bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Dimensional Structure of Favin: Saccharide Binding-Cyclic Permutation in Leguminous Lectins
Authors: Reeke George N. , Becker Joseph W.
Published: October 2006

The three-dimensional structure of favin, the glucose- and mannose-binding lectin of
Vicia faba
(vetch, broad bean), has been determined at a resolution of 2.8 angstroms by molecular replacement. The crystals contain specifically bound glucose and provide the first high-resolution view of specific saccharide binding in a leguminous lectin. The structure is similar to those of concanavalin A (Con A) and green pea lectin; differences from Con A show that minimal changes are needed to accommodate the cyclic permutation in amino acid sequence between the two molecules. The molecule is an ellipsoidal dimer dominated by extensive β structures. Each protomer contains binding sites for two divalent metal ions (Mn
2+
and Ca
2+
) and a specific saccharide. Glucose is bound by favin in a cleft in the molecular surface and has noncovalent contacts primarily with two peptide loops, one of which contains several metal ion ligands. The specific carbohydrate-binding site is similar to that of Con A in location and general peptide folding, despite several differences in specific amino acid residues.
The Molecular Basis of Erythrocyte Shape
Authors: Elgsaeter Arnljot , Stokke Bjorn T. , Mikkelsen Arne , Branton Daniel
Published: October 2006

Recent discoveries about the molecular organization and physical properties of the mammalian erythrocyte membrane and its associated structural proteins can now be used to explain, and may eventually be used to predict, the shape of the erythrocyte. Such explanations are possible because the relatively few structural proteins of the erythrocyte are regularly distributed over the entire cytoplasmic surface of the cell membrane and because the well-understood topological associations of these proteins seem to be stable in comparison with the time required for the cell to change shape. These simplifications make the erythrocyte the first nonmuscle cell for which it will be possible to extend our knowledge of molecular interactions to the next hierarchical level of organization that deals with shape and shape transformations.
A Critical Period for Macromolecular Synthesis in Long-Term Heterosynaptic Facilitation in
Aplysia
Authors: Montarolo P. G. , Goelet P. , Castellucci V. F. , Morgan J. , Kandel E. R. , Schacher S.
Published: October 2006

Both long-term and short-term sensitization of the gill and siphon withdrawal reflex in
Aplysia
involve facilitation of the monosynaptic connections between the sensory and motor neurons. To analyze the relationship between these two forms of synaptic facilitation at the cellular and molecular level, this monosynaptic sensorimotor component of the gill-withdrawal reflex of
Aplysia
can be reconstituted in dissociated cell culture. Whereas one brief application of 1 μ
M
serotonin produced short-term facilitation in the sensorimotor connection that lasted minutes, five applications over 1.5 hours resulted in long-term facilitation that lasted more than 24 hours. Inhibitors of protein synthesis or RNA synthesis selectively blocked long-term facilitation, but not short-term facilitation, indicating that long-term facilitation requires the expression of gene products not essential for short-term facilitation. Moreover, the inhibitors only blocked long-term facilitation when given during the serotonin applications; the inhibitors did not block the facilitation when given either before or after serotonin application. These results parallel those for behavioral performance in vertebrates and indicate that the critical time window characteristic of the requirement for macromolecular synthesis in long-term heterosynaptic facilitation is not a property of complex circuitry, but an intrinsic characteristic of specific nerve cells and synaptic connections involved in the long-term storage of information.
Catalytic Antibodies
Authors: Tramontano Alfonso , Janda Kim D. , Lerner Richard A.
Published: October 2006

Monoclonal antibodies elicited to haptens that are analogs of the transition state for hydrolysis of carboxylic esters behaved as enzymic catalysts with the appropriate substrates. These substrates are distinguished by the structural congruence of both hydrolysis products with haptenic fragments. The haptens were potent inhibitors of this esterolytic activity, in agreement with their classification as transition state analogs. Mechanisms are proposed to account for the different chemical behavior of these antibodies with two types of ester substrates. The generation of an artificial enzyme through transition state stabilization by antibodies was thus demonstrated. These studies indicate a potentially general approach to catalyst design.
Absence of Significant Cellular Dilution During ADH-Stimulated Water Reabsorption
Authors: Strange K. , Spring K. R.
Published: October 2006

Water reabsorption across many "tight" urinary epithelia is driven by large transepithelial osmotic gradients and is controlled by antidiuretic hormone (ADH). Numerous investigators have concluded that ADH-induced water reabsorption causes large apparent increases in cell volume with concomitant cytoplasmic dilution. A central question in renal physiology has been how cellular homeostasis is maintained in tight urinary epithelia during antidiuresis. Previous direct measurements of cell membrane permeability to water and the present direct measurements of cell volume in collecting tubules of rabbit kidney cortex by quantitative light microscopy show that cell volume does not change significantly during transcellular water flow. Fluid transported across the epithelium accumulated in lateral and basal intercellular spaces; the effect was an increase in cell height and tubule wall thickness accompanied by maintenance of nearly constant cell volume. The stability of cell volume is a consequence of the relatively high water permeability of the blood-facing cell membrane.
Increased Plasma Interleukin-1 Activity in Women After Ovulation
Authors: Cannon Joseph G. , Dinarello Charles A.
Published: October 2006

