The renal excretory mechanisms and the role of organic cations in modulating the renal handling of paraquat

Paraquat (PQ), a cationic herbicide, is predominantly excreted by the kidneys, but it is also nephrotoxic. It is thought to cause damage to proximal renal epithelial cells, which results in acute renal failure. The precise mechanism by which PQ is excreted by the kidney has not been fully elucidated, although current evidence indicates that it is actively secreted via a cation transport system. This review examines the renal cytotoxic effect and excretory mechanisms of PQ, and the role of organic cations in modulating the renal handling of PQ.

Smooth muscle dysfunction occurs independently of impaired endothelium-dependent dilation in adults at risk of atherosclerosis

OBJECTIVES

We sought to assess smooth muscle function in adults at risk for atherosclerosis.

BACKGROUND

Previous studies in subjects at risk for atherosclerosis have demonstrated arterial endothelial dysfunction, with reduced vasodilator responses after pharmacologic or physiologic stimulation of endothelial nitric oxide (NO). Most have also shown a slight but nonsignificant impairment of vasodilation in response to exogenous sources of NO, such as nitroglycerin (NTG). We hypothesized that NTG responses might be reduced in a large number of consecutively studied adults at risk for atherosclerosis, independent of any impaired endothelium-dependent responses, consistent with concomitant smooth muscle dysfunction.

METHODS

Using high resolution ultrasound, the dilator response of the brachial artery to 400 microg of sublingual NTG was measured in 800 asymptomatic subjects. Subjects were also assessed for a history of vascular risk factors, blood pressure, total serum cholesterol and flow-mediated endothelium-dependent dilation (EDD).

RESULTS

We studied 317 men and 483 women, 38 +/- 17 years old (mean +/- SD, range 15 to 76). The mean cholesterol level was 5.2 +/- 1.3 mmol/liter, and there were 126 smokers and ex-smokers (16 +/- 9 mean pack-years) and 105 diabetic subjects. On univariate analysis, a reduced vasodilator response to NTG was associated with high cholesterol, cigarette smoking, diabetes mellitus, increasing age, male gender, larger vessel size and reduced EDD (p < or = 0.01 for all). On multivariate analysis, diabetes, larger vessel size and reduced EDD were all independently associated with impaired NTG-related vasodilation (p < or = 0.001 for all). In the 574 nondiabetic subjects who had never smoked cigarettes, the independent relation between EDD and NTG responses was still observed (r = 0.24, p = 0.01).

CONCLUSIONS

The vasodilator response to exogenous NO is impaired in asymptomatic subjects with reduced EDD, consistent with smooth muscle dysfunction in adults at risk for atherosclerosis.

Effect of changing the fine particle mass of inhaled beclomethasone dipropionate on intrapulmonary deposition and pharmacokinetics

Reformulation of beclomethasone dipropionate (BDP) in the chlorofluorocarbon (CFC)-free propellant hydrofluoroalkane-134a (HFA) gave the opportunity to produce a solution formulation that provides a greater total mass of fine drug particles than the current CFC suspension metered dose inhaler (MDI). The HFA-BDP MDI was studied in three pharmacokinetic trials in asthmatic patients. Serum levels of BDP plus metabolites [total beclomethasone (total BOH) assay] were used to test whether the increased fine particle mass of HFA-BDP would result in improved intrapulmonary deposition and subsequent differences in serum profiles. Serum levels, maximum serum concentrations and area under the serum concentration-time curves of total BOH following both single and multiple doses of HFA-BDP were similar to those obtained with approximately twice the dose of CFC-BDP. The observed lower bioavailability of CFC-BDP compared with HFA-BDP could be explained if most of each inhaled dose from the CFC-BDP MDI was swallowed and absorbed from the gastrointestinal tract, while most of each inhaled dose from the HFA-BDP MDI was absorbed from the lungs. Deposition studies have confirmed this explanation. These results suggest that asthmatic patients can be treated with lower total daily doses of drug from HFA-BDP extrafine aerosol than from CFC-BDP.

