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H Lindner

Publications and source records attributed to H Lindner.

At least 37 records · Page 2Linked to original sources
PubMed1998

Substrate and sequential site specificity of cytoplasmic histone acetyltransferases of maize and rat liver.

The cytoplasmic B-type histone acetyltransferase was purified to apparent homogeneity from maize embryos. We established a novel protocol for easy large-scale preparation of acetylated core histone species, using preparative acetic acid-urea-Triton PAGE. The pure maize histone acetyltransferase B was highly specific for histone H4 under various assay conditions, modifying H4 up to the di-acetylated isoform. Only non-acetylated H4 isoform was accepted as substrate, whereas mono-acetylated H4 could not be further acetylated. The enzyme selectively acetylated lysines 12 and 5 in a sequential manner. The same results were obtained with a partially purified cytoplasmic histone acetyltransferase of rat liver. Protein sequencing results were supported by immunological characterization of acetylated H4 subspecies with site-specific H4-acetyllysine antibodies.

Acetylation↗
PubMed1998

Human and porcine aminoacylase I overproduced in a baculovirus expression vector system: evidence for structural and functional identity with enzymes isolated from kidney.

Aminoacylase I (EC 3.5.1.14) is one of the most abundant enzymes in the cortical region of mammalian kidney. Both the porcine and the human enzyme were overexpressed using baculovirus expression vector systems and purified by hydrophobic interaction chromatography and anion-exchange chromatography. The resulting preparations were analyzed for structural and functional identity with the corresponding enzymes isolated from kidney. The dansyl method as well as mass spectroscopy confirmed N-terminal blocking. For the porcine enzyme, atomic absorption spectroscopy yielded the correct metal content (one zinc per subunit). Kinetic analyses showed identical Km values for the expression products and the enzymes isolated from kidney. By contrast, the porcine enzyme when overexpressed in Escherichia coli had a much lower specific activity. Comparative substrate specificity studies with natural and recombinant human aminoacylase and 16 different N-acetyl-L-amino acids showed that, among the derivatives of proteinogenic amino acids, N-acetyl-L-methionine was the best substrate, followed by acetylated glutamate, leucine, alanine, and valine. These amino acids are also the most abundant residues at the N-termini of acetylated proteins. This suggests that kidney aminoacylase may be involved in the salvage of amino acids by hydrolyzing acetyl amino acids released from proteins.

Acetylation↗
PubMed1998

Ceramic coagulation tip for interstitial thermoablation of the prostate: first experiments.

A direct electrically heated ceramic coagulation tip for interstitial thermoablation has been developed. Both the coagulation tip and a laser system (Medilas 4060) were tested in vitro to compare their efficacies. We have obtained coagulation necroses of similar sizes. The electrical coagulation tip as opposed to laser coagulation is a new therapeutic option for the therapy of high risk patients with symptomatic benign prostatic hyperplasia. Because of the materials used and the principle of heating involved, certain economic and safety advantages over the laser system are offered.

Animals↗
PubMed1998

Loss of myocardial capillary endothelial-cell alkaline phosphatase (ALP) activity in primary endothelial cell culture.

Primary cultures of rat myocardial capillary endothelial cells were established and characterized. A range of typical endothelial cell-specific markers were retained in vitro. Cell kinetic studies in confluent endothelial-cell cultures in vitro revealed a roughly 50-fold increase in the proportion of cells in s-phase, indicating a very considerable shortening of cell turnover time, compared to in vivo conditions. Alkaline phosphatase enzyme activity and encoding mRNA are strongly expressed in myocardial capillary endothelial cells in vivo, but were not detectable in vitro. This was true in cell cultures from two strains of rat, which revealed significantly different enzyme expression levels in vivo. In co-cultures of pericytes and endothelial cells, positive ALP enzyme reaction was detected in pericytes, which in vivo show only very weak enzyme reactivity. Treatment of cell cultures with </=10 M retinoic acid had no effect in pure endothelial cell cultures, but did increase ALP expression of pericytes in co-cultures. The observation of a loss of endothelial ALP expression in vitro supports other in vitro as well as our own in vivo observations, indicating a negative correlation of ALP expression and proliferative activity of endothelial cells.

Alkaline Phosphatase↗
PubMed1997

Effects of reagent and enzymatically generated hypochlorite on physicochemical and metabolic properties of high density lipoproteins.

