The B-APNEIC score: distilling the STOP-Bang questionnaire to identify patients at high risk for severe obstructive sleep apnoea

The STOP-Bang questionnaire is an established clinical screening tool to identify the risk of having mild, moderate or severe obstructive sleep apnoea using eight variables. It is unclear whether all eight variables contribute equally to the risk of clinically significant obstructive sleep apnoea. We analysed each variable for its contribution to detecting obstructive sleep apnoea; based on the results, we investigated whether the STOP-Bang questionnaire could be abbreviated to identify patients at high risk for severe obstructive sleep apnoea. We recruited patients with suspected obstructive sleep apnoea who were referred for overnight polysomnography. We used multivariable logistic regression to investigate the association of STOP-Bang parameters with severe obstructive sleep apnoea based on clinical and polysomnography data. Regression estimates were used to select variables to create the novel B-APNEIC score. We constructed receiver operating characteristic curves for the STOP-Bang questionnaire and B-APNEIC scores to identify patients with severe obstructive sleep apnoea and compared the areas under the curve using the DeLong method. Of the 275 patients enrolled, 32% (n = 88) had severe obstructive sleep apnoea. Logistic regression demonstrated that neck circumference (OR 2.20; 95%CI 1.10-4.40, p = 0.03) was the only variable independently associated with severe obstructive sleep apnoea. Observed apnoea during sleep, blood pressure and body mass index were the three next most closely trending predictors of severe obstructive sleep apnoea and were included along with neck circumference in the B-APNEIC score. Receiver operating curves demonstrated that the areas under the curve for STOP-Bang vs. B-APNEIC were comparable for identifying patients with severe obstructive sleep apnoea (OR 0.75; 95%CI 0.68-0.81 vs. OR 0.75; 95%CI 0.68-0.81: p = 0.99, respectively). Our results suggest that the B-APNEIC score is a simplified adaptation of the STOP-Bang questionnaire with equivalent effectiveness in identifying patients with severe obstructive sleep apnoea. Further studies are needed to validate and build on our findings.

Use of Helmet CPAP in COVID-19 - A practical review

Helmet CPAP (H-CPAP) has been recommended in many guidelines as a noninvasive respiratory support during COVID-19 pandemic in many countries around the world. It has the least amount of particle dispersion and air contamination among all noninvasive devices and may mitigate the ICU bed shortage during a COVID surge as well as a decreased need for intubation/mechanical ventilation. It can be attached to many oxygen delivery sources. The MaxVenturi setup is preferred as it allows for natural humidification, low noise burden, and easy transition to HFNC during breaks and it is the recommended transport set-up. The patients can safely be proned with the helmet. It can also be used to wean the patients from invasive mechanical ventilation. Our article reviews in depth the pathophysiology of COVID-19 ARDS, provides rationale of using H-CPAP, suggests a respiratory failure algorithm, guides through its setup and discusses the issues and concerns around using it.

International multicentre review of perioperative management and outcome for catecholamine-producing tumours

BACKGROUND

Surgery for catecholamine-producing tumours can be complicated by intraoperative and postoperative haemodynamic instability. Several perioperative management strategies have emerged but none has been evaluated in randomized trials. To assess this issue, contemporary perioperative management and outcome data from 21 centres were collected.

METHODS

Twenty-one centres contributed outcome data from patients who had surgery for phaeochromocytoma and paraganglioma between 2000 and 2017. The data included the number of patients with and without α-receptor blockade, surgical and anaesthetic techniques, complications and perioperative mortality.

RESULTS

Across all centres, data were reported on 1860 patients with phaeochromocytoma or paraganglioma, of whom 343 underwent surgery without α-receptor blockade. The majority of operations (78·9 per cent) were performed using minimally invasive techniques, including 16·1 per cent adrenal cortex-sparing procedures. The cardiovascular complication rate was 5·0 per cent overall: 5·9 per cent (90 of 1517) in patients with preoperative α-receptor blockade and 0·9 per cent (3 of 343) among patients without α-receptor blockade. The mortality rate was 0·5 per cent overall (9 of 1860): 0·5 per cent (8 of 517) in pretreated and 0·3 per cent (1 of 343) in non-pretreated patients.

CONCLUSION

There is substantial variability in the perioperative management of catecholamine-producing tumours, yet the overall complication rate is low. Further studies are needed to better define the optimal management approach, and reappraisal of international perioperative guidelines appears desirable.

Influence of Tree Size and Application Rate on Expression of Thiamethoxam in Citrus and Its Efficacy Against Diaphorina citri (Hemiptera: Liviidae)

Neonicotinoids are a key group of insecticides used to manage Diaphorina citri Kuwayama (Hemiptera: Liviidae), in Florida citrus. Diaphorina citri is the vector of Candidatus Liberibacter asiaticus, the presumed causal agent of huanglongbing, a worldwide disease of citrus. A two-season field study was conducted to evaluate the effect of tree size and application rate on the expression of thiamethoxam in young citrus following application to the soil. D. citri adult and nymph abundance was also correlated with thiamethoxam titer in leaves. Tree size and application rate each significantly affected thiamethoxam titer in leaf tissue. The highest mean thiamethoxam titer observed (33.39 ppm) in small trees (mean canopy volume = 0.08 m3) occurred after application of the high rate (0.74 g Platinum 75SG per tree) tested. There was a negative correlation between both nymph and adult abundance with increasing thiamethoxam titer in leaves. A concentration of 64.63 ppm thiamethoxam was required to reach a 1% probability of encountering a flush shoot with at least one adult D. citri, while 19.05 ppm was required for the same probability of encountering nymphs. The LC90 for the field population was 7.62 ppm thiamethoxam when administered through ingestion. Exposure to dosages as low as 7.62 ppm would likely result in sublethal exposure of some proportion of the population, which could exacerbate resistance development. Based on our results, subsequent work should investigate the use of neonicotinoids by foliar rather than soil application to maintain the chemical class in future insecticide management programs in Florida citrus.

