bluuebunny/crossref_metadata_2025 huggingface dataset:
Implication of Nonlinear Kinetics on Risk Estimation in Carcinogenesis
Authors: Hoel David G. , Kaplan Norman L. , Anderson Marshall W.
Published: October 2006

Efforts in estimating carcinogenic risk in humans from long-term exposure to chemical carcinogens have centered on the problem of low-dose extrapolation. For chemicals with metabolites that interact with DNA, it may be more meaningful to relate tumor response to the concentration of the DNA adducts in the target organ rather than to the applied dose. Many data suggest that the relation between tumor response and concentration of DNA adducts in the target organ may be linear. This implies that the nonlinearities of the dose-response curve for tumor induction may be due to the kinetic processes involved in the formation of carcinogen metabolite—DNA adducts. Of particular importance is the possibility that the kinetic processes may show a nonlinear "hockey-stick" like behavior which results from saturation of detoxification or DNA repair processes. The mathematical models typically used for low-dose extrapolation are shown potentially to overestimate risk by several orders of magnitude when nonlinear kinetics are present.
In Vivo Phosphorus-31 Nuclear Magnetic Resonance Reveals Lowered ATP During Heat Shock of
Tetrahymena
Authors: Findly R. C. , Gillies R. J. , Shulman R. G.
Published: October 2006

Cells synthesize a characteristic set of proteins—heat shock proteins—in response to a rapid temperature jump or certain other stress treatments. The technique of phosphorus-31 nuclear magnetic resonance spectroscopy was used to examine in vivo the effects of temperature jump on two species of Tetrahymena that initiate the heat shock response at different temperatures. An immediate 50 percent decrease in cellular adenosine triphosphate was observed when either species was jumped to a temperature that strongly induces synthesis of heat shock proteins. This new adenosine triphosphate concentration was maintained at the heat shock temperature.
Overproduction and Elimination of Retinal Axons in the Fetal Rhesus Monkey
Authors: Rakic Pasko , Riley Katharine P.
Published: October 2006

Quantitative electron microscopic analysis reveals 2.85 million retinal axons in fetal rhesus monkeys—a number that is more than twice the 1.2 million present in the adult. More than 1 million supernumerary optic axons are eliminated before birth, simultaneously with the segregation of inputs from the two eyes into separate layers of the lateral geniculate nucleus. Selective elimination of optic axons may not only play a role in the segregation of binocular visual connections but, secondarily, may establish the ratio of crossed and uncrossed retinogeniculate projections.
Mechanical Measurement of Red Cell Membrane Thickness
Authors: Hochmuth R. M. , Evans C. A. , Wiles H. C. , McCown J. T.
Published: October 2006

The thickness of intact human red cell membrane is measured by a light-microscope technique in which membrane material with a known surface area is extracted into a long, thin cylindrical strand. The radius of the strand is calculated from its known length and surface area. The minimum radius, obtained at high extraction velocities or large membrane tensions, is 55 angstroms. A collapsed membrane cylinder with a mean-mass radius of 55 angstroms would have a membrane thickness of 78 angstroms.
Mechanical Action of the Intercostal Muscles on the Ribs
Authors: De Troyer André , Kelly Suzanne , Zin Walter A.
Published: October 2006

The external and internal interosseous intercostal muscles were separately stimulated at end-expiratory lung volume in anesthetized dogs. These muscles were all found to elevate the ribs into which they insert. By attaching weights to the ribs, it was determined that the nonlinear compliance of the ribs was responsible for this phenomenon.
Dopamine Modulation of the Effects of γ-Aminobutyric Acid on Substantia Nigra Pars Reticulata Neurons
Authors: Waszcak Barbara L. , Walters Judith R.
Published: October 2006

Studies were conducted to assess whether basal ganglia output neurons originating in the substantia nigra pars reticulata might be affected by dopamine released from dendrites of neighboring substantia nigra pars compacta neurons. Dopamine applied by iontophoresis increased the baseline firing rates of approximately half of the substantia nigra pars reticulata cells tested. The more significant finding, unrelated to the increase in firing, was the ability of dopamine to attenuate the inhibitory responses of these cells to iontophoretically applied γ-aminobutyric acid. These findings suggest a role for dopamine as a neuromodulator and further suggest that it can act at sites beyond the striatum to modify transmission from the basal ganglia to motor nuclei.
Altered Activity in the Hippocampus Is More Detrimental to Classical Conditioning Than Removing the Structure
Authors: Solomon Paul R. , Solomon Scott D. , Vander Schaaf Ellen , Perry Holly E.
Published: October 2006

Hippocampal ablation has no effect on the acquisition of the rabbit's classically conditioned nictitating membrane response. Systemic administration of scopolamine, which alters hippocampal neuronal activity, severely retards acquisition of the conditioned response in normal animals and those with cortical ablations. In animals with hippocampal ablations, however, scopolamine has no effect on conditioning. These findings suggest that altered neuronal activity in the hippocampus is more detrimental to conditioning than removing the structure.
Metastable Species of Hemoglobin: Room Temperature Transients and Cryogenically Trapped Intermediates
Authors: Ondrias M. R. , Friedman J. M. , Rousseau D. L.
Published: October 2006

