Liver-intestine cadherin: molecular cloning and characterization of a novel Ca(2+)-dependent cell adhesion molecule expressed in liver and intestine.

A novel member of the cadherin family of cell adhesion molecules has been characterized by cloning from rat liver, sequencing of the corresponding cDNA, and functional analysis after heterologous expression in nonadhesive S2 cells. cDNA clones were isolated using a polyclonal antibody inhibiting Ca(2+)-dependent intercellular adhesion of hepatoma cells. As inferred from the deduced amino acid sequence, the novel molecule has homologies with E-, P-, and N-cadherins, but differs from these classical cadherins in four characteristics. Its extracellular domain is composed of five homologous repeated domains instead of four characteristic for the classical cadherins. Four of the five domains are characterized by the sequence motifs DXNDN and DXD or modifications thereof representing putative Ca(2+)-binding sites of classical cadherins. In its NH2-terminal region, this cadherin lacks both the precursor segment and the endogenous protease cleavage site RXKR found in classical cadherins. In the extracellular EC1 domain, the novel cadherin contains an AAL sequence in place of the HAV sequence motif representing the common cell adhesion recognition sequence of E-, P-, and N-cadherin. In contrast to the conserved cytoplasmic domain of classical cadherins with a length of 150-160 amino acid residues, that of the novel cadherin has only 18 amino acids. Examination of transfected S2 cells showed that despite these structural differences, this cadherin mediates intercellular adhesion in a Ca(2+)-dependent manner. The novel cadherin is solely expressed in liver and intestine and was, hence, assigned the name LI-cadherin. In these tissues, LI-cadherin is localized to the basolateral domain of hepatocytes and enterocytes. These results suggest that LI-cadherin represents a new cadherin subtype and may have a role in the morphological organization of liver and intestine.

A human-SCID mouse model for allergic immune response bacterial superantigen enhances skin inflammation and suppresses IgE production.

Chronic skin colonization with Staphylococcus aureus is a well-known feature in atopic dermatitis. The aim of this study was to develop a human-SCID mouse model to analyze the possible role of bacterial superantigens in human allergic immune responses under in vivo conditions. SCID mice were reconstituted with peripheral blood mononuclear cells (between 2 and 9 x 10(7) cells per mouse) from atopic dermatitis patients sensitized to house dust mite allergen (Der p). Total and Der p specific antibody production required the following conditions: (i) injection of Der p; (ii) presence of CD14+ antigen-presenting cells; and (iii) IL-4 as shown by the inhibitory effect of human soluble IL-4 receptor on immunoglobulin E production. This model was used to study the immunomodulatory effects of the superantigen staphylococcal enterotoxin B in comparison with Der p. In intraperitoneally reconstituted human-SCID mice, topical treatment was ineffective in inducing skin inflammation. Therefore, additionally to intraperitoneal transfer, peripheral blood mononuclear cells from atopic donors were also injected intradermally. Such reconstituted SCID mice were then exposed via the skin to either Der p, staphylococcal enterotoxin B, or a combination of both. Maximal effects on epidermal inflammation and dermal T cell infiltration were obtained with staphylococcal enterotoxin B and Der p. Staphylococcal enterotoxin B alone was less effective and Der p only stimulated dermal T cell infiltration. These findings support the hypothesis that bacterial superantigens can act as trigger factors in allergic skin inflammation.

Comparison of four methods for mass hepatocyte isolation from pig and human livers.

Using the pig liver, parameters for large scale hepatocyte isolation were studied in order to develop a technique suitable for human organs. These investigations led to a 5-step modification of the original 2-step method. Four groups were compared. A nonenzymatic EDTA perfusion technique has been shown to be inconvenient for mass cell isolation. The enzymatic 2-step perfusion, using 0.08% collagenase and 20-kg pigs, resulted in a mean hepatocyte viability of 61 +/- 1.9%, with a mean yield of 67 +/- 6.5% wet weight of the organ. The enzymatic 5-step method resulted in a mean hepatocyte viability of 74 +/- 1.7% with a mean yield of 80 +/- 1.8% wet weight. Five-step portal venous perfusion in combination with arterial perfusion resulted in 76 +/- 2.6% viability with a yield of 82 +/- 6.1%. The results were dependent on collagenase concentration and weight of the donors, improving with decreasing body weight. The 5-step method with combined arterial and portal vein perfusion developed for pig liver was used for mass human liver cell isolation with a minimum viability of 57% and a minimum yield of 58% wet weight.