Potential export of soluble reactive phosphorus from a coastal wetland in a cold-temperate lagoon system: Buffer capacities of macrophytes and impact on phytoplankton

The main pathways for phosphorus flux from land to sea are particle-associated (erosion) and dissolved runoff (rivers, groundwater, and agricultural drainage systems). These pathways can act as diffused sources for aquatic systems and support primary production, therefore, counteracting the efforts aimed at reducing phosphorus input from point sources such as sewage treatment plants. Phosphorus supports primary production in the water column and can elevate phytoplankton and macrophyte growth. Coastal wetlands with emerged (Phragmites australis) and submerged (Stuckenia pectinata and Chara sp.) macrophytes can affect phosphorus fluxes in the land-water transitional zone. The macrophytes have the potential to act as a buffer for phosphorus run-off. The aim of this study was to determine the phosphorus stocks in the transitional land-sea zone of a cold temperate lagoon at the southern Baltic Sea. Phosphorus in macrophytes, water samples, and phytoplankton growth were analyzed along a gradient moving away from the wetland. The phosphorus stocks in the above ground biomass of the Phragmites plants were the highest at the end of August and with more than 8000mgPm^-2 in the interior zone of the wetland, threefold the amount of P in Phragmites plant tissue at the wetland fringe. The submerged macrophytes stored only 300mgPm^-2, close to the wetland. Concentrations of soluble reactive phosphorus in the water column were higher in the zones of emerged macrophytes than in the zones of submerged macrophytes and decreased along the land-sea transect. Phytoplankton could grow proximal to the wetland during all seasons, but not further away. This study indicates that macrophytes can act as phosphorus sinks. However, short-term releases of phosphate within the Phragmites wetland have the potential to lead to phytoplankton growth. Phytoplankton can use these nutrient pulses either immediately or later, and support high biomass and turbidity within the system.

The correlation between body mass index, limb circumferences and blood pressure cuff fit in bariatric surgical patients

Introduction:

The purpose of this study was to determine the correlation between body mass index (BMI) and upper and lower arm as well as lower leg circumferences and the frequency of correct blood pressure (BP) cuff fit. We explored recommendations for the most likely BP cuff size and location for the three BMI categories.

Materials and Methods:

Following IRB approval we retrospectively analyzed a research database of bariatric surgical patients with a BMI of ≥40 kg/m². Data included patients’ characteristics, upper and lower arm as well as lower leg circumferences. Patients were divided into three groups based on BMI (kg/m², Group I: <45, Group II: 45-55, and Group III: >55). Appropriate cuff fit using a standard or large adult BP cuff (CRITIKON^®, GE Healthcare, Waukesha, Wisconsin, USA) on the upper and lower arm, and lower leg was determined. We analyzed the percent proportion of proper cuff fit for cuff sizes and locations between groups using appropriate nonparametric testing.

Results:

Limb circumference correlated significantly with BMI (P = 0.01), and the upper arm correlated most closely (r = 0.76). A standard adult BP cuff on the lower arm fit properly in >90% and >80% and in Groups I and II, respectively. A large cuff on the lower arm was appropriate in 87% of Group III. In two participants, a large cuff fit properly on the lower leg.

Discussion:

Limb circumference significantly correlated with BMI. Recommendations for proper cuff fit in different BMI categories can be made.

Enhancement and monitoring of pollutant removal in a constructed wetland by microbial electrochemical technology

A bench-scale constructed wetland combined with microbial electrochemical technology (MET-CW) was run for 400days with groundwater contaminated with benzene, methyl-tert-butyl ether (MTBE), and ammonium (NH4(+)). Four vertically stacked anode modules were embedded into a sand bed and connected with a stainless steel cathode placed in an open water pond. In the zone of presence of anode modules, significantly more benzene and MTBE were removed in the MET-CW compared to the control CW without MET in the first 150 operation days. Benzene was identified as primary electron donor at the anode. Benzene removal and current densities were linearly correlated, implying the potential of the system for electrochemically monitoring benzene biodegradation. Compound-specific isotope analysis (CSIA) indicated that benzene was initially activated by monohydroxylation forming intermediates which were subsequently oxidized accompanied by extracellular electron transfer, leading to current production. NH4(+) removal was not stimulated by MET.

Association of metabolic syndrome and surgical factors with pulmonary adverse events, and longitudinal mortality in bariatric surgery

BACKGROUND

Postoperative pulmonary complications (PPC) in bariatric surgery have not been well studied. Additionally, many bariatric patients suffer from the metabolic syndrome (MetS), contributing to surgical risk. We examined the incidence of PPC and MetS in a large national bariatric database. Furthermore, we analysed the relationships between morbidity, mortality, PPC, MetS, and several other comorbidities and also surgical factors.

METHODS

The Bariatric Outcomes Longitudinal Database (BOLD™) is a registry that includes up to 365 day outcomes. We analysed data between January 2008 and October 2010. The PPC tracked included pneumonia, atelectasis, pleural effusion, pneumothorax, adult respiratory distress syndrome, and respiratory failure. A composite pulmonary adverse event (CPAE) included the occurrence of any of these. MetS was defined as the combination of hypertension, dyslipidaemia, and diabetes mellitus. The association of MetS and additional comorbibities, procedural data, and patient characteristics with CPAEs was examined with appropriate statistical tests.

