Background-This study aimed to correlate oesophageal bolus transit with features of oesophageal pressure topography (OPT) plots and establish OPT metrics for accurately measuring peristaltic velocity.

This review critically analyses the chemical and physical parameters that influence the occurrence of opportunistic pathogens in the drinking water distribution system, specifically in premise plumbing. A comprehensive literature review reveals significant impacts of water age, disinfectant residual (type and concentration), temperature, pH, and pipe materials. Evidence suggests that there is substantial interplay between these parameters; however, the dynamics of such relationships is yet to be elucidated. There is a correlation between premise plumbing system characteristics, including those featuring water and energy conservation measures, and increased water quality issues and public health concerns. Other interconnected issues exacerbated by high water age, such as disinfectant decay and reduced corrosion control efficiency, deserve closer attention. Some common features and trends in the occurrence of opportunistic pathogens have been identified through a thorough analysis of the available literature. It is proposed that the efforts to reduce or eliminate their incidence might best focus on these common features.

Gene trap mutagenesis is a powerful tool to create loss-of-function mutations in mice and other model organisms. Modifications of traditional gene trap cassettes, including addition of conditional features in the form of Flip-excision (FlEx) arrays to enable directional gene trap cassette inversions by Cre and Flpe site-specific recombinases, greatly enhanced their experimental potential. By taking advantage of these conditional gene trap cassettes, we developed a generic strategy for generating conditional mutations and validated this strategy in mice carrying a multipurpose allele of the Prdm16 transcription factor gene. We demonstrate that the gene trap insertion creates a null mutation replicating the Pierre Robin sequence-type cleft palate phenotype of other Prdm16 mutant mice. Consecutive breeding to Flpe and Emx1IREScre deleter mice spatially restricted Prdm16 loss to regions of the forebrain expressing the homeobox gene Emx1, demonstrating the utility of the technology for the analysis of tissue-specific gene functions.

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Craniometric studies on the hylobatids using external metrics (Creel and Preuschoft, 1976, 1984) sorted hylobatid populations into primary species groupings which are in accordance with the four currently recognized generic-level groupings. The goal of the current study was to assess the relative orientations of the orbits, palate, and basioccipital clivus among the hylobatid genera in an effort to further clarify whether the lesser apes differ significantly in these internal cranial features and how that variation patterns across the groups. Nine angular variables quantifying orbital, palatal, and basioccipital clivus orientations were measured on lateral view radiographs of adults representing three of the four hylobatid genera: Hylobates; Nomascus; and, Symphalangus. The interspecific adult hylobatid means for the angular variables were analyzed using t-test contrasts. The total sample was further subjected to discriminant function analysis (DFA) to test for the ability of craniofacial angular variables to distinguish the hylobatid genera from one another. The three hylobatid genera displayed significant morphological differentiation in orbital, palatal, and posterior skull base orientations. Normal, jackknifed, and cross-validation DFA procedures correctly identified the hylobatids 50-100% of the time. The observed morphological patterns generally mapped onto the findings of earlier external craniometric hylobatid studies and suggest concordance between specific internal and external cranial features. This article is the first comprehensive study of variation in internal cranial anatomy of the Hylobatidae and includes the first published craniofacial angular data for Nomascus.

