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C Bolliger

Publications and source records attributed to C Bolliger.

14 recordsLinked to original sources
PubMed2001

In situ assessment of microbial sulfate reduction in a petroleum-contaminated aquifer using push-pull tests and stable sulfur isotope analyses.

Anaerobic microbial activities such as sulfate reduction are important for the degradation of petroleum hydrocarbons (PHC) in contaminated aquifers. The objective of this study was to evaluate the feasibility of single-well push-pull tests in combination with stable sulfur isotope analyses for the in situ quantification of microbial sulfate reduction. A series of push-pull tests was performed in an existing monitoring well of a PHC-contaminated aquifer in Studen (Switzerland). Sulfate transport behavior was evaluated in a first test. In three subsequent tests, we injected anoxic test solutions (up to 1000 l), which contained 0.5 mM bromide (Br-) as conservative tracer and 1 mM sulfate (SO4(2-)) as reactant. After an initial incubation period of 42.5 to 67.9 h, up to 1100 l of test solution/groundwater mixture was extracted in each test from the same location. During the extraction phases, we measured concentrations of relevant species including Br-, SO4(2-) and sulfide (S(-II)), as well as stable sulfur isotope ratios (delta 34S) of extracted, unconsumed SO4(2-) and extracted S(-II). Results indicated sulfate reduction activity in the vicinity of the test well. Computed first-order rate coefficients for sulfate reduction ranged from 0.043 +/- 0.013 to 0.130 +/- 0.015 day-1. Isotope enrichment factors (epsilon) computed from sulfur isotope fractionation of extracted, unconsumed SO4(2-) ranged from 20.2 +/- 5.5@1000 to 22.8 +/- 3.4@1000. Together with observed fractionation in extracted S(-II), isotope enrichment factors provided strong evidence for microbially mediated sulfate reduction. Thus, push-pull tests combined with stable sulfur isotope analyses proved useful for the in situ quantification of microbial sulfate reduction in a PHC-contaminated aquifer.

Biodegradation, Environmental↗
PubMed2001

Diagnostic yield of bronchoalveolar lavage following renal transplantation.

Organ transplant recipients are at high risk of infectious pulmonary complications. In this retrospective study, the diagnostic yield of bronchoalveolar lavage (BAL) was evaluated in renal transplant recipients. The results were analysed in special regard to the clinical presentation of pulmonary infections and the possible impact of new immunosuppressive agents. Over a 5-year period 91 BAL were performed in 71 renal transplant recipients. Microorganisms were isolated from 69% of BAL (63/91): bacteria 32%; cytomegalovirus (CMV) 27%; Pneumocystis carinii (PC) 22%; other viruses 9% (HSV; EBV, RSV, adenovirus, HHV8); Aspergillus fumigatus 1%. Total cell counts and neutrophil counts in BAL were significantly elevated in bacterial infection, whereas BAL positive for PC showed eosinophilia (P<0.05). There was no association between clinical symptoms and the radiological pattern of infiltrates and the type of infection. Immunosuppression containing tacrolimus or mycophenolate mofetil was associated with a significantly higher percentage of PC and CMV infections compared to cyclosporin-based immunosuppression (65% vs. 30%, P<0.005). A considerable number of PC and CMV infections occurred beyond 6 months after transplantation. In conclusion, BAL has a high diagnostic yield in renal transplant recipients. Infection with CMV and PC should also be considered beyond 6 months after transplantation, and prophylaxis for opportunistic infections should be given if the immunosuppression is intensified.

Adult↗
PubMed2000

P21 gene expression as an indicator for the activity of adenovirus-p53 gene therapy in non-small cell lung cancer patients.

