Biomedical subjects
S Imai
Publications and source records attributed to S Imai.
[A family of von Recklinghausen's disease associated with bilateral acoustic neurinomas and falx meningiomas].
A familial or inherited occurrence of von Recklinghausen's disease has been reported hitherto, some of which were associated with intracranial tumors such as gliomas, neurinomas, meningiomas or others. Authers report a family (case 1: father, case 2: son, case 3: daughter) of von Recklinghausen's disease associated with both bilateral acoustic neurinomas and falx meningioma. Case 1. A 41 year-old male was admitted to our hospital with complaints of bilateral hearing disturbance, headache and loss of visual acuity. On admission, neurological examination revealed left papilledema, right cataracta, impairment of bilateral cranial nerves V, IX, X, bilateral deafness, cerebellar ataxia, motor weakness of lower extremities and sensory disturbance of peripheral region of extremities. Twelve subcutaneous nodules were noted over the entire body and Café-au-lait spots were found slightly to be scattered over the chest and the back. Craniogram and vertebral angiography demonstrated bilateral CP angle tumors, and the diagnosis of bilateral acoustic neurinomas was made. Subtotal removal of bilateral tumors and Torkildsen's shunting were carried out. Histological diagnosis was neurinoma. Post-operative course was good. But 6 years later, he complained of gait disturbance. Computed tomography revealed falx meningioma in the frontal lobe and recurrence of bilateral acoustic neurinomas. So meningioma was totally removed. Eight months after surgery he died of aspiration pneumonia aged 47. Case 2. A 15 year-old male, son of case 1, was admitted with complaints of bilateral deafness, gait disturbance and visual disturbance. Neurological examination disclosed left papilledema, right congenital cataracta, impairment of bilateral cranial nerves V, IX, X, ataxic gait and sensory disturbance of right lower extremity.(ABSTRACT TRUNCATED AT 250 WORDS)
[Responses of the posture control system to lateral acceleration disturbances].
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Effects of procaine on the isolated dog coronary artery.
In order to search into the mechanism of the potassium contracture of the dog coronary artery the effects of procaine were studied in the isolated smooth muscle preparation of the dog coronary artery. Procaine is a substance which is known to specifically inhibit the calcium-induced calcium release mechanism. A dose-related relaxation of the potassium contracture was observed with procaine. However, the increase in La3+-resistant 45Ca uptake as measured by the Karaki and Weiss' method (1979) was not inhibited. As reported in a previous paper, caffeine induced a phasic contraction of the fully-depolarized preparation in a calcium-free EGTA containing medium. Procaine produced a dose-related inhibition of this contraction. These findings suggest that the potassium contracture of the dog coronary artery is dependent on the calcium-induced calcium release mechanism. Since the potassium contracture of this preparation can be relaxed by calcium antagonists, it may be inferred that the calcium influx through the voltage-dependent channels may represent the initiation mechanism of the calcium-induced calcium release process.
[A case report of mastopathy with cartilagenous and osseous metaplasia].
A case of mastopathy with cartilagenous and osseous metaplasia is reported. The patient is a 57-year-old Japanese woman complaining of a tumor measuring around 1.2 cm in diameter near the nipple of the left breast. The xeromammographic diagnosis was adenosis with calcification. Histological examination identified an intracystic tumor composed of papilloma and adenosis with cartilagenous and osseous metaplasia. This is the first Japanese case of its kind.
Studies on the biosynthesis of bialaphos (SF-1293) Part 3. Production of phosphinic acid derivatives, MP-103, MP-104 and MP-105, by a blocked mutant of Streptomyces hygroscopicus SF-1293 and their roles in the biosynthesis of bialaphos.
During biosynthetic studies on bialaphos to reveal the formation mechanisms of carbon-phosphorous bonds in detail, three new metabolites containing a H-P-C bond structure were isolated from the fermentation broth of a mutant of Streptomyces hygroscopicus SF-1293. Based on the spectroscopic analysis, the structures of these compounds have been determined as shown in Fig. 1. Transformation experiments of these metabolites to bialaphos suggested that the reduction of the phosphorous atom in phosphate will take place at an early biosynthetic stage.
Tissue and organ distribution of mammary tumor virus antigens in low and high mammary cancer strain mice.
Expression of mammary tumor virus (MTV) antigen was measured in a wide variety of organs and tissues of a series of high (GR, SHN, SHNf, DD, SLN, SLNf) and low (DDf, DDD, DDDf, KF, KFf, ddY, C57BL, BALB/c) mammary cancer strain mice. Tests were carried out by microimmunodiffusion (micro-ID) and immunoperoxidase tests on formalin-fixed tissues and radioimmunoassays in extracts for 2 viral proteins, MTVp27 from the viral core and MTVgp52 from the viral envelope. Organs with exocrine function, i.e. the mammary gland, salivary gland, coagulating gland and prostate, were mostly positive. The secretory epithelial cells of these organs showed viral antigen expression. Less positivity was encountered in brain, pancreas, stomach, urinary bladder, epididymis, uterus, thymus, spleen, lymph nodes and kidney, plasma and blood cell pools. Unexpectedly the uterus extracts showed MTV antigen expression, occasionally even by immunodiffusion, especially in mice of various DD stocks, but also in the GR strain. Another striking observation was the detection of MTV antigen expression in salivary glands in C57BL strain mice; most other organs of this strain (including the mammary glands) were negative. The implications of results of this extensive survey for MTV antigen expression are discussed for tumorigenesis by MTV of mammary gland and perhaps other tissues in the mouse.
