Muscle Type Research Articles

Comparison of physiologically functional compounds in Sika deer Cervus nippon meats obtained from different regions in Japan.

In Japan, the promotion of effective use of many wild deer as food resource has been conducted. However, they are not necessarily utilized effectively. Thus, we focused physiologically functional compounds to find characteristics of Sika deer meats (commercially available) obtained from different regions such as Hokkaido, Wakayama, Tokushima, and Miyazaki prefectures in Japan, making it a valuable resource for future studies and applications. The amount of carnosine, anserine, and balenine in muscle of deer from Wakayama prefecture was significantly lower than that in muscle of deer from other prefectures. The differences of amount of imidazole dipeptides in different prefectures seems to be caused by feed, rearing environment, and breed. The amount of carnitine in deer meat from Hokkaido was significantly lower than that in muscle of deer from other prefectures, while the amount of acetyl-carnitine in deer meat from Miyazaki prefectures was significantly higher than that from other prefectures. The amounts of glutamine, ornithine, and 3-methylhistidine in muscles of deer from Wakayama prefectures were significantly higher than those in muscle of deer from other prefectures. These results might be caused by differences in feeding habits, habitat, the muscle types, and subspecies of deer obtained from four regions in Japan.

Investigating the role of CFTR in human and mouse myometrium

BackgroundAbnormal cystic fibrosis transmembrane conductance regulator (CFTR) function in cystic fibrosis (CF) has been linked to airway smooth muscle abnormalities including bronchial hyperresponsiveness. However, a role for CFTR in other types of smooth muscle, including myometrium, remains largely unexplored. As CF life expectancy and the number of pregnancies increases, there is a need for an understanding of the potential role of CFTR in myometrial function. MethodsWe investigated the role of CFTR in human and mouse myometrium. We used immunofluorescence to identify CFTR expression, and carried out contractility studies on spontaneously contracting term pregnant and non-pregnant mouse myometrium and term pregnant human myometrial biopsies from caesarean sections. ResultsCFTR was found to be expressed in term pregnant mouse myometrium. Inhibition of CFTR, with the selective inhibitor CFTRinh-172, significantly reduced contractility in pregnant mouse and human myometrium in a concentration-dependent manner (44.89 ± 11.02 term pregnant mouse, 9.23 ± 4.75 term-pregnant human; maximal effect at 60 μM expressed as a percentage of the pre-treatment control period). However, there was no effect of CFTRinh-172 in non-pregnant myometrium. ConclusionThese results demonstrate decreased myometrial function when CFTR is inhibited, which may have implications on pregnancy and labour outcome and therapeutic decisions for labour in CF patients.

Deep learning-based respiratory muscle segmentation as a potential imaging biomarker for respiratory function assessment.

Respiratory diseases significantly affect respiratory function, making them a considerable contributor to global mortality. The respiratory muscles play an important role in disease prognosis; as such, quantitative analysis of the respiratory muscles is crucial to assess the status of the respiratory system and the quality of life in patients. In this study, we aimed to develop an automated approach for the segmentation and classification of three types of respiratory muscles from computed tomography (CT) images using artificial intelligence. With a dataset of approximately 600,000 thoracic CT images from 3,200 individuals, we trained the model using the Attention U-Net architecture, optimized for detailed and focused segmentation. Subsequently, we calculated the volumes and densities from the muscle masks segmented by our model and performed correlation analysis with pulmonary function test (PFT) parameters. The segmentation models for muscle tissue and respiratory muscles obtained dice scores of 0.9823 and 0.9688, respectively. The classification model, achieving a generalized dice score of 0.9900, also demonstrated high accuracy in classifying thoracic region muscle types, as evidenced by its F1 scores: 0.9793 for the pectoralis muscle, 0.9975 for the erector spinae muscle, and 0.9839 for the intercostal muscle. In the correlation analysis, the volume of the respiratory muscles showed a strong correlation with PFT parameters, suggesting that respiratory muscle volume may serve as a potential novel biomarker for respiratory function. Although muscle density showed a weaker correlation with the PFT parameters, it has a potential significance in medical research.

Phosphofructokinase family genes in grass carp: Molecular identification and tissue-specific expression in response to glucose, insulin and glucagon.

