Anomalous partitioning of water in coexisting liquid phases of lipid multilayers near 100% relative humidity

Ternary lipid mixtures incorporating cholesterol are well-known to phase separate into liquid-ordered (L(o)) and liquid-disordered (L(d)) phases. In multilayers of these systems, the laterally phase separated domains register in columnar structures with different bilayer periodicities, resulting in hydrophobic mismatch energies at the domain boundaries. In this paper, we demonstrate via synchrotron-based X-ray diffraction measurements that the system relieves the hydrophobic mismatch at the domain boundaries by absorbing larger amounts of inter-bilayer water into the L(d) phase with lower d-spacing as the relative humidity approaches 100%. The lamellar repeat distance of the L(d) phase swells by an extra 4 Å, well beyond the equilibrium spacing predicted by the inter-bilayer forces. This anomalous swelling is caused by the hydrophobic mismatch energy at the domain boundaries, which produces a surprisingly long-range effect. We also demonstrate that the d-spacings of the lipid multilayers at 100% relative humidity do not change when bulk water begins to condense on the sample.

Thrombocytosis and Raised CRP Levels Predicts Advanced Stage in Esophageal Carcinoma

PURPOSE

The significance of thrombocytosis and raised C-reactive protein (CRP) as prognostic markers in esophageal cancer is unclear.

METHODS

We prospectively studied 50 consecutive patients with esophageal cancer and analyzed the relation of preoperative platelet count and CRP levels with the clinico-pathological characteristics and stage of the disease. The platelet count of 319 × 10(9)/L for thrombocytosis and CRP level >6 mg/dl were taken as cut-off values.

RESULTS

The incidence of thrombocytosis as well as raised CRP level was 50 %. Eighty percent of patients with thrombocytosis had raised CRP levels. None of patients with early disease (stage I) had thrombocytosis while patients with advanced stage were associated with thrombocytosis, 81.81 % in stage III and 100 % in stage IV (p < 0.001). The incidence of elevated CRP levels has shown progressive linear co-relation with the stage of carcinoma, i.e., 0 % in pathological stage I, 16.67 % in stage II, 45.45 % in stage III, and 100 % in stage IV disease (p = 0.011). Patients with thrombocytosis and patients with raised CRP were associated with pathological nodal metastases in 84.61 % cases (p 0.005) and 61.53 % (p 0.030), respectively.

CONCLUSION

Thrombocytosis alone or in combination with raised CRP had progressive linear relation with the stage of esophageal carcinoma.

Single-center trials in neonatology: Issues to consider

Single-center randomized controlled trials confer certain advantages over multi-center trials, in that they are cheaper and easier to design and conduct. However, recent research suggests that single-center trials are likely to overestimate treatment effects. There are notable examples in neonatology where results from multi-center trials have contradicted results of single-center studies. In this paper we discuss issues around external generalizability of single-center studies, and methodological issues that may cause bias.

Factors predicting mortality in newborn ventilation

OBJECTIVE

Prediction of mortality among newborns on mechanical ventilation is difficult. Our aim was to develop a scoring system for predicting mortality among such neonates.

METHODS

This multi centre prospective study was performed to develop and validate a scoring system among two equal cohorts of ventilated newborns in India. Mechanical ventilator was used in pressure-limited time-cycled mode. Arterial blood gas, initial pulmonary pressures, septicemia screen along with other basic parameters were recorded in a pre-structured proforma. Blood samples were analyzed for malondialdehyde to determine the possible role and predictive validity of free radical injury. Multiple logistic regression analysis was done to find out independent predictors of mortality for the variables those were significantly associated with outcome after univariate analysis.

RESULTS

On univariate analysis, birth-weight, oxygenation-index, septicaemia, malondialdehyde level, and inotropic support were significantly associated with mortality. However, after multiple regression analysis gestational-age, pH and FiO₂ lost their significance as predictors. According to cut-off values of ROC-curve, a scoring system ranging from 0 to 20 and four mortality risk groups were developed. Area under ROC-curve was 0.94, compared to 0.90 for both APACHE-III and CRIB-scores; and 0.92 for PRISM-score.