The polypeptide interleukin-1 mediates many host responses to infection and inflammation. A method was developed for studying interleukin-1 levels in human plasma from febrile patients. Interleukin-1 activity was also consistently found in plasma samples from women in the luteal phase of their menstrual cycle. This activity was neutralized by a specific antiserum to human interleukin-1 and was low in plasma from healthy men and preovulatory women. Thus interleukin-1 appears to have a role in normal physiological conditions as well as in disease states.
Diagnostic Ultrasound and Sister Chromatid Exchanges: Failure to Reproduce Positive Findings
Authors: Ciaravino V. , Brulfert A. , Miller M. W. , Jacobson-Kram D. , Morgan W. F.
Published: October 2006

Human lymphocytes were exposed in vitro to ultrasound from two clinical devices, one of which was previously reported to have increased the frequency of sister chromatid exchanges. The ultrasonic exposures had no significant effect on the frequency of sister chromatid exchanges from three blood donors. Exposure to ultrasound also had no effect on cell cycle progression. A concomitant positive control (mitomycin C) resulted in a significant increase in sister chromatid exchanges.
Isolation of the Gene for a Glycophorin-Binding Protein Implicated in Erythrocyte Invasion by a Malaria Parasite
Authors: Ravetch Jeffrey V. , Kochan Jarema , Perkins Margaret
Published: October 2006

Plasmodium falciparum
, the most lethal of the malarial parasites that infect humans, undergoes three cycles of development in its vertebrate host and elicits stage-specific immune responses. This stage specificity of the immune response has made it difficult to isolate antigens that would be useful in developing a vaccine against malaria. A complementary DNA clone for a glycophorin-binding protein of
Plasmodium falciparum
merozoites has been isolated and characterized. The protein interacts with glycophorin, the erythrocyte receptor, during invasion of the host cell by the parasite. Antigenic determinants of this protein expressed in Escherichia coli have been used to produce antibodies to a glycophorin-binding protein. The antibodies show schizont-specific immunofluorescence and react with the merozoite protein. The primary sequence of these determinants reveals a 150-nucleotide tandem-repeating sequence coding for a 50-amino-acid repeat. The characterization of the
Plasmodium falciparum
glycophorin-binding protein represents one approach toward designing serologic agents to block the parasite's development in the vertebrate host.
Depolarization and Muscarinic Excitation Induced in a Sympathetic Ganglion by Vasoactive Intestinal Polypeptide
Authors: Kawatani Masahito , Rutigliano Michael , de Groat William C.
Published: October 2006

The effects of vasoactive intestinal polypeptide (VIP) in the superior cervical ganglion of the cat were studied in vitro and in vivo with sucrose gap and multiunit recording, respectively. At a dose of 0.03 to 0.12 nanomole, VIP produced a dose-dependent, prolonged (3 to 15 minutes) depolarization of the ganglion and enhanced the ganglionic depolarization elicited by the muscarinic agonist acetyl-β-methylcholine. At a dose of 1.8 to 10 nanomoles, the peptide enhanced and prolonged the postganglionic discharge elicited by acetyl-β-methylcholine, enhanced muscarinic transmission in ganglia treated with an anticholinesterase agent, and enhanced the late muscarinic discharge elicited by acetylcholine. VIP did not affect the early nicotinic discharge elicited by acetylcholine or by electrical stimulation of the preganglionic nerve. It is concluded that VIP has a selective facilitatory action on muscarinic excitatory mechanisms in the superior cervical ganglion of the cat.
A
Plasmodium falciparum
Antigen that Binds to Host Erythrocytes and Merozoites
Authors: Camus Daniel , Hadley Terence J.
Published: October 2006

Antigens that bind to erythrocytes were identified in the supernatant fluids of a cultured human malaria parasite (
Plasmodium falciparum
). A 175-kilodalton (175K) antigen bound only to erythrocytes susceptible to invasion. The 175K antigen from the Camp or the FCR-3 strain also bound to merozoites. However, the antigen did not bind to merozoites when merozoites and supernatant antigens were from different strains unless proteinase inhibitors were present. Moreover, erythrocytes coated with supernatant antigens from the Camp or FCR-3 strain were invaded normally by merozoites of the homologous strain but were partially resistant to invasion by merozoites of the heterologous strain. The 175K antigen may be a receptor acting as a "bridge" between erythrocytes and merozoites.
Gene for α-Chain of Human T-Cell Receptor: Location on Chromosome 14 Region Involved in T-Cell Neoplasms
Authors: Croce Carlo M. , Isobe Masaharu , Palumbo Antonio , Puck Jennifer , Ming Jeffrey , Tweardy David , Erikson Jan , Davis Mark , Rovera Giovanni
Published: October 2006

A human complementary DNA clone specific for the α-chain of the T-cell receptor and a panel of rodent × human somatic cell hybrids were used to map the α-chain gene to human chromosome 14 in a region proximal to the immunoglobulin heavy chain locus. Analysis by means of in situ hybridization of human metaphase chromosomes served to further localize the α-chain gene to region 14q11-q12, which is consistently involved in translocations and inversions detectable in human T-cell leukemias and lymphomas. Thus, the locus for the α-chain T-cell receptor may participate in oncogene activation in T-cell tumors.
Cytosolic-Free Calcium Transients in Cultured Vascular Smooth Muscle Cells: Microfluorometric Measurements
Authors: Kobayashi Sei , Kanaide Hideo , Nakamura Motoomi
Published: October 2006

