Impact of donor lung pathogenic bacteria on patient outcomes in the immediate post-transplant period

BACKGROUND

Patient outcomes post-lung transplant remain inferior to other types of solid organ transplantation. We investigated whether the presence of potentially pathogenic bacteria (PPB) in donor lung bronchial cultures was associated with adverse outcomes postoperatively.

METHODS

All patients who underwent lung transplantation between August 2015 and April 2017 at the University of Kentucky Medical Center were retrospectively reviewed. Retransplants, patients with bronchiectasis (including cystic fibrosis), and individuals who received organs from donation after cardiac death (DCD) donors were excluded. The remaining subjects were separated into two groups: individuals whose donor bronchial cultures grew PPB, and those whose cultures either returned negative for PPB or were sterile. 30-day mortality rates as well as the incidence of grade 3 primary graft dysfunction (PGD) and acute kidney injury (AKI) at both 24 and 72 hours post-transplant were calculated. The duration of mechanical ventilation postoperatively was also recorded.

RESULTS

Thirty two subjects comprised the study population. 20 patients (63%) had growth of PPB on donor cultures, while 12 (37%) did not. Patients with PPB had a significantly greater number of days on the ventilator postoperatively compared to those with no PPB (mean = 11.3 and median = 5.0 vs mean = 5.8 and median = 3.0, respectively, P = 0.0232). Subsequent regression analysis revealed this association to not be influenced by recipient lung allocation score (LAS), donor age, donor smoking history, recipient mean pulmonary artery pressure (mPAP) value, and/or use of cardiopulmonary bypass at the time of transplantation. Neither 30-day survival nor incidence of Grade 3 PGD and AKI at 24 or 72 hours post-transplant differed between the two groups (P > 0.05).

CONCLUSION

The recovery of PPB in donor lung cultures was associated with a longer duration of mechanical ventilation postoperatively in lung transplant recipients.

Feasibility of Ultrasound-Based Computational Fluid Dynamics as a Mitral Valve Regurgitation Quantification Technique: Comparison with 2-D and 3-D Proximal Isovelocity Surface Area-Based Methods

Current Doppler echocardiography quantification of mitral regurgitation (MR) severity has shortcomings. Proximal isovelocity surface area (PISA)-based methods, for example, are unable to account for the fact that ultrasound Doppler can measure only one velocity component: toward or away from the transducer. In the present study, we used ultrasound-based computational fluid dynamics (Ub-CFD) to quantify mitral regurgitation and study its advantages and disadvantages compared with 2-D and 3-D PISA methods. For Ub-CFD, patient-specific mitral valve geometry and velocity data were obtained from clinical ultrasound followed by 3-D CFD simulations at an assumed flow rate. We then obtained the average ratio of the ultrasound Doppler velocities to CFD velocities in the flow convergence region, and scaled CFD flow rate with this ratio as the final measured flow rate. We evaluated Ub-CFD, 2-D PISA and 3-D PISA with an in vitro flow loop, which featured regurgitation flow through (i) a simplified flat plate with round orifice and (ii) a 3-D printed realistic mitral valve and regurgitation orifice. The Ub-CFD and 3-D PISA methods had higher precision than the 2-D PISA method. Ub-CFD had consistent accuracy under all conditions tested, whereas 2-D PISA had the lowest overall accuracy. In vitro investigations indicated that the accuracy of 2-D and 3-D PISA depended significantly on the choice of aliasing velocity. Evaluation of these techniques was also performed for two clinical cases, and the dependency of PISA on aliasing velocity was similarly observed. Ub-CFD was robustly accurate and precise and has promise for future translation to clinical practice.

Biology and treatment of metastasis of sarcoma to the brain

Sarcomas are rare tumors with devastating clinical consequences, often affecting children as well as adults. Brain metastasis in sarcoma is frequently preceded by lung metastasis. Common offenders include Ewing sarcoma, osteosarcoma and leiomyosarcoma. Although our understanding of sarcoma metastasis remains limited, several cellular factors and signaling pathways appear to play regulatory roles and/or exhibit prognostic values in sarcoma metastasis. In addition, MicroRNAs have been shown to have either positive or negative impact on sarcoma biology and metastasis. Sarcoma is considered one of the classic radio- and chemo-resistant brain metastasis, hence the use of multiple modalities in order to improve the therapeutic ratio and overcome the inherent resistance. Treatment modalities include surgical resection, chemotherapy, gamma knife radiosurgery and/or fractionated whole-brain radiotherapy. The efficacy of chemotherapy is limited by the ability of the drug(s) to cross the blood-brain barrier (BBB), and the chemosensitivity of the tumor to the chemotherapeutic agent. In this review, we discuss the pathology, biology and therapy for sarcoma brain metastasis.

