Preliminary results from the LUX-Dx insertable cardiac monitor remote programming and performance (LUX-Dx PERFORM) study.

Despite the wide adoption of insertable cardiac monitors (ICMs), high false-positive rates, suboptimal signal quality, limited ability to detect atrial flutter, and lack of remote programming remain challenging. The LUX-Dx PERFORM study was designed to evaluate novel technologies engineered to address these issues. Here, we present preliminary results from the trial focusing on the safety of ICM insertion, remote monitoring rates, and the feasibility of remote programming. LUX-Dx PERFORM is a multicenter, prospective, single-arm, post-market, observational study with planned enrollment of up to 827 patients from 35 sites in North America. A preliminary cohort consisting of the first 369 patients who were enrolled between March and October 2021 was selected for analysis. Three hundred sixty-three (363) patients had ICM insertions across inpatient and outpatient settings. The mean time followed was 103.4 ± 61.8 days per patient. The total infection rate was 0.8% (3/363). Interim results show high levels of remote monitoring with a median 94% of days with data transmission (interquartile range: 82-99). Thirteen (13) in-clinic and 24 remote programming sessions were reported in 34 subjects. Reprogramming examples are presented to highlight signal quality, the ability to detect atrial flutter, and the positive impact of remote programming on patient management. Interim results from LUX-Dx PERFORM study demonstrate the safety of insertion, high data transmission rates, the ability to detect atrial flutter, and the feasibility of remote programming to optimize arrhythmia detection and improve clinical workflow. Future results from LUX-Dx PERFORM will further characterize improvements in signal quality and arrhythmia detection.

Surface analysis of sequential semi-solvent vapor impact (SAVI) for studying microstructural arrangements of poly(lactide-co-glycolide) microparticles.

Biodegradable poly(lactide-co-glycolide) (PLGA) microparticles have been used as long-acting injectable (LAI) drug delivery systems for more than three decades. Despite extensive use, few tools have been available to examine and compare the three-dimensional (3D) structures of microparticles prepared using different compositions and processing parameters, all collectively affecting drug release kinetics. Surface analysis after sequential semi-solvent impact (SASSI) was conducted by exposing PLGA microparticles to different semi-solvent in the liquid phase. The use of semi-solvent liquids presented practical experimental difficulties, particularly in observing the same microparticles before and after exposure to semi-solvents. The difficulties were overcome by using a new sequential semi-solvent vapor (SSV) method to examine the morphological changes of the same microparticles. The SASSI method based on SSV is called surface analysis of semi-solvent vapor impact (SAVI). Semi-solvents are the solvents that dissolve PLGA polymers depending on the polymer's lactide:glycolide (L:G) ratio. A sequence of semi-solvents was used to dissolve portions of PLGA microparticles in an L:G ratio-dependent manner, thus revealing different structures depending on how microparticles were prepared. Exposing PLGA microparticles to semi-solvents in the vapor phase demonstrated significant advantages over using semi-solvents in the liquid phase, such as in control of exposure conditions, access to imaging, decreasing the time for sequential exposure of semi-solvents, and using the same microparticles. The SSV approach for morphological analysis provides another tool to enhance our understanding of the microstructural arrangement of PLGA polymers. It will improve our comprehensive understanding of the factors controlling drug release from LAI formulations based on PLGA polymers.

Scanning Analysis of Sequential Semisolvent Vapor Impact To Study Naltrexone Release from Poly(lactide-co-glycolide) Microparticles.

