L Luciano

Hannover Medical School, Hannover, Lower Saxony, Germany

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Publications (134)181.61 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstrakt. Die Reissner-Membran aus dem Innenohr von Chinchillas wurde mit Hilfe der Gefrierätzungsmethode untersucht. Zonulae occludentes schließen endolymph-wärts den Raum zwischen den Epithelzellen ab. Sie bestehen aus 2 bis 8 übereinanderliegenden Kämmen bzw. Tälern und ähneln somit morphologisch denen zwischen den Marginalzellen der Stria vascularis, sind jedoch wesentlich schwächer ausgebildet als die zwischen den Basalzellen der Stria.
    Archives of Oto-Rhino-Laryngology 07/2009; 80(1-6):38-42.
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    ABSTRACT: Two new components of basal laminar deposit (BlamD) occurring in samples of submacular neovascular membranes surgically removed from patients with a wet (exudative) form of age-related macular degeneration are described. They are: (1) minute ribbon-like structures which occur singly and/or in a bunch and extend from the inner surface of the BlamD layer into the extracellular matrix (ECM) beneath the retinal pigment epithelium (RPE). The ribbons are composed of polarized molecules, aggregating in parallel, aligned transversally in register, morphologically similar to isolated collagen molecules of the short-chain type. Deeper in the BlamD but always close to its inner surface, aspects suggesting a transition between ribbons and (2) long-spacing collagen (LSC)-like aggregates characterized by periods bordered by a single dense band were observed. This band could arise from the globular domains of the polarized monomers, which assemble in parallel and display all their terminal extensions at the same end of each period resulting in the single dense band. The presence of ribbons and of LSC-like aggregates in the BlamD layer and the concomitant choroidal neovascularization (CNV) suggest that the events might be correlated. The newly formed vessels crossing Bruch's membrane and invading the BlamD layer could induce physicochemical changes in the ECM of the RPE, providing the required environmental conditions for the polymerization of collagen molecules into aggregates with the LSC-like pattern. With the deposition of new components, the thickness of BlamD increases and further impairs the supply of nutrients and oxygen, thus sustaining CNV.
    Cells Tissues Organs 01/2009; 190(3):170-81. · 1.96 Impact Factor
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    ABSTRACT: To correlate the functional results of macular translocation (MT) in a patient suffering from an adult-onset foveomacular vitelliform dystrophy (AFVD) with the microscopic findings of the surgically removed subfoveal retinal pigment epithelium (RPE). A 78-year-old woman with AFVD underwent MT with 360 degrees retinotomy 3-4 months after loss of reading ability. Most of the vitelliform material was lost during surgery; the subfoveal tissue was excised, fixed in aldehydes, postfixed in reduced OsO4 and embedded in epoxy resin. Semithin sections were stained with toluidine blue for light microscopy (LM) and thin sections with uranyl acetate and lead citrate for transmission electron microscopy (TEM). Postoperatively, the patient developed a retinal detachment complicated by proliferative vitreoretinopathy (PVR) requiring two additional vitreoretinal procedures before finally the silicone oil could be removed. Twenty-two months after MT the distance visual acuity was unchanged at 0.2; the near visual acuity had improved from less than 0.1 before MT to 0.4. The retina was completely attached. LM and TEM revealed serious alterations indicative of a breakdown of the outer layer of the retina. Through the present single case it is not possible to determine whether MT could be a therapeutic approach in patients with AFVD. The most important cause for the limited postoperative visual improvement seems to be a primary injury of the foveal function due to the AFVD. This is supported by the extensive subfoveal degeneration and necrosis affecting not only the RPE cells but also their basement membrane and the interposed basal laminar deposits.
