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Biomedical subjects

Y Nishimura

Publications and source records attributed to Y Nishimura.

At least 307 records · Page 17Linked to original sources
PubMed1998

[Evaluation of the growth of a new pulmonary trunk after the reconstruction of right ventricular outflow tract without using an external conduit].

To evaluate the growth of a pulmonary trunk reconstructed without an extracardiac conduit, the hemodynamics and diameter of a new pulmonary trunk were measured in 5 patients from the right ventriculogram and MRI at postoperative follow-up periods. There were tetralogy of Fallot with pulmonary atresia in two patients, tetralogy of Fallot with single coronary in one, truncus arteriosus type I in one and transposition of the great arteries with ventricular septal defect and pulmonary stenosis in one. The age at operation ranged from 26 days to 4.5 years. The posterior wall continuity of the right ventricle and pulmonary artery was established by the direct pulmonary-right ventricular anastomosis in three patients and by the interposition of the left atrial appendage in two. Postoperative follow-up periods ranged from 2 years and 6 months to 3 years and 10 months (median: 2 years and 11 months). In four of them, the postoperative right ventricular to aortic or left ventricular systolic pressure ratios were less than 0.4 without any significant systolic pressure gradients between pulmonary artery and right ventricle. In these four patients, the diameters of the reconstructed pulmonary trunks grew from 10-18 mm to 18-21 mm postoperatively. These diameters were more than 100% of normal values. In the remaining patient with tetralogy of Fallot and single coronary artery, the obstruction of the new pulmonary trunk by a bulged left atrial appendage, which was used as the posterior wall, was observed on the right ventricular outflow tract reconstruction without an extracardiac conduit has growth potential in the future.

Bioprosthesis↗
PubMed1998

The angiotensin AT1 receptor antagonist CV-11974 regulates cerebral blood flow and brain angiotensin AT1 receptor expression.

We studied cerebral blood flow autoregulation by laser Doppler flowmetry, and expression of brain angiotensin II AT1 receptors by quantitative autoradiography, after administration of an angiotensin AT1 receptor antagonist, CV-11974 (Candesartan, 0.5 or 1.0 mg/kg.day) for two weeks via subcutaneously implanted osmotic pumps in adult normotensive Wistar Kyoto and spontaneously hypertensive male rats (SHR). In SHR, the autoregulation curve was shifted towards higher blood pressures, when compared with that of normotensive Wistar Kyoto rats. Administration of CV-11974 shifted the autoregulation curve toward lower blood pressures in both Wistar Kyoto and SHR, partially normalizing the autoregulation curve in SHR. CV-11974 treatment markedly decreased the expression of AT1 receptors in Wistar Kyoto rats, both in areas outside the blood brain barrier (subfornical organ, 95% decrease) and inside the blood brain barrier (nucleus of the tractus solitarius, 87% decrease, and paraventricular nucleus, 96% decrease). Our results demonstrate that blockade of AT1 receptors tends to normalize the shift to higher pressures in the autoregulation curve of genetically hypertensive rats, and has a profound modulatory role in brain angiotensin II AT1 receptors.

Angiotensin Receptor Antagonists↗
PubMed1998

Surgical treatment of a cardiac papillary fibroelastoma developing from the chordae of the tricuspid valve: report of a case.

Papillary fibroelastoma is a rare, benign cardiac tumor that can cause multiple emboli. We report herein a case of papillary fibroelastoma developing from the chordae of the tricuspid valve which was detected by echocardiography and confirmed by surgical resection. To our knowledge, this is only the fifth documented case of a tricuspid valve papillary fibroelastoma detected by echocardiography in a living patient.

Adult↗
PubMed1998

Cats are protected against feline immunodeficiency virus infection following vaccination with a homologous AP-1 binding site-deleted mutant.

