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Biomedical subjects

N Yoshida

Publications and source records attributed to N Yoshida.

At least 469 records · Page 26Linked to original sources
PubMed1989

Demonstration of mother-to-infant transmission of hepatitis B virus by means of polymerase chain reaction.

To investigate the failure of vaccines to prevent mother-to-infant transmission of hepatitis B virus (HBV), serum, cord blood, and colostrum samples from eleven mothers, known to be carriers of hepatitis B surface antigen, and their infants were examined by means of a highly sensitive polymerase chain reaction (PCR) method. HBV-specific DNA was detected in ten maternal serum samples, eight samples of colostral whey, eight samples of colostral cells, and one cord blood sample. Four infants of mothers with HBV-DNA-positive colostrum showed low responsiveness to hepatitis B vaccine. The infant whose cord blood was positive for HBV DNA showed low responsiveness to hepatitis B vaccine and subsequently became an HBV carrier. These results suggest the need for further study to evaluate whether breastfeeding is advisable for HBV carriers.

Carrier State↗
PubMed1989

The primary structure of a membrane-associated phospholipase A2 from human spleen.

The complete primary structure of membrane-associated phospholipase A2 purified from a human splenic membrane fraction was determined by sequence analysis of the peptides generated by lysyl endopeptidase and Staphylococcus aureus V8 protease cleavage. The enzyme consists of 124 amino acid residues corresponding to a molecular weight of 13,904. The primary structure reveals the characteristics of Group II phospholipases A2 and a large ratio of basic amino acid residues to acidic ones, that ratio being 3.4 : 1.

Amino Acid Sequence↗
PubMed1989

cDNA cloning and sequence determination of rat membrane-associated phospholipase A2.

Based on the partial amino acid sequences of membrane-associated phospholipase A2 (PLA2M), belonging to group II, purified from rat spleen, the cDNA encoding PLA2M was cloned by a new cloning strategy utilizing enzymatic cDNA amplification. At the N-terminus of the coded 146 residues, which were deduced from the cDNA sequence, the putative signal peptide was found despite the tight adherence of this enzyme to the membrane. The sequence of rat PLA2M exhibits 75% homology with that of human group II PLA2 in the protein-coding region. The result of RNA blot analysis showed that rat ileal mucosa contains the largest amount of the PLA2 transcript among the tissues examined.

Amino Acid Sequence↗
PubMed1989

A monoclonal antibody that triggers deacylation of an intermediate thrombin-antithrombin III complex.

Upon incubation of antithrombin III with thrombin in the presence of a monoclonal antibody recognizing an epitope exposed on the heavy chain part of thrombin-cleaved two-chain antithrombin III, antithrombin III was preferentially cleaved by the enzyme as a substrate, rather than covalently complexed with the enzyme to form an equimolar, stable acyl complex. Once the stable acyl complex was formed between the enzyme and antithrombin III, however, no further liberation of two-chain antithrombin III was observed. Kinetic studies showed that heparin does not affect this reaction, although generation of thrombin-cleaved two-chain antithrombin III is apparently accelerated in accordance with the rate constant for heparin-enhanced thrombin-antithrombin III complex formation. Here we propose the term "switching antibody" for an antibody that triggers deacylation of an intermediate enzyme-inhibitor complex by switching the enzyme-inhibitor reaction from the major pathway of stable acyl complex formation to an alternative pathway of cleavage of the inhibitor as a substrate.

Antibodies, Monoclonal↗
PubMed1989

Structural relationship among the members of a multigene family coding for the sweet potato tuberous root storage protein.

Sporamin, the major soluble protein of the sweet potato tuberous root, is coded for by a multigene family. Fourty-nine essentially full-length sporamin cDNAs isolated from tuberous root cDNA library have been classified by cross hybridization, restriction endonuclease cleavage pattern and ribonuclease cleavage mapping. All the cDNAs fall into one of the two distinct homology groups, subfamilies A and B, which correspond to the polypeptide classes sporamin A and B, respectively. At least 5 different sequences are detected in both of the 22 sporamin A and 27 sporamin B cDNAs. Comparison of the nucleotide sequences of the coding region of three each of sporamin A and B subfamily members, four from cDNAs and two from genomic clones, indicates that intra-subfamily homologies (94 to 98%) are much higher than inter-subfamily homologies (82 to 84%), and there are deletions or insertions of one or two codons at three locations which characterize each subfamily. Large portions of base substitutions in the coding region accompany amino acid substitutions. In contrast to the coding region, most of the structural differences among the members in the 5' and 3' noncoding regions are deletions or insertions.

Amino Acid Sequence↗
PubMed1989

Site-directed mutagenesis of human pancreatic secretory trypsin inhibitor.