Resonance Raman spectra of photolyzed carbonmonoxyhemoglobin obtained with 10-nanosecond pulses are compared with the spectra of photolyzed carbonmonoxyhemoglobin stabilized at 80 K. In comparing the deoxy with the photodissociated species, the changes in the Raman spectra are the same for these two experimental regimes. These results show that at ambient and cryogenic temperatures the heme pocket in liganded hemoglobin is significantly different from that of deoxyhemoglobin. It is concluded that measurements of the properties of intermediate species from photodissociated hemoglobin stabilized at low temperatures can be used to probe the short-lived metastable forms of hemoglobin present after photodissociation under biologically relevant solution conditions.
Estrogen-Binding Sites in Endothelial Cell Cultures
Authors: Colburn P. , Buonassisi V.
Published: October 2006

The cytosol extracted from a vascular endothelial cell line binds [
3
H]estradiol with high affinity and a high degree of specificity. In contrast, in experiments performed with cytosol labeled in the intact cell, progesterone and, to a smaller extent, testosterone gave an apparent inhibition of estradiol binding. These data support the concept that ovarian hormones may influence the role of the endothelium in various physiological and pathophysiological conditions.
DNA Methylation Decreases in Aging But Not in Immortal Cells
Authors: Wilson Vincent L. , Jones Peter A.
Published: October 2006

When normal diploid fibroblasts from mice, hamsters, and humans were grown in culture, the 5-methylcytosine content of their DNA's markedly decreased. The greatest rate of loss of 5-methylcytosine residues was observed in mouse cells, which survived the least number of divisions. Immortal mouse cell lines had more stable rates of methylation.
Sex Differences in Dendritic Structure in the Preoptic Area of the Juvenile Macaque Monkey Brain
Authors: Ayoub David M. , Greenough William T. , Juraska Janice M.
Published: October 2006

Quantitative analysis of Golgi-stained neurons in the preoptic area of the brain of prepuberal
Macaca fascicularis
monkeys indicated structural differences between males and females. Neurons of males had more dendritic bifurcations and a higher frequency of spines. The bifurcation difference appeared in all cell types and was concentrated in the ventrolateral preoptic area. The spine difference was greatest in the central region of the preoptic area. No differences in gross measurements of this brain region were found. These results suggest that sexual dimorphism in the function of the monkey preoptic area may be based on differences in neuronal structure.
Hemoglobin Aggregation in Single Red Blood Cells of Sickle Cell Anemia
Authors: Nishio Izumi , Tanaka Toyoichi , Sun Shao-Tang , Imanishi Yuri , Ohnishi S. Tsuyoshi
Published: October 2006

A laser light scattering technique was used to observe the extent of hemoglobin aggregation in solitary red blood cells of sickle cell anemia. Hemoglobin aggregation was confirmed in deoxygenated cells. The light scattering technique can also be applied to cytoplasmic studies of any biological cell.
Pimozide Blocks Establishment But Not Expression of Amphetamine-Produced Environment-Specific Conditioning
Authors: Beninger Richard J. , Hahn Brenda L.
Published: October 2006

Animals with a history of receiving daily injections of +-amphetamine in a specific environment showed a placebo effect (enhanced activity) when injected with saline and placed there; control animals with similar but dissociated drug histories and experience with the test chamber failed to show the effect. The dopamine receptor blocker pimozide antagonized the establishment of conditioning. However, the same dose of pimozide, when given to previously conditioned animals on the placebo test day, failed to antagonize the expression of conditioned activity. Thus, during conditioning dopaminergic neurons mediated a change that subsequently influenced behavior even when dopaminergic systems were blocked. Although schizophrenia may be related to hyperfunctioning of dopamine, neuroleptic drugs, which block dopamine receptors on their first administration, do not have therapeutic effects for a number of days. The results of the pimozide experiments may resolve this paradox.
Accumulation of D-Aspartic Acid with Age in the Human Brain
Authors: Man Eugene H. , Sandhouse Mark E. , Burg Jonathan , Fisher George H.
Published: October 2006

An age-related accumulation of D-aspartic acid was detected in the white matter of ten normal brains from individuals aged 30 to 80 years. Gray matter showed no systematic increase in D-aspartic acid. The rate constant for D-aspartate formation in the brain is equal to the predicted value calculated for 37°C. Accumulation of the uncommon D-aspartate isomer in myelinated white matter implies that there is little or no turnover of this tissue, and this may have a bearing on dysfunction of the aging brain or on other diseases of myelin.
Eye Dominance Columns from an Isogenic Double-Nasal Frog Eye
Authors: Ide Charles F. , Fraser Scott E. , Meyer Ronald L.
Published: October 2006

Removing the posterior (temporal) two-thirds of the
Xenopus
eye bud produces a remaining fragment, which becomes round and grows to a normal adult size eye. Electrophysiological and anatomical analyses showed that each of the two halves of this eye projected across the entire optic tectum in mirror image (double-nasal) fashion, and that fibers from each half-eye sorted out to form eye dominance stripes on the tectum. That both halves of the mirror-symmetric map were derived from only one animal, and from only one side of the head, rules out global markers such as right versus left and histocompatibility differences as causing the formation of these stripes.
Magnesium Deficiency-Induced Spasms of Umbilical Vessels: Relation to Preeclampsia, Hypertension, Growth Retardation
Authors: Altura Burton M. , Altura Bella T. , Carella Anthony
Published: October 2006

