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Biomedical subjects

Y Oshima

Publications and source records attributed to Y Oshima.

At least 109 records · Page 6Linked to original sources

Classic Blalock-Taussig shunt in neonates.

BACKGROUND: The choice of palliative procedure for neonates with congenital cyanotic heart defects remains controversial. Several reports have questioned whether the classic Blalock-Taussig shunt is adequate in neonates, because it shows a high rate of mortality and early shunt failure. The purpose of this study is to evaluate the early and late results of classic Blalock-Taussig shunt in neonates. METHODS: From December 1981 to December 1996, 31 neonates underwent a classic Blalock-Taussig shunt. Mean age at operation was 15.9 days (range, 2 to 28 days), and mean body weight was 3214 g (range, 2229 to 4468 g). The major diagnoses were pulmonary atresia with intact ventricular septum (6 patients) and with ventricular septal defect (4), univentricular heart (6), tricuspid atresia (5), tetralogy of Fallot (4), transposition of the great arteries (3), and double outlet right ventricle (3). RESULTS: There were no early deaths. There was one early shunt failure. The patient underwent a replacement of Blalock-Taussig shunt by vascular graft on the 1st postoperative day. Two patients with non-confluent central pulmonary artery underwent a contralateral modified Blalock-Taussig shunt on the 22nd and 42nd postoperative day, respectively. There were two late deaths before the definitive repair was performed. Twelve patients required an additional shunt operation. The mean interval between the initial and the second shunt procedure was 27.7 months (range, 6 to 67 months). Ten patients underwent definitive operation and the mean interval to that procedure was 55.5 months (range, 14 to 121 months). Shunt patency was 94.7+/-5.1% at 3 years. The freedom from cardiac event (cardiac deaths or repeat shunting procedure) was 80.5+/-7.1% at 1 year and 54.9+/-9.4% at 3 years. CONCLUSIONS: The classic Blalock-Taussig shunt has a low operative mortality and has provided excellent long-term palliation in the neonate. We conclude that a classic Blalock-Taussig shunt should be considered a reasonable choice in neonates requiring a palliative procedure for congenital cyanotic heart defects.

Heart Defects, Congenital↗

[Macular morphologic reconstruction and visual recovery in patients following macular hole surgery].

PURPOSE: To examine the characteristics of retinal reconstruction at the macula following macular hole surgery and to assess the impact of postoperative macular morphological changes on the visual outcome. METHODS: A prototype of the scanning retinal thickness analyzer (RTA) was used to obtain optical section images at the macula in 53 eyes of 52 patients who underwent macular hole surgery between April 1994 and July 1997. The mean age of participants was 64.7 years. At the time of RTA examination, macular hole was biomicroscopically closed in 49 eyes (91%) and unclosed in 5 eyes (9%). RESULTS: There were 5 types of cross-sectional images of postoperative maculae: normal foveal depression [19 eyes (36%)], crater-like fovea formation [12 eyes (22%)], flattened fovea [8 eyes (15%)], fovea with abraded retinal pigment epithelium [9 eyes (17%)], and persistant macular hole [5 eyes (9%)]. Central macular thickness measured by RTA was 165 +/- 39 (mean +/- standard dereation) microns in the normal foveal depression group, 210 +/- 67 microns in the crater-like fovea formation group, and 300 +/- 50 microns in the flatened fovea group. There were statistically significant differences (p < 0.01) between groups. Postoperative visual acuity was significantly different (p < 0.01) between these three groups, and central macular thickness was highly correlated with postoperative visual acuity (R = 0.70). CONCLUSION: Visual recovery following macular hole surgery is closely associated with the retinal reconstruction at the macula.

Aged↗

Growth characteristics of T-cell tropic HIV-1 vpu gene mutants in human peripheral blood mononuclear cells.

A mutant designated NL-E65, which lacks the expression of entire vpu gene, was constructed from T-cell tropic wild-type (wt) human immunodeficiency virus type 1 (HIV-1) clone and monitored for its replication property in human cells, along with a mutant NL-Ss which expresses a C-terminal truncated Vpu. The mutant NL-Ss could grow in two cell lines and in all peripheral blood mononuclear cell (PBMC) preparations to some extent, with kinetics similar to those of wt virus. Likewise, the mutant NL-E65 exhibited a replication property typical to the vpu mutant in the two cell lines and in all PBMC cultures, growing at a low level. Along with the results previously reported, these data indicate that HIV-1 Vpu is dispensable for virus replication in any of the types of cells so far tested.

