bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of Biological Materials by Use of Erbium (III)—Induced Magnetic Susceptibilities
Authors: Evans Christopher H. , Tew William P.
Published: October 2006

Positive magnetic susceptibilities can be introduced into biological materials by their sequestration of erbium (III) ions. Particles of such material may then be manipulated under the influence of an external magnetic field.
Circadian Rhythms of Blood Minerals in Humans
Authors: Markowitz Morri , Rotkin Laurence , Rosen John F.
Published: October 2006

Circadian rhythms of ionized calcium and phosphate concentrations have been demonstrated in human blood. A computer-derived model curve representing the 24-hour fluctuations in ionized calcium cannot be correlated consistently with curves for total calcium or phosphate. Knowledge of these circadian rhythms provides a physiological basis for further understanding the interactions between blood minerals and calcium-regulating hormones.
International Science—an Overview
Authors: Kerwin Larkin
Published: October 2006

Scientific projects that succeed as international cooperative efforts are those related to subjects that transcend national frontiers, are costly, have long-range objectives rather than short-term commercial aims, and correspond with the political objectives of the countries involved. Yet the best context for all of science is the global community, which is also the best hope for humanity. The global community is still generations away and scientists must continue to work for it, by seeking the international dimensions of science as individuals and participating in governmental as well as nongovernmental international scientific organizations.
Fertilizability of Ova Ovulated and Recovered from Rabbit Ovaries Perfused in Vitro
Authors: Kobayashi Yoshimune , Santulli Rosemary , Wright Karen H. , Wallach Edward E.
Published: October 2006

Ovaries removed from New Zealand White rabbits were perfused and exposed to gonadotropin in vitro. The ova ovulated in vitro (
N
= 56) were recovered and cultured and then transferred to the oviducts of six previously mated Dutch Belted hosts. Twelve of the resulting 36 offspring (33.3 percent) were white. In control matings between 12 Dutch Belted females (six randomly selected and the six hosts) and New Zealand White males, only one of 80 (1.2 percent) offspring was white. These data indicate that ova ovulated in vitro can be transferred to the oviduct of a host rabbit where they may be fertilized and after implantation may develop into viable embryos.
Autoantibodies from Vasectomized Guinea Pigs Inhibit Fertilization in Vitro
Authors: Huang Thomas T. F. , Tung Kenneth S. K. , Yanagimachi Ryuzo
Published: October 2006

Immunoglobulin G and Fab antibodies were isolated from the serum of vasectomized guinea pigs, and the effects of the antibodies on fertilization in vitro were investigated. These antibodies had profound inhibitory effects on (i) sperm-to-sperm adhesion, (ii) the acrosome reaction, (iii) sperm-zona binding, and (iv) sperm-ovum fusion. This finding may explain certain cases of infertility after vasovasostomy in men.
Optimization Theory Fails to Predict Performance of Pigeons in a Two-Response Situation
Authors: Mazur James E.
Published: October 2006

Optimization theory states that organisms behave in a way that maximizes reinforcement or "value." In a two-response situation, pigeons' response proportions approximately equaled reinforcement proportions, even when this behavior pattern substantially decreased the rate of reinforcement. Optimization or reinforcement maximization was not supported as the basic mechanism underlying choice behavior.
Retesting the Commitment Theory of Cellular Aging
Authors: Harley Calvin B. , Goldstein Samuel
Published: October 2006

The commitment theory of human fibroblast aging predicts that 55 percent of cells will be nondividing at the middle to late stages of the replicative lifespan; in the present study, however, fewer than 10 percent were nondividing. The fact that no immortal diploid cells have yet been reported is also at odds with the theory. Available data on the variable life-span of clones and mass cultures, the dependence of longevity on population size, and the predominance of certain cell types at termination of a culture are compatible with simpler theories, which support the idea that the limited replicative life-span of diploid fibroblasts is a valid model for organismic aging.
Origin of chi46,XX/46,XY Chimerism in a Human True Hermaphrodite
Authors: Dewald Gordon , Haymond Morey W. , Spurbeck Jack L. , Moore S. Breanndan
Published: October 2006

Using chromosome heteromorphisms and blood cell types as genetic markers, we demonstrated chimerism in a chi46,XX/46,XY true hermaphrodite. The pattern of inheritance of the chromosome heteromorphisms indicates that this individual was probably conceived by the fertilization, by two different spermatozoa, of an ovum and the second meiotic division polar body derived from the ovum and subsequent fusion of the two zygotes. This conclusion is based on the identification of the same maternal chromosomes 13, 16, and 21 in both the 46,XX and 46,XY cells of the patient. In the two cell lines of the chimera, chromosomal markers showed different paternal No. 9 chromosomes and sex chromosomes, as well as the same paternal chromosome 22.
X-ray and Neutron Scattering Density Profiles of the Intact Human Red Blood Cell Membrane
Authors: McCaughan Leon , Krimm S.
Published: October 2006

Hemoglobin-free human red blood cell membranes have been prepared with glutaraldehyde to maintain an intact structure on partial dehydration. Treatment of resealed ghosts with poly(L-lysine) produced an essentially constant structural unit and permitted correlation of electron microscopy results with x-ray and neutron diffraction profiles. These profiles provide detailed information, for the intact membrane, on the location and relative distribution of lipids and proteins.
Unequal Alternating Monocular Deprivation Causes Asymmetric Visual Fields in Cats
Authors: Tumosa Nina , Tieman Suzannah Bliss , Hirsch Helmut V. B.
Published: October 2006

