ISSN:0003-276X    

DOI:10.1002/ar.1092080103

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

年代:1984

数据来源: WILEY

摘要:

AbstractExtracellular accumulation of a granular material that is presumed to be an organic “precursor” to mineralized enamel has been reported. This material, generally referred to as “stippled material,” was observed mainly after immersion fixation with osmium tetroxide. In studies with perfusion fixation, the presence of stippled material was inconsistent. Therefore, it appeared that the occurrence of stippled material was dependent on the method of fixation. To test this assumption, tissues were fixed by immersion in either osmium tetroxide or glutaraldehyde and by perfusion with either glutaraldehyde or a mixture of acrolein, glutaradehyde, and formaldehyde. It was found that as the quality of cellular preservation improved, the occurrence of stippled material decreased. Since no stippled material could be found in material judged to be well fixed, it was concluded that stippled material is not an extracellular precursor to mineralized enamel, but is a breakdown product resulting from poor f

ISSN:0003-276X    

DOI:10.1002/ar.1092080104

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

年代:1984

数据来源: WILEY

摘要:

AbstractAlloxan is known to induce diabetic renal changes as well as causing nephrotoxic alterations. However, no ultrastructural study has been performed to differentiate diabetic verses toxic affects of alloxan to the tubule and/or glomerulus. Therefore the present study used the “protected” kidney model to prevent one kidney from being exposed to the alloxan while allowing the other to receive the drug immediately. In all experimental animals the right renal hilum was gently occluded for 5 minutes and then released. This was performed prior to the injection of alloxan. Subsequently, the left renal hilum was occluded at the time of, and for 5 minutes after, alloxan administration (40 mg/kg i.v.). The experimental rats were divided into three groups: untreated diabetics, diabetics treated with protamine‐zinc‐insulin, and alloxantreated rats that failed to become diabetic. Three groups of controls were included: one group received an equal volume of saline diluent as the experimental rats but no clamping of either renal hilum; another group received the saline and had the left renal hilum occluded for 5 minutes; and a third group had both the right and left renal hila occluded. All animals were followed and sacrificed after 9 weeks. Endogenous creatinine clearance did not change among groups. Alloxan‐treated nondiabetic rats displayed marked interstitial nephritis in unprotected kidneys, while protected kidneys were normal. The diabetic state resulted in mesangial proliferation and focal glomerular basement membrane thickening as well as glomerular capilary endothelial abnormalities and visceral epithelial foot‐process fusion. The endothelial changes consisted of focal areas showing a reduction in the size of endothelial fenestrae. All glomerular changes were ameliorated by insulin treatment. We conclude: (1) alloxan per se is distinctly nephrotoxic; and (2) the glomerular endothelium and epithelium are involved early in the course of experiment

ISSN:0003-276X    

DOI:10.1002/ar.1092080105

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

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper aims to clarify the relationship of the dermis to epidermal ridge configuration. After fixation, human fingertip epidermis was peeled off from the dermis by alkaline treatment, and the dermal surface was observed with the scanning electron microscope (SEM). The SEM pattern of furrows, grooves, and papillae showed an exact negative fingerprint image. Papillae had various sizes and complicated shapes and were arranged continuously but irregularly on each side of the furrow. Size and shape variabilities were not dependent on the site of the fingerprint region. The papilla number tended to increase with age due to derivation of secondary papillae from the primary papilla as well as new formation of small papillae. The dermal surface exhibited some site‐specific fibrous appearance at the furrow and papilla, whereas the surface was smooth at the groove. The characteristics of the dermal surface structure as related to the epidermis can be explained by a stronger dermis‐epidermis adhesion at the furrow than at the papilla or at the gro

ISSN:0003-276X    

DOI:10.1002/ar.1092080106

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe pattern of innervation of the caudal thoracic and cranial lumbar vertebral column of the dog is described. Frozen sections stained with Schofield's silver impregnation method show that the dorsal longitudinal ligament is profusely innervated, while the anulus fibrosus contains a few nerves limited to its outermost layers; no nerves are present in the nucleus pulposus. Following injection of horseradish peroxidase (HRP) into the anulus fibrosus of the thoracolumbar intervertebral disc and subsequent removal and staining of dorsal root ganglia, the reaction product is found in ganglia as far as two segments cranially as well as caudally, demonstrating that the disc is innervated by nerves arising from several spinal cord segments. A meningeal ramus, which innervates the discs of man, could not be found by gross dissection. Dissections show each vertebral articular facet innervated by the medial branches of two contiguous spinal nerves, a pattern further confirmed by injections of HRP into facet joints with subsequent staining of dorsal root ganglia. The dorsal rami of spinal nerves often divide into medial, intermediate, and lateral branches rather than the traditionally described division into only medial and lateral branches.