Isolated umbilical arteries and veins, obtained from normal women at the end of pregnancy, were incubated in Krebs-Ringer bicarbonate solution and exposed to magnesium at concentrations ranging from 0 to 9.6 millimoles per liter. The basal tension of the vessels increased when magnesium was withdrawn and decreased when the concentration of magnesium was raised. Absence of magnesium in the medium significantly potentiated the contractile response of the vessels to bradykinin, angiotensin II, serotonin, and prostaglandin F
2α
. It appears that magnesium deficiency may be responsible for spasms of umbilical and placental vasculature. Our findings may provide a rationale for why magnesium sulfate is an effective therapy in preeclamptic syndromes in pregnant women.
Electrical Synapse Formation Depends on Interaction of Mutually Growing Neurites
Authors: Hadley Robert D. , Kater S. B. , Cohan Christopher S.
Published: October 2006

A neuron's competence to form electrical synapses depends on its growth status. Experiments in situ and in cell culture with identified neurons of the snail
Helisoma
demonstrate that active neurite outgrowth from both potential partners must be spatially and temporally coincident for electrical synapse formation to occur.
Accurate Visual Measurement of Three-Dimensional Moving Patterns
Authors: Lappin Joseph S. , Fuqua Mark A.
Published: October 2006

Human observers discriminated relative three-dimensional distances in simple patterns of motion parallax with an acuity similar to vernier acuity under comparable conditions. Accurate visual measures of three-dimensional distance can be derived from the structural invariance of patterns undergoing perspective transformations.
Naltrexone Modulates Tumor Response in Mice with Neuroblastoma
Authors: Zagon Ian S. , McLaughlin Patricia J.
Published: October 2006

Naltrexone, an opiate antagonist, had both stimulatory and inhibitory effects, depending on the dosage, on the growth of S20Y neuroblastoma in A/Jax mice. Daily injections of 0.1 milligram of naltrexone per kilogram of body weight, which blocked morphine-induced analgesia for 4 to 6 hours per day, resulted in a 33 percent tumor incidence, a 98 percent delay in the time before tumor appearance, and a 36 percent increase in survival time. Neuroblastoma-inoculated mice receiving 10 milligrams of naltrexone per kilogram, which blocked morphine-induced analgesia for 24 hours per day, had a 100 percent tumor incidence, a 27 percent reduction in the time before tumor appearance, and a 19 percent decrease in survival time. Inoculation of neuroblastoma cells in control subjects resulted in 100 percent tumor incidence within 29 days. These results show that naltrexone can modulate tumor response and suggest a role for the endorphin-opiate receptor system in neuro-oncogenic events.
A Cholinergic-Sensitive Channel in the Cat Visual System Tuned to Low Spatial Frequencies
Authors: Harding T. H. , Wiley R. W. , Kirby A. W.
Published: October 2006

Visually evoked responses to counterphased gratings were recorded from the cat visual cortex before and after physostigmine administration. Physostigmine markedly reduced the responses to low spatial frequencies, but minimally affected the response to high frequencies. This effect is considered cholinergic since it could be reversed by atropine. These results support at least a two-channel model of spatial frequency responsivity.
Myosin Phosphorylation and the Cross-Bridge Cycle in Arterial Smooth Muscle
Authors: Dillon Patrick F. , Aksoy Mark O. , Driska Steven P. , Murphy Richard A.
Published: October 2006

Phosphorylation of the 20,000-dalton light chain of myosin is closely correlated with cross-bridge cycling in arterial smooth muscle. Evidence is presented that dephosphorylation can produce an attached, noncycling cross-bridge (latch-bridge) which is responsible for the high economy of force maintenance in this tissue.
The Application of Transmittancy Measurements to Biochemistry
Authors: Schertz Frank M.
Published: October 2006

In a very brief way I have tried to show how absorption spectra have been intimately related to the development of our knowledge of chlorophyll. One hundred years ago Stokes discovered several laws that are very applicable to-day. For apparatus he used a boarded-up window, a slit in a plank, a lens and a prism. Instead of thinking how much we have accomplished with highly refined instruments we biochemists should rather humble ourselves by thinking how little use we have made of the instruments which you have so nobly perfected.
Tumor Anorexia: A Learned Food Aversion?
Authors: Bernstein Ilene L. , Sigmundi Ronald A.
Published: October 2006

Anorexia can occur when a specific diet is associated with a developing illness. The studies reported here show that the decline in food intake which accompanies tumor growth is accompanied by the development of aversions to the specific diet consumed during tumor growth. An immediate elevation in food consumption occurred when a novel diet was introduced. Therefore, the development of learned aversions to the specific diet eaten during tumor growth may be a causal factor in the development of tumor anorexia.
Erythroid Differentiation of Clonal Rauscher Erythroleukemia Cells in Response to Erythropoietin or Dimethyl Sulfoxide
Authors: Sytkowski Arthur J. , Salvado August J. , Smith Georgianna M. , McIntyre Carol J. , deBoth N. J.
Published: October 2006

Clonal lines of Rauscher erythroleukemia cells exhibited selective responses to two inducers of differentiation, erythropoietin and dimethyl sulfoxide. There were substantial quantitative differences between clones that responded to both inducers. Several clones differentiated only in response to erythropoietin. Erythropoietin stimulated cell proliferation and differentiation whereas dimethyl sulfoxide inhibited proliferation, suggesting dissimilar modes of action.
Intraspecific Evidence for the Function of Single and Double Cones in the Teleost Retina
Authors: Boehlert George W.
Published: October 2006

Retinal growth in young
Sebastes diploproa
involves the succession of three distinct cone patterns. Development of the final pattern with the loss of single cones occurs in close temporal association with a permanent migration from the surface to deep water. The results suggest that loss of single cones depends upon the change in environment and that the loss occurs through fusion to double elements.
Prolactin Synthesis by Human Chorion-Decidual Tissue: a Possible Source of Prolactin in the Amniotic Fluid
Authors: Golander Avraham , Hurley Thomas , Barrett Janet , Hizi Amnon , Handwerger Stuart
Published: October 2006

