PARP1-targeted fluorescence molecular endoscopy as novel tool for early detection of esophageal dysplasia and adenocarcinoma

BACKGROUND

Esophageal cancer is one of the 10 most common cancers worldwide and its incidence is dramatically increasing. Despite some improvements, the current surveillance protocol with white light endoscopy and random untargeted biopsies collection (Seattle protocol) fails to diagnose dysplastic and cancerous lesions in up to 50% of patients. Therefore, new endoscopic imaging technologies in combination with tumor-specific molecular probes are needed to improve early detection. Herein, we investigated the use of the fluorescent Poly (ADP-ribose) Polymerase 1 (PARP1)-inhibitor PARPi-FL for early detection of dysplastic lesions in patient-derived organoids and transgenic mouse models, which closely mimic the transformation from non-malignant Barrett's Esophagus (BE) to invasive esophageal adenocarcinoma (EAC).

METHODS

We determined PARP1 expression via immunohistochemistry (IHC) in human biospecimens and mouse tissues. We also assessed PARPi-FL uptake in patient- and mouse-derived organoids. Following intravenous injection of 75 nmol PARPi-FL/mouse in L2-IL1B (n = 4) and L2-IL1B/IL8Tg mice (n = 12), we conducted fluorescence molecular endoscopy (FME) and/or imaged whole excised stomachs to assess PARPi-FL accumulation in dysplastic lesions. L2-IL1B/IL8Tg mice (n = 3) and wild-type (WT) mice (n = 2) without PARPi-FL injection served as controls. The imaging results were validated by confocal microscopy and IHC of excised tissues.

RESULTS

IHC on patient and murine tissue revealed similar patterns of increasing PARP1 expression in presence of dysplasia and cancer. In human and murine organoids, PARPi-FL localized to PARP1-expressing epithelial cell nuclei after 10 min of incubation. Injection of PARPi-FL in transgenic mouse models of BE resulted in the successful detection of lesions via FME, with a mean target-to-background ratio > 2 independently from the disease stage. The localization of PARPi-FL in the lesions was confirmed by imaging of the excised stomachs and confocal microscopy. Without PARPi-FL injection, identification of lesions via FME in transgenic mice was not possible.

CONCLUSION

PARPi-FL imaging is a promising approach for clinically needed improved detection of dysplastic and malignant EAC lesions in patients with BE. Since PARPi-FL is currently evaluated in a phase 2 clinical trial for oral cancer detection after topical application, clinical translation for early detection of dysplasia and EAC in BE patients via FME screening appears feasible.

Positive Pressure versus Pressure Support Ventilation at Different Levels of PEEP Using the ProSeal™ Laryngeal Mask Airway

We compared positive pressure ventilation with pressure support ventilation at different levels of positive end expiratory pressure (PEEP) using the ProSeal laryngeal mask airway (PLMA). Forty-two anaesthetized adults (ASA 1-2, aged 19 to 63 years) underwent positive pressure ventilation and then pressure support ventilation each with PEEP set at 0, 5 and 10 cmH2O in random order. Pressure support ventilation was with the inspired tidal volume (VTInsp) set at 7 ml/kg and the respiratory rate adjusted to maintain the end-tidal CO2 (ETCO2) at 40 mmHg. Pressure support ventilation was with pressure support set at 5 cmH2O above PEEP and initiated when inspiration produced a 2 cmH2O reduction in airway pressure. Tidal volumes were similar during positive pressure and pressure support ventilation with PEEP, but were higher for the former without PEEP. Respiratory rate and peak inspiratory flow rate were higher during pressure support than positive pressure ventilation (all P<0.001). Peak airway pressure (Ppaw), mean airway pressure (Mpaw), peak expiratory flow rate, and expired airway resistance were lower during pressure support than positive pressure ventilation (all P<0.001). With PEEP set at 10 cmH2O, ETCO2 was lower for pressure support than positive pressure ventilation. During positive pressure ventilation, there was an increase in Ppaw, Mpaw and dynamic compliance (Cdyn) with increasing levels of PEEP (all P<0.01). During pressure support ventilation, there was an increase in inspired and expired tidal volume, Ppaw, peak inspiratory and expiratory flow rates and Cdyn, and a reduction in ETCO2, work of breathing, and expired airway resistance with increasing levels of PEEP (all P<0.01). There were no differences in SpO2, non-invasive mean arterial pressure, heart rate or leak fraction. We conclude that pressure support ventilation provides equally effective gas exchange as positive pressure ventilation during PLMA anaesthesia with or without PEEP at the tested settings. During pressure support, PEEP increases ventilation and reduces work on breathing without increasing leak fraction.

