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Biomedical subjects

Y Sawamura

Publications and source records attributed to Y Sawamura.

At least 19 recordsLinked to original sources
PubMed2006

Genetic mapping of the pear scab resistance gene Vnk of Japanese pear cultivar Kinchaku.

Pear scab (caused by Venturia nashicola) is one of the most harmful diseases of pears, especially Japanese and Chinese pear species. The molecular identification and early selection of resistant plants could greatly improve pear breeding. We have identified the position of the scab resistance gene, designated Vnk in an indigenous Japanese pear cultivar Kinchaku, within the pear genome by using simple sequence repeat (SSR) markers derived from pear and apple. The position of Vnk was identified in the central region of linkage group 1 of Kinchaku. Several amplified fragment length polymorphism (AFLP) markers linked to Vnk were obtained by bulked segregant analysis. Among them, the AFLP marker closest to Vnk was converted into a sequence tagged site (STS) marker. Four random amplified polymorphic DNA (RAPD) markers previously found to be loosely associated with Vnk (Iketani et al. 2001) were successfully converted into STS markers. Six markers (one SSR Hi02c07 and five STSs converted from AFLP and RAPD) showed tight linkages to Vnk, being mapped with distances ranging from 2.4 to 12.4 cM. The SSR CH-Vf2, which was isolated from a BAC clone of the contig containing the apple scab gene Vf, was mapped at the bottom of linkage group 1 in Kinchaku, suggesting that the Vnk and Vf loci are located in different genomic regions of the same homologous linkage group.

Ascomycota↗
PubMed2004

[Multi-vessel dissection; report of a case].

We report an extremely rare case of multi-vessel dissection including left carotid artery, ascending aorta and thoracoabdominal aorta independently. A 65-year-old man suffered from cerebral infarction due to left carotid artery dissection. Five days later, he complained of severe back pain and was diagnosed as acute DeBakey type IIIb aortic dissection. He had been treated medically. One month later, computed tomography (CT) scan demonstrated DeBakey type II as well as type IIIb aortic dissections. The ascending aorta was replaced on August 8, 2001. Then replacement of the descending thoracic aorta with reconstruction of the eighth and tenth intercostal arteries was performed on September 26, 2001. The left carotid artery dissection has been treated medically.

Aged↗
PubMed2003

MRI in methotrexate-related leukoencephalopathy: Disseminated necrotising leukoencephalopathy in comparison with mild leukoencephalopathy.

We report two fatal cases of methotrexate (MTX)-induced disseminated necrotising leukoencephalopathy (DNL) in which MRI was repeated from the onset. Initial T2-weighted images showed multiple areas of high signal, mainly in deep cerebral white matter, which on follow-up, spread and coalesced to involve the entire white matter. Small irregular low-signal foci on T2-weighted images were seen within the high-signal lesions. Multiple areas of contrast enhancement corresponded to these low-signal foci. The condition of both patients deteriorated and they died. We compared their MRI findings with those of seven patients with mild MTX-related leukoencephalopathy, six of whom were asymptomatic; one had transient neurological symptoms. They showed no contrast enhancement, but rather mild-to-moderate diffuse high signal in deep white matter, which later disappeared. These findings suggest that multiple low-signal foci on T2-weighted images with contrast enhancement may be characteristic of DNL, and that contrast-enhanced imaging is useful to differentiate this condition from mild leukoencephalopathy.

Adolescent↗
PubMed2003

Clinical study of urine NMP 22 (nuclear matrix protein 22) as a tumor marker in urinary epithelial cancer.

The prognosis of urinary epithelial cancer is still poor, and early detection of this cancer is strongly desirable. The sensitivity of conventional urinary cytology is not satisfactory enough. It is hoped that a specific tumor marker will be established. In recent years, it has been reported that urine NMP 22 is very useful and that urine BFP is also relatively useful. We have now determined urine NMP22 and BFP and studied their clinical usefulness as a tumor marker. Using patients diagnosed with histologically confirmed urinary epithelial cancer as the subjects, we retrospectively studied the usefulness of NMP 22, BFP and cytology mainly with regard to the sensitivity (positivity rate), and also in relation to atypia, degree of infiltration and clinical course.

