Sexually Dimorphic Adolescent Trajectories of Prefrontal Endocannabinoid Synaptic Plasticity Equalize in Adulthood, Reflected by Endocannabinoid System Gene Expression

Introduction: How sex influences prefrontal cortexes (PFCs) synaptic development through adolescence remains unclear. Materials and Methods: In this study we describe sex-specific cellular and synaptic trajectories in the rat PFC from adolescence to adulthood. Results: The excitability of PFC layer 5 pyramidal neurons was lower in adult females compared with other developmental stages. The developmental course of endocannabinoid-mediated long-term depression (eCB-LTD) was sexually dimorphic, unlike long-term potentiation or mGluR3-LTD. eCB-LTD was expressed in juvenile females but appeared only at puberty in males. Endovanilloid TRPV1R or eCB receptors were engaged during LTD in a sequential and sexually dimorphic manner. Gene expression of the eCB/vanilloid systems was sequential and sex specific. LTD-incompetent juvenile males had elevated expression levels of the CB1R-interacting inhibitory protein cannabinoid receptor interacting protein 1a and of the 2-arachidonoylglycerol-degrading enzyme ABHD6. Pharmacological inhibition of ABHD6 or MAGL enabled LTD in young males, whereas inhibition of anandamide degradation was ineffective. Conclusions: These results reveal sex differences in the maturational trajectories of the rat PFC.

Prenatal Δ9-Tetrahydrocannabinol Exposure in Males Leads to Motivational Disturbances Related to Striatal Epigenetic Dysregulation

BACKGROUND

Cannabis remains one of the most widely abused drugs during pregnancy. In utero exposure to its principal psychoactive component, Δ⁹-tetrahydrocannabinol (THC), can result in long-term neuropsychiatric risk for the progeny. This study investigated epigenetic signatures underlying these enduring consequences.

METHODS

Rat dams were exposed daily to THC (0.15 mg/kg) during pregnancy, and adult male offspring were examined for reward and depressive-like behavioral endophenotypes. Using unbiased sequencing approaches, we explored transcriptional and epigenetic profiles in the nucleus accumbens (NAc), a brain area central to reward and emotional processing. An in vitro CRISPR (clustered regularly interspaced short palindromic repeats) activation model coupled with RNA sequencing was also applied to study specific consequences of epigenetic dysregulation, and altered molecular signatures were compared with human major depressive disorder transcriptome datasets.

RESULTS

Prenatal THC exposure induced increased motivation for food, heightened learned helplessness and anhedonia, and altered stress sensitivity. We identified a robust increase specific to males in the expression of Kmt2a (histone-lysine N-methyltransferase 2A) that targets H3K4 (lysine 4 on histone H3) in cellular chromatin. Normalizing Kmt2a in the NAc rescued the motivational phenotype of prenatally THC-exposed animals. Comparison of RNA- and H3K4me3-sequencing datasets from the NAc of rat offspring with the in vitro model of Kmt2a upregulation revealed overlapping, significant disturbances in pathways that mediate synaptic plasticity. Similar transcriptional alterations were detected in human major depressive disorder.

CONCLUSIONS

These studies provide direct evidence for the persistent effects of prenatal cannabis exposure on transcriptional and epigenetic deviations in the NAc via Kmt2a dysregulation and associated psychiatric vulnerability.

Cannabis and synaptic reprogramming of the developing brain

Recent years have been transformational in regard to the perception of the health risks and benefits of cannabis with increased acceptance of use. This has unintended neurodevelopmental implications given the increased use of cannabis and the potent levels of Δ⁹-tetrahydrocannabinol today being consumed by pregnant women, young mothers and teens. In this Review, we provide an overview of the neurobiological effects of cannabinoid exposure during prenatal/perinatal and adolescent periods, in which the endogenous cannabinoid system plays a fundamental role in neurodevelopmental processes. We highlight impaired synaptic plasticity as characteristic of developmental exposure and the important contribution of epigenetic reprogramming that maintains the long-term impact into adulthood and across generations. Such epigenetic influence by its very nature being highly responsive to the environment also provides the potential to diminish neural perturbations associated with developmental cannabis exposure.

