Apropos of a case of pancreatic lymphoepithelial cyst: importance of the preoperative diagnosis by ecoendoscopy.

The case was a 75-year-old female with dyspeptic symptoms of a 2 month duration. There was a polycystic lesion at the level of the uncinate pancreatic process of 44 x 42 x 34 mm on abdominal ultrasound and MRI, which caused a slight dilation of the main pancreatic duct. EUS was performed that identified a multicystic formation of 25x36 mm in the pancreatic body and FNA was performed of the lesion. The cytological analysis identified squamous epithelial cells with lymphoid tissue, which was compatible with a lymphoepithelial cyst, with no evidence of cell atypia or other signs of malignancy. Radiological control and monitoring of the lesion was performed and it has remained stable for 2 years.

Atomistic models of ion and solute transport by the sodium-dependent secondary active transporters.

The recent determination of high-resolution crystal structures of several transporters offers unprecedented insights into the structural mechanisms behind secondary transport. These proteins utilize the facilitated diffusion of the ions down their electrochemical gradients to transport the substrate against its concentration gradient. The structural studies revealed striking similarities in the structural organization of ion and solute binding sites and a well-conserved inverted-repeat topology between proteins from several gene families. In this paper we will overview recent atomistic simulations applied to study the mechanisms of selective binding of ion and substrate in LeuT, Glt, vSGLT and hSERT as well as its consequences for the transporter conformational dynamics. This article is part of a Special Issue entitled: Membrane protein structure and function.

Ab initio potential energy and dipole moment surfaces for CS2: determination of molecular vibrational energies.

The ground state potential energy and dipole moment surfaces for CS2 have been determined at the CASPT2/C:cc-pVTZ,S:aug-cc-pV(T+d)Z level of theory. The potential energy surface has been fit to a sum-of-products form using the neural network method with exponential neurons. A generic interface between neural network potential energy surface fitting and the Heidelberg MCTDH software package is demonstrated. The potential energy surface has also been fit using the potfit procedure in MCTDH. For fits to the low-energy regions of the potential, the neural network method requires fewer parameters than potfit to achieve high accuracy; global fits are comparable between the two methods. Using these potential energy surfaces, the vibrational energies have been computed for the four most abundant CS2 isotopomers. These results are compared to experimental and previous theoretical data. The current potential energy surfaces are shown to accurately reproduce the low-lying vibrational energies within a few wavenumbers. Hence, the potential energy and dipole moments surfaces will be useful for future study on the control of quantum dynamics in CS2.

[Page kidney: subcapsular haematoma and arterial hypertension. A new case report and review of the literature]. / Ri˜ón de page: hematoma subcapsular renal e hipertensión arterial. Presentación de un nuevo caso y revisión de la literatura.

OBJECTIVE: We present the case of a spontaneous subcapsular renal hematoma with increase of the levels of blood pressure in a patient previously normotensive. METHODS: Patient with abdominal pain, spontaneous without previous trauma. CT showed a right subcapsular kidney hematoma. High levels of blood pressure were noticed at the admission in urology. CONCLUSION: Page kidney is a cause of arterial hypertension due to external compression of renal parenchyma. It could be unnoticed as essential hypertension if high suspicion is not taken into account. Nowadays, the main cause of Page kidney is the renal biopsy in the context of kidney transplantation. The treatment is not recommended in the guidelines although the conservative management is proposed as first option.

Right renal infarction: a new case report.

OBJECTIVE: To present a new case of renal infarction. METHODS: We report the case of an 84-year-old woman presenting with right flank colic pain of 24 hours of evolution and past history of acute myocardial infarction four months before. CONCLUSION: Renal infarction is a rare condition; in most of the cases it does not show specific symptoms and usually overlap with other more common urologic procedures, which results in a delay in diagnosis and treatment. The most conclusive imaging tests are i.v contrast CT scan or Doppler ultrasound but definitive diagnosis is achieved by angiography or CT angiography. Treatment is conservative, with parenteral and oral anticoagulation; invasive management is rare.

Molecular dynamics simulations of DNA/PEI complexes: effect of PEI branching and protonation state.

