Irish consultants' attitudes towards the climate of increasing medical litigation in Ireland.
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Attitude of Health Personnel↗
Biomedical subjects
E Long
Publications and source records attributed to E Long.
Lactation persistency: insights from mammary cell proliferation studies.
A persistent lactation is dependent on maintaining the number and activity of milk secreting cells with advancing lactation. When dairy cows are milked twice daily, the increase in milk yield from parturition to peak lactation is due to increased secretory activity per cell rather than to accretion of additional epithelial cells. After peak lactation, declining milk yield is due to loss of mammary epithelial cells by apoptosis. During lactation, only 0.3% of mammary cells proliferate in a 24-h period. Yet this proliferative rate is sufficient to replace most mammary epithelial cells by the end of lactation. Management practices can influence lactation persistency. Administration of bovine somatotropin may enhance persistency by increasing cell proliferation and turnover, or by reducing the rate of apoptosis. Increased photoperiod may also increase persistency of lactation by mechanisms that are as yet undefined. Increased milking frequency during the first weeks of lactation increases milk yield, even after return to less frequent milking, with increases of approximately 8% over the entire lactation. A mammary cell proliferation response to frequent milking during early lactation appears to be involved. Conversely, advanced pregnancy, infrequent milking, and mastitis increase death of epithelial cells by apoptosis. Regulation of mammary cell renewal provides a key to increasing persistency. Investigations to characterize epithelial cells that serve as the proliferative population in the bovine mammary gland have been initiated. Epithelial cells that stain lightly in histological sections are evident through all phases of mammary development and secretion and account for nearly all proliferation in the prepubertal gland. Characterization of these cells may provide a means to regulate mammary cell proliferation and thus to enhance persistency, reduce the effects of mastitis, and decrease the necessity for a dry period.
Animals↗
A peripheral mechanism for behavioral adaptation to specific "bitter" taste stimuli in an insect.
Animals have evolved several chemosensory systems for detecting potentially dangerous foods in the environment. Activation of specific sensory cells within these chemosensory systems usually elicits an aversive behavioral response, leading to avoidance of the noxious foods. Although this aversive behavioral response can be adaptive, there are many instances in which it generates "false alarms," causing animals to reject harmless foods. To minimize the number of false alarms, animals have evolved a variety of physiological mechanisms for selectively adapting their aversive behavioral response to harmless noxious compounds. We examined the mechanisms underlying exposure-induced adaptation to specific "bitter" compounds in Manduca sexta caterpillars. M. sexta exhibits an aversive behavioral response to many plant-derived compounds that taste bitter to humans, including caffeine and aristolochic acid. This aversive behavioral response is mediated by three pairs of bitter-sensitive taste cells: one responds vigorously to aristolochic acid alone, and the other two respond vigorously to both caffeine and aristolochic acid. We found that 24 hr of exposure to a caffeinated diet desensitized all of the caffeine-responsive taste cells to caffeine but not to aristolochic acid. In addition, we found that dietary exposure to caffeine adapted the aversive behavioral response of the caterpillar to caffeine, but not to aristolochic acid. We propose that the adapted aversive response to caffeine was mediated directly by the desensitized taste cells and that the adapted aversive response did not generalize to aristolochic acid because the signaling pathway for this compound was insulated from that for caffeine.
Adaptation, Physiological↗
Overexpressing eukaryotic translation initiation factor 4E stimulates bovine mammary epithelial cell proliferation.
BACKGROUND AND AIMS: The eukaryotic translation initiation factor 4E regulates the proliferation of many cell types. In the present study, the effect of its overexpression on the growth of an immortalized bovine mammary epithelial cell line, MAC-T, has been investigated. Since involvement of cyclin D1 in growth regulation of other cell types has been suggested previously, the differences in cyclin D1 expression among the 4E-overexpressing and parental cells were also investigated. METHODS: The cDNA of mouse eukaryotic translation initiation factor 4E coding region (either wild-type or mutant, where Trp-56 was mutated to Ala) was transfected into MAC-T cells, and its protein expression was detected by Western blot analysis. Growth rates and saturation densities were calculated based on the cell counting data at desired time points. KEY RESULTS: The cells overexpressing wild-type 4E displayed higher growth rates and saturation densities compared to the parental cells (P<0.05), whereas cells expressing mutant 4E showed lower growth rates and saturation densities than the parental controls (P<0.05). The amounts of cyclin D1 mRNA and protein were higher in the wild-type transfectants than in the parental controls, whereas the mutant transfectants contained lower amounts of cyclin D1 mRNA and protein compared to the parental cells. CONCLUSION: Our results suggest that overexpression of eukaryotic translation initiation factor 4E leads to increased cyclin D1 expression at the transcriptional level, which consequently stimulates the proliferation of MAC-T cells.