Explants of human chorion-decidual tissue obtained at delivery from normal, full-term pregnancies synthesize and secrete prolactin. This hormone is indistinguishable from pituitary prolactin by chromatographic, electrophoretic, immunologic, and receptor assay techniques. These results suggest that chorion-decidua may be the source of the large quantities of prolactin in amniotic fluid.
Effects of the Home Environment on Withholding Behaviors and Conditioning in Infant and Neonatal Rats
Authors: Smith Gregory J. , Spear Norman E.
Published: October 2006

Rats 16 days old received passive-avoidance training in the presence or absence of home litter cues. Rats trained in the context of home litter cues learned the passive avoidance reliably faster than rats trained in isolation. In the presence of home litter cues, 16-day-old rats also exhibited more adultlike spontaneous alternation. Pavlovian conditioning of rats trained at 2 days of age was studied in the presence and absence of conspecifics. These experiments suggest that deficiencies in inhibitory behaviors and conditioning associated with immaturity can be alleviated when the testing environment is made more similar to the home environment.
Biochemical Analysis of Human T Lymphocyte Differentiation Antigens T4 and T5
Authors: Terhorst Cox , van Agthoven Andre , Reinherz Ellis , Schlossman Stuart
Published: October 2006

Two major functionally distinct T cell subsets in man have been defined with heteroantiserums and monoclonal antibodies directed against stable cell surface antigens that appear during thymic ontogeny. A monoclonal antibody to T4 antigen (anti-T4) is reactive with the peripheral inducer T cell population while a monoclonal antibody to T5 antigen (anti-T5) is reactive with the cytotoxic and suppressor population. Immunoprecipitation and electrophoresis on sodium dodecyl sulfate polyacrylamide gel were used to show that on human thymocytes or peripheral T cells the T4 antigen is a single 62,000-dalton glycoprotein while the T5 antigen is a complex of two glycoproteins, one being 30,000 daltons and the other 32,000 daltons. Similar glycoproteins have been isolated with antibodies to murine Lyt 1 and Lyt 2,3 antigens. Both the antigens defining the phenotypes of inducer and suppressor populations in man and mouse are structurally homologous.
Mouse Immunoglobulin D: Messenger RNA and Genomic DNA Sequences
Authors: Tucker Philip W. , Liu Chih-Ping , Mushinski J. Frederic , Blattner Frederick R.
Published: October 2006

The molecular structure of a mouse immunoglobulin D from a plasmacytoma tumor and that of the normal mouse gene coding for immunoglobulin D are presented. The DNA sequence results indicate an unusual structure for the tumor δ chain in two respects: (i) Only two constant (C) region domains, termed Cδ1 and Cδ3 by homology considerations, are found; the two domains are separated by an unusual hinge region CδH that lacks cysteine residues and thus cannot provide the covalent cross-links between heavy chains typically seen in immunoglobulins. The two domains and hinge are all coded on separate exons. (ii) At the carboxyl end of the δ chain there is a stretch of 26 amino acids that is coded from an exon located 2750 to 4600 base pairs downstream from the rest of the gene. Analogy with immunoglobulin M suggests that this distally coded segment CδDC may have a membrane-binding function; however, it is only moderately hydrophobic. A fifth potential exon (CδAC), located adjacent to the 3′ (carboxyl) end of Cδ3, could code for a stretch of 49 amino acids. The tumor's expression of the δ gene may be aberrant, but the simplest interpretation would be that this tumor expresses one of the several biologically significant forms of the δ chain.
Acoustic Responses After Total Destruction of the Cochlear Receptor: Brainstem and Auditory Cortex
Authors: Cazals Yves , Aran Jean-Marie , Erre Jean-Paul , Guilhaume Anne
Published: October 2006

Acoustically evoked neural activity has been recorded from the brainstem and auditory cortex of guinea pigs after complete destruction of the organ of Corti by the aminoglycosidic antibiotic amikacin. These responses to sound differ in important respects from the evoked potentials normally recorded from the auditory pathways. At the brainstem level they resemble the potentials reported by others after stimulation of the vestibular nerve.
Intracellularly Injected Cobaltous Ions Accumulate at Synaptic Densities
Authors: Phillips Christine E.
Published: October 2006

Physiologically identified neurons in the locust were iontophoretically injected with a mixture of cobaltous and potassium ions. After being fixed for electron microscopy, 2.5-micrometer sections of the epoxy-embedded ganglia were intensified with silver. The intensified material was resectioned and examined in the electron microscope. The cobalt-silver precipitate appeared as discrete densities. Localized accumulations of the precipitate were seen within the injected cell along the neuronal membranes and especially at synapses. Location and recognition of the stained neuron in the electron microscope was facilitated by the tendency of the cobaltous ions to aggregate at the synaptic sites.
Mutations in a Nonessential Viral Gene Permit Bacteriophage T4 to Form Plaques on
Escherichia coli
valS

ts

relA
Authors: Marchin George L.
Published: October 2006

During viral development bacteriophage T4 modifies the valyl-transfer RNA synthetase of its host
Escherichia coli
, but the function of the modification has remained elusive. A strain of
Escherichia coli
has now been identified which is nonpermissive for wild-type bacteriophage T4, but permissive for bacteriophage mutants impaired in the modification reaction. A comparison with other bacteria suggests that nonpermissiveness is due to synthesis of a thermolabile valyl-transfer RNA synthetase and relaxed control of RNA accumulation.
Comparison of the Nucleic Acid Sequence of Anglerfish and Mammalian Insulin mRNA's from Cloned cDNA's
Authors: Hobart Peter M. , Shen Lu-Ping , Crawford Robert , Pictet Raymond L. , Rutter William J.
Published: October 2006

