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Biomedical subjects

J Frey

Publications and source records attributed to J Frey.

At least 253 records · Page 14Linked to original sources
PubMed1984

Induction of surface IgG receptors in cytomegalovirus-infected human fibroblasts.

Binding studies on diploid human fibroblasts with human immunoglobulin G (IgG) demonstrate the existence of a specific receptor for this class of immunoglobulin. The receptor preferentially binds aggregated human IgG and recognizes these complexes via the Fc portion of the molecule. Cytomegalovirus infection of diploid human fibroblasts results in a more than 100-fold increase in the number of IgG-receptors present on the cell surface. The binding of aggregated IgG by these newly expressed receptors exhibits the characteristics of the binding mediated by the receptors detectable in uninfected cells.

Binding, Competitive↗
PubMed1984

Binding and uptake of rabbit IgG complexes by diploid fibroblasts via plasma membrane Fc receptors.

The existence of IgG receptors on the plasma membrane of diploid human fibroblasts is demonstrated. The receptors specifically bind heat-aggregated rabbit IgG as well as rabbit IgG within antigen-antibody complexes. Monomeric rabbit IgG were only poor ligands of the receptor. Competition experiments with Fab and Fc fragments of IgG revealed that the receptor specifically recognizes the Fc domain of the IgG molecule. Heat-aggregated IgG or antigen-antibody IgG complexes are specifically bound to the receptors, endocytosed and subsequently degraded. The receptors do not seem to be recycled because protein synthesis is a prerequisite for further cycles of endocytosis.

Biological Transport↗
PubMed1984

A family/systems approach to illness-maintaining behaviors in chronically ill adolescents.

A distressingly significant number of chronic, seriously ill adolescents demonstrate poor medical management of their illnesses through "illness-maintaining behaviors." These behaviors are defined in this article as any action that compromises chronically ill adolescents' care and prevents them from functioning optimally. Current conceptualizations of illness-maintaining behaviors offer explanations that view these behaviors as individually focused, using either psychodynamic or behavioral models. This article, however, presents a family systems model of illness-maintaining behaviors. A therapeutic framework leading to specific intervention strategies is also developed.

Adolescent↗
PubMed1984

Measurement of changes in amino acids related to total collagen in fibrotic human liver.

In the liver, total collagen accumulation during the fibrotic or cirrhotic process was measured using a methodology based on the determination of collagen amino acids in liver biopsies from adults with alcoholic liver diseases or children with biliary atresia. The results obtained with this methodology were compared to histopathological findings. Thus, it was shown that generally the severity of hepatic injury was dependent on collagen accumulation. In biliary atresia, collagen accumulation increased with the children's age despite reconstructive surgery and restoration of biliary flow.

Adult↗
PubMed1984

Consequences of diabetes mellitus or liver cirrhosis on total collagen in human skin biopsies.

In this work, we studied the changes in human skin collagen occurring in diabetes mellitus and liver cirrhosis. The original methodology, based on the determination of the amino acids proline, 4-hydroxyproline, hydroxylysine, glycine and alanine, allowed us to reveal in skin a change in collagen in diabetes mellitus but none in liver cirrhosis. This biochemical evidence was correlated to the histological investigation. Moreover, diabetes mellitus did not involve any changes in hydroxylation of polypeptidic lysine. This latter observation was in accordance with the accumulation of normal collagen regarding amino acid composition only, and the results suggest a preferential accumulation of collagen type III in skin, in diabetes mellitus.

Adult↗
PubMed1983

[Transcapillary diffusion of Na-fluorescein in skin areas of the dorsum of the foot in juvenile diabetics].

Fluorescence videomicroscopy after intravenous injection of Na-fluorescein serves to quantitate dye diffusion out of single capillaries or capillary groups in an almost atraumatic manner [2, 4, 6, 8, 9]. In 14 young patients with a mean disease duration of 10 years and in 16 healthy controls, fluorescent light intensity was measured continuously during one hour at the dorsum of the foot by a videodensitometer covering an average of 68 capillaries. 1 second and 5 minutes after first appearance of the dye in the foot skin, the amount of the tracer detected in the area of measurement was significantly increased in the diabetics (p less than 0.05-0.001). At 1 minute, for example, mean fluorescent light intensity reached 47.2 +/- 18.1% of the maximal individual intensity and in the normals only 29.3 +/- 10.8% (p less than 0.01). In the patients the capillaroscopic image was characterized by early blurring, whereas the pericapillary halo of the controls contained more dye than the more remote interstitial space and remained well delineated for a much longer time. The new technique offers the possibility of studying transcapillary diffusion as an expression of microangiopathy in different groups of diabetic patients, and of following the effect of therapeutic regimens.

