Showing papers in "Science in 1962"
1,059 citations
TL;DR: In an autoradiographic investigation, the production of brain lesions in rats was combined with intracranial injection of thymidine-H3, and nuclei of numerous glia cells were found labeled in brain regions associated with the traumatized areas.
Abstract: In an autoradiographic investigation, the production of brain lesions in rats was combined with intracranial injection of thymidine-H(3). Nuclei of numerous glia cells were found labeled in brain regions associated with the traumatized areas. In addition, some neurons and neuroblasts showed labeling, suggesting the possibility of proliferation of neurons in adult rats.
979 citations
TL;DR: In the article "Intracellular oxidation-reduction states in vivo," by B. Chance, P. Cohen, F. Jobsis, and B. Schoener, two errors occur.
Abstract: It now appears to be possible to continuously record changes in intracellular oxidation-reduction levels in terms of the fluorescence of reduced pyridine nucleotide in mitochondria of various tissues and organs in situ. Studies of kidney and brain cortex in the rat show that changes in fluorescence are not measurably affected by the presence of oxyhemoglobin. Nitrogen, sulfide, cyanide, and carbon monoxide cause increases in fluorescence to very nearly the same levels, and the increases are attributed to larger reduction of mitochondrial diphosphopyridine nucleotide. Amytal at a low blood concentration causes increased reduction in the kidney cortex, and at a high blood concentration, in the brain cortex. The qualitative response of the pyridine nucleotide to low oxygen concentrations shows the brain to be more sensitive than the kidney. The first measurable increase in pyridine nucleotide reduction observed on the brain occurs at a concentration of inspired oxygen of 8 percent. Breathing stops when the percentage increase of pyridine nucleotide reduction on the brain reaches about 90; at this point the percentage increase for the kidney is only about 30. This difference corresponds roughly to a tenfold difference in oxygen tension. Half-maximal increase in pyridine nucleotide reduction on the brain occurs at a concentration of inspired oxygen of about 4 percent and corresponds to an intracellular oxygen tension of about 0.2 mm (47).
909 citations
897 citations
TL;DR: The amplitude of electrical potentials generated in stressed bone is dependent upon the rate and magnitude of bony deformation, while polarity is determined by the direction of bending, while areas under compression develop negative potentials with respect to other areas.
Abstract: The amplitude of electrical potentials generated in stressed bone is dependent upon the rate and magnitude of bony deformation, while polarity is determined by the direction of bending. Areas under compression develop negative potentials with respect to other areas. Similar results were obtained both in living and dead bone. Removal of the inorganic fraction from bone abolishes its ability to generate stress potentials. It is probable that these potentials influence the activity of osseous cells directly. Furthermore, it is conceivable that they may direct, in some manner, the aggregation pattern of the macromolecules of the extracellular matrix.
723 citations
TL;DR: An operant behavioral study on morphine addiction utilized a self-injection technique for giving intravenous injections to relatively unrestrained rats, finding that Morphine was a reinforcer that produced almost immediate satiation.
Abstract: An operant behavioral study on morphine addiction utilized a self-injection technique for giving intravenous injections to relatively unrestrained rats. The rate of self-injection varied inversely with the dose. Morphine was a reinforcer that produced almost immediate satiation.
635 citations
TL;DR: An established line of fish cells has been propagated in vitro for 21 months and 48 subcultivations and important characteristics of the cells are described.
Abstract: An established line of fish cells has been propagated in vitro for 21 months and 48 subcultivations. Important characteristics of the cells are described.
592 citations
TL;DR: Research is urgently needed on the structure ofpure clay minerals and on the reactions of pure clay minerals with organic and inorganic materials.
Abstract: The structures of the clay minerals are reasonably well known, but greater detail and more precision are needed if the properties of clays and soils are to be fully understood. For example, the selective adsorptive and catalytic properties and the reaction with organic materials vary with the character of the clay mineral, but the structural factors that control such properties are not well understood. Research is urgently needed on the structure of pure clay minerals and on the reactions of pure clay minerals with organic and inorganic materials. Much past research on clay-mineral reactions has little fundamental value because the clay that was used was composed of a mixture of minerals which were not well characterized. It is not a simple matter to find pure samples of many of the clay minerals, and to a considerable extent progress depends on finding such pure minerals or preparing them in the laboratory.