Sex Differences in the Behavioral and Synaptic Consequences of a Single in vivo Exposure to the Synthetic Cannabimimetic WIN55,212-2 at Puberty and Adulthood

Heavy cannabis consumption among adolescents is associated with significant and lasting neurobiological, psychological and health consequences that depend on the age of first use. Chronic exposure to cannabinoid agonists during the perinatal period or adolescence alters social behavior and prefrontal cortex (PFC) activity in adult rats. However, sex differences on social behavior as well as PFC synaptic plasticity after acute cannabinoid activation remain poorly explored. Here, we determined that the consequences of a single in vivo exposure to the synthetic cannabimimetic WIN55,212-2 differently affected PFC neuronal and synaptic functions after 24 h in male and female rats during the pubertal and adulthood periods. During puberty, single cannabinoid exposure (SCE) reduced play behavior in females but not males. In contrast, the same treatment impaired sociability in both sexes at adulthood. General exploration and memory recognition remained normal at both ages and both sexes. At the synaptic level, SCE ablated endocannabinoid-mediated synaptic plasticity in the PFC of females of both ages and heightened excitability of PFC pyramidal neurons at adulthood, while males were spared. In contrast, cannabinoid exposure was associated with impaired long-term potentiation (LTP) specifically in adult males. Together, these data indicate behavioral and synaptic sex differences in response to a single in vivo exposure to cannabinoid at puberty and adulthood.

Sex-dependent effects of in utero cannabinoid exposure on cortical function

Cannabinoids can cross the placenta, thus may interfere with fetal endocannabinoid signaling during neurodevelopment, causing long-lasting deficits. Despite increasing reports of cannabis consumption during pregnancy, the protracted consequences of prenatal cannabinoid exposure (PCE) remain incompletely understood. Here, we report sex-specific differences in behavioral and neuronal deficits in the adult progeny of rat dams exposed to low doses of cannabinoids during gestation. In males, PCE reduced social interaction, ablated endocannabinoid long-term depression (LTD) and heightened excitability of prefrontal cortex pyramidal neurons, while females were spared. Group 1 mGluR and endocannabinoid signaling regulate emotional behavior and synaptic plasticity. Notably, sex-differences following PCE included levels of mGluR1/5 and TRPV1R mRNA. Finally, positive allosteric modulation of mGlu5 and enhancement of anandamide levels restored LTD and social interaction in PCE adult males. Together, these results highlight marked sexual differences in the effects of PCE and introduce strategies for reversing detrimental effects of PCE.

Oral xanthines as maintenance treatment for asthma in children

BACKGROUND

Xanthines have been used in the treatment of asthma as a bronchodilator, though they may also have anti-inflammatory effects. The current role of xanthines in the long-term treatment of childhood asthma needs to be reassessed.

OBJECTIVES

To determine the efficacy of xanthines (e.g. theophylline) in the maintenance treatment of paediatric asthma.

SEARCH STRATEGY

A search of the Cochrane Airways Group Specialised Register was undertaken with predefined search terms. Searches are current to May 2005.

SELECTION CRITERIA

Randomised controlled trials,lasting at least four weeks comparing a xanthine with placebo, regular short-acting beta-agonist (SABA), inhaled corticosteroids (ICS), cromoglycate (SCG), ketotifen (KET) or leukotriene antagonist, in children with diagnosed with chronic asthma between 18 months and 18 years old.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected each study for inclusion in the review and extracted data. Primary outcome was percentage of symptom-free days.

MAIN RESULTS

Thirty-four studies (2734 participants) of adequate quality were included. Xanthine versus placebo (17 studies): The proportion of symptom free days was larger with xanthine compared with placebo (7.97% [95% CI 3.41, 12.53]). Rescue medication usage was lower with xanthine, with no significant difference in symptom scores or hospitalisations. FEV1 , and PEF were better with xanthine. Xanthine was associated with non - specific side-effects. Data from behavioural scores were inconclusive. Xanthine versus ICS (four studies) : Exacerbations were less frequent with ICS, but no significant difference on lung function was observed. Individual studies reported significant improvements in symptom measures in favour of steroids, and one study reported a difference in growth rate in favour of xanthine. No difference was observed for study withdrawal or tremor. Xanthine was associated with more frequent headache and nausea. Xanthine versus regular SABA (10 studies): No significant difference in symptoms, rescue medication usage and spirometry. Individual studies reported improvement in PEF with beta-agonist. Beta-agonist treatment led to fewer hospitalisations and headaches. Xanthine was associated with less tremor. Xanthine versus SCG (six studies ): No significant difference in symptoms, exacerbations and rescue medication. Sodium cromoglycate was associated with fewer gastro-intestinal side-effects than xanthine. Xanthine versus KET (one study): No statistical tests of significance between xanthine and ketotifen were reported. Xanthine + ICS versus placebo + same dose ICS (three studies) : Results were conflicting due to clinical/methodological differences, and could not be aggregated.

