Serum and interstitial fluid apolipoprotein E levels in the healthy and in hyperlipoproteinemia type III as studied by radioimmunoassay

In order to study the relationships between serum lipoprotein lipid concentrations and the concentrations of apo E in serum and interstitial fluid, we have developed a specific, sensitive and rapid radioimmunoassay for this apolipoprotein. Studies of the interstitial fluid lipoproteins and of the gradient between the lipoprotein concentrations in interstitial fluid and serum may add to our understanding of the development of atherosclerosis and xanthomatosis. Serum, interstitial fluid, lipoproteins or standards were incubated with 125I-labelled apo E and rabbit antiserum against apo E for 90-120 min at room temperature. The immune complexes were harvested with the use of formalin-treated staphylococci. The displacement curves produced by standard and samples of serum, interstitial fluid and isolated lipoproteins were linear in logit-log plots and had identical slopes. Delipidation did not change the results and the recovery of added apo E to a serum sample was 96 +/- 5% (n = 5). Apo E was found in all major lipoprotein classes and the concentrations of apo E in serum and in interstitial fluid were 36 +/- 19 mg/l and 8 +/- 4 mg/l, respectively, in normals (n = 21) and 305 +/- 125 mg/ml and 20 +/- 9 mg/l, respectively, in patients with HLP type III (n = 11). Highly significant positive correlations were found in HLP type III between the interstitial fluid level of apo E and the corresponding concentrations of cholesterol and triglyceride. Interstitial fluid apo E concentrations were significantly correlated to apo E but not to the lipid levels in serum, indicating that only some subclasses of the serum lipoproteins are transported to the interstitial compartment.     

Lecithin cholesterol acyltransferase in human cerebrospinal fluid: reduced level in patients with multiple sclerosis and evidence of direct synthesis in the brain.

Several studies suggest that apolipoproteins and the low-density lipoprotein receptor are implicated in lipid transport in the brain. Given that cerebrospinal fluid has been reported to contain cholesteryl esterifying enzyme, and that lipid metabolism in the brain is abnormal in subjects with multiple sclerosis, we examined the cerebrospinal fluid from eight control subjects with a normal cerebrospinal fluid IgG index, and without active demyelinating disease, and from eight subjects (6 were diagnosed as having multiple sclerosis) with an increased IgG index and the presence of oligoclonal banding in the cerebrospinal fluid, for the presence of the enzyme lecithin cholesterol acyltransferase and apolipoprotein(a). None of the subjects demonstrated impairment of their blood-cerebrospinal fluid barrier, as estimated by the cerebrospinal fluid/serum quotient of albumin. Lecithin cholesterol acyltransferase was detected in the cerebrospinal fluid of all control subjects, being 0.12 +/- 0.06 microgram/ml (mean +/- SD) or about 2.2% of that in serum (5.4 +/- 1.4 micrograms/ml). The cerebrospinal fluid lecithin cholesterol acyltransferase index was 5.2 +/- 2.5, very similar to the cerebrospinal fluid index of apolipoprotein E, a protein known to be synthesized in the brain. Since lecithin cholesterol acyltransferase mRNA is also expressed in the brain, we can conclude that the protein is synthesized and secreted in the brain. The cerebrospinal fluid concentration of lecithin cholesterol acyltransferase in the subjects with active demyelinating disease or multiple sclerosis was only about one-half of that found in control subjects (0.06 +/- 0.02 microgram/ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

Radial immunodiffusion assay of apolipoprotein B in blood dried on filter paper--a potential screening method for familial type II hypercholesterolaemia

