Biomedical subjects

H Yokoi

Publications and source records attributed to H Yokoi.

At least 91 records · Page 5Linked to original sources

PubMed1997

Remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy.

BACKGROUND: Recently, long-term constriction of the vessel has been suggested as an alternative mechanism of restenosis after coronary angioplasty. METHODS AND RESULTS: To understand remodeling of human coronary arteries undergoing coronary angioplasty or atherectomy, serial intravascular ultrasonographic examinations were performed at preintervention and postintervention examinations and at 24 hours, 1 month, and 6 months. Complete serial data were obtained in 61 lesions (balloon angioplasty, 35 lesions; directional atherectomy, 26 lesions). Lumen area improved from 6.81+/-2.24 mm2 after intervention to 8.22+/-2.79 mm2 at 1 month (P=.0001) and decreased to 4.88+/-2.86 mm2 at 6 months (P=.0001). Vessel area enlarged from 17.32+/-5.35 mm2 after intervention to 19.39+/-5.33 mm2 at 1 month (P=.0001) and decreased to 16.33+/-5.54 mm2 at 6 months (P=.0001). Plaque+media area increased significantly from postintervention examination to 24 hours (10.51+/-4.38 versus 10.96+/-4.49 mm2, P=.0008) and from 24 hours to 6 months (10.96+/-4.49 versus 11.45+/-4.45 mm2, P=.03). Changes in lumen area in each study interval correlated more closely with changes in vessel area than with changes in plaque+media area. Restenotic lesions compared with nonrestenotic lesions had a greater decrease in the vessel area between 1 month and 6 months (-4.33+/-2.73 versus -2.49+/-2.15 mm2, P=.006) and greater increase in the plaque+media area both within 24 hours (0.84+/-1.22 versus 0.27+/-0.38 mm2, P=.04) and between 24 hours and 6 months (1.19+/-2.19 versus 0.18+/-1.46 mm2, P=.04). CONCLUSIONS; Remodeling after coronary angioplasty or atherectomy was characterized by early adaptive enlargement and late constriction of the vessel.

Aged↗

PubMed1997

Relationship between HLA-C locus and restenosis after coronary artery balloon angioplasty.

OBJECTIVES: To determine the relationship between human leukocyte antigen (HLA) loci and restenosis after percutaneous transluminal coronary angioplasty (PTCA). DESIGN AND SETTING: Cross-sectional study in patients treated by PTCA at Juntendo University Hospital, Tokyo, Japan. PATIENTS: A total of 65 patients (58 males and 7 females) with coronary artery stenosis who were consecutively selected between October 1994 and June 1995. MAIN OUTCOME MEASURES: Significant relationships between the restenosis and the HLA-Cw1. RESULTS: Among HLA-C locus, Cw1 was negatively related to restenosis (multivariate adjusted odds ratio, 0.19; 95% confidence interval, 0.06-0.63; P=.007). CONCLUSIONS: In HLA typing, Cw1 may be a useful marker for the prediction of restenosis after PTCA.

Aged↗

PubMed1997

Expression of a novel isoform of Vav, Vav-T, containing a single Src homology 3 domain in murine testicular germ cells.

Vav is a signal transducing molecule containing C-terminal Src homology 3 (SH3)-SH2-SH3 domains, and has been thought to be expressed exclusively in hematopoietic and trophoblastic cells. By Northern blot analysis, vav transcripts of unique sizes, 4.8 kb and 1.0 kb, were detected in the testis among various tissues examined. From a mouse spermatocyte cDNA library, a novel isoform of vav (vav-T) was cloned, which corresponded to a part of the 4.8 kb transcript. Vav-T had an alternative 5' sequence up to the middle of SH2-coding region, and encoded 163 amino acids with a single SH3 domain. Northern blot analysis of fractionated testicular cells and in situ hybridization histochemistry demonstrated that vav-T transcripts were expressed in the differentiating germ cells, especially spermatocytes. A 24 kD protein was detected by anti-Vav antibodies in the testis, but not in the spleen or bone marrow. Transcripts of heterogeneous nuclear ribonucleoprotein K, known to associate with the most C-terminal SH3 domain of Vav, were also detected in the differentiating male germ cells. These results demonstrate expression of previously nondescribed Vav-isoform in the testicular germ cells, and suggest that it interacts with RNA-binding proteins and plays an important role in spermatogenesis.

