Double-lumen needle for percutaneous ureteral pressure-flow studies

Ureteral perfusion studies in patients without preexisting renal access currently must be intermittently interrupted for intrarenal pressure measurement. A double-lumen needle has been successfully placed in four patients (two with native and two with transplanted kidneys). This permits simultaneous perfusion and intrarenal pressure monitoring yet maintains the safety and ease of use of a single skinny needle.     

Thoracic gas volume in early childhood

A total body plethysmograph is descirbed which was used to study thoracic gas volume (TGV) in infants and young children from birth to 2 1/2 years, and was suitable for use even in very sick babies. Normal TGV values were obtained in 42 studies of 35 healthy infants and young children, and 16 children with abnormal lung volume are described. TGV correlated well with length, weight, chest circumference, and age in the healthy infants. A low TGV was found in children with respiratory difficulties after cardiac and thoracic surgery, in respiratory distress syndrome of the newborn, and in association with pulmonary infection and chest cage abnormalities. Abnormally high TGV was most frequently seen in infants with small airways disease.     

Electron immunocytochemical analysis of posterior hyaloid associated with diabetic macular edema

BACKGROUND: Tangential traction in the macula from a thickened posterior hyaloid of the vitreous has been implicated as a cause of diffuse diabetic macular edema. Vitrectomy with peeling of the posterior hyaloid has been shown to reduce retinovascular leakage and improve vision in select patients. We report a clinicopathologic correlation using electron microscopy and electron immunocytochemistry to characterize the membrane infiltrating the posterior hyaloid in two such patients. METHODS: Two patients presented with vision loss associated with diffuse diabetic macular edema and an attached, thickened, and taut posterior hyaloid. The patients underwent vitrectomy with peeling of the posterior hyaloid. The premacular posterior hyaloid specimens then were analyzed by electron microscopy with immunocytochemical staining for cytokeratin and glial fibrillary acidic protein. RESULTS: Both posterior hyaloid specimens contained collagen and a large cellular component. Immunogold labeling showed cells positive for glial fibrillary acidic protein or cytokeratin. With double labeling, no cells expressed both proteins simultaneously. Clinically, both patients had vision improvement and macular edema resolution after surgery. CONCLUSIONS: The thickened, taut posterior hyaloid observed in our patients with diabetic macular edema contained cells of glial and epithelial origin. This cellular infiltration may contribute to abnormal vitreomacular adherence and could play a role in the pathogenesis of macular edema in some patients with diabetes.     

Effects of particle exposure and particle-elicited inflammatory cells on mutation in rat alveolar epithelial cells

To investigate mechanisms underlying development of lung adenomas and carcinomas in rats exposed to poorly soluble particles the relationships between particle exposure, inflammation and mutagenesis in rat alveolar type II cells were characterized. Rats were exposed to saline or saline suspensions of 10 and 100 mg/kg of alpha-quartz, carbon black or titanium dioxide by intratracheal instillation. Fifteen months after exposure, bronchoalveolar lavage (BAL) cells were characterized as to number and type and lung histopathology performed. The alveolar type II cells were isolated and cultured in 6 thioguanine (6TG) containing media to select for mutation in the hprt gene. The potential contribution of lung inflammatory cells to in vivo mutagenic responses, were evaluated by co-culturing BAL cells with the rat alveolar epithelial cell line, RLE-6TN for 24 h and the RLE-6TN cells selected for 6TG resistance. Neutrophilic inflammation was detected in all rats exposed to 10 and 100 mg/kg of alpha-quartz and carbon black and 100 mg/kg titanium dioxide; epithelial hyperplasia was observed in rats exposed to 10 and 100 mg/kg of alpha-quartz and 100 mg/kg carbon black. Hprt mutation frequency was increased in alveolar type II cells from rats exposed to 10 and 100 mg/kg of alpha-quartz, 100 mg/kg carbon black and 100 mg/kg titanium dioxide. In vitro exposure of RLE-6TN cells to BAL cells from rats treated with 10 and 100 mg/kg of alpha- quartz or 100 mg/kg carbon black increased hprt mutant frequency. Both macrophage and neutrophil enriched BAL cell populations were mutagenic to RLE-6TN cells, however, the mutagenic activity appeared greatest for neutrophils. Addition of catalase to BAL cell:RLE-6TN co-cultures inhibited the increase in hprt mutation frequency. These studies demonstrate exposure of rats to doses of particles producing significant neutrophilic inflammation is associated with increased mutation in rat alveolar type II cells. The ability of particle- elicited macrophages and neutrophils to exert a mutagenic effect on epithelial cells in vitro supports a role for these inflammatory cells in the in vivo mutagenic effects of particle exposure. The inhibition of BAL cell-induced mutations by catalase implies a role for cell- derived oxidants in this response.      

Somatosensory evoked potentials in very preterm infants in relation to L-thyroxine supplementation

OBJECTIVE: To study the effect of L-thyroxine supplementation on neurologic maturation in very preterm infants with transient hypothyroxinemia. DESIGN: Randomized, double-blind, placebo-controlled, L-thyroxine supplementation trial. SETTING: Level III neonatal intensive care unit. SUBJECTS: A total of 200 infants <30 weeks' gestational age. INTERVENTION: Subjects were randomly assigned to receive L-thyroxine (8 microg/kg birth weight per day) or a placebo during the first 6 weeks of life. METHODS: Median nerve somatosensory evoked potentials were recorded, measuring cortical N1 peak latency at 2 weeks of age, at term, and at 6 months (corrected) age. RESULTS: Cortical N1 peak latency was not decreased significantly in the L-thyroxine group compared with the placebo group throughout the study period. CONCLUSION: L-Thyroxine supplementation during the first 6 weeks of life did not decrease cortical N1 peak latency in infants of <30 weeks' gestational age.