Quantifying single-cell diacylglycerol signaling kinetics after uncaging.

Studying the role of molecularly distinct lipid species in cell signaling remains challenging due to a scarcity of methods for performing quantitative lipid biochemistry in living cells. We have recently used lipid uncaging to quantify lipid-protein affinities and rates of lipid trans-bilayer movement and turnover in the diacylglycerol signaling pathway. This approach is based on acquiring live-cell dose-response curves requiring light dose titrations and experimental determination of uncaging photoreaction efficiency. We here aimed to develop a methodological approach that allows us to retrieve quantitative kinetic data from uncaging experiments that 1) require only typically available datasets without the need for specialized additional constraints and 2) should in principle be applicable to other types of photoactivation experiments. Our new analysis framework allows us to identify model parameters such as diacylglycerol-protein affinities and trans-bilayer movement rates, together with initial uncaged diacylglycerol levels, using noisy single-cell data for a broad variety of structurally different diacylglycerol species. We find that lipid unsaturation degree and side-chain length generally correlate with faster lipid trans-bilayer movement and turnover and also affect lipid-protein affinities. In summary, our work demonstrates how rate parameters and lipid-protein affinities can be quantified from single-cell signaling trajectories with sufficient sensitivity to resolve the subtle kinetic differences caused by the chemical diversity of cellular signaling lipid pools.

Expanding the role of mammographers: a training strategy to enhance mammographer-patient interaction.

The use of routine mammography screening is associated with earlier breast cancer detection and decreased mortality. Several researchers have identified mammographers as potentially effective agents for encouraging patients to engage in routine screening. Mammographers are particularly well situated within the health care system to address patients' knowledge, psychological, and cultural barriers to routine screening. Few opportunities exist, however, for mammographers to acquire skills in providing culturally-sensitive patient education and emotional assessment to help women overcome such barriers. In 1997 the North Carolina Breast Cancer Screening Program (NC-BCSP) developed and implemented an innovative, two-hour training program to help mammographers address the educational and psychosocial needs of rural, African American women in eastern North Carolina. NC-BCSP's extensive survey data (n=2000), as well as qualitative data from 25 focus groups conducted with more than 200 rural African American women, were used to develop a curriculum titled Expanding the Role of Mammographers. It was the first American Society of Radiologic Technologists (ASRT) accredited training program for mammographers in North Carolina that solely addressed psychosocial topics. The curriculum emphasized mammographers' potential impact on women's attitudes and behavioral intentions, and taught communication strategies to enhance mammographer-patient interaction. It included supplemental learning materials, skill-building exercises, and patient education materials to assist participants in applying new skills and knowledge. Of the 33 mammographers invited to the training, 19 attended. A structured evaluation form, completed by 18 participants, conveyed positive reactions to the intervention. This training workshop was conducted as part of NC-BCSP's much larger, community-based intervention; as such, it was not independently evaluated. NC-BCSP's broader intervention appears to be associated, however, with positive population-level changes in breast cancer awareness and mammography use.

ARDS in fulminant ornithosis and treatment with extracorporeal lung assist.

We report a 47-year-old male patient with fulminant ornithosis who developed severe respiratory failure leading to acute respiratory distress syndrome (ARDS) complicated by gastrointestinal, neurological and renal symptoms. ARDS was successfully treated by extracorporeal lung assist. As leukocytosis is typically absent in ornithosis, C-reactive protein, interleukin 6 and procalcitonin were used as infection parameters in order to monitor clinical development. The English-language literature on severe cases of ornithosis requiring respiratory support over the past 30 years is reviewed.

[Intra- and postoperative airway management of tracheal carina ruptures from bilateral endobronchial intubation]. / Intra- und postoperatives Airway-Management karinanaher Trachealrupturen über bilaterale endobronchiale Intubation.

