Contrast Enhanced CT Versus MRI for Accurate Diagnosis of Wall-thickening Type Gallbladder Cancer

Introduction

Diagnosis of wall-thickening type gallbladder cancer (GBC) is challenging. Computed tomography (CT) and magnetic resonance imaging (MRI) are commonly utilized to evaluate gallbladder wall thickening. However, there is a lack of data comparing the performance of CT and MRI for the detection of wall-thickening type GBC.

Aim

We aim to compare the diagnostic accuracy of CT and MRI in diagnosis of wall-thickening type GBC.

Materials and methods

This prospective study comprised consecutive patients suspected of wall-thickening type GBC who underwent preoperative contrast-enhanced CT and MRI. The final diagnosis was based on the histopathology of the resected gallbladder lesion. Two radiologists independently reviewed the characteristics of gallbladder wall thickening at CT and MRI. The association of CT and MRI findings with histological diagnosis and the interobserver agreement of CT and MRI findings were assessed.

Results

Thirty-three patients (malignancy, 13 and benign, 20) were included. None of the CT findings were significantly associated with GBC. However, at MRI, heterogeneous enhancement, indistinct interface with the liver, and diffusion restriction were significantly associated with malignancy (P = 0.006, <0.001, and 0.005, respectively), and intramural cysts were significantly associated with benign lesions (P = 0.012). For all MRI findings, the interobserver agreement was substantial to perfect (kappa = 0.697-1.000). At CT, the interobserver agreement was substantial to perfect (k = 0.631-1.000).

Conclusion

These findings suggest that MRI may be preferred over CT in patients with suspected wall thickening type GBC. However, larger multicenter studies must confirm our findings.

Theoretical investigation on the solid-liquid phase transition of gallium through free energy analysis

CONTEXT

Gallium, renowned for its notably low melting point and unique property of becoming liquid at room temperature, is a valuable constituent in phase change materials. In this study, we investigate the solid-liquid phase transition of gallium using the modified embedded atom method (MEAM) potential. It addresses the technique to compute the free energy difference between the solid and liquid without using a reference state. We examine various thermodynamic and dynamic properties, including density, specific heat capacity, diffusivity, and radial distribution functions. We compute the coexistence temperature of the solid-liquid phase transitions of gallium from free energy analysis. This information is crucial for understanding the behavior of the material under different pressure conditions and can be valuable for various applications, such as materials processing and high-pressure studies. The analysis, findings, and insights of the present work will be of great significance to the broad scientific and engineering communities in the field of phase transformation of materials.

METHODS

A series of molecular dynamics(MD) simulations were conducted using the LAMMPS software packages. The gallium atoms are modeled using the modified embedded atom method (MEAM) potential. To accurately predict the solid-liquid phase transitions of gallium, we calculated free energy by employing the "constrained λ integration" method, coupled with multiple histogram reweighting (MHR). The solid-liquid coexistence line is determined through the Gibbs-Duhem integration technique.

A Dynamic Water Channel Affects O2 Stability in [FeFe]-Hydrogenases

[FeFe]-hydrogenases are capable of reducing protons at a high rate. However, molecular oxygen (O2 ) induces the degradation of their catalytic cofactor, the H-cluster, which consists of a cubane [4Fe4S] subcluster (4FeH ) and a unique diiron moiety (2FeH ). Previous attempts to prevent O2 -induced damage have focused on enhancing the protein's sieving effect for O2 by blocking the hydrophobic gas channels that connect the protein surface and the 2FeH . In this study, we aimed to block an O2 diffusion pathway and shield 4FeH instead. Molecular dynamics (MD) simulations identified a novel water channel (WH ) surrounding the H-cluster. As this hydrophilic path may be accessible for O2 molecules we applied site-directed mutagenesis targeting amino acids along WH in proximity to 4FeH to block O2 diffusion. Protein film electrochemistry experiments demonstrate increased O2 stabilities for variants G302S and S357T, and MD simulations based on high-resolution crystal structures confirmed an enhanced local sieving effect for O2 in the environment of the 4FeH in both cases. The results strongly suggest that, in wild type proteins, O2 diffuses from the 4FeH to the 2FeH . These results reveal new strategies for improving the O2 stability of [FeFe]-hydrogenases by focusing on the O2 diffusion network near the active site.

Electrolyte under Molybdenum Disulfide Surfaces: Molecular Insights on Structure and Dynamics of Water

Molybdenum disulfide (MoS2) is a two-dimensional (2D) material that offers molecular transport and sieving properties and might be a potential candidate for membrane technologies for energy and environmental applications. To facilitate the separation application, understanding the structural and dynamic properties of water near the substrate-aqueous solution is essential. Employing the molecular dynamics simulation, we investigate the density, local water network at the solid-liquid interface, and water dynamics in aqueous electrolyte solutions with various chloride salts confined in MoS2 nanochannels with different pore sizes and electrolyte concentrations. Our simulation results confirm that the layering of interfacial water at the hydrophilic MoS2 surface and the water density variation depends on the nature of the ions. The simulation results imply a strong attraction of cations to the surface-liquid interfaces, whereas anions are expelled from the surface due to electrostatic interaction. An examination of the dynamical property of water reveals that the confinement effect is more pronounced on water mobility when the pore width is less than 3 nm, and the salt concentration is below 1 M, whereas the electrolyte concentration greater than 1 M, ions predominantly drive the water mobility as compared to confinement one. These simulation results enhance experimental observations and provide molecular insights into the local ordering mechanism that can be crucial in controlling water dynamics in nanofiltration applications.

