bluuebunny/crossref_metadata_2025 huggingface dataset:
Elastin Fragments Attract Macrophage Precursors to Diseased Sites in Pulmonary Emphysema
Authors: Hunninghake G. W. , Davidson J. M. , Rennard S. , Szapiel S. , Gadek J. E. , Crystal R. G.
Published: October 2006

This study suggests one mechanism by which alveolar macrophages accumulate in the lung in pulmonary emphysema: elastin fragments generated at the diseased sites are potent chemoattractants for monocytes, the precursors of the macrophages. The most chemotactic elastin fragments have a molecular weight between 10,000 and 50,000 and are active at concentrations as low as 3 nanograms per milliliter. By comparison, elastin fragments with higher molecular weights and desmosines are active only at concentrations greater than 0.3 microgram per milliliter. In addition, preincubation of monocytes with the 10,000- to 50,000-dalton elastin impairs the ability of the cells to migrate toward elastin fragments but not toward activated serum. Fragments of tropoelastin are not chemotactic for monocytes. Because elastin, but not tropoelastin, contains lysyl-derived cross-links, these structures may be the active chemotactic site on the elastin fragments.
Didemnins: Antiviral and Antitumor Depsipeptides from a Caribbean Tunicate
Authors: Rinehart Kenneth L. , Gloer James B. , Hughes Robert G. , Renis Harold E. , McGovren J. Patrick , Swynenberg Everett B. , Stringfellow Dale A. , Kuentzel Sandra L. , Li Li H.
Published: October 2006

Extracts of samples of a Caribbean tunicate (ascidian, sea squirt) of the family Didemnidae inhibit in vitro at low concentrations the growth of DNA and RNA viruses as well as L1210 leukemic cells. The active compounds isolated from the tunicate, didemnins A, B, and C, are depsipeptides, and didemnin B (a derivative of didemnin A) is the component active at the lowest concentration in inhibiting viral replication in vitro and P388 leukemia in vivo.
Inferotemporal Neurons Distinguish and Retain Behaviorally Relevant Features of Visual Stimuli
Authors: Fuster Joaquin M. , Jervey John P.
Published: October 2006

Single-cell activity was recorded in the inferotemporal cortex of monkeys performing a task that requires perception and temporary retention of colored stimuli. Many cells reacted differentially to the stimuli. By changing the relevance of certain features of compound stimuli, it was found that the reactions of some cells to color depend critically on whether or not the task demands that the animal pay attention to color. A substantial number of cells showed color-dependent differences in frequency of discharge during the retention periods of the task. The temporal characteristics of differential discharge and its dissolution when memory is no longer required indicate that the cells that display it are involved in retaining visual information.
Peripherally Administered Reduced Pterins Do Enter the Brain
Authors: Kapatos Gregory , Kaufman Seymour
Published: October 2006

The content of tetrahydrobiopterin in rat brain was doubled by peripherally administered tetrahydrobiopterin, with the natural
1
diastereoisomer more effective than the unnatural
d
configuration. The model pteridine, 6-methyltetrahydropterin was ten times more efficient than tetrahydrobiopterin in crossing the blood-brain barrier, and striatal concentrations of 6-methyltetrahydropterin remained elevated for 2 hours, declining with a half-life of 3 hours. While no evidence for a specific uptake mechanism for concentrating 6-methyltetrahydropterin in cells containing tetrahydrobiopterin was detected, the pterin was found in its presumed site of action, the nerve terminal. Replacement therapy with reduced pterins may therefore be effective in the treatment of the neurological disorders associated with the variant forms of hyperphenylalaninemia that result from defects in the biosynthesis or metabolism of tetrahydrobiopterin within the central nervous system.
Parasitism and Behavioral Dominance Among Male Mice
Authors: Freeland W. J.
Published: October 2006

Infestations by the nematode
Heligmosomoides polygyrus
can prevent adult male mice from becoming behaviorally dominant. The effect is dose-dependent and is more likely to influence the development of dominance than to disrupt existing dominance relationships. Doses capable of exerting this effect are not lethal and do not affect weight.
Ethanol Reveals Novel Mercury Detoxification Step in Tissues
Authors: Dunn Jan Dotzler , Clarkson Thomas W. , Magos Laszlo
Published: October 2006

Volatile mercury was produced de novo by mouse tissue homogenates that contained mercuric ions. Ethanol stimulated the release of tissue mercury into the vapor phase, and the mechanism appears to be an inhibition of reoxidation of volatile mercury. Components responsible for mercury volatilization are heat-labile. The highest volatilizing activity in the liver is associated with the soluble fraction obtained after centrifugation at 105,000g.
Spatial Localization After Strabismus Surgery: Evidence for Inflow
Authors: Steinbach Martin J. , Smith David R.
Published: October 2006

Strabismics pointed to targets (without sight of the hand) before and again after surgery that altered the position of the deviating eye in its orbit. Patients having this surgery for the first time were able to use proprioceptively derived information about the surgically altered eye position. In contrast, patients who had similar operations, but on muscles that had been operated on one or more times in the past, were apparently deprived of this information. The important afference may be supplied by the tendon organs.
Cilium Length: Influence on Neural Tonotopic Organization
Authors: Turner Robert G. , Muraski Anthony A. , Nielsen Donald W.
Published: October 2006

Previous studies have suggested that variations in the length of the hair cell cilia contribute to auditory nerve fiber tuning and tonotopic organization. In the granite spiny lizard, cilium length and the tonotopic organization of nerve fibers are correlated: fiber characteristic frequency increases as cilium length decreases. This results in an increasing fiber characteristic frequency in both the apical and basal direction. a pattern not previously seen in any vertebrate.
Myelinated Nociceptive Afferents Account for the Hyperalgesia That Follows a Burn to the Hand
Authors: Meyer Richard A. , Campbell James N.
Published: October 2006

