bluuebunny/crossref_metadata_2025 huggingface dataset:
O73: IMPROVING CONSENT WITH A VISUAL TOOL FOR COMMUNICATING SURGICAL RISKS
Authors: Tingle SJ , Ramsingh JK , Bliss RD , Truran PP
Published: April 2021

Introduction

Patients must understand the risks of a procedure to provide valid consent. Guidance from the General Medical Council and Royal College of Surgeons of England highlights that surgeons need to communicate risks in a way that patients can understand, and both institutions specifically mention the use of written information. We aimed to improve communication of surgical risks to patients undergoing thyroid surgery.

Method

Over 3 months, all patients undergoing thyroid surgery in a tertiary referral centre were included (n=51). Participants were given a 10 point questionnaire after the consent process. Each question had 4 options (very common, common, uncommon and rare) and tested participant understanding of surgical risks. Our intervention was a single page annotated graphic, which used a traffic-light system to explain surgical risks.

Result

When consented prior to our intervention (n=28), patient understanding of the magnitude of surgical risks was poor; median questionnaire score was 4.5 out of 10, and for some questions <15% of participants selected the correct answer. Following introduction of our surgical risk tool (n=23) median overall participant score increased from 4.5 (range 2-7) to 8.0 (4-10) out of 10 (P<0.0001; Mann-Whitney U test).

Conclusion

Patients must understand the risks of an operation, and the magnitude of those risks, in order to provide valid consent. Addition of a visual surgical risk tool enabled us to increase patient understanding of surgical risks, improving the consent process. This has implications not just for thyroid surgery, but for any procedure requiring consent.

Take-home message

Clear communication of surgical risks is essential to obtain valid consent. The use of a visual surgical risk tool increases patient understanding of risks, and therefore improves the consent process.
P1: THE VITAL STUDY: A FEASIBILITY STUDY OF A RANDOMISED CONTROLLED TRIAL TO EXAMINE IF VIRTUAL REALITY TECHNOLOGY CAN IMPROVE SURGICAL TRAINING IN SIERRA LEONE
Authors:   WS Bolton on behalf of Leeds NIHR Global Health research Group in Surgical Technologies
Published: April 2021

Introduction

Training surgeons is expensive and relies on expert supervision. Virtual reality (VR) may enhance acquisition of knowledge and skills. There is limited evidence on the effectiveness of VR in low and middle-income countries (LMICs). The purpose of this study was to evaluate the technical feasibility of mobile phone VR in LMICs and the feasibility of conducting a full-scale randomised controlled trial.

Method

A prospective randomised controlled feasibility study was conducted. Surgical trainees were recruited from a government teaching hospital in Freetown in November 2019. Participants were randomised 1:1 VR vs non-VR. These were given one-week prior to a two-day hands-on course on lower limb amputation. The VR training involved two 30-minute modules consisting of narrated live surgery videos. Feasibility outcomes included recruitment rates and VR intervention fidelity and acceptability.

Result

Thirty participants were randomised to the VR group (n=15) or control group (n=15). Of these, 29 (96.7%) participants completed the course. The recruitment period required was two days. Intervention adherence exceeded defined success rates with 100% of participants completing the intervention. There was no unblinding. Compared to controls, the VR group rated statistically significantly higher engagement during the course in 4/6 domains, increased perceived learning in 5/5 domains and increased engagement with pre-course learning in in 4/6 domains.

Conclusion

VR is technically feasible in an LMIC setting and improves engagement and perceived learning. With minor modifications to the intervention and assessments, a full-scale trial is feasible. Further exploration is required to determine the best outcome measures to demonstrate effect.

Take-home message

VR is technically feasible in an LMIC setting and improves engagement and perceived learning. Now we need to explore if it can improve surgical knowledge and skill acquisition on a large scale.
P5: EFFECT OF VITAMIN C AND COLD ON GROWTH FACTOR RELEASE FROM PLATELET-RICH PLASMA
Authors: Tomouk T , Talaat S , Smith O , Mosahebi A
Published: April 2021

Introduction

Platelet-rich plasma (PRP) has gathered great momentum in surgery. The main outcome of the study was to assess whether there was a difference in growth factor release from PRP with addition of vitamin C, cooling, or both vitamin C and cooling.

Method

Blood samples from 10 volunteers were centrifuged to produce PRP. Activated autologous thrombin was produced from platelet-poor plasma (PPP), which was added to PRP to activate it. PRP from each participant was then divided by activation method into three groups: A) cold pack only; B) vitamin C only; C) cold pack/vitamin C. Growth factor quantification was performed for human VEGF, IGF-1 and PDGF-AB using enzyme-linked immunosorbent assays.

Result

At 24 hours, VEGF concentration in the cold group was significantly higher cf. the vitamin C group (p=0.02) and the cold/vit C group (p<0.01), whereas IGF concentration in the cold group was significantly higher cf. the vitamin C group (p=0.02) but not the cold/vit C group. At 1 hour and 24 hours, PDGF concentration in the cold group was significantly higher cf. both the vitamin C group (p<0.01) and the cold/vit C group (p=0.02 and p<0.0001 respectively).

Conclusion

Cooling lead to increased growth factor release at 24 hours, indicating that cooling may lead to sustained release of growth factors. There was a trend for PRP treated with vitamin C to remain in a gel-like consistency rather than clot. This may prove useful in clinical practice where currently activated PRP is constrained to topical application only due to its consistency.

