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H G Schwick

Publications and source records attributed to H G Schwick.

At least 19 recordsLinked to original sources
PubMed1991

The effect of the carbohydrate moiety upon the size and conformation of human plasma galactoglycoprotein as judged by electron microscopy and circular dichroism. Structural studies of a glycoprotein after stepwise enzymic carbohydrate removal.

Galactoglycoprotein is a unique human plasma protein [76% carbohydrate (23% N-acetylneuraminic acid, 20% galactose, 3% mannose, 1% fucose and 29% N-acetylgalactosamine plus N-acetylglucosamine) and 24% polypeptide, a single polypeptide chain of about 200 amino acid residues that is high in serine and threonine content] [Schmid, Mao, Kimura, Hayashi & Binette (1980) J. Biol. Chem. 255, 3221-3226]. Highly purified exoglycosidases with well-defined specificities were used to prepare five derivatives of galactoglycoprotein in which sequential residues of N-acetylneuraminic acid, galactose, N-acetylglucosamine, a second galactose and N-acetylgalactosamine were removed with 83% of the total carbohydrate cleaved. C.d. shows that native galactoglycoprotein and all derivatives in aqueous buffer are predominantly random coil, suggesting that removal of a large number of electrostatic net charges, as well as the major portion of the carbohydrate moiety, does not alter the secondary structure of the polypeptide chain. Examination of the size and conformation of tungsten-shadowed galactoglycoprotein and asialo and agalacto derivatives by electron microscopy shows the size and conformation of all three preparations to be similar, with only minor differences in particle length and width.

Antigens, CD↗
PubMed1991

[Clinical importance of human plasma proteins and their future development].

For more than 50 years now, proteins based on human blood plasma are used as drugs. More than 20 different protein preparations: Albumin, immunoglobulins, coagulation factors and inhibitors are currently available for substitution therapy. In the near future, antihemophilic globulins and perhaps Factor IX, too, will be produced by genetic engineering, independent from human blood plasma. Albumin and immunoglobulins as well as a number of plasma proteins for which only a small field of indication exists will continue to be produced from blood plasma. On a long-term basis, part of the immunoglobulins with special antibody titers will be replaced by human monoclonal antibodies.

Blood Coagulation Factors↗
PubMed1991

[Poliomyelitis in Landsteiner's time and today].

At a meeting of the Royal and Imperial Association of Physicians in Vienna on December 18, 1908 Dr. Karl Landsteiner reported on the successful experimental transmission of poliomyelitis from man to ape in a study which he undertook together with Erwin Popper. In a scientific article that was published shortly after the meeting, Landsteiner wrote that "the poliomyelitis virus belongs to the group of filterable micro-organisms". Soon, Landsteiner's results were confirmed by other colleagues. During a congress in Washington 1912 Landsteiner declared that the development of a vaccine against poliomyelitis might prove difficult but was certainly possible in his opinion. It took another 45 years before the first polio vaccine was available (1955 Salk) and another 5 years until the oral vaccine (1960 Sabin) was implemented. The incidence of poliomyelitis decreased dramatically in industrial countries as a result of vaccination. Today, poliomyelitis is still an enormous threat in developing countries. Together with many national and international institutions the WHO fights this situation very hard by means of vaccination campaigns. The incidence of side effects and insufficient reactions is small with both vaccines. New techniques in the field of molecular biology and a good knowledge of the poliovirus make it likely that further improvements on the vaccines which are currently available will take place.

Austria↗
PubMed1988

Complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein and its homology to histocompatibility antigens.

In the present study the complete amino acid sequence of human plasma Zn-alpha 2-glycoprotein was determined. This protein whose biological function is unknown consists of a single polypeptide chain of 276 amino acid residues including 8 tryptophan residues and has a pyroglutamyl residue at the amino terminus. The location of the two disulfide bonds in the polypeptide chain was also established. The three glycans, whose structure was elucidated with the aid of 500 MHz 1H NMR spectroscopy, were sialylated N-biantennas. The molecular weight calculated from the polypeptide and carbohydrate structure is 38,478, which is close to the reported value of approximately equal to 41,000 based on physicochemical measurements. The predicted secondary structure appeared to be comprised of 23% alpha-helix, 27% beta-sheet, and 22% beta-turns. The three N-glycans were found to be located in beta-turn regions. An unexpected finding was made by computer analysis of the sequence data; this revealed that Zn-alpha 2-glycoprotein is closely related to antigens of the major histocompatibility complex in amino acid sequence and in domain structure. There was an unusually high degree of sequence homology with the alpha chains of class I histocompatibility antigens. Moreover, this plasma protein was shown to be a member of the immunoglobulin gene superfamily. Zn-alpha 2-glycoprotein appears to be a truncated secretory major histocompatibility complex-related molecule, and it may have a role in the expression of the immune response.

