Bioavailability of moclobemide from two formulation tablets in healthy humans.

A ,,sine qua non" requirement for a generic formulation to be admitted for a medical use is to provide bioavailability studies in healthy subjects. Therefore, those studies were performed for 150 mg moclobemide tablets (Jelfa, Poland) versus 150 mg Aurorix (Hoffmann la Roche) reference tablets. An open-label, two-phase crossover study was conducted with 10 healthy subjects. Pharmacokinetic parameters (AUC, ke, t1/2, Cmax, tmax, tlag, V/f, Cl/f) obtained at the same time for moclobemide were supposed to be confronted with the literature data available for healthy volunteers. The plasma moclobemide levels as a function of time were calculated according to either an open one-compartment body model with lag time of absorption or non-compartmental method for calculation of bioavailability using Phoenix WinNonlin 8.0 software. For those reasons a suitable HPLC method was worked out. Carbamazepine was proposed as an internal standard and ammonia as well as Na2HPO4 as alkalizing agents for the mobile phase and the liquid-liquid extraction of moclobemide from human blood plasma, respectively. Basic pharmacokinetic parameters of moclobemide obtained in the paper are essentially equal to the literature data for the healthy subjects. However, bioavailability parameters (AUC0→t, AUC0→∞, Cmax, tmax) were greater for moclobemide tablets (Jelfa) if compared to Aurorix tablets (Roche) by more than 20 %. Furthermore, the extent of bioavailability (110.6 %) for the generic moclobemide tablets if compared to Aurorix tablets is not significantly different. It seems to us that the number of subjects should be increased from 10 to 24 to help to clarify that inconsequence.

Bioavailability of propylthiouracil from two formulation tablets.

Bioavailability studies were performed for 50 mg propylthiouracil tablets (Jelfa, Poland) versus 50 mg propycil tablets (Solvay, Germany). An open-label, two-phase, crossover study was conducted with 15 healthy subjects. All subjects were randomly assigned a drug assignment number from I to XV, which was used throughout the experimental period. Dosing periods for both formulation tablets: Propylthiouracil, Jelfa vs. Propycil, Solvay were separated by at least 7 days washout period. Following single dose drug administration, venous blood samples were obtained at the required times for 12 h and the drug serum levels were determined by HPLC and used for PK analysis. PK parameters were calculated by the computer program TopFit 2.0. HPLC chromatograms show retention times for propylthiouracil and methylthiouracil (internal standard) of 5.97 and 2.75 min, respectively at 20 °C, providing adequate separation from each other and from endogenous serum components. Pharmacokinetic parameters for both tablets were not significantly different. Serum concentration-time profiles are superimposed for the above tablets according to an open one-compartment body model. EBA for Propythiouracil Jelfa tablets vs. Propycil tablets was 96.8%, and not significantly different. Some authors applied a two-compartment body model for the calculation of propylthiouracil pharmacokinetic parameters, which approach is not rational according to our data.

Heavy metals in agricultural soils of the European Union with implications for food safety.

Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of the food chain. However, the quality of soil resources as defined by their potential impact on human health by propagation of harmful elements through the food chain has been poorly studied in Europe due to the lack of data of adequate detail and reliability. The European Union's first harmonized topsoil sampling and coherent analytical procedure produced trace element measurements from approximately 22,000 locations. This unique collection of information enables a reliable overview of the concentration of heavy metals, also referred to as metal(loid)s including As, Cd, Cr, Cu, Hg, Pb, Zn, Sb. Co, and Ni. In this article we propose that in some cases (e.g. Hg and Cd) the high concentrations of soil heavy metal attributed to human activity can be detected at a regional level. While the immense majority of European agricultural land can be considered adequately safe for food production, an estimated 6.24% or 137,000km(2) needs local assessment and eventual remediation action.

Enhanced mobilization of the bone marrow-derived circulating progenitor cells by intracoronary freshly isolated bone marrow cells transplantation in patients with acute myocardial infarction.

Autologous bone marrow cell transplantation (BMCs-Tx) is a promising novel option for treatment of cardiovascular disease. We analysed in a randomized controlled study the influence of the intracoronary autologous freshly isolated BMCs-Tx on the mobilization of bone marrow-derived circulating progenitor cells (BM-CPCs) in patients with acute myocardial infarction (AMI). Sixty-two patients with AMI were randomized to either freshly isolated BMCs-Tx or to a control group without cell therapy. Peripheral blood (PB) concentrations of CD34/45(+) - and CD133/45(+)-circulating progenitor cells were measured by flow cytometry in 42 AMI patients with cell therapy as well as in 20 AMI patients without cell therapy as a control group on days 1, 3, 5, 7, 8 and 3, 6 as well as 12 months after AMI. Global ejection fraction (EF) and the size of infarct area were determined by left ventriculography. We observed in patients with freshly isolated BMCs-Tx at 3 and 12 months follow up a significant reduction of infarct size and increase of global EF as well as infarct wall movement velocity. The mobilization of CD34/45(+) and CD133/45(+) BM-CPCs significantly increased with a peak on day 7 as compared to baseline after AMI in both groups (CD34/45(+): P < 0.001, CD133/45(+): P < 0.001). Moreover, this significant mobilization of BM-CPCs existed 3, 6 and 12 months after cell therapy compared to day 1 after AMI. In control group, there were no significant differences of CD34/45(+) and CD133/45(+) BM-CPCs mobilization between day 1 and 3, 6 and 12 months after AMI. Intracoronary transplantation of autologous freshly isolated BMCs by use of point of care system in patients with AMI may enhance and prolong the mobilization of CD34/45(+) and CD133/45(+) BM-CPCs in PB and this might increase the regenerative potency after AMI.

