bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotational Invariance in Visual Pattern Recognition by Pigeons and Humans
Authors: Hollard Valerie D. , Delius Juan D.
Published: October 2006

Pigeons and humans chose which one of two alternative visual forms was identical to, or a mirror image of, a previously presented sample form. The two comparison forms were presented in various orientations with respect to the sample. The two species yielded similar accuracies, but although human reaction times depended linearly on the angular disparities, those of the pigeon did not. Humans appeared to apply a well-known, thoughtlike, mental rotation procedure to the problem, whereas pigeons seemed to rely on a more efficient automatic process that humans can use only in simpler rotational invariance tasks. Mirror-image forms may be better discriminated by the pigeon's visual system than by the human one.
Ban of DDT and Subsequent Recovery of Reproduction in Bald Eagles
Authors: Grier James W.
Published: October 2006

Reproduction of bald eagles in northwestern Ontario declined from 1.26 young per breeding area in 1966 to a low of 0.46 in 1974 and then increased to 1.12 in 1981. Residues of DDE in addled eggs showed a significant inverse relation, confirming the effects of this toxicant on bald eagle reproduction at the population level and the effectiveness of the ban on DDT. The recovery from DDE contamination in bald eagles appears to be occurring much more rapidly than predicted.
Eye Movements of Preschool Children
Authors: Kowler Eileen , Martins Albert J.
Published: October 2006

Accurate recordings of eye movements of children 4 and 5 years old show that their eye movements differed from those of adults. During maintained fixation, saccades were large (1° to 2°) and smooth eye movement speeds were high (45 minutes of arc per second). Saccade latencies were highly variable during target step tracking. Smooth pursuit latencies were longer than those of adults. These hitherto unknown characteristics limit a child's ability to use eye movements to acquire visual information.
Impaired Brain Growth in Neonatal Rats Exposed to Ethanol
Authors: Diaz Jaime , Samson Herman H.
Published: October 2006

Infant rat pups, fed through intragastric cannulas from postnatal day 4 through day 18, showed a 19 percent reduction in total brain weight when ethanol was included in their diet on days 4 through 7. This reduction in brain weight occurred even though body growth in the experimental rats was equal to that of their littermate controls. The ethanol-exposed animals were markedly hypoactive during the period of drug administration, then displayed gross body tremors for 3 to 5 days. Throughout the study, the animals treated with ethanol had poor motor coordination and were hyperresponsive. These brain and behavioral effects appear similar to those seen in fetal alcohol syndrome.
Sustained Intracerebroventricular Infusion of Brain Fuels Reduces Body Weight and Food Intake in Rats
Authors: Davis John D. , Wirtshafter David , Asin Karen E. , Brief Deborah
Published: October 2006

Long-term infusion of glucose, β-hydroxybutyrate, and glycerol into the third ventricle of the rat brain caused a stabilization of body weight at a lower than normal level. Among the glucose- and glycerol-treated animals this weight loss was caused in part by temporary hypophagia. Among the animals treated with β-hydroxybutyrate the weight loss was unaccompanied by a reduction in food intake. The results are consistent with the view that the systems controlling food intake and body weight are sensitive to the availability of brain fuels. They are not consistent, however, with the view that these control systems monitor calories independently of their source.
Nematode Development After Removal of Egg Cytoplasm: Absence of Localized Unbound Determinants
Authors: Laufer John S. , von Ehrenstein Gunter
Published: October 2006

Embryos of
Caenorhabditis elegans
develop into fertile adults after cell fragments, containing presumptive cytoplasm of somatic and germ line precursors, are extruded from uncleaved eggs or early blastomeres through laser-induced holes in the eggshells. This suggests that the determinate development of this worm is not dependent on the prelocalization of determinants in specific regions of the egg cytoplasm.
Opiate Withdrawal in Utero Increases Neonatal Morbidity in the Rat
Authors: Lichtblau Leonard , Sparber Sheldon B.
Published: October 2006

Long-term oral administration of the long-acting opiate 1-α-acetylmethadol (LAAM) to female rats beginning on the day of conception interfered with the dams' ability to carry litters to term. When treatment was initiated 3 weeks prior to mating this effect was not observed. Daily administration of the opiate antagonist naloxone from day 14 of gestation through term, to precipitate withdrawal in utero, resulted in increased stillbirths, decreased pup weight and size, and weight loss 24 hours after birth. These data question the validity of animal experiments which purport to be models for methadone maintenance programs but in which treatment is started immediately prior to or soon after conception. They also suggest that withdrawal in utero may be responsible for many of the adverse effects of opiates on human and animal development.
Increased Intracranial Self-Stimulation in Rats After Long-Term Administration of Desipramine
Authors: Fibiger H. C. , Phillips A. G.
Published: October 2006

The effects of long- and short-term administration of the tricyclic antidepressant desipramine on intracranial self-stimulation in rats were studied with electrodes in the A10 region of the dopamine-containing cell bodies of the ventromedial tegmentum. Long-term desipramine administration resulted in a significant shift to the left in the ascending portion of the rate-current intensity function, indicating that the activity of the mesolimbic dopamine system was enhanced. These findings point to a possible dopaminergic mechanism of action of antidepressants and support speculations concerning the role of dopamine-containing neurons in the pathophysiology of depression.
Hibernation and Longevity in the Turkish Hamster
Mesocricetus brandti
Authors: Lyman Charles P. , O'Brien Regina C. , Greene G. Cliett , Papafrangos Elaine D.
Published: October 2006