It is widely acknowledged that glucose serves as the primary energy source for organisms. However, fish exhibit persistent postprandial hyperglycemia and are thought to have low glucose tolerance. Glycolysis serves as the ubiquitous pathway for glucose catabolism, with phosphofructokinase (PFK) acting as a crucial rate-limiting enzyme in this process and playing an indispensable role. PFK is classified into three isoforms based on their major expression sites, i.e., PFKM (skeletal muscle type), PFKL (liver type) and PFKP (platelet type). In this study, grass carp (Ctenopharyngodon idella) was used as animal model and the open reading frame (ORF) sequences of six PFK genetic isoforms of grass carp were cloned. Real-time PCR was used to detect its tissue distribution, and expression changes in oral glucose tolerance test (OGTT), insulin and glucagon injection experiments. The results showed that the ORF of pfkla, pfklb, pfkma, pfkmb, pfkpa and pfkpb genes was 2343, 2340, 2355, 2331, 2364 and 2349bp in length, respectively. The results of tissue distribution showed that pfkla and pfklb, homologous to mammalian pfkl, exhibited low expression levels in the liver of grass carp, but were expressed at the highest level in the brain. Muscle-type pfkma and pfkmb mRNA were found to be highly expressed in both red and white muscle, with pfkmb also exhibiting high expression levels in the heart, while platelet type pfkpa and pfkpb showed high mRNA abundances in the brain and heart. Oral glucose administration stimulated pfkma and pfkmb mRNA expression in the red muscle, and up-regulated pfklb mRNA levels in the liver at 3h post treatment, but it suppressed liver-type and platelet-type PFK genes expression in the brain. The expression of pfkmb in white muscle and pfkmb and pfkpb in heart were promoted by insulin, whereas the expression of pfkla and pfkpb in the brain, pfkma and pfkmb in the red muscle, pfkma in the white muscle, and pfklb in the liver was suppressed by insulin. As for glucagon, it inhibited pfkma and pfkmb mRNA expression in the red muscle, as well as pfklb in the liver, but it up-regulated PFK genes expression in most tissues detected, such as brain (pfklb, pfkpa and pfkpb), white muscle (pfkma and pfkmb), liver (pfkla) and heart (pfkmb and pfkpb). Our results suggest that PFK family genes have different or even opposite expression patterns in response to glucose, insulin and glucagon stimulation in various tissues of grass carp, which may contribute to glucose intolerance in fish.

Unveiling Myasthenia Gravis: A Comprehensive Analysis of Diagnostic Tools and Clinical Insights

Objective: This research offers a comprehensive analysis of Myasthenia Gravis (MG), uncovering the remarkable accuracy of spinal accessory, ulnar, and facial nerve repetitive nerve stimulation (RNS), along with the precision of single fiber electromyography (SF-EMG) in MG diagnosis. We also embark on an exploration of clinical features and autoantibody test results in generalized MG patients.
 Methods: In this prospective study, we welcomed 31 individuals definitively diagnosed with generalized MG into our quest. The categorization of patients was conducted in accordance with the criteria set by the Myasthenia Gravis Foundation of America (MGFA). We examined patients' trapezius, nasalis, and abductor digiti minimi (ADM) muscles using RNS. We meticulously recorded the presence of MG autoantibodies, clinical subtypes based on affected muscle groups, and SF-EMG jitter rates.
 Results: The mean age of the 31 patients of whom 19 (61.3%) were male, was 64 ± 13.9 years. Among them, 20 showed positivity in the Anti-AChR antibody test. In 28 patients, accounting for 90.3% of the study group, single fiber electromyography (EMG) displayed increased jitter. There were 4 (12.9%), 24 (77.4%) and 12 (38.7%) patients featuring a decremental response of exceeding 10% in ADM, trapezius and nasalis muscles, respectivelyOur investigation revealed notable findings, such as the absence of substantial correlations between decremental response rates and age, gender, duration of complaints, antibody test results, thymus abnormalities, affected muscle types, familial history, or increased jitter rates in SF-EMG (p>0.05).
 Conclusion: As our findings clearly show, we can confidently attest to the remarkable sensitivity of RNS in MG diagnosis when muscle selection is precise. A gem discovered on our study is the high sensitivity of the spinal accessory nerve, a revelation that should guide the course of routine RNS studies, particularly for those facing ocular-onset myasthenia.