562 citations
TL;DR: It was found that in hamsters injected intrapulmonarily with tissue culture fluid of human type 12 adenovirus within 24 hours after birth there was a very high incidence of malignant tumors at the site of injection in from 1 to 3 months.
Abstract: A new approach to the important but difficult task of revealing possible human tumor viruses has been presented in this article. By systematic testing of already known human viruses for oncogenic properties, it was found that in hamsters injected intrapulmonarily with tissue culture fluid of human type 12 adenovirus within 24 hours after birth there was a very high incidence of malignant tumors at the site of injection in from 1 to 3 months. The tumorinducing activity was not lost by filtration through Selas 02 filters or by tissue culture passages in HeLa cells. Tumors thus induced grew in, and killed, a high percentage of the unconditioned young adult hamsters into which they were transplanted. No such tumors occurred in hamsters injected with control tissue culture fluid or with culture fluids of the other viruses tested, or in control breeder hamsters. The possibility that contamination with polyoma virus and simian virus 40 might be responsible for the tumors induced was specifically excluded by a variety of tests. The possible involvement of still other, as yet unknown, contaminant viruses was excluded by a positive association of the tumor-inducing ability with the adenovirus content. Of eight human sera tested, only those four which neutralized the adenovirus-type cytopathic effect also neutralized the tumor-inducing effect. Of 700 human sera tested, 26 percent contained CPE-neutralizing antibodies for type 12 adenovirus at titers of 1:4 and higher (23).
516 citations
TL;DR: An attempt has been made to define quantitatively the architecture of airways and blood vessels of the human lung and it is suggested that morphometric studies conducted according to this general model may be useful in the anatomical description of other organs.
Abstract: An attempt has been made to define quantitatively the architecture of airways and blood vessels of the human lung. For this purpose five normal lungs from individuals aged 8 to 74 years were subjected to a dimensional analysis by several methods of measurement based on statistical principles. The elements of the "respiratory zone" may be regarded as randomly distributed in the lung. There are essentially the same number of alveoli (300 million), alveolar ducts (14 million), and capillary segments (280 billion) in all lungs. The dimensions of these architectural elements are shown to depend mainly on the size of the lung. The effect on these dimensions of such functional variables as the degree of inflation of the lung or of the filling of capillaries with blood are discussed. The alveolar and alveolar-capillary surface areas, which are of importance in the analysis of gas exchange between air and blood, are found to increase with the size of the lung. In our material, both varied in the range of 40 to 80 square meters. The elements of the conductive zone of the lung show a polar orientation. The airways have, on the average, 23 generations of dichotomous branching; the pulmonary arteries reach the precapillaries after about 28 generations. The average diameters of the airway and blood-vessel elements at each generation appear to follow the laws of "best" dimensions. The functional significance of this finding is discussed. It is suggested that morphometric studies conducted according to this general model may be useful in the anatomical description of other organs (16).
430 citations
TL;DR: Following intravenous infusion of tritiated norepinephrine, rat pineals were prepared for combined autoradiography and electron microscopy and Concentrations of photographic grains were observed only over regions of preterminal autonomic axons containing granulated vesicles, thereby directly demonstrating uptake of norpinephrine into these axons and strongly suggesting that their granulatedVesicles contain nore Pinephrine.
Abstract: Following intravenous infusion of tritiated norepinephrine, rat pineals were prepared for combined autoradiography and electron microscopy. Concentrations of photographic grains were observed only over regions of preterminal autonomic axons containing granulated vesicles, thereby directly demonstrating uptake of norepinephrine into these axons and strongly suggesting that their granulated vesicles contain norepinephrine.
TL;DR: Food acts via the ventromedial hypothalamus to inhibit not only feeding, but also lateral hypothalamic self-stimulation in rats bearing four, intrahypothalamic electrode-cannulas for electrical stimulation or chemical injection.
Abstract: Hypothalamic sites which control feeding exert a corresponding control over lateral hypothalamic self-stimulation. This was demonstrated in rats bearing four, intrahypothalamic electrode-cannulas for electrical stimulation or chemical injection. Self-stimulation of the lateral hypothalamus was inhibited by ventromedial excitation or by excessive feeding. Both self-stimulation and feeding were accelerated (disinhibited) by ventromedial ablation or anesthetization. Thus food acts via the ventromedial hypothalamus to inhibit not only feeding, but also lateral hypothalamic self-stimulation.
