bluuebunny/crossref_metadata_2025 huggingface dataset:
Scintigraphy of Normal Mouse Ovaries with Monoclonal Antibodies to ZP-2, the Major Zona Pellucida Protein
Authors: East Iain J. , Keenan Andrew M. , Larson Steven M. , Dean Jurrien
Published: October 2006

The zona pellucida is an extracellular glycocalyx, made of three sulfated glycoproteins, that surrounds mammalian oocytes. Parenterally administered monoclonal antibodies specific for ZP-2, the most abundant zona protein, localize in the zona pellucida. When labeled with iodine-125, these monoclonal antibodies demonstrate a remarkably high target-to-nontarget tissue ratio and provide clear external radioimaging of ovarian tissue.
Activation of a c-K-
ras
Oncogene by Somatic Mutation in Mouse Lymphomas Induced by Gamma Radiation
Authors: Guerrero Isabel , Villasante Alfredo , Corces Victor , Pellicer Angel
Published: October 2006

Mouse tumors induced by gamma radiation are a useful model system for oncogenesis. DNA from such tumors contains an activated K-
ras
oncogene that can transform NIH 3T3 cells. This report describes the cloning of a fragment of the mouse K-
ras
oncogene containing the first exon from both a transformant in rat-2 cells and the brain of the same mouse that developed the tumor. Hybrid constructs containing one of the two pieces were made and only the plasmid including the first exon from the transformant gave rise to foci in NIH 3T3 cells. There was only a single base difference (G → A) in the exonic sequence, which changed glycine to aspartic acid in the transformant. By use of a synthetic oligonucleotide the presence of the mutation was demonstrated in the original tumor, ruling out modifications during DNA-mediated gene transfer and indicating that the alteration was present in the thymic lymphoma but absent from other nonmalignant tissue. The results are compatible with gamma radiation being a source of point mutations.
Autoimmunity and Increased c-
myb
Transcription
Authors: Mountz John D. , Steinberg Alfred D. , Klinman Dennis M. , Smith Howard R. , Mushinski J. Frederic
Published: October 2006

A single recessive gene,
1pr
, induces an autoimmune-lymphoproliferative syndrome in several strains of mice. The lymphoid organs of
1pr
/
1pr
mice contained cells with increased amounts of
myb
RNA, which codes for a protein found in the nucleus. A similar human lymphoproliferative disorder also had an increase in c-
myb
expression. Mouse T cells induced by mitogens to proliferate did not express large amounts of
myb
RNA, indicating that marked
myb
expression is not a general feature of lymphocyte activation and proliferation.
Prolonged Ca
2+
-Dependent Afterhyperpolarizations in Hippocampal Neurons of Aged Rats
Authors: Landfield Philip W. , Pitler Thomas A.
Published: October 2006

The possibility that calcium is elevated in brain neurons during aging was examined by quantifying afterhyperpolarizations induced by spike bursts in CA1 neurons of hippocampal slices from young and aged rats. The afterhyperpolarizations result from Ca
2+
-dependent K
+
conductance increases and are blocked in medium low in Ca
2+
and prolonged in medium high in Ca
2+
. The afterhyperpolarization and associated conductance increases were considerably prolonged in cells from aged rats, although inhibitory postsynaptic potentials did not differ with age. Since elevated intracellular Ca
2+
can exert deleterious effects on neurons, the data suggest that altered Ca
2+
homeostasis may play a significant role in normal brain aging.
Inability of Mouse Blastomere Nuclei Transferred to Enucleated Zygotes to Support Development in Vitro
Authors: McGrath James , Solter Davor
Published: October 2006

More than 90 percent of enucleated one-cell mouse embryos receiving pronuclei from other one-cell embryos successfully develop to the blastocyst stage in vitro. In this investigation, nuclei from successive preimplantation cleavage stages were introduced into enucleated one-cell embryos and the embryos were tested for development
in vitro
. Although two-cell nuclei supported development to the morula or blastocyst stage, four-cell, eight-cell, and inner cell mass cell nuclei did not. The inability of cell nuclei from these stages to support development reflects rapid loss of totipotency of the transferred nucleus and is not the result of simultaneous transfer of membrane or cytoplasm.
Phenylalanine Transfer RNA: Molecular Dynamics Simulation
Authors: Harvey Stephen C. , Prabhakaran M. , Mao Boryeu , McCammon J. Andrew
Published: October 2006

Yeast phenylalanine transfer RNA was subjected to a 12-picosecond molecular dynamics simulation. The principal features of the x-ray crystallographic analysis are reproduced, and the amplitudes of atomic displacements appear to be determined by the degree of exposure of the atoms. An analysis of the hydrogen bonds shows a correlation between the average length of a bond and the fluctuation in that length and reveals a rocking motion of bases in Watson-Crick guanine ⋅ cytosine base pairs. The in-plane motions of the bases are generally of larger amplitude than the out-of-plane motions, and there are correlations in the motions of adjacent bases.
Protein Engineering
Authors: Ulmer Kevin M.
Published: October 2006

The prospects for protein engineering, including the roles of x-ray crystallography, chemical synthesis of DNA, and computer modeling of protein structure and folding, are discussed. It is now possible to attempt to modify many different properties of proteins by combining information on crystal structure and protein chemistry with artificial gene synthesis. Such techniques offer the potential for altering protein structure and function in ways not possible by any other method.
High-Resolution Chromosome Sorting and DNA Spot-Blot Analysis Assign McArdle's Syndrome to Chromosome 11
Authors: Lebo Roger V. , Gorin Fredric , Fletterick Robert J. , Kao Fa-Ten , Cheung Mei-Chi , Bruce Barry D. , Kan Yuet Wai
Published: October 2006

