Brain tumors induced in hamsters by intracerebral inoculation of SR-RSV-infected embryonic brain cells

Brain tumors were induced in Syrian hamsters by intracerebral inoculation of brain cells which were obtained from 12-day old syngeneic hamster and infected with Schmidt-Ruppin strain of Rous sarcoma virus (SR-RSV) in vitro. A total of 212 tumors were developed in all 25 recipients within 19 to 125 days after transplantation. On the basis of light and electron microscopic study, they were classified into four main groups: astrocytoma (45.8%), pleomorphic glioma (50.0%), sarcoma (3.8%), unclassified (0.4%). The morphological features of these tumors were described, and the advantages of this brain tumor model were discussed.

Potentiation by dipyridamole of the inhibition of guinea-pig ileum twitch response caused by adenine derivatives

The inhibition actions of adenosine and adenine nucleotides, such as ATP, AMP and cyclic AMP, on contractions of guinea-pig from ileum induced by transmural stimulation were potentiated by dipyridamole, whereas those of inosine, morphine and tetrodotoxin were not affected. Tritium activity, accumulated during incubation of the ileal segments with [3H]adenosine, was reduced by dipyridamole. The adenosine added was degraded to inosine and then hypoxanthine during incubation, with the ileal segments, thereby restoring the twitch response of the ileal segments. In the presence of dipyridamole, the degradation of adenosine and the recovery of the twitch response was retarded. Thus, dipyridamole may potentiate the inhibitory actions of adenosine and adenine nucleotides on the twitch response of the ileum by inhibiting both the accumulation and the degradation of adenosine.

Effects of cholinesterase inhibitors on the spasmogenic action of acetate esters on rat uterus

Acetate esters, such as phenyl acetate and aspirin, induced atropine-sensitive contractions of isolated uterus only when choline was present. These contractions were selectively and reversibly inhibited by carbamate-type cholinesterase inhibitors, such as neostigmine and eserine, and quaternary ammonium compounds, such as tetraethylammonium and decamethonium. After treatment with organophosphorus cholinesterase inhibitors, such as di-isopropyl fluorophosphate and tetraethyl pyrophosphate, the uterus failed to respond to the acetate esters, even when high concentrations of choline were present. The inhibition of the response of the uterus by organophosphates was effectively removed by pyridine-2-aldoxime methiodide. Pretreatment of the uterus with neostigmine or simultaneous addition of high concentrations of quaternary ammonium compounds prevented the inhibition by organophosphates. The inhibition produced by neostigmine was also reduced by simultaneous addition of quaternary ammonium compounds. These findings suggest that some esterase having an anionic site and an esteratic site, probably cholinesterase, may mediate in the uterine contractions induced by acetate esters in the presence of choline, and that inhibition by organophosphates, carbamates and quaternary ammonium compounds of cholinesterase activity in the preparation may impede the initiation of contractions by the acetate esters in the presence of choline.

Raphe induced inhibition of intralaminar thalamic unitary activities and its blockade by para-chlorophenylalanine in cats

Extracellular recordings were made of intralaminar thalamic neurones responding to stimulation of the radial nerves. The effects on this response of a conditioning stimulation of the median raphe nucleus were studied in both untreated and p-CPA pretreated cats. Ninety-two percent of thalamic responses to somatic stimulation in untreated cats was inhibited by conditioning stimulation of the raphe nucleus. The intensities of conditioning stimulation required for the inhibition were significantly higher in cats pretreated with p-CPA than in cats not treated with the drug. It is suggested that raphe projection to intralaminar thalamus excerts an inhibitory influence on thalamic activities, and that the inhibition is mediated by a putative neurotransmitter, serotonin. The possible involvement of the median raphe nucleus in pain processing is discussed.

Excess loss caused by the outer layer in a multimode step-index optical fiber: theory

An equation has been derived using an electromagnetic theory for evaluating excess loss caused by the outer layer (jacket) coated around the cladding in a multimode step-index fiber. Using the derived equation for the LP modes, numerical calculations have been made by varying parameters such as fiber and jacket parameters, wavelength, and mode power distribution. The calculations have revealed that the excess loss is especially influenced by the refractive index of the jacket, cladding thickness, and mode power distribution in the fiber.

