bluuebunny/crossref_metadata_2025 huggingface dataset:
Light-Induced Phosphorylation of Retina-Specific Polypeptides of
Drosophila
in Vivo
Authors: Matsumoto Hiroyuki , Pak William L.
Published: October 2006

A moderate light stimulus induced isoelectric point (
p
I) changes in three classes of retina-specific polypeptides (80, 49, and 39 kilodaltons) of
Drosophila
in vivo. When inorganic phosphate labeled with phosphorus-32 was fed to flies, the radioactive label was incorporated into these polypeptides during the
p
I changes, indicating light-induced phosphorylation of the polypeptides. A 1-millisecond flash induced a detectable amount of phosphorylation in the 80- and 49-kilodalton polypeptides within 3 seconds. These results, and our previous results with
norpA
mutants, suggest that phosphorylation of these two polypeptides may be involved in some early stages of photoreceptor excitation or its modulation.
Functional Expression of a Cloned I-Aβ
k
Gene in B-Lymphoma Cells
Authors: Ben-Nun Avraham , Glimcher Laurie H. , Weis John , Seidman J. G.
Published: October 2006

The immune response genes of the mouse encode two cell-surface glycoproteins, I-A and I-E, that play critical roles in determining the animal's immune responsiveness. The I-A antigen contains two chains, α and β. A cloned β-chain gene, I-A β
k
, was introduced into B-lymphoma cells that express I-A
d
. The transfected gene was successfully expressed on the cell surface of the recipient cells and was functional in stimulating allospecific T cells.
Cell Surface Changes Associated with Cellular Immune Reactions in
Drosophila
Authors: Nappi Anthony J. , Silvers Michael
Published: October 2006

In
Drosophila melanogaster
a temperature-induced change in immune competence accompanies cell surface alterations that cause its blood cells to adhere and to encapsulate a parasite. At 29°C the blood cells of the tumorous-lethal (
Tum
1
) mutant show a high degree of immune competence and encapsulate the eggs of the parasitic wasp
Leptopilina heterotoma
. At 21°C the blood cells are essentially immune incompetent. High percentages of lectin binding cells were found under conditions which potentiated cellular encapsulation responses. Some immune reactive blood cells did not bind lectin. The low percentages of lectin binding cells in susceptible hosts suggest that developing parasites alter the cell surface of the blood cells of immune reactive hosts.
Chromosomal Location of Human T-Cell Receptor Gene T
i
β
Authors: Barker P. E. , Ruddle Frank H. , Royer Hans-Dieter , Acuto Oreste , Reinherz Ellis L.
Published: October 2006

A complementary DNA probe corresponding to the β-chain gene of T
i
, the human T lymphocyte receptor, has been molecularly cloned. The chromosomal origin of the T
i
β gene was determined with the complementary DNA by screening a series of 12 cell hybrid (mouse × human) DNA's containing overlapping subsets of human chromosomes. DNA hybridization (Southern) experiments showed that the human T
i
β gene resides on chromosome 7 and is thus not linked to the immunoglobulin loci or to the major histocompatibility locus in humans.
Myoadenylate Deaminase Deficiency: A New Disease of Muscle
Authors: Fishbein William N. , Armbrustmacher Vernon W. , Griffin Joe L.
Published: October 2006

Five cases of a new disease presented with muscular weakness or cramping after exercise; three of the cases also had an elevated serum creatine phosphokinase. Muscle biopsies were histologically normal but lacked adenylate deaminase by stain and solution assay, while the erythrocyte isozyme was normal. A clinical diagnostic test has been developed, and the human enzyme was separated by acrylamide-gel electrophoresis.
The Problem of Defensive Medicine
Authors: Tancredi Laurence R. , Barondess Jeremiah A.
Published: October 2006

Defensive medicine—the use of diagnostic and end-treatment measures explicitly for the purposes of averting malpractice suits—is frequently cited as one of the least desirable effects of the current rise in medical litigation. Many physicians and policy-makers claim that defensive medicine is responsible not only for the increasing costs of health care but the exposing of patients to significant risks of harm from unnecessary procedures. Very little solid information is available about defensive medicine. The studies that have been conducted have been fraught with statistical difficulties and are by no means definitive. Even more important than the issue of defensive medicine is the more basic problem of our system of compensation for medical injuries.
Spinal Sympathetic Pathway: An Enkephalin Ladder
Authors: Romagnano M. A. , Hamill R. W.
Published: October 2006

Enkephalin distribution was examined in autonomic areas of the rat thoracic spinal cord. The localization of enkephalin fibers coincided with nuclear regions containing sympathetic preganglionic neurons. Horizontal sections revealed a pattern for enkephalin fibers resembling Laruelle's description of the localization of sympathetic preganglionic neurons as rungs of a ladder.
Enhancement of Sexual Motivation in Male Rats by Yohimbine
Authors: Clark John T. , Smith Erla R. , Davidson Julian M.
Published: October 2006

Yohimbine hydrochloride, an α
2
-adrenoceptor antagonist, increased sexual motivation in male rats as evidenced by increased mounting performance in mating tests conducted after genital anesthetization, increased percentage of male rats ejaculating in their first heterosexual encounter, and induction of copulatory behavior in sexually inactive male rats. These observations lead to the suggestion that α-adrenoceptors are important modulators of sexual arousal in intact male rats. These results indicate that pharmacological treatment of sexual (libido) dysfunction may be useful.
Enhanced Neural Response to Familiar Olfactory Cues
Authors: Coopersmith Robert , Leon Michael
Published: October 2006

