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Biomedical subjects

K Miyake

Publications and source records attributed to K Miyake.

At least 523 records · Page 29Linked to original sources
PubMed1989

Functional changes of aorta with massive accumulation of calcium.

The present study was undertaken to elucidate pathophysiological changes and functional alterations of the calcified artery. For this purpose, rats were treated with 500,000 units/kg vitamin D3, and tension development of isolated rat aortae was examined. Treatment of rats with vitamin D3 resulted in an increase (approx. 64-fold) in the tissue calcium. Light microscopic examination of the aorta after staining with hematoxylin-eosin and von Kossa indicated numerous plaques in the aortic media. The results indicate a massive accumulation of calcium in the aortic media. Responsiveness of the calcified tissue to norepinephrine, epinephrine, serotonin, prostaglandin F2 alpha was found to be 11-66% when compared to that of the control. Furthermore, the calcified tissue responded minimally to isoproterenol and acetylcholine, which elicited a relaxation in control aortae. Isoproterenol-induced relaxation of the calcified aorta after 100 mM KCl contracture was also diminished. In the present study we have demonstrated poor responsiveness of the calcified aorta to physiological and pharmacological substances relative to normal tissue, which implies a functional damage of the artery upon massive calcium accumulation.

Acetylcholine↗
PubMed1989

Pupillary fibrin membrane. A frequent early complication after posterior chamber lens implantation in Japan.

The incidence of pupillary fibrin membrane formation, a relatively frequent complication of cataract surgery in Japan even for experienced surgeons, was noted in 2038 consecutive cases of senile cataract removal and primary posterior chamber intraocular lens (PC IOL) implantation. The overall incidence was 4.4%. Comparisons among cases showed the incidence to be significantly higher among: (1) patients who received dry- versus wet-sterilized lenses (P less than 0.001), (2) eyes with premature, subcapsular, or nuclear cataracts than among those with mature cataracts (P less than 0.05), (3) patients with systemic hypertension (P less than 0.01), (4) eyes not treated postsurgically with topical antiprostaglandins (P less than 0.001), and (5) patients who had undergone previous PC IOL implantation in the fellow eye (P less than 0.001). These findings suggest that the formation of the fibrin membrane is a kind of immunologic reaction. Accordingly, use of antiprostaglandin agents and complete removal of lens material and epithelial cells are recommended, especially for patients undergoing second-eye operations or those with a predisposition to breakdown of the blood-aqueous barrier.

Aged↗
PubMed1989

Beneficial effect of amosulalol and phentolamine on post-hypoxic recovery of contractile force and energy metabolism in rabbit hearts.

1. The effects of phentolamine, an alpha-adrenoceptor blocking agent and amousulalol, an alpha 1 and beta-adrenoceptor antagonist on hypoxia-induced impairment in cardiac function and metabolism were examined using the isolated heart Langendorff preparation of the rabbit. 2. Hypoxia induced cessation of cardiac contractile force, a rise in resting tension, a decrease in myocardial high-energy phosphates, an increase in tissue calcium content and the release of ATP metabolites from the heart. Subsequent reoxygenation resulted in little recovery of cardiac contractile force, and there were further increases in tissue calcium content and in the release of creatine kinase from the heart. 3. Treatment of hypoxic hearts with either 83 microM phentolamine or 45 microM amosulalol resulted in a suppression of the rise in resting tension, the tissue calcium accumulation and the release of creatine kinase and ATP metabolites during hypoxia. This treatment also elicited significant recovery of cardiac contractile force, restoration of myocardial high-energy phosphates, suppression of the release of creatine kinase and the accumulation of tissue calcium during reoxygenation. Both 83 microM phentolamine and 45 microM amosulalol a significant prolongation of the effective refractory period of rabbit isolated atria. 4. Lower concentrations of phentolamine (16 microM) and amosulalol) (9 microM), which are sufficient to exert an alpha-adrenoceptor blocking action, did not elicit an appreciable effect on the post-hypoxic recovery of cardiac contractile force. 5. These results suggest that phentolamine and amosulalol are capable of protecting the myocardium from hypoxia-induced derangements in cardiac function and metabolism. This effect is probably attributable to their membrane stabilizing effect, rather than to their alpha-adrenoceptor blocking action.

Adenosine Triphosphate↗
PubMed1989

Possible therapeutic effect of naftidrofuryl oxalate on brain energy metabolism after microsphere-induced cerebral embolism.

