bluuebunny/crossref_metadata_2025 huggingface dataset:
Aural Representation in the Doppler-Shifted-CF Processing Area of the Auditory Cortex of the Mustache Bat
Authors: Manabe Toshiki , Suga Nobuo , Ostwald Joachim
Published: October 2006

In the mustache bat (
Pteronotus parnellii rubiginosus
) the frequency and amplitude of an acoustic signal are represented in the coordinates parallel to the surface of the Doppler-shifted-CF (constant frequency) processing area of the primary auditory cortex. In this area all cortical neurons studied were excited by contralateral stimuli, and almost all of them were either excited or inhibited by ipsilateral stimuli. These are called E-E (ipsilateral and contralateral excitatory) and I-E (ipsilateral inhibitory and contralateral excitatory) neurons, respectively. The I-E neurons are directionally sensitive, while the E-E neurons are not. The E-E neurons are equally sensitive to echoes between 30° contralateral and 30° ipsilateral. Of the electrode penetrations orthogonal to the Doppler-shifted-CF processing area, 57 percent were characterized by either E-E or I-E neurons. Thus, there are at least two types of binaural columns: E-E columns, mainly located in a ventral part of the Doppler-shifted-CF processing area, where neurons are tuned to weak echoes; and IE columns, mainly distributed in a dorsal part, where neurons are tuned to moderate to intense echoes. Therefore, neurons tuned to weaker echoes integrate or even multiply faint signals from both ears for effective detection of a distant small target, while neurons tuned to moderate to intense echoes are suited for processing directional information and are stimulated when a bat approaches a target at short range. The Doppler-shifted-CF processing area may be considered to consist of two functional subdivisions.
Cellular Oncogenes and Multistep Carcinogenesis
Authors: Land Hartmut , Parada Luis F. , Weinberg Robert A.
Published: October 2006

Two dozen cellular proto-oncogenes have been discovered to date through the study of retroviruses and the use of gene transfer. They form a structurally and functionally heterogeneous group. At least five distinct mechanisms are responsible for their conversion to active oncogenes. Recent work provides experimental strategies by which many of these oncogenes, as well as oncogenes of DNA tumor viruses, may be placed into functional categories. These procedures may lead to definition of a small number of common pathways through which the various oncogenes act to transform cells.
Insulin Receptor Phosphorylation May Not Be a Prerequisite for Acute Insulin Action
Authors: Simpson Ian A. , Hedo José A.
Published: October 2006

An antiserum to the insulin receptor mimicked insulin's acute actions on glucose transport, phosphorylation of integral membrane proteins, and internalization of the insulin receptor in isolated rat adipose cells. These insulinomimetic actions of the antiserum occurred without the equivalent increase in phosphorylation of the β subunit of the insulin receptor observed with insulin. Thus, a role of receptor phosphorylation in acute insulin action is now questioned.
Suppression of Prolactin in Pigs by
Escherichia coli
Endotoxin
Authors: Smith Bradford B. , Wagner W. C.
Published: October 2006

An endotoxin produced by
Escherichia coli
caused a decrease in prolactin concentrations in the plasma of sows when given at low dosages 2 days postpartum. Five to tenfold increases occurred in the plasma cortisol concentrations. Piglet growth, used as an indicator of milk secretion by the sows, was significantly depressed after the endotoxin administration. Some cases of lactation failure in the periparturient sow may thus be due to endotoxins suppressing prolactin concentrations. This appears to be the first report of a bacterial endotoxin having an effect on prolactin in any species.
Enzymatic Approach to Syntheses of Unnatural Beta-Lactams
Authors: Wolfe Saul , Demain Arnold L. , Jensen Susan E. , Westlake D. W. S.
Published: October 2006

Four enzymes associated with the transformation of the peptide δ-(L-α-aminoadipyl)-L-cysteinyl-D-valine (ACV) into the beta-lactam antibiotic desacetylcephalosporin C have been isolated from the prokaryotic organism
Streptomyces clavuligerus
and immobilized. Appropriate choice of the cofactors allows continuous and quantitative conversion of the peptide into either penicillins or cephalosporins at room temperature. The overall process includes four oxidations, two ring closures, and one epimerization. In contrast, cell-free transformations with the eukaryotic organism
Cephalosporium acremonium
do not proceed beyond the oxidation level of penicillin. The amino acids of the natural peptide ACV can be altered by chemical means; several of the resulting peptides are converted into novel antibiotics by the enzymes of
Streptomyces clavuligerus
.
Stable Antibody-Producing Murine Hybridomas
Authors: Taggart R. Thomas , Samloff I. Michael
Published: October 2006

A method is described for obtaining antibody-producing hybridomas that are preferentially retained in cultures of fused mouse spleen and myeloma cells. Hybridomas are produced by fusing mouse myeloma cells that are deficient in adenosine phosphoribosyltransferase (APRT) with mouse spleen cells containing Robertsonian 8.12 translocation chromosomes. The cell fusion mixtures are exposed to a culture medium that can be utilized only by APRT-positive cells, which results in the elimination of both unfused APRT-deficient myeloma cells and non-antibody-producing APRT-deficient hybridomas that arise by segregation of the 8.12 translocation chromosomes containing the APRT genes and the active heavy chain immunoglobulin gene.
Murine I-Aβ Chain Polymorphism: Nucleotide Sequences of Three Allelic I-Aβ Genes
Authors: Choi Edmund , McIntyre Katherine , Germain Ronald N. , Seidman J. G.
Published: October 2006

