摘要:

AbstractTensile breaking load, strength, strain, modulus of elasticity and density plus the histological structure at the fracture site, were determined for 207 standardized specimens of cortical bone from the embalmed femur, tibia, and fibula of 17 men from 36 to 75 years of age. The men were divided into a younger group (41.5 years old‐avg) and an older group (71 years old‐avg). Specimens from younger men had a greater average breaking load, strength, strain, modulus and density than those from older men. The percentage of spaces in the break area was greater in specimens from older men, but specimens from younger men had a slightly greater percentage of osteons, osteon fragments, and interstitial lamellae. The number of osteons/mm2and of osteon fragments/mm2was greater in specimens from older men but the average area/osteon and area/osteon fragment was greater in specimens from younger men. Thus, there are quantitative and qualitative differences in the histological structure of bone from younger and older men. Differences in the tensile properties of bone from younger and older men can be explained by histological differences in the b

ISSN:0003-276X    

DOI:10.1002/ar.1091850102

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

年代:1976

数据来源: WILEY

摘要:

AbstractYoung adult male rats were treated with daily injections of 10 mg of cyproterone acetate for periods up to 16 weeks. Samples of the ventral prostate and the seminal vesicle were studied with the light and electron microscopes. Alterations visible with the light microscope included decreases in cell size, cytoplasmic basophila, the size of the nucleolus, and the amount of luminal secretory material. Ultrastructural changes in the epithelium of both glands involved mainly the organelles that participate in the formation of secretions. Large declines were observed in the abundance of rough endoplasmic reticulum, size of the Golgi apparatus, and number of secretory vacuoles. Lipid droplets accumulated in the seminal vesicle epithelium, and lysosomes were numerous in both glands. Changes were first observed microscopically in the seminal vesicle after one week and in the prostate after two or three weeks. Maximal development of the alterations occurred after treatment for approximately eight weeks.

ISSN:0003-276X    

DOI:10.1002/ar.1091850103

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

年代:1976

数据来源: WILEY

摘要:

AbstractEstrogen treatment for one month in female rats caused some regression of somatotrophs, but induced an increase in the number of prolactin cells and caused these cells to hypertrophy. These stimulated prolactin cells showed extensive development of the granular endoplasmic reticulum which was often arranged in concentric whorls (Nebenkern). Most of the prolactin cells contained a small number of mature granules which were smaller in size than those of prolactin cells in control animals. These prolactin granules were round in sectioned profile and closely resembled the secretory granules of normal somatotrophs.At five and ten days after the suspension of estrogen treatment, many prolactin cells contained numerous secretory granules of various sizes ranging from 150–500 nm. Only occasional granules in these cells were as large as 750 nm, and only the largest of the granules exhibited the irregular shape which is characteristic of mature granules in normal prolactin cells. Fifteen days after the cessation of estrogen injection most prolactin cells exhibited numerous secondary lysosomes. At this time the mature secretory granules were similar in morphology to those of normal prolactin cells.From the fact that the somatotrophs appeared not to be stimulated by the estrogen treatment we find it difficult to accept the concept that somatotrophs cna undergo transformation into prolactin cell

ISSN:0003-276X    

DOI:10.1002/ar.1091850104

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe fluorescence histochemical method of Falck‐Hillarp ('62) demonstrates dense plexuses of catecholamine‐containing nerves in the piloarrector muscles of adult stump‐tailed macaques. When these muscle fibers are viewed under the electron microscope, most of the axon terminal profiles between them contain numerous dense‐cored vesicles (adrenergic); the rest of the terminals contain mainly agranular vesicles (cholinergic). Intradermal injections of 6‐hydroxydopamine (6‐OHDA, 1 and 5 mg) or 5‐hydroxydopamine (5‐OHDA, 10 mg) into the scalp caused the fluorescence from the nerve fibers in the muscles to completely disappear. The 6‐OHDA injections induced severe degenerative changes in the adrenergic terminals whereas the 5‐OHDA injections caused only the granules in the vesicles to increase in numbers. Thus, the piloarrector muscles of these macaques are innervated with both adrenergic and cholinergic terminals, but the former are more numer