A rapid gene-mapping system uses a high-resolution, dual-laser sorter to identify genes from separate human chromosomes prepared with a new stain combination. This system was used to sort 21 unique chromosome types onto nitrocellulose filter papers. Several labeled gene probes hybridized to the sorted chromosomal DNA types predicted by their previous chromosome assignments. The skeletal muscle glycogen phosphorylase gene was then mapped to a portion of chromosome 11 by spot blotting normal and translocated chromosomes.
Ovarian Secretion and Tumor Incidence
Authors: Murray William S.
Published: October 2006

(1) Non-breeding reduces tumor incidence in mice and delays the time of tumor appearance (207 mice used).

(2) Two hundred and ten female mice castrated at 28-35 days behave much the same as non-breeding females.

(3) Two hundred and forty-one males castrated at 28-35 days did not develop tumor, thus resembling non-castrated males.

(4) Spontaneous tumors, never obtained in thousands of normal males of the stock used, may develop in castrated males which have received subcutaneous transplants of ovarian tissue (210 operated—four tumors).
Structure of a Mouse Submaxillary Messenger RNA Encoding Epidermal Growth Factor and Seven Related Proteins
Authors: Scott James , Urdea Mickey , Quiroga Margarita , Sanchez-Pescador Ray , Fong Noel , Selby Mark , Rutter William J. , Bell Graeme I.
Published: October 2006

The structure of the messenger RNA (mRNA) encoding the precursor to mouse submaxillary epidermal growth factor (EGF) was determined from the sequence of a set of overlapping complementary DNA's (cDNA). The mRNA is unexpectedly large, about 4750 nucleotide bases, and predicts the sequence of preproEGF, a protein of 1217 amino acids (133,000 molecular weight). The EGF moiety (53 amino acids) is flanked by polypeptide segments of 976 and 188 amino acids at its amino and carboyxl termini, respectively. The amino terminal segment of the precursor contains seven peptides with sequences that are similar but not identical to EGF.
The Latency of Pathways Containing the Site of Motor Learning in the Monkey Vestibulo-Ocular Reflex
Authors: Lisberger S. G.
Published: October 2006

The vestibulo-ocular reflex helps to stabilize retinal images by generating smooth eye movements that are equal to and opposite each rotatory head movement. It is well known that the reflex undergoes adaptive plasticity or "motor learning" whenever there is persistent image motion during head turns: the resulting changes in the reflex occur gradually and help to restore image stability. A new approach makes it possible to identify the pathways containing the site of motor learning according to their total latency in response to natural vestibular stimuli. The fastest pathways required 14 milliseconds to initiate a vestibulo-ocular reflex, but the site of motor learning was in pathways having latencies of at least 19 milliseconds.
Human Endothelial Cells: Use of Heparin in Cloning and Long-Term Serial Cultivation
Authors: Thornton Susan C. , Mueller Stephen N. , Levine Elliot M.
Published: October 2006

Endothelial cells from human blood vessels were cultured in vitro, with doubling times of 17 to 21 hours for 42 to 79 population doublings. Cloned human endothelial cell strains were established for the first time and had similar proliferative capacities. This vigorous cell growth was achieved by addition of heparin to culture medium containing reduced concentrations of endothelial cell growth factor. The routine cloning and long-term culture of human endothelial cells will facilitate studying the human endothelium in vitro.
Coping and the Stress-Induced Potentiation of Stimulant Stereotypy in the Rat
Authors: MacLennan A. John , Maier Steven F.
Published: October 2006

It has been shown that stressed rats display increased stereotypy in response to a subsequent amphetamine challenge. Evidence is presented showing that stress potentiates cocaine stereotypy as well. These effects of stress were found to be particular to stress that could not be controlled in that rats receiving an identical amount of stress from footshock, but allowed to control its duration, displayed no more stereotypy than did nonstressed rats. These findings have implications for the role of stress and coping in amphetamine and cocaine psychoses, endogenous psychoses, and some forms of schizophrenia.
Food Safety: Revising the Statute
Authors: Kessler David A.
Published: October 2006

There is increasing recognition that federal food safety laws and policies need to be revised. Congressional debate on proposed amendments to the Food, Drug, and Cosmetic Act has generated several different perspectives on how the food safety laws should be changed. Before a consensus can be reached, scientists, regulators, the food industry, and consumers will have to review such complex and controversial issues as the level of acceptable risk, the value of risk-benefit analysis, the proper role of independent scientific review, and the reliability of quantitative risk assessment.
The Ultraviolet Receptor if Bird Retinas
Authors: Chen De-Mao , Collins James S. , Goldsmith Timothy H.
Published: October 2006

The eyes of 15 species of birds from 10 families have some cones maximally sensitive at 370 nanometers in the near-ultraviolet. Spectral sensitivity was measured by recording extracellularly in opened eyecups, and a maximum in the ultraviolet was revealed by selectively adapting the retina with yellow background lights. The 370-nanometer spectral sensitivity function is attributed to receptors because its spectral position does not vary with the strength of adaptation and because it is present when the receptor potentials are isolated from the contributions of higher order retinal neurons by exposing the retina to sodium aspartate. These measurements demonstrate the basis for the ultraviolet sensitivity of birds that has been seen in behavioral experiments, and they provide further evidence that many vertebrates share with insects vision in the near-ultraviolet.
Endogenous Ionic Currents Traverse Intact and Damaged Bone
Authors: Borgens Richard B.
Published: October 2006

