Rhodotorula minuta fungemia in a ewe lamb.

An 8-month-old crossbred ewe, normal upon physical examination, was humanely euthanized for tissue collection. After approximately 3 weeks in tissue culture, fungi began budding out of cells obtained from the choroid plexus. After an additional 3 weeks, budding was observed in kidney cell cultures and eventually in monocyte cultures as well. Serum from the lamb was submitted to the Veterinary Diagnostic Laboratory at Colorado State University for fungal diagnosis and was found negative for Aspergillus, Blastomyces, Coccidioidomycosis and Histoplasmosis. DNA was isolated from fungi collected from tissue culture supernatants and used in a set of pan-fungal PCR assays with DNA from Candida acting as a positive control. PCR products were sequenced and BLAST analysis performed. The unknown fungal sequence aligned with 100% identity to Rhodotorula minuta an emerging opportunistic pathogen. Samples were submitted to The Fungal Testing Laboratory at The University of Texas Health Science Center at San Antonio for additional validation. We believe this to be the first report of Rhodotorula fungemia in a sheep in the United States.

Escherichia coli O157 in feedlot cattle feces and water in four major feeder-cattle states in the USA.

The prevalence of Escherichia coli O157 was determined in 10662 fecal samples, 2130 water and 1132 water tank-sediment samples collected during the summer months in 2001 from 711 pens in 73 feedlots located in Kansas, Nebraska, Texas, or Oklahoma, USA. Overall, 10.2% of fecal samples were positive for E. coli O157, with 52% of the pens and 95.9% of the feedlots having at least one positive fecal sample. There were no differences among states or months in the fecal prevalences. Water or water tank-sediment was positive in 13.1% of the water tanks, and 60.3% of feedlots had at least one positive tank. Cattle were more likely to be shedding E. coli O157 in pens with positive water tanks, and water was more likely to be positive when E. coli O157 was detected in the sediment.

Characterization of incompletely typed rotavirus strains from Guinea-Bissau: identification of G8 and G9 types and a high frequency of mixed infections.

Among 167 rotavirus specimens collected from young children in a suburban area of Bissau, Guinea-Bissau, from 1996 to 1998, most identifiable strains belonged to the uncommon P[6], G2 type and approximately 50% remained incompletely typed. In the present study, 76 such strains were further characterized. Due to interprimer interaction during the standard multiplex PCR approach, modifications of this procedure were implemented. The modified analyses revealed a high frequency of G2, G8, and G9 genotypes, often combined with P[4] and/or P[6]. The Guinean G8 and G9 strains were 97 and 98%, respectively, identical to other African G8 and G9 strains. Multiple G and/or P types were identified at a high frequency (59%), including two previously undescribed mixed infections, P[4]P[6], G2G8 and P[4]P[6], G2G9. These mixed infections most likely represent naturally occurring reassortance of rotavirus strains. Detection of such strains among the previously incompletely typed strains indicates a potential underestimation of mixed infections, if only a standard multiplex PCR procedure is followed. Furthermore cross-priming of the G3 primer with the G8 primer binding site and silent mutations at the P[4] and P[6] primer binding sites were detected. These findings highlight the need for regular evaluation of the multiplex primer PCR method and typing primers. The high frequency of uncommon as well as reassortant rotavirus strains in countries where rotavirus is an important cause of child mortality underscores the need for extensive strain surveillance as a basis to develop appropriate rotavirus vaccine candidates.

Characterization of nontypeable rotavirus strains from the United States: identification of a new rotavirus reassortant (P2A[6],G12) and rare P3[9] strains related to bovine rotaviruses.

Among 1316 rotavirus specimens collected during strain surveillance in the United States from 1996 to 1999, most strains (95%) belonged to the common types (G1 to G4 and G9), while 5% were mixed infections of common serotypes, rare strains, or not completely typeable. In this report, 2 rare (P[9],G3) and 2 partially typeable (P[6],G?; P[9],G?) strains from that study were further characterized. The P[6] strain was virtually indistinguishable by hybridization analysis in 10 of its 11 gene segments with recently isolated P2A[6],G9 strains (e.g., U.S.1205) from the United States, but had a distinct VP7 gene homologous (94.7% a.a. and 90.2% nt) to the cognate gene from P1B[4],G12 reference strain L26. Thus, this serotype P2A[6],G12 strain represents a previously unrecognized reassortant. Three P3[9] strains were homologous (97.8-98.2% aa) in the VP8 region of VP4 to the P3[9],G3 feline-like reference strain AU-1, but had a high level of genome homology to Italian bovine-like, P3[9],G3 and P3[9],G6 rotavirus strains. Two of the U.S. P3[9] strains were confirmed to be type G3 (97.2-98.2% VP7 aa homology with reference G3 strain AU-1), while the other was most similar to Italian bovine-like strain PA151 (P3[9],G6), sharing 99.0% a.a. homology in VP7. Cross-neutralization studies confirmed all serotype assignments and represented the first detection of these rotavirus serotypes in the United States. The NSP4 genes of all U.S. P3[9] strains and rotavirus PA151 were most closely related to the bovine and equine branch within the DS-1 lineage, consistent with an animal origin. These results demonstrate that rare strains with P and G serotypes distinct from those of experimental rotavirus vaccines circulate in the United States, making it important to understand whether current vaccine candidates protect against these strains.