Complexes formed by DNA and polyethylenimine (PEI) are of great research interest because of their application in gene therapy. In this work, we carried out all-atom molecular dynamics simulations to study eight types of DNA/PEI complexes, each of which was formed by one DNA duplex d(CGCGAATTCGCG)(2) and one PEI. We used eight different PEIs with four different degrees of branching and two protonation ratios of amine groups (23% and 46%) in the simulations to investigate how the branching degree and protonation state can affect the binding. We found that 46% protonated PEIs form more stable complexes with DNA, and the binding is achieved mainly through direct interaction between the protonated amine groups on PEI and the electronegative oxygens on the DNA backbone, with some degree of interaction with electronegative groove nitrogens/oxygens. For the 23% protonated PEIs, indirect interaction mediated by one or more water molecules plays an important role in binding. Compared with the protonation state, the degree of branching has a smaller effect on binding, which essentially diminishes at the protonation ratio of 46%. These simulations shed light on the detailed mechanism(s) of PEI binding to DNA, and may facilitate the design of PEI-based gene delivery carriers.

The structural pathway for water permeation through sodium-glucose cotransporters.

Although water permeation across cell membranes occurs through several types of membrane proteins, the only permeation mechanism resolved at atomic scale is that through aquaporins. Crystallization of the Vibrio parahaemolyticus sodium-galactose transporter (vSGLT) allows investigation of putative water permeation pathways through both vSGLT and the homologous human Na-glucose cotransporter (hSGLT1) using computational methods. Grand canonical Monte Carlo and molecular dynamics simulations were used to stably insert water molecules in both proteins, showing the presence of a water-filled pathway composed of ∼100 water molecules. This provides a structural basis for passive water permeation that is difficult to reconcile with the water cotransport hypothesis. Potential-of-mean-force calculations of water going through the crystal structure of vSGLT shows a single barrier of 7.7 kCal mol(-1), in agreement with previously published experimental data for cotransporters of the SGLT family. Electrophysiological and volumetric experiments performed on hSGLT1-expressing Xenopus oocytes showed that the passive permeation pathway exists in different conformational states. In particular, experimental conditions that aim to mimic the conformation of the crystal structure displayed passive water permeability. These results provide groundwork for understanding the structural basis of cotransporter water permeability.

Preliminary study of a new, fully automated system for liquid-based cytology: the NovaPrep® processor system.

OBJECTIVE: To evaluate a fully automated system for liquid-based cytology (LBC): the NovaPrep® Processor System (NPS), which is based on the new concept of double decantation, versus conventional cytology (CC), the gold standard for cytology. STUDY DESIGN: We performed a preliminary comparative study involving 1,129 female patients who underwent sampling for a Pap test; the sample was first smeared for CC and then, using the remaining specimen on the brush, for LBC with the NPS. The performances of CC and NPS were evaluated for accuracy and compared using the gold standard of a combination of one of the two methods of pathological cytology with screening for positive human papilloma virus, quantification of cells (normal and pathological), and improvement in the quality of samples and reading time. RESULTS: The results showed improvement in sensitivity (3.81% for CC vs. 4.52% for NPS) with a specificity superior to 90% for both, a markedly decreased number of unsatisfactory specimens, notably samples containing too many inflamed cells (7.4% for CC vs. 0.5% for NPS), and a shortening of the reading time, which was three times less using NPS. CONCLUSION: This preliminary study showed a gain in sensitivity, a drop in the number of unsatisfactory specimens and a reduction in reading time with NPS. The results achieved using this fully automated LBC procedure are very promising and will hopefully reduce the overall cost of cervical cancer screening in the future.

Weakly bound complexes trapped in quantum matrices: Structure, energetics, and isomer coexistence in (para-H(2))(N)(ortho-D(2))(3) clusters.

The ground state of mixed (para-H(2))(N)(ortho-D(2))(3) clusters of sizes ranging from N=8 to 37 is examined by means of the path integral ground state method. The chemical potential is calculated and reveals that magic numbers are consistent with those found in pure para-H(2) and ortho-D(2) clusters. The structural features of the mixed clusters are examined by analyzing density profiles, one-dimensional Pekeris distribution functions of the (ortho-D(2))(3) subsystem, and by direct visualization of density isosurfaces of the systems. The heavier (ortho-D(2))(3) complex resides in the center of the cluster for the various sizes under consideration. It is found that certain cluster sizes favor either equilateral, or near-linear isosceles (ortho-D(2))(3) configurations, while others show a coexistence between those two triangular geometries.

On the solid- and liquidlike nature of quantum clusters in their ground state.