The polymorphism of immune response genes plays a critical role in determining the immune capabilities of a particular individual. The molecular nature of this polymorphism was studied by examining the structure of the coding portions of three alleles of the I-Aβ chain gene, an immune response gene whose protein product constitutes a subunit of the I-A molecule. Comparison of the I-Aβ chains encoded by these alleles revealed an amino acid sequence divergence of 5 to 8 percent. The differences were found to be a series of short alterations clustered in the amino terminal half of the polypeptide.
Supercritical Fluid Chromatography
Authors: Gere Dennis R.
Published: October 2006

Chromatographic separations with a supercritical fluid as the mobile phase were suggested more than 20 years ago. Availability of commercial hardware makes this technique more widely usable today. Many separations by this method are now carried out with supercritical carbon dioxide as the mobile phase and packed liquid-chromatography columns as the stationary phase. Although carbon dioxide has many practical advantages, including its near-ambient critical temperature and minimal interference with spectrometric detection, the use of other supercritical fluids or addition of modifiers to carbon dioxide may extend the applications of this technique. Some mixtures that are difficult to analyze by other chromatographic methods may be susceptible to separation by supercritical fluid chromatography. Mixtures that have been separated with supercritical carbon dioxide include resin acids with the empirical formula C
20
H
30
O
2
and ubiquinones from bacterial cell wall extracts of
Legionella pneumophila
.
The Interleukin-2 T-Cell System: A New Cell Growth Model
Authors: Cantrell Doreen A. , Smith Kendall A.
Published: October 2006

Synchronized interleukin-2 receptor-positive T cells, homogeneous immunoaffinity-purified interleukin-2, and a monoclonal antibody to interleukin-2 receptors were used to show that only three factors are critical for T-cell cycle progression: interleukin-2 concentration, interleukin-2 receptor density, and the duration of the interleukin-2 receptor interaction. Since the proliferative characteristics of T cells are identical to those of both prokaryotic and all other eukaryotic cells, these findings provide a new model that accounts fully for the variables that determine cell cycle progression.
Oncogene-Induced Transformation of C3H 10T1/2 Cells Is Enhanced by Tumor Promoters
Authors: Hsiao W.-L. W. , Gattoni-Celli S. , Weinstein I. B.
Published: October 2006

The tumor promoters 12-
O
-tetradecanoyl-phorbol-13-acetate and teleocidin markedly enhanced the transformation of C3H 10T1/2 mouse fibroblasts when these cells were transfected with the cloned human bladder cancer c-
ras
H
oncogene. Transfection studies with the drug resistance marker
gpt
and time course studies indicate that this enhancement is not simply an effect on the process of DNA transfection. These findings, together with parallel studies with NIH 3T3 fibroblasts, also indicate that the competence of animal cells for DNA transfection is a function of the recipient cell line, the transfected marker, and the growth conditions. Our findings suggest that during multistage carcinogenesis tumor promoters may complement the function of activated cellular oncogenes.
Rifampicin Inhibition of Protein Synthesis in Mammalian Cells
Authors: Buss W. C. , Morgan Robert , Guttmann John , Barela Thomas , Stalter Kenneth
Published: October 2006

Rifampicin produces a dose-dependent decrease in protein synthesis in rat thymocytes. At concentrations up to 200 micrograms per milliliter, rifampicin does not alter rat thymic transcription. Rifampicin causes a direct inhibition of protein synthesis in rat thymic and hepatic microsomes, and in cadaveric human hepatic microsomes. Protein synthesis inhibition could explain the toxicity of rifampicin in man.
Profits Derived from Segregating College Students on the Basis of Ability
Authors: Miller H. W.
Published: October 2006

(1) Under the above scheme of segregation about twenty per cent. of freshman engineering students were classed as "high" and another twenty per cent. as "low."
Striatal Nondopaminergic Neurons: Possible Involvement in Feeding and Drinking Behavior
Authors: Pettibone Douglas J. , Kaufman Nathan , Scally Michael C. , Meyer Edwin , Ulus Ismael , Lytle Loy D.
Published: October 2006

Intracaudate injections of kainic acid destroy striatal neurons containing acetylcholine and γ-aminobutyric acid but leave dopaminergic nerve terminals in this brain region intact. Rats injected with the drug are aphagic and adipsic, and have other behavioral abnormalities strikingly similar to those seen in animals with lesions in the dopaminergic nigrostriatal bundle.
Avian Pancreatic Polypeptide Phase Shifts Hamster Circadian Rhythms When Microinjected into the Suprachiasmatic Region
Authors: Albers H. Elliott , Ferris Craig F. , Leeman Susan E. , Goldman Bruce D.
Published: October 2006

The suprachiasmatic nucleus has been identified tentatively as a circadian pacemaker. To examine the functional role of peptides found within suprachiasmatic neurons, avian pancreatic polypeptide and vasopressin were microinjected into the suprachiasmatic region. Avian pancreatic polypeptide, but not vasopressin, shifted the phase of the wheelrunning rhythm as a function of the time of its injection within the circadian cycle. Avian pancreatic polypeptide or a similar peptide may be one component of the neurochemical processes underlying entrainment to the light-dark cycle.
Neurophysin Biosynthesis: Conversion of a Putative Precursor During Axonal Transport
Authors: Gainer Harold , Sarne Yosef , Brownstein Michael J.
Published: October 2006