Amino Acid Sequence↗

PubMed1997

NMDA receptor clustering in rat prefrontal cortex revealed by in vitro calcium macroimaging.

Living coronal brain slices were prepared from the rat prefrontal cortex (pFC) to determine the topographical distribution of the functional calcium-permeable N-methyl-D-aspartate (NMDA) receptor in vitro using calcium macroimage analysis with fura-2 AM. NMDA (0.25, 0.5, 1 or 2 x 10(-4) M for 30 s) bath application showed a dose-dependent [Ca2+]i increase from the steady-state level in several portions selected from the whole hemisphere slice. This regional response was suppressed by D-2-amino-5-phosphonopentanoic acid (10(-4)M) and reinforced by glycine coperfusion (5 x 10(-6) M). Image analysis showed that the cluster responsive to NMDA lay locally on the medial or lateral pFC even in the presence of tetrodotoxin.

Animals↗

PubMed1997

Initial experience with the Cordis stent: analysis of serial angiographic follow-up.

To evaluate the efficacy of the more flexible Cordis stent, a prospective angiographic follow-up study was performed. Implantation of the Cordis stent was attempted in 99 consecutive patients with 103 native coronary lesions from January 1994 to July 1995. Clinical success, defined as final diameter stenosis of < 50% without death, bypass surgery, or Q-wave myocardial infarction, was achieved in 88% of the patients. There were no in-hospital deaths. In-hospital subacute stent occlusion occurred in only one case. Follow-up angiograms were obtained in 86 (95%) eligible lesions. The minimal luminal diameter improved from 1.03 +/- 0.31 to 2.82 +/- 0.31 mm, but started to decrease at 1 mon (2.57 +/- 0.24 mm), and continued to decrease throughout the 6 mon (2.00 +/- 0.61 mm), the biggest reduction being between 1 and 3 mon (-0.57 +/- 0.50 mm). Angiographic restenosis (stenosis > or = 50%) occurred in 23% of the lesions; a revascularization procedure of the target lesion was required in 12% of the patients. Multivariate analysis identified age, diabetes mellitus, and preprocedural reference diameter to be predictors of angiographic restenosis. In conclusion, the Cordis stent can be implanted successfully with a low complication rate and a clinical outcome at least comparable to other stent studies.

Adult↗

PubMed1997

Prevention of experimental autoimmune uveoretinitis by monoclonal antibody to interleukin-12.

Experimental autoimmune uveoretinitis (EAU) induced by immunization with interphotoreceptor retinoid-binding protein (IRBP), a retinal self antigen, has been regarded to be a typical T helper type 1 (Th1)-mediated inflammatory disease. In this study, we examined the effect of a neutralizing monoclonal antibody (mAb) to interleukin-12 (IL-12), which has been known to play a critical role in the Th1 differentiation, on the development of EAU. While 9 of 13 control mice developed EAU by the immunization with IRBP, none of 12 mice developed EAU when given anti-IL-12 mAb 1 day before immunization. These mice did not develop EAU even after a rechallenge with IRBP on day 30, indicating that a protective mechanism had been established by the anti-IL-12 treatment. The proliferative response of splenocytes to IRBP in vitro was not significantly impaired, but the production of IL-2 and IFN-gamma was greatly reduced by the anti-IL-12 treatment. Moreover, production of IL-5 and expression of IL-4 mRNA were increased by the anti-IL-12 treatment. Consistently, IgG2a anti-IRBP serum antibodies were decreased and IgG1 were increased. Administration of a neutralizing anti-IL-4 mAb at the time of IRBP rechallenge reversed the protection established by the anti-IL-12 treatment at the primary immunization. These results indicate that the anti-IL-12 treatment at the IRBP priming not only prevented the development of pathogenic Th1 cells, but also induced suppressive Th2 cells that protect the animals from further challenge with the same antigen.

