bluuebunny/crossref_metadata_2025 huggingface dataset:
Computer Analysis of Reflex Control and Organization: Respiratory Sinus Arrhythmia
Authors: Clynes Manfred
Published: October 2006

Respiratory sinus arrhythmia in waking man is described by differential equations which relate thorax circumference acceleration to instantaneous heart rate. Consequent experiments show that the arrhythmia is initiated by stretch receptors within the thorax rather than by hemodynamic or central factors, and that it is due mainly to superimposed biphasic inspiratory heart rate transients of about 15 seconds' duration. Analysis of respiration heart rate reflex provides a new quantitative physiological tool.
Viruses Associated with Epidemic Hemorrhagic Fevers of the Philippines and Thailand
Authors: Hammon W. McD. , Rundnick A. , Sather G. E.
Published: October 2006

Epidemiologic, clinical, and etiologic studies were carried out on a newly recognized, frequently fatal, pediatric disease syndrome which occurred in urban areas infested with
Aedes aegypti
mosquitoes. Four types of dengue virus (two of which are new), chikungunya virus, and another virus yet to be identified were isolated from the blood of patients. Dengue viruses, types 2 and 3, were isolated from the mosquitoes. Ample serologic confirmation was obtained of concurrent hemorrhagic fever and infection with one or more of these viruses. Thus, it was discovered that viruses of previously recognized types and of closely related new types apparently have etiologic roles in a new and highly dangerous epidemic disease syndrome.
Colloidal Silica as a Standard for Measuring Absolute Fluorescence Yield
Authors: Hercules David M. , Frankel Henry
Published: October 2006

The use of colloidal silica as a standard for fluorescence efficiency measurements is proposed. Its advantages over glycogen as a standard are availability, purity, and stability. Absolute fluorescence yields are reported for a number of substances and compared with values in the literature.
Decarboxylase Inhibition and Blood Pressure Reduction by α-Methyl-3,4-Dihydroxy-DL-phenylalanine
Authors: Oates J. A. , Gillespie L. , Udenfriend S. , Sjoerdsma A.
Published: October 2006

α-Methyl-3,4-dihydroxy-DL-phenylalanine has been found to be an effective inhibitor of aromatic amino acid decarboxylation in man. This was shown by decreased formation of serotonin, tryptamine, and tyramine from the precursor amino acids. Reduction of amine biosynthesis is associated with lowering of blood pressure in hypertensive patients and a transient sedative effect.
Participation of Non-Zinc Finger Residues in DNA Binding by Two Nuclear Orphan Receptors
Authors: Wilson Thomas E. , Paulsen Ragnhild E. , Padgett Kerstien A. , Milbrandt Jeffrey
Published: October 2006

Steroid-thyroid hormone receptors typically bind as dimers to DNA sequences that contain repeated elements termed half-sites. NGFI-B, an early response protein and orphan member of this receptor superfamily, binds to a DNA sequence that contains only one half-site (5′-AAAGGTCA-3′). A domain separate from the NGFI-B zinc fingers, termed the A box, was identified and is required for recognition of the two adenine-thymidine (A-T) base pairs at the 5′ end of the NGFI-B DNA binding element. In addition, a domain downstream of the zinc fingers of the orphan receptor H-2 region II binding protein, termed the T box, determined binding to tandem repeats of the estrogen receptor half-site (5′-AGGTCA-3′).
Osmotic Pressure and Aqueous Humor Formation in Dogfish
Authors: Doolittle Russell F. , Thomas Cynthia , Stone William
Published: October 2006

Comparative chemical analyses show the aqueous humor of smooth dogfish has lower concentrations of urea and trimethylamine oxide than the blood plasma. Freezing-point depression determinations demonstrate that the aqueous humor has a correspondingly lower osmotic pressure. It would appear that water entering the aqueous humor from the plasma is moving against an osmotic gradient.
Pupil Size as Related to Interest Value of Visual Stimuli
Authors: Hess Eckhard H. , Polt James M.
Published: October 2006

Increases in the size of the pupil of the eye have been found to accompany the viewing of emotionally toned or interesting visual stimuli. A technique for recording such changes has been developed, and preliminary results with cats and human beings are reported with attention being given to differences between the sexes in response to particular types of material.
Spring Peak of Strontium-90 Fallout
Authors: Kuroda P. K. , Hodges H. L. , Fry L. M.
Published: October 2006

An increasing trend of Sr
90
concentration in rain observed at Fayetteville, Ark., after November 1959, indicates that the seasonal and global movements of stratospheric air masses, such as described by Brewer and Dobson, play an important role in causing the spring peaks of the Sr
90
fallout.
Distribution of Phage Groups of
Staphylococcus aureus
in the Years 1927 through 1947
Authors: Blair John E. , Carr Miriam
Published: October 2006

The phage typing patterns of 194 typable strains of
Staphylococcus aureus
isolated in the years 1927 through 1947 and preserved as stock cultures revealed that 43 strains were of phage type 80/81. The occurrence of other typable strains in the broad phage groups I, II, and III corresponded closely to the frequency distribution of staphylococci reported in 1945 by Wilson and Atkinson.
Properties of the Major Component of a Peptic Digest of Rabbit Antibody
Authors: Nisonoff A. , Wissler F. C. , Lipman L. N.
Published: October 2006

