bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbocyclic Arabinofuranosyladenine (Cyclaradine): Efficacy Against Genital Herpes in Guinea Pigs
Authors: Vince Robert , Daluge Susan , Lee Heejoo , Shannon William M. , Arnett Gussie , Schafer Thomas W. , Nagabhushan Tattanahalli L. , Reichert Paul , Tsai Hsingan
Published: October 2006

Carbocyclic arabinofuranosyladenine (cyclaradine), a novel nucleoside analog with such desired features as hydrolytic and enzymatic stability, adenosine deaminase resistance, and low systemic toxicity, inhibited the replication of herpes simplex virus types 1 and 2. The 5′-methoxyacetate prodrug form exhibited significant efficacy in the topical treatment of genital infections by herpes simplex virus type 2.
Opioid Peptides Mediate the Suppressive Effect of Stress on Natural Killer Cell Cytotoxicity
Authors: Shavit Yehuda , Lewis James W. , Terman Gregory W. , Gale Robert Peter , Liebeskind John C.
Published: October 2006

The cytotoxic activity of natural killer cells was investigated in rats subjected to one of two inescapable footshock stress paradigms, both of which induce analgesia, but only one via activation of opioid mechanisms. Splenic natural killer cell activity was suppressed by the opioid, but not the nonopioid, form of stress. This suppression was blocked by the opioid antagonist naltrexone. Similar suppression of natural killer activity was induced by high doses of morphine. These results suggest that endogenous opioid peptides mediate the suppressive effect of certain forms of stress on natural killer cell cytotoxicity.
Antigenic Similarity Between Cells Transformed by Ultraviolet Radiation in Vitro and in vivo
Authors: Fisher Michael S. , Kripke Margaret L. , Chan Gerald L.
Published: October 2006

Cells of the 10T 1/2 mouse fibroblast line transformed in vitro by ultraviolet radiation are antigenically similar to those from skin cancers produced in mice by repeated exposure to ultraviolet radiation. Both types of tumor cells grew preferentially in ultraviolet-irradiated syngeneic mice relative to untreated animals, and both were recognized by ultraviolet radiation-induced tumor-specific suppressor lymphocytes. These properties were not shared by 10T 1/2 cells transformed in vitro by x-rays or 3-methylcholanthrene.
Dioxin in Soil: Bioavailability After Ingestion by Rats and Guinea Pigs
Authors: McConnell E. E. , Lucier G. W. , Rumbaugh R. C. , Albro P. W. , Harvan D. J. , Hass J. R , Harris M. W.
Published: October 2006

Soil environmentally contaminated with 2,3,7,8-tetrachlorodibenzo-
p
-dioxin (TCDD) was given by gavage to guinea pigs and rats. The development of a characteristic clinicopathologic syndrome in guinea pigs, the induction of aryl hydrocarbon hydroxylase in rats, and the presence of TCDD in the livers of both species show that TCDD in soil exhibits high biological availability after ingestion.
Coronary Arteries of Cardiac Patients Are Hyperreactive and Contain Stores of Amines: A Mechanism for Coronary Spasm
Authors: Kalsner Stanley , Richards Robert
Published: October 2006

Coronary arteries from hearts of cardiac patients contain significantly higher concentrations of histamine than do those from noncardiac patients. The coronary vessels of cardiac patients are also hyperresponsive to histamine and serotonin. These differences between groups of patients suggest an explanation for coronary artery spasm in heart disease.
Synthesis of Compounds with Properties of Leukotrienes C
4
and D
4
in Gerbil Brains After Ischemia and Reperfusion
Authors: Moskowitz Michael A. , Kiwak Kevin J. , Hekimian Karl , Levine Lawrence
Published: October 2006

6-Sulfidopeptide-containing leukotriene-like immunoreactivity was synthesized in gerbil forebrains after bilateral common carotid occlusion and reperfusion. At 5, 10, or 15 minutes of ischemia, concentrations increased significantly and became more marked on reperfusion. Immunoreactivity was highest in forebrain gray matter and was below the detection limit of the assay in brain regions remote from the zone of ischemia. In vitro experiments with vascular cells and organ cultures of cerebral arteries indicate that the cerebral blood vessel wall is not a major source of biosynthetic activity in the brain. These experiments demonstrate leukotriene biosynthesis by the brain. Because synthesis occurs during ischemia and reperfusion and because leukotrienes are potent vasoconstrictors and promoters of tissue edema, they may play a role in the pathophysiology of cerebral ischemia.
Forebrain Lesions Disrupt Development But Not Maintenance of Song in Passerine Birds
Authors: Bottjer Sarah W. , Miesner Elizabeth A. , Arnold Arthur P.
Published: October 2006

The magnocellular nucleus of the anterior neostriatum is a forebrain nucleus of passerine birds that accumulates testosterone and makes monosynaptic connections with other telencephalic nuclei that control song production in adult birds. Lesions in the magnocellular nucleus disrupted song development in juvenile male zebra finches but did not affect maintenance of stable song patterns by adult birds. These results represent an instance in which lesions of a discrete brain region during only a restricted phase in the development of a learned behavior cause permanent impairment. Because cells of the magnocellular nucleus accumulate androgens these findings raise the possibility that this learning is mediated by hormones.
Chromosomal Location of Human Metallothionein Genes: Implications for Menkes' Disease
Authors: Schmidt Carl J. , Hamer Dean H. , McBride O. Wesley
Published: October 2006

