摘要:

AbstractThe plantar sweat glands of the rat have been studied by light and electron microscopy. These glands differ from conventional eccrine sweat glands of man, other primates, and cats in that the secretory segment contains only one type of secretory cell. This cell is characterized by a relatively nondescript cytoplasm containing numerous vesicles, extensive interdigitations of adjacent plasma membranes and small microvilli projecting into the lumen. In the resting gland, two types of cells can be distinguished on the basis of mitochondrial morphology. Some cells contain mitochondria in condensed configurations, and others contain mitochondria in the more orthodox configuration. Following stimulation, these differences are not pronounced; and the condensed mitochondria have evidently changed into more orthodox mitochondria in appearance. No distinct cytologic pathway for secretion could be defined, correlated with the most unusual ionic composition of the sweat in this animal (very high levels of potassium). The sweat glands of the rat foot pad then are unique as compared with other cutaneous glands both in their cytologic appearance and in the chemical composition of the sweat they elaborate.

ISSN:0003-276X    

DOI:10.1002/ar.1091690102

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe incidence and patterns of association of tendon organs (TO's) with muscle spindles was studied in serial histological sections of the extensor digitorum brevis (EDB) muscles of an adult cat. Some observations were obtained from the medial gastrocnemius and soleus muscles of a second cat, and the EDB muscle of a two‐toed sloth. An intimate relation of a TO to a nearby spindle, wherein the “spindle tendon” passes alongside the TO to attach to the aponeurosis, was found for 50% of cat EDB TO's, and 20 to 25% of the TO's in the other muscles. In cat EDB samples both TO's and spindles found in “tendon organ‐spindle dyads” had larger cross‐sectional areas at the equator than “solitary” units, and dyad TO's received the attachments of more extrafusal fibers than did solitary TO's. A number of the “solitary” TO's were found to be in line at a greater distance with spindles that lay along the extrafusal fibers inserting onto the TO. The possible developmental and functional significance of these

ISSN:0003-276X    

DOI:10.1002/ar.1091690103

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe principal intrinsic ganglion sites in the human infant's heart have been described. They are arranged in six main groups. While most ganglia are associated with the atria, ventricular neurons have also been identified and their significance regarding possible ventricular parasympathetic innervation is discussed. The ganglia vary considerably in size, with most of the larger ones lying on the superior aspect of the heart near the superior vena cava, the aorta and pulmonary artery. They all possess well‐defined capsules. Most of the contained neurons appear to be multipolar, but pseudounipolar and occasional bipolar forms have been detected. Two plexuses exist in the parietal pericardium. Large complicated nerve endings described by previous writers have not been identified, but free endings might exist. Networks in the subepicardium, subendocardium and associated with the coronary arteries have been demonstrated and their functional significance is discussed. Nerve endings, either simple or complicated, were not seen in relation to these plexuses in this investigatio

ISSN:0003-276X    

DOI:10.1002/ar.1091690104

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

年代:1971

数据来源: WILEY

摘要:

AbstractEggs ofAmbystoma maculatumwere separated into three groups and maintained at 5°, 8° and 14°C, respectively, until stage 27. At this stage the otic vesicle was extirpated from the right side, thus eliminating the VIIIth cranial ganglion and root. The number of cases in which Mauthner's cell (MC) failed to differentiate in the absence of VIIIth roots was compared among the three temperature groups.In a total of 713 animals, MC was absent on the side of operation in 200 cases (28.05%). Comparison of the three temperature groups with respect to the absence of MC is as follows: 14°, 39 of 212 cases (18%); 8°, 83 of 266 cases (31%); 5°, 78 of 235 cases (33%). Statistical analysis of these data demonstrates a significant difference between either one of the colder groups and the 14° group with regard to suppression of MC. When the two colder groups are tallied as a single sample, the difference is even more significant. There is no significant difference between the 5° and 8° groups. These results indicate that the differentiation of MC is more dependent upon the ingrowth of VIIIth root fibers when morphological development has been delayed by prolonged hyp

ISSN:0003-276X    

DOI:10.1002/ar.1091690105

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

年代:1971

数据来源: WILEY

摘要:

AbstractChick embryo spinal cord has been explanted at two‐day stages, when few or no cells have formed axons, and cultured for five to seven days. The effects of various culture methods and the presence or absence of other tissues on differentiation have been studied. Many cells with axons and numerous nerve fibers were seen in silver‐stained sections of completely isolated neural tube cultured in a fold of vitelline membrane, as well as in neural tube explanted with adjacent tissues and in isolated neural tube recombined with somites. Electron micrographs of corresponding cultures showed cell bodies similar to those of fairly early nerve cellsin vivoand processes with the structure of axons. Some characteristic differences in cell fine structure and in histological organization among these types of cultures were observed. Isolated neural tube cultured directly on a millipore filter did not survive or differentiate as well. These observations indicate that initial phases of nerve cell differentiation can proceed in organ culture and that there is no specific requirement for interaction with adjacent mesodermal tissues. This system can be used profitably for further investigation of factors controlling various aspects of differentiation in the central nervous sys