Kaniner und feliner Diabetes mellitus – ein epidemiologischer Rückblick (1996–2006)

Gegenstand und Ziel: Bestimmung der Prävalenz und Risikofaktoranalyse des Diabetes mellitus bei Hund und Katze am Patientenkollektiv der Tierärztlichen Hochschule Hannover. Material und Methoden: Retrospektiv wurden alle diabetischen Patienten der Klinik für Kleintiere der Tierärztlichen Hochschule Hannover in den Jahren 1996 bis 2006 nach Gewicht, Alter, Rasse und Geschlecht analysiert. Ergebnisse: In diesem 11-jährigen Untersuchungszeitraum litten 10 von 1000 Katzen und 4 von 1000 vorgestellten Hunden an Diabetes mellitus. Der feline Diabetes mellitus weist im Vergleich zum kaninen Diabetes mellitus eine steigende Tendenz auf. Im Geschlechtervergleich der Katzen repräsentieren kastrierte Kater mit 1,52% die größte Gruppe. Mit 0,79% sind kastrierte Hündinnen am häufigsten betroffen. Das Verhältnis von diabetischen Hündinnen zu Rüden liegt bei 2 : 1. Im Rassenvergleich ergibt sich bei Cairn Terrier und West Highland White Terrier eine erhöhte Inzidenz des Diabetes mellitus, während Schäferhunde und Dackel eine signifikant nierigere Prävalenz aufweisen. Schlussfolgerung: Die Prävalenz des Diabetes mellitus nimmt bei der Katze im Gegensatz zum Hund im norddeutschen Patientenkollektiv zu. An diesem Patientengut wurden folgende Risikofaktoren ermittelt: zunehmendes Alter, männliches Geschlecht und Gewicht für Katzen; mittleres Alter, weibliches Geschlecht und Kastration für Hunde. Klinische Relevanz: Die Entstehung des kaninen und felinen Diabetes mellitus ist multifaktoriell und daher nach wie vor eine große Herausforderung für Kliniker und Forscher. Aus diesem Grund kommt der Identifizierung von Risikofaktoren für das bessere Verständnis sowie die Erarbeitung neuer Präventionsmaßnahmen und Behandlungskonzepte herausragende Bedeutung zu.

Diffusion and precipitation processes in iron-based silica gardens

The time-dependent dynamic evolution of macroscopic silica garden tubes is shown to strongly depend on the used metal cations.

Evaluation of a rabies ELISA as an alternative method to seroneutralisation tests in the context of international trade of domestic carnivores

For several years, international movements with pets have greatly increased. Most countries have relaxed their quarantine measures and adopted a scheme combining vaccination of pets against rabies followed by a serological test to check the efficacy of vaccination. This new scheme has been strongly supported by the OIE, WHO and the European Commission to facilitate the free movement of people and pets around the world. Currently, only two reference methods are recognised and prescribed (the FAVN test and the RFFIT) to measure rabies antibody levels in serum samples for international trade. They are reliable and valuable methods of assessing the efficacy of rabies vaccination but they are time-consuming and require well-trained people and specialised laboratory facilities. A few years ago, an ELISA (Platelia™ Rabies II kit ad usum Veterinarium) was developed for domestic carnivores and wildlife. To our knowledge, this ELISA is the only one certified and prescribed by the OIE. Following its marketing, one task of the EURL for rabies serology was to evaluate the performance of laboratories using this new kit. The results revealed that 26% of the participants, which were already approved laboratories for rabies serology, failed the inter-laboratory trial. Such unsatisfactory results have never been observed during any of the previous proficiency tests organised annually since 2000 by the EURL for rabies serology using reference methods. More investigations were undertaken through internal and collaborative studies to assess the performance of this newly marketed ELISA kit. The results of the internal study revealed that even with a specificity of 100%, the sensitivity evaluated on 593 samples of domestic carnivores came to 78.2%. An issue regarding the underestimation of serum titres was also revealed during the study. The results of a collaborative study involving 23 international laboratories reinforced the preliminary conclusions regarding lack of sensitivity. Indeed, only 5 laboratories out of the 23 obtained satisfactory results. We therefore suggest adopting a threshold of 0.3 EU/mL instead of 0.5 EU/mL to increase the sensitivity of the test.

Craniotomy during ECMO in a severely traumatized patient

Extracorporeal membrane oxygenation (ECMO) can be a last resort treatment in acute respiratory distress syndrome after thoracic trauma. However, co-existent brain trauma is considered to be a contra-indication for ECMO. This is the first report on successful craniotomy under ECMO treatment in a multiply traumatized patient with severe thoracic and brain injuries. This successful treatment with beneficial neurological outcome suggests that ECMO therapy should not be withheld from severely injured patients with combined brain and thoracic trauma presenting with life-threatening hypoxemia. Moreover, even craniotomy may be performed during ECMO therapy without major bleeding and adverse effects on neurological function.

Cisatracurium, but not mivacurium, induces apoptosis in human umbilical vein endothelial cells in vitro

BACKGROUND AND OBJECTIVE

Cisatracurium is an intermediate acting, non-depolarizing neuromuscular blocking agent. Previous reports have indicated a growth-inhibitory effect of the isoforms cisatracurium and atracurium on two human cell lines in vitro. These effects were ascribed to oxidative stress elicited by acrylate esters formed during cisatracurium breakdown. Oxidative stress is a potent precipitator of apoptosis. Therefore, the aim of the present study was to investigate whether the growth-inhibitory effects of cisatracurium could be explained by initiation of apoptosis.

