The impact of 3,4-methylendioxymetamphetamine (MDMA) abstinence on seeking behavior and the expression of the D2-like and mGlu5 receptors in the rat brain using saturation binding analyses

The abundance of research indicates that enriched environment acts as a beneficial factor reducing the risks of relapse in substance use disorder. There is also strong evidence showing the engagement of brain dopaminergic and glutamatergic signaling through the dopamine D₂-like and metabotropic glutamate type 5 (mGlu₅) receptors, respectively, that has a direct impact on drug reward and drug abstinence. The present study involved 3,4-methylendioxymethamphetamine (MDMA) self-administration with the yoked-triad procedure in rats kept under different housing conditions during abstinence - enriched environment (EE) or isolation cage (IC) conditions - aimed at evaluating changes in brain receptors affecting drug-seeking behavior as well as density and affinity of the D₂-like and mGlu₅ receptors in several regions of the animal brain. Our results show that exposure to EE conditions strongly reduced active lever presses during cue-induced drug-seeking. At the neurochemical level, we demonstrated marked decreases of D₂-like receptor affinity in the dorsal striatum in rats previously self-administering MDMA under EE and increases in density under IC conditions. Moreover, we found the increases in the density and decreases in the affinity of the D₂-like receptor in the prefrontal cortex and nucleus accumbens provoked by IC conditions. The mGlu₅ receptor density decreased only in the prefrontal cortex after IC and EE abstinence. Moreover, our study has revealed a clear decrease in mGlu₅ receptor density in the nucleus accumbens in the group actively administering MDMA only under EE conditions. This study demonstrates that housing conditions have impact on drug-seeking behavior in rats during abstinence from MDMA self-administration. The observed changes in the dopamine D₂-like and mGlu₅ receptor B_max and/or K_d values were brain-region specific and related to either pharmacological and/or motivational features of MDMA.

Pelvic movements during walking throughout gestation - the relationship between morphology and kinematic parameters

BACKGROUND

Many researchers emphasize adaptations following pregnancy. Our purpose was to get more insight into how morphology interacts with the pelvic walking pattern - the segment most prone to the adaptation following altered body demands.

METHODS

Thirty women were enrolled. Three experimental sessions were arranged according to the same protocol in the first, second and third trimesters of pregnancy. First, the anthropometric measures were taken, then walking trials at a self-selected speed were registered. At the end of the experimental session the subjects were asked to fill out a questionnaire on pain.

FINDINGS

The sagittal plane pelvic range of motion (RoM) significantly increased throughout pregnancy. There were significant positive correlations between pelvic anthropometric dimensions and pelvic tilt and rotation primarily in the third trimester of pregnancy. Significant positive correlations were found between pelvic RoM and thigh circumference. Indicators associated with body mass increase were positively correlated with pelvic obliquity in the second trimester and pelvic tilt and rotation in late pregnancy. It is also worth noting that the individual differences were not related to back pain and that the reported correlations were observed in some but not in all trimesters.

INTERPRETATION

Morphological changes following the fetus growth induced increased pelvic tilt and rotation, however, pelvis movements were not associated with back pain. Overall, the results highlight correlations between morphology and pelvis kinematic patterns in some but not in all trimesters.

Progressive changes in walking kinematics throughout pregnancy-A follow up study

BACKGROUND

Progressive weight gain and changes in its distribution following pregnancy may be challenging for the gravidas' ability to move in a stable way.

RESEARCH QUESTION

How is gait kinematics changing throughout pregnancy and to what extend is it affected by physical activity level and energy balance?

METHODS

30 women were enrolled. Three experimental sessions were arranged according to the same protocol in the first, second and third trimesters of pregnancy. Walking kinematics at a self-selected speed was registered. The total physical activity (TPA) was assessed from the subjects' questionnaires. Energy balance ('positive', 'balanced' or 'negative') was estimated as the difference between dietary energy intake and energy expenditure during 7 days.