    Albrecht von Graæes Archiv für Ophthalmologie 07/2004; 242(6):456-67. · 1.93 Impact Factor
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    ABSTRACT: The success or failure of the clearance of apoptotic cell remains depends on the ability of phagocytic cells to recognize, phagocytoze, and digest these remains prior to their lysis, which would cause tissue inflammation. We have recently shown that, after mass-induced apoptosis of guinea pig colonocytes in vivo, phagocytosis by resident macrophages, although efficient, does not prevent a pre-inflammatory response of the mucosa. The present study has investigated the cause(s) of this clearance failure. Immunohistochemistry and transmission electron microscopy were applied. Antibodies directed against the epithelial plasma membrane protein E-cadherin, the lysosomal membrane protein LAMP-1, and the lysosomal matrix protease cathepsin-D were used. The results revealed that: (1) anti-E-cadherin labeled the membrane of epithelial apoptotic bodies internalized in macrophages, (2) double and triple labeling demonstrated that the anti-LAMP-1 and anti-cathepsin-D antibodies recognized and were co-localized in lysosomes and/or phagolysosomes in macrophages but left E-cadherin-positive structures unlabeled, (3) the more numerous were the E-cadherin-positive inclusions in macrophages, the smaller was the number of those that stained positive for lysosomal markers. In parallel with electron microscopy, these findings showed that not all apoptotic bodies phagocytozed by macrophages were subsequently digested, suggesting that the phagocytotic ability of these cells was not matched by their digestive capability.
    Cell and Tissue Research 05/2004; 316(1):77-86. · 3.68 Impact Factor
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    Stephanie Groos, Enrico Reale, Liliana Luciano
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    ABSTRACT: The present study was designed to evaluate different techniques for the in situ detection of apoptosis in human and rat small intestinal epithelium. The techniques included light microscopy (LM) and transmission electron microscopy (TEM) observation of epoxy resin-embedded tissue, scanning electron microscopy (SEM), TUNEL assay, and antibodies directed against caspase cleavage products of caspase 3, cytokeratin 18 (CK 18), and apoptotic single-strand DNA (ssDNA). All techniques, if the labeling was positive, showed apoptotic cells exclusively at the villus tip. LM and TEM were the most reliable and revealed morphological signs typical of cells that have died via apoptosis. SEM indicated the extension of the process. The antibody recognizing cleaved caspase 3 could be considered an appropriate marker for apoptotic epithelial cells in human and rat small intestine. However, the majority of epithelial cells lining the proximal small intestinal villus contained only low levels of intact CK 18. Therefore, sufficient amounts of cleaved CK 18 for immunohistochemical detection were not generated during apoptosis, rendering the application of the antibody inappropriate. The antibody detecting formamide-denatured ssDNA in apoptotic cells was both suitable and reliable; however, the particular staining procedure used compromised the tissue preservation. In comparison to this, the TUNEL assay was less reliable. Although it was performed with a commercially available ready-to-use kit, its application conditions had to be adjusted for each specimen on the basis of the findings produced by other techniques.
    The Anatomical Record Part A Discoveries in Molecular Cellular and Evolutionary Biology 07/2003; 272(2):503-13.
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    ABSTRACT: The atrophy and architectural remodeling of the jejunal mucosa arising in adults receiving total parenteral nutrition (TPN) has been suggested to originate from a disturbance in tissue homeostasis. The present study aims at examining (1) whether there are differences in proliferation and apoptosis of epithelial cells between enterally and parenterally nourished patients and (2) whether the distribution pattern of extracellular matrix (ECM) proteins known to influence cell turnover along the the crypt-villus axis is changed after TPN. The mitotic frequency and the proliferation index [using an antibody against Ki-67 antigen (MIB 1)] were determined on epoxy semithin and paraffin sections, respectively. Morphological techniques and the TUNEL assay were applied to detect apoptotic events. Immunolocalization of collagen IV, laminin, fibronectin, tenascin, and collagen VI was performed on cryosections. After TPN the cell renewal was significantly enhanced, while epithelial cell death was drastically reduced. The comparison of TPN and EN patients revealed differences in the distribution patterns of the ECM proteins laminin, fibronectin, and tenascin along the crypt-villus axis. Moreover, after TPN an increased expression of collagen types IV and VI was observed. TPN in human adults is associated with alterations in epithelial cell turnover and changes in expression and/or localization of ECM proteins. Thus, the inverted route of nutrient supply in patients might modify environmental tissue conditions, which may influence the interactions between intestinal epithelial cells and the extracellular matrix.
