[The effect of fatty emulsions with distinct triglyceride compositions on the lipid metabolism of the septic patient]. / Influencia de dos emulsiones grasas con distinta composición de triglicéridos sobre el metabolismo lipídico del paciente séptico.

OBJECTIVE: To assess the effects on the intravascular lipid mechanism of fatty emulsions with an identical lipid concentration and a different triglyceride composition administered as part of the total parenteral nutrition (TPN) in septicemic patients hospitalized in the intensive care unit (ICU). One emulsion will be made up of long chain triglycerides, LCT (20% Intralipid) (group I) and the other will be made up by a mixture of medium- and long-chain triglycerides, MCT/LCT (1:1) (20% Lipofundina) (group II). AREA: Vall d'Hebrón General University Hospital. Intensive care unit, Biochemistry laboratory, nutritional support unit, and Department of Pharmacy. PATIENTS: 12 septicemic patients who required TPN were studied, and these patients were randomly given one of the two lipid emulsions for a five day period. Prior to initiating the TPN and before ending it, blood samples were drawn for the analysis of the lipoprotein components VLDL, LDL, and HDL isolated by ultracentrifugation, and the basic lipid and nutritional parameters. RESULTS: The baseline statistical analysis shows that even though both groups are not comparable, the composition of the VLDL, LDL, and HDL lipoproteins differs from the reference values. After five days of TPN, the metabolic behavior of the groups is different, in group I the concentrations of reactive C protein (RCP) decreased as did the HDL phospholipids, while group II presented an increase in the plasma triglyceride levels, the VLDL cholesterol, the LDL triglycerides, and the HDL proteins. CONCLUSIONS: Septicemic patients present in altered lipoprotein pattern that tends to normalize after 5 days of lipid emulsions administration.

[Results of multicenter evaluation of reagents for determination of sodium, potassium and chloride ions using enzyme activation]. / Ergebnisse der multizentrischen Evaluierung von Reagenzien zur Bestimmung von Natrium-, Kalium- und Chloridionen mittels Enzymaktivierung.

We present the results of a multicentre evaluation with Boehringer Mannheim/Hitachi instruments of new "enzymatic" methods for the determination of Na+, K+, and Cl- in serum or plasma. The between-day coefficient of variation was less than 1.4% (Na+), less than 2.6% (K+) and less than 1.7% (Cl-). The linear range of the assays were at least 80 to 200 mmol/l (Na+), 1.5 to 17 mmol/l (K+) and about 30 to at least 200 mmol/l (Cl-). The comparisons with routine flame atomic emission spectrometry and coulometry showed a satisfactory agreement of the test results. The "enzymatic" assays are insensitive to even grossly elevated levels of bilirubin and lipids (sodium, potassium, and chloride assays), NH4+ (potassium assay) and amylase (chloride assay). Interference by various drugs was not detected. Since the new methods can easily be adapted to photometric clinical chemistry instruments, they represent a valuable alternative to the use of ion-selective electrodes, flame atomic emission spectrometry and coulometry.

Determination of amphotericin B in human serum by liquid chromatography.

A rapid reversed-phase high-performance liquid chromatographic method with a 30-mm long column is described for assaying amphotericin B in serum. After deproteinization of serum samples with methanol, the supernatant was injected onto a reversed-phase C18 column, using 2.5 mM Na2EDTA-acetonitrile (70:30, v/v) as the mobile phase. Amphotericin B was eluted at 1.5 min. Calibration plot of the peak area against concentration was linear from 0.05 to 25 micrograms/ml (C.V. of 3%). Within-day and day-to-day imprecision (C.V.) ranged between 1.33% and 3.61%. The application was evaluated in 55 serum samples from patients treated with amphotericin B.

Gentamicin pharmacokinetics in adults with bacterial endocarditis.

The pharmacokinetics of gentamicin in adult patients with endocarditis were studied. The records were reviewed for 64 patients treated for bacterial endocarditis and for whom serum gentamicin concentrations had been requested between May 1990 and May 1993. The patients were divided into those with serum creatinine concentration (SCr) <1.2 mg/dL and those with SCr > or = 1.2 mg/dL. The measured serum gentamicin concentrations, patient demographic information, dosage interval, and SCr were entered into a pharmacokinetics program for analysis. The pharmacokinetic values evaluated were steady-state distribution volume (V), clearance (CL), elimination rate constant (k), and half-life (t1/2). The mean +/- S.D. t1/2 and V of gentamicin were 4.7 +/- 2.4 hr and 0.29 +/- 0.11 L/kg. Half-life was correlated with SCr and V. These two variables may explain 66% of the variation in t1/2. No difference in V was observed between patients with normal versus abnormal SCr. Men had a lower k than women. V and CL were lower in patients under age 60 than in older patients. Adult patients with endocarditis may have expanded gentamicin V. V and CL accounted for most of the variation in gentamicin t1/2.

Determination of free serum didanosine by ultrafiltration and high-performance liquid chromatography.

An isocratic reversed-phase high-performance liquid chromatographic method was developed to determine free didanosine concentrations in human serum. An ultrafiltration technique was used to recover didanosine from the samples. didanosine was analyzed using a 150 mm x 3.9 mm I.D. Nova-Pak phenyl column and a mobile phase of 0.02 M sodium citrate (pH 5)-isopropanol (97.5:2.5, v/v) with detection set at 250 nm. Linearity was verified from 25 to 3000 ng/ml. The limit of detection at a signal-to-noise ratio of 3 was 25 ng/ml. The mean recovery of didanosine added to serum at 50, 100, 250 and 750 ng/ml was 97.4%, 97.3%, 92.9% and 95.4%, respectively. A within-day variation of 3.6% at 50 ng/ml and 1.7% at 250 ng/ml, and a day-to-day variation of 9.3% at 50 ng/ml and 3.6% at 230 ng/ml were found. Stability studies indicated that didanosine is stable in serum for at least 8.5 months at 20 degrees C, 4 degrees C and -20 degrees C.