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H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 577 records · Page 32Linked to original sources
PubMed1997

[The in vitro antifungal activities of fluconazole against pathogenic yeasts recently isolated from clinical specimens].

The emergence of Candida albicans resistance to azole antifungal agents have been reported in the U. S. and Europe. We examined the in vitro antifungal activities of fluconazole against clinical isolates collected by seven investigators in three years to examine if a tendency existed toward the development of azole-resistance among fungal isolates in Japan. The following results were obtained: 1. Sensitivities to fluconazole (FLCZ) were determined for yeast-like fungi, including 113 strains isolated in 1993, 149 strains isolated in 1994 and 205 strains isolated in 1995. No significant differences in sensitivities in the three years were detected. 2. Minimum inhibitory concentrations of FLCZ were 0.1-0.78 microgram/ml for C. albicans and 3.13-25 micrograms/ml for C. glabrata. Strains with 25 micrograms/ml of FLCZ's MIC were detected; two strains of C. krusei and one strain each of C. krusei, Trichospron beigelii and Hansenula anomala. No strains with higher than 50 micrograms/ml MIC of FLCZ were detected. 3. In vitro activities of FLCZ were compared between clinical strains isolated between 1993 and 1995 and clinical strains isolated before the marketing of FLCZ (up to December 1987) or clinical yeasts isolated between 1991 and 1992. No significant differences were observed, suggesting that no tendency existed toward azole resistance among fungal strains examined.

Antifungal Agents↗
PubMed1997

[Comparative studies of airway deposition of 99mTc-DTPA aerosol particles among 4 different nebulizers by pulmonary scintillation method].

The inhalation therapy is one of the important treatment of bronchial asthma. The effectiveness of the therapy, however, is different depending on the size of particles produced by each inhalation equipment. Therefore, we have tried to clarify the relationship between the size of inhaled particles and the deposition rate in the lung by using different types of equipment. Four different equipments, Nishou, Pari-Boy, Pari-Master and Atom Soniclizer 905 were used. 99mTc-DTPA was dissolved in physiological saline and was inhaled for evaluation of "deposition" rate in the lung. The deposition rates by Nishou, Pari-Boy, Pari-Master and Atom Soniclizer 905 were 10.4 +/- 5.8%, 27.5 +/- 14.5%, 28.5 +/- 6.5%, and 31.1 +/- 6.8%, respectively. Most of 99mTc-DTPA inhaled was observed in oral cavity. The deposition in the lung by Nishou was significantly reduced compared to other three nebulizers. Those three were evaluated as appropriate equipments for the treatment. The average size of particles in an airsol by those three equipments was less than 5 microns. The study suggests that the size of "particles" in an airsol is very important factor for the inhalation therapy.

Adult↗
PubMed1997

Correlation between antifungal activity and hydrophobicity of imidazole antifungal agents.

To examine the effects of the affinity of antifungal imidazole agents to cell membranes on the in vitro antifungal activity, the correlation between antifungal activity and hydrophobicity of these drugs was investigated. The capacity factor (k') in HPLC was used as a parameter of hydrophobicity, and the minimum inhibitory concentration (MIC) as a parameter of antifungal activity. Consequently, a significant portion correlation was noted in the case of Candida albicans. However, no obvious correlation was noted for Trichophyton mentagrophytes and Trichophyton rubrum. Therefore, the mechanism of action of imidazole derivatives for Candida albicans was considered to mainly consist in the membrane action.

Antifungal Agents↗
PubMed1997

[Flow cytometric quantification of numerical chromosome aberrations in non-small cell lung carcinomas using formalin-fixed paraffin-embedded tissue].

Fluorescence in situ hybridization with biotinylated repetitive DNA probe specific for the centromeric region of chromosome 17 (p17H8: Oncor) was applied to suspended nuclei which were isolated by Shutte's method from formalin-fixed paraffin-embedded tissue. The tissues were obtained from surgically resected specimens from nine patients with non-small cell lung carcinoma. The isolated nuclei were prepared with 0.05% pepsin/0.1NHCl for 15 minutes at 37 degrees C. Subsequently, these were immersed in 70% acetic acid for 10 seconds at room temperature. After heat denature with hybridization mixture which contained 3 mu 1 DNA probe for 10 minutesat 70 degrees C, 1 x 10(6) nuclei were incubated overnight at 37 degrees C. After washing with 60% formamide/2 x SSC, the hybridized probes were labeled by FITC conjugated avidin. A number of centromeric signals of chromosome 17 wasevaluated by fluorescence microscopy (BH-2, Olympus). Furthermore, a probe-related FITC intensity was quantified using flow cytometry (FACScan, Becton Dickinson). As the results, there was good correlation between a relative fluorescence intensity determined by flow cytometry and a relative fluorescence signal by fluorescence microscopy (p < 0.05).

