Genome-wide CRISPR screening identifies a role for ARRDC3 in TRP53-mediated responses.

Whole-genome screens using CRISPR technologies are powerful tools to identify novel tumour suppressors as well as factors that impact responses of malignant cells to anti-cancer agents. Applying this methodology to lymphoma cells, we conducted a genome-wide screen to identify novel inhibitors of tumour expansion that are induced by the tumour suppressor TRP53. We discovered that the absence of Arrestin domain containing 3 (ARRDC3) increases the survival and long-term competitiveness of MYC-driven lymphoma cells when treated with anti-cancer agents that activate TRP53. Deleting Arrdc3 in mice caused perinatal lethality due to various developmental abnormalities, including cardiac defects. Notably, the absence of ARRDC3 markedly accelerated MYC-driven lymphoma development. Thus, ARRDC3 is a new mediator of TRP53-mediated suppression of tumour expansion, and this discovery may open new avenues to harness this process for cancer therapy.

NCCN Guidelines® Insights: Head and Neck Cancers, Version 1.2022.

The NCCN Guidelines for Head and Neck Cancers address tumors arising in the oral cavity (including mucosal lip), pharynx, larynx, and paranasal sinuses. Occult primary cancer, salivary gland cancer, and mucosal melanoma (MM) are also addressed. The specific site of disease, stage, and pathologic findings guide treatment (eg, the appropriate surgical procedure, radiation targets, dose and fractionation of radiation, indications for systemic therapy). The NCCN Head and Neck Cancers Panel meets at least annually to review comments from reviewers within their institutions, examine relevant new data from publications and abstracts, and reevaluate and update their recommendations. These NCCN Guidelines Insights summarize the panel's most recent recommendations regarding management of HPV-positive oropharynx cancer and ongoing research in this area.

Effect of skin optical absorption on speckleplethysmographic (SPG) signals.

Recent advances in optical technology have emerged for measuring blood flow in the extremities using speckleplethysmography (SPG), which may address needs in vascular medicine and other fields. SPG has demonstrated a highly linear response with flow rate, but the susceptibility to differences in skin tone is unclear. Two validation studies using skin-simulating phantoms and a simple clinical protocol were conducted to determine the impact of absorbing skin layers on SPG measurements. Benchtop results demonstrated that the coefficient of determination between known flow rate and SPG was highly linear (R2 = 0.990) and was unaffected by the addition of skin-phantom layers with variable absorption (R2 = 0.996-0.999). Additionally, no significant trend was found between the fit residuals of SPG and flow rate with increasing skin-phantom absorption (R2=0.025, p = 0.29). In clinical testing, no significant difference was found using both a 4-way ANOVA between demographic classifications (F = 0.89, p = 0.45), and a 2-way ANOVA test between lower- and higher-melanin subclassifications (F = 0.4, p = 0.52).

Tuning the deformation mechanisms of boron carbide via silicon doping.

Boron carbide suffers from a loss of strength and toughness when subjected to high shear stresses due to amorphization. Here, we report that a small amount of Si doping (~1 atomic %) leads to a substantial decrease in stress-induced amorphization due to a noticeable change of the deformation mechanisms in boron carbide. In the undoped boron carbide, the Berkovich indentation-induced quasi-plasticity is dominated by amorphization and microcracking along the amorphous shear bands. This mechanism resulted in long, distinct, and single-variant shear faults. In contrast, substantial fragmentation with limited amorphization was activated in the Si-doped boron carbide, manifested by the short, diffuse, and multivariant shear faults. Microcracking via fragmentation competed with and subsequently mitigated amorphization. This work highlights the important roles that solute atoms play on the structural stability of boron carbide and opens up new avenues to tune deformation mechanisms of ceramics via doping.

Wearable speckle plethysmography (SPG) for characterizing microvascular flow and resistance.