Biomarkers, Tumor↗
PubMed2002

Genetic linkage maps constructed by using an interspecific cross between Japanese and European pears.

Genetic linkage maps of the European pear ( Pyrus communis L.) cultivar 'Bartlett' and the Japanese pear ( Pyrus pyrifolia Nakai) cultivar 'Housui' were constructed based on AFLPs, SSRs from pear, apple and Prunus, isozymes and phenotypic traits by using their F(1) progenies. The map of the female parent Bartlett consisted of 226 loci including 175 AFLPs, 49 SSRs, one isozyme and one S locus on 18 linkage groups over a total length of 949 cM, while that for 'Housui' contained 154 loci including 106 AFLPs, 42 SSRs, two phenotypic traits and the other four markers on 17 linkage groups encompassing a genetic distance of 926 cM. These maps were partially aligned using 20 codominant markers which showed segregating alleles in both parents. Compared with the reports of apple genetic maps, these pear maps were not saturated but were near saturation. Distorted segregation was observed in two and one regions of the genome of Bartlett and Housui, respectively. The position of 14 SSRs originating from apple could be successfully determined in pear maps, which enabled us to compare the two maps. Some SSRs developed from Prunus (peach, cherry) were also mapped. The relationships between pear and the other species belonging to the Rosaceae were discussed based on the position of SSRs.

Chromosome Mapping↗
PubMed2002

[Pericardiectomy for post-coronary artery bypass grafting constrictive pericarditis; strategy for safe and complete pericardiectomy].

Surgery for constrictive pericarditis after coronary artery bypass grafting (CABG) needs complete pericardiectomy without injury to bypass grafts. We performed pericardiectomy for post-CABG constrictive pericarditis 15 months after the first surgery. Preoperative multislice helical 3-dimensional computed tomography (CT) clearly demonstrated the patent bypass grafts and anatomical relationship between grafts and surrounding organs. Among surgical approaches, we chose bilateral thoracotomy to avoid injury to the bypass grafts and to obtain a good surgical exposure, especially for pericardiectomy of the left side of the heart. Additionally, with the use of intraoperative doppler ultrasound blood flowmetry, we could safely achieve complete pericardiectomy. We conclude that the combined application of 3-dimensional CT, bilateral thoracotomy and doppler ultrasound blood flowmetry was a supreme strategy for the operation of constrictive pericarditis after CABG.

Coronary Artery Bypass↗
PubMed2001

Restoration of endogenous wild-type p53 activity in a glioblastoma cell line with intrinsic temperature-sensitive p53 induces growth arrest but not apoptosis.

p53 protein is a transcription factor involved in multiple tumor-suppressor activities including cell cycle control and apoptosis. TP53 gene is frequently mutated in glioblastoma, suggesting the importance of inactivation of this gene product in gliomagenesis. Restoration of p53 function in glioblastoma cell lines deficient for p53 has shown that p53 induces growth arrest or apoptosis depending on the cell line and vector used to transduce wild-type TP53 alleles. Considering that astrocytes grow and express p53, it is not clear whether these results reflect physiologic responses or the result of p53 overexpression in combination with cellular responses to viral vector infection. Here, we reassessed this issue using a glioblastoma cell line (LN382) that expresses an endogenous temperature-sensitive mutant p53. This cell line expresses TP53 alleles (100% as determined by a p53 transcriptional assay in yeast) mutated at codon 197 GTG (Val) > CTG (Leu). We found that the p53 protein in these cells acted as an inactive mutant at 37 degrees C and as a functional wild-type p53 below 34 degrees C as demonstrated by several lines of evidence, including (i) restoration of transactivating ability in yeast, (ii) induction of p53-modulated genes such as CDKN1(p21) and transforming growth factor-alpha, (iii) disappearance of accumulated p53 protein in the nucleus and (iv) decrease in steady state p53 protein levels. This temperature switch allowed p53 levels, which were close to physiological levels to dramatically reduce LN382 cell proliferation by inducing a G(1)/S cell cycle block, but not to induce apoptosis. The lack of apoptosis was considered to be a result of the low level p53 expression, because increasing wild-type p53 levels by adenoviral-mediated gene transfer caused apoptosis in these cells. The LN382 cell line will be extremely useful for investigations into the roles of p53 in cellular responses to a variety of stimuli or damages.

