[New antibiotics for severe infections due to multidrug-resistant pathogens : Definitive treatment and escalation]

Multidrug-resistant pathogens often lead to treatment failure of antimicrobial regimens. After a period of imbalance between the occurrence/spread of resistance mechanisms and the development of new substances, some new substances have meanwhile been approved and many more are currently undergoing clinical testing. They are particularly effective against specific resistance mechanisms/pathogens and should be preserved for definitive treatment of an isolated pathogen. In the absence of alternatives reserve antibiotics, such as aztreonam and colistin have experienced a renaissance. They are again used in special infection scenarios and clinically tested in combination with new substances. Despite the introduction and development of new substances the building of resistance will at some time also render these (at least partially) ineffective. Therefore, their implementation must be carried out according to the antibiotic or infectious diseases stewardship.

[S2k guidelines of the PEG on calculated parenteral initial treatment of bacterial diseases in adults : Focussed summary and supplementary information on antibiotic treatment of critically ill patients]

In January 2018 the recent revision of the S2k guidelines on calculated parenteral initial treatment of bacterial diseases in adults-update 2018 (Editor: Paul Ehrlich Society for Chemotherapy, PEG) was realized. It is a helpful tool for the complex infectious disease setting in an intensive care unit. The present summary of the guidelines focuses on the topics of anti-infective agents, including new substances, pharmacokinetics and pharmacodynamics as well as on microbiology, resistance development and recommendations for calculated drug therapy in septic patients. As in past revisions the recent resistance situation and results of new clinical studies are considered and anti-infective agents are summarized in a table.

[Adequate anti-infective treatment : Importance of individual dosing and application]

Sepsis-induced changes in pharmacokinetic parameters are a well-known problem in intensive care medicine. Dosing of antibiotics in this setting is therefore challenging. Alterations to the substance-specific kinetics of anti-infective substances have an effect on the distribution and excretion processes in the body. Increased clearance and an increased distribution volume (V_d) and particularly compromized organ function with reduced antibiotic elimination are often encountered in patients with sepsis. Renal replacement treatment, which is frequently used in intensive care medicine, represents a substantial intervention in this system. Current international guidelines recommend individualized dosing strategies and adaptation of doses according to measured serum levels and pharmacokinetic/pharmacodynamic (PK/PD) parameters as concepts to optimize anti-infective therapy in the critically ill. Likewise, the recommendation to adjust the administration form of beta-lactam antibiotics to prolonged or continuous infusion can be found increasingly more often in the literature. This article reviews the background of the individual dosing in intensive care patients and their applicability to the clinical routine.

[Bacterial sepsis : Diagnostics and calculated antibiotic therapy]

The mortality of patients with sepsis and septic shock is still unacceptably high. An effective antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed focus and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account for selection of anti-infection treatment. Many pathophysiological alterations influence the pharmacokinetics of antibiotics during sepsis. The principle of standard dosing should be abandoned and replaced by an individual treatment approach with stronger weighting of the pharmacokinetics/pharmacodynamics (PK/PD) index of the substance groups. Although this is not yet the clinical standard, prolonged (or continuous) infusion of beta-lactam antibiotics and therapeutic drug monitoring (TDM) can help to achieve defined PK targets. Prolonged infusion is sufficient without TDM but for continuous infusion TDM is basically necessary. A further argument for individual PK/PD-oriented antibiotic approaches is the increasing number of infections due to multidrug resistant pathogens (MDR) in the intensive care unit. For effective treatment antibiotic stewardship teams (ABS team) are becoming more established. Interdisciplinary cooperation of the ABS team with infectiologists, microbiologists and clinical pharmacists leads not only to a rational administration of antibiotics but also has a positive influence on the outcome. The gold standards for pathogen detection are still culture-based detection and microbiological resistance testing for the various antibiotic groups. Despite the rapid investigation time, novel polymerase chain reaction (PCR)-based procedures for pathogen identification and resistance determination, are currently only an adjunct to routine sepsis diagnostics due to the limited number of studies, high costs and limited availability. In complicated septic courses with multiple anti-infective treatment or recurrent sepsis, PCR-based procedures can be used in addition to therapy monitoring and diagnostics. Novel antibiotics represent potent alternatives in the treatment of MDR infections. Due to the often defined spectrum of pathogens and the practically absent resistance, they are suitable for targeted treatment of severe MDR infections (therapy escalation).

