bluuebunny/crossref_metadata_2025 huggingface dataset:
Interrelated Striated Elements in Vestibular Hair Cells of the Rat
Authors: Ross Muriel D. , Bourne Carol
Published: October 2006

Unusual fixation procedures revealed a series of interrelated striated organelles in type I and type II vestibular hair cells of the rat; these organelles seemed to be less well developed in cochlear hair cells. The findings suggest that contractile elements may play a role in sensory transduction in the inner ear, particularly in the vestibular system.
Intracellular Study of Human Epileptic Cortex: In Vitro Maintenance of Epileptiform Activity?
Authors: Schwartzkroin Philip A. , Knowles W. Douglas
Published: October 2006

Intracellular recordings were obtained in the in vitro slice preparation from neurons of lateral and mesial temporal cortex removed from human epileptics suffering from intractable temporal lobe seizures. Spontaneous rhythmic synaptic events, which were capable of triggering action potential discharge, were observed in many neurons, particularly in mesial tissue slices. Such activity may reflect the epileptogenic capacity of this human cortex.
Simian AIDS: Isolation of a Type D Retrovirus and Transmission of the Disease
Authors: Marx Preston A. , Maul Donald H. , Osborn Kent G. , Lerche Nicholas W. , Moody Peggy , Lowenstine Linda J. , Henrickson Roy V. , Arthur Larry O. , Gilden Raymond V. , Gravell Maneth , London William T. , Sever John L. , Levy Jay A. , Munn Robert J. , Gardner Murray B.
Published: October 2006

A type D retrovirus related to but distinct from Mason-Pfizer monkey virus was isolated in vitro from the blood of two rhesus monkeys (
Macaca mulatta
) with simian acquired immunodeficiency syndrome (SAIDS). Three juvenile rhesus monkeys that were injected intravenously with tissue culture fluids containing this virus developed SAIDS after 2 to 4 weeks.
Identification of an Infective Stage of
Leishmania
Promastigotes
Authors: Sacks David L. , Perkins Peter V.
Published: October 2006

Sequential development of
Leishmania
promastigotes from a noninfective to an infective stage was demonstrated for promastigotes growing in culture and in the sandfly vector. The generation of an infective stage was found to be growth cycle-dependent and restricted to nondividing organisms.
Metabolic Mapping of the Brain During Rewarding Self-Stimulation
Authors: Porrino Linda J. , Esposito Ralph U. , Seeger Thomas F. , Crane Alison M. , Pert Agu , Sokoloff Louis
Published: October 2006

Local rates of cerebral glucose utilization were measured in rats by the quantitative 2-deoxy-D-[
14
C]glucose autoradiographic method during electrical stimulation of the ventral tegmental area. Rats trained in intracranial self-stimulation showed a pattern of changes in forebrain metabolic activity distinctly different from the pattern seen in rats stimulated by the experimenter. These findings provide information about the distribution of local cerebral activity specific to reinforced instrumental behavior.
Vasoactive Intestinal Polypeptide-Like Substance: The Potential Transmitter for Cerebral Vasodilation
Authors: Lee Tony J-F. , Saito Akira , Berezin Irene
Published: October 2006

In vitro pharmacological studies demonstrated that exogenously applied vasoactive intestinal polypeptide (VIP) relaxes the smooth muscle cells of cat cerebral arteries, whereas substance P constricts them. Ultrastructural-immunocytochemical techniques show that a VIP-like substance is present in the large granular vesicles of nonsympathetic nerve axons and terminals in the cerebral arterial walls. These results provide strong evidence in favor of the hypothesis that a VIP-like substance is the transmitter for vasodilation in cerebral blood vessels.
Genetic Screening: Marvel or Menace?
Authors: Rowley Peter T.
Published: October 2006

Genetic screening is a systematic search in the population for persons of certain genotypes. The usual purpose is to detect persons who themselves or whose offspring are at risk for genetic diseases or genetically determined susceptibilities to environmental agents. Is genetic screening a marvel about to free us from the scourge of genetic disease or a menace about to invade our privacy and determine who may reproduce? There are three different types of genetic screening.
Newborn screening
identifies serious genetic disease at birth, permitting prompt treatment to prevent mental and physical retardation.
Fetal screening
and prenatal diagnosis identify genetic disease in the fetus permitting selective termination of pregnancy and the opportunity to have children free of defects detectable in utero.
Carrier screening
identifies individuals heterozygous for a gene for a serious recessive disease who may be at risk for affected offspring. The challenge to society is to provide (by way of cost-effective programs) expert services, including genetic counseling and follow-up, to all who may benefit, to ensure confidentiality and freedom of choice, and to avoid misunderstanding and stigmatization. It is recommended that the objective of screening programs should be to maximize the options available to families at risk rather than to reduce the incidence of genetic diseases. Whenever possible, the providers of these services should be the providers of primary health care. Urgently needed are a greater awareness of avoidable genetic diseases on the part of primary care providers and efforts to familiarize the public with the basic concepts of human genetics through the public school system.
Cell Sensitivity to Gravity
Authors: Cogoli A. , Tschopp A. , Fuchs-Bislin P.
Published: October 2006

Cultures of human lymphocytes exposed in microgravity to the mitogen concanavalin A showed less than 3 percent of the activation of ground controls. This result supports the hypothesis, based on simulations at low
g
and experiments at high
g
, that microgravity depresses whereas high gravity enhances cell proliferation rates. The effects of gravity are particularly strong in cells undergoing differentiation.
Analysis of Melatonin in Human Plasma by Gas Chromatography Negative Chemical Ionization Mass Spectrometry
Authors: Lewy Alfred J. , Markey S. P.
Published: October 2006

