The effect of hepatic enzyme-inducing antiepilepsy drugs (AEDs) on the clinical pharmacokinetics of tiagabine, a new AED, was studied in the steady-state condition. Patients with epilepsy entered this two-day study on a previously stable regimen of one to three enzyme-inducing drugs (phenytoin, phenobarbital, carbamazepine, and/or primidone) and tiagabine.HCl (24, 40, 56, or 80 mg daily). Patients were confined on both days, and serial blood samples were collected. Plasma tiagabine concentrations were determined by high-performance liquid chromatography; pharmacokinetic parameters were calculated using noncompartmental methods. Tiagabine pharmacokinetics were linear at all doses, as substantiated by the lack of significant differences among groups for dose-adjusted Cmax, Cmin, and AUC0-6. Some diurnal variation occurred, as evidenced by a statistically significant time effect for dose-adjusted AUC0-6. The effect was small, however, and possibly not clinically relevant. The harmonic mean half-lives of 3.8 to 4.9 h were remarkably constant across dosages and shorter than those of historical control subjects not taking enzyme-inducing AEDs suggesting that epilepsy patients not taking enzyme-inducing AEDs may require lower tiagabine.HCl doses to achieve the plasma levels observed in patients taking these drugs.

A major limitation on the therapeutic use of cytokine antagonists is that the amount of cytokine to be neutralized in vivo is not presently known. We previously reported that anti-interleukin-6 (IL-6) monoclonal antibody (MoAb) administered to a patient with multiple myeloma (MM) induced high amounts of IL-6 to circulate in the form of monomeric immune complexes. Based on this observation, the present study developed a new methodology to estimate daily IL-6 production in 13 patients with MM or renal cancer who received anti-IL-6 MoAb. Treatment was considered effective when the production of C-reactive protein (CRP) was inhibited. The production of this acute-phase protein by hepatocytes is dependent on the activation of IL-6 gp130 transducer. Inhibition of tumor proliferation was also evaluated in patients with MM. In 7 of 13 patients whose CRP production was completely inhibited (> 96%) and who showed some antitumoral effects, whole-body IL-6 production in vivo was less than 18 micrograms/d (median, 5.7 micrograms/d; range, 0.5 to 17.5 micrograms/d). In the other 6 patients, subtotal inhibition of CRP production and a lack of antitumoral response were associated with high IL-6 production (median, 180 micrograms/d; range, 18 to 358 micrograms/d). These in vivo observations were consistent with mathematical modeling that predicted that anti-IL-6 MoAb treatment would be efficient only in low IL-6 producers. These data indicate the difficulty of neutralizing IL-6 with a single anti-IL-6 MoAb in vivo and call for new strategies to avoid accumulation of IL-6 in the form of stable immune complexes.

Bupropion (BUP) may be less likely than other antidepressants to cause switches into mania and rapid cycling, suggesting utility in bipolar disorder. The combination of BUP with the mood-stabilizing anticonvulsants carbamazepine (CBZ) or valproate (VPA) is a strategy that might further lessen the risk of mania. CBZ induces, and to a lesser extent VPA inhibits the hepatic metabolism of various medications, but their effects on BUP have not been previously studied. Inpatients with mood disorders had pharmacokinetic profiles of BUP and metabolites assessed after single, oral, 150-mg doses of BUP while receiving placebo (N = 17) or during chronic blind CBZ (N = 12) or VPA (N = 5) monotherapy. CBZ but not VPA therapy decreased BUP peak concentrations (Cmax) by 87% (p < 0.0001) and 24-h area under the curve (AUC) by 90% (p < 0.0001), threohydrobupropion Cmax by 81% (p <0.0009) and AUC by 86% (p < 0.002), and erythropydrobupropion Cmax by 86% (p < 0.05) and AUC by 96% (p < 0.05). CBZ increased hydroxybupropion (H-BUP) Cmax by 71% (p < 0.007) and AUC by 50% (p < 0.09) and H-BUP AUC by 94% (p < 0.02). Thus, CBZ markedly decreased BUP and increased H-BUP concentrations, whereas VPA did not affect BUP but increased H-BUP concentrations. Further studies are required to determine how these differential effects of CBZ and VPA on BUP pharmacokinetics influence the tolerability and efficacy of combination therapies with these agents.

