Identification of Brucella spp. in feral swine (Sus scrofa) at abattoirs in Texas, USA.

Various tissues, nasal swabs, urine and blood samples were collected from 376 feral swine at two federally inspected abattoirs in Texas during six separate sampling periods in 2015. Samples were tested for Brucella spp. by culture and serology. Brucella spp. were cultured from 13.0% of feral swine, and antibodies were detected in 9.8%. Only 32.7% of culture-positive feral swine were also antibody positive, and 43.2% of antibody-positive feral swine were culture positive. Approximately, the same number of males (14.0%) and females (12.1%) were culture positive, and slightly more males (10.5%) than females (8.7%) were antibody positive. Our results indicate that serology likely underestimates the prevalence of feral swine infected, and that those who come in contact with feral swine should be aware of the symptoms of infection with Brucella spp. to ensure prompt treatment.

Clinical benefits of continuous leukocyte filtration during cardiopulmonary bypass in patients undergoing valvular repair or replacement.

Valve operations in the form of repair or replacement make up a significant population of patients undergoing surgical procedures in the USA annually with the use of cardiopulmonary bypass. These patients experience a wide range of complications that are considered to be mediated by activation of complement and leukocytes. The extracorporeal perfusion circuit consists of multiple synthetic artificial surfaces. The biocompatibility of the blood contact surfaces is a variable that predisposes patients to an increased risk of complement mediation and activation. This can result in an inflammatory process, causing leukocytes to proliferate and sequester in the major organ systems. The purpose of this study was to determine whether filtration of activated leukocytes improved clinical outcomes following surgical intervention for valve repair or replacement. In this paper, we report a retrospective matched cohort study of 700 patients who underwent valve procedures from June 1999 to December 2002. The control group (CG) consisted of patients who had a conventional arterial line filter. In the study group (SG), patients had a conventional arterial line filter and a leukocyte arterial line filter (Pall Medical, NY). In the SG, blood diverted to the cardioplegia system was also leukocyte depleted to enhance myocardial preservation by adapting this device to the outflow port on the filter. Patient characteristics were similar for the SG and the CG, including 228 males and 122 females, mean age (62.4 versus 64.2 years), cardiopulmonary bypass time (127+/-64 versus 116+/-53 min), and aortic crossclamp time (84+/-23 versus 81+/-23 min). Our results demonstrate that the SG achieved statistically significant reduction in the time to extubation (p =0.03) and the number of patients with prolonged intubation in excess of 24 hours (p <0.04), in addition to improved postoperative oxygenation (p=0.01), and decreased length of hospital stay (p =0.03). We believe that leukocyte filters are clinically beneficial, as demonstrated by the results presented in this study.

Surface modification of poly(methyl methacrylate) used in the fabrication of microanalytical devices.

We report here the chemical modification of poly(methyl methacrylate) (PMMA) surfaces by their reaction with the monoanion of alpha,omega-diaminoalkanes (aminolysis reaction) to yield amine-terminated PMMA surfaces. It is found that the amine functionalities are tethered to the PMMA backbone through an alkane bridge to amide bonds formed during the aminolysis of the surface ester functionalities. The distribution of the amine termini is quite uniform as judged by fluorescence micrographs. It is found that the electroosmotic flow in aminated PMMA microchannels is reversed when compared to that in unmodified channels. In addition, it is demonstrated that enzymes can be immobilized onto the amine-terminated PMMA surfaces and are effective in the restriction digestion of dsDNAs. Finally, the availability of the surface amine groups is further demonstrated by their reaction with n-octadecane-1-isocyanate to form PMMA surfaces terminated with well-ordered and highly crystalline octadecane chains.

The effect of glucocorticosteroid treatment on dentine formation in the Lewis rat, a histological study.