Three techniques have been used to measure human plasma melatonin: bioassay, radioimmunoassay, and gas chromatography-mass spectrometry (GC-MS). GC-MS is theoretically capable of the greatest specificity, but in general suffers from insufficient sensitivity. Negative chemical ionization, a new technique, provides a 150-fold increase in GC-MS sensitivity for electron-capturing compounds. Negative chemical ionization GC-MS permits routine measurement in human plasma of melatonin at a concentration as low as 1 picogram per milliliter.
Natural Antibodies to Human Retrovirus HTLV in a Cluster of Japanese Patients with Adult T Cell Leukemia
Authors: Robert-Guroff Marjorie , Nakao Yoshinobu , Notake Kunihiro , Ito Yohei , Sliski Ann , Gallo Robert C.
Published: October 2006

Human T cell lymphoma leukemia virus (HTLV) is a human retrovirus (RNA tumor virus) that was originally isolated from a few patients with leukemias or lymphomas involving mature T lymphocytes. Here we report that the serum of Japanese patients with adult T cell leukemia, but not the serum of tested normal donors, contains high titers of antibodies to HTLV. These observations, together with data from Japan showing that adult T cell leukemia is endemic in southwest Japan, suggest that HTLV is involved in a subtype of human T cell malignancy, including Japanese adult T cell leukemia.
L-Ornithine Decarboxylase: an Essential Role in Early Mammalian Embryogenesis
Authors: Fozard John R. , Part Marie-Louise , Prakash Nellikunja J. , Grove Jeffrey , Schechter Paul J. , Sjoerdsma Albert , Koch-Weser Jan
Published: October 2006

The highly selective, enzyme-activated, irreversible inhibitor of L-ornithine decarboxylase, DL-α-difluoromethylornithine, suppresses the increase in uterine L-ornithine decarboxylase activity associated with early embryogenesis in the mouse and arrests embryonic development at that stage. Contragestational effects were confirmed in the rat and rabbit. An increase in L-ornithine decarboxylase activity that leads to a rapid increase in putrescine concentration appears to be essential during a critical period after implantation for continued mammalian embryonal growth.
Giant Polytene Chromosomes from the Ovaries of a
Drosophila
Mutant
Authors: King Robert C. , Riley Shawn F. , Cassidy Joseph D. , White Peachie E. , Paik Yong K.
Published: October 2006

The chromosomes of the ovarian nurse cells of
Drosophila melanogaster
fall apart during their cycles of endoreduplication. However, chromosomal synapsis occurs in the pseudonurse cells produced in certain mutant females. The resulting polytene chromosomes undergo developmental changes that are strikingly different from those recorded for the giant chromosomes of the larval salivary gland cells.
Serum Albumin Beads: An Injectable, Biodegradable System for the Sustained Release of Drugs
Authors: Lee Timothy K. , Sokoloski Theodore D. , Royer Garfield P.
Published: October 2006

Biologically active compounds were entrapped in cross-linked serum albumin microbeads. Injection of these drug-impregnated beads into rabbits produced no adverse immunological reactions. Sustained release (20 days) of progesterone was demonstrated in vivo.
Atherosclerosis: Prevention by Agents Not Affecting Abnormal Levels of Blood Lipids
Authors: Kramsch Dieter M. , Aspen Anita J. , Rozler Lynn J.
Published: October 2006

Diet-induced atherosclerosis in macaque monkeys was suppressed by anticalcifying agents without changing abnormal levels of blood cholesterol and lipoprotein. The agents included inhibitors of arterial calcium deposition (diphosphonates) and a calcium ion antagonist (lanthanum). The study suggests that regulation of calcium flux and extracellular deposition in arteries may offer new principles of treatment for cardiovascular disease.
Preferential Attack of Mitochondrial DNA by Aflatoxin B
1
During Hepatocarcinogenesis
Authors: Niranjan B. G. , Bhat N. K. , Avadhani N. G.
Published: October 2006

Administration of the hepatic carcinogen aflatoxin B
1
to experimental animals results in covalent binding to liver mitochondrial DNA at concentrations three to four times higher than nuclear DNA. The concentration of carcinogen adducts in mitochondrial DNA remains unchanged even after 24 hours, possible because of lack of excision repair. Similarly, mitochondrial transcription and translation remain inhibited up to 24 hours suggesting long-term effects of aflatoxin B
1
on the mitochondrial genetic system.
Neuromagnetic Localization of Epileptiform Spike Activity in the Human Brain
Authors: Barth Daniel S. , Sutherling William , Engel Jerome , Beatty Jackson
Published: October 2006

Local paroxysmal discharges of epileptic tissue within the human brain, which may be electrically recorded as voltage spikes in the electroencephalogram, also generate extracranial magnetic fields. These fields were assessed by means of recently developed neuromagnetometric techniques. Surface measurements of magnetic spike field strength in the region of the focus appear sufficient to establish the location, depth, orientation, and polarity of currents underlying the paroxysmal discharge.
Transfusions of Whole Blood Prevent Spontaneous Diabetes Mellitus in the BB/W Rat
Authors: Rossini Aldo A. , Mordes John P. , Pelletier Anne M. , Like Arthur A.
Published: October 2006

