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J Schaller

Publications and source records attributed to J Schaller.

At least 109 records · Page 6Linked to original sources
PubMed1987

Isolation, characterization and amino-acid sequence of gamma-seminoprotein, a glycoprotein from human seminal plasma.

gamma-Seminoprotein (gamma-SM), a glycoprotein from human seminal plasma, was isolated in highly purified form by ion-exchange chromatography on a Mono Q column. The main form, fraction M, was homogeneous by PAGE at pH 8.3 and by SDS-PAGE. The complete amino acid sequence of gamma-SM was determined with the aid of fragments generated by cleavages with cyanogen bromide, clostripain, chymotrypsin and Staphylococcus aureus V8 protease. The fragments were aligned with overlapping sequences. The single polypeptide chain of gamma-SM contains 237 amino acids with a calculated Mr of 26079. A single N-linked carbohydrate side chain is attached to Asn45. The complex structure of this oligosaccharide has been determined recently [van Halbeek H. et al. (1985) Biochem. Biophys. Res. Commun. 131, 507-514]. Sequence comparison with serine proteases shows a high degree of homology, especially with the kallikrein family. The residues in the vicinity of the active site of serine proteases are also highly conserved in gamma-SM, indicating the participation of His41, Asp96 and Ser189 in its active site. gamma-SM hydrolyzed M-casein with a pH optimum at 8.0, but failed to hydrolyze any of the synthetic substrates tested. This proteolytic activity could be inhibited with diisopropylfluorophosphate, phenylmethylsulfonyl fluoride, Zn2+ or Hg2+ ions.

Amino Acid Sequence↗
PubMed1987

T-helper cell activation in bullous pemphigoid.

In 10 untreated patients suffering from acute bullous pemphigoid the number of peripheral blood T cells (CD 3), T suppressor (CD 8) and T helper cells (CD 4) as well as activation antigens (DR and Tac) bearing lymphocytes was evaluated by monoclonal antibodies. While the pan-T cell population (CD 3) and T suppressor subpopulation (CD 8) were normal, the T helper subpopulation (CD 4) and the number of DR and Tac positive lymphocytes were significantly increased in the acute stage of bullous pemphigoid when compared to the age- and sex-matched controls. Phenotypically those DR positive cells belonged to the pan-T cell population (CD 3) at 66% and to the T helper subpopulation (CD 4) at 53% respectively. Under treatment with immunosuppressants the cell counts returned to normal suggesting a T helper cell activation to be involved in the acute stage of bullous pemphigoid.

Antigens, Surface↗
PubMed1986

Isolation and characterization of the structural gene for secreted acid phosphatase from Schizosaccharomyces pombe.

The Schizosaccharomyces pombe acid phosphatase structural gene (PHO 1) was isolated by complementation of an S. pombe acid phosphatase mutant with a wild type S. pombe DNA recombinant plasmid library. Northern analysis indicates that acid phosphatase is encoded by a 1.4-kilobase mRNA of which approximately 100 bases are 3'-poly(A). The gene contains no introns and the 3' and 5' untranslated regions are short. According to DNA and amino acid sequence data, the S. pombe acid phosphatase has a molecular weight of 50,600. An 18-amino acid sequence at the N terminus was found that is similar to previously identified signal peptides in other eukaryotic secretory proteins. This signal peptide is apparently removed during secretion, since it is absent in the mature secreted acid phosphatase. The gene can be induced 2--3-fold by starvation for phosphate. The signals required for this induction are contained on the isolated DNA clone. Although the gene can be expressed in Saccharomyces cerevisiae, secretion is abnormal.

Acid Phosphatase↗
PubMed1985

Complete amino acid sequence of bovine plasminogen. Comparison with human plasminogen.

The amino acid sequence of the single polypeptide chain of bovine plasminogen (786 residues, Mr 88092) was determined. Cleavage with CNBr yielded 13 fragments of which six originated from cleavage sites different from human plasminogen. Digestion with elastase gave three major fragments: kringles (1 + 2 + 3) and kringle 4, both with intact lysine binding sites, and mini-plasminogen. Subfragmentation was achieved mainly with 2-(2-nitrophenylsulfenyl)-3-methyl-3'-bromoindolenine (BNPS-skatole), Staphylococcus aureus V8 protease and trypsin. The sequences of fragments which were determined by automated Edman degradation, were aligned with overlapping sequences, or, in a few instances, by homology with the known sequence of human plasminogen. Sequence comparison with the human protein showed varying degrees of homology in the different functional and structural domains. The overall identity (78%) is practically the same as that found in those regions corresponding to the heavy (79%) and the light chain (80%) of plasmin. The average degree of identity among the kringles is 83%. Outside the kringle structures the extent of identity decreases, to 65% in the N-terminal region and to about 50% in the connecting strands between the kringles except for the strand between kringles 2 and 3, where only one out of 12 residues is exchanged. The results reported show that bovine plasminogen apparently contains the same structural and functional domains as human plasminogen. Bovine plasminogen also contains two carbohydrate moieties. The only partially substituted N-glycosidic site, Asn289, corresponds to partially glycosylated Asn288 in human plasminogen, whereas the O-glycosidic site of the human sequence, Thr345, is shifted to Ser339 in bovine plasminogen.