Monkeys and human subjects were exposed to a series of thermal stimuli before and after a 53°C, 30-second burn to the glabrous skin of the hand. The responses of C- and A-fiber nociceptive afferents in the monkeys and subjective responses by the humans were compared. The burn resulted in increased sensitivity of the A fibers, decreased sensitivity of the C fibers, and increased pain sensibility (hyperalgesia) in the human subjects.
The Complement System of the Nurse Shark: Hemolytic and Comparative Characteristics
Authors: Jensen Joerg A. , Festa Elena , Smith David S. , Cayer Marilyn
Published: October 2006

The complement system of the nurse shark was investigated. Six functionally pure components were isolated from a single serum sample. Sequential reactions of the components with sensitized sheep erythrocytes resulted in membrane lesions indistinguishable from the "holes" caused by guinea pig complement.
Ganglioside Stimulation of Axonal Sprouting in Vitro
Authors: Roisen Fred J. , Bartfeld Harry , Nagele Robert , Yorke Glee
Published: October 2006

Bovine brain gangliosides were applied to primary and established neuronal cultures to examine the role of gangliosides in neuronal development. Media containing gangliosides enhanced the degree of axonal elongation exhibited by sensory ganglia neurons and increased the length and number of Neuro-2a neuroblastoma cell processes. Ganglioside-supplemented media caused a twofold increase in ornithine decarboxylase activity in both culture systems. These experiments suggest that gangliosides function as acceptor molecules for growth-promoting substances in embryonic and tumor-derived neurons.
In Vivo Carbon-13 Nuclear Magnetic Resonance Studies of Mammals
Authors: Alger J. R. , Sillerud L. O. , Behar K. L. , Gillies R. J. , Shulman R. G. , Gordon R. E. , Shaw D. , Hanley P. E.
Published: October 2006

Natural abundance carbon-13 nuclear magnetic resonances (NMR) from human arm and rat tissues have been observed in vivo. These signals arise primarily from triglycerides in fatty tissue. Carbon-13 NMR was also used to follow, in a living rat, the conversion of C-1-labeled glucose, which was introduced into the stomach, to C-1-labeled liver glycogen. The carbon-13 sensitivity and resolution obtained shows that natural abundance carbon-13 NMR will be valuable in the study of disorders in fat metabolism, and that experiments with substrates labeled with carbon-13 can be used to study carbohydrate metabolism in vivo.
Female Sex Pheromone in the Skin and Circulation of a Garter Snake
Authors: Garstka William R. , Crews David
Published: October 2006

Serums and extracts of tissues from the female garter snake (
Thamnophis sirtalis parietalis
) each act as a pheromone and elicit male courtship behavior when applied to the back of another male. Since pheromonal activity is present in yolk and liver tissue of untreated females and can be induced with estrogen treatment in the serums and livers of males, the pheromone may be associated with the circulating yolk lipoprotein, vitellogenin.
Women Scientists and Engineers: Trends in Participation
Authors: Vetter Betty M.
Published: October 2006

Women have made tremendous strides in educational attainment in science and engineering over the past decade, increasing their proportion of doctorate awards in these fields from 7 percent in 1965 to 23 percent in 1980. But they still have higher unemployment rates and lower salaries than men in all fields of science and engineering, at all degree levels, and at all levels of experience; and the disparities between men and women widen with higher degree levels and with years of experience. Graduate enrollments indicate continuing increases over at least the next several years in degree awards to women, but their access to equal employment and advancement opportunities is not assured.
Vesicle Targeting: Timed Release and Specificity for Leukocytes in Mice by Subcutaneous Injection
Authors: Mauk Marcia R. , Gamble Ronald C. , Baldeschwieler John D.
Published: October 2006

When unilamellar vesicles were administered subcutaneously in mice, the half-time for the destruction of the vesicles varied from 12 to 600 hours, depending on their composition. The vesicles tested consisted of distearoyl phosphatidylcholine, cholesterol, and certain sugar and amino-sugar derivatives of cholesterol. Vesicles with amino-sugar derivatives showed the greatest longevity and became localized with high specificity in aggregates of polymorphonuclear leukocytes. A substantial delay between the time that the vesicles broke open and the time that labels contained in the vesicles were excreted suggests that the vesicles undergo endocytosis before destruction.
Human Fibroblast Interferon: Amino Acid Analysis and Amino Terminal Amino Acid Sequence
Authors: Knight E. , Hunkapiller M. W. , Korant B. D. , Hardy R. W. , Hood L. E.
Published: October 2006

The purification of human fibroblast interferon has been simplified to a two-step procedure consisting of affinity chromatography on Blue Sepharose and sodium dodecyl sulfate polyacrylamide gel electrophoresis. A preliminary amino acid composition and the sequence of the 13 amino-terminal residues of homogeneous interferon prepared by this method is reported.
Laminar Organization of Thalamic Projections to the Rat Neocortex
Authors: Herkenham Miles
Published: October 2006

