摘要:

AbstractMultiply ciliated follicular cells have been observed in developing thyroid glands in dogs. These cells are prominent three weeks prior to the expected date of birth but become progressively less common as development proceeds. After birth only rare isolated cilia remain. No evidence of removal of cilia by autophagy or loss into colloid was found. It is concluded that cilia are probably no longer formed by mature cells and that those already present are diluted out by progressive division of mature follicular cells.

ISSN:0003-276X    

DOI:10.1002/ar.1091840202

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

年代:1976

数据来源: WILEY

摘要:

AbstractIn relation to chronological age and skeletal maturation, the growth of the second metacarpal is discussed based on radiographs of the right hand and wrist in 499 male and 424 female Japanese aged 1 to 18 years. When plotted against age, bone length and width present the general growth pattern of Scammon, the adolescent spurt occurring at about 13 years in the males and 11 years in the females, and the mean values are significantly larger in the males than in the females at age 15 years for length, and age 13 years for width, and later. The growth curves of both sexes are almost parallel to each other for bone length plotted against skeletal maturation. Bone width progresses in parallel in males and females until about adolescence, whereafter there is a more rapid increase in growth in the males than in the females. The mean values for length and width are almost always significantly greater in the males than in the females. The width/length index decreases rapidly until a certain period, the minimum value being at about ten years or a maturity corresponding to that age, and then increase slightly again to reach an equilibrium state on the basis of both age and skeletal maturation. At any given age, the mean values are always greater in the males than in the females. However, according to skeletal maturation, the sex differences are steadily significant at and after the skeletal maturity corresponding to about 12 years in the males and 10 years in the females.

ISSN:0003-276X    

DOI:10.1002/ar.1091840203

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe surface coat of syncytial trophoblast from term human placentas was studied using cytochemical methods (colloidal iron, alcian bluelanthanum nitrate, dialyzed iron) in coordination with tissue enzyme digestions (trypsin, neuraminidase) and sialic acid analyses. The presence of at least two highly acidic anionic components that contribute significantly to the surface negativity of trophoblast has been demonstrated. The first of these, sialic acid, was removed with neuraminidase. Tissue digestion with this glycosidase was accompanied by a decrease in trophoblast surface staining with colloidal iron, a decrease in tissue sialic acid, and an increase in the concentration of sialic acid in the incubating medium. Results from methylation experiments were consistent with the presence of sialic acid. The second anionic component(s) was identified by removal with trypsin of a glycocalyx constituent that stained with both colloidal iron and lanthanum. After trypsinization, tissue sialic acid levels were not significantly different from control values, and no detectable sialic acid was present in the incubating medium. The identity of this anionic component has not been established. Both sialic acid and nonsialic acid acidic components are distributed in higher density on membrane of microvilli than on intermicrovillous surface membrane. In addition, the sialic acid moieties appear to be clustered in the glycocalyx.

ISSN:0003-276X    

DOI:10.1002/ar.1091840204

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

年代:1976

数据来源: WILEY

摘要:

AbstractFemale rats were divided into six groups: (1) control, (2) one uterine artery (a.) ligated near the utero‐tubal (U‐T) junction, (3) one uterine a. ligated at the level of the cervix, (4) both uterine aa. ligated separately at the U‐T junction, (5) both uterine aa. ligated separately at the cervix and (6) both uterine aa. tied with one ligature at the cervix. Segmental aa. were disrupted in all experimental groups except group 6. Animals were allowed to recover for ten days and killed the first metestrus thereafter. Number of eggs ovulated was determined by flushing the oviduct with saline solution and counting the ova.Control rats ovulated 5.0 ± 0.4 eggs per ovary. Groups 2 and 3 had an increase in the number of eggs shed from the ovary on the non‐ligated side. In contrast, a decrease in the number of ova shed occurred on the ligated side. When both aa. were ligated separately (groups 4 and 5), irrespective of location, a decrease in the number of eggs shed by both ovaries was evident. No effect was found when only one ligature was placed near the cervix (group 6).The data demonstrate that blood supply to the ovary via the uterine artery is essential for the full complement of eggs to

ISSN:0003-276X    

DOI:10.1002/ar.1091840205

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe macroscopic anatomy of the brain of the American Plains Buffalo (Bison bison bison) is detailed herein for the first time. Many features vary significantly from most previously described ungulate species including its large size, fissural pattern of the cerebral hemispheres and well developed insular cortex. The midbrain, particularly the tectum, is outstanding: the superior colliculi appear to be the largest reported for any mammal and occupy most of the dorsal midbrain by surface area and volume estimates. The cerebellum is small relative to the total brain volume, a peculiarity reported elsewhere for other ungulates. Morphometric criteria further indicate the brain of bison is highly specialized. Drawing from various lines of evidence, it is suggested that the anatomical uniqueness of the present day bison brain may represent a vestige of the past, remaining largely unchanged over a broad expanse of geologic time.