Animals↗
Escherichia coli induces apoptosis and proliferation of mammary cells.
Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection. The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection. Induction of matrix metalloproteinase-9, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue. These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation.
Animals↗
Selective adaptation to noxious foods by a herbivorous insect.
When animals repeatedly sample a noxious food over a period of 1-4 days, they can markedly reduce their aversive behavioral response to the diet's unpleasant taste (e.g. 'bitterness') or toxic effects. This long-term adaptation process is selective, however, permitting insects to adapt physiologically to some but not all noxious foods. We hypothesized (i) that the selective nature of this adaptation process stems from the fact that some unpalatable foods are toxic while others are harmless and (ii) that insects have more difficulty adapting to foods that are both unpalatable and toxic. Our model system consisted of Manduca sexta caterpillars and two compounds that taste bitter to humans and elicit an aversive behavioral response in this insect (salicin and aristolochic acid). We found that 2 days of exposure to a salicin diet completely adapted the aversive response of the caterpillars to salicin, but that exposure to an aristolochic acid diet failed to adapt the aversive response to aristolochic acid. We determined that M. sexta could not adapt to the aristolochic acid diet because it lacked mechanisms for reducing the compound's toxicity. In contrast, the salicin diet did not produce any apparent toxic effects, and the caterpillars adapted to its aversive taste within 12 h of exposure. We also found that the salicin adaptation phenomenon (i) was mediated by the central gustatory system, (ii) generalized to salicin concentrations that were twice those in the adapting diet and (iii) offset spontaneously when the caterpillar was transferred to a salicin-free diet. We propose that toxicity is a more significant barrier to dietary adaptation than 'bitterness' in this insect.
Adaptation, Physiological↗
Cloning of bovine eukaryotic translation initiation factor 4E (eIF-4E) and its expression in the bovine mammary gland at different physiological stages.
Bovine eIF-4E cDNA was cloned and its expression in the bovine mammary gland at distinct physiological stages was investigated. Bovine eIF-4E cDNA and protein sequences are highly homologous to those from other mammals. Using Northern blot analysis, we did not detect eIF-4E expression in the prepubertal bovine mammary gland, whereas a low level of eIF-4E mRNA was observed in the mammary tissues of heifers during the third estrous cycle. The eIF-4E mRNA level was significantly higher in the lactating mammary gland compared to the mammary tissues obtained from heifers during the third estrous cycle. Alteration of eIF-4E expression in bovine mammary tissues during different physiological stages indicates the involvement of eIF-4E in mammary development. Elevated eIF-4E expression during lactation may be related to increased translation of certain mRNA or the acceleration of overall protein synthesis.
Amino Acid Sequence↗
A Japanese logographic character frequency list for cognitive science research.
This paper describes a Japanese logographic character (kanji) frequency list, which is based on an analysis of the largest recently available corpus of Japanese words and characters. This corpus comprised a full year of morning and evening editions of a major newspaper, containing more than 23 million kanji characters and more than 4,000 different kanji characters. This paper lists the 3,000 most frequent kanji characters, as well as an analysis of kanji usage and correlations between the present list and previous Japanese frequency lists. The authors believe that the present list will help researchers more accurately and efficiently control the selection of kanji characters in cognitive science research and interpret related psycholinguistic data.
Cognitive Science↗
Dependence of superoxide anion production on extracellular and intracellular calcium ions and protein kinase C in PMA-stimulated bovine neutrophils.
The involvement of both intracellular and extracellular calcium, as well as the activation of protein kinase C (PKC), in phorbol myristate acetate (PMA)-stimulated respiratory burst in bovine neutrophils has been studied. PMA significantly stimulated the superoxide anion production by these cells. The increased production of superoxide anion was inhibited by BAPTA/AM, an intracellular calcium ([Ca2+]i) chelator, but not affected by EGTA, an extracellular calcium ([Ca2+]0) chelator. PMA also induced PKC activation, and a PKC inhibitor, calphostin C, blocked the stimulatory effect of PMA on superoxide anion production by the neutrophils. Therefore, we conclude that PMA-induced respiratory burst in bovine neutrophils is [Ca2+]i- but not [Ca2+]0-dependent, and also requires PKC activation.
