摘要:

AbstractThe tridimensional structure of rough endoplasmic reticulum was examined with both high and low voltage electron microscopes in large ventral horn cells of rat spinal cord, by combining stereoscopic techniques with the use of thick sections selectively impregnated with heavy metal salts. In all neurons examined Nissl bodies appeared as well defined clusters of densely stained and profusely anastomosed plate‐, ribbon‐, and thread‐like cisternae. Plate‐like cisternae were variable in size, often showed a shallow curvature, and usually ran in short parallel arrays, separated from one another by fairly constant intervals. All gave rise at their edges to several ribbon‐like extensions which occasionally decreased in width distally, turning into thin, thread‐like cisternae. Characteristically, these ribbon‐like structures would emerge at an angle from their plate of origin and smoothly curve away from the plane of the plate to merge with ribbons or threads arising from adjacent or more distant plates. Most plate‐like cisternae were found at the periphery of Nissl bodies and tended to be oriented parallel to their surface. In contrast, the center of Nissl bodies was almost exclusively occupied by a complex network of ribbon‐and thread‐like cisternae. It is suggested that the basic plate/ribbon association here described in spinal motoneurons might be a constant feature of Nissl body architecture in various neuronal types, while the size, orientation, and relative proportion of plate‐like cisternae may vary according to the metabolic state and/or functional specia

ISSN:0003-276X    

DOI:10.1002/ar.1092070402

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

年代:1983

数据来源: WILEY

摘要:

AbstractSulfated glycosaminoglycans are an integral component of elastic cartilage. We have investigated the ultrastructural distribution of sulfated complex carbohydrates (CC)in the mature cartilage and the perichondrium of young rabbit auricles using the high iron diamine‐thiocarbohydrazide‐silver proteinate (HID‐TCH‐SP) and the tannic acid‐ferric chloride (TA‐Fe) methods. In the mature cartilage, HID‐TCH‐SP stained intracellular Golgi saccules of the mature face, secretory granules, and the extracellular matrix granules, but staining was not discernible in collagen fibrils and osmiophilic elastic fibers consisting of only amorphous elastin. The HID and TA‐Fe staining were similarly observed in matrix granules, whereas the elastic fibers and collagen fibrils lacked the staining. The pericellular matrix granules had a diameter of 34 ± 5 nm (mean ± SD; n = 30). Thiéry's periodate‐TCH‐SP (PA‐TCH‐SP) method stained vicinal glycol‐containing CC in collagen fibrils but failed to stain matrix granules and elastic fibers. In the perichondrium, HID‐TCH‐SP staining of the organelles was less intense in the flattened chondrocytes when compared with those in large mature chondrocytes. The extracellular HID and HID‐TCH‐SP staining were observed in the matrix granules. The diameter of pericellular matrix granules (19 ± 4 nm, mean ± SD; n = 30) was significantly smaller when compared to those in the mature cartilage (P<0.001). The HID‐TCH‐SP staining was closely associated with collagen fibrils. However, the staining was not seen in collagen fibrils and osmiophilic elastic fibers consisting of elastin and microfibrils. The PA‐TCH‐SP method stained collagen fibrils and microfibrils but did not stain the amorphous elastin. Thus these studies demonstrate that sulfated CC are packaged in chondrocyte secretory granules and are released into the extracellular matrix to form matrix granules, but are not incor

ISSN:0003-276X    

DOI:10.1002/ar.1092070403

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

年代:1983

数据来源: WILEY

摘要:

AbstractTo study the permeability of human amniotic epithelium to small molecular weight substances, pieces of nonplacental amnion, with attached chorion laeve and decidua, were exposed to solutions containing lanthanum salts and processed for electron microscopy. Lanthanum penetrated the intercellular spaces and often reached the basal lamina region. In addition, some lanthanum was bound to the glycocalyx of the microvilli on the apical surfaces of the cells. Little lanthanum was found deep to the basal lamina. The results suggest the intercellular pathway is of major importance in the movement of small molecules across amniotic epithelium.