A positive correlation was found between the length of life of 288 Turkish hamsters and the amount of time spent in hibernation, suggesting that the process of aging is slowed during hibernation.
Measles Virus Nucleotide Sequences: Detection by Hybridization in Situ
Authors: Haase A. T. , Ventura P. , Gibbs C. J. , Tourtellotte W. W.
Published: October 2006

A tritium-labeled probe that detects measles virus nucleotide sequences was hybridized in situ to cells infected with measles virus and to sections of brain tissue from patients with subacute sclerosing panencephalitis and from patients with multiple sclerosis. The measles virus genome was detected in many cells in subacute sclerosing panencephalitis where this virus would have been missed by methods such as immunofluorescence. Measles virus sequences were also found in two foci in one of four cases of multiple sclerosis. This refined method of hybridization in situ, which can be useful in the search for covert virus infections of man, provides evidence that viruses may be involved in multiple sclerosis.
Right-Handedness: A Consequence of Infant Supine Head-Orientation Preference?
Authors: Michel George F.
Published: October 2006

Most newborn infants (65 percent) preferred to lie with their heads turned to the right, whereas 15 percent showed a distinct preference for the left. Orientation preference is maintained for at least 2 months and predicts preferential hand use in reaching tasks at both 16 and 22 weeks. Right head-orientation preference in early infancy may contribute to the early development of right-handedness.
Cystinuria in the Maned Wolf of South America
Authors: Bovée K. C. , Bush M. , Dietz J. , Jezyk P. , Segal S.
Published: October 2006

Of 42 maned wolves in zoos or live-trapped in Brazil, 34 had excessive cystine in their urine. Renal clearance studies of five of the affected wolves revealed a variable defect for the reabsorption of cystine and dibasic amino acids. The renal tubular handling of other solutes including glucose, phosphate, sodium, potassium, and uric acid was considered normal. Urinary calculi composed of cystine were found in four wolves and proved fatal in three of them. With the exception of the high incidence in this species, this hereditary disease resembles the disorder described in dogs and humans.
Metastatic Potential Is Positively Correlated with Cell Surface Sialylation of Cultured Murine Tumor Cell Lines
Authors: Yogeeswaran G. , Salk P. L.
Published: October 2006

The ability of murine tumor cells to metastasize spontaneously from subcutaneous sites is positively correlated with the total sialic acid content of the cells in culture, the degree to which the sialic acid is exposed on the tumor cell surface, and, most strongly, with the degree of sialylation of galactosyl and
N
-acetylgalactosaminyl residues in cell surface glycoconjugates. These findings suggest that sialic acid on the cell surface may play a role in tumor cell metastasis.
Freeze-Fracture Cytochemistry: Replicas of Critical Point-Dried Cells and Tissues After Fracture-Label
Authors: Pinto da Silva Pedro , Kachar Bechara , Torrisi Maria Rosaria , Brown Charles , Parkison Clifford
Published: October 2006

Applications of the new fracture-labeling techniques for the observation of cytochemical labels on platinum-carbon replicas are described. Frozen cells, embedded in a cross-linked protein matrix, and frozen tissues are fractured with a scalpel under liquid nitrogen, thawed, labeled, dehydrated by the critical point drying method, and replicated. This method allows direct, high-resolution, two-dimensional chemical and immunological characterization of the cellular membranes in situ, as well as detection of sites within cross-fractured cytoplasm and extracellular matrix.
Single Neostriatal Efferent Axons in the Globus Pallidus: A Light and Electron Microscopic Study
Authors: Chang H. T. , Wilson C. J. , Kitai S. T.
Published: October 2006

Intracellularly labeled rat neostriatal projection neurons were analyzed with both light and electron microscopy. The axons of medium spiny neurons were traced into the globus pallidus and were found to make synaptic contacts with pallidal dendrites. Despite the common somato-dendritic morphology of the neostriatal projection neurons, two different distribution patterns of efferent axons were observed, indicating the presence of functionally different medium spiny neurons in the neostriatum.
Toxic Injury to Isolated Hepatocytes Is Not Dependent on Extracellular Calcium
Authors: Smith Martyn T. , Thor Hjördis , Orrenius Sten
Published: October 2006

Freshly isolated hepatocytes from phenobarbital-treated rats were incubated in the presence or absence of extracellular calcium with three differently acting liver cell toxins, namely carbon tetrachloride, bromobenzene, and ethylmethanesulfonate. In the absence of extracellular calcium these three compounds were far more toxic to the cells than in its presence. This result is inconsistent with the hypothesis that an influx of extracellular calcium is required as the final step in toxic liver cell injury.
Information Resources: Knowledge and Power in the 21st Century
Authors: Oettinger Anthony G.
Published: October 2006

Every society is an information society and every organization an information organization. Hence information is a basic resource like materials and energy. The need to ask "Who has a resource? Who wants it? How can you get it? and What are the terms of trade?" links any resource to political or economic power. For information resources, traditional answers are now inadequate owing to the growing abundance and versatility of the fruits of our unprecedented engineering mastery over the microscopic information processes embodied in devices such as large-scale integrated circuits and microcomputers. Illustrative of the evolution of new answers and of their import are the consequences of competition within and between the computer and telecommunications industries, of our reliance on satellites and other technical means for both the prevention and the conduct of war, of the growth of information occupations relative to other jobs, and of domestic and international struggles over freedom of information versus control over it.
Tandem Mass Spectrometry
Authors: McLafferty Fred W.
Published: October 2006