Animals↗

PubMed1997

Decreased glucose effectiveness but not insulin resistance in glucose-tolerant offspring of Japanese non-insulin-dependent diabetic patients: a minimal-model analysis.

The aim of the study was to estimate insulin sensitivity (SI), insulin secretion, and glucose effectiveness (SG) in 10 subjects with normal glucose tolerance (eight men and two women) with a family history of non-insulin-dependent diabetes mellitus (NIDDM offspring). Ten glucose-tolerant subjects (eight men and two women) without a family history of NIDDM served as control subjects. All subjects were Japanese. They underwent a modified frequently sampled intravenous glucose tolerance test (FSIGT): glucose (300 mg/kg body weight) was administered, and insulin (20 mU/kg over 5 minutes) was infused from 20 to 25 minutes after glucose. SI and SG were estimated by Bergman's minimal-model method. No significant difference was observed in body mass index (22.6 +/- 1.5 v 21.5 +/- 0.6 kg/m2) and fasting glucose (5.1 +/- 0.1 v 5.2 +/- 0.1 mol/L) and insulin (40.7 +/- 6.3 v 42.6 +/- 6.7 pmol/L). SI was not different between the two groups (0.83 +/- 0.11 v 0.94 +/- 0.15 x 10(-1).min-1.pmol/ L-1, P > .05). The acute insulin response to glucose (AIRglucose) estimated by intravenous glucose tolerance testing was significantly lower in the offspring than in the normal controls (2,139 +/- 265 v 3,438 +/- 318 pmol/L.min, P < .05). The glucose disappearance rate (KG) and SG were significantly diminished in the offspring versus normal controls (KG, 1.50 +/- 0.22 v 2.10 +/- 0.15 min-1, P < .05; SG, 0.016 +/- 0.003 v 0.023 +/- 0.002 min-1, P < .05). Thus, glucose-tolerant Japanese NIDDM offspring with normal insulin sensitivity are characterized by a reduced AIRglucose and diminished SG. This is the first report that glucose resistance but not insulin resistance already exists in glucose-tolerant Japanese NIDDM offspring.

Blood Glucose↗

PubMed1997

Effectiveness of an antioxidant in preventing restenosis after percutaneous transluminal coronary angioplasty: the Probucol Angioplasty Restenosis Trial.

OBJECTIVES: The Probucol Angioplasty Restenosis Trial was a prospective, randomized, controlled study that investigated the effectiveness of probucol therapy in reducing the rate of restenosis after percutaneous transluminal coronary angioplasty (PTCA). BACKGROUND: Antioxidants have an inhibitory effect on smooth muscle cell growth in experiments in vitro and in vivo, which suggests a possible pharmacologic effect on restenosis after PTCA. METHODS: One hundred one patients were randomly assigned to receive 1,000 mg/day of probucol or control (no lipid-lowering) therapy 4 weeks before PTCA. After 4 weeks of premedication, both groups underwent PTCA. Probucol was continued until follow-up angiography 24 weeks after PTCA. Angiographic results were analyzed at a core laboratory by quantitative coronary angiography. RESULTS: Dilation was successful in 46 of 50 patients in the probucol group and 45 of 51 in the control group. At follow-up angiography 24 weeks after angioplasty, angiographic restenosis occurred in 9 (23%) of 40 patients in the probucol group and 22 (58%) of 38 in the control group (p = 0.001). Minimal lumen diameter was 1.49 +/- 0.75 mm (mean +/- SD) in the probucol group and 1.13 +/- 0.65 mm in the control group (p = 0.02). Percent diameter stenosis at follow-up angiography in the probucol group was significantly lower than that in the control group (43.9% vs. 56.4%, p = 0.009). The late loss was 0.37 +/- 0.69 mm in the probucol group and 0.60 +/- 0.62 mm in the control group (p = 0.13). The loss/gain ratio was 0.32 +/- 0.74 in the probucol group and 0.56 +/- 0.81 in the control group (p = 0.059). Net gain was greater in the probucol group than in the control group (0.77 +/- 0.70 vs. 0.48 +/- 0.59 mm, p = 0.053). CONCLUSIONS: Probucol administered beginning 4 weeks before PTCA appears to reduce restenosis rates.

