MitoVitE, a mitochondria-targeted antioxidant, limits paclitaxel-induced oxidative stress and mitochondrial damage in vitro, and paclitaxel-induced mechanical hypersensitivity in a rat pain model.

BACKGROUND: Neuropathic pain is a common side-effect of chemotherapy. Although precise mechanisms are unclear, oxidative stress and mitochondrial damage are involved. We investigated whether the mitochondria targeted antioxidant, MitoVitE, provided better protection against paclitaxel-induced mitochondrial damage in rat dorsal root ganglion (DRG) cells, than a non-targeted form of vitamin E, Trolox. We also determined whether MitoVitE, compared with duloxetine, could limit paclitaxel-induced mechanical hypersensitivity in rats. METHODS: Mitochondrial function was measured in DRG cells exposed to paclitaxel with and without MitoVitE or Trolox. The effect of MitoVitE or Trolox on paclitaxel-induced cell killing in cancer cell lines was also determined. Rats received a cumulative dose of 8 mg kg-1 paclitaxel plus either MitoVitE (2 mg-1 kg day-1), duloxetine (10 mg kg-1 day-1) or vehicle control daily. Mechanical hind paw withdrawal thresholds were measured every two days. RESULTS: Paclitaxel caused loss of membrane potential in DRG cells. At 100 µM paclitaxel median [range] change was 61[44-78]%, P < 0.0001, which was ameliorated by MitoVitE (86[62-104]%) but not Trolox (46[46-57]%). Similarly, loss of metabolic activity and glutathione induced by paclitaxel (both P < 0.0001) were reduced by MitoVitE but not Trolox. Cytotoxicity of paclitaxel was not affected by co-exposure of ovarian cancer cells to either MitoVitE or Trolox, but was slightly reduced against breast cancer cells, in the presence of Trolox. Mean (SD) areas under the curve of withdrawal thresholds at 6 h after injection in rats given paclitaxel + control, or + MitoVitE (P < 0.0001) or + duloxetine (P < 0.0001) were 110 (5), 145 (10) and 156 (13) respectively. CONCLUSIONS: Paclitaxel affected mitochondrial function and glutathione in DRG cells, which was abrogated by MitoVitE but not Trolox, without decreasing cancer cell cytotoxicity. In rats, paclitaxel-induced mechanical hypersensitivity was ameliorated by MitoVitE treatment to an extent similar to duloxetine. These data confirm mitochondria as a mechanistic target for paclitaxel-induced damage and suggest mitochondria targeted antioxidants as future therapeutic strategies.

Pharmacological activation of endogenous protective pathways against oxidative stress under conditions of sepsis.

BACKGROUND: Mitochondrial oxidative stress has a role in sepsis-induced organ dysfunction. The endogenous mechanisms to initiate protective pathways are controlled by peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC1α) and nuclear factor erythroid 2-like 2 (NFE2L2). Activation of these pathways are potential therapeutic targets in sepsis. We used pharmacological activators to determine the effects on markers of mitochondrial damage and inflammation in human endothelial cells under conditions of sepsis. METHODS: Human endothelial cells were exposed to lipopolysaccharide plus peptidoglycan G to mimic a sepsis environment, with a range of concentrations of a selective synthetic agonist of silent information regulator-1 (SIRT-1) which activates PGC1α, or bis(2-hydroxy-benzylidene) acetone (2HBA) which activates NFE2L2, with and without inhibitors of these pathways. Cells were cultured for up to seven days and we measured mitochondrial membrane potential, metabolic activity, and density (as a marker of biogenesis), interkeukin-6 (to reflect inflammation) and glutathione (as a measure of antioxidant status). RESULTS: Under conditions mimicking sepsis, activation of the PGC1α and NFE2L2 pathways protected cells from LPS/PepG-induced loss of mitochondrial membrane potential (P=0.0002 and P=0.0009, respectively) and metabolic activity (P=0.05 and P<0.0001, respectively), and dampened interleukin-6 responses (P=0.003 and P=0.0001, respectively). Mitochondrial biogenesis (both P=0.0001) and glutathione (both P<0.0001) were also increased. These effects were blunted by the respective inhibitors. CONCLUSIONS: The development of organ dysfunction during human sepsis is linked to mitochondrial dysfunction, and so activation of PGC1α/NFE2L2 is likely to be beneficial. These pathways are attractive therapeutic targets for sepsis.