Human metallothioneins are encoded by a complex multigene family. The chromosomal location of these genes has been determined by gel transfer hybridization analysis of the DNA from human-rodent cell hybrids. Chromosome 16 contains a cluster of metallothionein sequences, including two functional metallothionein I genes and a functional metallothionein II gene. The remaining sequences, including a processed pseudogene, are dispersed to at least four other autosomes. The absence of metallothionein sequences from the X chromosome indicates that Menkes' disease, an X-linked disorder of copper metabolism, affects metallothionein expression by a trans-acting mechanism.
Clustering of Human H1 and Core Histone Genes
Authors: Carozzi Nadine , Marashi Farhad , Plumb Mark , Zimmerman Selma , Zimmerman Arthur , Coles L. S. , Wells J. R. E. , Stein Gary , Stein Janet
Published: October 2006

An H1 histone gene was isolated from a 15-kilobase human DNA genomic sequence. The presence of H2A, H2B, H3, and H4 genes in this same 15-kilobase fragment indicates that mammalian core and H1 histone genes are clustered.
Raman Spectroscopy of a Coal Liquid Shows That Fluorescence Interference Is Minimized with Ultraviolet Excitation
Authors: Asher Sanford A. , Johnson Craig R.
Published: October 2006

The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene. The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures.
Calcium Source for Excitation-Contraction Coupling in Myocardium of Nonhibernating and Hibernating Chipmunks
Authors: Kondo Noriaki , Shibata Shoji
Published: October 2006

The amplitude of the early plateau phase of the action potential and the slow action potential of cardiac muscle were much lower in hibernating chipmunks than in nonhibernating chipmunks. The frequency-dependent contraction was decreased in hibernating animals but increased in nonhibernating animals. Caffeine caused a negative inotropic effect in hibernating animals but a positive inotropic effect in nonhibernating animals. Ryanodine caused greater inhibition in hibernating animals than in nonhibernating animals. These results suggest that the respective roles of the sources of calcium for cardiac excitation-contraction coupling are changed during hibernation.
Genetic Basis of XX Male Syndrome and XX True Hermaphroditism: Evidence in the Dog
Authors: Selden Jules R. , Wachtel Stephen S. , Koo Gloria C. , Haskins Mark E. , Patterson Donald F.
Published: October 2006

Serological analysis of white blood cells from the members of a family of American cocker spaniels indicates that a form of abnormal sexual development, in which individuals with a female karyotype have testes or ovotestes, is caused by anomalous transmission of male-determining H-Y genes.
Immunology of Archaebacteria That Produce Methane Gas
Authors: Conway de Macario Everly , Wolin Meyer J. , Macario Alberto J. L.
Published: October 2006

The antigenic map of 17 methanogenic bacteria representing the entire range of available species was determined by multiple assay with antibody probes. Four major clusters of antigenically related strains coincide with the families proposed on the basis of 16
S
ribosomal RNA analysis. Immunological mapping uncovered relationships not yet shown by other methods and allowed identification and classification of two new bacterial isolates.
Inhibition of Purine Nucleoside Phosphorylase by 8-Aminoguanosine: Selective Toxicity for T Lymphoblasts
Authors: Kazmers Irene S. , Mitchell Beverly S. , Dadonna Peter E. , Wotring Linda L. , Townsend Leroy B. , Kelley William N.
Published: October 2006

The guanosine analog 8-aminoguanosine is an effective inhibitor of the purine degradative enzyme purine nucleoside phosphorylase, both in vitro and in intact lymphoid cells. In a human lymphoblast tissue culture system, 8-aminoguanosine, in combination with low concentrations of 2′-deoxyguanosine, causes toxicity toward T cells but not B cells. The selective T cell toxicity correlates with increased accumulation of deoxyguanosine triphosphate in the treated T lymphoblasts.
Cell Adhesion Molecules
Authors: Edelman Gerald M.
Published: October 2006

It has been proposed that cell-cell recognition occurs by means of local cell surface modulation of a small number of proteins rather than by expression of large numbers of different cell surface markers. Several different cell adhesion molecules (CAM's) have now been found in a number of vertebrate species in different tissues such as liver and striated muscle and even in a single complex structure such as the brain, where different molecules specific for neurons and glia have been identified. The neuron-specific molecule is involved in early embryonic events but also mediates neurite fasciculation, neuromuscular interaction, and orderly layering of neural tissue. It undergoes local surface modulation with loss of sialic acid during development. A failure of this process is closely correlated with connectional disorders in the
staggerer
mutant of the mouse. The accumulated data on this and other CAM's favor modulation theories rather than strict chemoaffinity theories of cell-cell recognition.
Independent Pathways for Secretion of Cholesterol and Apolipoprotein E by Macrophages
Authors: Basu Sandip K. , Goldstein Joseph L. , Brown Michael S.
Published: October 2006

Cholesterol-loaded macrophages secrete cholesterol and apolipoprotein E. The current studies show that this secretion occurs by two independent pathways. In the absence of serum, the cells secrete apolipoprotein E, but not cholesterol. In the presence of monensin (an inhibitor of protein secretion), the cells secrete cholesterol, but little apolipoprotein E. After secretion, apolipoprotein E and cholesterol associate with high-density lipoprotein to form a particle that can deliver cholesterol to the liver by receptor-mediated endocytosis. We conclude that apolipoprotein E does not function to remove cholesterol from macrophages but rather to participate in "reverse cholesterol transport."
Hysteresis in the Force-Calcium Relation in Muscle
Authors: Ridgway Ellis B. , Gordon Albert M. , Martyn Donald A.
Published: October 2006