The molecular weight of the active, major component isolated from a peptic digest of rabbit antibody was found to be 106,000. After treatment with a disulfide-splitting reagent, the molecular weight was 56,000, and the products migrated as a single peak in the ultracentrifuge. The univalent fragments thus formed can be partially recombined by passage through IR-120 cation-exchange resin at room temperature or by treatment with a difunctional organic mercurial. Some splitting of the pepsin-treated antibody molecule occurs on carboxymethylcellulose at
p
H 5.4.
Structure and Functional Expression of an ω-Conotoxin-Sensitive Human N-Type Calcium Channel
Authors: Williams Mark E. , Brust Paul F. , Feldman Daniel H. , Patthi Saraswathi , Simerson Susan , Maroufi Azarnoush , McCue Ann F. , Veliçelebi Gönül , Ellis Steven B. , Harpold Michael M.
Published: October 2006

N-type calcium channels are ω-conotoxin (ω-CgTx)-sensitive, voltage-dependent ion channels involved in the control of neurotransmitter release from neurons. Multiple subtypes of voltage-dependent calcium channel complexes exist, and it is the α
1
subunit of the complex that forms the pore through which calcium enters the cell. The primary structures of human neuronal calcium channel α
1B
subunits were deduced by the characterization of overlapping complementary DNAs. Two forms (α
1B-1
and α
1B-2
) were identified in human neuroblastoma (IMR32) cells and in the central nervous system, but not in skeletal muscle or aorta tissues. The α
1B-1
subunit directs the recombinant expression of N-type calcium channel activity when it is transiently co-expressed with human neuronal β
2
and α
2b
subunits in mammalian HEK293 cells. The recombinant channel was irreversibly blocked by ω-CgTx but was insensitive to dihydropyridines. The α
1B-1
α
2b
β
2
-transfected cells displayed a single class of saturable, high-affinity (dissociation constant = 55 pM) ω-CgTx binding sites. Co-expression of the β
2
subunit was necessary for N-type channel activity, whereas the α
2b
subunit appeared to modulate the expression of the channel. The heterogeneity of α
1b
subunits, along with the heterogeneity of α
2
and β subunits, is consistent with multiple, biophysically distinct N-type calcium channels.
Selective Role of N-Type Calcium Channels in Neuronal Migration
Authors: Komuro Hitoshi , Rakic Pasko
Published: October 2006

Analysis of neuronal migration in mouse cerebellar slice preparations by a laser scanning confocal microscope revealed that postmitotic granule cells initiate their migration only after the expression of N-type calcium channels on their plasmalemmal surface. Furthermore, selective blockade of these channels by addition of ω-conotoxin to the incubation medium curtailed cell movement. In contrast, inhibitors of L- and T-type calcium channels, as well as those of sodium and potassium channels, had no effect on the rate of granule cell migration. These results suggest that N-type calcium channels, which have been predominantly associated with neurotransmitter release in adult brain, also play a transient but specific developmental role in directed migration of immature neurons before the establishment of their synaptic circuits.
Ticks from European-Asiatic Birds Migrating through Egypt into Africa
Authors: Hoogstraal Harry , Kaiser Makram N.
Published: October 2006

From 321 of 7381 birds (28 species), 504 immature European-Asiatic ticks were collected:
Ixodes frontalis
,
Haemaphysalis punctata
,
Haemaphysalis sulcata
,
Hyalomma
spp. (probably mostly
m. marginatum
),
Hyalomma aegyptium
, and
Hyalomma m. marginatum
. Many additional detaching ticks were eaten by the hosts. Uninfested bird species numbered 29 (998 individuals).
New Approach to Immunization against
Schistosoma japonicum
Authors: Li Hsü S. Y. , Hsü H. F.
Published: October 2006

Previous inoculation of rhesus monkeys with cercariae of the nonhuman strain of
Schistosoma japonicum
proved to give a rather strong protection against a subsequent challenge with its human strain.
Standard for Reporting Concentrations of Deuterium and Oxygen-18 in Natural Waters
Authors: Craig Harmon
Published: October 2006

A standard, based on the set of ocean water samples used by Epstein and Mayeda to obtain a reference standard for oxygen-18 data, but defined relative to the National Bureau of Standards isotopic reference water sample, is proposed for reporting both deuterium and oxygen-18 variations in natural waters relative to the same water. The range of absolute concentrations of both isotopes in meteoric-waters is discussed.
Drugs in the Brain
Authors: Roth Lloyd J. , Barlow Charles F.
Published: October 2006

In our studies on the entry of drugs into the central nervous system we have found the technique of autoradiography combined with radioassay to be a valuable research tool. It has disclosed such unsuspected phenomena as the dual routes of entry into the brain of acetazolamide. Although many factors controlling drug entry remain to be studied, we propose certain general conclusions.

1) The anatomical boundaries of brain are clearly reflected by the penetration and accumulation of all compounds we have studied—a finding that confirms the original proposition that whole-brain homogenates are inadequate for the study of drug and brain relationships.

2) Circulation, expressed as regional blood flow or volume of capillary blood, was seldom decisive in influencing entry or accumulation of exogenous substances in the brain. To date, the only compounds demonstrated to be circulation-dependent are trifluoroiodomethane and thiopental. Both are extremely fat-soluble. Tissue binding appears to be an additional factor in the case of thiopental.

3) Penetration is retarded by myelin. All substances we have studied have shown a relatively slower rate of entry into this tissue. In immature brain, before myelinization has taken place, the primordial white matter is readily penetrated. We have suggested that entry into mature white matter is retarded by the lamellated membranes of the myelin sheath, which should be regarded, therefore, as a component of the blood-brain barrier. The small interstitial space indicated by the limited entry of sulfate ion is an additional hindrance to dispersal of exogenous substances into brain parenchyma. The blood-brain barrier is a complex anatomical, physiological, and biochemical phenomenon, and no unitary hypothesis is adequate to embrace all the observed events.

