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81.
FB Mochales RB Castelló JC Marqués LD Rodríguez XG Alemany JA Rodríguez EP Beato BP Gorricho EP Trallero GP Pastor 《Canadian Metallurgical Quarterly》1995,69(6):445-461
This document represents the recommendations of a panel of Spanish experts on antibiotic use and resistance. In a Task Force, under the auspices of the Spanish Ministry of Health and Consumer Affairs that took place in 1994 in Madrid, the members were gravely concerned about the national increase in antibiotic resistance. They analysed the development, evolution and spread of antibiotic resistance among community-acquired human bacterial pathogens in Spain, its relation with antibiotic consumption, and they proposed future surveillance strategies for monitoring the patterns of antibiotic use and consumption. Success will require a collective action among the producers (pharmaceutical industry), prescribers (doctors, veterinarians), dispensers (pharmacists), and consumers (patients). Two similar documents have been recently published by the American Society of Microbiology and the World Health Organization showing the global concern about this topic. 相似文献
82.
RE Marc RF Murry SK Fisher KA Linberg GP Lewis M Kalloniatis 《Canadian Metallurgical Quarterly》1998,39(9):1685-1693
PURPOSE: To establish a nomogram of amino acid signatures in normal neurons, glia, and retinal pigment epithelium (RPE) of the cat retina, guided by the premise that micromolecular signatures reflect cellular identity and metabolic integrity. The long-range objective was to provide techniques to detect subtle aberrations in cellular metabolism engendered by model interventions such as focal retinal detachment. METHODS: High-performance immunochemical mapping, image registration, and quantitative pattern recognition were combined to analyze the amino acid contents of virtually all cell types in serial 200-nm sections of normal cat retina. RESULTS: The cellular cohorts of the cat retina formed 14 separable biochemical theme classes. The photoreceptor --> bipolar cell --> ganglion cell pathway was composed of six classes, each possessing a characteristic glutamate signature. Amacrine cells could be grouped into two glycine- and three gamma-aminobutyric acid (GABA)-dominated populations. Horizontal cells possessed a distinctive GABA-rich signature completely separate from that of amacrine cells. A stable taurine-glutamine signature defined Müller cells, and a broad-spectrum aspartate-glutamate-taurine-glutamine signature was present in the normal RPE. CONCLUSIONS: In this study, basic micromolecular signatures were established for cat retina, and multiple metabolic subtypes were identified for each neurochemical class. It was shown that virtually all neuronal space can be accounted for by cells bearing characteristic glutamate, GABA, or glycine signatures. The resultant signature matrix constitutes a nomogram for assessing cellular responses to experimental challenges in disease models. 相似文献
83.
GP Perletti P Concari S Brusaferri E Marras F Piccinini AH Tashjian 《Canadian Metallurgical Quarterly》1998,16(25):3345-3348
We have shown previously that overexpression of the epsilon isoform of protein kinase C (PKCepsilon) in rat colonic epithelial cells causes malignant transformation, possibly by interacting with the ras signal transduction pathway (Oncogene 12: 847, 1996). We have now performed experiments to examine certain early steps in the ras signaling pathway. A marked increase of Raf-1 phosphorylation was detected in tumorigenic ras-transformed D/ras as well as in D/epsilon cells (overexpressing PKCepsilon), compared to the nontumorigenic D/WT parental line. Moreover, in the PKCepsilon-transformed D/epsilon cell line, stable transfection with a dominant-negative raf-1 (DNraf) sequence caused complete regression of the neoplastic phenotype. These results suggested that PKCepsilon-induced transformation was associated with increased Raf-1 activation, and that DNraf could block the oncogenic effect of PKCepsilon. Furthermore, transfection of D/WT cells with dominant-negative ras induced arrest of cell growth, and subsequent transfection with PKCepsilon cDNA enhanced cell proliferation and induced neoplastic transformation. These results suggest that ras acts upstream of PKCepsilon, and that overexpression of PKCepsilon circumvents the block in cell proliferation caused by dominant-negative ras. We conclude that PKCepsilon exerts its oncogenic activity in rat colonic cells by affecting the ras signaling cascade at the level of Raf-1 activation. 相似文献
84.
