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Biomedical subjects

H Yamaguchi

Publications and source records attributed to H Yamaguchi.

At least 541 records · Page 30Linked to original sources
PubMed1997

Partial sequences of large subunit ribosomal DNA of a new yeast species, Trichosporon domesticum and related species.

We determined the partial sequences of large subunit rDNA of a new yeast species, Trichosporon domesticum, which was isolated from the house of a summer-type hypersensitivity pneumonitis patient. Phylogenetically, T. domesticum was positioned in the taxonomic group containing T. montevideense and T. brassicae, which indicated an identical serotype. A phylogenetic relationship among all species of the genus Trichosporon which belong to the basidiomycetous yeast is clarified.

Alveolitis, Extrinsic Allergic↗
PubMed1997

Growth inhibition of Helicobacter pylori by monoclonal antibody to heat-shock protein 60.

The H20mAb recognizing the 60-kilodalton protein, which existed in the outer membrane and was induced by heat shock at 42 C, was established. The molecule recognized with the mAb was a heat-shock protein 60 (HSP60) of Helicobacter pylori. To understand the role of HSP60 on the cell surface of H. pylori, whether or not H20mAb affects the growth of H. pylori was investigated. When bacteria were cultured with H20mAb, growth was markedly inhibited after 24 hr, although an initial 5 hr-incubation with the mAb induced no significant inhibition of H. pylori growth. The 24- and 48 hr growth of the bacteria after washing to remove the mAb at 5 hr was also inhibited though the inhibitory effect was not strong. In electron microscopical analysis, the spots with high electron density in the cytoplasm of the bacteria treated with H20mAb were increased, depending on the length of incubation time from 5 to 24 hr. After 24 hr treatment with H20mAb, bacterial destruction was also observed, indicating bactericidal activity by H20mAb. These results suggest that the HSP60 on the cell surface of H. pylori might have an essential role in the growth of the bacteria.

Amino Acid Sequence↗
PubMed1997

Solitary esophageal metastasis of breast cancer with 15 years' latency: a case report and review of the literature.

A 68-year-old woman with a history of breast and colon cancer at the ages of 48 and 65 years, respectively, who presented with dysphagia is described. An upper gastrointestinal series and endoscopic examination revealed a circumferential stricture without ulceration in the middle-third area of the esophagus. Computed tomography demonstrated a submucosal tumor in the esophageal wall. A biopsy specimen obtained from the mucosa overlying the tumor revealed poorly differentiated adenocarcinoma, suggesting metastasis from the previous breast cancer. Subtotal esophagectomy with reconstruction was performed. Macroscopically, a submucosal tumor measuring 2.0 x 1.7 cm was observed in the resected esophagus. Microscopic examination revealed poorly differentiated adenocarcinoma, which was quite similar histologically to the breast cancer resected 15 years previously. Enzyme immunoassay and immunohistochemical analyses of the resected tumor revealed positivity for both estrogen and progesterone receptor, confirming the diagnosis of a metastatic cancer from the previous breast tumor.

Adenocarcinoma↗
PubMed1997

Augmented inhibition of growth of Candida albicans by neutrophils in the presence of lactoferrin.

The combined inhibitory effects of neutrophils and lactoferrins on the growth of Candida albicans were examined. Murine or human neutrophils partially inhibited growth of C. albicans when cultured with C. albicans in vitro. The growth inhibition was augmented by a combination of neutrophils and more than 30 microg/ml of bovine lactoferrin or 1 microg/ml of human lactoferrin, concentrations less than 1/10-1/200 their inhibiting concentrations when used alone. The inhibition of C. albicans was also enhanced by combination of neutrophils and bovine apolactoferrin or iron-bound holo-lactoferrin, but not by transferrin. Combination effects of neutrophils and lactoferrin were also observed in a condition where there was no contact between neutrophils and Candida cells. These results suggest that neutrophils inhibit the growth of C. albicans regardless of whether there is direct contact between them and Candida cells: neutrophil growth inhibition effects were augmented in the presence of a physiological concentration of lactoferrin, perhaps through some action of lactoferrin other than chelation of ferric ion.

Animals↗
PubMed1997

Clinical application and effectiveness of low-density lipoprotein apheresis in the treatment of coronary artery disease.