Surveillance of rotavirus strains in the United States: identification of unusual strains. The National Rotavirus Strain Surveillance System collaborating laboratories.

Rotavirus strains from 964 fecal specimens collected from children at 11 U.S. hospital laboratories from November 1997 to March 1998 and from samples collected at 12 laboratories from November 1998 to March 1999 were typed for G and P proteins. Serotype G1 was the predominant serotype in 1997-1998 (88%), followed by G2 (6.2%), G9 (3.3%), and G3 (1.5%). This pattern was similar to that seen in 1998-1999: G1 (79%), G2 (15%), G9 (3.0%), G4 (1.6%), and G3 (0.3%). Novel P[9] strains were identified in both seasons, and analysis of a 364-nucleotide fragment from gene segment 4 of one of the strains demonstrated 97.3% nucleotide identity with the prototype P3[9],G3 strain, AU1, isolated in Japan. This is the first report of a human AU1-like strain in the United States. These results reinforce our initial findings that serotype G9 persists in the United States but has not become a predominant strain and that the common serotypes G1 to G4 account for almost 90% of strains in circulation. Other uncommon strains exist in the United States but may have been overlooked before because of their low prevalence and the use of inadequate diagnostic tools.

Spin dynamics of Carr-Purcell-Meiboom-Gill-like sequences in grossly inhomogeneous B(0) and B(1) fields and application to NMR well logging.

The spin dynamics for Carr-Purcell-Meiboom-Gill-like sequences is analyzed in grossly inhomogeneous B(0) and B(1) fields. This problem is important for many applications, especially when the bandwidth of the signal is excitation limited. Examples include stray-field NMR or inside-out NMR probes used in well logging. The amplitudes of the first few echoes exhibit a characteristic transient behavior but quickly approach a smooth asymptotic behavior. For simple Hamiltonians without scalar or dipolar couplings, the evolution of a refocusing subcycle for a given isochromat is described by a rotation. Simple expressions for the signal of the Nth echo are derived in terms of these effective rotations that have a simple geometrical interpretation. It is shown that the asymptotic behavior is controlled by the direction of the axis of these effective rotations and the signal is dominated by magnetization "spin-locked" to the rotation axis. The phase of the signal is independent of the details of the field inhomogeneities. Relaxation in inhomogeneous fields leads to a signal decay that is in general nonexponential with an initial decay rate that is a weighted sum of T(-1)(1) and T(-1)(2). At long times, the echo amplitudes decay to a finite value. Phase cycling eliminates this offset. The effect of diffusion is also studied. This analysis has been applied to an inside-out NMR well logging apparatus. Good quantitative agreement is found between measurements and calculations that are based on the measured B(0) and B(1) field maps.

Effect of booster vaccination with a multivalent clostridial bacterin-toxoid on sudden death syndrome mortality rate among feedlot cattle.

OBJECTIVE: To determine whether booster vaccination with a multivalent clostridial bacterin-toxoid would affect the sudden death syndrome (SDS) mortality rate among feedlot cattle. DESIGN: Field trial. ANIMALS: 83, 115 cattle at a Nebraska feedlot. PROCEDURE: Cattle arriving at the feedlot underwent routine processing according to established protocol. All cattle received a sequentially numbered ear tag and a 2-ml dose of a multivalent bacterin-toxoid designed to protect cattle against Clostridium chauvoei, C speticum, C novyi, C sordellii, and C perfringens types C and D. Approximately 90 days prior to slaughter, growth promotants were implanted in all cattle, and cattle were allocated to a treatment or control group on the basis of the last digits of their ear tag numbers. Cattle in the treatment group received a second 2-ml dose of clostridial bacterintoxoid; control cattle did not. RESULTS: Significant differences between groups in regard to crude, feeding pen, or SDS mortality rates were not detected. Sudden death syndrome mortality rate across both groups was 0.24%. If the SDS mortality rate in midwestern feedlot cattle was reduced > or = 40% by booster vaccination with a multivalent clostridial bacterin-toxoid, this experiment included enough animals to have a 90% probability of detecting that difference. CLINICAL IMPLICATIONS: Booster vaccination with a multivalent clostridial bacterin-toxoid does not affect SDS mortality rate among feedlot cattle.

The risks and prevention of contamination of beef feedlot cattle: the perspective of the United States of America.

