Hypertriglyceridemia is a metabolic complication of retinoid therapy. In this study, we analyzed whether retinoids increase the expression of apo C-III, an antagonist of plasma triglyceride catabolism. In men, isotretinoin treatment (80 mg/d; 5 d) resulted in elevated plasma apo C-III, but not apo E concentrations. In human hepatoma HepG2 cells, retinoids increased apo C-III mRNA and protein production. Transient transfection experiments indicated that retinoids increase apo C-III expression at the transcriptional level. This increased apo C-III transcription is mediated by the retinoid X receptor (RXR), since LG1069 (4-[1-(5,6,7,8-tetrahydro-3,5,5,8, 8-pentamethyl-2-naphtalenyl)ethenyl]benzoic acid), a RXR-specific agonist, but not TTNPB ((E)- 4-[2-(5,6,7,8-tetrahydro-5,5,8, 8-tetramethyl-2-naphtalenyl)propenyl]benzoic acid), a retinoic acid receptor (RAR)-specific agonist, induced apo C-III mRNA in HepG2 cells and primary human hepatocytes. Mutagenesis experiments localized the retinoid responsiveness to a cis-element consisting of two imperfect AGGTCA sequences spaced by one oligonucleotide (DR-1), within the previously identified C3P footprint site. Cotransfection assays showed that RXR, but not RAR, activates apo C-III transcription through this element either as a homo- or as a heterodimer with the peroxisome proliferator-activated receptor. Thus, apo C-III is a target gene for retinoids acting via RXR. Increased apo C-III expression may contribute to the hypertriglyceridemia and atherogenic lipoprotein profile observed after retinoid therapy.

IL-12 has significant antitumor activity in mice that may be mediated by CD8(+) T cells. We show in this report that repeated subcutaneous injections of IL-12 in patients with cancer resulted in the selective expansion of a subset of peripheral blood CD8(+) T cells. This T cell subset expressed high levels of CD18 and upregulated IL-12 receptor expression after IL-12 treatment in vivo. In normal subjects, these CD3(+)CD8(+)CD18(bright) T cells expressed IL-12 and IL-2 receptors and adhesion/costimulatory molecules to a greater degree than other CD8(+) and CD4(+) T cells. They appeared morphologically as large granular lymphocytes, although they did not express NK cell markers such as CD56. In addition, CD8(+)CD18(bright) T cells were almost exclusively T cell receptor (TCR) alphabeta+, and exhibited a TCR Vbeta repertoire that was strikingly oligoclonal, whereas the Vbeta repertoire of CD18(dim) T cells was polyclonal. Although CD8+CD18(bright) T cells demonstrated little functional responsiveness to IL-12 or IL-2 alone in vitro, they responded to the combination of IL-12+IL-2 with strong IFN-gamma production and proliferation and enhanced non-MHC-restricted cytolytic activity. In contrast, CD18(dim) T cells were not activated by IL-12 or IL-2, alone or in combination. These findings demonstrate that CD8+CD18(bright) T cells are a unique population of peripheral blood lymphocytes with features of both memory and effector cells that are capable of TCR-independent activation through combined stimulation with IL-12+IL-2. As this activation results in IFN-gamma production and enhanced cytolytic activity, these T cells may play a role in innate as well as acquired immunity to tumors and infectious pathogens. Additional studies will be necessary to determine whether CD8+CD18(bright) T cells mediate the antitumor effect of IL-12 or IL-2 administered to cancer patients, and if so, whether maximal activation of these T cells with the combination of IL-12+IL-2 in vivo can augment the clinical effectiveness of these cytokines.

The time-course of CD25 (the 55-kD/alpha subunit of the interleukin-2 (IL-2) receptor) expression on CD4+ T lymphocytes, and serum levels of soluble IL-2 receptors (sIL-2R) and IL-2 were evaluated in relapsing-remitting multiple sclerosis (RRMS) patients treated with interferon beta-1b (IFNbeta1b). Peripheral blood samples were collected before therapy (T0), and 1 (T1), 2 (T2), 3 (T3), 6 (T4), and 12 (T5) months after therapy initiation. While at T1 and T2, half the patients showed an increased number of circulating CD4+ CD25+ lymphocytes and an up-regulation of CD25 expression, at T3 this T-cell subset was significantly reduced in all the patients. From T4 to T5, however, the progressive return to pretreatment values was observed. Serum sIL-2R levels were not significantly affected by IFNbeta1b at any time point. IL-2 was detected in only a few patients at T0, and never at T1 to T5. The transient up-regulation of CD25+ expression that occurred in about 50% of the patients may explain the unchanged relapse rate observed during the first 2 to 3 months after starting IFNbeta1b therapy. Our study demonstrates that IFNbeta1b down-regulates CD25 expression in vivo. This effect, however, was observed only after 3 months of therapy, and was followed by the return to pretreatment values after 6 to 12 months. Taken all together, our findings suggest that IFNbeta1b only transiently affects CD25 expression in vivo, and that this effect cannot account for the reported long-lasting beneficial action of IFNbeta1b on RRMS.

