The human polyomaviruses KI and WU: virological background and clinical implications

In 2007, two novel polyomaviruses KI and WU were uncovered in the respiratory secretions of children with acute respiratory symptoms. Seroepidemiological studies showed that infection by these viruses is widespread in the human population. Following these findings, different biological specimens and body compartments have been screened by real‐time PCR in the attempt to establish a pathogenetic role for KI polyomavirus (KIPyV) and WU polyomavirus (WUPyV) in human diseases. Although both viruses have been found mainly in respiratory tract samples of immunocompromised patients, a clear causative link with the respiratory disease has not been established. Indeed, the lack of specific clinical or radiological findings, the frequent co‐detection with other respiratory pathogens, the detection in subjects without signs or symptoms of respiratory disease, and the variability of the viral loads measured did not allow drawing a definitive conclusion. Prospective studies carried out on a large sample size including both immunocompromised and immunocompetent patients with and without respiratory symptoms are needed. Standardized quantitative real‐time PCR methods, definition of a clear clinical cutoff value, timing in the collection of respiratory samples, are also crucial to understand the pathogenic role, if any, of KIPyV and WUPyV in human pathology.     

3-T MRI of the biliary tract variations

Purpose

The gallbladder and the biliary tract are structures in close connection with the adjacent organs and may show a number of variations and anomalies. It is therefore important for surgical purposes to know their anatomy and variations in detail. Various methods are used in the imaging of the variations of the biliary tract and its pathologies, including ultrasonography, computed tomography; direct cholangiographic methods like endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography, intravenous cholangiography and T-tube cholangiography, as well as indirect methods like magnetic resonance cholangiopancreatography (MRCP) or cholescintigraphy. The aim of this study is to investigate the frequency of the anatomic variations of the biliary tract using 3-T MRCP and to compare the findings with the data in the literature.

Materials and methods

For the purposes of this study, patients who underwent MRCP at our hospital (Dicle University Hospital) between November 2009 and February 2012 were investigated retrospectively. A total of 590 patients (between 6 and 88 years of age; mean age: 51 ± 9 years) were included in the study. The MRCP imaging was carried out with an magnetic resonance imaging (MRI) device supplied with 3-T magnetic power and by obtaining T2-weighted images through the single-shot fast spin echo technique using the standard body coil. The axial and coronal source images and the reformatted images were evaluated together in terms of the possible anatomic variations.

Results

Among the 590 patients included in the study, of 233 (39.5 %) showed anatomic variations at different levels in the intra- and extrahepatic biliary tracts. Among these variations, a right posterior hepatic duct insertion to the left hepatic duct at the level of the bifurcation has been observed in 71 patients (12.1 %), trifurcation was observed in 30 patients (5.1 %) and insertion into the main hepatic duct at the proximal aspect of the cystic duct was observed in 18 patients (3.1 %). At the level of the cystic duct, medial insertion of the cystic duct was viewed in 58 patients (9.8 %), distal medial insertion was seen in 40 patients (6.8 %), a short cystic duct was detected in 10 patients (1.7 %), pancreatobiliary junction anomaly was viewed in two patients (0.4 %) and duplicate anatomic variations have been observed in 42 patients (7.2 %).

Conclusion

MRCP studies conducted using 3-T MRI devices may reveal similar or greater numbers of variations when compared to the existing MRCP studies in the literature. 3-T MRI shows a couple of variations. Pointing out these anatomical variations before the surgical intervention may prevent possible iatrogenic traumas. Donors with unsuitable variations for liver transplant may be spotted out at an early phase through the MRCP and certain operations with a high morbidity rate may thus be avoided.     

Effect of exchange blood transfusion on oxygen saturation of neonates with severe neonatal jaundice by pulse oximetry

Objective: To determine if there was any difference in SpO2 readings during exchange blood transfusion (EBT).Methods: A prospective cross-sectional study of neonates with severe neonatal jaundice requiring EBT was conducted. Oxygen saturation was recorded before, immediately and 15 minutes after EBT by using a pulse oximeter. Results: This study included 30 neonates with 20 males and 10 females. The age ranged from 1 to 12 days with a mean of (5.4 ± 2.9) days. Pre-EBT SpO2 ranged from 90％ to 98％ with a mean value of (94.3 ± 2.2)％; SpO2 in the end of EBT ranged from 85％ to 99％ with a mean value of (94.1 ± 3.2)％; SpO2 at 15 minutes after EBT ranged from 77％ to 99％ with a mean value of (94.8 ± 4.1)％. There was no significant difference between SpO2 values at onset of EBT and either immediately or 15 minutes after EBT (P=0.770 and 0.422, respectively). SpO2 showed no significant difference between neonates who were infused with blood of different storage times (<24 h or ≥24 h) at the onset of EBT (P=0.584), immediately (P>0.999) and 15 minutes after EBT (P=0.887). Besides, SpO2 values were compariable in neonates with hematocrit <45％ or ≥45％ at the onset of EBT (P=0.284), immediately (P=0.118) and 15 minutes after EBT (P=0.868). Conclusions: EBT does not affect SpO2 in neonates.     

