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H Haas

Publications and source records attributed to H Haas.

At least 19 recordsLinked to original sources
PubMed1992

Purification, characterization and partial amino acid sequences of a xylanase produced by Penicillium chrysogenum.

An extracellular xylanase (1,4-beta-D-xylan xylanohydrolase, EC 3.2.1.8, endo 1,4-beta-xylanase) was found to be the major protein in the culture filtrate of Penicillium chrysogenum when grown on 1% xylan. In contrast to other microorganism no xylanase multiplicity was found in P. chrysogenum under the conditions used. This enzyme was purified to homogeneity by high performance anion-exchange and size-exclusion chromatography. It had an M(r) of 35,000 as estimated by SDS-PAGE and was shown to be active as a monomer. No glycosylation of the protein could be detected neither by a sensitive glycostain nor by enzymatic deglycosylation studies. The enzyme hydrolyzed oat spelt and birchwood xylan randomly, yielding xylose and xylobiose as major end products. It had no cellulase, CMCase, beta-xylosidase or arabinogalactanase activity but acted on p-nitrophenylcellobioside. The pH and temperature optima for its activity were pH 6.0 and 40 degrees C, respectively. Eight peptides obtained after endoproteinase LysC digestion of xylanase have been sequenced, six of them showed considerable amino acid similarity to glucanases and high M(r)/acidic xylanases from different bacteria, yeasts and fungi.

Amino Acid Sequence↗
PubMed1992

Calcium-dependent and calcium-independent signals in the conglutinin-binding assay (KgBa) for immune complexes. Influence of anti-collagen-antibodies.

A solid phase ELISA conglutinin-binding assay (KgBa) was evaluated for the detection of circulating immune complexes. ELISA wells were coated with purified bovine conglutinin and incubated with test sera. Bound IgG was detected with enzyme labelled anti-immunoglobulin. Heat aggregated IgG which had been "solubilized" (i.e., complement treated by incubation with serum) was employed as a reference. The binding of the complement-reacted IgG to solid phase conglutinin was found to be calcium-dependent and inhibitable with N-acetyl-D-glucosamine (GlcNAc). Prolonged incubation (4 days) of aggregated IgG with serum at 37 degrees C abolished the binding to conglutinin, a finding consistent with the complete degradation of deposited C3b to C3c and C3d. The solubilized IgG that bound to solid phase conglutinin was found by gel chromatography to be of high molecular weight (greater than 600 kDa). Binding of IgG to solid phase bovine conglutinin was also observed to a variable degree in normal and pathological sera. However, in this situation the IgG binding was largely calcium-independent, was not inhibited by GlcNAc and did not decrease after prolonged incubation of the serum at 37 degrees C. The reactive IgG eluted on gel chromatography at the position of monomeric IgG suggesting binding via the antigen binding sites. Binding of this IgG was inhibited by both collagen type II and purified conglutinin. These observations suggest that the assay detects cross-reacting autoantibodies against collagen epitopes, or, alternatively, antibodies against the dietary antigen, bovine conglutinin.

Acetylgalactosamine↗
PubMed1992

Isolation and analysis of the Penicillium chrysogenum phoA gene encoding a secreted phosphate-repressible acid phosphatase.

We have isolated the genomic sequence encoding a secreted phosphate-repressible acid phosphatase (PHOA) from Penicillium chrysogenum using synthetic oligodeoxyribonucleotide probes. Nucleotide sequence data revealed that this gene consists of two exons of 192 and 1047 bp separated by an intron of 52 bp in length. A sequence encoding a putative signal peptide, resembling known signal sequences of fungi, was identified at the 5'-end of the coding sequence. Northern blot analysis of total cellular RNA indicated that the phoA gene codes for a 1.6-kb transcript. The expression of this gene is regulated at the transcriptional level and is markedly affected by the inorganic phosphate concentration of the growth medium.

Acid Phosphatase↗
PubMed1992

Characterization of a human-human hybridoma antibody, C-OU1, directed against a colon tumor-associated antigen.