RESULTS

No significant differences were found in the spatiotemporal variables between experimental sessions. However, the gait analysis revealed significant increments in the single support and base of support (BoS) measures. Generally, the sagittal plane mobility of the lower limb joints did not differ, however, the pelvic tilt increased in late pregnancy. The hip and pelvis angles were significantly different over the gait cycle throughout gestation. The 'balanced' energy was dominant in the first trimester although the relative number of participants with negative balance increased over pregnancy. Overall, gait parameters were independent of the energy balance. However, significant correlation was found between gait parameters, such as BoS, velocity, stride length, and TPA in the advanced pregnancy.

SIGNIFICANCE

The longitudinal assessment of walking kinematics demonstrates few changes adopted to accommodate for pregnancy. The enlargement of BoS is considered as a strategy to provide safety and stability. The increased pelvic tilt is likely to compensate for changes in the body mass distribution. The physical activity correlates with the BoS measures and stride length and thus may be important for enhancing gait stability.

Physiological and environmental factors associated with central fat distribution in pubertal girls

The aim of the work was to determine a degree of explanation of the variation of central fat distribution described by the waist-to-height ratio (WHtR) and waist circumference (WC) by both environmental and biological factors, including hormonal ones. The authors also intended to define the factors which are connected with a risk of abdominal obesity in girls. The study material includes a cross-sectional sample of 297 girls aged 9–16 years, examined in sport and regular schools in Cracow, Poland. Direct anthropometric measurements were done, breast development was assessed (Tanner stage) and leptin and ghrelin concentration in blood serum was estimated (by RIA method). The girls’ lifestyles and socio-economic status were investigated through survey questionnaires. The stepwise descending regression method was applied to evaluate a degree of WC, WHtR and BMI variation explanation. A logistic regression analysis was conducted to indicate factors connected with a risk of abdominal obesity (WHtR ³ 0.50) by calculating odds ratio (OR) and 95% confidence interval (CI). Variation of WC and WHtR was explained in, respectively, 53% and 44% by biological factors i.e. age, body height, the Tanner stage and blood serum leptin and ghrelin concentration as well as by environmental factors i.e. obesity prevalence in fathers and the girls’ high physical activity. Variation of BMI was explained in 56% by a similar set of variables, excluding the level of physical activity. The biological factors were the highest determinants of an adipose tissue distribution type in the girls. Besides biological factors a significant role was also played by the environmental ones: obesity prevalence in fathers and high level of physical activity. The waist to height ratio seemed to be a more sensitive identifier of environmental behaviours than the general adiposity index.

Phase 1 dose-escalation study of S-222611, an oral reversible dual tyrosine kinase inhibitor of EGFR and HER2, in patients with solid tumours

BACKGROUND

S-222611 is a reversible inhibitor of EGFR, HER2 and HER4 with preclinical activity in models expressing these proteins. We have performed a Phase 1 study to determine safety, maximum tolerated dose (MTD), pharmacokinetic profile (PK) and efficacy in patients with solid tumours expressing EGFR or HER2.

PATIENTS AND METHODS

Subjects had advanced tumours not suitable for standard treatment, expressing EGFR or HER2, and/or with amplified HER2. Daily oral doses of S-222611 were escalated from 100mg to 1600 mg. Full plasma concentration profiles for drug and metabolites were obtained.

RESULTS

33 patients received S-222611. It was well tolerated, and the most common toxicities, almost all mild (grade 1 or 2), were diarrhoea, fatigue, rash and nausea. Only two dose-limiting toxicities occurred (diarrhoea and rash), which resolved on interruption. MTD was not reached. Plasma exposure increased with dose up to 800 mg, exceeding levels eliciting pre-clinical responses. The plasma terminal half-life was more than 24h, supporting once daily dosing. Responses were seen over a wide range of doses in oesophageal, breast and renal tumours, including a complete clinical response in a patient with HER2-positive breast carcinoma previously treated with lapatinib and trastuzumab. Four patients have remained on treatment for more than 12 months. Downregulation of pHER3 was seen in paired tumour biopsies from a responding patient.

CONCLUSIONS

Continuous daily oral S-222611 is well tolerated, modulates oncogenic signalling, and has significant antitumour activity. The recommended Phase 2 dose, based on PK and efficacy, is 800 mg/day.

