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Biomedical subjects

S Aoki

Publications and source records attributed to S Aoki.

At least 73 records · Page 4Linked to original sources
PubMed2001

Free vascularized fibular graft vs. Ilizarov method for post-traumatic tibial bone defect.

From 1991 to 1996, four free vascularized fibular grafts (FVFG) and four callus distraction (CD) techniques were performed for post-traumatic tibial defects at the authors' institute. They attempted to discern any differences of results between FVFGs and CDs for post-traumatic tibial defects. The mean defect length of the FVFG and CD groups were 7.3 cm and 4.6 cm, respectively (p < 0.05). They selected as contributing factors: external fixation time, complication rate, hospital charge, union rate, and functional score (Puno's criteria), in order to compare the treatment of FVFG with that of CD. The external fixation times of the FVFG and CD groups were 176 days and 261 days, respectively. One septic non-union after refracture of the grafted fibula occurred in the FVFG group. Two non-unions (50 percent) at the docking site occurred in the CD group. The mean total costs of the FVFG and CD groups were 7,398,536 yen (US $68,505) and 11,798,153 yen(US $109,242), respectively. The union rates of both groups were 75 percent and 100 percent, respectively. The mean functional scores of both groups were 69.5 and 88.8 points, respectively. The functional results of the FVFG group were as follows: one patient showed good results; one, fair; and two, poor. The functional results of the CD group were as follows: two patients showed excellent results; one, good; and one, fair. Both the costs and the functional outcomes between the two groups did not significantly differ. No clear differences between the two treatment groups could be determined. However, many more cases are needed to establish statistically significant differences between both methods.

Accidents, Traffic↗
PubMed2001

A solid cystic tumor of the pancreas with ossification and possible malignancy, coexisting nonfusion of the pancreatic ducts.

We report the case of a 34-year-old woman with a solid cystic tumor (SCT) of the pancreas accompanied by ossification and possible malignancy, coexisting nonfusion of the pancreatic ducts. There was a 24 x 29 x 33-mm mass with a prominent calcified lesion in the tail of the pancreas detected by abdominal ultrasonography, computed tomography, and magnetic resonance imaging. There were no distal metastases detected. Endoscopic retrograde pancreatography revealed nonfusion of the pancreatic ducts. The resected tumor consisted of solid and cystic components. The tumor was not encapsulated and included a severely ossified lesion inside. On microscopy, the tumor cells were small, eosinophilic, and proliferated in a solid or pseudo-papillary pattern. The tumor cells infiltrated into the surrounding normal pancreas parenchyma and invaded part of the mesentery. The immunostaining was positive for alpha-1-antitrypsin, neuron-specific enolase, vimentin, and chromogranin A. In the literature, only a few cases of SCT of the pancreas described ossification. As far as we know, only three cases of SCT of the pancreas, which demonstrated nonfusion of the pancreatic ducts, have been reported. Thus, SCT of the pancreas with ossification, possible malignancy, and coexisting nonfusion of the pancreatic ducts is extremely rare.

Adult↗
PubMed2001

An exact test for the association between the disease and alleles at highly polymorphic loci with particular interest in the haplotype analysis.

The association analysis between the disease and genetic alleles is one of the simple methods for localizing the susceptibility locus in the genes. For revealing the association, several statistical tests have been proposed without discussing explicitly the alternative hypotheses. We therefore specify two types of alternative hypotheses (i.e., there is only one susceptibility allele in the locus, and there is an extension or shortening of alleles associated with the disease) and derive exact tests for the respective hypotheses. We also propose to combine these two tests when the prior knowledge is not sufficient enough to specify one of these two hypotheses. In particular, these ideas are extended to the haplotype analysis of three-way association between the disease and bivariate allele frequencies at two closely linked loci. As a by-product, a factorization of the probability distribution of the three-way cell frequencies under the null hypothesis of no three-way interaction is obtained.