Coupling mass spectrometers in series provides a new technique that has many advantages for the analysis of specific organic compounds in complex mixtures. Sensitivity to picograms of targeted compounds can be achieved with high specificity and nearly instantaneous response. The targeted compound is selectively ionized, and its characteristic ions are separated from most others of the mixture in the first mass spectrometer. The selected primary ions are then decomposed by collision, and from the resulting products the final mass analyzer selects secondary ions characteristic of the targeted compound. Tandem mass spectrometry can achieve specificities and sensitivities equivalent to those of methods such as radioimmunoassay and gas chromatography/mass spectrometry, while performing analyses in much shorter times.
Gene Affecting Superoxide Dismutase Activity Linked to the Histocompatibility Complex in H-2 Congenic Mice
Authors: Novak R. , Bosze Z. , Matkovics B. , Fachet J.
Published: October 2006

The activity of cyanide-sensitive, Cu-Zn superoxide dismutase (SOD) was studied in liver cytosols from H-2 congenic strains of mice. Higher SOD activity was found in livers of mice having H-2
b
/A.BY, B10, and C
3
H.SW/haplotypes than in those of H-2
a
, H-2
k
and H-2
d
haplotypes. Segregation studies supported these correlations. In H-2 recombinant strains of mice, the genes influencing the liver SOD activity occur, as ascertained by mapping techniques, at or near the H-2D region of the major histocompatibility complex.
Reading Senseless Sentences: Brain Potentials Reflect Semantic Incongruity
Authors: Kutas Marta , Hillyard Steven A.
Published: October 2006

In a sentence reading task, words that occurred out of context were associated with specific types of event-related brain potentials. Words that were physically aberrant (larger than normal) elicited a late positive series of potentials, whereas semantically inappropriate words elicited a late negative wave (N400). The N400 wave may be an electrophysiological sign of the "reprocessing" of semantically anomalous information.
Asbestos-Induced Epithelial Changes in Organ Cultures of Hamster Trachea: Inhibition by Retinyl Methyl Ether
Authors: Mossman B. T. , Craighead J. E. , MacPherson B. V.
Published: October 2006

The epithelium of the hamster trachea in organ culture undergoes hyperplasia and squamous metaplasia after exposure to the amphibole types of asbestos, crocidolite and amosite. These changes are inhibited when the synthetic vitamin A analog, retinyl methyl ether, is incorporated into the culture medium. These findings suggest a possible use for retinoids in the prevention and treatment of respiratory tract disease associated with environmental exposure to asbestos.
Schizophrenia: Elevated Cerebrospinal Fluid Norepinephrine
Authors: Lake C. R. , Sternberg D. E. , van Kammen D. P. , Ballenger J. C. , Ziegler M. G. , Post R. M. , Kopin I. J. , Bunney W. E.
Published: October 2006

Concentrations of norepinephrine in cerebrospinal fluid are higher in schizophrenic patients, particularly in those with paranoid features, than in normal volunteer subjects of the same age. This observation supports recent reports of elevated concentrations of norepinephrine in specific brain areas adjacent to the cerebral ventricles of paranoid schizophrenic patients. Overflow of the amine from periventricular regions into the cerebrospinal fluid may reflect abnormally high release or diminished enzymatic destruction of norepinephrine in patients with schizophrenia.
Cigarette Smoking Associated with Sleep Difficulty
Authors: Soldatos Constantin R. , Kales Joyce D. , Scharf Martin B. , Bixler Edward O. , Kales Anthony
Published: October 2006

A group of 50 smokers experienced greater sleep difficulty than a group of 50 nonsmokers matched by age and sex. The two groups did not differ in personality patterns or drug consumption. Also, sleep patterns significantly improved in a group of eight chronic smokers when they abstained from cigarette smoking. These findings are consistent with reports on the stimulant effects of nicotine.
Access of Urinary Nonvolatiles to the Mammalian Vomeronasal Organ
Authors: Wysocki Charles J. , Wellington Judith L. , Beauchamp Gary K.
Published: October 2006

Guinea pigs were allowed to investigate urine that contained rhodamine, a nonvolatile fluorescent dye. Guinea pigs given free access to dyed urine exhibited fluorescence in their vomeronasal and septal organs but not on their olfactory epithelium. Fluorescence was not seen when unadulterated urine was presented. Thus compounds of low volatility, which do not reach the olfactory epithelium, may stimulate the vomeronasal system and provide information that is normally not provided by gustation or olfaction.
Adapting to Two Orientations: Disinhibition in a Visual Aftereffect
Authors: Magnussen Svein , Kurtenbach Wolfgang
Published: October 2006

The tilt aftereffect of adapting to two different orientations simultaneously is weaker than the aftereffect of adapting to the more effective of the two orientations alone. This finding is consistent with explanations of orientational aftereffects in terms of lateral inhibition between cortical orientation detectors, but not with explanations in terms of neural "fatigue" from excitation.
Vomeronasal Pump: Significance for Male Hamster Sexual Behavior
Authors: Meredith Michael , Marques David M. , O'Connell Robert J. , Stern F. Lee
Published: October 2006

Vomeronasal chemoreceptors segregated within the vomeronasal organ are important for male hamster sexual behavior. An autonomically controlled vascular pump, previously demonstrated in anesthetized animals, can transport stimuli to the receptors. Interruption of the efferent nerves controlling the pump results in behavioral deficits similar to those produced by interruption of the afferent nerves carrying information from the vomeronasal organ to the brain. Pump activation is thus a prerequisite for normal vomeronasal stimulation in behaving animals.
Role of Nitrogen Dioxide in the Biosynthesis of Nitrosamines in Mice
Authors: Iqbal Zafar M. , Dahl Kristine , Epstein Samuel S.
Published: October 2006