[
35
S]Cysteine injected adjacent to the supraoptic nucleus of the rat is rapidly incorporated into a 20,000-dalton protein that, in time, is converted to a 12,000-dalton labeled protein, neurophysin. This putative precursor of neurophysin appears to be synthesized in the supraoptic nucleus and transformed to neurophysin and related peptides during axonal transport to the neurohypophysis.
RCapillaries: Basement Membrane Thickening by Galactosemia Prevented with Aldose Reductase Inhibitor
Authors: Robison W. Gerald , Kador Peter F. , Kinoshita Jin H.
Published: October 2006

A twofold thickening of capillary basement membranes of rat retinas resulting from dietary galactose was prevented by sorbinil, an inhibitor of aldose reductase. Since the basement membrane thickening was ultrastructurally similar to that typical of diabetic retinopathy, it may indicate changes in vessel permeability and susceptibility to hemorrhage. Galactosemic rats should be useful models for studying basement membrane-related complications of diabetes and for examining the potential biochemical regulation of basement membrane synthesis by aldose reductase inhibitors.
Corollary Discharge Provides Accurate Eye Position Information to the Oculomotor System
Authors: Guthrie Barton L. , Porter John D. , Sparks David L.
Published: October 2006

The saccadic system accurately compensates for perturbations of eye position produced by microstimulation of the superior colliculus. This requires that information about the stimulation-induced change in eye position be provided by an extraretinal source—either proprioceptive endings in extraocular muscles or a centrally generated corollary discharge. It is shown that compensation remains intact after elimination of extraocular muscle proprioception, demonstrating that corollary discharge provides accurate eye position information.
Axonal Proteins of Presynaptic Neurons During Synaptogenesis
Authors: Sonderegger Peter , Fishman Mark C. , Bokoum Madina , Bauer Hans C. , Nelson Phillip G.
Published: October 2006

Changes occur in the synthesis and axonal transport of neuronal proteins in dorsal-root ganglia axons as a result of contact with cells from the spinal cord during synapse formation. Dorsal-root ganglia cells were cultured in a compartmental cell culture system that allows separate access to neuronal cell bodies and their axons. When cells from the ventral spinal cord were cultured with the dorsal-root ganglia axons, synapses were established within a few days. Metabolic labeling and two-dimensional electrophoresis revealed that four of more than 300 axonal proteins had changed in their expression by the time synapses were established. The highly selective nature of these changes suggests that the proteins involved may be important in the processes of axon growth and synapse formation and their regulation by the regional environment.
Modulation of the Metastatic Capability in B16 Melanoma by Cell Shape
Authors: Raz Avraham , Ben-Ze'ev Avri
Published: October 2006

The lung colonization of B16-F1 cells grown in flat and spherical configurations was studied. Cells cultivated in vitro as spheroids on a nonadhesive substrate expressed in a reversible fashion a marked increase in their propensity to establish metastases. The altered metastatic capability was accompanied by a reversible reduction in the accessibility of cell surface proteins to external iodination and by a dramatic decrease in the synthesis of vimentin.
Detection of Intermodal Numerical Correspondences by Human Infants
Authors: Starkey Prentice , Spelke Elizabeth S. , Gelman Rochel
Published: October 2006

Infants prefer to look at an array of objects that corresponds in number to a sequence of sounds. In doing so, infants disregard the modality (visual or auditory) and type (object or event) of items presented. This finding indicates that infants possess a mechanism that enables them to obtain information about number.
The Use of Hypnosis to Enhance Recall
Authors: Dywan Jane , Bowers Kenneth
Published: October 2006

The forensic use of hypnosis is increasing. A hypermnesic procedure was used in an experiment that calls this practice into question. Subjects tried for a week to recall 60 previously presented pictures. They were then either hypnotized or not and encouraged to recall even more pictures. Most of the newly recalled material was incorrect, especially for highly hypnotizable subjects in the hypnosis condition. Such errors in recall can have profound implications for forensic investigations.
Capillary Zone Electrophoresis
Authors: Jorgenson James W. , Lukacs Krynn DeArman
Published: October 2006

Zone electrophoresis in open tubular capillaries is a useful approach to high-resolution separations of charged substances. Efficient heat transfer from small diameter capillaries permits application of unusually high voltages, which promote more effective separations and increase the speed of analyses. A sample injection technique and on-line zone detection create an instrumental format for zone electrophoresis. The basic theory, system parameters, and preliminary results are described.
Is Binocular Vision Always Monocular?
Authors: Blake Randolph , Camisa John
Published: October 2006

Visual sensitivity of one eye was determined under binocular stimulus conditions yielding apparent fusion, stereopsis, monocular dominance, and monocular suppression. Marked losses in sensitivity accompanied monocular suppression but were not evident during stable single vision. The results are inconsistent with the hypothesis that suppression alone mediates binocular single vision.
Drug History Modifies the Behavioral Effects of Pentobarbital
Authors: Glowa John R. , Barrett James E.
Published: October 2006

Behavior of squirrel monkeys, maintained by the termination of stimuli associated with electric shock, was suppressed by response-dependent shock delivery. The effects of pentobarbital on this behavior depended on whether monkeys had previously received morphine. In monkeys without experience with drugs, pentobarbital increased responding. In monkeys with recent experience with morphine, however, pentobarbital resulted in a smaller increase or decrease in responding. The rate-decreasing effects of pentobarbital after a history of morphine administration could be reversed by the administration of
d
-amphetamine. These findings suggest that the behavioral effects of abused drugs may depend on previous experience with other drugs, even when those drugs are from a different pharmacological class.
Protein Sequence Analysis: Automated Microsequencing
Authors: Hunkapiller Michael W. , Hood Leroy E.
Published: October 2006

