bluuebunny/crossref_metadata_2025 huggingface dataset:
Some Computer-Based Developments in Sociology
Authors: Heise David R. , Simmons Roberta G.
Published: October 2006

Sociological data sets are now being computer analyzed by means of a variety of sophisticated procedures, to produce results that reflect the intricacy of social life. Computers also are being used to conduct simulations of social processes based on mathematical models and to collect the data for analysis. Portable computers allow computing power to be used in field studies, and the relatively low cost of computers is expanding the range of sociologists who use them. While opening up new research opportunities, computers also bring certain problems for social researchers and teachers.
A Specific 37,000-Dalton Protein That Accumulates in Regenerating but Not in Nonregenerating Mammalian Nerves
Authors: Müller Hans Werner , Gebicke-Härter Peter J. , Hangen Donald H. , Shooter Eric M.
Published: October 2006

A 37-kilodalton protein is synthesized at higher rates in the peripheral and central nervous system of newborn rats than in adult animals. As a specific response to denervation, the synthesis of the 37-kilodalton protein is increased in the mature peripheral and central nervous system; however, this protein accumulates only in the peripheral nervous system. The differences in accumulation of the protein correlate with the apparent differences in the ability of peripheral and central axons to regenerate. The synthesis of the 37-kilodalton protein is inhibited when proper innervation or reinnervation is established.
Sonar Tracking of Horizontally Moving Targets by the Big Brown Bat
Eptesicus fuscus
Authors: Masters W. Mitch , Moffat Anne J. M. , Simmons James A.
Published: October 2006

When following a moving target, echolocating bats (
Eptesicus fuscus
) keep their heads aimed at the target's position. This tracking behavior seems not to involve predicting the target's trajectory, but is achieved by the bat's pointing its head at the target's last known position. The bat obtains frequent position updates by emitting sonar signals at a high rate. After the lag between head and target positions and the nonunity tracking gain were corrected for, bats' tracking accuracy in the horizontal plane was ± 1.6°.
Rate Theories and Puzzles of Hemeprotein Kinetics
Authors: Frauenfelder Hans , Wolynes Peter G.
Published: October 2006

The binding of dioxygen and carbon monoxide to heme proteins such as myoglobin and hemoglobin has been studied with flash photolysis. At temperatures below 200 K, binding occurs from within the heme pocket and, contrary to expectation, with nearly equal rates for both ligands. This observation has led to a reexamination of the theory of the association reaction taking into account friction, protein structure, and the nature of electronic transitions. The rate coefficients for the limiting cases of large and small friction are found with simple arguments that use characteristic lengths and times. The arguments indicate how transition state theory as well as calculations based on nonadiabatic perturbation theory, which is called the Golden Rule, may fail. For ligand-binding reactions the data suggest the existence of intermediate states not directly observed so far. The general considerations may also apply to other biomolecular processes such as electron transport.
Molecular Resolution Electron Micrographs of Monolamellar Paraffin Crystals
Authors: Zemlin F. , Reuber E. , Beckmann E. , Zeitler E. , Dorset D. L.
Published: October 2006

A liquid helium-cooled cryoelectron microscope, operated to expose the specimen to only a very low electron dose, was used to obtain structural images of monolamellar
n
-tetratetracontane (n-C
44
H
90
) crystals at 0.25-nanometer resolution. These results are in contrast to earlier predictions that such extremely beam-sensitive materials could not be studied directly at this level of detail. Analysis of the resultant lattice images gives direct evidence for crystal bending as well as direct visualization of edge dislocations in this material.
Noninvasive Study of High-Energy Phosphate Metabolism in Human Heart by Depth-Resolved
31
P NMR Spectroscopy
Authors: Bottomley Paul A.
Published: October 2006

Phosphorus-31 nuclear magnetic resonance (NMR) spectra showing the relative concentrations of high-energy phosphate metabolites have been recorded noninvasively from the human heart in vivo. Spectral data were spatially localized by combining a pulsed magnetic field gradient with surface NMR excitation-detection coils. The location of the selected spectral region was determined by conventional proton NMR imaging immediately before examination by phosphorus-31 NMR spectroscopy.
Transfection of v-
ras
H
DNA into MCF-7 Human Breast Cancer Cells Bypasses Dependence on Estrogen for Tumorigenicity
Authors: Kasid Attan , Lippman Marc E. , Papageorge Alex G. , Lowy Douglas R. , Gelmann Edward P.
Published: October 2006

The natural history of estrogen-responsive breast cancers often involves a phenotypic change to an estrogen-unresponsive, more aggressive tumor. The human breast cancer cell line, MCF-7, which requires estradiol for tumor formation in vivo and shows growth stimulation in response to estradiol in vitro, is a model for hormone-responsive tumors. The v-
ras
H
onc gene was transfected into MCF-7 cells. The cloned MCF-
ras
transfectants, which expressed the v-
ras
H
messenger RNA and v-
ras
H
p21 protein (21,000 daltons), were characterized. In contrast to the parental cell line, MCF-
ras
cells no longer responded to exogenous estrogen in culture and their growth was minimally inhibited by exogenous antiestrogens. When tested in the nude mouse, the MCF-
ras
cells were fully tumorigenic in the absence of estrogen supplementation. Thus, cells acquiring an activated onc gene can bypass the hormonal regulatory signals that trigger the neoplastic growth of a human breast cancer cell line.
Fluorescence Digital Imaging Microscopy in Cell Biology
Authors: Arndt-Jovin Donna J. , Robert-Nicoud Michel , Kaufman Stephen J. , Jovin Thomas M.
Published: October 2006

