ABSTRACT
Endothelial protection (measured by vital-dye staining and computerized planimetry) and viscoelastic retention during phacoemulsification with and without traumatic lens implantation were assessed in a rabbit model comparing four viscoelastics (Healon, Amvisc Plus, Occucoat, and Viscoat). No significant differences in cell damage were noted between unoperated on controls and groups that underwent atraumatic phacoemulsification with viscoelastic. Cell damage after traumatic lens insertion was reduced significantly by all four viscoelastics. Cell damage with and without traumatic lens implantation was significantly lower when viscoelastics were retained. Viscoat and Occucoat were significantly more likely to be retained than Healon.
Subject(s)
Cataract Extraction , Chondroitin Sulfates/therapeutic use , Endothelium, Corneal/drug effects , Hyaluronic Acid/therapeutic use , Lenses, Intraocular , Methylcellulose/analogs & derivatives , Animals , Cell Count/drug effects , Endothelium, Corneal/pathology , Hypromellose Derivatives , Methylcellulose/therapeutic use , RabbitsABSTRACT
Rigid fixation using plates and screws is an accepted mode of repair for facial fractures and osteotomies. To avoid potential complications associated with metal implants, bioresorbable implants are being developed. A study was performed to assess the strength over time of three bioresorbable polymeric screws for facial bone reconstruction. Screws of each polymer type and a titanium control were implanted in the periorbital bones of eight rabbits. Rabbits were euthanized at various time intervals. Pull-out testing and histological analysis were performed. Results showed varying degrees of resorption and screw pull-out strength dependent on time and polymer type, and no change in the control. This study demonstrates that bioresorbable screws can be used in bone, although the optimal choices for human implantation are yet to be determined.
Subject(s)
Bone Screws , Facial Bones/surgery , Polymers , Prostheses and Implants , Titanium , Animals , Biodegradation, Environmental , Facial Bones/pathology , Male , Materials Testing , Models, Biological , Orbit/pathology , Orbit/surgery , Pilot Projects , RabbitsABSTRACT
The quantity of protein and carbohydrate comprising the matrix of calcium oxalate monohydrate (COM) renal stones was found to decrease with distance from the surface of the stone. The average organic concentration of stones 3 to 30 mm in diameter ranged from 5.7% at the surface to 2.7% at the core. This concentration gradient suggests matrix involvement in a "growth front" on stone surfaces with migration of organic material from the "older" interior. The matrix distribution was not readily correlated with density variations or with the presence of hydroxyapatite or calcium oxalate dihydrate. Surface matrix concentrations were greater than amounts predicted by physical adsorption. Electron microscopy confirmed the presence of the organic-rich surface layer and also suggested that increase in stone size occurs predominantly by crystal growth with microcrystal aggregates as growth centers.
Subject(s)
Calcium Oxalate/analysis , Carbohydrates/analysis , Kidney Calculi/metabolism , Proteins/analysis , Amino Acids/analysis , Humans , Kidney Calculi/pathology , Minerals/analysisABSTRACT
Seven patients with a clinical diagnosis of infectious mononucleosis (IM) and detectable heterophil antibodies were found to have peripheral blood lymphocytes that were cytotoxic for lymphoid cells containing Epstein-Barr virus from a patient with Burkitt's lymphoma. The cytotoxic lymphocytes persisted in the peripheral circulation for up to 45 days. Patients who had had IM 1 to 5 years previously lacked such cytotoxic lymphocytes. Patients who had signs and symptoms of IM but no detectable heterophil antibodies lacked cytotoxic lymphocytes. The lymphocytes of one patient with IM showed progressive diminution of cytotoxic ability after prednisone treatment.
Subject(s)
Infectious Mononucleosis/immunology , Lymphocytes/immunology , Adult , Antibodies, Heterophile/isolation & purification , Cell Line , Cytotoxicity Tests, Immunologic , Herpesvirus 4, Human/immunology , Humans , Lymphocytes/drug effects , Lymphocytes/microbiology , Prednisone/pharmacology , Time FactorsABSTRACT
Leucocyte migration in the presence and absence of a soluble lung homogenate has been studied in a group of asymptomatic cigarette smokers. Results were expressed as migration indices. Controls consisted of age-matched subjects who had never smoked and had no past history of any pulmonary disease. The migration indices, the number of pack-years smoked and the results of pulmonary function studies were tested for correlation. The mean leucocyte migration index of the test group of sixteen smokers was significantly less than was that of the control group (P less than 0.001). Inhibition of leucocyte migration in the presence of the lung homogenate was not observed in any of the control subjects. Six of the sixteen asymptomatic cigarette smokers, however, were identified by inhibition of leucocyte migration in the presence of the lung homogenate. The number of pack-years which had been smoked did not correlate with the migration indices (r = -0.06); however, inhibition of leucocyte migration was not observed in subjects who had smoked less than 6 pack-years.