4) Accumulation of a drug in the brain implies some form of binding or interaction between drug and tissue. Findings on injection of phenobarbital, thiopental, or diphenylhydantoin illustrate such an accumulation. These binding interactions may be nonspecific, as is probable in the case of drugs bound to plasma protein. However, a more fundamental significance is suggested when a drug is found to bind, react with, or accumulate in, a specific anatomical structure of the brain. We have made reference to this possibility in connection with the localization of isonicotinic acid hydrazide or its metabolites in the hippocampus, and we have also reported the striking accumulation of acetazolamide in hippocampus, caudate nucleus, and hypothalamus. Although the binding process is poorly understood, further investigation of these phenomena should lead to a clearer understanding of regional variations in brain chemistry. While one should not assume that the demonstration of a focal concentration of a drug implies site of action, correlation between pharmacological action, electrophysiological events, biochemical changes, and temporal and regional drug concentrations may indeed exist.
Amino Acid Composition of Some Calcified Proteins
Authors: Piez Karl A.
Published: October 2006

Amino-acid analysis shows that the proteins from two calcified tissues, enamel and snail shell, are related to collagen in that they also contain hydroxylysine. The presence of hydroxyproline is suggested but not confirmed. This evidence, together with other recent findings, suggests that hydroxylysine may have an important role in the calcification of each of these otherwise diverse proteins.
Spontaneous Ejaculation in Rat
Authors: Orbach J.
Published: October 2006

Daily seminal discharges were observed when individually caged male rats were prevented from grooming the genital region orally.
Effect of Deuteration of N—CH3Group on Potency and Enzymatic N-Demethylation of Morphine
Authors: Elison C. , Rapoport H. , Laursen R. , Elliott H. W.
Published: October 2006

Substitution of deuterium for the N-methyl hydrogens of morphine produced a significant reduction in the potency and lethality of morphine in mice regardless of the route of administration. There was no effect on the time of onset, maximal effect, or duration of action. N-demethylation by rat liver microsomal enzymes was characterized by a smaller reaction rate constant, a higher energy of activation, and a larger Michaelis constant with respect to the deuterated morphine. These findings indicated that deuteration of the N-methyl group of morphine not only caused reduction in potency, but also a reduction in the rate of oxidative N-demethylation, and a distinct weakening of the binding to the enzyme active centers.
Coesite Discoveries Establish Cryptovolcanics as Fossil Meteorite Craters
Authors: Cohen Alvin J. , Bunch Ted E. , Reid Arch. M.
Published: October 2006

Discovery of coesite in St. Peter sandstone from the central uplift of the Kentland structure, Newton County, Indiana, and in shatter cones of Lilley dolomite of Middle Silurian age from the central uplift of the Serpent Mound structure near Sinking Springs, Ohio, proves that shatter cones are evidence of meteorite impact.
Effect of Dietary Nitrate on Thyroid Function
Authors: Bloomfield Richard A. , Welsch Clifford W. , Garner George B. , Muhrer Merle E.
Published: October 2006

Experimental results indicate that 0.31 and 0.92 percent dietary nitrate, when consumed by rats and sheep respectively, can affect the normal iodine metabolism of the thyroid gland. The dietary level of iodine appears to be highly important when nitrate is present in the diet.
Identification of Small Animals by Proximity Sensing
Authors: Kavanau J. Lee
Published: October 2006

Individual deer mice are identified by magnetic proximity sensing. Approach of an animal wearing a small ferromagnetic collar unbalances an excited inductance bridge which triggers recording circuitry. In conjunction with conductance proximity sensing, the techniques can identify four individuals. Some results on the tendency of two females to follow one another are cited.
Vaccinia Dermal Infection and Methylcholanthrene in Cortisone-Treated Mice
Authors: Duran-Reynals M. L. , Stanley Barbara
Published: October 2006

Cortisone-treated mice were inoculated with vaccinia virus, and then five paintings of methylcholanthrene were applied over the site of inoculation. In 70 percent of the mice, tumors developed at the site of inoculation, and 35 percent of the mice, with and without skin tumors, also developed lymphomas. Identically treated control mice that were vacciniaimmune developed a significantly lower incidence (38 percent) of both skin tumors and lymphomas.
High Probability Opening of NMDA Receptor Channels by L-Glutamate
Authors: Jahr Craig E.
Published: October 2006

Synaptic plasticity can be triggered by calcium flux into neurons through synaptically activated
N
-methyl-D-aspartate (NMDA) receptor channels. The amplitude and time course of the resulting intracellular calcium transient depend on the number of open NMDA receptor channels and the kinetics of their activation. Short applications of L-glutamate to outside-out patches from hippocampal neurons in the presence and absence of MK-801 revealed that about 30 percent of L-glutamate-bound channels are open at the peak of the current. This high probability of opening suggests that very few channels are required to guarantee a large, localized postsynaptic calcium transient.
Balancing Selection at Allozyme Loci in Oysters: Implications from Nuclear RFLPs
Authors: Karl Stephen A. , Avise John C.
Published: October 2006