We investigated the clinical, histologic, and molecular responses of normal human skin to all-trans-retinol (ROL) application, compared to those induced by topical all-trans-retinoic acid (RA), and measured ROL-derived metabolites. Up to 1.6% ROL, 0.025% RA in vehicle (70% ethanol/30% propylene glycol), or vehicle alone were applied in a double-blind fashion to normal buttock skin and occluded for 4 d. ROL produced from none to only trace erythema, which was clinically and statistically insignificant, whereas RA induced a significant 3.7-fold increase in erythema score compared to vehicle (n = 10, p < 0.01). However, ROL induced significant epidermal thickening (1.5-fold at 1.6% ROL, p < 0.01), similar to RA (1.6-fold at 0.025% RA, p < 0.01), relative to the vehicle. ROL, compared with vehicle, also increased mRNA levels of cellular retinoic acid binding protein (CRABP-II) and cellular retinol binding protein (CRBP) genes as determined by Northern analysis (5-6-fold and 6-7-fold, respectively) and riboprobe in situ hybridization. CRABP-II and CRBP protein levels were also higher following ROL than vehicle treatment, as measured by ligand binding (3.2-fold, p < 0.001; n = 7) and Western analysis (3.6-fold, p < 0.003; n = 6), respectively. Epidermal retinyl ester (RE) content, measured after removal of stratum corneum, rose 240-fold (p < 0.005, n = 5) by 24 h of ROL occlusion. RA content, however, was undetectable or detectable only at trace amounts in all samples obtained at 0, 6, 24, and 96 h after ROL occlusion. Detectability of RA was not correlated with ROL treatment (compared to untreated normal skin, p = 0.86) or baseline skin ROL levels (average r = -0.1, p > 0.3). These data demonstrate that ROL application 1) produces trace erythema not significantly different from vehicle, whereas RA causes erythema; 2) induces epidermal thickening and enhances expression of CRABP-II and CRBP mRNAs and proteins as does RA; 3) causes marked accumulation of retinyl ester; and 4) does not significantly increase RA levels. Taken together, the data are compatible with the idea that ROL may be a prohormone of RA, because it produces changes in skin similar to those produced by RA but without measurable RA or irritation.

In view of the evidence linking plasma high density lipoprotein (HDL)-cholesterol levels to a protective effect against coronary artery disease and the widespread use of fibrates in the treatment of hyperlipidemia, the goal of this study was to analyze the influence of fibrates on the expression of apolipoprotein (apo) A-II, a major protein constituent of HDL. Administration of fenofibrate (300 mg/d) to 16 patients with coronary artery disease resulted in a marked increase in plasma apo A-II concentrations (0.34 +/- 0.11 to 0.45 +/- 0.17 grams/liter; P < 0.01). This increase in plasma apo A-II was due to a direct effect on hepatic apo A-II production, since fenofibric acid induced apo A-II mRNA levels to 450 and 250% of control levels in primary cultures of human hepatocytes and in human hepatoblastoma HepG2 cells respectively. The induction in apo A-II mRNA levels was followed by an increase in apo A-II secretion in both cell culture systems. Transient transfection experiments of a reporter construct driven by the human apo A-II gene promoter indicated that fenofibrate induced apo A-II gene expression at the transcriptional level. Furthermore, several other peroxisome proliferators, such as the fibrate, Wy-14643, and the fatty acid, eicosatetraynoic acid (ETYA), also induced apo A-II gene transcription. Unilateral deletions and site-directed mutagenesis identified a sequence element located in the J-site of the apo A-II promoter mediating the responsiveness to fibrates and fatty acids. This element contains two imperfect half sites spaced by 1 oligonucleotide similar to a peroxisome proliferator responsive element (PPRE). Cotransfection assays showed that the peroxisome proliferator activated receptor (PPAR) transactivates the apo A-II promoter through this AII-PPRE. Gel retardation assays demonstrated that PPAR binds to the AII-PPRE with an affinity comparable to its binding affinity to the acyl coA oxidase (ACO)-PPRE. In conclusion, in humans fibrates increase plasma apo A-II concentrations by inducing hepatic apo A-II production. Apo A-II expression is regulated at the transcriptional level by fibrates and fatty acids via the interaction of PPAR with the AII-PPRE, thereby demonstrating the pivotal role of PPAR in controlling human lipoprotein metabolism.

