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Biomedical subjects

N Yoshida

Publications and source records attributed to N Yoshida.

At least 523 records · Page 29Linked to original sources
PubMed1987

Expression of human pancreatic secretory trypsin inhibitor in Saccharomyces cerevisiae.

Human pancreatic secretory trypsin inhibitor (PSTI) cDNA was expressed in Saccharomyces cerevisiae using the yeast acid phosphatase PHO5 promoter. The product encoded by the PSTI-coding cDNA was correctly processed in yeast cells, and the PSTI molecules were efficiently secreted into the medium. The amino acid composition and the N-terminal amino acid sequence of the secreted PSTI molecules were identical to those of the authentic PSTI polypeptides from human pancreas, and the product exhibited trypsin-inhibitory activity.

Acid Phosphatase↗
PubMed1987

Oligomeric structure of recombinant human and murine immune interferons by means of sedimentation equilibrium.

The oligomeric structure of two recombinant human immune interferon species, one with Cys-Tyr-Cys-Gln [( Cys-Tyr-Cys]rHu-IFN-gamma) and the other with Met-Gln-Asp-Pro (rHu-IFN-gamma) as the amino-terminal residues, and a recombinant murine immune interferon [( Cys-Tyr-Cys]rMu-IFN-gamma) were examined by means of sedimentation equilibrium. All three IFN-gamma s existed as dimers under nondenaturing conditions. Both [Cys-Tyr-Cys]rHu-IFN-gamma and [Cys-Tyr-Cys]rMu-IFN-gamma formed higher oligomers, tetramers, and octamers, respectively, under oxidative conditions, whereas rHu-IFN-gamma remained as dimers.

Animals↗
PubMed1987

Production of recombinant human pancreatic secretory trypsin inhibitor by Escherichia coli.

A synthetic gene for human pancreatic secretory trypsin inhibitor (PSTI) was fused to the coding sequence for the amino-terminal 135 amino acid residues of human interferon-gamma (IFN-gamma) by interposing a methionine codon sequence, and the resulting hybrid gene was efficiently expressed in Escherichia coli cells. Recombinant human PSTI (rHu-PSTI) was separated from the IFN-gamma/PSTI fused protein by cleavage at the methionine residue with cyanogen bromide. Finally, rHu-PSTI was purified by affinity chromatography on a bovine trypsin-CH-Sepharose 4B column. The amino acid composition, partial amino-terminal sequence, disulfide formation, human trypsin inhibitory activity, and immunoreactivity against rabbit anti-human PSTI serum of rHu-PSTI corresponded to those of the natural form.

Amino Acid Sequence↗
PubMed1987

Trypanolytic activity and antibodies to metacyclic trypomastigotes of Trypanosoma cruzi in non-Chagasic human sera.

Metacyclic trypomastigotes of Trypanosoma cruzi, derived either from triatomid vectors or axenic cultures, were found to be extensively lysed by sera of some non-Chagasic healthy individuals through activation of the alternative complement pathway. Antibodies to T. cruzi metacyclics were detected by direct agglutination test in normal human sera (NHS) containing trypanolytic activity. Absorption of lytic NHS with metacyclic trypomastigotes, but not with non pathogenic Herpetomonas samuelpessoai promastigotes, abolished the trypanolytic effect. Natural antibodies to trypomastigotes were not found in NHS devoid of trypanolytic activity. Precipitation of 131I-labelled metacyclic surface proteins with lytic NHS revealed as the major band a polypeptide with an apparent molecular weight of 75,000.

Adult↗
PubMed1987

Changes in free progesterone in the serum, peritoneal fluid and follicular fluid through the menstrual cycle and pregnancy.

Progesterone is said to play an important role in the secretory transformation of the endometrium, maintenance of gestation and relaxation of the myometrium. Progesterone is also said to be involved in ovulation and fertilization, and is contained in large amounts in the follicular fluid and peritoneal fluid. As with other steroid hormones, progesterone exists in the blood in protein-bound and free forms, and it is the free form which exhibits biological activity. In order to evaluate the biological activity of progesterone, we determined the percent free progesterone, employing the method used by Vlahos et al. for the determination of testosterone. No significant difference was noted between the percent free progesterone in the follicular phase (4.44 +/- 0.30%) and luteal phase (4.77 +/- 0.26%) of the menstrual cycle. However, a tendency for the percent free progesterone to rise was recognized in the first, and the value significantly increased to 5.54 +/- 0.51% in the third trimester (p less than 0.005). The percent free progesterone during the follicular phase in the peritoneal fluid was 4.95 +/- 0.30%, and in the follicular fluid, 5.39 +/- 0.22%, both values being larger than the value in the serum during the same phase.