Take-home message

Cooling may lead to sustained release of growth factors from platelet-rich plasma, whereas the addition of vitamin C may provide opportunity for injectable activated PRP.
P6: ANTIPLATELET AND ANTICOAGULANT USE IN RANDOMISED TRIALS OF PATIENTS UNDERGOING ENDOVASCULAR INTERVENTION FOR PERIPHERAL ARTERIAL DISEASE: SYSTEMATIC REVIEW
Authors: Qureshi MI , Li HL , Ambler GK , Wong KHF , Dawson S , Chaplin K , Cheng V , Hinchliffe RJ , Twine CP
Published: April 2021

Introduction

Guideline recommendations for antithrombotic (antiplatelet and anticoagulant) therapy during and after endovascular intervention are patchy and conflicted, in part due to a lack of evidence. The aim of this systematic review was to examine the antithrombotic specifications in randomised trials for peripheral arterial endovascular intervention.

Method

This review was conducted according to PRISMA guidelines. Randomised trials including participants with peripheral arterial disease undergoing endovascular arterial intervention were included. Trial methods were assessed to determine whether an antithrombotic protocol had been specified, its completeness, and the agent(s) prescribed. Antithrombotic protocols were classed as periprocedural (preceding/during intervention), immediate postprocedural (up to 14 days following intervention) and maintenance postprocedural (therapy continuing beyond 14 days). Trials were stratified according to type of intervention.

Result

Ninety-four trials were included. Only 29% of trials had complete periprocedural antithrombotic protocols, and 34% had complete post-procedural protocols. In total, 64 different periprocedural protocols, and 51 separate postprocedural protocols were specified.

Antiplatelet monotherapy and unfractionated heparin were the most common choices of regimen in the periprocedural setting, and dual antiplatelet therapy (55%) was most commonly utilised postprocedure. There is an increasing tendency to use dual antiplatelet therapy with time or for drug-coated technologies.

Conclusion

Randomised trials comparing different types of peripheral endovascular arterial intervention have a high level of heterogeneity in their antithrombotic regimens, and there has been an increasing tendency to use dual antiplatelet therapy over time. Antiplatelet regimes need to be standardised in trials comparing endovascular technologies.

Take-home message

To determine the benefits of any endovascular intervention within a randomised trial, antithrombotic regimens should be standardised to prevent confounding. This systematic review demonstrates a high level of heterogeneity of antithrombotic prescribing in randomised trials of endovascular intervention, and an increasing tendency to utilise dual antiplatelet therapy, despite a lack of evidence of benefit, but an increased risk of harm.
P11: NEAR INFRARED FLUORESCENT CHOLANGIOGRAPHY IN LAPAROSCOPIC CHOLECYSTECTOMY: A SINGLE CENTRE FEASIBILITY STUDY. THE OPTIMUM DOSING REGIME, LIMITATIONS AND WHERE NEXT?
Authors: Armstrong G , Toogood G , Jayne DG , Smith AM
Published: April 2021

Introduction

This study explored near-infrared fluorescent cholangiography (NIRFC) with Indocyanine Green (ICG) during laparoscopic cholecystectomy (LC) surgery in a tertiary referral hepatobiliary unit. ICG binds to albumin and is excreted in bile. NIRFC utilises the fluorescent and excretory properties of ICG to provide dynamic extrahepatic bile duct mapping during LC.

Method

Non-randomised single centre feasibility study. Twenty-two participants were sequentially allocated to four dosing subgroups prior to NIRFC assisted LC. Each received a single intravenous dose of ICG prior to LC with the Stryker Novadaq NIR laparoscope. The biliary anatomy was assessed with NIRFC at three time-points, detection was compared to radiological cholangiogram where available and surgeon satisfaction was assessed.

Result

Eight participants received 2.5mg ICG 20-40min before surgery, four 0.25mg/kg 20-40min, five 90min – 180min and five 12 – 36 hour pre-operatively. Average age 50 years (S.D±15), BMI 27.5m2 (S.D±3.6), 6/22 were acute LC procedures. The prolonged dosing interval produced increased extrahepatic biliary structure identification (p = 0.016), reduced noise to signal ratio and was consistently preferred by the operating surgeon. NIRFC was inferior to radiological cholangiogram (n = 10) (p = 0.014) for bile duct mapping. We observed iatrogenic bile spillage saturating the field and obscuring structure differentiation and peri-hilar inflammation impeding fluorescent detection in acute LC.

Conclusion

The dosing regimen 0.25mg/kg ICG 12 to 36 hours prior to surgery provides optimum NIRFC structure visualisation. Fluorescent tissue penetrance is limited in acute peri-hilar inflammation. More research in to the efficiency of NIRFC in emergency LC is required.

Take-home message

An intravenous dose of 0.25mg/kg of Indocyanine Green 12 to 36 hours before surgery is the optimum dosing regimen for increased extra-hepatic bile duct structures with near infrared fluorescent cholangiography. The role of NIRFC in acute laparoscopic cholecystectomy surgery remains ill-defined.
P21: PREVENTING DEHYDRATION IN LOOP ILEOSTOMY: RESULTS FROM A PPI GROUP TO ASSESS ACCEPTABILITY OF DAILY DOUBLE STRENGTH REHYDRATION SALTS (DIORALYTE™) AND PATIENT OPINIONS ON IMPORTANCE OF THIS AS AN AREA OF RESEARCH
Authors: Borucki JP , Hernon JM , Stearns AT
Published: April 2021

Introduction

Dehydration is a common problem amongst colorectal cancer patients who are defunctioned with loop ileostomy. This is known to lead to significant morbidity including acute kidney injury, hospital readmission and non-commencement or non-completion of chemotherapy. This institution plans to run a trial looking into preventing this with oral rehydration salts and formed a patient and public involvement (PPI) group to inform trial design and assess patient opinion on importance of this area of research.