Kittens were reared so that each eye received normal patterned vision on alternate days. If the eyes received equal periods of stimulation, the visual fields were normal. If one eye received much more experience than the other, the field of the less experienced eye was restricted to the temporal hemifield. This change, which differs from that observed when one or both eyes are deprived continuously of patterned input, suggests that an imbalance in the duration of stimulation can influence the outcome of the normal competitive interaction between pathways from the two eyes and can cause a selective suppression of a portion of the input from the less experienced eye. This suppression may involve the ipsilateral retino-geniculo-cortical pathways or it may involve the entire cortical pathway from the less experienced eye, leaving the colliculus to control responses to visual targets.
DNA Polymerases in Parasitic Protozoans Differ from Host Enzymes
Authors: Chang Lucy M. S. , Cheriathundam Elizabeth , Mahoney Eileen M , Cerami Anthony
Published: October 2006

Analysis of extracts of the bloodstream forms of
Trypanosoma brucei
showed that both DNA polymerase-α and DNA polymerase-β activities were present. The detection of DNA polymerase-β in
T. brucei
demonstrates the presence of this enzyme in unicellular organisms. DNA polymerase-β is present also in
Leishmania mexicana
. The DNA polymerases in
T. brucei
are immunologically distinct from the host enzymes. The structural differences between the parasite and the host enzymes could be exploited for the development of agents to combat parasitic diseases.
Aryl Hydrocarbon Hydroxylase from Humans Is Inhibited by Antibody to Rat Liver Cytochrome P-450
Authors: Robie-Suh K. , Robinson R. , Gelboin H. V. , Guengerich F. Peter
Published: October 2006

Antibody to the major purified cytochrome P-450 induced by 3-methylcholanthrene in rat liver strongly inhibits aryl hydrocarbon hydroxylase activity of uninduced and benz[
a
]anthracene-induced human monocytes and lymphocytes. Antibody to the cytochrome P-450 induced by phenobarbital has relatively little or no effect on the aryl hydrocarbon hydroxylase activity of the same human cells.
Intercellular Adhesion: Coconstruction of Contractile Heart Tissue by Cells of Different Species
Authors: Nag Asish C. , Cheng Mei
Published: October 2006

Dissociated embryonic rat myocardial cells and chick myocardial cells labeled with radioactive isotope coaggregate and establish intercellular junctions. These bispecific cells reconstruct synchronously beating myocardial tissue within 24 hours of culture.
Synthesis of the Contingent Negative Variation Brain Potential from Noncontingent Stimulus and Motor Elements
Authors: Rohrbaugh John W. , Syndulko Karl , Sanquist Thomas F. , Lindsley Donald B.
Published: October 2006

Slow shifts in brain potential (commonly called the contingent negative variation), obtained during a warned reaction-time task with a foreperiod of 1 second, were compared with waveforms synthesized by the addition of separately obtained potentials associated with individual (nonpaired) sensory stimuli and self-initiated motor movements. The synthesized waveforms match closely the actual contingent negative variation, suggesting that it is constituted largely of separate, noncontingent elements related to sensory and motor processes.
Genetic Mosaics of
Caenorhabditis elegans
: a Tissue-Specific Fluorescent Mutant
Authors: Siddiqui Shahid S. , Babu P.
Published: October 2006

Genetic mosaics can be generated by x-irradiation in the simple nematode
Caenorhabditis elegans
. A mutation in the gene
flu-3
alters the characteristic autofluorescence of intestinal cells under ultraviolet light and can be used as a cell- and tissue-specific marker. Embryos heterozygous for
flu-3
give rise to adults with patches of these altered intestinal cells. The previously established intestinal cell lineage in
Caenorhabditis elegans
and the distribution and sizes of the fluorescent patches are consistent with a somatic segregation of the
flu-3
allele.
Goal Orientation by Blindfolded Humans After Long-Distance Displacement: Possible Involvement of a Magnetic Sense
Authors: Baker R. Robin
Published: October 2006

A wide range of animals are able to orient toward home when subjected to displacement-release experiments. When comparable experiments are performed on blindfolded humans, a similar ability emerges. Such goal-orientation does not result from following the complete journey on a mental map, nor is it influenced by cloud cover. Bar magnets worn on the head do seem to exert an influence.
Isolation of O1 Serovars of
Vibrio cholerae
from Water by Serologically Specific Method
Authors: Hranitzky K. W. , Larson A. D. , Ragsdale D. W. , Siebeling R. J.
Published: October 2006

Vibrio cholerae
bacteria of the serological variety O1 were consistently isolated from water samples by passing the water with added Tween 20 through columns packed with polystyrene beads coated with antibodies against the O1 antigenic determinants. The beads from the columns were washed, transferred to alkaline peptone broth, and incubated. The O1 serovars were isolated and identified by established procedures.
Deoxyribonucleic Acid Structure: A New Model
Authors: Hopkins Robert C.
Published: October 2006

Models of deoxyribonucleic acid (DNA) having chain directions opposite to those of the Watson and Crick model offer strikingly different alternatives for DNA structures. Satisfactory models of the B and C forms of DNA have been built. Left-handed models readily form by twisting right-handed ones, and models can be bent into tight supercoils.
Hydra Mesoglea: a Model for Investigating Epithelial Cell—Basement Membrane Interactions
Authors: Day Robert M. , Lenhoff Howard M.
Published: October 2006

Isolated hydra mesoglea served as a suitable substrate for the attachment and spreading of hydra cells in vitro, irrespective of the species tested. Hydra cells did not attach and spread on substrates typically used for culturing mammalian cells. Mammalian and Drosophila cells attached and spread on plastic culture dishes but not on isolated mesoglea. Xenopus epithelial cells spread on both plastic and mesoglea. Because of the similarities of hydra mesoglea to vertebrate basement membranes, suggestions are offered for using mesoglea to study the interactions of epithelial cells with their basement membranes.
Instrumentation Needs of Research Universities
Authors: Berlowitz Laurence , Zdanis Richard A. , Crowley John C. , Vaughn John C.
Published: October 2006

