Synthetic Pyridoindole and Rutin Affect Upregulation of Endothelial Nitric Oxide Synthase and Heart Function in Rats Fed a High-Fat-Fructose Diet.

Metabolic syndrome (MetS) belongs to the serious health complications expanding in cardiovascular diseases, obesity, insulin resistance, and hyperglycemia. In this study, hypertriacylglycerolemic rats fed a high-fat-fructose diet (HFFD) were used as an experimental model of MetS to explore the effect of tested compounds. Effects of a new prospective pyridoindole derivative coded SMe1EC2 and the natural polyphenol rutin were tested. Endothelial nitric oxide synthase (NOS3) and nuclear factor kappa B (NF-?B) expression were assessed in the left ventricle immunohistochemically and left ventricle activity was monitored in isolated perfused rat hearts. NOS3 activity in the left ventricle decreased markedly as a result of a HFFD. NOS3 expression was upregulated by both substances. NF-?B expression was increased in the MetS group in comparison to control rats and the expression further increased in the SMe1EC2 treatment. This compound significantly improved the coronary flow in comparison to the control group during reperfusion of the heart followed after ischemia. Further, it tended to increase left ventricular systolic pressure, heart product, rate of maximal contraction and relaxation, and coronary flow during baseline assessment. Moreover, the compound SMe1EC2 decreased the sensitivity of hearts to electrically induced ventricular fibrillation. Contrary to this rutin decreased coronary flow in reperfusion. Present results suggest that despite upregulation of NOS3 by both substances tested, pyridoindole SMe1EC2 rather than rutin could be suitable in treatment strategies of cardiovascular disorders in MetS-like conditions.

Neglected infections of poverty in Texas and the rest of the United States: management and treatment options.

In the poorest regions of the United States, especially along the Gulf Coast and in South Texas, are a group of endemic parasitic and related infections known as the neglected infections of poverty. Such infections are characterized by their chronicity, disabling features, and disproportionate impact on the estimated 46 million people who live below the U.S. poverty line. Today more Americans live in poverty than ever before in the half-century that the Census Bureau has been recording poverty rates. In association with that poverty, a group of major neglected infections of poverty have emerged in the United States. Here we describe the major neglected infections of poverty in the United States, with a brief overview of their significant epidemiological features, their links with poverty, and our approaches to their diagnosis, management, and treatment.

Controversy of free radical hypothesis: reactive oxygen species--cause or consequence of tissue injury?

For a decade or two, the hypothesis of causality of various disorders by reactive oxygen species (ROS), due to their potentially harmful effect towards cellular constituents, is one of the most frequently cited in biomedical sciences. In fact, the ROS-mediated alterations of biomacromolecules are considered to be essential events in the etiopathogenesis of those diseases where involvement of ROS has been indicated. ROS easily react in vitro with most biological molecules, causing their degradation and destruction. This may implicitly suggest that, when excessively produced in vivo, ROS are deleterious to integral components of the cell and cause their dysfunctions. Some experimental data indicate that ROS-mediated lipid peroxidation, protein oxidation and oxidative alterations to nucleic acids are crucial events of unfavorable actions of ROS. Yet the most convincing evidence, i.e. unambiguous inhibition of tissue injury by pretreatment with antioxidants, has not been provided. On the contrary, there are quite a few papers reporting failure in applying antioxidants to heal those pathologies where the causal role of ROS was supposed. Other papers reported serious complications arising from antioxidant therapy, which is quite in contradiction to its expected effect. On the other hand, an increasing number of recent findings have provided evidence of a key role of ROS in both intracellular signaling and intercellular communication, processes involved in maintaining homeostasis. Hence, some investigators consider excessive production of ROS to be rather a "smoke after the fire" than "a deleterious fire" itself, suggesting the occurrence of overproduced ROS as being the consequence of some primary damage. The present paper aims at summarizing some pros and cons of various opinions with an attempt to help better understand the involvement of ROS in tissue injury.

