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P Hoffmann

Publications and source records attributed to P Hoffmann.

At least 55 records · Page 3Linked to original sources
PubMed2001

Epithelial cell-derived components induce transforming growth factor-alpha mRNA expression and epithelial cell proliferation in vitro.

BACKGROUND: Epidermal growth factor (EGF) and transforming growth factor (TGF)-alpha protect the gastrointestinal mucosa against injury. In response to mucosal injury TGF-alpha, but not EGF, is locally increasingly expressed in the mucosa of the rat colon and stomach 4-8 h after injury. The aim of our present study was to characterize the possible signal for the induction of TGF-alpha expression. METHODS: Monolayers of the non-transformed intestinal epithelial cell (IEC)-6 and IEC-18 lines were harvested, homogenized and shock-frozen at -80 degrees C for 1 h. Cell cultures of intact IEC-6 or IEC-18 cells were exposed to these cell homogenates and modulation of epithelial cell migration and proliferation was evaluated using standardized procedures as described previously. TGF-alpha mRNA expression in the exposed epithelial cell monolayers was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) and normalized to the expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). RESULTS: The proliferation of IEC-6 and IEC-18 epithelial cell monolayers was significantly inhibited if epithelial cell homogenates of 2000 cells/ml or more, and significantly induced if homogenates of less than 2000 cells/ml, were applied to the medium of the monolayers in vitro. In proliferating epithelial cells, a significant two-fold increase in TGF-alpha mRNA expression was obtained at 48 h and 72 h after application of the cell homogenates. The homogenate-induced epithelial cell proliferation was completely abolished after preincubation of the epithelial cell homogenates with neutralizing monoclonal anti-TGF-alpha antibodies. No effect on epithelial cell migration was noticed after application of epithelial-cell homogenates to the cell cultures. CONCLUSIONS: Epithelial cell-derived components induce TGF-alpha mRNA expression and TGF-alpha-dependent cell proliferation of intact epithelial cells. We hypothesize that epithelial cell interaction bears one of the possible signals for the increased TGF-alpha mRNA expression after mucosal injury.

Animals↗
PubMed2001

Chronic anterior compartment syndrome and deep peroneal nerve function.

OBJECTIVE: We hypothesized that athletes with chronic anterior exertional compartment syndrome (CAECS) would demonstrate an impairment in deep peroneal nerve function, as determined by electrodiagnostic studies or neuromuscular examination, either at baseline as compared with control athletes or after exercise. DESIGN: Prospective, controlled study comparing athletes with CAECS to asymptomatic athletes. SETTING: Outpatient, academic practice. PARTICIPANTS: Ten athletes with CAECS were recruited sequentially over 1 year from an outpatient academic practice; diagnosis was confirmed by history, physical examination, and compartment pressure testing. Ten similarly aged control athletes were recruited from the surrounding facility. INTERVENTION: Repetitive dorsiflexion exercise to the point of typical symptoms (CAECS subjects) or fatigue (control subjects). MAIN OUTCOME MEASURES: Deep peroneal nerve conduction study velocity and amplitude; neuromuscular examination in the deep and superficial peroneal distributions. RESULTS: Control subjects demonstrated a significant increase in peroneal motor amplitudes postexercise as compared with preexercise (6.3 +/- 2.2 mV preexercise to 8.2 +/- 3.1 mV postexercise; p = 0.033), but the CAECS subjects did not (8.8 +/- 2.6 to 8.9 +/- 2.1; p = 0.89). At baseline and postexercise, the subjects with CAECS demonstrated decreased vibratory sensation compared with the controls (p = 0.030 at baseline and 0.045 postexercise). CONCLUSIONS: Athletes with CAECS demonstrate a decreased postexercise potentiation of the peroneal motor amplitude and a mild impairment in vibratory sensation; these findings may contribute to their sense of poor foot and ankle control. Further study is necessary before the absence of postexercise potentiation of the peroneal motor amplitude may be considered a diagnostic sign of CAECS.

