Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 109 records · Page 6Linked to original sources

PubMed2000

Craniocervical and aortic atherosclerosis as neurologic risk factors in coronary surgery.

BACKGROUND: Advanced age is associated with increased systemic atherosclerosis and is a consistent neurologic risk factor after coronary artery bypass grafting (CABG). METHODS: We studied prospectively whether varying degrees of a total atherosclerotic score derived from the brain, carotid arteries, and ascending aorta predicted postoperative neuropsychologic (NP) dysfunction and stroke in 177 elderly patients (> or = 60 years) undergoing CABG. RESULTS: Group L (low total atherosclerotic score) had rates of NP dysfunction of 25% and 4%, group I (intermediate) had rates of 33% and 22%, and group H (high) had rates of 79% and 43% on postoperative days 1 and 7, respectively (p < 0.001). The incidence of stroke was higher in group H (14.3%) than in groups I and L (7.8% and 0.9%; p = 0.013). Stepwise logistic regression analysis demonstrated the significant predictors of NP dysfunction on postoperative day 7 to be total atherosclerotic score, peripheral vascular disease, and diabetes mellitus, and those of stroke to be total atherosclerotic score, peripheral vascular disease, and hyperlipidemia. CONCLUSIONS: Perioperative evaluation of craniocervical and aortic atherosclerosis is useful to identify a high-risk patient at postoperative NP dysfunction and stroke after CABG.

Aged↗

PubMed2000

Differentiation of mechanism and prognosis of traumatic brain stem lesions detected by magnetic resonance imaging in the acute stage.

We retrospectively evaluated the MRI from 17 patients with primary brain stem injury obtained in the acute stage. Clinical and radiological findings were analyzed in these 17 patients. T2-weighted imaging proved to be most sensitive and specific for the diagnosis of primary brain stem injury. We found two patterns of brain stem injury. The good prognosis group showed ventral brain stem lesions or dorsal superficial brain stem lesions. On the other hand the poor prognosis group showed deep dorsal brain stem lesions. These acute stage findings are seen only temporally in many cases so that it is most important to examine MRI findings in the acute stage to evaluate the prognosis of the patient. MRI was valuable in predicting the outcome. The possible mechanism of brain stem injury in patients with head injury is briefly discussed.

Acute Disease↗

PubMed2000

Potent in vivo antimalarial activity of 3,15-di-O-acetylbruceolide against Plasmodium berghei infection in mice.

The antimalarial activity of the O-acylated bruceolide derivative, 3,15-di-O-acetylbruceolide, was evaluated against Plasmodium berghei in vivo. The concentration of 3,15-di-O-acetylbruceolide required for 50% suppression (ED50) of P. berghei in mice was 0.46 +/- 0.06 mg/kg/day, whereas bruceolide was only half as effective as 3,15-di-O-acetylbruceolide. Two antimalarial drugs used clinically, chloroquine and artemisinin, demonstrated only low activity corresponding to 1/4 and 1/12 of the ED50 value of 3,15-di-O-acetylbruceolide, respectively. These results may be helpful in the design of better chemotherapeutic bruceolides against falciparum malaria.

Animals↗

PubMed2000

Effects of various decalcification protocols on detection of DNA strand breaks by terminal dUTP nick end labelling.

To analyse DNA strand breaks by terminal deoxy(d)-UTP nick-end labelling (TUNEL) in calcified tissues including bones and teeth, it is important to decalcify the tissues first. However, the effects of decalcifying reagents on the integrity of DNA are largely unknown. In the present study, we evaluated the usefulness of various decalcifying reagents including 10% EDTA (pH 7.4), 5% trichloroacetic acid (TCA), 5% formic acid, 5% HCl, 10% nitric acid, Plank-Rychlo's solution, Morse's solution and K-CX solution in TUNEL staining. Mouse maxilla was selected as the experimental system. Apoptotic cells naturally occurring in the epithelium were analysed. Tissues were assessed by soft X-ray imaging to confirm complete decalcification. The time required for decalcification of the tissue was 7 days with 10% EDTA and 2 days with other decalcifiers. Decalcified tissues were stained with Methyl/Green-Pyronine Y or 4',6-diamidino-2-phenylindole for assessment of DNA integrity. Nuclei of epithelial cells were strongly positive for both dyes after decalcification with 10% EDTA, 5% TCA, Morse's solution and 5% formic acid. The other reagents failed to retain DNA. Our results demonstrated good TUNEL staining of the maxilla treated with 10% EDTA or 5% TCA. Based on the required time for processing and the signal-noise ratio, we recommend 5% TCA as the decalcifying reagent to analyse for DNA strand breaks.