Developments in microscope, sensor, and image-processing technologies have led to integrated systems for the quantification of low-light-level emission signals from biological samples. Specificity is provided in the form of monoclonal antibodies and other ligands or enzyme substrates conjugated with efficient fluorophores. Fluorescent probes are also available for cellular macromolecular constituents and for free ions of biological interest such as H
+
and Ca
2+
. The entire spectrum of photophysical phenomena can be exploited. Representative data are presented from studies of DNA conformation and architecture in polytene chromosomes and from studies of receptor-mediated endocytosis, calcium distribution, and the organization of the contractile apparatus in muscle cells.
Visual Input to the Visuomotor Mechanisms of the Monkey's Parietal Lobe
Authors: Yin T. C. T. , Mountcastle V. B.
Published: October 2006

A newly identified class of neurons of the parietal cortex, studied in waking monkeys (
Macaca mulatta
), is activated by visual stimuli, perhaps via the retino-collicular visual pathway. This afferent input is thought to provide the visual cues activating the visuomotor mechanisms of the parietal lobe for the direction of visual attention.
Environmental Hydrocarbons Produce Degeneration in Cat Hypothalamus and Optic Tract
Authors: Schaumburg Herbert H. , Spencer Peter S.
Published: October 2006

2,5-Hexanedione, the principal neurotoxic metabolite of the industrial solvents
n
-hexane and methyl n-butyl ketone causes axonal degeneration in the mammillary body and visual nuclei of cats. Prolonged, low-level exposure to hydrocarbons in the environment may cause premature deterioration in areas of the human brain vital for perception and behavior.
Watching Fat Digestion
Authors: Patton John S. , Carey Martin C.
Published: October 2006

During fat digestion a number of physicochemical events can be seen directly by light microscopy. Under simulated physiological conditions, hydrolysis of emulsified fat droplets by human pancreatic lipase in the presence of colipase and bile salt micelles proceeds with the sequential formation of two visible product phases. A lamellar liquid crystalline or crystalline phase containing calcium and ionized fatty acid forms first; this is followed by the production of a "viscous isotropic" phase composed predominantly of monoglycerides and protonated fatty acids.
Dexamethasone Stimulation of Metallothionein Synthesis in HeLa Cell Cultures
Authors: Karin Michael , Herschman Harvey R.
Published: October 2006

HeLa cells in culture synthesize metallothionein. To investigate the effects of glucocorticoids on metallothionein synthesis we adapted HeLa cells to growth in a defined medium lacking hydrocortisone. In this defined medium, containing 1.5 × 10
-6
M
Zn
2+
, dexamethasone (10
-6
M
) caused a five- to sixfold increase in the synthesis of metallothionein. Progesterone (10
-5
M
), a known antagonist of glucocorticoids, inhibited this response by 50 percent.
Rhythms in Human Performance: 1 ½-Hour Oscillations in Cognitive Style
Authors: Klein Raymond , Armitage Roseanne
Published: October 2006

Performance on verbal and spatial matching tasks was assessed every 15 minutes for 8 hours. Significant 90- to 100-minute oscillations were observed for each task. These oscillations were 180° out of phase, supporting the hypothesis that in humans the basic rest activity cycle involves alternating activation of processing systems residing in the two cerebral hemispheres.
Dendritic Mechanisms Underlying Penicillin-Induced Epileptiform Activity
Authors: Wong R. K. S. , Prince D. A.
Published: October 2006

The action of penicillin on synaptically evoked dendritic activity was examined with the use of hippocampal slice preparations. Orthodormic activation of CA1 pyramidal neurons produced an excitatory-inhibitory postsynaptic potential sequence recorded intracellularly in the dendrites. Treatment with penicillin resulted in the appearance of spontaneous and synaptically evoked multipeaked field potentials and associated depolarization shifts and spike burst generation in CA1 cells. Intracellular recordings revealed that penicillin produced no detectable change in passive membrane properties of the postsynaptic dendrites. However, the inhibitory postsynaptic potential was suppressed by penicillin, resulting in the release of intrinsic dendritic burst firing during synaptic activation. These findings emphasize the role of normal patterns of dendritic burst generation in the production of intense neuronal discharge during penicillin-induced epileptiform activities.
Iodide-Induced Hypothyroidism: A Potential Hazard During Perinatal Life
Authors: Theodoropoulos Theodor , Braverman Lewis E. , Vagenakis Apostolos G.
Published: October 2006

The administration of iodide to pregnant and nursing rats induces hypothyroidism in the term fetus and neonatal rat through age 10 days as indicated by an increase in the serum concentration of thyroid-stimulating hormone and a decrease in the serum of thyroxine and triiodothyronine. Thyroid function returned to normal from age 18 through 60 days in spite of continued iodide administration, strongly suggesting that resistance to the inhibitory effect of iodide on thyroid hormone synthesis is developed at approximately 18 days of age. This perinatal rat model can be used to study the mechanisms responsible for iodide-induced hypothyroidism and goiter in human newborns whose mothers received iodide-containing medications during pregnancy.
Bitter Taste of Saccharin Related to the Genetic Ability to Taste the Bitter Substance 6-
n
-Propylthiouracil
Authors: Bartoshuk Linda M.
Published: October 2006

