摘要:

The sarcomere length-joint angle relationship was measured in 7 different muscle-joint complexes (n = 43 muscles) of the frog hindlimb (Rana pipiens). Muscles studied included the cruralis, iliacus internus, gastrocnemius, gluteus magnus, gracilis major, semimembranosusand the semitendinosus. Muscle-joint complexes were mounted in a jig and submerged in chilled Ringer’s solution. Joints were rotated throughout their range of motion, while sarcomere length was measured by laser diffraction. Muscles were then formalin fixed and architectural properties determined by microdissection of individual muscle fibers. Sarcomere length change per degree of joint rotation (dLs/dθ) ranged from a low of 3.7 nm/degree for the cruralis muscle acting at the knee to a high of 12.5 nm/ degree for the semitendinosus muscle acting at the hip. Values for dLs/dθ were significantly different between all muscles (p < 0.001), and dLs/dθ values for muscles acting at the hip were significantly greater than those for muscles acting at the knee (p < 0.005). dLs/dθ was negatively correlated with fiber length, suggesting a balance between fiber length and moment arm in most muscle-joint systems. However, many exceptions to this generalization were noted. These data suggest that different muscle-joint systems are ‘designed’ for differential contribution of muscle force production to the joint torque profile. The low variability of these data also suggests that sarcomere number is tightly regulated in these muscle-joint systems but not simply as a result of the total in vivo muscle excu

ISSN:1422-6405    

DOI:10.1159/000147380

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The existence of lectin-binding sites was investigated in the cecum of Balb-c mice at seven developmental stages ranging from 18 days post conception (p.c.) to 8 weeks after birth. Nine horseradish-peroxidase-conjugated lectins (concanavalin A, Triticum vulgaris, Dolichus biflorus, Helix pomatia, Arachis hypogaea, Glycine maximus, Lotus tetragonolobus, Ulex europaeus, Limulus polyphemus) were applied to 5- to 7-µm thin paraffin sections of Bouin-fixed tissue. After DAB staining the sections were evaluated by light microscopy. It was shown that each lectin exhibits a unique developmental pattern. The adult binding patterns were established at the age of 3-4 weeks with only minor changes occurring thereafter. Considerable differences in binding patterns occurred not only between lectins of different groups but also between lectins with the same nominal monosaccharide specificity

ISSN:1422-6405    

DOI:10.1159/000147381

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The influence of continuous electromagnetic fields (0,181 or 361 Gs/cm2) on tht development of chick embryo (n = 144) was studied. Several parameters were determined at days 5,10 and 15 of incubation: stage (following Hamburger and Hamilton), vertex-coccyx length (size) and weight. At 5 days of incubation, all embryos showed a similar stage. However, at days 10 and 15, the embryos exposed to 181 Gs/cm2 showed a stage significantly superior to that of the others. There were no differences between the exposed embryos and the control ones with regard to weight and stature, except at 15 days when the embryos exposed to 361 Gs/cm2 showed greater weight and stature than those of the controls.

ISSN:1422-6405    

DOI:10.1159/000147382

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

These examinations were based on the discussion whether in demyelinating diseases anti-lipid antibody associated with brain macrophages could have a cytotoxic effect on oligodendrocytes. We used mixed brain cell cultures of newborn rats where, among others, both oligodendrocytes and vacuolated macrophage-like cells were found. On these macrophage-like cells, the presence of Fc-receptors was proven. Besides Fc-receptor-dependent phagocytosis, these cells showed an Fc-receptor-independent type of phagocytosis. The Fc-receptor-bearing cells moved within the culture and adhered to glass fibers. In the cytoplasm of these cells, unspecific esterase, acid phosphatase and peroxidase could be visualized. The vacuolated cells showed strong autofluorescence, expressed a surface marker found on all types of rat leukocytes and were marked by Griffonia simplicifolia lectin. These results definitely characterized the vacuolised cells as macrophages. We saw globular and pleomorphic macrophages. After incubation of anti-GC serum in a highly diluted solution, significantly more macrophages bound to oligodendrocytes than in the controls. In these cases, we found target cell lysis. It could be shown in vitro that anti-GC serum together with macrophages of neonatal brains can induce a cy to toxic effect on oligodendrocytes.