Acquired Immunodeficiency Syndrome↗

VEGF-dependent signaling in retinal microvascular endothelial cells.

We examined the effect of vascular endothelial growth factor (VEGF) on intracellular signal transduction pathways using isolated bovine microvascular endothelial cells (BREC). When cell growth was determined by [3H]thymidine incorporation, it was significantly stimulated by VEGF stimulation. In situ hybridization results also demonstrated that c-fos expression was enhanced by the stimulation. Although BREC expressed Flt-1 and Flk-1 as VEGF receptors at similar levels, VEGF stimulation preferentially enhanced the activity of Flt-1 tyrosine kinase. This stimulation initiated an increase in the level of GTP-form Ras and the activation of mitogen activated protein kinase (MAPK). On the other hand, BREC expressed the Janus kinase (Jak) family members Jak1, Jak2, and Tyk2, and the signal transducers and activators of transcription (Stat) family members Stat1, Stat3, and Stat6. These molecules were tyrosine phosphorylated under culture conditions used, and the phosphorylation of Tyk2 and Stat6 was specifically enhanced by VEGF stimulation. These results demonstrate that, in addition to Ras/MAPK pathways, the Flt-1/Tyk2/Stat6 pathway is important in VEGF signaling in BREC. These signal transduction systems may regulate the growth of retinal endothelial cells.

Animals↗

Na+,K+-ATPase activity in cultured bovine retinal pigment epithelium.

PURPOSE: To characterize electrogenic Na+,K+-ATPase activity in cultured bovine retinal pigment epithelium (RPE). METHODS: Cultured bovine RPE cells from passages 3 through 5 were dissociated enzymatically. Na+,K+-adenosine triphosphatase (ATPase)-activated currents (Ip) were measured by using a nystatin perforated-patch recording technique under voltage- clamp conditions. In the presence of suitable blockers for known voltage-dependent Na+, K+, and Ca2+ conductances, the Ip was activated in a concentration-dependent manner by adding K to the external solution. RESULTS: The median effective concentration (EC50) and Hill coefficient for external K+ concentration ([K+]o) were 1.06 mM and 2.55, respectively. The Ip showed no significant voltage dependency. A large outward shift of holding current was observed when [Na+]o, was removed. In the presence of [Na+]o, the addition of K+ to the external solution induced Ip, even when the internal solution did not contain Na+, suggesting the existence of a continuous Na+ influx across the plasma membrane in the presence of [Na+]o,. When Na+ was removed from the external and internal solutions, a transient Ip was observed, indicating that the transient Ip was activated by the intracellular residual Na+. The Ip was concentration-dependently suppressed by ouabain. The 50% inhibitory concentration (IC50) value and Hill coefficient for ouabain were 5.98 microM and 1.12, respectively. CONCLUSIONS: The present study is the first to reported the functional properties of electrogenic Na+,K+-ATPase activity in cultured bovine RPE.

Animals↗

Suppression of HIV-2 replication by HIV-1 gag mutants.

Gag gene mutants of human immunodeficiency virus type 1 (HIV-1) were analyzed for their potentials of inhibiting the replication of wild-type (wt) HIV-2, the second AIDS virus, in a single-round of viral replication. Of twenty-two HIV-1 gag mutants examined, seven were found to efficiently interfere with the replication of wt HIV-2. Some mutants, which can suppress the replication of wt HIV-1, did not show this inhibitory effect. These mutants were defective at the late phase of viral replication. A mutant designated NL-C1a was demonstrated to be very effective against the replication of HIV-1 and HIV-2 in monocytic cells as well as in lymphocytic cells.

CD4-Positive T-Lymphocytes↗

Enhancement of NO production in activated macrophages in vivo by an antimalarial crude drug, Dichroa febrifuga.

The effect of an antimalarial crude drug, Dichroafebrifuga Lour. on nitric oxide (NO) production in bacillus Calmette Guérin-induced mouse peritoneal macrophages activated by lipopolysaccharide was investigated. The NO production was significantly enhanced by an oral administration of a MeOH extract of D. febrifuga. Febrifugine (1) was isolated as the main active compound, and the activation was dose-dependent in the dosage range of 0.1-1 mg/kg/day.

