bluuebunny/crossref_metadata_2025 huggingface dataset:
Assembly of Proteins into Membranes
Authors: Wickner William
Published: October 2006

Two pathways for protein assembly into biological membranes have been proposed. The "signal hypothesis" emphasizes the role of specific membrane proteins in binding the growing polypeptide and conducting it into the bilayer during its synthesis. The "membrane-triggered folding" hypothesis emphasizes self-assembly and the role of changing protein conformation during transfer from an aqueous compartment into a membrane. These ideas provide a framework for reviewing recent data on the biogenesis of membrane proteins.
Echo Detection and Target-Ranging Neurons in the Auditory System of the Bat
Eptesicus fuscus
Authors: Feng A. S. , Simmons J. A. , Kick S. A.
Published: October 2006

Some of the neurons in the nucleus intercollicularis and auditory cortex of the echolocating bat
Eptesicus fuscus
respond selectively to sonar echoes occurring with specific echo delays or pulse-echo intervals. They do not respond for a wide range of other types of sounds or for sonar echoes at longer or shorter pulse-echo intervals; they may, therefore, be specialized for detection and ranging of sonar targets.
Directly Transmitted Infections Diseases: Control by Vaccination
Authors: Anderson Roy M. , May Robert M.
Published: October 2006

Mathematical models for the dynamics of directly transmitted viral and bacterial infections are guides to the understanding of observed patterns in the age specific incidence of some common childhood diseases of humans, before and after the advent of vaccination programs. For those infections that show recurrent epidemic behavior, the interepidemic period can be related to parameters characterizing the infection (such as latent and infectious periods and the average age of first infection); this relation agrees with the data for a variety of childhood diseases. Criteria for the eradication of a disease are given, in terms of the proportion of the population to be vaccinated and the age-specific vaccination schedule. These criteria are compared with a detailed analysis of the vaccination programs against measles and whooping cough in Britain, and estimates are made of the levels of protection that would be needed to eradicate these diseases.
Electric Pulse-Induced Fusion of 3T3 Cells in Monolayer Culture
Authors: Teissie J. , Knutson V. P. , Tsong T. Y. , Lane M. D.
Published: October 2006

Swiss mouse 3T3-C2 fibroblasts, grown to confluence in monolayer culture, are shown to fuse when exposed to electric fields. Exposure to five repetitive electric pulses of about 1 kilovolt per centimeter with a duration of 50 microseconds caused approximately 20 percent of the cells to become fused (multinucleate) when 1 millimolar magnesium was present in the medium. The effects of minimum thresholds of field strength, pulse duration, and number of pulses were determined. Cell disruption was observed when the electric field exceeded 2.0 kilovolts per centimeter or the pulse was of longer duration than 120 microseconds.
Decreased Nocturnal Plasma Melatonin Peak in Patients with Estrogen Receptor Positive Breast Cancer
Authors: Tamarkin Lawrence , Danforth David , Lichter Alan , DeMoss Ernest , Cohen Michael , Chabner Bruce , Lippman Marc
Published: October 2006

Plasma melatonin concentrations were determined over a period of 24 hours in 20 women with clinical stage I or II breast cancer. In ten of the patients, whose tumors were estrogen receptor positive, the nocturnal increase in plasma melatonin was much lower than that observed in eight control subjects. Women with the lowest peak concentration of melatonin had tumors with the highest concentrations of estrogen receptors. A significant correlation was found between the peak plasma melatonin concentration and the tumor estrogen receptor concentration in 19 of the patients. These data suggest that low nocturnal melatonin concentrations may indicate the presence of estrogen receptor positive breast cancer and could conceivably have etiologic significance.
Monkey and Human Pictorial Memory Scanning
Authors: Sands Stephen F. , Wright Anthony A.
Published: October 2006

A rhesus monkey accurately recognized pictures in a Sternberg memory scanning experiment. When the monkey was tested with pictures that were reused during the same session, the monkey's performance was nearly identical to that of a human subject; this result demonstrates that monkeys are capable of some of the short-term retrieval mechanisms of humans.
Morphologic Effect of Dimethyl Sulfoxide on the Blood-Brain Barrier
Authors: Broadwell Richard D. , Salcman Michael , Kaplan Richard S.
Published: October 2006

Dimethyl sulfoxide (DMSO) opens the blood-brain barrier of mice to the enzymatic tracer horseradish peroxidase. A single injection of horseradish peroxidase in 10 to 15 percent DMSO into the tail vein along with 10 to 15 percent DMSO delivered intraperitoneally allowed horseradish peroxidase to fill the extracellular clefts throughout the brain within 2 hours. In the absence of DMSO, peroxidase failed to enter brain parenchyma except through the circumventricular organs. Opening of the blood-brain barrier by DMSO is reversible. Dimethyl sulfoxide stimulated the pinocytosis of horseradish peroxidase by the cerebral endothelium; the peroxidase was then directed to lysosomal dense bodies for degradation. Vesicular transport of horseradish peroxidase from the luminal to the abluminal wall of the endothelial cell was not observed. Dimethyl sulfoxide did not alter the morphology of endothelial cells or brain parenchyma.
Spiking Local Interneurons Mediate Local Reflexes
Authors: Burrows M. , Siegler M. V. S.
Published: October 2006

A local spiking interneuron in the locust is excited by particular sensory stimulation of a hind leg and forms an inhibitory connection with one hind leg motor neuron. Its behavioral effect is to mediate a local postural reflex. This interneuron is one of a population of interneurons with similar morphology and physiology that participate in the same local circuits as the better known nonspiking local interneurons.
Occurrence of Germanium and Arsenic in Meteorites
Authors: Papish Jacob , Hanford Zaida M.
Published: October 2006

1. Spectroscopic evidence has been obtained of the occurrence of germanium in certain siderites, siderolites and aerolites.

