A wave packet picture of exciton-exciton annihilation: Molecular dimer dynamics.

The usual view of exciton-exciton annihilation (EEA) processes in molecular aggregates is based on locally excited states of the monomer units. However, the corresponding localized configurations can only be assumed if the system is in a coherent superposition of eigenstates, i.e., a wave packet. We study a molecular dimer and focus on the characterization of EEA by a wave packet motion induced in the system by ultrashort pulse excitation. Here, coherences that appear are destroyed by dissipation processes. We discuss the influence of interband and intraband relaxation on the dynamics. The states that participate in the annihilation process are directly accessible by fifth-order optical two-dimensional spectroscopy. Such spectra are calculated, and spectral features are related to the annihilation process.

Exciton-exciton annihilation in a molecular trimer: Wave packet dynamics and 2D spectroscopy.

We theoretically study the exciton-exciton annihilation (EEA) in a molecular trimer MMM. The system is treated within a model of electronic states, and the coupling to a bath is incorporated using the quantum jump method. Two situations of initial excitation are compared. In the first one, a two-photon process populates configurations M*M*M and MM*M* so that two excitons reside on neighboring monomers M. Then, EEA can immediately proceed. In contrast, if the trimer initially is in the local configuration M*MM*, exciton diffusion must occur before the annihilation process can take place. For the trimer, this excitonic motion takes place on a very short time scale. In both cases, wave packets are prepared which show a different quantum dynamics where the latter depends on the couplings and decay rates. It is documented how fifth-order coherent two-dimensional spectroscopy can be used to directly map the EEA as a function of time.

Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy.

We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dostál et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.

Analysis of Determinants for Suture-mediated Closure Device Failure During EVAR Procedures.

OBJECTIVE: Endovascular aortic repair (EVAR) for elective and emergency infrarenal aortic pathologies is the primary approach for treatment nowadays. During such procedure, the suture-mediated closure device (SMCD) (Perclose ProGlideTM, Abbott Laboratories, Chicago, IL, USA) is commonly used. This study aimed to identify potential contributors for SMCD failure in a patient cohort of elective and emergency EVAR. METHODS: Archived medical records from patients who underwent EVAR for aortic pathologies in elective and emergency setting at the University Hospital Düsseldorf, Germany were included. Patient's co-morbidities, access vessel morphologies and hemostasis-related blood parameters were evaluated on their association with SMCD failure applying different statistical methods. RESULTS: A total of 71 patients (139 femoral accesses) was included. The mean age was 73.5 ± 8.4 years. Overall SMCD failure rate was 4.3%, 4.1% for elective and 5.9% for emergency cases, respectively. Total procedure time was longer for the SMCD failure group (323 ± 117.8 min vs 171 ± 43.7 min). The calcification status of the common femoral artery (CFA), the diameter of the aortic bifurcation, and dual anti-platelet therapy (DAPT) on the medication plan prior to the procedure were associated with SMCD failure. Univariate binary logistic regression analysis nominated several potentially relevant predictors for SMCD failure who underwent subsequent multivariable binary logistic regression analysis. Here, DAPT on the medication plan was identified as being promising in predicting SMCD failure (OR 30.5), while anterior plaque formation in the CFA maintained as only statistically relevant determinant (OR 44.9). CONCLUSIONS: This study confirms the CFA calcification status to be associated with SMCD failure. Although discontinued prior to endovascular treatment, DAPT was also found to be associated with SMCD failure. Our results may advocate to perform obligatory platelet testing prior to EVAR to maximize patient safety.

[Vascular injuries during urologic surgery]. / Gefäßverletzungen während urologischer Operationen.