Myeloperoxidase (MPO), a protein secreted by activated phagocytes, may be a potential candidate for the generation of modified/oxidized lipoproteins in vivo via intermediate formation of HOCl, a powerful oxidant. During the present study, the effects of reagent NaOCl and OCl- generated by the MPO/H2O2/Cl- system on physicochemical and metabolic properties of high density lipoprotein (HDL) subclass 3 (HDL3) were investigated. Up to a molar oxidant:lipoprotein ratio of approximately 30:1, apolipoprotein A-I (apoA-I), the major HDL3 apolipoprotein component, represented the preferential target for OCl- attack (consuming 35-76% of the oxidant), thereby protecting HDL3 fatty acids (consuming between 17 and 30% of the oxidant) against OCl--mediated modification. At molar oxidant:HDL3 ratios >/= 60:1, we have observed pronounced consumption of HDL3 unsaturated fatty acids with concomitant formation of fatty acid chlorohydrins. Modification of HDL3 in the presence of the MPO/H2O2/Cl- system resulted in amino acid oxidation in a manner comparable with that found with reagent NaOCl only. Treatment of HDL3 with reagent NaOCl as well as modification by the MPO/H2O2/Cl- system resulted in significantly enhanced turnover rates of HDL3 by mouse peritoneal macrophages, an effect that was not a result of HDL3 aggregation as judged by dynamic and static light-scattering experiments. In comparison with native HDL3, the degradation by macrophages was enhanced by 4- and 15-fold when HDL3 was modified with reagent NaOCl or the MPO/H2O2/Cl- system. Finally, the ability of HDL3 to promote cellular cholesterol efflux from macrophages was significantly diminished after modification with reagent NaOCl. Collectively, these results demonstrate that the modification of HDL3 by hypochlorite (added as reagent or generated by the MPO/H2O2/Cl- system) transformed an antiatherogenic lipoprotein particle into a modified lipoprotein with characteristics similar to lipoproteins commonly thought to initiate foam cell formation in vivo.

Animals↗
PubMed1997

Influence of bacterial endotoxin on radiation-induced activation of human endothelial cells in vitro and in vivo: interleukin-10 protects against transendothelial migration.

To extend previous studies on the anti-inflammatory role of interleukin (IL)-10 in vivo, mice pretreated with IL-10 were subjected to ionizing radiation (IR), lipopolysaccharide (LPS), or both and assessed for the expression of the intercellular adhesion molecule 1 (ICAM-1) in immunohistochemical analyses. IL-10 was able to almost fully protect LPS+IR-treated animals against ICAM-1 up-regulation. Because LPS and IR also increased adhesion of peripheral blood mononuclear cells, transendothelial migration assays were performed to investigate the functional significance of these findings. IR was found to induce transendothelial migration, and this effect could be enhanced by cotreatment with LPS, in the same fashion as peripheral blood mononuclear cell adhesion. Also in this system, IL-10 proved to act as a potent LPS antagonist. Finally, in vivo immunohistochemical analyses revealed an infiltration of CD3+ T lymphocytes into organs that were the target of transplant-related complications after LPS+IR treatment. This infiltration could also be completely reversed by IL-10 pretreatment.

Animals↗
PubMed1997

Application of hydrophilic-interaction liquid chromatography to the separation of phosphorylated H1 histones.

A new two-step high-performance liquid chromatography (HPLC) procedure has been developed to separate modified histone H1 subtypes. Reversed-phase (RP) HPLC followed by hydrophilic-interaction liquid chromatography (HILIC) was used for analytical and semi-preparative scale fractionation of multi-phosphorylated H1 histone subtypes into their non-phosphorylated and distinct phosphorylated forms. The HILIC system utilizes the weak cation-exchange column PolyCAT A and an increasing sodium perchlorate gradient in a methanephosphonic acid-triethylamine buffer (pH 3.0) in the presence of 70% (v/v) acetonitrile. The identity and purity of the individual histone subfractions obtained was assayed by capillary electrophoretic analysis. The results demonstrate that application of the combined RP-HPLC-HILIC procedure to the analysis and isolation of modified H1 histone subtypes provides an innovative and important alternative to traditional separation techniques that will be extremely useful in studying the biological function of histone phosphorylation.

Acetonitriles↗
PubMed1997

Peripheral blood mononuclear cells induce programmed cell death in human endothelial cells and may prevent repair: role of cytokines.

Human umbilical vein endothelial cells (HUVECs) undergo programmed cell death (apoptosis) after coculture with peripheral blood mononuclear cells (PBMCs) preactivated by ionizing radiation (IR) or by bacterial endotoxin (lipopolysaccharide [LPS]). Cell-to-cell contact-mediated apoptosis could be blocked in both cases by anti-tumor necrosis factor-alpha (anti-TNF-alpha) monoclonal antibody MAK195 and also by the antagonistic cytokine interleukin-10 (IL-10). Cell-free PBMC supernatants from both preactivation treatments were sufficient to trigger endothelial apoptosis. In contrast, MAK195 and IL-10 were found to be ineffective in this system, suggesting a TNF-alpha-independent mechanism. However, N-Acetylcystein, an antioxidant, fully abrogated programmed cell death mediated by the supernatant of IR-treated PBMCs, but not of LPS-treated PBMCs. Additionally, we found that coculture and cell-free supernatants of preactivated as well as untreated PBMCs caused cell cycle arrest in proliferating EC in G(0/1), which could be relieved by IL-10, but not by anti-TNF-alpha. Further analysis showed that transforming growth factor-beta, which was constitutively expressed in the supernatant of PBMCs, namely lymphocytes, was responsible for this. These data suggest a pathophysiologic model in which preactivated PBMCs cause EC damage and may prevent blood vessel repair by arresting the proliferation of ECs. This could contribute to the understanding of various clinical endothelial complications that occur after irradiation as well as in cases of endotoxemia or related inflammatory states.

