Biomedical subjects

Y Oshima

Publications and source records attributed to Y Oshima.

At least 91 records · Page 5Linked to original sources

PubMed1999

Optical cross-sectional assessment of the macula by retinal thickness analyzer in optic disk pit maculopathy.

PURPOSE: To assess the morphologic changes in optic disk pit maculopathy. METHOD: Case report. A 45-year-old woman with optic disk pit maculopathy in the left eye was examined with the scanning retinal thickness analyzer before and after vitrectomy with intravitreal gas tamponade. RESULTS: Preoperatively, optical cross-sectional retinal thickness analyzer images clearly demonstrated the extent of retinoschisis and outer layer detachment in the macula. Postoperatively, the retinal thickness analyzer images showed that retinal thickening decreased as the intraretinal fluid in the schisis cavity was absorbed and then gradually decreased further as the outer layer detachment in the fovea resolved. CONCLUSIONS: Scanning retinal thickness analyzer can be used to diagnose and monitor the structural changes of the macula lesion in optic disk pit maculopathy. Vitrectomy with gas tamponade may be effective for treating this disease.

Diagnostic Techniques, Ophthalmological↗

PubMed1999

Intrahepatic venovenous shunting to an accessory hepatic vein after Fontan type operation.

Because there are various types of systemic venous connections in patients with visceral heterotaxy, unanticipated abnormal systemic venous channels may pose additional problems after a Fontan type operation. We report a case of severe cyanosis caused by anomalous intrahepatic venovenous fistula to an accessory hepatic vein early after total cavopulmonary anastomosis.

Child↗

PubMed1999

Surgery for mitral valve disease in the pediatric age group.

OBJECTIVES: We reviewed a 20-year experience with the surgical treatment of mitral valve disease in the pediatric age group at our institution with 2 objectives: to clarify the long-term results over the last 2 decades and to evaluate the recent advances in mitral valve operation in children. METHODS: Since December 1978, 56 patients have undergone a total of 36 mitral valve repairs and 30 mitral valve replacements. Associated cardiac anomalies were present in 46 patients (82%), and concurrent repair of associated lesions was performed in 37 patients (66%). The age of the patients ranged from 3 months to 15 years (mean, 3.6 years) at mitral valve repair, and ranged from 2 months to 16 years (mean, 5.7 years) at mitral valve replacement. Mean follow-up period was 92.0 months (range, 1-235 months). RESULTS: There were 2 hospital deaths and 2 late deaths in patients who underwent mitral valve repair. Reoperation was performed in 4 patients. Three of these patients underwent mitral valve replacement because of residual mitral incompetence. No hospital deaths occurred in patients who underwent mitral valve replacement. Two late deaths occurred after mitral valve replacement. Six patients had a total of 10 episodes of prosthetic valve thrombosis. Thrombolytic therapy with urokinase was successful in all episodes without serious complications. Five patients required reoperations 49 to 141 months (mean, 78.4 months) after the initial valve replacement for relative prosthetic valve obstruction as the result of somatic growth. A valve 2 or 3 sizes larger than the original prostheses was inserted without death. Actuarial survival and freedom from cardiac events at 10 years after the operation were 87.2% and 72.7% in children who underwent mitral valve repair, and 90.3% and 67.3% for those children who underwent mitral valve replacement. CONCLUSIONS: The current risk of mitral valve operation in the pediatric age group is low, and the long-term results are satisfactory, irrespective of severe deformation of the mitral valve apparatus and associated complex cardiac anomalies.

Actuarial Analysis↗

PubMed1999

The first evidence of paralytic shellfish toxins in the fresh water cyanobacterium Cylindrospermopsis raciborskii, isolated from Brazil.

The blooms of toxic cyanobacteria (blue-green algae) are causing problems in many countries. During a screening of toxic freshwater cyanobacteria in Brazil, three strains isolated from the State of Sao Paulo were found toxic by the mouse bioassay. They all were identified as Cylindrospermopsis raciborskii by a close morphological examination. Extracts of cultured cells caused acute death to mice when injected intraperitoneally after developing neurotoxic symptoms which resembled to those caused by paralytic shellfish toxins. The analysis of the sample by HPLC-FLD postcolumn derivatization method for paralytic shellfish toxins resulted in the detection of several saxitoxin analogs. To avoid being misled by false peaks, the sample was reanalyzed after purification and also under the different postcolumn derivatizing conditions. Finally, the newly developed LC-MS method for paralytic shellfish toxins was applied to unambiguously identify the toxins. One isolate produced neosaxitoxin predominantly with saxitoxin as a minor component. The other two showed identical toxin profiles containing saxitoxin and gonyautoxins 2/3 isomers in the ratio of 1:9. This is the first evidence of paralytic shellfish toxins in this species and also the occurrence of the toxin producing cyanobacterium in South American countries.