AUTHORS' CONCLUSIONS

Xanthines as first-line preventer alleviate symptoms and reduce requirement for rescue medication in children with mild to moderate asthma. When compared with ICS they were less effective in preventing exacerbations. Xanthines had similar efficacy as single preventative agent compared with regular SABA and SCG. Evidence on AEs (adverse effects) was equivocal: there was evidence for increased AEs overall, but no evidence that any specific AE (including effects on behaviour and attention) occurred more frequently than with placebo. There is insufficient evidence from available studies to make firm conclusions about the effectiveness of xanthines as add-on preventative treatment to ICS, and there are no published paediatric studies comparing xanthines with alternatives in this role. Our data suggest that xanthines are only suitable as first-line preventative asthma therapy in children when ICS are not available. They may have a role as add-on therapy in more severe asthma not controlled by ICS, but further studies are needed to examine this, and to define the risk-benefit ratio compared with other agents.

Azathioprine as an oral corticosteroid sparing agent for asthma

BACKGROUND

For the majority of chronic asthmatics, symptoms are best controlled by using inhaled steroids. However, for a small group of asthmatics, symptoms can only be controlled by high doses of oral steroids. Continuous use of oral steroid is associated with severe side-effects, but it has been suggested that azathioprine, an immunosuppressive anti-metabolite, often used to reduce the immune response in chronic active hepatitis and severe rheumatoid arthritis, could be useful as an oral steroid sparing agent. There is a need to systematically evaluate the evidence regarding its use to reduce or eliminate oral corticosteroid usage.

OBJECTIVES

The objective of this review is to assess the efficacy of adding azathioprine in patients with stable asthma who are dependent on oral corticosteroids with the intention of eventually minimizing or eliminating the use of these steroids.

SEARCH STRATEGY

Searches of the Cochrane Airways Group asthma and wheeze trials register were undertaken with predefined search terms. Searches were current as of February 2003

SELECTION CRITERIA

Only studies with a randomised placebo-controlled design met the inclusion criteria for the review.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for suitability for inclusion in the review. Data were extracted and entered into RevMan 4.2.2.

MAIN RESULTS

Two small trials recruiting 23 participants met the inclusion criteria for the review. Participants may have been suffering from comorbid lung disease. No data on oral steroid consumption were reported. No significant differences were observed in the studies for FEV(1), FVC, PaO(2) and symptoms. One study reported a statistically significant difference in SGaw, but the clinical importance of this is uncertain. Due to concerns over the small sample sizes and methodological shortcomings in terms of inadequate washout in one study, and methods used in outcome assessment for both studies, the findings of the studies are not generalisable to the issue of steroid tapering.

REVIEWER'S CONCLUSIONS

Currently there is a clear lack of evidence to support the use of azathioprine in the treatment of chronic asthma as a steroid sparing-agent. Large, long-term studies with pre-defined steroid reducing protocols are required before recommendations for clinical practice can be made.

Colchicine as an oral corticosteroid sparing agent for asthma

BACKGROUND

Oral corticosteroids are used as a treatment for asthma, but they are often associated with serious side effects. Colchicine is an anti-inflammatory, immuno modulating agent, which could potentially have a beneficial effect in the treatment of asthma as well as act as a steroid-sparing agent.

OBJECTIVES

To determine the effectiveness of colchicine as an oral corticosteroid sparing agent for in the treatment of chronic asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register (November 2002), SIGLE (1980 to 2001) and reference lists of potential articles. We also contacted researchers in the field.

SELECTION CRITERIA

Randomised controlled trials investigating the addition of colchicine compared to placebo in stable steroid dependent asthmatics.

DATA COLLECTION AND ANALYSIS

No trials were found that met the inclusion criteria.

MAIN RESULTS

We were unable to perform any meta-analyses. Two small studies have assessed the efficacy of colchicine subsequent to inhaled steroid withdrawal and as a tapering agent in inhaled steroids. Both studies failed to detect a significant difference between colchicine and placebo.

REVIEWER'S CONCLUSIONS

No relevant trials have been published, so there is no evidence to indicate that colchicine is beneficial or otherwise in the management of steroid-dependent asthmatic patients. There is a need for well designed randomised controlled trials to be performed.

Chloroquine as a steroid sparing agent for asthma

BACKGROUND

For the majority of chronic asthmatics, symptoms are best controlled using inhaled steroids, but for a small group of asthma sufferers, symptoms cannot be controlled using inhaled steroids and instead continuous use of high dosage oral steroids (corticosteroids) are required. However, using high dosage oral steroids for long periods is associated with severe side effects. Steroid-sparing treatments have been sought and one of these is chloroquine. Chloroquine is an anti-inflammatory agent, also used in the treatment of malarial infection and as a second-line therapy in the treatment of rheumatoid arthritis, sarcoidosis and systemic lupus erythematosus. All these diseases are associated with immunologic abnormalities hence the speculation that chloroquine might be used to control severe, poorly controlled bronchial asthma. There is a need to systematically evaluate the evidence regarding its use to reduce or eliminate oral corticosteroid use in asthma.

