[Intraoperative vascular air embolism : Evidence for risks, diagnostics and treatment]. / Intraoperative vaskuläre Luftembolie : Evidenz bei Risiko, Diagnostik und Therapie.

The entry of gases into the vascular system is called vascular air embolism (VAE). The blocking of the pulmonary circulation by VAE can lead to fulminant right-sided heart failure and cardiocirculatory arrest. A VAE can occur at any time if there is an open connection between the environment and a venous vessel with subatmospheric pressure. This situation occurs during ear nose throat surgery, hip surgery, surgery of the lesser pelvis or breast surgery, if the surgical field is above the level of the heart; however, a VAE can also occur during routine tasks, such as insertion or removal of a central venous catheter or during endoscopic procedures with the insufflation of gas.Because during these procedures VAE is not the main focus of the anesthesia or surgery personnel, in such situations its sudden unexpected occurrence can have severe consequences. In contrast, in cardiac surgery or neurosurgery the risk of intraoperative VAE is much better known. In procedures with a higher risk of a clinically relevant VAE, a patent foramen ovale should be ruled out by preoperative transesophageal echocardiography (TEE). Intraoperatively TEE is the most sensitive procedure not only to detect a VAE but also to visualize the clinical expression, e.g. acute right heart overload.The avoidance of an initial and repeated air embolism is the primary measure to minimize the incidence and severity of VAE.Intraoperatively the following measures should be undertaken: excellent communication between anesthesia and surgery personnel with predetermined actions, maintenance of normal volume, patient positioning with minimal difference in height between heart and head, state of the art surgical technique with closure of potential air entry sites, sufficient detection of air by TEE, repeated jugular vein compression during neurosurgery, intraoperative Trendelenburg positioning of the patient during persisting or clinically evident VAE, differentiated adjustment of ventilatory settings and catecholamine treatment, aspiration of the blood-air mixture (air lock) at the junction of the superior vena cava and right atrium through a large bore central venous line and keeping check of the coagulation status.

Enolase from Trypanosoma cruzi is inhibited by its interaction with metallocarboxypeptidase-1 and a putative acireductone dioxygenase.

Purification of enolase (ENO) from the cytosol of Trypanosoma cruzi indicated that it may interact with at least five other proteins. Two of them were identified as metallocarboxypeptidase-1 (TcMCP-1) and a putative acireductone dioxygenase (ARDp). Subcellular localization studies confirmed the presence of ARDp in the cytosol, as is the case for ENO and TcMCP-1. Analysis of the ARDp sequence showed that this protein has two domains, an N-terminal ARD and a C-terminal TRP14 (thioredoxin-related protein) domain. The interactions between ENO, TcMCP-1 and ARDp were confirmed for the natural proteins from the trypanosome (using size-exclusion chromatography and co-immunoprecipitation from a cytosolic fraction) and recombinant forms (using ELISA ligand-binding assay and ENO activity assays). The ELISA ligand-binding assays permitted to verify the optimal physicochemical conditions for the interactions (representative for the physiological conditions) and to determine the affinity constants (Kd): ENO/ARDp: 9.54 ±â€¯0.82 nM, ARDp/ENO 10.05 ±â€¯1.11 nM, and ENO/TcMCP-1: 5.66 ±â€¯0.61 nM. The data also show that the interaction between TcMCP-1 and ARDp is mediated by ENO acting as a "bridge". Furthermore, considerable inhibition of the ENO activity, up to 85%, is observed when the enzyme interacts with TcMCP-1 and ARDp simultaneously. All these data confirm that the interaction between ENO, TcMCP-1 and ARDp, occurring in T. cruzi's cytosol, modulates the ENO activity and suggest a possible physiological mechanism for regulation of the ENO activity by the protein-protein interaction.

[Neurophysiological monitoring during surgical procedures]. / Neurophysiologisches Monitoring bei operativen Eingriffen.

