Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 469 records · Page 26Linked to original sources

PubMed1998

Squamous odontogenic tumor of the maxilla: report of a case.

A case of squamous odontogenic tumor (SOT) of the maxilla related to an embedded tooth in a 42-year-old Japanese woman is described. The patient felt a slight pain of her left maxilla 2 months before visiting our dental hospital. Histologically, the tumor consisted of a proliferation of round and elongated epithelial islands of well-differentiated squamous epithelium separated by a fibrous stroma. The epithelial nests varied in size, and were composed of cuboidal or squamous cells of basal layer and matured intermediate cells with prominent intercellular bridges. Although no calcified materials were found, microcystic degeneration was occasionally observed in the epithelial islands. These findings indicated that this tumor is a SOT of the maxilla.

Adult↗

PubMed1998

Protective effect of oral administration of a traditional medicine, Juzen-Taiho-To, and its components on lethal Candida albicans infection in immunosuppressed mice.

Protective effects of a kampo medicine, Juzen-taiho-to (TJ-48) and its herbal components against experimental candidiasis in cyclophosphamide-induced immunosuppressive mice were investigated. ICR mice were immunosuppressed by intraperitoneal treatment with cyclophosphamide (day-4) and were orally given TJ-48 or one of its 10 herbal components for 4 consecutive days (day-4--1). They were then challenged intravenously with a lethal dose of Candida albicans (day 0). An oral dose of 1 g/kg/day of TJ-48 prolonged their life span. A similar protective effect was obtained by treatment with its component drugs Ginseng radix, Glycyrrhizae radix, Atractylodis lancea rhizoma or Cnidii rhizoma. These herbal components were suggested to have a main role in the protective effect of Juzen-taiho-to against Candida infection.

Adjuvants, Immunologic↗

PubMed1998

Role of umbilical vein endothelial cells in hematopoiesis.

Effective hematopoiesis is usually induced by interactions between hematopoietic progenitor cells (HPC) and stromal cells. In cord blood (CB), umbilical vein endothelial cells (HUVEC) can support HPC as a stromal microenvironment. EC activated mainly by IL-1 and TNFalpha produce a variety of cytokines and growth factors such as IL-1, IL-4, IL-6, GM-CSF and G-CSF. Since HPC express c-kit on their surface, the SCF produced by HUVEC plays an important role in the hematopoiesis of CB. We examined the expression of cytokines and growth factors on HUVEC by PCR. Resting HUVEC expressed high level of SCF, and low levels of IL-6, IL-7, and IL-8. Thus, a variety of cytokines and growth factors are produced by EC, and this cytokine network is thought to play an important role in regulating hematopoiesis. Activated EC can also express various adhesion molecules including E-selectin, VCAM-1 and ICAM-1, and facilitate the adhesion of hematopoietic cells to the endothelium. Furthermore, the interaction of CB cells with HUVEC has recently been shown in vitro. We previously showed that the culture media of HUVEC induced high numbers of colony formation. Suitable cytokine productions are thus provided to HPC by the interaction of HUVEC and cord MNC. On the basis of these findings, several mechanisms to support hematopoiesis in CB can be considered. Specific growth factors produced by EC bind to HPC to induce proliferation. While cell-cell interactions involve adhesion of HPC to HUVEC via adhesion molecules, and the adhesion of HPC to EC will facilitate interaction with cytokines and growth factors. Thus HPC in CB proliferate and are maintained by growth factors, and adhesion molecules produced by HUVEC, and HPC themselves.

Cell Adhesion Molecules↗

PubMed1998

Baroreceptor activation causes release of acetylcholine in the rostral ventrolateral medulla of the rat.

We examined whether baroreceptor activation causes a release of acetylcholine (ACh) in the rostral ventrolateral medulla (RVLM) of the rat, in order to investigate a possible connection between RVLM cholinergic systems and cardiovascular baroreflexes. Male Wistar rats were anesthetized, paralyzed and artificially ventilated. Either electrical stimulation of aortic nerve or baroreceptor activation by intravenous phenylephrine produced an increase of the release of ACh in the RVLM, whereas baroreceptor denervation and tetrodotoxin (TTX) microinfusion in the RVLM inhibited the increase in ACh release induced by phenylephrine. TTX injected in the caudal ventrolateral medulla (CVLM) inhibited the phenylephrine-induced increase of ACh release. The excitatory amino acid L-glutamate microinfused in the CVLM produced an release in ACh release in the RVLM. These results suggest that there is a connection between RVLM cholinergic systems and cardiovascular baroreflexes. It is probable that neurons in the CVLM are involved in mediating the release of ACh in the RVLM.

