Coronary Artery Disease and Coronary Artery Bypass Grafting at the Time of Lung Transplantation Do Not Impact Overall Survival.

BACKGROUND: Coronary artery disease (CAD) is common in lung transplant candidates and may require revascularization before or at the time of their transplant. We reviewed the survival of lung transplant recipients with CAD requiring surgical intervention (CAD-coronary artery bypass grafting [CABG]) and those who did not (CAD-NoCABG) at the time of transplant, compared to a cohort with no CAD (NoCAD). METHODS: We conducted a retrospective cohort study of adult patients transplanted in our program between 2004 and 2013. Our primary outcome was the association between 3-way CAD status (CAD-CABG, CAD-NoCABG, NoCAD) and overall retransplant-free survival via proportional hazards modeling, adjusting for age, gender, and transplant indication. Secondary endpoints included 1-year survival, survival by Kaplan-Meier analysis, duration of ventilation, intensive care unit stay, and hospitalization. RESULTS: A total of 333 patients underwent transplant during the study timeframe. A total of 24 (7%) had CAD requiring CABG, 82 (25%) had CAD not requiring CABG, and the remaining 227 had no CAD. The 3-way CAD status was not associated with overall retransplant-free survival after adjustment for age, gender, and transplant indication. Duration of mechanical ventilation, intensive care unit stay and hospitalization were longer in both CAD groups compared with the NoCAD group. CONCLUSIONS: CAD status does not impact overall retransplant-free survival, despite greater perioperative complexity. Prospective studies comparing treatment strategies in these patient groups are warranted.

Baseline lung allograft dysfunction is associated with impaired survival after double-lung transplantation.

BACKGROUND: The prognostic value of defining normal vs abnormal baseline post-transplant lung function (or baseline lung allograft dysfunction [BLAD]) has not been studied using standardized reference values of percent predicted of the population. Our aim was to assess the association between BLAD and survival in double-lung transplant recipients and assess for potential pre-transplant donor and recipient risk factors for BLAD. METHODS: We conducted a retrospective cohort study of double-lung transplant recipients in our program during the period 2004 to 2009. We defined normal baseline function as both forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) ≥80% predicted on at least 2 consecutive tests ≥3 weeks apart; we defined BLAD as failure to meet these criteria. We used a Cox regression model to assess the association between BLAD and survival. We used logistic regression to assess potential pre-transplant donor and recipient factors associated with BLAD. RESULTS: Of 178 patients double-lung transplant recipients eligible for study, 75 (42%) met the criteria for BLAD. BLAD was associated with impaired survival (hazard ratio [HR] 2.23, 95% confidence interval [CI] 1.41 to 3.54]) via Cox regression compared to patients with normal baseline, and lower baseline was associated with greater risk of death in a dose-dependent fashion. Pre-transplant factors associated with BLAD included interstitial lung disease (ILD) as an indication for transplant (odds ratio [OR] 2.66, 95% CI 1.17 to 6.15) and heavy donor smoking history (OR 3.07, 95% CI 1.17 to 8.43). CONCLUSIONS: BLAD is dynamic risk state associated with impaired survival after double-lung transplantation, and should be considered when physiologically phenotyping patients.

Environmental RNAi in herbivorous insects.

Environmental RNAi (eRNAi) is a sequence-specific regulation of endogenous gene expression in a receptive organism by exogenous double-stranded RNA (dsRNA). Although demonstrated under artificial dietary conditions and via transgenic plant presentations in several herbivorous insects, the magnitude and consequence of exogenous dsRNA uptake and the role of eRNAi remains unknown under natural insect living conditions. Our analysis of coleopteran insects sensitive to eRNAi fed on wild-type plants revealed uptake of plant endogenous long dsRNAs, but not small RNAs. Subsequently, the dsRNAs were processed into 21 nt siRNAs by insects and accumulated in high quantities in insect cells. No accumulation of host plant-derived siRNAs was observed in lepidopteran larvae that are recalcitrant to eRNAi. Stability of ingested dsRNA in coleopteran larval gut followed by uptake and transport from the gut to distal tissues appeared to be enabling factors for eRNAi. Although a relatively large number of distinct coleopteran insect-processed plant-derived siRNAs had sequence complementarity to insect transcripts, the vast majority of the siRNAs were present in relatively low abundance, and RNA-seq analysis did not detect a significant effect of plant-derived siRNAs on insect transcriptome. In summary, we observed a broad genome-wide uptake of plant endogenous dsRNA and subsequent processing of ingested dsRNA into 21 nt siRNAs in eRNAi-sensitive insects under natural feeding conditions. In addition to dsRNA stability in gut lumen and uptake, dosage of siRNAs targeting a given insect transcript is likely an important factor in order to achieve measurable eRNAi-based regulation in eRNAi-competent insects that lack an apparent silencing amplification mechanism.

Ablation of Dental Hard Tissues with a Microsecond Pulsed Carbon Dioxide Laser Operating at 9.3-µm with an Integrated Scanner.

