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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 307 records · Page 17Linked to original sources
PubMed1995

Barium and strontium can substitute for calcium in stimulating nitric oxide production in the endothelium of canine coronary arteries.

We investigated whether Ba2+ and Sr2+ can substitute for Ca2+ in stimulating the nitric oxide (NO) production and cause relaxation in vascular smooth muscle. Ba2+ and Sr2+, like Ca2+, relaxed K(+)-depolarized canine coronary arteries in the presence of diltiazem. The Ba(2+)- and Sr(2+)-induced relaxation was endothelium-dependent and was largely inhibited by NG-monomethyl-L-arginine (L-NMMA) and NG-nitro-L-arginine (L-NNA), but not by indomethacin. These cations increased cyclic GMP levels in the coronary artery to a similar extent, and the increment was completely abolished by L-NMMA. The relaxation induced by each cation was attenuated in the presence of a combination of propranolol, phentolamine and atropine, and L-NNA markedly inhibited any remaining relaxation. This indicates that these cations produce endothelium-dependent relaxation through NO production as well as the relaxation mediated by neurotransmitters. The present study suggests that Ba2+ and Sr2+ can substitute for Ca2+ in the activation of the NO synthase pathway in the endothelium of canine coronary arteries.

Animals↗
PubMed1995

Induction of cyclooxygenase type-2 (COX-2) in rat endometrium at the peak of serum estradiol during the estrus cycle.

We investigated the induction of cyclooxygenase (COX) in rat endometrium during the estrus cycle. The estrus cycle was divided into five stages (proestrus, estrus, diestrus-1, diestrus-2, diestrus-3) by cytological observation of vaginal smears. COX-1 was detected in the endometrium during all five stages of the estrus cycle. In contrast, COX-2 in the endometrium was detectable only in three stages (diestrus-3, proestrus, estrus) and showed a peak at diestrus-3, coinciding with the peak in serum estradiol level, suggesting the estradiol-dependent induction of COX-2.

Animals↗
PubMed1995

[Age-related changes and sex differences on the serum chemistry values in Sprague-Dawley rats--I. 6-30 weeks of age].

Age-related changes of 27 items in serum chemistry were investigated in Sprague-Dawley rats of both sexes from 6 to 30 weeks of age. The following 12 items were shown as an increase in those values during growth and maturity, i.e., total protein, albumin (female only), glucose, total cholesterol, triglyceride, phospholipid (female only), beta-lipoprotein, cholinesterase (female only), asparate aminotransferase (female only), creatinine, direct-bilirubin and total-bilirubin. However, the following 4 items decreased with aging, i.e., asparate aminotransferase, alkaline phosphatase, creatine phosphokinase and inorganic phosphorus. No age-related changes were found in the values for calcium, sodium and chloride in both sexes and for alanine aminotransferase, cholinesterase and albumin in males. The sex differences were shown in the following 12 items: higher values in males were alkaline phosphatase, creatinephosphokinase, glucose and inorganic phosphorus, and higher values in females were cholinesterase, albumin, phospholipid, non-esterified fatty acid, urea nitrogen, direct-bilirubin, total-bilirubin and serum iron. No sex-related differences were found in the values for calcium, sodium, chloride and total cholesterol.

Aging↗
PubMed1995

Enterogenous cyst in the fourth ventricle--case report.

A 53-year-old male presented with a rare enterogenous cyst in the fourth ventricle associated with repeated ventriculoperitoneal shunt malfunction. Surgical excision of the cyst resolved the shunt problems. Electron microscopy findings of the surgical sample were microvilli covered with electron-dense coating materials, basement membrane, and several intercellular junctional devices, suggesting the cyst was derived from the endodermal structure. The viscous and gelatinous contents of the cyst might be responsible for the shunt malfunction.

Cerebral Ventricles↗
PubMed1995

Cytoskeletal organization of the vestibular sensory epithelia.

The cytoskeletal organization of the guinea pig vestibular sensory epithelium was investigated by employing the saponin perfusion method and scanning electron microscopy. The skeletal framework of a a cell was found to consist of actin, intermediate filaments and microtubules. The membrane-bound organelles such as nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, etc. were also well documented. This made it possible to investigate the three-dimensional organization of cytoskeletons as well as their complex interaction with various membrane-bound organelles. The intermediate filaments were demonstrated not only in the supporting cells but also in the sensory cells. They are usually seen surrounding the nucleus and extending through the cytoplasm which connects the nuclear membrane to the plasma membrane, cuticular plate, reticular lamina or other cyto-organelles. The intermediate filaments are also closely related to the desmosomes. These findings suggest that the intermediate filaments provide mechanical support to the cell and its nucleus. In the sensory cells, microtubules are found mainly in the supranuclear portion of the cells, running parallel to the main axis of the cell body, which is directly connected to the cuticular plate. These findings suggest that the microtubules provide the cell with mechanical support and may be closely related to the sensory cell transduction system. Inside the supporting cells, the microtubules are closely related to the secretory granules, Golgi apparatus and intermediate filaments, which supports the idea that the microtubules may control the distribution of intermediate filaments, and also play an important role for transport of the secretory granules.