This review article summarizes the epidemiology of vascular injuries during urologic surgery and discusses intraoperative strategies to control bleedings. Techniques of vascular approaches (arteries and veins) are discussed and tricks for vascular repair are explained. Generally, vascular injuries during urologic surgery are rare. However, hemorrhage due to vascular injury is a common cause of critical morbidity and mortality in the perioperative period. Susceptibility to vascular complications such as oncological debulking and revision surgery increase risk for damage. As vascular injuries range from arrosion to avulsion, treatment is also broad, ranging from vascular suture to open or endovascular repair. Prevention of exsanguination requires visual control to stop the bleeding. The surgeon must act quickly to initiate appropriate repair, aiming for damage control and stabilization of the patient. Planning the surgery and consulting an experienced surgeon are decisive for successful management. Catastrophic bleeding has to be controlled and in the case of arterial injury it is often necessary to reconstitute perfusion. Reconstructions such as vascular anastomoses, patch angioplasty or interposition grafts are the preferred surgical techniques which are influenced by the nature of the injury. Vessels have to be thoroughly prepared before cross clamping to prevent injury by vascular clamps. Veins can often be ligated. Endovascular repair is also a possibility to control the bleeding, but nowadays it is often a definitive therapy method. For example, resuscitative endovascular balloon occlusion is useful to stabilize the patient and then to initiate vascular repair. Depending on the type of surgery performed, different vessels are concerned. Severe bleeding is usually located retroperitoneal affecting the aorta, renovisceral and iliac vessels. Predisposing urologic operations are lymphadenectomy, nephrectomy and (cysto)prostatectomy and also the laparoscopic approach can cause bleeding complications.

Molecular monitoring of inactivation efficiencies of bacteria during pulsed electric field treatment of clinical wastewater.

AIMS: The applicability of an alternative wastewater disinfection concept based on the pulsed electric field (PEF) treatment is tested with molecular biology techniques using clinical wastewaters. METHODS AND RESULTS: Hospital wastewater was treated with the PEF technology. The inactivation efficiencies of bacteria were successfully monitored with real-time polymerase chain reaction (PCR). As the differentiation between living and dead bacterial cells is important for the determination of the disinfection efficiency, propidium monoazide (PMA) was applied. PMA selectively penetrates cells with compromised membranes and intercalates into the DNA inhibiting a subsequent PCR amplification. The rates of reduction were examined for specific pathogens and wastewater populations using PCR-denaturing gradient gel electrophoresis. The results showed that the main part of the bacterial population could be inactivated efficiently with the PEF treatment. Moreover, it was demonstrated that naturally occurring nuclease activities were not affected by the PEF treatment in contrast to a thermal treatment. CONCLUSIONS: The results indicated that the PEF treatment is an appropriate alternative disinfection concept for the treatment of clinical wastewaters and surpass the disadvantages of other disinfection methods. SIGNIFICANCE AND IMPACT OF THE STUDY: With the use of propidium monoazide for live-dead distinction, a new concept could be developed for the evaluation of disinfection methods.

Tick-borne encephalitis in Europe and beyond--the epidemiological situation as of 2007.

This review presents an overview of the developments in the epidemiology of tick-borne encephalitis (TBE) during 2007 in Europe, the Far East and Asia, as well as some comments interpreting the various developments. The recent TBE situation in 29 European and four non-European countries is shown and discussed. The number of registered TBE cases from 1976 to 2007 in 19 European countries with endemic TBE is presented. Although criteria for TBE reporting vary from one country to another and it is necessary to account for unreported cases, an overall increase of TBE incidence during the last 30 years can clearly be established. Besides changes in climate and weather, a number of additional factors are probably responsible for this rise: increased exposition, partly due to socio-economical and political changes, and other factors that are for the most part unknown. In addition, the immunisation coverage in the population of some of the countries is discussed..

[Lyme borreliosis: research gaps and research approaches. Results from an interdisciplinary expert meeting at the Robert Koch Institute]. / Lyme-Borreliose: Forschungsbedarf und Forschungsansätze. Ergebnisse eines interdisziplinären Expertentreffens am Robert Koch-Institut.

