Measurement of the Isolated Nuclear Two-Photon Decay in ^{72}Ge

The nuclear two-photon or double-gamma (2γ) decay is a second-order electromagnetic process whereby a nucleus in an excited state emits two gamma rays simultaneously. To be able to directly measure the 2γ decay rate in the low-energy regime below the electron-positron pair-creation threshold, we combined the isochronous mode of a storage ring with Schottky resonant cavities. The newly developed technique can be applied to isomers with excitation energies down to ∼100  keV and half-lives as short as ∼10  ms. The half-life for the 2γ decay of the first-excited 0^{+} state in bare ^{72}Ge ions was determined to be 23.9(6) ms, which strongly deviates from expectations.

Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants

Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus remains largely unclarified. We performed size-fractionated aerosol sampling (Andersen cascade impactor) and evaluated viral culturability in human cell lines (infectiousness), viral genetics, and host immunity in ambulatory participants with COVID-19. Sixty-one percent (27/44) and 50% (22/44) of participants emitted variant-specific culture-positive aerosols <10μm and <5μm, respectively, for up to 9 days after symptom onset. Aerosol culturability is significantly associated with lower neutralizing antibody titers, and suppression of transcriptomic pathways related to innate immunity and the humoral response. A nasopharyngeal Ct <17 rules-in ~40% of aerosol culture-positives and identifies those who are probably highly infectious. A parsimonious three transcript blood-based biosignature is highly predictive of infectious aerosol generation (PPV > 95%). There is considerable heterogeneity in potential infectiousness i.e., only 29% of participants were probably highly infectious (produced culture-positive aerosols <5μm at ~6 days after symptom onset). These data, which comprehensively confirm variant-specific culturable SARS-CoV-2 in aerosol, inform the targeting of transmission-related interventions and public health containment strategies emphasizing improved ventilation.

Effects of Multi-Month Dispensing on Clinical Outcomes: Retrospective Cohort Analysis Conducted in Kenya

Multi-month dispensing (MMD) has been widely adopted by national HIV programs as a key strategy for improving the quality of HIV care and treatment services while meeting the unique needs of diverse client populations. We assessed the clinical outcomes of clients receiving MMD in Kenya by conducting a retrospective cohort study using routine programmatic data in 32 government health facilities in Kenya. We included clients who were eligible for multi-month antiretroviral therapy (ART) dispensing for ≥ 3 months (≥ 3MMD) according to national guidelines. The primary exposure was enrollment into ≥ 3MMD. The outcomes were lost to follow-up (LTFU) and viral rebound. Multilevel modified-Poisson regression models with robust standard errors were used to compare clinical outcomes between clients enrolled in ≥ 3MMD and those receiving ART dispensing for less than 3 months (< 3MMD). A total of 3,501 clients eligible for ≥ 3MMD were included in the analysis, of whom 65% were enrolled in ≥ 3MMD at entry into the cohort. There was no difference in LTFU of ≥ 180 days between the two types of care (aRR 1.1, 95% CI 0.7-1.6), while ≥ 3MMD was protective for viral rebound (aRR 0.1 95% CI 0.0-0.2). As more diverse client-focused service delivery models are being implemented, robust evaluations are essential to guide the implementation, monitor progress, and assess acceptability and effectiveness to deliver optimal people-centered care.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

P14.85 Impact of the neuro-radiologist and neuro-surgeon in contouring with the neuro-oncologist on local relapse rates for brain metastases treated with stereotactic radiosurgery

BACKGROUND

The audit evaluates the value of MDT, including neuro-radiologist and neuro-surgeon, review of contouring carried out by a clinical oncologist in stereotactic radiosurgery (SRS).

