摘要:

AbstractNormal fetuses 13‐to‐21 days of age were obtained from female Long Evans Rats maintained on a stock diet known to produce normal offspring. Cleft palate fetuses were produced from mothers fed the same diet supplemented with 100 mg of pyrimethamine per kg of diet for four days beginning on the tenth day of gestation. The heads were studied with the low‐power microscope and serial histologic sections.In normal fetuses the lateral palatine processe appeared to form the roof of the mouth by two distinct mechanisms. Palatal closure was achieved rostrally by rotation of the lateral palatine processes from a ventromedial to a horizontal position while caudally, it resulted from the fusion of outgrowths from the medial surfaces. The original free ventral edges of the lateral palatine processes in the caudal region largely underwent regression by the seventeenth day. Closure commenced in the anterior third of the palate and proceeded rostrally and caudally.In the fetuses with cleft palate induced by pyrimethamine, the lateral palatine processes were observed in various stages of rotation or transformation depending on the region of the palate examined. The narrow width of these processes suggested that the antimetabolite had suppressed their growth at a critical stage in development. The results suggested certain similarities in the mechanisms of palatal closure in rat an

ISSN:0003-276X    

DOI:10.1002/ar.1091510202

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

年代:1965

数据来源: WILEY

摘要:

AbstractBy direct ventricular puncture involving use of a micro‐pipette and water manometer the ventricular blood pressures of 81 chick embryos ranging in age from 2 to 7 days of age were obtained. The mean ventricular diastolic, systolic and mean blood pressures in millimeter of water (given in the order) were as follows: 5 ± 1.4; 21 ± 2.4 and 10 ± 1.4 in two day hearts, 10 ± 1.58; 27± 6.68 and 14 ± 14.32 in three day hearts; 14± 1.41; 39 ± 6.22 and 19± 2.39 in four day hearts; 17 ± 5.89; 63 ± 15.49 and 32 ± 12.08 in five day hearts; 5.45 ± 8.59; 74 ± 17.94 ± and 34 16.76 in six day hearts. At seven days the mean ventricular diastolic pressure was 1.33 ± 2.36 mm of water.Ventricular diastolic pressure increased from the second through the fifth days, underwent a marked drop at six days and fell to near zero at seven days of development. Since in fully developed hearts ventricular diastolic pressure approaches zero if the valves of the outflow tract are competent, the following conclusion concerning valvular action was drawn; the valvular mechanism of the outflow tract in the developing embryonic chick heart is incompetent at two, three, four and five days of development. It begins to become competent between the fifth and sixth days and attains compete

ISSN:0003-276X    

DOI:10.1002/ar.1091510203

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

年代:1965

数据来源: WILEY

摘要:

AbstractBone can be differentially staineden blocby fixing in 10% formalin, decalcifying in dilute nitric acid, and placing in an ammoniacal silver nitrate solution. The block is then infiltrated and embedded in gelatin for serial sectioning while frozen. Structures range from colorless to yellow, through different shades of brown or reddish brown, to black. This range is seen among different osteones, and even within a single osteone. Color changes within the same structure can be observed easily in serial sections. Collagen fibers, Sharpey's fibers, and assorted cell nuclei are also stained, but cement lines are not. Canaliculi usually do not stain, but occasionally stain vividly. Very darkly stained areas show little histological detail. Some of the characteristics of bone stained by this technique suggest that a relationship exists between the extent of mineralization and degree of staining. Similar features of x‐ray photomicrographs of undecalcified bone sections support such a relationshi

ISSN:0003-276X    

DOI:10.1002/ar.1091510204

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe lymphocytic tissues of normal rats were fixed in cold alcohol and embedded in paraffin. Unstained sections were examined under the fluorescent microscope. The sections were stained, thereafter, by various techniques.Peculiar “autofluorescent cells” were found at the cortico‐medullary junction of each thymic lobule, associated with lymphocytic nodules, and, in the plasmocytic medullary cords of the nodes. These cells contain numerous yellow autofluorescent granules and a few blue ones. The amount of yellow granules increases in the lymphocytic organs of pregnant rats. The granules stain positively with Sudan black B and P. A. Schiff techniques, and stain pale green with toluidin blue.Comparison reveals that the “autofluorescent cells” correspond to the “Lipid‐laden foamy cells” described by Loewenthal and Smith and to the “PAS‐positive reticulum cells” of Metcalf. Unlike Loewenthal et al. it is concluded that these cells are not arising from thymic involution. Metcalf's conclusion that these cells control thymic lymphocytopoiesis is analyzed in view of new findings and his conclusion is questioned. The development of the autofluorescent cells is shown to somehow parallel the development of post‐weaning growth and of immunity. The possible function of the autofluorescent cells in both

ISSN:0003-276X    

DOI:10.1002/ar.1091510205

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

年代:1965

数据来源: WILEY

摘要:

AbstractTwo‐hundred and eight mice were paired as parabionts, or as single controls, with normal mice on the day of weaning. Pairs were sacrificed at 4, 8, 12 and 16 weeks after pairing. Autopsies were performed, organs were weighed and microscopic examination of tissues was performed. The results show a decreased liver weight in parabiosed dystrophics with a concomitant increased liver weight in parabiosed normals. The severity of muscle lesions of parabiosed dystrophics was less than that of counterpart single dystrophics. There was no observed clinical improvemen