Sonographic "Cervix Sign": A New Ancillary Sign of Gallbladder Neck Malignancy

Background

The differentiation of benign and malignant gallbladder wall thickening is challenging. The purpose of this study is to evaluate a new sonographic sign, "cervix sign" for differentiation of benign and malignant gallbladder neck thickening.

Methods

This retrospective study comprised consecutive patients with gallbladder neck thickening who underwent sonography between August 2019 and December 2021. The presence of "cervix sign" was assessed by two radiologists independently.

Results

Sixty-five patients had gallbladder neck thickening (28 malignant and 37 benign). The sonographic "cervix sign" was present in 18 (64%) patients with malignant thickening and in only one (2.7%) patient with benign thickening (P = 0.0001). The mean wall thickness was greater, and symmetric wall thickening and liver metastases were more common in malignant thickening with "cervix sign" (without reaching statistical significance). There was substantial agreement (kappa = 0.78) between the two observers for the cervix sign.

Conclusion

Sonographic "cervix sign" is a useful ancillary feature of gallbladder neck cancer.

Gastrointestinal involvement in gallbladder cancer: Computed tomography findings and proposal of a classification system

BACKGROUND

There is relatively scarce data on the computed tomography (CT) detection of gastrointestinal (GI) involvement in gallbladder cancer (GBC). We aim to assess the GI involvement in GBC on CT and propose a CT-based classification.

METHODS

This retrospective study comprized consecutive patients with GBC who underwent contrast-enhanced computed tomography (CECT) for staging between January 2019 and April 2022. Two radiologists evaluated the CT images independently for the morphological type of GBC and the presence of GI involvement. GI involvement was classified into probable involvement, definite involvement and GI fistulization. The incidence of GI involvement and the association of GI involvement with the morphological type of GBC was evaluated. In addition, the inter-observer agreement for GI involvement was assessed.

RESULTS

Over the study period, 260 patients with GBC were evaluated. Forty-three (16.5%) patients had GI involvement. Probable GI involvement, definite GI involvement and GI fistulization were seen in 18 (41.9%), 19 (44.2%) and six (13.9%) patients, respectively. Duodenum was the most common site of involvement (55.8%), followed by hepatic flexure (23.3%), antropyloric region (9.3%) and transverse colon (2.3%). There was no association between GI involvement and morphological type of GBC. There was substantial to near-perfect agreement between the two radiologists for the overall GI involvement (k = 0.790), definite GI involvement (k = 0.815) and GI fistulization (k = 0.943). There was moderate agreement (k = 0.567) for probable GI involvement.

CONCLUSION

GBC frequently involves the GI tract and CT can be used to categorize the GI involvement. However, the proposed CT classification needs validation.

Epigenetic CpG duplex marks probed by an evolved DNA reader via a well-tempered conformational plasticity

5-methylcytosine (mC) and its TET-oxidized derivatives exist in CpG dyads of mammalian DNA and regulate cell fate, but how their individual combinations in the two strands of a CpG act as distinct regulatory signals is poorly understood. Readers that selectively recognize such novel 'CpG duplex marks' could be versatile tools for studying their biological functions, but their design represents an unprecedented selectivity challenge. By mutational studies, NMR relaxation, and MD simulations, we here show that the selectivity of the first designer reader for an oxidized CpG duplex mark hinges on precisely tempered conformational plasticity of the scaffold adopted during directed evolution. Our observations reveal the critical aspect of defined motional features in this novel reader for affinity and specificity in the DNA/protein interaction, providing unexpected prospects for further design progress in this novel area of DNA recognition.

A novel computational predictive biological approach distinguishes Integrin β1 as a salient biomarker for breast cancer chemoresistance

Chemoresistance is a primary cause of breast cancer treatment failure, and protein-protein interactions significantly contribute to chemoresistance during different stages of breast cancer progression. In pursuit of novel biomarkers and relevant protein-protein interactions occurring during the emergence of breast cancer chemoresistance, we used a computational predictive biological (CPB) approach. CPB identified associations of adhesion molecules with proteins connected with different breast cancer proteins associated with chemoresistance. This approach identified an association of Integrin β1 (ITGB1) with chemoresistance and breast cancer stem cell markers. ITGB1 activated the Focal Adhesion Kinase (FAK) pathway promoting invasion, migration, and chemoresistance in breast cancer by upregulating Erk phosphorylation. FAK also activated Wnt/Sox2 signaling, which enhanced self-renewal in breast cancer. Activation of the FAK pathway by ITGB1 represents a novel mechanism linked to breast cancer chemoresistance, which may lead to novel therapies capable of blocking breast cancer progression by intervening in ITGB1-regulated signaling pathways.

Randomized crossover trial of 'Roll-over' technique of abdominal paracentesis versus standard technique in suspected malignant ascites

BACKGROUND

The sensitivity of single abdominal paracentesis for diagnosis of peritoneal carcinomatosis (PC) varies from 40-70%. We hypothesized that rolling-over the patient before paracentesis might improve the cytological yield.

RESEARCH DESIGN AND METHODS

This was a single center pilot study with a randomized cross-over design. We compared the cytological yield of fluid obtained by roll-over technique (ROG) with standard paracentesis (SPG) in suspected PC. In the ROG group, patients were rolled side-to-side thrice, and the paracentesis was done within 1 minute. Each patient served as their own control, and the outcome assessor (cytopathologist) was blinded. The primary objective was to compare the tumor cell positivity between SPG and ROG groups.