This article assesses the status of scientific instruments in major research universities and identifies factors that facilitate or impede their development, acquisition, use, and maintenance. Sixteen universities, six national and government laboratories, and nine commercial laboratories were visited; over 700 individuals were interviewed. Data on instrument acquisition and age were collected. Instrumentation was examined in physics, chemistry, biological sciences, earth sciences, and electrical engineering. The study found that the quality of university instrumentation has seriously deteriorated, due principally to a relative decrease in instrumentation funding, inflexibility within the project grant system, and insufficient support for maintenance.
Ruminant Methane δ(
13
C/
12
C) Values: Relation to Atmospheric Methane
Authors: Rust Fleet
Published: October 2006

The δ(
13
C/
12
C) — values of methane produced by fistulated steers, dairy cattle, and wethers, and dairy and beef cattle herds show a bimodal distribution that appears to be correlated with the plant type (C
3
or C
4
, that is, producing either a three- or a four-carbon acid in the first step of photosynthesis) consumed by the animals. These results indicate that cattle and sheep, on a global basis, release methane with an average δ(
13
C/
12
C) value of -60 and -63 per mil, respectively. Together they are a source of atmospheric methane whose δ(
13
C/
12
C) is similar to published values for marsh gas and cannot explain the 20 per mil higher values for atmospheric methane.
T Cell Development in Mice that Lack the ζ Chain of the T Cell Antigen Receptor Complex
Authors: Love Paul E. , Shores Elizabeth W. , Johnson Mark D. , Tremblay Michel L. , Lee Eric J. , Grinberg Alexander , Huang Sing Ping , Singer Alfred , Westphal Heiner
Published: October 2006

The ζ subunit of the T cell antigen receptor complex is required for targeting nascent receptor complexes to the cell surface and for receptor-mediated signal transduction. To examine the significance of the ζ subunit in T cell development, mice deficient for ζ expression were generated by gene targeting. These ζ
-/-
mice had few CD4
+
CD8
+
thymocytes, and the generation of CD4
+
and CD8
+
single positive T cells was impaired but not completely abrogated. Peripheral T cells were present but were unusual in that they expressed small amounts of CD5 and few T cell receptors. Thus, ζ chain expression influences thymocyte differentiation but is not absolutely required for the generation of single positive T cells.
Leeuwenhoek's Observation of Bacteria
Authors: Casida L. E.
Published: October 2006

A form of dark-field illumination was produced that allows bacteria in aqueous suspension to be observed with both a Leeuwenhoek microscope and a compound microscope without a condenser. Possibly, this illumination was Leeuwenhoek's "particular method of observing" bacteria.
Spongy Bones in Prehistoric America
Authors: El-Najjar Mahmoud Y. , Robertson Abel L.
Published: October 2006

A well-preserved mummified child from about A.D. 1200 was recovered from Canyon de Chelly in northeastern Arizona in 1971. Striking skull changes were found and microscopic, ultrastructural, and cytochemical studies confirm the diagnosis of porotic hyperostosis that resulted in spongy bone appearance. We suggest that a possible cause for this condition could be iron deficiency of a severity seldom found in modern societies.
Intraclonal Histocompatibility in a Parthenogenetic Lizard: Evidence of Genetic Homogeneity
Authors: Cuellar Orlando
Published: October 2006

A total of 175 skin grafts were transplanted among 20 individuals belonging to two separate populations of the parthenogenetic lizard
Cnemidophorus uniparens
. Of these, 98.8 percent were permanently accepted, which indicates that all individuals of each population may be genetically identical. These results further suggest that large populations or the entire species may consist of one clone derived from a single individual.
Calcium-Independent Modulation of Cyclic GMP and Activation of Guanylate Cyclase by Nitrosamines
Authors: DeRubertis Frederick R. , Craven Patricia A.
Published: October 2006

Nitrosamines markedly increase concentrations of guanosine 3′,5′-monophosphate (cyclic GMP) in several tissues from the rat and in human colonic mucosa. These agents are effective in the absence of extracellular calcium and enhance guanylate cyclase activity in tissue homogenates. Stimulation of cyclic GMP was greatest in liver, where the carcinogenic activity of nitrosamines is also most pronounced.
Going for the Old: Ancient DNA Draws a Crowd
Authors: Fischman Joshua
Published: October 2006

Approximately 170 researchers interested in reconstructing the past convened for the 2nd International Conference on Ancient DNA, held in Washington, D.C., from 7 to 9 October. While rejuvenated celluloid dinosaurs have grabbed headlines this year, these scientists were more concerned with topics such as tracing ancient human populations and understanding how DNA can survive the millennia.
Synaptic Organization of the Amine-Containing Interplexiform Cells of the Goldfish and
Cebus
Monkey Retinas
Authors: Dowling John E. , Ehinger Berndt
Published: October 2006

Fluorescence microscopy has revealed a new type of amine-containing retinal neuron, the interplexiform cell, that extends processes in both plexiform layers. After intravitreal injection of 5,6-dihydroxytryptamine in goldfish and
Cebus
monkey, the processes of these cells can be identified by electron microscopy. In goldfish, the processes are pre- and postsynaptic to amacrine cells in the inner plexiform layer and presynaptic to bipolar and horizontal cells in the outer plexiform layer. Interplexiform cells thus provide an intraretinal centrifugal pathway from inner to outer plexiform layers.
Incisor Size and Diet in Anthropoids with Special Reference to Cercopithecidae
Authors: Hylander William L.
Published: October 2006

