Studies of human antagonistic muscles after rupture of the tendon of biceps brachii

The fibre type ratio and the cross sectional areas of fibres were studied in triceps brachial muscle after rupture of tendon of the biceps brachial muscle in man. On the healthy and injured sides of the m. triceps brachii, the mean value of type 1 fibres was 51.9% and 52.4%, respectively. The mean cross sectional area of fibre on the two sides of the triceps muscle varied considerably among individuals without any significant correlation to injury of the biceps tendon.     

Mucosubstances in the human skeletal muscles.

With histomchemical, and electronmicroscopic-histochemical methods two types of human skeletal muscle fibres were established. The first type of muscle fibres does not contain acidic mucosubstances. The staining reactions and cellulase digestion indicate that, the neutral polysaccharides are cellulose-like substances. The second type of fibres contains only acidic mucosubstances, hyaluronic acid and chondroitine sulphate. The author suggests that the mucosubstances have joint function. These polysaccharides contributed to the jointing both of myofibrils and sarcomers. The polysaccharides can be exhibited in the joint points of contractile elements. In mechanical injury this point became disintegrated.     

Proximal skeletal muscle alterations in streptozotocin-diabetic rats: a histochemical and morphometric analysis.

The response of rat quadriceps muscle fibers to chronic streptozotocin (STZ) diabetes was studied. Transverse sections of rectus femoris muscle from diabetic and weight-matched control rats were assayed for myofibrilar adenosine triphosphatase (ATPase) and nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR). A quantitative analysis was carried out by an automatic interactive analysis system focused on the fiber type size and distribution. STZ-induced diabetes caused important effects in this muscle, with changes in the distribution of oxidative enzyme reactions, type I fiber hypertrophy, and type II fiber atrophy, which was greater in type IIB than in type IIA. It is concluded that hypoinsulinism produces morphological alterations in proximal skeletal muscle fibers that are similar to those of neurogenic myopathy. Thus the pathological changes in these mammalian muscle fibers could explain the clinical syndrome seen in diabetic patients called "diabetic symmetrical proximal motor neuropathy," perhaps the least understood of the major neuropathic complications of diabetes.     

Ultrastructural alterations in cardiac and skeletal muscles in experimental diabetes mellitus

In 18 alloxan-diabetic and 12 metabolically healthy dogs cardiac and skeletal muscles have been studied electronmicroscopically. Myopathy-like alterations, as widening of Z band material, alterations of mitochondria as well as of collagen fibers were observed in the diabetic myocardium. In skeletal muscle nemalin bodies were found. These latter alterations don't develop in insulin-treated diabetic state.     

Aging of human skeletal muscles

Normal aging in humans is associated with progressive decrease in skeletal muscle mass and strength (sarcopenia) which contributes to frailty and falls. The age associated changes in body composition result from lower levels of anabolic hormones, oxidative damage, neuromuscular alterations and a general decrease in muscle protein turnover. In this review we discuss the potential mechanisms and physical activity as prevention and treatment of sarcopenia.     

The value of enzyme histochemical techniques in classifying fibre types of human skeletal muscle. 1. Adult skeletal muscles with no apparent disease of the neuromuscular system.

Fibre-type classification of human skeletal muscle into type I and type II fibres is mostly based on their slight or strong staining with the myosin adenosine triphosphatase reaction. In order to evaluate the reliability of this screening technique a combined histochemical and biochemical study was performed on normal and diseased skeletal muscle of human subjects. In the present investigation activities of enzymes which play a role in the aerobic and anaerobic pathways and which can characterize fibre type, were examined in muscle specimens, with no apparent disease of the neuromuscular system. Special attention is given to the maximal activities of phosphofructokinase and fructose-1,6-diphosphatase, the rate limiting enzymes for the regulation of the glycolysis and glyconeogenesis, respectively. A most important feature of the biochemical findings is the constancy of the activity ratios of the examined enzymes. From these results and from the histochemical results it can be concluded that in apparently normal adult human skeletal muscle the ATP-ase technique for type I and type II typing is reliable. For fibres with an intermediate intensity of staining with the myosin ATPase technique of typing it is also necessary to apply other enzyme histochemical techniques.     

Histochemical profiles of guinea-pig intrafusal fibres in normal muscles and after denervation, cordotomy and tenotomy

Synopsis Histochemical profiles of intrafusal fibres were analysed in normal muscles and in denervated, cordotomized and tenotomized preparations. Based on ATPase activity at polar regions, normal intrafusal fibres were classified as (I) ATPase-light fibres showing low or low-moderate activity when pre-incubated in either an acid or alkaline medium; (2) ATPase-dark fibres demonstrating high activity when preincubated in either an acid or alkaline medium and (3) ATPase-reversing fibres displaying low to moderate activity when pre-incubated in an acid medium, but showing high activity when pre-incubated in an alkaline medium. Four weeks after nerve section contrasting responses were seen between intrafusal fibre types. The ATPase-reversing fibres showed large decreases in polar cross-sectional area and NADH-diaphorase (NADH-D) activity, whereas fibres of the ATPase-light and ATPase-dark types were less subject to atrophy and their NADH-D levels were frequently increased. This differential effect suggests that ATPase-reversing fibres are trophically more dependent on neural innervation than ATPase-light and ATPase-dark fibres. After cordotomy and tenotomy no such marked differential responses were noted between fibre types.     