OBJECTIVES

The object of this review was to assess the efficacy of adding chloroquine to oral corticosteroids in patients with chronic asthma who are dependent on oral corticosteroids with the intention of minimising or eventually eliminating the use of these oral steroids.

SEARCH STRATEGY

Searches of the Cochrane Airways Group asthma and wheeze trials register were undertaken with predefined search terms in February 2003.

SELECTION CRITERIA

Only studies with a randomised placebo-controlled design met the inclusion criteria for the review.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed studies for suitable in the review. Data were extracted and entered into RevMan 4.2.2

MAIN RESULTS

One small study was included in the review. No significant findings were reported.

REVIEWER'S CONCLUSIONS

There is insufficient evidence to support the use of chloroquine as an oral steroid-sparing agent in chronic asthma. Further trials should optimise oral steroid dosage before addition of the steroid-sparing agent.

Holding chambers versus nebulisers for beta-agonist treatment of acute asthma

BACKGROUND

In acute asthma inhaled beta-2-agonists are often administered to relieve bronchospasm by wet nebulisation, but some have argued that metered-dose inhalers with a holding chamber (spacer) can be equally effective. In the community setting nebulisers are more expensive, require a power source and need regular maintenance.

OBJECTIVES

To assess the effects of holding chambers compared to nebulisers for the delivery of beta-2-agonists for acute asthma.

SEARCH STRATEGY

We last searched the Cochrane Airways Group trials register in November 2002 and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2002).

SELECTION CRITERIA

Randomised trials in adults and children (from two years of age) with asthma, where holding chamber beta-2-agonist delivery was compared with wet nebulisation.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied study inclusion criteria (one reviewer for the first version of the review), extracted the data and assessed trial quality. Missing data were obtained from the authors or estimated. Results are reported with 95% confidence intervals (CI).

MAIN RESULTS

This review has been updated in 2003 and has now analysed 1076 children and 444 adults included in 22 trials from emergency room and community settings. In addition, five trials on in-patients with acute asthma (184 children and 28 adults) have been added to the review. Method of delivery of beta-2-agonist did not appear to affect hospital admission rates. In adults, the relative risk of admission for holding chamber versus nebuliser was 0.88 (95% CI 0.56 to 1.38). The relative risk for children was 0.65 (95% CI 0.4 to 1.06). In children, length of stay in the emergency department was significantly shorter when the holding chamber was used, with a weighted mean difference of -0.47 hours, (95% CI -0.58 to -0.37 hours). Length of stay in the emergency department for adults was similar for the two delivery methods. Peak flow and forced expiratory volume were also similar for the two delivery methods. Pulse rate was lower for holding chamber in children, weighted mean difference -7.6% baseline (95% CI -9.9 to -5.3% baseline).

REVIEWER'S CONCLUSIONS

Metered-dose inhalers with holding chamber produced outcomes that were at least equivalent to nebuliser delivery. Holding chambers may have some advantages compared to nebulisers for children with acute asthma.

Humidity control for chronic asthma

BACKGROUND

Humidity control measures in the home environment of patients with asthma have been recommended, however there is no consensus about the usefulness of these measures.

OBJECTIVES

To study the effect of dehumidification of the home environment on asthma control.

SEARCH STRATEGY

A search of the clinical trials registers of the Cochrane Collaboration and Cochrane Airways Group using search terms for asthma and [humid* OR water vapour OR water vapor* OR water-vapour* OR water-vapor*].

SELECTION CRITERIA

Randomized controlled trials on the use of humidity control measures in the home environment of patients with asthma were evaluated for inclusion. Only one trial could be included.

DATA COLLECTION AND ANALYSIS

Data was extracted using a predesigned data extraction form. No data was available for entering into RevMan for analysis.

MAIN RESULTS

The included trial using mechanical ventilation with or without high efficiency vacuum cleaners did not show any clinical benefit to asthma patients. There was a decline in the house dust mite count and the antigen level. This open trial had a low sample size.

REVIEWER'S CONCLUSIONS

There is a need for studying the health benefits of dehumidification by a double blind randomized controlled trial with adequate sample size measuring clinical outcomes in patients of asthma.

Dapsone as an oral corticosteroid sparing agent for asthma

BACKGROUND

Oral corticosteroids are used as a treatment for asthma, however they are often associated with serious side effects. Dapsone is a sulfone with anti-inflammatory properties, therefore it may have a beneficial effect in the treatment of asthma and act as a corticosteroid-sparing agent.

OBJECTIVES

The objective of this review is to assess the safety and efficacy of adding dapsone to oral corticosteroids in adults with stable asthma who are dependent on oral corticosteroids with the intention of eventually minimizing or eliminating the use of these steroids.