RESULTS

Of 71 patients, 62 were analyzed. Of 53 patients with malignancy-related ascites, 39 had PC. Most of the tumor cells were adenocarcinoma (30, 94%) with one patient each having suspicious cytology and one having lymphoma. The sensitivity for diagnosis of PC was (31/39) 79.49% in SPG group and (32/39) 82.05% in ROG group (p = 1.00). The cellularity was similar between both the groups (good cellularity in 58% of SPG and 60% of ROG, p = 1.00).

CONCLUSIONS

Rollover paracentesis did not improve the cytological yield of abdominal paracentesis.

TRIAL REGISTRATION

CTRI/2020/06/025887 and NCT04232384.

Genomic characterization of metastatic castration-resistant prostate cancer patients undergoing PSMA radioligand therapy: A single-center experience

BACKGROUND

Genomic defects in DNA-damage repair (DDR) mechanisms have been proposed to affect the radiosensitivity of prostate cancers. In this study, we intended to evaluate the prevalence of genetic alterations in a cohort of metastatic castration-resistant prostate cancer (mCRPC) patients undergoing radioligand therapy (RLT) with prostate-specific membrane antigen (PSMA)-inhibitors as well as the impact of such mutations on treatment outcomes.

METHODS

Data of consecutive mCRPC patients from 2017 to 2021 who were treated with PSMA-RLT and underwent next-generation sequencing (NGS) were collected and analyzed for response and survival outcomes.

RESULTS

In 95 patients of mCRPC treated with PSMA-RLT, 15 patients (median age: 66 years, range: 50-73 years; [¹⁷⁷ Lu]Lu-PSMA-617, n = 12; [²²⁵ Ac]Ac-PSMA-617, n = 3) underwent NGS. The median progression-free survival (PFS) of this cohort was 3 months (95% confidence interval: 1.6-4.4 months). On NGS, 21 genetic alterations were reported in 10/15 (67%) patients, of which 13 were DDR-associated alterations involving the genes: ATM (n = 3), BRCA2 (n = 3), TP53 (n = 2), PTEN (n = 2), FANCD2 (n = 1), FANCM (n = 1), and NBN (n = 1). Overall, 5/15 (33%) patients harbored six pathogenic variants (BRCA2, n = 2; ATM, n = 1; TP53, n = 1; PTEN, n = 2). No significant difference was noted for the biochemical response, radiological response, PFS, and overall survival between the patients with and without genetic alterations.

CONCLUSIONS

Patients of mCRPC undergoing PSMA-RLT were frequently seen to harbor DDR-associated aberrations, albeit with no significant impact on treatment outcomes. Large prospective trials comparing PSMA-RLT-related outcomes in DDR-deficient and -proficient patients are required to bring out the differences, if any, in a more observable manner.

Synthetic Monosaccharide Channels: Size-Selective Transmembrane Transport of Glucose and Fructose Mediated by Porphyrin Boxes

Here we report synthetic monosaccharide channels built with shape-persistent organic cages, porphyrin boxes (PBs), that allow facile transmembrane transport of glucose and fructose through their windows. PBs show a much higher transport rate for glucose and fructose over disaccharides such as sucrose, as evidenced by intravesicular enzyme assays and molecular dynamics simulations. The transport rate can be modulated by changing the length of the alkyl chains decorating the cage windows. Insertion of a linear pillar ligand into the cavity of PBs blocks the monosaccharide transport. In vitro cell experiment shows that PBs transport glucose across the living-cell membrane and enhance cell viability when the natural glucose transporter GLUT1 is blocked. Time-dependent live-cell imaging and MTT assays confirm the cyto-compatibility of PBs. The monosaccharide-selective transport ability of PBs is reminiscent of natural glucose transporters (GLUTs), which are crucial for numerous biological functions.

Increasing the O2 Resistance of the [FeFe]-Hydrogenase CbA5H through Enhanced Protein Flexibility

The high turnover rates of [FeFe]-hydrogenases under mild conditions and at low overpotentials provide a natural blueprint for the design of hydrogen catalysts. However, the unique active site (H-cluster) degrades upon contact with oxygen. The [FeFe]-hydrogenase fromClostridium beijerinckii (CbA5H) is characterized by the flexibility of its protein structure, which allows a conserved cysteine to coordinate to the active site under oxidative conditions. Thereby, intrinsic cofactor degradation induced by dioxygen is minimized. However, the protection from O₂ is only partial, and the activity of the enzyme decreases upon each exposure to O₂. By using site-directed mutagenesis in combination with electrochemistry, ATR-FTIR spectroscopy, and molecular dynamics simulations, we show that the kinetics of the conversion between the oxygen-protected inactive state (cysteine-bound) and the oxygen-sensitive active state can be accelerated by replacing a surface residue that is very distant from the active site. This sole exchange of methionine for a glutamate residue leads to an increased resistance of the hydrogenase to dioxygen. With our study, we aim to understand how local modifications of the protein structure can have a crucial impact on protein dynamics and how they can control the reactivity of inorganic active sites through outer sphere effects.

Progressing Towards a Human-Centric Approach in Cancer Research

Despite the advancement in research methodologies and technologies for cancer research, there is a high rate of anti-cancer drug attrition. In this review, we discuss different conventional and modern approaches in cancer research and how human-centric models can improve on the voids conferred by more traditional animal-centric models, thereby offering a more reliable platform for drug discovery. Advanced three-dimensional cell culture methodologies, along with in silico computational analysis form the core of human-centric cancer research. This can provide a holistic understanding of the research problems and help design specific and accurate experiments that could lead to the development of better cancer therapeutics. Here, we propose a new human-centric research roadmap that promises to provide a better platform for cancer research and drug discovery.