Animal and postmortem studies indicate that neuroleptic therapy may induce D2 dopamine receptor up-regulation in the basal ganglia.

HP 228 is a synthetic heptapeptide analog of alpha-MSH that attenuates the production and release of inflammatory cytokines. The purpose of this study was to define HP 228's effects, alone and in combination with morphine, on resting ventilation and the ventilatory response to hypoxia and hypercarbia. Six healthy nonsmoking young adult males completed the four-session experiment. Subjects first underwent an initial training session. During subsequent sessions, each subject was tested for the respiratory effects of intravenous HP 228 (30 microg/kg), morphine (0.15 mg/kg), or HP 228 (30 microg/kg) plus morphine (0.15 mg/kg) in a double-blind placebo-controlled randomized balanced within-subjects experimental design. Sessions began with baseline measurement of resting ventilation, oxygen consumption, the isocapnic hypoxic ventilatory response (HVR), and normoxic hypercapnic ventilatory response (HCVR). A second set of respiratory measurements were obtained 10 min after completion of HP 228 or placebo infusion. Morphine or placebo was then administered and ventilatory responses were determined 15 and 40 min postinfusion. HP 228 produced cutaneous flushing, but had no significant effect on respiration or hemodynamics. Morphine significantly decreased metabolism, resting ventilation, and hypoxic and hypercarbic ventilatory responsiveness, independent of prior HP 228 administration. A seventh subject experienced a significant cardiac arrhythmia upon exposure to hypoxia after receiving both HP 228 and morphine and was withdrawn from further study. In conclusion, in this early Phase I clinical trial, HP 228 was found to neither depress ventilation nor augment morphine-induced respiratory depression in healthy young males.

The influence of coronary artery bypass grafting (CABG) on spontaneous and lipopolysaccharide (LPS)-stimulated release of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, and IL-10 as well as its modulation by pentoxifylline (PTF) were studied in a prospective, randomized, double-blinded study. 12 patients undergoing elective CABG were randomly assigned to receive either saline or PTF (1 mg/kg as a loading dose followed by 1 mg/kg/h) intraoperatively. Blood samples were obtained (A) preoperatively, (B) 20 min after CABG, and (C) 24 h after CABG. Cytokine plasma levels as well as LPS-stimulated cytokine secretion were measured in a whole blood culture system ex vivo and correlated with mRNA expression in peripheral blood mononuclear cells. In addition, the dose-response characteristics of modulation of the cytokine response by PTF were studied in cultured whole blood in vitro. Plasma IL-6 and IL-10-levels were significantly elevated after CABG, whereas neither TNF-alpha nor IL-1beta were detectable. In contrast to the spontaneous release of IL-6 and IL-10, the expression of all cytokines studied was significantly reduced upon ex vivo LPS stimulation early after CABG. Proinflammatory cytokine response upon LPS stimulation was restored 24 h after CABG for the group mean, however, with substantial interindividual heterogeneity. Therapeutic doses of PTF in vitro attenuated LPS-induced TNF-alpha (-50.5%) and most notably IL-10 (-83.9%) release, whereas IL-1beta was even increased (+45.7%). However, application of PTF during CABG neither inhibited the spontaneous production of IL-10 nor modulated cytokine production ex vivo. These results suggest a biphasic response of stimulated peripheral blood mononuclear cell cytokine gene expression during CABG with an initial tolerance to LPS stimulation. The application of PTF during CABG in doses that are primarily based on its use in occlusive arterial disease do not seem to modulate the release of the cytokines studied.

