M Mi it to oc ch ho on nd dr ri ia a a ac ct t a as s a a r re es se er rv vo oi ir r f fo or r t th he e b ba as si ic c a am mi in neIn the present study, we measured HIPDM lung kinetics and subcellular distribution in rabbits given i.v. 125 I-HIPDM. Rabbits were killed from 2 min to 5 h after injection, and the radioactivity retained in their lungs was measured. Subcellular lung fractions (nuclear, mitochondrial, lysosomal, microsomal, and postmicrosomal supernatant) were assayed for HIPDM radioactivity, protein content, and distribution of specific marker enzymes.HIPDM lung clearance in rabbits was nearly identical to that of humans. Virtually all the HIPDM radioactivity in lungs (98±1%) was associated with subcellular membranous structures. The highest HIPDM specific radioactivity was found in the mitochondrial fraction, and the subcellular distribution profile closely resembled that of the mitochondrial marker enzyme succinate cytochrome c reductase. No redistribution of HIPDM among subcellular compartments was observed over a 5 h period after injection.The data indicate that mitochondria act as reservoir for HIPDM in the lungs and contribute to the pulmonary persistence of this compound. HIPDM can be used to investigate the pulmonary uptake of basic amines in health and in lung disease.
Background:
Helicobacter pylori has attracted increasing attention among gastroenterologists because of its pathogenic potential, stimulating the search for non‐invasive diagnostic tests.
Aims:
In this study the efficacy of a new enzyme immunoassay designed to detect H. pylori antigens in stools (HpSA) was evaluated before and after eradication therapy.
Methods:
HpSA was performed on stool samples collected from 268 patients whose H. pylori status was defined on the basis of concordant results for the 13C‐urea breath test, rapid urease test and histology. The H. pylori‐positive patients were treated with a 1‐week triple therapy to eradicate the infection. One (T30) and 3 months (T90) after the end of therapy, 13C‐urea breath test and HpSA were repeated in the treated patients.
Results:
The overall diagnostic accuracy of HpSA at T30 (83%, 95% confidence interval (CI) 77–89%) was significantly lower in comparison to the values obtained at baseline (94%, 95% CI: 91–97%) and at T90 (97%, 95% CI: 94–99%). No significant difference was found between the diagnostic accuracy of HpSA at baseline and at T90 (P=0.253).
Conclusions:
The present data suggest that HpSA provides a low diagnostic accuracy when used shortly after treatment. It needs a longer period of follow‐up (8–12 weeks) to reach a reliability comparable to the 13C‐urea breath test.
We describe the optimization and validation of a clinically feasible radioreceptor assay to detect endogenous digitalis-like factor(s) (EDLF) in human plasma and urine. The assay is based on the competitive replacement of 125I-labeled digoxin on human placenta membranes by ligands present in sample extracts. Digoxin and ouabain were used as calibrators. We also describe simple and effective methods for extraction and enrichment of EDLF from human plasma and urine. Assay sensitivity and precision were enhanced by using a sequential saturation technique with appropriate concentrations of tracer and receptors. Filtration was used to separate bound from free ligand. A two-step solid-state extraction with acetonitrile allowed the separation of two EDLFs with different polarity (EDLF-1 and EDLF-2) from the same plasma sample. A one-step solid-state extraction with methanol was suitable for urine. EDLF-1 and EDLF-2 in healthy adults were respectively 204 +/- 155 and 207 +/- 423 pmol/L ouabain equivalents, or 312 +/- 241 and 302 +/- 581 pmol/L digoxin equivalents. Plasma concentrations of EDLFs in newborns and pregnant women were higher than in healthy adults, and the concentrations in urine were higher than in plasma. Several cross-reactivity experiments showed that physiological concentrations of endogenous steroids and lipids did not inhibit binding, and supported the hypothesis that EDLFs are endogenous compounds other than the steroids and lipids also investigated.
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