Living bone drives an electric current through itself and into sites of damage. Such "fracture currents" consist of two components: an intense, decaying current dependent on bone deformation and a stable, persistent current driven by a cellular battery. The latter is carried by chloride ions and, to a lesser extent, by sodium, magnesium, and calcium ions. Endogenous fracture currents are of the same polarity and similar magnitude as clinically applied currents that are successful in treating chronic nonunions in fractured bones. This suggests that the defect in biological nonunions may reside in the electrophysiology of repair.
Hybrid Dysgenesis in
Drosophila melanogaster
Authors: Bregliano J. C.. , Picard G.. , Bucheton A.. , Pelisson A.. , Lavige J. M.. , L'Heritier P..
Published: October 2006

Several dysgenic traits may occur within the
Drosophila melanogaster
species as a result of crosses between different strains. Crossing two mutually interacting categories, named inducer and reactive, may lead, among other abnormalities, to a specific kind of female sterility that has proved useful for investigating the genetic factors involved in the interaction. The reactive state appears to result from a cytoplasmic state ultimately controlled by a chromosomal polygenic system. The inducer character is determined by a chromosomal factor that exhibits all characteristics of a transposable element. Overall, the data contribute to clarification of mutator activities in
D. melanogaster
and open new opportunities to investigate unusual genetic mechanisms.
Endocytotic Sucrose Uptake in
Amoeba proteus
Induced with the Calcium Ionophore A23187
Authors: Prusch Robert D.
Published: October 2006

The calcium ionophore A2187 brings about an influx of calcium and uptake of sucrose by endocytosis in
Amoeba proteus
. The amount of endocytotic sucrose uptake elicited by the ionophore depends upon the external calcium ion concentration. Calcium ion movements may serve to couple the surface phase of endocytosis with cytoplasmic uptake of the endocytotic inducer.
Carbon Dioxide Sensitivity of Mosquitoes Infected with California Encephalitis Virus
Authors: Turell Michael J. , Hardy James L.
Published: October 2006

Four species of mosquitoes became sensitive to carbon dioxide approximately 3 to 4 days after they received intrathoracic injections of California encephalitis virus.
Aedes melanimon
and
Aedes dorsalis
infected orally with California encephalitis virus also became carbon dioxide-sensitive, but mosquitoes infected transovarially did not. Sensitivity to carbon dioxide was inhibited by antiserum to California encephalitis virus. To our knowledge this is the first report of carbon dioxide sensitivity induced in arthropods by a bunyavirus and the first demonstration of this phenomenon by an arbovirus in its proven vector.
Cognitive Interaction After Staged Callosal Section: Evidence for Transfer of Semantic Activation
Authors: Sidtis John J. , Volpe Bruce T. , Holtzman Jeffrey D. , Wilson Donald H. , Gazzaniga Michael S.
Published: October 2006

Sensory and cognitive functions were assessed in a right-handed male before and after partial and complete callosal commissurotomy. After the initial posterior section was made, there was no evidence of interhemispheric sensory transfer, although the left hemisphere did have access to stimulus-related semantic and episodic information from the right hemisphere. After the callosum was completely sectioned, this exchange was no longer observed.
Excitation of
Limulus
Photoreceptors by Vanadate and by a Hydrolysis-Resistant Analog of Guanosine Triphosphate
Authors: Fein Alan , Corson D. Wesley
Published: October 2006

Discrete voltage fluctuations that occur spontaneously or in response to dim lights can be recorded from the ventral photoreceptors of
Limulus
. The injection of vanadate or the hydrolysis-resistant analog of guanosine triphosphate, GTP-γ-S, into ventral photoreceptors induces the production of discrete waves in the dark. The chemically induced discrete waves are similar to those induced by light. Ventral photoreceptors may contain a guanyl nucleotide binding protein whose activation by vanadate or GTP-γ-S induces the discrete waves.
The Cell Sap of
Valonia
and
Halicystis
Authors: Cooper W. C. , Blinks L. R.
Published: October 2006

Comparison is made between the saps of
Valonia ventricosa
of Florida and the Bermuda
Halicystis
, formerly known as
V. ventricosa
. An even higher percentage of potassium is found in
V. ventricosa
than in
V. macrophysa
, while
Halicystis
has been shown to have very little.
Somatic Mutation in Genes for the Variable Portion of the Immunoglobulin Heavy Chain
Authors: Sims John , Rabbitts Terence H. , Estess Pila , Slaughter Clive , Tucker Philip W. , Capra J. Donald
Published: October 2006

The size of the gene pool potentially encoding antibodies to
p
-azophenyl arsonate has been examined. A heavy chain-specific full-length complementary DNA clone has been constructed with the use of messenger RNA from a hybridoma that produces antibodies to the arsonate hapten and bears nearly a full complement of the determinants comprising the cross-reactive idiotype (CRI). The sequences of both the complementary DNA clone and the corresponding immunoglobulin heavy chain have been independently determined. A probe for the variable region gene was prepared from the original heavy chain complementary DNA clone and used to analyze, by Southern filter hybridization, genomic DNA from both A/J (CRI positive) and BALB/c (CRI negative) mice. Approximately 20 to 25 restriction fragments containing "germline" variable region gene segments were detected in both strains, and many are shared by both, Since 35 CRI-positive heavy chains have been partially sequenced thus far and 31 are different, the results of the hybridization analysis suggest that somatic mutation events involving the variable region gene segments of the heavy chain play a role in the origin of the amino acid sequence diversity seen in this system.
Measurement of Intracellular Free Calcium in Monkey Kidney Cells with Aequorin
Authors: Borle A. B. , Snowdowne K. W.
Published: October 2006