The automated microsequencing of proteins can now be carried out at the 5- to 10-picomoles (submicrogram) level on polypeptides obtained directly from one- and two-dimensional gel electrophoresis. The techniques are applicable to polypeptides ranging in size from small peptides (less than 10 residues) to large proteins (more than 1000 residues).
A New Type D Retrovirus Isolated from Macaques with an Immunodeficiency Syndrome
Authors: Daniel Muthiah D. , King Norval W. , Letvin Norman L. , Hunt Ronald D. , Sehgal Prabhat K. , Desrosiers Ronald C.
Published: October 2006

Macaque monkeys with the recently described acquired immunodeficiency syndrome show a marked defect in T-lymphocyte function and die with opportunistic infections and lymphoproliferative abnormalities. In the study described here a new type D retrovirus was isolated from two
Macaca cyclopis
with this syndrome. This virus is related to, but distinct from, Mason-Pfizer monkey virus, a type D retrovirus previously isolated from a mammary tumor of a rhesus monkey (
Macaca mulatta
).
Haploid Expression of a Mouse Testis α-Tubulin Gene
Authors: Distel Robert J. , Kleene Kenneth C. , Hecht Norman B.
Published: October 2006

A complementary DNA clone for an α-tubulin has been isolated from a mouse testis complementary DNA library. The untranslated 3′ end of this complementary DNA is homologous to two RNA transcripts present in postmeiotic cells of the testis but absent from meiotic cells and from several tissues including brain. The temporal expression of this α-tubulin complementary DNA provides evidence for the haploid expression of a mammalian structural gene.
Directional Specificity in the Regeneration of Lamprey Spinal Axons
Authors: Yin H. S. , Mackler S. A. , Selzer M. E.
Published: October 2006

After spinal transection in ammocoetes (lamprey larvae) 4 to 5 years old, functional recovery is accompanied by a limited regeneration in which axons grow as far as 5 millimeters beyond the scar. In axotomized giant interneurons labeled intracellularly with horseradish peroxidase 16 to 120 days after transection, 74 percent of regenerating neurites grew in their normal projection pattern, rostal and contralateral to the cell body. One third of the neurites originated anomalously from posterior dendrites. Despite their initial abnormal orientation, 80 percent of these neurites looped contralaterally and rostrally to assume the normal projection path. The directional specificity persisted when giant interneurons were located in islands formed by double simultaneous cord transection. This limited regeneration seems to be characterized by directional selectivity that cannot be attributed to nonspecific influences, such as a tendency of neurites to grow in an already established direction or a trophic effect of the zone of injury.
Venous Pressure in Man During Weightlessness
Authors: Kirsch K. A. , Röcker L. , Gauer O. H. , Krause R. , Leach C. , Wicke H. J. , Landry R.
Published: October 2006

To determine whether the body fluid shift from the lower limbs toward the head that occurs during spaceflight leads to lasting increases of venous pressure in the upper body, venous pressure and hematocrit measurements were made on four astronauts before flight and 1 and 12 hours after recovery and compared with measurements in space. During the mission the hematocrit was elevated and the venous pressure lowered by 1 to 8 centimeters of water as compared with the preflight data. One hour after landing the hematocrit decreased, indicating a hemodilution, venous pressures were unexpectedly high, and a body weight loss of 4 to 5 percent was observed. Twelve hours later the venous pressures were the lowest recorded during the study. The fluid shift apparently takes place during the first several hours of spaceflight. Thereafter, the pressure in the peripheral veins and the central circulation is lower than that measured before flight.
Transforming Potential of Human c-
sis
Nucleotide Sequences Encoding Platelet-Derived Growth Factor
Authors: Josephs Steven F. , Ratner Lee , Clarke Michael F. , Westin Eric H. , Reitz Marvin S. , Wong-Staal Flossie
Published: October 2006

The nucleotide sequence of a transforming human c-
sis
complementary DNA shows an open reading frame 723 base pairs in length located downstream from an in-phase terminator thymine-guanine-adenine codon. Sequences within this region were identical to those previously determined for the exons of the normal human c-
sis
gene. Thus, the predicted transforming product, a protein of 27,281 daltons, may be the actual precursor for normal human platelet-derived growth factor chain A.
Skin Color and Nutrient Photolysis: An Evolutionary Hypothesis
Authors: Branda Richard F. , Eaton John W.
Published: October 2006

Human populations native to areas of intense sunlight tend to be heavily melanized. Previous explanations for this relationship have invoked only weak selective pressures. To test the hypothesis that dark pigmentation may protect against photolysis of crucial light-sensitive vitamins and metabolites by ultraviolet light, folate was used as a model. It was found that exposure of human plasma in vitro to simulated strong sunlight causes 30 to 50 percent loss of folate within 60 minutes. Furthermore, light-skinned patients exposed to ultraviolet light for dermatologic disorders have abnormally low serum folate concentrations, suggesting that photolysis may also occur in vivo. Deficiency of folate, which occurs in many marginally nourished populations, causes severe anemia, fetal wastage, frank infertility, and maternal mortality. Prevention of ultraviolet photolysis of folate and other light-sensitive nutrients by dark skin may be sufficient explanation for the maintenance of this characteristic in human groups indigenous to regions of intense solar radiation.
Translational Efficiency of Transfer RNA's: Uses of an Extended Anticodon
Authors: Yarus Michael
Published: October 2006