Population genetic analyses that depend on the assumption of neutrality for allozyme markers are used widely. Restriction fragment length polymorphisms in nuclear DNA of the American oyster evidence a pronounced population subdivision concordant with mitochondrial DNA. This finding contrasts with a geographic uniformity in allozyme frequencies previously thought to reflect high gene flow mediated by the pelagic gametes and larvae. The discordance likely is due to selection on protein electrophoretic characters that balances allozyme frequencies in the face of severe constraints to gene flow. These results raise a cautionary note for studies that rely on assumptions of neutrality for allozyme markers.
Collection and Washout of Airborne Pollens and Spores by Raindrops
Authors: McDonald James E.
Published: October 2006

Data on aerodynamic capture of particles are used to estimate efficiency of collection of pollen grains and spores by falling raindrops. Simple probability arguments then yield the fractional removal of airborne pollens and spores by rain. Pollen grains are generally large enough to be washed out by all but the lightest showers of large thunderstorm-type drops; smaller-sized spores experience lower removal rates. Various specialists concerned with pollen dissemination will find rain-scavenging a significant process.
Laterality of Verbal Intelligence in the Brain
Authors: Lansdell H.
Published: October 2006

Patients with left-hemisphere epilepsy and their speech mechanism abnormally located in the right cerebral hemisphere are more similar in their verbal ability to ordinary patients with right-hemisphere epilepsy than to those with left-hemisphere epilepsy.
Inhibitors of
Deuterophoma tracheiphila
in Citrus Varieties Resistant to "Mal Secco"
Authors: Aziz A. Ben , Chorin Mathilde , Monselise S. P. , Reichert I.
Published: October 2006

Growth of colonies of the fungus
Deuterophoma tracheiphila
, the causal agent of the "mal secco" disease of lemons, is inhibited by two substances, C
1
and CS
2
, which are found in resistant mandarin varieties but not in susceptible lemons and related species. Some properties of these substances are reported. CS
2
may be naringenin, but the stronger inhibitor, C
1
, has not yet been identified.
Drug Administration to Cerebral Cortex of Freely Moving Dogs
Authors: Kobayashi Tsukasa
Published: October 2006

A method is described to implant a permanent indwelling polyethylene tube venting to the surface of the cerebral cortex of the dog. Morphine, amobarbital, or imipramine was administered through the tube, and behavioral changes were observed in unanesthetized and unrestrained animals. The results are different from those occurring after intraventricular injection.
Multiple Intestinal Neoplasia Caused by a Mutation in the Murine Homolog of the APC Gene
Authors: Su Li-Kuo , Kinzler Kenneth W. , Vogelstein Bert , Preisinger Antonette C. , Moser Amy Rapaich , Luongo Cindy , Gould Karen A. , Dove William F.
Published: October 2006

Germ-line mutations of the APC gene are responsible for familial adenomatous polyposis (FAP), an autosomal dominantly inherited disease in humans. Patients with FAP develop multiple benign colorectal tumors. Recently, a mouse lineage that exhibits an autosomal dominantly inherited predisposition to multiple intestinal neoplasia (Min) was described. Linkage analysis showed that the murine homolog of the APC gene (
mApc
) was tightly linked to the
Min
locus. Sequence comparison of
mApc
between normal and Min-affected mice identified a nonsense mutation, which cosegregated with the Min phenotype. This mutation is analogous to those found in FAP kindreds and in sporadic colorectal cancers.
Involvement of the
N
-Methyl D-Aspartate (NMDA) Receptor in Synapse Elimination During Cerebellar Development
Authors: Rabacchi Sylvia , Bailly Yannick , Delhaye-Bouchaud Nicole , Mariani Jean
Published: October 2006

In many instances, the establishment of highly specific neuronal connections during development results from the rearrangement of axonal projections through the trimming of exuberant collaterals or the elimination of functional synapses or both. Although the involvement of the
N
-methyl D-aspartate (NMDA) subtype of the glutamate receptor has been demonstrated in the shaping of axonal arbors, its participation in the process of selective stabilization of synapses remains an open issue. In this study, the effects of chronic in vivo application of D,L-2-amino-5-phosphonovaleric acid (D,L-APV), a selective antagonist of the NMDA receptor, on the synapse elimination process that takes place in the developing cerebellum of the rat have been analyzed. D,L-APV treatment prevented the regression of supernumerary climbing fiber synapses in 49 percent of the recorded Purkinje cells, while the inactive isomer L-APV was ineffective. Thus, activation of the NMDA receptor is a critical step in the regression of functional synapses during development.
Dendritic Cells Exposed to Human Immunodeficiency Virus Type-1 Transmit a Vigorous Cytopathic Infection to CD4
+
T Cells
Authors: Cameron Paul U. , Freudenthal Peter S. , Barker Jeanne M. , Gezelter Stuart , Inaba Kayo , Steinman Ralph M.
Published: October 2006

The paucity of virus-laden CD4
+
cells in individuals infected with human immunodeficiency virus type-1 (HIV-1) contrasts with the greatly reduced numbers and function of these lymphocytes. A pathway is described whereby dendritic cells carry HIV-1 to uninfected T cells, amplifying the cytopathic effects of small amounts of virus. After exposure to HIV-1, dendritic cells continue to present superantigens and antigens, forming clusters with T cells that are driven to replicate. Infection of the dendritic cells cannot be detected, but the clustered T cells form syncytia, release virions, and die. Carriage of HIV-1 by dendritic cells may facilitate the lysis and loss of antigen specific CD4
+
T cells in acquired immunodeficiency syndrome.
Chromatic Response Mechanisms in the Human Fovea as Measured by Threshold Spectral Sensitivity
Authors: Sperling H. G. , Jolliffe C. L.
Published: October 2006

