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Biomedical subjects

Y Hirano

Publications and source records attributed to Y Hirano.

At least 55 records · Page 3Linked to original sources
PubMed2001

Chondroblastoma of a metacarpal bone mimicking an aneurysmal bone cyst: a case report and a review of the literature.

Chondroblastoma of the metacarpal bone has been extremely rare and only seven cases have been reported in the English literature. Here we reported the eighth case of a chondroblastoma that developed on the first metacarpal bone of the right hand of a 21-year-old man. Radiographs showed an expansile osteolytic lesion with a multilocular appearance. In MR images, the lesion showed low intensity in T1 and high intensity in T2-weighted images with multiple fluid-fluid levels, which are findings resembling those of an aneurysmal bone cyst. From the pathological findings, however, it was recognized as a chondroblastoma with aneurysmal bone cyst-like change. Good clinical results was obtained by the subtotal resection of the metacarpal bone with a columnar-shaped iliac bone graft.

Adult↗
PubMed2001

Determination of traces of cadmium in natural water samples by flow injection on-line preconcentration-graphite furnace atomic absorption spectrometry.

A flow injection on-line preconcentration-graphite furnace atomic absorption spectrometric method was developed for the determination of traces of cadmium in natural water samples. Cadmium in samples was adsorbed on an iminodiacetate-type chelating resin, Muromac A-1 microcolumn (3 mm i.d. and 10 mm long), and then eluted with 2 mol l-1 HNO3. The eluate was introduced into the injection tip of an autosampler. The eluate zone with the highest analyte concentration was injected into the graphite furnace by cooperation of a peristaltic pump and a syringe pump of the autosampler, which were controlled by a programmable controller. The present system was successfully applied to the determination of cadmium in natural water samples. A detection limit of 0.2 ng l-1 was obtained with 12 ml sample loading. The recoveries were 99 and 108% for tap water (4 ml loading) and underground water (12 ml loading), respectively. Analytical results obtained for a river water reference material (JAC-0031, Japan Society for Analytical Chemistry) were close to the reference value.

Cadmium↗
PubMed2001

Identical unitary current amplitude and Ca(2+) block of cardiac Na channel before and during beta-adrenergic stimulation.

We examined the possibility of Ca(2+) permeation through cardiac Na channels ("slip mode conductance") by an analysis of the voltage-dependent block of Na channels by Ca(2+). A Ca(2+) block of Na channels was evident in rat and guinea pig ventricular myocytes during cell-attached single channel recordings with a physiological ionic environment (140 mM Na(+) and 1 to 10 mM Ca(2+) in the pipette solution). Increasing external Ca(2+) concentration ([Ca(2+)](o)) in the pipette solution reduced the unitary current amplitude predominantly at negative potentials. With [Ca(2+)](o) > 1 mM, unitary current amplitude did not increase at potentials negative to -40 mV in spite of augmented driving forces. The application of 5 microM isoproterenol potentiated the single channel activity elicited by depolarizing pulses from the holding potential of -120 mV, indicating that the channels in the patch under examination were modified by protein kinase A (PKA) stimulation. Increased activity was also confirmed with veratridine-modified Na channels, where channel openings were markedly prolonged. In either case, isoproterenol-induced potentiation neither reduced nor altered the properties of Ca(2+) block of cardiac Na channels, as evidenced by the stable unitary current amplitudes at potential levels from -60 to -20 mV. These results indicate that interactions among Na(+), Ca(2+), and the channel molecule were not modified with respect to permeation properties. They therefore argue against the "slip mode" concept of classical cardiac Na channel if a general concept of ion permeation through "multi-ion pores" is applicable to determine the ionic selectivity of Na channels.

Adrenergic beta-Agonists↗
PubMed2001

Controlled release of hepatocyte growth factor from gelatin hydrogels based on hydrogel degradation.