Apoptosis↗
PubMed1997

Differential modulation of IL-1-induced endothelial adhesion molecules and transendothelial migration of granulocytes by G-CSF.

Granulocyte colony stimulating factor (G-CSF) is widely used for mobilization of haemopoietic stem cells into the peripheral blood. However, little is known about the mechanisms involved in mobilization and the immune modulatory effects of this growth factor. In this report we show that G-CSF down-regulated intercellular adhesion molecule 1 (ICAM-1) induced by Interleukin-1 (IL-1) on human endothelial cells. Interestingly, the G-CSF-mediated down-modulation of IL-1-induced ICAM-1 appeared to be biphasic. In pharmacological concentrations (> 300 ng/ml), and in dose ranges of plasma G-CSF levels above that of nonfebrile healthy individuals (30 pg/ml), a significant decrease in surface ICAM-1 could be observed. This could be explained, at least in part, by an increased autocrine G-CSF production by endothelial cells in response to IL-1 and exogenous G-CSF. In contrast to ICAM-1, IL-1-triggered VCAM-1 expression was superinduced by G-CSF with the optimal concentration of 30 pg/ml. To evaluate the functional significance of these findings, 51Cr adhesion assays with peripheral blood mononuclear cells (PBMC) or granulocytes known to lack the VCAM-1 counter-receptor very late antigen 4 (VLA-4) and IL-1-stimulated endothelial cells, in the presence or absence of G-CSF, were performed. G-CSF could not inhibit the IL-1-induced adhesion of PBMC to endothelial cells, which may be due to the differential adhesion molecule modulation. In contrast, granulocyte adhesion induced by IL-1 could effectively be blocked by co-incubation with G-CSF. Finally, G-CSF also inhibited transendothelial migration of granulocytes through IL-1-activated endothelial cells in a concentration-dependent manner.

Cell Adhesion↗
PubMed1997

Comparison of self-assessment of premenstrual symptoms with scores on the modified Menstrual Distress Questionnaire.

Premenstrual symptoms were assessed in a sample of 267 women (M age 31.4 yr.) using a single self-identification question and the modified Menstrual Distress Questionnaire of Clare and Wiggins. The-self-identification question asked to what degree the women experienced premenstrual symptoms. The responses were 34 (13%) for none, 116 (43%) for slight, 99 (37%) for moderate, and 18 (7%) for severe. The mean score on the questionnaire was 23.5 (SD = 17.5). Correlations indicated significant relationships between self-identification and questionnaire scores (rho = .76, p < .001). When the women were classified according to Clare's (1983) criterion, almost a third of them assessed their symptoms differently, i.e., while they classified themselves as "nonsufferers" on the self-identification question, their responses on the questionnaire identified them as "sufferers."

Adult↗
PubMed1997

[Analysis of primary management of bladder malfunction in traumatic paraplegic patients].

UNLABELLED: Intermittent catheterisation is the demanded therapy of bladder paralysis during the spinal shock. We investigated the realisation of this concept. In 1994 after first treatment in other hospitals 97 patients were treated in the Thuringian Spinal Cord Centre Sülzhayn. The primary treatment of the paralysed bladder was: indwelling catheter: 44 patients (45.4%), suprapubic catheter: 30 patients (30.9%). Only 15 patients (15.5%) were catheterized intermittently. No urological treatment was carried out in seven cases. CONCLUSION: The primary treatment of bladder analysis in spinal cord injured patients has to be improved.

Adult↗
PubMed1997

Diagnostic value of natural fill cystometry in neurogenic bladder in children.

