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Biomedical subjects

N Ohta

Publications and source records attributed to N Ohta.

At least 217 records · Page 12Linked to original sources
PubMed1990

Neuraminic acid and related compounds. V. Syntheses of biologically active sialosyl-glycerol derivatives and galactosyl-glycerol derivative.

New 1-acyl-sialosyl-glycerol derivatives (1a--d alpha, 1a--d beta, 2 alpha, 2 beta, which mimic the structure of the capsular polysaccharide of group C meningococcal were synthesized by the use of a chiral glycerol derivative, and were found to have phospholipases A2 and C inhibitory activities. Furthermore, synthesis of 2-palmitoyl-sialosyl-glycerol derivative (4 alpha, 4 beta, 5 alpha, 5 beta), galactosyl-glycerol derivative (6), and sialosyl-galactosyl-glycerol derivative (7) were carried out to examine the difference between these activities. Among these sialosyl derivatives, 3-palmitoyl-sialosyl-glycerol derivatives (1--3 alpha, 1--3 beta) demonstrated the most potent inhibitory activities.

Galactosides↗
PubMed1990

[Tracheobroncho plasty: anastomotic technique with encircled placement of sutures].

Tracheobroncho plasty is currently carried out by a number of surgical techniques. Extraordinal plastic modes require special techniques. We prefer to anastomose the posterior site by tying sutures respectively, but at the anterior site by tying sutures after placing them. However, this procedure is difficult to apply in extraordinal plastic modes. Our preference in such cases is to place all anastomotic sutures clipped to field drapes, and then tie them down from front to back of the anastomotic site. This anastomotic technique was carried out in cases of 1) extreme tension in approximation of both anastomotic stumps, 2) subaortic arch anastomosis, and 3) end to side anastomosis. This technique prevents cutting with a suture through cartilage rings with a suture and enables anastomosis to be carried out even in the deep and narrow operative field. The usefulness of this technique was discussed.

Anastomosis, Surgical↗
PubMed1990

Functional characterization of lymphocyte response to fractionated house dust mite antigens (Dermatophagoides pteronyssinus) in atopic and non-atopic individuals.

This study investigated the cellular response of human lymphocytes to Dermatophagoides pteronyssinus crude antigen and 14 molecular weight (MW) fractions. The cells were derived from atopic patients and healthy individuals who were skin test-positive or skin test-negative to mite antigen. When stimulated with crude antigen, the group of patients showed elevated proliferation and production of lymphokine in comparison with the healthy skin test-negative individuals (P less than 0.01). By stimulation with fractions, there was a remarkable variety in the responding patterns to each fraction. However, when expressed as a mean value, the patient group exhibited a sharp and high peak at 95,000 MW, which is different from IgE responses. In the other two groups, no apparent peak response was observed. Lymphokine production by fraction stimulation was studied in six distinct individuals. The most important fractions for inducing lymphokine production differed in each individual tested. Moreover, fractions which induced active lymphokine production were not necessarily the main targets of proliferative response in atopic patients.

Allergens↗
PubMed1989

Genetic switching in the flagellar gene hierarchy of Caulobacter requires negative as well as positive regulation of transcription.

Caulobacter crescentus flagellar (fla, flb, or flg) genes are periodically expressed in the cell cycle and they are organized in a regulatory hierarchy. We have analyzed the genetic interactions required for fla gene expression by determining the effect of mutations in 30 known fla genes on transcription from four operons in the hook gene cluster. These results show that the flaO (transcription unit III) and flbF (transcription unit IV) operons are located at or near the top of the hierarchy. They also reveal an extensive network of negative transcriptional controls that are superimposed on the positive regulatory cascade described previously. The strong negative autoregulation observed for the flaN (transcription unit I), flbG (transcription unit II), and flaO (transcription unit III) promoters provides one possible mechanism for turning off fla gene expression at the end of the respective synthetic periods. We suggest that these positive and negative transcriptional interactions are components of genetic switches that determine the sequence in which fla genes are turned on and off in the C. crescentus cell cycle.

Bacteria↗
PubMed1989

Critical importance of the triplet lifetime of photosensitizer in photodynamic therapy of tumor.