Norway rat pups have an enhanced olfactory bulb response to a familiar odor. A specific complex of glomeruli showed increased carbon-14-labeled 2-deoxy-D-glucose uptake in response to peppermint odor in 19-day-old pups exposed to peppermint on days 1 to 18 after birth, relative to control pups that had been exposed to clean air. The increased activity was not due to increased respiration of the familiar odor.
The Molecular Structure of a DNA-Triostin A Complex
Authors: Wang Andrew H.-J. , Ughetto Giovanni , Quigley Gary J. , Hakoshima Toshio , van der Marel Gijs A. , van Boom Jacques H. , Rich Alexander
Published: October 2006

The molecular structure of triostin A, a cyclic octadepsipeptide antibiotic, has been solved complexed to a DNA double helical fragment with the sequence CGTACG (C, cytosine; G, guanine; T, thymine; A, adenine). The two planar quinoxaline rings of triostin A bis intercalate on the minor groove of the DNA double helix surrounding the CG base pairs at either end. The alanine residues form hydrogen bonds to the guanines. Base stacking in the DNA is perturbed, and the major binding interaction involves a large number of van der Waals contacts between the peptides and the nucleic acid. The adenine residues in the center are in the syn conformation and are paired to thymine through Hoogsteen base pairing.
Control of Neuronal Gene Expression
Authors: Sutcliffe J. Gregor , Milner Robert J. , Gottesfeld Joel M. , Reynolds Wanda
Published: October 2006

Some 30,000 genes are expressed exclusively in the rat brain, many of which contain a genetic element called an identifier sequence located in at least one of their introns. The identifier sequences are transcribed by RNA polymerase III exclusively in neurons to produce two RNA species, BC1 and BC2, of 160 and 100 to 110 nucleotides. This transcriptional event may define regions of chromatin that contain neuronal-specific genes and may poise these genes for transcription by polymerase II by rendering the gene promoters accessible to soluble trans-acting molecules.
Temporal Lobe Lesions and Perception of Species-Specific Vocalizations by Macaques
Authors: Heffner Henry E. , Heffner Rickye S.
Published: October 2006

Japanese macaques were trained to discriminate two forms of their coo vocalization before and after unilateral and bilateral ablation of the temporal cortex. Unilateral ablation of the left superior temporal gyrus, including auditory cortex, resulted in an initial impairment in the discrimination, but similar unilateral ablation of the right superior temporal gyrus had no effect. Bilateral temporal lesions including auditory cortex completely abolished the ability of the animals to discriminate their coos. Neither unilateral nor bilateral ablation of cortex dorsal to and sparing the auditory cortex had any effect on the discrimination. The perception of species-specific vocalizations by Japanese macaques seems to be mediated by the temporal cortex, with the left hemisphere playing a predominant role.
Trends in Analytical Instrumentation
Authors: McLafferty Fred W.
Published: October 2006

Methods for deriving chemical information from a variety of systems and environments have changed dramatically in the last decade. Unique principles from physics, chemistry, and biology are the basis for sophisticated instruments that incorporate computers for data acquisition, reduction, and interpretation. Such analytical systems have shown orders-of-magnitude improvements in sensitivity, specificity, and speed, yet with greater simplicity and lower price. The increasing importance of analytical instrumentation requires reexamination of its coverage in educational curricula and of the role of the analytical chemist in its further development and application.
Heterochronic Mutants of the Nematode
Caenorhabditis elegans
Authors: Ambros Victor , Horvitz H. Robert
Published: October 2006

Mutations in the
Caenorhabditis elegans
genes
lin-14
,
lin-28
, and
lin-29
cause heterochronic developmental defects: the timing of specific developmental events in several tissues is altered relative to the timing of events in other tissues. These defects result from temporal transformations in the fates of specific cells, that is, certain cells express fates normally expressed by cells generated at other developmental stages. The identification and characterization of genes that can be mutated to cause heterochrony support the proposal that heterochrony is a mechanism for phylogenetic change and suggest cellular and genetic bases for heterochronic variation.
A Major Human Histone Gene Cluster on the Long Arm of Chromosome 1
Authors: Green L. , Van Antwerpen R. , Stein J. , Stein G. , Tripputi P. , Emanuel B. , Selden J. , Croce C.
Published: October 2006

A human histone gene cluster was assigned to chromosome 1 by Southern blot analysis of DNA's from a series of mouse-human somatic cell hybrids with
32
P -labeled cloned human H4 and H3 histone DNA as probes. Localization of this histone gene cluster on the long arm of chromosome 1 was confirmed by in situ hybridization of this DNA probe to metaphase chromosomes.
The Long Terminal Repeat Sequences of a Novel Human Endogenous Retrovirus
Authors: O'Connell Catherine D. , Cohen Maurice
Published: October 2006

The complete nucleotide sequence of both the 5′ and 3′ long terminal repeats (LTR's) has been determined for a human endogenous retroviral genome. These sequences are 593 and 590 nucleotides long and have diverged from one another by 8.8 percent. The LTR's resemble those of functional mammalian type C retroviruses in length and in the presence and location of eukaryotic promoter sequences. The 5′ LTR is followed by a presumptive primer binding site unlike that of any known mammalian type C retrovirus, exhibiting 17 out of 18 nucleotides complementary to arginine transfer RNA rather than proline transfer RNA.
Morphine Analgesia Potentiated But Tolerance Not Affected by Active Immunization Against Cholecystokinin
Authors: Faris Patricia L. , McLaughlin Carol L. , Baile Clifton A. , Olney John W. , Komisaruk Barry R.
Published: October 2006

