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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 361 records · Page 20Linked to original sources
PubMed1995

Alteration of baroreceptor and chemoreceptor reflexes in spontaneously hypertensive rats.

1. Electrical stimulation of the aortic depressor nerve elicited depressor and bradycardiac responses in both spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY) rats, but in spontaneously breathing animals responses were weaker in SHR than in WKY. 2. Responses did not significantly differ in artificially ventilated animals except that high stimulation intensity elicited significantly greater bradycardiac responses in WKY. A decrease in ventilatory rate occurred in both strains. 3. Electrical stimulation of the carotid sinus nerve (CSN) elicited an initial pressor response followed by a depressor response with a minimal change in heart rate in either strain. The pressor response in SHR was greater than in WKY. Depressor responses in SHR were weaker than those in WKY with or without artificial ventilation. CSN stimulation increased ventilatory rate in both strains but the frequency-related responses differed at higher stimulation intensity. 4. These results suggest that there are alterations in the function of central or afferent components of chemoreceptor and baroreceptor reflexes in SHR in addition to previously described structural changes at the level of peripheral sensory receptors.

Animals↗
PubMed1995

Baroreceptors in the carotid sinus contribute to arterial baroreceptor reflexes in normotensive rats.

1. Baroreceptor reflex influences on renal sympathetic nerve activity (RSNA) were estimated with non-linear regression analysis (sigmoidal curve fitting) before and after transection of carotid sinus nerves (CSN) and aortic depressor nerves (ADN) in rats. 2. Transection of ADN reduced the gain of the reflex to 42% of basal levels with increases in arterial pressure (MAP) and RSNA. Subsequent transection of CSN eliminated the remaining sigmoidal correlation between MAP and RSNA without further changes in resting MAP and RSNA. 3. By comparison, the transection of CSN reduced the gain of the reflex to 53% of basal levels without affecting other variables. Additional transection of both ADN eliminated the remaining sigmoidal correlation between MAP and RSNA with further increases in resting MAP and RSNA. 4. These results indicate that carotid sinus baroreceptors exist in rats. They contribute to baroreceptor-mediated reflex changes in RSNA as do aortic baroreceptors, although the working range of MAP may increase with transection of the latter.

Animals↗
PubMed1995

Transient P300 abnormality of event-related potentials following unilateral temporal lobectomy.

Event-related potentials (ERP) were recorded during auditory oddball tasks for a patient prior to and soon after left anterior temporal lobectomy. The N100 amplitude decreased bilaterally although the latency did not change after the lobectomy. The P300 amplitude decreased in the left hemisphere at 1 and 2 weeks after surgery, then recovered to the pre-operative level at 4 weeks. These findings suggest that the medial temporal structure participates in the generating system of P300.

Adult↗
PubMed1995

Immunocytochemical study of microvilli in a gastric carcinoma-derived cell line.

To study the structural components of microvilli of the KATO-III cell, we used anti-villin, -ezrin, and anti-MVM (microvillous membrane prepared against mouse intestinal microvilli) antibodies. Villin and ezrin cross-link actin bundles of microvilli such as those in the small intestine and renal proximal cells. Electromicroscopically, the cytoskeletal core of microvilli of the KATO-III cell was constituted of actin-filament bundles. The anti-villin antibody but not anti-ezrin antibody reacted with the KATO-III cell as demonstrated by FITC-immunofluorescence and PAP-staining. Anti-villin, anti-MVM, but not anti-ezrin antibody, reacted with the KATO-III cell surface and with intracellular materials. Western blot analysis using anti-villin and anti-MVM antibodies revealed proteins of approximately 95 kDa (villin), and 15 kDa in the microsomal membrane fractions of KATO-III cells, respectively. Immunocytochemical and confocal laser microscopic studies showed that the cell-surface and the intracellular microcysts of KATO-III cells were preferentially decorated by anti-villin and anti-MVM antibodies. These data suggested that some actin-binding proteins, such as villin, were localized at the cell surface and on some of the intracellular cytoplasmic structures of the KATO-III cell.

Animals↗
PubMed1995

Efficacy of subcutaneous application of live infectious bursal disease vaccine in young chickens with maternally derived antibody.