Sensory innervation of masseter, temporal and lateral pterygoid muscles in common marmosets

Myogenous temporomandibular disorders is associated with an increased responsiveness of nerves innervating the masseter (MM), temporal (TM), and lateral pterygoid muscles (LPM). This study aimed to examine sensory nerve types innervating MM, TM and LPM of adult non-human primate—common marmosets. Sensory nerves were localized in specific regions of these muscles. Pgp9.5, marker for all nerves, and NFH, a marker for A-fibers, showed that masticatory muscles were primarily innervated with A-fibers. The proportion of C- to A-fibers was highest in LPM, and lowest in MM. All C-fibers (pgp9.5+/NFH-) observed in masticatory muscles were peptidergic (CGRP+) and lacked mrgprD and CHRNA3, a silent nociceptive marker. TrpV1 was register in 17% of LPM nerves. All fibers in masticatory muscles were labeled with GFAP+, a myelin sheath marker. There were substantially more peptidergic A-fibers (CGRP+/NFH+) in TM and LPM compared to MM. MM, TM and LPM NFH+ fibers contained different percentages of trkC+ and parvalbumin+, but not trkB+ fibers. Tyrosine hydroxylase antibodies, which did not label TG, highlighted sympathetic fibers around blood vessels of the masticatory muscles. Overall, masticatory muscle types of marmosets have similarities and differences in innervation patterns.

Chemical and fatty acid composition, collagen, calpain and troponin T contents and quality characteristics of five muscle types in native Thai cattle

In this study, chemical composition, fatty acids, collagen solubility, calpains, and troponin T degradation were investigated in various muscles of native Thai cattle (NTC). Five muscles, namely Bicep femoris, Infraspinatus, Longissimus thoracis, Supraspinatus and Semimembranosus were sampled from five Kho Isaan bulls. Moisture content of Longissimus thoracis was lower (p < 0.05) than others. Protein content of Longissimus thoracis, Bicep femoris and Semimembranosus was higher (p < 0.05) than that of Infraspinatus and Supraspinatus. Infraspinatus and Longissimus thoracis had higher fat content (p < 0.05) than Bicep femoris and Semimembranosus. Muscle pH, color, and drip loss did not differ between muscles. Semimembranosus and Supraspinatus showed higher cook loss (p < 0.05) than Infraspinatus and Longissimus thoracis. Infraspinatus had the lowest Warner–Bratzler shear force (p < 0.05). Supraspinatus, Infraspinatus and Bicep femoris had higher (p < 0.05) soluble, insoluble and total collagen content than Semimembranosus and Longissimus thoracis. Infraspinatus had higher collagen solubility than Semimembranosus and Supraspinatus. Collagen content and solubility were not affected by ageing time. The relative band intensities of intact troponin T and its degradation product at 2- and 14-days postmortem were higher in Longissimus thoracis than in other muscles. Infraspinatus and Supraspinatus had significantly higher expression of m-calpain and calpastatin genes than Longissimus thoracis, Bicep femoris, and Semimembranosus. Total fatty acid was higher while the percentage of C22:6n-3 was lower in Infraspinatus and Longissimus thoracis (p < 0.05) than in other muscles. These results show differences in specific nutritional, technological and eating quality characteristics of NTC muscles and thus provide information for optimizing storage and processing conditions for various NTC muscles.

The fatty acid profile and the quality of breast and leg muscles in female and male pearl gray guinea fowl (Numida meleagris)

The aim of this study was to evaluate the fatty acid (FA) profile and the quality of breast and leg muscles in male and female guinea fowl. In comparison with leg muscles, breast muscles had a higher content of dry matter and total protein, and contained less fat and total collagen (P ≤ 0.05). Sex had no effect on the chemical composition of the studied muscles or the FA profile of intramuscular fat (IMF) (P > 0.05). The IMF of breast muscles was characterized by higher proportions of total saturated fatty acids (SFAs) and polyunsaturated fatty acids (PUFAs), and lower proportions of total unsaturated fatty acids (UFAs) and monounsaturated fatty acids (MUFAs) (P ≤ 0.05) than the IMF of leg muscles. The physicochemical properties of guinea fowl meat were significantly influenced by muscle type (P ≤ 0.05), but not by sex (P > 0.05). Leg muscles were characterized by a higher pH, higher cooking loss, lower lightness (L*), lower drip loss, a higher contribution of redness (a*), and a lower contribution of yellowness (b*) than breast muscles (P ≤ 0.05). The experimental factors had no effect on the sensory attributes or the shear force values of the analyzed muscles (P > 0.05). The unique sensory attributes, high protein content, and low fat content of the analyzed muscles indicate that guinea fowl meat can be a dietary supplement and an addition to other types of meat consumed, especially that most guinea fowl are reared in extensive farming systems that contribute to sustainable food production.

