Use of Isoquercetin in the Treatment of Prurigo Nodularis.

Atopic dermatitis and prurigo nodularis result from complex interactions between the skin, the immune system, and the external environment. The pruritus associated with these conditions greatly impacts patients' quality of life and lacks uniformly effective treatment. A 57-year-old patient presented with severe atopic dermatitis and subsequent prurigo nodularis refractory to numerous standard therapies. The supplement isoquercetin was initiated and he noted significant, sustained reduction in his pruritus after only four weeks. Isoquercetin is a glycoside derivative with antihistamine properties of quercetin, a natural polyphenol flavonoid found in many plants. It may offer itch relief in patients who have failed more conventional therapies.

J Drugs Dermatol. 2017;16(11):1156-1158.

Single- and repeated-dose pharmacokinetics of eplerenone, a selective aldosterone receptor blocker, in rats.

1. The pharmacokinetics of eplerenone (EP) were examined in rats following single or repeated dosing with (14)C-labelled or unlabelled EP to characterize absorption, metabolism and excretion. Rates of EP metabolism and cytochrome P450 activities were determined in vitro after repeated dose administration of EP. 2. Following a single i.v. dose (15 mg kg(-1)), the elimination half-life of EP was 0.80 and 1.14 h in male and female rats, respectively. Plasma clearances (CL) of EP were 1.62 and 1.20 l kg(-1) h(-1) in males and females, respectively. Following a single oral dose (15 mg kg(-1)), C(max) and T(max) of EP were 1.71 micro g ml(-1) and 0.5 h in male rats. The corresponding values in female rats were 3.54 micro g ml(-1) and 1.0 h. The systemic availability of EP was 25.6% in male rats and 66.4% in female rats, demonstrating sex differences in the pharmacokinetics of EP. 3. In the 8-day study, the AUC(0-24h)'s of total EP (closed lactone ring form plus open form) following 100 and 200 mg kg(-1) oral doses were approximately half those on day 1 in male rats. After repeated dosing for 13 weeks, the pharmacokinetics of total EP did not change with study duration at the 20 mg kg(-1) dose in both males and females. However, at the 100 mg kg(-1) dose, AUC(0-24h)'s were notably reduced on day 24 but progressively increased on subsequent days to approximate day 1 levels by day 86 in both sexes. At the 500 mg kg(-1) dose, the AUCs on day 86 remained lower than those on day 1. Reductions in AUCs on days 8 and 24 appeared to be the result of metabolism induction. 4. EP was extensively metabolized in male rats and most faecal and urinary radioactivity was in the form of metabolites. In female rats, the vast majority of urine and faecal radioactivity was associated with total EP. Thus, the sex difference in the pharmakokinetics of EP was due to more extensive metabolism in male rats. 5. The major metabolite in the rat was 6beta-OH EP. EP 6beta-hydroxylase activity was well correlated with testosterone 6beta-hydroxylase activity, indicating that EP metabolism to 6beta-OH EP was mediated primarily by CYP3A in the rat. 6. After repeated dose administration, EP increased 6beta-hydroxylase activities of testosterone and EP itself in a dose-dependent manner in both male and female rats, indicating that EP was a CYP3A inducer in the rat. There appeared to be no effects on activities of CYP1A1, 2B and 2E1.

General and job-related alcohol use and correlates in a municipal workforce.

We examined the prevalence and correlates of both general and workplace-related drinking measures using data from a telephone survey of 673 workers in a large municipal bureaucracy and tested the hypothesis that observed differences across job categories can be explained by compositional difference in terms of demographic variables known to be related to drinking behavior. Results suggest such factors account for much of the variation in general drinking measures (prior-28-day quantity, CAGE score, indicating risk for dependence), but that significant variation in a workplace-related drinking measure (times ever drank before, during, or just after work) remains even after such factors are controlled. Implications of these findings for existing theories of workplace effects on drinking are discussed, along with a consideration of appropriate levels of analysis for future studies.

Purification and characterization of the membrane-bound complex of an ABC transporter, the histidine permease.

