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C Flügel

Publications and source records attributed to C Flügel.

16 recordsLinked to original sources
PubMed1992

Regional differences in the distribution of cytoskeletal filaments in the human and bovine ciliary epithelium.

The distribution of the cytoskeletal elements cytokeratin 18, vimentin, desmin, glial fibrillary acid protein (GFAP), and actin was investigated in different portions of the ciliary body of human and bovine eyes. Regional differences were found only for vimentin and cytokeratin. In both species, cytokeratin staining was more intense in the pigmented (PE) than in the nonpigmented epithelial (NPE) cells. In contrast, immunostaining for vimentin was more intense in the NPE than in the PE. The most intense immunoreactivity for cytokeratin 18 in the PE and for vimentin in the NPE was observed in the posterior pars plana and the crests of the pars plicata. In the remaining portions of the ciliary body, staining was reduced or absent. Desmin and GFAP were not found in the ciliary epithelial cells, whereas actin filaments occurred in both cell layers in all regions.

Animals↗
PubMed1992

Contractile cells in the human scleral spur.

The scleral spur in 37 human (age 17-87 years) and six cynomolgus monkey eyes (2-4 years) was investigated. Serial meridional and tangential sections were studied with ultrastructural and immunocytochemical methods. The bundles of the ciliary muscle do not enter the scleral spur, but their tendons, which consist of elastic fibres join the elastic fibres in the scleral spur. Within the scleral spur a population of circularly oriented and spindle-shaped cells is found. In contrast to the ciliary muscle cells, the scleral spur cells form no bundles, but are loosely aggregated. They have long cytoplasmic processes and are connected to each other by adherens-type and gap junctions. They stain intensely for alpha-smooth muscle actin, myosin and vimentin. In contrast to the ciliary muscle cells, they do not stain for desmin. Ultrastructurally, the scleral spur cells contain abundant thin (actin) filaments, but do not otherwise show the typical ultrastructural features of ciliary muscle cells. The scleral spur cells do not express a complete basal lamina. They form individual tendinous connections with the elastic fibres in the scleral spur, which are continuous with the elastic fibres of the trabecular meshwork. The scleral spur cells are in close contact with nerve terminals containing small agranular (30-60 nm) and large granular (65-110 nm) vesicles but also with terminals containing small granular (30-60 nm) vesicles which are regarded as typical for adrenergic terminals. We conclude that the scleral spur cells are contractile myofibroblasts. Their contraction might influence the rate of the aqueous outflow.

Adolescent↗
PubMed1992

Distinctive distribution of HLA class II presenting and bone marrow derived cells in the anterior segment of human eyes.

Cells of bone marrow origin that normally occupy the stroma of the murine iris and ciliary body have been implicated in the immune phenomenon, anterior chamber associated immune deviation (ACAID). Following injection of antigen into the anterior chamber, cells of this type deliver an ACAID inducing signal into the systemic circulation, presumably through the outflow tract. In an effort to identify such cells in man, anterior chambers of 34 human donor eyes of different age groups were stained immunocytochemically with monoclonal antibodies directed at HLA class II molecules, CD 45 (a molecular marker of bone marrow-derived cells) and macrophage-associated membrane molecules (CD 68, CD 14). Within the outflow tissue, the cells of the filtering trabecular meshwork stained with none of those reagents. However, infrequent single, dispersed, dendritic cells were positively stained in the intertrabecular spaces. More numerous labelled cells were found in the anterior- and posterior-most portions of the non-filtering part of the trabecular meshwork. These cells were continuous with stained cells adjacent to the outer wall of Schlemm's canal and to the collector channels. Numerous labelled cells were seen in the vicinity of the intra- and episcleral vessels, the ciliary meshwork, the stroma of the ciliary muscle and epithelial processes, and the iris stroma. With advancing age, increasing numbers of CD 45+, HLA class II expressing cells appeared to accumulate in the so-called uveoscleral pathway. These results indicate that bone marrow-derived cells with the potential to function of ACAID induction reside within human eyes, and that cells of this type are located not only in the stroma of iris and ciliary body, but within the non-filtering portions of the trabecular meshwork and the uveoscleral pathway. The appearance of rare CD 45+ cells "in transit" in the filtering trabecular meshwork is compatible with the view that cells carrying ACAID-inducing signals to the systemic immune apparatus escape from the eye by this route.