CONCLUSIONS

Birth-weight, oxygenation-index, malondialdehyde level, inotropic support, and septicemia are independent mortality predictors of neonatal ventilation. Increase in malondialdehyde level is associated with higher mortality rate, indicating possible role of free radical injury. Pediatr Pulmonol. 2015; 50:271-275. © 2014 Wiley Periodicals, Inc.

Accurate calibration and control of relative humidity close to 100% by X-raying a DOPC multilayer

In this study, we have designed a compact sample chamber that can achieve accurate and continuous control of the relative humidity (RH) in the vicinity of 100%. A 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) multilayer can be used as a humidity sensor by measuring its inter-layer repeat distance (d-spacing) via X-ray diffraction. We convert from DOPC d-spacing to RH according to a theory given in the literature and previously measured data of DOPC multilamellar vesicles in polyvinylpyrrolidone (PVP) solutions. This curve can be used for calibration of RH close to 100%, a regime where conventional sensors do not have sufficient accuracy. We demonstrate that this control method can provide RH accuracies of 0.1 to 0.01%, which is a factor of 10-100 improvement compared to existing methods of humidity control. Our method provides fine tuning capability of RH continuously for a single sample, whereas the PVP solution method requires new samples to be made for each PVP concentration. The use of this cell also potentially removes the need for an X-ray or neutron beam to pass through bulk water if one wishes to work close to biologically relevant conditions of nearly 100% RH.

X-ray photon correlation spectroscopy studies of surfaces and thin films

The technique of X-ray Photon Correlation Spectroscopy (XPCS) is reviewed as a method for studying the relatively slow dynamics of materials on time scales ranging from microseconds to thousands of seconds and length scales ranging from microns down to nanometers. We focus on the application of this technique to study dynamical fluctuations of surfaces, interfaces and thin films. We first discuss instrumental issues such as the effects of partial coherence (or alternatively finite instrumental resolution) and optimization of signal-to-noise ratios in the experiments. We then review what has been learned from recent XPCS studies of capillary wave fluctuations on liquid surfaces and polymer films, of nanoparticles used as probes to study the interior dynamics of polymer films, of liquid crystals and multilamellar surfactant films, and of metal surfaces, and magnetic domain wall fluctuations in antiferromagnets. We then discuss studies of non-equilibrium dynamics described by 2-time correlation functions. Finally, we briefly speculate on possible future XPCS experiments at new synchrotron sources currently under development including studies of dynamics on time scales down to femtoseconds.

Demonstration of feasibility of X-ray free electron laser studies of dynamics of nanoparticles in entangled polymer melts

The recent advent of hard x-ray free electron lasers (XFELs) opens new areas of science due to their exceptional brightness, coherence, and time structure. In principle, such sources enable studies of dynamics of condensed matter systems over times ranging from femtoseconds to seconds. However, the studies of "slow" dynamics in polymeric materials still remain in question due to the characteristics of the XFEL beam and concerns about sample damage. Here we demonstrate the feasibility of measuring the relaxation dynamics of gold nanoparticles suspended in polymer melts using X-ray photon correlation spectroscopy (XPCS), while also monitoring eventual X-ray induced damage. In spite of inherently large pulse-to-pulse intensity and position variations of the XFEL beam, measurements can be realized at slow time scales. The X-ray induced damage and heating are less than initially expected for soft matter materials.

Hereditary Multiple Gastrointestinal Atresia associated with Choledochal Cyst: A Rare Entity with Management Dilemma

Multiple intestinal atresias are rare and its treatment is challenging. Here, we present a case of multiple gastrointestinal atresia associated with choledochal cyst posing us a surgical challenge.