Alterations in the tumor suppressor gene p53 lead to impaired cell cycle control, allowing for the development and growth of tumors. To restore a loss of p53 function, we performed a phase I study of intratumoral gene therapy with adenovirus expressing wild-type p53 in patients with non-small cell lung cancer carrying mutations in the p53 gene. Furthermore, in a phase II study, gene therapy was complemented with simultaneous cisplatin/vinorelbine treatment. Biopsies were obtained from all treated patients before and 24-48 hours after gene therapy to study changes in the expression of p53 target genes. We report here that in most of the cases, the target gene p21 was up-regulated, especially when injection of higher doses of p53-expressing adenovirus was combined with simultaneous chemotherapy, whereas Pig3, previously reported to be highly up-regulated by p53, generally did not show a clear increase. Interestingly, a clear p21 gene response was observed only in tumors showing stabilization or regression. We conclude that p21 appears to be up-regulated after adenovirus-mediated p53 gene transfer and is the most sensitive marker tested for biological response to gene therapy in the small cohort of non-small cell lung cancers that were studied.

Adenoviridae↗
PubMed2000

Takayasu disease with predominant pulmonary involvement.

We report a case of Takayasu's arteritis with predominant pulmonary involvement, which led eventually to complete obliteration of the right pulmonary artery. Subsequently, cavitation and chronic inflammation developed in the nonperfused right lung. A right pneumonectomy was performed to control the infectious process, leading to functional improvement and better control of the underlying immunologic disorder.

Adult↗
PubMed1999

Intrinsic bioremediation of a petroleum hydrocarbon-contaminated aquifer and assessment of mineralization based on stable carbon isotopes.

This study presents a stepwise concept to assess the in situ microbial mineralization of petroleum hydrocarbons (PHC) in aquifers. A new graphical method based on stable carbon isotope ratios (delta 13C) was developed to verify the origin of dissolved inorganic carbon (DIC). The concept and the isotope method were applied to an aquifer in Student, Switzerland, in which more than 34,000 liters of heating oil were accidentally released. Chemical analyses of ground water revealed that in this aquifer locally, anaerobic conditions prevailed, and that PHC mineralization was linked to the consumption of oxidants such as O2, NO3-, and SO4(2-) and the production of reduced species such as Fe2+, Mn2+, H2S and CH4. However, alkalinity and DIC balances showed a quantitative disagreement in the link between oxidant consumption and DIC production, indicating that chemical data alone may not be a reliable assessment tool. delta 13C ratios in DIC have been used before for bioremediation assessment, but results were reported to be negatively influenced by methanogenesis. Using the new graphical method to display delta 13C data, it was possible to identify anomalies found in methanogenic monitoring wells. It could be shown that 88% of the DIC produced in the contaminated aquifer originated from microbial PHC mineralization. Thus, the new graphical method to display delta 13C ratios appears to be a useful tool for the assessment of microbial hydrocarbon mineralization in a complex environment.

Biodegradation, Environmental↗
PubMed1999

Fate of the herbicides mecoprop, dichlorprop, and 2,4-D in aerobic and anaerobic sewage sludge as determined by laboratory batch studies and enantiomer-specific analysis.

Aerobic degradation experiments with the racemic mixtures of mecoprop and dichlorprop revealed that activated sludge collected from the aeration tank of a municipal waste water treatment plant degraded both enantiomers of mecoprop and dichlorprop within 7 days, albeit in an enantioselective manner; the (S) enantiomers were preferentially degraded. Mecoprop, dichlorprop, and 2,4-D were completely metabolized under aerobic conditions, as shown by the 86-98% elimination of dissolved organic carbon. Under anaerobic conditions, the concentration of 2,4-D decreased exponentially with a first-order reaction rate constant of 0.24 per day and without a lag-phase. After an incubation time of 17 days, 2,4-D was completely removed. 2,4-Dichlorophenol was the main metabolite of anaerobic 2,4-D degradation; only traces of 4-chlorophenol were detected. In contrast, the chiral phenoxypropionic acid herbicides mecoprop and dichlorprop persisted under anaerobic conditions during 49 days of incubation.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1999

gamma-L-glutamyl-L-DOPA inhibits Na(+)-phosphate cotransport across renal brush border membranes and increases renal excretion of phosphate.

