Biomedical subjects

H Azuma

Publications and source records attributed to H Azuma.

At least 145 records · Page 8Linked to original sources

PubMed1995

Intraspecific variation of Taenia taeniaeformis as determined by various criteria.

The intraspecific variation of four laboratory-reared isolates of Taenia taeniaformis the SRN and KRN isolates from Norway rats, Rattus norvegicus, captured in Japan and Malaysia, respectively; the BMM isolated from a house mouse, Mus musculus, captured in Belgium; and the ACR isolate from a gray red-backed vole, Clethrionomys rufocanus bedfordiae, captured in Japan was examined by various criteria. Eggs of each of the four isolates were orally inoculated into several species of intermediate host. They were most infective to the rodent species from which the original metacestode of each isolate had been isolated in the field, and only the ACR isolate was infective to the gray red-backed vole. Although little difference was found between the SRN, KRN, and BMM isolates by the other criteria, including the morphology of rostellar hooks, the protein composition of the metacestode, and restriction endonuclease analysis of DNA, the ACR isolate was clearly different from the others. It was considered that the ACR isolate was independent as a strain distinct from the other three isolates.

Animals↗

PubMed1995

Acute transverse myelitis caused by ECHO virus type 18 infection.

UNLABELLED: A 14-year-old boy developed acute quadriplegia, associated with sensory impairment and bowel and urinary dysfunction. MRI of the cervical cord showed diffuse increased signal intensity on T2-weighted images with gadolinium-diethylenetriamine penta-acetic acid enhancement. Based on the clinical presentation and MRI findings, the diagnosis of acute transverse myelitis was made. Enterovirus RNA was amplified from CSF by the reverse transcriptase-polymerase chain reaction. Serum neutralizing antibody to ECHO virus type 18 rose from 1/4 on admission to 1/16 2 months later. CONCLUSION: This is the first reported case of acute transverse myelitis caused by ECHO virus type 18 infection.

Acute Disease↗

PubMed1995

Binding of lymphocytes to acutely rejecting rat kidney allografts in vitro is guided by events in the graft itself rather than by sensitization of host lymphocytes.

Circulating host lymphocytes recognize, bind to, become activated by, and infiltrate engrafted allogeneic tissues. The mechanisms responsible for these early events which lead to acute immunological rejection have not been precisely defined. We have examined sequentially in vitro lymphocyte binding patterns in a kidney transplant model of acute rejection in rats and their relationship to the expression of two representative adhesion molecules, ICAM-1 and LFA-1. The extent of binding of naive, or allosensitized recipient strain LNL or PBL, or donor strain or third party cells to frozen sections of kidney allografts was not significantly different; adherence was dependent upon whether the graft was an allograft or an isograft. The pattern of lymphocyte adherence to various allograft compartments was distinct and varied with time. Within 3 days after transplantation only a few cells had bound to the frozen tissues, preferentially to vascular endothelium. By days 5 and 7, increasing numbers of cells bound primarily to tubules, as did the few cells adhering to isografts. Immunohistologically, ICAM-1 expression increased progressively during acute rejection, first on vascular endothelium, later on tubules. LFA-1+ infiltrating cells peaked more quickly. Lymphocyte binding could be inhibited (approx. 40%) by monoclonal antibodies directed against LFA-1 and ICAM-1. The results indicate that in vitro lymphocyte binding to acutely rejecting kidney transplants is directed by the allogenicity of the graft itself via upregulation of adhesion molecules rather than sensitization of the host cells.

Acute Disease↗

PubMed1995

The effects of endothelin-1 on isolated bovine ciliary muscles.

The effects of endothelin-1 on bovine ciliary muscle were investigated in vitro using muscle strips prepared in two different directions (longitudinal and circular). Fifty-two bovine ciliary muscle strips (4 x 6 mm) were prepared. Chemicals were added to both types of strips suspended in an organ chamber, and their changes in isometric tension were recorded. The concentration-response relationship of endothelin-1 (n = 20), the magnitudes of contractions caused by endothelin-1 and carbachol (n = 12), and the effects of an endothelin receptor subtype A antagonist BQ123 (n = 4) and an endothelin receptor subtype B agonist IRL1620 (n = 4) were studied. The cumulative addition of endothelin-1 caused relaxation at low concentrations (10(-11) and 10(-10) M), while it caused contraction of the ciliary muscles at high concentrations (10(-9), 10(-8) and 3 x 10(-8) M). The magnitude of the contraction caused by 10(-8) M endothelin-1 was about 30% in the longitudinal muscle strips and 29% in the circular muscle strips, relative to the contraction caused by 10(-5) M carbachol, a muscarinic agonist. The contractile response caused by 10(-8) M endothelin-1 was abolished and converted to relaxation by pretreatment with BQ123, a selective endothelin receptor subtype A antagonist. Single addition of IRL1620, a selective endothelin receptor subtype B agonist, caused only relaxation. These results suggest that, endothelin-1 causes not only contraction at high concentrations, but also relaxation at low concentrations in bovine ciliary muscle. Also, it suggested that the relaxation is mediated by endothelin receptor subtype B, whereas the contraction is mediated by endothelin receptor subtype A.

