Identification of a Membrane Receptor for Retinol-Binding Protein Functioning in the Cellular Uptake of Retinal

Retinol-binding protein (RBP) is the transport protein that carries retinol in the circulation from the liver to its target tissues. The existence of a cell-surface receptor on the target cells, which mediates the uptake of retinol from RBP, has been known since 1975. Recently, it was identified as an integral transmem-brane protein named STRA6 that is inducible by retinoic acid in certain cancer cells. The receptor was found to be highly specific for RBP, with high affinity, and to be localized in all tissues known to require retinol for their function, particularly the pigment epithelium of the eye.     

Premenstrual symptoms in black and white community samples

Premenstrual syndrome specialty clinics are reported to be almost exclusively attended by white women. This racial discrepancy has raised the question of whether there is a lower prevalence or severity of symptoms during the premenstruum among black women. The authors evaluated selected premenstrual symptoms in a representative community-based sample and found no difference in the prevalence or severity of premenstrual symptoms reported by black and white women, except for a higher prevalence of food cravings among blacks. Exploration of broader sociocultural factors may explain the observed racial difference in seeking help for premenstrual complaints.     

Effects of using object self-stimulation as a reinforcer on the prevocational work rates of an autistic child

The purpose of this study was to examine the effects of object self-stimulation on the task-interrupting self-stimulatory behavior and prevocational work responses of a 13-year-old autistic boy. Using a multiple-baseline design across three diferent prevocational tasks, a systematic manipulation of object self-stimulation was associated with increases in correct rates and decreases in task-interrupting self-stimulatory behaviors. An analysis of these data indicates that self-stimulatory behavior may be shaped to facilitate performance proficiencies. Social validation information suggests that favorable generalized responding had occurred. On the basis of findings from this study, future research needs are discussed.     

Modification of Blood Vessel Diameter Following Perivascular Application of Botulinum Toxin-A

The purpose of this study was to demonstrate that perivascularly applied botulinum toxin-A (BTX) increases the diameter of treated blood vessels in a rat femoral vessel exposure model. Six adult Sprague–Dawley rats were used and bilateral femoral artery and vein exposures were performed. Five units of BTX were applied to the experimental side and an equal volume of sterile saline was applied to the control side. Digital images of the vessels were obtained at the following time points: pretreatment, immediately posttreatment, and postoperative days (POD) 1, 14, and 28. Vessel diameters were equivalent at baseline and immediately following application of BTX and saline. The BTX artery was significantly larger than the control artery on POD 1 and 14. The BTX treated artery was significantly larger than all other vessels on POD 14 (p < 0.05) as well as all prior time points (p < 0.01). Direct perivascular application of BTX increases the diameter of rat femoral vessels as early as POD 1. The affect is most robust on POD 14 where the artery was significantly larger than all other vessels at all time points. It is likely that the increased diameter of blood vessels results in an increased blood flow across the area of dilation. Such an increase in flow may serve to improve end-organ perfusion in microvascular procedures.     

Comparison of migration behavior between single and dual lag screw implants for intertrochanteric fracture fixation

Background  

Lag screw cut-out failure following fixation of unstable intertrochanteric fractures in osteoporotic bone remains an unsolved challenge. This study tested if resistance to cut-out failure can be improved by using a dual lag screw implant in place of a single lag screw implant. Migration behavior and cut-out resistance of a single and a dual lag screw implant were comparatively evaluated in surrogate specimens using an established laboratory model of hip screw cut-out failure.