In 57 species of anthropoids relative size of incisors is highly correlated with diet. Anthropoids that feed primarily on large food objects (large fruits) have larger incisors than those that feed on smaller food objects (berries or leaves). This difference reflects a need for more extensive incisal preparation of larger food objects before mastication. Extensive incisal preparation causes increased tooth wear; therefore, enlarged incisors are probably an adaptive response to increase their wear potential.
Evidence for a Clonal Origin of Methicillin Resistance in
Staphylococcus aureus
Authors: Kreiswirth Barry , Kornblum John , Arbeit Robert D. , Eisner William , Maslow Joel N. , McGeer Allison , Low Donald E. , Novick Richard P.
Published: October 2006

Soon after methicillin was introduced into clinical practice in the early 1960s, resistant strains of
Staphylococcus aureus
(MRSA) appeared, bearing a newly acquired resistance gene,
mecA
, that encodes a penicillin binding protein, PBP2a. MRSA have spread throughout the world, and an investigation of the clonality of 472 isolates by DNA hybridization was performed. All 472 isolates could be divided into six temporally ordered
mecA
hybridization patterns, and three of these were subdivided by the chromomosomal transposon Tn
554
. Each Tn
554
pattern occurred in association with one and only one
mecA
pattern, suggesting that
mecA
divergence preceded the acquisition of Tn
554
in all cases and therefore that
mecA
may have been acquired just once by
S. aureus
.
Modulation of Cocaine Self-Administration in the Rat Through D-3 Dopamine Receptors
Authors: Caine S. Barak , Koob George F.
Published: October 2006

The reinforcing properties of cocaine are probably mediated by the mesocorticolimbic dopamine pathways in the central nervous system, but not all of the dopamine receptor subtypes involved in cocaine's reinforcing actions have been clearly identified. Recently, the D-3 receptor has been cloned, and its distribution in the brain has been found to be relatively restricted to limbic projections of the midbrain dopamine system. The D-3-selective compounds 7-hydroxy-
N
,
N
-di-n-propyl-2-aminotetralin (7-OHDPAT) and quinpirole potently decreased cocaine self-administration in the rat at doses that were not by themselves reinforcing. Moreover, three dopamine receptor agonists had affinities for binding to the D-3 receptor that correlated highly with their relative potencies in decreasing cocaine self-administration. The D-3 receptor may be involved in the reinforcing effects of cocaine and may be a useful target for the development of new pharmacotherapies for cocaine abuse.
Human CksHs2 Atomic Structure: a Role for Its Hexameric Assembly in Cell Cycle Control
Authors: Parge Hans E. , Arvai Andrew S. , Murtari Darren J. , Reed Steven I. , Tainer John A.
Published: October 2006

The cell cycle regulatory protein CksHs2 binds to the catalytic subunit of the cyclin-dependent kinases (Cdk's) and is essential for their biological function. The crystal structure of the protein was determined at 2.1 Å resolution. The CksHs2 structure is an unexpected hexamer formed by the symmetric assembly of three interlocked dimers into an unusual 12-stranded β barrel fold that may represent a prototype for this class of protein structures. Sequence-conserved regions form the unusual β strand exchange between the subunits of the dimer, and the metal and anion binding sites associated with the hexamer assembly. The two other sequence-conserved regions line a 12 Å diameter tunnel through the β barrel and form the six exposed, charged helix pairs. Six kinase subunits can be modeled to bind the assembled hexamer without collision, and therefore this CksHs2 hexamer may participate in cell cycle control by acting as the hub for Cdk multimerization in vivo.
The Stomach as a Site for Rapid Nutrient Reinforcement Sensors
Authors: Deutsch J. A. , Wang M.-L.
Published: October 2006

Rats with inflated cuffs placed around the pyloric sphincter were given a choice between two nonnutritive solutions. Ingestion of one solution was paired with nutritive intragastric injections, and ingestion of the other was paired with saline injections. The preference of rats for the nutrient-paired flavors indicates that the stomach alone can rapidly detect the arrival of nutritive substances.
Chloride Transport Across Isolated Opercular Epithelium of Killifish: A Membrane Rich in Chloride Cells
Authors: Karnaky Karl J. , Degnan Kevin J. , Zadunaisky Jose A.
Published: October 2006

The opercular epithelium of
Fundulus heteroclitus
contains typical gill chloride-secreting cells at the high density of 4 × 10
5
cells per square centimeter. When isolated, mounted as a membrane, and short-circuited, it actively transports chloride ions from the blood side to the seawater side of the preparation. This preparation offers a useful approach to the study of osmoregulation in bony fishes.
Intravenous Self-Feeding: Long-Term Regulation of Energy Balance In Rats
Authors: Nicolaïdis Stylianos , Rowland Neil
Published: October 2006

Rats learned to press a lever for intravenous self-injection of liquid diet during periods of several weeks when oral food was not available. The intakes were low but regulated, and were sufficient to balance energy expenditures at low body weight. Systemic receptors alone are thus adequate to motivate feeding behavior and meter the caloric yield of the intravenous injections.
Surface Molecules of Hematopoietic Stem Cells: Requirement for Sialic Acid in Spleen Colony Formation
Authors: Tonelli Quentin , Meintz Russel H.
Published: October 2006

Enzymatic treatment was used to test the function of some surface peptides and carbohydrates in hematopoietic spleen colony formation. Proteases and most glycosidases had no effect on spleen colony formation, whereas treatment with
Vibrio cholerae
neuraminidase reduced colonies by one-half. Intact sialic acid (residues) appear to play an important role in colony formation.
Deletion of
IRF-1
, Mapping to Chromosome 5q31.1, in Human Leukemia and Preleukemic Myelodysplasia
Authors: Willman Cheryl L. , Sever Cordelia E. , Pallavicini Maria G. , Harada Hisashi , Tanaka Nobuyuki , Slovak Marilyn L. , Yamamoto Hitomi , Harada Kenji , Meeker Timothy C. , List Alan F. , Taniguchi Tadatsugu
Published: October 2006