Bitter taste thresholds for 6-
n
-propylthiouracil are bimodally distributed, dividing subjects into tasters and nontasters. Their taste worlds differ with regard to the sweetness of sucrose and saccharin and to the bitterness of saccharin. These differences suggest that nontasters tend to perceive less bitterness in saccharin at concentrations used in beverages.
Functional Organization of Lateral Geniculate Cells Following Removal of Visual Cortex in the Newborn Kitten
Authors: Murphy E. Hazel , Kalil Ronald
Published: October 2006

When the visual cortex of a newborn kitten is removed, most neurons in the dorsal lateral geniculate nucleus degenerate, but a small population of large cells is spared. Electrophysiological recording revealed that detailed visual topography in the nucleus is abnormal and that single cells have unusually large receptive fields. These results suggest that optic axons deprived of their normal synaptic targets rearrange their connections to converge on local surviving neurons.
Gamma Rays: Further Evidence for Lack of a Threshold Dose for Lethality to Human Cells
Authors: Furcinitti Paul S. , Todd Paul
Published: October 2006

In experiments designed to measure human cell survival with ± 2 percent accuracy it was found that low doses (21 to 87 rad) of γ-rays inactivated the colony-forming ability of cultured human cells with a probability of 0.00226 ± 0.00012 per rad. There appears to be no threshold for the lethality of radiation to human cells in vitro.
Time-Resolved Europium(III) Excitation Spectroscopy: A Luminescence Probe of Metal Ion Binding Sites
Authors: Horrocks William DeW. , Sudnick Daniel R.
Published: October 2006

A laser-induced luminescence technique is introduced for probing the structure and equilibria of lanthanide complexes and lanthanide ion binding to macromolecules. The method involves the excitation of the
7
F
0
→
5
D
0
transition between nondegenerate levels in the europium(III) ion by means of an intense pulsed dye laser source. Excitation profiles obtained by scanning the laser through the transition region reveal distinct peaks characteristic of individual europium(III) ion environments. The technique may be used to characterize the species present in complex equilibria in solution or to study europium(III) binding to macromolecules. Distinct europium(III) binding sites in thermolysin with long and short excited state lifetimes are observed.
Induction of Mitosis in Mature Neurons in Central Nervous System by Sustained Depolarization
Authors: Cone Clarence D. , Cone Charlotte M.
Published: October 2006

DNA synthesis and mitosis have been induced in vitro in fully differentiated neurons from the central nervous system by depolarization with a variety of agents that produce a sustained rise in the intracellular sodium ion concentration and a decrease in the potassium ion concentration. Depolarization was followed in less than 1 hour by an increase in RNA synthesis and in 3 hours by initiation of DNA synthesis. Apparently normal nuclear mitosis ensued, but cytokinesis was not completed in most cells; this resulted in the formation of binucleate neurons. The daughter nuclei each contained the same amount of DNA as the diploid preinduction parental neurons; this implies that true mitogenic replication was induced.
Lymphocyte-Induced Angiogenesis in Tumor-Bearing Mice
Authors: Sidky Y. A. , Auerbach R.
Published: October 2006

The presence of a growing tumor can lead to a significant curtailment of a graft-versus-host reaction as measured by the ability of allogeneic spleen cells to induce a host vascular response. This interference with the normal pattern of immunological reactions may be a reason for the survival of tumors in an immunologically alien environment.
Small Cell Carcinoma of the Lung: Macrophage-Specific Antigens Suggest Hemopoietic Stem Cell Origin
Authors: Ruff Michael R. , Pert Candace B.
Published: October 2006

Four surface antigens previously recognized only in macrophages are present on human small cell lung carcinoma cells and tumors. Cancerous cells may arise from macrophage precursors in bone marrow, and these precursors migrate to lung to participate in the repair of damaged tissue produced by continuous heavy smoking. The characteristic presence of neuropeptides such as bombesin in small cell carcinoma, when considered along with these findings, presents new possibilities for the role of such peptides in nervous, endocrine, and immune system function.
The Twitch in Horses: A Variant of Acupuncture
Authors: Lagerweij Evert , Nelis Pieter C. , Wiegant Victor M. , van Ree Jan M.
Published: October 2006

The twitch procedure in horses attenuates the increase in the heart rate evoked by pain-inducing stimuli and the reaction of the animals to such stimuli. Endorphin systems are probably involved in the effectiveness of the twitch, since its action is blocked by naloxone and its application increases plasma concentrations of immunoreactive β-endorphin. The mode of action of the twitch cannot be explained by the generally accepted theory of divertive pain and may resemble that of classical acupuncture.
Calcium-Mediated Reduction of Ionic Currents: A Biophysical Memory Trace
Authors: Alkon Daniel L.
Published: October 2006

Learning behavior similar to vertebrate classical conditioning was demonstrated for the mollusc
Hermissenda crassicornis
. Postsynaptic membrane changes within well-defined neural systems that mediate the learning play a casual role in recording the learned association for later recall. Specific ionic currents in neural tissue undergo transformations lasting days after associative training with physiologic stimuli. During acquisition the intracellular calcium increases; this increase is accompanied by specific potassium current reduction that lasts for days after conditioning. The increase of calcium enhances calmodulin-dependent phosphorylation of proteins that either regulate or are part of ion channels. These currents and the conditions that precede their transformation occur in many types of vertebrate neurons, and hence this biophysical basis of
Hermissenda
learning could have relevance for species other than the gastropod studied.
Comparison of the Distribution of Dynorphin Systems and Enkephalin Systems in Brain
Authors: Watson Stanley J. , Khachaturian Henry , Akil Huda , Coy David H. , Goldstein Avram
Published: October 2006