The ground state of pristine clusters of (paraH(2))(N) and (orthoD(2))(N) of size ranging from N=11 to 55 is examined by means of the variational path integral method. The chemical potential is calculated for two different interaction models and it is shown that the location of magic numbers indeed depends on the chosen interaction potential. Density profiles are calculated and reveal the difference between the two isotopes with regards to shell structure. The magnitude of relative pair distance and position fluctuations is used to asses the rigidity of these finite-size quantum systems. A comparison of generic and specific distance fluctuations as a function of cluster size is proposed as a probe of the appearance of rigidity in the clusters. It is found that smaller (paraH(2))(N) clusters are fluidlike and start to display increased rigidity for clusters of size N> or =26, whereas (orthoD(2))(N) clusters of N=13 and N> or =19 are rigid. Small clusters exhibit structures loosely based on an anti-Mackay icosahedral motif. An anti-Mackay to Mackay transition at N=41-42 is suggested.

[RIGHT VARICOCELE AS FINDING OF RIGHT RENAL MASS]. / VARICOCELE DERECHO COMO PRESENTACIÓN DE MASA RENAL DERECHA.

Abdominal and scrotal ultrasounds were requested and, in order of the findings watched they were complemented with an abdominal contrast enhanced CT scan (CECT). The CETC demonstrated a large right renal tumor sized 12 cm located in the upper pole of the right kidney, in contact with hepatic parenchyma (Figure 1). Renal vein and artery were not affected. Important peritumoral collateral circulation was noticed. Consequently to the large tumor size and extrinsic compression, there was dilatation of right spermatic vein. Both Collateral circulation and right spermatic dilated vein converged in the inguinal duct explaining the presence of right varicocele. The image was 3D reconstructed.

Effect of confinement on DNA, solvent and counterion dynamics in a model biological nanopore.

The application of recent advances in nanopore technology to high-throughput DNA sequencing requires a more detailed understanding of solvent, ion and DNA interactions occurring within these pores. Here we present a combination of atomistic and coarse-grained modeling studies of the dynamics of short single-stranded DNA (ssDNA) homopolymers within the alpha-hemolysin pore, for the two single-stranded homopolymers poly(dA)40 and poly(dC)40. Analysis of atomistic simulations along with the per-residue decomposition of protein-DNA interactions in these simulations gives new insight into the very complex issues that have yet to be fully addressed with detailed MD simulations. We discuss a modification of the solvent properties and ion distribution around DNA within nanopore confinement and put it into the general framework of counterion condensation theory. There is a reasonable agreement in computed properties from our all-atom simulations and the resulting predictions from analytical theories with experimental data, and our equilibrium results here support the conclusions from our previous non-equilibrium Brownian dynamics studies with a recently developed BROMOC protocol that cations are the primary charge carriers through alpha-hemolysin nanopores under an applied voltage in the presence of ssDNA. Clustering analysis led to an identification of distinct conformational states of captured polymer and depth of the current blockade. Therefore, our data suggest that confined polymer may act as a flickering gate, thus contributing to excess noise phenomena. We also discuss the extent of water structuring due to nanopore confinement and the relationship between the conformational dynamics of a captured polymer and the distribution of blocked current.

Lymph node non-Hodgkin's lymphoma incidentally discovered during a nephrectomy for renal cell carcinoma.

We report the case of a left laparoscopic nephroureterectomy with the incidental discovery of a non-Hodgkin's lymphoma in one of the lymph nodes of the renal hilum. A laparoscopic nephroureterectomy was decided on for a 64-year-old man. Renal cell carcinoma in the kidney and one lymph node of the renal hilum with non-Hodgkin's lymphoma was found. Chemotherapy was not started for the lymphoma discovery. There are no signs of relapse after two years of follow up. Coexistence in the same patient is an extremely rare condition. We review the literature about this issue to clarify this association.

Laparoscopic management of right renal angiomyolipoma with involvement of the inferior vena cava: case report and review of the literature.

This article reports the case of a 22-year-old woman with right renal angiomyolipoma (AML) and inferior vena cava thrombus. Laparoscopic right nephrectomy and thrombectomy were performed. To the authors' knowledge there have been only 46 reported cases of renal AML with endovascular extension and this is the first case to be completely removed by a laparoscopic approach. Laparoscopic management of this kind of tumour is feasible in spite of the vascular involvement. The centre's experience and enlargement of the tumour are key points for this approach.

Textural analysis in the diagnosis of benign and malignant breast cells.

