Juxtaposition of N-myc and Ig kappa through a reciprocal t(6;12) translocation in a mouse plasmacytoma

In this study we examined the in vitro effects of alcohol on the proliferative responses of lymphocytes from healthy donors and AIDS patients to a recombinant fusion peptide, env-gag, corresponding to portions of the gp41 envelope (env) and internal core (gag) proteins of HIV. The effects of alcohol (ETOH) on the natural killer (NK) cell activities of lymphocytes from healthy donors and patients with AIDS were also investigated. Peripheral blood mononuclear cells from both normal donors and AIDS patients produced significant levels of lymphocyte proliferative responses to the HIV env-gag peptide; however, these responses were significantly higher in patients with AIDS, showing the specificity of the response. The env-gag-induced proliferative responses of lymphocytes from normal subjects were significantly suppressed when cultures contained only higher levels of ETOH (0.2% and 0.3%), whereas ETOH even at a lower level (0.1%) produced significant suppression of the env-gag-induced proliferation of lymphocytes only from AIDS patients. Direct addition of ETOH at concentrations of 0.1%, 0.2%, and 0.3% to cultures of lymphocytes from normal donors and NK target cells did not produce significant suppression of NK cell activities. However, ETOH at concentrations of 0.2% and 0.3% significantly suppressed the NK activities of lymphocytes from AIDS patients, and the suppressive effect was observed at all E:T cell ratios examined. Control peptide from the Escherichia coli expression vector did not produce any significant effect on lymphocyte proliferative responses or NK activity of both normal donors and AIDS patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alterations of the catalytic activities of drug-metabolizing enzymes in cultures of human liver slices

The pharmacokinetics of deramciclane (CAS 120444-78-8, EGIS-3886) was investigated in rabbits after i.v., p.o. and s.c. administration of 3 mg/kg 14C-phenyl-deramciclane. The plasma, concentration-time curves of total radioactivity, the parent compound (deramciclane) and its N-demethylated metabolite (EGIS-7056) were determined. The radioactivity level was measured by liquid scintillation technique while the concentration of the parent compound and its metabolite was determined by gas chromatography-mass spectrometry detection. The p.o. and i.v. studies were carried out on the same group of animals, while a separate group of rabbits was used for studying s.c. absorption. Deramciclane was readily absorbed after p.o. and s.c. treatment (tmax 1.0 to 1.4 h). The terminal elimination half-life (t1/2 beta) of the parent compound fell between 5.8 to 7.1 h, while that of the total radioactivity ranged from 21.6 and 26.0 h. The absolute bioavailability of deramciclane calculated from the AUC0-infinity values was found to be 43 and 60% after p.o. and s.c. treatment. The apparent volume of distribution (Vd) and the whole body clearance (Cl) of deramciclane after i.v. administration were 25.0 +/- 7.1 l/kg and 2.6 +/- 0.5 l/h/kg, respectively. The AUC0-infinity values of the parent compound varied between 4.6 and 7.9% of that of total radioactivity, suggesting that deramciclane was subjected to intensive metabolic conversion. The AUC0-infinity of N-desmethyl-deramciclane was 5.7%, compared to that of the parent compound after i.v. administration.     

Pregnancy in the chronically hypertensive patient

The majority of patients with mild chronic hypertension have successful pregnancy outcomes. Most perinatal morbidity is secondary to superimposed preeclampsia. Antihypertensive therapy does not appear to significantly affect pregnancy outcome, nor the incidence of superimposed preeclampsia in mild chronic hypertensives. The maternal and fetal risks are considerably higher for severe chronic hypertension and for those patients with target organ disease. These patients ideally should be counseled regarding their risks prior to pregnancy. Antihypertensive therapy should be instituted at diastolic pressures greater than or equal to 100 mm Hg.     

