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  • ASTROPHYSICS  (154)
  • Life and Medical Sciences  (126)
  • Humans  (92)
  • Lunar and Planetary Science and Exploration
  • 2015-2019
  • 1985-1989  (373)
  • 1987  (373)
  • 1
    Publication Date: 1987-10-30
    Description: The possibility that Alzheimer's disease (AD) is caused by overexpression or duplication of one or more genes on chromosome 21 has been raised by the observation of AD-like neuropathologic changes in individuals with Down syndrome and by the mapping of both the defect for familial AD and the amyloid beta protein gene to this autosome. Possible duplication on chromosome 21 was investigated in both familial and sporadic AD by means of restriction fragment length polymorphisms for the amyloid and SODI loci, as well as for DNA markers in the vicinity of the familial AD defect and in the critical Down syndrome region of chromosome 21. No evidence of increased DNA dosage was observed in either brain or leukocytes of patients with inherited or sporadic forms of AD. Duplication of these regions is therefore not a frequent event in either form of AD. Furthermore, no significant allelic association was detected between AD and any of the loci, including the amyloid and SODI genes, providing no support for the hypothesis that defects in these specific genes are the primary cause of AD.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉St George-Hyslop, P H -- Tanzi, R E -- Polinsky, R J -- Neve, R L -- Pollen, D -- Drachman, D -- Growdon, J -- Cupples, L A -- Nee, L -- Myers, R H -- ADRC P50 AGO5134-02/AD/ADAMHA HHS/ -- NS20012/NS/NINDS NIH HHS/ -- R01 AGO6865-1/AG/NIA NIH HHS/ -- New York, N.Y. -- Science. 1987 Oct 30;238(4827):664-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Neurogenetics Laboratory, Massachusetts General Hospital, Boston.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2890206" target="_blank"〉PubMed〈/a〉
    Keywords: Alleles ; Alzheimer Disease/*genetics ; Amyloid/genetics ; *Chromosomes, Human, Pair 21 ; Genes ; Genetic Linkage ; Humans ; Polymorphism, Restriction Fragment Length
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 2
    Publication Date: 1987-07-17
    Description: New blood vessel growth occurs during normal fetal development and in diseases such as cancer and diabetes. The polypeptide angiogenin induces new blood vessel growth in two biological assays and may play a role in the vascular development of the fetus and in the neovascularization that accompanies diseases and wound healing. A complementary DNA probe for human angiogenin was used to examine the tissue distribution of angiogenin messenger RNA (mRNA) in the developing rat and in selected transformed cell lines. Angiogenin mRNA was detected predominantly in adult liver but was also detectable at low levels in other tissues. The expression of the angiogenin gene in rat liver was found to be developmentally regulated; mRNA levels were low in the developing fetus, increased in the neonate, and maximal in the adult. The amount of angiogenin mRNA in human HT-29 colon carcinoma and SK-HEP hepatoma cells was not greater than that in normal rat liver. These results demonstrate that angiogenin is predominantly expressed in adult liver, that the pattern of angiogenin gene expression is not temporally related to vascular development in the rat, and that the transformed cells studied do not contain more angiogenin mRNA than does normal liver. If angiogenin activity is controlled at the transcriptional level, the results of this study suggest that the primary function of angiogenin in vivo may be in processes other than the regulation of vascular growth.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weiner, H L -- Weiner, L H -- Swain, J L -- HL26831/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1987 Jul 17;237(4812):280-2.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2440105" target="_blank"〉PubMed〈/a〉
    Keywords: Age Factors ; Animals ; Cell Line ; Gene Expression Regulation ; Humans ; Liver/physiology ; Neoplasm Proteins/*genetics ; Neovascularization, Pathologic ; RNA, Messenger/genetics ; Rats ; *Ribonuclease, Pancreatic ; Tissue Distribution
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 6 (1987), S. 204-208 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tumor-cell diversification mechanisms insure that malignant neoplasms contain diversified tumor-cell subpopulations. Because of the instability of tumor cell phenotypes, some malignant cells will evolve with the most favorable properties for their progression to highly metastatic cells. The rates of cellular phenotypic diversification vary greatly among different tumors, and they are probably modulated, in part, by genetic and chromosome defects and by epigenetic events that may vary widely depending upon the nature of the tumor cells and their microenvironments. As tumor diversification and selection proceed, the most malignant cell subpopulations may eventually become dominant and gradually lose their microenvironmental responsiveness. Tumor-cell diversification mechanisms may be similar or identical to normal, developmentally regulated diversification mechanisms that are used during embryonic cell diversification and differentiation.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 8 (1987), S. 337-350 
    ISSN: 0197-8462