The human hybridoma cell line, B9165, was obtained after fusion of lymphocytes from lymph nodes draining the tumor region in a patient with adenocarcinoma of the colon with the human B-lymphoblastoid cell line WI-L2-729-HF2 (729-HF2). B9165 secretes the human monoclonal antibody, C-OU1 (IgM, kappa). Immunocytochemical and immunohistochemical analysis showed that the antibody bound to a differentiation antigen. Electron microscopy of colonic adenocarcinoma cells, intact tumor and colonic epithelium by the immunogold technique demonstrated that the C-OU1 antibody reacted with a molecule associated with areas of disruption of the intermediate filaments in the cytoplasm of the tumor cells. No reaction was seen with intermediate filaments in normal colonic epithelium. The molecular weight of the antigen was shown to be 43 Kda by SDS-PAGE and Western blotting of tumor extracts, and isoelectric focusing of sonicated extracts demonstrated reaction with molecular species of pI 5.4-6.2. These findings suggest that the C-OU1 antigen is a modified cytokeratin 18. The B9165 cell line has proved to be quite stable, and the antibody is of potential clinical value. Its usefulness for localizing tumors in patients is being investigated.

Antibodies, Monoclonal↗
PubMed1992

Augmentation of the antibacterial activity of magainin by positive-charge chain extension.

Novel analogs of the broad-spectrum antimicrobial peptide magainin-2 were obtained by extension of its chain through addition of segments of positively charged amino acids to either its N or its C terminus and by increasing its helicity. The activity of magainin-2 toward American Type Culture Collection strains of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus was most considerably enhanced by these modifications, whereas, in general, its low hemolytic capacity was not or was only slightly affected. The antibacterial potencies of magainin-2 and its derivatives were more evident following decreases of pH from 7.2 to 6 and 5.

Amino Acid Sequence↗
PubMed1992

[The severely injured patient in the emergency center--new diagnostic, therapeutic and organizational concepts].

Recent advances in clinical intensive care medicine and legal aspects of quality assurance require new concepts and methods in preclinical emergency medicine. Different new methods of emergency medicine are presented and evaluated as to their economy, practicability, and medical efficacy, points which have to be considered in order to make general recommendations.

Cost-Benefit Analysis↗
PubMed1991

Penicillium chrysogenum extracellular acid phosphatase: purification and biochemical characterization.

An extracellular acid phosphatase (EC 3.1.3.2) from crude culture filtrate of Penicillium chrysogenum was purified to homogeneity using high-performance ion-exchange chromatography and size-exclusion chromatography. SDS-PAGE of the purified enzyme exhibited a single stained band at an Mr of approx. 57,000. The mobility of the native enzyme indicated the Mr to be 50,000, implying that the active form is a monomer. The isoelectric point of the enzyme was estimated to be 6.2 by isoelectric focusing. Like acid phosphatases from several yeasts and fungi the Penicillium enzyme was a glycoprotein. Removal of carbohydrate resulted in a protein band with an Mr of 50,000 as estimated by SDS-PAGE, suggesting that 12% of the mass of the enzyme was carbohydrate. The enzyme was catalytically active at temperatures ranging from 20 degrees C to 65 degrees C with a maximum activity at 60 degrees C and the pH optimum was at 5.5. The Michaelis constant of the enzyme for p-nitrophenyl phosphate was 0.11 mM and it was inhibited competitively by inorganic phosphate (ki = 0.42 mM).

Acid Phosphatase↗
PubMed1991

[Biomechanical properties of heat and irradiation treated spongiosa].

Cylindrical specimens of trabecular pig bone were tested to uniaxial compressive strain levels of 30% to study the influence of various sterilization techniques and methods of HIV-inactivation on the mechanical properties characterized by compressive modulus, yield point, energy absorption and maximum stress. Heat inactivation at 60 degrees C (Lactated Ringer, 1 h) showed no effect; 80 degrees C (Lactated Ringer, 1 h) resulted in a diminution of the yield point and the maximum stress (p less than 0.005), while energy absorption and compressive modulus were not affected. No reduction in the stability was seen when ethanol was used instead of Lactated Ringer. At a temperature of 100 degrees C, all measured parameters were reduced to approximately 60% compared with the control group. A decrease to 13% to 25% was seen after autoclavation (120 degrees C, 2 bar, 20 min and 134 degrees C, 3 bar, 12 min). Irradiation (60Co) with 3 respectively 10kGy did not impair the stability, whereas a dose of 25 kGy led to a reduction to 61% to 69%. No additional effect was seen when irradiation was followed by storage at -80 degrees C for one week. These effects on bone stability should be considered when choosing a method of bone preparation to obtain HIV-inactivated bone grafts. Autoclavation should be used with caution when stability of the bone graft is essential. In this case, irradiation seems to be a safe method of sterilizing bone grafts ensuring both a high degree of safety and stability.