The effects of dipyridamole on TXA2 formation by horse platelet microsomes.
The effects of dipyridamole on thromboxane A2 formation by horse platelet microsomes were studied in comparison with those of imidazole, a prototype inhibitor of TXA2 synthetase and nifedipine, a calcium antagonistic vasodilator. Thromboxane A2 was synthesized by incubating PGH2 with horse platelet microsomes and was assayed on the superfused rabbit aorta. Dipyridamole induced as strong an inhibition of TXA2 synthesis as imidazole, while nifedipine was without effects. The possible beneficial clinical outcomes of this effect of dipyridamole are discussed.
Effects of drugs on the cerebral circulation of the dog in relation to the cerebral oxygen consumption.
Drug effects were studied on the cerebral circulation by measuring the sagittal sinus outflow in the anaesthetized dog following the method of Michenfelder and by monitoring cerebral oxygen consumption. Systemic aortic pressure, heart rate and spinal fluid pressure were also studied. Since dilatation of cerebral vessels was observed in nearly all the preparations after inhalation of CO2, it was thought that gross extracerebral contamination was virtually eliminated in this preparation. A close correlation was observed between the oxygen consumption of the brain as a whole and the sagittal sinus outflow (r = 0.93, P less than 0.001); therefore it became feasible to differentiate the direct effects of drugs on cerebral blood vessels from indirect ones attributable to changes in the cerebral oxidative metabolism. Sodium pentobarbitone (5 mg kg-1, i.v.), reduced the cerebral venous outflow and caused a decrease in the oxygen consumption. Pentylenetetrazol (30 mg kg-1 i.v.) and bemegride (5 mg kg-1 i.v.) produced an increase in the blood flow and a corresponding increase in the cerebral oxygen consumption. Thus, it was concluded these substances had no direct effects on the cerebral blood vessels. Acetazolamide (10 mg kg-1, i.v.), a carbonic anhydrase inhibitor, produced a marked and sustained vasodilatation after a latent period of 0.5-1 min. There was no increase in the cerebral oxygen consumption. A similar pattern was seen after CO2 had been inhaled. Methylergometrine and dihydroergotamine (20 micrograms kg-1 i.v.) induced a prolonged vasoconstriction of the cerebral vascular bed without any changes in the oxygen consumption of the brain. Therefore this method can discriminate between indirect or direct effects of drugs on cerebral vascular outflow.
Chemical characterization of extracellular polysaccharides produced by Actinomyces viscosus T14V and T14Av.
The human isolates Actinomyces viscosus T14V and T14Av produced extracellular polysaccharides in the absence of sucrose. In contrast to strain T14V, strain T14Av produced abundant viscous slime polysaccharide in the culture supernatant fluids when grown in a chemically defined medium containing glucose. After resolution of the T14Av polysaccharides into seven fractions, it was demonstrated that two of these exhibited viscous properties and lacked methylpentose and muramic acid. The major slime polysaccharide purified by gel filtration and ion-exchange column chromatography contained 39% (moles percent carbohydrate) galactose, 37% N-acetylglucosamine, 19% glucose, and 5% mannose. Only trace amounts of protein and phosphorus were detected in this preparation. On the other hand, strain T14V produced negligible slime polysaccharide under the same culture conditions. The major extracellular polysaccharide fraction from this strain contained methylpentoses, hexoses, hexosamines, muramic acid, protein, and phosphorus, suggesting that this fraction might be derived from the cell wall.
Arterial pressure-urinary output relationship in DOCA-saline hypertensive rats.
To know the role played by the kidney in the genesis of deoxycorticosterone acetate (DOCA)-saline hypertension, the arterial pressure-urinary output (AP-UO) relationship was compared in unanesthetized, unrestrained uninephrectomized (1-K) control and normal Wistar-Imamichi (W-I) rats according to the method of Norman et al. [Am. J. Physiol. 234 (Regulatory Integrative Comp. Physiol. 3): R98-R103, 1973]. The gradient of AP-UO relationship was slightly decreased in 1-K control rats compared with that in W-I rats. However, the AP-UO relationship of DOCA-saline hypertensive rats underwent only a parallel shift to higher blood pressure ranges compared with that of 1-K control rats. There was no significant change in the urinary volume, urinary sodium excretion, and urinary osmolarity. Furthermore, the AP-UO relationship was shifted back to the lower pressure range under the influence of hydralazine, a preferential renal arteriolar dilator, suggesting that constriction of the renal artery caused the rise of the arterial pressure in DOCA-saline hypertensive rats.
