Successful trimethoprim-sulfamethoxazole therapy in a patient with hyperimmunoglobulin E syndrome

A male patient with hyperimmunoglobulin E syndrome is described. Recurrent lymphadenitis and cutaneous staphylococcal abscesses were resistant to various antibiotics, and chemotaxis and hydrogen peroxide production of polymorphonuclear leukocytes were impaired. Following trimethoprim-sulfamethoxazole therapy, he was free from the above infections, and impaired polymorphonuclear leukocyte functions recovered and serum IgE decreased to approximately one-fifth of its initial level. Subsequent irregular medications, however, resulted in impairment of polymorphonuclear leukocyte functions and an increased serum IgE concentration, which recovered after regular resumption of trimethoprim-sulfamethoxazole treatment. From these results, the beneficial effects of trimethoprim-sulfomethoxazole in hyperimmunoglobulin E syndromgak clinically apparent, but in vitro studies failed to demonstrate the positive effect of trkethoprim-sulfamethoxazole on polymorphonuclear leukocytes and their mechanism still remains to be elucidated.     

Exposure to hydrogen peroxide at TLV level does not induce lung function changes: a longitudinal study

This study reports on longitudinal changes in lung function using spirometry of employees at a beverage processing plant, where exposure information (1995-2001) suggests that the threshold limit value (TLV)-Time Weighted Average (TWA) of 1 ppm was not likely exceeded. Changes over time in lung function (Forced Expiratory Volume of 1st second, FEV1; Forced Vital Capacity, FVC; and FEV1/FVC ratio; all expressed as percent of the predicted) were evaluated by using sparse lung function data obtained from 1993 to 2002 in 43 exposed and 31 unexposed workers. The longitudinal changes were assessed using multiple regression analysis where the dependent variable was the annual change of lung function indices and the independent variables were exposure and smoking habits. With regard to exposure, FVC increased, FEV1 was unchanged, and the FEV1/FVC ratio tended to decrease. The latter difference was not significant when FVC was used as a covariate. The FEV1 is significantly worse in smokers than in non-smokers. These data suggest that no lung function changes occur when the H2O2 levels were compliant to the exposure standard. Our findings support the current TLV-TWA of 1 ppm for H2O2.     

Development of an <Emphasis Type="Italic">in vitro</Emphasis> model of excess intracellular reactive oxygen species

These investigations characterize an in vitro model for generating excess intracellular reactive oxygen species (ROS). This novel model may be useful in the identification and delineation of cellular mechanisms associated with aging due to the link between age and excess oxidative events. The human cell line, MCF7, was stably transfected using the pSV3.neo plasmid housing a gene encoding the Aequorea victoria green fluorescent protein (GFP). Transfected cells were analyzed for maintenance of GFP over time, showing stability of the GFP gene. These studies demonstrate that the presence of fluorescing GFP significantly increases intracellular ROS, creating oxidative stress in these cells. Antioxidant supplementation was evaluated to determine the effectiveness of intracellular H₂O₂ reduction. The results demonstrate that supplementation with a potent antioxidant, such as reduced glutathione, protects cells from oxidative damage by decreasing intracellular concentrations of H₂O₂. This model for intracellular generation of excess ROS establishes a clear method by which the utility of antioxidant supplementation to protect against intracellularly generated reactive oxygen species may be evaluated.     

The Use of an Hydrogen Peroxide Multipurpose Isolator for Inhouse Preparation of Human Embryo Culture Media: A Unique Successful Swiss Randomized Prospective Study

Purpose: To develop inhouse made (IHM) embryo culture medium with a Multipurpose Isolator and compare the embryo development in a prospective randomized study with commercial media.Methods: Fertilization by intracytoplasmic single sperm injection (ICSI) of Metaphase II oocytes obtained after 96 controlled ovarian hyperstimulation cycles in patients not older than 37 years. Transfer of zygotes to IHM or commercial Cook Sydney IVF Cleavage medium (SIC) immediately after pronucleus observation. Evaluation of embryo cleavage and score, pregnancy, and implantation rate.Results: From 100 zygotes cultured in SIC, 61% were at the 4 cell stage 45 h after ICSI compared to 77% (78/101) in the IHM, P<0.05. The mean embryo score with IHM was 3.9±0.9 compared to 3.5±1.2 with SIC, P<0.05. The clinical pregnancy rate per transfer was 38.9% (37/95), the implantation rate was 23% (46/200), and no differences were observed between the groups.     

