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R C Anderson

Publications and source records attributed to R C Anderson.

At least 91 records · Page 5Linked to original sources
PubMed2000

Bactericidal effect of sodium chlorate on Escherichia coli O157:H7 and Salmonella typhimurium DT104 in rumen contents in vitro.

Escherichia coli O157:H7 and Salmonella Typhimurium DT104 are important foodborne pathogens affecting the beef and dairy industries and strategies are sought to rid these organisms from cattle at slaughter. Both pathogens possess respiratory nitrate reductase that also reduces chlorate to the lethal chlorite ion. Because most anaerobes lack respiratory nitrate reductase, we hypothesized that chlorate may selectively kill E. coli O157:H7 and Salmonella Typhimurium DT104 but not potentially beneficial anaerobes. In support of this hypothesis, we found that concentrations of E. coli O157:H7 and Salmonella Typhimurium DT104 were reduced from approximately 1,000,000 colony forming units (CFU) to below our level of detection (< or = 10 CFU) following in vitro incubation (24 h) in buffered ruminal contents (pH 6.8) containing 5 mM added chlorate. In contrast, chlorate had little effect on the most probable number (mean +/- SD) of total culturable anaerobes (ranging from 9.9 +/- 0.72 to 10.7 +/- 0.01 log10 cells/ml). Thus, chlorate was bactericidal to E. coli O157:H7 and Salmonella Typhimurium DT104 but not to potentially beneficial bacteria. The bactericidal effect of chlorate was concentration dependent (less at 1.25 mM) and markedly affected by pH (more bactericidal at pH 6.8 than pH 5.6).

Animals↗
PubMed2000

Competitive exclusion treatment reduces the mortality and fecal shedding associated with enterotoxigenic Escherichia coli infection in nursery-raised neonatal pigs.

We have previously reported that the administration of a competitive exclusion culture (PCF-1), derived from the cecal microflora of a young, healthy pig and maintained in a continuous flow fermentation system to neonatal pigs resulted in a decrease in the incidence of fecal shedding and cecal colonization by Salmonella choleraesuis in pigs at weaning. In the present experiment, we describe the effects of the administration of a derivative of the PCF-1 culture, RPCF, against an enterotoxigenic E. coli infection in neonatal pigs raised off-sow. The administration of RPCF at 12 and 24 hours after birth resulted in significant (P < 0.05) reductions in mortality, incidence of fecal shedding, and in gut colonization by E. coli when compared to control values. The RPCF reduced mortality from 17.5%, observed in untreated pigs, to 4.4% in RPCF-treated pigs. Fecal shedding of E. coli was reduced significantly (P < 0.05) in RPCF-treated pigs between Days 1 and 3 post-challenge. These results indicate that the RPCF culture is effective against one of the most important causes of neonatal scours (E. coli infections) in piglets.

Animals↗
PubMed1999

Prevalence of Campylobacter spp isolated from the intestinal tract of pigs raised in an integrated swine production system.

OBJECTIVE: To enumerate the prevalence of Campylobacter isolates in the intestinal tract of market-weight swine raised in an integrated swine operation in Texas. SAMPLE POPULATION: Samples of cecal contents were collected from 595 pigs (mean body weight, 110 kg [242 lb]) at time of slaughter. Pigs were off-spring of Yorkshire-Landrace sows and Duroc or Hampshire boars. Pigs originated from 4 farrow-to-finish farms. PROCEDURE: During a 9-month period, visits were made to a slaughter plant to remove cecal contents from market-weight hogs. Samples were obtained from 50 pigs/visit from designated farms so that samples were obtained 3 times from pigs of each of 4 farms. Isolation of Campylobacter spp was accomplished by use of enrichment broth and restrictive media, using microaerophilic conditions. RESULTS: Campylobacter spp were isolated from 70 to 100% of the pigs, depending on the farm and the date the samples were collected. Campylobacter coli was isolated from 20 to 100% (mean, 60%) of samples, and C jejuni was isolated from 0 to 76% (mean, 31%) of samples. Campylobacter lari was isolated from 2 pigs. Concentrations of C coli or C jejuni ranged from 10(3) to 10(7) colony-forming units/g of cecal content. CONCLUSIONS AND CLINICAL RELEVANCE: Campylobacter coli generally is accepted as a common inhabitant of the intestinal tract of swine. However, analysis of results of this study suggests that a relatively high prevalence of C jejuni may be found in pigs raised on specific farms.

