Susceptibility to prosocial and antisocial influence in adolescence.

INTRODUCTION: Adolescents are particularly susceptible to social influence and previous studies have shown that this susceptibility decreases with age. The current study used a cross-sectional experimental paradigm to investigate the effect of age and puberty on susceptibility to both prosocial and antisocial influence. METHODS: Participants (N = 520) aged 11-18 from London and Cambridge (United Kingdom) rated how likely they would be to engage in a prosocial (e.g. "help a classmate with their work") or antisocial (e.g. "make fun of a classmate") act. They were then shown the average rating (in fact fictitious) that other adolescents had given to the same question, and were then asked to rate the same behaviour again. RESULTS: Both prosocial and antisocial influence decreased linearly with age, with younger adolescents being more socially influenced when other adolescents' ratings were more prosocial and less antisocial than their own initial rating. Both antisocial and prosocial influence significantly decreased across puberty for boys but not girls (independent of age). CONCLUSIONS: These findings suggest that social influence declines with increasing maturity across adolescence. However, the exact relationship between social influence and maturity is dependent on the nature of the social influence and gender. Understanding when adolescents are most susceptible to different types of social influence, and how this might influence their social behaviour, has important implications for understanding adolescent social development.

The impact of mindfulness training in early adolescence on affective executive control, and on later mental health during the COVID-19 pandemic: a randomised controlled trial.

BACKGROUND: Previous research suggests that mindfulness training (MT) appears effective at improving mental health in young people. MT is proposed to work through improving executive control in affectively laden contexts. However, it is unclear whether MT improves such control in young people. MT appears to mitigate mental health difficulties during periods of stress, but any mitigating effects against COVID-related difficulties remain unexamined. OBJECTIVE: To evaluate whether MT (intervention) versus psychoeducation (Psy-Ed; control), implemented in after-school classes: (1) Improves affective executive control; and/or (2) Mitigates negative mental health impacts from the COVID-19 pandemic. METHODS: A parallel randomised controlled trial (RCT) was conducted (Registration: https://osf.io/d6y9q/; Funding: Wellcome (WT104908/Z/14/Z, WT107496/Z/15/Z)). 460 students aged 11-16 years were recruited and randomised 1:1 to either MT (N=235) or Psy-Ed (N=225) and assessed preintervention and postintervention on experimental tasks and self-report inventories of affective executive control. The RCT was then extended to evaluate protective functions of MT on mental health assessed after the first UK COVID-19 lockdown. FINDINGS: Results provided no evidence that the version of MT used here improved affective executive control after training or mitigated negative consequences on mental health of the COVID-19 pandemic relative to Psy-Ed. No adverse events were reported. CONCLUSIONS: There is no evidence that MT improves affective control or downstream mental health of young people during stressful periods. CLINICAL IMPLICATIONS: We need to identify interventions that can enhance affective control and thereby young people's mental health.

Regulation of microtubule assembly in cultured fibroblasts.

Microtubule assembly in diploid human skin fibroblasts was studied by [3H]colchicine binding to disaggregated microtubule subunits and to total cell tubulin. Microtubule content per milligram of cell protein was critically dependent upon cell density. As cultures neared confluence, microtubules increased and total cell tubulin decreased; the percent of tubulin assembled into microtubules increased from 5.3 in spare cultures to 58.3 in confluent cultures. Microtubules disappeared with a half-time of 2 min in response to 0 degree C incubation and reformed upon rewarming. Brief treatment of intact cells with concanavalin A or cytochalasin A depolymerized microtubules to 55 or 56% of control levels. The effect of concanavalin A was prevented by alpha-methylmannoside. Fibroblast microtubule assembly was not significantly altered by cyclic nucleotides, ascorbate, glucose, insulin, medium calcium concentration, or calcium ionophore A23187.

Myosins of secretory tissues.

Myosin has been purified from the principal pancreatic islet of catfish, hog salivary gland, and hog pituitary. Use of the protease inhibitor Trasylol (FBA Pharmaceuticals, New York) was essential in the isolation of pituitary myosin. Secretory tissue myosins were very similar to smooth muscle myosin, having a heavy chain of 200,000 daltons and light chains of 14,000 and 19,000 daltons. Salivary gland myosin cross-reacted with antibodies directed toward both smooth muscle myosin and fibroblast myosin, but not with antiskeletal muscel myosin serum. The specific myosin ATPase activity measured in 0.6 M KCl was present. Tissues associated with secretion of hormone granules contained substantial amounts of this ATPase, rat pancreatic islets having 4.5 times that of rat liver. Activation of low ionic strength myosin ATPase by actin could not be demonstrated despite adequate binding of the myosin to muscle actin and elution by MgATP. The myosins were located primarily in the cytoplasm as determined by cell fractionation and were quite soluble in buffers of low ionic strength.