The effect of breed and body weight at slaughter on histochemical muscle fiber characteristics and meat quality of longissimus lumborum and semitendinosus lamb muscles

Abstract. The skeletal muscles of mammals are composed of fibers of different morphological, metabolic and functional characteristics. The properties of muscle fibers may be determined genetically as well as by environmental factors such as the age of the animals, their physical activity, the level of nutrition, or the selection intensity. The present study was conducted to determine the influence of genotype (Polish Lowland vs. Polish Heath) and body weight at slaughter (23–25 kg vs. 35–40 kg) of lambs on histological characteristics of muscle fibers in musculus longissimus lumborum (LL) and musculus semitendinosus (ST) skeletal muscles and their impact on chosen meat quality features. Three types of muscle fibers were identified: slow-twitch oxidative (STO), fast-twitch oxidative (FTO) and fast-twitch glycolytic (FTG). Differences in the diameters of individual fiber types between the LL and ST muscles have been found in both investigated genotypes. The diameters of the analyzed types of fibers were usually larger in the ST muscle compared to the LL muscle. The lambs of the more primitive Polish Heath breed were characterized by a smaller diameter of all fiber types, especially in the LL muscle. The higher proportion of STO fibers and the lower proportion of FTO fibers have been found in the LL muscle of Polish Heath lambs in the group with lower body weight. The breed of lambs, muscle type and slaughter body weight had an impact on some meat quality characteristics, especially color, intramuscular fat content and expressed juice.

Effect of Gender and Muscle Type on Fatty Acid Profile, Sanogenic Indices, and Instrumental and Sensory Analysis of Flemish Giant Rabbit Meat

The aim of this study was to represent quality characterization, by gender and muscle type, of rabbit meat from the Flemish Giant (FG) breed, following the fatty acid profile, sanogenic indices, and instrumental (color and texture) and sensory analysis. The biological material comprised 40 rabbits (20 females and 20 males) whose Longissimus dorsi (LD) and Semimembranosus (SM) muscles were sampled. Compared to female samples, the meat from males was more qualitative in terms of higher ratios of polyunsaturated vs. saturated fatty acids and proportions (+42%) of Essential and Desirable Fatty Acids (+21.6% EFA; +6.7% DFA). Also, the Atherogenic Index (AI) and Thrombogenic Index (TI) were better in males (−37.1% AI; −34.3% TI), as were the ratio of hypocholesterolemic/Hypercholesterolemic fatty acids (+27.8%) and the Nutritive Value Index (NVI, +11.6%). The Polyunsaturation Index (PI) was higher for females (+57.5%), with the widest differences in hind leg muscles (SM muscles), while the omega-6/omega-3 fatty acid ratio was also better (+11.3%). Female meat was more tender due to lower shear force (−6.2%… 9.3%) in both muscles. Female meat was less pigmented than that of males, while the overall sensory attributes were better scored in male samples (+3.1%… +7.1%) (p &lt; 0.01). The meat of males proved to be more sanogenic (richer in EFA and DFA, with a better h/H ratio and NVI, while AI and TI were lower). We would recommend slaughtering 3–4 weeks earlier in females vs. males to avoid excessive fat deposition and, consequently, the development of unfavorable sanogenic indices for consumer health.

Does muscle-type myosin have ADPase activity?

Adenosine diphosphate (ADP) is a nucleotide that is structurally very similar to ATP but lacks one of the two high-energy bonds due to hydrolysis. In muscle studies, ADP is usually considered exclusively as a product formed during myosin cross-bridge cycling and is not otherwise involved in this process. In our study, we question the widely held view of ADP as a final product formed during muscle contraction. Using biophysical and biochemical methods, we managed to show that ADP can act as a substrate for myosins in at least three types of muscles: smooth and striated adductor muscles of bivalves (Mytilidae and Pectinidae), and also vertebrate skeletal muscles. According to our data, the differences in the effect of ATP and ADP on the optical, biochemical, and structural properties of actomyosins are exclusively quantitative. We explain the previous ideas about ADP as a compound capable of inhibiting the ATPase activity of actomyosin by the ability of ATP and ADP to depolymerize the polymeric myosin when the concentration in the medium reaches more than 0.3 mM.