Groups of three to four mice were gavaged with aqueous solutions of 2 milligrams of morpholine, after which they were exposed to nitrogen dioxide in inhalation chambers at concentrations of 0.2 to 50 parts per million for up to 4 hours. At sequential intervals during the exposure, mice were frozen and pulverized in liquid nitrogen, and the mice powder was extracted with ice-cold 35 percent aqueous methanol and dichloromethane; organic-phase concentrates were analyzed for
N
-nitrosomorpholine with a thermal energy analyzer interfaced to a gas chromatograph. The
N
-nitrosomorpholine yields, ranging up to about 2.3 micrograms per mouse, were time-dependent relative to the duration of exposure to nitrogen dioxide and dose-dependent relative to the concentrations of nitrogen dioxide; control levels (in mice that were gavaged with morpholine or distilled water and then exposed to air instead of nitrogen dioxide) were less than 5 nanograms per mouse. These preliminary studies demonstrate the in vivo nitrosating potential of nitrogen oxides.
Visual Aftereffects Derived from Inspection of Orthogonally Moving Patterns
Authors: Riggs Lorrin A. , Day Ross H.
Published: October 2006

Alternate inspection of patterns moving in orthogonal directions induces an aftereffect in which a stationary test pattern seems to move in a new direction. This direction is the resultant of the two directions of aftereffect that would have arisen from separately inspecting each of the moving patterns. The direction in which objects appear to move, like their color and depth, can thus depend on a synthesis of unperceived components.
Reactivation of Infant Memory
Authors: Rovee-Collier Carolyn K. , Sullivan Margaret W. , Enright Mary , Lucas Debora , Fagen Jeffrey W.
Published: October 2006

Three-month-old infants learned to activate a crib mobile by means of operant footkicks. Retention of the conditioned response was assessed during a cued recall test with the nonmoving mobile. Although forgetting is typically complete after an 8-day retention interval, infants who received a reactivation treatment—a brief exposure to the reinforcer 24 hours before retention testing—showed no forgetting after retention intervals of either 2 or 4 weeks. Further, the forgetting function after a reactivation treatment did not differ from the original forgetting function. These experiments demonstrate that (i) "reactivation" or "reinstatement" is an effective mechanism by which early experiences can continue to influence behavior over lengthy intervals and (ii) memory deficits in young infants are best viewed as retrieval deficits.
Critical-Path Scheduling of Mental Processes in a Dual Task
Authors: Schweickert Richard
Published: October 2006

Scheduling theory is used to extend the additive factors method of analyzing reaction times to tasks involving concurrent processing. Data indicate that mental processes in a double-stimulation experiment by Becker are executed in a critical-path network. A relationship predicted for the timing of the responses of the task is shown to hold.
Human Taste: Response and Taste Bud Number in Fungiform Papillae
Authors: Arvidson Kristina , Friberg Ulf
Published: October 2006

The number of basic taste qualities registered by single human fungiform papillae is correlated with the number of taste buds borne on these papillae. Multiple sensitivity was demonstrated both in single fungiform papillae and in single taste buds, with response to all four of the basic taste qualities occurring in a single taste bud.
Biological and Sociocultural Effects on Handedness: Comparison Between Biological and Adoptive Families
Authors: Carter-Saltzman Louise
Published: October 2006

Data from adoption studies on handedness indicate that the effects of shared biological heritage are more powerful determinants of hand preference than sociocultural factors. Biological offspring were found to show nonrandom distributions of right- and non-right-handedness as a function of parental handedness; these distributions were consistent with the results of previous family studies. In contrast, the handedness distribution of adopted children as a function of parental handedness was essentially random.
Monkey Responses to Three Different Alarm Calls: Evidence of Predator Classification and Semantic Communication
Authors: Seyfarth Robert M. , Cheney Dorothy L. , Marler Peter
Published: October 2006

Vervet monkeys give different alarm calls to different predators. Recordings of the alarms played back when predators were absent caused the monkeys to run into trees for leopard alarms, look up for eagle alarms, and look down for snake alarms. Adults call primarily to leopards, martial eagles, and pythons, but infants give leopard alarms to various mammals, eagle alarms to many birds, and snake alarms to various snakelike objects. Predator classification improves with age and experience.
Anesthetics as tEratogens: Nitrous Oxide Is Fetotoxic, Xenon Is Not
Authors: Lane Geoffrey A. , Nahrwold Michael L. , Tait Alan R. , Taylor-Busch Margaret , Cohen Peter J. , Beaudoin Allan R.
Published: October 2006

Exposure of pregnant rats to the anesthetic nitrous oxide on the ninth day of gestation causes fetal resorption, skeletal anomalies, and macroscopic lesions including encephalocele, anophthalmia, microphthalmia, and gastroschisis. The inert gas xenon, which has anesthetic properties similar to those of nitrous oxide, does not cause teratogenic effects under the same experimental conditions.
Pineal Melatonin Rhythm: Reduction in Aging Syrian Hamsters
Authors: Reiter Russel J. , Richardson Bruce A. , Johnson Linda Y. , Ferguson Bonnie N. , Dinh Diep T.
Published: October 2006