Amino Acid Sequence↗
PubMed1985

Determination of the complete amino-acid sequence of porcine miniplasminogen.

The complete amino acid sequence of porcine miniplasminogen (Mr 37 600), comprising 341 residues, was determined by automated Edman degradation in a liquid-phase or solid-phase sequenator. Selected fragments were produced by cleavage with 2-(2-nitrophenylsulfenyl)-3-methyl-3'-bromoindolenine (BNPS-skatole), cyanogen bromide, hydroxylamine, Staphylococcus aureus protease or trypsin or with combinations thereof and by activation with urokinase. The sequence obtained was compared with the known sequences of human and bovine miniplasminogen, indicating that the porcine molecule apparently contains the same structural and functional domains as the protein of the other two species. Porcine miniplasminogen has a sequence homology of 83% with human and of 79% with bovine miniplasminogen; 74% of the amino acids are identical in all three species. The results show a higher degree of evolutionary conservatism in the structurally and/or functionally vital regions of the molecule (active site residues, kringle 5).

Amino Acid Sequence↗
PubMed1984

Group-directed modification of bacteriorhodopsin by arylisothiocyanates. Labeling, identification of the binding site and topology.

Group-directed hydrophobic modification of membrane-integrated protein segments by arylisothiocyanates is applied to bacteriorhodopsin. Labeling of purple membrane with phenylisothiocyanate and 4-N,N'-dimethylamino-azobenzene-4'-isothiocyanate results in covalent modification of a unique lysine epsilon-amino group of bacteriorhodopsin. Lysine residue 41, located in the amino-terminal chymotryptic fragment, has been identified as the arylisothiocyanate binding site by established sequencing techniques. The phenylisothiocyanate binding site is not accessible for the aqueously soluble analog p-sulfophenylisothiocyanate. Furthermore, the acid-induced bathochromic shift of the bound chromophore reagent is not observed following acidification of 4-N,N'-dimethylamino-azobenzene-4'-isothiocyanate-labeled purple membrane. The modification thus occurs in the hydrophobic membrane domain, providing further evidence for intramembraneous disposition of the modified protein segment. Light-induced proton translocation is preserved in reconstituted vesicles containing either phenylisothiocyanate-modified or 4-N,N'-dimethylamino-azobenzene-4'-isothiocyanate-modified bacteriorhodopsin.

Amino Acid Sequence↗
PubMed1984

The advantages of hemodilution anesthesia for major liver resection in children.

Since 1977, eight children have had major liver resections with the aid of normovolemic hemodilution anesthesia. Five children were 7 months of age or less; the other three were 3 1/2, 8, and 12 years old. This includes three operations for hepatoblastoma, three for hepatoma, and two for mesenchymal hamartoma. There were three right lobectomies, two trisegmentectomies, two extended left lobectomies, and one standard left lobectomy. With the use of this method, operative blood loss has been greatly reduced and operating technique significantly improved. After abdominal exploration and initial liver mobilization, whole blood is removed from the patient and simultaneously replaced with three times the volume of Ringer's lactate solution to maintain adequate intravascular volume. After the major blood loss has ceased, the patient is reinfused with his own blood and a simultaneous diuresis is induced with LASIX to remove the previously administered crystalloid solution. Metabolic demand is reduced by allowing the patient's temperature to drift down to 32 degrees C. Blood loss is further reduced by a Halothane-induced hypotension to a mean arterial pressure of 40 to 50 torr. The diluted blood lost during surgery has a low red blood cell volume per cc; therefore, each cc of blood lost depletes the total red cell volume by a lesser amount. This results in a nearly bloodless operative field which facilitates the ease, speed, and safety of the dissection. Use of this technique can avoid the need for massive intra-operative transfusions and the threat of cardiac arrest due to extensive blood loss during major liver resection in children.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, General↗
PubMed1983

Site-directed fluorogenic modification of bacteriorhodopsin by 7-chloro-4-nitrobenz-2-oxa-1,3-diazole.

Site-directed covalent modification of bacteriorhodopsin is achieved by reacting the hydrophobic probe 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl) at neutral pH with purple membranes. The bacteriorhodopsin fluorescence thus produced is specific for a nucleophilic group. The spectral properties of NBD-modified bacteriorhodopsin indicate covalent interaction of the probe with the nucleophilic epsilon-amino group of a lysine residue. Modification of tyrosine can be excluded. As demonstrated by polypeptide fragmentation and subsequent sequence analysis, NBD binding is confined to lysine 41 within the primary structure of bacteriorhodopsin. Collisional fluorescence quenching with iodide demonstrates that, in NBD-treated purple membranes, the covalently bound label is not accessible in the aqueous phase. A hydrophobic location for the introduced fluorophor is thereby implied.

4-Chloro-7-nitrobenzofurazan↗
PubMed1983

Hemodilution anesthesia: a valuable aid to major cancer surgery in children.