Eccrine nevus with epidermal changes.
A 22-year-old woman with papular lesions on the extensor aspect of the left leg, present since childhood, with linear distribution is described. Histology of the lesion showed malformed eccrine sweat apparatus with ductal hyperplasia, in addition to the serrated configuration of the epidermis. It appears that the lesions of the eccrine apparatus in this case represent a nevus.
Quantitative analysis of the antiarrhythmic effect of drugs on canine ventricular arrhythmias by the determination of minimum effective plasma concentrations.
Antiarrhythmic effects and minimum antiarrhythmic plasma concentrations (min PC) were examined using three canine ventricular arrhythmia models, i.e., two-stage coronary ligation arrhythmia (Cor), halothane-adrenaline arrhythmia (Adr) and digitalis arrhythmia (Dig). Disopyramide suppressed these three arrhythmias and its min PCs were 5.3 +/- 1.8 (Cor), 4.2 +/- 1.1 (Adr) and 1.7 +/- 0.4 micrograms/ml (Dig). Procainamide suppressed coronary ligation arrhythmia and its min PC was 27.1 +/- 4.0 micrograms/ml, but was not effective on adrenaline arrhythmia. Aprindine was effective on three arrhythmias and its min PCs were 1.6 +/- 0.3 (Cor), 1.0 +/- 0.4 (Adr) and 0.8 +/- 0.4 micrograms/ml (Dig). Lidocaine was not effective on coronary ligation arrhythmia, but was effective on adrenaline arrhythmia and its min PC was 15 micrograms/ml. Phenytoin was effective on three arrhythmias and its min PCs were 9.8 +/- 2.0 (Cor), 12.1 +/- 3.1 (Adr) and 11.3 +/- 3.0 micrograms/ml (Dig). It was not specifically effective on canine digitalis arrhythmia. Propranolol and other beta-blockers were effective on adrenaline arrhythmia, but very high doses were necessary for suppressing coronary ligation and digitalis arrhythmias. Verapamil was only effective on adrenaline arrhythmia and its min PC was 0.03 +/- 0.01 microgram/ml. Canine min PCs of drugs were almost the same as those reported in man except for procainamide and lidocaine. Membrane stabilizing effects seem to be important for suppressing canine ventricular arrhythmias.
Effects of prostaglandins on late coronary ligation arrhythmias in the dog.
Effects of an intravenous injection of indomethacin, prostaglandins (PGs) E1, E2 and F2 alpha and prostacyclin were examined by the use of a model of two-stage coronary ligation arrhythmias in conscious dogs. Indomethacin had no effect on the arrhythmias occurring 48 hr after coronary ligation. PGs and prostacyclin were injected after the injection of indomethacin. PGs did not show any significant antiarrhythmic effects on the arrhythmias occurring 48 hr after coronary ligation, while prostacyclin showed a transient arrhythmogenic effect. From the foregoing results, both endogenous and exogenous PGs do not seem to play a significant role in the genesis of late coronary ligation arrhythmias in the dog.
Binding characteristics of 3H-dihydroalprenolol to beta-adrenoceptors of rat heart treated with neuraminidase.
Binding characteristics of the beta-blockers and beta-agonists with the beta-adrenoceptors were investigated in 3H-dihydroalprenolol (3H-DHA) binding to rat heart membranes treated with neuraminidase. When 60% of the total sialic acid content in the membranes was removed, reproducibility of the binding assay became much better than was attainable without neuraminidase treatment, and the maximum density of beta-adrenoceptors was increased. These data suggest that the binding of the test compounds with the beta-adrenergic receptors in cardiac muscle was under the influence of the sialic acid of the glycocalyx of the membrane. The 3H-DHA binding sites in membranes treated with neuraminidase showed a strict stereo-specificity when tested with propranolol. The ranking order of inhibition of beta-antagonists or agonists is: dl-propranolol greater than oxprenolol greater than alprenolol greater than pindolol greater than YM-09538 greater than labetalol greater than acebutolol greater than atenolol greater than metoprolol greater than sotalol greater than butoxamine greater than practolol as antagonists or l-isoproterenol greater than l-epinephrine greater than l-norepinephrine as agonists. A good correlation (r = 0.91, P less than 0.001) was observed between the Ki values observed by the present binding assay and the pA2 observed in the guinea-pig atria relative to the positive inotropic effect by Bieth et al. (Br. J. Pharmacol. 68, 563-569, 1980), indicating that the present method will be useful for screening new beta-adrenergic receptor antagonists or agonists.
A new method for the serial cultivation of Tritrichomonas muris.
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Composition of intestinal ciliates and bacteria excreted in feces of the race-horse.
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A new ciliate, Spirodinium magnum sp. nov., from the light horse.
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