We investigated the pituitary thyrotrophin (TSH) response to repeated oral (non-pulsatile) thyrotrophin-releasing hormone (TRH) administration and potential modifying effects of dopamine antagonist treatment under conditions of constant peripheral thyroid hormone levels. In a randomized double-blind crossover trial, seven hypothyroid subjects, euthyroid on L-thyroxine, received 1 week each of oral TRH (40 mg, 12 hourly) plus metoclopramide (10 mg, 8 hourly) and TRH (40 mg, 12 hourly) plus placebo (one capsule, 8 hourly). At the beginning and end of each treatment period five samples of blood for estimation of serum TSH were taken over 1 h before ("baseline") and seven samples over 2 h after the treatment combination was given ("stimulated"). Serum free thyroxine, free triiodothyronine and prolactin levels also were measured. Mean log10 +/- SEM (log10 mIU/l) "baseline" serum levels TSH were -0.177 +/- 0.183 (median 0.345 mIU/l (untransformed); range (r) 0.03-10.11 mIU/l; first quartile (1q) 0.22 mIU/l; third quartile (3q) 2.48 mIU/l) before and 0.182 +/- 0.107 (median 1.385 mIU/l; r = 0.45-19.8 mIU/l; 1q = 0.9 mIU/l; 3q = 1.78 mIU/l) after 1 week of treatment (p < 0.02). There were no significant differences between oral TRH plus metoclopramide and oral TRH plus placebo. Peripheral thyroid hormone levels and the "stimulated" TSH response (expressed as area under curve after TRH and metoclopramide or placebo; min.log10 mIU/l) remained unchanged after 1 week. In the absence of changes in peripheral thyroid hormone levels, oral TRH over 1 week may not result in down-regulation of anterior pituitary thyrotrophs.2+ f2p4

Granulocyte adhesion to ischemic tissue, mediated in large part by beta 2 integrin receptors, is important in the pathophysiology of reperfusion injury. Acadesine, a drug that modulates adenosine levels in ischemic tissue, has been shown to reduce reperfusion injury in animal models of ischemia. The purpose of this study was to measure changes in granulocyte CD11b/CD18 in an in vitro assay and in an in vivo trial of acadesine administered during cardiopulmonary bypass to determine whether this agent might modulate up-regulation of this adhesion receptor. In vitro, whole blood was incubated with acadesine or control diluent, stimulated with N-formyl-methionyl-leucyl-phenylalanine, and granulocyte CD11b measured. Acadesine significantly (p < 0.01) inhibited N-formyl-methionyl-leucyl-phenylalanine-induced granulocyte CD11b up-regulation by a mean of 61%. In similar experiments, adenosine also inhibited N-formyl-methionyl-leucyl-phenylalanine-induced granulocyte CD11b up-regulation (p < 0.01). In vivo, 34 patients at our institution participating in a multicenter trial of acadesine during cardiopulmonary bypass were randomized to placebo, low-dose, or high-dose acadesine infusion perioperatively. Combining low- and high-dose treatment groups, there was significant (p = 0.05) inhibition of granulocyte CD11b up-regulation in patients receiving acadesine; granulocyte CD11b expression in the acadesine group peaked at 2.8 times baseline versus 4.3 for placebo. By contrast, monocyte CD11b up-regulation (peaking after cardiopulmonary bypass at 3 times baseline) was not affected by acadesine. Acadesine and adenosine inhibit up-regulation of granulocyte CD11b in vitro, and acadesine is capable of a similar inhibition during in vivo cardiopulmonary bypass. This inhibition may contribute to the ability of these agents to decrease in vivo reperfusion injury.

