Extinct (129)I in halite from a primitive meteorite: evidence for evaporite formation in the early solar system

Halite crystals from the Zag H3-6 chondrite contain essentially pure (monoisotopic) xenon-129 ((129)Xe) produced in the early history of the solar system by the decay of short-lived iodine-129 ((129)I) (half-life = 15.7 million years). Correlated release of (129)Xe and (128)Xe, produced artificially from (127)I by neutron irradiation, corresponds to an initial ((129)I/(127)I) ratio of (1.35 +/- 0.05) x 10(-4), close to the most primitive early solar system value. If the (129)Xe was produced by in situ decay, then the halite formed from an aqueous fluid within 2 million years of the oldest known solar system minerals.     

Rapid brain MRI protocols result in comparable differential diagnoses versus a full brain protocol in most canine and feline cases

Evaluation of brain disease in veterinary patients uses a wide variety of MRI sequences. A shortened protocol that maintains consistency of interpretation would reduce radiologist reporting time, patient anesthetic time, and client cost. The aims of this retrospective, methods comparison, observer agreement study were to evaluate whether abbreviated MRI protocols alter differential diagnoses and recommendations compared to our institution's standard protocol; evaluate interobserver agreement on standard brain MRIs; and assess whether differential diagnoses change after postcontrast images. Normal and pathologic canine and feline brain MRIs were retrieved from hospital archives. Three protocols were created from each: a 5-sequence noncontrast enhanced Fast Brain Protocol 1 (FBP1); a 6-sequence contrast-enhanced Fast Brain Protocol 2 (FBP2); and an 11-sequence standard brain protocol (SBP). Three blinded veterinary radiologists interpreted FBP images for 98 cases (1 reader/case) and SBP images for 20 cases (3 readers/case). A fourth observer compared these interpretations to the original MRI reports (OMR). Overall agreement between FBPs and OMR was good (k = 0.75) and comparable to interobserver agreement for multiple reviews of SBP cases. Postcontrast images substantially altered conclusions in 17/97 cases (17.5%), as well as improved interobserver agreement compared to noncontrast studies. The conclusions reached with shortened brain protocols were comparable to those of a full brain study. The findings supported the use of a 6-sequence brain MRI protocol (sagittal T2-weighted [T2w] TSE; transverse T2w turbo spin echo fluid-attenuated inversion recovery, T2*-weighted gradient recalled echo, T1-weighted spin echo, and diffusion weighted imaging/apparent diffusion coefficient; and postcontrast transverse T1-weighted spin echo) for dogs and cats with suspected intracranial disease.     

Active bleb formation is abated in Lytechinus variegatus red spherule coelomocytes after disruption of acto‐myosin contractility

Red spherule coelomocytes are immune cells in the sea urchin Lytechinus variegatus that have been characterized as motile O₂ transport cells. Video microscopy of living red spherule coelomocytes reveals a constitutive, dynamic array of cellular morphologies and movements. Cells continuously send out and retract membrane blebs all over the cell surface as part of their normal cellular physiology. Disruption of microtubules by perfusion with either nocodazole or taxol had no effect on bleb formation or motility. Perfusion with cytochalasin B abated bleb formation and revealed cells that exhibited multiple small spheres attached by short membrane extensions. Attenuation of blebbing and intracellular organelle motility were restored by washing out with cytochalasin B. Treatment with phalloidin also abated bleb formation and revealed a smooth, spherical cellular morphology. The effects of phalloidin were completely reversible after washout. Red spherule coelomocytes treated with blebbistatin rounded up with an irreversible retraction of blebs into surface blebs that were greatly reduced in size, number and motility. Normal cell surface bleb formation and intracellular organelle motility were not restored after washout of the drug. These results indicate that the acto‐myosin contractile mechanism contributes to the dynamics of constitutive cell surface membrane blebbing in invertebrate immune cells.     

Detection, quantification, and pharmacokinetics of furosemide and its effects on urinary specific gravity following IV administration to horses

Furosemide is a potent loop diuretic used for the prevention of exercise-induced pulmonary hemorrhage in horses. This drug may interfere with the detection of other substances by reducing urinary concentrations, so its use is strictly regulated. The regulation of furosemide in many racing jurisdictions is based on paired limits of urinary SG (<1.010) and serum furosemide concentrations (>100 ng/ml). To validate this regulatory mechanism, a liquid chromatography/mass spectrometry/mass spectrometry method employing a solid-phase extraction procedure and furosemide-d5 as an internal standard was developed. The method was used to determine the pharmacokinetic parameters of furosemide in equine serum samples and its effects on urinary SG after IV administration (250 mg) to 10 horses. Pharmacokinetic analysis showed that serum concentrations of furosemide were well described by a two-compartmental open model. Based on results in this study, it is very unlikely for horses to have serum furosemide concentrations greater than 100 ng/ml or urine SG less than 1.010 at 4 hours after administration (250 mg IV). However, it should be remembered that urine SG is a highly variable measurement in horses, and even without furosemide administration, some horses might naturally have urine SG values less than 1.010.