Glucocorticosteroids are widely used in the treatment of chronic illnesses and have been reported to cause premature obliteration of the pulp space. During the active stages of dentinogenesis, odontoblasts are growth hormone receptor (GHr) positive. The aims of this study were to determine if the glucocorticosteroid, prednisone, affected the rate of dentine deposition and odontoblast expression of GHr in the rat molar. Following subcutaneous injection of 0.05 mg/kg, 1.0 mg/kg or 5.0 mg/kg prednisone for 20 days, immature and mature molars from rats aged 3 and 6 weeks respectively, were examined histologically. Distribution of GHr expression was determined immunohistochemically. No morphological differences were observed in molars from prednisone treated animals. Prednisone did not appear to enhance dentine deposition in immature molars but in mature molars significantly increased dentine deposition on the roof of the pulp chamber at a dosage of 5.0 mg/kg (p < 0.001). In all immature molars, odontoblasts and pulp cells expressed GHr immunoreactivity. In mature molars, odontoblasts and pulpal cells from controls did not show GHr immunoreactivity. However, odontoblasts and pulp cells were GHr immunoreactive in mature molars from animals treated with prednisone.

High-resolution near-infrared imaging of DNA microarrays with time-resolved acquisition of fluorescence lifetimes.

Ultrasensitive, near-infrared (NIR), time-resolved fluorescence is evaluated as a detection method for reading DNA hybridization events on solid surfaces for microarray applications. In addition, the potential of mulitiplexed analyses using time-resolved identification protocols is described. To carry out this work, a NIR time-resolved confocal imager was constructed to read fluorescence signatures from the arrays. The device utilized a 780-nm pulsed diode laser, a single-photon avalanche diode (SPAD), and a high-numerical-aperture microscope objective mounted in an epi-illumination format. Due to the small size of the components that are required to construct this imager, the entire detector could easily be mounted on high-resolution translational stages and scanned over the stationary arrays. The instrument response function of the device was determined to be 275 ps (fwhm), which is adequate for measuring fluorophores with subnanosecond lifetimes. To characterize the system, NIR dyes were deposited directly on different substrate materials typically used for DNA microarrays, and the fluorescence lifetimes of two representative dyes were measured. The fluorescence lifetime for aluminum tetrasulfonated naphthalocyanine was found to be 1.92 ns, and a value of 1.21 ns was determined for the tricarbocyanine dye, IRD800, when it was deposited onto poly(methyl methacrylate) (PMMA) and measured in the dry state. Finally, the imager was used to monitor hybridization events using probe oligonucleotides chemically tethered to a PMMA substrate via a glutardialdehyde linkage to an aminated-PMMA surface. The limit of detection for oligonucleotides containing a NIR fluorescent reporter was determined to be 0.38 molecules/microm2, with this detection limit improving by a factor of 10 when a time-gate was implemented. Fluorescence lifetime analysis of the hybridization events on PMMA indicated a lifetime value of 1.23 ns for the NIR-labeled oligonucleotides when using maximum-likelihood estimators.

Cardiac observations late after operative transmyocardial laser "revascularization".

This case study suggests that transmyocardial laser revascularization does not produce lasting benefit.

Comparison of age, gender, number of aortic valve cusps, concomitant coronary artery bypass grafting, and magnitude of left ventricular-systemic arterial peak systolic gradient in adults having aortic valve replacement for isolated aortic valve stenosis.

Correlation of the structure of the operatively excised aortic valve with various clinical variables has received relatively little attention. This report describes certain observations in 115 patients aged >30 years (mean age 70) who had aortic valve replacement for aortic valve stenosis unassociated with mitral valve dysfunction. The operatively excised aortic valve was congenitally unicuspid in 3 patients (3%), congenitally bicuspid in 54 patients (47%), tricuspid in 57 patients (50%), and of uncertain structure in 1. Of the 87 patients (76%) aged > or =65 years (Medicare population), 36 (41%) had congenitally malformed valves (bicuspid in each), and of the 28 patients (24%) aged <65 years, 21 (75%) had congenitally malformed valves. A higher percentage of patients with congenitally malformed valves had peak systolic pressure gradients across the valve >50 mm Hg than did patients with tricuspid valves (57% vs 43%). Concomitant coronary artery bypass grafting (CABG) was performed in 52 patients (45%) (34 men and 18 women), and they had average peak systolic pressure gradients across the valve significantly lower than patients without coronary bypass (46 vs 64 mm Hg): 39% of the 57 patients with congenitally malformed valves and 53% of the 57 patients with tricuspid valves had concomitant coronary bypass (insignificant difference). Thus, in a relatively older population of 115 patients having aortic valve replacement for isolated aortic valve stenosis, with or without associated aortic regurgitation, one half had congenitally malformed valves (either unicuspid or bicuspid valves) and one half had tricuspid valves. Patients having concomitant CABG had significantly smaller gradients across the stenotic valves than those who had no CABG.

