Behavioural adjustments of predators and prey to wind speed in the boreal forest.

Wind speed can have multifaceted effects on organisms including altering thermoregulation, locomotion, and sensory reception. While forest cover can substantially reduce wind speed at ground level, it is not known if animals living in forests show any behavioural responses to changes in wind speed. Here, we explored how three boreal forest mammals, a predator and two prey, altered their behaviour in response to average daily wind speeds during winter. We collected accelerometer data to determine wind speed effects on activity patterns and kill rates of free-ranging red squirrels (n = 144), snowshoe hares (n = 101), and Canada lynx (n = 27) in Kluane, Yukon from 2015 to 2018. All 3 species responded to increasing wind speeds by changing the time they were active, but effects were strongest in hares, which reduced daily activity by 25%, and lynx, which increased daily activity by 25%. Lynx also increased the number of feeding events by 40% on windy days. These results highlight that wind speed is an important abiotic variable that can affect behaviour, even in forested environments.

Optimisation of energetic and reproductive gains explains behavioural responses to environmental variation across seasons and years.

Animals switch between inactive and active states, simultaneously impacting their energy intake, energy expenditure and predation risk, and collectively defining how they engage with environmental variation and trophic interactions. We assess daily activity responses to long-term variation in temperature, resources and mating opportunities to examine whether individuals choose to be active or inactive according to an optimisation of the relative energetic and reproductive gains each state offers. We show that this simplified behavioural decision approach predicts most activity variation (R2  = 0.83) expressed by free-ranging red squirrels over 4 years, as quantified through accelerometer recordings (489 deployments; 5066 squirrel-days). Recognising activity as a determinant of energetic status, the predictability of activity variation aggregated at a daily scale, and the clear signal that behaviour is environmentally forced through optimisation of gain, provides an integrated approach to examine behavioural variation as an intermediary between environmental variation and energetic, life-history and ecological outcomes.

Post-weaning parental care increases fitness but is not heritable in North American red squirrels.

Most empirical attempts to explain the evolution of parental care have focused on its costs and benefits (i.e. fitness consequences). In contrast, few investigations have been made of the other necessary prerequisite for evolutionary change, inheritance. Here, we examine the fitness consequences and heritability (h(2)) of a post-weaning parental care behaviour (territory bequeathal) in a wild population of North American red squirrels. Each year, a subset (average across all years = 19%) of reproductive females bequeathed their territory to a dependent offspring. Bequeathing females experienced higher annual reproductive success and did not suffer a survival cost to themselves relative to those females retaining their territory. Bequeathing females thus realized higher relative annual fitness [ω = 1.18 ± 0.03 (SE)] than nonbequeathing females [ω = 0.96 ± 0.02 (SE)]. Additive genetic influences on bequeathal behaviour, however, were not significantly different from 0 (h(2) = 1.9 × 10(-3); 95% highest posterior density interval = 3.04 × 10(-8) to 0.37) and, in fact, bequeathal behaviour was not significantly repeatable (R = 2.0 × 10(-3); 95% HPD interval = 0-0.27). In contrast, directional environmental influences were apparent. Females were more likely to bequeath in years following low food abundance and when food availability in the upcoming autumn was high. Despite an evident fitness benefit, a lack of heritable genetic variance will constrain evolution of this trait.

The failing Fontan: what's NEXT...?

The Fontan procedure represents the final stage of the transition to single ventricle physiology. Conversion of very complex congenital heart anatomy, such as hypoplastic left heart syndrome, double-outlet right ventricle or double-inlet left ventricle, to a single ventricle has grown in popularity as morbidity and mortality have improved. As these patients grow, survivors are at risk for impaired ventricular dysfunction, plastic bronchitis, protein-losing enteropathy and late failure. Late failing Fontan patients represent a particularly vexing scenario for clinicians, as the only durable treatment option is cardiac transplantation. However, in the short-term, some of these patients require support beyond medical management, with mechanical circulatory support via extracorporeal life support or a ventricular assist device. We report the successful bridge of an adolescent female post-Fontan conversion with late severe cardiac failure. The patient was initially resuscitated with extracorporeal life support, transitioned to a single Berlin Heart EXCOR® ventricular assist device and, subsequently, underwent successful cardiac transplantation.

A quantitative genetic analysis of hibernation emergence date in a wild population of Columbian ground squirrels.

