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Biomedical subjects

Y Ohta

Publications and source records attributed to Y Ohta.

At least 289 records · Page 16Linked to original sources
PubMed1998

Cytologic and genetic study of polyomavirus-infected or polyomavirus-activated cells in human urine.

OBJECTIVE: To carry out a morphologic and genetic study of human polyomavirus infection or activation in child and adult urine specimens. DESIGN AND SETTING: The study was carried out on 16 urine samples from children with human polyomavirus infection and 104 samples from adults with virus activation identified among 18800 consecutive urine samples (0.64%). RESULTS: All specimens from children showed numerous typical intranuclear inclusion-bearing (INIB) cells. All adult specimens with cytological features similar to childhood specimens were defined as type 1 adult cases. We identified 14 adult cases with marked immunologic suppression as type 1 cases. The inclusions were large, homogeneous, and basophilic, and they were mainly attributable to the BK virus, as demonstrated by a polymerase chain reaction. These infected or activated cells revealed features demonstrating their origin in the superficial transitional epithelium of the urinary tract. Adult cases with different cytologic features were designated as type 2 adult cases. In type 2 adult cases, the number of virus-activated cells was lower, and degenerated intranuclear inclusion-bearing cells with a coarse chromatin pattern were observed in most cases. These characteristics were identified in 90 adults without immunologic suppression. A polymerase chain reaction with BamHI digestion demonstrated JC virus DNA in nearly all of these specimens. CONCLUSION: The JC virus-activated cells found in type 2 adult cases and the BK virus-infected cells found in childhood cases were not of clinical importance. However, the BK virus-activated cells associated with immunologic suppression may have prognostic significance.

Adult↗
PubMed1998

Changes in the gastric vascular network of malignant stroke-prone spontaneously hypertensive rats (M-SHRSP) after administration of the calcium antagonist manidipine.

In malignant SHRSP (M-SHRSP), a strain of stroke-prone spontaneously hypertensive rat (SHRSP), blood pressure rapidly increases during early development (5 weeks of age). Changes in the gastric vascular architecture of WKY and M-SHRSP were investigated using scanning electron microscope images of vascular casts focusing on the morphological differences in the three-dimensional arrangement of the capillaries. In WKY, the density, tortuosity and regular honeycomb formation of the gastric vessels were studied. The casts of gastric capillaries were 5.9 +/- 0.6 microns in diameter with a regular smooth surface. In M-SHRSP, the overall vascular pattern was not regularly organized at 6.3 +/- 1.9 microns in capillary diameter. Administration of the Ca antagonist, manidipine, to 11-week-old M-SHRSP with hypertensive vascular lesions decreased blood pressure and prolonged the rats' survival. With the administration of manidipine, vascular morphological patterns became similar to that of normotensive WKY, and the mean capillary diameter was 8.4 +/- 1.2 microns. It seems that manidipine plays a role in the recovery of normal vascular structure, as well as decreasing blood pressure.

Animals↗
PubMed1998

Changes in nitric oxide production with lesion development in the gastric mucosa of rats with water immersion restraint stress.

In rats with gastric mucosal lesions induced by water immersion restraint (WIR) stress over a 6 h period, increases in the serum and gastric mucosal concentrations of nitrite/nitrate, the breakdown products of NO, occurred with a drastic increase in inducible NO synthase (iNOS) activity in the gastric mucosa. Pretreatment with aminoguanidine (100 mg/kg), a relatively selective iNOS inhibitor, attenuated not only gastric mucosal lesion development, but also increases in serum and gastric mucosal nitrite/nitrate concentrations with inhibition of increased gastric mucosal iNOS activity in rats with 6 h of WIR stress. A good positive correlation between either serum or gastric mucosal nitrite/nitrate concentration and gastric mucosal iNOS activity in all rats used (r = 0.741 or 0.842, respectively, p < 0.001) was found. These results suggest that in WIR-stressed rats, an increase in NO production via iNOS in the gastric mucosa could contribute to gastric mucosal lesion development.

Animals↗
PubMed1998

[Results of resection of T3N0-2M0 non-small cell lung cancer according to involved organ and nodal status].