Animals↗

PubMed1999

Methicillin-resistant Staphylococcus aureus infections after scleral buckling procedures for retinal detachments associated with atopic dermatitis.

OBJECTIVE: To determine the incidence and the clinical course of methicillin-resistant Staphylococcus aureus as a cause of acute-onset infections in patients with atopic dermatitis after a scleral buckling procedures. DESIGN: A retrospective chart review. PARTICIPANTS: Two hundred eighty-seven patients (293 eyes) who underwent scleral buckling procedures to treat rhegmatogenous retinal detachments at either Osaka Rosai Hospital or Osaka University Medical School between July 1, 1995, and June 30, 1997, participated. Of these, 32 eyes (10.9%) were associated with atopic dermatitis. INTERVENTION: Demographic and clinical data were abstracted from patients' medical records. MAIN OUTCOME MEASURES: The incidence, clinical features, and management of postoperative infections associated with methicillin-resistant S. aureus were studied. RESULTS: Methicillin-resistant S. aureus infection after scleral buckling procedures was identified in 6 (18.8%) of 32 eyes of patients with atopic dermatitis but in only 1 (0.4%) of the other 261 cases without atopic dermatitis (P < 0.001). The average interval from the scleral buckling procedures to the initial onset of infection was 8.3 +/- 9.1 days (range, 2-28 days). Bacterial infection and inflammation were controlled in four eyes by prompt removal of the infected buckle in combination with vancomycin administration. In the other three eyes, however, repeat intravitreous injections of vancomycin or emergent vitrectomies were required because of the development of endophthalmitis. CONCLUSIONS: Methicillin-resistant S. aureus is an important causative pathogen of scleral buckling infections, particularly in patients with retinal detachment associated with atopic dermatitis. Preoperative evaluation and intraoperative attention to contamination are recommended to prevent methicillin-resistant S. aureus infections in these patients.

Acute Disease↗

PubMed1999

The comparative benefits of glaucoma filtering surgery with an electric-pulse targeted drug delivery system demonstrated in an animal model.

PURPOSE: To evaluate the safety and effectiveness of glaucoma filtering surgery performed with the adjunctive use of bleomycin administered in conjunction with electric pulses (EP). DESIGN: Experimental study in rabbits. CONTROLS AND METHODS: Trabeculectomies were performed on pigmented rabbits (2 to 2.5 kg) using the following adjunctive treatments: 5 microM of topical bleomycin and EP (5V, 50 msec, 8 pulses) (group A: B+E+, n=15); bleomycin but no EP (group B: B+E-, n=15); 5 ,uM mitomycin C (MMC) and EP (group C: M+E+, n= 10); MMC but no EP (group D: M+E-, n=10); EP alone (group E: E+, n=10); and no adjunctive treatment (group F: E-, negative control, n=10). MAIN OUTCOME MEASURES: Intraocular pressure (IOP) was measured regularly for 60 days after the operation. Bleb formation and the condition of the conjunctiva, cornea, and retina were also regularly evaluated. Histologic studies were performed by light microscopy, and retinal functions were evaluated by electroretinography. RESULTS: Postoperative IOP was significantly lower than the preoperative level in all the animals until day 7. However, in groups E and F (the negative control) it returned to the preoperative level after day 7, and in groups B, C, and D after 15 days. The IOP of group A remained lower even on day 40. The average amount IOP was lowered or increased on day 20 was -6.4 mmHg (P < 0.05) in group A; -0.2 mmHg in group B; +1.2 mmHg in group C; and -3.25 mmHg in group D. The survival rate of the filtering blebs on day 20 was significantly higher in group A than in the other groups. Clinical and histologic studies uncovered no pathologic findings in any intra- or paraocular tissues. Electroretinographic evaluation of retinal function in group A showed no apparent change over the 60 days of the study. CONCLUSION: Glaucoma filtering surgery in rabbits with the adjunctive use of bleomycin in conjunction with EP significantly lowered IOP for up to 40 days without clinically, morphologically, or functionally harming intraocular tissues.

