Search PubMed⌕ Search

Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 325 records · Page 18Linked to original sources
PubMed1999

Histological evaluation of coronary plaque in patients with variant angina: relationship between vasospasm and neointimal hyperplasia in primary coronary lesions.

OBJECTIVES: This study was designed to determine whether coronary vasospasm in patients with variant angina pectoris (VAP) may produce focal organic lesions at the site of vasospasm that would contribute to disease progression. BACKGROUND: Recent clinical angiographic and experimental studies have demonstrated the potential role of vasospasm in the worsening of organic coronary stenosis. METHODS: We studied histologically the coronary plaques obtained at atherectomy in 202 patients with moderate to severe coronary stenosis. This population included 22 patients with VAP, 100 patients with chronic stable angina and 80 patients with restenosis following angioplasty or atherectomy. Diagnosis of VAP was based on both the clinical feature of angina at rest associated with ST elevation and a positive response to acetylcholine provocation test. RESULTS: The most common histological appearance in 92% of patients with stable angina was hypocellular fibroatheromatous plaques, whereas neointimal hyperplasia was the characteristic feature of the plaque observed in 90% of patients with restenosis. The coronary specimens at the site of spasm in 15 of the 22 patients (68%) with VAP demonstrated intimal injuries such as neointimal hyperplasia (15), thrombus formation (2), and intimal hemorrhage (3). Neointimal hyperplasia was significantly more common in the patients with VAP as compared with those with stable angina (68% vs. 8%; p < 0.0001). A rapid progression of organic stenosis within three years was angiographically found in 5 of the 22 patients with variant angina. In all five cases, neointimal hyperplasia was the main contributor to the worsening of the organic lesion at the site of spasm. These histological findings in patients with VAP extremely resembled those in restenosis. Except for vasospasm, no factors significantly predicted the presence of neointimal formations in primary coronary lesions. CONCLUSIONS: Coronary vasospasm may provoke vascular injury that leads to the formation of neointima in VAP patients similar to that seen with restenosis. Coronary spasm may thus play a key role in the rapid coronary stenosis progression in certain patients with VAP.

Adult↗
PubMed1999

The effects of biphasic and conventional monophasic defibrillation on postresuscitation myocardial function.

OBJECTIVES: The purpose of this study was to compare the effects of biphasic defibrillation waveforms and conventional monophasic defibrillation waveforms on the success of initial defibrillation, postresuscitation myocardial function and duration of survival after prolonged ventricular fibrillation (VF). BACKGROUND: We have recently demonstrated that the severity of postresuscitation myocardial dysfunction was closely related to the magnitude of the electrical energy of the delivered defibrillation shock. In the present study, the effects of fixed 150-J low-energy biphasic waveform shocks were compared with conventional monophasic waveform shocks after prolonged VF. METHODS: Twenty anesthetized, mechanically ventilated domestic pigs were investigated. VF was induced with an AC current delivered to the right ventricular endocardium. After either 4 or 7 min of untreated ventricular fibrillation (VF), the animals were randomized for attempted defibrillation with up to three 150-J biphasic waveform shocks or conventional sequence of 200-, 300- or 360-J monophasic waveform shocks. If VF was not reversed, a 1-min interval of precordial compression preceded a second sequence of up to three shocks. The protocol was repeated until spontaneous circulation was restored or for a total of 15 min. RESULTS: Monophasic waveform defibrillation after 4 or 7 min of untreated VF resuscitated eight of 10 pigs. All 10 pigs treated with biphasic waveform defibrillation were successfully resuscitated. Transesophageal echo-Doppler, arterial pressure and heart rate measurements demonstrated significantly less impairment of cardiovascular function after biphasic defibrillation. CONCLUSIONS: Lower-energy biphasic waveform shocks were as effective as conventional higher energy monophasic waveform shocks for restoration of spontaneous circulation after 4 and 7 min of untreated VF. Significantly better postresuscitation myocardial function was observed after biphasic waveform defibrillation.

Analysis of Variance↗
PubMed1999

Endovascular stent graft repair of aortopulmonary fistula.

Two patients who had aortopulmonary fistula of postoperative origin with hemoptysis underwent successful repair by means of an endovascular stent graft procedure. One patient had undergone repeated thoracotomies two times, and the other one time to repair anastomotic aneurysms of the descending aorta after surgery for Takayasu's arteritis. A self-expanding stainless steel stent covered with a Dacron graft was inserted into the lesion through the external iliac or femoral artery. The patients recovered well, with no signs of infection or recurrent hemoptysis 8 months after the procedure. Endovascular stent grafting may be a therapeutic option for treating patients with aortopulmonary fistula.