The bacterial histidine permease, an ABC transporter, from Salmonella typhimurium is composed of a membrane-bound complex, HisQMP2, comprising two hydrophobic subunits (HisQ and HisM), two copies of an ATP-hydrolyzing subunit, HisP, and a soluble receptor, HisJ. We describe the purification and characterization of HisQMP2 using a 6-histidines extension at the carboxy terminus of HisP [HisQMP2(his6)]. The purification is rapid and effective, giving a seven-fold purification with a yield of 85 and 98% purity. Two procedures are described differing in the detergent used (decanoylsucrose and octylglucoside, respectively) and in the presence of phospholipid. HisQMP2(his6) has ATPase and transport activities upon reconstitution into proteoliposomes (PLS). HisQMP2(his6) has a low level ATPase activity (intrinsic activity), which is stimulated to a different extent by the receptor--liganded and unliganded. Its pH optimum is 7.8-8.0, it requires a cation for activity and it displays cooperativity for ATP. The effect of various ATP analogs was analyzed. Determination of the molecular size of HisQMP2(his6) indicates that it is a monomer. The permeability properties of two kinds of reconstituted PLS preparations are described.

Anthropological perspectives on alcohol and drugs at the turn of the new millennium.

This introduction to the collection provides our thoughts on where alcohol and drug studies in anthropology are going as we enter the new millennium. After commenting briefly on each of the papers that comprise the rest of the volume, we discuss what we see as the most important and exciting issues in the future and give our views on what alcohol and drug studies can offer to medical anthropology, anthropology writ large, interdisciplinary and multidisciplinary research, and the realm of public policy and practical affairs. We call for a continued study by anthropologists of the whole array of pharmacologically active substances used by humans in different parts of the world, whether or not such studies are situated within medical anthropology. We note that many of these substances have received little attention from anthropologists to date, quite strikingly so in the cases of substances such as marijuana and methamphetamines. We emphasize that most scholars working in the anthropology of alcohol and drugs are concerned with the application of their findings to social problems, and we note that this has been especially true of research on alcoholic beverages and injection drugs. This leads us to a discussion of anthropology's involvement in public health intervention and policy work in a variety of settings. Such involvement is shown to have informed anthropological theory (notably political economic approaches) and to have enriched the methodological toolkits and forms of data analysis anthropologists use. Perhaps more importantly, we argue that such multidisciplinary involvement in applied work is most likely to eventuate in theoretical progress in alcohol and drug studies, since theory in the social sciences is not bound to singular disciplinary approaches. Thus we advocate for a "hybrid vigor" in this specialty area in the years ahead.

Nonequivalence of the nucleotide-binding subunits of an ABC transporter, the histidine permease, and conformational changes in the membrane complex.

The membrane-bound complex of the Salmonella typhimurium histidine permease, an ABC transporter (or traffic ATPase), is composed of two membrane proteins, HisQ and HisM, and two identical copies of an ATP-hydrolyzing protein, HisP. We have developed a technique that monitors quantitatively the sulfhydryl modification levels within the intact complex, and we have used it to investigate whether the HisP subunits behave identically within the complex. We show here that they interact differently with various thiol-specific reagents, thus indicating that, despite being identical, they are arranged asymmetrically. The possible basis of this asymmetry is discussed. We have also analyzed the occurrence of conformational changes during various stages of the activity cycle using thiol-specific reagents, fluorescence measurements, and circular dichroism spectroscopy. Cys-51, located close to the ATP-binding pocket, reflects conformational changes upon binding of ATP but does not participate in changes involved in signaling and translocation. The latter are shown to cause secondary structure alterations, as indicated by changes in alpha-helices; tertiary structure alterations also occur, as shown by fluorescence studies.

Social control and workplace drinking norms: a comparison of two organizational cultures.