Animals↗

PubMed1999

Cell-dependent replication potentials of HIV-1 gag mutants.

An infectious molecular clone of human immunodeficiency virus type 1 (HIV-1), designated pNLaiKH, which is tropic for both lymphocytic and monocytic cells, was constructed. To study the early function of HIV-1 Gag proteins in two types of cells, the mutations known to give host cell-dependent early defects were introduced into pNLaiKH, and the replication potentials and defective replication sites in the cells of the resultant mutants were monitored. All mutants grew in some lymphocytic cells, but not at all in monocytic cells. A nucleocapsid mutant was found to be defective at an early replication phase in all the cell lines to various extent, as expected. In contrast, a matrix mutant and a capsid mutant displayed a replication defect in a producer-cell-dependent manner. These results demonstrated that complex interactions of cell factors and Gag proteins are involved in an early process of HIV-1 replication.

Cell Line↗

PubMed1999

Isolation of iron-oxidizing bacteria from corroded concretes of sewage treatment plants.

Thirty-six strains of iron-oxidizing bacteria were isolated from corroded concrete samples obtained at eight sewage treatment plants in Japan. All of the strains isolated grew autotrophically in ferrous sulfate (3.0%), elemental sulfur (1.0%) and FeS (1.0%) media (pH 1.5). Washed intact cells of the 36 isolates had activities to oxidize both ferrous iron and elemental sulfur. Strain SNA-5, a representative of the isolated strains, was a gram-negative, rod-shaped bacterium (0.5-0.6x0.9-1.5 microm). The mean G+C content of its DNA was 55.9 mol%. The pH and temperature optima for growth were 1.5 and 30 degrees C, and the bacterium had activity to assimilate 14CO2 into the cells when ferrous iron or elemental sulfur was used as a sole source of energy. These results suggest that SNA-5 is Thiobacillus ferrooxidans strain. The pHs and numbers of iron-oxidizing bacteria in corroded concrete samples obtained by boring to depths of 0-1, 1-3, and 3-5 cm below the concrete surface were respectively 1.4, 1.7, and 2.0, and 1.2 x 10(8), 5 x 10(7), and 5 x 10(6) cells/g concrete. The degree of corrosion in the sample obtained nearest to the surface was more severe than in the deeper samples. The findings indicated that the levels of acidification and corrosion of the concrete structure corresponded with the number of iron-oxidizing bacteria in a concrete sample. Sulfuric acid produced by the chemolithoautotrophic sulfur-oxidizing bacterium Thiobacillus thiooxidansis known to induce concrete corrosion. Since not only T. thiooxidans but also T. ferrooxidans can oxidize reduced sulfur compounds and produce sulfuric acid, the results strongly suggest that T. ferrooxidans as well as T. thiooxidans is involved in concrete corrosion.

Journal Article↗

PubMed1999

Compatibility of Vpu-like activity in the four groups of primate immunodeficiency viruses.

Env-minus mutants of the viruses of major four human and simian immunodeficiency viruses (HIVs and SIVs) were monitored for their progeny virion production upon transfection into the cells, which are dependent on the HIV-1 Vpu for efficient particle release. Of the env mutants of HIV-1 (one mutant), HIV-2/SIVmac (three mutants), SIVagm (one mutant), and SIVmnd (one mutant) examined, the mutant of SIVmnd generated a very low level of progeny virions similar to that by the HIV-1 Vpu-minus mutant. This effect of the mutation was not observed in the cells which are independent on the Vpu for virion release. The Env of SIVmnd efficiently enhanced virion release of heterologous viruses like the HIV-1 Vpu.

Animals↗

PubMed1999

Inhibition of HIV/SIV replication by dominant negative Gag mutants.

There are several major strategies against HIV/AIDS. Of these, the gene therapy is a novel, challenging, and promising one. The target genes, which have been extensively studied for the potential gene therapy of HIV/AIDS, include those of cellular and viral origins. Especially, trans-dominant negative Tat, Rev, Env, Pol, and Gag mutants of HIV have currently attracted considerable attention. In this brief review, we summarize the nature of the HIV/SIV mutants of this category and discuss their future use for gene therapy with special reference to the dominant negative Gag mutants of HIV-1.