A method has been developed for the measurement of intracellular free calcium in mammalian cells. The calcium-sensitive photoprotein aequorin can be incorporated into isolated cells by hypo-osmotic treatment without altering the cell viability, permeability, or metabolism. Intracellular calcium activity (Ca
1
2+
) was monitored in a perfusion system. In monkey kidney cells (LLC-MK
2
), Ca
1
2+
is approximately 57 nanomoles per liter. Changes in Ca
1
2+
with time can also be followed: exposure of the cells to anaerobiosis or the calcium ionophore A23187 reversibly increases Ca
1
2+
. The method has also been successfully tested in rat hepatocytes.
Development of the Place Principle: Acoustic Trauma
Authors: Rubel Edwin W. , Ryals Brenda M.
Published: October 2006

Developmental changes in the site of receptor damage following pure-tone acoustic overstimulation were examined in the basilar papillae of embryonic and hatchling chickens. During development, a systematic shift in the position of damage toward the apex of the cochlea was produced by each of three frequencies, suggesting that the transduction properties of the sensory epithelium systematically shift with age. These results imply that neurons in the central nervous system may be maximally stimulated by different sounds during development.
Attogram Detection Limit for Aqueous Dye Samples by Laser-Induced Fluorescence
Authors: Dovichi Norman J. , Martin John C. , Jett James H. , Keller Richard A.
Published: October 2006

A modified flow cytometer has been used to detect attogram quantities of aqueous rhodamine 6G by laser-induced fluorescence analysis. A detection limit of 28 attograms (35,000 molecules) was obtained, nearly two orders of magnitude better than earlier measurements. The detection limit in concentration units was 1.4 × 10
-13
mole per liter. During the 1-second measurement period, the total volume sampled was 0.42 microliter. On average, only half a rhodamine 6G molecule was present in the 6-picoliter probed volume.
Schizophrenia: A Neurophysiological Evaluation of Abnormal Information Processing
Authors: Baribeau-Braun Jacinthe , Picton Terence W. , Gosselin Jean-Yves
Published: October 2006

Evoked potential indices of an early and late stage of attentional processing were recorded from schizophrenic and normal subjects during dichotic listening tasks. Despite slow and inaccurate detections, the schizophrenic subjects were able to focus selectively to different ears but only at a fast stimulation rate, showing integrity of the early selective stage. They showed an abnormal late stage, indicating inefficiency in processing information from detected targets. Marked deficits at a slow stimulation rate and during divided attention suggest that the schizophrenic attention disorder is one of control and maintenance of a selective processing strategy rather than of general slowness or absence of selectivity.
Free-Running Activity Rhythms in the Rat: Entrainment by Melatonin
Authors: Redman Jenny , Armstrong Stuart , Ng Kim T.
Published: October 2006

The pineal gland hormone melatonin may play a role in synchronization of rat circadian rhythms. Free-running activity rhythms of the rat were entrained by a daily melatonin injection, with entrainment occurring when the onset of activity coincided with the time of daily injections. When injections were stopped, activity rhythms became free-running again. Thus in pharmacological experiments, the time of day of melatonin administration is crucial.
Local Differences in the Amount of Early Cell Death in Neocortex Predict Adult Local Specializations
Authors: Finlay Barbara L. , Slattery Michael
Published: October 2006

The amount of early cell loss in five neocortical areas was inversely related to adult numbers of neurons in those areas. Differential cell death predicted particularly the thickness of the upper cortical laminae; it was not related to neuron numbers in the lower laminae. Cell loss thus determines some features of local neocortical differentiation.
Tension Transients in Single Isolated Smooth Muscle Cells
Authors: Warshaw David M. , Fay Fredric S.
Published: October 2006

Tension transients were recorded in a single smooth muscle cell. The transient contains a linear elastic response and a biphasic recovery that appear to originate from the cross-bridges. A comparison of transients in smooth and fast skeletal muscle fibers suggests that the cross-bridge in smooth muscle is more compliant than the cross-bridge in striated muscle and that transitions between several cross-bridge states occur more slowly in smooth muscle than in striated muscle.
Cell Growth on Liquid Microcarriers
Authors: Keese Charles R. , Giaever Ivar
Published: October 2006

Anchorage-dependent cell growth is demonstrated on microcarriers of fluorocarbon fluid formed by emulsification and stabilized with polylysine.
Proglumide: Selective Antagonism of Excitatory Effects of Cholecystokinin in Central Nervous System
Authors: Chiodo Louis A. , Bunney Benjamin S.
Published: October 2006

Extracellular single-unit recording techniques were used to test the ability of proglumide to block cholecystokinin-induced excitation of rat midbrain dopaminergic neurons and dopamine-sensitive prefrontal cortex cells. Intravenous and iontophoretic proglumide administration consistently blocked cholecystokinin-induced excitations while having no effect on glutamic acid-induced increases in activity. This selective blockade of central cholecystokinin effects by proglumide suggests that this drug may be valuable for studying the possible role of cholecystokinin as a neurotransmitter or neuromodulator in the central nervous system.
Alcohol-Induced Spasms of Cerebral Blood Vessels: Relation to Cerebrovascular Accidents and Sudden Death
Authors: Altura Burton M. , Altura Bella T. , Gebrewold Asefa
Published: October 2006

