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Biomedical subjects

K Zimmermann

Publications and source records attributed to K Zimmermann.

At least 73 records · Page 4Linked to original sources
PubMed1995

Intra-species characterization of clinical isolates and biotechnologically used strains of Lactobacillus rhamnosus by analysis of the total soluble cytoplasmatic proteins with silver staining.

Lactobacillus rhamnosus is often used in milk products because of its technological properties, however it is supposed to be related to human infections as well. Therefore, 23 L. rhamnosus strains, including the type strain, were investigated. Nine strains resulted from biotechnological sources, 14 isolates had a clinical background, 13 came from a swedish culture collection. Biochemical and physiological properties were proved by classical tests. Analysis of the total soluble cytoplasmatic protein patterns was performed with diamine silver staining, a technique not previously applied to lactobacilli. Classical tests were able to confirm all strains as L. rhamnosus. Analysis of protein patterns allowed to differentiate between three clusters. Cluster I contained the type strain and biotechnologically used strains and one clinical strain isolated in Berlin. The second consisted of both, technological and clinical strains. The third cluster contained clinical isolates alone. SDS-PAGE of proteins together with diamine silver staining seems to be helpful to detect intra-species differences. It was stated, that technologically used strains of L. rhamnosus could clearly be differentiated from each other and also from clinical isolates.

Bacterial Proteins↗
PubMed1995

Development of a simple and selective separation of 67Cu from irradiated zinc for use in antibody labelling: a comparison of methods.

A procedure for the production and separation of Cu isotopes from irradiated Zn was developed. Following a comparison of methods based on extraction, electrolysis and ion-exchange chromatography, a technique for the separation of Cu employing three ion-exchange matrices was developed which was simple, reproducible and hot cell-compatible. The specific activity of the final product was 37 MBq 67Cu/microgram Cu at EOB. The level of impurities was so low that no interference with antibody labelling was observed.

Antibodies↗
PubMed1995

A purine-rich sequence in the human BM-40 gene promoter region is a prerequisite for maximum transcription.

BM-40 (osteonectin, SPARC [secreted protein, acidic, rich in cysteine]) is a highly conserved, matrix-associated protein that is found in basement membranes, bones and remodeling tissues throughout vertebrate evolution. We are reporting the characterization of the 5' end of the human BM-40 gene. Sequence comparison of the 5' region revealed significant homologies with the bovine and murine genes, including a purine-rich stretch composed of two boxes, GGA-box 1 and 2, separated by a pyrimidine-rich spacer element. Transfection analyses of the human BM-40 promoter provide strong evidence that this region comprises several distinct regulatory domains, to which different functions can be assigned. GGA-box 1 is thereby absolutely required and sufficient by itself for maximal BM-40 transcriptional activity, whereas the spacer element has a down-regulatory effect. Comparative transfection analyses in human cell lines, positive or negative for BM-40 transcripts, indicate that the GGA-box sequences in the human promoter, in contrast to the bovine promoter, do not significantly contribute to cell-type specific expression in human cells.

Adenosine↗
PubMed1995

Interaction with human immunodeficiency virus type 1 modulates innate effector functions of human monocytes.

The effect of human immunodeficiency virus (HIV) type 1 on human mononuclear phagocyte effector functions in response to infection with bacteria of the Mycobacterium avium-intracellular complex (MAC) was investigated. The results showed that interaction of HIV-1 or its constituents with CD4 expressed in the monocyte membrane led to substantial impairment of monocyte capacity to restrict the intracellular growth of MAC. This was accompanied by substantially decreased production of tumor necrosis factor-alpha by HIV-1-exposed and MAC-infected monocytes. However, productive HIV-1 infection of monocytes was not required to induce the observed effects. These studies suggest that HIV-1 may interfere with innate mononuclear phagocyte function. This may be of physiologic importance in the late stages of AIDS, when an impaired T cell immunity can no longer provide proper immune-activating signals, and may help to explain the undue susceptibility to MAC infections in these patients.

HIV-1↗
PubMed1995

[Growth of Candida albicans in normal and altered fecal flora in the continuous flow culture model].