The melatonin content measured by radioimmunoassay of the pineal gland over a 24-hour period (a light:dark cycle of 14 hours of light and 10 of darkness) was compared in young and old female and male Syrian hamsters. The young animals of both sexes exhibited roughly an eightfold rise in pineal melatonin during the dark phase of the cycle, whereas in the old hamsters the nocturnal rise in melatonin was almost completely absent. The results indicate a marked drop in pineal biosynthetic activity in the aging hamster.
A Metric for Thought: A Comparison of P300 Latency and Reaction Time
Authors: McCarthy Gregory , Donchin Emanuel
Published: October 2006

We confirm that the latency of the P300 component of the human event-related potential is determined by processes involved in stimulus evaluation and categorization and is relatively independent of response selection and execution. Stimulus discriminability and stimulus-response compatibility were manipulated independently in an "additive-factors" design. Choice reaction time and P300 latency were obtained simultaneously for each trial. Although reaction time was affected by both discriminability and stimulus-response compatibility, P300 latency was affected only by stimulus discriminability.
Giant Synaptic Potential Hypothesis for Epileptiform Activity
Authors: Johnston Daniel , Brown Thomas H.
Published: October 2006

According to one hypothesis, the paroxysmal depolarizing shift observed in the penicillin model of epilepsy results from a giant excitatory postsynaptic potential. This hypothesis has recently been questioned, primarily because it has never been subjected to rigorous experimental examination. Four quantitative predictions were derived from this hypothesis and tested in CA3 pyramidal neurons of the hippocampus. The four critical predictions concern the behavior of the paroxysmal depolarizing shift under current- and voltage-clamp conditions as a function of membrane potential. The experiments confirmed all four predictions.
Real-Time Color Graphics in Studies of Molecular Interactions
Authors: Langridge Robert , Ferrin Thomas E. , Kuntz Irwin D. , Connolly Michael L.
Published: October 2006

Studies of the structures and interactions of large biological molecules require both coordinate data and three-dimensional visualization. Orthodox molecular models often bear a tenuous relationship to the coordinate data. In contrast, computer graphics requires that the display directly and accurately represent the data, and storage of modified configurations and recovery of original structures are simple. Software has been developed that allows real-time display of color line and surface displays of several interacting molecules, while quantitatively monitoring the stereochemistry.
Membrane Conductance and Action Potential of a Regenerating Axonal Tip
Authors: Meiri Hamutal , Spira Micha E. , Parnas Itzak
Published: October 2006

The electrical membrane properties of axotomized and regenerating giant axons from the nerve cord of the cockroach
Periplaneta americana
were studied. Immediately after axotomy there was a decrease in resting potential, input resistance, and action potential amplitude near the cut end. This decrease was followed by the disappearance of the sodium-dependent action potential; an increase in the resting membrane conductance to K
+
, Na
+
, and Ca
2+
; and the appearance of a calcium-dependent action potential.
Ascending Endorphin Inhibition of Distress Vocalization
Authors: Herman Barbara H. , Panksepp Jaak
Published: October 2006

Distress vocalizations were produced in adult guinea pigs by electrical stimulation of the dorsomedial thalamus or the septum-preoptic area. Both of these forebrain-derived vocalizations were increased by systemic administration of naloxone and were inhibited by analgesic periventricular gray stimulation. Naloxone blocked the inhibitory effects of the analgesic stimulation on thalamic vocalizations. Stimulation of nonanalgesic mesencephalic sites in close proximity to the periventricular gray increased the anterior-elicited vocalizations. These data provide evidence for ascending endorphin-mediated inhibition of excitatory forebrain sites for distress vocalizations.
Fluorocarbons Reduce Myocardial Ischemic Damage After Coronary Occlusion
Authors: Glogar Dietmar H. , Kloner Robert A. , Muller James , DeBoer Laurence W. V. , Braunwald Eugene , Clark Leland C.
Published: October 2006

Open-chest, anesthetized dogs with occlusions of the left anterior descending coronary artery breathed 100 percent oxygen while they were bled to a hematocrit of 25 percent and infused with an approximately equal volume (40 milliliters per kilogram) of fluorocarbon preparation or Ringer solution. Dogs breathing room air and receiving no treatment served as controls. After undergoing 6 hours of coronary occlusion, animals bled and treated with fluorocarbons developed smaller infarctions than those receiving Ringer solution or no treatment.
Echolocation and Pursuit of Prey by Bats
Authors: Simmons James A. , Fenton M. Brock , O'Farrell Michael J.
Published: October 2006

Echolocating bats use different information-gathering strategies for hunting prey in open, uncluttered environments, in relatively open environments with some obstacles, and in densely cluttered environments. These situations differ in the extent to which individual targets such as flying insects can be detected as isolated objects or must be separated perceptually from backgrounds. Echolocating bats also differ in whether they use high-resolution, multidimensional images of targets or concentrate specifically on one particular target dimension, such as movement, to detect prey.
Ethanol Ingestion: Differences in Blood Acetaldehyde Concentrations in Relatives of Alcoholics and Controls
Authors: Schuckit Marc A. , Rayses Vidamantas
Published: October 2006

Blood acetaldehyde concentrations were significantly elevated after a moderate ethanol dose in 20 healthy young men with alcoholic parents or siblings compared to matched controls with no familial alcoholism.
Target Range-Sensitive Neurons in the Auditory Cortex of the Mustache Bat
Authors: O'Neill William E. , Suga Nobuo
Published: October 2006