METHODS

Human umbilical vein endothelial cells were incubated with cisatracurium at concentrations of 0.96, 3.2, 9.6, 32 and 96 micromol for 24 h. DNA fragmentation was measured using the Cell Death Detection ELISA Plus assay (Roche Diagnostics, Mannheim, Germany).

RESULTS

There was a dose dependency of cisatracurium with respect to the rate of apoptosis in human umbilical vein endothelial cells. Programmed cell death could be demonstrated at concentrations encountered in human plasma after single-bolus injections of cisatracurium. Apoptosis was attenuated by the concomitant administration of glutathione.

CONCLUSIONS

These findings strongly support the hypothesis that acrylate esters, breakdown products of cisatracurium, induce oxidative stress and, subsequently, apoptosis.

Incidence of lower thoracic ligamentum flavum midline gaps † †Presented in abstract form at the IARS 78th Clinical and Scientific Congress, Tampa Bay, Florida, USA, 2004

BACKGROUND

Lower thoracic epidural anaesthesia and analgesia (EDA) has gained increasing importance in perioperative pain therapy. The loss-of-resistance technique used to identify the epidural space is thought to rely on the penetration of the ligamentum flavum. Investigations at the cervical and lumbar regions have demonstrated that the ligamentum flavum frequently exhibits incomplete fusion at different vertebral levels. Therefore, the aim of this study was to directly investigate the incidence of lower thoracic ligamentum flavum midline gaps in embalmed cadavers.

METHODS

Vertebral column specimens were obtained from 47 human cadavers. Ligamentum flavum midline gaps were recorded between the vertebral levels T6 and L1.

RESULTS

The incidence of midline gaps/number of viable specimens at the following levels was: T6-7: 2/45 (4.4%), T7-8: 1/47 (2.1%), T8-9: 2/45 (4.4%), T9-10: 7/39 (17.9%), T10-11: 12/34 (35.2%), T11-12: 10/35 (28.5%), T12/L1: 6/38 (15.8%).

CONCLUSIONS

In the present study we have determined the frequency of lower thoracic ligamentum flavum midline gaps. Gaps are less frequent than at cervical levels, but more frequent than at lumbar levels. Peak incidence was found in the region between T10 and T12. Using a strict midline approach, one cannot therefore rely on the ligamentum flavum to impede entering the epidural space in all patients.

Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study †

BACKGROUND

The cephalic antebrachial vein is often used for venous access. However, superficial radial arteries of the forearm are known and unintentional arterial puncture can result from attempts to cannulate the lateral veins of the arm.

METHODS

Accidental puncture of a superficial radial artery during peripheral venous cannulation prompted us to study the anatomy of 26 specimens and to assess the relationship between the radial artery and the cephalic vein in the forearm.

RESULTS

In two cases, we found accessory branches of the radial artery close to the cephalic forearm vein. Venous cannulation at the lateral wrist carries a small risk of arterial puncture if arterial anomalies are present.

CONCLUSIONS

If venous cannulation is attempted at the radial side of the wrist, palpation for pulsation should reduce the danger of arterial puncture.

Accuracy in estimating the correct intervertebral space level during lumbar, thoracic and cervical epidural anaesthesia

BACKGROUND

Even in the absence of factors concealing anatomical landmarks, high failure rates in correctly determining a given lumbar interspace have been reported.

METHODS

Therefore, it was the aim of the present study to compare the assessed and factual level (determined by computed tomography) of epidural puncture in attending a regional anaesthesia cadaver workshop. Eighty-two anaesthetists performed 117 punctures.

RESULTS

Vertebral interspaces between T8-L4 were correctly identified more often than those between C3-T5 (P < 0.05). Identification of an arbitrarily chosen vertebral interspace was excellent in both the cervical/high thoracic and thoracic/lumbar regions.

CONCLUSION

As previously conjectured only for the lumbar region, we could confirm the tendency of anaesthetists to perform neuraxial puncture more cranially than expected also for the thoracic and cervical regions. The large majority of punctures (93.7%) was performed within one interspace of the predicted level.

Sevoflurane in Exhaled Air of Operating Room Personnel

Evidence on potential health hazards arising from exposure to volatile anesthetics remains controversial. Exposure may, in principle, be supervised by monitoring of ambient air or, alternatively, in vivo. We used the Proton Transfer Reaction-Mass Spectrometry to screen the breath of 40 operating room staff members before operating room duty, 0, 1, 2, and 3 h after duty, and before commencing duty on the consecutive day, and control persons. Staff members exhibited significantly increased sevoflurane levels in exhaled air after duty, with a mean of 0.80 parts per billion as compared with baseline values of 0.26 parts per billion (P < 0.05). Analysis of variance with adjustment for within correlation (repeated measurements) showed a statistically significant time-effect (P < 0.001). We conclude that (a) Proton Transfer Reaction-Mass Spectrometry biomonitoring of exhaled sevoflurane can serve as a simple and rapid method to determine volatile anesthetic excretion after occupational exposure, and (b) significant concentrations of sevoflurane may be continuously present in persons exposed to sevoflurane on a daily basis.

