bluuebunny/crossref_metadata_2025 huggingface dataset:
Tumor Metastasis Is Not Due to Adaptation of Cells to a New Organ Environment
Authors: Nicolson Garth L. , Custead Susan E.
Published: October 2006

Murine B16 melanoma cells were adapted for lung survival and growth by allowing them to attach to Bio-Carrier beads and injecting the beads intravenously into normal mice. The beads lodged mechanically in the microcirculation of the lung. When the melanoma cells had grown into visible tumors from the arrested beads, the tumors were removed and the cells were dispersed, cultured to remove normal cells, and reattached to new beads. The process was repeated nine times. Previously another B16 subline was injected intravenously as a suspension of separate tumor cells. Those cells that survived and colonized the lungs were harvested, cultured, and injected again. This selection process was also repeated nine times. Only the subline that was injected in suspension was more metastatic than the parental line, indicating that metastasis involves selection of preexistent metastatic cells and is not an adaptive process by which all cells gradually acquire the ability to grow at particular organ sites.
Polyamines Inhibit the Protein Kinase 380—Catalyzed Phosphorylation of Eukaryotic Initiation Factor 2α
Authors: Kuroda Yoshikazu , Merrick William C. , Sharma Rameshwar K.
Published: October 2006

Polyamines putrescine, spermidine, and spermine specifically inhibit the PK 380—catalyzed phosphorylation of eukaryotic initiation factor 2α (eIF-2α). Since the PK 380—dependent phosphorylation of eIF-2α inhibits the initiation or protein synthesis, the possibility exists that the polyamines enhance protein synthesis by inhibiting the phosphorylation of eIF-2α by PK 380.
Behaviorally Conditioned Immunosuppression and Murine Systemic Lupus Erythematosus
Authors: Ader Robert , Cohen Nicholas
Published: October 2006

Development of autoimmune disease in female New Zealand hybrid mice was dramatically modified by classical conditioning of immunosuppression. Groups of animals received each week a solution of sodium saccharin (conditioned stimulus). One group of conditioned animals received an injection of cyclophosphamide (the unconditioned stimulus) after half of the weekly occasions when they received the saccharin solution. The rate of development of proteinuria and mortality were significantly retarded in these conditioned mice relative to untreated controls and nonconditioned animals that received unpaired treatment with saccharin and cyclophosphamide.
X-ray Induction of Persistent Hypersensitivity to Mutation
Authors: Frank Joseph P. , Williams Jerry R.
Published: October 2006

The progeny of x-irradiated V79 cells are hypersensitive to PUVA-(8-methoxypsoralen plus longwave ultraviolet light) induced mutation at the locus for hypoxanthine-guanine phosphoribosyl transferase. This hypersensitivity is most evident at low doses of PUVA that do not induce mutation in non-x-irradiated cells. The hypersensitivity is evoked by x-irradiation delivered as a single dose or as multiple fractions over a long period and persists for at least 108 days of exponential growth. This radiation-induced hypersensitivity to subsequent mutation is a new phenomenon that may be relevant to multistage carcinogenesis.
Impulse-Coded and Analog Signaling in Single Mechanoreceptor Neurons
Authors: Pasztor Valerie M. , Bush Brian M. H.
Published: October 2006

Although most sensory neurons convey temporally coded impulses to the central nervous system, certain nonspiking receptors use only graded afferent signals. Each of three large nerve fibers from the lobster oval organ, a mechanoreceptor subserving ventilation, carry both impulses and graded potentials. Thus, both impulse frequency and receptor potential amplitude are available for information transfer.
Selective, Naloxone-Reversible Morphine Depression of Learned Behavioral and Hippocampal Responses
Authors: Mauk Michael D. , Warren John T. , Thompson Richard F.
Published: October 2006

Morphine administered intravenously causes immediate and complete abolition of a simple learned response (classically conditioned nictitating membrane extension in rabbit) and of the associated learning-induced increase in hippocampal neuron activity. Both effects are completely reversed by low doses of naloxone. Morphine has no effect at all on behavioral performance of the unconditioned reflex response.
Food Science And Nutrition: The Gulf Between Rich and Poor
Authors: Hulse Joseph H.
Published: October 2006

The people of economically developed countries benefit greatly from modern food science. They are protected from food contamination, have access to a great variety of food, and need spend little time preparing it. The poor in developing countries enjoy few of the benefits of food science. Their diets are often nutritionally deficient and they spend many hours each day processing their food and searching for wood with which to cook it. In most tropical countries food losses between harvest or slaughter and eventual consumption are inestimable. Efforts to improve post-harvest food systems in developing countries require the attention and ingenuity of many scientific disciplines and the support of all development agencies.
Antidepressants Alter Cerebrovascular Permeability and Metabolic Rate in Primates
Authors: Preskorn Sheldon H. , Raichle Marcus E. , Hartman Boyd K.
Published: October 2006

External detection of the annihilation radiation produced by water labeled with oxygen-15 was used to measure cerebrovascular permeability and cerebral blood flow in six rhesus monkeys. Use of oxygen-15 also permitted assessment of cerebral metabolic rate in two of the monkeys. Amitriptyline produced a dose-dependent, reversible increase in permeability at plasma drug concentrations which are therapeutic for depressed patients. At the same concentrations the drug also produced a 20 to 30 percent reduction in cerebral metabolic rate. At higher doses normal autoregulation of cerebral blood flow was suspended, but responsivity to arterial carbon dioxide was normal.
Dietary Calcium in Human Hypertension
Authors: McCarron David A. , Morris Cynthia D. , Cole Clarice
Published: October 2006