The infectivity of neutralized IBDV by normal chicken serum (NCS) was detected in day-old and 3-week-old chicken spleen adherent (CSA) cells, and that of neutralized IBDV by maternal antibody (MN-Ab) was detected in 3-week-old CSA cells. Moreover, CSA cells from day-old chickens had complement receptor (CR), and CSA cells from 1-week-old had both CR and Fc receptor (FcR). However, the infectivity of neutralized IBDV by MN-Ab was confirmed on CSA cells which were blocked for FcR on CSA cells by heat-aggregated NCS (56 degrees C, 60 min). These results indicated that infection of neutralized IBDV by NCS on CSA cells occurred via CR, and neutralized IBDV by MN-Ab was infected via FcR. In day-old specific pathogen free (SPF) chickens, the antibody level in NCS treated and non-treated IBD live vaccine subcutaneously inoculated groups was higher than the levels in the MN-Ab-treated IBDV inoculated group, and detected until 28 days old. Moreover, subcutaneously inoculated chickens were protected against the challenge of wild IBDV at 21 days old, whereas subcutaneously inoculated chickens were infected with MN-Ab-treated IBD live vaccine. In commercial layers which had MN-Ab, antibody levels of subcutaneously vaccinated group were higher than both the non-vaccinated and orally vaccinated groups, and virus isolation and viral antigen were positive with high detection rates on peripheral lymphocytes of each subcutaneously vaccinated group of SPF and commercial chickens.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

[Evaluation of early colorectal cancer with submucosal invasion based on histological architecture].

To clarify the clinicopathological features of tumors with submucosal invasion, especially superficial elevated and sessile ones, histological architectures of 32 cases of submucosal invasive cancers were analyzed. They were classified into 3 types based on cross-section view: PG and NPG of Shimoda's classification and PG'. Histological architectures were drawn in accordance with these findings. In 7 PG-Ca which consisted of PG only, no apparent correlation was found between the tumor sizes and invasion depth of submucosal layer. However, 12 NPG-Ca which consisted of NPG only and 12 Mixed-Ca which include various cross-section views both showed massive invasion into the submucosa with 1 cm or more in tumor size. Therefore these two types were similar in biological behavior in terms of invasion depth. And degree of submucosal invasion tended to increase in the order of PG-Ca, Mixed-Ca and NPG-Ca. Examinating histological architectures of the Mixed-Ca tumors in details, all of these cancers were consisted of both PG and PG'. Of the 12 Mixed-Ca, 91.7% were proved to be PG dominant type. Macroscopically, I s and II a contained 88.9% and 40.0% of Mixed-Ca, respectively. In conclusion, these results suggest that PG' is a subtype of PG, and PG-Ca have a correlation between tumor invasion and alteration from PG to PG' in histological architectures among submucosal cancers. It is important to clarify morphological features of PG' in margin of I s and II a tumors in diagnosing the depth of early colorectal cancers.

Colon↗
PubMed1995

CT-defined large subcortical infarcts: correlation of location with site of cerebrovascular occlusive disease.

PURPOSE: To correlate the location of large subcortical infarcts with the site of cerebrovascular occlusive disease. METHODS: We examined CT and angiographic findings of 38 patients with major arterial occlusive disease and newly developed large subcortical infarcts of 2.0 cm or more, which were classified into three types: striatocapsular infarcts in the basal ganglia, terminal supply area infarcts in the corona radiata, and terminal supply area infarcts in the centrum semiovale. RESULTS: Two or three of the types of infarct were sometimes combined; the combination of the striatocapsular and corona radiata infarcts was the most frequent (14 [36.8%] of 38). Thirty-four (89.5%) had atherosclerotic major arterial occlusive diseases; 22 (57.9%) had occlusive diseases of the internal carotid artery, and 12 (31.6%) had diseases of the middle cerebral artery. The other 4 (10.5%) had embolic transient middle cerebral artery occlusion. Middle cerebral artery occlusive diseases frequently produced striatocapsular (13 [81.3%] of 16) and corona radiata (13 [81.3%] of 16) infarcts but never induced the centrum semiovale lesions. On the other hand, in patients with internal carotid artery occlusive disease, the centrum semiovale (16 [72.7%] of 22) was more susceptible to ischemia than the striatocapsular region (11 [50%] of 22) or the corona radiata (9 [40.9%] of 22). CONCLUSIONS: Middle cerebral artery occlusive diseases frequently produced striatocapsular and/or corona radiata infarcts but never induced the centrum semiovale lesions, which were usually associated with internal carotid artery occlusive diseases.

Adult↗
PubMed1995

Endoscopic therapy for early gastric cancer. Utility of endosonography and evaluation of prognosis.