Apoptosis↗
PubMed2001

A novel single nucleotide polymorphism altering stability and activity of CYP2a6.

CYP2A6 is known as a major cytochrome P450 (CYP) responsible for the oxidation of nicotine and coumarin in humans. In this study, we explored genetic polymorphisms, which reduce CYP2A6 activity in Japanese. Two novel mutations in exon 9 of the CYP2A6 gene were found. A single nucleotide polymorphism of T1412C and G1454T resulted in Ile471Thr and Arg485Leu substitution, respectively. The frequency of the former variant allele was considerably high (15.7%), while the latter variant appeared to be a rare polymorphism. Heterologous expression of CYP2A6 using a cDNA possessing C instead of T-base at codon 471 in Escherichia coli caused remarkable reduction of the stability of holoenzyme at 37 degrees C. Furthermore, this variant enzyme almost lacked nicotine C-oxidase activity, although coumarin 7-hydroxylase activity was still observed. These data suggest that individuals homozygous for the T1412C variant allele or heterozygous for this and a defect allele such as the CYP2A6*4 may be poor metabolizer of nicotine, but not coumarin.

Aryl Hydrocarbon Hydroxylases↗
PubMed2001

Alternative EWS-FLI1 fusion gene and MIC2 expression in peripheral and central primitive neuroectodermal tumors.

Primitive neuroectodermal tumors (PNET) occur either in the central nervous system (CNS; central PNET, cPNET) or in the peripheral sites (peripheral PNET, pPNET). Recent molecular approaches have been defining a new concept of PNET, that is, the pPNET including Ewing's sarcoma (ES) which expresses MIC2 glycoprotein and shows the specific chimeric gene of EWS-FLI1. The expression of MIC2 and the genetic rearrangement of EWS-FLI1 are considered to be highly specific to the pPNET/ES. This study examined the expression of MIC2 and EWS-FLI1 gene by means of immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR) on various small round cell tumors originating in the CNS or non-CNS organs. All peripheral PNET tested expressed MIC2 and were positive for EWS-FLI1 (11/11). In contrast, all cPNET and other blastic CNS tumors were negative for MIC2: medulloblastoma (0/3), cerebral PNET (0/2), spinal PNET (0/2), glioblastoma (0/2), retinoblastoma (0/3), and pineoblastoma (0/2). These MIC2-negative tumors were also negative for the chimeric gene product of EWS-FLI1. Interestingly, one PNET originating in the intracranial dura mater was positive for both MIC2 and EWS-FLI1 fusion gene. The results indicate that cPNET lacks any genetic or protein markers, except for a meningeal PNET which falls into the same phenotypic spectrum of pPNET.

12E7 Antigen↗
PubMed2001

JC virus large T protein transforms rodent cells but is not involved in human medulloblastoma.