IMPLICATIONS

The present study depicts the profile of volatile anesthetics, isoflurane and sevoflurane, in exhaled air of ambulatory patients. Biomonitoring of expired anesthetic concentrations is a noninvasive and rapid method to determine volatile anesthetic excretion.

Neopterin as a marker of immunostimulation: an investigation in anaesthetic workplaces

Personnel working in operating theatres and recovery rooms are exposed to a variety of noxious substances. The results of studies of the effects of occupational exposure on immune parameters are conflicting. Neopterin is an acknowledged marker of immunostimulation. Urinary neopterin levels of 58 anaesthetists and anaesthetic nurses were measured over a 3-week period. Neopterin analyses were performed using high performance liquid chromatography. Neopterin levels were within the normal range for all subjects. Younger subjects (aged < or = 35 years) had significantly higher urinary neopterin concentrations than older subjects (aged > 35 years). The present study is the first to investigate the influence of anaesthetic exposure on neopterin levels. No evidence of immunostimulation was found.

Monitoring pollution by proton-transfer-reaction mass spectrometry during paediatric anaesthesia with positive pressure ventilation via the laryngeal mask airway or uncuffed tracheal tube

Twenty children aged 2-66 months were randomly allocated for airway management with either the laryngeal mask airway or uncuffed tracheal tube using intermittent positive pressure ventilation with a tidal volume of 8 ml.kg-1 and a respiratory rate adjusted to maintain end-expiratory carbon dioxide concentration at 5.3 kPa. Induction was with fentanyl/propofol and maintenance was with sevoflurane 2.5% in oxygen/air. The airway device was removed when the patients were awake and the patients were transferred to the postanaesthesia care unit 10 min later. Air was sampled from a point 1.5 m above the floor at a location remote from the ventilation outlet and analysed using a proton-transfer-reaction mass spectrometer capable of continuous trace gas analysis at the parts per billion volume (ppbv) level. The concentration of sevoflurane was recorded every minute during three consecutive phases: for 5 min before the introduction of sevoflurane (background); after introduction of sevoflurane until removal of the airway device (intra-operative); and every minute after removal until the concentration returned to background levels. Median (interquartile range [range]) intra-operative sevoflurane concentrations were 200-400 times higher than background values for the laryngeal mask airway 1 (1-2 [0-3]) ppbv vs. 404 (278-523 [83-983]) ppbv, respectively, and the tracheal tube 2 (1-3 [0-5]) ppbv vs. 396 (204-589 [107-1735]) ppbv (both p < 0.0001), and returned to background values within 5 min of removal. There were no differences in sevoflurane concentration between devices intra-operatively or after removal. The performance of the proton-transfer-reaction mass spectrometer was identical at the start and end of the 30-day study. We conclude that peri-operative sevoflurane concentration in a modern operating theatre is similar for the laryngeal mask airway and the uncuffed tracheal tube in paediatric patients receiving intermittent positive pressure ventilation. Intra-operative sevoflurane concentrations are five times lower than occupational safety limit requirements, and 1000 times lower 5 min after removal of the airway device with the patient awake. The proton-transfer-reaction mass spectrometer has potential for monitoring air quality in the operating theatre.

Monitoring of immune activation using biochemical changes in a porcine model of cardiac arrest

In animal models, immune activation is often difficult to assess because of the limited availability of specific assays to detect cytokine activities. In human monocytes/macrophages, interferon-gamma induces increased production of neopterin and an enhanced activity of indoleamine 2,3-dioxygenase, which degrades tryptophan via the kynurenine pathway. Therefore, monitoring of neopterin concentrations and of tryptophan degradation can serve to detect the extent of T helper cell 1-type immune activation during cellular immune response in humans. In a porcine model of cardiac arrest, we examined the potential use of neopterin measurements and determination of the tryptophan degradation rate as a means of estimating the extent of immune activation. Urinary neopterin concentrations were measured with high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) (BRAHMS Diagnostica, Berlin, Germany). Serum and plasma tryptophan and kynurenine concentrations were also determined using HPLC. Serum and urine neopterin concentrations were not detectable with HPLC in these specimens, whereas RIA gave weakly (presumably false) positive results. The mean serum tryptophan concentration was 39.0 +/- 6.2 micromol/l, and the mean kynurenine concentration was 0.85 +/- 0.33 micromol/l. The average kynurenine-per-tryptophan quotient in serum was 21.7 +/- 8.4 nmol/micromol, and that in plasma was 20.7 +/- 9.5 nmol/micromol (n = 7), which corresponds well to normal values in humans. This study provides preliminary data to support the monitoring of tryptophan degradation but not neopterin concentrations as a potential means of detecting immune activation in a porcine model. The kynurenine-per-tryptophan quotient may serve as a short-term measurement of immune activation and hence permit an estimate of the extent of immune activation.