1. The present study was designed to determine whether naftidrofuryl oxalate exerts a possible therapeutic effect on brain energy metabolism impaired by microsphere-induced cerebral embolism in vitro. 2. Injection of microspheres into the right carotid canal resulted in a decrease in tissue high-energy phosphates both in the right and left hemispheres, and an increase in tissue lactate in the right hemisphere, on the 3rd and the 5th day after the embolism. The embolism also induced a marked reduction in mitochondrial oxidative phosphorylation ability and succinate dehydrogenase activity. The results suggest that severe ischaemia was induced in the brain by the microsphere administration. 3. Treatment of microsphere-injected rats with naftidrofuryl oxalate (15 mg kg-1) for 3 or 5 days elicited a significant recovery of tissue high-energy phosphate and lactate levels. The recovery was associated with a significant restoration of mitochondrial succinate dehydrogenase activity on the both days and of mitochondrial oxidative phosphorylation rate on the 5th day. 4. The results suggest that naftidrofuryl oxalate is beneficial in the recovery of cerebral energy metabolism impaired by microsphere-induced cerebral ischaemia, presumably through a mechanism involving its direct effect on the cerebral mitochondrial enzyme activities.

Adenosine Triphosphate↗
PubMed1989

Detection and properties of A-factor-binding protein from Streptomyces griseus.

The optically active form of tritium-labeled A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone), a pleiotropic autoregulator responsible for streptomycin production, streptomycin resistance, and sporulation in Streptomyces griseus, was chemically synthesized. By using the radioactive A-factor, a binding protein for A-factor was detected in the cytoplasmic fraction of this organism. The binding protein had an apparent molecular weight of approximately 26,000, as determined by gel filtration. Scatchard analysis suggested that A-factor bound the protein in the molar ratio of 1:1 with a binding constant, Kd, of 0.7 nM. The number of the binding protein was roughly estimated to be 37 per genome. The "inducing material" virginiae butanolide C (VB-C), which has a structure very similar to that of A-factor and is essential for virginiamycin production in Streptomyces virginiae, did not inhibit binding. In addition, no protein capable of specifically binding 3H-labeled VB-C was found in S. griseus. Together with the observation that VB-C had almost no biological activity on the restoration of streptomycin production or sporulation in an A-factor-deficient mutant of S. griseus, these results indicated that the binding protein had a strict ligand specificity. Examination for an A-factor-binding protein in Streptomyces coelicolor A3(2) and Streptomyces lividans showed the absence of any specifically binding protein.

4-Butyrolactone↗
PubMed1989

Multivariate evaluation of determinants affecting regional lymph node metastasis and survival in bladder cancer patients who underwent radical cystectomy.

To elucidate the relative importance of clinicopathologic factors affecting regional lymph node metastasis and survival in bladder cancer patients, multivariate analyses by the logistic regression model and proportional hazards model were performed for 86 patients who underwent radical cystectomy between 1978 and 1988. Clinicopathologic factors included in the analysis were sex, age, prior tumor history, time from onset of symptoms to cystectomy, and tumor characteristics (size, number, growth pattern, grade, stage, infiltration pattern, lymphatic invasion, lymphocytic infiltration around tumors, and lymph node metastasis). Nineteen of eighty-six patients (22%) had regional lymph node metastasis. Univariate analysis showed that lymph node metastasis was related to stage (p = 0.0006), lymphatic invasion (p = 0.006) and infiltration pattern (p = 0.02). Multivariate analysis revealed that stage is the only determinant of statistical significance for lymph node metastasis. High-stage tumors (pT3a-pT4) had 15 times higher risk for lymph node metastasis than low-stage tumors (pTis-pT2). The 5-year survival rates were 25 and 75% for patients with and without lymph node metastasis, respectively. Proportional hazards model revealed that stage is the most significant determinant (p = 0.0001) for survival, followed by lymph node metastasis with borderline significance (0.005 less than p less than 0.1). A two-factor model consisting of stage and lymph node metastasis yielded corrected hazard ratios of 14.7 for stage and 2.3 for lymph node metastasis. The present study quantitatively confirms previous univariate analyses of factors affecting lymph node metastasis and survival in patients undergoing radical cystectomy.

Adult↗
PubMed1989

Ocular pharmacokinetics of latamoxef and cefaclor in humans. Penetration into aqueous humor.