Transfer RNA's are probably very strongly selected for translational efficiency. In this article, the argument is presented that the coding performance of the triplet anticodon is enhanced by selection of a matching anticodon loop and stem sequence. The anticodon plus these nearby sequence features (the extended anticodon) therefore contains more coding information than the anticodon alone and can perform more efficiently and accurately at the ribosome. This idea successfully accounts for the relative efficiencies of many transfer RNA's.
Genetic Damage in
Escherichia coli
K12 AB2480 by Broad-spectrum Near-Ultraviolet Radiation
Authors: Webb Robert B. , Brown Mickey S.
Published: October 2006

Irradiation with either broad-spectrum near-ultraviolet [fluorescent BLB (black light blue)] or monochromatic wavelengths in the near-ultraviolet range (320 to 400 nanometers) can cause specific damage to DNA as shown in experiments with
Escherichia coli
K12 AB2480 at the stationary phase of growth.
Saccades Are Spatially, Not Retinocentrically, Coded
Authors: Mays Lawrence E. , Sparks David L.
Published: October 2006

Most models of the saccadic eye movement system imply that saccades are programmed for a certain distance and direction. Electrical stimulation of the brain was used to move the eyes of monkeys just before saccades to visual targets. Despite the stimulation-induced perturbation, saccades brought gaze to the target locations. This compensation indicates that saccades are coded to direct the eyes to a certain position in the orbit (or in space).
Effective Pulmonary Ventilation with Small-Volume Oscillations At High Frequency
Authors: Slutsky Arthur S. , Drazen Jeffrey M. , Ingram Roland H. , Kamm Roger D. , Shapiro Ascher H. , Fredberg Jeffrey J. , Loring Stephen H. , Lehr John
Published: October 2006

At high oscillation frequencies (4 to 30 hertz), effective alveolar ventilation can be achieved with tidal volumes much smaller than the anatomic dead space. An explanation of this phenomenon is given in terms of the combined effects of diffusion and convection and in terms of data consistent with the hypothesis. Theory and experimental results both show that the significant variable determining the effectiveness of gas exchange is the amplitude of the oscillatory flow rate independent of the individual values of frequency and stroke volume.
Molecular Basis of Bunyavirus Transmission by Mosquitoes: Role of the Middle-Sized RNA Segment
Authors: Beaty B. J. , Holterman M. , Tabachnick W. , Shope R. E. , Rozhon E. J. , Bishop D. H. L.
Published: October 2006

In an examination of the molecular basis of oral transmission of bunyaviruses by mosquitoes, La Crosse (LAC), snowshoe hare (SSH), and LAC-SSH reassortant viruses were compared in their ability to be transmitted to laboratory mice by the natural mosquito vector of LAC virus,
Aedes triseriatus
. Both LAC virus and the reassortment viruses containing the middle-sized (M) segment from the LAC parent were efficiently transmitted. In contrast, SSH virus and reassortment viruses containing the M RNA from the SSH parent were inefficiently transmitted. Thus, the M RNA segment, which codes for the virion glycoproteins, may be a major determinant of oral transmission of bunyaviruses by mosquitoes.
Mycoplasma pneumoniae
Infection: Role of a Surface Protein in the Attachment Organelle
Authors: Hu P. C. , Cole R. M. , Huang Y. S. , Graham J. A. , Gardner D. E. , Collier A. M. , Clyde W. A.
Published: October 2006

Attachment of
Mycoplasma pneumoniae
to host cells by means of a specialized terminus initiates infection. Monoclonal antibodies to a surface protein (P1) inhibit this process, and react with a region of the tip covered with peplomer-like particles. Since antibodies against the P1 protein are generated by natural and experimental infection and by immunization, the substance may be an important determinant of protective immunity.
Primitive Ducts of Renal Dysplasia Induced by Culturing Ureteral Buds Denuded of Condensed Renal Mesenchyme
Authors: Maizels Max , Simpson Sidney B.
Published: October 2006

Primitive ducts, the histological hallmark of human renal dysplasia, were induced in chick embryos by culturing ureteral buds denuded of condensed metanephrogenic mesenchyme.
Gene for Hereditary Retinoblastoma Assigned to Human Chromosome 13 by Linkage to Esterase D
Authors: Sparkes Robert S. , Murphree A. Linn , Lingua Robert W. , Sparkes Maryellen C. , Field L. Leigh , Funderburk Steve J. , Benedict William F.
Published: October 2006

Evaluation of three families with hereditary retinoblastoma demonstrates close linkage of the gene for this tumor with the genetic locus for esterase D. These results assign the gene for the hereditary form of retinoblastoma to band q14 on chromosome 13, the same region which is affected in the chromosome deletion form of this eye tumor, and therefore suggest a common underlying mechanism in the pathogenesis of these two forms of retinoblastoma.
Two-Component Hearing Sensations Produced by Two-Electrode Stimulation in the Cochlea of a Deaf Patient
Authors: Tong Y. C. , Dowell R. C. , Blamey P. J. , Clark G. M.
Published: October 2006

Dissimilarities in perception elicited by stimulation with two electrodes were estimated. A two-dimensional spatial configuration was found to be suitable to represent the dissimilarity data, and the two dimensions could be interpreted as corresponding to the position of the apical and basal electrode of the two-electrode combination. A speech-processing strategy that converts acoustic, first and second formants to two-electrode stimulation is proposed.
Extracts of Skeletal Muscle Increase Neurite Outgrowth and Cholinergic Activity of Fetal Rat Spinal Motor Neurons
Authors: Smith R. Glenn , Appel Stanley H.
Published: October 2006