This paper investigates the controlled release of hepatocyte growth factor (HGF) by biodegradable gelatin hydrogels and their HGF-induced angiogenic effect. Hydrogels of different degradabilities were prepared through chemical crosslinking gelatin with varied amounts of glutaraldehyde. When the gelatin hydrogels were radioiodinated and subcutaneously implanted into the back of mice, the remaining radioactivity of the hydrogels decreased with time. However, the remaining period became longer when the concentration of glutaraldehyde used for hydrogel preparation increased. Following implantation of gelatin hydrogels incorporating 125I-labeled HGF, the HGF radioactivity retained in the mouse subcutis for longer time periods as the glutaraldehyde concentration becomes higher. The time profile of HGF remaining in every gelatin hydrogel was in good accordance with that of hydrogel degradation, indicating HGF release as a result of hydrogel biodegradation. The gelatin hydrogel incorporating HGF histologically induced angiogenic change around the implanted hydrogel. Gelatin hydrogels incorporating 5 and 10 microg HGF significantly enhanced the number of capillaries newly formed around the implanted site. This was in marked contrast to free HGF of same dose form and HGF-free, empty gelatin hydrogel. The gelatin hydrogel incorporating HGF induced VEGF around the implanted site. In vitro bioassay revealed that HGF molecules interacting with gelatin, still exhibited the biological activity. The interacted HGF would be released from gelatin hydrogels only when they were degraded to generate water-soluble gelatin fragments. It is possible that the HGF associating gelatin fragments of bioactivating, results in induced angiogenic effect.

Animals↗
PubMed2001

[Contrast agent improves diagnostic value of dobutamine stress echocardiography].

OBJECTIVES: Suboptimal endocardial definition reduces the diagnostic value of stress echocardiography for coronary artery disease, but intravenous infusion of a left ventricular contrast agent (Albunex) may enhance endocardial border delineation and improve the diagnostic value of dobutamine stress echocardiography. METHODS: Fifty-six patients, 38 with myocardial infarction, 16 with angina pectoris and two normal subjects, were enrolled in this study. Dobutamine was infused in scalar doses of 5 to 40 micrograms/kg/min. Intravenous infusion of Albunex (0.15 ml/kg) was administered at rest and during peak dobutamine stress during monitoring of the apical four-chamber view. The left ventricle in the apical four-chamber view was divided into six segments and an endocardial delineation score of 0 to 3 (none to excellent visualization) was given to each segment. RESULTS: Endocardial delineation score was increased after Albunex infusion from 2.0 to 2.3 in the basal-septal, 2.0 to 2.4 in the mid-septal, 1.1 to 1.8 in the apical-septal, 0.7 to 1.2 in the apical-lateral, 0.9 to 1.6 in the mid-lateral, and 1.2 to 1.9 in the basal-lateral segments during peak dobutamine administration. Endocardial border resolution in the lateral wall showed greater improvement than in the septal wall after Albunex infusion. Diagnostic values in the left anterior descending artery territory failed to improve with Albunex infusion (sensitivity 82% to 89%, specificity 94% to 89%, and accuracy 86% to 89%), whereas a higher diagnostic accuracy was noted in the left circumflex artery territory with Albunex compared to without Albunex (sensitivity 63% to 81%, specificity 88% to 98%, and accuracy 80% to 93%, p < 0.05). CONCLUSIONS: Contrast agent improves the diagnostic accuracy of dobutamine stress echocardiography in the left circumflex artery territory.

Aged↗
PubMed2001

[The role of ischemic preconditioning in off-pump CABG: is it really necessary to accomplish scrupulous ischemic preconditioning?].

In an attempt to avoid the deleterious effect of cardiopulmonary bypass, off-pump coronary artery bypass grafting has been rediscovered and spread. We often accomplish the ischemic preconditioning (IP) in off-pump CABG. IP is the phenomenon in which sublethal episode of myocardial ischemia result in increased tolerance to a later, potentially lethal, episode of ischemia. To evaluate the cardioprotective effect of IP and an ATP-sensitive potassium channel (KATP) opener, oxidative radical scavenger, 43 clinical cases were examined. The myocardial tissue oxygen saturation was measured by near-infra red spectroscopy during IP. Twelve cases were subjected to accomplish simple IP (5 min x twice), and 29 cases received pharmacological IP (administrated allopurinol preoperatively and nicorandil intraoperatively; 3 min x once). The result showed that the tissue oxygen of pharmacological IP group is superior to that of simple IP group. The concomitant use of IP and KATP opener, oxidative radical scavenger both ameliorated cardiac dysfunction during the ischemia in anastomotic occlusion of the coronary artery, and improved the postischemic functional recovery. These results suggest that we would be able to decrease both duration and the number of times of IP by using KATP opener and oxidative radical scavenger.

Allopurinol↗
PubMed2001

Comparison of 3 surgical approaches to laparoscopic adrenalectomy: a nonrandomized, background matched analysis.