Animals↗

The potential of various HIV-1 mutants to inhibit the replication of wild-type virus.

We have previously demonstrated that many of gag mutants of human immunodeficiency virus type 1 (HIV-1) inhibited the replication of wild-type (wt) HIV-1. In this study, various HIV-1 mutants were systematically analyzed with respect to their ability to suppress the replication of wt HIV-1. Sixteen mutants of all eight HIV-1 genes other than gag were evaluated for their inhibitory effects. Only an env mutant designated NL-Hi efficiently interfered with the replication of wt HIV-1 in a single round of infection. The NL-Hi did not affect the late replication processes of wt virus, including transcription, translation, and assembly/release. Virions produced in the presence of the mutant Env were defective for the viral entry process in the early phase of HIV-1 replication cycle.

Cell Line↗

Retinal functional change caused by adenoviral vector-mediated transfection of LacZ gene.

We examined the effect of insertion of an exogenous gene on retinal function to assess the rationale of adenoviral vector-mediated gene transfer for future gene therapy. An adenoviral vector expressing bacterial LacZ (AdCALacZ) was injected into the eyes of adult rats either intravitreally (group A) or subretinally (group B), and the gene expression and retinal function were thus examined at different time points after gene transfer for 3 weeks. X-Gal histostaining showed that neural retinal cells were transfected in group A and that retinal pigment epithelial cells were transfected in group B. The gene transfer was more efficient in group B (54.4% of the fixed retinal area was stained) than in group A (10.4%). The electroretinogram (ERG) revealed retinal dysfunction in the AdCALacZ-transfected rats even at the stage in which the histological damage was not apparent by electron microscopy and immunohistochemical studies for cytokeratin, S-100 protein, and glial fibrillary acidic protein. The ERG change was correlated with the intensity of inflammation, and retinal function recovered to the original level by 3 weeks, along with a diminution of inflammation. Functional changes were more evident in eyes treated with AdCALacZ than in those infected with adenoviral vector with no exogenous gene; however, no histological difference was observed between these groups, indicating that the insertion of exogenous gene itself affects retinal function. The results showed that different kinds of retinal cells could be gene-transferred by an adenoviral vector, depending on the application method. The retinal dysfunction caused by each adenoviral transfection method was caused by inflammation and the insertion of exogenous gene, and this retinal dysfunction was recoverable. In future gene therapy, special attention should be given to the method of exogenous gene insertion in the retina.

Adenoviridae↗

Novel quartz flow-cell as a post-column photochemical reactor for high-performance liquid chromatography.

The construction of a new post-column photochemical reactor with quartz flow cells in series for high-performance liquid chromatography (HPLC) is described. The performance of the new reactor was compared with a conventional open tubular PTFE coil reactor. The sensitivity, accuracy and precision obtained with both reactors are comparable. The new reactor has the obvious advantages of smaller cell volume as well as inertness and resistance to not only light and heat produced by the UV lamp, but also to organic solvents in the mobile phases, which results in greatly improved durability, reduced peak broadening and shorter chromatographic run times. Application of the new reactor to the fluorescence detection of DU-6859a, a new fluoroquinolone antimicrobial agent, in human serum is reported.

Anti-Infective Agents↗

Recombinant human granulocyte colony-stimulating factor (G-CSF) combined conditioning regimen for allogeneic bone marrow transplantation (BMT) in standard-risk myeloid leukemia.

We previously suggested that using a combined conditioning regimen including rhG-CSF with allogeneic BMT in refractory AML and CML in blast crisis might reduce the rate of relapse and improve disease-free survival, without any major side effects. In this study, we used the same protocol for 10 AML patients in complete remission (CR) and 6 CML patients in the chronic phase (CP). We compared disease-free survival as well as toxic side effects of the regimen with 6 AML patients in CR and 6 CML patients in CP treated with chemoradiotherapy without G-CSF. The conditioning regimen consisted of TBI and high-dose AraC. RhG-CSF was infused continuously at a dose of 5 microg/kg/day, starting 24 hr before the initial dose of total body irradiation (TBI) until the end of AraC therapy. In all 28 cases, there were no early stage deaths due to regimen-related toxicity (RRT). None of the 10 AML cases treated with the G-CSF combined regime relapsed. In 6 AML cases treated conventionally without G-CSF, one patient died of infection and another relapsed. There were no relapses in either CML group. In the combined G-CSF group, one patient died of interstitial pneumonitis 48 days after BMT, while the rest of the CML cases are still alive. There were no relapses with rhG-CSF and no serious adverse effects in terms of RRT, acute graft vs. host disease (GVHD), or leukocyte recovery.