Threshold sensitivity was measured with 40-degree surrounds of 5.3 and 800 trolands of white, and 509, 580, and 690 mμ spectral light. With the brighter white surround there appeared peaks at 550, and 570 and a shoulder at 600 mμ. These were selectively eliminated by the spectral surrounds.
Sedimentary Rocks of the Buckeye Range, Horlick Mountains, Antarctica
Authors: Long William E.
Published: October 2006

In the Buckeye Range of the Horlick Mountains, 4000 feet of sedimentary rocks nonconformably overlie a granitic basement and underlie a thick diabasic sill. The sedimentary section consists of Devonian sandstone and shale (Horlick formation), Carboniferous (?) tillite (Buckeye formation), Permian (?) platy and carbonaceous shale (Discovery Ridge formation), and Permian arkose, shale, and numerous coal beds (Mount Glossopteris formation). This apparently is the first report of a Paleozoic tillite in Antarctica.
Separation of Cell Components in the Zonal Ultracentrifuge
Authors: Anderson N. G. , Burger C. L.
Published: October 2006

Zonal separation of particles in density gradients contained in hollow or tubeless rotors has been explored with the aim of developing a preparative counterpart of the analytical ultracentrifuge. A rotor with a capacity of 1625 milliliters has been tested up to 22,500 revolutions per minute, with sucrose density gradients used. Excellent separation of subcellular particles has been achieved as well as partial separation of the albumin and globulin peaks of serum.
Urinary Excretion of Amines in Phenylketonuria and Mongolism
Authors: Perry Thomas L.
Published: October 2006

Children with phenylketonuria excrete considerably less serotonin and tryptamine and somewhat less normetanephrine and
p
-tyramine than normal children. The excretion of these amines was not decreased in mongolism. Even during monoamine oxidase blockade,
o
-tyramine could not be detected in the urine of phenylketonurics. These findings are discussed in relation to the mental defect of phenylketonuria.
Stranded Arrangement of Sporopollenin in the Exine of Microspores of
Poa annua
Authors: Rowley John R.
Published: October 2006

In the early microspore wall of the grass
Poa annua
L., sporopollenin is arranged in bundles of anastomosing strands. Each bundle contains at least two strands, each about 50 A in diameter, which anastomose or intertwine and look like a meshwork with pores of the mesh up to 50 A in diameter. After the early microspore stage the exine becomes homogeneous; it is similar in this respect to the exines or ornamented parts of the exines of pollen of other angiosperms examined by electron microscopy.
Insulin Secretion from Pancreatic B Cells Caused by L-Arginine-Derived Nitrogen Oxides
Authors: Schmidt Harald H. H. W. , Warner Timothy D. , Ishii Kunio , Sheng Hong , Murad FeridF
Published: October 2006

L-Arginine causes insulin release from pancreatic B cells. Data from three model systems support the hypothesis that L-arginine-derived nitrogen oxides (NOs) mediate insulin release stimulated by L-arginine in the presence of D-glucose and by the hypoglycemic drug tolbutamide. The formation of NO in pancreatic B cells was detected both chemically and by the NO-induced accumulation of guanosine 3′,5′-monophosphate. N
G
-substituted L-arginine analogs inhibited the release of both insulin and NO. Protein immunoblot and histochemical analysis with antiserum to type I NO synthase suggest that the formation of NO in pancreatic B cells is catalyzed by an NADPH- (reduced form of nicotinamide adenine dinucleotide phosphate), Ca
2+
/calmodulin-dependent type I NO synthase of about 150 kilodaltons.
Crystal Structure at 3.5 Å Resolution of HIV-1 Reverse Transcriptase Complexed with an Inhibitor
Authors: Kohlstaedt L. A. , Wang J. , Friedman J. M. , Rice P. A. , Steitz T. A.
Published: October 2006

A 3.5 angstrom resolution electron density map of the HIV-1 reverse transcriptase heterodimer complexed with nevirapine, a drug with potential for treatment of AIDS, reveals an asymmetric dimer. The polymerase (pol) domain of the 66-kilodalton subunit has a large cleft analogous to that of the Klenow fragment of
Escherichia coli
DNA polymerase I. However, the 51-kilodalton subunit of identical sequence has no such cleft because the four subdomains of the pol domain occupy completely different relative positions. Two of the four pol subdomains appear to be structurally related to subdomains of the Klenow fragment, including one containing the catalytic site. The subdomain that appears likely to bind the template strand at the pol active site has a different structure in the two polymerases. Duplex A-form RNA-DNA hybrid can be model-built into the cleft that runs between the ribonuclease H and pol active sites. Nevirapine is almost completely buried in a pocket near but not overlapping with the pol active site. Residues whose mutation results in drug resistance have been approximately located.
Bone Density Measurements in vivo
Authors: Williams Dorothy E. , Mason Rossie L.
Published: October 2006

Measurements in vivo are complicated by physical and physiological problems. Lack of standard techniques between laboratories and confusion in terminology have prompted this report. The theory underlying the method is presented with data comparing values obtained by different methods.
Visual Velocity Discrimination: Effects of Spatial and Temporal Cues
Authors: Mandriota Frank J. , Mintz Donald E. , Notterman J. M.
Published: October 2006

Weber ratios were obtained for visual velocity discrimination under three topographic conditions with the same subjects and psychophysical procedures. The conditions differed regarding the presence of either temporal or spatial cues, these being correlated in magnitude with stimulus velocity. Systematic effects of the cues upon the level of velocity discrimination were noted.
Malic Dehydrogenases in Sea Urchin Eggs
Authors: Moore Richard O. , Villee Claude A.
Published: October 2006