We have previously demonstrated that a single dose of oral prednisolone but not single doses of inhaled fluticasone had facilitatory effects on lymphocyte beta2-adrenoceptor (AR) function. To address possible differences in steady-state time-course, the aim of this study was to determine if repeated dosing with inhaled fluticasone would have facilitatory effects on lymphocyte beta2-AR. Plasma cortisol was also evaluated as a measure of systemic bioactivity.

Both single and multiple dose bioequivalence studies are required to assess the quality of modified release formulations of drugs. In bioequivalence studies of drugs with enzyme autoinducing properties such as carbamazepine (CBZ), the standard multiple dose study design must be modified to guarantee equivalence of drug elimination. This problem was considered with regard to carbamazepine 400 retard AWD (test) whose bioavailability relative to a listed reference (Tegretal 400 retard) was studied in 2 randomized, open, crossover studies both with 18 healthy volunteers of Caucasian origin (20-36 years, 61.5-92 kg, 172-195 cm). The single dose study was done with 400 mg CBZ. Serum concentration time profiles of CBZ and its active metabolite CBZ-10,11-epoxide were determined until 144 h after administration. The multiple dose study was performed with 400 mg CBZ b.i.d. for 15 days (first 2 days: 200 mg b.i.d.) followed by a 7-day study with the alternative investigational product. 24-hour serum concentration time profiles of CBZ and its metabolite were measured on days 15 and 22 of the study. The quantitative drug analysis was done with an HPLC method the quality of which fulfilled the requirements of bioequivalence studies. Test was considered bioequivalent to reference with regard to the extent of absorption, if the 90% confidence intervals of the AUC0-infinity ratio (single dose) and AUC0-24h ratio (multiple dose) were within the range of 0.80-1.25, and with regard to rate of absorption if the 90% confidence intervals of the Cmax/AUC ratio (single dose) or AUCF0-24h ratio were within 0.70-1.43. The point estimators (90% confidence limits) of the AUC ratio (test/reference) of CBZ were 0.979 (0.94, 1.02) for the single and 1.01 (0.947, 1.076) for the multiple dose comparison. The point estimator (90% confidence limits) of the Cmax/AUC ratio was 0.989 (0.959, 1.020) and of the AUCF0-24h ratio 1.066 (0.937, 1.212). There were no circadian time differences in any pharmacokinetic parameter.

We have studied the expression of the gene encoding the epsilon heavy chain of IgE in nasal B cells of hayfever patients. We developed probes to detect transcripts of the epsilon germ-line gene and the rearranged gene by in situ hybridization of biopsy sections from the nasal mucosa. We compared tissue from hayfever patients out of season with that of normal controls, and also of hayfever patients treated with topical corticosteroid (fluticasone propionate) or placebo for 6 weeks and then challenged with antigen. epsilon chain mRNA was expressed in an unexpectedly high proportion of nasal B cells of both hayfever patients and normal subjects. However, although similar numbers of B cells were found in both groups, the proportion of cells that express epsilon chain mRNA was several times higher in the hayfever patients. No transcripts of the epsilon germ-line gene were detected in either group before allergen challenge. When hayfever patients were administered antigen locally, early (10-30 min) and late (1-24 h) symptoms ensued. After 24 h, coincident with an increase in the number of cells expressing mRNA for IL-4 in the tissue, epsilon germ-line gene transcripts appeared in the nasal B cells. The induction by allergen of IL-4 mRNA and epsilon germ-line gene transcripts was suppressed by fluticasone propionate treatment. Our results suggest that local IgE synthesis and cytokine regulation of heavy chain switching to IgE occur in the nasal mucosa.

On the basis of previous animal studies, we hypothesized that dexamethasone may reduce the expression of L-selectin on neutrophils and lymphocytes in healthy men.

The effects of rhG-CSF administration on fMLP-induced neutrophil CD11b and CD18 upregulation were studied in nine patients suffering from intermediate and high grade non-Hodgkin's lymphomas. Blood samples were obtained before recombinant human granulocyte colony-stimulating factor (rhG-CSF) administration and 24 hrs after rhGSF interruption. The growth factor was administered subcutaneously for five days in a dosage of 5 microg/Kg/day. Nine normal subjects were studied as controls. Five patients showed an impaired baseline CD11b and CD18 upregulation, which was corrected by rhG-CSF therapy. Four patients showed a normal baseline CD11b and CD18 upregulation, but this function was reduced by rhG-CSF therapy. All patients showed a normal baseline fMLP-induced luminol-enhanced chemiluminiscence and significantly increased chemiluminescence values after rhG-CSF administration. We conclude that, while in some patients rhg-CSF is able to improve neutrophil CD11b and CD18 upregulation in response to chemotactic agents, in other patients a decrease of this function can occur, maybe due to a relative immaturity of the circulating neutrophils induced by rhG-CSF.

