ABSTRACT
OBJECTIVE: To compare two quantitative pilocarpine iontophoresis tests for sweat chloride. DESIGN: Simultaneous right and left arm sweat tests were done with the Gibson/Cooke and the CF quantum technologies. SETTING: Sweat tests were performed in a quality controlled cystic fibrosis (CF) sweat test laboratory by an experienced technologist at the University of Minnesota CF Center. PATIENTS: Patients referred for sweat tests as well as volunteer CF and control subjects (50 CF and 114 'normals') were tested. INTERVENTIONS: Standard procedures were used for the Gibson/Cooke test (GCST). The manufacturer of the CF quantum test (CFQT) provided factory standardized materials. MAIN OUTCOME MEASURES: Sweat chloride concentration, test time, failed tests, sensitivity, specificity, and cost. RESULTS: Duplicate test comparing the CFQT and the GCST revealed good comparability (R2 = 0.9434). Sensitivity and specificity of the two methods are comparable at about 94% and 99% respectively. Rate of failed tests was 1% for the CFQT and 15% for the GCST. The CFQT and the GCST are comparable (R2 = 0.9434). Sensitivity (94%) and specificity (99%) are the same for both tests. CONCLUSIONS: The CFQT method is equal in accuracy and reliability to the more labor-intensive and costly GCST. Advantages of the CFQT are: the small sample size required (three to ten mg), decreased operator dependence, simpler to perform, and requires less equipment. It could be used in a clinic setting to diagnose CF in patients with suggestive symptoms.
Subject(s)
Chlorides/analysis , Cystic Fibrosis/diagnosis , Reagent Kits, Diagnostic , Sweat/chemistry , Adolescent , Adult , Aged , Child , Child, Preschool , Humans , Infant , Iontophoresis , Middle Aged , Pilocarpine/administration & dosage , Sensitivity and SpecificityABSTRACT
The preneoplastic skin changes usually induced by topical application of 7,12-dimethylbenz[a]anthracene (DMBA) to adult rat skin did not appear when animals were treated locally with depot im injections of high doses of retinyl palmitate (RP) prior to exposure to the carcinogen. The epidermal histology after RP-DMBA treatment was similar to that seen in areas exposed to RP alone. Keratinization was inhibited but there was no cellular atypia, evidence of cell injury, or mucous metaplasia. Other features were hyperplasia with acanthosis and thickened stratum granulosum, parakeratosis, intercellular edema, and loss of hair overlying the injection site. Ultrastructurally, the epidermal cells contained conspicuously fewer tonofibrils and increased dense chromatin, when compared to control cells. Skin changes observed following treatment of littermates with DMBA alone included the appearance of giant tumor cells, dyskeratotic cells, nuclear hyperchromatism, increased nucleocytoplasmic ratio, and pleomorphic nuclei and nucleoli. oss of desmosomes, increased tonofibrils, and defects in the basement membrane with epithelial projections into the dermis were also seen. These preneoplastic changes did not regress when application with DMBA was discontinued after 6 weeks; exposure to the carcinogen for longer than 6 weeks resulted in an exacerbation of the abnormal state. RP had profound effects on rat epidermis that interfered with the effects of a potent skin carcinogen. The mechanisms underlying the phenomenon have not been defined. The use of depot injections of the vitamin which avoids both systemic toxicity and the local irritation seen with topical exposure could serve as a model in which the anticarcinogenesis properties of retinoids could be explored.
Subject(s)
9,10-Dimethyl-1,2-benzanthracene/antagonists & inhibitors , Benz(a)Anthracenes/antagonists & inhibitors , Precancerous Conditions , Skin Neoplasms/chemically induced , Vitamin A/analogs & derivatives , 9,10-Dimethyl-1,2-benzanthracene/administration & dosage , Administration, Topical , Animals , Diterpenes , Drug Administration Schedule , Injections, Intramuscular , Male , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/pathology , Palmitates/administration & dosage , Palmitates/pharmacology , Precancerous Conditions/chemically induced , Precancerous Conditions/pathology , Rats , Retinyl Esters , Skin/drug effects , Skin Neoplasms/pathology , Vitamin A/administration & dosage , Vitamin A/pharmacologyABSTRACT
Consistent local dermal hypervitaminotic A effects without systemic toxicity were produced in male albino rats injected intramuscularly with high doses of vitamin A palmitate. There was a loss of hair overlying the site of injection, accumulation of UV-fluorescent fat droplets in dermal and hypodermal macrophages and in the stratum Malpighi, intercellular epidermal edema, thickening of the stratum Malpighi and thinning of the stratum corneum. Subcutaneous administration of the same dose of vitamin A palmitate or intramuscular injection of vitamin A alcohol did not produce any skin lesions although morphologic examination of liver specimens from all the vitamin-treated animals revealed storage of vitamin A. Accumulation of the vitamin in macrophages in the dermis was always seen in specimens of skin overlying the site of intramuscular injection of vitamn A palmitate, suggesting that the changes in epidermis may be due to sustained release from this local intracellular store. Application of this method of parenteral administration of the esterified form of the agent will facilitate its use in studies of promotion or inhibition of tumorigenesis and in disorders of keratinization.