The application of intraoperative neurophysiological monitoring (IONM) is gaining more and more importance in daily clinical practice. The use of IONM allows the localization of neural structures and to control functioning of the peripheral and central nervous systems in anesthetized patients. This enables surgeons to identify and to protect neural structures and cerebral areas. The use of IONM also enables anesthesiologists to adjust anesthesia and cardiopulmonary therapy to the individual needs of the patient. Thereby, it may be possible to reduce the incidence of postoperative delirium and the incidence of postoperative cognitive deficits. To exploit the full potential anesthesiologists and surgeons must be able to use the methods of IONM safely and understand the results; therefore, basic knowledge of the technology, options and limitations of IONM is necessary. It is also important to be aware of the influence of anesthetics on the methods of IONM. Total intravenous anesthesia (TIVA) is the anesthetic method of choice, because it has only minimal influence on IONM methods. It is important to avoid bolus injections of hypnotics to achieve stable blood concentrations. Long- acting neuromuscular blocking agents should be avoided, because they disturb the signals of electromyography and motor-evoked potentials. By using IONM anesthesiologists and surgeons can identify changes in the function of the peripheral and central nervous system prior to irreversible damage.

Clopidogrel Resistance in Neurovascular Stenting: Correlations between Light Transmission Aggregometry, VerifyNow, and the Multiplate.

BACKGROUND AND PURPOSE: Clopidogrel resistance is blamed for thromboembolic complications in neurovascular stent placement. Platelet-function assays are weakly standardized. The aim of this study was to correlate the results of 3 different platelet-inhibition measurements (from light transmission aggregometry, the VerifyNow P2Y12 test, and the Multiplate analyzer) and their relation to periprocedural thromboembolic complications in elective neurovascular stent placement. MATERIALS AND METHODS: Clopidogrel resistance was determined on the day of the intervention according to predefined platelet reactivity cutoff values. All 3 tests were performed in 103 consecutive neurovascular stent-placement procedures in 97 patients (extracranial, n = 77; intracranial, n = 26). RESULTS: The clopidogrel resistance rates were 47.6% (light transmission aggregometry), 50.5% (VerifyNow), and 35.9% (Multiplate). In 67% of the patients, clopidogrel resistance was present according to at least one method. The correlations of qualitative results that classified a patient as responsive or resistant to clopidogrel were 67.9% for light transmission aggregometry with VerifyNow, 77.7% for light transmission aggregometry with the Multiplate, and 66% for VerifyNow with the Multiplate. Periprocedural thromboembolic complications (n = 9) occurred more frequently in patients who were determined by all 3 methods to be clopidogrel resistant. The difference was most pronounced with light transmission aggregometry (complication rates, 14.4% [clopidogrel-resistant patients] vs 3.7% [clopidogrel-responsive patients]). Sensitivity and specificity rates of clopidogrel resistance in relation to embolic complications were, respectively, 78% and 55% for light transmission aggregometry, 67% and 51% for VerifyNow, and 44% and 67% for the Multiplate. CONCLUSIONS: Clopidogrel resistance is a frequent finding in patients who undergo neurovascular stent placement. The correlations among the different testing methods are only modest and differ considerably. Light transmission aggregometry results seem to correlate with thromboembolic complications more accurately than with VerifyNow and Multiplate point-of-care methods.

[Quality assurance at the interface between anesthesia and transfusion medicine]. / Qualitätssicherung an der Schnittstelle zwischen Anästhesie und Transfusionsmedizin.