    Journal of Surgical Research 03/2003; 109(2):74-85. · 2.02 Impact Factor
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    Liliana Luciano, Stephanie Groos, Enrico Reale
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    ABSTRACT: It has been suggested that brush cells (BCs), a distinct type of cell occurring in various epithelia of the respiratory and gastrointestinal tracts, may function as receptor cells. The major characteristics of BCs are a prominent brush border and an unusually highly ordered arrangement of cytoskeletal elements (F-actin, microtubules, and intermediate filaments). In this study we aimed to characterize the nature of the intermediate filaments in BCs by light and electron microscopic immunostaining. Gallbladder and stomach specimens from mice and rats, respectively, were fixed in various solutions, embedded either in paraffin or epoxy resin, and processed for immunodetection. Commercially available, well-characterized antibodies against neurofilaments, peripherin, and cytokeratin peptide 18 were used. The polyclonal antiserum cocktail to neurofilaments was applied as a supplement in a double-labeling procedure with anti-actin and anti-cytokeratin 18 antibodies. The results demonstrate that the BCs of both organs express two types of intermediate filaments, i.e., neurofilaments and cytokeratin 18 filaments, and that these have a compartmentalized distribution in the cytoplasm. BCs do not express peripherin. The immunodetection of intermediate filaments distinctive for mature neurons in BCs supports their putative receptor function. The co-expression of neurofilaments and cytokeratins is shown for the first time in healthy tissues.
    Journal of Histochemistry and Cytochemistry 03/2003; 51(2):187-98. · 2.26 Impact Factor
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    ABSTRACT: Our previous investigations demonstrated a rapid, massive apoptosis of colonocytes after butyrate deprivation. However, while in vitro apoptotic bodies and cells were sludged at the epithelial surface, in vivo they were phagocytosed by the resident macrophages. In the present study the guinea pig colon was perfused in vivo in the presence or absence of butyrate with the aim of identifying the cells involved in the removal of apoptotic material and the method of clearance. Morphological, immunohistochemical and DNA fragmentation analyses were applied. The results demonstrated massive apoptosis of colonocytes in the absence of butyrate. The resident macrophages were tightly clustered below the surface epithelium. Aided by cytoplasmatic projections they phagocytosed and transported apoptotic material from the epithelial intercellular spaces into their bodies. Apparently, the macrophages could not cope with the great amount of apoptotic material they had to eliminate: the recruitment of circulating monocytes occurred. This was revealed by the application of antibodies directed against MAC 387, CD68 (PG-M1), and S-100, which detected distinct monocyte/macrophage populations in the lamina propria. The recruited cells were phenotypically different from resident macrophages, their occurrence being typical in inflamed tissues. In conclusion, butyrate deprivation in vivo led to untimely death of colonocytes and triggered changes in the lamina propria indicative of an inflammatory response.
    Cell and Tissue Research 10/2002; 309(3):393-407. · 3.68 Impact Factor
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    S Groos, E Reale, L Luciano
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    ABSTRACT: Epoxy resins provide optimal tissue morphology at both the light and the electron microscopic level and therefore enable correlative studies on semithin and thin sections from the same tissue block. Here we report on an approach to retain these advantages for immunolabeling studies by adapting and combining well-known techniques, i.e., surface etching with sodium ethoxide and heat-mediated antigen retrieval. We propose a simple procedure for immunostaining semithin and thin epoxy resin sections. To check its applicability, well characterized, commercially available antibodies (against E-cadherin, alpha-catenin, and beta-catenin) were used on sections of human small intestine. By light microscopy, the immunostaining efficiency was compared on cryo-, paraffin, and epoxy semithin sections processed in parallel. The most detailed results were obtained on semithin sections, where the labeling precisely delineated the lateral plasma membrane of the enterocytes. At the electron microscopic level the procedure did not damage the structures and allowed an efficient, reproducible immunogold labeling extending homogeneously over exceptionally wide tissue areas. The three antibodies specifically labeled the zonula adherens of the junctional complex between epithelial cells and, in agreement with light microscopic observations, the lateral plasma membrane.