ISSN:1422-6405    

DOI:10.1159/000147383

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The purpose of this study was to examine the effects of a known inhibitor, transforming growth factor-β1 (TGF-β1) versus the known stimulators insulin-like growth factor-1 (IGF-1) and dexamethasone (DEX) on pig preadipocyte differentiation in serum and serum-free primary cultures. In cultures with serum, preadipocyte and nonpreadipocyte replication was increased (p < 0.02) by IGF-1 and by TGF-β1 (p < 0.05; p < 0.001). IGF-1 (10 nM) enhanced preadipocyte differentiation (p < 0.05) in serum-supplemented (1% pig serum) cultures, whereas TGF-β1 (15 pM) reduced preadipocyte differentiation (p < 0.01) in the presence and absence of IGF-1. Furthermore, GPDH (SN-glycerol-3-phos-phate dehydrogenase) specific activity (marker that indicates differentiation) was decreased (p < 0.05) by adding TGF-β1to serum-free cultures, but TGF-β1 had little effect in serum-supplemented cultures. DEX significantly enhanced GPDH activity and fat cell cluster number, whereas pretreatment with TGF-β1· eliminated the DEX enhancement. We have shown for the first time that TGF-β1 can decrease (p < 0.01) the cellular secretion of IGF-1 by pig adipose tissue cells and counter the effects of exogenous IGF-1. These studies indicate that TGF-β1 may not inhibit adipocyte development in the initial growth phase, but may inhibit differentiation and/or hypertrophy (lipid filling) at a later stage of de

ISSN:1422-6405    

DOI:10.1159/000147384

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The object of this study was to investigate the applicability of the acrylic resin ‘LR White’ to immunolabelling of various antigenic determinants in aldehyde-fixed rat CNS tissue. Antibodies were used, which worked well in paraffin sections and therefore were suitable to detect antigens resistant to complete dehydration and heat. Different LR White embedding protocols were employed in order to select the preparation conditions that adequately preserved both the antigenicity and fine structure. Specimens were completely dehydrated with up to 100% ethanol, which was followed by various infiltration times with LR White monomer. Polymerization of the resin was induced by heat, a chemical catalytic procedure (accelerator), or ultraviolet (UV) light. Paraffin, as well as semithin and ultrathin LR White sections were incubated with antibodies reacting to antigens located on the cell surface (stage-specific embryonic antigen-1; SSEA-1), within the plasma membrane (myelin basic protein), in the cytosol (HNK-1, S100 protein), in the cytoskeleton (GFAP, vimentin, neurofilament protein, INT-FIL), and in the extracellular matrix (laminin). All of the examined antigens were immunocytochemically detectable in paraffin-embedded material, while the carbohydrate moieties, HNK-1 and SSEA-1, were not immunoreactive in LR White sections. However, in cryostat sections processed for pre-embedding immunoelectron microscopy, the HNK-1 epitope and SSEA-1 were immunolabelled. Polymerization carried out under UV light led to better structural preservation of brain tissue than resin cured with heat or catalyst. The length of prior infiltration with monomer apparently had no effect on tissue preservation. Consequently, UV light-induced polymerization of LR White gives acceptable morphology of brain tissue. However, the use of this acrylic resin is restricted to the detection of some CNS antigens o

ISSN:1422-6405    

DOI:10.1159/000147385

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The alimentary tract of typical anurans shortens extensively at metamorphosis when the microphagous tadpole transforms into a macrophagous frog. We used methylene blue vital stain and Sihler stain, in conjunction with microdissection to map the distribution of the gastric branch of the vagus nerve in green frogs (Rana clamitans) before and after metamorphosis. After metamorphosis, termnal divisions of the gastric branch can be observed on the tunica musculosa extending as far as the pylorus. In the tadpole, the gastric branch ends abruptly on the esophagus. The premetamorphic pattern of innervation is consistent with the absence of digestive activity in the foregut before metamorphosis. Preliminary experiments, involving stimulation of the gastric branch of the vagus in the tadpoles, confirm the anatomical observation of the absence of vagal innervation before metamorphosis.

