摘要:

AbstractIn over 50 cases the pubo‐ischio‐tibialis muscle in mature axolotls was removed, minced and the minced fragments replaced into the site from which the muscle was removed. In 13 control animals the same muscle was removed but nothing was replaced. Regenerates were studied at post‐operational intervals of up to 150 days. Both grossly and histologically the regeneration of muscles from minced fragments in the axolotl follows a course very similar to that observed in frogs and rats. There is an initial period of destruction of the sarcoplasm of the minced muscle fragments. This is characterized by intense phagocytic activity. Following this, a population of myoblasts is established and the differentiation of mature muscle fibers ensues. The regeneration of muscles from minced fragments is compared with the formation of muscles in regenerating limbs. Following mincing, new muscle fibers develop rapidly and without the mediation of a blastema. Following limb amputation, a blastema is established before any differentiation of muscle occurs in the regenerate. This occurs more slowly than the differentiation of muscle fibers following mincing. The implications of these differences are disc

ISSN:0003-276X    

DOI:10.1002/ar.1091660302

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

年代:1970

数据来源: WILEY

摘要:

AbstractWeanling male and female littermate Osborne Mendel rats were randomly separated into two groups. The control group was fed a grain ration. The second group was fed a high fat ration which ultimately produced obesity. Male and female rats were killed at weaning (body weight, 50–60 gm). Thereafter rats from both diet groups were killed after an initial weight gain of about 100 gm and subsequent gains of about 150 gm. The inguinal, forelimb (axillary), interscapular perirenal, genital, xiphoid, and mesenteric and omental fat depots were removed, weighed, and weights recorded. Fat depots usually increased in weight more rapidly than overall body weight. This was typical of younger rats from both diet groups, but more pronounced in rats fed the high fat ration. The perirenal depots increased in weight more rapidly than body weight throughout the 450+ days of the study. In both sexes and diet groups, from weaning through sexual maturity, the weight of the genital fat depots increased proportionately more rapidly than body weight. Thereafter, the weight gain more nearly paralleled the body weight gain. In both diet groups, with the exception of the interscapular depot, the subcutaneous depots increased rapidly in weight during the first 100 days of life. The weight gain of these depots maintained a close relationship to body weight gain after 100 days of age. The interscapular depot in obese females increased at a very rapid rate as the animals approached 900 gm of body weigh

ISSN:0003-276X    

DOI:10.1002/ar.1091660303

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

年代:1970

数据来源: WILEY

摘要:

AbstractWeanling male mice of strain C57B1. were fed a lard‐enriched diet for periods of 1, 4, 7, 10, 14, or 28 days. Beginning during the second week of consumption of this ration, articular chondrocytes of the femoral heads were increased in number and size and showed ultrastructural changes. The latter manifested themselves in nuclear enlargement, intensification of organellar development and in acceleration of regression. There was no evidence of abnormal deposition of lipid material within the chondrocytes beyond that due to organellar disintegration. It was concluded that the early effects of a lard‐enriched diet on articular cartilage consist of an overall stimulation of cell function followed by premature exhaustion. The primary site of action of the dietary fat remains unkn

ISSN:0003-276X    

DOI:10.1002/ar.1091660304

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

年代:1970

数据来源: WILEY

摘要:

AbstractTwelve nulliparous New Zealand White female rabbits, and eight nulliparous Hereford heifers were used for profile analysis of the oviductal layers afterin vivoandin vitrofixation of the oviducts. The unstraightened oviducts were cut into eight segments of about 1 cm starting from the uterotubal junction. Using a projection microscope, the areas of the lumen, mucosa + submucosa, and musculature of cross sections from each segment were measured planimetrically. The lumen of segments 5 and 6 (from the fimbriae) had the smallest surface area at all reproductive stages in both species. At about 72 and 168 hours after ovulation, the surface area of the lumen at these two segments increased by two‐fold compared to the estrous stage. The ampullary‐isthmic junction (AIJ) is probably located at 6/10 to 7/10 of the oviductal length (segment 5 or 6) in both species. The widening of the lumen at the AIJ, 60–70 hours post ovulation, is sufficient to allow the trapped eggs to pass rapidly to the uterus. The whole isthmus and particularly the AIJ seems to function as a sphincter, the closure of which may be coordinated by neuro‐endocrine mec

ISSN:0003-276X    

DOI:10.1002/ar.1091660305

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe ultrastructure of whorls of rough endoplasmic reticulum in the adrenal gland of the Mongolian gerbil (Meriones unguiculatus) was examined during and after treatment with ACTH. Whorls were loosely wound after treatment for one day and consisted of only a few paired membranes. Focal areas of increased tubular smooth endoplasmic reticulum were seen throughout the cytoplasm of the cells. Whorls disappeared altogether after three days of ACTH treatment. The structures reappeared one day after stopping the ACTH injections and seemed to enlarge progressively by addition of membranes to the periphery of the structures. Numerous vesicles and sometimes parallel cisternae of rough endoplasmic reticulum were observed in the cytoplasm of adrenocortical cells containing newly forming whorls. The whorls apparently serve as a readily available reserve of rough endoplasmic reticulum, which can transform into smooth reticulum upon stimulation with ACTH.