A new action of parathyroid hormone. receptor-mediated stimulation of extracellular acidification in human osteoblast-like SaOS-2 cells

The major physiological function of parathyroid hormone (PTH) is the maintenance of Ca2+/Pi homeostasis via the parathyroid hormone/parathyroid hormone-related protein receptor (PTHR) in kidney and bone. An important consequence of PTHR activation in bone is enhanced local acidification of the extracellular space. Agonist activation of some seven transmembrane-domain receptors increases the extracellular acidification rate (ECAR). We utilized microphysiometry to investigate PTH-stimulated, receptor-mediated increases in ECAR in human osteoblast-like SaOS-2 cells. PTH-(1-34) elicited a large, acute, dose-dependent increase in ECAR with an EC50 of about 2 nM. The PTH-induced increase in ECAR was specific to cells expressing the PTHR and was inhibited by PTHR antagonists. Rapid, partial, homologous desensitization of the PTH-induced increase in ECAR was observed. Incubation of SaOS-2 cells with 8-bromo-cyclic AMP neither mimicked nor abrogated the PTH effect, and PTH stimulated an acute increase in ECAR in cAMP-resistant SaOS-2 Ca#4A cells. Stimulation of ECAR by PTH was independent of transient increases in cytosolic free calcium. Both inhibition and down-regulation of PKC reduced the PTH-induced increase in ECAR. Inhibition of Na+/H+ exchange did not affect the PTH-induced ECAR response. We conclude that PTH caused a receptor-mediated, concentration-dependent, increase in ECAR, which was not dependent on the cAMP/PKA signaling pathway or the Na+/H+ exchanger but involved the action of PKC. Thus, acid production in bone, a physiologically important action of PTH, is not confined to osteoclasts as previously considered but is also mediated by osteoblasts.     

Nitric oxide inhibition in an ovine model of heart failure

1. The role of nitric oxide (NO) in congestive heart failure was investigated by studying the acute haemodynamic, hormonal and renal effects of N(G)-monomethyl-L-arginine (L-NMMA(, a nitric oxide inhibitor, given as incremental bolus doses in six sheep before (normal) and after induction of heart failure (HF) by rapid left ventricular pacing (LVoff+). 2. 6-NMMA caused significant initial dose-dependent rises in left ventricular systolic pressure, mean arterial pressure (MAP), peripheral resistance (PR) and left atrial pressure and declines in cardiac output in both normal and HF states (maximum response in 2-6 min). These responses were all but abolished when L-arginine was given concurrently with L-NMMA. The dose-response curve for the L-NMMA-induced rise in MAP was shifted to the right following LVP (P < 0.05), which is consistent with previous observations of blunted NO synthase activity in HF. A subsequent decline in MAP and PR to below prebolus levels was observed 30-60 min after L-NMMA administration in the paced state. No significant hormonal or renal effects were observed. 3. In conclusion, the present study confirms the important haemodynamic role played by endogenous NO in the normal state and demonstrates a blunted pressor response to NO inhibition in this model of heart failure.     

Uncoupling of stem cell inhibition from monocyte chemoattraction in MIP-1alpha by mutagenesis of the proteoglycan binding site

We have studied the role of proteoglycans in the function of Macrophage Inflammatory Protein-1 alpha (MIP-1alpha), a member of the proteoglycan binding chemokine family. Sequence and peptide analysis has identified a basic region within MIP-1alpha which appears to be the major determinant of proteoglycan binding and we have now produced a mutant of MIP-1alpha lacking the basic charges on two of the amino acids within this proteoglycan binding site. This mutant (Hep Mut) appears to have lost the ability to bind to proteoglycans. Bioassay of Hep Mut indicates that it has retained stem cell inhibitory properties but has a compromised activity as a monocyte chemoattractant, thus suggesting uncoupling of these two properties of MIP-1alpha. Receptor studies have indicated that the inactivity of Hep Mut on human monocytes correlates with its inability to bind to CCR1, a cloned human MIP-1alpha receptor. In addition, studies using proteoglycan deficient cells transfected with CCR1 have indicated that the proteoglycan binding site in MIP-1alpha is a site that is also involved in the docking of MIP-1alpha to the monocyte receptor. The site for interaction with the stem cell receptor must therefore be distinct, suggesting that MIP-1alpha utilizes different receptors for these two different biological processes.