Low zinc and selenium concentrations in sepsis are associated with oxidative damage and inflammation.

BACKGROUND: Oxidative stress with dysregulated inflammation are hallmarks of sepsis. Zinc and selenium have important antioxidant functions, such that they could be important in patients with sepsis. We used an in vitro approach to assess the effect of zinc and selenium on oxidative stress, mitochondrial function, and inflammatory responses in conditions mimicking sepsis and related the findings to plasma concentrations and biomarkers in patients with and without sepsis. METHODS: Human endothelial cells were exposed to a range of zinc and selenium concentrations in conditions mimicking sepsis. Zinc, selenium, and a series of biomarkers of oxidative stress and inflammation were measured in plasma from critically ill patients with and without sepsis. RESULTS: Culturing cells with different concentrations of zinc caused altered zinc transporter protein expression and cellular zinc content, and selenium affected glutathione peroxidase 3 activity. Although zinc or selenium at physiological concentrations had no effect on interleukin-6 release in vitro, higher concentrations of the trace elements were associated with improved mitochondrial function. Plasma zinc and selenium concentrations were low in patients [zinc: median (range) 4.6 (2.1-6.5) µM in control patients without sepsis and 3.1 (1.5-5.4) µM in patients with sepsis, P=0.002; and selenium: 0.78 (0.19-1.32) µM in control patients and 0.42 (0.22-0.91) µM in sepsis patients, P=0.0009]. Plasma concentrations of interleukin-6, other biomarkers of inflammation, and markers of oxidative damage to proteins and lipids were elevated, particularly in patients with sepsis, and were inversely related to plasma zinc and selenium concentrations. CONCLUSIONS: Zinc and selenium concentrations were reduced in critically ill patients, with increased oxidative stress and inflammatory biomarkers, particularly in patients with sepsis. Oxidative stress as a result of suboptimal selenium and zinc concentrations might contribute to damage of key proteins. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: registration number NCT01328509.

Antioxidants that protect mitochondria reduce interleukin-6 and oxidative stress, improve mitochondrial function, and reduce biochemical markers of organ dysfunction in a rat model of acute sepsis.

BACKGROUND: Sepsis-induced organ failure is the major cause of death in critical care units, and is characterized by a massive dysregulated inflammatory response and oxidative stress. We investigated the effects of treatment with antioxidants that protect mitochondria (MitoQ, MitoE, or melatonin) in a rat model of lipopolysaccharide (LPS) plus peptidoglycan (PepG)-induced acute sepsis, characterized by inflammation, mitochondrial dysfunction and early organ damage. METHODS: Anaesthetized and ventilated rats received an i.v. bolus of LPS and PepG followed by an i.v. infusion of MitoQ, MitoE, melatonin, or saline for 5 h. Organs and blood were then removed for determination of mitochondrial and organ function, oxidative stress, and key cytokines. RESULTS: MitoQ, MitoE, or melatonin had broadly similar protective effects with improved mitochondrial respiration (P<0.002), reduced oxidative stress (P<0.02), and decreased interleukin-6 levels (P=0.0001). Compared with control rats, antioxidant-treated rats had lower levels of biochemical markers of organ dysfunction, including plasma alanine amino-transferase activity (P=0.02) and creatinine concentrations (P<0.0001). CONCLUSIONS: Antioxidants that act preferentially in mitochondria reduce mitochondrial damage and organ dysfunction and decrease inflammatory responses in a rat model of acute sepsis.

Does manual anaesthetic record capture remove clinically important data?

BACKGROUND: Numerous studies have shown smoothing and inaccuracies in handwritten anaesthetic records, but the clinical relevance of these findings is unclear. We therefore sought to determine whether the behaviour of anaesthetists differed in assessing anaesthetic records re-synthesized from either handwritten or automated records. METHODS: In a recent New Zealand study (ACTRN12608000068369), both manual and automated records were acquired from the same anaesthetics. Manual records were digitized using digital callipers. Selected data (systolic, diastolic, and mean arterial pressure; heart rate; Sp(O(2)); E'(CO(2))) were replayed in a computerized anaesthetic record-keeping system with which the participants were familiar, to present manual and corresponding automated anaesthetic records. Ten anaesthetists, randomly selected from participants in this study, assessed 24 replayed records (a manual and an automated record from each of 10 anaesthetics, with two of each displayed twice). They indicated where and how they would have intervened if administering these anaesthetics. We compared the number of interventions for each pair of anaesthetics and subjective measures of anaesthetic quality. RESULTS: In our selected sample of unstable anaesthetics, the mean (SD) number of interventions per anaesthetic was 4.0 (2.9) vs 5.2 (3.4) for manual and automated records, respectively (P=0.013). Subjective measures did not differ significantly between record types. Assessors identified 32 artifacts in six manual records (0.32/record assessment) and 105 artifacts in eight automated records (1.05/record assessment), P=0.14. Replicability was moderate (COV 39.8%). CONCLUSIONS: In comparison with computerized record-keeping, manual record-keeping resulted in loss of clinically relevant information.