Echolocating bats determine distance to targets by the time delay between their emitted biosonar pulses and the returning echoes. By varying the delay between synthetic pulses and echoes in stimulus pairs at various repetition rates and durations, neurons have been found in the auditory cortex of the mustache bat (
Pteronotus parnellii rubiginosus
) which are sensitive to target range during the search, approach, and terminal phases of prey capture or landing. Two classes of range-sensitive neurons were found: (i) tracking neurons, whose best delay for response to an echo following the emitted pulse becomes shorter and narrower as the bat closes in on the target, and (ii) range-tuned neurons, whose best delay is constant, and which respond to the target only when it is within a certain narrow fixed range. Range-tuned neurons are specialized for processing echoes only during a particular period of the search, approach, or terminal phases of echolocation, and they provide support for a theory of ranging in bats that incorporates groups of neurons with a spectrum of preferred echo delays to detect target distance.
Vomeronasal and Olfactory System Modulation of Maternal Behavior in the Rat
Authors: Fleming Alison , Vaccarino Franco , Tambosso Loretta , Chee Phyllis
Published: October 2006

The onset of maternal responsiveness by virgin female rats to foster pups was observed after (i) complete vomeronasal nerve cuts, (ii) partial olfactory bulb cuts, or (iii) the combined procedures. Although both vomeronasal nerve cuts and olfactory bulb cuts resulted in a more rapid onset of maternal care, relative to control animals with sham operations, animals sustaining the loss of both sources of olfactory input exhibited the shortest response latency. These findings are discussed in terms of the probable distinct functions of the two olfactory systems in the control of maternal behavior in the rat.
Fever and Reduced Iron: Their Interaction as a Host Defense Response to Bacterial Infection
Authors: Kluger Matthew J. , Rothenburg Barbara A.
Published: October 2006

When rabbits are infected with
Pasteurella multocida
, the concentration of iron in their plasma decreases and their rectal temperature rises. To determine whether the rise in body temperature (fever) and the fall in plasma iron may be a coordinated host defense response,
Pasteurella multocida
were grown in vitro at various temperatures and iron concentrations. At afebrile temperatures the bacteria grew equally well at low or high concentrations of iron. However, when the temperature of the bath was raised to a febrile temperature the growth of the bacteria was inhibited by the low, but not the high, iron concentrations. These data support the hypothesis that one of the mechanisms behind the adaptive (or beneficial) role of fever is the reduced ability of pathogenic bacteria to grow well at elevated temperatures in an iron-poor medium.
Present Status and Future Prospects for HIV Therapies
Authors: Johnston Margaret I. , Hoth Daniel F.
Published: October 2006

Since the discovery of human immunodeficiency virus (HIV) in 1983, significant progress has been made toward the discovery, development, and licensing of anti-HIV drugs. In vitro screens against whole virus are now being complemented by screens against specific viral targets, resulting in the development of clinical candidates acting at several critical stages of the viral life cycle. Despite these advances, clinical therapy remains largely palliative. In addition, it has recently been recognized that HIV resistance to most drugs may pose even greater obstacles. Moreover, emerging data on immunopathogenesis raise the possibility that even if virus was eliminated from an infected individual, the patient's immune system might not be capable of restoration to normal function. In the face of such obstacles, deeper insights into the pathogenic mechanisms of disease, aggressive exploitation of those mechanisms for therapeutic gain, and continued commitment of both public and private sectors to support and collaborate in this research are needed.
FMR1
Protein: Conserved RNP Family Domains and Selective RNA Binding
Authors: Ashley Claude T. , Wilkinson Keith D. , Reines Daniel , Warren Stephen T.
Published: October 2006

Fragile X syndrome is the result of transcriptional suppression of the gene
FMR1
as a result of a trinucleotide repeat expansion mutation. The normal function of the
FMR1
protein (FMRP) and the mechanism by which its absence leads to mental retardation are unknown. Ribonucleoprotein particle (RNP) domains were identified within FMRP, and RNA was shown to bind in stoichiometric ratios, which suggests that there are two RNA binding sites per FMRP molecule. FMRP was able to bind to its own message with high affinity (dissociation constant = 5.7 nM) and interacted with approximately 4 percent of human fetal brain messages. The absence of the normal interaction of FMRP with a subset of RNA molecules might result in the pleiotropic phenotype associated with fragile X syndrome.
Identification of an Alternative CTLA-4 Ligand Costimulatory for T Cell Activation
Authors: Hathcock Karen S. , Laszlo Gloria , Dickler Howard B. , Bradshaw Jeff , Linsley Peter , Hodes Richard J.
Published: October 2006

Stimulation of T cell proliferation generally requires two signals: The first signal is provided by the T cell receptor binding to antigen, and the second signal or costimulus is provided by a different receptor-ligand interaction. In mouse and human, the CD28-B7 interaction has been identified as a source of costimulatory signals. We have identified a cell surface molecule (GL1) that is distinct from B7 and abundantly expressed on activated B cells. On activated B cells GL1, rather than B7, is the predominant ligand for the T cell-activation molecule CTLA-4. GL1 provides a critical signal for T cell-dependent responses in vitro and in vivo.
Nonuniform Probability of Glutamate Release at a Hippocampal Synapse
Authors: Rosenmund Christian , Clements John D. , Westbrook Gary L.
Published: October 2006

