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D F Hochstrasser

Publications and source records attributed to D F Hochstrasser.

At least 91 records · Page 5Linked to original sources
PubMed1994

Analysis of glycoproteins separated by two-dimensional gel electrophoresis using lectin blotting revealed by chemiluminescence.

The carbohydrate structures of blotted glycoproteins can be analyzed by probing with lectins. The objective of the present work was to optimize the lectin blotting of human plasma glycoproteins separated by two-dimensional gel electrophoresis and the detection by the sensitive chemiluminescence method. The proposed detection method was found to be ten times more sensitive than a standard colorimetric reaction. Furthermore, the generated signals are detected on a X-ray film and provide a permanent record. The method is also very reliable when compared to the colorimetric detection. The present procedure for glycoprotein analysis is particularly well suited for screening changes in glycosylation of proteins in biological samples.

Adamantane↗
PubMed1994

Two-dimensional polyacrylamide gel electrophoresis analysis of cryoglobulins and identification of an IgM-associated peptide.

The clonality of immunoglobulins (Igs) in cryoprecipitates (n = 41) was studied by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). Our series included 24 cryoglobulins characterized by immunofixation electrophoresis (IF), 12 'trace amount' cryoglobulins, defined by a protein content in the precipitate of less than 0.05 mg/ml of serum, and five cryoglobulins of undetermined protein composition by IF. 2-D PAGE analysis showed polyclonal IgG associated either with monoclonal Igs (type II cryoglobulins; n = 14) or with polyclonal IgM (type III cryoglobulins; n = 14). In ten cryoprecipitates (two 'trace amount' cryoglobulins as well as seven of 19 type II and as one of five type III cryoglobulins by IF) polyclonal IgG were associated with a mixture of polyclonal and monoclonal IgM. These cryoglobulins were tentatively named type II-III cryoglobulins. A monoclonal IgM was observed in one cryoprecipitate (type I cryoglobulins). Two cryoglobulins presented unexpected 2-D patterns, characterized by the presence of oligoclonal IgM, with trace amounts of Igs of different isotypes (tentatively named type II-III(variant) cryoglobulins). A peptide of 44 kDa with a pI of 5.45 was observed in all cryoglobulins containing IgM (n = 40). This peptide was also present in purified monoclonal or polyclonal IgM fractions. N-terminal microsequencing (12 amino acid residues) revealed that this IgM-associated peptide was an unknown protein. Our results highlight the role of 2-D PAGE as an aid in the analysis of cryoglobulins.

Amino Acid Sequence↗
PubMed1994

No evidence for protein modifications in fresh frozen plasma after photochemical treatment: an analysis by high-resolution two-dimensional electrophoresis.

To study if photochemical treatment of human plasma by methylene blue in combination with visible light induces protein alterations, we analysed by high-resolution two-dimensional gel electrophoresis (2-D PAGE) untreated and photochemically treated fresh frozen plasma collected by apheresis from the same donor (n = 8). Polypeptides were separated according to their charges by isoelectric focusing and to their sizes in polyacrylamide gels in presence of sodium and to their sizes in polyacrylamide gels in presence of sodium dodecyl sulphate, and visualized by silver staining. Despite their apparent complexity, protein maps of untreated plasma and photochemically treated fresh frozen plasma revealed identical spot patterns. Thus, photochemical treatment did not induce apparent protein pattern modifications.

Blood Proteins↗
PubMed1994

Two-dimensional electrophoretic study of normal colon mucosa and colorectal cancer.

Two-dimensional gel electrophoresis has been used to analyze polypeptide composition of specimens of human normal colon mucosa and colorectal carcinomas. Immobilized pH gradient in the first dimension improved the separation and enabled us to analyze proteins from whole tissue samples with high reproducibility. Polypeptides were separated within sigmoidal 3.5-10 pH gradient and range of mol. weight 15-200 KD. In global, protein patterns of normal and malignant tissue seemed to be close to each other. We attempted to combine two-dimensional electrophoretic separation with the immunoblotting technique using patient sera to identify possible tumor antigens. From a wealth of spots on silver stained protein maps of adjacent normal colon mucosa or tumor tissue, only few spots gave positive reaction. These spots might be classified into two groups: 1) common for normal colon mucosa and tumor, 2) specific for tumor tissue. The extent of patient's antibody reaction with antigens appeared to correspond to urinary neopterin level, an index of immune activation.

Adenocarcinoma↗
PubMed1994

A classification of one-dimensional electrophoresis gels using wave packet decomposition.