2. Judging from the number and intensity of spectral lines the germanium in these meteorites is present in traces.

3. Germanium has been extracted from Toluca and Welland siderites.

4. Arsenic has been extracted from Toluca and Welland siderites
Serial Position Curve in Rats: Role of the Dorsal Hippocampus
Authors: Kesner Raymond P. , Novak Jeanne M.
Published: October 2006

In an eight-arm radial maze, normal rats demonstrated good immediate retention for the order of first items (primacy component of serial position curve) and last items (recency component of serial position curve) of an eight-item (arm) list. In contrast, rats with dorsal hippocampal lesions displayed, on an immediate retention test, disruption of the primacy but not the recency component of the serial position curve. Furthermore, imposing a 10-minute delay before the retention test impaired all components of the serial position curve. These results support correspondence in mnemonic function of the hippocampus in animals and humans.
Monoclonal Antibody to 5-Bromo- and 5-Iododeoxyuridine: A New Reagent for Detection of DNA Replication
Authors: Gratzner Howard G.
Published: October 2006

Monoclonal antibodies specific for 5-bromodeoxyuridine have been produced and applied in detecting low levels of DNA replication on a cell-by-cell basis in vitro. The immunoglobulin-producing hybridomas were derived from spleen cells of mice immunized with a conjugate of iodouridine and ovalbumin. The cells were fused with the plasmacytoma line SP2/0Ag14. The antibodies produced are highly specific for bromodeoxyuridine and iododeoxyuridine and do not cross-react with thymidine. DNA synthesis in cultured cells exposed to bromodeoxyuridine for as short a time as 6 minutes can be detected easily and rapidly by an immunofluorescent staining method and quantitated by flow cytometry.
Asymmetrical Brain Activity Discriminates Between Positive and Negative Affective Stimuli in Human Infants
Authors: Davidson Richard J. , Fox Nathan A.
Published: October 2006

Ten-month-old infants viewed videotape segments of an actress spontaneously generating a happy or sad facial expression. Brain activity was recorded from the left and right frontal and parietal scalp regions. In two studies, infants showed greater activation of the left frontal than of the right frontal area in response to the happy segments. Parietal asymmetry failed to discriminate between the conditions. Differential lateralization of the hemispheres for affective processes seems to be established by 10 months of age.
Free and Forced Diving in Birds
Authors: Kanwisher John W. , Gabrielsen Geir , Kanwisher Nancy
Published: October 2006

Heart rates were measured during free and forced diving on each of two species of aquatic birds: the double-crested cormorant (
Phalacrocorax auritus
), a true diver, and the Canada goose (
Branta canadensis
), a bottom feeder in shallow water. When they immersed voluntarily they showed no bradycardia, but when the same birds were forcibly held under water there was a rapid drop in heart rate to well below that at rest. This decrease indicates that there may be a large component of emotional stress in the heart rate records from previous diving studies where restrained animals were forcibly submerged.
Intravenous Self-Administration of Nomifensine in Rats: Implications for Abuse Potential in Humans
Authors: Spyraki C. , Fibiger H. C.
Published: October 2006

Rats acquired and maintained intravenous self-administration of nomifensine, a new antidepressant compound. Additional experiments implicated dopamine-containing neurons in this behavior. These findings, along with the marked pharmacological similarities between nomifensine and such drugs as cocaine and methylphenidate, indicate a potential for nomifensine abuse by humans.
Alcohol-Dependent Liver Cell Necrosis in Vitro: A New Model
Authors: Schanne Francis A. X. , Zucker Amy H. , Farber John L. , Rubin Emanuel
Published: October 2006

In alcoholic liver injury, necrosis is involved in the progression from benign fatty liver to alcoholic hepatitis and cirrhosis. However, there is no practical model of alcohol-dependent liver cell necrosis. The calcium-dependent killing of cultured rat hepatocytes by two different membrane-active hepatotoxins, galactosamine and phalloidin, is potentiated by ethyl alcohol. This indicates that some general physical effect of alcohol on cellular membranes renders cells susceptible to otherwise nonlethal injuries. The in vitro model described in this report may thus be used to search for a general mechanism underlying alcohol-related tissue injury.
Electroreception in Lampreys: Evidence That the Earliest Vertebrates Were Electroreceptive
Authors: Bodznick David , Northcutt R. Glenn
Published: October 2006

Evoked potential and unit responses from the lamprey brain to weak electric fields demonstrate that lampreys have an electrosensory system as sensitive as those of other electroreceptive fishes. Electrosensory responses were recorded in the dorsal medulla, the midbrain torus semicircularis, and the optic tectum. Similarities in the structure of the anterior lateral line nerves and medullary organization between lampreys and several primitive jawed fishes indicate that the electroreceptive systems are homologous in these taxa. Thus electroreception was probably present in the earliest vertebrates ancestral to both agnathans and gnathostomes.
Cerebroventricular Propranolol Elevates Cerebrospinal Fluid Norepinephrine and Lowers Blood Pressure
Authors: Tackett Randall L. , Webb Jerry G. , Privitera Philip J.
Published: October 2006