A study of the anatomical distribution of the endogenous opioid dynorphin in rat brain showed that the peptide is localized in a widespread system with multiple cell groups and projections. This network is revealed by the use of multiple antiserums against dynorphin and can be distinguished from the system containing methionine-enkephalin and leucine-enkephalin, which is mapped by the use of antiserums against the enkephalins and biosynthetically related peptides in the adrenal. It thus appears that the brain contains at least three separate opioid neuronal networks: an enkephalin family with components similar to those found in the adrenal, a β-endorphin family, and a dynorphin family.
Message Transmission: Receptor Controlled Adenylate Cyclase System
Authors: Schramm Michael , Selinger Zvi
Published: October 2006

The adenylate cyclase system is composed of an activating hormone or neurotransmitter (H), its receptor (R), the guanosine triphosphate (GTP) binding protein (G
s
), and the catalytic unit (C). The activation of the receptor R involves a transient change in conformation, from a loose binding of the neurotransmitter H to an extremely tight interaction, termed locking. The system is regulated in the activation steps and also by three deactivation processes. A guanosine triphosphatase activity is built into the G
s
protein so that the active G
sGTP
has only a limited lifetime during which it is able to activate C. In addition, the continued occupation of R by H causes desensitization of R. Finally, there are inhibitory receptors, such as α-adrenergic and opiate receptors, which inhibit the adenylate cyclase by way of a specific GTP binding protein (Gi). Yet to be determined are the conformational transformations of pure R on binding of an agonist or a partial agonist; the genes that code for the many different receptors that activate the adenylate cyclase, and the possibility that the G components interact with systems in the cell other than the adenylate cyclase.
Brain Peptides as Neurotransmitters
Authors: Snyder Solomon H.
Published: October 2006

Numerous peptides appear to be neurotransmitter candidates in the brain. Some, such as the opioid peptide enkephalins, neurotensin, and substance P, were first isolated from the brain. Peptides, such as cholecystokinin and vasoactive intestinal polypeptide, were known as intestinal hormones and later recognized as brain constituents. Certain hypothalamic-releasing hormones, pituitary peptides, and blood-derived peptides like angiotensin II and bradykinin, may also be central neurotransmitters. The diversity of localization of these peptides throughout the brain implies a multiplicity of potential roles.
Reactivation of an Inactive Human X Chromosome: Evidence for X Inactivation by DNA Methylation
Authors: Mohandas T. , Sparkes R. S. , Shapiro L. J.
Published: October 2006

A mouse-human somatic cell hybrid clone, deficient in hypoxanthine-guanine phosphoribosyltransferase (HPRT) and containing a structurally normal inactive human X chromosome, was isolated. The hybrid cells were treated with 5-azacytidine and tested for the reactivation and expression of human X-linked genes. The frequency of HPRT-positive clones after 5-azacytidine treatment was 1000-fold greater than that observed in untreated hybrid cells. Fourteen independent HPRT-positive clones were isolated and analyzed for the expression of human X markers. Isoelectric focusing showed that the HPRT expressed in these clones is human. One of the 14 clones expressed human glucose-6-phosphate dehydrogenase and another expressed human phosphoglycerate kinase. Since 5-azacytidine treatment results in hypomethylation of DNA, DNA methylation may be a mechanism of human X chromosome inactivation.
Two Novel Classes of Small Ribonucleoproteins Detected by Antibodies Associated with Lupus Erythematosus
Authors: Lerner Michael R. , Boyle John A. , Hardin John A. , Steitz Joan A.
Published: October 2006

The RNP and Sm antigens recognized by lupus erythematosus antibodies are located on discrete particles containing single small nuclear RNA's complexed with proteins. The antigens Ro and La are also on ribonucleoproteins. The small RNA's in ribonucleoproteins with Ro are discrete, like those associated with RNP and Sm; in contrast, ribonucleoproteins with La contain a striking highly banded spectrum of small RNA's from uninfected cells as well as virus-associated RNA from adenovirus-infected cells.
Power Spectrum Analysis of Heart Rate Fluctuation: A Quantitative Probe of Beat-to-Beat Cardiovascular Control
Authors: Akselrod Solange , Gordon David , Ubel F. Andrew , Shannon Daniel C. , Berger A. Clifford , Cohen Richard J.
Published: October 2006

Power spectrum analysis of heart rate fluctuations provides a quantitative noninvasive means of assessing the functioning of the short-term cardiovascular control systems. We show that sympathetic and parasympathetic nervous activity make frequency-specific contributions to the heart rate power spectrum, and that renin-angiotensin system activity strongly modulates the amplitude of the spectral peak located at 0.04 hertz. Our data therefore provide evidence that the renin-angiotensin system plays a significant role in short-term cardiovascular control on the time scale of seconds to minutes.
Neuronal Cell Thy-1 Glycoprotein: Homology with Immunoglobulin
Authors: Williams Alan F. , Gagnon Jean
Published: October 2006

The amino acid sequences of mouse brain Thy-1 glycoproteins are shown to be homologous to those of variable-region immunoglobulin domains. There is also good homology with constant domains and β
2
-microglobulin; overall the results suggest that Thy-1 may be like the primordial immunoglobulin domain. Preliminary evidence for an invertebrate Thy-1 homolog supports this possibility.
The Retina of the Newborn Human Infant
Authors: Abramov Israel , Gordon James , Hendrickson Anita , Hainline Louise , Dobson Velma , LaBossiere Eileen
Published: October 2006