OBJECTIVE: This article reports on an investigation of the relationship of social control mechanisms at work to drinking practices of 10,000 salaried and hourly employees working in the same U.S. industry, with the same union, but in two different work environments. One work environment reflected an organizational culture that is traditional to U.S. management; the other was based on a nontraditional Japanese transplant model. METHOD: The research team used a combination of methods including in-home surveys (N = 1,723; 1,378 men) and ethnography (110 semistructured interviews and 200 hours of direct observation inside the plants). Respondents were asked about general and work-related drinking, perceptions of drinking norms, strengths or weaknesses of alcohol-related policies and procedures for policy enforcement. RESULTS: Although overall consumption rates in both populations were similar, significant differences between the two samples existed regarding work-related drinking. The Traditional (i.e., U.S.) model was associated with more permissive norms regarding drinking before or during work shifts (including breaks) and higher workplace drinking rates than the Transplant (i.e., Japanese) model. Analyses revealed that alcohol policies, and the extent to which policies are actually enforced, predicted drinking norms and alcohol availability at work. Drinking norms, in turn, predicted work-related drinking and accounted for differences in alcohol consumption between the two worksites. Analyses of ethnographic data provided descriptive understandings of aspects of the two organizational cultures that disabled mechanisms for social control of drinking in one setting and enabled those mechanisms in the other. CONCLUSIONS: These understandings of how social control mechanisms predict work-related drinking practices provide guidelines for alcohol problem prevention in a specific kind of occupational environment. However, our identification of aspects of social control that successfully regulate workplace drinking is applicable to other kinds of occupational settings as well.

Historical and cultural roots of drinking problems among American Indians.

Roots of the epidemic of alcohol-related problems among many Native North Americans are sought in cultural responses to European arrival, the role of alcohol in frontier society, and colonial and postcolonial policies. Evidence from the historical record is considered within the framework of current social science. Initially, Native American's responses to alcohol were heavily influenced by the example of White frontiersmen, who drank immoderately and engaged in otherwise unacceptable behavior while drunk. Whites also deliberately pressed alcohol upon the natives because it was an immensely profitable trade good; in addition, alcohol was used as a tool of "diplomacy" in official dealings between authorities and natives. The authors argue that further research into the origins of modern indigenous people's problems with alcohol would benefit from an interdisciplinary "determinants of health" approach in which biological influences on alcohol problems are investigated in the context of the cultural, social, and economic forces that have shaped individual and group drinking patterns.

Busulfan clearance in renal failure and hemodialysis.

The impact of hemodialysis on the clearance of busulfan was determined in a patient with chronic renal failure undergoing autologous peripheral stem cell transplantation for non-Hodgkin's lymphoma. The extraction ratio for busulfan across the dialyzer was 0.530 +/- 0.026 at a blood flow of 400 ml/min, which corresponds to a hemodialysis clearance of 2.23 +/- 0.11 ml/min/kg body weight. Apparent oral clearance of busulfan without hemodialysis was 3.38 +/- 0.56 ml/min/kg. Thus, a 4 h hemodialysis session enhanced the apparent oral clearance of busulfan by 65%. We conclude that hemodialysis effectively removes busulfan from circulating blood, but a standard hemodialysis period (ie, 4 h) does not significantly alter busulfan exposure. Bone Marrow Transplantation(2000) 25, 201-203.

One intact ATP-binding subunit is sufficient to support ATP hydrolysis and translocation in an ABC transporter, the histidine permease.

The membrane-bound complex of the Salmonella typhimurium histidine permease, a member of the ABC transporters (or traffic ATPases) superfamily, is composed of two integral membrane proteins, HisQ and HisM, and two copies of an ATP-binding subunit, HisP, which hydrolyze ATP, thus supplying the energy for translocation. The three-dimensional structure of HisP has been resolved. Extensive evidence indicates that the HisP subunits form a dimer. We investigated the mechanism of action of such a dimer, both within the complex and in soluble form, by creating heterodimers between the wild type and mutant HisP proteins. The data strongly suggest that within the complex both subunits hydrolyze ATP and that one subunit is activated by the other. In a heterodimer containing one wild type and one hydrolysis defective subunit both hydrolysis and ligand translocation occur at half the rate of the wild type. Soluble HisP also hydrolyzes ATP if one subunit is inactive; its specific activity is identical to that of the wild type, indicating that only one of the subunits in a soluble dimer is involved in hydrolysis. We show that the activating ability varies depending on the nature of the substitution of a well conserved residue, His-211.