A pilot survey was made of the dietary calcium intake of normotensive and hypertensive individuals. Compared to 44 normotensive controls, 46 subjects with essential hypertension reported significantly less daily calcium ingestion (668 ± 55 milligrams compared to 886 ± 89 milligrams). The intake of other nutrients, including sodium and potassium, was very similar in the two groups. The hypertensives differed from the controls primarily in their consumption of nonfluid dairy products. The data suggest that inadequate calcium intake may be a previously unrecognized factor in the development of hypertension.
Sex and Handedness Differences in Cerebral Blood Flow During Rest and Cognitive Activity
Authors: Gur Ruben C. , Gur Raquel E. , Obrist Walter D. , Hungerbuhler Jean Pierre , Younkin Donald , Rosen Anna D. , Skolnick Brett E. , Reivich Martin
Published: October 2006

Cognitive activity resulted in increased flow of blood to the cerebral hemispheres. The increase was greater to the left hemisphere for a verbal task and greater to the right hemisphere for a spatial task. The direction and degree of hemispheric flow asymmetry were influenced by sex and handedness, females having a higher rate of blood flow per unit weight of brain, and females and left-handers having a greater percentage of fast-clearing tissue, presumably gray matter.
Fruit and Vegetable Pigments as Indicators
Authors: Pratt O. B. , Swartout H. O.
Published: October 2006

(1) Solutions of many fruit pigments act as indicators.

(2) These solutions are easily prepared and stable, and the pH range of their color changes is in most cases conveniently near the neutral point.

(3) As liquid indicators they can be used in titrating acids, but not bases.

(4) Their greatest usefulness depends upon the fact that very satisfactory test papers can be made with them in a simple and inexpensive way.
Events in the Evolution of Pre-Proinsulin
Authors: Douthart Richard J. , Norris Franklin H.
Published: October 2006

An extensive computer-assisted analysis of known pre-proinsulin coding sequences has shown correlations that can be interpreted as evidence for an intron-mediated juxtaposition of exons in the evolution of these genes. The evidence includes the discovery that the regions of the pre-proinsulin genes that code for the signal peptide consist of nearly tandem repeating units of nine base pairs. This pattern reappears in the C region of the genes after a large intron that occurs in three of the four genes analyzed. A model is proposed in which primordial insulin was coded for by two separate minigenes arising from a gene duplication, each with identical or nearly identical signal peptide coding regions. The minigenes fused into one transcriptional unit mediated by the large intron, and the signal peptide coding region of one of the putative minigenes evolved into the latter portion of the C peptide coding region.
Deoxyglucose Analysis of Retinotopic Organization in Primate Striate Cortex
Authors: Tootell Roger B. H. , Silverman Martin S. , Switkes Eugene , De Valois Russell L.
Published: October 2006

We have anatomically analyzed retinotopic organization using the
14
C-labeled 2-deoxy-D-glucose method. The method has several advantages over conventional electrophysiological mapping techniques. In the striate cortex, the anatomical substrate for retinotopic organization is surprisingly well ordered, and there seems to be a systematic relationship between ocular dominance strips and cortical magnification. The 2-deoxyglucose maps in this area appear to be largely uninfluenced by known differences in long-term metabolic activity. This method should prove useful in analyzing retinotopic organization in various visual areas of the brain and in different species.
Fish Vision and the Detection of Planktonic Prey
Authors: Hairston Nelson G. , Li Kao T. , Easter Stephen S.
Published: October 2006

Planktivorous sunfish of various sizes were studied to ascertain whether growth-related changes in the retina are related to the ability to capture small planktonic crustaceans. Behaviorally, the larger fish detected and captured crustaceans that subtended smaller visual angles. Histological examination of the retinas revealed that the distance between cones, measured in minutes of visual angle, decreased as the animals grew, suggesting that the larger retinas could resolve smaller objects. These correlated behavioral and anatomical results suggest that improved visual resolution contributes to improved predation. This finding provides a selective advantage for the continuous retinal growth noted in many fish.
Rapid Changes in Brain Benzodiazepine Receptors After Experimental Seizures
Authors: Paul Steven M. , Skolnick Phil
Published: October 2006

Seizures induced in the rat by electroshock or by injections of pentylenetetrazol increase the specific binding of diazepam to putative receptor sites in cerebral cortical membranes. The enhancement of diazepam binding results from a rapid increase in the number of available binding sites rather than a change in receptor affinity. The postictal increase in cortical benzodiazepine receptors suggests that the cerebral cortex might be more sensitive to the anticonvulsant effects of the benzodiazepines after seizures. This observation may be related to the mechanism of action of these drugs in the treatment of recurrent seizures such as status epilepticus.
Olfactory Sensitivity in Humans: Genetic Versus Environmental Control
Authors: Hubert Helen B. , Fabsitz Richard R. , Feinleib Manning , Brown Kenneth S.
Published: October 2006

Olfactory sensitivity to acetic acid, isobutyric acid, and 2-
sec
-butyl-cyclohexanone was tested in 97 adult male twin pairs to determine the extent to which variation in odor perception was genetically determined. Analysis of the data revealed no evidence for heritability of olfactory sensitivity. However, factors significantly associated with odor perception included cigar, pipe, and cigarette smoking; body fatness; alcohol consumption; and diabetes mellitus.
Phencyclidine, Lysergic Acid Diethylamide, and Mescaline: Cerebral Artery Spasms and Hallucinogenic Activity
Authors: Altura Bella T. , Altura Burton M.
Published: October 2006

Phencyclidine (PCP), lysergic acid diethylamide (LSD), and mescaline produced potent contractile responses on isolated basilar and middle cerebral arteries, where, in terms of potency, LSD > mescaline > PCP. All three drugs produced cerebrovasospasm in a concentration range which parallels that needed for their psychotomimetic and intoxicating actions. Specific receptors for PCP, which subserve contraction and differ from those for LSD and mescaline, are found in cerebral arteries. Concentrations of PCP that produced near-maximum contractile responses on cerebral arteries were similar to those in the blood and brain of human subjects who had died from PCP overdoses. A specific calcium antagonist, verapamil, readily prevented (and reversed) PCP-induced vasospasm. This study provides direct evidence for PCP receptors in cerebral blood vessels, the biologic action of which can be reversed by a calcium antagonist; the clinical use of the latter could prove invaluable in treating PCP-intoxicated victims.
Dual Nature of Physiography
Authors: Glock Waldo S.
Published: October 2006

Physiography may be viewed from two distinct angles, the one dynamic, the other passive. The processes hold the fascination inherent in energy and force; the products exhibit all the beauty and diversity of form in the composition of landscapes. The tacit adoption of a particular view-point not only will avoid confusion but will also simplify to a great extent both oral and written presentation of physiographic subjects, especially to beginners. We ought, perhaps, to discriminate clearly between process and product.

In a restricted fashion geodynamics studies the process, force or activity, simply acknowledging the form as a passive result. Geomorphology considers that form to be a detailed expression of the influence of rock and structure and acknowledges the process as a cause chiefly in relation to the gross lineaments of the ensemble.

In a large fashion geodynamics is intimately associated with certain branches of geology, as sedimentation, while geomorphology connects physiography with geography. The dynamic interlude representing the active phase of physiography weaves the basic threads of geologic history.
Intracellular Oxidation-Reduction State Measured in Situ by a Multichannel Fiber-Optic Surface Fluorometer
Authors: Mayevsky Avraham , Chance Britton
Published: October 2006

The principles of the measurement in vivo of the oxidation-reduction state of intramitochrondrial pyridine nucleotides were used in establishing a multichannel fluorometer-reflectometer. This approach made possible the study of changes of mitochrondrial redox states in four different organs (brain, liver, kidney, and testis) of the same animal, as well as the monitoring of four different cortical areas of the same brain hemisphere. In the measurement of reduced nicotinamide adenine dinucleotide fluorescence, oximetric and movement artifacts are negligible, but blood volume changes and tissue absorption properties are a source of error. The corrected fluorescence is obtained by subtracting the reflectance from the fluorescence signal in 1:1 ratio. During graded hypoxia, the corrected fluorescence showed a gradual increase and was maximal during anoxia in all four organs tested.
Effects of Prenatal Sex Hormones on Gender-Related Behavior
Authors: Ehrhardt Anke A. , Meyer-Bahlburg Heino F. L.
Published: October 2006

Gender identity depends largely on postnatal environmental influences, while sex-dimorphic behavior and temperamental sex differences appear to be modified by prenatal sex hormones. A role of the prenatal endocrine milieu in the development of erotic partner preference, as in hetero-, homo-, or bisexual orientation, or of cognitive sex differences has not been conclusively demonstrated.
Sex Differences in the Effects of Unilateral Brain Damage on Intelligence
Authors: Inglis James , Lawson J. S.
Published: October 2006

A sexual dimorphism in the functional asymmetry of the damaged human brain is reflected in a test-specific laterality effect in male but not in female patients. This sex difference explains some contradictions concerning the effects of unilateral brain damage on intelligence in studies in which the influence of sex was overlooked.
Speech Perception Without Traditional Speech Cues
Authors: Remez Robert E. , Rubin Philip E. , Pisoni David B. , Carrell Thomas D.
Published: October 2006

A three-tone sinusoidal replica of a naturally produced utterance was identified by listeners, despite the readily apparent unnatural speech quality of the signal. The time-varying properties of these highly artificial acoustic signals are apparently sufficient to support perception of the linguistic message in the absence of traditional acoustic cues for phonetic segments.
Modular Segregation of Functional Cell Classes Within the Postcentral Somatosensory Cortex of Monkeys
Authors: Sur Mriganka , Wall John T. , Kaas Jon H.
Published: October 2006

The distribution of two functionally distinct cell types, presumably related to slowly and rapidly adapting mechanoreceptors in the skin, was explored within the representation of the glabrous hand in area 3b of the somatosensory cortex of monkeys. The two cell classes lie in relatively segregated alternating anteroposterior bands within the middle layers of the cortex.
Photoregulated Ion Binding
Authors: Blank M. , Soo L. M. , Wassermann N. H. , Erlanger B. F.
Published: October 2006

A photoregulated chelating agent has been synthesized. It is a photochromic azobenzene compound containing two iminodiacetic acid groups and can exist as
cis
and
trans
stereoisomers. The planar
trans
isomer does not bind zinc ions. On exposure to light of 320 nanometers, the
trans
isomer is converted to a nonplanar
cis
isomer, which, because of cooperativity between the two iminodiacetic acid groups, binds zinc ions with the value of the binding constant estimated to be 1.1 × 10
5
± 0.2 × 10
5
liters per mole at a ratio of one molecule of chelating agent to one zinc ion. The interconversion of the
cis
and
trans
isomers is reversible, suggesting possible application of this class of compounds as photoresponsive ion pumps.
The Hagfish Slime Gland: A Model System for Studying the Biology of Mucus
Authors: Downing Stephen W. , Salo Wilmar L. , Spitzer Robert H. , Koch Elizabeth A.
Published: October 2006

The hagfish slime gland may provide a model system for studying certain aspects of the biology of mucus. Mucus is obtained in nonhydrated form by electrically stimulating the anesthetized hagfish and the secretions are stirred into ammonium sulfate. Centrifugation and filtration are then used to isolate the two major secretory products, mucous vesicles and threads. Specific advantages of the model and potential applications for research are discussed.
Computer Averaging of Electron Micrographs of 40
S
Ribosomal Subunits
Authors: Frank Joachim , Verschoor Adriana , Boublik Miloslav
Published: October 2006

An enhanced lateral view of the 40
S
ribosomal subunit of HeLa cells has been obtained by computer averaging of single particles visualized in the electron microscope. Application of crystallographic criteria to independent averages shows that the reproducibility of the result is comparable to that obtained for thin, stained protein crystals by conventional Fourier filtration methods.
Tetrachlorodibenzo-
p
-Dioxin Quantitation in Stack-Collected Coal Fly Ash
Authors: Kimble B. J. , Gross M. L.
Published: October 2006

Gas chromatography-high resolution mass spectrometry has been used to quantitate tetrachlorodibenzo-
p
-dioxin (TCDD) in fly ash collected from the stack of a typical commercial coal-fired power plant. No TCDD was detected in this fly ash, but minute traces may be present below the detection limit of 1.2 parts per trillion (by weight). This finding indicates that this type of fossil-fueled power plant is not a large source of this compound in environmental samples, in contrast to the conclusions presented in a recent industrial report.
Prenatal Exposure to Diazepam Alters Behavioral Development in Rats
Authors: Kellogg Carol , Tervo Donna , Ison James , Parisi Thomas , Miller Richard K.
Published: October 2006

Characteristic potentiation of rat locomotion responses and acoustic startle reflexes that normally appear in the third postnatal week was absent in rats exposed to diazepam during the third week of gestation. Loss of these behaviors suggests a long-term effect that may result from changes in cellular development. Tissue undergoing neuronal differentiation may be especially sensitive to drugs that act on the central nervous system, and the period in which differentiation occurs is perhaps critical for the induction of changes that are later expressed as altered behavior.
Stereopsis in Human Infants
Authors: Fox Robert , Aslin Richard N. , Shea Sandra L. , Dumais Susan T.
Published: October 2006

Stereoscopic depth perception was tested in human infants by a new method based on attracting the infant's attention through movement of a stereoscopic contour formed from a dynamic random-element stereogram. The results reveal that stereopsis emerges at 3½ to 6 months of age, an outcome consistent with evidence for rapid postnatal development of the visual system.
Differences in the Distribution of Gray and White Matter in Human Cerebral Hemispheres
Authors: Gur Ruben C. , Packer Ira K. , Hungerbuhler Jean Pierre , Reivich Martin , Obrist Walter D. , Amarnek Wayne S. , Sackeim Harold A.
Published: October 2006

The distribution of gray matter in the two cerebral hemispheres was determined by the xenon-133 inhalation method. There was more gray matter relative to white matter in the left hemisphere than in the right, particularly in the frontal and precentral regions. This finding suggests that the organization of the left hemisphere, relative to that of the right, emphasizes processing or transfer within regions, or both, rather than transfer across regions.
Opiates and Opioid Peptides Hyperpolarize Locus Coeruleus Neurons in Vitro
Authors: Pepper Christine M. , Henderson Graeme
Published: October 2006

Intracellular recordings were made from locus coeruleus neurons in a brain slice preparation. Opiates and opioid peptides produced a dose-dependent, stereospecific, naloxone-reversible hyperpolarization of the neuronal membrane. This was associated with an increase in membrane conductance.
Testosterone-Mediated Sexual Dimorphism of Mitochondria and Lysosomes in Mouse Kidney Proximal Tubules
Authors: Koenig Harold , Goldstone Alfred , Blume Gary , Lu Chung Y.
Published: October 2006

In kidney proximal tubules of male mice the mitochondria are larger and more electron-lucent, autophagic vacuoles and lysosomes (predominantly myeloid bodies) more numerous and voluminous, and exocytosed intraluminal myeloid bodies more common than in females. Males also have higher kidney activities of mitochondrial cytochrome c oxidase and lysosomal hydrolases, and excrete larger quantities of hydrolases and protein in the urine. Orchiectomy evokes the feminine pattern whereas testosterone administration induces the male pattern. Endogenous testosterone modulates mitochondrial structure and function and enhances the activity of the lysosomal-vacuolar system in proximal tubule cells.
Mouse globin system: a functional and evolutionary analysis
Authors: Leder Philip , Hansen J. Norman , Konkel David , Leder Aya , Nishioka Yutaka , Talkington Carol
Published: October 2006

Structural and functional analysis of the mouse α-globin and β-globin genes reveals that the globin genes are encoded in discontinuous bits of coding information and that each gene locus is much more complex than was originally supposed. Each seems to consist of an array of several authentic genes as well as several apparently inactive pseudogenes. Comparison of the sequences of some of these genes to one another indicates that chromosomal DNA is a dynamic structure. Flanking and intervening sequences change in two ways: quickly, by duplication and extensive insertions and deletions, and slowly, by point mutation. Active coding sequences are usually limited to the slower mode of evolution. In addition to identifying fast and slow modes of evolution, it has also been possible to test the function of several signals that surround these genes and to identify those that appear to play a role in gene expression.
Elimination of Synapses in the Developing Nervous System
Authors: Purves Dale , Lichtman Jeff W.
Published: October 2006