Aged↗

PubMed1997

Molecular cloning and characterization of a cDNA for plastidic copper/zinc-superoxide dismutase in rice (Oryza sativa L.).

A cDNA encoding plastidic Cu/Zn-SOD was isolated from rice. The deduced amino acid sequence included a transit peptide in the amino-terminal residues and showed a high similarity to those of plastidic Cu/Zn-SODs from other plants. The level of expression of this transcript was high in green leaves and differed from that of other rice SOD mRNAs in various tissues.

Amino Acid Sequence↗

PubMed1997

Ovulation defect and its restoration by bone marrow transplantation in osteopetrotic mutant mice of Mitf(mi)/Mitf(mi) genotype.

Mutation within the Mitf gene causes, in microphthalmic Mitf(mi)/Mitf(mi) (mi/mi) mice, multiple defects, including white coat color and functional defects in macrophages and osteoclasts. Our previous mating experiments have demonstrated that the mi mutation reduces the numbers of newborns and induces uterine inversion at delivery. The present study was designed to determine the causes of these pregnancy defects. The histology and number of F4/80-positive macrophages were not different between the ovaries of 23-day-old mi/mi and +/+ mice given eCG 48 h earlier. When ovulation was induced in these mice by hCG, the number of ovulated ova was significantly smaller in mi/mi mice than in wild-type (+/+) mice (p < 0.05). When bone marrow cells from +/+ mice were transplanted i.p. into 42 mi/mi female newborns, successful transplantation was observed in 16 of them at 20 days after birth. In one of these, the upper incisors had erupted. The mean number of tubal ova in mi/mi mice significantly increased after transplantation (p < 0.05) and was almost equal to that of +/+ mice. No uterine inversion occurred at 6 deliveries in 5 mi/mi females after bone marrow transplantation, while it occurred at 4 of 5 deliveries in mi/mi females during the same observation period (p < 0.05). These results indicate that bone marrow-derived cells, defective in mi/mi mice, are necessary for normal ovulation and delivery; the findings are consistent with the notion that macrophages play major roles in ovulation.

Animals↗

PubMed1997

Long-term survey on intestinal nematode and cestode infections in stray puppies Ibaraki Prefecture.

We conducted the survey on intestinal nematode, mainly Toxocara canis, and cestode infections in stray puppies aged less than 5 months in Ibaraki Prefecture for 8 years from 1988 to 1995. The rate of T. canis infection stayed almost unchanged for the 8 years and ranged from 72.2 to 85.4%. Of the total 916 dogs, 732 (79.9%) harboured with T. canis. The average rates of other helminthic infections showed 24.6 (Diphylidium caninum), 2.5 (Trichuris vulpis), 1.2 (Ancylostoma caninum) and 0.7% (Spirometra erinaceieuropaei) respectively.

Animals↗

PubMed1997

Clinicopathologic factors influencing the long-term prognosis following hepatic resection for large hepatocellular carcinoma more than 10 cm in diameter.

We resected 158 cases of hepatocellular carcinoma (HCC), including 20 (12.6%) cases of large HCC. These 20 cases were divided into group 1 (curative resection, n = 9) and group 2 (noncurative resection, n = 11). The clinicopathologic features and long-term survival of the cases were evaluated. In groups 1 and 2, portal vein invasion (Vp+) was noted in 44.4% and 63.3%, intrahepatic metastasis (IM+) in 77.8% and 100%, absence of a fibrous capsule (Fc-) in 55.6% and 63.6%, and stage III or IV in 77.8% and 100%, respectively. The DNA ploidy pattern was aneuploid in 44.4% of group 1 and 100% of group 2. In group 1, the 1-, 3-, and 5-year cumulative survival rates were 75%, 62.5%, and 62.5%, respectively (the longest survivor is alive after 11 years 1 month). Five cases survived more than 3 years in group 1, and all were Vp(-) and nonaneuploid. On the other hand, in group 2, the 1-year survival rate was only 33.3%; none survived more than 2 years. These results suggest that even patients with large HCC have a favorable long-term prognosis if their clinicopathologic factors are Vp(-) and nonaneuploid, and if curative resection can be performed.