Anglerfish (
Lophius americanus
) insulin complementary DNA was cloned in bacterial plasmids, and its sequence was determined. Fish insulin messenger RNA is larger (1.5 times) than the messenger RNA encoding mammalian (rat and human) insulin, in part because of a larger C peptide (an additional six amino acids or 18 nucleotides in length) but mainly because of increases in the 5′ and 3′ untranslated regions. Comparison of the fish, rat, and human insulin messenger RNA (from the complementary DNA) reveals that, in addition to the regions coding for the A and B peptides, sequence conservation is limited to a segment within the 5′ untranslated region which may be involved in ribosomal binding, two small segments of the signal peptide, and two stretches of sequence in the 3′ untranslated region.
Vertebrate Cell Cycle Modulates Infection by Protozoan Parasites
Authors: Dvorak James A. , Crane Mark St. J.
Published: October 2006

Synchronized HeLa cell populations were exposed to
Trypanosoma cruzi
or
Toxoplasma gondii
, obligate intracellular protozoan parasites that cause Chagas' disease and toxoplasmosis, respectively, in humans. The ability of the two parasites to infect HeLa cells increased as the HeLa cells proceeded from the G
1
phase to the S phase of their growth cycle and decreased as the cells entered G
2
-M. Characterization of the S-phase cell surface components responsible for this phenomenon could be beneficial in the development of vaccines against these parasitic diseases.
Insulin Stimulates the Phosphorylation of the 95,000-Dalton Subunit of Its Own Receptor
Authors: Kasuga Masato , Karlsson F. Anders , Kahn C. Ronald
Published: October 2006

Cultured human lymphocytes and rat hepatoma cells were labeled with [
32
P]orthophosphate and the insulin receptor subunits identified by immunoprecipitation and sodium dodecyl sulfate-gel electrophoresis. In both cell types the 95,000-dalton (β) subunit of the insulin receptor was selectively phosphorylated. Phosphorylation was specifically stimulated by insulin in a dose-dependent fashion after 1 and 15 minutes of hormone treatment, whereas human growth hormone was without effect. This phosphorylation may be a very early event in insulin action.
Inactivation of a Diol Epoxide by Dihydrodiol Dehydrogenase But Not by Two Epoxide Hydrolases
Authors: Glatt H. R. , Cooper C. S. , Grover P. L. , Sims P. , Bentley P. , Merdes M. , Waechter F. , Vogel K. , Guenthner T. M. , Oesch F.
Published: October 2006

The mutagenicity of
r
-8,
t
-9-dihydroxy-
t
-10, 11-oxy-8,9,10,11-tetrahydrobenz[
a
]anthracene (BA-8,9-diol 10,11-oxide) toward
Salmonella typhimurium
TA 100 is not decreased by the presence of large amounts of highly purified microsomal or cytosolic epoxide hydrolase. However, highly purified dihydrodiol dehydrogenase inactivates this diol epoxide, which is a major DNA-binding metabolite of benz[
a
]anthracene. The K-region epoxide, benz[
a
]anthracene 5,6-oxide (BA 5,6-oxide) is efficiently inactivated by microsomal epoxide hydrolase, is much less readily inactivated by cytosolic epoxide hydrolase, and is not inactivated by dihydrodiol dehydrogenase. This inactivation of a diol epoxide by dihydrodiol dehydrogenase points to a new significance of this enzyme and a new level of control for diol epoxides.
Supraoptic Nucleus of the Brattleboro Rat Has an Altered Afferent Noradrenergic Input
Authors: Schöler Jan , Sladek John R.
Published: October 2006

The distribution of fluorescent varicosities in the supraoptic nucleus of Brattleboro rats was compared to that in normal rats. The Brattleboro rat, which is characterized by a genetic absence of vasopressin, had fewer fluorescent varicosities in apposition to the vasopressin-deficient perikarya. The oxytocin-producing neurons in the same nucleus were hyperinnervated. These data suggest that the target neuron peptide (vasopressin) is necessary for the maintenance of normal noradrenergic innervation patterns.
Prenatal Exposure to Prednisone in Humans and Animals Retards Intrauterine Growth
Authors: Reinisch June MacHover , Simon Neal G. , Karow William G. , Gandelman Ronald
Published: October 2006

Prednisone treatment for infertility and subsequent pregnancy maintenance in humans resulted in a significant decrease in the birth weight of full-term infants and a marked increase in the percentage of newborn infants weighing 2500 grams or less, that is, "light for dates" in comparison to control offspring. A parallel experiment with mice indicated that the reduction of birth weight was caused by exposure to corticosteroids rather than to maternal disease or malfunction.
Chimpanzee Problem-Solving: A Test for Comprehension
Authors: Premack David , Woodruff Guy
Published: October 2006