Nerve fibers transmitting information from the thalamus to the cerebral cortex may be classified according to their major cortical layers of termination. (i) One class consists of inputs from thalamic relay nuclei for vision, audition, and somesthesis to layer IV, layer III, or both. In contrast, autoradiographic studies of projections from other thalamic nuclei reveal strikingly different patterns of termination: (ii) layer VI (or layer V, or both) is the target of fibers from the intralaminar nuclei, and (iii) layer I is the target for fibers from the ventromedial and magnocellular medial geniculate nuclei. (iv) The remaining class is typified by termination both in layer I and in additional layers that depend on the cortical area in which the terminations are found. The data demonstrate that convergent thalamic inputs to a given cortical area are usually not confluent within a layer and provide a new frame-work for categorizing thalamic nuclei.
Electrophysiological Signs of Split-Second Decision-Making
Authors: Woods David L. , Hillyard Steven A. , Courchesne Eric , Galambos Robert
Published: October 2006

When young adults detected auditory stimuli at split-second intervals, different components of the event-related brain potentials showed markedly different speeds of recovery. The P
3
component (latency 300 to 350 milliseconds) was fully recovered at intervals of less than 1.0 second, while the N
1
—P
2
components (latencies 100 to 180 milliseconds) were markedly attenuated with stimulus repetition even at longer interstimulus intervals. Thus, the N
1
—P
2
recovers much more slowly than a subject's ability to evaluate signals, whereas the P
3
appears to be generated at the same high rates as the decision processes with which it is associated.
Binocularity in the Cat Visual Cortex Is Reduced by Sectioning the Corpus Callosum
Authors: Payne B. R. , Elberger Andrea J. , Berman Nancy , Murphy E. Hazel
Published: October 2006

In the normal cat, most cells in area 17 can be binocularly driven. Sectioning the corpus callosum results in a significant reduction in binocularly driven cells. Normal binocular vision is thus dependent on the corpus callosum.
Artificial Sweetener Use and Bladder Cancer: A Case-Control Study
Authors: Wynder Ernst L. , Stellman Steven D.
Published: October 2006

In a case-control study of 302 male and 65 female bladder cancer patients and an equal number of other patients matched to them in age, sex, hospital, and hospital-room status, no association was found between use of artificial sweeteners or diet beverages and bladder cancer. No dose-response was observed with respect to quantity or duration of use or the two combined. No evidence was found to suggest that artificial sweeteners or diet beverages promote the tumorigenic effect of tobacco smoking. Artificial sweetener and diet beverage use strongly reflected socioeconomic status among controls with various diagnoses.
Interspecific Chimeras in Mammals: Successful Production of Live Chimeras Between
Mus musculus
and
Mus caroli
Authors: Rossant J. , Frels W. I.
Published: October 2006

Live chimeras between two species of mouse,
Mus musculus
and
Mus caroli
, were produced by blastocyst injection. These chimeras were entirely similar to
M. musculus
↔
M. musculus
chimeras in their somatic tissue organization. This is the first report of completely normal development of interspecific chimeras in mammals.
Indoor Air Pollution, Tobacco Smoke, and Public Health
Authors: Repace James L. , Lowrey Alfred H.
Published: October 2006

An experimental and theoretical investigation is made into the range and nature of the exposure of the nonsmoking public to respirable suspended particulates from cigarette smoke. A model incorporating both physical and sociological parameters is shown to be useful in understanding particulate levels from cigarette smoke in indoor environments. Observed levels of particulates correlate with the predictions of the model. It is shown that nonsmokers are exposed to significant air pollution burdens from indoor smoking. An assessment of the public health policy implications of these burdens is presented.
Alteration in Connections Between Muscle and Anterior Horn Motoneurons After Peripheral Nerve Repair
Authors: Brushart Thomas M. , Mesulam M.-Marsel
Published: October 2006

The connections between the spinal cord and lower leg muscles of the rat are significantly altered by repair of the intervening sciatic nerve. Muscles supplied by the peroneal branch of the sciatic are innervated by fewer motoneurons after sciatic repair. Many of these neurons originally innervated the peroneal muscles, and others formerly served the antagonistic tibial muscles. Perikarya in the size range of alpha motoneurons regained peripheral connections with greater frequency than those in the gamma range. There are thus postoperative defects in the extent and specificity of alpha reinnervation as well as in the degree of gamma control.
Flavor-Illness Aversions: the Peculiar Roles of Odor and Taste in Memory for Poison
Authors: Palmerino Claire C. , Rusiniak Kenneth W. , Garcia John
Published: October 2006

When either taste or odor alone was followed by poison, rats acquired a strong aversion for the taste but not for odor, especially if poison was delayed. When odor-taste combinations were poisoned, however, odor aversions were potentiated, as if odor could gain the enduring memorial property of taste by associative contiguity.
Therapy of Spontaneous Metastases by Intravenous Injection of Liposomes Containing Lymphokines
Authors: Fidler Isaiah J.
Published: October 2006

Mice of two different strains were injected subcutaneously with spontaneously metastasizing syngeneic melanomas. After 4 to 6 weeks, the local tumors were removed and, 3 days after surgery, treatment of the metastases was initiated. The treatment consisted of intravenous injections of liposomes containing lymphokines or control supernatant fluids. Liposomes were injected twice weekly for 3 weeks, and the mice were killed 2 weeks later. Seventy-three percent of the mice injected with liposomes containing lymphokines were free of metastases, whereas only 10 percent of the mice treated with control liposomes were tumor-free. These experiments suggest that this form of therapy may provide a valuable addition to the more conventional approaches to the eradication of cancer metastases.
Swim Bladder Volume Maintenance Related to Initial Oceanic Migratory Depth in Silver-Phase
Anguilla rostrata
Authors: Kleckner Robert C.
Published: October 2006