Until now the effects of beta-adrenergic agonists have largely been ascribed to their ability to induce intracellular formation of cyclic adenosine monophosphate. Recently evidence has been accumulating that at least some beta1 and beta2-adrenoceptor effects may be mediated by nitric oxide (NO). Based on these studies, we hypothesized that the beta-adrenoceptor mediated increase of von Willebrand factor and factor VIII-activity (FVIII:C) in plasma during exercise, is caused by an NO-dependent mechanism.

Interleukin-12 (IL-12) is a key regulator of cell-mediated immunity that has therapeutic potential in cancer and infectious disease. In a previous Phase 1 dose escalation study of a single test dose of recombinant human IL-12 (rhIL-12) followed 14 days later by cycles of five consecutive daily intravenous injections every 3 weeks, we showed that a dose level up to 500 ng/kg could be administered with acceptable levels of safety. Based on these results, a Phase 2 study was conducted. In the Phase 2 study, however, administration of rhIL-12 at this same dose level resulted in severe toxicities with some patients unable to tolerate more than two successive doses. Of the 17 patients receiving rhIL-12 in the Phase 2 study, 12 patients were hospitalized and two patients died. A thorough scientific investigation to determine the cause of this unexpected toxicity failed to identify any difference in the drug products used or the patient populations enrolled in the Phase 1 and Phase 2 studies that could have accounted for the profound difference in toxicity. The focus of the investigation therefore shifted to the schedule of rhIL-12 administration. We determined that a single injection of rhIL-12 2 weeks before consecutive dosing included in the Phase 1 study, but not in the schedule of administration in the Phase 2 study, has a profound abrogating effect on IL-12-induced interferon-gamma (IFN-gamma) production and toxicity. This observation of schedule-dependent toxicity of IL-12 has been verified in mice, as well as nonhuman primates. In this regard, a single injection of IL-12 before consecutive daily dosing protected mice and cynomolgus monkeys from acute toxicity including mortality and was associated with an attenuated IFN-gamma response. Because of this unique biologic response, careful attention to the schedule of administration is required to assure safe and effective clinical development of this highly promising cytokine.

In this study of 31 patients with coronary bypass surgery, we used flow cytometry to compare heparin-coated and noncoated cardiopulmonary bypass systems on leukocyte activation. We found significant differences between the groups during bypass, with activation of the complement system, measured as elevated levels of C3a desArg, upregulation of granulocyte beta2 integrin (CD11b), and a loss of circulating monocytes when noncoated systems were used. In both groups an early increase in the monocyte cell surface CD62L expression was obvious while the percentage of human leukocyte antigen (HLA)-DR positive monocytes did not alter. The morning after the operation, leukocytosis was present, together with a highly significant reduction in the monocyte expression of CD11b and HLA-DR, indicating the recruitment to the peripheral blood of cells with altered phenotypes. This alteration in phenotype on potent inflammatory cells may be one part of the impaired function of the immunological system reported after major surgery.

This study was conducted to determine whether vigabatrin affects in vivo indices of hepatic microsomal enzyme activity and the pharmacokinetics of steroid oral contraceptives in healthy subjects.

Interferon beta-1b reduces clinical exacerbations and disease activity in multiple sclerosis as shown by magnetic resonance imaging, but the mechanism of action is unknown. We investigated the correlation between the levels of soluble adhesion molecules and a reduction in contrast-enhancing lesions on gadopentetate dimeglumine magnetic resonance images after treatment with interferon beta-1b. We determined levels of soluble vascular cell adhesion molecule-1, intercellular adhesion molecule-1, E-selectin, L-selectin, and tumor necrosis factor receptor (60 kd) in monthly serum samples from patients with definite multiple sclerosis before and during treatment with interferon beta-1b. The level of soluble adhesion molecules was correlated with the number of newly enhancing lesions on monthly contrast-enhanced images. Levels of soluble vascular cell adhesion molecule during treatment were significantly increased compared to control or pretreatment values. The median levels (ng/ml) of this adhesion molecule were 580.3 (range; 373.0-640.7) for the healthy subjects, and 551.4 (489.7-875.5) for patients prior to treatment and 847.9 (591.5-1,232.9) during treatment. Levels of the other soluble adhesion molecules and soluble tumor necrosis factor receptor were not significantly changed during treatment. The increase in soluble vascular cell adhesion molecule correlated with a decrease in the number of contrast-enhancing lesions on magnetic resonance images. These data suggest a novel mechanism of action for interferon beta-1b by direct interference with the adhesion cascade, which may prevent activated T cells from trafficking into the central nervous system.