Calcium ions activate muscle contraction. The mechanism depends on the calcium sensitivity of the proteins that regulate contraction. Evidence is presented for the reverse phenomenon, where contraction modulates calcium sensitivity. Increasing the force level increased calcium sensitivity in intact fibers showing that the relation between force and calcium is not unique. A particular calcium concentration can maintain a higher force level than it can create. The results were confirmed in skinned fiber experiments. Transient reduction of the force led to a transient reduction in calcium binding, suggesting a simple mechanism for the hysteresis.
The Nature of Technological Hazard
Authors: Hohenemser C. , Kates R. W. , Slovic P.
Published: October 2006

Technological hazards are evaluated in terms of quantitatively expressed physical, biological, and social descriptors. For each hazard a profile is constructed that considerably extends the conventional definition of risk. The profile, which is termed hazardousness, was understood in pilot experiments on perception and appeared to capture a large fraction of lay people's concern with hazard. It also suggests an orderly method for establishing priorities for the management of hazards.
Psychological Stress Induces Sodium and Fluid Retention in Men at High Risk for Hypertension
Authors: Light Kathleen C. , Koepke John P. , Obrist Paul A. , Willis Park W.
Published: October 2006

Exposure to competitive mental tasks significantly reduced the urinary sodium and fluid excreted by young men with one or two hypertensive parents or with borderline hypertension. In this high-risk group, the degree of retention was directly related to the magnitude of heart rate increase during stress, suggesting common mediation by way of the sympathetic nervous system. Thus, psychological stress appears to induce changes in renal excretory functions that may play a critical role in long-term blood pressure regulation.
Schistosoma mansoni
: Identification of Chemicals That Attract or Trap Its Snail Vector,
Biomphalaria glabrata
Authors: Uhazy Leslie S. , Tanaka Richard D. , MacInnis Austin J.
Published: October 2006

A new bioassay for chemical attractants of aquatic snails demonstrated that
Biomphalaria glabrata
could be attracted to or trapped in the vicinity of homogenates of lettuce. Fractionation of homogenates revealed the amino acids glutamate and proline as the primary attractants. Attraction was specific for the L form of glutamate. Proline appeared to stimulate reproductive activity. Glutathione, γ-aminobutyric acid, and a number of other compounds had no effect. Extracts of lyophilized snail tissue also attracted other snails and may thus contain pheromones. These results permit formulation and testing of controlled-release attractants designed to overcome the repellant effects of slow-release molluscicides, as well as the design of stimulants to be used with no-release poisons.
Secretion in Mast Cells Induced by Calcium Entrapped Within Phospholipid Vesicles
Authors: Theoharides Theoharis C. , Douglas William W.
Published: October 2006

Purified mast cells secreted histamine when fused to phospholipid vesicles containing calcium but not magnesium or potassium. Microscopic observation revealed highly localized exocytotic responses involving punctate extrusion of individual granules. Calcium delivered from the vesicles to the cytoplasm is apparently a sufficient stimulus to initiate exocytosis. The results support the calcium hypothesis of stimulus-secretion coupling.
High Fetal Estrogen Concentrations: Correlation with Increased Adult Sexual Activity and Decreased Aggression in Male Mice
Authors: vom Saal Frederick S. , Grant William M. , McMullen Carol W. , Laves Kurt S.
Published: October 2006

In the house mouse (
Mus musculus
), fetuses may develop in utero next to siblings of the same or opposite sex. The amniotic fluid of the female fetuses contains higher concentrations of estradiol than that of male fetuses. Male fetuses that developed in utero between female fetuses had higher concentrations of estradiol in their amniotic fluid than males that were located between other male fetuses during intrauterine development. They were also more sexually active as adults, less aggressive, and had smaller seminal vesicles than males that had developed between other male fetuses in utero. These findings raise the possibility that during fetal life circulating estrogens may interact with circulating androgens both in regulating the development of sex differences between males and females and in producing variation in phenotype among males and among females.
Serum Factor Supporting Long-Rerm Survival of Rat Central Neurons in Culture
Authors: Kaufman Lawrence M. , Barrett John N.
Published: October 2006

Gel filtration of serum at
p
H 3.6 yielded a fraction that supported long-term (months) survival of dissociated rat central neurons in monolayer culture more reliably than the traditionally used unfractionated serum. The cultures remained neuron-rich, because this fraction did not support the proliferation of glia and fibroblasts that occurs in whole serum. With an apparent molecular weight of 55,000 and an isoelectric point of 5.6, the active factor (or factors) in this fraction is distinct from any well-defined growth factor.
Animal Anorexias
Authors: Mrosovsky N. , Sherry David F.
Published: October 2006