The purpose of this study was to evaluate the results of surgical treatment of T3N0-2M0 non-small cell lung cancer according to involved organ and nodal status. Between 1973 and July 1997, 157 patients with T3 non-small cell lung cancer were surgically treated in our department. Five-year survival was 23% for all cases, 35% for patients with curative resection, and 0% for patients with non-curative resection (p < 0.001). Five-year survival rate of patients with T3N0, T3N1, and T3N2 was 37%, 39%, and 3%, respectively (T3N0 vs T3N2, T3N1 vs T3N2, p < 0.01). According to the depth of chest wall involvement of T3N0 tumor, 5-year survival rate was 50% in the patients with the involvement of parietal pleura, 39% in the patients with the involvement of intercostal muscle, and 15% in the patients with the involvement of rib or more (parietal pleura vs rib or more, p < 0.05). In T3N0 patients with the involvement of only parietal pleura, the 5-year survival rate of parietal pleurectomy and en bloc chest wall resection was 43% and 46%, respectively (N.S.). Five-year survival rate of T3N1 patients with invasion in main stem bronchus was 46% and 3 of 5 patients of T3N0-1 tumor with pericardial invasion survived more than 5 years. From these results, T3N0 tumor involving chest wall without rib invasion, and T3N0-1 tumor involving main bronchus and pericardium are expected good survival. However, the prognosis of the patients with coexistent N2 disease or with incomplete resection remains poor in regardless with the type of involved organ. To correctly evaluate the surgical results of other types of T3 tumor, it is required to collect more cases or to perform multicenteric study.

Adult↗
PubMed1998

[Anesthesia for fourteen cases of auto-renal transplantation].

We experienced anesthetic management of 14 cases of auto-renal transplantation. The causative diseases are stenosis (n = 7) and aneurysm of the renal artery (n = 5) as well as renal cancer (n = 2). The mean time intervals for operation, anesthesia, and clamping of the renal artery were 10 h 54 min, 12 h 42 min and 4 h 14 min, respectively. In the patients whose serum creatinine values were above 1 mg.dl-1 within the 3rd postoperative day, time intervals for operation and anesthesia were significantly longer than in the patients whose serum creatinine values remained below 1 mg.dl-1. The water balance in the former patients was significantly positive in comparison with the latter patients. The auto-renal transplantation is a highly invasive surgery so that proper fluid management and sufficient urination seem to be especially important for the perioperative management of patients of this category.

Adult↗
PubMed1998

Contribution of airway resistance to airway pressure during mechanical ventilation: an experimental study.

Although airway resistance (R) is an important parameter of the pulmonary condition, its determination during mechanical ventilation is not easy. Most physicians estimate R from peak airway pressure during mechanical ventilation. We assessed the relationship between R and peak airway pressure by a computer simulation. The time course of airway pressure (Ptr) during mechanical ventilation was calculated from the airway pressure at end-inspiration and respiratory flow, allowing for the buffering effect of the dead space. The parameters for computer simulation were obtained from 5 paralyzed and mechanically ventilated dogs. The predicted Ptr curve was a function of airway resistance. Since R was not directly determined by the animal experiments, we determined R by using the Ptr curve most closely approximating the original Ptr curve as the true R. The R-peak tracheal pressure relationship predicted by computer simulation showed that the peak airway pressure increased almost linearly with increases in R. However, in computer simulation, when R was increased 10-fold from the value at airway relaxation, the peak airway pressure increased only 6-fold from the corresponding value. We conclude that peak airway pressure is a relatively insensitive parameter for the estimation of airway constriction during mechanical ventilation.

Airway Resistance↗
PubMed1998

Anti-streptococcal activity of homologous polymorphonuclear neutrophils from patients with surgically treated oral infections.

The phagocytic bactericidal activity of homologous polymorphonuclear neutrophils (PMN), obtained from patients with severe, moderate and mild oral infections with Streptococci, was investigated. The drop in viable bacterial cell counts in PMNs from 3 patients with a severe infection, after 4 hours of incubation, was much greater than in PMNs from moderate or mild infections. We conclude that the phagocytic bactericidal activity of PMNs is stronger in patients suffering from severe oral infections with Streptococci.

Adult↗
PubMed1997

Identification of class I genes in cartilaginous fish, the most ancient group of vertebrates displaying an adaptive immune response.

