bluuebunny/crossref_metadata_2025 huggingface dataset:
Reconstruction of Congenital Sternal Cleft
Authors: Hinchcliff Katharine M. , Xue Yunfeng , Wong Granger B.
Published: January 2021

Introduction

Sternal cleft (SC) is a rare congenital deformity that results from failure of sternal bar fusion. Sternal cleft can be categorized as superior partial, inferior partial, or complete. Each form of SC can present as an isolated defect or in association with other congenital deformities, which presents a unique challenge for reconstructive surgeons. In our systematic review, we aim to summarize the published experience on repair of SCs and present a pragmatic approach to help guide reconstructive planning.

Methods

A systematic review was performed to identify all reported SC cases in literature that underwent sternal reconstruction.

Results

Seventy-one studies were identified from 1970 to 2019, which included a total of 115 patients. Superior partial SC was the most common SC variant, accounting for 65.2% (75/115) of all reported cases. There were 31 cases of complete SC (27.0%) and 9 cases (7.8%) of inferior partial SC; 49.6% of the patients (57/115) in our review had isolated SC without any other congenital deformities. Sixty-seven patients (60.3%) were treated with primary closure, with or without secondary maneuvers, such as chondrotomies, cartilage resection, or periosteal flaps. Alternative methods included interposition grafts, with autologous rib graft in 18 patients (15.8%), permanent mesh in 8 patients (7.0%), acellular dermal matrix in 5 patients (4.4%), sternal plate flap in 5 patients (4.4%), and nonthoracic autologous bone grafts in 4 patients (3.5%).

Conclusions

Our review supports that primary closure should be attempted regardless of patient age. For wider sternal gap, reconstruction with an autologous local graft or flap should be considered. When the patient does not have sufficient autologous tissue for a successful sternal reconstruction, alloplastic or allograft interposition options are a reasonable choice.
A 4-tier Protocolized Radiological Classification System for Leaks Following Sleeve Gastrectomy
Authors: Johari Yazmin , Catchlove William , Tse Madeleine , Shaw Kalai , Paul Eldho , Chen Richard , Loh Damien , Packiyanathan Andrew , Burton Paul , Nottle Peter , Ellis Samantha , Brown Wendy
Published: January 2021

Objectives:

To develop and validate a classification of sleeve gastrectomy leaks able to reliably predict outcomes, from protocolized computed tomography (CT) findings and readily available variables.

Summary of Background Data:

Leaks post sleeve gastrectomy remain morbid and resource-consuming. Incidence, treatments, and outcomes are variable, representing heterogeneity of the problem. A predictive tool available at presentation would aid management and predict outcomes.

Methods:

From a prospective database (2009–2018) we reviewed patients with staple line leaks. A Delphi process was undertaken on candidate variables (80–20). Correlations were performed to stratify 4 groupings based on outcomes (salvage resection, length of stay, and complications) and predictor variables. Training and validation cohorts were established by block randomization.

Results:

A 4-tiered classification was developed based on CT appearance and duration postsurgery. Interobserver agreement was high (κ = 0.85, P < 0.001). There were 59 patients, (training: 30, validation: 29). Age 42.5 ± 10.8 versus 38.9 ± 10.0 years (P = 0.187); female 65.5% versus 80.0% (P = 0.211), weight 127.4 ± 31.3 versus 141.0 ± 47.9 kg, (P = 0.203). In the training group, there was a trend toward longer hospital stays as grading increased (I = 10.5 d; II = 24 d; III = 66.5 d; IV = 72 d; P = 0.005). Risk of salvage resection increased (risk ratio grade 4 = 9; P = 0.043) as did complication severity (P = 0.027).

Findings were reproduced in the validation group: risk of salvage resection (P = 0.007), hospital stay (P = 0.001), complications (P = 0.016).

Conclusion:

We have developed and validated a classification system, based on protocolized CT imaging that predicts a step-wise increased risk of salvage resection, complication severity, and increased hospital stay. The system should aid patient management and facilitate comparisons of outcomes and efficacy of interventions.
Pancreatoduodenectomy at the Verona Pancreas Institute: the Evolution of Indications, Surgical Techniques, and Outcomes
Authors: Bassi Claudio , Marchegiani Giovanni , Giuliani Tommaso , Di Gioia Anthony , Andrianello Stefano , Zingaretti Caterina Costanza , Brentegani Giacomo , De Pastena Matteo , Fontana Martina , Pea Antonio , Paiella Salvatore , Malleo Giuseppe , Tuveri Massimiliano , Landoni Luca , Esposito Alessandro , Casetti Luca , Butturini Giovanni , Falconi Massimo , Salvia Roberto
Published: January 2021

Objective:

The aim of the present study was to critically reappraise the experience at our high-volume institution to obtain new insights for future directions.

Summary Background Data:

The indications, surgical techniques, and perioperative management of pancreatoduodenectomy (PD) have profoundly evolved over the last 20 years.

Methods:

All consecutive PDs performed during the last 20 years at the Verona Pancreas Institute were divided into four 5-year timeframes and retrospectively analyzed in terms of indications, intraoperative features, and surgical outcomes. Significant milestones were provided to understand practice changes using a before-after analysis method.

