bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipoprotein Mutations in Pigs Are Associated with Elevated Plasma Cholesterol and Atherosclerosis
Authors: Rapacz Jan , Hasler-Rapacz Judith , Taylor Katherine M. , Checovich William J. , Attie Alan D.
Published: October 2006

A strain of pigs bearing three immunogenetically defined lipoprotein-associated markers (allotypes), designated Lpb5, Lpr1, and Lpu1, has marked hypercholesterolemia on a low fat, cholesterol-free diet. Unlike individuals with familial hypercholesterolemia or WHHL rabbits, the affected pigs have normal low density lipoprotein receptor activity. The animals, by 7 months of age, have extensive atherosclerotic lesions in all three coronary arteries. This strain of pig represents an animal model for atherosclerosis and hypercholesterolemia associated with mutations affecting the structures of plasma lipoproteins. One of the variant apolipoproteins, Lpb5, is apolipoprotein-B. A second variant apolipoprotein (Lpr1), termed apo-R, is a 23-kilodalton protein present in both the very low density (
d
< 1.006 g/ml) and the very high density (
d
> 1.21 g/ml) fractions of pig plasma. Isoforms of this protein correlate with two
Lpr
alleles,
Lpr
1
and
Lpr
2
. The
Lpr
genes segregate independently of the
Lpb
5
and
Lpu
1
alleles. The Lpu1 allotype is a component of low density lipoprotein and is genetically linked to
Lpb
5
.
Plasmodium falciparum
Malaria: Band 3 as a Possible Receptor During Invasion of Human Erythrocytes
Authors: Okoye Vincent C. N. , Bennett Vann
Published: October 2006

Human erythrocyte band 3, a major membrane-spanning protein, was purified and incorporated into liposomes. These liposomes, at nanomolar concentrations of protein, inhibited invasion of human erythrocytes in vitro by the malaria parasite
Plasmodium falciparum
. Liposomes containing human band 3 were ten times more effective in inhibiting invasion than those with pig band 3 and six times more effective than liposomes containing human erythrocyte glycophorin. Liposomes alone or liposomes containing erythrocyte glycolipids did not inhibit invasion. These results suggest that band 3 participates in the invasion process in a step involving a specific, high-affinity interaction between band 3 and some component of the parasite.
Mammalian and Yeast
ras
Gene Products: Biological Function in Their Heterologous Systems
Authors: DeFeo-Jones Deborah , Tatchell Kelly , Robinson Lucy C. , Sigal Irving S. , Vass William C. , Lowy Douglas R. , Scolnick Edward M.
Published: October 2006

Activated versions of
ras
genes have been found in various types of malignant tumors. The normal versions of these genes are found in organisms as diverse as mammals and yeasts. Yeast cells that lack their functional
ras
genes, RAS
SC
-1 and RAS
SC
-2, are ordinarily nonviable. They have now been shown to remain viable if they carry a mammalian
ras
H
gene. In addition, yeast-mammalian hybrid genes and a deletion mutant yeast RAS
SC
-1 gene were shown to induce morphologic transformation of mouse NIH 3T3 cells when the genes had a point mutation analogous to one that increases the transforming activity of mammalian
ras
genes. The results establish the functional relevance of the yeast system to the genetics and biochemistry of cellular transformation induced by mammalian
ras
genes.
Erythrosin B Inhibition of Neurotransmitter Accumulation by Rat Brain Homogenate
Authors: Logan William J. , Swanson James M.
Published: October 2006

A mixture of seven food dyes inhibited the accumulation of eight neurotransmitters or neurotransmitter precursors by rat brain homogenate. At a low concentration (1 microgram per milliliter), erythrosin B (FD&C red 3) was the only dye that inhibited dopamine accumulation. Erythrosin also was effective in decreasing the accumulation of all the other transmitter substances, suggesting that the inhibition is nonspecific and probably secondary to general membrane alteration.
A Single Recombinant Plasmid Expressing Two Major Outer Surface Proteins of the Lyme Disease Spirochete
Authors: Howe Timothy R. , Mayer Leonard W. , Barbour Alan G.
Published: October 2006

A gene bank of DNA from the Lyme disease spirochete was constructed in the plasmid pBR322. Plasmid pTRH32, a recombinant that in
Escherichia coli
expresses the two major outer surface proteins of the Lyme disease spirochete, was identified. One of the recombinant products, designated OspA, represents a surface protein that appears to be common to all Lyme disease spirochetes, whereas the other recombinant product, designated OspB, represents a more variable surface protein. This recombinant plasmid provides a foundation for future studies on the epidemiology and pathogenesis of Lyme disease as well as on the genetic organization of the etiologic agent.
Reversal of Oncogenesis by the Expression of a Major Histocompatibility Complex Class I Gene
Authors: Tanaka Kenichi , Isselbacher Kurt J. , Khoury George , Jay Gilbert
Published: October 2006

The classical transplantation antigens (the major histocompatibility complex class I antigens) play a key role in host defense against cells expressing foreign antigens. Several naturally occurring tumors and virally transformed cells show an overall suppression of these surface antigens. Since the class I molecules are required in the presentation of neoantigens on tumor cells to the cytotoxic T lymphocytes, their absence from the cell surface may lead to the escape of these tumors from immunosurveillance. To test this possibility, a functional class I gene was transfected into human adenovirus 12-transformed mouse cells that do not express detectable levels of class I antigens; the transformants were tested for expression of the transfected gene and for changes in oncogenicity. The expression of a single class I gene, introduced by DNA-mediated gene transfer into highly tumorigenic adenovirus 12-transformed cells, was sufficient to abrogate the oncogenicity of these cells. This finding has important implications for the regulation of the malignant phenotype in certain tumors and for the potential modulation of oncogenicity through derepression of the endogenous class I genes.
Regenerating Fish Optic Nerves and a Regeneration-Like Response in Injured Optic Nerves of Adult Rabbits
Authors: Schwartz M. , Belkin M. , Harel A. , Solomon A. , Lavie V. , Hadani M. , Rachailovich I. , Stein-Izsak C.
Published: October 2006

