Effects of arsanilic acids on growth, serum enzymes, hematologic values, and residual arsenic in young swine.
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Humans are exposed to a number of toxic elements in the environment; however, most experiments with laboratory animals investigate only one toxic element. To determine if concomitant exposure to lead (Pb), cadmium (Cd), and/or arsenic (As) modified the changes produced by any one metal in various parameters of toxicity, 168 male, Sprague-Dawley, young adult rats were fed nutritionally adequate diets to which had been added 0 or 200 ppm Pb as Pb acetate, or 50 ppm Cd as Cd chloride, or 50 ppm As as sodium arsenate or arsanilic acid in a factorial design for a period of 10 weeks. At these concentrations, Cd and As reduced weight gain even when differences in food intake were taken into account; administration of both Cd and As depressed weight gain more than did either metal alone. Pb did not adversely affect food consumption or weight gain. Increased numbers of red blood cells (RBCs) were observed following administration of Pb, Cd, or As; usually more cells were observed when two or three metals were administered, compared to individual metals. Despite increasing numbers of circulating RBCs, hemoglobin and hematocrit were reduced, especially with the Pb-Cd combination and the Cd-arsanilic acid combination. Specific effects of Pb on heme synthesis were observed, including increased urinary excretion of delta-aminolevulinic acid; this increase was reduced by the presence of dietary cadmium. Analyses of blood showed values for the laboratory rat within normal ranges for blood urea nitrogen, creatinine, cholesterol, calcium, albumin, total protein, and bilirubin. Uric acid was increased by Pb, with little modification by dietary Cd or As content. Serum glutamate-oxalate transaminase activity was reduced by As. Serum alkaline phosphatase was greatly reduced by either As or Cd but not Pb. Combinations of As and Cd did not further reduce the activity of this enzyme. Kidney weight and kidney weight/body weight ratios were increased by Pb alone, with no effects of Cd or As alone or as interactions. Liver weight/body weight ratios were reduced in animals fed 50 ppm dietary Cd. Kidney histology shows predominantly Pb effects, namely, intranuclear inclusion bodies and cloudy swelling. Ultrastructural evaluation of kidneys from Pb-treated animals disclosed nuclear inclusion bodies of the usual morphology and mitochondrial swelling. Concurrent administration of Cd greatly minimized Pb effects on the kidney under conditions of this experiment. Liver histology suggests an increased rate of cell turnover with either As compound, but few specific changes.
The in vitro activities of 39 antimicrobial agents against 23 isolates of Treponema hyodysenteriae, the majority of which were field isolates, were determined by the agar dilution technique. Quinoxalines, pleuromutilin, nitroimidazoles, and nitrofuran were the most active. Their activities ranged from </=0.10 to 1.56 mug/ml. Lincomycin, penicillins, chloramphenicol, tetracyclines, cephalosporins, three peptides (virginiamycin, thiopeptin, and bacitracin), and one aminoglycoside (gentamicin) exhibited intermediate levels of activity ranging from 0.39 to 50 mug/ml. Four peptides (enduracidin, viomycin, bicyclomycin, and colistin), three aminoglycosides (kanamycin, streptomycin, and neomycin), polyene, and other agents, including novobiocin, vancomycin, rifampin, nalidixic acid, and p-arsanilic acid, displayed limited activities ranging from 12.5 to >/=100 mug/ml. Macrolides showed varying degrees of activity depending upon isolates.
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Mice of strain A/J responded to repeated intraperitoneal injection of Limulus hemocyanin derivatized with arsanilic acid by producing large quantities (approximately 5 mg/mL of ascites fluid) of IgG antibodies specific for this hapten. The antibodies possessed a characteristic idiotypic determinant and exhibited restricted heterogeneity as demonstrated by isoelectric focusing and primary N-terminal amino acid sequence analysis of isolated light and heavy polypeptide chains. Both light- and heavy-chain sequences were comparable to those of myeloma proteins in lack of heterogeneity. The N terminus of the light chain exhibited V KI sequence and only one position in the first 30 residues showed more than one amino acid. No variability was observed in the first 10 N-terminal residues of the heavy chain. Rabbit antiserum to the idiotype blocked binding of hapten by the purified antibody. The presence of both light- and heavy-chain antigenic determinants was required for optimal formation of the idiotypic determinant.
Eperythrozoonosis was diagnosed in 23 herds of swine. Icterus and anemia were the major diagnostic criteria, with low packed cell volumes confirming the clinical impression of anemia. Indirect hemagglutination titers provided an indirect measure of infection rates and appeared to correlate positively with severity of signs. Treatment with oxytetracycline and arsanilic acid controlled the disease, but only when combined with efforts to limit transmission of the causative organism through control of lice.
