摘要:

The pattern of the arterial system has been studied in the hindlimbs of adult male and female mice in a hybrid strain. A technique was developed to inspect the distribution pattern after the vessels were injected with a blue polymer, the bone was stained with alizarin red S, and the soft tissue was cleared to transparency. Substantial variations were identified in the point of origin of 6 of 41 arterial branches; extra vessels and absence of vessels were uncommon. The types of arterial differences identified in normal adult mice were different from those identified in mice with absence of the tibia, which have absence of major arteries, including the popliteal and posterior tibial arteries.

ISSN:1422-6405    

DOI:10.1159/000146542

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The mast cell population has been studied during early decidualization of the mouse uterus. The number increases in early pregnancy until the attachment phase when a sharp depletion is noticed.This fall has been correlated with stimuli of maternal origin, but at the same time the presence of a blastocyst at the presumptive implantation sites seems to exert a significant effect on the depletion of mast cells. A relationship between the number of mast cells in the uterus and the physiological state of the organ has definitely been established [Harvey, 1964; Likar and Likar, 1964; Gibbons and Chang, 1972; Brandon and Evans, 1983]. The number of mast cells in the pregnant uterus is known to decrease around the time of implantation in the rat [Shelesnyak, 1960; De Feo, 1967; Brandon and Bibby, 1979]. Several workers believe that the mast cell population and histamine content decrease as a result of a rise in circulating estrogen [Westin, 1955; Gibbons and Chang, 1972; Spaziani, 1975]. In the present communication the possibility of a relationship between the decrease in mast cell population and the presence of a blastocyst, whose estrogenic role has been reported [Dickmann and Dey, 1973; Dickmann et al., 1975; Sengupta et al. 1977] in the uterine horn has been discussed.

ISSN:1422-6405    

DOI:10.1159/000146543

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Thymic involution is a slow physiological process that can be accelerated by some pathological or experimental conditions. In this work we kept male mice under low temperatures in order to observe whether or not thymic involution would be promoted. For this purpose, we carried out a histometrical analysis of the thymus and observed that there was a decrease in both cortical and medullary regions of the thymic lobules. These changes paralleled a loss in the absolute and relative weights of the thymus. It was concluded that low temperatures induce thymic involution even in nonhibernating animals.

ISSN:1422-6405    

DOI:10.1159/000146544

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The neuroectodermal cells of chick embryos have been analyzed during neurulation by stereological and morphometrical ultrastructural methods in an attempt to describe their cytometric evolution. A profound change of cellular form coefficient was observed which is related to the typical process of columnarization of these cells. At stages 7 and 8 the nucleus appeared round in shape probably due to a loss of pressure of the vitelline inclusions. In this sense the volume density of these inclusions falls during this period. There was also a significant increase of the nuclear surface density, the significance of which is discussed on the basis of the nucleo-cytoplasmic interchanges and the differentiation process. At the same time, an increase in the number of mitochondria was observed, which is related to the neural folding process. Simultaneously, the amount of rough endoplasmic reticulum increases, presumably related to the remarkable changes of the embryonic extracellular matrix.

ISSN:1422-6405    

DOI:10.1159/000146545

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Arteriovenous anastomoses (AVAs) participate in the regulation of blood flow. Although it has been speculated that AVAs in the dog’s tongue play a role in the regulation of the body temperature, no published work is available on the structural characteristics of AVAs in the dog’s tongue. The purpose of the present investigation was therefore to determine the frequency of AVAs and their structural characteristics by the fabrication of vascular corrosive resin casts and examination under a scanning electron microscope.This method permitted not only the visualization of the three-dimensional characteristics of AVAs, but also a clear differentiation between arterioles and venules. The total number of AVAs in the mucosal lamina propria of the dorsum of the left tongue half was 2,292. Several essential types such as S-shaped, hook-shaped, straight, bibranching and Y-shaped AVAs were observed, of which the S-shaped and similar types constituted the overwhelming majority; Y-shaped types have never been reported heretofore. This study also revealed that the locations where AVAs were most often distributed were, in descending order of frequency, the tip, the corpus and the root area of the tongue. This high frequency and strategic location of AVAs in the tongue strongly indicate that AVAs of the dog’s tongue participate in the thermal regul

ISSN:1422-6405    

DOI:10.1159/000146546

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

In vivo activation of platelets, produced by damaging an artery in the rat with ultrasound, was studied with the electron microscope. We performed both a three-dimensional reconstruction by thin serial sections and a morphometric study of the activation process. This is characterized by exocytosis of the content of granules, widening of tubules of the open canalicular system, and emission of pseudopodia. The three-dimensional reconstruction suggested that some extended pseudopodia adhere to the arterial intima, and confirmed former observations that a locomotor apparatus differentiates in platelets adhering to the arterial intima. We speculate that the contraction of some pseudopodia may pull the platelet body toward the arterial wall.The morphometric study revealed that during activation the volume of the open canalicular system volume increases and that of the dense granules decreases; all other compartments did not change.

ISSN:1422-6405    

DOI:10.1159/000146547

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The notochords of three normal, 35-day Mαcαcα mulαttα embryos were examined ultrastructurally. Notochordal cells had numerous polysomes and ribosomes, and some rough endoplasmic reticulum, mitochondria, Golgi complexes, coated vesicles, and secretory granules. A discontinuous basal lamina surrounded the notochord. Intercellular channels and the perinotochordal sheath contained fibrils. It was found that the ultrastructure of the rhesus monkey notochord at stage 17 resembles that of the chick and m

ISSN:1422-6405    

DOI:10.1159/000146548

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Bichat’s fat-pad was examined using dissections of newborns and adults, and histological sections of embryos and fetuses. A main part or body with six extensions (masseteric, superficial temporal, deep temporal, pterygomandibular, sphenopalatine and inferior orbital) can be recognize

ISSN:1422-6405    

DOI:10.1159/000146549

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Hyperostosis (lipping) due to costovertebral arthritis was found frequently (84.3%) impinging on the sympathetic trunks (ganglia and cord), rami communicantes and roots of the splanchnic nerves on both sides of the spine in more than 1,000 dissecting room cadavers examined and 34 cadavers of adult and elderly people specially dissected. As a result of the compression, the affected sympathetic structures were angulated, deflected from their course, enlarged and often infiltrated with connective tissue. The possible symptoms which may result from this kind of compression are discussed.

ISSN:1422-6405    

DOI:10.1159/000146550

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Chick embryo movements were picked up, by means of a vibration-recording technique, from the 5th day of incubation until the moment of hatching, and correlated with histological observations of the main joints. A close relationship could be demonstrated between the dates on which the first movements can be recorded and the commencement of joint formation.

ISSN:1422-6405    

DOI:10.1159/000146551

出版商:S. Karger AG    

年代:1988

数据来源: Karger