSG treatment between WKY and SHR. These differences could not be explained by the difference in serum leptin level or beta3-adrenergic reactivity in BAT.

Adipose Tissue, Brown↗
PubMed2000

Gonadotropin-releasing hormone analog therapy failed to improve predicted final height in two children with central precocious puberty and microcephalus.

Long-acting gonadotropin-releasing hormone (GnRH) analog treatment for central precocious puberty (CPP) suppresses excessive bone maturation by inhibiting the pituitary-gonadal axis, and usually assures favorable results for growth potential. Recently, we encountered two children with CPP and microcephalus in whom GnRH analog therapy arrested pubertal development, but could not suppress bone age maturation effectively. Eventually, their final height deteriorated rather than improved. The reason why these two cases did not respond to GnRH analog therapy remains unknown. However, microcephalus and minor cerebral anomalies may have some links to deterioration of final height. Our cases suggest that careful evaluation will be required especially for CPP with microcephalus throughout treatment with GnRH analog.

Adolescent↗
PubMed2000

A method for evaluating color stability of light-cured composite resins using an experimental filter.

The purpose of this study was to investigate a method for evaluating color stability of light-cured composite resins using an experimental filter that simulates human enamel. The light transmission coefficients and their spectral distributions from 400 to 600 nm of twelve enamel specimens were measured. The experimental filter was designed so that its light transmittance characteristics were similar to those of enamel. Color stability tests for ten shades of two light-cured composite resins, which were irradiated directly and indirectly through the experimental filter with a light source, were performed. Despite different irradiation procedures, most materials exhibited significant color changes in the color stability test. Although the differences were small, the group of specimens irradiated indirectly through the filter showed significantly higher color differences in comparison with those irradiated directly. Our results indicate that the light attenuating effect of enamel affects the color stability of light-cured composite resins.

Color↗
PubMed1999

Novel missense mutation (Leu466Arg) of the DAX1 gene in a patient with X-linked congenital adrenal hypoplasia.

We identified a DAX1 missense mutation, a substitution of arginine for leucine at codon 466 (Leu466Arg), in an infant with X-linked congenital adrenal hypoplasia (AHC). A heterozygous substitution, Leu466Arg, was also identified in his mother and sister. Since leucine at position 466 is well conserved among other orphan nuclear hormone receptor superfamilies and Leu466Arg was not detected among 50 normal Japanese control individuals, the mutation is most likely responsible for X-linked AHC. It is interesting to note that Leu466Arg among all mutations ever reported is located at the most C-terminal region of the DAX-1 protein. Most mutations identified previously were located in the C-terminal presumptive ligand binding domain. Hence, the C-terminal end of the DAX-1 protein may play an important role in the biological function, such as in normal adrenal embryogenesis.

Adrenal Insufficiency↗
PubMed1999

Severe impairment of B cell function in lpr/lpr mice expressing transgenic Fas selectively on B cells.

Transgenic lpr/lpr mice expressing functional Fas selectively on B cells were produced in an attempt to elucidate the role of Fas on B cells in the regulation of autoantibody production. The homozygous lpr/lpr mice carrying the transgene did not produce anti-double-stranded DNA antibodies throughout their lives, whereas the development of abnormal lpr T cells (double negative, B220(+)) was not suppressed. Further analyses, however, revealed that the expression of the transgenic Fas on B cells of lpr/lpr homozygous mice resulted in severe impairment of the B cell function. The defect was characterized by a decrease in the number of mature peripheral B cells, a reduction in the serum Ig level and the total failure of B cells to mount antibody responses to stimulations of T-dependent as well as T-independent antigens. Such a defect was prominent only when the transgene was expressed on the lpr/lpr homozygous background. On the contrary, B cells of the transgenic lpr/lpr mice were shown to be capable of producing Ig when stimulated with anti-CD40 in the presence of IL-4 and IL-5. Furthermore, lpr/lpr T cells showed enhanced non-specific cytolytic activity. These observations suggested that the observed B cell defect was probably attributable to the destruction of activated B cells expressing transgenic Fas by aggressive lpr/lpr T cells.

Animals↗