In the search for an effective neonatal screening programme for familial type II hypercholesterolaemia, we have developed and validated a radial immunodiffusion assay for measuring, in dried blood spots, the concentration of apolipoprotein B. The method has advantages over previously described methods, being cheaper, more robust, and suitable for partial automation. In 34 adults there was a close linear relationship between capillary and venous blood spot apolipoprotein B concentrations (r = 0.94), between capillary blood spot and serum apolipoprotein B also measured by radial immunodiffusion (r = 0.90), and between capillary blood spot apolipoprotein B and LDL cholesterol measured by ultracentrifugation (r = 0.85). Apolipoprotein B levels in serum and LDL cholesterol also correlated closely (r = 0.95, n = 40). In 30 normal 3- to 5-day old babies, heel prick blood spot apolipoprotein B levels were 280 +/- 70 mg/l (mean +/- SD) and 790 mg/l in one presumed heterozygote for familial hypercholesterolaemia. We conclude that serum apolipoprotein B measured by radial immunodiffusion accurately reflects adult LDL cholesterol levels, and that the assay, using dried blood spots on filter paper should permit both neonatal and adult screening programmes to detect familial hypercholesterolaemia.     

Methotrexate cerebrospinal fluid and serum concentrations after intermediate-dose methotrexate infusion

Twenty-nine children with acute lymphocytic leukemia were given 24-hr infusions of intermediate-dose methotrexate (MTX, 1000 mg/m2) with and without intrathecal (IT) MTX (12 mg/m2), followed by leucovorin rescue. There was substantial interpatient variability in MTX systemic clearance (98.3 +/- 51 ml/min/m2), inducing total steady-state serum MTX concentrations ranging from 5.4 to 33.7 microM. The cerebrospinal fluid (CSF) concentration at the end of the infusion was 0.27 (+/- 0.1) microM when no IT-MTX was given and correlated with total steady-state (24-hr) serum concentration of MTX. By stepwise regression, the CSF MTX concentration correlated better with the nonprotein bound (free) steady-state serum MTX concentration (r = 0.66, P less than 0.01) than with total steady-state serum MTX concentration. Mean CSF: serum MTX concentration ratio was 0.023 (+/- 0.04) when no IT MTX was given. When an IT MTX dose (12 mg/m2) was given at the start of the MTX infusion, the steady-state CSF MTX concentration was 1.1 (+/- 0.4) microM, leading to a mean CSF: serum ratio of 0.073 (+/- 0.05). Despite 7-hydroxy-MTX serum concentrations exceeding MTX concentrations immediately after infusion, 7-hydroxy-MTX was not detectable in CSF of most patients (21 of 29), and was less than 50% of the concurrent MTX concentration when detectable. These data establish the substantial interpatient variability in CSF distribution of MTX after intermediate-dose MTX infusions and establish a significant correlation between steady-state free concentration of MTX in serum and CSF MTX concentration.     

Pharmacokinetic modeling of the anticonvulsant action of phenobarbital in rats

The aim of this study was to develop a model for the relationship between concentration and anticonvulsant effect of phenobarbital in the rat. The method of quantitating the anticonvulsant response on the basis of plasma pentylenetetrazol threshold concentrations, was optimized by application of a longitudinal study design. The pharmacokinetics of phenobarbital were studied in a separate set of rats (elimination half-life 11 +/- 2 hr). The anticonvulsant effect was measured 1 hr after i.v. administration. Concentration-effect relationships were assessed for serum (total and free), cerebrospinal fluid and brain concentrations on the basis of the sigmoid maximum effect model. The EC50 for total serum was 76 +/- 9 mg/l and for free serum, cerebrospinal fluid and brain 44 +/- 5, 43 +/- 7 and 50 +/- 8 mg/l and mg/kg, respectively (means +/- S.E.). The maximum effect was about 120 mg/l of pentylenetrazol. The respective EC50 ratios corresponded closely with the concentration ratios between the different compartments as determined by orthogonal regression analysis. For the greater part of the concentration range the concentration-effect relationship also could be fitted accurately to a simple linear model. Such relationships were not perturbed by the occurrence of seizures as these did not alter the distribution profile of phenobarbital. The pharmacokinetics and pharmacodynamics of p-hydroxyphenobarbital, the main metabolite of phenobarbital, also were investigated. This compound is eliminated very rapidly and has neither anticonvulsant activity of its own nor influences the anticonvulsant effect of phenobarbital at serum concentrations up to 30 mg/l. The described experimental strategies allow the study of factors influencing the concentration-anticonvulsant effect relationship of phenobarbital.     

