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Biomedical subjects

M Shimada

Publications and source records attributed to M Shimada.

At least 613 records · Page 34Linked to original sources
PubMed1992

[Aortic dissection associated with Turner's syndrome].

We report two cases of Turner's syndrome who had had coarctation repair and who ultimately died from complications believed to be associated with Turner's stigmata. Case 1. The repair of coarctation of the aorta (Co/Ao) at age 5 was associated with the tear of the aortic wall and an Asc. Ao-Desc. Ao bypass together with the closure of the Ao proximal to the Co/Ao was performed. At age 10, she developed a dissecting aneurysm of the Asc. Ao seemingly unrelated to the previous surgery and the Asc. Ao was replaced by a prosthetic tube graft. Pathological diagnosis was cystic medionecrosis. The aortic valve was bicuspid. Subsequently, the patient showed progressive worsening of the aortic regurgitation. The aortic valve replacement at age 14 was complicated by significant bleeding and the patient died on the fifth postoperative day. Case 2. Co/Ao was repaired at age 8. During the operation, the aortic wall appeared to be thin and friable, and there was some tear of the posterior suture line which necessitated reanastomosis with resultant stenosis. At age 9, stenotic area was enlarged by an onlay-patch of a piece of woven Dacron arterial graft. There was gradual swelling of that area on routine x-ray examinations and an aortography at age 16 showed definite aneurysm formation. At age 18, she suddenly developed hemoptysis. Rupture of the aneurysm into the pleural cavity and the left lung was suspected. An emergency surgery to stop bleeding under hypothermic cardiopulmonary bypass was unsuccessful and the patient died in OR.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Dissection↗
PubMed1991

The effect of apo E secretion on lipoprotein uptake in transfected cells.

To investigate the role of apolipoprotein E (apo E) secreted by peripheral tissues in local lipoprotein metabolism, we developed a cell strain that constitutively produced and secreted apo E. A fusion plasmid containing rat apo E genomic DNA under control of mouse metallothionein promotor was constructed and transfected into Chinese hamster ovary cells. A stable transformant designated CHO-MAEII constitutively secreted rat apo E mainly in the form of sialylated free protein. The secretion was further enhanced by metal induction up to 1 micrograms apo E/ml per 12 h. When incubated with 125I-labeled very low density lipoprotein (125I-VLDL) at 37 degrees C, CHO-MAEII took up and degraded 125I-VLDL with higher affinity than control cells. Furthermore, considerable amount of methylated 125I-VLDL was degraded by CHO-MAEII, while no methylated 125I-VLDL was degraded by control cells. No significant differences were found in the uptake of 125I-LDL. The data indicated that apo E molecules secreted by CHO-MAEII were transferred to 125-VLDL particles, which caused a higher affinity of these particles for LDL receptors on the cells. It is suggested that apo E secreted from peripheral tissues enhances the uptake of lipoproteins by themselves or by surrounding cells in the local environment which demand cholesterol and express LDL receptors. CHO-MAEII was a good model for these 'auto- or paracrine-like functions' of apo E.

Animals↗
PubMed1991

A random allocation system with the minimization method for multi-institutional clinical trials.

This paper describes the random allocation system used to perform precise and rapid treatment assignments in multi-institutional clinical trials. This system is based on sophisticated randomization procedures, according to Pocock and Simon's minimization method and Zelen's method for institution balancing. The major advantage of randomized treatment assignments with this system is to balance treatment numbers for each level of various prognostic factors over the entire trial and at the same time balance the allocation of treatments within an institution. Therefore, the randomized treatment assignments by this system can prevent degrading of the statistical power of a particular treatment factor. This system is designed to run on a small-sized notebook computer and therefore can be set up beside a telephone for registration, without occupying a large space. At present, this system is conveniently being used in two clinical trials.

Algorithms↗
PubMed1991

Free radical production by the red tide alga, Chattonella antiqua.

The red tide alga, Chattonella antiqua, was found to show a strong chemiluminescence, using luminol as the reagent, when exposed to ultraviolet irradiation. This luminescence was completely inhibited by ascorbate or catalase, suggesting that hydrogen peroxide was generated by the plankton. Red tide cells exposed to fish gill mucus from young yellowtail resulted in the release of a large number of mucocysts and a weak luminosity, and showed a strong reduction of cytochrome c in the medium. Therefore, the discharge of mucocysts from the red tide, induced by the presence of gill mucus, may be accompanied by the release of active oxygen species. The active oxygen may be involved in depolymerization of mucus glycoproteins from the gill lamellae.

Animals↗
PubMed1991

Ammonia elimination as a rapid index of viability in liver grafts in dogs.