Algorithms↗
PubMed2001

Reversing effect of agosterol A, a spongean sterol acetate, on multidrug resistance in human carcinoma cells.

The effect of agosterol A, a novel polyhydroxylated sterol acetate isolated from a marine sponge, on P-glycoprotein (P-gp)-mediated multidrug-resistant cells (KB-C2) and the multidrug resistance associated protein (MRP1)-mediated multidrug-resistant cells (KB-CV60) was examined. Agosterol A reversed the resistance to colchicine in KB-C2 cells and also the resistance to vincristine in KB-CV60 cells at 3 to 10 microM concentration. Agosterol A at 3 mM increased the vincristine concentration in both KB-C2 cells and KB-CV60 cells to the level in parental KB-3-1 cells. Agosterol A also decreased the efflux of vincristine from both KB-C2 cells and KB-CV60 cells to the level seen in KB-3-1 cells. Agosterol A inhibited the [(3)H]azidopine-photolabeling of P-gp and also inhibited the uptake of [(3)H]S-(2,4-dinitrophenyl)glutathione (DNP-SG) in inside-out membrane vesicles prepared from KB-CV60 cells. We conclude that agosterol A directly inhibited drug efflux through P-gp and/or MRP1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Contribution of heat transfer to turbine blades and vanes for high temperature industrial gas turbines. Part 1: Film cooling.

This paper deals with the contribution of heat transfer to increase the turbine inlet temperature of industrial gas turbines in order to attain efficient and environmentally benign engines. High efficiency film cooling, in the form of shaped film cooling and full coverage film cooling, is one of the most important cooling technologies. Corresponding heat transfer tests to optimize the film cooling effectiveness are shown and discussed in this first part of the contribution.

Journal Article↗
PubMed2001

Contribution of heat transfer to turbine blades and vanes for high temperature industrial gas turbines. Part 2: Heat transfer on serpentine flow passage.

The improvement of the heat transfer coefficient of the 1st row blades in high temperature industrial gas turbines is one of the most important issues to ensure reliable performance of these components and to attain high thermal efficiency of the facility. This paper deals with the contribution of heat transfer to increase the turbine inlet temperature of such gas turbines in order to attain efficient and environmentally benign engines. Following the experiments described in Part 1, a set of trials was conducted to clarify the influence of the blade's rotating motion on the heat transfer coefficient for internal serpentine flow passages with turbulence promoters. Test results are shown and discussed in this second part of the contribution.

Journal Article↗
PubMed2001

Role of T cells in development of chronic pancreatitis in male Wistar Bonn/Kobori rats: effects of tacrolimus.

We assessed T cell association with acinar cell apoptosis and a preventive effect of tacrolimus, a T cell suppressant, on the development of chronic pancreatitis in male Wistar Bonn/Kobori rats. At 15 wk, cellular infiltrates composed of F4/80-positive cells (monocytes/macrophages), CD4-positive cells, and CD8-positive cells were extensive in the interlobular connective tissue and parenchyma. In particular, CD8-positive cells invaded pancreatic lobules and formed close associations with acinar cells, some of which demonstrated features of apoptosis. At 20 wk, CD8-positive cells were still abundant in the fibrotic tissue formed with loss of acinar cells. Repeated subcutaneous injection of 0.1 mg x kg(-1) x day(-1) but not 0.025 mg x kg(-1) x day(-1) of tacrolimus for 10 wk completely prevented the occurrence of acinar cell apoptosis, infiltration of CD4- and CD8-positive cells, and development of pancreatitis at the age of 20 wk, but these maneuvers did not recover the decreased plasma corticosterone levels, which may be responsible for the development of disease. We demonstrated that T cells, possibly CD8-positive cells, are involved in inducing apoptosis of acinar cells, raising the possibility that tacrolimus might find clinical application in the treatment of autoimmune chronic pancreatitis.