The relation between the lifetimes of the triplet states of various porphyrins and their photosensitizing effects on the photodynamic therapy (PDT) of tumor has been examined. Diethylene-triamine pentaacetic acid ester of 4-[1-(2-hydroxy-ethyloxy)ethyl]-2-vinyl deuteroporphyrin-IX gallium (III) complex (Ga-DP), zinc (II) complex (Zn-DP), and manganese (III) complex (Mn-DP) and Photofrin II (PII) are used as the photosensitizer. The triplet lifetimes have been measured for the samples adsorbed on filter paper (FP) and found to be 57 ms (Ga-DP), 26 ms (Zn-DP), less than or equal to 10 microseconds (Mn-DP) and 9 ms (PII). The phosphorescence of Ga-DP in tumor-bearing golden hamsters are measured both in tumor tissue and in liver. They show bi-exponential decay with the lifetimes of about 5 and 20 ms. From the values, the generation rate, kct[3O2], of singlet molecular oxygen in living animal tissue may be estimated to be an order of 10(2) s-1. The PDT effects have been quantitatively investigated for in vitro experiments; upon irradiation the growth inhibitions of mouse p388 leukemia cells are obtained as a function of concentration of Ga-DP, Zn-DP, Mn-DP and PII. The experimental results indicate that the PDT effects depend essentially on the triplet lifetimes of the photosensitizers.

Humans↗
PubMed1989

A biologically active insulin analogue with modification in the A2 position. [2-Valine-A] sheep insulin.

The synthesis and biological evaluation of [2-Valine-A] insulin ([Val2-A]insulin) is reported. In this insulin, the isoleucine residue in position A2, invariant in the majority of mammalian insulins, is substituted by valine. The same substitution, along with four others, occurs naturally in the insulin produced by the owl monkey. Owl monkey insulin exhibits ca. 20% of the activity of porcine insulin in in vitro insulin assays using human cells in culture. [Val2-A]insulin displays 20-22% of the activity of bovine insulin in in vitro insulin assays using rat liver plasma membranes or isolated rat adipocytes. We suggest that the substitution of valine for isoleucine at position A2 is responsible for all or most of the diminution in potency of owl monkey insulin relative to porcine insulin. The data are discussed with regard to previous findings with insulin analogues in which isoleucine A2 was replaced with norleucine, glycine and alanine.

Amino Acids↗
PubMed1989

Diagnosis of Fasciola sp. infections in cattle by enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was evaluated for diagnosis of experimental or naturally occurring Fasciola sp. infections in cattle. The positive rate for the ELISA in calves inoculated with Fasciola metacercariae were 21.1% by 2 weeks postinoculation (PI), 94.6% by 4 weeks PI and 100% by 6-21 weeks PI. The positive rate for the immunodiffusion test (Ouchterlony test) reached 91.7% by 2 weeks PI, however, it dropped to 77.8% by 10 weeks PI. The positive rate for the fecal egg examination was 0% by 10 weeks PI, 77.8% by 12 weeks PI and 100% by 14-21 weeks PI. The practical application of ELISA was tested by using 165 cows raised under field condition. All the 24 cows that were positive both in the fecal egg examination and the Ouchterlony test were ELISA positive. Of the 6 cows that were egg positive and Ouchterlony negative, 5 showed ELISA positive reactions. Of the 27 cows that were egg negative and Ouchterlony positive, 24 were ELISA positive. Of the 108 cows that were egg negative and Ouchterlony negative, 90 were ELISA negative. However, the other 18 cows had ELISA positive reactions. Our results suggested that the ELISA using crude adult antigen was superior to the Ouchterlony test and fecal egg examination for diagnosis of experimental or naturally occurring Fasciola sp. infections in cattle.

Animals↗
PubMed1989

Analysis of chironomid allergens using specific T cell lines and clones in humans.

To analyze the possible major T cell recognition site(s) of chironomid antigens, we established human T cell lines and clones (CD3+ 4+ 8-) reactive to soluble extracts of the adult midge of Tokunagayusurika akamusi (TAA) and/or Chironomus yoshimatsui (CYA). All T cell lines and clones proliferated heavily in response to relatively large molecular weight fractions of TAA (MW greater than or equal to 15,000). Nine clones reactive to TAA were classified into 3 groups according to reactivity, indicating the existence of at least 3 distinct T cell recognition sites in TAA. Five T cell clones responded to both TAA and CYA, although the two chironomid antigens were serologically distinct. We conclude that T cell recognition sites of chironomid antigens are different from B cell recognition sites in humans.

