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N Shimizu

Publications and source records attributed to N Shimizu.

At least 361 records · Page 20Linked to original sources
PubMed1998

Genomic organization of the human myocilin gene (MYOC) responsible for primary open angle glaucoma (GLC1A).

Myocilin is a newly found cytoskeletal protein involved in the morphogenesis of the basal body, a major microtubule organizing center, of the ciliated epithelium. It was recently realized that myocilin is virtually identical to the independently reported protein TIGR (trabecular meshwork-induced glucocorticoid response), which is responsible for the pathogenesis of chromosome 1q-linked primary open angle glaucoma (GLC1A). In this paper, we determined the genomic organization of the myocilin (MYOC/TIGR) gene by analyzing the nucleotide sequence of the BAC clones containing the MYOC/TIGR gene. The MYOC/TIGR gene consists of three exons. Each of the two splice donor and acceptor sites agrees well with the GT/AG rule. Primer sets to amplify each of the three exons are designed. The 5'-flanking region of MYOC gene contains the TGTTCT sequence overlapped with a palindromic sequence TTCTTTTTAAAAAGAA, which appears to be a glucocorticoid responsive element. There is also a unique sequence of dinucleotide repeat [(GT)2AA(GT)4AC(GT)13] which may also serve as a regulatory element. These results should aid in further detection of the MYOC/TIGR gene mutation and in depth understanding of the tissue-specific MYOC gene regulation.

Amino Acid Sequence↗
PubMed1998

Molecular genetic analysis of a novel Parkin gene in Japanese families with autosomal recessive juvenile parkinsonism: evidence for variable homozygous deletions in the Parkin gene in affected individuals.

Autosomal recessive juvenile parkinsonism (AR-JP) is a distinct clinical and genetic entity characterized by selective degeneration of nigral dopaminergic neurons and young-onset parkinsonism with remarkable response to levodopa. Recently, we mapped the gene locus for AR-JP to chromosome 6q25.2-q27 by linkage analysis and we identified a novel large gene, Parkin, consisting of 12 exons from this region; mutations of this gene were found to be the cause of AR-JP in two families. Now we report results of extensive molecular analysis on 34 affected individuals from 18 unrelated families with AR-JP. We found four different homozygous intragenic deletional mutations, involving exons 3 to 4, exon 3, exon 4, and exon 5 in 10 families (17 affected individuals). In addition to the exonic deletions, we identified a novel one-base deletion involving exon 5 in two families (2 affected individuals). All mutations so far found were deletional types in which large exonic deletion accounted for 50% (17 of 34) and the one-base deletion accounted for 6% (2/34); in the remaining, no homozygous mutations were found in the coding regions. Our findings indicate that loss of function of the Parkin protein results in the clinical phenotype of AR-JP and that subregions between introns 2 and 5 of the Parkin gene are mutational hot spots.

Amino Acid Sequence↗
PubMed1998

Effects of inhaled nitric oxide in canine lung transplantation from non-heart-beating donor.

Nitric oxide (NO) is believed to be identical to endothelium-dependent-relaxing-factor, a potent vasodilator. In addition, NO has been founded to play a critical role in the maintenance of vascular permeability through its attenuation of polymorphonuclear neutrophils (PMN) and platelets. In the present study, we have evaluated the effects of inhaled NO at reperfusion in canine left single-lung allotransplantation from a non-heart-beating donor. Twelve weight-matched pairs of adult mongrel dogs were used. The donor dogs were sacrificed by an intravenous injection of potassium chloride without heparinization. They were left at room temperature for 3 hours. Then, the recipient dogs received a left single-lung allotransplantation. After implantation, the right bronchus and pulmonary artery were ligated. In Group 1 (n = 6), NO gas was administered continuously at a concentration of 40 parts per million throughout a 6-hour assessment period. In Group 2 (n = 6), nitrogen gas was administered in the same manner as NO, for control. The survival time in Group 1 was significantly longer than that in Group 2. The arterial oxygen tension in Group 1 was significantly higher than that in Group 2. The pulmonary vascular resistance was significantly lower in Group 1 than in Group 2. The aortic pressure and the cardiac output each did not differ significantly between the two groups. Myeloperoxidase activity was significantly lower in Group 1 than in Group 2. Inhaled NO at reperfusion is beneficial in lung transplantation from non-heart-beating donors because it attenuates ischemia-reperfusion injury by inhibiting PMN activation and vasodilating pulmonary vasculature.