Serum and sputum concentrations of netilmicin in combination with acylureidopenicillin and cephalosporins in clinical treatment of pulmonary exacerbations in cystic fibrosis

The pharmacokinetics of netilmicin was studied in 14 patients with cystic fibrosis, aged 4-21 years (mean 16 years) during treatment of pulmonary exacerbations of pseudomonas infection. The patients received 24 courses of netilmicin (10 mg/kg/day) in combination with azlocillin (600 mg/kg/day), cefsulodin (200 mg/kg/day) or ceftazidime (150 mg/kg/day) for 9-14 days. Seven patients received two or three courses of different combinations. Serum and sputum concentrations of netilmicin were determined on day 2 and 6. Mean (+/- S.E.M.) trough serum values were 1.4 +/- 0.2 mg/l (same on day 2 and 6), peak values at 10 min 13.6 +/- 1.0 and 13.7 +/- 0.9 mg/l, and serum concentration at 1 h 7.5 +/- 0.6 and 7.5 +/- 0.5 mg/l, on days 2 and 6 respectively. The half-life was about 1 h. The pharmacokinetics did not differ on day 2 and 6. Sputum concentrations increased up to 2-3 h after administration, mean (+/- S.E.M.) peak values being 2.6 +/- 0.6 and 1.5 +/- 0.4 mg/l at day 2 and 6, respectively. The study shows that the pharmacokinetics of netilmicin was not influenced by different combinations with beta-lactams. All patients improved clinically, but pseudomonas growth was only reduced in nine courses. In one case transient resistance to netilmicin developed during the treatment. The clinical efficacy and tolerance were good and similar to those seen with combinations with other aminoglycosides.     

Concentrations of apolipoproteins B, C-I, C-II, C-III and E in sera from normal men and their relation to serum lipoprotein levels

The concentrations of apolipoproteins B, C-I, C-II, C-III and E (by enzyme immunoassay), and cholesterol, triglycerides and phospholipids both in while serum and in serum very low (VLDL), low (LDL) and high (HDL) density lipoproteins, HDL2 and HDL3, were determined in sera from 29 randomly selected normolipidemic men, age 40-60 years, in Stockholm, Mean values, +/- SD, were for, apolipoprotein B, 720 +/- 162; C-I, 63 +/- 14; C-II, 27 +/- 11; C-III, 125 +/- 57; and for E, 25 +/- 6 mg/l. A skewness to the right of the distributions was found for apolipoproteins B and C-II and for serum triglycerides and VLDL lipids. The relations between the different variables were studied by linear correlation analysis. Several significant correlations existed between the lipoprotein levels. Apolipoprotein C-I, C-II and C-III were significantly correlated with each other, whereas neither apolipoprotein B nor apolipoprotein E was correlated with any other apolipoprotein. The following significant, positive correlations existed between the apolipoproteins and total serum lipids and/or lipids of lipoprotein density classes: apolipoprotein B with serum cholesterol and LDL lipids, apolipoprotein C-I with HDL3 cholesterol, apolipoprotein C-II with serum triglycerides and VLDL lipids, apolipoprotein C-III with serum cholesterol and phospholipids. Apolipoprotein E showed no correlation with either serum lipids or lipoproteins.     

VLDL apolipoprotein B determination in blood serum following precipitation of LDL with polyvinylsulphate

A method is described for the determination of VLDL apolipoprotein B by radial immunodiffusion (RID) in serum supernatants following precipitation of LDL with polyvinylsulphate. The measurement of VLDL apolipoprotein B is based on the incubation of the polyvinylsulphate supernatant with triglyceride lipase (330 kU/l end concentration) for 12-24 hours at 37 degrees C. A good measure of agreement was found for the corresponding VLDL apolipoprotein B values measured by RID in the polyvinylsulphate supernatants (y) and VLDL apolipoprotein B values calculated as tetramethylurea-insoluble protein in the d less than 1.006 kg/l serum fraction (x) (r = 0.88, y = 0.96x + 0.004, n = 54). Within the tested range of 1.2 mmol/l to 6.7 mmol/l triglycerides, the concentration of apolipoprotein B measured in the polyvinylsulphate supernatant showed a linear relationship. Correlation analysis of VLDL apolipoprotein B values and serum triglycerides and VLDL cholesterol, respectively, showed a good correlation (r = 0.77 and r = 0.75, respectively, n = 54). In the determination of VLDL apolipoprotein B measured in polyvinylsulphate supernatant, a variation coefficient of 4.3% (means = 10.1 mmol/l, n = 20) was found in relation to the precision in the series, and a variation coefficient of 11.4% (means = 5.3 mmol/l, n = 15) in relation to day to day precision.     