    Journal of Histochemistry and Cytochemistry 04/2001; 49(3):397-406. · 2.26 Impact Factor
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    ABSTRACT: The organization of the aggregates occurring in the stroma: (1) of the murine and human cornea after incubation in an ATP acidic solution; (2) of surgically excised epiretinal membranes (ERM); and (3) of the trabecular meshwork of monkey eyes was investigated morphologically and immunocytochemically on thin section electron microscopy. Morphology. The aggregates in the cornea appeared as cross-banded fibrils. The bands were uniformly electron dense (single banded form); they were separated from each other by interbands consisting of a bundle of filaments emerging in cross section as small areas of randomly assembled dot-like structures. In the ERM, most of the aggregates stood out as heteromorphic cross-banded bodies showing dense bands with electron denser borders (double banded form) and interbands composed of longitudinally oriented, parallel sheets or laminae of amorphous material enclosing thin, similarly oriented filaments. These extended, thinner and double in number (since interlacing with similar components of the opposite sheet), into the pale central zone of the dense band. The aggregates of the trabecular meshwork were heteromorphic, had uniformly dense bands (single banded form as in the cornea), but their interbands displayed longitudinal sheets (as the ERM aggregates). Immunocytochemistry revealed type VI collagen in the three eye aggregates with gold particles preferentially localized at the interbands. The specificity of the antibodies used was tested by Western blot analysis of type VI collagen samples extracted from human placenta and on homogenates of human cornea. In conclusion, the results indicate that the tetramers of type VI collagen may aggregate differently into structures with distinct supramolecular arrangements. These are illustrated in schematic drawings.
    Matrix Biology 03/2001; 20(1):37-51. · 3.19 Impact Factor
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    ABSTRACT: The structure of the membrana limitans interna (MLI) in the region of the macula has been investigated by electron microscopy in (a) 2 enucleated human adult eyes and (b) 38 surgically removed samples associated with an epiretinal membrane (ERM). In the enucleated eye, the glia cells were vitrad bordered either by the lamina rara or, directly, by the lamina densa. Both extended into a coarse network whereby the lamina densa, through repeated branches and anastomoses, delimited large meshes, the lamina rara formed their contents. High magnification revealed that both meshes and contents of this network were composed by a further, finer network. It is suggested that strips and small openings of the finer network are homologous to the cords and intercordal spaces, respectively, which have been indicated as the common, basic structures of most of the basement membranes. The MLI excised with an ERM had the same structure. In some of the ERM associated with a macular hole, myofibroblasts prevailed among the cells. They showed indented nucleus, stress fibers abuting on the plasma membrane or in apparent continuity with bundles of extracellular filaments (microtendons), gap junctions. The cells lay on or were surrounded by a discontinuous basement membrane.
    Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 02/2001; 106(2 Suppl 1):509-15.
  • S Groos, G Hünefeld, L Luciano
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    ABSTRACT: In the human small intestine, proliferation, migration, differentiation and death of epithelial cells take place in separated compartments along the crypt-villus axis. It has been shown in different cell systems that these basic biological activities are influenced by extracellular matrix proteins. To investigate possible relationships in the epithelium of the human adult small intestine we examined immunohistochemically the distribution of type IV collagen, laminin, fibronectin and tenascin, and compared the sites of their expression with the various cell activities. Epithelial cell proliferation and cell death have been detected by an antibody against Ki-67 and the TUNEL-assay, respectively. The results show that Ki-67 staining is restricted to the crypts and TUNEL-positive cells are only present in the upper villus region. Type IV collagen is uniformly present in the epithelial basement membrane along the crypt-villus axis providing a scaffold for other components of the extracellular matrix. Laminin appears to be associated with epithelial cell differentiation, since it is strongly expressed in the villus basement membrane but only weakly underneath the crypt epithelium. Although fibronectin displays a staining pattern similar to that of laminin, it might rather be responsible for cell adhesion. Strong indications have been found that tenascin could be related to epithelial cell death since it was particularly expressed at the villus tip, where the cells undergo apoptosis.
    Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 02/2001; 106(2 Suppl 1):353-61.