In this work we introduce a modified form of laser speckle imaging (LSI) referred to as affixed transmission speckle analysis (ATSA) that uses a single coherent light source to probe two physiological signals: one related to pulsatile vascular expansion (classically known as the photoplethysmographic (PPG) waveform) and one related to pulsatile vascular blood flow (named here the speckle plethysmographic (SPG) waveform). The PPG signal is determined by recording intensity fluctuations, and the SPG signal is determined via the LSI dynamic light scattering technique. These two co-registered signals are obtained by transilluminating a single digit (e.g. finger) which produces quasi-periodic waveforms derived from the cardiac cycle. Because PPG and SPG waveforms probe vascular expansion and flow, respectively, in cm-thick tissue, these complementary phenomena are offset in time and have rich dynamic features. We characterize the timing offset and harmonic content of the waveforms in 16 human subjects and demonstrate physiologic relevance for assessing microvascular flow and resistance.

Correcting for motion artifact in handheld laser speckle images.

Laser speckle imaging (LSI) is a wide-field optical technique that enables superficial blood flow quantification. LSI is normally performed in a mounted configuration to decrease the likelihood of motion artifact. However, mounted LSI systems are cumbersome and difficult to transport quickly in a clinical setting for which portability is essential in providing bedside patient care. To address this issue, we created a handheld LSI device using scientific grade components. To account for motion artifact of the LSI device used in a handheld setup, we incorporated a fiducial marker (FM) into our imaging protocol and determined the difference between highest and lowest speckle contrast values for the FM within each data set (Kbest and Kworst). The difference between Kbest and Kworst in mounted and handheld setups was 8% and 52%, respectively, thereby reinforcing the need for motion artifact quantification. When using a threshold FM speckle contrast value (KFM) to identify a subset of images with an acceptable level of motion artifact, mounted and handheld LSI measurements of speckle contrast of a flow region (KFLOW) in in vitro flow phantom experiments differed by 8%. Without the use of the FM, mounted and handheld KFLOW values differed by 20%. To further validate our handheld LSI device, we compared mounted and handheld data from an in vivo porcine burn model of superficial and full thickness burns. The speckle contrast within the burn region (KBURN) of the mounted and handheld LSI data differed by <4 % when accounting for motion artifact using the FM, which is less than the speckle contrast difference between superficial and full thickness burns. Collectively, our results suggest the potential of handheld LSI with an FM as a suitable alternative to mounted LSI, especially in challenging clinical settings with space limitations such as the intensive care unit.

Design and evaluation of a miniature laser speckle imaging device to assess gingival health.

Current methods used to assess gingivitis are qualitative and subjective. We hypothesized that gingival perfusion measurements could provide a quantitative metric of disease severity. We constructed a compact laser speckle imaging (LSI) system that could be mounted in custom-made oral molds. Rigid fixation of the LSI system in the oral cavity enabled measurement of blood flow in the gingiva. In vitro validation performed in controlled flow phantoms demonstrated that the compact LSI system had comparable accuracy and linearity compared to a conventional bench-top LSI setup. In vivo validation demonstrated that the compact LSI system was capable of measuring expected blood flow dynamics during a standard postocclusive reactive hyperemia and that the compact LSI system could be used to measure gingival blood flow repeatedly without significant variation in measured blood flow values (p<0.05). Finally, compact LSI system measurements were collected from the interdental papilla of nine subjects and compared to a clinical assessment of gingival bleeding on probing. A statistically significant correlation (?=0.53; p<0.005) was found between these variables, indicating that quantitative gingival perfusion measurements performed using our system may aid in the diagnosis and prognosis of periodontal disease.

Land use and traffic collisions: A link-attribute analysis using Empirical Bayes method.

Road traffic collisions represent one of the major public health problems among the leading causes of deaths globally. This paper examines several approaches in detecting hazardous road locations, and discusses the spatial distribution of these locations as well as their relationships with different land uses in Hong Kong. Two most commonly used methodologies in detecting hazardous road locations are used: the hot spot and hot zone methodologies. Both methodologies are performed using raw collision count, excess collision count and Empirical Bayes (EB) estimations. The EB estimation uses land use characteristics near the road network in defining the reference groups. Finally all the approaches are compared by a test to assess their stability. The results show that for different hazardous road location detection methodologies, the best fit estimation methods on sites are different. The results confirm some land use impacts in previous studies, and suggest some further patterns on road safety. The findings are useful in understanding the complex interrelationships between land use and road safety, and in facilitating planners and policy makers to build safer cities.