Creating pedestrian crash scenarios in a driving simulator environment

OBJECTIVE

In 2012 in the United States, pedestrian injuries accounted for 3.3% of all traffic injuries but, disproportionately, pedestrian fatalities accounted for roughly 14% of traffic-related deaths (NHTSA 2014 ). In many other countries, pedestrians make up more than 50% of those injured and killed in crashes. This research project examined driver response to crash-imminent situations involving pedestrians in a high-fidelity, full-motion driving simulator. This article presents a scenario development method and discusses experimental design and control issues in conducting pedestrian crash research in a simulation environment. Driving simulators offer a safe environment in which to test driver response and offer the advantage of having virtual pedestrian models that move realistically, unlike test track studies, which by nature must use pedestrian dummies on some moving track.

METHODS

An analysis of pedestrian crash trajectories, speeds, roadside features, and pedestrian behavior was used to create 18 unique crash scenarios representative of the most frequent and most costly crash types. For the study reported here, we only considered scenarios where the car is traveling straight because these represent the majority of fatalities. We manipulated driver expectation of a pedestrian both by presenting intersection and mid-block crossing as well as by using features in the scene to direct the driver's visual attention toward or away from the crossing pedestrian. Three visual environments for the scenarios were used to provide a variety of roadside environments and speed: a 20-30 mph residential area, a 55 mph rural undivided highway, and a 40 mph urban area.

RESULTS

Many variables of crash situations were considered in selecting and developing the scenarios, including vehicle and pedestrian movements; roadway and roadside features; environmental conditions; and characteristics of the pedestrian, driver, and vehicle. The driving simulator scenarios were subjected to iterative testing to adjust time to arrival triggers for the pedestrian actions. This article discusses the rationale behind creating the simulator scenarios and some of the procedural considerations for conducting this type of research.

CONCLUSIONS

Crash analyses can be used to construct test scenarios for driver behavior evaluations using driving simulators. By considering trajectories, roadway, and environmental conditions of real-world crashes, representative virtual scenarios can serve as safe test beds for advanced driver assistance systems. The results of such research can be used to inform pedestrian crash avoidance/mitigation systems by identifying driver error, driver response time, and driver response choice (i.e., steering vs. braking).

Assessment of point-of-care measurement of international normalised ratio using the CoaguChek XS Plus system in the setting of acute ischaemic stroke

BACKGROUND AND AIMS

Thrombolysis with alteplase (recombinant tissue plasminogen activator) is accepted hyperacute therapy for acute ischaemic stroke. Clotting must be normal before this can be administered safely. Laboratory testing of international normalised ratio (INR) takes 30-60 min, which can significantly delay administration of recombinant tissue plasminogen activator. Previous studies have suggested that point-of-care testing is useful in patients presenting with stroke and improves door-to-needle time. We performed a prospective study of point-of-care testing in patients presenting with acute ischaemic stroke.

METHODS

Fifty patients were entered into the study to compare point-of-care testing using the CoaguChek XS system with laboratory testing of INR.

RESULTS

Point-of-care testing correlated well with laboratory levels (R = 0.93, P < 0.0001). The standard deviation of difference between the two was 0.115. Overall, point-of-care testing tended to underestimate INR slightly, meaning that an INR value of 1.1 or less was required to be 95% certain that the laboratory value was 1.3 or below. Simultaneous testing using blood from a syringe was more consistent with laboratory results than testing capillary blood through finger prick.

CONCLUSION

Point-of-care INR testing correlates well with laboratory values. The results in this study mostly relate to values in the normal range. We suggest that it can be used to try to shorten door-to-needle time.

A survey of benthic assemblages of foraminifera in tropical coastal waters of pulau pinang, malaysia

The distribution of benthic Foraminifera throughout the coastal waters of Taman Negara Pulau Pinang (Penang National Park), Malaysia was studied to assess the impact of various anthropogenic activities, such as fishing, ecotourism and floating cage culture. Samples were obtained at 200 m intervals within the subtidal zone, extending up to 1200 m offshore at Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh. The depth within coastal waters ranged between 1.5 m and 10.0 m, with predominantly muddy substrate at most stations. Water quality analysis showed little variation in micronutrient (nitrite, NO2; nitrate, NO3; ammonia, NH4 and orthophosphate, PO4) concentrations between sampling stations. Temperature (29.6±0.48°C), salinity (29.4±0.28 ppt), dissolved oxygen content (5.4±0.95 mg/l) and pH (8.5± 0.13) also showed little fluctuation between stations. A total of nine genera of foraminifera were identified in the study (i.e., Ammonia, Elphidium, Ammobaculites, Bigenerina, Quinqueloculina, Reopax, Globigerina, Textularia and Nonion). The distribution of benthic foraminifera was dominated by opportunistic groups that have a high tolerance to anthropogenic stressors. Ammonia had the highest frequency of occurrence (84.7%), followed by Bigenerina (50%), Ammobaculites (44.2%) and Elphidium (38.9%). The Ammonia-Elphidium Index (AEI) was used to describe the hypoxic condition of benthic communities at all sites. Teluk Bahang had the highest AEI value. The foraminiferal assemblages and distribution in Teluk Bahang, Teluk Aling, Teluk Ketapang and Pantai Acheh showed no correlation with physical or chemical environmental parameters.

