Steady-state response characteristics of a pulse oximeter on equine intestine

The steady-state response characteristics of a pulse oximeter were evaluated on intestinal segments of seven clinically normal halothane-anesthetized horses. Arterial oxygen tension greater than 200 mm of Hg, end tidal carbon dioxide from 30 to 35 mm of Hg, and systemic mean arterial pressure greater than 70 mm of Hg were maintained throughout the recording periods. Values for percentage of pulse oximeter oxygen saturation, pulsatile blood flow, and percentage of signal strength were recorded from jejunum, ileum, cecum, left ventral colon, left dorsal colon, and descending colon. Probe placement on intestinal segments was recorded as over or not over visible subserosal or transmural vessels. There was no significant difference between median values on the basis of vessel codes for pulse oximeter oxygen saturations, pulsatile flow, and signal strength. Median values recorded for pulse oximeter oxygen saturation were 93% from jejunum and ileum and 95% from cecum, left ventral colon, left dorsal colon, and descending colon; median values for pulsatile flow were 576 from jejunum, 560 from ileum, 560 from cecum, 574 from left ventral colon, 578 from left dorsal colon, and 560 from descending colon; median values for signal strength were 50% from jejunum, 67.5% from ileum, 60% from cecum, 75% from left ventral colon, 50% from left dorsal colon, and 52.5% from descending colon. Median values obtained from each anatomic location were not significantly different for pulsatile flow or signal strength. Median pulse oximetry oxygen values recorded from jejunum and ileum were significantly lower than values obtained from other intestinal segments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Population Dynamics of Small Rodents in Farm Buildings and on Arable Land1

Live-capture/recapture data on house mice caught in buildings on a single farm in England over a 1-year period showed that the populations were essentially unstable, being characterized by constant changes in size and composition. Less than 50% of the mice were recovered 8 weeks after they had been first captured. Although there was considerable individual variation in the movements of male and of female mice within particular buildings, movement between isolated populations was rare (6/439 animals; 1.4%). The house mouse was also found to be present in hedgerows near and distant to the farm buildings, albeit in low number. Movements of out-door living mice into farm buildings were not extensive, but could be important in relation to the re-invasion of cleared premises. The most abundant small rodent in the hedgerows was found to be Apodemus sylvaticus (L.).     

Serially determined plasma alpha-tocopherol concentrations and results of the oral vitamin E absorption test in clinically normal horses and in horses with degenerative myeloencephalopathy

Plasma alpha-tocopherol (vitamin E) values were monitored serially in 9 foals sired by a stallion with equine degenerative myeloencephalopathy (EDM) and in 5 age-matched control foals (sired by a clinically normal stallion) raised in the same environment for the first year of life. Clinical evaluation determined that 8 of the 9 foals sired by the stallion with EDM had neurologic deficits consistent with the disease on one or more occasions during the study period, whereas control foals had normal gait. From 6 weeks to 10 months of age, plasma alpha-tocopherol values in foals with signs of EDM were significantly (P less than 0.001) lower than those in control foals. An oral vitamin E absorption test was performed, and results for 8 of the affected horses and the affected stallion were compared with results for 4 of the monitored control horses and 4 additional control horses. Significant differences were not evident in any of the absorption indices. On the basis of data from this study and supported by reported prophylactic and therapeutic benefits of supplemented vitamin E, low plasma concentration of vitamin E is concluded to be a factor in the development of EDM in the first year of life of hereditarily predisposed foals. It was also concluded that the significantly lower alpha-tocopherol values seen in the foals in this study did not reflect a primary gastrointestinal tract absorption problem.     

Antibody Response in Sheep Following Immunization with Streptococcus bovis in Different Adjuvants

Recent studies have shown that immunization with Streptococcus bovis using Freund's complete adjuvant (FCA) may confer protection against lactic acidosis in sheep. The major objective of this study was to compare the antibody responses to S. bovis in a practically acceptable adjuvant (Freund's incomplete adjuvant (FIA); QuilA; dextran sulphate (Dex); Imject Alum; or Gerbu) and in FCA. Thirty-five sheep were randomly allocated to 7 treatment groups. Six groups were immunized with S. bovis in an adjuvant; the other group served as the non-immunization control. The primary immunization was administered intramuscularly on day 0, followed by a booster injection on day 28. Immunization with FCA induced the highest saliva and serum antibody responses. The saliva antibody concentrations in the FIA and QuilA groups were significantly higher than those in the Alum, Dex and Gerbu groups (p<0.01). The serum antibody concentration in the FIA group was significantly higher than those in the QuilA, Alum, Dex and Gerbu groups (p<0.01). Immunization enhanced the antibody level in faeces (p<0.05), but there was no significant difference between the different adjuvant groups (p>0.05). Seven and 14 days following booster immunization, the saliva antibody levels induced by QuilA and/or FIA were comparable with the level stimulated by FCA (p>0.05). There was a strongly positive correlation (R ² = 0.770, p<0.01) between the antibody concentrations in saliva and serum. Compared with the controls, a higher faecal dry matter content was observed in the animals immunized with either FCA or QuilA. The change in faecal dry matter content was positively associated with the faecal antibody concentration (R ² = 0.441, p<0.05). These results indicate that FIA and QuilA were effective at inducing high levels of antibody responses to S. bovis, and suggest that either Freund's incomplete adjuvant or QuilA may be useful for preparing a practically acceptable vaccine against lactic acidosis.     

Improved detection of Mycobacterium avium subsp. paratuberculosis In milk by immunomagnetic PCR

The potential use of a novel immunomagnetic PCR (IMS-PCR) technique as a rapid method to screen milk samples for the presence of Mycobacterium avium subsp. paratuberculosis (M. ptb) was assessed. Immunomagnetic separation (IMS) for M. ptb, developed at Queen's University, Belfast, was applied to milk samples prior to IS900 PCR in order to selectively concentrate any M. ptb cells present and, at the same time, separate the cells from constituents of milk likely to inhibit subsequent PCR. This increased the sensitivity of IS900 PCR. IMS-PCR sensitivity could be further increased by initial centrifugation (2500 g for 20 min) of larger volumes of milk (10 and 50 ml), and resuspension of the sediment into a 1 ml volume appropriate for IMS treatment. Following IMS, template DNA for IS900 PCR was obtained by heating the bead-cell suspension in a thermal cycler at 100 degrees C for 15 min. It was estimated that the IMS-PCR assay could detect approximately 10(3)CFU of M. ptb per 50 ml of milk (equivalent to 20 CFU/ml), whereas the minimum detection limit of direct IS900 PCR was estimated at 10(5)CFU of M. ptb per 50 ml (equivalent to 2000 CFU/ml). A blind trial was carried out in which a total of 40 spiked (10(6)CFU M. ptb) and unspiked, raw and laboratory-pasteurised milk samples were independently tested by IMS-PCR and conventional IS900 PCR. IMS-PCR correctly identified 97. 5% of milk samples (sensitivity 100%, specificity 95%), including spiked milk samples before and after laboratory-pasteurisation. One false positive result was obtained which may have resulted from carryover between samples during the IMS procedure. Conventional IS900 PCR correctly identified only 72.5% of the same 40 milk samples (sensitivity 23%, specificity 100%). IMS-PCR was also shown to be capable of detecting natural M. ptb infection in raw sheep's milk, and raw and commercially pasteurised cows' milk.