Sharks are members of the most primitive class of vertebrates (Chondrichthyes) shown to have an adaptive immune system. Suprisingly, however, class I genes have not been identified unambiguously in this taxon, and absence of class I loci or a failure to express class I genes might explain some of the relatively "weak" adaptive immune responses documented in cartilaginous fish. We report here the isolation of three unique cDNA clones from two different species of sharks that encode bona fide class I proteins. These clones exhibit different sequence and expression profiles indicating that they are likely to represent both classical and nonclassical class I lineages. In addition, our preliminary analysis suggests that there may be transfer of gene segments among shark class I genes over evolutionary time. The cloning of shark class I genes completes the identification of molecules that define the adaptive immune system (including Ig, TCR, and MHC class II proteins) in this taxon. Thus, simple models invoking a total absence of certain molecular hallmarks of the immune system to account for poor immune responsiveness in cartilaginous fish should be abandoned.

Amino Acid Sequence↗
PubMed1997

Awareness of donor alloantigens in antiadhesion therapy induces antigen-specific unresponsiveness to islet allografts.

BACKGROUND: Antiadhesion therapy using monoclonal antibodies (mAbs) to adhesion molecules in vivo has been shown to produce significant prolongation of graft survival in various transplantation models. However, it remains unclear whether antiadhesion therapy operates by merely blocking adhesion between antigen-presenting cells and T cells physically and/or by blocking costimulatory signals while preserving signals mediated through T-cell receptors in vivo. We examined antigen-specific T-cell responses during and after antiadhesion therapy. METHODS: BALB/c islets were transplanted into the renal subcapsular space of streptozotocin-induced diabetic C57BL/6 mice given anti-lymphocyte function-associated antigen (LFA)-1 and/or anti-intercellular adhesion molecule-1 mAb treatment. The animals bearing surviving islet allografts were challenged with BALB/c or third-party islets on day 7 or more than 100 days after transplantation. RESULTS: Islet allografts were acutely rejected in untreated animals, with a mean survival time (MST) of 19+/-8 days. Administration of anti-LFA-1 mAb induced significant prolongation of graft survival with a mean survival time of 72+/-33 days, and half of the allografts showed indefinite survival. The animals given anti-LFA-1 mAb alone 7 days before transplantation showed acute rejection of BALB/c islets, whereas a significant number of animals given anti-LFA-1 mAb and the BALB/c islet allograft simultaneously accepted secondary BALB/c islets, but rejected third-party islets. Likewise, most of the animals bearing long-term functioning BALB/c allografts for more than 100 days accepted secondary BALB/c islets, but rejected C3H islets acutely. Interestingly, the spleen cells from these animals transferred unresponsiveness to BALB/c islets into the 2.5-Gy x-irradiated recipients, whereas those from naive animals induced acute rejection. CONCLUSIONS: These results indicate that anti-LFA-1 mAb treatment prevents T-cell activation leading to rejection, but results in a T-cell receptor engagement leading to antigen-specific unresponsiveness maintained by transferrable suppressor cells.

Animals↗
PubMed1997

Marked improvement of PAC and BAC cloning is achieved using electroelution of pulsed-field gel-separated partial digests of genomic DNA.

We describe a simple electroelution method for purifying large, gel-fractionated DNA molecules that alleviates the need for melting of the agarose and subsequent enzymatic agarose digestion. The method yields DNA that is visibly more intact than that purified from a standard agarose-digestion protocol and is more amenable to large-fragment cloning with PAC and BAC vectors. These findings are notable in that PAC and BAC library construction is a very labor-intensive and costly procedure, such that any net improvement in cloning efficiency is highly advantageous. This method also should prove useful towards other applications which require purification of very large DNA molecules, such as YAC cloning.

Animals↗
PubMed1997

Identification of S100b protein as copper-binding protein and its suppression of copper-induced cell damage.