Gas deposition rates in the swim bladders of postmetamorphic (silver)
Anguilla rostrata
eels are about five times greater than those of premetamorphic (yellow) individuals. This extends the maximum depth at which silver eels can maintain swim bladder volume and prepares them for their spawning migration to the Sargasso Sea.
Carboxyhemoglobin Levels in an Unstable Hemoglobin Disorder (Hb Zürich): Effect on Phenotypic Expression
Authors: Zinkham W. H. , Houtchens R. A. , Caughey W. S.
Published: October 2006

The affinity of Hb Zürich for carbon monoxide is approximately 65 times that of normal hemoglobin. The carboxyhemoglobin content in serum from individuals with Hb Zürich ranged from 3.9 to 6.7 percent in nine nonsmokers and from 9.8 to 19.7 percent in six smokers. Rates of hemolysis and hemoglobin denaturation were less in smokers than in nonsmokers, effects that may be secondary to the stabilization of Hb Zürich by carbon monoxide.
Cell Variants Showing Differential Susceptibility to Ultraviolet Light—Induced Transformation
Authors: Kakunaga Takeo , Crow Janet D.
Published: October 2006

Six variant clones isolated from a subclone of BALB/3T3-A31 clone were classified into three groups according to their different susceptibilities to cell transformation by ultraviolet light irradiation: highly susceptible, intermediately susceptible, and resistant. All variant clones showed similar susceptibility to cytotoxic effects induced by ultraviolet light.
Histone Gene Expression: Progeny of Isolated Early Blastomeres in Culture Make the Same Change as in the Embryo
Authors: Arceci Robert J. , Gross Paul R.
Published: October 2006

Stage-specific changes in histone synthesis during sea urchin development reflect the expression of different sets of genes. The three kinds of blastomeres formed at the 16-cell stage are the earliest "determined" cells and fall into three distinct size classes. At this stage the cells synthesize only "early" histones. Such blastomeres can survive and divide in culture after being separated from the embryo, whether or not they are permitted to aggregate. With or without reaggregation, cultured progeny cells of each type of isolated blastomere perform the same changeover of histone synthesis as takes place in the intact embryo, that is, they begin spontaneously to synthesize a new set, the "late" histone variants. Normal contact relations among cells of the embryo are, therefore, not required for this programmed change in gene expression.
Visually Induced Self-Motion Sensation Adapts Rapidly to Left-Right Visual Reversal
Authors: Oman Charles M. , Bock Otmar L. , Huang Jen-Kuang
Published: October 2006

After 1 to 3 hours of active movement while wearing vision-reversing goggles, 9 of 12 (stationary) human subjects viewing a moving stripe display experienced a self-rotation illusion in the same direction as seen stripe motion, rather than in the opposite (normal) direction. This result indicates that the neural pathways which process visual self-rotation cues can undergo rapid adaptive modification.
Liver Tumors Induced in Rats by Oral Administration of the Antihistaminic Methapyrilene Hydrochloride
Authors: Lijinsky W. , Reuber M. D. , Blackwell B.-N.
Published: October 2006

The antihistaminic over-the-counter drug methapyrilene hydrochloride, mixed with food at a concentration of 0.1 percent, was administered to 50 male and 50 female Fischer rats. A second group of 50 male and 50 female rats was given the same treatment together with 0.2 percent of sodium nitrite added to the food. Almost all of the rats in both groups developed liver neoplasms, mainly hepatocellular carcinomas and cholangiocarcinomas. The first rat died with a liver neoplasm at the 43rd week. Over 50 percent of the rats in both groups had metastases from the carcinomas of the liver to distant organs. Control rats treated with nitrite only, or untreated, did not develop liver neoplasms. There was no discernible effect of nitrite on the carcinogenicity of methapyrilene hydrochloride.
Endorphin-Mediated Increases in Pain Threshold During Pregnancy
Authors: Gintzler Alan R.
Published: October 2006

Maternal pain thresholds in rats were determined during various stages of pregnancy and parturition by measuring the intensity of electric shock that elicited reflexive jumping. There was a gradual rise in the pain threshold between 16 and 4 days prior to parturition and a more abrupt rise 1 to 2 days before that event. This increase was abolished by long-term administration of the narcotic antagonist naltrexone. The endorphin system is thus an important component of intrinsic mechanisms that modulate responsiveness to aversive stimuli. The data also demonstrate the activation during pregnancy of an endorphin system that is apparently quiescent in nonpregnant female rats treated the same way.
Rapid Effect of Triiodothyronine on the Mitochondrial Pathway in Rat Liver in Vivo
Authors: Sterling Kenneth , Brenner Milton A. , Sakurada Toshiro
Published: October 2006

Intravenous injections of minute doses of triiodothyronine were administered to thyroidectomized rats 30 minutes before they were killed. Hepatic mitochondria were isolated rapidly and formation of adenosine triphosphate and consumption of oxygen were assessed by a 2-minute incubation. Hormone injection enhanced formation of adenosine triphosphate 114 to 217 percent over control values, with a proportionate increase in consumption of oxygen. The ratio of phosphate to oxygen was about 2.0, signifying tightly coupled oxidative phosphorylation. Stimulation was not abolished by injection of cycloheximide, puromycin, actinomycin D, or chloramphenicol 1 hour before the rats were killed. This signifies direct mitochondrial stimulation by triiodothyronine in the absence of protein synthesis.
Human Monoclonal Antibody Against Forssman Antigen
Authors: Nowinski Robert , Berglund Cicely , Lane Judy , Lostrom Mark , Bernstein Irwin , Young William , Hakomori Sen-Itiroh , Hill Lucius , Cooney Marion
Published: October 2006

