摘要:

AbstractEctopic glomeruli and proximal convoluted tubules were found in the kidneys of the rat, cat, dog, rabbit and ferret and in the human full‐term fetus. They lay in the connective tissue around the main intrarenal vessels and deep to the pelvic mucosa. Their afferent arterioles were long and gave branches to the pelvic mucosal plexus, while their efferents supplied the pelvic mucosa and the medulla, or one or the other of these tissues. In the rabbit the ectopic glomeruli often produced small cysts in the pelvic septum. Degenerating ectopic glomeruli were occasionally found and in the dog the majority of them showed this change. In the adult human kidney, aglomerular arteries supplied both the pelvic mucosa and the medulla and it is suggested that such arteries are the result of degeneration of ectopic glomerul

ISSN:0003-276X    

DOI:10.1002/ar.1091490102

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

年代:1964

数据来源: WILEY

摘要:

AbstractA method is described for making simple balloon cannulas. These may be inserted into the depths of the brain of the experimental animal and inflated, resulting in the production of a permanent destructive lesion characterized by hemorrhagic necrosis of the parenchyma, elements of the stroma being preserved peripherally. In time, a smooth, well‐defined membrane delineates the oval shaped cavity resulting in a sharply punched‐out lesion. A reversible lesion cannot be produced by this technique. Such lesions may have further clinical or experimental value. The local application of radioactive isotopes to specific areas of the brain under controlled situations permitting withdrawal of solutions may be possible by this met

ISSN:0003-276X    

DOI:10.1002/ar.1091490103

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

年代:1964

数据来源: WILEY

摘要:

AbstractA light and electron microscopic study of the early changes which occur in cadmium necrosis of the testis of the mouse was made in an effort to identify the site of action of cadmium. Mice were given a single, intraperitoneal injection of 1% CdCl2at a dosage of 0.1 ml/10 g body weight and then the testes were fixed for light and electron microscopy at various hourly intervals. The earliest changes which were appreciated by light microscopy consisted of an edema of the intertubular spaces, congestion of blood vessels, and an increased amount of granular precipitate in the connective tissue spaces. By electron microscopy the earlies changes were observed in the endothelium of the testicular vascular bed and consisted of a striking and rapid increase in the prevalence of pinocytotic vesticles suggesting an increased interchanges of fluid between the blood and extravascular spaces. All of these changes preceded any appreciable alteration in the cells of the seminal epithelium. The fact that the earliest alterations are observed in blood vessels suggests that the site of action of cadmium in the production of testicular necrosis is upon the endothelium of the vascular bed.A comparative series of animals (frog, pigeon, rooster, armadillo, opossum) was also investigated as to their susceptibility to the toxic effects of cadmium. the results from these species, and other species reported by previous investigators, suggest the generality that cadmium necrosis is a phenomenon common to species possessing scrotal testes and absent from those possessing abdominal testes. The opossum is an exception to this generality. These findings are discussed in relation to the blood supply of the testis.

ISSN:0003-276X    

DOI:10.1002/ar.1091490104

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

年代:1964

数据来源: WILEY

摘要:

AbstractFirst, using the methods of H3‐thymidine autoradiography and counting mitotic index, cytokinetics of the matrix cells were studied in the telencephalon of normal mouse embryos at ten‐days‐postconcetpion, and various kinetic constants of the matrix cells were determined: Generation time, five hours 20 minutes; mitotic duration, 24 minutes; presynthetic resting time, two hours 36 minutes–one hour 36 minutes; DNA synthetic time, one hour 20 minutes; and post synthetic resting time, one‐two hours. Based on this information, effects of two teratogenetic agents, x‐rays and thio‐TEPA, on the cellular proliferation were analyzed. By x‐ray irradiation (200 r) only proliferating matrix cells are damaged in the neural tube, but not neuroblasts. The radiation induces a temporary block of the flow of the matrix cells through the cell cycle at the latet2period so that the mitotic and DNA synthetic cells subsequently decrease in number. Some of the matrix cells that are captured att2period fail to tolerate the block, degenerate and are eliminated from the matrix layer. On the other hand, thio‐TEPA, which was proved non teratogenetic to the C. N. S. in this experimental condition, causes a slight prologation oft2duration, but does not significantly influence the proliferative process i

ISSN:0003-276X    

DOI:10.1002/ar.1091490105

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

年代:1964

数据来源: WILEY

摘要:

AbstractA purified diet lacking folic acid and containing 20 mg% of the antimetabolite, 9‐methyl pteroylglutamic (folic) acid was fed to female Long‐Evans rats during days eight and nine of pregnancy. Embryos were removed at autopsy on the tenth day of gestation for study and comparison with embryos from normal control pregnancies.Analysis of mitotic counts revealed that 18.6% of the cells in control embryos were in mitosis in contrast to only 5.7% in PGA‐deficient embryos. A disproportionate reduction in anaphase and telophase stages was observed in conjunction with an increased percentage of cell at metaphase. Concomitantly with these mitotic changes a marked reduction in histochemically demonstrable RNA and in numbers of ribosomes as revealed by electron microscopy was obs

ISSN:0003-276X    

DOI:10.1002/ar.1091490106

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

年代:1964

数据来源: WILEY

摘要:

AbstractA simple, rapid method is presented which permits qualitative evaluation of osteogenesis in tissue culture. Eleven‐day embryonic chick tibiae, with distal and proximal condyles removed, were grown in organ culture for two weeks. Explants demonstrated subperiosteal osteogenesis, bridging of fracture defects, and formation of bone,de novo, over the cut cartilaginous end surfaces of explants.The method presented herein has several advantages over those previously described and may be adopted for anin vitroassay of materials to determine direct effects on osteogenesis. Large quantities of explants can be prepared easily and cultured to yield consistantly abundant quantities of osteoid. Bone which is formed over ends of anlage is particularly significant by virtue of its position. New bone formed elsewhere in explants, with the possible exception of the fracture sites, however, is difficult to distinguish from bone present before onset of cultivation. Further more, osteogenesis which occurs over the cut cartilaginous ends after a week of culture, probably results from favorable environmental conditionsin vitroand not from cellular activity “preprogrammed”in ovo.In addition to osteogenesis, alteration of cartilage cells and matrix were observed in this system. Chondrocytes in the cut ends of the anlagen became spheroidal and resembled osteoblasts. Bone formation, however, was not observed about these cells. In and about lacunae of degenerating chondrocytes at the ends of the anlagen, collagen fibers app

ISSN:0003-276X    

DOI:10.1002/ar.1091490107

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

年代:1964

数据来源: WILEY

摘要:

AbstractThis study points out a heretofore unrecognized range of variation in the mastoid area, between modern and ancient man. The mastoid region of modern man was re‐investigated and found to present a very different picture from fossil man. A trend was noted in modern man toward the enlargement of the mastoid process, the eruption of the juxtamastoid process in the digastric fossa and the absence of a pronounced occipitomastoid crest. The conditios were considerably differnt in Neanderthal man. In this group the area consisted of a small mastoid process, a spacious digastric fossa with no intervening juxtamastoid process and an occipitomastoid crest which exceeded or at least equaled, the projection of its mastoid process.This additional data emphasizes the cranial differences between modern man and Neanderthal man and suggests that the region should be re‐evaluated in light of this new d

ISSN:0003-276X    

DOI:10.1002/ar.1091490108

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

年代:1964

数据来源: WILEY

摘要:

AbstractThe adrenal cortex of the male guinea pig has been examined with the electron microscope. Many of the cells of the zone glomerulosa possessed bizarreshaped nuclei with frequent cytoplasmic invaginations. The internal structure of the mitochondria was entirely cristaform, the cristae being spaced at reasonably regular intervals. A rough‐surfaced endoplasmic reticulum was present in this zone only. The outer fasciculata showed an abundance of lipid in droplet from. The mitochondrial internal structure of this zone was predominantly cristaform, but the cristae were aggregated in clumps instead of being evenly spaced. Smooth‐surfaced cytoplasmic vacuoles were frequent. The inner fasciculate and the reticularis were generally similar. They differed from the above zones in that little lipid was present in droplet form and by the presence of a profusion of smooth‐surfaced cytoplasmic vacuoles which were interpreted as being homologous with the agranular endoplasmic reticulum. Mitochondria of the inner fasciculata were irregular in shape, while those of the reticularis were larger and more regular. In all zones of the cortex, the vascular channels were lined with an endothelium separated from the parenchymal cell by a space which was frequently seen to contain fibrils as well as fibroblast‐lik

ISSN:0003-276X    

DOI:10.1002/ar.1091490109

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

年代:1964

数据来源: WILEY

摘要:

AbstractVital staining by trypan blue was used to demonstrate macrophages within involuting (post‐secretory), lactating and resting mammae of mice. Involution was produced by removal of the nursing young on the eighth day post‐partum when maximal lactation was present. The number of macrophages in involutin mammae was not significantly greater than that found in the rsting glands of mice receiving comparable injections of dye. Macrophages (coarse, granular accmulations of trypan blue in cytoplasm) in involutin mammae were congregated around and within atrophic alveoli and small ducts, while in lactating and resting mammae they were located primarily in the areolar stroma. Plasma cells, lymphocytes and neutrophils were increased during involution, but the limited leucocytic response did not indicate that a significant inflammatory reaction was active in the process of involution. Difuse parenchymal staining, indicating cellular injury or death, was limited to the epithelium of necroptic ducts and alveoli of involuting glands. Granular deposits of dye, as in macrophages or renal tubular epitelium, were not seen in the resting, lacating or involuting mammary parench

ISSN:0003-276X    

DOI:10.1002/ar.1091490110

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

年代:1964

数据来源: WILEY

摘要:

AbstractThe right knees of rabbits were rigidly fixed with metal clamps midway between full flexion and full extension. After six dayas the knees of six were preserved while clamped. Twenty other rabbits were sacrificed after 16 days. Ten received colchicine on the eighth, eleventh and fifteenth day following clamp application. Their knees were preserved after clamp removal. The femoral and tibial articular cartilages subjected to pressure for six days were extremely compressed but viable. In knees clamped for 16 days the changes found were related to the amount of knee movement present at autopsy. Where it was small but easily detectable the cartilages were normal. Where there was no movement the cartilage was dead. Where it was only slight variable cartilage changes were found ranging from surface abradement, Matrix swelling, enlargement of lacunae and chondrocytes, increased number of cells per lacuna, and an occasional chondrocyte in mitosis, to an extensive matrix alteration resulting in the disappearance of lacunae, chondrocytes released from the confines of lacunae and interspersed among a meshwork of fine collagen fibers, and a few released chondrocytes in mitosis. The most extensive change was where the cartilage defect area was occupied by a mass of proliferating richly‐cellular tissue. The knee articular cartilage changes of this experiment are compared with those occurring during pregnancy in the pubic symphyseal cartilage of mic

ISSN:0003-276X    

DOI:10.1002/ar.1091490111

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

年代:1964

数据来源: WILEY