The Low-Density Lipoprotein Apheresis Coronary Atherosclerosis Prospective Study (L-CAPS) examined whether or not combined low-density lipoprotein (LDL) apheresis and drug therapy apheresis could induce the regression of coronary atherosclerotic lesions in patients with familial hypercholesterolemia. Twenty-eight patients treated with LDL apheresis and drugs and 11 patients treated with drugs alone underwent sequential coronary angiography 2.5 years apart. The frequency of cases with regression or no change was significantly higher for the apheresis group than for the control group (p = 0.004). The LDL apheresis Angioplasty Restenosis Trial (LART) investigated the hypothesis that high plasma lipoprotein (a) (Lp[a]) levels were associated with increased incidences of restenosis after coronary angioplasty. Two days before and 5 days after angioplasty, 66 patients underwent LDL apheresis. The restenosis rates were 21% in the 42 patients whose Lp(a) levels were reduced > or = 50% and 50% in the 24 patients whose Lp(a) levels were reduced < 50% (p < 0.05). LDL apheresis is effective in the prevention of the progression of coronary atherosclerosis. Its potential application in restenosis prevention should be further investigated.

Angioplasty, Balloon, Coronary↗
PubMed1997

Study of the effective dose of a topical antifungal agent, omoconazole nitrate, on the basis of percutaneous pharmacokinetics in guinea-pigs and mice.

The clinically useful optimum dose of omoconazole nitrate, a topical antifungal agent, has been examined by analysing the percutaneous pharmacokinetics of the drug to assess its pharmacological activity in an in-vivo study. Creams containing omoconazole nitrate were prepared on a pilot basis. The therapeutic effect of the omoconazole nitrate creams was examined in an in-vivo pharmacological dermatophytosis infection model in guinea-pigs. Creams containing 0.25% or higher concentrations of omoconazole nitrate resulted in significant inhibition compared with no treatment and with vehicle-treated controls. In the mycological examination no growth of dermatophytes was observed for creams containing 1% or higher concentrations. In an in-vitro hairless mouse skin-permeability test a non-linear least squares program based on a fast inverse Laplace transform algorithm was used to calculate the partition and diffusion parameters of omoconazole nitrate in the stratum corneum and viable epidermis. The time-course of drug concentrations in the skin of the guinea-pig, estimated on the basis of these parameters, led to predictions that percutaneous drug concentrations on the guinea-pig would require 10 or more days to reach equilibrium in the skin; that drug concentrations in the corneum-viable epidermis border, where dermatophytes are considered to grow, would exceed the minimum effective concentration when 0.1% higher concentration creams were used; and that for binding to keratin drug concentrations would reach the practical minimum effective concentration when creams containing 0.5% or more omoconazole nitrate were used. These results show that partition and diffusion parameters obtained from in-vitro skin permeation studies can be used to predict in-vivo percutaneous pharmacokinetics and to estimate therapeutically effective concentrations.

Administration, Topical↗
PubMed1997

Aspergillus endocarditis in a leukemia patient diagnosed by a PCR assay.

A patient in a blastic phase of chronic myelocytic leukemia developed multiple arterial emboli that originated from mitral valve vegetation. The diagnosis of infective endocarditis was not confirmed because blood cultures, serological assays and other examinations detected no pathogens. He died of intracranial hemorrhage after thrombolytic manipulation for embolization of the abdominal aorta and an autopsy was performed. Polymerase chain reaction analysis and Southern blot analysis of tissues from the mitral valve revealed Aspergillus species as the cause of the endocarditis, although none of the tissue specimens were culture-positive. These molecular analyses will be useful in the diagnosis of various types of Aspergillus infections.

Aspergillosis↗
PubMed1997

[Trial for isolation of Helicobacter pylori form fecal specimen by immunomagnetic beads separation].