Animals↗

PubMed1995

Safety and pharmacokinetics of iotrolan in hysterosalpingography. Retention and irritability compared with Lipiodol.

RATIONALE AND OBJECTIVES: The authors compared the safety and pharmacokinetics of Iotrolan (water-soluble) in hysterosalpingography (HSG) with those of Lipiodol (oil-soluble). METHODS: Iotrolan and Lipiodol were administered intraperitoneally at doses of 100 mg iodine/kg to female rabbits. Retention in the body was investigated by x-ray imaging, plasma kinetics, and urinary and fecal excretion. Irritability in the abdomen was investigated by histologic examination. RESULTS: Iotrolan was entirely excreted into the urine within 2 days after administration. Conversely, Lipiodol was excreted into the urine, had a half-life of 50 days, and was retained for more than 21 days in the abdomen. Iotrolan induced no inflammatory reaction in the abdomen, whereas Lipiodol induced a marked abdominal inflammatory reaction, including granuloma formation. Iotrolan had no effect on iodine concentration in the thyroid; Lipiodol increased iodine concentration significantly. CONCLUSIONS: Iotrolan, which is a water-soluble and nonionic dimeric contrast medium, has potential greater safety for use in HSG than Lipiodol.

Abdomen↗

PubMed1995

Different localization of ETA and ETB receptors in the hyperplastic vascular wall.

We investigated which subtypes of endothelin-1 (ET-1) receptors are involved in the pathogenesis of angioplasty-induced lesion formation in the rabbit carotid artery. Four weeks after removing endothelial cells (EC), we noted a marked intimal hyperplasia. The Bmax values for [125I]ET-1 and [125I]IRL1620 (an agonist for the ETB receptors) bindings were greater in the hyperplastic artery, without changes in Kd values. [125I]ET-1 binding was completely inhibited by unlabeled ET-1 and Ro 46-2005, a mixed-type antagonist for the ETA and ETB receptors, but partially by BQ123, a selective antagonist for ETA receptors, and IRL1620. The [125I]ET-1 binding sites not inhibited with BQ123 were significantly increased in the hyperplastic artery. The binding study suggested the presence of non-ETA/non-ETB receptors. The rank order of the increasing ratio in the density of receptors was ETB > putative non-ETA/non-ETB > total ET-1 receptors > ETA. The histochemical experiments with biotinylated ET-1 at lysine-9 side chain alone or in combination with unlabeled ET-1, BQ123, Ro 46-2005, or IRL1620, showed the ETA receptors to be localized mainly in the media, whereas the ETB receptors localized mainly in the neointima. These results suggest that the increased ET-1 receptors, especially ETB and/or putative non-ETA/non-ETB, are closely related to the occurrence of the intimal hyperplasia after endothelial removal.

Analysis of Variance↗

PubMed1995

Accelerated endothelial regeneration and intimal hyperplasia following a repeated denudation of rabbit carotid arteries: morphological and immunohistochemical studies.

1. We compared endothelial regeneration and intimal thickening after endothelial denudation between normal and sclerotic carotid arteries (CA). Endothelial denudation of the right CA of rabbits formed intimal thickening covered with regenerated endothelial cells (EC) in 6 weeks, which was considered as the sclerosis model. Both CA were then denuded. Morphological and immunohistochemical studies using antibodies for proliferating cell nuclear antigen (PCNA), von Willebrand factor and macrophages were performed. 2. Regeneration of EC were observed 24 h after denudation on both CA, but completed earlier in the double-denuded right CA. The density of EC in both CA increased after regeneration and gradually decreased afterwards. 3. After a single denudation on the left CA, PCNA-positive cells clearly appeared in 24 h, markedly increased in 72 h both in the intima and media, then greatly decreased in 4 and 6 weeks. 4. After a double denudation of the right CA, enhancement of the intimal hyperplasia was observed. PCNA-positive cells markedly increased in 1 week and remained significantly increased in 6 weeks both in the intima and the media. 5. We concluded from these results that the repeated endothelial denudation caused more sustained proliferation of smooth muscle cells which led to an enhancement of the intimal hyperplasia.