RESULTS

A total of 158 405 patients had a low incidence of PPC (0.91%) and a low mortality (0.6%) after bariatric surgery. MetS was prevalent in 12.7%, and was a significant risk factor for CPAE and mortality. Age, BMI, ASA physical status classification, surgical duration, procedure type, MetS (P<0.001), and additional comorbidities were significantly associated with CPAEs.

CONCLUSIONS

The incidence of PPC was low after bariatric surgery. Increasing age, BMI, ASA status, MetS, obstructive sleep apnoea, asthma, congestive heart failure, surgical duration, and procedure type were independently significantly associated with PPC. Pulmonary complications and MetS were significantly associated with increased postoperative mortality.

Intraoperative fluid and pharmacologic management and the anesthesiologist's supervisory role for nontraditional technologies during liver transplantation: a survey of US academic centers

BACKGROUND

Volume resuscitation and use of vasoactive medications during liver transplantation has not been systematically assessed. Furthermore, the anesthesiologist's role for intraoperative oversight of technologies such as renal replacement therapy and procedures such as venovenous bypass is poorly defined, and it is unclear if the center's annual transplant frequency affects these practices.

METHODS

We conducted a database analysis of the Liver Transplant Anesthesia Consortium survey 202 that addresses these questions. Data from US academic liver transplant anesthesia programs meeting inclusion criteria were included. Results were categorized by their annual transplant volume.

RESULTS

A representative sample of 66% of all eligible centers contributed to the results. Normal saline among crystalloids and albumin among colloids were the most frequently chosen maintenance and non-blood product volume expansion fluids, with little variation by center size. A large variety of vasoactive agents is routinely utilized across programs, with vasopressors as a cornerstone of hemodynamic support. Large programs seem to use less of these agents compared with lower volume centers.

CONCLUSION

Anesthesiologists are increasingly involved in oversight and management of intraoperative renal replacement therapies, venovenous bypass and cell saver devices with rising transplant frequency. This new insight may be indicative of skill sets needed by members of liver transplantation anesthesia teams and should be considered in curriculum design for hepatobiliary transplant anesthesia fellowships.

The volume and pH of residual pharyngeal fluid aspirated from the TaperGuard Evac™ Endotracheal Tube following elective surgery: a prospective pilot study

BACKGROUND

Oropharyngeal suctioning prior to extubation aims to minimize postextubation tracheal soiling from remaining fluid. We investigated the amount and nature of any fluid remaining after such suctioning and contributing factors.

METHODS

ASA I - III patients undergoing elective surgery under general anesthesia with endotracheal intubation participated in this prospective observational pilot study. Following oropharyngeal suctioning immediately prior to extubation, a dedicated port of the endotracheal tube (TaperGuard Evac™ Endotracheal Tube) was aspirated. The amount and pH of residual fluid was recorded. Data collection included age, sex, body mass index, comorbidities, ASA status, procedure type and duration. The Chi-Square, Wilcoxon Rank-Sum, t-tests, and univariate regression analysis were used as appropriate.

RESULTS

Ninety-eight patients completed the study. The mean aspirated volume in 38 (38.8%) patients was 0.9 ± 1.3 mL and sixty patients (61.2%) had no aspirate. A body mass index of ≥ 30 kg/m2 was associated with the presence of fluid (P=0.03), and a higher volume (P=0.03). The fluid pH was 7 ± 0.81 (mean ± SD). A duration of surgery ≥ 120 minutes predicted a lower pH.

CONCLUSION

The prevalence and amount of residual fluid after oropharyngeal suctioning was low and likely clinically insignificant. A higher body mass index was associated with a higher incidence and volume of residual fluid. Longer procedure duration determined a slightly lower pH, with a mildly acidic pH range. The possibility of a lower fluid pH after prolonged surgery contributing to postoperative sore throat via mucosal irritation warrants investigation.

Single-dose intravenous paracetamol or propacetamol for prevention or treatment of postoperative pain: a systematic review and meta-analysis

Paracetamol is the most commonly prescribed analgesic for the treatment of acute pain. The efficacy and safety of i.v. formulations of paracetamol is unclear. We performed a systematic search (multiple databases, bibliographies, any language, to May 2010) for single-dose, randomized, controlled clinical trials of propacetamol or i.v. paracetamol for acute postoperative pain in adults or children. Thirty-six studies involving 3896 patients were included. For the primary outcome, 37% of patients (240/367) receiving propacetamol or i.v. paracetamol experienced at least 50% pain relief over 4 h compared with 16% (68/527) receiving placebo (number needed to treat=4.0; 95% confidence interval, 3.5-4.8). The proportion of patients in propacetamol or i.v. paracetamol groups experiencing at least 50% pain relief diminished over 6 h. Patients receiving propacetamol or paracetamol required 30% less opioid over 4 h and 16% less opioid over 6 h than those receiving placebo. However, this did not translate to a reduction in opioid-induced adverse events (AEs). Similar comparisons between propacetamol or i.v. paracetamol and active comparators were either not statistically significant, not clinically significant, or both. AEs occurred at similar rates with propacetamol or i.v. paracetamol and placebo. However, pain on infusion occurred more frequently in those receiving propacetamol compared with placebo (23% vs 1%). A single dose of either propacetamol or i.v. paracetamol provides around 4 h of effective analgesia for about 37% of patients with acute postoperative pain. Both formulations are associated with few AEs, although patients receiving propacetamol have a higher incidence of pain on infusion.