N-acetyltransferase 2, cytochrome P4502E1 and glutathione S-transferase genotypes in antitubercular treatment-induced hepatotoxicity in North Indians

WHAT IS KNOWN AND OBJECTIVE

Tuberculosis (TB) is a major cause of illness and death in developing countries. Hepatotoxicity is a serious side effect of antituberculosis treatment (ATT). NAT2, CYP2E1 and glutathione S-transferase (GST) gene polymorphisms may play an important role in ATT-induced hepatotoxicity. So, elucidating the genetics involved in anti-TB drug-induced hepatotoxicity in patients would be of utmost clinical significance. Therefore, the objective of the study was to elucidate the role of NAT2, CYP2E1 and GST gene polymorphisms in ATT-induced hepatotoxicity in North Indian patients.

METHODS

Three hundred patients with pulmonary and extra-pulmonary TB were enrolled. Total genomic DNA was isolated from each patient's peripheral lymphocytes using phenol-chloroform method, and genetic polymorphic analysis for N-acetyltransferase 2 (NAT2), cytochrome P4502E1 (CYP2E1) and GST was performed by polymerase chain reaction (PCR) with restriction fragment length polymorphism (RFLP).

RESULTS AND DISCUSSION

Of the 300 patients, 185 were males and 115 females. Among them, 33 males and 22 females developed ATT-induced hepatotoxicity. There were significant increases in alanine aminotransferase, aspartate aminotransferase and bilirubin levels in patients with ATT-induced hepatotoxicity at 1 month of treatment. NAT2 5/7 and 6/7 were significantly higher in hepatotoxicity patients as compared to the non-hepatotoxicity group. c1/c1 allele of CYP2E1 gene was lower (50·9%) in ATT-induced hepatotoxicity patients as compared to non-hepatotoxicity patients (61·2%), whereas c1/c2 and c2/c2 alleles were higher, but not statistically significant. GSTM1 was significantly higher in hepatotoxicity patients as compared to non-hepatotoxicity patients, whereas GSTT1 and GSTT1/M1 were lower, but not statistically significant.

WHAT IS NEW AND CONCLUSION

This study indicates that patients with slow-acetylator genotypes (NAT2 5/7, 6/7) and GSTM1 allele of GST enzyme were at higher risk of ATT-induced hepatotoxicity.

Dextran Carrier Macromolecules for Colon-specific Delivery of 5-Aminosalicylic Acid

Present manuscript describes the sustained and targeted delivery of 5-aminosalicylic acid to the distal ileum and proximal colon, using dextran (40 kDa) as a carrier for targeting 5-aminosalicylic acid at the colonic site by attaching p-aminobenzoic acid and benzoic acid as linkers. Prepared conjugate were characterized by UV, HPLC, FT-IR, and ¹H NMR. The degree of substitution was estimated by complete hydrolysis of conjugates in borate buffer and in vitro hydrolysis study of conjugates was performed in different biological media. It was observed that 5-aminosalicylic acid alone have produced high incidence of gastric ulcer with high ulcer index whereas lower ulcer index was found for the dextran conjugates of 5-aminosalicylic acid. The release pattern of conjugates in 3% w/v rat caecal content was confirmed the colon specificity of 5-aminosalicylic acid conjugates.

Pro-inflammatory and anti-inflammatory cytokine response in diarrhoea-predominant irritable bowel syndrome patients

BACKGROUND AND AIM

Irritable bowel syndrome (IBS) is referred to as a functional bowel disorder which is diagnosed by a number of characteristic symptoms (Rome II criteria) in the absence of detectable structural abnormalities. Low-grade inflammation of the intestine may be one of the reasons for development of diarrhoea-predominant IBS (IBS-D). We undertook this study to estimate the serum levels of pro-inflammatory (IL-6, TNF-alpha) and anti-inflammatory (IL-10) cytokines in IBS-D patients.

METHODS

A total of 108 diarrhoea patients were screened. Out of these only 63 adult IBS-D patients were enrolled. Age and sex matched 62 apparently healthy controls with no GI symptoms were also recruited. Out of 63 IBS-D patients, 37 were males while there were 32 males among the controls. The patients with IBS-D were diagnosed according to the Rome II criteria. Levels of serum IL-6, TNF-alpha and IL-10 were measured in all subjects using ELISA.

