摘要:

AbstractTo investigate annulate lamellae (AL) with nuclear changes, ultrastructural time course studies were done of the reversible end‐plate myopathy in the soleus muscles of rats exposed chronically to a high dose of the anticholinesterase drug neostigmine. At the earliest stage (2 hours) in which severe subjunctional damage involving a nuclear lesion (nuclear pyknosis) was prominent, AL profiles were undetectable. At the intermediate stage (7, 21 days), in which the subjunctional organelles tended to cluster and nuclear pyknosis often accompanied degenerative features, most AL laid near the surface of the abnormal nuclei, where there were signs of elimination or formation of pores, as well as a progression of changes leading to the loss of pores. At the late stage (56 days), in which muscle repair was nearly completed and euchromatic nuclei usually were found, there was a concomitant enhanced formation of false nuclear inclusions and of the AL profiles in these sites.Pores are packed on nuclear envelopes, which detach themselves from the nucleus and take the same profile as AL. This phenomenon can be envisioned not only in the euchromatic but also in the abnormal (pyknotic or degenerated) nuclei. Following nuclear reconstitution, the nuclear envelope folding is accelerated to induce the usual pattern of AL organization, i.e., budding from the invaginated nuclear envelop

ISSN:0003-276X    

DOI:10.1002/ar.1092250102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractVitamin A‐containing lipid droplets in the hepatocytes of rat liver were found to be exocytotically released from the cells in the form of a “lipid droplet—retinol‐binding protein (RBP)—immunoreactive complex” following intraportal injection of retinol (17, 33, 67, or 100 μg). Evidence that the lipid droplets contain vitamin A was obtained by fluorescence microscopy of vitamin A. Intraportal injection of retinol produced varied numbers and sizes of vacuoles in the hepatocytes. The substance within the vacuoles exhibited a meshwork‐like configuration in sections from slices incubated in a medium for revealing acid phosphatase activity or the corresponding control medium and was RBP‐immunoreactive and proteinaceous in nature. The occurrence and number of the vacuoles depended on the dosage of injected retinol, being greatest at a dosage of 100 μg of retinol and becoming progressively less at dosages of 67, 33, and 17 μg. The vacuoles were formed by vacuolization of cisternae of the rough endoplasmic reticulum. The formation of vacuoles reached a maximum 30 min after intraportal injection of 100 μg retinol, and the vacuoles and lipid droplets had almost disappeared from the hepatocytes after 90 min. Little or no esterase activity was found in lipid droplets in the hepatocytes before intraportal injection of retinol, but after the injection, lipid droplets that had fused with the vacuoles become strongly positive for this enzyme activity. This suggests that hydrolysis of retinyl esters may occur in the process of complex formation

ISSN:0003-276X    

DOI:10.1002/ar.1092250103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractRandom and serial thin sections of the nucleus in adult rat Sertoli cells were examined by electron microscopy. Besides the previously reported nucleoli and heterochromatin masses, the nuclei contain a coiled body and a new structure, the “mykaryon.”The coiled body is 835 nm in maximum diameter. It is composed of distinct elements referred to as “coils”. They are 32 nm wide on average and resemble the nucleolar pars fibrosa in their intense staining with heavy metal salts and their composition of narrow filaments. The coiled body is often close to a nucleolus, though no direct contact is established, and it sometimes exists at a distance from the nucleolus.The mykaryon is spherical, 460 nm in maximum diameter, and composed of a tridimensional network of 7–26 nm‐wide electron‐opaque “cords” separated by slighly thinner spaces. It has not been observed in the vicinity of a nucleolus. A literature survey showed no previous mention of a structure similar to the mykaryon. The coiled body and the mykaryon are interpreted as normal constituents of the Sertoli nucleus

ISSN:0003-276X    

DOI:10.1002/ar.1092250104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe cartilage extracellular matrix contains electron‐dense granules and fine filaments when studied electron microscopically after staining with ruthenium red. The matrix granules contain proteoglycans, while the filaments are thought to represent hyaluronic acid. In the present study partial extraction of proteoglycans from the cartilage prior to staining reduced the density of matrix components to allow visualization of a well‐developed network involving the matrix granules and hyaluronic acid filaments. The matrix granules frequently had multiple filamentous attachments and the network appeared to be formed by intersecting filaments with the matrix granules at points of intersection. A similar network was created in Sepharose CL‐2B beads when proteoglycans, link proteins, and hyaluronic acid were concentrated in the beads. Elimination of any one of these components resulted in failure to form a complete network. Purified proteoglycan monomers alone were sufficient to create matrix granules in the beads. Filaments were seen only when hyaluronic acid was added to the beads. The nature of the network suggests that some type of association between separate aggregates is occurring both within cartilage and within the Sepharose CL‐2

