Expression of glutathione S-transferase T1 (GSTT1) in human brain tumours.

Glutathione S-transferases (GSTs) play a central role in a number of metabolic processes. Glutathione S-transferase T1 (GSTT1) is a polymorphic cytosolic enzyme and a member of the theta class of GSTs. Typical substrates for GSTT1 are industrial compounds, such as dichloromethane and ethylene oxide.

Hematopoietic cells are a source of nidogen-1 and nidogen-2 during mouse liver development.

Nidogen-1 and -2 are key components of basement membranes (BMs). Despite the presence of nidogen molecules in the parenchyma of the developing liver, no BMs are formed therein. This suggests that, in the liver, nidogens may also have functions other than BM formation.

Localization of the sulfate/anion exchanger in the rat liver.

Although the sulfate/anion transporter (sat-1; SLC26A1) was isolated from a rat liver cDNA library by expression cloning, localization of sat-1 within the liver and its contribution to the transport of sulfate and organo sulfates have remained unresolved. In situ hybridization and immunohistochemical studies were undertaken to demonstrate the localization of sat-1 in liver tissue. RT-PCR studies on isolated hepatocytes and liver endothelial and stellate cells in culture were performed to test for the presence of sat-1 in these cells.

Localization of Apaf1 gene expression in the early development of the mouse by means of in situ reverse transcriptase-polymerase chain reaction.

Apoptosis is an essential ubiquitous process that controls the duration of the life span of cells, thus playing a crucial role in morphogenetic, histogenetic, and phylogenetic developmental processes. Apaf1 (apoptosis protease activating factor 1) is one of the central mediators of the intrinsic apoptotic pathway and a part of the apoptosome, which activates procaspase-3 and promotes cell death. Gene knockout of Apaf1 in mice leads to late embryonic lethality with malformations such as the persistence of interdigital webs and hyperplasia of brain and retina.

Collagen types XII and XIV are present in basement membrane zones during human embryonic development.

The collagens constitute a large group of proteins in the extracellular matrix that can be divided into several distinct families. Collagen types XII and XIV belong to a subgroup of non-fibrillar-collagens termed (fibril-associated collagens with interrupted triple-helices) (FACIT) and may be involved in basement membrane regulation providing specific molecular bridges between fibrils and other matrix components. However, the tissue distribution of the two proteins during human embryogenesis is still unclear.

Expression of collagen type I and type II in consecutive stages of human osteoarthritis.

In normal hyaline cartilage the predominant collagen type is collagen type II along with its associated collagens, for example, types IX and XI, produced by normal chondrocytes. In contrast, investigations have demonstrated that in vitro a switch from collagen type II to collagen type I occurs. Some authors have detected collagen type I in osteoarthritic cartilage also in vivo, especially in late stages of osteoarthritis, while others have not.

Ultrastructural localization of integrin subunits alpha3 and alpha6 in capillarized sinusoids of the human cirrhotic liver.

Normal liver sinusoids are not lined by a basement membrane (BM). In contrast, in the course of development of liver cirrhosis, a structured BM is formed de novo in the space of Disse. This BM contributes to the inhibition of the metabolic function of the liver but the pathogenic background of the formation of this perisinusoidal BM is still unclear.

The collagen type XVIII endostatin domain is co-localized with perlecan in basement membranes in vivo.

The C-terminal globular endostatin domain of collagen type XVIII is anti-angiogenic in a variety of experimental tumor models, and clinical trials to test it as an anti-tumor agent are already under way. In contrast, many of its cell biological properties are still unknown. We systematically localized the mRNA of collagen type XVIII with the help of in situ hybridization (ISH) and detected it in epithelial and mesenchymal cells of almost all organ systems throughout mouse development.

Fibrillin-1 and fibrillin-2 in human embryonic and early fetal development.

The extracellular glycoproteins fibrillin-1 and fibrillin-2 are major components of connective tissue microfibrils. Mutations in the fibrillin-1 and fibrillin-2 genes are responsible for the phenotypical manifestations of Marfan syndrome and congenital contractural arachnodactyly respectively, which emphasizes their essential roles in developmental processes of various tissues. Consistent with this last notion, organ culture experiments have indirectly suggested morphogenic roles for fibrillins in lung and kidney development.