Melatonin and structurally similar compounds have differing effects on inflammation and mitochondrial function in endothelial cells under conditions mimicking sepsis.

BACKGROUND: Development of organ dysfunction associated with sepsis is due in part to oxidative damage to mitochondria. Melatonin regulates the sleep-wake cycle and also has potent antioxidant activity. The aim of this study was to determine the effects of melatonin and other structurally related compounds on mitochondrial function, endogenous glutathione (GSH), and control of cytokine expression under conditions mimicking sepsis. METHODS: Human endothelial cells were treated with lipopolysaccharide (LPS) plus peptidoglycan G (PepG) to simulate sepsis, in the presence of melatonin, 6-hydroxymelatonin, tryptamine, or indole-3-carboxylic acid. Nuclear factor κB (NFκB) activation, interleukin (IL)-6 and IL-8, total glutathione, mitochondrial membrane potential, and metabolic activity were measured. RESULTS: LPS and PepG treatment resulted in elevated IL-6 and IL-8 levels preceded by activation of NFκB (all P<0.0001). Treatment with all four compounds resulted in lower IL-6 and IL-8 levels, and lower NFκB activation (P<0.0001). Loss of mitochondrial membrane potential and endogenous glutathione was seen when cells were exposed to LPS/PepG, but these were maintained in cells co-treated with melatonin, tryptamine, or 6-hydroxymelatonin (P<0.05), but not indole-3-carboxylic acid. Metabolic activity decreased after exposure to LPS/PepG and was maintained by melatonin and 6-hydroxymelatonin at the highest concentrations only. CONCLUSIONS: We have shown that in addition to melatonin, other structurally related indoleamine compounds have effects on NFκB activation and cytokine expression, GSH, mitochondrial membrane potential, and metabolic activity in endothelial cells cultured under conditions mimicking sepsis. Further work is needed to determine whether these compounds represent therapeutic approaches for disrupting the oxidative stress-inflammatory response signalling pathway in sepsis.

Regulation of pentraxin-3 by antioxidants.

BACKGROUND: Pentraxin-3 (PTX3) may be a useful biomarker in sepsis, but its regulatory mechanisms are still unclear. Oxidative stress is well defined in patients with sepsis and has a role in regulation of inflammatory pathways which may include PTX3. We undertook an in vitro study of the effect of antioxidants on regulation of PTX3 in endothelial cells combined with a prospective observational pilot study of PTX3 in relation to markers of antioxidant capacity and oxidative stress in patients with sepsis. METHODS: Human endothelial cells were cultured with lipopolysaccharide 2 microg ml(-1), peptidoglycan G 20 microg ml(-1), tumour necrosis factor (TNF) alpha 10 ng ml(-1), interleukin-1 (IL-1) beta 20 ng ml(-1), or killed Candida albicans yeast cells plus either N-acetylcysteine (NAC) 25 mM, trolox 100 mM, or idebenone 1 microM. Plasma samples were obtained from 15 patients with sepsis and 11 healthy volunteers. RESULTS: PTX3 levels in plasma were higher in patients with sepsis than in healthy people [26 (1-202) ng ml(-1) compared with 6 (1-12) ng ml(-1), P=0.01]. Antioxidant capacity was lower in patients with sepsis than healthy controls [0.99 (0.1-1.7) mM compared with 2.2 (1.3-3.3) mM, P=0.01]. In patients with sepsis, lipid hydroperoxide levels were 3.32 (0.3-10.6) nM and undetectable in controls. We found no relationship between PTX3 and antioxidant capacity or lipid hydroperoxides. Cell expression of PTX3 increased with all inflammatory stimulants but was highest in cells treated with TNFalpha plus IL-1beta. PTX3 concentrations were lower in cells co-treated with antioxidants (all P<0.05), associated with lower nuclear factor kappaB expression for NAC and trolox (P<0.05). CONCLUSIONS: PTX3 expression is down-regulated in vitro by antioxidants. Plasma levels of PTX3 are elevated in sepsis but seem to be unrelated to markers of oxidant stress or antioxidant capacity.