Hybrid cells formed between human lymphocytes and mouse myeloma cells produce human immunoglobulin in culture. Stable antibody-producing cell lines can be isolated after multiple cycles of low-density passage, cloning, and continued selection for immunoglobulin production. The origin and characteristics of a hybrid of human and mouse cells is described. This hybrid produces high concentrations (8.3 micrograms per milliliter) of human immunoglobulin M reactive with the terminal disaccharide of the Forssman glycolipid. These findings point to the potential use of human-mouse hybrid cells as a source of human monoclonal antibodies for therapeutic and diagnostic purposes.
Classical Conditioning: Induction of Luteinizing Hormone and Testosterone Secretion in Anticipation of Sexual Activity
Authors: Graham J. M. , Desjardins Claude
Published: October 2006

A classical conditioning paradigm was used to demonstrate that male rats can learn to secrete luteinizing hormone and testosterone in anticipation of sexual activity. Sexually naïve males were exposed to a neutral stimulus and then to a sexually receptive female once daily. After exposure to the paired stimuli for 14 trials, the neutral stimulus was as effective as the female in triggering luteinizing hormone and testosterone secretion. These findings provide two novel perspectives on the control of reproductive hormone secretion in male rats: (i) environmental cues, which males learn to associate with sexual activity, induce the secretion of hormones that regulate pituitary-testis function, and (ii) classical conditioning may be used as a noninvasive method to evoke functional alterations in the secretion of luteinizing hormone and presumably the neuroendocrine pathways that mediate its release.
Silent Nucleotide Substitutions and the Molecular Evolutionary Clock
Authors: Jukes Thomas H.
Published: October 2006

Half of the nucleotide substitutions during the evolutionary divergence of genes in animals, bacteria, and viruses are silent changes. These result from an inherent biochemical property of DNA and are fixed by genetic drift. Evolution may be viewed as a device for protecting DNA molecules from extinction.
Gyrate Atrophy of the Choroid and Retina: Improved Visual Function Following Reduction of Plasma Ornithine by Diet
Authors: Kaiser-Kupfer Muriel I. , de Monasterio Francisco M. , Valle David , Walser MacKensie , Brusilow Saul
Published: October 2006

In a patient with gyrate atrophy of the choroid and retina, an arginine-deficient diet has reduced plasma ornithine concentration fivefold during the past 20 months. Subjective improvement in her visual function was noted approximately 15 months after institution of the diet. This has been documented by improvements in the electroretinogram, dark-adaptation, and color vision. The improvement involves rod and, to a lesser extent, cone function. The results, although preliminary and limited to a single patient, suggest that reduction of plasma ornithine with a low arginine diet is beneficial in this disease.
Unmyelinated Axons in the Posterior Funiculi
Authors: Langford Lauren A. , Coggeshall Richard E.
Published: October 2006

Electron microscopy of the dorsal funiculus in the rat reveals that most axons in this pathway are unmyelinated. These axons have not previously been counted, nor are they considered in modern studies on the organization of the dorsal funiculus. Because of the importance of this pathway in somatic sensation, it is important to understand that these fibers exist and that they are present in greater numbers than the well-studied myelinated axons.
Arsenic Accumulation in Great Barrier Reef Invertebrates
Authors: Benson A. A. , Summons R. E.
Published: October 2006

Arsenic concentrates in the kidneys of the giant clams of Australia's Great Barrier Reef. The highest concentrations measured were 1004 parts per million, of which most, 2066 parts per million, were in the water-soluble fraction containing trimethylarsoniumlactate and its derivatives. This accumulation is ascribed to a mechanism in which oceanic arsenate is assimilated by symbiotic zooxanthellae and subsequently deposited in host tissues. The gills are the major site of arsenic excretion by these animals. Gill membrane arsenolipids mediate exposure of their trimethylarsonium groups to the sea and its biological oxidative activities.
Phenytoin-Induced Teratogenesis: A Mouse Model
Authors: Finnell R. H.
Published: October 2006

Malformations associated with the fetal hydantoin syndrome have been reproduced in a mouse model. The occurrence of these defects was correlated with maternal serum concentrations, but not with maternal or fetal genotype or the presence of a seizure disorder.
Cigarette Smoking in the 1970's: The Impact of the Antismoking Campaign on Consumption
Authors: Warner Kenneth E.
Published: October 2006

Per capita cigarette consumption has declined annually since 1973. This downturn represents a new nonsmoking ethos, which is also reflected in the legislative successes of the nonsmokers' rights movement. Time series regression analysis of cigarette demand suggests that, in the absence of the antismoking campaign, consumption would have exceeded its 1978 level by more than a third.
Exercise Hyperpnea and Locomotion: Parallel Activation from the Hypothalamus
Authors: Eldridge Frederic L. , Millhorn David E. , Waldrop Tony G.
Published: October 2006

Unanesthetized decorticate cats walked or ran normally on a treadmill either spontaneously or during electrical stimulation of the subthalamic "locomotor" region. The respiratory response usually preceded the locomotor response and increased in proportion to locomotor activity despite control or ablation of respiratory feedback mechanisms. Respiration increased similarly in paralyzed animals during fictive locomotion despite the absence of muscular contraction or movement. Hypothalamic command signals are thus primarily responsible for the proportional driving of locomotion and respiration during exercise.
Essential Hypertension: Central and Peripheral Norepinephrine
Authors: Lake C. R. , Gullner H. G. , Polinsky R. J. , Ebert M. H. , Ziegler M. G. , Bartter F. C.
Published: October 2006