Adult↗
PubMed1991

The craniofacial proportions and laryngeal position in monkeys and man of different ages (a morphometric study based on CT-scans and radiographs).

Using CT-scans and radiographs, sagittal planes through the head and neck of men and monkeys at different ages were analyzed morphometrically for their craniofacial proportions and laryngeal position. In monkeys, a continuous prognathic growth of the splanchnocranium was found within the first 3 years. The neurocranial growth, however, was markedly reduced. The larynx of monkeys showed only a slight descensus with age. In contrast to this, the growth of the splanchnocranium in man did not change the craniofacial proportions significantly. The larynx, however, descended markedly within the first two years of life. In adults, the final position of the larynx was nearly 3 vertebral bodies further caudally than in the newborn. The differences in the postnatal position of the larynx, which is essential for the development of speech, are explained by differences in the growth pattern of human and monkey skulls.

Adolescent↗
PubMed1991

Different cell populations in bovine trabecular meshwork: an ultrastructural and immunocytochemical study.

Bovine outflow tissue differs markedly from that of humans. Tissue culture studies on the cells of this region are often compared with those of primate trabecular meshwork cells. A thorough cytological and immunocytochemical characterization of the cells of the bovine chamber angle is lacking. We have therefore investigated the cells of the pectinate ligament, the reticular meshwork, the region adjacent to the aqueous plexus, the connective tissue region between reticular meshwork and ciliary muscle and the ciliary muscle itself, ultrastructurally and immunocytochemically with staining for the cytoskeletal proteins vimentin and desmin, for alpha-smooth muscle-actin and rough endoplasmic reticulum (rER). In the pectinate ligament and in the region adjacent to the aqueous plexus, the cells were found to have especially abundant rER and glycogen in their cytoplasm. Vimentin was abundant in the reticular meshwork as positive staining was seen both in frozen and paraffin sections. Alpha-smooth muscle-actin could be found in the region connecting ciliary muscle and reticular meshwork as well as in a small area adjacent to the posterior capillary loops of the aqueous plexus. Ultrastructurally, these cells resembled myofibroblasts. The ciliary muscle cells stained both for vimentin and for alpha-smooth muscle actin.

Actins↗
PubMed1991

Electrical and morphological evidence for heterogeneous populations of cultured bovine trabecular meshwork cells.

Although trabecular meshwork cells are presumed to play an important role in determining ocular aqueous outflow resistance, little is known about their membrane transport characteristics. As in vivo access by microelectrodes is difficult, we used cell culture techniques to facilitate membrane voltage recording from cultured bovine trabecular meshwork cells. Phase-contrast microscopy revealed the presence of epithelial-like and spindle-shaped cell types. The mean membrane voltage for epithelial cells was -49.7 +/- 0.8 mV (S.E.M., n = 143) and for spindle cells was -70.9 +/- 1.9 mV (S.E.M., n = 48). These cells possess an electrogenic Na+/K(+)-ATPase and a K+ conductance. K transference numbers (tk) for [K+] from 5 to 80 mM were 0.50 for epithelial cells and 0.71 for spindle cells. The epithelial cells lack the electrogenic Na+/HCO3-symport, thereby enabling their differentiation from corneal endothelial cells and confirming previous reports of differences between these cell types. A proportion of spindle cells demonstrated spontaneous and induced fluctuations of membrane voltage. One millimolar Ba2+ (n = 9) induced an immediate depolarization of membrane voltage, with the onset of 'overshooting' action potentials, which were dependent on extracellular Ca2+ and Na+ but were not blocked by tetrodotoxin, 10(-6) M. Spindle cells showed parallel alignment of intracellular smooth muscle specific alpha-isoactin filaments, whereas epithelial cells showed specks of non-fibrous staining. Electron microscopy revealed that epithelial cells had the characteristics of metabolically active cells, with few intermediate filaments (10-12 nm) and microfilaments (6-7 nm) and short cytoplasmic processes. Spindle cells had long cytoplasmic processes and abundant intermediate- and microfilaments. These data provide further evidence for multiple bovine trabecular cell types. The smooth muscle-like spindle cell may represent the previously proposed contractile element of the angle and its action could conceivably alter ocular outflow resistance.