PURPOSE: To clarify the characteristics of surgical approaches to laparoscopic adrenalectomy we performed background matched analysis of clinical outcomes of the 3 approaches. MATERIALS AND METHODS: From February 1992 to July 2000 we performed 118 laparoscopic adrenalectomies in 115 patients with adrenal tumors. For these operations we used the anterior transperitoneal approach in 46 patients, the lateral transperitoneal approach in 32 and the lateral retroperitoneal approach in 40. RESULTS: To exclude the learning curve effect we eliminated our initial 20 patients treated with the anterior transperitoneal approach. To allow background matching of the 3 groups we also excluded 14 patients with tumors more than 5 cm., 6 who underwent conversion to open surgery and 1 patient who required 5 days of bed rest for retroperitoneal hematoma caused by bleeding from a trocar port. The final analysis included 16, 25 and 36 cases managed via the anterior transperitoneal, lateral transperitoneal and lateral retroperitoneal approach, respectively. Average operative time was significantly shorter for the lateral transperitoneal approach. Postoperative recovery was not significantly different in the lateral transperitoneal and lateral retroperitoneal groups. Postoperative complications included mild paralytic ileus in 2 patients and shoulder tip pain, probably peritoneal irritation due to carbon dioxide insufflation and bowel preparation, in 4 in the transperitoneal groups. Our results imply that the easiest procedure is the lateral transperitoneal approach but the lateral retroperitoneal approach is slightly less invasive. CONCLUSIONS: Although it is important to remember that this study was not a prospective randomized trial and, thus, had from certain biases, we believe that if a tumor is more than 5 cm. and/or the surgeon is not yet skilled in laparoscopic adrenalectomy, the lateral transperitoneal approach is the most suitable method. If the surgeon has performed at least 20 operations, the adrenal tumor is unilateral and the lesion is less than 5 cm., the lateral retroperitoneal approach seems to be more suitable because of its minimally invasive nature. The lateral retroperitoneal approach is also preferred in patients with a history of upper abdominal surgery. With improvements in technique and new instruments the time required for the lateral retroperitoneal approach has been significantly decreased.

Adrenal Gland Neoplasms↗
PubMed2001

Studies on mechanisms of low emetogenicity of YM976, a novel phosphodiesterase type 4 inhibitor.

YM976 is a novel and selective inhibitor of phosphodiesterase type 4 (PDE4) with a different chemical structure from rolipram. Orally administered YM976 showed anti-inflammatory activity (ED(50) = 2.8 mg/kg) similar to rolipram (3.5 mg/kg). On the other hand, the emetogenicity of YM976, one of the main adverse effects of PDE4 inhibitors, was lower (maximal non-emetic dose = 10 mg/kg) than that of rolipram (1 mg/kg). The reasons for this low emetogenicity of YM976 remain unclear, and the present study endeavored to elucidate the mechanisms. Candidates for the possible mechanisms included 1) PDE4 subtype selectivity, 2) binding affinity for HAR-conformation, and 3) brain penetration. YM976 exhibited affinity for high affinity for rolipram-conformation (HAR-conformation) (IC(50) = 2.6 nM) identical to that of rolipram (1.2 nM), and failed to show significant selectivity for the individual PDE4 subtype. These results suggested that neither subtype selectivity nor the affinity for HAR-conformation may be related to the low emetogenicity of YM976. YM976 showed a minor effect on reserpine-induced hypothermia, in contrast to rolipram. To estimate brain penetration, we then measured cAMP contents in peripheral tissues (peritoneal macrophages) and in the brain. YM976 increased the cAMP content of peritoneal macrophages, but caused no significant increase in brain cAMP levels, while rolipram elevated the cAMP content of both tissues at the same dose. In conclusion, YM976 shows an apparent dissociation between its anti-inflammatory effects and emetogenicity, perhaps because of the poor brain penetration.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2001

[Complications of stress echocardiography].