Ethyl alcohol produced graded contractile responses in rat cerebral arterioles and venules in vivo and in isolated canine basilar and middle cerebral arteries at a concentration range (10 to 500 milligrams per deciliter) which parallels that needed for its graded effects of euphoria, mental haziness, muscular incoordination, stupor, and coma in humans. Two specific calcium antagonists, nimodipine and verapamil, prevented or reversed the alcohol-induced cerebrovasospasm and thus may prove valuable in treating the hypertension and stroke observed in heavy users of alcohol.
Uphill Sodium Transport Driven by an Inward Calcium Gradient in Heart Muscle
Authors: Bridge John H. B. , Bassingthwaighte James B.
Published: October 2006

Heart cells were loaded with sodium by treatment with toxic doses of acetyl strophanthidin. After this treatment, an increase in extracellular calcium resulted in a transient net outward sodium flux against its electrochemical gradient and in net cellular uptake of calcium. It is concluded that the free energy for the net outward sodium movement was derived from the increased calcium gradient and that these ion movements took place through the sodium-calcium exchange. While in the normal physiological state the sodium-calcium exchange produces calcium extrusion from the cell, these experiments demonstrate its reversibility.
Regenerative Impulses in Taste Cells
Authors: Roper S.
Published: October 2006

Taste cells and nongustatory epithelial cells in the isolated lingual mucosa from the mud puppy
Necturus maculosus
were impaled with microelectrodes. The taste cells, but not surrounding epithelial cells, were electrically excitable when directly stimulated with current passed through the recording electrode. Action potentials produced by taste cells had both a sodium and a calcium component.
Cortical Dopaminergic Involvement in Cocaine Reinforcement
Authors: Goeders Nick E. , Smith James E.
Published: October 2006

Neuronal systems involved in the initiation of cocaine reinforcement were investigated by identifying brain sites where direct application of the drug was reinforcing. This was accomplished by allowing rats to self-administer picomolar concentrations of cocaine into discrete brain regions. The medial prefrontal cortex supported self-administration, while the nucleus accumbens and ventral tegmental area did not. Self-administration could be attenuated by including equimolar concentrations of the dopaminergic D
2
-receptor antagonist sulpiride in the microinjection system. These results imply that cocaine reinforcement is mediated in part through a direct action on mesocortical dopaminergic receptors.
Otosclerotic Lesions in the Inbred LP/J Mouse
Authors: Chole Richard A. , Henry Kenneth R.
Published: October 2006

Inbred LP/J mice develop abnormal bony lesions that are grossly and histologically similar to the lesions of human otosclerosis. This is the first known occurrence of spontaneous otosclerosis-like lesions in an animal. As in the human disease, these lesions impair audition by immobilizing the ossicles of the middle ear. The LP/J mouse may be an animal model for this common human disease.
Hepatocarcinogenicity of Glandless Cottonseeds and Cottonseed Oil to Rainbow Trout (
Salmo gairdnerii
)
Authors: Hendricks J. D. , Sinnhuber R. O. , Loveland P. M. , Pawlowski N. E. , Nixon J. E.
Published: October 2006

Glandless cottonseed kernels are available for purchase and consumption by the general public. These kernels contain no gossypol but still have a full complement of naturally occurring cyclopropenoid fatty acids, which in rainbow trout are active as synergists with aflatoxins and primary liver carcinogens. Diets containing glandless cottonseed kernels or a lightly processed cottonseed oil produced significant numbers of hepatocellular carcinomas in rainbow trout after 1 year. The much greater incidence of cancer induced by the kernel than by the oil indicates that synergists or other carcinogens may be present in the kernel in addition to the cyclopropenoid fatty acids.
Cognition and Long-Term Use of Ganja (Cannabis)
Authors: Schaeffer Jeffrey , Andrysiak Therese , Ungerleider J. Thomas
Published: October 2006

Neuropsychological variables and urine cannabinoid metabolites were evaluated in ten subjects born, raised, and educated in the United States and having histories of heavy or prolonged use of cannabis. No impairment of cognitive function was found. Cannabinoid metabolites in excess of 50 nanograms per milliliter were present in the ten urine samples. The tetrahydrocannabinol content of cannabis exceeded 8.0 percent.
Insulin Receptors: Differences in Structural Organization on Adipocyte and Liver Plasma Membranes
Authors: Jarett Leonard , Schweitzer John B. , Smith Robert M.
Published: October 2006

Comparison was made of the distribution of the insulin receptor sites on adipocyte and liver plasma membranes by using ferritin-insulin. Two-thirds of the occupied insulin receptors on adipocytes occurred in groups of two or more whereas up to two-thirds of the receptors on liver occurred as single receptors. Ferritin-insulin did not cause aggregation of the receptor sites in either tissue. The naturally occurring groups of receptors on adipocyte membranes may play a role in the greater sensitivity of adipocytes to insulin.
Cadmium-113 Nuclear Magnetic Resonance Studies of Bovine Insulin: Two-Zinc Insulin Hexamer Specifically Binds Calcium
Authors: Sudmeier J. L. , Bell S. J. , Storm M. C. , Dunn M. F.
Published: October 2006

By use of cadmium-113 nuclear magnetic resonance spectroscopy, a specific calcium ion binding site has been identified in the bovine two-zinc insulin hexamer. This site is composed of six glutamyl carboxylate groups clustered in the center of the hexamer, and is distinct from the normal zinc ion binding sites.
Serum from Monkeys with Histories of Fetal Wastage Causes Abnormalities in Cultured Rat Embryos
Authors: Klein Norman W. , Plenefisch John D. , Carey Sean W. , Fredrickson W. Timm , Sackett Gene P. , Burbacher Thomas M. , Parker Robert M.
Published: October 2006