[Animal experimental studies on the application of dynamic computed tomography to liver tumors]. / Tierexperimentelle Studien zum Einsatz der dynamischen Computertomographie bei Lebertumoren.

Experiments on rabbits with implanted liver tumours have shown that iso-dense tumours, which are not visible on CT, may be demonstrated by dynamic CT following intravenous contrast injection. They may appear as hypodense areas during a period of maximal organ perfusion, if the tumours have not taken up the contrast. The ability to recognise tumours depends largely on intravascular and, only to a smaller extent, on interstitial contrast enhancement.

[High-resolution magnetic resonance tomography (HR-MRT) of the pleura and thoracic wall: normal findings and pathological changes]. / Hochauflösende Magnetresonanztomographie (HR-MRT) von Pleura und Thoraxwand: Normalbefund und pathologische Veränderungen.

AIM: To determine the value of high-resolution MRI in pleural and chest wall diseases, the normal and pathologic costal pleura and adjacent chest wall between paravertebral and the axillary region were examined with contrast enhanced high-resolution T1-weighted MRI images using a surface coil. MATERIAL AND METHODS: Normal anatomy was evaluated in 5 healthy volunteers and a normal specimen of the thoracic wall, and correlation was made with corresponding HR-CT and histologic sections. CT-proved focal and diffuse changes of the pleura and the chest wall in 36 patients underwent HR-MRI, and visual comparison of MRI and CT was done retrospectively. RESULTS: Especially sagittal T1-weighted HR-MRI images allowed accurate delineation of the peripleural fat layer (PFL) and the innermost intercostal muscle (IIM), which served as landmarks of the intact inner chest wall. PFL and IIM were well delineated in 3/4 patients with tuberculous pleuritis, and in all 7 patients with non-specific pleuritis, as opposed to impairment of the PFL and/or the IIM, which was detected in 15/18 malignancies as a pattern of malignant chest wall involvement. In one case of tuberculous pleural empyema with edema of the inner chest wall HR-MRI produced false positive diagnosis of malignant disease. CONCLUSION: HR-MRI images improved non-invasive evaluation of pleural and chest wall diseases, and allowed for differentiation of benign and malignant changes.

Membranes as substrates for hepatocyte adhesion in liver support bioreactors.

Fourteen membranes out of cellulose (CuprophanR), polyamide and polypropylene were compared in a cytocompatibility test using the cytokinetics and cytomorphology of primary hepatatocytes as parameters. Additionally, the impact of coating the membranes with collagen or fibronectin was investigated. Hepatocytes were not able to attach in acceptable amounts on investigated cellulose membranes. On polyamide and polypropylene membranes a sufficient cell seeding was possible. Coating with collagen or fibronectin improves the attachment and spreading on all membranes. Differences between collagen and fibronectin were detected, observing the morphology of the cells: on collagen, most of the cells spread, whilst on fibronectin, most of the cells spread and flattened polygonally. If the adhesion of hepatocytes prolongs their metabolic function, a large adhesion surface in bioreactors is necessary. To reach a high surface area for cell adhesion in bioreactors one possibility is the use of polyamide and polypropylene membranes.

Comparison of hollow fibre membranes for hepatocyte immobilisation in bioreactors.

Various hollow fibre membranes of polyamide, cellulose and polypropylene were investigated as potential substrata for hepatocyte immobilisation in bioreactors for hybrid liver support systems. Membranes were subjected to a cytocompatibility test in which the attachment and morphology of primary hepatocytes were evaluated. The effect of coating with collagen and fibronectin was also studied. Adequate cell immobilisation was possible on polypropylene and polyamide membranes even without coating. The flattening process of the cells was dependent on the material and the coating. The incorporation of porous polypropylene hollow fibres in hybrid liver cell bioreactors and their specific permeability properties could also offer means for cell oxygenation, metabolite distribution and immuno-isolation purposes.

Hepatocyte aggregate culture technique for bioreactors in hybrid liver support systems.

Utilizing a modified culture technique for hepatocytes, a high performance suspension culture is possible in which hepatocytes spontaneously form cell aggregates. The aggregates of 20-100 cells have been histologically confirmed to hold a three-dimensional structure, they show a long-term external metabolism and a survival time comparable with standard adhesion cultures. This technique has several advantages in the construction of large scale bioreactors for hybrid liver support systems.

Prevention of catheter-related infections by a new, catheter-restricted antibiotic filling technique.