Method

Five patients were recruited to the PPI group and a recorded semi-structured group interview was conducted. Patients were invited to try the rehydration salts and asked questions related to trial design and importance of research. The recording was transcribed and thematically analysed by the primary researcher. A consultant surgeon was present to ensure any medical issues raised were dealt with correctly.

Result

Three participants had experienced problems with their stoma. The main themes identified were; social embarrassment, behaviour modification, high outputs of stomas, fear of non-closure. The participants were unaware of dehydration related complications but felt that they were of high importance when provided with relevant information. Participants tasted the oral rehydration salts and expressed preference for mixing them with fruit flavoured squash. No specific barriers were identified in participation and patients were highly motivated to engage with the proposed study.

Conclusion

Patients are motivated and believe this to be a worthwhile area of research. Daily double strength rehydration salts are an acceptable intervention with few barriers to participation.

Take-home message

Dehydration in patients defunctioned with loop ileostomy is a significant cause of morbidity. Patients are highly motivated to engage in research into preventing this and find daily double strength rehydration salts is an acceptable intervention.
P22: CONSERVATIVE MANAGEMENT OF NECK OF FEMUR FRACTURES
Authors: Tan S , Hoggett L , Choudry Q , Aithal S , Bokhari A
Published: April 2021

Introduction

According to NICE CG124, the gold standard of treatment for neck of femur (NOF) fractures is operative management on the day or day after admission. In practice, this is not always achievable depending on various factors, e.g. patient preference, clinical condition and theatre availability, with a further subset of patients undergoing conservative management.

Method

A retrospective analysis was performed on all NOF fractures managed non-operatively at a single centre from January 2017 to August 2019 by case notes analysis and review of radiographical images. Demographics, fracture type, pre-fracture mobility status, co-morbidities, mortality and Nottingham Hip Fracture Score (NHFS) are reported. Where applicable, our dataset is correlated with the National Hip Fracture Database for comparison.

Result

24 patients were included in the study period, with a mean age of 79.9 years (range 54-99 years) and male:female ratio of 0.85:1. The mean NHFS (n=18) was 5.7 (range 3-8) and at least 62.5% (n=15) were deemed unfit for surgery or arrested pre-operatively. Conservatively managed NOF fractures are associated with a 30-day mortality of 41.7% compared to the centre average of 8.2% and national average of 6.9% for all NOF fractures. Overall mortality within 1 year is 95.5% (n=22).

Conclusion

Our study confirms that the conservative management of NOF fractures is associated with high mortality, however it may be the only treatment option acceptable in patients who are limited by unfavourable clinical conditions. Therefore, the decision for conservative management in NOF fractures requires careful consideration with the need for an established decision-making pathway.

Take-home message

The conservative management of neck of femur fractures is associated with high mortality, therefore requires careful consideration with the need for an established decision-making pathway.
P27: INTRODUCTION OF A PILOT VIRTUAL FRACTURE CLINIC: A TIME AND COST ANALYSIS
Authors: McCarthy A , Muller L , O'Shea K , Keeling P
Published: April 2021

Introduction

The British Orthopaedic Association Standards for Trauma and Orthopaedics(BOAST) have produced guidelines advising that all patients be reviewed by an orthopaedic consultant within 72 hours of presentation. However, data from traditional fracture clinics rarely fulfil this criterion. Furthermore, data from the National Health Service(NHS) has determined that traditional fracture clinics have become unfit for purpose with low patient satisfaction rates, excessive waiting times and over 6.9 million missed appointments every year. Our aim is to test the feasibility of a virtual fracture clinic(VFC) with a view to reducing service costs and improving adherence to BOAST guidelines specified timeline for orthopaedic consultant review.

Method

A retrospective analysis of 103 patients referred to our pilot VFC from January 1st to 31st 2019 was carried out. We included shoulder dislocations, clavicle injuries, simple distal radius fractures, radial head fractures, metacarpal and metatarsal injuries, undisplaced fractures of the medial and lateral malleolus of the ankle and soft tissue injuries. The primary outcome measured time from presentation to review by an orthopaedic consultant. A cost analysis was also performed to estimate the overheads and potential savings associated with VFC introduction. Statistical analysis was done via SPSS.

Result

Following VFC establishment, time from ED presentation to review by orthopaedic consultant reduced from a mean of 229 hours to 72 hours(P=0.0001). Cost analysis demonstrated that the VFC created savings of €3170 per week, amounting to projected savings of €38,040.

Conclusion

VFC has the potential to improve clinical performance while delivering substantial financial savings.

Take-home message

Virtual fracture clinic improves patients review times bringing them in line with BOAST guidelines while providing significant reductions in overheads leading to potential savings of over 38,000 euro.
P32: POST-OPERATIVE RELATIVE PARATHORMONE DECLINE (ΔPTH%) AND ABSOLUTE PARATHORMONE DECLINE (ΔPTH) LEVELS ARE BETTER MARKERS OF SYMPTOMATIC HYPOCALCEMIA FOLLOWING TOTAL THYROIDECTOMY THAN POST-OPERATIVE PTH ALONE
Authors: Ravindhran B , Rajan S , Mohan L N
Published: April 2021

Introduction

Hypocalcemia is a frequent complication following thyroidectomy which can delay discharge and increase overall treatment expenditure. We aimed to assess the predictive value of absolute and relative intact Parathormone(iPTH) decline levels as reliable markers of post-operative hypocalcemia.