Biopharmaceutical characterization of some new papaverine decomposition products.

2,3,9,10-Tetramethoxy-12-oxo-12-H-indolo[2,1-a]isoquinolinium chloride 1 (compound X) and 13-(3,4-dimethoxyphenyl)-2,3,8,9-tetramethoxy-6a, 12a-diazadibenzo[a,g] fluorenylium chloride 2 (compound NF) are new papaverine oxidation products. A solution of compound 1 bleaches on addition of sodium hydroxide solution. A new entity, 2-(2-carboxy-4,5-dimethoxyphenyl)-6,7-dimethoxyisoquinolinium inner salt 3 (compound WP), is formed. The physico-chemical properties of compounds 1-3, such as solubility in water and lipophilicity, have been measured. The IC50 for compounds 1 and 3 was also assessed.

Effect of high intensity exercise on peak oxygen uptake and endothelial function in long-term heart transplant recipients.

Coronary allograft vasculopathy is a well-known long-term complication after cardiac transplantation. Endothelial dysfunction is involved and may be prevented by aerobic exercise. The purpose of this study was to examine whether high intensity aerobic exercise improves peak oxygen uptake (VO(2 peak) ) and endothelial function in heart transplant (HT) recipients. Twenty-seven long-term HT recipients were randomized to either 8-weeks high intensity aerobic exercise or no training. Flow mediated dilation of the brachial artery (FMD) was measured by ultrasound and VO(2 peak) by the analysis of expired air. Blood pressure and biomarkers were measured before and after 8 weeks. VO(2 peak) increased significantly in the exercise group (VO(2 peak) 23.9 ± 1.79 to 28.3 ± 1.63 mL/kg/min compared to controls (VO(2 peak) 24.6 ± 1.38 to 23.4 ± 1.58, p < 0.001 exercise vs. control).FMD increased in the exercise group compared to controls (8.3 ± 1.1% to 11.4 ± 1.2% vs. 5.6 ± 1.0% to 5.3 ± 1.7%, p = 0.024). No increase in nitroglycerin-induced vasodilation was observed. Systolic blood pressure fell in the exercise group (142 ±4.2 mmHg to127 ± 3.4 mmHg, p = 0.01) and was unchanged in controls (141 ± 4.2 mmHg to 142 ±6.4 mmHg, NS). High intensity aerobic exercise reduces systolic blood pressure and improves endothelial function in HT recipients.

Partition coefficients of some purine derivatives and its application to pharmacokinetics.

Metazathioprine (MAZA), a methylated derivative of azathioprine (AZA), demonstrated the greatest values of apparent and specific partition coefficients in n-octanol/phosphate buffer at pH 5.7 and pH 7.4 among purine derivatives such as 6-mercaptopurine (6-MP), 6-thioguanine (6-TG) and AZA. Introduction of a methyl group into the imidazole ring of AZA increases lipophilic properties of MAZA compared to AZA. Mass balance of purine derivatives in n-octanol and in phosphate buffer indicated their chemical stability in those media.

Electron ionisation mass spectral study of 2-(2-carboxy-4, 5-dimethoxyphenyl)-6,7-dimethoxyisoquinolinium inner salt.

The electron ionization mass spectrum of 2-(2-carboxy-4,5-dimethoxyphenyl)-6,7-dimethoxyisoquinolinium inner salt 1 is discussed and general fragmentation routes of its molecular ion are proposed. Comparison of the data obtained for 1 with the EI-MS data of metameric protopine alkaloids (allocryptopine, argemexicaine A, argemexicaine B) and the pseudobenzyloisoquinoline alkaloid taxilamine allows a differentiation between these metamers. The data will be useful for the identification of metabolites of alkaloids of these types in biological matrices.

Effects of acute and chronic attenuation of postprandial hyperglycemia on postglucose-load endothelial function in insulin resistant individuals: is stimulation of first phase insulin secretion beneficial for the endothelial function?

