摘要:

AbstractThe head of a young calf with diprosopus (two faces) and related cephalic malformations was dissected and grossly studied. The head was removed, preserved with 10% formalin, and the cephalic vessels were doubly injected with latex.The related outstanding cephalic abnormalities were: four eyes (tetrophthalmus) with the two adjacent eyes and orbits fused into a single median one; a large domeshaped head, characteristic of hydrocephalus; two mouths, each with a tongue, both of which protruded and retracted simultaneously; two cleft palates; duplication of the brain from the rostral end caudally to the mesencephalo‐metencephalic junction with each side of the brain containing a pituitary gland, paired cerebral peduncles, and an aberrant circulus arteriosus (circle of Willis). There were four olfactory bulbs and optic nerves, but only three oculomotor and abducens nerves. The aberrant median third and sixth cranial nerves were interpreted to be a fusion of the two adjacent nerves if duplication had been complete.Diprosopus is classified as a form of anterior twinning. The anterior brain duplication probably is referable to a doubling of the cephalic end of the neural tube followed by a diverging migration of the two frontal poles so that these areas finally are located at opposite lateral sides of the skull. The degree of neural tube duplication determines the extent of brain duplicatio

ISSN:0003-276X    

DOI:10.1002/ar.1091600202

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

年代:1968

数据来源: WILEY

摘要:

AbstractTylotrich follicles are present in the skin of the marsupial, the American opossum (Didelphis virginiana). Their morphology, ancillary structures, time of development, size and distribution of epidermal pads, are similar to tylotrich follicles found in eutherian mammals. The presence of tylotrich follicles in the marsupial suggests that they arose early in the evolution of mammalian skin.

ISSN:0003-276X    

DOI:10.1002/ar.1091600203

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

年代:1968

数据来源: WILEY

摘要:

AbstractTwin baboon embryos were acquired by hysterotomy from a multipara on the twenty‐sixth day of gestation. All preceding and succeeding pregnancies yielded single births. This case of dichorionic, diamniotic twins is unique because there is a seven day difference in the morphological development of the two embryos. The embryos are approximately the same fertilization age because mating was limited to one 12 hour period of the menstrual cycle. In addition only one corpus luteum was identified at laparotomy. Both twins were males as indicated by the sex chromatin, eliminating the positive identification of dizygosity. Several alternatives for the twins' origin are cited. One possibility is that there was a division of the blastomeres at the two‐cell stage, or at some other stage before implantation, yielding monozygotic twins. Another possibility is that both ova arose from the same follicle, yielding dizygotic twins. The larger embryo is 2.0 mm in greatest length and has six pairs of somites, and is similar to ten other baboon embryos 25–26 days old. The smaller embryo is of the trilaminar disc stage and is comparable in developmental features to five other baboon embryos 18–19 days old. The morphological features of each placenta are comparable in development to the age of its respective

ISSN:0003-276X    

DOI:10.1002/ar.1091600204

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe chorio‐allantoic placenta of the rabbit is of the labyrinthine hemodichorial type where the outer trophoblastic layer next to the maternal blood space is syncytial and the inner is cellular. The syncytium has thick and thin areas. It is at the thick areas that the trophoblast from either side of the maternal blood tubule encloses a narrow intertubular cleft which has numerous interdigitating microvilli and desmosomes. Intravenously injected thorotrast (an electron dense particle) and maternal plasma readily enter the intertubular cleft. Along the intertubular cleft numerous caveolae, arrays of rough endoplasmic reticulum and mitochondria are present in the syncytium suggesting that the clefts are areas in which fluid and certain metabolites are absorbed. The agranular membranous whorls are found in the syncytial thick areas. They enclose central or eccentric masses of lipid droplets. Small whorls are found during early pregnancy; smaller and larger ones, however, are found from midpregnancy to term. The whorls progressively increase in size as pregnancy advances. Membranes of the whorl and the rough endoplasmic reticulum are interrelated and contiguou

ISSN:0003-276X    

DOI:10.1002/ar.1091600205

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

年代:1968

数据来源: WILEY

摘要:

AbstractDeveloping pancreases from rat embryos of the sixteenth day of pregnancy and adrenals from embryos of the nineteenth day were grown in organ culture for six days. The cultures were transferred to fresh media twice, after 48 hours and after 96 hours of incubation. Control cultures consisted of pancreas alone and of adrenal alone.The pancreatic islets which were too young to have granulated beta cells on the sixteenth day of pregnancy differentiated into islets with many granulated beta cells during the culture period of six days. The pattern of granulated beta cells and the estimated number of these cells in cultures with adrenals were variable (not consistently different from those in the control cultures without adrenals).The adrenals from embryos of the nineteenth day had two zones of the fetal cortex outer and inner. Cultures of adrenals survived. The adrenals, whether minced or unminced at the time of the explantation and whether cultured alone or with pancreases, underwent little if any additional differentiation during the culture period.

