Intermediate Muscles Research Articles

Quantitative Muscle Analysis in FSHD Using Whole-Body Fat-Referenced MRI: Composite Scores for Longitudinal and Cross-sectional Analysis.

Facioscapulohumeral muscular dystrophy (FSHD) is a rare, debilitating disease characterized by progressive muscle weakness. MRI is a sensitive assessment of disease severity and progression. We developed a quantitative whole-body (WB) musculoskeletal MRI (WB-MSK-MRI) protocol analyzing muscles in their entirety. This study aimed to assess WB-MSK-MRI as a potential imaging biomarker providing reliable measurements of muscle health that capture disease heterogeneity and clinically meaningful composite assessments correlating with severity and more responsive to change in clinical trials. Participants aged 18-65 years, with genetically confirmed FSHD1, clinical severity 2 to 4 (Ricci scale, range 0-5), and ≥1 short tau inversion recovery-positive lower extremity muscle eligible for needle biopsy, enrolled at 6 sites and were imaged twice 4-12 weeks apart. Volumetric analysis of muscle fat infiltration (MFI), muscle fat fraction (MFF), and lean muscle volume (LMV) in 18 (36 total) muscles from bilateral shoulder, proximal arm, trunk, and legs was performed after automated atlas-based segmentation, followed by manual verification. A WB composite score, including muscles at highest risk for progression, and functional cross-sectional composites for correlation with relevant functional outcomes including timed up and go (TUG), FSHD-TUG, and reachable workspace (RWS), were developed. Seventeen participants enrolled in this study; 16 follow-up MRIs were performed at 52 days (range 36-85 days). Functional cross-sectional composites (MFF and MFI) showed moderate to strong correlations: TUG (ρ = 0.71, ρ = 0.83), FSHD-TUG (ρ = 0.73, ρ = 0.73), and RWS (left arm: ρ = -0.71, ρ = -0.53; right arm: ρ = -0.61, ρ = -0.65). WB composite variability: LMVtot, coefficient of variation (CV) 1.9% and 3.4%; MFFtot, within-subject SD (Sw) 0.5% and 1.5%; and MFItot (Sw), 0.3% and 0.4% for normal and intermediate muscles, respectively. CV and Sw were higher in intermediate (MFI ≥0.10; MFF <0.50) than in normal (MFI <0.10, MFF <0.50) muscles. We developed a WB-MSK-MRI protocol and composite measures that capture disease heterogeneity and assess muscle involvement as it correlates with FSHD-relevant clinical endpoints. Functional composites robustly correlate with functional assessments. Stability of the WB composite shows that it could be an assessment of change in therapeutic clinical trials. This study provides Class II evidence that quantitative WB-MSK-MRI findings associate with FSHD1 severity measured using established functional assessments.

Grasping behavior in the white‐tailed sea eagle (Accipitridae, Aves) explained by muscle architecture

AbstractHindlimbs of raptors play an essential role in feeding due to the grasping abilities that allow them to hunt and kill their prey. This study explores and quantifies for the first time the structural and mechanical features of the digit flexor muscles in one of the largest piscivorous European raptors, the white‐tailed sea eagle. We studied the myological architecture of nine muscles of five females and five males of Haliaeetus albicilla. We found that (1) reversed sexual dimorphism was not reflected in any of these structural or mechanical variables; (2) when the physiological cross‐sectional area values of muscles were scaled altogether against body mass, they had a positive allometric tendency, implying that larger muscles have proportionally higher physiological cross‐sectional area values than smaller ones. Conversely, different scaling patterns were obtained when each flexor was analyzed individually: Only three muscles were positively allometric, and four muscles were isometric. (3) Three major groups can be identified in relation to the different features here analyzed: (1) flexor digitorum longus, flexor hallucis longus and tibialis cranialis: large muscles, with high physiological cross‐sectional area and tendon cross‐sectional area, low tendon/belly ratio and isometric; (2) flexor hallucis brevis: small muscle, with intermediate physiological cross‐sectional area and tendon cross‐sectional area, low tendon/belly ratio, short fiber length and isometric; (3) musculi perforans and perforans et perforatus: intermediate muscles, with low physiological cross‐sectional area and tendon cross‐sectional area, high tendon/belly ratio and allometric. Haliaeetus albicilla hunts mainly fish, an elusive prey, and their muscles have an anatomical design related to their common purpose, to grip prey. However, different patterns that characterize each muscle might respond to different requirements related to this particular prey item and hunting behavior and to the role each digit can perform.