Microfluorometric recordings were made of changes in the concentration of cytosolic-free calcium in cultured rat vascular smooth muscle cells treated with quin 2, an intracellularly trapped dye, under several conditions. Nitroglycerin decreased calcium in both the presence and absence of extracellular calcium and strongly and progressively decreased the extent of transient increases in calcium induced by repeated applications of caffeine in the absence of extracellular calcium. Therefore nitroglycerin probably decreases cytosolic-free calcium by accelerating the extrusion of calcium through the sarcolemmal membrane.
Transfectomas Provide Novel Chimeric Antibodies
Authors: Morrison Sherie L.
Published: October 2006

Methods have been developed to transfect immunoglobulin genes into lymphoid cells. The transfected genes are faithfully expressed, and assembly can occur both between the transfected and endogenous chains and between two transfected chains. Gene transfection can be used to reconstitute immunoglobulin molecules and to produce novel immunoglobulin molecules. These novel molecules can represent unique combinations of heavy and light chains; alternatively, by means of recombinant DNA technology, genes can be assembled in vitro, transfected, and expressed. The end products of such manipulations include chimeric molecules with variable regions joined to different isotypic constant regions; this is possible both within and between species. It is also possible to synthesize altered immunoglobulin molecules, as well as molecules having immunoglobulin sequences fused with nonimmunoglobulin sequences (for example, enzyme sequences).
Detection of Smoking-Related Covalent DNA Adducts in Human Placenta
Authors: Everson Richard B. , Randerath Erika , Santella Regina M. , Cefalo Robert C. , Avitts Tommie A. , Randerath Kurt
Published: October 2006

The presence of covalent DNA chemical addition products (adducts) in human term placentas was investigated by recently developed immunologic and 32P-postlabeling assays. DNA from placental specimens of smokers showed a small but not statistically significant increase in adduct levels when tested by antibodies to DNA modified with a benzo[
a
]pyrene dihydrodiol epoxide (BPDE-I), the ultimate carcinogenic derivative of benzo[
a
]pyrene. The postlabeling assay detected several modified nucleotides, one of which (adduct 1) strongly related to maternal smoking during pregnancy. This adduct was present in placental tissue from 16 of 17 smokers, but only 3 of 14 nonsmokers. Among smokers, levels of adduct 1 in general were only weakly related to questionnaire and biochemical measures of the intensity of smoking exposures, which suggests modulation by individual susceptibility factors. The adduct seemed to be derived from an aromatic carcinogen, but it may not result from several of the most intensely studied polycyclic aromatic hydrocarbons or aromatic amines in tobacco smoke. The data show the association of cigarette smoking with covalent damage to human DNA in vivo.
The Cyclopean Ear: A New Sense for the Praying Mantis
Authors: Yager David D. , Hoy Ronald R.
Published: October 2006

The praying mantis, thought to be deaf, possesses a sensitive and specialized acoustic sense. Neural recordings show that the auditory system responds primarily to ultrasound between 25 and 45 kilohertz with thresholds of 55 to 60 decibels. Other insects with auditory tympana possess paired, laterally placed ears; the mantis has only a single ear that is located in the ventral midline between the metathoracic legs. Some species of mantis abruptly and dramatically alter their flight path when stimulated with ultrasonic pulses, suggesting a behavioral response to insectivorous echo-locating bats.
The Mechanism of Binding of a Polynucleotide Chain to Pancreatic Ribonuclease
Authors: McPherson Alexander , Brayer Gary , Cascio Duilio , Williams Roger
Published: October 2006

The crystalline complex of pancreatic ribonuclease (RNase) with oligomers of d(pA)
4
has been solved by x-ray diffraction methods and refined by standard procedures to a conventional crystallographic R factor of 0.22 at 2.5 angstrom resolution. The asymmetric unit is a complex of one RNase molecule associated with four d(pA)
4
oligomers. Although the DNA in this complex is segmented, and therefore shows some discontinuities, it nevertheless traces a continuous path 12 nucleotides in length that passes through the active site cleft of the enzyme and over the surface of the protein. The DNA makes a series of eight to nine electrostatic bonds between its phosphate groups and lysine and arginine residues on the protein, as well as specific chemical interactions at the active site. The path described by the sequence of nucleotides is likely to be that taken by an extended polynucleotide chain when it is bound by the enzyme.
Direct Imaging of Live Human Platelets by Flash X-Ray Microscopy
Authors: Feder Ralph , Banton Veronica , Sayre David , Costa John , Baldini Mario , Kim Byung
Published: October 2006

A 100-nanosecond pulse of long-wavelength x-rays was used to produce high-resolution stop-motion images of living human platelets. Although some aspects of the structure conform to those seen in dehydrated specimens, novel features are apparent. The technique should permit detailed stop-motion examination of the interaction of platelets with their surrounding medium as well as exploration of the phagocytic and secretory activities of a wide variety of other cells.
Functional Properties of Individual Neuronal Branches Isolated in Situ by Laser Photoinactivation
Authors: Jacobs Gwen A. , Miller John P.
Published: October 2006

The functional properties of an isolated dendritic branch of an identified sensory interneuron in the cricket were studied. The branch responded to wind stimuli directed at the animal and displayed a distinct directional sensitivity to those stimuli. A technique was used that allows a neuron to be specifically lesioned in a semi-intact preparation during intracellular recording. Lesioning was achieved by dye-sensitized photoinactivation with a laser epi-illumination stereomicroscope.
Structure, Dynamics, and Reactivity in Hemoglobin
Authors: Friedman Joel M.
Published: October 2006