Adult↗
PubMed1987

Determination by ultrafiltration of the fraction of unbound estradiol and its variation in peritoneal fluid during the menstrual cycle.

An ultrafiltration method employing a Centrifree filter for determining the unbound fraction of estradiol was studied. Centrifugation was performed under conditions similar to those in vivo. Good correlation was recognized between this method and the equilibrium dialysis. This method was employed to determine the unbound fraction of estradiol in the serum and the peritoneal fluid of 26 infertility patients classified according to their menstrual dates. The total estradiol and progesterone contents in the peritoneal fluid were high after ovulation. There was no significant difference in the percentage of unbound estradiol in the serum among various groups. In the peritoneal fluid, however, the percentage of unbound estradiol for the day 12-14 patients was 4.5 +/- 0.2% in contrast with 3.8 +/- 0.4% for the day 15-18 group (p less than 0.05) and 3.5 +/- 0.1% (p less than 0.05) for the day 19-28 group. Moreover, the fraction (4.5%) of unbound estradiol in the peritoneal fluid of a patient with luteinized unruptured follicle (LUF) syndrome was comparable with that of patients in the follicular phase. The difference between the percentage of unbound estradiol in the peritoneal fluid before and after ovulation is considered to be due to the transudation of follicular estradiol in the follicular phase and the exudation of estradiol from the corpus luteum into the peritoneal cavity in the luteal phase.

Ascitic Fluid↗
PubMed1987

[A case report of multiple endocrine neoplasia type 2b].

A 10-year-old girl was admitted displaying a medullary thyroid carcinoma, accompanying neurinomas of the tongue, marfanoid habitus, megacolon, and scoliosis. Although her adrenal glands were found to be unremarkable on both CT and ultrasonogram examination an MIBG scintiscan showed a 131-1 uptake, suggesting the presence of medullary hyperplasia. Remarkable nodal involvement with invasive features witnessed in the upper mediastinum during tertiary surgery four years later, following a total thyroidectomy. The TCT and CEA profiling was not sufficient enough to predict a recurrence. At the present state there is difficulty in providing an early diagnosis; through node dissection, however, is considered to be necessary at time of primary thyroid operation in cases with MEN type 2b.

Carcinoma↗
PubMed1986

Purification and characterization of recombinant murine immune interferon.

The recombinant murine immune interferon (rMu-IFN-gamma) was purified to homogeneity from Escherichia coli harboring the expression vector of murine IFN-gamma. The purified rMu-IFN-gamma showed an Mr of 15 000 in SDS-polyacrylamide gel electrophoresis. Results of amino acid analysis, amino- and carboxyl-terminal analyses and peptide mapping of rMu-IFN-gamma suggest that it has the complete protein sequence predicted on the basis of cDNA except for lack of four amino acid residues from the mature carboxyl-terminus.

Amino Acid Sequence↗
PubMed1986

Mechanism of resistance to lysis by the alternative complement pathway in Trypanosoma cruzi trypomastigotes: effect of specific monoclonal antibody.

Trypanosoma cruzi G strain epimastigotes were lysed by normal human serum (NHS) through activation of the alternative complement pathway (ACP), whereas metacyclic trypomastigotes were resistant to lysis. Epimastigotes and metacyclics with equivalent amounts of C3b deposited on their surface bound factor B with similar affinities. In contrast, factor H bound with higher affinity to metacyclics than to epimastigotes. Both T. cruzi forms with bound C3b were extensively (60 to 80%) lysed after formation of surface C3-convertase and the addition of a C3-C9 complement source. In the presence of factors H and I, or incubation with NHS with EDTA, the percentage of lysis of metacyclics decreased faster than that of epimastigotes with increasing incubation times. These data suggest, as a possible mechanism of resistance to lysis in metacyclic trypomastigotes, the higher binding affinity of factor H to C3b and the inactivation of the latter by serum regulatory proteins. Metacyclics were lysed by NHS, through ACP, in the presence of human immune serum to T. cruzi or anti-T. cruzi monoclonal antibody, but not with the Fab fragment of the latter, which recognizes a 90,000 m.w. antigen from T. cruzi metacyclics. Protection of parasite-bound C3b from serum control proteins was observed when parasites were incubated, before C3 deposition, with the lytic monoclonal antibody but not with its Fab fragment or a nonrelated IgG control. When C3b was deposited on metacyclics before antibody binding, C3b inactivation occurred. In the lysis of metacyclics, through ACP activation, binding of antibody apparently creates new acceptor sites which prevent the activity of serum regulatory proteins.