Administration, Inhalation↗
PubMed1998

Hypersusceptibility to DMCM-induced seizures during diazepam withdrawal in mice: evidence for upregulation of NMDA receptors.

The present study investigated the role of NMDA (N-methyl-D-aspartate) receptors in the hypersusceptibility to seizures induced by the benzodiazepine inverse agonist DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate) during diazepam withdrawal in mice, using behavioral and biochemical approaches. The seizure threshold of DMCM was markedly decreased during diazepam withdrawal, reflecting withdrawal hyperexcitability in response to physical dependence. The decrease in the seizure threshold of DMCM in diazepam-withdrawn mice was inhibited by the non-competitive NMDA receptor antagonists MK-801 ((+)-5-methyl-10,11-dihydro-5H-dibenzo(a,d)cycloheptan-5,10-imine maleate; 50 microg/kg, s.c.) and ifenprodil (20 mg/kg, i.p.). The effective doses of these compounds were lower than those required to prevent DMCM-induced seizures in chronically vehicle-treated mice. Since MK-801 and ifenprodil do not only bind to NMDA receptors but also to sigma receptors, the present study also investigated the effects of sigma receptor ligands. The decrease in the seizure threshold of DMCM in diazepam-withdrawn mice was not modified by the sigma receptor agonist, (+)-pentazocine (5 mg/kg, s.c.), or the sigma receptor antagonist, NE-100 (N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride; 5 mg/kg, i.p.). Furthermore, the latency to the expression of wild running induced by intracerebroventricular administration of NMDA (60 ng/mouse) was also significantly lower in diazepam-withdrawn mice than in vehicle-treated control mice. On the other hand, there was no difference in the spermidine concentration between vehicle-treated control and diazepam-withdrawn mice. In a receptor binding experiment, the Bmax value for [3H]-MK-801 binding was significantly increased in cerebrocortical tissues from diazepam-withdrawn mice, while the Kd value did not change in either group. However, the acute addition of a high concentration of diazepam (10 and 100 microM) in vitro did not alter [3H]-MK-801 binding in cerebrocortical membrane preparations. The behavioral experiments suggest that NMDA receptor antagonists may suppress benzodiazepine withdrawal responses, while the biochemical study reveals upregulation of the NMDA receptor, which may play an important role in the hypersusceptibility to DMCM-induced seizure in diazepam-withdrawn mice.

Animals↗
PubMed1998

Molecular and clinical study of 183 patients with conotruncal anomaly face syndrome.

To investigate molecular and clinical aspects of conotruncal anomaly face (CAF), we studied the correlation between deletion size and phenotype and the mode of inheritance in 183 conotruncal anomaly face syndrome (CAFS) patients. Hemizygosity for a region of 22ql1.2 was found in 180 (98%) of the patients with CAFS by fluorescence in situ hybridization (FISH) using the N25(D22S75) DiGeorge critical region (DGCR) probe. No hemizygosity was found in three (2%) of the patients with CAFS by FISH using nine DiGeorge critical region probes and a SD1OP1 probe (DGA II locus). None of these three patients had mental retardation and just one had nasal intonation, which was observed in almost all of the 180 CAFS patients who carried deletions (mental retardation, 92%; nasal voice, 88%). Nineteen of 143 families (13%) had familial CAFS and 16 affected parents (84%) were mothers. Although only two of the affected parents had cardiovascular anomalies, the deletion size in the 16 affected parents and their affected family members, who were studied by FISH analysis, was the same. It indicates that extragenic factors may play a role in the genesis of phenotypic variability, especially in patients with cardiovascular anomalies. No familial cases were found among CAFS patients with absent thymus/DiGeorge anomaly (DGA). Also, in all 18 CAFS patients with completely absent thymus/DGA and all 6 CAFS patients with schizophrenia, it was revealed that the deletion was longer distally. A study of the origin of the deletion using microsatellite analyses in 48 de novo patients showed that in 65% of CAFS patients it was maternal, while in 64% of DGA patients it was paternal. The findings of this study indicated that CAF was almost always associated with the deletion of 22ql1.2. As well as the major features of the syndrome, other notable extracardiac anomalies were found to be susceptibility to infection, schizophrenia, atrophy or dysmorphism of the brain, thrombocytopenia, short stature, facial palsy, anal atresia, and mild limb abnormalities.