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    ABSTRACT: Short-chain fatty acids (SCFA) in particular butyrate are regarded as an energy source acting in beneficial, protective manner on the colonic mucosa. Previous investigations showed that the colonic mucosa bathed in Ussing chamber with a solution lacking butyrate induced massive apoptosis of epithelial cells. The apoptotic material (bodies and cells) was shed at the mucosa surface. In the present study we aimed to investigate the effects caused in vivo on the colonic mucosa by the absence of butyrate. For this purpose the colon of guinea pigs was perfused in situ with solutions either containing or lacking butyrate. The results show that within 2h of perfusion without butyrate a large amount of epithelial cells underwent apoptosis as in the in vitro experiments. However, apoptotic material instead to be extruded at the epithelial surface accumulates into the intercellular spaces from which it becomes removed by an unusual high number of macrophages. These, engorged with phagocytozed material, lie assembled in a layer below the epithelium. Similar alterations have not been observed after perfusion in the presence of butyrate. The results suggest that this SCFA may protect the colonic mucosa in that it prevents apoptosis. The alterations occurring during 2h of its absence allow to assume that a protracted butyrate deprivation may lead to a breakdown of the integrity of the mucosa thus influencing differently the activity of the macrophages.
    Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 02/2001; 106(2 Suppl 1):347-52.
  • Liliana Luciano, Enrico Reale
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    ABSTRACT: The brush cells (BC) are the second most frequent cellular component of the epithelium of the mouse gallbladder. They have a topographical distribution, being present in large numbers toward the neck and in the fundic regions of the organ and are scattered in the body. Serial section studies demonstrate that BC have a characteristic shape consisting of a narrow apical portion, bulky body and basal cytoplasmic projections. BC are located obliquely among the principal cells. Scanning electron microscopy demonstrates that the microvilli forming the prominent brush border, after which the cell was named, have a triangular arrangement. Due to their size and stiffness, the microvilli of BC have more similarity with stereocilia of sensory cells than with conventional microvilli. Furthermore freeze-fracture replicas demonstrate that, like stereocilia, the P face of the microvilli plasma membrane of BC is smoother than the E face but several intramembranous particles form small aggregates on the microvillus tip of both P and E faces. Numerous intramembranous particles are scattered on the lateral plasma membrane. An unusual, spatially organized cytoskeleton characterizes the apical cytoplasm of BC. The use of the appropriate fixative reveals that it consists of bundles of actin filaments originating from the axis of the apical microvilli and stretching continuously up to the supranuclear region of the cell. Microtubuli, also assembled in bundles, flank in alternating manner the actin filaments over their whole course. Due to the strong parallel arrangement of both cytoskeletal structures, the apical cytoplasm of the BC assumes a typical stiffness, observable in both thin sections and freeze-fracture replicas. A variable number of vesicles of different size are aligned between the bundles of actin filaments and microtubuli; their shape is highly influenced by the fixative used. Intraluminal injection of horseradish peroxidase demonstrates that these vesicles are not resorptive as they are not filled by the tracer. The BC possess a large number of lateral microvilli. These, whether single or in pairs, are rigid cytoplasmic protrusions that leave the lateral surface of the cell in all directions and penetrate deeply into the cytoplasm of the adjacent principal cells. The bundle of actin filaments emanating from each lateral microvillus extends at different angles into the cytoplasm. A conspicuous amount of bundles of 10 nm filaments is intertwined around the nucleus and extends toward the desmosomes of the lateral plasma membrane and into the basal cellular body. Arguments are considered in support of the view that interactions between the plasma membrane with its differentiations on the one hand and the cytoskeleton elements on the other hand, play a key role in the function of BC as a receptor (sensory) cell.