Ventriculocisternal administration ofdl- andd-propranolol produced dose-dependent increases in cerebrospinal fluid norepinephrine and reductions in blood pressure. A highly significant correlation was found between the increase in norepinephrine and the hypotensive effect. The propranolol-induced hypotension was prevented by intracisternal phentolamine. These data indicate that the hypotensive effect of centrally administered propranolol results from a drug-induced release of norepinephrine, which stimulates central alpha receptors to lower arterial pressure.
Regeneration of Neurites on Long-Term Cultures of Sympathetic Neurons Deprived of Nerve Growth Factor
Authors: Campenot Robert B.
Published: October 2006

Sympathetic neurons from newborn rats, cultured for 1 month or longer in the virtual absence of nonneuronal cells, were capable of regenerating neurites after neuritotomy. Regeneration occurred even after nerve growth factor was withdrawn from the cultures, although it was much less extensive and appeared limited to a few days following neuritotomy. Even after 29 days of nerve growth factor deprivation, reintroduction of the protein prompted a resumption of neurite growth. Possible roles of both nerve growth factor-independent and -dependent components in adult nerve regeneration are discussed.
Intraventricular Calcitonin Inhibits Gastric Acid Secretion
Authors: Morley John E. , Levine Allen S. , Silvis Stephen E.
Published: October 2006

Parenteral and intracerebroventricular administration of calcitonin in rats resulted in the suppression of gastric acid secretion. This suppression also occurred in rats with insulin-induced hypoglycemia and after the administration of thyrotropin-releasing hormone. Intracerebroventricularly administered calcitonin was 1000 times more effective than parenterally administered calcitonin in suppressing gastric acid secretion. Calcitonin also inhibited the development of stress-induced ulcers in rats.
Detection of Circulating Metallothionein in Rats Injected with Zinc or Cadmium
Authors: Garvey Justine S. , Chang Chin C.
Published: October 2006

Circulating metallothionein was measured by radioimmunoassay over a 13-day period in male Sprague-Dawley rats that received a sequence of three intraperitoneal injections (at 3-day intervals) of either 5 milligrams of zinc or 0.8 milligrams of cadmium per kilogram of body weight. These amounts of zinc and cadmium produced metallothionein concentrations in the range of 2 to 5 nanograms per milliliter of serum (zinc) and 2 to 15 nanograms per milliliter of serum (cadmium). In control rats given saline injections over the same period the metallothionein concentration ranged from 1 to 3 nanograms per milliliter of serum.
Spatial Frequency Columns in Primary Visual Cortex
Authors: Tootell Roger B. , Silverman Martin S. , De Valois Russell L.
Published: October 2006

Using the activity-dependent 2-[
14
C]deoxy-D-glucose technique, we have demonstrated a columnar organization of spatial frequency-specific sensitivity in striate cortex. Cats viewing patterns containing a single spatial frequency presented at all orientations show columns of increased deoxyglucose uptake extending through all cortical layers. A control stimulus containing all spatial frequencies presented at all orientations produces no columnar density differences within the striate cortex.
Individual Hippocampal Mossy Fiber Distribution in Mice Correlates with Two-Way Avoidance Performance
Authors: Schwegler H. , Lipp H. P. , Van der Loos H. , Buselmaier W.
Published: October 2006

Mice systematically bred for randomization of their genotype show large individual differences when performing a two-way avoidance task (shuttle-box learning). Their behavioral scores correlate strongly (
r
= -0.80, P < .01) with the number of mossy fibers synapsing on basal dendrites of hippocampal pyramidal neurons, poor avoiders having relatively more such terminals. This confirms previous findings showing that rat and mouse strains known for genetically dependent poor avoidance learning have extended intra- and infrapyramidal mossy fiber projections.
Responses of Sheep to
Zygadenus gramineus
, "Death Camas"
Authors: McLaughlin Alvah R.
Published: October 2006

An extract of
Zygadenus gramineus,
"death camas," from which most of the resins had been removed was given intravenously to sheep prepared for recording blood-pressure and respiratory movements.

Following the intravenous injection of this extract there occurred a respiratory inhibition which in the case of the injection of larger amounts of the extract was followed by asphyxia-like rises of blood-pressure.

The graphic record of this asphyxial condition was practically duplicated by closing the tracheal cannula for a short time following the recovery of the animal from the effects of the plant extract.

Although, from a field standpoint, no satisfactory antidote has been found, it has been demonstrated that caffein sodio-benzoate possesses marked powers of stimulation for the respiratory center affected by the depressive substances found in
Zygadenus gramineus.
Comparison Between Irradiation of Diet and Supplemental Irradiation of Animals in Vitamin A and D Deficiency
Authors: Chidester F. E. , Eaton A. G. , Speicher N. K.
Published: October 2006

The stimulating effects of the Vitamin D thus supplied became quite apparent and lasted for 10 days, then began to subside. The animals in Lot 2 were allowed to exist on the Sherman No. 380 diet, with supplemental Vitamin D, in the form of irradiated ergosterol, but in Lot 1 the animals were also irradiated daily except Sundays, for 30 seconds, at a distance of 18 inches from a Macbeth carbon arc lamp.
Active Ion Transport in Dog Tongue: A Possible Role in Taste
Authors: DeSimone John A. , Heck Gerard L. , DeSimone Shirley K.
Published: October 2006