The Role of Laser Speckle Imaging in Port-Wine Stain Research: Recent Advances and Opportunities.

Here, we review our current knowledge on the etiology and treatment of port-wine stain (PWS) birthmarks. Current treatment options have significant limitations in terms of efficacy. With the combination of 1) a suitable preclinical microvascular model, 2) laser speckle imaging (LSI) to evaluate blood-flow dynamics, and 3) a longitudinal experimental design, rapid preclinical assessment of new phototherapies can be translated from the lab to the clinic. The combination of photodynamic therapy (PDT) and pulsed-dye laser (PDL) irradiation achieves a synergistic effect that reduces the required radiant exposures of the individual phototherapies to achieve persistent vascular shutdown. PDL combined with anti-angiogenic agents is a promising strategy to achieve persistent vascular shutdown by preventing reformation and reperfusion of photocoagulated blood vessels. Integration of LSI into the clinical workflow may lead to surgical image guidance that maximizes acute photocoagulation, is expected to improve PWS therapeutic outcome. Continued integration of noninvasive optical imaging technologies and biochemical analysis collectively are expected to lead to more robust treatment strategies.

Utility of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) to non-invasively diagnose burn depth in a porcine model.

Surgical intervention of second degree burns is often delayed because of the difficulty in visual diagnosis, which increases the risk of scarring and infection. Non-invasive metrics have shown promise in accurately assessing burn depth. Here, we examine the use of spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) for predicting burn depth. Contact burn wounds of increasing severity were created on the dorsum of a Yorkshire pig, and wounds were imaged with SFDI/LSI starting immediately after-burn and then daily for the next 4 days. In addition, on each day the burn wounds were biopsied for histological analysis of burn depth, defined by collagen coagulation, apoptosis, and adnexal/vascular necrosis. Histological results show that collagen coagulation progressed from day 0 to day 1, and then stabilized. Results of burn wound imaging using non-invasive techniques were able to produce metrics that correlate to different predictors of burn depth. Collagen coagulation and apoptosis correlated with SFDI scattering coefficient parameter [Formula: see text] and adnexal/vascular necrosis on the day of burn correlated with blood flow determined by LSI. Therefore, incorporation of SFDI scattering coefficient and blood flow determined by LSI may provide an algorithm for accurate assessment of the severity of burn wounds in real time.

Fiber-based laser speckle imaging for the detection of pulsatile flow.

BACKGROUND AND OBJECTIVE: In endodontics, a major diagnostic challenge is the accurate assessment of pulp status. In this study, we designed and characterized a fiber-based laser speckle imaging system to study pulsatile blood flow in the tooth. STUDY DESIGN/MATERIALS AND METHODS: To take transilluminated laser speckle images of the teeth, we built a custom fiber-based probe. To assess our ability to detect changes in pulsatile flow, we performed in vitro and preliminary in vivo tests on tissue-simulating phantoms and human teeth. We imaged flow of intralipid in a glass microchannel at simulated heart rates ranging from 40 beats/minute (bpm) to 120 bpm (0.67-2.00 Hz). We also collected in vivo data from the upper front incisors of healthy subjects. From the measured raw speckle data, we calculated temporal speckle contrast versus time. With frequency-domain analysis, we identified the frequency components of the contrast waveforms. RESULTS: With our approach, we observed in vitro the presence of pulsatile flow at different simulated heart rates. We characterized simulated heart rate with an accuracy of and >98%. In the in vivo proof-of-principle experiment, we measured heart rates of 69, 90, and 57 bpm, which agreed with measurements of subject heart rate taken with a wearable, commercial pulse oximeter. CONCLUSIONS: We designed, built, and tested the performance of a dental imaging probe. Data from in vitro and in -vivo tests strongly suggest that this probe can detect the presence of pulsatile flow. LSI may enable endodontists to noninvasively assess pulpal vitality via direct measurement of blood flow.

Intraoperative, real-time monitoring of blood flow dynamics associated with laser surgery of port wine stain birthmarks.