The effects of hot boning on meat quality from six different contractile‐metabolic sheep muscles: A preliminary study

We evaluated the effect of hot boning on meat quality from six different contractile-metabolic sheep muscles. Nine heavy-lambs were slaughtered and divided in two experimental groups: Cold boned carcasses (CBC; N = 5), and Hot boned carcasses (HBC; N = 4). CBC were conventionally cooled for 24 hr at 4°C before muscle dissection while muscles from HBC were dissected immediately after slaughter and individually cooled for 24 hr at 4°C. Meat from HBC showed higher water-holding capacity, shorter sarcomeres, higher shear forces, higher hue* values, and lower tenderness rankings. Hot boning increased water-holding capacity in slow-oxidative muscles and increased cooking losses in fast-glycolytic muscles. Hot boning reduced sarcomere length in slow-oxidative muscles, and increased shear force in slow-oxidative and intermediate muscles. Our results contribute to the knowledge of how hot boning impacts on meat quality indicating that hot boning affects meat quality, but these effects vary between different types of muscles. Practical applications The present study demonstrated that hot boning affects sheep meat quality, but these effects vary between different types of muscles. Faster and more glycolytic muscles are less susceptible to sarcomere shortening and meat toughening when hot boned. Also, our results suggest that the beneficial effects of hot boning on water-holding capacity are mainly evidenced in slower and more oxidative muscles. Therefore, our study may serve as preliminary evidence of how a partial hot boning system (removing only some selected carcass muscles prior to the onset of rigor mortis) could imply enhanced industrial efficiency for sheep meat processors by decreasing energy and labor costs associated with chilling and boning but minimizing the impact on meat quality.

Fatty acid and lipid contents differentiation in cuts of rabbit meat

ABSTRACTThe study aimed at quantifying fatty acids (FA), especially the health-promoting ones, in cuts of rabbit meat. Loin, containing mostly glycolytic muscles, had less lipids than cuts containing oxidative (hind leg) or intermediate muscles (foreleg and brisket). Brisket had the highest polyunsaturated FA (PUFA), odd- and branched-chain FAs (OBCFA) and palmitoleic acid C16:1 n-7 contents, better n-6/n-3 proportion, advantageous nutritional indexes (AI, TI, H/H) than other cuts. Hind leg contained less atherogenic saturated FAs (LCSFA) than other cuts. Foreleg was rich in two important n-3 LC-PUFAs: C20:5 and C22:5. The results suggest that apart from the preferred cuts (loin and hind leg) used in gastronomy, brisket and foreleg should be included for being rich in nutritionally valuable PUFA, especially from the n-3 family. Daily portion (250 g) of foreleg would cover 16% of the requirement for EPA and DHA, and the same amount of brisket or hind leg—11%.

Variation in instrumental meat quality among 15 muscles from 14-month-old sheep and its relationship with fibre typing

The aims of the present study were to describe intermuscular differences in meat-quality traits in 15 young-sheep muscles, and to study the associations between meat quality and fibre typing across all (pooled) muscles as well as in previously selected homogeneous contractile–metabolic groups of muscles (slow-oxidative, intermediate and fast-glycolytic muscles). Meat-quality traits (pH, colour, expressed juice, cooking losses, tenderness and sarcomere length) and fibre typing were evaluated after 24 h of slaughter in 15 muscles from five cross-bred young sheep. Across all the studied muscles, intermuscular differences in some meat-quality traits (pH24, a* and expressed juice) seemed to be mainly explained by muscle oxidative activity, while intermuscular variation in other meat-quality traits (L*, b* and Warner–Bratzler shear force) were mainly explained by differences in fibre sizes. Within fast-glycolytic muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, lower a* values and longer sarcomeres. Within intermediate muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower ultimate pH, higher L* values, shorter sarcomeres and reduced meat tenderness. Within slow-oxidative muscles, larger fast-glycolytic fibres and reduced oxidative activity were generally associated with lower amounts of expressed juice, lower a* values and reduced meat tenderness. The present study has contributed to a better understanding of the influence of muscle fibre types on intermuscular meat-quality variation, suggesting that although muscle fibre diversity may explain, at least in part, intermuscular differences in meat quality, these associations can also slightly vary among muscle contractile–metabolic groups.