Regeneration of fish optic nerve (representing regenerative central nervous system) was accompanied by increased activity of regeneration-triggering factors produced by nonneuronal cells. A graft of regenerating fish optic nerve, or a "wrap-around" implant containing medium conditioned by it, induced a response associated with regeneration in injured optic nerves of adult rabbits (representing a nonregenerative central nervous system). This response was manifested by an increase of general protein synthesis and of selective polypeptides in the retinas and by the ability of the retina to sprout in culture.
Localized Control of Ligand Binding in Hemoglobin: Effect of Tertiary Structure on Picosecond Geminate Recombination
Authors: Friedman J. M. , Scott T. W. , Fisanick G. J. , Simon S. R. , Findsen E. W. , Ondrias M. R. , MacDonald V. W.
Published: October 2006

The picosecond geminate rebinding of molecular oxygen was monitored in a variety of different human, reptilian, and fish hemoglobins. The fast (100 to 200 picoseconds) component of the rebinding is highly sensitive to protein structure. Both proximal and distal perturbations of the heme affect this rebinding process. The rebinding yield for the fast process correlates with the frequency of the stretching motion of the iron-proximal histidine mode (ν
Fe-His
) observed in the transient Raman spectra of photodissociated ligated hemoglobins. The high-affinity R-state species exhibit the highest values for ν
Fe-His
and the highest yields for fast rebinding, whereas low affinity R-state species and T-state species exhibit lower values of ν
Fe-His
and correspondingly reduced yields for this geminate process. These findings link protein control of ligand binding with events at the heme.
Growth Regulation of Human Melanocytes: Mitogenic Factors in Extracts of Melanoma, Astrocytoma, and Fibroblast Cell Lines
Authors: Eisinger Magdalena , Marko Olga , Ogata Shun-Ichiro , Old Lloyd. J.
Published: October 2006

Melanocytes derived from fetal or adult skin do not propagate in vitro unless cultured in the presence of factors such as 12-
O
-tetradecanoylphorbol 13-acetate (TPA). In a search for physiological factors regulating the growth of melanocytes, extracts of various cultured cell types were tested. Factors produced by melanoma and astrocytoma cell lines support continued proliferation of melanocytes in the absence of TPA. WI-38, a fibroblast cell line derived from human embryonic lung, was the most active source of melanocyte growth factors. No melanocyte growth-promoting activity was found in extracts of cultured neuroblastoma, renal cancer, normal keratinocytes, or renal epithelium. Nerve growth factor, epidermal growth factor, melanocyte-stimulating hormone, transforming growth factor-β, and platelet-derived growth factor did not have growth-promoting activity for melanocytes. The presence of melanocyte growth factors and TPA together resulted in the strongest mitogenic activity for melanocytes, permitting the recovery (at 20 days) of 4 to 20 times as many cells as in growth factor or TPA alone.
Stereoscopic Images in Confocal (Tandem Scanning) Microscopy
Authors: Boyde Alan
Published: October 2006

Stereoscopic pair images with parallel projection geometry are obtained by through-focusing along two inclined axes while recording two (summed and stacked) images with a microscope with a very shallow depth of field. The two stack images sample the same depth slice of translucent or reflective specimens. The method will work most conveniently with a tandem scanning microscope (a direct-view, confocal scanning optical microscope). This is a direct method for recording stereo images that can be used to the limit of resolution in optical microscopy. It demonstrates a previously unrealized advantage of confocal optical microscopy.
Timers in Developing Systems
Authors: Soll David R.
Published: October 2006

Conditional methods are proposed for investigating the number and relationships of processes that are rate-limiting for the genesis of consecutive stages in a developmental sequence. These methods depend on the differential sensitivity of "timer" pathways to small changes in temperature and can be applied to any developmental sequence in which discrete stages can be reproducibly monitored with time. We have applied the methods to multicellular morphogenesis in the slime mold
Dictyostelium discoideum
and have obtained an unexpected tentative scheme for timer relationships. A minimum of six timers has been delineated, each specific for at least one morphological stage. The majority of these timers appear to be in parallel.
DNA Repair and Longevity Assurance in
Paramecium tetraurelia
Authors: Smith-Sonneborn Joan
Published: October 2006

At given doses and clonal ages, ultraviolet irradiation-induced DNA damage reduced clonal life-span, but when followed by photoreactivation, extension of clonal life-span was observed. If photoreactivation preceded the ultraviolet treatment, no significant beneficial effect was detected. Because studies of others have shown that photoreactivation repair monomerizes the ultraviolet-induced cyclobutane dimers in DNA, but does not affect the other photoproducts, these results indicate that DNA damage can influence the duration of clonal life-span unless that damage is repaired. Repeated treatment with ultraviolet and photoreactivation resulted in significant mean and maximal clonal life-span extension when compared with untreated controls, and it is assumed that the rejuvenation effect was due to the correction or prevention of some age damage.
A Test of Some Models of Hemispheric Speech Organization in the Left- and Right-Handed
Authors: Satz Paul
Published: October 2006