One of the most frequent cytogenetic abnormalities in human leukemia and myelodysplasia is an interstitial deletion within chromosome 5q. A tumor suppressor gene has been hypothesized to lie in 5q31, the smallest commonly deleted region.
IRF-1
, a gene whose product manifests anti-oncogenic activity, was mapped to 5q31.1.
IRF-1
lies between
IL-5
and
CDC25C
and is centromeric to
IL-3
and
GM-CSF
. Among these genes, only
IRF-1
was consistently deleted at one or both alleles in 13 cases of leukemia or myelodysplasia with aberrations of 5q31. Inactivating rearrangements of one
IRF-1
allele, accompanied by deletion of the second allele, were also identified in one case of acute leukemia. Thus,
IRF-1
may be a critically deleted gene in human leukemia and myelodysplasia.
On the Application of the Minimal Principle to Solve Unknown Structures
Authors: Miller Russ , DeTitta George T. , Jones Rob , Langs David A. , Weeks Charles M. , Hauptman Herbert A.
Published: October 2006

The Shake-and-Bake method of structure determination is a new direct methods phasing algorithm based on a minimum-variance, phase invariant residual, which is referred to as the minimal principle. Previously, the algorithm had been applied only to known structures. This algorithm has now been applied to two previously unknown structures that contain 105 and 110 non-hydrogen atoms, respectively. This report focuses on (i) algorithmic and parametric optimizations of Shake-and-Bake and (ii) the determination of two previously unknown structures. Traditional tangent formula phasing techniques were unable to unravel these two new structures.
Requirement for Tyrosine Kinase p56

lck

for Thymic Development of Transgenic γδ T Cells
Authors: Penninger Josef , Kishihara Kenji , Molina Thierry , Wallace Valerie A. , Timms Emma , Hedrick Stephen M. , Mak Tak W.
Published: October 2006

The Src-related protein tyrosine kinase p56

lck

is essential for antigen-specific signal transduction and thymic maturation of T cells that have an αβ T cell receptor (TCR), presumably by physical association with CD4 or CD8 molecules. To evaluate the requirement for p56

lck

in the development of T cells that have γδ TCRs, which generally do not express CD4 or CD8, p56

lck

mutant mice were bred with TCRγδ transgenic mice. Few peripheral cells that carried the transgenes could be detected in p56

lck
-/-

mice, although 70 percent of thymocytes were transgenic. Development of transgenic γδ
+
thymocytes was blocked at an early stage, defined by interleukin-2 receptor α expression. However, extrathymic development of CD8 αα
+
TCRγδ
+
intestinal intraepithelial lymphocytes appeared to be normal. Thus, p56

lck

is crucial for the thymic, but not intestinal, maturation of γδ T cells and may function in thymic development independently of CD4 or CD8.
Hypothalamic Stimulation Facilitates Contralateral Visual Control of a Learned Response
Authors: Beagley Walter K. , Holley Terry L.
Published: October 2006

Rats that ate during hypothalamic stimulation were trained to press a lever for food only while receiving light signals from head-mounted lights. During stimulation, they pressed if the signal was visible to the eye contralateral to the electrode, but ignored the signal if it was visible only to the ipsilateral eye.
Sea Urchin Recruitment Patterns and Implications of Commercial Fishing
Authors: Tegner Mia J. , Dayton Paul K.
Published: October 2006

Coexisting sea urchins
Strongylocentrotus purpuratus
and
S. franciscanus
exhibit different recruitment patterns. Juveniles of the former species are found in a variety of habitats, whereas juveniles of the latter occur almost exclusively under the spine canopy of conspecific adults. The commercial harvest of
S. franciscanus
thus seems to affect nursery grounds as well as the reproductive potential of exploited populations.
Repression of MHC Class I Gene Promoter Activity by Two-Exon Tat of HIV
Authors: Howcroft T. Kevin , Strebel Klaus , Martin Malcolm A. , Singer Dinah S.
Published: October 2006

Major histocompatibility complex (MHC) class I molecules are the major receptors for viral peptides and serve as targets for specific cytotoxic T lymphocytes. Human immunodeficiency virus-type 1 (HIV-1) specifically decreased activity of an MHC class I gene promoter up to 12-fold. Repression was effected by the HIV-1 Tat protein derived from a spliced viral transcript (two-exon Tat). These studies define an activity for two-exon Tat distinct from that of one-exon Tat and suggest a mechanism whereby HIV-1-infected cells might be able to avoid immune surveillance, allowing the virus to persist in the infected host.
Lesch-Nyhan Syndrome: Low Dopamine-β-Hydroxylase Activity and Diminished Sympathetic Response to Stress and Posture
Authors: Lake C. Raymond , Ziegler Michael G.
Published: October 2006

Patients with Lesch-Nyhan syndrome with virtually no hypoxanthine phosphoribosyltransferase activity demonstrate significantly low plasma activity of dopamine-β-hydroxylase but normal basal levels of norepinephrine. Under conditions of emotional or postural stress the plasma concentrations of norepinephrine in Lesch-Nyhan patients increased less than in a normal population.
DNA Polymerase with Characteristics of Reverse Transcriptase Purified from Human Milk
Authors: Kantor Judith A. , Lee Yan-Hwa , Chirikjian Jack G. , Feller William F.
Published: October 2006