Extraction and chromatographic separation methods in pharmacokinetic studies of Stobadine--an indole-related antioxidant and free-radical scavenger.

This overview provides comprehensive information on the most relevant results of Stobadine preclinical disposition studies. In order to investigate pharmacokinetic processes of the drug in rats, dogs and in human volunteers, several bioanalytical assays based on radiometric, spectrofluorometric, as well as chromatographic determination methods were developed and implemented. In small laboratory animals, the drug absorption, distribution, metabolism and elimination were investigated by administering 3H-labeled Stobadine. Spectrofluorometry was used alternatively for the determination of cold/unlabeled Stobadine in extracts of biomaterials sampled from larger animal species. The chromatographic separation methods proved, however, to be the most advantageous for determining details of the drug disposition and fate in the body.

Bioavailability and pharmacokinetic studies in the development of an oral formulation of stobadine dipalmitate.

The pyridoindole stobadine is a novel drug with antioxidant and cardioprotective properties. The objective of this study was to compare the bioavailability and the main pharmacokinetic parameters of two different stobadine dosage forms, STBtest and STBref, after single oral dosing in the form of gelatine capsules to 6 dogs. The dose ranged from 2.9 to 4.7 mg/kg and a randomized two-period crossover design was applied. To quantify the drug in plasma, a GC/MS method was developed with a quantification limit of 1 ng/ml. The time profiles of stobadine plasma concentrations were fitted by pharmacokinetic models. The extent of relative bioavailability ranged between 0.71 and 1.56. Practically no difference was found between the bioavailability rate of the two capsules, expressed as Cmax/AUC, with values ranging from 0.0022-0.0047 min-1 for STBtest and 0.0022-0.0045 min-1 for STBref. In conclusion, the technological difference of the capsules investigated did not yield deviations in either their extent or rate of absorption. Therefore the two stobadine formulations were concluded to be bioequivalent.

Pharmacokinetic study of stobadine.

The aim of this paper is to provide a brief overview of most important results of stobadine kinetic studies in rats, dogs, and human volunteers. In these studies, stobadine dihydrochloride and stobadine dipalmitate was used for intravenous and oral administration, respectively. To evaluate kinetic properties of stobadine and its metabolites, TLC, HPLC, GLC, GC-MS, radiometric, and fluorometric methods were developed and used.

An asthma management program for urban minority children.

Morbidity and mortality continue to increase for children with asthma. Minority children have disproportionately higher rates of adverse outcomes on almost all disease measures. An asthma management program for urban minority children was developed with research-based intervention strategies and insights gained from the child and family perspectives on illness and health care delivery. The goal of the intervention program was to deliver care that was culturally sensitive, focused on decreasing barriers to appropriate self-management, and committed to promoting partnerships among children, families, the health care system, and the broader community.

Breastfeeding promotion for the employed mother.

Increasing numbers of mothers are returning to work during the first year of their infant's life. Maternal employment has been associated with decreased duration of breastfeeding. Breast milk remains the optimal source of infant nutrition, yet only 50% of families choose breastfeeding for their newborns. Clinicians in pediatrics are well positioned to promote the specific benefits to mother and baby that breastfeeding provides through advocacy, education, and support with regard to breastfeeding and employment. Anticipatory guidance specifics such as feeding patterns, guidelines for pumping and storing breast milk, and information regarding available resources are clinical knowledge areas that pediatric health care providers must have to increase breastfeeding rates and duration among women who return to the work force after the birth of their baby.

The effect of cytochromes P4501A induction and inhibition on the disposition of the cognition activator tacrine in rat hepatic preparations.