A new method generates specific predictions concerning the expected frequencies of aphasia after unilateral injury to the brain in the left- and right-handed. These predictions are then compared with the observed data for all known studies between 1935 and 1973 to derive the best-fitting model of hemispheric speech lateralization in the left- and right-handed.
Discrimination Learning Without Short-Term Memory: Dissociation of Memory Processes in Pigeons
Authors: Maki William S.
Published: October 2006

Pigeons were trained to perform delayed matching to samples of food and no food when each sample concurrently served as the outcome of a discrimination learning trial which immediately preceded each matching trial. Ambient light presented during the delays after the samples of food or no food severely disrupted matching but had no effect on the rate of discrimination learning.
Development of the Rat's Uncrossed Retinotectal Pathway and Its Relation to Plasticity Studies
Authors: Land P. W. , Lund R. D.
Published: October 2006

In the normal newborn rat the retinotectal pathway from each eye distributes across the whole area of both the ipsilateral and contralateral superior colliculus. Most of the ipsilateral projection retracts during the first ten postnatal days to produce the normal adult pattern, but retraction fails to occur if one eye is removed at birth.
Müllerian Duct Regression in the Embryo Correlated with Cytotoxic Activity Against Human Ovarian Cancer
Authors: Donahoe Patricia K. , Swann David A. , Hayashi Akira , Sullivan Marcia D.
Published: October 2006

A significant cytotoxicity index was obtained when human ovarian cancer cells in a microcytotoxicity assay were exposed during the S (DNA-synthesizing) phase of the cell cycle to purified fractions of testis exhibiting high Müllerian inhibiting substance bioactivity. The same effect was not observed when these fractions were tested against human glioblastoma or fibroblast lines. Most human ovarian cancers are said to resemble Müllerian tissues histologically. Müllerian inhibiting substance may thus deserve further study as a potential chemotherapeutic agent.
Receptor-Mediated Internalization of Fluorescent Chemotactic Peptide by Human Neutrophils
Authors: Niedel James E. , Kahane Itzhak , Cuatrecasas Pedro
Published: October 2006

Tetramethylrhodamine labeled
N
-formyl-Nle-Leu-Phe-Nle-Tyr-Lys is a potent chemoattractant for human neutrophils. Binding of this peptide to living neutrophils was observed by means of video intensification microscopy. At 37°C, diffuse membrane fluorescence was seen initially, followed by rapid aggregation and internalization of the fluorescent peptide. These processes are dependent on specific binding to the formyl peptide chemotactic receptor.
Generation of Unidirectionally Propagated Action Potentials in a Peripheral Nerve by Brief Stimuli
Authors: van den Honert Christopher , Mortimer J. Thomas
Published: October 2006

Single, unidirectionally propagated action potentials can be elicited in peripheral nerves by electrical stimuli of short duration. Propagation in one direction is blocked anodically by means of a quasi-trapezoidal stimulus wave form and a modified tripolar electrode configuration. Propagation in the other direction proceeds unhindered. This technique may be applicable to collision blocking of motor nerves for neural prostheses.
Limbic System Interrelations: Functional Division Among Hippocampal-Septal Connections
Authors: Berger Theodore W. , Thompson Richard F.
Published: October 2006

Neuronal activity was recorded simultaneously from hippocampus and medical or lateral septum during classical conditioning of the rabbit nictitating membrane response. Although similarities exist between hippocampal and lateral septal patterns of activity, medial septal unit discharges indicate a different role during learning.
Homology of Genome of AIDS-Associated Virus with Genomes of Human T-Cell Leukemia Viruses
Authors: Arya Suresh K. , Gallo Robert C. , Hahn Beatrice H. , Shaw George M. , Popovic Mikulas , Salahuddin S. Zaki , Wong-Staal Flossie
Published: October 2006

A T lymphotropic virus found in patients with the acquired immune deficiency syndrome (AIDS) or lymphadenopathy syndrome has been postulated to be the cause of AIDS. Immunological analysis of this retrovirus and its biological properties suggest that it is a member of the family of human T-lymphotropic retroviruses known as HTLV. Accordingly, it has been named HTLV-III. In the present report it is shown by nucleic acid hybridization that sequences of the genome of HTLV-III are homologous to the structural genes (
gag
,
pol
, and
env
) of both HTLV-I and HTLV-II and to a potential coding region called pX located between the
env
gene and the long terminal repeating sequence that is unique to the HTLV family of retroviruses.
Serotonin Selectively Inhibits Growth Cone Motility and Synaptogenesis of Specific Identified Neurons
Authors: Haydon P. G. , McCobb D. P. , Kater S. B.
Published: October 2006

The motile activity of growth cones of specific identified neurons is inhibited by the neurotransmitter serotonin, although other identified neurons are unaffected. As a consequence, affected neurons are unable to form electrical synapses, whereas other neurons whose growth is unaffected can still interconnect. This result demonstrates that neurotransmitters can play a prominent role in regulating neuronal architecture and connectivity in addition to their classical role in neurotransmission.
Phospholipid Methylation and Biological Signal Transmission
Authors: Hirata Fusao , Axelrod Julius
Published: October 2006

Many types of cells methylate phospholipids using two methyltransferase enzymes that are asymmetrically distributed in membranes. As the phospholipids are successively methylated, they are translocated from the inside to the outside of the membrane. When catecholamine neurotransmitters, lectins, immunoglobulins or chemotaxic peptides bind to the cell surface, they stimulate the methyltransferase enzymes and reduce membrane viscosity. The methylation of phospholipids is coupled to Ca
2+
influx and the release of arachidonic acid, lysophosphatidylcholine, and prostaglandins. These closely associated biochemical changes facilitate the transmission of many signals through membranes, resulting in the generation of adenosine 3′,5′-monophosphate in many cell types, release of histamine in mast cells and basophils, mitogenesis in lymphocytes, and chemotaxis in neutrophils.
Expression of Streptococcal M Protein in
Escherichia coli
Authors: Scott June R. , Fischetti Vincent A.
Published: October 2006