Administration of cholecystokinin was recently found to attenuate opiate analgesia. In the present study, the role of endogenous cholecystokinin in opiate analgesia was examined. Endogenously released cholecystokinin was sequestered by antibodies to cholecystokinin developed in response to an active immunization procedure. Morphine analgesia was potentiated and prolonged in rats immunized against cholecystokinin. The rate of development of morphine tolerance, however, was not affected by the antibodies. Endogenous cholecystokinin appears to function as a short-term modulator of opiate action.
Intragastric Self-Infusion of Ethanol by Ethanol-Preferring and -Nonpreferring Lines of Rats
Authors: Waller Marshall B. , McBride William J. , Gatto Gregory J. , Lumeng Lawrence , Li Ting-Kai
Published: October 2006

An ethanol-preferring line of rats, developed by selective breeding, consumed as much as 9.4 ± 1.7 grams of ethanol per kilogram of body weight per day through intragastric self-infusions, yielding blood ethanol concentrations of 92 to 415 milligrams per 100 milliliters. By contrast, the ethanol-nonpreferring line self-administered only 0.7 ± 0.2 gram per kilogram per day. These findings indicate that the reinforcing effect of ethanol is postabsorptive and is not mediated by the drug's smell or taste. Hence the ethanol-preferring line of rats may be a suitable animal model of alcoholism.
Transcriptional Regulation of Globin Gene Expression in the Human Erythroid Cell Line K562
Authors: Charnay Patrick , Maniatis Tom
Published: October 2006

The effect of hemin on the rate of synthesis and the level of globin messenger RNA's in the human erythroid cell line K562 was examined by means of cloned hybridization probes specific for each of the human embryonic, fetal, and adult globin genes. Hemin increases both the rate of transcription and the level of accumulation of ζ-, ε-, γ-, and α-globin messenger RNA's by a factor of 3 to 5. Thus, hemin induction of globin gene expression in K562 cells is at the level of transcription.
Inhibitory Role of the Endothelium in the Response of Isolated Coronary Arteries to Platelets
Authors: Cohen Richard A. , Shepherd John T. , Vanhoutte Paul M.
Published: October 2006

Aggregating autologous platelets caused contraction of isolated rings of canine left circumflex arteries. The contractions were augmented after removal of the endothelium and were attenuated by serotonergic antagonists. During contraction caused by prostaglandin F
2α
, aggregating platelets caused a transient increase in tension followed by a profound relaxation of arteries with endothelium, but caused only further contraction of arteries without endothelium. These observations demonstrate the importance of the vascular endothelium in opposing the constriction of coronary vessels caused by 5-hydroxytryptamine and other substances released from aggregating platelets.
Appearance of a New Nucleosomal Protein During Differentiation of Human Leukemia (HL-60) Cells
Authors: Chou Robin H. , Chervenick Paul A. , Barch Davis R.
Published: October 2006

A 60-kilodalton protein was identified in chromatin digested by micrococcal nuclease during retinoic acid-induced differentiation of human leukemia (HL-60) cells to mature-like granulocytes. The protein was not detected in a retinoic acid-resistant variant of the HL-60 cell line treated with retinoic acid, in HL-60 cells induced with dimethyl sulfoxide, or in normal human granulocytes. This protein may have an important role in the regulation of retinoic acid-induced leukemic cell differentiation.
Altered Transcription of the c-
abl
Oncogene in K-562 and Other Chronic Myelogenous Leukemia Cells
Authors: Collins Steven J. , Kubonishi Ichiro , Miyoshi Isao , Groudine Mark T.
Published: October 2006

Expression of the cellular
abl
(c-
abl
) oncogene was studied in K-562 and other chronic myelogenous leukemia (CML) cells and cell lines by means of Northern blot hybridization. In contrast to non-CML cells, which contained 7.4- and 6.8-kilobase
abl
-related transcripts, the CML cells contained a predominant and novel 8.2-kilobase
abl
-related RNA. In addition, the levels of
abl
-related message were up to eight times higher in CML cell lines from patients at the blast crisis stage of the disease compared with CML cells obtained during the chronic phase and with non-CML cells.
The Emergence of the Biology of Forest and Range
Authors: Taylor Walter P.
Published: October 2006

Whereas, in most lines of agriculture over-production is so outstanding a phenomenon that curtailment is widely recommended by economists, precisely the opposite is the case in silviculture and forage production. America's wild crop of timber and of feed for livestock falls far short of the demand. Careful attention must be given to all the conditions surrounding the growth of these crops. Among the factors of major importance are the native animals of forest and range lands. Some are pests; others are beneficial. Most play mixed rôles. Efficient production of trees and forage necessitates thorough-going study of the life histories and ecology of all the predominants, both plants and animals. Many animals, especially fishes, birds and mammals, are themselves of extraordinary value for recreation, study, and as a source of income. In some instances the value of the animals on a given area may exceed that of forage or trees. The production of wild life should be more than an incident or by-product of forest and range management. The objective should be maximum continuing values from each area. Attainment of this objective necessitates additional information and increasingly enlightened administration. Research is the foundation of our present prosperity. It must be the corner-stone of future advance. "The application of traditional methods will no longer suffice." Biology must participate fully in the solution of the many problems involved.
Identification of the c-
myc
Oncogene Product in Normal and Malignant B Cells
Authors: Giallongo Agata , Appella Ettore , Ricciardi Robert , Rovera Giovanni , Croce Carlo M.
Published: October 2006

