On the use of historical control data to estimate dose response trends in quantal bioassay.

New tests for trend in proportions, in the presence of historical control data, are proposed. One such test is a simple score statistic based on a binomial likelihood for the "current" study and beta-binomial likelihoods for each historical control series. A closely related trend statistic based on estimating equations is also proposed. Trend statistics that allow overdispersed proportions in the current study are also developed, including a version of Tarone's (1982, Biometrics 38, 215-220) test that acknowledges sampling variation in the beta distribution parameters, and a trend statistic based on estimating equations. Each such trend test is evaluated with respect to size and power under both binomial and beta-binomial sampling conditions for the current study, and illustrations are provided.     

Inhibition of Nb2 T-lymphoma cell growth by transforming growth factor-beta.

1. Mitochondria isolated from the gut-dwelling nematodes Nippostrongylus brasiliensis and Ascaridia galli (muscle and gut + reproductive tissue) were examined for cytochromes, and it was observed that N. brasiliensis and A. galli muscle tissue mitochondria contained a-, b- and c-type cytochromes, but their stoichiometries were quite different (1:2:1.9 and 1:11.4:13.6 respectively); A. galli gut + reproductive-tissue mitochondria, however, only contained b and c cytochromes, in a ratio of 1:0.8. 2. CO difference spectra showed the presence of CO-reacting b-type cytochrome(s) in all three types of mitochondria; the fast-reacting species comprised 30, 44 and 39% of the total in N. brasiliensis, A. galli muscle and A. galli gut + reproductive-tissue mitochondria respectively. 3. Cytochrome aa3 was observed in N. brasiliensis mitochondria and in those from A. galli muscle, but was below the level of detectability (less than 0.005 nmol/mg of protein) for A. galli gut + reproductive-tissue mitochondria. 4. Photochemical action spectra for the reversal of CO inhibition of the endogenous respiration of whole worms (at 24 microM- and 40 microM-O2 respectively for N. brasiliensis and A. galli) gave maxima at 598 and 542-543 nm, corresponding to the alpha- and beta-absorption maxima of cytochrome aa3, and at 567 nm (b-type cytochrome) for both worms. These results suggest that cytochrome aa3 is the major functional oxidase in N. brasiliensis, whereas the CO-reacting b-type cytochrome dominates in A. galli.     

A medium for the detection of Lancefield Group D cocci in skimmed milk powder by measurement of conductivity changes

A selective medium for the detection of Lancefield Group D cocci in skimmed milk powder by conductivity measurements was developed and evaluated using the Bactometer M123 and Malthus 128H systems. This medium promoted large changes in conductance and capacitance. The calibration curve of detection times vs concentration of Lancefield Group D cocci showed a linear correlation coefficient of 0.93 and the method gave comparable results in both conductivity instruments. Naturally contaminated samples containing c. 10(3) cfu/g of Lancefield Group D cocci gave detection times within 16-18 h which was sufficiently rapid for the medium to be used for the routine screening of skimmed milk powder.     

Possible Pathogenesis of Motility Changes in Diffuse Esophageal Spasm Associated with Gastric Carcinoma

A theory is proposed according to which diffuse esophageal spasm associated with carcinoma may be secondary to neural damage due to invasion by carcinoma without obstruction of the esophageal lumen. A case history is presented to support this theory.     

Beneficial effect of taurine on hypoxia- and glutamate-induced endoplasmic reticulum stress pathways in primary neuronal culture

Stroke (hypoxia) is one of the leading causes of mortality in the developed countries, and it can induce excessive glutamate release and endoplasmic reticulum (ER) stress. Taurine, as a free amino acid, present in high concentrations in a range of organs in mammals, can provide protection against multiple neurological diseases. Here, we present a study to investigate the potential protective benefits of taurine against ER stress induced by glutamate and hypoxia/reoxygenation in primary cortical neuronal cultures. We found that taurine suppresses the up-regulation of caspase-12 and GADD153/CHOP induced by hypoxia/reoxygenation, suggesting that taurine may exert a protective function against hypoxia/reoxygenation by reducing the ER stress. Moreover, taurine can down-regulate the ratio of cleaved ATF6 and full length ATF6, and p-IRE1 expression, indicating that taurine inhibits the ER stress induced by hypoxia/reoxygenation and glutamate through suppressing ATF6 and IRE1 pathways.