Multiscale analysis of Klf10's impact on the passive mechanical properties of murine skeletal muscle

Skeletal muscle is a hierarchical structure composed of multiple organizational scales. A major challenge in the biomechanical evaluation of muscle relates to the difficulty in evaluating the experimental mechanical properties at the different organizational levels of the same tissue. Indeed, the ability to integrate mechanical properties evaluated at various levels will allow for improved assessment of the entire tissue, leading to a better understanding of how changes at each level evolve over time and/or impact tissue function, especially in the case of muscle diseases.Therefore, the purpose of this study was to analyze a genetically engineered mouse model (Klf10 KO: Krüppel-Like Factor 10 knockout) with known skeletal muscle defects to compare the mechanical properties with wild-type (WT) controls at the three main muscle scales: the macroscopic (whole muscle), microscopic (fiber) and submicron (myofibril) levels. Passive mechanical tests (ramp, relaxation) were performed on two types of skeletal muscle (soleus and extensor digitorum longus (EDL)).Results of the present study revealed muscle-type specific behaviors in both genotypes only at the microscopic scale. Interestingly, loss of Klf10 expression resulted in increased passive properties in the soleus but decreased passive properties in the EDL compared to WT controls.At the submicron scale, no changes were observed between WT and Klf10 KO myofibrils for either muscle; these results demonstrate that the passive property differences observed at the microscopic scale (fiber) are not caused by sarcomere intrinsic alterations but instead must originate outside the sarcomeres, likely in the collagen-based extracellular matrix. The macroscopic scale revealed similar passive mechanical properties between WT and Klf10 KO hindlimb muscles.The present study has allowed for a better understanding of the role of Klf10 on the passive mechanical properties of skeletal muscle and has provided reference data to the literature which could be used by the community for muscle multiscale modeling.

Transcription factor support for the dual embryological origin of the sternocleidomastoid and trapezius muscles.

The embryological origin of the trapezius and sternocleidomastoid muscles has been debated for over a century. To shed light on this issue, the present anatomical study was performed. Five fresh frozen human cadavers, three males and two females, were used for this study. Samples from each specimen's trapezius and sternocleidomastoid were fixed in 10% formalin and placed in paraffin blocks. As Paired like homeodomain 2 (Pitx2) and T-box factor 1(Tbx1) have been implicated in the region and muscle type regulation, we performed Tbx1 and Pitx2 Immunohistochemistry (IHC) on these muscle tissue samples to identify the origin of the trapezius and sternocleidomastoid muscles. We have used the latest version of QuPath, v0.4.3, software to quantify the Tbx and Pitx2 staining. For the sternocleidomastoid muscle, for evaluated samples, the average amount of positively stained Tbx1 and Pitx2 was 25% (range 16%-30%) and 18% (range 12%-23%), respectively. For the trapezius muscles, for evaluated samples, the average amount of positively stained Tbx1 and Pitx2 parts of the samples was 17% (range 15%-20%) and 15% (14%-17%), respectively. Our anatomical findings suggest dual origins of both the trapezius and sternocleidomastoid muscles. Additionally, as neither Pitx2 nor Tbx1 made up all the staining observed for each muscle, other contributions to these structures are likely. Future studies with larger samples are now necessary to confirm these findings.

Ginsenoside Rb1 induces hepatic stellate cell ferroptosis to alleviate liver fibrosis via the BECN1/SLC7A11 axis

Liver fibrosis is primarily driven by the activation of hepatic stellate cells (HSCs), a process associated with ferroptosis. Ginsenoside Rb1 (GRb1), a major active component extracted from Panax ginseng, inhibits HSC activation. However, the potential role of GRb1 in mediating HSC ferroptosis remains unclear. This study examined the effect of GRb1 on liver fibrosis both in vivo and in vitro, using CCl4-induced liver fibrosis mouse model and primary HSCs, LX-2 cells. The findings revealed that GRb1 effectively inactivated HSCs in vitro, reducing alpha-smooth muscle actin (α-SMA) and type I collagen (Col1A1) levels. Moreover, GRb1 significantly alleviated CCl4-induced liver fibrosis in vivo. From a mechanistic standpoint, the ferroptosis pathway appeared to be central to the antifibrotic effects of GRb1. Specifically, GRb1 promoted HSC ferroptosis both in vivo and in vitro, characterized by increased glutathione depletion, malondialdehyde production, iron overload, and accumulation of reactive oxygen species (ROS). Intriguingly, GRb1 increased Beclin 1 (BECN1) levels and decreased the System Xc-key subunit SLC7A11. Further experiments showed that BECN1 silencing inhibited GRb1-induced effects on HSC ferroptosis and mitigated the reduction of SLC7A11 caused by GRb1. Moreover, BECN1 could directly interact with SLC7A11, initiating HSC ferroptosis. In conclusion, the suppression of BECN1 counteracted the effects of GRb1 on HSC inactivation both in vivo and in vitro. Overall, this study highlights the novel role of GRb1 in inducing HSC ferroptosis and promoting HSC inactivation, at least partly through its modulation of BECN1 and SLC7A11.