BACKGROUND: The current situation in hospitals is characterized by financial limitations and simultaneously by increasing demands on quality and safety. The operative interface between anesthesia and transfusion medicine affects both factors. AIM: A detailed analysis was performed to evaluate the process quality at this operative interface at the University Hospital of Göttingen. The aim of the project was to revise und develop the structures and responsibilities at this interface, to dispose of weak points and to realize the optimization potential in the supply of blood products. MATERIAL AND METHODS: A databank-based electronic data processing solution was established with the clear definition of responsibilities for the various workflow procedures and the written documentation of these definitions in standard operating protocols. In order to guarantee the necessary transparency a routine reporting system to the department of surgery was established. In addition, a continuous further development of the blood supply standard based on electronic report data was implemented. RESULTS: By implementing the above named measures the rate of supplied to transfused blood products could be increased from 43.1 % to 55.7 %. The compliance with the blood supply standard improved continually over the first 18 months from 60.3 % to 92.3 %. The rate of supplied blood product deliveries without subsequent operation could be reduced from 9.0 % to 4.6 %. As a result of this optimization the supply costs in the internal cost allocation were reduced from 9,406  to 3,544 . CONCLUSION: The measures described are appropriate to cost-effectively improve quality and patient safety. The optimization measures presented in this article can be implemented in other hospitals to increase quality and safety after individual adjustment to the local circumstances.

Glycosomal targets for anti-trypanosomatid drug discovery.

Glycosomes are peroxisome-related organelles found in all kinetoplastid protists, including the human pathogenic species of the family Trypanosomatidae: Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp. Glycosomes are unique in containing the majority of the glycolytic/gluconeogenic enzymes, but they also possess enzymes of several other important catabolic and anabolic pathways. The different metabolic processes are connected by shared cofactors and some metabolic intermediates, and their relative importance differs between the parasites or their distinct lifecycle stages, dependent on the environmental conditions encountered. By genetic or chemical means, a variety of glycosomal enzymes participating in different processes have been validated as drug targets. For several of these enzymes, as well as others that are likely crucial for proliferation, viability or virulence of the parasites, inhibitors have been obtained by different approaches such as compound libraries screening or design and synthesis. The efficacy and selectivity of some initially obtained inhibitors of parasite enzymes were further optimized by structure-activity relationship analysis, using available protein crystal structures. Several of the inhibitors cause growth inhibition of the clinically relevant stages of one or more parasitic trypanosomatid species and in some cases exert therapeutic effects in infected animals. The integrity of glycosomes and proper compartmentalization of at least several matrix enzymes is also crucial for the viability of the parasites. Therefore, proteins involved in the assembly of the organelles and transmembrane passage of substrates and products of glycosomal metabolism offer also promise as drug targets. Natural products with trypanocidal activity by affecting glycosomal integrity have been reported.

Antitrypanosomal compounds from the essential oil and extracts of Keetia leucantha leaves with inhibitor activity on Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase.

Keetia leucantha is a West African tree used in traditional medicine to treat several diseases among which parasitic infections. The dichloromethane extract of leaves was previously shown to possess growth-inhibitory activities on Plasmodium falciparum, Trypanosoma brucei brucei and Leishmania mexicana mexicana with low or no cytotoxicity (>100 µg/ml on human normal fibroblasts) (Bero et al. 2009, 2011). In continuation of our investigations on the antitrypanosomal compounds from this dichloromethane extract, we analyzed by GC-FID and GC-MS the essential oil of its leaves obtained by hydrodistillation and the major triterpenic acids in this extract by LC-MS. Twenty-seven compounds were identified in the oil whose percentages were calculated using the normalization method. The essential oil, seven of its constituents and the three triterpenic acids were evaluated for their antitrypanosomal activity on Trypanosoma brucei brucei bloodstream forms (Tbb BSF) and procyclic forms (Tbb PF) to identify an activity on the glycolytic process of trypanosomes. The oil showed an IC(50) of 20.9 µg/ml on Tbb BSF and no activity was observed on Tbb PF. The best antitrypanosomal activity was observed for ursolic acid with IC(50) of 2.5 and 6.5 µg/ml respectively on Tbb BSF and Tbb PF. The inhibitory activity on a glycolytic enzyme of T. brucei, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was also evaluated for betulinic acid, olenaolic acid, ursolic acid, phytol, α-ionone and ß-ionone. The three triterpenic acids and ß-ionone showed inhibitory activities on GAPDH with oleanolic acid being the most active with an inhibition of 72.63% at 20 µg/ml. This paper reports for the first time the composition and antitrypanosomal activity of the essential oil of Keetia leucantha. Several of its constituents and three triterpenic acids present in the dichloromethane leaves extract showed a higher antitrypanosomal activity on bloodstream forms of Tbb as compared to procyclic forms, namely geranyl acetone, phytol, α-ionone, ß-ionone, ursolic acid, oleanolic acid and betulinic acid. The four last compounds were proven to be inhibitors of trypanosomal GAPDH, which may in part explain these antitrypanosomal activities.