Weekly transfusions of whole blood from a nondiabetic subline of BB/W rats reduced the incidence of diabetes in susceptible BB/W rats from 39 to 0 percent and the incidence of pancreatic insulitis from 64 to 6 percent. Responsiveness of lymphocytes to concanavalin A was found to be low in rats with diabetes or insulitis. Transfusion restored concanavalin A responsiveness to levels observed in control rats free of diabetes or insulitis. These data suggest that whole blood alters the course of autoimmune BB/W rat diabetes.
Human c-Ki-
ras
2 Proto-Oncogene on Chromosome 12
Authors: Sakaguchi Alan Y. , Naylor Susan L. , Shows Thomas B. , Toole John J. , McCoy Melissa , Weinberg Robert A.
Published: October 2006

A human colonic adenocarcinoma transforming gene, recently identified as a cellular homolog of the Kirsten sarcoma gene (v-
ras
), was used to assign the human cellular Kirsten
ras
2 gene to chromosome 12 by the Southern hybridization method. A single 640 base-pair Eco RI—Hind III fragment of the transforming gene, isolated by DNA transfection and molecular cloning, can detect a single Eco RI fragment (2.9 kilobase pairs) of DNA from phenotypically normal cells. The data suggest a constant chromosomal location of c-Ki-
ras
2.
Electrophoresis: Mathematical Modeling and Computer Simulation
Authors: Bier M. , Palusinski O. A. , Mosher R. A. , Saville D. A.
Published: October 2006

A mathematical model of electrophoretic separation processes has been developed and adapted for computer simulations. The model is used to predict the characteristic behavior of a variety of electrophoretic techniques from a knowledge of chemical equilibria and physical transport phenomena. The model provides a unifying basis for a rational classification of all electrophoretic processes.
Infant Intermodal Speech Perception Is a Left-Hemisphere Function
Authors: MacKain Kristine , Studdert-Kennedy Michael , Spieker Susan , Stern Daniel
Published: October 2006

Prelinguistic infants recognized structural correspondences in acoustic and optic properties of synchronized, naturally spoken disyllables, but did so only when they were looking to their right sides. This result suggests that intermodal speech perception is facilitated by rightward orientation of attention and subserved by the left hemisphere.
Formaldehyde Damage to DNA and Inhibition of DNA Repair in Human Bronchial Cells
Authors: Grafstrom Roland C. , Fornace Albert J. , Autrup Herman , Lechner John F. , Harris Curtis C.
Published: October 2006

Cultured bronchial epithelial and fibroblastic cells from humans were used to study DNA damage and toxicity caused by formaldehyde. Formaldehyde caused the formation of cross-links between DNA and proteins, caused single-strand breaks in DNA, and inhibited the resealing of single-strand breaks produced by ionizing radiation. Formaldehyde also inhibited the unscheduled DNA synthesis that occurs after exposure of cells to ultraviolet irradiation or to benzo[
a
]pyrene diolexpoxide but at doses substantially higher than those required to inhibit the resealing of x-ray-induced single-strand breaks. Therefore, formaldehyde could exert its mutagenic and carcinogenic effects by both damaging DNA and inhibiting DNA repair.
Endogenous Pyrogen Activity in Human Plasma After Exercise
Authors: Cannon Joseph G. , Kluger Matthew J.
Published: October 2006

Plasma obtained from human subjects after exercise and injected intraperitoneally into rats elevated rat rectal temperature and depressed plasma iron and zinc concentrations. The pyrogenic component was heat-denaturable and had an apparent molecular weight of 14,000 daltons. Human mononuclear leukocytes obtained after exercise and incubated in vitro released a factor into the medium that also elevated body temperature in rats and reduced trace metal concentrations. These results suggest that endogenous pyrogen, a protein mediator of fever and trace metal metabolism during infection, is released during exercise.
Experimental Transformation of Muscle Fiber Properties in Lobster
Authors: Lang Fred , Govind C. K. , Costello Walter J.
Published: October 2006

Like the chelipeds, the claw closer muscles of the adult lobster are asymmetric (dimorphic). In the crusher claw the closer muscle is composed entirely of slow fibers, and in the cutter claw it has 65 to 75 percent fast fibers and 25 to 35 percent slow fibers. While claw placement in the adult is essentially random, it can be demonstrated in two ways that the muscle fiber properties are not genetically fixed: (i) if one claw is removed in the fourth and early fifth stages, the remaining closer muscle develops all slow muscle fibers, and (ii) if the animals are raised in smooth-bottomed containers, both claws can become cutter types, having closer muscles with more than 50 percent fast fibers. Thus, as in vertebrate skeletal muscle, the properties of lobster closer muscle fibers can be transformed by various experimental manipulations.
Postnatally Induced Formation of the Corpus Callosum in Acallosal Mice on Glia-Coated Cellulose Bridges
Authors: Silver Jerry , Ogawa Michael Y.
Published: October 2006

Developing axons of the corpus callosum of mice are guided across the cerebral midline by a slinglike glial structure that forms transiently between the hemispheres. If the "sling" is cut at precallosal stages, the would-be callosal fibers whirl into paired neuromas adjacent to the longitudinal cerebral fissure. In experiments on such surgically acallosal animals, the aberrant commissural axons maintained a potential to regrow across the hemispheres at prenatal and early postnatal stages if they were presented with a properly aligned, glia-covered scaffold spanning the hemispheres.
Vaginal Stimulation: An Important Determinant of Maternal Bonding in Sheep
Authors: Keverne E. B. , Levy F. , Poindron P. , Lindsay D. R.
Published: October 2006