JC virus (JCV) together with Simian virus 40 (SV40) and BK virus (BKV), belong to the polyomavirus group and these viruses are neuro-oncogenic to rodents by expression of large T antigen (LT), which binds to cellular p53 and pRB thus reducing the anticancer potential of the cell. The function of LT has not been clarified because small t antigen (st) is transcribed from the same start codon as the overlapping reading frame of LT, and is translated as a different protein with the same N-terminal residues (1-81 amino acids) by a splice-site variant of mRNA. To elucidate the function of LT without st, we constructed plasmids that express LT only by deleting the splicing region including the C-terminus of st, and consequently stable cell lines were established that express only JCLT, SV40LT and BKLT. The growth rates of these cells were examined in colonies on soft agar and it was found that LT alone has a transforming capacity; the order of efficiency being SV40LT, BKLT and JCLT. In addition, to verify the involvement of JCV in human medulloblastoma, eight cases of medulloblastoma, six cases of frozen material and five cases of paraffin-embedded tissues which included three cases of frozen tissues, were examined. PCR assay, genomic Southern blotting, and in situ hybridization were applied to detect the JCV genome, and LT and st were examined by immunohistochemistry; the results were compared with JCV-infected tissues as a positive control. All methods failed to detect not only JCV genome but also LT protein in medulloblastoma and it was concluded that JCV LT has transforming activities in rodent cells, but is not related to human medulloblastoma.

3T3 Cells↗
PubMed2001

Penile schwannoma.

Schwannoma of the penis is extremely rare. A 65-year-old man presented with a subcutaneous tumor of penile shaft without any other symptoms. Histopathologic examination of the excised tumor revealed benign schwannoma. No recurrence has been observed over the 6 months since the surgery.

Aged↗
PubMed2001

A clinical study of urine basic fetoprotein and urine polyamine as tumor markers in epithelial cancer of the urinary tract.

BACKGROUND: The reliability of a new screening test for epithelial cancer of the urinary tract was evaluated and the results were compared with those obtained employing urinary cytology in routine use. METHODS: The subjects consisted of 187 cases selected randomly from among the patients who attended Toho University Ohashi Hospital during a period of 1 year from January 1998. The values for urine basic fetoprotein (BFP) and polyamine and urinary cytology were examined. RESULTS: Urine BFP is considered useful for screening and monitoring urinary tract epithelial cancer as is urinary cytology. Urine BFP showed a statistically significant difference (P < 0.05) for G1 compared with urinary cytology and a significantly high level compared with urinary cytology as to the positive rate in the low stage group (P < 0.05). The positive rate of urine BFP was high in patients with urinary tract infection. CONCLUSION: Determining urine BFP, when combined with urinary cytology, is considered very useful for diagnosing patients with urinary tract epithelial cancer. This study suggests the possibility of urine BFP being superior to urinary cytology for screening early cancer and also as an indicator for observations on the clinical course.

Adolescent↗
PubMed2001

Ultrafiltration of the priming blood before cardiopulmonary bypass attenuates inflammatory response and improves postoperative clinical course in pediatric patients.

The priming solution using in cardiopulmonary bypass (CPB) for infants undergoing cardiac surgery includes considerable amounts of stored blood. Our objective was to test the hypothesis that ultrafiltration (UF) of the stored blood before CPB reduces the unfavorable effects of stored blood and the production of inflammatory cytokines. Fifty pediatric patients with congenital heart defects took part in this study. The patients were randomly divided into two groups: the UF (27 pediatric patients who received UF) and control (23 pediatric patients who did not receive UF) groups. UF was performed with a polysulphone ultrafiltrator before CPB. Blood samples were collected immediately before, during, and 1 h after CPB. The levels of cytokines (TNF-alpha, IL-1beta, IL-8), NH3, and bradykinin were determined. The serum concentrations of NH3 and bradykinin decreased significantly after UF. Compared with the control group, the UF group had significantly lower cytokine production. Water balance in UF group was better than that of control group. The UF group received significantly less inotropic support and shorter duration of ventilator support and ICU stay. We conclude that removal of bradykinin and a decrease in the levels of NH3, potassium, and pH play a significant role in reducing water retention and postoperative lung injury. UF of the blood used to prime the circuit for CPB is a safe and efficient method for use in open heart surgery in small pediatric patients.

Ammonia↗