Method

This prospective study included 95 consecutive patients at our tertiary care centre. Patients underwent either Total Thyroidectomy(TT), TT+Central Neck Dissection(CND) or TT+CND+Modified Radical Neck Dissection(MRND). iPTH levels were measured four hours after surgery and the following morning after surgery(POD 1). iPTH, absolute iPTH decline(ΔPTH) and relative iPTH decline(ΔPTH%) were calculated and correlated with hypocalcemia. Comparisons between groups were measured by chi-square test, Fischer's exact test and Mann-Whitney U test.

Result

Of the 95 patients, 59 had malignant disease, while 36 patients had benign histopathology. TT was performed in 69 patients, TT+CCLND in 7, and TT+CCLND+MRND in 19. 32.6% of patients(n=31) had biochemical hypocalcemia and 20%(n=19) had symptomatic hypocalcemia. The mean calcium of the cohort on Post-operative day(POD)-1 was 8.3±0.66(range=6.5-9.9) and POD-3 was 8.4±0.69(range=6.3–10.7). Median PTH, measured 4 hours after surgery was 24pg/ml(IQR–23.4;range 2.5–85.5), and measured on POD-1 was 28pg/ml(IQR–27.6;range=2-79). The ΔPTH(U=206;p<0.001) & ΔPTH% (U=127;p<0.001) were significantly higher in patients with symptomatic hypocalcemia. A ΔPTH% of 20%(sensitivity=84%;specificity=91%) and ΔPTH of 3.75 pg/ml(sensitivity = 74%; specificity=87%) were good predictors of symptomatic hypocalcemia.

Conclusion

Post-operative ΔPTH and ΔPTH% are reliable predictors of hypocalcemia following thyroid surgery and have the potential to facilitate a safe early discharge for patients undergoing TT. 20% fall in the PTH level(ΔPTH%) can be useful as a marker of hypocalcemia.

Take-home message

Post-operative ΔPTH and ΔPTH% are better predictors of hypocalcemia following thyroid surgery than a single value of post-operative PTH alone.
P35: BODY COMPOSITION: ASSOCIATION WITH OPERATIVE AND ONCOLOGIC OUTCOMES IN THE MODERN MANAGEMENT OF RETROPERITONEAL SARCOMA – RESULTS OF A FEASIBILITY STUDY
Authors: McIntyre TV , Elliott JA , Boyle E , Donlon NE , Barnes M , Connelly TM , Hayden U , Hickey N , Gillis AE , Ridgway PF
Published: April 2021

Introduction

Sarcopenia and obesity in cancer may confer negative outcomes, but their prevalence and impact on modern regimens for retroperitoneal sarcoma (RPS) have not been systematically studied. Sarcopaenia and obesity measurements by computed tomography (CT) measurements at L3 may be confounded by the disease process itself. The aim of this study is to determine feasibility in providing the prevalence of sarcopenia and visceral obesity in the management of RPS to assess their potential impact on operative and oncologic outcomes.

Method

Consecutive sample patients undergoing treatment for RPS from our database were retrospectively studied. Total, subcutaneous and visceral fat areas (VFA), myosteatosis, skeletal muscle index (SMI) lean body mass and fat mass were determined at diagnosis by CT. Sarcopenia will be defined by CT at L3 as SMI <52.4 cm2/m2 for males and SMI <38.5 cm2/m2 for females, and visceral obesity as VFA >163.8cm2 for men and >80.1cm2 for women.

Result

40 consecutive patients, 21 [52.5%] female, 56.7±15.1 years, were studied. The most common histologic types were leiomyosarcoma (8 [20.0%]), dedifferentiated liposarcoma (7 [17.5%]), well differentiated liposarcoma (7 [17.5%]), myxoid liposarcoma (4 [10.0%]). Mean±SD body composition measures were: lean body mass, 50.4±12.0 kg; total fat mass, 27.2±8.6 kg; visceral fat area, 148.5±120.2 cm2; subcutaneous fat area, 222.2±20.4 cm2; myosteatosis, 8.9±7.3 cm2.

Conclusion

Assessment of body composition among patients with RPS is feasible. Analysis to identify the prevalence and significance of sarcopenia and visceral obesity and its relationship to operative and oncologic outcomes is ongoing.

Take-home message

Assessment of body composition in RPS is feasible and its effect on outcomes is under investigation
P36: SOMATIC SYMPTOM DISORDER (SSD) AND ABDOMINAL PAIN: INCREASED OPIOID PRESCRIBING IN SURGICAL PATIENTS
Authors: Campbell C , Stieler M , Pockney P , Shah K , Thirugnanasundralingam V , Spittal M , Carter G
Published: April 2021

Introduction

Undifferentiated pain, and pain out of proportion of diagnosed pathology are sources of frustration to clinician and patient. SSD is a DSM-V diagnosis that has consolidated the previous diagnoses of psychogenic pain. It is a health anxiety condition, where sufferers experience multiple somatic symptoms which cause anxiety and distress. This anxiety results in frequent ED and GP presentations, extensive investigations, and increased opioid prescription. However, opioids do little to alleviate symptoms. Treatment should focus on underlying anxiety and depression.

Population studies show SSD prevalence to be 15-20%, however SSD has never been studied in the surgical population. We hypothesized that the rates of SSD in the surgical population reflects that in primary care, and that SSD sufferers are more likely to be prescribed opioid analgesia.

Method

Adult patients admitted with abdominal pain of any non-traumatic aetiology to the Acute General Surgical Unit at a major tertiary hospital are being screened for SSD using the PHQ-15 questionnaire, and opioid prescription is being recorded.

Result

400 participants have been recruited with a total SSD prevalence of 20%. Opioid prescribing rises sharply with SSD diagnosis. The average opioid prescription appears to be 3 times higher in patients with SSD compared to those without.