Muscle actin filaments bind pituitary secretory granules in vitro.

Hog anterior pituitary secretory granules sediment at 3,000 g. When rat or rabbit skeletal muscle actin filaments are present with the granules, the sedimentation decreases markedly. Depolymerized actin or viscous solutions of Ficoll and collagen have no effect on granule sedimentation. With this assay, actin filaments bind secretory granules (consisting of the proteinaceous core plus limiting membrane), secretory granule membranes, mitochondria, artificial lecithin liposomes, and styrene-butadiene microspheres, but have little or no interaction with membrane-free secretory granule cores and albumin microspheres. A secretory granule-actin complex sedimentable between 3,000 g and 25,000 g can be isolated. Metal ions, nucleotides, salts, dithiothreitol, or pretreatment of the granules with trypsin do not destroy the binding, which appears to be a lipophilic interaction.

Acute stimulated hormone release from cultured GH3 pituitary cells.

Treatment of cultured rat pituitary GH3 cells with 50 mM KCl in growth medium released 33% of cell PRL and 18% of cell GH with a half-time of 5 min. Hormone in the culture medium was increased 2- to 4-fold over unstimulated levels. The response required calcium; barium and strontium, but not magnesium, could substitute for calcium. Low temperature completely inhibited hormone release, which was also reduced significantly by inhibitors of energy metabolism and by nitrogen. This acute response was similar in ionic requirements, hormones released, and time course to the acute effect of TRH. Like potassium stimulation, TRH resulted in acute release of both PRL and GH. This contrasts with the finding that chronic TRH treatment reduced GH synthesis in GH3 cells. After a 10-min preincubation with potassium, subsequent short incubations with potassium released little hormone unless the cells were allowed to recover by incubation in normal medium for at least 2 h. This acutely releasable hormone pool seems to be located in a membrane-bound subcellular fraction, since GH3 cells did not discharge the cytoplasmic marker enzyme, lactate dehydrogenase, during potassium-stimulated hormone release.

The role of radiotherapy in thymomas.

Thymoma is a rare disorder and the treatment of invasive disease is controversial. Seventeen patients with pathologically confirmed thymoma were treated at Royal Prince Alfred Hospital between 1982 and 1993. There were two stage 1 patients, four stage 2 patients and 11 stage 3 patients. Five patients had total resection, eight patients had subtotal resection and four patients had biopsy only. All patients received radiotherapy, with the median dose being 50 Gy. The median survival was 117 months and the 5-year survival was 69%. This was influenced by stage of disease and extent of surgical resection. The local control was 76%. Three patients developed distant metastatic disease. There were insufficient numbers to determine a dose response to radiotherapy. Patients with invasive disease should continue to have postoperative radiotherapy. A brief review of the literature is made.

Extensive basal cell carcinoma treated with the mould radiotherapy technique.

Superficial extensive basal cell carcinoma of the head and neck region can be difficult to treat because of the large area of skin involved, and the changing contour of the head and neck region. A patient with basal cell carcinoma involving the upper chest and neck treated with mould radiotherapy is presented.

Brachytherapy in oesophageal carcinoma.

Patients with recurrent or locally advanced oesophageal carcinoma have a poor prognosis. Relief of dysphagia is often the goal of any further treatment. Several methods, including laser re-canalization, prosthetic intubation, dilatation, external beam irradiation (EBI) and intraluminal brachytherapy (IBT) can be used to alleviate dysphagia. In this retrospective review of 11 patients, eight with recurrent tumour and three newly diagnosed patients were treated with low dose rate IBT. Relief of dysphagia was achieved in nine patients, all of whom were able to maintain swallowing of at least a semi-solid diet until death or last follow-up. Toxicity was minimal, but survival was poor, with a median survival of only 3 months. IBT presents several advantages over other palliative methods, especially in recurrent tumours where re-treatment with EBI is often difficult because of normal tissue tolerance. Low dose rate IBT takes only 1-2 days to deliver, is highly effective, has little morbidity and the palliation achieved is relatively durable.

Splenic irradiation in HIV-related thrombocytopenia.

Splenic irradiation has been used in patients with HIV-related thrombocytopenia. This retrospective review deals with four patients treated with low dose splenic irradiation. All patients had an increase in platelet count and tolerated the treatment without side effects. However, the treatment response lasted for several months only.

Progression of myopia in Hong Kong Chinese schoolchildren is slowed by wearing progressive lenses.