The structural gene for group A streptococcal M protein, the fibrillar surface molecule enabling the organism to resist phagocytosis, has been cloned into
Escherichia coli
. The molecule produced by
Escherichia coli
is slightly larger than the M protein isolated by solubilization of the streptococcal cell wall, but is similar in size to that secreted by streptococcal protoplast and L forms. Immunologically, the molecule synthesized by
Escherichia coli
has the same type-specific determinants as the streptococcal M protein.
Costae of
Tritrichomonas foetus
: Purification and Chemical Composition
Authors: Sledge W. E. , Larson A. D. , Hart L. T.
Published: October 2006

The costa is an intracellular organelle common to all trichomonads. Costae from
Tritrichomonas foetus
have been purified by a method which involves lysis of
T. foetus
with the heat-stable hemolysin produced by
Pseudomonas aeruginosa
, followed by differential centrifugation. Analysis of the purified costae demonstrated that the organelle is composed of 95 percent carbohydrate and 5 percent protein. The carbohydrate moiety, probably a polysaccharide, consisted of glucose (95 percent), mannose (0.4 percent), glucosamine (1.4 percent), ribose (0.6 percent), and an unidentified sugar (2.6 percent). The kinetosomal complex was attached to the costa after initial lysis of cells but was separated from the costa during purification.
Eyes Transplanted to Tadpole Tails Send Axons Rostrally in Two Spinal-Cord Tracts
Authors: Katz Michael J. , Lasek Raymond J.
Published: October 2006

Axons from eyes transplanted to the tail in
Xenopus
larvae enter the caudal spinal cord and follow two adjacent tracts rostrally to the level of the cerebellum. When eyes are transplanted to the ear area, optic axons enter the hindbrain and follow the same tracts rostrally and caudally. These sensory pathways normally contain the embryonic sensory system of the Rohon-Beard axons and the descending and ascending tracts of nerve V. We propose that the transplanted optic axons have followed a continuous substrate sensory pathway normally shared by a number of different sensory tracts.
The Origins of Gene Instability in Yeast
Authors: Roeder G. Shirleen , Farabaugh Philip J. , Chaleff Deborah T. , Fink Gerald R.
Published: October 2006

Two unstable mutations at the
his
4 locus of yeast are due to the insertion of the transposable elements
Ty
912 and
Ty
917 into the
his
4 regulatory region. The two transposons are related, one being derived from the other by a substitution of 4000 base pairs of DNA. Element
Ty
912 includes identical terminal repeats, whereas the terminal repeats of
Ty
917 are not identical. Transposition of
Ty
912 or
Ty
917 generates 5-base-pair duplications of the target DNA at either end of the element. Expression and reversion of a
his
4 gene containing
Ty
912 or
Ty
917 is controlled by three unlinked regulatory genes. The properties of these regulatory genes are similar to those described for the controlling elements in maize.
Isolation of Mutants of an Animal Virus in Bacteria
Authors: Peden K. W. C. , Pipas J. M. , Pearson-White S. , Nathans D.
Published: October 2006

Mutants of animal viruses can be isolated in bacteria by recombinant DNA methods. Since no viral functions are required for propagation of recombinants in bacteria, viral mutants with lethal changes in
cis
- or
trans
-acting elements can be isolated, as well as partially or conditionally defective mutants. In the case of viruses with small DNA genomes, such as the tumorigenic simian virus 40 (SV40), the entire viral DNA can be inserted into the bacterial plasmid pBR322 and cloned in
Escherichia coli
. Recombinant plasmids with a single copy of SV40 DNA cause morphological transformation of mouse cells in culture with the same efficiency as SV40 DNA isolated from virus-infected monkey cells, but the recombinant DNA is noninfectious and replicates poorly in permissive cells. However, SV40 DNA excised from the plasmid replicates as well as authentic viral DNA and is fully infectious. SV40 mutants with small deletions or base substitutions have been isolated by in vitro site-specific or random local mutagenesis of recombinant DNA followed by cloning in
E. coli
. Many of the mutants thus isolated are defective in specific viral functions.
Electrochemical Reduction of Horse Heart Ferricytochrome C at Chemically Derivatized Electrodes
Authors: Lewis Nathan S. , Wrighton Mark S.
Published: October 2006

Platinum or gold electrodes derivatized with an
N
,
N
′-dialkyl-4,4′-bipyridinium reagent can be used to reduce horse heart ferricytochrome c, whereas reduction does not occur at the "naked" electrodes. From 3 to 17.7 millimoles per liter, the reduction of ferricytochrome c is mass transport-limited at electrode potentials more negative than about -0.6 volt against a saturated calomel reference electrode. Data for the photoreduction of ferricytochrome c at derivatized p-type silicon photocathodes show directly that the rate of reduction is mass transport-limited. Use of derivatized electrodes may allow convenient manipulation and analysis of biological molecules that do not ordinarily respond at conventional electrodes.
Autoradiographic Evidence for a Calcitonin Receptor on Testicular Leydig Cells
Authors: Chausmer Arthur B. , Stevens Michael D. , Severn Charles
Published: October 2006

Previous studies have indicated that there is a relation between testicular function and adequate concentrations of zinc in testicular cells, and that calcitonin alters cellular zinc transfer in the testis. The present studies provide autoradiographic evidence that calcitonin binds in vivo to the cell membrane of testicular Leydig cells. The data thus confirm the presence of the testicular cell membrane calcitonin receptors that were previously demonstrated indirectly by Scatchard analysis of data collected from binding studies.
Indoor Airborne Asbestos Pollution: from the Ceiling and the Floor
Authors: Sebastien P. , Bignon J. , Martin M.
Published: October 2006