Lyme borreliosis is currently the most frequent tick-transmitted zoonosis in the northern hemisphere. Germany and other European countries are regarded as highly endemic areas; therefore the burden of disease and consequently the costs for the health systems are considered to be high. This report summarises the results of an interdisciplinary workshop on Lyme borreliosis which aimed to identify research deficits and to prioritise areas which need to be addressed. Research needs have been recognised for different areas: diagnosis, epidemiology, immunology, clinics, ecology and health services research. Examples of research areas which have priority are the standardisation of diagnostic tests, the development of markers to detect an active infection, the improvement of the epidemiological database and the analysis of the burden of disease.

[Re-evaluation of the risk areas for tick-borne encephalitis in Germany]. / "FSME-risikogebiete in Deutschland müssen neu definiert werden".

In the view of the authors, the present map showing the distribution of the high-risk areas for tick-borne encephalitis is no longer compatible with state of the art information. They therefore call for a re-evaluation of present definitions and a new risk map. Detection of the virus in ticks with the aid of PCR should be given the same weight as an individual clinical case. In future, a differentiation into low-risk, risk and high-risk areas should be avoided.

[Epidemiology of TBE]. / Jetzt stechen sie wieder! In immer mehr Regionen sind Zecken FSME-Träger.

In the period between 1974 and 2003, the incidence of TBE increased appreciably in most European countries. Numerous factors, including climatic changes, biological (ecological) and non-biological factors, have an influence on the epidemiology of TBE. In addition, a greater awareness and better understanding (of the problem), improvements in diagnosis, an increase in travel, political and associated major social changes have had an impact on epidemiological data banks. We shall succeed in turning back the rising tide only by achieving further progress in the field of risk analysis, and redoubling our efforts in the area of active immunisation.

The phagocytosis capacity assay: a new radiometric phagocytosis test for clinical use.

A radiometric technique is described for measuring phagocytosis which does not require separation of extra- and intracellular microorganisms. Following phagocytosis of optimally opsonized yeast cells (Saccharomyces cerevisiae) by mononuclear cells (MNC) or granulocytes, yeast cells remaining extracellular are labeled with [75Se]L-selenomethionine. To measure the phagocytic capacity of the cell population investigated, 1-4 x 10(6) leukocytes are incubated with 5, 10, 20, 30 and 40 x 10(6) yeast cells/ml for testing. Depending on the actual number of phagocytes in the cell populations investigated, different optimal yeast cell concentrations may be determined. Provided measurements are carried out at these optima even moderate effects of therapy can be detected. In a preliminary study of 22 patients with Hodgkin's disease it was shown, that the phagocytic activity of the MNC fraction was higher, but the activity of granulocytes lower, than that of the healthy controls. After combined chemotherapy the above mentioned values returned to normal. This simple, exact method is recommended for clinical use.

The in vitro activity of lectin I from mistletoe (ML I) and its isolated A and B chains on functions of macrophages and polymorphonuclear cells.

We investigated the effects of ML I and its isolated chains, A and B, in regard to selected functions of phagocytes (human granulocytes, paraffin-oil stimulated M phi from guinea pigs). On these cells, ML I has no cytotoxic effect between 10(-14) and 10(-8) (trypan blue exclusion and ethidium bromide exclusion). Over the same concentration range, ML I and B chain diminish the negative surface charge of M phi and agglutinate M phi at concentrations greater than or equal to 2 X 10(-8) M (ML I) and greater than or equal to 3 X 10(-7) M (B chain), respectively. The diminishing of the negative surface charge shows two peaks, indicating the existence of two types of receptors on the M phi surface with different affinities for sugar-binding sites. Moreover, the B chain shows a third peak at higher concentrations (3 X 10(-8) M) that could be inhibited by D-galactose (greater than or equal to 10(-4) M). In comparison, the A chain reduces the surface charge at concentrations over 3 X 10(-7) M, but D-galactose has no effect on this. By means of the agarose droplet test, the spontaneous migration of M phi is inhibited in the sequence ML I much greater than B chain greater than A chain. The phagocytic activity of human leukocytes tested with a radiometric phagocytosis technique reveals an increasing effect only for the B chain; ML I and the A chain have no effect. Perhaps the mechanism of the described activities of ML I and its B chain are comparable with the action of lymphokines activating M phi.