Eating very little in the presence of food or failure to search for food has been documented in various species during the hibernation season, incubation, molting, and defense of the territory or harem. At these times feeding competes with other, more important activities. One way to avoid conflicts between feeding and these other activities is to lower the programmed weight or set-point for body fat. Experiments on mammalian hibernators and incubating birds provide evidence that set-points are indeed lowered. Failure to eat in these two examples depends on anorexia, loss of appetite. A review of other examples suggests that conceptualization in terms of lowered set-points provides a unified and testable way of understanding many naturally occurring instances of fasting in the animal kingdom. Finally, spontaneous animal anorexias are contrasted with attempts by people to lose weight.
Suppression of Immunity by Stress: Effect of a Graded Series of Stressors on Lymphocyte Stimulation in the Rat
Authors: Keller Steven E. , Weiss Jay M. , Schleifer Steven J. , Miller Neil E. , Stein Marvin
Published: October 2006

In rats a graded series of stressors produced progressively greater suppression of lymphocyte function, as measured by the number of circulating lymphocytes and by phytohemagglutinin stimulation of lymphocytes in whole blood and isolated cultures. This evidence suggests that stress suppresses immunity in proportion to the intensity of the stressor.
A New Laser Scanning System for Measuring Action Potential Propagation in the Heart
Authors: Dillon S. , Morad M.
Published: October 2006

A rapid laser scanning system was developed to map the spread of excitation in amphibian and mammalian hearts stained with fluorescent dye. Isochronic maps of conduction were constructed by timing the upstroke of the optical action potential; 128 sites could be scanned in 4 milliseconds. The accuracy of this technique was verified by recording simultaneously from 16 unipolar electrodes placed in different areas of the heart. Conducted action potentials in normal frog heart propagated at 0.1 meter per second. Propagation of action potentials was also monitored in ischemic cat heart, in which both driven and arrhythmic action potential upstrokes could be tracked. The results suggest that this system is capable of scanning the normal and abnormal spread of electrical activity in the heart.
Tonicity Effects on Intact Single Muscle Fibers: Relation Between Force and Cell Volume
Authors: Gulati J. , Babu A.
Published: October 2006

Contraction of isolated, intact frog muscle fibers under increasing tonicity of the external solution was studied by adding (i) effectively impermeant sodium chloride and sucrose and (ii) permeant potassium chloride. Force of isometric contraction decreased as a function of tonicity, independent of the permeability of the solute. In contrast, cell volume changed with tonicity in impermeant solutes and was constant with potassium chloride. The results are evidence that ionic strength in the sarcoplasm directly influences the contraction mechanism. Also, the findings show that force development is unaffected by changes in fiber volume, suggesting that the force per cross-bridge is constant at different distances between the thin and thick myofilaments. Finally, in light of the length-force relation, the results support the idea that cross-bridges are independent force generators.
Silicone Rubber Substrata: A New Wrinkle in the Study of Cell Locomotion
Authors: Harris Albert K. , Wild Patricia , Stopak David
Published: October 2006

When tissue cells are cultured on very thin sheets of cross-linked silicone fluid, the traction forces the cells exert are made visible as elastic distortion and wrinkling of this substratum. Around explants this pattern of wrinkling closely resembles the "center effects" long observed in plasma clots and traditionally attributed to dehydration shrinkage.
Laser Microsurgery in Cell and Developmental Biology
Authors: Berns Michael W. , Aist J. , Edwards J. , Strahs K. , Girton J. , McNeill P. , Rattner J. B. , Kitzes M. , Hammer-Wilson M. , Liaw L.-H. , Siemens A. , Koonce M. , Peterson S. , Brenner S. , Burt J. , Walter R. , Bryant P. J. , van Dyk D. , Coulombe J. , Cahill T. , Berns G. S.
Published: October 2006

New applications of laser microbeam irradiation to cell and developmental biology include a new instrument with a tunable wavelength (217- to 800-nanometer) laser microbeam and a wide range of energies and exposure durations (down to 25 × 10
-12
second). Laser microbeams can be used for microirradiation of selected nucleolar genetic regions and for laser microdissection of mitotic and cytoplasmic organelles. They are also used to disrupt the developing neurosensory appendages of the cricket and the imaginal discs of
Drosophila
.
Rheumatoid Factor-Like Immunoglobulin M Protects Previously Uninfected Rat Pups and Dams from
Trypanosoma lewisi
Authors: Clarkson Allen B. , Mellow George H.
Published: October 2006

The serum of lactating rats that have never been infected with the protozoan parasite
Trypanosoma lewisi
contains a rheumatoid factor-like immunoglobulin M (IgM). This IgM amplifies a specific immunoglobulin G (IgG) response to the parasite and accounts for the unusual resistance of previously uninfected lactating rats and their suckling pups to infection with
T. lewisi
. A similar rheumatoid factor-like IgM, which is induced late in the usual course of infection with
T. lewisi
in nonlactating rats, amplifies an earlier IgG response and terminates the infection. To our knowledge, this is the first description of a rheumatoid factor, which is classified as an autoimmune antibody, acting in a protective manner.
Oxidized Proteins in Erythrocytes Are Rapidly Degraded by the Adenosine Triphosphate-Dependent Proteolytic System
Authors: Goldberg Alfred L. , Boches Francee S.
Published: October 2006