Degradation products of beclomethasone dipropionate in human plasma

The anti-inflammatory glucocorticosteroid beclomethasone dipropionate was found previously to degrade in human plasma at 37 degrees C to yield beclomethasone 17-monopropionate, beclomethasone 21-monopropionate, and beclomethasone together with three unknown species, D-1, D-2, and D-3. In this paper, we report the isolation of D-2 and D-3 by preparative HPLC and the elucidation of their structures. Both products D-2 and D-3 exhibited UV bathochromic shifts relative to beclomethasone dipropionate of 9 nm. From the mass spectrometry and 1H-NMR data, it is concluded that D-2 and D-3 are formed from beclomethasone and beclomethasone 21-monopropionate, respectively, with the loss of hydrogen chloride and the formation of a 9,11-epoxide. Data for 1H-NMR methyl chemical shifts are used to show that the epoxide has the mechanistically more plausible 9beta,11beta configuration. Thus, D-2 is 9beta, 11beta-epoxy-16beta-methyl-1,4-pregnadiene-17alpha,21- diol-3, 20-dione, and D-3 is its corresponding 21-propanoate. The various enzyme-catalyzed and nonenzyme-catalyzed reactions involved in the degradation of beclomethasone dipropionate in human plasma are discussed. A degradation scheme is proposed.

Decomposition of beclomethasone propionate esters in human plasma

The kinetics of decomposition of beclomethasone dipropionate (BDP), the 17-monopropionate ester (17-BMP), and beclomethasone (BOH) were characterized in whole human plasma (HP), pH 7.1, and in solutions of 1% human serum albumin (HSA), pH 7.4, and 0.067 M phosphate buffer, pH 7.4 (mu = 0.17). A reversed-phase, high-performance liquid chromatography (HPLC) assay enabled simultaneous separation and quantification of beclomethasone propionate esters and six degradation products including three unidentified products, D1-D3, not previously reported. Following incubation of BDP, products were formed in the following sequence, D1, 17-BMP, beclomethasone-21-monopropionate (21-BMP), D3, BOH, and D2. Following incubation of 17-BMP, the same sequence of degradation products was formed with the exception of D1. Following incubation of BOH, only D2 was formed. The decomposition reactions of BDP, 17-BMP, and BOH in HP exhibit pseudo-first-order kinetics. However the degradation reactions of BDP in solutions of 1% HSA and phosphate buffer were found to follow pseudo-zero-order kinetics. At an initial concentration of 40 micrograms mL-1, the half-lives for BDP, 17-BMP, and BOH in HP were 10.9 +/- 0.4, 3.0 +/- 0.2 and 24.8 +/- 0.2 h, respectively.

Effects of budesonide and fluticasone on 24-hour plasma cortisol. A dose-response study

Comparison of the risk-benefit profiles of different inhaled glucocorticoids has been limited by inadequate information about the dose-response relationships for efficacy relative to side effects. Fluticasone propionate (FP) is twice as effective as budesonide (BUD), but the potency ratio of FP:BUD with respect to suppression of cortisol production is unknown. The effects of 5 d of treatment with BUD (800, 1,600, and 3,200 micrograms/d via pMDI) and FP (750, 1,500, and 2,000 micrograms/d via pMDI) on integrated area under the curve of 24-h plasma cortisol profiles (AUC24 h) were compared in a randomized, placebo-controlled, seven-period crossover study in normal male volunteers (n = 28). Plasma cortisol concentrations were measured during the last 24 h of each treatment period. Each treatment (except BUD 800 micrograms) produced significant dose-dependent reductions in AUC24 h compared with placebo; e.g., percent reductions in AUC24 h were 23, 41, and 69% for the three doses of BUD, and, correspondingly, 46, 85, and 93% for the three doses of FP. Model-derived measurements of dose potency ratios showed that FP was 2.9 times more potent than BUD in reducing AUC24 h (95% CI, 2.5 to 3.5) and 3.1 times more potent in reducing 8:00 A.M. plasma cortisol (95% CI, 2.4 to 4.0). Thus, on a microgram-for-microgram notional dose basis, the systemic effects of a given dose of FP on AUC24 h cortisol were equivalent to the effects of three times the dose of BUD.

An evaluation of two primary care interventions for alcohol abuse among Mexican-American patients

AIMS

This study examined the effects of two primary care interventions (a physician intervention and a clinic-based psychoeducational group) on drinking patterns, psychosocial problems and blood test results (MCV, GGT, SGOT and SGPT).