We used the model of fecal microflora under continuous flow culture (cfc) conditions to study the growth of Candida albicans in mixed cultures. The development of Candida is usually limited by the high germ counts of aerobic and anaerobic bacteria. Neither by the continuous inflow of C. albicans-cfc-monocultures nor by intermittent input of highly concentrated suspensions of C. albicans into the system a growth in fecal flora could be obtained. If the system was run under aerobic conditions a development of C. albicans with few hyphal growth could be observed. After some days however, the fecal flora again suppressed a further development of the yeasts. Only a marked destruction of the aerobic and anaerobic microflora by antibiotics resulted in a growth or overgrowth of Candida albicans.

Anti-Bacterial Agents↗
PubMed1994

Lipoprotein-associated paf (LA-paf) was found in washed human platelets and monocyte/macrophage-like U937 cells.

Beyond cholesterol, inflammatory ether phospholipids such as platelet-activating factor (paf) may play a role in atherogenesis. (1) We detected a paf-like compound ('LA-paf') associated with human serum lipoproteins, mainly in LDL but not with the lipoprotein-poor fraction. (2) LA-paf was also found in washed human platelets, from where it was partially released during platelet aggregation in response to paf (50 nM) or thrombin (1 U). In addition, resident monocyte/macrophage-like U937 cells carried huge amounts of LA-paf (41 ng per 10(7) cells) and metabolized added [3H]paf to a labelled compound co-eluting with the retention time of LA-paf in standard HPLC. (3) Functionally, LA-paf had a comparable potency to synthetic paf, because LA-paf aggregated washed aspirin-treated platelets in a concentration-dependent manner. The specific paf receptor antagonist WEB2086 inhibited the platelet aggregation induced by three distinct LA-paf preparations as compared with synthetic paf with similar inhibitory concentrations (IC50: 35.6 +/- 12.8, 24.0 +/- 4.0, 38.0 +/- 15.8 nM for LA-paf, and 43.6 +/- 6.5 nM for synthetic paf), indicating that LA-paf interacted with paf receptors. (4) However, LA-paf had a distinct retention time using high-pressure liquid chromatography (HPLC) as compared with synthetic paf. LA-paf eluted at 9-15 min and synthetic paf at 21-24 min. In addition, total and non-specific [3H]paf binding to intact washed human platelets was affected differently by the two unlabelled agonists: while LA-paf increased total and non-specific (but not specific) binding in a significant manner (P < 0.002 and P < 0.007) as LDL did (P < 0.006 and P < 0.03), synthetic paf decreased total binding (P < 0.03). Similarly, low-density lipoproteins (LDL) increased significantly the total [3H]paf binding. In contrast, paf did not affect specific [125I]LDL binding to human fibroblasts. Our results show the presence of LA-paf in lipoproteins, washed human platelets and monocyte/macrophage-like cells. As LDL and LA-paf purified from the same LDL particles increased significantly the total [3H]paf binding to intact human platelets, it might modulate platelet adherence to vascular endothelial cells.

Animals↗
PubMed1994

Constitutive expression of chimeric neo-Rev response element transcripts suppresses HIV-1 replication in human CD4+ T lymphocytes.

We have previously reported that chimeric neomycin phosphotransferase (neo)-Rev response element (RRE) transcripts suppress the function of the human immunodeficiency virus type 1 (HIV-1) Rev trans-activator protein in HeLa cells. In an extension of these experiments, human CD4+ CEM cells (G418-resistant cell populations and clonal isolates) stably expressing chimeric neo-RRE genes (2, 3, or 6 RRE copies) were generated using retroviral-mediated gene transfer. The transduced CEM clones were infected with the HIV-1 HTLVIIIB isolate and the following three phenotypes were observed: (i) the transduced CEM cells were readily infected with HIV-1 indistinguishable from the control CEM cells; (ii) the appearance of HIV-1 replication markers was significantly delayed; (iii) no signs of HIV-1 replication were detectable although proviral HIV-1 DNA sequences could be detected in these cells. Furthermore, HIV antigen expression was limited in neo-resistant CEM cell populations inoculated with the HIV-1 HTLVIIIB isolate. Only 10% of the CEM-pX17-3xRRE cells and 20% of the CEM-pX17-2xRRE cells displayed HIV-1 antigens 43 days after challenge and had retained CD4 surface expression on 47% and 64% of the cells, respectively. In sharp contrast, 80% of the CEM-pX17 or the CEM-pX17-6xRRE cells expressed HIV-1 antigens but no CD4 antigens were detectable in these cultures. These results clearly indicate that RRE decoys could be developed into an effective somatic gene therapy approach against HIV-1 induced acquired immunodeficiency syndrome (AIDS).