An adult chimpanzee was shown videotaped scenes of a human actor struggling with one of eight problems and was then shown two photographs, one of which depicted an action or an object (or both) that could constitute a solution to the problem. On seven of the eight problems, the animal consistently chose the correct photograph. This test problem-solving comprehension permits the animal's knowledge about problem-solving—its ability to infer the nature of problems and to recognize potential solutions to them—to be examined.
How Do We Avoid Confounding the Direction We Are Looking and the Direction We Are Moving?
Authors: Regan D. , Beverley K. I.
Published: October 2006

Contrary to a previous assumption, the center of the expanding pattern of visual flow is not generally useful as an aid in judging the direction of self motion since its direction depends on the direction of gaze. For some visual environments, however, the point of maximum rate of change of magnification in the retinal image coincides with the direction of self motion, independently of the direction of gaze. This visual indicator could be used to judge the direction of self motion.
Primary Changes of Membrane Currents During Retention of Associative Learning
Authors: Alkon Daniel L. , Lederhendler Izja , Shoukimas Jonathan J.
Published: October 2006

A single identified neuron was repeatedly isolated by axotomy from the central nervous system of the nudibranch mollusk
Hermissenda crassicornis
. An early voltage-dependent outward K
+
current of this neuron was reduced and more rapidly inactivated for animals previously trained with paired but not randomized light and rotation. Since this current change can affect interneuron and motorneuron output via known synaptic pathways, it helps explain a long-lasting behavioral change that shows the defining features of vertebrate associative learning.
Optical Disk Technology and Information
Authors: Goldstein Charles M.
Published: October 2006

The optical video disk, spawned by the home entertainment industry, and its counterpart, the optical digital disk, both hold great promise for information storage and retrieval and the scientific enterprise. Optical digital disks for computer mass storage are currently under development by many firms. In addition, efforts are under way to allow encoding of digital information on video disks. This is desirable as an inexpensive publication medium for machine-readable data as well as a means of obtaining both video and digital information on one disk. Potential applications of this technology include inexpensive on-line storage, random access graphics to complement on-line information systems, hybrid network architectures, office automation systems, and archival storage.
Alzheimer's Disease and Senile Dementia: Loss of Neurons in the Basal Forebrain
Authors: Whitehouse PJ , Price DL , Struble RG , Clark AW , Coyle JT , DeLong Mahlon R.
Published: October 2006

Recent evidence indicates that the nucleus basalis of Meynert, a distinct population of basal forebrain neurons, is a major source of cholinergic innervation of the cerebral cortex. Postmortem studies have previously demonstrated profound reduction in the presynaptic markers for cholinergic neurons in the cortex of patients with Alzheimer's disease and senile dementia of the Alzheimer's type. The results of this study show that neurons of the nucleus basalis of Meynert undergo a profound (> 75 percent) and selective degeneration in these patients and provide a pathological substrate of the cholinergic deficiency in their brains. Demonstration of selective degeneration of such neurons represents the first documentation of a loss of a transmitter-specific neuronal population in a major disorder of higher cortical function and, as such, points to a critical subcortical lesion in Alzheimer's patients.
Norethisterone, a Major Ingredient of Contraceptive Pills, Is a Suicide Inhibitor of Estrogen Biosynthesis
Authors: Osawa Yoichi , Yarborough Carol , Osawa Yoshio
Published: October 2006

Norethisterone (17α-ethynyl-19-nortestosterone) is an effective irreversible inhibitor of estrogen synthetase (aromatase), the enzyme responsible for the conversion of androgens to estrogens, even at a 2 × 10
-6
molar concentration. This irreversible inactivation, which is directed toward the active site of aromatase and requires the cofactor-reduced nicotinamide adenine dinucleotide phosphate, is both time- and concentration-dependent. Ethisterone (17α-ethynyltestosterone), in contrast, is not a suicide inhibitor of aromatase even at concentrations of 10
-4
molar.
Hydrolysis of Nerve Gas by Squid-Type Diisopropyl Phosphorofluoridate Hydrolyzing Enzyme on Agarose Resin
Authors: Hoskin Francis C. G. , Roush Allan H.
Published: October 2006

An enzyme purified from squid nerve that hydrolyzes the cholinesterase inhibitor diisopropyl phosphorofluoridate (DFP) has now been coupled to agarose beads. A column of this agarose-DFPase hydrolyzes the nerve gas 1,2,2-trimethylpropyl methylphosphonofluoridate (Soman). Although the more inhibitory of the four diastereoisomers of Soman are hydrolyzed least rapidly, a column of sufficient length will accomplish 95 percent hydrolysis whether measured by fluoride release or loss of cholinesterase-inhibiting power. The results suggest a means for detoxifying unwanted chemical warfare agents.
Spiroplasmas: Cultivation in Chemically Defined Medium
Authors: Chang Chung-Jan , Chen Tseh An
Published: October 2006

A chemically defined medium, CC-494, supports the cultivation in vitro of several spiroplasmas belonging to three distinct serogroups. Medium CC-494 supports the growth of flower spiroplasmas FS 23-6 and FS SR-3 and of honey bee spiroplasma HBS AS-576. The maximal populations of the two flower spiroplasmas and honey bee spiroplasma are comparable to those cultured in the undefined medium C-3G. The growth rate for all three spiroplasmas is slower in the defined medium.
N-Acetylation Regulates the Behavioral Activity of α-Melanotropin in a Multineurotransmitter Neuron
Authors: O'Donohue Thomas L. , Handelmann Gail E. , Miller Russell L. , Jacobowitz David M.
Published: October 2006