ISSN:0003-276X    

DOI:10.1002/ar.1091850105

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe skin of the giraffe has the same general histological structure as that of other mammals, but there are notable features. The skin is heavily pigmented with the epidermis, pilary canals, and the outer cell layer of the apocrine duct richly melanized. Furthermore, melanotic dendritic cells are frequently found in the sebaceous glands, the entire length of the external root sheath, and the secretory tubules of the apocrine glands. The thick skin has a papillary dermis that extends to just beneath the secretory coils of the apocrine glands and bulbs of hair follicles and an equally thick reticular layer below these structures. The hair follicles do not grow in clusters, and with some regional variations, have associated sebaceous glands, apocrine glands, and arrectores pilorum muscles. Only the large hairs have a prominent medulla. In such specialized regions as the eyelids, nose, and lips, the apocrine glands are surrounded by cholinesterase‐reactive nerves but the glands on the general body surface are not. The only specialized nerve receptors are hair follicle end organs found on every hair of the eyelids, nose, and lips, but only rarely elsewher

ISSN:0003-276X    

DOI:10.1002/ar.1091850106

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe presence of microblebs arising from the lateral surfaces and tips of microvilli of intestinal epithelial cells of thirteen‐lined ground squirrels.Citellus tridecemlineatus, is reported. Microblebs measure ∼ 50 nm in diameter and are bounded by a unit membrane which is continuous with the unit plasma membrane of the microvilli. It is suggested that such microblebbing reflects the rapid turnover of microvillar contents, membrane and surface c

ISSN:0003-276X    

DOI:10.1002/ar.1091850107

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe nerves in and immediately under the epithelial layer of the trachea and primary bronchi of the cat are studied with the electron microscope. The axons are unmyelinated and contain microtubules and mitochondria. Epithelial axons are observed throughout the entire epithelial layer, but, are usually concentrated in the basal area immediately above the basal lamina. Most axons are near the basal cells; others are in the vicinity of granulated cells or occur in the intercellular spaces between other columnar cells. A few of the epithelial axons are large and crowded with axoplasmic mitochondria. The possibility that some epithelial axons may have sensory functions is discussed.

ISSN:0003-276X    

DOI:10.1002/ar.1091850108

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

年代:1976

数据来源: WILEY

摘要:

AbstractWhen skin from the upper lip of 12‐day embryonic mice was grown for ten days in organ culture with 5.7 μg retinol added per ml of biological medium, keratinization was suppressed and a ciliated and secretory epithelium was produced. Ultrastructural features of this epithelium are described. At this very early stage mouse epidermis is thus similar to chick epidermis in its ability to undergo radical metaplasia in response to vitamin

ISSN:0003-276X    

DOI:10.1002/ar.1091850109

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe kinetics of lymphoid cells within the epithelium of the small gut has been studied in various thymus‐deprived mice and in antigen‐deprived mice by the use of3H‐thymidine injections and radioautography. In thymusdeprived mice —including adult thymectomized, thymectomized and irradiated, neonatally thymectomized, and nude mice —and in germ‐free mice decreased numbers of intraepithelial lymphocytes (IL) were found. On the other hand, the radioautographic results indicated that the remaining IL populations included both newly formed and long‐lived lymphoid cells in the same percentages as found in sham‐operated controls and normal mice. It is concluded that although the presence of the thymus and the antigen content of the gut is of importance to the maintenance of the numbers of cells in the lymphoid populations of the intestinal wall, the basic kinetics of these cell populations are preserved i

ISSN:0003-276X    

DOI:10.1002/ar.1091850110

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

年代:1976

数据来源: WILEY

摘要:

AbstractNeurohistochemical techniques were used to confirm morphologically the distribution of adrenergic and cholinergic nerves to the splenic microvasculature. The results form the basis of this report.Using these methods, adrenergic innervation was observed only in the adventitia of arteries and arterioles. No cholinergic innervation was found in this site. No adrenergic or cholinergic innervation could be demonstrated to the channels of the red pulp, venules or veins. These data provided morphological evidence that in the murine spleen only splenic arteries and arterioles are innervated; and these have only an adrenergic innervation.

ISSN:0003-276X    

DOI:10.1002/ar.1091850111

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

年代:1976

数据来源: WILEY