Imbalance of antioxidant enzymes in tumor cells and inhibition of proliferation and malignant features by scavenging hydrogen peroxide

The aim of this study was to evaluate the endogenous alterations of the antioxidant enzymes in tumor cells and to specifically compensate the resulting changes in the levels of reactive oxygen species (ROS) to control the malignant growth. We determined and compared the activities of antioxidant enzymes and the levels of superoxide anion (O2*-) and hydrogen peroxide (H2O2) in tumor cell lines with different degrees of malignancy, paired with regard to their origin (PB/CH72T4, PDV/PDVC57, and HBL-100/MCF-7). An increase in superoxide dismutase activity and a decrease in the activities of H2O2-detoxifying enzymes, as a function of malignancy, coupled with a rise in H2O2 and a decrease in O2*- were demonstrated. Treatment of cells with exogenous catalase showed a dose-dependent inhibition of proliferation. This inhibition was also demonstrated in several cell lines of different tissue origin and species, suggesting a general role of H2O2 in cell proliferation. Moreover, stable expression of human catalase in MCF-7 cells inhibited proliferation and also reverted malignant features. We conclude that H2O2 played a crucial and general role in the regulation of proliferation and that an endogenous imbalance in antioxidant enzymes could be a relevant event in the carcinogenesis process.     

Characteristics of tertiary butyl hydroperoxide and hydrogen peroxide conditioned cells withdrawn from peroxide stress

This laboratory has recently reported the preparation of immortal lens epithelial cell lines conditioned to survive in concentrations of peroxide sufficient to cause cataract with in vitro lens culture conditions. The cell conditioning process takes many months during which time the peroxide concentration is gradually increased. It was found that while the acquired resistance to H2O2 was permanent, if tertiary butyl hydroperoxide (TBOOH) was used the resistance was lost within 6-8 weeks of the withdrawal of the peroxide. We now report that resistance is lost within a few days but can be regained within 48 hr. Furthermore, cells resistant to H2O2 while vulnerable to TBOOH could also be rapidly conditioned to tolerate TBOOH in a manner similar to the reconditioning of cells that had lost their TBOOH resistance. The results suggest that a history of exposure to certain oxidative stresses produces a change in cell biology which allows the cell to rapidly respond to the same or other stresses and survive.     

Effects of hypochlorite and hydrogen peroxide on cardiac autonomic receptors and vascular endothelial function