Capillaries of the intrinsic nerves of human skeletal muscles

Development of blood capillaries in the human intraorganic nerves has been studied. The intramuscular nerves of fetuses, newborns, children and mature persons (88 cases in all) make the object of the investigation. Combination of light optic methods and electron microscopy is used. The development of blood capillaries of the human intraorganic nerves is a complex process, indissolubly connected with development of myelin and amyelin conductors. The capillaries in the nerves appear on the 3d month of the intrauterine development and their structure is the most favourable for intensively proceeding, at this time, the myelinization process. With progress of nervous fibers and stromal elements, differentiation of the blood capillaries takes place. By the 6th month of the interuterine life, the capillaries of the intramuscular nerves are mainly formed. The structural unit in interrelation of the capillaries and nerve elements is the complex: capillary-lemmocyte-nervous fiber. Further changes are of slower character.     

Relationship between structure and T-lymphocyte maturation in human thymomas. Enzyme histochemical and immunohistological studies

Twenty-six human thymomas were studied in an attempt to correlate their morphological appearance with the type and degree of T-lymphocyte maturation, as determined by acid alpha-naphthyl-acetate esterase (ANAE) activity and immunological analysis. Four normal human thymuses were used for purposes of comparison. Two morphological patterns were identified in the thymomas. The distinction was based largely on similarities between the neoplastic epithelial cells and normal cortical and medullary epithelial cells, and on the relative proportions of epithelial cells and lymphocytes. By these criteria "medullary" and "cortical" patterns were identified. In several thymomas both patterns were present in the same tumor ("mixed-type pattern"), producing alternating dark cortical-like areas and lighter foci of medullary differentiation. A good correlation was found between the two patterns and the phenotype of the T-associated lymphoid component. ANAE activity, which was completely lacking in normal cortical thymocytes, was almost absent in the phenotypically immature T-cells of cortical-type thymomas. By contrast, in the medullary-type thymomas, T-cells showed immunological features in common with medullary thymocytes. This was characterized by strong ANAE activity in the majority of cells with a staining pattern corresponding to that of peripheral T-lymphocytes. In addition, most of the proliferating epithelial cells in medullary-type thymomas stained strongly with anti-cytokeratin and anti-epidermal-type keratin antisera. In the mixed-type thymomas the epithelial cell morphology and the immunohistochemical and enzymic features of the T-cells were found to be closely related to the respective cortical--or medullary-like areas. It was concluded that the various characteristics of normal thymic cortex and medulla studied are also present in thymomas. In particular, in medullar-type thymomas the presence of many of the features of normal thymic medulla, such as a squamous cell component, macrophages and interdigitating reticulum cells, may constitute a microenvironment which operates actively in T-cell education. This may account for the functional activities, characteristic of peripheral T-lymphocytes, which T-lymphocytes attain in these thymomas.     

Functional and clinical significance of the architecture of human skeletal muscles

The architectural properties of the triceps surae muscle were studied in vivo in groups of healthy subjects (eight men) and patients with locomotor function disorders (four men and four women) with the ankle joint positioned at a plantar flexion 0° and the knee set at 90° (neutral position). In this position, using ultrasonic scanning, longitudinal ultrasonic images of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (Sol) muscles were obtained when the subject was relaxed (the passive state) or performed isometric plantar flexion (50% of the maximum voluntary contraction (MVC), the active state). The fascicle lengths, fascicle angles, and muscle thickness were determined. In the passive state, the fascicle lengths of the MG, LG, and Sol muscles in the group of healthy subjects were 33, 35, and 30 mm and the pennation angle, 25°, 19°, and 25°; in the group of patients with motor disorders, 38, 39, and 29 mm and 21°, 19°, and 24°, respectively. The MG, LG, and Sol thicknesses in the group of healthy subjects were 15, 13, and 12 mm, and in the group of patients with motor disorders, 14, 12, and 14 mm, respectively. In the active state (50% of the MVC), the MG, LG, and Sol fiber lengths in the group of healthy subjects shortened by 31, 24, and 18%; the fiber pennation angle increased by 60, 41, and 41%, respectively. In the group of patients with motor disorders, the fiber lengths shortened by 28, 14, and 18% and the fiber pennation angle decreased by 28, 26, and 36%, respectively. The MG, LG, and Sol thicknesses in the group of healthy subjects increased by 9, 22, and 18%, while in the group of patients with motor disorders the thickness decreased by 4% in the MG and increased by 11 and 4% in the LG and Sol muscles, respectively. Different fiber lengths and pennation angles and their changes upon contraction might be related to differences in the force-producing capabilities of the muscles and the viscoelastic properties of muscle tendons and aponeuroses.     

The reliability of histochemical fibre typing of human necropsy muscles

Summary The reliability of muscle fibre typing of post mortem specimens was investigated with special reference to the influence of time and temperature. In specimens stored at +4° C, muscle fibre typing could be reliably performed up to at least ten and fifteen days post mortem for the masseter and biceps brachii muscles respectively. The corresponding figures for storage at room temperature were three and six days. The difference in the preservation of enzyme activity between masticatory and limb muscles might be related to the demonstrated difference in the fibre type composition and thus the enzyme content and energy sources.