Analysis of Variance↗

PubMed1995

Role of endothelium in the human uterine arteries during normal menstrual cycle.

1. The present experiments were designed to investigate the role of endothelium in the human uterine arteries during the normal menstrual cycle. 2. Acetylcholine (ACh) produced a concentration-dependent relaxation response during the higher level of plasma 17 beta-oestradiol (E2) (follicular and luteal phases, E2 = 131.9 +/- 15.9 pg ml-1, n = 13; group I). However, the agent did not produce a definite relaxation, but produced a slight contraction during the ovulatory and menstruation phases (E2 = 19.8 +/- 2.9 pg mg-1, n = 5; group II). During the follicular and luteal phases (E2 = 181.1 +/- 9.0 pg ml-1, n = 6), ACh produced a slight contraction, but not relaxation in 6 cases (group III). Relaxation in response to A23187 in group II was not different from that in group I, while it was significantly (P < 0.05 and P < 0.005) reduced in group III. Sodium nitroprusside (SNP)-induced relaxation was similar in the three groups. 3. Correlation between the maximum response to ACh and the plasma E2 was highly significant (gamma = 0.8142, P < 0.001) in 18 cases of groups I and II, but not in all 24 cases including group III (gamma = 0.1183, NS). 4. Relaxations in response to ACh in group I or A23187 in all groups were abolished after removal of the endothelium. In group I, ACh- and A23187-induced relaxations were greatly inhibited by methylene blue or NG-nitro-L-arginine (L-NOARG) and partially inhibited by indomethacin. None of these treatments except for methylene blue modified the SNP-induced relaxation, which was significantly inhibited by methylene blue.5. The A23187-induced relaxation was hardly affected by methylene blue or L-NOARG in group III,but was partially inhibited by these agents in group II. The effect of indomethacin in inhibiting the A23187 induced-relaxation was most potent (58.9%) in group III and least (16.9%) in group I.6. There were no histological changes in 14 cases out of 18 (groups I and II), but very slight intimal thickening was observed in 4 cases in group I. On the other hand, severe intimal thickening was observed in all 6 cases in group III.7. These results indicate that, in human uterine artery strips, ACh and A23187 cause endothelium dependent relaxations, which are mediated mainly through EDRF/NO in group I, mainly prostacyclin(PGI2) in group III, or both in group II. It is suggested that lack of the production/release of EDRF/NO and/or of interaction between EDRF/NO and PGI2 might play a role in the formation of intimal thickening in human uterine arteries.

Acetylcholine↗

PubMed1995

Accumulation of endogenous inhibitors for nitric oxide synthesis and decreased content of L-arginine in regenerated endothelial cells.

1. We examined regeneration of endothelial cells (ECs), neointima formation, decreased endothelium-dependent relaxation (EDR) and changes in the contents of L-arginine, NG-monomethyl-L-arginine (L-NMMA), asymmetrical NG, NG-dimethylarginine (ADMA) and symmetrical NG,NG-dimethylarginine (SDMA) in the regenerated ECs, 6 weeks after balloon denudation of the rabbit carotid artery. 2. Regeneration of ECs was completed in 6 weeks and a significant neointima formation accompanied by the decreased EDR was observed. 3. L-NMMA and ADMA contents in the regenerated ECs (23.5 +/- 4.3 and 21.2 +/- 2.0 pmol mg-1 DNA, respectively) were significantly (P < 0.05 and P < 0.01) higher than those in the control ECs (8.8 +/- 3.0 and 7.4 +/- 1.9 pmol mg-1 DNA, respectively), whereas L-arginine was significantly (P < 0.005) decreased in the regenerated ECs (31,470 +/- 1,050 pmol mg-1 DNA) as compared to that in the control ECs (47,870 +/- 1,890 pmol mg-1 DNA). SDMA content was below the assay limits. 4. L-NMMA and ADMA, but not SDMA, inhibited the EDR induced by acetylcholine in a concentration-dependent manner. The inhibition with L-NMMA and ADMA was prevented by an addition of L-arginine, but not by D-arginine. 5. These results suggest that the accumulation of endogenous inhibitors for nitric oxide synthesis and decreased L-arginine content are associated with decreased NO production/release from regenerated ECs and neointima formation.

Acetylcholine↗

PubMed1995

Antegrade and retrograde fluid transport through the vas deferens.