The concentration of norepinephrine in cerebrospinal fluid from patients with essential hypertension is higher than that from healthy normal volunteers, but the concentrations of norepinephrine in plasma from these groups are similar. This finding indicates that central nervous system noradrenergic hyperactivity occurs in essential hypertension but apparently is not reflected in abnormal function of the peripheral sympathetic nervous system in these patients.
Spontaneous Hypertension Ion Cross-Suckled Rats
Authors: McMurtry John P. , Wright Gary L. , Wexler Bernard C.
Published: October 2006

Genetically normotensive Sprague-Dawley rats nursed by spontaneously hypertensive foster mothers develop sustained high blood pressure. Some factor related to the genetically programmed hypertension of the foster mother is probably transmitted to the infant rats through her milk. Alternatively, the hyperkinetic behavior of the mother may activate a hypertensinogen in young having the proper constellation of genes.
Unique Eye of Probable Evolutionary Significance
Authors: Eakin Richard M. , Brandenberger Jean L.
Published: October 2006

The eyes in the brain of a larval flatworm studied by electron microscopy are dissimilar. Light-sensitive structures in the right eye are microvilli; those in the left eye, the unique one, are both microvillar and ciliary. Perhaps this is evidence for the origin of a microvillar line of photoreceptoral evolution from a more primitive ciliary line.
Activation of Exocytosis by the Heterotrimeric G Protein G
i3
Authors: Aridor Meir , Rajmilevich Gladys , Beaven Michael A. , Sagi-Eisenberg Ronit
Published: October 2006

Secretagogues of rat peritoneal mast cells, such as mastoparan and compound 48/80, induce mast cell exocytosis by activating directly the guanosine triphosphate-binding proteins that are required for exocytosis. The introduction of a synthetic peptide that corresponds to the carboxyl-terminal end sequence of Gα
i3
into the cells specifically blocked this secretion. Similar results were obtained when antibodies to this peptide were introduced. The Gα
i3
was located in both the Golgi and the plasma membrane, but only the latter source of Gα
i3
appeared to be essential for secretion. These results indicate that Gα
i3
functions to control regulated exocytosis in mast cells.
Obesity Genes: Beneficial Effects in Heterozygous Mice
Authors: Coleman Douglas L.
Published: October 2006

The mouse mutant genes obese (
ob
) and diabetes (
db
) cause similar obesity-diabetes states in homozygotes. These obesity syndromes are characterized by a more efficient conversion of food to lipid and, once stored, a slower rate of catabolism on fasting. Heterozygous mice, either
ob
/+ or
db
/+, survived a prolonged fast significantly longer than normal homozygotes (+/+); this suggests that the heterozygotes exhibited increased metabolic efficiency, a feature normally associated with both homozygous mutants. The existence of this thriftiness trait, if manifested by heterozygous carriers in wild populations, would lend credence to the thrifty gene concept of diabetes. Beneficial effects of normally deleterious genes may have played a role in the development of diabetes-susceptible human populations, as well as having provided the survival advantage that has allowed both the development and successful establishment of species in desert and other less affluent regions.
Tyrosine Phosphorylation of Actin in
Dictyostelium
Associated with Cell-Shape Changes
Authors: Howard Peter K. , Sefton Bartholomew M. , Firtel Richard A.
Published: October 2006

When
Dictyostelium
cells that have initiated their developmental program upon starvation are returned to growth medium, there is a rapid and transient de novo tyrosine phosphorylation of a 43-kilodalton protein. This protein was found to be actin. Most of the phosphorylation occurred in a single, minor acidic isoform of actin. Developing cells that had been returned to growth medium lost their pseudopod extensions, became round, and had reduced adhesion to the substratum. These effects occurred with kinetics that matched the increase in tyrosine phosphorylation of actin. In mutant cell lines in which the gene for the phosphotyrosine phosphatase PTP1 had been disrupted, tyrosine phosphorylation of actin was rapid and more prolonged. These cells responded with proportionally accelerated kinetics of cell rounding. Cell lines overexpressing PTP1 had diminished amplitude and duration of actin tyrosine phosphorylation and exhibited diminished cell-shape change and an accelerated return to the extended cell-shape morphology seen in starved cells.
Presence of Mitochondrial large Ribosomal RNA Outside Mitochondria in Germ Plasm of
Drosophila melanogaster
Authors: Kobayashi Satoru , Amikura Reiko , Okada Masukichi
Published: October 2006

Mitochondrial large ribosomal RNA (mtlrRNA) has been identified as a cytoplasmic factor that induces pole cell formation in embryos whose ability to form a germ line has been abolished by treatment with ultraviolet light. In situ hybridization analyses reveal that mtlrRNA is enriched in germ plasm and is tightly associated with polar granules, the distinctive organelles of germ plasm, which supports the idea that mtlrRNA functions in pole cell formation. This suggests that a product from the mitochondrial genome, along with nuclear products, participates in a key event in embryonic development: determination of the germ line.
Increased Activity of L-Type Ca
2+
Channels Exposed to Serum from Patients with Type I Diabetes
Authors: Juntti-Berggren Lisa , Larsson Olof , Rorsman Patrik , Ämmälä Carina , Bokvist Krister , Wåhlander Karin , Nicotera Pierluigi , Dypbukt Jeanette , Orrenius Sten , Hallberg Anders , Berggren Per-Olof
Published: October 2006