Viral zoonosis from the viewpoint of their epidemiological surveillance: tick-borne encephalitis as a model.

Tick-borne encephalitis (TBE) is a vector borne and, more rarely, a food (milk, milk products) borne disease of humans. For further characterization of the virus activity in natural foci of TBE more than 32,000 unengorged wild ticks were caught in low and high virus active foci in Germany (Mecklenburg-Western Pomerania, Saxony, Brandenburg, Thuringia, Bavaria, Baden-Württemberg, Saarland). The ticks were examined by RT-PCR and Southern blot hybridization as well as by classical virological methods. The dynamics of such natural foci of TBE in the last 35 years were discussed. Also nucleotide sequence data of parts of the virus genome (5'-non coding region) of 16 European and some Far East subtype strains were compared.

Detection of tick-borne encephalitis virus RNA in ticks (Ixodes ricinus) by the polymerase chain reaction.

A polymerase chain reaction for the detection of tick-borne encephalitis virus (TBEV) RNA in ticks was developed. Two pairs of primers for nested PCR were selected from the 5'-NCR and the 5'-terminus of the C protein coding region, which are highly conserved among the TBEV isolates sequenced so far. The sensitivity of the nested PCR was tested by dilution experiments of a TBEV positive brain suspension. The specificity of the PCR products was confirmed by Southern blotting. In a pilot study, 60 homogenates of 7200 ticks (I. ricinus) were examined by PCR. Two homogenates were found positive. The PCR for TBEV RNA appears to be a valuable method to define endemic areas of TBE.

Tick-borne virus diseases of human interest in Europe.

Several human diseases in Europe are caused by viruses transmitted by tick bite. These viruses belong to the genus Flavivirus, and include tick-borne encephalitis virus, Omsk haemorrhagic fever virus, louping ill virus, Powassan virus, Nairovirus (Crimean-Congo haemorrhagic fever virus) and Coltivirus (Eyach virus). All of these viruses cause more or less severe neurological diseases, and some are also responsible for haemorrhagic fever. The epidemiology, clinical picture and methods for diagnosis are detailed in this review. Most of these viral pathogens are classified as Biosafety Level 3 or 4 agents, and therefore some of them have been classified in Categories A-C of potential bioterrorism agents by the Centers for Disease Control and Prevention. Their ability to cause severe disease in man means that these viruses, as well as any clinical samples suspected of containing them, must be handled with specific and stringent precautions.

The influence of selected urinary constituents on the adhesion process of Escherichia coli to human uroepithelial cells.

In the pathogenesis of infectious diseases, great importance is attached to the problem of adhesion of bacteria to cells. In 100 urine specimens from normal test persons, patients with infections of the lower urinary tract, with chronic pyelonephritis and glomerulonephritis were studied. The adhesion of strains of Escherichia coli to human uroepithelial cells depended on the concentration of single urinary factors. While increased concentrations of urea and creatinine favored the adhesion process, a statistically significant negative influence was found with regard to potassium, immunoglobulins and pH value. Considering the multifactorial effects of the urinary constituents, we found in a multivariate comparison that none of the studied physiological features alone exerts a fundamental influence upon adhesion, but in their entirety they determine the environmental conditions for the adhesion of bacteria to cells in the urine.

In vitro phagocytosis by crevicular phagocytes in various forms of periodontitis.

