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Biomedical subjects

H Nagata

Publications and source records attributed to H Nagata.

At least 235 records · Page 13Linked to original sources
PubMed1991

Antiplatelet autoantibody-related microparticles in patients with idiopathic (autoimmune) thrombocytopenic purpura.

We used flow cytometry to detect antiplatelet antibody-related microparticles (MP) in 56 patients with idiopathic thrombocytopenic purpura (ITP). We measured MP in platelets following various types of stimulation in two experimental systems. In one system washed platelets were incubated with normal serum which included the complement system, and in the other, washed platelets were incubated with Tyrode's buffer. There were no differences between the two measurement systems in the degree of increase in MP using various agonists. An increase in MP using ITP plasma was found in 12 out of 56 patients. In particular, four patients showed a significant increase in MP in washed platelets (WP) plus serum. Furthermore, the increase in platelet-associated IgM (PAIgM) was significant in these patients. There was also a definite positive correlation between PAIgM and the percentage of MP of WP plus serum. On the other hand, no specificity for MP formation with anti-GPIIb/IIIa or anti-GPIb autoantibodies was observed. IgM antibody-related MP appear to exist in some patients with ITP.

Adolescent↗
PubMed1991

Involvement of platelet-activating factor in endothelin-induced vascular smooth muscle cell contraction.

This study was designed to elucidate the participation of platelet-activating factor (PAF) in endothelin-induced vascular constriction in vivo and in vitro. The microvascular hemodynamic changes in rat mesentery induced by the superfusion of endothelin-1 (ET-1) were visualized through an intravital microscopic system. It was revealed in vivo that ET-1 in a range of 100 fM-10 pM caused a sustained arteriolar constriction in a dose-dependent manner. Pretreatment with CV-6209, a selective PAF antagonist, significantly attenuated the constrictive change in arterioles. Changes of intracellular Ca2+ mobilization after treatment with ET-1 were investigated in vitro using a cell line (A-10 cell) derived from rat arterial smooth muscle cells. ET-1 caused a prompt rise in the fura-2-associated fluorescence intensity in the individual A-10 cell and it fell to a lower plateau level that was still higher than the baseline value. CV-6209-pretreated cells did not show the rapid-phase mobilization of Ca2+, but showed the slow late phase of Ca2+ activation. The present study demonstrates that PAF may be involved in endothelin-induced microvascular constriction by mediating the mobilization of Ca2+ in vascular smooth muscle cells.

Animals↗
PubMed1991

Synergistic action in platelet activation induced by an antiplatelet autoantibody in ITP.

We detected an autoantibody which activated normal platelets in a patient with immune thrombocytopenic purpura and investigated the mechanism by which this autoantibody mediated platelet activation. The patient's IgG induced platelet aggregation and ATP secretion in normal platelet-rich plasma (PRP). IgG-induced aggregation was inhibited by aspirin (ASA), apyrase, a protein kinase C (PKC) inhibitor and two anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibodies. The increase of aequorin-detected intraplatelet Ca2+ induced by the patient's IgG was extremely slight. Phosphorylation of a 40 kDa protein was induced by the patient's IgG without any obvious phosphorylation of a 20 kDa protein, and was inhibited by a PKC inhibitor but not by ASA. With ASA-treated normal PRP, the patient's IgG failed to induce aggregation itself, but enhanced ADP- or STA2-induced aggregation. Western blotting and immunoprecipitation experiments showed that the patient's IgG reacted to a protein of 36 kDa. These results suggest that the platelet activation induced by this autoantibody depended on both the selective activation of PKC and the slight Ca2+ mobilization induced by thromboxane A2 synthesis, while the aggregation depended on secretion induced by the synergistic action of the above two mechanisms and was mediated through GP IIb/IIIa.

Adenosine Triphosphate↗
PubMed1991

New monoclonal anti-human Fc gamma receptor II antibodies induce platelet aggregation.

We developed two new monoclonal antibodies, designated NNKY3-2 and NNKY4-7, that recognized a 40-kD platelet protein. They appeared to be monoclonal anti-Fc gamma receptor II (Fc gamma RII) antibodies from the results of flow cytometric binding inhibition studies using another monoclonal anti-Fc gamma RII antibody (2E1). The addition of NNKY3-2 or NNKY4-7 to platelet-rich plasma (PRP) led to a typical aggregation pattern preceded by a lag phase, but their addition to washed platelets did not induce aggregation. The aggregation of PRP by these antibodies was inhibited by prostaglandin E1 (PGE1) or staurosporine (protein kinase C inhibitor), whereas it was only slightly affected by a monoclonal anti-GPIIb/IIIa antibody or Arg-Gly-Asp-Ser. Furthermore, these antibodies induced the aggregation of washed platelets plus normal serum, but not that of washed platelets plus heat-treated serum (destruction of complement activity). These results suggest that NNKY3-2 or NNKY4-7-induced aggregation involves an unusual pathway independent of fibrinogen, and that the important factor is the participation of complement. NNKY3-2 and NNKY4-7 may be useful to study the relationship between autoantibodies, the Fc receptor, and complement in idiopathic thrombocytopenic purpura.