Corylin Attenuates CCl4-Induced Liver Fibrosis in Mice by Regulating the GAS6/AXL Signaling Pathway in Hepatic Stellate Cells.

Liver fibrosis is reversible when treated in its early stages and when liver inflammatory factors are inhibited. Limited studies have investigated the therapeutic effects of corylin, a flavonoid extracted from Psoralea corylifolia L. (Fabaceae), on liver fibrosis. Therefore, we evaluated the anti-inflammatory activity of corylin and investigated its efficacy and mechanism of action in ameliorating liver fibrosis. Corylin significantly inhibited inflammatory responses by inhibiting the activation of mitogen-activated protein kinase signaling pathways and the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha in human THP-1 and mouse RAW264.7 macrophages. Furthermore, corylin inhibited the expression of growth arrest-specific gene 6 in human hepatic stellate cells (HSCs) and the activation of the downstream phosphoinositide 3-kinase/protein kinase B pathway. This inhibited the activation of HSCs and the expression of extracellular matrix proteins, including α-smooth muscle actin and type I collagen. Additionally, corylin induced caspase 9 and caspase 3 activation, which promoted apoptosis in HSCs. Moreover, in vivo experiments confirmed the regulatory effects of corylin on these proteins, and corylin alleviated the symptoms of carbon tetrachloride-induced liver fibrosis in mice. These findings revealed that corylin has anti-inflammatory activity and inhibits HSC activation; thus, it presents as a potential adjuvant in the treatment of liver fibrosis.

Esophageal anatomy and physiology vary across spastic and non-spastic phenotypes of disorders of esophagogastric junction outflow.

Pathophysiologic mechanisms of disorders of esophagogastric junction (EGJ) outflow are poorly understood. We aimed to compare anatomic and physiologic characteristics among patients with disorders of EGJ outflow and normal motility. We retrospectively evaluated adult patients with achalasia types 1, 2, 3, EGJ outflow obstruction (EGJOO) or normal motility on high-resolution manometry who underwent endoscopic ultrasound (EUS) from January 2019 to August 2022. Thickened circular muscle was defined as ≥1.6 mm. Characteristics from barium esophagram (BE) and functional lumen imaging probe (FLIP) were additionally assessed. Of 71 patients (mean age 56.2 years; 49% male), there were 8 (11%) normal motility, 58 (82%) had achalasia (5 (7%) type 1, 32 (45%) classic type 2, 21 (30%) type 3 [including 12 type 2 with FEPs]), and 7 (7%) had EGJOO. A significantly greater proportion of type 3 achalasia had thickened distal circular muscle (76.2%) versus normal motility (0%; p < 0.001) or type 2 achalasia (25%; p < 0.001). Type 1 achalasia had significantly wider mean maximum esophageal diameter on BE (57.8 mm) compared to type 2 achalasia (32.8 mm), type 3 achalasia (23.4 mm), EGJOO (15.9 mm), and normal motility (13.5 mm). 100% type 3 achalasia versus 0% type 1 achalasia/normal motility had tertiary contractions on BE. Mean EGJ distensibility index on FLIP was lower for type 3 achalasia (1.2 mmHg/mm2 ) and EGJOO (1.2 mmHg/mm2 ) versus type 2 (2.3 mmHg/mm2 ) and type 1 achalasia (2.9 mmHg/mm2 ). Our findings suggest distinct pathologic pathways may exist: type 3 achalasia and EGJOO may represent a spastic outflow phenotype consisting of a thickened, spastic circular muscle, which is distinct from type 1 and 2 achalasia consisting of a thin caliber circular muscle layer with more prominent esophageal dilation.

