Clinical,hematologic, and immunologic effects of interleukin-10 in humans

We conducted a double-blind, placebo-controlled study to investigate the safety, pharmacokinetics, and immunological properties of interleukin-10 (IL-10) administration in healthy humans. Volunteers received a single intravenous bolus injection of recombinant human IL-10 (1, 10, or 25g/kg) or placebo. Cytokine production in whole blood and peripheral blood mononuclear cells (PBMC) was assessed before and 3, 6, 24, and 48 hr after the injection. Peak serum concentrations of IL-10 (15±1.1, 208±20.1, and 505±22.3 ng/ml) occurred after 2–5 min for 1, 10, and 25g/kg IL-10, respectively. The terminal-phase half-life was 3.18 hr. A transient leukocytosis (24–63% above baseline) was observed 6 hr after injection, which coincided with a dose-dependent decrease (12–24%) in neutrophil superoxide generation. There was a marked inhibition (60–95%) of endotoxin-induced IL-6 production from whole blood in each group receiving IL-10. Production of IL-8 in endotoxin-stimulated blood was reduced in the 10g/kg group. In PBMC stimulated with phytohemagglutinin and phorbol ester, there was a decrease (72–87%) in interferon- (IFN) production 6 hr after IL-10 with a return to pre-IL-10 levels after 24 hr. This reduction was only partially associated with a decrease in the number of CD2-bearing cells. We conclude that IL-10 administration into humans is without significant side effects, and a single injection reducesex vivo production of IL-6, IL-8, and IFN.     

Effects of single intravenous doses of recombinant human interleukin-10 on subsets of circulating leukocytes in humans

Recombinant human interleukin-10 (rhIL-10) is a potent and specific immunomodulatory agent which inhibits endotoxin-stimulated pro-inflammatory cytokine production by monocytes, blocks T-lymphocyte activation by antigen presenting cells, and modulates T(H)1/T(H)2 balance in immune responses. In previous clinical trials, rhIL-10 administered to healthy volunteers induced rapid and transient elevations of neutrophil and monocyte counts and reductions of lymphocyte counts in addition to suppression of endotoxin-stimulated whole blood cytokine synthesis. We sought to better characterize the effects of rhIL-10 on immunophenotypically defined subsets of circulating leukocytes that could be relevant to its immunomodulatory effects. Healthy volunteers were given single doses of 10 microg/kg rhIL-10 (n = 8) or equivalent placebo (n = 4) by intravenous injection. Significant changes of circulating leukocytes included transiently increased neutrophils and monocytes with parallel increases of CD33+ and CD14+ cells. Total lymphocytes as well as total CD3+, CD3+/CD4+ and CD3+/CD8+ cells transiently decreased. Mean fluorescence intensity of CD11a (integrin alpha-chain subunit of lymphocyte function antigen-1, LFA-1) on lymphocytes transiently but significantly decreased, suggesting a mechanism for transient alteration of lymphocyte trafficking. In addition, mean fluorescence intensity of HLA-DR (major histocompatibility class II) on CD14+ cells (predominantly monocytes) transiently but significantly decreased, implying a possible alteration of antigen presenting function. Further study will be required to elucidate the immunomodulatory roles and potential clinical significance of these hematologic changes in therapeutic trials of rhIL-10 in patients with chronic inflammatory and autoimmune diseases.     

Pharmacokinetics of flutamide in patients with renal insufficiency

AIMS: The aim of this study was to determine the pharmacokinetic parameters of flutamide, a nonsteroidal antiandrogenic compound, and its pharmacologically active metabolite, hydroxyflutamide, in renal insufficiency. Haemodialysis (HD) clearance of flutamide and hydroxyflutamide was also determined. METHODS: Pharmacokinetic parameters were assessed for flutamide and hydroxyflutamide in 26 male subjects with normal renal function (creatinine clearance by 24 h urine collection, CLcr, greater than 80 ml min(-1) 1.73 m(-2); n=6) or reduced renal function; CLcr=50-80 (n=7), 30-49 (n=3), 5-29 (n=4), and <5 ml min(-1) 1.73 m(-2)-HD (n=6), following a single, oral 250 mg flutamide dose. Subjects undergoing HD received a second 250 mg dose of flutamide 4 h prior to HD; blood and dialysate were collected during HD to determine dialysability of flutamide and hydroxyflutamide. RESULTS: Cmax, tmax, AUC, t1/2, and renal clearance of flutamide and hydroxyflutamide did not differ between groups. Less than 1% of the dose appeared in dialysate as hydroxyflutamide. No serious adverse events were observed. CONCLUSIONS: Renal function did not affect flutamide nor hydroxyflutamide disposition. HD did not alter hydroxyflutamide pharmacokinetics. Dosing adjustments for renal impairment or HD are not indicated for flutamide.     

The penetration of ceftibuten into the respiratory tract.

