Divergent Roles of Escherichia Coli Encoded Lon Protease in Imparting Resistance to Uncouplers of Oxidative Phosphorylation: Roles of marA, rob, soxS and acrB

Uncouplers of oxidative phosphorylation dissipate the proton gradient, causing lower ATP production. Bacteria encounter several non-classical uncouplers in the environment, leading to stress-induced adaptations. Here, we addressed the molecular mechanisms responsible for the effects of uncouplers in Escherichia coli. The expression and functions of genes involved in phenotypic antibiotic resistance were studied using three compounds: two strong uncouplers, i.e., Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and 2,4-Dinitrophenol (DNP), and one moderate uncoupler, i.e., Sodium salicylate (NaSal). Quantitative expression studies demonstrated induction of transcripts encoding marA, soxS and acrB with NaSal and DNP, but not CCCP. Since MarA and SoxS are degraded by the Lon protease, we investigated the roles of Lon using a lon-deficient strain (Δlon). Compared to the wild-type strain, Δlon shows compromised growth upon exposure to NaSal or 2, 4-DNP. This sensitivity is dependent on marA but not rob and soxS. On the other hand, the Δlon strain shows enhanced growth in the presence of CCCP, which is dependent on acrB. Interestingly, NaSal and 2,4-DNP, but not CCCP, induce resistance to antibiotics, such as ciprofloxacin and tetracycline. This study addresses the effects of uncouplers and the roles of genes involved during bacterial growth and phenotypic antibiotic resistance. Strong uncouplers are often used to treat wastewater, and these results shed light on the possible mechanisms by which bacteria respond to uncouplers. Also, the rampant usage of some uncouplers to treat wastewater may lead to the development of antibiotic resistance.

Antimicrobial Resistance Studies Using Raman Spectroscopy on Clinically Relevant Bacterial Strains

There has been a steep rise in the emergence of antibiotic-resistant bacteria in the past few years. A timely diagnosis can help in initiating appropriate antibiotic therapy. However, conventional techniques for diagnosing antibiotic resistance are time-consuming and labor-intensive. Therefore, we investigated the potential of Raman spectroscopy as a rapid surveillance technology for tracking the emergence of antibiotic resistance. In this study, we used Raman spectroscopy to differentiate clinical isolates of antibiotic-resistant and -sensitive bacteria of Escherichia coli, Acinetobacter baumannii, and Enterobacter species. The spectra were collected with or without exposure to various antibiotics (ciprofloxacin, gentamicin, meropenem, and nitrofurantoin), each having a distinct mechanism of action. Ciprofloxacin- and meropenem-treated sensitive strains showed a decrease in the intensity of Raman bands associated with DNA (667, 724, 785, 1378, 1480, and 1575 cm^-1) and proteins (640 and 1662 cm^-1), coupled with an increase in the intensity of lipid bands (891, 960, and 1445 cm^-1). Gentamicin- and nitrofurantoin-treated sensitive strains showed an increase in the intensity of nucleic acid bands (668, 724, 780, 810, 1378, 1480, and 1575 cm^-1) while a decrease in the intensity of protein bands (640, 1003, 1606, and 1662 cm^-1) and the lipid band (1445 cm^-1). The Raman spectral changes observed in the antibiotic-resistant strains were opposite to that of antibiotic-sensitive strains. The Raman spectral data correlated well with the antimicrobial susceptibility test results. The Raman spectral dataset was used for partial least-squares (PLS) analysis to validate the biomarkers obtained from the univariate analysis. Overall, this study showcases the potential of Raman spectroscopy for detecting antibiotic-resistant and -sensitive bacteria.

Herbicides 2,4-Dichlorophenoxy Acetic Acid and Glyphosate Induce Distinct Biochemical Changes in E. coli during Phenotypic Antibiotic Resistance: A Raman Spectroscopic Study