Poly(lactide-co-glycolide) (PLGA)-based microparticle formulations have been a mainstay of long-acting injectable drug delivery applications for decades. Despite a long history of use, tools and techniques to analyze and understand these formulations are still under development. Recently, a new characterization method was introduced known as the surface analysis after sequential semisolvent impact using sequential semisolvent vapors. The vapor-based technique is named, for convenience, surface analysis of (semisolvent) vapor impact (SAVI). In the SAVI method, discretely controlled quantities of selected organic semisolvents in the vapor phase were applied to PLGA microparticles to track particle morphological changes by laser scanning confocal microscopy. Subsequently, the morphological images were analyzed to calculate mean peak height (Sa), core height (Sk), kurtosis (Sku), dale void volume (Vvv), the density of peaks (Spd), maximum height (Hm), and the shape ratio (Rs). Here, the SAVI method was applied to naltrexone-loaded microparticles manufactured internally and Vivitrol, a commercial formulation. SAVI analysis of these microparticles indicated that the two primary mechanisms controlling the naltrexone release were the formation of discrete, self-crystallized portions of naltrexone within the PLGA structure and the degradation of PLGA chains through nucleophilic substitution. The relatively higher amounts of naltrexone crystals resulted in prolonged release than lower amounts of crystals. Data from gel permeation chromatography, differential scanning calorimetry, and in vitro release measurements all point to the importance of naltrexone crystal formation. This study highlights the utility of SAVI for gaining further insights into the microstructure of PLGA formulations and using SAVI data to support research, product development, and quality control applications for microparticle formulations of pharmaceuticals.

Impact of shoe and cleat type on youth baseball pitching biomechanics.

Shoulder and elbow injuries among baseball pitchers of various ages and abilities continue to rise despite exhaustive efforts analysing pitch type and count; however, it has yet been determined if footwear plays a role in altering pitching mechanics and subsequently injury susceptibility. Therefore, the purpose of the study was to investigate the effect footwear might have on youth baseball pitching mechanics. Data were collected on eleven youth baseball pitchers wearing two different shoes on two different surface inclinations. A repeated measures ANOVA was utilised to determine differences between upper and lower extremity joint kinematics and kinetics (p < 0.05). Results indicate wearing moulded cleats elicited significantly greater amounts of shoulder internal rotation torque, angle and velocity as well as elbow varus torque. Turf shoes caused an increased plantarflexion joint angle in the stride leg ankle and shoulder external rotation torque, angle and velocity. The findings of this study suggest that the footwear worn by a youth baseball pitcher does alter the shoulder and elbow dynamics in the dominant throwing arm as well as the amount of ankle plantarflexion in the stride leg.

Sensory Organization Test Conditions Influence Postural Strategy Rather than Footwear or Workload.

BACKGROUND: Postural strategies such as ankle, hip, or combined ankle-hip strategies are used to maintain optimal postural stability, which can be influenced by the footwear type and physiological workload. PURPOSE: This paper reports previously unreported postural strategy scores during the six conditions of the sensory organization test (SOT). METHODS: Fourteen healthy males (age: 23.6 ± 1.2 years; height: 181 ± 5.3 cm; mass: 89.2 ± 14.6 kg) were tested for postural strategy adopted during SOT in three types of occupational footwear (steel-toed work boot, tactical work boot, low-top work shoe) every 30 min during a 4-h simulated occupational workload. Postural strategy scores were analyzed using repeated measures analysis of variance at 0.05 alpha level. RESULTS: Significant differences among postural strategy scores were only evident between SOT conditions, and but not between footwear type or the workload. CONCLUSIONS: Findings indicate that occupational footwear and occupational workload did not cause a significant change in reliance on postural strategies. The significant changes in postural strategy scores were due to the availability of accurate and/or conflicting sensory feedback during SOT conditions. In SOT conditions where all three types of sensory feedback was available, the ankle strategy was predominantly adopted, while more reliance on hip strategy occurred in conditions with absent or conflicting sensory feedback.

Development of alginate and gelatin-based pleural and tracheal sealants.