The static structure of hemoglobin and its functional properties are very well characterized. It is still not known how energy is stored and used within the structure of the protein to promote function and functional diversity. An essential part of this question is understanding the mechanism through which the overall protein structure (quaternary structure) couples to the local environment about the oxygen binding sites. Time-resolved resonance Raman spectroscopy has been used to probe the vibrational degrees of the freedom of the binding site as a function of protein structure. Comparison of the spectra from both equilibrium and transient forms of deoxy hemoglobin from a variety of mammalian, reptilian, and fish hemoglobins reveals that for each quaternary structure there exist two tertiary states stabilized by the presence or absence of an iron-bound ligand. Pulse-probe Raman experiments show that for photodissociated, ligated hemoglobins the local tertiary structure relaxes at a solution-dependent rate extending from tens of nanoseconds to microseconds. In this local environment, the linkage between the iron and the proximal histidine proves to be the single observed structural feature that responds in a systematic and substantial manner to structural changes in the protein. The additional finding of a correlation between the frequency of the iron-proximal histidine stretching motion (ν
Fe-His
) and various parameters of ligand reactivity, including geminate recombination, implicates the associated localized structural element in the mechanism of protein control of ligand binding. On the basis of these and related finds, a model is presented to account for both coarse and fine control of ligand binding by the protein structure.
The Mechanism of Irreversible Enzyme Inactivation at 100°C
Authors: Ahern Tim J. , Klibanov Alexander M.
Published: October 2006

The mechanism of irreversible thermoinactivation of an enzyme has been quantitatively elucidated in the pH range relevant to enzymatic catalysis. The processes causing irreversible inactivation of hen egg-white lysozyme at 100°C are deamidation of asparagine residues, hydrolysis of peptide bonds at aspartic acid residues, destruction of disulfide bonds, and formation of incorrect (scrambled) structures; their relative contributions depend on the
p
H.
Genetic Rescue of a Lethal "Null" Activity Allele of 6-Phosphogluconate Dehydrogenase in
Drosophila melanogaster
Authors: Hughes M. Beatrice , Lucchesi John C.
Published: October 2006

While a null activity mutant allele of the structural gene for 6-phosphogluconate dehydrogenase in
Drosophila melanogaster
is lethal, a similar mutation for glucose-6-phosphate dehydrogenase is not. Double mutant combinations lacking both enzyme activities, obtained either by recombination or by mutagen treatment of a chromosome bearing the lethal allele, result in a restoration of viability. The indispensability of the pentose phosphate shunt in
Drosophila
appears to depend upon the specific position of the block within the pathway.
Projective Imaging of Pulsatile Flow with Magnetic Resonance
Authors: Wedeen Van J. , Meuli Reto A. , Edelman Robert R. , Geller Stuart C. , Frank Lawrence R. , Brady Thomas J. , Rosen Bruce R.
Published: October 2006

Noninvasive angiography with magnetic resonance is demonstrated. Signal arising in all structures except vessels that carry pulsatile flow is eliminated by means of velocity-dependent phase contrast, electrocardiographic gating, and image subtraction. Background structures become in effect transparent, enabling the three-dimensional vascular tree to be imaged by projection to a two-dimensional image plane. Image acquisition and processing are accomplished with entirely conventional two-dimensional Fourier transform magnetic resonance imaging techniques. When imaged at 0.6 tesla, vessels 1 to 2 millimeters in diameter are routinely detected in a 50-centimeter field of view with data acquisition times less than 15 minutes. Studies of normal and pathologic anatomy are illustrated in human subjects.
Potency in Male Rhesus Monkeys: Effects of Continuously Receptive Females
Authors: Michael Richard P. , Zumpe Doris
Published: October 2006

Ejaculations decreased and mount latencies increased when intact males were paired regularly over a 3.5-year period (3180 tests) with ovariectomized females made constantly receptive by daily injections of estradiol. The deterioration in potency was abruptly and completely reversed by substituting a group of new but similarly treated females for the original ones.
Liposomes and Local Hyperthermia: Selective Delivery of Methotrexate to Heated Tumors
Authors: Weinstein J. N. , Magin R. L. , Yatvin M. B. , Zaharko D. S.
Published: October 2006

Liposomes with phase transitions a few degrees above physiological temperature delivered more than four times as much methotrexate to murine tumors heated to 42°C as to unheated control tumors. Most of the accumulated drug appeared to be intracellular and bound to dihydrofolate reductase, the enzyme blocked by methotrexate in its role as an antineoplastic agent.
Cement Line Motion in Bone
Authors: Lakes Roderic , Saha Subrata
Published: October 2006

Compact bovine bone subjected to constant torsional load for long periods of time exhibits large anelastic effects. Displacements occur at the cement lines and are responsible for part or all of the long-term deformation. The absence of an asymptotic creep strain is consistent with an interpretation of the cement line as a viscous interface.
Local Cerebral Glucose Metabolism During Controlled Hypoxemia in Rats
Authors: Pulsinelli William A. , Duffy Thomas E.
Published: October 2006