Adult↗
PubMed1983

Isolation and renaturation of alpha 2-macroglobulin receptor from diploid human fibroblasts.

alpha 2-Macroglobulin receptor was extracted from human diploid fibroblasts and purified by affinity chromatography in a single step. The receptor had mol.wt. 125 000 after sodium dodecyl sulphate (SDS)/polyacrylamide-gel electrophoresis. The isolated receptor was separated by SDS/polyacrylamide-gel electrophoresis, transferred on to nitrocellulose sheets and subsequently renatured, as shown by a specific binding test, by incubation with Nonidet P40.

Chromatography, Affinity↗
PubMed1983

In-vitro responses to ascorbate and manganese in fibroblasts from a patient with prolidase deficiency and iminodipeptiduria: cell growth, prolidase activity and collagen metabolism.

After successful ascorbate and manganese treatment of a female patient with prolidase deficiency and iminodipeptiduria, we attempted to explain the mechanism of action of these drugs in vitro, using them preferentially on skin fibroblasts. Since in vivo, ascorbate and manganese seemed to be responsible for both biochemical and clinical improvement, they were also expected to activate prolidase activity in vitro. Cell growth and prolidase activity were accordingly observed in fibroblast cultures supplemented with these compounds. It seemed that only ascorbate accounted for the successful in vivo response. To understand the mechanism involved, we studied collagen metabolism and found a decreased proline pool, a massive increase of rapidly degraded collagen and moderate enhancement of type III collagen and type I trimer in the patient's fibroblasts. We believe that ascorbate allowed the prolidase-deficient cells to maintain a normal collagen pool by increasing collagen synthesis. Both the massive increase in cell growth in response to ascorbate and the bad response as regards the quality of the collagen produced confirm the secondary nature of this mechanism. However, the relationship between accelerated collagen catabolism and prolidase deficiency remains unclear.

Adult↗
PubMed1983

Stable cosmid vectors that enable the introduction of cloned fragments into a wide range of gram-negative bacteria.

A cosmid cloning system has been developed which is useful for the construction of genomic libraries and the introduction of clones into a broad range of bacterial species. The cosmids pMMB33 and pMMB34 allow selective cloning into their unique BamHI site of 36-kb DNA fragments generated by BamHI, Sau3A and MboI partial digestion. This selective cloning is achieved by a strategy that avoids formation of polycosmids without a dephosphorylation step. It uses two unique recognition sites within the vectors for endoncleases that generate blunt-ended DNA fragments for the preparation of left and right cosmid "arms". An alternative method that uses the unique EcoRI and SstI sites and dephosphorylation of the cosmid arms prior to BamHI digestion is also outlined and discussed. The DNA is first cloned with either vector into a rec- E. coli strain, where clones can be maintained stably, and can then be introduced by mobilization into a wide range of Gram-negative species to permit the study of gene expression and complementation. Because mobilization is much more efficient than transformation, the vector has the advantage that it can be transferred between bacterial species that specify different restriction systems, where transformation appears to be inefficient. The vectors have been used to generate gene libraries from the chromosomal DNA of several Pseudomonas and a Thiobacillus species. The genes specifying myo-inositol transport from Pseudomonas strain JD34 have been cloned with this system.

Cloning, Molecular↗
PubMed1983

Replication control mutations of plasmid R6-5 and their effects on interactions of the RNA-I control element with its target.