Carotidynia: magnetic resonance imaging and ultrasonographic imaging of a self-limiting disease.

This article describes the characteristic symptoms of carotidynia and the diagnostic options for this rare and not yet officially recognized disease entity. Based on a case report the findings of magnetic resonance imaging (MRI) and ultrasound scanning are presented.

Implications of a genomic search for autophagy-related genes in trypanosomatids.

Autophagy is the process by which cellular components are directed to and degraded in the vacuole or lysosome and has been studied largely in yeasts. We present here an in silico genomic analysis of trypanosomatid autophagy aimed at highlighting similarities and differences with autophagy in other organisms. Less than half of the yeast autophagy-related proteins examined have certain putative orthologues in trypanosomatids. A cytosol-to-vacuole transport system is clearly lacking in these organisms. Other absences are even more unexpected and have implications for our understanding of the molecular mechanisms of autophagy. The results are consistent with taxon-specific addition of components to a core autophagy machinery during evolution.

[The Anaesthesiological Questionnaire for patients in cardiac anaesthesia. Results of a multicenter survey by the scientific working group for cardiac anaesthesia of the German Society for Anaesthesiology and Intensive Care Medicine]. / Der Anästhesiologische Nachbefragungsbogen für Patienten in der Herzanästhesie. Ergebnisse einer Multizentererhebung des wissenschaftlichen Arbeitskreises Kardioanästhesie der Deutschen Gesellschaft für Anästhesiologie und Intensivmedizin.

OBJECTIVE: The Anaesthesiological Questionnaire (ANP) is a self-rating method for the assessment of postoperative complaints and patient satisfaction. The questionnaire was adapted for use in cardiac anaesthesia (ANP-KA). The study was conducted to show the value of ANP-KA as a practicable means of assessing the patient's state after cardiac anaesthesia and for its use in quality assurance. METHODS: A total of 1,688 patients from 19 clinics were included who had exclusively received heart valve surgery, CABG surgery or both operations. They completed the ANP-KA between days 1 and 8 postoperatively. RESULTS: The ANP-KA was completed by 79.1% of the patients without any assistance. The highest incidence rates were reported for a dry mouth/thirst (85.1%) and for pain in the area of surgery (60.2%). Plausible and significant differences in patients' symptoms between the grading for the immediate postoperative period and the current state at filling in the questionnaire were found. Women reported more postoperative complaints than men but no differences were found between male and female patients with regard to satisfaction with anaesthesiological care and convalescence. More complaints were reported after heart valve surgery than after CABG and satisfaction with convalescence was significantly lower after heart valve surgery. The clinics differed with respect to the reported somatic complaints and satisfaction scales. CONCLUSION: The results demonstrate the practicability and validity of the ANP-KA for the assessment of postoperative complaints and patient satisfaction after cardiac surgery.

The expression and intracellular distribution of phosphoglycerate kinase isoenzymes in Trypanosoma cruzi.