Pleural and tracheal injuries remain significant problems, and an easy to use, effective pleural or tracheal sealant would be a significant advance. The major challenges are requirements for adherence, high strength and elasticity, dynamic durability, appropriate biodegradability, and lack of cell or systemic toxicity. We designed and evaluated two sealant materials comprised respectively of alginate methacrylate and of gelatin methacryloyl, each functionalized by conjugation with dopamine HCl. Both compounds are cross-linked into easily applied as pre-formed hydrogel patches or as in situ hydrogels formed at the wound site utilizing FDA-approved photo-initiators and oxidants. Material testing demonstrates appropriate adhesiveness, tensile strength, burst pressure, and elasticity with no significant cell toxicity in vitro assessments. Air-leak was absent after sealant application to experimentally-induced injuries in ex-vivo rat lung and tracheal models and in ex vivo pig lungs. Sustained repair of experimentally-induced pleural injury was observed for up to one month in vivo rat models and for up to 2 weeks in vivo rat tracheal injury models without obvious air leak or obvious toxicities. The alginate-based sealant worked best in a pre-formed hydrogel patch whereas the gelatin-based sealant worked best in an in situ formed hydrogel at the wound site thus providing two potential approaches. These studies provide a platform for further pre-clinical and potential clinical investigations. STATEMENT OF SIGNIFICANCE: Pneumothorax and pleural effusions resulting from trauma and a range of lung diseases and critical illnesses can result in lung collapse that can be immediately life-threatening or result in chronic leaking (bronchopleural fistula) that is currently difficult to manage. This leads to significantly increased morbidity, mortality, hospital stays, health care costs, and other complications. We have developed sealants originating from alginate and gelatin biomaterials, each functionalized by methacryloylation and by dopamine conjugation to have desired mechanical characteristics for use in pleural and tracheal injuries. The sealants are easily applied, non-cytotoxic, and perform well in vitro and in vivo model systems of lung and tracheal injuries. These initial proof of concept investigations provide a platform for further studies.

Comparison of Countermovement and Squat Jumps Performance in Recreationally Trained Males.

The vertical jump has been shown to be an effective tool in assessing neuromuscular fatigue. The two most common iterations of the vertical jump are the countermovement and squat jumps. This investigation sought to identify if differences exist between the two jumping strategies with regard to electromyography (EMG) and kinetics in a group of recreationally trained males. Twenty-two participants completed one experimental session, where three countermovement (CMJ) and three squat jumps (SJ) were performed using a counterbalanced within-subject design. Jump performance was evaluated with data obtained using a force platform. Additionally, EMG was collected on the vastus lateralis (VL), vastus medialis (VM), semitendinosus (ST) and medial gastrocnemius (MG). Greater EMG values were seen in the CMJ for ST as well as percentage of activation in the MG (p < 0.05). Increased values of mean force and mean power were observed in the SJ, while the CMJ showed greater peak and mean velocity. Greater jump heights in the CMJ were present as well (p < 0.05). These findings suggest that the increase in CMJ jump height due to the increase in propulsive velocity is not due to increases in knee extensors muscle activation.

Analysis of semi-solvent effects for PLGA polymers.

Poly(lactide-co-glycolide) polymers (PLGAs) have been used in many clinical formulations of injectable, long-acting formulations. Frequently, PLGAs having different lactide:glycolide (L:G) ratios, molecular weights (MWs), end-groups, and molecular structures have been used individually or in mixtures. To understand the properties of existing formulations made of PLGAs and to develop new formulations, understanding PLGA properties is essential. Yet, the separation of individual PLGA components from a mixture and their characterization has been challenging due to an incomplete understanding of PLGAs. This study focuses on separating PLGAs based on their molecular properties, such as L:G ratio, molecular weight, and comonomer sequence. The separation of PLGAs exploits the use of semi-solvents that dissolve only PLGAs having lactide contents (L%) above a certain threshold. More semi-solvents have been identified that show a specific transition L% between 50 and 100%. The mechanism study of semi-solvents indicates that semi-solvents, in general, prefer PLGAs with relatively higher L%, lower molecular weight, and higher G-L sequences as opposed to G-G sequences. The examination of a series of esters and ketones indicates that a solvent with lower molar volume is more effective as a semi-solvent. At a similar molar volume, esters are more effective than ketones in dissolving PLGAs with the same L:G ratio. The ability to separate and identify PLGA fractions allows better characterization of existing formulations and higher flexibility in designing new injectable, long-acting PLGA formulations.

Lower Extremity Muscle Activation in Alternative Footwear during Stance Phase of Slip Events.

