The effects of the continuous administration of N,N-dimethyl-4-phenylazoaniline (DAB) on the activities and the inducibilities of some drug-metabolizing enzymes in rat liver.

(1) The effect of feeding a relatively low-protein diet containing 0.06% DAB for 29 weeks on the activity of DAB-azoreductase, nitroreductase (p-nitrobenzoic acid), N-oxidase (N,N-dimethylaniline), N-demethylase (DAB), cytochrome P-450, NADPH-cytochrome c reductase, beta-glucuronidase and arylsulphatase A were studied. Rapid decreases occurred in the activities of the first six enzymes, reaching minimal values at between 4 and 8 weeks. Activities then increased in all cases to control or nearly control levels. This rate of increase was least for cytochrome P-450. At 4 weeks azoreductase activity with the chemotherapeutic agent CB10-252 (I) as substrate was significantly higher than in control rats. Early increases occurred in the activities of beta-glucuronidase and arylsulphatase A and the activity of the latter never dropped below the control level. (2) An investigation was made of the differential effects of dye feeding on some of the enzyme activities in the two major liver lobes and differences were found. (3) The effect of phenobarbital (PB) pretreatment on the DAB-fed rats was studied at 4-week intervals. The activities of DAB-azoreductase and of nitroreductase increased throughout the whole period, while the activities of the lysosomal enzymes were decreased. (4) After feeding DAB for 4 weeks the effect of PB and 3-methylcholanthrene (MC) on the activities of DAB-azoreductase, CB10-252-azoreductase and components of the azoreductases-cytochrome P-450, NADPH-cytochrome c reductase, the CO-CB10-252-azoreductase was not induced by PB or MC, and CO did not inhibit its reduction. Its reduction depended only slightly on NADH. CO caused a greater relative decrease in the activity of DAB-azoreductase in dye-fed animals and also in animals following PB and MC pretreatment, implying a greater role of cytochrome P-450 in dye-fed animals.     

Characteristics of the induction of aldehyde dehydrogenase in rat liver

The activity of rat liver supernatant aldehyde dehydrogenase is increased by phenobarbital treatment in one selected strain (RR) but not in another strain (rr) of animals derived from randomally bred populations (Deitrich, Collins, and Erwin (1972) J. Biol. Chem., 247, 7232). Before 14 days of age, increased enzyme activity after phenobarbital treatment is minimal but between 30 and 60 days of age there is a maximal increase in activity after phenobarbital treatment. Using animals of this age, it was shown that both cycloheximide and actinomycin D block this response to phenobarbital. Phenobarbital treatment decreases heat stability of crude preparations of the enzyme from RR rats, but increases heat stability of the enzyme from rr animals.     

A cutin acid in Pinus sylvestris microspores

Nonacosan-10-ol (0.7%) and the cutin acid, 9,16-dihydroxyhexadecanoic acid (0.3%) are present in Pinus sylvestris microspores. The pollen coat hence has some features in common with leaf cuticles.     

In vivo metabolism of 3H-testosterone in adult male rats: effects of estrogen administration.

The metabolism of testosterone (T) was studied in normal adult male rats using a constant infusion of trace amounts of the 3H-steroid into a tail vein for 3 h in order to attain a state of equilibrium. Samples of plasma, liver, kidney, prostate, seminal vesicles and muscle were analysed for 3H-testosterone, 3H-5alpha-dihydrotestosterone (5alphaDHT) and 3H-5alpha-androstanediol (Adiol). When compared to the 3H-T level in plasma there were high levels of 3H-T in kidney and of 3H-5alphaDHT in prostate and seminal vesicles. Intraperitoneal estradiol valerate administration (100 mug/day) for 4 days decreased and 3H-5alphaDHT levels in the prostate and seminal vesicles. The estrogen administration increased the T metabolic clearance rate from 17.5 1/24 h/100 g body wt to 22.6 1/24 h/100 g body wt.     

Radioimmunoassay for plasma betamethasone 17-benzoate.

A sensitive radioimmunoassay for plasma betamethasone 17-benzoate has been developed. The antiserum used was obtained by immunizing rabbits with betamethasone 17-benzoate-21-hemisuccinate-bovine-serum-albumin conjugate. All of the endogenous steroids tested cross reacted less than 0.10%. A standard curve was established with a useful range from 0.05-5 ng. Reliability criteria were satisfactory. Measurement of plasma concentrations of betamethasone 17-benzoate was performed in patients and in rabbits following occlusive dressing of betamethasone 17-benzoate cream and gel base.     

Effect of in vitro zinc supplementation on HSPs expression and Interleukin 10 production in heat treated peripheral blood mononuclear cells of transition Sahiwal and Karan Fries cows