Animals↗
PubMed1986

Excessive fibrinolysis in suspected amyloidosis: demonstration of plasmin-alpha 2-plasmin inhibitor complex and von Willebrand factor fragment in plasma.

We performed a hemostatic evaluation in detail in a patient with suspected amyloidosis who was suffering from several bleeding episodes. He had a shortened euglobulin clot lysis time, decreased alpha 2-plasmin inhibitor (alpha 2-PI), decreased plasminogen, elevated tissue-type plasminogen activator (t-PA), elevated plasmin-alpha 2-PI complex, and decreased ratio of ristocetin cofactor to von Willebrand factor (vWF) antigen. Fibrinogen and fibrin/fibrinogen degradation products levels fluctuated, with abnormal values on several occasions. On crossed immunoelectrophoresis, plasmin-alpha 2-PI complex and vWF fragment were demonstrated in the patient plasma. These abnormal findings and bleeding symptoms improved following the administration of tranexamic acid. Discontinuation of tranexamic acid resulted in deterioration of these parameters. These observations indicate that pathologic fibrinolysis (continuous intravascular plasmin generation) characterized by the consumption of alpha 2-PI and plasminogen, formation of plasmin-alpha 2-PI complex, and fragmentation of vWF contributed to the bleeding in this patient. It is important to recognize excessive fibrinolysis as the underlying cause of bleeding in these patients, since specific treatment with antifibrinolytic agents is effective in controlling the bleeding.

Amyloidosis↗
PubMed1986

Trace element content in two species of whale tapeworms, Diphyllobothrium macroovatum and Diplogonoporus balaenopterae.

Trace elements in two species of whale tapeworms, Diphyllobothrium macroovatum and Diplogonoporus balaenopterae, were analysed by atomic absorption spectroscopy. Six elements (Fe, Cu, Zn, Mn, Cd, Ca) were assayed from different regions of two tapeworms: scolex, neck, immature, mature and gravid proglottids. Whole strobilae at different stages of maturity were also examined. The relationship between the trace element content and the physiological significance is discussed.

Animals↗
PubMed1986

Lipopolysaccharide-induced colitis in rabbits.

An experimental animal model of human ulcerative colitis using lipopolysaccharide (LPS) was studied. Rabbits were skin-sensitized by LPS and challenged with intrarectal instillation of LPS after 1% formalin enema. The course of experimental colitis was followed by performing serial colonofiberscopic examinations and biopsy. Petechiae appeared from the 8th hour, and ulcers and bleeding on the 3rd day. Mild macroscopic changes continued for about 2 weeks. By repeating the LPS enema after the initial treatment, the colitis was maintained for over 1 month. Control groups without formalin enema revealed no macroscopic changes, and the groups with only formalin enema showed mild transient changes. The endotoxin level in the blood during the experiment increased (36 pg/ml) at 24 h after the treatment in the LPS-sensitized group, while non-sensitized control rabbits had higher levels of endotoxin. Though fibrinogen and PTT levels had increased at 24 and 72 h, these levels were marked in the control rabbits. The direct reaction of LPS was minimal, and local immune reaction by LPS seems to play an important role in the perpetuation of experimental colitis. Tissue fibrinolysis of the colon increased significantly as the mucosal damage appeared. This experimental colitis with LPS may be useful as a model of human ulcerative colitis.

Animals↗
PubMed1986

Trypanosoma cruzi: recognition of trypomastigote surface antigens by lytic antisera from mice resistant to acute infection.

