αCaMKII controls the establishment of cocaine's reinforcing effects in mice and humans

Although addiction develops in a considerable number of regular cocaine users, molecular risk factors for cocaine dependence are still unknown. It was proposed that establishing drug use and memory formation might share molecular and anatomical pathways. Alpha-Ca²⁺/calmodulin-dependent protein kinase-II (αCaMKII) is a key mediator of learning and memory also involved in drug-related plasticity. The autophosphorylation of αCaMKII was shown to accelerate learning. Thus, we investigated the role of αCaMKII autophosphorylation in the time course of establishing cocaine use-related behavior in mice. We found that αCaMKII autophosphorylation-deficient αCaMKII^T286A mice show delayed establishment of conditioned place preference, but no changes in acute behavioral activation, sensitization or conditioned hyperlocomotion to cocaine (20 mg kg⁻¹, intraperitoneal). In vivo microdialysis revealed that αCaMKII^T286A mice have blunted dopamine (DA) and blocked serotonin (5-HT) responses in the nucleus accumbens (NAcc) and prefrontal cortex after acute cocaine administration (20 mg kg⁻¹, intraperitoneal), whereas noradrenaline responses were preserved. Under cocaine, the attenuated DA and 5-HT activation in αCaMKII^T286A mice was followed by impaired c-Fos activation in the NAcc. To translate the rodent findings to human conditions, several CAMK2A gene polymorphisms were tested regarding their risk for a fast establishment of cocaine dependence in two independent samples of regular cocaine users from Brazil (n=688) and Switzerland (n=141). A meta-analysis across both samples confirmed that CAMK2A rs3776823 TT-allele carriers display a faster transition to severe cocaine use than C-allele carriers. Together, these data suggest that αCaMKII controls the speed for the establishment of cocaine''s reinforcing effects.     

Retrospective Clinical Investigation of the Impact of Early Treatment of Children with Down's Syndrome According to Castillo-Morales

BACKGROUND: Infants and toddlers with Down's syndrome are treated at the Department of Orthodontics, University of Frankfurt/Main only when the tongue protrudes over the lower lip, hindering mouth closure. No plate therapy is applied in patients with less tongue protrusion. This study aimed to assess objectively the treatment effects of stimulation plate therapy after Castillo-Morales at this early stage of development. PATIENTS AND METHOD: The follow-up covered 33 children, 20 of whom showed no mouth closure with the tongue resting protrusively on the lower lip at first examination at the age of 8 months. These 20 children received orthodontic treatment based on a stimulation plate. The parents were advised to insert the plate four times a day for about half an hour respectively. The overall treatment time was ca. 2 years. The second group (13 children) received no early treatment, as the functional parameters were only slightly altered at the age of 7 months. At follow-up, the children of the treatment group were between 8.8 +/- 2.3, and those of the control group 8.9 +/- 3.0 years old. The children underwent clinical examination; the parents answered a questionnaire. Additionally, study casts and intraoral photographs were taken along with frontal and profile photographs. The factors assessed were various functions, dentition, facial development, and subjective rating of the parents. RESULTS: In contrast to the initial findings, no difference between the two groups was found at follow-up. CONCLUSION: Early treatment using a stimulation plate thus appears to mitigate or even normalize the initially more severe dysfunctions recorded in the study group as compared to the controls.     

Hippocampus-dependent learning and memory is impaired in mice lacking the Ras-guanine-nucleotide releasing factor 1 (Ras-GRF1).

Previous results have suggested that the Ras signaling pathway is involved in learning and memory. Ras is activated by nucleotide exchange factors, such as the calmodulin-activated guanine-nucleotide releasing factor 1 (Ras-GRF1). To test whether Ras-GRF1 is required for learning and memory, we inactivated the Ras-GRF1 gene in mice. These mutants performed normally in a rota-rod motor coordination task, and in two amygdala-dependent tasks (inhibitory avoidance and contextual conditioning). In contrast the mutants were impaired in three hippocampus-dependent learning tasks: contextual discrimination, the social transmission of food preferences, and the hidden-platform version of the Morris water maze. These studies indicate that Ras-GRF1 plays a role in hippocampal-dependent learning and memory.     