Alcohol availability and workplace drinking: mixed method analyses.

OBJECTIVE: This article investigates the relationship between subjective social and physical availability of alcohol at work and work-related drinking. METHOD: We integrated survey and ethnographic methods to determine if and why physical and social availability of alcohol predicted work-related drinking in a manufacturing plant with approximately 6,000 employees. Survey data were obtained from in-home interviews with 984 randomly selected workers. Respondents were asked about their overall and work-related drinking, their perceptions of the ease of obtaining or consuming alcohol in the plant, the work-related drinking of others and their approval/disapproval of work-related drinking by co-workers. Ethnographic data were obtained from 3 years of periodic onsite observations and semistructured interviews with key informants to investigate factors underlying alcohol availability and drinking at work. RESULTS: Structural equations modeling of the survey data revealed that subjective social availability of alcohol at work, and particularly perceived drinking by friends and co-workers, was the strongest predictor of work-related drinking. Typical frequency and quantity of alcohol consumption and heavy drinking were predictive also. Subjective physical availability of alcohol was not significantly related to drinking at or before work. Findings from the ethnographic analyses explained survey findings and described characteristics of the work culture that served to encourage and support alcohol availability and drinking. CONCLUSIONS: These results are the first to show significant relationships between alcohol availability and drinking at work, to explain dynamics of that relationship and to demonstrate the potential risks of using only quantitative or only qualitative findings as the basis for prevention.

Modulation of ATPase activity by physical disengagement of the ATP-binding domains of an ABC transporter, the histidine permease.

The membrane-bound complex of the prokaryotic histidine permease, a periplasmic protein-dependent ABC transporter, is composed of two hydrophobic subunits, HisQ and HisM, and two identical ATP-binding subunits, HisP, and is energized by ATP hydrolysis. The soluble periplasmic binding protein, HisJ, creates a signal that induces ATP hydrolysis by HisP. The crystal structure of HisP has been resolved and shown to have an "L" shape, with one of its arms (arm I) being involved in ATP binding and the other one (arm II) being proposed to interact with the hydrophobic subunits (Hung, L.-W., Wang, I. X., Nikaido, K., Liu, P.-Q., Ames, G. F.-L., and Kim, S.-H. (1998) Nature 396, 703-707). Here we study the basis for the defect of several HisP mutants that have an altered signaling pathway and hydrolyze ATP constitutively. We use biochemical approaches to show that they produce a loosely assembled membrane complex, in which the mutant HisP subunits are disengaged from HisQ and HisM, suggesting that the residues involved are important in the interaction between HisP and the hydrophobic subunits. In addition, the mutant HisPs are shown to have lower affinity for ADP and to display no cooperativity for ATP. All of the residues affected in these HisP mutants are located in arm II of the crystal structure of HisP, thus supporting the proposed function of arm II of HisP as interacting with HisQ and HisM. A revised model involving a cycle of disengagement and reengagement of HisP is proposed as a general mechanism of action for ABC transporters.

Both lobes of the soluble receptor of the periplasmic histidine permease, an ABC transporter (traffic ATPase), interact with the membrane-bound complex. Effect of different ligands and consequences for the mechanism of action.

The histidine permease of Salmonella typhimurium is an ABC transporter (traffic ATPase). The liganded soluble receptor, the histidine-binding protein HisJ, interacts with the membrane-bound complex HisQMP2 and stimulates its ATPase activity, which results in histidine translocation. In this study, we utilized HisJ proteins with mutations in either of the two lobes and wild type HisJ liganded with different substrates to show that each lobe carries an interaction site and that both lobes are involved in inducing (stimulating) the ATPase activity. We suggest that the spatial relationship between the lobes is one of the factors recognized by the membrane-bound complex in dictating the efficiency of the induction signal and of translocation. Several of the key residues involved have been identified. In addition, using constitutive ATPase mutants, we show that the binding protein provides some additional essential function(s) in translocation that is independent of the stimulation of ATP hydrolysis, and one possible mechanism is proposed, which includes the notion that liganded HisJ has different optimal conformations for signaling and for translocation.

