摘要:

AbstractMale and female Taconic Swiss mice were fed a high‐fat (28%), low‐protein (8%), hypolipotropic diet. Intact mice and gonadectomized mice, with and without injections of estrone or testosterone phenylacetate were studied.The sex of the animals did not alter the incidence or type of diet‐induced cardiovascular lesions. During the 6–12 weeks of feeding thrombi developed in the atrial lumina of 75%–88% of intact and gonadectomized male and female mice. The only prominent decrease in the incidence of such thrombosis was in gonadectomized animals of both sexes receiving estrone where it was reduced to 6%–16%. In castrated males receiving injections of testosterone phenylacetate (Perandren) the incidence of thrombo

ISSN:0003-276X    

DOI:10.1002/ar.1091680301

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

年代:1970

数据来源: WILEY

摘要:

AbstractVarious physiological and anatomical studies have suggested that the ciliary epithelium may be under the influence of adrenergic nerve fibers. This study was undertaken in an attempt to characterize the innervation of the ciliary epithelium. Both light and electron microscopy revealed that the ciliary epithelium is only sparsely innervated. In addition, the ciliary epithelium overlies a highly vascular stroma, and the distance between the large vascular channels and the ciliary epithelium is small. These features of the stroma indicate it is structurally suited for a transport function, a fact which supports earlier reports that the elaborate membrane infoldings of the ciliary epithelium are indicative of a transport function. The discrepancy between previous descriptions of the innervation of the ciliary epithelium, demonstrating complex subepithelial plexuses of adrenergic nerve fibers, and the results of the present study may be due to the fact that the fluorescence technique used in previous studies could have labelled some other tissue component in addition to adrenergic nerve fibers. Results with orcein and aldehyde fuchsin stains indicate that the disposition of elastic fibers in the ciliary processes is similar to previous descriptions of adrenergic nerve fibers as determined by fluorescent techniques.

ISSN:0003-276X    

DOI:10.1002/ar.1091680302

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe origin of the cells which form the aortic arches in the chick embryo was determined by tracing the movements of tritiated thymidine‐labeled grafts excised from medium streak (MS) to head process (HP) stage embryos and transplanted to the epiblast, streak and endoderm‐mesoderm layers of similarly staged recipient embryos.Between the MS and HP stages, the preaortic arch cells migrate in epiblast to the primitive streak, invaginate, and move anteriorly and laterally from the streak into mesoderm; at the HP stage they are lateral to the cells which will form the anterior parts of the dorsal aortae, and medial to the heart‐forming regions. The most anterior prearch cells form the first arch and the more posterior cells form the more posterior arches. The prearch cells are closely associated during migration with the endoderm cells which will form the adjacent branchial arches and clefts.Cells which will form the posterior end of the aorta are still in the epiblast layer at the late medium streak (LMS) stage, but have moved to the primitive streak at the HP stage; they migrate from the streak into mesoderm posterior and medial to the mesoderm destined for the heart and aortic a

ISSN:0003-276X    

DOI:10.1002/ar.1091680303

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

年代:1970

数据来源: WILEY

摘要:

AbstractMature and embryonic scales of the zebrafish,Brachydanio rerio, were examined by light and electron microscopy. Each scale consists of a mineralized “osseous layer” superficially and a deeper, non‐mineralized, “fibrillary plate.” The mineralizing matrix contains randomly oriented filaments in decalcified sections, whereas the fibrillary plate is composed of orthogonally arranged lamellae of banded collagen fibrils embedded in electron dense material.Scale papillae and small scales first appear in the midbody region of fry between 0.95 and 1.14 cm long. The matrix of the osseous layer is produced prior to the fibrils of the fibrillary plate. Foci of mineral deposition appear in this matrix soon after its production, and increase gradually in number and extent. Cells surrounding the periphery of the scale are continuous with two layers of cells beneath the inner surface and with two layers extending a variable distance over the superficial surface. These “scale‐associated” cells are separated from the dermal collagen by other investing cell processes. The probable roles of these cells in scale formation are discussed and the need for further investigation of the fish scale as a mineralizing sys

ISSN:0003-276X    

DOI:10.1002/ar.1091680304

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

年代:1970

数据来源: WILEY

摘要:

AbstractInitial osteogenesis of secondary centers of ossification in the humeral head of the dog was studied with serial sections, histochemistry, radiography and vascular injections. At birth this chondroepiphysis was found to be well vascularized by a network of cartilage canals. On the second day after birth the first morphological evidence of the secondary center of ossification was seen. This was in the form of multiple foci of calcification. Each focus of calcification occurred immediately adjacent to the glomerular end of a cartilage canal and not in an avascular matrix. The capillaries of the glomerulus were modified in the process and persisted as the blood supply to the secondary center of ossification. By four days of age the individual foci had coalesced into a single larger focus of calcification. This process of ossification was found to possess morphological similarities to that occurring at the metaphyseal side of the epiphyseal plate.