There are currently no scientifically defined critical management points or critical control points to manage foodborne pathogens at the pre-harvest level. Research is ongoing: much of the pre-harvest research is funded by producer organisations. The beef industry has Beef Quality Assurance (BQA) programmes in place and these are dynamic. Groups of cattlemen have made a very strong commitment to reducing foodborne pathogens in beef. Fewer Escherichia coli O157:H7 organisms are shed by feedlot cattle near the end of the feeding period than by newly arrived cattle. Moreover, there is less shedding of the organisms in cattle of slaughter age than in younger cattle. The prevalence of E. coli O157:H7 in feedlot cattle is similar to that in range cattle. This suggests that concentrating cattle in feedlot dirt pens does not increase the risk of shedding E. coli organisms. Pen maintenance, considered a good management practice, appears to be an adequate means of keeping pathogen levels in pens low. It is not likely that pre-harvest food safety programmes will eliminate the threat of pathogens such as E. coli O157:H7 or Salmonella. The management of foodborne pathogens will become part of an integrated programme to enhance food safety which includes the producer, the packer, the distributors, retailers and the consumer. The feedlot industry initiated a residue avoidance programme several years ago. As a result, the risk of chemical residues in beef from feedlots in the United States of America is near zero. Hazard analysis and critical control point-type prevention programmes, using scientifically based critical management points, will help ensure that the risk remains negligible.

Haptoglobin response to clinical respiratory tract disease in feedlot cattle.

OBJECTIVE: To quantify haptoglobin response to respiratory tract disease in feedlot cattle, and to investigate its ability to predict disease outcome and response to antibiotic treatment. DESIGN: Randomized clinical trial. ANIMALS: 60 feedlot calves with clinical respiratory tract disease. PROCEDURE: Calves were randomly assigned to receive a standard antibiotic treatment regimen (TRT), or to observation pens without antibiotic treatment. Serum haptoglobin concentration was measured at initial and final examinations. Calves were examined for presence of gross pulmonary lesions at slaughter. RESULTS: Mean +/- SD serum haptoglobin concentration at initial examination was 67 +/- 108 mg/dl, with range of 0 to 508 mg/dl. Haptoglobin concentration at initial examination was similar for the TRT group and the group that did not receive antibiotic treatment, but at final examination, TRT-group calves had lower (P < 0.01) mean values. Calves receiving antibiotic treatment had haptoglobin concentration at or near zero at final examination. Calves not receiving antibiotic treatment had only slightly lower mean haptoglobin concentration at final examination, compared with initial examination. Within treatment groups, haptoglobin concentration was similar for cases with different outcomes. Calves with gross pulmonary lesions at slaughter had numerically higher, although statistically similar, haptoglobin concentrations at initial examination, compared with calves without lesions. CONCLUSIONS: Feedlot cattle with clinical respiratory tract disease have a large and variable haptoglobin response. Antibiotic treatment resulted in lower serum haptoglobin values, although low values were not required for full clinical recovery. CLINICAL RELEVANCE: Serum haptoglobin concentration may be an indicator of response to antibiotic therapy, although it appears to be unrelated to case severity or need for treatment.

Serum haptoglobin concentrations in a population of feedlot cattle.

OBJECTIVE: To determine serum haptoglobin concentrations in a population of feedlot cattle and evaluate their usefulness in predicting subsequent clinical respiratory tract disease. DESIGN: Prospective longitudinal study. ANIMALS: 366 beef calves. PROCEDURE: Serum samples were obtained at feedlot entry and 40 and 65 days on feed (DOF). Calves were observed daily for clinical signs of respiratory tract disease. The lungs of 144 of the calves were evaluated at slaughter for the presence of gross lesions of pneumonia. RESULTS: 58% of the calves had detectable serum haptoglobin concentration in at least 1 sample. The proportion of calves with detectable haptoglobin were similar at each sample collection time. A higher proportion of the calves had values > 10 mg/dl at 40 DOF. The proportion of calves observed with clinical disease during the 10-day period after the 40 DOF sample increased (P < 0.10) as serum haptoglobin concentration increased. At 65 DOF, calves with serum haptoglobin value > 10 mg/dl had a higher (P < 0.05) rate of subsequent clinical respiratory tract disease than did calves with lower values. The proportion of calves with gross pulmonary lesions slaughter increased (P < 0.05) from 39% among calves without detectable serum haptoglobin concentration in any of the 3 samples to 63% among calves with at least 1 observed value > 10 mg/dl. CONCLUSIONS: We observed associations between serum haptoglobin concentration and subsequent clinical respiratory tract disease and pulmonary lesions at slaughter. However, serum haptoglobin concentration alone is not adequate for prediction of clinical disease. CLINICAL RELEVANCE: The usefulness for cross-sectional sampling of serum haptoglobin concentration as a diagnostic tool for clinical respiratory tract disease in feedlot cattle appears to be limited.