1. Reactive oxygen species (ROS) are known to be involved in the progression of various cardiovascular diseases. One source of ROS is activated neutrophils, which can release superoxide anion radicals and hydrogen peroxide by membrane-bound NAD(P)H oxidases. These ROS not only destroy bacteria, but may also affect mammalian tissue. In addition, hydrogen peroxide serves as a substrate for myeloperoxidase, an enzyme that is released by activated neutrophils during inflammatory processes, as seen, for instance, in reperfusion injury and atherosclerosis. Myeloperoxidase catalyses the oxidation of chloride by hydrogen peroxide, yielding hypochlorite, an extremely potent oxidant. 2. The purpose of the present study was to evaluate the effects of hypochlorite on a variety of receptor-dependent processes in rat isolated left atria and rat thoracic aorta and to compare these results with the phenomena observed after incubation with hydrogen peroxide. 3. In the presence of hypochlorite (300 micro mol/L), the positive inotropic response of alpha1-adrenoceptor stimulation by methoxamine (300 micro mol/L) was converted into a negative inotropic response. In contrast, the positive inotropic effects of the beta1/beta2-adrenoceptor agonist isoprenaline (3 micro mol/L) and endothelin (ET)-1 (100 nmol/L) remained largely unaffected. 4. The inversion of alpha1-adrenoceptor-mediated inotropy was not obtained in the presence of hydrogen peroxide (500 micro mol/L). Hydrogen peroxide did not affect the positive inotropic response of isoprenaline, but it completely abolished the inotropic effect of ET-1. 5. The effect of cardiac M2-receptor stimulation was studied in the presence of hypochlorite and hydrogen peroxide. The negative inotropic response to acetylcholine (ACh) was significantly enhanced after hypochlorite incubation compared with control. 6. In the rat thoracic aorta, endothelial function, evaluated by means of ACh-induced vasodilation, was completely abolished in the presence of hypochlorite (100 micro mol/L), but remained unaffected by treatment with the same concentration of hydrogen peroxide. 7. From these data, we conclude that hypochlorite exerts more toxic properties than its precursor hydrogen peroxide, leading to substantial physiological alterations in cardiac and vascular tissue.     

Mechanism of captopril toxicity to a human mammary ductal carcinoma cell line in the presence of copper

Captopril (D3mercapto2methylpropanoylLproli ne) is an angiotensin converting enzyme (ACE) inhibitor, used widely in the treatment of hypertension and congestive heart failure. Captopril also inhibits proliferation of a variety of cell types, including several lacking ACE and renin acitvity. We have previously demonstrated that human mammary ductal carcinoma cells are among the cell types whose mitotic activity is inhibited by captopril. In those cells, captopril also reduces estrogen receptor (ER) and increases progesterone receptor (PR) concentrations. The present study evaluated the mechanism of captopril's antiproliferative action in an ER/PRnegative human mammary ductal carcinoma cell line, Hs578T. Cells grown in a 10% serum medium showed negligible changes in the presence of captopril alone. However, in the presence of subphysiologic concentrations of copper salts or copperloaded ceruloplasmin, captopril caused a dosedependent reduction in cell number, thymidine incorporation and mitochondrial dehydrogenase activity. In contrast, iron salts and ironsaturated transferrin had no effect on captopril activity. Catalase and horseradish peroxidase nullified the cytotoxic effects of captopril/Cu⁺⁺, whereas H₂O₂ mimicked those effects. These data are consistent with the notion of a coppercatalyzed oxidation of captopril, leading to the generation of H₂O₂ as the cytotoxin to this clinically important cell type.     

Hydrogen peroxide mediates damage by xanthine and xanthine oxidase in cerebellar granule neuronal cultures

The free radical-generating system of xanthine and xanthine oxidase is commonly used experimentally as a source of superoxide anion, which can produce oxidative stress, leading to cellular damage and death. Models of oxidative stress are important in elucidating pathologies associated with increased levels of reactive oxygen species, including stroke and neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. We therefore, examined the effect of the xanthine/xanthine oxidase system on the viability of postnatal cerebellar granule neurones obtained from 8-day old Sprague–Dawley rat pups. Xanthine (100 μM) and xanthine oxidase (0.02 U/ml) applied for 1 or 6 h reduced the viability of cells at 8 div assessed using the alamar blue assay, and induced morphological changes, such as shrinkage of the cell bodies and neurites. Heat-inactivation of xanthine oxidase resulted in complete loss of its activity. Superoxide dismutase (250 U/ml) failed to modify the damage by xanthine and xanthine oxidase, while catalase (250 U/ml) completely prevented it. When applied alone, xanthine oxidase significantly lowered cell viability, an effect that was blocked by allopurinol and catalase, but not by superoxide dismutase. The results indicate that xanthine and xanthine oxidase can produce predominantly hydrogen peroxide instead of the superoxide anion. Cerebellar granule cells in culture may also possess significant levels of endogenous xanthine.