The influence of atracurium, cisatracurium, and mivacurium on the proliferation of two human cell lines in vitro

We tested the influence of atracurium and cisatracurium (final concentrations: 0, 0.96, 3.2, 9.6, 32, and 96 microM) on proliferation of human cells (hepatoma HepG2 cells and human umbilical vein endothelial cells) in vitro. In additional experiments, glutathione, N-acetylcysteine, or carboxyl esterase was added before the addition of either relaxant. The number of cells counted after 72 h of incubation was expressed as a percentage of the mean cell number in wells incubated without additives. Atracurium and cisatracurium progressively decreased cell proliferation in a concentration-dependent pattern. With human umbilical vein endothelial cells, atracurium or cisatracurium (3.2 microM) decreased the cell count to 67.7 % (SD, 14.8%) and 50% (SD, 8.6%), respectively. Cell proliferation was not inhibited by mivacurium. The results were similar to those with HepG2 cells. Glutathione, N-acetylcysteine, and carboxyl esterase partially reversed the effects of atracurium and cisatracurium. When incubated in a buffer with glutathione, atracurium decreased the number of glutathione-sulfhydryl groups. The findings that atracurium and cisatracurium inhibit proliferation of human cell lines in vitro, but that mivacurium does not, and that this effect is alleviated by glutathione and N-acetylcysteine, as well as by the carboxyl esterase, indicate that the inhibition may be caused by the reactive acrylate metabolites.

Human breath isoprene and its relation to blood cholesterol levels: new measurements and modeling

Numerous publications have described measurements of breath isoprene in humans, and there has been a hope that breath isoprene analyses could be a noninvasive diagnostic tool to assess blood cholesterol levels or cholesterol synthesis rate. However, significant analytic problems in breath isoprene analysis and variability in isoprene levels with age, exercise, diet, etc., have limited the usefulness of these measurements. Here, we have applied proton transfer reaction-mass spectrometry to this problem, allowing on-line detection of breath isoprene. We show that breath isoprene concentration increases within a few seconds after exercise is started as a result of a rapid increase in heart rate and then reaches a lower steady state when breath rate stabilizes. Additional experiments demonstrated that increases in heart rate associated with standing after reclining or sleeping are associated with increased breath isoprene concentrations. An isoprene gas-exchange model was developed and shows excellent fit to breath isoprene levels measured during exercise. In a preliminary experiment, we demonstrated that atorvastatin therapy leads to a decrease in serum cholesterol and low-density-lipoprotein levels and a parallel decrease in breath isoprene levels. This work suggests that there is constant endogenous production of isoprene during the day and night and reaffirms the possibility that breath isoprene can be a noninvasive marker of cholesterologenesis if care is taken to measure breath isoprene under standard conditions at constant heart rate.

Analysing ventricular fibrillation ECG-signals and predicting defibrillation success during cardiopulmonary resuscitation employing N(alpha)-histograms

Mean fibrillation frequency may predict defibrillation success during cardiopulmonary resuscitation (CPR). N(alpha)-histogram analysis should be investigated as an alternative. After 4 min of cardiac arrest, and 3 versus 8 min of CPR, 25 pigs received either vasopressin or epinephrine (0.4, 0.4, and 0.8 U/kg vasopressin versus 45, 45, and 200 microg/kg epinephrine) every 5 min with defibrillation at 22 min. Before defibrillation, the N(alpha)-parameter histogramstart/histogramwidth and the mean fibrillation frequency in resuscitated versus non-resuscitated pigs were 2.9+/-0.4 versus 1.7+/-0.5 (P=0.0000005); and 9.5+/-1.7 versus 6.9+/-0.7 (P=0.0003). During the last minute prior to defibrillation, histogramstart/histogramwidth of > or =2.3 versus mean fibrillation frequency > or =8 Hz predicted successful defibrillation with subsequent return of a spontaneous circulation for more than 60 min with sensitivity, specificity, positive predictive value and negative predictive value of 94 versus 82%, 96 versus 89%, 98 versus 93% and 90 versus 74%, respectively. We conclude, that N(alpha)-analysis was superior to mean fibrillation frequency analysis during CPR in predicting defibrillation success, and distinction between vasopressin versus epinephrine effects.

Nitric oxide-dependent apoptosis in ovarian carcinoma cell lines

OBJECTIVE

In a recent study, we found different profiles of inducible nitric oxide synthase (iNOS) gene expression in the ovarian carcinoma cell lines OVCAR-3, HOC-7, and 2774 following stimulation by proinflammatory cytokines. The present study was performed to determine whether nitric oxide (NO) synthesis correlates with programmed cell death in these cells.

METHODS

NO-Dependent apoptosis was detected by DNA fragmentation analysis and fluorescence-activated cell sorter analysis.

