Means survival data

Tumors were not observed in male rats treated with 19 mg/kg/day doses of 1,2-diphenylhydrazine in the diet for life (mean survival time = 288 days) (Marhold et al. 1968). The significance of this finding is uncertain because the type and scope of pathological examination were not reported. Pliss (1974) reported increased numbers of tumors of the liver, Zymbal s gland, mammary gland and other sites in rats that were treated with 1,2-diphenylhydrazine in the diet at an estimated dose of 85 mg/kg/day, 5 days/week for 588 days (Pliss 1974). These findings are inconclusive, however, because of lack of control data and other report inadequacies. 

Each trial that is to be included in the meta-analysis will provide a measure of treatment effect (difference). For continuous data this could be the mean response on the active treatment minus the mean response in the placebo arm. Alternatively, for binary data the treatment effect could be captured by the difference in the cure rates, for example, or by the odds ratio. For survival data, the hazard ratio would often be the measure of treatment difference, but equally well it could be the difference in the two-year survival rates. 

In a fashion similar to the discussion presented on organic chemicals, Baas et al. (2007) applied the 1-compartment model without TK interactions for the analysis of-time series survival data for the springtail Folsomia Candida exposed to binary mixtures of heavy metals. It must be stressed that no internal concentrations were measured in these experiments instead, the toxicokinetics parameters were solely determined from the survival pattern in time. In this case, the toxicity data were well described without assuming interactions, which stresses that even though we know that interactions on toxicokinetics can occur, this does not mean that they will significantly influence toxicity for every metal mixture in each organism. 

Although inhalational botulinum intoxication was investigated in other animal species, these studies have not provided specific data on toxin absorption. The behavior of BoNTs in the respiratory tract was only recently investigated. Park and Simpson (2003) studied the properties of pure BoNT/A neurotoxin both in vivo and in vitro using mice and pulmonary cell culture models, respectively. Mean survival times were compared in mice receiving various doses of pure BoNT/A either IN or IP. Pure BoNT/A was found to be a potent intranasal poison, although the toxicity (as determined by mean survival time) associated with IP administration was somewhat higher. Mean survival times in mice were less than 100 (IP) or 600 min (IN) after administration of 0.1 pg pure toxin 75 (IP) or 400 min (IN) for 1 pg toxin and 120 min (IN) for 10 pg toxin (Park and... 

When analyzing survival data, summary statistics may not have the desired statistical properties, such as unbiasedness, because of possible censoring. The sample mean, for instance, is no longer an unbiased estimator of the population mean (of survival time). Thus, other methods are needed for presenting such data. An approach would be estimating the underlying true distribution. With the distribution estimated, it is then possible to estimate other quantities of interest such as median or mean. The distribution of the random variable T can be described by the usual cumulative distribution function... 

New York Heart Association (NYHA) class III or IV or six-minute walk tests less than 332 meters do poorly (6). Of note, the prognosis of patients treated in the modern era with intravenous epoprostenol is improved. Although survival data is limited, comparisons are made to outdated historical controls of the 1991 NIH study, and most randomized clinical data are limited to industry-sponsored studies of 12- to 16-week duration with extension phases. This disease has a female predominance, with a mean age of diagnosis of 36.4 years. 

In all experiments MHC class II expression was measured by cytofluorometry the values were corrected for isotype controls only viable cells were considered in experiments where >90% of PMN had survived. Data represent mean SD of independent experiments using cells of different donors. 

Fig. IB. The effect of SAB on the repair kinetics of potentially lethal damage in normal human fibroblasts, Ewing s sarcoma, and human lung adenocarcinoma. No inhibitor (open circles) 8SAB (closed circles). Data points are means 1 standard deviation. Both normal fibroblast and human tumor cell cultures were grown and maintained in Eagle s MEM supplemented with 10% (VA ) fetal bovine serum, streptomycin and penicillin, at S7°C in a humidified chamber of 95% air and 5% CO2. Stock cultures in exponential growth were detached by trypsinization and appropriate cell numbers plated in 25 cm flasks and incubated to permit cell attachment. Inhibitors of poly(ADP-ribose) synthetase (SAB or BZ) were added to the appropriate cultures 2 hr prior to irradiation in air at room temperature. Following irradiation, the cells were exposed to the inhibitors for 24 hr, washed, and replenished with fresh medium. Refeeding was performed every S days and after 10-14 days, cells were fixed and the colonies stained with Giemsa. Only colonies of 50 cells or more were scored as survivors. All experiments were performed in triplicate and the survival data expressed as the mean S.E. of three separate survival experiments.

Fig. 3.1.2. Survival data calculated by the Kaplan-Meier method for patients with hepatocellular carcinoma (HCC) treated only with (-) TACE n = 123) or patients n = 32) treated with (—) the combined treatment protocol (TACE followed by LITT). The mean survival of patients with TACE treatment was 25.0 months and significant lower than the median survival of 36.0 months in patients treated with the combined protocol...

Fig. 5. HuTu80 human colon cancer cells are radiosensitized by FddUrd. HuTu80 cells were irradiated under control conditions (O) or after a 14-h exposure to 100 nmol L FdUrd ( ). They were then assessed doe survival using a clonogenic assay. Data are expresses as the mean (point) SE (bar), which is within the symbol unless indicated.

Figures presented in various sections apply to experiments in which pure cultures have been irradiated in a controlled medium. In actual practice one is faced with the problem of producing an arbitrarily defined level of commercial sterility in an undefined medium with a mixed population. Commercial sterility can mean anywhere from 10 8 to 10 ia organism/g. depending on the product and type of contamination. Systematic data which would give the detailed shape of the survival curve in the region of commercial interests are nonexistent. The results of a number of experiments in which workers claimed to have achieved sterility are tabulated in Table VII. In nearly all cases insufficient data were obtained to allow a satisfactory statistical evaluation. Furthermore, differences and confusion in the dosimetry make the data rather approximate.

Dry matter yield averaged over two harvests each year. b Yield data in parentheses were not included in statistical analysis because an insufficient number of plants survived the preceding winter. c Standard error of the mean. 

In Figure 10.30 the survival rate of the total sedimentary mass for the different Phanerozoic systems is plotted and compared with survival rates for the total carbonate and dolomite mass distribution. The difference between the two latter survival rates for each system is the mass of limestone surviving per unit of time. Equation 10.1 is the log linear relationship for the total sedimentary mass, and implies a 130 million year half-life for the post-Devonian mass, and for a constant sediment mass with a constant probability of destruction, a mean sedimentation rate since post-Devonian time of about 100 x 1014 g y 1. The modem global erosional flux is 200 x 1014 g y-1, of which about 15% is particulate and dissolved carbonate. Although the data are less reliable for the survival rate of Phanerozoic carbonate sediments than for the total sedimentary mass, a best log linear fit to the post-Permian preserved mass of carbonate rocks is... 

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