Animals↗
PubMed1999

Prevalence of Campylobacter, Salmonella, and Arcobacter species at slaughter in market age pigs.

A survey was conducted to determine the prevalence of Campylobacter, Salmonella, and Arcobacter species in market age pigs from an integrated swine operation in Texas. Our findings indicate that farms from this commercial operation were heavily contaminated with Campylobacter and Salmonella, that the isolation rates of C. jejuni were higher than predicted, and that there was a low prevalence of Arcobacter.

Animals↗
PubMed1999

Prophylactic administration of immune lymphokine derived from T cells of Salmonella enteritidis-immune pigs. Protection against Salmonella choleraesuis organ invasion and cecal colonization in weaned pigs.

Experiments involving 132 weaned piglets were conducted to evaluate the efficacy of a Salmonella enteritidis-immune lymphokine (PILK) derived from the T cells of Salmonella enteritidis (SE)-immunized pigs to protect weaned piglets from Salmonella choleraesuis (SC) infection. Fourteen-to-seventeen day-old piglets were weaned and randomly placed into 1 of 5 groups: (1) noninfected controls, (2) PILK 3X noninfected, (3) SC infected controls, (4) PILK 1X SC infected, and (5) PILK 3X SC infected. PILK was given orally either one time (PILK 1X) or three times (PILK 3X) over 14 days. One hour after the first PILK administration on day 0, piglets were orally challenged with 10(7) cfu of SC. Weights were recorded on day 0, day 7, and day 14. On day 14, pigs in groups 3, 4, and 5 were sacrificed and organs and lymph tissue were cultured for the presence of SC. Three replicates of this experiment were pooled and anlayzed. A significant reduction in the number of pigs positive for SC in the liver, lung, and spleen was found in group 5 (PILK 3X) when compared to group 3 (inf. cont. p < 0.001[). The number of SC positive cecal contents was dramatically reduced in group 5 group when compared to group 3, with the PILK 3X group showing 13% positive pigs versus 55.2% in the infected controls (p < 0.05). Weight gain over the 14 day study in the infected PILK 3X group (group 5) was found to be comparable to the gain observed in the group 1 (noninfected controls). The pigs receiving PILK 3X (group 2) with no SC challenge gained significantly more weight than all other groups, including the noninfected controls (group 1 p < 0.05[). The results of these experiments indicate that PILK protects against SC infection in weaned pigs while enhancing performance in the presence of an SC infection.

Animals↗
PubMed1999

The current role of mediastinoscopy in the evaluation of thoracic disease.

OBJECTIVE: Mediastinoscopy is a common procedure used for the diagnosis of thoracic disease and the staging of lung cancer. We sought to determine the current role of mediastinoscopy in the evaluation of thoracic disease. METHODS: We conducted a retrospective review of all mediastinoscopies performed by members of our service between January 1988 and September 1998. RESULTS: We performed mediastinoscopies on 2137 patients. A total of 1745 patients underwent mediastinoscopy for known or suspected lung cancer. In 422 of these procedures, N2 or N3 disease was identified; only 28 of these patients underwent resection. The remaining 1323 had no evidence of metastatic disease. In these patients 947 had lung cancer. Only 76 of the patients with lung cancer were found to have N2 disease at exploration. Among the 1323 patients with a negative mediastinoscopy result, 52 underwent resection of a nonbronchogenic malignancy, and 217 had resection of a benign lesion. A total of 392 patients underwent mediastinoscopy for the evaluation of mediastinal adenopathy in the absence of any identifiable pulmonary lesion. Of these, 161 had a nonbronchogenic malignancy, 209 had benign disease, and 25 had no diagnosis established; mediastinoscopy established a definitive diagnosis in 93.6% of patients. In the entire group of 2137 patients, there were 4 perioperative deaths and 12 complications. Only one death was directly attributed to mediastinoscopy. No deaths or complications occurred in patients undergoing mediastinoscopy for benign disease. CONCLUSIONS: Mediastinoscopy is a highly effective and safe procedure. We believe that mediastinoscopy should currently be used routinely in the diagnosis and staging of thoracic diseases.

Aged↗
PubMed1999

Affinity NMR: decoding DNA binding.