SEARCH STRATEGY

The Cochrane Airways group trials register and reference lists of potential articles were searched.

SELECTION CRITERIA

Randomised controlled trials investigating the addition of dapsone compared to placebo in stable corticosteroid dependent asthmatics.

DATA COLLECTION AND ANALYSIS

No trials were found that met the selection criteria.

MAIN RESULTS

No meta-analyses could be performed.

REVIEWER'S CONCLUSIONS

No randomised controlled trials have been published, so there is no reliable evidence to show whether dapsone is beneficial or otherwise in the management of steroid-dependent asthmatic patients. There is a need for well designed randomised controlled trials to be performed. These must be carried out double-blind, since oral corticosteroid reduction requires a judgement on the part of the physician, who may be open to bias if the treatment allocation is known.

Anticholinergic drugs for wheeze in children under the age of two years

BACKGROUND

Wheeze in infancy and early childhood is common and appears to be increasing though the magnitude of any increase is unclear. Most wheezing episodes in infancy are precipitated by respiratory viral infections. Treatment of very young children with wheeze remains controversial. Anti-cholinergics are often prescribed but practice varies widely and the efficacy of this form of therapy remains the subject for debate.

OBJECTIVES

Wheeze in infancy and early childhood is common and appears to be increasing. Most wheezing episodes in infancy are a result of viral infection. Bronchodilator medications such as beta2-agonists and anti-cholinergic agents are often used to relieve symptoms, but patterns of use vary. The objective of this review was to assess the effects of anti-cholinergic therapy in the treatment of wheezing infants.

SEARCH STRATEGY

We searched the Cochrane Airways Group trials register and the reference lists of articles. We contacted researchers in the field and industry sources.

SELECTION CRITERIA

Randomised trials that compared anti-cholinergic therapy with placebo or beta2-agonists in wheezing children under two years of age. Children with acute bronchiolitis and chronic lung disease were excluded.

DATA COLLECTION AND ANALYSIS

Eligibility for inclusion and quality of trials were assessed independently by two reviewers.

MAIN RESULTS

Six trials involving 321 infants in three different settings were included. Compared with beta2-agonist alone, the combination of ipratropium bromide and beta2-agonist was associated with a reduced need for additional treatment, but no difference was seen in treatment response, respiratory rate or oxygen saturation improvement in the emergency department. There was no significant difference in length of hospital stay between ipratropium bromide and placebo; or between ipratropium bromide and beta2-agonist combined compared with beta2-agonist alone. However, combined ipratropium bromide and beta2-agonist compared to placebo showed significantly improved clinical scores at 24 hours. Parents preferred ipratropium bromide over nebulised water or placebo for relief of their children's symptoms at home.

REVIEWER'S CONCLUSIONS

There is not enough evidence to support the uncritical use of anti-cholinergic therapy for wheezing infants, although parents using it at home were able to identify benefits.

Long-acting beta2-agonists for chronic obstructive pulmonary disease patients with poorly reversible airflow limitation

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterised by partially reversible airflow limitation. Many patients have little reversibility to short acting bronchodilators, but long acting bronchodilators are frequently advocated.

OBJECTIVES

To determine the effectiveness of long acting beta-2 adrenoceptor agonists in COPD patients with low reversibility to short-acting bronchodilators.

SEARCH STRATEGY

The Cochrane Airways Group register was searched. Bibliographies of identified randomised controlled trials (RCTs) were also searched. Authors of identified RCTs were contacted for other published and unpublished studies and unpublished studies were obtained from pharmaceutical companies.

SELECTION CRITERIA

All RCTs over four weeks in duration comparing treatment with long-acting beta-2 adrenoceptor agonists (salmeterol or formoterol) with placebo in patients with stable poorly-reversible COPD.

DATA COLLECTION AND ANALYSIS

Data extraction and study quality assessment was performed independently by two reviewers. Where further or missing data were required, authors of studies were contacted.

MAIN RESULTS

Eight RCTs met the inclusion criteria review. Six were parallel group studies of 12-16 weeks in duration and two were cross-over studies with four week treatment arms. All eight assessed the efficacy of salmeterol in COPD compared to placebo. Few of the results could be combined in meta-analyses because of differences in methods of reporting data. Isolated trials reported an improvement in one or other outcome in favour of salmeterol, but the only possible meta-analysis of FEV1 showed no overall benefit (Standardised mean difference 0.14 (95% Confidence Interval -0.16, 0.44, n=4). There was no consistent effect on Health Related Quality of LIfe or symptoms scores. Overall, breathlessness was not reduced, but in one study more subjects in the salmeterol group had low Borg dyspnoea scores compared to placebo (Peto Odds Ratio = 0.60, 95% CI: 0.40; 0.88). There was no effect on COPD exacerbations over the short period of the studies.