Contributions of Muscles of Various Color Stabilities to the Overall Color Stability of Ground Beef

Ground high (HCS), intermediate (ICS), and low color stability (LCS) cow muscles were used to investigate effects of blending muscles of different color stabilities on ground beef display color. Six formulations at 90% and 80% lean points combining HCS, ICS, and LCS muscles were: 50% HCS + 50% ICS; 50% HCS + 50% LCS; 50% ICS + 50% LCS; 33.3% HCS + 33.3% ICS + 33.3% LCS; 75% HCS + 25% LCS; and 25% HCS + 75% LCS. Patties were packaged in a high oxygen (80% O(2), 20% CO(2)) modified atmosphere, held in dark storage for 5 d, then displayed for 4 d. The 80% lean patties containing >or= 50% HCS had the brightest red initial visual color. During display 75% HCS + 25% LCS at both lean points had the most cherry-red display color. Patties containing a greater proportion of HCS had greater metmyoglobin reducing ability throughout display. HCS, ICS, and LCS muscle can be mixed without adverse color affects, provided LCS muscle is <or= 25%, and HCS muscle is >or= 50% of the blend.

Seasonal variation in sonic muscles in the fawn cusk-eelLepophidium profundorum

The fawn cusk-eel Lepophidium profundorum (Ophidiidae) has an unusual sound-producing system with sexually dimorphic sets of antagonistic muscles. Outside the mating season, the dorsal and ventral muscles are well developed and larger in males than in females, but the tiny intermediate muscles are smaller, suggesting a minor role, if any, in male advertisement call production. We examined summer individuals with more developed gonads and find a fourfold hypertrophy of the intermediate but not the other muscles. This result suggests androgen dependence and an important role in sound production for the intermediate muscle. Even though both sexes gain weight in the summer, the ventral and dorsal muscles in females lose weight, suggesting that sound production is less important in females and that muscle mass may be used to support egg growth.

Contents of creatine, creatinine and carnosine in porcine muscles of different metabolic types

Creatine, creatinine and carnosine have been analyzed by hydrophilic interaction chromatography (HILIC) in seven different pork muscles of different metabolic type ( Semimembranosus, Biceps femoris, Gluteus maximus, Longissimus dorsi, Gluteus medius, Trapezius and Masseter). As reported in previous literature, carnosine contents are related with the type of metabolism, being higher in those muscles with glycolytic metabolism. Creatine and creatinine also showed significantly higher concentrations in glycolytic muscles such as Semimembranosus, Biceps femoris, Gluteus maximus and Longissimus dorsi. Masseter, a red oxidative muscle, was characterized by the lowest contents of creatine, creatinine and carnosine and, finally, Gluteus medius and Trapezius, both intermediate muscles, had also intermediate contents of these studied compounds. Finally, a correlation between initial content of creatine and creatinine formation after cooking has been verified using pure standards and two different metabolic type muscles, Longissimus dorsi and Masseter, obtaining slightly higher creatinine amounts in Longissimus dorsi, probably due to its higher initial creatine content and its lower pH.

Functional morphology of the sonic apparatus in the fawn cusk‐eel Lepophidium profundorum (Gill, 1863)

