摘要:

Immunohistochemical localizations of the intrinsic basal lamina (BL) components laminin-1 and type IV collagen, the adhesion molecules type VII collagen and laminin receptor (a6p, integrin), and the type IV collagenase (72 kDa, MMP2) were analyzed in carcinomas of the mouse skin which were chemically induced by benzo[a]pyrene with or without the addition of the promotor phorbol 12-myristate 13-acetate. Normal skin, dysplastic lesions, and invasive carcinomas were investigated by histological and immunohistochemical (immunofluorescence and APAAP) methods. A regular and continuous staining of laminin-1 and type IV collagen was present in the normal skin and in areas of slight and moderate dysplasia. Underneath highly dysplastic epithelium, the BL became thin, loosened and sometimes disrupted, and accumulations of globular BL material were found in the connective tissue underneath the BL. Type VII collagen retained a more linear, continuous and uniform distribution in the areas of progressed epithelial dysplasia. All invasive carcinomas were characterized by a BL which was disrupted by gaps of varying size but, again, showed a more uniform and less discontinuous distribution of the anchoring molecule type VII collagen. Expression of the integrin laminin receptor investigated increased quantitatively in dysplastic lesions and in areas of invasive carcinomas, showing a circular presence at the surface of most epithelial cells of the basal and spinous layers of the epidermis, whereas, in the normal skin, the laminin receptor was polarized to the basal and lateral cell membrane of basal epithelial cells in contact with the BL. These results suggest that the discontinuities occurring in the BL during carcinoma cell invasion are not caused by a local loss of the anchoring molecules type VII collagen and/or laminin receptor, though alterations in the pattern of expression of the laminin receptor document fundamental changes in the cellular organization occurring during malignant transformation. On the other hand, the presence of the type IV collagenase increased in epithelial dysplasias and invasive carcinomas. In many dysplastic lesions, it was deposited in a plaque-like and sometimes linear manner near the basement membrane (BM) region indicating that, in chemically induced carcinomas, this enzyme may be involved in the process of BM perforation during carcinoma cell invasion.

ISSN:1422-6405    

DOI:10.1159/000147784

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The distribution of transforming growth factor-alpha (TGFα), a member of the epidermal growth factor (EGF) family, was studied immunohistochemically in small intestinal tissues of suckling pigs which were 7, 14 and 21 days of age. TGFα immunostaining was similar in villous epithelium in all intestinal regions of all ages examined, and was diffuse throughout the epithelial cytoplasm and more prominent in the apical and brush-border regions of the cells. Cytoplasmic immunoreactive TGFα was also identified in crypt epithelial cells; the pattern and extent of immunostaining differed among intestinal regions and ages. In all cases, the relative number of TGFα-immunopositive crypt epithelial cells was fewer than the number of immunonegative cells within the compartment. In duodenal and jejunal segments, relative numbers of immunopositive crypt epithelial cells were greater in 14- and 21- than in 7-day-old pigs. In all 7-day-old pigs, a relatively greater number of immunopositive epithelial cells was present in the jejunal crypts than in the duodenal crypts. Intracellular TGFα immunostaining was present within Peyer’s patches of distal jejunum and ileum, and is a previously unreported finding. The presence of TGFα immunoreactive protein within small intestinal crypt epithelium has not been previously described in any species, and may be unique to suckling animals or, alternatively, the porcine species. These data suggest that TGFα may be an endogenous ligand for the EGF receptor in suckling porcine intestine. Increased expression of TGFα in suckling pigs during the period in which marked structural and functional changes occur within the small intestinal mucosa suggests a role for this growth factor in remodelling and maturation of the neonat