Results:

The study population consisted of 3000 patients. The median age, ASA ≥ 3 and number of nonbenchmark cases significantly increased over time (P < 0.005). Pancreatic cancer was the leading indication, representing 60% of patients/year in the last timeframe, 40% of whom received neoadjuvant treatment. Conversely, after the development of International Guidelines, the proportion of resected cystic neoplasms progressively and thoroughly decreased. Given the increased complexity of surgery for pancreatic cancer, the evolution of technologies, surgical techniques, and postoperative management allowed the maintenance of favorable surgical outcomes over time, with a stable 20.0% of patients with a Clavien-Dindo grade ≥ 3, an 11.7% failure to rescue and a 2.3% in-hospital mortality rate. The incidence of postoperative pancreatic fistula, hemorrhage, and delayed gastric emptying was 22.4%, 13.4%, and 12.4%, respectively.

Conclusions:

PD significantly evolved in Verona over the past 2 decades. Surgeries of greater complexity are currently performed on increasingly frailer patients, mostly for pancreatic cancer and often after neoadjuvant chemotherapy. However, the progression of all fields of pancreatic surgery, including the expanding use of postoperative pancreatic fistula mitigation strategies, has allowed satisfactory outcomes to be maintained.
Peer-reviewing in Surgical Journals: Revolutionize or Perish?
Authors: Chloros George D. , Giannoudis Vasileios P. , Giannoudis Peter V.
Published: January 2021

The gold standard of safe-guarding the quality of published science is peer review. However, this long-standing system has not evolved in today's digital world, where there has been an explosion in the number of publications and surgical journals. A journal's quality depends not only on the quality of papers submitted but is reflected upon the quality of its peer review process. Over the past decade journals are experiencing a rapidly escalating “peer review crisis” with editors struggling in recruiting reliable reviewers who will provide their skilled work for free with ever-diminishing incentives within today's restricted time-constraints. The problem is complex and difficult to solve, but more urgent than ever. Time is valuable and academicians, researchers and clinicians are overburdened and already extremely busy publishing their own research along with their ever growing clinical and administrative duties. Fewer and fewer individuals volunteer to provide their skilled work for free which is expected. The current incentives to review do not have a big impact on one's career and therefore are not realistic effective countermeasures.

As the limits of the system are constantly stretched, there will inevitably come a “point of no return” and Surgical Journals will be the ones to first take the hit as there is an overwhelming evidence of burnout in the surgical specialties and the Surgical community is almost 50% smaller than its Medical counterpart.

This review identifies the potential causes of the peer-review crisis, outlines the incentives and drawbacks of being a reviewer, summarizes the currently established common practices of rewarding reviewers and the existing and potential solutions to the problem. The magnitude of the problem and unsustainability that will make it perish are discussed along with its current flaws. Finally, recommendations are made to address many of the weaknesses of the system with the hope to revive it.
Multisystem outcomes and predictors of mortality in critically ill patients with COVID-19: Demographics and disease acuity matter more than comorbidities or treatment modalities
Authors: Alser Osaid , Mokhtari Ava , Naar Leon , Langeveld Kimberly , Breen Kerry A. , El Moheb Mohamad , Kapoen Carolijn , Gaitanidis Apostolos , Christensen Mathias A. , Maurer Lydia R. , Mashbari Hassan , Bankhead-Kendall Brittany , Parks Jonathan , Fawley Jason , Saillant Noelle , Mendoza April , Paranjape Charudutt , Fagenholz Peter , King David , Lee Jarone , Farhat Maha R. , Velmahos George C. , Kaafarani Haytham M.A.
Published: January 2021

BACKGROUND

We sought to describe characteristics, multisystem outcomes, and predictors of mortality of the critically ill COVID-19 patients in the largest hospital in Massachusetts.

METHODS

This is a prospective cohort study. All patients admitted to the intensive care unit (ICU) with reverse-transcriptase–polymerase chain reaction–confirmed severe acute respiratory syndrome coronavirus 2 infection between March 14, 2020, and April 28, 2020, were included; hospital and multisystem outcomes were evaluated. Data were collected from electronic records. Acute respiratory distress syndrome (ARDS) was defined as PaO2/FiO2 ratio of ≤300 during admission and bilateral radiographic pulmonary opacities. Multivariable logistic regression analyses adjusting for available confounders were performed to identify predictors of mortality.

RESULTS

A total of 235 patients were included. The median (interquartile range [IQR]) Sequential Organ Failure Assessment score was 5 (3–8), and the median (IQR) PaO2/FiO2 was 208 (146–300) with 86.4% of patients meeting criteria for ARDS. The median (IQR) follow-up was 92 (86–99) days, and the median ICU length of stay was 16 (8–25) days; 62.1% of patients were proned, 49.8% required neuromuscular blockade, and 3.4% required extracorporeal membrane oxygenation. The most common complications were shock (88.9%), acute kidney injury (AKI) (69.8%), secondary bacterial pneumonia (70.6%), and pressure ulcers (51.1%). As of July 8, 2020, 175 patients (74.5%) were discharged alive (61.7% to skilled nursing or rehabilitation facility), 58 (24.7%) died in the hospital, and only 2 patients were still hospitalized, but out of the ICU. Age (odds ratio [OR], 1.08; 95% confidence interval [CI], 1.04–1.12), higher median Sequential Organ Failure Assessment score at ICU admission (OR, 1.24; 95% CI, 1.06–1.43), elevated creatine kinase of ≥1,000 U/L at hospital admission (OR, 6.64; 95% CI, 1.51–29.17), and severe ARDS (OR, 5.24; 95% CI, 1.18–23.29) independently predicted hospital mortality.