In situ-RT-PCR and immunohistochemistry for the localisation of the mRNA of the alpha 3 chain of laminin and laminin-5 during human organogenesis.

Laminin-5 is known to be an integral part of the hemidesmosome and therefore responsible for the integrity of the connection of the epithelium to the basement membrane. This is also an important mechanism during embryonic development, as documented by studies in mice. In an attempt to elucidate its implication for human development we localised the mRNA of the alpha3 chain of laminin with the help of in situ RT-PCR, and the laminin-5 protein immunohistochemically.

Nidogen-1 and nidogen-2 are found in basement membranes during human embryonic development.

The recently identified nidogen-2 is a matrix protein showing homology to the well-known basement membrane molecule nidogen-1. Nidogen-1 might well serve as a link between laminin-1 and collagen type IV and thus stabilise certain basement membranes in vivo and play a major role in embryogenesis. However, the exact tissue distribution of nidogen-1 and nidogen-2 during human embryogenesis is still unclear.

The small proteoglycans decorin and biglycan in human articular cartilage of late-stage osteoarthritis.

Objective: Disturbances in proteoglycan metabolism of hyaline cartilage play an essential role in the pathology of degenerative joint disease. We investigated the relation between transcript expression, protein synthesis and the ultrastructural localization of the matrix-organizing proteoglycans decorin and biglycan within intra- and extracellular compartments of late-stage osteoarthritic human articular cartilage.

Methods: Human cartilage samples of a macroscopically intact area, the adjoining area and an area of the main defect from knee joints of 10 patients with late stage osteoarthritis were investigated.

Increase in band 3 density and aggregation in hereditary spherocytosis.

Purpose: Red cells in hereditary spherocytosis are characterized by a reduced surface area/volume ratio. The mechanisms leading to the loss of membrane material and subsequent elimination of the cells have still not been clarified. It was the aim of the present study to analyze band 3 distribution in the red cell membrane and its putative role in red cell elimination.

Role of aquaporin-4 water channel in the development and integrity of the blood-brain barrier.

In this study, we have investigated the expression of aquaporin 4 during blood-brain barrier development in the optic tectum of chick embryos and newly hatched chicks, by means of western-blot, reverse transcriptase-polymerase chain reaction, immunohistochemistry, and freeze-fracture and high-resolution immunogold electron microscopy. In the optic tecta of day-14 embryos, western blot analysis revealed an approx. 30 kDa band, immunoreactive for aquaporin-4, which was increased in day-20 embryos and in chicks.

Aquaporin-4 deficiency in skeletal muscle and brain of dystrophic mdx mice.

We report a detailed study of AQP4 expression in the neuromuscular system of mdx mice. Immunocytochemical analysis performed by double immunostaining revealed that mdx mice manifest a progressive reduction in AQP4 at the sarcolemmal level of skeletal muscle fast fibers and that type IIB fibers are the first to manifest this reduction in AQP4 expression. No labeling was observed in the cytoplasm of muscle fibers, indicating that the reduction in sarcolemma staining is not associated with an intracellular compartmentalization of mistargeted protein.

Skin and hair follicle integrity is crucially dependent on beta 1 integrin expression on keratinocytes.

beta 1 integrins are ubiquitously expressed receptors that mediate cell-cell and cell-extracellular matrix interactions. To analyze the function of beta1 integrin in skin we generated mice with a keratinocyte-restricted deletion of the beta 1 integrin gene using the cre-loxP system. Mutant mice developed severe hair loss due to a reduced proliferation of hair matrix cells and severe hair follicle abnormalities.

Aquaporin-4-containing astrocytes sustain a temperature- and mercury-insensitive swelling in vitro.

In order to understand the molecular mechanism underlying astroglial swelling, we studied primary astrocyte cultures from newborn mouse and analyzed them for expression of functional water channels. Immunocytochemical analysis of mouse brain confirms the presence of AQP4 location in astrocytic endfeet with a polarized pattern, as found in rat. Using Southern blot PCR and Western blot analysis, we demonstrate that primary astrocyte cultures from mouse express the AQP4 water channel at both the RNA and protein levels.

Ultrastructural colocalization of nidogen-1 and nidogen-2 with laminin-1 in murine kidney basement membranes.

