摘要:

AbstractThe region of epithelial apposition with a tooth surface is the site of an unusual stratified integument, the junctional epithelium, which combines tight attachment to the tooth, cell turnover, tissue permeability, and epithelial versatility into the first line of defense against periodontal destruction by oral pathogens. To better understand the structure and function of the junctional epithelium we have reviewed its developmental and cell biology, and undertaken a multidisciplinary analysis of its composition in the pig, an omnivore whose dietary and dental development and occlusion patterns are similar to the human condition, and which, because of its size, is more readily amenable to experimental manipulation. The porcine junctional epithelium was also compared with this well‐described epithelium in the rat. Morphological analyses by light microscopy and scanning and transmission electron microscopy showed the porcine junctional epithelium and epithelial attachment were similar to that in the rat except that apically, extracellular matrix lamellae associated with the internal basal lamina were more complex, and more coronally there was extensive layering of a dental cuticle‐like material. Biochemical analysis of the porcine junctional epithelium by dissociative extraction and SDSPAGE revealed the presence of some proteins not present in gingival epithelium. Together, these studies show that the porcine junctional epithelium has predictable morphological and biochemical features which establish the pig as an advantageous model to study the basic and clinical biology of this unique epithelium. © 1994 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092380102

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe neovascularization of the rabbit phallus at ages between prenatal days 15 and 21 was investigated by light‐ and electron microscopy, computer‐aided light microscopic reconstruction, and immunocytochemistry. The phalli are embedded by an abundance of mesenchymal cells, which are in contact with the neighboring ones or with the endothelial lining of growing capillaires. They often form solid cell cords that eventually make contact with the growing capillaries. The computer‐aided reconstruction of the serial light micrographs reveals that these cell cords are involved in connecting the adjacent capillaries. The incorporation of such mesenchymal cell projections into the endothelial lining, occasionally conjugated with simple attachement devices, is frequently observed by transmission and scanning electron microscopy. The contact areas between the mesenchymal and endothelial cells show immunoreactions of fibronectin.These results indicate the successive transformation of mesenchymal cells to endothelial cells of the growing capillaries. As endothelial cells of the growing capillaries show mitotic proliferation, such vasoformative mesenchymal cells seem to be involved in the acceleration of the neocapillarization of the rabbit phallus. Fibronectin actively produced in the mesenchymal cells may participate in their migration and the mechanical linkage with the endothelial cells. © 1994 Wiley‐L

ISSN:0003-276X    

DOI:10.1002/ar.1092380103

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

年代:1994

数据来源: WILEY

摘要:

AbstractAll known bone‐derived osteoinductive factors have been isolated from endochondral (EC) bones and all initiate bone induction via EC ossification. However, to date no attempt has been made to isolate comparable factors from bones which form initially and completely via intramembranous (IM) ossification. The purpose of this work was to isolate osteoinductive proteins from IM bones. To accomplish this, we extracted proteins from bovine frontal bone matrix (intramembranous origin) using methods previously described for endochondral (EC) bone matrix (i.e., femur). Bone powder (<1 mm) was decalcified and proteins extracted with 4 M guanidine hydrochloride. Ultrafiltration was used to isolate and concentrate a 10–100 kilodalton (kDa) fraction, upon which heparin‐Sepharose (HS) affinity chromatography was performed. HS‐binding (HS‐B) and non‐binding proteins (HS‐NB) were lyophilized with bovine type I collagen (Vitrogen) to form pellets which were implanted subcutaneously in rats. Radiology as well as brightfield, fluorescent, and polarizing microscopy were used to assess the formation of ectopic bone at the site of pellet implantation. In this report we demonstrate that a heparin‐Sepharose binding, osteoinductive factor can be extracted and partially purified from bovine intramembranous bone matrix. This factor has a different sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE) banding pattern than a comparable osteoinductive/chondroinductive factor isolated from EC bone. © 19

ISSN:0003-276X    

DOI:10.1002/ar.1092380104

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

年代:1994

数据来源: WILEY

摘要:

AbstractUsing an agarose gel culture system, the response of adult human chondrocytes to prolonged exposure of ascorbic acid was evaluated using histochemical, immunocytochemical and morphological techniques. The response of these cells to ascorbic acid was different from those previously reported in the literature. Many chondrocytes branched within the agarose gel with continued exposure to ascorbic acid while other chondrocytes maintained a round configuration typical of chondrocytes in vivo. Fibronectin and type I collagen were closely associated with the cell processes of the branching cells. Type II collagen and an alcian blue‐staining matrix were associated with the rounded cells but not with the branched cells. These data suggest that the chondrocytes are able to express both dedifferentiated and redifferentiated phenotypes with ascorbic acid under these culture conditions. In addition, human chondrocytes were cultured in a collagen gel and began branching within 1 hour of culture. It is possible that an accumulation of type I collagen in the pericellular matrix of ascorbic acid treated cultures may enhance and explain the branching seen in these cultures. Studies by others have indicated that ascorbic acid may enhance, reduce, and/or modify the cartilage matrices produced by chondrocytes. These controversial reports in the literature are presumably due to variations between species and the culture methods employed. © 1994 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092380105