A soluble extract of rat skeletal muscle increased neurite outgrowth and cholinergic activity of dissociated ventral spinal neurons in culture. The effects were concentration-dependent, saturable, and labile in the presence of heat or trypsin. The morphological enhancement was produced only by skeletal muscle extract and decreased with developmental age, whereas the cholinergic enhancement was produced by extracts of cerebral cortex and cardiac and skeletal muscle and did not change with age. These changes were specific for ventral cord neurons, but no species specificity was observed with respect to the muscle source or the neuronal target.
A Glycolipid Antigen Associated with Burkitt Lymphoma Defined by a Monoclonal Antibody
Authors: Nudelman E. , Kannagi R. , Hakomori S. , Parsons M. , Lipinski M. , Wiels J. , Fellous M. , Tursz T.
Published: October 2006

The antigen defined by a rat monoclonal antibody directed to a Burkitt lymphoma cell line was identified as globotriaosylceramide [Galα(1 → 4)-Galβ(1 → 4)-Glcβ(1 → 1)-ceramide]. The antibody demonstrated a strict steric specificity since it did not react with globoisotriaosylceramide [Galα(1 → 3)-Galβ(1 → 4)-Glcβ(1 → 1)-ceramide], the positional isomer of the antigen associated with the Burkitt lymphoma. Chemical analysis of various Burkitt lymphoma cell lines revealed that the Burkitt lymphoma cells contained more than 100 times as much of the glycolipid antigen as was found in other human lymphoma and leukemia cell lines.
Social Stress and Atherosclerosis in Normocholesterolemic Monkeys
Authors: Kaplan Jay R. , Manuck Stephen B. , Clarkson Thomas B. , Lusso Frances M. , Taub David M. , Miller Eric W.
Published: October 2006

Socially stressed adult male cynomolgus monkeys (
Macaca fascicularis
) fed a low fat, low cholesterol diet developed more extensive coronary artery atherosclerosis than unstressed controls. Groups did not differ in serum lipids, blood pressure, serum glucose, or ponderosity. These results suggest that psychosocial factors may influence atherogenesis in the absence of elevated serum lipids. Psychosocial factors thus may help explain the presence of coronary artery disease (occasionally severe) in people with low or normal serum lipids and normal values for the other "traditional" risk factors.
Visual System Anomalies in Human Ocular Albinos
Authors: Creel Donnell , O'Donnell Frank E. , Witkop Carl J.
Published: October 2006

Visually evoked potentials recorded from two types of human ocular albinos demonstrated significant hemispheric asymmetry following monocular stimulation. The asymmetry is indicative of disorganization of retinogeniculostriate projections similar to that reported for mammals with total albinism. Abnormal optic projections are associated with lack of ocular pigment and are not associated with any specific generalized pigment defect.
Molecular Conformation of a Halogen-Free Thyroxine Analog: 4′-Methoxy-3,5,3′-trimethyl-L-thyronine
N
-Acetyl Ethyl Ester
Authors: Cody Vivian
Published: October 2006

The molecular conformation of the halogen-free thyroxine analog 4′-methoxy-3,5,3′-trimethyl-L-thyronine
N
-acetyl ethyl ester has been determined by x-ray diffraction techniques. The unsubstituted parent compound, trimethylthyronine, has significant biological activity in rat thymocyte tests when compared with the thyroid hormone 3,5,3′-triiodo-L-thyronine (T
3
). Although no activity data are available for the analog studied, it is presumed to be inactive because of the 4′-methoxy blocking group. The observed conformation of this structure is similar to that found for the natural hormone T
3
. The 3′-methyl group is distal, the overall conformation is cisoid, and the diphenyl ether conformation is twist-skewed. The results of this diffraction study show that methyl substituents are capable of maintaining the thyronine conformation required for hormonal activity; they suggest that iodine enhances hormone-protein binding because of the electronic effects it produces either by alteration of molecular charge distributions or by direct charge-transfer interactions with the serum or nuclear binding proteins.
High-Resolution Scanning Transmission Electron Microscopy
Authors: Crewe A. V.
Published: October 2006

The high-resolution scanning transmission electron microscope is being used in a growing number of laboratories. This article provides a general overview of the instrument and its capabilities for readers who are unfamiliar with it.
Choline and Cholinergic Neurons
Authors: Blusztajn Jan K. , Wurtman Richard J.
Published: October 2006

Mammalian neurons can synthesize choline by methylating phosphatidylethanolamine and hydrolyzing the resulting phosphatidylcholine. This process is stimulated by catecholamines. The phosphatidylethanolamine is synthesized in part from phosphatidylserine; hence the amino acids methionine (acting after conversion to
S
-adenosylmethionine) and serine can be the ultimate precursors of choline. Brain choline concentrations are generally higher than plasma concentrations, but depend on plasma concentrations because of the kinetic characteristics of the blood-brain-barrier transport system. When cholinergic neurons are activated, acetylcholine release can be enhanced by treatments that increase plasma choline (for example, consumption of certain foods).
Recovery of Normal Topography in the Somatosensory Cortex of Monkeys After Nerve Crush and Regeneration
Authors: Wall John T. , Felleman Daniel J. , Kaas Jon H.
Published: October 2006

After median nerve fibers to glabrous skin on the hands of monkeys were crushed and allowed to regenerate, normal topographical organization was recovered in the representation of the hand in primary somatosensory cortex. Similar recovery of normal cortical organization may underlie the sensory restoration that usually follows nerve crush injury in humans.
An Accurate Drop Recorder
Authors: Gibbs O. S.
Published: October 2006