OBJECTIVE: Investigation of the diagnostic value of natural fill cystometry (NFC) in children with neurogenic bladder in comparison to conventional videocystometry (CVC). METHODS: We investigated 20 children (aged 6-11; 15 girls and 5 boys) with the following diagnoses: 6 myelomeningocele, 2 tethered cord syndrome, 1 syringomyelia, 1 Vater syndrome, 1 suprasacral spinal cord injury, 9 suspected neurogenic bladder. We carried out a NFC after completing standard diagnostic including a slow-filling CVC. RESULTS: All investigations were completed successfully. The investigation lasted 6-20.5 h (mean 11:15 h). We registered phases of sleep, waking consciousness and micturition. CVC findings were confirmed in 45%: normal bladder function was confirmed in 2 patients (10%), bladder hyperactivity was confirmed in 7 patients (35%). In 55% we obtained different findings on NFC in comparison to the slow-filling CVC: bladder hyperactivity was not confirmed in 2 (10%), detection of bladder hyperactivity was found in 4 children (20%) with normal bladder function on CVC, detection of bladder hyperactivity on NFC was found in 5 children (25%) with low-compliance bladder on CVC. In 45% of all children, NFC detected new findings compared with CVC diagnoses. In 10%, possible artifacts (e.g. due to catheterization) of CVC were recognized. CVC findings were confirmed in 45%. CONCLUSION: These results are preliminary but they suggest that this is a new diagnostic method for improving the diagnostic standard in the childhood neurogenic bladder.

Child↗
PubMed1997

[EMG surface polygraphy of the pelvic floor--description of functional changes after radical prostatectomy].

Urinary stress incontinence after radical prostatectomy could be cured by physiotherapy in a high percentage. The authors developed an investigation procedure for description of myoelectrical activity of pelvic floor with surface electrodes. 10 patients were studied 1 day before, 10 days and 6 months after radical prostatectomy. Significant changes of amplitude and frequency characteristics could not be found in rest and during the stationary intervals of maximal contraction. But after the operation in all patients changed the activation pattern within the interval of increasing muscle contraction. The mean and median frequency decreased significantly (Friedman-test, p < 0.001). This was interpreted as a problem of intramuscular coordination. After physiotherapy urinary incontinence was cured or improved. The typical activation pattern of dyscoordination was not more evident after 6 months.

Aged↗
PubMed1996

Influence of bacterial endotoxin on radiation-induced activation of human endothelial cells in vitro and in vivo: protective role of IL-10.

Previous work from our group has contributed to demonstrate the role of conditioning related release of proinflammatory cytokines in induction of acute graft-versus-host disease (GVHD) following allogeneic bone marrow transplantation (BMT). In the present report we show that ionizing radiation (IR) in a clinical relevant dose upregulates intercellular adhesion molecule 1 (ICAM-1) on cultured human microvascular endothelial cells (HMEC). Bacterial endotoxin (lipopolysaccharide, LPS) in a concentration corresponding to serum levels seen during clinical endotoxemia, is capable of further enhancing ICAM-1 expression on irradiated cells. Adhesion assays with freshly isolated peripheral blood mononuclear cells (PBMC) revealed that increased ICAM-1 on IR-treated endothelial cells led to an increased adhesion of PBMC. Again, this effect could be superinduced by LPS. Recombinant human interleukin 10 (IL-10), an antagonistic cytokine known to function as an LPS antagonist, was able to counteract the LPS-mediated enhancement of IR-triggered ICAM-1 induction and PBMC adhesion. In contrast, IL-10 could not inhibit irradiation caused effects. IL-10 seemed to interfere with the translocation of preformed intracellular ICAM-1 to the cell membrane. To investigate whether this superinductive function of IR and LPS on endothelial cells is of clinical relevance, mice were treated with total body irradiation (TBI) and inoculated with a single dose of LPS. Immunohistochemical analyses of murine tissues demonstrated that LPS superinduces IR-triggered ICAM-1 also in vivo. These findings may be of clinical importance as they suggest that the endothelium is activated after radiotherapy or TBI used for conditioning in bone marrow transplantation. The activated endothelium in turn may facilitate the accumulation of effector cells at sites of inflammation.

Animals↗
PubMed1996

Separation of acetylated core histones by hydrophilic-interaction liquid chromatography.

Hydrophilic-interaction liquid chromatography (HILIC) has recently been introduced as a highly efficient chromatographic technique for the separation of a wide range of solutes. The present work was performed with the aim of evaluating the potential utility of HILIC for the separation of postranslationally acetylated histones. The protein fractionations were generally achieved by using a weak cation-exchange column and an increasing sodium perchlorate gradient system in the presence of acetonitrile (70%, v/v) at pH 3.0. In combination with reversed-phase high-performance liquid chromatography (RP-HPLC) we have successfully separated various H2A variants and posttranslationally acetylated forms of H2A variants and H4 proteins in very pure form. An unambiguous assignment of the histone fractions obtained was performed using high-performance capillary and acid-urea-Triton gel electrophoresis. Our results demonstrate that for the analysis and isolation of modified core histone variants HILIC provides a new and important alternative to traditional separation techniques and will be useful in studying the biological function of histone acetylation.

Acetylation↗