The synthetic chemical 4-aminobiphenyl (4-ABP) has been shown to be a bladder carcinogen in both man and animals. A valid radioimmunoassay for a metabolite of 4-ABP has been developed as a means to monitor potential human exposure to 4-ABP. The antibody was produced by the immunization of two female New Zealand White rabbits and was found to be highly specific for 4-acetamidobiphenyl (4-AABP), the acetylated metabolite of 4-ABP. At an initial dilution of 1/5000, the antisera bound 45% of the [125I]-labeled derivative of 4-ABP. This derivative was prepared by coupling 4-hemisuccinamidobiphenyl (4-HSBP) with tyramine, and then radioiodinating this compound using the enzymatic lactoperoxidase method. The dose of 4-acetamidobiphenyl which would displace 50% of the labeled hapten initially bound to the antiserum, was about 1 ng (4.8 pmol). Scatchard analysis of the standard curve binding data indicated the presence of at least two populations of binding sites. The equilibrium association constant for the higher binding affinity component was 2.8 x 10(8) Liters/mole. A series of 210 randomly selected human urine control samples were analyzed and a nonspecific background contribution of 1.67 +/- 0.07 ng (mean + S.E.) of "4-acetamidobiphenyl"/mL urine was found.

Aminobiphenyl Compounds↗

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Validation of a radioimmunoassay procedure for N,N'-diacetylbenzidine, a metabolite of the chemical carcinogen benzidine, in urine.

The biaryl amine benzidine has been reported to produce tumors of the bladder in both man and animals. We have developed and validated a radioimmunoassay (RIA) procedure for monitoring potential human exposure to benzidine through detection in urine samples of one of its known urinary metabolites. The antibody used in the assay was produced in rabbits and is specific for N,N'-diacetylbenzidine (N,N'-DAB). At a 1/15000 initial dilution, this antiserum bound 50% of an iodinated tracer [125I]-N4'-[4-hydroxyphenethylaminohemisuccinyl]-4-acetamido-4-aminobiphenyl. One hundred pg (0.373 pmol) of N,N'-DAB displaced 50% of the tracer initially bound to the antiserum. The validity of the RIA procedure was established by the parallelism exhibited between the standard curve and aliquots of spiked human urine samples. The RIA has good spiked human urine samples. The RIA has good sensitivity (average minimal detectable dose less than 10 pg) and reproducibility (within-and between-assay coefficients of variation at midrange of the standard curve were 3.94 and 12.48, respectively). A series of 109 randomly selected human urine control samples were analyzed and a nonspecific interference of 0.52 +/- 0.04 ng of N,N'-DAB/mL urine was found.

Animals↗

PubMedDate not supplied

Use of amino acid clamps to investigate the role of insulin in regulating protein breakdown in vivo.

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Alanine↗

PubMedDate not supplied

Adding, defining and measuring value.

Suppliers to the health care industry are changing relationships with their customers by forging partnerships that blur the boundaries between them. Here, representatives from several suppliers discuss what programs and services the market has driven them to offer.

Consultants↗

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Nurses: the saga continues.

Some nurses are claiming that patient-focused work redesign models sacrifice quality of care for cost efficiency. While they have some valid concerns, others see legitimate reasons for using unlicensed assistive personnel at the bedside as the role of nursing changes within hospitals.

Cost Control↗

PubMedDate not supplied

Efficacy and safety of constant-rate intravenous cyclosporine infusion immediately after heart transplantation.

Oral cyclosporine therapy immediately after heart transplantation is erratic and difficult to predict. The purpose of this study was to evaluate the relative efficacy and safety of cyclosporine when administered by constant-rate infusion immediately after transplantation. Nineteen patients (17 men and two women) aged 50 years (range 25 to 61 years) who weighed 71 +/- 9 kg, participated in the study and received cyclosporine, 7 to 10 mg/hr (117 +/- 15 micrograms/kg/hr). The infusions were initially maintained for 26 +/- 5 hours (range 18 to 42 hours) without adjustments in dosage. Whole blood samples were obtained at hourly intervals for the first 8 to 12 hours and then daily throughout the 7-day study period and were analyzed by high-performance liquid chromatography. Constant-rate cyclosporine infusion resulted in therapeutic blood levels (350 to 450 ng/ml) at 6 hours. These levels remained relatively steady throughout the 7-day infusion, requiring only minimal dosage adjustments. Kidney function was not altered significantly after 7 days of intravenous cyclosporine therapy as evidenced by a mean serum creatinine level of 1.3 mg/dl before therapy and 1.4 mg/dl after therapy. There, however, was a transient rise in serum creatinine level in most patients on the second or third day after transplantation that resolved without a reduction in cyclosporine dosage. The mean endomyocardial biopsy score at 1 week after transplantation was 0.1, and only four of the patients required additional immunosuppressive therapy to treat rejection during the first 6 weeks after transplantation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

Effect of inline filtration on postinfusion phlebitis.

The effect of inline i.v. filters on postinfusion phlebitis (PIP) and bacterial colonization of i.v. catheters was evaluated. The subjects of the prospective double-blind study were 195 men undergoing elective surgery. Polyethylene i.v. catheters of varying sizes were inserted the morning of surgery. Before catheterization, each site was shaved and cleansed with 1% povidone-iodine solution. In the experimental group, all i.v. fluids, additives, and medications were administered through a 0.22-micron micropore inline final filter. In the control group, no membrane filter was present in the filter housing. Drug and fluid therapy were determined by the physician, and flow rates were maintained at 40 ml/hr if not specified. Every 12 hours, sites were inspected and observations were graded according to criteria adapted from an earlier study. The incidence of phlebitis in the two groups was compared. At the termination of i.v. therapy, catheters were removed and cultured. The incidence of PIP in the experimental group (38/95) and the control group (39/100) was not significantly different. There were no differences between groups in variables possibly related to the occurrence of PIP, such as patient age, i.v. flow rate, catheter size, and use of potassium chloride i.v. additive. Of 141 i.v. catheters that were cultured, 25 yielded 10 or more colonies per plate; 21 were coagulase-negative staphylococci. Positive cultures occurred as frequently in patients without filters as in those with filters. No patient had clinical evidence of bacteremia. In these general surgical patients, inline filters did not affect the incidence of PIP or bacterial colonization of i.v. catheters. While the use of inline filters to prevent infusion of microorganisms deserves consideration, their routine use as a means of reducing PIP is unwarranted.

Adult↗