Adult↗

PubMed1997

[Percutaneous transluminal coronary angioplasty in patients with multivessel coronary disease: does complete revascularization improve the long-term survival?].

The influence of complete revascularization on long-term outcome of patients with multivessel coronary artery disease undergoing percutaneous transluminal coronary angioplasty (PTCA) was determined by analysis of 10-year survival in 167 consecutive patients treated at Juntendo University Hospital during 1984-1993. Forty-nine patients were completely revascularized and 118 had incomplete revascularization according to the anatomical classification. Among patients with anatomically incomplete revascularization, 56 were categorized as functionally adequate revascularization and 62 as functionally inadequate revascularization according to Faxon's criteria. Baseline characteristics showed incompletely revascularized patients had a higher incidence of prior myocardial infarction triple-vessel disease and/or chronic total occlusion in at least one lesion. The 10-year survival was slightly better in patients with complete (100%) than in those with incomplete revascularization (79%), but not statistically significant (p = 0.089). Event-free survival was not significantly different between the two groups. However, the need for coronary artery bypass surgery was higher in the incomplete revascularization group than that in the complete revascularization group (100% vs 81%, p = 0.013). The influence of the degree of functional revascularization on outcome was not clear in the present study. Long-term survival appeared to be better in patients with complete revascularization than that in patients with incomplete revascularization, but even in the latter, coronary artery bypass grafting in the later period could improve outcome. The effect of functional revascularization status should be further investigated in a larger population.

Angioplasty, Balloon, Coronary↗

PubMed1997

[Inhibition of experimental autoimmune uveoretinitis by transforming growth factor-beta 1 in B10. A mice].

Experimental autoimmune uveoretinitis (EAU) in mice, an organ specific autoimmune disease, has been investigated as an animal model for human endogenous uveitis. In this study, we report on the immunosuppressive effect of transforming growth factor-beta 1 (TGF-beta 1) on the development of EAU in mice. Inhibition by TGF-beta 1 of proliferation of interphotoreceptor retinoid-binding protein (IRBP)-specific T cell lines in B10.A mice against IRBP antigen was dose-dependent. However, when spleen cells used as the antigen presenting cell were first cultured with TGF-beta 1, this anti-proliferation effect was abolished. When IRBP-immunized mice were injected intraperitoneally with TGF-beta 1, dose-dependent suppression of EAU was obtained. The proliferation response of lymph node cells from TGF-beta 1 injected mice with IRBP-induced EAU was suppressed compared with phosphate buffered saline (PBS)-injected mice. These findings suggest that TGF-beta 1 may be a cytokine that plays a role in suppressing IRBP induced EAU in mice.

Animals↗

PubMed1997

Morphological studies on middle ear barotrauma in guinea pigs.

Experimental middle ear barotrauma was studied morphologically. White guinea pigs were placed in an experimental hyperbaric chamber, and middle ear barotrauma was created by increasing the pressure in the hyperbaric chamber from 1 atmosphere absolute (ATA) to 2 ATA using pure oxygen, maintaining the pressure at 2 ATA for 10 minutes, then again reducing the pressure to 1 ATA. Selected experimental animals were decapitated immediately after, one day after, one week after, or weeks after pressure loading, and their middle ears were examined by a light microscope (LM), a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Hemorrhaging in the tympanic cavity immediately after pressure exposure was apparent even macroscopically. LM also revealed evidence of submucous hemorrhage. Submucous edema was seen in the "one week after" cases. SEM showed a minor loss of cilia in some ciliated cells just after the experiment. In nonciliated cells, the terminal web was somewhat indistinct in the "one week after" cases. TEM also indicated a minor loss of cilia in some ciliated cells in "one day after" cases as well as apparent vacuoles within the cells. These findings suggest that although trauma during compression is more marked than during decompression, recovery from this damage progressed with time.