A comparison of the various routes of administration of erythromycin in cattle.

A comparison of i.v., i.m. and s.c. administration erythromycin base in polyethylene glycol at 15 mg/kg and 30 mg/kg body weight was carried out in beef-type calves of approximately 200 kg body weight. Additional evaluations were carried out with oral administration of erythromycin phosphate and erythromycin stearate. Absorption of erythromycin was very slow by both the i.m. and s.c. routes of administration with a Kab of 0.0135 min-1 and 0.0185 min-1 for i.m. and 0.0032 min-1 and 0.0074 min-1 for s.c. at 15 mg/kg and 30 mg/kg, respectively. The bioavailability (32-42%) and peak serum concentrations were much lower with s.c. than with i.m. (60-65%) administration. The disposition of erythromycin administered i.v. appeared to be representative of dose-dependent kinetics rather than dose-independent first-order kinetics inasmuch as the elimination half-time (t1/2B) increased from 174.5 +/- 13 min for the 15 mg/kg dosage to 239 +/- 10.8 min with 30 mg/kg dosage. An acute apparent cardiovascular effect accompanied i.v. administration of erythromycin at 30 mg/kg dosage but not at 15 mg/kg. Severe diarrhea followed oral administration of either erythromycin phosphate or erythromycin stearate.

Effect of sorghum grain variety and reconstitution on site and extent of starch and protein digestion in steers.

Hetero-yellow (HY), red (RED) and brown (BR, high tannin) sorghums were fed dry-rolled or reconstituted (RED and BR only) to evaluate the effect of variety and reconstitution on the site and extent of starch and protein digestion in steers fitted with ruminal, duodenal and ileal cannulae. Processed grains were incorporated into 88% sorghum (DM basis) diets fed at 2% of body weight in a 5 X 5 Latin square. Ruminal fermentation of organic matter, starch and protein tended to be lower for the dry-rolled RED than for either the dry-rolled HY or BR sorghum. Digestion of organic matter (OM) and starch in the small intestine was very low for dry-rolled sorghums. Total tract starch digestibility was lower for the dry-rolled RED sorghum (86.9%) than the BR (90.8%) and HY (91.4%). Nitrogen (N) digestibility ranged from 53.1% for the dry-rolled BR to 64.5% for the HY. Tannins were extensively (95.2%) degraded in the rumen, which may have enhanced fermentation of the BR sorghum. Reconstitution increased (P less than .05) total-tract starch digestion of the RED and tended to increase starch digestion of the BR as well. Total N flow to the duodenum tended to increase with reconstitution, with most of the increase being due to greater (P less than .05) microbial-N. Reconstitution also increased (P less than .05) total-tract N digestibility of the RED. The response to reconstitution for the RED sorghum appeared to be due primarily to an increase (P less than .10) in the extent of fermentation of organic matter and starch in the rumen. Reconstitution of BR, however, enhanced disappearance of starch from the small intestine. In both cases, most (97.3%) of the digestible starch of the reconstituted sorghums had disappeared before the terminal ileum. In contrast, 14.5% (621 g) of the digestible starch of dry-rolled RED disappeared in the large intestine. Sorghum grain variety and reconstitution appear to alter site and extent of starch and protein digestion, which may result in variable performance of cattle fed sorghum grain diets.

Roux-Y intestinal bypass for administration of sorbents in uremia.

In order to minimize interaction of sorbents with food and digestive secretions, an intestinal bypass was created for sorbent administration in normal and uremic rats (N = 18) and goats (N = 5). Two separate limbs of small intestine were fashioned, one for food absorption and one for sorbent function, which joined at a Roux-Y anastomosis before the cecum. Particulate sorbent suspensions were injected into the intestine via a cutaneous stoma, and were excreted with food wastes in the feces. In animals with normal kidneys, sorbent function was calculated from changes in fecal and urinary excretion. Nitrogen clearance by the intestinal bypass was 20 to 40% of normal renal clearance in rats and goats. Potassium clearance was 40% of normal renal clearance in rats, and over 100% in goats. Sorbent treatment in anephric animals caused serum urea nitrogen concentrations to stabilize at 210 mg/dl in rats, and 110 mg/dl in goats. Serum potassium concentrations stabilized at 4.5 mEq/liter in rats, and fell to 2 mEq/liter in goats. Water balance was maintained by producing a mild osmotic diarrhea. At least three substances which accumulate in renal failure--urea, potassium, and water--were removed in therapeutically significant amounts.

Infrared techniques for measuring temperature and related phenomena of microcircuits.

A flexible ir system affords several ways to approach the investigation of temperature, dependent phenomena on small geometry targets. The appropriate technique will generally depend upon the objective of the particular investigation. Procedures for determining thermal time response, temperature mapping, and thermal image generation are demonstrated by example.