Allergens↗
PubMed1989

[Results of the treatment of prostatic cancer].

Two hundred and twenty patients with prostatic cancer were treated in our clinic during the past ten years between April, 1977 and March, 1987. The age distribution was from 45 to 91 years old and more than half of patients were in seventies. Stages A, B, C and D were 3.5%, 19.7%, 21.2% and 55.6%, respectively. Hormonal therapy was given in 175 cases (79.5%) as an initial treatment. The first therapy showed effectiveness in 181 (83.8%) of 216 cases; in 153 (87.4%) of 175 cases treated by hormonal therapy. Reactivation after the initial treatment was observed in 59 (32.6%) of 181 cases; in 48 (31.4%) of 153 cases treated by hormonal therapy. The interval between the start of treatment and reactivation for the stage D was significantly shorter than that for the other stages. Elevation of serum alkaline-phosphatase levels, accelerated erythrocyte sedimentation rate and hydronephrosis were significant risk factors for reactivation. Of the 220 cases, 51 (23.2%) died of advanced cancer. The overall 5-year survival rate was 41.2%. High grade and high stage were significantly related to the poor prognosis. In our studies, as hormonal therapy, maintenance on 100 mg of diethylstilbestrol diphosphate daily was found effective for the treatment of prostatic cancer.

Adenocarcinoma↗
PubMed1989

[Treatment of 46 cases of renal pelvic and ureteral tumors].

During about 10 years from November, 1977 to March, 1987, 46 patients with renal pelvic and ureteral tumors were treated at the Department of Urology, Hamamatsu University School of Medicine and the affiliated hospitals. There were 34 males and 12 females with the highest age incidence in the seventies. Histologically, 44 transitional cell carcinomas and 2 squamous cell carcinomas were found. Of the 44 transitional cell carcinomas, 1 was Tis; 13 T1, 2 T2, 8 T3, 15 M+ (with metastatic lesion), and 5 TX. As to grading, 1 was G1; 24 G2, 15 G3, and 4 GX. Staging was correlated with grading. The 5-year survival rates (Kaplan-Meier's method) were 37% in patients with transitional cell carcinoma. Among patients with transitional cell carcinoma, the 5-year survival rate was 43% for G2 and 42% for G3. As to staging, the 5-year survival rates were 71% and 46% in patients with stage of T1 and T3, respectively. No patient with M+ survived longer than 4 years. The 5-year survival rates were 38% and 34% in renal pelvic tumors (24 cases) and ureteral tumors (20 cases), respectively. As to the treatments, the 5-year survival rates after curable treatment (24 cases) and non-curable treatment (20 cases) were 63% and 7%, respectively.

Aged↗
PubMed1989

[Treatment of 255 patients with bladder tumors].

During about 10 years from November, 1977 to March, 1987, two hundreds and fifty-five patients with bladder tumors were treated at the Department of Urology, Hamamatsu University School of Medicine and the affiliated hospitals. There were 198 males and 57 females with the highest age incidence in the seventies. Histologically, 242, 11 and 2 tumors were of transitional cell, squamous cell and adenocarcinoma, respectively. Of the 242 transitional cell carcinomas, 7 were Tis; 43 Ta, 111 T1, 33 T2, 19 T3, 5 T4, 14 M+ (with metastatic lesion), and 10 TX. As to grading, 6 was G0; 66 G1, 100 G2, 64 G3, and 6 GX. Staging was correlated with grading. The 5-year survival rates (Kaplan-Meier's method) were 64% in patients with transitional cell carcinoma; 58% in those with squamous cell carcinoma. In patients with transitional cell carcinoma, the 5-year survival rates were 100% for G0, 73% for G1, 73% for G2 and 40% for G3. As to staging, the 5-year survival rates were 67%, 81%, 81%, 35%, 41%, 40% and 12% in patients with stage of Tis, Ta, T1, T2, T3, T4 and M+, respectively. As to the initial treatment, the 5-year survival rates after TUR (137 cases), partial cystectomy (4 cases) and total cystectomy (56 cases) were 81%, 36% and 61%, respectively. The rate of intravesical recurrence after TUR was evaluated with the cumulative non-recurrence rate calculated by Kaplan-Meier's method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Analysis of lymphocyte response to chironomid midge antigens in asthmatic and non-asthmatic individuals.