OBJECTIVE: Carina near tracheal ruptures following blunt chest trauma or endotracheal intubation are rare, but lifethreatening events. Both early diagnosis by fibreoptic bronchoscopy and immediate surgical treatment are essential. There is no uniform recommendation for airway-management concerning the tube. Standard tracheal- and double-lumen tubes position the cuff at the site of the injury and tracheostomy tubes are too short to protect the lesion from positive airway pressure. We discuss the causes, diagnosis, and treatment of tracheal ruptures, reviewing the recent literature. METHODS: We analysed data from three female patients who sustained carina near tracheal ruptures. They underwent selective endobronchial intubation with two tubes, both under fibreoptic control. Following the surgical repair the tubes were then introduced via tracheostomy. Because of severe respiratory failure (aspiration pneumonia, mediastinitis, status asthmaicus, ARDS) independent lung ventilation was performed for 9-14 days. Obviously the fixation of the tubes is most essential and their correct position was confirmed by daily fibreoptic or radiologic control. Then a single tracheostomy tube was inserted. RESULTS: The patients respiratory functions improved and they were discharged from ICU after 21-36 days, breathing spontaneously with closed tracheostoma. No long-term complications were noted. CONCLUSION: Maintaining the safety procedures the bilateral endobronchial intubation is an important and successful method in carina near tracheal rupture, perioperatively and for long-term ventilation.

[Rett's syndrome: pathophysiology and anesthesiological implications]. / Das Rett-Syndrom: Pathophysiologie und anästhesiologische Implikationen, dargestellt anhand eines Fallbeispiels.

Rett's syndrome is a neurodevelopmental disorder which is caused by a mutation on the x-chromosome; thus, it only affects the female sex. After seemingly normal postnatal development affected girls lose already acquired mental, motoric and social skills. The last stage of the syndrome is characterized by microcephaly, severe mental retardation, spastic paraparesis, epilepsia, respiratory dysrhythmia, neurogenic scoliosis, abnormal joint alignment and muscle contractures. Rett's syndrome is probably the leading cause for progressive mental retardation in girls, but still it is relatively unknown. This paper describes Rett syndrome and its pathophysiology. The following case report discusses special anesthesiological implications due to the immature cardiorespiratory system and describes a coagulation disorder following treatment with valproic acid.

[Blood gas analysis in interhospital transfer--a useful extension of respiratory monitoring?]. / Blutgasanalyse im Interhospitaltransfer--eine sinnvolle Ergänzung des respiratorischen Monitorings?

OBJECTIVE: Investigation of blood gas analysis during hospital-to-hospital transport of ventilated ICU-patients to detect critical events, changes of gas exchange and reliability of non-invasive monitoring. METHODS: 47 ventilated patients (age 9-76 years, mean 50 years, diagnosis: ARDS = 16, intracranial bleeding = 14, severe trauma = 4, acute hemodynamic failure = 3, others = 10), transported by a special physician staffed intensive care ambulance using invasive hemodynamic monitoring. Blood gas analysis was performed before and during transport every 30 minutes and respirator mode, vital signs and events were documented. RESULTS: In 19 (40.4%) patients there were critical events during transport (paO2 < 70 mmHg, paCO2 < 25 mmHg, paCO2 > 55 mmHg, pH < 7.30, pH > 7.55). In 4 patients with PaO2 < 70 mmHg there was SpO2 > or = 97% (by pulsoximetry), correlation between SaO2 (invasive) and SpO2 (by pulsoximetry) was r = 0.81 (P < 0.001) with a maximum difference of 8 percent. In several patients critical changes of condition could be recognized in an early stage by blood gas analysis. CONCLUSIONS: Blood gas analysis during hospital-to-hospital transport of ICU-patients can be performed easily and allows to optimize artificial ventilation and to recognize earlier and safer severe problems of gas exchange.

Elimination of drugs by the new polyamide hemofilter FH77H during various in vitro conditions.