The aim of the study is to determine if attenuation of postprandial hyperglycemia, by acutely and chronically enhancing postprandial insulin secretion in insulin-resistant individuals, improves the endothelial dysfunction. We assessed postoral glucose-load endothelial function in 56 insulin-resistant subjects with the Flow-Mediated-Dilation (FMD) technique. We randomized subjects to intervention/control group, and examined the acute and chronic effect of nateglinide, an oral antidiabetic drug of rapid action. In the intervention group, postoral glucose-load (post-OGL) FMD delta values deteriorated when compared to pre-OGL values, most significantly at 3 h post-OGL, on the following days: on the first study day termed "Baseline day" (p=0.04); on both days after 3 months of nateglinide treatment [with nateglinide administered on study-day "acute+chronic" (p=0.01); and without nateglinide on study-day "Closing day", p=0.001]. Post-OGL changes in the control group were nonsignificant both at Baseline and on Closing day. After a single dose of nateglinide "Acute day", post-OGL FMD deterioration was abolished. There was an increment in post-OGL FMD delta values most significant at 2 h post-OGL (p=0.02). Insulin concentrations increased while glucose concentrations decreased on study-days with nateglinide when compared to study-days without (p=<0.001 for both insulin and glucose). Comparisons for insulin and glucose concentrations between days with nateglinide, and likewise between days without, showed no significant difference. Postglucose load endothelial dysfunction can be prevented by administration of nateglinide, however, after 3 months of nateglinide treatment, this effect is abolished. Chronically increased insulin secretion could counteract the initial beneficial effect of reduced glucose excursions. We found no relationship between postprandial hyperglycemia and post-OGL FMD.

Effects of oral glucose load on endothelial function and on insulin and glucose fluctuations in healthy individuals.

BACKGROUND/AIMS: Postprandial hyperglycemia, an independent risk factor for cardiovascular disease, is accompanied by endothelial dysfunction. We studied the effect of oral glucose load on insulin and glucose fluctuations, and on postprandial endothelial function in healthy individuals in order to better understand and cope with the postprandial state in insulin resistant individuals. METHODS: We assessed post-oral glucose load endothelial function (flow mediated dilation), plasma insulin, and blood glucose in 9 healthy subjects. RESULTS: The largest increases in delta FMD values (fasting FMD value subtracted from postprandial FMD value) occurred at 3 hours after both glucose or placebo load, respectively: 4.80 +/- 1.41 (P = .009) and 2.34 +/- 1.47 (P = .15). Glucose and insulin concentrations achieved maximum peaks at one hour post-glucose load. CONCLUSION: Oral glucose load does not induce endothelial dysfunction in healthy individuals with mean insulin and glucose values of 5.6 mmol/L and 27.2 mmol/L, respectively, 2 hours after glucose load.

Aminoglycoside antibiotics: old drugs and new therapeutic approaches.

Aminoglycoside antibiotics kill bacteria by binding to the ribosomal decoding site and reducing fidelity of protein synthesis. Since the discovery of these natural products over 50 years ago, aminoglycosides have provided a mainstay of antibacterial therapy of serious Gram-negative infections. In recent years, aminoglycosides have become important tools to study molecular recognition of ribonucleic acid (RNA). In an ingenious exploitation of the aminoglycosides' mechanism of action, it has been speculated that drug-induced readthrough of premature stop codons in mutated messenger RNAs might be used to treat patients suffering from certain heritable genetic disorders.

A-site model RNAs.

Oligonucleotide model systems have played a key role for the exploration of structure, dynamics and ligand binding of the ribosomal decoding-site (A site). An overview is given on the merits and limitations of various A-site models that were used for solution and crystallographic work.

Biopharmaceutical characterization of some synthetic purine drugs.

Hydrophilic-lipophilic properties (water solubility, n-octanol/water partition coefficient, transport across membranes) of some mercaptopurines (6-MP, 6-TG, AZA and a new AZA derivative--metazathioprine (MAZA) were determined. MAZA is the most lipophilic compound due to low aqueous solubility and high n-octanol/water partition coefficient. The fluxes from the donor medium into the membrane and from the membrane into the acceptor medium are highest for MAZA as well. The partition coefficients of the other purines decrease in the order: AZA > 6-TG > 6-MP.

Carnitine palmitoyltransferase II deficiency: molecular and biochemical analysis of 32 patients.

The authors investigated 32 patients with the muscle form of CPT II deficiency. Total carnitine palmitoyltransferase enzyme system (CPT) activity was normal but abnormally inhibited by malonyl-CoA, palmitoyl-CoA, and the detergents Triton X and Tween 20. Mutation analysis identified three described mutations (S113L, P50H, and F448L) and two novel mutations (M214T and Y479F). Using modeling techniques, a structure could be identified anchoring the protein in the membrane. Only one of the five mutations (Y479F) is located within this region.