Animals↗
PubMed1995

Changes in calcium distribution in the utricular supporting cells of the guinea pig.

Changes in calcium distribution in cultured utricular supporting cells following streptomycin sulfate (SM) intoxication were investigated by means of an organ culture system using potassium pyroantimonate (PA) precipitation. PA precipitation showed that calcium ions are located in the otoconia and in the secretory granules of the supporting cells. Exposure of the supporting cells to SM increased the number of lysosomes and reduced the secretory granules in the cytoplasm. These lysosomes had many granules containing calcium ion. It is suggested that calcium secretion from the secretory granules was inhibited by SM and that this might lead to reduction of otoconia.

Animals↗
PubMed1995

Otoconia on the vestibular dark cells of the ampullar areas.

Morphological and metabolic differences in the otoconia on vestibular dark cells of the ampullar area before and after streptomycin treatment were studied by scanning electron microscopy and X-ray microanalyser. Young adult pigmented guinea pigs were used in this study. In the control group, distribution of the otoconia showed a regular pattern. In the SM group the otoconia decreased in numbers and the regularity of the distribution pattern seemed to disappear. Calcium content of the otoconia in SM group also decreased. From these findings, it was concluded that SM might affect not only the sensory and supporting cells but also the vestibular dark cells.

Animals↗
PubMed1995

Effect of streptomycin on the supporting cells of the utricular macula.

Morphological changes in utricular supporting cells in the guinea pig following streptomycin sulfate (SM) intoxication were investigated ultrastructurally in vitro, using an organ culture system. The intracellular structures of the supporting cells, such as the nucleus, mitochondria, and Golgi apparati were well preserved after 7 days in culture. After 10 and 14 days in culture, the supporting cells degenerated. The organ culture system was applied to ototoxicity studies on the supporting cells in utricular macula within 7 days after explanation. When the utricles were exposed to 3, 10 and 30 mg/ml of SM for 3 days, the number of granules in the supporting cells decreased markedly and the number of lysosomes increased daily. The lysosomes contained mitochondria, myeloid bodies, granules and vesicles. Acid phosphatase (AcPase) activity decreased in Golgi apparati and lysosomes. When the concentration of SM was reduced to 3 and 10 mg/ml, the damage to the supporting cells was less marked than that in cells exposed to 30 mg/ml. The supporting cells showed a dose-dependent response with respect to morphological damage. After 3 days culture with 30 mg/ml of SM, the specimens were subsequently cultured for 4 days in a medium without SM. After removal of SM from the medium, lysosomes decreased in number, and the granules and the endoplasmic reticulum showed a gradual increase. The AcPase activity was determined in both lysosomes and Golgi apparatus. This study revealed that the morphological changes in the supporting cells can be reversible.

Acid Phosphatase↗
PubMed1995

Anatomical and physiological characteristics of the vestibular ganglion of the bull frog.

The spatial distribution of nerve fibers from individual vestibular end organs in the vestibular ganglia (VG) was studied using horseradish peroxidase (HRP). HRP was injected into the cut end of the bull frog ampullary nerve. Stained neural elements were counted on the serial sections. Spatial distribution was also studied by recording ampullary nerve compound action potentials (AP) from VG. The anterior semicircular canal (SC) nerves were distributed in the anterior half of VG. The horizontal SC nerves were also distributed in the anterior half of VG, but tended to be posterior. The posterior SC nerves were found predominantly in the posterior half and antero-dorsal portions. These distribution patterns corresponded well with those confirmed by AP recording. There were a few neural connections between anterior and posterior SC, or horizontal and posterior SC, indicating receptor-receptor fibers.

Action Potentials↗
PubMed1995

[A surgical case report of isolated congenital tricuspid valve insufficiency].

A 17-year-old boy observed as a case with Ebstein's anomaly. Echocardiogram and ventriculogram revealed enlargement of the tricuspid valve ring, dysplasia of anterior and posterior leaflet of tricuspid valve, but the anatomy of the septal leaflet was almost normal. According to these findings, the diagnosis of this patient was isolated congenital tricuspid regurgitation. Tricuspid annuloplasty of DeVaga's method and Reed's method were done. Post-operative residual regurgitation was mild. These procedures were resulting in a successful course. Isolated congenital tricuspid valve insufficiency was extremely rare. Only 7 cases of isolated congenital tricuspid insufficiency successfully operated in Japan were collected.

Adolescent↗
PubMed1995

[Anomalous origin of the right pulmonary artery from the ascending aorta: a case report].

We report a successful case of anomalous origin of the right pulmonary artery from the ascending aorta. A 34 days old infant, who had suffered from cardiogenic shock, underwent a direct anastomosis of the right pulmonary artery to the main pulmonary artery behind the ascending aorta under cardiopulmonary bypass. Postoperative catheterization showed no significant stenosis over the anastomosis and normalized pulmonary artery pressure. We conclude that early surgical correction is necessary in the treatment of this life threatening disease.

Anastomosis, Surgical↗
PubMed1995

[Epidural injection for postoperative pain relief after thoracoscopic surgery].

