摘要:

AbstractTo study intramembrane events leading to the establishment of intercellular junctions between epithelial cells in vitro, we examined monolayer cultures of a rat liver cell line by an in situ freeze‐fracturing technique (Pauli et al., J. Cell Biol.,72:763, 1977). Our observations indicate that an early step of junction formation between liver cells consists of the differentiation of a particle‐poor membrane stretch showing a honeycomb pattern of shallow P‐face depressions or E‐face bulges (“formation band”). This change in membrane organization precedes and accompanies the subsequent aggregation of junctional particles. The latter process results in the formation of irregular particle islands with peripheral branchings which tend to encompass the depressions in the membrane. The linear branchings grow and interconnect in a network of beaded strands, which gradually transform into smooth tight junctional fibrils, as previously described in fetal liver in vivo (Montesano et al., J. Cell Biol.,67:310, 1975), while the particle islands assume the typical configuration of mature gap junctions. Formation bands are particularly prominent between liver cells grown in the presence of hydrocortisone (5 μg/ml) in the cu

ISSN:0003-276X    

DOI:10.1002/ar.1091980302

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe effects of noradrenaline (NA), L‐3, 4‐dihydroxyphenylalanine (L‐DOPA), 5‐hydroxydopamine (5‐OHDA), 6‐hydroxydopamine (6‐OHDA), and reserpine (RES) on the uptake, accumulation, and release of amines in cate‐cholamine‐containing specific endothelial granules (SEG) of carp cerebral veins and their mode of formation were examined by fluorescence histochemistry and electron microscopy. The intramuscular injection of NA (4 mg/kg) or L‐DOPA (200 mg/kg) resulted in an increase in both the fluorescence and electron density of SEG. After the administration of false neurotransmitters, 5‐OHDA (190 mg/kg) or 6‐OHDA (200 mg/kg), the venous endothelia fluorescence almost completely disappeared but the SEG electron density increased. Following the injection of RES (15 mg/kg), the fluorescence intensity and SEG electron density showed no sign of decrease, as was expected, but in fact increased. It is suggested that the SEG are able to take up and accumulate exogeneous amines and that these mechanisms are RES‐resistant. The electron density of SEG increased in proportion to the amount of amines in the SEG. The swelling and fragmentation of rough endoplasmic reticulum cisternae and the accumulation of dense material within the cisternae suggests the possible participation of these or

ISSN:0003-276X    

DOI:10.1002/ar.1091980303

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

年代:1980

数据来源: WILEY

摘要:

AbstractAn attempt has been made to characterize the nature of the unidentified cell processes participating in gap junctions in the odontoblast layer. In peripheral and pulpal nerves, there is a strong relationship between axon caliber and microfilament and microtubule populations. This characteristic, together with the ratio of microtubules to microfilaments, has been measured and compared for four types of cell processes found in the dental pulp, including those participating in gap junctions. The processes taking part in the gap junctions cannot be distinguished from pulpal axons on the basis of microtubule‐to‐microfilament ratio nor on the relationship between microtubule and microfilament population and process caliber. While these findings do not prove that the “gap members” are nerve fibers, it does support the hypothesis that the processes taking part in gap junctions in the peripheral dental pulp are nerve

ISSN:0003-276X    

DOI:10.1002/ar.1091980304

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe distribution and extent of the lymphatic circulation in the renal cortex was analyzed in three dogs under conditions of unimpeded lymph and urine flow. The kidneys were drip fixed with acrolein in vivo, and cortical tissue strips were prepared for light and electron microscopic examination. Analysis of 90 tissue strips revealed 38 cortical lymphatics, one third of which were intralobular in position. The intralobular lymphatic capillaries were related primarily to tubules, afferent arterioles, or renal corpuscles. The remainder of the lymphatics were located in interlobular connective tissue areas in association with the interlobular blood vessels. Interlobular lymphatics had a surface area twice that of intralobular vessels. Stereological analysis was used to estimate the volume density of the components of the renal cortex. The volume density of lymphatics was found to be 0.0014, but because of the relative infrequency of lymphatics, this value was considered to be approximate. The volume density data for non‐lymphatic renal components were found to be in close agreement with published data. From these volume density values it was concluded that the volume of cortical lymph in a functioning dog kidney is equivalent to about 1% of the volume of blood in the cortical peritubular capillarie