2-Deoxy-[
14
C]glucose metabolism was examined in brains of hypoxic, normotensive rats by autoradiography, which revealed alternating cortical columns of high and low metabolism. Activity in white matter was increased severalfold over that in adjacent gray matter. The columns were anatomically related to penetrating cortical arteries with areas between arteries demonstrating higher rates of metabolism. The results suggest the presence of interarterial tissue oxygen gradients that influence regional glucose metabolism. The relatively greater sensitivity of white matter metabolism to hypoxia may lead to an understanding of white matter damage in postanoxic leukoencephalopathy.
Hippocampal Afterdischarges: Differential Spread of Activity Shown by the [
14
C]Deoxyglucose Technique
Authors: Kliot Michel , Poletti Charles E.
Published: October 2006

Differential spread of afterdischarge activity initiated electrically in ventral and dorsal parts of the hippocampal formation was studied by the [
14
C]deoxyglucose technique in rats. Afterdischarges initiated in either the ventral or dorsal hippocampal formation, without activation of the ventral subicular cortex, increased glucose utilization in the lateral septum. In contrast, afterdischarges initiated by direct activation of the ventral subicular cortex increased glucose utilization in extensive areas of the ipsilateral amygdala, claustrum, hypothalamus, preoptic region, and basal forebrain.
The Oilbird: Hearing and Echolocation
Authors: Konishi Masakazu , Knudsen Eric I.
Published: October 2006

Oilbirds can navigate in total darkness by echolocation. The sound energy in their sonar cries is unevenly distributed over the range from about 1 to 15 kilohertz, with a dominant frequency range of 1.5 to 2.5 kilohertz. This corresponds to the most sensitive range of their hearing as determined by neurophysiological methods. Behavioral tests in their home cave indicate that the smallest object avoided by them is a disk 20 centimeters in diameter.
On the Specificity of Kainic Acid
Authors: Mason S. T. , Fibiger H. C.
Published: October 2006

The specificity of the neurotoxic agent, kainic acid, for destroying cell bodies while sparing terminals and fibers of passage was examined by infusing this agent into the axons of the dorsal noradrenergic bundle and measuring the degree of depletion of noradrenaline concentrations and the reduction in noradrenaline uptake in cortex and hippocampus. Extensive neuronal loss and gliosis were observed around the injection site. In addition, a significant and consistent 25 percent depletion of hippocampal-cortical noradrenaline was also obtained. The results suggest that although kainic acid has its greatest destructive action on neuronal perikarya, a significant amount of damage to axons of passage may also occur.
Cholinergic Neuronotrophic Factors: Intraocular Distribution of Trophic Activity for Ciliary Neurons
Authors: Adler R. , Landa K. B. , Manthorpe M. , Varon S.
Published: October 2006

Chick ciliary ganglionic neurons require an interaction with their peripheral targets for survival during a critical period of their embryonic development in vivo. It has recently been shown that survival of these neurons in dissociated cell cultures is supported by extract from whole chick embryo. In this study, an assay system based on microwell cultures of ciliary ganglionic neurons was used to demonstrate that a very rich source of trophic factor for them is the intraocular target tissues they innervate. Out of 8000 trophic units present in a 12-day embryo, 2500 were contained in the eye. A subdissection of the eye showed its activity to be localized in a fraction containing the ciliary body and choroid coat, with a specific activity almost 20-fold higher than that of the whole embryo. This selective intraocular distribution at a time when survival or death of ciliary ganglionic neurons is decided in vivo suggests that this soluble factor may be involved in the normal development of the ciliary ganglion.
Goldfish Retina: A Correlate Between Cone Activity and Morphology of the Horizontal Cell in Clone Pedicules
Authors: Raynauld Jean-Pierre , Laviolette John R. , Wagner Hans-Joachin
Published: October 2006

In the cone pedicules, the digitations of horizontal cell process lateral to the synaptic ribbon disappear after dark adaptation. This disappearance is correlated with the loss of color opponency and cone function shown in ganglion cell recordings in isolated retinas. Cone function and color-opponent responses are restored by reapplying background light.
Sucrose Consumption Early in Life Fails to Modify the Appetite of Adult Rats for Sweet Foods
Authors: Wurtman Judith J. , Wurtman Richard J.
Published: October 2006

Male rats consumed a diet containing 0, 12, or 48 percent sucrose on days 16 to 30 of life. Thereafter, they had simultaneous access to all three diets until day 63. No relationship was detected between sucrose consumption early in life and subsequent preference for sucrose. The onset of puberty was associated with a decreased appetite for sucrose among animals of both sexes.
On the "Rawness" of Subsoils
Authors: Lipman Chas. B.
Published: October 2006

Subsoils of arid regions are certainly no less "raw" than those of semi-arid regions, and probably only slightly less so than those of humid regions.

2. If, as seems as yet unproved, inoculated legume seeds fail to develop on humid subsoil material, such failure can not justifiably be attributed as is done by Alway, McDole and Rost, to a lack of available phosphoric acid and potash.