The immediate induction of the full complement of maternal behavior in nonpregnant ewes primed with estrogen and progesterone has been obtained after 5 minutes of vaginal-cervical stimulation. A similar period of such stimulation given to recently parturient ewes, after the development of selective bonding to their own lambs, reversed their rejection behavior of alien lambs and produced a state of plasticity in maternal behavior, such that ewes receiving vaginal stimulation would accept and adopt alien lambs. These findings implicate vaginal-cervical stimulation as playing a role in the onset of maternal behavior.
Taste Flashes: Reaction Times, Intensity, and Quality
Authors: Kelling Steven T. , Halpern Bruce P.
Published: October 2006

Human simple reaction times and magnitude estimates of taste intensity increased as the duration of 500-millimolar sodium chloride or 2-millimolar saccharin sodium pulses lengthened from 100 to 1000 milliseconds. Responses to "What was the taste?" ranged from 94 to 100 percent "sweet" for saccharin and 68 to 83 percent "salty" for salt across all pulse durations when both substances were randomized with water pulses.
Hyaluronate in Vasculogenesis
Authors: Feinberg Richard N. , Beebe David C.
Published: October 2006

Limb buds of chicken embryos contain within the peripheral mesoderm an avascular zone that is rich in hyaluronic acid. Epithelial tissues that synthesize large amounts of hyaluronic acid relative to other glycosaminoglycans caused avascularity when implanted into normally vascular wing mesoderm. Epithelia that synthesize little hyaluronic acid did not cause avascularity. Elvax implants containing hyaluronic acid caused the formation of avascular zones, whereas similar implants containing other glycosaminoglycans did not give rise to avascular zones. Hyaluronic acid may thus play a role in determining the location of blood vessels in the embryo.
Induction of Neuronal Branching in
Caenorhabditis elegans
Authors: Chalfie Martin , Thomson J. Nichol , Sulston John E.
Published: October 2006

The two postembryonic touch receptor neurons in the nematode
Caenorhabditis elegans
arise from essentially identical cell lineages and have the same ultrastructural features. The cells are found in different positions in the animal, however, and differ in neuronal branching, connectivity, and function. These structural and functional differences are not seen when cells are placed in similar positions by mutation or laser-induced damage. Thus, some, but probably not all, of the differentiated properties of these cells are a consequence of their cellular environment.
Direct in Vivo Monitoring of Dopamine Released from Two Striatal Compartments in the Rat
Authors: Ewing Andrew G. , Bigelow James C. , Wightman R. Mark
Published: October 2006

Microvoltammetric electrodes were used to monitor dopamine released in the caudate nucleus of the rat after electrical stimulation of the medial forebrain bundle. The time resolution of the technique is sufficient to determine in vivo concentration changes on a time scale of seconds. Direct evidence identifying the substance released as dopamine was obtained both voltammetrically and pharmacologically. Administration of α-methyl-p-tyrosine terminates the release of dopamine, although tissue stores of dopamine are still present. Thus there appears to be a compartment for dopamine storage that is not available for immediate release. This compartment appears to be mobilized by amfonelic acid, since administration of this agent after α-methyl-p-tyrosine returns the concentration of dopamine released by electrical stimulation to 75 percent of the original amount.
Hepatitis B Virus Infection in Cultured Human Lymphoblastoid Cells
Authors: Romet-Lemonne Jean-Loup , McLane Mary Frances , Elfassi Emile , Haseltine William A. , Azocar José , Essex Myron
Published: October 2006

Since it has been postulated that liver hepatocytes may become infected by hepatitis B virus (HBV) in vivo through direct contact with infected macrophages, the possibility that a circulating cell of hematopoietic origin might be susceptible to infection with HBV was investigated. Cells positive for HBV surface antigen were identified in aspirates of bone marrow cells from people infected with HBV. These cells were used to prepare a lymphoblastoid suspension culture that contains HBV-infected cells.
Ground Water Contamination in the United States
Authors: Pye Veronica I. , Patrick Ruth
Published: October 2006

Ground water contamination is of increasing concern in the United States because about 50 percent of our drinking water comes from well water. The causes of contamination stem from both point sources and nonpoint sources. Since ground water moves slowly, the contaminant may affect only a small portion of an aquifer for a considerable period of time. Deleterious effects on human health have resulted from pathogenic organisms in ground water and from its toxic chemical composition. It is difficult to estimate the extent of contamination on a national basis as the frequency of instances of contamination is very variable. Remedial actions to clean up aquifers are difficult, expensive, and sometimes not feasible. Many of the laws and regulations that control ground water contamination are designed with other main objectives.
Performance of Concurrent Tasks: A Psychophysiological Analysis of the Reciprocity of Information-Processing Resources
Authors: Wickens Christopher , Kramer Arthur , Vanasse Linda , Donchin Emanuel
Published: October 2006

The resources allocated to a primary and secondary task are reciprocal. Subjects performed a tracking task in which the discrete displacements of the tracking cursor could be used to elicit event-related brain potentials. As the resource demands of the tracking task were increased, potentials elicited by the task-defined events increased in amplitude, whereas those elicited by secondary task auditory stimuli decreased.
Phototherapy-Induced Hypocalcemia in Newborn Rats: Prevention by Melatonin
Authors: Hakanson David O. , Bergstrom William H.
Published: October 2006