ISSN:0003-276X    

DOI:10.1002/ar.1091980305

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe autonomic innervation of smooth muscle in fresh biopsy specimens of the human urinary bladder, bladder neck and urethra has been examined using specific neurohistochemical techniques. Acetylcholinesterase‐containing nerve fibers have been demonstrated amongst the smooth muscle cells in all the biopsy samples. Enzyme‐positive fibers formed a plexus, the density of which varied dependent upon the region from which the biopsy material was obtained. Catecholamine (noradrenaline)‐containing autonomic nerve fibers were observed amongst smooth muscle cells of the vesico‐urethra junction; other than for perivascular nerve plexuses. Noradrenergic fibers were absent from biopsy samples of other regions. Juxtamural, acetylcholinesterase‐positive neurones were present in some samples, and a proportion of these cell bodies were closely related to noradrenergic nerve terminal regions. These findings are discussed in relation to those of other workers who have examined the innervation of the mammalian lower urin

ISSN:0003-276X    

DOI:10.1002/ar.1091980306

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe presence of structures bridging the inner and outer acrosomal membranes of the equatorial segment of boar spermatozoa was clearly demonstrated in cells that have undergone a variety of treatment procedures to displace the electron‐dense contents of the acrosome.En‐facesections show bridges to be punctate and not linearly extensive as might be suggested by sections perpendicular to the flat plane of the head. About 4.5 × 105bridges, each measuring 7 nm across and spaced 7 nm apart, are arrayed hexagonally in the equatorial segment, but bridges are not present within the principal segment of the acrosome. Short‐term treatment with trypsin partially digests the bridges, but does not disrupt the spacing or strict parallel configuration of equatorial segment membranes. However, short‐term treatment with pronase digests most bridges and effectively disrupts the typical configuration of the equatorial segment. Freeze‐fracture of the cytoplasmic face of the acrosomal membranes of the equatorial segment reveals a pattern throughout the phospholipid layer of the membrane which is similar to the pattern of bridges present inen‐facethin sections of the equatorial segments. The data suggest that numerous bridges link the inner and outer acrosomal membranes of the equatorial segment of the acrosome and they play a major, if not an exclusive, role in maintaining the close spacing and parallel arrangement of the membranes in this portion of

ISSN:0003-276X    

DOI:10.1002/ar.1091980307

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

年代:1980

数据来源: WILEY

摘要:

AbstractLight and electron microscopic studies of the spermatic granuloma of the rat vas deferens which arises post‐vasectomy were undertaken to determine if such granulomata exhibit the morphological features typical of granulomata described in other systems. Vasectomy was performed utilizing a technique of division and fulguration, and tissues for study were fixed in situ by means of vascular perfusion at 2, 4, or 12 weeks post‐operatively. Invariably, a spermatic granuloma formed at the testicular end of the sectioned vas by 2 weeks post‐vasectomy. At the time periods studied, the granulomata exhibited a cellular wall of variable thickness and complexity surrounding a central mass of sperm. This wall consistently was divisible into (1) a loosely arranged interface region populated by neutrophils and other spermiophagic cells, and (2) a more peripheral, compactly arranged region populated primarily by macrophages and epithelioid cells. Multinucleate giant cells were especially prominent in the later stages studied. Peripheral to the wall, but without an intervening basal lamina, lay a loosely organized, highly vascular connective tissue region containing only sparse collagen and few fibrocytes. Here, too, macrophages, epithelioid cells, lymphocytes, and plasma cells were noted in abundance. A well‐developed capsule composed of fibrocytes, collagenous bundles, and smooth muscle cells surrounded the granuloma. Such features conform to those descriptions in the literature of chronic granulomatous infla

ISSN:0003-276X    

DOI:10.1002/ar.1091980308

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

年代:1980

数据来源: WILEY

摘要:

AbstractThe nature of the intensely fluorescent cells (IFC) in the livers of male Sprague‐Dawley rats was evaluated using histochemical and pharmacological techniques. The number and distribution of IFC in portal areas were quantified using some of these techniques. Cells which were metachromatic as well as fluorescent for serotonin, histamine, and heparin were observed in the connective tissue of the portal space, hilus, and capsule of the liver. Cells with the characteristics of chromaffin, enterochromaffin, or enterochromaffin‐like cells were not seen in these locations. Intravenous administration of compound 48/80, a known mast cell degranulator, caused a significant decrease in the number of fluorescent and metachromatic cells in the portal areas of the liver. However, no significant difference was found in the number of cells counted in either the 48/80 or control groups when comparing the data from several histochemical methods. These results provided evidence that: (1) IFC demonstrate both fluorescence and metachromasia and, therefore, are mast cells, (2) compound 48/80 causes a comparable decrease in the number of serotonin and histamine fluorescent as well as metachromatic cells, indicating concomitant rather than differential release of serotonin, histamine, heparin, and/or other metachromatic substances, and (3) each of the three histochemical methods appears of equivalent sensitivity when used to study the effect of various factors (i.e., 48/80) on the release of endogenous substances from IFC. The results of this study indicate that the effects of 48/80 in vivo might be mediated through the release of various vasoactive substances from these IFC (mast cel

ISSN:0003-276X    

DOI:10.1002/ar.1091980309

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

年代:1980

数据来源: WILEY

摘要:

AbstractLamellar bodies of type II alveolar epithelial cells are the intracellular storage sites of lung surfactant, while tubular myelin figures are an extracellular surfactant form found in the alveolar fluid. A refined procedure was used to isolate intact lamellar bodies from rat lung homogenates in a fraction of high purity and yield. The stability of isolated lamellar bodies under various conditions was determined by electron microscopy. Lamellar bodies were completely disrupted after incubation at 37, 24, and O°C for 0.6, 2, and 12 hr, respectively, in 0.33 M sucrose, 0.01 M HEPES (pH 7.4). In addition, they were completely disrupted after incubation for 1 hr in 0.33 M sucrose, 1 mM EGTA at 0°C or 0.154 M NaCl or 0.10 M sodium phosphate (pH 7.4) at 24°C. Incubation of isolated lamellar body fractions in medium containing 5 mM Ca++or Mg++at 37°C for 1 hr resulted in the appearance of tubular myelin figures. A procedure is also presented for the isolation of tubular myelin figures from rat lung lavage fl

ISSN:0003-276X    

DOI:10.1002/ar.1091980310

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

年代:1980

数据来源: WILEY

摘要:

AbstractIn order to identify the initial site of antibody formation in rat spleen, an investigation was made to determine the effects of different antigen dosages on the localization of specific antibodies against sheep erythrocytes (SRBCs). Sixty rats were intravenously injected with 1 ml of either 1%, 5%, or 10% suspensions of SRBCs and killed at days 1, 2, 3, and 4 after immunization. A tissue agglutination procedure in which the binding of SRBCs to cryostat sections of spleen was used to localized anti‐SRBC antibodies. Sections used for determination of SRBC binding patterns, and adjacent sections were stained for histological localization or processed for the determination of acid phosphatase (ACP) activity.Spleens of non‐immunized rats showing binding of SRBCs closely associated with the ACP‐positive marginal metalophils and marginal zone macrophages. This binding was not inhibited by preincubating the sections with 2‐mercaptoethanol. The bound SRBCs lysed when incubated with complement. The initial change that occurred after antigen injection was binding over the germinal centers and coronal regions, and heavier binding over the marginal zones that was not associated with ACP‐positive cells. In animals immunized with 1% SRBCs, these changes were seen on the third day after immunization. In animals immunized with 1% SRBCs, these changes were seen on the third day after immunization. In animals immunized with 5% or 10% suspensions of SRBCs, these changes occurred 24 hours after immunization, during dissociation of the germinal centers. In later stages there was heavy binding of SRBCs over the white pulp and over the red pulp. Binding induced by immunization was inhibited by pretreating the sections with 2‐mercaptoethanol and the bound cells lysed in the presence of complement. The results obtained suggest that IgM antibody to SRBCs appears in the germinal centers at least as early as in the marginal zone or peripheral periarterial region, and support the view that germinal centers may participate in primary antibod

ISSN:0003-276X    

DOI:10.1002/ar.1091980311

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

年代:1980

数据来源: WILEY