摘要:

AbstractIn the present study we describe the time of appearance and morphological differentiation of specialized epithelial cells in human fetal small intestine (SB). Proximal and distal SB from 36 nonviable fetuses was studied by light and electron microscopy. During the 9‐ to 10‐week period, villi lined by simple columnar epithelium replaced the stratified epithelial lining which was two to six cell layers thick. During this transition, distinctive junctional complexes and a single secondary lumen were identified in the deeper layers of stratified epithelium, and there was evidence of cellular degeneration of some superficial cells. Oligomucous and mature goblet cells were present in both the stratified and simple columnar epithelium. Crypt formation began proximally at 10 to 11 weeks and, within a week, crypts lined by undifferentiated crypt cells (UCC) could also be identified in the distal SB. These cells resembled adult UCC's except for the presence of large aggregates of glycogen, and the absence of large adult‐type secretory granules (SG) until 16 weeks. At all ages SG's were smaller and less numerous than in adults. Paneth cells appeared with crypt development at 11 to 12 weeks. Unlike adult Paneth cells their SG's were structurally heterogeneous and frequently had cores with halos of differing density. Caveolated or tuft cells with dense bundles of microfila‐ments extending from microvilli into apical cytoplasm, apical granules, occasional caveolae, and a microvillus membrane denser than that of adjacent cells were identified by 16 weeks. Putative microfold (“M”) cells were seen in the distal SB of a 17‐week fetus. These cells had an unusual apical border with irregular projections, many small membrane bound vesicles in the cytoplasm, and were in direct contact with underlying lymphoid cells. The glandular cells of Brunner's glands at 14 to 15 weeks resembled those of

ISSN:0003-276X    

DOI:10.1002/ar.1091910302

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

年代:1978

数据来源: WILEY

摘要:

AbstractRapid collagen breakdown in the postpartum rat uterus is accompanied by rising collagenase activity (Jeffrey and Gross, '70) and a transient infiltration of the stroma by heterophils, eosinophils, monocyte‐macro‐phages, lymphocytes, and plasma cells (Padykula and Campbell, '76), cells usually associated with inflammatory response. This uterine catabolism is initiated soon after birth while blood estrogen and progesterone levels are low. To investigate the hormonal factors involved in regulation of this postpartum stromal differentiation, we analyzed the cytological effects of experimentally elevating progesterone and estradiol levels in the peripartum period by following the protocol of biochemical experiments that have demonstrated inhibition of collagenase activity by progesterone (Koob and Jeffrey, '74) and estradiol (Ryan and Woessner, '74).Prolonged gestation (progesterone, 10 mg/day starting on day 19 gestation) was used as a condition to prevent the prenatal drop in blood progesterone; this treatment was the most effective in blocking postpartum stromal differentiation. It preserved the state of prepartum uterine differentiation and most importantly it prevented monocytic‐macrophagic conversion. Progesterone (40 mg/day) given at birth delayed but did not block stromal differentiation during the first 48 hours; by 72 hours collagen loss was extensive in both control and progesterone‐treated rats and numerous macrophages were present. Estradiol (100 μg/day) given at birth caused a greater delay in stromal differentiation than progesterone given at birth; for approximately 48 hours the number of eo‐sinophils, heterophils, and macrophages was less than normal. By day 3 the number and distribution of the macrophages resembled that of the day 1 control uteri. Overall these experiments indicate that the low estrogen and progesterone levels at birth are essential for normal stromal regression. Since these transient cells originate from the blood, the temporal pattern of their emigration into the uterus may be under hormonal control. Experimental disturbance of this pattern influences the course of collagen

ISSN:0003-276X    

DOI:10.1002/ar.1091910303

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe developing innervation of the chick eye has been studied using catecholamine histofluorescence. The innervation of the pupillary dilator by the superior cervical ganglion begins on day 13 of incubation when fluorescent axons can be seen in the ciliary zone circumscribing the dilator. On day 14 a few processes are seen to branch from this band into the dilator. The number of processes in the dilator increases on days 15 and 16. After day 16 there is a reorganization of the fibers radially accompanied by a moderate increase in the number of processes. In addition, a group of fluorescent cells can be seen in the choroid adjacent to the ciliary body. These cells are bipolar at day 9 and become multipolar by 12 days of incubation. These cells contribute to a fluorescent plexus of processes in the choroid which stops abruptly at the border of the choroid and ciliary zone. It is thought that they represent a terminal sympathetic ganglion receiving preganglionic input from the carotid nerve.

ISSN:0003-276X    

DOI:10.1002/ar.1091910304

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

年代:1978

数据来源: WILEY

摘要:

AbstractA technique is described, employing polyester as the injection material, for preparing a casting of all cardiac vessels or of arteries or veins separately. This technique was used in 10 bovine and 40 fresh human hearts.The technique is simple, rapid, economical and the required equipment is available in the average laboratory. The extent of vascular penetration is controlled by the viscosity of the polyester solutions, some of which at a certain density can penetrate through the net of capillaries with an injection pressure of no more than 220 mm Hg.Our technique does not require any special handling of the heart and it makes no difference to the quality of the casting whether the blood is drained or flushed from the vessels prior to the perfusion.There is no noted shrinkage or crumbling of our specimens stored at room temperature. The heart size, configuration and the anatomical relationship of the cardiac vessels are preserved without the need for casting cardiac chambers. The injection materials are cheap, easily transported and can be stored without special care. Injection, solidification and corrosion are carried out at room temperature.

ISSN:0003-276X    

DOI:10.1002/ar.1091910305

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

年代:1978

数据来源: WILEY

摘要:

AbstractReserpine has been demonstrated in previous studies to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of bats and this effect has been attributed to mediation by the sympathetic nervous system. The present study was done to evaluate the species specificity of this action of the drug. Reserpine caused lipid droplet accumulation in cardiocytes of guinea pigs and mice. However, in contrast to the action of the drug in bats, this action of reserpine in guinea pigs and mice could not be antagonized by chemical sympathectomy with 6‐hydroxydopamine or by treatment of animals with phenoxybenzamine, atropine or hexamethonium. Like reserpine, fasting for as little as 24 hours induced lipid droplet accumulation in cardiocytes of guinea pigs and mice. This effect also could not be prevented by treatment with 6‐hydroxydopamine indicating that the sympathetic nervous system was not involved in its mediation. Force‐feeding guinea pigs given reserpine prevented the accumulation of lipid droplets normally induced by this drug. It is concluded that the lipid droplets accumulation in the hearts of guinea pigs that follows administration of reserpine is not due to a direct cardiotoxicity of the drug but is secondary to the failure of drug‐treated animals to eat. Since the autonomic nervous system appears to mediate reserpine's cardiotoxicity in bats, the species difference revealed by these experiments probably results from an underlying physiological difference in the nervous systems of these

ISSN:0003-276X    

DOI:10.1002/ar.1091910306

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

年代:1978

数据来源: WILEY

摘要:

AbstractFusing and non‐fusing regions of neural folds from mouse embryos were examined during neurulation for the distribution of extracellular macromolecules (surface coats) prior to and at the time of closure. Ruthenium red staining of 10th day ICR/DUB mouse embryos was used to detect the distribution of surface coat material. Light microscopic examination of fusing and non‐fusing regions in the midbrain, hindbrain, and spinal cord showed a consistent increase in ruthenium red positive material immediately prior to closure. Heavy deposits of positive staining material were present along apical neural fold borders and overlying ectoderm cells. This staining pattern was consistent in the three regions examined, but the pattern of initial contact between opposing neural folds differed. In mid‐ and hindbrain areas contact was initiated by overlying ectoderm, whereas in spinal cord regions contact was first established by neuroepithelial cells. Once contact between opposing neural folds was initiated a decrease in stainable material was obs

ISSN:0003-276X    

DOI:10.1002/ar.1091910307

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of the local anaesthetic Marcaine on muscle and non‐muscle cell types was examined using an in vitro assay. Each of the cell types examined (myotubes, myoblasts, fibroblasts and liver parenchyma) expressed morphological alterations when incubated in Marcaine‐medium. Myotubes were the most sensitive of the cells studied and exhibited several pronounced membrane structural changes after short incubation periods in Marcaine‐medium. The toxic effects of Marcaine were irreversible and the myotubes continued to degenerate despite being placed in fresh medium. Myo‐blasts and non‐muscle cells, however, demonstrated a rapid recovery when removed from the Marcaine‐medium. Since Marcaine is thought to compete with Ca++for specific sites on cell membranes, it is proposed that the differential effects which were observed are dependent upon the level of calcium related activities being carried out b

ISSN:0003-276X    

DOI:10.1002/ar.1091910308

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

年代:1978

数据来源: WILEY

摘要:

AbstractSatellite cells in rat muscles were studied by freeze‐fracturing. They were found not to be fusiform but to have several narrow projections embedded in grooves of the muscle fibre membrane. Short projections of the muscle fibre covering the outer face of the satellite cells were observed as well. In the P‐face of the cell membrane of satellite cells, membrane particles and caveolae were less frequently seen than in the P‐face of the muscle membrane. Thus the surface of the satellite cells looked more smooth than that of the muscle fibres. Junctions between muscle fibre and satellite cell were not found. The presence of cytoplasmic extensions of satellite cells may suggest that these cells are m

ISSN:0003-276X    

DOI:10.1002/ar.1091910309

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

年代:1978

数据来源: WILEY

摘要:

AbstractWhite adipose tissue was obtained from the mesentery, epididymis, omentum and subcutis of rats which were fed, fasted or fasted and then refed. Tissue samples were prepared using the glyoxylic acid method to detect adrenergic nerves by fluorescence histochemistry. Other tissue samples were fixed with an aldehyde solution containing sodium molybdate which is specific forcatecholamine granules in nerve terminals. Thin and serial thick sections (0.25–0.5μm) were viewed with a conventional electron microscope and with the high voltage electron microscope. With fluorescence microscopy it was found that most of the blood vessels except veins and venules were richly innervated. The most extensive branching of nerves down to the capillary level was found in the mesentery and epididymal fat of fasted‐refed rats. Relatively few adipocytes appeared to be innervated. With electron microscopy, nerve terminals were found distributed with most blood vessels including capillaries, and with some adipocytes. Only 2‐3% of all adipocytes were innervated by adrenergic nerves. It is suggested that in the adipose tissue sites studied the major adrenergic innervation is mainly for the supply of blood v

ISSN:0003-276X    

DOI:10.1002/ar.1091910310

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe growth of the pelvic fin bud has been studied with the SEM along with the characteristics of the pseudoapical epidermal ridge which occupies the free margin of the bud. SEM revealed fluffy protuberances in many of the epidermal cells, distinguishing the fin bud territory from adjacent areas. When the pseudoapical ridge appears, all the cells show this feature but their relative number decreases and these cells, termed the “tassel cells,” are finally restricted to the base of the fin bud. This particular surface structure of the superficial cells may be unique to the fish, since it has not been heretofore reported in SEM studies of tetrapod limb

ISSN:0003-276X    

DOI:10.1002/ar.1091910311

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

年代:1978

数据来源: WILEY