An in vitro preparation of the dorsal epithelium of the dog tongue actively transports ions, producing a transepithelial potential difference characteristic of the ions and their concentration. Hypertonic sodium chloride solutions generally cause increased potentials and short-circuit currents and reduced resistances when placed on the mucosal surface. This hypertonic flux is eliminated by ouabain and is not found in ventral lingual epithelia. When either sodium acetate or tetramethylammonium chloride is substituted for sodium chloride in the mucosal medium, the currents are diminished but their sum at a given concentration approximates that for sodium chloride at the same concentration. This result suggests a current composed of inward sodium ion movement and outward chloride ion movement. Actively regulated potentials and currents, whether generated in the taste buds or in supporting cells, may be important in both normal chemotransduction and in taste responses evoked by currents passing through the tongue.
Retina-Dependent Activation by Apomorphine of Metabolic Activity in the Superficial Layer of the Superior Colliculus
Authors: McCulloch James , Savaki Helen E. , McCulloch Mailis C. , Sokoloff Louis
Published: October 2006

Studies of the effects of the dopamine agonist apomorphine on local cerebral glucose utilization by means of the carbon-14-labeled deoxyglucose method demonstrate a dose-dependent metabolic activation in the superficial layer of the superior colliculus in the rat. Apomorphine stimulated glucose utilization in a number of other cerebral structures, but only the effect in the superficial layer of the superior colliculus depended on an intact retinal input. This effect was present with the animal in the light or in the dark, but was abolished by enucleation, which left the effects in other cerebral structures unimpaired. Activation of the superficial layer of the superior colliculus appears, therefore, to be secondary to an action of apomorphine on dopaminergic systems within the retina.
Electroreception in the Ratfish (
Hydrolagus colliei
)
Authors: Fields R. Douglas , Lange G. David
Published: October 2006

Behavioral and neurophysiological experiments and anatomical work indicate that the ampullar structures on the head of fish of the subclass Holocephali are sense organs responsive to weak electric fields and are functionally and structurally homologous to the ampullae of Lorenzini in elasmobranchs. It is concluded that, as in elasmobranchs, these organs are used to detect bioelectric and other natural electric phenomena in the environment.
Affective Discrimination of Stimuli That Cannot Be Recognized
Authors: Kunst-Wilson William Raft , Zajonc R. B
Published: October 2006

Animal and human subjects readily develop strong preferences for objects that have become familiar through repeated exposures. Experimental evidence is presented that these preferences can develop even when the exposures are so degraded that recognition is precluded.
Fluorescent Light Induces Malignant Transformation in Mouse Embryo Cell Cultures
Authors: Kennedy Ann R. , Ritter Mark A. , Little John B.
Published: October 2006

Fluorescent light induced a dose-dependent malignant transformation in mouse C3H10T½ cells. A plateau in the dose-response curve for transformation was correlated with that observed with ultraviolet light exposure. The similarity in the two dose-response patterns suggests that similar molecular processes may be involved in the induction of malignant transformation by the two types of radiation.
Alzheimer's Disease: X-Ray Spectrometric Evidence of Aluminum Accumulation in Neurofibrillary Tangle-Bearing Neurons
Authors: Perl Daniel P. , Brody Arnold R.
Published: October 2006

The elemental content of neurons of the hippocampus was studied by a combination of scanning electron microscopy and x-ray spectrometry in autopsy-derived brain tissue from three cases of senile dementia (Alzheimer type) and three nondemented elderly controls. Foci of aluminum were detected within the nuclear region of a high percentage of neurons containing neurofibrillary tangles from the cases of senile dementia as well as the elderly controls. The adjacent normal-appearing neurons from both groups of patients were virtually free of detectable aluminum. These findings suggest that the association of aluminum to Alzheimer's disease extends to the neuronal level.
Monte Carlo Simulation of Water Behavior Around the Dipeptide
N
-Acetylalanyl-
N
-Methylamide
Authors: Hagler A. T. , Osguthorpe D. J. , Robson B.
Published: October 2006

Applications of Monte Carlo and molecular dynamics computer simulation techniques indicate that they are potentially powerful tools for understanding biological systems at the molecular level. The Monte Carlo technique can be used to study the solvent structure around a small peptide and the effect of the aqueous environment on the conformational equilibria of the peptide.
Opioid and Nonopioid Mechanisms of Stress Analgesia
Authors: Lewis James W. , Cannon J. Timothy , Liebeskind John C.
Published: October 2006

Inescapable foot shock in rats caused profound analgesia that was antagonized by naloxone or dexamethasone when shock was delivered intermittently for 30 minutes, but not when it was delivered continuously for 3 minutes. Thus, depending only on its temporal characteristics, foot-shock stress appears to activate opioid or nonopioid analgesia mechanisms. Certain forms of stress may act as natural inputs to an endogenous opiate analgesia system.
The Fetal Sound Environment of Sheep
Authors: Armitage Sally E. , Baldwin B. A. , Vince Margaret A.
Published: October 2006

Hydrophones implanted inside the intact amniotic sac recorded sounds available to fetal lambs. Unlike recordings made from outside the intact amnion in human subjects, sounds produced at levels similar to normal conversation from outside the ewe were picked up without masking by maternal cardiovascular sounds. Noises from inside the mother were intermittent and linked to her activity.
Ethanol: Novel End Product of Vertebrate Anaerobic Metabolism
Authors: Shoubridge Eric A. , Hochachka P. W.
Published: October 2006

During periods of short-term experimental anoxia, the goldfish produces metabolic carbon dioxide and does not accumulate lactate to the extent expected. The goldfish has evolved a novel pathway of vertebrate anaerobic metabolism in which glucose carbon is metabolized to ethanol and excreted.
Long-Lasting Depletion of Striatal Dopamine by a Single Injection of Amphetamine in Iprindole-Treated Rats
Authors: Fuller Ray W. , Hemrick-Luecke Susan
Published: October 2006

