The ctenophore Mnemiopsis leidyi is one of the most successful marine bioinvaders on record. Native to the Atlantic coast of the Americas, M. leidyi invaded the Black Sea, Caspian and Mediterranean ...Seas beginning the in late 1980s, followed by the North and Baltic Seas starting in 2006, with major concomitant alterations in pelagic ecology, including fishery collapses in some cases. Using extensive native range sampling (21 sites), along with 11 invasive sites in the Black, Caspian, Mediterranean, North and Baltic Seas, we examined M. leidyi worldwide phylogeographic patterns using data from mitochondrial cytochrome b (cytb) and six nuclear microsatellite loci. Cytb and microsatellite data sets showed different levels of genetic differentiation in the native range. Analyses of cytb data revealed considerable genetic differentiation, recovering three major clusters (northwestern Atlantic, Caribbean, and South America) and further divided northwestern Atlantic sampling sites into three groups, separated approximately at Cape Hatteras on the US Atlantic coast and at the Floridian peninsula, separating the Gulf of Mexico and Atlantic coasts. In contrast, microsatellite data only distinguished samples north and south of Cape Hatteras, and suggested considerable gene flow among native samples with clear evidence of isolation by distance. Both cytb and microsatellite data sets indicated that the northern invaders (North/Baltic Seas) originated from north of Cape Hatteras, with cytb data pointing to Delaware and north. Microsatellite data indicated a source for the southern invaders (Black, Caspian and Mediterranean Seas) to be south of Cape Hatteras, while cytb data narrowed the source location to the Gulf of Mexico region. Both cytb and microsatellite data sets suggested that the southern invasion was associated with genetic bottlenecks while evidence was equivocal for the northern invasion. By increasing the native range spatial sampling, our dataset was able to sufficiently characterize patterns and levels of genetic differentiation in the native range of M. leidyi and identify likely biogeographic boundaries, allowing for the most complete characterization of M. leidyi’s invasion histories and most realistic estimates of its source region(s) to date.
The present work aims to investigate the microstructure evolution along the length of a directionally solidified Al–8wt.%Ni hypereutectic alloy with a view to tailoring the range of microstructural ...parameters providing the best balance among tensile, wear, and corrosion properties. A macrostructure columnar region is shown to be associated with solidification cooling rates (
T
˙
) > 4.8 °C/s, having a microstructure typified by eutectic colonies (EC) of Al
3
Ni fibers + α-Al matrix. Differently, for
T
˙
< 4.8 °C/s, equiaxed grains prevailed consisting of the primary Al
3
Ni phase distributed in the EC matrix boundaries. A single diagram is proposed to relate experimental values of tensile, wear, and corrosion properties to each kind of microstructure (EC and Al
3
Ni + EC), exhibiting distinct behaviors, i.e., the Al–8wt.%Ni alloy with an EC microstructure is shown to provide higher tensile and wear resistances, whereas the best corrosion resistance and medium wear resistance can be assigned to the Al–8wt.%Ni alloy with an Al
3
Ni + EC microstructure.
Background
Progressive myelomalacia (PMM) is a catastrophic disease associated with acute intervertebral disc extrusion (IVDE). Published data on the clinical characteristics of this disease are ...limited.
Objective
To describe the onset and progression of clinical signs of PMM in a large case cohort.
Animals
Fifty‐one dogs, 18 with histopathologically confirmed PMM, 33 presumptively diagnosed based on clinical signs and diagnostic imaging.
Methods
Retrospective study. Dogs with confirmed IVDE and either a histopathologic diagnosis of PMM or a high clinical suspicion were identified by medical record search. Data on nature and progression of signs were extracted.
Results
Twenty‐four of 51 dogs were Dachshunds. T12–T13 was the most common site of disc extrusion (12 of 56), and 18 of 55 of mid‐to‐caudal lumbar discs (between L3 and L6) were affected. Onset of PMM signs ranged from present at first evaluation (17/51) to 5 days after presentation, with 25 of 51 cases developing signs within 48 hours. Progression of signs from onset of PMM to euthanasia or death, excluding 7 cases euthanized at presentation, ranged from 1 to 13 days with 23 being euthanized within 3 days. Nonspecific systemic signs were documented in 30 of 51 dogs.