Activated protein C inhibits chemotaxis and interleukin-6 release by human neutrophils without affecting other neutrophil functions.

BACKGROUND: Activated protein C (APC) therapy reduces mortality in high-risk patients with severe sepsis. The effects of APC on inflammatory responses have also been reported. Neutrophils are key cells involved in early host defence mechanisms in sepsis. We hypothesized that APC may have effects on neutrophil function. METHODS: Neutrophils were isolated from 10 healthy volunteers and incubated in the presence of lipopolysaccharide (LPS) with and without a range of therapeutically relevant concentrations of recombinant human APC. Respiratory burst activity was determined using flow-activated cell sorting (FACS) analysis. Apoptosis was determined using Annexin-V staining and FACS analysis. Cytokine bead array was used to simultaneously measure three key cytokines in culture supernatants: interleukin (IL)-1 beta, -6, and -8. For chemotaxis, neutrophil migration through a 5 microm membrane was measured in response to formyl-methyl-leucine-phenylalanine (FMLP) or IL-8 in the presence and absence of APC. RESULTS: Exposure to LPS resulted in significant increases in respiratory burst activity, IL-1 beta, -6, and -8 expression (all P<0.0001) and decreased the number of apoptotic cells (P<0.0001). The APC exposure resulted in a significant release of IL-6 (P=0.04) without affecting other cytokines. Respiratory burst and apoptosis were also unaffected by APC. Neutrophil chemotaxis in response to either FMLP or IL-8 was reduced by APC (P=0.005 and 0.007, respectively). CONCLUSIONS: This pilot study showed that APC treatment of human neutrophils results in a decreased IL-6 expression and chemotaxis, without affecting other cytokines, apoptosis, or respiratory burst activity.

Effects of disrupting medial prefrontal cortex GABA transmission on decision-making in a rodent gambling task.

RATIONALE: Decision-making is a complex cognitive process that is mediated, in part, by subregions of the medial prefrontal cortex (PFC). Decision-making is impaired in a number of psychiatric conditions including schizophrenia. Notably, people with schizophrenia exhibit reductions in GABA function in the same PFC areas that are implicated in decision-making. For example, expression of the GABA-synthesizing enzyme GAD67 is reduced in the dorsolateral PFC of people with schizophrenia. OBJECTIVES: The goal of this experiment was to determine whether disrupting cortical GABA transmission impairs decision-making using a rodent gambling task (rGT). METHODS: Rats were trained on the rGT until they reached stable performance and then were implanted with guide cannulae aimed at the medial PFC. Following recovery, the effects of intra-PFC infusions of the GABAA receptor antagonist bicuculline methiodide (BMI) or the GABA synthesis inhibitor L-allylglycine (LAG) on performance on the rGT were assessed. RESULTS: Intracortical infusions of BMI (25 ng/µl/side), but not LAG (10 µg/µl/side), altered decision-making. Following BMI infusions, rats made fewer advantageous choices. Follow-up experiments suggested that the change in decision-making was due to a change in the sensitivity to the punishments, rather than a change in the sensitivity to reward magnitudes, associated with each outcome. LAG infusions increased premature responding, a measure of response inhibition, but did not affect decision-making. CONCLUSIONS: Blocking GABAA receptors, but not inhibiting cortical GABA synthesis, within the medial PFC affects decision-making in the rGT. These data provide proof-of-concept evidence that disruptions in GABA transmission can contribute to the decision-making deficits in schizophrenia.

Surgical alternatives in the treatment of life-threatening ventricular arrhythmias.