Real-World Breast Cancer Patient Follow-Up Practices by Medical Oncologists in India—A Survey Report

Background  In India, breast cancer patients' post-treatment follow-up practices are not known. We did this survey to understand how the breast cancer patients are followed-up and tried to explore the challenges associated with it.

Methods  We conducted a survey-based study among Indian oncologists. Seven questions were framed pertaining to follow-up practices. Answers were provided in the form of multiple options. Google forms platform was used. Survey was circulated through social media apps and through mail. We sought suggestions and opinions to address the challenges from participants.

Results  A total of 158 medical oncologists responded to this survey. 10% were not aware that only history and clinical examination are the scientific recommendations for follow-up. Ninety percent of the medical oncologists felt clinical breast examination as an uncomfortable practice for patients and physicians and 39% ordered a chest X-ray and an ultrasound abdomen. Annual mammogram was ordered by 83%, and blood investigations were recommended by 14% routinely. The majority (49.6%) felt that the absence of a female attendant, physician and patient factors were responsible for nonadherence to clinical breast examination. The DEXA scan was recommended by 84 (53%) medical oncologists regularly for patients on aromatase inhibitors, while 23 (14%) did not recommend it.

Conclusion  There is a disparity between scientific recommendations and real-world follow-up practices. A large number of medical oncologists relied on chest X-ray and ultrasound abdomen. There is an unmet need to address this issue.

The CTPase activity of ParB determines the size and dynamics of prokaryotic DNA partition complexes

ParB-like CTPases mediate the segregation of bacterial chromosomes and low-copy number plasmids. They act as DNA-sliding clamps that are loaded at parS motifs in the centromere of target DNA molecules and spread laterally to form large nucleoprotein complexes serving as docking points for the DNA segregation machinery. Here, we solve crystal structures of ParB in the pre- and post-hydrolysis state and illuminate the catalytic mechanism of nucleotide hydrolysis. Moreover, we identify conformational changes that underlie the CTP- and parS-dependent closure of ParB clamps. The study of CTPase-deficient ParB variants reveals that CTP hydrolysis serves to limit the sliding time of ParB clamps and thus drives the establishment of a well-defined ParB diffusion gradient across the centromere whose dynamics are critical for DNA segregation. These findings clarify the role of the ParB CTPase cycle in partition complex assembly and function and thus advance our understanding of this prototypic CTP-dependent molecular switch.

Spectrally Resolved Estimation of Water Entropy in the Active Site of Human Carbonic Anhydrase II

A major challenge in understanding ligand binding to biomacromolecules lies in dissecting the underlying thermodynamic driving forces at the atomic level. Quantifying the contributions of water molecules is often especially demanding, although they can play important roles in biomolecular recognition and binding processes. One example is human carbonic anhydrase II, whose active site harbors a conserved network of structural water molecules that are essential for enzymatic catalysis. Inhibitor binding disrupts this water network and changes the hydrogen-bonding patterns in the active site. Here, we use atomistic molecular dynamics simulations to compute the absolute entropy of the individual water molecules confined in the active site of hCAII using a spectrally resolved estimation (SRE) approach. The entropy decrease of water molecules that remain in the active site upon binding of a dorzolamide inhibitor is caused by changes in hydrogen bonding and stiffening of the hydrogen-bonding network. Overall, this entropy decrease is overcompensated by the gain due to the release of three water molecules from the active site upon inhibitor binding. The spectral density calculations enable the assignment of the changes to certain vibrational modes. In addition, the range of applicability of the SRE approximation is systematically explored by exploiting the gradually changing degree of immobilization of water molecules as a function of the distance to a phospholipid bilayer surface, which defines an "entropy ruler". These results demonstrate the applicability of SRE to biomolecular solvation, and we expect it to become a useful method for entropy calculations in biomolecular systems.

'Rollover' abdominal paracentesis versus standard technique: protocol of a crossover randomized comparative trial

The sensitivity of single abdominal paracentesis for diagnosis of peritoneal carcinomatosis in patients with malignant ascites is 40-70%. Tumor cells shed from the peritoneum settle preferentially in certain recesses of the peritoneum. We aim to compare the standard technique of abdominal paracentesis versus a rollover technique in a randomized crossover study to assess the cytological yield in patients suspected to have peritoneal carcinomatosis. Each patient will serve as their own control and the outcome assessor (cytopathologist) will be blinded to the method of paracentesis performed. The primary objective will be to compare the tumor cell positivity between the standard paracentesis group and the rollover group among enrolled patients. Clinical Trial registration: CTRI/2020/06/025887 and NCT04232384.

Docetaxel-Induced Interstitial Pneumonitis Detected on 68Ga-PSMA PET/CT

ABSTRACT

68Ga-PSMA PET/CT is a commonly performed procedure in the staging of intermediate- and high-risk prostate cancer after biochemical recurrence. Uptake of 68Ga-PSMA in benign conditions is also reported in the literature. Docetaxel is the mainstay of treatment in high-volume hormone-sensitive prostate cancer and castration-resistant prostate cancer. The major treatment-emergent adverse drug reactions attributed to docetaxel include myelosuppression, alopecia, and asthenia. Interstitial pneumonitis is seen in less than 2% of docetaxel-treated patients. We present a case of metastatic castration-resistant prostate cancer, wherein docetaxel-induced interstitial pneumonitis was detected on 68Ga-PSMA PET/CT, after docetaxel treatment.

Diffuse large B-cell lymphoma: An institutional analysis

Introduction:

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin's lymphoma. We conducted a retrospective study to analyze the clinicopathological characteristics, cell of origin, response to therapy, and the outcome of patients with DLBCL.