RESULTS

NO formation in response to interferon gamma (IFN-gamma), interleukin-1beta (IL-1beta), and tumor necrosis factor alpha (TNF-alpha) was correlated with programmed cell death in the investigated cells. DNA fragmentation was most prominent in OVCAR-3 (34.17 +/- 1.81%), less pronounced in HOC-7 (12.86 +/- 0.45%), and undetectable in 2774 (4.54 +/- 0.40%) cells. The rate of apoptosis correlated with the amount of NO formation in cytokine-treated cells. Moreover, coincubation of OVCAR-3 and HOC-7 with the specific iNOS inhibitor aminoguanidine suppressed apoptosis induced by IFN-gamma, IL-1beta, and TNF-alpha.

CONCLUSION

Our data indicate that in OVCAR-3 and HOC-7 cells, NO synthesis induced by IFN-gamma, IL-1beta, and TNF-alpha is correlated with the degree of apoptotic cell death. In clinical situations, this might in part explain the benefit of cytokine application in ovarian carcinoma patients (e.g., documented for IFN-gamma).

Analysis of volatile organic compounds: possible applications in metabolic disorders and cancer screening

The human breath contains a variety of endogenous volatile organic compounds (VOCs). The origin and pathophysiological importance of these VOCs is poorly investigated. Little is known about the interaction of VOCs from ambient air, such as those produced by plants and exhaust fumes, with the human organism. Gas chromatographic determination of VOC concentrations is tedious. Proton-transfer-mass spectroscopy (PTR-MS), a new technology for the online detection of VOC patterns, is a valuable alternative. We present two interesting molecular species, isoprene and ortho (o)-toluidine, as examples of endogenously produced VOCs. In a case study, breath isoprene reductions during lipid-lowering therapy (36%) were shown to correlate with cholesterol (32%) and LDL concentrations (35%) in blood (p < 0.001) over a period of 15 days. Therefore, isoprene concentrations in human breath (measured by PTR-MS) might serve as an additional parameter to complement invasive tests for controlling lipid-lowering therapy. Furthermore, it may be a useful parameter for lipid disorder screening. Mass-108, which presumably represents o-toluidine in our breath samples, was found in significantly higher concentrations in the breath of patients with different tumors (1.5 +/- 0.8 ppbv) than in age-matched controls (0.24 +/- 0.1 ppbv, p < 0.001). Inflammatory reactions do not seem to alter the pattern of mass-108. Therefore, it appears to be a currently underestimated carcinoma marker that deserves further investigation.

Online monitoring of air quality at the postanesthetic care unit by proton-transfer-reaction mass spectrometry

The subthreshold exposure to trace anesthetic gases is not associated with considerable risk of adverse health effects. Online control of ambient air exchange at the postoperative workplace may help in supervising air quality and lead to cost reduction. A proton-transfer-reaction mass spectrometer system was used for online monitoring of volatile organic compounds, especially anesthetic gases. The mean exposure to sevoflurane and isoflurane at the urological postanesthesia care unit (PACU) was 15.9 and 9.5 parts per billion, respectively. Sevoflurane and isoflurane concentrations at the urological PACU showed a patient turnover-dependent burden during our investigation period. Because modern PACUs have a high ventilation capacity, the 24-h occupational burden by anesthetic gases at the PACU is relatively low. Monitoring and controlling of ambient air by automatic built-in alarm systems would be useful for quality control of the postoperative workplace. Moreover, energy costs of ventilation systems could be reduced by coupling ventilation capacity to the effective exposure.

Different patterns of inducible nitric oxide synthase gene expression in ovarian carcinoma cell lines

BACKGROUND

Stimulation of inducible nitric oxide synthase (iNOS) and release of nitric oxide by tumor cells may play a critical role in cancer development, either by exhibiting tumoricidal effects or by promoting tumor progression.

MATERIALS AND METHODS

In the present study, we investigated four ovarian carcinoma cell lines with respect to their iNOS expressing characteristics.

RESULTS

Following incubation with interferon-gamma, tumor necrosis factor-alpha and interleukin-1 beta, a marked stimulation of iNOS gene expression was found in SKOV-6 and OVCAR-3 cells, while only minor iNOS synthesis was detectable in HOC-7. Time-dependent accumulation of nitrite/nitrate in the culture supernatant indicated that the three cell lines were stimulated to produce and release nitric oxide. In contrast, no NO generation was observed in the fourth cell line under investigation, 2774.

CONCLUSION

Due to the growth regulatory functions attributed to NO, variations in NO production may be of importance e.g. following interferon-gamma therapy in patients with ovarian cancer.

Neopterin-induced expression of intercellular adhesion molecule-1 (ICAM-1) in type II-like alveolar epithelial cells

Production and release of proinflammatory mediators such as tumour necrosis factor-alpha and neopterin are common events following the activation of the cellular immune system. Concerning inflammatory disorders of the lung, e.g. sepsis or sarcoidosis, high serum neopterin levels have been reported to correlate well with the severity of the disease. These situations are often associated with an increased expression of ICAM-1 reported to be induced in type II alveolar epithelial cells. In our study we investigated the potential effects of neopterin on ICAM-1 synthesis in the type II-like pneumocyte cell line L2. Detection of ICAM-1 gene expression by reverse transcriptase-polymerase chain reaction revealed a dose-dependent effect of neopterin, with maximum impact following 12-h incubations. Comparable results were obtained when ICAM-1 protein synthesis was measured via a cell-based ELISA. In a second set of experiments we were able to show that coincubation of L2 cells with pyrrolidine dithiocarbamate (PDTC) significantly suppressed neopterin-induced ICAM-1 synthesis. Since PDTC is known to be a potent inhibitor of NF-kappaB, the stimulating effects of neopterin on ICAM-1 gene expression and protein generation may be mediated by activation of this transcription factor. From these data we conclude that neopterin stimulates ICAM-1 production in L2 cells. In vivo, these effects may contribute to the prolongation of the inflammatory response, including cytotoxic cell host defence mechanisms that impair the functions of the airway epithelium.

