Elimination of IgE regulatory rat CD8+ T cells in vivo differentially modulates interleukin-4 and interferon-gamma but not interleukin-2 production by splenic T cells

Intraperitoneal immunization of Hooded Lister rats with a soluble antigen such as bee venom phospholipase A2 (PLA2), or ovalbumin (OVA) together with the toxic lectin, ricin, eliminates a population of early-activated CD8+ T cells which regulate IgE production. These early-activated CD8+ T cells are eliminated because they bear increased ricin-binding glycoproteins on their surface. This immunization regimen produces a vigorous and long-lived IgE response. The effect of this treatment on the capacity of splenic T cells to secrete interferon-gamma (IFN-gamma), interleukin-2 (IL-2) and to generate IL-4 RNA message was assessed. IFN-gamma production by phytohaemagglutinin (PHA)- or ionomycin and phorbol myristate acetate (PMA)-stimulated splenocytes or purified splenic T cells from animals immunized with antigen and ricin was substantially reduced as compared with animals which were given saline or antigen alone (P < 0.001 Student's t-test). At the height of the primary IgE response IFN-gamma production by PHA-stimulated splenocytes was positively correlated with the number of CD8+ T cells (r = 0.90, P < 0.001) and inversely related to the level of serum IgE (r = -0.77, P < 0.020); serum IgE was inversely related to the number of CD8+ T cells (r = -0.92, P < 0.001). The reduced capacity of spleen cells from ricin and antigen immunized rats to produce IFN-gamma was first seen 7 days after immunization. The fall in the ability of splenocytes to secrete IFN-gamma closely paralleled the rise in serum IgE. IL-2 was assayed using an IL-2-dependent cell line which responded to rat IL-2 but not IL-4. Production of IL-2 by splenocytes taken from rats immunized with ricin+antigen was not significantly different to that produced by comparable cells obtained from animals immunized with antigen alone or saline. However, the levels of IL-4 mRNA, detected in ionomycin and PMA-stimulated splenocytes using a quantitative polymerase chain reaction (PCR) procedure, were three- to fourfold higher in ricin and antigen immunized animals as compared with control animals. Following boosting with antigen and ricin the levels of IL-4 message detected increased a further three- to fourfold. These data show that the potentiated IgE response produced by immunization with antigen+ricin is associated with a decreased ability of splenocytes to produce IFN-gamma and an increased capacity to make IL-4.

Behavioural and biochemical evidence of the interaction of the putative antipsychotic agent, BMY 14802 with the 5-HT1A receptor

The behavioural and biochemical profile of the sigma ligand and putative antipsychotic agent, BMY 14802 (alpha-(4-fluorophenyl)-4-(5-fluoro-2- pyrimidinyl)-1-piperazine butanol) has been determined in the mouse and rat. In mice, pretreatment with BMY 14802 attenuated both amphetamine-induced hyperactivity and conditioned avoidance responding, consistent with its previously reported antipsychotic potential. In common with 5-HT1A receptor agonists or partial agonists, BMY 14802 induced (a) a dose-dependent hypothermia in mice; (b) aspects of the 5-HT behavioural syndrome in rats, (c) antagonised mescaline-induced head twitches in mice and (d) generalised to the 8-hydroxy-2-(di-n-propylamino)tetralin discriminative stimulus over the dose range of 3-15 mg/kg. BMY 14802 had appreciable affinity for the 5-HT1A receptor (pIC50 = 6.7 compared to 7.3 for sigma binding) and antagonised forskolin-stimulated adenylate cyclase activity with a pEC50 of 6.2, consistent with an agonist action at this receptor. The results support the involvement of 5-HT1A receptors, but not the sigma binding site, in the behavioural profile of BMY 14802.

New data on the pharmacokinetics of adriamycin and its major metabolite, adriamycinol

Twenty-two days after administration by intravenous bolus, of 50 mg of adriamycin to several patients we found concentrations of adriamycin and adriamycinol of the order of 100 pcg/ml. In theory, however, with a terminal half-life of 30 h, the plasma levels of adriamycin and adriamycinol should be close to 0.1 pcg/ml. Further pharmacokinetic investigation was therefore necessary. We have retained for this study nine male patients, aged between 53 and 69 years who received 25 to 50 mg of adriamycin by slow intravenous injection. The HPLC method permitted the detection of 50 pcg/ml of adriamycin and adriamycinol, with the possibility of monitoring their elimination during 120 h (and in one case during 160 h). The terminal half-lives of elimination estimated in 8 patients were respectively 110 +/- 52 h for adriamycin and 92 h 50 min +/- 43 h for adriamycinol. Surface ratios under adriamycinol curves against calculated adriamycin was 1.10 +/- 0.26. Plasma levels found during the To in certain patients correspond to the end of the drug elimination of the previous treatment. It is difficult with a half-life to 110 h to predict the effects of residual concentrations of adriamycin and adriamycinol.