Animals↗

PubMed2000

Cyclooxygenase-2 overexpression correlates with tumour recurrence, especially haematogenous metastasis, of colorectal cancer.

Epidemiological studies have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs), known to inhibit cyclooxygenase (COX), reduce the risk of colorectal cancer. COX is a key enzyme in prostaglandin biosynthesis, and two isoforms of COX, COX-1 and COX-2, have been identified. Recently COX-2 has been reported to frequently overexpress in colorectal neoplasms and to play a role in colorectal tumorigenesis and tumour progression. In this study, using immunohistochemistry, we examined COX-2 expression in advanced human colorectal cancer and its correlation with clinicopathological features. COX-2 expression was observed mainly in the cytoplasm of cancer cells in all the specimens examined, but some stromal cells and endothelial cells were also stained. According to the grade of COX-2 expression of the cancer cells, patients were divided into high- and low-COX-2 expression groups. High-COX-2 expression significantly correlated with tumour recurrence, especially haematogenous metastasis. These results suggest that a selective COX-2 inhibitor can be a novel class of therapeutic agents not only for tumorigenesis but also for haematogenous metastasis of colorectal cancer. To our knowledge, this is the first report on the correlation between COX-2 overexpression and recurrence of colorectal cancer.

Aged↗

PubMed2000

Esophageal achalasia in pregnancy.

Achalasia is rare motor disorder of esophageal smooth muscle. It has been linked to malnutrition during pregnancy leading to maternal and fetal mortality. We report a case of achalasia with intrauterine fetal death who succeeded in following pregnancy with good fetal and maternal outcome after operative treatment. A 34-year-old pregnant woman had intrauterine fetal death at 27 gestational weeks due to severe and persistent maternal malnutrition during pregnancy. Achalasia was diagnosed postpartum and myotomy-fundoplasty was performed. She succeeded in normal delivery with a healthy baby 21 months after the operation. This case suggests the effect of severe achalasia of early onset on poor fetal outcome, and the efficacy of surgical myotomy for the improvement of following pregnant outcome.

Adult↗

PubMed2000

Endoscopic observation of squamous metaplasia of the stomach: a report of two cases.

Squamous metaplasia of the stomach is a rare clinical entity that occurs during healing of gastric ulcers or chronic inflammation. We have treated two patients with this condition, which has only occasionally been observed endoscopically. The first was a 60-year-old woman who initially presented with multiple gastric ulcers. Two months after treatment, a white patch about 4 cm in diameter was found in the lesser curvature of the cardiac region of stomach. The second patient was a 65-year-old woman, who also developed a white patch in the same region. Two months later, a small ulcer and inflamed mucosa were seen near the lesion. The white areas in both patients were stained with Lugol's iodine solution, and biopsy specimens confirmed squamous epithelium. The squamous metaplasia was observed as a white mucosal area in the stomach, and the metaplastic area stained positively with Lugol's iodine solution.

Aged↗

PubMed2000

Administration of human chorionic gonadotropin with a controlled-release function to immature rats for application in male infertility therapy.

Biodegradable poly(DL-lactic acid) (PLA) devices with controlled release of human chorionic gonadotropin (hCG) were fabricated in a 2-mm cylinder form by the meltpressing technique. The devices fabricated were inserted subcutaneously in the backs of immature rats. It was found that the serum level of testosterone (T) remained constant at approximately 0.7 ng/ml for an experimental period of 14 days, resulting in greater Leydig cell production of testosterone. This was also suggested from the results of immunohistochemical observation of the testis and weight changes of prostates, such as the ventral prostates and seminal vesicle.

Absorbable Implants↗

PubMed2000

EAT-20, a novel transmembrane protein with EGF motifs, is required for efficient feeding in Caenorhabditis elegans.

The pharynx of Caenorhabditis elegans is a neuromuscular organ responsible for feeding, concentrating food by its pumping movement. A class of mutants, the eat mutants, are defective in this behavior. We have identified a novel eat gene, eat-20, encoding a unique transmembrane protein with three EGF motifs. Staining with a specific polyclonal antibody reveals that EAT-20 is expressed predominantly in the pharyngeal muscles and a subset of neurons. Some hypodermal cells also express EAT-20. eat-20 mutant animals are starved, have smaller brood sizes, and have prolonged egg-laying periods. The starvation apparently results from pharyngeal pumping defects, including a reduced pumping rate and "slippery pumping," in which the contents of the pharynx sometimes move rostrally. However, electrical activity of eat-20 mutants appears normal by electropharyngeogram.