[Alkylphosphocholines inhibit lens epithelial cell proliferation and attachment]

BACKGROUND

Posterior capsule opacification (PCO) is one of the major concerns in modern cataract surgery. Ten years after successful surgery, Nd:YAG capsulotomy is required in up to 42% of patients with an acrylic sharp-edged intraocular lens (IOL). Some accommodative and multifocal IOLs display even higher capsulotomy rates. Pharmacologic prophylaxis with alkylphosphocholines (APCs) could be a novel option in PCO prevention.

METHODS

The human lens epithelial cell line HLE-B3 served as an in-vitro model. After incubation with APCs in different concentrations (0.01, 0.1, and 1 mM), the trypan blue exclusion assay and the live/dead test were performed at serum concentrations of only 5%. Cell proliferation was assessed with the MTT test. Evaluation of cell attachment was done with fibronectin- and laminin-coated wells.

RESULTS

APCs can inhibit the proliferation of human lens epithelial cells in the presence of only 5% serum in a dose-dependent manner. Proliferation inhibition of 60% and attachment inhibition of about 50% were reached at concentrations of 0.1 µM.

CONCLUSION

APCs inhibit proliferation and attachment of human lens epithelial cells in nontoxic concentrations in vitro. The substance can be applied topically, and an intraoperative application for pharmacologic PCO prophylaxis is feasible.

Prevention of biofilm growth on man-made surfaces: evaluation of antialgal activity of two biocides and photocatalytic nanoparticles

As algal growth on man-made surfaces impacts their appearance, biocides and surfaces with self-cleaning properties are widely used in the building and paint industries. The objective of this study was to evaluate the antialgal activity of two biocides (triazine and isothiazoline) and photocatalytic nanoparticles of zinc oxide (20-60 nm). An aeroterrestrial green, microalgal strain of the genus Stichococcus was chosen as the test organism. By comparing a set of different structural and physiological performance parameters, lethal and also sublethal (chronic) effects were determined. Even though the herbicide triazine effectively inhibited growth (EC50 = 1.6 micromol l(-1)) and photosynthetic performance, structural properties (eg membrane integrity) were unaffected at the EC100 (250 micromol l(-1)), hence this herbicide did not kill the algal cells. In contrast, and due to their multiple modes of action, isothiazoline and the photocatalytic nanoparticles (the latter activated with low UV radiation) severely impacted all performance and structural parameters.

Field methods for sampling and storing nectar from flowers with low nectar volumes

BACKGROUND AND AIMS

Although several methods of sampling and storing floral nectar are available, little information exists on sampling and storing nectar from flowers with low nectar volumes. Methods for sampling and storing nectar from the flowers of species with low floral nectar volumes (<1 microL) were investigated using the flowers of Eucalyptus species.

METHODS

Sampling with microcapillary tubes, blotting up with filter paper, washing and rinsing were compared to determine masses of sugars recovered and differences in sugar ratios. Storage methods included room temperature, refrigeration and freezing treatments; the addition of antimicrobial agents benzyl alcohol or methanol to some of these treatments was also evaluated. Nectar samples were analysed using high-performance liquid chromatography and the masses of sucrose, glucose and fructose in each sample were determined.

KEY RESULTS

Masses of sugars varied significantly among sampling treatments, but the highest yielding methods, rinsing and washing, were not significantly different. A washing time of 1 min was as effective as one of 20 min. Storage trials showed that the sugar concentration measurements of nectar solutions changed rapidly, with the best results achieved for refrigeration with no additive (sucrose and fructose were stable for at least 2 weeks). Sugar ratios, however, remained relatively stable in most treatments and did not change significantly across 4 weeks for the methanol plus refrigerator and freezing treatments, and 2 weeks for the refrigeration treatment with no additive.

CONCLUSIONS

Washing is recommended for nectar collection from flowers with low nectar volumes in the field (with the understanding that one wash underestimates the amounts of sugars present in a flower), as is immediate analysis of sugar mass. In view of the great variation in results depending on nectar collection and storage methods, caution should be exercised in their choice, and their accuracy should be evaluated. The use of pulsed amperometric detection, more specific than refractive index detection, may improve the accuracy of nectar sugar analysis.

Mu-opioid antagonists for opioid-induced bowel dysfunction

BACKGROUND

Opioid-induced bowel dysfunction (OBD) is characterized by constipation, incomplete evacuation, bloating, and increased gastric reflux. OBD occurs both acutely and chronically, in multiple disease states, resulting in increased morbidity and reduced quality of life.

OBJECTIVES

To compare the efficacy and safety of traditional and peripherally active opioid antagonists versus conventional interventions for OBD.

SEARCH STRATEGY

We searched MEDLINE, the Cochrane Central Register of Controlled Trials and EMBASE in January 2007. Additional reports were identified from the reference lists of retrieved papers.

SELECTION CRITERIA

Studies were included if they were randomized controlled trials that investigated the efficacy of mu-opioid antagonists for OBD.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent review authors and included demographic variables, diagnoses, interventions, efficacy, and adverse events.

MAIN RESULTS

Twenty-three studies met inclusion criteria and provided data on 2871 opioid antagonist-treated patients. The opioid antagonists investigated were alvimopan (nine studies), methylnaltrexone (six), naloxone (seven), and nalbuphine (one). Meta-analysis demonstrated that methylnaltrexone and alvimopan were better than placebo in reversing opioid-induced increased gastrointestinal transit time and constipation, and that alvimopan appears to be safe and efficacious in treating postoperative ileus. The incidence of adverse events with opioid antagonists was similar to placebo and generally reported as mild-to-moderate.