Catheter-related infections pose a hazard to both humans and laboratory animals. The aim of this study was to develop a technique preventing bacterial colonization of intravascular catheters. In 27 dogs a total of 70 catheters were implanted. On an average catheters were used for 207 days. Three protocols were compared: (1) flushing the catheters with a heparinized solution; (2) filling only the catheter lumen with alpha-chymotrypsin solution (225 units/ml); (3) filling only the catheter lumen with a solution containing a mixture of the aminoglycoside antibiotic gentamicin (20 mg/ml) and chymotrypsin (225 units/ml). Catheter fillings were always withdrawn before catheter use. Catheter exit sites were all treated with povidone iodine ointment once a day. Body temperatures and weights were recorded, bacteriological and electron microscopical examinations of catheters performed. Without gentamicin filling all catheters were colonized after a few weeks. The dogs showed clinical signs of chronic bacteraemia. Gentamicin filling eradicated colonization. No further bacteraemia was observed. We conclude that filling only the catheter lumen with a concentrated solution of chymotrypsin and gentamicin, combined with measures to prevent infections via the subcutaneous catheter tunnel, is an effective and safe technique to prevent catheter-related infections.

[Scanning microscopy and immunohistochemical studies of an explanted phacic posterior chamber lens (ICL-M, STAAR)]. / Rasterelektronenmikroskopische und immunhistochemische Untersuchungen einer explantierten phaken Hinterkammerlinse (ICL-M, STAAR).

OBJECTIVE: This study was performed to find out if an explanted phacic collamer IOL (ICL/STAAR) showed structural or surface quality changes after an intraocular implantation. MATERIAL AND METHODS: We explanted an ICL 6 months after implantation and compared it to a new reference lens using scanning electron microscopy and immunohistochemical investigations. RESULTS: The explanted ICL showed no changes in comparison to a new ICL except for a coating with an unidentified material. Both the new and explanted ICL presented grooves on the surface and superficial holes of unknown origin measuring roughly 10 mu. Neither pigment nor macrophages could be found on the explanted lens. Although the lens material contained 0.1% collagen, the immunohistochemical staining for collagen was negative. CONCLUSIONS: The collagen content of the ICL could not be proven using immunohistochemistry. No changes were found between the new and the explanted lens, except for a coating of the explanted lens with an unidentified material.

Ultrastructure of a virilizing ovarian Leydig-cell-tumor. Hilar cell tumor.

A case of virilizing ovarian hilus cell tumor (Leydig-cell tumor) in a 37 year old female was studied by light and electron microscopy. The ultrastructural features of this rare and almost always benign tumor are compared with those reported in the literature and with findings in normal and neoplastic interstitial cells of the testis. Tubulovesicular hyperplasia and formation of whorl structures of the endoplasmatic reticulum together with the presence of exocytosis vesicles on the cell surface may be the morphological manifestation of endocrine activity of the tumor. The identity of ultrastructural and optical diffraction characteristics of the crystal inclusions in both cells (hilar and testicular interstitial) favours the assumption of an homology of both cells and their neoplasms.

[Perfluorochemical-emulsion (fluorocarbon-43) as blood gas carrier--fate of the substance after intravenous injection in rat (author's transl)]. / Verbleib des blutgastransportierenden Fluorkohlenwasserstoffes Fluorocarbon-43 im Organismus bei parenteraler Anwendung in Tierversuch.

The present paper concerns light and electron microscopic studies on cellular uptake and deposition of the oxygen and carbondioxide carrying substance "Fluorocarbon-43" after intravenous injection in rats. Phagocytosis of "Fluorocarbon-43" by blood monocytes, histiocytes, endothelial macrophages (i.e.v. Kupffersche cells) and hepatocytes as well, could be demonstrated. In our experiments cellular storage of the substance was detectable even six month after injection. In the lumina and walls of alveoli migrating macrophages with storage vacuoles were found indicating pulmonary excretion of the substance. Maximum storage of "Fluorocarbon-43" caused cellular alterations and may induce interstitial fibrosis. The question whether long term incorporation of "Fluorocarbon-43" causes irreversible alteration of organs is still a matter of conjecture because of the prolonged half-live value of storage of this substance.

Long-term observation of PFC storage in organs of rats after various dosages.