The rate of protein degradation in rabbit erythrocytes is normally very low. However, when cells were exposed to agents that oxidize cell proteins (nitrite or phenylhydrazine), the degradation of erythrocyte proteins to amino acids increased 7- to 33-fold. This effect was inhibited by the reducing agent methylene blue. Stimulation of proteolysis also occurred in cell extracts and resulted from the production of substrates (damaged proteins) rather than from activation of proteases. Inhibitors of glycolysis and of the soluble adenosine triphosphate-dependent proteolytic pathway decreased the protein degradation induced by nitrite, whereas inhibitors of lysosomal proteolysis had no effect. Thus, the adenosine triphosphate-dependent proteolytic system is present in mature red cells where it may help protect against the accumulation of proteins damaged by oxidation or other means.
Plasmodium falciparum
Gametocytes from Culture in Vitro Develop to Sporozoites That Are Infectious to Primates
Authors: Campbell Carlos C. , Collins William E. , Nguyen-Dinh Phuc , Barber Ann , Broderson J. Roger
Published: October 2006

Gametocytes of two strains of the human malaria parasite
Plasmodium falciparum
have been produced in high density by means of a continuous-flow cultivation system. The gametocytes of these two strains infected a mean of 36 percent and 71 percent, respectively, of
Anopheles freeborni
mosquitoes that fed on a suspension of red blood cells containing the cultured gametocytes. Sporozoites harvested from the infected mosquito salivary glands were infective to the chimpanzee (
Pan troglodytes
) and the owl monkey (
Aotus trivirgatus
).
Aphagia and Adipsia After Preferential Destruction of Nerve Cell Bodies in Hypothalamus
Authors: Grossman Sebastian P. , Dacey Dennis , Halaris Angelos E. , Collier Timothy , Routtenberg Aryeh
Published: October 2006

Microinjections of the excitatory neurotoxin kainic acid into the lateral hypothalamus of rats produced a period of aphagia and adipsia. Kainate-treated rats displayed transient motor effects during the first hours after the injection but did not show the persisting sensory-motor and arousal disturbances typically observed in animals with electrolytic lesions in this part of the hypothalamus. Histological examination revealed a significant reduction in the number of nerve cell bodies in the lateral hypothalamus. Silver-stained material indicated no evidence of damage to fiber systems passing through the affected region. Assays of dopamine in hypothalamus, striatum, and telencephalon did not indicate significant differences between experimental and control animals. These results are in agreement with recent reports of the anatomical and biochemical effects of intracerebral kainic acid injections and suggest that the observed effect on feeding behavior is related to the destruction of neurons in the lateral hypothalamus.
In Vivo Mapping of Local Cerebral Blood Flow by Xenon-Enhanced Computed Tomography
Authors: Gur David , Good Walter F. , Wolfson Sidney K. , Yonas Howard , Shabason Leonard
Published: October 2006

A noninvasive technique has been developed to measure and display local cerebral blood flow (LCBF) in vivo. In this procedure, nonradioactive xenon gas is inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computerized tomography. The time-dependent xenon concentrations in various anatomical units in the brain are used to derive both the local partition coefficient and the LCBF. Functional mapping of blood flow with excellent anatomical specificity has been obtained in the baboon brain. The response of LCBF to stimuli such as changes in carbon dioxide concentrations as well as the variability in LCBF in normal and diseased tissue can be easily demonstrated. This method is applicable to the study of human physiology and pathologic blood flow alterations.
The Origin of Man: A Chromosomal Pictorial Legacy
Authors: Yunis Jorge J. , Prakash Om
Published: October 2006

Man, gorilla, and chimpanzee likely shared an ancestor in whom the fine genetic organization of chromosomes was similar to that of present man. A comparative analysis of high-resolution chromosomes from orangutan, gorilla, chimpanzee, and man suggests that 18 of 23 pairs of chromosomes of modern man are virtually identical to those of our "common hominoid ancestor," with the remaining pairs slightly different. From this lineage, gorilla separated first, and three major chromosomal rearrangements presumably occurred in a progenitor of chimpanzee and man before the final divergence of these two species. A precursor of the hominoid ancestor and orangutan is also assumed.
New Dopaminergic and Indoleamine-accumulating Cells in the Growth Zone of Goldfish Retinas After Neurotoxic Destruction
Authors: Negishi Koroku , Teranishi Tsunenobu , Kato Satoru
Published: October 2006

Juvenile goldfish were allowed to grow for 3 months after dopaminergic or indoleamine-accumulating cells in their retinas had been destroyed by intravitreal injection of 6-hydroxydopamine or 5,7-dihydroxytryptamine, respectively. New cells of each type were found growing in concentric rings at the margin of the retina. To compensate for the loss of dopaminergic innervation in retinas treated with 6-hydroxydopamine, cells in the growth zone appeared to proliferate at a higher rate than those in untreated retinas and long processes were extended into the retina by the first dopaminergic cells to appear.
Neurons in the Rat Dentate Gyrus Granular Layer Substantially Increase During Juvenile and Adult Life
Authors: Bayer Shirley A. , Yackel James W. , Puri Prem S.
Published: October 2006

Volumetric estimates of the total number of granule cells in rats 30, 120, 200, and 365 days old increase linearly by approximately 35 to 43 percent between 1 month and 1 year. Total volume of the granular layer also grows linearly during that time. These results demonstrate a numerical increase in a neuronal population during adulthood in the mammalian brain.
H-2
Histocompatibility Region: Influence on the Murine Glucocorticoid Receptor and Its Response
Authors: Gupta Chhanda , Goldman Allen
Published: October 2006