Drag-reducing riblets with fouling-release properties: development and testing

The manufacture and preliminary testing of a drag-reducing riblet texture with fouling-control properties is presented. The commercial fouling-release product Intersleek® 1100SR was modified to manufacture riblet-textured coatings with an embossing technology. Hydrodynamic drag measurements in a Taylor-Couette set-up showed that the modified Intersleek® riblets reduced drag by up to 6% compared to a smooth surface. Barnacle settlement assays demonstrated that the riblets did not substantially reduce the ability of Intersleek® 1100SR to prevent fouling by cyprids of Balanus amphitrite. Diatom adhesion tests revealed significantly higher diatom attachment on the riblet surface compared to smooth Intersleek® 1100SR. However, after exposure to flow, the final cell density was similar to the smooth surface. Statically immersed panels in natural seawater showed an increase of biofilm cover due to the riblets. However, the release of semi-natural biofilms grown in a multi-species biofilm culturing reactor was largely unaffected by the presence of a riblet texture.

[Therapeutic drug monitoring and individual dosing of antibiotics during sepsis : Modern or just "trendy"?]

Pharmacokinetic variability of anti-infective drugs due to pathophysiological changes by severe sepsis and septic shock is a well-known problem for critically ill patients resulting in suboptimal serum and most likely tissue concentrations of these agents.To cover a wide range of potential pathogens, high concentrations of broad spectrum anti-infectives have to reach the site of infection. Microbiological susceptibility testing (susceptible, intermediate, resistant) don't take the pharmacokinetic variability into account and are based on data generated by non-critically ill patients. But inter-patient variability in distribution and elimination of anti-infective drugs in ICU patients is extremely high and also highly unpredictable. Drug clearance of mainly renally eliminated drugs and thus the required dose can differ up to 10-fold due to the variability in renal function in patients with severe infections. To assure a timely and adequate anti-infective regime, individual dosing and therapeutic drug monitoring (TDM) seem to be appropriate tools in the setting of pathophysiological changes in pharmacokinetics (PK) and pharmakodynamics (PD) due to severe sepsis. In the case of known minimal inhibitory concentration, PK/PD indices (time or peak concentration dependent activity) and measured serum level can provide an optimal target concentration for the individual drug and patient.Modern anti-infective management for ICU patients includes more than the choice of drug and prompt application. Individual dosing, optimized prolonged infusion time and TDM give way to new and promising opportunities in infection control.

[Quality assurance concepts in intensive care medicine]

Intensive care medicine (ICM) is characterized by a high degree of complexity and requires intense communication and collaboration on interdisciplinary and multiprofessional levels. In order to achieve good quality of care in this environment and to prevent errors, a proactive quality and error management as well as a structured quality assurance system are essential. Since the early 1990s, German intensive care societies have developed concepts for quality management and assurance in ICM. In 2006, intensive care networks were founded in different states to support the implementation of evidence-based knowledge into clinical routine and to improve medical outcome, efficacy, and efficiency in ICM. Current instruments and concepts of quality assurance in German ICM include core intensive care data from the data registry DIVI REVERSI, quality indicators, peer review in intensive care, IQM peer review, and various certification processes. The first version of German ICM quality indicators was published in 2010 by an interdisciplinary and interprofessional expert commission. Key figures, indicators, and national benchmarks are intended to describe the quality of structures, processes, and outcomes in intensive care. Many of the quality assurance tools have proved to be useful in clinical practice, but nationwide implementation still can be improved.

Quantitative CT imaging of the spatio-temporal distribution patterns of vasa vasorum in aortas of apoE-/-/LDL-/- double knockout mice

OBJECTIVE

To investigate the distribution of vasa vasorum (VV) relative to advanced atherosclerotic lesions (calcified, fibrotic or hemorrhaged) along the aortic wall of apoE-/-/LDL-/- mice at the age of 25 and 80 weeks using high-resolution nano-CT.

METHODS

Aortas from male apoE-/-/LDL-/- mice at the age of 25 weeks (n=4) and 80 weeks (n=7) were infused in situ with contrast agent and harvested for scanning with nano-CT. The spatial distribution of vasa vasorum [number and area/cross-section (mm2)] was compared to aortic luminal cross-sectional area and plaque cross-sectional area in the ascending aorta, aortic arch and descending aorta. Results were complemented with co-localized histology.