Aspects of the spasmogenic effects of acetate esters on ileal smooth muscle

Acetate esters, such as aspirin methylester, aspirin and resorcinol monoacetate, induced contractions of guinea-pig ileum. Their actions were selectively antagonized by atropine, but were not affected by ganglion blocking agents, conduction blockers, aging with cooling, anoxia or antihistaminics. On the other hand, N-acetates, such as acetanilide and p-acetaminophenol, and no contractile action on the ileum. These acetate esters thus seemed to have a cholinergic action, and not a direct action on muscle or other known specific receptors for endogenous active substances. The contractions induced by the acetate esters were selectively potentiated by low concentrations of choline, whereas those induced by acetylcholine, nicotine, 5-hydroxytryptamine and histamine were not. However, N-acetates did not induce the contractions even in the presence of choline. Organophosphorus cholinesterase inhibitors, such as diisopropyl fluorophosphate and paraoxon, selectively and irreversibly inhibited the actions of aspirin and N,O-diacetyl-p-aminophenol with or without choline. From these results, it is concluded that the acetate esters with or without choline act through the cholinergic system. However, their actions cannot be explained in terms of known mechanisms, such as acetylcholine release, cholinesterase inhibition or a direct muscarinic action. Therefore, the acetate esters, including phenyl acetate which was supposed to be a releaser of acetylcholine, seem to have a hitherto undescribed type of cholinergic action whose mechanism is unknown. It seems that organophosphate-sensitive esterase(s) in the preparation may be essential for initiation of the actions of the acetate esters with or without choline, but the mechanism of the effect of choline is unknown.

Effects of palytoxin on isolated intestinal and vascular smooth muscles

Palytoxin (PTX), the most potent marine toxin isolated from the Zoanthid, Palythoa tuberculosa, was studied to determine the effect on isolated smooth muscles. In guinea pig taenia coli PTX at above 3 X 10(-10) g/ml caused a contraction which slowly subsided under isotonic recording. Under isometric recording PTX at above 1 X 10(-10) g/ml caused a contraction which depended on the spontaneous activity. The PTX-induced contraction was not affected by atropine, tripelenmamine or tetrodotoxin but was inhibited by 5 mM Mg, norephinrphrine, isoprenaline or papaverine. PTX at above 1 X 10(-9) g/ml induced an increase in spike frequency and a slight depolarization accompanied with a contraction when measured using a sucrose gap method. In some cases the spike generation was almost abolished after a long exposure to higher dose of PTX and the developed tension gradually decreased. Under isometric recording PTX caused a sustained contraction in rabbit aorta, dog mesenteric and coronary arteries at above 1 X 10(-10) and 1 X 10(-11) g/ml, respectively, in a dose-dependent manner. The coronary artery was most sensitive among the preparation used. PTX-induced contraction in aorta was irreversible, was not influenced by phentolamine but diminished with 5 mM Mg and disappeared in a D-600 or Ca-free medium. PTX is thus an extremely potent and direct stimulant which acts on smooth muscles.

Selective alpha-adrenoceptor blocking actions of a new derivative of 2-halogenotheylamine: 6-(2-bromoethyl)-10,11-methylenedioxy-5,6,7,8-tetrahydrodibenz[c,e]azocine

A new compound, 6-(2-bromoethyl)-10,11-methylenedioxy-5,6,7,8-tetrahydrodibenz [c,e] azocine (DA-VIII-MBr) was found to have a more selective alpha-adrenergic blocking action than dibenamine or phenoxybenzamine. From dose-response curves for adrenaline and 5-hydroxytryptamine (5-HT) obtained in strips of rat aorta before and after incubation with each of the three blocking agents, the fractions of receptors remaining active for adrenaline and 5-HT, respectively, were estimated. After blockade with DA-VIII-MBr the receptors for adrenaline were blocked considerably, but those for 5-HT were little affected. Dibenamine blocked the receptors to adrenaline and 5-HT almost equally. The effective dose of phenoxybenzamine for adrenaline receptors was less than one hundredth that of dibenamine or DA-VIII-MBr, but specificity for these receptors was intermediate between those of dibenamine and DA-VIII-MBr. The structure of DA-VIII-MBr is an analog of apogalanthamine and its nitrogen atom bears the 2-halogenoethylamine group in part of an eight membered ring.

Effect of anoxia on isotonic shortening induced by high-K medium in rat uterus

The effect of anoxia on the shortening induced by high-K medium was investigated in isolated rat uterus. The shortening induced by high-K medium was maintained for 75 min or more under normoxia in the initial load (0.35 g). Under normoxia 1, 2, 2.5, and 3 g load to the uterus reduced the maximum shortening induced by high-K medium to 93, 65, 18 and 3%, respectively. Under anoxia the high-K-induced shortening in the initial load was not so affected and it was maintained at least for 60 min. However, against 0.7 and 1 g load to the uterus, the maximum shortening reduced greatly to 14 and 13% under anoxia. Effects of anoxia on the shortenings induced by high-K medium in guinea pigs taenia coli and longitudinal muscle from ileum were also studied. Our observations support the theory that the shortening of the light loaded muscle under anoxia is maintained by only a little force and the muscle may not be so dependent on metabolic energy.