For the pain relief after thoracoscopic surgery, the epidural injection of buprenorphine was performed in 46 cases. In 28 cases, intermittent injection was performed before awaking from anesthesia. The effect was excellent in 6 cases, who were free from pain without any more injection after returning to the ward, and good in 27 cases, who sometimes felt dull pain and had another analgetics (intermittent epidural injection in 16 cases, intermittent epidural injection and another medication in 5 cases). In 18 cases, continuous injection was performed. The effect was excellent in 9 cases and good in 9 cases. It was concluded that the epidural injection had effective analgesic effect after thoracoscopic surgery, both in intermittent injection group and continuous injection group. For limited medication, the intermittent epidural injection was considered the first choice after thoracoscopic surgery.

Analgesia, Epidural↗
PubMed1995

[Interaction between opiate subtypes and serotonin in suppressing noxiously evoked activity of WDR neurons].

The present study examined interactions between mu and delta opiate subtypes and serotonin. Noxious activity evoked by radiant heat (51 degrees C, 8 sec) was extracellularly recorded from single discriminated wide dynamic range (WDR) neurons in decerebrate spinally transected cats. DAGO (mu selective opioid agonist) 1 microgram or DPDPE (delta selective opioid agonist) 30 micrograms was combined with serotonin (n = 6 each) 250 micrograms. The dose of each drug by itself when administered intrathecally produced no suppression of noxiously evoked activity. Although the combination of DAGO and serotonin produced no significant suppression of noxiously evoked activity, DPDPE and serotonin produced significant suppression to 72.8 +/- 8.0 % (mean +/- SEM) of control values (P < 0.01). Intravenously administered naloxone 0.1 mg reversed the suppression produced by the DPDPE-serotonin combination. Our results suggest that combinations of serotonin and delta selective opiates may be more effective in suppressing noxiously evoked activity than combinations with mu selective opiates.

Animals↗
PubMed1995

[Initial ultrafiltration to the priming solution with preserved blood for cardiopulmonary bypass in infants].

In case of open heart surgery in infants, the initial priming solutions (IPS) of the cardiopulmonary bypasses (CPB) include considerable amount of preserved blood to assure us of the proper hematocrit during the CPB. Aiming at elimination of unfavorable effects of preserved blood on hearts and vessels, the ultrafiltrations (UF) to the IPS before the beginnings of CPB had been carried out in 42 pediatric cases. The IPS amounted to 915 +/- 25 (mean +/- SE) ml. in which 581 +/- 31 ml of preserved blood were included. The 1.5-fold amount infusions over the IPS, consisted of 5% glucose, normal saline and fresh frozen plasma, were added to the IPS, and just the same amount fluid were removed out by the UF. The concentrations of potassium, NH3, lactic acid and pyruvic acid in the IPS decreased significantly after UF (p = 0.001). The potassium concentrations were compared among the blood of patients (PB), the IPS before UF (IPS1), the IPS after UF (IPS2), and the mixed blood drawn 5-10 minutes after the beginnings of CPB (MB) in the cases under the age of 1 year (group-I, n = 26, 4.7 +/- 0.3 kg) and in the elders (group-E, n = 16, 15 +/- 2 kg). The results showed all significant differences but "IPS2 and MB" in group-I, and but "PB and MB" in group-E (ANOVA p = 0.001, p < 0.01 by Newman-Keuls). The 98% of cases kept their innate heart beatings until the aortic clamps at 22 +/- 1 degrees C (sending blood temp.).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Transfusion, Autologous↗
PubMed1995

[Pharmacokinetic and clinical studies on SY5555 dry syrup in children].

SY5555 is a new oral penem antibiotic. Pharmacokinetic and clinical studies using SY5555 dry syrup (powder which is dissolved before use) were performed in pediatric patients. 1. Pharmacokinetic investigation Peak plasma concentrations of SY5555 after dose of 5 mg/kg, 10 mg/kg and 15 mg/kg were, respectively, 1.58 +/- 0.37 micrograms/ml, 2.78 +/- 0.54 micrograms/ml and 5.28 micrograms/ml at 1 hour. The average half-life with 5 mg/kg administration was 0.94 +/- 0.05 hours, that with 10 mg/kg was 1.46 +/- 0.31 hours and that with 15 mg/kg was 0.88 hours. 2. Clinical investigation Enrolled in the study were 15 patients including 5 with acute otitis media, 5 with urinary tract infections and 1 each with pharyngitis, tonsillitis, bronchitis, pneumonia and subcutaneous abscess. Responses were excellent in 4 patients, good in 8 patients, fair in 2 patients and poor in 1 patient. In the assessment of the bacteriological efficacy, 8 out of 10 strains of organism identified previous to treatment were eradicated and 2 strains were unchanged, hence the eradication rate was 80.0%. 3. No adverse reactions attributable to the drug were observed and good drug compliance were obtained. From the above results, it has been concluded that SY5555 is a highly effective and safe agent for mild to moderate respiratory and urinary tract infections in children.

Administration, Oral↗