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

年代:1994

数据来源: WILEY

摘要:

AbstractA healthy, pregnantDiceros bicornis(No. 29455), with histologically normal but relatively large kidneys containing a correspondingly large number of nephrons, died suddenly from an injury. Renal lobation was studied partly from serial transverse cuts across the kidney. The fibromuscular pelvic conduits, which are a craniocaudal bifurcation of the ureter, are associated with prominent longitudinally disposed paraconduital veins which anastomose with the interlobar veins. The arcuate veins open widely into the paraconduital veins. The latter drain into the major tributaries of the renal vein at the renal sinus. The interlobar arteries enter the parenchyma through the interlobar septa. These arteries release internal perforator branches, through the septa, which pass to the corticomedullary border, branch along that border as arcuate arteris, and release cortical branches centrifugally. All these branches give off twigs to the glomeruli.Relative renal mass of mammals is inversely proportional to their adult body mass. This is indicated by a regression line which includes rhinoceroses.D. bicornisNo. 29455, accordingly, has exceptionally large kidneys.The mesonephros of the 75 mm fetus ofD. bicornishas mature glomeruli and tubules. The metanephros has pelvic conduits, paraconduital veins, but, as yet, no medullary loops. © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092380106

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

年代:1994

数据来源: WILEY

摘要:

AbstractLocalization of non‐specific esterases, Cu‐Zn superoxide dismutase and dehydropeptidase‐I, in rat lung was investigated enzymecytochemically or immunohistochemically. Esterase was demonstrated in Clara cells, type II pneumocytes, and septal cells (or vitamin A‐storing lung cells), to a somewhat lesser extent in type I pneumocytes and ciliated epithelial cells of the bronchioles, and to a minor extent in interstitial fibroblasts of the alveolar septum. Large amounts of esterase reaction product were deposited in the rough endoplasmic reticulum and the nuclear envelope in Clara cells, type II pneumocytes, and septal cells, in addition to smaller amounts in other organelles. No reaction product was found in macrophages (histiocytes) in alveolar septi and alveolar macrophages, except for the primary lysosomes or phagolysosomes and trace amounts in the Golgi vesicles, and none in endothelial cells of alveolar blood capillaries, except for primary lysosomes. Immunolocalization of Cu‐Zn superoxide dismutase was generally limited to a particular area of Clara cells. A constriction occurred in the apical cytoplasm of Clara cells between an immunoreactive dome‐like protrusion and the non‐immunoreactive cytoplasm of the supranuclear area, and the dome‐like protrusion appereared to be pinched off in a ball‐like or oval from. Immunolocalization of dehydropeptidase‐I was demonstrated in a dome‐like protrusion or supranuclear area of Clara cells or throughout the cytoplasm and in the surface plasma membrane of mesothelial cells. The presence of these enzymes in Clara cells suggests a contribution to the detoxification system of the lung, together with cytochrome p‐450‐dependent monooxygenase system

ISSN:0003-276X    

DOI:10.1002/ar.1092380107

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe have used intratracheal instillation of bleomycin in rats to study the microanatomical changes of blood vessels associated with lung fibrosis. Bleomycin is a toxic cytostatic drug employed in classical models of lung fibrosis. Wistar rats were submitted to intratracheal injection of 1.5 units of bleomycin and sacrificed 2.5 months later, a timing when marked fibrosis of the lung is observed. We casted the vascular tree of the rat lungs by perfusion with a methacrylate resin. These caste were studied by scanning electron microscopy. Lung tissue was also studied by light microscopy and thin section electron microscopy. The major vascular modifications observed in the bleomycin‐treated rats were: (1) neoformation of an elaborate network of vessels located in the peribronchial domains of the lung, and (2) distortion of the architecture of alveolar capillaries. By light microscopy, it was clear that the newly formed vascular network was located in regions of fibrosis (which in the resin casts were digested away). These neoformed vessels appeared to originate from bronchial arteries. Thin section electron microscopy revealed that endothelial cells of the neoformed vessels were plump, presented large nuclei, and showed numerous pinocytotic vesicles that were also observed in subendothelial pericytes. The alveoli of the bleomycin‐treated rats were heterogeneous in size and shape in contrast with the homogeneity of alveoli of control animals. The alveolar capillaries of fibrotic lungs appeared to occupy a larger volume of the alveolar wall than alveolar capillaries of control rats. Our findings indicate that lung fibrosis encompasses marked changes of the vascular system, namely, the neoformation of vessels and the rearrangement of alveolar capillaries. These structural changes suggest that fibrotic transformation of the lung is associated with the local generation of angiogenic stimuli. © 1994 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092380108