Adolescent↗
PubMed1998

Identification and characterization of a novel cyclic nucleotide phosphodiesterase gene (PDE9A) that maps to 21q22.3: alternative splicing of mRNA transcripts, genomic structure and sequence.

Cyclic nucleotide-specific phosphodiesterases (PDEs) play an essential role in signal transduction by regulating the intracellular concentration of second messengers (cAMP and cGMP). We have identified and made an initial characterization of a full-length cDNA encoding a novel human cyclic nucleotide phosphodiesterase, PDE9A. At least four different mRNA transcripts (PDE9A1, A2, A3, A4) are produced as a result of alternative splicing of 5' exons, potentially changing the N-terminal amino acid sequences of the encoded proteins. All these predicted proteins would contain a 3',5'-cyclic nucleotide phosphodiesterase signature motif (Prosite no. PDOC00116). Northern blot analysis revealed several mRNA species of approximately 2.4 kb with varying expression patterns and intensities in most tissues examined, except blood. We have also isolated the mouse homolog of the human PDE9A2 mRNA transcript, pde9A2. The human and mouse isoforms have 93 and 83% sequence identity at the amino acid and nucleotide levels, respectively. PDE9A was mapped to 21q22.3, between TFF1 and D21S360. Comparison of the PDE9A1 cDNA with the genomic sequence from the region revealed that the gene is split into 20 exons that extend over 122 kb. Comparison of the physical map of the region and the genomic sequence further refines the mapping, with D21S113 being derived from intron 15. Several genetic disorders map to 21q22.3, including one form of bipolar affective disorder. Since functional disturbances in intraneuronal signal transmission via second messengers play an important role in the pathophysiology of affective disorders, PDE9A is a strong candidate for such a role by position and function.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

A common mutation in Sardinian autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy patients.

Autoimmune polyendocrinopathy-candidiasisectodermal dystrophy (APECED; also called APS-1,) is a rare autosomal recessive disorder that is more frequent in certain isolated populations. It is characterized by two of the three major clinical symptoms that may be present: Addison's disease, and/or hypoparathyroidism and/or chronic mucocutaneous candidiasis. We have recently identified the gene for APECED, which we termed AIRE (for autoimmune regulator). AIRE is expressed in thymus, lymph nodes and fetal liver, and encodes a protein with two putative zinc fingers and other motifs suggestive of a transcriptional regulator. Seven mutations have been described to date, including R257X, the predominant Finnish and northern Italian APECED allele, which has also been observed in other patients of diverse origin on different haplotypes. A 13-bp deletion (1094-1106del) has also been observed in several patients of different geo-ethnic origin. The other described mutations appear to be rare. We present mutational analyses of the AIRE gene in ten Sardinian APECED families and show that there is a mutation, R139X, associated with one predominant haplotype unique to the Sardinian patients (18/20 independent alleles). The carrier frequency of R139X in Sardinia is 1.7%, giving an estimated population frequency of APECED of 1/14,400. Using linkage disequilibrium data, the estimated age of the R139X mutation is between 20 and 25 generations. A previously described 13-bp deletion was also observed on an allele of one patient. The identification of a single common Sardinian APECED mutation will facilitate its genetic diagnosis. Given the carrier frequency of R139X in the Sardinian population, AIRE may be implicated in the pathogenesis of other autoimmune diseases in the Sardinian population, particularly those affecting the endocrine system.

DNA Mutational Analysis↗
PubMed1998

The suppression of postoperative liver metastasis caused by the continuous intraportal infusion of angiogenesis inhibitor FR-118487 in a rabbit colon cancer model.