BACKGROUND: For treatment of phosphate (Pi) overload in various pathophysiological states, an agent that selectively increases renal Pi excretion would be of major value. Previously, we have shown that dopamine (DA) inhibits Na(+)-Pi cotransport in renal epithelia. However, the administration of DA or its immediate precursor L-DOPA increases DA in multiple tissues. Synthetic dipeptide gamma-L-glutamyl-L-DOPA (gludopa) can serve as an inactive precursor (pro-pro-drug) of DA. This study tested the hypothesis that, because of the unique colocalization of gamma-glutamyltransferase (gamma-GT), aromatic amino acid decarboxylase, Na(+)-Pi cotransporter, and Na(+)-L-DOPA cotransporter in brush border membrane (BBM) of proximal tubular cells, gludopa may elicit phosphaturia by action of DA generated within the kidney. METHODS: Thyroparathyrectomized rats were given placebo, or gludopa, or gludopa + gamma-GT inhibitor acivicin. Urinary excretion of Pi, Ca2+, Na+, K+, DA, cAMP, and cGMP was determined, and Na(+)-Pi cotransport was measured in BBM prepared from kidneys of rats at the end of the experiment. RESULTS: The administration of gludopa resulted in: (a) an inhibition of Na(+)-Pi cotransport, but not cotransport of Na(+)-proline and Na(+)-alanine in BBM; (b) an increase (+300%) of fractional excretion (FE) of Pi and a drop (-35%) of plasma Pi, whereas the plasma levels and FEs of Ca2+, Na+, and K+ were unchanged; (c) an increase in urinary excretion of cAMP. but not cGMP; (d) a 1000-fold increase of urinary excretion of DA, without a change in excretion of norepinephrine; and (e) an incubation of gludopa with BBM in vitro, which caused a release of L-DOPA, and the in vivo administration of acivicin, which blocked actions of gludopa to inhibit Na(+)-Pi cotransport and to increase urinary excretions of Pi and DA. CONCLUSIONS: We conclude that colocalization of enzymes of biotransformation, BBM transporters, and the autocrine/paracrine DA system in cells of proximal tubules constitutes a cellular basis for the potent and specific phosphaturic action of gludopa.

Alanine↗
PubMed1997

Cytoprotective effects of adrenomedullin in glomerular cell injury: central role of cAMP signaling pathway.

Activation of cAMP signaling pathway was shown to inhibit some pathobiologic processes in mesangial cells (MC). We investigated whether adrenomedullin (ADM), a potent agonist of adenylate cyclase, is synthesized in MC and whether it can, via cAMP, suppress the generation of reactive oxygen metabolites (ROM) and proliferation of cells in glomeruli. With the use of an immunohistologic technique ADM was detected in mesangial and microvascular areas of rat glomeruli. MC grown in primary culture synthesized ADM, and the synthesis was stimulated by TNF alpha and IL-1 beta but not by PDGF and EGF. ADM inhibited ROM generation in MC dose-dependently and caused in situ activation of protein kinase A (PKA). In macrophages (cell line J774) ROM generation was about four times higher than in MC and was inhibited by ADM in a similar way as in MC. The rate of MC proliferation, measured by [3H]-incorporation, and the activity of mitogen-activated protein kinase (MAPK) stimulated by PDGF and EGF were dose-dependently inhibited by ADM; the maximum inhibition (at 10 nM ADM) was about -80%. Mitogenesis of MC and MAPK activity when stimulated to a similar extent by endothelin (ET-1) was inhibited by ADM to a significantly (P < 0.01) lesser degree (-30%). Further, ADM inhibited PDF-stimulated mitogenesis and activation of MAPK in cultured vascular smooth muscle cells (VSMC). The inhibition of PDGF-activated MAPK by ADM in VSMC was reversed by the protein kinase A (PKA) inhibitor, H89. Taken together, results indicate the adrenomedullin (ADM) generated in mesangial cells (MC) can suppress, via activation of the cAMP-protein kinase A (PKA) signaling pathway, reactive oxygen metabolites (ROM) generation in MC and infiltrating macrophages as well as mitogen-activated protein kinase (MAPK)-mediated mitogenesis in MC and vascular smooth muscle cells (VSMC). We suggest that introglomerular ADM may serve as a cytoprotective autoacoid that suppresses pathobiologic processes evoked by immuno-inflammatory injury of glomeruli.

