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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 271 records · Page 15Linked to original sources
PubMed1996

A case report of rectal schwannoma.

We experienced a case of rectal schwannoma which was diagnosed before surgery. In this paper we have described this rare case and have discussed a number of similar cases reported in the literature.

Aged↗
PubMed1996

Immunohistochemical localization of vascular endothelial growth factor in esophageal cancer.

We have studied the expression of vascular endothelial growth factor (VEGF) in esophageal cancer using immunohistochemistry. A total of 101 specimens of esophageal cancer tissue were fixed by formalin, embeded in paraffin wax, and examined in 3 microns sections by avidin-biotin peroxidase complex method. VEGF was noted in the cytoplasm of normal esophageal glandular cells, monocyte-macrophages, squamous carcinoma cells and of the vascular endothelial cells themselves. VEGF expression by monocyte-macrophages was observed in all cases, in contrast the incidence of VEGF expression in the tumor cells was relatively low at 26.7% of all specimens. However, in the cases where the tumor cells were positive for VEGF, it was discovered that the main source of the VEGF production was the tumor cells themselves. In the cases with proper mucosal invasion the incidence of VEGF expression by the tumor cells was quite low at 7.6%. However, when the tumor invaded the submucosal layer the expression increased to 33.3%. There was also a significant correlation in those with the submucosal invasion between the expression of VEGF in the tumor cells and that VEGF may play an important role in tumor progression and in the angiogenesis via auto-crine and para-crine mechanisms in esophageal cancer.

Endothelial Growth Factors↗
PubMed1996

Uptake of tetracycline in otoconia of the guinea pig.

Calcium ion turnover in the otoconia of adult guinea pigs was investigated by observing the uptake of tetracycline. Oral administration of tetracycline resulted in the deposition of tetracycline (fluorescence) on the outer surface of otoconia, indicating the occurrence of dynamic exchange and/or uptake of calcium ions in the otoconia. Prolonged administration of tetracycline induced with fluorescence deposition in the central portion as well as on the surface of the otoconia. These findings suggest the occurrence of neogenesis, regeneration and/or growth of otoconia even in adult animals.

Animals↗
PubMed1996

Incorporation of tetracycline into otoconia of the guinea-pig following streptomycin intoxication.

The effects of streptomycin on the calcium ion turnover into otoconia of adult guinea-pigs investigated by the use of tetracycline. The oral administration of tetracycline induced the deposition of tetracycline (fluorescence) on the outer surface of otoconia indicating the existence of dynamic exchange and/or uptake of calcium ions in the otoconia. The significant finding is that streptomycin specifically interfered with calcium uptake into the otoconia which indicated that the decrease in calcium uptake caused by streptomycin may be closely related to the loss of otoconia as well as to a decrease in the calcium contents of otoconia. The decrease in calcium incorporation into otoconia caused by streptomycin was recovered within 6 weeks after the last injection of streptomycin. The number of otoconia with fluorescence in the central portion as well as their outer surface was increased. It is therefore suggested that the recovery of calcium uptake as well as new otoconial regeneration may play an important role for the recovery from loss of otoconia.

Animals↗
PubMed1996

Pharmacological characterization of endothelin receptors in the rabbit iris sphincter muscle: suggestion for the presence of atypical receptors.

Pharmacological profiles of endothelin (ET) receptors in the isolated rabbit iris sphincter were characterized. ET isopeptides caused dose-dependent contraction of the preparation. The respective EC50 values for ET-1, ET-2 and ET-3 were 39.4, 58.0 and 84.3 nM, so that ET-1 was twice as potent as ET-3. Sarafotoxin (SRTX) -b, an ET(A)/ET(B) non-selective agonist, caused very potent contraction with an EC50 of 1.13 nM. However, selective ET(B) receptor agonists SRTX-c and IRL 1620 showed no contractile activity up to 1 microM. BQ-123, a selective ET(A) receptor antagonist, shifted the dose-response curves of ET isopeptides to the right. The pA2 value for ET-1 was 5.52 with a slope of 1.06, which is not different from unity, and the pK(B) value for ET-2 was 5.06. Interestingly, very low doses of BQ-123 antagonized responses to ET-3 and SRTX-b, with a Schild plot slope of approximately 0.7 which is significantly different from unity, suggesting receptor heterogeneity. The abscissal intercepts of the Schild plots were -9.29 for ET-3 and -8.53 for SRTX-b. FR 139317, another ET(A) receptor antagonist, also preferentially antagonized responses to ET-3. RES-701-1, a selective ET(B) receptor antagonist, did not shift dose-response curves for ET-1 and ET-3. These results suggest that ET receptors in the rabbit iris sphincter muscle cannot be classified into the ET(A), ET(B) or ET(C) receptor subtypes, so far established. When compared to the established receptor subtypes, ET receptors in this preparation were quite different from the ET(B) receptor, but apparently showed a pharmacological profile most similar to the ET(A) receptor, suggesting the presence of heterogeneous and atypical ET(A) receptors.