Antibiotic resistance is a major global health concern. The increased use of herbicides may lead to multiple antibiotic resistance in bacteria. Conventional techniques for diagnosing antibiotic resistance are laborious, time-intensive, expensive, and lack information about antibiotic susceptibility. On the other hand, Raman spectroscopy is a rapid, label-free, noninvasive alternative to traditional techniques to detect antibiotic resistance. In this study, two popular herbicides 2,4-dichlorophenoxy acetic acid (2,4-D) and N-(phosphonomethyl)glycine (glyphosate) were used to study their effects on the emergence of antibiotic resistance. The Escherichia coli wild-type (WT) MG1655 strain and two isogenic mutants, Δlon and ΔacrB, were used together with Raman spectroscopy. The WT E. coli is sensitive to antibiotics, but exposure to both herbicides induces antibiotic resistance. Using an excitation wavelength of 785 nm, the intensity ratios (e.g., I₇₄₀/I₇₈₅, I₇₄₀/I₁₀₀₃, I₁₄₈₀/I₁₄₄₅, I₂₉₃₄/I₂₈₆₈, and I₂₉₃₄/I₂₈₄₅) were identified as biomarkers to study the induction of antibiotic resistance in bacteria but not NaCl-mediated stress. Using an excitation wavelength of 633 nm, the peak intensity at 740 cm^-1 assigned to cytochrome bd decreases under antibiotic stress but increases upon exposure to both herbicides and antibiotics, indicating the development of resistance. Thus, this study can be applied to monitor antibiotic resistance using Raman spectroscopy.

Machine Learning in Differentiating Gliomas from Primary CNS Lymphomas: A Systematic Review, Reporting Quality, and Risk of Bias Assessment

BACKGROUND

Differentiating gliomas and primary CNS lymphoma represents a diagnostic challenge with important therapeutic ramifications. Biopsy is the preferred method of diagnosis, while MR imaging in conjunction with machine learning has shown promising results in differentiating these tumors.

PURPOSE

Our aim was to evaluate the quality of reporting and risk of bias, assess data bases with which the machine learning classification algorithms were developed, the algorithms themselves, and their performance.

DATA SOURCES

Ovid EMBASE, Ovid MEDLINE, Cochrane Central Register of Controlled Trials, and the Web of Science Core Collection were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

STUDY SELECTION

From 11,727 studies, 23 peer-reviewed studies used machine learning to differentiate primary CNS lymphoma from gliomas in 2276 patients.

DATA ANALYSIS

Characteristics of data sets and machine learning algorithms were extracted. A meta-analysis on a subset of studies was performed. Reporting quality and risk of bias were assessed using the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) and Prediction Model Study Risk Of Bias Assessment Tool.

DATA SYNTHESIS

The highest area under the receiver operating characteristic curve (0.961) and accuracy (91.2%) in external validation were achieved by logistic regression and support vector machines models using conventional radiomic features. Meta-analysis of machine learning classifiers using these features yielded a mean area under the receiver operating characteristic curve of 0.944 (95% CI, 0.898-0.99). The median TRIPOD score was 51.7%. The risk of bias was high for 16 studies.

LIMITATIONS

Exclusion of abstracts decreased the sensitivity in evaluating all published studies. Meta-analysis had high heterogeneity.

CONCLUSIONS

Machine learning-based methods of differentiating primary CNS lymphoma from gliomas have shown great potential, but most studies lack large, balanced data sets and external validation. Assessment of the studies identified multiple deficiencies in reporting quality and risk of bias. These factors reduce the generalizability and reproducibility of the findings.

Cell-free hemoglobin is a marker of systemic inflammation in mouse models of sepsis: a Raman spectroscopic study

Sepsis is a life-threatening condition caused by heightened host immune responses post infection. Despite intensive research, most of the existing diagnostic methods remain non-specific, labour-intensive, time-consuming or are not sensitive enough for rapid and timely diagnosis of the onset and progression of sepsis. The present work was undertaken to explore the potential of Raman spectroscopy to identify the biomarkers of sepsis in a label-free and minimally invasive manner using different mouse models of inflammation. The sera of BALB/c mice infected with Salmonella Typhimurium reveal extensive hemolysis, as indicated by the Raman bands that are characteristic of the porphyrin ring of hemoglobin (668, 743, 1050, 1253 and 1397 cm-1) which increase in a kinetic manner. These markers are also observed in a lipopolysaccharide-induced endotoxic shock model, but not in a thioglycollate-induced sterile peritonitis model. These data demonstrate that hemolysis is a signature of systemic, but not localised, inflammation. To further validate our observations, sepsis was induced in the nitric oxide synthase 2 (Nos2-/-) deficient strain which is more sensitive to infection. Interestingly, Nos2-/- mice exhibit a higher degree of hemolysis than C57BL/6 mice. Sepsis-induced hemolysis was also confirmed using resonance Raman spectroscopy with 442 nm excitation which demonstrated a pronounced increase in the resonant Raman bands at 670 and 1350 cm-1 in sera of the infected mice. This is the first study to identify inflammation-induced hemolysis in mouse models of sepsis using Raman spectral signatures for hemoglobin. The possible implications of this method in detecting hemolysis in different inflammatory pathologies, such as the ongoing COVID-19 pandemic, are discussed.