Electron microscopic measurements of the concentrations of airborne asbestos were carried out inside and outside an office building having ceilings sprayed with a crocidolite-containing material and floors covered with vinyl-chrysotile tiles. Under normal conditions in this building, constructed 10 years ago, the two asbestos-containing materials released fibers into the air. This is the first measurement of elevated (up to 170 nanograms per cubic meter) concentrations of indoor airborne asbestos associated with the weathering of asbestos floor tiles during their service life. Asbestos flooring is used in a large number of buildings and represents the third largest use of asbestos fibers in the United States and in Europe, ranking after roofing and asbestos-cement pipe.
Active Genes Are Sensitive to Deoxyribonuclease I During Metaphase
Authors: Gazit Bruria , Cedar Howard , Lerer Israela , Voss Ruth
Published: October 2006

The active exogenous murine leukemia virus sequences of mouse cells growing in culture are preferentially digested by deoxyribonuclease I in metaphase chromosomes. As determined by nuclear nick translation, all of the gene sequences of these cells active during interphase are in a deoxyribonuclease I-sensitive conformation during metaphase. This method of nick translation can therefore be used to label chromosomes in situ in order to visualize the active regions of the genome.
Isolation of St. Louis Encephalitis Virus from Overwintering
Culex pipiens
Mosquitoes
Authors: Bailey Charles L. , Eldridge Bruce F. , Hayes David E. , Watts Douglas M. , Tammariello Ralph F. , Dalrymple Joel M.
Published: October 2006

Two strains of St. Louis encephalitis virus were isolated from overwintering mosquitoes collected in Maryland and Pennsylvania during January and February 1977. These isolations from
Culex pipiens
constitute evidence that a mosquito-borne flavivirus can persist in a vector mosquito in temperate climates during the winter season.
Expression of a Platelet-Derived Growth Factor-Like Protein in Simian Sarcoma Virus Transformed Cells
Authors: Deuel Thomas F. , Huang Jung San , Huang Shuan Shian , Stroobant Paul , Waterfield Michael D.
Published: October 2006

The near identity of the partial amino acid sequence of human platelet-derived growth factor (PDGF) and that predicted for p28
sis
, the putative transforming protein of the simian sarcoma virus (SSV), suggests expression of a growth factor activity may be central for transformation by SSV. It is now reported that SSV-transformed cells but not control cells contain a growth factor activity that is identical to PDGF in immunoassay, in mitogenic dose response, and in specific mitogenic activity. The protein immunoprecipitated by antiserum to human PDGF has an apparent molecular weight of 20,000, identical to that of p20
sis
, the putative intracellular degradation product of p28
sis
. The results support the concept that expression of a PDGF-like molecule, which appears to be the product of the viral-
sis
gene, is responsible for the abnormal regulation of growth is SSV-transformed cells.
Productive Infection and Cell-Free Transmission of Human T-Cell Leukemia Virus in a Nonlymphoid Cell Line
Authors: Clapham P. , Nagy K. , Cheingsong-Popov R. , Exley M. , Weiss R. A.
Published: October 2006

Human T-cell leukemia virus (HTLV), American PL isolate, was transmitted by cocultivation and by cell-free filtrates to a nonlymphoid human osteogenic sarcoma (HOS) cell line, designated HOS/PL, but not to nine other lines bearing receptors for HTLV. HOS and HOS/PL cells are not dependent on interleukin-2 and do not express interleukin-2 receptors that are recognized by anti-Tac monoclonal antibody. HTLV released by the Japanese MT2 cell line was also transmitted to HOS cells. The infected HOS cells release substantial titers of progeny HTLV which is antigenically indistinguishable from parental virus and is able to transform T cells.
Inhibition of Human Acute Lymphoblastic Leukemia Cells by Immunotoxins: Potentiation by Chloroquine
Authors: Ramakrishnan S. , Houston L. L.
Published: October 2006

Immunotoxins containing pokeweed antiviral protein and monoclonal antibodies against human T cells or human transferrin receptor efficiently killed acute lymphoblastic leukemia cells. Chloroquine specifically enhanced the rate of protein synthesis inhibition by immunotoxin. Depending on its concentration, chloroquine (10 to 100 micromolar) reduced by up to 65-fold the amount of immunotoxin required to inhibit protein synthesis in the target cells 50 percent.
Gene Product of v-
fgr
onc
: Hybrid Protein Containing a Portion of Actin and a Tyrosine-Specific Protein Kinase
Authors: Naharro German , Robbins Keith C. , Reddy E. Premkumar
Published: October 2006

The nucleotide sequence of the region of Gardner-Rasheed feline sarcoma virus (GR-FeSV) encoding its primary translation product, p70
gag-fgr
, has been determined. From the nucleotide sequence, the amino acid sequence of this transforming protein was deduced. Computer analysis indicates that a portion of p70
gag-fgr
has extensive amino acid sequence homology with actin, a eukaryotic cytoskeletal protein. A second region of p70
gag-fgr
is closely related to the tyrosine-specific kinase gene family. Thus, the v-
fgr
oncogene appears to have arisen as a result of recombinational events involving two distinct cellular genes, one coding for a structural protein and the other for a protein kinase.
Human-Proto-Oncogene Nucleotide Sequences Corresponding to the Transforming Region of Simian Sarcoma Virus
Authors: Josephs Steven F. , Guo Chan , Ratner Lee , Wong-Staal Flossie
Published: October 2006

