摘要:

The morphologic alterations of 7 human tumors of different origin and various histologic types, heterotransplanted to athymic nude mice, were investigated in the present study. Constant patterns of histologic and ultra-structural changes were observed in all 7 tumors. Following the initial dying of most inoculated tumor cells, host-supplied inflammatory cells invaded the xenografts and phagocytosed necrotic tumor cells. Fibroblasts which vivaciously produced collagenous material invaded the xenografts and built up solid strands of connective tissue which tightly contacted surviving tumor cells. These strands were used as guide-rails for ingrowing blood vessels. Immediately after their immigration, the first mitoses of tumor cells occurred in close proximity to capillary-conducting strands of connective tissue resulting in a revival of tumor cell proliferation near to the fibrous cords and a spreading of newly formed tumor cells along the strands of connective tissue. These results point to the host-supplied connective tissue as playing an important role for tumor proliferation and local tumor expansion.

ISSN:1422-6405    

DOI:10.1159/000146771

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The morphology of the retinal pigment epithelium (RPE), Bruch’s membrane (complexus basalis), choriocapillaris and tapetum lucidum has been studied in the eye of the ranch mink (Mustela vison) by light and electron microscopy. The RPE is composed of a single layer of cells joined laterally by apically located junctional complexes. Basally (sclerally) these cells display numerous infoldings whereas apically (vitreally) two types of processes are associated with rod and cone outer segments. Smooth endoplasmic reticulum and mitochondria are abundant in these cells whereas rough endoplasmic reticulum and polysomes, although present, are not plentiful. An occasional wandering phagocyte is noted at the RPE-photoreceptor interface. In the posterosuperior part of the fundus, a degenerative tapetum lucidum is present. The presence of only a few layers of tapetal cells containing but little reflective material and the haphazard arrangement of this material makes it very unlikely that this area functions as an effective tapetum lucidum. The RPE over the aberrant tapetum, however, shows the morphology that is seen when a functioning tapetum ceilulosum is present, namely the absence of melanosomes and an indented choriocapillaris. Bruch’s membrane in non-tapetal areas is pentalaminate but, over the tapetum and where it is associated with capillary profiles, it is reduced to a single, thickened basal lamina.The choriocapillary endothelium is highly fenestrated and in non-tapetal areas these capillaries are not indented into the epithelial la

ISSN:1422-6405    

DOI:10.1159/000146772

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The exorbital lacrimal glands (ELG) of rats were examined for both sexes to determine what degree of harderianization occurred as a function of age and after castration, and to investigate its time course and origin in ELG. Light microscopically, very small Harderian foci were seen in the ELG of both sexes at 3 weeks of age. As the male rats became older, the relative volume of the Harderian gland (HG) cells in the ELG increased. At age 6 months, the value was 1.25 ± 0.31% in males and 0.13 + 0.05% in females (p < 0.05). After castration, a significant decrease (0.21 ± 0.01% p < 0.05) was observed in that of male ELG. In contrast, in female ELG, HG cells were inconspicuous and the relative volume of those did not vary during this experimental period or after castration. It appeared that the HG cells had developed from undifferentiated basal cells of the acini and the intercalated ducts in the ELG at age 2–6 months. Then, at age 22 months, they also probably developed from those of the excretory ducts of the

ISSN:1422-6405    

DOI:10.1159/000146773

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

This paper presents a structural and morphometric study of the basement membrane underlying the parietal epithelium of cysts developed in the rabbit kidney after a single postnatal injection of methylprednisolone acetate. This epithelium consists of podocyte-like cells named parietal podocytes. Our results show that the parietal podocytes synthesize their own basement membrane in vivo. However, the different laminae of this membrane present differences in structure and thickness when compared to the analogous layers of both the normal glomerular and parietal basement membranes. Differences between the different zones of the parietal podocytic basement membrane are also observed, depending upon the structure that surrounds the cyst (capillaries, interstitial cells or loose connective tissue). A lamina lucida, analogous to the lamina lucida interna of the glomerular basement membrane, is formed only in segments of the parietal podocytic basement membrane in close contact with endothelial or interstitial cells. The thickness of the lamina lucida externa of the parietal podocytic basement membrane appears regulated by the presence of interstitial cells and capillaries. In the zones in contact with capillaries, the lamina densa of the parietal prodocytic basement membrane appears thinner than in other segments. This fact together with structural observations suggests that the formation of a single basement membrane, interposed between the parietal podocytes and the endothelium, does not take place by fusion of the two basement membranes but by previous removal of the capillary basement membrane. In areas where the parietal podocytic basement membrane is in contact with loose connective tissue, a lamina fibroreticularis is observed. All these data indicate that the formation of the basement membrane by the parietal podocytes is influenced by nonpodocytic cells. Around the glomerular cysts, a tardy formation of capillaries is observed. Parietal podoytes can be hypothesized to synthesize an angiogenic factor that may be implicated in the process of angiogenesis.

ISSN:1422-6405    

DOI:10.1159/000146774

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The effect of lidocaine-HCl on muscle spindles in the masseter muscle of developing mice was investigated. Repeated injections of mice with anesthetic in the short term decreased the diameters of primary endings, intrafusal muscle fibers and outer capsules in the equatorial regions of muscle spindles, and caused a drop in the succinic dehydrogenase activity in intrafusal muscle fibers of the muscle spindles. In addition, the diameters did not recover to the control value even after about 10 weeks following cessation of anesthetic treatment. Thus, the present results suggest that repeated use of lidocaine-HCl in developing animals may cause dysfunction of the skeletal muscles.