The mobile clinic of St. Mary's health center--a functional plan

Specialized medical facilities tend to be concentrated in medical centers in metropolitan areas, which results in unavailability of adequate medical care to large portions of our population. One solution is a mobile unit, staffed by personnel representing several different disciplines (physicians, nurses, social workers, nutritionists, etc) and extending a health ministry beyond the confines of a medical center to medically deprived areas. The unit also has educational benefits as the medical and nursing students gain valuable experience by evaluating the patients and relating them to the environment in which they live. The mobile clinic allows for a workable situation in a congenial atmosphere without compromising the quality of health care.

Temperature-pH effect upon germination of bacterial spores

Using several kinds of criteria for the germination of bacterial spores, germination-pH curves were drawn for Bacillus subtilis spores observed at different temperatures. The experiments revealed that optimum pH for spore germination was markedly changed by changing the incubation temperature; the optimum pH for germination was 7.4 at 37 degrees C and 5.4 at 10 degrees C. A possible mechanism involved in this phenomenon is discussed.

Difference between inhibitory actions of papaverine and dehydroepiandrosterone on the isolated guinea-pig ileum

Dehydroepiandrosterone (DEA), a metabolite of steroid hormone in the urine, differed from papaverine in the mode of inhibitory action on the isolated guinea-pig ileum. Papaverine inhibited both phasic and tonic contractions induced by an agonist, while DEA inhibited the phasic contraction without apparent fatigue of the tonic phase. The main action of papaverine seems to be predominatly a metabolic inhibition similar to that of metabolic inhibitors, but the action of DEA could not be ascribed to that of metabolic inhibition. In the presence of papaverine or metabolic inhibitors the height of maximal contraction of an agonist tested by the cumulative method was greatly depressed and less than that by a single method. The longer the time involved in the cumulative doses, the lower was the maximal contraction.

Interaction of Ca, Mg and ATP in glycerinated taenia coli of guinea pig

Ca sensitivity and energy dependence in the contractile proteins of the glycerinated taenia coli of guinea pig were studied. Above 1 X 10(-7)M Ca caused contraction in muscle which had been immersed in glycerol solution for 7 days in the presence of 5 mM Mg-ATP. Muscles which had been immersed in glycerol for 30 days had a higher Ca sensitivity than ones in glycerol for 7 days. When AMP or ADP (5, 10 MM) in place of ATP was added in the presence of 1 X 10(-6) M Ca and Mg(5, 10 mM), there was no contraction. Increasing the concentration of the same molar ratio of Mg-ATP from 1 to 20 mM in the presence of 1 X 10(-6) M Ca, the tension increased according to the Mg-ATP concentration. However, increase in Mg or ATP only in the presence of 1 X 10(-6) M Ca did not increase the tension. In conclusion, the three factors of Ca, Mg and ATP are essential for the activation of the contractile elements of glycerinated taenia. It is also suggested that the tension development in glycerinated taemia is controlled by the concentration of Ca and Mg-ATP complexes in intracellular fluid.

Inhibitory effects of caffeine on developed tension and calcium movement in guinea pig taenia coli in high-K medium

Since the correlation between the K-induced contracture and the Ca movement during the contrature in guinea-pig taenia coli has been clarified, the effects of caffeine were deemed worthy of investigation. The tonic contraction induced by 40 mM K disappeared within 5 min in the presence of caffeine above 7 mM. The inhibitory effect of caffeine was reversed by a high concentration of Ca added to the external medium. High-K added to the medium increased tissue Ca, Ca uptake and the size of cellular Ca fraction that did not exchange within 4 min (tightly bound fraction TBF), and it decreased Ca efflux. An application of 7 mM caffeine to the muscle treated with high-K for 30 min restored all parameters to the control level. Further, caffeine had no effect on the developed tension of the glycerinated taenia induced by Ca, Mg and ATP. It was observed that 14C-caffeine entered the cell in the presence of high-K. From these data, it is suggested that caffeine inhibits high-K induced contracture by inhibiting Ca influx into the contractile mechanism.

Histopathological studies of the nervous system tumors in rats induced by N-nitroso-methyl-urea

Histopathological examinations were made on tumors of the nervous system induced in rats of Donryu strain by weekly intravenous injections with N-nitroso-methyl-urea (NMU) or by a single administration of NMU through the mothers. A total of 176 neural and nonneural neoplasms were produced in this study. It was suggested that the fetal nervous system of Donryu rats was also highly susceptible to the oncogenic effects of NMU. Of these tumors produced, those of the peripheral nervous system amounted to 121, comprising 68.7% of the total number of the neoplasm. Microscopically, most of the nerve tumors showed the histology corresponding to that of human neurinomas. Many tumors, however, disclosed more or less anaplastic cytological appearance. Fifteen gliomas were produced in the brain and spinal cord. Microscopically, they were classified into mixed glioma, oligondendroglioma and anaplastic astrocytoma. The commonest brain tumors produced in rats from intravenously treated group were periventricular mixed gliomas, while gliomas in rats from transplacentably treated group showed an isomorphic histology with a close resemblance to that of oligodendroglioma.