We have examined a pair of eyes from a normal, full-term infant who died at 8 days as a result of accidental injury. Eyes were obtained immediately after death, fixed, and sectioned for light microscopy. Results from both eyes were substantially the same. The macular region was still drastically immature at 1 week. Even though a foveal depression existed, all cell layers were still present across it. Furthermore, the inner nuclear layer was divided into two separate layers. The receptor layer was reduced to one or two cells thick; receptors had both inner and outer segments, but they were very short and stumpy. The region of immaturity covered about 5° of the retina. These findings suggest that the central region of a human infant's retina is probably not fully functional at birth.
Tumor Suppression with a Combination of α-Difluoromethyl Ornithine and Interferon
Authors: Sunkara Prasad S. , Prakash Nellikunja J. , Mayer Gerald D. , Sjoerdsma Albert
Published: October 2006

α-Difluoromethyl ornithine and mouse type 1 interferon, when administered simultaneously, were highly toxic to B16 melanoma cells in culture. Oral administration of α-difluoromethyl ornithine suppressed B16 melanoma development in mice 85 percent whereas interferon given subcutaneously inhibited tumor growth only 24 percent. Total or near total suppression of tumor growth was observed in mice receiving both treatments.
HTLV-III in Cells Cultured from Semen of Two Patients with AIDS
Authors: Zagury D. , Bernard J. , Leibowitch J. , Safai B. , Groopman J. E. , Feldman M. , Sarngadharan M. G. , Gallo R. C.
Published: October 2006

Epidemiological results suggest that the etiological agent of the acquired immune deficiency syndrome (AIDS) is transmitted primarily through blood products, semen, and saliva. There is evidence that the human T-cell leukemia (lymphotropic) virus type III (HTLV-III) is this agent. HTLV-III has been isolated repeatedly from T cells obtained from peripheral blood or lymph node tissue of AIDS and pre-AIDS patients and of healthy people believed to have been exposed to the virus. In the present study, HTLV-III was detected in and isolated from T cells present in the seminal fluid of AIDS patients. Mononuclear cells from the semen of AIDS patients and normal individuals were cultured in the presence of T-cell growth factor (interleukin-2). After 6 to 8 days, HTLV-III antigens were transiently expressed by the cells from the AIDS patients but not by those from the normal individuals. When the mononuclear cells from the semen of AIDS patients were cocultured with a permissive human T-cell line, cell cultures were produced that expressed high levels of reverse transcriptase activity, showed retroviral particles by electron microscopy, and were positive for HTLV-III-specific antigens when tested by fixed-cell indirect immunofluorescence with the use of monoclonal antibodies to the p24 and p15 antigens of HTLV-III.
Multiple Sclerosis: Distribution of T Cell Subsets Within Active Chronic Lesions
Authors: Traugott Ute , Reinherz Ellis L. , Raine Cedric S.
Published: October 2006

The distribution of T cells and T cell subsets was examined within the human central nervous system in active lesions from seven patients with chronic multiple sclerosis. The monoclonal antibodies anti-T11, anti-T4, and anti-T8 were used to detect total (whole) T cells, helper T cells, and suppressor-cytotoxic T cells, respectively, and a monoclonal antibody against human Ia was used for macrophages and B cells. Lesion progression was associated with large numbers of T4
+
cells at the lesion margin and these extended great distances into the adjacent normal-appearing white matter. T8
+
cells were most commonly concentrated around the lesion margin and displayed a preferential perivascular distribution. Within the lesion center, only a few T cells were found. Ia
+
macrophages were most numerous within the centers of active lesions and were always present in the adjacent normal white matter. The monoclonal antibodies to T cells did not cross-react with glial cells including oligodendrocytes. These results indicate that T4
+
cells are actively involved in lesion extension and Ia
+
cells, in demyelination.
Pitch Memory: An Advantage for the Left-Handed
Authors: Deutsch Diana
Published: October 2006

In an auditory or musical memory task, subjects made pitch recognition judgments when the tones to be compared were separated by a sequence of interpolated tones. The left-handed subjects performed significantly better than the right-handed and also had a significantly higher variance. Further analysis showed that the superior performance was attributable largely to the left-handed subjects with mixed hand preference.
N
-Formylmethionyl Peptide Receptors on Equine Leukocytes Initiate Secretion But Not Chemotaxis
Authors: Snyderman Ralph , Pike Marilyn C.
Published: October 2006

The chemotaxis of leukocytes appears to be initiated by the binding of chemotactic factors to the surface of these cells.
N
-Formylated peptides induce chemotaxis and lysosomal enzyme secretion of leukocytes; because these peptides are available in a purified radiolabeled form, they have been useful in the characterization of receptors for chemotactic factors. Equine polymorphonuclear leukocytes secrete lysosomal enzymes but do not exhibit chemotaxis in response to the
N
-formylated peptides, even though they have a high-affinity cell surface receptor for these agents. The specificity of the equine receptor resembles the specificity of the receptor on chemotactically responsive leukocytes from other species. Equine polymorphonuclear leukocytes may thus be an excellent model for the study of the events that lead to a biological response following receptor occupancy.
DNA Synthesis in Cartilage Cells Is Stimulated by Oscillating Electric Fields
Authors: Rodan Gideon A. , Bourret Lizabeth A. , Norton Louis A.
Published: October 2006