Antiserum to a synthetic peptide corresponding to the carboxyl-terminus of the human c-
myc
protein immunoprecipitated a 48,000-dalton protein from a number of normal and malignant human and mouse cells. The size of the protein is consistent with the potential coding region predicted from the c-
myc
nucleotide sequence, and is the same for malignant cells carrying either a rearranged or an unrearranged c-
myc
oncogene. Because c-
myc
transcripts are expressed at higher levels in malignant than in normal B cells, it appears that an increased level of the c-
myc
protein rather than a change in the gene product is the relevant factor in determining transformation.
Dependence of Thymus Development on Derivatives of the Neural Crest
Authors: Bockman Dale E. , Kirby Margaret L.
Published: October 2006

Elimination of limited areas of the cephalic neural crest in stage 9 or 10 chick embryos markedly reduced the size of the thymus gland or resulted in its absence. Small thymic lobes contained both thymocytes and epithelial cells but showed delayed development. Parathyroid and thyroid glands sometimes were reduced in size or missing from the normal location on one or both sides. Heart defects were consistently present. Thymus development may depend on direct interaction of mesenchymal derivatives of the neural crest with pharyngeal epithelium. Multiple defects, such as the Di George syndrome, may result from failure of neural crest derivatives to migrate and interact properly.
Inhibition of Dihydropteridine Reductase by Novel 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Analogs
Authors: Abell Creed W. , Shen Rong-Sen , Gessner Wieslaw , Brossi Arnold
Published: October 2006

Hydroxylated derivatives of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a nigrostriatal neurotoxin in humans and primates, noncompetitively inhibited dihydropteridine reductase from human liver and rat striatal synaptosomes in vitro at micromolar concentrations. In contrast, MPTP and its chloro- and norderivatives did not inhibit this enzyme at lower than millimolar concentrations. Dihydropteridine reductase converts dihydrobiopterin to tetrahydrobiopterin, the required cofactor for the hydroxylation of aromatic amino acids during the synthesis of dopamine and serotonin.
Oxygen Tension Regulates the Expression of Angiogenesis Factor by Macrophages
Authors: Knighton David R. , Hunt Thomas K. , Scheuenstuhl Heinz , Halliday Betty J. , Werb Zena , Banda Michael J.
Published: October 2006

When cultured in a hypoxic environment similar to that found in the center of a wound, macrophages secreted active angiogenesis factor into the medium. Under conditions similar to those of well-oxygenated tissue, macrophages did not secrete active angiogenesis factor. Macrophages that secreted the factor at hypoxic conditions stopped secreting it when returned to room air. Thus the control of angiogenesis in wound healing may be the result of macrophages responding to tissue oxygen tension without the necessity of interacting with other cell types or biochemical signals.
Stress-Induced Suppression of Immunity in Adrenalectomized Rats
Authors: Keller Steven E. , Weiss Jay M. , Schleifer Steven J. , Miller Neil E. , Stein Marvin
Published: October 2006

Stress-induced suppression of lymphocyte stimulation by phytohemagglutinin was demonstrated in isolated lymphocytes and in cultures of whole blood from adrenalectomized rats. The results demonstrate that corticosteroid independent mechanisms participate in the suppression of lymphocyte function by stressors. Stress-induced lymphopenia, however, was found to be adrenal dependent, indicating that the modulation of immunity by stress is complex and multidetermined.
Type II Collagen-Induced Autoimmune Endolymphatic Hydrops in Guinea Pig
Authors: Yoo T. J. , Yazawa Y. , Tomoda K. , Floyd R.
Published: October 2006

Endolymphatic hydrops was induced in guinea pigs by immunizing them with native bovine type II collagen. Histopathologic changes consisted of moderate extension of the Reissner's membrane, spiral ganglion degeneration, atrophied organ of Corti, and mild atrophy of the surface epithelium in the endolymphatic duct. These findings suggest that an immune response directed against type II collagen—a type of collagen found in the membranous labyrinth, subepithelial layer of the endolymphatic duct, spiral ligament, and enchondral layer of the otic capsule—may induce endolymphatic hydrops.
Sex Differences in Serotonin 1 Receptor Binding in Rat Brain
Authors: Fischette Christine T. , Biegon Anat , McEwen Bruce S.
Published: October 2006

Male and female rats exhibit sex differences in binding by serotonin 1 receptors in discrete areas of the brain, some of which have been implicated in the control of ovulation and of gonadotropin release. The sex-specific changes in binding, which occur in response to the same hormonal (estrogenic) stimulus, are due to changes in the number of binding sites. Castration alone also affects the number of binding sites in certain areas. The results lead to the conclusion that peripheral hormones modulate binding by serotonin 1 receptors. The status of the serotonin receptor system may affect the reproductive capacity of an organism and may be related to sex-linked emotional disturbances in humans.
Benzoquinolinediones: Activity as Insect Teratogens
Authors: Walton Barbara T. , Ho C.-H. , Ma C. Y. , O'Neill E. G. , Kao G. L.
Published: October 2006