ISSN:1422-6405    

DOI:10.1159/000147785

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

During a search for resident subendothelial smooth muscle cells in pulmonary vessels of the rat we found that in expanded lungs the muscular pads in the veins, considered by some authors as sphincters, were hardly visible whereas in collapsed lungs they were very conspicuous. In a separate study intended to quantify the degree of collapse or expansion the left lung was examined in 5 rats with a collapsed and in 5 rats with an expanded lung: the expansion was produced by filling the airways by gravity with Methacarn fixative. The degree of expansion was determined by morphometry measuring the volume density of the tissue fraction of the pulmonary parenchyma in the microscopic sections: in the expanded lung the mean value was 8.5% (range 6.7–12.6%), in the collapsed lung 20.1% (range 18.7–22.3%), a highly significant difference (p < 0.000). Serial sections generally 60–100, 6-um-thick, were stained by PAS, Sirius red hematoxylin and Verhoeff s elastic stains. Immunohistochemical staining was done with monoclonal antibody against alpha smooth muscle cell actin and desmin. Graphic reconstructions of representative vessels were performed. It was shown that the muscular media of the veins was interrupted and that the muscular pads corresponded to the contracted smooth muscle cell segments alternating with the noncontracted segments devoid of muscle. In the expanded lungs muscular pads were flattened and often hardly detectable. This indicates that the structures considered as sphincters are postmortem contraction rings in collapsed

ISSN:1422-6405    

DOI:10.1159/000147786

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Histological, histochemical, and quantitative morphometric techniques were used to determine muscle fiber-type distributions and sizes in four intrinsic tongue muscles of Macaca fascicularis. Histologically, fiber interdigitation among muscles was striking with pronounced infiltration of endomysium into muscle fascicles. Endomysium and perimysium were most prominent anteriorly. Histochemically, with a sample of 20,106 fibers, type II fibers predominated (73.9%) over type I fibers (26.1 %) and 99% of type II fibers were categorized as IIA. The relative density of type I and type IIA fibers varied consistently within all muscles from anterior to posterior and to a lesser degree from superficial to deep. Although the tongue apex was composed almost exclusively of type IIA fibers, the proportion of type I to type IIA fibers increased posteriorly. Most posteriorly, type I and IIA fibers were in about equal proportions. These nonuniform fiber-type concentrations may suggest that different segments of individual primate intrinsic tongue muscles may be functionally independent, supporting recent models of tongue motor system biomechanics. For example, predominantly type IIA fibers in the anterior segments of a given muscle may underlie characteristic rapid tongue tip movements while slower movements of the posterior tongue are executed via separately activated type I fibers. Mean fiber diameters were quantified in one animal (n = 7,758). The distribution was unimodal (5.61–63.03 um) and overall type IIA fibers were larger than type I fibers. However, within all muscles studied, sizes of both fiber types were greater at posterior sites, further suggesting functional intramuscular segregatio

ISSN:1422-6405    

DOI:10.1159/000147787

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

A study of the number of muscles, the nerve branches innervating them and number and distribution of the motor points was carried out on the forearm of the monkey (Macaca fascicularis) and human. There were 8 flexor muscles and 11 extensor muscles in the human, while there were 7 flexors and 12 extensors in the monkey. The distribution of the branches of the median, ulnar and radial nerves were similar in both species. The number of motor points and their distribution in the flexor and extensor muscles also showed considerable similarity between the two species. The monkey is a suitable experimental animal model for the study of the clinical application of functional electrical stimulation of the paralyzed forearm and hand of patients with upper motor neuron lesions.

ISSN:1422-6405    

DOI:10.1159/000147788

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

With the use of postembedding electron-microscopic immunogold cytochemistry, the vesicular distribution of serotonin within serotonergic synaptic terminals in the mesencephalic trigeminal nucleus was determined in order to obtain further insight into the mechanisms and functional significance of serotonin release to these jaw muscle spindle afferent neurons. Immunogold labelling was restricted to the previously described type I and type II terminals. The distribution of immunogold particles over the synaptic terminals indicated that serotonin was stored in small round or pleomorphic (RSV) vesicles and in large granular dense-cored (DSV) vesicles. The amount of serotonin present in the DSV vesicles, which are generally considered to contain colocalized neuropeptides, showed a high degree of variation. These DSV vesicles were usually located at some distance from the synaptic area of the terminals suggesting that they represent a nondirectly releasable vesicle pool. The serotonergic RSV vesicles were, in general, irregularly distributed over the terminals. However, in about 19% of the analyzed labelled synaptic terminals serotonergic RSV vesicles were clustered together near their release site at the synaptic cleft. These synaptic terminals may represent highly active serotonergic synapses with a high release frequency and a high reuptake level, resulting in a dense concentration of vesicles containing a high amount of serotonin near the synaptic cleft.