RESULTS

Mean (+/- SD) age of IBS-D patients (42.6 +/- 19.5 years) was comparable (p = 0.64) to that of controls (43.5 +/- 18.7 years). The mean (+/- SD) levels of IL-6 in IBS-D patients (32.2 +/- 12.01 pg/ml) was significantly higher (p < 0.001) than in controls (7.48 +/- 2.55 pg/ml). The levels of TNF-alpha in IBS-D patients (16.3 +/- 5.2 pg/ml) were also significantly higher (p < 0.05) than in controls (7.94 +/- 2.19 pg/ml). There was no significant difference in the serum levels of IL-10 (p = 0.23) between IBS-D patients (5.75 +/- 2.1 pg/ml) and controls (5.84 +/- 1.9 pg/ml).

CONCLUSION

Our results indicate that mild inflammation is involved in IBS-D patients as proinflammatory cytokines were increased although no difference in anti-inflammatory cytokine was observed.

Small intestinal bacterial overgrowth and orocecal transit time in patients of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) consists of Ulcerative colitis (UC) and Crohn's disease (CD). These two conditions share many common features-diarrhea, bloody stools, weight loss, abdominal pain, fever and fatigue. Small intestinal bacterial overgrowth (SIBO) is frequent in patients with CD but it has not been studied in UC Indian patients.

AIM

The study was planned to measure orocecal transit time (OCTT) and SIBO in UC and CD patients.

METHODS

One hundred thirty-seven patients of IBD (95 UC and 42 CD) and 115 healthy controls were enrolled. OCTT and SIBO were measured by lactulose and glucose hydrogen breath test respectively. Concentration of hydrogen and methane were measured by SC microlyser from Quintron, USA.

RESULTS

Mean±standard deviation (SD) of OCTT in patients of IBD was significantly higher as compared to controls. Furthermore, OCTT was significantly higher in CD patients as compared to UC patients. It was also observed that occurrence of SIBO was significantly higher in IBD patients as compared to controls. The occurrence of SIBO in CD (45.2%) was significantly higher as compared to patients in UC (17.8%) group. Percentage of methane positive IBD patients (2.9%) was significantly lower as compared to methane positive controls (24.4%).

CONCLUSION

OCTT was significantly delayed in IBD patients as compared to controls and in CD patients as compared to UC patients. OCTT was significantly higher in SIBO positive IBD patients as compared to SIBO negative patients. Thus, we can suggest that delayed OCTT would have been the cause of increased SIBO in these patients.

Jamming behavior of domains in a spiral antiferromagnetic system

Using resonant magnetic x-ray photon correlation spectroscopy, we show that the domains of a spiral antiferromagnet enter a jammed state at the onset of long-range order. We find that the slow thermal fluctuations of the domain walls exhibit a compressed exponential relaxation with an exponent of 1.5 found in a wide variety of solidlike jammed systems and can be qualitatively explained in terms of stress release in a stressed network. As the temperature decreases, the energy barrier for fluctuations becomes large enough to arrest further domain wall fluctuations, and the domains freeze into a spatial configuration within 10 K of the Néel temperature. The relaxation times can be fitted with the Vogel-Fulcher law as observed in polymers, glasses, and colloids, thereby indicating that the dynamics of domain walls in an ordered antiferromagnet exhibit some of the universal features associated with jamming behavior.

Long-range interlayer alignment of intralayer domains in stacked lipid bilayers

Liquid-crystalline phases of stacked lipid bilayers represent a pervasive motif in biomolecular assemblies. Here we report that, in addition to the usual smectic order, multicomponent multilayer membranes can exhibit columnar order arising from the coupling of two-dimensional intralayer phase separation and interlayer smectic ordering. This coupling propagates across hundreds of membrane lamellae, producing long-range alignment of phase-separated domains. Quantitative analysis of real-time dynamical experiments reveals that there is an interplay between intralayer domain growth and interlayer coupling, suggesting the existence of cooperative multilayer epitaxy. We postulate that such long-range epitaxy is solvent-assisted, and that it originates from the surface tension associated with differences in the network of hydrogen-bonded water molecules at the hydrated interfaces between the domains and the surrounding phase. Our findings might inspire the development of self-assembly-based strategies for the long-range alignment of functional lipid domains.