Sudden suffocation with cancer of unknown primary: a case report and review of diagnostic approach

A case of a 31-year-old woman with sudden respiratory distress is presented. Preliminary evaluations and imaging studies did not reveal the underlying cause. Workup during hospital stay showed advanced metastatic cancer of unknown primary origin. This is an unusual presentation of cancer of an unknown primary involving the thyroid with sudden suffocation. It suggests that malignancies involving the thyroid gland should be considered in patients with abrupt onset of respiratory distress. Also, this case shows the application of fine needle aspiration in diffuse thyroid enlargements mimicking thyroiditis without nodules. Diagnostic approach to cancer of unknown primary origin (CUP) is reviewed in further detail.

An in vivo comparison of hip structure analysis (HSA) with measurements obtained by QCT

SUMMARY

In a population of elderly women, bone cross-sectional area (CSA), cross-sectional moment of inertia (CSMI), section modulus (Z), femoral neck axis length (FNAL), and width measured with hip structure analysis (HSA) on dual-energy x-ray absorptiometry (DXA) images in the femoral neck and trochanteric regions are highly correlated to quantitative computed tomography (QCT) measurements.

INTRODUCTION

HSA is a method of obtaining measurements of proximal femur structure using 2D DXA technology. This study was designed to examine the correlations between HSA measurements and 3D QCT.

METHODS

Forty-one women (mean age, 82.8 ± 2.5 years) were measured using DXA and a 64-slice CT scanner (1 mm slice thickness, 0.29 mm in plane resolution). HSA parameters were calculated at the narrow neck (NN) and trochanteric (IT) regions on the DXA image. These regions were then translated to anatomically equivalent regions on the QCT dataset by co-registering the DXA image and QCT dataset using four DXA images acquired at different angles.

RESULTS

At the NN and IT regions, high linear correlations were measured between HSA and QCT for CSA r = 0.95 and 0.93, CSMI r = 0.94 and 0.93, and Z r = 0.93 and 0.89, respectively. All correlations were highly significant (p < 0.001), but there were differences in slope and offset between the two techniques, at least in part due to differences in calibration between the two techniques. FNAL and width of the bone at the NN and IT regions, physical measurements independent of the calibration, were highly correlated (r = 0.90-0.95, p < 0.001) and had slopes close to 1.0 (range, 0.978 to 1.003).

CONCLUSION

CSA, CSMI, Z, FNAL, and width measured by HSA correlate highly to high-resolution QCT.

Volumetric DXA (VXA): A new method to extract 3D information from multiple in vivo DXA images

Three-dimensional geometric and structural measurements of the proximal femur are of considerable interest in understanding the strength of the femur and its susceptibility to fracture. Quantitative computed tomography (QCT) with a small voxel size (≤1 mm per side) is the current "gold standard" to examine the macrostructure of the femur, but it has a high effective radiation dose (approximately 2 to 5 mSv) and cost. Volumetric dual-energy X-ray absorptiometry (VXA) uses a commercially available DXA system (Hologic Discovery A) to reconstruct the proximal femur from four DXA scans delivering an effective radiation dose of 0.04 mSv. VXA was compared with QCT (voxel size of 0.29 × 0.29 × 1 mm) in 41 elderly women (age 82 ± 2.4 years) at slices located at the femoral neck and trochanteric regions of interest. For parameters of shape, the femoral neck axis length (FNAL) and the cross-sectional slice area (SA), accuracy and strong linear correlations (r = 0.84 to 0.98) were demonstrated. Similar correlations (r = 0.81 to 0.97) were observed for the density parameters, the cross-sectional bone area (CSA) and volumetric bone mineral density (vBMD). VXA also demonstrated strong correlations (r = 0.76 to 0.99) for the engineering parameters of the minimum, maximum, and polar cross-sectional moments of inertia (CSMIs) and the section modulus (Z). We conclude that VXA is capable of generating a variety of 3D geometric and structural measurements that are highly correlated with QCT in elderly subjects in vivo. Moreover, the VXA measurements can be made with a commercially available DXA device at a very low radiation dose.

