ISSN:0002-9106    

DOI:10.1002/aja.1001320102

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

年代:1971

数据来源: WILEY

摘要:

AbstractA study was made of the concentration and cellular localization of serotonin in the thyroid gland of the dog. This species is characterized by a low level of serotonin in the adult thyroid gland. Endogenous serotonin consequently cannot be demonstrated by fluorescence microscopy following treatment of frozen‐dried adult thyroid tissue with formaldehyde vapor. In contrast, the thyroid concentration of serotonin was found to be high, in both beagle and basenji (purebred dogs of European or African origin respectively), around the time of birth. The serotonin concentration then fell rapidly as development of the animals proceeded. This pattern also seemed true of the rabbit. When the concentration of serotonin was high, just prior to birth, a yellow fluorophore, probably the condensation product formed between serotonin and formaldehyde could, as in other species, be demonstrated in parafollicular cells after exposure of tissue to formaldehyde gas. Thyroid follicular cells never showed serotonin but instead, a striking accumulation of autofluorescent apical dense bodies (0.3–1.0 μ in diameter), probably lysosomes, occurred during the first year of

ISSN:0002-9106    

DOI:10.1002/aja.1001320103

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe motoneuron columns of the obturator and pectineal nerves were localized within the lumbar spinal cords of dogs by observing retrograde chromatolysis following resection of the respective nerves. The obturator column was located in segments L4 through L6 while the pectineal column was located in segments L4 and L5. The dorsal‐to‐ventral and medial‐to‐lateral boundaries were determined for each column and the pectineal column was located within the boundaries determined for the obturator column in segments L4 and L5. Antidromic stimulation of the pectineal nerve localized the origin of motor fibers from lumbar spinal nerves L4 and L5. The results provide an anatomical basis for studies of motoneurons innervating the pectineus muscles of dogs affected with a developmental myopathy of this

ISSN:0002-9106    

DOI:10.1002/aja.1001320104

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe anterior abdominal fat body is a mixture of multilocular and unilocular fat cells. It is found deep to the rectus sheath and immediately beneath the peritoneum of the anterior abdominal wall. It is first seen in the sixth month fetus as thin lobules of tissue arranged on either side of the umbilical vein but receiving blood supply from specific ensiform branches of the superior epigastric or internal thoracic artery and vein. Continued growth results in a coalescence of the bilateral lobules into a single fat body that completely overgrows the supportive blood vessels. In its cytology this body is comparable to the interscapular fat pad. It is unique in that vascular connections develop between it and the liver and in the fact that in a significant number of specimens it attains proportions that appear to represent pathological hypertrophy.

ISSN:0002-9106    

DOI:10.1002/aja.1001320105

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

年代:1971

数据来源: WILEY

摘要:

AbstractTransport and capacitation of spermatozoa, and the normality of the process of fertilization, were examined after unilateral resection of the isthmus and end‐to‐end anastomosis of the remaining portions of the Fallopian tube. The operation was performed in eighteen rabbits, in each of which the contralateral tube remained intact to serve as a control.Recent ovulations were present in fourteen animals at autopsy, although in only eleven were ovulations detectable on the side of the anastomosis. Thirteen animals yielded a total of 89 eggs, the proportion recovered from the control tube (79.3%) being significantly higher than that from the anastomosed tube (57.2%). Six of nine anastomosed tubes yielding eggs were patent to sperm passage, and 67% of the eggs recovered from this side were fertilized compared with 91% from the control tubes. Three eggs recovered from the anastomosed tube of three animals were dispermic. It is concluded that normal fertilization and early cleavage of rabbit eggs can take place in the absence of the isthmus, and that the rate of cleavage is not retarded under such conditions. An increased number of spermatozoa on the eggs from the anastomosed tube, together with the incidence of dispermic eggs, indicates that the isthmus exerts considerable control over sperm transport to the site of fertilizat

ISSN:0002-9106    

DOI:10.1002/aja.1001320106

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

年代:1971

数据来源: WILEY

摘要:

AbstractA thiocholine technique was used to visualize nerves in human and rat umbilical cords. The allantoic part of the rat umbilical cord was found to be separate from the vitelline part of the cord and its vessels were not innervated. However, acetylcholinesterase‐positive nerves formed a plexus around the vessels of the vitelline part of the 21‐day rat umbilical cord. These nerves displayed fusiform swellings and terminated as simple endings close to the yolk sac wall. The findings suggest that the vitelline circulation in the rat may function under neural control.An investigation of full‐term human umbilical cords revealed extrafetal acetylcholinesterase‐positive nerves. Nerve bundles passed from the fetus into the cord and split into a plexus. Beaded nerve terminals were found about 15–20 cm from the fetus. Some of these endings touched the media of the vein; others ended freely in the cord substance between the arteries and the vein. There were no periarterial terminals and no nerves were found in the maternal half of the cord.The free nerve endings in the human cord may have been sensory, since they made no terminal effector contact. However, it should be noted that similar terminals touched the media of the umbilical vein. The endings described could be sensory receptors for the sphincter of the ductus venosus that controls venous return from

ISSN:0002-9106    

DOI:10.1002/aja.1001320107

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe appearance and the osmiophilic properties of synthetic dipalmitoyl lecithin (DPL) were characterized under various conditions. It was shown that DPL appeared as 50 Å round to oval dots and lamellae of 50 Å periodicity when negatively stained with phosphotungstate. Osmium‐vapor treatment of a DPL suspension produced negatively outlined DPL, similar to the images obtained with negative staining with phosphotungstate. A mixture of ethanol, osmium and DPL showed the heavily osmiophilic lamellae of DPL in thin sections. The periodicity measures 42 Å. These results are the first in the literature to reveal the osmiophilic nature of saturated dipalmitoyl lecithin.Prolonged washing after both glutaraldehyde and osmium fixation of lung tissue, thus eliminating the chance for interaction among osmium tetroxide, ethanol and saturated phospholipid, resulted in a loss of the heavily osmiophilic surface film that has been reported to be present after routine tissue processing. Secondary osmication of the washed lung with a mixture of osmium tetroxide and ethanol solution brought about striking osmiophilia of the surface film, which was lamellar and was identical to synthetic DPL in its periodicity.It is suggested that the osmiophilic line observed after routine tissue processing is saturated phospholipid that binds osmium during the process of ethanol dehydration immediately following osmium fixa

ISSN:0002-9106    

DOI:10.1002/aja.1001320108

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe effect of systemic administration of a typhoid vaccine (T.A.B.) on the marginal zone of rat spleen has been investigated by light and electron microscopy. This bacterial preparation damages granulocytes in the circulating and marginated pools and the damaged cells are sequestered in the spleen, particularly in the marginal zone. The activities of the vaccine are attributed to its endotoxic properties. Terminations of arterial vessels in the marginal zone are also described.

ISSN:0002-9106    

DOI:10.1002/aja.1001320109

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

年代:1971

数据来源: WILEY

摘要:

AbstractAutoradiographic determination of the number and distribution of replicating cells in the colonic muscularis externa of adult rabbits was carried out, using animals sacrificed between 11 minutes and 14 days after a single‐dose‐pulse of3H‐thymidine; or using animals sacrificed between two hours and 21 days after a multiple‐dose‐pulse of3H‐thymidine. Labeling of smooth muscle cells was seen as early as 11 minutes after injection. By two hours after a multiple‐dose‐pulse more than 0.3% of the cells of the colonic muscularis externa were heavily labeled. Both the number of labeled cells and the number of labeled pairs, triplets and nests of cells increased with time after injection of3H‐thymidine. There was a very regular reduction in grain count per nucleus during the 21 day period. No regular migration away from the site of division was observed.This tissue, like the tunica media of blood vessels and the panniculus adiposus, exhibitsindependent replication and no migration. The colonic muscularis externa can be classified as aslowlyre

ISSN:0002-9106    

DOI:10.1002/aja.1001320110

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe level of protein synthesis by hamster embryosin vivo, as inferred from the incorporation of35S methionine, was determined for the four days of the preimplantation period by radioautography. The embryos incorporated35S methionine throughout the preimplantation period. Furthermore, the hamster eggs continued to incorporate35S methionine following ovariectomy. Therefore, the pattern of protein synthesis in hamster eggs differs from the mouse with its low levels in cleaving eggs and in blastocysts following ovariectomy and high levels in blastocysts influenced by estrogen and progesterone.This finding is of interest because unimplanted mouse embryos remain viable in ovariectomized females for many days, whereas hamster embryos rapidly degenerate. It is suggested that the inability of hamster eggs to reduce the level of protein synthesis and become “dormant” may prevent their survival if implantation is blocked by ovariect

ISSN:0002-9106    

DOI:10.1002/aja.1001320111

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

年代:1971

数据来源: WILEY