We have isolated from bovine brain a protein with a high capacity to inhibit the copper ion-catalyzed oxidation of L-ascorbate and identified it as S100b protein, an EF-hand calcium-binding protein, by sequencing its proteolytic peptides. Copper binding studies showed that this protein has four copper-binding sites per dimeric protein molecule with a dissociation constant of 0.46 microM and that in the presence of L-ascorbate, copper ions bind to a total of six binding sites with a great increase in affinity. Furthermore, we examined whether S100b protein can prevent copper-induced cell damage. Bovine S100b protein was found to suppress dose-dependently the hemolysis of mouse erythrocytes induced by CuCl2. We transformed Escherichia coli cells with pGEX-5X-3 vector containing a cDNA for rat S100b protein, so that this protein could be expressed as a fusion protein with glutathione S-transferase. The transformed cells were demonstrated to be markedly resistant to a treatment with CuCl2 plus H2O2 as compared with the control cells expressing glutathione S-transferase alone. These results indicate that S100b protein does suppress oxidative cell damage by sequestering copper ions.

Amino Acid Sequence↗
PubMed1997

Glycine facilitates gamma-glutamylcysteinylethyl ester-mediated increase in liver glutathione level.

gamma-Glutamylcysteinylethyl ester (gamma-GCE) increases reduced glutathione (GSH) levels in GSH-depleted rat hepatocytes. Because glycine, a constituent of GSH, exists at 0.3 to 0.4 mM in rat plasma, we examined the influence of glycine added to the medium on the action of gamma-GCE to increase GSH levels in the rat hepatocytes. Glycine (0.2-0.8 mM) dose-dependently enhanced gamma-GCE-mediated increase in intracellular GSH levels with an increase in intracellular gamma-GCE levels. These results indicate that exogenous glycine facilitates gamma-GCE-mediated increase in intracellular GSH levels in rat hepatocytes possibly by enhancing the uptake of gamma-GCE into the cells.

Animals↗
PubMed1997

Role of gastric mucosal constitutive and inducible nitric oxide synthases in the development of stress-induced gastric mucosal lesions in rats.

Changes in gastric mucosal constitutive NO synthase (cNOS) and inducible NO synthase (iNOS) activities with the development of gastric mucosal lesions induced by water immersion restraint (WIR) stress were investigated in rats pretreated with and without NOS inhibitors. A decrease in cNOS activity and an increase in iNOS activity in the gastric mucosa occurred with gastric mucosal lesion development. Pretreatment with N(G)-monomethyl L-arginine, a non-selective NOS inhibitor, enhanced gastric mucosal lesion development with inhibition of gastric mucosal cNOS and iNOS activities, although the inhibited iNOS activity was still higher than the normal level. Pretreatment with aminoguanidine, a selective iNOS inhibitor, prevented gastric mucosal lesion development with inhibition of iNOS activity and maintenance of cNOS activity in the gastric mucosa. These results indicate that in WIR-stressed rats, an increase in iNOS activity and a decrease in cNOS activity in the gastric mucosa are closely related to the development of gastric mucosal lesions.

Animals↗
PubMed1997

Actin-binding protein-280 binds the stress-activated protein kinase (SAPK) activator SEK-1 and is required for tumor necrosis factor-alpha activation of SAPK in melanoma cells.

SEK-1, a dual specificity protein kinase that serves as one of the immediate upstream activators of the stress-activated protein kinases (SAPKs), associates specifically with the actin-binding protein, ABP-280, in vitro and in situ. SEK-1 binds to the carboxyl-terminal rod segment of ABP-280, upstream of the ABP carboxyl-terminal dimerization domain. Activation of SEK-1 in situ increases the SEK-1 activity bound to ABP-280 without changing the amount of SEK-1 polypeptide bound. The influence of ABP-280 on SAPK regulation was evaluated in human melanoma cells that lack ABP-280 expression, and in stable transformants of these cells expressing wild type ABP, or an actin-binding but dimerization-deficient mutant ABP (ABPDeltaCT109). ABP-280-deficient cells show an activation of SAPK in response to most stimuli that is comparable to that seen in ABP-280-replete cells; ABP-280-deficient cells, however, fail to show the brisk tumor necrosis factor-alpha (TNF-alpha) activation of SAPK seen in ABP-replete cells and have an 80% reduction in SAPK activation by lysophosphatidic acid. Expression of the dimerization-deficient mutant ABP-280 fails to correct the defective SAPK response to lysophosphatidic acid, but essentially normalizes the TNF-alpha activation of SAPK. Thus, a lack of ABP-280 in melanoma cells causes a defect in the regulation of SAPK that is selective for TNF-alpha and is attributable to the lack of ABP-280 polypeptide itself rather than to the disordered actin cytoskeleton that results therefrom. ABP-280 participates in TNF-alpha signal transduction to SAPKs, in part through the binding of SEK-1.