Aged↗
PubMed1997

[Ultrasonographic assessment of carotid atherosclerosis emphasizing the variety of intimal-medial thickness and the relationship with coronary risk factors].

Intimal-medial thickness (IMT) of the extracranial carotid arteries measured by B-mode ultrasonography has been used as a marker of systemic and coronary atherosclerosis. Previous studies have indicated that maximum and mean carotid IMT are significantly correlated with the extent and severity of coronary artery disease (CAD), but the clinical usefulness of these markers is limited because they are neither specific nor sensitive enough to identify patients with or without significant CAD. The correlation of a new IMT marker, variance of IMT, with coronary risk factors and coronary atherosclerosis was investigated in 200 patients who underwent carotid ultrasonography and coronary angiography. IMT was measured in 16 sites of the extracranial carotid arteries for the calculation of mean, maximum and variance of IMT. Univariate analysis showed that these three indexes were significantly correlated with age, serum lipoprotein (a) and hypertension. However, age was correlated weakly with variance of IMT. There were significant gender differences in the mean and maximum IMT but not in the variance. There were also significant correlations of mean IMT with smoking, and maximum and variance of IMT with high-density lipoprotein. Multiple logistic regression analysis in 100 age and sex matched patients indicated that the only significant predictor for CAD in this subgroup was variance of IMT (odds ratio = 1.6). These results indicated that each risk factor causes different morphologic manifestations in the carotid atherosclerotic lesion. Variance of IMT, which represents the irregularity of carotid IMT, was correlated well with CAD and appears to be useful for assessing systemic and coronary atherosclerosis.

Aged↗
PubMed1997

A study of the growth changes in the maxillofacial skeleton of females with reversed occlusion: investigation by means of lateral x-ray cephalogram.

321 females with reversed occlusion from the ages of 6 to 20 were classified into 15 groups according to chronological age, and the changes of maxillofacial skeleton accompanying growth were investigated. Lateral cephalometric roentgenogram before treatment of the subjects were used for analyses and measurements of maxillofacial skeleton and overjet. The cephalometric analysis was standardized on the S-N plane, and 5 angular items and 6 linear distances were examined. The results of the investigation are summarized as follows: (1) angle ANB, the relationship between the upper and lower jaws, deteriorated to a minus degree from the age of 9 and became -3.3 degrees at the age of 14. Skeletal convexity became negative from the same age and was -7.3 degrees at the age of 14. Thus, the abnormal skeletal features progressed in this condition. (2) The Ar-Gn distance measurement gradually increased from the age of 6 to 18. The increase was 16.2 mm from 7 to 12, an increase of 3.2 mm yearly. (3) A high correlation (r = 0.99) was observed between angle ANB and Convexity. As well, a high coefficient of correlation (r = 0.87) was observed between skeletal convexity and soft tissue convexity. The change in soft tissue convexity may occur 3-4 years later than that of skeletal convexity. (4) The growth curve of Ar-Gn became a logistic curve with the point of deflection at the age of 10.87. The growth curves of S-Gn and N-Me became logistic curves in the same way.

Adolescent↗
PubMed1996

Structural basis for activation of human lymphocyte kinase Lck upon tyrosine phosphorylation.

Regulation through phosphorylation is a characteristic of signalling pathways and the lymphocyte kinase Lck (p56lck) both performs phosphorylation and is affected by it. Lck is a Src-family tyrosine kinase expressed in T lymphocytes, where it participates in the cellular immune response. Like all Src homologues, it comprises SH3, SH2 and kinase domains. Lck associates through its distinctive amino-terminal segment with the cytoplasmic tails of either T-cell co-receptor, CD4 or CD8-alpha. Activated Lck phosphorylates T-cell receptor zeta-chains, which then recruit the ZAP70 kinase to promote T-cell activation. Lck is activated by autophosphorylation at Tyr 394 in the activation loop and it is inactive when Tyr 505 near the carboxy terminus is phosphorylated and interacts with its own SH2 domain. Here we report the crystal structure of the Lck tyrosine kinase domain (LCKK) in its activated state at 1.7 A resolution. The structure reveals how a phosphoryl group at Tyr 394 generates a competent active site. Comparisons with other kinase structures indicate that tyrosine phophophorylation and ligand binding may in general elicit two distinct hinge-like movements between the kinase subdomains. From modelling studies, we suggest a basis for inhibition by phosphorylation at Tyr 505.