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This study is part of a larger project examining the role of Prdm16, a transcriptional cofactor involved in TGF‐β signaling pathways, on craniofacial development. Prdm16 is expressed in various tissues, including cranial neural crest and the brain. Two, Prdm16 mutant mouse models, cleft secondary palate‐1 on a C57Bl6/J background strain (csp1) and Prdm16 conditional gene trap on an FVB/NJ background strain (cGT), display non‐syndromic clefting of the secondary palate and micrognathia due to loss of Prdm16 function. Our earlier pilot project on adult cGT and csp1 mice revealed that cGT heterozygous mutants have a relatively narrower skulls compared to their wild type (wt) littermates and that csp1 heterozygous mutants have relatively wider skulls than their wt counterparts. Homozygous mutants of both strains die shortly after birth. The aim of this study is to quantitatively assess variation in bony neurocranial development in newborn het and mut csp1 and cGT mice and contrast this with the wt morphology to determine if variation in degree of bone development in these strains is apparent at the newborn stage. Crania of newborn heterozygous mutant, homozygous mutant, and wt csp1 and cGT mice were microCT scanned and the resulting 2D images were volume‐merged to create a 3D model for each specimen. The neurocranial bones from each 3D model were segmented into separate images for analysis. For each specimen, we calculated the surface area and volume of each neurocranial bone and statistically compared these values among the genotype groupings. Smaller bone surface areas and volumes were interpreted as indicating less bone development. Homozygous mutant mice of both strains had significantly less developed neurocranial bones than their wt counterparts. The heterozygous mutant mice in both strains displayed substantial variation in degree of bone development. The calvarial bones were especially under‐developed in homozygous mutant csp1 and cGT mice, but the occipital and alisphenoid bones were well‐developed in most specimens. Our results suggest that reduced Prdm16 expression in newborn homozygous mutant csp1 and cGT mice correlates with overall underdevelopment of the neurocranium compared to wt mice. Bone development patterns in the heterozygous mutant mice are less apparent and require additional analysis. These findings complement our previous research on adult csp1 and cGT mice and additional insight on the downstream effects of Prdm16 expression on craniofacial development. Support or Funding Information NIH/NIDCR (R15DE023982) and Midwestern University Core Facility

Variations in lateral ankle anatomy may predispose individuals to injury in certain foot positions or activities. The orthopedics literature notes that a “low‐lying muscle belly” of the fibularis brevis muscle, defined by some as extending distal to the tip of the lateral malleolus, is a risk factor for fibularis brevis tendon injuries. Past studies document this finding in pathologic ankles during clinical evaluation and treatment. However, the normal range of variation in fibularis brevis (FB) and fibularis longus (FL) muscle fiber and tendon morphology is unknown.The goal of this study was to survey a cadaveric sample for normal gross anatomical variations in muscle fiber and tendon morphology of the FB and FL muscles and to analyze these traits with respect to body size and sex in a general population.We dissected 66 preserved foot and leg specimens from a mixed‐sex sample of 33 adult individuals to analyze soft tissue variation in the lateral ankle region. No evidence of tearing or splitting was grossly observable in any of the tendons. All specimens appeared to have intact superior and inferior fibular retinacular complexes. We took twelve linear measurements on each specimen with the foot in 90° dorsiflexion. We performed Pearson's correlation analyses of muscle fiber dimensions against foot length as a body size surrogate. We also performed two‐tailed, t‐test contrasts between female and male size‐controlled measurement means to test for sex‐related differences.The muscle fibers on the anterior and posterior surfaces of the FB and FL muscles typically terminate at different locations. In two females and four males, the posterior surface fibers of the FB muscle on the right and/or left sides terminated inferior to the tip of the lateral malleolus. In all other cases, the FB and FL muscle fibers terminated superior to the fibular tip. There were no statistically significant differences between size‐controlled mean female and male muscle fiber dimensions. However, in females, the extents of the right and left FL muscle fibers were significantly moderately to strongly correlated with foot length (r=0.52–0.71; p=0.004–0.05). In females, the extent of the right posterior surface FB fibers were also significantly moderately correlated with foot length (r=−0.59; p=0.02), but negatively. No significant correlations between muscle fiber extent and body size were detected in the male sample.There is weak evidence for a body size effect in FB and FL muscle fibers in females, but no evidence for overall sex‐related or body size effects in the morphology of these muscles. Our findings along with the historical documented presence of FB muscle fibers extending into and distal to the fibular groove in pathological individuals supports the contention that this condition may predispose an individual to ankle injury. However, the lateral ankle is a complex structure and multiple factors are likely to be involved in ankle instability.Support or Funding InformationMidwestern University, Federal Work‐Study ProgramThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.