This investigation demonstrates the use of substitution-inert metal ions as site-specific amino acid modifying reagents. The approach involves the production of a chelating agent at the site of interest with the subsequent in situ oxidation of substitution-labile cobalt(II) to exchange-inert cobalt(III) with H2O2. We have produced the chelate complex ethylenediamine-N,N'-diacetato(arsanilazotyrosinato-248 carboxypeptidase A)cobalt(III) [CoIII(EDDA)(AA-CPA-Zn)]. Model CoIII(EDDA)(azophenolate) complexes have helped to define the reaction conditions necessary to produce the enzyme derivative and have proved invaluable in the spectral analysis of the cobalt(III)-enzyme complex. The modified enzyme contains one active-site zinc and one externally bound cobalt per enzyme monometer. Circular dichroism and visible spectra of the derivative and apoenzyme substantiate the site-specific nature of the incorporation. Concimitant with CoIIIEDDA incorporation, the enzyme loses its peptidase activity yet maintains with FeIIEDTA returns the original properties of the arsanilazotyrosine-248 enzyme.
Reaction of carboxypeptidase A crystals with diazotized arsanilic acid uniquely modifies Tyr-248 to form a monazo derivative, which-in solution-forms an intramolecular inner-sphere coordination complex in the active site zinc atom. tarsanilazocarboxypeptidase exhibits spectral properties that are closely similar to those of the model complex, tetrazolylazo-N-carbobenzoxytyrosine Zn2+, with a distinctive maximum at 510 nm. In addition, its circular dichroic spectrum reveals a negative extremum at this wavelength, also characteristic of this complex. Both spectra are exquisitely responsive to pth changes and serve to monitor formation and dissociation of the metal-azophenol complex. Two pKapp at 7.7 and 9.5 delineate the pH range over which the probe characteristics most effectively gauge conformational features of the active center of arsanilazcarboxypeptidase. Other environmental parameters, e.g., substrates and inhibitors, as well as crystallization of the enzyme also critically influence the formation and dissociation of the complex; the response of the probe suggests that they induce conformational movement of the azoTyr-248 residue away from the zinc atom. tthe now available chemical, functional, structural data bearing on the spatial relationships of Tyr-248 and Zn, both thought critical to catalysis, are evaluated, based on spectra of arsanilazo- and nitrocarboxypeptidase crystals and solutions as well as on detailed kinetic analyses of the native enzyme in both physical states and based on the X-ray structure analysis of the native enzyme and its Gly-L-Tyr complex. Collectively all of the data show that the conformation of carboxypeptidase in crystals differs from that in solution. Moreover, reexamination of the original X-ray maps reported in 1968 and thought to preclude a Tyr-248-Zn interaction now leads to the conclusion that in up to 25 per cent of the molecules in the crystals ttyr-248 interacts with the active site zinc atom (W.D. Lipscomb (1973), Proc. Nat. Acad. Sci U.S. 70, 3797). Thus, even in the crystals the enzyme exists in at least two different conformations. In one of these Tyr-248 is near while in the other it is far from the zinc atom. The spectral effects of Gly-L-Tyr and beta-phenylpropionate on solutions of arsanilazo- and of nitrocarboxypeptidase demonstrate that during the catalytic process Tyr-248 moves away from the zinc atom. This implies a mechanistic role for Tyr-248 different from that postulated on the basis of X-ray crystallographic analysis. Indeed, the proximity of ttyr-248 to the zinc atom, when altered by substrates and inhibitor, may reflect certain of the properties characteristic of the entatic, active site.
Eleven rat diets fortified with 200 ppm Pb as lead acetate, and/or 50 ppm Cd as cadmium chloride, and/or 50 ppm As as sodium arsenate or p-arsanilic acid for use in a feeding study to determine the interactive effects of the three elements in rats were analyzed to confirm the fortification levels. Gross inhomogeneity was found. After remixing, variability within and among diets was improved but was still unacceptable. Fortification levels of Pb and of As as sodium arsenate could be accurately determined only by taking a very large sample and homogenizing the diet subsamples with a Polytron homogenizer. A review of the recent literature indicates that no standard procedures exist for fortification, mixing, or analysis of animal feeding study diets. Such procedures should be developed and analysis of the diets before and at intervals during a feeding study should be adopted as standard procedure.