We analyzed 30 endoscopically treated patients with early gastric cancer in terms of the utility of endoscopic ultrasonography (EUS) and the evaluation of prognosis. Endoscopic therapy for early gastric cancer included strip biopsy, laser irradiation, and OK-432 injection. Examination of the depth of cancer invasion in the strip biopsy specimens showed that the diagnostic accuracy of EUS was 85.7%. Complete resection rate in strip biopsy was 82.8%, and the patients with incompletely resected cancer were successfully treated with laser irradiation and/or OK432 injection. The prognosis of the patients treated with strip biopsy was good. Three patients died of causes other than gastric cancer. Local recurrence and a heterochronous new lesion developed in six patients, but all of these cases were successfully treated with additional strip biopsy. All but one patient treated with laser irradiation and/or OK 432 injection survived during the study period. These results suggest that EUS is useful in determining the indication of endoscopic therapies and that prognosis is good in patients with early gastric cancer treated endoscopically.

Aged↗
PubMed1995

[Pharmacological and biochemical investigation of intracavital fluorinated pyrimidine chemotherapy].

We investigated the biochemical and molecular pharmacological parameters of fluorinated pyrimidines using malignant cells in pleural effusion or ascites from patients with malignant disease both before and after fluorinated pyrimidine chemotherapy, either systemically or intravesically. In four out of fifteen cancer patients, we could analyze the alteration of thymidylate synthase (TS) catalytic activity both before and after the treatment, showing that there was a decrease ranging 28% through 96.9%. We also analyzed a level of TS messenger RNA and TS protein using molecular biotechniques. None of these mutual correlations has so far been demonstrated, indicating that the data were analyzed through samples from patients not responding to the fluorinated pyrimidines. In a responding patient with advanced breast cancer, pre-treatment total TS protein was 130 fmol/mg and the TS activity was 3.27 pmol/mg/min. After intrapleural instillation of a combination of 5-FU 250 mg and leucovorin 3 mg, the total amount and the catalytic activity of TS could be measured. On the 11th day of treatment, the TS protein level decreased to 26 fmol/mg and the TS catalytic activity also decreased to 0.1 pmol/mg/min resulting in a TS inhibition rate of 92.3 percent. On the 17th day, the patient's malignant pleural effusion disappeared almost completely, suggesting that substantial TS inhibition may reflect the clinical evidence. This particular data showed that it would be predictable for clinical outcome to evaluate these parameters before and after fluorinated pyrimidine chemotherapy. Further study is warranted to evaluate the exact role of analyzing these parameters in clinical practice.

Aged↗
PubMed1995

[Isoenzyme as tumor marker].

Expression of cancerous isoenzymes in various malignant tumors has been extensively studied using different biochemical techniques. Cancerous alkaline phosphatase (ALP) isoenzymes such as variant ALP and placental ALP are apparently detected in sera or tissues from patients with malignant tumors. Variant ALP is a specific tumor marker for hepatocellular carcinoma (HCC). Placental ALP is found in sera of patients with various malignant diseases. However, the positive rate of each ALP isoenzyme is low except for high positivity of placental ALP in seminoma. Novel gamma-glutamyltranspeptidase (gamma-GTP) isoenzyme is specifically found in about 60% of sera from patients with HCC, but in only 3% of patients with benign liver diseases, suggesting high specificity for HCC. Serum prostatic acid phosphatase (PAT), which increases in activity in parallel with the growth of prostatic tissue, is an useful marker for prostatic cancer. Thus, several cancerous isoenzymes are available for diagnosis of various malignant tumors.

Biomarkers, Tumor↗
PubMed1995

[The development of serum alkaline phosphatase and gamma-glutamyl transpeptidase in early stages of primary biliary cirrhosis].

We carried out a retrospective study for the development of biochemical abnormalities in nine patients with early stages of primary biliary cirrhosis (PBC). All patients had elevated serum alkaline phosphatase (ALP) and gamma-glutamyl transpeptidase (gamma-GTP) levels when the diagnosis of PBC was obtained. In all cases, serum gamma-GTP levels initially increased, followed by the elevation of ALP. In the routine laboratory tests gamma-GTP is more sensitive than ALP for the screening for early PBC.

Aged↗
PubMed1995

Low incidence of acute GVHD in patients transplanted with marrow from HLA-A,B,DR-compatible unrelated donors among Japanese.