A single injection of amphetamine given to rats treated concurrently with iprindole so that they could not metabolize the amphetamine bypara-hydroxylation resulted in a decrease in the concentration of striatal dopamine 1 week later. The decrease was antagonized by amfonelic acid, an inhibitor of uptake into dopamine neurons. The long-lasting depletion of cerebral dopamine by amphetamine may be analogous to the depletion of cerebral serotonin by halogenated derivatives of amphetamine.
Tumoricidal Response Induced by Cytosine Arabinoside After Plasma Perfusion Over Protein A
Authors: Terman David S. , Yamamoto Tsuyoshi , Tillquist Richard L. , Henry Joseph F. , Cook Gary L. , Silvers Abraham , Shearer William T.
Published: October 2006

In dogs with spontaneous mammary adenocarcinomas, a single nontoxic infusion of cytosine arabinoside after extracorporeal perfusion of plasma over immobilized protein A resulted in a necrotizing response rapid in onset and specific for tumorous tissue. Gross tumoricidal reactions 12 hours after this combined treatment exceeded the algebraic sum of responses to cytosine arabinoside and protein A perfusion treatments alone in the same dogs, implying a synergistic effect between the two. The magnitude, rapidity, and specificity of the tumoricidal response after the combined treatment suggests that it may be an effective chemoimmunotherapeutic approach to breast adenocarcinoma.
Superior Colliculus: Control of Eye Movements in Neonatal Kittens
Authors: Stein Barry E. , Clamann H. P. , Goldberg S. J.
Published: October 2006

Activation of the neonatal cat superior colliculus can produce organized eye movements before visual stimuli are capable of activating visual neurons in the colliculus. These findings are consistent with the hypothesis that eye movement development precedes, and is necessary for, visuomotor integration.
A New Irradiation Effect and Its Implications for the Disposal of High-Level Radioactive Waste
Authors: Hirsch E. H.
Published: October 2006

Materials containing alkali metals or alkaline earths are sensitized by bombardment with either ions, electrons, or photons to chemical attack by atmospheric moisture. The implications of this effect on the proposed immobilization and long-term storage of high-level nuclear waste in glass or similar materials is discussed.
Anxiety and Muscle Tension as Consequences of Caffeine Withdrawal
Authors: White Brent C. , Lincoln Cynthia A. , Pearce Nell W. , Reeb Robin , Vaida Chris
Published: October 2006

Regular consumers of caffeine had higher muscle tension after three or more hours of abstinence than low caffeine consumers. This difference was absent after double-blind administration of caffeine citrate or placebo. In a discriminative reaction time test, caffeine treatment improved performance. Among subjects receiving placebo, anxiety was highly correlated with prior caffeine use, suggesting that even a brief abstinence may produce anxiety in the regular user.
Potassium Chloride Versus Voltage Clamp Contractures in Ventricular Muscle
Authors: Morad M. , Reeck S. , Rao M.
Published: October 2006

In frog ventricle, developed tension was markedly larger in response to depolarization caused by a voltage clamp step than to depolarization induced by high concentrations of potassium chloride. Measurement of extracellular potassium activity at the surface and at the depth of muscle during the development of contractures showed that the diffusion of potassium is much slower than the spread of depolarization through the cross section of muscle. These two observations suggest that competition between the depolarizing and the negative inotropic effects of an increase in the extracellular potassium ion concentration may determine the time course and magnitude of contractile tension in heart muscle.
Endogenous Late Positive Component of the Evoked Potential in Cats Corresponding to P300 in Humans
Authors: Wilder M. Byron , Farley Glenn R. , Starr Arnold
Published: October 2006

A long-latency component of the averaged evoked potential recorded from cats was present only when the evoking stimulus was relevant to the task. The amplitude of this component varied inversely with stimulus probability and was independent of stimulus modality.
A Regulatory Locus for Mouse β-Glucuronidase Induction,
Gur
, Controls Messenger RNA Activity
Authors: Paigen Kenneth , Labarca Cesar , Watson Gordon
Published: October 2006

A regulatory locus in a higher organism has been shown to control a specific messenger RNA activity. The
Gur
locus in mice regulates the production of kidney β-glucuronidase messenger RNA activity after induction of the β-glucuronidase structural gene, Gus, by testosterone. β-Glucuronidase messenger RNA was assayed by its ability to direct the synthesis of catalytically active murine β-glucuronidase in
Xenopus
oocytes.
Inhibition of Rev-Mediated HIV-1 Expression by an RNA Binding Protein Encoded by the Interferon-Inducible 9-27 Gene
Authors: Constantoulakis Pantelis , Campbell Mel , Felber Barbara K. , Nasioulas Georgios , Afonina Elena , Pavlakis George N.
Published: October 2006

Interferon inhibits expression of human immunodeficiency virus type-1 (HIV-1) through unknown mechanisms. A gene inducible by interferon-α (IFN-α) and interferon-γ (IFN-γ) was isolated by screening of a human complementary DNA library for proteins binding to the Rev-responsive element (RRE) of HIV-1. The product of this gene, RBP9-27, was shown to bind RNA in vitro and to inhibit HIV-1 expression after transfection into human cells. RBP9-27 primarily inhibited Rev-dependent posttranscriptional steps of viral gene expression. Thus, RBP9-27 is a cellular factor that antagonizes Rev function. These results suggest an interferon-induced antiviral mechanism operating through the induction of RNA binding proteins such as RBP9-27. Elucidation of RBP9-27 function may lead to a better understanding of the mechanism of interferon action during HIV-1 infection.
Suppression of Chronic Allergic Encephalomyelitis: Relevance to Multiple Sclerosis
Authors: Raine Cedric S. , Traugott Ute , Stone Sanford H.
Published: October 2006