The nucleotide sequences of the six regions within the normal human cellular locus (c-
sis
) that correspond to the entire transforming region of the simian sarcoma virus (SSV) genome (v-
sis
) were determined. The regions are bounded by acceptor and donor splice sites and, except for region 6, resemble exons. Region 6 lacks a 3′ donor splice site and terminates -5 base pairs from the 3′ v-
sis
-helper-viral junction. This is consistent with a model proposing that SSV was generated by recombination between proviral DNA of simian sarcoma associated virus and proto-
sis
and that introns were spliced out subsequently from a fused viral-
sis
messenger RNA. This also suggests that the 3′ recombination occurred within an exon of the woolly monkey (
Lagothrix
) genome. The open reading frames predicting the v-
sis
and c-
sis
gene products coincide with the stop codon of c-
sis
located 123 nucleotides into the fifth region of homology. The overall nucleotide homology was 91 percent with substitutions mainly in the third codon positions within the open reading frame and with greatest divergence within the untranslated 3′ portion of the sequences. The predicted protein products for v-
sis
and c-
sis
are 93 percent homologous. The predicted c-
sis
gene product is identical in 31 of 31 amino acids to one of the published sequences of platelet-derived growth factor. Thus, c-
sis
encodes one chain of human platelet-derived growth factor.
A Common
onc
Gene Sequence Transduced by Avian Carcinoma Virus MH2 and by Murine Sarcoma Virus 3611
Authors: Kan Nancy C. , Flordellis Christos S. , Mark George E. , Duesberg Peter H. , Papas Takis S.
Published: October 2006

A common cellular sequence was independently transduced by avian carcinoma virus MH2 (v-
mht
) and murine sarcoma virus (MSV) 3611 (v-
raf
). Comparison of the nucleotide sequences of v-
mht
and v-
raf
revealed a region of homology that extends over 969 nucleotides. The homology between the corresponding amino acids was about 95 percent with only 19 of 323 amino acids being different. With this example, 5 of the 19 known different viral
onc
genes have been observed in viruses of different taxonomic groups. These data indicate that (i) the number of cellular proto-
onc
genes is limited because, like other viruses of different taxonomic groups, MH2 and MSV 3611 have transduced the same
onc
gene-specific sequences from different cell species and (ii) that specific deletion and linkage of the same proto-
onc
sequences to different viral vector elements affect the
onc
ogenic potential of the resulting viruses. The difference in transformation capabilities of MH2 and MSV 3611 serves as an example.
Cost-Effective Priorities for Cancer Prevention
Authors: Weinstein Milton C.
Published: October 2006

Faced with limited resources, the United States must set priorities for research to identify preventable causes of cancer. A quantitative approach to priority setting, based on principles of decision analysis and cost-effectiveness analysis, can offer guidance in this process. An illustrative application of such a model suggests that the National Institutes of Health-supported clinical trial of dietary β-carotene offers a greater expected reduction in cancer mortality per research dollar than carcinogen bioassays of high-volume industrial chemicals such as
p
-dichlorobenzene. National research priorities should reflect the relative cost-effectiveness of such investments.
Fluorescence-Line-Narrowed Spectra of Polycyclic Aromatic Carcinogen-DNA Adducts
Authors: Heisig Volker , Jeffrey Alan M. , McGlade Michael J. , Small Gerald J.
Published: October 2006

The laser excited fluorescence-line-narrowed spectrum of DNA modified with (±)-
r
-7,
t
-8-dihydroxy-
t
-9,10-epoxy-7,8,9,10-tetrahydrobenzo[
a
]pyrene (BPDE), the ultimate carcinogenic metabolite of benzo[
a
]pyrene (BP), has been obtained in a water-glycerol-ethanol glass at 4.2 K. The spectrum was well resolved and highly characteristic of the chromophore. Comparisons were made between the spectrum of this modified DNA and the isolated deoxyguanosine-BPDE adduct and a series of other 7,8,9,10-tetrahydro-BP (THBP) derivatives. 9-Hydroxy-BP 4,5-oxide, which is also involved in the binding of BP to DNA, and THBP have very similar conventional broadband fluorescence spectra. However, the fluorescence-line-narrowed spectra of their derivatives were readily distinguishable either as individual components or as mixtures.
Phosphorylation of Smooth Muscle Myosin: Evidence for Cooperativity Between the Myosin Heads
Authors: Persechini A. , Hartshorne D. J.
Published: October 2006

The relationship between the actin-activated adenosinetriphosphatase activity of smooth muscle myosin and the extent of myosin light chain phosphorylation is nonlinear. It is suggested that the phosphorylation of the two heads of smooth muscle myosin is an ordered process and that the two heads are influenced by cooperative interactions.
Neuropeptides: Mediators of Behavior in
Aplysia
Authors: Scheller Richard H. , Kaldany Rashad-Rudolf , Kreiner Thane , Mahon Anne C. , Nambu John R. , Schaefer Mark , Taussig Ronald
Published: October 2006

The
Aplysia
neuroendocrine system is a particularly advantageous model for cellular and molecular studies because of the relatively small number and large size of its component neurons. Recombinant DNA techniques have been used to isolate the genes that encode the precursors of peptides expressed in identified neurons of known function. The organization and developmental expression of these genes have been examined in detail. Several of the genes encode precursors of multiple biologically active peptides that are expressed in cells which also contain classical transmitters. These studies, as well as immunohistochemical studies and the use of intracellular recording and voltage clamp techniques are the first steps toward revealing the mechanisms by which neuropeptides govern simple behaviors.
Loss of Adhesion of Murine Erythroleukemia Cells to Fibronectin During Erythroid Differentiation
Authors: Patel Vikram P. , Lodish Harvey F.
Published: October 2006