Morphological abnormalities including extra compound eyes, extra heads, and distally duplicated legs were generated in cricket embryos by treating eggs with single doses of either benz[
g
]isoquinoline-5,10-dione or benzo[
h
]quinoline-5,6-dione. Slight structural modifications of the molecules resulted in a loss of teratogenic activity, although embryotoxicity occurred. These potent insect teratogens can be used for analysis of developmental events during embryogenesis.
Radiation Inactivation of Glutamate Dehydrogenase Hexamer: Lack of Energy Transfer Between Subunits
Authors: Kempner E. S. , Miller J. H.
Published: October 2006

The effects of ionizing radiation on glutamate dehydrogenase and on fluorescein isothiocyanate-tagged glutamate dehydrogenase were analyzed by target theory. Enzymatic activity, fluorescence, and the survival of the 56,000-dalton monomer subunit were determined on frozen samples irradiated at -135°C and on lyophilized samples irradiated at either -135°C or +30°C. The effects of temperature were the same for all three parameters. Enzymatic activity was lost after small doses of high-energy electrons, whereas fluorescence and monomer subunits survived much larger doses of radiation. Target analysis revealed that the functional unit size for enzymatic activity was the hexamer, confirming both the earlier radiation study and conventional biochemical analyses. Target sizes obtained from fluorescence and subunit structure measurements were close to that of the monomer. These results indicate that the primary ionization caused by electron bombardment results in damage to a single polypeptide strand and that there is no massive transfer of radiation energy to other units in the hexamer. The large target size observed for enzymatic activity appears to be a structural requirement for the simultaneous presence of six intact subunits rather than the result of the spread of energy from the initial site to adjacent chains with consequent damage to other subunits.
Long-Lived Oxidants Generated by Human Neutrophils: Characterization and Bioactivity
Authors: Weiss S. J. , Lampert M. B. , Test S. T.
Published: October 2006

Human neutrophils were found to generate an unusual class of oxidants with a half-life of approximately 18 hours and with characteristics similar to, if not identical with, those of
N
-chloroamines. These neutrophil-derived
N
-chloroamines have sufficient oxidizing potential to attack sulfhydryl- or thioether-containing compounds and can react with both a methionine-containing chemotactic peptide and a plasma protease inhibitor. As judged by their stability and selective reactivity, the
N
-chloroamines generated by stimulated neutrophils may play an important role in the local and systemic regulation of inflammatory events in vivo.
Specific Endocrine Tissue Marker Defined by a Monoclonal Antibody
Authors: Lloyd Ricardo V. , Wilson Barry S.
Published: October 2006

One of two mouse monoclonal antibodies (LK2H10) produced by hybridoma technology against a human endocrine tumor (pheochromocytoma) demonstrated specific immunoreactivity for 69 normal and neoplastic endocrine cells and tissues known to contain secretory granules. This immunoreactivity was specific, since other normal tissues, tumors from endocrine cells without granules, and tumors from other nonendocrine tissues were negative when tested with antibody LK2H10. The antibody reacted with human fetal adrenal medulla and human pancreatic endocrine cells and with adrenal medullary cells from monkeys and pigs. The antigen detected by antibody LK2H10 is associated with cytoplasmic secretory granules, has an estimated molecular weight of 68,000, and may be related to human chromogranin.
Law and Science Policy in Federal Regulation of Formaldehyde
Authors: Ashford Nicholas A. , Ryan C. William , Caldart Charles C.
Published: October 2006

An examination of the way in which the Environmental Protection Agency, Occupational Safety and Health Administration, and Consumer Product Safety Commission each responded to evidence of formaldehyde's carcinogenicity in animal systems reveals the interplay between politics and science policy in regulatory determinations. In some cases there were significant and unjustified departures from reasoned decision-making. Agency decisions not to take action deserve special attention by citizens, the Congress, and the judiciary to ensure that federal regulatory agencies take the necessary steps to protect the public from significant health, safety, and environmental risks.
Comparison of Rhapidosomes and Asbestos Microfibrils
Authors: Hutchison W. G. , Harker R. Ian , Allen Mary M.
Published: October 2006

Rhapidosomes (cylindrical nucleoprotein rods of bacterial origin) show great structural similarity to the microfibrils of chrysotile asbestos when negatively stained and observed with the electron microscope. If the negative stain is omitted, the asbestos retains its structural detail whereas the rhapidosomes appear to be unstructured bodies. When the microscope is adjusted into a selected area diffraction mode, the asbestos shows characteristic electron diffraction patterns whereas the rhapidosomes appear to be amorphous to electron diffraction.
Initiation of Light Adaptation in Barnacle Photoreceptors
Authors: Strong Judith , Lisman John
Published: October 2006

Intracellular recordings were used to measure the action spectrum of light adaptation in barnacle photoreceptors. The action spectrum closely resembles the absorption spectrum of rhodopsin (λ
max
at 530 nanometers) and is clearly different from that of metarhodopsin (λ
max
at 495 nanometers). These results suggest that absorption of light by rhodopsin initiates both excitation and light adaptation. The previously reported antagonistic process initiated by metarhodopsin does not appear to play a role at moderate light intensities.
Intellectual Status of Working-Class Children Adopted Early into Upper-Middle-Class Families
Authors: Schiff Michel , Duyme Michel , Dumaret Annick , Stewart John , Tomkiewicz Stanislaw , Feingold Josue
Published: October 2006

Failure rates observed (13 ± 6 percent for school failures, 17 ± 5 percent for scores below 95 on a collective IQ test) were far below those expected from the social class of birth (55 percent, 51 percent) or observed in a control group (56 ± 8 percent, 49 ± 9 percent) but close to those expected from the social class of adoption (15 percent, 15 percent).
Nuclear Waste: Increasing Scale and Sociopolitical Impacts
Authors: LaPorte Todd R.
Published: October 2006