Base Sequence↗
PubMed1994

When awaiting 'Bio' Champollion: dynamic programming regularization of the protein secondary structure predictions.

Predictions of protein secondary structure using current methods are often unrealistic, i.e. the predicted alpha-helices or beta-strands are too short. To improve the realism, various heuristic 'filtering' or 'smoothing' methods are used. They are more or less intuitive and are based on ad hoc corrections. We present a regularization method to obtain a realistic secondary structure from predicted propensities. It is based on the known dynamic programming algorithm and is quite objective. It can be used with any prediction method which yields propensities. The regularized predictions conserve well the overall prediction accuracy and improve the 'protein-likeness' of the prediction.

Algorithms↗
PubMed1994

[Dimorphism of Candida albicans in the model of continuous flow culture].

We investigated the opportunistic pathogen Candida albicans in a continuous flow culture with regard to particular growth conditions. Germ counts of only 10(7) cfu/ml were obtained in a steady state of an anaerobic culture. In a parallel experiment with aerobic conditions excessive growth occurred and the invasive forms of Candida, i.e. germ tubes and pseudomycelium, also developed. Neither by different carbohydrates and concentration of nutrients in the culture medium nor by changing the flow rate the growth of Candida could be influenced. Excessive overgrowth was triggered by a sufficient oxygen supply.

Aerobiosis↗
PubMed1994

[Protein fingerprinting as a method for strain-specific differentiation of technologically useful Lactobacillus strains from clinical isolates].

Lactobacilli are often used in products of animal origin because of their technological properties and as protective cultures against pathogenic microorganisms, however they are supposed to be related to human infections as well. Therefore 39 strains of species that are in biotechnological usage, including the type strains, and some clinical isolates were investigated. 9 strains of L. acidophilus, 7 of L. gasseri and 23 strains of L. rhamnosus were tested. Biochemical and physiological properties were proved by classical tests. Analysis of the total soluble cytoplasmatic protein patterns was performed with diamine silver staining, a technique not previously applied to lactobacilli. Classical tests were able to confirm all strains as belonging to one of the three species. Analysis of protein patterns allowed to differentiate between strains of the same species. In case of L. acidophilus biotechnologically used strains and clinical isolates were clustered separately. L. rhamnosus formed three clusters. SDS-PAGE of proteins together with diamine silver staining seems to be helpful to detect intra-species differences. It was stated, that technologically used strains of lactobacilli could clearly be differentiated from another and also from clinical isolates.

Animals↗
PubMed1992

Expression of chimeric neo-Rev response element sequences interferes with Rev-dependent HIV-1 Gag expression.

Recombinant plasmids containing reiterated human immunodeficiency virus type 1 (HIV-1) Rev response element (RRE) sequences were constructed to suppress Rev-dependent HIV-1 Gag expression. The mammalian expression vectors pMAMneo containing one, three, or six repeats of the RRE sequence were cotransfected with a HIV-1 HTLV-IIIB proviral DNA into HeLa cells. All three RRE expression plasmids reduced replication of HIV-1 with similar efficacy. Furthermore, the chimeric expression vector pCMV neoRRE6 x ----(containing six copies of the RRE sequence) was used to establish HeLa cell lines constitutively expressing RRE. A plasmid encoding a Rev-dependent HIV-1 p24 Gag protein was cotransfected with the wild-type Rev expression plasmid into three different RRE-expressing HeLa cell lines. p24 Gag protein production in the culture supernatants of the HeLaneoRRE cells was compared with two neo-expressing cell lines. Although all cell lines (HeLaneoRRE, HeLaneo) displayed similar transfection efficiencies, p24 Gag protein synthesis was markedly reduced in the RRE-expressing cell lines in comparison to the control cells.

Base Sequence↗
PubMed1992

Technique for training schizophrenic patients in illness self-management: a controlled trial.