The expression of chronic relapsing experimental allergic encephalomyelitis in strain 13 guinea pigs was suppressed with a single series of injections of myelin basic protein in incomplete Freund's adjuvant. The suppression appeared permanent, and subsequent rechallenge with central nervous system antigen failed to elicit exacerbations.
Structural Domains of Transfer RNA Molecules
Authors: Quigley Gary J. , Rich Alexander
Published: October 2006

In this article, we have described various detailed features of the conformation of yeast tRNA
Phe
revealed by recent refinement analysis of x-ray diffraction data at 2.5 A resolution. The gross features of the molecule observed in the unrefined version have been largely confirmed and a number of new features found. The unique role of the ribose 2′ hydroxyl groups in maintaining a series of nonhelical conformations in this RNA molecule has become apparent. Many of these features are a direct consequence of the geometry of the ribose phosphate backbone of RNA molecules, and these may also be found in structured regions of other RNA species as well. Special attention has been directed toward two conformational motifs revealed by this analysis. These include the striking similarity between the TψC and anticodon hairpin turns in the polynucleotide chain, which are stabilized by the participation of uridine in the U turn. In addition, there is frequent occurrence of an arch conformation in the polynucleotide chian which is stabilized by hydrogen bonds from 2′ hydroxyl residues to phosphate groups across the base of the arch. The importance of the 2′ hydroxyl interactions in defining tertiary structure is illustrated by the fact that, in the nonhelical regions, almost half of the ribose residues are involved in O2′ hydrogen-bonding interactions which stabilize the conformation of the molecule.
Reduction in Size of the Myotonic Dystrophy Trinucleotide Repeat Mutation During Transmission
Authors: O'Hoy Kim L. , Tsilfidis Catherine , Mahadevan Mani S. , Neville Catherine E. , Barceló Juana , Hunter Alasdair G. W. , Korneluk Robert G.
Published: October 2006

Myotonic dystrophy (DM) is an autosomal-dominant disorder that affects 1 in 8000 individuals. Amplification of an unstable trinucleotide CTG repeat, located within the 3′ untranslated region of a gene, correlates with a more severe DM phenotype. In three cases, the number of CTG repeats was reduced during the transmission of the DM allele; in one of these cases, the number was reduced to within the normal range and correlated at least with a delay in the onset of clinical signs of DM. Haplotype data of six polymorphic markers in the DM gene region indicate that, in this latter case, two stretches of the affected chromosome had been exchanged with that region of the wild-type chromosome.
Metal Compounds in Therapy and Diagnosis
Authors: Abrams Michael J. , Murrer Barry A.
Published: October 2006

There is increasing interest in the use of metal-containing compounds in medicine. This review describes several therapeutic applications, such as the use of platinum complexes in cancer chemotherapy, gold compounds in the treatment of arthritis, gallium in hypercalcemia, bismuth in anti-ulcer medication, and sodium nitroprusside in hypertension. The use of metal radionuclides in diagnosis and radiotherapy and the role of paramagnetic metal complexes as contrast agents in magnetic resonance imaging are also discussed.
Localization of an Exchangeable GTP BZinding Site at the Plus End of Microtubules
Authors: Mitchison T. J.
Published: October 2006

Microtubule polarity arises from the head-to-tail orientation of α-β tubulin heterodimers in the microtubule lattice. The identity of the polypeptide at each end of the microtubule is unknown, but structural models predict that the β-tubulin end contains an exchangeable guanosine triphosphate (GTP) binding site. When GTP-coated fluorescent beads were incubated with microtubules, they bound specifically to plus ends, suggesting that tubulin is oriented in microtubules with β-tubulin toward the plus end.
Commissural and Cortico-Cortical "Columns" in the Somatic Sensory Cortex of Primates
Authors: Jones E. G. , Burton H. , Porter R.
Published: October 2006

Anatomical experiments demonstrate that commissural and cortico-cortical fibers arising and terminating in the somatic sensory cortex of monkeys terminate in layers I through IV in a mosaic of precisely ordered vertical bands. The cells of origin of these fibers, found predominantly in layer III, are also arranged in vertical aggregations.
Hepatocellular Transplantation for Metabolic Deficiencies: Decrease of Plasma Bilirubin in Gunn Rats
Authors: Matas Arthur J. , Sutherland David E. R. , Steffes Michael W. , Mauer S. Michael , Sowe Ann , Simmons Richard L. , Najarian John S.
Published: October 2006

A sustained decrease of plasma bilirubin concentrations occurred in homozygous recessive Gunn rats lacking the enzyme uridine diphosphate glucuronyltransferase following infusion into the portal vein of hepatocytes from heterozygous nonjaundiced Gunn rats possessing the enzyme. Transplantation of cells capable of continuous enzyme production could be an effective mode of therapy for congenital enzyme deficiency diseases.
Thyrotropin Releasing Hormone: Development of Inactivation System During Maturation of the Rat
Authors: Neary Joseph T. , Kieffer J. David , Federico Panfilo , Mover H. , Maloof F. , Soodak M.
Published: October 2006

Whereas thyrotropin releasing hormone is rapidly and extensively degraded by plasma of adult rats, no appreciable loss of biological or immunological activity is caused by plasma from rats 4 or 16 days old. The plasma of neonatal rats does not appear to contain an inhibitor of thyrotropin releasing hormone peptidase or a peptidase with altered substrate affinity. The development of an active peptidase in rat plasma suggests a physiological role for inactivation of thyrotropin releasing hormone.
Molecular Dynamics Simulations of a Lipid Bilayer and of Hexadecane: An Investigation of Membrane Fluidity
Authors: Venable Richard M. , Zhang Yuhong , Hardy Barry J. , Pastor Richard W.
Published: October 2006