MATERIAL AND METHODS

A sequential audit was conducted of all patients receiving intracranial SRS at our local institution for the first 22 months of a new SRS service. Lesions were contoured first by clinical oncologist then reviewed/edited by the MDT. The initial contour was compared with final contour using Jaccard conformity and geographical miss indices. The dosimetric impact of a contouring change was assessed using plan metrics to both original and final contour. The impact of the contouring review on local relapse, overall survival and radio necrosis rate was evaluated with at least 24 months follow up (24–46 months).

RESULTS

113 patients and 142 lesions treated over 22 months were identified. Mean JCI was 0.92 (0.32–1.00) and 38% needed significant editing (JCI&lt;0.95). Mean GMI was 0.03 (0.0–0.65) and 17% showed significant miss (GMI&gt;0.05). Resection cavities showed more changes, with lower JCI and higher GMI (p&lt;0.05). There was no significant improvement on JCI or GMI shown over time. Dosimetric analysis indicated a strong association of conformity metrics with PTV dose metrics; a 0.1 change in GTV conformity metric association with 6–17% change in dose to 95% of resulting PTV. Greater association was seen in resection cavity suggesting the geographical nature of a typical contouring error gives rise to greater potential change in dose. Clinical outcomes compared well with published series. Median survival was 20 months and local relapse free rate in the treated areas of 0.89 (0.8–0.94) at 40 months, and 0.9 (0.83–0.95) radio-necrosis free rate at 40 months with a median 17 months to developing radio-necrosis for those that did.

CONCLUSION

This work highlights that a MDT contour review adds significant value to SRS and the approach translates into reduced local recurrence rates at our local institution compared with previously published data. Radio-necrosis rates are below 10%. No improvement in clinical oncologist contouring over time was shown indicating a collaborative approach is needed regardless of experience of clinical oncologist. MDT input is recommended in particular in contouring of resection cavities.

A 410 MHz resonant cavity pickup for heavy ion storage rings

An improved design of a longitudinally sensitive resonant Schottky cavity pickup for the heavy ion storage rings of the Facility for Antiproton and Ion Research in Europe (FAIR) project is reported. The new detector has a higher measured Q value of ∼3000 and a higher simulated shunt impedance of 473.3 kΩ. It is possible to vary the sensitivity of the cavity with a motorized mechanism by inserting a dissipative blade during the operation based on experimental needs. Apart from a lower price tag, the new design features a more robust and production-friendly mechanical structure suitable for a series production in the future FAIR project. The manufactured cavity was built temporarily into the experimental storage ring and had delivered its first results using stored heavy ion beams. The structure, simulation results, and performance of this cavity are presented in this work.

Evaluation of urethral orifice cross-section dimensions following perineal urethrostomy in male cats

OBJECTIVES

The aims of this study were: (1) To evaluate the urethral orifice cross-section size immediately and 12 days post-operatively following a perineal urethrostomy procedure. (2) To assess the correlation between the cross-section size and stricture formation during a 6-month period following the perineal urethrostomy.

ANIMALS

Twenty-four male cats with feline lower urinary tract disease that failed to respond to medical treatment and underwent perineal urethrostomy.

MATERIALS AND METHODS

The urethral orifice cross-section size was estimated by the largest size of the urinary catheter that was possible to insert facilely through the urethrostomy site. The urethral orifice cross-section size was measured in three different times: Pre-operative (LUCpr), immediately post-operative (LUCi) and 12 days post-operative (LUCp). Urinary obstruction recurrence and urethrostomy site stricture formation were documented for 6 months after the surgical procedure. The probabilities for obstruction recurrence in cases of LUCi ≤ 8Fr and LUCi > 8Fr were calculated.

RESULTS

Urinary obstruction and urethrostomy site stricture occurred in 5 of 24 (~20%) of the operated cats at an average of 92 ± 25 days post-perineal urethrostomy. LUCi ranged from 6 to 10 (median 10) Fr and the LUCp ranged from 4 to 10 (median 8) Fr. There was a significant decrease of 0.15 ± 0.09 mm² of the urethral orifice cross-section area 12 days post-operative compared to the measurements taken immediately post-operative. The probabilities for post-operative urinary obstruction of the LUCi ≤ 8Fr cases (intra-operative urethral orifice cross-section area equal or larger than 5.5 mm² ) and in the LUCi > 8Fr cases were 44 and 6%, respectively. Recurrence of obstruction was documented in all cases (three cats) in which LUCi was 6Fr.