An improved form of drop recorder is described which has an accuracy of 600 drops per cc.
Nucleotide Sequence of Human Preproinsulin Complementary DNA
Authors: Sures Irmi , Goeddel David V. , Gray Alane , Ullrich Axel
Published: October 2006

Recombinant bacterial plasmids that contain DNA complementary to human preproinsulin messenger RNA have been constructed. One clone contains the entire preproinsulin coding region, as well as the 3′ untranslated region of the messenger RNA and eight nucleotides of the 5′ untranslated region. Additional sequence information for the 5′ untranslated region was obtained with the use of insulinoma messenger RNA in conjunction with specific primers from the cloned DNA for enzymatic chain termination sequence analysis. The results confirm the amino acid sequence of human proinsulin previously determined, and predict the amino acid sequence of the human preproinsulin signal peptide.
Picosecond Chemical and Biological Events
Authors: Rentzepis P. M.
Published: October 2006

Picosecond spectroscopy is a relatively new field of science that utilizes ultrashort laser pulses to monitor events taking place in the 10
-12
second regime. The continuing development of picosecond spectroscopy has made possible the detection and measurement of the primary events in many physical and biological processes. This article describes a currently used picosecond spectroscopy system that is capable of reliably recording picosecond events. Two areas of picosecond research are discussed; one concerns the interaction of electrons in fluids, and the second the primary events in vision.
Cocaine Plasma Concentration: Relation to Physiological and Subjective Effects in Humans
Authors: Javaid J. I. , Fischman M. W. , Schuster C. R. , Dekirmenjian H. , Davis J. M.
Published: October 2006

Volunteer subjects with previous histories of cocaine use were administered cocaine hydrochloride intravenously or intranasally. There was a positive relationship between peak plasma concentration, physiological and subjective responses, and dose administered. The rate of cocaine disappearance after intravenous administration paralleled the drop in physiological and subjective drug effects. After intranasal administration, blood levels remained elevated for a considerably longer period.
The Attention Operating Characteristic: Examples from Visual Search
Authors: Sperling George , Melchner Melvin J.
Published: October 2006

Even in the absence of eye movements, we show that subjects are able, upon instruction, to selectively attend to certain kinds of targets and parts of visual arrays. The major mechanism of altering attention is the switching of attention from trial to trial, although intermediate states of shared attention do occur. Attention operating characteristics are shown to be a useful way of describing such data and of assessing the compatibility of tasks to be performed simultaneously.
Intracranial Self-Stimulation in 3-Day-Old Rat Pups
Authors: Moran Timothy H. , Lew Mark F. , Blass Elliott M.
Published: October 2006

Three-day-old rat pups with electrodes directed at the medial forebrain bundle at the level of the lateral hypothalamic area were trained to push a paddle to receive electrical brain stimulation. Pups receiving stimulation that was contingent on lifting the paddle responded more frequently than did control pups and also learned a two-choice spatial discrimination task that was rewarded with brain stimulation. The experiments indicate that a neural substrate in the area of the medial forebrain bundle is involved in the central mediation of reinforcement in the rat pup.
Placental Mononuclear Phagocytes as a Source of Interleukin-1
Authors: Flynn Arthur , Finke James H. , Hilfiker Mary L.
Published: October 2006

Mouse and human placental tissue contains a large number of mononuclear phagocytes. These cells, isolated from placenta, were shown to produce the multifaceted immune factor interleukin-1. Activity in the supernatants of 48-hour mononuclear phagocyte cultures was associated with a 12,000- to 18,000-dalton protein, consistent with known interleukin-1 characteristics. Stimulation of phagocytosis with latex beads increased the production and release of interleukin-1 from these placental cells, which may be a useful source of this protein.
Estrogen and the Growth of Breast Cancer: New Evidence Suggests Indirect Action
Authors: Shafie Samir M.
Published: October 2006

The growth of the MCF-7 human breast cancer cell line is unresponsive to the presence of estrogen in culture media. Paradoxically, in nude mice, growth of these cells and formation of solid tumors are dependent on estrogen. Tumors fail to develop in ovariectomized mice, but do develop in intact mice and in ovariectomized mice given estrogen. Primary cultures derived from MCF-7 tumors revert to unresponsiveness to estrogen. However, when these cultures are again transplanted into nude mice, estrogen is required for tumor formation. The continuous culture, the solid tumor, and the primary cultures therefrom have similar estrogen-binding capacities and affinities. These results indicate that mammary carcinoma cell growth in vivo is subject to inhibition that can be overcome by estrogen.
Suckling
Authors: Blass Elliott M. , Teicher Martin H.
Published: October 2006

Suckling is the only behavior that is common among mammals. In newborn albino rats it is originally elicited by amniotic fluid deposited by the mother during parturition. Subsequent suckling is stimulated by saliva deposited on the nipples by the infant rats. Internal controls over the volume of milk suckled do not appear until infant rats are about 2 weeks of age at which time gastric distension, milk, systemic dehydration, and the intestinal hormone cholecystokinin suppress milk intake derived through suckling. The development of controls over suckling appetite appears to parallel that of consummatory control. Until about 2 weeks of age infant rats choose to suckle a nonlactating nipple with the same frequency as a lactating nipple. Thereafter, the lactating nipple is unanimously chosen. These studies suggest differences and commonalities in the suckling behavior of laboratory rats and other mammals.
Does Regeneration Follow Complete Ovariotomy in the Albino Rat?
Authors: Heys Florence M.
Published: October 2006