We present our experience in the treatment of life-threatening ventricular tachycardia using electrophysiologically guided surgery (97 patients), automatic implantable cardioverter defibrillator (AICD) (42 patients), and orthotopic heart transplantation (15 patients). Eighty-three percent of these patients had ischemic and 17%, nonischemic heart disease. Our results of electrophysiologically directed surgery show an early mortality of 10% and a recurrence of 5% in the ischemic group. In the nonischemic group, the recurrence was 45%. The AICD was implanted in 31 patients with ischemic heart disease, in 5 with ventricular dysplasia, and in 6 with dilative cardiomyopathy, the ejection fractions ranging from 12% to 65%, with a mean of 30%. Early and late mortalities were 5% and 19%, respectively. The AICD was effective in all patients. Survival rate at 1 year was 83% +/- 6.4%. Thirteen of 15 patients have survived heart transplantation for 3-20 months (mean: 11 months). Ejection fractions prior to transplantation ranged from less than 10% to 34% (mean: 16%). We conclude that electrophysiologically guided surgery is highly effective in most cases of ischemia-related ventricular tachycardia. The AICD is considered a palliative alternative in patients with either poor ventricular function, no electrophysiological substrate, or multimorphological tachycardia. Heart transplantation has to be considered especially in young patients in whom progression of the underlying disease can be anticipated. Bridging by AICD is possible when transplantation is not immediately available or recommendable.

[Variants of surgical treatment of ventricular tachycardia]. / Varianty khirurgicheskogo lecheniia zheludochkovykh takhikardii.

The paper presents the practice of the Hannover++ Surgery Center (FRG) in managing ventricular tachycardias: 122 patients underwent a radical operation by using electrophysiological studies, 92 patients were implanted an automatic cardioverter/defibrillator, 12 had homotopic cardiac transplantation. Coronary heart disease was present in 82%, non-ischemic heart disease was seen in 18%. The outcomes of operations with electrophysiological studies were as follows: deaths were 9% in early periods, relapses occurred in 5% of patients with coronary heart disease and in 46% of non-coronarogenic diseases. The cardioverter/defibrillator was implanted in 71 patients with coronary heart disease and 21 patients with non-coronarogenic diseases. The mean ejection fraction was 32%. The early and late mortality rates were 5 and 19%%, respectively. Out of 19 patients who had undergone transplantation, 17 were alive in follow-ups of 3 to 36 months. The ejection fraction before transplantation averaged 17%. The surgery for ventricular tachycardias with electrophysiological support is a highly effective method of therapy. The implantation of a cardioverter/defibrillator is regarded as a palliative intervention in patients with ventricular malfunction in the absence of an electrophysiological tachycardia substrate or in the presence of polymorphic tachycardia. Cardiac transplantation should be performed chiefly in young patients with evolving major disease. The transplantation may be replaced by implantation of a cardioverter if the former is impracticable or will be performed in future.

HOMA-S is associated with greater HbA1c reduction with a GLP-1 analogue in patients with type 2 diabetes.

Exenatide, a glucagon-like peptide-1 (GLP-1) analogue, is an effective glucoregulator for treating overweight individuals, not at target HbA1 c. This prospective study aimed to determine whether estimates of beta cell function (HOMA-B) and insulin sensitivity (HOMA-S) predict response to Exenatide treatment.Prospective data on 43 type 2 diabetes patients were collected for up to 2.8 years in UK primary care. HOMA-B and HOMA-S were estimated prior to initiating Exenatide, with monitoring of cardio-metabolic risk factors.Mean (SD) age and BMI pre-treatment were 54.1±10.5 years and 35.7±7.5 kg/m2 respectively. HbA1c decreased (mean reduction 0.9%, p=0.04; p for trend=0.01) in 61% of patients. In univariate analyses, HOMA-S as a measure of insulin sensitivity was inversely (ß=- 0.41, p 0.009) related to change in HbA1c, with no relation for HOMA-B.In a random effects regression model that included age at baseline, weight, LDL-C, HDL-C and triglycerides, change in HbA1c (ß= - 0.14, p<0.001) and HDL-C (ß= - 0.52, p=0.011) were independently associated with increasing insulin sensitivity (r2=0.52). Thus patients with greater measured insulin sensitivity achieved greater reduction in HbA1c independent of the factors described above.In logistic regression those in the highest tertile of log-HOMA-S were 45% more likely to have a fall in HbA1c with an odds ratio (OR) of 0.55 (95% CI 0.47-0.66) p<0.0001 (log likelihood ratio for the model χ2=71.6, p<0.0001).Patients with greater measured insulin sensitivity achieve greater reduction in HbA1c with Exenatide. Determination of insulin sensitivity may assist in guiding outcome expectation in overweight patients treated with GLP-1 analogues.

Bilobed chest flap.