GP Amarante-Mendes C Naekyung Kim L Liu Y Huang CL Perkins DR Green K Bhalla 《Canadian Metallurgical Quarterly》1998,91(5):1700-1705
Bcr-Abl expression in leukemic cells is known to exert a potent effect against apoptosis due to antileukemic drugs, but its mechanism has not been elucidated. Recent reports have indicated that a variety of apoptotic stimuli cause the preapoptotic mitochondrial release of cytochrome c (cyt c) into cytosol, which mediates the cleavage and activity of caspase-3 involved in the execution of apoptosis. Whether Bcr-Abl exerts its antiapoptotic effect upstream to the cleavage and activation of caspase-3 or acts downstream by blocking the ensuing degradation of substrates resulting in apoptosis, has been the focus of the present studies. In these, we used (1) the human acute myelogenous leukemia (AML) HL-60 cells that are stably transfected with the bcr-abl gene (HL-60/Bcr-Abl) and express p185 Bcr-Abl; and (2) the chronic myelogenous leukemia (CML)-blast crisis K562 cells, which have endogenous expression of p210 Bcr-Abl. Exposure of the control AML HL-60 cells to high-dose Ara-C (HIDAC), etoposide, or sphingoid bases (including C2 ceramide, sphingosine, or sphinganine) caused the accumulation of cyt c in the cytosol, loss of mitochondrial membrane potential (MMP), and increase in the reactive oxygen species (ROS). These preapoptotic events were associated with the cleavage and activity of caspase-3, resulting in the degradation of poly (adenosine diphosphate [ADP]-ribose) polymerase (PARP) and DNA fragmentation factor (DFF), internucleosomal DNA fragmentation, and morphologic features of apoptosis. In contrast, in HL-60/Bcr-Abl and K562 cells, these apoptotic stimuli failed to cause the cytosolic accumulation of cyt c and other associated mitochondrial perturbations, as well as the failure to induce the activation of caspase-3 and apoptosis. While the control HL-60 cells showed high levels of Bcl-2 and barely detectable Bcl-xL, HL-60/Bcr-Abl cells expressed high levels of Bcl-xL and undetectable levels of Bcl-2, a pattern of expression similar to the one in K562 cells. Bax and caspase-3 expressions were not significantly different between HL-60/Bcr-Abl or K562 versus HL-60 cells. These findings indicate that Bcr-Abl expression blocks apoptosis due to diverse apoptotic stimuli upstream by preventing the cytosolic accumulation of cyt c and other preapoptotic mitochondrial perturbations, thereby inhibiting the activation of caspase-3 and execution of apoptosis. 相似文献
85.
We describe ATP-dependent inhibition of the 75-105-pS (in 250 mM Cl-) anion channel (SCl) from the sarcoplasmic reticulum (SR) of rabbit skeletal muscle. In addition to activation by Ca2+ and voltage, inhibition by ATP provides a further mechanism for regulating SCl channel activity in vivo. Inhibition by the nonhydrolyzable ATP analog 5'-adenylylimidodiphosphate (AMP-PNP) ruled out a phosphorylation mechanism. Cytoplasmic ATP (approximately 1 mM) inhibited only when Cl- flowed from cytoplasm to lumen, regardless of membrane voltage. Flux in the opposite direction was not inhibited by 9 mM ATP. Thus ATP causes true, current rectification in SCl channels. Inhibition by cytoplasmic ATP was also voltage dependent, having a K(I) of 0.4-1 mM at -40 mV (Hill coefficient approximately 2), which increased at more negative potentials. Luminal ATP inhibited with a K(I) of approximately 2 mM at +40 mV, and showed no block at negative voltages. Hidden Markov model analysis revealed that ATP inhibition 1) reduced mean open times without altering the maximum channel amplitude, 2) was mediated by a novel, single, voltage-independent closed state (approximately 1 ms), and 3) was much less potent on lower conductance substates than the higher conductance states. Therefore, the SCl channel is unlikely to pass Cl- from cytoplasm to SR lumen in vivo, and balance electrogenic Ca2+ uptake as previously suggested. Possible roles for the SCl channel in the transport of other anions are discussed. 相似文献
86.