Animals↗
PubMed2001

Protective effect of fluvastatin on degradation of apolipoprotein B by a radical reaction in human plasma.

Fluvastatin, which is a synthetic 3-hydroxy-3-methylglutaryl coenzyme (HMG-CoA) reductase inhibitor, its metabolites (M2, M3 and M4) and trolox all inhibited the decrease of apolipoprotein B-100 (apoB) and alpha-tocopherol in a radical reaction of human plasma initiated by Cu2+. The concentrations of fluvastatin, M2, M3, M4 and trolox for 50% inhibition (IC50) of apoB fragmentation were 405, 8.55, 1.75, 305, and 43.4 microM, respectively. The IC50 value of pravastatin, which is another HMG-CoA reductase inhibitor, was 2880 microM, showing that pravastatin is not an effective antioxidant. Although fluvastatin, its metabolites and trolox inhibited the decrease of alpha-tocopherol in a similar manner to that of apoB, pravastatin did not significantly inhibit the decrease of alpha-tocopherol. Since oxidation of low density lipopotein (LDL) is an important step in the initiation and progression of atherosclerosis, fluvastatin may reduce the risk of atherosclerosis not only by lowering plasma cholesterol but also by protecting LDL from oxidation.

Anticholesteremic Agents↗
PubMed2001

Influence of sugar chain on fibrin affinity of recombinant t-PA.

The role of the sugar chain on the fibrin affinity property of tissue plasminogen activator (t-PA) was investigated using two variants of wild type t-PA (WT t-PA I and WT t-PA II) and mutant type t-PA (mt-PA ; Gln117 t-PA I and Gln117 t-PA II), whose sugar chains have different structures. In terms of fibrin affinity, Gln117 t-PA was higher than WT t-PA ; moreover, Type II was higher than Type I. Bindings mediated via finger domain (F mode) and kringle 2 domain (K2 mode) were distinguished using epsilon-amino caproic acid (EACA). Consequently, F mode and K2 mode bindings were inhibited by the sugar chains at Asn117 and 184, respectively. These results were assumed to be due to the steric hindrance of the sugar chains.

Aminocaproic Acid↗
PubMed2001

Novel neuronal nitric oxide synthase (nNOS) selective inhibitor, aplysinopsin-type indole alkaloid, from marine sponge Hyrtios erecta.

Two novel aplysinopsin-type indole alkaloids, 1 and 2, and three known indole alkaloids were isolated from the marine sponge Hyrtios erecta. These compounds exhibited selective inhibitory activity against the neuronal isozyme of nitric oxide synthase (nNOS). Furthermore, new quinolone 7 was also isolated from the same marine sponge. The chemical structures of these new compounds were elucidated on the basis of spectroscopic analysis.

Animals↗
PubMed2001

The genetic factor in acute myocardial infarction with hypertension.

This study assessed the contribution of polymorphisms of angiotensin II (AngII) receptors and bradykinin B2 (BK-B2) receptor to hypertension and acute myocardial infarction (AMI) in a Japanese population: 150 subjects with essential hypertension, 150 subjects with AMI with/without hypertension, and 150 healthy, age- and sex-matched controls. Polymorphisms of the AngII type 1 receptor (1166 A/C) and type 2 receptor (3123 C/A), and the BK-B2 receptor (-58T/C, exon 1) were analyzed and significant differences of genotypes and allelic frequencies in the AngII type 2 receptor C/A and BK-B2 receptor -58T/C were found between the essential hypertension and control subjects. Further, a significantly higher incidence of the C allele of the BK-B2 receptor was seen in AMI subjects with hypertension compared with those without hypertension. Genetic variations in the AngII and BK-B2 receptors could prove to be significant pathophysiological mechanisms affecting essential hypertension and AMI, and genetic differences appear to be a new risk factor for these conditions.

Adult↗
PubMed2001

Genetic background in patients with acute myocardial infarction.