Normal insulin-stimulated endothelial function and impaired insulin-stimulated muscle glucose uptake in young adults with low birth weight.

Low birth weight has been linked to insulin resistance and cardiovascular disease. We hypothesized that insulin sensitivity of both muscle and vascular tissues were impaired in young men with low birth weight. Blood flow was measured by venous occlusion plethysmography during dose-response studies of acetylcholine and sodium nitroprusside in the forearm of fourteen 21-yr-old men with low birth weight and 16 controls of normal birth weight. Glucose uptake was measured during intraarterial insulin infusion. Dose-response studies were repeated during insulin infusion. The maximal blood flow during acetylcholine infusion was 14.1 +/- 2.7 and 14.4 +/- 2.1 [ml x (100 ml forearm)(-1) x min(-1)] in low and normal birth weight subjects, respectively. Insulin coinfusion increased acetylcholine-stimulated flow in both groups: 18.0 +/- 3.1 vs. 17.9 +/- 3.1 [ml x (100 ml forearm)(-1) x min(-1)], NS. Insulin infusion increased glucose uptake significantly in the normal birth weight group, compared with the low birth weight group: 0.40 +/- 0.09 to 1.00 +/- 0.16 vs. 0.44 +/- 0.09 to 0.59 +/- 0.1 [ micro mol glucose x (100 ml forearm)(-1) x min(-1)], P = 0.04. Young men with low birth weight have normal insulin-stimulated endothelial function and impaired insulin-stimulated forearm glucose uptake. Thus, endothelial dysfunction does not necessarily coexist with metabolic alterations in subjects with low birth weight.

Recommendations for the treatment of localized prostate cancer by permanent interstitial brachytherapy.

The increasing use of interstitial brachytherapy for the treatment of prostate cancer has made it necessary to discuss and establish guidelines for the application of this treatment modality. A group of experts representing the four professional and scientific societies of urologic surgeons and radiation oncologists in Germany was formed by the German Society of Urology (Deutsche Gesellschaft für Urologie, DGU), the Association of German Urologists (Berufsverband der Deutschen Urologen e.V., BDU), the German Society for Radiation Oncology (Deutsche Gesellschaft für Radioonkologie, DEGRO) and the Association of German Radiotherapists (Berufsverband der Deutschen Strahlentherapeuten, BVDSt). This group has formulated a consensus statement consisting of recommendations and guidelines for the indications, planning, implementation and follow-up of permanent interstitial brachytherapy by seed implantation for the treatment of localized prostate cancer. These recommendations also define the responsibilities of the two medical disciplines involved in the use of this interdisciplinary treatment.

Mechanism of activation of an immunosuppressive drug: azathioprine. Quantum chemical study on the reaction of azathioprine with cysteine.

Azathioprine is an important drug used in the therapy of autoimmune disorders and in preventing graft rejection. Its molecule is composed of two main moieties: mercaptopurine and imidazole derivative. It is an immunosuppressive agent whose biological activity results from its in vivo mercaptolysis mediated by a nucleophilic attack on the C(5i) atom of imidazole ring of the azathioprine molecule. Solvation model SM5.4 with the PM3 Hamiltonian have been applied to model the reaction of azathioprine with cysteine. The employed quantum mechanical method shed new light on the mechanism of the reaction of azathioprine with cysteine in aqueous solution. The obtained results indicated that the first step in the reaction most likely involves the nucleophilic attack of the COO(-) of cysteine on the C(5i) atom of the imidazole ring of azathioprine, followed by a subsequent intramolecular attack of the SH group of the cysteine residue. It was shown that biogenic thiols such as glutathione or cysteine facilitate the first and crucial step of azathioprine metabolism, due to the presence of COO(-), SH, and NH(3)(+) groups in their molecules.

Proteome analysis of Corynebacterium glutamicum.

By the use of different Corynebacterium glutamicum strains more than 1.4 million tons of amino acids, mainly L-glutamate and L-lysine, are produced per year. A project was started recently to elucidate the complete DNA sequence of this bacterium. In this communication we describe an approach to analyze the C. glutamicum proteome, based on this genetic information, by a combination of two-dimensional (2-D) gel electrophoresis and protein identification via microsequencing or mass spectrometry. We used these techniques to resolve proteins of C. glutamicum with the aim to establish 2-D protein maps as a tool for basic microbiology and for strain improvement. In order to analyze the C. glutamicum proteome, methods were established to fractionate the C. glutamicum proteins according to functional entities, i.e., cytoplasm, membranes, and cell wall. Protein spots of the cytoplasmic and membrane fraction were identified by N-terminal sequencing, immunodetection, matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray ionization-mass spectrometry (ESI-MS). Additionally, a protocol to analyze proteins secreted by C. glutamicum was established. Approximately 40 protein spots were observed on silver-stained 2-D gels, 12 of which were identified.