ISSN:0003-276X    

DOI:10.1002/ar.1091510206

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe distribution of tubular lipids and acid phosphatase activity was studied in the rat testis and in the ductuli efferentes. The results were referred to the stage of the cycle of the seminiferous epithelium. The significance of the lipids and phosphatase of the ducts was tested in animals, where excretory ducts were separated from testis for 30 to 40 days.During the acrosome phase of the old generation of spermatids the lipids first made their appearance in the cytoplasm. During the subsequent stages of the cycle (II to VIII) both the amount of lipids and the intensity of the acid phosphatase activity gradually increased, reaching a maximum in the cytoplasmic “split‐offs” of the mature sperm at stage VIII. Most of the lipids, together with phosphatase‐positive cytoplasmic granules were discarded with the spermatozoa, but a small proportion underwent phagocytosis by the Sertoli cells. During stage IX both lipid‐ and phosphatase‐positive particles moved to the periphery of the tubules as their number in the basal cytoplasm of the Sertoli cells rapidly increased. Through the stages IX to II a gradually diminishing amount of lipids and acid phosphatase activity was seen forming a peripheral ring in the tubules. A temporary rise in the Sertoli cell phosphatase activity took place at the time when the nuclei of the maturing spermatids were deep in the seminiferous epithelium (stages IV and V).Lipid droplets associated with acid phosphatase activity were present in the epithelium of ductuli efferentes of intact rats. Ductectomy caused a complete disappearance of the epithelial lipids. Simultaneously, cysts filled with degenerating spermatozoa and abundant lipids formed on the cut surface of the testis. It is concluded that the main part of the residual cytoplasm of the spermatids forms an apocrine secretion which is presumably absorbed in the ductuli efferentes and in other parts of the excretory

ISSN:0003-276X    

DOI:10.1002/ar.1091510207

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

年代:1965

数据来源: WILEY

摘要:

AbstractDuring specific phases of the luteal stage of the estrous cycle, and during early pregnancy, or following progestational administration, there is a marked mobilization of lymphoblast‐like cells in the connective tissue of the plica. These cells readily penetrate the basment membrane, and assume an intercalary position in their migration between the epithelial cells to the lumen. Progestational treatment intensifies this migration during the luteal phase of the estrous cycle in the normal animal, or induces this migration in the oviducts of the ovariectomized animal. Estrogenic treatment alone, in the ovariectomized animal, will not maintain the migration of lymphoblast‐like cells in the connective tissue of the oviduct, nor their penetration between the epithelial cells and extrusion into the lumen of the tissue. Estrogenic treatment induces a marked modification of the lymphoblast‐like cells mobilized by progestational treatment, resulting in morphological reorganization and destruction of the cells in the oviductal tissues. The morphological reorganization of the cell is noted in eosinophilic granulation of the cytoplasm, followed by fragmentation of the nuclear chromatin within the cell. The eosinophilic granulation is lost, followed by dissolution of the nuclear and cytoplasmic membranes and scattering of the chromatin material into the t

ISSN:0003-276X    

DOI:10.1002/ar.1091510208

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe morphology of the umbilical cord of the rat has been investigated in fetuses of 17,19,20 and 21 days gestation. The development and differentiation of three major features of the cord, the covering amniotic epithelium, the mesenchyme of Wharton's jelly, and the major umbilical blood vessels, were studied. At 17 days gestation, the epithelium is composed of a simple layer of flattened cells without obvious specialization and later becomes bilayered and shows considerable irregularity at the surface and at cell‐interfaces, where desmosomes are a prominent feature in the stages just prior to birth. Within the underlying mesenchyme, there is a decrease in cellularity throughout the period under study. Mesenchymal cells are characterized by the presence of a well developed endoplasmic reticulum containing an electron dense homogeneous material. Ribosomes in association with the endoplasmic reticulum are in the form of polysomal aggregates by 17 and 19 days gestation which later become less marked. Unit fibrils of collagen increase in number in the days prior to term and in later stages appear in definite bundles. In the umbilical blood vessels, there is differentiation of a muscle coat from an aggregation of mesenchymal cells. No nerves in relation to the blood vessels and no vascular supply to the umbilical cord itself could be identified in any stage of the present stud

ISSN:0003-276X    

DOI:10.1002/ar.1091510209

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

年代:1965

数据来源: WILEY

摘要:

AbstractThe effect of testosterone propionate administration on the quantity and localization of a nerve growth protein was studied in the submandibular glands of adult female Swiss mice. Testosterone treatment for 14 to 24 days resulted in an increase in the quantity of a nerve growth‐promoting protein approaching those levels found in normal untreated adult male Swiss mice. The nerve growth‐promoting protein was localized by immunofluorescent techniques in the cytoplasm surrounding the zymogenic granules of the serous tubular portions of the submandibular glands in both control and treated animals. The role played by the submandibular gland in the synthesis or storage of this factor is discus

ISSN:0003-276X    

DOI:10.1002/ar.1091510210

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

年代:1965

数据来源: WILEY

摘要:

AbstractA comparison of the soluble proteins of lens cortex and nucleus of several adult mammalian lenses, using a combination of paper and starch gel electrophoresis, revealed significant differences in the distribution of alpha and gamma crystallins. At least 2–5 gamma crystallin proteins of different molecular size were not detected in the cortex, but were found in the nucleus. These proteins correspond to the category of embryonic lens protein as defined by Francois and Rabaey ('57). Such a protein is synthesized almost entirely before birth, and thus accumulates mainly in the nucleus of the adult lens. In contrast to the mammalian lens, the adult chick lens contains only one protein which is present in significantly lower concentration in the cortex when compared with the nucleus. This protein is the major beta crystallin component, which is first detected during embryogenesis, at the time of appearance of the primary lens fibers. The reason for the decreased synthesis of these proteins in adult life remains to be elucidated.Differences were also noted in the relative concentration of alpha crystallin in mammalian lens nucleus and cortex. The smaller of the two alpha crystallin molecules was markedly decreased in the nucleus, probably the result of precipitation with age into insoluble protein (Francois and Rabaey, '57

ISSN:0003-276X    

DOI:10.1002/ar.1091510211

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

年代:1965

数据来源: WILEY