The complement-dependent lytic activity of various mouse antisera to Trypanosoma cruzi was tested, using purified culture metacyclic trypomastigotes as targets, in an attempt to verify the correlation between resistance to T. cruzi and lytic antibodies, Sera of mice immunized with killed trypomastigotes, which resisted acute infection by insect-derived metacyclics of T. cruzi, consistently lysed over 95% of trypomastigotes in vitro. In contrast, fewer than 50% of parasites were lysed by sera of mice immunized with killed epimastigotes, which, upon challenge with metacyclic forms, developed high parasitemias comparable to those of non-immunized controls. All immune sera with high lytic activity, namely sera of mice immunized with killed trypomastigotes and sera of chronically infected mice, reacted with a set of 131I-labeled trypomastigote surface proteins with apparent molecular weights of 77,000, 82,000, and 88,000, which failed to be recognized by sera of mice immunized with epimastigotes, Absorption of lytic sera with trypomastigotes, but not with epimastigotes, greatly reduced the ability to lyse trypomastigotes and to precipitate the surface polypeptides.

Animals↗
PubMed1986

Stage-specific surface antigens of metacyclic trypomastigotes of Trypanosoma cruzi identified by monoclonal antibodies.

Stage-specific Trypanosoma cruzi surface antigens were characterized by using monoclonal antibodies (MAb) which bind specifically to the metacyclic trypomastigotes derived from either the insect vector or acellular cultures. A protein with an apparent molecular weight of 90,000 was detected by the MAb 5E7 on the surface of cultured metacyclics of four strains of T. cruzi: G, CL, Y and Tulahuen. The MAb 1G7, which binds to an epitope of the 90 kDa antigen distinct from that recognized by the MAb 5E7, reacted with metacyclics of the G and Tulahuen strains but not of the Y or CL strain. A polypeptide of approximately 82 kDa, identified by the MAb 3F6, was found in the metacyclics of all four T. cruzi strains. The MAb 3F6 also detected a 75 kDa antigen in the G strain metacyclics. The stage-specific MAb and the polyclonal antibodies from mice protected against acute T. cruzi infection by immunization with killed G metacyclics identified the same set of major surface proteins of G metacyclic trypomastigotes.

Animals↗
PubMed1986

Cross-reactive polysaccharides from Trypanosoma cruzi and fungi (especially Dactylium dendroides).

Cross-reactivity between fungal and Trypanosoma cruzi polysaccharides, owing to common residues of beta-D-galactofuranose, beta-D-galactopyranose, and alpha-D-mannopyranose, was demonstrated by using rabbit immune sera against T. cruzi epimastigotes and sera from patients with Chagas' disease. Several chagasic (Ch) sera precipitated partly purified galactomannans from Aspergillus fumigatus and from T. cruzi epimastigotes and also the galactoglucomannan from Dactylium dendroides. Reaction of one Ch serum with T. cruzi galactomannan (GM) was completely inhibited by synthetic beta-D-Galf-(1----3)-Me alpha-D-Manp, and that of another Ch serum with a purified D. dendroides galactoglucomannan (GGM) was partly inhibited by (1----6)-linked (81%) or by (1----3)-linked (33%) beta-D-Galf-Me alpha-D-Manp. The beta-D-Galf-(1----3)-alpha-D-Manp epitope was present in both T. cruzi and D. dendroides polysaccharides. Rabbit anti-T. cruzi antisera precipitated A. fumigatus GM, T. cruzi antigenic extracts containing the lipopeptidophosphoglycan (LPPG), T. cruzi alkali-extracted GM, a synthetic GM, and D. dendroides GGM. Weak reactivities were obtained for a Torulopsis lactis-condensi GM containing beta-D-Galp terminal residues and for baker's yeast mannan with alpha-D-Manp-(1----3)-alpha-D-Manp-(1----2)-alpha-D-Manp+ ++-(1----2) side chains. An anti-LPPG rabbit serum precipitated D. dendroides GGM--a reaction inhibited (82%) by beta-D-Galf-(1----3)-Me alpha-D-Manp and. less efficiently, by a (1----5)-linked beta-D-Galf-tetrasaccharide. Sera from mice immunized with D. dendroides whole cells reacted with CL-strain trypomastigotes as shown by indirect immunofluorescence, by a Staphylococcus adherence test, but were not lytic. Mice immunized with D. dendroides were not protected against a challenge with virulent T. cruzi trypomastigotes.

Animals↗