Adenosine Diphosphate↗
PubMed1991

Purification and properties of neuraminidase from the culture medium of Bacteroides loescheii.

Neuraminidase was purified from the culture medium of Bacteroides loescheii ATCC 15930 by ultrafiltration followed by a DEAE-Sephacel anion exchange chromatography, fast-protein liquid chromatography using Mono P column and high-performance liquid chromatography using a Shim-pack Diol-300 column. The molecular weight of the purified enzyme was measured to be approximately 87 kDa and the optimal pH was at 4.8. Although the enzyme was able to hydrolyze the substrates with alpha,2-3, alpha,2-6, and alpha,2-8 linkages of N-acetylneuraminic acid, the rate of hydrolysis of N-acetylneuraminosyl-alpha,2-3-lactose was greater than that of the alpha,2-6-isomer.

Bacteroides↗
PubMed1991

Influences of antiplatelet autoantibodies on platelet function in immune thrombocytopenic purpura.

We investigated the characteristics of the antiplatelet autoantibodies in 60 patients with ITP. Using flow cytometry, the binding of monoclonal antibodies to the platelet glycoprotein (GP) IIb/IIIa complex and to GPIb was examined in these patients. The extent of binding was decreased in 15 patients (anti-GPIIb/IIIa in 12 patients and both anti-GPIIb/IIIa and anti-GPIb in 3 patients). Western blotting revealed that 10 of these 15 patients had either anti-GPIIb or anti-GPIIIa and 2 had anti-GPIb autoantibodies, ADP-induced aggregation of normal platelets was inhibited by autoantibodies in 12 of 60 patients, and 11 of these had anti-GPIIb/IIIa antibodies. Ristocetin-induced aggregation was inhibited in 4 of these patients, and 2 with prominent inhibition had anti-GPIb antibodies. There was a significant relationship between platelet-associated IgG value and ATP secretion. These results suggest that some antiplatelet autoantibodies can affect platelet function and thus have an influence on the pathophysiology of ITP.

Adenosine Diphosphate↗
PubMed1991

Inhibitory effects of human salivary histatins and lysozyme on coaggregation between Porphyromonas gingivalis and Streptococcus mitis.

The effects of histatins on coaggregation between Porphyromonas gingivalis 381 and Streptococcus mitis ATCC 9811 were investigated by using a turbidimetric assay. The coaggregation activity was significantly inhibited by histatins 5 and 8 and strongly by lysozyme. Tritium-labeled histatin 8 bound to P. gingivalis cells but not to S. mitis cells.

Amino Acid Sequence↗
PubMed1991

Microcirculatory disturbance in indomethacin-induced intestinal ulcer.

Participation of microcirculatory disturbances, especially the role of 5-lipoxygenase products from neutrophils, was investigated in indomethacin (Indo)-induced ulcers of rat small intestine. After Indo treatment (20 mg/kg) in rats, small erosions appeared at 6 h and longitudinal ulcers developed 12 h later. At 6 and 12 h after Indo treatment, severe microcirculatory disturbances were observed under an intravital fluorescence microscope. Significant delay in the clearance and patchy pooling of injected fluorescein isothiocyanate-bovine serum albumin with sludge and stasis were observed in archade vessels of villi of Indo-treated rats. Increased numbers of sticking leukocytes were also detected along submucosal venules in these rats after the infusion of acridine orange. When regional venous blood was collected from the mesentery, a marked increase in neutrophil number and their increased production of oxygen-derived free radicals as determined by chemiluminescence assay were demonstrated at 6 h after Indo treatment. There was also a significant increase in myeloperoxidase activity of the intestinal mucosa at 6 and 12 h after Indo treatment, suggesting a significant neutrophil accumulation at this time. AA-861, a selective inhibitor of 5-lipoxygenase (80 mg/kg), attenuated these microcirculatory changes and neutrophil accumulation in the intestinal mucosa. AA-861 also significantly prevented the formation of intestinal ulcers induced by Indo. However, Indo-induced ulcer formation and leukocyte accumulation in submucosal venules were not attenuated by the treatment of Ono-1078, a potent antagonist of sulfidopeptide leukotrienes. From these observations, it is considered that microcirculatory disturbances, especially leukocyte accumulation and 5-lipoxygenase products, possibly leukotriene B4, may be involved in the development of Indo-induced intestinal ulcer.

