摘要:

Scanning electron microscopy studies of decalcified human secondary osteons were conducted to determine correlations in fiber orientations in these osteons with their appearance under crossed polaroids. Using a new sample preparation technique, osteons were prepared to expose many of their lamellar interfaces. By studying many such samples, it was concluded that osteons which appear ‘dark’ under crossed polaroids contain fibers with orientations having little or no transverse component, whereas ‘bright’ osteons possess fiber orientations with transverse and longitudinal components. ‘Intermediate’ osteons have been found to contain fiber orientations richer in longitudinal component than in

ISSN:1422-6405    

DOI:10.1159/000144772

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

On eight brains of wild boars, the appearance of the exterior and interior brain structures was studied. The brain was preserved in the skull by formalin solution injection into the carotid artery. After having been set up for 4 months in a 5% formalin solution, the brain was removed in conjunction with the coverings. Subsequently, the brain was preserved in 5% formalin for 2 months. By careful dissection and elaboration of special preparations, the appearance of the grey and white substance of the brain, of the basal ganglia and of certain portions of the limbic system was studied. On the frontal and horizontal sections of the brain the appearance of the brain matter, of the basal ganglia and of the brain ventricles was studied. The exterior and interior morphology of the cerebellum was investigated on special preparations.

ISSN:1422-6405    

DOI:10.1159/000144773

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

A simplified and inexpensive grid apparatus for use with the differential point counting technique of stereological analysis of cellular and organellar volumes is described.

ISSN:1422-6405    

DOI:10.1159/000144774

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

This paper describes the fine structure of the rabbit connective thecal cells in the developing corpus luteum 20 h after mating. These cells are characterized by an irregularly shaped soma containing the nucleus and the bulk of organelles and many thin and long prolongations. The observations reported here suggest that the migratory movements of the front thecal cells could be mediated by an anchoring contraction machinery of the cell prolongations.

ISSN:1422-6405    

DOI:10.1159/000144775

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The tubule-like cells (TLC) of the parietal layer of the Bowman’s capsule of the renal corpuscle in normal male mice are provided with bundles of thin microfilaments (50–70 Å). Moreover, the ultrastructural observations demonstrated that similar thin filaments (50–70 Å) are located in the flattened cells of the parietal layer of the Bowman’s capsule and in the tubular cells. All the above cells bind antimyosin-like antibodies. Considering the correspondence between the immunochemical and ultrastructural findings, it is suggested that the microfilaments located in TLC contain a ‘myosin-li

ISSN:1422-6405    

DOI:10.1159/000144776

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Male rats of 150 g body weight were given restricted amounts of their normal diet up to the age of 85 weeks, such that they showed no significant change in body weight. They were then rehabilitated by allowing them unlimited access to the normal diet. During rehabilitation, the experimental rats reached a maximum body weight that was only 70% of that normally attained. Body length, however, exhibited better recovery, the experimental animals achieving 96% of the normal body length. The skeleton continued to grow during the first 7 weeks of undernutrition, but thereafter only the caudal half of the pelvic girdle continued to grow. On rehabilitation all skeletal dimensions increased, and all eventually reached the normal range of mature skeletal dimensions. Although the pelvic girdle returned to a normal size, it still manifested some alterations in shape.

ISSN:1422-6405    

DOI:10.1159/000144777

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The height of the vertebral growth zones of 13 adolescents dying between the ages of 13 and 18 years was determined with the aid of an eyepiece micrometer. In addition, the proportion ‘total of widths of chondrocyte columns/diameter of the growth zone’ was established. In the cervical spine, the growth zones of the caudal end plates were significantly higher than those of the cranial end plates. The reverse was true for the thoracic vertebrae. In the lumbar spine, however, conditions resembled those found in the cervical spine in that the caudal end plates were higher than those of the cranial plates; yet, there was no statistically significant difference in the relative quota ‘chondrocyte columns/diameter of growth zone’ in this segment of the spine. These results suggest that lengthwise growth of cervical and lumbar vertebrae is more marked in the caudal than in the cranial end plates, whereas, in the thoracic spine, growth of the cranial exceeds that of the caudal end plates. Moreover, the height of the growth zones increases in a craniocaudal direction, a fact which could be related to the more marked growth of lumbar as compared to cervical or thoracic ve

ISSN:1422-6405    

DOI:10.1159/000144778

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Homochronous homografts of prospective cardiac area labeled with 3H thymidine have been carried out in chicken embryos at stages 5 and 6 of Hamburger and Hamilton. It has been observed how a heart tube or a vesicle, sometimes contractile, is developed by the graft. This vesicle, which is partly joined or not joined, to the receptor’s heart, is always in close dependence on the pharynx normogenesi

ISSN:1422-6405    

DOI:10.1159/000144779

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

The inferior alveolar nerve was cut or the vessels entering the mandibular canal were damaged in 39 guinea pigs at 10 days of age. Possible changes in the incisors were recorded during a 100-day observation period whereafter the animals were killed and the skulls freed of soft tissues; at this time, 35 skulls were found suitable for further examination. The changes in the mandibular incisors on the operated side became observable 30–40 days post-operatively as discolourization, a ‘trauma line’ around the tooth, narrowing of the tooth or total loss of it’s visible part. In the guinea pigs with the nerve cut (group A), such signs of maldevelopment were seen in 5 out of 19 animals, whereas the corresponding figure for the animals with the damaged vessels (group B) was 14/16. All incisors in group A and 13 out of 14 in group B recovered from the state of maldevelopment; one animal in group B showed complete loss of the incisor. The molar region was examined only from the cleaned skulls. In group A, the first molar was deformed in two animals; in group B, seven animals displayed either maldevelopment of the first molar or the first and second molar or complete loss of the first molar. No malformation of the third molar was observed. With two exceptions, the deformation or loss of molars occurred in combination with incisor maldevelopment. The malformations were considered to result from a disturbed blood supply. In group A, the dental changes may perhaps be ascribed to a short-term interference with the blood supply during the operation. The variable results in group B seem to imply that the mandibular teeth receive at least part of their blood supply from vessels besides those entering the mandibular canal. The innervation appears to have a subordinate role in the restoring of the morphology of continuously eruptin

ISSN:1422-6405    

DOI:10.1159/000144780

出版商:S. Karger AG    

年代:1977

数据来源: Karger

摘要:

Development of the proventricular glands was studied in chick embryos, 7–19 days of incubation. Morphologic evidence is presented to confirm the position of these glands in the tunica mucos

ISSN:1422-6405    

DOI:10.1159/000144781

出版商:S. Karger AG    

年代:1977

数据来源: Karger