Conclusion and Clinical Importance
The majority of dogs developed PMM within 2 days of presentation and was euthanized within another 3 days. However, onset can be delayed up to 5 days after presentation with progression to euthanasia taking as long as 2 weeks. Mid‐to‐caudal lumbar discs might be associated with an increased risk of PMM.
In many marine fish species, genetic population structure is typically weak because populations are large, evolutionarily young and have a high potential for gene flow. We tested whether genetic ...markers influenced by natural selection are more efficient than the presumed neutral genetic markers to detect population structure in Atlantic herring (Clupea harengus), a migratory pelagic species with large effective population sizes. We compared the spatial and temporal patterns of divergence and statistical power of three traditional genetic marker types, microsatellites, allozymes and mitochondrial DNA, with one microsatellite locus, Cpa112, previously shown to be influenced by divergent selection associated with salinity, and one locus located in the major histocompatibility complex class IIA (MHC-IIA) gene, using the same individuals across analyses. Samples were collected in 2002 and 2003 at two locations in the North Sea, one location in the Skagerrak and one location in the low-saline Baltic Sea. Levels of divergence for putatively neutral markers were generally low, with the exception of single outlier locus/sample combinations; microsatellites were the most statistically powerful markers under neutral expectations. We found no evidence of selection acting on the MHC locus. Cpa112, however, was highly divergent in the Baltic samples. Simulations addressing the statistical power for detecting population divergence showed that when using Cpa112 alone, compared with using eight presumed neutral microsatellite loci, sample sizes could be reduced by up to a tenth while still retaining high statistical power. Our results show that the loci influenced by selection can serve as powerful markers for detecting population structure in high gene-flow marine fish species.
BACKGROUND: Acute intervertebral disk herniation (IVDH) is a common cause of spinal cord injury in dogs and currently there is no proven medical treatment to counter secondary injury effects. Use of ...methylprednisolone sodium succinate (MPSS) or polyethylene glycol (PEG) as neuroprotectants is advocated but controversial because neither treatment has been tested in placebo‐controlled, randomized, blinded trials in dogs. HYPOTHESIS: Polyethylene glycol will improve the outcome of severe spinal cord injury caused by IVDH compared to MPSS or placebo. ANIMALS: Client‐owned dogs with acute onset of thoracolumbar IVDH causing paralysis and loss of nociception for <24 hours. METHODS: Dogs were randomized to receive MPSS, PEG, or placebo; drugs appeared identical and group allocation was masked. Drug administration was initiated once the diagnosis of IVDH was confirmed and all dogs underwent hemilaminectomy. Neurologic function was assessed 2, 4, 8, and 12 weeks postoperatively using an open field gait score (OFS) as the primary outcome measure. Outcomes were compared by the Wilcoxon rank sum test. RESULTS: Sixty‐three dogs were recruited and 47.6% recovered ambulation. 17.5% developed progressive myelomalacia but there was no association with group. There was no difference in OFS among groups. Although full study power was not reached, conditional power analyses indicated the futility of continued case recruitment. CONCLUSIONS: This clinical trial did not show a benefit of either MPSS or PEG in the treatment of acute, severe thoracolumbar IVDH when used as adjunctive medical treatment administered to dogs presenting within 24 hours of onset of paralysis.
Stereotactic radiosurgery (SRS) is a procedure that delivers a single large radiation dose to a well‐defined target. Here, we describe a frameless SRS technique suitable for intracranial targets in ...canines. Medical records of dogs diagnosed with a primary intracranial tumour by imaging or histopathology that underwent SRS were retrospectively reviewed. Frameless SRS was used successfully to treat tumours in 51 dogs with a variety of head sizes and shapes. Tumours diagnosed included 38 meningiomas, 4 pituitary tumours, 4 trigeminal nerve tumours, 3 gliomas, 1 histiocytic sarcoma and 1 choroid plexus tumour. Median survival time was 399 days for all tumours and for dogs with meningiomas; cause‐specific survival was 493 days for both cohorts. Acute grade III central nervous system toxicity (altered mentation) occurred in two dogs. Frameless SRS resulted in survival times comparable to conventional radiation therapy, but with fewer acute adverse effects and only a single anaesthetic episode required for therapy.