BACKGROUND AND OBJECTIVE: Port-wine stain (PWS) birthmarks affect ∼22 million people worldwide. After several treatment sessions, complete disappearance of the PWS occurs in only ∼10% of treated patients. There is a need to develop a new strategy to improve the efficacy of each treatment session and the overall treatment outcome. The study objective was to determine how intraoperative measurements of blood flow correlate with treatment response assessed several weeks post treatment. STUDY DESIGN/MATERIALS AND METHODS: We employed Laser Speckle Imaging (LSI) to measure intraoperative blood-flow dynamics. We collected data from 24 subjects undergoing laser therapy for facial PWS birthmarks. Photographs were taken before treatment and at a follow-up visit, and analyzed by two expert observers. RESULTS: Intraoperative LSI enables real-time monitoring of blood-flow dynamics in response to laser treatment and can inform clinicians on the need for focused re-treatment. The degree of PWS blanching achieved is positively correlated with the log-transformed acute blood-flow reduction (P = 0.022). CONCLUSION: LSI is a simple, intraoperative monitoring tool during laser therapy of PWS birthmarks. LSI provides a single value for blood flow that correlates well with the degree of blanching achieved with laser therapy.

Quantitative assessment of graded burn wounds in a porcine model using spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI).

Accurate and timely assessment of burn wound severity is a critical component of wound management and has implications related to course of treatment. While most superficial burns and full thickness burns are easily diagnosed through visual inspection, burns that fall between these extremes are challenging to classify based on clinical appearance. Because of this, appropriate burn management may be delayed, increasing the risk of scarring and infection. Here we present an investigation that employs spatial frequency domain imaging (SFDI) and laser speckle imaging (LSI) as non-invasive technologies to characterize in-vivo burn severity. We used SFDI and LSI to investigate controlled burn wounds of graded severity in a Yorkshire pig model. Burn wounds were imaged starting at one hour after the initial injury and daily at approximately 24, 48 and 72 hours post burn. Biopsies were taken on each day in order to correlate the imaging data to the extent of burn damage as indicated via histological analysis. Changes in reduced scattering coefficient and blood flow could be used to categorize burn severity as soon as one hour after the burn injury. The results of this study suggest that SFDI and LSI information have the potential to provide useful metrics for quantifying the extent and severity of burn injuries.

Anterior shoulder dislocation increases the propensity for recurrence: a cadaveric study of the number of dislocations and type of capsulolabral lesion.

BACKGROUND: The number of anterior shoulder dislocations that predispose to recurrence is unknown; some clinicians recommend surgical repair after the initial episode and others after multiple recurrences. The purpose of this study was to quantify the forces during successive anterior dislocations of cadaveric shoulders and to inspect the capsule and labrum afterwards, in order to assess the propensity for recurrence. MATERIALS AND METHODS: Twenty-two human cadaveric shoulders were tested using a custom cadaveric shoulder dislocation device with simulated muscle loading. Each was positioned in the apprehension position and the humerus was moved in horizontal abduction until the shoulder dislocated. The joint reaction force was measured, as was the force that developed passively in the pectoralis major muscle. Following 3 successive dislocations, each was inspected for anterior capsulolabral lesions. RESULTS: There was a significant decrease in force after the second dislocation. In 11, there was no labral avulsion and a significant decrease in force after the first dislocation. In the other 11, there was a labral avulsion and a significant decrease in force after the second dislocation. CONCLUSION: Two successive anterior shoulder dislocations may increase propensity for recurrence; but this is influenced by the type of capsulolabral lesion that occurs. No labral avulsion, likely a result of capsular stretching, may be a worse prognostic finding than labral avulsion after the initial episode.

An overview of three promising mechanical, optical, and biochemical engineering approaches to improve selective photothermolysis of refractory port wine stains.

During the last three decades, several laser systems, ancillary technologies, and treatment modalities have been developed for the treatment of port wine stains (PWSs). However, approximately half of the PWS patient population responds suboptimally to laser treatment. Consequently, novel treatment modalities and therapeutic techniques/strategies are required to improve PWS treatment efficacy. This overview therefore focuses on three distinct experimental approaches for the optimization of PWS laser treatment. The approaches are addressed from the perspective of mechanical engineering (the use of local hypobaric pressure to induce vasodilation in the laser-irradiated dermal microcirculation), optical engineering (laser-speckle imaging of post-treatment flow in laser-treated PWS skin), and biochemical engineering (light- and heat-activatable liposomal drug delivery systems to enhance the extent of post-irradiation vascular occlusion).