    Keywords: hair vibration ; extremely low frequencies ; chronic stimulation ; exposure system ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Chronic exposure of animals to 60-Hz electric fields is known to affect the nervous system in a variety of subtle ways. The mechanism whereby these effects are produced remains unknown. One hypothesis is that the effects are a result of direct interaction between neuronal membranes and induced currents. Alternatively, the effects could be produced indirectly, as a result of sensory stimulation and the resulting low-level stress. To test these hypotheses, a system was developed to expose the surface of an anesthetized cat's paw to surface electric fields up to 600 kV/m while simultaneously measuring, in dorsal root fibers, afferent nerve impulses originating from various receptor types in the exposed paw. Of the 245 receptor units tested, comprising ten cutaneous receptor types, ten responded to the electric field with an increase in firing rate. The most sensitive receptor type was the rapidly adapting field receptor (RAF); eight of 20 (40%) were sensitive to the electric field, with thresholds as low as 160 kV/m. One of 35 rapidly adapting high-frequency receptors and one of 22 type T hair-follicle receptors were also sensitive to the electric field. Follow-up tests on the RAF receptors showed that hair removal reduced but did not eliminate the electric field sensitivity, suggesting that at least one other mechanism was involved in addition to stimulation via hair movement. The most likely mechanism is field-induced vibrations of the skin, since a further reduction in firing rate occurred following application of mineral oil to the depilated paw. Direct interaction with neuronal membranes is not supported by our evidence.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 8 (1987), S. 229-242 
    ISSN: 0197-8462
    Keywords: reproduction ; teratology ; embryotoxicity ; growth ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Evaluations of reproductive and developmental toxicology, including teratology, were included as part of a broad screening study in Hanford Miniature swine (HMS) to detect effects of exposure to electric fields. One group (E) was exposed to a uniform, vertical, 60-Hz, 30-kV/m electric field for 20 h/day, 7 days/week sham-exposed (SE) swine were housed in a separate, environmentally equivalent building. The first generation (F0) gilts were bred after 4 months of study; some were killed for teratologic assays at 100 days of gestation (dg), and the others produced an F1 generation of offspring. The pooled incidence of terata in these litters (teratologic assays and live births) was similar in the E and SE groups. The F0 females, which produced the F1 generation, were bred again after 18 months of exposure and were killed at 100 dg. Malformation incidence in E litters (75%) was significantly greater than in SE litters (29%). No consistent differences in litter size, fetal mass, or mass of fetal organs were detected. The F1 gilts were bred at 18 months of age; defective offspring were found in significantly more of the E litters (71 %) than in SE litters (33%). These F1 females were bred again 10 months later and teratologic assays were performed on their second litters at 100 dg. The percentage of litters with malformed fetuses was essentially identical in the E and SE groups (70% and 73%, respectively). There appears to be an association between chronic exposure to a strong electric field and developmental effects in swine, although the change in incidence of malformations between generations and between the first and second breedings makes it impossible to conclude unequivocally that there is a cause-and-effect relation.
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  • 6
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gross and microscopic examination of the lingual appendages of juvenile and adult alligator snapping turtles, Macroclemys temmincki, shows that it is divided into an anterior horn, a body, and a posterior horn. Lingual appendages of adults usually are more darkly pigmented than those of juveniles and melanocyte distribution is variable, resulting in a mottled appearance. The musculoskeletal components of the hyoid apparatus, presumably responsible for most of the motion displayed by the appendage, are described here. The lingual appendage is innervated by the lingual nerve which divides into three branches, two coursing rostrally into the anterior horn and one running caudally into the posterior horn. These branches ramify and end in numerous terminals within the lamina epithelialis and lamina propria. The lamina epithelialis of the distal three-fourths of the horns of the lingual appendage contain structures similar to taste buds described in other species of turtles. Goblet cells, containing acid mucopolysaccharides, are located in the stratified squamous epithelium. Blood is transported to the appendage via the lingual artery, which is a terminal branch of the external carotid artery. Numerous venous sinuses lie among the predominant bundles of connective tissue and account for approximately one-fifth of the total volume of the appendage. An engorged appendage is swollen and pinker in color.The coloration, enlargement, and wiggling movement combined with its buoyancy in water make the appendage imitate a small worm or an insect larva. The increase in melanin during ontogeny may produce a more variable pattern and may increase the number of organisms attracted by the appendage. The acid mucopolysaccharides of the globlet cells presumably may condition the nonkeratinized, stratified squamous epithelial surface of the appendage. The flexibility of the pseudoerect, active appendage keep it from being injured.