Depot medroxyprogesterone acetate use in inner-city, minority adolescents: continuation rates and characteristics of long-term users

OBJECTIVE

To identify continuation rates of depot medroxyprogesterone acetate (Depo-Provera) and characteristics of long-term users in a population of inner-city, minority adolescents with high pregnancy rates.

DESIGN

Retrospective medical record review.

SETTING

An inner-city adolescent clinic and an adolescent pregnancy program.

METHODS

A review of the medical records of 250 females aged 13 to 20 years (mean +/- SD, 16.8 +/- 1.1 years), 62.9% Hispanic and 34.2% African American, receiving a first depot medroxyprogesterone acetate injection for contraception between August 1993 and June 1996 was conducted using a standardized form. The mean +/- SD age at menarche of the subjects was 11.6 +/- 1.4 years, and the mean +/- SD age at first intercourse was 14.1 +/- 1.3 years; the mean number of lifetime sex partners was 2.4. Of the subjects, 73.6% had used condoms, 32.0% used oral contraceptives, and none used implants. Of the 201 subjects for whom there were data in the medical records regarding prior fertility, 172 (85.6%) had been pregnant, and 145 (72.1%) had a child. Life table analysis was used to measure depot medroxyprogesterone acetate continuation rates and to compare subgroups of adolescents.

RESULTS

Depot medroxyprogesterone acetate continuation rates were found to be 70.3% at 6 months, 48.3% at 9 months, 31.5% at 12 months, and 12.8% at 24 months. The most common reason for depot medroxyprogesterone acetate discontinuation was missed appointments (41.7%). Subjects were followed up for a mean +/- SD of 1.3 +/- 0.7 years after discontinuation of depot medroxyprogesterone acetate use; 46.7% became pregnant. Among those 156 adolescents who discontinued depotmedroxyprogesterone acetate use, 40.0% restarted the method at some later time. Continuation of depot medroxyprogesterone acetate use was more likely if age at first intercourse was younger than 13 years (P = .04). Continuation rates were not related to age, ethnicity, age at menarche, number of sex partners, use of other contraceptives, prior pregnancy, or having a child.

CONCLUSIONS

In this study, just less than one third of the adolescents continued depot medroxyprogesterone acetate use for 1 year or longer. This suggests that depot medroxyprogesterone acetate does not function as a long-term method for most inner-city adolescents. The only characteristic that was associated with successful continuation of depot medroxyprogesterone acetate use was young age at first intercourse, implying that experience may be the main determinant of continuation.

Update on pubertal development

This review provides updated information relating to the timing of pubertal onset from a large study of girls seen in pediatric practices. In addition, new studies investigating the relationship of the hormone leptin to the onset of puberty are discussed, as well as new information on the neuroendocrine control of pubertal regulation. A provocative study documenting poor mental health, more behavior problems, and lower IQ in children with premature adrenarche when compared with controls raises the question of whether psychological stress triggers premature adrenarche or whether the early increase in adrenal hormone secretion causes psychosocial problems. Finally, significant advances in the management of central precocious puberty in girls have been made over the past year.

The use of nonhormonal methods of contraception in adolescents

Although the 1990s have seen a reduction in unintended pregnancy rates and improved contraceptive-use rates, the negative consequences of unintended pregnancy and STD acquisition continue to plague our youth. Primary health care providers, including pediatricians, play an essential role in further reducing unintended teen pregnancy and STD acquisition rates through the promotion of effective and consistent contraception. Pediatricians need to be aware that now, more than ever, nonhormonal contraceptive methods should be used by every sexually active youth, and counseling of both boys and girls should be routine. Although not as effective at preventing pregnancy as hormonal methods of contraception, many nonhormonal methods provide excellent STD protection. Condoms plus spermicide continue to be a very popular and effective method of pregnancy and STD prevention. The newer polyurethane male and female condoms provide alternative, safe barrier protection, although their efficacy at preventing HIV in vivo needs further study. Diaphragms and cervical caps, in conjunction with spermicide, also provide pregnancy and STD prevention, but not as effectively as male condoms plus spermicide. Although most likely to use condoms in association with another birth control method, adolescents often find dual-method use cumbersome and difficult to comply with. Finally, although IUDs and periodic abstinence are safe methods of birth control for older women in monogamous relationships, they are unlikely to be appropriate for most adolescents. In many respects, we have come full circle back to our "nonhormonal contraceptive roots." As we enter the twenty-first century, we have found that no single "miracle" approach can be used to reduce adolescent pregnancy and STD rates. Rather, pediatricians are obliged to offer nonhormonal methods of contraception, often in conjunction with other birth control methods, as a means of preventing unwanted STDs and pregnancy. Through a comprehensive community approach that uses sex education, abstinence programs, condom-availability programs, and contraceptive-skills training, however, pediatricians can play a central role in the promotion of effective and consistent contraception by adolescents.