In order to clarify the possibility of feco-oral transmission of Helicobacter pylori, we have employed an immunomagnetic beads (IMB) separation technique and tried to isolate H. pylori from fecal samples. Microaerophilic cultivation and PCR of H. pylori were positive when H. pylori (10(3) cfu) was suspended in Hanks' balanced salt solution (HBSS) for the IMB separation technique. In contrast, when a lower number of H. pylori (10(2) cfu) was suspended in HBSS, 2nd PCR was positive but cultivation was negative. After IMB separation technique from fecal sample containing H. pylori (2 x 10(4) cfu), 20 cfu of H. pylori was recovered by culture. In this case, 1st PCR was negative but 2nd PCR was positive. From a fecal sample of a patient infected with H. pylori, H. pylori was detected only by combination of IMB separation and PCR, although H. pylori was not recovered by culture. These results indicate that IMB separation technique followed by cultivation or PCR would be useful for estimation of the presence of H. pylori fecal samples.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

Fungicidal action of aureobasidin A, a cyclic depsipeptide antifungal antibiotic, against Saccharomyces cerevisiae.

Aureobasidin A, an antifungal antibiotic inhibiting a wide range of pathogenic fungi, is lethal for growing cells of susceptible fungi. We did cytological studies on the mechanism of its fungicidal action against Saccharomyces cerevisiae. When cultures were treated with 5.0 micrograms of aureobasidin A per ml, the numbers of viable cells started to decrease after 2 to 3 h of incubation, and most cells had lost viability after 5 to 6 h. When cell death in the treated cultures began, amino acids released by the cells could be detected, indicating disruption of the cell membrane. The proportion of cells with a single small bud or two or more buds increased as the population of viable cells decreased. Most such cells had the DNA content of cells in the G2 phase of the cell cycle, suggesting that the drug inhibited some cellular process involved in normal bud growth but did not affect DNA replication. Disruption of actin assembly was found in many cells treated for 2 to 3 h, as was chitin delocalization. The results suggest that aureobasidin A has a previously unknown mechanism of fungicidal action toward S. cerevisiae. It causes aberrant actin assembly, inhibiting the normal budding process and leading to cell death, probably through destruction of membrane integrity.

Actins↗
PubMed1997

Combined treatment with C1 esterase inhibitor and antithrombin III improves survival in severe acute experimental pancreatitis.

BACKGROUND: Patients with severe acute pancreatitis die of complications closely related to the systemic activation of protease cascades. AIM: To examine the effects of human C1 esterase inhibitor (C1 INH) and antithrombin III (AT III) on two experimental models of acute pancreatitis. METHODS: Oedematous pancreatitis was induced by continuous intravenous infusion of caerulein and haemorrhagic pancreatitis by retrograde injection of sodium taurocholate into the biliopancreatic duct. C1 INH and AT III were given intravenously, either before or after the induction of pancreatitis. Treatment with C1 INH and AT III had no beneficial effect on oedematous pancreatitis. On the other hand, combined C1 INH and AT III therapy improved the survival in haemorrhagic pancreatitis compared with treatment with human serum albumin. This reduction in mortality was found regardless of whether the treatment was given prophylactically or therapeutically. CONCLUSIONS: Treatment with C1 INH and AT III represents a promising therapeutic concept for patients with severe haemorrhagic pancreatitis.

Acute Disease↗
PubMed1997

New mechanoenergetic evaluation of left ventricular contractility in in situ rat hearts.

We recorded a series of ejecting left ventricular (LV) pressure (P)-volume (V) loops of in situ rat hearts during a gradual ascending aortic occlusion. The end-systolic (ES) P-V relationship (ESPVR) was upward convex curvilinear regardless of LV contractility. The ESPVR was shifted upward in an enhanced contractility by dobutamine and downward in a depressed contractility by propranolol; ESP at a midrange V of 0.1 ml/g LV on each ESPVR increased from 131 +/- 11 to 192 +/- 17 mmHg and decreased from 136 +/- 10 to 110 +/- 7 mmHg, respectively. Furthermore, we obtained an upward concave curvilinear pressure-volume area (PVA; a measure of total mechanical energy)-V (preload) relationship to assess LV work capability in each contractility. This relationship also shifted upward in enhanced contractility and downward in depressed contractility; the PVA at midrange V increased from 7.9 +/- 1.2 to 12.3 +/- 1.5 mmHg. ml.beat-1.g-1 and decreased from 8.2 +/- 0.9 to 6.4 +/- 0.8 mmHg.ml.beat-1.g-1. We conclude that the heights of the ESPVR and PVA-V relationship curves can evaluate LV contractility mechanoenergetically.

