摘要:

Summary1. The following significant facts have been pointed out:(a) The yolk sac of Osteichthyes (bony fishes) and Amphibia is supplied by blood from body veins, while that of Selachii (cartilaginous fishes) and Amniota receives blood by way of direct branches from the dorsal aorta.(b) The allantois is always supplied directly from the aorta by the umbilical arteries. Its venous drainage is at first by way of the umbilical veins directly to the heart, but later part or all of it passes through the liver sinuses.(c) A hepatic portal system exists in all Vertebrata, but in developing Amniota a by‐pass around the liver sinuses is provided in Aves and Reptilia by the meatus venosus, and is often provided in Mammalia also by the ductus venosus. These structures allow the allantoic vein blood and some of the vitelline and intestinal vein blood to reach the heart directly. Anterior abdominal wall and urinary bladder blood and some from the caudal region and posterior extremity drain into the hepatic portal and liver sinuses in Amphibia and Reptilia, and to a slight extent in birds and monotremes through the anterior abdominal vein or its homologue.(d) A renal portal circulation is present in all Vertebrata during embryonic life. It is present in the adults of all except Mammalia. It is apparently modified by the presence of venous anastomoses between afferent and efferent renal veins in many of these. Its anatomical and physiological relation to the renal tubules has been denied by at least one recent investigator.(e) The gills always receive blood directly from the heart by way of the ventral aorta and are drained by efferent arteries leading directly to the roots of the dorsal aorta. Head arteries arise from some of the efferent branchials, and in certain fishes pulmonary arteries also arise from them. Typical tetrapod lungs receive their functional supply by arteries directly from the heart or ventral aorta, and drain by veins directly into the heart. On the other hand, the lungs of lung‐fishes and the swim‐bladder of other fishes receive blood either from the dorsal aorta or from branches of the efferent branchial arteries and drain into both the systemic venous system (sometimes in part via the renal portal) and the hepatic portal in most fishes, and more or less directly to the heart inAmia, Cladista and Dipneusti.2. The following possibilities and problems have been discussed:(a) The blood supply of the yolk sac of Osteichthyes and Amphibia is fundamentally different from that of Selachii and other vertebrates, indicating a difference in the physiology of the yolk sac and in its evolutionary development in these two groups. In this respect, then, selachian ontogeny is much closer to that of the amniotes than to that of other anamniotes.(b) The logic in the by‐passing of the liver by allantoic blood in those forms where the allantois is primarily respiratory is pointed out, as well as the possible carbohydrate regulating function of the liver in those foetuses (mammals) where the allantois has a nutritive function. Explanation for the complete absence of a ductus venosus in some mammals is lacking.(c) A hepatic portal system is a characteristic of all vertebrates, so far as the conveying of blood to the liver from the absorptive part of the gut is concerned. It is pointed out, however, that in certain groups large amounts of blood from the body wall and caudal half of the body also pass through the liver. The best explanation for this may be that it is an accident of development, for there does not seem to be any obvious function served by this condition. The importance of the drainage of non‐absorptive portions of the alimentary tract and other organs through the liver for specific physiological purposes is considered.(d) Despite the universal occurrence of a renal portal system in either the adults or developmental stages of all vertebrates, its physiologic importance is still an unsettled question. Phylogenetically it is certainly one of the fundamental characteristics of vertebrates.(e) The reason for the position of the gills in the arterial circuit from the heart to the rest of the body is obvious. The retention of the “cstigial branchial apparatus, including the vessels, in higher vertebrates is one of the best examples of persistence of ancestral structures, not for their primitive physiological function during a transitory period, but because they are the building blocks from which greatly modified specialized parts of the higher forms are constructed.(f) The position of tetrapod lungs in the circulatory sequence, receiving as they do non‐aerated blood, is contrasted to that of the swim‐bladder and lung‐fish type of lung which receive at least partially aerated blood which has already passed through the gills. This is in line with the ‘storage tank’ function of the latter type of lung and the swim‐bladder, as compared to the aerating fu

ISSN:1464-7931    

DOI:10.1111/j.1469-185X.1948.tb00560.x

出版商:Blackwell Publishing Ltd    

年代:1948

数据来源: WILEY

摘要:

Summary1. The usual criteria for identification of glycogen are discussed. It is pointed out that these can be applied equally well to amylopectin and α‐amylodextrin. Numerous so‐called glycogens in plants and micro‐organisms may not be chemically identical with animal glycogens, which may quite well vary among themselves.2. Mention is made of the methods of isolation and purification. It is considered that precipitation by acetic acid gives the purest material in that nitrogen and phosphate can be eliminated, in many cases entirely.3. The limitations of the end‐group assay are discussed. This method reveals the sole fact that all glycogens are built up from ‘unit chains’, but gives no information as to the detailed structure of these chains. It is, therefore, not possible to say whether glycogens from different sources are chemically the same or not.4. A description is given of the difficulties in attempting to analyse glycogens from the aspect of determining the nature of the linkage uniting the unit chains. The suggestion is made that information to this end will have to be obtained by use of stepwise enzymic degradation of the polysaccharide.5. The latest work on molecular weights is summarized. There is considerable variation according to the type of source from which the glycogen has been isolated. This work is the first indication that there are at least physical differences betwe

ISSN:1464-7931    

DOI:10.1111/j.1469-185X.1948.tb00561.x

出版商:Blackwell Publishing Ltd    

年代:1948

数据来源: WILEY

摘要:

RésuméAprès avoir rappelé brièvement la signification et ľimportance des cellules réticuloendothéliales ou histiocytaires, qui sont très répandues et qui, grâce à leurs potentialités multiples, jouent un role considérable dans ľorganisme, à la fois dans les conditions normales et pathologiques, le présent travail résume et situe les principales connaissances qui ont été acquises récemment dans le domaine de la biologie de ces cellules.Tout ďabord, plusieurscaractères cytologiques et propriétés biologiques des histiocytes et macrophagesont pu être précisés ou établis (étude de leur structure et de leurs fonctions en relation avec ľorigine et la localisation; histochimie de leurs lipides; athrocytose et phagocytose; absorption et stockage de vitamines, etc.).Un nouveau type ďhistiocyte a été individualise et décrit: leshistiocytes graisseux, ďoù dérivent les cellules adipeuses de la graisse de formation secondaire.Les cellules histiocytaires présentent aussi la propriété importante de pouvoir se formerde novo, à partir de cellules ďun tout autre type; c'est latransformation histiocytaire. Celle‐ci se produitin vitro, aux dépens de lymphocytes, de cellules du type fibrocytaire des souches de cæur ou de tissu conjonctif, de mésenchyme, ďentoblaste vitellin, de fibrocytes du tissu sous‐cutanéà différents âges, ďéléments des muscles squelettiques ou lisses, de cellules de Schwann. Cette transformation spontanée est particulièrement fréquente dans les cultures non repiquées de muscles squelettiques ou de conjonctif.On peutprovoquer expérimentalementla transformation histiocytairein vitropar des moyens variés et avec des résultats divers. Des substances chimiques pures se sont révélées actives; ce sont ľarsenic (sur les fibrocytes de souches), le sulfate ďatropine (sur les cultures de cceur ou de mésenchyme) et surtout des ammoniums quaternaires du groupe de la choline (sur des cultures ďentoblaste vitellin de la vésicule ombilicale) et la choline et ľacétylcholine (sur des cultures non repiquées de muscles squelettiques ou de conjonctif sous‐cutané).Ľimportant problème dudéterminisme de la transformation histiocytaire spontanéea étéétudié. Dans le cas des cultures de tissu conjonctif sous‐cutané et dans celui des cultures de muscles squelettiques, c'est lacholinequi est le facteur déterminant de la transformationin vitrodes éléments conjonctifs ou musculaires en macrophages.Des‘facteurs cellulaires’, encore peu connus, jouent un rô1e dans ces processus; ľétat de la cellule appelée à se transformer intervient.La transformation histiocytaire peut aussi se produirein vivoau cours de divers phénomènes (nombreuses réactions inrlammatoires localisées ou généralisées; dégénérescence et reagénération des muscles; certaines tumeurs musculaires, etc.). II est possible que ce soit également la choline qui interviennein vivo. Plusieurs arguments en faveur de cette thèse sont cités, mais les recherches doivent être poursuivies pour tenter de déceler les substances éventuellement en cause dans divers cas.De la choline peut apparaître et se former secondairement au niveau des tissus, dans différentes circonstances,in vivoetin vitro.Ľaspect decellules épithélioïdes et de cellules géantesque prennent dans certains cas des cellules histiocytaires, est probablement déterminé par des substances chimiques, peut‐être avec ľinfluence favorisante de la sous‐oxygénation locale. Dans la tuberculose, il semble bien que leur formation soit due à des substances protéidiques insolubles provenant des bacilles de Koch.La notion nouvelle deľétat histiocytaireest exposée. C'est ľétat cellulaire particulier que beaucoup de cellules différenciées et de types divers prennent en se changeant en histiocytes et macrophages. II est caractérisé surtout par son aspect fonctionnel.Parce que, pour différentes raisons, il est erroné et prête à confusion, le terme ‘réticuloendothélial’ doit être abandoné. I

ISSN:1464-7931    

DOI:10.1111/j.1469-185X.1948.tb00562.x

出版商:Blackwell Publishing Ltd    

年代:1948

数据来源: WILEY

摘要:

Summary1. Published descriptions of the development of the corpus luteum show that the majority of the luteal cells are derived from the granulosa cells.2. In the vertebrates, other than mammals, the development of a corpus luteum does not appear to be associated solely with viviparity.3. The fate of the theca interna cells varies greatly, even in closely related species.4. The theca interna cells may remain in groups at the periphery of the gland, or they may invade the developing corpus luteum and either: (a) disappear entirely a few days after ovulation, (b) become indistinguishable from the granulosa cells, or (c) possibly revert to fibroblasts.5. The function of the theca interna or theca‐luteal cells in the mature corpus luteum is unknown. It is, however, possible that they secrete oestrogen.6. The blood vessels of the corpus luteum are derived from the theca interna plexus of capillaries; the corpus luteum is well vascularized by the time that implantation occurs.7. The connective tissue of the corpus luteum is believed by many authors to be derived from theca interna cells that have reverted to fibroblasts. In the Artiodactyla and inMacaca, and possibly in other animals, there is evidence that the endothelial cells give rise to the reticular framework.8. The corpus luteum is generally fully developed by the time of implantation of the blastocyst.9. The appearance of the vacuoles in the luteal cells of pregnant mammals is not necessarily indicative of impending cessation of function or of degeneration. Such vacuolation may mark a ‘resting period’ as in those animals in which implantation is delayed, or a ‘transition period’ during which the placenta is becoming established structurally and functionally.10. The time of appearance of retrogressive changes in the corpus luteum of pregnancy in any species is probably related to the degree of activity of the placenta in that species and to the prolactin level in the anterior pituitary.11. Accessory, aberrant and other atypical forms of corpora lutea have been reported in the macaque, the tree porcupine and

ISSN:1464-7931    

DOI:10.1111/j.1469-185X.1948.tb00563.x

出版商:Blackwell Publishing Ltd    

年代:1948

数据来源: WILEY