Binding Sites↗
PubMed1996

An in vitro system for identifying agents capable of changing serum lipoprotein(a) concentration by regulating the transcriptional activity of the apolipoprotein(a) gene promoter.

A high serum concentration of lipoprotein(a) [Lp(a)] is a significant and independent risk factor for cardiovascular disease. We examined the effects of agents on the transcriptional activity of the apolipoprotein(a) [apo(a)] gene promoter and determined whether drugs identified by this assay would affect the serum concentration of Lp(a) in vivo. All-trans-retinoic acid (ATRA) and interleukin-6 increased the transcriptional activity of the apo(a) gene promoter 2.1- and 2.5-fold, respectively, whereas danazol reduced activity to 76% of the control value. Triiodothyronine had no effect on transcriptional activity. Treatment of two acute promyelocytic leukemia patients with ATRA induced maximal 2.7- and 3.2-fold increases in serum Lp(a) concentrations, respectively. Thus, the in vitro luciferase assay system is capable of identifying agents that affect the serum concentration of Lp(a) and thus may prove beneficial in the screening of new drugs for treatment of individuals with high serum Lp(a) concentrations.

Adult↗
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↗
PubMed1996

Crystallization and preliminary X-ray diffraction analysis of two lysinal derivatives of Achromobacter protease I.

Two crystal forms of lysinal derivatives of Achromobacter protease I have been obtained. The first, modified by benzyloxycarbonyl-Val-lysinal crystallizes in the monoclinic space group P2(1) with unit-cell dimensions of a = 39.6, b = 71.2, c = 45.6 A and beta = 98.4 degrees. The second, modified by benzyloxycarbonyl-Leu-Leu-lysinal crystallizes in the orthorhombic space group I222 (or I2(1)2(1)2(1)) with unit-cell dimensions of a = 98.7, b = 102.2 and c = 55.8 A. The space groups and the unit-cell dimensions of the present two lysinal derivatives are different to those of the protease and TLCK- modified one. The space group of the protease is P1 with cell dimensions a = 39.53, b = 40.34, c = 43.92 A, alpha = 114.81, beta = 113.75 and gamma = 74.00 degrees and that of the TLCK-modified one is also P1 with cell dimensions of a = 37.30, b = 42.74, c = 48.02 A, alpha = 120.10, beta = 112.81 and gamma = 68.54 degrees. Diffraction to 1.9 A resolution for the Val-lysinal modified crystal and to 2.2 A resolution for the Leu-Leu-lysinal modified crystal has been observed using a rotating-anode X-ray generator. Full structure determinations of these lysinal-modified protease crystals may lead to an understanding of the molecular basis of enzyme-substrate interactions in the catalytic process of this protease.

Journal Article↗
PubMed1996

Induction of spinal cord neuronal nitric oxide synthase (NOS) after formalin injection in the rat hind paw.

The nitric oxide synthase (NOS) inhibitor L-nitroarginine methyl ester has been found to exhibit antinociceptive activity in a rat model of pain [Kitto, K.F. et al., Neurosci. Lett., 148 (1992) 1-5; Lee, J.H. et al., NeuroReport, 3 (1992) 841-844; Moore, P.K. et al., Br. J. Pharmacol., 102 (1991) 198-202]. We investigated the hypothesis that hind paw injection of formalin increases the number of dorsal horn neuronal nitric oxide synthase (nNOS) containing neurons. Results showed a bilateral increase in the number of nNOS-positive neurons at the L4-5 dorsal horn area following formalin injection. The increase was always greater on the ipsilateral side compared to the contralateral side. This upregulation of nNOS following formalin stimulation of the hind paw suggested that nitric oxide (NO) may play a role in the central mechanism of hyperalgesia that follows peripheral inflammation.

Animals↗
PubMed1996

The whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A.