Actins↗
PubMed1991

Cell cultures of human ciliary muscle: growth, ultrastructural and immunocytochemical characteristics.

Primary ciliary muscle cell cultures derived from human donors (16-91 years) were established and characterized by comparing them with ciliary muscle in tissue sections using immunocytochemical and ultrastructural methods. Monoclonal antibodies against desmin, vimentin, alpha-actinin, smooth muscle (sm) specific alpha-actin and von Willebrand factor were used. In tissue sections of the ciliary body, ciliary muscle cells, vascular muscle cells, pericytes, endothelial cells and fibroblasts stain for vimentin. Both types of muscle cells and the pericytes stain for alpha-sm-actin, but only ciliary muscle cells stain for desmin. For tissue cultures, explants of the meridional and partly the reticular portion of the ciliary muscle were dissected and grown directly or after digestion of the explant with collagenase. Ten primary cell cultures with a typical hill-and-valley growth pattern similar to smooth muscle cells and two with a growth pattern similar to fibroblasts were established. All cultures could be subcultured up to the fifth passage. In fibroblast-like cultures 5-10% of the cells stained for alpha-sm-actin. Staining for desmin was not observed. In smooth muscle-like cultures, all cells stained positive for alpha-sm-actin. Desmin staining was not seen in growing non-confluent smooth muscle-like cultures. In confluent cultures, about 10% of the cells stained positive for desmin, preferentially in areas where the cells had formed hills. No culture stained for von Willebrand factor. Staining for alpha-actinin in smooth muscle-like cultures showed that the dense bands of the myofilaments were arranged in register, similar to the typical ciliary muscle cell morphology seen in tissue sections. Ultrastructurally, the smooth muscle-like cultures showed the typical morphology of cultured smooth muscle cells. We conclude that the smooth muscle-like cultures consist of ciliary muscle cells.

Actinin↗
PubMed1991

Histochemical demonstration of carbonic anhydrase in gills and opercular epithelium of seawater- and freshwater-adapted killyfish (Fundulus heteroclitus).

Gills and operculum of seawater- and freshwater-adapted killyfish (Fundulus heteroclitus) were stained histochemically for carbonic anhydrase (CA). In the seawater-acclimatized specimens, CA was found predominantly in the chloride cells which were considerably larger than in the freshwater-adapted ones. Within these cells, the reaction products were concentrated in the apical parts of the cytoplasm. In contrast, chloride cells of freshwater-adapted fish were not, or only faintly, stained both in gills and opercular epithelium. Reaction products for CA were seen additionally in the cytoplasm of the outer respiratory cells lining the lamellae of gills both in seawater- and freshwater-adapted fish.

Adaptation, Biological↗
PubMed1990

Histochemical differences within the ciliary muscle and its function in accommodation.

During accommodation, the ciliary muscle is known to move forward-inward. This movement depends on the stiffness of the ciliary muscle connections with the scleral spur. These connections are mediated by the tips of the meridional muscle. If the tips are weakened by pharmacological or surgical means, accommodation suffers. For normal accommodation, it is therefore necessary that the tips stiffen before the contraction of the main part of the muscle. We have therefore looked at the primate eye for enzymatic and ultrastructural differences between the tips and the bulk of the muscle viz, the reticular and circular portion. Myosin ATPase was stained after either alkaline or acid preincubation. Lactate dehydrogenase (LDH), succinic dehydrogenase (SDH), NADH-tetrazoliumreductase (TR) and lipids were stained using conventional methods. The results of the enzyme staining were a modest difference between the meridional tips and the bulk. The tips stained stronger for ATPase following both preincubation methods, and for LDH, whereas the bulk cells stained stronger for SDH, NADH-TR and lipids. The tips contained fewer mitochondria and more myofibrils. In all these respects, the tips of the meridional muscle resemble the fast fibers of striated muscle.

