Fluorine‐18 fluorodeoxyglucose positron emission tomography imaging exhibits increased SUVmax at the level of the spinal intumescence in normal dogs

Positron emission tomography (PET) imaging utilizing fluorine‐18 labeled fluorodeoxyglucose is a relatively new imaging modality in veterinary medicine that is becoming more common for oncological staging and for musculoskeletal imaging. Thus, it is important to identify the normal variations on PET imaging that may be mistaken for pathology. Variation in standardized uptake values (SUVmax) have been anecdotally identified in the spinal cord of dogs undergoing fluorodeoxyglucose (FDG) PET–CT examinations for oncological staging, with notable increase in SUVmax values identified in the region of the cervical and lumbar spinal intumescences. The aim of this retrospective, analytical study was to compare the SUVmax values at four different locations throughout the spinal cord (C3, C5‐T1, T13, and L3‐S1) of a group of dogs with no evidence of neurologic disease and compare those findings to histologic specimens from dogs euthanized for unrelated disease. SUVmax values were significantly higher at the cervical and lumbar intumescences in comparison to the control regions (P < .0001 and P < .0001, respectively). Neuronal count and spinal cord gray matter area were also significantly greater at the cervical and lumbar intumescences (neuronal count P = .0025 and P = .0001; area P = .0004 and P = .0009, respectively) while overall neuronal density was lower (P = .003 and P = .028, respectively). We presume the increased SUVmax values at the spinal cord intumescences are the result of overall increased neuron count, increased proportion of gray matter, and increased spinal cord gray matter area. These findings will aid in the interpretation of future PET–CT studies and hopefully prevent the misdiagnosis of spinal cord disease in normal canines.     

Differential Expression of IGF Family Members in Heat‐Stressed Embryos Produced In Vitro from OPU‐Derived Oocytes of Nelore (Bos indicus) and Holstein (Bos taurus) Cows

The IGF system is related to embryo quality. We aim to determine the effect of the heat stress on the mRNA expression of IGF1 and IGF2, IGFR1 and IGFR2, IGFBP2 and IGFBP4, and PAPPA in in vitro production (IVP) blastocysts from Nelore and Holstein after ovum pick up (OPU) to better understand the differences between these breeds. Oocytes from four Nelore and seven Holstein were collected in six OPU sessions. Following in vitro maturation and fertilization using six Nelore or Holstein sires, embryos were divided into control (cultured at 39°C) and heat stress (HS; exposed to 41°C for 9 h). Blastocysts were submitted to RNA extraction. The IGF1 expression was higher in blastocysts under HS in both breeds, and the expression of IGFBP2 and IGFBP4 was higher in Holstein blastocysts under HS. The high PAPPA expression and the low expression of IGFBP2 and IGFBP4 are associated with a more efficient degradation of IGFBPs, which results in greater IGF bioavailability in Nelore blastocysts and may contribute to the superior HS tolerance in Nelore, when compared to Holstein.     

Amyloid-beta dynamics correlate with neurological status in the injured human brain

The amyloid-beta peptide (Abeta) plays a central pathophysiological role in Alzheimer's disease, but little is known about the concentration and dynamics of this secreted peptide in the extracellular space of the human brain. We used intracerebral microdialysis to obtain serial brain interstitial fluid (ISF) samples in 18 patients who were undergoing invasive intracranial monitoring after acute brain injury. We found a strong positive correlation between changes in brain ISF Abeta concentrations and neurological status, with Abeta concentrations increasing as neurological status improved and falling when neurological status declined. Brain ISF Abeta concentrations were also lower when other cerebral physiological and metabolic abnormalities reflected depressed neuronal function. Such dynamics fit well with the hypothesis that neuronal activity regulates extracellular Abeta concentration.     

Freezing equine semen: the effect of combinations of semen extenders and glycerol on post-thaw motility

Objective   We evaluated combinations of two commercial semen extenders and three concentrations of glycerol to determine the combination that yielded the highest post-thaw sperm motility.
Design   A randomised 2 × 3 block design was used.
Procedure   Semen was collected from four stallions (6 collections per stallion). The sample was diluted with either a dried skim-milk glucose extender (EZ Mixin Original Formula) or a chemically defined, milk-free diluent (INRA 96), and each was used in combination with 2%, 3% or 4% glycerol in standard commercial freezing medium. Sperm motility was assessed by microscopy in fresh and post-thaw semen.
Results   There was a significant difference between the two extenders in the motility of spermatozoa after cryopreservation (48.9% for INRA 96; 38.6% for EZ Mixin OF; P < 0.0001). Glycerol at 4% in freezing medium yielded the highest post-thaw motility, significantly better than 2% ( P < 0.05). Three of four stallions had significantly higher post-thaw motility using INRA 96 relative to EZ Mixin OF ( P < 0.01), and two of four stallions had significantly higher post-thaw motility using 4% glycerol ( P < 0.05). The combination of INRA 96 and 4% glycerol in freezing medium gave the highest average post-thaw motility of 51.5%.
Conclusion   In this study, INRA 96 combined with 4% glycerol yielded an average recovery of progressively motile sperm consistently above the 35% target.