In this paper, we report the subcellular distribution of phosphoglycerate kinase (PGK) in epimastigotes of Trypanosoma cruzi. Approximately 80% of the PGK activity was found in the cytosol, 20% in the glycosomes. Western blot analysis suggested that two isoenzymes of 56 and 48 kDa, respectively, are responsible for the glycosomal PGK activity, whereas the cytosolic activity should be attributed to a single PGK of 48 kDa. In analogy to the situation previously reported for PGK in Trypanosoma brucei, these isoenzymes were called PGKA, C and B, respectively. However, in T. cruzi, PGKA seems not to be a minor enzyme like its counterpart in T. brucei. Whereas PGKC behaved as a soluble glycosomal matrix protein, PGKA appeared to be present at the inner surface of the organelle's membrane. After alkaline carbonate treatment, the enzyme remained associated with the particulate fraction of the organelles. Upon solubilization of glycosomes with Triton X-114, PGKA was recovered from the detergent phase, indicating its (partial) hydrophobic character and therefore, a possible hydrophobic interaction with the membrane. The PGKA gene was cloned and sequenced, but the predicted amino-acid sequence did not reveal an obvious clue as to the mechanism by which the enzyme is attached to the glycosomal membrane.

Glycolysis as a target for the design of new anti-trypanosome drugs.

Glycolysis is perceived as a promising target for new drugs against parasitic trypanosomatid protozoa because this pathway plays an essential role in their ATP supply. Trypanosomatid glycolysis is unique in that it is compartmentalized, and many of its enzymes display unique structural and kinetic features. Structure- and catalytic mechanism-based approaches are applied to design compounds that inhibit the glycolytic enzymes of the parasites without affecting the corresponding proteins of the human host. For some trypanosomatid enzymes, potent and selective inhibitors have already been developed that affect only the growth of cultured trypanosomatids, and not mammalian cells.

[Natriuretic peptides: physiological, pathophysiological and clinical aspects]. / Natriuretische Peptide: Physiologische, pathophysiologische und klinische Aspekte.

A milestone was reached in cardiophysiology when in 1981 DeBold demonstrated that the heart functions as an endocrine gland by injecting an extract of atrial muscle into rats, resulting in an induction of natriuresis and a drop in blood pressure. This observation then led to the discovery of a family of related peptides with slightly different amino acid compositions working in concert to achieve the maintenance of sodium and volume homeostasis. The natriuretic peptide family consists of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and Urodilatin (URO) with their tissue-specific distribution including the heart (ANP, BNP), brain (ANP, BNP, CNP), endothelial cells (CNP), and kidney (URO). These peptides were thought to be primarily involved in cardiovascular and renal functions but have now proven to play a role in other physiological systems. In view of their known biological effects, therapeutic efficacy from administration of ANP, BNP or URO might be anticipated, for example in acute renal failure or congestive heart failure. A number of clinical trials suggest that application of these peptides may represent a new pharmacological tool in the treatment or prevention of these diseases, but the clinical benefit still needs to be shown in large controlled studies. In addition to therapeutic options it is possible that plasma concentrations of ANP and BNP could play a role as diagnostic and prognostic markers of cardiac dysfunction.

NMR spectroscopic analysis of the first two steps of the pentose-phosphate pathway elucidates the role of 6-phosphogluconolactonase.

The pentose-phosphate pathway provides reductive power and nucleotide precursors to the cell through oxidative and nonoxidative branches, respectively. 6-Phosphogluconolactonase is the second enzyme of the oxidative branch and catalyzes the hydrolysis of 6-phosphogluconolactones, the products of glucose 6-phosphate oxidation by glucose-6-phosphate dehydrogenase. The role of 6-phosphogluconolactonase was still questionable, because 6-phosphogluconolactones were believed to undergo rapid spontaneous hydrolysis. In this work, nuclear magnetic resonance spectroscopy was used to characterize the chemical scheme and kinetic features of the oxidative branch. We show that 6-phosphogluconolactones have in fact a nonnegligible lifetime and are highly electrophilic compounds. The delta form (1-5) of the lactone is the only product of glucose 6-phosphate oxidation. Subsequently, it leads to the gamma form (1-4) by intramolecular rearrangement. However, only the delta form undergoes spontaneous hydrolysis, the gamma form being a "dead end" of this branch. The delta form is the only substrate for 6-phosphogluconolactonase. Therefore, 6-phosphogluconolactonase activity accelerates hydrolysis of the delta form, thus preventing its conversion into the gamma form. Furthermore, 6-phosphogluconolactonase guards against the accumulation of delta-6-phosphogluconolactone, which may be toxic through its reaction with endogenous cellular nucleophiles. Finally, the difference between activity of human, Trypanosoma brucei, and Plasmodium falciparum 6-phosphogluconolactonases is reported and discussed.