Anastomosis, Surgical↗
PubMed1999

Efficacy of NND-502, a novel imidazole antimycotic agent, in experimental models of Candida albicans and Aspergillus fumigatus infections.

In vitro and in vivo anti-Candida albicans and anti-Aspergillus fumigatus activities of NND-502, a new imidazole-antimycotic, were compared with those of fluconazole (FCZ), itraconazole (ITZ) and/or amphotericin B (AmB). NND-502 exhibited strong in vitro antifungal activity against both fungal species; its MIC against C. albicans was 1-4 times lower than that of FCZ, and its MIC against A. fumigatus was at least 60-2000 times lower than that of ITZ and AmB. In vivo antifungal treatments with each drug were initiated 1 h after inoculation in the experimental models, so that antifungal potential reflected prophylactic activity rather than therapeutic activity. The oral regimen of NND-502 in a murine model of systemic C. albicans infection was much less effective than that of FCZ. In vivo anti-A. fumigatus activity of oral NND-502 in a murine model of systemic infection was apparently superior to that of FCZ and ITZ in terms of prolonging survival. In addition to the murine model of systemic aspergillosis, intravenous NND-502 was shown to be highly effective in a rat model of pulmonary aspergillosis compared with intravenous AmB; 90% of animals survived at a dose of 2.5 mg/kg per day of NND-502 while only 30% of animals escaped death when 5 mg/kg per day of AmB was used. This potent efficacy of NND-502 was also confirmed in a sublethal challenge study in which the administration of the agent at a dose as low as 1.25 mg/kg per day resulted in the significant reduction of organisms in the lung; no comparable effect of AmB was found.

Amphotericin B↗
PubMed1999

In vitro digestibility and fermentability of levan and its hypocholesterolemic effects in rats.

This study describes the in vitro digestibility and fermentability of high molecular weight (ca. 2,000,000) levan and its effect on the metabolism of lipids in growing rats fed cholesterol-free diets. Levan was synthesized from sucrose using bacterial levansucrase immobilized on a honeycomb-shaped ceramic support. Although body weight gain, weight of visceral organs, morphologic changes in the digestive tract, and the serum triacylglycerol and glucose concentrations were not affected by feeding levan diets for 4 weeks, a significant hypocholesterolemic effect was observed. Serum cholesterol level was decreased to 83% or 59% by feeding a 1% or 5% levan diet, respectively. The hypocholesterolemic effect was accompanied by a significant increase in fecal excretion of sterols and lipids. High molecular weight levan, though not hydrolyzed by the salivary amylases, was hydrolyzed by artificial gastric juice and was changed to a low molecular weight (ca. 4,000) levan with a small amount of fructose, but did not produce any fructooligosaccharides. Low molecular weight (ca. 6,000) levan was not hydrolyzed by either pancreatic juice or small intestinal enzymes. This suggests that, in vivo, low molecular weight levan derived from the high molecular weight material is not further digested and reaches the colon intact. The fermentation of low molecular weight levan (ca. 6,000) by several strains of bifidobacteria was not observed. These results showed that the hypocholesterolemic effect of levan may result from the prevention of intestinal sterol absorption, and not from the action of the fermentation products of levan.

Journal Article↗
PubMed1999

Chemical studies on antioxidant mechanism of curcuminoid: analysis of radical reaction products from curcumin.

In the course of studies on the antioxidant mechanism of curcumin, its radical reaction was investigated. Curcumin was reacted with radical species, which were generated from the pyrolysis of 2, 2'-azobis(isobutyronitrile) under an oxygen atmosphere, and the reaction products from curcumin were followed by HPLC. The reaction at 70 degrees C gave several products, three of which were structurally identified to be vanillin, ferulic acid, and a dimer of curcumin after their isolation. The dimer was a newly identified compound bearing a dihydrofuran moiety, and its chemical structure was elucidated using spectroscopic analyses, especially 2D NMR techniques. A mechanism for the dimer production is proposed and its relation to curcumin's antioxidant activity discussed. The time course and gel permeation chromatography studies of the reaction were also investigated, and the results indicate that the dimer is a radical-terminated product in the initial stage.

Antioxidants↗
PubMed1999

Mouse colitis induced by Escherichia coli producing Yersinia enterocolitica 60-kilodalton heat-shock protein: light and electron microscope study.