Comorbidities, steroids, and hydroxychloroquine treatment did not predict mortality.

CONCLUSION

We present here the outcomes of critically ill patients with COVID-19. Age, acuity of disease, and severe ARDS predicted mortality rather than comorbidities.

LEVEL OF EVIDENCE

Prognostic, level III.
Lower Extremity Muscle Power Following Total Knee Arthroplasty
Authors: Shultz Stephen Tyler , MacLennan Brett
Published: January 2021

Total knee arthroplasty (TKA) is a common treatment for osteoarthritis of the knee joint. A decrease in lower extremity power is commonly seen in older adults who have knee osteoarthritis and TKA. This review integrates the current evidence regarding the change in lower extremity muscle power following TKA, rehabilitation efforts to improve power following TKA, and changes in muscle power related to function after TKA. It is recommended that lower extremity muscle power be measured and rehabilitated appropriately following TKA. A need for future research examining best treatment protocols to develop lower extremity power after TKA is warranted.
The Prevalence and Associated Factors of the Fear of Falling in Elderly Patients at the Primary Care Clinic of Songklanagarind Hospital
Authors: Chamroonkiadtikun Panya , Ananchaisarp Thareerat , Wajancomkul Panitan
Published: January 2021

Objective:

The fear of falling (FOF) is defined as low perceived self-efficacy at avoiding falls during the nonhazardous activities of daily life. The FOF can lead to negative consequences including the physical change, and it might decrease the quality of life of the elderly. The aim of study was to assess the prevalence of FOF and identify the associated factors among Thai elderly patients.

Methods:

A cross-sectional study was performed. A total of 101 participants 60 years or older were recruited from October to November 2017. The data obtained through questionnaires, face-to-face interviews, and gait and balance tests that were measured by the researchers. The structured questionnaire included demographic data, history of falls, the Thai geriatric depression scale (TGDS), the Falls Efficacy Scale-International (FES-I), and the Thai mental state examination (TMSE). The balance and gait tests were conducted using the timed up and go (TUG) test and the Berg balance scale.

Results:

The prevalence of FOF was 70.3%. The logistic regression analysis showed a significant association between FOF and female gender (odds ratio [OR], 4.07; 95% confidence interval [CI], 1.63-10.46), whereas factors were not associated with FOF included age, living status, education, number of underlying disease, comorbidities, number of drugs used, history of fall, consequences of falls, visual acuity, TGDS, TMSE, TUG, and Berg balance test. In the multivariate model, the factors associated with the FOF were gender (OR, 4.28; 95% CI, 1.58-12.14) and hypertension (OR, 3.46; 95% CI, 1.11-11.72).

Conclusion:

The prevalence of FOF was high among Thai elderly patients. The present findings may help health care providers identify individuals who have FOF. These people could benefit from interventions, which focus on gender differences and hypertension aimed at reducing the FOF.
Current advances in plasma and cerebrospinal fluid biomarkers in Alzheimer's disease
Authors: Leuzy Antoine , Cullen Nicholas C. , Mattsson-Carlgren Niklas , Hansson Oskar
Published: January 2021

Purpose of review

This review provides a concise overview of recent advances in cerebrospinal fluid (CSF) and blood-based biomarkers of Alzheimer's disease lesions.

Recent findings

Important recent advances for CSF Alzheimer's disease biomarkers include the introduction of fully automated assays, the development and implementation of certified reference materials for CSF Aβ42 and a unified protocol for handling of samples, which all support reliability and availability of CSF Alzheimer's disease biomarkers. Aβ deposition can be detected using Aβ42/Aβ40 ratio in both CSF and plasma, though a much more modest change is seen in plasma. Tau aggregation can be detected using phosphorylated tau (P-tau) at threonine 181 and 217 in CSF, with similar accuracy in plasma. Neurofilament light (NfL) be measured in CSF and shows similar diagnostic accuracy in plasma. Though total tau (T-tau) can also be measured in plasma, this measure is of limited clinical relevance for Alzheimer's disease in its current immunoassay format.

Alzheimer's disease biomarkers, including Aβ, P-tau and NfL can now be reliably measured in both CSF and blood. Plasma-based measures of P-tau show particular promise, with potential applications in both clinical practice and in clinical trials.
Visual field defects in temporal lobe epilepsy surgery
Authors: Vakharia Vejay N. , Diehl Beate , Tisdall Martin
Published: January 2021

Purpose of review

Surgery can provide a robust long-standing seizure remission in drug-refractory mesial temporal lobe epilepsy (MTLE). Despite this, a significant proportion of postoperative patients are ineligible to gain a driving licence due to the size of the subsequent visual field defect (VFD). The amygdala and hippocampus are intimately related to several important white fibre association tracts and damage to the optic radiation results in a contralateral superior quadrantanopia. For this reason, several different modifications to established surgical approaches and novel techniques have recently been applied to mitigate or prevent damage to the optic radiation. There is still no consensus on which operative technique results in optimal outcomes regarding seizure remission, neuropsychological sequelae and VFD rates. We explore contemporary surgical approaches to the mesial temporal lobe and describe the intraoperative use of tractography and iMRI in preventing VFDs.