Nine high copy number mutations of plasmid R6-5, representing five phenotypically distinct groups, have been identified by DNA sequencing. In each mutant plasmid examined, a single nucleotide change was found. The effects of the mutations on possible gene products, and DNA-RNA secondary structure, were analyzed and compared with the observed phenotypes. The results of this study exclude the possibility that the primary plasmid replication control element, the product of the copA gene, is a polypeptide, and they are consistent with a model of plasmid replication control by the copA product which has the following features: (i) RNA-I, a short untranslated RNA molecule, is the product of the copA gene and regulates the frequency of initiation of plasmid replication, (ii) the hexanucleotide single-strand loop of the major hairpin of RNA-I is its active site, (iii) this active site functions by base pair interactions with its "target," its DNA template strand, or its complementary sequence on RNA-II, a transcript of opposite polarity that is the message of the repA gene, and (iv) the sequence and size of the loop, and the stability of the stem of the hairpin, are all critical factors that govern the functioning of RNA-I.

Base Sequence↗
PubMed1983

Reversal of changes in lipoprotein A and lipoprotein B cholesterol during and for a year after a detoxication treatment program in chronic alcoholism.

We studied the individual and occasional changes in lipid metabolism induced by chronic alcohol abuse. In addition, the influence of a detoxication treatment program on the evolutionary changes in some serum lipidic components was studied for a one-year period. Before this program, total cholesterol was above normal, with high values for LP-A cholesterol, whereas for some patients LP-B cholesterol was increased. After the program, there was an increase in total cholesterol, LP-B cholesterol, and apolipoprotein B, with a decrease in LP-A cholesterol. These evolutionary changes continued during the one-year period after the end of the inpatient program.

Adult↗
PubMed1983

Evolutionary changes in acute-phase proteins in alcoholic hepatocellular diseases.

We studied the pattern of acute-phase proteins (orosomucoid, C-reactive protein, and haptoglobin) in hepatocellular deficiency due to chronic alcohol consumption, characterized by a decrease in serum transferrin concentration. We found that their patterns could vary independently of hepatocellular deficiency, but depend on the progression of hepatic disease. The most useful protein for discriminating the stage of inflammatory reaction is orosomucoid. In moderate hepatocellular deficiency, acute-phase proteins are increased independently of the decrease in transferrin, whereas in severe hepatocellular deficiency the acute-phase proteins are also decreased. Thus, it is possible to distinguish the two stages of hepatocellular deficiency by following changes in the concentration of orosomucoid.

Acute Disease↗
PubMed1982

Patterns of diffusion through skin capillaries in patients with long-term diabetes.

We used intravital fluorescence videomicroscopy to study the pattern of transcapillary and interstitial diffusion in the nail folds of 13 patients with long-term diabetes and of 12 healthy controls. In both groups intravenously injected sodium fluorescein left the intravascular compartment. Its distribution in the pericapillary space and in the remote parts of the interstitial space was measured on single frames of the television tape by videodensitometers that are sensitive to intensities of fluorescent light. In the diabetics the dye passed both physiologic diffusion barriers--the capillary wall and the pericapillary space--in significantly increased amounts (P less than 0.01). The enhanced penetration of the tracer into the remote area caused an early homogeneous, milky blurring of the capillary image, whereas in the controls the pericapillary space remained clearly delineated for as long as 40 to 50 minutes after the appearance of the dye. The altered pattern of diffusion could be explained by increased permeability of the diffusion barriers, or, alternatively, by either changes of the mobility of the dye due to binding of the dye by intravascular or interstitial proteins or abnormal hemodynamics in the microvascular circulation. This technique provides a quantitative, noninvasive method of studying the natural history of diabetic microangiopathy.

Adult↗
PubMed1981

The initiation of chromosome replication in a dnaAts46 and a dnaA+ strain at various temperatures.

The regulation of chromosome replication initiation was studied at various temperatures with an E. coli dnaA46 strain and its dnaA+ parent. We find that, in both strains, the "initiation mass" varies depending upon growth temperature while the replication time remains constant relative to the cell doubling time. In the permissive temperature range, the initiation mass of the dnaA46 mutant strain is larger by a constant factor than that for a dnaA+ strain. We conclude that, even at temperatures permissive for growth of the dnaA46 strain, the activity of the dnaA46 product is lower than that of the wild-type protein. The dnaA gene product, therefore, plays an important role in regulating initiation.

DNA Replication↗