Reduction of the number of axons that contact target cells may be a general feature of neural development. This process may underlie the progressively restricted malleability of the maturing nervous system.
Endoscopy: Developments in Optical Instrumentation
Authors: Epstein Max
Published: October 2006

Optical fibers transmit high-intensity illumination for viewing internal organs and tissue. Remote viewing is obtained by relays of lenses or graded-index-of-refraction rods in rigid endoscopes and by precisely aligned fiber-optic bundles in flexible fiberscopes. Endoscopy is considered for routine examinations, such as in colonoscopy. Lasers are used as surgical tools through endoscopes for cutting and coagulation. They may also be used to provide illumination for the efficient transmission of light through thin optical fibers.
Endogenous Potentials Generated in the Human Hippocampal Formation and Amygdala by Infrequent Events
Authors: Halgren Eric , Squires Nancy K. , Wilson Charles L. , Rohrbaugh John W. , Babb Thomas L. , Crandall Paul H.
Published: October 2006

Infrequent, attended, auditory and visual stimuli evoke large potentials in the human limbic system in tasks that usually evoke endogenous potentials at the scalp. The limbic potentials reverse polarity over small distances and correlate with unit discharges recorded by the same electrodes, indicating that they are locally generated.
Epileptiform Burst Afterhyperpolarization: Calcium-Dependent Potassium Potential in Hippocampal CA1 Pyramidal Cells
Authors: Alger B. E. , Nicoll R. A.
Published: October 2006

Synaptic excitation of hippocampal cells during blockade of synaptic inhibition results in an epileptiform "burst" potential followed by a prolonged afterhyperpolarization. This afterhyperpolarization resembles the one that is seen after the epileptic interictal spike and that is considered of critical importance in preventing seizure development. The afterhyperpolarization produced in the presence of γ-aminobutyric acid antagonists is associated with a conductance increase and is inhibitory. It can occur in an all-or-none fashion after a burst, is independent of chloride, and is depressed by barium. The afterhyperpolarization has a reversal potential of -86 millivolts, and the reversal potential is strongly dependent on the extracellular concentration of potassium. The afterhyperpolarization appears to be an intrinsic, inhibitory potassium potential mediated by calcium. This finding has implications for understanding the cellular mechanisms of epilepsy.
Phosphorus Distribution in the Nucleosome
Authors: Bazett-Jones D. P. , Ottensmeyer F. P.
Published: October 2006

The spatial distribution of phosphorus within active fraction nucleosomes reveals that the path of the DNA is consistent with one and three-fourths turns of DNA supercoiled around the outside of the protein core. This phosphorus distribution, obtained with an imaging electron spectrometer in a conventional transmission electron microscope, simultaneously establishes new limits of sensitivity for elemental microanalysis.
Body Weight and Composition in Laboratory Rats: Effects of Diets with High or Low Protein Concentrations
Authors: Donald Patillo , Pitts Grover C. , Pohl Stephen L.
Published: October 2006

Adult rats fed high concentrations of dietary protein for 9 weeks gained more weight than rats fed isoenergetic diets containing less protein. There were no significant differences in tail and body lengths among several groups of rats on diets containing different amounts of protein; however, total body fat was significantly greater in the rats fed on diets containing 25 percent protein compared to the rats fed 5 percent protein diets. These findings suggest that the role of dietary protein in obesity and other conditions deserves further scrutiny.
Direct Demonstration and Quantitation of the First Complement Component in Human Serum
Authors: Ziccardi R. J. , Cooper N. R.
Published: October 2006

The first component of complement, C1, can be demonstrated and quantitated in normal and pathological human serums by simple immunochemical techniques. All of the C1q, C1r, and C1s detected in normal serum was found to be in the C1 complex. A simple modification of these methods permitted the quantitation of free C1s in the presence of macromolecular C1, a technique which may prove useful in screening pathological serums.
Carbon Monoxide Automobile Emissions Measured from the Interior of a Traveling Automobile
Authors: Chaney Lucian W.
Published: October 2006

During a procedure to monitor carbon monoxide (CO) concentrations inside a traveling car, it was discovered that CO emissions from individual passing vehicles produced accurately measurable increases in the CO concentration. The CO produced by individual vehicles varied by three orders of magnitude; this finding demonstrates that a relatively small number of cars can be responsible for a high percentage of total vehicle CO emissions.
Plasticity: The Mirror of Experience
Authors: Spinelli D. Nico , Jensen Frances E.
Published: October 2006

A simple avoidance training procedure during early development produces massive neural traces in visual and somatic cortices of kittens reared in a normal environment. A preponderance of cells in these areas had response preferences for the stimuli used during training. Furthermore, some of these cells exhibited properties never found in normal animals not receiving such training. It appears that, even in an environment in which many other stimuli are present, some early experiences powerfully affect brain development and the way in which other experiences exert their effect.
Psychophysical Evidence for a Monocular Visual Cortex in Stereoblind Humans
Authors: Blake Randolph , Cormack Robert H.
Published: October 2006

Human observers who lack stereopsis reliably make eye-of-origin discriminations for grating patterns under conditions that render the performance of normal observers unreliable. This lends support to the view that stereoblind individuals possess proportions of monocular and binocular cortical cells similar to those of cats and monkeys deprived of early binocular visual experience.
HLA-A11 Epitope Loss Isolates of Epstein-Barr Virus From a Highly A11
+
Population
Authors: de Campos-Lima Pedro-Otavio , Gavioli Riccardo , Zhang Qian-Jin , Wallace Lesley E. , Dolcetti Riccardo , Rowe Martin , Rickinson Alan B. , Masucci Maria G.
Published: October 2006