Animals↗
PubMed1991

Analysis of idiopathic thrombocytopenic purpura patients with antiglycoprotein IIb/IIIa or Ib autoantibodies.

We analyzed the immunological characteristics of patients with idiopathic thrombocytopenic purpura (ITP) and antiglycoprotein (GP) IIb/IIIa or GPIb autoantibodies. Among 101 ITP patients, 32 had anti-GPIIb/IIIa and 19 had anti-GPIb autoantibodies. Thrombocytopenia was more severe in patients with anti-GPIb autoantibodies than in patients without these autoantibodies, whereas ITP patients with anti-GPIIb/IIIa autoantibodies did not develop severe thrombocytopenia. Patients with anti-GPIb autoantibodies showed significant increases of platelet-associated IgM and platelet-associated C3 in comparison with patients without the autoantibodies, despite there being no significant difference in the platelet-associated IgG levels. The lymphocyte subsets and the blastogenic response in patients with anti-GPIb autoantibodies were also significantly different from those in the patients without these autoantibodies. Furthermore, severe purpura and a poor response to prednisolone were far more common in the patients with anti-GPIb autoantibodies. Activation of the complement system and/or functional abnormalities of lymphocytes thus appear to be involved in the development of thrombocytopenia in ITP patients with anti-GPIb autoantibodies, and such antibodies may be associated with a particularly severe form of ITP.

Autoantibodies↗
PubMed1991

Pregnancy following transvaginal sonographic guided aspiration of endometrioma.

A 30-year-old infertile women with stage IV endometriosis was treated initially with endoscopic surgery, danazol and intrauterine insemination to no avail. Before starting ovulation induction for in vitro fertilization, transvaginal sonographic guided aspiration of endometrioma was performed. One month after the procedure the patient became pregnant and delivered a normal child at term.

Adult↗
PubMed1991

Synthesis and antitumor activity of 20(S)-camptothecin derivatives: A-ring modified and 7,10-disubstituted camptothecins.

20(S)-Camptothecin derivatives having nitro, amino, chloro, bromo, hydroxyl and methoxyl groups in the A-ring were synthesized. B-Ring hydrogenated camptothecin (2a) was converted into 10-hydroxycamptothecin (6e) by treatment with lead tetraacetate in trifluoroacetic acid. 10-Substituted derivatives (6) were obtained by a photoreaction of N-oxides (9). The cytotoxicity of the A-ring modified camptothecins was evaluated against KB cells in vitro and leukemia L1210 in mice. 7-Ethyl-10-hydroxycamptothecin (6i) was identified as a potential derivative for further modification.

Animals↗
PubMed1991

Orthoses of ventilative plastics.

Plastics are extensively used as a material for orthoses. However, one remaining problem is the ventilation of the orthosis. This is a real problem in countries such as Japan, where it is hot and humid especially in summer. The authors have invented a new orthosis "POROPLAST", which is made of mesh plastic sheets, combined in a cross-like weave. These orthoses provide good ventilation and are very comfortable to wear. They have been fitted to seventy-four cases with satisfactory results.

Dermatitis, Contact↗
PubMed1991

[Clinical evaluation of serum basic fetoprotein for prostatic cancer--comparative study with PAP, gamma-Sm and PSA].

The clinical significance of serum basic fetoprotein (BFP) in prostatic cancer was investigated together with serum prostatic acid phosphatase (PAP), gamma-seminoprotein (gamma-Sm) and prostate specific antigen (PA). Investigated in this study were 40 patients with prostatic cancer, ranging in age from 50 to 85 years (mean age: 69.5 years). According to clinical staging, 3 cases (7.5%) had a stage A disease, 10 cases (25.0%) a stage B disease, 7 cases (17.5%) a stage C disease, and 20 cases (50.0%) a stage D disease. The positive rates for serum BFP, PAP, gamma-Sm, and PSA were 60.0, 45.0, 63.6, and 68.4%, respectively, and these rates increased as the stage advanced. The above results suggest that BFP is the most useful marker of the four for monitoring prostatic cancer. In a combination assay of these four markers, 29 (87.9%) of 33 patients with prostatic cancer could be diagnosed by observing an elevated serum level in one of the markers. This suggests that a combination assay of BFP, PAP, gamma-Sm and PSA in patients with prostatic cancer is useful for diagnosis and monitoring of the disease.

Acid Phosphatase↗
PubMed1991

[A case of Garcin's syndrome caused by pachymeningitis secondary to otitis media, responsive to antibiotic therapy].