Intraluminal pressure of the seminal tract at seminal emission from the ejaculatory duct and the mode of transport of cauda epididymal contents were investigated to explore the mechanism of sperm transport. Direct electrical stimulation of any site of the cauda epididymis and vas deferens, which generated nerve-transmitted muscle contraction, caused elevation of the intraluminal pressure only at the cauda epididymis, whereas stimulation of the testis, caput, and corpus epididymis caused no response. The dye instilled in the cauda was emitted into the urethra during the stimulation. Shortly after discontinuation of the stimulation, retrograde movement of residual dye in the vas resulted in its ultimate reentry into the cauda epididymis. Significant decrease of the muscle tonus just after contraction was observed at the cauda. Distension of the wall of the vas generated elevation of the intraluminal pressure only at the site distended. The above results indicate the presence of rapid antegrade and retrograde movement of the sperm and the crucial role of the cauda epididymis on the sperm transport.

Animals↗

PubMed1995

Immunohistochemical detection of Ki-67 in replicative smooth muscle cells of rabbit carotid arteries after balloon denudation.

BACKGROUND AND PURPOSE: Ki-67 immunohistochemistry has been shown to be useful for paraffin sections from human species after wet heating. We applied Ki-67 immunohistochemistry to rabbit arteries after balloon denudation and compared the results with proliferating cell nuclear antigen (PCNA) immunohistochemistry. METHODS: Monoclonal antibodies MIB-1 for Ki-67 and PC-10 for PCNA were used to detect replicative smooth muscle cells in rabbit carotid arteries during a period of 4 weeks after balloon endothelial denudation. RESULTS: We demonstrated clear immunoreactivities for Ki-67 in paraffin sections of rabbit arteries after hydrated autoclaving. Ki-67-positive smooth muscle cells appeared throughout the thickened intima 1 week after endothelial denudation. At 2 weeks, Ki-67-positive cells were confined to the surface layer of the intima. PCNA-positive cells appeared in almost the same location by 2 weeks after endothelial denudation but were significantly greater in number than Ki-67-positive cells. PCNA-positive cells remained in the surface layer of the intima 4 weeks after endothelial denudation, while Ki-67-positive cells had almost disappeared from the intima. CONCLUSIONS: Our results indicate that Ki-67 immunohistochemistry using MIB-1 monoclonal antibody provides a powerful tool, even in rabbit species, for the detection of replicative smooth muscle cells during the repair of arterial injury and that it detects replicative cells more accurately than PCNA immunohistochemistry.

Animals↗

PubMed1995

[Isolated iliac artery aneurysms associated with disseminated intravascular coagulation (DIC)].

An 84-year-old man was referred to our hospital on December 3, 1993, because of excessive bleeding after tooth extraction. Coagulation studies revealed thrombocytopenia (2.2 x 10(4)/microliter), increased serum levels of FDP-E (3172 ng/ml) and D dimer (42.6 micrograms/ml), and increased plasma levels of thrombin-atithrombin III complex (48.0 ng/ml) and plasmin-alpha 2-plasmin inhibitor complex (6.8 micrograms/ml). Computed tomography showed bilateral common iliac artery aneurysms. A diagnosis of DIC due to bilateral common iliac artery aneurysms was made. Heparin (10,000 U/day) administered to treat DIC resulted in good control, and operative repair of the aneurysms was successful. This is the second reported case of isolated iliac artery aneurysms associated with DIC.

Aged↗

PubMed1995

The nerve endings of the acetabular labrum.

The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzuki's silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.

Acetabulum↗

PubMed1995

Congenital deficiency of histidine-rich glycoprotein: failure to identify abnormalities in routine laboratory assays of hemostatic function, immunologic function, and trace elements.

Histidine-rich glycoprotein (HRGP) has many biologic activities, but its physiologic function is still unclear. To show the physiologic function of HRGP, we studied five patients with congenital HRGP deficiency. Hemostatic screening tests, activities of natural anticoagulants and fibrinolytic proteins, markers of thrombin and plasmin generation, plasma levels of platelet-specific proteins, thrombin times with various concentrations of bovine thrombin, prolongation of thrombin time after addition of heparin or demartan sulfate, and contact activation of blood coagulation were normal or nearly normal in these patients. Serum concentrations of immunoglobulin, functional activity of the classical and the alternative pathway of complement, lymphocyte subsets, and serum concentrations of soluble interleukin-2 receptor were approximately normal in all patients, and serum concentrations of copper and zinc were completely normal. These results suggest that the physiologic functions of HRGP are limited when compared with its biologic activities. However, because the patients examined had plasma HRGP levels of 20% to 35% of normal, it is possible that 20% of normal HRGP level is sufficient for its physiologic functions.

Antigens, CD↗

PubMed1995