A multineurotransmitter neuronal system that synthesizes and secretes both acetylated and deacetylated forms of α-melantropin and β-endorphin is present in rat and human brain. TheN-acetylated from of α-melanotropin had more potent behavioral effects than the deacetylated α-melanotropin. In the case of β-endorphin, however, the deacetylated form has been shown to be more potent than the acetylated form. EnzymaticN-acetylation appears to be an important regulatory process for modulating the behavioral activity of peptides secreted from the opiomelanotropinergic multineurotransmitter neuron.
Rapid Electronic Autofluorography of Labeled Macromolecules on Two-Dimensional Gels
Authors: Davidson J. B. , Case A. L.
Published: October 2006

The feasibility of electronically locating and measuring tritium-labeled macromolecules directly on dried electrophoretic gels has been demonstrated. This new procedure eliminates the usual long film exposure in autofluorography and the attendant delay in processing and data reduction. An image intensifier and electronic camera tube are used to integrate the light produced by the tritium interaction with a scintillator incorporated in the gel. Preliminary results show that, compared to film, the exposure is reduced 100 to 1000 times. The response to low activity levels is improved, and spatial resolution is maintained. A proposed instrument could be used for measuring other isotopes as well as fluorescent and visible stains.
Computer-Generated Schematic Diagrams of Protein Structures
Authors: Lesk Arthur M. , Hardman Karl D.
Published: October 2006

Computer-generated pictures are essential for studying and comparing the structures of proteins that have been solved by x-ray crystallography. Stereoscopic pairs produced by a computer program are particularly useful in providing an intelligible portrayal of the molecular topology.
Fluorides and the Changing Prevalence of Dental Caries
Authors: Leverett Dennis H.
Published: October 2006

Community water fluoridation and individual use of fluorides have brought about a marked reduction in the prevalence of dental caries in the United States during the past 35 years. There is evidence that the prevalence of caries is declining in communities with unfluoridated water as well as in those with fluoridated water. This phenomenon may be related to an increase of fluoride in the food chain, especially from the use of fluoridated water in food processing, increased use of infant formulas with measurable fluoride content, and even unintentional ingestion of fluoride dentifrices. This trend should encourage reevaluation of research priorities and previously accepted standards for optimal fluoride use.
Controlled Drinking by Alcoholics? New Findings and a Reevaluation of a Major Affirmative Study
Authors: Pendery Mary L. , Maltzman Irving M. , West L. Jolyon
Published: October 2006

Controlled drinking has recently become a controversial alternative to abstinence as an appropriate treatment goal for alcoholics. In this study we reexamine the evidence underlying a widely cited report by Sobell and Sobell of successful controlled drinking by a substantial proportion of
gamma
(physically dependent) alcoholic subjects in a behavior therapy experiment. A review of the evidence, including official records and new interviews, reveals that most subjects trained to do controlled drinking failed from the outset to drink safely. The majority were rehospitalized for alcoholism treatment within a year after their discharge from the research project. A 10-year follow-up (extended through 1981) of the original 20 experimental subjects shows that only one, who apparently had not experienced physical withdrawal symptoms, maintained a pattern of controlled drinking; eight continued to drink excessively—regularly or intermittently—despite repeated damaging consequences; six abandoned their efforts to engage in controlled drinking and became abstinent; four died from alcohol-related causes; and one, certified about a year after discharge from the research project as gravely disabled because of drinking, was missing.
Lung Fibrosis and Emphysema: Divergent Responses to a Common Injury?
Authors: Niewoehner Dennis E. , Hoidal John R.
Published: October 2006

Cadmium chloride, administered intratracheally to golden Syrian hamsters, causes an acute lung injury which evolves into a lesion with functional and morphological features of diffuse fibrosis. With simultaneous feeding of a lathyrogen, β-aminoproprionitrile, this same injury evolves into functional and morphological changes of bullous emphysema. These results suggest that the same lung injury might result in either fibrosis or emphysema, connective tissue synthesis during the healing phase being the critical determinant.
Intraneuronal Aluminum Accumulation in Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia of Guam
Authors: Perl Daniel P. , Gajdusek D. Carleton , Garruto Ralph M. , Yanagihara Richard T. , Gibbs Clarence J.
Published: October 2006

Scanning electron microscopy with energy-dispersive x-ray spectrometry was used to analyze the elemental content of neurofibrillary tangle (NFT)-bearing and NFT-free neurons within the Sommer's sector (H
1
region) of the hippocampus in Guamanian Chamorros with amyotrophic lateral sclerosis and parkinsonism-dementia and in neurologically normal controls. Preliminary data indicate prominent accumulation of aluminum within the nuclear region and perikaryal cytoplasm of NFT-bearing hippocampal neurons, regardless of the underlying neurological diagnosis. These findings further extend the association between intraneuronal aluminum and NFT formation and support the hypothesis that environmental factors are related to the neurodegenerative changes seen in the Chamorro population.
The Perception of Biological Motion by Human Infants
Authors: Fox Robert , McDaniel Cynthia
Published: October 2006

When a small number of lights are placed on the limbs and joints of a moving human (or animal), the motions of the lights (biological motion) are sufficient to enable adult observers to perceive immediately the activity of the human. This perception of biological motion has been hypothesized to be an intrinsic capacity of the visual system. The results of this experiment, which demonstrate that infants 4 to 6 months of age exhibit a preference for biological motion patterns, support that hypothesis.
Sugar Infusion Can Enhance Feeding
Authors: Geiselman Paula J. , Novin Donald
Published: October 2006