Since 1974, 25 children had 27 major cancer operations with the aid of hemodilution anesthesia. This includes operations for Wilms' tumors, liver tumors, adrenal tumors, pancreatic tumors, ovarian tumors, and resection of metastatic thoracoabdominal tumors. With the use of this method, operative blood loss has been greatly reduced and operative technique improved. At the beginning of surgery, whole blood is removed from the patient and replaced with three times the volume of a balanced electrolyte solution to maintain intravascular volume. After the time of significant blood loss has ceased, the patient's own blood is returned and diuresis stimulated with furosimide to remove the infused electrolyte solution. Hypothermia, allowing the temperature to drift down to just below 32 degrees C, helps protect vital organs against hypoxia and arterial hypotension to a mean of 50 torr systolic pressure is well tolerated and further reduces blood loss. Adequate tissue oxygenation can be maintained safely during hemodilution to a hematocrit value of 14 percent. Use of bank blood transfusion was necessary in only 6 of 25 patients. It was given when the calculated postoperative hematocrit value would be less than 30 percent. The diluted blood lost during surgery has a low red blood cell volume per milliliter and each milliliter lost depletes the total red blood cell volume by a lesser amount. Also, the ease and speed of surgery may be facilitated by the nearly bloodless operative field. Provided respiratory support is maintained, these children showed only minor clinical effects from this large fluid infusion. The majority of patients who are Jehovah's Witnesses accept this technique with the modification that we keep the blood moving and in direct contact with the patient's vascular system. Carefully planned and meticulously applied short-term hemodilution anesthesia provides a safe method for minimizing operative blood loss and reduces the difficulty of major cancer surgery in children.

Anesthesia↗
PubMed1982

Improved survival in children with osteosarcoma following resection of pulmonary metastases.

Despite the effectiveness of improved chemotherapy and radiotherapy, surgical resection of all gross metatastic disease from the lung appears to improve the survival of children with osteosarcoma. At Children's Orthopedic Hospital and Medical Center (COHMC), from 1952 through 1980, 55 patients were treated for osteosarcoma. Twenty-eight of these patients (4 with active disease) were surviving in January 1981. Six patients had pulmonary metastases at diagnosis and 28 patients developed pulmonary metastases after diagnosis. From 1964 through 1980, 17 patients had 34 thoracotomies for resection of metastases. Seven of these 17 patients (41%) are surviving and remain free of disease. The disease was often bilateral, and in most patients more than one thoracotomy was required to erradicate recurrent disease. No patient who developed pulmonary metastases from osteosarcoma survived without surgical resection of all gross disease. An aggressive surgical approach to the treatment of osteosarcoma metastatic to the lung in children appears worthwhile.

Adolescent↗
PubMed1982

Human low-molecular-weight urinary urokinase. Partial characterization and preliminary sequence data of the two polypeptide chains.

Low-molecular-weight urokinase (molecular weight 33100) was separated by analytical and preparative isoelectric focusing into five major subforms with isoelectric points between 8.7 and 9.6. These subforms are very similar in molecular weight, specific activity, amino acid composition and content of amino sugar and their N-terminal sequence constellation is identical. Low-molecular-weight urokinase consists of two polypeptide chains connected by a single disulfide bridge. The N-terminal region of the heavy chain (calculated Mr 30700) exhibits homology within the first 46 residues analyzed, with the known primary structure of other serine proteases. The mini chain (Mr 2426), whose complete sequence was determined, consists of 21 residues which show homology with the primary structure of the C-terminal region of the plasmin heavy chain. Based on sequence data and homology criteria with serine proteases a single-chain urokinase precursor is postulated having a peptide bond constellation between heavy and light chain region compatible with the requirements for serine protease activation.

Amino Acid Sequence↗
PubMed1982

[Decrease in the number of SE-rosettes by means of sera containing immune complexes].

The number of peripheral blood lymphocytes (PBL) rosetting with sheep erythrocytes (SE-rosettes) was significantly decreased by preincubation with both sera containing immune complexes (IC) and prepared antigen-antibody complexes. However, this effect of decrease in rosetting ability of PBL could be completely reversed by a second incubation of the cells for 30 minutes at 37 degrees C in IC-free medium. The immune complexes and antigen-antibody complexes respectively could bind reversibly to T cells via Fc-receptors and subsequently interfere with the T cell receptors for SE by steric hindrance.

Animals↗
PubMed1981

Comparison of the primary structure of the N-terminal CNBr fragments of human, bovine and porcine plasminogen.

The primary structures of the N-terminal CNBr fragment of human, bovine and porcine plasminogen were determined by automated Edman degradation in a combination of liquid and solid-phase techniques and also by applying the carboxypeptidase method. The comparison of the fragments showed three highly homologous and two variable regions. The heptapeptide sequence responsible for intramolecular interaction is preserved in a conservative region, whereas the sequence of the acidic loop varies considerably between the species. In the bovine and porcine fragments 18 of the 57 residues are exchanged when compared with the fragment of human plasminogen, whereas only 11 exchanges occur between the two fragments of animal origin.

Amino Acid Sequence↗