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Biomedical subjects

W Noske

Publications and source records attributed to W Noske.

17 recordsLinked to original sources
PubMed1992

[Multiple evanescent white dot syndrome].

A 38-year-old male patient experienced a unilateral visual acuity decrease to 20/60 and showed white dots at the level of the retinal pigment epithelial interface characteristic of multiple evanescent white dot-syndrome. Fluorescein angiography demonstrated early hyperfluorescent defects and some late staining. In spite of improvement of the visual acuity and the alterations of the fundus, an enlargement of the blind spot and some sharply demarcated depigmentations of the retinal pigment epithelium remain. This case shows, that already at the beginning of symptoms the characteristic white dots may be present. Enlargement of the blind spot and depigmentations of the retinal pigment epithelium may remain as defects after multiple evanescent white dot-syndrome.

Adult↗
PubMed1992

Human eye: visualization of perfluorodecalin with F-19 MR imaging.

Perfluorodecalin (PFD) was demonstrated in a human eye with fluorine-19 magnetic resonance (MR) imaging by employing a standard two-dimensional fast low-angle shot (FLASH) sequence. The presence and intraocular distribution of PFD were revealed despite the posterior eye segment being obscured by a narrow pupil, multiple small intraocular gas bubbles, and an intraocular hemorrhage. This examination can be performed with standard sequences on MR imaging systems equipped with a fluorine channel.

Cataract Extraction↗
PubMed1992

Endothelin-like immunoreactivity in the aqueous humour and in conditioned medium from cultured ciliary epithelial cells.

Endothelin-like immunoreactivity was detected in human (15.6 +/- 2.7 pg/ml) and bovine (11.1 +/- 0.98 pg/ml) aqueous humour of the eye. These concentrations are 2-3 times higher than the corresponding plasma levels. Cultured human nonpigmented ciliary epithelial cells released endothelin-like immunoreactivity with a maximum of 2.1 +/- 0.32 pg/(cm2* 48 h). The release was stimulated by fetal calf serum, thrombin, carbachol and phorbol ester and blocked by cycloheximide. Immunocytochemistry showed cytoplasmic staining of cultured human nonpigmented ciliary epithelial cells for endothelin-1. Endothelin-1 was shown to induce contractions in isolated human ciliary muscle by isometric force measurements. Endothelin in the aqueous humour may play a role in the regulation of intraocular pressure.

Animals↗
PubMed1989

Filipin-induced deformations in plasma membranes of cultured bovine corneal endothelial cells with incomplete belts of tight junctions.

Complete belts of intact tight junctions are thought to act as barriers to the movement of cholesterol in the plane of the plasma membrane. As cholesterol can be revealed by filipin-induced membrane deformations on freeze-fracture images, we studied the distribution of these deformation in cultured bovine corneal endothelial cells with incomplete belts of tight junctions. While the extent of filipin-induced deformations differed between individual cells, there is a homogeneous distribution of filipin-induced deformations on both sides of the incomplete junctional belt of endothelial cells. Our results suggest that cultured endothelial cells do not polarize cholesterol, possibly because of the incomplete tight-junctional barrier.

Animals↗
PubMed1988

Orthogonal arrays of particles in non-pigmented cells of rat ciliary epithelium: relation to distribution of filipin- and digitonin-induced alterations of the basolateral membrane.

It has been suggested that orthogonal arrays of particles may increase the rigidity of plasma membrane, as does cholesterol. Therefore, using freeze-fractured non-pigmented ciliary epithelium, the distribution of such arrays was compared to the distribution of membrane deformations induced by the sterol-probes filipin and digitonin in different domains of the basolateral plasma membrane. The distribution of orthogonal arrays of particles was homogeneous between different regions of the basolateral membrane of the non-pigmented ciliary epithelium, while the number of filipin-induced alterations was nearly 4 times higher in the membrane domains not in contact with the basal lamina than in domains in contact with it. Contrary to the homogeneous distribution of arrays, digitonin-induced deformations also differed markedly in these two basolateral membrane domains. Considering that a marked positive response to sterol probes implies a high sterol content, we conclude that orthogonal arrays of particles can occur in plasma membrane regions well-provided with cholesterol and not in direct contact with the basal lamina. Other possible roles of these arrays are discussed.