BACKGROUND/AIMS: Multiple organ failure alters the dosage of drugs during hemofiltration. To separate factors, we utilized in vitro hemofiltration to investigate different blood flows, protein concentrations and intracellular drug partition with the FH77H polyamide membrane. METHODS: One liter of warm heparinized fresh human blood was hemofiltrated in two series: (1) with digoxin, netilmycin, phenobarbital, ceftriaxone and teicoplanin, and (2) with amikacin, theophylline, ceftazidim, phenytoin and vancomycin and, in addition, with cell-free fresh frozen plasma. RESULTS: The increased volumes of distribution of aminoglycosides and theophylline were a combined result of partition into cells and adsorption into the filter membrane. The deviations of drug sieving from predicted values were due to different affinities of the drugs on whole blood binding sites. CONCLUSION: The in vitro composition of drugs and blood improved the detection of factors that influence drug elimination during hemofiltration. The FH77H polyamide hemofilter facilitates more precise predictions of drug dosages by low adsorption rates to the membrane.

Pharmacokinetics of ceftriaxone in patients undergoing continuous veno-venous hemofiltration.

Continuous hemofiltration is used widely in the management of patients with acute renal failure, but administration guidelines for many drugs have yet to be established. In this study, the pharmacokinetics of ceftriaxone were compared in patients with normal renal function (n = 9), mild renal insufficiency (n = 5), and acute renal failure receiving continuous veno-venous hemofiltration (n = 6). Pharmacokinetic parameters were determined under steady state conditions. Patients with mild renal insufficiency had a significantly lower renal clearance and longer half-life of ceftriaxone; however, drug recovery in the ultrafiltrate with continuous veno-venous hemofiltration was similar to that in the urine of patients with normal renal function. Pharmacokinetic parameters for renal, nonrenal, and systemic clearance and for volume of distribution and half-life were also similar between patients receiving continuous veno-venous hemofiltration and those with normal renal function. The sieving coefficient (S) of ceftriaxone (0.69) significantly exceeded the expected free fraction in plasma, confirming previous reports that protein binding does not limit the sieving of this compound. The results suggest that a reduction in the usual daily dose of ceftriaxone is not required in patients with acute renal failure receiving continuous veno-venous hemofiltration.

[Can preoperative lung function diagnosis detect risk of intraoperative pulmonary gas exchange insufficiency in artificial hip replacement with polymethylmethacrylate cement?]. / Lässt die präoperative Lungenfunktionsdiagnostik das Risiko intraoperativer pulmonaler Gasaustauschstörungen in der Hüftendoprothetik mit Polymethylmetacrylat-Zement erkennen?

In a study of 90 patients in whom a hipjoint had been replaced for the first time using polymethylmetacrylate cement, the extent of intraoperative pulmonary gas exchange disorders was established. The effect of a preexisting disorder of lung function was determined. We checked whether an appraisal of the risk patients who are operated on can be assisted by a preoperative analysis of lung function. After preoperative diagnosis of lung function, the arterial blood gases were analysed at defined times during the operation. An intraoperative fall in the partial pressure of oxygen and an increase in carbon dioxide partial pressure in the arterial blood were found in all patients. There were pronounced interindividual differences in the extent of the disorder of pulmonary gas exchange. The degree of severity of the respective acute disorder of lung function did not show any correlation with the pre-existing disorder of pulmonary ventilation. Major hemodynamic changes were not observed. According to the present findings, a definitive statement with regard to the degree of severity of intraoperatively occurring disorders of pulmonary function cannot be expected from a preoperative analysis of pulmonary function.

[Treatment of acute pulmonary infection in a mucoviscidosis patient with extracorporeal lung support]. / Behandlung eines akuten pulmonalen Infektes bei einem Mukoviszidose-Patienten mittels extrakorporaler Lungenunterstützung.