Conclusion

Our data confirms an SSD prevalence of 20% in the surgical population. This is associated with increased opioid prescription. Early recognition of SSD and implementation of appropriate treatment could reduce hospital presentations, admissions and opioid prescription. We will continue recruitment to 800 participants by March 2020.

Take-home message

SSD is common in all populations, and results in increased hospital presentations, admissions and opioid prescription. Early recognition and implementation of appropriate treatment may reduce healthcare burden, improve patient outcomes, and reduce opioid prescription.
Neuronal deletion of Wwox, associated with WOREE syndrome, causes epilepsy and myelin defects
Authors: Repudi Srinivasarao , Steinberg Daniel J , Elazar Nimrod , Breton Vanessa L , Aquilino Mark S , Saleem Afifa , Abu-Swai Sara , Vainshtein Anna , Eshed-Eisenbach Yael , Vijayaragavan Bharath , Behar Oded , Hanna Jacob J , Peles Elior , Carlen Peter L , Aqeilan Rami I
Published: April 2021

WWOX-related epileptic encephalopathy (WOREE) syndrome caused by human germline bi-allelic mutations in WWOX is a neurodevelopmental disorder characterized by intractable epilepsy, severe developmental delay, ataxia and premature death at the age of 2–4 years. The underlying mechanisms of WWOX actions are poorly understood.

In the current study, we show that specific neuronal deletion of murine Wwox produces phenotypes typical of the Wwox-null mutation leading to brain hyperexcitability, intractable epilepsy, ataxia and postnatal lethality. A significant decrease in transcript levels of genes involved in myelination was observed in mouse cortex and hippocampus. Wwox-mutant mice exhibited reduced maturation of oligodendrocytes, reduced myelinated axons and impaired axonal conductivity. Brain hyperexcitability and hypomyelination were also revealed in human brain organoids with a WWOX deletion.

These findings provide cellular and molecular evidence for myelination defects and hyperexcitability in the WOREE syndrome linked to neuronal function of WWOX.
Sustainability of community-managed small town and rural water systems in northern Ghana: lessons from Upper West Region
Authors: Osumanu Issaka Kanton , Zumayelleh Emmanuel Ankamah , Kosoe Enoch Akwasi
Published: April 2021

This study assessed sustainability of small town and rural water services in northern Ghana using lessons from Jirapa Municipality. A case study design, deploying mixed methods, was employed. Data were obtained from household questionnaires administration and in-depth interviews with community leaders and institutional stakeholders in the water sector. The results revealed that, though access to potable water has increased since the introduction of community-management of water services in Jirapa Municipality, there are still difficulties in terms of adequate water supply. Sustainability challenges revealed by the study are managerial and technical, including ineffective water-management committees, inadequate operations and maintenance capacity, inadequate funds to maintain facilities and lack of continuing support. The study concludes that the apparently improved access to potable water in the Municipality may be short-lived. To improve and sustain water services, water-management committees should be established and trained in administration, operations, maintenance and tariff setting. Also, innovative ways, such as establishing a ‘water-management fund’, should be used to provide continuing support to communities.
Perceptual Quality of Nonesterified Fatty Acids Varies with Fatty Acid Chain Length
Authors: Cheon Eunjin , Mattes Richard D
Published: April 2021

Nonesterified fatty acids (NEFA) are effective taste stimuli. The quality they impart has not been well characterized. Sourness, and “fattiness” have been reported, but an irritation component has also been described and how these transition with gradations of aliphatic chain length has not been systematically studied. This study examined intensity and quality ratings of NEFA ranging from C2 to C18. Oral sites and the time course of sensations were also monitored. Given all NEFA contain carboxylic acid moieties capable of donating hydrogen ions, the primary stimulus for sour taste, testing was conducted with and without sour adaptation to explore the contribution of sour taste across the range of NEFA. Short-chain NEFA (C2–C6) were rated as predominantly sour, and this was diminished in C2 and C4 by sour adaptation. Medium-chain NEFA (C8–C12) were rated as mainly irritating with long-chain NEFA (C18) described mostly as bitter. The latter may reflect the lack of “fatty” lexicon to describe the sensation. Short-chain NEFA were mostly localized to the anterior tongue and were of rapid onset. The sensation from medium-chain NEFA was attributed to the lateral tongue, whereas medium- and long-chain NEFA sensations were predominantly localized to the back of the tongue and throat and had a longer lag time. The findings indicate there is a systematic transition of NEFA taste quality and irritation with increments in chain length and this is consistent with multiple modes of transduction.
Drebrin attenuates atherosclerosis by limiting smooth muscle cell transdifferentiation
Authors: Wu Jiao-Hui , Zhang Lisheng , Nepliouev Igor , Brian Leigh , Huang Taiqin , Snow Kamie P , Schickling Brandon M , Hauser Elizabeth R , Miller Francis J , Freedman Neil J , Stiber Jonathan A
Published: April 2021

Aims 

The F-actin-binding protein Drebrin inhibits smooth muscle cell (SMC) migration, proliferation, and pro-inflammatory signalling. Therefore, we tested the hypothesis that Drebrin constrains atherosclerosis.