ISSN:0003-276X    

DOI:10.1002/ar.1091600206

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

年代:1968

数据来源: WILEY

摘要:

AbstractGrowth of four muscles was studied in four lines of homozygous dystrophic chickens selected for high or low fat content of pectoralis muscles, or for early or late onset of disability. The light (“white”) pectoralis, supracoracoideus and biceps brachii and the dark (“red”) adductor muscles were studied. Growth characteristics were compared to a randomly mated dystrophic line and to normal chickens. Significant differences in muscle size occurred between lines but all dystrophic lines underwent the same sequence of events: gross hypertrophy of the white muscles during the first few weeks of life, followed enventually by gross atrophy. The dark adductor muscles did not differ consistently from normal. Hypertrophy was accompanied by increased protein (or fat‐free dry matter) and water content. Atrophy was accompanied by increased fat content. Selected lines exhibited greater uniformity and greater extremes of hypertrophy or atrophy than occurred in the ra

ISSN:0003-276X    

DOI:10.1002/ar.1091600207

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

年代:1968

数据来源: WILEY

摘要:

AbstractRadioautography was used to compare thein vivoincorporation of glycerol‐H3and galactose‐H3in intestinal absorptive cells in relation to glyceride synthesis. Each labeled compound was injected, either singly or mixed with linoleic acid chyme, directly into ligated segments of rat upper jejunum. The segments were removed at 5 and 20 minutes and prepared for light and electron microscopic radioautography. Following glycerol‐H3and chyme injections, label is rapidly incorporated in the vicinity of newly formed fat droplets in the apical endoplasmic reticulum. Later, labeled droplets accumulate in dilated Golgi cisternae and intercellular spaces. Galactose label is initially found in the Golgi region and later in the apical cytoplasm. Glycerol labeling is considerably reduced in the cells when the fat is extracted prior to radioautography, or when glycerol alone is absorbed. Galactose labeling is not affected by these procedures. The results indicate a significant incorporation of glvcerol label into newly synthesized glycerides, as previously also shown for glucose label. Galactose label follows a different metabolic pathway not related to glyceride synt

ISSN:0003-276X    

DOI:10.1002/ar.1091600208

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

年代:1968

数据来源: WILEY

摘要:

AbstractNeuro‐insular complexes (neural elements in juxtaposition to islet cells of the pancreas) were studied in Holtzman albino rats.Pancreases were stained by either the aldehyde‐fuchsin‐ponceau (A‐F‐P) or the acetylcholinesterase (ACHE) technique. The A‐F‐P stain gave good definition of islet structure. Although some nerve cell bodies were distinguishable with this stain, the AChE technique gave better definition of nerve cells, including interstitial cells of Cajal.In adult rats every islet examined had a nerve network. In newborns the nerve network was less apparent though some nerve elements were present. A nerve network typical of the adult was found in rats 48 hours after birth.Following insulin and glucose loading, variation in the localization of AChE was noted. It is suggested that neuro‐insular complexes have a modulatory influence on rele

ISSN:0003-276X    

DOI:10.1002/ar.1091600209

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

年代:1968

数据来源: WILEY

摘要:

AbstractIn the arcuate nucleus of the normal rat there are two types of neurons. One of them is characterized by a dense cytoplasmic matrix, dilated endoplasmic reticulum cisternae and well developed Golgi complexes; the other cell type by a paler overall appearance. In both of them granulated vesicles of about 1000 Å in diameter with a core of variable density are present. The frequent association between these vesicles and the Golgi complex suggests that they are formed in relation to this organoid. The presence of lysosomes and multivesicular bodies and their close relationship with granulated vesicles is analyzed.The neuropil of the nucleus is constituted by axons, dendrites and glial processes. The majority of the axon profiles and nerve endings contain a mixed population of clear and granulated vesicles, the latter having a diameter ranging between 600 to 1300 Å.The finding of granulated vesicles in arcuate neurons is discussed in relation with the known monoamine content of them and the dopaminergic nature of the fibers that form the tuberoinfundibular tract. It is suggested that these granulated vesicles contain primary monoamine

ISSN:0003-276X    

DOI:10.1002/ar.1091600210

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

年代:1968

数据来源: WILEY

摘要:

AbstractAs part of studies on Ehrlich's ascites tumor cells transplanted into Swiss mice some unique myeloid figures, were found with electron microscopy in parathyroid cells, consisting of electron dense rings partially or completely encircling the nuclei of many cells in 7 of the 30 treated animals examined. These dense rings were seen to be made up of tightly matted bands, which at free ends, spread out to become continuous with agranular endoplasmic reticulum. The nuclei of these altered cells were quite pleomorphic and were closer together than in normal tissue, indicating decreased cell volume. Rough endoplasmic reticulum was scarce, mitochondria were long and slender and free ribosomes were widely scattered in the cytoplasm. A possible explanation for the development of these focal areas of degeneration is given.

ISSN:0003-276X    

DOI:10.1002/ar.1091600211

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

年代:1968

数据来源: WILEY