TL;DR: The distribution of response latencies and the percentage performance curve of a classical conditioning group, by comparison with a control group, indicated that the extension of the nictitating membrane elicited by a puff of air to the cornea was successfully conditioned to a previously neutral stimulus.
Abstract: The distribution of response latencies and the percentage performance curve of a classical conditioning group, by comparison with a control group, indicated that the extension of the nictitating membrane elicited by a puff of air to the cornea was successfully conditioned to a previously neutral stimulus.
TL;DR: Infant and adult rhesus monkeys manifested persistent avoidance responses to "looming" but not to the inverse, indicating that this visual stimulus alone is a strong exciter of avoidance, and the response appears early in life.
Abstract: The approach of an object corresponds with a spatiotemporal optical stimulus consisting of a symmetrical expansion of a closed contour in the field of view. The visual equivalent of impending collision was isolated and compared with its sequential inversion. Infant and adult rhesus monkeys manifested persistent avoidance responses to "looming" but not to the inverse. This visual stimulus alone is a strong exciter of avoidance, and the response appears early in life.
TL;DR: The "staggerer" mutant is recognized by its staggering gait, mild tremor, hypotonia, and small size.
Abstract: The "staggerer" mutant is recognized by its staggering gait, mild tremor, hypotonia, and small size. Symptoms develop during postnatal weeks 1 to 4 and remain stationary thereafter. The cerebellar cortex is grossly underdeveloped, with too few granule cells and unaligned Purkinje cells. Genetic linkage studies and neuropathological findings distinguish staggerer from other known mutants.
TL;DR: In this paper, the cell edge of the high pressure form is 4.280 A, the theoretical density is 6.912, and the enthalpy of transition is 785 cal/mole.
Abstract: Zinc oxide exists in a sodium chloride structure form in the 100-kilobar pressure range. The cell edge of the high pressure form is 4.280 A, the theoretical density is 6.912, and the enthalpy of transition is 785 cal/mole.
TL;DR: It is proposed that proteins of spindle fiber nature exist in cortical cytoplasm of plant cells and are active in the control of wall texture and cell form.
Abstract: The control of the cylindrical cell form in plants appears to reside in the orientation of the reinforcing cellulose microfibrils in the side walls. In elongating cells the fibrils are typically transverse. Control of new synthesis of oriented wall texture is shown to be in turn related to the orientation of cytoplasmic elements in the cell periphery. Three properties of these cytoplasmic elements have been deduced from polarization optical properties of treated and normal cell walls. These deduced properties— namely, possession of a long axis and the ability to build microfibrils perpendicular to it, a tendency to cross-bond to make a parallel array, and a sensitivity of this alignment to colchicine—are all well-known properties of mitotic spindle and phragmoplast fibers which form the cross-wall after mitosis. It is proposed that proteins of spindle fiber nature exist in cortical cytoplasm of plant cells and are active in the control of wall texture and cell form.
TL;DR: High-resolution electron microscopy has revealed that the regions of contact between smooth muscle cells from dog intestine are areas of fusion of adjacent cell membranes.
Abstract: High-resolution electron microscopy has revealed that the regions of contact between smooth muscle cells from dog intestine are areas of fusion of adjacent cell membranes. For morphological and functional reasons this type of contact between excitable cells has been termed a nexus.
TL;DR: The feeding system of the lateral hypothalamus is one among a larger group of places where stimulation causes primary rewarding effects, and with electrodes in these same areas, food deprivation often caused a major increment in the self-stimulation rate.
Abstract: Electrodes were implanted in the lateral hypothalamic feeding system; animals were subjected to both feeding and motivational tests. All animals that demonstrated stimulus-bound feeding behavior also showed high self-stimulation rates. As it was impossible to produce the feeding response without simultaneously producing the rewarding effect of hypothalamic stimulation, it was concluded that the feeding system of the lateral hypothalamus is one among a larger group of places where stimulation causes primary rewarding effects. With electrodes in these same areas, food deprivation often caused a major increment in the self-stimulation rate.
