摘要:

AbstractThe number of neurofilaments and microtubules present in nerve fibers was determined for sciatic nerves from adult mice and from rats of three different ages. More microtubules than neurofilaments were found in nonmyelinated fibers; the ratio of tubules/filaments was reversed in myelinated fibers and was found to change with axon caliber independent of the presence of a myelin sheath. A series of regression analyses indicated that axon caliber correlates best with the sum of the number of neurofilaments and microtubules per fiber. This correlation was only slightly better than that for neurofilaments alone. Axon caliber also correlated better with the filament‐tubular material than with the thickness of the myelin sheath. The results were similar for both rats and mice, and age differences were not apparent in the samples of nerves analyze

ISSN:0003-276X    

DOI:10.1002/ar.1091670402

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe extracellular alveolar lining layer (ALL), composed of both surface film and hypophase, is described under different conditions and fixatives.With primary osmium fixation of small blocks the ALL is not preserved. Lamellar and homogeneous osmiophilic bodies are scattered at random within alveoli. Occasionally the surface film remains within an alveolus but the hypophase is not seen. Poor preservation of the ALL is thought to be due to the limited ability of osmium to cross link proteins and to the mechanical deformation of the alveoli which inevitably accompanies the cutting of fresh lung into small blocks. This leads to the escape of alveolar air and a loss of the air‐liquid interface.With primary glutaraldehyde fixation of the whole lung, the ALL is well preserved in many alveoli. The hypophase is mostly homogeneous but occasionally contains osmiophilic bodies and lattices. There are no lamellar and homogeneous osmiophilic bodies within the air space of the alveoli when the ALL is preserved, which suggests that primary osmium fixation of tissue leads to the dislodgement of these osmiophilic bodies from the hypophase.The electron densities of the surface film, the hypophase and the capillary fluid are alike in a given preparation but vary considerably with the concentration of the glutaraldehyde solution and the buffer vehicles used. It is pointed out that in phosphate‐buffered preparations the hypophase, the basement membrane and the capillary fluid are highly electron‐dense which makes difficult the localization of an electrondense tr

ISSN:0003-276X    

DOI:10.1002/ar.1091670403

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

年代:1970

数据来源: WILEY

摘要:

AbstractA diversity of cell types have been found in the pancreatic islets of three species of Amphisbaenidae in a light and electron microscopic investigation. The A cells have been characterized as having phosphotungstic acid hematoxylin and orange G positive secretory granules which are electron opaque and 450–500 mμ, in diameter. The B cells possess aldehyde fuchsin reactive granules which are slightly larger than A granules, approximately 550 mμ, and have a variety of profiles in the electron microscope. The D cells are characterized as being fast green positive and argyrophilic in the light microscope, and in the electron microscope have small, 200–300 mμ, secretory granules with a core of moderate electron opacity. In D cells the Golgi apparatus is more highly developed than in A or B cells.Bipesislets contain a presumptive fourth cell type possessing large secretory granules with irregular profiles and focal internal densities. An additional cell type, found inAmphisbaena manniandBipes, has small, electron opaque gr

ISSN:0003-276X    

DOI:10.1002/ar.1091670404

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

年代:1970

数据来源: WILEY

摘要:

AbstractThe histochemistry of developing connective tissues and its relation to early connective tissue fibrils was investigated in the perinotochordal area of the chick embryo. Chick embryos were sacrificed at one, two, three, four, six and ten days of incubation and were prepared for both light and electron microscopy. Five histochemical stains (PAS, alcian blue, Hale colloidal iron, metachromatic toluidine blue, methenamine silver) were used to demonstrate polysaccharides, mucoproteins and mucopolysaccharides. Mature connective tissue elements were demonstrated by Mallory's connective tissue stain and Weigert's resorcin‐fuchsin stain. Routine electron microscopic techniques served to demonstrate extracellular connective tissue fibrils.The first positive response for all histochemical stains occurs on the third day of incubation. Moderate microfibrillar growth precedes this by one day. Light microscopic staining patterns differ from electron microscopic fibrillar arrangements. In the perinotochordal area microfibrils later contribute to the cartilaginous model of the future vertebral body. By the sixth day, dense microfibrillar concentrations appear in the precartilage area where acid mucopolysaccharides are intensely concentrated. Staining for mature connective tissue fibrils does not occur until the tenth da

ISSN:0003-276X    

DOI:10.1002/ar.1091670405

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

年代:1970

数据来源: WILEY

摘要:

AbstractIn cementum of rat molars, the cementoblasts were found to differ from pre‐cementoblasts in having an increased granular endoplasmic reticulum, greater number of polyribosomes and denser material in the cisternae of granular E. R. as well as in the general cytoplasm. The cementocytes with maturation showed a gradual decrease in the size of the Golgi complex and the granular endoplasmic reticulum. On the other hand, an increase in the number of lysosomes was observed. Parallel with these intracellular changes, the pericullular space became irregular in width, its fibrillar material became replaced by a flocculent material. Ocasionally, structurally different matrix was seen. At the cemento‐dentinal junction the cementocytes showed degenerative changes indicative of degeneration and death. The epithelial cells, remnants of Hertwig's root‐sheath, some of which get enclosed in the cementum, accumulated filamentous material as well as spheres of amorphous substance. These cells eventually degenerated, leaving their debris in the lacunae. The degeneration of epithelial cells did not seem to affect the cementum matrix in their immediate vicinity. Some collagen fibrils of the cementum, seemed to differ structurally from those of the periodontal membrane. Thin fibrils, about 160 Å in diameter, were also observed in the ce

ISSN:0003-276X    

DOI:10.1002/ar.1091670406

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

年代:1970

数据来源: WILEY

摘要:

AbstractConcentrations of hypophyseal and plasma luteinizing hormone (LH) and follicle stimulating hormone (FSH) were measured along with the total amount of uterine DNA and RNA during four stages of the mouse estrous cycle: proestrus, estrus, metestrus, and diestrus. Female mice were exposed to male olfactory stimuli to induce repeatable 4–5 day estrous cycles. The mean concentration of hypophyseal LH dropped from 2.9 μg/mg at diestrus to 0.3 μg/mg at proestrus. During this same time period the concentration of plasma LH increased from 3.3 μg/100 ml to 10.6 μg/100 ml. In contrast to the fluctuations in LH, the concentration of FSH in the hypophyses and plasma remained relatively constant throughout the estrous cycle. Uterine weight and total uterine DNA, RNA, and the ratio of RNA:DNA were all significantly greater (P<0.05) at proestrus than at metestrus suggesting significant fluctuations in cell numbers and protein synthetic activity of the uterus during the estrous cycle. The fluctuations in LH and FSH release and in uterine nucleic acids noted during the mouse estrous cycle generally agree with observations in laboratory rats. However, the pattern of LH and perhaps FSH release preceding ovulation in mice may be different than that suggested for rats. These differences may be attributed to the greater dependence of mice on male olfactory st

ISSN:0003-276X    

DOI:10.1002/ar.1091670407

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

年代:1970

数据来源: WILEY

摘要:

AbstractBrunner's glands of the echidna form a thick, interwoven collar confined to the submucosa of the most distal portion of the stomach. The glandular mass ends immediately proximal to the pyloroduodenal junction and empties onto a surface lined by stratified squamous epithelium. Histochemical studies indicate that the secretion elaborated by the glands is an acid mucopolysaccharide.Secretory tubules in the glands consist of large, pyramidal‐shaped cells resting on a delicate basal lamina. They contain large, pale or granular secretory droplets which are membrane bounded and are found in close association with extensive Golgi complexes and also at the apex of the cells. Secretary granules, occasionally fused into irregularly‐shaped complexes in the apical region, appear to rupture the cell membrane and discharge their contents into the adjacent lumen. Small, dense granules are also present but less abundant. The granular endoplasmic reticulum is confined mainly to the perinuclear region and comprises dilated cisternae containing amorphous material. Several small vesicles apparently formed from smooth membrane areas of the ergastoplasm are seen adjacent to the Golgi networks.The epithelium lining the duct is devoid of large secretory granules and contains relatively few organel

ISSN:0003-276X    

DOI:10.1002/ar.1091670408

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

年代:1970

数据来源: WILEY

摘要:

AbstractSingle submandibular glands were isografted intraperitoneally to normal BALB/c mice. From the day following transplantation, 20 mg testosterone enanthate fortnightly, or daily intraperitoneal injections of 0.25 mg per gram body weight of isoproterenol‐HCl were given. Control mice were untreated. The grafts were removed from five mice in each group 1, 2, 4, or 8 weeks after grafting. Regardless of treatments, only ductal cells were observed one week after transplantation. With testosterone treatment for longer than two weeks, their remaining ductal cells tended to accumulate secretory granules. Some appeared to be secretory tubules resembling those in the glands of normal adult male mice. When the glands were transplanted from females to male hosts, surviving grafts responded to endogenous androgen of the hosts, and some secretory tubules reappeared without testosterone treatment. Contrarily, with isoproterenol treatment for longer than two weeks, acinar cells reappeared in the grafts, but no secretory tubules were observed. The remaining ductal cells often underwent hyperplastic changes with reappearing tubules or acinar cells amongst them corresponding to post‐transplantational treatment. Mechanisms of differentiation of these three different components of submandibular glands were found to be different and each had specific affinity to testosterone or isoproterenol. Grafts were removed from hosts treated with testosterone for two months, and when 4 or 8 of these grafts were retransplanted into each new host, they demonstrated a lethal eff

ISSN:0003-276X    

DOI:10.1002/ar.1091670409

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

年代:1970

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091670401

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

年代:1970

数据来源: WILEY