RESULTS

The number and total luminal cross-sectional area of VV showed a significant decrease in the ascending aorta and aortic arch from 25 to 80 weeks but not in the descending aorta. The number and cross-sectional area of VV showed significant local differences depending on whether it was near a fibrotic, and hemorrhaged or calcified plaque in animals at the age of 80 weeks. Area of VV progressively increased along the aorta from least in the ascending aorta<aortic arch<descending aorta in animals at the age of 80 weeks and is inverse in animals aged 25 weeks.

CONCLUSION

Atherosclerotic lesion type is correlated to the number and cross-sectional area of VV in different aortic segments in apoE-/-/LDL-/- mice. The chronological development of VV along the aorta proceeds distally from the ascending aorta and aortic arch.

[Patient surveys as an element of quality management in outpatient care: development and assessment of a questionnaire]

OBJECTIVE

The present study was designed to develop and assess a questionnaire measuring all relevant quality dimensions of general practice care from the patients' perspective. Furthermore, the study aimed to evaluate the implementation of a patient survey in outpatient care.

METHODS

Based on the Kölner Patientenfragebogen (KPF) and by developing some additional new items, we created the new questionnaire KPF-A (Kölner Patientenfragebogen-ambulant) which covers all relevant aspects of outpatient care. The questionnaire was distributed to the patients of 41 GP's and specialists in ambulatory care from different regions of Germany. N=3188 patients were included in the sample. We used these data to assess some selected psychometric characteristics of the KPF-A. Factor analysis was used to examine the underlying factor structure. A qualitative study was conducted to evaluate the implementation of the patient survey. Therefore, all N=41 doctors involved were asked to complete five open questions concerning their experience.

RESULTS

Most scales of the KPF-A showed good psychometric characteristics in the present study. Factor analysis revealed a two-factors solution for the new items representing the dimensions "professional competence" and "medical equipment". We have not yet been able to find a sound factor solution for those items representing the dimension "Staff and Organisation". The results of the qualitative study revealed a satisfying implementation of the patient survey in daily routine from the doctors' perspective. The length of the questionnaire was criticised by some participants. In the design of the study patients were supposed to fill in the questionnaires after consultation. This turned out to be difficult. We therefore modified the KPF-A so that patients can fill it in either before or after consultation.

Antikörperkontrollierte zytostatische Therapie des malignen Thymoms bei begleitender Myasthenia gravis

In a 46-year-old female patient with malignant thymoma and concomitant myasthenia gravis relapse with gravitational metastases occurred 6 1/2 years after the first operation. Metastases could be removed surgically only partially and were subsequently irradiated with 50 Gy. After 3 1/2 years renewed metastatic growth occurred. Until then the concomitant myasthenia had been stable during treatment with pyridostigmine and azathioprin and intermittent prednisone; acetylcholine receptor antibody titres had remained largely stable. Combined cytostatic treatment with vincristine, cyclophosphamide, prednisone and doxorubicin or cisplatin led to regression of metastases during the observation period of 1 1/2 years and at the same time to stabilisation of the myasthenia. Acetylcholine receptor antibody titres decreased and this was roughly paralleled by clinical improvement. Whereas there is no obvious correlation of antibodies against acetylcholine-receptor protein and tendency of tumour growth there is good agreement with the course of the accompanying myasthenia.

[Management of the operation room in an university hospital]

The heart of any surgical department is the operation room area. Any disturbances in the daily routine will affect the work flow of the whole hospital. As an example the major complaints of a university surgical department regarding workflow and communication are outlined. To solve these problems a team "OR organization" was established, which started the work based on a new developed OR statute. Within a short period the contentment of the employees as well as the workflow improved. But as a matter of fact, even in the following years of central OR management there is still the need to further stabilize the system and carefully improve the controlling system.

An unusual case of early fulminant post-traumatic fat embolism syndrome

A multiple-injured patient developed a very early onset fulminant fat embolism syndrome that was partially masked by haemorrhagic shock. Despite early diagnosis by transoesophageal echocardiography and aggressive symptomatic treatment, there was a rapid evolution to death. Post mortem examination revealed the presence of both pulmonary and systemic fat emboli. This case highlights the ever present risk of masked fat embolism syndrome shortly after trauma.