Accommodation, Ocular↗
PubMed1990

[Regional differences in the ciliary body of cattle. An electron microscopy and histochemical study].

The bovine ciliary body was investigated by scanning and transmission electron microscopy. The number of cell organelles (mitochondria, rough endoplasmatic reticulum and Golgi complexes) of the nonpigmented (UPE) and the pigmented (PE) epithelium were quantitatively evaluated. Histochemically the activity of carbonic anhydrase (CA) and Na+/K(+)-ATPase was localized within the UPE and PE. As a result of this study, the bovine ciliary body was found to be organized similar to the human and primate ciliary body and can be divided into 4 zones: (1) transition zone between the iris and ciliary body; (2) prelenticular portion of the pars plicata; (3) postlenticular portion of the pars plicata; (4) pars plana. In zone 2 the UPE and PE are filled by numerous mitochondria and show extensive infoldings of the basal cell membranes, which react positively for CA and Na+/K(+)-ATPase, indicating that these cells are involved in the secretion of aequous humor. The transition zone is covered by extremely flat UPE cells and might influence the composition of the aqueous humor by reabsorption rather than secretion. In the postlenticular pars plicata, the number of mitochondria, membrane infoldings and enzyme activity decreases, while the number of rER and Golgi complexes, which are necessary for the synthesis of proteins and proteoglycans, increases. In the pars plana, the UPE is filled completely with filaments pointing to the mechanical strain caused by insertion of the zonular fibers.

Animals↗
PubMed1990

[Structural differences in the structure of the ciliary muscles in eyes of primates. A histochemical and morphological study].

The ciliary muscle of the primate eye was stained histochemically with enzymes used to differentiate fiber types in the skeletal muscle. Differences between the outer meridional section and the rest of the muscle were found with all enzymes. Staining for myosin-ATPase with acid and alkaline preincubation, as well as for lactate dehydrogenase (LDH), resulted in a stronger reaction in the meridional section, while the reticular and circular portions showed minor activities. In contrast, succinate dehydrogenase (SDH) revealed a stronger activity in the reticular and circular muscle cells. Ultrastructurally, the meridional muscle cells contained fewer mitochondria, but more myofibrils in the cytoplasm, while circular and reticular muscle cells showed just the opposite. Therefore, the cells of the meridional ciliary muscle section resemble in some respects the rapid type-II skeletal muscle fibers, and the circular und reticular muscle cells are comparable to the slow type-I fibers of the skeletal muscle.

Animals↗
PubMed1989

Mechanically stripped pigmented and non-pigmented epithelium of the shark ciliary body: morphology and transepithelial electrical properties.

Sections of intact ciliary epithelium and mechanically stripped non-pigmented (NPE) and pigmented (PE) cell layers of adult sharks (Squalus acanthias) were mounted in Ussing-type chambers (area 0.1 cm2). Addition of 10(-5) M forskolin to the aqueous side of intact epithelium significantly increased short-circuit current (Isc) within 15 min and a maximum of approx. 30 microA cm-2 was reached after 45-60 min. Transepithelial potential difference (V) increased from -0.8 mV (aqueous side negative as compared with blood/stromal side) to -1.5 mV, whereas resistance (R) was unchanged (50 omega cm2). Forskolin was without effect when applied to the blood side. In stripped PE preparations (R 15 omega cm2), 10(-5) M forskolin applied to the apical side induced a qualitatively similar change of Isc and V compared with the intact tissue. The forskolin-induced effects were fully reversed by 10(-4) M bumetanide and were not dependent on pretreatment of the tissue with 10(-3) M BaCl2. In stripped NPE preparations resistance was usually less than 10 omega cm2 and was not stable. This is consistent with the morphologic observation that although tight junctions were still demonstrable in stripped NPE cells, the apical membranes were damaged. In preparations taken for light and electron microscopy the stripped PE layer revealed intact epithelial cells. In particular, the basal thirds of the stripped PE cells were in very close contact with each other. These attachment zones may have the appearance of tight junctions. Thus the PE cells of the shark ciliary epithelium can be successfully isolated for transepithelial transport studies. The adenylate cyclase system is present in PE cells, and transepithelial transport of chloride may be regulated by intracellular cAMP.