Acetylcholine↗

PubMed1998

[Anti-Candida activities of azole antifungals in the presence of lysozyme in vitro].

The combined effects of lysozyme and various antifungal agents were investigated by microbroth dilution method against Candida albicans in vitro. Synergistic anti-Candida activity was observed between egg white lysozyme and itraconazole, clotrimazole, miconazole and lanoconazole. Similar, although not as clear, combination anti-Candida activities were seen in the cases of ketoconazole, bifonazole, amphotericin B and nystatin. Anti-Candida activity of fluconazole was not affected by the addition of lysozyme, however. Physiological roles of this combination effect in anti-Candida therapy by azole antifungals were discussed.

Anti-Infective Agents↗

PubMed1998

[Cooperative inhibitory effects of cervical mucus and neutrophils on growth of Candida albicans].

Preparations of human cervical mucus were obtained from fifteen female volunteers with or without vaginal candidiasis. Their content of lactoferrin and inhibitory effects on the growth of Candida albicans were estimated. The concentration of lactoferrin in cervical mucus was measured by enzyme linked immunosorbent assay (ELISA). Lactoferrin concentration of the eleven preparations among them was more than 0.2 mg/ml. The effects of these cervical mucus preparations on Candida growth were examined in vitro. Candida growth was not inhibited by the addition of 1/200 diluted cervical mucus alone, however, anti-Candida activity of murine neutrophils was augmented by such an addition. These results suggest that the combination of neutrophils and cervical mucus may have an important role in defense against Candida infection in the vaginal mucosa.

Adult↗

PubMed1998

[Augmentation of anti-Candida activity of neutrophils by macrophages treated with itraconazole].

Effects of itraconazole (ITCZ) on anti-Candida activity of a macrophage (MP)-neutrophil axis were examined in vitro. Murine peritoneal MP, stimulated by an enterococcal preparation FK-23, released tumor necrosis factor a (TNF) into the culture medium in 20 hr-culture period. This level of TNF production by the stimulated MP, which were measured by a bioassay or immunological assay, was heightened by co-stimulation with 0.5 mg/ml of ITCZ. Supernatants obtained from the culture medium of FK-23 and ITCZ-treated MP not only contained about 10 ng/ml of TNF but also had the capacity to enhance anti-Candida activity of murine neutrophils. This enhancement was blocked by pretreatment of the MP-supernatant with anti-TNF antibody. Observation by scanning electron microscope suggested that cell walls of the candida mycelia, the growth of which was inhibited by the neutrophils in the presence of either the MP-supernatant or TNF, sustained similar structural damage. These results suggest that ITCZ augments anti-Candida activity of neutrophils through enhanced production of TNF by MP in vitro.

Animals↗

PubMed1998

High level of lipoprotein(a) is a strong predictor for progression of coronary artery disease.

Elevated levels of serum lipoprotein(a) [Lp(a)] are reported to be associated with risk of atherosclerosis and thrombosis. Little is known about the influence of Lp(a) on the progression of coronary artery disease. We evaluated the association of serum Lp(a) and the long-term changes of angiographic severity in patients who underwent repeated coronary angiography at intervals of more than 2 years. We evaluated 70 patients, and divided them into 3 groups by angiographic findings. Median Lp(a) concentration was significantly higher in the progression group (N=36) than in the no-change group (N=23) or the regression group (N=11) (32.4 vs 22, 19.3 mg/dl, p<0.05). Furthermore, the progression group had more patients whose Lp(a) levels were greater than 30 mg/dl (p=0.006), while in the regression group all patients were under 30 mg/dl. Stepwise logistic regression analysis for progression of lesions showed that Lp(a) > or =30 mg/dl remained significant, giving an estimated odds ratio (OR) of 2.46 (p= 0.005). In the subgroup analysis, OR in patients with mild lesions was reduced to 2.05 (p<0.05) while in patients with severe lesions OR was increased to 3.39 (p=0.003). The serum Lp(a) level has a close correlation with angiographic progression, and may be an important predictor for progression.

Aged↗

PubMed1998

[Unclassified cardiomyopathies: subspecies and their transformation].