Uninduced murine erythroleukemia cells specifically attached to fibronectin-coated dishes but not to dishes coated with laminin or type I or IV collagen. Dimethyl sulfoxide-induced differentiation of these cells caused a dramatic decrease in adhesion to fibronectin that was correlated with synthesis of the erythrocyte glycoprotein "band III," a membrane marker of the differentiated erythrocyte. Loss or modification of fibronectin binding sites on the cell surface during erythroid differentiation may cause the release of reticulocytes from the interstitial matrix of bone marrow into the blood.
Gene Reactivation in Erythrocytes: Nuclear Transplantation in Oocytes and Eggs of
Rana
Authors: DiBerardino Marie A. , Hoffner Nancy J.
Published: October 2006

Adult erythrocyte nuclei of
Rana
, transplanted and incubated in the cytoplasm of maturing oocytes, direct matured oocytes to form swimming tadpoles. These results demonstrate that nuclei of noncycling and terminally differentiated erythrocytes contain the genes to specify tadpole development, and conditioning these nuclei in the cytoplasm of oocytes leads to a widespread reactivation of dormant genes.
Aggregation Effects on Oxygen Binding of Sickle Cell Hemoglobin
Authors: Gill S. J. , Sköld R. , Fall L. , Shaeffer T. , Spokane P. , Wyman J.
Published: October 2006

Deoxygenation of concentrated solutions (0.33 gram per milliliter) of sickle cell hemoglobin show (i) a "crisis point" where the oxygen binding curve is unusually steep (Hill coefficient of 5 to 6), and (ii) a simultaneous increase in light scattering. Nearly identical oxygen binding curves are obtained upon oxygenation and deoxygenation of these solutions. The influence of aggregation is to shift the curve toward higher pressures.
Magnetometry of Ingested Particles in Pulmonary Macrophages
Authors: Valberg Peter A.
Published: October 2006

Sensitive magnetometry has shown that, after inhalation of airborne magnetic dust by humans or animals, particles retained within the lungs rotate. A number of mechanisms for this rotation have been proposed, including motions of breathing, particle thermal energy, cardiac pulsations, surface fluid flows, and macrophage cytoplasmic movements. In this study the cellular mechanism was examined by magnetometry and videomicroscopy of pulmonary macrophages removed from hamster lungs 1 day after inhalation of a maghemite (γ-Fe
2
O
3
) aerosol. The field remaining after magnetization was measured in adherent cells and was found to decay rapidly to 30 percent of its initial magnitude within 12 minutes. The remanent-field decay rate was slowed by inhibitors of cytoplasmic motion. Videomicroscopy of pulmonary macrophages with phagocytized γ-Fe
2
O
3
showed amoeboid motions that rotated the particles away from their original direction of magnetization. The results confirm that macrophage cytoplasmic movement is a primary cause of remanent-field decay in lungs and that magnetometry can be used to quantify intracellular contractile activity.
Dynamic Heterogeneity: Rapid Generation of Metastatic Variants in Mouse B16 Melanoma Cells
Authors: Hill R. P. , Chambers A. F. , Ling V. , Harris J. F.
Published: October 2006

The ability of clonally derived lines of B16F1 and B16F10 melanoma cells to form experimental metastases in C57BL mice after intravenous injection was examined. Luria-Delbruck fluctuation analysis was applied to the results obtained with parallel subclones grown to small population sizes before testing for metastatic ability. The analysis demonstrated that variant cells capable of forming experimental metastases were generated in B16F1 cell populations at an effective rate of about 1.3 × 10
-5
per cell per generation while in B16F10 cell populations the effective rate of production was about 5 × 10
-5
per cell per generation. These results are consistent with a dynamic heterogeneity model of tumor progression. They suggest that the majority of cells in both lines are effectively nonmetastatic and that the higher metastatic ability of the B16F10 population may be due in part to a higher rate of generation of metastatic variants.
Adsorption to Fish Sperm of Vertically Transmitted Fish Viruses
Authors: Mulcahy Dan , Pascho Ronald J.
Published: October 2006

More than 99 percent of a vertically transmitted fish rhabdovirus, infectious hematopoietic necrosis virus, was removed from suspension in less than 1 minute by adsorption to the surface membrane of sperm from two genera of salmonid fishes. The vertically transmitted, infectious pancreatic necrosis virus adsorbed to a lesser degree, but no adsorption occurred with a second fish rhabdovirus that is not vertically transmitted. Such adsorption may be involved in vertical transmission of these viruses.
Scoliosis in Chickens: Responsiveness of Severity and Incidence to Dietary Copper
Authors: Opsahl William , Abbott Ursula , Kenney Cristina , Rucker Robert
Published: October 2006

The severity and incidence of spinal lesions were manipulated in a line of chickens susceptible to scoliosis by varying their dietary intake of copper. A decrease in expression of the lesion was related to increased intake of copper. The change in expression, however, appeared to be related only indirectly to the defects in collagen cross-linking, maturation, and deposition known to be associated with dietary copper deficiency. Thus, a dietary constituent in the range of normal intakes may act as an environmental factor in the expression of scoliosis.
Creationism in 20th-Century America
Authors: Numbers Ronald L.
Published: October 2006

As the crusade to outlaw the teaching of evolution changed to a battle for equal time for creationism, the ideological defenses of that doctrine also shifted, from biblical to scientific grounds. The development of "scientific creationism" is here described.
Sex Preselection in Mammals? Separation of Sperm Bearing Y and "O" Chromosomes in the Vole
Microtus oregoni
Authors: Pinkel Daniel , Gledhill Barton L. , Lake Suzanne , Stephenson Diane , Van Dilla Marvin A.
Published: October 2006

