Loss of Mhc and Neutral Variation in Peary Caribou: Genetic Drift Is Not Mitigated by Balancing Selection or Exacerbated by Mhc Allele Distributions

Theory and empirical results suggest that the rate of loss of variation at Mhc and neutral microsatellite loci may differ because selection influences Mhc genes, and because a high proportion of rare alleles at Mhc loci may result in high rates of loss via drift. Most published studies compare Mhc and microsatellite variation in various contemporary populations to infer the effects of population size on genetic variation, even though different populations are likely to have different demographic histories that may also affect contemporary genetic variation. We directly compared loss of variation at Mhc and microsatellite loci in Peary caribou by comparing historical and contemporary samples. We observed that similar proportions of genetic variation were lost over time at each type of marker despite strong evidence for selection at Mhc genes. These results suggest that microsatellites can be used to estimate genome-wide levels of variation, but also that adaptive potential is likely to be lost following population bottlenecks. However, gene conversion and recombination at Mhc loci may act to increase variation following bottlenecks

Quantifying inbreeding avoidance through extra-pair reproduction

© 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.Peer reviewedPublisher PD

First-in-man craniectomy and asportation of solitary cerebellar metastasis in COVID-19 patient: A case report

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak has an impact on the delivery of neurosurgical care, and it is changing the perioperative practice worldwide. We present the first case in the literature of craniectomy procedure and asportation of a solitary cerebellar metastasis of the oesophagus squamous carcinoma in a 77 years old woman COVID-19 positive. In these particular circumstances, we show that adequate healthcare resources and risk assessments are essential in the management of COVID-19 patients referred to emergency surgery. Presentation of case: The case here presented was treated in 2019 for squamous carcinoma of the oesophagus. In April 2020, she presented a deterioration of her clinical picture consisting of dysphagia, abdominal pain, hyposthenia and ataxia. A Head CT scan was performed, which showed the presence of a solitary cerebellar metastasis. Her associated SARS-CoV-2 positivity status represented the principal clinical concern throughout her hospitalisation. Discussion: The patient underwent a suboccipital craniectomy procedure with metastasis asportation. She tested positive for SARS-CoV-2 in the pre- and post-operative phases, but she was not admitted to the intensive care unit because she did not present any respiratory complications. Her vital parameters and inflammation indexes fell within the reference ranges, and she was kept in isolation for 16 days in our neurosurgical unit following strict COVID-19 measures. She was asymptomatic and not treated for any of the specific and non-specific symptoms of COVID-19. Conclusion: This is the first case reported of solitary cerebellar metastasis of oesophagus carcinoma operated on a COVID-19 positive patient. It shows that asymptomatic COVID-19 positive patients can undergo major emergency surgeries without the risk of infecting the operating team if adequate Personal Protection Equipment (PPE) is used. The patient remained asymptomatic and did not develop the disease's active phase despite undergoing a stressful event such as a major emergency neurosurgical procedure. In the current crisis, a prophylactic COVID-19 screening test can identify asymptomatic patients undergoing major emergency surgery and adequate resource planning and Personal Protective Equipment (PPE) for healthcare workers can minimise the effect of the COVID-19 pandemic

Demographic mechanisms of inbreeding adjustment through extra-pair reproduction

One hypothesis explaining extra-pair reproduction is that socially monogamous females mate with extra-pair males to adjust the coefficient of inbreeding (ƒ) of extra-pair offspring (EPO) relative to that of within-pair offspring (WPO) they would produce with their socially paired male. Such adjustment of offspring ƒrequires non-random extra-pair reproduction with respect to relatedness, which is in turn often assumed to require some mechanism of explicit pre-copulatory or post-copulatory kin discrimination.  We propose three demographic processes that could potentially cause mean ƒ to differ between individual females' EPO and WPO given random extra-pair reproduction with available males without necessarily requiring explicit kin discrimination. Specifically, such a difference could arise if social pairings formed non-randomly with respect to relatedness or persisted non-randomly with respect to relatedness, or if the distribution of relatedness between females and their sets of potential mates changed during the period through which social pairings persisted.  We used comprehensive pedigree and pairing data from free-living song sparrows (Melospiza melodia) to quantify these three processes and hence investigate how individual females could adjust mean offspring ƒ through instantaneously random extra-pair reproduction.  Female song sparrows tended to form social pairings with unrelated or distantly related males slightly less frequently than expected given random pairing within the defined set of available males. Furthermore, social pairings between more closely related mates tended to be more likely to persist across years than social pairings between less closely related mates. However, these effects were small and the mean relatedness between females and their sets of potential extra-pair males did not change substantially across the years through which social pairings persisted.  Our framework and analyses illustrate how demographic and social structuring within populations might allow females to adjust mean ƒ of offspring through random extra-pair reproduction without necessarily requiring explicit kin discrimination, implying that adjustment of offspring f might be an inevitable consequence of extra-pair reproduction. New theoretical and empirical studies are required to explore the general magnitude of such effects and quantify the degree to which they could facilitate or constrain long-term evolution of extra-pair reproduction