When young rats are exposed to white fluorescent light the concentration of calcium in their serum decreases. This effect is prevented by shielding the occiput, by inhibiting corticosterone synthesis, and by exogenous melatonin. Furthermore, the expected hypocalcemic response to cortisol injection is prevented by melatonin. Light-induced hypocalcemia may result from increased calcium uptake by bone when the blocking effect of melatonin decreases after pineal inhibition by transcranial illumination.
Modification of Attention in Honey Bees
Authors: Klosterhalfen S. , Fischer W. , Bitterman M. E.
Published: October 2006

Honey bees were trained in two consecutive two-dimensional (color-position) problems with one dimension (color or position) relevant and the other irrelevant in each problem. As in analogous experiments on dimensional transfer in rats and monkeys, performance in the second problem was more accurate when the relevant and irrelevant dimensions were the same as in the first problem than when they were interchanged. The results of further experiments suggest that the transfer is mediated by different modes of responding that develop in color and position problems rather than by some special process of dimensional selection, such as has been assumed to operate in vertebrates.
Evidence for the Clonal Origin of Spontaneous Metastases
Authors: Talmadge James E. , Wolman Sandra R. , Fidler Isaiah J.
Published: October 2006

A cultured cell line of the K-1735 melanoma was x-irradiated to induce chromosome breakage and rearrangements and then was implanted into the footpads of syngenic C3H mice. Spontaneous lung metastases were isolated from different animals, established in culture as individual lines, and then karyotyped. Within certain metastases, the same chromosomal abnormality (or abnormalities) (recombinant chromosomes) was found in all the cells examined. Most metastases differed from one another in that they exhibited characteristic combinations of chromosomal markers. These findings indicated that the metastases were clonal and that they probably originated from different progenitor cells.
Brain Target Sites for 1,25-Dihydroxyvitamin D
3
Authors: Stumpf Walter E. , Sar Madhabananda , Clark Samuel A. , DeLuca Hector F.
Published: October 2006

Autoradiographic studies with
3
H-labeled 1,25-dihydroxyvitamin D
3
[1,25(OH)
2
D
3
] demonstrate, in certain neurons of rat forebrain, hindbrain, and spinal cord, a nuclear retention and concentration of radioactivity, which can be prevented by treatment with 1,25(OH)
2
D
3
, but not with 25-hydroxyvitamin D
3
. These results indicate the presence of brain receptors in addition to pituitary receptors for 1,25(OH)
2
D
3
and suggest a central modulation of calcium homeostasis and other central effects for this hormone. The existence of a brain-pituitary axis for certain 1,25(OH)
2
D
3
-mediated endocrine-autonomic effects is postulated.
24-Hydroxylation of 25-Hydroxyvitamin D
3
: Is It Required for Embryonic Development in Chicks?
Authors: Ameenuddin Syed , Sunde Milton , DeLuca Hector F. , Ikekawa Nobuo , Kobayashi Yoshiro
Published: October 2006

As shown previously, laying hens given 1,25-dihydroxyvitamin D
3
as their sole source of vitamin D produce fertile eggs having normal shells, but only 35 to 55 percent of the embryos are normal. Giving these hens additional 25-hydroxyvitamin D
3
, 24,25-dihydroxyvitamin D
3
, or 24,24-difluoro-25-hydroxyvitamin D
3
at 1.25 nanomoles per day resulted in 90 to 100 percent normal embryos, and hence, hatchability. Since 24,24-difluoro-25-hydroxyvitamin D
3
cannot be 24-hydroxylated, 24-hydroxylation is not required for this function of 25-hydroxyvitamin D
3
.
Renin-Specific Antibody for Study of Cardiovascular Homeostasis
Authors: Dzau Victor J. , Kopelman Richard I. , Barger A. Clifford , Haber Edgar
Published: October 2006

Antiserum specific for purified canine renal renin was used to inhibit this enzyme in trained, conscious dogs. The antiserum did not affect blood pressure in sodium-replete dogs but decreased plasma renin activity and blood pressure in sodium-depleted animals. The antiserum also reduced blood pressure to control levels concomitant with suppression of plasma renin activity in uninephrectomized dogs with acute renovascular hypertension. These observations establish the role of the renin-angiotensin system in the maintenance of blood pressure in the sodium-depleted state as well as in the initiation of renovascular hypertension.
Lead in Albacore: Guide to Lead Pollution in Americans
Authors: Settle Dorothy M. , Patterson Clair C.
Published: October 2006

Lead contamination in canned tuna, exceeding natural concentrations 10,000-fold, went undiscovered for decades because of analytical error. The magnitude of this pollution effect helps explain the difference between the lead concentration in the diets of present-day Americans (0.2 part per million) and in the diets of prehistoric peoples (estimated to be less than 0.002 part per million). It also explains how skeletal concentrations of lead in typical Americans became elevated 500-fold above the natural concentrations measured in bones of Peruvians who lived in an unpolluted environment 1800 years ago. It has been tacitly assumed that natural biochemical effects of lead in human cells have been studied, but this is not so because reagents, nutrients, and controls used in laboratory and field studies have been unknowingly contaminated with lead far in excess of naturally occurring levels. An unrecognized form of poisoning caused by this excessive exposure to lead may affect most Americans because magnitudes of biochemical dysfunctions are proportional to degrees of exposure.
Genetic Diversity and Structure in
Escherichia coli
Populations
Authors: Selander Robert K. , Levin Bruce R.
Published: October 2006

