Methylphenidate effects in attention deficit/hyperactivity disorder: electrodermal and ERP measures during a continuous performance task

Rationale Previous research investigating the effects of stimulants, such as methylphenidate (MPH), on children with attention deficit/hyperactivity disorder (AD/HD) has rarely included autonomic measures of arousal.Objective Our aim was to clarify the effects of MPH on central and autonomic measures in AD/HD children during a continuous performance task (CPT) using a naturalistic open-label study.Method Thirty-six boys (18 AD/HD and 18 control) participated in a CPT over two trial periods, allowing a more valid estimate of the effects of medication, rather than assuming that retesting per se has no substantial impact. MPH was administered to the AD/HD group 1 h prior to the second trial. Errors and reaction time (RT) were recorded as measures of performance, electrodermal activity as an autonomic nervous system measure and event-related potentials (ERPs) as an index of central nervous system activity.Results AD/HD children made more errors than controls in the first session, but no group differences were found after medication. No significant differences were observed for RT. Skin conductance level was found to be lower in AD/HD children than controls, but this difference was also ameliorated after medication. Conversely, mean skin conductance response to target stimuli was found not to differ between groups during the initial test phase but became significantly different in phase 2. ERP data showed topographic differences between groups in N1, P2, N2 and P3 at the initial test phase, which were reduced at the second test.Conclusion Stimulant medication ameliorated some of the dysfunctions in AD/HD children, which are reflected in behavioural and ERP measures. These results, in combination with general differences in electrodermal activity, support a hypoarousal model of AD/HD, which can explain the action of MPH in these children.     

Factors influencing variation in basal metabolic rate include fat-free mass, fat mass, age, and circulating thyroxine but not sex, circulating leptin, or triiodothyronine

BACKGROUND: Basal metabolic rate (BMR) is the largest component of daily energy demand in Western societies. Previous studies indicated that BMR is highly variable, but the cause of this variation is disputed. All studies agree that variation in fat-free mass (FFM) plays a major role, but effects of fat mass (FM), age, sex, and the hormones leptin, triiodothyrionine (T3), and thyroxine (T4) remain uncertain. OBJECTIVE: We partitioned the variance in BMR into within- and between-subject effects and explored the roles of FFM, FM, bone mineral content, sex, age, and circulating concentrations of plasma leptin, T3, and T4. DESIGN: This was a cross-sectional study of 150 white adults from northeast Scotland, United Kingdom. RESULTS: Only 2% of the observed variability in BMR was attributable to within-subject effects, of which 0.5% was analytic error. Of the remaining variance, which reflected between-subject effects, 63% was explained by FFM, 6% by FM, and 2% by age. The effects of sex and bone mineral content were not significant (P > 0.05). Twenty-six percent of the variance remained unexplained. This variation was not associated with concentrations of circulating leptin or T3. T4 was not significant in women but explained 25% of the residual variance in men. CONCLUSIONS: Our data confirm that both FFM and FM are significant contributors to BMR. When the effect of FM on BMR is removed, any association with leptin concentrations disappears, which suggests that previous links between circulating leptin concentrations and BMR occurred only because of inadequate control for the effects of FM.     

Clinical evaluation of the Sorin Synthesis oxygenator with integrated arterial filter

The use of arterial line filters has long been a standard of practice in the field of cardiopulmonary bypass. Sorin Biomedica has designed an adult hollow-fiber oxygenator that not only incorporates their Mimesys biomimicry coating technology but also has a 40-micron arterial filter as an integrated component of this unique membrane oxygenator. We did a prospective, randomized clinical trial of 54 Synthesis coated oxygenators and compared them with 54 uncoated Monolyth Pro oxygenators, the latter of which incorporated an external arterial line filter with a standard bypass loop There were few statistically significant differences found between the Synthesis group and the Monolyth group with regard to pressure differentials, hemodynamic resistance, and platelet drop. The Synthesis oxygenator did require less priming volume, but the amount was not significant. Platelet counts with the Phosphorylcholine coated Synthesis oxygenators, using crystalloid perfusates, was similar to our previously published data on platelet protection and Albumin perfusates. We conclude that the Sorin Synthesis oxygenator appears to have better flow characteristics than the Monolyth oxygenator, with the potential for lower priming volumes. The most clinically significant benefit comes from the elimination of the arterial filter bypass loop and the avoidance of inverting the arterial filter during priming.     

Adverse effects of anticholinergic medication on positive schizophrenic symptoms

In a series of 36 patients with acute schizophrenia flupenthixol dosage was blindly adjusted to give a fixed level of sedation. Patients were than randomly allocated to procyclidine or placebo. The patients receiving procyclidine experienced more positive schizophrenic symptoms and less severe extrapyramidal features by comparison with placebo patients. Blood levels of prolactin and flupenthixol estimated by radioimmunoassay were not significantly changed by the addition of procyclidine. Flupenthixol dosage and levels and prolactin levels were significantly related. There was no significant association between clinical and laboratory measures, with the exception that a curvilinear (inverted U) relationship was demonstrated between flupenthixol levels and antipsychotic and extrapyramidal effects. This relationship may be due to the fact that, in a study of this design, patients resistant to the effects of neuroleptic medication are likely to be given the highest doses. The findings support earlier claims that anticholinergic medication has adverse effects on schizophrenic symptoms.     

