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81.
The most common cause of illness in infancy and childhood is acute infection of the respiratory tract. Several recent studies have reported that life-threatening respiratory disease in infancy, such as pneumonia and bronchiolitis, is directly related to the smoking habits of parents. The effects of smoking are more hazardous to youngsters because babies and young children breathe more rapidly than adults. Because of this higher breathing rate, they inhale more air—and more pollution—in comparison to their total body weight. The harmful effects of cigarette smoking on infants and children and recommendations for specific interventions to minimize or eliminate this health hazard are discussed. 相似文献
82.
David Hirschwerk Christine C Ginocchio Maureen Bythrow Susan Condon 《Infection control and hospital epidemiology》2006,27(3):315-317
We cared for a patient with methicillin-resistant Staphylococcus aureus bacteremia who experienced clinical failure with daptomycin. The failure was accompanied by progressive elevation of the daptomycin minimum inhibitory concentration during treatment. DNA fingerprinting confirmed that the minimum inhibitory concentration elevation occurred within the same strain of methicillin-resistant Staphylococcus aureus. This observation provides important new information to clinicians who adopt this promising drug for treatment of serious infections caused by methicillin-resistant Staphylococcus aureus. 相似文献
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86.
Survival, mutagenesis, and host cell reactivation in a Chinese hamster ovary cell ERCC1 knock-out mutant 总被引:2,自引:0,他引:2
Rolig Rhonda L.; Layher Susan K.; Santi Barbara; Adair Gerald M.; Gu Feng; Rainbow Andrew J.; Nairn Rodney S. 《Mutagenesis》1997,12(4):277-283
Positive selection-negative selection gene targeting was usedto disrupt the nucleotide excision repair gene ERCC1 in a Chinesehamster ovary cell line, CHO-K1. Southern and Northern analysisshowed that a cell clone isolated by this targeting approach,CHO-7-27, had an ERCC1 gene structure consistent with targeteddisruption of ERCC1 exon V, and did not express ERCC1 mRNA.CHO-7-27 was further characterized with respect to UV and mitomycinC sensitivities, and was shown to exhibit severe mutagen sensitivityphenotypes consistent with those of other CHO cell ERCC1 mutants.Mutation frequency experiments showed that CHO-7-27 was UV-hypermutableat the hypoxanthine-guanine phosphoribosyltransferase locus.Experiments assessing host cell reactivation of viral DNA synthesisfor UV-irradiated adenovirus showed that CHO7-27 exhibited aseverely deficient HCR phenotype similar to that of UV20 cells.Our results demonstrate that CHOK1 cells are hemizygous forthe ERCC1 gene, and show that the comparatively mild mutagensensitivities and lack of severely deficient HCR phenotypesof conventionally derived CHO-K1 ERCC1 mutants, in contrastto the severe phenotypes of CHO-AA8-derived mutants, are notdue to any intrinsic genetic differences between CHO-K1 andCHO-AA8 parental cell lines.
4To whom correspondence should be addressed 相似文献
87.
88.
Effects of Ethanol in an Experimental Model of Combined Traumatic Brain Injury and Hemorrhagic Shock 总被引:3,自引:2,他引:1
Brian J. Zink MD Susan A. Stern MD Xu Wang MD Carl C. Chudnofsky MD 《Academic emergency medicine》1998,5(1):9-17
Objectives: Given that clinical and laboratory studies suggest that ethanol and hemorrhagic shock (HS) potentiate traumatic brain injury (TBI), the authors studied the effects of ethanol in a model of combined TBI and HS.
Methods: A controlled porcine model of combined TBI and HS was evaluated for the effect of ethanol on survival time, hemodynamic function, and cerebral tissue perfusion. Anesthetized swine (17–24 kg) were instrumented, splenectomized, and subjected to fluid percussion TBI with concurrent 25-mL/kg graded hemorrhage over 30 minutes. Two groups were studied: control ( n = 11) and ethanol ( n = 11). Ethanol, 3.5 g/kg intragastric, was given 100 minutes prior to TBI/HS. Systemic and cerebral physiologic and metabolic parameters were monitored for 2 hours without resuscitation. Regional cerebral blood flow (rCBF) and renal blood flow were measured with dye-labeled microspheres. Data were analyzed with 2-sample t-test and repeated-measures ANOVA.