ISSN:1422-6405    

DOI:10.1159/000147789

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Three adult Cebus apella and two Saimiri sciureus monkeys, as well as four adult rat brains were processed for glial fibrillary acid protein (GFAP) immunocytochemistry. Irregular patches with relatively abundant, long astrocytic processes were found in monkey but not in rat brains, along the cingulate, as well as orbital, medial and dorsolateral cortices of the frontal lobe, and in temporal lobe cortical areas. The observed long astrocytic processes alternated in an apparent irregular fashion with others with a predominantly clear background and scattered GFAP-immunoreactivity (IR) astrocytes or with a predominant GFAP-IR-dense fibrillary meshwork. They usually stemmed from lamina I or II and coursed through deep laminae. Entorhinal cortex in rat brains showed occasional astroglial processes somewhat longer than those commonly observed in other cortical regions, albeit significantly shorter than those observed in Ceboidea monkeys and not truly interlaminar. These observations indicate a clear morphological difference in astroglial organization between nonhuman primates and a rodent brain. They further show that ‘interlaminar astrocytes’ are distributed nonhomogeneously in the frontal cortex of New World monkeys. No interlaminar processes were observed in cortical areas of rat brains. Even though the physiological role of interlaminar astrocytes in a primate brain remains unknown, their significant departure from the morphology of classical, stellate astrocytes suggest that they may subserve different cortical requireme

ISSN:1422-6405    

DOI:10.1159/000147790

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

A hypothesis is proposed that unifies prostatic developmental biology and carcinogenesis. The foundation of this hypothesis is the reciprocal interaction of epithelium and mesenchyme during prostatic development followed thereafter by a reciprocal homeostatic interaction of epithelium and smooth muscle in adulthood. This smooth muscle-epithelial cell interaction is perturbed during prostatic carcinogenesis with adverse sequelae for both epithelium and smooth muscle. The following sequence of events is proposed to occur: (1) Under the influence of androgens, urogenital sinus mesenchyme (UGM) induces urogenital sinus epithelium to undergo prostatic ductal morphogenesis and differentiation. (2) As prostatic epithelium differentiates, it in turn signals the UGM to differentiate into smooth muscle cells that closely surround the epithelial ducts. Differentiation of prostatic smooth muscle requires both an inductive signal from epithelium and androgens. (3) Once formed, prostatic smooth muscle participates in reciprocal homeostatic interactions. We propose that prostatic smooth muscle under the influence of androgens signals to prostatic epithelium to maintain epithelial differentiation and to repress epithelial proliferation, while prostatic epithelium signals to prostatic smooth muscle to maintain smooth muscle differentiation. In adulthood, homeostasis is maintained through reciprocal interactions between smooth muscle and epithelial cells with minimal proliferation of either cell type. Prostatic carcinogenesis, which is initiated following genetic damage to prostatic epithelium, is surmised to involve a sequential disruption in these reciprocal homeostatic interactions with ensuing dedifferentiation of both the emerging prostatic carcinoma cells and smooth muscle. Thus, following genetic insult to prostatic epithelium the epithelium fails to signal appropriately to the smooth muscle, which then begins to dedifferentiate. As smooth muscle differentiation begins to deviate, signaling from prostatic smooth muscle to prostatic epithelium becomes anomalous resulting in progressive loss of control over epithelial differentiation and proliferation. During progression of prostatic carcinogenesis a vicious cycle is established in which both prostatic epithelium and smooth muscle dedifferentiate. This hypothesis is based on the ontogeny of prostatic smooth muscle differentiation during development and by the fact that the amount of smooth muscle progressively diminishes in human prostatic adenocarcinomas during progression from low- to high-grade cancers. Finally, in experimental tissue recombinants in which various normal or neoplastic prostatic epithelia were grown in combination with embryonic rat UGM, only normal (nonneoplastic) epithelia were capable of inducing differentiation of prostatic smooth muscle in UGM. Based on several lines of evidence, it is now apparent that smooth muscle-epithelial interactions are the operative cell-cell interaction in the postnatal prostate which plays a key role in regulating epithelial differentiation, proliferation and carcinogenesis.

ISSN:1422-6405    

DOI:10.1159/000147791

出版商:S. Karger AG    

年代:1996

数据来源: Karger