摘要:

Longitudinal and transverse tooth sections oïhums oxyrinchus were serially etched in 2.6% nitric acid. The changing optical properties of the etched surfaces were observed during the serial etchings, and the descent of the enameloid surfaces was measured. Shark enameloid seems to be less effectively etched by acid than human enamel; this difference may be due to differences in solubility between fluorapatite and hydroxyapatite. Most of the information regarding the structure of the enameloid was gained during the first five of ten etchings. The reflection of light from the surface was influenced by the orientation of the crystallites, longitudinally sectioned crystallites reflecting the light better than transversely sectioned crystallites. The dentinal extensions were continuous with and of the same structure as the underlying dentine. The radial fibers originated from the dentinal extensions, and they both contained organic material and were accompanied by crystallites. When the specimens were imbibed with water the distinctness of the dentinal extensions and radial fibers was improved

ISSN:1422-6405    

DOI:10.1159/000145101

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Argentophil neuronal perikarya and perikaryal neurofibrils similar to those illustrated in Ramon y Cajal’s classical studies have in the present investigation been found to be manifestations of the chromophil neuron. Conclusive evidence of such association was obtained by silver impregnation with the Bodian technique of sections previously stained with cresyl violet. Regardless of the fixative used, silver-impregnated neurofibrils were evident when (1) normal tissues were fixed by immersion or unsuccessfully fixed by perfusion, (2) normal tissues were exposed and touched after death but before perfusion with the fixative, or (3) flow of perfusates was compromised by the effect of an experimental procedure, as well as when (4) a hypertonic saline solution was used in the first perfusate. These cytologic peculiarities were still discernible after 24 h of postmortem autolysis following a delay in removal of the brain or in immersion of the exposed brain in the fixative. After immersion fixation, argentophilia and chremophilia occurred ubiquitously in the brain of the newborn guinea pig; however, argentophil neurofibrils were noted in the absence of chromophil neurons in the brain stem of the newborn rat, rabbit and cat. After fixation by perfusion, perikaryal neurofibrils were not impregnated in either newborn or old animals or in animals with facial nerve transection. Affinity for Congo red or bire-fringency, exhibited by neurons with marked neurofibrillary changes in human senile brain atrophy, were absent in the present material. On the basis of the current light-microscopic observations, it is concluded that argentophilia of neuronal perikarya and perikaryal neurofibrils is another manifestation of the chromophil neuron induced by postmortem trauma and of the ocellate neuron elicited by perfusion with hypertonic salin

ISSN:1422-6405    

DOI:10.1159/000145102

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The anatomy of the external anal sphincter was studied in 20 adult human cadavers of both sexes by dissection and histological examination. The external anal sphincter is not naturally divided into layers or laminae. The lowermost muscle bundles differ from the main part in being completely surrounded by thick fibrous tissue septa derived from the longitudinal anal coat. The perineal branch of S4 supplies the posterior third, the inferior haemorrhoidal nerves supply the anterior two thirds. All fibres of the sphincter retain their skeletal attachment to the anococcygeal ligament to the coccyx. Some fibres cross the median plane to be continuous with the transversus perinei of the opposite side. A cleft was displayed separating the lower border of the levator ani muscle from the upper border of the external anal sphincter. The muscle bundles of the sphincter are arranged circumferentially in one continuous circle and not in loops. Fibres from the anterior border of the levator ani muscle extend to cover and blend with the outer surface of the external sphincter in their way to the anococcygeal ligament.

ISSN:1422-6405    

DOI:10.1159/000145103

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The cephalic arterial pattern in edentates and pangolins is described on the basis of 9 corrosion specimens, representing all the classical superfamilies, with special reference to their phylogenetic relationship and taxonomy. In this respect, the importance of the manner in which the external carotid artery system annexes the stepedial area of supply and of the course of the internal carotid artery in relation to the tympanic cavity is emphasized. The investigation does not indicate any special relationship between the New World edentates and the Old World pangolins, whereas the marked difference in the course of the internal carotid artery in recent edentates stresses the independent development of the South American anteaters compared with that of the two other edentate groups (armadillos and tree sloths). Most probably the edentates were divided very early into two main lines which have evolved independently since the early Tertiary, i. e. one for the anteaters and one for the tree sloths and armadillos, indicating a probable subdivision of the true edentates into two suborders. This subdivision is markedly different from the classical two-fold division of the edentates.

