Evidence that implementation intentions reduce self-harm in the community

Objectives

Implementation intentions are ‘IF-THEN’ plans that encourage goal-intended behaviour. This study was designed to test whether an intervention encouraging the formation of implementation intentions can reduce self-harm in the community.

Design

A randomized controlled design was used.

Methods

At pre-intervention, outcome variables (self-harm in both specified and unspecified critical situations and suicidality) and potential moderators of implementation intentions (goal intention, mental imagery, and exposure to self-harm) were measured using self-report questionnaires. The participants (N = 469, aged 18–66 years, 86.4% female, 6.8% male and 6.7% other) were then randomized to either an experimental (implementation intention) or control task. At three-months post-intervention, self-report questionnaires were used again to measure the outcome variables.

Results

There were no overall differences between the conditions at post-intervention. However, goal intention and mental imagery, but not exposure to self-harm, moderated the effects of condition on self-harm in specified critical situations. At high (mean + 1SD) levels of both goal intention and mental imagery, the experimental condition reported self-harming less frequently in the situations specified in their implementation intentions.

Conclusions

Implementation intentions therefore represent a useful intervention for reducing self-harm in specified critical situations for people in the community who wish to avoid self-harm and those who frequently experience self-harm and suicide related mental imagery.     

Clinically relevant suramin dosing regimen in mice with no effects against PC-3 prostate xenografts

The goal of these studies was to develop a suramin dosing schedule that would maintain suramin plasma concentrations in mice in the 150-250 mu g/ml range. A high pressure liquid chromatography method was used to determine suramin plasma concentrations in mice. For pharmacokinetic studies CD2F(1) mice were treated intraperitoneally with 140 mg/kg of suramin. These pharmacokinetic data were used to develop a clinically relevant dosing regimen. To test the efficacy of this dosing regimen, athymic nude mice were implanted orthotopically with PC-3 prostate carcinoma cells, randomized, and treated intraperitoneally. The pharmacokinetically derived dosing regimen resulted in no antitumor effect against PC-3 prostate tumors. Suramin plasma concentrations ranged from 155 to 258 mu g/ml over the 14-day therapy period with tumor concentrations in the 53-241 mu g/g wet weight range.     

Deciduous enamel defects in low-birth-weight children: correlated X-ray microtomographic and backscattered electron imaging study of hypoplasia and hypomineralization

Enamel does not remodel, and disturbances occurring during development may remain in the tooth as a permanent record of the upset. Mineralization in prenatal and postnatal deciduous enamel was studied in the shed deciduous incisors of low-birth-weight (LBW: < 2kg) children. The specific objective was to gain further insight into the mechanism of formation of developmental defects of enamel. Sections at a resolution of 22–40 m were reconstructed using X-ray microtomography (CT) giving absolute measurements of linear absorption coefficient for AgK radiation. Detail to ca. 1 m resolution was obtained using automated, digital backscattered electron (BSE) imaging of PMMA-embedded material. Matching the histograms of BSE and CT images made possible the calibration of the mean atomic number-dependent signal in the BSE images. The comparison of abnormal, affected enamel regions and post-recovery, normal, unaffected regions could be made in the same teeth, since these zones were easily recognized from the distribution of hypoplasia and hypomineralization. The CT values, converted to calculated mineral densities, ranged from 2.3 g cm^-3 to 2.6 g cm^-3 in LBW hypoplastic, and between 2.65 and 2.78 g cm^-3 in control primary enamel and post-defect, post-natal LBW enamel. Hypoplasia with or without minimal hypomineralization indicated recovery of the ameloblasts in the maturation phase. Disturbance during late matrix formation and early maturation resulted in hypoplasia and hypomineralization.     

Calcification of the human thoracic aorta during aging

The rate of calcification within the human thoracic aorta from completion of body growth to advanced old age was examined. Fifty-eight aortae, obtained at necropsy, were dissected into four layers: the complete intima and the separated media, which was subdivided into three tissue samples of equal thickness, defined as the media-inner,-middle, and-outer layers. The sampling sites selected for analysis were from regions of the aortic surface that were free of atherosclerotic plaques. The calcium content within each tissue layer of the aorta was determined. Arterial wall thickness and the cholesterol content of the four layers were also measured. Intimal calcification increased progressively during aging: from 1.6 g Ca/mg tissue at 20 years of age to 5.2 g Ca/mg tissue by 90 years of age. When intima calcium concentration was expressed by tissue volume (w/v), no significant change during aging was found. Medical calcification, as w/v and by w/w, increased throughout aging. Calcium accumulation was most marked in the middle, elastin-rich layer of the media, increasing from 1.4 g Ca/mg tissue at 20 years of age to 49.50 g Ca/mg tissue by 90 years of age. Calcium levels also increased in the other media layers, but at a slower rate then that found within the middle media.     

Binding of antidepressants to human brain receptors: focus on newer generation compounds

Using radioligand binding assays and postmortem normal human brain tissue, we obtained equilibrium dissociation constants (K_ds) for 17 antidepressants and two of their metabolites at histamine H₁, muscarinic, ₁-adrenergic, ₂-adrenergic, dopamine D₂, serotonin 5-HT_1A, and serotonin 5-HT₂ receptors. Several newer antidepressants were compared with older drugs. In addition, we studied some antimuscarinic, antiparkinson, antihistamine, and neuroleptic compounds at some of these receptors. For the antidepressants, classical tricyclic antidepressants were the most potent drugs at five of the seven receptors (all but ₂-adrenergic and 5-HT_1A receptors). The chlorophenylpiperazine derivative antidepressants (etoperidone, nefazodone, trazodone) were the most potent antidepressants at ₂-adrenergic and 5-HT_1A receptors. Of ten antihistamines tested, none was more potent than doxepin at histamine H₁ receptors. At muscarinic receptors antidepressants and antihistamines had a range of potencies, which were mostly weaker than those for antimuscarinics. From the in vitro data, we expect adinazolam, bupropion, fluoxetine, sertraline, tomoxetine, and venlafaxine not to block any of these five receptors in vivo. An antidepressant's potency for blocking a specific receptor is predictive of certain side effects and drug-drug interactions. These studies can provide guidelines for the clinician in the choice of antidepressant.     

Inhibition of the epidermal growth factor receptor tyrosine kinase by PD153035 in human A431 tumors in athymic nude mice

Summary PD153035 is a potent (K_i=6 pm) and specific inhibitor of the epidermal growth factor (EOF) receptor tyrosine kinase that suppresses tyrosine phosphorylation of the EGF receptor in A431 cells at nanomolar concentrations in cell culture. We have examined the pharmacokinetics of this compound and its ability to rapidly suppress phosphorylation of the EGF receptor in A431 human epidermoid tumors grown as xenografts in immunodeficient nude mice. Following a single i.p. dose of 80 mg/kg, the drug levels in the plasma and tumor rose to 50 and 22 M within 15 minutes. While the plasma levels of PD153035 fell below 1 M by 3 hours, in the tumors it remained at micromolar concentrations for at least 12 hours. The tyrosine phosphorylation of the EGF receptor was rapidly suppressed by 80–90% in the tumors. However receptor phosphorylation returned to control levels after 3 hours despite the continued presence of the drug at concentrations which, based on previousin vitro results, were predicted to maintain inhibition. EGF-stimulated tyrosine kinase activity in tumor extracts was decreased and recovered in parallel with the effects of PD153035 on receptor phosphorylation though the activity had reached only about half of the control activity after three hours. These results demonstrate the potential for using small molecule inhibitors to inhibit the EGF receptor tyrosine kinasein vivo, though a fair evaluation of their potential anti-cancer activity will have to wait for solutions to problems with sustained delivery which may allow us to maintain suppression of EGF receptor phosphorylation.     

Measures to prevent cricket injuries: an overview

Cricket is a major international sport, generally played in British Common-wealth nations. Although strictly a non-contact sport, injuries in cricket can result in a number of ways. In high level cricket, overuse injuries are common and related to the physical demands of the sport, particularly in the delivery of the ball. The bowling action involves repetitive twisting, extension and rotation of the trunk at the same time as absorption of large ground reaction forces over a short period of time. These movements, if performed incorrectly or too frequently, can lead to overuse injuries of the back, particularly in elite and high level cricketers. Cross-sectional studies have demonstrated that spinal overuse injuries occur more frequently to cricketers adopting a mixed bowling action than to those who favour a front- or side-on bowling technique. Strategies to ensure that cricketers do not adopt the mixed action or bowl too fast for extended periods can prevent these back injuries. Injuries resulting from impacts, generally from the cricket ball, can also occur and are more common during low level competition or informal participation. Because of the potential severity of these impacts, a range of protective equipment ranging from body padding to gloves and face protectors are now common features of standard cricket equipment. Although a number of measures to prevent cricket injuries have been widely suggested in the literature, there have been very few studies that have formally assessed their effectiveness in preventing injury. Further research is needed to gain a greater understanding of the biomechanics of cricket actions, the mechanisms of resultant injuries and the role of various risk factors in injury causation.