CONCLUSION AND CLINICAL SIGNIFICANCE

The largest size of the urinary catheter that is possible to insert during surgery is a simple method to evaluate urethrostomy cross-section size. Contraction of the urethral orifice diameter is expected during the wound healing phase. Post-operative urinary obstruction is more likely in cases where LUCi < 8Fr.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Five-year survival outcomes for patients with advanced melanoma treated with pembrolizumab in KEYNOTE-001

BACKGROUND

Pembrolizumab demonstrated robust antitumor activity and safety in the phase Ib KEYNOTE-001 study (NCT01295827) of advanced melanoma. Five-year outcomes in all patients and treatment-naive patients are reported herein. Patients whose disease progressed following initial response and who received a second course of pembrolizumab were also analyzed.

PATIENTS AND METHODS

Patients aged ≥18 years with previously treated or treatment-naive advanced/metastatic melanoma received pembrolizumab 2 mg/kg every 3 weeks, 10 mg/kg every 3 weeks, or 10 mg/kg every 2 weeks until disease progression, intolerable toxicity, or patient/investigator decision to withdraw. Kaplan-Meier estimates of overall survival (OS) and progression-free survival (PFS) were calculated. Objective response rate and PFS were based on immune-related response criteria by investigator assessment (data cut-off, September 1, 2017).

RESULTS

KEYNOTE-001 enrolled 655 patients with melanoma; median follow-up was 55 months. Estimated 5-year OS was 34% in all patients and 41% in treatment-naive patients; median OS was 23.8 months (95% CI, 20.2-30.4) and 38.6 months (95% CI, 27.2-not reached), respectively. Estimated 5-year PFS rates were 21% in all patients and 29% in treatment-naive patients; median PFS was 8.3 months (95% CI, 5.8-11.1) and 16.9 months (95% CI, 9.3-35.5), respectively. Median response duration was not reached; 73% of all responses and 82% of treatment-naive responses were ongoing at data cut-off; the longest response was ongoing at 66 months. Four patients [all with prior response of complete response (CR)] whose disease progressed during observation subsequently received second-course pembrolizumab. One patient each achieved CR and partial response (after data cut-off). Treatment-related AEs (TRAEs) occurred in 86% of patients and resulted in study discontinuation in 7.8%; 17% experienced grade 3/4 TRAE.

CONCLUSIONS

This 5-year analysis of KEYNOTE-001 represents the longest follow-up for pembrolizumab to date and confirms the durable antitumor activity and tolerability of pembrolizumab in advanced melanoma.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov, NCT01295827.

Minimally invasive technique for coxofemoral luxation stabilisation using transarticular toggle system: a cadaveric study

OBJECTIVE

To present a novel, semi-closed, surgical technique for coxofemoral luxation stabilisation using a transarticular toggle rod.

STUDY DESIGN

Cadaveric study.

MATERIALS AND METHODS

Craniodorsal luxation was generated by transecting the ligamentum teres in 12 coxofemoral joints and was then reduced using a closed technique. Anteversion and inclination angles were measured using fluoroscopic projections. An arthroscope was inserted through a bone tunnel drilled from the third trochanter through the femoral neck. Following retraction of the arthroscope, a hole was drilled through the acetabular fossa via the femoral bone tunnel. A standard Arthrex® TightRope toggle button was pushed through the femoral bone tunnel into the acetabular fossa hole and tied over the oval metallic button above the third trochanter site. The exit point of the drill hole over the femoral head and that in the acetabular fossa were evaluated by surgical exposure of the coxofemoral articular surfaces.