Laterale Ischiadikusblockaden

In the present study we examined 41 volunteers using magnetic resonance imaging to obtain biometric data of the thigh used for a planned blockade of the sciatic nerve via the lateral approach. At a needle entry point 12 cm proximal to the gap of the knee joint at the posterior border of the M. vastus lateralis, the sciatic nerve lies on average at a depth of 5.2 cm (39% of the femoral diameter at this site) with an angle of 10.9 degrees to the horizontal in a dorsal direction. Here the popliteal artery lies on average at a depth of 6.4 cm (48% of the femoral diameter) with an angle of 4.7 degrees to the horizontal in a ventral direction. At the marked point in the middle between the gap of the knee joint and the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at an average depth of 6.2 cm (40% of the femoral diameter at this site) with an angle of 8.2 degrees in a dorsal direction. At a marked point 5 cm distal of the trochanter major at the posterior border of the M. vastus lateralis, the sciatic nerve is at a depth of 9.1 cm at a dorsal angle of 15.5 degrees (49% of the femoral diameter). The lateral blockade of the sciatic nerve at different sites of the thigh is a technique which is easy to plan with the presented biometric data. The popliteal artery could be reached only at the distal puncture point using a deep puncture and an angle in the ventral direction.

[Possibilities in improving patients's turn-over coordination in the OR of an University Hospital]

An efficient Operating Room (OR) management might increase the cost-effectiveness of an OR. For this purpose, we have evaluated the coordination and the times of the solitary processes that are involved in the patient turnover. The mean time between skin suture of the preceding patient and incision of the following patient (SI-time) was, depending on the type of operation, between 44 and 78 minutes. Mean empty-room time (ERT) was 7 minutes. SI-times depended on various factors, including the times necessary to discharge the preceding patient from the OR and the times necessary for induction of anesthesia or for preparation of the OR. Altogether, our data provide evidence for the fact, that optimisation of the patients turnover can decrease SI-times between 10-15 minutes. Although this period appears too short to reliably allow an additional scheduled operation during regular working hours, an improved coordination may result in reduced overtimes of the OR-staff and thus should increase staff satisfaction.

[Fatal outcome after multiple trauma. The thoracic injury as the decisive factor]

In patients suffering from multiple injury, chest trauma is often the main cause of fatality. A case report is given and the literature reviewed.A 49 years old motorcyclist hit a car frontally in a road accident. After primary stabilization and first clinical care, he was transferred to our trauma centre because of severe chest injury, suspected pericardial effusion and lesion of the thoracic aorta. Initial diagnostics (plain radiographs, CT scan of thorax, abdominal ultrasound, echocardiography) showed left-sided serial rib fractures, a fracture of the left scapula, a hematopneumothorax left-sided, bilateral lung contusion, a small pneumothorax of the right side, a minimal pericardial effusion and a small splenic hematoma. The patient was treated in the intensive care unit, and the situation was initially stable. After 12 h, respiration deteriorated and a bronchoscopy showed filling of the airways with mucous fluid. The CT scan showed a worsening of the pulmonary damage and increasing pericardial fluid compression. A pericardiotomy was carried out, but the situation remained unstable. The patient was treated with invasive ventilation (PEEP>10, FiO2>0,5). Sudden severe bleeding out of left lower lobe was managed by thoracotomy and lobectomy. The patient remained unstable and died 95 h after the accident. This case shows that the severity of chest trauma does not necessarily correlate with the initial clinical and radiological findings. Even with all diagnostic and therapeutic procedures, a fatal outcome could not be prevented. This demonstrates the role of chest injury as a major and unforeseeable cause of death in multiple trauma patients.

Balanced Scorecard

The change in hospital funding with diagnosis related groups (DRG), medical advances as well as demographic changes will call for new quantitative and qualitative standards imposed on German hospitals. Increasing costs and competition in the health care sector requires new and innovative strategies for resource management. Today's policy is mainly defined by rationing and intensified workload. The introduction of DRGs will presumably further constrict management perspectives on pure financial aspects. However, to ensure future development, compassionate services and continued existence of hospitals, a balance of seemingly conflicting perspectives, such as finance, customer, process, learning and growth are of utmost importance. Herein doctors and nurses in leading positions should play a key role in changing management practice. For several years the balanced scorecard has been successfully used as a strategic management concept in non-profit organizations, even in the health care sector. This concept complies with the multidimensional purposes of hospitals and focuses on policy deployment. Finally it gives the opportunity to involve all employees in the original development, communication and execution of a balanced scorecard approach.

[OR-manager: surgeon or anaesthetist?]