We have shown that affinity NMR can be used to edit a NMR spectrum so that ligands that have affinity to DNA can be observed in the presence of other nonbinding molecules. Diffusion encoded spectroscopy (DECODES) can be used to identify the binding ligands. We were able to identify Hoechst 33342 as binding to the Drew-Dickerson dodecamer d(CGCGAATTCGCG)2 in the presence of the nonbinding molecules adenine, adenosine, and thiamine. Affinity NMR appears to be readily applicable to DNA systems for the following reasons. (1) The relaxation rate of the DNA oligonucleotides is favorable, thus the signal intensity loss due to relaxation is not severe. (2) A comparison of the patterns of the DNA cross-peaks upon binding in the two-dimensional total correlation spectroscopy and correlation spectroscopy spectrum are easily performed, and the ligand signals in the two-dimensional DECODES spectrum can be readily identified. (3) The aromatic part of the DNA spectrum is devoid of 2D cross-peaks in these correlation spectra, greatly facilitating the interpretation of the bound ligand in the DECODES spectrum.

Adenine↗
PubMed1999

Contact analysis of a posterior cervical spine plate using a three-dimensional canine finite element model.

The development of a three-dimensional finite element model of a posteriorly plated canine cervical spine (C3-C6) including contact nonlinearities is described. The model was created from axial CT scans and the material properties were derived from the literature. The model demonstrated sufficient accuracy from the results of a mesh convergence test. Significant steps were taken toward establishing model validation by comparison of plate surface strains with a posteriorly plated canine cervical spine under three-point bending. This model was developed to better characterize the contact pressures at the various interfaces under average physiologic canine loading. The analysis showed that the screw-plate interfaces had the highest values of all the mechanical parameters evaluated.

Animals↗
PubMed1998

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Animals↗
PubMed1998

Halicephalobus gingivalis (Stefanski, 1954) from a fatal infection in a horse in Ontario, Canada with comments on the validity of H. deletrix and a review of the genus.

Although the original description given by Stefanski (1954) was satisfactory, Anderson & Bemrick (1965), in describing H. deletrix (= Micronema deletrix), claimed Stefanski's description was "inadequate" and the species a "species inquirenda". Thus, infections in horses and humans have been assigned to H. deletrix. We believe the species reported in horses and humans is H. gingivalis and that H. deletrix is its synonym. H. gingivalis is separated herein from forms found free-living. The genital tract in the advanced fourth stage of H. gingivalis is didelphic and amphidelphic and terminal ends of the horns are reflected, the anterior one ventrally, the posterior one dorsally. In the adult parthenogen the latter forms a short ovary, whereas most of the anterior horn forms a combined uterus-oviduct as a receptacle for a single large egg which is laid in the 2-cell or multi-cell stage. Eggs in the 2-cell stage embryonated to larvae in 17 hours at 28 degrees C but did not hatch until an additional 24 hours. First-stage larvae were unusually large and variable in length (136-199 microns x = 168). Inactive third-stage larvae were 180-240 microns (x = 203) in length. The possible route of infection in horses and humans is briefly discussed.

Animals↗
PubMed1998

Hypoglycemic effects of a novel fatty acid oxidation inhibitor in rats and monkeys.

Increased fatty acid oxidation contributes to hyperglycemia in patients with non-insulin-dependent diabetes mellitus. To improve glucose homeostasis in these patients, we have designed a novel, reversible inhibitor of carnitine palmitoyl-transferase I (CPT I) that potently inhibits fatty acid oxidation. SDZ-CPI-975 significantly lowered glucose levels in normal 18-h-fasted nonhuman primates and rats. In rats, glucose lowering required fatty acid oxidation inhibition of > or = 70%, as measured by beta-hydroxybutyrate levels, the end product of beta-oxidation. In cynomolgus monkeys, comparable glucose lowering was achieved with more modest lowering of beta-hydroxybutyrate levels. SDZ-CPI-975 did not increase glucose utilization by heart muscle, suggesting that CPT I inhibition with SDZ-CPI-975 would not induce cardiac hypertrophy. This was in contrast to the irreversible CPT I inhibitor etomoxir. These results demonstrate that SDZ-CPI-975 effectively inhibited fatty acid oxidation and lowered blood glucose levels in two species. Thus reversible inhibitors of CPT I represent a class of novel hypoglycemic agents that inhibit fatty acid oxidation without inducing cardiac hypertrophy.