Effects of task difficulty on EEG measures of cerebral engagement

EEGs were recorded while subjects constructed 14 block designs of graded complexity, and also while reading and writing. Two measures of design difficulty were used: time to complete each construction and Ss' subjective ranking. For each task, average alpha power for each lead and R/L ratios (C₄/C₃, P₄/P₃) were calculated.Within-subject and group analyses both showed higher alpha power and higher R/L ratios with increasing difficulty. There were important differences between subjects: some showed significant increases in alpha power only on the left, some only on the right, some bilateral. Regardless of difficulty however, the R/L alpha ratios were significantly lower for block design than for writing, as in our previous studies.     

ALPRENOLOL DURING HALOTHANE ANAESTHESIA IN SURGIAL PATIENTS

Alprenolol 10 mg has been given intravenously to each of 70 atropinised patients lightly anaesthetised with halothane in oxygen. Evidence of reflex adrenergic overactivity of the heart was present in each patient before alprenolol was injected. Alprenolol completely blocked the chronotropic, inotropic and dysrhythmic reactions of the heart to reflex adrenergic stimulation. In the dose used the drug had no effect on the dromotropic activity of the heart.

ZUSAMMENFASSUNG

Alprenolol wurde in einer Dosis von 10 mg an 70 Patienten intravenös verabreicht, die atropinisiert und mit Halothan-Sauerstoff oberflächlich anaesthesiert waren. Bei allen Patienten waren vor der Injektion von Alprenolol Zeichen einer reflektorischen adrenergischen Hyperaktivität des Herzens vorhanden. Alprenolol blockierte die chronotropischen, inotropischen und dysrhytmischen Reaktionen des Herzens auf reflektorische adrenergische Stimulation komplett. In der angewandten Dosierung hatte das Mittel keinen Einfluss auf dromotrope Aktivität des Herzens.     

Chest pain among adolescents with anorexia nervosa

Chest pain is common among adolescents. However, chest pain among adolescents with eating disorders is unique. We report a case of an anorexic adolescent presenting to the emergency room with acute onset of chest pain due to spontaneous pneumomediastinum. The pathophysiology, etiology, and risk factors of chest pain among adolescents with anorexia nervosa are reviewed.     

Haematological changes in African children who received short-term prophylaxis with nevirapine and zidovudine at birth

We assessed the safety of short-term antiretroviral prophylaxis to prevent mother-to-child transmission (MTCT) of HIV by monitoring haematological changes in children up to the age of 18 months. Babies of HIV-infected women were randomised at birth to receive a single dose of nevirapine (NVP) alone or with zidovudine (ZDV) twice daily for a week. Based on the time of presentation to the labour ward, mothers of these babies might or might not have received intrapartum NVP. Complete blood counts were performed at birth and at 1.5, 3, 6, 9, 12, 15 and 18 months. Babies' HIV status was determined by HIV-1 RNA testing. A total of 1755 babies were included in the study. Age-specific mean haemoglobin levels and prevalence of anaemia (haemoglobin < 10 g/dL) were not significantly different in cases where only the babies received a single dose of NVP and cases where NVP was given to mother/infant pairs or additional ZDV to the baby. Among HIV-infected children compared with uninfected children, the age-specific frequency of anaemia was significantly greater, anaemia started earlier and recovery to normal levels was slower and prolonged. A reversible granulocytopenia was observed in all children between 1.5 and 3 months of age. HIV infection significantly increased the children's risk of death. Antiretroviral prophylaxis appeared to protect against anaemia and child death. Short regimens of antiretrovirals to prevent MTCT of HIV are not associated with long-term adverse haematological changes.     

Regional regenerative potential of meniscal cartilage exposed to recombinant insulin-like growth factor-I in vitro

It is well recognised that meniscal tears situated within the inner, avascular region do not heal. We investigated the potential effect of insulin-like growth factor-I (IGF-I) in promoting regeneration of meniscal tissue in the inner, middle and outer zones of the meniscus. Sheep menisci were harvested and monolayer cell cultures prepared. Various concentrations of IGF-I were used in the presence or absence of 10% fetal calf serum (FCS). We measured the uptake of radioactive thymidine, sulphur, and proline to assess cell proliferation and formation of extracellular matrix (ECM). IGF-I, in the presence or absence of FCS, increased the formation of DNA and ECM in all meniscal zones. However, the response of the cells from the avascular zone was greater than that from the vascular zone. Our findings indicate that fibrochondrocytes cultured from avascular meniscal tissue have the ability to regenerate when exposed to anabolic cytokines such as IGF-I.