A DNA polymerase purified from a particulate fraction of human milk has biochemical and biophysical properties similar to those of viral reverse transcriptases. This enzyme is immunologically distinct from cellular DNA polymerases obtained from a variety of human sources.
Controlling the Pink Bollworm by Disrupting Sex Pheromone Communication Between Adult Moths
Authors: Gaston Lyle K. , Kaae R. S. , Shorey H. H. , Sellers D.
Published: October 2006

The synthetic sex pheromone (gossyplure) of the pink bollworm was evaporated into the atmosphere of three cotton fields during an entire growing season. The resulting disruption of premating pheromone communication between male and female moths led to a reduction in the population of larvae infesting cotton bolls. This larval control was comparable, in terms of both effectiveness and expense of materials used, to the control achieved in ten comparison fields by growers using conventional insecticide applications.
Siamese Cats: Abnormal Responses of Retinal Ganglion Cells
Authors: Chino Yuzo M. , Shansky Michael S. , Hamasaki D. I.
Published: October 2006

Comparison of optic tract recordings in Siamese and ordinary cats reveals that Siamese cats have a significantly lower percentage of Y-cells than of X-cells. In addition, Siamese cats show depressed responses to a contrast-reversal stimulus, a result that supports the lower spatial contrast sensitivity demonstrated behaviorally by these animals. Both physiological findings suggest neurophysiological anomalies in the Siamese retina.
Induction of Acetylcholinesterase Activity by β-Ecdysone in a
Drosophila
Cell Line
Authors: Cherbas Peter , Cherbas Lucy , Williams Carroll M.
Published: October 2006

When cells of the
Drosophila
Kc-H line are treated with ≥ 10
-8
molar β-ecdysone, they extend long processes and acquire acetylcholinesterase activity. Thus, this permanent line, derived originally from embryo cultures, may be composed of cells having some neural or glial characteristics.
Inhibition of a Lymphocyte Membrane Enzyme by Δ
9
-Tetrahydrocannabinol in Vitro
Authors: Greenberg J. H. , Saunders M. E. , Mellors A.
Published: October 2006

Delta-9-tetrahydrocannabinol (Δ
9
-THC) inhibited the activity of lysolecithin acyl transferase, a membrane-bound lymphocyte enzyme, at concentrations above 1.3 μ
M
. Stimulation of acyl transferase activity by concanavalin A, an early response in lymphocyte activation, was entirely abolished in the presence of Δ
9
-THC.
Liquid Chromatographic Analysis of Endogenous Catecholamine Release from Brain Slices
Authors: Plotsky Paul M. , Wightman R. Mark , Chey Willie , Adams Ralph N.
Published: October 2006

A simple new liquid chromatographic technique has been applied to transmitter release studies in brain slice preparations. This method, which gives direct readings of picomoles of endogenous transmitter released, has been shown to yield reliable results with a variety of brain slice manipulations.
Psoralen-DNA Photoreaction: Controlled Production of Mono- and Diadducts with Nanosecond Ultraviolet Laser Pulses
Authors: Johnston Brian H. , Johnson Mark A. , Moore C. Bradley , Hearst John E.
Published: October 2006

Samples of DNA which contain adducts of a new psoralen derivative, but no cross-links, have been prepared by irradiating mixtures of DNA and the derivative with single, 15-nanosecond pulses of laser light. Succeeding pulses introduce cross-links. The ability to rapidly and selectively create monoadducts and cross-links may allow the use of psoralens as probes of dynamic processes in living cells.
Communication Deviance in the Families of Schizophrenics: A Comment on the Misuse of Analysis of Covariance
Authors: Woodward J. Arthur , Goldstein Michael J.
Published: October 2006

Serious contradictions in recent research programs concerning communication anomalies in parents of schizophrenics have been generated by invalid statistical analyses. The method of analysis used, the analysis of covariance, can lead to erroneous conclusions in the context of these studies, and thus, other means must be sought for bringing these important research programs into common focus.
Infectivity Reacquisition by
Trypanosoma brucei brucei
Cultivated with Tsetse Salivary Glands
Authors: Cunningham Isabel , Honigberg B. M.
Published: October 2006

Reacquisition of infectivity for mice was observed in cultures of
Trypanosoma brucei brucei
grown in the presence of tsetse fly salivary gland explants in a medium based on the amino acid composition of
Glossina
hemolymph and containing fetal bovine serum. High infection rates were obtained in mice inoculated with about 1.5 × 10
8
organisms. Infectivity reacquisition was correlated with invasion of the salivary glands by the parasites. Few small trypanosomes with subterminal kinetoplasts (metacyclic-like forms) were found in the infective inoculums. The parasitemias in mice consisted of pleomorphic cultivable trypanosomes. Cultures initiated by these organisms and then placed with the head-salivary gland preparations became infective for mice.
A Method for Detecting 8-Methoxypsoralen in the Ocular Lens
Authors: Lerman Sidney , Borkman Raymond F.
Published: October 2006

The use of 8-methoxypsoralen for treating psoriasis could prove hazardous if this photosensitizing agent enters the ocular lens. Phosphorescence spectra of intact rat lenses reveal concentrations of 8-methoxypsoralen on the order of 10
-5
M
after intraperitoneal injection of 8-methoxypsoralen. There is evidence that this drug can function as a photosensitizing agent, enhancing ultraviolet-induced changes within the lens.
Bifunctional Intercalators: Relationship of Antitumor Activity of Diacridines to the Cell Membrane
Authors: Fico Rosario M. , Chen Teh Kuei , Canellakis E. S.
Published: October 2006