Kinetics of drug action in disease states. XVI. Pharmacodynamics of theophylline-induced seizures in rats

Seizures, often with fatal outcome, are a manifestation of pronounced theophylline intoxication. The purpose of this investigation was to characterize the relationship between theophylline concentrations and theophylline-induced convulsions and to develop an animal model suitable for exploring conditions that might predispose theophylline-treated individuals to seizures. Female Lewis rats (approximately 170 g) received an i.v. infusion of theophylline (as aminophylline) at one of three different rates (1.03-5.1 mg/min/rat) until the animals exhibited a maximal seizure (which occurred after 11 +/- 1 to 42 +/- 3 min of infusion). The total dose, the serum concentration (both total and unbound drug) and the brain concentration of theophylline at onset of seizures increased with increasing infusion rate. The theophylline concentration in cerebrospinal fluid at onset of seizures (mean +/- S.D., 232 +/- 17 mg/l, n = 41) was not affected by the infusion rate. The theophylline metabolites 1-methyluric acid and 1,3-dimethyluric acid were found in serum but at very much lower concentrations than those of theophylline. 1-Methylxanthine and caffeine were not detected in any serum sample, 3-methylxanthine was present in low concentrations in only some serum samples and 1-methyluric acid and 3-methylxanthine were found in the brain in low concentrations (less than 10 mg/kg). Theophylline metabolites were not detected in cerebrospinal fluid. Direct i.v. infusion of either 1-methyluric acid, 1,3-dimethyluric acid or 3-methylxanthine did not produce seizures despite high concentrations in serum. Ethylenediamine infusions also did not cause seizures.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reference intervals for serum apolipoproteins A-I, A-II, B, C-II, C-III, and E in healthy Japanese determined with a commercial immunoturbidimetric assay and effects of sex, age, smoking, drinking, and Lp(a) level

BACKGROUND: Apolipoproteins, which are contained in lipoprotein particles, play important roles in the transport of lipids. METHODS: Serum levels of apolipoproteins (apo) A-I, A-II, B, C-II, C-III, and E were determined by immunoturbidimetry in a healthy Japanese study population (1018 men and 1167 women, age 20-69 years) to establish reference intervals. RESULTS: Among the 2185 subjects examined, the mean serum value for apoA-I was 1.42 +/- 0.20 g/l, for apoA-II was 0.30 +/- 0.05 g/l, for apoB was 0.87 +/- 0.18 g/l, for apoC-II was 29 +/- 13 mg/l, for apoC-III was 75 +/- 20 mg/l, and for apoE was 36 +/- 9 mg/l. A sex difference was detected in the mean serum concentrations of all six apolipoproteins. Alcohol consumption and cigarette use had a slight effect on serum apolipoprotein concentrations. Age effects were observed among women in apoB, apoC-II, and apoC-III concentrations. Moreover, individuals with elevated serum lipoprotein (a) [Lp(a), >300 mg/l] also displayed increased serum apoB and apoC-II levels and an increased apoB/apoA-I ratio. CONCLUSION: The reference intervals for apolipoproteins in Japanese adults that we established, using commercially available reagents for automated analyzers, will be helpful for assessing risk of coronary heart disease and pathological conditions of patients with hyperlipidemia. We recommend use of these reference intervals for the clinical interpretation of serum apolipoprotein concentrations.     