Comparison of lactulose and glucose breath test for diagnosis of small intestinal bacterial overgrowth in patients with irritable bowel syndrome

BACKGROUND AND AIMS

Validity of the lactulose breath test (LBT) to diagnose small intestinal bacterial overgrowth (SIBO) has been questioned. Therefore, a study was planned to compare LBT with glucose breath test (GBT) to diagnose SIBO in irritable bowel syndrome (IBS) patients and controls.

METHODS

175 diarrhea-predominant IBS patients and 150 apparently healthy controls were enrolled. IBS was diagnosed according to Rome II criteria. Breath samples were collected every 10 min up to 180 min. Breath H₂ and CH₄ were measured using an SC MicroLyzer. SIBO was positive with a sustained increase in breath H₂ or CH₄ or both ≥10 ppm over a baseline value within <90 min in case of LBT and within <120 min in GBT.

RESULTS

SIBO was positive in 60/175 (34.3%) patients by lactulose and in 11/175 (6.2%) patients by GBT. In controls, LBT was positive for SIBO in 45/150 (30%) patients and in 1/150 (0.66%) patients by GBT. Positive LBT for SIBO was not significantly different in patients and controls; while using GBT, SIBO was significantly higher (p < 0.01) in patients as compared to controls. By using GBT as gold standard for SIBO, sensitivity, specificity, positive predictive value and negative predictive value of LBT in IBS patients was 63.6, 67.7, 11.7 and 96.6% respectively.

CONCLUSION

LBT is not a good test to discriminate SIBO in IBS patients from controls.

Integration of tobacco cessation in general medical practice: need of the hour

Tobacco use is the single most preventable cause of death and disability. Tobacco use causes almost one million deaths annually in India, which is much more than the combined mortality due to malaria/TB and HIV/AIDS. It is estimated to cause one billion deaths in the 21st century, eighty per cent of which will occur in the developing countries like India. Tobacco use is increasing in the country. Global Adult Tobacco Survey, 2010, estimated that more than one-third of adults (35%) in the country use tobacco, out of which 21% use smokeless tobacco, 9% smoke and 5% use both. The prevalence of overall tobacco use among men was 47.9% and among women was 20.2%. Global Youth Tobacco Survey, India, 2009, estimate 14.6% of 13-15 years school going children use tobacco. There is urgent need for addressing the tobacco epidemic in India. Though effective interventions for tobacco cessation such as brief counselling, nicotine replacement therapy, non-nicotine pharmacotherapy are available, their use by general practitioners is restricted due to lack of adequate dissemination of information in their use. Use of these simple assessment tools and practice of these effective interventions by general medical and healthcare practitioners will go a long way in addressing the rising tobacco epidemic in India and making general healthcare more comprehensive.

Impact of an irreversibly adsorbed layer on local viscosity of nanoconfined polymer melts

We report the origin of the effect of nanoscale confinement on the local viscosity of entangled polystyrene (PS) films at temperatures far above the glass transition temperature. By using marker x-ray photon correlation spectroscopy with gold nanoparticles embedded in the PS films prepared on solid substrates, we have determined the local viscosity as a function of the distance from the polymer-substrate interface. The results show the impact of a very thin adsorbed layer (~7 nm in thickness) even without specific interactions of the polymer with the substrate, overcoming the effect of a surface mobile layer at the air-polymer interface and thereby resulting in a significant increase in the local viscosity as approaching the substrate interface.

Myth: mechanical ventilation is a therapeutic relic

Non-invasive respiratory support techniques such as continuous positive airway pressure (CPAP) have been increasingly used for management of surfactant-deficient lung disease in preterm infants. The successful use of this approach depends upon the condition of the baby at birth and requires the establishment of spontaneous breathing at birth. The reported advantages of CPAP in observational studies demonstrating a reduction in chronic lung disease have not been substantiated in recently reported well-designed randomised trials. This approach is now more established in larger and more mature preterm infants, and proper patient selection with close observation should be exercised when used in extremely low gestational age infants.