Twenty-one operable breast cancer patients were treated with interferon-beta (IFN-beta) at the dosage of 3 x 10(6) IU every other day for a median time of 16 days. Estrogen receptors (ER), progesterone receptors (PgR), labelling index (LI) and DNA ploidy were evaluated on tumour tissue obtained during diagnostic biopsy and surgery, before and after treatment respectively. The study showed a statistically significant rise of ER (18 out of 21 evaluable cases) (p = 0.04) and no influence on ploidy status (8/21) in all evaluable samples. We also noticed a rise of PgR (18/21) and a decrease of LI (10/21 cases), but they were not statistically significant. Moreover, in the patients in whom both determination of ER and LI was possible (10 cases), a significant inverse correlation between the differences pre- and post-treatment was observed (p = 0.016). These preliminary results induce us to study a greater number of patients with the aim to confirm the biological effects of IFN-beta on ER, to clarify the trend of the rise of PgR and the decrease of LI and to analyse the relationship between these parameters.

Growth deficiency is the most common secondary feature of osteogenesis imperfecta. It is unrelated to fracture history and appears to be due to the growth failure of the defective bony matrix. There are characteristic growth curves for different types of OI. We have been investigating the endocrine features of this disorder, in which the skeletal target tissue synthesizes defective matrix. We review the results of our evaluation of the growth hormone axis in 28 children with short stature and OI and of our pilot study to stimulate OI bone to increased growth rates. Our current focus is on the effect of growth hormone treatment on linear growth, bony mineral and bony matrix in OI.

IL-1 alpha and IL-1 beta are polypeptide hormones that exhibit a broad spectrum of beneficial and harmful biologic activities. Clinical trials designed to benefit from its stimulatory effects on human hematopoiesis and from its role in improving host defenses, are being currently conducted. Other in vivo studies, using IL-1 inhibitors with an attempts to block the detrimental effects of IL-1, are underway. Because of the multifunctional effects of IL-1 in human physiology and its pathogenetic role in several diseases, the capability to control the effects of IL-1 may prove to be a useful tool in medical practice.

Tumor necrosis factor (TNF) has a pivotal role in the pathogenesis of sepsis and septic shock. Suppression of its biosynthesis might therefore be one of the strategies in the treatment of sepsis. When peripheral white blood cells were stimulated with either E. coli lipopolysaccharide (LPS) or Staphylococcus aureus, pentoxifiline (PTX) inhibited TNF production. In contrast, only a moderate inhibitory effect was observed on the induction of interleukin 6 (IL-6). PTX inhibited not only the TNF production of monocytes, but also the TNF secretion of both granulocytes and unseparated whole blood. The in vitro TNF and IL-6 producing capacities were higher in septic patients (n = 31) than in healthy blood donors (n = 15). Administration of PTX (400 mg/day) to 20 of the septic patients resulted in TNF production similar to that found in healthy controls. It also subsequently led to an improvement of the clinical status classified by the APACHE II score. The soluble intercellular adhesion molecule-1 (sICAM-1) level was significantly higher in the sera of septic patients before PTX treatment (800-1200 ng/ml) than in normal individuals (50-150 ng/ml), but it decreased following PTX therapy. Cytofluorometric analysis revealed that the expression of ICAM-1 on stimulated mononuclear cells was inhibited by PTX. It is presumed that the suppressive effect of pentoxifylline on TNF production may be of clinical importance, improving the therapeutic strategies in septic syndrome.