Animals↗
PubMed1989

Regional differences in the morphology and enzyme distribution of the spiny dogfish (Squalus acanthias) ciliary epithelium.

The ciliary epithelium of spiny dogfish eyes has previously been used for studies of epithelial electrolyte transport and the results are found to be comparable to those obtained in mammals. In this study we report the ultrastructure and enzyme histochemistry of the ciliary epithelium of spiny dogfish in comparison with that of mammals. In contrast to the mammals, the lens in spiny dogfish is connected to the anterior and middle part of the ciliary epithelium by a broad zonula-like suspensory ligament and by a short ligament to the ventral papilla, while the posterior region is mainly free of zonula-like fibers. The non-pigmented epithelium (NPE) of the posterior region shows numerous membrane infoldings, interdigitations and many mitochondria in the cytoplasm as well as histochemical staining for Na+ K(+)-ATPase and carbonic anhydrase (CA). These findings are similar to those seen in the anterior pars plicata of mammals which is mainly involved in aqueous secretion. In the anterior and middle part, the NPE cells have only a few membrane infoldings and few mitochondria in the cytoplasm, but abundant surfaces of rough endoplasmic reticulum, numerous ribosomes and Golgi material, indicating protein synthesis. Histochemically the cells stain for Na+, K(+)-ATPase but not for CA. These findings are comparable to the pars plana in mammals. In contrast to mammals, where the pigmented epithelium (PE) shows nearly no staining for Na+, K(+)-ATPase but an intensive one for CA, the PE cells of spiny dogfish are heavily stained for Na+, K(+)-ATPase in all regions of the eye, but show nearly no staining for CA.

Animals↗
PubMed1988

Presence and distribution of Na+/K+-ATPase in the ciliary epithelium of the rabbit.

Regional differences in the localization of Na+/K+-ATPase in the ciliary epithelium of albino rabbits were studied histochemically using the method of Chayen et al. and ultra-histochemically using a cerium-based method. In addition, the incubation time necessary to achieve first signs of staining was investigated as an indication of Na+/K+-ATPase activity. In the entire pars plicata: prelenticular, postlenticular, as well as tips and valleys, staining was seen in the lateral infoldings of the non pigmented epithelium (NPE) after short incubation periods. Somewhat later, the apical cell membranes also stained. The ultrastructure of these cells, together with the staining pattern, point towards a functional significance of the NPE in active fluid secretion. The pigmented epithelium (PE) did not stain. In the iridial processes and in the area of the ciliary ridges staining first appeared in the apical cell membranes of the NPE, which form the typical ciliary channels. The basolateral infoldings of the NPE also stained, whilst the PE remained unstained. The difference in morphology and staining between pars plicata and iridial processes could indicate a difference in function, e.g. reabsorption of freshly secreted aqueous humour. In the pars plana, only the basolateral infoldings of the PE stained. A functional significance of this area in connection with the blood retina barrier is discussed.

Animals↗
PubMed1988

Histochemical demonstration of carbonic anhydrase and Na+/K+-ATPase in the pecten oculi of the fowl.

The distribution of carbonic anhydrase (CA) and Na+/K+-ATPase was studied histochemically in the pecten of the fowl by light and electron microscopy. No Na+/K+-ATPase activity was seen by the method used here. CA staining was seen in the membranes of the apical and basal microvilli of the endothelial cells, while the cytoplasm took no stain. There were no staining differences between the capillaries of the different regions of the pecten. Only the capillaries of the bridge showed no microvilli and no staining. Neither did arterioles and venules which lacked microvilli stain. The functional significance of the association of CA activity and microvilli is not clear.

Animals↗