Molecular dynamics simulations of a fluid-phase dipalmitoyl phosphatidylcholine lipid bilayer in water and of neat hexadecane are reported and compared with nuclear magnetic resonance spin-lattice relaxation and quasi-elastic neutron scattering data. On the 100-picosecond time scale of the present simulations, there is effectively no difference in the reorientational dynamics of the carbons in the membrane interior and in pure hexadecane. Given that the calculated fast reorientational correlation times and the "microscopic" lateral diffusion of the lipids show excellent agreement with the experimental results, it is concluded that the apparently high viscosity of the membrane is more closely related to molecular interactions on the surface rather than in the interior.
Resistance of Mice Deficient in IL-4 to Retrovirus-Induced Immunodeficiency Syndrome (MAIDS)
Authors: Kanagawa Osami , Vaupel Barbara A. , Gayama Shinyo , Koehler Georges , Kopf Manfred
Published: October 2006

The murine acquired immunodeficiency syndrome (MAIDS) is induced by a defective murine leukemia virus and has many symptoms similar to those found in patients infected with the human immunodeficiency virus. The presence of both B cells and CD4
+
T cells is critical for the development of the disease. Furthermore, a Th2 cytokine response dominates during the progression of the disease. When interleukin-4 (IL-4)-deficient mice that are defective in Th2 cytokine responses were infected, there was no lethality, and the development of the T cell abnormalities associated with MAIDS was delayed. These data suggest that IL-4 or a Th2 response is involved in the development of retrovirus-induced immunodeficiency in mice.
Gene Dose Effect: Regional Mapping of Human Nucleoside Phosphorylase on Chromosome 14
Authors: George Donna L. , Francke Uta
Published: October 2006

Quantitative analyses of erythrocyte nucleoside phosphorylase in four unrelated cases of partial trisomy 14 indicate that the structural gene for this enzyme maps in the chromosome region 14q11→14q21.
Origin Recognition Complex (ORC) in Transcriptional Silencing and DNA Replication in
S. cerevisiae
Authors: Foss Margit , McNally Francis J. , Laurenson Patricia , Rine Jasper
Published: October 2006

In
Saccharomyces cerevisiae
, the
HMR-E
silencer blocks site-specific interactions between proteins and their recognition sequences in the vicinity of the silencer. Silencer function is correlated with the firing of an origin of replication at
HMR-E
. An essential gene with a role in transcriptional silencing was identified by means of a screen for mutations affecting expression of
HMR
. This gene, known as
ORC2
, was shown to encode a component of the origin recognition complex that binds yeast origins of replication. A temperature-sensitive mutation in
ORC2
disrupted silencing in cells grown at the permissive temperature. At the restrictive temperature, the
orc2-1
mutation caused cell cycle arrest at a point in the cell cycle indicative of blocks in DNA replication. The
orc2-1
mutation also resulted in the enhanced mitotic loss of a plasmid, suggestive of a defect in replication. These results provide strong evidence for an in vivo role of ORC in both chromosomal replication and silencing, and provide a link between the mechanism of silencing and DNA replication.
Linearity of Summation of Synaptic Potentials Underlying Direction Selectivity in Simple Cells of the Cat Visual Cortex
Authors: Jagadeesh Bharathi , Wheat Heidi S. , Ferster David
Published: October 2006

Intracellular recordings from simple cells of the cat visual cortex were used to test linear models for the generation of selectivity for the direction of visual motion. Direction selectivity has been thought to arise in part from nonlinear processes, as suggested by previous experiments that were based on extracellular recordings of action potentials. In intracellular recordings, however, the fluctuations in membrane potential evoked by moving stimuli were accurately predicted by the linear summation of responses to stationary stimuli. Nonlinear mechanisms were not required.
Mesenchyme-Dependent Morphogenesis and Epithelium-Specific Cytodifferentiation in Mouse Mammary Gland
Authors: Sakakura Teruyo , Nishizuka Yasuaki , Dawe Clyde J.
Published: October 2006

Isografts of heterotypic recombinants of embryonic mammary epithelium with salivary mesenchyme undergo development morphogenetically resembling that of salivary gland. However, cytodifferentiation of the epithelium is like that of mammary gland. In lactating hosts these isografts respond to endogenous hormonal stimulation and synthesize a milk protein, α-lactalbumin.
Thymic Muscle Cells Bear Acetylcholine Receptors: Possible Relation to Myasthenia Gravis
Authors: Kao Ing , Drachman Daniel B.
Published: October 2006

Culture of dissociated thymus from rats and humans yielded cells identical to skeletal muscle with respect to morphology, contractility, electrophysiological properties, and the presence of acetylcholine receptors. These cells, strategically located in the thymus, may play a role in initiation of the autoimmune response against acetylcholine receptors, which is characteristic of myasthenia gravis.
Synthetic Galactocerebrosides Evoke Myelination-Inhibiting Antibodies
Authors: Hruby Sarka , Alvord Ellsworth C. , Seil Fredrick J.
Published: October 2006

Synthetic galactodihydrocerebrosides with widely different fatty acid components can evoke myelination-inhibiting antibodies in rabbits. Whether these are the only such haptens involved in experimental immunizations of other species or in spontaneous human diseases is not yet known.
How Fish Power Swimming
Authors: Rome Lawrence C. , Swank Douglas , Corda David
Published: October 2006