Ceftriaxone kinetics and cerebrospinal fluid penetration in infants and children with meningitis

20 patients (0.4-5.6 years old) receiving ceftriaxone for the treatment of bacterial meningitis were studied. Simultaneous serum and cerebrospinal fluid concentrations of ceftriaxone were determined by HPLC in 15 patients at 11.4-12.8 h after an intravenous loading dose of 75 mg/kg. Serum and cerebrospinal fluid concentrations ranged from 20.5 to 44.9 (31.3 +/- 7.8) and from 1.1 to 8.0 (3.7 +/- 1.8) micrograms/ml, respectively. Cerebrospinal fluid concentrations ranged from 3 to 25% (12 +/- 6%) of the simultaneous serum concentrations. In 6 patients, serum and cerebrospinal fluid concentrations were determined after maintenance doses of 50 mg/kg/12 h. Serum and cerebrospinal fluid concentrations ranged from 120 to 144 and 2.3-4.9 micrograms/ml at 1.8-5.5 h after the first maintenance dose in 2 patients; 74-139 and 5.7-7.9 micrograms/ml at 1.3-5.8 h after the second dose in 3 patients and was 101 and 4.1 micrograms/ml at 4 h after the 3rd dose in 1 patient. Multiple blood samples were collected after the loading dose in 5 patients and after 9-10 days of maintenance doses in 3 patients. Steady-state peak and trough serum concentrations ranged from 295 to 440 and 32.6-44.8 micrograms/ml, respectively. After the loading and maintenance dose at steady-state, total body clearance averaged 1.17 and 0.64 ml/min (p = 0.01); apparent volume of distribution averaged 0.37 and 0.26 l/kg (p greater than 0.05); and elimination half-life averaged 3.7 and 4.6 h (p = 0.01), respectively. These results suggest that (1) adequate cerebrospinal fluid concentrations of ceftriaxone can be achieved in patients with meningitis with the dosage regimen studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of brodimoprim in serum and skin blister fluid

Following 400 mg brodimoprim given orally to 8 volunteers, the peaks of the mean concentration curves were 3.2 +/- 1.0 mg/l in serum and 1.0 +/- 0.2 mg/l (+/- SEM) in skin blister fluid. The terminal half-lives were 25.9 +/- 2.2 h and 42.2 +/- 6.5 h in serum and blister fluid, respectively. The area under the concentration-versus-time curve for blister fluid was 73% of serum value, and the mean recovery of bioactive drug in urine during 24 h was 3.4%. Considering the minimal inhibitory concentrations of potential target organisms and the slow elimination, the results suggest that brodimoprim may be useful in the treatment of infections, and that dosage once a day may be sufficient.     

Imipenem kinetics in serum, lung tissue and pericardial fluid in patients undergoing thoracotomy

Imipenem serum pharmacokinetics, lung tissue and pericardial fluid concentrations were measured in 10 patients undergoing thoracotomy, following a 1 g intravenous infusion of imipenem-cilastatin. The serum concentrations of imipenem 0.5 h and 4 h after the end of the 40 min infusion were 53.3 (+/- 16.7) and 2.0 (+/- 0.3) mg/l, respectively. The concentration of imipenem in lung tissue at 1 h was lower than in pericardial fluid and at 2.25 h the mean concentration of imipenem in pericardial fluid was 10.5 mg/l, vs. 0.28 mg/kg of lung tissue. Imipenem concentrations in pericardial fluid remained above 5 mg/l, well above the MIC for most pathogens, for 1 h whereas in pericardial fluid the concentration was 10.5 mg/l at 2.25 h.     

Measurement of vitamin D-binding protein in pleural fluids and sera by means of a turbidimetric immunoassay measuring system