Chironomid antigens are currently one of the important allergens for bronchial asthma in Japan. We evaluated in vitro responses of peripheral blood lymphocytes (PBLs) to chironomid antigens and compared these responses with serum IgE levels. PBLs from adult asthmatic patients showed stronger proliferation in response to the extract of adult midges of Chironomus yoshimatsui compared with healthy adults. On the other hand, elevated PBL responses of child asthmatic patients to chironomid antigens were not observed. There was no significant correlation between PBL proliferation and the serum IgE level. Our results might suggest that elevated PBL proliferation in response to chironomid allergens has somehow important pathogenic roles in adult cases although this does not correlate directly with specific IgE production.

Animals↗
PubMed1989

Disappearance of specific antibodies in patients with chronic schistosomiasis japonica by treatment with praziquantel.

We tested effects of praziquantel, an antischistosomal compound, on clinical and immunological parameters of chronic schistosomiasis japonica. Two Japanese patients, who had high antibody titers to Schistosoma japonicum antigens but no fecal schistosome eggs or no or mild symptoms complained, were treated with praziquantel. Within two years after treatment, anti-schistosome antibodies in sera from the patients became negative in enzyme-linked immunosorbent assay. There was no significant alteration in cellular immunity to the parasite. Although S. japonicum infection is believed to have been eradicated in Japan, our present results seem to suggest the possibility that a few Japanese individuals, who have high anti-schistosome antibody, still harbor live parasites.

Animals↗
PubMed1989

HLA-linked immune suppression in humans.

There is no doubt that HLA-DR molecules are acting as the products of HLA-linked immune response genes (Ir-genes), because (i) HLA-DR molecules are the restriction elements in the interaction between CD4+ helper T cells and antigen-presenting cells (APC) to respond to many antigens such as streptococcal cell wall antigen (SCW) (Nishimura & Sasazuki, 1983; Sone et al., 1985; Hizayama et al., 1986), schistosomal antigen (Sj) (Hirayama et al., 1987), Mycobacterium leprae antigen (ML) (Kikuchi et al., 1986) and so on; and (ii) anti-HLA-DR monoclonal antibodies completely abolish the immune response to those antigens (Nishimura & Sasazuki, 1983; Sone et al., 1985). However, genetic analysis of the immune response to those antigens in families or populations revealed that responsiveness is recessive and non-responsiveness to those antigens is a dominant genetic trait that is tightly linked to HLA (Sasazuki et al., 1980a, 1983; Watanabe et al., 1988). This is completely opposite to the situation under the Ir-gene control where responsiveness is dominant and non-responsiveness is recessive. In this paper, we report evidence of how we came across the concept of HLA-linked immune suppression genes (Is-genes) besides Ir-genes, and show evidence for the epistatic interaction between HLA-DR and DQ to determine the immune response to several antigens in humans.

Genes, MHC Class II↗
PubMed1989

[Clinical significance of serum NCC-ST 439 as a tumor marker for colorectal cancer].

Clinical significance of preoperative serum NCC-ST 439 level was studied in 119 cases of colorectal cancer (90 of primary, 29 cases of recurrent). The positive rates for serum NCC-ST 439 were 28.9% in primary and 65.5% in recurrent cases. The false positive rates for benign disease were 5.6%. These rates were low when compared with those for other tumor markers. The positive rates for serum NCC-ST 439 exhibited a strong correlation with wall invasion, lymph node and liver metastases. A combination assay of NCC-ST 439, CEA and CA 19-9 produced a high positive rates as 43.3% in primary and 86.2% in recurrent cases. These results demonstrate that measurement of serum NCC-ST 439 may be useful for cancer staging and improves the diagnostic rate in combination with CEA and CA 19-9.

Adenocarcinoma↗