It is thought that fish generate the power needed for steady swimming with their anterior musculature, whereas the posterior musculature only transmits forces to the tail and does negative work. Isolated red muscle bundles driven through the length changes and stimulation pattern that muscles normally undergo during steady swimming showed the opposite pattern. Most of the power for swimming came from muscle in the posterior region of the fish, and relatively little came from the anterior musculature. In addition, the contractile properties of the muscle along the length of the fish are significantly adapted to enhance power generation.
DNA Melting on Yeast RNA Polymerase II Promoters
Authors: Giardina Charles , Lis John T.
Published: October 2006

Transcription-dependent DNA melting on the yeast
GAL1
and
GAL10
promoters was found to be more closely correlated with the TATA box than the transcription start site. On both these genes, melting begins about 20 base pairs downstream of the TATA box. Physical and genetic analyses suggest that RNA polymerase II associates with this region. Thus, the distance between promoter melting and the TATA box in yeast may be similar to that in higher eukaryotes, even though transcription initiates in a region about 10 to 90 base pairs farther downstream in yeast.
Public Health Hazards from Electricity-Producing Plants
Authors: Neyman Jerzy
Published: October 2006

When a new electricity-producing plant is to be built in a given locality it is natural to take into account the public health consequences of the normal operation of each type of plant contemplated. Here, the fossil-burning plants and nuclear facilities come under consideration. I have attempted to show that, in spite of the many important studies performed, there is currently no reliable methodology to estimate how many more cancer cases, and how many more heart attacks and other diseases have to be anticipated as a consequence of the normal operation of this or that type of electric generator. In part, this is because the currently available estimates of radiation effects on humans are based on extrapolations from studies of two kinds. Those of one kind may be exemplified by studies of atomic bomb casualties in Hiroshima and Nagasaki. The other kind are laboratory experiments with lower animals, frequently mice. The unreliability of both kinds of extrapolations is connected with the following circumstances: (i) The omnipresent troublesome phenomenon of competing risks. (ii) The dependence of health effects of a given noxious agent on the preexisting local pollution. (iii) The dependence of health effects not only on the "dose" of an agent, but also on the rate at which the agent is administered. (iv) The noted difficulties of making extrapolations from one mammal to another.

Our obtaining reliable estimates of the public health effects of extra pollution from new industrial plants would seem to depend on a large multipollutant and multilocality epidemiological study being conducted—one requiring the cooperative effort of several governmental agencies. However, a much easier study of certain developments in the vicinity of Rocky Flats, Colorado, might provide important direct information on health phenomena as they occur in real life.
Altered Yolk Structure and Reduced Hatchability of Eggs from Birds Fed Single Doses of Petroleum Oils
Authors: Grau C. R. , Roudybush T. , Dobbs J. , Wathen J.
Published: October 2006

Yolk deposited by Japanese quail was abnormal for 24 hours after the oral administration of a single capsule containing 200 milligrams of bunker C oil. Both the structure and the staining properties of the yolk were affected. Fewer eggs were laid during the 4 days after dosing, compared to controls, and hatchability was drastically reduced. Hatchability returned to normal in 4 days. Three other reference oils also affected yolk structure. Canada geese given 2 grams and chickens given 500 milligrams of bunker C oil produced eggs with abnormal yolk rings.
A Role for the Transcription Factors Mbp1 and Swi4 in Progression from G1 to S Phase
Authors: Koch Christian , Moll Thomas , Neuberg Manfred , Ahorn Horst , Nasmyth Kim
Published: October 2006

In budding yeast genes that encode G1 cyclins and proteins involved in DNA synthesis are transcriptionally activated in late G1. A transcription factor, called SBF, is composed of Swi4 and Swi6 proteins and activates transcription of G1 cyclin genes. A different, but related, complex called MBF binds to MCB elements (Mlu I cell cycle box) found in the promoter of most DNA synthesis genes. MBF contains Swi6 and a 120-kilodalton protein (p120). MBF was purified and the gene encoding p120 (termed
MBP1
) was cloned. A deletion of
MBP1
was not lethal but led to deregulated expression of DNA synthesis genes, indicating a direct regulatory role for MBF in MCB-driven transcription. Mbp1 is related to Swi4. Strains deleted for both
MBP1
and
SWI4
were inviable, demonstrating that transcriptional activation by MBF and SBF has an important role in the transition from G1 to S phase.
Binding of the Ras Activator Son of Sevenless to Insulin Receptor Substrate-1 Signaling Complexes
Authors: Baltensperger Kurt , Kozma Lynn M. , Cherniack Andrew D. , Klarlund Jes K. , Chawla Anil , Banerjee Utpal , Czech Michael P.
Published: October 2006

Signal transmission by insulin involves tyrosine phosphorylation of a major insulin receptor substrate (IRS-1) and exchange of Ras-bound guanosine diphosphate for guanosine triphosphate. Proteins containing Src homology 2 and 3 (SH2 and SH3) domains, such as the p85 regulatory subunit of phosphatidylinositol-3 kinase and growth factor receptor-bound protein 2 (GRB2), bind tyrosine phosphate sites on IRS-1 through their SH2 regions. Such complexes in COS cells were found to contain the heterologously expressed putative guanine nucleotide exchange factor encoded by the
Drosophila
son of sevenless
gene (dSos). Thus, GRB2, p85, or other proteins with SH2-SH3 adapter sequences may link Sos proteins to IRS-1 signaling complexes as part of the mechanism by which insulin activates Ras.