The inhibitory effect of FR-118487, a potent angiogenesis inhibitor, on neovascularization induced by the VX2 tumor was confirmed in a rabbit corneal assay. The antimetastatic effect of FR-118487 was also investigated in 21 rabbits. Spontaneous liver metastases were induced by VX2 tumor cell implantation into the ascending colonic wall. FR-118487 was then infused continuously into the portal vein for 7 days after resection of the primary lesion at a dose of 1 mg/kg/day (FR-1 group) or 3 mg/kg/day (FR-3 group). The incidence of liver metastases was 71.4%, occurring in 5 of 7 rabbits, in each of the FR-1 and FR-3 groups, compared with 100%, being all of 7 rabbits, in the control group. The number of metastatic foci tended to be less in the FR-1 (31.0 +/- 36.0) and FR-3 (24.6 +/- 45.1) groups than in the control group (83.7 +/- 73.9) and the weight of metastatic foci was significantly less in the FR-1 (1.4 +/- 1.8 g) and FR-3 (1.3 +/- 2.0 g) groups than in the control group (6.5 +/- 4.9 g) (P < 0.05). However, leakage of the colonic anastomosis and body weight loss were limited to the FR-3 group. These results suggest that the continuous intraportal infusion of FR-118487 at 1 mg/kg/day suppressed liver metastases by inhibiting angiogenesis, without producing any adverse effects.

Animals↗
PubMed1998

Beneficial effects of prostaglandin E1 on ischemic colitis following surgery on the abdominal aorta.

To determine the effects of prostaglandin E1 (PGE1) on the intestinal circulation, an experimental dog model of ischemic colitis following abdominal aortic reconstruction was made by ligating the inferior mesenteric artery (IMA) and the internal iliac artery, with the creation of a 50% stenosis in the superior mesenteric artery (SMA). The parameters of enteric ischemia included the blood flow of the SMA, the tissue blood flow in the small intestine and left colon, the mean stump pressure of the IMA (IMAP), and the IMAP/mean systemic blood pressure ratio. With the continuous infusion of 10 ng/kg per minute of PGE1 into the descending thoracic aorta, these values increased significantly on the seventh postoperative day compared with those on the day of operation. These results thus suggest that the continuous intraarterial infusion of PGE1 may reduce ischemic changes in the colon following abdominal aortic reconstruction.

Alprostadil↗
PubMed1998

The classic form of granular corneal dystrophy associated with R555W mutation in the BIGH3 gene is rare in Japanese patients.

PURPOSE: To identify the BIGH3 gene mutation in 10 unrelated Japanese individuals with granular corneal dystrophy. METHODS: Genomic DNA was obtained from each patient's leukocytes. Exons 4 and 12 of the BIGH3 gene were amplified by polymerase chain reaction and were directly sequenced. RESULTS: Nine of these patients were found to have the R124H mutation, whereas only one had the R555W mutation. Slit-lamp examination showed that the granular corneal dystrophy associated with each mutation is different. CONCLUSIONS: These results, together with our previous findings, show that the classic form of granular corneal dystrophy associated with the R555W mutation is rare in Japanese patients, whereas granular corneal dystrophy accompanied by amyloid deposits and associated with the R124H mutation, Avellino corneal dystrophy, is more common. Direct examination may be insufficient in the proper diagnosis of corneal dystrophy, and BIGH3 mutation analysis may be required.

Adult↗
PubMed1998

Thoracoscopic operation for secondary pneumothorax under local and epidural anesthesia in high-risk patients.

BACKGROUND: Video-assisted thoracic operations usually require single-lung ventilation under general anesthesia. However, for high-risk patients with other underlying pulmonary diseases, one has to consider risks of general anesthesia itself. METHODS: Four high-risk patients (4 men; mean age, 73 years) with intractable secondary pneumothorax and other underlying pulmonary diseases were treated by video-assisted thoracic operations under local and epidural anesthesia. Absorbable polyglycolic acid sheets and fibrin glue were used to control the air leakage. RESULTS: The mean duration of the procedure was 108 minutes. Pain and cough reflex were well controlled, and spontaneous breathing and hemodynamics were well maintained during the operation. The mean duration of the postoperative chest drainage was 5 days. No significant postoperative complication was encountered. No pneumothorax had recurred at a mean follow-up of 16 months. CONCLUSIONS: Video-assisted thoracic operations can be performed safely under local and epidural anesthesia for the treatment of intractable secondary pneumothorax in high-risk patients. The air leakage can be controlled with the use of polyglycolic acid sheets and fibrin glue without bullectomy.