Muscle activity from the slipping leg have been previously used to analyze slip induced falls. However, the impact of casual alternative footwear on slipping leg muscle activity when exposed to slippery environments is still unknown. The purpose of the study was to analyze the impact of alternative footwear (crocs (CC) and flip-flops (FF)) compared to slip-resistant footwear (LT) on lower extremity muscle activity when exposed to dry gait (NG), unexpected (US), alert (AS), and expected slips (ES). Eighteen healthy males (age: 22.3 ± 2.2 years; height: 177.7 ± 6.9 cm; weight: 79.3 ± 7.6 kg) completed the study in a repeated measures design in three footwear sessions separated by 48 h. Electromyography (EMG) muscle activity from four muscles of the lead/slipping leg was measured during the stance phase of the gait-slip trials. A 3 (footwear) × 4 (gait-slip trials) repeated measures analysis of variance was used to analyze EMG dependent variables mean, peak, and percent of maximal voluntary contraction. Greater lower extremity muscle activation during the stance phase was seen in US and AS conditions compared to NG and ES. In addition, footwear differences were seen for the alternative footwear (CC and FF) during US and AS, while the low top slip resistant shoe had no differences across all gait trials, suggesting it as the most efficient footwear of choice, especially when maneuvering slippery flooring conditions, either with or without the knowledge of an impending slip.

Potential Roles of the Glass Transition Temperature of PLGA Microparticles in Drug Release Kinetics.

Poly(lactic-co-glycolic acid) (PLGA) has been used for long-acting injectable drug delivery systems for more than 30 years. The factors affecting the properties of PLGA formulations are still not clearly understood. The drug release kinetics of PLGA microparticles are influenced by many parameters associated with the formulation composition, manufacturing process, and post-treatments. Since the drug release kinetics have not been explainable using the measurable properties, formulating PLGA microparticles with desired drug release kinetics has been extremely difficult. Of the various properties, the glass transition temperature, Tg, of PLGA formulations is able to explain various aspects of drug release kinetics. This allows examination of parameters that affect the Tg of PLGA formulations, and thus, affecting the drug release kinetics. The impacts of the terminal sterilization on the Tg and drug release kinetics were also examined. The analysis of drug release kinetics in relation to the Tg of PLGA formulations provides a basis for further understanding of the factors controlling drug release.

Formulation composition, manufacturing process, and characterization of poly(lactide-co-glycolide) microparticles.

Injectable long-acting formulations, specifically poly(lactide-co-glycolide) (PLGA) based systems, have been used to deliver drugs systemically for up to 6 months. Despite the benefits of using this type of long-acting formulations, the development of clinical products and the generic versions of existing formulations has been slow. Only about two dozen formulations have been approved by the U.S. Food and Drug Administration during the last 30 years. Furthermore, less than a dozen small molecules have been incorporated and approved for clinical use in PLGA-based formulations. The limited number of clinically used products is mainly due to the incomplete understanding of PLGA polymers and the various variables involved in the composition and manufacturing process. Numerous process parameters affect the formulation properties, and their intricate interactions have been difficult to decipher. Thus, it is necessary to identify all the factors affecting the final formulation properties and determine the main contributors to enable control of each factor independently. The composition of the formulation and the manufacturing processes determine the essential property of each formulation, i.e., in vivo drug release kinetics leading to their respective pharmacokinetic profiles. Since the pharmacokinetic profiles can be correlated with in vitro release kinetics, proper in vitro characterization is critical for both batch-to-batch quality control and scale-up production. In addition to in vitro release kinetics, other in vitro characterization is essential for ensuring that the desired formulation is produced, resulting in an expected pharmacokinetic profile. This article reviews the effects of a selected number of parameters in the formulation composition, manufacturing process, and characterization of microparticle systems. In particular, the emphasis is focused on the characterization of surface morphology of PLGA microparticles, as it is a manifestation of the formulation composition and the manufacturing process. Also, the implication of the surface morphology on the drug release kinetics is examined. The information described here can also be applied to in situ forming implants and solid implants.

Impact of Hydration Status on Jump Performance in Recreationally Trained Males.

The vertical jump is commonly used as a means of evaluating athlete readiness. Athletes have been shown to arrive to training and competition in a hypohydrated state. Thus, this investigation sought to examine the impact of hydration status on both countermovement (CMJ) and squat jump (SJ) performance. Twenty-five recreationally trained males completed three CMJ and SJ in a euhydrated, hypohydrated and control condition. Conditions were separated by a minimum of 24 hours. Hydration status was assessed using urine specific gravity. Jump performance was evaluated using both kinematic and kinetic data obtained from a force platform. A repeated-measures ANOVA was performed for each variable of interest in both the CMJ and SJ. CMJ peak and mean force values were significantly greater in the euhydrated condition compared to the hypohydrated condition (p < 0.05), with no differences between the control condition and either experimental condition. SJ showed reductions in jump height, peak and mean velocity, peak and mean power and impulse from control and euhydrated conditions (p < 0.05). The findings of this investigation show that when performing jump testing, specifically SJ, that hydration status of the individual may impact commonly used variables to assess the readiness of the individual for a given day.