Animals↗
PubMed1996

Calcitonin gene-related peptide induced relaxation of the rabbit iris dilator muscle.

Calcitonin gene-related peptide (CGRP) and Substance P (SP) -immunoreactive nerves have been found in the anterior uvea of various mammalian species. Although SP is known to play a major role in control of pupil motility in rabbits, little is known about the effect of CGRP on the iris smooth muscles. We isolated iris sphincter and dilator muscles from rabbit eyes and investigated the mechanical responses and intracellular cyclic AMP (cAMP) levels in these muscles. CGRP (up to 0.1 microM) had no effect on either the resting muscle tone or the amplitude of contraction evoked by field stimulation of the sphincter. On the other hand, CGRP (0.1 microM) relaxed dilator muscle which had been pre-contracted by phenylephrine and reduced the amplitude of contraction evoked by field stimulation. These responses were antagonized by CGRP (8-37), a CGRP antagonist. The phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (IBMX), dose-dependently inhibited the contraction evoked by field stimulation. However, 3 microM IBMX had no effect on CGRP inhibition of twitch contraction in this preparation. CGRP had little effect on cAMP production in dilator muscle either with or without IBMX. In conclusion, the miosis which occurs during an ocular inflammatory response, when both CGRP and SP are thought to be released from terminals of sensory neurons, results from CGRP relaxation of the dilator and from the strong contractile effect of SP on the sphincter. Adenylate cyclase activation does not seem to be involved in the relaxant effect of CGRP on the dilator.

1-Methyl-3-isobutylxanthine↗
PubMed1996

[Transitional cell carcinoma of the renal pelvis with cystic formation: a case report].

A 75-year-old man consulted our hospital complaining of gross hematuria. Retrograde pyelography revealed a filling defect and deformity of the upper calix of the left kidney. Abdominal echography and computed tomography revealed a left renal cystic tumor with irregular wall thickness measuring 7 by 5 cm. As left renal pelvic tumor or left renal cell carcinoma was suspected, left total nephroureterectomy was performed. Macroscopically, the cystic tumor contained a papillary tumor connected to the renal pelvis and histopathological diagnosis was grade 1 transitional cell carcinoma. Cystic formation caused by obstruction of the upper calix was suspected. After adjuvant chemotherapy, he has been well without recurrence or metastasis for 19 months after the operation. This is the 15th case of renal pelvic tumors with cystic formation including tumors in the pyelocaliceal diverticulum reported in Japan.

Aged↗
PubMed1996

[Clinical study of a macrolide antibiotic, azithromycin, in pediatric patients].

Azithromycin (AZM), 10% fine granules or 100 mg capsules, were given orally to 27 children with various pediatric infections. The results of the study are shown below. 1. Pharmacokinetic investigation. We studied plasma and urinary concentrations after 100 mg AZM capsules were given. One patient received 8.3 mg/kg of AZM once a day for 3 days, and AZM concentration in plasma was 0.033 microgram/ml 48 hours after the final dosing. Doses of 8.3 and 12.5 mg/kg body weight of AZM were respectively given to two patients once daily for 3 days. As a result, AZM concentrations in urine during a period between 96 and 120 hours post-dosing were 1.67 and 4.53 micrograms/ml, respectively, and urinary excretion rate in 120 hours after the first dosing was 10.54% in the patient that was given 12.5 mg/kg. 2. Clinical investigation. Clinical efficacies were examined in 24 patients. Excellent results were obtained in 7 patients, good results in 14 patients, hence the clinical efficacy rate was 87.5%. Bacteriologically, Haemophilus influenzae strains isolates from 2 patients were eradicated in 1 and decreased in the other. Safety was evaluated in 26 patients. An adverse reaction was observed in 1 patient (urticaria). Abnormal laboratory test results were observed in 2 patients, decreased WBC in 1 and elevation of eosinophils in the other. The above results suggest that AZM is a useful oral antibiotic for pediatric patients with infection with susceptible organisms.