A classification of one-dimensional electrophoresis gels was achieved using a fast approximation of the Karhunen-Loève transformation. The algorithm was based on wave packet decomposition theory, using in particular quadrature mirror filters derived from orthogonal bases of wavelets. Bacterial proteins from two different species of staphylococci were separated by SDS-PAGE electrophoresis. The gel images were analyzed by computer and the protein bands were clustered, after an orthogonal projection onto a space of lower dimension, by standard statistical methods.

Algorithms↗
PubMed1994

The SWISS-2DPAGE database of two-dimensional polyacrylamide gel electrophoresis.

SWISS-2DPAGE is a database of proteins identified on two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), created and maintained at the University Hospital of Geneva in collaboration with the Department of Medical Biochemistry of Geneva University. The proteins have been identified on various 2-D PAGE reference maps by microsequencing, immunoblotting, gel comparison and amino acid composition.

Blotting, Western↗
PubMed1993

Human liver protein map: update 1993.

This publication updates the reference human liver protein map. By microsequencing, 27 spots or 34 polypeptide chains were identified. The most abundant polypeptides detected on the silver stained liver map were key elements in major hepatic biochemical pathways. The new polypeptides and previously known proteins are listed in a table and/or labeled on the protein map, thus providing the 1993 reference human liver SWISS-2DPAGE database. SWISS-2DPAGE and the SWISS-PROT protein sequence databases are closely linked together through the use of common accession numbers.

Amino Acid Sequence↗
PubMed1993

SWISS-2DPAGE: a database of two-dimensional gel electrophoresis images.

This publication presents the SWISS-2DPAGE database which gathers data on proteins identified on various two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) maps. Each SWISS-2DPAGE entry contains data on one protein, including mapping procedures, physiological and pathological data and bibliographical references, as well as several 2-D PAGE images showing the protein location. Links are also provided to other databases such as SWISS-PROT, EMBL, PROSITE and OMIM. The database has been set up on a server which may be accessed from any computer connected to the internet and it also makes it possible to display the theoretical location of proteins, the positions of which are not yet known on the 2-D PAGE.

Databases, Factual↗
PubMed1993

Two-dimensional electrophoresis as an aid in the analysis of the clonality of immunoglobulins.

In this paper, we summarize our five-year observation of two-dimensional polyacrylamide gel electrophoretic (2-D PAGE) analysis of immunoglobulin (Ig) light (L) chain patterns on serum/plasma and/or purified human Ig, and compare this technique with agarose electrophoresis and/or immunofixation examination. Polyclonal Ig L chains were seen as large "fuzzy" areas with several zones of high density. The majority (71%) of the monoclonal Ig L chains of monoclonal gammopathy detected by conventional electrophoresis appeared as a single large and well-defined spot on 2-D PAGE analysis, with the remaining appearing as multiple spots. The presence of oligoclonal Ig, reflected by multiple spots in 2-D PAGE, and several bands in immunofixation, was observed in 5 of 26 patients after allogeneic bone marrow transplantation and in 5 patients with tumors. In the majority (77%) of hypergammaglobulinemia, L chains appeared as a wide spread of small and well-defined spots in 2-D PAGE analysis. This pattern suggested oligoclonal Ig-secreting B cell clone expansion, and corresponding abnormalities were not detected with immunofixation. 2-D PAGE analysis also detected oligoclonal Ig expansions whereas conventional electrophoretic examination was normal in 10 additional patients after bone marrow transplantation, and in 6 of 10 immunocompetent patients with acute severe infections. Analysis of the Ig L chain pattern of a severe combined immune-deficient mouse populated with human peripheral blood leukocytes confirmed the skewed human Ig production in the model. In summary, 2-D PAGE appears to be a sensitive tool for the analysis of Ig diversity in various clinical situations.

Animals↗
PubMed1993

Colloidal carriers for intravenous drug targeting: plasma protein adsorption patterns on surface-modified latex particles evaluated by two-dimensional polyacrylamide gel electrophoresis.

Targeting to specific sites of the body via colloidal carriers is sought in order to reduce drug side effects. The adsorption of plasma proteins on intravenously injected particles is regarded as the key factor in explaining their organ distribution: total bound protein, or, more likely, the presence of specific proteins and their conformation, are expected to influence macrophage uptake. Polystyrene beads, 60 nm in diameter, were used as model carriers; their surface was differentially modified by adsorption of increasingly hydrophilic block copolymers, poloxamers 184, 188 and 407. After incubation in plasma, the patterns of protein adsorption onto coated beads were analyzed by high-resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The behavior of some representative proteins was monitored, including albumin, fibrinogen, IgG, factor B and the apolipoproteins, A-I, A-IV, C-III, E and J. The more hydrophobic the particles, the larger the total amount of bound protein. However, this correlation was not valid for all of the analyzed protein species, which proves that it is insufficient to look only at physicochemical data to predict organ distribution. On the contrary, it is essential to use 2-D PAGE to establish the correlation between adsorbed proteins and carrier behavior in vivo.