REVIEWER'S CONCLUSIONS

In the few studies that could be included in this review, treatment of patients with COPD with long acting beta-2 agonists produces only small increases in FEV1. The improvement in airways function does not seem to be associated with a consistent effect on other outcomes such as health related quality of life or reductions in breathlessness.

Short acting beta agonists for recurrent wheeze in children under 2 years of age

BACKGROUND

Wheeze is a common symptom in infancy and is a common cause for both primary care consultations and hospital admission. Beta2-adrenoceptor agonists (b2-agonists) are the most frequently used as bronchodilator but their efficacy is questionable.

OBJECTIVES

To determine the effectiveness of b2-agonist for the treatment of infants with recurrent and persistent wheeze.

SEARCH STRATEGY

Relevant trials were identified using the Cochrane Airways Group database (CENTRAL), Medline and Pubmed. The database search used the following terms: Wheeze or asthma and Infant or Child and Short acting beta-agonist or Salbutamol (variants), Albuterol, Terbutaline (variants), Orciprenaline, Fenoterol

SELECTION CRITERIA

Randomised controlled trials comparing the effect of b2-agonist against placebo in children under 2 years of age who had had two or more previous episodes of wheeze, not related to another form of chronic lung disease.

DATA COLLECTION AND ANALYSIS

Eight studies met the criteria for inclusion in this meta-analysis. The studies investigated patients in three settings: at home (3 studies), in hospital (2 studies) and in the pulmonary function laboratory (3 studies). The main outcome measure was change in respiratory rate except for community based studies where symptom scores were used.

MAIN RESULTS

The studies were markedly heterogeneous and between study comparisons were limited. Improvement in respiratory rate, symptom score and oxygen saturation were noted in one study in the emergency department following two salbutamol nebulisers but this had no impact on hospital admission. There was a reduction in bronchial reactivity following salbutamol. There was no significant benefit from taking regular inhaled salbutamol on symptom scores recorded at home.

REVIEWER'S CONCLUSIONS

There is no clear benefit of using b2-agonists in the management of recurrent wheeze in the first two years of life although there is conflicting evidence. At present, further studies should only be performed if the patient group can be clearly defined and there is a suitable outcome parameter capable of measuring a response.

[Clinical analysis of pneumonia treated at the hospital]

104 cases of pneumonia, treated in Department of Pulmonary Diseases of Military Medical Academy in the years 1995-1997, were analysed. Patients were divided into two groups. In the first group were 58 patients which had acute symptoms of pneumonia and the treatment was started in our department without any treatment before. In the second group were 45 patients which had acute symptoms two or three weeks before admission to hospital. In this period these patients received one or more antibiotics. The bacteriological findings and the periods of the treatment were analysed in these both groups.

[An increase of nonspecific airway hyperreactivity after repeated challenge with subthreshold doses of allergen in asthma patients]

The study was performed in 11 patients suffering from stable mild and moderate atopic asthma. Bronchial allergen challenges were performed according to Chai et al method. Airway hyperreactivity-AH (PC20H in mg/ml) was determined in each study day before subthreshold allergen inhalation dose, meaning the dose which did not induce asthmatic responses. Then FEV1 was measured in 2, 5, 15, 30 i 60 min. after allergen provocation throughout 4 to 9 consecutive days. A significant increase of PC20H was observed in 8 patients (xg PC20H in whole group decreased from 0.93 to 0.35 mg/ml after allergen challenges). The authors conclude that allergen inhalation challenge without asthmatic bronchial responses can cause an increase AH.

[The influence of multiple histamine inhalation on nonspecific airway hyperresponsiveness to histamine in patients with bronchial asthma]

The study was performed in 19 patients with stable mild/moderate asthma aged from 16 to 66. Nonspecific airway hyperresponsiveness (AH) to histamine was measured according to Cockcroft's et al. method and expresses as PC20H in mg/ml. The study was controlled by inhalation of PBS. The histamine or PBS challenges were performed three times at 45 min. intervals on the third day in case when the stability of AH on two preceding days was observed. The geometric means of PC20H (xg PC20H) during the consecutive three days did not change. They were 0.97, 0.92, 0.87 mg/ml (p > 0.05) respectively. Three times histamine challenges performed on the same day induced the decrease of AH (xg PC20H increased from 1.48 to 6.55 mg/ml) in 5 patients. In 4 other subjects the increase of AH was observed (xg PC20H decreased from 1.14 to 0.20 mg/ml). In 10 subjects the three times histamine challenges performed on the same day had no influence on AH to histamine.