ISSN:1422-6405    

DOI:10.1159/000147386

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The blood supply of brachial plexus is described by means of lightened injected specimens of older human fetus. The following arteries have direct branches to brachial plexus: the aortic arch/brachiocephalica trunk, subclavia a., thyrocervical trunk, ascending cervical a., transverse cervical a., suprascapular a., and the acromial network. Secondary branches leave them that partly anastomose and also return from distal to proximal. The blood supply is luxurious.

ISSN:1422-6405    

DOI:10.1159/000147387

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

Effects of 5-gravity environment on the ultrastructure of the parathyroid glands of norepinephrine-treated golden hamsters were studied. In the centrifuged animals treated with norepinephrine, the volume density occupied by the Golgi complexes associated with numerous prosecretory granules was significantly increased compared with that of the control, centrifuged and norepinephrine-treated animals, as well as the volume density occupied by the cisternae of the granular endoplasmic reticulum compared with that of the control and centrifuged animals. In addition, in the centrifuged animals treated with norepinephrine, numerous secretory granules were situated close to the plasma membrane. It is suggested that the synthesis and release of secretory granules may be markedly stimulated in the parathyroid glands of the norepinephrine-treated golden hamsters subjected to a hypergravity environment.

ISSN:1422-6405    

DOI:10.1159/000147388

出版商:S. Karger AG    

年代:1992

数据来源: Karger

摘要:

The ligamentum coracohumerale, as the anterior limit of the bursa subacrot sialis, runs into the shoulder joint capsule, connecting – broadly based – above the sulcus intertubercularis. It does not, however, originate – as described previously – from the base of the processus coracoideus (viewed frontally), but rather medially from the base, i.e. on the side of the fossa supraspinatus. The sliding mechanism starting at 50° affects the parietal sheet of the bursa subacromialis, whereby the laterally situated section slides under the medially situ; îed section. With an abduction of up to 50°, the lateral section congests in froti of the corner of the acromion, sliding from there under the acromion, so that the – hitherto – medial section is located above the section now sliding away beneath it. This sliding mechanism continues on up to 100°. At this point the parietal sheet of the bursa subacromialis lies as follows: The section that had been situated laterally at the beginning of the sliding mechanism now lies caudally to the section that had lain medially at the outset. The bursa subacromialis does not slide fully into the fossa supraspinatus, as in all of the cases observed, it is firmly connected, together with the fascia subdeltoidea, to the corner of the acrom > n. The visceral sheet does not change in the course of the sliding mechanism as described, as it is connected to the fascia of the supraspinatus muscle – with the exception of a medial stretch of 16 mm. A further finding deals with the course of the muscles of the caput breve of the biceps brachii. Individual muscle fibre components do not connect to the processus coracoideus, but rather run before the tip of the processus coracoideus into the ligamentum coracoacromiale, radiating not only into the ligamentum coracoacromiale, but also – certain components – into the shoulder joint capsule. Through this, the ‘aponeurosis tendinis brachii’ forms a tendon roof in front of the processus coracoideus that extends to the structures running along the head of the humerus. The muscle fibre components of the caput breve of the m. biceps brachii radiating into he shoulder joint capsule, together with the muscles of the rotator cuff and the ligamentum coracohumerale, keep the shoulder joint capsule tense, thus prevent

ISSN:1422-6405    

DOI:10.1159/000147389

出版商:S. Karger AG    

年代:1992

数据来源: Karger