Unfertilized
Arbacia
eggs have five electrophoretically distinct malic dehydrogenases which differ in their rates with pyridine nucleotide analogs. Both the number of peaks and their relative size change during early embryonic development. A D-malic dehydrogenase which utilizes the 3-acetylpyridine analog of DPN but not DPN itself was found. Electrophoresis on starch gel results in five peaks, all of which differ from the peaks of the L-malic dehydrogenases.
Diamonds in the Dyalpur Meteorite
Authors: Lipschutz Michael E.
Published: October 2006

Diamond was found by x-ray diffraction techniques in the Dyalpur stone; this is the fourth meteorite in which this mineral has been discovered. The diamond crystallites resemble those of Novo-Urei more than those of Goalpara.
Moon Illusion: An Observation
Authors: Goldstein Gilbert
Published: October 2006

Size comparisons of the moon are made from different locations by direct viewing (as opposed to comparisons by instrumental techniques). Under the proper conditions, the illusion is seen while the moon's position remains essentially unaltered. By this means, evidence is adduced in favor of Ptolemy's apparent-distance hypothesis.
Effects of Kinesin Mutations on Neuronal Functions
Authors: Gho M. , McDonald K. , Ganetzky B. , Saxton W. M.
Published: October 2006

Kinesin is believed to generate force for the movement of organelles in anterograde axonal transport. The identification of genes that encode kinesin-like proteins suggests that other motors may provide anterograde force instead of or in addition to kinesin. To gain insight into the specific functions of kinesin, the effects of mutations in the kinesin heavy chain gene (
khc
) on the physiology and ultrastructure of
Drosophila
larval neurons were studied. Mutations in
khc
impair both action potential propagation in axons and neurotransmitter release at nerve terminals but have no apparent effect on the concentration of synaptic vesicles in nerve terminal cytoplasm. Thus kinesin is required in vivo for normal neuronal function and may be active in the transport of ion channels and components of the synaptic release machinery to their appropriate cellular locations. Kinesin appears not to be required for the anterograde transport of synaptic vesicles or their components.
Continuously Cultured Tissue Cells and Viral Vaccines
Authors:   Committee on Tissue Culture Viruses and Vaccines
Published: October 2006

1) Continuously cultured tissue cells afford numerous potential advantages for the propagation of viruses to be used in vaccines.

2) Because continuously cultured tissue cells sooner or later become capable of growing into neoplasms when transplanted into a suitable host, every possible precaution should be taken to ensure that viral vaccines grown in cell cultures are free from living cells and cell particles larger than 0.5 to 1.0 micron.

3) The radical abnormalities that occur in cell lines derived from neoplasms and those that develop sooner or later in cell lines derived from normal tissue cannot be ignored. However, no evidence has been recorded (i) that untoward consequences follow administration of cell-free preparations from such cultures to humans or (ii) that oncogenic or other viral activity is associated with the ability of cells of these lines to grow into neoplasms when transplanted into a suitable host. It seems very unlikely, nevertheless, that acceptance could be won at present for the general use of a live-virus vaccine prepared from a virus grown in cells showing evidences of malignancy. This conclusion is based more on psychological and public relations considerations than on the available scientific information, which, however, needs considerable augmentation. In this connection, careful consideration should be given to the question whether the absence of the cited kinds of abnormalities from a continuously cultured cell system is a sufficient indicator of freedom from oncogenic potential. In the absence of unfavorable data, we judge that present knowledge does not preclude judicious extension of clinical trials, in volunteers, of appropriately filtered and otherwise controlled experimental live-virus vaccines grown in carefully selected continuously cultured cell systems. Only in this way can sufficient data be collected, and adequate criteria be developed, to define eventually the conditions for acceptability of such preparations for general administration to humans.

4) Every possible effort should be devoted to the development of non-oncogenic and otherwise acceptable cell lines from normal tissues for use in viral vaccine production. It is suggested that exploratory studies begin with continuously cultured mixed-cell populations in the diploid state and stabilized cloned cultures. Criteria for the selection and monitoring of cell lines, and progressive steps leading to large-scale application are outlined.

5) If the need for immunization against a particular viral disease should be deemed sufficiently urgent, and if no practicable alternative were available, serious consideration might be given to a vaccine prepared by inactivating the virus, grown in such a selected stabilized cell line as HeLa or human skin epithelium. The conditions of preparation would have to be such as would inactivate the most resistant known viruses and infective nucleic acids with a generous margin of safety.

6) Principal areas needing intensified research emphasis are indicated.
Spiral Flow in Rivers, Shallow Seas, Dust Devils, and Models
Authors: Tanner William F.
Published: October 2006

Spiral flow has been observed in meandering rivers, braided rivers, very shallow sea water, model experiments, and dust devils. Experimental work also produced standing spiral waves and spouts of water. Many observed spirals reversed direction from time to time. Geometry of the system, roughness, and turbulence are perhaps dominant in the control of spiral flow.
Ependymal Cilia: Distribution and Activity in the Adult Human Brain
Authors: Worthington W. Curtis , Cathcart Robert S.
Published: October 2006

