Closed medullary nailing for fractured shaft of the femur--a comparison between the Küntscher and the AO techniques

A retrospective review was made of 97 cases of fractured shaft of the femur treated with closed medullary nailing. A comparison was made between the Küntscher and the AO techniques with respect to union of the fracture, rehabilitation, complication and functional results. Patients treated with AO nails enjoyed more rapid recovery: 88 per cent of the fractures united in 12 weeks, 62 per cent walked with full weight bearing in 8 weeks and 78 per cent returned to work within 6 months. However, the functional results in both groups were comparable. The special technical considerations and complications in each group are discussed.     

Voltage-activated K+ currents in acutely isolated hippocampal astrocytes.

Hippocampal astrocytes were acutely isolated by papain treatment and mechanical trituration. Astrocytes were identified by their distinctive stellate morphology and immunocytochemical staining for glial fibrillary acidic protein. The electrophysiological properties of these cells were investigated using whole-cell voltage-clamp techniques. Three kinetically and pharmacologically distinct voltage-activated K+ currents were identified in most cells; they resembled the neuronal A-current, delayed rectifier, and inward rectifier. The activation threshold of the A-current was -40 mV with a time to peak that ranged from 10 msec at -20 mV to 6 msec at 100 mV. Steady-state inactivation was observed when the holding potential was positive to -100 mV. The current was half-inactivated at -60 mV and totally inactivated at -20 mV. The A-current was suppressed by 4-aminopyridine (4-AP). The delayed rectifier was activated by depolarizing pulses more positive than -40 mV and had a half time of activation that ranged from 18 msec at -20 mV to 10 msec at potentials more positive than 40 mV. This current did not inactivate during a 100 msec pulse and was suppressed by extracellular tetraethylammonium (TEA). An inwardly rectifying current was elicited by hyperpolarizing pulses more negative than -80 mV. This current was not blocked by extracellular TEA or 4-AP and was never observed in the presence of external Ba2+. Voltage-activated inward Na+ currents were never observed. Voltage-activated K+ channels may enhance the local K+ spatial buffering capabilities of the astrocyte syncytium when extracellular [K+] increases during neuronal activity.     

Transfer of digoxin across the placenta and into breast milk

Eleven mothers given digoxin throughout pregnancy because of rheumatic heart disease were studied. Digoxin was identified in the placenta and, for the first time, in milk. Paired cord and maternal blood samples obtained at parturition showed lower digoxin levels in cord blood than in maternal blood. The total tissue-bound digoxin level in the placenta correlated closely with maternal digoxin levels. These findings suggest strongly the presence of a placental barrier for digoxin. Similar digoxin concentrations (0.825 +/- 0.015 nmol/l) were found in milk samples obtained daily between the third and seventh days post partum. The half-life of digoxin in the newborn was 36.2 +/- 5.43 hours (Mean +/- SEM); thus all the digoxin present at birth would be excreted within 10 to 11 days.     

Pharmacokinetics of l-carnitine in man following intravenous infusion of dl-carnitine.

The pharmacokinetics of l-carnitine were studied in adult male patients following intravenous infusion of dl-carnitine hydrochloride-L-Carnitine appears to distribute into a rapidly perfused and then a more slowly perfused body space following administration. The overall apparent distribution volume Vd (ss) is consistent with extracellular body water. Serum levels of l-carnitine, from two different dose levels were adequately described by a two-compartment model. 80% of the administered dose was recovered in 24 hour post dose urine.