PART I. THE DEVELOPMENT OF ANTIBODIES TO AFLATOXIN B1 USING BOVINE SERUM ALBUMIN AS A LIGAND. PART II. THE DEPOSITION OF INTRAVAGINALLY APPLIED POLYVINYLPYRROLIDONE-IODINE.
Abstract
Aflatoxins, produced by the mold Aspergillus flavus, are potent heptatocarcinogens. The compounds have been demonstrated to be a potential hazard to the human food supply. Current methods for aflatoxin detection and estimation are time consuming, are subject to numerous sources of error and interferences and lack the sensitivity to detect aflatoxins at suspected carcinogenic levels. Radioimmunoassay has been proposed as a method of quantitative aflatoxin analysis which could overcome some of these difficulties. The study dealt with the production of antisera to aflatoxin B1 which could potentially be used in a radioimmunoassay procedure for aflatoxin. New Zealand white rabbits were immunized by multiple subcutaneous injections at the nape of the neck with an emulsion of an aflatoxin B1-bovine serum albumin conjugate and Freund's adjuvant. Each of the rabbits received a different antigenic dose. The antigenic doses used for the initial injections ranged from 1.25 mg. to 6.25 mg of the conjugate. The immunization procedure was conducted over a period of 10 weeks. The titre of the antisera was determined at weeks 6, 8 and 10 of the immunization period. The titre was defined to be the serum dilution which would bind 50% of the aflatoxin B1 present in a challenge solution of aflatoxin B1. The maximum titre observed was 1:10. The 1:10 titre was observed in antisera obtained at week 10 from the rabbit which received the highest antigenic dose. A titre of less than 1:20 has been considered impractical for radioimmunoassay procedures. Antisera with such low titre could only be used for a minimal amount of assays and have been reported to lack the sensitivity and specificity desired for radioimmunoassay procedures. The low titre was attributed to either an insufficient antigen dose, inadequate time for maximum immunological response to occur or a lack of immunological response by the animals. Part II. Povidone-iodine has been extensively used as a germicide in surgical procedures and for the treatment of burns, vaginal infections and urinary tract infections. In recent years, side effects from the use of povidone-iodine such as elevated serum protein bound iodine levels, suppression of thyroid hormone synthesis, nephrotoxicity and acidosis and genetic effects have been reported. Povidone-iodine is a complex of polyvinylpyrrolidone (PVP) and iodine. The cause of the side effects reportedly result from either the absorption of PVP-I or iodine. The absorption and subsequent fate of PVP has been shown to be dependent on the compound's average molecular weight. High molecular weight PVP has been shown to be retained in the reticuloendothial system whereas low molecular weight PVP has been shown to be excreted rapidly via the kidneys. The study investigated the absorption, distribution and excretion of intravaginally applied solutions of PVP-I complex as influenced by the molecular weight of the PVP used in the synthesis of the complex. Eighteen New Zealand white rabbits were douched for 7 consecutive days with solutions of PVP-('131)I complex which had been synthesized from PVP with different average molecular weights. Three PVP-('131)I complex solutions were synthesized which contained 1% available iodine and 10% PVP. The solutions were synthesized from PVP-60, PVP-40 and PVP-10. The molecular weight of the PVP used to synthesize a solution of PVP-('131)I complex was not observed to influence the organ distribution or whole body absorption of ('131)I. The thyroid concentrated ('131)I to a significantly greater degree than did the ovary, fat, spleen, muscle, heart, kidney, liver, lung, uterus or blood of the rabbits. The treatment regime was not observed to result in an increase in serum protein bound iodine levels. The ('131)I activity was excreted primarily into the urine.
Degree
Ph.D.
Subject Area
Environmental science
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