    Microscopy Research and Technique 10/1997; 38(6):598-608. · 1.59 Impact Factor
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    ABSTRACT: The recommended treatment for full-thickness macular holes is removal of the posterior hyaloid and sometimes the epiretinal membrane from the retina during vitrectomy in order to release the assumed intravitreous traction. We have employed a technique involving the additional removal of the membrana limitans interna (MLI) from the retina in the vicinity of the macular hole. We report on our clinical results and ultrastructural findings. Between December 1995 and July 1996, we performed vitrectomies on 39 eyes of 37 patients with full-thickness macular hole. After removal of the attached posterior hyaloid, a specially developed forceps was used to remove a circular area of the MLI approximately three to four disc diameters in size. At the conclusion of the operation, 20% C3F8 gas was injected and the patient instructed to stay in a prone position for 8 days. Intraoperatively, "rhexis" of the MLI only rarely produced bleeding or recognizable retinal edema. Complete closure of the hole was observed postoperatively in 36 of the 39 eyes (92%). A visual improvement of at least two lines was achieved in 77% of eyes with successful closure. Pigment irregularities or edematous changes could not be detected either clinically or by fluorescein angiography in any of the 39 eyes. Electron microscopy was performed on 23 of the membranes. The salient feature was the MLI. Canals leading from the inner to the outer surface of the MLI contained Müller cell processes with clear signs of necrosis or degeneration. On the vitreous side, the MLI usually exhibited myofibroblasts. The MLI was successfully removed in all 39 eyes with a full-thickness macular hole. This procedure led to very good anatomic and functional results. It remains for future studies to determine the pathogenic significance of the necrotic processes detected by electron microscopy in the MLI canals.
    Der Ophthalmologe 09/1997; 94(8):545-51. · 0.53 Impact Factor
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    ABSTRACT: Zur Behandlung von durchgreifenden Makulalöchern wird allgemein empfohlen, bei der Vitrektomie die hintere Glaskörperrinde und ggf. epiretinale Membranen von der Netzhaut zu entfernen, um die Makula von den vermuteten intravitrealen Zugkräften zu entlasten. Zusätzlich zu diesen Strukturen haben wir seit einiger Zeit auch noch die Membrana limitans interna (MLI) in der Umgebung des Foramens von der Netzhaut abgezogen. Über die klinischen Ergebnisse und die ultrastrukturellen Befunde der entfernten MLI wird berichtet. Material und Methoden: Zwischen Dezember 1995 und Juli 1996 wurde bei 39 Augen von 37 Patienten mit einem durchgreifenden Makulaforamen eine Vitrektomie durchgeführt. Nach Entfernung der noch nicht abgehobenen Glaskörperrinde wurde bei allen 39 Augen mit einer speziell entwickelten scharfen Pinzette ein etwa 3 – 4 Pupillendurchmesser großes Areal der MLI kreisrund von der Makula abgezogen. Die ,,Rhexis`` der MLI führte intraoperativ nur vereinzelt zu Blutungen oder einem erkennbaren Netzhautödem. Am Ende der Operation wurde 20%iges C3F8-Gas injiziert und dem Patienten für 8 Tage Bauchlage verordnet. 23 Membranen wurden elektronenmikroskopisch untersucht. Ergebnisse: In 36 der 39 Augen (92%) fand sich postoperativ ein vollständiger Verschluß des Foramens. Eine Visusverbesserung um mindestens 2 Zeilen wurde in 77% der Augen mit erfolgreichem Lochverschluß erzielt. Pigmentunregelmäßigkeiten oder ödematöse Veränderungen ließen sich in keinem dieser 39 Augen weder klinisch noch fluoreszenzangiographisch erkennen. Die Feinstruktur der entfernten Membranen zeigte als gemeinsamen Hauptbestandteil die MLI. Kanäle mit Resten von Fortsätzen von Müller-Zellen zogen von der inneren zur äußeren Oberfläche der MLI. Diese Fortsätze zeigten deutliche Zeichen einer Nekrose oder Degeneration. Vitreumwärts trug die MLI meist Myofibroblasten. Schlußfolgerungen: Bei allen 39 Augen mit durchgreifenden Makulaforamina war die gezielte Entfernung der MLI möglich. Sie führte zu sehr guten anatomischen und funktionellen Ergebnissen. Inwieweit die bei der ultrastrukturellen Untersuchung aufgefallenen nekrotischen Müller-Zell-Fortsätze in Kanälen der MLI pathogenetische Bedeutung haben, müssen weitere Untersuchungen zeigen. The recommended treatment for full-thickness macular holes is removal of the posterior hyaloid and sometimes the epiretinal membrane from the retina during vitrectomy in order to release the assumed intravitreous traction. We have employed a technique involving the additional removal of the membrana limitans interna (MLI) from the retina in the vicinity of the macular hole. We report on our clinical