The effects of partial and total interosseous membrane transection on load sharing in the cadaver forearm.

This study was performed to examine the effects of partial and total transection of the interosseous membrane (IOM) on load transfer in the forearm. Twenty fresh frozen forearms were instrumented with custom designed load cells placed in the proximal radius and distal ulna. Simultaneous measurements of load cell forces, radial head displacement relative to the capitellum, and local tension within the central band of the IOM were made as the wrist was loaded to 134 N with the forearm at 90 degrees of elbow flexion and in neutral pronation supination. For valgus elbow alignment (radial head contacting the capitellum), mean force carried by the distal ulna was 7.1% of the applied wrist force and mean force transferred from radius to ulna through the IOM was 4.4%. For varus elbow alignment (mean 2.0 mm gap between the radial head and capitellum), mean distal ulna force was 28% and mean IOM force was 51%. Section of the proximal and distal one-thirds of the IOM had no significant effect upon mean distal ulnar force or mean IOM force. Total IOM section significantly increased mean distal ulnar force for varus elbow alignment in all wrist positions tested. The mean level of applied wrist force necessary to close the varus gap (89 N) decreased significantly after both partial IOM section (71 N) and total IOM section (25 N). The IOM became loaded only when the radius displaced proximally relative to the ulna, closing the gap between the radius and capitellum. As the radius displaced proximally, the wrist becomes increasingly ulnar positive, which in turn leads to direct loading of the distal ulna. This shift of force to the distal ulna could present clinically as ulnar sided wrist pain or as ulnar impaction after IOM injury.     

Methamphetamine Use Following Bariatric Surgery in an Adolescent

Bariatric surgery is increasingly popular as a therapeutic strategy for morbidly obese adolescents. Adolescence represents a sensitive period of psychosocial development, and children with considerable weight loss may experience greater peer acceptance, accompanied by both positive and negative influences. Substance abuse exists as one of these negative influences. We present the case of an adolescent bariatric surgical patient who abused methamphetamines in the postoperative period, with consequent nutritional instability. A concerted effort must be made in the preoperative assessment of adolescent bariatric patients to delineate a history of illicit drug use, including abuse of diet pills and stimulants. Excessive postoperative weight loss or micronutrient supplementation non-compliance should raise a suspicion of stimulant use and appropriate screening tests should be performed. The consequent appetite suppression may manifest with signs of malnutrition such as bradycardia, hypotension, and weakness. Inpatient nutritional rehabilitation and psychiatric assessment should be considered.     

Orlistat fails to alter postprandial plasma lipid excursions or plasma lipases in normal-weight male volunteers

OBJECTIVES: After 10 d of orlistat administration (120 mg three times/day), the primary objective was to determine the drug's effect on postprandial plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities on day 10 after an oral fat-load. The secondary objectives were to determine the effects of orlistat on 12 h postprandial measures of: (1) preheparin HTGL and LPL; and (2) serum triglycerides, very-low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and free fatty acids. METHODS: Twenty-four normal-weight, healthy male volunteers were randomized to either 120 mg orlistat (n=12) or placebo (n=12) three times a day with meals for 10 d. Preheparin LPL and HTGL activities and LPL specific activity were measured in the fasted state on days 1, 5, and 10. On days 5 and 10 the study medication (orlistat or placebo) was taken at the beginning of a fat-rich breakfast and serum lipid and lipoprotein levels monitored for 12 h postprandially. On day 10, 15 min postheparin HTGL activity was measured 8 h after the fat-rich breakfast. RESULTS: No differences were found between groups in fasting levels of preheparin LPL or HTGL activity or in LPL-specific activity on days 1, 5 and 10. No difference was found between the two treatment groups in postheparin HTGL activity 8 h after the fat-rich breakfast. Also, no differences were found between the two groups in plasma triglycerides or lipoproteins. CONCLUSION: The results indicate that the oral administration of orlistat (120 mg t. i.d.) does not significantly alter plasma triglycerides or lipoproteins, and that the inhibitory effect of orlistat on lipases is limited to the gastrointestinal tract and is not manifested systemically.     

MAPLE Deposition of Macromolecules

Macromolecules are poised to feature prominently as components in organic electronics, medical implants, drug delivery systems, and sensors. A common theme for the role polymers will play in all of these is as a thin film. In all applications, it is paramount to have precise control over film thickness, structure, morphology, surfaces roughness, etc. Here, matrix‐assisted pulsed laser evaporation (MAPLE) is reviewed as a route to processing polymer and other soft matter thin films with control over the above‐mentioned parameters. After briefly discussing the experimental setup and current proposed mechanism of film formation via MAPLE, the use of MAPLE to process thin films is highlighted for use in various technologies and applications. Future directions and challenges for MAPLE processing of thin films are also discussed.

     

Gene transfer to primary normal and malignant human hemopoietic progenitors using recombinant retroviruses

To study the feasibility of using retroviruses for gene transfer into human hemopoietic cells, various cell types were exposed to virus carrying the gene for neomycin resistance (neor). In preliminary studies using K562 cells as targets, we found that high viral titer and co-cultivation with viral producer cells rather than incubation in medium exposed to viral producer cells were important variables for achieving high frequencies of G418 resistant (G418r) colonies. The maximum frequency of G418r K562 colonies after co-cultivation with cells producing a neor virus titer of 4 X 10(6) cfu/mL was 60%. When primary human progenitors from normal marrow, fetal liver, or chronic myelogenous leukemia blood were exposed to high titer viral stocks, both with and without helper virus, under conditions optimized for K562 cells, maximum frequencies of G418r colonies were 3% to 16% for granulocyte macrophage progenitors and 2% to 6% for primitive erythroid progenitors. The presence of the neor gene in both G418r K562 and primary hemopoietic colonies was verified by Southern blot. Expression of the neor gene was shown by RNA spot blot. These data demonstrate efficient transfer and expression of the neor gene in both K562 cells and primary human hemopoietic cells from normal and leukemic individuals.