The study reports long term observations concerning the proliferation of connective tissue and histological changes in the liver, spleen and lung of Wistar rats after intravenous injection of fluorocarbons (Fluosol-DA 20% and 35%). No elevated connective tissue values were observed after a single injection of 2.3-3.1 g fluorocarbons per kg body weight with F-DA 20% or 4.1-5.1 g/kg body weight with F-DA 35% at determination of the stroma using the hydroxyproline method. After repeated intravenous injections of F-DA 20% (up to 22 g fluorocarbons/kg body weight) and F-DA 35% (up to 31 g/kg body weight), elevated levels of hydroxyproline were found in the liver as proof of proliferation of connective tissue. When F-DA 20% was injected, normal levels of hydroxyproline were found even after one year. In neither case were quantitative changes in the connective tissue of the lungs observed. Representative results for the spleen could not be reported because of methodological reasons. Histological changes were demonstrated and discussed. Since the given doses of F-DA 35% were significantly higher than those normally used, we can assume that the connective tissue proliferation occurs only after a very high limit is exceeded.

Tumor of mesonephric origin in a diverticulum of the urethra. An ultrastructural study.

A case of a rare tumor arising in a diverticulum of the urethra was studied. Light microscopy revealed the typical structures of mesonephric tumor with obvious infiltration of the muscularis. Electron microscopic appearance indicated that the tumor cells were immature and not totally characteristic of any tissue of origin. Apart from appearances suggesting rapid growth, cellular inclusions of various appearance were found.

[Ultrastructural studies of fluorocarbon excretion and uptake in the lung (author's transl)]. / Elektronenoptische Untersuchungen zur Fluorocarbon-Ausscheidung und Aufnahme in der Lunge.

Certain fluorochemicals are under discussion as synthetic substitutes for erythrocytes because of their high binding capacity for blood gases. The excretion of fluorocarbons occurs predominately in the lungs. As a part of this process of excretion, active cellular transport can be demonstrated by ultrastructural examination. Chronic organ defects, especially lung fibrosis, were not detected.

[Light and electron microscopy of the human, anterior cataract capsule]. / Licht- und Elektronenmikroskopie der humanen, anterioren Kataraktkapsel.

Forty-three anterior lens capsules and epithelium from cataract patients extracted during extracapsular cataract surgery were examined by light microscopy and morphometry. An additional 15 lens capsules were examined by transmission electron microscopy. Morphometric examination revealed a positive correlation between age and the lens capsule thickness of 0.08 micron/year. The medium lens-capsule thickness of a 65-year-old human being was 8.65 microns. Light microscopy of cataractous anterior lens capsule and epithelium demonstrated proliferative changes with a multilamellar arrangement of the lens epithelial cells and an increase in the pleomorphic appearance of the cell and nucleus. Examination of the lens capsule revealed intracapsular foamy and vacuolic deposits with a localized splitting of the lens capsule. Transmission electromicroscopy established certain aspects of the lens capsule and epithelium. We found intracytoplasmatic single cilia and fibrillar intracytoplasmatic structures, with a diameter of 12-20 nm arranged in a pseudocrystalline fashion. The anterior lens capsule demonstrated similarly localized deviations from the normal homogeneous structure of type IV collagen, resulting in intracapsular deposition of fibrillar material. These observations suggest that cataractogenesis is associated with ultrastructural metaplastic and degenerative alteration of the lens epithelium and capsule.

[Familial occurence of congenital short bowel (author's transl)]. / Familiäres Vorkommen des angeborenen Kurzdarmes.

We report the clinical and post-mortem findings of an infant with inborn short bowel. One sibling died because of the same malformation. The parents are cousins. This malformation is combined with malrotation, often with pylorus-stenosis too, and can cause an intestinal obstruction syndrome. All presently known cases in the pertinent literature are summarized. The occurence of familial cases suggest a rezessive autosomal disease.

[Perfluorochemicals as artificial blood. problems and actual development (author's transl)]. / Fluorocarbone als Erythrozytenersatz Bemerkungen zu Problematik und aktuellem Stand.

Perfluorochemical-type blood substitutes are excellent carriers of gases such as O2, CO2, CO, N2. These chemical compounds are insoluble in water and have an extreme chemical and biological inertness. They can be prepared as pyrogen-free sterilisable emulsions. In the last 10 years improvements in emulsion techniques and the results of experimental research work in several laboratories aroused increasing interest in fluorocarbons in the medical and biological field. Beside the treatment of severe loss of blood, numerous further potential uses of these substitutes have been described. Further improvements and studies are needed, especially concerning the storage-phenomenon in the reticulohistiocytic system and also the problems linked with the absence or reduction of the clotting system. The existing literature on this subject seems to justify an optimistic view of fluorocarbons as promising blood substitutes.