Aged↗
PubMed1998

Bilateral lung volume reduction surgery via median sternotomy for severe pulmonary emphysema.

BACKGROUND: Lung volume reduction surgery either via sternotomy or by thoracoscopy has been demonstrated to be effective for selected emphysema patients in North America and Europe. The present study summarizes short-term results of bilateral lung volume reduction performed via median sternotomy for the first consecutive 39 patients with severe diffuse emphysema in Okayama, Japan, from July 1995 to February 1997. METHODS: There were 35 men and 4 women, and the age range was 54 to 74 years with a mean age of 65 years. All were former heavy smokers and none of them had alpha1-antitrypsin deficiency. Only 9 patients (23%) showed a bilateral upper lobe pattern of emphysema. The operation was done through a median sternotomy, and the most emphysematous portions were excised bilaterally with a linear stapling device fitted with strips of bovine pericardium to prevent air leakage. RESULTS: No operative death was encountered. The first 33 patients completed 3-month follow-up assessment, and their mean forced expiratory volume in 1 second had improved by 41% from 735 mL to 1,037 mL. Other parameters of pulmonary function tests, arterial blood gas analysis, 6-minute walking distance, and dyspnea scale also had improved significantly. These improvements lasted for at least a year. CONCLUSIONS: Bilateral lung volume reduction surgery via median sternotomy is a safe and effective procedure for selected severe emphysema patients. Although the pattern of emphysema might be different between countries, the results in Japanese patients were similar to those previously reported in North American and European patients.

Aged↗
PubMed1998

Origin of regenerated epithelium in cryopreserved tracheal allotransplantation.

BACKGROUND: Our previous study showed that a cryopreserved tracheal allograft could be transplanted using omentopexy without immunosuppression. The present study investigated, by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method, whether the regenerated epithelia were of recipient origin or donor origin in a cryopreserved tracheal allotransplantation model. METHODS: Twenty-nine mongrel dogs were classified by preoperative peripheral blood PCR-RFLP analysis. The cryopreserved tracheal allografts were implanted into recipient animals that showed a different phenotype from donor animals. A small specimen of epithelia excised from the allograft of animals postmortem was analyzed with the modified PCR-RFLP method. RESULTS: The animals were separated into 16 phenotypes by preoperative PCR-RFLP results, and cryopreserved tracheal allografts transplanted into 8 animals. PCR-RFLP analysis of graft epithelia at 10 days after transplantation showed the donor blood phenotype and analysis of graft epithelia taken from the animals that survived more than 20 days after operation showed the recipient blood and epithelial phenotype. CONCLUSIONS: The donor epithelia in the grafts were no longer present within about 20 days after transplantation. The recipient epithelia migrated gradually from the anastomotic site, and the regenerated epithelia that are of recipient origin covered the allograft within about 50 days after transplantation.

Anastomosis, Surgical↗
PubMed1998

Activation of mitogen-activated protein kinases and activator protein-1 in myocardial infarction in rats.

