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Biomedical subjects

J Berges

Publications and source records attributed to J Berges.

At least 19 recordsLinked to original sources
PubMed2000

Gapless color superconductivity

We present the dispersion relations for quasiparticle excitations about the color-flavor locked ground state of QCD at high baryon density. In the presence of condensates which pair light and strange quarks there need not be an energy gap in the quasiparticle spectrum. This raises the possibility of gapless color superconductivity, with a Meissner effect but no minimum excitation energy. Analysis within a toy model suggests that gapless color superconductivity may occur only as a metastable phase.

Journal Article↗
PubMed1993

Sodium fluoride therapy.

As a medical treatment for otospongiosis-otosclerosis, sodium fluoride influences the underlying bony changes in the labyrinth so as to arrest or prevent the onset of hearing loss. Sodium fluoride is an enzyme inhibitor and reduces osteoclastic bone resorption and, if the dosage is more than 60 mg a day, may rebuild pseudohaversian bone.

Administration, Oral↗
PubMed1989

Etiology of otospongiotic sensorineural losses.

The etiology of otospongiotic-otosclerotic disease is enzymatic; the proteolytic enzymes released by the otospongiotic-otosclerotic foci damage the inner ear and are also the basis of the bony rebuilding of the OW niche leading to stapedial fixation. The trigger may be an autoimmune process due to the reaction of the enchondral otic capsule against the embryonic cartilaginous remnants, genetically determined to be located in the otic capsule and mainly in the fissula antefenestram.

Antibody Formation↗
PubMed1987

Structural and chemical characterization of isolated centrosomes.

A procedure adapted from that described by Mitchison and Kirschner [Nature 312:232-237, 1984] was used to isolate centrosomes from human lymphoid cells. High yields of homogeneous centrosomes (60% of the theoretical total, assuming one centrosome per cell) were obtained. Centrosomes were isolated as pairs of centrioles, plus their associated pericentriolar material. Ultrastructural investigation revealed: 1) a link between both centrioles in a centrosome formed by the gathering in of a unique bundle of thin filaments surrounding each centriole; 2) a stereotypic organization of the pericentriolar material, including a rim of constant width at the proximal end of each centriole and a disc of nine satellite arms organized according to a ninefold symmetry at the distal end and; 3) an axial hub in the lumen of each centriole at the distal end surrounded by some ill-defined material. The total protein content was 2 to 3 X 10(-2) pg per isolated centrosome, a figure that suggests that the preparations were close to homogeneity. The protein composition was complex but specific, showing proteins ranging from 180 to 300 kD, one prominent band at 130 kD, and a group of proteins between 50 and 65 kD. Actin was also present in centrosome preparations. Functional studies demonstrated that the isolated centrosomes were competent to nucleate microtubules in vitro from purified tubulin in conditions in which spontaneous assembly could not occur. They were also very effective at inducing cleavage when microinjected into unfertilized Xenopus eggs.

Animals↗
PubMed1986

Identification of centrosomal proteins in a human lymphoblastic cell line.

Highly enriched preparations of centrosomes from human T-lymphoblasts KE 37 were analyzed for their protein content. The specific pattern of polypeptides was characterized by an abundant subset of high mol. wt proteins and a major group of proteins with mol. wt ranging from 50 to 65 kd. Several immunoreactive proteins were identified, using a rabbit serum spontaneously reacting with human centrosomes. They include a family of high mol. wt ranging from 180 to 250 kd, a 130-kd protein and a 60-65 kd doublet. These antigens have the following properties: they are localized within the pericentriolar material; their abundance, as judged by centrosome labelling, changes significantly during the cell cycle, the maximum being observed at the pole of the metaphasic spindle; in Taxol-treated cells where the centrosome is no longer acting as a nucleating center, they redistribute at one end of the microtubule arrays in both mitotic and interphasic cells, as expected for nucleating, or capping, proteins. All these properties are compatible with their involvement in microtubule nucleation.

Antibodies↗
PubMed1982

The enzymatic mechanism of the otospongiotic disease and NaF action on the enzymatic balance.

Extensive research on enzymes led to the discovery of the innermost mechanism of the otospongiotic disease. The authors present the results of multiple correlations made from February 1976 to September 1980 on 648 samples of perilymph taken during stapedectomies performed on otosclerotic patients. We studied microdosages of three selected enzymes--trypsin, alpha 1 antitrypsin, and alpha 2 macroglobulin--in each of the samples and their relationship with cochlear deterioration expressed in dBs of bone conduction decrease in pure-tone audiometry testing. This study allowed us a better knowledge of the enzymatic mechanism of the otospongiotic disease, based on the previously reported trypsin-alpha 1 antitrypsin balance, but in which alpha 2 macroglobulin appears to play a role as essential as that of alpha 1 antitrypsin. This enzymatic mechanism explains NaF efficiency, which is due in fact to a double action: not only direct trypsin inhibition, but also an overall reduction in enzymatic values in the perilymph of otospongiotic/otosclerotic patients. Current studies could lead to the possibility of future NaF replacement by proteinase inhibitors either of microbial origin, under study by Japanese researchers, or even of synthetic origin, which should be investigated. In fact, the role of NaF therapy could already be taken over by diphosphonates currently under study.

Audiometry, Pure-Tone↗
PubMed1981

[Enzymatic mechanism of otosclerosis. Action of NaF].

The authors present the conclusions they reached after more than four years of multiple correlations made from february 1976 to september 1980. 648 perilymph samples were selected from a total number of 811 samples taken during stapedectomies on otosclerotic patients. These multiple correlations were based on micro-dosages of three selected enzymes (trypsin-alpha 1 antitrypsin and alpha 2 macroglobulin, the fourth cathepsin B having not been found, even in perilymph pools) in each of the selected samples, and on their relationship with the cochlear deterioration expressed in dBs of B.C. decrease and in audiometric stages corrected with reference to the patients' age. This study leads to an enzymatic mechanism, based on the previously reported trypsin-alpha 1 antitrypsin balance, but in which alpha 2 macroglobulin appears to play as essential a role as that of alpha 1 A. This enzymatic mechanism explains NaF efficiency, due in fact to a double action, not only to direct trypsin inhibition, but also to an overall reduction in enzymatic levels in the perilymph of otosclerotic patients. The authors conclude by suggesting the possibility of future NaF replacement by proteinase inhibitors, either of microbial origin currently under study by Japanese researchers, or even of synthetic origin.

Adult↗