Variation in parent-offspring kinship in socially monogamous systems with extra-pair reproduction and inbreeding

ACKNOWLEDGMENTS We thank the Tsawout and Tseycum First Nations bands for allowing access to Mandarte; everyone who contributed to long-term data collection; Lukas Keller and Ryan Germain for helpful discussions; and the European Research Council, UK Royal Society, National Sciences and Engineering Research Council of Canada and Swiss National Science Foundation for their invaluable support. DATA ARCHIVING Data are available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.4r383.Peer reviewedPublisher PD

3-Tesla MR spectroscopy in patients subjected to bone marrow transplantation: clinical correlations.

PURPOSE: This study evaluated the usefulness of 3-Tesla magnetic resonance (MR) spectroscopy in patients with non-Hodgkin's lymphoma (NHL) undergoing bone marrow transplantation (BMT). MATERIALS AND METHODS: Twelve NHL patients who were candidates for BMT underwent three MR examinations of the lumbosacral spine: before ablative therapy for BMT, 15±4 days and 54±24 days after BMT. The MR study was supplemented by spectroscopic analysis. The lipid content was calculated and expressed as a percentage of lipid signal intensity relative to total signal intensity [fat fraction (FF)]. RESULTS: In the first MR study, the FF was 62.5±7%, in the second it was 70.75±5% and in the third it was 75±1%. We observed a statistically significant difference between FF values calculated at the various MR studies (p=0.02) and between red blood cell count (p=0.017), platelet count (p=0.003) and haematocrit (p<0.001) at the three MR studies. FF had a statistically significant correlation with the number of circulating platelets (p<0.01) CONCLUSIONS: MR spectroscopy of the bone marrow of NHL patients undergoing BMT is noninvasive and highly sensitive for characterising and monitoring bone marrow after BMT

Hematopoietic stem cell transplantation is effective curative treatment in pediatric refractory/aggressive Langerhans cell histiocytosis

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Immune genotypes, immune responses, and survival in a wild bird population

ACKNOWLEDGEMENTS We thank the Tsawout and Tseycum bands for allowing us to conduct research on Mandarte Island, and to the many contributors to long-term monitoring, especially L. Keller, P. Nietlisbach, and J. Krippel. We also thank C. Ritland, A. Miscampbell, and G. Huber for their assistance in the laboratory. All work was conducted under permit of the Canadian Wildlife Service and UBC Animal Care Committee. Funding Information: This study was generously supported by the Natural Sciences and Engineering Research Council of Canada via a Post‐doctoral Fellowship award to MJNF (PDF‐2014–454522) and a Discovery Grant to EAMS.Peer reviewedPublisher PD

Fitness Correlates Of Song Repertoire Size In Free-Living Song Sparrows (Melospiza Melodia)

Models of sexual selection propose that exaggerated secondary sexual ornaments indicate a male\u27s own fitness and the fitness of his offspring. These hypotheses have rarely been thoroughly tested in free-living individuals because overall fitness, as opposed to fitness components, is difficult to measure. We used 20 years of data from song sparrows ( Melospiza melodia) inhabiting Mandarte Island, British Columbia, Canada, to test whether a male\u27s song repertoire size, a secondary sexual trait, predicted overall measures of male or offspring fitness. Males with larger song repertoires contributed more independent and recruited offspring, and independent and recruited grandoffspring, to Mandarte\u27s population. This was because these males lived longer and reared a greater proportion of hatched chicks to independence from parental care, not because females mated to males with larger repertoires laid or hatched more eggs. Furthermore, independent offspring of males with larger repertoires were more likely to recruit and then to leave more grandoffspring than were offspring of males with small repertoires. Although we cannot distinguish whether observed fitness variation reflected genetic or environmental effects on males or their offspring, these data suggest that female song sparrows would gain immediate and intergenerational fitness benefits by pairing with males with large song repertoires