ISSN:0003-276X    

DOI:10.1002/ar.1091840206

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

年代:1976

数据来源: WILEY

摘要:

AbstractRat testes fixed by vascular perfusion were examined by scanning and transmission electron microscopy. This revealed a complex organization of the interstitial tissue and an extensive “testicular lymphatic space” composed of continuous “peritubular lymphatic sinusoids.” No cellular connections exist between the interstitium and the tubules. Each sinusoid completely surrounds an individual seminiferous tubule, and adjacent sinusoids communicate freely through fenestrae in the interstitium. Thus, material must enter the lymph to gain access to the tubules. The sinusoids are delimited by separate endothelial cell layers over the tubules and interstitium. The layer over the interstitium is discontinuous in specific areas according to the geometry of the tubule packing. Interstitial tissue located in the flattened biconcave interstices between two adjacent tubules is consistently covered with endothelial cells, while that located in the open, triangular interstices between three or more tubules consistently lacks an endothelium. Most of the Leydig cells are located in the “open interstitium” and are directly exposed to the lymph. Physiological implications of the “testicular lymphatic space” and additional features of the interstitiu

ISSN:0003-276X    

DOI:10.1002/ar.1091840207

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

年代:1976

数据来源: WILEY

摘要:

AbstractExplanted blastoderms of freshly laid chicken eggs expand their area during the first 44–45 hours of incubation by a factor of at least 11 if they are placed with the epiblast on the inner surface of explanted fresh chick vitelline membrane and provided with chick egg extract. This expansion is due essentially to the spreading of the yolk sac‐serosal membrane. On turkey and duck membrane the expansion factor is about 6 and 3.8 respectively under otherwise identical conditions, but 1.9 only on a semisolid nutrient agar plate. Only the inner surface of the vitelline membrane has this growth‐promoting potential, which markedly and progressively declines during incubation in ovo because of systemic factors rather than because of a direct influence by the outgrowing yolk sac‐serosal membrane. Trypsinization of fresh chick vitelline membrane (1% trypsin 3 hours) reduces the growth‐promoting potential to about 40% of its normal strength. The outgrowth of the extraembryonic tissues on vitelline membrane is better supported in the presence of a species' own egg extract than by extract from anothe

ISSN:0003-276X    

DOI:10.1002/ar.1091840208

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects of colchicine and vinblastine on tanycytes of the rat median eminence have been studied using the electron microscope. Colchicine and vinblastine were administered by intraventricular cannulation into the third ventricle and demonstrated distinct morphological effects on tanycyte microtubules. Highest drug doses administered were 50.0 μg in 5.0 μl of saline initially, followed by an additional 50.0 μg of these agents infused in a volume of 13.0 μl saline over an hour. Colchicine treatment resulted in the formation of large crystalloids within tanycytes, coincident with the disappearance of microtubules, all along the ventricular surface. Nonetheless the tanycytes appeared able to maintain a continuous tight lining, as in controls, although some crystalloids were observed beneath the ventricular surface, either within tanycyte processes or within neuronal processes. Vinblastine treatment also resulted in the formation of identical crystalloids but at highest doses thoroughly destroyed the tanycyte lining of the median eminence and exposed cellular elements below the surface to the drug. Portal capillaries approaching the ventricular surface were generally free of any signs of drug response to either colchicine or vinblast

ISSN:0003-276X    

DOI:10.1002/ar.1091840209

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

年代:1976

数据来源: WILEY

摘要:

AbstractPieces of rat and human gastric mucosa were fixed in glutaraldehyde and paraformaldehyde and were processed by the methods of Wach‐stein‐Meisel and of Ernst for the cytochemical demonstration of adenosine triphosphatase (ATPase) and p‐nitrophenylphosphatase (NPPase) respectively. Electron microscopic examination of reacted sections revealed the ATPase reaction to be localized to the plasmalemma and to mitochondrial cristae and the NPPase reaction to the plasmalemma. The tubulovesicles were unreactive. By thus demonstrating a cytochemical difference between the plasmalemma and tubulovesicle membrane, this study suggests that the tubulovesicles do not represent an extension of or reserve ofmatureplasmalemma. If the tubulovesicles represent a reserve of membrane that can be rapidly utilized to expand the plasmalemma, then these studies suggest that additional membrane constituents are added, activated, or unmasked in the pr

ISSN:0003-276X    

DOI:10.1002/ar.1091840210

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

年代:1976

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091840201

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

年代:1976

数据来源: WILEY