3. A lack of available nitrogen probably is sufficient to account for rawness of subsoils.

4. The poor aeration of subsoils which indirectly results in their rawness, may be accounted for more simply than by Hilgard's explanation of the washing down of fine particles into the subsoil, which prevents proper aeration.
Elevated Salivary and Synovial Fluid β
2
-Microglobulin in Sjogren's Syndrome and Rheumatoid Arthritis
Authors: Talal Norman , Grey Howard M. , Zvaifler Nathan , Michalski Joseph P. , Daniels Troy E.
Published: October 2006

β
2
-Microglobulin is normally present in low concentrations in serum and other bodily fluids. By use of a radioimmunoassay, elevated concentrations of β
2
-microglobulin were found in saliva and synovial fluid from patients with Sjogren's syndrome and rheumatoid arthritis, autoimmune inflammatory diseases that attack and destroy the salivary glands and articular tissues, respectively. Elevated β
2
-microglobulin concentrations decreased in the saliva of two patients who simultaneously showed a clinical response to systemic treatment. Measurement of β
2
-microglobulin in inflammatory fluids may offer a simple method of quantifying local activity in autoimmune states.
Mechanism of Axonal Transport: A Proposed Role for Calcium Ions
Authors: Hammerschlag Richard , Dravid Anant R. , Chiu Arlene Y.
Published: October 2006

In vitro axonal transport of tritiated protein decreased 40 to 60 percent when neuronal cell bodies were incubated in calcium-free medium, but was not affected when only nerve trunks were exposed to calcium-free conditions. In addition, calcium-45 was transported along axons at a rate similar to that of rapidly transported tritiated protein. These data are interpreted to suggest that calcium ions are involved in the initiation of axonal transport and in the coupling of transported proteins to the transport system.
Plasma β-Endorphin Immunoreactivity in Schizophrenia
Authors: Ross Maureen , Berger Philip A. , Goldstein Avram
Published: October 2006

Plasma β-endorphin-like immunoreactivity was measured by a method that was equally sensitive to β-endorphin and [Leu
5
]-β-endorphin. Immunoreactivity in 98 schizophrenic patients did not differ greatly from that in 42 normal subjects. No immunoreactivity was detectable in dialyzates from first-time hemodialysis of eight nonpsychotic renal patients and nine schizophrenic patients. These results are not compatible with recent reports of extremely high concentrations of [Leu
5
]-β-endorphin in hemodialyzates from schizophrenic patients.
Pupillary Responses During Information Processing Vary with Scholastic Aptitude Test Scores
Authors: Ahern Sylvia , Beatty Jackson
Published: October 2006

The magnitude of task-evoked pupillary dilations during mental activity has previously been shown to index the cognitive capacity utilized in the performance of the mental task. To determine the relation between "intelligence" and capacity demands during mental activity, task-evoked pupillary dilations were measured while two groups of university students differing in their scores on the Scholastic Aptitude Test solved mental arithmetic problems. Over three levels of problem difficulty, more intelligent subjects showed smaller task-evoked pupillary dilations than did their less intelligent counterparts. Thus, the more intelligent appear to possess more efficient cognitive structures of information processing. These data provide evidence that physiological differences between individuals of differing psychometric intelligence emerge during mental activity.
Hydrostatic Pressure Reversibly Blocks Membrane Control of Ciliary Motility in
Paramecium
Authors: Otter T. , Salmon E. D.
Published: October 2006

A hydrostatic pressure of only 68 atmospheres prevented swimming
Paramecium caudatum
from "avoiding" or reversing direction; 170 atmospheres stopped or decreased forward velocity by more than 75 percent. A decompression of 40 atmospheres invoked a single reversal, even at 280 atmospheres. In contrast, 170 atmospheres did not significantly affect swimming behavior of paramecium "models" that were reactivated in a solution containing adenosine triphosphate and magnesium ions after their membranes had been disrupted by Triton X-100.
End-Capillary Loops in the Heart: An Explanation for Discrete Myocardial Infarctions Without Border Zones
Authors: Okun Ellen M. , Factor Stephen M. , Kirk Edward S.
Published: October 2006

Separate perfusions of canine coronary arteries with colored silicone-rubber compound reveal that in the region where two microcirculations abut, capillaries derived from individual large vessels are discrete, with no interconnections. Terminal homologous capillaries form loops rather than anastomosing with heterologous capillaries. This anatomic arrangement may account for discrete myocardial infarctions without ischemic border zones.
Water, Protein Folding, and the Genetic Code
Authors: Wolfenden R., V. , Cullis P. M. , Southgate C. C. F.
Published: October 2006

The absolute affinities of amino acid side chains for solvent water closely match their relative distributions between the surface and the interior of native proteins and are associated with a remarkable bias in the genetic code.
Metabolism of Theophylline to Caffeine in Human Fetal Liver
Authors: Aranda Jacob V. , Louridas A. Tom , Vitullo Benedetto B. , Thom Philip , Aldridge Andrew , Haber Richard
Published: October 2006

Caffeine (1,3,7-trimethylxanthine) is a biotransformation product of theophylline (1,3-dimethylxanthine) in the human fetus. Liver explants, obtained from human fetuses with gestational ages of 12 to 20 weeks, were incubated with theophylline and produced caffeine and, in lesser amounts, 1,3-dimethyluric acid and 3-methylxanthine. These findings suggest that the predominant pathway in theophylline metabolism in the fetus and newborn infant is the methylation reaction producing caffeine. This may contribute to the neonate's exceedingly slower elimination of caffeine relative to theophylline. Caffeine produced from theophylline may add to the pharmacologic effects of theophylline in newborn infants with apnea.
Immunoreactive Vasopressin and Oxytocin: Concentration in Individual Human Hypothalamic Nuclei
Authors: George Jack M.
Published: October 2006