DESIGN

Subjects were randomized into one of four treatment groups: physician intervention, psychoeducation, both interventions, or no intervention. Follow-up data were collected at 12 and 18 months.

SETTING

Subjects were recruited from a family practice outpatient clinic managed by a public hospital.

PARTICIPANTS

Included 175 Mexican-American female and male primary care patients who screened positive for alcohol abuse or dependence. These patients were not seeking help for alcohol problems.

INTERVENTIONS

Included a brief physician intervention and a 6-week patient psychoeducational group.

MEASUREMENTS

The Diagnostic Interview Schedule assessed subjects for alcohol abuse; the Addiction Severity Index measured alcohol-related problems, including psychosocial issues.

FINDINGS

All four treatment groups demonstrated significant improvement over time, with few differences between intervention and control groups.

CONCLUSIONS

Assessment can be confounded with brief interventions; future investigators should use non-assessed control groups.

Transport of paraquat by a renal epithelial cell line, MDCK

Transport of paraquat (PQ), a herbicidal cation, was previously investigated in a proximal (LLC-PK1), renal epithelial cell line using permeable collagen-coated filters. PQ was actively transported from the basolateral side via a cation transport system by the LLC-PK1 cells. In the present study, the transport of PQ was investigated in a distal renal epithelial cell line, MDCK. PQ was predominantly transported from the basolateral to apical (B to A) side. The basolateral transport of PQ in MDCK cells was not saturable with increasing concentrations and not energy dependent. The flux and uptake of PQ was much lower in the MDCK than LLC-PK1 cells. It is concluded that MDCK, a distal renal tubular cell line, does not have an active transport system for PQ.

A sensitive method for the quantification of fluticasone propionate in human plasma by high-performance liquid chromatography/atmospheric pressure chemical ionisation mass spectrometry

A highly sensitive and selective method has been developed for the quantification of fluticasone propionate (FP) in human plasma. The drug was isolated from human plasma using C18 solid-phase extraction cartridges. The analysis was based on high-performance liquid chromatography/atmospheric pressure chemical ionisation mass spectrometry (HPLC/APCI/MS), using the 22R epimer of budesonide (BUD) acetate, synthesised using acetic anhydride, as internal standard. The mass spectrometer was operated in APCI mode with selected ions at tune masses of 473.2 and 501.2 m/z, corresponding to the MH+ of acetylated (22R)BUD and FP, respectively. The mobile phase used was a mixture of 50% ethanol in water with a flow rate of 0.45 ml min-1. The system was optimised by tuning the capillary and tube lens with a concentrated solution of FP. The recovery of FP from human plasma was 86.3%. Linearity of response was obtained over the concentration range 0.2-4.0 ng ml-1. The intra-assay and inter-assay variability were 6.3 and 2.9%, respectively. The lower limit of quantification was 0.2 ng ml-1 when a solid-phase extraction preceded the HPLC/APCI/MS.

Lack of effect of high doses of inhaled morphine on exercise endurance in chronic obstructive pulmonary disease

Systemic opiates may relieve dyspnoea and improve exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). Small doses of inhaled opiates may have similar effects; however, recent studies have shown no benefit. We studied higher doses of inhaled morphine and measured systemic absorption to determine whether any beneficial actions are local or systemic. Twenty and 40 mg doses and 0.9% saline were nebulized in a randomized, double-blind study of 16 patients with stable COPD. Patients performed 6 min walk tests immediately after the nebulized test solution (Walk 1) and again 60 min later (Walk 2). Arterial oxygen saturation (Sa,O2), modified Borg dyspnoea score and cardiac frequency were recorded during each walk. There was no difference between placebo and either dose of nebulized morphine on these measurements. The higher dose of nebulized morphine achieved a higher plasma concentration. The highest plasma concentration was measured immediately after nebulization, and this decreased steadily in the hour thereafter (p<0.002). There was no correlation between the change in walk distance and the change in plasma morphine concentration after either dose of nebulized morphine. We conclude that higher doses of nebulized morphine do not improve exercise endurance or relieve dyspnoea in patients with chronic obstructive pulmonary disease, and that morphine is rapidly absorbed systemically after inhalation.