An investigation was made of the role of glucose in the regulation of hunger and satiety in the rabbit. Glucose, when infused intraduodenally at a low rate (1 milliliter per minute), produced a decrease in food intake. However, when glucose was infused into the duodenum at a high rate (3 milliliters per minute), the rabbits nearly doubled their food intake during the first half-hour after infusion. It is hypothesized that the rapid arrival of glucose in the duodenum may produce hunger.
Bronchial Hyperreactivity Associated with Tracheal Gangliosides
Authors: Banerjee Dipak Kumar
Published: October 2006

Gangliosides, which are membrane constituents of animal cells, may be altered under various conditions that cause change in metabolism. In this study, gangliosides from tracheal and lung tissues were extracted and measured as a function of bronchial hyperreactivity in a guinea pig model of bronchial asthma. When plotted logarithmically, the data showed that tracheal gangliosides decreased with an increase in airway reactivity index, suggesting a linear relation between them. Differential analysis of tracheal gangliosides in the acute stage of bronchial hyperreactivity indicates accumulation of polysialogangliosides. These data support the hypothesis that tracheal gangliosides are intimately involved in the development of bronchial asthma.
A Specific and Enduring Improvement in Visual Motion Discrimination
Authors: Ball Karlene , Sekuler Robert
Published: October 2006

Training improves the ability of human observers to discriminate between two similar directions of motion. This gradual improvement is specific to the direction on which an observer is trained, and it endures for several months. Improvement does not affect motion perception generally, nor does it depend on recognition of details of the movement.
The Bimodal Perception of Speech In Infancy
Authors: Kuhl Patricia K. , Meltzoff Andrew N.
Published: October 2006

Infants 18 to 20 weeks old recognize the correspondence between auditorially and visually presented speech sounds, and the spectral information contained in the sounds is critical to the detection of these correspondences. Some infants imitated the sounds presented during the experiment. Both the ability to detect auditory-visual correspondences and the tendency to imitate may reflect the infant's knowledge of the relationship between audition and articulation.
Simulating Amnesic Symptoms in Normal Subjects
Authors: Graf Peter , Mandler George , Haden Patricia E.
Published: October 2006

Patients with organic brain damage resulting in anterograde amnesia cannot recall a list of words, but when given the first three letters of each word, they complete these word stems with words from the list. We simulated this phenomenon in normal subjects who examined the list words for vowels while ignoring their semantic component. The subjects produced the list words when completing the word stems although they could not recall the words.
Monoclonal Antibodies in the Lymphatics: Toward the Diagnosis and Therapy of Tumor Metastases
Authors: Weinstein John N. , Parker Robert J. , Keenan Andrew M. , Dower Steven K. , Morse Herbert C. , Sieber Susan M.
Published: October 2006

Monoclonal antibodies subcutaneously injected into mice track to regional lymph nodes and specifically label target cells there. The lymphatic route of administration can be expected to provide much higher sensitivity, higher target-to-background ratio, faster localization, and lower toxicity than the intravenous route when the aim is to diagnose or treat tumor metastases or lymphoma in the lymph nodes.
Entry of Insulin Into Human Cultured Lymphocytes: Electron Microscope Autoradiographic Analysis
Authors: Goldfine I. D. , Jones A. L. , Hradek G. T. , Wong K. Y. , Mooney J. S.
Published: October 2006

Electron microscope autoradiographs were prepared of IM-9 human cultured lymphocytes incubated with iodine-125-labeled insulin. With the use of [
125
I]insulin and Ilford L-4 emulsion, the technique had a resolution half-distance of approximately 0.085 micrometer. Autoradiographs revealed a time-dependent entry of insulin into the cell interior that was maximal after 30 minutes of incubation. At this time point nearly 40 percent of the [
125
I]insulin was in the interior of the cell at a distance 1 micrometer or greater from the plasma membrane. Grain distribution and volume density analyses revealed that the intracellular insulin was concentrated in the endoplasmic reticulum and nuclear membrane.
Memory Impairment in Korsakoff's Psychosis: A Correlation with Brain Noradrenergic Activity
Authors: McEntee William J. , Mair Robert G.
Published: October 2006

The concentration of the primary brain metabolite of norepinephrine is diminished in the lumbar spinal fluid of patients with Korsakoff's syndrome. The extent of its reduction is significantly correlated with measures of memory impairment for individual patients. These data suggest that the memory disorder of Korsakoff's syndrome may result from damage to ascending noradrenergic pathways by the diencephalic and brainstem lesions associated with this disease.
Sperm-Egg Interaction: Evidence for Boar Sperm Plasma Membrane Receptors for Porcine Zona Pellucida
Authors: Peterson Rudolph N. , Russell Lonnie , Bundman Donna , Freund Matthew
Published: October 2006

Freshly ejaculated, noncapacitated boar sperm bind rapidly and in large numbers to pig egg zona pellucida in vitro. In the present study, the number of sperm bound decreased sharply when sperm motility was lowered by energy poisons or by reducing the temperature. Highly motile sperm from humans, guinea pigs, and rats, added at concentrations ten times higher than control sperm, did not bind to the porcine zona. At the same high concentration, a small number of hamster and bull sperm bound to the zona. Binding of boar sperm to the zona pellucida was blocked almost completely by diluted whole antiserum to sperm plasma membranes and by univalent (Fab) antibody to these membranes. When antibody to sperm plasma membrane was first absorbed with plasma membrane vesicles, sperm binding was not inhibited. These results provide direct evidence for the existence of sperm plasma membrane receptors for the zona pellucida of the pig.