Adolescent↗
PubMed1996

[Pharmacokinetic and clinical studies on azithromycin in children].

Azithromycin (AZM) is a new oral macrolide antibiotic drug. AZM either in 10% fine granules form or in 100 mg capsule form was studied for its pharmacokinetics and treatment efficacy in pediatric patients with various infections. 1. Pharmacokinetics. Plasma and urine samples were collected from four patients with pharyngitis and post-dosing drug levels were determined. The drug was given once daily at 10 mg/kg body weight for 3 days. The drug concentrations found in plasma at 96 hours after the first dosing (48 hours after the final dosing) lay in a range of 0.02 and 0.04 microgram/ml and in urine at 120 hours after the first dosing (72 hours after the final dosing) in a range between 3.2 and 7.7 micrograms/ml. AZM was found in two patients but no effect was observed on blood levels of theophylline determined between 48 and 96 hours after the first dosing in the treatment of underlying bronchial asthma. 2. Clinical study results. Clinical studies of AZM was carried out in 25 pediatric patients with bacterial infections that mainly affected the respiratory tract. The patients received either 10% fine granules at 10 or 20 mg/ kg body weight or 100 mg capsules at 10 mg/kg body weight once daily over 3 to 6 days. The drug was found markedly effective in six patients, moderately effective in thirteen patients, while the investigators could not assess the drug efficacy in six patients. Although no side effect was reported in the study, two patients experienced slight decrease in WBC.

Adolescent↗
PubMed1995

Involvement of PIM-1 in DNA fragmentation in mouse NS-1-derived cells.

In several cell lines derived from mouse NS-1 myeloma cells, internucleosomal fragmentation of chromosomal DNA, a hallmark of apoptosis, was continuously observed. Approximately 15-20% of the cells died when isolated in a 96-well plate, and the surviving cells contained fragmented DNA ('ladder'). Among a variety of genes so far reported to be related to apoptosis, only Pim-1 was expressed at an elevated level in the NS-1 hybridomas as compared in a control myeloma cell line without 'ladder'. Transfection of a Pim-1 expression vector to a 'ladder'-non-producing myeloma line yielded similar internucleosomal DNA fragmentation. The results hence suggested that Pim-1 activates endonucleases responsible for DNA fragmentation during apoptosis and/or repress DNA repair systems to restore fragmented DNA.

Animals↗
PubMed1995

Mutation frequency of the p16/CDKN2 gene in primary cancers in the upper digestive tract.

We report a highly frequent homozygous deletion of the p16/CDKN2 gene in the esophageal cancer cell line and a relatively high frequency of homozygous deletion in gastric cancer cell lines. In contrast, in primary esophageal carcinomas, mutation frequency of the p16/CDKN2 gene has been controversial (0, 21, and 52% previously reported), and no reports are available for the mutation frequency of this gene in surgical specimens of gastric carcinomas. Here we report that four (16%) of 25 primary esophageal squamous cell carcinomas were found to be mutated, one in exon 1 and three in exon 2, and that no mutations were observed in 19 surgical specimens of gastric adenocarcinomas. This is the first report showing the absence or quite low frequency of mutation in surgical specimens of gastric carcinomas.

Base Sequence↗
PubMed1995

Imaging of single fluorescent molecules and individual ATP turnovers by single myosin molecules in aqueous solution.

Visualization of single actin filaments by fluorescence microscopy led to the development of new in vitro assays for analysing actomyosin-based motility at the molecular level. The ability to manipulate actin filaments with a microneedle or an optical trap combined with position-sensitive detectors has enabled direct measurements of nanometre displacements and piconewton forces exerted by individual myosin molecules. To elucidate how myosin generates movement, it is necessary to understand how ATP hydrolysis is coupled to mechanical work at the level of the single molecule. But the most sensitive microscopic ATPase assay available still requires over 1,000 myosins. To enhance the sensitivity of such assays, we have refined epifluorescence and total internal reflection microscopies to visualize single fluorescent dye molecules. We report here that this approach can be used directly to image single fluorescently labelled myosin molecules and detect individual ATP turnover reactions. In contrast to previously reported single fluorescent molecule imaging methods, which used specimens immobilized on an air-dried surface, our method allows video-rate imaging of single molecules in aqueous solution, and hence can be applied to the study of many types of enzymes and biomolecules.

Adenosine Triphosphate↗