This is a report on a mucoviscidosis patient of 30 years of age suffering from refractory acute failure of pulmonary function during acute exacerbation of an infection with Pseudomonas aeruginosa. To avoid further barotraumatisation of the lungs due to continually increasing artificial respiratory pressure, and to set the lung at rest until subsidence of a concomitant severe bronchial obstruction, we performed modified extracorporal lung assist (ELA). The gas exchange improved rapidly with the help of relevant accompanying measures (including negative liquid balance, administration of antibiotics, etc.) and the pulmonary infection also subsided to a major extent. 26 days after the end of the bypass the patient could be transferred for lung transplantation.

Progress in veno-venous long-term bypass techniques for the treatment of ARDS. Controlled clinical trial with the heparin-coated bypass circuit.

Extracorporeal CO2 removal combined with low-frequency positive pressure ventilation (ECCO2-R LFPPV) is a new therapeutic approach in treatment of ARDS. The main problem during long-term extracorporeal support is anticoagulation and related bleeding problems. We conducted a prospective, randomized and controlled clinical trial in 18 patients to compare the effect of the non-heparin-coated (Scimed = group 1) with the heparin-coated (Carmeda = group 2) extracorporeal circuit on clinical course and complication rate. In group 2 the daily blood loss, the amount of substituted red cells and the i.v. heparin dose were significantly lower than in group 1. Bleeding complications were less and more patients survived in group 2. The disadvantage of the hollow fiber oxygenators in the heparin-coated system was plasma leakage, which was more frequent in patients with pancreatitis and hyperbilirubinemia.

Evaluation and first validation study on a simplified drug dosage algorithm for multiple organ failure patients.

As reported previously, drug concentrations during continuous hemofiltration (HF) and extracorporeal lung assist (ELA) follow certain rules, which can be expressed by a simplified algorithm for dosage adjustment: Drug sieving (S, fu) depends on the protein free fraction with small limitations, while the extrarenal elimination rate is not a constant but correlates inversely with the clinical state, r = -0.34, p = 0.00067, n = 96. Up to now, more than 218 cases of drug dosage adjustments have been performed, following the described regimen: The expected concentration is obtained in 79-84% already from the first estimation for drugs such as aminoglycosides, vancomycin, teicoplanin, beta-lactam antibiotics, heart glycosides, and theophylline. Skilled therapeutic drug monitoring (TDM) with elaborated pharmacokinetic programs fails to improve these results significantly. Nevertheless, sporadic TDM is essential in these patients according to their rapidly changing clinical states.

The prognostic value of extracellular matrix component concentrations in serum during treatment of adult respiratory distress syndrome with extracorporeal CO2 removal.

The time-dependent concentrations of hyaluronan, aminoterminal propeptide of type III procollagen, and laminin were determined in sera of 16 patients with severe adult respiratory distress syndrome during treatment with an extracorporeal CO2 removal device. Patients were classified according to lung parameters as responders (n = 10) and non-responders (n = 6) to extracorporeal CO2 removal. At the beginning of treatment strongly elevated serum concentrations of all studied extracellular matrix components were found. During the first 6-11 days of treatment the concentrations of aminoterminal propeptide of type III procollagen and hyaluronan increased further in non-responders but decreased in the majority of responders, while laminin decreased in both groups. No significant correlations were found between the serum concentrations of connective tissue components and the parameters of lung function. By non-parametric analysis of variance, significant differences between responders and non-responders according to treatment time could be established. By analysing the time course of the serum concentrations of hyaluronan and aminoterminal propeptide of type III procollagen, a total differentiation between responders and nonresponders was made possible by the trends of these analytes as early as three days after the start of treatment. The determination of aminoterminal propeptide of type III procollagen and hyaluronan in serum of patients with adult respiratory distress syndrome might therefore have prognostic significance in extracorporeal CO2 removal.

[Determinations by indirect calorimetry need not be expensive and technically complicated. A new measurement system and its validation]. / Die Bestimmung der indirekten Kalorimetrie muss nicht teuer und technisch aufwendig sein. Ein neues Messsystem und seine Validierung.

