Appraisal of the ‘penumbra effect’ using lingual pulse oximetry in anaesthetized dogs and cats

ObjectiveFactors described as contributors to the ‘penumbra effect’ in relation to pulse oximetry include optical shunting, circulatory anastomoses and probe parallelity. This study aimed to clarify the main underlying mechanism involved.Study designProspective clinical trial.AnimalsA total of 30 dogs and 15 cats (client-owned).MethodsIn anaesthetized dogs and cats, a pulse oximeter probe was placed on the tongue to measure haemoglobin oxygen saturation (SpO₂) and perfusion index. In 15 dogs, the probe was positioned at the root (baseline) of the tongue, then at 0.5 and 1 cm rostral to it, to investigate the effect of circulatory anastomoses on SpO₂ values. In cats (which do not have lingual arteriovenous anastomoses), the probe was positioned at the root and apex of the tongue. To assess the effect of probe parallelity on SpO₂ values in dogs, two lines were drawn parallel to the planes of the light-emitting diode and the detector surfaces and the intersection angle calculated using ImageMeter Pro, Google Play. In a further 15 dogs, the probe was placed at the tongue edge (0% optical shunt), with 50% optical shunt, then with the 50% optical shunt shielded. Data were analysed using Friedman’s test, Student t test and Pearson’s correlation coefficient (p < 0.05).ResultsIn dogs, SpO₂ values were significantly higher at 1.0 cm than at baseline (p < 0.0001). In cats, there were no significant differences in SpO₂ values at each location. There was no significant difference in SpO₂ between 0% and 50% optical shunt in dogs. SpO₂ had a moderate negative correlation with tongue thickness and negligible correlation with intersection angle.Conclusions and Clinical relevanceCirculatory anastomoses are probably responsible for observed changes in SpO₂ as the probe is placed towards an extremity, rather than optical shunting or probe parallelity.     

Increased levels of the 14-3-3 η and γ proteins in the synovial fluid of dogs with unilateral cranial cruciate ligament rupture

The present study investigated whether the 14-3-3 η and γ proteins, which are potent matrix metalloprotease (MMP) stimulators, are detectable in the synovial fluid of dogs with cranial cruciate ligament rupture (CCLR). Synovial fluid samples from 7 dogs with unilateral CCLR and control samples from 4 dogs without a history of any joint inflammation or any other abnormalities underwent Western blot analysis for the 14-3-3 η, γ, and σ proteins as well as MMP-1 and MMP-3. Craniocaudal and lateral radiographic projections of the stifle joint were evaluated for the presence and severity of 13 specific radiographic markers of osteoarthritis and graded numerically. The Spearman method was used to detect any correlation between the 14-3-3-η level in the synovial fluid and the radiograph-based grade. The η isoform was present only in the samples from the dogs with CCLR. The levels of 14-3-3-γ, MMP-1, and MMP-3 were significantly higher in the samples from the dogs with CCLR than in the control samples (P < 0.05). However, there was no significant difference between the CCLR and control samples in the level of the σ isoform. The Spearman method showed a significant correlation between the 14-3-3-η level in the synovial fluid and the presence of either patellar osteophytes or lateral or medial (or both) condylar periarticular osteophytes (P < 0.05). The MMP stimulatory effect of the 14-3-3 η and γ isoforms may be the reason for the high levels of MMP-1 and MMP-3 observed. Thus, 14-3-3 proteins, especially the η isoform, may be important markers of osteoarthritis caused by CCLR.     

Prediction of superovulatory response in Japanese Black cattle using ultrasound, plasma anti-Müllerian hormone concentrations and polymorphism in the ionotropic glutamate receptor AMPA1/GRIA1

The aim of this study was to improve the reliability of predicting the superovulatory response in Japanese Black cattle. Follicle counts and plasma anti-Müllerian hormone concentrations were analyzed within four days prior to the initiation of superovulation. The single nucleotide polymorphism (guanine or adenine) of the ionotropic glutamate receptor AMPA1 was determined. The plasma anti-Müllerian hormone concentration was positively correlated (P<0.001) with the numbers of all follicles and small (<5 mm) follicles and with the numbers of ova/embryos (P<0.001), fertilized embryos (P<0.001) and transferable embryos (P=0.005). There was no significant difference in follicle counts and superovulatory responses between donor cows bearing guanine/adenine or guanine/guanine alleles of AMPA1. Donor cows with a high plasma anti-Müllerian hormone concentration and homozygous for the guanine-containing allele of AMPA1 were most responsive to superovulation. The results suggest that physiological and genetic markers of superovulation have a synergistic effect on the accuracy of predictions of responsiveness.