The life history schedules of wild organisms have long attracted scientific interest, and, in light of ongoing climate change, an understanding of their genetic and environmental underpinnings is increasingly becoming of applied concern. We used a multi-generation pedigree and detailed phenotypic records, spanning 18 years, to estimate the quantitative genetic influences on the timing of hibernation emergence in a wild population of Columbian ground squirrels (Urocitellus columbianus). Emergence date was significantly heritable [h(2) = 0.22 ± 0.05 (in females) and 0.34 ± 0.14 (in males)], and there was a positive genetic correlation (r(G) = 0.76 ± 0.22) between male and female emergence dates. In adult females, the heritabilities of body mass at emergence and oestrous date were h(2) = 0.23 ± 0.09 and h(2) = 0.18 ± 0.12, respectively. The date of hibernation emergence has been hypothesized to have evolved so as to synchronize subsequent reproduction with upcoming peaks in vegetation abundance. In support of this hypothesis, although levels of phenotypic variance in emergence date were higher than oestrous date, there was a highly significant genetic correlation between the two (r(G) = 0.98 ± 0.01). Hibernation is a prominent feature in the annual cycle of many small mammals, but our understanding of its influences lags behind that for phenological traits in many other taxa. Our results provide the first insight into its quantitative genetic influences and thus help contribute to a more general understanding of its evolutionary significance.

Idiopathic heterotopic ossification in the intensive care setting.

Heterotopic ossification is characterised by the periarticular deposition of ectopic bone. It typically occurs after trauma, neurogenic injury, or congenital causes. Idiopathic heterotopic ossification has been rarely reported. A patient who developed idiopathic heterotopic ossification in the intensive care unit without any known predisposing conditions is presented.

Hereditary neuropathy with liability to pressure palsies mimicking multifocal compression neuropathy.

Hereditary neuropathy with liability to pressure palsies (HNPP) is a recurrent disorder of the peripheral nervous system characterized by reversible episodes of sensorimotor deficits after neural compression injuries. Also known as tomaculous neuropathy, HNPP is further characterized ultrastructurally by multiple focal thickenings (tomacula) of peripheral myelin and has an autosomal dominant inheritance. The neuropathology of HNPP includes a partial deletion encoding the peripheral myelin protein 22 (PMP-22) gene on chromosome 17, resulting in underexpression of PMP-22. We describe multiple compression mononeuropathies in an individual with HNPP and report neuropathologic findings in 2 clinically asymptomatic family members. Diagnosis was confirmed using pulsed-field gel electrophoresis. We believe that this diagnosis is clinically underappreciated by hand surgeons and should be considered in the differential diagnosis of patients with atypical presentations of compression neuropathies.

Successful surgical treatment of spontaneous coronary artery dissection.

To present a case of spontaneous coronary artery dissection (SCAD). Spontaneous coronary artery dissection is rare and often difficult to surgically repair. Additionally, diagnosis by coronary angiography is uncommon. We present a case of SCAD in a postpartum woman who underwent successful surgical correction of the left anterior descending artery. Such surgical intervention in cases similar to ours is critical for survival.

Isolated septic arthritis caused by penicillin-resistant Streptococcus pneumoniae.

Streptococcus pneumoniae is a common cause of infection in the pediatric population, as well as an important cause of septic arthritis. The increased prevalence of drug-resistant S pneumoniae in North America has renewed interest in the use of pneumococcal vaccines. We describe the case of a child with isolated acute septic arthritis caused by infection with penicillin-resistant S pneumoniae.

Cellular angiofibroma of the vulva.

BACKGROUND: The cellular angiofibroma is a benign mesenchymal neoplasm that clinically and histologically must be distinguished from biologically more aggressive lesions. It typically arises in women of late reproductive age and lends itself to cure by complete local excision. A report of an unusual case in a postmenopausal patient is presented. CASE: A 77-year-old woman presented with a painless vulvar mass that slowly enlarged over 3 years. Past history included a hysterectomy and bilateral salpingo-oophorectomy followed by estrogen replacement therapy. Surgical excision of the mass was performed and there is no evidence of recurrence 1 year postoperatively. Histopathologic examination revealed an admixture of hyalinized blood vessels and loose cellular stroma characteristic of a cellular angiofibroma. Immunohistochemical studies revealed stromal cell immunoreactivity for vimentin and CD34 and nonreactivity for desmin, actin, and S100 protein. The nuclei of the stromal cells demonstrated strong reactivity for estrogen and progesterone receptors. CONCLUSION: Mesenchymal lesions of the vulva and perineum include both benign and malignant neoplasms. The cellular angiofibroma is benign; however, other lesions including the aggressive angiomyxoma must be excluded when arriving at that diagnosis. The role of long-term estrogen therapy in the genesis of this tumor awaits further analysis.

Successful treatment of an infant with Chromobacterium violaceum sepsis.