Adolescent↗
PubMed2001

Extraperitoneal laparoscopic radical prostatectomy. Results after 50 cases.

INTRODUCTION: After an initial experience using transperitoneal laparoscopic radical prostatectomy as described by Vallancien and Guillonneau, we developed a pure extraperitoneal approach. This approach seems more comparable to the open technique and avoid potential risks of specific complications due to the transperitoneal approach. We evaluated the perioperative parameters (blood loss, operating time, transfusion rate) and postoperative results (oncological results, continence and potency) after our first 50 cases. MATERIAL AND METHOD: Between September 1999 and September 2000, we performed 50 laparoscopic radical prostatectomy. On average, patients were 63.3 years old (range 47-71), had preoperative mean PSA values of 9.14 ng/ml (1.1-23). Median Gleason score was 6 (4-10) with 2.5 (1-6) positive biopsies for a mean prostate volume of 40 cm(3) (17.5-95.0). Clinical stage was T1, T2a, T2b and T3 in 46.3, 41.5, 9.8 and 2.4% of the cases, respectively. We used a pure extraperitoneal approach and we performed a descending technique starting with the dissection at the bladder neck. The seminal vesicles dissection is comparable to the open approach. RESULTS: 42 extraperitoneal and 8 transperitoneal procedures were performed (2 in the initial experience, 3 because of previous abdominal surgery and 3 because of incidental peritoneal opening). Mean operative time was 317 min, mean blood loss 680 cm(3), transfusion rate of 13%. 1 patient/50 was converted to an open procedure. Pathological stage was pT1a, pT2a, pT2b, pT2c, pT3a and pT3b in 2.2, 8.5, 42.5, 2.2, 34 and 10.6% of cases, respectively. Positive surgical margins were observed in 22% of cases. The potency rate after neurovascular bilateral bundle preservation was 43% at 3 months (n = 7) and 67% at 6 months and (n = 6) without any further treatment. The continence rate (no pad) was 39% at 3 months and 85% at 6 months. Detectable postoperative PSA at 3 month was observed in 2 patients only. Two major complications occurred: one acute transient renal failure one uretrorectal fistula at day 20. CONCLUSIONS: The extraperitoneal laparoscopic radical prostatectomy results seem comparable to transperitoneal laparoscopic radical prostatectomy or open surgery. This approach is reproducible and seems to avoid the potential risks of intraperitoneal injury. Long-term follow up and comparative series are however necessary to further evaluate these new techniques.

Aged↗
PubMed2001

Induction of soluble antitumoral mediators by synthetic analogues of bacterial lipoprotein in bone marrow-derived macrophages from LPS-responder and -nonresponder mice.

Macrophage-dependent antitumoral activity is partly mediated by soluble factors including cytokines, reactive-oxygen intermediates (ROIs), and reactive-nitrogen intermediates (RNIs). Activation of macrophages for tumor cytotoxicity can be achieved with various bacterial compounds, such as lipopolysaccharides (LPSs), muramyl-dipeptides, and lipopeptides. We studied the production and release of oxygen radicals, nitric oxide, and tumor necrosis factor alpha (TNF-alpha) by bone marrow-derived macrophages (BMDMs) of different mouse inbred strains after they were stimulated with the lipopeptide P3CSK4, a water-soluble synthetic analogue of the lipidated N terminus of bacterial lipoprotein. The lipopeptide was able to induce a strong, long lasting release of oxygen radicals in BALB/c mouse macrophages. Furthermore, it induced nitric oxide release from BMDMs of several mouse strains (BALB/c, C57Bl/6, C57Bl/10ScSn, Sv129, NMRI, and LPS-nonresponder C57Bl/10ScCr). Stimulation with P3CSK4 also resulted in comparable production of TNF-alpha in LPS-responder and nonresponder BMDMs from C57Bl/10ScSn mice and C57Bl/10ScCr mice, respectively. All three antitumoral mediators reached functional levels or concentrations as shown by the strong cytostatic/cytotoxic activity of lipopeptide-activated macrophages for the cell lines Abelson 8-1, M12.5/P815, and L929, which are sensitive to ROIs, nitric oxide, and TNF-alpha, respectively. We found that synthetic lipopeptides can induce the secretion of effective levels of soluble tumor-cytotoxic/cytostatic mediators in BMDMs of LPS-responsive and, of particular interest, also of LPS-unresponsive mice. This result could indicate that the highly effective bacterial-macrophage activators P3CSK4 and LPS use different receptors and/or different intracellular signal transduction pathways.