Nidogen-1, a key component of basement membranes, is considered to function as a link between laminin and collagen type IV networks. Recently a new member of the nidogen family, nidogen-2, has been characterized. Preliminary immunohistochemical data indicated that nidogen-1 and nidogen-2 show a similar tissue distribution at the light microscopic level.

Extensive glycosylation changes revealed by lectin histochemistry in morphologically normal prenatal tissues of the mouse mutant undulated (un/un).

Recently we observed that in human embryos and fetuses with a variety of malformations, not only malformed tissues, but also several non-malformed tissues displayed alterations in the glycosylation pattern. It was the aim of this work to investigate this more or less inexplicable phenomenon under experimental conditions. To this end, we studied a well known mouse model, the mouse mutant undulated, which has an exactly defined genetic defect (substitution in the pax-1 gene) leading to a localized malformation in the vertebral column.

Interferon beta-1a prevents the effects of lipopolysaccharide on embryonic brain microvessels.

By means of light and electron microscopy we have studied the effect of interferon beta-1a (IFNbeta-1a) in the optic tecta of 20-day-old chick embryos under normal conditions and after exposure to lipopolysaccharide (LPS) which mimics the blood-brain barrier (BBB) disruption in meningoencephalitis. Optic tecta were examined for: (i) ultrastructure by means of transmission electron microscopy; (ii) the immunohistochemical localization of HT7 antigen, a specific marker of differentiation of the brain microvessels; (iii) the brain microvessel permeability, by means of horseradish peroxidase (HRP) tracer; (iv) the expression of microvessel glycoconjugates, by means of lectin histochemistry, using Ricinus communis agglutinin-I (RCA-I), specific for beta-D-galactosyl moieties and Wheat Germ agglutinin (WGA) specific for sialyl and N-acetylglucosaminyl moieties. A morphometric evaluation of brain microvessel permeability and of glycoconjugate expression was also performed.

Nidogen-1. Expression and ultrastructural localization during the onset of mesoderm formation in the early mouse embryo.

Nidogen-1, a key component of basement membranes, is considered to function as a link between laminin and collagen Type IV networks and is expressed by mesenchymal cells during embryonic and fetal development. It is not clear which cells produce nidogen-1 in early developmental stages when no mesenchyme is present. We therefore localized nidogen-1 and its corresponding mRNA at the light and electron microscopic level in Day 7 mouse embryos during the onset of mesoderm formation by in situ hybridization, light microscopic immunostaining, and immunogold histochemistry.

Organization of the myotendinous junction is dependent on the presence of alpha7beta1 integrin.

The laminin receptor alpha7beta1 is enriched at the myotendinous junctions, and mice with a targeted inactivation of the alpha7 gene develop a form of muscular dystrophy that primarily affects this structure. By ultrastructural analysis of alpha7-deficient mice, in comparison with wild-type and mdx mice, we attempted to elucidate the role of alpha7 integrin for the integrity and function of the myotendinous junctions. Ultrastructurally, myotendinous junctions of alpha7-deficient myofibers lose their interdigitations and the myofilaments retract from the sarcolemmal membrane, whereas the lateral side of the myofibers remains morphologically normal.

Matrix metalloproteinases in early human liver development.

Matrix metalloproteinases (MMPs) regulate matrix deposition in tissues. Collagens I, III, and IV are involved in early human liver development. To establish whether MMPs specific for these collagens participate in early human liver development, we localized immunohistochemically MMP-1 and MMP-13 (for collagens I and III) and MMP-2 and MMP-7 (for collagen IV) in the early human liver anlage [6th-10th gestational week (GW)].

Developmental expression of ZO-1 antigen in the mouse blood-brain barrier.

Tight junction biogenesis during blood-brain barrier development (BBB) in mesencephalon microvessels of mouse embryos of day 9, foetuses of day 15 and 19 and new-born (2-day-old) mice was examined by light and electron microscopy, using monoclonal antibodies recognizing the tight junction peripheral membrane protein ZO-1. A faint spot-like staining began to be recognizable under the light microscope in day 15 vessels in which the endothelial cells showed isolated fusion points between the external plasma membrane leaflets under the electron microscope. A stronger labelling was present in microvessels of day 19 foetuses and new-born animals when the endothelial tight junction appeared completely differentiated.