A survey of electrophoretic variation in 20 enzymes from 109 clones of
Escherichia coli
from natural populations yielded an estimate of mean genetic diversity approximately twice that reported in an earlier study and four to five times larger than estimates for most eukaryotic species. Despite this extensive variability, the number of distinctive genotypes apparently is rather limited. Identical clones were obtained from unassociated hosts, and a clone that is electrophoretically indistinguishable from the laboratory strain
Escherichia coli
K-12 was isolated from a human infant. The results suggest that rates of genetic recombination in natural populations of
Escherichia coli
are low. These findings have implications for our understanding of the genetic structure of
Escherichia coli
populations and the factors determining the amount of neutral gene variability in this bacterial species.
Prostacyclin: A Potent Antimetastatic Agent
Authors: Honn Kenneth V. , Cicone Bruce , Skoff Anne
Published: October 2006

Metastasis is the principal cause of failures to cure human cancers. Prostacyclin is a powerful antimetastatic agent against B16 amelanotic melanoma cells. This effect, which may result from the platelet antiaggregatory action of prostacyclin, is potentiated by a phosphodiesterase inhibitor. Inhibitors of prostacyclin synthesis increase metastasis. Prostacyclin and agents that may increase endogenous prostacyclin production or prolong its activity are suggested as new antimetastatic agents.
Primary Structure of a Large Aminoacyl-tRNA Synthetase
Authors: Putney Scott D. , Royal Nancy J. , de Vegvar Henry Neuman , Herlihy Walter C. , Biemann K. , Schimmel Paul
Published: October 2006

The complete primary structure of
Escherichia coli
alanyl-tRNA synthetase, a 95,000-dalton polypeptide, was established by sequencing the gene encoding the enzyme and by sequencing oligopeptides in hydrolyzates of the protein by gas chromatography-mass spectrometry. Contrary to expectation, this long polypeptide contains no lengthy duplications. One 13-residue peptide is homologous with
Escherichia coli
tyrosyl-tRNA synthetase, and clusters of charged amino acids occur in several sections of the structure.
American Medicine's Golden Age: What Happened to It?
Authors: Burnham John C.
Published: October 2006

In the first half of the 20th century, American physicians enjoyed relative freedom from adverse comment in mass and highbrow media. In unexpected ways the physicians' high ideals and the campaigns against socialized medicine brought criticism not only of the priestly but also of the technical functions of the medical profession. In the late 1950's this led to a campaign to modify the elevated position of physicians in American society.
A Virally Induced Obesity Syndrome in Mice
Authors: Lyons Michael J. , Faust Irving M. , Hemmes Richard B. , Buskirk Daniel R. , Hirsch Jules , Zabriskie John B.
Published: October 2006

An obesity syndrome was found in a number of mice infected as young adults with canine distemper virus, a morbillivirus antigenically related to measles. Body weights of obese animals 16 to 20 weeks after infection were comparable to those reported for genetically obese mice and for mice rendered obese by hypothalamic lesions. The total number of adipocytes in specific fat deposits was greater in obese animals than in their lean littermates. This hyperplasia was accompanied by moderate cell enlargement. Pancreatic islet tissue was also hypercellular in the obese mice. Brain tissue from the obese mice showed no overt pathology, and immunofluorescence staining for viral antigens was negative. There may be a selective, virus-induced disruption of critical brain catecholamine pathways.
Prenatal Exposure to the Herbicide 2,4-Dichlorophenyl-
p
-Nitrophenyl Ether Destroys the Rodent Harderian Gland
Authors: Gray Leon Earl , Kavlock Robert J. , Chernoff Neil , Ferrell Janet , McLamb Joey , Ostby Joseph
Published: October 2006

Exposure of mice to the herbicide 2,4-dichlorophenyl-
p
-nitrophenyl ether during gestation produces abnormalities that are not readily apparent at birth but become obvious as the pups mature. By 2 weeks after birth there are severe intraorbital defects resulting from destruction of the Harderian glands behind the eyes. This effect is noticeable only postnatally because the Harderian gland does not grow or function until after birth.
Cyclic Biological Expression in Mouse Mammary Tumors
Authors: Kiang David T. , King Margaret , Zhang Hui-Jian , Kennedy B. J. , Wang Nancy
Published: October 2006

Biological characteristics were assessed in GR mouse mammary tumors during 22 serial transplantations. Although unidirectional progression from hormone dependency to independency was observed, other biological markers such as progesterone receptors, polyploid frequency, and thymidine kinase activity demonstrated cyclic phenomena every fourth to sixth transplant generation, suggesting the continued presence of regulatory mechanisms among various cell subpopulations.
Interspecies Variations in Mammalian Lens Metabolites as Detected by Phosphorus-31 Nuclear Magnetic Resonance
Authors: Kopp Stephen J. , Glonek Thomas , Greiner Jack V.
Published: October 2006

Multiple interspecies differences were detected between humans and seven other mammals in 15 of the 24 metabolites measured in the intact crystalline lens and lens perchloric acid extracts. Generally, the number of statistically significant metabolite differences among the various species, relative to the human, increase in the following order: cat ∼ dog > pig > rat > sheep > rabbit > cow.
Synaptic Cleft Glycoproteins Contain Homologous Amino Acid Sequences
Authors: Mena E. Edward , Cotman Carl W.
Published: October 2006

The concanavalin A--binding glycoproteins of the rat synaptic junction were isolated by affinity chromatography. These glycoproteins had molecular weights of 160,000, 123,000, 110,000, and 95,000. The tryptic peptide maps of these glycoproteins showed that the three largest glycoproteins contained a high percentage of identical peptides. This indicates that the amino acid sequences of these glycoproteins have a high degree of homology. The 95,000-dalton glycoprotein was unrelated to the other three. These findings suggest that homologous glycoproteins may participate in synapse formation or maintenance, or both.
Intellectual Property: The Control of Scientific Information
Authors: Nelkin Dorothy
Published: October 2006