In patients with inflammatory bowel disease (IBD), including ulcerative colitis (UC), heat-shock protein (Hsp) 60 has been detected in serum and the intestinal tract. Our mouse colitis model was established using Escherichia coli transformed with Yersinia enterocolitica Hsp60 gene as an immunizing antigen, and examined light and electron microscopically as compared with lesions of UC. The large intestine of mice injected with Hsp60 antigen showed swollen goblet cells, glandular dilation, erosion, ulceration, and infiltration of inflammatory cells. The change like crypt abscesses was also found, and various phases of inflammation were observed simultaneously in individual mice. In addition, the reticulum fibers were absent ultrastructurally in the subepithelial reticular layer. Hyperplasia of the thymus was found in antigen-treated mice. These lesions were similar to those of UC. These results suggest that UC-like enteritis in mice was induced by using Hsp60, considered as one of the pathogens for UC.

Animals↗
PubMed1999

Allogeneic hematopoietic stem cell transplantation for patients with hemophagocytic syndrome (HPS) in Japan.

Seventeen cases (age at onset, 1 month to 18 years; M/F, 9/8) of hemophagocytic syndrome which received allogeneic hematopoietic stem cell transplantation (SCT) in Japan during the period 1988-1998 are reported. The patients consisted of six familial inheritance-proven erythrophagocytic lymphohistiocytosis (FEL), five familial inheritance-unknown and infective agents-unknown HLH (of which two were highly likely to have been FEL with characteristic CNS signs), and six aggressive Epstein-Barr virus (EBV)-related HLH (of which two were natural killer cell-type large granular leukemia/lymphoma-associated hemophagocytic syndrome, EBV-NK-LGLL-HPS). All cases were treated intensively with immuno-chemotherapy, or with chemotherapy before SCT. As sources of SCT, 12 cases received bone marrow cells (sibling six, father one, URD five), two cord blood, two purified CD34-positive cells, and one PBSC. SCTs were successful in all 17 cases, apart from one receiving CD34-positive SCT. Following SCT, four patients relapsed and five died with a median follow-up of 23 months. Among the relapsed cases, the two EBV-NK-LGLL-HPS previously published as successfully transplanted were included. Among the fatal cases, three patients died from relapsed active disease and the remaining two from fatal post-SCT EBV-positive T cell lymphoma and extensive chronic GVHD, respectively. As of the end of September 1998, 10 patients are alive without disease for 3.5 months to 147 months, while two post-SCT patients are still having therapy for residual/recurrent disease. The Kaplan-Meier analysis showed a 2-year event-free survival after SCT as 54.0+/-13.0%.

Adolescent↗
PubMed1999

Establishment of a near-triploid human B-cell lymphoma cell line with t(14;18) and a p53 gene point mutation.

We report a rare large B-cell non-Hodgkin's lymphoma having a characteristic near-triploid cell population with add(17)(p22) and t(14;18)(q32;q21) translocation. We also established and characterized a new cell line (TK cell) derived from the present lymphoma. A codon 180 mutation (GAG --> GAT) in the p53 gene was detected. t(14;18)(q32;q21) was revealed juxtaposition of the bcl-2 and JH genes. Immunoprecipitation analyses of p53 and bcl-2 revealed that abnormality of the p53 protein and aberrant bcl-2 expression, which may protect cells from apoptosis, may be critical to the development of leukaemogenesis exhibiting near-triploid chromosomes.

Aged↗
PubMed1999

Inhibition of sterol 14 alpha-demethylation of Candida albicans with NND-502, a novel optically active imidazole antimycotic agent.

To investigate the mode of action of the newly synthesized optically active imidazole compound, NND-502, (-)-(E)-[4-(2, 4-dichlorophenyl)-1,3-dithiolan-2-ylidene]-1-imidazolylacetonit rile, its effect on ergosterol biosynthesis in cell-free extracts of Candida albicans was examined and compared with that of the (S)-enantiomer of NND-502 in addition to lanoconazole and bifonazole, both of which are clinically used for the treatment of dermatomycoses. NND-502 was found to interfere with ergosterol biosynthesis by inhibition of sterol 14alpha-demethylase, while no interference due to the (S)-enantiomer of NND-502 was found, indicating that the stereochemical orientation of the 2, 4-dichlorophenyl group plays an important role in the interaction with the enzyme. In terms of drug concentration exerting 50% inhibition of ergosterol biosynthesis, NND-502 was 2.5 and 28 times more effective than that of lanoconazole and bifonazole, respectively.