Rat embryos in the mid-head-fold stage were cultured on female monkey serum for 48 hours. On the basis of embryo response, the investigators, with no knowledge of the donors' reproductive histories, correctly identified the serum from two high-risk breeders among 18 rhesus monkeys and the serum from 12 of 14 high-risk breeders among 26 pig-tailed monkeys as teratogenic. Of the embryo response parameters examined, abnormality type and frequency were more closely correlated with donor reproductive histories than embryo protein content or somite number.
Role of Vitamin B
12
in Methyl Transfer for Methane Biosynthesis by
Methanosarcina barkeri
Authors: Wood J. M. , Moura Isabel , Moura J. J. G. , Santos M. H. , Xavier A. V. , LeGall J. , Scandellari M.
Published: October 2006

When
Methanosarcina barkeri
is grown on methanol as the sole carbon source, a B
12
-containing protein is synthesized by this organism. This B
12
protein contains bound aquocobalamin, and when this cofactor is reduced and methylated with [
14
C]methyl iodide, the resultant [
14
C]methyl B
12
protein is extremely active in the biosynthesis of
14
C-labeled methane. These findings indicate that a B
12
-dependent system is operative in the biological formation of methane in addition to other systems that are B
12
-independent.
Prenatal and Neonatal Exposure to Cimetidine Results in Gonadal and Sexual Dysfunction in Adult Males
Authors: Anand S. , Van Thiel D. H.
Published: October 2006

Exposure of rats to cimetidine during intrauterine life and the immediate neonatal period results in hypoandrogenization in adult life with decreased weights of androgen-dependent tissues and decreased concentrations of testosterone. Moreover, sexual behavior patterns in adult life are disturbed as shown by a lack of sexual motivation and decreased performance.
Artificial Enzymes
Authors: Breslow Ronald
Published: October 2006

Simple chemical catalysts have been designed to achieve some desirable features of enzymes. These novel catalysts are not proteins, but they may incorporate the typical enzyme catalytic groups and they achieve selectivity in their reactions by use of geometric control, as do enzymes. Catalysts that carry out geometrically controlled chlorinations of aromatic rings and steroids have been constructed. Other catalysts achieve the selective synthesis of amino acids, and still others imitate ribonuclease in detailed mechanism and hydrolyze RNA. Optimization of geometries has led to a rate acceleration of over 10
8
in one instance.
Tetrodotoxin Blocks the Formation of Ocular Dominance Columns in Goldfish
Authors: Meyer Ronald L.
Published: October 2006

Optic fibers from both eyes were made to regenerate simultaneously into one tectum in goldfish. Autoradiography at various times later revealed that regenerating left and right fibers overlapped extensively for up to 4 weeks and subsequently segregated into eye dominance columns by 8 weeks. Continuous tetrodotoxin treatment of both eyes prevented the formation of columns for up to 13 weeks and was equally effective if begun at 6 weeks. When tetrodotoxin treatment was stopped after 11 weeks, columns subsequently formed in the next 3 weeks. Blockade of only one eye did not prevent column formation at 8 weeks.
Color Vision Is Altered During the Suppression Phase of Binocular Rivalry
Authors: Smith Earl L. , Levi Dennis M. , Harwerth Ronald S. , White Janis M.
Published: October 2006

Increment-threshold spectral sensitivity functions were determined during the dominance and suppression phases of binocular rivalry. The shapes of the functions obtained during the dominance phase exhibited three maxima at approximately 440, 530, and 610 nanometers and resembled functions obtained for nonrivalrous control conditions. However, the functions measured during suppression had a single broad peak near 555 nanometers and were adequately described by functions measured with flicker methods during nonrivalrous conditions. The results indicate that binocular rivalry differentially attenuates opponent-color information relative to achromatic information.
Mouse c-myc Oncogene Is Located on Chromosome 15 and Translocated to Chromosome 12 in Plasmacytomas
Authors: Crews Stephen , Barth Richard , Hood Leroy , Prehn John , Calame Kathryn
Published: October 2006

Hybridization studies with viral oncogene probes indicate that c-myc, the cellular gene homologous to the transforming gene of avian myelocytomatosis virus, resides on mouse chromosome 15 and in many plasmacytomas is translocated to the antibody heavy chain gene locus on chromosome 12. The transcriptional orientation of the translocated c-myc sequence is opposite the orientation of the adjacent C
α
gene that codes for the heavy chain of immunoglobulin A. The translocated c-myc sequence is not the same oncogene detected in murine plasmacytomas by the NIH-3T3 cell transformation assay.
Dual Task Interactions Due Exclusively to Limits in Processing Resources
Authors: Holtzman Jeffrey D. , Gazzaniga Michael S.
Published: October 2006

Information presented to each hemisphere of the commissurotomy patient is available only to the stimulated hemisphere. Despite this, the hemispheres have access to a common pool of processing resources, which, under conditions of demanding bilateral stimulation, is distributed between the hemispheres.
S
-Adenosylhomocysteine Hydrolase Is an Adenosine-Binding Protein: a Target for Adenosine Toxicity
Authors: Hershfield Michael S. , Krodich Nicholas M.
Published: October 2006