Methods and results

SM22-Cre+/Dbnflox/flox/Ldlr−/− (SMC-Dbn−/−/Ldlr−/−) and control mice (SM22-Cre+/Ldlr−/−, Dbnflox/flox/Ldlr−/−, and Ldlr−/−) were fed a western diet for 14–20 weeks. Brachiocephalic arteries of SMC-Dbn −/−/Ldlr−/− mice exhibited 1.5- or 1.8-fold greater cross-sectional lesion area than control mice at 14 or 20 weeks, respectively. Aortic atherosclerotic lesion surface area was 1.2-fold greater in SMC-Dbn−/−/Ldlr−/− mice. SMC-Dbn−/−/Ldlr−/− lesions comprised necrotic cores that were two-fold greater in size than those of control mice. Consistent with their bigger necrotic core size, lesions in SMC-Dbn−/− arteries also showed more transdifferentiation of SMCs to macrophage-like cells: 1.5- to 2.5-fold greater, assessed with BODIPY or with CD68, respectively. In vitro data were concordant: Dbn−/− SMCs had 1.7-fold higher levels of KLF4 and transdifferentiated to macrophage-like cells more readily than Dbnflox/flox SMCs upon cholesterol loading, as evidenced by greater up-regulation of CD68 and galectin-3. Adenovirally mediated Drebrin rescue produced equivalent levels of macrophage-like transdifferentiation in Dbn−/− and Dbnflox/flox SMCs. During early atherogenesis, SMC-Dbn−/−/Ldlr−/− aortas demonstrated 1.6-fold higher levels of reactive oxygen species than control mouse aortas. The 1.8-fold higher levels of Nox1 in Dbn−/− SMCs were reduced to WT levels with KLF4 silencing. Inhibition of Nox1 chemically or with siRNA produced equivalent levels of macrophage-like transdifferentiation in Dbn−/− and Dbnflox/flox SMCs.

Conclusion 

We conclude that SMC Drebrin limits atherosclerosis by constraining SMC Nox1 activity and SMC transdifferentiation to macrophage-like cells.
Transcriptomic Signatures of Ageing Vary in Solitary and Social Forms of an Orchid Bee
Authors: Séguret Alice , Stolle Eckart , Fleites-Ayil Fernando A , Quezada-Euán José Javier G , Hartfelder Klaus , Meusemann Karen , Harrison Mark C , Soro Antonella , Paxton Robert J
Published: April 2021

Eusocial insect queens are remarkable in their ability to maximize both fecundity and longevity, thus escaping the typical trade-off between these two traits. Several mechanisms have been proposed to underlie the remolding of the trade-off, such as reshaping of the juvenile hormone (JH) pathway, or caste-specific susceptibility to oxidative stress. However, it remains a challenge to disentangle the molecular mechanisms underlying the remolding of the trade-off in eusocial insects from caste-specific physiological attributes that have subsequently arisen. The socially polymorphic orchid bee Euglossa viridissima represents an excellent model to address the role of sociality per se in longevity as it allows direct comparisons of solitary and social individuals within a common genetic background. We investigated gene expression and JH levels in young and old bees from both solitary and social nests. We found 902 genes to be differentially expressed with age in solitary females, including genes involved in oxidative stress, versus only 100 genes in social dominant females, and 13 genes in subordinate females. A weighted gene coexpression network analysis further highlights pathways related to ageing in this species, including the target of rapamycin pathway. Eleven genes involved in translation, apoptosis, and DNA repair show concurrent age-related expression changes in solitary but not in social females, representing potential differences based on social status. JH titers did not vary with age or social status. Our results represent an important step in understanding the proximate mechanisms underlying the remodeling of the fecundity/longevity trade-off that accompanies the evolutionary transition from solitary life to eusociality.
The Codon Usage Code for Cotranslational Folding of Viral Capsids
Authors: Pintó Rosa M , Bosch Albert
Published: April 2021

Codon bias is common to all organisms and is the result of mutation, drift, and selection. Selection for the efficiency and accuracy of translation is well recognized as a factor shaping the codon usage. In contrast, fewer studies report the control of the rate of translation as an additional selective pressure influencing the codon usage of an organism. Experimental molecular evolution using RNA virus populations is a powerful tool for the identification of mechanisms underlying the codon bias. Indeed, the role of deoptimized codons on the cotranslational folding has been proven in the capsids of two fecal-orally transmitted picornaviruses, poliovirus, and the hepatitis A virus, emphasizing the role of the frequency of codons in determining the phenotype. However, most studies on virus codon usage rely only on computational analyses, and experimental studies should be encouraged to clearly define the role of selection on codon evolution.
Chromosomal-Level Reference Genome of the Neotropical Tree Jacaranda mimosifolia D. Don
Authors: Wang Mingcheng , Zhang Lei , Wang Zhiqiang
Published: April 2021

Jacaranda mimosifolia D. Don is a deciduous tree widely cultivated in the tropics and subtropics of the world. It is famous for its beautiful blue flowers and pinnate compound leaves. In addition, this tree has great potential in environmental monitoring, soil quality improvement, and medicinal applications. However, a genome resource for J. mimosifolia has not been reported to date. In this study, we constructed a chromosome-level genome assembly of J. mimosifolia using PacBio sequencing, Illumina sequencing, and Hi-C technology. The final genome assembly was ∼707.32 Mb in size, 688.76 Mb (97.36%) of which could be grouped into 18 pseudochromosomes, with contig and scaffold N50 values of 16.77 and 39.98 Mb, respectively. A total of 30,507 protein-coding genes were predicted, 95.17% of which could be functionally annotated. Phylogenetic analysis among 12 plant species confirmed the close genetic relationship between J. mimosifolia and Handroanthus impetiginosus. Gene family clustering revealed 481 unique, 103 significantly expanded, and 16 significantly contracted gene families in the J. mimosifolia genome. This chromosome-level genome assembly of J. mimosifolia will provide a valuable genomic resource for elucidating the genetic bases of the morphological characteristics, adaption evolution, and active compounds biosynthesis of J. mimosifolia.
A Targeted Gene Knockout in Drosophila
Authors: Rong Yikang S , Golic Kent G
Published: April 2021