Materials and Methods:

This was a retrospective study which included all patients with DLBCL registered at our center, between May 1, 2013, and July 31, 2015. The data regarding demography, clinical presentation, histopathology, stage, prognostic index, treatment, and treatment-related outcome were collected from prospectively maintained clinical case records of the patients.

Results:

In the study, we included 267 patients. The median age is 49 (20–81) years with male: female ratio of 2:1. B symptoms were seen in 124 (45%) of patients. Early Stages (I and II) were seen in 130 (52%) patients, while advanced Stages (III and 1V) were seen in 119 (48%) patients. Bulky disease (>7.5 cm) was seen in 30% of cases, and bone marrow was involved in 12%. Extranodal involvement is present in 35% of cases. Cell of origin data was available in 160 (60%) of cases, of which 88 (55%) were germinal center and 72 (45%) were activated B cell in origin. The distribution according to the international prognostic index (IPI) was as follows: low risk 40%, intermediate risk 45%, and high risk in 15%. Rituximab was used in 45% of cases. The overall response rate was 84% with a complete response (CR) rate of 70.5%. The CR rates were better with RCHOP compared with CHOP (77% vs. 61.5%, P = 0.001) and good-risk IPI (83.3% vs. 65.2%, P < 0.001) compared with intermediate- and high-risk IPI. Median follow-up period was 24 months, and 2-year event-free survival (EFS) was 70%. The presence of B symptoms, high IPI, failure to attain CR, poor PS, and nonrituximab-based chemotherapy were significantly associated with lower EFS.

Conclusions:

This is the first study from India, which investigated the impact of chemotherapy with or without rituximab in context of cell of origin. Adding rituximab to CHOP showed better response rate and EFS irrespective of cell of origin.

The Active Site of a Prototypical "Rigid" Drug Target is Marked by Extensive Conformational Dynamics

Drug discovery, in particular optimization of candidates using medicinal chemistry, is generally guided by structural biology. However, for optimizing binding kinetics, relevant for efficacy and off-target effects, information on protein motion is important. Herein, we demonstrate for the prototypical textbook example of an allegedly "rigid protein" that substantial active-site dynamics have generally remained unrecognized, despite thousands of medicinal-chemistry studies on this model over decades. Comparing cryogenic X-ray structures, solid-state NMR on micro-crystalline protein at room temperature, and solution NMR structure and dynamics, supported by MD simulations, we show that under physiologically relevant conditions the pocket is in fact shaped by pronounced open/close conformational-exchange dynamics. The study, which is of general significance for pharmacological research, evinces a generic pitfall in drug discovery routines.

Evaluation of Pulmonary Infiltrate in Febrile Neutropenic Patients of Hematologic Malignancies

Background: Pulmonary infection is the major risk during neutropenia induced by chemotherapy as well as stem cell transplantation. In spite of potent new-generation antifungal and broad-spectrum antibiotics, one-third of patients usually die from infectious complications. Early diagnosis and prompt administration of appropriate therapy improve the survival. Materials and Methods: We prospectively carried out the study to identify the infectious etiology of pulmonary infiltrates in febrile neutropenia patients by imaging and bronchoscopy. Bacterial culture, fungal culture, galactomannan and molecular diagnosis for pneumocystis, and other infectious agent were carried out in the bronchoalveolar lavage (BAL) fluid and blood. Results: A total of 27 patients were evaluated. Half of the patients belonged to acute leukemia (46%). We had a diagnostic yield of 65% with the most common isolates being Gram-negative bacteria and Aspergillus species. Conclusion: Gram-negative organisms were the predominant infectious agents of pulmonary infection. Our finding emphasizes the importance of BAL in evaluating pulmonary infiltrates in neutropenic patients with hematological malignancies.

Prevalence of Generalized Anxiety Disorder and its effect on Daily Living in the Rural Community of Rajshahi

This cross-sectional type of descriptive study was conducted in three villages of Puthia Upazila under Rajshahi district to find out the prevalence of Generalized Anxiety Disorder (GAD) and its effect on their daily living. A total of 876 adult people of aged 18 years and above, were selected purposively. Data were collected by face to face interview with the help of a semi-structured questionnaire which contained Hamilton’s 7-point anxiety scale. Out of 876 respondents, 80% had GAD, where mild, moderate and severe GAD being 42.5%, 31.8% and 5.7% respectively. GAD was found to be more frequently associated in the 3rd and 5th decades of life, which constituted 27% and 12.9% respectively (p < 0.001). Having GAD, females have more ability to cope with daily living than males, though GAD was not found to be associated with sex (p >0.05). Illiterate and primary level educated respondents were more often associated with GAD (40.4 and 25% respectively) than the SSC and higher level educated people (p < 0.001). Businessmen were found to be significantly associated with GAD (29.7%) than the other occupations (p < 0.001). Poor people tend to be associated with GAD significantly more than the middle class and the rich (p < 0.01). Widow(er) and married and living together were likely to have GAD than the single or divorced or separated (p < 0.001). Activities of daily living gradually becoming more difficult when intensity of anxiety status increased which is statistically significant (p<0.001).The association between sex and problem facing in everyday life shows that over 40% of the females did not have any difficulty in dealing with problem situation as compared to only 25.8% of the males, while nearly half (48.6%) of males had quite difficulty in dealing with a problem as compared to 37.3% in females (p < 0.001). The present study concluded that majority rural adult people (4 in every five) suffer from generalized anxiety disorder (GAD). The ability of coping with a problem is higher in females than the males. This study might be the basis for further in depth study in this regard.TAJ 2014; 27(1): 14-23