BACKGROUND: Stress echocardiography is an established clinical testing method and is accurate for the detection of coronary artery disease. Despite its widespread use, the safety of stress echocardiography has not been sufficiently documented in Japanese laboratories. OBJECTIVES: The feasibility, safety, complications and side effects of stress echocardiography were assessed for detecting myocardial ischemia in patients with suspected coronary artery disease. METHODS: 1,866 patients who underwent dobutamine echocardiography(n = 897), exercise echocardiography(n = 722), and dipyridamole echocardiography(n = 247) were prospectively studied from November 1990 to April 2000. Dobutamine was administered intravenously at 5, 10, 20, 30, 40 micrograms/kg/min in 3-minute intervals. Exercise echocardiography used the supine ergometer, starting at 50 W and increasing gradually by 25 W at 3-minute intervals to the maximum of 150 W. Dipyridamole was administered intravenously at 0.14 mg/kg/min for 4 min. After a 4-minute observation period, the drug was re-administered at the same dose for 2 min. RESULTS: The most common side effects under each stress were ventricular premature beats in 34.1% (dobutamine echocardiography), ventricular premature beats in 14.4%(exercise), and headache in 24.3% (dipyridamole). Serious side effects occurred in one patient(0.05%). The case of acute myocardial infarction was caused by dipyridamole echocardiography, and the patient needed emergency coronary angioplasty. Seven patients needed other drug therapy for nonsustained ventricular tachycardia(one), paroxysmal supraventricular tachycardia(two), sinus bradycardia(three), and bronchial asthma(one). There was no incidence of death, shock, or ventricular fibrillation, sustained ventricular tachycardia or other conditions requiring inpatient observation during stress echocardiography. CONCLUSIONS: Stress echocardiography is a reasonable, safe method for determining myocardial ischemia, but may be associated with minor, self-limiting side effects.

Aged↗
PubMed2000

Root system responses of Japanese red cedar saplings to acidic conditions.

Stemflow from Japanese red cedar (Cryptomeria japonica) enters forest soil at a low pH. We evaluated the responses of the root system of Japanese red cedar saplings to acidic conditions, used to simulate this situation, in two different growth media, a brown forest soil (BS) and a Yahagi sand (YS). Soils were acidified by the addition of solutions at pH 2.0, 3.0 and 5.5 (control). Root morphology, root surface area index, root respiration activity and root biomass were measured. In the pH 3.0 treatment, no significant effects were found on the root systems compared with the controls in either soil, except for a slight difference in root-tip diameter in the Yahagi sand. In the pH 2.0 treatment, the surface area index and dry weight ratios of the whole root in the Yahagi sand were significantly lower than those in the other treatments. No significant effects on the whole root were observed in the brown forest soil. These results suggest that detrimental effects of acidic solutions on the root systems would be less significant in brown forest soil, which contains humus, than in the Yahagi sand, which lacks humus. They also suggest that the threshold pH value causing visible morphological changes on the roots of Japanese red cedar saplings falls in the pH range between 2 and 3. White roots in the pH 2.0 treatment had low respiration activity and showed visible morphological changes in both soils. These responses were presumably related to the effects of excess Al in the soil solution. White roots in the pH 2.0 treatment typically produced exodermis. The results suggest that stemflow with a pH of 3.0 has no effects on the root systems of Japanese red cedar, and that the morphology of white roots was adversely affected not by treatment at pH 2.0 but by excess water-soluble Al in the soil.

Journal Article↗
PubMed2000

Cronkhite-Canada syndrome: report of two cases.

Two cases of Cronkhite-Canada syndrome are reported. In the first case, a 56-year-old woman had an adenoma of the colon, arising within the Cronkhite-Canada polyps, which was removed by endoscopic polypectomy. This suggests possible neoplastic transformation of polyps in this syndrome. She achieved remission with corticosteroids, but the polyposis recurred (only in the stomach) 7 months after the remission. In the recurrent polyposis, corticosteroid therapy resulted again in complete remission, which has lasted for 5 years. In the second case, a 69-year-old man developed typical manifestations of the syndrome while under emotional stress. He had a past history of chronic pityriasis lichenoides, and serum antinuclear antibody was positive. These findings suggested a possible role of autoimmune response in the pathogenesis of the syndrome. Corticosteroids were also effective in this patient.

Adenoma↗
PubMed2000

Emulsifying ability of porphyran prepared from dried nori, Porphyra yezoensis, a red alga.

A suspension of low-quality dried nori processed from Porphyra yezoensis, a red alga, was autoclaved at 120 degrees C for 30 min, and from the supernatant, five preparations of porphyran of differing molecular masses and chemical compositions were obtained by preprecipitation with ethanol at stepwise-increasing concentrations of 50 and 67% followed by size-exclusion chromatography. The porphyran preparations exhibited a high emulsifying activity index and high emulsion stability over a wide range of pH and temperature and also in the presence of sodium chloride. An adequately high coefficient of correlation between the median diameter of oil droplets and their 3,6-anhydrogalactose content suggests that 3,6-anhydrogalactose could take part in emulsification with porphyran.

Excipients↗
PubMed2000

Different role of IL-4 in the onset of hapten-induced contact hypersensitivity in BALB/c and C57BL/6 mice.