When adenosine deaminase activity is inhibited, low concentrations of adenosine are toxic to human lymphoblast mutants that are unable to convert adenosine to intracellular nucleotides. In order to identify the mediator of this cytotoxicity, we searched for a cytoplasmic protein capable of binding adenosine with high affinity. Such a protein was identified in extracts of human lymphoblasts and placenta as the enzyme
S
-adenosylhomocysteine hydrolase.
Fractional Factorial Analysis of Growth and Weaning Success in
Peromyscus maniculatus
Authors: Porter W. P. , Busch R. L.
Published: October 2006

Fractional factorial designs were used to explore simultaneously the effects of eight variables on survival and growth of neonatal deer mice,
Peromyscus maniculatus
. Two of the variables had significant effects on weaning success. The magnitudes of their effects are illustrated.
Familial Studies of Intelligence: A Review
Authors: Bouchard Thomas J. , McGue Matthew
Published: October 2006

A summary of 111 studies identified in a survey of the world literature on familial resemblances in measured intelligence reveals a profile of average correlations consistent with a polygenic mode of inheritance. There is, however, a marked degree of heterogeneity of the correlations within familial groupings, which is not moderated by sex of familial pairing or by type of intelligence test used.
Naloxone Reverses Neonatal Depression Caused by Fetal Asphyxia
Authors: Chernick Victor , Craig Randy J.
Published: October 2006

Pregnant near-term rabbits were given an intravenous dose of saline or the opiate antagonist naloxone and then asphyxiated. The fetuses were delivered by cesarean section and evaluated for respiration, color, muscle tone, response to stimulation, and general activity at 1, 3, 5, 10, 15, and 30 minutes of age. The naloxone-treated pups had significantly better scores during the first 15 minutes after birth than the saline-treated pups. Naloxone did not adversely affect the scores of nonasphyxiated pups. These data suggest that endogenous opiates worsen the neonatal depression caused by intrauterine asphyxia and that this effect can be reversed by naloxone.
A Monosialoganglioside Is a Monoclonal Antibody-Defined Antigen of Colon Carcinoma
Authors: Magnani John L. , Brockhaus Manfred , Smith David F. , Ginsburg Victor , Blaszczyk Magdalena , Mitchell Kenneth F. , Steplewski Zenon , Koprowski Hilary
Published: October 2006

The antigen of a monoclonal antibody that is specific for cells of human carcinoma of the colon is a monosialoganglioside as determined by the direct binding of antibody to thin-layer chromatograms of total lipid extracts of tissues. Binding of antibody to chromatograms is detected by autoradiography after the application of iodine-125-labeled F(ab′)
2
of rabbit immunoglobulin G antibodies to mouse immunoglobulins.
Maternal Hyperoxia Greatly Reduces the Incidence of Phenytoin-Induced Cleft Lip and Palate in A/J Mice
Authors: Millicovsky Guillermo , Johnston Malcolm C.
Published: October 2006

The A/J mouse has been used to study the teratogenic effects of phenytoin. The developmental abnormalities produced in offspring of this model are similar to some of the malformations observed in cases of human "fetal hydantoin syndrome." Placing pregnant A/J mice in a hyperoxic chamber after phenytoin injection greatly reduces the incidence of phenytoin-induced cleft lip and palate. These results suggest that phenytoin may affect embryonic development indirectly by altering maternal physiology. This maternally mediated mechanism, and the protection against it afforded by hyperoxia, has general implications for the effects of maternal toxicity on teratogenesis.
Photoperiodic Control and Effects of Melatonin on Nonshivering Thermogenesis and Brown Adipose Tissue
Authors: Heldmaier Gerhard , Steinlechner Stephan , Rafael Johannes , Vsiansky Pavel
Published: October 2006

Exposure to a short photoperiod improved the thermogenic capacity, and cold resistance of Djungarian hamsters and increased the respiratory power of their brown adipose tissue. Exposure to a long photoperiod caused a decrease in thermogenic measurements. This thermotropic action of the short photoperiod was detectable only during late summer and fall. A similar thermotropic response could be elicited by implanting hamsters with melatonin, indicating that the pineal may be involved in photoperiodic control of thermoregulatory effectors.
Optical Recording of Calcium Action Potentials from Growth Cones of Cultured Neurons with a Laser Microbeam
Authors: Grinvald Amiram , Farber Ira C.
Published: October 2006

Simultaneous recordings of calcium action potentials directly from growth cones and from somata of neuroblastoma cells indicated that they could be generated in the neurites at or near growth cones. Growth cone responses were measured with a fluorescent voltage-sensitive dye and a 5-milliwatt helium-neon laser microbeam as a monitoring light source.
Medical Therapies for Mood Disorders Alter the Blood-Brain Barrier
Authors: Preskorn Sheldon H. , Irwin George H. , Simpson Steven , Friesen Douglas , Rinne James , Jerkovich George
Published: October 2006

The effects of amitriptyline, lithium, and electroconvulsive shock on cerebral permeability and blood flow were tested. These three treatments share in common (i) the ability to influence the functional activity of central adrenergic neurons by way of effects on the release, reuptake, or metabolism of norepinephrine and (ii) therapeutic efficacy in mood disturbances. Under control conditions, cerebral permeability increases linearly with increasing arterial partial pressure of carbon dioxide and hence cerebral blood flow. All three treatments altered this relationship in a manner consistent with their adrenergic effects. Amitriptyline potentiated this increase in cerebral permeability whereas lithium and electroconvulsive shock blunted this phenomenon. These results support the hypothesis that one function of central adrenergic neurons is regulation of the blood-brain barrier and raise the possibility that a related effect may underlie the clinical usefulness of such treatments.
Electrical Potentials in Human Brain During Cognition: New Method Reveals Dynamic Patterns of Correlation
Authors: Gevins Alan S. , Doyle Joseph C. , Cutillo Brian A. , Schaffer Robert E. , Tannehill Robert S. , Ghannam Jess H. , Gilcrease Virginia A. , Yeager Charles L.
Published: October 2006

