The Vancouver Lymphadenopathy-AIDS Study: 4. Effects of exposure factors,cofactors and HTLV-III seropositivity on number of helper T cells.

Results of testing for antibody to human T-lymphotropic virus (HTLV-III) and absolute numbers of helper T cells in 219 participants in the Vancouver Lymphadenopathy-AIDS (acquired immune deficiency syndrome) Study were analysed. The mean absolute helper T-cell counts in the 141 HTLV-III seronegative and the 78 seropositive men were 897/mL and 659/mL respectively (p less than 0.001). Established AIDS risk factors such as elevated lifetime number of male sexual partners and frequent receptive anal intercourse did not appear to have any significant effect on number of helper T cells that was independent of HTLV-III antibody status. Seropositive men with less than 100, 100 to 500 or more than 500 male sexual partners in their lifetime had mean absolute helper T-cell counts of 667/mL, 651/mL and 662/mL respectively. Most other risk factors, as well, did not appear to exert any effect on absolute number of helper T cells that was independent of the effect of HTLV-III antibody status. However, independent effects of a history of mononucleosis or hepatitis and of cigarette smoking were noted. The data support the hypothesis that no immune dysfunction beyond that due to the initial infection alone arises from repeated exposure to HTLV-III. Most risk factors appear to act as exposure factors, exerting their effect on the immune system merely by increasing the probability of contact with the agent. The independent effects of a history of mononucleosis or hepatitis suggest that viral agents may be cofactors in the production of immune dysfunction.     

Characterization of nonactivated and activated glucocorticoid-receptor complexes from intact rat thymus cells

In cells exposed to glucocorticoids at 37 degrees C activated glucocorticoid-receptor complexes (complexes with affinity for nuclei and DNA) are formed after nonactivated complexes. Activation thus appears to be an obligatory physiological process. To investigate this process we have characterized cytoplasmic complexes formed in rat thymocytes at 0 and 37 degrees C. Complexes in cytosols stabilized with molybdate were analyzed by sucrose gradient centrifugation and by chromatography on DNA-cellulose, DEAE-cellulose, and agarose gels. Two major complexes were observed: the nonactivated complex, eluted from DEAE at approximately 200 mM KCl, was formed at 0 and 37 degrees C, gave S20,w = 9.2 S, Stokes radius = 8.3 nm, and calculated Mr = 330,000; the activated complex, eluted from DEAE at approximately 50 mM KCl, appeared only at 37 degrees C, gave S20,w = 4.8 S, Stokes radius = 5.0 nm, and Mr = 100,000. A third, minor complex, probably mero-receptor, which appeared mainly at 37 degrees C, bound to neither DNA nor DEAE, and gave S20,w = 2.9 S, Stokes radius = 2.3 nm, and Mr = 27,000. With three small columns in series (DNA-cellulose, DEAE-cellulose and hydroxylapatite), the three complexes can be separated in 5-10 min. By this method we have examined the stability of complexes under our conditions. We conclude that in intact thymus cells glucocorticoid-receptor complexes occur principally in two forms, nonactivated and activated, and that activation is accompanied by a large reduction in size. The origin of the mero-receptor complex remains uncertain.     

Vitamin K and oxidative phosphorylation

1. Oxidative phosphorylation was studied in a cell-free preparation of Mycobacterium phlei and in rat-liver mitochondria. Phosphorylation was destroyed in both systems by long-wave ultraviolet radiation and restored by the addition of small amounts of [2-Me-(14)C,(3)H]phylloquinone. When the radioactive quinones were recovered from the phosphorylating system and chromatographed with carrier phylloquinone and menaquinone-4 in adsorption and partition systems, only the phylloquinone band was labelled, and its isotopic ratio was identical with that of the original [2-Me-(14)C,(3)H]phylloquinone. This result does not support the contention that the role of vitamin K in oxidative phosphorylation involves a cyclic mechanism with intermediate formation of a quinone methide. 2. When the [2-Me-(14)C,(3)H]phylloquinone was given intravenously to rats and radioactive phylloquinone isolated from their liver mitochondria and microsomes 20hr. later, its isotopic ratio was unchanged. There was thus no evidence for quinone methide formation in vivo. No measurable conversion of phylloquinone into menaquinone-4 was observed. 3. When [(14)C]menadione was given intraperitoneally to rats whose alimentary tract had been treated with neomycin, conversion into menaquinone-4 was found in the liver mitochondria and microsomes, but there was also some indication that there had been synthesis of phylloquinone.     

Xylitol formation by Candida boidinii in oxygen limited chemostat culture

Summary Production of xylitol by Candida boidinii NRRL Y-17213 occurs under conditions of an oxygen limitation. The extent to which substrate is converted to xylitol and its coproducts (ethanol, other polyols, acetic acid), and the relative flow rates of substrate to energetic and biosynthetic pathways is controlled by the degree of oxygen limitation.With decrease in oxygen concentration in the inlet gas, for a constant dilution rate of 0.05 1/h. the specific oxygen uptake rate decreased from 1.30 to 0.36 mmol/gh Xylitol was not produced at specific oxygen uptake rates above 0.91 mmol/gh. Upon shift to lower oxygen rates, specific xylitol production rate increased more rapidly than specific ethanol production rate:Nomenclature D dilution rate (1/h) - DOT dissolved oxygen tension (%) - m_o2 maintenance coefficient (mmol O₂/g cell mass h) - q_o2 specific oxygen uptake rate (mmol O₂/g cell mass h) - q_s specific xylose uptake rate (g xylose/g cell mass h) or (mmol xylose/g cell mass h) - q_x specific xylitol production rate (g xylitol/ g cell mass h) or (mmol xylitol/ g cell mass h) - q_e specific ethanol production rate (g ethanol/ g cell mass h) or (mmol ethanol/ g cell mass h) - q_CO2 specific carbon dioxide production rate (mmol CO₂/g cell mass h) - S xylose concentration (g/1) - Y_cm/s cell mass yield coefficient, (g cell mass/mmol xylose) or (g cell mass/ g xylose consumed) - Y_cm/O2 cell mass yield coefficient, (g cell mass/mmol O₂) - Y_X/S xylitol yield coefficient (g xylitol/g xylose consumed) - Y_x/O2 xylitol yield coefficient (g xylitol/mmol O₂) - Y_e/s ethanol yield coefficient (g ethanol/g xylose consumed) - OUR oxygen uptake rate (mmol O₂/1h) - specific growth rate (1/h)     

Production of antibacterial compounds by phylloplane-inhabiting yeasts and yeastlike fungi.

The production of antibacterial compounds by yeasts and yeastlike fungi isolated from the phylloplane is reported. Aureobasidium pullulans, Citeromyces matritensis, Cryptococcus laurentii, Rhodotorula glutinis, and Sporobolomyces roseus produced antibacterial compounds inhibitory to both Pseudomonas fluorescens and Staphylococcus aureus in an overlay bioassay. In contrast, isolates of Candida albicans, Filobasidium uniguttulatum, Saccharomyces cerevisiae, Torulaspora delbruckii, Tremella foliacea, Trichosporon beigelii, and Trichosporon dulcitum obtained from soil or from culture collections did not produce inhibitory compounds when screened by the same procedure. The production of antibacterial compounds was examined in more detail, using several isolates of A. pullulans distinguished by cluster analysis on the basis of biochemical and physiological tests. They were found to produce a range of antibacterial compounds with different activities. Two distinct antibiotics were produced by an isolate of A. pullulans in liquid culture during both the logarithmic and the stationary phases of growth.     

Comparison of corn steep liquor with other nutrients in the fermentation of D-Xylose by Pichia stipitis CBS 6054

Summary Pichia stipitis CBS 6054 ferments D-Xylose to ethanol in a medium containing corn steep liquor as the only source of nitrogen, amino acids, vitamins and other nutrients. The ethanol yield and fermentation rate compare favorably to those obtained with media containing more expensive sources of nitrogen, vitamins and amino acids. Corn steep liquor is a good source of nutrients that can support growth and fermentation activity of this xylose fermenting yeast.     