Acridines↗
PubMed2000

Chiral capillary electrophoresis as predictor for separation of drug enantiomers in continuous flow zone electrophoresis.

Separation of the enantiomers of chlorpheniramine and methadone in acidic buffers containing carboxymethyl-betacyclodextrin (CMCD) as chiral selector was investigated by capillary zone electrophoresis. For a range of pH and CMCD concentrations, the mobility difference and resolution of the enantiomers were determined. Then, conditions known to provide well resolved enantiomers and optimized chiral separation were applied to chiral continuous flow electrophoresis. In that approach, a thin film of fluid flowing between two parallel plates is employed as carrier for electrophoresis. The electrolytes and the sample are continuously admitted at one end of the electrophoresis chamber and are fractionated by an array of outlet tubes at the other. The number of pure enantiomeric fractions obtained by chiral continuous flow electrophoresis was found to be directly dependent on the enantiomeric mobility difference. For racemic chlorpheniramine separated in a betaine-acetic acid buffer at a total throughput of 5 mg/h, complete enantiomeric separation is shown to require a mobility difference of about 3 x 10(-9) m2/V s. Furthermore, compared to the previous investigations with hydroxypropyl-beta-cyclodextrin, CMCD was found to permit improved fractionation of methadone enantiomers. With a total racemic drug throughput of about 15 mg/h, continuous flow zone electrophoresis processing with CMCD as chiral selector is shown to have the potential of providing pure enantiomers on a mg/h scale. The results indicate that chiral capillary zone electrophoresis data can be employed as predictor for preparative scale chiral separations based upon continuous flow zone electrophoresis.

Chlorpheniramine↗
PubMed2000

Comparative dynamics and location of chain spin-labelled sphingomyelin and phosphatidylcholine in dimyristoyl phosphatidylcholine membranes studied by EPR spectroscopy.

The dynamics and environment of sphingomyelin spin-labelled at different positions in the N-acyl chain have been studied in dimyristoyl phosphatidylcholine bilayer membranes by using electron spin resonance spectroscopy. Comparison was made with phosphatidylcholine spin-labelled on the sn-2 acyl chain in the same host membrane. Spin-labelled sphingomyelin was found to mix well with the host phosphatidylcholine lipids in both gel and fluid phase membranes. At 1 mol%, mutual spin-spin interactions are no greater than for spin-labelled phosphatidylcholine. In the fluid membrane phase, the effective chain order parameters and polarity-sensitive isotropic hyperfine coupling constants of spin-labelled sphingomyelin display a similar dependence on the position of labelling to those of spin-labelled phosphatidylcholine. The values of both parameters are, however, generally larger for sphingomyelin than for phosphatidylcholine at equivalent positions of acyl chain labelling. This difference is attributed to the different chain linkage of sphingo- and glycero-lipids, combined with an offset of approximately one C-atom in transbilayer register between the respective N-acyl and O-acyl chains. In the gel phase, differences in chain configuration between sphingomyelin and phosphatidylcholine are indicated by differences in spin label spectral anisotropy between the two lipids, which appears to reverse towards the terminal methyl chain end.

Dimyristoylphosphatidylcholine↗
PubMed2000

Enhancement of natural immunity seen after voluntary exercise in rats. Role of central opioid receptors.