A new technique has been developed for identifying, in humans, dynamic spatiotemporal electrical patterns of the brain during purposive behaviors. In this method, single-trial time-series correlations between brain macropotentials recorded from different scalp sites are analyzed by distribution-independent mathematical pattern recognition. Dynamic patterns of correlation clearly distinguished two brief visuomotor tasks differing only in type of mental judgment required (spatial or numeric). These complex patterns shifted in the anterior-posterior and left-right axes between successive 175-millisecond intervals, indicating that many areas in both cerebral hemispheres were involved even in these simple judgments. These patterns were not obtainable by conventional analysis of averaged evoked potentials or by linear analysis of correlations, suggesting that the new technique will advance the study of human brain activity related to cognition and goal-directed behaviors.
Affective Behavior in Patients with Localized Cortical Excisions: Role of Lesion Site and Side
Authors: Kolb Bryan , Taylor Laughlin
Published: October 2006

The perception of emotion in verbal and facial expression, and the spontaneous production of conversational speech were studied in patients with unilateral focal excisions of frontal, temporal, or parieto-occipital cortex. Lesions of the left hemisphere impaired the matching of verbal descriptions to appropriate verbal categories of emotional states, whereas with lesions of the right hemisphere, the matching of different faces displaying similar emotional states was impaired. The effects of lesions of both left and right hemisphere occurred regardless of the locus of the lesion. On the other hand, frontal-lobe lesions had differential effects upon unsolicited talking; lesions of the left frontal lobe virtually abolished this behavior, whereas lesions of the right frontal lobe produced excessive talking. These data suggest that the nature of the behavioral stimulus as well as the locus and side of damage must be considered in the study of the neural basis of affective behavior.
Carcinogen Testing: Current Problems and New Approaches
Authors: Weisburger John H. , Williams Gary M.
Published: October 2006

The classic procedures for testing potential carcinogens in animals have basically not changed in the past 50 years. Considerable knowledge of the mechanisms of carcinogenesis has accrued in the last 20 years, particularly concepts on the metabolic activation of chemicals to reactive electrophilic compounds that can interact with nucleophilic cell components including DNA. These developments, in turn, have yielded a framework for integrating into carcinogen testing the determination of genetic effects of chemicals. A systematic decision point approach to carcinogen testing has been developed which entails a sequential decision-making process as specific tests are performed and evaluated prior to initiation of higher order, more complex tests. Compared to conventional bioassays in rodents, this approach provides knowledge based on mechanisms of carcinogenesis, yields a substantial amount of data at minimal cost, and forms a solid base for eventual health risk assessment.
Persistent Behavior at High Rates Maintained by Intravenous Self-Administration of Nicotine
Authors: Goldberg Steven R. , Spealman Roger D. , Goldberg Donna M.
Published: October 2006

Squirrel monkeys pressed a lever at high rates under a second-order schedule of reinforcement in which lever pressing produced a brief visual stimulus that was occasionally contiguous with an intravenous injection of nicotine. The rate of lever pressing could be markedly reduced either by substituting saline for nicotine injections or by blocking the effects of nicotine with mecamylamine. The rate of lever pressing could also be reduced by eliminating the brief visual stimulus. These results show that nicotine can function as an effective reinforcer under a second-order schedule of drug self-administration and that an environmental stimulus associated with nicotine intake can contribute to the maintenance of persistent drug-seeking behavior.
Ranking Animal Carcinogens: A Proposed Regulatory Approach
Authors: Squire Robert A.
Published: October 2006

The nature and extent of positive evidence associated with animal carcinogens vary widely, yet present regulatory policy does not permit adequate discrimination among the many carcinogenic substances. Most are treated as if they pose equal potential risk to humans, and this is not consistent with the available data. Without knowledge of carcinogenic mechanisms, the evaluation of responses in intact mammalian surrogates best reflects the potential levels of human risk. An example of a scoring system is proposed by which animal carcinogens are ranked according to the most relevant toxicological evidence derived from animal and genotoxicity studies. Different classes of animal carcinogens could thus be recognized and would permit several regulatory options and provide a means to establish priorities for public and scientific concerns.
Firing Between Two Spike Thresholds: Implications for Oscillating Lobster Interneurons
Authors: Robertson R. M. , Moulins M.
Published: October 2006

An identified interneuron in the lobster commissural ganglia fires spikes only between membrane potential values of -60 and -30 millivolts. The membrane potential of this neuron can also oscillate, and interaction between these two properties has important implications in determining the firing pattern of the neuron itself and the modalities of driving of a distant postsynaptic neuron.
Angiotoxicity of Oxygenated Sterols and Possible Precursors
Authors: Imai Hideshige , Werthessen Nicholas T. , Subramanyam Vinayakam , LeQuesne Philip W. , Soloway Albert H. , Kanisawa Masayoshi
Published: October 2006

Cell death, inflammation, and repair in rabbits' aortas and pulmonary arteries were observed at 3-, 7-, and 10-day periods after the intravenous injection of oxygenated sterols. Thus, oxygenated sterols, not cholesterol, may play the primary role in arterial wall injury and lesion development.