The heart of any surgical department is the operating room (OR) area. Any disturbances in the daily routine will affect the work flow of the whole hospital. On account of its central function, with numerous connections to other departments, the OR is the crystallisation point for deficiencies in various events and processes. As an example, the major complaints made by a surgical department regarding workflow and communication are outlined. To solve these problems, an "OR organization" team was established, which worked on the basis of a newly developed OR statute. Within 1 year the employees were more contentment and the workflow had improved. However, even in the second year of central OR management there is still the need to further stabilize the system as mismanagement still occurs.

Stress response during weaning after cardiac surgery

We compared the effects of weaning using synchronized intermittent mandatory ventilation (SIMV) with the use of biphasic positive airway pressure (BIPAP) on the stress response, oxygen uptake (VO2) and work of breathing (WOB) in 10 patients after aortocoronary bypass surgery. All three ventilatory settings were investigated in each patient, for example, volume-controlled mechanical ventilation immediately before weaning was followed, in randomized order, by both SIMV and BIPAP. In addition to routine monitoring of continuous and respiratory state, we measured VO2, WOB, and pressure-time product (PTP) as well as the plasma concentrations of epinephrine, norepinephrine, ACTH, cortisol, vasopressin, and prolactin. Although respiratory rate (f), WOB and PTP were greater with both SIMV and BIPAP when compared with control, other variables did not change with the ventilatory mode. In conclusion, weaning from mechanical ventilation using partial support modes does not affect the postoperative stress response in patients who have had uncomplicated cardiac surgery.

Does gastric juice pH influence tonometric PCO2 measured by automated air tonometry?

To determine the influence of changes in gastric juice pH due to intravenous administration of pentagastrin and omeprazole on intramucosal regional PCO2 (Pr(CO2)), we investigated 17 healthy human volunteers. Gastric juice pH was obtained from a glass pH electrode for continuous gastric juice pH measurement and Pr(CO2))was measured by using automated air tonometry. After baseline (8:00 A.M.-9:00 A.M.) the subjects received 0.6 microg/kg/h pentagastrin intravenously for 1 h (9:00 A.M.-10:00 A.M., after stimulation 10:00 A.M.-11:00 A.M.) and 40 mg omeprazole intravenously (after omeprazole 11:00 A.M.-3:00 P.M.). Following pentagastrin administration gastric juice pH significantly decreased from 1.2 +/- 0.4 to 0.6 +/- 0.4 (mean +/- SD, p < 0.007, versus baseline), whereas omeprazole transiently increased luminal pH up to 4.4 +/- 1.7 (p < 0.007 versus baseline). These subsequent changes in gastric juice pH were accompanied by a significant increase in Pr(CO2) from 48 +/- 12 to 61 +/- 17 mm Hg (p < 0.007 versus baseline) and a decrease to 44 +/- 5 mm Hg (p < 0.002 versus pentagastrin), respectively. A gastric juice pH > 4 considerably reduces mean gastric Pr(CO2) and interindividual variability. Thus omeprazole may improve the validity of gastric tonometry data.

Gastrointestinal tract resuscitation in critically ill patients

Particular research interest is currently focusing on the resuscitation of the gastrointestinal tract, because the gut is regarded to be both the "canary of the body", i.e. a sentinel organ during situations of compromised oxygen or substrate supply, as well as the "motor of multiple organ failure". Several therapeutic strategies have recently been proposed for the resuscitation of this organ system, aimed primarily at the augmentation of blood flow and oxygenation but also integrating nutritional or metabolic support and antioxidant administration.

Hepatic oxygen exchange and energy metabolism in hyperdynamic porcine endotoxemia: effects of the combined thromboxane receptor antagonist and synthase inhibitor DTTX30

OBJECTIVE

We compared the effects of thromboxane receptor antagonist and synthase inhibitor DTTX30 on systemic and liver blood flow, oxygen (O2) exchange and energy metabolism during 24 h of hyperdynamic endotoxemia with untreated endotoxemia.

DESIGN

Prospective, randomized, experimental study with repeated measures.

SETTING

Investigational animal laboratory.

SUBJECTS

Twenty-seven domestic pigs: 16 during endotoxemia with volume resuscitation alone; 11 with endotoxemia, volume resuscitation and treatment with DTTX30.

INTERVENTIONS

Continuous infusion of Escherichia coli lipopolysaccharide (LPS) for 24 h together with volume resuscitation. After 12 h of endotoxemia, DTTX30 was administered as a bolus of 0.12 mg kg-1 followed by 12 h continuous infusion of 0.29 mg kg-1 per h.