We examined intraoperative changes in blood ammonia levels and the correlation with graft viability in orthotopic liver transplantation (OLTx) in 29 dogs. Blood ammonia levels following total hepatectomy were examined using five dogs. These levels immediately following hepatectomy (15 min) were significantly higher (212 +/- 29 micrograms/dl) over values noted before hepatectomy (93 +/- 11 micrograms/dl, P less than 0.05). OLTx was performed using the cuff technique. The animals were divided into two groups: Group A (n = 6 pairs), OLTx with a nonpreserved fresh graft; Group B (n = 6 pairs), OLTx with an 8-hr preserved graft with lactated Ringer (4 degrees C). In both groups, the blood ammonia levels before the surgery and at the anhepatic phase data did not differ; however, following reperfusion, the levels in Group B were significantly higher (211 +/- 26 at 15 min, 200 +/- 50 micrograms/dl at 30 min) than those in Group A (121 +/- 10 at 15 min; P less than 0.01, 109 +/- 9 micrograms/dl at 30 min; P less than 0.05). The blood ammonia level highly correlated with adenosine triphosphate contents in the liver tissue, blood level of lactic acid, and amount of bile output, all pertinent indicators of the graft viability. Thus, the potential to eliminate ammonia immediately after reperfusion can serve as an indicator of graft viability. The intraoperative monitoring of blood ammonia levels can be included in management guidelines in cases of liver transplantation.

Adenosine Triphosphate↗
PubMed1991

Simulation program for estimating statistical power of Cox's proportional hazards model assuming no specific distribution for the survival time.

Small sample properties of the maximum partial likelihood estimates for Cox's proportional hazards model depend on the sample size, the true values of regression coefficients, covariate structure, censoring pattern and possibly baseline hazard functions. Therefore, it would be difficult to construct a formula or table to calculate the exact power of a statistical test for the treatment effect in any specific clinical trial. The simulation program, written in SAS/IML, described in this paper uses Monte-Carlo methods to provide estimates of the exact power for Cox's proportional hazards model. For illustrative purposes, the program was applied to real data obtained from a clinical trial performed in Japan. Since the program does not assume any specific function for the baseline hazard, it is, in principle, applicable to any censored survival data as long as they follow Cox's proportional hazards model.

Clinical Trials as Topic↗
PubMed1991

A new single base substitution in a Japanese phenylketonuria (PKU) patient.

DNA analysis on phenylalanine hydroxylase (PAH) gene was performed in four Japanese PKU patients. By the Southern analysis, three patients were confirmed to be homozygous for haplotype 4, and the other one was homozygous for haplotype 2. Sequence analysis on the mutant PAH gene of this haplotype 2 patient, who was born to first-cousin parents, disclosed it to be a C-to-T transition in exon 7. This transition causes the substitution of Arg261 codon to a termination codon.

Base Sequence↗
PubMed1991

Formation of an ipsilateral corticospinal tract after ablation of cerebral cortex in neonatal rat.

The formation of an aberrant ipsilateral corticospinal tract after unilateral cerebral cortical ablation during the neonatal period has been confirmed in the rat. The tract was chronologically studied using the antegrade horseradish peroxidase (HRP) tracing method. An aberrant ipsilateral tract is not observed 3 days after the operation. However, ipsilateral HRP positive fibers become apparent on day 7 and progressively more prominent until day 14. These results suggest that the ipsilateral corticospinal tract is composed of collateral axons originating from pyramidal neurons in the healthy ipsilateral cerebral cortex. These results also indicate that, when cerebral cortex has the damage during early postnatal life, the remaining cortical neurons which have been freed from the damage show considerable plasticity in terms of the collateral axons.

Animals↗
PubMed1991

Congenital hydrocephalus in suckling hamsters caused by transplacental infection with parainfluenza virus type 3.

The possible occurrence of congenital hydrocephalus by viral infection of the mother was examined by inoculating pregnant hamsters intravenously with parainfluenza virus type 3 (PIV-3). We could produce congenital hydrocephalus in littermates born to a mother which had been inoculated into the left cervical vein on the 14th day of pregnancy. This result may indicate that the virus could pass through the placenta to arrive at the fetus, and infect the central nervous system.

Animals↗
PubMed1991

Simultaneous detection and typing of genital human papillomavirus DNA using the polymerase chain reaction.

A simple method has been developed for detecting a broad range of genital human papillomavirus (HPV) types using the polymerase chain reaction (PCR). We utilized two consensus sequence primer pairs within the E6 and E7 open reading frames to amplify HPV DNA; malignant HPV DNA (from HPV-16, -18, -31, -33, -52b and -58) was amplified using the pU-1M/pU-2R primer pair whereas benign HPV DNA (from HPV-6 and -11) was amplified using the pU-31B/pU-2R primer pair. Identification of the amplification product was confirmed by restriction enzyme digestion. In this study, a pU-1M/pU-2R-mediated PCR was successfully applied to 39 cervical carcinoma specimens; HPV-16 was detected in 19 cases, HPV-18 in five cases, HPV-31 in two cases, HPV-33 in two cases, HPV-52b in one case, HPV-58 in three cases, and an unknown type(s) was detected in four cases. Overall, the prevalence of HPV was 84.6%. The results indicate that this detection system is useful for the detection of HPVs not only of known types but also of new types.

