Calcium mobilization via intracellular ion channels, store organization and mitochondria in smooth muscle

In smooth muscle, Ca2+ release from the internal store into the cytoplasm occurs via inositol trisphosphate (IP3R) and ryanodine receptors (RyR). The internal Ca2+ stores containing IP3R and RyR may be arranged as multiple separate compartments with various IP3R and RyR arrangements, or there may be a single structure containing both receptors. The existence of multiple stores is proposed to explain several physiological responses which include the progression of Ca2+ waves, graded Ca2+ release from the store and various local responses and sensitivities. We suggest that, rather than multiple stores, a single luminally-continuous store exists in which Ca2+ is in free diffusional equilibrium throughout. Regulation of Ca2+ release via IP3R and RyR by the local Ca2+ concentration within the stores explains the apparent existence of multiple stores and physiological processes such as graded Ca2+ release and Ca2+ waves. Close positioning of IP3R on the store with mitochondria or with receptors on the plasma membrane creates ‘IP3 junctions’ to generate local responses on the luminally-continuous store

The Association Between BXO and Obesity in Boys Undergoing Circumcision

This study investigated whether boys with balanitis xerotica obliterans (BXO) have increased rates of obesity compared with boys with no concern for BXO (NCB). Boys ≤18 years old with circumcision pathology–confirmed BXO were compared with an age-matched group who had NCB during circumcision. Boys with BXO were found to have a mean body mass index of 70.64 percentile for age compared with 52.43 percentile in age-matched controls ( P = .0005). The rate of obesity was significantly higher in boys with BXO (42%) compared with 12.4% in boys with NCB (odds ratio = 5.12; 95% CI = 2.6 to 10.06). Given the increasing rates of childhood obesity and the long-term health consequences of both BXO and obesity, special attention should be paid to this population. Further research is needed to determine if BXO in obese children may represent an early indicator of a systemic disease process where intervention may be warranted