To prevent GVHD in BMT from unrelated donors, the matching of HLA between patient and donor is crucial. The appearance of acute GVHD was studied in 51 patients with hematological malignancies who were transplanted with non-T cell purged marrow from HLA-A,B and DR compatible unrelated donors with the assistance of the Tokai Marrow Donor Bank of Nagoya, Japan. Probability of grade II-IV acute GVHD was 32.0% and of grade III-IV acute GVHD was 17.0%. HLA-class II antigen compatibility showed a good correlation with the occurrence of acute GVHD. When the percentage relative response (RR) of MLC between patient and donor (GVHD vector) was < or = 5, grade II-IV acute GVHD was found in only 7.7% of patients (n = 16) and no severe grade III-IV GVHD occurred. Among patients with 6-10% RR (n = 10), 25.9% showed grade II-IV GVHD and 14.3% grade III-IV GVHD. Among patients with > or = 11% RR (n = 20), however, the incidence of grade II-IV acute GVHD reached 51.8% and that of grade III-IV acute GVHD 36.2%. These reactivities of MLC reflected the compatibility of HLA-DRB1 and DPB1. The fact that the incidence of acute GVHD in BMTs from HLA-A,B,DR compatible Japanese pairs was found to be lower than in the USA may be due to less diversity of the genetic background in Japan.

Adolescent↗
PubMed1995

[Post operative mediastinitis: the experience of two cases after graft replacement of the ascending aorta].

A mediastinitis after a graft replacement of the ascending aorta is serious complication and sometimes could be lethal. We have experienced two cases of such a condition, recently. In both cases, the debridement of the mediastinum and omental transposition were performed. Case 1 had a recurrent mediastinitis due to residual dead space infection, but was cured by a percutaneous drainage and a continuous irrigation. In case 2, the omentum was carefully positioned to occupy the dead space around the graft, because of the experience of the first case and gave a good result. We believe that omental transposition is an effective treatment for the postoperative mediastinitis.

Adult↗
PubMed1994

A possible role of sphingosine in induction of apoptosis by tumor necrosis factor-alpha in human neutrophils.

Treatment of human neutrophils with tumor necrosis factor-alpha (TNF-alpha) resulted in an increase in concentration of ceramide and its catabolite, sphingosine. Sphingosine, a potent endogenous protein kinase C (PKC) inhibitor, as well as TNF-alpha, induced internucleosomal DNA fragmentation and morphological changes characteristic of apoptotic cells. Ceramide and sphingosine-1-phosphate, the initial product of sphingosine catabolism, did not cause apoptosis under our experimental conditions. In addition, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7) and N,N-dimethylsphingosine (DMS), known as PKC inhibitors, also induced apoptosis, suggesting that induction of apoptosis by sphingosine may be related to inhibition of PKC activity. These results indicate that sphingosine deacylated from ceramide may be an endogenous modulator mediating apoptotic signals by TNF-alpha in neutrophils.

Apoptosis↗
PubMed1994

Quantification of free sphingosine in cultured cells by acylation with radioactive acetic anhydride.

A simple and sensitive method for quantification of sphingosine in cellular lipid extracts was developed. The assay is based on quantitative conversion of sphingosine to N-[3H]acetylated sphingosine ([3H]C2-ceramide) by N-acylation with [3H]acetic anhydride under certain conditions. Sphingosine was extracted from cultured cells with chloroform and methanol and then treated with base to remove interfering glycerolipids having reactive amino groups (e.g., phosphatidylethanolamine or phosphatidylserine). Sphingosine was acylated with [3H]acetic anhydride in the presence of 0.004 N NaOH. Acylation was complete in 1 h at 37 degrees C when sphingosine was present in the picomole range. After the acylation, samples were treated with NaOH to reduce background radioactivity by removing the remaining [3H]acetic anhydride and hydrolyzing any ester linkages formed during the acylation and resolved by thin-layer chromatography. [3H]C2-ceramide converted from sphingosine with the acylation was detected with radioautography and quantitated by scraping the corresponding band and counting its radioactivity with a scintillation counter. [3H]C2-ceramide formed was quantitatively measured. This assay allows quantification of sphingosine over a range of 10 to 1500 pmol. The amount of sphingosine in lipid extracts from cultured cells was proportional to the number of cells. Sphingosine levels in human gastric cancer KATO III cells, human promyelocytic leukemic HL60 cells, and human monoblastic U937 cells, determined by this method, were 26.6 +/- 2.2, 6.3 +/- 0.4, and 6.8 +/- 0.6 pmol per 10(6) cells, respectively. Our new procedure allows quantification of sphingosine levels present in the low picomole range in lipid extracts from biological samples.

Acetic Anhydrides↗