Amino Acid Sequence↗

PubMed2000

Echocardiographic and pathological evaluation of atherosclerosis in the ascending aorta during coronary artery bypass grafting.

UNLABELLED: We performed intraoperative echocardiography with an epiaortic probe to assess the correlation between echocardiographic appearance and pathological findings of the aorta and to examine the effect of cross-clamping on the aortic wall in 276 patients who underwent coronary artery bypass grafting. The ascending aorta was divided into three segments as follows: lower (L), upper (U), and innominate. The anterior (ant) and posterior (post) intimal thicknesses of each of the three segments were measured. The echogenicity at each of the six locations was examined and was classified as isoechoic or nonisoechoic (hyperechoic, hypoechoic, or mixed type). Tissue punched from the ant L wall of the ascending aorta for vein anastomosis was examined for the presence of atheroma. At the ant L, the prevalence of atheroma was significantly higher in nonisoechoic walls than in isoechoic walls (P = 0.049). We divided patients into two groups according to echogenicity at the U segments. Group A (n = 213) consisted of patients whose echogenicities at both ant U and post U were isoechoic. Group B (n = 63) consisted of patients with nonisoechoic echogenicity at ant U and/or post U. The intimal thicknesses at all six locations in Group B patients were greater than those of Group A (P < 0.01). Deformities at the clamp site after cardiopulmonary bypass were observed significantly more often in Group B than in Group A (P < 0.01). Our data suggest that a nonisoechoic aortic wall indicates more advanced atheroma and a higher risk of deformities at the clamp site. Examination of the echogenicity of the ascending aorta may be one method to reduce perioperative neurological complications. IMPLICATIONS: We performed epiaortic echocardiography during coronary artery bypass grafting and found that the presence of atheroma and deformities at the cross-clamping site were significantly more prevalent in nonisoechoic walls than isoechoic walls.

Aged↗

PubMed2000

Radiocesium in children residing in the western districts of the Bryansk Oblast from 1991-1996.

Measurements of 137Cs body burden were carried out in 1991-1996 for children residing in the western part of Bryansk Oblast (Russia) where area contamination with 137Cs following the Chernobyl accident varied from 0.03-3.7 MBq m(-2). The mean and median values of 137Cs specific activity (SA) in the bodies of children 5-15 y old for the whole period of surveillance averaged for 26,029 measurements was 85 Bq kg(-1) and 49 Bq kg(-1), respectively. Mean values in different places of residence varied from 30-342 Bq kg(-1) for the settlements where the number of examinees was not less than 50. There is a moderately strong relationship between mean SA in the settlement and the level of area contamination with 137Cs. A strong seasonal effect on 137Cs body burden was found. The ratio of average SA values is 1:1.75 for spring to autumn 1992-1995 in the settlement where the largest number of children was examined. This effect might be attributed to a seasonal change in diet. Based on questionnaire information on individual consumption of locally produced foods, the descending rank of contribution of food items to 137Cs intake by children was found to be: meat-mushrooms-milk-vegetables. Assuming that the dose distribution would follow the distribution of SA values, internal doses to the whole body from ingested 137Cs were assessed. The mean value of annual internal dose averaged for the whole set of measurements is 0.21 mSv, and the median of the individual dose distribution is 0.12 mSv y(-1) For 2% of the total sample the annual dose exceeded 1 mSv, with the highest individual dose being 9 mSv in 1994 for a 7-y-old girl.

Adolescent↗

PubMed2000

Normalization and subtraction of cap-trapper-selected cDNAs to prepare full-length cDNA libraries for rapid discovery of new genes.

In the effort to prepare the mouse full-length cDNA encyclopedia, we previously developed several techniques to prepare and select full-length cDNAs. To increase the number of different cDNAs, we introduce here a strategy to prepare normalized and subtracted cDNA libraries in a single step. The method is based on hybridization of the first-strand, full-length cDNA with several RNA drivers, including starting mRNA as the normalizing driver and run-off transcripts from minilibraries containing highly expressed genes, rearrayed clones, and previously sequenced cDNAs as subtracting drivers. Our method keeps the proportion of full-length cDNAs in the subtracted/normalized library high. Moreover, our method dramatically enhances the discovery of new genes as compared to results obtained by using standard, full-length cDNA libraries. This procedure can be extended to the preparation of full-length cDNA encyclopedias from other organisms.

