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41.
The present study investigated the temporal structure of sleep propensity during 48 hours using an ultrashort 7-min sleep/13-min wake cycle. Eight subjects were tested under two experimental conditions of either attempting sleep, or resisting sleep after a monitored night in the laboratory. Electrophysiological recordings were carried out during the 7-min trials. The temporal structure and the overall level of sleepiness of the 48-hour sleep propensity functions calculated from the amount of total sleep in each trial revealed a high within-subjects stability. This was found both across the two days of the study within conditions, and across conditions. Also, diurnal levels of sleepiness were systematically related to nocturnal sleep parameters. Subjects having short nocturnal sleep latencies and higher sleep efficiencies slept more during the day. It is proposed that the structure and level of the sleep propensity function can be used to characterize individuals along two dimensions of somnotypology: "morningness-eveningness" and "sleepy-alert." 相似文献
42.
Muhammad Jamshaid Samia Yousuf Nadeem Irfan Bukhari Amir Ali Rizvi 《European journal of drug metabolism and pharmacokinetics》2003,28(1):1-6
Three commercially available brands of amikacin were investigated in a parallel study design for the assessment of comparative pharmacokinetics in pediatric oncology patients with chemotherapy-induced neutropenic febrile episode. Amikacin concentration in serum samples was determined by fluorescence polarization immunoassay method using Abbott TDx system. Computer software, PK II was used for computation of pharmacokinetic parameters of amikacin. The serum concentration of all brands nonsignificantly (p > 0.05) varied at all time points, except at 1 and 2 hrs post dosing. At 1 hr post dosing, the serum concentration of brand II varied from rest of two brands. Whereas at 2 hr following I/V infusion, brands II and I were statistically different. Highest serum concentration of 38.69 +/- 1.45 microg/ml was observed in case of brand III while brands I and II showed lower but not significantly different serum concentration values, i.e., 36.30 +/- 1.65 and 37.89 +/- 1.32 microg/ml, respectively when compared with brand I. The other pharmacokinetic parameters of 3 brands found to have non-significant difference (P < 0.05) except, t(1/2)alpha and Cl of brands I and II that deviated statistically significant (p < 0.01). The relative bioavailability of brand II and III as compared with brand I, considered as standard 86.17 and 96.86%, respectively falls within the accepted limits of +/- 20% required for the bioequivalence of any two brands. Based upon findings of the present study, all these brands may be used interchangeably in oncology patients. Further studies, however are needed to determine whether the statistically elevated Cl value in brand II is of any clinical significance. 相似文献
43.
Dina Chelouche Lev Amir Onn Vladislava O Melinkova Claudia Miller Valerie Stone Maribelis Ruiz Eric C McGary Honnavara N Ananthaswamy Janet E Price Menashe Bar-Eli 《Journal of clinical oncology》2004,22(11):2092-2100
PURPOSE: In recent years, the incidence of cutaneous melanoma has increased more than that of any other cancer. Dacarbazine is considered the gold standard for treatment, having a response rate of 15% to 20%, but most responses are not sustained. Previously, we have shown that short exposure of primary cutaneous melanoma cells to dacarbazine resulted in the upregulation of interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF). The purpose of the present study was to determine how long-term exposure of melanoma cells to dacarbazine would affect their tumorigenic and metastatic potential in vivo. MATERIALS AND METHODS: The primary cutaneous melanoma cell lines SB2 and MeWo were repeatedly exposed in vitro to increasing concentrations of dacarbazine, and dacarbazine-resistant cell lines SB2-D and MeWo-D were selected and examined for their ability to grow and metastasize in nude mice. RESULTS: The dacarbazine-resistant cell lines SB2-D and MeWo-D exhibited increased tumor growth and metastatic behavior in vivo. This increase could be explained by the activation of RAF, MEK, and ERK, which led to the upregulation of IL-8 and VEGF. More IL-8, VEGF, matrix metalloproteinase-2 (MMP-2), and microvessel density (CD-31) were found in tumors produced by SB2-D and MeWo-D in vivo than in those produced by their parental counterparts. No mutations were observed in BRAF. CONCLUSION: Our results have significant clinical implications. Treatment of melanoma patients with dacarbazine could select for a more aggressive melanoma phenotype. We propose that combination treatment with anti-VEGF/IL-8 or MEK inhibitors may potentiate the therapeutic effects of dacarbazine. 相似文献
44.
Amir Onn Takeshi Isobe Wenjuan Wu Satoshi Itasaka Tomoaki Shintani Keiko Shibuya Yokoi Kenji Michael S O'reilly Isaiah J Fidler Roy S Herbst 《Clinical cancer research》2004,10(24):8613-8619
PURPOSE: The purpose is to evaluate whether inhibition of epidermal growth factor receptor (EGFR) activation by PKI166, an EGFR-tyrosine kinase inhibitor, affects growth of human lung cancer implanted orthotopically into the lungs of nude mice. EXPERIMENTAL DESIGN: Lungs of mice were injected with NCI-H358 human bronchioloalveolar cancer cells. In three experiments, groups of mice (n = 10 per group) were randomized 7 days after tumor implantation to receive one of the following treatments: i.p. paclitaxel 100 or 200 microg (4 or 8 mg/kg) once per week, oral PKI166 100 or 200 mg/kg three times per week, paclitaxel plus PKI166, or i.p. saline and oral PKI166-vehicle (control) for 5 weeks. Mice were killed 6.5 to 8 weeks after tumor implantation. The experiments were repeated with PC14PE6 human lung adenocarcinoma cells to assess effect on survival. RESULTS: Immunohistochemical analyses revealed the expression and phosphorylation of EGFR in the growing tumors. Treatment with PKI166 alone or in combination with paclitaxel diminished activation of EGFR on tumor cells, yet maximal therapeutic effect was observed in mice treated with paclitaxel alone. Activated mitogen-activated protein kinase and basic fibroblast growth factor expression were similar in all treatment groups. Survival in mice treated with the combination of paclitaxel and PKI166 was shorter than in those treated with paclitaxel alone. CONCLUSIONS: Our results suggest that concurrent administration of EGFR-tyrosine kinase inhibitor and chemotherapy is equivalent and may indeed be inferior to chemotherapy alone, even if EGFR is functional and its phosphorylation effectively inhibited. Our data show that the interaction of EGFR-TKIs and chemotherapy is complex and suggest that other growth factors may activate the downstream signaling events. 相似文献
45.
Amir Shmueli Mario Baras Charles L. Sprung 《Health services & outcomes research methodology》2004,5(3-4):163-174
Intensive Care Units (ICU) are one of the most powerful and expensive technologies within inpatient care. However, its effect
on survival is still an issue under discussion. The objective of this paper is to assess the effect of General ICU on in-hospital
survival. We assessed the effect of ICU on survival using Linear and Probit regressions. Since admission to IC is not random
and depends on unobserved (to the researcher) heterogeneity, we reassessed the IC effect by Instrumental Variables (IV) and
Bivariate Probit techniques, using crowding in the IC unit as an instrument. The results show that a simple Probit of the
IC effect on survival is 7–10 percentage-points (pts). The IV estimate of the IC effect on survival is 21–34 pts, and the
Bivariate Probit estimate is 17–21 pts.
We conclude that although admitted patients are at lower risk of death, as determined by their observable (to the researcher)
characteristics, controlling for observable differences, those with a higher unobserved risk of mortality are more likely
to be admitted. The implications for an optimal admission policy are discussed. 相似文献
46.
47.
Potentiation of tumor response to radiation or chemoradiation by selective cyclooxygenase-2 enzyme inhibitors 总被引:15,自引:0,他引:15
Nakata E Mason KA Hunter N Husain A Raju U Liao Z Ang KK Milas L 《International journal of radiation oncology, biology, physics》2004,58(2):369-375
Cyclooxygenase-2 (COX-2) is an enzyme expressed primarily in pathologic states, such as inflammatory disorders and cancer, where it mediates prostaglandin production. Its overexpression is associated with more aggressive biologic tumor behavior and adverse patient outcome. Increasing evidence shows that agents that selectively inhibit COX-2 enhance tumor response to radiation or chemotherapeutic agents. This article gives an overview of some of this evidence. In addition, we describe new results showing that celecoxib, a selective COX-2 inhibitor, enhanced response of A431 human tumor xenografts in nude mice to radiation by an enhancement factor (EF) of 1.43 and to the chemotherapeutic agent docetaxel by an EF of 2.07. Celecoxib also enhanced tumor response when added to the combined docetaxel plus radiation treatment (EF = 2.13). Further experiments showed that selective COX-2 inhibitors enhanced tumor cell sensitivity to ionizing radiation, involving inhibition of cellular repair from radiation damage and cell cycle redistribution as mechanisms for some cell types. The results show that selective COX-2 inhibitors have the potential to improve tumor radiotherapy or radiochemotherapy, and this therapeutic strategy is currently under clinical testing. 相似文献
48.
49.
El-Shawarby SA Ravhon A Skull J Ellenbogen A Trew G Lavery S 《Reproductive biomedicine online》2008,17(4):549-552
The aim of this study was to compare the efficacy of two embryo transfer catheters: Wallace and Rocket Embryon in an IVF programme of a tertiary referral university centre. A total of 308 patients undergoing embryo transfer were prospectively randomized to either a transfer with the Wallace catheter or a transfer with the Rocket catheter. The main outcome measure in this study was the clinical pregnancy rate, and secondary outcome measures included implantation rate, visibility of the catheter under ultrasound, number of retained embryos post transfer, and whether change of catheter was required. In addition, patient discomfort during the procedure was recorded. Pregnancy and implantation rates were similar when Wallace or Rocket catheters were used. However, for the Rocket catheter, the tip was more often clearly seen on ultrasound and it had a lower rate of retained embryos in the catheter after transfer (P < 0.05). Experience with different transfer catheters is recommended for difficult cases. 相似文献
50.