Arg-42 or Lys-43 or Arg-44 of human pancreatic secretory trypsin inhibitor (PSTI) was replaced by Thr or Ser by site-directed mutagenesis, and the inactivation rates of the mutants after mixing with human trypsin were compared with that of the natural form. The inactivation rate decreased for one mutant (Arg-44----Ser), whereas no change was observed for another (Arg-42----Thr) and an increase was observed for a third (Lys-43----Thr). Kinetic studies on the interactions between human trypsin and synthetic peptides, comprising the regions of Phe39-Ser47 of the respective PSTI species, showed that human trypsin cleaved the Arg42-Lys43 bond preferentially to the Arg44-Gln45 bond. However, it is cleavage of the latter bond that is thought to cause inactivation of human PSTI. These results suggest that the Arg44-Gln45 bond of human PSTI is responsible for its inhibitory activity, and inactivation of human PSTI is probably caused by deletion of the dipeptide Lys43-Arg44.

Amino Acids↗
PubMed1989

[A child case of Down's syndrome with intestinal tuberculosis and tuberculous pleuritis].

A 13 year-old girl with Down's syndrome was admitted to our hospital with a very positive reaction to PPD 5TU, abnormal shadow on the chest X-ray films and diarrhea. She suffered from acute enterocolitis one year ago, and then has been complaining of abdominal pain, appetite loss, and weight loss for a year. After admission, she was diagnosed as tuberculous pleuritis and suspected intestinal tuberculosis by laboratory examination. She recovered without sequelae by the combination therapy of SM, INH, and RFP, and was discharged after 5 months. The diagnosis of intestinal tuberculosis was confirmed by Colon Fiberscopy showing ulceration at the ileocecal region and simultaneous biopsy showing granuloma. Surgical treatment was not reserved, because she had no complications namely perforation and fistulization. We estimated that the onset of intestinal tuberculosis coincided with the acute enterocolitis which she had about one year ago. We realized the importance of paying attention to intestinal tuberculosis in the differential diagnosis of enterocolitis, especially regional enteritis. Furthermore, in the therapy of the immunocompromised host including Down's syndrome, we must pay attention to extra-pulmonary tuberculosis. Efficiency of SM for intestinal tuberculosis with complications was confirmed.

Adolescent↗
PubMed1989

Metacyclic neutralizing effect of monoclonal antibody 10D8 directed to the 35- and 50-kilodalton surface glycoconjugates of Trypanosoma cruzi.

It was shown in this work that the infectivity of metacyclic forms of Trypanosoma cruzi was affected upon interaction with the monoclonal antibody (10D8), which reacts with a carbohydrate epitope of the 35- and 50-kilodalton (kDa) surface glycoconjugates. The invasion of Vero cells by metacyclic forms of strains Tulahuen and G was inhibited 50 to 67% in the presence of 10D8 (10 micrograms/ml), whereas a nonrelated monoclonal antibody to Plasmodium berghei had no such effect. In mice that were inoculated with metacyclic forms preincubated with 10D8 or that had passively received 10D8 before challenge with metacyclic forms, a considerable decrease in the parasitemia levels was observed. The 35- and 50-kDa antigens were detectable by the galactose oxidase and sodium boro[3H]hydride procedure but not by surface iodination or metabolic labeling with [35S]methionine, suggesting that they may be of glycolipid nature. The finding that the 35- and 50-kDa antigens are major bands recognized by sera of mice immunized with killed metacyclic forms and protected against acute infection, in addition to the results with 10D8, indicate that these glycoconjugates may play an important role in the metacyclic form-host cell association that initiates T. cruzi infection.

Animals↗
PubMed1989

An enzyme-linked immunosorbent assay for quantitation of aromatase cytochrome P-450.

Traditionally, aromatase has been quantified as aromatase activity according to its ability to produce estrogen from androgen. We have developed a quantitative assay based on the protein mass of catalytically active aromatase cytochrome P-450. A solid phase sandwich enzyme-linked immunosorbent assay for aromatase cytochrome P-450 has been devised using mouse monoclonal antibody (MAb3-2C2) and rabbit polyclonal antiserum (PAb R-8-2). Two rabbit antisera (PAb R-8-1 and R-8-2) were raised by immunization against human placental aromatase cytochrome P-450 which had been isolated by immunoaffinity chromatography of MAb3-2C2-coupled to Sepharose 4B resin. Both antisera were capable of suppressing human placental aromatase activity with IC50 values of 0.6 and 0.8 microliter/ml incubate, respectively, and showed monospecific to aromatase cytochrome P-450 in the Western blot analyses. Solubilized human placental microsomal samples were incubated in microtiter wells precoated with MAb3-2C2. The unbound proteins were washed out, and the aromatase cytochrome P-450 bound with the MAb3-2C2 in the wells was then reacted with PAb R-8-2, the binding of which was subsequently probed with goat antirabbit immunoglobulin G antibody alkaline phosphatase conjugate. Immunoaffinity-purified aromatase cytochrome P-450 of human placental microsomes was used for the standard, with the current assay detection limit at 1 ng/ml. There was a positive correlation between aromatase activity and the immunoreactive aromatase cytochrome P-450 level in solubilized microsomal samples after preincubation at 22 and 37 C, indicating that the enzyme-linked immunosorbent assay measures the level of aromatase cytochrome P-450 that has catalytic activity. The mean level of aromatase cytochrome P-450 in solubilized human term placental microsomes was 16.4 +/- 10.3 (+/- SD) micrograms/ml, corresponding to 0.38 +/- 0.19% of the original microsomes. The mean specific activity of aromatization of the solubilized samples was 0.650 +/- 0.163 nmol estrogen formed/min.mg protein. These results indicate that aromatase in the solubilized placental microsomal fraction has catalytic ability of 5.3 +/- 1.6 min-1 based on the immunoassayable cytochrome P-450.