The article argues that insufficient attention has been paid to the operational aspects of the U.S. radioactive waste management system when it grows to the scale necessary to handle wastes produced by a fully deployed plutonium economy. Without such information, many of the unsettling speculations which have become part of the public debate and are summarized herein cannot be clearly addressed. The article then outlines the types of information necessary to begin estimating the costs and consequences of radioactive waste management. Finally, an index of social exposure to radioactive hazard is proposed to improve the basis for policy decisions in this area.
Genomic Masking of Nondefective Recombinant Murine Leukemia Virus in Moloney Virus Stocks
Authors: Fischinger Peter J. , Blevins Charlotte S. , Dunlop Nancy M.
Published: October 2006

HIX virus cloned from Moloney leukemia virus stocks is a nondefective, leukemogenic, and amphotropic murine oncornavirus with a recombinant-type major glycoprotein. Although Moloney leukemia virus stocks generally contain little or no free amphotropic virus, dilution analysis of several virus stocks and the examination of virus progeny from individual foci revealed that HIX virus is present and functionally coated with ecotropic Moloney virus envelopes. Because most mice have serum factors that inactivate recombinant viruses, masking may represent a general survival mechanism for HIX as well as other analogous recombinant viruses.
Development of Gynogenetic Eggs in the Mouse: Implications for Parthenogenetic Embryos
Authors: Surani M. Azim H. , Barton Sheila C.
Published: October 2006

Mouse eggs with different genetic constitutions were prepared by micromanipulation of fertilized diploids and triploids. The diploid gynogenones, activated by the male gamete which was then removed, developed at best to about the 25-somite stage as did the genetically similar diploid parthenogenones stimulated to develop in the complete absence of the male gamete. The failure of development to term in both cases may be due to homozygosity and does not appear to be due to a lack of extragenetic contribution from spermatozoa.
Dynorphin-A-(1-8) Is Contained Within Vasopressin Neurosecretory Vesicles in Rat Pituitary
Authors: Whitnall Mark H. , Gainer Harold , Cox Brian M. , Molineaux Christopher J.
Published: October 2006

Dynorphin-A-(1-8), an opioid peptide widely distributed in the rat central nervous system, is present in vasopressin-containing neurosecretory cells terminating in the neural lobe of the pituitary. Electron microscopic immunocytochemistry reveals that dynorphin-A-(1-8) is contained within the same neurosecretory vesicles as vasopressin and vasopressin-associated neurophysin in the neural lobe of the rat. The results indicate that dynorphin may be released in the pituitary concomitantly with vasopressin during the antidiuretic response.
Latrunculins: Novel Marine Toxins That Disrupt Microfilament Organization in Cultured Cells
Authors: Spector Ilan , Shochet Nava R. , Kashman Yoel , Groweiss Amiram
Published: October 2006

Two toxins, latrunculins A and B, which contain a new class of 16- and 14-membered marine macrolides attached to the rare 2-thiazolidinone moiety, were purified recently from the Red Sea sponge
Latrunculia magnifica
. The effects of these toxins on cultured mouse neuroblastoma and fibroblast cells have been evaluated. In both types of cells, submicromolar toxin concentrations rapidly induce striking changes in cell morphology that are reversible upon removal of the toxin. Immunofluorescence studies with antibodies specific for cytoskeletal proteins reveal that the toxins cause major alterations in the organization of microfilaments without obvious effects on the organization of the microtubular system.
Dipetalonema viteae
(Nematoda: Filarioidea): Culture of Third-Stage Larvae to Young Adults in Vitro
Authors: Franke Eileen D. , Weinstein Paul P.
Published: October 2006

Infective third-stage larvae of Dipetalonema viteae (Nematoda: Filarioidea) were cultured to young adults in a cell-free culture system. Third-stage larvae from the tick vector grew, developed, and molted twice in a medium containing NCTC 135 and Iscove's modified Dulbecco's medium supplemented with fetal bovine serum under a gas phase of 95 percent nitrogen and 5 percent carbon dioxide. The availability of such a culture system for filariids should facilitate studies of their immunology, biochemistry, and sensitivity to drugs.
Fetal Brain Transplant: Reduction of Cognitive Deficits in Rats with Frontal Cortex Lesions
Authors: Labbe Randy , Firl Arthur , Mufson Elliott J. , Stein Donald G.
Published: October 2006

Frontal cortex and cerebellar tissue from fetal rats was implanted into the damaged frontal cortex of adults. Cognitive deficits in spatial alternation learning that follow bilateral destruction of medial frontal cortex were reduced in rats with frontal cortex implants but not in those with implants of cerebellum. Histological evaluation showed that connections were made between the frontal cortex implants and host brain tissue.
Light and Propranolol Suppress the Nocturnal Elevation of Serotonin in the Cerebrospinal Fluid of Rhesus Monkeys
Authors: Garrick Nancy A. , Tamarkin Lawrence , Taylor Philip L. , Markey Sanford P. , Murphy Dennis L.
Published: October 2006