ISSN:0003-276X    

DOI:10.1002/ar.1091660306

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

年代:1970

数据来源: WILEY

摘要:

AbstractTwinning or duplication was observed in 28 eggs of the common snapping turtle,Chelydra serpentina serpentina.The methods of observation made detection of separate blastodiscs relatively certain, that of duplication within a blastodisc less so. Only two of the latter were found. Twins occurred in about 1% of the eggs; 26% of the clutches had one or more abnormal eggs. Twinned blastodiscs developed normally in early stages. When incubated through hatching, 12 out of 12 sets of twins developed unequally so that one was essentially normal, the other was small and not viable. In one case, in which the carapace of the smaller twin was three quarters the length of the larger, both died during hatching. The pigmentation patterns of the carapace of these twins differed; this indicates that they are fraternal rather than identical twins.

ISSN:0003-276X    

DOI:10.1002/ar.1091660307

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

年代:1970

数据来源: WILEY

摘要:

AbstractRecent morphological studies have revealed that the hominoid ulna has become progressively excluded from direct articulation with the carpus by the elaboration of an intervening intra‐articular meniscus, which in gibbons contains a bony lunula. In man this meniscus has merged with the triangular articular disk, forming a confluent proximal articular surface and constricting off a diverticulum of the synovial radiocarpal cavity, the prestyloid recess, which may lodge the ulnar styloid process. The present study reassesses the development of the human fetal joint in the light of these findings. Initially separate radioscaphoid, radiolunate and ulnotriquetral synovial cavities communicate to form a single continuous wrist joint cavity; the pisotriquetral cavity, at first independent, frequently establishes continuity with the wrist joint cavity, the normal condition in most Primates. After the 60 mm C. R. stage the ulna withdraws from the carpus and an intervening meniscus and prestyloid recess are elaborated. In a number of specimens a cartilaginous nodule, the so‐called intermedium antebrachii, has been observed adjacent to the ulnar styloid process. There is little doubt that this nodule, which may ossify, is homologous with the gibbon lun

ISSN:0003-276X    

DOI:10.1002/ar.1091660308

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe mandibular incisor of the 16 day embryonic mouse was divided into three visibly equal thirds; each third was explantedin vitroto test its capabilities for independent development. Ameloblasts and odontoblasts, present in the distal third at the time of isolation, fail to continue their differentiation. This third flattens, and the tissues become disorganized. Grouping several distal thirds in a single culture did not promote tissue differentiation. The embryonic proximal third remains cohesive The tissues differentiate; both ameloblasts and odontoblasts deposit extracellular matrix. Approximately half of the cultures of the intermediate third show differentiated odontoblasts and extracellular matrix after 11 culture days. Measurements of the volume changes of ameloblasts, odontoblasts, and general mesenchyme were taken over the first six culture days for each third of the rudiment. The volume changes recorded, and the counts of mitotic figures reflect the developmental behavior of each fraction of the rudiment.

ISSN:0003-276X    

DOI:10.1002/ar.1091660309

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

年代:1970

数据来源: WILEY

摘要:

AbstractUnlike other rat veins of comparable diameter, the smooth muscle cells of the extrahepatic segment of the portal vein are arranged in two distinct mutually perpendicular layers. The relatively narrow inner layer is nearly circumferential and devoid of vasa vasorum; the cells resemble those seen in other veins. In the longitudinal outer layer, vasa are abundant and the cells contain unusual numbers of mitochondria and abundant pinocytotic vesicles, indicating relatively increased metabolic activity. Between the layers, the connective tissue contains nerve fibers, suggesting coordinated reflex activity.

ISSN:0003-276X    

DOI:10.1002/ar.1091660310

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

年代:1970

数据来源: WILEY

摘要:

AbstractMorphologically the oviduct of the frog,Rana pipiens, consists of a lining epithelium and tubular jelly‐secreting glands. The oviduct can be divided into six regions (designated R1 anteriorly—R6 posteriorly) based on the differential staining of the jelly glands. The regions measured 1, 5, 6, 3, 20 and 3 cm, respectively. These regions correspond to 6 histochemically distinct layers of jelly (designated J1 nearest the egg through J6 farthest from the egg) which are deposited around the egg during the egg's sojourn in the oviduct. A correlation between lengths of each oviducal region and thickness of individual jelly layers was observed. That is, J5 is the thickest, followed by J3, 2, 6, 4 and J1 which is thinnest.Histochemical properties of jelly glands and corresponding jelly layers were essentially the same in the tests performed. All regions and layers except R5 and J5 contain a large amount of acid mucopolysaccharide and the mucopolysaccharide in R and J1, 3 and 4 is sulfated. Neutral mucopolysaccharide is present in R2, J2, R5 and J5. Although protein is present in all layers and oviducal regions it was found in higher concentration in R and J1, 3 and 6 and in lowest concentration in R and

ISSN:0003-276X    

DOI:10.1002/ar.1091660311

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

年代:1970

数据来源: WILEY