Specificity of different organic nitrates to elicit NO formation in rabbit vascular tissues and organs in vivo

1. In the present study we assessed the formation of nitric oxide (NO) from classical and thiol-containing organic nitrates in vascular tissues and organs of anaesthetized rabbits, and established a relationship between the relaxant response elicited by nitroglycerin (NTG) and NO formation in the rabbit isolated aorta. Furthermore, the effect of isolated cytochrome P450 on NO formation from organic nitrates was investigated. 2. Rabbits received diethyldithiocarbamate (DETC; 200 mg kg-1 initial bolus i.p. and 200 mg kg-1 during 20 min, i.v.) and either saline, or one of the following organic nitrates: nitroglycerin (NTG, 0.5 mg kg-1), isosorbide dinitrate (ISDN), N-(3-nitratopivaloyl)-L-cysteine ethylester (SPM 3672), S-carboxyethyl-N-(3-nitratopivaloyl)-L-cysteine ethylester (SPM 5185), at 10 mg kg-1 each. After 20 min the animals were killed, blood vessels and organs were removed, and subsequently analyzed for spin-trapped NO by cryogenic electron spin resonance (e.s.r.) spectroscopy. 3. In the saline-treated control group, NO remained below the detection limit in all vessels and organs. In contrast, all of the nitrates tested elicited measurable NO formation, which was higher in organs (liver, kidney, heart, lung, spleen) (up to 4.8 nmol g-1 20 min-1) than in blood vessels (vena cava, mesenteric bed, femoral artery, aorta) (up to 0.7 nmol g-1 20 min-1). Classical organic nitrates (NTG, ISDN) formed NO preferentially in the mesenteric bed and the vena cava, while the SPM compounds elicited comparable NO formation in veins and arteries. 4. Using a similar spin trapping technique, NO formation was assessed in vitro in phenylephrine-precontracted rabbit aortic rings. The maximal relaxation elicited by a first exposure (10 min) to NTG (0.3 to 10 microM) was positively correlated (r = 0.8) with the net increase (NTG minus basal) of NO spin-trapped during a second exposure to the same concentration of NTG in the presence of DETC. 5. Cytochrome P450 purified from rabbit liver enhanced NO formation in a NADPH-dependent fashion from NTG, but not from the other nitrates, as assessed by activation of purified soluble guanylyl cyclase. 6. We conclude that the vessel selective action of different organic nitrates in vivo reflects differences in vascular NO formation. Thus, efficient preload reduction by classical organic nitrates can be accounted for by higher NO formation in venous capacitance as compared to arterial conductance and resistance vessels. In contrast, NO is released from cysteine-containing nitrates (SPMs) to a similar extent in arteries and veins, presumably independently of an organic nitrate-specific biotransformation. Limited tissue bioavailability of NTG and ISDN might account for low NO formation in the aorta, while true differences in biotransformation seem to account for differences in NO formation in the other vascular tissues.

Pyrrolidine dithiocarbamate selectively prevents the expression of the inducible nitric oxide synthase in the rat aorta

Exposure of rat aortic rings without endothelium to interleukin-1 beta for 5 h significantly attenuated the contractions due to phenylephrine and increased the tissue content of guanosine 3',5'-cyclic monophosphate (cyclic GMP) due to the induction of nitric oxide synthase. The presence of pyrrolidine dithiocarbamate, a specific inhibitor of nuclear transcription factor kappa B activation, during the exposure of the rings to interleukin-1 beta prevented these responses to interleukin-1 beta. Rat aortic rings which had been incubated for 5 h with interleukin-1 beta in the absence and presence of pyrrolidine dithiocarbamate prior to the organ chamber experiment had a similar concentration-dependent relaxation curve for acetylcholine in rings with endothelium, and for 3-morpholino-sydnonimine (SIN-1) in rings without. Pyrrolidine dithiocarbamate applied acutely did not alter the tone elicited by phenylephrine in rings with or without endothelium and had no effect on the subsequent relaxation induced by acetylcholine in rings with endothelium or by SIN-1 in rings without endothelium. These observations suggest that pyrrolidine dithiocarbamate prevents the interleukin-1 beta-mediated expression of the inducible nitric oxide synthase without affecting the activity of the constitutive enzyme in the rat aorta.