In vitro disassembly and reassembly of an ABC transporter, the histidine permease.

The membrane-bound complex of the Salmonella typhimurium periplasmic histidine permease, a member of the ABC transporters (or traffic ATPases) superfamily, is composed of two integral membrane proteins, HisQ and HisM, and two copies of an ATP-binding subunit, HisP. The complex hydrolyzes ATP upon induction of the activity by the liganded soluble receptor, the periplasmic histidine-binding protein, HisJ. Here we take advantage of the modular organization of this system to show that the nucleotide-binding component can be stripped off the integral membrane components, HisQ and HisM. The complex can be reconstituted by using the HisP-depleted membranes containing HisQ and HisM and pure soluble HisP. We show that HisP has high affinity for the HisP-depleted complex, HisQM, and that two HisP molecules are recruited independently of each other for each HisQM unit. The in vitro reassembled complex has entirely normal properties, responding to HisJ and ATPase inhibitors with the same characteristics as the original complex and in contrast to those of soluble HisP. These results show that HisP is absolutely required for ATP hydrolysis, that HisQM cannot hydrolyze ATP, that HisP depends on HisQM to relay the inducing signal from the soluble receptor, HisJ, and that HisQM regulates the ATPase activity of HisP. We also show that HisP changes conformation upon exposure to phospholipids.

Cadmium-induced crystallization of proteins: II. Crystallization of the Salmonella typhimurium histidine-binding protein in complex with L-histidine, L-arginine, or L-lysine.

To further investigate favorable effects of divalent cations on the formation of protein crystals, three complexes of Salmonella typhimurium histidine-binding protein were crystallized with varying concentrations of cadmium salts. For each of the three histidine-binding protein complexes, cadmium cations were found to promote or improve crystallization. The optimal cadmium concentration is ligand specific and falls within a narrow concentration range. In each case, crystals grown in the presence of cadmium diffract to better than 2.0 angstroms resolution and belong to the orthorhombic space group P2(1)2(1)2(1). From our results and from the analysis of cadmium sites in well-refined protein structures, we propose that cadmium addition provides a generally useful technique to modify crystal morphology and to improve diffraction quality.

Crystal structure of the ATP-binding subunit of an ABC transporter.

ABC transporters (also known as traffic ATPases) form a large family of proteins responsible for the translocation of a variety of compounds across membranes of both prokaryotes and eukaryotes. The recently completed Escherichia coli genome sequence revealed that the largest family of paralogous E. coli proteins is composed of ABC transporters. Many eukaryotic proteins of medical significance belong to this family, such as the cystic fibrosis transmembrane conductance regulator (CFTR), the P-glycoprotein (or multidrug-resistance protein) and the heterodimeric transporter associated with antigen processing (Tap1-Tap2). Here we report the crystal structure at 1.5 A resolution of HisP, the ATP-binding subunit of the histidine permease, which is an ABC transporter from Salmonella typhimurium. We correlate the details of this structure with the biochemical, genetic and biophysical properties of the wild-type and several mutant HisP proteins. The structure provides a basis for understanding properties of ABC transporters and of defective CFTR proteins.

Predicting likelihood of seeking help through the employee assistance program among salaried and union hourly employees.