Antifungal Agents↗
PubMed1999

Two-dimensional electrophoresis of Malassezia allergens for atopic dermatitis and isolation of Mal f 4 homologs with mitochondrial malate dehydrogenase.

The yeast Malassezia furfur is a natural inhabitant of the human skin microflora that induces an allergic reaction in atopic dermatitis. To identify allergens of M. furfur, we separated a crude preparation of M. furfur antigens as discrete spots by 2-D PAGE and detected IgE-binding proteins using sera of atopic dermatitis patients. We identified the known allergens, Mal f 2 and Mal f 3, and determined N-terminal amino acid sequences of six new IgE-binding proteins including Mal f 4. The cDNA and genomic DNA encoding Mal f 4 were cloned and sequenced. The gene was mitochondrial malate dehydrogenase and encoded Mal f 4 composed of 315 amino acids and a signal sequence of 27 amino acids. We purified Mal f 4, which had a molecular mass of 35 kDa from a membrane fraction of a lysate of cultured cells. Thirty of 36 M. furfur-allergic atopic dermatitis patients (83.3%) had elevated serum levels of IgE to purified Mal f 4, indicating that Mal f 4 is a major allergen. There was a significant correlation of the Phadebas RAST unit values of Mal f 4 and the crude antigen, but not between Mal f 4 and the known allergen Mal f 2.

Allergens↗
PubMed1999

Brachyury (T) expression in embryonal carcinoma P19 cells resembles its expression in primitive streak and tail-bud but not that in notochord.

Brachyury (T) is involved in mesoderm induction during early mouse development. T expression in embryonal carcinoma P19 cells, which differentiate into mesoderm derivatives in vitro, was studied. Endogenous T expression in P19 cells was transiently induced when the cells were allowed to form aggregates. This expression was enhanced by dimethyl sulfoxide. In situ hybridization showed that T expressing cells formed clusters on the aggregates. Transfection of plasmids encoding reporter genes under the control of the upstream region of T showed that the sequence up to -351 bp can resemble the differentiation-dependent expression of T in P19 cells. To define the promoter region regulating T expression, transgenic mice carrying LacZ under the control of the upstream region were prepared. The region up to -351 bp is sufficient to direct the expression in the primitive streak and tail-bud. The upstream region up to -2400 bp does not support expression in the notochord. The sequence between -987 and -585 bp enhances expression in the primitive streak and tail-bud. In the tail-bud where new cells for elongation of the anteroposterior axis were continuously supplied, the sequence up to -987 bp drove lacZ expression in gut endoderm and prospective neuroectoderm as well as in mesoderm derivatives.

Animals↗
PubMed1999

Proliferation of hepatic metastases of colorectal carcinoma: relationship to primary tumours and prognosis after hepatic resection.

In this study, we determined the proliferation indices of liver metastatic tumours originating from colorectal carcinomas using Ki67 and argyrophil nucleolar organizer region associated proteins (AgNOR) stain. We examined the primary and metastatic tumours in 27 patients with liver metastasis and eight cases with non-metastatic colorectal carcinoma as a control.The number of AgNOR dots in metastatic tumours was significantly higher than in the respective primary tumours of the metastasis group or in non-metastatic colorectal carcinomas. The Ki67 labelling index was similar in all groups. The Ki67 labelling index and AgNOR counts did not correlate with each other. There was no significant relationship between proliferation indices and the duration of the disease-free period following hepatic resection for metastases or with prognosis after hepatectomy. We conclude that Ki67 and AgNOR are not useful indicators of prognosis in patients who undergo operation for liver metastasis of colorectal carcinomas.

Adult↗
PubMed1999

Expression of adhesion molecules in hepatic metastases of colorectal carcinoma: relationship to primary tumours and prognosis after hepatic resection.

BACKGROUND: Adhesion molecules are closely involved in the development and growth of metastatic tumours. METHODS: We examined the expression of two adhesion molecules in liver metastatic tumours originating from colorectal carcinomas and correlated the expression of E-cadherin (EC) and CD44 variant exon 6 (v6) in these tumours with prognosis after hepatic resection. We examined 39 primary colorectal and 44 liver metastatic tumours obtained from 39 patients and 30 non-metastatic colorectal carcinomas as controls. The expression of EC in primary colorectal carcinomas of the metastasis group was significantly lower than in the non-metastasis group (P < 0.05). The expression of EC was low in metastatic liver tumours. RESULTS: The expression of CD44v6 in primary colorectal carcinomas of the metastasis group was significantly higher than in the non-metastasis group (P < 0.01). Expression of CD44v6 was high in metastatic liver tumours. However, there was no correlation between the expression of EC and CD44v6 or between each of these molecules and clinicopathological features of primary and metastatic tumours. Negative expression of EC and CD44v6 was a poor prognostic factor for survival after hepatic resection. CONCLUSIONS: Our results indicate that the lack of expression of EC and CD44v6 in liver metastases of colorectal cancer is associated with poor survival after surgery.