OBJECTIVE: To determine whether schizophrenic outpatients receiving low-dose neuroleptic therapy could learn and retain complex information and skills related to self-management of their illness, a novel technique of teaching, using cognitive and behavioral methods, was designed to compensate for the patients' learning disabilities. METHOD: The subjects were 41 patients with DSM-III-R schizophrenia who were receiving constant maintenance neuroleptic drug therapy. They were randomly assigned to structured, modularized skills training or to supportive group psychotherapy. RESULTS: The patients who received skills training made significant gains in each of the areas taught, while those participating in group therapy did not. The skills learned during training were retained without significant erosion over a 1-year follow-up period. CONCLUSIONS: The effectiveness of modularized teaching of illness self-management skills to schizophrenic patients appears to be largely independent of baseline psychology and symptom improvement. Such an approach is useful for overcoming or compensating for the enduring cognitive and information processing deficits commonly found in schizophrenia.

Activities of Daily Living↗
PubMed1991

Formation of new muscle fibres and tumours after injection of cultured myogenic cells.

We examined the effects of implantation of cultured myogenic cells from a permanent cell line into soleus muscles of histocompatible adult mice. Myogenic cells (10(6) or 10(4)) were implanted into intact muscles, muscles frozen with liquid nitrogen, paralysed with botulinum toxin or reinnervated after long-term (seven months) denervation. Formation of numerous muscle fibres in myogenic cell-injected muscles raised the total number of fibres up to ten times above control by four weeks. Larger effects were found in freeze-damaged than in paralysed muscles. The new fibres had small calibers, considerable length (greater than 1.3 mm, maximum distance over which serial sections were made), were multinucleated and were oriented parallel to the large-diameter fibres of the host muscles. In some experiments beta-galactosidase, introduced into myogenic cells via retroviral transfection, was detected in small and large muscle fibres 4-20 weeks after implantation, indicating survival of the grafted cells and formation of mosaic (host-donor) and new fibres of donor origin. Muscle weight increased significantly and, rather surprisingly, a parallel increase was found in isometric tetanic tension of isolated nerve-muscle preparations; thus tension per mg muscle tissue was not different from normal. By eight weeks reduction of acetylcholine sensitivity and down-regulation of neural cell adhesion molecule to normal were observed, indicating that synaptic transmission at the new fibres was mature. After different periods of time (5-20 weeks, depending on the subclone used) tumours developed in most but not all injected limbs (37 out of 39). The tumours were destructive to the muscles and were classified as rhabdomyosarcomas. Prior to tumour formation, neural cell adhesion molecule positive cells reappeared in the muscles; since the myogenic cells initially produced differentiated muscle fibres, it appears that malignant growth is induced by factors in vivo. Thus, at present the outcome of such implantation is unpredictable.

Acetylcholinesterase↗
PubMed1991

[The categorization of mandibular growth potential by Petrovic, Lavergne and Stutzmann].

The results of the study show whether the classification of mandibular growth potential, as proposed by Petrovic, Lavergne and Stutzmann has any influence on the treatment with a function regulator. X-rays of 140 class II patients were analysed after a treatment time of approximately 2 years. In comparison with 133 class II children without any treatment, a significant increase of mandibular length was observed in almost all children treated. There was no significant difference in the increase of mandibular length between category 2 (low growth potential) and category 5 (high growth potential).

Activator Appliances↗
PubMed1991

trans-activation of the HIV-1 LTR by the HIV-1 Tat and HTLV-I Tax proteins is mediated by different cis-acting sequences.

Human immunodeficiency virus type 1 (HIV-1) gene expression is regulated by viral and cellular factors interacting with cis-elements located in the retroviral long terminal repeat (LTR). In this report we analyzed HIV-1 LTR-specific regulatory sequences responsive to the HIV-1 Tat and HTLV-I Tax trans-activator proteins. Our results indicate that the Sp1 binding sites in the HIV-1 LTR are crucially involved in Tat-mediated gene expression in human Jurkat T-cells whereas they are dispensable for HTLV-I Tax-induced activation. In contrast, the NF-kB binding sites within the HIV-1 LTR are essential for Tax-mediated transcription but had only marginal effect on Tat-induced reporter gene expression.

Animals↗