Recent findings

Established approaches for the surgical treatment of MTLE include standardized approaches in the form of anterior temporal lobectomies, selective approaches and various modifications thereof. Recent advancements in microsurgical techniques have seen numerous modifications to these approaches to spare the optic radiation as well as the introduction of minimally invasive alternatives such as laser interstitial thermal therapy (LITT) and stereotactic radiosurgery (SRS). The intraoperative use of optic radiation tractography through overlays in the operative microscope and interventional MRI suites to correct for brain shift have been shown to reduce VFDs.

VFDs following the surgical treatment of drug-refractory MTLE can have a significant impact on the quality of life. Each of the surgical techniques carries a risk to the visual pathways but the use of minimally invasive techniques as well as surgical adjuncts may reduce or prevent acquired VFDs.
Interictal autonomic dysfunction
Authors: Sivathamboo Shobi , Perucca Piero
Published: January 2021

Purpose of review

Epilepsy is associated with autonomic dysfunction. Here, we provide an up-to-date review on measures of interictal autonomic function, focusing on heart rate variability (HRV), baroreflex sensitivity (BRS) and electrodermal activity (EDA).

Recent findings

Resting HRV, BRS and EDA are altered in patients with epilepsy compared with healthy controls. A larger body of work is available for HRV compared with BRS and EDA, and points to interictal HRV derangements across a wide range of epilepsies, including focal, generalized, and combined generalized and focal epilepsies. HRV alterations are most pronounced in temporal lobe epilepsy, Dravet syndrome and drug-resistant and chronic epilepsies. There are conflicting data on the effect of antiseizure medications on measures of interictal autonomic function. However, carbamazepine has been associated with decreased HRV. Epilepsy surgery and vagus nerve stimulation do not appear to have substantial impact on measures of interictal autonomic function but well designed studies are lacking.

Patients with epilepsy, particularly those with longstanding uncontrolled seizures, have measurable alterations of resting autonomic function. These alterations may be relevant to the increased risk of premature mortality in epilepsy, including sudden unexpected death in epilepsy, which warrants investigation in future research.
Prostaglandin 15d-PGJ2 targets PPARγ and opioid receptors to prevent muscle hyperalgesia in rats
Authors: Santos Diogo F. S. , Melo-Aquino Bruna , Jorge Carolina O. , Clemente-Napimoga Juliana T. , Taylor Bradley K. , Oliveira-Fusaro Maria C.G.
Published: January 2021

Pharmacological agents directed to either opioid receptors or peroxisome proliferator-activated receptor gamma (PPARγ) at peripheral tissues reduce behavioral signs of persistent pain. Both receptors are expressed in muscle tissue, but the contribution of PPARγ activation to muscle pain and its modulation by opioid receptors remains unknown. To address this question, we first tested whether the endogenous PPARγ ligand 15d-PGJ2 would decrease mechanical hyperalgesia induced by carrageenan administration into the gastrocnemius muscle of rats. Next, we used receptor antagonists to determine whether the antihyperalgesic effect of 15-deoxyΔ-12,14-prostaglandin J2 (15d-PGJ2) was PPARγ- or opioid receptor-dependent. Three hours after carrageenan, muscle hyperalgesia was quantified with the Randall–Selitto test. 15d-PGJ2 prevented carrageenan-induced muscle hyperalgesia in a dose-dependent manner. The antihyperalgesic effect of 15d-PGJ2 was dose-dependently inhibited by either the PPARγ antagonist, 2-chloro-5-nitro-N-phenylbenzamide, or by the opioid receptor antagonist, naloxone. We conclude that 15d-PGJ2 targets PPARγ and opioid receptors to prevent muscle hyperalgesia. We suggest that local PPARγ receptors are important pharmacological targets for inflammatory muscle pain.
Memantine protects blood–brain barrier integrity and attenuates neurological deficits through inhibiting nitric oxide synthase ser1412 phosphorylation in intracerebral hemorrhage rats: involvement of peroxynitrite-related matrix metalloproteinase-9/NLRP3 inflammasome activation
Authors: Chen Xiaowei , Xiang Xu , Xie Teng , Chen Zhijun , Mou Yu , Gao Zixu , Xie Xun , Song Min , Huang Hui , Gao Ziyun , Chen Min
Published: January 2021

Memantine has demonstrated beneficial effects on several types of brain insults via therapeutic mechanisms mainly related to its activity as a receptor antagonist of N-methyl-d-aspartate. However, the influences of memantine on intracerebral hemorrhage (ICH) remain obscure. This research probed into the neurovascular protective mechanisms of memantine after ICH and its impacts on neuronal nitric oxide synthase (nNOS) ser1412 phosphorylation. ICH model was established by employing intrastriatal collagenase injection in rats. After modeling, rats were then allocated randomly into sham-operated (sham), vehicle-treated (ICH+V), and memantine-administrated (ICH+M) groups. Memantine (20 mg/kg/day) was intraperitoneally administered 30 min after ICH and thenceforth once daily. Rats were dedicated at 0.25, 6, 12, 24 h, 3 and 7 d post-ICH for measurement of corresponding indexes. Behavioral changes, brain edema, levels of nNOS ser1412 phosphorylation, peroxynitrite, matrix metalloproteinase (MMP)-9, NLRP3, IL-1β and numbers of dying neurons, as well as the cellular localization of gelatinolytic activity, were detected among the groups. Memantine improved the neurologic deficits and mitigated brain water content, levels of MMP-9, NLRP3, IL-1β and dying neurons. Additionally, treatment with memantine also reduced nNOS ser1412 phosphorylation and peroxynitrite formation compared with the ICH+V group at 24 h after ICH. In situ zymography simultaneously revealed that gelatinase activity was primarily colocalized with vessel walls and neurons. We concluded that memantine ameliorated blood–brain barrier disruption and neurologic dysfunction in an ICH rat model. The underlying mechanism might involve repression of nNOS ser1412 phosphorylation, as well as peroxynitrite-related MMP-9 and NLRP3 inflammasome activation.
Glutamine’s protection against brain damage in septic rats via increased protein oxygen-N-acetylglucosamine modification
Authors: Wang Jin , Lu Xinjian , Zheng Kang , Jing Liang
Published: January 2021