To explore the clinical implication of reversal of multidrug resistance (MDR) by cyclosporin A (CsA) in refractory and relapsed acute leukemias.

Triazolam is metabolized predominantly by cytochrome P450 3A4 (CYP3A4). Rifampin (rifampicin) is a potent inducer of CYP3A4 and it is known to markedly reduce plasma concentrations and effects of drugs such as midazolam. The possible interaction between rifampin and triazolam was examined in this study.

Although increased deposition of collagen proteins has been described after myocardial infarction (MI), little is known of time-dependent transcriptional alteration of specific cardiac collagen sub-types as well as the degradative mechanisms for cardiac collagens in right and left ventricular myocardium remote to large left ventricular infarction. We sought to study collagen mRNA abundance and the deposition of specific collagen subtypes in noninfarcted left and right rat heart muscle at different times after MI. We also assessed the activity of different myocardial matrix metalloproteinases (MMP) using zymography to gain some information about degradative pathways for collagen. Furthermore, we assessed passive compliance properties of the right ventricle in experimental hearts. Finally we investigated the role of the renin angiotensin system in the collagen gene expression by administration of an angiotensin converting enzyme (ACE) inhibitor (ramipril) and an angiotensin II receptor type I antagonist (losartan) in experimental animals. We observed that the mRNA abundance of types I and III collagen were increased 3 days after myocardial infarction in both viable left and uninfarcted right ventricular tissues, that they peaked at 7-14 days, and were maintained at relatively high levels in the 28 and 56 days experimental groups. Stiffness of the right ventricular myocardium was significantly increased in the 56 days experimental group when compared to that of control values. These findings correlated with increased immunohistochemical staining patterns of different collagen species in the surviving right (and left) cardiac interstitium of 14, 28, and 56 day experimental cardiac groups. The elevation of fibrillar collagen mRNA abundance in noninfarcted muscle from ventricular chambers was not significantly altered after treatment of experimental animals with ramipril and losartan for up to 14 days. MMP activity was increased in viable left ventricle at 14, 28 and 56 days and at 14 days in the right ventricle in experimental animals when compared to controls. These results indicated that (1) activation of transcription of collagen types I and III gene occurs in acute and chronic MI, and that fibrillar collagen proteins are deposited in the noninfarcted cardiac interstitium after a lag period relative to increased corresponding mRNA abundance; (2) an increase in MMP activity in chronic experimental hearts indicates that increased collagen deposition may be due to an increment in collagen synthesis rather by reduced degradation of collagen, and that MMP activation may be important in remodeling of the noninfarcted cardiac stroma; (3) an increase of right ventricular stiffness was associated with increased deposition of collagen; (4) as losartan treatment is not associated with any normalization of elevated collagen mRNA abundance, the upregulation of collagen gene expression in this model is not mediated by AT1 receptor; and (5) the reduction of cardiac fibrosis mediated by ACE inhibition and losartan treatment may reside at the post-translational level in cardiac collagen metabolism.

During the international placebo-controlled trial on the efficacy of interferon-gamma (IFN-gamma) in chronic granulomatous disease (CGD), 19 patients entered the study via our Institute. One patient stopped treatment shortly thereafter. RNA was purified from the mononuclear cells of the remaining 18 CGD patients before and during this placebo-controlled trial. The mRNA levels for the NADPH oxidase components were subsequently analyzed. Compared with the placebo-treated CGD patients, the mRNA levels for p47-phox were significantly increased in the IFN-gamma-treated CGD patients (P < 0.002). No significant changes were observed in the mRNA levels of the other oxidase components. These findings are in agreement with observations in vitro and indicate that IFN-gamma is active on the NADPH oxidase in vivo as well. However, it remains questionable whether these effects in vivo can explain the observed reduction of infections in these patients.