Association of the physical activity with leptin blood serum level, body mass indices and obesity in schoolgirls

Decreased physical activity is undoubtedly significantly associated with obesity. Similarly, the proper hormones secretion, the proper weight and body development. The aim of this study was to investigate the relationship between body mass composition and leptin concentration in relation to the degree of physical activity expressed in MET-h/week (metabolic equivalent per week). The study included 59 girls, aged 9-16 years (12.55±1.67) and divided into two groups: 1) PA: a physically active group of 29 girls and 2) PI: a group of 30 physically inactive girls. In all, physical activity was assessed using modified questionnaire concerning "activity for adolescents" and expressed in MET-h/week. Serum blood leptin concentrations in fasting girls were determined by RIA. Anthropometric parameters were measured and fatness indices calculated (BMI, SF, WHtR). Body composition (%BF, FM, FFM) was assessed using bioelectrical impedance analysis method (BIA). Statistical analysis showed significant differences between groups of PA and PI concerning values of BMI, WHtR, %BF, WC and MET-h/week as well as in leptin concentrations. In both groups of girls negative correlations between physical activity measured in MET and leptin concentrations and in WHtR were observed. The concentration of leptin was directly proportional to the degree of body fat and to the body composition expressed by BMI, WHtR, log SF, WC and %BF, FM and FFM, respectively. Increased physical activity was associated with lower body fat ratios and WHtR, BMI, WC, %BF, but did not affect significantly the changes in the values of log SF, FM and FFM. Higher values of BMI, WHtR and WC can provide not only a greater risk of obesity in general, but also cause excessive accumulation of fat in the central part of the body (abdominal obesity).

Dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma: meta-analysis

OBJECTIVE

To examine the dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma.

DESIGN

Meta-analysis of placebo controlled, randomised clinical trials that presented data on at least one outcome measure of asthma and that used at least two different doses of fluticasone.

SETTING

Medline, Embase, and GlaxoWellcome's internal clinical study registers.

MAIN OUTCOME MEASURES

FEV(1), morning and evening peak expiratory flow, night awakenings, beta agonist use, and major exacerbations.

RESULTS

Eight studies, with 2324 adolescents and adults with asthma, met the inclusion criteria. Data on doses of >500 microg/day were limited. The dose-response curve for the raw data began to reach a plateau at around 100-200 microg/day and peaked by 500 microg/day. A negative exponential model for the data, without meta-analysis, indicated that 80% of the benefit at 1000 microg/day was achieved at doses of 70-170 microg/day and 90% by 100-250 microg/day. A quadratic meta-regression showed that the maximum achievable efficacy was obtained by doses of around 500 microg/day. The odds ratio for patients remaining in a study at a dose of 200 microg/day, compared with higher doses, was 0.73 (95% confidence interval 0.49 to 1.08). Comparison of the standardised difference in FEV(1 )for an inhaled dose of 200 microg/day against higher doses showed a difference in FEV(1) of 0.13 of a standard deviation (-0.02 to 0.29).

CONCLUSIONS

In adolescent and adult patients with asthma, most of the therapeutic benefit of inhaled fluticasone is achieved with a total daily dose of 100-250 microg, and the maximum effect is achieved with a dose of around 500 microg/day. However, these findings were limited by the lack of data on individual patients and by the paucity of dose-response studies that included doses of >500 microg/day.

The accuracy of references in Australian and New Zealand Medical Journals

AIMS

Previous studies have found high error rates in references in biomedical journals. The aim of this paper was to assess the accuracy of references in three Australian and New Zealand general medical journals.

METHODS

References from the August 1999 issues of the Medical Journal of Australia, the New Zealand Medical Journal and the Australian and New Zealand Journal of Medicine were assessed for accuracy using PubMed of the National Library of Medicine.

RESULTS

This study found a high rate of reference errors in Australian and New Zealand medical journals. The reference error rate ranged from 33.5 to 48.8%. The most frequent errors were in the author's names and in the title.

CONCLUSIONS

The reference error rate in Australia and New Zealand medical journals is high and is preventable. Authors should be more diligent and preferably verify cited references against the original article.