[Early diagnosis and selection of operative approach for acoustic neuroma (author's transl)]

The recent advances of various diagnostic procedures made possible to detect intracanalicular neuroma in early stage. The operative results have been also greatly improved by transtemporal approach using surgical microscope and dental burr. In addition, the revised suboccipital approach contributed to obtain better operative results. Reviewing our clinical experiences with 15 cases operated from May 1969 to December 1971, appropriate combination of applicable diagnostic procedures and selection of operative method are discussed. Multiple audiologic examinations consisting of pure tone audiometry, speech discrimination, Békésy audiometry, alternate binaural loudness balance test, tone decay and uncomfortable lebel were performed in 11 cases. 9 of these cases manifested retrocochlear type of hearing loss. Spontaneous nystagmus and induced nystagmus, together with balance test, were evaluated for vestibular function. Bithermal caloric test disclosed unilateral canal paresis in all cases. In 13 cases, spontaneous nystagmus was observed. Analysis of optokinetic nystagmus using electronystagmography suggested tumor invasion to the brain stem and cerebellum. Tomography of the internal auditory canal showed abnormal findings in all cases. Cisternography with 2 ml of myodil was performed in 7 cases, all of which were diagnosed definitely by filling defect. Angiography showed abnormal vascular displacement with the tumor of size exceeding 3 cm in diameter. Translabyrinthine approach was performed in 5 cases. Suboccipital approach was applied in 6 cases. Combined approach of these two routes was used in 4 cases. 11 patients returned to their original work postoperatively. To obtain the correct diagnosis of acoustic neuroma in early stage, multiple audiologic examination are indispensable together with detailed vestibular function tests when the unilateral sensory neural hearing loss is suspected. Tomography of the internal auditory canal is also advisable as routine roentonologic study. If the clinical sign is confined to the 8th nerve only, myodil cisternography is useful, however, angiography is reliable in more advanced cases. When the tumor size is below 2 cm and signs of the spread to the brain stem, cerebellum or lower cranial nerves are lacking, translabyrinthine approach is indicated. Suboccipital approach is advisable for more advanced cases or undefinitive cases. Planning of combined approach of both routes is seemed to be not necessary in any case from our experience.

Optic organ and cervical proprioceptors in maintenance of body equilibrium

Two experiments were made on the functional correlation between the optic organ and the cervical proprioceptors in maintenance of body equilibrium. Experiment I: The effects of weak and strong electric stimulation of the deep nuchal muscles on changes in optokinetic nystagmus and optokinetic after-nystagmus were examined in adult non-albino rabbits with binocular vision. Experiment II: Experiment I was repeated on rabbits with monocular vision giving optokinetic stimulation moving from the side of the blindfolded eye to that of the open eye and applying only weak electric stimulation to the neck muscles. The results obtained were as follows: (1) Experiment I: Weak electric stimulation of the deep nuchal muscles of rabbits with binocular vision tended to promote optokinetic nystagmus with either no significant change or decrease in optokinetic after-nystagmus. Strong electric stimulation had the opposite effects, i.e., it tended to inhibit optokinetic nystagmus and activate optokinetic after-nystagmus. It also produced abnormal optokinetic nystagmus, such as the inversion phenomenon of optokinetic nystagmus and "optokinetic nystagmus firing". (2) Experiment II: Weak electric stimulation of the deep nuchal muscles of rabbits with monocular vision had similar effects to those in experiment I, but promotion of optokinetic nystagmus was less obvious, while activation of optokinetic after-nystagmus was more marked. In addition, the inversion phenomenon of optokinetic nystagmus developed even on weak electric stimulation. From these results the following conclusions were drawn: (1) The cervical proprioceptors can function in two mechanisms causing promotion and break down of equilibrium of the optokinetic system. (2) The cervical proprioceptors, as an organ of equilibrium, can exert two different actions on the optokinetic eye reflexes, i.e., they can promote optokinetic nystagmus and inhibit optokinetic after-nystagmus.

Fine structure of primary reticulum cell sacroma of the brain

An electron microscopic study was made on two cases of reticulum cell sarcoma (microglioma) of the brain. In both, the tumour was composed of several type of cells; cells with an undifferentiated appearance and cells with ultrastructural features of the reticulum cell and histiocyte. There seemed to be no significant difference in the fine structure between the tumour cells in reticulum cell sarcoma of the brain and extracerebral forms. The ultrastructures of a lymphosarcoma of the spinal epidural space was also examined and resembles that of such tumours occurring elsewhere in the body.