AUTHORS' CONCLUSIONS

Insufficient evidence exists for the safety or efficacy of naloxone or nalbuphine in the treatment of OBD. Long-term efficacy and safety of any of the opioid antagonists is unknown, as is the incidence or nature of rare adverse events. Alvimopan and methylnaltrexone both show promise in treating OBD, but further data will be required to fully assess their place in therapy.

The effects of ultraviolet radiation on photosynthetic performance, growth and sunscreen compounds in aeroterrestrial biofilm algae isolated from building facades

The effects of artificial ultraviolet radiation [UVR; 8 W m(-2) ultraviolet-A (UVA), 0.4 W m(-2) ultraviolet-B (UVB)] on photosynthetic performance, growth and the capability to synthesise mycosporine-like amino acids (MAAs) was investigated in the aeroterrestrial green algae Stichococcus sp. and Chlorella luteoviridis forming biofilms on building facades, and compared with the responses of two green algae, from soil (Myrmecia incisa) and brackish water (Desmodesmus subspicatus). All species exhibited decreasing quantum efficiency (Fv/Fm) after 1-3 days exposure to UVR. After 8-12 days treatment, however, all aeroterrestrial isolates exhibited full recovery under UVA and UVA/B. In contrast, D. subspicatus showed only 80% recovery after treatment with UVB. While Stichococcus sp. and C. luteoviridis exhibited a broad tolerance in growth under all radiation conditions tested, M. incisa showed a significant decrease in growth rate after exposure to UVA and UVA/B. Similarly D. subspicatus grew with a reduced rate under UVA, but UVA/B led to full inhibition. Using HPLC, an UV-absorbing MAA (324 nm-MAA) was identified in Stichococcus sp. and C. luteoviridis. While M. incisa contained a specific 322 nm-MAA, D. subspicatus lacked any trace of such compounds. UV-exposure experiments indicated that all MAA-containing species are capable of synthesizing and accumulating these compounds, thus supporting their function as an UV-sunscreen. All data well explain the conspicuous ecological success of aeroterrestrial green algae in biofilms on facades. Biosynthesis and accumulation of MAAs under UVR seem to result in a reduced UV-sensitivity of growth and photosynthesis, which consequently may enhance survival in the environmentally harsh habitat.

Aeroterrestrial microalgae growing in biofilms on facades--response to temperature and water stress

The photosynthetic performance of a microalgal biofilm colonizing a building facade was investigated between February and July 2004, with an emphasis on changing water availability and air humidity. The fluorimetric measurements of the quantum efficiency (F (v)/F (m)) indicated diurnal activity patterns. At most sampling dates the algal biofilm photosynthesized particularly in the morning and substantially less in the afternoon. As long as liquid water was present, the microalgae exhibited at least some degree of photosynthesis. However, F (v)/F (m) values never exceeded 0.4, pointing to slight photoinhibition or damage of the cells. Dried cells without photosynthesis could recover within minutes after artificial moistening. Three microalgal strains were isolated from aeroterrestrial biofilms and established as unialgal cultures. Their photosynthesis and growth were characterized under different air humidities and temperatures. Photosynthesis and growth of strain ROS 55/3 (Stichococcus sp.) showed similar patterns with decreasing relative air humidity. Positive growth and optimum photosynthesis were recorded at 100% relative air humidity. At air humidities below 93%, both processes were strongly inhibited. All studied strains grew between 1 and 30 degrees Celsius with optimum rates at 20-23 degrees Celsius, indicating eurythermal features. The data indicate that liquid water or 100% air humidity are the prerequisite for optimum photosynthesis and growth of aeroterrestrial microalgae. However, when dried and consequently inactive, these microorganisms can recover quickly if water is suddenly available, e.g., after rain events. These physiological capabilities explain well the ecological success of aeroterrestrial microalgae in occupying many man-made substrata such as building facades and roof tiles in urban areas.

Quantification of algal biofilms colonising building materials: chlorophyll a measured by PAM-fluorometry as a biomass parameter

The aim of this study was to quantify algal colonisation on anthropogenic surfaces (viz. building facades and roof tiles) using chlorophyll a (chl a) as a specific biomarker. Chl a was estimated as the initial fluorescence F0 of 'dark adapted' algae using a pulse-modulated fluorometer (PAM-2000). Four isolates of aeroterrestrial green algae and one aquatic isolate were included in this study. The chl a concentration and F0 showed an exponential relationship in the tested range between 0 and 400 mg chl a m(-2). The relationship was linear at chl a concentrations <20 mg m(-2). Exponential and linear models are presented for the single isolates with large coefficients of determination (exponential: r2 > 0.94, linear: r2 > 0.92). The specific power of this fluorometric method is the detection of initial algal colonisation on surfaces in thin or young biofilms down to 3.5 mg chl a m(-2), which corresponds to an abundances of the investigated isolates between 0.2 and 1.5 million cells cm(-2).