AIMS: This research investigated belief, social support and background predictors of employee likelihood to use an Employee Assistance Program (EAP) for a drinking problem. DESIGN: An anonymous cross-sectional survey was administered in the home. Bivariate analyses and simultaneous equations path analysis were used to explore a model of EAP use. SETTING: Survey and ethnographic research were conducted in a unionized heavy machinery manufacturing plant in the central states of the United States. PARTICIPANTS: A random sample of 852 hourly and salaried employees was selected. MEASUREMENTS: In addition to background variables, measures included: likelihood of going to an EAP for a drinking problem, belief the EAP can help, social support for the EAP from co-workers/others, belief that EAP use will harm employment, and supervisor encourages the EAP for potential drinking problems. FINDINGS: Belief in EAP efficacy directly increased the likelihood of going to an EAP. Greater perceived social support and supervisor encouragement increased the likelihood of going to an EAP both directly and indirectly through perceived EAP efficacy. Black and union hourly employees were more likely to say they would use an EAP. Males and those who reported drinking during working hours were less likely to say they would use an EAP for a drinking problem. CONCLUSIONS: EAP beliefs and social support have significant effects on likelihood to go to an EAP for a drinking problem. EAPs may wish to focus their efforts on creating an environment where there is social support from coworkers and encouragement from supervisors for using EAP services. Union networks and team members have an important role to play in addition to conventional supervisor intervention.

Purification and characterization of HisP, the ATP-binding subunit of a traffic ATPase (ABC transporter), the histidine permease of Salmonella typhimurium. Solubility, dimerization, and ATPase activity.

The nucleotide-binding subunit, HisP, of the histidine permease, a traffic ATPase (ABC transporter), has been purified as a soluble protein and characterized. Addition of a 6-histidine extension (HisP(His6)) allows a rapid and effective metal affinity purification, giving a 30-fold purification with a yield of 50%. HisP(his6) is indistinguishable from underivatized HisP when incorporated into the permease membrane-bound complex, HisQMP2. Purified HisP(his6) has a strong tendency to precipitate; 5 mM ATP and 20% glycerol maintain it in solution at a high protein concentration. HisP(his6) is active as a dimer, binds ATP with a Kd value of 205 microM, and hydrolyzes it at a rate comparable to that of HisQMP2; in contrast to the latter, it does not display cooperativity for ATP. HisP(his6) has been characterized with respect to substrate and inhibitor specificity and various physico-chemical characteristics. Its pH optimum is 7 and it requires a cation for activity, with Co2+ and Mn2+ being more effective than Mg2+ at lower concentrations but inhibitory in the higher concentration range. In contrast to the intact complex, HisP(his6) is not inhibited by vanadate but is inhibited by N-ethylmaleimide. Neither the soluble receptor, HisJ, nor the transport substrate, histidine, has any effect on the activity.

Characterization of the adenosine triphosphatase activity of the periplasmic histidine permease, a traffic ATPase (ABC transporter).

The superfamily of traffic ATPases (ABC transporters) includes bacterial periplasmic transport systems (permeases) and eukaryotic transporters. The histidine permease of Salmonella typhimurium is composed of a membrane-bound complex (HisQMP2) containing four subunits, and of a soluble receptor, the histidine-binding protein (HisJ). Transport is energized by ATP. In this article the ATPase activity of HisQMP2 has been characterized, using a novel assay that is independent of transport. The assay uses Mg2+ ions to permeabilize membrane vesicles or proteoliposomes, thus allowing access of ATP to both sides of the bilayer. HisQMP2 displays a low level of intrinsic ATPase activity in the absence of HisJ; unliganded HisJ stimulates the activity and liganded HisJ stimulates to an even higher level. All three levels of activity display positive cooperativity for ATP with a Hill coefficient of 2 and a K0. 5 value of 0.6 mM. The activity has been characterized with respect to pH, salt, phospholipids, substrate, and inhibitor specificity. Free histidine has no effect. The activity is inhibited by orthovanadate, but not by N-ethylmaleimide, bafilomycin A1, or ouabain. Several nucleotide analogs, ADP, 5'-adenylyl-beta, gamma-imidodiphosphate, adenosine 5'-(beta,gammaimino)triphosphate, and adenosine 5'-O-(3-thio)triphosphate, inhibit the activity. Unliganded HisJ does not compete with liganded HisJ for the stimulation of the ATPase activity of HisQMP2.