Some cases with hypertrophic cardiomyopathy (HCM) progress to dilated cardiomyopathy (DCM), therefore, we hypothesized that a transforming-type phase between HCM and DCM could exist. This study was made based on a retrospective analysis of 471 of 1,388 patients with cardiomyopathy who underwent diagnostic myocardial biopsy in several hospitals between 1977 to 1995, and who were not diagnosed with restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, specific heart muscle diseases, or electrical disturbance type of heart muscle diseases. Based on echocardiographic measurements, the 471 patients were classified into eight subgroups according to the presence or absence of three parameters. A: left ventricular hypertrophy (septal or posterior wall thickness > 12 mm), B: left ventricular dilation (left ventricular end-diastolic dimension > 55 mm), C: systolic dysfunction (left ventricular ejection fraction < 50%), is signified by plus or minus ([ABC]). HCM, DCM and normal heart are defined as [+(-)-], [-(+2)] and [-(-)-], respectively. Unclassified cardiomyopathy (UCM) was indicated as cardiomyopathy not diagnosed as HCM or DCM. Therefore, unclassified cardiomyopathies are signified as either [+2-], [+(-)+], [+3], [-(+)-] or [-(-)+]. Patients in each subgroup of UCM were followed up for 6.4 +/- 6.0 years and their clinical courses compared with the histological findings. Of the 471 patients, 111 (24%) were classified as UCM, 240 as HCM, and 120 as DCM. Severe myocardial disarray was noted more frequently in UCM [17 of 111 cases (15%)] than in DCM [7 of 120 cases (6%)] (p < 0.05), and not significantly higher than in HCM [34 of 240 cases (14%)]. Patients with UCM whose conditions deteriorated had positive pathological findings (15 of 26 cases) more often than those without deterioration (8 of 29 cases; p < 0.05). UCM could be a transforming type of cardiomyopathy for some patients with HCM who progress to DCM. In addition, there may be a positive correlation between the histopathologic findings and the clinical course.

Cardiomyopathies↗

PubMed1998

Transcriptional regulation of fatty acid cyclooxygenases-1 and -2.

Transcriptional regulation of fatty acid cyclooxygenase isozymes (COX-1 and COX-2) were studied using two cell lines. A rapid and transient induction of COX-2 was observed by the addition of tumor necrosis factor alpha (TNF alpha) to murine osteoblastic cells MC3T3-E1. Possible involvement of NF kappa B and NF-IL6 as transcription factors was shown by deletion experiments using a luciferase reporter gene. COX-1 induction by a phorbol ester was demonstrated along with differentiation of human megakaryoblastic cells CMK to megakaryocytes.

Animals↗

PubMed1998

[Neural protective agents, propentofylline (PPF) could induce apoptotic cell death in the human glioma cells: analysis of Bcl-2 and Bax alpha/Bax beta expressions].

In the previous study, we have shown that propentofylline (PPF) could induce the cellular differentiation and apoptosis-related growth regression in the human glioma cell lines. Its biological functions were partly due to the increasing endogeneous NGF and its high affinity receptor, trk A productions. Although little has been known about the precise machinary regulating the propentofylline induced apoptosis. Recently, we have found that propentofylline could modulate some apoptosis related genes products in the glioma cell lines, i.e. NGF, trk A mRNA levels and Fas protein expressions were increased, whereas bcl-2 mRNA level was decreased. In the present study, we examined the apoptotic signal cascade, especially focusing on the expressing pattern of Bcl-2/Bax gene products. In the normal human astrocyte cells, Bax-beta was markedly expressed, whereas Bcl-2 and Bax-alpha proteins and mRNA were weakly or even nondetectable. Accordingly, Bax beta might be a dominant variant in the normal glial cells, which could have the appropriate balance of proapoptotic (Bax beta) and anti-apoptotic proteins (Bcl-2). In the glioma cells, we showed the over-expressions of Bcl-2 and Bax alpha compared with the normal counterparts. According to Bax dominant theory, Bax, not Bcl-2 may have a major role in regulating apoptosis by means of homodimerization. In might be implied that in the glioma cells, excessive expressions of Bcl-2 and Bax alpha would favor the formation of the Bax alpha/Bax beta heterodimer or the Bax beta/Bcl-2 heterodimer rather than the Bax beta/Bax beta homodimer, which might be presumed to be functional proteins. And finally the increasing relative ratio of Bax alpha/ Bax beta or Bax beta/Bcl-2 to Bax beta/Bax beta could allow the tumor cells to survive. Thus over-expression of the bcl-2 and bax alpha gene renders the glioma cells resistant to apoptosis. In the present study, PPF could promote Bax beta over-expression and Bcl-2 retardative expression in the glioma cells, whereas had no effect on Bax alpha expression. Therefore, PPF might promote apoptotic cell death through the mechanism that restore the glioma cells to the appropriate balance of proapoptotic and anti-apoptotic proteins like as normal astrocytes. Our results indicated that propentofylline might have a potential role as apoptotic modulators in the human glioma cell lines, not only its protective activities against neuronal ischemic damages.

