摘要:

AbstractThe zonula occludens (Z.O.) has been implicated as a major pathway for passive fluid movement from lateral intercellular spaces to lumen in response to an expansion of blood or fluid volume. The present study examines the Z.O. of adult rat nephrons in control and Ringer‐Locke or whole blood infused animals to determine whether varying the conditions of passive fluid movement would influence the structure of the Z.O. Rats were infused over 20 minutes with Ringer‐Locke (7% body weight) or whole blood (2.3% body weight). In the controls, 92%–94% of all Z.O. observed in proximal tubules and 100% of Z.O. from distal tubules and collecting ducts had fused outer leaflets. The approximate linear extent of the Z.O. was 140 Å for proximal tubules, 2,500 ÅR for distal tubules and 3,000 ÅR for collecting ducts. There was no significant difference in any of these values following the infusion with either Ringer‐Locke or whole blood. We conclude that expansion of blood or fluid volume causes no detectable alteration in the fine structure of Z.O. under the conditions used in the pre

ISSN:0003-276X    

DOI:10.1002/ar.1091860202

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

年代:1976

数据来源: WILEY

摘要:

AbstractDuring the course of gestation, a large amount of iron is transferred rapidly and unidirectionally from mother to fetus across the placenta. It has been postulated that one of the first steps involved in placental iron transfer involves binding of the maternal transferrin‐iron complex to the surface of the placenta and the subsequent removal of iron and release of transferrin back into the maternal circulation. To determine if transferrin is present on the surface of human placental villi, two different immunocytochemical methods have been used: (1) an unlabeled antibody, peroxidase‐antiperoxidase (PAP) method utilizing rabbit antiserum to human transferrin, goat anti‐rabbit IgG and rabbit peroxidase‐antiperoxidase complex or; (2) a peroxidase‐labeled antibody method utilizing goat antiserum to human transferrin and peroxidase‐conjugated rabbit anti‐goat IgG. The peroxidase was then localized by incubation in a diaminobenzidine‐hydrogen peroxide medium. Examination of the tissue in the electron microscope revealed the reaction product deposited as discrete patches or particles on the microvillous surface of human syncytial trophoblast. Controls using non‐immune serum or an antiserum adsorbed with purified human transferrin showed no reaction product on the surface. The results provide morphological confirmation for the presence of transferrin on the surface of human syncytial trophoblast lining the mate

ISSN:0003-276X    

DOI:10.1002/ar.1091860203

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe bone marrow contains branching vascular sinuses lying in a fibroblastic stroma which supports hematopoiesis. This paper describes the stroma and vascular sinuses by scanning and transmission electron microscopy and in freeze‐fracture etch replicas in normal rat femoral marrow and in rats made eosinophilic by larvae of trichinella spiralis.The stroma consists primarily of reticular cells which ensheath sinuses as adventitial cells and branch into the surrounding hematopoietic space. They form a spongework on which hematopoietic cells are arranged. Erythroblasts, clustered into islets, and megakaryocytes lie just outside sinuses. Granulocytes, until the metamyelocyte stage, lie in the midst of the hematopoietic cords. Lymphocytes, monocytes and likely stem cells, are clustered about arterial vessels. Macrophages occur throughout the marrow. Fat cells occur adventitial to vascular sinuses and appear to be reticular cells which accumulate fat.Processes of reticular cells closely envelope hematopoietic cells or protrude into them. Reticular cells contain rough ER and are likely fibroblastic. The argyrophilic reticular fibers of the marrow are, however, slender and scanty. Reticular cells are rich in filaments and they may contain many microtubules. They are not phagocytic and possess few lysosomes. The reticular cell cover of a vascular sinus is lifted away as maturing hematopoietic cells approach the sinus, preparatory to crossing the endothelium and entering the circulation. Maturing granulocytes often show microvilli on reaching the basal endothelial surface.The level of eosinophils in the marrow may increase from approximately four to more than 20% after injection of trichinella larvae. Close distinctive association of reticular cells and eosinophils are marked.Reticular cells provide a physical spongework on which hematopoietic cells are supported. But I postulate that they also trap and induce differentiation of hematopoietic stem cells, and sort the differentiating hematopoietic cells into characteristic locations in their spongewor

ISSN:0003-276X    

DOI:10.1002/ar.1091860204

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

年代:1976

数据来源: WILEY

摘要:

AbstractMonosodium glutamate was administered daily on days 5 through 10 postnatally at a dose of 2.5 mg/gm body weight. Counts of remaining perikarya in the arcuate nucleus of adult mice indicated approximately an 80% decrease in the number of perikarya. The arcuate lesion resulted in endocrine deficits; reproductive capacity was reduced, animals were smaller in stature and obese, and the weights of the anterior pituitary, ovaries and testes were significantly decreased while adrenals were unaffected. Light microscopic studies revealed no significant changes in thickness or general histological appearance of the median eminence. At the electron microscope level, there were no alterations in the number of nerve terminals or dense core vesicles per unit area in the contact zone. These observations suggest that afferents to the median eminence from the arcuate nucleus may form a relatively small portion of its total nerve terminal population.

ISSN:0003-276X    

DOI:10.1002/ar.1091860205

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of the monosodium glutamate (MSG) induced lesion of the arcuate nucleus on catecholamines in the arcuate nucleus and median eminence of the mouse hypothalamus was determined using the Falck‐Hillarp histofluorescence technique. The number of fluorescent perikarya in the arcuate nucleus of treated animals was decreased approximately 60%; the fluorescence intensity of surviving neurons was notably reduced. These changes were accompanied by a reduction in the intensity of fluorescence in the median eminence. Pretreatment of control and MSG‐lesioned animals with a monoamine oxidase inhibitor (pargyline) greatly increased fluorescence in the median eminence and arcuate nucleus of both groups. However, the number of fluorescing perikarya of the arcuate nucleus of the normal pargyline treated group far exceeded that of the pargyline MSG animals. It is concluded that neonatally administered MSG caused destruction of a large number of dopaminergic arcuate perika

ISSN:0003-276X    

DOI:10.1002/ar.1091860206

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

年代:1976

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091860207

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

年代:1976

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091860201

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

年代:1976

数据来源: WILEY