results and ultrastructural findings. Materials and methods: Between December 1995 and July 1996, we performed vitrectomies on 39 eyes of 37 patients with full-thickness macular hole. After removal of the attached posterior hyaloid, a specially developed forceps was used to remove a circular area of the MLI approximately three to four disc diameters in size. At the conclusion of the operation, 20% C3F8 gas was injected and the patient instructed to stay in a prone position for 8 days. Results: Intraoperatively,``rhexis'' of the MLI only rarely produced bleeding or recognizable retinal edema. Complete closure of the hole was observed postoperatively in 36 of the 39 eyes (92%). A visual improvement of at least two lines was achieved in 77% of eyes with successful closure. Pigment irregularities or edematous changes could not be detected either clinically or by fluorescein angiography in any of the 39 eyes. Electron microscopy was performed on 23 of the membranes. The salient feature was the MLI. Canals leading from the inner to the outer surface of the MLI contained Müller cell processes with clear signs of necrosis or degeneration. On the vitreous side, the MLI usually exhibited myofibroblasts. Conclusions: The MLI was successfully removed in all 39 eyes with a full-thickness macular hole. This procedure led to very good anatomic and functional results. It remains for future studies to determine the pathogenic significance of the necrotic processes detected by electron microscopy in the MLI canals.
    Der Ophthalmologe 07/1997; 94(8):545-551. · 0.53 Impact Factor
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    ABSTRACT: Butyrate stimulates proliferation and suppresses differentiation in normal colonic epithelial cells. Because the involved intracellular signaling mechanisms are unclear, this study investigated certain molecular effects of butyrate. Tissue sheets from guinea pig proximal colon were incubated in Ussing chambers in the presence and absence of butyrate. Colonic tissues were examined by scanning and transmission electron microscopy, DNA laddering, Western blots, and immunohistochemistry. After incubation of the colonic mucosa for 150 minutes without butyrate, morphological studies showed massive apoptosis of colonocytes. Simultaneously, these colonocytes exhibited a significant oligonucleosomal DNA fragmentation. In contrast, addition of physiological concentrations of butyrate (10 mmol/L) to colonic sheets showed no detectable DNA fragmentation within 150 minutes. Western blot analysis showed little if any difference in the level of Bcl-2 expression in colonocytes incubated with or without butyrate up to 150 minutes. In contrast, expression of Bax proteins continuously increased after 45 minutes without butyrate and reached a fivefold induction after 150 minutes compared with cells incubated in the presence of butyrate. Moreover, immunohistochemistry using an anti-Bax antibody system showed enhanced labeling of the epithelial colonocytes in the absence of butyrate. Removal of butyrate induces increased expression of Bax proteins paralleled by rapid apoptosis of colonocytes in vitro.
    Gastroenterology 03/1997; 112(3):875-81. · 12.82 Impact Factor
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    ABSTRACT: Butyrate exerts a trophic effect on the colonocytes and plays a protective role in ulcerative colitis. In the present study, we investigated the effect of butyrate withdrawal on the colonic mucosa of the guinea-pig. The samples were mounted in Ussing chambers and bathed for 45, 60, 90 and 150 min with standard Ringer solution with or without sodium butyrate. Light and electron microscopy for morphology, electrophysiological methods for testing tissue function, histochemistry using the TUNEL method for localization of apoptotic cells and flow cytometry for cell cycle analysis were applied. Morphological observations revealed that butyrate deprivation caused a time-dependent hypoplasia and a rapid triggering of massive apoptosis as substantiated by the TUNEL assay. The epithelium, however, did not show discontinuities at any time. Electrophysiological data confirmed that no leakage of the epithelium had occurred. In the control specimens, the mucosa underwent a moderate reduction in height; apoptotic epithelial cells were infrequently observed. Cell cycle analysis of colonocytes isolated from the mucosa deprived of butyrate revealed a decrease in the percentage of cells occupying each phase of the cycle, especially the G0/G1 phase. Thus, in the absence of butyrate, apoptosis was enhanced and cell renewal reduced. The trophic protective action exerted by butyrate in both physiological and pathological conditions could derive from its capacity to modulate survival and death of colonocytes.