ISSN:0003-276X    

DOI:10.1002/ar.1092070404

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

年代:1983

数据来源: WILEY

摘要:

AbstractSciatic nerves from young mice were incubated for 2–8 hours in 0.5% Triton X‐100 in 0.5 M ammonium acetate, a solution which solubilizes the large and small basic proteins of the myelin sheath. As previously noted (Peterson and Gruener, 1978), myelin sheaths from treated nerves extensively split and unravelled along major dense lines. Small focal areas of compact myelin remained. In freeze‐fracture replicas, areas of myelin with lamellar splitting contained few intramembranous particles, while membrane areas with greater than normal densities of particles were associated with the patches of compact myelin membrane. Fixation for as short a time as 15 minutes stabilized the myelin membrane enough to prevent the Triton X‐100 effects, even when incubations were extended to 20 hours. Controls, both untreated and 0.5 M ammonium acetate‐treated nerves, had predominantly compact myelin sheaths; their leaflets were covered with numerous intramembranous particles. The data suggest that Triton X‐100 alters the compact structure of peripheral nervous system myelin. In areas where lamellae are split and separated, there is a loss of intramembranous particles. It appears that the loss of intramembranous particles is related to the removal of the basic proteins which are located in major dense line regions of compact mye

ISSN:0003-276X    

DOI:10.1002/ar.1092070405

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe force generated within skeletal muscle fibers of vertebrates is transmitted to the tendon at the muscle‐tendon junction. Ultrastructural analysis of the murine muscle‐tendon junction following a variety of experimental manipulations has produced evidence that the muscle‐tendon junction can be described in terms of four principal domains (Trotter and Eberhard, 1983), two of which are discussed in the present report. Each domain is defined by the shape and orientation of its principal components, and by its position with respect to the plasma membrane. Theinternal laminais composed of actin filaments, with a center to center spacing of approximately 12 nm, oriented mainly parallel to the principal vector of contractile force, and to the plasma membrane. These filaments are cross‐linked into a structural unit, perhaps by the electron‐dense structures which are associated with them. The internal lamina is morphologically connected to the external lamina (lamina densa) by a population of fine filaments oriented approximately perpendicular to the principal vector of contractile force. These filaments which constitute theconnecting domain, are approximately 2–8 nm in diameter and are at least 50 nm long. They pass through three separate regions: the sarcoplasm between the internal lamina and the plasma membrane; the plasma membrane proper; and the extracellular space between the plasma membrane and the lamina densa. This third region is often referred to as the lamina lucida. These filaments are composed of at least three separate components in series, linked together by noncovalent interactions. The existence of these discrete structural domains implies that each has a different molecular composition and different mechanical

ISSN:0003-276X    

DOI:10.1002/ar.1092070406

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

年代:1983

数据来源: WILEY

摘要:

AbstractMononucleated cells located between the external lamina and sarcolemma of denervated muscle fibers within the extensor digitorum longus (EDL) and soleus muscles of adult mice were quantified and examined ultrastructurally from 3 to 65 days after ligating and removing a section of the sciatic nerve. During the first 2 weeks postdenervation, mononucleated cells in denervated muscles were morphologically indistinguishable from satellite cells observed in control muscles. With time, however, many of these satellite‐like cells appeared more active as evidenced by a decrease in their nucleocytoplasmic ratio and an increase in their mean percentage of euchromatin material. The number of satellite cells (expressed as a ratio of satellite cell nuclei to satellite cell nuclei plus myonuclei) did not increase significantly until 30 days postdenervation, at which time the mean percentage for the soleus muscle had risen from a control value of 4.1–8.5%, and for the EDL from 1.2–4.1%. Smalldiameter, presumably regenerating, myofibers were occasionally observed but only after 30 days denervation. The ultrastructural evidence plus comparisons of euchromatin distributions between myonuclei and satellite cell nuclei support the concept that an increase in the number of satellite‐like cells during denervation is more likely due to satellite cell proliferation than to the formation of mononucleated fragments utilizing preexisting my

ISSN:0003-276X    

DOI:10.1002/ar.1092070407

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

年代:1983

数据来源: WILEY

摘要:

AbstractCarbonic anhydrase (CA) isozyme I and isozyme II have been localized with the immunoperoxidase bridge method in cells of mouse and rat salivary glands and exorbital lacrimal glands. Immunostaining proved optimal in Carnoy fixed specimens for some sites and in Bouin fixed glands for other sites. Staining in mouse largely resembled that in rat glands, but minor species differences were observed. Serous acinar cells in the submandibular gland stained uniformly and exclusively for CA I. From 50 to 100% of the serous acinar cells in the parotid glands evidenced content of both CA I and CA II. A minor population of serous acinar cells in the mouse exorbital lacrimal gland stained for CA I and CA II, but these glands in the rat failed to stain.Immunostaining was observed in ducts in Bouin fixed glands. Some cells in striated ducts of submandibular and sublingual glands stained for CA I and CA II and other cells in these ducts were negative. Such cellular heterogeneity was also observed in excretory ducts of submandibular and sublingual glands. These findings thus demonstrate the presence of CA in two morphologically and functionally diverse cell populations in rodent salivary glands.Immunolocalization of the CA isozymes in serous acinar cells and intercalated duct cells, presumably packaged in secretory granules, implies a role for this enzyme in salivary secretions whereas localization of CA in striated and excretory ducts suggests their traditional function in fluid and electrolyte transport.

ISSN:0003-276X    

DOI:10.1002/ar.1092070408

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

年代:1983

数据来源: WILEY

摘要:

AbstractIn this study we investigated the effects of chronic β adrenoreceptor blockade with atenolol on cellular and subcellular hypertrophy in spontaneously hypertensive rats (SHR). Atenolol was injected subcutaneously (20 mg/kg) twice daily commencing in four‐week‐old rats. The treated animals (SHR‐A) were compared to their nontreated controls and normotensive, Wistar‐Kyoto (WKY) controls at the age of 16 weeks. A group of atenolol‐treated WKY was also studied. Chronic drug treatment was effective in attenuating the rise in systolic blood pressure characteristic of SHR, but did not normalize the values to those of WKY. Cardiac hypertrophy, characteristic of SHR, was modified by drug treatment as evidenced by left ventricular weights as well as myocardial cell size. The cells from the subendocardium underwent selective hypertrophy in SHR which was attentuated by about 50% after atenolol treatment. Stereological analysis of electron micrographs showed that while relative mitochondrial volume was not affected by treatment, relative myofibrillar volume (%) decreased in both subepicardium (SHR = 63.28 ± 1.25; SHR‐A = 56.72 ± 1.37) and subendocardium (SHR = 66.53 ± 1.27; SHR‐A = 58.30 ± 1.51). This change raised the mitochondrial/myofibrillar volume ratio, which is characteristically low in SHR compared to WKY. Sarcoplasm, which included all cell constituents except mitochondria, increased with atenolol treatment, but water concentration remained unchanged. The data suggest that attenuation of hypertrophy in SHR after β blockade is associated with selective effects on the myocardial cell involving primarily the myofibrill

ISSN:0003-276X    

DOI:10.1002/ar.1092070409

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

年代:1983

数据来源: WILEY

摘要:

AbstractInjections of horseradish peroxidase (HRP) into the right or left ovary of the rat produced labeling of perikarya in both nodose ganglia and ipsilateral dorsal root ganglia (DRGs) from T10to L2. The greatest concentration of labeled cells was in T13and L1, DRGs. It is suggested that visceral afferent fibers from the ovary may mediate visceral reflexes that modulate ovarian function.

ISSN:0003-276X    

DOI:10.1002/ar.1092070410

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe distribution of adenylate cyclase in testis, by means of a specific substrate adenylyl‐imidodiphosphate (AMP‐PNP), has been determined. Membrane‐associated reaction products, indicative of adenylate cyclase activity, are localized by a complete cytochemical medium (containing 10 mM NaF) at the level of the basal compartment of the seminiferous epithelium, on the basal surface of Sertoli cells, and on adjacent plasma membranes of Sertoli cells and spermatogonial cells. At the level of the adluminal compartment, reaction products were found on adjacent plasma membranes of Sertoli cells and early or elongated spermatids. Adenylate cyclase reaction products are detectable by a basal incubation medium (without 10 mM NaF) only in the adluminal compartment on the spermatid plasma memb

ISSN:0003-276X    

DOI:10.1002/ar.1092070411

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

年代:1983

数据来源: WILEY