PURPOSE: In Chinese societies, primary and secondary schoolchildren perform large amounts of reading and homework and thus spend long periods performing near work during their growth years. Progressive lenses, which can permit a focused retinal image at distance, intermediate, and near, without accommodation, may slow the development of myopia. This paper reports results of a 2-year longitudinal study to examine the effects of progressive lenses on myopia progression in myopic Chinese children; these children were aged between 9 and 12 years at the beginning of the study. METHODS: Prestudy vision screening tests and five examinations, which included noncycloplegic refraction, were conducted at half-yearly intervals. Of those who completed the study, 32 children wore single vision (SV) lenses (the SV group) and 36 wore progressive lenses; of the latter, 22 wore a +1.50 D addition (the P1 group) and 14 wore a +2.00 D addition (the P2 group). Refractive error, corneal curvature, axial length, vitreous depth, and intraocular pressure were measured at every examination. Height was measured as an index of general growth. RESULTS: Progressive lenses significantly retarded the progression of the myopia in these children. Initially, the mean refractive error of the SV group was -3.67 D, of the P1 group was -3.73 D, and of the P2 group was -3.67 D. The mean myopic progressions over the 2 years of the study were -1.23, -0.76, and -0.66 D for the SV, P1, and P2 groups, respectively. CONCLUSION: Progressive lenses reduce the progression of myopia. It may be that the interaction of the progressive lenses with the accommodation system is the cause of this reduction in myopia progression because the +2.00 D addition appeared more effective than the +1.50 D addition in slowing the progression.

Intraluminal brachytherapy in the treatment of bile duct carcinomas.

Patients with carcinoma of the biliary tract have a poor prognosis because the disease is often unresectable at diagnosis. Intraluminal brachytherapy has been reported as an effective treatment for localized cholangiocarcinoma of the biliary tract. The purpose of our study was to analyse the survival of patients treated with brachytherapy and make some recommendations regarding its use. Fifteen patients underwent brachytherapy via a trans-hepatic approach at the Royal Prince Alfred Hospital from 1983 to 1993. Eleven patients had low-dose rate brachytherapy and four patients had high-dose rate treatment. There were nine males and six females. The median age was 64 years. Other treatment included bypass procedures in two patients, endoscopic stents in 14 patients and external beam irradiation in one patient. The median survival was 12.5 months and 47% of the patients survived 1 year. The only complication reported was cholangitis which was seen in one patient. There did not seem to be any difference in survival or complications between low- and high-dose rate brachytherapy. We conclude that the addition of intraluminal brachytherapy after biliary drainage prolongs survival and is a safe and effective treatment, but patients still have a high rate of local failure, and further studies will be needed to address this problem.

Radiotherapy for Hodgkin's disease in pregnancy.

Hodgkin's disease diagnosed during pregnancy poses a dilemma as there are risks of abortion and fetal malformation with the use of radiotherapy and chemotherapy. A patient with Hodgkin's disease during pregnancy treated with radiotherapy is presented.

Binding of colchicine to purified microtubule protein.

The binding of colchicine to tubulin, purified by two cycles of assembly-disassembly, has been studied. Equilibrium studies indicated a dissociation constant which declined during incubation approaching a minimum value of approximately 0.30 times 10- minus 6 M after 13 hours of incubation. Because tubulin is unstable during prolonged incubation (t1/2 of 5.2 hours for free tubulin, t1/2 of 12.5 hours for tubulin bound to colchicine), the equilibrium Kd was felt to be an overestimation of the true Kd. The rate constant of dissociation (k-1 equal to 0.009 hour- minus 1 hour- minus 1) and the rate constant of association (k1 equal to 0.37 times 10-6 M-minus 1) were measured under conditions designed to circumvent or correct for tubulin instability. The dissociation constant determined by the ratio k-1/k1 was 0.024 times -minus 6 M. To determine whether the discrepancy between the "equilibrium" and "kinetic" determined dissociation constants could be accounted for on the basis of tubulin instability, the binding reaction was computer-simulated using the measured association and dissociation rate constants and the rate constants for decay of bound and free tubulin. Computer simulation was in close agreement with the experimentally determined behavior of the reaction during a 13-hour incubation. It is concluded that the Kd determined by equilibrium methodology results in a considerable overestimation due to the instability of tubulin, and that the best estimate for the Kd of the colchicine-tubulin equilibrium is the value determined by the ratio of the rate constants.

The cytoskeleton in Chediak-Higashi syndrome fibroblasts.

The Chediak-Higashi syndrome (CHS) trait is expressed in cultured human skin fibroblasts as an abnormal perinuclear concentration of moderately enlarged lysosomes. The cytoskeleton of CHS fibroblasts appears intact. Microtubules are normal in number and morphology, as assessed by colchicine binding studies, antitubulin immunofluorescence, and electron microscopy. Deformability by shear force is unaltered and microfilaments are abundant. However, CHS lysosomes appear to interact abnormally with the cytoskeleton, since the perinculear aggregation partially disperses after depolymerization of cell microtubules with colchicine. These results suggest that CHS is associated with a defect of either the lysosomal membrane itself or of lysosomal membrane-microtubule interaction.