ISSN:0003-276X    

DOI:10.1002/ar.1092250105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe distribution of motoneurons innervating the primary depressor and elevator muscles of the wing of the domestic pigeon (Columba livia) was studied by using the retrograde axonal tracer lectin‐conjugated horseradish peroxidase (WGA‐HRP). Injection of WGA‐HRP into the pectoralis (pars thoracicus) labeled neurons in the ventromedial corner of the lateral motor column of the spinal cord. These neurons were arranged in a column extending from spinal segment X or XI to spinal segment XII or XIII. The pectoralis, the primary depressor muscle of the wing, consists of two parts which are anatomically and functionally distinct, the sternobrachialis (SB) and thoracobrachialis (TB). Injection into the SB labeled neurons in the rostral and middle regions of the pectoralis motoneuron column. In contrast, injection into the TB labeled neurons in the middle and caudal regions of the pectoralis motoneuron column. Injection into the primary elevator muscle of the wing, the supracoracoideus, labeled neurons in the lateral motor column in spinal segments X and XI. These motoneurons were located dorsolateral to motoneurons labeled following pectoralis injection. These data demonstrate musculotopic segregation of the motoneurons innervating the primary flight muscles in the pigeon and, further, illustrate that the SB and TB subregions of the pectoralis are innervated by discrete aggregations of motone

ISSN:0003-276X    

DOI:10.1002/ar.1092250106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractDespite the extensive literature concerning the neuropathy associated with diabetes, only limited information describes changes in the associated muscle. The objective of this study was to evaluate the histochemical and morphometric characteristics of diabetic muscle in the C57BL/KsJ db‐m strain of mouse. The histochemical analysis of myofiber type for the diabetic mouse revealed that the extensor digitorum longus muscle consisted of 53.1% type 2a, 46.0% type 2b, and 0.9% type 1 myofibers, a significant shift from the percentages found in the nondiabetic litter mates (44.4% type 2a, 55.6% type 2b, no type 1). Computer‐assisted morphometric analysis of myofiber size by fiber type indicated a significant difference in myofiber size for the type 2b fibers in muscles from diabetic mice. Similarly, there was a shift in the fiber size distribution to include a greater number of small type 2b myofibers when compared to controls. Skeletal muscle from diabetic mice exhibited a significant change in the percentage of fiber types, with an increase in the number of type 2a fibers, a fiber type grouping that implies possible denervation and reinnervation, and a decrease in myofiber size. These findings may explain why some diabetic patients complain of muscle weakn

ISSN:0003-276X    

DOI:10.1002/ar.1092250107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe formation of the fibrous sheath (FS) and outer dense fibers (ODF), two major cytoskeletal components of the tail of spermatozoa, was analyzed in the seminiferous epithelium by immunoperoxidase techniques applied to paraffin‐embedded testicular sections. Antibodies were prepared from purified FS and ODF fractions and from major 75 and 14.4 kDa FS polypeptides and major 32‐26 14.4 kDa ODF polypeptides. The immunostaining results showed that the production of FS and ODF proteins appeared to be exclusive to step 9‐19 spermatids and lasted over the duration of a full cycle of the seminiferous epithelium, or 12.8 days. During this period there was seemingly an initial lag of short duration between the synthesis and assembly of FS and ODF proteins followed by a long process of coordinated activity. Peak cytoplasmic immunoreactivity was reached in step 15 for FS proteins and midstep 16 for ODF proteins and and remained elevated thereafter for approximately 80 hr for both FS and ODF proteins. The immunoreactivity was more uniform and diffused for FS proteins and granulated or clumpy for ODF proteins. Assembly of FS proteins along the axoneme proceeded in a distal to proximal direction while for ODF proteins assembly proceeded in a proximal to distal direction. The main route of elimination of residual cytoplasmic FS and ODF proteins appeared to take place through the cytoplasmic droplets and residual bodies, respectively. There appeared to be no variation in step reactivity between the major ODF polypeptides tested and only minor variation in step reactivity between the major FS polypeptides tested. However, although the 14.4 kDa polypeptides of FS and ODF share antigenic determinants, they do not appear to be identical, because they presented different immunolocalizations during spermiogenesis and different directions of assembly along the ax

