Oxidative phosphorylation and ATPase activities of human tumor mitochondria

Studies were carried out with intact mitochondria isolated from human astrocytoma, oat cell carcinoma and melanoma which were propagated in athymic mice. These human tumor mitochondria were capable of coupled oxidative phosphorylation. They also showed significant uncoupler-stimulated ATPase if defatted bovine serum albumin was included in the assay media. However, the uncoupler response curves were different and the magnitude of the ATPase activity was lower than could be obtained with mitochondria of a normal tissue, such as liver. Some of these characteristics were also exhibited by mitochondria from several animal hepatomas and Ehrlich ascites tumor. In the three tumors studied, mitochondria from oat cell carcinoma were more labile, whereas higher respiratory control ratios and greater stimulation of ATPase by uncouplers were obtained with melanoma mitochondria.The mitochondrial ATPase was not the major cellular ATPase in any of the three tumors. This was indicated by a low inhibition of the ATPase activity of tumor cell homogenates by oligomycin. A very large fraction of the cellular ATPase activities was recovered in the microsomal fractions.     

A genetic study of bovine lymphocyte antigens (BoLA) and their frequency in several breeds

Using sera which defined the BoLA specificities at the two International BoLA workshops (Edinburgh, 1978 and Wageningen, 1980) and the European Regional workshop (Paris, 1979),142 informative matings from 15 bulls have been studied. On the basis of this data, 11 of the 15 internationally agreed specificities and one of the regionally defined specificities behave as if controlled by alleles at a single autosomal locus. Data has not as yet been obtained for the other four internationally agreed specificities which are also believed to be at this locus. — The frequencies of 13 of the internationally agreed specificities and one of the regionally defined specificities have been studied for both sexes in one breed and for a single sex in another five breeds. The other two internationally agreed specificities are very recent and the populations have not been tested for them. The frequencies between sexes within a breed and within sexes between breeds differ significantly.     

Evaluation of Rosette Inhibition Test in Renal Transplantation

Serial rosette inhibition tests were performed on 11 renal transplant patients in an attempt to predict graft rejection. The rosette inhibition titre was higher in immunosuppressed patients than in normal subjects. The test was of predictive value in only two out of 12 rejection episodes, where a fall in titre to normal levels occurred 48 hours and 24 hours, respectively, before biochemical evidence of rejection. In two further rejection episodes the titre fell at the time of rejection. The titre changes in all tests were small and there were frequent inconsistencies in the results of individual tests. A study of the variables was undertaken, with standardization of the technique, and improvements were made in reading the test. Despite these changes the test was still not sufficiently accurate or reliable to be used as the basis of treatment of rejection episodes.     

Recruitment and metamorphosis of Haliotis larvae induced by molecules uniquely available at the surfaces of crustose red algae

Crustose red algae induce substratum-specific settlement, attachment and metamorphosis of the planktonic larvae of Haliotis rufescens Swainson (gastropod mollusc), upon direct contact by the larvae with any of a number of algal species tested. Larvae are not induced by contact with intact foliose red, brown or green macroalgae. Geniculate red algae are only slightly active. Larval settlement and metamorphosis are shown to be triggered by a class of chemical inducers associated with macromolecules and found in extracts of all species of crustose, geniculate, and foliose red algae tested; these inducers are not found in extracts of brown or green macroalgae. The substratum specificity of larval settlement and metamorphosis is shown to result from the unique availability of these inducers at the surfaces of the crustose red algae. Using a newly-developed improved method of purification based upon size-separation by gel-filtration, followed by ion-exchange chromatography over a diethylaminoethyl (DEAE)-acrylamide matrix, the principal inducer of Haliotis larval settlement and metamorphosis has been resolved from the red algal phycobiliproteins. Sensitivity of this inducer to reduction in molecular weight by digestion with trypsin demonstrates that this inducer is associated with protein.     