Effect of regular inhaled salbutamol on airway responsiveness and airway inflammation in rhinitic non-asthmatic subjects

BACKGROUND

Regular, inhaled beta 2 agonists may increase airway responsiveness in asthmatic subjects. The mechanism is not known but may be via an increase in airway inflammation. A study was undertaken to examine the effect of regular inhaled salbutamol on airway responsiveness to methacholine and hypertonic saline, on the maximal response plateau to methacholine, and on inflammatory cells in induced sputum in rhinitic non-asthmatic subjects.

METHODS

Thirty subjects with a baseline maximal response plateau of > 15% fall in forced expiratory volume in one second (FEV1) entered a randomised, placebo controlled, parallel trial consisting of two weeks run in, four weeks of treatment, and two weeks washout. Methacholine challenges were performed at the beginning of the run in period, before treatment, after treatment, and after washout. Hypertonic saline challenges were performed before and after treatment and induced sputum samples were collected for differential cell counting.

RESULTS

There was no change in airway responsiveness, maximal response plateau to methacholine, or in induced sputum eosinophils or mast cells. The maximum fall in FEV1 after hypertonic saline increased in the salbutamol group (median change 6.0%, interquartile range (IQR) 11.0) but did not change in the placebo group (median change 1.3%, IQR 5.5).

CONCLUSIONS

Regular inhaled salbutamol for four weeks increases airway responsiveness to hypertonic saline but does not alter airway responsiveness to methacholine or cells in induced sputum in non-asthmatic individuals with rhinitis. The relevance of these findings to asthmatic subjects has not been established.

The mechanism of excretion of paraquat in rats

Paraquat (PQ)(1,1'-dimethyl-4,4'-bipyridinium) is a toxic herbicidal cation. The renal excretory mechanisms of PQ and its interactions with organic cations and anions were investigated in anaesthetised rats. The renal clearance of PQ was studied in male Wistar rats using inulin as the marker of glomerular filtration rate. The fractional excretion of paraquat (FEpq) decreased from 2.1+/-0.01 to 1.2+/-0.03 as the plasma concentration rose from 0.4+/-0.02 to 21.2+/-1.6 microM. These results demonstrated that the excretion of PQ was greater than glomerular filtration, concentration dependent and saturable, indicating that it was secreted by an active transport system. The excretion of PQ was dependent predominantly on the glomerular filtration rate with a small secretory component (Km = 8.5+/-3.1 microM, Vmax = 114+/-19 nmol/kg per min). The clearance of PQ was not inhibited by high doses of cimetidine, or p-aminohippurate. However, quinine (P = 0.001) and N-methylnicotinamide (NMN) (P = 0.03) reduced the FEpq, suggesting that they share a similar cation transport system with PQ. In summary, PQ is actively secreted by the rat kidney via a cation transport system.

Effect of inhaled frusemide and oral indomethacin on the airway response to hypertonic saline challenge in asthmatic subjects

BACKGROUND

Inhaled frusemide inhibits airway narrowing and causes a transient increase in forced expiratory volume in one second (FEV1) during hypertonic saline challenge. This inhibitory effect could be secondary to prostaglandin release during challenge. The involvement of prostaglandins in the inhibitory action of frusemide during challenge with 4.5% NaCl was investigated by premedicating with indomethacin, a prostaglandin synthetase inhibitor.

METHODS

Fourteen asthmatic subjects (eight women) aged 26.6 (range 18-56) years participated in a double blind, placebo controlled, crossover study. The subjects attended five times and inhaled 4.5% NaCl for 0.5, 0.75, 1, 1.5, 2, 4, 8, 8, and 8 minutes, or part thereof, or until a provocative dose causing a 20% fall in FEV1 (PD20 FEV1) was recorded. Indomethacin (100 mg/day) or placebo were taken three days before all visits, except control day. The FEV1 was measured and frusemide (38.0 (6.4) mg, pH = 9) or vehicle (0.9% NaCl, pH = 9) were inhaled 10 minutes before the challenge. Bronchodilation was calculated as the percentage rise in FEV1 from the prechallenge FEV1 to the highest FEV1 recorded during the challenge.

RESULTS

Frusemide caused a fold increase in PD20 FEV1 compared with the vehicle which was similar in the presence of both indomethacin and placebo (3.7 (95% CI 2.0 to 7.3) versus 3.3 (2.0 to 5.4)). Frusemide, but not vehicle, also caused a transient percentage rise in FEV1 during challenge with 4.5% NaCl which was not blocked by indomethacin (3.6% (1.2 to 6.0)) or placebo (3.1% (1.0 to 5.2)).

CONCLUSIONS

Inhaled frusemide inhibited airway narrowing and caused a transient increase in FEV1 during challenge with 4.5% NaCl. These effects were not blocked by indomethacin, which suggests that the inhibitory action of frusemide is not secondary to prostaglandin release.

Characterisation and uptake of paraquat by rat renal proximal tubular cells in primary culture

1 Uptake of the herbicide paraquat (PQ), by rat proximal tubular cells (PTC) in primary culture grown on a collagen coated support was investigated. 2 The uptake of PQ by PTC was predominantly from the basolateral side. The basolateral uptake of PQ was saturable with time and increasing concentrations, energy dependent and could be inhibited by certain organic cations. Using Michaelis Menten kinetics, the apparent K(m) was 778 +/- 241 microM and Vmax was 0.97 +/- 0.24 pmol/microgram protein/15 min for the basolateral uptake of PQ. Cimetidine (5.7 +/- 0.4 pg/microgram protein/ 30 min, P < 0.001) was the most potent inhibitor of PQ uptake, followed by quinine (6.5 +/- 0.4 pg/microgram protein/30 min, P < 0.01) and then tetraethylammonium (8.2 +/- 0.5 pg/microgram protein/30 min, P < 0.05) when compared with control (11 +/- 1 pg/microgram protein/30 min). N-methylnicotinamide, p-aminohippurate and putrescine did not inhibit the basolateral uptake of PQ. The sodium hydrogen exchange inhibitors, amiloride and its analogue, 5-(N,N hexamethylene) amiloride (HMA) inhibited both the apical and basolateral uptake of PQ. 3 The apical uptake of PQ was not saturable with increasing concentrations and was not inhibited by 2,4-dinitrophenol, but it was reduced by cimetidine (P < 0.01), quinine (P < 0.05) and a sodium potassium ATPase inhibitor, ouabain (P < 0.01). 4 It is concluded that PQ was taken up from the basolateral side of primary cultured rat PTC by an energy dependent transport system.

Transport of paraquat in a renal epithelial cell line LLC-PK1

Transport of paraquat (PQ), a cationic herbicide, was investigated in a proximal renal epithelial cell line, LLC-PK1. Collagencoated permeable filters were used to study the direction of PQ transport. PQ was transported predominantly from the basolateral to apical (B-->A) membrane of these cells. The B-->A flux and uptake of PQ were saturable with time and increasing concentrations, energy dependent and inhibited by several cations. Quinine was the most potent inhibitor of basolateral PQ uptake, followed by cimetidine and then tetraethylammonium acetate (P < .0001). The noninhibitable basolateral uptake of PQ has an apparent K(m) of 357 microM and a Vmax of 1.47 pmol/micrograms protein/2 min. For flux studies, only quinine inhibited the B-->A flux of PQ (P = .02). Putrescine, p-aminohippurate, probenecid, N-methylnicotinamide and choline did not inhibit the flux or uptake of PQ. 5-N,N-Hexamethylene amiloride, a cationic amiloride analog and a potent inhibitor of the Na/H exchanger, significantly inhibited the uptake of PQ from either side (P < .0001). Acidic pH in the apical medium inhibited the uptake of PQ from either side. The studies demonstrated that PQ was actively transported by the LLC-PK1 cells. PQ shared a similar transport system with several cations, which appeared to have a more significant inhibition on the transcellular uptake than the flux of PQ.

Determination of epimers 22R and 22S of budesonide in human plasma by high-performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

A highly sensitive and selective method has been developed for the simultaneous quantification of 22R- and 22S-epimers of budesonide in human plasma. The drug was isolated from human plasma using C18 solid-phase extraction cartridges and was acetylated with a mixture of 12.5% acetic anhydride and 12.5% triethylamine in acetonitrile to form the 21-acetyl derivatives. Deuterium-labelled budesonide was synthesized and determined to have an isotopic purity > 99%. This was used as the internal standard. Epimers were quantified by automated liquid chromatography-atmospheric pressure chemical ionization mass spectrometry, operating in selected ion mode at m/z 473.2 and m/z 476.2. Linear responses were observed for both epimers over the range 0.25 to 10.0 ng/ml. The average recoveries of 22R- and 22S-epimers of budesonide from human plasma were 87.4% and 87.0%, respectively. The lower limit of quantification for each epimer was 0.25 ng/ml, corresponding to 50.0 pg of analyte on column. Within- and between-day coefficients of variation were 8.6% and 4.0%, respectively.

Mucociliary clearance during and after isocapnic hyperventilation with dry air in the presence of frusemide

We have previously shown that mucociliary clearance (MCC) decreased during and increased after isocapnic hyperventilation (ISH) with dry air, both in asthmatic and healthy subjects. Inhaled frusemide, an inhibitor of the Na+/K+/2Cl- and NaCl co-transporters on the basolateral membrane of the epithelial cell, prevents the airway narrowing provoked by ISH with dry air. The co-transport system controls epithelial cell volume and chloride secretion and, thus, frusemide has the potential to modify the rate of recovery of periciliary fluid volume during and after ISH with dry air, and hence affect MCC. Frusemide also blocks mediator release from mast cells, which may also modify the increase in MCC after ISH. Eleven asthmatic and 11 healthy subjects inhaled frusemide (35.7 +/- 0.44 mg) or its vehicle, from a Fisoneb ultrasonic nebulizer 30 min before ISH with dry air, on two separate occasions. MCC was measured using 99mTc-sulphur colloid and a gamma camera. Frusemide, compared to its vehicle, did not affect MCC during or 45 min after ISH. However, in the presence of frusemide, the onset of the increase of MCC after ISH was significantly delayed for approximately 10 min in the whole right lung (p < 0.002) and central region (p < 0.01) in the asthmatic but not in the healthy subjects. These findings could be explained by frusemide delaying the recovery of the periciliary fluid volume after ISH with dry air and/or interfering with the stimulus that causes the increase in MCC in the asthmatic subjects after ISH.

Inhalation of hypertonic saline aerosol enhances mucociliary clearance in asthmatic and healthy subjects

Hyperosmolarity of the airway surface liquid (ASL) has been proposed as the stimulus for hyperpnoea-induced asthma. We found previously that mucociliary clearance (MCC) was increased after isocapnic hyperventilation (ISH) with dry air, and we proposed that the increase related to transient hyperosmolarity of the ASL. We investigated the effect of increasing the osmolarity of the ASL on MCC, by administering an aerosol of concentrated salt solution. MCC was measured using 99mTc-sulphur colloid, gamma camera and computer analysis in 12 asthmatic and 10 healthy subjects on three separate days, involving administration of each of the following: 1) ultrasonically nebulized 14.4% saline; 2) ultrasonically nebulized 0.9% saline; and 3) no aerosol intervention (control). The (mean +/- SD) volume of nebulized 14.4% saline was 2.2 +/- 1.2 mL for asthmatics and 3.2 +/- 0.7 mL for healthy subjects. This volume was delivered over a period of 5.4 +/- 1.3 and 6.4 +/- 0.7 min for asthmatic and healthy subjects, respectively. The airway response to 14.4% saline was assessed on a separate visit and the fall in forced expiratory volume in one second (FEV1) was 22 +/- 4% in the asthmatic and 3 +/- 2% in the healthy subjects. Compared to the MCC with the 0.9% saline and control, the hypertonic aerosol increased MCC in both groups. In asthmatic subjects, MCC of the whole right lung in 1 h was 68 +/- 10% with 14.4% saline vs 44 +/- 14% with 0.9% saline and 39 +/- 13% with control. In healthy subjects, MCC of the whole right lung in 1 h was 53 +/- 12% with 14.4% saline vs 41 +/- 15% with 0.9% saline and 36 +/- 13% with control. We conclude that an increase in osmolarity of the airway surface liquid increases mucociliary clearance both in asthmatic and healthy subjects. These findings are in keeping with our previous suggestion that the increase in mucociliary clearance after isotonic hyperventilation with dry air is due to a transient hyperosmolarity of the airway surface liquid.