Effect of confinement on the solid-liquid coexistence of Lennard-Jones fluid

The solid-liquid coexistence of a Lennard-Jones fluid confined in slit pores of variable pore size, H, is studied using molecular dynamics simulations. Three-stage pseudo-supercritical transformation path of Grochola [J. Chem. Phys. 120(5), 2122 (2004)] and multiple histogram reweighting are employed for the confined system, for various pore sizes ranging from 20 to 5 molecular diameters, to compute the solid-liquid coexistence. The Gibbs free energy difference is evaluated using thermodynamic integration method by connecting solid-liquid phases under confinement via one or more intermediate states without any first order phase transition among them. Thermodynamic melting temperature is found to oscillate with wall separation, which is in agreement with the behavior seen for kinetic melting temperature evaluated in an earlier study. However, thermodynamic melting temperature for almost all wall separations is higher than the bulk case, which is contrary to the behavior seen for the kinetic melting temperature. The oscillation founds to decay at around H = 12, and beyond that pore size dependency of the shift in melting point is well represented by the Gibbs-Thompson equation.

Use of Induced sputum to determine the prevalence of Pneumocystis jirovecii in immunocompromised children with pneumonia

BACKGROUND

Information on prevalence of Pneumocystis jirovecii pneumonia (PCP) in immunocompromised children with pneumonia in Southeast Asia is limited.

METHODS

Immunocompromised children hospitalized with radiographic pneumonia were investigated for PCP by testing induced sputum by using polymerase chain reaction (PCR).

RESULTS

Ninety-four immunocompromised children (mean age 74.5 ± 43.7 months, boys 69) with pneumonia were investigated for PCP. Underlying disease included solid tumors and hematological malignancy in 57, HIV infection in 14, primary immune deficiency in 11 and other immune deficiency disorders in 12 children. PCR could detect P. jirovecii in 14 children. Prevalence of PCP in HIV-infected children was 43% (6 of 14), renal disease on immunosuppressants 45% (4 of 9), primary immune deficiency 19% (2 of 11) and malignancies on chemotherapy 4% (2 of 57). Three of 14 children died from PCP.

CONCLUSIONS

PCP is responsible for pneumonia in 14% of children with underlying immunocompromised state; PCR on induced sputum improves diagnosis.

Poly(3-methylthiophene)/graphene composite: in-situ synthesis and its electrochemical characterization

Poly(3-methylthiophene)/Graphene composites (G-PMT) and poly(3-methylthiophene) (PMT) were synthesized by in-situ chemical oxidative polymerization and investigated as electrode material for supercapacitors. The interaction between graphene and polymer chains was characterized by Fourier Transform Infrared (FTIR) spectroscopy. The morphology of the nanocomposites was characterized by Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (TEM). The thermal stability of the composite and the polymer was studied by Thermogravimetric Analysis (TGA) which shows G-PMT has higher thermal stability than PMT. The electrochemical properties were investigated by Cyclic Voltammetry (CV), Cyclic Charging-discharging tests (CC) and Electrochemical Impedance Spectroscopy (EIS) in a three-electrode system. G-PMT resulted in higher specific capacitance of 240 F/g. The specific capacitance retention after 500 cycles on G-PMT was also higher compared with PMT. These results indicate that G-PMT has good electrochemical performance than PMT hence it is useful for the making of electrode in supercapacitor application.

Doping effect of polyaniline/MWCNT composites on capacitance and cyclic stability of supercapacitors

Polyaniline doped by Zn2+ ions was synthesized as nanocomposites with multiwalled carbon nanotubes (MWCNT) by in-situ oxidative polymerization and investigated as electrode material for supercapacitors. The uniform coating of polyaniline on MWCNT was characterized by field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The effect of Zn2+ ions on nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy. The electrochemical performances were investigated by cyclic voltammetry (CV), constant current charging/discharging cyclic test (CC) and electrochemical impedance spectroscopy (EIS) using a three-electrode system. The doped polyaniline composites show higher specific capacitance and better cyclic stability.

Stem Cell Experiments and Initial Clinical Trial of Cellular Cardiomyoplasty

Growing myocardial cells from human stem cells and stem cell transplantation to repair injured myocardium are new frontiers in cardiovascular research. The 1st stage of this study was conducted to determine whether transplantation of autologous bone marrow stem cells into infarcted myocardium of sheep could differentiate into beating cardiomyocytes. The 2nd stage was to demonstrate transdifferentiation of human bone marrow mesenchymal stem cells to precursor cardiomyocytes in vitro, using a novel conditioning medium. In the 3rd stage, a clinical trial of stem cell implantation in patients with severe myocardial dysfunction involved injection of peripheral blood-derived endothelial precursor cells in 11 patients and autologous bone marrow mononuclear cells in 29. A marginal improvement in myocardial function was noted at 3 months (mean increase in ejection fraction, 6% ±1%), although it plateaued at 6 months. The trial proved to be safe because there was no procedure-related mortality. There is growing optimism that stem cell therapy may delay heart transplantation.