1. In order to obtain an effective ligand for affinity chromatography of the low molecular weight acid phosphatase (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.2) from human red cells nine phosphonic and two arsonic acid substrate analogues were investigated as potential inhibitors. The two forms of acid phosphatase type B (b1 and b2) were isolated and partially purified using conventional methods and the inhibitory action of the substrate analogs investigated. 2. Four of the phosphonic acids were relatively effective competitive inhibitors. It appears that certain structural and electronic requirements have to be fulfilled by the phosphonic acids in order to exhibit significant affinity for the enzyme. A high affinity appears to require the presence of a bulky, hydrophobic moiety which has to be separated from the phosphorus atom by the distance of one atom. 3. p-Aminobenzylphosphonic acid exerted the highest affinity for acid phosphatase with a pH optimum at 6.5. Ki values of 4 . 10(-4) and 6 . 10(-4) M were found for the b1 and b2 forms, respectively. 4. Coupling of p-aminobenzylphosphonic acid to Agarose yielded an effective and specific affinity medium. By means of affinity chromatography using this medium, acid phosphatase was purified 500-fold in a single step.
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Respiratory hypersensitivity to small chemical determinants (haptens) was produced in guinea pigs by repeatedly exposing the animals to aerosols of hapten-ovalbumin conjugates. In this way, reactivity toward p-azobenzenearsonate and p-tolyl isocyanate was induced. Carrier (ovalbumin)-specific respiratory reactions were not produced. Hapten-specific respiratory hypersensitivity was accompanied by the production of hapten-specific antibodies. The method for inducing hapten-specific hypersensitivity can be applied to screen various industrial chemicals for their sensitizing abilities toward the respiratory tract.
it was shown in our previous paper that mice primed with chemically modified bacterial alpha-amylase (BaA), which was neither cross-reactive with anti-BaA antibody nor able to induce a humoral anti-BaA response, developed enhanced responses to a subsequent challenge with native BaA and that the magnitude of the immunological memory was closely related to the priming dose of modified BaA. This paper describes the experimental conditions for induction of delayed hypersensitivity (DH) by modified BaA in relation to the development of immunological memory for antibody response to native BaA. Mice primed with either an intraperitoneal (i.p.) or subcutaneous (s.c.) injection of modified BaA in complete Freunds adjuvant (CFA) developed enhanced anti-BaA as the immunogen and modified BaA as the eliciting antigen, the relationship of anti-BaA responses to a subsequent challenge with BaA. In contrast, when mice were immunized with an s.c. injection of the modified BaA only, a significant level of DH to native BaA could be induced, as measured by the footpad reaction (FPR). The highest degree of DH was observed in mice given 50 micrograms of modified BaA. DH was detectable within 5 days and persisted for 25 days after immunization. In the reciprocal combination of native BaA as the immunogen and modified BaA as the eliciting antigen, the relationship of anti-BaA responses to DH was examined. The primary anti-BaA responses induced by an i.p. injection of large doses of BaA was markedly higher than those induced by an s.c. injection, while DH was exhibited only in mice given s.c. injection of BaA in CFA. With respect to DH to native BaA induced by the modified BaA, it was shown that C3H/He mice were high and C57BL/6 mice were low responders.
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Mice tolerized by low doses of bovine IgG (BGG), immunized with arsanilated (ARS) conjugates and challenged with ARS-BGG show an augmented anti-BGG antibody response compared with controls immunized with nonconjugated carrier. Conditions optimal for generating hapten help are explored and suggest that the phenomenon is mediated by hapten-specific helper T cells. During exploration of these conditions it became apparent that the response was suppression rather than augmentation with ARS, under certain circumstances, and with 2,4-dinitrophenyl, 4-hydroxy-5-iodo-3-nitro-phenylacetyl (NIP) and sulfanilic acid, under all conditions tested. Especially important in determining the outcome of the interaction was the type of adjuvant used for hapten priming. The significance of these observations is discussed in relationship to the balance between negative and positive cooperation.
The trypsin and chymotrypsin inhibitor from chick peas (CI) is stable in HCl 0.001 M -- 0.01 M and in KOH 0.01 M -- 0.05 M even after 24 h. Increased KOH concentrations decrease considerably the inhibitory activity already after 1 h. Maleyation and succinylation of the inhibitor resulted in almost full loss of its trypsin-inhibitory activity but had no effect on the chymotrypsin-inhibitory activity. A series of modifications directed towards tyrosyl residues showed that iodination influenced only the chymotrypsin-inhibitory activity; however, nitration and arsanilation affected not only the chymotrypsin-inhibitory activity but also the trypsin-inhibitory activity. Treatment of the inhibitor with CNBr and chloramine T resulted only in a decrease in the chymotrypsin-inhibitory activity indicating that the only methionine is involved in the chymotrypsin-inhibitory activity. When CI-fragment A, previously treated with trypsin at pH 3.75, was further treated with carboxypeptidase B, a release of three lysyl residues per mole protein was found. CI was separated by equilibrium chromatography on SP-Sephadex column into two isoinhibitors, CII and CIII, respectively. Both inhibited trypsin and chymotrypsin with the same specific activity as CI. They differed from each other only in a glutamyl, aspartyl, glycyl and alanyl residue.