We previously described a method for targeted homologous recombination at the yellow gene of Drosophila melanogaster. Because only a single gene was targeted, further work was required to show whether the method could be extended to become generally useful for gene modification in Drosophila. We have now used this method to produce a knockout of the autosomal pugilist gene by homologous recombination between the endogenous locus and a 2.5-kb DNA fragment. This was accomplished solely by tracking the altered genetic linkage of an arbitrary marker gene as the targeting DNA moved from chromosome X or 2 to chromosome 3. The results indicate that this method of homologous recombination is likely to be generally useful for Drosophila gene targeting.
A Simple Formula Useful for Positional Cloning
Authors: Durrett Richard T , Chen Kai-Yi , Tanksley Steven D
Published: April 2021

We derive a formula for the distribution of the length T of the recombination interval containing a target gene and using N gametes in a region where R kilobases correspond to 1 cM. The formula can be used to calculate the number of meiotic events required to narrow a target gene down to a specific interval size and hence should be useful for planning positional cloning experiments. The predictions of this formula agree well with the results from a number of published experiments in Arabidopsis.
Investigating the Probability of Sign Inconsistency in the Regression Coefficients of Markers Flanking Quantitative Trait Loci
Authors: Hwang J T Gene , Nettleton Dan
Published: April 2021

Estimates of the locations and effects of quantitative trait loci (QTL) can be obtained by regressing phenotype on marker genotype. Under certain basic conditions, the signs of regression coefficients flanking QTL must be the same. There is no guarantee, however, that the signs of the regression coefficient estimates will be the same. We use sign inconsistency to describe the situation in which there is disagreement between the signs of the estimated regression coefficients flanking QTL. The presence of sign inconsistency can undermine the effectiveness of QTL mapping strategies that presume intervals whose markers have regression coefficient estimates of differing sign to be devoid of QTL. This article investigates the likelihood of sign inconsistency under various conditions. We derive an analytic expression for the approximate probability of sign inconsistency in the single-QTL case. We also examine sign inconsistency probabilities when multiple QTL are present through simulation. We have discovered that the probability of sign inconsistency can be unacceptably high, even when the conditions for QTL detection are otherwise quite favorable.
Host Genotype Determines Cytoplasmic Incompatibility Type in the Haplodiploid Genus Nasonia
Authors: Bordenstein Seth R , Uy Julieanne J , Werren John H
Published: April 2021

In haplodiploid species, Wolbachia-induced cytoplasmic incompatibility (CI) can be expressed in one of two ways: as a “conversion” of diploid fertilized eggs into haploid males or as embryonic mortality. Here we describe CI-type variation within the parasitic wasp genus Nasonia and genetically analyze the basis of this variation. We reach four main conclusions: (i) CI is expressed primarily as conversion in N. vitripennis, but as embryonic mortality in the sibling species N. giraulti and N. longicornis; (ii) the difference in CI type between N. giraulti (mortality) and N. vitripennis (conversion) is determined by host nuclear genotype rather than by Wolbachia differences; (iii) N. vitripennis “conversion genes” are recessive in hybrid females; and (iv) a difference in CI level between the sibling species N. giraulti and N. longicornis is due to the different Wolbachia infections in the species rather than to the host genotype. These results show that host nuclear genes can influence the type of CI present in a species. On the basis of these findings, we propose a model for how different CI types evolve in haplodiploids due to selection on nuclear genes modifying CI.
Experimental Prediction of the Evolution of Cefepime Resistance From the CMY-2 AmpC β-Lactamase
Authors: Barlow Miriam , Hall Barry G
Published: April 2021

Understanding of the evolutionary histories of many genes has not yet allowed us to predict the evolutionary potential of those genes. Intuition suggests that current biochemical activity of gene products should be a good predictor of the potential to evolve related activities; however, we have little evidence to support that intuition. Here we use our in vitro evolution method to evaluate biochemical activity as a predictor of future evolutionary potential. Neither the class C Citrobacter freundii CMY-2 AmpC β-lactamase nor the class A TEM-1 β-lactamase confer resistance to the β-lactam antibiotic cefepime, nor do any of the naturally occurring alleles descended from them. However, the CMY-2 AmpC enzyme and some alleles descended from TEM-1 confer high-level resistance to the structurally similar ceftazidime. On the basis of the comparison of TEM-1 and CMY-2, we asked whether biochemical activity is a good predictor of the evolutionary potential of an enzyme. If it is, then CMY-2 should be more able than the TEMs to evolve the ability to confer higher levels of cefepime resistance. Although we generated CMY-2 evolvants that conferred increased cefepime resistance, we did not recover any CMY-2 evolvants that conferred resistance levels as high as the best cefepime-resistant TEM alleles.
Ectopic Expression of Inhibitors of Protein Phosphatase Type 1 (PP1) Can Be Used to Analyze Roles of PP1 in Drosophila Development
Authors: Bennett Daimark , Szöőr Balázs , Gross Sascha , Vereshchagina Natalia , Alphey Luke
Published: April 2021