Correlation between Biogenic Amines and Their Precursors in Stored Chicken Meat

Biogenic amines (BAs) are biologically active substances found in the cells of microorganisms, plants, and animals. These BAs serve many vital functions in the body. However, an excessive amount can be toxic, especially for individuals taking monoamine oxidase (MAO) and diamine oxidase (DAO) inhibitors. They primarily form in products rich in amino acids, the primary substrates for BA formation. The aim of this study was to determine the formation of BAs and their precursor amino acids in chicken breast and leg muscles stored under chilling conditions. Analyses of BA and AA determinations were conducted on days 1, 3, 5, 7, and 10 of muscle storage. There was a noted increase in BAs with the storage of both muscle types (p &lt; 0.05). Distinct levels of BAs were detected (p &lt; 0.05) in the muscles, except for putrescine (p &gt; 0.05). Interactions emerged between the two factors for various Bas, including histamine (p = 0.001), tyramine (p &lt; 0.001), BAI index (p &lt; 0.001), tryptamine (p &lt; 0.001), agmatine (p = 0.001), spermidine (p &lt; 0.001), TOTAL BA-1 (p &lt; 0.001), and TOTAL BA-2 (p = 0.016). There was no evident interaction between the type of meat and storage time concerning amino acid content (p &gt; 0.05). Correlations in breast muscles were observed for biogenic amine–amino acid pairs such as putrescine–ornithine (r = −0.57) (p &lt; 0.05), spermidine–ornithine (r = −0.73) (p &lt; 0.05), and phenylethylamine–phenylethylalanine (r = −0.50) (p &lt; 0.05). In leg muscles, significant correlations were found for histamine–histidine (r = −0.87) (p &lt; 0.05), putrescine–ornithine (r = −0.96) (p &lt; 0.05), and phenylethylamine–phenylethylalanine (r = −0.65) (p &lt; 0.05). The results obtained can be used in the future to estimate the levels of BAs with knowledge of the levels of individual amino acids and inversely.

Novel Technology Allowing Cone Beam Computed Tomography in 6 Seconds: A Patient Study of Comparative Image Quality

PurposeThe goal of this study was to evaluate the image quality provided by a novel cone beam CT (CBCT) platform (HyperSightTM, Varian Medical Systems), a platform with enhanced reconstruction algorithms as well as rapid acquisition times. Image quality was compared to both status quo CBCT for image guidance, and to fan beam CT (FBCT) acquired on a CT simulator (CTsim). MethodsIn a clinical study, 30 subjects were recruited for whom either deep inspiration (DIBH) or deep exhalation breath hold (DEBH) was used during imaging and radiation treatment of tumors involving liver, lung, breast, abdomen, chest wall and pancreatic sites. All subjects were imaged during breath hold with CBCT on a standard image guidance platform (TrueBeam® 2.7, Varian Medical Systems) and FBCT CT (CTsim, GE Optima). HyperSight imaging with both breath hold (HSBH) and free breathing (HSFB) was performed in a single session. The four image sets thus acquired were registered and compared using metrics quantifying artifact index (AI), image non-uniformity, contrast, contrast-to-noise ratio (CNR), and difference of HU from CTsim. ResultsHSBH provided less severe artifacts compared to both HSFB and TrueBeam. The severity of artifacts in HSBH images was similar to that in CTsim images, with statistically similar AI values. CTsim provided the best image uniformity, however HSBH provided improved uniformity compared to both HSFB and TrueBeam. CTsim demonstrated elevated contrast compared to HyperSight imaging, but both HSBH and HSFB imaging showed superior CNR characteristics compared to TrueBeam. The median HU difference of HSBH from CTsim was within 1 HU for muscle/fat tissue, 12 HU for bone and 14 HU for lung. ConclusionThe HyperSight system provides six-second CBCT acquisition with image artifacts that are significantly reduced compared to TrueBeam and comparable to those in CTsim FBCT imaging. HyperSight breath hold imaging was of higher quality compared to free breathing imaging on the same system. The median HU value in HyperSight breath hold imaging is within 15 HU of that in CT simulation imaging for muscle, fat, bone and lung tissue types, indicating the utility of image data for direct dose calculation in adaptive workflows.