Antibodies, Monoclonal↗
PubMed1989

Role of lipid peroxidation and oxygen radicals in compound 48/80-induced gastric mucosal injury in rats.

Repeated administration of a small dose of compound 48/80 induced acute gastric mucosal injury in rats. Thiobarbituric acid (TBA) reactants in the gastric mucosa were significantly increased and serum alpha-tocopherol was significantly decreased after the treatment. The total area of gastric lesions and the increase in TBA reactants in the gastric mucosa were significantly reduced by pretreatment with superoxide dismutase (SOD) and/or catalase, allopurinol and anti-rat polymorphonuclear leukocytes (PMN) antibody. Lipid peroxidation and oxygen radicals derived from both the xanthine-xanthine oxidase system and PMN may be involved in the pathogenesis of compound 48/80-induced gastric mucosal injury.

Animals↗
PubMed1989

Pathogenesis of platelet-activating factor-induced gastric mucosal damage in rats.

Platelet-activating factor (PAF), given intravenously, induced erosions and hyperemia to the rats stomachs. Gastric mucosal blood flow was decreased and thiobarbituric acid (TBA) reactants (an index of lipid peroxidation) in the gastric mucosa were increased 10 min after PAF injection. Superoxide dismutase plus catalase reduced the gastric mucosal lesions and TBA reactants, but had no influence on gastric mucosal blood flow. A reduction in the number of circulating polymorphonuclear leukocytes (PMN) reduced the gastric mucosal damage and TBA reactants, and inhibited the decrease in gastric mucosal blood flow, as observed 30 and 60 min after PAF injection. PAF induced superoxide production by rat PMN and enhanced that stimulated by opsonized zymosan or phorbol myristate acetate. These results suggest that microcirculatory disturbance and oxygen-derived free radicals generated by PMN play important roles in gastric mucosal lesions induced by PAF.

Animals↗
PubMed1989

[Hepatitis B virus and epidemiological study on efficacy of HBIG and vaccine for the prevention of type B hepatitis after accidental exposures among medical staffs (2)].

The best method of preventing HBV is accurate perception on the part of the patient. There is a need for sufficient care regarding patient blood with HBsAg (+), HBeAg (+) and HBc high-antibody titer. The following is a report on a follow-up survey regarding antibody titer following dosages of HBIG 2 V and 1 V and administration of a vaccine along with dosage of HBIG 1 V. 1. Dosage of HBIG 2V: (Female) Antibody titer was recognized two days following dosage. It continued for two weeks and disappeared after four weeks. (2) (Male) Antibody titer was recognized one day following dosage but disappeared after two weeks. 2. Dosage of HBIG 1 V: (Female) Antibody titer (-) was recognized two days after dosage and nine days after dosage. It continued for about one month and disappeared after five months. 3. Administration of three vaccines and dosage of HBIG 1 V: (Female) Antibody titer was recognized two days after HBIG 1 V dosage and continued for 18 days but disappeared after three months. Antibody titer was recognized again after about eight months and showed signs of continuing for 13 months.

Female↗
PubMed1989

[Basic investigation of saliva and serum SIgA].

The local immune mechanisms of which the IgA system is central are characterized by activity that is independent of the immune response of the body as a whole. Among these mechanisms, SIgA (secretory IgA) plays an important role. In measuring saliva/serum SIgA, the author used an EIA SIgA column set for saliva and for serum. Investigation of saliva SIgA concerned the correlation with saliva flow speed while investigation of serum SIgA concerned patients with oral dysfunctions and those inoculated with the HB preventive vaccine. A slightly negative correlation was observed between the saliva flow speed and the saliva SIgA value. Regarding serum SIgA, effect from the liver function was considered to be a factor among patients with oral dysfunctions. The antibody positive subjects among those inoculated with the HB vaccine are considered to reflect the response level of the antibody factor as well as individual differences in sensitivity and immune response. Among antibody negative subjects, however, there was a general tendency toward high values.

Humans↗
PubMed1989

[Role of polymorphonuclear leukocytes and oxygen-derived free radicals in the formation of gastric mucosal lesions induced by platelet-activating factor].

Gastric hemorrhagic erosions were induced by the administration of platelet-activating factor (PAF). Gastric wall blood flow was decreased and thiobarbituric acid (TBA) reactants in the gastric mucosa were increased 10 min after PAF injection. SOD and catalase reduced gastric mucosal lesions and TBA reactants, but had no influence on gastric blood flow. In polymorphonuclear leukocytes (PMN)-depleted rats, gastric mucosal lesions and TBA reactants in the gastric mucosa were reduced and gastric blood flow were increased. PAF induced the superoxide production from rat PMN in a dose dependent manner. These results suggest that oxygen-derived free radicals produced by PMN and lipid peroxidation may play an important role in the pathogenesis of gastric mucosal injury induced by PAF.

Animals↗