Effect of modified MWCNT and polyphosphazene elastomer on the properties of PES/LCP blend system

PES/LCP/MWCNT nanocomposites were prepared through melt blending and the effect of Polyphosphazene elastomer as a compatibilizer was investigated. Fourier Transform Infrared Spectra (FTIR) exhibited that Carbon nanotubes (CNT's) were linked with PES. Field Emission Scanning Electron Microscopy (FESEM) micrographs highlighted the dispersion of CNT throughout the matrix and formation of network structure. Rheological analysis revealed the extent of interfacial adhesion. Thermal properties were characterized by Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). A remarkable increase in the magnitude of storage modulus (E') with the addition of MWCNTs was observed through Dynamic mechanical Thermal analysis (DMTA). Crystallinity of the concerned composites was assessed through X-Ray Diffraction (XRD) study. Tensile strength was observed to increase with increasing CNT content, whereas, % of elongation at break was found to decrease. But, in case of polyphosphazene-aided nanocomposite, % of elongation at break was found to increase reflecting the flexible behaviour of the composite.

Preparation and characterization of poly(methyl methacrylate)/multi-walled carbon nanotube composites

This paper focuses on the preparation and characterization of Poly(methyl methacrylate)/multi-walled carbon nanotube composites through ex-situ and in-situ processes. The extent of dispersion and fracture morphology was studied by TEM, AFM, SEM and FESEM. The increase in conductivity at percolated loading of 2.91 wt% was more for in-situ prepared PMMA/MWNTs nanocomposite as compared to ex-situ prepared nanocomposites. The dielectric constant of pure PMMA was increased from 5 to 72 in the ex-situ prepared PMMA/MWNTs nanocomposites with 4.76 wt% of MWNTs loading. Moreover, for the ex-situ nanocomposites containing 2.91 wt% of MWNTs, the dielectric constant was 15, but in-situ prepared PMMA/MWNTs nanocomposite showed two times increase at same loading of 2.91 wt% of MWNTs. Dielectric constant of PMMA/MWNTs nanocomposites loaded with (< 4.76 wt%) of MWNTs remained almost constant with frequency. Dynamic mechanical analysis showed remarkable increase in storage modulus, especially at higher temperatures with 4.76 wt% loading of carbon nanotubes as compared to pure PMMA. The presence of additional peak before T(g) indicated that CNTs could be used to wake up secondary relaxations, which were inactive in pure PMMA. Thermogravimetric analysis (TGA) showed that thermal stability of PMMA/MWNTs nanocomposites increased by 45 degrees C (in N2) and 27 degrees C (in air) at 4.76 wt% of MWNTs as compared to the pure PMMA.

Multi-walled carbon nanotubes/polymer composites in absence and presence of acrylic elastomer (ACM)

Polyetherimide/Multiwall carbon nanotube (MWNTs) nanocomposites containing as-received and modified (COOH-MWNT) carbon nanotubes were prepared through melt process in extruder and then compression molded. Thermal properties of the composites were characterized by thermo-gravimetric analysis (TGA). Field emission scanning electron microscopy (FESEM) images showed that the MWNTs were well dispersed and formed an intimate contact with the polymer matrix without any agglomeration. However the incorporation of modified carbon nanotubes formed fascinating, highly crosslinked, and compact network structure throughout the polymer matrix. This showed the increased adhesion of PEI with modified MWNTs. Scanning electron microscopy (SEM) also showed high degree of dispersion of modified MWNTs along with broken ends. Dynamic mechanical analysis (DMA) results showed a marginal increase in storage modulus (E') and glass transition temperature (T(g)) with the addition of MWNTs. Increase in tensile strength and impact strength of composites confirmed the use the MWNTs as possible reinforcement agent. Both thermal and electrical conductivity of composites increased, but effect is more pronounced on modification due to formation of network of carbon nanotubes. Addition of acrylic elastomer to developed PEI/MWNTs (modified) nanocomposites resulted in the further increase in thermal and electrical properties due to the formation of additional bond between MWNTs and acrylic elastomers at the interface. All the results presented are well corroborated by SEM and FESEM studies.

Synergistic effect of nanoclay and EPR-g-MA on the properties of nylon6/EPR blends

The effect of EPR-g-MA, nanoclay and a combination of the two on phase morphology and properties of (70/30 w/w) nylon6/EPR blends prepared by melt processing technique has been studied. We found that the number average domain diameter (D(n)) of the dispersed EPR phase in the blend decreased in presence of EPR-g-MA, and clay. This observation indicated that nanoclay could be used as an effective compatibilizer in nylon6/EPR blend. X-ray diffraction study and TEM analysis of the blend/clay nanocomposites revealed the delaminated clay morphology and preferential location of the exfoliated clay platelets in nylon6 phase. Thus, selective dispersion of the clay platelets with delaminated morphology in the matrix phase acted as the barrier and thereby prevented the coalescence of dispersed EPR domains during melt processing. However, addition of nanoclay in the blend did not improve the impact property of the blend. Interestingly, the impact strength of the nylon6/EPR/EPR-g-MA/clay blend was much higher than the nylon6/EPR/EPR-g-MA and nylon6/EPR/clay blends at certain compositions with comparable D(n) values. This could be explained by assuming the presence of delaminated clay platelets at the interface, which were stiffer than the polymers. Hence, the bending energy of the interfaces was high.