MEASUREMENTS AND RESULTS

DTTX30 effectively counteracted the endotoxin-associated increase in TXB2 levels and increased 6-keto-PGF1 alpha with a significant shift of the thromboxane/prostacyclin ratio towards predominance of prostacyclin. DTTX30 prevented the significant progressive endotoxin-induced decrease of mean arterial pressure (MAP) below baseline while maintaining cardiac output (CO), and increased the fractional contribution of liver blood flow to CO without an effect on either hepatic O2 delivery or O2 uptake. The mean capillary hemoglobin O2 saturation (HbO2) on the liver surface and HbO2 frequency distributions remained unchanged as well.

CONCLUSIONS

DTTX30 significantly attenuated the endotoxin-induced derangements of cellular energy metabolism as reflected by the diminished progressive decrease in hepatic lactate uptake rate and a blunted increase in hepatic venous lactate/pyruvate ratios. While endotoxin significantly increased the endogenous glucose production (EGP) rate, EGP returned towards baseline levels in the DTTX30-treated group. Thus, in our model DTTX30 resulted in hemodynamic stabilization concomitant with improved hepatic metabolic performance.

Hepatic O2 exchange and liver energy metabolism in hyperdynamic porcine endotoxemia: effects of iloprost

OBJECTIVE

To compare the effects of a 12 h continuous infusion of iloprost, a stable prostacyclin analogue, on hepatic blood flow (Qliv), O2 exchange, and energy metabolism during a 24 h hyperdynamic, porcine endotoxemia with volume resuscitation alone.

DESIGN

Prospective, randomized, experimental study with repeated measures.

SETTING

Investigational animal laboratory.

SUBJECTS

Twenty-eight domestic pigs: 16 animals during endotoxemia with volume resuscitation alone (ETX), 12 with endotoxemia, volume resuscitation, and treatment with iloprost (ILO).

INTERVENTIONS

Endotoxemia was initiated by continuous infusion of E. coli lipopolysaccharide. Animals were resuscitated with hetastarch, aimed at maintaining a MAP of > 60 mmHg. After 12 h of endotoxemia, iloprost was administered for 12 h in the treatment group, titrated to avoid pharmacologically induced hypotension (MAP < 60 mmHg).

MEASUREMENTS AND RESULTS

Iloprost significantly increased Qliv, with no effect on hepatic O2 delivery. Mean capillary hemoglobin O2 saturation (HbScO2) on the liver surface, as well as HbScO2 frequency distributions--a measure of microcirculatory O2 availability--remained unchanged. Treatment with iloprost, however, significantly attenuated the endotoxin-induced derangements of cellular energy metabolism as reflected by the diminished progressive decrease in hepatic lactate uptake rate and a blunted increase in hepatic venous lactate/pyruvate ratios. While endotoxin significantly increased endogenous glucose production (EGP) rate, iloprost restored EGP to normal at the end of the experiment.

CONCLUSIONS

Thus, in a clinically relevant model of human sepsis, iloprost did not produce potential adverse effects but rather ameliorated hepatic metabolic disturbances and, thereby, hepatic energy balance.

Effects of the combined thromboxane receptor antagonist and synthase inhibitor DTTX-30 on intestinal O2-exchange and energy metabolism during hyperdynamic porcine endotoxemia

Sepsis may lead to deranged thromboxane-prostacyclin ratio with consecutive organ dysfunction. Because of the suggested role of the gut in the pathogenesis of septic shock and multiple organ failure, we investigated the effects of the novel dual thromboxane synthase inhibitor and receptor antagonist DTTX-30 (TRASI) on intestinal tissue perfusion, O2 kinetics, and energy metabolism over 24 h of hyperdynamic, normotensive porcine endotoxemia. Before, 12, 18, and 24 h after starting continuous i.v. endotoxin (LPS), we measured portal venous (PV) blood flow, intestinal oxygen extraction (iO2ER), intracapillary hemoglobin O2 saturation (HbO2%) of the ileal wall, intramucosal ileal PCO2, PV lactate-pyruvate (L-P) ratio, and plasma levels of thromboxane and prostacyclin. Treatment with TRASI (0.12 mg/kg i.v. bolus injection followed by an infusion of 0.29 mg/kg/h) initiated after 12 h of LPS infusion markedly reduced the plasma thromboxane levels and attenuated the LPS-induced fall in systemic vascular resistance, resulting in hemodynamic stabilization. TRASI did not influence the LPS-induced increase in PV blood flow nor intracapillary HbO2%, thus reflecting unchanged microcirculatory O2 availability and decreased iO2ER, possibly because of reduced O2 requirements. Nevertheless, TRASI prevented the LPS-induced increase in the PV L-P ratio, attenuated the progression of the ileal mucosal-arterial PCO2 gap, and tended to attenuate the gradual fall of PV pH. Hence, compounds like TRASI may beneficially influence LPS-related derangements of gut energy metabolism.