Chronic voluntary exercise in wheels for 5 weeks in spontaneously hypertensive rats (SHR) augments in vivo natural killer (NK) cell cytotoxicity. Endogenous beta-endorphin is increased in cerebrospinal fluid after voluntary exercise in rats and we have recently shown that beta-endorphin administered i.c.v. augments NK cell mediated cytotoxicity in vivo in a similar way as chronic voluntary exercise. We have now further investigated the involvement of central opioid systems in the exercise-induced augmentation in natural immunity. Exercise consisted of voluntary running in wheels for 5 weeks. In vivo cytotoxicity was measured as clearance of injected 51Cr-labeled YAC-1 lymphoma cells from the lungs. The clearance of YAC-1 cells in vivo was significantly increased in runners as compared to sedentary controls. Selective delta, kappa, or mu-opioid receptor antagonists were administered i.c.v. with osmotic minipumps during the last 6 days of the 5 weeks of running. The delta-receptor antagonist naltrindole (40-50 microg/day) significantly but not completely inhibited the enhanced NK-cell cytotoxicity seen after 5 weeks of exercise. Neither the kappa-receptor antagonist nor-BNI or the mu-receptor antagonist beta-FNA influenced the augmentation in NK cell cytotoxicity. Nor-BNI per se significantly augments in vivo cytotoxicity, indicating some inhibiting effect on natural immunity that could be mediated through the kappa-opioid receptor. Our data suggest the involvement of central delta-opioid receptors in the enhancement of natural cytotoxicity seen after chronic voluntary exercise.

Animals↗
PubMed2000

Graphite furnace-atomic absorption spectrophotometric determination of palladium in soil.

A new and sensitive procedure for the graphite furnace-atomic absorption spectrophotometric (GF-AAS) determination of Pd in soil at nanogram level is described. The method is based on prior separation and enrichment of the metal as Pd(II)-SnCl3- -N-butylacetamide (BAA) complex into 1-pentanol (PN) by solvent extraction method. The value of the molar absorptivity of the complex in three solvents, i.e. ethyl acetate, 1-pentanol, chloroform, lie in the range of (0.70-2.75) x 10(4) L mol(-1) cm(-1) at lambda(max) 360-440 nm. The metal could be enriched into organic solvent, i.e. PN, up to 10-folds. The sensitivity (A = 0.0044) of the method in the term of the peak height was 0.5 ng Pd/mL of the aqueous solution at an enrichment factor (EF) of 5. Optimization of analytical variables during enrichment and GF-AAS determination of the metal are discussed. The method has been applied for the analysis of Pd to soil samples derived from roads and highways in Germany.

Palladium↗
PubMed2000

Oxygen determination in calcium fluoride by deuteron activation analysis.

Oxygen at trace level in calcium fluoride was determined by instrumental deuteron activation analysis based on the 16O(d,n)17F reaction. The irradiations were performed with 2.5 MeV deuterons for 60 s at currents ranging from 300 to 500 nA. The results obtained for powders and single crystals were compared.

Journal Article↗
PubMed2000

Bioleaching of heavy metal-contaminated sediments by indigenous Thiobacillus spp: metal solubilization and sulfur oxidation in the presence of surfactants.

The efficiency of surfactant application to improve or inhibit metal solubilization and sulfur oxidation kinetics during the bioleaching of heavy metal-contaminated sediments was studied in suspension-leaching experiments. The river sediment used contained large amounts of fine particles and organic matter. Three types of surfactants were tested: sodium dodecylsulfate (SDS), a C(12/14)-alkanolethoxylate (Präwozell F1214/5N), and a wettable sulfur (Netzschwefel 80 WP). Adding 10 mmol SDS/l led to transient inhibition of acidification, metal solubilization and sulfur oxidation. Inhibiting bioleaching for just 14 days required about ten times more SDS than the amount used for mine waste mitigation. The use of Präwozell resulted in poor inhibition; and using of wettable sulfur did not improve leaching efficiency. The bulk of these surfactants was sorbed onto the solid particles immediately on application, while the remainder in the aqueous phase disappeared within a few days.