Presentation of a newly conceived measuring instrument to determine the energy expenditure of critically ill patients at the bedside by means of indirect calorimetry. The special advantages of the measuring instruments are easy handling, little maintenance and very low working expenses and prime costs. The accuracy of measurement is considerable nd is comparable with that of other measuring methods, as has been established by an extensive validation.

[The importance of Pneumocystis carinii infection in patients with acute respiratory distress syndrome]. / Die Bedeutung der Pneumocystis-carinii-Infektion bei Patienten mit akutem Lungenversagen.

Each year we treated approximately 40 patients with adult respiratory distress syndrome (ARDS) in our department of anaesthesiology. In these cases we found with bronchoalveolar lavage followed by microbiological examination, a high incidence (40 per cent) of pneumocystis carinii contamination. An infection with Pneumocystis carinii deteriorates the clinical course of ARDS. Effective drugs were the combination of trimethoprim and sulfamethoxazole. Under this therapy we always saw a decrease of infiltrations in the chest-x-ray as well as an improved gas exchange. No relapse was seen in any case.

[Drugs in the intensive care unit--need for dosage adjustment in organ failure]. / Arzneimittel auf der Intensivstation--Notwendigkeit der Dosisanpassung bei Organversagen.

Drug dosage in intensive care patients is a common problem that cannot be sufficiently solved in practice. To obtain an idea as to the variance of multiorgan failure during treatment, the pharmacokinetics of 17 drugs were evaluated in 96 patients. Continuous hemofiltration served as a model for constant elimination rates. In addition, the elimination of drugs was investigated during extracorporeal lung support. For 11 of 15 drugs on which kinetic studies had been completed, dose reductions had to be performed. Furthermore, widespread variance in their volume of distribution and their clearance and in the extrarenal fraction of elimination were detected. The latter showed a close correlation to clinical scores of illness. This led us to develop a new algorithm for primary estimations of drug dosage during hemofiltration. In a preliminary validation study, the algorithm seemed to show an improvement in the drug dosage in these populations. Nevertheless, a more simplified means of monitoring therapeutic drugs should be continued, especially for toxic agents.

[Infection-induced change in the pharmacokinetics of cefotaxime. Dose calculation in multiple organ failure and relevance of score systems]. / Sepsisbedingte Anderung der Pharmakokinetik von Cefotaxim. Dosiskalkulation im Multiorganversagen und Relevanz von Scoresystemen.

The pharmacokinetics of cefotaxime were investigated in 14 patients suffering from multiple-organ failure requiring pump-assisted, continuous volume-constant hemofiltration (CVHF) for blood purification, whereby the filtration rate was 20 ml/min. Samples of blood and ultrafiltrate were evaluated by high-pressure liquid chromatography. For dose adjustment, three different algorithms of Dettli and Kroh were used. As compared with values obtained for anuric patients during the dialysis-free period, the mean serum half-life was nearly doubled (2.75 vs 4.48 h). This reduced elimination depended mainly on a diminished non-renal elimination ratio ranging from 0.085 to 0.366. The volume of distribution remained unchanged within a wide interindividual range (Vz, 0.35 l/kg, from 0.22 to 0.56 l/kg); the sieving coefficient increased to 0.89 as compared with 0.62 in healthy volunteers. Dose adjustment by algorithms showed varied degrees of over-dosage. The estimate closest to an optimal dose was reached by the application of a new algorithm of Kroh (mean dose deviation +19%; SD, +/- 27%) using an individual non-renal elimination ratio (QIND). QIND correlated significantly with the severity of disease according to the sepsis score of Elebute and Stoner (r = 0.763, P less than 0.005). Thus, it is possible to adjust reliably individual dosage in multiple-organ failure and to reduce the frequency of drug monitoring required.