The Forgotten Role of Central Volume in Low Frequency Oscillations of Heart Rate Variability

The hypothesis that central volume plays a key role in the source of low frequency (LF) oscillations of heart rate variability (HRV) was tested in a population of end stage renal disease patients undergoing conventional hemodialysis (HD) treatment, and thus subject to large fluid shifts and sympathetic activation. Fluid overload (FO) in 58 chronic HD patients was assessed by whole body bioimpedance measurements before the midweek HD session. Heart Rate Variability (HRV) was measured using 24-hour Holter electrocardiogram recordings starting before the same HD treatment. Time domain and frequency domain analyses were performed on HRV signals. Patients were retrospectively classified in three groups according to tertiles of FO normalized to the extracellular water (FO/ECW%). These groups were also compared after stratification by diabetes mellitus. Patients with the low to medium hydration status before the treatment (i.e. 1st and 2nd FO/ECW% tertiles) showed a significant increase in LF power during last 30 min of HD compared to dialysis begin, while no significant change in LF power was seen in the third group (i.e. those with high pre-treatment hydration values). In conclusion, several mechanisms can generate LF oscillations in the cardiovascular system, including baroreflex feedback loops and central oscillators. However, the current results emphasize the role played by the central volume in determining the power of LF oscillations.     

The application of MANOVA to analyse <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis> metabolomic data from factorially designed experiments

Metabolomic technologies produce complex multivariate datasets and researchers are faced with the daunting task of extracting information from these data. Principal component analysis (PCA) has been widely applied in the field of metabolomics to reduce data dimensionality and for visualising trends within the complex data. Although PCA is very useful, it cannot handle multi-factorial experimental designs and, often, clear trends of biological interest are not observed when plotting various PC combinations. Even if patterns are observed, PCA provides no measure of their significance. Multivariate analysis of variance (MANOVA) applied to these PCs enables the statistical evaluation of main treatments and, more importantly, their interactions within the experimental design. The power and scope of MANOVA is demonstrated through two different factorially designed metabolomic investigations using Arabidopsis ethylene signalling mutants and their wild-type. One investigation has multiple experimental factors including challenge with the economically important pathogen Botrytis cinerea and also replicate experiments, while the second has different sample preparation methods and one level of replication ‘nested’ within the design. In both investigations there are specific factors of biological interest and there are also factors incorporated within the experimental design, which affect the data. The versatility of MANOVA is displayed by using data from two different metabolomic techniques; profiling using direct injection mass spectroscopy (DIMS) and fingerprinting using fourier transform infra-red (FT-IR) spectroscopy. MANOVA found significant main effects and interactions in both experiments, allowing a more complete and comprehensive interpretation of the variation within each investigation, than with PCA alone. Canonical variate analysis (CVA) was applied to investigate these effects and their biological significance. In conclusion, the application of MANOVA followed by CVA provided extra information than PCA alone and proved to be a valuable statistical addition in the overwhelming task of analysing metabolomic data.     

Cutting edge: Decreased accumulation and regulatory function of CD4+ CD25(high) T cells in human STAT5b deficiency

We show that STAT5b is important for the in vivo accumulation of CD4+ CD25(high) T cells with regulatory cell function. A patient homozygous for a missense A630P STAT5b mutation displayed immune dysregulation and decreased numbers of CD4+ CD25(high) T cells. STAT5b(A630P/A630P) CD4+ CD25(high) T cells had low expression of forkhead box P3 and an impaired ability to suppress the proliferation of or to kill CD4+ CD25- T cells. Expression of CD25, a component of the high-affinity IL-2R, was also reduced in response to IL-2 or after in vitro propagation. The impact of the STAT5b mutation was selective in that IL-2-mediated up-regulation of the common gamma-chain cytokine receptor and perforin, and activation-induced expressions of CD154 and IFN-gamma were normal. These results indicate that STAT5b propagates an important IL-2-mediated signal for the in vivo accumulation of functional regulatory T cells.