1. The disposition of tacrine 1,2,3,4-tetrahydro-9-acridinamine monohydrochloride monohydrate (THA, Cognex), was studied using livers obtained from control, phenobarbital (PB), isosafrole (ISO), and 3-methycholanthrene (3-MC) treated rats. 2. Pretreatment of rats with PB, ISO, and 3-MC reduced AUC(10-120 min) of THA in liver perfusates by 28, 32, and 86% respectively. 3. Elimination of [14C]-THA-derived radioactivity into bile was 7.6 +/- 1.2%, 11.7 +/- 2.9%, 14.8 +/- 2.0%, and 46.3 +/- 9.7% (mean +/- SD) of the infusion dose for control PB, ISO, and 3-MC pretreated isolated perfused rat livers, respectively. 4. In perfusion experiments using 3-MC pretreated livers, a marked increase in irreversible protein binding of 3-, 7-, and 8-fold was observed to microsomal, cytosolic and total liver proteins, respectively, compared to control. Only a slight effect was observed on protein binding in perfusion experiments using PB and ISO pretreated animals. 5. Co-incubations of [14C]-THA with the metabolic inhibitors enoxacin, ethimizol, and furafylline in hepatocyte preparations obtained from 3-MC pretreated rats markedly inhibited THA-derived irreversible protein binding. Furafylline, a specific inhibitor of cytochrome P4501A2, had the greatest inhibitory effect (approximately 70%). 6. These results are consistent with a major role of cytochrome P4501A in the metabolism and irreversible protein binding of THA in rat liver and demonstrate the utility of isolated liver perfusion and hepatocyte models for examining the effect of metabolic modulators.

Selective uptake of the anticancer drug bendamustine by liver and kidney tissues following its intravenous administration to mice.

Distribution of 14C-bendamustine following intravenous (i.v.) administration to mice was examined by whole body autoradiographic (WBAR) and quantitative techniques. The WBAR study showed that 14C-bendamustine-derived radioactivity was distributed extremely unevenly at each time interval investigated. After 5 min of administration the highest density of radioactive material was found in the liver and in the kidney. At all time intervals investigated the brain remained free of the label. In a detailed quantitative distribution study it was found that 14C-bendamustine-derived radioactivity was also unevenly distributed throughout the mouse tissues. At 5 min postdosing the level of 14C was by one order higher in the liver and in the kidney in comparison to the lungs, heart, spleen, and muscle. The results of both WBAR and quantitative tissue distribution studies suggest that bendamustine was selectively taken up from the blood by liver and kidney tissues. Because of this pharmacokinetic property, dose modification should be taken into consideration when administering the drug to patients suffering from hepatobiliary and kidney disorders.

Role of hepatovasculature in warm ischaemia-reperfusion injury of rat liver.

Liver haemodynamics were studied after warm (37 degrees C) ischaemia of isolated rat livers for periods of 30 s (Group 1), 30 min (Group 2), and 60 min (Group 3) using a constant pressure system with a recirculating blood-free perfusate. Portal flow recovered to basal values within 6 min in livers from Group 1, whereas it was significantly reduced in Group 2 during the initial 15 min and in Group 3 during the first 33 min of reperfusion. Thus, the recovery of liver flow was proportional to the duration of ischaemia. By using the same mode of liver perfusion, the effect of norepinephrine on portal resistance was also studied in normal livers. At the beginning of reperfusion, the values of portal resistance in ischaemic livers were comparable to the values of portal resistance mediated by norepinephrine at concentrations between 10(-7) and 10(-6) mol/l in normal livers. The results suggest that vasoconstriction of the hepatovasculature may be a contributing factor to the reperfusion injury of the liver following warm ischaemia.

Uptake, reflux, and excretion of bromosulfophthalein in ischaemia-reperfusion injury of rat liver.