Examination of 150 to 200 samples of the ependymal lining of the ventricles of nine adult human brains obtained 2½ to 6 hours post-mortem revealed cilia in at least 20 separate sites in the four ventricular cavities. In seven of the brains ciliary motion was evident, and in two of these it was widespread and rapid. It seems likely that the adult human ventricular ependyma is ciliated throughout. Currents having distinct patterns are induced in the ventricles of animal brains by ciliary motion, and such currents probably exist in man. A local mechanism for the rapid movement of cerebrospinal fluid is therefore present.
Isotopic Fractionation of Uranium in Sandstone
Authors: Rosholt John N. , Shields William R. , Garner Ernest L.
Published: October 2006

Relatively unoxidized black uranium ores from sandstone deposits in the western United States show deviations in the uranium-235 to uranium-234 ratio throughout a range from 40 percent excess uranium-234 to 40 percent deficient uranium-234 with respect to a reference uranium-235 to uranium-234 ratio. The deficient uranium-234 is leached preferentially to uranium-238 and the excess uranium-234 is believed to result from deposition of uranium-234 enriched in solutions from leached deposits.
Anoxia: Tolerance in Reptiles
Authors: Belkin Daniel A.
Published: October 2006

Measurements of the lengths of time various reptiles can continue to breathe in atmospheres of nitrogen have shown that turtles are several times more tolerant of these conditions than are other reptiles. The major correlate of this tolerance is taxonomic, rather than ecological.
Geothermal Brine Well: Mile-Deep Drill Hole May Tap Ore-Bearing Magmatic Water and Rocks Undergoing Metamorphism
Authors: White Donald E. , Anderson E. T. , Grubbs Donald K.
Published: October 2006

A deep geothermal well in California has tapped a very saline brine extraordinarily high in heavy metals and other rare elements; copper and silver are precipitated during brine production. Preliminary evidence suggests that the brine may be pure magmatic water and an active ore-forming solution. Metamorphism of relatively young rocks may also be occurring within accessible depths.
Calcium Carbonate: Factors Affecting Saturation in Ocean Waters off Bermuda
Authors: Schmalz Robert F. , Chave Keith E.
Published: October 2006

Bermuda marine waters are not in equilibrium with the bulk carbonate sediments with which they are in contact, and they are supersaturated with respect to pure calcite. This apparent supersaturation seems to result from a metastable equilibrium between sea water and the most soluble solid phase available locally in excess.
Loss of Radioactivity from Labeled DNA of Primary Human Amnion Cells
Authors: Chang R. Shihman , Vetrovs Helen
Published: October 2006

Primary human amnion cultures labeled with glycine-2-C
14
or thymidine-2-C
14
released more radioactivity into the media than could be accounted for by cell replacement. This is interpreted as degradation of acid-insoluble polydeoxynucleotides in a living human cell.
Strontium-90 Content of Deciduous Human Incisors
Authors: Rosenthal Harold L. , Gilster John E. , Bird John T.
Published: October 2006

The concentrations of strontium-90 in deciduous incisor teeth of children born in St. Louis between 1949 to 1957 are in accord with estimated bone levels, suggesting that human deciduous teeth are useful as an index of strontium-90 accumulation during the time the teeth are formed.
Spermatogenesis in Man: An Estimate of Its Duration
Authors: Heller Carl G. , Clermont Yves
Published: October 2006

Testicular biopsies were obtained at various intervals after intratesticular injections of tritiated thymidine. Radioautographs revealed that the most mature labeled germ cells were the preleptotene spermatocytes at 1 hour, the midpachytene spermatocytes at 16 days, and the immature spermatids at 32 days after injection. These results indicated that one cycle of the seminiferous epithelium lasts 16 days, and the whole of spermatogenesis is estimated to consume approximately 64 days.
Germination of
Melampyrum lineare
: Interrelated Effects of Afterripening and Gibberellic Acid
Authors: Curtis E. J. C. , Cantlon J. E.
Published: October 2006

Seed germination of
Melampyrum lineare
proceeds only after activation followed by an extended period of chilling. Up to one-third of seeds can be activated by storage at room temperature, while all seeds are activated if treated with gibberellic acid. Chilling before activation is ineffective.
Semiconducting Region of Ytterbium
Authors: Souers P. C. , Jura G.
Published: October 2006

The resistivity of elemental ytterbium at room temperature rises, by a factor of 11, to a maximum at a pressure of 40 kilobars; a further increase in pressure causes a polymorphic transition; the new phase has a resistivity 80 percent of that of the metal at 1 atmosphere. In the temperature-pressure diagram, the phase boundary has a negative slope. The phase boundary, determined from -190° to 360°C, is a straight line that may be extrapolated nearly to the known α-β transition at 1 atmosphere. Between the transition pressure and 20 kbar, the lowest pressure at which the measurements were made, ytterbium behaved as a semiconductor. The temperature coefficient of resistance is negative; at constant pressure, the resistivity shows the exponential temperature dependence characteristic of a semiconductor. The parameter in the exponential would correspond to an energy gap 0.015 ev at 20 kbar, an increase with pressure to a maximum of 0.080 ev at 37 kbar, and then a decrease to 0.05 ev at 45 kbar.
Amino Acid Composition of Univalent Fragments of Rabbit Antibody
Authors: Mandy William J. , Stambaugh Mary K. , Nisonoff Alfred
Published: October 2006