Cytotoxic T lymphocytes (CTLs) control viral infections by recognizing viral peptides presented by major histocompatibility complex (MHC) class I molecules. Human leukocyte antigen (HLA)-A11-restricted CTLs that recognize peptide residues 416 to 424 of the Epstein-Barr virus (EBV) nuclear antigen-4 frequently dominate EBV-induced responses in A11
+
Caucasian donors. This epitope is conserved in type A EBV strains from Caucasians and central African populations, where A11 is relatively infrequent. However, strains from highly A11
+
populations in New Guinea carry a lysine-to-threonine mutation at residue 424 that abrogates CTL recognition and binding of the peptide to nascent A11 molecules. The results suggest that evolution of a widespread and genetically stable virus such as EBV is influenced by pressure from MHC-restricted CTL responses.
Restoration of HIV-Specific Cell-Mediated Immune Responses by Interleukin-12 in Vitro
Authors: Clerici Mario , Lucey Daniel R. , Berzofsky Jay A. , Pinto Ligia A. , Wynn Thomas A. , Blatt Stephen P. , Dolan Matthew J. , Hendrix Craig W. , Wolf Stanley F. , Shearer Gene M.
Published: October 2006

Peripheral blood mononuclear cells (PBMCs) from many asymptomatic individuals infected with human immunodeficiency virus-type 1 (HIV) are unresponsive as measured by in vitro T cell proliferation and interleukin-2 (IL-2) production to influenza virus and synthetic peptides of HIV envelope (Env). Strong influenza virus- and Env-stimulated IL-2 responses and T cell proliferation were restored when cultures were stimulated in the presence of IL-12. Interferon-γ production by PBMCs from HIV seropositive (HIV
+
) patients was also restored with IL-12. Furthermore, in vitro antigen-specific production of IL-2 and proliferation of PBMCs from HIV
-
donors were suppressed by antibody to IL-12, but were not enhanced by addition of exogenous IL-12. Thus, IL-12 may be limiting in PBMCs from HIV
+
but not HIV
-
individuals. These findings demonstrate that IL-12 can restore HIV
-
specific cell-mediated immunity in vitro in HIV
-
infected individuals and suggest a potential use of IL-12 in augmenting the diminished immunologic functions associated with HIV infection.
Reduced Rate of Disease Development After HIV-2 Infection as Compared to HIV-1
Authors: Marlink Richard , Kanki Phyllis , Thior Ibou , Travers Karin , Eisen Geoffrey , Siby Tidiane , Traore Ibrahima , Hsieh Chung-Cheng , Dia Mamadou Ciré , Gueye El-Hadji , Hellinger James , Guèye-Ndiaye Aissatou , Sankalé Jean-Louis , Ndoye Ibrahima , Mboup Souleymane , Essex Max
Published: October 2006

Human immunodeficiency virus type-2 (HIV-2) is a close relative of the prototype acquired immunodeficiency syndrome (AIDS) virus, HIV-1. HIV-2 is biologically similar to HIV-1, but information is lacking concerning clinical outcomes of HIV-2-infected individuals. From 1985 to 1993, a prospective clinical study was conducted in women with HIV-2 and HIV-1 infection to determine and compare rates of disease development. HIV-1-infected women had a 67% probability of AIDS-free survival 5 years after seroconversion in contrast with 100% for HIV-2-infected women. In addition to having significantly less HIV-related disease outcome in HIV-2 enrollees compared to HIV-1 enrollees, the rate of developing abnormal CD4
+
lymphocyte counts with HIV-2 infection was also significantly reduced. This natural history study demonstrates that HIV-2 has a reduced virulence compared to HIV-1.
NF-κB Controls Expression of Inhibitor IκBα: Evidence for an Inducible Autoregulatory Pathway
Authors: Sun Shao-Cong , Ganchi Parham A. , Ballard Dean W. , Greene Warner C.
Published: October 2006

The eukaryotic transcription factor nuclear factor-kappa B (NF-κB) participates in many parts of the genetic program mediating T lymphocyte activation and growth. Nuclear expression of NF-κB occurs after its induced dissociation from its cytoplasmic inhibitor IκBα. Phorbol ester and tumor necrosis factor-alpha induction of nuclear NF-κB is associated with both the degradation of performed IκBα and the activation of IκBα gene expression. Transfection studies indicate that the IκBα gene is specifically induced by the 65-kilodalton transactivating subunit of NF-κB. Association of the newly synthesized IκBα with p65 restores intracellular inhibition of NF-κB DNA binding activity and prolongs the survival of this labile inhibitor. Together, these results show that NF-κB controls the expression of IκBα by means of an inducible autoregulatory pathway.
Association of poly(CA)⋅Poly(TG) DNA Fragments into Four-Stranded Complexes Bound by HMG1 and 2
Authors: Gaillard Claire , Strauss François
Published: October 2006

The tandemly repeated DNA sequence poly(CA)⋅poly(TG) is found in tracts up to 60 base pairs long, dispersed at thousands of sites throughout the genomes of eukaryotes. Double-stranded DNA fragments containing such sequences associated spontaneously with each other in vitro, in the absence of protein, forming stable four-stranded structures that were detected by gel electrophoresis and electron microscopy. These structures were recognized specifically by the nuclear nonhistone high mobility group (HMG) proteins 1 and 2 as evidenced by gel retardation. Such sequence-specific complexes might be involved in vivo in recombination or other processes requiring specific association of two double-stranded DNA molecules.
Baboon Infant Produced by Embryo Transfer
Authors: Kraemer Duane C. , Moore Gary T. , Kramen Martin A.
Published: October 2006