BACKGROUND: Vitamin D-binding protein (DBP) has been recognized as a multifunctional plasma protein that can modulate certain immune and inflammatory responses. There may be differences between the DBP concentrations in pleural fluids from various diseases involving a variety of possible responses in the pleural cavity. METHODS: An anti-DBP polyclonal antibody was prepared using commercially available DBP to establish a quantitative measuring system for DBP. With a rabbit antibody, a turbidimetric immunoassay (TIA) was developed for DBP with an automatic analyzer. Using this measuring system, the concentrations of DBP were compared with the protein concentration in pleural fluid and serum specimens from patients with various diseases. RESULTS: The fluid DBP concentrations in transudative (n=11) and exudative (n=41) effusions were 71.9+/-21.2 and 180.7+/-43.7 mg/l, respectively. Among the exudative effusions, the fluid DBP concentrations in the bacterial (n=10), tuberculous (n=13), and malignant (n=18) effusions were 218.8+/-37.3, 186.7+/-26.2, and 155.1+/-41.3 mg/l, respectively. The DBP fluid/serum ratio and the fluid DBP/protein ratio in bacterial effusions were significantly higher than those in tuberculous (p<0.005, p<0.05, respectively) and malignant effusions (p<0.0005, p<0.005, respectively), although no statistically significant differences in the serum DBP/protein ratio between those effusions were found. CONCLUSIONS: Using the TIA assay, the DBP concentrations in bacterial pleural effusions were significantly higher than in tuberculous and malignant effusions.     

The penetration of ceftazidime into peritoneal fluid in patients undergoing elective abdominal surgery

Using paper discs we have made repeated observations during laparotomy in 31 patients after giving 1 g of ceftazidime intravenously. Samples of serum were obtained simultaneously. Rapid transfer of antibiotic occurred. Peak concentration in peritoneal fluid occurred within 10 minutes of injection (66.7 mg/l, S.E. +/- 10.6), the concurrent mean serum level being 106.0 mg/l (S.E. +/- 10.7). Thereafter levels in serum and peritoneal fluid fell roughly in parallel.     

Increased sensitivity to the anesthetic effect of phenobarbital in aging BN/BiRij rats.

The purpose of this study was to determine the influence of age on the pharmacokinetic/pharmacodynamic relationship of phenobarbital in male BN/BiRij rats aged 4, 15, 26, 31 and 36 months. The pharmacokinetics were studied on basis of the plasma concentration vs. time profile and the excretion of phenobarbital and parahydroxyphenobarbital in urine and feces after an i.v. dose of 20 mg/kg. The pharmacodynamics were determined as the threshold dose and cerebrospinal fluid threshold concentration of phenobarbital for the onset of loss of righting reflex (as a measure of the anesthetic effect) during an i.v. infusion at a rate of 3 mg/min. The dose requirement for the anesthetic effect decreased with increasing age from 263 +/- 4 mg/kg (mean +/- S.E.M.) for the 4-month-old rats to 202 +/- 6 mg/kg for the 31-month-old rats. Only minor changes in the pharmacokinetic parameters, the metabolite profile and the distribution of phenobarbital between plasma (total and free), cerebrospinal fluid and brain tissue were observed. With respect to the pharmacodynamics, however, evidence for an increase in brain sensitivity was observed, as reflected in a decrease in the threshold cerebrospinal fluid concentration from 181 +/- 4 mg/l (mean +/- S.E.M.) at 4 months to 134 +/- 4 mg/l at 31 months. It is concluded that the decreased dose requirement of phenobarbital in elderly BN/BiRij rats is due to an increased brain sensitivity as a result of the aging process per se rather than detectable pathology.     

Lipoprotein(a) in the cerebrospinal fluid of neurological patients with blood-cerebrospinal fluid barrier dysfunction

BACKGROUND: Lipoprotein(a) [Lp(a)] is a recognized pathogenic particle in human plasma, but its presence in the cerebrospinal fluid and its possible role in the central nervous system have not been documented. We tested the hypothesis that apolipoprotein(a) [apo(a)], free or as a component of the Lp(a) particle, can cross the blood-cerebrospinal fluid barrier and be found in the cerebrospinal fluid of patients affected by neurologic pathologies. METHODS: We studied paired cerebrospinal fluid/serum samples from 77 patients with inflammatory (n=20) or noninflammatory (n=34) blood-cerebrospinal fluid barrier dysfunction and without blood-cerebrospinal fluid barrier dysfunction (n=23). We used ELISA to measure Lp(a) concentrations and Western blot and immunodetection to analyze apo(a) isoforms in native and reducing conditions. RESULTS: Entire Lp(a) with either small or large apo(a) isoforms was present in the cerebrospinal fluid of patients with blood-cerebrospinal fluid barrier dysfunction, regardless of its pathogenesis. Multiple linear regression analysis showed that both serum Lp(a) concentration (P=0.003) and cerebrospinal fluid/serum albumin ratio (P<0.001) were predictors of the Lp(a) concentration in cerebrospinal fluid. CONCLUSIONS: Our results demonstrate that Lp(a) can cross a dysfunctional blood-cerebrospinal fluid barrier. The unusual presence of Lp(a) in the cerebrospinal fluid could extend some of its known pathogenic effects to the central nervous system.     