Adsorption↗
PubMed1993

Pattern variations of polyclonal and monoclonal immunoglobulins of different isotypes analyzed by high-resolution two-dimensional electrophoresis.

High-resolution two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used to analyze serum samples and purified immunoglobulins (Ig) obtained from "normal" individuals and from patients diagnosed with monoclonal gammopathies (MG) (n = 47; 5 IgA, 15 IgM, 15 IgG, 4 biclonal IgG, 1 IgD, 7 Bence Jones proteins). Polyclonal and monoclonal heavy (H) chains were located at different restricted gel positions according to their isotype. Monoclonal H chains appeared as sets of spots characterized by charge (pI) and size (M(r)) microheterogeneity. Most of the monoclonal gamma chains were not seen on the gels (12/15). Supplementary polypeptides of 45-48 kDa were detected in serum samples containing monoclonal IgM, but were not seen in MG of other isotypes. However, these polypeptides were not specifically associated with monoclonal IgM because they were also found on protein maps of purified polyclonal IgM. Polyclonal light (L) chains appeared as cloudy bands containing several zones of higher density, whereas monoclonal L chains were usually resolved as single sharp spots. In 6 samples, monoclonal L chains were not seen, and in 9 samples, they appeared as two or more spots, characterized by different pI and/or M(r). In one sample obtained from a patient with a biclonal gammopathy, the L chains were resolved as 4 different spots. Our results confirm that 2-D PAGE is an excellent tool to study Ig. Analysis of the L chain region of the gels was particularly informative. Several monoclonal L chains exhibited heterogeneous two-dimensional spot patterns, suggesting that "subtile" clonal mutations of B-cell lineage and/or posttranslational modifications were involved in their production.

Antibodies, Monoclonal↗
PubMed1993

Clonal imbalances of plasma/serum immunoglobulin production in infants.

To study the clonal events occurring during ontogeny of the humoral immune system, we evaluated plasma immunoglobulin (Ig) production in term newborns and young children by high-resolution two-dimensional gel electrophoresis. The clonality pattern of Ig light (L) chains from healthy newborns (n = 19) was similar to that observed on protein maps of their mothers or of normal adults (n > 100), that is, rare distinguishable small spots in a cloud-like large band of indiscrete Ig L chain spots (polyclonal pattern; maternal Igs). Analysis of plasma samples obtained from infants between 1 month and 5 years of age (n = 55) revealed discrete but evident alterations of the clonality of Ig production. Between the 2nd and 4th months of life, transient attenuation of the "polyclonal background" was observed in association with the appearance of an increasing number of well-resolved Ig L chain spots (corresponding to plasma Ig concentrations between 0.5 and 1 g/L per spot). This "restricted" clonal pattern was progressively less apparent on protein maps of infants older than 2 year and evolved towards a "normal" adult polyclonal pattern at the age of 5. These results suggest that the development of the B-cell clones is heterogeneous, either through limited outgrowth of precursor cells or through selective antigenic pressures.

Adult↗
PubMed1993

Determination of human alcohol dehydrogenase and acetaldehyde dehydrogenase genotypes by single strand conformation polymorphism in discontinuous buffer electrophoresis.

Under appropriate conditions single strand conformation polymorphism (SSCP) analysis of polymerase chain reaction (PCR) products allows the detection of single base mutations in a given DNA fragment. We adapted this method for the routine determination of allele variants of human alcohol and acetaldehyde dehydrogenase without radioisotopic labeling. After PCR amplification of the selected exon, the DNA fragments were heat-denatured and loaded on a polyacrylamide gel containing glycerol. For electrophoresis a discontinuous buffer system was used with sulfate as leading ion and borate as trailing ion. The DNA bands were revealed by silver staining. Acrylamide concentrations, ionic strength and electrophoresis temperature were systematically investigated for each DNA fragment. The polymorphisms detected by SSCP were identical to those found by hybridization with 32P-labeled allele-specific oligonucleotides. This method avoids the use of radioactivity, is less expensive and simpler than the allele-specific oligonucleotide (ASO) methodology and thus particularly suited for routine analysis.