The crystal structure of bovine heart cytochrome c oxidase at 2.8 A resolution with an R value of 19.9 percent reveals 13 subunits, each different from the other, five phosphatidyl ethanolamines, three phosphatidyl glycerols and two cholates, two hemes A, and three copper, one magnesium, and one zinc. Of 3606 amino acid residues in the dimer, 3560 have been converged to a reasonable structure by refinement. A hydrogen-bonded system, including a propionate of a heme A (heme a), part of peptide backbone, and an imidazole ligand of CuA, could provide an electron transfer pathway between CuA and heme a. Two possible proton pathways for pumping, each spanning from the matrix to the cytosolic surfaces, were identified, including hydrogen bonds, internal cavities likely to contain water molecules, and structures that could form hydrogen bonds with small possible conformational change of amino acid side chains. Possible channels for chemical protons to produce H2O, for removing the produced water, and for O2, respectively, were identified.

Amino Acid Sequence↗
PubMed1996

Application of percutaneous transluminal coronary angioplasty to coronary arterial stenosis in Kawasaki disease.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) has rarely been performed on patients with coronary lesions that result from Kawasaki disease. In this study, we retrospectively evaluated the effectiveness of PTCA in five patients with coronary arterial stenosis that resulted from Kawasaki disease and reviewed previous reports for possible indicators of PTCA effectiveness. METHODS AND RESULTS: Five patients, ranging in age from 2 to 16 years (median 8 years) underwent conventional PTCA for localized stenosis. The lesion targeted for PTCA was located in the middle right coronary artery of three patients and in the left anterior descending artery in two patients. In four of the five patients, PTCA was angiographically effective, with stenosis rates improving from 84 +/- 10% to 33 +/- 11% (P<.05). When the previously reported cases of six similar patients were taken into consideration, the only predictor of successful PTCA seemed to be the time elapsed between the onset of Kawasaki disease and performance of this procedure. CONCLUSIONS: In cases in which patients show significant localized stenosis as a result of Kawasaki disease, PTCA should be attempted within 6 to 8 years of the onset of the disease. Additionally, intravascular ultrasound imaging was found to be a useful tool for evaluating internal morphology before and after PTCA. In older patients with coronary calcification, other alternatives to PTCA, such as the use of a rotablator or an atherectomy catheter, should be considered.

Adolescent↗
PubMed1996

Different carcinogenesis in the gastric remnant after gastrectomy for gastric cancer.

BACKGROUND: The incidence of gastric remnant cancer after surgery for gastric malignancies has been increasing. The interval between previous operations and the diagnosis of gastric remnant cancer, location of cancer development, and histologic type were different from those after surgery for benign diseases. However, very little is known about the reasons for these differences. Patients with gastric cancer already have cancer-related gastric mucosal changes at gastrectomy, and they undergo a wide range of dissection of nerve distribution to the stomach due to lymph node dissection. Therefore, the effects of preliminary administration of a carcinogenic agent and denervation of the gastric mucosa on tumorigenesis in the gastric remnant were investigated. METHODS: Using male Wistar rats, N-methyl-N'-nitro-N-nitroguanidine (MNNG; 50 mg/L) was given in drinking water for 10 weeks. The animals were then assigned into four groups of those undergoing Billroth I (B-I) gastrectomy or Billroth II (B-II) gastrectomy, with and without denervation. Subdiaphragmatic truncal vagotomy was performed in the denervated group. Thirty weeks after gastrectomy, the following investigations were performed: histologic examination and periodic acid-Schiff-Alcian blue (PAS-AB) staining of the gastric mucosa by immunohistochemistry of proliferating cell nuclear antigen (PCNA). RESULTS: In macroscopic findings, the groups undergoing nitrosoguanide (NG) gastrectomy with denervation showed a significant increase in the development of whitish, nodular changes in the gastric body. These changes mainly consisted of intestinal metaplasia in microscopic findings. In the NG gastrectomy group, the cancer developed at a lower rate of incidence at the anastomotic site and in the gastric body (1 of 11 rats and 1 of 11 rats, respectively). Conversely, a higher incidence of cancer development (5 of 13 rats) in the gastric body was observed in the group that underwent NG gastrectomy with denervation. Furthermore, the denervation group showed a significant increase in the PCNA labeling index and a distinct increase in the staining of Alcian blue positive mucin in the mucosa of the gastric body. The cancers that developed in the gastric body showed horizontal growth and were accompanied by intestinal metaplasia. In contrast, the cancers that developed in the gastric stumps showed downward growth, and were always accompanied by adenocystic proliferation, but not intestinal metaplasia. CONCLUSIONS: Different processes of carcinogenesis in the gastric remnant are postulated after the surgery for gastric malignancies. The developed cancer is defined by its location and the gastric mucosal changes that developed at the time of gastrectomy.

Animals↗