Immunomodulatory effects of retinoids may be part of their anti-carcinogenic and anti-inflammatory properties. We studied the in vivo effects of retinoic acid (RA) on antigen-presenting activity of human epidermal Langerhans cells and on accessory cell activity of keratinocytes. Two skin sites from each volunteer were treated in vivo with 0.1% RA or vehicle, respectively, once a day for 4 d. RA-treated epidermal cell (RA-EC) alloantigen presentation to CD4+ T cells in each volunteer tested was consistently greater than that induced by vehicle EC. However, this increased antigen-presenting activity did not lead to autoreactive CD4+ T-lymphocyte proliferation. Elevated unfractionated epidermal antigen-presenting activity of RA-EC was not due to increased keratinocyte major histocompatibility complex (MHC) or intercellular adhesion molecule expression or to other keratinocyte accessory signaling, because incubation of CD1a-fluoroscence-activated cell sorter (FACS)-purified RA-EC inhibited alloantigen presentation, presumably through increased keratinocyte transforming growth factor-beta. By contrast, Langerhans cell function was upregulated; FACS-purified CD1a+ Langerhans cells derived from RA-EC displayed a markedly increased ability, relative to Langerhans cells from vehicle EC, to present alloantigen to T cells. Triple color flow-cytometric analysis of RA-EC and vehicle EC suspensions revealed that RA treatment did not modify the number of DR+ and CD1a+DR+EC, but did result in statistically significant increases in Langerhans cells expression of HLA-DR, CD11c, and CD1c. Another novel finding was that HLA-DR-dependent Langerhans cells antigen-presenting activity in both normal and RA-treated skin was completely blocked by anti-CD11c antibody. Thus, retinoid upregulation of antigen-presenting activity may be due to upregulation of Langerhans cell CD11c, as well as class II MHC. Upregulation of cutaneous immune responsiveness in human skin without autoreactivity has not (to our knowledge) been reported previously, and the Langerhans cell phenotypic and functional state achieved is distinct from previously reported states of Langerhans cell activation.

The binding of [3H]citalopram to the platelet 5-hydroxytryptamine (5-HT) transporter was measured in a group of healthy male drinkers of ayahuasca, a psychoactive sacrament indigenous to Amazonia, and a group healthy male controls. An increased number of binding sites (Bmax) in the platelets of ayahuasca drinkers was found, while the dissociation constant (Kd) remained the same for both groups. If indicative of neuronal 5-HT uptake activity, these results would suggest a decreased concentration of extracellular 5-HT, or a response to increased production and release of 5-HT. Such changes in 5-HT synaptic activity, in this case, should not be misinterpreted as an indication of developing neurological or psychiatric illness.

Gonadotropin levels were determined in 17 postmenopausal women before and after administering a single depot-dose of the GnRH agonist triptorelin. E2 levels of all samples were in the normal (low) postmenopausal range and no differences were found when the patients were grouped according to chronological age, or time after menopause. Pre-GnRH agonist levels of LH and FSH were in the normal (high) postmenopausal range. Two weeks after medication, LH and FSH had decreased to premenopausal levels (P < 0.0001). Eight weeks after medication, LH levels were still low whereas FSH levels had risen significantly again (P < 0.0001). Both LH and FSH levels, however, were still significantly below the serum concentrations before the administration of triptorelin (P < 0.0001). The pre-GnRH agonist level of FSH was significantly higher in women > 67 years old (P < 0.05), as compared to women < 67 years. Two weeks after medication both LH and FSH levels were significantly higher in women more than 15 years after menopause (P < 0.05), as compared to those < 15 years. The same was found for FSH in women > 67 years old. No further significant differences were noted. This study demonstrates a significant decrease of LH and FSH serum levels in postmenopausal women within two weeks after administration of a single depot-dose of the GnRH agonist triptorelin. After eight weeks, in contrast to premenopausal women, both LH and FSH, although rising, were still significantly suppressed.

Standard short-course regimens for tuberculosis are used worldwide with very few problems. Unfortunately, the emergence of multiple drug-resistant tuberculosis in many parts of the world is leading to a diversification of drug regimens and to the use of drugs that are more toxic per se and more likely to interact with others. In addition, the treatment of HIV/AIDS patients with tuberculosis or disease due to Mycobacterium avium-intracellulare complex (MAC) infection with new drugs and multidrug regimens has added to the problem of drug interactions, especially as such patients may often be receiving concomitant treatment for a range of bacterial, fungal and viral infections. In general, there are very few clinically significant interactions between the first-line antituberculosis drugs themselves, although problems of bioavailability, notably of rifampicin (rifampin), have been encountered in the manufacture of combination tablets. Of the first-line drugs used to treat tuberculosis, i.e. rifampicin, isoniazid and pyrazinamide, rifampicin is particularly likely to cause clinically significant drug interactions as it is a potent inducer of the cytochrome P450 enzyme group, which is involved in the metabolism of many drugs, in particular oral contraceptives, corticosteroids, oral anticoagulants and cyclosproin. The use of quinolones to treat multiple drug-resistant tuberculosis and AIDS-related MAC disease raises further problems of drug interactions as, in contrast to rifampicin, these drugs inhibit some cytochrome isoenzymes, leading to reduced metabolism of certain drugs.