    Cell and Tissue Research 11/1996; 286(1):81-92. · 3.68 Impact Factor
  • A Scriba, L Luciano, B Steiniger
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    ABSTRACT: Satisfactory purification of rodent monocytes in suspension has not been achieved up to now because in rats and mice these cells occur as a minor population of peripheral blood leukocytes overlapping with lymphocytes in size and density. We describe a two-step procedure for the isolation of monocytes from rat blood with high yield and purity. This method permits the recovery of more than 90% of monocytes collected by perfusion of the vasculature and avoids loss of major subpopulations. Percoll density gradient centrifugation of perfusate cells is combined with subsequent indirect immunomagnetic depletion of lymphocytes using an antibody cocktail. The method described produces more than 90% pure rat monocytes.
    Journal of Immunological Methods 03/1996; 189(2):203-16. · 2.23 Impact Factor
  • S Groos, G Hunefeld, L Luciano
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    ABSTRACT: In animal experiments total parenteral nutrition induces an atrophy of the small intestinal mucosa. In humans morphological data are few and controversial. Therefore, the aim of this study was to investigate the effect of parenteral nutrition on the intestinal mucosa of human adults. For this purpose samples of the proximal jejunum of a) patients with chronic pancreatitis receiving total parenteral nutrition as presurgical treatment, b) enterally nourished patients without (controls) and c) with chronic pancreatitis were compared using light and scanning electron microscopy. Statistical differences were assessed applying computer-assisted morphometry. The results demonstrated that the thickness of the jejunal mucosa decreased already in enterally nourished patients with chronic pancreatitis. However, after total parenteral nutrition the decrease (atrophy) was enhanced due to a strong reduction in villus height albeit the crypt length increased. In addition, scanning electron microscopy revealed distinctive changes in mucosal surface pattern, whereby finger-like villi were replaced by leaf-like villi and by long, winding bifurcating ridges. Cell shedding was absent. In conclusion, total parenteral nutrition in humans induces 1) an atrophy and 2) a remodelling of the intestinal mucosa (epithelium and lamina propria) with a decrease in the absorbing surface. These alterations involve both cell proliferation and cell shedding. The response of the mucosa to parenteral nutrition is immediate and the effect of the treatment in bringing about morphological alterations is more efficacious at the beginning than in the successive period. The basic disorder (chronic pancreatitis) of the patients nourished parenterally contributes to mucosal atrophy, but not to remodelling.
    Journal of submicroscopic cytology and pathology 02/1996; 28(1):61-74.

Publication Stats

1k Citations
181.61 Total Impact Points

Institutions

  • 1972–2009
    • Hannover Medical School
      • • Centre for Anatomy
      • • Central Electron Microscopy Laboratory
      Hannover, Lower Saxony, Germany
  • 2004
    • Goethe-Universität Frankfurt am Main
      Frankfurt, Hesse, Germany
  • 1989–1994
    • Medical University of South Carolina
      • Department of Medicine
      Charleston, SC, United States
    • Alfried Krupp Krankenhaus
      Essen, Lower Saxony, Germany
  • 1986
    • Jules Stein Eye Institute
      Maryland, United States
  • 1981
    • University of California, Los Angeles
      • Department of Medicine
      Los Angeles, CA, United States
  • 1971–1976
    • University of Milan
      Milano, Lombardy, Italy
    • University of California, San Francisco
      • Department of Ophthalmology
      San Francisco, California, United States
  • 1974
    • Università degli Studi di Bari Aldo Moro
      Bari, Apulia, Italy
  • 1967–1971
    • Heinrich-Heine-Universität Düsseldorf
      Düsseldorf, North Rhine-Westphalia, Germany
  • 1963–1964
    • University of Lausanne
      Lausanne, Vaud, Switzerland