Population increase and changes in behavior and morphology in the Critically Endangered Redonda ground lizard (Pholidoscelis atratus) following the successful removal of alien rats and goats

Redonda is a small volcanic Caribbean island that is home to at least 4 endemic lizard species, including the Critically Endangered ground lizard (Pholidoscelis atratus). Black rats (Rattus rattus) and domestic goats (Capra hircus) were introduced to the island at some time after its discovery by Europeans in the late 1500s. They had a devastating effect on the island, resulting in the loss of nearly all trees and most of the ground vegetation. Point count surveys of P. atratus in 2012 indicated low densities, and the invasive rats were observed hunting and preying on the lizards. Both populations of rats and goats were successfully removed in 2017 as part of an ecological restoration program, and native vegetation and invertebrate populations have increased rapidly since. Population surveys in 2017, 2018, and 2019 show the lizard population has increased by more than sixfold. In 2017, as rats and goats were being removed, we evaluated the morphology and escape behavior of this species and repeated these measurements 1 year later. We observed that P. atratus had become bolder, with a reduced flight distance. We also detected changes in limb morphology related to locomotion and suggest possible explanations that will need to be further investigated in the future. These results show how the removal of invasive species can rapidly affect lizard population recovery and behavior, potentially restoring island ecosystems to their pre-human interference dynamics.     

Long‐term outcomes with conventional fractionated and stereotactic radiotherapy for suspected heart‐base tumours in dogs

Published radiotherapy results for suspected heart‐based tumours in dogs are limited. In this retrospective longitudinal study (3/2014‐2019), eight dogs with either clinical signs attributable to a heart‐base mass (6), or asymptomatic with a progressively larger mass on echocardiogram (2), received conventional fractionated radiotherapy (CFRT) or stereotactic body radiotherapy (SBRT). Clinical findings in symptomatic cases included one or more of the following: retching/coughing (4), exercise intolerance (2), collapse (1), pericardial effusion (2), rare ventricular premature contractions (2), abdominal effusion (1), or respiratory distress due to chylothorax (1). CFRT cases received 50 Gray (Gy) in 20 fractions and SBRT cases received 30 Gy in 5 or 24 Gy in three fractions. Two dogs received chemotherapy post‐radiation. At analysis, 7/8 dogs were deceased and one was alive 684 days post‐treatment. The estimated median overall survival (MOS) from first treatment was 785 days (95% CI 114‐868 days, [range 114‐1492 days]). Five dogs received CFRT (MOS 817 days; (95% CI 155 days‐not reached [range 155‐1492 days])). Three dogs received SBRT with one alive at analysis (MOS 414 days, (95% CI, 114 days‐not reached [range 114‐414 days])). No statistically significant difference was found between survival for CFRT and SBRT. Of the symptomatic patients, 5/6 showed improvement. Mass size reduced in 4/5 cases receiving follow‐up ultrasounds. Possible complications included asymptomatic radiation pneumonitis (4), atrial tachycardia/premature beats (4) and pericardial effusion with heart failure coincident with tumour progression (1). This study provides preliminary evidence that radiotherapy may impact clinically relevant or progressively enlarging heart‐base masses.     

Triggers for use, optimal dosing, and problems associated with red cell transfusions.

The administration of RBC components can dramatically improve tissue oxygenation in small animals with symptomatic anemia and can be life saving. This therapy is not without risk, however. Careful consideration of the transfusion trigger, appropriate screening of the donor and recipient, and selection of the optimal RBC component and dose on an individual patient basis can help to limit the occurrence of adverse transfusion-related events. Appropriate component administration techniques, careful monitoring of recipients for the development of transfusion reactions, and prompt recognition and treatment of transfusion reactions are also essential in assuring safe transfusion practice.     

