Stability of craniofacial PLLA/PGA copolymer bioabsorbable screws

The behavior of bioabsorbable plates and screws after implantation is a dynamic process that results in dimensional changes of the devices after surgery. Bioabsorbable plates frequently are recognized as changing because of their size, but bioabsorbable screws are less appreciated in this regard. How bioabsorbable screws may change after placement and whether their manufacturing method has an influence on size and shape after implantation needs further study. Using 1.5-mm diameter screws made of an oriented copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid (LactoSorb copolymer), screw dimensions were measured before and after soaking in an in vitro pH 7.4, 37 degrees C buffer environment. After 33 days of exposure to buffer, there were no changes in the physical appearance of the screws, and there was no change in dimensions or shape. The orientation of polymer materials in a bioabsorbable screw device improves its strength and can retard the rate of hydrolysis. However, the residual stresses in oriented screws theoretically can potentiate dimensional shift in the implants during hydrolysis. That such shift did not occur during the early phase of hydrolysis provides further evidence of the mechanism by which these types of screws can maintain biomechanical function throughout the bone-healing phase of the craniofacial skeleton.     

Diagnostic utility and factor structure of the PTSD Checklist in older adults

ABSTRACT Background: Little research has examined the diagnostic utility and factor structure of commonly used posttraumatic stress disorder (PTSD) assessment instruments in older persons. Methods: A total of 206 adults aged 60 or older (mean age = 69 years; range = 60-92), who resided in the Galveston Bay area when Hurricane Ike struck in September 2008, completed a computer-assisted telephone interview two-five months after this disaster. Using the PTSD Checklist (PCL), PTSD symptoms were assessed related both to this disaster and to participants' worst lifetime traumatic event. Total PCL scores were compared to PCL-based, Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV)-derived probable diagnoses of PTSD to determine optimal cut scores. Confirmatory factor analyses (CFAs) were conducted to evaluate PTSD symptom structure. Results: Receiver operating characteristic analyses indicated that a PCL score of 39 achieved optimal sensitivity and specificity in assessing a PCL-based, algorithm-derived DSM-IV diagnosis of worst event-related PTSD; and that a score of 37 optimally assessed probable Ike-related PTSD. CFAs revealed that a recently proposed five-factor model - comprised of re-experiencing, avoidance, numbing, dysphoric arousal, and anxious arousal factors - provided a better fitting representation of both worst event- and disaster-related PTSD symptoms than alternative models. Current Ike-related anxious arousal symptoms demonstrated a significantly stronger association with current generalized anxiety than depressive symptoms, thereby supporting the construct validity of this five-factor model of PTSD symptomatology. Conclusions: A PCL score of 37 to 39 may help identify probable PTSD in older persons. The expression of PTSD symptoms in older adults may be best characterized by a recently proposed five-factor model with distinct dysphoric arousal and anxious arousal clusters.     

DSM-IV personality disorders and coronary heart disease in older adults: results from The National Epidemiologic Survey on Alcohol And Related Conditions

We evaluated the relationship between seven personality disorders listed in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders and coronary heart disease (CHD) in a nationally representative sample of U.S. older adults. We analyzed data on 10,573 adults aged 60 or older from the National Epidemiologic Survey on Alcohol and Related Conditions. In our results, we found that 13.30% of older adults reported a diagnosis of CHD confirmed by a health professional. Age (odds ratio or OR = 1.04), morbid obesity (OR = 1.59), hypertension (OR = 2.30), nicotine dependence (OR = 1.39), any drug use disorder (OR = 2.13), and any mood disorder (OR = 1.87) increased the odds of having CHD. Female gender (OR = 0.72) and social drinking (OR = 0.71) decreased the odds of having CHD. Controlling for these variables, we found that avoidant (OR = 1.80), schizoid (OR = 1.63), and obsessive-compulsive (OR = 1.37) personality disorders increased the odds of having CHD. Personality disorders may increase the risk of CHD in older adults. Putative mechanisms and directions for future research are proposed.     

Specific impairments in visuospatial working and short-term memory following low-dose scopolamine challenge in healthy older adults

Scopolamine-induced deficits in cognitive and motor processes have been widely demonstrated in animals and humans, although the role of acetylcholine in working memory is not as well understood. This study examined the role of acetylcholine neurotransmission in visuospatial short term and working memory using the Groton Maze Learning Test (GMLT). The GMLT is a computerized hidden maze learning test that yields measures of component cognitive processes such as spatial memory, working memory, and visuomotor function, as well as their integration in trial-and-error problem solving. Healthy older adults were administered scopolamine (0.3 mg subcutaneous), the acetlycholinesterase inhibitor donepezil (5 mg oral), scopolamine with donepezil, or placebo. Compared to placebo, low-dose scopolamine led to performance deficits on all measures of the GMLT. The greatest scopolamine-induced deficits were observed in errors reflecting working memory processes (e.g., perseverative errors d=-2.98, and rule-break errors d=-2.49) and these impairments remained robust when statistical models accounted for scopolamine-related slowing in visuomotor speed. Co-administration of donepezil partially ameliorated scopolamine-related impairments and this effect was greatest for measures of working memory than short-term memory. By itself, donepezil was associated with a small improvement in visuomotor function. These results suggest that scopolamine disrupts processes required for rule maintenance and performance monitoring, in combination with visuomotor slowing and sequential location learning.