Type I diabetes [insulin-dependent diabetes mellitus (IDDM)] is an autoimmune disease associated with the destruction of pancreatic β cells. Serum from patients with IDDM increased L-type calcium channel activity of insulin-producing cells and of GH
3
cells derived from a pituitary tumor. The subsequent increase in the concentration of free cytoplasmic Ca
2+
([Ca
2+
]
i
) was associated with DNA fragmentation typical of programmed cell death or apoptosis. These effects of the serum were prevented by adding a blocker of voltage-activated L-type Ca
2+
channels. When the serum was depleted of immunoglobulin M (IgM), it no longer affected [Ca
2+
]
i
. An IgM-mediated increase in Ca
2+
influx may thus be part of the autoimmune reaction associated with IDDM and contribute to the destruction of β cells in vivo.
MHC-Restricted Depletion of Human Myelin Basic Protein-Reactive T Cells by T Cell Vaccination
Authors: Zhang Jingwu , Medaer Robert , Stinissen Piet , Hafler David , Raus Jef
Published: October 2006

Activated autoreactive T cells are potentially pathogenic and regulated by clonotypic networks. Experimental autoimmune diseases can be treated by inoculation with autoreactive T cells (T cell vaccination). In the present study, patients with multiple sclerosis were inoculated with irradiated myelin basic protein (MBP)-reactive T cells. T cell responses to the inoculates were induced to deplete circulating MBP-reactive T cells in the recipients. Regulatory T cell lines isolated from the recipients inhibited T cells used for vaccination. The cytotoxicity of the CD8
+
T cell lines was restricted by major histocompatibility antigens. Thus, clonotypic interactions regulating autoreactive T cells in humans can be induced by T cell vaccination.
High-Resolution Conformation of Gramicidin A in a Lipid Bilayer by Solid-State NMR
Authors: Ketchem R. R. , Hu W. , Cross T. A.
Published: October 2006

Solid-state nuclear magnetic resonance spectroscopy of uniformly aligned preparations of gramicidin A in lipid bilayers has been used to elucidate a high-resolution dimeric structure of the cation channel conformation solely on the basis of the amino acid sequence and 144 orientational constraints. This initial structure defines the helical pitch as single-stranded, fixes the number of residues per turn at six to seven, specifies the helix sense as right-handed, and identifies the hydrogen bonds. Refinement of this initial structure yields reasonable hydrogen-bonding distances with only minimal changes in the torsion angles.
The Conserved Pre-mRNA Splicing Factor U2AF from
Drosophila
: Requirement for Viability
Authors: Kanaar Roland , Roche Siobhan E. , Beall Eileen L. , Green Michael R. , Rio Donald C.
Published: October 2006

The large subunit of the human pre-messenger RNA splicing factor U2 small nuclear ribonucleoprotein auxiliary factor (hU2AF
65
) is required for spliceosome assembly in vitro. A complementary DNA clone encoding the large subunit of
Drosophila
U2AF (dU2AF
50
) has been isolated. The dU2AF
50
protein is closely related to its mammalian counterpart and contains three carboxyl-terminal ribonucleoprotein consensus sequence RNA binding domains and an amino-terminal arginine- and serine-rich (R/S) domain. Recombinant dU2AF
50
protein complements mammalian splicing extracts depleted of U2AF activity. Germline transformation of
Drosophila
with the dU2AF
50
complementary DNA rescues a lethal mutation, establishing that the dU2AF
50
gene is essential for viability. R/S domains have been found in numerous metazoan splicing factors, but their function is unknown. The mutation in
Drosophila
U2AF will allow in vivo analysis of a conserved R/S domain-containing general splicing factor.
Long-Range Photoinduced Electron Transfer Through a DNA Helix
Authors: Murphy C. J. , Arkin M. R. , Jenkins Y. , Ghatlia N. D. , Bossmann S. H. , Turro N. J. , Barton J. K.
Published: October 2006

Rapid photoinduced electron transfer is demonstrated over a distance of greater than 40 angstroms between metallointercalators that are tethered to the 5′ termini of a 15-base pair DNA duplex. An oligomeric assembly was synthesized in which the donor is Ru(phen)
2
dppz
2+
(phen, phenanthroline, and dppz, dipyridophenazine) and the acceptor is Rh(phi)
2
phen
3+
(phi, phenanthrenequinone diimine). These metal complexes are intercalated either one or two base steps in from the helix termini. Although the ruthenium-modified oligonucleotide hybridized to an unmodified complement luminesces intensely, the ruthenium-modified oligomer hybridized to the rhodium-modified oligomer shows no detectable luminescence. Time-resolved studies point to a lower limit of 10
9
per second for the quenching rate. No quenching was observed upon metallation of two complementary octamers by Ru(phen)
3
2+
and Rh(phen)
3
3+
under conditions where the phen complexes do not intercalate. The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.
Modulation of Synaptic Transmitter Release by Repetitive Postsynaptic Action Potentials
Authors: Weight Forrest F. , Erulkar S. D.
Published: October 2006

The effect of repetitive action potentials in the postsynaptic axon on the release of synaptic transmitter from the presynaptic terminal was investigated at the squid giant synapse. Repetitive antidromic stimulation of the postsynaptic axon resulted in a reduction in the excitatory postsynaptic potential (EPSP). The reduction in transmitter release was accompanied by a decrease in the presynaptic spike after-hyperpolarization (AH). Increasing the concentration of extracellular potassium ions also reduced the EPSP and decreased the amplitude of the presynaptic spike AH. The reduction in transmitter release resulting from repetitive postsynaptic impulses is attributed to the accumulation of extracellular potassium ions. It is proposed that the accumulation of extracellular potassium ions resulting from repetitive postsynaptic activity may modulate synaptic transmission and function as an integrative mechanism in the nervous system.
Histologic Structures Preserved for 21,300 Years
Authors: Zimmerman Michael R. , Tedford Richard H.
Published: October 2006