The changing climatic scenario with apprehended rise in global temperature is likely to affect the livestock adversely vis-à-vis production and reproduction. This has prompted more focus in addressing the unfavorable effects of thermal stress in livestock system. Presuming that the trace element zinc is indispensible for cellular antioxidant system and immune function, the present study was designed to investigate the effect of zinc treatment on heat stress alleviation and immune modulation in peripheral blood mononuclear cells (PBMC) of indigenous and crossbred transition cows. Twelve cows, six each of Sahiwal and Karan Fries (KF) in their second parity with confirmed pregnancy were selected for the experiment. The blood samples were collected at −21, 0 and +21 days in relation to expected date of calving. The experiment was carried out in vitro after isolating PBMC from whole blood. The 48 h cultured PBMC were subjected to assorted levels of exposures viz. 37 °C, 42 °C to impose heat stress and 42 °C+zinc to alleviate heat stress and modulate immunity. The PBMC viability was 86%, 69% and 78%, respectively. The mRNA expression of heat shock proteins (HSP 40, 70 and 90α) and Interleukin-10 (IL-10) production varied between the two breeds vis-à-vis days and levels of exposure. The mRNA expression of HSP40 and HSP70 was significantly (P<0.05) higher in Karan Fries than the Sahiwal cows. Both the breeds showed maximum expression of HSP on the day of parturition, more so in KF than Sahiwal. There was a significant (P<0.05) difference in the HSP mRNA expression at different levels of exposure. Zinc treatment to heat stressed PBMC caused a significant (P<0.05) down regulation of HSP. For immune status, anti-inflammatory cytokine, IL-10 in the culture supernatant was accessed. The IL-10 was significantly (P<0.05) higher in Karan Fries (168.18±14.09 pg/ml) than the Sahiwal cows (147.24±11.82 pg/ml). The IL-10 concentration was highest on the day of calving. Zinc treatment reduced the IL-10 concentration. From the study, it could be concluded that the zinc supplementation in heat stressed PBMC can ameliorate thermal stress and modulate immune response which can act as a model for reducing heat stress during the periparturient period in tropical livestock.     

A radioimmunoassay of plasma estradiol-17beta with the use of polyethylene glycol to separate free and antibody-bound hormone

A radioimmunoassay for plasma estradiol-17β was developed using polyethylene glycol to separate free from antibody-bound hormone. Specificity for estradiol-17β was achieved by a modified celite microcolunm procedure in which estradiol was.separated from interfering estrogens, including estrone. Using trace ³H-estradiol to monitor procedural losses, the method was shown to be sensitive and accurate. Intra- and inter-assay coefficient of variation of the method was 8.7 and 10.6%, respectively. Polyethylene glycol used for antibody precipitation appears to be a generally applicable method for steroid hormone radioimmunoassays. The simplicity, precision and rapid analysis, coupled with its lack of time dependence and ease in automation, makes this a convenient and practical method.     

The role of cytokines in the pathogenesis of cutaneous lupus erythematosus

Cutaneous lupus erythematosus (CLE) is an inflammatory disease with a broad range of cutaneous manifestations that may be accompanied by systemic symptoms. The pathogenesis of CLE is complex, multifactorial and incompletely defined. Below we review the current understanding of the cytokines involved in these processes. Ultraviolet (UV) light plays a central role in the pathogenesis of CLE, triggering keratinocyte apoptosis, transport of nucleoprotein autoantigens to the keratinocyte cell surface and the release of inflammatory cytokines (including interferons (IFNs), tumor necrosis factor (TNF)-α, interleukin (IL)-1, IL-6, IL-8, IL-10 and IL-17). Increased IFN, particularly type I IFN, is central to the development of CLE lesions. In CLE, type I IFN is produced in response to nuclear antigens, immune complexes and UV light. Type I IFN increases leukocyte recruitment to the skin via inflammatory cytokines, chemokines, and adhesion molecules, thereby inducing a cycle of cutaneous inflammation. Increased TNFα in CLE may also cause inflammation. However, decreasing TNFα with an anti-TNFα agent can induce CLE-like lesions. TNFα regulates B cells, increases the production of inflammatory molecules and inhibits the production of IFN-α. An increase in the inflammatory cytokines IL-1, IL-6, IL-10, IL-17 and IL-18 and a decrease in the anti-inflammatory cytokine IL-12 also act to amplify inflammation in CLE. Specific gene mutations may increase the levels of these inflammatory cytokines in some CLE patients. New drugs targeting various aspects of these cytokine pathways are being developed to treat CLE and systemic lupus erythematosus (SLE).     

Purine nucleoside phosphorylase (Np) in the mouse: Linkage relationship of Np-2 to esterase-10 (Es-10) and Np-1 on chromosome 14

An improved method for detecting four Np-1 (purine nucleoside phosphorylase) alleles in mouse erythrocytes by cellulose acetate electrophoresis is described. The previous linkage of Np-1 and Es-10 (esterase-10) was confirmed, with a map distance of 13.0±2.6 cM. Np-2 was detected by either specific activity assay or starch gel electrophoresis and shown to be linked to Es-10, 15.9 ± 3.1 cM, on chromosome 14. No recombinants between Np-1 and Np-2 were observed in 52 offspring, indicating either that these loci are either closely associated or that Np-2 represents simply a property of existing allelic products of the Np-1 locus.This research was supported by Medical Research Council of Canada grants to F.G.B. and F.F.S.     

Augmentation of Antigen-Specific Antibody Production and IL-10 Generation with a Fraction from Rooibos (Aspalathus linearis) Tea

Rooibos tea was extracted with boiling water. The aqueous extract was chromatographed in a Diaion HP20 column eluted stepwise with water, 25%, 50% and 75% (v/v) aqueous methanol, and 100% methanol. The water eluate (fraction A) showed an augmenting effect on anti-ovalbumin (anti-OVA) immunoglobulin M (IgM) production in OVA-stimulated murine splenocytes in vitro. Fraction A also showed a strong augmenting effect on interleukin-10 generation in murine splenocytes. Furthermore, continuous ingestion of fraction A was found to increase the anti-OVA IgM level in the sera of OVA-immunized mice.