Penetrations of latamoxef (LMOX) and cefaclor (CCL) into the aqueous humor after intravenous or oral administration were investigated in patients admitted with cataract. Concentrations of antibiotics in plasma and aqueous humor were determined periodically by microbiological assay. LMOX disappeared from plasma in a monoexponential manner with a half-life of 2.7 h after intravenous administration at a dose of 1000 mg. The maximum concentration of LMOX in aqueous humor (4.7 micrograms/ml) was observed 2 h after administration. When CCL was administered orally at a dose of 500 mg, the maximum concentration of CCL in aqueous humor was 0.53 microgram/ml 2 h after administration, whereas the maximum plasma concentration of 8.4 micrograms/ml was observed at 1 h. Pharmacokinetic analysis (simultaneous simulation) of plasma and aqueous humor concentration-time courses was done by using the best-fitting compartment model examined (modified two-compartment model). Prediction of the concentration of antibiotics in aqueous humor from the plasma concentration profile was also examined using the same compartment model in a separate experiment. The predicted concentration in aqueous humor was proved to fit reasonably with the measured concentration.

Aged↗
PubMed1989

[The effects of prenatal trimethyltin exposure on development and learning in the rat].

Developmental effects of single prenatal trimethyltin exposure were examined in THA rats. Pregnant rats were injected on gestational day 12 with single dose of trimethyltin chloride (TMT) ip at either 0, 5, or 7 mg/kg. Significant differences between treated and control offspring rats could not be observed in terms of body weight, pinna detachment, incisor eruption, eye opening, surface righting, cliff avoidance, pivoting, negative geotaxis and auditory startle. Spontaneous motor activity and open field behavior in the rats were also not affected by TMT. In Sidman avoidance test, however, the avoidance rate of the treated offspring rats was lower when compared to that of the controls. These results suggest that prenatal TMT administration disrupts learning acquisition.

Animals↗
PubMed1989

Effects of postnatal low-levels of exposure to styrene on behavior and development in rats.

Three groups of rats were exposed by inhalation to either clean air (control group) or styrene monomer at 25 and 50 ppm (styrene-exposed groups) for 7 h/day, 6 day/week, from 1 to 48 days of age. Compared to control group, Styrene-exposed groups showed significant delay in the following developmental indices: body weight gain, appearance of pinna detachment and incisor eruption. With respect to open-field activity, the styrene groups indicated longer latency to enter the field, less number of squares crossed and fewer rearings than those of controls. In the avoidance behavior aspect, the styrene groups attained less achievement level in avoidance rates than that of the control group. Dose-related trends were found between the two exposed groups in body weight increment, exploratory and avoidance behavior. Sex differences were seen on these factors also. These results suggest that at postnatal exposure of low-levels to styrene affects behavior and development in rats.

Animals↗
PubMed1989

Ruptured intracranial aneurysm in a 19-day-old infant--case report.

The authors describe the case of a 19-day-old infant with a ruptured intracranial aneurysm. She had suddenly become lethargic after drinking milk. Cerebral angiography demonstrated a large aneurysm arising from the right middle cerebral artery. Because the aneurysm was fusiform, the parent artery was clipped. Histological examination of a specimen taken from the aneurysmal dome showed an organized thrombus with deposition of a calcium-like substance in the wall, which appeared on histochemical examination to be pseudolime. The postoperative course was uneventful and she was discharged without neurological deficits.

Female↗
PubMed1989

[Clinical study of a modified Stamey's endoscopic bladder neck suspension procedure for one hundred female patients with stress incontinence].

One hundred female patients with stress incontinence have been operated on by means of modified stamey's endoscopic bladder neck suspension procedure, i.e. quantifying the thread tension for bladder neck suspension. Twelve patients had 1,000 grams in the nylon loop, 5,800 grams, 9,700 grams, 25,600 grams and 49,400 grams. A follow-up period varied from 10 to 32 months (mean: 20.5 months). A 60-min pad-weighing test revealed urinary loss of 1.0 to 196.0 grams/hour (mean: 36.0) prior to operation. 1. The modified Stamey's procedure was successful in 95 patients (95%). The appropriate thread tension for bladder neck suspension was 400 grams. 2. Various complications were encountered: removal of unilateral nylon suture was necessitated in 2 patients, bleeding from operative wound in 2, bladder tamponade in 2, and clean intermittent catheterization for more than one month in 4. 3. Micturition parameters, i.e. maximum and average flow rates, temporarily got worse post-operatively. Maximum urethral closure pressure decreased and functional profile length elongated which were significantly different from those of pre-operative values. 4. Questionnaire sent to the patients revealed that 89 percent of them were satisfied with the operative results but 11 percent were not. 5. The modified Stamey's procedure is simple to perform and prevents over-tightness of nylon loops. We conclude that this operative method is the treatment of choice for correction of stress incontinence.