Adult↗

[Pulmonary artery sling with tracheal stenosis--primary repair in infancy].

Between 1984 and 1996 five infants underwent surgical repair of pulmonary artery sling associated with severe congenital tracheal stenosis. All infants had symptoms of severe respiratory distress and three of them required ventilator support preoperatively ages ranged from 2 to 11 months (mean age 6 months). Complete tracheal rings were present in all patients as an associated lesion and right upper lobe tracheal bronchus in 3 patients. The length of tracheal stenosis ranged from 18 to 45 mm (median 40 mm). Three had associated intracardiac anomalies (Scimitar syndrome (1), VSD (1), double-outlet right ventricle with VSD (1), double-outlet right ventricle with pulmonary hypertension (1)). Surgical intervention was carried out through a right thoracotomy (1) or median sternotomy (4). Cardiopulmonary bypass (CPB) was used in 3 patients and extracorporeal membrane oxgenator (ECMO). In 1. All infants had reimplantation of the left pulmonary artery into the main pulmonary artery left anterior to the trachea. Four patients underwent simultaneous tracheoplasty using costal cartilage grafts and one had complete resection of obstructed trachea between the right upper lobe tracheal bronchus and carina. The length of resected trachea was about 30% of the entire length of the trachea. Three infants underwent simultaneous intracardiac repair. There was no hospital death. All were weaned from ventilatory support and extubated on 1 to 16 months (mean 4, 5 months) postoperatively. AS an additional procedure, aortopexy, removal of granulation tissue or balloon dilatation of the trachea were carried out in one patient each following tracheoplasty using cartilage grafts. There was one late death at 1 year postoperatively. Three of 4 survivors are doing well with no stridor. We adonostridor. We adovocate 1) early aggressive primary repair of pulmonary artery sling with tracheal stenosis, 2) concomitant repair of tracheal lesion and intracardiac anomalies whenever possible, 3) application of CPB or ECMO to avoid cumbersome intubation technique, and 4) utmost effort to perform tracheal resection and end-to-end anastomosis.

Anastomosis, Surgical↗

[Successful staged repair of corrected transposition of great arteries and mitral atresia associated with double aortic arch].

We report a rare case of corrected transposition of great arteries and mitral atresia associated with double aoric arch. The patient showed polypnea and cyanosis soon after birth. She underwent balloon atrioseptostomy at the age of 18 days and pulmonary artery banding (PAB) at 24 days. But she showed severe persistent stridor after PAB. Esophagography and left counter-current aortography revealed double aortic arch. At the age of 49 days, division of the left lesser arch and ligation of patent ductus arteriosus were performed through left lateral thoracotomy. Stridor disappeared completely following operation. She underwent total cavopulmonary connection using a 18 mm Gore-Tex graft as intraatrial conduit concomitant with pacemaker implantation at the age of 8 years. Postoperative course was uneventful. To our knowledge, this is the first successful case report of surgical correction of corrected transposition of great arteries and mitral atresia associated with double aoric arch.

Aorta, Thoracic↗

The Tup1-Ssn6 general repressor is involved in repression of IME1 encoding a transcriptional activator of meiosis in Saccharomyces cerevisiae.