Genes, Dominant↗

PubMed1999

Clinical application of a nonpenetrating microvascular stapling device for vascularized free tissue transfer.

It is essential to develop a method that is technically easier and faster to perform microvascular anastomosis. Therefore the authors have utilized a nonpenetrating microvascular stapling device (VCS; Auto Suture, Tokyo, Japan). Eight vascularized free tissue transfers were performed using this stapling device. All of the transferred tissues were grafted successfully. The time required to perform the stapled microvascular anastomosis ranged from 8 to 18 minutes (mean, 12 minutes). Two arterial anastomoses required suture repairs because they could not be repaired with the use of this stapling device due to thickened vessel walls and intimal dissections. The microvascular stapling device proved useful for vascularized free tissue transfers, but the vessels suitable for this technique should be chosen carefully. Not only the surgeon but also the assistant must be experienced in microscopic surgery.

Adult↗

PubMed1999

Quantitative assessment of macular thickness in normal subjects and patients with diabetic retinopathy by scanning retinal thickness analyser.

AIMS: To evaluate the scanning retinal thickness analyser (RTA), a novel non-invasive imaging instrument, in diagnosing and quantitatively characterising diabetic macular oedema, and to investigate the relation between central macula thickness measured by RTA and other clinical examinations. METHODS: Central macular thickness was measured using the RTA in 40 normal subjects and 60 patients with diabetic retinopathy. The reproducibility of the retinal thickness measurements was evaluated by calculating the mean of the inter- and intrasession variations. Central macular thickness was correlated with the results of visual acuity measurements, biomicroscopy, and fluorescein angiography. RESULTS: Intra- and intersession reproducibility of the RTA in normal subjects was plus or minus 5.2% (16 microns) and plus or minus 6.1% (19 microns), respectively. The mean central macular thickness was 182 (SD 16) microns in normal subjects, 283 (116) microns in diabetic eyes without clinically significant macular oedema (CSMO), and 564 (168) microns in diabetic eyes with CSMO. Central macular thickness was significantly greater (p < 0.001) in eyes with diabetic retinopathy than in normal subjects, even when macular thickening did not meet the standard for CSMO (p = 0.019) measured by biomicroscopy. Although greater fluorescein leakage at the macula results in greater central macular thickness, only eyes with diffuse leakage had statistically significant macular thickening compared with normal subjects (p = 0.022). Central macular thickness measured with the RTA was significantly correlated with the logarithmic converted visual acuity (r2 = 0.76) in diabetic eyes. CONCLUSION: Scanning RTA, which has good reproducibility, might be useful to quantitatively detect and monitor macular thickening in diabetic retinopathy. Central macular thickness was highly correlated with logarithmic converted visual acuity in diabetic macular oedema.

Adult↗

PubMed1999

Successful treatment of cytomegalovirus colitis with ganciclovir in a patient with adult T cell leukemia lymphoma: case report.

An 84-year-old patient with adult T cell leukemia lymphoma (ATLL) developed diarrhea on day 5 of chemotherapy and was diagnosed with cytomegalovirus (CMV) colitis. Sigmoidoscopy revealed multiple superficial erosions surrounded by a flare. Computed tomography (CT) and ultrasonogram of the abdomen revealed marked thickening of the colonic mucosa. There were 186 CMV antigen-positive leukocytes per 31,000 white blood cells (WBC). A colonic biopsy specimen showed typical CMV nuclear inclusions. Immunohistological study of the specimen was positive for CMV antigen. Administration of ganciclovir (DHPG) 500 mg/day for 14 days improved the diarrhea and other symptoms. On day 30 of the chemotherapy, the patient developed diarrhea again but was diagnosed with pseudomembranous colitis instead of CMV colitis. At that time, CMV antigenemia and a histologic study for CMV were negative. The stool was positive for Clostridium difficile toxin antigen. ATLL patients are believed to be immunocompromised hosts and often develop opportunistic infections such as CMV infection. Most suffer from CMV pneumonia at the end of their course of therapy. Few gastrointestinal (GI) CMV infections are seen in ATLL patients and details of CMV colitis have never been reported. When an ATLL patient develops diarrhea that barely responds to conventional therapy, CMV colitis and pseudomembranous colitis should be listed in the differential diagnosis.

Aged↗

PubMed1999

Exchangeability of accessory Vif and Vpu proteins between various HIV/SIVs (review).