OBJECTIVE: To study the discriminatory capacity of textural variables to classify the nuclei of breast tumor cells as benign or malignant, using a statistical approach. STUDY DESIGN: Image analysis techniques were used to automatically segment nuclei of cells obtained by fine needle aspiration and Papanicolaou stained. The sample comprised 95 cases of malignant lesions and 47 cases of benign lesions (approximately 25 nuclei per case), and 27 textural variables were measured. Two methods were used to analyze the data: classification and regression trees (CART) and discriminant analysis. RESULTS: The variance in gray levels was the most decisive variable in the CART analysis, correctly classifying 57% and 97% of benign and malignant cases, respectively. Discriminant analysis yielded the best results, correctly classifying 79% and 85% of benign and malignant cases, respectively. CONCLUSION: The classifier obtained by a statistical approach to the textural analysis of Papanicolaou-stained nuclei did not prove useful for diagnostic discrimination. Staining techniques that are not chromatin specific are highly variable, and other features have proven more effective with this type of staining.

Path integral ground state study of finite-size systems: application to small (parahydrogen)N (N=2-20) clusters.

We use the path integral ground state method to study the energetic and structural properties of small para-H2 clusters of sizes ranging from 2 to 20 molecules. A fourth order formula is used to approximate the short imaginary-time propagator and two interaction potentials are considered. Our results are compared to those of exact basis set calculations and other quantum Monte Carlo methods when available. We find that for all cluster sizes considered, our results show a lower ground state energy than literature values obtained by diffusion Monte Carlo and variational Monte Carlo. For the dimer and trimer, ground state energies are in good agreement with exact results obtained using the discrete variable representation. Structural properties are found to be insensitive to the choice of interaction potential. We explore the use of Pekeris coordinates to analyze the importance of linear arrangement in trimers and for trimers within clusters of larger size.

Intermittent alveolar overdistension for 30 or 240 minutes does not produce acute lung injury in normal pig lung.

BACKGROUND: The objective is to study whether alveolar overdistension can induce acute lung injury in pigs as assessed by analysis of respiratory and histological parameters and inflammatory markers. MATERIALS AND METHODS: Experimental study, using mixed-breed pigs. Animals were assigned to one of the following groups: Control Group (CG) (n = 5), applying mechanical ventilation with tidal volume (Vt) of 10 ml/kg, respiratory rate (RR) of 18 bpm, and FiO2 of 1 for 240 min; High Vt for 30 min (HVt-30) Group (n = 5), applying ventilation with Vt of 50 ml/kg and RR of 8 bpm and FiO2 of 1 for 30 min, followed by ventilation as in the CG for a further 210 min; and HVt-240 Group (n = 5), applying ventilation with Vt of 50 ml/kg, RR of 8 bpm, and FiO2 of 1 for 240 min. Hemodynamic parameters, airway pressures, arterial blood gases, extravascular lung water (EVLW), and cytokines (IL-2, IL-4, IL-6, IL-10, TNF-alpha, and ITF-gamma) in plasma and bronchoalveolar lavage (BAL) were determined. Lungs were fixed with 10% formalin for histological analysis. Results are expressed as mean +/- standard deviation. The ANOVA test was used to compare measurements among the three groups. RESULTS: At 30 min, airway pressures and oxygenation of HVt-30 and HVt-240 groups were higher than those of controls [Pplateau: 39.2 +/- 5.6 and 33.0+/- 5.1 versus 12.2 +/- 1.3 (P < 0.01); PaO2/FiO2: 443.8 +/- 55 and 430.6 +/- 34 versus 194.4 +/- 77 (P < 0.01)]. In HVt-240 group, these parameters were also higher than in the other two groups at the subsequent measurement times. There were no differences among the groups in EVLW values. Cytokines were undetected or negligible in plasma and BAL in all of the groups. The histological analysis showed no changes suggestive of acute lung injury. CONCLUSIONS: In this animal model, ventilation for 4 h with large tidal volume did not cause ventilator-induced lung injury.

Path integral ground state with a fourth-order propagator: application to condensed helium.

Ground state properties of condensed helium are calculated using the path integral ground state (PIGS) method. A fourth-order approximation is used as short (imaginary) time propagator. We compare our results with those obtained with other quantum Monte Carlo (QMC) techniques and different propagators. For this particular application, we find that the fourth-order propagator performs comparably to the pair product approximation, and is far superior to the primitive approximation. Results obtained for the equation of state of condensed helium show that PIGS compares favorably to other QMC methods traditionally utilized for this type of calculation.