Chromobacterium violaceum sepsis, a rarely reported phenomenon, has a high mortality rate. We report a unique case of C. violaceum sepsis in an infant. A 4-month-old girl presented to our institution with fever, pustular skin lesions, and distended abdomen, as well as diminished activity and mental status. Radiological investigation revealed brain, lung, and hepatic abscesses. The infant was successfully treated with trimethoprim-sulfamethoxazole and ciprofloxacin.

Recurrent pericarditis after thoracic surgery.

Acute pericarditis is a frequent complication after cardiac and/or thoracic surgery. Recurrent acute pericarditis with multiple episodes is an uncommon phenomenon, however. Patients typically have chest pain and/or pericardial inflammation as shown by electrocardiography and echocardiography. Treatment presents a clinical challenge due to the condition's rarity and lack of multicenter comparative treatment studies. Numerous therapeutic modalities, including nonsteroidal anti-inflammatory agents (NSAIDs), corticosteroids, immunosuppressants, and pericardiectomy, have been used without overwhelming evidence of a standard protocol. We report a case in which 32 episodes of recurrent acute pericarditis occurred, emphasizing the need for multicenter trials comparing therapeutic modalities in the future.

An unusual case of malignant hyperthermia during desflurane anesthesia in an African-American patient.

IMPLICATIONS: Malignant hyperthermia is an uncommon, heritable condition triggered by anesthesia and is followed by an increase in temperature that may be fatal without prompt treatment. It is rare with desflurane and in black individuals of African descent. We present a case of malignant hyperthermia in an African-American patient during desflurane anesthesia.

Tuberculous enteritis: a case report.

Tuberculous enteritis is an unusual diagnosis in the United States. Because this entity is rare and the symptoms are not specific, the physician must have a high index of suspicion. We report the case of a young man with tuberculous involvement of the gastrointestinal tract who required surgical intervention for small bowel obstruction.

Angiogenesis and morphogenesis of murine fetal distal lung in an allograft model.

Neovascularization is crucial to lung morphogenesis; however, factors determining vessel growth and formation are poorly understood. The goal of our study was to develop an allograft model that would include maturation of the distal lung, thereby ultimately allowing us to study alveolar development, including microvascular formation. We transplanted 14-day gestational age embryonic mouse lung primordia subcutaneously into the back of nude mice for 3.5-14 days. Lung morphogenesis and neovascularization were evaluated by light microscopy, in situ hybridization, and immunohistochemical techniques. Embryonic 14-day gestational age control lungs had immature structural features consistent with pseudoglandular stage of lung development. In contrast, 14 days after subcutaneous transplantation of a 14-day gestational age lung, the allograft underwent significant structural morphogenesis and neovascularization. This was demonstrated by continued neovascularization and cellular differentiation, resulting in mature alveoli similar to those noted in the 2-day postnatal neonatal lung. Confirmation of maturation of the allograft was provided by progressive type II epithelial cell differentiation as evidenced by enhanced local expression of mRNA for surfactant protein C and a threefold (P < 0.008) increase in vessel formation as determined by immunocytochemical detection of platelet endothelial cell adhesion molecule-1 expression. Using the tyrosine kinase Flk-1 receptor (flk-1) LacZ transgene embryos, we determined that the neovascularization within the allograft was from the committed embryonic lung endothelium. Therefore, we have developed a defined murine allograft model that can be used to study distal lung development, including neovascularization. The model may be useful when used in conjunction with an altered genetic background (knockout or knock in) of the allograft and has the further decided advantage of bypassing placental barriers for introduction of pharmacological agents or DNA directly into the lung itself.

Nail-patella syndrome: an incidental finding from abdominal discomfort.

An otherwise healthy 18-year-old woman had abdominal discomfort. Physical examination and laboratory studies were unremarkable, with the exception of nail dystrophy of the ulnar digits. An abdominal plain film revealed bilateral posterior iliac horns, pathognomonic of nail-patella syndrome. Additional radiographs showed hypoplastic patellas bilaterally. While glomerulonephritis occurs in 30% of patients with nail-patella syndrome, there was no evidence of renal involvement.

Ultrastructural effects of the chelating agent 1,10-phenanthroline on Trypanosoma cruzi epimastigotes in vitro.

The in vitro effects of the metal chelator 1,10-phenanthroline (OPHEN) on the ultrastructure of Trypanosoma cruzi epimastigotes were investigated. Epimastigotes treated with OPHEN display swelling and electron-dense deposits in the kinetoplast, mitochondrion, and cisternae of the endoplasmic reticulum. These morphological alterations are dose-dependent and first appear at an OPHEN concentration of 5.0 microg/ml. Analytical electron microscope examination indicates that the metallic portion of the electron-dense deposits is predominantly calcium.