Individual hypothalamic nuclei were microdissected from brain tissue of ten human subjects who had died suddenly while in apparent good health. Appreciable amounts of vasopressin and oxytocin immunoreactivity were found by specific radioimmunoassay in six hypothalamic nuclei including supraoptic and paraventricular nuclei. Vasopressin and oxytocin are presumed to be synthesized in supraoptic and paraventricular nuclei for axonal transport to the posterior pituitary for storage and release. Vasopressin and oxytocin in other hypothalamic nuclei may be a part of this system of neurosecretion or may serve some other function.
Defective Phagocytosis of Isolated Rod Outer Segments by RCS Rat Retinal Pigment Epithelium in Culture
Authors: Edwards Ross B. , Szamier R. Bruce
Published: October 2006

Retinal pigment epithelium cultured from normal rats phagocytizes large amounts of rod outer segment fragments isolated from normal rats and from RCS rats with inherited retinal degeneration. Cultured RCS rat pigment epithelium rarely ingests outer segment material, although the cells extend cellular processes around fragments of either type. Both normal and RCS pigment epithelium phagocytize polystyrene spheres. This demonstrates that RCS rat pigment epithelial cells contain a defect in the mechanism for phagocytizing outer segments.
Dieldrin-Induced Mortality in an Endangered Species, the Gray Bat (
Myotis grisescens
)
Authors: Clark Donald R. , LaVal Richard K. , Swineford Douglas M.
Published: October 2006

Brains of juvenile gray bats,
Myotis grisescens
, found dead beneath maternity roosts in two Missouri caves contained lethal concentrations of dieldrin. One colony appeared to be abnormally small, and more dead bats were found a year after the juvenile bats had been collected. This is the first report to link the field mortality of bats directly to insecticide residues acquired through the food chain.
Selective Phospholipid Adsorption and Atherosclerosis
Authors: Gershfeld Norman L.
Published: October 2006

Disaturated (fully saturated) lecithins adsorb onto solid surfaces more readily than lecithins in which one or both fatty acids are unsaturated. If saturated lecithins adsorb to arterial walls as they do to glass and polystyrene surfaces, there may be increased probability of atherosclerosis when the disaturated lecithin content of plasma is elevated. Analyses of lecithins in plasma samples from patients with myocardial infarction, and from patients with premature atherosclerosis but with low concentrations of plasma cholesterol and triglycerides, are consistent with the hypothesis that a high concentration of disaturated lecithin in plasma may be a significant risk factor for atherosclerosis, independent of triglyceride and cholesterol concentrations.
Alteration of T-Cell Functions by Infection with HTLV-I or HTLV-II
Authors: Popovic M. , Flomenberg N. , Volkman D. J. , Mann D. , Fauci A. S. , Dupont B. , Gallo R. C.
Published: October 2006

Two functionally different types of human T-cell clones, one with helper function and two with specific cytotoxic activity, were infected with different isolates of HTLV-I and HLTV-II. Both types of human T cells showed alterations in specific function after infection with either of the HTLV subgroups. Before HTLV infection, the T-cell clone with helper function proliferates and provides "help" to B cells only in the presence of both a specific soluble antigen (keyhole limpet hemocyanin) and histocompatible antigen-presenting cells. After HTLV infection, these cells respond with increased proliferation and indiscriminant stimulation of polyclonal immunoglobulin production by B cells, regardless of the histocompatibility of the antigen-presenting cells or the presence of the soluble antigen. Infection of the normal cytotoxic T-cell clones led to a dimunition or loss of the cytotoxic function. The results of these studies suggest some possible mechanisms for induction of immune deficiency and of polyclonal B-cell activation by viruses of the HTLV family.
Growth Inhibitor from BSC-1 Cells Closely Related to Platelet Type β Transforming Growth Factor
Authors: Tucker Ronald F. , Shipley Gary D. , Moses Harold L. , Holley Robert W.
Published: October 2006

Purified growth inhibitor from BSC-1 cells and type β transforming growth factor from human platelets are shown to have nearly identical biological activity and to compete for binding to the same cell membrane receptor. These findings suggest that the growth inhibitor and the type β transforming growth factor are similar molecules. The data also show that the same purified polypeptide can either stimulate or inhibit cell proliferation depending on the experimental conditions.
Novel Pharmacology of Substance K-Binding Sites: a Third Type of Tachykinin Receptor
Authors: Buck Stephen H. , Burcher Elizabeth , Shults Clifford W. , Lovenberg Walter , O'Donohue Thomas L.
Published: October 2006

The tachykinins are a family of peptides with the carboxyl terminal amino acid sequence Phe-X-Gly-Leu-Met- NH
2
. Three major mammalian tachykinins have been identified—substance K, neuromedin K, and substance P—but only two tachykinin receptors have been postulated. Three tachykinins were labeled with radioiodinated Bolton-Hunter reagent and their binding characteristics were determined in crude membrane suspensions from several tissues. In cerebral cortex labeled eledoisin exhibited high-affinity binding that was inhibited by tachykinins in a manner indicating a definitive SP-E receptor site. In gastrointestinal smooth muscle and bladder, high-affinity binding of labeled substance P was inhibited in a pattern indicating a definitive SP-P site. In intestinal smooth muscle and bladder, however, labeled substance K and labeled eledoisin were both bound in a pattern indicating a preference for substance K itself. The results suggest the existence of three distinct types of tachykinin receptors: SP-P, SP-E, and SP-K.
Characterization and Molecular Cloning of a Human Parvovirus Genome
Authors: Cotmore Susan F. , Tattersall Peter
Published: October 2006

