Efficacy and safety of DALI LDL-apheresis at high blood flow rates: a prospective multicenter study.

Direct adsorption of lipids (DALI) is the first LDL-apheresis method compatible with whole blood. Usually, the blood flow rate is adjusted at 60-80 ml/min, which results in session times of about 2 hr. The present study was performed to test the safety and efficacy of low-density lipoprotein cholesterol (LDL-C) and lipoprotein (a) [Lp(a)] removal by DALI at high blood flow rates in order to reduce treatment time. Thirteen chronic DALI patients in seven centers suffering from hypercholesterolemia (LDL-C 162 +/- 42 mg/dl at baseline) and coronary artery disease were treated on a weekly or biweekly basis by DALI apheresis. The blood flow rate QB was held constant for at least two sessions, respectively, and was increased from 60 to 80, 120, 160, 200, and 240 ml/min. All patients had pre-existing av-fistulas. The anticoagulation was performed by a heparin bolus plus ACD-A at a ratio of citrate:blood ranging from 1:20 to 1:90. Clinically, the sessions were well tolerated and only 26/201 sessions (12%) of the treatments were fraught with minor adverse events. Acute LDL-C reductions (derived from LDL-C levels determined by lipoprotein electrophoresis) averaged 72/66/60/53/50/48% for QB=60/80/120/160/200/240 ml/min. Lp(a) reductions were 68/67/62/60/58/56%, whereas HDL-C losses were < or =10%. Routine blood chemistries and blood cell counts remained in the normal range. Treatment times averaged 142/83/45 min at Qb=60/120/240 ml/min. On average, DALI LDL-apheresis could be performed safely and effectively at high blood flow rates up to at least 120 ml/min in patients with good blood access, which significantly reduced treatment time from 142 to 83 min (-42%).

Carbon balance in tussock tundra under ambient and elevated atmospheric CO2.

Whole ecosystem CO2 flux under ambient (340 µl/l) and elevated (680 µl/l) CO2 was measured in situ in Eriophorum tussock tundra on the North Slope of Alaska. Elevated CO2 resulted in greater carbon acquisition than control treatments and there was a net loss of CO2 under ambient conditions at this upland tundra site. These measurements indicate a current loss of carbon from upland tundra, possibly the result of recent climatic changes. Elevated CO2 for the duration of one growing season appeared to delay the onset of dormancy and resulted in approximately 10 additional days of positive ecosystem flux. Homeostatic adjustment of ecosystem CO2 flux (sum of species' response) was apparent by the third week of exposure to elevated CO2. Ecosystem dark respiration rates were not significantly higher at elevated CO2 levels. Rapid homeostatic adjustment to elevated CO2 may limit carbon uptake in upland tundra. Abiotic factors were evaluated as predictors of ecosystem CO2 flux. For chambers exposed to ambient and elevated CO2 levels for the duration of the growing season, seasonality (Julian day) was the best predictor of ecosystem CO2 flux at both ambient and elevated CO2 levels. Light (PAR), soil temperature, and air temperature were also predictive of seasonal ecosystem flux, but only at elevated CO2 levels. At any combination of physical conditions, flux of the elevated CO2 treatment was greater than that at ambient. In short-term manipulations of CO2, tundra exposed to elevated CO2 had threefold greater carbon gain, and had one half the ecosystem level, light compensation point when compared to ambient CO2 treatments. Elevated CO2-acclimated tundra had twofold greater carbon gain compared to ambient treatments, but there was no difference in ecosystem level, light compensation point between elevated and ambient CO2 treatments. The predicted future increases in cloudiness could substantially decrease the effect of elevated atmospheric CO2 on net ecosystem carbon budget. These analyses suggest little if any long-term stimulation of ecosystem carbon acquisition by increases in atmospheric CO2.

Field water relations of a wet-tropical forest tree species, Pentaclethra macroloba (Mimosaceae).

The water relations of Pentaclethra macroloba (Willd.) Kuntze, a dominant, shade-tolerant, tree species in the Atlantic lowlands of Costa Rica, were examined within the forest canopy. Pressure-volume curves and diurnal courses of stomatal conductance and leaf water potential were measured in order to assess differences in water relations between understory, mid-canopy and canopy leaves. Leaves in the canopy had the smallest pinnules but the largest stomatal frequencies and stomatal conductances of the three forest levels. Osmotic potentials at full turgidity decreased with height in the forest; in the canopy and midcanopy they were reduced relative to those in the understory just enough to balance the gravitational component of water potential. Consequently, maximum turgor pressures were similar for leaves from all three canopy levels. Bulk tissue elastic modulus increased with height in the canopy. Leaf water potentials were lowest in the canopy and highest in the understory, even when the gravitational component was added to mid-canopy and canopy values. As a result, minimum turgor pressures were also lowest in the canopy compared to those at lesser heights, and approached zero in full sunlight on clear days.Osmotic potentials at each canopy level were similar for both wet and dry season samples dates suggesting that seasonal osmotic adjustment does not occur. Despite lowered predawn water potentials during the dry season, turgor was maintained in the understory by reduced stomatal conductances.

Effects of muzolimine and of a combination of hydrochlorothiazide/triamterene in healthy subjects and in nephrotic patients.

The diuretic effects of 30 mg muzolimine and 25 mg hydrochlorothiazide/50 mg triamterene were comparable in healthy subjects and nephrotic patients (serum albumin less than 32 g/l, creatinine clearance greater than 50 ml/min/1.73 m2). A single daily dose of 30 mg muzolimine or 25 mg hydrochlorothiazide/50 mg triamterene was sufficient in the majority of the investigated nephrotic patients. The different diuretic effects which were observed in nephrotic patients were not related to the severity of hypalbuminemia, but rather to differences in preceding diuretic treatment. Plasma levels and urinary excretion of unchanged muzolimine were comparable in healthy subjects and nephrotic patients after one day of diuretic treatment; after seven days of treatment plasma levels of muzolimine were significantly lower and urinary excretion significantly higher in nephrotic patients than in control subjects.