Environmental Pollutants↗
PubMed2000

Lipopeptides as immunoadjuvants and immunostimulants in mucosal immunization.

In previous studies we have shown that lipopeptides constitute potent immunoadjuvants in mice, rabbits and other species: in parenteral immunization, lipopeptide adjuvants were comparable, or in some cases superior to Freund's adjuvant, and were devoid of the side effects of this additive. Here we demonstrate that lipopeptides also constitute adjuvants for mucosal immunizations. The serum antibody responses against the wheat storage protein gliadin, the bee venom constituent melittin, or the hen egg protein ovalbumin could in most cases be enhanced more than 100-fold by the lipopeptide P3CSK4, applied via the nasal route. An enhanced specific antibody level could also be detected in supernatants of cell cultures prepared from spleens, Peyer's patches, lungs and mesenteric lymph nodes of immunized mice. Moreover, the lipopeptide P3CSK4 enhanced chemiluminescence in mouse spleen cells and peritoneal macrophages in vitro, indicating a macrophage-activating effect. Finally, nasal application of lipopeptide increased protection against a lethal infection of influenza. Our findings are of importance for the improvement of immunizations and might lead to more effective vaccines.

Adjuvants, Immunologic↗
PubMed2000

Immunostimulation by bacterial components: I. Activation Of macrophages and enhancement of genetic immunization by the lipopeptide P3CSK4.

Synthetic lipopeptides derived from the N-terminus of bacterial lipoprotein constitute potent macrophage activators and polyclonal B-lymphocyte stimulators. They are also efficient immunoadjuvants in parenteral, oral and nasal immunization either in combination with or after covalent linkage to an antigen. Here we show how alterations in the molecular structure influence their biological properties indicating P3CSK4 as one of the most active members of a lipopentapeptide fatty acid library. This compound resulted in a most pronounced macrophage stimulation as indicated by NO release, activation of NFkappaB translocation, and enhancement of tyrosine protein phosphorylation. Furthermore, P3CSK4 activates/represses an array of at least 140 genes partly involved in signal transduction and regulation of the immune response. Finally we have evidence that P3CSK4 constitutes an effective adjuvant for DNA immunizations, especially increasing weak humoral immune responses. Our findings are of importance for further optimizing both conventional and genetic immunization, and for the development of novel synthetic vaccines.

Adjuvants, Immunologic↗
PubMed2000

Generation of antibodies directed against the low-immunogenic peptide-toxins microcystin-LR/RR and nodularin.

The preparation of antibodies against the liver toxin microcystin, as described here, is of major importance for its detection and purification in food and water, and for a therapeutic approach to neutralize the toxin by passive immunization. Microcystin-LR (MLR) and microcystin-RR (MRR) were purified from cyanobacterial cell materials by extraction, Sephadex LH-20-, ODS silica gel-, ionic exchange and RP-HPLC-chromatography. In order to reduce the toxicity for parenteral administration, microcystins were coupled by the carbodiimide method to poly-L-lysine (PLL(50.000)). Mice and rabbits were immunized with the conjugates in the presence of two lipopeptide immunoadjuvants (P(3)CSK(4) and P(3)CS-T(h)). High MLR-specific antibody levels were observed after parenteral coadministration of antigen and lipopeptides, whereas no anti-MLR antibodies were obtained with free microcystin or the microcystin-PLL(50.000)-conjugate in the absence of lipopeptide. In oral immunization, coadministration of antigen and adjuvants resulted in an accelerated development of anti MLR-specific antibodies and high antibody levels. Using the antisera, we could detect different microcystins and nodularin down to a concentration range of 10-50 ng/ml by a competitive inhibition ELISA; detection of microcystins in crude cell preparations was also possible. Furthermore, microcystins from different sources could be detected and discriminated from cyclic cyanopeptolines.