The influence of the
H-2
histocompatibility complex on glucocorticoid receptor levels, and the biochemical response of glucocorticoid action measured as the degree of inhibition of prostaglandin production, has been studied in the mouse thymus and lung. The B10A (
H-2
a
) strain of mice has significantly higher glucocorticoid receptor levels and a significantly greater biochemical response to glucocorticoid than the B10 (
H-2
b
) strain, which differs from B10A within the
H-2
complex only. Thus, the anti-inflammatory hormone response of glucocorticoids is correlated to hormone receptor level, both of which are influenced by the
H-2
locus.
Noise-Induced Hearing Loss Can Alter Neural Coding and Increase Excitability in the Central Nervous System
Authors: Willott James F. , Lu Shao-Ming
Published: October 2006

Responses of auditory neurons in the inferior colliculi of mice were studied longitudinally before and shortly after each animal was exposed to intense noise. Noise exposure caused expected losses in auditory sensitivity, but in 31 percent of the neurons studied, unexpected alterations of temporal patterns of action potentials were observed: certain suprathreshold stimuli that had evoked only transient "onset" responses or inhibition of spontaneous discharges prior to noise exposure came to elicit sustained excitation after exposure. Thus, noise-induced hearing loss can be associated with increases in neural responsivity and alterations of normal neural coding processes.
Sexual Dimorphism in the Human Corpus Callosum
Authors: de Lacoste-Utamsing Christine , Holloway Ralph L.
Published: October 2006

Preliminary observations suggest a sex difference in the shape and surface area of the human corpus callosum. The sexual dimorphism is striking in the splenium, the caudal or posterior portion of the corpus callosum. The female splenium is both more bulbous and larger than the male counterpart. Since peristriate, parietal, and superior temporal fibers course through the splenium, this finding could be related to possible gender differences in the degree of lateralization for visuospatial functions.
Neonatal Treatment with Antiserum to Prolactin Lowers Blood Pressure in Rats
Authors: Mills David E. , Buckman Maire T. , Peake Glenn T.
Published: October 2006

Prolactin administration reportedly increases blood pressure in rats and rabbits. To study the effects of prolactin deficiency on blood pressure, rats were given saline, normal rabbit serum, or rabbit antiserum to rat prolactin on postnatal days 2 to 5. Both males and females given antiserum had significantly lower blood pressure at 14 weeks than rats given saline or normal rabbit serum. Blood pressure differences between females given antiserum and females given saline disappeared during and following pregnancy. The antiserum also lowered the concentration of prolactin in plasma 49 percent in males and decreased the prolactin response to ether stress in both sexes. These results suggest that endogenous prolactin is involved in blood pressure regulation.
Adrenal Medullary Enkephalin-Like Peptides May Mediate Opioid Stress Analgesia
Authors: Lewis James W. , Tordoff Michael G. , Sherman Jack E. , Liebeskind John C.
Published: October 2006

Different patterns of foot shock activate opioid and nonopioid mechanisms of stress analgesia in the rat. Opioid, but not nonopioid, stress analgesia is reduced by adrenal demedullation and denervation and is potentiated by reserpine, a drug known to increase concentrations of adrenal medullary enkephalin-like peptides. It is suggested that adrenal enkephalins mediate opioid stress analgesia.
Psoralen Phototoxicity: Correlation with Serum and Epidermal 8-Methoxypsoralen and 5-Methoxypsoralen in the Guinea Pig
Authors: Kornhauser Andrija , Wamer Wayne G. , Giles Albert L.
Published: October 2006

Serum and epidermal concentrations of 8-methoxypsoralen and 5-methoxypsoralen 2 hours after oral administration to guinea pigs were determined by high-performance liquid chromatography. A linear relation was found between the serum and epidermal concentrations of 8-methoxypsoralen. In addition, a relation was found between serum concentrations of 5-methoxypsoralen and 8-methoxypsoralen and the appearance of phototoxicity. The lower phototoxicity of orally administered 5-methoxypsoralen as compared to 8-methoxypsoralen in the guinea pig appears to be due to its reduced concentrations in the epidermis, the primary site of the phototoxic events.
Abnormal Development of Kitten Retino-Geniculate Connectivity in the Absence of Action Potentials
Authors: Archer Steven M. , Dubin Mark W. , Stark Louisa A.
Published: October 2006

Action potentials were silenced in one eye of neonatal kittens by repeated intraocular injections of tetrodotoxin for 5 to 8 weeks. After tetrodotoxin blockade was allowed to wear off, receptive field properties of individual relay cells in the lateral geniculate nucleus were examined. The many ON-OFF and binocular fields found in the layers that receive input from the treated eye suggest that these cells had extremely abnormal retino-geniculate synaptic connections. These effects were different in kind from those seen after deprivation rearing that does not silence action potentials. Lack of action potential activity was concluded to lead to abnormal development in the central nervous system.
Damage to Hypothalamic Dopaminergic Neurons Is Associated with Development of Prolactin-Secreting Pituitary Tumors
Authors: Sarkar Dipak K. , Gottschall Paul E. , Meites Joseph
Published: October 2006

Old female rats with spontaneous prolactin-secreting pituitary tumors (prolactinomas) and young females with prolactinomas produced by prolonged estrogen treatment had damaged tuberoinfundibular dopaminergic neurons. Since these neurons inhibit the function of pituitary prolactin-secreting cells, their destruction may lead to development of prolactinomas.
Cassava: A Basic Energy Source in the Tropics
Authors: Cock James H.
Published: October 2006