Bacterial abundance, activity, and viability in the eutrophic River Warnow, northeast Germany

The River Warnow is the drinking water source for the city of Rostock. Its eutrophic status is accompanied by high amounts of bacteria, which may reach up to 24 x 10(6) cells mL(-1) as recorded during a seasonal study in 2002. Because the river is eutrophic and also heavily loaded with organic matter, this burden is a problem for drinking water purification, as it must be removed completely to not trigger new bacterial growth in the pipeline network. Therefore, restoration measures in the river have to be planned, and bacteria have to be favored as decomposers. That includes the investigation of the physiological state of bacteria in situ. Viable and active cells in the lower reaches of River Warnow were estimated using a broad set of methods. Intact bacteria were investigated by the LIVE/DEAD BacLight bacterial viability kit, containing a mixture of permeant and impermeant nucleic acid stains. Cells with ribosomes were visualized by fluorescence in situ hybridization with the EUB338 oligonucleotide probe. Intact cells and ribosome-containing bacteria represented 24% of total numbers stained by 4'6,-diamidino-2-phenylindole (DAPI) or 66 and 62%, respectively, in relation to all bacteria visualized by the LIVE/DEAD kit. Both fractions were considered as viable, although the fraction of RIB + bacteria is most likely underestimated by the protocol applied. 5-Cyano-2,3-ditolyltetrazolium chloride (CTC) was applied to mark respiring bacteria. The esterase substrate CellTracker Green 5-chloromethylfluorescein diacetate showed cells with intracellular hydrolytic activity. Whereas 1.5% of DAPI-stained bacteria were observed as respiring, 3.8% exhibited intracellular hydrolytic activity on average. If these active fractions were calculated as the percentages of intact cells, much higher fractions of 5.4% were respiring and 16% hydrolytic. Temperature was a main factor influencing total and viable cell numbers simultaneously. The results confirm that there are different states of viable and active cells in natural bacterioplankton communities. However, it remains unclear why fractions of viable and active cells were rather low in this eutrophic river in comparison to similar waters. We recommend to carefully address cells as viable in contrast to nonviable, i.e., dead. As viable cells may be active or inactive with respect to many different activities, e.g., substrate uptake, respiration, hydrolysis, and cell deviation, it is necessary to choose the method to visualize active cells according to the question to be answered.

Population pharmacokinetics of methylprednisolone in accident victims with spinal cord injury

OBJECTIVE

High-dose methylprednisolone (MP) is used to treat acute spinal cord injury (ASCI). The objective of the present study was to determine the pharmacokinetics of the pro-drug methylprednisolone hemisuccinate (MPHS) and MP in accident victims with ASCI.

METHODS

The patients (n = 26) were treated with a bolus intravenous loading dose of 30 mg/kg MPHS within 2 h after injury and this was followed by a maintenance infusion of 5.4 mg/kg/h up to 24 h. Blood, CSF and saliva samples were collected up to 48 h after the initial dose and the samples were analyzed by HPLC. Concentration-time data of MPHS and MP were analyzed using population pharmacokinetic analysis with NONMEM software.

RESULTS

MPHS and MP could be monitored in plasma and CSF. MP but not MPHS was present in saliva. High variability was seen in the MPHS levels in CSF. The pharmacokinetics of the pro-drug and the metabolite were adequately described by a 2-compartment model with exponential distribution models assigned to the interindividual and the residual variability. At steady state, the average measured MP concentration in plasma was 12.3+/-7.0 microg/ml and 1.74+/-0.85 microg/ml in CSF. The CSF levels of MP could be modeled as a part of the peripheral compartment.

CONCLUSION

This study demonstrated that CSF concentrations of MP were sufficiently high after i.v. administration and reflected the concentrations of unbound drug in plasma. Salivary levels of MP were about 32% of the plasma level and may serve as an easily accessible body fluid for drug level monitoring.

[Laparoscopic therapy of appendicovesical fistula -- two case reports]

Two cases of appendicovesical fistula are reported. One case was caused by Crohn's disease, the second case by a chronical appendicitis. The guiding symptoms in both cases were coprosuria and pneumaturia, with chronical infection of the urinary tract. No diagnostic imaging method was able to detect the fistula. The correct diagnosis was finally made by laparoscopy followed by laparoscopical appendicectomy and fistula closure. The clinical symptoms alone seem to be sufficient for indication to operate. Thus, an early laparoscopic operation significantly can shorten the length of disease.

Connections, collisions, and complimentarity: the dynamic of health care chaplain, parish nurse and parish clergy collaboration

Parish nurses, health care chaplains, and community clergy can collaborate to create communities of wholeness. As these professionals extend their care and mission into the community, chaplains, parish nurses, and community clergy have opportunities for collaboration. These collaborative efforts come as a result of personal connections that can lead to collisions in priorities and philosophies but can also be productive complimentarity as they learn to work together for a common mission. Through connection this potential for collision or complimentarity, the community itself can participate with health professionals and clergy to help people be better, feel better, and carry suffering better.

Nifedipine block of capacitative calcium entry in cultured human uterine smooth-muscle cells

OBJECTIVE

To determine whether nifedipine inhibits capacitative calcium entry at clinically relevant concentrations using cultured human myocytes as a model for human myometrium.

METHODS

Myocyte cultures were initiated from the myometrium of term pregnant women who underwent cesarean delivery. Paired cells were chosen for study. The cell of interest was stimulated by an intercellular calcium wave from the adjacent cell. In this fashion, release of sarcoplasmic reticulum (SR) calcium was accomplished with minimal disturbance of the plasma membrane and the subplasmalemmal space (SPS) of the cell studied. Depletion of the SR calcium stores by the calcium wave activated the capacitative calcium current, elevated calcium in the SPS, and activated calcium-activated potassium channels. A cell-attached patch clamp was used to monitor the outward current resulting from the calcium activation of these potassium channels. Calcium green-1 fluorescence was used to simultaneously monitor changes of the deep cytosolic calcium concentrations. Experiments were performed at varying concentrations of nifedipine (0-10 micromol/L).

