Chemical and spatial analysis of protein loaded PLGA microspheres for drug delivery applications.

Polymer microspheres for controlled release of therapeutic protein from within an implantable scaffold were produced and analysed using complimentary techniques to probe the surface and bulk chemistry of the microspheres. Time of Flight - Secondary Ion Mass Spectrometry (ToF-SIMS) surface analysis revealed a thin discontinuous film of polyvinyl alcohol (PVA) surfactant (circa 4.5 nm thick) at the surface which was readily removed under sputtering with C(60). Atomic Force Microscopy (AFM) imaging of microspheres before and after sputtering confirmed that the PVA layer was removed after sputtering revealing poly(lactic-co-glycolic) acid(PLGA). Scanning electron microscopy showed the spheres to be smooth with some shallow and generally circular depressions, often with pores in their central region. The occurrence of the protein at the surface was limited to areas surrounding these surface pores. This surface protein distribution is believed to be related to a burst release of the protein on dissolution. Analysis of the bulk properties of the microspheres by confocal Raman mapping revealed the 3D distribution of the protein showing large voids within the pores. Protein was found to be adsorbed at the interface with the PLGA oil phase following deposition on evaporation of the solvent. Protein was also observed concentrated within pores measuring approximately 2 µm across. The presence of protein in large voids and concentrated pores was further scrutinised by ToF-SIMS of sectioned microspheres. This paper demonstrates that important information for optimisation of such complex bioformulations, including an understanding of the release profile can be revealed by complementary surface and bulk analysis allowing optimisation of the therapeutic effect of such formulations.

The child as proband. High prevalence of unrecognized and untreated hyperlipidemia in parents of hyperlipidemic children.

The authors evaluated the lipids of parents of hypercholesterolemic children to assess the prevalence of unrecognized and/or untreated hyperlipidemia. Biologic parents of 34 children had measurements of total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides (n = 47) or total cholesterol only (n = 14). Lipid abnormalities were defined according to guidelines established by the National Cholesterol Education Program. Abnormal values were defined as total cholesterol greater than 240 mg/dl, low-density lipoprotein (LDL) cholesterol greater than 160 mg/dl, HDL cholesterol less than 35 mg/dl, and triglycerides greater than 250 mg/dl. Borderline values were defined as total cholesterol between 200 and 240 mg/dl and LDL cholesterol between 130 and 160 mg/dl. Abnormal values were found in 32/61 (52%) and borderline values were found in 12/61 (20%) parents. Of the abnormal parents, 13/32 (41%) had unrecognized or known but untreated hyperlipidemia, and 9/12 (75%) of the borderline parents had unrecognized abnormalities. In all families where both parents were tested, at least 1 had a lipid abnormality. The authors conclude that when children with hypercholesterolemia are identified, parents should also have lipids assessed. Treatment programs for children should also be directed at the parents.

The epidemiology of aerobic dance injuries.

Aerobic dance is currently the largest organized fitness activity primarily for women in the United States. In an attempt to identify and characterize the health problems associated with it, 351 students and 60 instructors from six facilities were followed for 16 weeks with weekly telephone calls. Of the 327 medical complaints reported during 29,924 hours of documented activity, only 84 (0.28 per hundred hours) resulted in any disability and only 2.1% required medical care. The shin/leg, foot and ankle accounted for nearly two-thirds of the injuries. Instructors were twice as likely to be injured as students. Both a history of prior orthopaedic problems and a lack of involvement in other fitness activities resulted in higher injury rates. Injury rates were influenced by the design and conduct of the aerobic program but not by brand of shoe or type of flooring. Aerobic dance appears to offer students the potential for fitness enhancement with a minimal risk of injury.