Cassava (
Manihot esculenta
) is the fourth most important source of food energy in the tropics. More than two-thirds of the total production of this crop is used as food for humans, with lesser amounts being used for animal feed and industrial purposes. The ingestion of high levels of cassava has been associated with chronic cyanide toxicity in parts of Africa, but this appears to be related to inadequate processing of the root and poor overall nutrition. Although cassava is not a complete food it is important as a cheap source of calories. The crop has a high yield potential under good conditions, and compared to other crops it excels under suboptimal conditions, thus offering the possibility of using marginal land to increase total agricultural production. Breeding programs that bring together germ plasm from different regions coupled with improved agronomic practices can markedly increase yields. The future demand for fresh cassava may depend on improved storage methods. The markets for cassava as a substitute for cereal flours in bakery products and as an energy source in animal feed rations are likely to expand. The use of cassava as a source of ethanol for fuel depends on finding an efficient source of energy for distillation or an improved method of separating ethanol from water.
Decrease in Adrenergic Axon Sprouting in the Senescent Rat
Authors: Scheff Stephen W. , Bernardo Larry S. , Cotman Carl W.
Published: October 2006

When the septal area in young adult rats is denervated by a lesion of the fimbria-fornix, adrenergic fibers proliferate within the denervated area. The same operation performed on aged animals gives rise to a qualitatively similar but quantitatively less pronounced response. This reduction in reactive growth may reflect a decreased capacity of the aged brain to remodel its circuitry and restore lost function.
Center-Surround Organization of Auditory Receptive Fields in the Owl
Authors: Knudsen Eric I/ , Konishi Masakazu
Published: October 2006

The spatial receptive fields of specialized auditory units in the midbrain of the barn owl (
Tyto alba
) contain two functionally antagonistic areas: an excitatory center and an inhibitory surround. The response of these units represents the balance of acoustic activation of the two areas, which in turn depends upon the location, intensity, and spectral content of the sound stimulus.
Phase Shifting Circadian Rhythms Produces Retrograde Amnesia
Authors: Tapp Walter N. , Holloway Frank A.
Published: October 2006

Phase shifting circadian rhythms in rats shortly after passive avoidance training impaired their performance on retention tests. The amnesia was not due to simple performance deficits accompanying the "jet lag" effects of phase shifting or to differences in lighting or circadian phase at training and at testing. Amnesia was associated with specific rhythm reentrainment patterns. These data indicate that disrupting circadian organization can produce retrograde amnesia in rats.
Tumor Rejection in Rats After Inescapable or Escapable Shock
Authors: Visintainer Madelon A. , Volpicelli Joseph R. , Seligman Martin E. P.
Published: October 2006

Rats experienced inescapable, escapable, or no electric shock 1 day after being implanted with a Walker 256 tumor preparation. Only 27 percent of the rats receiving inescapable shock rejected the tumor, whereas 63 percent of the rats receiving escapable shock and 54 percent of the rats receiving no shock rejected the tumor. These results imply that lack of control over stressors reduces tumor rejection and decreases survival.
Postnatal Gonadal Steroid Effects on Human Behavior
Authors: Rubin Robert T. , Reinisch June M. , Haskett Roger F.
Published: October 2006

Gonadal steroid hormones, active during fetal life, continue after the birth of a fetus to influence the central nervous system and affect behavior. The characteristically different circulating concentrations of male and female steroid hormones in men and women appear to be partial determinants of certain sexually dimorphic behaviors, interacting in a complex way with psychological and sociocultural factors as well as with other biological factors. This interaction is highlighted in research on testosterone and aggression in men, mood and the menstrual cycle in women, and pubertal sex role reversal in pseudohermaphrodites.
Gene for Neuraminidase Activity on Mouse Chromosome 17 Near H-2: Pleiotropic Effects on Multiple Hydrolases
Authors: Womack James E. , Yan Denise Lu Shun , Potier Michel
Published: October 2006

The low activity of liver neuraminidase that is characteristic of mouse strain SM/J is inherited as a single gene on chromosome 17, near the major histocompatibility complex. This gene, neuraminidase-1 (
Neu-1
), is represented by the low activity allele
Neu-1
s
in SM/J and the high activity allele
Neu-1
b
in C57BL/6J and most other strains. Previously described variations in the posttranslational processing of acid phosphatase, α-mannosidase, arylsulfatase-B, and α-glucosidase are attributed to pleiotropic effects of this gene.
Auditory Intensity Discrimination After Selective Loss of Cochlear Outer Hair Cells
Authors: Prosen Cynthia A. , Moody D. B. , Stebbins W. C. , Hawkins J. E.
Published: October 2006

The contributions of the inner and outer hair cells of the mammalian cochlea to auditory intensity discrimination were evaluated in a combined behavioral-anatomical study of the guinea pig. Intensity difference thresholds were unchanged from baseline values after selective destruction of outer hair cells, suggesting that those cells are unnecessary for normal intensity discrimination.
Human Leukocyte Interferon Purified to Homogeneity
Authors: Rubinstein Menachem , Rubinstein Sara , Familletti Philip C. , Gross Mitchell S. , Miller Robert S. , Waldman Alan A. , Pestka Sidney
Published: October 2006

One of the species of human interferon produced by incubation of leukocytes with Newcastle disease virus was purified to homogeneity. It exhibited one peak of activity coinciding with a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
Intrinsic Birefringence Signal Preceding the Onset of Contraction in Heart Muscle
Authors: Weiss R. , Morad M.
Published: October 2006