TL;DR: The zona pellucida may be removed from all stages of the mouse egg by digestion with pronase, and functions of the zona include maintenance of the normal cleavage pattern and prevention of egg fusion.
Abstract: The zona pellucida may be removed from all stages of the mouse egg by digestion with pronase. Cumulus and corona cells are also dispersed by the enzyme. No change in membrane disgestibility occurs at fertilization. In tests thus far of two-cell eggs and later stages, development continues. Blastocysts exhibit "hatching" behavior despite absence of the zona. Functions of the zona include maintenance of the normal cleavage pattern and prevention of egg fusion.
TL;DR: The induction the induction and suppression of breast cancer in albino rats is described to permit the analysis of the mechanisms of the causes and extinction of cancer 2 of the central problems in cancer research.
Abstract: This article describes the induction the induction and suppression of breast cancer in albino rats; the study was conducted to permit the analysis of the mechanisms of the causes and extinction of cancer 2 of the central problems in cancer research. A single feeding of 20 mg of 712 dimethylbenz(a)anthracene (712-DMBA) dissolved in sesame oil developed mammary cancer in all of over 700 healthy female rats of the Sprague-Dawley strain. The mammary cancer evoked by the aromatic hydrocarbons were all rather similar in cytologic appearance and all had the cellular pattern of papillary adenocarcinoma. Experiments also showed that while 712-DMBA and 2-aminophenanthrene were strong carcinogens benz(a)anthracene and phenanthrene did not evoke mammary cancer. It appears that the methyl and amnio groups convert the otherwise inactive parent molecular species to powerful carcinogens. 3 factors seem to determine mammary carcinogenicity in polynuclear aromatic hydrocarbons: 1) the electron transfer 2) the geometric factor and 3) the molecular thickness. Regression of mammary cancer has been induced by 2 types of alteration of the endocrine status the withdrawal of the hormones essential for the life and growth of the cancer usually done through ovariectomy on the administration of appropriate hormones. In an experiment female rats previously induced with mammary cancer through administration of 712-DMBA were given for 30 days 20 mcg of estradiol-17 and 4 mg of progesterone. In a group of 100 rats treated this way 52 were free from cancer at necropsy whereas their control companions succumbed to cancer. This experiment was repeated under more rigorous conditions with rats with large mammary cancers; the results were equally successful.
TL;DR: A preliminary summary of the data received from the Mariner II solar plasma experiment for the period 29 August through 31 October 1962 is presented.
Abstract: A preliminary summary of the data received from the Mariner II solar plasma experiment for the period 29 August through 31 October 1962 is presented. During this period there was always a measurable flow of plasma from the direction of the sun. The velocity of this ion motion was generally in the range 400 to 700 km/sec. Time variations, plasma density, and ion temperatures are also discussed.
TL;DR: It was found that the manipulated rats showed a significant elevation of corticosteroids as early as 15 seconds after shock, whereas the nonmanipulated subjects did not show a significant Elevation of steroids until 5 minutes after a brief shock.
Abstract: Circulating corticosteroids were measured after a brief electric shock in rats which were manipulated during infancy. When compared to nonmanipulated controls it was found that the manipulated rats showed a significant elevation of corticosteroids as early as 15 seconds after shock, whereas the nonmanipulated subjects did not show a significant elevation of steroids until 5 minutes after a brief shock. Further, the levels of corticosteroids were consistently higher in the manipulated subjects over a 15-minute period.
TL;DR: Findings support the work of others on the mode of action of actinomycin D in vivo and can be reversed by adding deoxyribonucleic acid to the enzymatic reaction.
Abstract: Minute amounts of actinomycin D inhibit the synthesis of ribonucleic acid by nuclear extracts of HeLa cells in a ribonucleic acid-synthesizing system that is dependent on deoxyribonucleic acid and requires the presence of all four ribonucleoside triphosphates. The inhibition can be reversed by adding deoxyribonucleic acid to the enzymatic reaction. These findings support the work of others on the mode of action of actinomycin D in vivo.
TL;DR: This relationship suggests that a "reward" is simply any response that is independently more probable than another response.
Abstract: Parameters were identified for the rat which both made drinking more probable than running and running more probable than drinking. In the same subjects, depending upon which parameters were used, running reinforced drinking and drinking reinforced running. This relationship suggests that a "reward" is simply any response that is independently more probable than another response.