Objective

This study aimed to observe the effect of glutamine (Gln) on brain damage in septic rats and explore its possible mechanism.

Methods

Ninety-three Sprague–Dawley rats were randomly divided into five groups: sham operation group, sepsis group, Gln-treated group, quercetin/Gln-treated group, and alloxan/Gln-treated group. The rats in each group were continuously monitored for mean arterial pressure (MAP) and heart rate changes for 16 h. Neuroreflex scores were measured 24 h after surgery. The water content of the brain tissue was measured. Plasma neuron enolase and cysteine protease-3 were measured using the ELISA. The expression levels of heat shock protein 70 (HSP70) and oxygen-N-acetylglucosamine (O-GlcNAc) were determined by western blot analysis. Finally, the brain tissue was observed via hematoxylin and eosin staining.

Results

The brain tissue water content, plasma neuron enolase content, brain tissue cysteine protease-3 content, and nerve reflex score were significantly lower in the Gln-treated group than in the sepsis group (P < 0.05). At the same time, the pathological brain tissue damage in the Gln-treated group was also significantly reduced. It is worth noting that the expression of HSP70 and the protein O-GlcNAc modification levels in the Gln-treated group were significantly elevated than the levels in the sepsis group (P < 0.05), and reversed by pretreatment with the HSP and O-GlcNAc inhibitors quercetion and alloxan.

Conclusions

Gln can attenuate brain damage in rats with sepsis, which may be associated with increased protein O-GlcNAc modification.
Effects of site, cerebral perfusion and degree of cerebral artery stenosis on cognitive function
Authors: Xie Binbin , Liu Yidan , Wu DongMei , Li Gongbo , Chen Taosong , Xiao Shufang , Yang Jing , Li Jiamin , Li Xiaofeng
Published: January 2021

Objective

To investigate the effects of site, cerebral perfusion and degree of cerebral artery stenosis (CAS) on cognitive function.

Methods

A total of 57 patients with CAS and 53 controls from January 2019 to December 2019 were included. The former group was further divided into different subgroups according to the site, cerebral perfusion and degree of CAS. A series of neuropsychological tests were performed to evaluate the cognitive domains (such as memory, executive function, psychomotor speed, etc.). Rank sum test, t test, Chi-square test and analysis of variance were used for data analysis. Spearman correlation analysis was used to examine the relationship between the site, cerebral perfusion and degree of CAS and all tests’ scores.

Results

For patients with CAS who have decreased cerebral perfusion, their global cognitive function, memory, psychomotor speed, executive function and frontal lobe function were significantly impaired (all P < 0.05). There was a significant decrease in global cognitive function, psychomotor speed, memory, executive function and frontal lobe function in patients with anterior circulation stenosis (all P < 0.05). Moderate and severe CAS impaired subjects’ global cognitive function, memory, psychomotor speed, executive function and frontal lobe function (all P < 0.05). There was a correlation between the site, cerebral perfusion, the degree of CAS and cognitive function.

Conclusion

Global cognitive function, memory, psychomotor speed, frontal lobe function and executive function are impaired in patients with CAS, especially in those with anterior circulatory stenosis, moderate to severe stenosis and low cerebral perfusion.

See Video Abstract, http://links.lww.com/WNR/A613.
Mild hypothermia protects rat cortical neurons against oxygen-glucose deprivation/reoxygenation injury via the PI3K/Akt pathway
Authors: Gao Zan , Zhang Zhiqiang , Bian Qinghu , Li Yanli , Ma Dongyang , Liu Zheng , Zhang Shan
Published: January 2021