Animals↗

PubMed2000

Observation of coherent cerenkov radiation from a solid dielectric with short bunches of electrons

Short bunches of 150-MeV electrons of a linear accelerator passed along the surface of a crystal quartz or a teflon and coherent Cerenkov radiation from the solid dielectrics has been observed in the wavelength range from 0.5 to 4 mm. Properties of the radiation have been experimentally investigated. The angular distribution of the observed radiation showed a maximum peak in the direction of the Cerenkov angle with several satellite peaks. The intensity increased linearly with increasing the length of the medium and was proportional to the square of the number of electrons in the bunch. The spectral intensity was enhanced by almost five orders of magnitude in comparison with the theoretical calculation of incoherent radiation.

Journal Article↗

PubMed2000

Mean corpuscular volume may be a useful index of risk for colorectal adenoma in middle-aged Japanese men.

OBJECTIVE: It has been reported that alcohol intake and folate deficiency are associated with an increased risk of colorectal adenomas and carcinomas. Mean corpuscular volume (MCV) of red blood cells has been reported to be increased in these conditions. The purpose of this study was to assess the association between MCV and risk of colorectal adenoma. METHODS: The subjects were 497 middle-aged (45-65 yr old) men who underwent both barium enema examination and total colonoscopy. The subjects answered a questionnaire regarding their alcohol consumption history, and their blood samples were analyzed. The subjects were divided into four groups three times: with or without alcoholism, and with or without adenoma according to alcohol intake, and according to the MCV value. Various variables were compared among the groups, and the odds ratios of adenoma were calculated. RESULTS: The MCV was higher in the alcoholic group than in the nonalcoholic group (p < 0.01) and in patients with adenoma than in those without adenoma (p < 0.0001). When the subjects were stratified by alcohol intake, the MCV value had a higher significant difference than alcohol intake, between patients with adenoma and those without adenoma. As for the MCV value, the odds ratio (95% confidence interval) of adenoma was 1.00 (referent); (<92), 1.20 (0.71-1.69); (> or =92 but <95), 2.61 (2.07-3.15); (> or =95 but <98); and 3.62 (2.99-4.25); (> or =98). CONCLUSION: A high MCV value may be used as a simple index of the risk of colorectal adenomas, regardless of alcohol consumption.

Adenoma↗

PubMed2000

Two distinct antigenic types of the polysaccharide chains of Helicobacter pylori lipopolysaccharides characterized by reactivity with sera from humans with natural infection.

We have purified lipopolysaccharides (LPS) from 10 Helicobacter pylori clinical isolates which were selected on the basis of chemotype and antigenic variation. Data from immunoblotting of the purified LPS with sera from humans with H. pylori infection and from absorption of the sera with LPS indicated the presence of two distinct epitopes, termed the highly antigenic and the weakly antigenic epitopes, on the polysaccharide chains. Among 68 H. pylori clinical isolates, all smooth strains possessed either epitope; the epitopes were each carried by about 50% of the smooth strains. Thus, H. pylori strains can be classified into three types on the basis of their antigenicity in humans: those with smooth LPS carrying the highly antigenic epitope, those with smooth LPS carrying the weakly antigenic epitope, and those with rough LPS. Sera from humans with H. pylori infection could be grouped into three categories: those containing immunoglobulin G (IgG) antibodies against the highly antigenic epitope, those containing IgG against the weakly antigenic epitope, and those containing both specific IgGs; these groups made up about 50%, less than 10%, and about 40%, respectively, of all infected sera tested. In other words, IgG against the highly antigenic epitope were detected in more than 90% of H. pylori-infected individuals with high titers. IgG against the weakly antigenic epitope were detected in about 50% of the sera tested; however, the antibody titers were low. The two human epitopes existed independently from the mimic structures of Lewis antigens, which are known to be an important epitope of H. pylori LPS. No significant relationship between the reactivities toward purified LPS of human sera and a panel of anti-Lewis antigen antibodies was found. Moreover, the reactivities of the anti-Lewis antigen antibodies, but not human sera, were sensitive to particular alpha-L-fucosidases. The human epitopes appeared to be located on O-polysaccharide chains containing endo-beta-galactosidase-sensitive galactose residues as the backbone. Data from chemical analyses indicated that all LPS commonly contained galactose, glucosamine, glucose, and fucose (except one rough strain) as probable polysaccharide components, together with typical components of inner core and lipid A. We were not able to distinguish between the differences of antigenicity in humans by on the basis of the chemical composition of the LPS.

Adult↗

PubMed2000

Loss of connexin45 causes a cushion defect in early cardiogenesis.