Recent reports of high frequency sound production by cusk-eels cannot be explained adequately by known mechanisms, i.e., a forced response driven by fast sonic muscles on the swimbladder. Time to complete a contraction-relaxation cycle places a ceiling on frequency and is unlikely to explain sounds with dominant frequencies above 1 kHz. We investigated sonic morphology in the fawn cusk-eel Lepophidium profundorum to determine morphology potentially associated with high frequency sound production and quantified development and sexual dimorphism of sonic structures. Unlike other sonic systems in fishes in which muscle relaxation is caused by internal pressure or swimbladder elasticity, this system utilizes antagonistic pairs of muscles: ventral and intermediate muscles pull the winglike process and swimbladder forward and pivot the neural arch (neural rocker) above the first vertebra backward. This action stretches a fenestra in the swimbladder wall and imparts strain energy to epineural ribs, tendons and ligaments connected to the anterior swimbladder. Relatively short antagonistic dorsal and dorsomedial muscles pull on the neural rocker, releasing strain energy, and use a lever advantage to restore the winglike process and swimbladder to their resting position. Sonic components grow isometrically and are typically larger in males although the tiny intermediate muscles are larger in females. Although external morphology is relatively conservative in ophidiids, sonic morphology is extremely variable within the family.

Functional morphology of the sonic apparatus in Ophidion barbatum (Teleostei, Ophidiidae)

Most soniferous fishes producing sounds with their swimbladder utilize relatively simple mechanisms: contraction and relaxation of a unique pair of sonic muscles cause rapid movements of the swimbladder resulting in sound production. Here we describe the sonic mechanism for Ophidion barbatum, which includes three pairs of sonic muscles, highly transformed vertebral centra and ribs, a neural arch that pivots and a swimbladder whose anterior end is modified into a bony structure, the rocker bone. The ventral and intermediate muscles cause the rocker bone to swivel inward, compressing the swimbladder, and this action is antagonized by the dorsal muscle. Unlike other sonic systems in which the muscle contraction rate determines sound fundamental frequency, we hypothesize that slow contraction of these antagonistic muscles produces a series of cycles of swimbladder vibration.

Distribution of α-tocopherol in beef muscles following dietary α-tocopheryl acetate supplementation

The objective of this study was to determine the effect of dietary vitamin E supplementation on the distribution and concentration of α-tocopherol in beef muscles. Crossbred cattle ( n=8) were selected and divided into two groups and fed diets containing 20 (basal) and 3000 mg (supplemented) α-tocopheryl acetate/head/day for 135 days prior to slaughter. Carcasses were split centrally and chilled at 4°C for 10 days. Muscles ( n=16) were identified and removed from the left side of each animal and stored at −20°C until required. Mean α-tocopherol levels in muscles were significantly ( P<0.05) higher in all supplemented muscles with the exception of m. infraspinatis and m. deltoidous compared to controls. Mean α-tocopherol levels in muscles from the supplemented group decreased in the order m. supraspinatis > m. psoas major > m. trapezius > m. gluteus medius > m. triceps caput brachii lumborum > m. rhomboidous > m. seratus ventralis > m. gluteobiceps > m. semitendinosus > m. semimembranosus > m. infraspinatis > m. subscapularis > m. tricepscaputbrachiilaterale > m. deltoidous > m. longissimus thorasis > m. longissimus lumborum. Significant ( P<0.05) differences in α-tocopherol distribution within muscles were observed for supplemented m. psoas major and control m. seratus ventralis (highest levels in posterior ends and lowest in anterior ends) only. However, trends showed definite distribution patterns for other muscles. Levels of α-tocopherol were found to be highest in oxidative muscles ( m. psoas major and m. gluteus medius) and lowest in glycolytic muscles ( m. longissimus thoracis and m. longissimus lumborum) while moderate levels of α-tocopherol occurred in intermediate muscles ( m. semimembranosus).

Lipid composition and lipolytic enzyme activities in porcine skeletal muscles with different oxidative pattern

Three muscles with different oxidative pattern ( m. longissimus dorsi, Ld; m. biceps femoris, Bf; m. triceps brachii, Tb) have been analysed for lipid composition and lipolytic activities. The results showed a relatively low lipid (around 30 g kg −1) and cholesterol (around 0.5 g kg −1) content being higher in the oxidative and intermediate muscles Tb and Bf, respectively, than in Ld. Muscle Tb had higher amount of phospholipids and PUFA. Muscle Tb also had the higher lipolytic activity (acid and neutral lipase and acid phospholipase activities). There were no differences for acid and neutral esterase activities between the three muscles studied. The use of principal component (PC) analysis might be used to distinguish among the three studied muscles since each one showed a different pattern based on the lipid composition and lipolytic activities.

Appearance and some neurochemical features of nitrergic neurons in the developing quail digestive tract.