Instant and quantitative epoxidation of styrene under ambient conditions over a nickel(ii)dibenzotetramethyltetraaza[14]annulene complex immobilized on amino-functionalized SBA-15

Nickel(ii)dibenzotetramethyltetraaza[14]annulene complex (Nitmtaa) was synthetized and immobilized on post amino-functionalized SBA-15 (N-SBA-15) to obtain a stable and reusable nanocatalyst named as Nitmtaa@N-SBA-15. Here (3-aminopropyl)triethoxysilane (APTES) was first grafted on the surface SBA-15, then Nitmtaa was added and coordinated on the silica surface via APTES amine groups. The structure and morphology, and thermal stability of the prepared nanocatalyst was investigated using SEM, HR-TEM, BET, FT-IR, powder XRD, and TGA. HR-TEM and XRD results revealed a high dispersion of Nitmtaa on the SBA-15 surface. The catalytic activity of this nanocatalyst was evaluated in the epoxidation of styrene, under ambient conditions, using meta-chloroperoxybenzoic acid (m-CPBA) as the oxygen donor. This nanocatalyst showed an immediate and quantitative epoxidation of styrene with high turn-over-frequency ∼31.58 s⁻¹. Moreover, the superior catalytic activity and high stability of Nitmtaa@N-SBA-15 could be maintained after four successive cycles. A possible reaction mechanism is also proposed.

Immediate and quantitative epoxidation of styrene under ambient conditions catalyzed by new nanocatalyst obtained by immobilizing nickel(ii)dibenzotetramethyltetraaza[14]annulene in amino-functionalized SBA-15.     

Homology modeling in drug discovery: Overview,current applications,and future perspectives

Homology modeling is one of the computational structure prediction methods that are used to determine protein 3D structure from its amino acid sequence. It is considered to be the most accurate of the computational structure prediction methods. It consists of multiple steps that are straightforward and easy to apply. There are many tools and servers that are used for homology modeling. There is no single modeling program or server which is superior in every aspect to others. Since the functionality of the model depends on the quality of the generated protein 3D structure, maximizing the quality of homology modeling is crucial. Homology modeling has many applications in the drug discovery process. Since drugs interact with receptors that consist mainly of proteins, protein 3D structure determination, and thus homology modeling is important in drug discovery. Accordingly, there has been the clarification of protein interactions using 3D structures of proteins that are built with homology modeling. This contributes to the identification of novel drug candidates. Homology modeling plays an important role in making drug discovery faster, easier, cheaper, and more practical. As new modeling methods and combinations are introduced, the scope of its applications widens.     

Disturbed Left Atrial Function is Associated with Paroxysmal Atrial Fibrillation in Hypertension

Background

Hypertension is the most prevalent and modifiable risk factor for atrial fibrillation. The pressure overload in the left atrium induces pathophysiological changes leading to alterations in contractile function and electrical properties.

Objective

In this study our aim was to assess left atrial function in hypertensive patients to determine the association between left atrial function with paroxysmal atrial fibrillation (PAF).

Method

We studied 57 hypertensive patients (age: 53±4 years; left ventricular ejection fraction: 76±6.7%), including 30 consecutive patients with PAF and 30 age-matched control subjects. Left atrial (LA) volumes were measured using the modified Simpson''s biplane method. Three types of LA volume were determined: maximal LA(LAVmax), preatrial contraction LA(LAVpreA) and minimal LA volume(LAVmin). LA emptying functions were calculated. LA total emptying volume = LAVmax−LAVmin and the LA total EF = (LAVmax-LAVmin )/LAVmax, LA passive emptying volume = LAVmax− LAVpreA and the LA passive EF = (LAVmax-LAVpreA)/LAVmax, LA active emptying volume = LAVpreA−LAVmin and LA active EF = (LAVpreA-LAVmin )/LAVpreA.

Results

The hypertensive period is longer in hypertensive group with PAF. LAVmax significantly increased in hypertensive group with PAF when compared to hypertensive group without PAF (p=0.010). LAAEF was significantly decreased in hypertensive group with PAF as compared to hypertensive group without PAF (p=0.020). A'' was decreased in the hypertensive group with PAF when compared to those without PAF (p = 0.044).

Conclusion

Increased LA volume and impaired LA active emptying function was associated with PAF in untreated hypertensive patients. Longer hypertensive period is associated with PAF.     

New inflammatory markers in pre-eclampsia: echocardiographic epicardial fat thickness and neutrophil to lymphocyte ratio

Background: Increased epicardial fat thickness (EFT) has been proposed as a new cardiometabolic risk factor. The neutrophil/lymphocyte ratio (NLR) has predictive and prognostic value in several cardiovascular diseases. The aim of this study was to explore the association between EFT and NLR in patients with pre-eclampsia.

Methods: Hundred and eight pregnant patients with a mean age of 30.6?±?6.3 years were included in the study. Patients were divided into two groups based on the presence of pre-eclampsia. All participants underwent transthoracic echocardiography imaging, and complete blood counts were measured by an automated hematology analyzer. Statistical analysis was performed using the Chi-square, Mann–Whitney U, correlation and logistic regression tests, and receiver operating characteristic (ROC) analysis.

Result: The mean EFT value of the pre-eclampsia group was significantly higher than the control group (6.9?±?0.6 versus 5.6?±?0.6; p?p?Conclusion: Unlike many other inflammatory markers and bioassays, NLR and echocardiographic EFT are inexpensive and readily available biomarkers that may be useful for risk stratification in patients with pre-eclampsia.