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe formation of new capillaries from the rat femoral vein was specifically explored to assess whether venous vessels of this caliber may participate in the process of angiogenesis. Prostaglandins of the E series (PGE1 and PGE2) were administered into the soft connective tissue surrounding the rat femoral vessels as angiogenic inducers. In these conditions, between 2 and 7 days, a great number of new capillaries were observed in the media of the femoral vein, arising from the endothelial cells (EC) in the intima. The events of the capillary growth from the femoral vein included EC activation, local degradation of the basal membrane followed by migration and proliferation of EC, solid sprout formation with posterior canalization, development of a new basal membrane, and appearance of pericytes around the new capillary. Although numerous vascular buds were also observed arising from the small venules and capillaries in the periadventitial tissues, they were separated at first from those in the media of the femoral vein by the venous adventitia. Later, connections were observed between both newly formed microcirculations. The present study shows the capacity of PGE1 and PGE2 in the extravascular position of inducing capillary sprouting from veins. Furthermore, the observations provide greater evidence that vessels with characteristics similar to those of the rat femoral vein may contribute to angiogenesis, on occasion with an intense neovascularization. This fact may be of interest for the establishment of a functional circulation after angiogenesis by anastomoses of the new capillaries with those arising from pre‐existing vessels of greater caliber than the venules. © 1994 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092380109

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe macrocirculation in the head of three air‐breathing species ofChannawas examined with the aid of vascular corrosion replicas and a scanning electron microscopic study was conducted on the pseudobranch, choroid gland and lentiform body. Two facultative air‐breathing murrles,C. punctataandC. gachua, and one obligate air‐breather,C. maruliuswere examined. In all three, the air‐breathing organs (ABO) and systemic circulations were in‐parallel, and both were in‐series with the branchial circulation. Efferent branchial arteries from the first and second gill arches formed the arterial supply to the ABO, whereas the third and fourth arch efferents perfused systemic tissues. Postbranchial blood from the second gill arch also entered the systemic circulation directly via a shunt from the efferent branchial artery to the lateral aorta and via hypobranchial arteries. Vascular specialization to prevent mixing of oxygenated ABO venous and deoxygenated systemic venous blood was evident in arterial, but not venous circuits. Pseudobranchs ofC. gachuaandC. punctataare tri‐lobed, inC. maruliusthey have numerous lobules. Pseudobranch lamellae are wider and shorter along the axis of blood flow than gill lamellae and folded perpendicular to this axis. Pseudobranch lamellae appear to be modified to minimize their epithelial surface while retaining an extensive vascular endothelial‐pillar cell surface area, counter‐current amplification is also possible. The choroid gland is an extensive planar counter‐current capillary rete. The lentiform body of the eye is a globular capillary rete but there is no evidence of a counter‐current circulation. The choroid and lentiform rete may have distinct physiological functions.

ISSN:0003-276X    

DOI:10.1002/ar.1092380110

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

年代:1994

数据来源: WILEY

摘要:

AbstractSnakehead fish of the genusChannahave well‐developed air‐breathing organs (ABO) yet retain their gill arches for respiratory and non‐respiratory functions. Alterations in the macrocirculation accompany inclusion of the ABO and appear to enhance gas exchange efficiency (Munshi et al., 1994. Anat. Rec. 238:77–91). In the present study, the microcirculatory anatomy of gill and ABO from two facultative air‐breathingChanna, C. punctataandC. gachua, and one obligate air‐breather,C. marulius, were examined in detail using scanning electron microscopy (SEM) of vascular corrosion replicas and fixed whole‐sectioned tissue. The results show that the circulation in the filaments from the first, second, and third gill arches is similar to that found in water‐breathing teleosts. Fourth gill arch microcirculation ofC. punctatais not different from the other three, whereas inC. marulius, it has been greatly modified into a network of low‐resistance vascular shunts, although remnants of an intralamellar filamental microcirculation remain. The vascular shunts are formed from extensions of afferent and efferent lamellar arterioles and the complete, or nearly complete, loss of a lamellar sinus. The vasculature of the ABO has been highly modified in all species into a coiled‐spiral capillary network with a constricted aperture guarding a dilated capillary dome at the epithelial surface. Microvilli are found congregated on the aperture endothelium ofC. punctatabut they are virtually absent fromC. maruliusendothelium. Less than 15% of the ABO capillary surface appears to face the epithelium and thereby contributes directly to gas exchange. These findings suggest that the microvascular modifications observed inChannaentail more than a simple increase in the contact surface between ABO vessels and air and they may serve other unknown physiological functions. ©

ISSN:0003-276X    

DOI:10.1002/ar.1092380111

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

年代:1994

数据来源: WILEY