External oscillating electric fields (1166 volts per centimeter, 5 hertz) enhanced the incorporation of [
3
H]thymidine into the DNA of chondrocytes isolated from the proliferative layer of embryonic (16 days) chick epiphysis. Verapamil or tetrodotoxin at 10
-6
M
concentrations completely blocked the electric field effect. Tetracaine reduced the incorporation of [
3
H]thymidine in both control and electrically stimulated cells. The findings support the hypothesis that Na
+
and Ca
2+
fluxes generated by the electrical perturbation trigger DNA synthesis in these cells.
Imipramine: Effect of Ovarian Steroids on Modifications in Serotonin Receptor Binding
Authors: Kendall David A. , Stancel George M. , Enna S. J.
Published: October 2006

Long-term administration of imipramine caused a decrease in serotonin
2
receptor binding in rat brain cerebral cortex, an effect that was abolished by ovariectomy. In contrast, ovariectomy had no effect on imipramine-induced decreases in hippocampal serotonin or in cerebral cortical and hippocampal β-adrenergic receptor binding. Administration of estradiol or progesterone separately or in combination reestablished the effect of imipramine treatment on cortical serotonin2 receptors. These results suggest that ovarian steroids may play an important, but subtle, role in the neurochemical and perhaps clinical response to this drug.
Mutation Caused by Human Phagocytes
Authors: Weitzman Sigmund A. , Stossel Thomas P.
Published: October 2006

Histidine-requiring mutants of
Salmonella typhimurium
TA100 were incubated with human peripheral blood leukocytes. More of these bacteria reverted to histidine independence than controls not incubated with cells. Phagocyte-rich suspensions were mutagenic, while heat-killed cells, lymphocytes, or mixed blood leukocytes of a patient with chronic granulomatous disease were not. Production of reactive oxygen metabolites could explain the capacity of phagocytes to induce mutation.
Regulation of Plasma Cholesterol by Lipoprotein Receptors
Authors: Brown Michael S. , Kovanen Petri T. , Goldstein Joseph L.
Published: October 2006

The lipoprotein transport system holds the key to understanding the mechanisms by which genes, diet, and hormones interact to regulate the plasma cholesterol level in man. Crucial components of this system are lipoprotein receptors in the liver and extrahepatic tissues that mediate the uptake and degradation of cholesterol-carrying lipoproteins. The number of lipoprotein receptors, and hence the efficiency of disposal of plasma cholesterol, can be increased by cholesterol-lowering drugs. Regulation of lipoprotein receptors can be exploited pharmacologically in the therapy of hypercholesterolemia and atherosclerosis in man.
Characterization of a 41-Residue Ovine Hypothalamic Peptide That Stimulates Secretion of Corticotropin and β-Endorphin
Authors: Vale Wylie , Spiess Joachim , Rivier Catherine , Rivier Jean
Published: October 2006

A peptide with high potency and intrinsic activity for stimulating the secretion of corticotropin-like and β-endorphin-like immunoactivities by cultured anterior pituitary cells has been purified from ovine hypothalamic extracts. The primary structure of this 41-residue corticotropin- and β-endorphin-releasing factor has been determined to be: H-Ser-Gln-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Thr-Lys-Ala-Asp-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn-Arg-Lys-Leu-Leu-Asp-Ile-Ala-NH
2
. The synthetic peptide is active in vitro and in vivo.
Renin and Angiotensin: the Complete System Within the Neuroblastoma × Glioma Cell
Authors: Fishman Mark C. , Zimmerman Earl A. , Slater Eve E.
Published: October 2006

Cells of the homogeneous hybrid line neuroblastoma × glioma (NG108-15) have many neuronal properties. Immunocytochemical tests show that they contain both immunoreactive renin and angiotensin; direct radioimmunoassays show that they are positive for renin, angiotensin I, and angiotensin II; enzymatic assays show that they contain angiotensinogen and converting enzyme as well. The renin appears to be present in an enzymatically inactive form that can be activated by trypsin and then blocked by antiserum to purified mouse submaxillary renin. Renin concentration and activity are increased by enhancing cellular differentiation with dibutyryl cyclic adenosine monophosphate or by serum withdrawal. These findings demonstrate a complete renin-angiotensin system within these neuron-like cells, and suggest that activation of intracellular renin could generate angiotensin II.
The Alu Family of Dispersed Repetitive Sequences
Authors: Schmid Carl W. , Jelinek Warren R.
Published: October 2006

A family of related sequences that includes approximately 500,000 members is the most prominent short dispersed repeat family in primate and rodent DNA's. The primate sequence is approximately 300 base pairs in length and is composed of two imperfectly repeated monomer units, whereas the rodent repeat consists of only a single monomer. Properties of this repeat sequence, its flanking sequences in chromosomal DNA, and RNA's transcribed from it suggest that it may be a mobile DNA element inserted at hundreds of thousands of different chromosomal locations.
Are Ions Involved in the Gating of Calcium Channels?
Authors: Saimi Yoshiro , Kung Ching
Published: October 2006

The rates of activation and deactivation of the currents carried by calcium, strontium, or barium ions through the voltage-sensitive calcium channel of
Paramecium
are different. The differences cannot be attributed to complications due to internal ion concentration, calcium channel inactivation, potassium current activation, surface charge effects, or incomplete space clamping. The findings indicate participation of the divalent cations in the voltage-driven calcium channel gating process.
Expression of a Cellular Oncogene During Liver Regeneration
Authors: Goyette Michele , Petropoulos Christos J. , Shank Peter R. , Fausto Nelson
Published: October 2006

The number of transcripts of the cellular oncogene
ras
, which is homologous to the transforming gene of Harvey sarcoma virus, increases during liver regeneration in rats. The increase in these transcripts in liver polysomal polyadenylated RNA occurs at the time of activation of DNA synthesis during the regenerative process induced by partial hepatectomy or carbon tetrachloride injury. The number of
ras
transcripts returns to basal levels within 72 hours. These observations show that transcription of a cellular oncogene increases in a regulated way in a nonneoplastic growth process.
Actions of Estrogens and Progestins on Nerve Cells
Authors: Pfaff Donald W. , McEwen Bruce S.
Published: October 2006

Estrogens and progestins alter electrical and chemical features of nerve cells, particularly in hypothalamus. Temporally, these events follow nuclear receptor occupation by these steroids, although not all effects have been proved to depend on translocation of receptors to the nucleus. Narrowing studies to focus on particular medial hypothalamic cells has been useful for understanding some of the actions of these steroids in brain. The variety of morphological, chemical, and electrical effects allow for a multiplicity in the cellular functions controlled by these hormones.
The Radicals in Cigarette Tar: Their Nature and Suggested Physiological Implications
Authors: Pryor William A. , Hales Brian J. , Premovic Pavle I. , Church Daniel F.
Published: October 2006

The paramagnetism of cigarette tar is found to be associated with at least four different types of species. One of the types is responsible for over 80 percent of the total paramagnetism and has a signal intensity that is independent of temperature from 60 to 250 K. This non-Curie-Weiss temperature dependence indicates that the principal paramagnetic species in tar is not an organic monoradical (doublet) species but instead is a donor-acceptor excimer with a paramagnetic excited state and a diamagnetic ground state. Modeling experiments suggest that the excimer consists of quinone (Q) and hydroquinone (QH
2
) molecules held in a tar matrix. Since such Q- QH
2
species are catalysts for the oxidation of hydrocarbons and are very active redox systems, this paramagnetic species may be implicated in the cocarcinogenic properties of tar. Alternatively, since semiquinone radicals are known to bind to DNA, the tar paramagnetic species may be directly involved in the carcinogenic properties of tar.
Calicivirus Isolation and Persistence in a Pygmy Chimpanzee (
Pan paniscus
)
Authors: Smith Alvin W. , Skilling Douglas E. , Ensley Philip K. , Benirschke Kurt , Lester Thomas L.
Published: October 2006

What may be the first calicivirus isolate from any primate species, including man, was recovered from a herpesvirus-like lip lesion on a pygmy chimpanzee and then, 6 months later, from the throat of the same animal. The infected individual and its cage mates had circulating antibodies that were type-specific for this calicivirus. The agent was antigenically different from 30 other calicivirus serotypes and is tentatively designated primate calicivirus Pan paniscus type 1 (PCV-Pan 1).
A Transforming
ras
Gene in Tumorigenic Guinea Pig Cell Lines Initiated by Diverse Chemical Carcinogens
Authors: Sukumar Saraswati , Pulciani Simonetta , Doniger Jay , DiPaolo Joseph A. , Evans Charles H. , Zbar Berton , Barbacid Mariano
Published: October 2006

Fetal guinea pig cells were transformed by treatment with four different chemical carcinogens including nitroso compounds and polycyclic hydrocarbons. As a consequence of this treatment, oncogenes capable of transforming NIH/3T3 cells became activated in each of five independently established clonal guinea pig cell lines. Molecular characterization of representative NIH/3T3 transformants revealed that the same oncogene was present in each of the cell lines tested. Moreover, detection of this transforming gene paralleled the acquisition of tumorigenic properties by these neoplastic cells.
Lines of T Lymphocytes Induce or Vaccinate Against Autoimmune Arthritis
Authors: Holoshitz Joseph , Naparstek Yaakov , Ben-Nun Avraham , Cohen Irun R.
Published: October 2006

The pathophysiology of autoimmune arthritis was studied by selecting and isolating lines of effector T lymphocytes from rats administered an arthritogenic dose of Mycobacterium tuberculosis in complete Freund's adjuvant to induce adjuvant arthritis. Irradiated rats were intravenously inoculated with a cell line characterized by proliferative reactivity to Mycobacterium tuberculosis and, to a lesser degree, to rat collagen type II. This produced arthritis in all the irradiated rats. Nonirradiated recipients failed to develop arthritis. However, such rats, and those recovering from cell-mediated arthritis, were resistant to subsequent attempts to induce adjuvant arthritis. Lines of T lymphocytes selected for responsiveness to other antigens had no effect. Therefore, a line of T lymphocytes responsive to bacteria or to collagen type II could either induce autoimmune arthritis or serve as an agent of vaccination against it.
Stable Nitrogen Isotope Ratios of Bone Collagen Reflect Marine and Terrestrial Components of Prehistoric Human Diet
Authors: Schoeninger Margaret J. , DeNiro Michael J. , Tauber Henrik
Published: October 2006