Markedly elevated nighttime concentrations of serotonin in rhesus monkey cerebrospinal fluid were reduced to daytime levels by exposing the monkeys to continuous light or to the β-adrenergic antagonist propranolol. Nighttime elevations of melatonin in cerebrospinal fluid were also suppressed by propranolol and light. Serotonin released in large quantities at night appears to be regulated like melatonin, and may act as a cerebroventricular hormone to influence brain and pituitary function at night.
Bioassay of Solubilized
Bacillus thuringiensis
var.
Israelensis
Crystals by Attachment to Latex Beads
Authors: Schnell Danny J. , Pfannenstiel Mary Ann , Nickerson Kenneth W
Published: October 2006

Solubilized crystals of
Bacillus thuringiensis
var.
israelensis
were 7000 times less toxic to
Aedes aegypti
larvae than intact crystals, presumably because mosquito larvae are filter feeders and selectively concentrate particles while excluding water and soluble molecules. A procedure is described whereby soluble toxins are adsorbed to 0.8-micrometer latex beads, with retention of toxicity. The latex bead assay should make it possible to analyze the structure and mode of action of the mosquito toxin.
Association of Parvoviruses with Rheumatoid Arthritis of Humans
Authors: Simpson Robert W. , McGinty Laurel , Simon Lee , Smith Carol A. , Godzeski Carl W. , Boyd Robert J.
Published: October 2006

A small virus resembling parvoviruses in its morphological and physicochemical properties was derived from synovial tissue of a patient with severe rheumatoid arthritis. This virus, designated RA-1, elicits a syndrome in neonatal mice that includes neurological disturbances, permanent crippling of limbs, dwarfism, alopecia, blepharitis, "masking," and a rigid curvature of the thoracic spine. Polyclonal antibodies against RA-1 display high virus neutralizing activity and in immunoassays detect reactive antigen in synovial cells from different rheumatoid arthritis patients but not persons with osteoarthritis. Putative parvoviruses isolated from several other rheumatoid arthritis patients are only weakly pathogenic for newborn mice but can generate RA-1 virus-specific antigens in tissues of these animals. It has not been established that RA-1 and existing parvoviruses of mammalian species are related.
Replication Timing of Genes and Middle Repetitive Sequences
Authors: Goldman Michael A. , Holmquist Gerald P. , Gray Martha C. , Caston Lucetta A. , Nag Abhijit
Published: October 2006

DNA replication in mammals is temporally bimodal. "Housekeeping" genes, which are active in all cells, replicate during the first half of the S phase of cell growth. Tissue-specific genes replicate early in those cells in which they are potentially expressed, and they usually replicate late in tissues in which they are not expressed. Replication during the first half of the S phase is, therefore, a necessary but not sufficient condition for gene transcription. A change in the replication timing of a tissue-specific gene appears to reflect the commitment of that gene to transcriptional competence or to quiescence during ontogeny. Most families of middle repetitive sequences replicate either early or late. These data are consistent with a model in which two functionally distinct genomes coexist in the nucleus.
Influence of Spaceflight on Erythrokinetics in Man
Authors: Leach Carolyn S. , Johnson Philip C.
Published: October 2006

A significant postflight reduction in the circulating red cell mass has been observed in both the American and Soviet manned programs. The mechanism and etiology of this loss were studied in blood samples from the four payload crewmen of Spacelab 1 taken before, during, and after flight. These samples and samples from control groups on the ground were analyzed for selected hematological and biochemical parameters, which were chosen on the basis of data previously collected, the restraints imposed by the use of human subjects, and the guidelines established for the first Spacelab mission. Twenty-two hours after weightless exposure, there was an increase in hemoglobin and hematocrit. On day 7 in flight, the hemoglobin and hematocrit remained high and there was a slight decrease in reticulocyte number. On landing, red cell mass, plasma volume, hematocrit, and reticulocyte number were decreased. Throughout the 2-week postflight sampling period, hemoglobin, hematocrit, and reticulocyte number remained below the preflight value. Since this crew was not exposed to 100 percent oxygen these results are viewed as evidence that other spaceflight factors cause the measured red cell mass reduction.
An Activated
ras
N
Gene: Detected in Late But Not Early Passage Human PA1 Teratocarcinoma Cells
Authors: Tainsky Michael A. , Cooper Colin S. , Giovanella B. C. , Vande Woude George F.
Published: October 2006

Early passages of the human teratocarcinoma cell line PA1 are not tumorigenic in nude mice, while late passages are. A transforming gene present in late passages of PA1 cells was isolated as a biologically active molecular clone and is a new isolate of the human
ras
N
locus. Its transforming activity is due to a single G → A (G, guanine; A, adenine) point mutation at the codon for amino acid 12 which changes the codon for glycine so that an aspartic acid residue is expressed. In contrast to late passage PA1 cells (passages 106, 330, and 338), DNA from the PA1 cell line at early passages (passage 36) does not yield
ras
N
foci in DNA transfection assays. Thus, the presence of an activated
ras
N
in PA1 cells correlates with enhanced tumorigenicity of the cell line and, more importantly, may have arisen during cell culture in vitro.
Need for Reform in Health Professions Accrediting
Authors: Brodie Donald C. , Heaney Robert P.
Published: October 2006

At least 50 vocational or professional groups, exclusive of specialties within categories, now provide a health service. Each group seeks to identify itself as a specialty health service. Many have established accrediting procedures for maintaining educational standards, and the number is increasing. So great is the demand from the accrediting bodies that universities and academic health centers find that the cost in terms of money, time, and duplication of effort has become exhorbitant, and thereby a major problem in the management of educational institutions. The duplication of effort leads to fragmentation of the entire accrediting process, and this, in turn, fosters inadequate sharing of health professions educational experiences. A model is presented that would lessen the burden of accrediting on educational institutions and simultaneously permit testing of the feasibility of a multiprofessional accrediting mechanism.
Terminal Arbors of Axons That Have Formed Abnormal Connections
Authors: Robson John A. , Mason Carol A. , Guillery R. W.
Published: October 2006