In vitro quantitative assessment of total and bipolar shoulder arthroplasties: a biomechanical study using human cadaver shoulders.

BACKGROUND: Glenohumeral arthroplasty has produced results far inferior to those seen with hip and knee joint procedures. Therefore, the objective of this study was to evaluate the biomechanical parameters of the glenohumeral joint before and after total shoulder arthroplasty and bipolar hemiarthroplasty in 12 different positions simulating overhead activities. METHODS: Six matched pairs of cadaveric shoulders were used with a custom shoulder testing system to quantify the joint reactive force, contact areas, contact patterns and contact pressures in 12 different positions simulating overhead activities. The entire study was performed for the anatomic glenohumeral joint and following total shoulder arthroplasty on one side, and for the anatomic glenohumeral joint and following bipolar shoulder hemiarthroplasty on the contra-lateral side. FINDINGS: There was a significant increase in posterior force following total shoulder arthroplasty in two positions of horizontal adduction (P<0.05). In positions of increased glenohumeral abduction and horizontal adduction, the contact pressures and patterns were greatly altered following both total shoulder arthroplasty and bipolar hemiarthroplasty procedures compared to the anatomic state. INTERPRETATION: The alterations in joint reaction force, contact pressure and contact patterns following shoulder arthroplasty suggest a possible etiology for glenoid component edge loading in patients following total shoulder arthroplasty. This edge loading may lead to a rocking phenomenon of the glenoid component and subsequent loosening.

The effect of glenohumeral position on the shoulder after traumatic anterior dislocation.

BACKGROUND: Previous cadaveric studies suggest that positioning the shoulder in an externally rotated position reduces displaced Bankart lesions through a coaptation effect. HYPOTHESIS: We hypothesized that positioning the glenohumeral joint in an externally rotated position creates contact pressure between the subscapularis and the anterior labrum. STUDY DESIGN: Descriptive laboratory study. METHODS: Eight cadaveric shoulders were used. Contact pressure between the subscapularis and labrum was measured in varying glenohumeral positions using a Tekscan pressure monitor. The position of the anterior band of the inferior glenohumeral ligament was also digitized in those positions. All shoulders were tested in the intact condition, following a surgically created Bankart lesion and following anterior shoulder dislocation. These conditions were also verified by measuring glenohumeral translation and joint forces. RESULTS: For all 8 specimens, the contact pressure between the subscapularis and the anterior labrum was negligible with the humerus externally rotated up to 90 degrees at all abduction angles in intact, surgically created Bankart, and dislocated specimens. There were several glenohumeral positions where the anterior band of the inferior glenohumeral ligament strain in the intact specimens was similar to the postdislocation condition, that is, no statistically significant difference between intact and dislocated specimens. These positions included 30 degrees of glenohumeral abduction with external rotation between 0 degrees and 60 degrees, as well as 45 degrees of abduction with external rotation of 0 degrees and 60 degrees. The anterior band of the inferior glenohumeral ligament strain and glenohumeral anterior-posterior translation measurements revealed that the surgically created Bankart lesion does not simulate the conditions after anterior dislocation of the shoulder. CONCLUSION: External rotation of the shoulder does not create contact pressure between the subscapularis and the anterior labrum before or after anterior dislocation. CLINICAL RELEVANCE: The efficacy of external rotation immobilization after anterior-inferior shoulder dislocation is not likely to be related to coaptation of the Bankart lesion by the subscapularis.

Mal-aligning humeral offset may not effect shoulder hemiarthroplasty: a biomechanical study.