Adrenomedullin↗
PubMed1997

Evaluation of newer prognostic markers for adult soft tissue sarcomas.

PURPOSE: In addition to tumor size, grade, location, and the presence of metastases, other factors may be useful in prognostication for adults with soft tissue sarcoma (STS). This study examines the relationship of MDR-1 mRNA, p-glycoprotein (P-gp), Ki-67 expression, and DNA content expression to clinical outcome in adults with STS. PATIENTS AND METHODS: Snap-frozen STS specimens from 65 patients were analyzed and compared with clinical outcomes. Immunohistochemistry was performed for the Ki-67 antigen and P-gp. DNA content was determined using the Feulgen reaction and quantitated using image analysis. MDR-1 mRNA expression was determined using a reverse-transcriptase polymerase chain reaction (RT-PCR)-based assay. RESULTS: P-glycoprotein expression was found by immunohistochemistry in 48% of cases with 5-year overall (54% v 14%, P = .07) and disease-free survival rates (32% v 18%, P = .039) higher in high-grade tumors that did not express P-gp. MDR-1 mRNA was detected in 51% of cases and no patient with high levels of MDR-1 mRNA expression was a long-term survivor. Patients with diploid tumors had significantly better survival than those with nondiploid tumors (51% v 31%, P = .03). High levels of Ki-67 were associated with poorer overall survival (46% v 31%, P = .04). On multivariate analysis, American Joint Committee on Cancer (AJCC) staging, DNA content, Ki-67, and P-gp staining were significant prognostic factors for 5-year overall and disease-free survival. CONCLUSION: P-gp expression, high-level Ki-67 expression, and nondiploid DNA content are independent prognostic indicators that correlate with poor outcomes in STS patients. However, MDR-1 mRNA was not found to be predictive of survival. These newer markers are useful additions to AJCC staging for prognostication for patients with STS. Such markers may be useful in selecting high-risk STS patients who could benefit from systemic adjuvant therapy.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

[Lung transplantation].

Human lung transplantation was successfully performed in the early eighties and is now an option for patients with endstage lung disease, which is associated with poor survival. Most frequent indications for lung transplantation are emphysema, cystic fibrosis, fibrosing alveolitis, primary pulmonary hypertension and Eisenmenger's syndrome. Single lung transplantation (SLT) is most often performed in emphysema, fibrosing alveolitis and other diseases which are not associated with chronic infection of the lung. Double lung transplantation was recently replaced by the technique of sequential single lung or bilateral lung transplantation (BLT). Cardiopulmonary bypass can often be avoided and problems of the airway anastomosis are less frequent using BLT. Main indications for this procedure are cystic fibrosis, bronchiectasis and primary pulmonary hypertension (PPH). In PPH often only SLT is performed. Cor pulmonale is reversible following SLT or BLT even if the heart is not replaced. Combined heart-lung transplantation (HLT) is reserved for some cases of Eisenmenger's syndrome and few centers still prefer HLT in patients with cystic fibrosis. Patients are usually accepted for transplantation when they are considered to have life expectancy of 12 to 24 months. Quality of life and physical working capacity are severely decreased and patients suffer dyspnea NYHA grade III or IV. Most of the patients are hypoxic and need continuous oxygen therapy. Hypercapnia is also a negative predictive factor for survival without transplantation. In PPH cardiac index of less than 2 litres/m2 is associated with poor outcome. Not only absolute values for FEV1 and pO2 have to be considered in finding the best moment for assessment for transplantation but the clinical course of the disease during previous months and years also has to be taken into account. Contraindications to transplantation include acute infection, concomitant diseases of other organs, bronchial carcinoma and psychiatric disorders if noncompliance is likely. To achieve good results after lung transplantation, proper donor and recipient selection, experienced surgery and careful postoperative management are essential. Complications must be diagnosed early to provide effective treatment. Most complications occur within the first months after surgery. Early complications include primary organ failure, pleural bleeding, problems at the site of the airway anastomosis, infection and acute rejection. Acute rejection is common but can be treated successfully if diagnosed early.(ABSTRACT TRUNCATED AT 400 WORDS)