The terminal arbors of individual retinogeniculate axons that have been induced to grow into an inappropriate geniculate layer have been revealed for light and electron microscopic study by being filled with horseradish peroxidase. After a unilateral ocular enucleation in kittens, single axons from the surviving eye show terminal arbors not only within their own geniculate layers but also in the denervated layers. The new, abnormal arbors arise from the terminal segments of arbors that lie within the nondenervated layer and make patterns of synaptic contacts that appear normal.
Cytochrome P-450: Localization in Rabbit Lung
Authors: Serabjit-Singh Cosette J. , Wolf C. Roland , Philpot Richard M. , Plopper Charles G.
Published: October 2006

Cytochrome P-450-dependent monooxygenase systems, which metabolize endogenous as well as foreign compounds, are found in hepatic and several extrahepatic tissues of mammals, including humans. A form of cytochrome P-450 is localized in the nonciliated bronchiolar epithelial cells (Clara cells) of the small airways of rabbit lung. The apparent high concentration of the cytochrome in this pulmonary cell type compared to liver may be an important determinant in the susceptibility of the lung to a number of toxic chemicals that undergo metabolic activation.
The Regulation of Carcinogenic Hazards
Authors: Gori Gio Batta
Published: October 2006

In the United States, statutes for controlling carcinogens are largely motivated by the ideal of absolute safety at all costs. There is no requirement for risk-benefit assessment. Bias is inherent in the prescribed bioassays; test findings may have restricted meaning within the specific experiments but cannot be translated into quantitative assessment of human risk. Such data are improperly used in resolving regulatory questions case by case. It is suggested that a system of relative standards of utility be formulated which, paired to standards of tolerable risk or safety, would define a range of use restrictions. Substances intended for a certain use would then be regulated according to those standards.
Limitations of Metabolic Activation Systems Used with in Vitro Tests for Carcinogens
Authors: Bigger C. A. H. , Tomaszewski J. E. , Dipple A. , Lake R. S.
Published: October 2006

Important differences between the metabolic activation of 7,12-dimethylbenz[
a
]anthracene in intact cellular systems and in liver homogenates suggest that the use of homogenates in conjunction with short-term assays for carcinogens could yield misleading results.
Gap Junctional Conductance Is a Simple and Sensitive Function of Intracellular
p
H
Authors: Spray D. C. , Harris A. L. , Bennett M. V. L.
Published: October 2006

The
p
H of the cytoplasm (
p
H
i
) measured with
p
H-sensitive microelectrodes in cleavage-stage blastomeres of amphibian (
Ambystoma
) and teleost (
Fundulus
) embryos is about 7.7. In electrotonically coupled cell pairs, junctional conductance is rapidly and reversibly reduced by acidification of the cytoplasm. The relation between junctional conductance and
p
H
i
is the same for increasing and decreasing
p
H and is independent of the rate of change over a wide range. The relation is well fitted by a Hill curve with K = 50 n
M
(p
K
= 7.3) and
n
= 4 to 5. The closure of gap junction channels at low
p
H
i
appears to be a cooperative process involving several charged sites. The absence of hysteresis and identity of effects for fast and slow
p
H
i
changes implies that protons act directly on the channel macromolecules and not through an intermediate in the cytoplasm.
Neutrophil Activation Monitored by Flow Cytometry: Stimulation by Phorbol Diester Is an All-or-None Event
Authors: Hafeman Dean G. , McConnell Harden M. , Gray Joe W. , Dean Philip N.
Published: October 2006

The population dynamics of single-cell stimulation was analyzed by monitoring autofluorescence by flow cytometry. Stimulation of the respiratory burst in human neutrophils by 12-
O
-tetradecanoyl phorbol-13-acetate (TPA) caused a decline in highly fluorescent cells (characteristic of resting neutrophils) and a corresponding increase in the number of weakly fluorescent cells (characteristic of activated neutrophils). Increasing concentrations of TPA caused increasing numbers of cells to shift from the highly fluorescent population to the weakly fluorescent population without the appearance of intermediate populations. Thus the neutrophil respiratory burst, a component of neutrophil cytotoxic response, is triggered in an all-or none fashion.
Diffusion Coefficients of Respiratory Gases in a Perfluorocarbon Liquid
Authors: O'Brien Robert N. , Langlais Andre, J. , Seufert Wolf D.
Published: October 2006

Although great quantities of respiratory gases dissolve in a perfluorocarbon liquid used to formulate artificial blood, their diffusion rates in this liquid do not exceed those in water.
Tumor Cells Secrete a Vascular Permeability Factor That Promotes Accumulation of Ascites Fluid
Authors: Senger Donald R. , Galli Stephen J. , Dvorak Ann M. , Perruzzi Carole A. , Harvey V. Susan , Dvorak Harold F.
Published: October 2006

Tumor ascites fluids from guinea pigs, hamsters, and mice contain activity that rapidly increases microvascular permeability. Similar activity is also secreted by these tumor cells and a variety of other tumor cell lines in vitro. The permeability-increasing activity purified from either the culture medium or ascites fluid of one tumor, the guinea pig line 10 hepatocarcinoma, is a 34,000- to 42,000-dalton protein distinct from other known permeability factors.