The bilobed chest flap is presented as an additional method of reconstruction in head and neck surgery. The flap is a combination of two previously described flaps: the deltopectoral flap and the anterior-superior-oblique chest flap. It is based on four perforating vessels supporting an area of 480 to 560 sq cm. The superior and inferior lobes can be used simultaneously for external cervical coverage or in combination for external coverage and internal lining. The importance of this flap is appreciated in the patient who needs two deltopectoral flaps but who has had previous chest surgery on one side, or in one who requires two deltopectoral flaps with a planned fistula which then requires a third flap for closure.

Surgical treatment of the Wolff-Parkinson-White syndrome--experiences in 120 patients.

Since January 1984, 120 patients (78 male, 42 female; aged 3 to 66 years) with the Wolff-Parkinson-White (WPW) syndrome have been operated upon. The indication for surgery was documented recurrent, paroxysmal tachycardia refractory to medical treatment in 118 cases. Twenty-two patients (18%) had additional heart disease. One hundred and twenty patients had a total of 140 accessory pathways (AP). AP were localized at the left free wall in 63% (87 AP), at the right free wall in 24% (35 AP), and septally in 13% (18 AP). Sixteen patients (13%) had multiple AP (12 patients had two and four patients had three AP), 124 AP were known pre-operatively (88%), 133 were localized intra-operatively (94%) and seven were diagnosed during re-operation (6%). Surgery in 28 patients with left lateral AP was via the epicardial approach and the endocardial approach in 59. Of 15 patients with right lateral AP, the surgical approach was epicardial in two and transmural in 13. A cryosurgery was also used in 117 patients. Fifteen patients suffered recurrences, in 12 of whom repeat surgery was required. One hundred and thirty-six AP (97%) were dissected successfully, of which 14 (10%) were ablated during re-operation. All patients survived the initial operation, but two patients died after re-operation. One patient is pacer-dependent due to persisting postoperative atrioventricular (AV) block. We conclude that surgical dissection of accessory pathways can be offered as an alternative to non-surgical treatment modes, at a low risk and with a high success rate.

[Surgical therapy of life-threatening tachycardic cardiac arrhythmias in children]. / Chirurgische Therapie lebensbedrohlicher tachykarder Herzrhythmusstörungen bei Kindern.

Surgical techniques for tachyarrhythmias refractory to medical treatment are used with increasing frequency. Among 211 patients undergoing antiarrhythmic surgery 10 children (2 to 14 years old) were operated by electrophysiologically directed procedures. 7 patients suffered from WPW syndrome, 2 from focal atrial tachycardias and 1 from recurrent ventricular tachycardia following the repair of Fallot's tetralogy. In all cases preoperative electrophysiologic study and intraoperative mapping preceded operative ablation. Surgical treatment consisted of interruption of the bundle of Kent (3 right-sided, 2 left-sided, 3 septal), ablation of the atrial focus (1 right-sided, 1 left-sided) and right ventricular outflow tract incision. In 7 operations cryo-techniques were added. 2 children with WPW syndrome had two interventions because of tachycardia recurrences due to multiple accessory pathways. In 1 case a VVI-pacemaker was implanted postoperatively due to complete atrioventricular block. Another 2 children with prolonged postoperative bradycardia received a pacemaker prophylactically. Only the child with previous tetralogy of Fallot is still under antiarrhythmic medication while all other children are free of tachycardiac episodes. Our data confirm the efficacy of surgical treatment of tachyarrhythmias in children thereby abolishing the need for life-long antiarrhythmic medication.

Site-specific tamoxifen-DNA adduct formation: lack of correlation with mutational ability in Escherichia coli.

We have mapped sites of tamoxifen adduct formation, in the lacI gene using the polymerase STOP assay, following reaction in vitro with alpha-acetoxytamoxifen and horseradish peroxidase (HRP)/H(2)O(2) activated 4-hydroxytamoxifen. For both compounds, most adduct formation occurred on guanines. However, one adenine, within a run of guanines, generated a strong polymerase STOP site with activated 4-hydroxytamoxifen, and a weaker STOP site with alpha-acetoxytamoxifen at the same location. In Escherichia coli the lac I gene reacted with 4-hydroxytamoxifen was more likely to be mutated (2 orders of magnitude) than when reacted with alpha-acetoxytamoxifen, despite the greater DNA adduct formation by alpha-acetoxytamoxifen. This correlates with the greater predicted ability of activated 4-hydroxytamoxifen adducts to disrupt DNA structure than alpha-acetoxytamoxifen adducts. For lac I reacted with activated 4-hydroxytamoxifen, a hot spot of base mutation was located in the region of the only adenosine adduct. No mutational hot spots were observed with alpha-acetoxytamoxifen. Our data clearly shows a lack of correlation between gross adduct number, as assayed by (32)P-postlabeling and mutagenic potential. These data indicate the importance of minor adduct formation in mutagenic potential and further that conclusions regarding the mutagenicity of a chemical may not be reliably derived from the gross determination of adduct formation.

