Ryanodine sensitive calcium release channel from left ventricle, septum, and atrium of canine heart.

OBJECTIVE: The aim was to consider the possibility that functionally distinct forms of the ryanodine sensitive calcium release channel are expressed in different regions of heart. METHODS: Membranous fractions enriched in ryanodine binding activity were isolated from canine left ventricular free wall, interventricular septum, and atrium. Ryanodine receptors (RyR) were purified by sucrose density gradient centrifugation, following solubilisation of sarcoplasmic reticular membranes with the detergent Chaps. Single channel currents were measured, upon reconstitution of sarcoplasmic reticular vesicles and the purified RyR into planar lipid bilayers. RESULTS: Ryanodine sensitive Ca2+ release channels from three different regions of canine heart displayed the same [3H]ryanodine binding and single channel characteristics. CONCLUSIONS: The left ventricular free wall, septum, and atrium of canine heart may express functionally related, if not identical, ryanodine receptor/Ca2+ release channels.

Stopping abuse before it occurs: different solutions for different population groups.

This paper reports on a conference at which participants reviewed indepth the literature on child abuse prevention and child development, as it pertains to different cultural and ethnic population groups, and identifies alternative prevention strategies for these different groups. The efficacy of the following interventions are analyzed: perinatal support programs, education for parents, treatment for abused children, early and periodic childhood screening and treatment programs; social skills training for children and young adults; mutual aid programs and neighborhood support groups; family support services such as crisis care; public information about child abuse and community development activities such as employment assistance. The paper concludes that although treatment services for different groups may be quite similar, prevention strategies must take account of the individual and unique values, norms and socialization patterns of different groups.

Is treatment too late: what ten years of evaluative research tell us.

Since 1974, the U.S. federal government has funded four major multiyear evaluation studies to determine the relative effectiveness of different approaches to the treatment of child abuse and neglect. A total of 89 different demonstration treatment programs were studied, and data on 3,253 families experiencing difficulties with abuse and neglect were gathered. Collectively, the studies document treatment approaches which improve clients' functioning (notably lay counseling and various group services including Parents Anonymous, group therapy, and parent evaluation) and suggest greater success with clients experiencing difficulty with sexual abuse than other forms of maltreatment. However, overall the studies show that one-third or more of the parents served by these intensive demonstration efforts maltreated their children while in treatment, and over one-half of the families served continued to be judged likely to mistreat their children following termination.

High-affinity [3H]PN200-110 and [3H]ryanodine binding to rabbit and frog skeletal muscle.

In vertebrate skeletal muscle, the voltage-dependent mechanism of sarcoplasmic reticulum (SR) Ca2+ release, commonly referred to as excitation-contraction (E-C) coupling, is mediated by the voltage-sensing dihydropyridine receptor (DHPR), which is believed to affect SR Ca2+ release through a physical interaction with the SR ryanodine receptor (RYR)/Ca2+ release channel. Scatchard analysis of ligand binding of [3H]PN200-110 to the DHPR and [3H]ryanodine to the RYR indicated the presence of high-affinity sites in muscle homogenates, with maximum binding (Bmax) values of 72 +/- 26 and 76 +/- 30 pmol/g wet wt for rabbit skeletal muscle, and 27 +/- 14 and 44 +/- 13 pmol/g wet wt for frog skeletal muscle, respectively. The Bmax values corresponded to a PN200-110-to-ryanodine binding ratio of 0.98 +/- 0.26 and 0.61 +/- 0.24 for rabbit and frog skeletal muscle, respectively, and were found by Student's t test to be significantly different (P < 0.02, n = 7). These results are compared with measurements with isolated rabbit skeletal muscle membrane fractions and discussed in relation to our current understanding of the mechanism of E-C coupling in skeletal muscle.