The uptake, reflux and excretion of bromosulfophthalein (BSP) were studied on a model of total warm ischaemia for 30 min (group 1) or 60 min (group 2) followed by reperfusion for 45 min in the isolated perfused rat liver of unfasting rats. In group 1, the BSP hepatic uptake was comparable to control livers (30 s ischaemia plus 45 min reperfusion), but was significantly reduced in group 2. The reflux of BSP from liver to perfusate in group 1 and group 2 resulted in the appearance of secondary concentration time peaks of BSP in the reservoir perfusate. This result suggests that ischaemia-reperfusion induced a qualitative change in BSP pharmacokinetics. Excretion of the dye into bile was significantly impaired in group 2 only. The leakage of lactate dehydrogenase into the perfusate was increased moderately in both group 1 and group 2 in comparison to the controls, suggesting a low degree of liver parenchymal injury. In conclusion, the results of this investigation showed that BSP pharmacokinetics were not only undergoing quantitative changes but also a qualitative change in the model of ischaemia-reperfusion injury of the liver obtained from fed rats and may thus serve as a highly sensitive indicator of liver viability.

Metabolic disposition of tacrine in primary suspensions of rat hepatocyte and in single-pass perfused liver: in vitro/in vivo comparisons.

1. Incubations of tacrine (1,2,3,4-tetrahydro-9-acridinamine monohydrochloride monohydrate, THA) with a primary suspension of rat hepatocytes for 2 min resulted in formation of the 1-hydroxy derivative as the major metabolite with smaller amounts of the 2- and 4-hydroxy metabolites. 2. Apparent Vmax and Km for THA metabolism were 12.4 +/- 3.3 nmol/min/g liver and 0.98 +/- 0.34 microM respectively. 3. Incubations of THA for longer time-periods (> 10 min) resulted in irreversible binding of THA-derived radioactivity to hepatocellular protein. The apparent maximal rate of irreversible binding (Bmax) was 76.7 +/- 30.5 pmol equivalents bound/h/mg cell protein, whereas the apparent Kb for binding was 2.8 +/- 1.4 microM. 4. The kinetic parameters, Vmax and Km, were used to predict steady-state extraction ratios (ERSS) for various THA input concentrations (Cin) in single-pass perfused rat liver. At low input concentrations (0.72-0.85 microM; Cin < Km), ERSS of THA was approximately 1. For higher Cin (14.05, 20.72, 20.88 microM; Cin >> Km), the calculated ERSS was markedly decreased with 0.300, 0.296 and 0.261, respectively. 5. The intrinsic clearance of THA (Cli) estimated from in vitro hepatocyte data was 6.7 ml/min/g liver while the apparent oral THA clearance (Cloral) calculated from in vivo rat data was 6.6 ml/min/g liver.

Hepatobiliary disposition of 3'-azido-3'-deoxythymidine (AZT) in the rat: effect of phenobarbitone induction.

Isolated liver with a recirculating perfusate was used to study 3'-azido-3'-deoxythymidine (AZT) disposition in phenobarbitone-pretreated rats at 68 microM AZT concentration in the reservoir. Clearance of AZT in the livers obtained from control animals was 0.42 +/- 0.01 (mean +/- s.d.) mL min-1/10 g liver. Over the study period of 105 min, 12.7 +/- 2.6% of the dose was excreted in bile and of this 95% was recovered as 3'-azido-3'-deoxy-5'-O-beta-D-glucopyranuronosylthymidine (GAZT). The amount of GAZT found in the perfusate after 105 min of liver perfusion was < 1% of the AZT dose introduced into the reservoir. Phenobarbitone pretreatment of rats resulted in a 5.5-fold increase of AZT clearance. In addition, the area under the perfusate concentration-time curve (AUC0-105 min) for 3'-amino-3'-deoxythymidine (AMT) and for a catabolite of unknown structure was increased 3- and 10-fold, respectively, and the amount of AZT dose excreted in the bile was nearly doubled. Thus phenobarbitone was capable of stimulating both detoxification of AZT to GAZT and bioactivation of AZT to AMT, a catabolite known to be highly toxic to human bone marrow cells. This induction was the result of enhancement of AZT catabolism rather than its transport into the cells, since on incubation of AZT (0-250 microM) with rat isolated hepatocytes, a linear relationship between concentration and amount taken up by the cells was shown. In addition, the rate of AZT uptake was not influenced by KCN, dinitrophenol, or temperature, which is consistent with a simple diffusion of AZT through the hepatocellular membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

On the absorption of drugs using chronic dog ileal loop method.