ISSN:0003-276X    

DOI:10.1002/ar.1092250108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractSeparation and recombination experiments, employing a variety of tissue configurations in organ culture, were performed to determine the extent to which the epithelium of the maxillary process influences the viability of the underlying mesenchyme during organogenesis. The results of these studies indicated that the viability of mesenchyme of the maxillary process of early stage embryos was severely impaired when separated from the overlying epithelium. The influence of epithelium on the viability of mesenchyme was stage dependent; that is, the requirement for the presence of epithelium for the maintenance of the viability of mesenchyme became progressively less pronounced at older developmental stages. The response of mesenchyme to the presence of recombined epithelium resulted in the appearance of a delimited zone of influence extending, within specific boundaries, from the epithelial‐mesenchymal interface. Preliminary data from homotypic (maxillary epithelium‐maxillary mesenchyme), heterotypic (limb apical ectodermal ridge—maxillary mesenchyme) and heterochronic (stage 28 epithelium‐stage 22 mesenchyme) recombination experiments indicated that viability of mesenchyme could be achieved only through direct epithelial‐mesenchymal contact which allowed restoration of normal morphological relationships at the interface of the tw

ISSN:0003-276X    

DOI:10.1002/ar.1092250109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractIn a recent study (Nitz et al., Exp Neurol 94:264–279, 1986) the validity of a rat animal model to examine effects of tourniquet compression and vascular occlusion on limb motor function, leg girth, and electrophysiologic changes was established. Here we report observations on sciatic nerve morphologic and morphometric alterations of these same animals. The hindlimbs of 90 rats were compressed by a pneumatic tourniquet at clinically relevant pressures (200 to 400 mm Hg) for 1 to 3 hours, and the sciatic nerve was assessed by light and electron microscopy at 1, 3, and 6 weeks post compression. The nerves were also examined from five additional animals at each of these time intervals following arterial ligation and sciatic nerve epineurectomy (30 rats). Percentage of degenerating myelinated nerve fibers and volume fraction of mast cells and fibroblasts were quantified morphometrically. The percentage of degenerating myelinated nerve fibers after moderate to severe tourniquet compression and vascular manipulation was similar and ranged from 15% to 45%. Tourniquet compression, but not vascular occlusion, resulted in an increase of mast cells and fibroblasts and disruption of endothelial cells of endoneurial vessels. The results suggest that clinically relevant tourniquet compression causes a secondary increase in vascular permeability, intraneural edema, and subsequent prolonged tissue ischemia, resulting in nerve degeneratio

ISSN:0003-276X    

DOI:10.1002/ar.1092250110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractFluorescence histochemical visualization of catecholamines and immunolabeling of dopamine beta hydroxylase (DBH) were employed to study noradrenergic nerve terminals and perivascular nerve specializations in the rat kidney. Plexuses of catecholamine‐containing and dopamine‐beta‐hydroxylase‐immunoreactive nerves innervate the intrarenal arterial tree and larger intrarenal veins. Some perivascular nerve bundles have specialized segments composed of clusters of axonal enlargements that are immunoreactive for DBH and fluoresce intensely in ultraviolet light after fixation in a solution of formaldehyde and glutaraldehyde or treatment with glyoxylic acid. No fluorescent neural structures were found in denervated rat kidney sections treated with glyoxylic acid. Many such structures are associated with arteriolar branches of interlobar, arcuate, and interlobular arteries and are composed, in part, of axonal enlargements that contain mitochondria, microtubules, and one or more clusters of synaptic vesicles. These perivascular nerve specializations may be sites of axoaxonal interactions between noradrenergic axons or between these axons and other types of autonomic or sensory axons. The synaptic vesicles evidently store large amounts of catecholamine, but there is no evidence whether it is released into the surrounding tissue. These structures may be involved in changes in intrarenal innervation patterns which may occur as the rat ages. Regardless of the autonomic or sensory nature of intrarenal neural structures, close association of most such structures with arterioles suggests some neurovascular inte

ISSN:0003-276X    

DOI:10.1002/ar.1092250111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY