摘要:

AbstractThis study concerns the size and shape of the ureteral lumen and an assessment of its enlargement during peristalsis. To stop the action of the living dog ureter, it was flooded with isopentane close to its freezing point (− 160° C). The ureter remained frozen until completion of all technical procedures. Photographs of the cut end of active ureters also provided evidence of its luminal characteristics and a movie was achieved of its continuous action. The totally collapsed lumen is stellate in form, epithelial surfaces being in virtual contact. As the lumen opens the points of the stars are last to go, but a square shape and finally a circle result. In a typical experiment, the collapsed lumen had a cross sectional area of 0.12 mm2, enlarging to 2 mm2in diuresis. This × 17 enlargement occurred over a 3 cm length of the peristaltic wave. Enlargement of the lumen is largely accommodated by thinning of the muscle coats and attenuation of the mucous membrane, there being relatively little gross enlargement of the total segment.Direct photography of the cut end of the proximal segment of the ureter completely confirms the section stud

ISSN:0002-9106    

DOI:10.1002/aja.1001330302

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

年代:1972

数据来源: WILEY

摘要:

AbstractAbsence of membranes from the secretion granules of the acinar cells of the submaxillary gland of the mouse had led to speculation concerning mechanisms of secretion of these cells. By means of rapid perfusion fixation, smooth membranes have been identified around the secretion granules, and the mode of secretion proves to be similar to that of the other exocrine glands. The evidence suggests that potent membranolytic agents of unknown nature, capable of rapidly destroying the membranes are present in these secretory granules.

ISSN:0002-9106    

DOI:10.1002/aja.1001330303

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe fine structure of ultimobranchial bodies in the rat has been studied from the fifteenth to the twentieth day of gestation. At 15 days, the ultimobranchial bodies were still separated from the median thyroid primordium by connective tissue. Their lumina were filled with cellular debris and their thick walls were made up of one type of cell in which rough‐surfaced endoplasmic reticulum was scanty. Early in the sixteenth day, cell cords from the median thyroid primordium came in direct contact with the ultimobranchial bodies; no basal lamina separated them. At 17 days the walls of the ultimobranchial bodies were composed of C cells, glycogen‐rich cells and cells that were poor in rough‐surfaced membranes and glycogen. At 18 days three types of cells were present in cell cords in direct contact with the ultimobranchial bodies: C cells, glycogen‐rich cells and follicular cells. The first two cell types had migrated from the ultimobranchial bodies while the follicular cells had originated from the median primordium. In the same cell cords, follicular cells containing glycogen granules were interpreted as being an intermediate stage between glycogen‐rich cells and true follicular cells. In follicular cells of the isthmus region, which presumably originate from the median primordium alone, glycogen granules were not observed after the fifteenth day of development. It is concluded that C cells and few follicular cells are of ultimobranchi

ISSN:0002-9106    

DOI:10.1002/aja.1001330304

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

年代:1972

数据来源: WILEY

摘要:

AbstractImplantation in the ferret occurs during the 24 hours between 12 and 13 days post coitus. The thinned zona pellucida is disrupted irregularly along the lateral aspects of implantation chambers. Some of the trophoblastic cells enlarge and develop into plaques of syncytium. Protoplasmic projections from these syncytial plaques intrude between adjacent uterine luminal epithelial cells to which the syncytium is adhering. Interesting ectoplasmic pads from the syncytial trophoblast indent the uterine epithelial cells prior to adhesion, and there are ectoplasmic regions where trophoblast cell membrane is closely applied to uterine cell membranes at all sites of epithelial penetration. Intrusion of trophoblast between uterine luminal epithelial cells is apparently the major mechanism of epithelial penetration in the ferret.

ISSN:0002-9106    

DOI:10.1002/aja.1001330305

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

年代:1972

数据来源: WILEY

摘要:

AbstractElectron microscopic examination of the livers of two teleost fishes, the zebrafish (Brachydanio rerio) and the mosquito fish (Gambusia affinis), indicates that they are morphologically similar to each other in most aspects but different in several ways from other teleosts which have been described. The perisinusoidal space of Disse is greatly reduced in relation to other vertebrates, and is represented by plasmalemmal folds in the hepatocytes apposed to the sinusoidal endothelium. There are desmosomal connections between hepatocytes and those mesothelial cells adjacent to the pancreas. Other characteristics include lack of basement laminae throughout and accumulations of fine filaments within the hepatocytes parallel to the extracellular canaliculi. Intracellular canaliculi are incompletely surrounded by such filaments.In fish which have been starved, or in gravid females, an expected loss of glycogen is accompanied by a concentration of rough endoplasmic reticulum and elongation of mitochondria, which in starved fish may be pleomorphic. In either condition, the liver undergoes severe atrophy.

ISSN:0002-9106    

DOI:10.1002/aja.1001330306

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe geniohyoid, anterior belly of digastric, mylohyoid, and genioglossus muscles of 20 human subjects were studied electromyographically to determine the temporal relationships of their activities during the act of swallowing. Although the firing order of the four muscles varied within the same subject, the best estimate of the “true” firing sequence was established for each of the 18 subjects who provided statistically significant data. However, no definite universal pattern could be established for the four muscles because there was great inter‐subject variability in both the duration and the sequence of activity. Therefore, at least with respect to these four muscles, each individual has his own swallowing pattern, but different people may swallow quite differently.The type of bolus (salivavswater) may influence the duration of the muscles' activity. On the other hand, posture (semi‐reclinedvssitting) did not seem to have any influence. There was no evidence to indicate that posture and/or the type of bolus are correlated with the sequence of muscular activity.The anterior belly of the digastric muscle was not active in one‐quarter of the swallows studied. When active during deglutition, all muscles had a general electromyographic pattern of one to many summations of activity separated by relatively quiet periods before and after eac

ISSN:0002-9106    

DOI:10.1002/aja.1001330307

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

年代:1972

数据来源: WILEY

摘要:

AbstractFemale Taconic Swiss mice were fed a high‐fat (28%), low‐protein (8%), hypolipotropic diet. Some of the animals received intraperitoneal injections of washed, packed red blood cells or physiological saline while receiveing the diet. Mice that received only the experimental diet for ten weeks developed a high incidence of atrial thrombosis (84%) concurrently with severe anemia (hematocrit 6.7). Saline injections did not alter these changes significantly. Atrial thrombosis was prevented in mice maintained at a normal or slightly subnormal hematocrit level with injections of washed, packed erythrocy

ISSN:0002-9106    

DOI:10.1002/aja.1001330308

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

年代:1972

数据来源: WILEY

摘要:

AbstractTissue from the central nervous system of 11 adult Sprague‐Dawley rats fixed by vascular perfusion with buffered aldehydes was used in a study of the fine structure of the pia mater. Surface tissue from the cerebral and cerebellar cortices, ventral pons, olfactory bulb, tuber cinereum, spinal cord, superior colliculus, optic chiasm, and median longitudinal fissure was examined. Variations in pial composition occurred within each of these selected areas although a basic pattern prevailed throughout.The components of the pia mater are described under three categories: pial cells, extracellular elements, and macrophages. The pial cells are the more numerous cell type, possessing long, flattened cytoplasmic processes which contain few inclusions. These cells vary in thickness in any one area and there may be from one to six distinct cytoplasmic layers. Fenestrations between pial cell processes or total absence of pial cells are occasionally encountered. Unit collagen fibrils make up most of the extracellular material of the pia. These have a major period of about 550 Å and are about 400 Å wide. Macrophages are rounded up and contain various cytoplasmic inclusions. In normal animals evidence of active phagocytosis is r

ISSN:0002-9106    

DOI:10.1002/aja.1001330309

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe source of myotube nuclei in regeneration of skeletal muscle in young rats was studied by comparing frequencies of labeled nuclei in two experiments. In a single injury experiment, multiple injections of thymidine‐H3were given during a three day period, skeletal muscle was injured 12 days later and the rats were killed four days after injury. There were almost no labeled myotube nuclei in this experiment. In a double injury experiment, thymidine‐H3was injected two days after injury, the muscle was reinjured 12 days later, and the rats were killed four days after the second injury. Half of the myotube nuclei were radioactive and most of the centrally placed nuclei in maturing muscle fibers from the initial injury were radioactive. Since nuclei at the periphery of muscle fibers, including satellite cell nuclei, would have been labeled in both experiments, whereas myonuclei were extensively labeled only in the double injury experiment, it was concluded that the myotube nuclei were derived mainly from myonuc

ISSN:0002-9106    

DOI:10.1002/aja.1001330310

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

年代:1972

数据来源: WILEY

摘要:

AbstractIn the nonhibernating animal the stress of prolonged deep hypothermia is associated with the development of circulatory symptoms like those of burn‐shock. Mast cells are sensitive to a variety of stressors, including thermal ones, and commonly react by releasing vasoactive substances that may facilitate vascular changes similar to those of burnshock. The possible role of mast cells in the complications of prolonged hypothermia was the object of this investigation.Two groups of female albino rats were subjected to 15° C total body hypothermia for 7.5 hr and then rewarmed artificially. Group I had been treated previously with compound 48/80 which depletes the mast cell content of tissues. Group II constituted controls and possessed a normal complement of mast cells.Progressive hemoconcentration was noted in both groups. However, the hematocrits of the 48/80‐treated animals were significantly lower at selected intervals than those of control animals. In addition, 100% survival of the 48/80‐treated animals was recorded in contrast to a 60% survival rate for controls. Microscopic examination of the mast cells in several tissues of additional controls suggested a loss of granule density during hypothermia and early rewarming. This investigation offers circumstantial evidence that mast cells of the rat facilitate the development of some of the deleterious effects of prolonged hypot

ISSN:0002-9106    

DOI:10.1002/aja.1001330311

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

年代:1972

数据来源: WILEY