We have identified two proteins that bind with high specificity to type 1 serine/threonine protein phosphatase (PP1) and have exploited their inhibitory properties to develop an efficient and flexible strategy for conditional inactivation of PP1 in vivo. We show that modest overexpression of Drosophila homologs of I-2 and NIPP1 (I-2Dm and NIPP1Dm) reduces the level of PP1 activity and phenotypically resembles known PP1 mutants. These phenotypes, which include lethality, abnormal mitotic figures, and defects in muscle development, are suppressed by coexpression of PP1, indicating that the effect is due specifically to loss of PP1 activity. Reactivation of I-2Dm:PP1c complexes suggests that inhibition of PP1 activity in vivo does not result in a compensating increase in synthesis of active PP1. PP1 mutants enhance the wing overgrowth phenotype caused by ectopic expression of the type II TGFβ superfamily signaling receptor Punt. Using I-2Dm, which has a less severe effect than NIPP1Dm, we show that lowering the level of PP1 activity specifically in cells overexpressing Punt is sufficient for wing overgrowth and that the interaction between PP1 and Punt requires the type I receptor Thick-veins (Tkv) but is not strongly sensitive to the level of the ligand, Decapentaplegic (Dpp), nor to that of the other type I receptors. This is consistent with a role for PP1 in antagonizing Punt by preventing phosphorylation of Tkv. These studies demonstrate that inhibitors of PP1 can be used in a tissue- and developmental-specific manner to examine the developmental roles of PP1.
Sry Expression Level and Protein Isoform Differences Play a Role in Abnormal Testis Development in C57BL/6J Mice Carrying Certain Sry Alleles
Authors: Albrecht Kenneth H , Young Maureen , Washburn Linda L , Eicher Eva M
Published: April 2021

Transfer of certain Mus domesticus-derived Y chromosomes (SryDOM alleles, e.g., SryPOS and SryAKR) onto the C57BL/6J (B6) mouse strain causes abnormal gonad development due to an aberrant interaction between the SryDOM allele and the B6-derived autosomal (tda) genes. For example, B6 XYPOS fetuses develop ovaries and ovotestes and B6 XYAKR fetuses have delayed testis cord development. To test whether abnormal testis development is caused by insufficient SryDOM expression, two approaches were used. First, gonad development and relative Sry expression levels were examined in fetal gonads from two strains of B6 mice that contained a single M. domesticus-derived and a single M. musculus-derived Sry allele (B6-YPOS,RIII and B6-YAKR,RIII). In both cases, presence of the M. musculus SryRIII allele corrected abnormal testis development. On the B6 background, SryPOS was expressed at about half the level of SryRIII whereas SryAKR and SryRIII were equally expressed. On an F1 hybrid background, both SryPOS and SryRIII expression increased, but SryPOS expression increased to a greater extent. Second, sexual development and Sry expression levels were determined in XX mice carrying a transgene expressing SryPOS controlled by POS-derived or MUS-derived regulatory regions. In both cases one B6 transgenic line was recovered in which XX transgenic mice developed only testicular tissue but cord development was delayed despite normal Sry transcriptional initiation and overexpression. For three transgenes where B6 XX transgenic mice developed as females, hermaphrodites, or males, the percentage of XX transgenic males increased on an F1 background. For the one transgene examined, Sry expression increased on an F1 background. These results support a model in which delayed testis development is caused by the presence of particular DOM SRY protein isoforms and this, combined with insufficient Sry expression, causes sex reversal. These results also indicate that at least one tda gene regulates Sry expression, possibly by directly binding to Sry regulatory regions.
A Bacterial Artificial Chromosome Contig Spanning the Major Domestication Locus Q in Wheat and Identification of a Candidate Gene
Authors: Faris Justin D , Fellers John P , Brooks Steven A , Gill Bikram S
Published: April 2021

The Q locus played a major role in the domestication of wheat because it confers the free-threshing character and influences many other agronomically important traits. We constructed a physical contig spanning the Q locus using a Triticum monococcum BAC library. Three chromosome walking steps were performed by complete sequencing of BACs and identification of low-copy markers through similarity searches of database sequences. The BAC contig spans a physical distance of ∼300 kb corresponding to a genetic distance of 0.9 cM. The physical map of T. monococcum had perfect colinearity with the genetic map of wheat chromosome arm 5AL. Recombination data in conjunction with analysis of fast neutron deletions confirmed that the contig spanned the Q locus. The Q gene was narrowed to a 100-kb segment, which contains an APETALA2 (AP2)-like gene that cosegregates with Q. AP2 is known to play a major role in controlling floral homeotic gene expression and thus is an excellent candidate for Q.
Comparison of a Brassica oleracea Genetic Map With the Genome of Arabidopsis thaliana
Authors: Lukens Lewis , Zou Fei , Lydiate Derek , Parkin Isobel , Osborn Tom
Published: April 2021

Brassica oleracea is closely related to the model plant, Arabidopsis thaliana. Despite this relationship, it has been difficult to both identify the most closely related segments between the genomes and determine the degree of genome replication within B. oleracea relative to A. thaliana. These difficulties have arisen in part because both species have replicated genomes, and the criteria used to identify orthologous regions between the genomes are often ambiguous. In this report, we compare the positions of sequenced Brassica loci with a known position on a B. oleracea genetic map to the positions of their putative orthologs within the A. thaliana genome. We use explicit criteria to distinguish orthologous from paralogous loci. In addition, we develop a conservative algorithm to identify collinear loci between the genomes and a permutation test to evaluate the significance of these regions. The algorithm identified 34 significant A. thaliana regions that are collinear with >28% of the B. oleracea genetic map. These regions have a mean of 3.3 markers spanning 2.1 Mbp of the A. thaliana genome and 2.5 cM of the B. oleracea genetic map. Our findings are consistent with the hypothesis that the B. oleracea genome has been highly rearranged since divergence from A. thaliana, likely as a result of polyploidization.
Mathematical Issues Arising From the Directed Mutation Controversy
Authors: Zheng Qi
Published: April 2021

During the past 14 years or so a large body of new evidence that supposedly supports the directed mutation hypothesis has accumulated. Interpretation of some of the evidence depends on mathematical reasoning, which can be subtler than it appears at first sight. This article attempts to clarify some of the mathematical issues arising from the directed mutation controversy, thereby offering alternative interpretations of some of the evidence.