ISSN:1422-6405    

DOI:10.1159/000145104

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Two earlier theories on the effect of vibrissae removal in rats were tested. One theory stating that vibrissae removal produces impairment of spatial orientation capacity was confirmed. The other stating that it causes a depressive state of hopelessness and sudden death could not be confirmed. It is concluded that the extrapolation from the particular animal experiment to human psychological processes is not justified.

ISSN:1422-6405    

DOI:10.1159/000145105

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Electron-microscopic studies were made on the parathyroid gland of cadmiumtreated mice. Most chief cells in treated mice were rich in free ribosomes and secretory granules compared to the control mice. In the parathyroid gland after 3 and 4 weeks of administration of cadmium, interdigitations between adjacent chief cells became more complex than in the control mice. In most chief cells of the parathyroid gland after 2, 3 and 4 weeks of administration of cadmium, the Golgi complexes associated with numerous prosecretory granules were better developed than in the control mice. These ultrastructural appearances suggest that parathyroid gland cellular activity was stimulated in response to cadmium treatment.

ISSN:1422-6405    

DOI:10.1159/000145106

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The-funicular part of the ligamentum nuchae of Bos indicus attaches to the dorsolateral edges of the bifid spines of the seventh thoracic through third lumbar vertebrate. Cranially, the funiculus nuchae runs freely medial to the deep thoracic fascia which separates it from the overlying rhomboideus thoracis. The zebu hump is composed primarily of rhomboideus cervicis which in the thoracic position is clearly separable from underlying structures.

ISSN:1422-6405    

DOI:10.1159/000145107

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The venous drainage of the urinary bladder was studied in 20 pelvic halves (14 males and 6 females). Vesical and prostatic plexuses draining the bladder (vesical only in females) were found in 16 cases; they supplied blood to the internal iliac vein – usually by two to five veins – the most common number being three. One vein always drained the prostatic plexus. The vesical and prostatic plexuses were absent in 4 male cases, where the vesical veins issuing from the bladder wall drained directly the internal iliac vein. Their number in such cases was minimal : between one and two only, on each side. The union of a vesical vein issuing from any of the two mentioned plexuses (when found) with the obturator, prostatic or vaginal vein was common. A shunt from a common trunk of united obturator and vesical veins to the external iliac vein was noticed in some cases. Occasionally, an inferior vesical vein ending in the obturator vein accompanied an inferior vesical artery initiating from the obturator art

ISSN:1422-6405    

DOI:10.1159/000145108

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The histology and mucosubstance histochemistry of the ferret lingual glands were studied. Both serous and mucous minor salivary glands were present in the posterior part of the tongue. In serous glands, acinar cells and a very few cells of the excretory ducts contained granules which gave reactions for neutral mucopolysaccharides only. The mucous glands, including the duct system, contained mainly weakly sulphated acidic mucin, some neutral mucin but no carboxylated mucin. Occasional goblet cells were present in the excretory ducts of both serous and mucous glands. They contained weakly sulphated mucin.

ISSN:1422-6405    

DOI:10.1159/000145109

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Buffalo and Fisher inbred rats and their F1–F4 hybrids were exposed to heat, 96 °F and 30% humidity, at 35 days of age. Fisher rats which are of lighter weight survive significantly longer than Buffalo rats which are heavier. Body weight was significantly depressed in all hybrids. Only in F2 hybrids was heat tolerance similar to that of the Fisher inbreds. In all other hybrids, it was lower. No heterosis was found under the conditions us

ISSN:1422-6405    

DOI:10.1159/000145110

出版商:S. Karger AG    

年代:1979

数据来源: Karger