OBJECTIVE: The purpose of this study was to examine the activation of mitogen-activated protein kinases (MAPK) plus activator protein-1 (AP-1) and nuclear factor-kB (NF-kB) DNA binding activities, all of which seem to be important in a signal transduction cascade upstream of the increased level of mRNA expression observed after myocardial infarction. METHODS: Myocardial infarction was produced in Wistar rats. The activities of MAPKs in the ischemic region were measured using an in-gel kinase method or an in vitro kinase method. AP-1 and NF-kB binding was determined using an electrophoretic mobility shift assay. Levels of transforming growth factor beta-1(TGF-beta-1) and collagen I and III mRNAs were analyzed by Northern blot hybridization. RESULTS: p42 Extracellular signal-regulated kinase (ERK), p44ERK and p38MAPK activities increased 5.2-fold, 4.3-fold and 1.9-fold (P < 0.01), respectively, at 5 min after coronary artery ligation but returned to normal levels by 30 min. p55c-Jun NH2-terminal kinase (JNK) and p46JNK activities increased 4.0-fold and 3.2-fold (P < 0.01), respectively, at 15 min and returned to normal levels by 24 h after ligation. AP-1 DNA and NF-kB binding activities increased 8.7-fold and 7.1-fold (P < 0.01), respectively, at 3 days but returned to normal levels by 7 days after ligation. Interestingly, analyses of the levels of TGF-beta-1, collagen I and III mRNAs revealed increases of 6.3-fold, 15.2-fold and 12.0-fold (P < 0.01), respectively, at 1 week after myocardial infarction. CONCLUSIONS: Myocardial ischemia increased MAPK activities, which were followed by enhancement of AP-1 and NF-kB DNA binding activity in areas of myocardial infarction in rats. These signal transduction mechanisms may contribute to the myocardial ischemia and injury associated with myocardial infarction by causing an increased expression of TGF-beta-1 mRNA, collagen I and III in the area.

Animals↗
PubMed1998

Experimental study of tracheal allotransplantation with cryopreserved grafts.

OBJECTIVE: Tracheal reconstruction is necessary in patients with extensive tracheal stenosis caused by neoplasm, trauma, and congenital disease. We investigated the possibility of tracheal allotransplantation with cryopreserved grafts in a canine model. METHODS: A seven-ring section of thoracic trachea was removed in 19 adult mongrel dogs. In group A (n = 4), a five-ring tracheal autograft was implanted. In group B (n = 6), a five-ring allograft was implanted without immunosuppression. In group C (n = 9), a five-ring cryopreserved tracheal allograft was implanted without immunosuppression. Omentopexy wrapping around the grafts and both anastomotic sites was used in all animals. RESULTS: All grafts survived without any evidence of atrophy or stenosis in group A. All animals in group B died of severe airway obstruction within 1 month, and postmortem examination of these grafts showed epithelial defect and necrotic tracheal cartilage in the scar tissue. In group C, no animals died of asphyxia caused by severe stenosis of the grafts. The graft epithelium was no longer present 20 days after transplantation, and the graft was covered with regenerated epithelium within about 60 days after the operation. CONCLUSION: These findings show that cryopreserved tracheal allografts can be transplanted by means of omentopexy without immunosuppression and that cryopreservation may reduce tracheal allogenicity.

Animals↗
PubMed1998

Androgen metabolism in cultured rat renal inner medullary collecting duct (IMCD) cells.

Although the stimulations of renal hypertrophy and renal erythropoietin production have been well-known androgen effects in the kidney, recent investigative progresses are further providing good evidences for androgen-regulated gene productions of key enzymes or local hormone substrates important to renal cell metabolisms and tubular functions in mouse or rat proximal tubules, respectively. It has been also reported that testosterone restores vasopressin receptors in medullary collecting ducts of the ageing rat and improves a urinary concentrating ability. Therefore in the present study we examined a metabolic pathway of androgens in cultured rat renal IMCD cells, which finally determine a urinary composition and volume. IMCD cells cultured from kidneys of male Wistar rats weighing about 200 g were incubated with serum-free culture media containing 4 nM [3H] testosterone or [3H] androstenedione for 2-48 h. Radioactive compounds in incubation media were then separated by reverse-phase high-pressure liquid chromatography (HPLC) and identified mainly on the basis of comparison of retention times of standard materials on HPLC. The main metabolites identified in testosterone or androstenedione incubation experiment were 5 alpha-dihydrotestosterone or 5 alpha-androstanedione, respectively. 5 alpha-Reductase inhibitor, MK 906, effectively inhibited the formations of these Ring A reduced metabolites. These results may suggest that rat renal IMCD cells possess 5 alpha-reductase activity, thereby converting androgens into their biologically active forms in vivo.

5-alpha Reductase Inhibitors↗