ISSN:0003-276X    

DOI:10.1002/ar.1091680305

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

年代:1970

数据来源: WILEY

摘要:

AbstractTaste buds of rabbit circumvallate papillae were studied with the electron microscope at intervals from six hours to 11 weeks after section of the glossopharyngeal nerve distal to the petrosal ganglion. Nerve endings were first affected, showing degeneration as early as 12 hours and disappearing by 48 hours. Rapid loss of cells and of all buds by ten days followed. Numerous inclusion bodies within type I and type II cells were interpreted as autophagic activity in type II cells and both phagocytic and autophagic activity in type I cells. Type III cells were lost primarily by pyknosis, and phagocytized by type I cells. No clear evidence of dedifferentiation, or extrusion of dead cells, was observed.Regenerated nerves appeared beneath the epithelium at 21 days but new buds first appeared at 25 days, after nerves had penetrated the basement membrane. Intimate contact of nerves with epithelial cells appears to be a precondition for taste bud renewal. Early appearance of cells resembling basal cells (type IV) followed by relatively simultaneous appearance of type I, II and III suggest independent origins for these three types. The data support a humoral hypothesis of trophic action but do not rule out a role for impulse transmission.

ISSN:0003-276X    

DOI:10.1002/ar.1091680306

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

年代:1970

数据来源: WILEY

摘要:

AbstractTwo morphological traits of the anterior cerebellar lobe unique to the higher anthropoid primates are described, and a search for their possible origins is made among representatives of the major subdivisions of the Anthropoidea. One trait involves the gradual reduction and migration of lobule II until it ultimately becomes located upon and fused with lobule I. Hence, in the higher anthropoids, the lingula actually consists of lobules I and II combined. This reduction and migration of lobule II from its normal position places lobule III adjacent to the lingula in the location occupied by lobule II among other mammals. The second distinctive feature concerns the inclusion of the anterior cerebellar peduncle on each side into the anterior medullary velum, so that they form a continuous morphological unit, separate and distinct from the remaining components on the ventral surface. This modification is found only in the members of the Hominoidea. In addition, several observations upon certain ontogenetic changes in lobular structure are reported.

ISSN:0003-276X    

DOI:10.1002/ar.1091680307

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

年代:1970

数据来源: WILEY

摘要:

AbstractHistochemical changes were observed in the epithelium of the toad urinary bladder followingin vitroandin vivostimulation by aldosterone to determine the cell types affected by this hormone. A marked pyrinophilia was observed in comparison to control tissue affecting all cell types, as well as slight increases in cytoplasmic PAS staining within the granular cells, under both sets of conditions. An increased number of mitochondria was demonstrated with the PTAH stain within the granular cells underin vivoconditions but notin vitro.Underin vivoconditions, marked increases in the enzymes of the oxidative pathway (DPND, TPND, SDH, and cytochrome oxidase) were observed in granular cells. Enzymes of the oxidative pathway were unchanged underin vitroconditions was more intensely localized to the cell membrane and cytoplasm of all cells. Granular cells fromin vitrostudied tissue were slightly more reactive for G6PD and 6PGD than control tissue; granular cells were even more heavily reactive for these enzymes underin vivoconditions. Thus, under prolonged aldosterone stimulation, the granular cell approached the histochemical profile of the mitochondria‐rich cell. The hormone may therefore act upon the granular cell, which comprises the largest number of cells within the epithelium, as well as the mitochondria‐rich c

ISSN:0003-276X    

DOI:10.1002/ar.1091680308

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe electrical potential of the rabbit allantoic membrane is sensitive to acetylcholine, a sensitivity which can be altered or abolished by anticholinesterase compounds. Biochemical and histochemical studies indicates that acetylcholinesterase activity is present in the endodermal layer of the membrane. These findings suggest that the allantois may be a valuable model for investigations into the role of acetylcholinesterase in membrane excitability.

ISSN:0003-276X    

DOI:10.1002/ar.1091680309

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

年代:1970

数据来源: WILEY