Comorbidity↗
PubMed1991

The effect of prostaglandin E1 on acute pulmonary artery hypertension during oleic acid-induced respiratory dysfunction.

This study examined the general effect of intravenous PGE1 on RV Ees and effective PA elastance (EA) during acute pulmonary hypertension associated with oleic acid infusion. In eight pigs, RV end-systolic elastance was quantified with the Ees and Ea was defined with reference to the Windkessel model. Oleic acid infusion increased mean PAP and Ea. Prostaglandin E1 reduced PAP and decreased Ea. Ees did not change throughout the study. Mean arterial pressure was reduced and the pulmonary shunt was increased after PGE1 infusion. The PaO2 was reduced. Data from this study suggest that although PGE1 is effective in reducing PAP, it is not as effective in reducing RV afterload. Furthermore, PGE1 does have significant side effects such as reduction of systemic arterial pressure and an increase in pulmonary shunt.

Acute Disease↗
PubMed1989

Effect of N2O on segmental left ventricular function and effective arterial elastance in pigs when added to a halothane-fentanyl-pancuronium anesthetic technique.

The interaction of various concentrations of N2O and a stable halothane-fentanyl-pancuronium anesthetic technique was examined in nine pigs. Segmental myocardial contractility was measured with the end-systolic pressure-length relationship (Ees), and the effective arterial elastance (Ea) was quantified based on the Windkessel model. The addition of 30, 50, and 70% N2O did not change myocardial contractility or the effective arterial elastance. During the 30 and 70% N2O challenge, however, arterial capacitance decreased significantly from a mean (+/- SEM) 0.86 +/- 0.15 to 0.71 +/- 0.0.11 mL/mm Hg with 30% N2O (P less than 0.05) and from 0.90 +/- 0.09 to 0.71 +/- 0.07 mL/mm Hg (P less than 0.05) with 70% N2O. A dose-response relationship for the effect on the arterial capacitance could not be demonstrated. We concluded that in the presence of halothane, fentanyl, and pancuronium, N2O does not depress the normal myocardium or change left ventricular afterload. The decrease in arterial capacitance that occurred when 30 and 70% N2O were given was not sufficient to change the effective afterload and appears to be of no importance to normal left ventricular function.

Animals↗
PubMed1989

Effect of various propofol plasma concentrations on regional myocardial contractility and left ventricular afterload.

The cardiovascular effects of propofol infusions, designed to maintain constant plasma concentrations, were examined in an open-chested pig model. Regional myocardial contractility was measured with the end-systolic pressure-length relationship (Ees) and left ventricular afterload quantified by the effective arterial elastance (Ea). The propofol plasma concentrations in this study varied between 0 and 7.73 (SEM 0.96) micrograms/mL. A significant correlation for the increasing propofol plasma concentration and a decrease in myocardial contractility (P = 0.0056) was demonstrated, and the Ea remained constant. This gave rise to a reduction in stroke volume (P = 0.002) and, combined with a decrease in the heart rate (P = 0.0001), led to a reduction in the cardiac output (P = 0.0001). When the propofol infusion was stopped, myocardial contractility did not recover in parallel with the decrease in plasma propofol concentration.

Anesthetics↗