Ischemic stroke is the most frequent cause of long-term morbidity and mortality in the elderly worldwide. Mild hypothermia (32–35°C) has been found to have a neuroprotective effect against ischemic stroke. However, the protective mechanisms remain unclear. In the present study, we explore the neuroprotective effect of mild hypothermia in neuron-astrocyte cocultures by oxygen-glucose deprivation/reoxygenation (OGD/R) as well as the underlying mechanisms. Thionin staining was performed and cell viability, extracellular glutamate concentration and the phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt) pathway-related proteins were detected after OGD/R. The results indicated that mild hypothermia significantly alleviated damage to Nissl bodies and increased the viability of neurons, which alleviated OGD/R-triggered neuronal injury. Furthermore, mild hypothermia significantly enhanced the phosphorylation of Akt (pAkt) and glutamate transporter-1 (GLT-1) and reduced extracellular glutamate concentration after OGD/R. When the PI3K inhibitor LY294002 was added, neuronal viability and the expression of pAkt and GLT-1 decreased, and extracellular glutamate concentration increased. The protective effect of mild hypothermia was counteracted by LY294002. There was no significant change in neuronal viability or the expression of pAkt and GLT-1 in the group treated with dihydrokainate, an inhibitor of GLT-1-function, compared with the mild hypothermia + OGD/R (HOGD) group, but extracellular glutamate concentration was increased. Consequently, mild hypothermia promoted glutamate clearance by regulating GLT-1 expression via the PI3K/Akt pathway, providing a neuroprotective effect against OGD/R injury.
Social structure defines spatial transmission of African swine fever in wild boar
Authors: Pepin Kim M. , Golnar Andrew , Podgórski Tomasz
Published: January 2021

The spatial spread of infectious disease is determined by spatial and social processes such as animal space use and family group structure. Yet, the impacts of social processes on spatial spread remain poorly understood and estimates of spatial transmission kernels (STKs) often exclude social structure. Understanding the impacts of social structure on STKs is important for obtaining robust inferences for policy decisions and optimizing response plans. We fit spatially explicit transmission models with different assumptions about contact structure to African swine fever virus surveillance data from eastern Poland from 2014 to 2015 and evaluated how social structure affected inference of STKs and spatial spread. The model with social structure provided better inference of spatial spread, predicted that approximately 80% of transmission events occurred within family groups, and that transmission was weakly female-biased (other models predicted weakly male-biased transmission). In all models, most transmission events were within 1.5 km, with some rare events at longer distances. Effective reproductive numbers were between 1.1 and 2.5 (maximum values between 4 and 8). Social structure can modify spatial transmission dynamics. Accounting for this additional contact heterogeneity in spatial transmission models could provide more robust inferences of STKs for policy decisions, identify best control targets and improve transparency in model uncertainty.
Butterflies fly using efficient propulsive clap mechanism owing to flexible wings
Authors: Johansson L. C. , Henningsson P.
Published: January 2021

Butterflies look like no other flying animal, with unusually short, broad and large wings relative to their body size. Previous studies have suggested butterflies use several unsteady aerodynamic mechanisms to boost force production with upstroke wing clap being a prominent feature. When the wings clap together at the end of upstroke the air between the wings is pressed out, creating a jet, pushing the animal in the opposite direction. Although viewed, for the last 50 years, as a crucial mechanism in insect flight, quantitative aerodynamic measurements of the clap in freely flying animals are lacking. Using quantitative flow measurements behind freely flying butterflies during take-off and a mechanical clapper, we provide aerodynamic performance estimates for the wing clap. We show that flexible butterfly wings, forming a cupped shape during the upstroke and clap, thrust the butterfly forwards, while the downstroke is used for weight support. We further show that flexible wings dramatically increase the useful impulse (+22%) and efficiency (+28%) of the clap compared to rigid wings. Combined, our results suggest butterflies evolved a highly effective clap, which provides a mechanistic hypothesis for their unique wing morphology. Furthermore, our findings could aid the design of man-made flapping drones, boosting propulsive performance.
Viral pathogenesis of SARS-CoV-2 infection and male reproductive health
Authors: Roychoudhury Shubhadeep , Das Anandan , Jha Niraj Kumar , Kesari Kavindra Kumar , Roychoudhury Shatabhisha , Jha Saurabh Kumar , Kosgi Raghavender , Choudhury Arun Paul , Lukac Norbert , Madhu Nithar Ranjan , Kumar Dhruv , Slama Petr
Published: January 2021

Coronavirus disease 2019 (COVID-19) has emerged as a new public health crisis, threatening almost all aspects of human life. Originating in bats, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted to humans through unknown intermediate hosts, where it is primarily known to cause pneumonia-like complications in the respiratory system. Organ-to-organ transmission has not been ruled out, thereby raising the possibility of the impact of SARS-CoV-2 infection on multiple organ systems. The male reproductive system has been hypothesized to be a potential target of SARS-CoV-2 infection, which is supported by some preliminary evidence. This may pose a global threat to male fertility potential, as men are more prone to SARS-CoV-2 infection than women, especially those of reproductive age. Preliminary reports have also indicated the possibility of sexual transmission of SARS-CoV-2. It may cause severe complications in infected couples. This review focuses on the pathophysiology of potential SARS-CoV-2 infection in the reproductive organs of males along with their invasion mechanisms. The risks of COVID-19 on male fertility as well as the differences in vulnerability to SARS-CoV-2 infection compared with females have also been highlighted.
Perceptual correlates of homosynaptic long-term potentiation in human nociceptive pathways: a replication study
Authors: van den Broeke E. N. , Vanmaele T. , Mouraux A. , Stouffs A. , Biurrun-Manresa J. , Torta D. M.
Published: January 2021