Curcumin (diferuloylmethane), a singlet oxygen ((1)O(2)) quencher

Curcumin (diferuloylmethane) is a major component of food flavoring turmeric (Curcuma longa), and has been reported to be anticarcinogenic and anti-inflammatory. Although curcumin was shown to have antioxidant properties, its exact antioxidant nature has not been fully investigated. In this report we have investigated the possible antioxidant properties of curcumin using EPR spectroscopic techniques. Curcumin was found to inhibit the (1)O(2)-dependent 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) formation in a dose-dependent manner. (1)O(2) was produced in a photosensitizing system using rose bengal as sensitizer, and was detected as TEMP-(1)O(2) adducts by electron paramagnetic resonance (EPR) spectroscopic techniques using TEMP as a spin-trap. Curcumin at 2.75 microM caused 50% inhibition of TEMP-(1)O(2) adduct formation. However, curcumin only marginally inhibited (24% maximum at 80 microM) reduction of ferricytochrome c in a xanthine-xanthine oxidase system demonstrating that it is not an effective superoxide radical scavenger. Additionally, there was minor inhibition of DMPO-OH adduct formation by curcumin (solubilized in ethanol) when an ethanol control was included in the EPR spin-trapping study, suggesting that curcumin may not be an effective hydroxyl radical scavenger. Together these data demonstrate that curcumin is able only to effectively quench singlet oxygen at very low concentration in aqueous systems.

Idiopathic hypertrophic cranial pachymeningitis

Idiopathic hypertrophic cranial pachymeningitis is a rare form of fibrosing chronic inflammatory process of unknown etiology, which causes thickening of the intracranial dura mater. We present four patients with hypertrophic cranial pachymeningitis who presented with chronic headache and cranial nerve palsies. The diagnosis of idiopathic hypertrophic cranial pachymeningitis was based on neuroimaging findings of thickened enhancing dura, exclusion of known causes and histopathologic findings compatible with nonspecific inflammation in the meningeal biopsies. Corticosteroid therapy was effective in all cases in inducing a complete or partial remission of the neurologic symptoms and signs. We describe the clinical, radiological and pathological features of idiopathic hypertrophic cranial pachymeningitis and discuss the relationship of this entity with other inflammatory fibrosclerotic disorders to explain the pathogenesis. A high index of suspicion, prompt confirmation of the diagnosis by meningeal biopsy, and early institution and long-term maintenance of steroid therapy may help to prevent irreversible neurologic sequelae, especially blindness.

Thioredoxin, a singlet oxygen quencher and hydroxyl radical scavenger: redox independent functions

Thioredoxin is a ubiquitous small protein known to protect cells and tissues against oxidative stress. However, its exact antioxidant nature has not been elucidated. In this report, we present evidence that human thioredoxin is a powerful singlet oxygen quencher and hydroxyl radical scavenger. Human thioredoxin at 3 microM caused 50% inhibition of TEMP-(1)O(2) (TEMPO) adduct formation in a photolysis EPR study. In contrast, Escherichia coli thioredoxin caused 50% inhibition of TEMPO formation at 80 microM. Both E. coli thioredoxin and human thioredoxin inhibited (*)OH dependent DMPO-OH formation as demonstrated by EPR spectrometry. The quenching of (1)O(2) or scavenging of (*)OH was not dependent upon the redox state of thioredoxin. Using a human thioredoxin in which the structural cysteines were mutated to alanine, Trx-C3A, we show that structural cysteines that do not take part in the catalytic functions of the protein are also important for its reactive oxygen scavenging properties. In addition, using a quadruple mutant Trx-C4A, where one of the catalytic cysteines, C35 was mutated to alanine in addition to the mutated structural cysteines, we demonstrated that catalytic cysteines are also required for the scavenging action of thioredoxin. Identification of thioredoxin as a (1)O(2) quencher and (*)OH scavenger may be of significant importance in explaining various redox-related antioxidant functions of thioredoxin.

Poisoning in children: Indian scenario

The retrospective data on childhood poisoning from eight regional hospitals in India has been reviewed. The demographic features and types of poisonings encountered have been compared. The analysis of the data indicated that pediatric poisonings constituted 0.23-3.3% of the total poisoning. The mortality ranged from 0.64-11.6% with highest being from Shimla. Accidental poisoning was common involving 50-90% of children below 5 years of age and males outnumbered the females. Suicidal poisoning was seen after 13 years of age and was due to drugs and household chemicals. One of the hospitals in Delhi recorded a very high incidence (66.6%) of drug poisoning in children. The drugs consumed belonged to phenothiazines, antiepileptics and antipyretics. Iron poisoning was seen in younger children. Kerosene was one of the causes of accidental poisoning at all hospitals except Shimla and rural Maharashtra were probably wood charcoal is widely used. Pesticide poisoning was more prevalent in Punjab and West Bengal whereas plant poisoning was very common in Shimla. Significant number of snake envenomation has been recorded from rural Maharashtra. Other less common accidental poisonings in children included alcohol, corrosives, heavy metals, rodenticides, detergents and disinfectants. Thus various regions in the country showed some variation in types and frequency of childhood poisoning which could be attributed to different geographical and socio-economic background.

Hemoglobin E disease in pregnancy

Abnormal hemoglobin patterns such as hemoglobin-E are rarely found in Western populations. The condition is fairly common in Southeast Asian countries such as Thailand, however. It is not commonly found in West Asian countries such as Saudi Arabia. A case report of hemoglobin E disease in pregnancy is made; its impact on pregnancy and labor is discussed.

Cardiac failure in pregnant Northern Nigerian women

Thirty-nine gravidae with congestive cardiac failure and ten pregnant patients with acute pulmonary edema treated at the Ahmadu Bello University Teaching Hospital in Kaduna, Nigeria, over a five-year period are presented. Congestive cardiac failure occurred more frequently in the postnatal period, and parity and socioeconomic class were not significantly related to cardiac failure. Maternal mortality was low in spite of all patients being in functional grades III and IV. Idiopathic cardiomegaly and chronic rheumatic heart disease were the most common underlying causes of heart failure in pregnancy. The dominant valvular lesions in the patients with rheumatic heart disease was mitral incompetence.