USE OF COMPUTED TOMOGRAPHY RENAL ANGIOGRAPHY FOR SCREENING FELINE RENAL TRANSPLANT DONORS

Preoperative knowledge of the renal vascular anatomy is important for selection of the appropriate feline renal donor. Intravenous urograms (IVUs) have been performed routinely to screen potential donors at the Veterinary Hospital of the University of Pennsylvania (VHUP), but the vascular phase views lack sufficient detail of the renal vascular anatomy. Computed tomography angiography (CTA), which requires a helical computed tomography (CT) scanner, has been found to provide superior renal vascular anatomic information of prospective human renal donors. The specific aims of this study were as follows: 1) develop the CTA technique for the feline patient; and 2) obtain preliminary information on feline renal vessel anatomy in potential renal donors. Ten healthy, potential feline renal donors were anesthetized and imaged using a third-generation helical CT scanner. The time delay between i.v. contrast medium injection and image acquisition, and other parameters of slice collimation, slice interval, pitch, exposure settings, and reconstruction algorithms were varied to maximize contrast medium opacification of the renal vascular anatomy. Optimal CTA acquisition parameters were determined to be: 1) 10-sec delay post-i.v. bolus of iodinated contrast medium; 2) two serially acquired (corresponding to arterial and venous phases) helical scans through the renal vasculature; 3) pitch of 2 (4 mm/sec patient translation, 2 mm slice collimation); and 4) 120-kVp, 160-mA, and 1-sec exposure settings. Retrospective reconstructed CTA transverse images obtained at a 2-mm slice width and a 1-mm slice interval in combination with two-dimensional reformatted images and three-dimensional reconstructed images were qualitatively evaluated for vascular anatomy; vascular anatomy was confirmed at surgery. Four cats had single renal arteries and veins bilaterally; four cats had double renal veins. One cat had a small accessory artery supplying the caudal pole of the left kidney. One cat had a left renal artery originating from the aorta at a 90 degrees angle with the cranial mesenteric artery. CTA of the feline renal vascular anatomy is feasible, and reconstruction techniques provide excellent anatomic vascular detail. CTA is now used routinely at VHUP to screen all potential feline renal donors.     

Acute pancreatitis in dogs

Objective: To summarize current information regarding severity assessment, diagnostic imaging, and treatment of human and canine acute pancreatitis (AP). Human‐based studies: In humans, scoring systems, advanced imaging methods, and serum markers are used to assess the severity of disease, which allows for optimization of patient management. The extent of pancreatic necrosis and the presence of infected pancreatic necrosis are the most important factors determining the development of multiple organ failure (MOF) and subsequent mortality. Considerable research efforts have focused on the development of inexpensive, easy, and reliable laboratory markers to assess disease severity as early as possible in the course of the disease. The use of prophylactic antibiotics, enteral nutrition, and surgery have been shown to be beneficial in certain patient populations. Veterinary‐based studies: The majority of what is currently known about naturally occurring canine AP has been derived from retrospective evaluations. The identification and development of inexpensive and reliable detection kits of key laboratory markers in dogs with AP could dramatically improve our ability to prognosticate and identify patient populations likely to benefit from treatment interventions. Treatment remains largely supportive and future studies evaluating the efficacy of surgery, nutritional support and other treatment modalities are warranted. Data sources: Current human and veterinary literature. Conclusions: Pancreatitis can lead to a life‐threatening severe systemic inflammatory condition, resulting in MOF and death in both humans and dogs. Given the similarities in the pathophysiology of AP in both humans and dogs, novel concepts used to assess severity and treat people with AP may be applicable to dogs.     

Reflectins: the unusual proteins of squid reflective tissues

A family of unusual proteins is deposited in flat, structural platelets in reflective tissues of the squid Euprymna scolopes. These proteins, which we have named reflectins, are encoded by at least six genes in three subfamilies and have no reported homologs outside of squids. Reflectins possess five repeating domains, which are highly conserved among members of the family. The proteins have a very unusual composition, with four relatively rare residues (tyrosine, methionine, arginine, and tryptophan) comprising approximately 57% of a reflectin, and several common residues (alanine, isoleucine, leucine, and lysine) occurring in none of the family members. These protein-based reflectors in squids provide a marked example of nanofabrication in animal systems.     

Crystal structure of the potassium channel KirBac1.1 in the closed state

The KirBac1.1 channel belongs to the inward-rectifier family of potassium channels. Here we report the structure of the entire prokaryotic Kir channel assembly, in the closed state, refined to a resolution of 3.65 angstroms. We identify the main activation gate and structural elements involved in gating. On the basis of structural evidence presented here, we suggest that gating involves coupling between the intracellular and membrane domains. This further suggests that initiation of gating by membrane or intracellular signals represents different entry points to a common mechanistic pathway.     

Temperature sex reversal implies sex gene dosage in a reptile

Sex in reptiles is determined by genes on sex chromosomes or by incubation temperature. Previously these two modes were thought to be distinct, yet we show that high incubation temperatures reverse genotypic males (ZZ) to phenotypic females in a lizard with ZZ and ZW sex chromosomes. Thus, the W chromosome is not necessary for female differentiation. Sex determination is probably via a dosage-sensitive male-determining gene on the Z chromosome that is inactivated by extreme temperatures. Our data invite a novel hypothesis for the evolution of temperature-dependent sex determination (TSD) and suggest that sex chromosomes may exist in many TSD reptiles.