The renin-angiotensin system is believed to play important roles in the development of acute myocardial infarction, and gene polymorphisms may also be involved. To investigate the genetic background in patients with acute myocardial infarction, we performed a case control study in a Japanese population. The study included 150 patients with acute myocardial infarction and 150 healthy, age- and sex-matched controls. We examined polymorphisms of angiotensin II type 1 receptor (1 166 A / C), type 2 receptor (3123 C / A), and bradykinin B2 receptor (-58 T / C) in these subjects. The allelic frequencies of angiotensin II type I receptor C and angiotensin II type 2 receptor A were significantly higher in the acute myocardial infarction subjects than in the control subjects, and this tendency was more significant in the younger patients. The combined ratios of angiotensin II type 1 receptor C and type 2 receptor A alleles in patients under 64 years old were significantly higher than in their older counterparts. However the total numbers of conventional coronary risk factors (hypertension, hypercholesterolemia, diabetes mellitus, and smoking) in individual subjects were not significantly different between younger and older patients. These polymorphisms were found to be involved in the development of acute myocardial infarction, particularly in the younger patients, and it was concluded that the incidence of acute myocardial infarction might be reduced by management from the genotypes.

Aged↗
PubMed2001

[Autoimmune hepatitis associated with mixed connective tissue disease: report of a case and a review of the literature].

A case is reported of a 29 year old female who had autoimmune hepatitis associated with mixed connective tissue disease (MCTD). The patient developed MCTD at the age of 19, and was treated with prednisolone. Liver dysfunction developed 7 years later, which exacerbated shortly after the patient suffered intrauterine fetal death during the second trimester of pregnancy. Laboratory data showed negative anti-hepatitis C antibody and hepatitis B antigen, but positive anti-smooth muscle antibody. A liver biopsy showed chronic active hepatitis. Referring to the criteria we diagnosed her as having autoimmune hepatitis. Although hepatomegaly is sometimes observed in MCTD patients, only 5 cases of autoimmune hepatitis associated with MCTD have been reported in the past. In our case, it is of note that autoimmune hepatitis developed while symptoms of MCTD were in remission, and that autoimmune hepatitis exacerbated with the emergence of anti-smooth muscle antibody following the termination of pregnancy.

Adult↗
PubMed2001

Lifestyle and sociodemographic risk factors for death among middle-aged and elderly residents in japan from a five-year follow-up cohort study.

To examine the relationship between lifestyle and sociodemographic risk factors and mortality, a population-based prospective cohort study was conducted in two areas of Gunma Prefecture, Japan, and a cohort consisting of 11,565 subjects aged 40-69 at baseline in 1993 was followed. During the five-year follow-up period, 201 men and 103 women died. The relative risks (RRs) of risk factors were estimated by the Cox proportional-hazards model. Significant RRs with multivariate adjustment for all-cause mortality was observed for body mass index (BMI). The curve for the relationship between BMI and all-cause mortality was L-shaped in men and U-shaped in women, with the lowest RRs at a BMI of 22-25 in both men and women. Other significant RRs for all-cause mortality were observed for obesity in the subjects' 30's in both men and women (RR: 2.42 and RR: 2.75), poor perceived health status in men (RR: 4.55), and having had a health examination in the past three years in both men and women (RR: 0.49 and RR: 0.46). These results suggested that increased risk of death was independently associated with a lower BMI, obesity in the subjects' 30's, and not undergoing health examinations, among both men and women, and poor perceived health status among men.

Adult↗
PubMed2001

[Clinical efficacy of leuprolide acetate and combined treatment with estramustine for advanced prostate cancer].