Apoptosis↗

PubMed1998

[Induction of apoptosis through NGF/p75NTR in human glioma cells treated with propentofylline].

Propentofylline (PPF) is a xanthine derivative and it has been reported that PPF stimulated the synthesis/secretion of nerve growth factor (NGF) by cultured astroglial cells. We have reported that PPF induced apoptosis in human glioma cells and as its mechanism, up-regulation of NGF, Fas, Bax beta and down-regulation of Bcl-2 were assumed. Recent studies demonstrated the presence of apoptosis induced via NGF/p75NTR in developmental neuron, oligodendroglia. In the present study, to examine whether signal cascade via NGF/p75NTR participates the apoptosis in human glioma cells treated with PPF, we investigated the immunohistochemical study using anti-mouse monoclonal antibody, immunoprecipitation and northern blot analysis for p75NTR, NF-kappa B in human glioma cells (U251MG, T98G, U87) treated with PPF. We observed the up-regulation of p75NTR, translocation of NF-kappa B to the nucleus after treatment with PPF in these cell lines. According to above results, it is assumed that apoptosis in human glioma cells treated with PPF was induced via NGF/p75NTR.

Apoptosis↗

PubMed1998

Mitral valve aneurysm as a sequela of infective endocarditis: review of pathologic findings in Japanese cases.

Mitral valve aneurysm is defined as a localized protrusion of the valve with a different radius from that of the remaining portion of the valve. The medical records and pathological findings of seven patients with mitral valve aneurysm [aged 48-69 years (mean 64), 4 males] and the pathological findings of other 29 Japanese cases were reviewed. All seven patients were diagnosed pathologically as infective endocarditis, but two patients had no documentation of clinical symptoms suggestive of infective endocarditis (latent infective endocarditis). The underlying lesion of the heart was aortic valve disease and/or fibrosal degeneration of the mitral valve. Only 29 of 36 Japanese case reports stated a precise description of the valve pathology. Of these 29 cases, 23 were associated with infective endocarditis, two with rheumatic valvular disease with fusion and/or shrinkage of the chordae tendineae, three with mitral valve prolapse or myxomatous degeneration of the mitral valve, and one with aortitis syndrome. Neovascularization was described in eight cases. Neovascularization with thick wall should be considered as post-inflammatory vascularization. This review indicates that patients with latent infective endocarditis and mitral valve aneurysm should be considered as potential candidates for valve surgery.

Aged↗

PubMed1998

Assessment of cardiac autonomic nervous activities during heliox exposure at 24 atm abs.

BACKGROUND: This experiment was designed to examine the involvement of the autonomic nervous system in the production of hyperbaric bradycardia. METHODS: Four male divers were exposed to a He-O2 (heliox) environment at 24 atmosphere absolute (atm abs) for 7 d. The heart rate (HR) and respiratory rate were recorded at rest in the morning (0700 h) and at night (2230 h) on 1 d during a 5-d predive control, 2 d during a 7-d saturation dive at 24 atm abs, 2 d during decompression, and on 1 d during a 4-d postdive period. Cardiac sympathetic and parasympathetic activities were estimated by using a spectral analysis of the variability of R-R intervals. RESULTS: The morning HR did not fluctuate throughout the experimental days. The night time HR decreased (p < 0.05) by 11.8% on the first day at 24 atm abs compared with that of the predive control. The bradycardia diminished gradually and returned to the predive level with continued exposure at 24 atm abs. The high-frequency power of the cardiac variability, an index of cardiac parasympathetic activity, increased (p < 0.05) only in the first night at 24 atm abs, whereas the low-frequency power and a ratio of low- to high-frequency power, an index of cardiac sympathetic activity, were unchanged. CONCLUSIONS: The present results suggest that an increased parasympathetic activity rather than a decrease in the sympathetic activity is responsible for the bradycardia on exposure to heliox dry saturation dive at 24 atm abs. The mechanism of the gradual disappearance of the bradycardia is unknown, but perhaps it may be related to the development of cardiovascular deconditioning.