Contractility of the tail artery in rats treated with bezafibrate and fed atherogenic diet

Bezafibrate, a potent hypolipidemic agent, was studied as potentially preventive in the atherosclerosis-associated vascular hyperresponsiveness to alpha-adrenoceptors agonists in rats. Contractile responses to norepinephrine (NE) were determined in isolated tail arteries of rats fed an atherogenic or a standard diet. Atherogenic diet was biochemically confirmed to induce hypercholesterolemia. Used for 1 month, atherogenic diet increased pressor responses to NE in physiologic salt solution (PSS) and Ca(2+)-free PSS. When bezafibrate (100 mg/kg orally, p.o.) was administered simultaneously with atherogenic diet for 1 month, the effect was inhibited, but bezafibrate administered from day 15 of our experiment had no effect on vasoconstrictor responses to NE. Bezafibrate prevented changes in contractile responses of rat tail artery in the early stages of atherogenesis.

Antitumor organometallics. II. Inhibitory effects of two diphenyl-antimony (III) dithiophosphorus derivatives on in vitro and in vivo Ehrlich ascites tumor

(Diphenylphosphinodithioato) diphenylantimony (III), Ph2SbS2PPh2 (1) and (diisopropylphosphorodithioato) diphenylantimony(III), Ph2SbS2P(OPri)2 (2) were tested in vivo in male AKR mice and in vitro against Ehrlich ascites tumor cells. Both compounds exhibited dose-dependent inhibitory effects on in vivo tumor growth and on in vitro cell proliferation, cell viability, respiration and protein synthesis. The activities of some enzymes involved in energetic metabolism (Ca-ATPase, LDH, G6Pase) were exacerbated in vitro. The inhibitory effects could be related to the imbalance between ATP-producing and ATP-consuming processes in Ehrlich ascites tumor cells and also to their cell-cycle specificities.

Antitumor organometallics. I. Activity of some diphenyltin(IV) and diphenylantimony(III) derivatives on in vitro and in vivo Ehrlich ascites tumor

Diphenyltin(IV) and diphenylantimony(III) derivatives of dithiophosphorus ligands, i.e. Ph2Sn(S2PPh2)2 (1), Ph2Sn[S2P(OPr)2]2 (2), Ph2SbS2PPh2 (3) and Ph2SbS2P(OPri)2 (4), have been tested in vitro and in vivo against Ehrlich ascites tumor. All four compounds were almost equally effective in vitro, exhibiting inhibitory effects on cell proliferation, viability and protein synthesis, and exacerbated respiration and Ca-ATPase activity. In mice bearing Ehrlich ascites tumor cells, all four compounds inhibited the tumor growth, the organometallic phosphorodithioates being more active than phosphinodithioate analogues, and the organoantimony derivatives more active than organotins. Compound 4 (5 mg/kg/day, i.p., on days 1,3 and 5) produced an increase in life span of 83% and a cure rate of 30% in mice bearing this tumor.

The first organoantimony(III) compounds possessing antitumor properties: diphenylantimony(III) derivatives of dithiophosphorus ligands

Two organoantimony (III) derivatives, i.e., diphenylantimony diphenyl-dithiophosphinate, Ph2SbS2PPh2, and diphenylantimony diizopropyldithiophosphate, Ph2SbS2P(OPri)2, were shown to exhibit antitumor properties. Both compounds produced strong tumor inhibition effects in mice bearing Ehrlich ascites tumor. Moreover, the dithiophosphate (15 mg/kg, i.p., in days 1, 3 and 5) produced a cure rate of 30%.

Release from the Crabtree effect by hypoxic cell radiosensitizers

The Crabtree effect can be observed when the O2 consumption of tumour cells or of mammalian cells grown in culture is measured in physiological medium containing glucose. The effect of 2 hypoxic cell radiosensitizers, misonidazole and NDPP, on the O2 consumption of Ehrlich ascites tumour cells was compared in media with and without glucose. A stimulatory effect on O2 consumption was found for 5--20mM misonidazole as well as for 0.5mM NDPP, both in media containing 10(-2)M glucose. Thus glucose induced a Crabtree effect in Ehrlich tumour cells, expressed as 38--45% inhibition of O2 consumption relative to that in the same medium without glucose. The stimulatory effect of misonidazole and NDPP on O2 utilization in medium with glucose undoubtedly appeared as a release from the Crabtree effect.

Effect of anoxic radiosensitizers on cellular and mitochondrial oxygen consumption and respiration control ratio

Misonidazole increased oxygen consumption of Ehrlich ascites cells and reversed the blockage of oxidative phosphorylation induced by amytal and KCN. It alos increased oxygen consumption of mitochondria in the presence of alpha-ketoglutarate substrate, but decreased the respiratory control ratio. Cellular oxygen consumption decreased, but mitochondrial consumption was increased by metronidazole, and the respiratory control ratio was not affected by this substance. It was concluded that misonidazole influences respiration in a similar way to uncouplers, and the interaction site for both substances is at the NADH level. These respiratory effects can be of importance in altering radiation response in multicellular tissues.