Roles of triosephosphate isomerase and aerobic metabolism in Trypanosoma brucei.

Kinetoplastid protozoa compartmentalize the first seven enzymes of glycolysis and two enzymes of glycerol metabolism in a microbody, the glycosome. While in its mammalian host, Trypanosoma brucei depends entirely on glucose for ATP generation. Under aerobic conditions, most of the glucose is metabolized to pyruvate. Aerobic metabolism depends on the activities of glycosomal triosephosphate isomerase and a mitochondrial glycerophosphate oxidase, and on glycerophosphate<-->dihydroxyacetone phosphate exchange across the glycosomal membrane. Using a combination of genetics and computer modelling, we show that triosephosphate isomerase is probably essential for bloodstream trypanosome survival, but not for the insect-dwelling procyclics, which preferentially use amino acids as an energy source. When the enzyme level decreased to about 15% of that of the wild-type, the growth rate was halved. Below this level, a lethal rise in dihydroxyacetone phosphate was predicted. Expression of cytosolic triosephosphate isomerase inhibited cell growth. Attempts to knockout the trypanosome alternative oxidase genes (which are needed for glycerophosphate oxidase activity) were unsuccessful, but when we lowered the level of the corresponding mRNA by expressing a homologous double-stranded RNA, oxygen consumption was reduced fourfold and the rate of trypanosome growth was halved.

Enzymes of carbohydrate metabolism as potential drug targets.

The potential for chemotherapeutic exploitation of carbohydrate metabolism in the Trypanosomatidae is reviewed. This review is based largely on discussions held at a meeting of the COST B9 Action, entitled 'Bioenergetics of Protozoan Parasites'. The major questions posed were: which enzymes are the best to target; what further information is required to allow their use for rational drug development; what compounds would constitute the best inhibitors and which of the enzymes of the pentose-phosphate pathway are present inside the glycosomes, as well? Only partial answers could be obtained in many cases, but the interactive discussion between the multidisciplinary group of participants, comprising chemists, biochemists and molecular biologists, provided thought-provoking ideas and will help direct future research.

Identification of the factors associated with compliance to therapeutic diets in older adults with end stage renal disease.

OBJECTIVE: To identify theory based factors pertinent to compliance with therapeutic diets. DESIGN: A paper and pencil survey was read to volunteer hemodialysis patients in outpatient dialysis clinics. SUBJECTS: A convenience sample of 276 hemodialysis patients aged 50 years and older who agreed to be interviewed during treatment. STATISTICAL ANALYSIS: Descriptive statistics were used to report responses to all survey questions. The Fisher exact test was used to test associations between the dependent variable, dietary compliance, and independent variables, which included knowledge, perceived severity of illness, attitudes toward compliance, environmental factors, perceived barriers, self-efficacy, and perceived health benefits. Principal Components Analysis determined final scale items. Logistic regression was used to develop a model of independent variables profiling the compliant patient. RESULTS: Subjects were more likely to be compliant if they indicated favorable attitudes toward compliance (P =.0076), a supportive environment (P =.0107), and knowledge about their diet (P =.0014). A logistic regression model of compliance indicated that subjects who followed their special diets were more likely to have higher knowledge (odds ratio [OR] = 1.092, 95% CI = 1.006, 1.186), perceived fewer barriers (OR = 1.094, 95% CI = 0.841, 1.226), being white race (OR = 0.710, 95% CI = 0.399, 1.263), and having gout (OR = 9.349, 95% CI = 1.139, 76.714). APPLICATION: Health professionals should apply these findings in providing dietary education focused on improving not just knowledge, but attitudes and family support. Nutrition education and health promotion applications geared to non-white populations could be particularly important as tools to improve dietary compliance.