The in vivo antitumor effectiveness [as measured by the percentage increase in life-span (ILS%)] of 28 diacridine bis-intercalators of nucleic acids shows a highly significant correlation with their effect on phenomena associated with plasma membrane as well as a high degree of structural specificity. In contrast, the ILS% does not correlate with the uptake of these diacridines by cells, nor with the inhibition of RNA synthesis or of DNA synthesis or with the inhibition of growth of cells in culture. The possibility that the antitumor effectiveness of actinomycin D, another DNA intercalator, is associated with sites of action other than the hibition of RNA synthesis is discussed.
β-Endorphin: Endogenous Opiate or Neuroleptic?
Authors: Segal David S. , Browne Ronald G, , Bloom Floyd , Ling Nicholas , Guillemin Roger
Published: October 2006

The opiatelike neuropeptide β-endorphin produces a spectrum of effects that contrasts with that induced by the neuroleptic haloperidol. Rats injected intraventricularly or directly into the periaqueductal gray with β-endorphin (0.5 to 50 micrograms) exhibited rigid immobility accompanied by the loss of righting reflex; the period of rigidity was preceded or followed (depending upon dose) by a state of hyperactivity. In contrast, no dose of haloperidol tested (0.5 to 12 milligrams per kilogram) produced rigidity, loss of righting reflex, or behavioral excitation. Furthermore, whereas animals injected with haloperidol remained stationary on a vertical grid, rats injected with β-endorphin typically slid off the grid. Moreover, combined β-endorphin and haloperidol treatment produced flaccidity in most animals. These results do not support the contention that this opiatelike peptide may be a naturally occurring neuroleptic.
Reversal of Cardiopulmonary Failure During Active Sleep in Hypoxic Kittens: Implications for Sudden Infant Death
Authors: Baker Theodore L.. , McGinty Dennis J.
Published: October 2006

Experimentally induced hypoxia in kittens precipitated episodes of depressed respiration and irregular cardiac function during quiet sleep, waking, and transitional states. The onset of active sleep stimulated both breathing and heart rate and decreased abnormal variability in these functions. However, hypoxia markedly reduced the proportion of active sleep. These data suggest that active sleep protects against respiratory and cardiac abnormalities in infants. Chronic hypoxemia or other factors that reduce active sleep in infants, including the normal developmental decrement in this state, may increase the risk of cardiopulmonary failure and death.
Circular Forms of DNA Synthesized by Rous Sarcoma Virus in Vitro
Authors: Clayman Carol H. , Mosharrafa Enayat T. , Anderson Dwight L. , Feras Anthony J.
Published: October 2006

Electron microscopic analysis of the DNA product synthesized by detergent-disrupted preparations of Rous sarcoma virus in vitro revealed the presence of several interesting molecular forms including covalently closed circular DNA. The identification of such circular DNA indicates that virions of retroviruses contain all the components necessary to facilitate the complete synthesis of mature forms of viral DNA and therefore provide a useful system to delineate the molecular mechanisms involved in their synthesis.
Degenerating Nerve Fiber Products Do Not Alter Physiological Properties of Adjacent Innervated Skeletal Muscle Fibers
Authors: Tiedt Thomas N. , Albuquerque Edson X. , Guth Lloyd
Published: October 2006

Partial denervation of rat extensor digitorum longus and soleus muscles resulted in the appearance of denervated and innervated surface muscle fibers lying adjacent to one another. The denervated muscle fibers showed the typical signs of denervation while the innervated muscle fibers were similar to those of control muscles. We conclude that denervated fibers do not induce substantial physiological changes in adjacent innervated muscle fibers.
The Isolation in Pure Form of the Interstitial Cell-stimulating (Luteinizing) Hormone of the Anterior Lobe of the Pituitary Gland
Authors: Shedlovsky Theodore , Rothen A. , Greep R. O. , van Dyke H. B. , Chow Bacon F.
Published: October 2006

Interstitial cell-stimulating (luteinizing) hormone was isolated from swine pituitary glands. This protein hormone, having a molecular weight of about 90,000 and an isoelectric point of pH 7.45, was shown to be pure by tests in the electrophoresis apparatus of Tiselius and in the ultracentrifuge as well as by its constant solubility. The hormone stimulated the interstitial tissue of the testis or ovary and caused the formation of corpora lutea provided that maturing follicles were present. Under the conditions described, its minimal effective total dose in hypophysectomized immature male rats was about 1 microgram of nitrogen or 6.7 micrograms of hormone. Extracts of swine pituitary with purely follicle-stimulating effects did not cause oestrus in immature hypophysectomized female rats unless luteinizing hormone was also administered.
Minimum Size of Mammalian Homeotherms: Role of the Thermal Environment
Authors: Tracy C. Richard
Published: October 2006

The minimum size of a mammalian homeotherm appears to be related to the animal's maximum rate of endogenous heat production, the ambient thermal environment, and the animal's ability to be a facultative homeotherm.
Masking of Electrical by Acoustic Stimuli: Behavioral Evidence for Tonotopic Organization
Authors: Frederickson Christopher J. , Gerken George M.
Published: October 2006

When pure-tone acoustic masking stimuli of various frequencies were presented simultaneously with electrical stimuli applied to cochlear nucleus, only those maskers within a limited frequency range interfered with the detection of the electrical stimuli. The form of the masking functions obtained suggests that the electrical stimulus directly activated only a small population of neurons which were functioning in a tonotopic fashion.
(+)-α-(
N
-1-Phenethyl)Urea Stereospecifically Inhibits Ca
2+
- But Not ADP-Stimulated Mitochondrial Respiration
Authors: Davidoff F. , Haas D. , Bertolini D.
Published: October 2006