Following establishment, via the vaginal route, of infection with an AP-1 binding-site deleted mutant (delta AP-1) of feline immunodeficiency virus (FIV), cats were challenged with a homologous intact strain (TM2) of FIV. The cats were observed for 23 weeks to evaluate the efficacy of the delta AP-1 against the homologous TM2 strain challenge. These two viruses were differentiated by Southern blotting after amplification of proviral DNA by semi-nested polymerase chain reaction in DNAs of peripheral blood mononuclear cells and tissues. A TM2-specific band was detected in one cat exposed to but not infected with delta AP-1, but not in two delta AP-1-infected. These results indicate that delta AP-1 could protect against subsequent challenge with homologous FIV TM2 strain.

Animals↗
PubMed1998

Clinicopathological and immunological characteristics of six cats with granular lymphocyte tumors.

Clinical and immunological characteristics were investigated in six cases of feline granular lymphocyte (GL) tumor. The ages of the affected cats were relatively old, ranging from 4 to 13 years of age. Gastrointestinal signs were commonly observed in these cases. Only one of the six GL tumor cases was positive for feline leukemia virus (FeLV) antigen. Phenotypic analysis revealed that the GL tumor cells from all of the six cases lacked the T- or B-cell markers. These GL tumor cells were examined by Southern blot analysis using feline immunoglobulin (Ig) and T-cell receptor (TCR) gene probes. GL tumor cells obtained from two cases were identified as cells of T-cell lineage by the presence of a rearranged TCR beta gene, whereas those from the other four cases were considered to be derived from non-T- non-B-cell lineage because of the absence of rearrangement of these genes. These findings indicated that feline GL tumors can be considered as a specific disease entity in feline lymphomas because the cases examined in this study showed onset at an older age, a low incidence of FeLV infection and frequent involvement of gastrointestinal lesions, which are not found in typical FeLV-associated lymphomas. Although no specific phenotypes was observed by phenotypic analysis, the feline GL tumor cells were divided into two consistent genotypes of T-cell or non-T- non-B-cell lineages.

Abdominal Neoplasms↗
PubMed1998

A new-born baby outbreak of echovirus type 33 infection.

OBJECTIVES: In 1994, an outbreak of echovirus type 33 (EV33) infection occurred in a maternity hospital in Japan. Nine new-born babies were infected, some presenting symptoms of encephalitis or disseminated intravascular coagulopathy. EV33 was isolated from the faeces or cerebrospinal fluid of all seven of the patients sampled, and serum antibody titres against EV33 were significantly elevated in the convalescence phase sera in all cases. SUBJECTS AND METHODS: To study what public health situations EV33 may become a serious pathogen for new born babies, serum EV33 antibody positivity in the general population was examined. Sera were obtained 649 samples before the outbreak, and 344 samples after the outbreak from aged 7 days to 65 years old. RESULTS: The average positive rate was 12.0% and the rate increased depending on age. Comparison of positive rates before and after this outbreak showed no increase in any age group. However, the positive rate was found to average only 5.6% in persons aged 16-30 years old, including pregnant women. This low positive rate in young adults would result in a lack or only a low level of antibodies in newborn babies. CONCLUSIONS: In conclusion, our findings suggest that EV33 infection in the new-born baby with no or low level of maternal neutralizing antibody may cause serious symptoms.

Adolescent↗
PubMed1998

Are hypoxic cells critical for the outcome of fractionated radiotherapy in a slow-growing mouse tumor?

