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Biomedical subjects

U Gross

Publications and source records attributed to U Gross.

At least 181 records · Page 10Linked to original sources
PubMed1986

Immunochemical analysis of plasmid-encoded proteins released by enteropathogenic Yersinia sp. grown in calcium-deficient media.

Enteropathogenic Yersinia sp. releases plasmid-associated proteins of low molecular mass (26-67 kilodaltons) at 37 degrees C. In this study, the optimum conditions for the release of proteins were assessed and the released proteins (RPs) were analyzed for the manner of release, immunochemical characteristics, and the location of the genes necessary for their synthesis. Protein release was strongly enhanced when growth media were markedly depleted of calcium ions by precipitation with oxalate or chelation with EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid]. RP yields were greatest when Yersinia spp. were in the exponential growth phase. The RPs appeared to be released from the Yersinia spp. by secretion rather than by pinching off of membrane vesicles, because the RPs did not sediment during high-speed centrifugation nor were they contaminated to any significant degree with lipopolysaccharide. Moreover, immunoblot analysis revealed only traces of protein species related to RPs within the outer membranes of plasmid-positive Yersinia spp. grown at 37 degrees C under calcium-restricted conditions. Immunoblot studies also showed that the RPs of Y. enterocolitica serotypes O:3, O:8, and O:9 and the RP of Y. pseudotuberculosis serotype I are highly cross-reactive. Finally, the immunoprecipitates of the products of minicells which harbor Yersinia plasmids were used to demonstrate that at least three proteins immunochemically related to the released fraction were plasmid encoded. These results suggest that at least three of the RPs may be related to or identical with previously described plasmid-encoded Yersinia outer membrane proteins.

Bacterial Proteins↗
PubMed1985

[Specific gastrointestinal manifestations of a generalized cytomegalovirus infection in a patient with acquired immune deficiency syndrome].

In a patient with AIDS, severe cytomegalovirus (CMV) infection dominated with gastro-intestinal and retinal involvement. The gastro-intestinal signs--diarrhoea and recurrent vomiting--correlated with the destruction of the tunica muscularis of the digestive tract seen at post-mortem. The CMV retinitis caused an almost complete loss of sight, the consequence of extensive destruction of the retina. In addition to the generalized CMV infection and disseminated Kaposi's sarcoma, which also involved the gastro-intestinal tract and caused discrete histopathological changes, post-mortem examination revealed a malignant lymphoma of the brain.

Acquired Immunodeficiency Syndrome↗
PubMed1985

The interface of various glasses and glass ceramics with a bony implantation bed.

Basing on histomorphological evaluations and morphometrical quantifications in a standardized model experiment, a comparison is made between the reactions of skeletal tissues to various glasses, glass-ceramics and enamels. On the surface of these so-called reactive biomaterials either a direct bonding to mineralized bone or also different amounts of osteoid or chondroid tissue formation can be observed, depending on the composition of the material. It is shown that the solubility of the glasses cannot directly be related to the reactivity and the resulting bone bonding; bone binds only to glasses with a controlled release of constituents and which exhibit a seam of extracellular matrix on their surface, in which normal primary mineralization can occur; the release of constituents such as Al2O3, Ta2O5, ZrO2, or phosphates from the material can inhibit this normal mineralization and the transformation of chondroid tissue to bone; if connective tissue instead of bone is present at the interface (either primarily or after bone remodelling), the dissolution (or corrosion) of the material may be no longer controllable, and the tissue reacts with a continuous inflammatory response to the corrosion products.

Animals↗
PubMed1983

Volume regulation and metabolism of suspended C6 glioma cells: an in vitro model to study cytotoxic brain edema.