The (+) isomer of α-(
N
-1-phenethyl)urea is a moderately potent inhibitor of Ca
2+
-stimulated mitochondrial respiration of
45
Ca
2+
uptake (50 percent inhibition at ∼0.18 m
M
) while having no effect on adenosine diphosphate-stimulated respiration; the (-) isomer is without effect up to 4 m
M
. β-Phenethylurea does not inhibit with either stimulus. The data support the involvement of a Ca
2+
-specific protein in energized mitochondrial Ca
2+
uptake.
Clonal Origin of Inherited Medullary Thyroid Carcinoma and Pheochromocytoma
Authors: Baylin Stephen B. , Gann Donald S. , Hsu Susan H.
Published: October 2006

A black female with inherited medullary thyroid carcinoma and pheochromocytoma was a mosaic for glucose-6-phosphate dehydrogenase types A and B in normal tissues (blood, thyroid, and adrenal gland); both the medullary carcinoma and pheochromocytoma tissue showed a B pattern only. This finding suggests a single clone origin for each of the tumors. Other inherited tumors similarly studied in man have appeared to be multiclonal in origin.
Intracellular 5-Phosphoribosyl-1-Pyrophosphate: Decreased Availability During Glutamine Limitation
Authors: Skaper Stephen D. , Willis Randall C. , Seegmiller J. Edwin
Published: October 2006

Culture of human lymphoblasts in medium containing limited glutamine (less than 0.2 millimolar) effects an inhibition of purine base reutilization and synthesis de novo. Both processes appear to be inhibited by a decreased availability of the common substrate 5-phosphoribosyl-1-pyrophosphate. Under conditions of glutamine limitation, the maintenance of capacity for purine base utilization and synthesis de novo and consequently growth was dependent on supplementation of cultures with inosine. The purine nucleoside provides a source of ribose phosphate for synthesis of 5-phosphoribosyl-1-pyrophosphate. Glutamine limitation may result in a decreased availability of ribose-5-phosphate.
Cholera Toxin-Peroxidase: Changes in Surface Labeling of Glioblastoma Cells with Increased Time in Tissue Culture
Authors: Manuelidis Laura , Manuelidis Elias E.
Published: October 2006

Cholera toxin coupled to peroxidase yielded a highly specific ultrastructural marker of plasma membrane monosialogangliosides. Studies with cultures of brain and brain tumors suggested that long-term culture of tissue in monolayers results in eventual loss of surface monosialogangliosides.
Histones and G Banding of Chromosomes
Authors: Holmquist Gerald P. , Comings David E.
Published: October 2006

Polylysine, polyarginine, and histones H1, H2A, H2B, and H3 inhibit Giemsa staining and chromosome banding by binding to DNA and preventing side stacking of the positively charged thiazine dyes to the negatively charged phosphate groups on DNA. This is a nonspecific effect and does not of itself provide evidence for a role of histones in G banding. The question of whether histones are involved in chromosome banding is reviewed.
Calcium Release from Skeletal Muscle Sarcoplasmic Reticulum: Site of Action of Dantrolene Sodium?
Authors: Van Winkle W. B.
Published: October 2006

The muscle relaxant dantrolene sodium acts directly and specifically on skeletal muscle, unlike other pharmacological agents which affect the central nervous system or act at the nueromuscular junction. Dantrolene sodium markedly suppresses the release of calcium previously sequestered by skeletal, but not cardiac, muscle sarcoplasmic reticulum. No effect in the total amount of calcium accumulated was found. In situ, the drug may reduce the amount of calcium necessary for muscle contraction.
Man-Made Radionuclides and Sedimentation in the Hudson River Estuary
Authors: Simpson H. J. , Olsen C. R. , Trier R. M. , Williams S. C.
Published: October 2006

Recently deposited fine-grained sediments in the Hudson River estuary contain radionuclides from global fallout produced by atmospheric bomb tests as well as from low-level releases of a local nuclear reactor. Accumulation rates of these nuclides are dependent on rates of sediment deposition and vary with location in the estuary by more than two orders of magnitude. Within the Hudson estuary, New York harbor is currently the zone of most rapid deposition of sediments containing radionuclides, some of which were released from a nuclear reactor about 60 kilometers upstream of the harbor.
Thermorestoration of Mutagenic Radiation Damage in Bacterial Spores
Authors: Tanooka Hiroshi
Published: October 2006

The frequency of mutations in
Bacillus subtilis
spores irradiated anoxically with ionizing radiation decreased as a result of subsequent anoxic heating to the same extent as the increase in spore survival. This result indicates that DNA damage is the origin of the "thermorestoration" phenomenon.
Some Chemical and Pharmacological Observations on "Low Nicotine" Tobacco
Authors: Haag H. B. , Larson P. S.
Published: October 2006

Chemical and pharmacological tests have been carried out on a sample of "low nicotine" tobacco. Laboratory tests involving toxicological studies on mice and blood pressure determinations in the dog showed that the toxic and vasopressor effects of the smoke from this tobacco was proportional to the amount of nicotine present and relatively independent of the nornicotine content of the tobacco. On man the smoke from these low nicotine cigarettes produced very much less pronounced effects on blood pressure and pulse rate than that produced by ordinary cigarettes. These results indicate that this type of tobacco is sufficiently low in nicotine to make it practically deserving of much further study.
A Sensitive Color Reaction for the Detection of Uracil and Cytosine
Authors: Johnson Treat B.
Published: October 2006

(1) Uracil and cytosine are both transformed quantitatively into 5,5-dichloroxyhydrouracil by interaction with superoxol and concentrated hydrochloric acid.

(2) This 5,5-dichloroxyhydrouracil reacts with barium hydroxide immediately at ordinary temperature giving the purple colored barium salt of dialuric acid.

(3) Both uracil and cytosine can be detected successfully in minute quantities by application of the technique discussed in this paper.