Control of scientific information is increasingly at the center of legal and administrative disputes, raising questions of sovereignty and secrecy, of proprietary rights over research. Disputes originate from efforts to extend the right of access to data at an early stage of research, from demands for information that threaten confidentiality, from proprietary interests in competitive areas of research, and from government restrictions on the free exchange of scientific ideas. They reflect policy changes with respect to information disclosure, university-industry collaboration, patent rights, and national security. A review of diverse situations that have led to disputes and of efforts to negotiate principles for controlling intellectual property suggests the problems of establishing such principles in the context of the changing role of science.
In Vitro Evidence for Two Distinct Hippocampal Growth Factors: Basis of Neuronal Plasticity?
Authors: Crutcher Keith A. , Collins Frank
Published: October 2006

The rat hippocampal formation was tested for the presence of factors that would accelerate neurite extension from chick parasympathetic (ciliary ganglion) or sympathetic (lumbar chain) neurons in vitro. Two growth factors were identified in extracts of this brain region. One accelerated neurite extension from sympathetic neurons and was blocked by antiserum to nerve growth factor. The other accelerated neurite extension from parasympathetic neurons but was not affected by the antiserum. These results suggest that specific growth factors account for the specificity of neuronal sprouting.
Amphetamine, Haloperidol, and Experience Interact to Affect Rate of Recovery After Motor Cortex Injury
Authors: Feeney Dennis M. , Gonzalez Abel , Law Wendy A.
Published: October 2006

Rats subjected to unilateral ablation of the motor cortex and placed on a narrow beam displayed transient contralateral paresis. An immediate and enduring acceleration of recovery was produced by a single dose ofd-amphetamine given 24 hours after injury. This effect was blocked by haloperidol or by restraining the animals for 8 hours beginning immediately after amphetamine administration. A single dose of haloperidol given 24 hours after injury markedly slowed recovery. This effect was also blocked by restraining the animals.
Velocity Signals Related to Hand Movements Recorded from Red Nucleus Neurons in Monkeys
Authors: Kohlerman N. J. , Gibson A. R. , Houk J. C.
Published: October 2006

Neural activity of the red nucleus was studied in monkeys trained to operate devices requiring shoulder, elbow, wrist, hand, or finger movements. Single cell activity was more closely related to movements of the hand and fingers than to movements of the other joints. Discharge consistently preceded movements by a constant time interval; duration of discharge was highly correlated with the duration of movement; and discharge rate was highly correlated with movement velocity. These data suggest a role for the rubrospinal pathway in the initiation and control of hand movements.
Occlusal Variation Related to Soft Diet in a Nonhuman Primate
Authors: Corruccini Robert S. , Beecher Robert M.
Published: October 2006

Among 43 squirrel monkeys (
Saimiri sciureus
) raised either on naturally tough or on artificially soft foods, there are significant differences in occlusal features. Animals raised on soft foods show more rotated and displaced teeth, crowded premolars, and absolutely and relatively narrower dental arches. Dietary consistency may be a determinant of occlusal health.
Electric and Magnetic Field Detection in Elasmobranch Fishes
Authors: Kalmijn Ad. J.
Published: October 2006

Sharks, skates, and rays receive electrical information about the positions of their prey, the drift of ocean currents, and their magnetic compass headings. At sea, dogfish and blue sharks were observed to execute apparent feeding responses to dipole electric fields designed to mimic prey. In training experiments, stingrays showed the ability to orient relative to uniform electric fields similar to those produced by ocean currents. Voltage gradients of only 5 nanovolts per centimeter would elicit either behavior.
Rhodamine-123 Selectively Reduces Clonal Growth of Carcinoma Cells in Vitro
Authors: Bernal Samuel D. , Lampidis Theodore J. , Summerhayes Ian C. , Chen Lan Bo
Published: October 2006

Rhodamine-123, a cationic laser dye, markedly reduced the clonal growth of carcinoma cells but had little effect on nontumorigenic epithelial cells in vitro. This selective inhibitory effect of Rhodamine-123 on some carcinomas is unusual since known anticancer drugs, such as arabinosyl cytosine and methotrexate, have not been shown to exhibit such selectivity in vitro.
Virus-Induced Alterations in Homeostasis: Alteration in Differentiated Functions of Infected Cells in Vivo
Authors: Oldstone Michael B. A. , Sinha Y. N. , Blount Paul , Tishon Antoinette , Rodriguez Moses , von Wedel Randall , Lampert Peter W.
Published: October 2006

The noncytopathic lymphocytic choriomeningitis virus displays a tropism for the anterior lobe of the murine pituitary gland. Virus replicates in cells that make growth hormone. This results in a diminished synthesis of growth hormone with a concomitant clinical picture of retarded growth and hypoglycemia. However, there is no morphologic evidence of either cell necrosis or inflammation in the anterior lobe of the pituitary. Hence, during infection in vivo, a noncytopathic virus may turn off the "differentiation" or "luxury" function of a cell while not killing that cell (loss of vital function). This in turn can disrupt homeostasis and cause disease. This model illustrates a novel way whereby viruses may cause disease.
Substantia Nigra: Site of Anticonvulsant Activity Mediated by γ-Aminobutyric Acid
Authors: Iadarola Michael J. , Gale Karen
Published: October 2006