Adult↗

PubMed1998

[An adult case of Reye syndrome induced by diclofenac sodium, and recovered by plasma exchange].

Reye syndrome (RS) is an acute encephalopathy in childhood, and is very rare in adulthood. Here we report a 21-year-old woman with RS. Because of her dysmenorrhea, she took 3 tablets of diclofenac sodium (25 mg) per day in 3 divided doses for two days. Two days after the last intake of the medicine, she developed high fever, nausea, vomiting, and disturbance of consciousness with delirium, i.e., acute encephalopathy. She did not have seizure, hemiplegia, or other focal neurological manifestations. The serum GOT level was normal at onset, but in 12 hours dramatically increased up to 8,632 IU/L. The serum bilirubin level was normal. The cerebrospinal fluid revealed normal cell count, and protein. Although the liver biopsy was not performed because of thrombocytopenia, we diagnosed her as an adult case of RS according to the clinical criteria of the Center for Disease Control. In addition to treatment for the brain edema, plasma exchange was performed once treat the encephalopathy at the onset. The next day, her consciousness level and serum GOT level markedly improved. She completely recovered from acute encephalopathy in a week after her admission. In conclusion, diclofenac sodium, as well as aspirin, should be considered as a possible causal agent for RS, and early plasma exchange may be beneficial.

Adult↗

PubMed1998

Relationship between expression of HSP60, urease activity, production of vacuolating toxin, and adherence activity of Helicobacter pylori.

The relationship between the expression of heat shock protein 60 (HSP60) of Helicobacterpylori on the bacterial surface and its pathogenic factors of urease activity, production of vacuolating toxin, and adherence to human gastric carcinoma cells was examined. There was no correlation between urease activity, production of vacuolating toxin, and the expression of HSP60. However, there was a significant correlation between the adherence activity to human gastric carcinoma MKN45 cells and the expression of HSP60 (correlation coefficient; r = 0.68). In an inhibition assay with anti-HSP60 antibody, we examined the adhesion of H. pylori to MKN45 cells. The adherence of 3 of 13 H. pylori strains was inhibited by anti-HSP60 antibody. The results suggest that H. pylori HSP60 may be associated with the adhesion of H. pylori to human gastric cells.

Bacterial Adhesion↗

PubMed1998

Characteristics of Helicobacter pylori strains isolated from patients with different gastric diseases.

The pathogenesis of chronic gastritis, gastric ulcer, duodenal ulcer, gastric cancer, and remnant gastritis is considered to be related to infection by Helicobacter pylori. The purpose of this study was to investigate the characteristics of H. pylori strains isolated from patients with various gastric diseases. Fifty strains of H. pylori were clinically isolated at Keio University Hospital and were assessed for (i) vacuolating cytotoxin (VT) production, by cytotoxic assay using rabbit kidney (RK) 13 cells; (ii) the expression of cytotoxin associated gene (cagA), by polymerase chain reaction; and (iii) motility on a semi-solid plate. Positivity for VT production by H. pylori strains isolated from patients with chronic gastritis, gastric ulcer, duodenal ulcer, gastric cancer, and remnant gastritis, was 100%, 89%, 92%, 100%, and 60%, respectively. There was no significant difference in the incidence of positivity for cagA among the strains isolated from different gastric diseases. Swarming distances, which indicate motility of H. pylori strains, were 12.7, 13.2, 12.8, 16.6 and 9.2mm in strains from chronic gastritis, gastric ulcer, duodenal ulcer, gastric cancer, and remnant gastritis, respectively, with H. pylori isolated from remnant gastritis showing significantly less motility than H. pylori isolates from other diseases. There were no significant differences in VT production and cagA positivity among the H. pylori strains.

Animals↗

PubMed1998

Effects of electromagnetic fields on membrane ion transport of cultured cells.

We have studied the mechanisms of ion transport mediated by Na+/K(+)-pump and Na+,K+,Cl(-)-cotransport pathway of HeLa cells using Rb+ as an analog for K+, and proposed models of binding of ions for the transport pathways. Also, we clarified the relation between ion and water movements in the cells. Based on these findings, we have studied the effects of homogeneous and time-varying magnetic fields on the ion transport activity. The research presented here covers (i) brief explanations of our kinetic studies on the ion transport pathways for promoting understanding of the effects of magnetic fields on the pathways, (ii) our and other reports of the effects of magnetic fields on ion transport systems.

Carrier Proteins↗