Aged↗
PubMed1999

Heterotopic sebaceous glands in the esophagus: histopathological and immunohistochemical study of a resected esophagus.

A resected esophagus with numerous heterotopic sebaceous glands was examined in an attempt to determine whether esophageal heterotopic sebaceous glands are the result of a metaplastic process or a congenital anomaly. The present case concerns a 79-year-old Japanese man with numerous esophageal heterotopic sebaceous glands accompanied by superficial esophageal cancer. The resected esophagus possessed numerous heterotopic sebaceous glands, which could be seen clearly as slightly elevated, yellowish lesions. Histological examination of these glands, all of which were located in the lamina propria, revealed lobules of cells that showed characteristic sebaceous differentiation. Bulbous nests of proliferating basal cells showing sebaceous differentiation were occasionally observed in the esophageal epithelium. Of the antibodies against six different keratins used, only anti-keratin 14 labeled both the heterotopic sebaceous glands and the bulbous nests. Acquired metaplastic change of the esophageal epithelium is probably the pathogenetic mechanism involved in these unusual lesions.

Aged↗
PubMed1999

Paraneoplastic vasculitis associated with esophageal carcinoma.

We report a case of esophageal carcinoma associated with paraneoplastic vasculitis. A 69-year-old man suffered from low-grade fever and numbness of the lower limbs for 3 months before esophageal and gastric carcinomas were detected. Concurrent infection or collagen disease was ruled out following clinical and laboratory examinations. In April 1996, the gastric carcinoma was completely removed by endoscopic mucosal resection, but the symptoms remained. Three weeks later esophagectomy was performed for esophageal carcinoma after which time the fever and numbness disappeared. The esophageal carcinoma was a well-differentiated squamous cell carcinoma invading into the submucosal layer. Twenty-two lymph node metastases were found in 68 resected lymph nodes. Latent thyroid cancer was found. Histologically, vasculitis was detected in the esophagus, stomach and serratus anterior muscle. The distribution and degree of vasculitis were most pronounced in the esophagus. The concurrent onset and spontaneous resolution of fever and numbness after the removal of the esophageal carcinoma suggested a paraneoplastic origin. The majority of patients with malignant neoplasm-associated vasculitis had hematologic neoplasms. Cases of esophageal carcinoma associated with paraneoplastic vasculitis are extremely rare.

Aged↗
PubMed1999

Effect of an aluminum hydroxide-magnesium hydroxide combination drug on adhesion, IL-8 inducibility, and expression of HSP60 by Helicobacter pylori.

BACKGROUND: Co-magaldrox (Maalox) is used world-wide as an antacid and as a cytoprotective agent for gastritis and peptic ulcer diseases. We examined the effects of co-magaldrox on Helicobacter pylori. METHODS: Adhesion of H. pylori to human gastric epithelial cells (MKN45) was evaluated by flow cytometry. Morphologic changes in H. pylori caused by co-magaldrox were determined by scanning electron microscopy. Induction of interleukin-8 (IL-8) from MKN45 cells was examined with enzyme-linked immunosorbent assay, and the intracellular and extracellular expression of heat-shock protein 60 (HSP60) was analyzed with sodium dodecyl sulphate-polyacrylamide gel electrophoresis and flow cytometry. RESULTS: Adhesion of H. pylori to MKN 45 cells was significantly inhibited by 1.25%-5% comagaldrox. H. pylori aggregated with co-magaldrox according to an electron microscopic examination. IL-8 secretion from MKN45 cells after H. pylori infection was also inhibited by co-magaldrox. Extracellular expression of HSP60 on the surface of H. pylori was decreased after treatment with comagaldrox, whereas the intracellular synthesis of HSP60 was not. HSP60-induced IL-8 secretion was significantly inhibited by co-magaldrox in a dose-dependent manner. CONCLUSIONS: These results show that co-magaldrox suppressed the expression of the following virulence factors: adhesion, IL-8 inducibility, and expression of extracellular HSP60. Therefore, co-magaldrox is a potent anti-H. pylori and cytoprotective drug.

Aluminum Hydroxide↗