Phagocytes from the gingival crevice fluid (CF-cells) of 11 patients with localized juvenile and post-juvenile periodontitis (LJP/PJP), 14 with rapidly progressive periodontitis (RPP), 11 with adult periodontitis (AP), and 14 controls without periodontal disease were examined. Phagocytic activity in vitro was assessed. Crevicular washings were obtained from healthy sites of controls and diseased sites of patients after completion of the oral hygiene phase (professional and home care). The cells were carefully processed to avoid mechanical damage. The in vitro phagocytosis by uptake of opsonized C. albicans was performed in a moist chamber (30 minutes, 37 degrees C) and examined by light microscopy. CF-cells were differentiated on the basis of their morphological appearance. The majority of cells in crevicular washings were PMNs, some macrophages, and few lymphocytes. Phagocytic activity in patients with LJP/PJP and RPP was significantly decreased in comparison with that from AP and the control group. The decreased percentage of cells phagocytosing opsonized C. albicans was associated with the enhanced adherence of opsonized C. albicans. Moreover cell viability of CF-cells from LJP/PJP sites was significantly reduced. The data from the present study suggest that the in vitro phagocytosis of crevicular phagocytes in juvenile and rapidly progressive periodontitis lesions is diminished.

Survey of the hemagglutinin (HA) cleavage site sequence of H5 and H7 avian influenza viruses: amino acid sequence at the HA cleavage site as a marker of pathogenicity potential.

The deduced amino acid sequence at the hemagglutinin (HA) cleavage site of 76 avian influenza (AI) viruses, subtypes H5 and H7, was determined by reverse transcription-polymerase chain reaction and cycle sequencing techniques to assess pathogenicity. Eighteen of the 76 viruses were isolated in 1993 and 1994 from various sources in the United States. In addition, 34 H5 (4 highly pathogenic [HP] and 30 non-highly pathogenic [non-HP]) and 24 H7 (3 HP and 21 non-HP) repository viruses, isolated between 1927 and 1992, were sequenced and the sequences compared to those in recent isolates. All repository HP H5 and H7 viruses studied had multiple basic amino acids adjacent to the HA cleavage site and most had basic amino acids in excess of the proposed minimum motif B-X-B-R (B = basic amino acids arginine or lysine, X = nonbasic amino acid, R = arginine) that has been associated with high pathogenicity. Of the non-HP viruses studied, 35 of 38 for H5 and 30 of 31 for H7 conformed to the motif B-X-X-R and B-X-R, respectively. Two non-HP H5 viruses had the motif X-X-X-R at the cleavage site and a third had the motif B-X-X-K (K = basic amino acid lysine). One non-HP H7 (A/Pekin robin/CA/30412-5/94) had four basic amino acids (K-R-R-R) adjacent to the cleavage site. Although the Pekin robin isolate did not produce disease in chickens under the conditions of the study it did have the amino acid sequence compatible with that in HP AI viruses and, therefore, is considered potentially HP. This is the first account of an H7 virus that is non-HP in chickens but meets the molecular criterion to be classified as HP.

Influence of membranes on generation of beta 2 M and release of leukocyte lysosomal enzymes.

Normal leukocyte functional capacity was investigated by evaluation of phagocytosis of opsonised yeast cells in a radiometric test system. After incubation with dialysis membranes (different cellulosic membranes, polysulfon membrane (PS), polymethylmetacrylate membrane (PMMN), the phagocytosis index, expressed as percent decrease with respect to initial values without membrane, decreased by 10%-25%. The most pronounced effect was observed with PS, cuprophane, modified cellulose and PMMA. The results are not related to differences in the viability of PMN during the test procedure; dead PMN amounted to about 4-6.5%. A significant increase in beta-NAG and beta-Gluc activities was released in the supernatants of the phagocytosis suspensions. This increase activity can be explained by the phagocytosis of PMN but it was not influenced by membrane contact. There was no influence of membrane contact or phagocytosis activity of PMN on the beta 2 M concentration in the supernatant demonstrating that no in vitro generation during incubation with either membrane exists.