Animals↗

PubMed1996

Serial angiographic follow-up after successful direct angioplasty for acute myocardial infarction.

This serial follow-up study was designed to identify the time course of reocclusion and/or restenosis after direct angioplasty for acute myocardial infarction. Direct angioplasty for acute myocardial infarction was attempted in 160 patients. Of the 141 patients who underwent successful reperfusion and were discharged, 137 (97%) were enrolled in this study. At the 3-week follow-up study (100% eligible), angiographic restenosis of the infarct-related artery was documented in 21 patients (16%), 9 (43%) of which were reocclusions. At 4 months in 100 patients (92% of those eligible), restenosis was newly documented in 28 infarct-related arteries (28%), 3 of which were reocclusions (11%). At 1 year in 64 patient (89% of those eligible), restenosis was newly documented in 5 infarct-related arteries (7.8%), with no reocclusions. The cumulative restenosis rate was 20% at 3 weeks, 43% at 4 months, and 47% at 1 year; when divided into occlusive and nonocclusive types, restenosis rates were 12% and 8.8% at 3 weeks and 14% and 29% at 4 months, respectively. Restenosis was most prevalent within the first 4 months and rarely occurred after that. When restenosis is manifested as reocclusion, it occurs earlier than in nonocclusive restenosis, often within 3 weeks.

Aged↗

PubMed1996

Intracerebroventricular injection of adrenomedullin inhibits vasopressin release in conscious rats.

The hypotensive peptide, adrenomedullin (AM), was first isolated from the tissue of human pheochromocytoma. Recently, AM-immunoreactivities have been found in the central nervous system, including the supraoptic and the paraventricular nuclei. In this study, the effect of centrally administered AM on arginine vasopressin (AVP) release was investigated in conscious rats. Intracerebroventricular injection of AM (1.0 microgram/rat) partially but significantly attenuated the plasma AVP increase induced by hyperosmolality (intraperitoneal (i.p.) injection of hypertonic saline (600 mosmol/kg)) at 30 min after the injection. It also significantly attenuated the plasma AVP increase induced by hypovolemia (i.p. injection of polyethylene glycol) at 30 min after the injection. These results suggest that central AM might play an inhibitory role in both osmo- and baro-regulation of plasma AVP.

Adrenomedullin↗

PubMed1996

Lack of increased coronary atherosclerotic risk due to elevated lipoprotein(a) in women > or = 55 years of age.

BACKGROUND: Numerous studies have indicated that there is an association between lipoprotein(a) [Lp(a)] and coronary artery disease (CAD) in middle-aged men; however, few studies have addressed this issue in women or the elderly. METHODS AND RESULTS: Serum Lp(a) concentrations were determined in 354 women and 706 men with or without angiographically defined CAD (one or more coronary arteries with narrowing of > or = 75%). The age-specific impact of elevated Lp(a) (> or = 30 mg/dL) on CAD was examined in each sex. In the younger age group (< 55 years old), elevated Lp(a) was independently associated with CAD in both sexes (adjusted odds ratio [OR]: women, 6.90, P < .01; men, 2.63, P < .05). The age-specific ORs declined with age, and elevated Lp(a) no longer conferred an increased CAD risk in either elderly men or women > or = 65 years old. In the age group of 55 to 64 years, elevated Lp(a) was positively associated with CAD for men (adjusted OR: 2.45, P < .05) but not for women (adjusted OR: 0.56, P = NS). CONCLUSIONS: For both sexes, elevated Lp(a) appears to be an independent risk factor for premature CAD and the importance of Lp(a) appears to decrease with age. However, for women, the risk estimate of Lp(a) began to decline at an age approximately 10 years younger than for men. These data suggest that not only age- but also sex-specific factors such as menstrual status may interact with the association between Lp(a) and CAD.

Aged↗