Base Sequence↗
PubMed1991

Relatively low prevalence of human papillomavirus 16, 18 and 33 DNA in the normal cervices of Japanese women shown by polymerase chain reaction.

Ninety-two cervical scrapes and tissues, obtained from cytologically or histologically normal cervices of Japanese women, were examined for the presence of human papillomavirus (HPV) 16, 18 and 33 DNA by the polymerase chain reaction (PCR) method. Five out of 92 cases were HPV 16 DNA-positive, but neither HPV 18 nor 33 DNA was detected. The HPV (type 16, 18 and 33) prevalence rate in pregnant women, including postpartum, was 10% (3/31), which was higher than that in non-pregnant women. In two HPV 16-positive cases, we detected HPV 16 DNA again 2 months later. HPV (type 16, 18 and 33) prevalence in normal cervices was shown to be relatively low. However, it is very important to follow up the HPV-positive cases in cytologically normal cervices in order to elucidate the relation between HPV infection and the progression of cervical cancer.

Adolescent↗
PubMed1991

Neuronal differentiation of Ewing's sarcoma induced by cholera toxin B and bromodeoxyuridine--establishment of Ewing's sarcoma cell line and histochemical study.

An Ewing's sarcoma (ES) cell line was established from a metastatic bone marrow specimen in a patient with advanced disease, and some histochemical characteristics were investigated by neuronal differentiation induced with cholera toxin B (CTB) and bromodeoxyuridine (BrdU). Neuronal differentiation was investigated by the expression of neurofilament and Leu-7, and glial differentiation was observed by expression of S-100 protein. Neurofilament (NF) and Leu-7 were positive in ES cells and these were expressed more intensively by induction with CTB than with BrdU. There was no expression of S-100 protein in untreated or differentiated ES cells. ES cells became differentiated to neuronal cells with CTB and BrdU, but it was not observed, that ES cells had the potential to differentiate to glial cells. It appears that ES is of more primitive neural origin than neuroblastoma, primitive neuroectodermal tumors and other related neural tumors.

Antigens, Differentiation↗
PubMed1991

[A case of postpartum fever caused by Mycoplasma hominis infection].

A 26-year-old housewife was admitted to our hospital with a history of high fever after previous cesarean delivery. She had premature rupture of the membrane on the 41st week of pregnancy and the amniotic fluid was found to be cloudy on the fourth day after rupture. Therefore, cesarean delivery was performed. On the first day of operation, her body temperature increased up to 38 degrees C in spite of the treatment with Latamoxef (LMOX), 3 g/day. A sample of intrauterine material yielded M. hominis in pure culture. After administration of Minocycline (MINO) with antimycoplasmal activity, the clinical symptoms improved by the 11th day of operation. Sera obtained after the infection showed antibodies to M. hominis in ELISA study. These results suggested that the cause of this postpartum fever was M. hominis infection.

Adult↗
PubMed1991

Regulations of male-dominant P-450Md mRNA in rat liver by hormonal factors and xenobiotics.

Male-dominant P-450Md mRNA was undetectable in the livers of newborn rats. In female rat livers, the mRNA appeared at 17 days of age and then decreased to very low levels in the adult periods. The level of P-450Md mRNA in female rats was increased by phenobarbital or dexamethasone treatment, whereas the level in the males was depressed by methylcholanthrene. Hypophysectomy decreased the level of P-450Md mRNA in male rat livers, and continuous infusion or twice-daily injections of growth hormone to hypophysectomized rats caused further suppression or clear restoration, respectively, of the mRNA level.

Animals↗
PubMed1991

Improved method of porcine renal allografting for transplantation research.

This study presents a refined, reproducible, and clinically appropriate animal model of renal transplantation. A pair of kidneys are harvested from a donor pig and preserved in Euro-Collins' solution (4 degrees C). After a set period of preservation, the allografts are transplanted to two recipient pigs. The abdomen is entered through a midline incision. The right common iliac artery and vein are dissected and bilateral native nephrectomy is performed. Each allograft is then randomly assigned and transplanted to the recipients. Three minutes before unclamping, 100 mg of furosemide and 10 g of mannitol are given IV. Immediately after reperfusion, urine output is measured for 1 h. The allograft is biopsied and ureteroneocystostomy is created. Cystostomy is then placed using a 16F Foley catheter. The bladder neck is ligated to secure complete diversion of urine, and the abdomen is closed in layers. This kidney transplant model allows an absolutely paired study of the kidney allograft function from the same donor and also collection of pure urine at any time postoperatively, obviating the need for metabolic cages or sedation for urinary collection. This model and its unique modifications allow various transplant studies, including organ preservation, immunosuppressive protocol, and the prevention of reperfusion injury from oxygen free radicals.

Animals↗