The genome of the small human virus serologically associated with erythrocyte aplasia and erythema infectiosum (fifth disease) is shown to be a linear, nonpermuted, single-stranded DNA molecule with self-priming hairpin termini, properties which are characteristic of the genomes of the family Parvoviridae. This human parvovirus chromosome was molecularly cloned into bacterial plasmid vectors and the cloned DNA was used to explore its relatedness to other mammalian parvovirus serotypes by DNA:DNA hybridization. It is not related to the human adeno-associated viruses but does show a distant evolutionary relationship to genomes of the helper-independent parvoviruses of rodents. This strongly suggests that it is an autonomous parvovirus, and as such is the first example of a member of this group of common animal pathogens to cause disease in man.
A
trans
-Acting Product Needed for P Factor Transposition in
Drosophila
Authors: Engels William R.
Published: October 2006

A transposable genetic element of the P family in
Drosophila melanogaster
was found to be unstable in the presence of other P elements but stable in their absence. A sensitive assay for P transpositional activity is provided by the
sn
w
allele, a defective P insert in the singed bristle locus which becomes hypermutable only in the presence of complete elements. This measure of activity was highly correlated with a type of female sterility normally associated with P activity. There was no cross-reactivity with transposase from another hybrid dysgenesis-causing element (the I factor).
"Transdifferentiation" of C6 Glial Cells in Culture
Authors: Parker Keith K. , Norenberg Michael D. , Vernadakis Antonia
Published: October 2006

The activities of cyclic nucleotide phosphohydrolase, an enzyme marker for oligodendrocytes, and glutamine synthetase, an enzyme marker for astrocytes, were studied at early (21 to 26) and late (82 to 88) cell passages. The activity of cyclic nucleotide phosphohydrolase was markedly high and that of glutamine synthetase was low in the early passages, but this relation was reversed in the late passages. These findings suggest a "transdifferentiation" of C6 glial cells with passage in culture.
Lectins Mimic Insulin in the Induction of Tyrosine Aminotransferase
Authors: Smith Jonathan David , Liu Alice Y.-C.
Published: October 2006

Various lectins were found to induce tyrosine aminotransferase in H-35 rat hepatoma cells grown in monolayer culture. Wheat germ agglutinin gave a maximal induction of tyrosine aminotransferase 6 hours after its addition. The induction time course was similar to that elicited by insulin. Fourteen micrograms of wheat germ agglutinin per milliliter gave half-maximal enzyme induction and 50 micrograms per milliliter gave the maximal response. The induction of tyrosine aminotransferase by wheat germ agglutinin was additive with the induction by either dexamethasone or dibutyryl adenosine 3′,5′-monophosphate, but was not additive with the tyrosine aminotransferase induction by insulin. Wheat germ agglutinin also mimicked insulin in the inhibition of cellular protein degradation in the absence of serum. The insulin-like effects of lectins should be considered in lectin-mediated manipulations such as agglutination.
Opiates and Pain Pathways: Demonstration of Enkephalin Synapses on Dorsal Horn Projection Neurons
Authors: Ruda M. A.
Published: October 2006

The participation of the opiate peptide enkephalin in the neural circuitry of the dorsal horn was examined at the light and ultrastructural level through the use of the combined techniques of immunocytochemistry and retrograde transport of horseradish peroxidase. Enkephalin immunoreactive axonal endings made direct synaptic contact with the soma and proximal dendrites of dorsal horn thalamic projection neurons. This observation demonstrates that one major synaptic site of enkephalin modulation of the transfer of nociceptive information in the dorsal horn is on the projection neurons themselves.
Dynorphin and Vasopressin: Common Localization in Magnocellular Neurons
Authors: Watson S. J. , Akil H. , Fischli W. , Goldstein A. , Zimmerman E. , Nilaver G. , van Wimersma Griedanus T. B.
Published: October 2006

The opioid peptide dynorphin is widely distributed in neuronal tissue of rats. By immunocytochemical methods, it was shown previously that dynorphin-like immunoreactivity is present in the posterior pituitary and the cells of the hypothalamic neurosecretory magnocellular nuclei which also are responsible for the synthesis of oxytocin, vasopressin, and their neurophysins. By using an affinity-purified antiserum to the non-enkephalin part of the dynorphin molecule it has now been demonstrated that dynorphin and vasopressin occur in the same hypothalamic cells of rats, whereas dynorphin and oxytocin occur in separate cells. Homozygous Brattleboro rats (deficient in vasopressin) have magnocellular neurons that contain dynorphin separate from oxytocin. Thus dynorphin and vasopressin, although they occur in the same cells, appear to be under separate genetic control and presumably arise from different precursors.
Vasoactive Intestinal Polypeptide and Muscarinic Receptors: Supersensitivity Induced by Long-Term Atropine Treatment
Authors: Hedlund Britta , Abens Janis , Bartfai Tamas
Published: October 2006

Long-term treatment of rats with atropine induced large increases in the numbers of muscarinic receptors and receptors for vasoactive intestinal polypeptide in the salivary glands. Since receptors for vasoactive intestinal polypeptide coexist with muscarinic receptors on the same neurons in this preparation, the results suggest that a drug that alters the sensitivity of one receptor may also affect the sensitivity of the receptor for a costored transmitter and in this way contribute to the therapeutic or side effects of the drugs.