Using immunocytochemistry, NADPH-diaphorase (NADPHd) histochemistry and electron microscopy, the appearance of nitrergic enteric neurons in different digestive tract regions of the embryonic, neonatal and adult quail was studied in whole mounts and sections. NADPHd was first expressed by embryonic day 4-5 in two distinct locations, namely the mesenchyme of the gizzard primordium and at the caeco-colonic junction. At embryonic day 6, nitrergic neurons had already begun to form a myenteric nerve network in the wall of the proventriculus, gizzard and proximal part of the large intestine and by embryonic day 9, a myenteric network was visualized along the entire digestive tract of the quail. At the level of the stomach, this network was confined to the area covered by the intermediate muscles. By embryonic day 12-13, the NADPHd-positive myenteric neurons in the wall of the distal parts of the blind-ending paired caeca also became organized into ganglia. From this developmental stage on, a submucous nitrergic nerve network, sandwiched between the lamina muscularis mucosae and the luminal side of the outer muscle layer, became prominent in the proventriculus and intestinal walls. In the adult quail, only a minority of the NADPHd-positive neurons stained for vasoactive intestinal polypeptide (VIP) along the intestine. VIP-immunoreactive (IR) cell bodies were frequent in the myenteric plexus but not in the submucous plexus, whereas there were considerable numbers of NADPHd-positive neurons in both these plexuses. Nitrergic fibres were also observed in the outer muscle layer, but were almost absent from the lamina muscularis mucosa and lamina propria, in contrast to the dense VIP-ergic innervation encircling the bases of the intestinal crypts.

Pathfinding in the central nervous system and periphery by identified embryonic Drosophila motor axons

We have studied the pattern of axon outgrowth from the identified embryonic Drosophila motorneurons, RP1, RP3, RP4 and RP5, from the onset of axonogenesis to the time of arborization over target muscles. Lucifer Yellow was intracellularly injected into each of these neurons to obtain a detailed description of the morphology of their growth cones and of the pathways that they follow. We have divided the sequence of axon growth from these neurons into five major phases. In the first phase, the growth cone of each RP axon grows medially along its contralateral homologue along the anterior commissure. Each RP axon follows a separate path across the midline in the anterior commissure. After crossing the ventral midline, the axons wrap around specific contralateral RP somata. In the second phase, each axon grows posteriorly and dorsally down the contralateral longitudinal connective, fasciculating with the other RP axons. In the third phase, the axons turn into the intersegmental nerve via the anterior nerve root, then cross over to the segmental nerve, before contacting the external surfaces of intermediate muscles 15/16. They do not fasciculate with the pioneering aCC and RP2 axons at this time. In the fourth phase, the axons advance laterally across the ventral muscle group. During this phase, each axon extends processes over a number of inappropriate muscles as well as contacting its correct, target muscle. In the final phase, the processes to inappropriate muscles are withdrawn, generating the mature pattern of motor axon projections. There is no consistent, clear difference between the RP motorneurons in the relative timing of axon outgrowth.

Topography and nerve supply of the cucullaris (trapezius) of skates

Dissections of Sudan black B stained specimens reveal that, of a complex of medial, intermediate, and lateral muscles of skates, presumed homologous to the cucullaris of sharks, only the lateral muscle is innervated by a branch or branches of the vagus and is inserted, in part, to the fused pharyngobranchials of the caudal visceral arches. The medial and intermediate muscles are supplied by separate branches of rostral spinal nerves and do not attach to the branchial skeleton. The lateral muscle therefore is the most likely homologue of the cucullaris (trapezius) of sharks and perhaps other fishes and tetrapods. The medial and intermediate muscles appear to be part of the axial musculature.

Denervation in hemiplegic muscles.

This study examined the frequency of denervation activity in hemiplegic muscles in relation to the size and location of the central lesion. We studied 20 patients, 14 with major unilateral cerebral infarctions in the middle cerebral or internal carotid territories; four with a single lacune in the pons, internal capsule, or thalamus; and two with precentral infarcts. Using somatosensory evoked potentials, motor conduction studies, and assessments of conduction across the plexus and roots, we detected no conduction abnormalities on the affected side. Fibrillation was common in both groups, especially in distal and intermediate muscles. The distribution of the fibrillation and the normal conduction studies suggested that trauma of peripheral nerves was not a factor. Although the normal conduction studies and pattern of fibrillation activity do not exclude peripheral nerve trauma as the cause of the fibrillation, we suggest that transsynaptic degeneration is a reasonable alternative explanation.