An embryo was recovered surgically from a naturally ovulating, naturally inseminated
Papio cynocephalus
female on day 5 of gestation and transferred surgically to a naturally synchronized, nonmated
Papio cynocephalus
female on 20 March 1975. A male baboon weighing 875 grams was delivered by cesarean section on 5 September 1975, 174 days after estimated ovulation time.
Genetic Identification of a Hantavirus Associated with an Outbreak of Acute Respiratory Illness
Authors: Nichol Stuart T. , Spiropoulou Christina F. , Morzunov Sergey , Rollin Pierre E. , Ksiazek Thomas G. , Feldmann Heinz , Sanchez Anthony , Childs James , Zaki Sherif , Peters Clarence J.
Published: October 2006

A mysterious respiratory illness with high mortality was recently reported in the southwestern United States. Serologic studies implicated the hantaviruses, rodent-borne RNA viruses usually associated elsewhere in the world with hemorrhagic fever with renal syndrome. A genetic detection assay amplified hantavirus-specific DNA fragments from RNA extracted from the tissues of patients and deer mice (
Peromyscus maniculatus
) caught at or near patient residences. Nucleotide sequence analysis revealed the associated virus to be a new hantavirus and provided a direct genetic link between infection in patients and rodents.
Immune Responses in Interleukin-2-Deficient Mice
Authors: Kündig Thomas M. , Schorle Hubert , Bachmann Martin F. , Hengartner Hans , Zinkernagel Rolf M. , Horak Ivan
Published: October 2006

The role of costimulatory signals in T cell induction was evaluated in mice lacking the interleukin-2 (IL-2) gene. In vitro secondary antiviral T cell responses were absent unless IL-2 was added, confirming the crucial role of IL-2 in vitro. In vivo, primary and secondary cytotoxic T cell responses against vaccinia and lymphocytic choriomeningitis virus were within normal ranges. B cell reactivity to vesicular stomatitis virus was not impaired. T helper cell responses were delayed but biologically functional. Natural killer cell activity was markedly reduced but inducible. These normal in vivo immune responses in IL-2-deficient mice question the importance of IL-2 as defined by in vitro studies.
A Third Recognition Element in Bacterial Promoters: DNA Binding by the α Subunit of RNA Polymerase
Authors: Ross Wilma , Gosink Khoosheh K. , Salomon Julia , Igarashi Kazuhiko , Zou Chao , Ishihama Akira , Severinov Konstantin , Gourse Richard L.
Published: October 2006

A DNA sequence rich in (A+T), located upstream of the -10, -35 region of the
Escherichia coli
ribosomal RNA promoter
rrnB
P1 and called the UP element, stimulates transcription by a factor of 30 in vivo, as well as in vitro in the absence of protein factors other than RNA polymerase (RNAP). When fused to other promoters, such as lacUV5, the UP element also stimulates transcription, indicating that it is a separable promoter module. Mutations in the carboxyl-terminal region of the α subunit of RNAP prevent stimulation of these promoters by the UP element although the mutant enzymes are effective in transcribing the "core" promoters (those lacking the UP element). Protection of UP element DNA by the mutant RNAPs is severely reduced in footprinting experiments, suggesting that the selective decrease in transcription might result from defective interactions between α and the UP element. Purified α binds specifically to the UP element, confirming that α acts directly in promoter recognition. Transcription of three other promoters was also reduced by the COOH-terminal α mutations. These results suggest that UP elements comprise a third promoter recognition region (in addition to the -10, -35 recognition hexamers, which interact with the σ subunit) and may account for the presence of (A+T)-rich DNA upstream of many prokaryotic promoters. Since the same α mutations also block activation by some transcription factors, mechanisms of promoter stimulation by upstream DNA elements and positive control by certain transcription factors may be related.
A Covalent Enzyme-Substrate Intermediate with Saccharide Distortion in a Mutant T4 Lysozyme
Authors: Kuroki Ryota , Weaver Larry H. , Matthews Brian W.
Published: October 2006

The glycosyl-enzyme intermediate in lysozyme action has long been considered to be an oxocarbonium ion, although precedent from other glycosidases and theoretical considerations suggest it should be a covalent enzyme-substrate adduct. The mutation of threonine 26 to glutamic acid in the active site cleft of phage T4 lysozyme (T4L) produced an enzyme that cleaved the cell wall of
Escherichia coli
but left the product covalently bound to the enzyme. The crystalline complex was nonisomorphous with wild-type T4L, and analysis of its structure showed a covalent linkage between the product and the newly introduced glutamic acid 26. The covalently linked sugar ring was substantially distorted, suggesting that distortion of the substrate toward the transition state is important for catalysis, as originally proposed by Phillips. It is also postulated that the adduct formed by the mutant is an intermediate, consistent with a double displacement mechanism of action in which the glycosidic linkage is cleaved with retention of configuration as originally proposed by Koshland. The peptide part of the cell wall fragment displays extensive hydrogen-bonding interactions with the carboxyl-terminal domain of the enzyme, consistent with previous studies of mutations in T4L.
Connexin Mutations in X-Linked Charcot-Marie-Tooth Disease
Authors: Bergoffen J. , Scherer S. S. , Wang S. , Scott M. Oronzi , Bone L. J. , Paul D. L. , Chen K. , Lensch M. W. , Chance P. F. , Fischbeck K. H.
Published: October 2006