The in vitro model presented provides an approach to study the nature of cell volume control as well as of swelling mechanisms under pathophysiological conditions. Pertinent parameters of cell volume control can be analyzed in isolation due to a virtually infinite extracellular environment precluding secondary effects of the suspended cells. Exposure of C6 glial cells to hypotonic medium was investigated as a model to study fundamental aspects of cell volume control. In confirmation of studies on other cell types glial cells suspended in hypotonic medium recover cell volume after transient swelling. Normalization of cell volume is associated with stimulation of respiration. Moreover, normalization of cell volume in hypotonic medium can be pharmacologically influenced. Addition of naftidrofuryl which enhances cellular O2-consumption led to acceleration of cell volume recovery. On the other hand, inhibition of Na+-K+-ATPase by ouabain did not prevent regulatory volume decrease ruling out a major role of the Na+-transport enzyme in this process. Contrary to hypotonic suspension, hypertonic exposure did not result in volume regulation during an observation period of 3 h. However, this may not necessarily exclude a capability of cell volume to normalize in hypertonic conditions as observed in vivo. Volume control of glial cells in abnormal osmotic medium may--on a cellular basis--reflect fundamental adaptive processes of central nervous tissue. Knowledge of the physiological and biochemical basis of cell volume control is not only of scientific interest but also of therapeutical significance in patients suffering from cytotoxic brain edema.

Brain Edema↗
PubMed1983

Does piezoceramic influence avian bone formation in the early postoperative phase?

Polarized and depolarized blocks of a piezoceramic composed of Pb (ZrTi)O3 are implanted in the diaphysis of the metatarsus of cocks. 15, 34, 55 and 84 days postoperatively, the implantation bed is histomorphologically examined, and the percentage of bone, osteoid and chondroid at the interface of the base and top area of the implants is morphometrically determined. The same types and the same amount of tissue develop with the same dynamics in the bed of polarized and depolarized piezoceramic. Therefore polarized piezoceramic has no positive influence on bone formation in the early postoperative phase.

Animals↗
PubMed1982

[Post-traumatic ankylosis (pathomorphologic aspects)].

At first, the symptoms observed in case of a post-traumatic ankylosis are defined. Then the possible reactions of tissue to a trauma to the joint or the joint region which may lead to an ankylosis are discussed with regard to general pathologic points of view. Some special pathologic aspects of lesions and their consequences are shown for the shoulder joint, the elbow joint, and the knee joint. Finally, several examples are given in order to illustrate possible histomorphologic symptoms leading to a post-traumatic ankylosis.

Adult↗
PubMed1981

The ultrastructure of the interface between a glass ceramic and bone.

The interface of alkali-poor glass ceramic implanted in femora of male Sprague-Dawley rats shows soft tissue, chondroid, osteoid, and bone in connection with the implant. The ultrastructure of the interface with soft tissue mainly exhibits a corrosion process, during which the dissolution of the crystalline phase of the glass ceramic precedes the dissolution of the glassy phase. Macrophages are involved in this process phagocytosing debris of the glassy phase and removing as well as dissolving the remainders of the glass ceramic. Under circumstances not yet fully understood, the corrosion stops, and ground substance like material is deposited, which can be, at least partially, mineralized. After the disappearance of macrophages, chondroblasts, and/or osteoblasts lay down collagen fibrils and ground substance in which matrix vesicles are discernible, representing initial foci of mineralization. Areas with bone connection display collagen fibers and deposits of apatite crystals in close relationship to the bulk glass ceramic as well as small particles mainly derived from the glassy phase of the implant, providing the micromorphological substrate for the shearing and tensile strength of the interface between glass ceramic and bone.

Animals↗
PubMed1981

Primary mineralization and extracellular matrix vesicles in rat bone after administration of glass-ceramic implants.

Glass-ceramic implants were administered into cavities prepared in rat femoral shaft. Electron microscope examination revealed formation of collagenous rich matrix in the implant-bone interface. Features typical to primary mineralization as well as bone and implant resorption were present in the interface. Primary mineralization was characterized by the occurrence of active forming cells, extracellular matrix vesicles and calcifying calcospheritic structures. Intensive primary mineralization in association with the implants indicates that glass-ceramic may be stimulative to ossification, allowing favorable tissue-implant relationship.

Animals↗
PubMed1980

[Tissue substitution in experimental oral surgery from a general viewpoint of pathology].

In experimental maxillo-facial surgery the replacement of large pieces of bone as a substitute for tissue is of special practical interest. The various possibilities of the interaction and connection between transplants and alloplastic implants in the surgical bed especially in bone are demonstrated under the aspects of general pathology and some proposals are given for a more precise terminology in this field. The application of dynamic load to implants is shown to be a leading factor for the development of the special biotechnical structure of a neoperiodontal ligament during the regeneration of tissue in the case of the dental rod implant. Stimulation is given for the improvement and development of better allopastic implant materials yielding to a durable connection between bone and implant.

Animals↗