At around embryonic day 9, the primitive heart of a mouse embryo undergoes spectacular alterations within 24 hours. We created mice harboring an nls-lacZ gene in place of connexin45, which encodes the only known gap junction protein in the primitive heart before embryonic day 9, using the Cre-loxP system. Connexin45-deficient mice died of heart failure at around embryonic day 10. They initiated heart contractions, but conduction block appeared within 24 hours after the first contractions. Their cardiac walls displayed an endocardial cushion defect, while the cardiac jelly was present. These abnormalities were caused by impairment of the epithelial-mesenchymal transformation of the cardiac endothelium. Activation of the cardiac endothelium depended on the presence of the connexin45 gap junctions since signaling through Ca(2+)/calcineurin and NF-ATc1 (originally named NF-ATc) was disrupted in the mutant hearts. These results indicate a requirement for gap junction channels during early cardiogenesis and hence implicate connexin45 in congenital heart diseases. http://www. biologists.com/Development/movies/dev4369.html

Amino Acid Sequence↗

PubMed2000

Effects of a new steroidal aromatase inhibitor, TZA-2237, and/or chlormadinone acetate on hormone-induced and spontaneous canine benign prostatic hyperplasia.

OBJECTIVE: It has been known for many years that human benign prostatic hyperplasia (BPH) is composed predominantly of hyperplastic stromal cells rather than epithelial cells. In the present study the effects of a new steroidal aromatase inhibitor on hormone-induced and spontaneous canine BPH were investigated. METHODS: (1) Effects of TZA-2237 on hormone-induced canine BPH. Ten castrated beagles were administered testosterone and androstenedione 6 days/week for 8 months, and divided randomly into three groups after 2 months of treatment as follows. Group I served as controls, Group II was given 0.5 and Group III was given 2.5 mg/kg/day TZA-2237 5 days/week for 6 months. (2) Effects of TZA-2237 on spontaneous canine BPH. Twenty aged beagles with BPH were divided into five groups, Group IV was untreated, Group V was treated with 1 and Group VI with 5mg/kg/day TZA-2237 5 days/week for 31 weeks. Group VII was treated with 5mg/kg/day Atamestane and Group VIII was treated with 0.3 mg/kg/day chlormadinone acetate (CMA) 5 days/week. (3) Effects of TZA-2237 combined with CMA on spontaneous canine BPH. Three aged beagles with BPH were treated with 1mg/kg/day TZA-2237 and 0.03 mg/kg/day CMA 5 days/week for 20 weeks (Group IX) and a further three aged beagles with BPH were treated with 0.3 mg/kg/day CMA alone 5 days/week (Group X). RESULTS: Hormone-induced prostatic growth was significantly suppressed in group III compared with that in other groups. In Group III, the intraprostatic aromatase activity, estradiol level and androgen receptor content decreased significantly in comparison with the values in Group I. The prostatic weights in Groups V, VI and VII increased significantly in comparison with the weight in Group IV. Serum LH and testosterone levels in Groups V, VI, and VII increased significantly in comparison with the level in Group IV. The prostatic weight in Group IX was decreased only slightly, but the smooth muscle component was decreased significantly. CONCLUSIONS: TZA-2237 is a new, unique and effective aromatase inhibitor that causes inhibition of both epithelial and stromal compartments in hormone-induced canine BPH. Dual inhibition of androgen and estrogen resulted in inhibition of smooth muscle growth, and should prove effective as a new method of treatment given the atrophic effects on not only the epithelium but also the stroma in human BPH.

5-alpha Reductase Inhibitors↗

PubMed2000

Demographic and reproductive factors for high seroprevalence of Chlamydia trachomatis among pregnant women in Japan.

In order to elucidate demographic and reproductive factors associated with Chlamydia trachomatis seropositivity, serological screening and questionnaire survey were conducted on pregnant women in Nagasaki Prefecture, Japan. Serum samples were taken from 1718 pregnant women between September and December, 1996, at the cooperative obstetric hospitals and clinics, and tested for the presence of antibodies to C. trachomatis using the enzyme immunoassay. A questionnaire was administered on a sub-sample (n -409), among whom 85 (20.8%) were seropositive. A multiple logistic analysis revealed that four characteristics showed a significant association with the seropositivity: (i) experience of premarital pregnancy, (ii) non use of condoms, (iii) short duration of education, and (iv) more frequent induced abortion. The unsafe sexual behavior of young people lacking proper knowledge of how to prevent STD is the most important intervention target for control of the C. trachomatis epidemic in Japan.

Abortion, Induced↗