Animals↗
PubMed1991

Prevalence and subclass distribution of IgG-anti-IgE autoantibodies in atopy and parasitosis.

Using immunoblotting, we investigated sera of 60 patients with atopic dermatitis, 12 patients with helminth infections and 36 nonallergic controls, for anti-IgE autoantibodies. We found IgG anti-IgE autoantibodies in 62% of the atopics, 42% of the patients with parasitosis and 11% of the controls. IgG anti-IgE occurred most often (94%) in patients with atopic dermatitis plus additional atopic disorder, such as allergic asthma and rhinoconjunctivitis. In parallel, we found a significantly higher occurrence of IgG anti-IgE in the patients with high IgE levels compared to patients with low IgE levels (p less than 0.0005). The predominant subclasses of anti-IgE autoantibodies were IgG1 and IgG3 in atopy and parasitosis. In the controls, we found IgG4 and IgG3 anti-IgE, but no IgG1 autoantibodies. The frequency of IgG2 anti-IgE was very low; it occurred in 2 patients only. Prevalence and IgG subclass distribution of anti-IgE autoantibodies was found to be different for patients with atopic dermatitis, parasitic infection and for controls.

Antibodies, Anti-Idiotypic↗
PubMed1991

Hypoxemia vs sleep fragmentation as cause of excessive daytime sleepiness in obstructive sleep apnea.

To determine the effects of intermittent hypoxemia on daytime sleepiness in the clinical setting of obstructive sleep apnea syndrome, we enrolled seven patients in a prospective, randomized, crossover study. We had two experimental conditions with NCPAP treatment as follow: (1) to correct apneas, sleep fragmentation, and hypoxemia; and (2) to correct apneas and sleep fragmentation and at the same time, induce intermittent hypoxemia. The outcome variable, daytime sleepiness, was measured objectively with the multiple sleep latency test following completion of baseline and each treatment condition. Compared with sleep latencies in the untreated condition, both experimental treatment arms prolonged sleep latencies (p less than 0.05). We found no statistically significant differences between mean MSLT scores obtained after NCPAP treatment under hypoxemic and nonhypoxemic conditions. In summary, two nights of intermittent nocturnal hypoxemia during NCPAP treatment for OSAS did not diminish the objective improvement in daytime somnolence seen with NCPAP treatment in the absence of nocturnal hypoxemia. Results lend further support to the hypothesis relating excessive daytime sleepiness to sleep fragmentation.

Adult↗
PubMed1990

Immunoblotting techniques for the detection of low level homogeneous immunoglobulin components in serum.

Because of the increasing demand for simple and reliable techniques for the detection of low concentrations of paraproteins against a highly heterogeneous serum background, two techniques were investigated for their sensitivity: isoelectric focusing (IEF) and Wieme high resolution electrophoresis, each with subsequent blotting by diffusion. The techniques were compared using isolated mouse monoclonal antibodies (mAb) of known concentration and specificity. Wieme electrophoresis in combination with immunoblotting (IBL) or antigen-specific immunoblotting (ABL) has a detection limit of 100 ng/ml and 10 ng/ml, respectively. For IEF in combination with IBL or ABL these limits were 1000 and 30 ng/ml, respectively. For ABL, polyvinylidene difluoride (PVDF) and nylon-supported nitrocellulose (NSNC) membranes gave similar detection limits, although for IBL, PVDF is preferred to NSNC. While IEF is essential for investigating the spectrum of the antibody repertoire. Wieme electrophoresis is the most powerful technique for the detection of homogeneous immunoglobulin components (H-Ig). After separation of the proteins. IBL is fast, simple and sensitive enough for routine detection and characterization of H-Ig. However, when the antibody specificity is known, ABL should be chosen for its superior sensitivity.