An intrinsic birefringence signal with two components occurring before sarcomere shortening was measured in mammalian cardiac muscle. The second component was sensitive to the inotropic state of the muscle as affected by external calcium concentration and epinephrine but not by changes of resting length. The second component was absent in frog heart. These results suggest that the second component of the birefringence signal reflects the activity of the sarcoplasmic reticulum related to excitation-contraction coupling processes occurring prior to onset of contraction in mammalian cardiac muscle.
The Golgi Apparatus: Two Organelles in Tandem
Authors: Rothman James E.
Published: October 2006

The Golgi apparatus consists of distinct
cis
and
trans
compartments that may act sequentially to refine the protein export of the endoplasmic reticulum by removing escaped endoplasmic reticulum proteins. Refinement may be a multistage process akin to fractional distillation; the stack of cisternae comprising the
cis
Golgi may be the plates in this distillation tower. The
trans
Golgi, consisting of the last one or two cisternae, may be the receiver that collects from the
cis
Golgi only its most refined fraction for later distribution to specific locations throughout the cell.
Spatial Knowledge and Geometric Representation in a Child Blind from Birth
Authors: Landau Barbara , Gleitman Henry , Spelke Elizabeth
Published: October 2006

A series of experiments demonstrated that a congenitally blind 2 ½-year-old child—as well as sighted but blindfolded children and adults—can determine the appropriate path between two objects after traveling to each of those objects from a third object. This task requires that the child detect the distances and the angular relationship of the familiar paths and that she derive therefrom the angle of the new path. Our research indicates that the locomotion of the young blind child is guided by knowledge of the Euclidean properties of a spatial layout and by principles for making inferences based on those properties.
Calcium-Induced Cell Death: Susceptibility of Cardiac Myocytes Is Age-Dependent
Authors: Chizzonite Richard A. , Zak Radovan
Published: October 2006

Rat hearts perfused with calcium-free media exhibit an age-dependent response when a normal calcium concentration is restored to the perfusate. The response of 15- and 26-day hearts is an explosive cell death which includes immediate cessation of contractile activity, as well as release of large amounts of creatine phosphokinase activity and myoglobin. Between birth and 15 days of age, the sensitivity of the heart to this calcium-induced cellular disruption changes from a relative insensitivity before 6 days of age to a slight but constant sensitivity from 7 to 11 days of age, and to full sensitivity at 15 days of age. This pattern of sensitivity may be due to the rapid increase in complexity and quantity of the membrane systems of cardiac myocytes during the first 15 days of growth.
Efficiency of Human Visual Signal Discrimination
Authors: Burgess A. E. , Wagner R. F. , Jennings R. J. , Barlow H. B.
Published: October 2006

We have measured the overall statistical efficiency of human subjects discriminating the amplitude of visual pattern signals added to noisy backgrounds. By changing the noise amplitude, the amount of intrinsic noise can be estimated and allowed for. For a target containing a few cycles of a spatial sinusoid of about 5 cycles per degree, the overall statistical efficiency is as high as 0.7 ± 0.07, and after correction for intrinsic noise, efficiency reaches 0.83 ± 0.15. Such a high figure leaves little room for residual inefficiencies in the neural mechanisms that handle these patterns.
Voltage Clamp Studies in Macrophages from Mouse Spleen Cultures
Authors: Gallin Elaine K.
Published: October 2006

Voltage clamp studies of macrophages from cultures of mouse spleen macrophages produced N-shaped steady-state current-voltage curves containing a region of negative slope resistance. Some macrophages exhibit two stable states of membrane potential, having current-voltage relationships that cross the voltage axis at three points. Outward currents that turn on at voltages of +15 millivolts or greater were noted in several cells. The addition of barium chloride to the bathing medium abolished the negative slope resistance and reduced the inward currents in response to hyperpolarizing voltage steps. These data provide direct evidence that macrophages exhibit at least two different voltage-dependent conductances and demonstrate that voltage clamp techniques can be useful in studying the membrane properties of leukocytes.
Diagnosis of Cardiovascular Disease by Digital Subtraction Angiography
Authors: Mistretta Charles A. , Crummy Andrew B.
Published: October 2006

Recent advances in real-time digital video processing have led to a practical method for intravenous arteriography. The digital subtraction technique, which detects small differences in the concentration of the iodinated contrast material injected, is relatively safe and does not usually require hospitalization of the patient. The technique can thus be used for serial evaluation of various clinical problems and for studying the natural history of certain disease processes, as well as for following therapeutic endeavors.
Regulation of Leucine Metabolism in Man: A Stable Isotope Study
Authors: Matthews D. E. , Bier D. M. , Rennie M. J. , Edwards R. H. T. , Halliday D. , Millward D. J. , Clugston G. A.
Published: October 2006

Leucine catabolism is regulated by either of the first two degradative steps: (reversible) transamination to the keto acid or subsequent decarboxylation. A method is described to measure rates of leucine transamination, reamination, and keto acid oxidation. The method is applied directly to humans by infusing the nonradioactive tracer, L-[
15
N,1-
13
C]leucine. Leucine transamination was found to be operating several times faster than the keto acid decarboxylation and to be of equal magnitude in adult human males under two different dietary conditions, postabsorptive and fed. These results indicate that decarboxylation, not transamination, is the rate-limiting step in normal human leucine metabolism.