RESULTS

Nifedipine reduced outward potassium currents in a dose-dependent manner. Nifedipine at 100 nmol/L resulted in greater than a 50% reduction of outward current, indicating a significant inhibition of capacitative calcium entry at that concentration. Higher concentrations of nifedipine abolished outward current. Experiments designed to detect indirect effects of nifedipine on capacitative calcium entry were negative.

CONCLUSIONS

Nifedipine block of capacitative calcium entry occurred at concentrations similar to those required to block L-type voltage-activated calcium channels. These data suggest that block of capacitative calcium entry may be an important mechanism of action when nifedipine is clinically used for tocolysis of preterm labor.

Anterior window laryngoplasty: a new anatomic approach for posterior glottic and subglottic stensosis

This study explores the feasibility of an anterior thyroid window as a new approach for posterior glottic stenosis. An anterior window was made on the thyroid cartilage of human cadaver larynges, with its superior edge below the level of the vocal cords and an inferior pedicle composed of the inferior border of the thyroid cartilage attached to the cricothyroid membrane, which was left intact. By obtaining direct exposure of the posterior glottis and cricoarytenoid joints, mucosal graft suturing and exploration of the joints were easily achieved with an operating microscope. This study demonstrates the anatomic feasibility of an anterior window laryngoplasty as an alternative approach to treating posterior glottic stenosis while preserving the cartilage framework and avoiding the anterior commissure. This technique may improve endolaryngeal manipulation by providing a closer and more direct exposure than do endoscopic techniques, and by having fewer possible complications than traditional open techniques.

Intracellular calcium gradients in cultured human uterine smooth muscle: a functionally important subplasmalemmal space

The plasma membrane contains the key elements for the control of coupling excitation to contraction in smooth muscle. The superficial calcium buffer barrier, initially proposed by van Breemen for vascular smooth muscle, may participate in the regulation of calcium entry in other smooth muscle types. To investigate the relationship between the sarcoplasmic reticulum (SR) and the plasma membrane in myometrial smooth muscle cells, we performed experiments using videofluorescence imaging and cell-attached electrophysiology. The cell-attached patch was used as a reporter for the free calcium in the subplasmalemmal space by monitoring openings of the Maxi-K channel. Calcium green-1 was used to simultaneously monitor changes of the deep cytosolic calcium concentrations. The cell with the patch attached was stimulated via an intercellular calcium wave from an adjacent cell. In this fashion, release of SR calcium was accomplished with minimal disturbance of the plasma membrane and the subplasmalemmal space of the cell studied. With physiological bathing solution, six of seven calcium waves activated Maxi-K channels. Surprisingly, the Maxi-K channels began opening 6.3 +/- 4.7s (range 2.6-15.0s) after the wave passed the pipette location. When plasma membrane calcium fluxes were inhibited with 100 microM lanthanum, no Maxi-K channel openings were observed in six of seven experiments. These results are best explained by a subplasmalemmal space in which the calcium concentration is largely controlled by store-operated channels. These results suggest the superficial buffer barrier as merely one aspect of subplasmalemmal regulation of calcium dynamics, and emphasize the importance of store-operated calcium channels during dynamic calcium changes.

Effects of remifentanil on neutrophil adhesion, transmigration, and intercellular adhesion molecule expression

BACKGROUND

Anaesthetic drugs are used for pain therapy and anaesthesia. Neutrophils play a significant role during the process of inflammation. The aim of the current study was to investigate the effects of remifentanil and fentanyl on neutrophil migration through endothelial cell monolayers, and on adhesion molecule expression.

METHODS

After isolation of polymorphonuclear neutrophils (PMNL) we used a currently described migration assay. PMNL and/or endothelial cell monolayers (ECM) were pre-treated with remifentanil using clinically relevant, as well as higher and lower concentrations or relevant concentrations of fentanyl.

RESULTS

Concentrations of remifentanil (50 ng/mL) similar to the relevant plasma concentration were able to inhibit PMNL migration through ECM significantly (migration compared to the control 82+/-7% SD; P<0.05), when both cell types were treated with the synthetic narcotic remifentanil. Fentanyl (30 ng/mL) showed a stronger inhibitory effect (migration compared to the control 67+/-9.2%; P<0.05). Endothelial cell adhesion molecule expression was reduced after either remifentanil or fentanyl.

CONCLUSION

The results of the present investigation indicate that remifentanil influences interaction of ECM against human neutrophils. Compared to fentanyl, remifentanil seems to exhibit minor inhibitory effects on neutrophil migration.

The effect of electrostatic charge of food particles on capture efficiency by Oxyrrhis marina Dujardin (dinoflagellate)

Laboratory experiments were carried out to investigate the effect of food quality, measured as surface charge of the particles, on capture efficiency and ingestion rate by the heterotrophic dinoflagellate Oxyrrhis marina. Fluorescent particles in two size classes of around 1 and 4 microm and of 7 different qualities were offered to the flagellate: carbohydrate and albumin particles, the algae Synechocystis spec. and Chlorella spec., carboxylated microspheres, silicate particles and bacteria. Rates of particle uptake showed significant differences depending on particle size and quality, and ranged from 0 to 4 particles cell(-1) h(-1). Ingestion rates were up to 4 times higher for 4 pm particles than for 1 microm particles, which indicates strong size-selective feeding. Our main result is that the surface charge or zeta potential, of artificial particles, i.e. carboxylated microspheres (> or = -107 mV) and silicate particles, strongly differ from more natural and natural food (< or = -17 mV). For both size classes Oxyrrhis had ingestion rates up to 4 times higher for particles with less negative charge, such as albumin particles or algae. Thus, the zeta potential of the model food should be considered in experimental design. Particles with a zeta potential similar to that of natural food, e.g. albumin, seem to be the preferred model food.