A Replication Study of Reducing the Risk, a Theory-Based Sexuality Curriculum for Adolescents

ABSTRACT: Reducing the Risk is a theory-based, sexuality education curriculum shown to influence the knowledge and behaviors of secondary students. This study determined whether the behavioral effects of the curriculum could be duplicated in a southern, rural state. In a quasiexperimental design, pretest and posttest inventories were administered to students in treatment and comparison groups to determine the influence of Reducing the Risk on sexual behaviors. Results of the 18-month study indicated students receiving the curriculum significantly delayed initiating sexual intercourse. Sexually active students in the treatment group were significantly more likely to protect themselves from STD/HIV and pregnancy than sexually active students in the comparison group. In addition, students receiving Reducing the Risk showed a significant increase in parent-child communication about sexual issues. These results reinforce previous research that found positive behavioral effects for students receiving the Reducing the Risk curriculum     

Radioimmunoassay of Endothelin in Human Plasma

A specific and sensitive radioimmunoassay (RIA) for determination of endothelin-1 (ET-1) in human plasma has been developed. Antibodies were raised in rabbits using synthetic ET-1 conjugated to thyroglobulin as immunogen. The antibodies obtained were used at a final dilution of 1:300,000 yielding maximum binding of 61.7 ± 3.0% (mean ± 1 SD, n = 20) of ¹²⁵I-ET-I. The ID50 (inhibitory dose 50%) was 4.5 ± 0.6 fmol/100 μl (mean ± 1 SD, n = 20). The sensitivity of the RIA was 0.33 fmol/100 μl standard solution. No cross reactivity was observed with endothelin-3, big-endothelin-1, atrial natriuretic factor, angiotensin 1 or angiotensin II. The cross-reactivity with endothelin-2 was 100%. Endothelin was extracted from acidified plasma with Sep-pak C18 cartridges and recovery of ET-1 added to normal plasma was 70.9 ± 10.3% (mean ± 1 SD, n = 12). The concentration of ET-1 in plasma from normal subjects was 1.5 ± 0.4 pmol/l (mean ± SD, n = 11) ranging from 1.0 to 2.2 pmol/1. Extracts of normal human plasma subjected to high performance liquid chromatography on a reverse phase C18 column showed one peak of immunoreactivity co-eluting with the standard for ET-1. From these data it is concluded that the immunoreactive material measured in normal plasma with the present RIA is identical to ET-1.     

Chromatographic enzyme immunoassay for T-2 toxin

Both the active ester and maleimide moieties of the cross-linking reagent, N-[(gamma-maleimidobutyryl)oxy]succinimide (GMBS), were found to react with the primary amino groups on ribonuclease (RNase). This largely inactivated RNase towards a polymeric (but not monomeric) substrate. Citraconylating the RNase first, so that essentially only a single primary amino group remained to react with GMBS, overcame this problem. The subsequent maleimido-citraconyl-RNase was used to prepare a 1:1.1 M conjugate of anti-T-2 toxin Fab' and RNase (Fab'-RNase) in a 76% yield. The conjugate was used to detect as little as 0.1 microgram of T-2 toxin based on the ability of T-2 toxin to specifically displace Fab'-RNase complexed to a T-2 agarose affinity gel.     

Haemodynamic and humoral effects of lower body negative pressure in normal, sodium-replete man during angiotensin-converting enzyme inhibition with captopril

The significance of the renin-angiotensin system (RAS) for circulatory homeostasis during gravitational stress (10 min of lower body negative pressure, LBNP, at -40 mmHg) was investigated in eight men on liberal sodium intake. The function of RAS was inhibited by a single oral dose of 100 mg captopril, an angiotensin-converting enzyme inhibitor. Plasma concentrations of renin and angiotensin I were normal before and increased after captopril and during LBNP. Plasma concentration of angiotensin II was normal before captopril, increased during LBNP, and fell to low values after captopril. Systolic blood pressure decreased more during LBNP after captopril than in the control situation. In three cases, the LBNP experiment after captopril had to be interrupted due to marked hypotension. Heart rate and plasma concentration of adrenaline increased above pre-captopril levels. In six subjects, plasma concentration of noradrenaline increased more during LBNP after captopril, less in two subjects, whereas the arginine vasopressin concentration increased more after captopril in all five subjects where measurements were available. The results demonstrate that RAS participates in blood pressure homeostasis also in sodium-replete, normal man. The enhanced increases in heart rate and plasma catecholamines after captopril do not suggest that sympathetic reflex activity during gravitational stress is blunted after captopril, in contrast to the evidence from animal experiments.     

Unchanged lithium clearance during acute amiloride treatment in sodium-depleted man

To evaluate the validity of the lithium clearance method as a marker of overall proximal tubular fluid delivery in moderately sodium-depleted humans, the effects of a single dose of 10 mg amiloride on lithium clearance and glomerular filtration-rate were studied in normal volunteers maintained on a sodium diet of 50 mmol/day. Amiloride caused no changes of the glomerular filtration-rate or of lithium clearance. The effects of amiloride on tubular sodium, potassium and water handling were in accordance with a distal tubular action of amiloride. The results suggest that significant distal lithium reabsorption does not occur in measurable amounts during moderate sodium depletion in humans. The lithium clearance method may, therefore, be used to assess proximal fluid delivery in man when dietary sodium intake is as low as in the present study.