These two experiments seem to show that in the rat it is easily possible to be certain of getting out the entire ovary in young rats (under forty days old) and that upon complete removal no regeneration occurs.
Rapid Evolution of RNA Genomes
Authors: Holland John , Spindler Katherine , Horodyski Frank , Grabau Elizabeth , Nichol Stuart , VandePol Scott
Published: October 2006

RNA viruses show high mutation frequencies partly because of a lack of the proofreading enzymes that assure fidelity of DNA replication. This high mutation frequency is coupled with high rates of replication reflected in rates of RNA genome evolution which can be more than a millionfold greater than the rates of the DNA chromosome evolution of their hosts. There are some disease implications for the DNA-based biosphere of this rapidly evolving RNA biosphere.
Expression of
Treponema pallidum
Antigens in
Escherichia coli
Authors: Walfield Alan M. , Hanff Philip A. , Lovett Michael A.
Published: October 2006

Treponema pallidum
DNA was cloned in a bacteriophage. Clones were screened for expression of
Treponema pallidum
antigens by an in situ radioimmunoassay on nitrocellulose, with the use of subsequent reactions with syphilitic serum and radioiodinated
Staphylococcus aureus
protein A. One clone, which gave a strong signal, codes for at least seven antigens that react specifically with human antibodies to
Treponema pallidum
.
Ribosomal Crystalline Arrays of Large Subunits from
Escherichia coli
Authors: Clark Michael W. , Leonard Kevin , Lake James A.
Published: October 2006

Crystalline sheets of the 50
S
ribosomal subunits of
Escherichia coli
have been formed in vitro. Electron micrographs of these arrays diffract to 35-angstrom resolution. The lattice parameters of the crystals are
a
= 330 ± 20 angstroms,
b
= 330 ± 30 angstroms, and α = 123° ± 5°, and the space group is most likely p21. These arrays of ribosomal subunits are sufficiently ordered to resolve such known features of the large ribosomal subunit as the L7/L12 stalk and the central protuberance.
Lyme Disease—a Tick-Borne Spirochetosis?
Authors: Burgdorfer Willy , Barbour Alan G. , Hayes Stanley F. , Benach Jorge L. , Grunwaldt Edgar , Davis Jeffrey P.
Published: October 2006

A treponema-like spirochete was detected in and isolated from adult
Ixodes dammini
, the incriminated tick vector of Lyme disease. Causally related to the spirochetes may be long-lasting cutaneous lesions that appeared on New Zealand White rabbits 10 to 12 weeks after infected ticks fed on them. Samples of serum from patients with Lyme disease were shown by indirect immunofluorescence to contain antibodies to this agent. It is suggested that the newly discovered spirochete is involved in the etiology of Lyme disease.
Purinergic Regulation of Food Intake
Authors: Levine Allen S. , Morley John E.
Published: October 2006

Inosine peripherally administered to rats markedly suppressed spontaneous food intake and food intake induced by diazepam, muscimol, insulin, and food deprivation. The purines 2-deoxyguanosine and 2-deoxyinosine also suppressed food deprivation-induced feeding, whereas 7-methylinosine, which does not bind to the benzodiazepine binding site in vitro, had no effect on food intake when compared with controls. These results suggest that purines may represent endogenous substances that regulate food intake through interactions with the benzodiazepine receptor.
The National Cancer Chemotherapy Program
Authors: Frei Emil
Published: October 2006

The National Cancer Chemotherapy Program was initiated in 1955. It is administered and integrated by the Division of Cancer Treatment at the National Cancer Institute. The program involves the discovery and development of potential new antitumor agents; their screening in preclinical experimental systems for antitumor effect, and, if active, for toxicology; and, for selected agents, preliminary, and more definitive clinical trials. While serendipity and empiricism played a substantial role in the early years of the program, the program has increasingly emphasized and been influenced by advances in tumor biology, drug development, clinical pharmacology, and the science of clinical trials. There has been effective interaction between investigator-initiated research on the one hand and developmental research at preclinical and clinical levels on the other. Over 30 chemotherapeutic agents with substantial clinical antitumor activity have been discovered, and their proper use, often in combination and often integrated with surgery or radiotherapy, has resulted in significant progress in the effective treatment of many forms of cancer.
Emotions Are Expressed More Intensely on the Left Side of the Face
Authors: Sackeim Harold A. , Gur Ruben C. , Saucy Marcel C.
Published: October 2006

Pictures of human faces posing six distinct emotions (plus a neutral expression) and their mirror reversals were split down the midlines, and left-side and right-side composites were constructed. Subjects judged left-side composites as expressing emotions more intensely than right-side composites. The finding indicates hemispheric asymmetry in the control over emotional expression in the face.
Origin of the Retina from Both Sides of the Embryonic Brain: A Contribution to the Problem of Crossing at the Optic Chiasma
Authors: Jacobson Marcus , Hirose Giro
Published: October 2006

Cells originating from one of the first two blastomeres of the frog embryo were labeled either by injecting them with horseradish peroxidase or by changing the ploidy of one blastomere. Both methods show the labeled cells confined to the same side of the brain as the labeled blastomere except for cells that have moved from the opposite side into the ventral diencephalon and ventral part of the retina. Reciprocal movement of cells from each side of the prospective forebrain into the prospective retina on the opposite side starts before the neural tube closes and results in the formation of an incipient optic chiasma which may provide the pathway for optic axons to grow from the retina to the opposite side of the brain.