Animals↗
PubMed1986

Morphology of tight junctions in the ciliary epithelium of rabbits during arachidonic acid-induced breakdown of the blood-aqueous barrier.

A reversible breakdown of the blood-aqueous barrier in the iridial processes of rabbits has been induced by arachidonic acid as demonstrated by the passage of horseradish peroxidase at places through the tight junctions. Freeze-fracture images reveal very discontinuous P-face ridges. However, the analysis of complementary replicas demonstrates that discontinuities of P-face ridges are always complemented by particles or short bars found in the E-face furrows. Though the problem exists of correlating freeze-fracture images of the junctional structure to the focal passage of horseradish peroxidase, the data suggest that the discontinuities of P-face ridges cannot be the structural counterpart of the passage of horseradish peroxidase. Alternative pathways of horseradish peroxidase are discussed in context with the offset bifibrillary model of the junction.

Animals↗
PubMed1986

Selective and reversible breakdown of the tight junctional barrier in the rabbit ciliary body induced by arachidonic acid. A tracer and freeze-fracture study.

Arachidonic acid induced a reversible breakdown of the blood-aqueous barrier in the iridial processes of the rabbit ciliary body, whereas the ciliary processes were not affected under the conditions of this study. The focal passage of horseradish peroxidase through the tight junctions was demonstrated. In freeze-fracture images, this breakdown of the barrier function was associated with focal changes: an alteration in the geometry of the tight junctional network; an increase in the number of discontinuities of the P-face ridges and particles and short bars in the E-face furrows; an increase in the density of intramembranous particles within the junctional area. The significance of the ultrastructural alterations of the tight junctions as a structural counterpart of the physiological changes is discussed.

Animals↗
PubMed1984

Isolation and characterization of internalized glioma cell membranes.

A method for isolating plasma membranes based on the ability of cultured C6-glioma cells to phagocytize inert material such as polystyrene (latex) beads is described. The beads (phi 1.1 micron) were incubated for 16 h or 5 h. After several washings and homogenization of the cells, the beads with the surrounding membranes were isolated by use of a sucrose density gradient. The membranes were analyzed morphologically and biochemically. Morphological studies by means of light- and electron microscopy confirmed the intracellular localization of the beads. Enzymatic studies revealed that the specific activity of acid phosphatase decreased with shorter incubation periods (from 268.00 +/- 38.56 U X mg protein-1 X min-1 after 16 h to 125.12 +/- 9.10 after 5 h), whereas that of Na, K-ATPase showed the opposite trend (3.63 +/- 0.41 and 4.73 +/- 0.78 mumoles phosphate X mg protein-1 X h-1, respectively), indicating a lesser contamination with lysosomes. The main advantages of this procedure for membrane studies lie in purity and definite orientation ("inside-out") of the membranes.

Acid Phosphatase↗
PubMed1980

Further studies on the nature of red fluorescent structures in neuroblastoma monolayer cells vitally stained with acridine orange.

The nature of red fluorescent particles in vitally acridine orange stained C 1300 neuroblastoma monolayer cells was evaluated by electron microscopy, cytofluorometry, cytopharmacological and cell fractionation studies. At the ultrastructural level the distribution of red fluorescent granules correlated with that of the Golgi complex and Golgi derived structures during various stages of differentiation, mitosis, and under colcemid treatment. Cytopharmacological studies revealed that red fluorescence was displaced in a concentration and time dependent manner with the basic drugs chloroquine and quinacrine. Subcellular fractionation studies showed that acridine orange was concentrated in fractions that also contained the highest amount of acid phosphatase and electron dense vesicles. Vital acridine orange staining of neuroblastoma cells in culture can give information on the relationship between Golgi-derived vesicles and cell functions like proliferation and differentiation. The influence of drugs on these processes can be studied.

Acid Phosphatase↗
PubMedDate not supplied

[Intraocular pressure ten weeks after cataract surgery].

The effect of phacoemulsification and extracapsular cataract extraction on the intra-ocular pressure is analysed for several intra-operative factors. The mean intraocular pressure is significantly reduced ten weeks after the operation in comparison with the preoperative intraocular pressure. This reduction of the intraocular pressure is most significant for eyes with preoperative ocular hypertension and those eyes where leakage of the aqueous humour was evidenced during the immediate postoperative period.

Cataract Extraction↗