Animal studies have shown that high-frequency stimulation (HFS) of peripheral C-fibres induces long-term potentiation (LTP) within spinal nociceptive pathways. The aim of this replication study was to assess if a perceptual correlate of LTP can be observed in humans. In 20 healthy volunteers, we applied HFS to the left or right volar forearm. Before and after applying HFS, we delivered single electrical test stimuli through the HFS electrode while a second electrode at the contra-lateral arm served as a control condition. Moreover, to test the efficacy of the HFS protocol, we quantified changes in mechanical pinprick sensitivity before and after HFS of the skin surrounding both electrodes. The perceived intensity was collected for both electrical and mechanical stimuli. After HFS, the perceived pain intensity elicited by the mechanical pinprick stimuli applied on the skin surrounding the HFS-treated site was significantly higher compared to control site (heterotopic effect). Furthermore, we found a higher perceived pain intensity for single electrical stimuli delivered to the HFS-treated site compared to the control site (homotopic effect). Whether the homotopic effect reflects a perceptual correlate of homosynaptic LTP remains to be elucidated.
The effects of ground-irregularity-cancelling prosthesis control on balance over uneven surfaces
Authors: Chiu Vincent L. , Voloshina Alexandra S. , Collins Steven H.
Published: January 2021

Over half of individuals with a lower-limb amputation are unable to walk on uneven terrain. Using a prosthesis emulator system, we developed an irregularity-cancelling controller intended to reduce the effect of disturbances resulting from uneven surfaces. This controller functions by changing the neutral angles of two forefoot digits in response to local terrain heights. To isolate the effects of the controller, we also programmed a spring-like controller that maintained fixed neutral angles. Five participants with transtibial amputation walked on a treadmill with an uneven walking surface. Compared with the spring-like controller, the irregularity-cancelling controller reduced ankle torque variability by 41% in the sagittal plane and 64% in the frontal plane. However, user outcomes associated with balance were mostly unaffected; only trunk movement variability was reduced, whereas metabolic rate, mediolateral centre of mass motion, and variabilities in step width, step length and step time were unchanged. We conclude that reducing ankle torque variability of the affected limb is not sufficient for reducing the overall effect of disturbances due to uneven terrain. It is possible that other factors, such as changes in step height or disturbances to the intact limb, play a larger role in difficulty balancing while walking over uneven surfaces.
Wireless power distributions in multi-cavity systems at high frequencies
Authors: Adnan Farasatul , Blakaj Valon , Phang Sendy , Antonsen Thomas M. , Creagh Stephen C. , Gradoni Gabriele , Tanner Gregor
Published: January 2021

The next generations of wireless networks will work in frequency bands ranging from sub-6 GHz up to 100 GHz. Radio signal propagation differs here in several critical aspects from the behaviour in the microwave frequencies currently used. With wavelengths in the millimetre range (mmWave), both penetration loss and free-space path loss increase, while specular reflection will dominate over diffraction as an important propagation channel. Thus, current channel model protocols used for the generation of mobile networks and based on statistical parameter distributions obtained from measurements become insufficient due to the lack of deterministic information about the surroundings of the base station and the receiver-devices. These challenges call for new modelling tools for channel modelling which work in the short-wavelength/high-frequency limit and incorporate site-specific details—both indoors and outdoors. Typical high-frequency tools used in this context—besides purely statistical approaches—are based on ray-tracing techniques. Ray-tracing can become challenging when multiple reflections dominate. In this context, mesh-based energy flow methods have become popular in recent years. In this study, we compare the two approaches both in terms of accuracy and efficiency and benchmark them against traditional power balance methods.
Elastic multi-blisters induced by geometric constraints
Authors: De Tommasi D. , Devillanova G. , Maddalena F. , Napoli G. , Puglisi G.
Published: January 2021

We study a prototypical system describing instability effects due to geometric constraints in the framework of nonlinear elasticity. By considering the equilibrium configurations of an elastic ring constrained inside a rigid circle with smaller radius, we analytically determine different possible shapes, reproducing well-known physical phenomena. As we show, both single- (with different complexity) and multi-blister configurations can be observed, but the lowest energy always corresponds to single-blister solutions. Important physical insight is attained through an analogy between the elastica and the dynamics of a nonlinear pendulum. A complete geometric characterization is attained, proving symmetry and other relevant properties. The effectiveness of the model is tested against a simple experiment by considering a thin polymer strip constrained in a rigid cylinder.
Breakdown of similarity solutions: a perturbation approach for front propagation during foam-improved oil recovery
Authors: Torres-Ulloa Carlos , Grassia Paul
Published: January 2021

The pressure-driven growth model has been employed to study a propagating foam front in the foam-improved oil recovery process. A first-order solution of the model proves the existence of a concave corner on the front, which initially migrates downwards at a well defined speed that differs from the speed of front material points. At later times, however, it remains unclear how the concave corner moves and interacts with points on the front either side of it, specifically whether material points are extracted from the corner or consumed by it. To address these questions, a second-order solution is proposed, perturbing the aforementioned first-order solution. However, the perturbation is challenging to develop, owing to the nature of the first-order solution, which is a similarity solution that exhibits strong spatio-temporal non-uniformities. The second-order solution indicates that the corner’s vertical velocity component decreases as the front migrates and that points initially extracted from the front are subsequently consumed by it. Overall, the perturbation approach developed herein demonstrates how early-time similarity solutions exhibiting strong spatio-temporal non-uniformities break down as time proceeds.
Self-clearance of
Mycobacterium tuberculosis
infection: implications for lifetime risk and population at-risk of tuberculosis disease
Authors: Emery Jon C. , Richards Alexandra S. , Dale Katie D. , McQuaid C. Finn , White Richard G. , Denholm Justin T. , Houben Rein M. G. J.
Published: January 2021