As part of a multicenter randomized study 40 patients with chronic hepatitis C (HCV)-infection, 28 kryptogenic and 12 posttransfusional, were treated with recombinant interferon alfa (IFN alpha-2a) for 1 year in a dosage of 3 x 3 Mio. units per week versus dosis escalation after 8 and 16 weeks in serological non-responders. 36 of the 40 patients were followed over 3 years. The rate of patients with normalization of aminotransferases was 42% after two months of therapy, 28% at the end of treatment, 28% after 1 year and 23% after 3 years of follow-up. The polymerase chain reaction (PCR) for detection of HCV-RNA became negative after two months of treatment in 73%, at the end of therapy in 63%, after 1 year follow-up in 63% and after 3 years in 35%. All patients with persisting remission maintained HCV-RNA negative. Dosis escalation was realized in 8 patients without increase of responder rate. Antibodies against IFN alpha-2a developed in 4 (10%) patients without remarkable influence on the IFN-effect. Histological improvement at the end of treatment was observed in 61% including all patients with serological remission. The data support the prognostic relevance of the course of aminotransferases. If aminotransferases are not normalized during the first two months the treatment can be terminated. Persisting normalization of aminotransferases during 1 year after therapy and negative HCV-PCR result indicate maintaining remission.

Neutrophil-endothelial adhesion is the initiating event in neutrophil migration to areas of infection or injury. The binding of neutrophils to endothelium depends upon adhesive glycoproteins, of which the CD11/CD18 glycoproteins are the most important. Because of known upregulation of one of these adhesive glycoproteins (CD11b) during cardiopulmonary bypass (CPB) in humans, we evaluated CD11a, CD11b, and CD11c surface expression before, during, and after CPB in humans, with or without pre-CPB administration of a glucocorticoid (methylprednisolone). Fourteen patients were randomized into two groups: Group S received methylprednisolone (1 g intravenously) 5 min prior to CPB; Group N received no steroid. CD11b was significantly upregulated (P < 0.01) during, and 24 h after, CPB in Group N when compared with controls and Group S at similar time intervals, while in Group S no significant changes were found. Since interleukin-1, tumor necrosis factor, and endotoxin are known to upregulate neutrophil CD11b surface expression and are released during CPB in humans, while steroids are known to suppress the release of these cytokines, the authors conclude that the blunting effect by steroids on CD11b surface expression upregulation during and after CPB in humans is attributed to suppressed cytokine release.

Latent 2', 5'-oligoadenylate (2-5A) synthetase activity, bioactive 2-5A and RNase L activity were measured in extracts of peripheral blood mononuclear cells (PMBC) before and during a randomized, multicenter, placebo-controlled, double-blind study of poly(I)-poly(C12U) in individuals with chronic fatigue syndrome (CFS) as defined by the Centers for Disease Control and Prevention. The mean values for bioactive 2-5A and RNase L activity were significantly elevated at baseline compared to controls (p < .0001 and p = .001, respectively). In individuals that presented with elevated RNase L activity at baseline, therapy with poly(I)-poly(C12U) resulted in a significant decrease in both bioactive 2-5A and RNase L activity (p = .09 and p = .005, respectively). Decrease in RNase L activity in individuals treated with poly(I)-poly(C12U) correlated with cognitive improvement (p = .007). Poly(I)-poly(C12U) therapy resulted in a significant decrease in bioactive 2-5A and RNase L activity in agreement with clinical and neuropsychological improvements (Strayer DR, et al., Clin. Infectious Dis. 18:588-595, 1994). The results described show that poly(I)-poly(C12U) is a biologically active drug in CFS.