X-linked Charcot-Marie-Tooth disease (CMTX) is a form of hereditary neuropathy with demyelination. Recently, this disorder was mapped to chromosome Xq13.1. The gene for the gap junction protein connexin32 is located in the same chromosomal segment, which led to its consideration as a candidate gene for CMTX. With the use of Northern (RNA) blot and immunohistochemistry technique, it was found that connexin32 is normally expressed in myelinated peripheral nerve. Direct sequencing of the connexin32 gene showed seven different mutations in affected persons from eight CMTX families. These findings, a demonstration of inherited defects in a gap junction protein, suggest that connexin32 plays an important role in peripheral nerve.
Functional Magnetic Resonance Imaging of Motor Cortex: Hemispheric Asymmetry and Handedness
Authors: Kim Seong-Gi , Ashe James , Hendrich Kristy , Ellermann Jutta M. , Merkle Hellmut , Uğurbil Kâmil , Georgopoulos Apostolos P.
Published: October 2006

A hemispheric asymmetry in the functional activation of the human motor cortex during contralateral (C) and ipsilateral (I) finger movements, especially in right-handed subjects, was documented with nuclear magnetic resonance imaging at high field strength (4 tesla). Whereas the right motor cortex was activated mostly during contralateral finger movements in both right-handed (C/I mean area of activation = 36.8) and left-handed (C/I = 29.9) subjects, the left motor cortex was activated substantially during ipsilateral movements in left-handed subjects (C/I = 5.4) and even more so in right-handed subjects (C/I = 1.3).
Genotypic and Phenotypic Characterization of HIV-1 Patients with Primary Infection
Authors: Zhu Tuofu , Mo Hongmei , Wang Ning , Nam Daniel S. , Cao Yunzhen , Koup Richard A. , Ho David D.
Published: October 2006

Better characterization of human immunodeficiency virus-type 1 (HIV-1) in patients with primary infection has important implications for the development of an acquired immunodeficiency syndrome (AIDS) vaccine because vaccine strategies should target viral isolates with the properties of transmitted viruses. In five HIV-1 seroconverters, the viral phenotype was found to be uniformly macrophage-tropic and non-syncytium-inducing. Furthermore, the viruses were genotypically homogeneous within each patient, but a common signature sequence was not discernible among transmitted viruses. In the two cases where the sexual partners were also studied, the sequences of the transmitted viruses matched best with minor variants in the blood of the transmitters. There was also a stronger pressure to conserve sequences in gp120 than in gp41,
nef
, and p17, suggesting that a selective mechanism is involved in transmission.
Sequence and Genome Organization of a Human Small Round-Structured (Norwalk-Like) Virus
Authors: Lambden Paul R. , Caul E. Owen , Ashley Charles R. , Clarke lan N.
Published: October 2006

Small round-structured viruses (SRSVs), also known as Norwalk or Norwalk-like viruses, are the major worldwide cause of acute, epidemic nonbacterial gastroenteritis in humans. These viruses, which contain a single-stranded RNA genome, have remained refractory to molecular characterization because of the small amounts of virus in clinical samples and the absence of an animal model and an in vitro culture system. The complete genomic nucleotide sequence of an SRSV, Southampton virus, was determined. The 7696-nucleotide RNA genome encodes three open reading frames whose sequence and organization strongly support proposals that SRSVs are members of the Caliciviridae.
Colicin E1 Binding to Membranes: Time-Resolved Studies of Spin-Labeled Mutants
Authors: Shin Yeon-Kyun , Levinthal Cyrus , Levinthal Françoise , Hubbell Wayne L.
Published: October 2006

To investigate the mechanism of interaction of the toxin colicin E1 with membranes, three cysteine substitution mutants and the wild type of the channel-forming fragment were spin labeled at the unique thiol. Time-resolved interaction of these labeled proteins with phospholipid vesicles was investigated with stopped-flow electron paramagnetic resonance spectroscopy. The fragment interacts with neutral bilayers at low pH, indicating that the interaction is hydrophobic rather than electrostatic. The interaction occurs in at least two distinct steps: (i) rapid adsorption to the surface; and (ii) slow, rate-limiting insertion of the hydrophobic central helices into the membrane interior.
LIFRβ and gp130 as Heterodimerizing Signal Transducers of the Tripartite CNTF Receptor
Authors: Davis Samuel , Aldrich Thomas H. , Stahl Neil , Pan Li , Taga Tetsuya , Kishimoto Tadamitsu , Ip Nancy Y. , Yancopoulos George D.
Published: October 2006

The ciliary neurotrophic factor (CNTF) receptor complex is shown here to include the CNTF binding protein (CNTFRα) as well as the components of the leukemia inhibitory factor (LIF) receptor, LIFRβ (the LIF binding protein) and gp130 [the signal transducer of interleukin-6 (IL-6)]. Thus, the conversion of a bipartite LIF receptor into a tripartite CNTF receptor apparently occurs by the addition of the specificity-conferring element CNTFRα. Both CNTF and LIF trigger the association of initially separate receptor components, which in turn results in tyrosine phosphorylation of receptor subunits. Unlike the IL-6 receptor complex in which homodimerization of gp130 appears to be critical for signal initiation, signaling by the CNTF and LIF receptor complexes depends on the heterodimerization of gp130 with LIFRβ. Ligand-induced dimerization of signal-transducing receptor components, also seen with receptor tyrosine kinases, may provide a general mechanism for the transmission of a signal across the cell membrane.