The δ
15
N values of bone collagen from Eskimos and from Northwest Coast Indians dependent on salmon fishing are about 10 per mil more positive than those from agriculturalists in historic times. Among prehistoric humans, two groups dependent on marine food sources show bone collagen δ
15
N values that are 4 to 6 per mil more positive than those from two agricultural groups. The nitrogen isotope ratios of bone collagen from prehistoric inhabitants of the Bahamas are anomalously low for reasons that relate to the biogeochemical cycle of nitrogen in coral reefs.
The Glycosylation of Hemoglobin: Relevance to Diabetes Mellitus
Authors: Bunn H. Franklin , Gabbay Kenneth H. , Gallop Paul M.
Published: October 2006

Glucose reacts nonenzymatically with the NH
2
-terminal amino acid of the β chain of human hemoglobin by way of a ketoamine linkage, resulting in the formation of hemoglobin A
Ic
. Other minor components appear to be adducts of glucose 6-phosphate and fructose 1,6-diphosphate. These hemoglobins are formed slowly and continuously throughout the 120-day life-span of the red cell. There is a two- to threefold increase in hemoglobin A
Ic
in the red cells of patients with diabetes mellitus. By providing an integrated measurement of blood glucose, hemoglobin A
Ic
is useful in assessing the degree of diabetic control. Furthermore, this hemoglobin is a useful model of nonenzymatic glycosylation of other proteins that may be involved in the long-term complications of the disease.
Size and Shape of the Lateral Intercellular Spaces in a Living Epithelium
Authors: Spring Kenneth R. , Hope Arvid
Published: October 2006

The lateral intercellular spaces of
Necturus
gallbladder epithelium were seen and measured while the living tissue was perfused in a new chamber. The compliance of the lateral cell membranes was calculated from the measured pressure-volume characteristics of the lateral intercellular spaces.
Biological Activity of Recombinant Human Interleukin-2 Produced in
Escherichia coli
Authors: Rosenberg Steven A. , Grimm Elizabeth A. , McGrogan Michael , Doyle Michael , Kawasaki Ernest , Koths Kirston , Mark David F.
Published: October 2006

The gene for interleukin-2 was isolated from the Jurkat cell line and from normal peripheral blood lymphocytes and, when inserted in
Escherichia coli
, was expressed at high concentrations. This interleukin-2 was purified to apparent homogeneity and tested for biological activity in a variety of assays in vitro and in vivo. The recombinant lymphokine supports the growth of murine and human interleukin-2 dependent cell lines, enhances the generation of murine and human cytolytic cells in vitro, and generates lymphokine activated killer cells from murine and human lymphocytes. It has a serum half-life of 2 to 3 minutes in the mouse and significantly enhances the generation of cytolytic cells in vivo after alloimmunization. No functional differences between native and the recombinant interleukin-2 molecules have been detected.
Normalization of Depressed Heart Function in Rats by Ribose
Authors: Zimmer H.-G.
Published: October 2006

Severe constriction of the abdominal aorta and simultaneous injection of isoproterenol in rats induced depression in heart function and reductions in cardiac adenosine triphosphate and total adenine nucleotides. When ribose was continuously infused for 24 hours, biosynthesis of cardiac adenine nucleotides was stimulated to such an extent that the reductions in adenosine triphosphate and total adenine nucleotides were prevented and left ventricular hemodynamic parameters were normal. These results support the hypothesis that adenosine triphosphate is primarily responsible for depression in myocardial contractility and that ribose is cardioprotective through its pronounced effects on adenine nucleotide metabolism in heart muscle.
Neuromagnetic Evidence of Spatially Distributed Sources Underlying Epileptiform Spikes in the Human Brain
Authors: Barth Daniel S. , Sutherling William , Engle Jerome , Beatty Jackson
Published: October 2006

Neuromagnetic measurements were performed on 17 subjects with focal seizure disorders. In all of the subjects, the interictal spike in the scalp electroencephalogram was associated with an orderly extracranial magnetic field pattern. In eight of these subjects, multiple current sources underlay the magnetic spike complex. The multiple sources within a given subject displayed a fixed chronological sequence of discharge, demonstrating a high degree of spatial and temporal organization within the interictal focus.
Inhibition of Human Estrogen Synthetase (Aromatase) by Flavones
Authors: Kellis James T. , Vickery Larry E.
Published: October 2006

Several naturally occurring and synthetic flavones were found to inhibit the aromatization of androstenedione and testosterone to estrogens catalyzed by human placental and ovarian microsomes. These flavones include (in order of decreasing potency) 7,8-benzoflavone, chrysin, apigenin, flavone, flavanone, and quercetin; 5,6-benzoflavone was not inhibitory. 7,8-Benzoflavone and chrysin were potent competitive inhibitors and induced spectral changes in the aromatase cytochrome P-450 indicative of substrate displacement. Flavones may thus compete with steroids in their interaction with certain monooxygenases and thereby alter steroid hormone metabolism.
Monoclonal Idiotope Vaccine Against
Streptococcus pneumoniae
Infection
Authors: McNamara Mary K. , Ward Ronald E. , Kohler Heinz
Published: October 2006

A monoclonal anti-idiotope antibody coupled to a carrier protein was used to immunize BALB/c mice against a lethal Streptococcus pneumoniae infection. Vaccinated mice developed a high titer of antibody to phosphorylcholine, which is known to protect against infection with Streptococcus pneumoniae. Measurement of the median lethal dose of the bacteria indicated that anti-idiotope immunization significantly increased the resistance of BALB/c mice to the bacterial challenge. Antibody to an idiotope can thus be used as an antigen substitute for the induction of protective immunity.