STUDY OBJECTIVE: To determine the penetration of ceftibuten into various respiratory tissues and fluids. DESIGN: Single-dose, open-label, pharmacokinetic study. SETTING: Veterans Administration Medical Center. PATIENTS: Twelve hospitalized men aged 34 to 75 years with a variety of noninfectious pulmonary symptoms/diseases. INTERVENTIONS: Patients received a single oral dose of ceftibuten, 200 mg, prior to undergoing diagnostic fiberoptic bronchoscopy. Plasma samples for the determination of ceftibuten concentrations were collected pretreatment and up to 12 h postdosing. Nasal secretions, tracheal secretions, BAL fluid, and lung tissue from a biopsy were obtained at bronchoscopy from 2 to 7 h postdosing. MEASUREMENTS AND RESULTS: Mean pharmacokinetic parameters for ceftibuten in plasma were the following: maximum observed plasma concentration (Cmax), 8.77 microg/mL; time to reach Cmax, 2.2 h; area under the plasma concentration-time curve extraploated to infinity, 49.21 microg/h/mL; and terminal elimination half-life, 3.17 h. These parameters were similar to those obtained in studies using healthy volunteers. Mean penetration of ceftibuten into nasal, tracheal, and bronchial secretions was 47%, 50%, and 30%, respectively. Mean penetration into BAL fluid was 81%, whereas penetration into lung tissue was 39%. No patient experienced any adverse effects related to ceftibuten. CONCLUSIONS: Ceftibuten penetrates well into various tissues and fluids of the upper and lower respiratory tracts. The results support the activity of ceftibuten in the treatment of upper and lower respiratory tract infections.     

A collaborative assessment of workload and patient care needs in four rehabilitation facilities.

This article describes the process used by nurse executives at four freestanding rehabilitation facilities to implement and validate an interactive patient classification system. The research process involved defining critical indicators, measuring workloads by level of staff, and validating the number of care hours for the levels of patient classification. The database enabled the four consortium members to share their knowledge, resources, and costs of implementing a patient classification system, and it provides a benchmark of rehabilitation services. The study data are being used in making staffing decisions, preparing and defending budgets, and identifying the cost of care by disability classification.     

Pharmacokinetics and metabolism of [14C]rosaramicin in dogs.

The pharmacokinetics and metabolism of [14C]rosaramicin were studied in dogs after intravenous (i.v.; 10 mg/kg [bodyweight]) and oral (25 mg/kg) administration. After i.v. administration, rosaramicin levels in plasma declined rapidly, with half-lives of 0.22 h for the distribution phase and 0.97 h for the elimination phase. The apparent volume of distribution was 3.43 liters/kg, and the total body clearance was 106 mg/min . kg, indicating extensive distribution in tissue or metabolism or both. The absorption of oral solution was 58%, and the absolute bioavailability of rosaramicin was 35%. The plasma area under the curve of unchanged rosaramicin was only 5% that of total radioactivity after oral administration and 8% after i.v. administration, indicating extensive metabolism of the drug. The total radioactivity excreted in urine accounted for only 24% of the i.v. dose and 17% of the oral dose. Fecal radioactivity accounted for 71% of the i.v. dose and 68% of the oral dose. Several metabolites were observed in the plasma and urine. The amount of unchanged rosaramicin in urine (1 to 2% of the dose) was quite small after drug administration by either route.     

Comparative pharmacokinetics of aminoglycoside antibiotics in guinea pigs.

The pharmacokinetics of netilmicin, gentamicin, and tobramycin in plasma and in perilymph of guinea pigs were studied after a single intravenous injection of 40 mg/kg. Detailed pharmacokinetic analysis of the plasma drug concentration-time data up to 36 h after the intravenous dose revealed that the pharmacokinetics of the aminoglycoside antibiotics can be best described as a three-compartment open model. The disposition half-lives (t1/2) in plasma of the three antibiotics were comparable and within the following ranges: t1/2 alpha of 0.09 to 0.16 h; t1/2 beta of 0.88 to 1.01 h; and t1/2 gamma of 7.87 to 8.29 h. The volume of distribution in the central compartment and the total body clearance of netilmicin (294 ml/kg, 5.74 ml/min per kg) were greater than those of gentamicin (160 ml/kg, 3.40 ml/min per kg) and tobramycin (204 ml/kg, 4.63 ml/min per kg). Pharmacokinetic analysis of the perilymph drug concentration-time data indicated that all three antibiotics penetrated the perilymph readily, but netilmicin cleared from the perilymph compartment faster than gentamicin and tobramycin. The maximum perilymph drug concentrations were 4.17, 8.05, and 6.78 micrograms/ml and occurred at 1, 2, and 4 h for netilmicin, gentamicin, and tobramycin, respectively. The ratio of area under the curve of perilymph to plasma was lowest for netilmicin (0.27), followed by gentamicin (0.39) and tobramycin (0.57). These results suggest that the differences in pharmacokinetics and concentrations of netilmicin in the perilymph may account for less ototoxic liability of netilmicin compared with gentamicin and tobramycin.     

Multiple-dose pharmacokinetics of ceftibuten in healthy volunteers.

The pharmacokinetics of ceftibuten, a new cephalosporin antibiotic, and its conversion product, ceftibutentrans, were studied in healthy male volunteers following daily oral administration of a 400-mg capsule for 7 days. Mean concentrations of ceftibuten in plasma obtained on day 5 were similar to those obtained on day 7. Analysis of variance indicated that the concentrations in plasma on days 5 and 7 were at steady state. The mean accumulation factor was 1.14 for day 5 and 1.13 for day 7. The half-life (2.4 h) was independent of the duration of drug administration, and the mean maximum concentration of drug in plasma was 18 to 19 micrograms/ml. Urinary excretion was the major elimination route for ceftibuten, by which 57 to 59% of the drug was excreted unchanged over a 24-h period. The amounts of ceftibuten-trans in plasma and urine were low.