Method matters: Development of characterization techniques for branched and glucose-poly(lactide-co-glycolide) polymers.

Defining the qualitative sameness of parenteral formulations comprised of poly(lactide-co-glycolide) (PLGA) requires assays of the relevant properties of polymer from each formulation. Gel-permeation chromatography with quaternary detection (GPC-4D) has been previously applied to other polymers, and the relevant mathematical parameters for their characterization are available; however, such parameters have not been described for branched PLGA polymers. Little information is available for the determination of glucose within glucose-PLGA (Glu-PLGA) branched polymers. This study describes the experimental methods of defining the mathematical parameters for characterization of branched PLGA polymers and the validation of these parameters using known branched-PLGA standards. The glucose, used as an initiator, was tracked through the synthesis of Glu-PLGA by both 13C NMR and enzymatic analysis. The analytical determination of the relevant parameters defining Glu-PLGA, such as the branching number, and the presence of glucose, requires the use of appropriate procedures experimentally validated in a systematic manner. The procedures described in this study were developed for characterization of Glu-PLGA with the lactide:glycolide (L:G) ratio of 55:45 used in Sandostatin® LAR. The procedures can also be used for characterization of Glu-PLGAs made of different L:G ratios.

The Interaction of Cognitive Interference, Standing Surface, and Fatigue on Lower Extremity Muscle Activity.

BACKGROUND: Performing cognitive tasks and muscular fatigue have been shown to increase muscle activity of the lower extremity during quiet standing. A common intervention to reduce muscular fatigue is to provide a softer shoe-surface interface. However, little is known regarding how muscle activity is affected by softer shoe-surface interfaces during static standing. The purpose of this study was to assess lower extremity muscular activity during erect standing on three different standing surfaces, before and after an acute workload and during cognitive tasks. METHODS: Surface electromyography was collected on ankle dorsiflexors and plantarflexors, and knee flexors and extensors of fifteen male participants. Dependent electromyography variables of mean, peak, root mean square, and cocontraction index were calculated and analyzed with a 2 × 2 × 3 within-subject repeated measures analysis of variance. RESULTS: Pre-workload muscle activity did not differ between surfaces and cognitive task conditions. However, greater muscle activity during post-workload balance assessment was found, specifically during the cognitive task. Cognitive task errors did not differ between surface and workload. CONCLUSIONS: The cognitive task after workload increased lower extremity muscular activity compared to quite standing, irrespective of the surface condition, suggesting an increased demand was placed on the postural control system as the result of both fatigue and cognitive task.

Cell Culture and Coculture for Oncological Research in Appropriate Microenvironments.

With the increase in knowledge on the importance of the tumor microenvironment, cell culture models of cancers can be adapted to better recapitulate physiologically relevant situations. Three main microenvironmental factors influence tumor phenotype: the biochemical components that stimulate cells, the fibrous molecules that influence the stiffness of the extracellular matrix, and noncancerous cells like epithelial cells, fibroblasts, endothelial cells, and immune cells. Here we present methods for the culture of carcinomas in the presence of a matrix of specific stiffness, and for the coculture of tumors and fibroblasts as well as epithelial cells in the presence of matrix. Information is provided to help with choice and assessment of the matrix support and in working with serum-free medium. Using the example of a tissue chip recapitulating the environmental geometry of carcinomas, we also highlight the development of engineered platforms that provide exquisite control of cell culture parameters necessary in research and development. © 2019 by John Wiley & Sons, Inc.

Characterization of branched poly(lactide-co-glycolide) polymers used in injectable, long-acting formulations.