Evaluating treatment effects in group sequential multivariate longitudinal studies with covariate adjustment

Jeffries et al. (2018) investigated testing for a treatment difference in the setting of a randomized clinical trial with a single outcome measured longitudinally over a series of common follow-up times while adjusting for covariates. That paper examined the null hypothesis of no difference at any follow-up time versus the alternative of a difference for at least one follow-up time. We extend those results here by considering multivariate outcome measurements, where each individual outcome is examined at common follow-up times. We consider the case where there is interest in first testing for a treatment difference in a global function of the outcomes (e.g., weighted average or sum) with subsequent interest in examining the individual outcomes, should the global function show a treatment difference. Testing is conducted for each follow-up time and may be performed in the setting of a group sequential trial. Testing procedures are developed to determine follow-up times for which a global treatment difference exists and which individual combinations of outcome and follow-up time show evidence of a difference while controlling for multiplicity in outcomes, follow-up, and interim analyses. These approaches are examined in a study evaluating the effects of tissue plasminogen activator on longitudinally obtained stroke severity measurements.     

Analytical isoelectric focusing of secreted dermatophyte proteins applied to taxonomic differentiation of Microsporum and Trichophyton species (preliminary studies)

Culture filtrates were prepared from dermatophytes under standard conditions and adapted for analytical isoelectric focusing in thin layer polyacrylamide gels over the pH range 3.5-9.5. Dermatophytes grown in trypticase soy broth secreted a large number of proteins displaying a wide range of isoelectric points (pIs). Trichophyton megninii extracts contained a triplet of proteins focusing in the pH 8.0-8.5 range that were absent in taxonomically related T. kuryangei isolates. Single ascospore isolates and standard tester strains of Nannizzia otae (+) mating type were differentiated from the (-) mating type by proteins focusing at pH 6.5 and 8.4. These were markedly reduced in the (+) type. The isofocused pattern of Microsporum canis conformed closely to the (-) mating type of N. otae. The protein patterns of T. megninii and T. kuryangei were distinct from those obtained with M. canis and M. equinum because of an intense-staining broad protein band, pI 7.2, and three periodic acid-Schiff-positive glycoproteins focusing in the acidic range which were absent in the Microsporum species. A characteristic protein or doublet (pI 8.7) was present in the Microsporum species and absent in the Trichophyton species. Analytical isoelectric focusing is a potentially useful method to distinguish inter- and intra-species differences in the pattern of secreted dermatophyte proteins present in culture filtrates and in trichophytins. The information derived may be useful in the classification of species.     

Magnesium-induced inner membrane aggregation in heart mitochondria: prevention and reversal by carboxyatractyloside and bongkrekic acid

Mg(2+) at an optimal concentration of 2mM (ph 6.5) induces large increases (up to 30 percent) in the optical density of bovine heart mitochondria incubated under conditions of low ionic strength (< approx. 0.01). The increases are associated with aggregation (sticking together) of the inner membranes and are little affected by changes in the energy status of the mitochondria. Virtually all of a number of other polyvalent cations tested and Ag(+) induce increases in mitochondrial optical density similar to those induced by Mg(2+), their approximate order of concentration effectiveness in respect to Mg(2+) being: La(3+) > Pb(2+) = Cu(2+) > Cd(2+) > Zn(2+) > Ag(+) > Mn(2+) > Ca(2+) > Mg(2+). With the exception of Mg(2+), all of these cations appear to induce swelling of the mitochondria concomitant with inner membrane aggregation. The inhibitors of the adenine nucleotide transport reaction carboxyatratyloside and bongkrekic acid are capable of preventing and reversing Mg(2+)-induced aggregation at the same low concentration required for complete inhibition of phosphorylating respiration, suggesting that they inhibit the aggregation by binding to the adenine nucleotide carrier. The findings are interpreted to indicate (a) that the inner mitochondrial membrane is normally prevented from aggregating by virtue of its net negative outer surface change, (b) that the cations induce the membrane to aggregate by binding at its outer surface, decreasing the net negative charge, and (c) that carboxyatractyloside and bongkrekic acid inhibit the aggregation by binding to the outer surface of the membrane, increasing the net negative charge.