Histologic examination of rehydrated tissue samples from late Pleistocene (Alaskan) mammal mummies demonstrates that the preservative effect of freezing and drying extends to remains 15,000 to 25,000 years old. Some muscle and liver tissue retained identifiable histologic structures. Most tissues were completely disintegrated and partly replaced by masses of bacteria, an indication of considerable postmortem decay before the remains were entombed beneath the permafrost zone.
Fetal Hemoglobin Restriction to a Few Erythrocytes (F Cells) in Normal Human Adults
Authors: Boyer Samuel H. , Belding Thomas K. , Margolet Louise , Noyes Andrea N.
Published: October 2006

During adult life, the quantity of fetal hemoglobin (HbF) present in F cells—that is, rare erythrocytes which are reactive with rabbit antiserum to human HbF during microscopic immunodiffusion—is sufficient to account for all of the small quantity (less than 0.7 percent) of HbF normally present in whole blood. Thus, erythrocytes are normally heterogeneous with respect to the presence of HbF.
High Levels of HIV-1 in Plasma During All Stages of Infection Determined By Competitive PCR
Authors: Piatak M. , Saag M. S. , Yang L. C. , Clark S. J. , Kappes J. C. , Luk K.-C. , Hahn B. H. , Shaw G. M. , Lifson J. D.
Published: October 2006

Quantitative competitive polymerase chain reaction (QC-PCR) methods were used to quantify virion-associated human immunodeficiency virus type-1 (HIV-1) RNA in plasma from 66 patients with Centers for Disease Control stage I to IVC1 infection. HIV-1 RNA, ranging from 100 to nearly 22,000,000 copies per milliliter of plasma (corresponding to 50 to 11,000,000 virions per milliliter), was readily quantified in all subjects, was significantly associated with disease stage and CD4
+
T cell counts, and decreased by as much as 235-fold with resolution of primary infection or institution of antiretroviral therapy. Plasma virus levels determined by QC-PCR correlated with, but exceeded by an average of 60,000-fold, virus titers measured by endpoint dilution culture. Quantitation of HIV-1 in plasma by QC-PCR may be useful in assessing the efficacy of antiretroviral agents, especially in early stage disease when conventional viral markers are often negative.
Nitric Oxide And Carbon Monoxide Produce Activity-Dependent Long-Term Synaptic Enhancement in Hippocampus
Authors: Zhuo Min , Small Scott A. , Kandel Eric R. , Hawkins Robert D.
Published: October 2006

Nitric oxide (NO) and carbon monoxide (CO) may act as retrograde messages for long-term potentiation (LTP) in the hippocampus. Zinc protoporphyrin IX, an inhibitor of the enzyme that produces CO, blocked induction of LTP in the CA1 region of hippocampal slices. Application of either NO or CO to slices produced a rapid and long-lasting increase in the size of evoked synaptic potentials if, and only if, the application occurred at the same time as weak tetanic stimulation. This long-term enhancement was spatially restricted to synapses from active presynaptic fibers and appeared to involve mechanisms utilized by LTP, occluding the subsequent induction of LTP by strong tetanic stimulation. The enhancement by NO and CO was not blocked by an
N
-methyl-D-aspartate (NMDA) receptor blocker, suggesting that NO and CO act downstream from the NMDA receptor. Also, CO produced long-term enhancement when paired with low-frequency stimulation. These results are consistent with the hypothesis that NO and CO, either alone or in combination, serve as retrograde messages that produce activity-dependent presynaptic enhancement during LTP.
Probing the Mechanism of Staphylococcal Nuclease with Unnatural Amino Acids: Kinetic and Structural Studies
Authors: Judice J. Kevin , Gamble Theresa R. , Murphy Elizabeth C. , de Vos Abraham M. , Schultz Abraham M.
Published: October 2006

Staphylococcal nuclease is an enzyme with enormous catalytic power, accelerating phosphodiester bond hydrolysis by a factor of 10
16
over the spontaneous rate. The mechanistic basis for this rate acceleration was investigated by substitution of the active site residues Glu
43
, Arg
35
, and Arg
87
with unnatural amino acid analogs. Two Glu
43
mutants, one containing the nitro analog of glutamate and the other containing homoglutamate, retained high catalytic activity at pH 9.9, but were less active than the wild-type enzyme at lower pH values. The x-ray crystal structure of the homoglutamate mutant revealed that the carboxylate side chain of this residue occupies a position and orientation similar to that of Glu
43
in the wild-type enzyme. The increase in steric bulk is accommodated by a backbone shift and altered torsion angles. The nitro and the homoglutamate mutants display similar pH versus rate profiles, which differ from that of the wild-type enzyme. Taken together, these studies suggest that Glu
43
may not act as a general base, as previously thought, but may play a more complex structural role during catalysis.
Potentiation by the β Subunit of the Ratio of the Ionic Current to the Charge Movement in the Cardiac Calcium Channel
Authors: Neely Alan , Wei Xiangyang , Olcese Riccardo , Birnbaumer Lutz , Stefani Enrico
Published: October 2006

The voltage-activated rabbit cardiac calcium channel α
1
subunit was expressed in
Xenopus
oocytes. The charge movement of its voltage sensor was measured and related to the opening of the ion-conducting pore. The half-activation potential for charge movement was 35 millivolts more negative than that for pore opening. Coexpression of the cardiac calcium channel β subunit reduced this difference without affecting charge movement. Thus, intramolecular coupling between the voltage sensor and the channel pore opening can be facilitated by a regulatory subunit.