Human dermal microvascular endothelial cells express inducible nitric oxide synthase in vitro

Stimulation of inducible nitric oxide synthase with subsequent release of nitric oxide in large amounts may play a critical part either in host defense reactions or in the pathophysiology of the inflammatory response syndrome leading to septic shock. The aim of the present study was to investigate whether human dermal microvascular endothelial cells exhibit the typical characteristics of an inducible nitric oxide synthase expressing cell. A strong effect on inducible nitric oxide synthase gene expression could be detected when the cells were coincubated with the proinflammatory cytokines interferon-gamma and tumor necrosis factor-alpha with inducible nitric oxide synthase cDNA concentrations averaging 11.7 +/- 0.6 amol per microg total RNA at 24 h, and 25.0 +/- 1.4 amol per microg total RNA at 48 h, respectively. Intracellular staining with an antibody recognizing inducible nitric oxide synthase protein and subsequent analysis by flow cytometry revealed a 4-fold increase of inducible nitric oxide synthase protein in human dermal microvascular endothelial cells treated with interferon-gamma/tumor necrosis factor-alpha. This was accompanied by a significant elevation in nitrite/nitrate concentrations in the cell-free culture supernatants. Our results indicate that human dermal microvascular endothelial cells are provided with an inducible nitric oxide synthase system and can be regarded as an appropriate cell model for investigating inducible nitric oxide synthase gene expression and nitric oxide properties in microvascular endothelial cells.

Neopterin-induced tumor necrosis factor-alpha synthesis in vascular smooth muscle cells in vitro

Synthesis and secretion of proinflammatory mediators like tumor necrosis factor-alpha and neopterin are common events in severe systemic inflammatory disorders, e.g. sepsis and septic shock. Recent data suggest that both substances show similarities with respect to their bioactivities. In the present study we investigated the potential interactions of neopterin and tumor necrosis factor-alpha on inducible nitric oxide synthase gene expression and nitric oxide generation in rat vascular smooth muscle cells. In addition, we studied the influence of neopterin on tumor necrosis factor-alpha synthesis in this cell type. Single stimulation of smooth muscle cells with either neopterin or tumor necrosis factor-alpha caused inducible nitric oxide synthase gene expression and nitric oxide production. Coincubation of cells with both compounds resulted in at least additive effects on nitric oxide synthesis. Quantification of tumor necrosis factor-alpha cDNA revealed a dose-dependent effect of neopterin on tumor necrosis factor-alpha gene expression. Similar results were obtained concerning the detection of tumor necrosis factor-alpha protein and the assessment of tumor necrosis factor-alpha bioactivity. These data suggest that neopterin and tumor necrosis factor-alpha are closely associated with regard to synthesis and effects, respectively. The interactions of both inflammatory mediators in vascular smooth muscle cells might contribute to the excessive release of nitric oxide observed during sepsis, thus triggering cellular destruction and multiple organ failure.

Neopterin induces nitric oxide-dependent apoptosis in rat vascular smooth muscle cells

Numerous studies indicate that proinflammatory substances like tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) as well as macrophage-derived neopterin are increased in atherosclerotic tissue and thus are potentially involved in the process of atherogenesis. Since apoptotic death of vascular smooth muscle cells (VSMC) is reported to occur in atherosclerotic lesions, we investigated the effects of neopterin, TNF-alpha, and IFN-gamma on apoptosis in cultured VSMC. Morphological changes characteristic of apoptosis as well as DNA fragmentation were detected in cells treated with neopterin, TNF-alpha/IFN-gamma, and neopterin + TNF-alpha/IFN-gamma. Simultaneously, neopterin, TNF-alpha/IFN-gamma, and neopterin + TNF-alpha/IFN-gamma led to inducible nitric oxide synthase (iNOS) gene expression and nitric oxide (NO) synthesis. NO generation was significantly reduced when cells were cotreated with the competitive iNOS inhibitor aminoguanidine. This was accompanied by decreased percentual apoptosis as detected by FACS analysis using all kinds of stimuli. We conclude that neopterin as well as TNF-alpha/IFN-gamma are potent mediators of apoptotic death in VSMC which is at least in part triggered by NO synthesis induced by these proinflammatory mediators.

The simultaneous quantitative determination of total, 'active', acetylated and conjugated sulfonamide in biological fluids

Methods are proposed which, in combination with those described in an earlier publication by the author, enable the separate determination of the two main types of sulfonamide metabolites, the N4-acetyl derivative and the conjugates, besides the total and the active sulfonamide in body fluids.