Pulsed carbon dioxide lasers operating at the highly absorbed 9.3 and 9.6-µm wavelengths with pulse durations in the microsecond range are ideally suited for dental hard tissue modification and removal. The purpose of these studies was to demonstrate that a low cost 9.3-µm CO(2) laser system utilizing low-energy laser pulses (1-5 mJ /pulse) delivered at a high repetition rate (400-Hz) is feasible for removing dental hard tissues. The laser beam was focused to a small spot size to achieve ablative fluence and an integrated/programmable optical scanner was used to scan the laser beam over the desired area for tissue removal. Pulse durations of 35, 60 and 75-µs were employed and the enamel and dentin ablation rate and ablation efficiency were measured. Laser irradiated human and bovine samples were assessed for peripheral thermal and mechanical damage using polarized light microscopy. The heat accumulation during rapid scanning ablation with water-cooling at 400-Hz was monitored using micro-thermocouples. The laser was able to ablate both enamel and dentin without excessive peripheral thermal damage or heat accumulation. These preliminary studies suggest that a low-cost RF excited CO(2) laser used in conjunction with an integrated scanner has considerable potential for application to dental hard tissues.

Biomechanical analysis of occupant kinematics in rollover motor vehicle accidents: dynamic spit test.

A better understanding of occupant kinematics in rollover accidents helps to advance biomechanical knowledge and to enhance the safety features of motor vehicles. While many rollover accident simulation studies have adopted the static approach to delineate the occupant kinematics in rollover accidents, very few studies have attempted the dynamic approach. The present work was designed to study the biomechanics of restrained occupants during rollover accidents using the steady-state dynamic spit test and to address the importance of keeping the lap belt fastened. Experimental tests were conducted using an anthropometric 50% Hybrid III dummy in a vehicle. The vehicle was rotated at 180 degrees/second and the dummy was restrained using a standard three-point restraint system. The lap belt of the dummy was fastened either by using the cinching latch plate or by locking the retractor. Three configurations of shoulder belt harness were simulated: shoulder belt loose on chest with cinch plate, shoulder belt under the left arm and shoulder belt behind the chest. In all tests, the dummy stayed within the confinement of the vehicle indicating that the securely fastened lap belt holds the dummy with dynamic movement of 3 1/2" to 4". The results show that occupant movement in rollover accidents is least affected by various shoulder harness positions with a securely fastened lap belt. The present study forms a first step in delineating the biomechanics of occupants in rollover accidents.

Biomechanics of seat belt restraint system.

Seat belt system restrains and protects occupants in motor vehicle crashes and any slack in seat belt system induces additional loading on occupant. Signs of belt loading are more obvious in high-speed frontal collisions with heavy occupants. However subtle changes may occur at low speeds or with low forces from occupants during rollovers. In certain cases, the seat belt webbing is twisted and loaded by the occupant. The loading of webbing induces an observable fold/crimp on the seat belt. The purpose of the study is to biomechanically evaluate the force required to produce such marks using an anthropometric physical test dummy. Two tests were conducted to determine the amount of force required to put an observable fold/crimp in a shoulder belt. A head form designed by Voight Hodgson was used to represent the neck which interacted with the belt. The force was applied with a pneumatic pull ram (central hydraulic 89182 N) and the force was measured with a 44,000 N transducer load cell (DSM-10K). Results indicate that the force of over 1,000 N produced a fold or crimp in the belt.

Biomechanical injury evaluation of laminated side door windows and sunroof during rollover accidents.

Significantly more fatalities and serious injuries occur due to ejection in roll over accidents. The present study was conducted to determine the occupant retention and head-neck injury potential aspects of laminated glass in side door windows and sunroofs during roll over accidents. The test protocol for this study was based on National Highway Traffic Safety Administration (NHTSA) studies for advanced glazing. The impact study of 18 kg with head-neck form was conducted on laminated glass of side doors and sunroofs from production vehicles. The drop speed was varied from 11 to 16 kph. The Hybrid III 50% male dummy head-neck form was impacted on the approximately center of the glass portion of the windows. The head injury criteria, head resultant acceleration, and neck loads and moments were quantified. A series of drop tests were conducted on roll down side windows with laminated glass. The head-neck biomechanical parameters were well below the critical value injury tolerance limits. Results indicated that the glass contained the dummy assembly and the head-neck biomechanical parameters were below the critical value injury tolerance limits in simulated rollover accidents. The present study demonstrates that head-neck injury is unlikely due to laminated glass side windows and sunroof laminated glass used in production vehicles during rollover accidents and that the dummy is contained by the laminated glazing.

Inverted drop testing and neck injury potential.

Inverted drop testing of vehicles is a methodology that has long been used by the automotive industry and researchers to test roof integrity and is currently being considered by the National Highway Traffic Safety Administration as a roof strength test. In 1990 a study was reported which involved 8 dolly rollover tests and 5 inverted drop tests. These studies were conducted with restrained Hybrid III instrumented Anthropometric Test Devices (ATD) in production and rollcaged vehicles to investigate the relationship between roof strength and occupant injury potential. The 5 inverted drop tests included in the study provided a methodology producing "repeatable roof impacts" exposing the ATDs to the similar impact environment as those seen in the dolly rollover tests. Authors have conducted two inverted drop test sets as part of an investigation of two real world rollover accidents. Hybrid-III ATD's were used in each test with instrumented head and necks. Both test sets confirm that reduction of roof intrusion and increased headroom can significantly enhance occupant protection. In both test pairs, the neck force of the dummy in the vehicle with less crush and more survival space was significantly lower. Reduced roof crush and dynamic preservation of the occupant survival space resulted in only minor occupant contact and minimal occupant loading, establishing a clear causal relationship between roof crush and neck injuries.