Histochemical Mapping and Fiber Size Analysis of Mimic Muscles

Fourteen functionally relevant mimic muscles of nine human bodies were analyzed with respect to their muscle fiber sizes and their histochemical fiber type composition. In cryostat sections stained for actomyosin ATPase, type 1 and type 2 fibers were evaluated separately by means of computer-assisted image analysis. The fiber diameters varied between 20.24 and 41.45 microns. According to the proportions of the fiber types, the mimic muscles could be classified into three groups: (1) phasic muscles, with 14 to 15 percent type 1 fibers, (2) intermediate muscles, with 28 to 37 percent type 1 fibers, and (3) tonic muscles, containing 41 to 67 percent type 1 fibers. It is concluded that one has to consider this diversity of mimic muscles when planning the surgical reconstruction of facial paralysis.

Arterial supply to the masseter muscle in the cow.

Dissection of the cows injected with red-colored starch or latex revealed that the arteries which supplied the masseter muscle were the facial, external carotid, transverse facial, masseteric, and buccal arteries. The subdivided muscles of the masseter muscle received such various arteries and their branches, in the following manners. 1) The first and second superficial and intermediate masseter muscles received the masseteric branches from the facial and external carotid arteries as well as the transverse facial, masseteric, and buccal arteries. 2) The pars anterior of the deep masseter muscle received only the masseteric artery. 3) The pars posterior of the deep masseter muscle received the masseteric and transverse facial arteries. 4) The precursory layer of the maxillomandibular muscle received the masseteric, buccal, and transverse facial arteries. 5) The first and second layers of the maxillomandibular muscle and the zygomaticomandibular muscle received the buccal and masseteric arteries.

Exercise-induced changes of reactivity of different types of muscle on glycogenolytic effect of adrenaline.

In the investigations presented it was found that the glycogenolytic effect of adrenaline in the skeletal muscle of resting rats depends on the type of muscle: the hormone exerts the least effect in the white muscle and the greatest effect in the intermediate one. There was a cumulative effect of adrenaline in a dose of 0.1 mg/kg and exercise on the glycogen level in the white muscle. In the red and intermediate muscles the exercise-induced glycogen depletion rate was very rapid and no additional effect of adrenaline on glycogen level was observed. No repletion of glycogen in the white muscle occurred during the first 3 h of the post-exercise recovery, and adrenaline further decreased the glycogen level in this muscle. In the red and intermediate muscles full repletion of glycogen took place already during the first hour of recovery. A dose of 0.1 mg/kg adrenaline had no effect on the glycogen repletion rate in the red muscle and only partly inhibited it in the intermediate muscle. A dose of 0.5 mg/kg adrenaline prevented the glycogen repletion in both types of muscles. During the exercise as well as during the post-exercise recovery the hyperglycemic effect of adrenaline was decreased.

Effect of decreased availability of substrates on intramuscular triglyceride utilization during exercise.

Intramuscular triglycerides mobilization during prolonged physical exercise was examined in rats fed ad libitum, in rats fasted for 24 h and in rats treated with nicotinic acid. It has been found that during exercise the intramuscular triglyceride level was markedly reduced only in the red muscle but not in the white and intermediate muscles. Fasting significantly augmented the utilization of triglycerides in the red muscle during exericse. The post-exercise triglyceride level in the red muscle of the rats treated with nicotinic acid was similar to that in the control group whereas blood FFA level, in the nicotinic acid-treated group was much lower than in the control group. Nicotinic acid increased glycogen utilization in the liver and in the skeletal muscles during exercise. It may be concluded that the major cause of the reduction of the triglyceride level in the red muscle during exercise is a developing shortage of available carbohydrates. The greatly elevated blood FFA level during exercise does not seem to have a sparing effect on the intramuscular triglyceride level during exercise. However, it does spare glycogen content in the liver and the skeletal muscles.