Amino Acid Sequence↗
PubMed1986

Properties of acute phase proteins of human plasma.

Almost 50 years ago the term acute phase serum was used for the first time by Avery and his colleagues to characterize serum from patients in an acute state with inflammatory diseases and which contained C-reactive protein. In the meantime a variety of proteins was detected in human blood plasma which are subject to the acute phase response. About a fifth of the until today more than hundred isolated and well characterized plasma proteins are to be classified as acute phase proteins. In human plasma they exist in many various quantities. There is no functional relationship among acute phase proteins. They partly belong to the coagulation system or to the complement system or they are transport proteins and inhibitors. There's also no relationship regarding their physico-chemical properties. The majority of the acute phase proteins are glycoproteins of different molecular weight. However, CRP and SAA, which serum concentration can rise to one thousandfold above normal during an acute inflammatory process, are pure polypeptides. The interpretation of the present knowledge about the functional activities of the acute phase proteins has led to the opinion that they probably all play a role during inflammatory processes. It is believed that the acute phase response represents a physiological mechanism which provides the site of inflammation via the tissue fluid with increased concentrations of these proteins. The majority of the acute phase proteins is synthesized in hepatocytes. The stimulation of the synthesis is probably mediated through cytokines (IL1) which are released from macrophages at the site of tissue damage.

Acute-Phase Proteins↗
PubMed1984

The structure of the carbohydrate units of human plasma galactoglycoprotein determined by 500-megahertz 1H NMR spectroscopy.

Human plasma galactoglycoprotein (Mr = 81,000) which was recently identified and characterized (Schmid, K., Mao, S. K. Y., Kimura, A., Hayashi, S., and Binette , J. P. (1980) J. Biol. Chem. 255, 3221-3226) was found to possess an unusually high carbohydrate content (76%) comprised of NeuAc, Gal, Man, Fuc, GalNAc, and GlcNAc. The aim of the present investigation was to elucidate the primary structure of the oligosaccharide units of this protein. For the study of the O-glycosidic oligosaccharide chains, the protein was subjected to beta-elimination and the resulting oligosaccharide preparations were analyzed by 500-MHz 1H NMR spectroscopy. The structure of the predominant glycan, a hexasaccharide: (formula; see text) and that of a tetrasaccharide: NeuAc alpha(2----3)Gal beta(1----3)[NeuAc alpha (2----6)]GalNAc-ol, were determined. The protein possesses approximately 40 hexasaccharides and 3 tetrasaccharides/mol. For the isolation of its N-glycosidic oligosaccharide chains, the protein was exhaustively digested with proteases followed by chromatography of the desialyzed resulting glycopeptide fraction on concanavalin A-Sepharose. 500-MHz 1H NMR spectroscopy of the obtained preparations revealed the presence of 3 diantennary N-glycosidic chains that are extended with a Fuc residue at the Asn-linked GlcNAc.

Carbohydrate Sequence↗
PubMed1981

Purified human plasma proteins of unknown function.

The development of new analytic and preparative techniques in the field of protein chemistry has essentially extended our knowledge about the variety of human plasma proteins in the last 15 years. In many cases plasma proteins have been particularly determined by immunologic techniques, partially highly purified and physicochemically well characterized, before knowing the biological function. To these proteins belong among others the alpha 1-antitrypsin, Cl-inactivator, alpha 2-macroglobulin, Gc-globulin and the cold-insoluble globulin. Today we know more than 100 proteins being isolated from human plasma and among these are nearly 20, of which the biological function is not yet known. To this group are belonging proteins, which are known since many years, like the alpha 1-acid glycoprotein and the C-reactive proteins as well as proteins, which have only been described in the last years and which partially have an interesting chemical structure, e.g. the histidinerich 3,8S-alpha 2-glycoprotein and the leucine-rich 3,1S-alpha 2-glycoprotein, of which every fifth amino acid is formed by leucine. It is to be hoped that the special chemical structure of some of these human plasma proteins as well as the quantitative immunologic determination in different patient sera will give hints to their biological function.