1. To study the role of interleukin (IL)-4 in the onset of contact hypersensitivity (CH) in mice, the effect of IL-4 gene-depletion and anti-IL-4 monoclonal antibody treatment on dinitrofluorobenzene (DNFB)-induced CH was examined. Simultaneously, to clarify the effect of background gene, DNFB-induced CH in BALB/c and C57BL/6 mice was compared. 2. Five repeated topical applications of DNFB to the ears of mice resulted in CH of the ears in terms of increases in ear thickness and histopathological changes. The magnitude of ear thickness increase in BALB/c mice was almost three times greater than that in C57BL/6 mice. 3. The CH in BALB/c mice was significantly suppressed by IL-4 gene-depletion and anti-IL-4 monoclonal antibody treatment. In contrast, the symptoms of dermatitis in C57BL/6 mice were slightly affected by the same treatment. These changes corresponded well to the production of specific IgE antibody. 4. Total IgE antibody production and the expression of productive Cepsilon mRNA were dramatically suppressed by IL-4 gene-depletion and anti-IL-4 treatment in BALB/c and C57BL/6 mice. Neither total IgG nor IgM levels in either strain of mice was altered by depletion of IL-4. 5. The expression of IFN-gamma in the skin lesion was dramatically suppressed by IL-4 gene-depletion in BALB/c mice, but not in C57BL/6 mice. 6. These findings indicate that IL-4 plays an important role in the onset of DNFB-induced CH in BALB/c mice, but not in C57BL/6 mice.

Animals↗
PubMed2000

Measuring system for lip movements using two video trackers.

Movements of soft tissues surrounding the oral cavity, especially lips and cheeks, have a strong influence on mastication and phonetics. They also influence the relationship between a denture and its oral environment. The purpose of this study was to develop a three-dimensional measuring system for soft tissue movement. This system consisted of two video trackers placed stereographically and a computer. In addition, one video tracker was connected for measuring mandibular movements. The accuracy of this system was evaluated using computerized XYZ pulse stage. The resolution of this system was 0.10 x 0.10 x 0.10 mm, when the measurement was carried out in the area of the 24.0 (X) x 20.0 (Y) x 20.0 (Z) mm with a working distance of 500 mm and a frequency of 120 Hz. In the present study, the lip movements of a dentulous subject with mandibular movements during chewing peanuts were analysed using this system. The new system demonstrated its value for analysing soft tissue movement.

Adult↗
PubMed2000

Electroencephalographic olfactometry (EEGO) analysis of odour responses in dogs.

Scientists in many fields have studied olfaction in dogs, but no simple method exists to study this function. The olfactory ability of dogs is used in many fields. However, the owners of the dogs have a frustrating experience because there is not an easy method to measure olfactory function. The purpose of this study was to examine the characteristics of olfactory function of the dog with electroencephalographic olfactometry (EEGO) recording. It was found that slow waves decreased and rapid waves increased in response to odours. From these results, it is suggested that the rapid waves of EEGO activity are important in determining a dog's olfactory ability. The EEGO recording is effective in diagnosing anosmia in the dog and is easier than a behavioural experiment. Additionally, this method may not cause distress to an animal.

Animals↗
PubMed2000

De novo formation of adipose tissue by controlled release of basic fibroblast growth factor.

De novo adipogenesis at the implanted site of a basement membrane extract (Matrigel) was induced through controlled release of basic fibroblast growth factor (bFGF). bFGF was incorporated into biodegradable gelatin microspheres for its controlled release. When the mixture of Matrigel and bFGF-incorporated gelatin microspheres was implanted subcutaneously into the back of mice, a clearly visible fat pad was formed at the implanted site 6 weeks later. Histologic examination revealed that the de novo formation of adipose tissue accompanied with angiogenesis was observed in the implanted Matrigel at bFGF doses of 0.01, 0.1, and 1 microg/site, the lower and higher doses being less effective. The de novo formation induced by the bFGF-incorporated microspheres was significantly higher than that induced by free bFGF of the same dose. The mRNA of a lipogenesis marker protein, glycerophosphate dehydrogenase, was detected in the formed adipose tissues, biochemically indicating de novo adipogenesis. Free bFGF, the bFGF-incorporated gelatin microspheres, or Marigel alone and bFGF-free gelatin microspheres with or without Matrigel did not induce formation of adipose tissue. This de novo adipogenesis by mixture of Matrigel and the bFGF-incorporated gelatin microspheres will provide a new idea for tissue engineering of adipose tissue.

Adipocytes↗