Animals↗
Use of systematic reviews of randomised trials by Australian neonatologists and obstetricians.
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Australia↗
Involvement of insulin-like growth factor-1 and its binding proteins in proliferation and differentiation of murine bone marrow-derived macrophage precursors.
Insulin-like growth factor 1 (IGF-1) and its binding proteins (IGFBPs) are involved in proliferation and differentiation of many cell types. In the present study, the involvement of IGF-1 and IGFBPs in proliferation and differentiation of murine bone marrow-derived macrophages (BMDM) was investigated. L929-conditioned media (LCM) containing abundant macrophage colony-stimulating factor CSF-1 were used to stimulate BMDM development from their bone marrow precursors. The alteration of IGF-1 and IGFBPs during LCM-induced BMDM proliferation and differentiation was first studied. The cells were cultured in RPMI complete media containing 20% LCM for different time periods and then incubated in serum-free media for 24 h. The supernatants were collected for Western ligand blotting and immunoblotting analyses, and the cell pellets for Northern blotting analyses. The mRNA level of IGF-1 increased in a time-dependent manner. An increase of IGFBP-4 accumulation in the conditioned media was also observed during this process. However the mRNA expression of IGFBP-4 remained constant, indicating a posttranscriptional regulation of IGFBP-4 secretion and/or stability. The effects of exogenous recombinant human IGF-1 (rhIGF-1) on BMDM proliferation and differentiation were further studied. Two IGF-1 analogs (long R3 IGF-1 and des [1-3] IGF-1) were also used in parallel with regular IGF-1 to indicate the involvement of IGFBPs in BMDM development. Cells were cultured in complete media containing 20% LCM for different time periods, and then incubated in serum-free media in the presence of rhIGF-1 or its analogs for 24 h. These three forms of IGF-1 all potentiated the proliferation of freshly isolated BMDM precursors (d 0). rhIGF-1 and long R3 IGF-1, but not des (1-3) IGF-1, continued to stimulate the cell proliferation on d 1. The effects of these three forms of IGF-1 on BMDM differentiation were investigated using mannose receptor expression as a marker. Long R3 IGF-1 and des (1-3) IGF-1, but not rhIGF-1, enhanced BMDM differentiation on d 4. The different effects of rhIGF-1 and its analogs on BMDM differentiation suggest that the accumulation of IGFBP-4 in BMDM development might have an inhibitory effect on IGF-1 actions by sequestering free IGF-1.
Animals↗
Breast cancer in African-American women. Review of the literature.
Decreased survival rates from breast cancer in the poor and in many African-American women are pressing public health problems. Health care providers are challenged to reduce breast cancer deaths in high-risk poor and African-American populations to achieve the National Cancer Institute's goal of reducing cancer deaths 50% by the year 2000. This article presents findings from a review of the literature concerning (a) the disproportionate distribution of cancer deaths in poor and African-American populations compared with non-poor white populations; (b) breast cancer detection initiatives and barriers to health services utilization; (c) primary prevention of breast cancer; and (d) broad strategies to empower poor and African-American women better to control their destiny through enhanced health practices and public policy initiatives.
Adult↗
Dowling-Degos disease and Kitamura's reticulate acropigmentation: support for the concept of a single disease.
Dowling-Degos disease and Kitamura's reticulate acropigmentation are both rare disorders of pigmentation, which predominantly affect the flexures and the extremities, respectively. A small number of patients with features of both disorders have been described, suggesting that these clinical patterns may be different manifestations of the same disease. We present a further case to support this conclusion.
Axilla↗
Cell surface expression of hybrid murine/human MHC class II beta alpha dimers. Key influence of residues in the amino-terminal portion of the beta 1 domain.