A change in the probability of neurotransmitter release (
P
r
) is an important mechanism underlying synaptic plasticity. Although
P
r
is often assumed to be the same for all terminals at a single synapse, this assumption is difficult to reconcile with the nonuniform size and structure of synaptic terminals in the central nervous system. Release probability was measured at excitatory synapses on cultured hippocampal neurons by analysis of the progressive block of
N
-methyl-D-aspartate receptor-mediated synaptic currents by the irreversible open channel blocker MK-801. Release probability was nonuniform (range of 0.09 to 0.54) for terminals arising from a single axon, the majority of which had a low
P
r
. However, terminals with high
P
r
are more likely to be affected by the activity-dependent modulation that occurs in long-term potentiation.
Map-Based Cloning of a Protein Kinase Gene Conferring Disease Resistance in Tomato
Authors: Martin Gregory B. , Brommonschenkel Sergio H. , Chunwongse Julapark , Frary Anne , Ganal Martin W. , Spivey Rody , Wu Tiyun , Earle Elizabeth D. , Tanksley Steven D.
Published: October 2006

The
Pto
gene in tomato confers resistance to races of
Pseudomonas syringae
pv.
tomato
that carry the avirulence gene
avrPto
. A yeast artificial chromosome clone that spans the
Pto
region was identified and used to probe a leaf complementary DNA (cDNA) library. A cDNA clone was isolated that represents a gene family, at least six members of which genetically cosegregate with
Pto
. When susceptible tomato plants were transformed with a cDNA from this family, they were resistant to the pathogen. Analysis of the amino acid sequence revealed similarity to serine-threonine protein kinases, suggesting a role for
Pto
in a signal transduction pathway.
A MAP Kinase Targeted by Endotoxin and Hyperosmolarity in Mammalian Cells
Authors: Han J. , Lee J.-D. , Bibbs L. , Ulevitch R. J.
Published: October 2006

Mammalian cells respond to endotoxic lipopolysaccharide (LPS) by activation of protein kinase cascades that lead to new gene expression. A protein kinase, p38, that was tyrosine phosphorylated in response to LPS, was cloned. The p38 enzyme and the product of the
Saccharomyces cerevisiae
HOG1
gene, which are both members of the mitogen-activated protein (MAP) kinase family, have sequences at and adjacent to critical phosphorylation sites that distinguish these proteins from most other MAP kinase family members. Both HOG1 and p38 are tyrosine phosphorylated after extracellular changes in osmolarity. These findings link a signaling pathway in mammalian cells with a pathway in yeast that is responsive to physiological stress.
Absence of Pyruvate Decarboxylase Activity in Man: A Cause of Congenital Lactic Acidosis
Authors: Farrell Donald F. , Clark Arthur F. , Scott C. Ronald , Wennberg Richard P.
Published: October 2006

A complete deficiency in the pyruvate dehydrogenase system activity contributed to the death of a 6-month-old infant with congenital lactic acidosis. The enzymatic block could be isolated to the first component, pyruvate decarboxylase (E
1
) of the pyruvate dehydrogenase complex. This enzymatic deficiency allowed a demonstration of an "intercomplex" exchange of the components of the mammalian pyruvate dehydrogenase system and indicated that the first component is normally present in an apparent excess.
Chemotaxis Away from Uncouplers of Oxidative Phosphorylation in
Bacillus subtilis
Authors: Ordal George W. , Goldman Daniel J.
Published: October 2006

In a capillary assay, uncouplers of oxidative phosphorylation and inhibitors of electron transport are repellents for
Bacillus subtilis
. They also cause transient tumbling in naturally smooth swimming strains. Tumbling strains can be made to swim smoothly by addition of attractant and then immediately returned to tumbling by subsequent addition of repellent. Arsenate does not cause transient tumbling, suggesting that decrease in concentration of adenosine triphosphate does not cause tumbling and that adenosine triphosphate concentration does not govern tumbling frequency. Instead, the evidence suggests that diminution of the energized state of the membrane, or membrane potential, causes tumbling although the level of the energized state itself does not govern tumbling frequency.
Unidirectional Coupling of Gap Junctions Between Neuroglia
Authors: Robinson Stephen R. , Hampson Edith C. G. M. , Munro Mark N. , Vaney David I.
Published: October 2006

Gap junctions permit the passage of ions and small molecules between cells, thereby providing a basis for direct intercellular communication. In the rabbit retina, the low molecular weight dyes Lucifer yellow and biocytin passed readily from astrocytes into adjacent astrocytes, oligodendrocytes, and Müller cells. However, the dyes rarely passed from either oligodendrocytes or Müller cells into astrocytes. Unidirectional passage of dye suggests the presence of an asymmetric barrier to the movement of molecules through heterologous gap junctions and indicates the potential for a hierarchy of command between interconnected cells.
Direct Association of Adenosine Deaminase with a T Cell Activation Antigen, CD26
Authors: Kameoka Junichi , Tanaka Toshiaki , Nojima Yoshihisa , Schlossman Stuart F. , Morimoto Chikao
Published: October 2006

CD26, the T cell activation molecule dipeptidyl peptidase IV (DPPIV), associates with a 43-kilodalton protein. Amino acid sequence analysis and immunoprecipitation studies demonstrated that this 43-kilodalton protein was adenosine deaminase (ADA). ADA was coexpressed with CD26 on the Jurkat T cell lines, and an in vitro binding assay showed that the binding was through the extracellular domain of CD26. ADA deficiency causes severe combined immunodeficiency disease (SCID) in humans. Thus, ADA and CD26 (DPPIV) interact on the T cell surface, and this interaction may provide a clue to the pathophysiology of SCID caused by ADA deficiency.
HLA-DPB1 Glutamate 69: a Genetic Marker of Beryllium Disease
Authors: Richeldi Luca , Sorrentino Rosa , Saltini Cesare
Published: October 2006