Candidates for transcatheter aortic valve implantation (TAVI) are currently evaluated using computed tomography angiography and invasive cardiac catheterization as an essential part of case selection ...and pre-procedure interventional planning. However, both imaging methods utilize iodinated agents, which may cause contrast-induced nephropathy, particularly in patients with baseline renal dysfunction. This study aimed to describe a zero-contrast imaging protocol for pre-TAVI evaluation in patients with advanced renal impairment.
The pre-TAVI zero-contrast scheme consisted of the following multi-modality combinations: (1) gadolinium-free magnetic resonance imaging (three-dimensional navigator-echo with electrocardiogram-gated steady-state free-precession series); (2) iodinated-free multislice computed tomography electrocardiogram-gated; (3) lower limb arterial duplex scan ultrasound; and (4) transesophageal echocardiography. Ultimately, TAVI was performed for those deemed good candidates, and contrast was allowed during the intervention; however, operators were strongly advised to utilize the least volume possible of iodinated agents. This pilot survey included ten patients with symptomatic aortic stenosis and renal dysfunction who underwent zero-contrast multi-modality imaging.
All the patients ultimately underwent TAVI. The intervention was successful in all cases, without ≥ moderate residual aortic regurgitation, prosthesis embolization, annulus rupture, major vascular complications, stroke, or death during index hospitalization. The creatinine clearance remained stable throughout the observation period (baseline: 26.85 ± 12.55 mL/min; after multi-modality imaging: 26.76 ± 11.51 mL/min; post-TAVI at discharge: 29.84 ± 13.98 mL/min;
= 0.3 all).
The proposed contrast-free imaging protocol appears to be a promising clinical tool for pre-TAVI evaluation in patients with severe renal dysfunction.
Group B Streptococcus (GBS) is a multiserotype bacterial pathogen representing a major cause of life-threatening infections in newborns. To develop a broadly protective vaccine, we analyzed the ...genome sequences of eight GBS isolates and cloned and tested 312 surface proteins as vaccines. Four proteins elicited protection in mice, and their combination proved highly protective against a large panel of strains, including all circulating serotypes. Protection also correlated with antigen accessibility on the bacterial surface and with the induction of opsonophagocytic antibodies. Multigenome analysis and screening described here represent a powerful strategy for identifying potential vaccine candidates against highly variable pathogens.
Background
Reports of histiocytic sarcoma (HS) involving the central nervous system (CNS) are sparse and consist mainly of case reports describing 1–3 animals.
Objective
The objective of this study ...was to report the signalments, clinical signs, clinicopathologic and diagnostic imaging findings, treatment, and outcome of a series of dogs with HS and CNS involvement.
Animals
Nineteen dogs with HS examined at veterinary referral hospitals.
Methods
Retrospective case series. Medical records were reviewed and cases with a histopathological diagnosis of CNS HS were included in the study. Diagnostic imaging studies of the CNS were evaluated and histopathologic samples were reviewed to confirm the diagnosis.
Results
Retrievers and Pembroke Welsh Corgis were overrepresented in this cohort of dogs. Tumors involved the brain in 14 dogs and the spinal cord in 5. In 4 dogs, HS was part of a disseminated, multiorgan process whereas it appeared confined to the CNS in 15 dogs. Diagnostic imaging had variable appearances although extraaxial masses predominated in the brain. There was meningeal enhancement in all dogs that was often profound and remote from the primary mass lesion. Pleocytosis was present in all dogs with CSF evaluation. Median survival was 3 days.
Conclusions and Clinical Importance
Breed predispositions appear to vary from reports of HS in other organ systems. Some unique imaging and clinicopathologic characteristics, particularly brain herniation, profound meningeal enhancement, and pleocytosis in combination with 1 or more mass lesions, might help to differentiate this neoplasm from others involving the CNS, although this requires further study.
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