248 Divergent Satellite Cell Profiles of Bovine Trapezius, Longissimus, and Bicep Femoris Muscles in Utero

Abstract As we look to better understand whole body growth and development, there are still many mechanisms of individual muscle growth that we have yet to comprehend. Therefore, the objective of this study was to compare proliferative capacity and satellite cell number within the trapezius (TP), longissimus (LM), and bicep femoris (BF) muscles of fetal bovine throughout mid and late gestation. We hypothesized a difference in satellite cell number across these three muscles may further explain the differential growth pattern of each of these muscles in utero. Muscle samples were harvested from bovine fetuses at a commercial abattoir and aged using crown rump length (~150-220d in utero). These samples were then dissected into single fibers and seeded in a 3D hydrogel culture with 20% FBS media. Cells were fixed using 4% paraformaldehyde and stained for DAPI, Pax-7, Myf-5 (Invitrogen, Bedford, MA) at 72, 96, and 120h. Wells were imaged and analyzed for proliferation rate using the Cytation 5 (Agilent; La Jolla, CA) Prime Gen 5 software. Data were analyzed as a two-way ANOVA with repeated measures using GraphPad Prism (Version 9.5). For Myf-5, Pax-7, and dual positive cells (P ≤ 0.05) there was a difference across muscle type with BF having an increased number of positive cells compared with the TP muscle and LM being intermediate (Myf-5 mean = 51, 23, and 40 respectively; Pax-7 mean = 45, 30, and 20 respectively; Dual mean = 39, 20, 16 respectively). This variation was further supported by a similar divergence in proliferation rate across muscle type (P = 0.04), with BF muscle having increased proliferative capacity over TP muscle and LM muscle being intermediary. These findings suggest contrasting growth patterns across muscle types in utero that may influence postnatal growth patterns. Further research is needed to understand how the variability in satellite cell number contributes to differences in individual muscle growth.

PSVII-22 Effect of Trimming External Fat Before Cooking on Palatability and Calorie Content of Beef Ribeye Steaks

Abstract Consumer concerns about excess dietary fat have increased the practice of removing external fat from beef steaks prior to cooking. This practice, however, may be detrimental to meat eating quality. The objective of this study was to determine the effects of removing the external fat before cooking on the eating quality and calorie content of ribeye steaks. Twenty longissimus thoracis muscles with Canada AAA (n = 10) and AA (n = 10) quality grades (equivalent to USDA Choice and Select, respectively) were obtained from a federally inspected commercial slaughter plant, vacuum packaged and transported under refrigerated conditions to the Lacombe Research and Development Centre (Agriculture and Agri-Food Canada). After an average of 28 d of ageing, the muscles were removed from the vacuum packaging and fabricated into four 2.54-cm steaks. One-half of the steaks were trimmed to 0.635 cm of external fat (cap on). The remaining steaks were completely trimmed of external and seam (kernel) fats (cap off), and the longissimus and spinalis dorsi muscles were combined with butcher’s twine. Steaks were cooked on an electric grill to an endpoint temperature of 74 °C. Subsequently, descriptive sensory analyses were performed by a 10-member trained meat evaluation panel and calorie analyses were conducted. Results: Compared with muscles of AA steaks cooked with cap off, the AA steaks cooked with cap on had longissimus with greater initial and sustained juiciness (P &amp;lt; 0.01) and a tendency towards a smaller proportion of panelists detecting livery off-flavor (P = 0.058) and mealy texture (P = 0.071), and spinalis with a tendency towards fewer panelists detecting unidentified off-flavors (P = 0.096) and spongy texture (P = 0.096). When cooking the AAA steaks with cap on, the longissimus had a decreased frequency of panelists detecting ‘other’ off-flavors (i.e., burnt, rancid, barnyard, stale; P &amp;lt; 0.05) and mushy texture (P &amp;lt; 0.05) and tended to have less off-flavor intensities (P = 0.083), whereas the spinalis had greater beef flavor intensity and desirability (P &amp;lt; 0.05) and fewer panelists tending to detect ‘other’ off-flavors (i.e., burnt, fatty, oily, rancid; P = 0.052), compared with steaks cooked with cap off. The more pronounced flavor effects in the spinalis compared with the longissimus of AAA steaks cooked with cap on could be due to the spinalis having greater endpoint temperatures than the longissimus muscles, which probably caused more Maillard reactions and more efficient fat melting. Regardless of the quality grade and muscle type, cooking steaks with cap on did not increase the calorie content (P &amp;gt; 0.10). Overall, cooking ribeye steaks with external fat had positive effects on juiciness, flavor and texture without increasing the calorie content compared with steaks cooked without external fat. Educating consumers on the benefits of maintaining the external fat while cooking will improve the eating experience of Canadian beef.