Alcohol Dehydrogenase↗
PubMed1993

Effect of prestorage leukocyte reduction on proteins of platelets obtained by apheresis.

The effect of prestorage leukocyte reduction was evaluated on platelet concentrates (PCs) obtained by apheresis using the 'surge' technique. Two hours after collection, the PCs were divided into 2 equal units. One unit was filtered through a Sepacell PL-10a, producing a filtered PC (FPC). The second unit constituted a non-filtered PC (NFPC). FPCs and NFPCs were stored at room temperature in 1,400-ml CLX bags on a horizontal agitator up to 7 days. We analyzed platelet samples obtained during storage from NFPCs and FPCs at days 1, 3 and 7. The expression of membrane glycoproteins (GP)Ib and GPIIb/IIIa (assessed by flow cytometry), platelet response to thrombin and ristocetin (aggregometry) and global platelet protein pattern (studied by high-resolution two-dimensional gel electrophoresis) remained stable over the 7 days of storage in NFPCs as well as in FPCs. However, in both preparations, the expression of GMP-140 (flow cytometry) progressively increased during storage. Our in vitro study indicates that early leukocyte reduction by filtration of apheresis PCs does not induce modifications in platelet GPs and protein patterns.

Blood Platelets↗
PubMed1993

Wave packets analysis of two-dimensional protein maps: a new approach to study the diversity of immunoglobulins.

This report describes a mathematical approach for classifying two-dimensional (2D)-protein maps without spot detection or pattern matching. Analysis of electrophoretograms was performed using wave packet decompositions of the signals. The scanned images were automatically decomposed into a set of sub-images organized in a tree structure. Each sub-image contained relevant information such as its energy, or entropy. Moreover the node position itself of the sub-image reflected a frequency localization. A distance was then defined using the tree repartition of these quantities. Finally a statistical clustering on the tree structures was performed, terminating with a classification of the images according to their repartition frequencies. The algorithm has been applied to classify immunoglobulin (Ig) light chain patterns and proved useful to automatically detect monoclonal, oligoclonal or polyclonal Igs.

Algorithms↗
PubMed1993

Plasma/serum protein patterns in human fetuses and infants: a study by high-resolution two-dimensional polyacrylamide gel electrophoresis.

Plasma/serum proteins of fetal blood samples (N = 88) obtained under ultrasound guidance between the 18th and the 39th week of pregnancy, of blood samples collected from premature infants (N = 19), newborns at term (N = 20) and children of less than 5 years of age (N = 55) were analysed by high-resolution two-dimensional polyacrylamide gel electrophoresis. By comparison with adult 'reference' protein maps, tens of different proteins (and some of their genetic variants) were identified on the electrophoretograms. After the 18th week of gestation, albumin, transferrin, Factor B, glu- and lys-plasminogen, antithrombin III, Gc-globulin, alpha 1-antitrypsin, alpha 2-HS-glycoprotein, several apolipoproteins (apo A-I, A-II, A-IV, C-II, C-III, D, E, J), retinol-binding protein, transthyretin and alpha-fetoprotein could be observed. During intrauterine life, the size of the spots corresponding to alpha-fetoprotein progressively decreased, whereas the protein pattern globally showed an increase in the number and in the size of the spots. These modifications were particularly apparent in the regions of the electrophoretograms restricted to the heavy and light chains of IgG and to alpha 1-antichymotrypsin. In addition, we observed an unidentified fetal polypeptide characterized by an apparent molecular weight (M(r)) of 46 kDa (P46) and a pI of 5.0. P46 was present in all fetuses and all infants of less than 2 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Polypeptide marker and disease patterns found while mapping proteins in ascitis.

To assess the protein composition of ascitis, 28 samples of ascitic fluid were obtained from patients admitted to Geneva University Hospital. The samples were analysed randomly and blindly by high-resolution two-dimensional polyacrylamide gel electrophoresis. The final visual evaluation was compared with the discharged summary and diagnosis. The protein pattern of ascitis was, as expected, very similar to normal or diseased plasma, with the exception of two spots which were present in ascitic fluids but not in the 200 plasma samples analyzed in parallel. After microsequencing, they proved to be beta-fibrinogen fragments. Several diseases showed distinct patterns, especially acute pancreatitis. A group of intense spots with an apparent molecular mass between those of alpha 1-antitrypsin and beta-haptoglobin were found in all ascitic fluid from pancreatitis cases (six patients). These spots had isoelectric points similar to those of alpha 1-antitrypsin and beta-haptoglobin and microsequencing revealed that they were three different fragments of alpha 1-antitrypsin.

Acute Disease↗