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Biomedical subjects

E E Storrs

Publications and source records attributed to E E Storrs.

At least 19 recordsLinked to original sources

Antibodies to St. Louis encephalitis virus in armadillos from southern Florida.

From January 1990 through March 1991, 189 armadillos (Dasypus novemcinctus) were collected from Brevard and Glades Counties in southern Florida (USA). The sera were analyzed for hemagglutination-inhibition (HAI) antibodies against St. Louis encephalitis (SLE) and eastern equine encephalomyelitis (EEE) viruses. None of the armadillos had detectable HAI antibody to EEE virus, but 59 (31%) had antibodies against SLE virus. Sera from 31 of the HAI-positive armadillos contained significant levels of neutralizing (NT) antibody to SLE virus. Armadillos captured during the 1990 SLE human epidemic in south Florida had a greater prevalence of HAI and NT antibody to SLE virus than did animals captured before the start of the epidemic. This is evidence that armadillos were fed on by mosquitoes infected with SLE virus. We propose that armadillos may be involved in the SLE amplification and transmission cycles in Florida.

Animals

Isolation of cultivable mycobacteria from feces and lungs of armadillos infected with Mycobacterium leprae.

In the past, no cultivable mycobacteria were isolated from armadillos captured in the state of Florida, U.S.A. But recent findings of acid-fast bacilli (AFB) in the lungs of armadillos infected with Mycobacterium leprae prompted us to undertake this study to determine the correlation between systemic leprosy infection and the occurrence of cultivable mycobacteria in the lungs and stools of these animals. No AFB could be isolated from noninfected animals. Seventy percent of the infected animals developed disseminated infection, but no cultivable mycobacteria were isolated from their livers and spleens. However, cultivable mycobacteria were isolated from the lungs and stools of a large number of armadillos showing disseminated infection. The most common among these were M. gordonae, M. fortuitum, and M. avium. There was a close correlation between the development of disseminated leprosy infection and the occurrence of cultivable mycobacteria in their lungs and stools, perhaps due to the decline in the immune system in these animals in the later stages of infection.

Animals

Plasma and erythrocyte cholinesterase values for the common long-nosed armadillo, Dasypus novemcinctus.

Plasma and erythrocyte cholinesterase activities were determined for 40 free-living and 12 captive common long-nosed armadillos (Dasypus novemcinctus) in order to establish normal values for monitoring pesticide exposure. Plasma cholinesterase activity ranged from 105 to 549 U/liter with no sexual or seasonal differences. Plasma values from captive animals were significantly lower than those from wild armadillos. Erythrocyte cholinesterase activity ranged from 2,915 to 15,126 U/liter with no differences detected between captive and wild animals or between sexes. However, erythrocyte cholinesterase values varied seasonally. Erythrocyte and plasma cholinesterase activities were not significantly correlated. Packed cell volume ranged from 24 to 51% and did not vary significantly between captive and wild samples, between sexes or among seasons. However, both whole blood and erythrocyte cholinesterase activities showed significant negative correlations with packed cell volume. Controlled experiments are needed to find the factors responsible for the statistically significant difference between plasma cholinesterase activities of captive and wild armadillos. The seasonal variation in erythrocyte cholinesterase activity and the negative correlation between erythrocyte cholinesterase activity and packed cell volume can be explained by an hypothesis that relates the variation in erythrocyte cholinesterase activity to variation in erythrocyte turnover rate. Future work should involve experiments to test this hypothesis.

Animals

Adenosine triphosphate content of Mycobacterium leprae: effect of purification procedures.

Various procedures to decontaminate and purify M leprae free of host tissue material resulted in total retention of their intracellular ATP and also infectiousness. The ATP content of one million M. leprae cells, isolated from either livers, spleens, or lymph nodes of infected armadillos, or a nude mouse foot pad or a human biopsy specimen, was in the range of 1.17 to 1.40 picograms. Suspensions could be decontaminated with 4% NaOH and all non-bacterial ATP could be eliminated by the combined action of trypsin, chymotrypsin, and collagenase initially, followed by Triton X-100 plus ATPase. These findings further assure that M. leprae are different from M. lepraemurium in that they can withstand even the severest purification procedures that are necessary in order for them to be used for sophisticated biochemical and metabolic studies.

Adenosine Triphosphate

Electron microscopy of peroxidase and acid phosphatase in leprous and uninfected armadillo macrophages: a macrophage subpopulation contains peroxisomes and lacks bacilli.