RESULTS

The TightRope entrance point into the acetabular fossa was accurate in all joints, with a mean distance from the acetabular fossa centre of 0·06 ±0·1 mm. The measured distance of the TightRope exit point from the femoral head to the fovea capitis was 2·04 ±1·7 mm. Femoral head cartilage damage was detected in nine of 12 joints.

CONCLUSION AND CLINICAL RELEVANCE

Closed reduction and stabilisation of coxofemoral luxations can be achieved using this minimally invasive technique. Refinements to the technique may be needed for its application in clinical cases due to relative high incidence of femoral head cartilage damage.

The taste response to ammonia in Drosophila

Ammonia is both a building block and a breakdown product of amino acids and is found widely in the environment. The odor of ammonia is attractive to many insects, including insect vectors of disease. The olfactory response of Drosophila to ammonia has been studied in some detail, but the taste response has received remarkably little attention. Here, we show that ammonia is a taste cue for Drosophila. Nearly all sensilla of the major taste organ of the Drosophila head house a neuron that responds to neutral solutions of ammonia. Ammonia is toxic at high levels to many organisms, and we find that it has a negative valence in two paradigms of taste behavior, one operating over hours and the other over seconds. Physiological and behavioral responses to ammonia depend at least in part on Gr66a+ bitter-sensing taste neurons, which activate a circuit that deters feeding. The Amt transporter, a critical component of olfactory responses to ammonia, is widely expressed in taste neurons but is not required for taste responses. This work establishes ammonia as an ecologically important taste cue in Drosophila, and shows that it can activate circuits that promote opposite behavioral outcomes via different sensory systems.

Downregulation of β-actin and its regulatory gene HuR affect cell migration of human corneal fibroblasts

PURPOSE

In an earlier study, we showed that human antigen R (HuR) and β-actin expression levels were downregulated in fibroblasts isolated from human keratoconus stroma compared to normal corneal stroma. To further extend the finding, we determined whether HuR expression affects β-actin gene expression and in turn affects corneal fibroblast migration and wound healing.

METHODS

Stromal keratocytes from normal human corneas were cultured in the presence of serum. Cells were transfected with siRNA specific for β-actin or HuR. SiRNAs specific for GAPDH or a scrambled sequence were used as positive and negative controls (siCTR) for transfection, respectively. The effects of gene silencing were analyzed at the transcriptional and translational levels. Specific proteins were immunohistochemically localized using confocal imaging. The effects of gene silencing on cell migration and cell proliferation were analyzed using a modified Boyden chamber and with a wound healing assay, respectively.

RESULTS

Reverse-transcription PCR (RT-PCR) and western blot analyses showed that when the HuR gene was silenced, β-actin expression was significantly downregulated. This was further confirmed at the translational level with immunohistochemical-confocal analysis. However, when the β-actin gene was silenced, its expression was significantly decreased but showed no effect on HuR gene expression. When the β-actin or HuR gene was individually silenced, the motility and proliferation of corneal fibroblasts were significantly reduced.

CONCLUSIONS

The results show that downregulation of the HuR gene results in decreased β-actin gene expression, which in turn results in decreased motility and proliferation of corneal fibroblasts. We conclude that decreased β-actin expression in normal corneal stroma clearly disrupts the cytoskeletal structure and functions, including keratocyte motility and wound healing.

Successful treatment of verruca vulgaris with Thuja occidentalis in a renal allograft recipient

Human papillomavirus-driven verruca vulgaris infection is common in solid organ transplant recipients and increases the risk for squamous cell carcinoma. The available treatment modalities have limited response. We report a renal allograft recipient who presented with multiple warts not responding to cryotherapy and radiosurgery with one turning malignant, needing amputation of the finger. An extract from Thuja occidentalis (White cedar tree) cured the resistant warts on the other fingers, leaving only superficial scars and without affecting allograft function. We have reviewed the pharmacological and clinical properties of T. occidentalis.