Ime1 plays a pivotal role in the initiation of meiosis in a/alpha diploid cells of Saccharomyces cerevisiae. In the absence of glucose and nitrogen, IME1 expression is greater in a/alpha cells than in either a or alpha cells and therefore only a/alpha, but not a/a or alpha/alpha, cells are committed to sporulation. It is known that IME1 expression is positively regulated by Mck1, Rim1, Ime4 and the Swi-Snf complex but other factors may also be involved. In addition, Rme1 is assumed to repress IME1 expression. To provide more details of the repression of expression of IME1, we have isolated mutants in which the IME1p-PHO5 fusion gene integrated at the ura3 locus is expressed in alpha cells under nutritionally rich conditions. We found that mutations occurred in TUP1, SSN6, SIN4 and RGR1, among which TUP1 and SSN6 were identified for the first time as negative regulators of IME1 expression. Deletion of the Rme1-binding site from the IME1 promoter did not result in activation of the expression of IME1 under nutritionally rich conditions, suggesting that Rme1 does not function as a DNA-binding protein with the Tup1-Ssn6 repression complex. We also demonstrated that the 294-bp fragment from nucleotide position -914 to -621 and the 301-bp fragment from nucleotide position -1215 to -915 of the IME1 promoter region contain elements acting as URS and UAS in TUP1+ and tup1 mutant cells, respectively. These findings indicate that IME1 is negatively regulated by the Tup1-Ssn6 repressor complex through two distinct upstream regions in conjunction with unidentified DNA-binding proteins.

Base Sequence↗

Synergistic effect of electric pulses and bleomycin on cultured rabbit subconjunctival fibroblasts.

BACKGROUND: The combined effect of electric pulses (EP) and antiproliferative agents on the proliferation of rabbit Tenon's capsule fibroblasts was investigated. METHODS: Rabbit Tenon's capsule fibroblasts were cultured. Some of these cells were exposed to various intensities of EP alone (500-2500 V/cm). Other cells were then exposed for 30 min to an antiproliferative agent: bleomycin (BLM; 0.0005-50 mumol/l), mitomycin C (MMC; 0.0005-50 mumol/l), 5-fluorouracil (5-FU; 0.05-5000 mumol/l), or streptomycin (SM; 0.0005-50 mumol/l) with or without EP (2000 V/cm, 99 mus, eight pulses). Cell proliferation was assessed by cell counting on day 3 and by a 3H-thymidine uptake assay. DNA fragmentation was assessed by flow-cytometric analysis and agarose gel electrophoresis. RESULTS: A significant reduction in the cell number was observed only at 2500 V/cm (P < 0.05). BLM, MMC and 5-FU treatment inhibited cell proliferation in a dose-dependent manner either with or without EP (ID50: BLM alone, 0.029 mumol/l; BLM and EP, 0.00022 mumol/l; MMC alone, 41.6 mumol/l; MMC and EP, 27.5 mumol/l; 5-FU alone, 1045 mumol/l; 5-FU and EP, 690.2 mumol/l; P < 0.05). EP treatment induced an inhibitory effect of BLM on cell proliferation which was 100 times more prominent than BLM alone (0.0005 mumol/l of BLM alone 103.4 +/- 4.4%, 0.0005 mumol/l of BLM and EP 26.0 +/- 4.4%; P = 0.021). BLM treatment with EP also augmented the apoptotic-like DNA fragmentation in both a flow-cytometric DNA histogram and agarose gel-electrophoresis. CONCLUSION: EP treatment enhanced the inhibitory effect of BLM on the cell proliferation of Tenon's capsule fibroblasts of rabbits. The combination of electric pulses and antiproliferative drug treatments may therefore reduce the necessary dose of antiproliferative agents in filtering surgery.

Animals↗

Complete epiretinal membrane separation in highly myopic eyes with retinal detachment resulting from a macular hole.

PURPOSE: Epiretinal membranes (ERMs) in highly myopic eyes may result in macular holes and subsequent retinal detachment. However, removing friable, thin ERMs from detached retinas is often difficult. We report the efficacy of a diamond-dusted silicone cannula in the removal of ERMs from detached retinas. METHODS: Seventeen consecutive highly myopic eyes (16 patients) with retinal detachment underwent pars plana vitrectomy with gas tamponade. Peeling of the ERM adjacent to the macular hole was performed using either conventional tools (n = 11) or a diamond-dusted silicone cannula (n = 6). The rate of complete membrane peeling and the effect of membrane removal on the anatomic success rate were compared between groups. RESULTS: Retinal reattachment occurred in 13 (92.9%) of the 14 eyes in which the ERM was removed completely; redetachment occurred in the other three eyes, with further surgical interventions in two eyes. The reattachment rate was significantly higher (P = .005) when ERM removal was complete than when there was residual ERM. In the initial surgery, the ERM was successfully removed in all 6 eyes (100%) in the diamond-dusted silicone cannula group and in 5 of 11 eyes (45.5%) in the conventional group (P = .041); the reattachment rate was 100% in the diamond-dusted silicone cannula group and 45.5% in the conventional group (P = .005). When a second surgery was performed, the use of the diamond-dusted silicone cannula was also better than conventional tools for removing the residual ERMs, resulting in retinal reattachment. CONCLUSION: In highly myopic eyes with a macular hole and subsequent retinal detachment, complete ERM removal is closely related to successful retinal reattachment. The diamond-dusted silicone cannula appears to be more effective than conventional tools for removing ERM and may increase the anatomic success rate. Because of the limitations of a small series, a prospective, randomized trial is required to confirm the current beneficial results of using a diamond-dusted silicone cannula.

Aged↗

Growth of the subclavian artery and the anastomosis in Blalock-Taussig shunt: absorbable versus nonabsorbable suture.

BACKGROUND: We evaluated the growth of Blalock-Taussig shunts placed with absorbable suture by cineangiographic findings and long-term results and compared them with those in an earlier group of patients in whom we used nonabsorbable suture. METHODS: Eighty-one patients had postoperative cineangiography 1 year or more after a Blalock-Taussig shunt procedure. From September 1985 to December 1994, 40 patients (group I) underwent a Blalock-Taussig shunt procedure with the use of absorbable polydioxanone suture, and from January 1980 to August 1989, 41 (group II) underwent the same operation with nonabsorbable polypropylene suture. Cineangiograms were reviewed to assess shunt patency and growth of the subclavian arteries and the subclavian artery-pulmonary artery anastomoses. RESULTS: At the Blalock-Taussig shunt operation, mean outer diameters of the subclavian artery and the anastomosis in group I were 3.8 +/- 0.1 mm and 4.1 +/- 0.1 mm, respectively and 3.9 +/- 0.1 mm and 4.0 +/- 0.1 mm in group II. The mean inner diameters of the subclavian artery and the anastomosis measured in postoperative cineangiograms were 7.9 +/- 0.5 mm and 4.6 +/- 0.2 mm, respectively in group I and 6.6 +/- 0.4 mm and 3.1 +/- 0.2 mm in group II. The diameters of both the subclavian artery (p < 0.05) and the anastomosis (p < 0.001) were significantly greater in group I than in group II. Five years after operation, 71.1% +/- 7.4% of patients in group I and 54.8% +/- 8.0% in group II had good palliation. CONCLUSIONS: The use of absorbable polydioxanone suture has an advantage in terms of growth of the diameters of the subclavian artery and the anastomosis in a Blalock-Taussig shunt and may improve the long-term results after this shunt operation in infancy.

Absorption↗

The features of contralateral manifestations after the repair of unilateral inguinal hernia.

BACKGROUND/PURPOSE: Routine contralateral exploration in infants and children with unilateral clinical inguinal hernia is performed by many surgeons in a selected population of patients based on a presumed high incidence of patent processus vaginalis. Our purpose is to report the actual incidence of contralateral manifestations in infants and children after the repair of unilateral inguinal hernia. METHODS: From July 1985 through December 1995, 1,052 infants and children with unilateral inguinal hernia or hydrocele were treated in our hospital without contralateral exploration. Among them, 1,001 patients (95.2%) were followed up for 1 to 11 years to determine if contralateral hernia developed after unilateral inguinal herniorrhaphy. RESULTS: The overall incidence of contralateral hernia was 11.6% (116 of 1,001). In boys, the incidence was 13.1%, 13.7%, and 11.7% in those under 1 year, under 2 years of age, and in total, respectively. In girls, the incidence was 9.6%, 13.9%, 11.3%, in those under 1 year, under 5 years of age, and in total, respectively. The side of the initial repair did not influence the subsequent development of contralateral inguinal hernia. In children with hydrocele, the incidence of contralateral hernias was lower (7.6%). In girls with sliding hernias the contralateral occurrence was 12.5%. CONCLUSION: Given this low incidence of contralateral hernia after unilateral inguinal herniorrhaphy, the authors do not recommend contralateral exploration for infants and children with unilateral inguinal hernia.

Adolescent↗