Maintaining squamous epithelial architecture in a human cervical epithelium to SCID mouse xenograft model system

OBJECTIVE

To establish a mouse model system of human cervical epithelium that maintains the stratified squamous architecture overlying a well-defined basement membrane.

METHODS

Normal cervical tissue specimens were obtained from the transformation zone of hysterectomy specimens. Small (2 mm) cubes of tissue containing stroma and epithelium were placed subdermally into severe combined immunodeficient (SCID) mice and harvested between 7 and 45 days. Specimens were examined histologically for the presence of stroma, epithelium, and basement membrane.

RESULTS

In 49 xenograft attempts in 24 mice, 35 (71%) were identified microscopically. Of these, 28 (80%) had identifiable epithelium and 20 (57%) formed cysts lined with stratified squamous epithelium. A cuboidal basal layer clearly defined the basement membrane. Proliferation within the cyst epithelium was demonstrated by expression of the Ki67 proliferation marker and the presence of mitotic figures.

CONCLUSIONS

A human to mouse xenograft model system is described that maintains, in high yield, stratified squamous epithelium overlying a well-defined basement membrane. Advantages of this model system include the following: (1) The tissue originates from readily available human specimens; (2) A stratified squamous epithelial architecture is maintained for a sufficient time to study viral effects on proliferation; (3) The basement membrane of the epithelium is well defined, allowing for investigation of connective tissue factors in cervical intraepithelial neoplasia and cervical cancer.

Acute transjugular intrahepatic portosystemic shunt migration into pulmonary artery during liver transplantation

Transjugular intrahepatic portosystemic shunt has become an accepted intervention to treat sequelae of end-stage liver disease such as refractory ascites and esophageal varices for patients awaiting liver transplantation. Technical difficulties in such patients at the time of transplantation are usually limited to malpositioning of the stent requiring modification of the usual vascular anastomoses. Migration of the stent intraoperatively has not been a reported complication in the literature. We report a case in which a patient with a previously placed transjugular intrahepatic portosystemic shunt underwent successful liver transplantation complicated by intraoperative migration of the stent into the left pulmonary artery. The stent was removed from the pulmonary artery postoperatively using interventional radiology techniques.

Determination of geosmin and 2-methylisoborneol in water using solid-phase microextraction and gas chromatography-chemical ionisation/electron impact ionisation-ion-trap mass spectrometry

A method for the determination of geosmin and 2-methylisoborneol (MIB) in water by solid-phase microextraction (SPME) is presented. Various SPME fibre chemistries have been compared for their efficiency in extracting MIB from water. Extraction conditions including the extraction time and temperature have been optimised. A 30 ml water sample is extracted for 20 min at 60 degrees C using a divinylbenzene fibre, and the extract analysed by gas chromatography with ion-trap mass spectrometry detection. d5-Geosmin and d3-MIB are added as internal standards to compensate for any variability in the SPME process which is not carried out to equilibrium. Chemical ionisation, using acetonitrile as the reagent gas, was found to give superior sensitivity to electron impact ionisation (EI) for the detection of MIB. EI was used as the ionisation mode for detection of geosmin. The method shows good linearity over the concentration range 5-40 ng l-1 and gives detection limits of 1 ng l-1 for both geosmin and MIB. Recovery (93-110%) and precision (3-12%) over this concentration range, for both raw and treated drinking waters, are comparable to currently employed methods such as closed-loop stripping analysis (CLSA). The method offers the advantage of being simple to use, with much shorter analysis times in comparison to CLSA.

Inflammation in high-grade carotid stenosis: a possible role for macrophages and T cells in plaque destabilization

BACKGROUND AND PURPOSE

Inflammatory mechanisms have been implicated in the pathogenesis of atherosclerosis. In this study, we investigated whether the extent of inflammatory infiltration in high-grade stenoses of the internal carotid artery (ICA) correlates to clinical features of plaque destabilization.

METHODS

Endarterectomy specimens from 37 consecutive patients undergoing surgery for high-grade ICA stenosis were stained immunocytochemically for macrophages (CD68) and T cells (CD3). The staining was quantified by planimetry of immunostained areas (CD68) or counting individual cells (CD3). Clinical evidence of plaque instability was provided by the preoperative assessment of recent ischemic symptoms attributable to the stenosis and of the occurrence of cerebral microembolism in transcranial Doppler ultrasound monitoring of the ipsilateral middle cerebral artery.

RESULTS

The percentage of macrophage-rich areas and number of T cells per mm2 section area were larger in recently symptomatic patients than in asymptomatic patients (macrophages: 18+/-10% versus 11+/-4%, P=0.005; T cells: 71.2+/-34.4 versus 40.5+/-31.4 mm2, P=0.005). The presence of microembolism was associated with an increase in macrophage-rich areas (P=0.011). Macrophage (19+/-10% versus 9+/-3%, P=0.0009) and T cell (71.5+/-39.0 versus 46.4+/-22 mm2, P=0.045) infiltration were more pronounced in predominantly atheromatous than in fibrous plaques, but did not correlate significantly to the presence of surface ulceration or luminal thrombosis.

CONCLUSIONS

Our data suggest a role of plaque-infiltrating macrophages and T cells in the clinical destabilization of high-grade ICA stenoses. Inflammatory mechanisms may be a therapeutic target in patients with symptomatic ICA disease.