A 55-year-old woman noticed progressive hearing loss, earache and tinnitus in the left side in December 1988, followed by dysesthesia of the left face and hypogeusia. Those symptoms did not respond to the otological treatment of otitis media. In addition, the left eyelid ptosis, double vision and dysphagia appeared in May 1989. On admission, cranial nerves from III to XII were affected exclusively in the left side. The cell counts and the protein levels in the CSF were elevated. The MRI of the head showed hypertrophic dura mater at the left base of the skull covering the temporal lobe. No bone destruction was found in CT. The biopsy revealed the thickened dura mater with microabscess containing Langhans giant cells and lymphocytes. A diagnosis of pachymeningitis was made. After the therapy with antibiotics and then with prednisolone for several months, cranial nerve disturbances disappeared except hearing loss with decrease in cell counts and protein levels of the CSF. The follow-up MRI after one year showed decrease in thickness of dura mater. The MRI, particularly using enhancement with Gd-DTPA, was useful to make a diagnosis of hypertrophic pachymeningitis. It is suggested that the administration of antibiotics should be considered in the treatment of the pachymeningitis even if the causative agents were not identified.

Cefazolin↗
PubMed1991

The ultrastructure and distribution of fibrinogen, von Willebrand factor, and glycoprotein IIb/IIIa complex in platelet alpha-granules by cryo-ultramicrotomy.

Transformation upon mild stimulation and the ultrastructure of blood platelet alpha-granules were examined using cryo-ultramicrotomy. An ultrastructural study found not only round, but also elongated and drumstick-shaped alpha-granules and rod-like structures protruding from round alpha-granules. Some elongated alpha-granules showed distinctive cross-striations in the short axis with a periodicity in the order of 19-22 nm. Gold particle-labeled fibrinogen (Fbg) was observed on elongated alpha-granules having cross-striations. Electron-dense nucleoids were observed on some round alpha-granules. An electron-dense nucleoid, intermediate zone, and an electron-lucent matrix were noted in round alpha-granules by gold particle-labeled Fbg in the intermediate zone. Gold particle-labeled von Willebrand factor (vWF) was observed in alpha-granules except in nucleoid zones. Labeling for Fbg was also observed in rod-like structures protruding from round alpha-granules. Gold particle-labeled glycoprotein (GP)IIb/IIIa complex was observed on the inner face of alpha-granule membranes. A few elongated and drumstick-like alpha-granules were found on freshly fixed platelets. Elongated alpha-granules were only found in a small percentage of washed and collagen-stimulated platelets. Cryo-ultramicrotomy is useful for examination of the distribution of intracellular antigens.

Blood Platelets↗
PubMed1991

[Relationships between the amount of total protein in human milk, the volume of produced milk and food intake].

The concentration of total protein in human milk on the 5th or 6th day after full-term, normal delivery was measured in 145 women, and the amount of protein per 24 hours was calculated by multiplying protein concentration by 24-hour milk production for the same day. Relationships between the concentration and amount of protein, milk volumes and food intake during the latter period of the pregnancy were investigated. Quantification theory III statistical analysis was applied to analyze food intake patterns. While no individual food item was shown to be effective in improving quality and quantity of mother's milk, the results suggest that mothers who consumed meat, fish, food prepared with oil, seaweed, cow's milk and fruits frequently, and rarely used coffee; or mothers who consumed confectioneries and food prepared with oil frequently, rarely used coffee and alcohol beverages and disliked spices produced greater volumes of milk or milk containing a greater amount of protein.

Adult↗
PubMed1990

Serum basic fetoprotein in patients with renal cell carcinoma.

Serum basic fetoprotein (BFP), immunosuppressive acid protein (IAP), and tissue polypeptide antigen (TPA) levels were measured in patients with renal cell carcinoma. The positive rates of serum BFP, IAP, and TPA were 47%, 79%, and 42%, respectively. Serum levels and positive rates were found to be elevated according to the degree of disease advancement. Using a combined assay for the three markers, the positive rate for BFP, IAP, and TPA was 92%, and approximately 100% in Stages II, III, and IV of the disease. Therefore, the combined marker assay improved the diagnosis of renal cell carcinoma. In curative resection patients, the percent of patients whose serum BFP levels returned to normal 1 week after the operation was 85. This was higher than the IAP or TPA levels (18% and 67%, respectively). Moreover, in inoperable patients, serum BFP levels showed a better correlation with the clinical course than serum IAP or TPA levels. Serum BFP is useful for monitoring patients with renal cell carcinoma who have an elevated BFP value.

Adult↗