The absorption rate of three model drugs, i.e., pentacaine (highly lipophilic), stobadine (moderately lipophilic) and acetylsalicylic acid (hydrophilic), was studied using the chronic dog ileal loop method. The drugs were dissolved either in 0.9% unbuffered solution of NaCl or in antacid mixture. When using 0.9% NaCl, the half-lives of absorption (t1/2 (dis)) of pentacaine and stobadine were (mean +/- SD) 23.2 +/- 7.8 min and 20.8 +/- 7.2 min, respectively. For stobadine a good agreement was found between its t1/2 (dis) from the ileum and its absorption half-life determined from blood concentrations after oral administration to dogs. The absorption of acetylsalicylic acid accounted for only 10-20% of the dose introduced into the loop over 45 min; thus, a reliable value of t1/2 (dis) could not be determined. The administration of unbuffered solution of NaCl into the loop was accompanied by rapid increase of pH from acidic to basic value. The antacid mixture failed to affect the absorption rate of the drugs studied. Sampling from the ileum was limited to 35-55 min due to rapid absorption of water. These results suggest that: 1) measurement of the absorption rate of some drugs, e.g., stobadine, by using the chronic dog ileal loop method may adequately predict their absorption rate after peroral administration to the dog, 2) interactions of antacids with drug absorption in the ileum may not play a significant role because of the strong buffering capacity of the ileum, and 3) rapid absorption of water from the ileum does not allow to reliably determine the value of t1/2 (dis) for slowly absorbed drugs.

Hepatobiliary elimination of bendamustin (Cytostasan) in rats.

Biliary excretion of bendamustin (Cytostasan, 5-[bis(2-chloroethyl)amino]-i-methylbenzimidazole-2-butyric acid; 1) and its metabolites was studied in rats after i.v. administration of 14C-1. The most significant finding was the rapid excretion of 1 related radioactivity in the bile occurring shortly after injection. While radioactivity eliminated by bile within 2 h was 41.8%, in the course of subsequent 22 h it amounted only to 3.2%. Bile samples analyzed by TLC indicated that the total amount of radioactivity was excreted in the form of conjugates and two hydroxy metabolites. A significant amount of radioactivity was excreted in urine. The diversion of bile by cannulation of the bile duct led to a significant decrease of elimination by feces.

The effect of high energy electron irradiation on blood-brain barrier permeability to haloperidol and stobadin in rats.

The heads of rats were irradiated by 4 MeV electrons in doses 90, 180, and 360 Gy. The observed times of deaths ranged 120-600, 60-420, and 150-370 min after 90, 180, and 360 Gy, respectively. A dose dependent decrease of the brain uptake index of haloperidol was observed 1 and 3 h post radiation. On the other hand an increased brain uptake index was found for stobadin after head irradiation with doses of 180 and 360 Gy. Regional cerebral blood flow, blood pressure, and heart rate were not significantly altered in the period following irradiation with 180 Gy. The observed changes in blood-brain barrier (BBB) permeability seem to be the result of the damaged function of morphological structures forming the BBB rather than altered regional blood flow.

A high-performance liquid chromatographic method for the determination of stobadin pharmacokinetics in serum.

A high-performance liquid chromatographic method was developed to determine stobadin pharmacokinetics in dog and man. The relative bioavailability of stobadin dipalmitate compared with dihydrochloride was 46.4 per cent in dog. In man peak serum concentrations ranged from 12 to 289 ng ml-1 after a single oral dose of stobadin dipalmitate (0.79 to 2.5 mgkg-1).