Animals↗
PubMed1997

Dual effects of endothelins on the muscarinic K+ current in guinea pig atrial cells.

Effects of endothelins (ETs) on the acetylcholine receptor-operated K+ current (I(KACh)) were examined in isolated guinea pig atrial cells using patch-clamp techniques. ET-1 or ET-3 produced a transient activation of I(KACh) in atrial cells held at -40 mV. When I(KACh) was preactivated by 1 microM carbachol, however, both ETs produced a transient potentiation followed by a sustained inhibition of the current. When I(KACh) was maximally activated by 10 microM carbachol or 100 microM adenosine, these ETs produced only a sustained inhibition of the I(KACh). Their inhibitory effects on the preactivated I(KACh) were concentration dependent, and the half-maximal effective concentrations were 314 pM for ET-1 and 1.13 nM for ET-3. The inhibitory effect of ET-1 was antagonized by BQ-485, a specific ET(A) receptor antagonist, but not by BQ-788, a specific ET(B) receptor antagonist, indicating that the ET-1 effect is mediated by ET(A) receptors. On the other hand, the inhibitory effect of ET-3 was antagonized by BQ-788 and more effectively by BQ-485, suggesting the involvement of "atypical" ET receptors. Both ETs partly reversed the carbachol-induced shortening of the action potential recorded in the current-clamp mode. Inhibitory effects of ET-1 and ET-3 on the preactivated I(KACh) may contribute to the positive inotropic and chronotropic effects of ETs in atrial tissues.

Acetylcholine↗
PubMed1997

A 5'-splice site mutation in the cytochrome P450 steroid 17alpha-hydroxylase gene in 17alpha-hydroxylase deficiency.

17alpha-Hydroxylase deficiency (17OHD) is an autosomal recessive disorder that produces an excess of mineralocorticoids and sexual differentiation abnormalities. Using DNA sequencing analysis of the 17alpha-hydroxylase (CYP17) gene from a Japanese patient with 17OHD, we identified a new type of genetic abnormality in this disease, a G to A transition at position +5 in the splice donor site of intron 7 of the CYP17 gene. In vitro expression analysis of an allelic minigene that consists of exons 6-8 of the patient's CYP17 gene showed that the transition causes the skipping of exon 7. This exon skipping alters the translational reading frame of exon 8 and introduces a premature stop codon (TAA) at amino acid position 410 proximal to the heme iron-binding site essential for the enzymatic activity of CYP17. Restriction enzyme analysis showed that the patient is homozygous for the mutated CYP17 gene, and the parents are heterozygotes. This is the first reported patient with 17OHD caused by the splice site mutation in the CYP17 gene.

Adrenal Hyperplasia, Congenital↗
PubMed1997

Effects of noradrenaline on GnRH-secreting immortalized hypothalamic (GT1-7) neurons.

Noradrenaline (NA) is one of the most important neurotransmitters involved in the regulation of gonadotropin-releasing hormone (GnRH) secretion. In this study, the effects of NA on GnRH secretion, intracellular Ca2+ concentrations ([Ca2+]i), and membrane potentials were investigated in immortalized hypothalamic neurons (GT1-7) to determine the direct effects of NA on GnRH cells. Cells were perfused in a plastic minicolumn, and GnRH concentrations of the effluents were measured. NA increased the release of GnRH in a dose-dependent manner. Cells were loaded with a 4 microM Fura 2-AM, and the ratio of the intensities of fluorescent emission at 510 nm with excitation at 340 and 380 nm was calculated at 100-ms intervals. NA increased the [Ca2+]i responses of single GnRH cells dose-dependently. The NA-induced [Ca2+]i increase was attenuated in the absence of extracellular calcium and was blocked by the beta-adrenergic antagonist propranolol, but not by the alpha-adrenergic antagonist phentolamine. The cell membrane potential was recorded with a whole-cell patch clamp amplifier with glass-electrodes. NA induced membrane depolarization under current-clamp conditions. The depolarization was also inhibited by propranolol, but not by phentolamine. The results show that NA directly affects the membrane potential of GT1-7 cells via beta-adrenergic receptors and induces Ca2+ mobilization; these effects stimulate GnRH secretion.