Results: Ethanol levels at the time of injury were 162 ± 68 mg/dL. Average TBI was 2.65 ± 0.35 atm. Survival time was significantly shorter in the ethanol group (60 ± 27 min vs 94 ± 28 min, p = 0.011). The ethanol group had significantly lower mean arterial pressure, cerebral perfusion pressure, and cerebral venous
O2 saturation in the postinjury period. Cerebral O2 extraction ratios and cerebral venous lactate levels were significantly higher in the ethanol group. A trend toward lower postinjury rCBF in all brain regions was observed in the ethanol group.
Conclusion: In this TBI/HS model, ethanol administration decreased survival time, impaired the hemodynamic response, and worsened measures of cerebral tissue perfusion. 相似文献
Methods: A controlled porcine model of combined TBI and HS was evaluated for the effect of ethanol on survival time, hemodynamic function, and cerebral tissue perfusion. Anesthetized swine (17–24 kg) were instrumented, splenectomized, and subjected to fluid percussion TBI with concurrent 25-mL/kg graded hemorrhage over 30 minutes. Two groups were studied: control ( n = 11) and ethanol ( n = 11). Ethanol, 3.5 g/kg intragastric, was given 100 minutes prior to TBI/HS. Systemic and cerebral physiologic and metabolic parameters were monitored for 2 hours without resuscitation. Regional cerebral blood flow (rCBF) and renal blood flow were measured with dye-labeled microspheres. Data were analyzed with 2-sample t-test and repeated-measures ANOVA.
Results: Ethanol levels at the time of injury were 162 ± 68 mg/dL. Average TBI was 2.65 ± 0.35 atm. Survival time was significantly shorter in the ethanol group (60 ± 27 min vs 94 ± 28 min, p = 0.011). The ethanol group had significantly lower mean arterial pressure, cerebral perfusion pressure, and cerebral venous
O
Conclusion: In this TBI/HS model, ethanol administration decreased survival time, impaired the hemodynamic response, and worsened measures of cerebral tissue perfusion. 相似文献
89.
The neurotransmitter biosynthetic enzymes, tyrosine hydroxylase (TH), and tryptophan hydroxylase (TPH) are each composed of
an amino-terminal regulatory domain and a carboxylterminal catalytic domain. A chimeric hydroxylase was generated by coupling
the regulatory domain of TH (TH-R) to the catalytic domain of TPH (TPH-C) and expressing the recombinant enzyme in bacteria.
The chimeric junction was created at proline 165 in TH and proline 106 in TPH because this residue is within a conserved five
amino-acid span (ValProTrpPhePro) that defines the beginning of the highly homologous catalytic domains of TH and TPH. Radioenzymatic
activity assays demonstrated that the TH-R/TPH-C chimera hydroxylates tryptophan, but not tyrosine. Therefore, the regulatory
domain does not confer substrate specificity. Although the TH-R/TPH-C enzyme did serve as a substrate for protein kinase (PKA),
activation was not observed following phosphorylation. Phosphorylation studies in combination with kinetic data provided evidence
that TH-R does not exert a dominant influence on TPH-C. Stability assays revealed that, whereas TH exhibited a t1/2 of 84 min at 37°C, TPH was much less stable (t
1/2=28.3 min). The stability profile of TH-R/TPH-C, however, was superimposable on that of TH. Removal of the regulatory domain
(a deletion of 165 amino acids from the N-terminus) of TH rendered the catalytic domain highly unstable, as demonstrated by
at
1/2 of 14 min. The authors conclude that the regulatory domain of TH functions as a stabilizer of enzyme activity. As a corollary,
the well-characterized instability of TPH may be attributed to the inability of its regulatory domain to stabilize the catalytic
domain. 相似文献
90.
Neonatal autopsy findings are valuable additions to the information base for current cases and future perinatal care, so the reported decline in the autopsy rate is disturbing. In order to estimate the prevalence of the neonatal autopsy among a large population of deaths, we surveyed participating institutions of the Study Group for Complications of Perinatal Care. Investigators from 37 neonatal intensive care units, located in 9 children's hospitals, 4 hospitals for women and infants, and 24 full-service pediatric and adult care hospitals, reported their neonatal death and autopsy rates for 1989. The overall neonatal autopsy rate was 51% among 1645 neonatal deaths. The rate was variable, ranging from 22 to 100%. We found the neonatal autopsy rate to be lower than previously reported and not apparently influenced by the type of center or by the type of medical staff at the centers. In order to assess and potentially reverse the current low rate, the influence of neonatal demographic and clinical factors, as well as physician-related factors, must be studied. 相似文献