ISSN:1422-6405    

DOI:10.1159/000146775

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The present study deals with the detailed distribution of acid phosphatase (AcP) and simple esterase (SE) in different layers of the neocortex and hippocampal formation of the mouse brain. The neurons, in general, had moderate to intense enzyme activity for AcP and mild to moderate activity for SE. The AcP activity dominated in the neuronal population as compared to the neuropil; the neuropil stained mildly for SE.The large pyramidal cells in the neocortex and cornu ammonis, and the granular cell layer of the gyrus dentatus, demonstrated strong enzyme activity both in AcP and SE preparations. The role of AcP and SE has been discussed in relation to various structures of the neocortex and hippocampal formation.

ISSN:1422-6405    

DOI:10.1159/000146776

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

To investigate the cytodifferentiation and degeneration of odontoclasts in physiologic root resorption, we studied deciduous incisors undergoing resorption in 6-month-old kittens by electron microscopy of ultrathin sections. The endogenous peroxidase activity within the cells was also examined by incubating the tissue slices in diaminobenzidine-H202 medium. The resorbing tissues consisting of multinucleated giant cells macrophages granular leukocytes fibroblasts and many blood vessels were observed at the resorbing surface of the root dentine. Macrophages and granular leukocytes exhibited endogenous peroxidase activity, but mononuclear and multinucleated preodontoclasts and multinucleated odontoclasts did not. These preodontoclasts contained abundant mitochondria, a moderate amount of rough endoplasmic reticulum, stacks of Golgi membranes, lysosomes and numerous polyribosomes scattered throughout the cytoplasm. Many cellular processes extended from their cell surfaces by which the preodontoclasts appeared to fuse to one another during their multinucleation. Concomitant with the multinucleation process, the preodontoclasts developed numerous pale vacuoles throughout the cytoplasm. These vacuoles seemed to arise from some smooth endoplasmic reticula, perhaps representing Golgi-endoplasmic reticulum-lysosome, and the Golgi saccules. However, the preodontoclasts did not yet form a ruffled border and clear zones. When these preodontoclasts came into direct contact with resorbing dentine surfaces, they began to form the clear zones against dentine surfaces. Characteristically, numer--ous pale vacuoles were accumulated in the cytoplasm adjacent to the clear zone then they penetrated into the cytoplasm of the clear zone, and with this, ruffles of the plasma membranes appeared. Through a further movement of more pale vacuoles towards the ruffled plasma membranes the odontoclasts developed typical ruffled borders against the resorbing dentine surfaces. At this differential phase, little pale vacuoles appeared in the Golgi area, but the cisterns of the Golgi apparatus themselves reached their greatest extent during cellular differentiation. Fully differentiated odontoclasts frequently extended long broad cellular processes into the dentinal tubules exposed to the resorption lacunae. Although some odontoclastic processes penetrating the dentinal tubules contained vacuoles and lysosomal structures, most processes lacked any cytoplasmic organelles, and their cytoplasm resembled that of the clear zone. But these processes never exhibited ruffled-border-like structures. When the odontoclasts terminated their resorptive function, the ruffled borders lost their structural complexity, and excess plasma membranes derived from the ruffled borders were withdrawn within the cytoplasm as pale vacuoles. Finally, the odontoclast cytoplasm was occupied by numerous pale irregularly shaped vacuoles and autophagosomes containing cellular debris. These degenerated odontoclasts frequently fused with neutrophils. These findings are thought to indicate the life cycle of odontoclasts in the physiologic root resorption of deciduous teeth.

ISSN:1422-6405    

DOI:10.1159/000146777

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Cross-sections of normal digastric, temporalis and masseter muscles from 7- and 30-week-old mice were studied for centrally positioned nuclei. Such nuclei were inhomogeneously distributed throughout each muscle and varied markedly between specimens. The incidence of centrally positioned nuclei in the digastric muscle (mean ± SD: 0.029 ± 0.015, n = 25) was significantly higher (p < 0.001) than that in the temporalis (mean ± SD: 0.011 ± 0.010, n = 25) and masseter muscles (mean ± SD: 0.005 ± 0.007, n = 9), but did not differ between the two latter muscles (p = 0.41). Furthermore, the frequency in a given muscle was apparently age-independent. A connection between fiber type and centrally positioned nuclei is sugg

ISSN:1422-6405    

DOI:10.1159/000146778

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The sublingual glands of 2 male and 2 female adult ferrets were examined using electron microscopy. The secretory end piece consisted of mucous tubules, serous and mixed acini. The mucous cells showed two different types of granules. The serous cells contained electron-dense secretory granules. The duct system entirely comprised excretory ducts.

ISSN:1422-6405    

DOI:10.1159/000146779

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The fine structure of the parathyroid glands of propranolol-treated hamsters subjected to 5 × gravity environment was studied. In the parathyroid glands of the propranolol-treated hamsters exposed to hypergravity environment, the volume density occupied by the Golgi complexes and cisternae of the granular endoplasmic reticulum was increased as compared to that of propranolol-treated hamsters and was decreased as compared to that of hamsters exposed to a hypergravity environment but was almost similar to that of control hamsters. In addition, many chief cells contained rich free ribosomes, abundant mitochondria and some secretory granules located in the peripheral cytoplasm. These findings suggest that the parathyroid gland which may be suppressed by treatment of propranolol and stimulated in response to a hypergravity environment indicates the secretory activity of the control parathyroid gland

ISSN:1422-6405    

DOI:10.1159/000146780

出版商:S. Karger AG    

年代:1989

数据来源: Karger