Gender differences in medical presentation and detection of patients with a history of alcohol abuse or dependence

Women and men with alcohol use disorders differ in many respects. A retrospective medical record review of 132 patients was performed to determine outpatient clinic utilization, presentation patterns and physician actions related to patient gender and lifetime DIS-status. Women, irrespective of DIS-status, utilized out-patient health care services more often than did DIS-positive or negative men. Of 16 specific alcohol-related complaints, gender differences were only detected for trauma. DIS-positive men were more likely to have had an alcohol history taken during the preceding 12 months than were DIS-positive women. Sedatives/minor tranquilizers were most often prescribed to DIS-positive women. This study supports the need in primary care settings for more screening to detect and diagnose alcohol-abusing patients, particularly women. Physicians should routinely screen for alcohol abuse before prescribing sedatives or minor tranquilizers.

Better medication compliance is associated with improved control of childhood asthma

Our previous studies have shown that medication compliance in children prescribed continuous treatment for asthma is poor, and that an intervention can improve the level of compliance. The present study examined the effects of an intervention on the clinical course of moderately severe asthma. At each of six clinic visits, spirometry was performed, medication compliance was assessed by questionnaire, and the physicians made an overall assessment of asthma severity (Severity Score) and provided a score for asthma control (Control of Asthma Score). Peak expiratory flow rates were measured twice daily for one month prior to each clinic visit, and the coefficient of variation (% CV) was calculated. Subjects received the intervention after at least two visits, and 53 of the 78 recruits completed the study. Following the intervention, % CV, Control of Asthma Score, Severity Score and % compliance improved, showing that better medication compliance was associated with better control of moderately severe asthma.

Psychiatric problems experienced by primary care patients who misuse alcohol

Of 1936 primary care patients screened using the alcohol portion of the Diagnostic Interview Schedule, 100 met criteria for "alcohol abuse and/or dependence." Sixty of the individuals who misused alcohol were matched to 60 who did not. All 160 patients answered questions about psychiatric symptoms and psychotropic drug use. The lifetime prevalence of depression, suicidal thoughts, suicidal attempts, violent behavior, and trouble concentrating was consistently higher for those who misused alcohol. Depression and trouble concentrating were more likely to be experienced by alcohol misusers during the past month. Gender differences were also noted for prevalence of psychiatric symptoms.

Different effects of inhaled amiloride and frusemide on airway responsiveness to dry air challenge in asthmatic subjects

Amiloride, a Na+ channel blocker, and frusemide, an inhibitor of the Na+/K+/2Cl- co-transporter on the basolateral surface of airway epithelial cells, have the potential to affect water transport across the airway epithelium. As isocapnic hyperventilation challenge (ISH) with dry air may provoke airway narrowing in asthmatic subjects by dehydrating the airways, inhaled amiloride and frusemide may reduce airway responsiveness by effecting airway hydration. Fifteen asthmatic subjects (6 females, 9 males), who had a fall in forced expiratory volume in one second (FEV1) of 20% after ISH, inhaled amiloride (11 mg), or its vehicle, from a Fisoneb ultrasonic nebulizer, within 10 min before ISH. On a separate day, eight of these subjects inhaled frusemide (38 mg), from the same Fisoneb, 10 min before ISH. After breathing, 30 l at resting ventilation, subjects breathed at 30% of their maximum voluntary ventilation (MVV i.e. predicted FEV1x35), then at 60% MVV, and finally at MVV for 3 or 4 min. FEV1 was measured 1, 3, 5, 7 and 9 min after each period, or until it was stable. Airway sensitivity was expressed as the ventilation (l-min-1) which provoked a 10, 15, 20 or 30% fall in FEV1, (PVE10, PVE15, PVE20 and PVE30, respectively). There was no significant difference in the PVE10,15,20,30 between the vehicle and amiloride treatment day; however, in the 8 subjects who inhaled frusemide, frusemide caused a significant increase in the PVE20 when compared to amiloride. In conclusion, inhaled amiloride failed to protect against ISH, whereas frusemide was effective at reducing airway responsiveness. Further studies are needed to explain the mechanism of action of frusemide.