Localization of the anatomic substrate for anticonvulsant activity mediated by γ-aminobutyric acid (GABA) was examined using intracerebral injections of GABA agonists. Blockade of tonic hindlimb extension in the maximal electroshock test and blockade of tonic and clonic seizures produced by pentylenetetrazole and bicuculline were obtained by elevating GABA in the ventral midbrain tegmentum. Elevation of GABA in forebrain and hindbrain areas had no effect on convulsant activity. Blockade of tonic and clonic seizures was also obtained after microinjections of the direct GABA receptor agonist, muscimol, into the midbrain. The substantia nigra was identified as the critical midbrain site for GABA-mediated anticonvulsant activity. Local injection of GABA agonists into the midbrain provided seizure protection without a widespread augmentation of GABA-mediated activity throughout the brain and without impairing either alertness or motor function. Synapses in the substantia nigra appear to represent an important control mechanism for inhibiting the propagation of generalized convulsions.
Transient Raman Study of Hemoglobin: Structural Dependence of the Iron-Histidine Linkage
Authors: Friedman J. M. , Rousseau D. L. , Ondrias M. R. , Stepnoski R. A.
Published: October 2006

Low-frequency resonance Raman spectra of transient hemoglobin species were observed within 10 nanoseconds of photolysis. The Raman frequencies of the iron-proximal histidine stretching mode for transient species having either the R or the T quaternary structure are higher than in the corresponding deoxy species. The observed frequency difference in the iron-histidine mode between the R- and T- state transients indicates that there are quaternary structure-dependent protein forces on the iron-histidine bond in the liganded hemoglobins. These differences are interpreted in terms of changes in the tilt of the histidine with respect to the heme plane.
Puberty Delay by a Urinary Cue from Female House Mice in Feral Populations
Authors: Massey Adrianne , Vandenbergh John G.
Published: October 2006

Urine produced by wild female house mice, living in high- and low-density populations and confined to areas within a highway cloverleaf, was tested for its ability to delay puberty in juvenile female mice. Only urine collected from females in the dense population at its maximum density delayed puberty in test females. Urine collected when the population was less dense, or from a population that remained sparse, failed to delay puberty. These results suggest that a urinary factor present at high densities may delay puberty and thus help to slow further population growth.
Genetic Studies of an Acardiac Monster: Evidence of Polar Body Twinning in Man
Authors: Bieber Frederick R. , Nance Walter E. , Morton Cynthia C. , Brown Judith A. , Redwine Fay O. , Jordan Robert L. , Mohanakumar T.
Published: October 2006

Two maternally derived chromosome sets and both maternal histocompatibility antigen haplotypes were identified in the tissues of a malformed triploid acardiac twin that developed within the same chorion as its normal twin. These findings indicate that the twins arose as a result of independent fertilizations, by two different spermatozoa, of a normal haploid ovum and its diploid first-meiotic-division polar body.
Visual Claustrum: Topography and Receptive Field Properties in the Cat
Authors: Sherk H. , LeVay S.
Published: October 2006

A region containing visually responsive cells was found in the dorsocaudal claustrum. This area contains a single orderly map of the contralateral visual field. Like cortical cells, most claustral cells are selective for stimulus orientation. They are binocular, and they respond to either direction of movement and to a broad range of velocities. Their most striking property is a marked preference for very long stimuli.
Circadian Variation in the Latency of Brainstem Responses and Its Relation to Body Temperature
Authors: Marshall Noel K. , Donchin Emanuel
Published: October 2006

The auditory brainstem response varies in a circadian rhythm that is negatively correlated with the circadian rhythm in oral temperature. The auditory brainstem responses and oral temperature were recorded every 3 hours from three healthy male subjects during a 2-day period. The data indicate that a reduction of 1°C in oral temperature is associated with an increase of 200 microseconds in the latency of wave V of the auditory brainstem response, and of 160 microseconds in the interval between waves I and V.
Isoguanosine: Isolation from an Animal
Authors: Fuhrman Frederick A. , Fuhrman Geraldine J. , Nachman Ronald J. , Mosher Harry S.
Published: October 2006

Isoguanosine (oxyadenosine or crotonoside), previously known to occur in nature only in the croton bean, was isolated from an animal, the marine nudibranch mollusk
Diaulula sandiegensis
.
Eusociality in a Mammal: Cooperative Breeding in Naked Mole-Rat Colonies
Authors: Jarvis J. U. M.
Published: October 2006

Laboratory observations on a field-collected colony of 40
Heterocephalus
have shown that only a single female breeds. The remaining individuals constitute two or three castes, each containing both sexes and distinguishable by size differences and the tasks they perform. These features, together with long life-spans, overlap of generations, cooperative brood care, and possible age polyethism provide parallels with the eusocial insects.
The Prolactin Gene Is Located on Chromosome 6 iIn Humans
Authors: Owerbach David , Rutter William J. , Cooke Nancy E. , Martial Joseph A. , Shows Thomas B.
Published: October 2006

The gene for prolactin has been located on chromosome 6 in humans. DNA fragments of 4.8 and 4.0 kilobases containing prolactin gene sequences were identified in human genomic DNA, whereas DNA fragments of 7.4, 3.6, and 3.3 kilobases containing prolactin gene sequences were found in mouse cells. In somatic cell hybrids of human and mouse cells the 7.4-, 3.6-, and 3.3-kilobase mouse fragments were always present, whereas the 4.8- and 4.0-kilobase human fragments were only present when human chromosome 6 was also present. We conclude that the prolactin gene resides on chromosome 6, a different location from those of the genes for the related hormones chorionic somatomammotropin and growth hormone.