Genetic marker technologies, such as marker-assisted selection, parentage identification, and gene introgression can be applied to livestock selection programs. Highly saturated genetic maps are now available for cattle, swine, and sheep to provide the genetic framework for developing MAS programs. These programs rely on three phases for commercialization of the technology: the detection phase, in which quantitative trait loci are located and their effects on the phenotype measured; the evaluation phase, in which the markers are evaluated in commercial populations; and the implementation phase, in which markers are combined with phenotypic and pedigree information in genetic evaluation for predicting the genetic merit of individuals within the population. Predicting the economic impact of genetic technologies is a complex process that requires quantitative prediction and economic analysis. Evaluating the impact of these benefits across an industry can be achieved through a process in which gains from implementation of a genetic technology are assessed at the individual, enterprise, and industry levels. A pattern of annual benefits and costs can be predicted using gene flows that can be evaluated by conventional economic analysis. 相似文献
87.
This paper summarises the findings of a systematic review of research on preschool vision screening. The review concludes that the provision of such screening programmes should be reconsidered, if not abandoned. 相似文献
88.
Hyperthermia has been shown to be an effective radiation sensitizer. Cisplatin has also been shown to cause radiosensitization. In part, the sensitization is through the inhibition of repair of radiation damage. In this study we have set out to combine low dose-rate irradiation (during which extensive repair occurs) with both cisplatin and hyperthermia to maximize the radiation sensitizing effect. Two human ovarian carcinoma cell lines, one parental (A2780S) and the other a cisplatin resistant derivative (A2780CP) cell line were used in these experiments. Long duration hyperthermia at 40 degrees C was combined with low concentrations of cisplatin (0.5-3 microg/ml) and low dose-rate irradiation (LDRI). The responses to the individual treatments showed that there was cross resistance in the two cell lines for cisplatin and radiation, but for hyperthermia the opposite effect was found. When all treatments were given concurrently the response was greater than the calculated response of all three individual treatments, indicating a synergistic interaction. The effect was greater in the cisplatin resistant cell line. The combination of mild hyperthermia, low dose cisplatin and LDRI are a good combination for potential clinical application. In addition, this could be a good approach to deal with cisplatin resistance. 相似文献
89.
D Liveris GP Wormser J Nowakowski R Nadelman S Bittker D Cooper S Varde FH Moy G Forseter CS Pavia I Schwartz 《Canadian Metallurgical Quarterly》1996,34(5):1306-1309
Ninety-three Borrelia burgdorferi isolates obtained from erythema migrans lesions or blood of Lyme disease patients in Westchester County, N.Y., between 1991 and 1994 were characterized by PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of the 16S-23S rRNA gene spacer. All isolates could be classified into three distinct RFLP types. Among the 82 skin biopsy isolates studied, 21 (25.6%) were type 1, 37 (45.1%) were type 2, and 21 (25.6%) were type 3. Three (3.7%) cultures contained a mixture of two isolates with distinct RFLP types. The 11 isolates cultured from blood showed a similar predominance of RFLP type 2 (6 of 11; 54.5%) relative to types 1 (2 of 11; 18.2%) and 3 (3 of 11; 27.3%). For one patient both skin and blood isolates were cultured, and RFLP analysis revealed that these isolates differed from one another. This study demonstrates that there is genotypic heterogeneity in B. burgdorferi strains infecting Lyme disease patients, and this typing approach may allow differentiation of isolates with various degrees of pathogenic potential. 相似文献
90.
AIM: To report the quantitation of the lipid composition of a corneal button from a Japanese woman in her 60s with clinically and histopathologically proved Schnyder's corneal dystrophy. METHODS: Total lipids extracted from the corneal button of the patient were analysed by the method of thin layer chromatography flame ionisation detection. Two different solvent systems were used for neutral lipid analysis and phospholipid analysis. Results were compared with three age matched corneal buttons obtained from cadaveric eyes. RESULTS: The lipids that accumulated in the cornea in Schnyder's dystrophy consisted mainly of unesterified cholesterol and phospholipids. The analysis of phospholipids showed sphingomyelin to be the predominant phospholipid in the patient's cornea. CONCLUSION: Findings suggest that this disorder involves a disturbance of the metabolism of cholesterol and/or sphingomyelin metabolism that is limited to the cornea. 相似文献