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  • 7
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In contrast to most tissues, epidermis and its derivatives appear to lack low density lipoprotein (LDL) receptors and exhibit sterologenesis rates unaffected by circulating lipoprotein (LP) cholesterol content. Since LDL receptors have been demonstrated in both cultured squamous cell carcinoma cells and human foreskin keratinocytes, when maintained in low-calcium media, LDL receptor expression may be related to keratinocyte differentiation. We compared receptor binding and internalization of LDL-gold in normal keratinocytes at different stages of growth at physiological calcium concentrations (early, 3-5 days; preconfluent, 6-10 days; postconfluent, 12-17 days), and correlated receptor expression with sterologenesis in LP-replete vs.-depleted media. Whereas in early cultures about 60% of sterologenesis was LP dependent, this fraction declined in preconfluent and confluent cultures despite continued culture growth and little decline in total sterologenesis. Accordingly, LDL receptors were most evident in early cultures, declining in preconfluent cultures in parallel with the decrease in LP-dependent sterol synthesis. In contrast, sterologenesis in human foreskin fibroblasts was profoundly influenced by exogenous LP at all stages of confluence; total and LP-dependent sterologenesis declined in parallel with growth cessation. These studies represent the first demonstration that normal keratinocytes express functional LDL receptors at physiologic calcium concentrations. Moreover, they demonstrate that LDL receptor expression in keratinocytes, in contrast to fibroblasts, can only in part be attributed to growth requirements. Instead, loss of LDL receptor expression serves as a distinctive marker of keratinocyte differentiation and may reflect the specific functional requirements of the epidermis in vivo.
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  • 8
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Utilizing a digitonin-permeabilized cell system, we have studied the release of calcium from a non-mitochondrial intracellular compartment in cultured human fibroblasts (HSWP cells). Addition of 1 mM MgATP to a monolayer of permeabilized cells in a cytosolic media buffered to 150 nM Ca with EGTA rapidly stimulates 45Ca uptake, and the subsequent addition of the putative intracellular messenger inositol trisphosphate (InsP3) induces rapid release of 85% (±6% n = 6) of the 45Ca taken up in response to ATP. Mitogenic peptides (bradykinin, vasopressin, epidermal growth factor [EGF], and insulin) and orthovanadate, which are effective in mobilizing intracellular Ca in intact cells, have little or no effect when added alone to permeabilized cells. However, in the presence of GTP these agents stimulate accumulation of inositol phosphates and release Ca from the InsP3-sensitive pool. These data suggest that a GTP binding protein is involved in receptor mediated activation of phospholipase C, which leads to release of inositol phosphates. The GTP-dependent release of InsP3 and the mobilization of 45Ca from the intracellular compartment are inhibited by pretreatment of cells, prior to permeabilization, with the protrein kinase C activator 12-O-tetradecanoyl-phorbol-13-acetate (TPA). TPA pretreatment does not affect the InsP3 stimulated Ca release. These results suggest that protein kinase C is involved in down-regulation or inhibition of phospholipase C, or the GTP binding protein responsible for relaying the mitogenic signal from the cell surface receptor to the phospholipase C activity.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 130 (1987), S. 103-110 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of amino acid depletion or supplementation and the effect of glucagon and insulin on the amino acid transport mediated by system A were investigated by determining the uptake of either 2-amino [1-14C]isobutyric acid (AIB) or N-methyl 2-amino [1-14C]isobutyric acid (MeAIB) in rat hepatocytes, freshly isolated at different stages of pre- and postnatal development. The data obtained show that the Na+-dependent uptake was higher at the earliest developmental stages, and steadily decreased until the adult level. The hormones increased AIB and MeAIB uptake enhancing the Vmax, while the Km was unchanged. This effect was evident in cells from adult and 18-20-day-old fetuses, while no response was present before the 18th day of fetal life and in the perinatal period. Actinomycin D or cycloheximide abolished this hormone-dependent increase. A decrease in AIB and MeAIB transport after incubation in an amino acid-rich medium was demonstrated at all ages tested, but was particularly evident in the prenatal life. The increase in the activity of the system following amino acid starvation was shown to be mostly dependent from de novo protein synthesis in the fetal life; on the contrary in the adult the increase appeared to be more linked to the releas from transinhibition of the transport.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 132 (1987), S. 178-182 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Verapamil inhibited Na+-dependent uptake of serotonin (5-HT) by bovine pulmonary artery endothelial cells in culture both exposed to room air and stimulated by prior exposure to anoxia. The effect of verapamil occurred even in the absence of Ca2+ from the assay medium. Although absence of Ca2+ from the medium moderately reduced 5-HT uptake, stimulation of uptake was nevertheless observed for cells previously exposed to anoxia. Verapamil altered the Km, but not the Vmax, of 5-HT uptake. There was no change in 45Ca2+ uptake or release by cells previously exposed to anoxia as compared to those exposed to room air and verapamil did not influence 45Ca2+ fluxes by either set of cells. It is concluded that verapamil inhibits 5-HT uptake by endothelial cells through a mechanism other than Ca2+ channel blockade; the results are consistent with competitive inhibition of a 5-HT carrier. The stimulatory effect of anoxia on 5-HT uptake does not occur through a change in Ca2+ fluxes.
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