BACKGROUND: Component mal-positioning may contribute to a poor clinical outcome after hemiarthroplasty. Eccentric head components, recently introduced, allow posterior offset of the humeral head relative to the shaft so the purpose of this study was to determine effects of mal-aligning humeral head offset. MATERIAL/METHODS: Five glenohumeral joints were each placed in 60 and 90 degrees of shoulder abduction and in apprehension positions using a custom shoulder-testing device. Joint reaction force and contact areas, pressures and patterns were measured. Humeral head offset was then mal-aligned by rotating the eccentric head component 90 degrees and testing was repeated. RESULTS: There were no significant differences in the joint reaction forces in comparison of the hemiarthoplasies that mimicked and mal-aligned humeral offset. A significant increase in total contact area was found only at 60 degrees of abduction, increasing from 137.4+/-32.2 millimeters(2) to 243.4+/-27.0 millimeters(2). (p<0.05) No changes were found in contact pressures; only the patterns of contact were meaningfully different after hemiarthroplasty mal-aligned in humeral offset. In the apprehension position, rather than elongated ovals, there were multiple irregular patterns in the posterior joint. CONCLUSIONS: Meaningful alterations in joint biomechanics did not result from hemiarthroplasty that mal-aligned humeral offset, albeit the mal-alignments studied were small. Glenoid impingement with the humeral metaphysis may occur if portions of the humeral osteotomy surface, not covered by the head component, are not chamfered during the surgical procedure.

Glenohumeral joint translation after arthroscopic thermal capsuloplasty of the posterior capsule.

Treatment of recurrent posterior or multidirectional glenohumeral instability in athletes with traditional operative management has produced variable results at long-term follow-up. The purpose of this study was to determine whether an arthroscopic thermal capsuloplasty of the posterior capsule with a radiofrequency probe significantly decreases anterior-posterior glenohumeral translation. Successive posterior and anterior loads of 10, 15, and 20 N were applied sequentially to 7 cadaveric shoulder joints that were mounted in a translation testing apparatus with an electromagnetic tracking device measuring posterior and anterior glenohumeral translation. Arthroscopic thermal capsuloplasty was then performed on the posterior capsular tissue with a radiofrequency probe. The identical posterior-anterior loading protocol was then repeated, and translations were recorded. The results demonstrated no statistically significant differences in the mean posterior translation measurements before and after arthroscopic thermal capsuloplasty of the posterior capsule for the 10-N (+8.9%), 15-N (-3.1%), or 20-N (-1.8%) load (P >.50 to.62). Slightly greater changes occurred in anterior translation after posterior capsuloplasty at 10 N (-1.0%), 15 N (-6.0%), and 20 N (-10.3%). However, these changes were not found to be significant either (P =.06 to.62). The results of this study demonstrated that neither posterior nor anterior glenohumeral translation was significantly decreased by thermal capsuloplasty of the posterior capsule. Perhaps the lack of substantial collagenous material in the thin posterior capsule accounts for the inability of thermal capsuloplasty to be effective in this region.

Glenohumeral joint translation after arthroscopic thermal capsuloplasty of the rotator interval.

The treatment of recurrent anterior, posterior, or multidirectional glenohumeral instability by operative closure of the rotator interval has been proposed. The purpose of this study was to determine whether arthroscopic thermal capsuloplasty of the rotator interval with the radiofrequency probe significantly decreases anterior-posterior glenohumeral translation. Anterior and posterior loads of 10, 15, and 20 N were sequentially applied to 8 cadaveric shoulder joints while mounted in a translation testing apparatus with an electromagnetic tracking device measuring anterior and posterior glenohumeral translation. Arthroscopic thermal capsuloplasty was then performed on the rotator interval with a radiofrequency probe. The identical anterior-posterior loading protocol was then repeated, and translations were recorded. The results showed a significant reduction in anterior and posterior translation after thermal capsuloplasty. After rotator interval thermal capsuloplasty, anterior translation decreased by 31.5%, 28.8%, and 27.2% for the 10-, 15-, and 20-N loads, respectively. Posterior translation decreased by 43.1%, 43.8%, and 40.7%, respectively. The results of this study indicate that arthroscopic thermal capsuloplasty of the rotator interval is an effective way by which to decrease both anterior and posterior glenohumeral translation in vitro. To date, no in vivo studies that sufficiently document long-term clinically successful outcomes of such a procedure exist. Future studies are warranted to evaluate the effects of the biologic response to thermal shrinkage and whether these reduced glenohumeral translations will be maintained.