Adult↗
PubMed1989

[Increase in aqueous flare by a therapeutic dose of mannitol in humans].

To evaluate the effects of mannitol on aqueous flare (aqueous protein concentration), we administered an intravenous clinical therapeutic dose to normal young adults (average age, 20.1 years), to normal older adults (average age, 61.3 years), and also to patients with diabetes mellitus, systemic hypertension, or pseudoexfoliation syndrome who were about to undergo intraocular surgery (average age, 66.4 years). Protein and cell levels in the aqueous fluid were determined with a device that measures laser light scattering in the aqueous fluid. Mannitol increased aqueous flare intensity. In all subjects, aqueous flare intensity was greatest around one hour following drug administration; the magnitude and the duration of the aqueous flare increase were significantly greater in normal older subject than in normal young adults; the magnitude was essentially the same in older adults with and without diseased barrier. The effect was reversed within 6 hours of drug administration in normal subjects. We considered the findings to represent changes in actual aqueous protein concentration and discussed the possible causes of this phenomenon.

Adult↗
PubMed1989

Biphasic fluorescence decay in kinetic vitreous fluorophotometry.

Eyes of 15 normal subjects and 24 diabetic patients underwent kinetic vitreous fluorophotometry at five, six, eight, ten, 24, and 48 hours after intravenous administration of sodium fluorescein 10 mg/kg. Exponential decay constants (Kv) were calculated for the period between five and 24 hours (Kv1) and for that between 24 and 48 hours (Kv2). In normal subjects and diabetic patients with background retinopathy, Kv1 was larger than Kv2, indicating biphasic fluorescence decay. However, in patients with proliferative retinopathy, Kv1 was significantly smaller than in other subjects, so Kv1 - Kv2 was smaller than that of the controls.

Diabetic Retinopathy↗
PubMed1989

Critical period of brain development in learning caused by lead exposure in rats.

Three groups of rats (group a, b and c) with high and stable avoidance, and low variability, named Tokai High Avoiders (THA) strain. (a) via placenta from the 13th day of gestation, through maternal milk during lactation and per os after weaning (group Pb-gestation), (b) through maternal milk during lactation and per os after weaning (group Pb-birth), (c) per os after wearing (group Pb-weaning). The pre- and postnatal lead exposure induced apparent delays in speed of learning acquisition and broke the uniformity in avoidance rate in both males and females. Postnatal lead exposure caused slight delays in speed of learning acquisition in males alone. In the post wearing period defect in learning due to lead exposure could be observed in both males and females. No apparent difference was present in the development of pups among the lead exposed groups and control. From these results, it could be deduced that the most sensitive period of brain development in learning affected by lead exposure was the pre- and early postnatal period in the rat.

Age Factors↗
PubMed1989

[Report of two cases of long ureteral polyps and review of literature].

Two cases of long ureteral polyps are presented. The patients were a 46-and a 40-year-old women, complaining of gross hematuria and miction pain respectively. Excretory urographies showed filling defects of right ureter and lower part of left ureter respectively. Right and left total nephroureterectomy with bladder cuff were respectively performed because of malignant possibility. The tumors removed were benign polyps, measuring 19 and 5 cm in length, respectively. The 19 cm polyp is the longest in Japan. The former case was suspected as hamartoma from müllerian duct and the latter as simple fibro-epithelial polyp.

Adult↗
PubMed1989

[A case of esophageal cancer metastatic to the kidney presenting as renal pelvic cancer].

A 50-year-old man, who had undergone operation of esophageal carcinoma 2 years earlier, was admitted with the complaints of right flank pain and macroscopic hematuria. Intravenous urogram showed right unvisualized kidney. Right retrograde pyelography showed the dilatation of calices and irregularity of middle and lower calices. Computed tomography revealed severe hydronephrosis of the right kidney. Right nephrectomy was performed under the diagnosis of either renal pelvic cancer or esophageal cancer metastatic to the kidney. Pathological examination revealed metastatic squamous cell carcinoma from esophagus. The patient was treated by radiotherapy but died 4 months after the surgical treatment. Literature on eight case of metastatic renal cancer from esophagus is reviewed.

Carcinoma, Squamous Cell↗