Actins↗
PubMed1997

Apoptotic cell death during the estrous cycle in the rat uterus and vagina.

BACKGROUND: Rodent uterus and vagina show marked histological changes during the estrous cycle. Apoptotic cell death has been demonstrated in hamster and rat uterine epithelium during the estrous cycle by electron microscopy: numerous epithelial cells undergo apoptosis at estrus. We examined cell death and cell proliferation in rat uterus and vagina during estrous cycle. METHODS: To examine the rate of proliferation in uterine and vaginal cells at each estrous stage, the numbers of cells at metaphase were counted separately in epithelial and stromal cells. We identified the apoptotic cells in uterus and vagina at each estrous stage by using DNA fragmentation, in situ DNA 3'-end labeling, and electron microscopy. RESULTS: Mitotic rates in uterine luminal and glandular epithelial cells were low at metestrus and estrus, respectively. Intense fragmentation was found in the uterus at metestrus and in the vagina at proestrus and metestrus. In uterine luminal and glandular epithelial cells, apoptotic index showed peaks at metestrus and estrus, respectively. In vaginal epithelial cells, many apoptotic cells were encountered in the superficial layer at proestrus, which may contribute to keratinization. In the middle and basal layer of vaginal epithelial cells, apoptotic index was high at metestrus, when mitotic rate was low. Electron microscopy confirmed the results of the labeling studies. CONCLUSIONS: Apoptotic cell death was encountered in the uterus and vagina during estrous cycle in rats. There is an inverse correlation between cell death and cell proliferation in rat uterine and vaginal epithelial cells during the estrous cycle.

Animals↗
PubMed1997

Treatment of bronchial stricture due to endobronchial tuberculosis.

Between 1974 and 1995 we encountered 19 cases of bronchial stricture or obliteration caused by endobronchial tuberculous lesions. In 11 the involvements were located at the right bronchus (including involvements of segmental and middle lobe bronchi) and in 8 at the left bronchus. On bronchoscopic biopsy of the stenosed bronchus, 7 patients showed histopathologic findings of tuberculous bronchitis, but 12 patients showed nonspecific inflammatory granular tissue. Five patients were kept under conservative observation because of mild subjective symptoms or refusal to undergo operation. Two patients underwent stent procedures but had poor outcomes. Twelve patients underwent operation. As the bronchial lesions in four of them were confined to the lobar or segmental bronchus, lobectomy was performed. One patient with a history of infantile tuberculosis had developed complete obliteration of the left main bronchus and cystic bronchiectasis in the entire lung parenchyma; pneumonectomy was essential. Seven patients who had strictures involving the main bronchus underwent bronchoplastic surgery with right (n = 4) or left (n = 3) upper sleeve lobectomy. None of the patients treated surgically showed any postoperative complication or recurrence of the tuberculosis. These surgical results for endobronchial tuberculosis indicate the need for early detection and operation. Bronchoscopy and computed tomography are the methods of choice for accurate diagnosis of bronchial involvement and assessment of the surgical indications. It is emphasized that bronchoplastic surgery is the best treatment for bronchial stricture involving bilateral main bronchi.

Adult↗
PubMed1997

Endoscopic hydrostatic balloon dilation of ulcer-induced pyloric stenosis in rheumatoid arthritis and secondary amyloidosis.

We describe a 50-year-old Japanese woman with rheumatoid arthritis who presented with near-complete gastric outlet obstruction. The patient also suffered from secondary gastrointestinal and cardiac amyloidosis. Gastroscopy revealed multiple huge gastric antral ulcers in which amyloid deposits were identified on histologic examination. The ulcers became scars after treatment with omeprazole, which cause in severe pyloric stenosis. Endoscopic hydrostatic balloon dilation under fluoroscopic guidance was performed twice for 10 min. The pyloric outlet remained sufficiently patent 22 months later.

Amyloidosis↗