Animals↗
PubMed1990

[Prevention of HIV infection in the methadone program. A study of a drop-in clinic in Zurich].

We were able to show for 21 patients who were all HIV-negative at the beginning of the methadone maintenance program of the Drop-in in Zurich that they remained HIV-negative over an average period of 34 months. At the beginning of the program 48% of the patients had a good social integration with few contacts to the drug scene for buying or selling drugs. During the program this figure increased to 90%. Before starting the program 43% of these HIV-negative patients were at high risk (needle sharing). During the maintenance program 57% of the patients became clean of heroin and 76% clean of cocaine. The remaining obviously abstained from needle sharing due to a continuous information concerning HIV-prevention. We conclude that a well structured methadone maintenance program with a close, consistent and enduring relationship between staff and patients can be of great importance in HIV-prevention among IV drug abusers.

Adult↗
PubMed1990

Differential regulation of HLA class I genes by interferon.

Allele-specific differences in the regulation of HLA class I genes by type I interferon (IFN) were observed after transfection of eight HLA-B, -A, or -C genes into mouse L cells. HLA-B7 and -Bw64 gene expression was significantly more inducible by type I IFN than the genes coding for HLA-B27, HLA-B51, HLA-B38, HLA-B39, HLA-Cw3, and HLA-A2 antigens. Modification of the 5' end of HLA-B7 and HLA-B27 genes revealed the presence of enhancer sequences responding to IFN treatment in the 5' untranslated region of HLA-B7, but not of HLA-B27 and suggested further, independently acting enhancer elements downstream of the transcription initiation site. Comparison of 5' enhancer region sequences in correlation with type I IFN inducibility of the different HLA class I alleles indicated that the exchange of only two nucleotides in the interferon response sequence (IRS) or enhancer A region of HLA-B7 or -Bw64 could account for nonregulated promoters in all other HLA-A, -B, or -C alleles analyzed. Thus, type I IFN stimulation of HLA class I genes in mouse L cells appears to predominantly operate in most alleles by a mechanism targeted to enhancer sequences downstream of the gene's transcription initiation site.

Alleles↗
PubMed1990

Do infections induce monoclonal immunoglobulin components?

The incidental finding of monoclonal immunoglobulin components (MC) in some infections prompted us to study this phenomenon more systematically. Using isoelectric focusing with immunoblotting (detection limit for MC 0.1 mg/ml), the following infections were studied for the presence of MC: visceral leishmaniasis, cytomegalovirus (CMV) infection, echinococcosis and infectious mononucleosis. MC were found in 16 of 20 leishmania patients and in eight of 18 CMV patients, but in only one of 20 echinococcosis patients and in none of 30 infectious mononucleosis patients. The MC were mostly transient, where tested. A minority of the MC found in the leishmaniasis patients was shown to bind to leishmania antigens. The specificity of the majority of the MC remains unknown. Further study is required to explain the high incidence of MC in CMV infection and visceral leishmaniasis.

Adolescent↗
PubMed1990

[Neonatal nosocomial infection at a pediatric resuscitation and intensive care unit].

During 1989, a nosocomial infection rate of 3.15% was observed among the 412 neonates hospitalised for more than 2 days in the paediatric intensive care unit and a special care baby unit in the medical centre of Nice. Certain factors only partially explain the above, and it is probable that the non-invasive methods of monitoring and care and the experienced nursing staff contribute to a great extent to this low frequency of infection.

Cross Infection↗
PubMed1990

[Immunologic parameters in lung tuberculosis].

In patients with pulmonary tuberculosis serum immunoglobulin levels are found to be increased, quantitative deviations from the norm are observed on analysis of the mononuclear cells, there is an increase in the number of circulating immune complexes, and, in the event of extensive pulmonary involvement, an attenuation of cell-mediated cutaneous reactions is seen. In accordance with the chronic course of the disease, a return to normalcy of these parameters in the healing phase occurs only gradually.

Antigen-Antibody Complex↗