Alpha-Globulins↗
PubMed1978

Additional precipitation reactions of lectins with human serum glycoproteins.

Highly purified human serum glycoproteins were treated with neuraminidase and examined for their cross reaction with several lectins with anti-galactosyl specificity: beta-D-galactosyl structures are thought to be the main terminal sugar residues that become attached de novo after removal of neuraminic acid. The following lectins were tested: Tridacnin from the bivalve clams Tridacna maxima and Tridacna gigas, the agglutinin from the sponge Axinella polypoides, the lectin from the roach Rutilus rutilus and the plant lectins from Ricinus communis, Ononis spinosa, Glycine soja and Abrus precatorius. In agar gel diffusion, these purified and precipitating lectins gave more or less strong or negative results against the different neuraminidase-treated serum glycoproteins, thus indicating subtle differences with respect to their anti-galactosyl combining specificity. On the other hand, serum glycoproteins which reacted with the same lectin, did not always show complete identity lines. Finally, as revealed by these lectins, the carbohydrate moiety of serum glycoproteins may reflect a complex and broad spectrum of heterogeneity. This could lead to a more detailed understanding of the topographical and steric arrangement of the chemical structure and of the biological role of carbohydrate groups in these glycosubstances.

Animals↗
PubMed1977

Neuraminidase and tumor immunotherapy.

Preliminary results of first clinical studies with the enzyme neuraminidase call attention to a new kind of cancer treatment. This promising approach to tumor immunotherapy was entered into the clinical phase as a consequence of successful experimental studies in tumor-bearing mice, rats and dogs. In this review, the presently known and essential results of experimental and clinical studies on tumor immunotherapy by means of neuraminidase are presented as well as some necessary and critical considerations in this context. Moreover, out of a broad variety of results of biochemical and biological in vitro studies, it was attempted to select the more essential knowledge which could contribute to a better understanding of the still rather unclear in vivo mode of action of the enzyme neuraminidase. In a first brief paragraph (1.0), the biochemically characteristic data of the enzyme neuraminidase is presented. In the second section (2.0), the basic knowledge about the effects of neuraminidase on cell behavior is rather amply contained. Here, on the one hand, the biophysical and biochemical alterations are mentioned, the so-called ""unmasking'' effects are reconsidered and, on the other hand, the effects on the immunologically responding cell are discussed. In a third section (3.0), the diverse findings from animal experiments using neuraminidase-treated tumor cells are confronted, whereby tumor transplantation experiments and tumor therapy experiments are dealt with separately. The last section (4.0) reports about the first clinical studies with neuraminidase-treated autologous as well as homologous tumor cells, which partly brought about rather surprising and astonishing success. On the basis of recent findings by the study group of the authors, the more prior and sometimes discrepant results of various groups are critically considered. The problems of alteration of antigenicity and of other properties of cells through splitting off membrane-bound neuraminic acid, the facts of adjuvanticity of neuraminidase itself, the relation of successful therapy to dose dependency as well as the relation of undesirable methods for tumor mass reduction to the immunological responsiveness of the tumor bearer were especially looked into.

Animals↗
PubMed1977

A new marker for neuraminidase-treated human serum glycoproteins from the haemolymph of Tridacna maxima (Röding).

Highly purified human serum glycoproteins were treated with neuraminidase. The exposed subterminal carbohydrate structures reacted strongly with an anti-galactan precipitin from the haemolymph of Tridacna maxima which detects terminal, non-reducing beta-D-galactoside residues. This invertebrate precipitin, Tridacnin, may be used as a marker for nearly two thirds of all asialo serum glycoproteins; A number of different cross-reactions with various other polysaccharides and galactans subdivides those neuraminidase-treated glycoproteins into several subgroups, indicating that the uncovered carbohydrate structures are not always completely identical. In this way, together with the cross-reacting precipitins from plant and invertebrate origin. Tridacnin may be a useful tool for elucidating and establishing the structure of the carbohydrate part of serum glycoproteins.

Animals↗