Performance of cryptococcus antigen latex agglutination kits on serum and cerebrospinal fluid specimens of AIDS patients before and after pronase treatment

Cryptococcal antigen titers in 97 serum and 42 cerebrospinal fluid (CSF) specimens from 37 AIDS patients with culture-proven cryptococcal infection were determined with the Meridian kit (Meridian Diagnostics Inc., Cincinnati, Ohio) before and after treatment with pronase. The geometric mean titers before and after pronase treatment were 1:45 and 1:588 in serum and 1:97 and 1:79 in CSF, respectively. Only on serum (but not CSF) specimens after pronase treatment were (i) titers increased by 2 to 13 dilutions on 57% of the specimens, all of which had titers of less than or equal to 1:128 before pronase treatment, (ii) false-negative reactions on 27% of specimens before pronase treatment eliminated, all of which had titers from 1:4 to 1:4,096, (iii) prozone-like reactions (titer, less than or equal to 1:256) on 9% of the specimens before pronase treatment eliminated, and (iv) agglutination reactions on all specimens stronger and easier to interpret. Antifungal agents added to serum as well as freeze-thaw cycles did not change antigen titers in serum. After two separate tests, the same titers were obtained on 94% of 35 serum specimens that were treated with pronase and on 96% of 53 CSF specimens that were not treated with pronase. A total of 26 serum specimens and 28 CSF specimens from patients with no cryptococcal disease were negative before and after pronase treatment. The IBL kit (International Biological Labs Inc., Cranbury, N.J.) was compared with the Meridian kit on 41 serum specimens and 14 CSF specimens. Results from the two kits agreed on 54 and 68% of serum specimens and 86 and 93% of CSF specimens before and after pronase treatment, respectively. The IBL kit generally produced higher titers on specimens in disagreement and produced no prozone-like reactions. Routine pronase treatment of serum is recommended with the Meridian kit in order to eliminate false-negative and unclear agglutination reactions by producing a consistent interpretation of agglutination reactions. CSF specimens do not require pronase treatment. Titer results produced by the kits from the two different manufacturers varied considerably: the kits should not be used interchangeably for determining antigen titers in serum specimens.

The relation between organochlorine residues in animal feeds and residues in tissues, milk and eggs: a review

Tolerance levels for organochlorine pesticide in stockfeed have been set by legislation in Queensland. The purpose of this review was to derive accumulation ratios from trials which have involved feeding organochlorine pesticides to cattle, poultry and pigs. These ratios can be used with the maximum residue limits already established for food products from these animals to calculate maximum permissibleresidue levels in feed. It was concluded that the levels for aldrin and dieldrin should be reduced from 0.05 to 0.01 nig/kg and that a level for benzene hexachloride, other than the y isomer, of 0.01 mg/kg be included. In all other cases where information was available the levels set by legislation are already below those calculated from trial results.

Regulation of inactive renin secretion: studies with aprotinin

The kidney and plasma of many species contain both an active form of renin and an inactive, but activatable, form. The kallikrein inhibitor aprotinin suppressed acid-activation of rabbit plasma inactive renin but not activation of the form of inactive renin released by rabbit kidney cortex slices incubated in vitro. This suggests that inactive renin is structurally modified after secretion. An aprotinin-sensitive step appears to regulate inactive renin secretion. Aprotinin inhibited inactive, but not active, renin secretion by rabbit kidney cortex slices and selectively suppressed the elevated release of inactive renin produced in sheep by the converting enzyme inhibitor enalapril. In anaesthetised rats, aprotinin potentiated the increase in plasma renin produced by captopril.

Importance of phosphorus and nitrogen in the nutrition of grass seedlings growing in mulga soil

A pot experiment was conducted to compare the Importance of nitrogen and phosphorus fertilizers to seedling growth of four grasses on mulga soil. Two native species, Monachather paradoxa (mulga oats) and Digitaria ammophila (silky umbrella grass), and two exotic ones, Anthephora pubescens (wool grass) and Cenchrus ciliaris cv. Biloela (buffel grass), were tested. Digitaria and the two exotic grasses reacted similarly to applied phosphorus while Cenchrus utilized soil nitrogen more readily than the others. Phosphorus produced marked growth responses, increased the nitrogen and phosphorus contents of the plants, reduced the time between emergence and tillering and reduced root/shoot ratios. Nitrogen fertilizer produced no significant responses and actually retarded very early seedling growth. There were no nitrogen x phosphorus interactions.