[Ectopic atrial tachycardia: surgical therapy (case report and review of the literature)]. / Ektope atriale Tachykardie: Chirurgische Therapie (Fallbericht und Literaturübersicht).

Focal atrial tachycardia with frequencies up to 200/min in an 11-year-old girl had been resistant to drugs over a period of 5 years. An electrophysiological study demonstrated a left atrial ectopic tachycardia. Intraoperative epicardial mapping localized the automatic focus at the base of the left atrial appendage. Excision of the appendage and cryoablation of the adjacent area were performed using cardiopulmonary bypass. Histological examination of the excised tissue showed no specific alterations aside from islets of fatty tissue. The girl has been in sinus rhythm and has shown no tachycardias during the 6 months following the operation. Review of the literature covering 17 cases of right and 12 cases of left atrial focal tachycardia indicates excision of the atrial tissue in combination with cryoablation to be the treatment of choice to ensure success.

[Surgical treatment of Wolff-Parkinson-White syndrome--experiences with 87 surgically treated patients]. / Chirurgische Behandlung des Wolff-Parkinson-White-Syndroms--Erfahrungen mit 87 operierten Patienten.

Since January 1984, 87 patients (pts) (57 male, 30 female; age 3 to 64 years) with Wolff-Parkinson-White syndrome were operated upon. The indication for surgical treatment was documented recurrent, paroxysmal tachycardia refractory to medical treatment in 85 cases. Eleven pts (13%) had additional heart disease. 87 pts had a total of 103 accessory pathways (AP). AP was localized at the left free wall in 68% (70 AP), at the right free wall in 16% (16 AP), and localized septally in 17% (17 AP). Thirteen pts (15%) had multiple AP (10 pts had two and three pts had three AP). 87 AP were known preoperatively, 96 were localized intraoperatively, and seven were diagnosed during reoperation. Twenty-seven pts were left lateral AP were operated by the epicardial approach and 37 pts by the endocardial approach. Patients with right lateral AP were approached by an epicardial technique in six cases, and by a transmural technique in five. Cryotechnique was applied additionally in 85 pts. Twelve pts suffered recurrences, 11 were reoperated. 101 AP (98%) were dissected successfully, of which 13 (13%) were ablated during reoperation. All pts survived the initial operation. Two pts died after reoperation. One pt is pacemaker-dependent due to a persisting postoperative AV block. We conclude that surgical dissection of accessory pathways can now be offered as an alternative to the non-surgical treatment modes, with low risk and yielding a high success rate.

Estrogenic alkylphenols induce cell death by inhibiting testis endoplasmic reticulum Ca(2+) pumps.

Industrial alkylphenols in the environment may act as "xenoestrogens" to disrupt testicular development and decrease male fertility. Amongst possible targets for these compounds are testicular Sertoli cells, which nurture the developing sperm cells. We demonstrate that SERCA 2 and 3 Ca(2+) pumps are relatively abundant in rat testis microsomal membranes, and also in Sertoli, myoid, and TM4 cells (a Sertoli cell line). A number of estrogenic alkylphenols such as nonylphenol, octylphenol, bisphenol A, and butylated hydroxytoluene all inhibit testicular Ca(2+) ATPase in the low micromolar concentration range. These agents also mobilize intracellular Ca(2+) in intact TM4 cells in a manner consistent with the inhibition of ER Ca(2+) pumps. Alkylphenols dramatically decrease the viability of TM4 cells, an effect that is reversed by either a caspase inhibitor or by BAPTA, and is therefore consistent with Ca(2+)-dependent cell death via apoptosis. We postulate that alkylphenols disrupt testicular development by inhibiting ER Ca(2+) pumps, thus disturbing testicular Ca(2+) homeostasis.