The two sex determining sperm populations of the vole Microtus oregoni were separated according to DNA content by use of flow sorting instrumentation. Although the sperm were not viable, they should be useful for addressing the question of haploid expression of genes linked to sex chromosomes and for efficiently searching for biochemical markers that differentiate the two populations.
Development of Contrast Sensitivity in Infant
Macaca nemestrina
monkeys
Authors: Boothe Ronald G. , Williams Rick A , Kiorpes Lynne , Teller Davida Y
Published: October 2006

During an infant monkey's first 28 postnatal weeks, the visual contrast sensitivity function develops its characteristic adult form. Contrast sensitivity is depressed relative to that of the adult for all spatial frequencies during the early postnatal weeks. Absolute sensitivity to frequencies below 5 cycles per degree approaches adult levels by 20 weeks after birth, whereas sensitivity to fine spatial detail continues to develop through 28 weeks. The results imply that the development of primate spatial vision is more complex than just an improvement in the ability to resolve acuity gratings.
Prolongation of Islet Xenograft Survival Without Continuous Immunosuppression
Authors: Lacy Paul E. , Davie Joseph M. , Finke Edward H.
Published: October 2006

The survival of isolated rat islets transplanted into diabetic mice was prolonged markedly by maintaining the rat islets in vitro at 24°C for 7 days before transplantation and administering to the recipients a single injection of antiserum to mouse and rat lymphocytes shortly before transplantation.
Spontaneous Diabetes in Rats: Destruction of Islets Is Prevented by Immunological Tolerance
Authors: Naji Ali , Silvers Willys K. , Bellgrau Don , Barker Clyde F.
Published: October 2006

Spontaneous diabetes occurring in "BB" rats (derived from a colony of outbred Wistar rats) is the result of destruction of pancreatic islets by infiltrating mononuclear cells (insulitis) and may be a disease very similar to human juvenile onset diabetes. Both diseases probably have an autoimmune etiology. Evidence is presented that islets transplanted to diabetic BB rats are destroyed by the original disease process. Inoculation of bone marrow from normal (nondiabetes-susceptible) rat donors into neonatal BB recipients usually prevents the development of hyperglycemia.
Calcium Ionophore Polarizes Ooplasmic Segregation in Ascidian Eggs
Authors: Jeffery William R.
Published: October 2006

Calcium ionophore A23187 promotes ooplasmic segregation and orange crescent formation in eggs of the ascidian
Boltenia villosa
. When eggs were exposed to a gradient of A23187 the orange crescent was induced to form in the region corresponding to the highest concentration of ionophore. This result is consistent with the hypothesis that a local increase in intracellular calcium polarizes cytoplasmic localization in the ascidian embryo.
Parathyroid Hormone: Effects of the 3-34 Fragment in Vivo and Vitro
Authors: McGowan John A. , Chen Tai C. , Fragola Jorge , Puschett Jules B. , Rosenblatt Michael
Published: October 2006

The biologically active fragment of parathyroid hormone, consisting of residues 1-34, and its in vitro antagonist, fragment 3-34, were administered separately or in combination to chronically thyroparathyroidectomized dogs. These fragments were also studied in vitro with dog renal cortical membranes. Fragment 3-34 inhibited the stimulation of adenylate cyclase by fragment 1-34 in vitro, but had no agonist or antagonistic effects on renal phosphate transport in vivo.
Patterns of Human Local Cerebral Glucose Metabolism During Epileptic Seizures
Authors: Engel Jerome , Kuhl David E. , Phelps Michael E.
Published: October 2006

Ictal patterns of local cerebral metabolic rate have been studied in epileptic patients by positron computed tomography with
18
F-labeled 2-fluoro-2-deoxy-D-glucose. Partial seizures were associated with activation of anatomic structures unique to each patient studied. Ictal increases and decreases in local cerebral metabolism were observed. Scans performed during generalized convulsions induced by electroshock demonstrated a diffuse ictal increase and postictal decrease in cerebral metabolism. Petit mal absences were associated with a diffuse increase in cerebral metabolic rate. The ictal fluorodeoxyglucose patterns obtained from patients do not resemble autoradiographic patterns obtained from common experimental animal models of epilepsy.
Nitropyrenes: Isolation, Identification, and Reduction of Mutagenic Impurities in Carbon Black and Toners
Authors: Rosenkranz Herbert S. , McCoy Elena C. , Sanders Daniel R. , Butler Marsha , Kiriazides Demosthenes K. , Mermelstein Robert
Published: October 2006

Extracts of selected xerographic toners and copies were found to be mutagenic in the Salmonella assay. The activity was independent of the xerographic hardware and process and was traced to nitropyrenes present as impurities in the carbon black, the toner colorant. Manufacturing process changes resulted in a substantial reduction of the nitropyrene content of the carbon black and thus in the mutagenicity of the corresponding toners. Nitropyrenes are potent frameshift mutagens, and possible mechanisms for their biological action are discussed.
Autoantibodies to Zona Pellucida: A Possible Cause for Infertility in Women
Authors: Shivers C. Alex , Dunbar Bonnie S.
Published: October 2006

Human and pig ovaries were tested by agar gel diffusion and found to contain several cross-reacting (common) antigens. At least one common antigen was located in the zona pellucida as determined by indirect immunofluorescence. Serum samples from 22 infertile women were tested on pig eggs by immunofluorescence, and six of these samples produced strong and nine produced moderate reactions with the zona pellucida. The autoantibodies may be responsible for infertility in these women.