Background
: it is widely assumed that individuals with
Mycobacterium tuberculosis
(
Mtb
) infection remain at lifelong risk of tuberculosis (TB) disease. However, there is substantial evidence that self-clearance of
Mtb
infection can occur. We infer a curve of self-clearance by time since infection and explore its implications for TB epidemiology.
Methods and findings
: data for self-clearance were inferred using post-mortem and tuberculin-skin-test reversion studies. A cohort model allowing for self-clearance was fitted in a Bayesian framework before estimating the lifetime risk of TB disease and the population infected with
Mtb
in India, China and Japan in 2019. We estimated that 24.4% (17.8–32.6%, 95% uncertainty interval (UI)) of individuals self-clear within 10 years of infection, and 73.1% (64.6–81.7%) over a lifetime. The lifetime risk of TB disease was 17.0% (10.9–22.5%), compared to 12.6% (10.1–15.0%) assuming lifelong infection. The population at risk of TB disease in India, China and Japan was 35–80% (95% UI) smaller in the self-clearance scenario.
Conclusions
: the population with a viable
Mtb
infection may be markedly smaller than generally assumed, with such individuals at greater risk of TB disease. The ability to identify these individuals could dramatically improve the targeting of preventive programmes and inform TB vaccine development, bringing TB elimination within reach of feasibility.
Extensive hybridization reveals multiple coloration genes underlying a complex plumage phenotype
Authors: Aguillon Stepfanie M. , Walsh Jennifer , Lovette Irby J.
Published: January 2021

Coloration is an important target of both natural and sexual selection. Discovering the genetic basis of colour differences can help us to understand how this visually striking phenotype evolves. Hybridizing taxa with both clear colour differences and shallow genomic divergences are unusually tractable for associating coloration phenotypes with their causal genotypes. Here, we leverage the extensive admixture between two common North American woodpeckers—yellow-shafted and red-shafted flickers—to identify the genomic bases of six distinct plumage patches involving both melanin and carotenoid pigments. Comparisons between flickers across approximately 7.25 million genome-wide SNPs show that these two forms differ at only a small proportion of the genome (meanFST= 0.008). Within the few highly differentiated genomic regions, we identify 368 SNPs significantly associated with four of the six plumage patches. These SNPs are linked to multiple genes known to be involved in melanin and carotenoid pigmentation. For example, a gene (CYP2J19) known to cause yellow to red colour transitions in other birds is strongly associated with the yellow versus red differences in the wing and tail feathers of these flickers. Additionally, our analyses suggest novel links between known melanin genes and carotenoid coloration. Our finding of patch-specific control of plumage coloration adds to the growing body of literature suggesting colour diversity in animals could be created through selection acting on novel combinations of coloration genes.
Silence of the killers: discovery of male-killing suppression in a rearing strain of the small brown planthopper,
Laodelphax striatellus
Authors: Yoshida Kazuki , Sanada-Morimura Sachiyo , Huang Shou-Horng , Tokuda Makoto
Published: January 2021

According to evolutionary theory, sex ratio distortions caused by reproductive parasites such as
Wolbachia
and
Spiroplasma
are predicted to be rapidly normalized by the emergence of host nuclear suppressors. However, such processes in the evolutionary arms race are difficult to observe because sex ratio biases will be promptly hidden and become superficially unrecognizable. The evolution of genetic suppressors has been reported in just two insect species so far. In the small brown planthopper,
Laodelphax striatellus
, female-biases caused by
Spiroplasma
, which is a ‘late’ male-killer, have been found in some populations. During the continuous rearing of
L. striatellus
, we noted that a rearing strain had a 1 : 1 sex ratio even though it harboured
Spiroplasma
. Through introgression crossing experiments with a strain lacking suppressors, we revealed that the
L. striatellus
strain had the zygotic male-killing suppressor acting as a dominant trait. The male-killing phenotype was hidden by the suppressor even though
Spiroplasma
retained its male-killing ability. This is the first study to demonstrate the existence of a late male-killing suppressor and its mode of inheritance. Our results, together with those of previous studies, suggest that the inheritance modes of male-killing suppressors are similar regardless of insect order or early or late male killing.
Poorly differentiated XX/XY sex chromosomes are widely shared across skink radiation
Authors: Kostmann Alexander , Kratochvíl Lukáš , Rovatsos Michail
Published: January 2021

Differentiated sex chromosomes are believed to be evolutionarily stable, while poorly differentiated sex chromosomes are considered to be prone to turnovers. With around 1700 currently known species formingca15% of reptile species diversity, skinks (family Scincidae) are a very diverse group of squamates known for their large ecological and morphological variability. Skinks generally have poorly differentiated and cytogenetically indistinguishable sex chromosomes, and their sex determination was suggested to be highly variable. Here, we determined X-linked genes in the common sandfish (Scincus scincus) and demonstrate that skinks have shared the same homologous XX/XY sex chromosomes across their wide phylogenetic spectrum for at least 85 million years, approaching the age of the highly differentiated ZZ/ZW sex chromosomes of birds and advanced snakes. Skinks thus demonstrate that even poorly differentiated sex chromosomes can be evolutionarily stable. The conservation of sex chromosomes across skinks allows us to introduce the first molecular sexing method widely applicable in this group.