3-Hydroxybutyric Acid↗
PubMed1998

Acute filariasis in a springhaas.

A 2-yr old Springhaas (Pedetes capensis; Pedetidae, Rodentia) imported into the USA from the Republic of South Africa was severely debilitated as the result of abberant migrations of adult Filaria versterae (Filarioidea: Filariidae) normally confined to the subcutaneous tissues of this host in Africa. Some nematodes invaded the peritoneal and thoracic cavities, the pericardial sac and the lungs. Invasion of the lungs resulted in life-threatening respiratory distress necessitating euthanasia. Filaria versterae is redescribed.

Animals↗
PubMed1998

Carnitine palmitoyltransferase: a viable target for the treatment of NIDDM?

Inhibition of fatty acid oxidation is well recognized as a potentially effective mechanism for controlling glycemia in non-insulin-dependent diabetes mellitus (NIDDM). However, a direct targeting of inhibition of the intramitochondrial beta-oxidation pathway or an indirect modulation of fatty acid oxidation by inhibition of substrate release from adipose stores has been fraught with lack of efficacy, unacceptable side-effects or both. Focus has therefore recently been directed towards the carnitine palmitoyltransferase (CPT) system, a three-component system necessary for the transfer of long-chain fatty acids into the intramitochondrial matrix. This article will briefly review the background for fatty acid oxidation inhibition in NIDDM and then focus on the progress in the biological understanding and drug discovery targeting of the CPT system for the treatment of NIDDM. Based upon the review, it is concluded that mechanism-based hepatic and myocardial toxicities in normal animals and a potential for a lack of human efficacy may pose insurmountable hurdles for the development of CPT inhibitors for the treatment of NIDDM.

Animals↗
PubMed1997

Stress analysis of halo pin insertion by non-linear finite element modeling.

Halo fixation is associated with a high complication rate. The most common complications are loose pins and pin site infections believed to be exacerbated by loose pins. Although pin designs and the technique of pin insertion have changed little in over 30 years, the pin/skull mechanics are poorly understood. Halo pin insertion was modeled using nonlinear finite element analyses to determine the stress distribution in the human skull underlying and surrounding the point of pin fixation. Model validity was established by comparing pin insertion depth and the profile of the hole generated in the bone to the results of experimental mechanical tests. The region surrounding the pin tip within 1 mm was found to undergo plastic deformation and compressive loading in excess of the compressive yield strength of cortical bone. The implication is that damaged bone in this region is responsible for the high incidence of halo pin loosening. Resorption or migration of bone particles with periodic relief of compression in this region due to daily cyclic forces might result in an enlarged pin site and eventually, a loose pin.

Bone Nails↗
PubMed1997

Characteristics of a nitropropanol-metabolizing bacterium isolated from the rumen.

We report some characteristics of a ruminal bacterium (strain NPOH1) that metabolizes 3-nitropropanol, the toxic principle of various milk vetchs that are distributed worldwide. The gram-positive bacterium was nonmotile and did not produce spores. Growth of strain NPOH1 occurred under anaerobic conditions and was supported by the electron acceptors 3-nitropropanol, 3-nitropropionate, nitrate, 2-nitropropanol, nitroethane, nitroethanol, or 3-nitro-1-propyl-beta-D-glucopyranoside (miserotoxin). Other potential electron acceptors, namely sulfate, sulfite, azide, chlorate, perchlorate, nitrite, fumarate, 2-nitrobutane, or nitrobenzene, did not support growth. Formate, lactate, and H2 stimulated growth of strain NPOH1 in the presence of the appropriate nitrocompound, whereas a variety of other potential H2 donors did not. When grown in medium containing both nitrate and either 3-nitropropanol or 3-nitropropionate, nitrate was the preferred acceptor. Strain NPOH1 reduced nitrate to nitrite and, when grown with excess reductant, nitrite was further reduced to ammonia. The products formed during the metabolism of 3-nitropropanol and 3-nitropropionate by mixed ruminal populations, 3-aminopropanol and beta-alanine, were not found in culture fluids of strain NPOH1. Analysis of total cellular fatty acid profiles and of the mole percent guanine plus cytosine suggests that strain NPOH1 is a novel bacterium. The capacity of strain NPOH1 to metabolize 3-nitropropanol suggests that this organism may play an important role in detoxification of 3-nitropropanol in the rumen.

Animals↗