ISSN:0003-276X    

DOI:10.1002/ar.1091690106

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

年代:1971

数据来源: WILEY

摘要:

AbstractIn the head process to early head fold stage chick embryo, the cells which will form the pulmonary veins are located in the mesoderm near the posteromedial edges of the heart‐forming regions. At the 26 somite to early limb bud stage, the presumptive pulmonary vein cells have been folded to the midline of the embryo as part of the splanchnic mesoderm and form the endothelial plexus which courses through the dorsal mesentery of the sinoatrial region of the hear

ISSN:0003-276X    

DOI:10.1002/ar.1091690107

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe intracellular distribution of mucosubstances in the acinar cells of the rat sublingual gland has been studied at the electron microscopic level by means of two histochemical techniques: PA‐silver methenamine for the detection of vicinal glycols and colloidal thorium for the detection of polyanions. By both methods the secretory granules in the mucous acinar cells were selectively stained. The reaction products were visualized as dense closely packed precipitates covering the entire matrix of the individual mucous granules. Similar reaction products were also often observed within the Golgi apparatus of the mucous cells. In striking contrast, the secretory granules and Golgi apparatus of the demilunar cells exhibited no demonstrable selective staining by either method. It is concluded that the secretory granules of the mucous acinar cells are largely composed of mucosubstances containing vicinal glycols and polyanions and that the secretory granules in demilunar cells contain no demonstrable content of such mucosubstance

ISSN:0003-276X    

DOI:10.1002/ar.1091690108

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

年代:1971

数据来源: WILEY

摘要:

AbstractA simple method forin vitrostudies of human subcutaneous adipose tissue is described. Explants of adipose tissue have been maintainedin vitrofor 30 weeks in Parker medium 199. The morphology of cultured explants compared well with that of freshly excised specimens. In the absence of serum there was no outgrowth of fibroblast‐like cells. When human serum was added to the medium at concentrations exceeding 5% there was a proliferation of fibroblast‐like cells. This cell proliferation could still be obtained when serum was added after two weeks of culture in a serum free medium. The adipose cells were isolated with collagenase and the cell size determined. Explants with an initial mean cell size larger than about 95 μ showed a significant decrease in cell size during the incubation. This could not be attributed to a traumatic effect. Metabolic differences between large and small adipose cells was suggested as a possible re

ISSN:0003-276X    

DOI:10.1002/ar.1091690109

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

年代:1971

数据来源: WILEY

摘要:

AbstractInvestigations were made on the morphological and histochemical nature of the ellipsoid sheaths of two different types of spleens, sinusal and non‐sinusal, as found in the dog and cat respectively.Ellipsoid cells of dog and cat spleens respond similarly with Marshall's silver impregnation method as well as demonstrate activity for the hydrolytic enzyme, acid phosphatase. Both technics substantiate ellipsoid involvement in the reticuloendothelial system. Nonspecific esterase, another hydrolytic enzyme commonly found in phagocytic cells, was demonstrated in the cat ellipsoid cells but not in similar cells of the dog spleen indicating a basic difference in the physiological activity of the dog and cat ellipsoid cell

ISSN:0003-276X    

DOI:10.1002/ar.1091690110

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

年代:1971

数据来源: WILEY

摘要:

AbstractThe fine structure of the interstitial cells of Leydig has been examined in the squirrel monkey,Saimiri sciureus, during the non breeding portion of the year when the testes are essentially azoospermic. Interstitial cells are present in abundance as a layer, several cells thick, on the inner aspect of the tunica albuginea. Cytologically, the cells possess the characteristics usually associated with cells which synthesize and secrete steroid hormones: an abundant agranular endoplasmic reticulum in the form of anastomotic tubules; mitochon‐chondria with both lamellar and tubular cristae; only a few strands of granular endoplasmic reticulum; a Golgi apparatus and associated vesicles, some of which are of the coated variety; a varying population of lipid droplets and dense bodies. Some of the dense bodies appeared to be lipofuscin pigment. A previously undescribed inclusion was frequently encountered which consisted of arrays of a honeycomb like structure. Most frequently these structures were present near the cell periphery or in blunt protrusions of the cytoplas

ISSN:0003-276X    

DOI:10.1002/ar.1091690111

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

年代:1971

数据来源: WILEY