Poly(lactide-co-glycolide) (PLGA) has been used in many injectable, long-acting depot formulations. Despite frequent use of PLGA, however, its characterization has been limited to measuring its molecular weight, lactide:glycolide (L:G) ratio, and end-group. These conventional methods are not adequate for characterization of unique PLGA polymers, such as branched PLGA. Glucose-initiated PLGA (Glu-PLGA) has been used in Sandostatin® LAR Depot (octreotide acetate for injectable suspension) approved by the U.S. Food and Drug Administration (FDA) in 1998. Glu-PLGA is a branched (also known as star-shaped) polymer and determining its properties has been challenging. It is necessary to develop methods that can determine and characterize the branching parameters of Glu-PLGA. Such characterization is important not only for the quality control of formulations, but also for developing generic parenteral formulations that are required to have the same excipients in the same amount (qualitative/quantitative (Q1/Q2) sameness) as their Reference Listed Drug (RLD). In this study, an analytical technique was developed and validated using a series of branched-PLGA standards, and it was used to determine the branching parameters of Glu-PLGA extracted from Sandostatin LAR, as well as Glu-PLGAs obtained from three different manufacturers. The analytical technique was based on gel-permeation-chromatography with quadruple detection systems (GPC-4D). GPC-4D enabled characterization of Glu-PLGA in its concentration, absolute molecular weight, hydrodynamic radius and intrinsic viscosity. The plot of the branch units per molecule as a function of molar mass provides a unique profile of each branched PLGA. The Mark-Houwink plots were also used to distinguish different Glu-PLGAs. These ensemble identification methods indicate that the branch units of Glu-PLGAs extracted from Sandostatin LAR range from 2 (i.e., linear) at the lower end of the molecular weight to <4 for the majority (94%) of Glu-PLGA.

Injectable, long-acting PLGA formulations: Analyzing PLGA and understanding microparticle formation.

Injectable, long-acting depot formulations based on poly(lactide-co-glycolide) (PLGA) have been used clinically since 1989. Despite 30 years of development, however, there are only 19 different drugs in PLGA formulations approved by the U.S. Food and Drug Administration (FDA). The difficulty in developing depot formulations stems in large part from the lack of a clear molecular understanding of PLGA polymers and a mechanistic understanding of PLGA microparticles formation. The difficulty is readily apparent by the absence of approved PLGA-based generic products, limiting access to affordable medicines to all patients. PLGA has been traditionally characterized by its molecular weight, lactide:glycolide (L:G) ratio, and end group. Characterization of non-linear PLGA, such as star-shaped glucose-PLGA, has been difficult due to the shortcomings in analytical methods typically used for PLGA. In addition, separation of a mixture of different PLGAs has not been previously identified, especially when only their L:G ratios are different while the molecular weights are the same. New analytical methods were developed to determine the branch number of star-shaped PLGAs, and to separate PLGAs based on L:G ratios regardless of the molecular weight. A deeper understanding of complex PLGA formulations can be achieved with these new characterization methods. Such methods are important for further development of not only PLGA depot formulations with controllable drug release kinetics, but also generic formulations of current brand-name products.

Complex sameness: Separation of mixed poly(lactide-co-glycolide)s based on the lactide:glycolide ratio.

Poly (lactide-co-glycolide) (PLGA) has been used for making injectable, long-acting depot formulations for the last three decades. An in depth understanding of PLGA polymers is critical for development of depot formulations as their properties control drug release kinetics. To date, about 20 PLGA-based formulations have been approved by the U.S. Food and Drug Administration (FDA) through new drug applications, and none of them have generic counterparts on the market yet. The lack of generic PLGA products is partly due to difficulties in reverse engineering. A generic injectable PLGA product is required to establish qualitative and quantitative (Q1/Q2) sameness of PLGA to that of a reference listed drug (RLD) to obtain an approval from the FDA. Conventional characterizations of PLGA used in a formulation rely on measuring the molecular weight by gel permeation chromatography (GPC) based on polystyrene molecular weight standards, and determining the lactide:glycolide (L: G) ratio by 1H NMR and the end-group by 13C NMR. These approaches, however, may not be suitable or sufficient, if a formulation has more than one type of PLGA, especially when they have similar molecular weights, but different L:G ratios. Accordingly, there is a need to develop new assay methods for separating PLGAs possessing different L:G ratios when used in a drug product and characterizing individual PLGAs. The current work identifies a series of semi-solvents which exhibit varying degrees of PLGA solubility depending on the L:G ratio of the polymer. A good solvent dissolves PLGAs with all L:G ratios ranging from 50:50 to 100:0. A semi-solvent dissolves PLGAs with only certain L:G ratios. Almost all semi-solvents identified in this study increase their PLGA solubility as the L:G ratio increases, i.e., the lactide content increases. This lacto-selectivity, favoring higher L:G ratios, has been applied for separating individual PLGAs in a given depot formulation, leading to analysis of each type of PLGA. This semi-solvent method allows a simple, practical bench-top separation of PLGAs of varying L:G ratios. This method enables isolation and identification of individual PLGAs from a complex mixture that is critical for the quality control of PLGA formulations, as well as reverse engineering for generic products to establish the Q1/Q2 sameness.