BACKGROUND/PURPOSE: Twenty-two institutes have organized Keio University Prostate Cancer Study Group to study clinical efficacy and safety of Leuprolide acetate (Leuplin) for the treatment of advanced prostate cancer (clinical stage D1 and D2). Cotreatment of Leuplin and Estramustine phosphate disodium (Estracyt) has been performed to investigate its clinical efficacy. MATERIALS AND METHODS: One hundred and two cases of advanced prostate cancer were treated either with Leuplin alone (group I), Leuplin and Estracyt (group II) or Estracyt alone (group III). After 12 weeks treatment, clinical effects against subjective symptoms (pain, voiding difficulty, performance status and body weight), serum testosterone level, tumor size and serum PSA level were examined to investigate short-term effect of each treatment. The treatment had been continued for 24 months and the treatment effects including progression free survival and overall survival were analyzed. RESULTS: Clinical efficacy after 12 weeks treatment were examined among 97 cases (group I; 35 cases, group II; 36 cases, group III; 26 cases). The background of those patients in each group was statistically equal. Treatment effects against subjective symptoms and serum testosterone level statistically revealed no significant difference among 3 groups. Treatment effects against primary tumor, bone metastatic lesion, lymphnode metastatic lesion and serum PSA level were investigated and anti-tumor effect was characterized by total efficacy rate (complete remission rate plus partial remission rate) of each treatment group. Treatment efficacy rates for each lesion and PSA demonstrated no statistical difference among 3 treatment groups. Total efficacy rate of group I, II and III were 88.2%, 84.0% and 78.3%, respectively, which statistically revealed no significant difference. Total efficacy rate of each group after completing 24 months treatment was; group I 80.0%, group II 55.6% and group III 83.3%, which statistically showed no significant difference among 3 treatment groups. The median day for progression free survival of group I, II and III were 661, 731 and 517, respectively. The overall survival rate of group I, II and III after completing 24 months treatment were 77.5%, 83.0% and 72.4%, respectively. Both progression free survival rates and overall survival rates revealed no significant difference among 3 groups. Side effects during 24 months treatment were seen in 8.6% of group I, 47.2% of group II and 26.9% of group III, and these occurrence rates were significantly different among the groups (p = 0.0013). CONCLUSION: Although number of the cases had not been able to continue the treatment for their side effects, the statistical characterization demonstrated that cotreatment of Leuplin and Estracyt had no greater treatment effect than monotreatment of each drug.

Aged↗
PubMed2001

[A case of transitional cell carcinoma of the bladder in a juvenile patient].

A 15-year-old male was referred to our hospital with the chief complaint of gross hematuria. Cystoscopic examination revealed a papillary tumor on the posterior wall. Transurethral resection of the bladder tumor was performed. Histological examination of the excised tumor showed transitional cell carcinoma, grade 1, pTa. Recurrence has not been observed for about 2 years after the operation. We investigated 54 previously reported Japanese cases of bladder cancer before age twenty including the present case.

Adolescent↗
PubMed2001

[Presynaptic effects of botulinum toxin type A on the neuronally evoked response of albino and pigmented rabbit iris sphincter and dilator muscles].

PURPOSE: To investigate the effects of botulinum toxin type A(botulinum A toxin) on the autonomic and other non-adrenergic, non-cholinergic nerve terminals. METHODS: The effects of neurotoxin on twitch contractions evoked by electrical field stimulation (EFS) were studied in isolated rabbit iris sphincter and dilator muscles using isometric tension recording. RESULTS: Botulinum A toxin(150 nM) inhibited the fast cholinergic and slow substance P-ergic component of contraction evoked by EFS in the rabbit iris sphincter muscle without affecting the response to carbachol and substance P. Botulinum A toxin(150 nM) did not affect the twitch contraction evoked by EFS in the rabbit iris dilator muscle. CONCLUSION: These data indicated that botulinum A toxin may inhibit not only the acetylcholine release in the cholinergic nerve terminals, but also substance P release from the trigeminal nerve terminals of the rabbit iris sphincter muscle. However, neurotoxin has little effect on the adrenergic nerve terminals of the rabbit iris dilator muscle.

Animals↗