Administration, Oral↗
PubMed2000

Increased expression of epidermal growth factor-receptor in an experimental model of colitis in rats.

BACKGROUND: Epidermal growth factor and related proteins share some structural homology and bind to one common receptor. We have shown previously that exogenously applied EGF protects colonic mucosa against injury in an experimental model of colitis in rats and that the endogenously expressed ligands for the EGF-receptor are predominantly transforming growth factor alpha precursors. The aim of our present study was to evaluate the EGF-receptor expression in response to mucosal injury in the same model of colitis. METHODS: The trinitrobenzene sulphonic acid (TNBS)/ethanol-induced model of colitis in rats was used and EGF-receptor expression was evaluated using ribonuclease protection assay and Western blot analysis. The extent of mucosal injury and inflammation was characterized by using a microscopic and macroscopic damage score and by estimation of the myeloperoxidase activity in colonic specimens. RESULTS: Irritation of the colonic mucosa leads to severe colonic inflammation with tissue oedema, erosions and mucosal ulcers and to a significant increase in myeloperoxidase activity expressed by neutrophil granulocytes and macrophages. A significant increase in EGF-receptor mRNA expression was obtained at 8-24 h followed by an increased expression of the EGF-receptor protein at 1-5 days after the induction of colitis. On Western blot analysis only one immunoreactive band with a molecular weight of approximately 170 kDa was detected. CONCLUSIONS: Mucosal inflammation leads to a significant increase in the EGF-receptor expression in the early phases of colitis. These findings support our hypothesis that EGF and related proteins and their common receptor play a pivotal role in mucosal defence and repair.

Actins↗
PubMed2000

The significance of intensity and duration of exercise on natural immunity in rats.

PURPOSE: The purpose of this study was to examine a) the relationship between running distance (km x d(-1)) and b) the duration of exercise training in weeks on the effects on natural immune function in spontaneously hypertensive rats (SHR). METHODS: Exercise consisted of voluntary running in wheels for 5 or 11 wk. In vivo cytotoxicity was measured as clearance of injected 51Cr-labeled YAC-1 lymphoma cells from the lungs. RESULTS: Increased in vivo cytotoxicity was seen after 5 wk of exercise (P < 0.001) but not after voluntary exercise for 11 wk. If the wheels were locked 3 d x wk(-1) during the last 6 wk of running, thus restricting the exercise to 4 d x wk(-1), the exercise-induced immunoenhancement seen after 5 wk of exercise was maintained also after 11 wk of exercise. When compared with the sedentary controls after 5 wk of exercise, all runners regardless of running distance exhibited significantly higher in vivo clearance of tumor cells from the lungs, and no overall significant correlation was seen between running distance and retained radioactivity. However, the lowest activity runners (< 4 km x d(-1)) exhibited significantly lower in vivo clearance of tumor cells from the lungs when compared with animals running more than 4 km x d(-1). CONCLUSION: We conclude that the duration of exercise training, and to some extent the running distance, has significant effects on the training-induced increase in natural immune function in rats. Furthermore, we conclude that a resting or recovery period during long-term exercise training is important to maintain the immunoenhancing effects in response to exercise.

Animals↗
PubMed2000

NO-Mediated aromatic nitration during decomposition of phenolic S-nitrosothiols in non-aqueous aerobic medium.

Five novel S-nitrosothiol compounds (6-10) derived from L-cysteine were generated in solution and their decomposition rate was followed by UV spectroscopy. In acetonitrile, compounds 9 and 10 were the most stable of this series with a half-life of 24 h. The final organic decomposition products of the five S-nitrosothiols were also analysed. Derivatives 8, 9, and 10, possessing a phenolic hydroxyl group, afforded an unexpected decomposition pathway, with nitration of aromatic ring occurring in non-aqueous media. A mechanism involving a phenoxy radical seems to be implicated.

Aerobiosis↗