Lepromatous tissue from armadillos inoculated 24--36 months earlier with Mycobacterium leprae was obtained for electron microscopic studies. Cytochemically stained lepromas revealed a subpopulation of macrophages containing peroxisomes. These peroxidase reactive macrophages were not infected with bacilli. Acid phosphatase was present in macrophages and many of these were infected with bacilli and contained vacuoles and lipid globules. Within the membrane-bound vacuoles, acid phosphatase surrounded bacilli. However, the reaction product ended abruptly at a 15--40 millimicron thick zone of low electron density surrounding intact bacilli. Acid phosphatase was more intensely reactive and localized less precisely in heavily infected and vacuolated macrophages than in lightly and non-infected cells. The effectiveness of this bacillary barrier and the numerous infected macrophages with substantial acid phosphatase argue against the ability of acid phosphatase to protect host cells from leprosy bacilli. Evidence suggests a protective action of peroxidase or the rapid turnover of macrophages within lepromas. Granular and membranous debris were commonly seen within vacuoles of infected macrophages. A portion of the debris was ultrastructurally similar to bacillary matrix and was nonreactive for peroxidase and acid phosphatase. Following homogenization and centrifugation, similar materials banded with bacilli above 60% sucrose. Another portion of the debris was ultrastructurally similar to host lysosomal matrix and was reactive for acid phosphatase. Results support the concept of dual host and parasitic origins of the debris found in phagolysosomes of infected macrophages. Transparent, oval Epon defects remained eccentric to the majority of intact bacilli in centrifuged fractions. Apparently, an intrinsic property of leprosy produced these Epon defects.

Acid Phosphatase

Response of the nine-banded armadillo (Dasypus novemcinctus) to gonadotropins and steroids.

Adult male and female, nine-banded armadillos (Dasypus novemcinctus) were treated with exogenous gonadotropins and steroids to induce mating in captivity. Gonadotropin treatment induced follicular development and ovulation in the female but failed to enhance semen quality in the male. The number of ovarian follicles increased as the dosage of pregnant mare serum gonadotropin increased; ovulation rate appeared to be inversely related to dose. Mating behavior was not detected in any of the trials, but a pattern of cyclic cytological changes in urogenital smears, which could be used to detect the follicular phase of the estrous cycle, was observed. The modal duration of the estrous cycle was found to be 4 days.

Animals

Improved caging for nine-banded armadillos.

Impact resistant polyethylene cages were evaluated in these laboratories as replacements for plywood boxes for housing nine-banded armadillos. They were found to be less expensive, easier to sanitize, and to require less than one-third as much floor space per animal as the boxes. This innovation has made it practical to house large numbers of armadillos economically and conveniently in almost any animal facility.

Animals

The immune system of the nine-banded armadillo (Dasypus novemcinctus, Linn).

The armadillo is rapidly emerging as an animal for biomedical research. A morphological study of the immune system of the armadillo was undertaken to try to demonstrate a possible defect in the morphogenesis of the lymphoid organs that could account for their susceptibility to leprosy. Blood from 20 domesticated adult armadillos revealed lymphocytes predominated among circulating leukocytes in the majority of animals, whereas in wild animals neutrophils predominated. Necropsies revealed well-developed thymus glands and the thymus-dependent areas in lymph nodes and spleens contained abundant lymphoid cells. Hence, we conclude that the susceptibility of the armadillo to leprosy cannot be explained on a morphological basis.

Age Factors

Analysis for organophosphorus insecticides and metabolites.

Extraction and cleanup methods used for the analysis of organophosphate pesticides are similar to those used for chlorinated hydrocarbons but differ in some important details. Many organophosphates are lost during extraction of acetonitrile solutions containing organophosphates with petroleum ether; dichloromethane is substituted. Also, cleanup by column chromatography on mixed adsorbents containing charcoal results in better recoveries than can be obtained on Florisil alone. The detectors used for measurement of organophosphates by GLC are almost unique for this group of compounds. TLC is very useful for confirming the identities of the compounds, and several promising optical methods are available for their measurement. Methods for the analysis of metabolites of this group are basically similar, since all organophosphates undergo dealkylation reactions and cleavage of the acid anhydride bond. However, measurement of the polar group which is removed during phosphorylation or other reactions involving cleavage of the acid anhydride bond is a problem unique for each compound.

Charcoal