Determination of molecular geometry by high-order multiple-quantum evolution in solid-state NMR

The principles of molecular geometry determination by high-quantum heteronuclear local field spectroscopy in solid-state NMR are discussed. The extreme multiple-quantum coherences in a cluster of nuclear spins are allowed to evolve in the presence of heteronuclear through-space couplings to two spins of a different type. The multiple-quantum dephasing curve is independent of the homonuclear spin-spin couplings and may be described in terms of geometric parameters. The triple-quantum version of the experiment is demonstrated by determining the psi torsion angle in a [(15)N(2), (13)C(3)]-labeled sample of the peptide ala-ala-gly. Two regions of torsion angle space fit the experimental data, one in the neighborhood of -152 degrees and one in the neighborhood of +161 degrees. The latter determination is in excellent agreement with the X-ray estimate of +160.5 degrees.

Mechanistic aspects of dihydrogen activation and transfer during asymmetric hydrogenation in supercritical carbon dioxide

A new "CO2-philic" chiral rhodium diphosphinite complex was synthesized and applied as catalyst precursor in the asymmetric hydrogenation of dimethyl itaconate in scCO2, scC2H6 and various liquid organic solvents. Deuterium labeling studies and parahydrogen-induced polarization (PHIP) NMR experiments were used to provide the first detailed mechanistic insight into the activation and transfer of the dihydrogen molecule during hydrogenation in scCO2. Chemical interactions between CO2 and reactive intermediates of the catalytic pathway could be excluded as possible explanations for the experimentally verified difference in the catalytic behavior in scCO2 and hexane.

[Expression of AC133 vs. CD34 in acute childhood leukemias]

AC133, a newly discovered antigen on human progenitor cells, demonstrating 5-transmembranous domains is expressed by 30-60% out of all CD34+ cells. Our aim therefore was to investigate the extent of human stem-/progenitor cells expressing AC133 antigen in umbilical cord blood, peripheral blood without or following an application of granulocyte-colony stimulating factor (rhG-CSF). The main task was the investigation of bone marrow aspirates derived from children suffering from newly diagnosed acute leukemias, as well as from patients with a relapse or during a complete remission. The determination of antigen expression was done by application of flow cytometry (FACScan analysis) and the usage of newly developed monoclonal antibodies (AC133/1 and AC133/2; Miltenyi Biotec GmbH) in combination with monoclonal antibody directed against CD34-antigens (HPCA-2; BD). Our studies till now show average percentages in umbilical cord blood derived from 43 newborns about 0.294 +/- 0.165% AC133+ vs. 0.327 +/- 0.156% CD34+ hematopoietic stem-/progenitor cells (HSPC). In peripheral blood from 11 healthy donors we verified up to 0.15% CD34+ as well as AC133+ HSPC's. The concentration of progenitor cells was found to be obviously higher in peripheral blood from children with various diseases (neuroblastoma, rhabdomyosarcoma, ALL/AML) and undergoing application with rhG-CSF in order to be prepared for PBSC-transplantation. In those cases we found up to 3.51% AC133+ cells as well as slightly higher values (3.94%) for CD34 antigens. Additionally we quantified 128 bone marrow (BM) samples for AC133+ and CD34+ cells. In 10 BM samples, derived from patients without any neoplasia, the CD34+ cells were about 0.03% and 1.49%, whereas AC133 values were up to 0.64%. Bone marrow aspirates from 53 children with acute leukemias at time of diagnosis (ALL: n = 41/AML: n = 12) have been immunophenotyped and leukemic blast cells have been proved for AC133- and CD34 antigen expression. 32/41 (78%) of lymphoblastic leukemic cells showed to be positive for CD34 antigen and 24/41 (58%) demonstrated AC133 antigens. Interestingly there were 2 ALL-patients with pathological blast cells positive for AC133 but lacking of any CD34 antigens. 42% (5/12) of investigated AML patients showed CD34+ phenotype, on the other hand there were only 25% (3/12) with AC133+ phenotype. Similar values were found in relapsed patients (n = 18). In BM samples from patients during complete remission (n = 47) we could detect percentages up to 5.55% for CD34 and up to 1.25% for AC133 positive stem-/progenitor cells. Such quite high data may be explained by occasionally application of rhG-CSF therapy. Our results till now lead to the conclusion, that it seems to be useful, to recruit quantification of CD34+ HPSC by additionally detecting AC133 antigens. This new stem cell marker (AC133) may be of great value in case of autologous peripheral blood stem cell transplantation (PBSCT) because it could be an alternative to the usual CD34+ MACS selection system.