Rhabdoid meningioma presenting with subependymal and diffuse meningeal involvement but no mass lesion

Rhabdoid meningiomas are rare, aggressive tumours of the meninges that have a generally poor prognosis. We report a 49-year-old man with a background history of sarcoidosis who presented with nausea and vomiting. Imaging showed generalised leptomeningeal and subependymal enhancement suggestive of chronic meningitis. He had multiple lumbar punctures and a brain biopsy, none of which led to a pathological diagnosis. He died within months, and a postmortem examination was performed. At this stage, a diagnosis of rhabdoid meningioma was made. The clinical and radiological presentation of rhabdoid meningioma as a diffuse leptomeningeal process without a mass lesion is unique. All other published cases of rhabdoid meningioma have been of a discrete lesion. This highlights the importance of a tissue diagnosis in patients where the imaging is non-specific. A brief review of rhabdoid meningioma follows.

Atrial fibrillation and anticoagulation in a stroke unit population

BACKGROUND

Atrial fibrillation (AF) is an important predisposing factor for ischaemic stroke. There is evidence to suggest that even in appropriate candidates warfarin therapy is underutilized. We assessed the prevalence of AF in an Australian stroke unit to determine the degree of undertreatment at presentation.

METHODS

A retrospective analysis of all patients admitted to our Stroke Unit between October 2004 and September 2006 was carried out. All patients with a diagnosis of AF, either new or old, were then selected from this group to determine the overall prevalence and anticoagulation status. Data regarding prior stroke, stroke severity and discharge anticoagulation status were also determined.

RESULTS

Data from a total of 500 patients were analysed. Our results showed that AF-related strokes accounted for a large proportion (28%) of all admissions and were associated with a larger neurological deficit. Most patients (68%) with a prior diagnosis of AF without having obvious contraindications were either not anticoagulated or under-anticoagulated when presenting with an ischaemic stroke or transient ischaemic attack.

CONCLUSION

Our results stress the importance of initiating and maintaining anticoagulation in patients with AF and without obvious contraindications to minimize the risk of subsequent stroke.

Echocardiography in the detection of cardioembolism in a stroke population

Both transthoracic (TTE) and transoesophageal (TOE) echocardiography are used routinely to investigate ischaemic stroke. We retrospectively assessed the incidence of abnormalities on TTE/TOE and whether an abnormal TTE/TOE result could have been predicted on the basis of ancillary tests and clinical cardiological examination. Data from 428 patients were analysed. The diagnostic yield of TTE was 12%. For TOE there was a diagnostic yield of 40% in tests actually performed. Overall, echocardiography altered management in 5% of patients. A significant correlation was found between clinical cardiac disease, stroke subtype and the diagnostic yield of TTE. We conclude that the vast majority of abnormal findings occur in patients who already have clinical evidence of cardiac disease. This suggests that the use of these tests should not be "routine", but determined on an individual patient basis.

The photoreceptor-specific nuclear receptor Nr2e3 interacts with Crx and exerts opposing effects on the transcription of rod versus cone genes

Nr2e3 is an orphan nuclear receptor expressed specifically by retinal photoreceptor cells. Mutations in Nr2e3 result in syndromes characterized by excess blue cones and loss of rods: enhanced S-cone syndrome (ESCS) in humans and rd7 in mice. Using yeast two-hybrid screens with Nr2e3 as bait, the cone-rod homeobox protein Crx was identified as an interacting partner of Nr2e3. Immunoprecipitation assays confirmed this Nr2e3-Crx interaction and identified the DNA-binding domain of each protein as the interaction motif. Immunohistochemistry demonstrated that Crx and Nr2e3 are co-expressed by rod photoreceptors and their precursors. Chromatin immunoprecipitation assays on mouse retina demonstrated that Nr2e3 and Crx co-occupy the promoter/enhancer region of several rod and cone genes in the rod photoreceptor cells. The promoter/enhancer occupancy of Nr2e3 is Crx-dependent, suggesting that Nr2e3 is associated with photoreceptor gene targets by interacting with Crx. Transient transfection assays in HEK293 cells demonstrated that Nr2e3 enhances rhodopsin, but represses S- or M-cone opsin transcription when interacting with Crx. Quantitative real-time RT-PCR analysis on postnatal day 28 (P28) retina of the rd7 mouse, which lacks Nr2e3 protein, revealed an up-regulation of cone genes, but down-regulation of rod genes. Several mutant forms of human Nr2e3 identified from ESCS patients showed defects in interacting with Crx and/or in transcriptional regulatory function. Altogether, our findings suggest that Nr2e3 is a dual-function transcriptional regulator that acts in concert with Crx to promote and maintain the function of rod photoreceptors.