PURPOSE: To investigate the significance of hypoxic cells, reoxygenation and repopulation for the outcome of fractionated radiotherapy of a slow-growing subline of a murine fibrosarcoma and to compare the results with those previously obtained from the original fast-growing tumor. MATERIALS AND METHODS: A slow-growing subline, 457-O, was obtained among the tumors that recurred after a single irradiation to the third generation isotransplants of a mouse fibrosarcoma, FSa-II. The single cell suspensions were transplanted into the mouse foot and when the tumors reached an average diameter of 4 mm, they were subjected to one to 20 equal daily y-ray doses given in air (A) or under hypoxic conditions (H). The TCD50 (50% tumor control radiation dose) was calculated according to the tumor control frequency within 180 days. The linear-quadratic plus time model was fitted to these data by logistic regression analysis. RESULTS: The volume doubling time of the 457-O tumors was approximately 2.2 times slower than that of the original FSa-II tumors. The TCD50(H) (single dose) was 52.3 Gy and increased with an increasing number of fractions to a TCD50(H) (20 doses) of 90.8 Gy. This increase of 38.5 Gy was much smaller than that of 149 Gy for the original FSa-II. The TCD50(A) (single dose) and TCD50(A) (20 doses) were 41.3 and 50.6 Gy, respectively. This small difference of 9.3 Gy contrasted with a significant increase of 52.9 Gy for the FSa-II. DISCUSSION: These results suggested no repopulation of 457-O tumor clonogens during the course of up to 20 daily doses, while the original FSa-II tumor cells repopulated substantially. Hypoxic clonogens in the slow-growing tumor reoxygenated but some fractions remained critical. CONCLUSION: The present data together with those obtained from the fast-growing FSa-II suggested that hypoxic clonogens were critical for the outcome of fractionated radiotherapy. Repopulation was insignificant in this slow-growing tumor during five to 20 daily doses.

Animals↗
PubMed1998

Genetic heterogeneity of env gene of feline immunodeficiency virus obtained from multiple districts in Japan.

Feline immunodeficiency virus (FIV) infection is widespread in many countries. FIV isolates have been classified into five distinct subtypes, A, B, C, D and E based on their env gene sequences. Several reports indicate that most of the FIVs isolated in Japan belong to subtype B which includes the first Japanese isolate, TM2 strain. To examine the distribution of FIV subtypes in Japan, proviral DNA sequences of the env gene were directly amplified by nested PCR from FIV-infected cats that had been kept in multiple districts throughout Japan. Phylogenetic analysis of the 11 strains showed that four FIV subtypes, A, B, C and D, were present in Japan. Among these subtypes, subtypes B and D were the two most common subtypes in Japan, and they were mainly distributed in the eastern and western parts of Japan, respectively. The present study provides information that is fundamental for development of a vaccine to protect against FIV infection in cats.

Amino Acid Sequence↗
PubMed1998

The biparental transmission of the mitochondrial genome in Chlamydomonas reinhardtii visualized in living cells.

In the isogamous green alga Chlamydomonas reinhardtii, the chloroplast genome is transmitted from the mt+ parent, while the mitochondrial genes are believed to be inherited from the mt- parent. Chloroplast nucleoids have been visualized by DAPI (4,6-diamidino-2-phenylindole) staining, and the preferential digestion of the mt- chloroplast nucleoids has been observed in young zygotes. However, the mitochondrial nucleoids have never been visualized, and their behavior is only deduced from genetic and biochemical studies. We discovered that the mitochondrial and chloroplast genomes can be visualized simultaneously in living cells, using the fluorescent dye SYBR Green I. The ability to visualize the mitochondrial and chloroplast genome in vivo permits the direct observation of the number, distribution and behavior of the chloroplast and mitochondrial nucleoids in young zygotes. Using this method, the biparental transmission of the mitochondrial genome was revealed.

Animals↗
PubMed1998

Thrombin-sensitive peptide linkers for biological signal-responsive drug release systems.

We have previously reported an elevation of thrombin-like activity in infected wound exudates. Therefore, using this enzymatic activity as a biological signal, a system which can release an antimicrobial drug at infected wounds was investigated. In this paper, we report thrombin-sensitive peptide linkers, the key component of this system. Starting from amino acid sequences of the cleavage site in fibrinogen, which is the substrate of thrombin, we synthesized some thrombin-sensitive peptide linkers. We constructed devices in which the thrombin-sensitive peptide linker interconnected between polyvinyl alcohol hydrogel and gentamicin. The device was able to release gentamicin in response to thrombin.

Gentamicins↗