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F M Applehans

Publications and source records attributed to F M Applehans.

7 recordsLinked to original sources
PubMed1992

Intestinal fibrosis with partial obstruction in five horses and two ponies.

Fibrosis of the small intestine led to recurrent colic and weight loss in 2 ponies and 5 horses. There was a reduction in the length of the small intestine to one-half normal in horses 4 to 7. Histologic examination revealed substantial small intestinal submucosal fibrosis and arteriole sclerosis. The cause was not determined, but an environmental factor was suspected because 3 horses were from the same farm and the other animals were from within a 10-mile radius of the farm. The submucosal fibrosis appeared to be secondary to sclerosis of arterioles in the submucosa and mesentery, with low blood flow state or altered vessel permeability.

Abdominal Pain↗
PubMed1987

Structure-activity relationships of selected pyridines. III. Log Kow analysis.

Twenty 2- and 3-position derivatives of pyridine (C5H5N) were tested following a short-term static protocol. Biological activity was monitored as population growth of Tetrahymena pyriformis. These data were combined with previously reported data for twenty 4-position derivatives. Structure-activity relationships were examined using Kow as the physicochemical descriptor. These data form three linear models: one for the non-H-polar derivatives and two for the H-polar derivatives. The latter two models are parallel but have no obvious basis for a priori selectivity. HPLC analysis for toxicant persistence shows that only the smaller non-H-polar derivatives have any significant abiotic loss over the duration of the biological testing.

Animals↗
PubMed1987

Effects of zinc deficiency on thyroid function.

Interactive combinations of altered zinc and thyroid states were studied in rats to assess pathophysiologic effects. Clinical signs of zinc deficiency or thyroid alteration were limited to effects on growth rate. Changes in organ and glandular weights and serum thyrotropin levels reflected changes in serum thyroid hormone concentrations. Significantly (probability less than .001), zinc-deficient rats had enhanced hepatic thyroxine-5'-monodeiodinase activity. In addition, the zinc-deficient state was found to be protective against thiouracil-induced suppression of the microsomal-monooxygenase and thyroxine-5'-monodeiodinase enzyme complex. This protective effect was evident by greater thyroxine-5'-monodeiodinase and reduced nicotinamide-adenine dinucleotide phosphate cytochrome c reductase activities, as well as cytochrome P-450 content, in zinc-deficient/thiouracil-treated animals. Thus, the enzyme complex had increased triiodothyronine-generating capacity in conditions of zinc deficiency, which may be important because of the greater biological reactivity of triiodothyronine. Primary zinc deficiency conditions of the magnitude seen in this study and in this-age rat did not appear to alter serum thyroid hormone levels or organ/glandular function. However, concurrent zinc deficiency and altered thyroid status did change thyroid hormone response and disposition, which may be important to populations at risk because of thyroid dysfunctional states.

Animals↗
PubMed1985

Correlations for the acute toxicity of multiple nitrogen substituted aromatic molecules.

Twenty-nine compounds, including amino and nitro derivatives of aromatic hydrocarbons as well as azaarenes and indole analogs, were assayed. The biological activity was monitored as population growth to axenic cultures of the ciliate Tetrahymena pyriformis. Structure-activity relationships were examined by linear regression analysis of log biological activity (Y) and log 1-octanol/water partition coefficient (X). Partition coefficients were determined by linear regression analysis of the retention time index of HPLC data. Attempts to generate linear predictive correlations for all the test compounds (n = 29; r2 = 0.325; P greater than 0.0013) and groups, subdivided based on the following chemical classes: aromatic hydrocarbons (n = 13; r2 = 0.122; P greater than 0.2417), azaarenes (n = 9; r2 = 0.348; P greater than 0.0946) and indole analogs (n = 7; r2 = 0.743; P greater than 0.0126), met with little success. Similarly, subdivisions based on the presence of a single (n = 14; r2 = 0.514; P greater than 0.0039) or multiple H-polar groups, i.e., NO2, NH2 (n = 15; r2 = 0.195; P greater than 0.0996), met with little success also. However, if one segregates the compounds which have para oriented H-polar substituents one gets a strong linear predictive correlation (n = 11; r2 = 0.889; P greater than 0.0001). A subdivision of the remaining data set leads to two models (n = 11; r2 = 0.845; P greater than 0.0001) and (n = 7; r2 = 0.965; P greater than 0.0001). An examination of the toxicity partitioning product values suggests the three-line predictive correlation model of these data is valid.

Animals↗
PubMed1981

National study of chlorinated hydrocarbon insecticide residues in human milk, USA. I. Geographic distribution of dieldrin, heptachlor, heptachlor epoxide, chlordane, oxychlordane, and mirex.

Human milk samples obtained from 1436 women residing in the United States were analyzed by gas-liquid chromatography for the chlorinated hydrocarbon insecticides--dieldrin, chlordane, heptachlor, heptachlor epoxide, oxychlordane and Mirex. Dieldrin was found above the detection limit (1.0 ppb) in over 80% of all the samples collected. Chlordane was not found in any of the 1436 milk samples but its metabolite, oxychlordane, was found above the detection limit in 74% of the samples. Although heptachlor was recovered in less than 2% of the samples, its metabolite, heptachlor epoxide, was found above the detection limit in 63% of the samples. It was of considerable interest that Mirex was not positively identified in any of the samples. The proportion of samples with values above the detection limit for dieldrin, heptachlor epoxide and oxychlordane varied significantly among the five geographic regions with the southeastern United States having the highest mean residue level for each of these three contaminants. For the United States the mean fat adjusted residue levels of those samples above the detection limit were 164.2 ppb for dieldrin, 91.4 ppb for heptachlor epoxide, and 95.8 ppb for oxychlordane.

Adult↗