ISSN:0003-276X    

DOI:10.1002/ar.1092080107

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to quantify the percent volume of actively functioning blood vessels in five dogs subjected to ligation of the left anterior descending artery and to localize catecholamine‐containing nerve terminals in the same tissue blocks. Radioactive microspheres were injected to determine the extent of flow reduction in the ischemic zone. After 1 or 3 hr of occlusion, thioflavin‐S (0.125 ml/Kg of a 4% solution) was injected intravenously 15 sec prior to removal of the heart. Tissue samples were reacted with paraformaldehyde to visualize catecholamine‐containing nerve terminals prior to embedding in paraffin. The percent volume of blood vessels labeled with thioflavin‐S was quantitated in tissue sections using a point‐counting technique in which a small dot from a video screen was projected through an image‐projecting tube and moved by computer control over the image of the fluorescent tissue. In the nonischemic zone, the mean blood flow determined by the microsphere technique was 1.29 ml/min/g ± 0.48 (SD), and the mean volume percent of thioflavin‐labeled vessels was 12.67 ± 3.30. In the ischemic and border zone areas, there was wide range of flow reduction, and there was a significant correlation between the blood flow measured with microspheres and the percent volume of thioflavin‐labeled blood vessels (R = 0.80, P<0.001). In the nonischemic zone, both blood vessels and catecholamine‐containing nerve terminals were visible; however, in the ischemic zone, few labeled vessels were seen, although nerve terminals were often present. A method has been presented here in which blood flow can be predicted microscopically in a small sample of tissue using a unique method of point counting of fluoresc

ISSN:0003-276X    

DOI:10.1002/ar.1092080108

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe morphology and permeability of tight junctions of the three major epithelial constituents of rat parotid gland–acinus, intercalated duct, and striated duct–have been examined ultrastructurally. Acinar and intercalated duct junctions (including those surrounding intercellular canaliculi) averaged two to three sealing strands, whereas striated duct junctions had five to eight sealing strands. When the permeability of the junctional complex was probed by means of a recently devised lead ion tracer technique, acinar junctions were found to be very permeable, intercalated duct junctions were somewhat permeable, and striated duct junctions were essentially impermeable to the tracer. Thus, by both morphological and tracer‐permeability criteria, acinar tight junctions appear to be “leaky.” These data provide strong evidence that, in rat parotid glands, a potential paracellular secretory pathway exists in the acinar region for the transepithelial passage

ISSN:0003-276X    

DOI:10.1002/ar.1092080109

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

年代:1984

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1092080110

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe development of immunoreactive somatostatin in thyroid C cells of dogs and guinea pigs from early fetuses to adults was investigated by the use of immunoperoxidase histochemistry and radioimmunoassay. The time of appearance and developmental patterns of immunoreactive somatostatin in the C cells were completely different in both species. In guinea pig thyroids, the somatostatin immunoreactivity appeared later than the calcitonin immunoreactivity and the number of somatostatin‐positive cells was very small during fetal periods. The somatostatin immunoreactivity rapidly increased during neonatal periods. A large population of the somatostatin cells and a high concentration of somatostatin immunoreactivity were observed in mature animals. On the other hand, in dog fetuses somatostatin immunoreactivity appeared very early, at the same time as the calcitonin immunoreactivity. The largest population of somatostatin cells was found at the stage when the primordial follicles were vigorously formed throughout whole thyroid parenchyma. At this stage almost all of calcitonin‐positive cells were also somatostatin‐positive. The somatostatin cells progressively decreased as the development proceeded, in contrast to the calcitonin cells which increased with gestational age. In postnatal dogs only a few C cells revealed the immunoreaction for somatostatin, and the concentration of somatostatin was very low. These findings suggest that the function of somatostatin in dog thyroid C cells may be different from that in guinea pig C

ISSN:0003-276X    

DOI:10.1002/ar.1092080111

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

年代:1984

数据来源: WILEY

摘要:

AbstractFetal rabbits (days 13–32), rats (days 14–22), and hamsters (days 11–15) and selected postnatal animals were examined for pulmonary macrophages or their precursors in 2‐m̈m sections stained by PAS‐lead hematoxylin (all species), electron micrographs (rabbit and rat), and cytochemical incubations for acid phosphatase (rabbit and rat), aliesterase, and N‐acetyl glucosaminidase (rabbits). All methods revealed macrophages in perinatal specimens. The appearance and distribution of these cells were compared in the different preparations to establish the reliability of PAS‐lead hematoxylin for identifying them in less developed fetal lungs, where they are less active for lysosomal enzymes the earlier the stage examined. In the sections, macrophages are seen to possess a round or indented nucleus, an irregular contour, and a deep purplish‐gray cytoplasm containing a variety of pink PAS‐stained granules, equated with heterolysosomes by ultrastructural cytochemistry. In less developed lungs, macrophages occur along with putative precursors having a more rounded outline and fewer PAS‐stained granules. In pseudoglandular lungs these precursors predominate over rather vacuolated macrophages resembling Hofbauer cells. In all three species both cell types first appear in the stroma during the bronchial bud stage and are frequently seen to divide from that time on. The earliest precursors have a relatively sparse cytoplasm which later increases in daughter cells. Hofbauer‐like cells disappear during the canalicular stage of development, replaced by macrophages and transitional forms from the more rounded precursors. In day 21 rabbit lungs, scattered stromal cells are reactive for aliesterase, and, some days later, for acid phosphatase and glucosaminidase. Free mononuclear cells are rare in airways of pseudoglandular lungs but become common later. A day or two before birth in rats, free cells range between rather undifferentiated leukocytes to typical macrophages, but cells with the macrophage's complete repertory of inclusions are seen only after birth. In the fetus, typical monocytes were not identified in either the pulmonary stroma or the airways. A replicating population of macrophage‐like cells therefore resides in fetal lungs. It is established before bone marrow is formed and, in rats, before monocytes have app

ISSN:0003-276X    

DOI:10.1002/ar.1092080112

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

年代:1984

数据来源: WILEY