Representative human and simian immunodeficiency viruses (HIV/SIVs) have been monitored for their Vif and Vpu activities in a wide variety of cells. In contrast to the prototype HIV-1, viruses of the other groups do not necessarily have these activities. Only HIV-2 and SIVmnd were clearly demonstrated to show the Vif and Vpu activities, respectively. The exchangeability of these accessory activities between viruses was then assessed to determine the relatedness of the viruses. Quite different from the results for Tat and Rev trans-activators, the activities are almost fully compatible between viruses. These results may facilitate the functional grouping of various HIV/SIVs.

Gene Products, vif↗

PubMed1999

Rev-dependent expression of three species of HIV-1 mRNAs (review).

The expression of structural and accessory genes of human immunodeficiency virus type 1 (HIV-1) except for nef requires a viral regulatory protein Rev. Rev-dependency of the expression of structural (gag, pol and env), regulatory (tat and rev), and accessory genes (vif, vpr, vpu and nef) has been investigated by various systems, and it has been demonstrated that unspliced (encodes gag and pol) and singly-spliced (env-vpu, vif and vpr) viral mRNAs are differentially dependent on the function of Rev. In this review, the function of HIV-1 Rev in relation to these findings is discussed.

Gene Expression Regulation, Viral↗

PubMed1999

Activation of HIV-1 enhancer sequence by vaccinia virus.

To investigate whether vaccinia virus (VV) can augment gene expression of human immunodeficiency virus type 1 (HIV-1), co-transfection experiments were carried out in which recombinant plasmids containing various portions of the HIV-1 long terminal repeat (LTR) linked to the chloramphenicol acetyltransferase (CAT) gene were transfected into cultured cells. A high level of enhancement in CAT activity directed by the HIV-1 LTRs containing the enhancer sequence was observed in cells infected with VV, as in the cells infected with type 1 herpes simplex virus (HSV-1). The sequence responsible for this augmentation of CAT activity was different from that recognized by HIV-1 Tat. These data clearly demonstrated that VV transactivates HIV-1 LTR through a mechanism distinct from that of activation by HIV-1 Tat.

Animals↗

PubMed1999

Cell-dependent functional roles of HIV-1 Nef for virus replication (review).

The stage in the human immunodeficiency virus type 1 (HIV-1) replication cycle that is affected by Nef has been investigated. Nef is dispensable during the transcription to virion production step. In contrast, Nef is critical in the early phase of the virus replication cycle, from virion adsorption to integration. Furthermore, virions produced in the absence of Nef have been demonstrated to be inefficient to complete the virus DNA synthesis. When virions are produced in particular cells without Nef, they exhibit a severe defect in the virus entry process into cells. Taken together, it is concluded that HIV-1 Nef acts via modulation of viral particles to enhance virus infectivity in a cell-dependent manner.

Animals↗

PubMed1999

[A comparative study of visual outcomes following primary vitrectomy and scleral buckling procedures to manage macular off rhegmatogenous retinal detachments].

PURPOSE: To determine the difference between two types of retinal detachment surgery in postoperative visual recovery in the management of macular-off rhegmatogenous retinal detachment. METHODS: We evaluated retrospectively the postoperative visual acuity (VA) in 37 patients who underwent primary vitrectomy (group V) and 39 patients treated with conventional scleral buckling (group S). RESULTS: Although the mean preoperative VA in group V (0.03) was significantly worse (p = 0.04) than that in group S (0.06), there was no statistically significant difference between the groups in postoperative VA throughout the follow-up period. However, in the cases with poor preoperative VA (VA < 0.1), ocular hypotony (IOP < 7 mmHg), or prolonged macular detachment (duration > 7 days), the visual recovery was significantly better (p < 0.05) in group V than in group S from 1 month postoperatively. There were more eyes with a final VA of more than 0.5 in group V than in group S. When considering only the eyes with lenses spared intraoperatively, postoperative cataract progression resulting in secondary visual reduction was statistically significantly greater (p < 0.01) in group V (62%) than in group S (8%). CONCLUSIONS: Primary vitrectomy is effective to attain early visual rehabilitation, especially to manage macula-off retinal detachments with poor preoperative VA, ocular hypotony, and prolonged macular detachment. To prevent a secondary visual reduction, cataract surgery combined with vitrectomy is recommended in selected cases.

Adult↗