To aid in the identification of key residues responsible for the control of class II MHC beta-alpha dimer assembly and expression, a series of cotransfections of human plus mouse beta- and alpha-genes was performed. The resulting expression data were correlated with the sequences of the relevant proteins to identify residues that played critical roles in these processes. For the I-E/DR homologues good expression was seen for both E beta DR alpha and DR beta E alpha combinations involving several allelically variable beta-chains of each species. These results are consistent with the sequence conservation seen for I-E and DR gene products, and indicate that the species-specific differences that do exist play little role in controlling dimer formation or transport. For A beta chains, a more complex picture was seen. A beta d, but not A beta k or A beta b, was found to coexpress with human alpha-chains. Not only did A beta d show expression with the homologous DQ alpha-chain, but it also was expressed with DR alpha and DP alpha. These data indicate that species-specific residues do not control dimer expression under these conditions and confirm that allelically polymorphic residues have a crucial role in this process. Mapping studies using recombinant A beta genes established the importance of the residues in the amino-terminal half of the beta 1 domain in the differences observed among the A beta alleles. Sequence comparison of DR beta, DP beta, DQ beta, E beta, and A beta chains in this region revealed a single residue (position 12) conserved in most chains and differing in a nonconservative fashion between A beta d vs A beta b or k. A beta d has the conserved lysine at this position, whereas A beta b has methionine and A beta k has glutamine. To test whether this residue actually was important physiologically, a lysine codon was created in a recombinant A beta gene possessing the amino-terminal sequence of the kappa haplotype, and the ability of this mutant chain to be expressed with various mouse A alpha-chains was examined. This mutant chain was shown to gain the ability to be efficiently expressed with A alpha d without losing its ability to be expressed with A alpha k. These data reemphasize the special role played by allelically polymorphic residues in Ia expression and identify one such polymorphic site as position 12.(ABSTRACT TRUNCATED AT 400 WORDS)
Alleles↗
AIDS victims and heterosexual attitudes.
This study reports on the development of a Likert scale that measures attitudes toward AIDS victims (ATAV) in five phases. A total of 582 undergraduate (means age = 24.2) completed the survey forms, 249 males and 333 females. The results for Phase 1 yielded a scale with high part-whole correlations (.62-.90, p less than .001), corrected split-half reliability (.87, p less than .001), and alpha coefficients (.91, p less than .001). The following phases yielded significant correlations between the ATAV scale and attitudes toward homosexuals (.60, p less than .001), homosexual parenting (.64, p less than .001), other minority groups (.33, .37, p less than .001), capital punishment (-.27 p less than .001), and sexually liberal attitudes (.22, .37, .23, p, less than .025). Attitudes toward homosexuals are the central component in attitudes toward AIDS victims. A varimax rotated factor analysis of the ATAV yielded one primary factor accounting for 85.9% of the variance.
Acquired Immunodeficiency Syndrome↗
Dry chemistry thin film immunoassay.
The authors report the development of a novel thin film multilayer immunoassay technology. The technology is applied to therapeutic drug monitoring and thyroid hormone testing in serum or plasma and can be extended to assays of other low molecular weight analytes. The assay detection range spans five orders of magnitude, from 1 x 10(-3) to 1 x 10(-8) M. The assay element comprises of multilayer coated chip, containing the active reagents in an agarose matrix and a plastic module serving both as a holder and a spreader. The assays are in the fluorescent competitive immunoassay format of the ligand displacement mode and are performed on an automated instrument with random access capability. The assays are fast and reliable and gave very good agreement when compared to reference methods.
Immunoassay↗
Comparison of MHC genes among distantly related members of the genus Mus.
The genomic content of class I and class II MHC DNA sequences in a variety of wild mice has been analyzed. The panel of mice includes members of three subgenera of the genus Mus. By genomic hybridization with the use of a variety of DNA probes, both class I and class II DNA sequences appear to be conserved in all of the species examined. However, the number of class I DNA sequences differs among the species. Furthermore, this variation appears to result from differential increases within subsets of class I genes. These data suggest that the class I multigene family is dynamic and changing over short periods of evolutionary time. In contrast, none of the class II genes appears to vary in copy number. More extensive polymorphism was noted amongst the class II beta genes than the alpha genes. Interestingly, the genomic sequence corresponding to E beta 2 is highly conserved, leading to the prediction that it is a genetically functional sequence.
Animals↗
Molecular organization of the HLA-SB region of the human major histocompatibility complex and evidence for two SB beta-chain genes.
The class II products of the major histocompatibility complex, also called Ia antigens, are composed of two polypeptide chains, the alpha and beta chains, both encoded within the major histocompatibility complex. In man, the class II antigens can be divided into three biochemically distinct groups called HLA-DR, HLA-DC, and HLA-SB. Our isolation of cDNA clones for the polymorphic beta chain of HLA-DR and HLA-DC has allowed us to study the organization of the class II genes. Here we identify the HLA-SB beta-chain gene in recombinant clones from a cosmid library generated from a consanguineous homozygous B-cell line. The SB beta-chain gene is linked to the SB alpha-chain gene and the two genes are in opposite orientation. A second SB beta-chain gene, corresponding to a new SB beta II locus, has also been identified and cloned. The SB beta-chain genes show much less allelic restriction site polymorphism than the genes for the beta chains of HLA-DR or HLA-DC.
Amino Acid Sequence↗