Four-laboratory validation study of the determination of chloramphenicol in veal calf urine.

A four-laboratory validation study of a method for the quantitation and confirmation of low part-per-billion levels of chloramphenicol extracted from veal calf urine was done. With this method, chloramphenicol, derivatized to the bis(trimethylsilyl)ether, was quantitated by gas chromatography with electron capture detection (GC-ECD) and confirmed by selected-ion monitoring in a negative ion chemical ionization gas chromatograph-mass spectrometer (GC-NICI-MS). Four analysts from 4 laboratories participated in the portion of the study devoted to chloramphenicol quantitation. Every analyst analyzed 5 sets, one set per day, on 5 different days. Each set included 6 samples consisting of a blank, 2 fortified samples, 2 incurred urine samples, and one duplicate. Thus, each analyst worked on a total of 30 samples. Chloramphenicol concentrations ranged from 0 to 9.7 ppb. All data were reported to 0.1 ppb. Coefficients of variation for distribution, CVd, ranged from 8.82 to 14.14% and for precision, CVr, ranged from 9.15 to 14.80%. Three analysts from 3 laboratories also participated in the confirmatory portion of the study, which was carried out to test whether the NICI-MS method developed earlier for higher concentrations of chloramphenicol and for an extract of muscle tissue could be applied to lower levels of chloramphenicol and to an extract prepared from urine. The extracts of 10 of the 30 samples were designated for confirmation only, but were obtained by the same procedure as extracts used for the quantitation part of the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of clenbuterol in cattle, sheep, and swine tissues by electron ionization gas chromatography/mass spectrometry.

A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid-liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 Cl). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 +/- 6.6% for liver tissues across all 3 species and 67.1 +/- 3.8% for muscle tissue across all 3 species.

Multiresidue assay for benzimidazole anthelmintics by liquid chromatography and confirmation by gas chromatography/selected-ion monitoring electron impact mass spectrometry.

A multiresidue method utilizing all-disposable labware has been developed for 8 benzimidazole anthelmintics from ovine, bovine, and swine muscle and liver tissues. After an initial extraction with ethyl acetate and subsequent evaporation, a 3-component extraction using hexane, ethanol, and 0.2N HCl was used for final cleanup. Clean extracts were produced for separation and determination by reverse-phase liquid chromatography at 298 nm, using methanol and aqueous buffer as mobile phase. A synthesized internal standard, 2-(n-butylmercapto)benzimidazole, was used for quantitation of all drugs. Results are included along with statistical information verifying the performance of the method. Spiked control tissues and incurred drug tissues were used for an intralaboratory study with a concentration range of 50-1470 ppb. A series of standard curves at 0, 50, 100, and 200 ppb were analyzed. Overall recovery at the 100 ppb level averaged 92% (CV 8%) in liver tissues, across all 3 species and 88% (CV 5%) in muscle tissues across all 3 species. Results were confirmed by gas chromatography/mass spectrometry with acid hydrolysis of the remaining extract in 2N HCl followed by re-extraction of the amine and derivatization to the tert-butyldimethylsilyl derivative. The anthelmintics were identified by gas chromatography/selected ion monitoring electron-impact mass spectrometry. Ion ratio measurements were taken and compared to standard material. CVs averaged 10% or less for all drugs tested.

The evaluation of a haemoperfusion device in conscious dogs.

A newly designed charcoal haemoperfusion device was evaluated by repeated haemoperfusion of conscious dogs. The procedure was tolerated well and the incidence of side effects was low. Alterations to haematology were small with platelet drops of only 9% and only minor disturbances to plasma chemistry were seen.

The pathogenesis of dialysis dementia.

There has been a recent increase in the number of literature reports describing a severe neurological syndrome (Dialysis Dementia) seen in a small number of dialysis patients. This article reviews the current literature on the disease and its possible causes.