Univalent fragments of γ-globulin preparations from four individual rabbits were fractionated and the amino acid compositions of end fractions were compared. For amino acids with uncharged side chains, differences were consistently less than one residue per fragment of molecular weight 50,000. There were differences in the content of amino acids, other than glutamic acid, with charged side chains; these were in the direction expected on the basis of relative strength of adherence to carboxymethyl cellulose and electrophoretic mobility. Exclusive of any possible differences in amide, the total difference in charged groups was three to four residues per fragment. Since the net charge of univalent fragments reflects that of the γ-globulin molecule from which the fragments are derived, corresponding differences in composition may also exist among whole γ-globulin molecules.
Muscle-Equivalent Environmental Radiation Meter of Extreme Sensitivity
Authors: Kastner Jacob , Rose John E. , Shonka Francis R.
Published: October 2006

A 16.5 liter spherical ion chamber was constructed of conducting muscle-equivalent plastic and filled to 760 mm-Hg with a muscle-equivalent gas. The use of the chamber for measurements of natural environmental backgrounds was made quite feasible with the aid of the recently developed Shonka vibrating quartz fiber electrometer. This instrument is routinely operable at the extremely high sensitivity of better than 5000 divisions per volt. This system, therefore, has made possible reproducible measurements of absorbed dose-rates of fractions of a micro-rad per hour without any need for the usual corrections for wall-effect, stopping power, and so forth.
Planets and Comets: Role of Crystal Growth in Their Formation
Authors: Donn Bertram , Sears Gerald W.
Published: October 2006

The application of crystal growth theory to the formation of smoke particles from the primordial solar nebula indicates that solid particles with filamentary structures would form. Such particles would facilitate successive aggregation into planets, comets, and asteroids. The difficulties associated with the aggregation of spherical smoke particles would thus be avoided.
"Pliocene-Pleistocene" Boundary in Deep-Sea Sediments
Authors: Riedel W. R. , Bramlette M. N. , Parker F. L.
Published: October 2006

Changes in planktonic microfossil assemblages in Atlantic sediment cores, at approximately the beginning of the Quaternary, correspond in a general way with those recognized in Pacific cores. How closely the horizon marked by these changes approximates to the Pliocene-Pleistocene boundary is not yet established.
Poliomyelitis in Monkeys: Decreased Susceptibility after Avoidance Stress
Authors: Marsh James T. , Lavender John F. , Chang Shueh-Shen , Rasmussen A. F.
Published: October 2006

Eleven monkeys were subjected to avoidance stress for 24 hours followed immediately by intravenous inoculation with type I poliovirus. Twelve control monkeys not so stressed were similarly inoculated. Seven of 11 stressed animals survived the infection while only one of the controls lived and their average incubation period was significantly longer than the average for controls. The number of circulating lymphocytes decreased significantly in experimental animals during and immediately after exposure to stress.
Control and Training of Individual Motor Units
Authors: Basmajian J. V.
Published: October 2006

Experiments clearly demonstrate that with the help of auditory and visual cues man can single out motor units and control their isolated contractions. Experiments on the training of this control, interpreted as the training of descending pathways to single anterior horn cells, provide a new glimpse of the fineness of conscious motor controls. After training, subjects can recall into activity different single motor units by an effort of will while inhibiting the activity of neighbors. Some learn such exquisite control that they soon can produce rhythms of contraction in one unit, imitating drum rolls, etc. The quality of control over individual anterior horn cells may determine rates of learning.
Daily Rhythm of Luciferin Activity in
Gonyaulax polyedra
Authors: Bode Vernon C. , DeSa Richard , Hastings J. Woodland
Published: October 2006

Extracts prepared from
Gonyaulax
cells harvested late in the 12-hour dark period of an artificial 24-hour day contain as much as four times more luciferin activity than similar extracts prepared during the light period. If cultures are not treated with heat or light to reduce the flashing associated with handling, the time of maximum activity is obscured.
Circulating Interferon in Mice after Intravenous Injection of Virus
Authors: Baron Samuel , Buckler Charles E.
Published: October 2006

Circulating interferon was detectable in mouse serum within 1 hour after the intravenous injection of various types of virus and it reached maximum levels in about 4 hours. Rapidly produced interferon may play a role in the pathogenesis of viral infection and in viral interference.
DNA Sequences from a Fossil Termite in Oligo-Miocene Amber and their Phylogenetic Implications
Authors: DeSalle Rob , Gatesy John , Wheeler Ward , Grimaldi David
Published: October 2006

DNA was extracted from the fossil termite
Mastotermes electrodominicus
preserved in Oligo-Miocene amber (25 million to 30 million years old). Fragments of mitochondrial [16
S
ribosomal DNA (rDNA)] and nuclear (18
S
rDNA) genes were amplified by polymerase chain reaction. Phylogenetic analysis of fossil and extant 18
S
rDNA confirmed morphological cladistic analyses of living dictyopterans (termites, cockroaches, and mantids). The fossil termite shares several sequence attributes with
Mastotermes darwiniensis
. Addition of this fossil to living-species phylogeny is required to substantiate
Mastotermes
monophyly and affects molecular phylogenetic hypotheses of termites in this, the oldest DNA yet characterized.
Actin Filament Dynamics in Living Glial Cells Imaged by Atomic Force Microscopy
Authors: Henderson E. , Haydon P. G. , Sakaguchi D. S.
Published: October 2006

Observation of filamentous actin (F-actin) in living cells is currently limited to the resolution of the light microscope. Higher resolution procedures require sample fixation and preclude dynamic studies. The atomic force microscope (AFM) can image and manipulate samples at very high, sometimes atomic resolution by scanning a fine tip over the surface of interest and detecting physical interactions between the tip and sample. This study demonstrates that F-actin can be readily resolved in living cells with the AFM and that the dynamic properties of F-actin are easily observed.