Adrenergic alpha-Agonists↗
PubMed1997

Safety and efficacy of oral flecainide acetate in patients with cardiac arrhythmias.

We retrospectively studied the clinical efficacy and safety of oral flecainide in 38 patients with symptomatic arrhythmias. Patients received 100 to 200 mg daily of flecainide for a mean of 25 months (range 8 to 50 months). All patients had normal cardiac function. Paroxysmal atrial fibrillation (PAF) was observed in 29 patients (76%). Other forms of arrhythmia included paroxysmal atrial flutter, seen in 3 patients (8%); premature atrial contraction and ventricular premature contraction, each seen in 2 patients (5%); and supraventricular tachycardia and ventricular tachycardia, each seen in 1 patient (3%). A complete response was obtained in 15 (52%) of 29 patients with PAF and a partial response in 8 patients (27%). The remaining 6 patients (21%) showed no response. A complete response was also obtained in 7 of 9 patients with other forms of arrhythmia. There were no differences in cardiac function and ECG parameters before and after treatment. Flecainide was withdrawn in 4 patients due to the development of electrocardiographic abnormalities. Three of these patients showed an atrial proarrhythmic effect. Abnormal ST elevations in the precordial leads were observed in 1 patient who received 200 mg of flecainide daily. In conclusion, flecainide was effective treatment for supraventricular and ventricular arrhythmias, but attention must be paid to the drug's potential proarrhythmic adverse effects.

Administration, Oral↗
PubMed1997

Effects of irradiation of an erbium:YAG laser on root surfaces.

The application of erbium:YAG laser (Er:YAG) irradiation has been investigated for periodontal therapy. The purpose of this study was to evaluate the effects of Er:YAG laser irradiation on root surfaces using a scanning electron microscope (SEM) and to determine the laser's ability to remove lipopolysaccharides (LPS). Infrared spectrophotometry was used to investigate the effects of the laser on LPS applied to root dentin pellets. Premolars extracted for orthodontic reasons were prepared for this study. The crowns were resected below the cemento-enamel junction, longitudinally sectioned, and the contents of the pulp chamber were removed. Then 15 root tips (5 x 5 x 1 mm) were classified into 3 groups of 5 each as follows: group 1, tips without any treatment; group 2, planed tips with the cement layers left untouched; and group 3, planed until the dentin surface was disclosed. The center of each specimen was used as the experimental irradiated area and the peripheral area served as a control. The quantity of vapor delivered by Er:YAG laser was highly increased, and the irradiated areas displayed little morphogenetic changes. The lyophilized sample LPS 0111 B4 from E. coli was then mixed with potassium bromide and pressed into a tablet, which was examined at 4,000-650 Kayser. The lyophilized LPS had a peak at 2.94 microns. LPS on the root dentin pellets was cleared away as much as possible by 150 washings in pyrogen-free water using an ultrasonic cleaner. Five microliters of 24 EU LPS solution was dropped on the root dentin pellets, which were then irradiated by the Er:YAG laser, and washed using the ultrasonic cleaner in pyrogen-free water. The amount of the extracted LPS solution was determined by spectrophotometer at 405 nm. The Er:YAG laser could remove 83.1% of the LPS. This study suggests that Er:YAG laser irradiation might be useful for root conditioning in periodontal therapy. However, clinical testing is necessary to establish what, if any, utility the Er:YAG laser has as a part of periodontal therapy.

Aluminum Silicates↗
PubMed1997

Acute lymphoblastic leukemia with isolated adrenocorticotropic hormone deficiency.

A 57-year-old female was admitted to our hospital because of Philadelphia chromosome (Ph)-positive acute lymphoblastic leukemia (ALL). On admission, disturbance of consciousness and hyponatremia were recognized. The patient's endocrinological data showed low levels of adrenocorticotropic hormone (ACTH) (less than 5 pg/ml) and cortisol (5.9 microg/dl). Other anterior pituitary hormones were normal. Plasma ACTH and cortisol did not respond to the corticotropin releasing factor (CRF) test. A diagnosis of isolated ACTH deficiency was made. This is a rare case of isolated ACTH deficiency complicated with hematological malignancies.

Adrenocorticotropic Hormone↗