[The effect of hepatosplanchnic circulation in treatment of trauma and sepsis. Beyond O2-supply O2-uptake relationship?]

Sepsis and SIRS are characterised by increased hepatosplanchnic blood flow and oxygen transport due to sepsis-associated hypermetabolism with enhanced oxygen uptake. Regional hypermetabolism may be linked with a mismatch of oxygen availability and demand potentially resulting in a pathological splanchnic oxygen uptake/supply dependency. Splanchnic hypermetabolism has been hypothesised to be due to increased hepatic gluconeogenesis caused by accelerated glucose precursor uptake resulting from increased release from the peripheral tissues. This increased precursor efflux is triggered by cytokines. The response of splanchnic haemodynamics and oxygen kinetics, however, to therapeutic interventions does not necessarily parallel the different metabolic pathways. Therefore, understanding of both tissue perfusion and oxygenation as well as metabolism is pivotal for evaluating the effects of different therapeutic strategies in intensive care medicine.

Multiple-quantum relaxation in the magic-angle-spinning NMR of 13C spin pairs

We determine the decay rate constants of zero-, double- and single-quantum coherence for 13C spin pairs in magic-angle-spinning solid-state NMR. The double-quantum coherence is excited by a C7 pulse sequence and converted into zero-quantum coherence by a frequency-selective pair of pi/2 pulses. The zero-quantum coherence is reconverted into observable magnetization by a second pair of pi/2 pulses followed by a second C7 sequence. In a magnetically dilute system where the 13C-13C distance is 0.296 nm, the relaxation rate constants are consistent with a model of uncorrelated random fields at the two labeled 13C sites. In a fully-labelled system with a short 13C-13C distance of 0.153 nm, the measured rate constants are inconsistent with the uncorrelated random field model.

Changes in gastric intramucosal pH following mesenteric traction in patients undergoing pancreas surgery

BACKGROUND/AIM

During major abdominal surgery, mesenteric traction (MT) may result in hemodynamic instability mainly due to endogenous prostacyclin release. Gastric intramucosal pH (pHi) and PiCO2 are indicators of splanchnic tissue perfusion with a predictive value for the postoperative outcome. We investigated the influence of MT on gastric pHi and on postoperative outcome in patients undergoing pancreas surgery.

METHODS

Forty-six consecutive patients scheduled for pancreas surgery were investigated. We registered hemodynamics and pHi by gastric tonometry and documented postoperative outcome (complications, hospital stay). Baseline data (T0) were recorded after skin incision. Further assessments followed 30, 60 and 120 min after intentional MT (T1-3) and at the end of surgery (T4).

RESULTS

Thirty-three patients demonstrated a decrease in mean arterial pressure (MAP) following MT, whereas 13 patients showed entirely stable hemodynamics. The significant reduction in MAP in patients with an MT response was not associated with changes in pHi as compared to patients with no response (stable MAP) (T0 7.34 +/- 0.08 vs. 7.35 +/- 0.06; T1 7.34 +/- 0.05 vs. 7.32 +/- 0.07; T2 7.32 +/- 0. 05 vs. 7.31 +/- 0.08; T3 7.32 +/- 0.05 vs. 7.32 +/- 0.07; T4 7.26 +/- 0.1 vs. 7.27 +/- 0.08; mean +/- SD, MT response vs. no response). Neither MT response nor gastric intramucosal acidosis as evidenced by a pHi <7.32 at the end of surgery predicted postoperative complications or longer hospital stay.

CONCLUSION

No deterioration of gastric pHi was found, which could reflect acceptable splanchnic perfusion and oxygenation despite systemic blood pressure reactions in patients experiencing an MT response.