Penetration of ciprofloxacin and ofloxacin into human allograft pancreatic juice

The penetration of ciprofloxacin (500 mg) and ofloxacin (400 mg) into pancreatic juice following a single oral dose, was investigated in seven patients who had undergone pancreatic transplantation. With a special technique for segmental pancreatic transplantation it was possible to collect pure pancreatic juice at regular intervals for up to 24 h after drug intake. The antibiotic concentrations were determined by the agar-well diffusion method. The concentration of ciprofloxacin in pancreatic juice was 36% of that in serum. The same figure for ofloxacin was 92%. The mean peak level in pancreatic juice was 0.5 +/- 0.0 mg/l (+/- S.E.) for ciprofloxacin and occurred at 4 h after drug intake. The same figure for ofloxacin was 2.7 +/- 0.7 mg/l (+/- S.E.) occurring at 3.6 h. The decrease in concentrations with time was parallel to the serum concentration curves for both antibiotics. The concentrations of ofloxacin in pancreatic juice exceeded the MIC values for most of the organisms causing infections in the pancreas for several hours after an oral dose. The concentrations of ciprofloxacin only briefly exceeded the MIC for the same organisms.     

High-density lipoprotein apolipoproteins in urine: II. Enzyme-linked immunoassay of apolipoprotein A-I

We have developed a capture antibody, noncompetitive, enzyme-linked immunoassay for urinary apolipoprotein A-I (Apo A-I) in urine, with use of affinity-purified polyclonal antisera against Apo A-I. A 96-well microtiter plate format is used, with unconcentrated urine as sample and dilutions of serum or high-density lipoprotein (HDL) as standards. The intra- and interassay variation (CV) averaged 7.4% and 9.4%, respectively. The limit of detection is low (1.25 ng/L), and no cross-reactivity with Apo B, C, E, or A-II was detected. The mean (+/- SD) concentrations of Apo A-I in urine of patients with glomerular proteinuria were a thousandfold greater (38.4 +/- 23.1 mg/L) than in normal subjects (16.3 +/- 11.3 micrograms/L in men, 17.97 +/- 7.7 micrograms/L in women, a significant difference, P less than 0.001). Apo A-I measurements correlated very well (r = 0.92) with selectivity index assessment. The diurnal variation of the concentration of Apo A-I in urine appears to result from dilution related to fluid intake. This enzymatic method is easy to perform, can be used with large numbers of samples, and is adaptable for use in the routine clinical laboratory. The method holds promise for discriminating between normal and subclinical kidney disease populations by measuring the concentrations of urinary Apo A-I excreted on HDL particles.     

Quantification of human apolipoprotein E in plasma and lipoprotein subfractions by a non-competitive enzyme immunoassay

A non-competitive enzyme linked immunosorbent assay (ELISA) has been developed to quantitate apolipoprotein E (Apo E) concentrations in serum and in isolated lipoproteins. Microtiter plates coated with affinity-purified antibodies to Apo E were used and the Apo E bound to the plates was estimated with peroxidase-labelled antibodies to Apo E. The average concentration of Apo E in the serum from normolipidemic subjects (n = 132) was 54 +/- 19 mg/l. The within and between assay coefficients of variation were 4.65 and 7.08%, respectively. The standard curves for Apo E in serum, in VLDL and in HDL were parallel. There was a good correlation (r = 0.81) between estimation of Apo E by our assay and that by electroimmunoassay. Assay sensitivity (1 ng of Apo E) was sufficient to enable a study of the distribution of Apo E in plasma lipoproteins separated by density gradient ultracentrifugal fractionation.