Chronic beryllium disease (CBD) is a lung disorder related to beryllium exposure and is characterized by the accumulation in the lung of beryllium-specific CD4
+
major histocompatibility complex (MHC) class II-restricted T lymphocytes. Evaluation of MHC class II genes in 33 CBD cases and 44 controls has shown a negative association with HLA-DPB1
*
0401 (
P
< 0.001) and a positive association with HLA-DPB1
*
0201 (
P
< 0.05) alleles, which differ at residues 36, 55 to 56, and 69 of the β
1
chain. Among CBD cases, 97 percent expressed the HLA-DPB1
*
0201-associated glutamic acid (unaffected population, 30 percent;
P
< 0.001) at residue 69, a position involved in susceptibility to autoimmune disorders. This suggests that HLA-D
P
has a role in conferring susceptibility and that residue 69 of HLA-DPB1 could be used in risk assessment for CBD.
Neisseria gonorrhoeae
and
Neisseria meningitidis
: Extracellular Enzyme Cleaves Human Immunoglobulin A
Authors: Plaut Andrew G. , Gilbert Joanne V. , Artenstein Malcolm S. , Capra J. Donald
Published: October 2006

The gonococcus and meningococcus, which infect human mucosal surfaces, elaborate a highly specific proteolytic enzyme which cleaves the immunoglobulin A1 subclass of the principal mucosal antibody, immunoglobulin A (IgA). The susceptible Pro-Thr bond lies in a unique region of the IgA heavy chain; the IgA2 subclass, lacking this peptide bond, is enzyme resistant.
Long-Term Synaptic Facilitation in the Absence of Short-Term Facilitation in
Aplysia
Neurons
Authors: Emptage Nigel J. , Carew Thomas J.
Published: October 2006

Serotonin (5-HT) induces both short-term and long-term facilitation of the identified synaptic connections between sensory and motor neurons of
Aplysia
. Three independent experimental approaches showed that long-term facilitation can normally be expressed in the absence of short-term facilitation: (i) The 5-HT antagonist cyproheptadine blocked the induction of short-term but not long-term facilitation; (ii) concentrations of 5-HT below threshold for the induction of short-term facilitation nonetheless induced long-term facilitation; and (iii) localized application of 5-HT to the sensory neuron cell body and proximal synapses induced long-term facilitation in distal synapses that were not exposed to 5-HT and had not expressed short-term facilitation. These results suggest that short-term and long-term synaptic facilitation are induced in parallel in the sensory neurons and that the short-term process, because it is induced and expressed at the synapse, can occur locally, but the long-term process, because of its dependence on a nuclear signal, is expressed throughout the neuron.
Calcium Sparks: Elementary Events Underlying Excitation-Contraction Coupling in Heart Muscle
Authors: Cheng H. , Lederer W. J. , Cannell M. B.
Published: October 2006

Spontaneous local increases in the concentration of intracellular calcium, called "calcium sparks," were detected in quiescent rat heart cells with a laser scanning confocal microscope and the fluorescent calcium indicator fluo-3. Estimates of calcium flux associated with the sparks suggest that calcium sparks result from spontaneous openings of single sarcoplasmic reticulum (SR) calcium-release channels, a finding supported by ryanodine-dependent changes of spark kinetics. At resting intracellular calcium concentrations, these SR calcium-release channels had a low rate of opening (∼0.0001 per second). An increase in the calcium content of the SR, however, was associated with a fourfold increase in opening rate and resulted in some sparks triggering propagating waves of increased intracellular calcium concentration. The calcium spark is the consequence of elementary events underlying excitation-contraction coupling and provides an explanation for both spontaneous and triggered changes in the intracellular calcium concentration in the mammalian heart.
Detection of Transient Protein Folding Populations by Mass Spectrometry
Authors: Miranker Andrew , Robinson Carol V. , Radford Sheena E. , Aplin Robin T. , Dobson Christopher M.
Published: October 2006

Hydrogen-deuterium exchange measurements are becoming increasingly important in studies of the dynamics of protein molecules and, particularly, of their folding behavior. Electrospray ionization mass spectrometry (ESI-MS) has been used to obtain the distribution of masses within a population of protein molecules that had undergone hydrogen exchange in solution. This information is complementary to that from nuclear magnetic resonance spectroscopy (NMR) experiments, which measure the average occupancy of individual sites over the distribution of protein molecules. In experiments with hen lysozyme, a combination of ESI-MS and NMR was used to distinguish between alternative mechanisms of hydrogen exchange, providing insight into the nature and populations of transient folding intermediates. These results have helped to detail the pathways available to a protein during refolding.
Release of Active Cytokinin by a β-Glucosidase Localized to the Maize Root Meristem
Authors: Brzobohatý Břetislav , Moore Ian , Kristoffersen Peter , Bako Laszlo , Campos Narciso , Schell Jeff , Palme Klaus
Published: October 2006

A β-glucoside encoded by a cloned
Zea mays
complementary DNA (
Zm-p60.1
) cleaved the biologically inactive hormone conjugates cytokinin-O-glucosides and kinetin-N3-glucoside, releasing active cytokinin. Tobacco protoplasts that transiently expressed
Zm-p60.1
could use the inactive cytokinin glucosides to initiate cell division. The ability of protoplasts to sustain growth in response to cytokinin glucosides persisted indefinitely after the likely disappearance of the expression vector. In the roots of maize seedlings, Zm-p60.1 was localized to the meristematic cells and may function in vivo to supply the developing maize embryo with active cytokinin.