Reshapable hydrogel tissue expander for ridge augmentation: Results of a series of successive insertions at the same intraoral site.

BACKGROUND: Oral mucosa expansion before ridge augmentation is a procedure to reduce soft tissue exposure and to improve bone graft density and volume after augmentation. This study explored a novel, shapeable hydrogel tissue expander (HTE) in intraoral sites that had undergone previous expansion and surgery. METHODS: Nine beagle dogs had all premolar teeth extracted and adjacent alveolar bone reduced. After at least 3 months healing hydrogels were placed at 4 sites in each dog: maxilla and mandible, right and left. After 6 weeks of expansion, the hydrogels were removed and measured for volume expansion and physical condition. Punch biopsies were taken of the expanded oral mucosa. After 3 months, a second hydrogel insertion was performed at each of the same sites. After this second expansion cycle, volume and hydrogel condition were recorded. Three dogs received ultrasound imaging of the hydrogels during the second expansion. Necropsy specimens were taken of both expanded and non-expanded oral mucosa. RESULTS: Within 2 weeks after HTE insertion in both first and second insertions, blood flow returned to the pre-insertion level. The first and second insertions resulted in linear oral mucosa gain of 8.13 mm, and 6.44 mm, respectively. First and second insertion hydrogels erupted from 4% of the first expansion sites, and 3% of the second expansion sites. There was no directional migration of the expanding hydrogel at any site. Histology found little inflammatory reaction to any hydrogel implant. CONCLUSION: Oral mucosa can be consistently and successfully expanded before bone graft for ridge augmentation even at sites with a history of prior surgeries.

The Effects of Various Weighted Implements on Baseball Swing Kinematics in Collegiate Baseball Players.

Williams, CC, Gdovin, JR, Wilson, SJ, Cazas-Moreno, VL, Eason, JD, Hoke, EL, Allen, CR, Wade, C, and Garner, JC. The effects of various weighted implements on baseball swing kinematics in collegiate baseball players. J Strength Cond Res 33(5): 1347-1353, 2019-The purpose of this study was to investigate the effects of different warm-up (WU) devices on bat swing parameters including maximal resultant velocity (MRV), resultant velocity at ball contact (RVBC), time difference between MRV and RVBC, bat angle at MRV, bat angle at RVBC, and perceptual differences of each WU implement used by National Collegiate Athletic Association Division-I baseball players. Fifteen varsity baseball players completed 1 experimental session during fall training. Retroreflective markers were placed on the bat and tee to measure basic bat kinematics during the swing. Participants completed a general calisthenics WU before being counter-balanced into 1 of 4 WU conditions: standard bat (SB) (33 in/30 oz), fungo (10.6 oz), weighted gloves with SB (weighted gloves) (55.6 oz) and donut with SB (donut) (55.6 oz). Each participant was asked to perform their normal on-deck routine over a 2-minute period, finishing with 5 practice swings with the designated condition. After completion of the WU, a 1-minute rest period (simulating normal game conditions) was given to allow each participant to get set to perform 5 maximal swings with a SB. Five, 1 × 4 (group × condition) repeated measures analysis of variance examined the aforementioned variables. There were no significant differences in MRV, RVBC, time difference between MRV and RVBC, and bat angle at MRV and RVBC between all WU conditions. If presented with the current options, athletes should choose the WU implement with which they are most comfortable using before an at-bat situation.