T cell costimulation, checkpoint inhibitors and anti-tumor therapy

The hallmarks of the adaptive immune response are specificity and memory. The cellular response is mediated by T cells which express cell surface T cell receptors (TCRs) that recognize peptide antigens in complex with major histocompatibility complex (MHC) molecules on antigen presenting cells (APCs). However, binding of cognate TCRs with MHC-peptide complexes alone (signal 1) does not trigger optimal T cell activation. In addition to signal 1, the binding of positive and negative costimulatory receptors to their ligands modulates T cell activation. This complex signaling network prevents aberrant activation of T cells. CD28 is the main positive costimulatory receptor on naı¨ve T cells; upon activation, CTLA4 is induced but reduces T cell activation. Further studies led to the identification of additional negative costimulatory receptors known as checkpoints, e.g. PD1. This review chronicles the basic studies in T cell costimulation that led to the discovery of checkpoint inhibitors, i.e. antibodies to negative costimulatory receptors (e.g. CTLA4 and PD1) which reduce tumor growth. This discovery has been recognized with the award of the 2018 Nobel prize in Physiology/Medicine. This review highlights the structural and functional roles of costimulatory receptors, the mechanisms by which checkpoint inhibitors work, the challenges encountered and future prospects.

Multicellular String-Like Structure Formation by Salmonella Typhimurium Depends on Cellulose Production: Roles of Diguanylate Cyclases, YedQ and YfiN

Bacteria face diverse stresses in the environment and, sometimes, respond by forming multi-cellular structures, e.g., biofilms. Here, we report a novel macroscopic and multi-cellular structure formed by Salmonella Typhimurium, which resembles small strings. These string-like structures, ∼1 cm long, are induced under some stress conditions: iron deprivation by 2,2-Bipyridyl or low amounts of antibiotics or ethanol in minimal media. However, cells in strings revert back to planktonic growth upon return to nutrient rich media. Compared to planktonic cells, strings are more resistant to antibiotics and oxidative stress. Also, strains lacking csgD or rpoS, which are defective in the classical rdar biofilm formation, form strings. Furthermore, some biofilm inducing conditions do not result in strings and vice-versa, demonstrating that strings are not related to classical CsgD-dependent biofilms. Cells in a string are held together by cellulose and a strain lacking bcsA, which is defective in cellulose production, does not form strings. In addition, reductive stress conditions such as dithiothreitol (DTT) or mutations in the Disulfide bonding system (DSB) also give rise to strings. The amounts of c-di-GMP are increased upon string formation and studies with single and double deletion strains of the diguanylate cyclases, yedQ (STM1987) primarily and yfiN (STM2672) partly, revealed their importance for string formation. This is the first study showcasing the ability of Salmonella to produce high amounts of cellulose in liquid culture, instead of an interface, in a CsgD-independent manner. The relevance and possible applications of strings in the production of bacterial cellulose and bioremediation are discussed.

Profiling antibiotic resistance in Escherichia coli strains displaying differential antibiotic susceptibilities using Raman spectroscopy

The rapid identification of antibiotic resistant bacteria is important for public health. In the environment, bacteria are exposed to sub-inhibitory antibiotic concentrations which has implications in the generation of multi-drug resistant strains. To better understand these issues, Raman spectroscopy was employed coupled with partial least squares-discriminant analysis to profile Escherichia coli strains treated with sub-inhibitory concentrations of antibiotics. Clear differences were observed between cells treated with bacteriostatic (tetracycline and rifampicin) and bactericidal (ampicillin, ciprofloxacin, and ceftriaxone) antibiotics for 6 hr: First, atomic force microscopy revealed that bactericidal antibiotics cause extensive cell elongation whereas short filaments are observed with bacteriostatic antibiotics. Second, Raman spectral analysis revealed that bactericidal antibiotics lower nucleic acid to protein (I₈₁₂ /I₈₃₀ ) and nucleic acid to lipid ratios (I₁₄₈₃ /I₁₄₅₂ ) whereas the opposite is seen with bacteriostatic antibiotics. Third, the protein to lipid ratio (I₂₉₃₆ /I₂₈₈₅ and I₂₉₃₆ /I₂₈₅₀ ) is a Raman stress signature common to both the classes. These signatures were validated using two mutants, Δlon and ΔacrB, that exhibit relatively high and low resistance towards antibiotics, respectively. In addition, these spectral markers correlated with the emergence of phenotypic antibiotic resistance. Overall, this study demonstrates the efficacy of Raman spectroscopy to identify resistance in bacteria to sub-lethal concentrations of antibiotics.

Identification of a resonance Raman marker for cytochrome to monitor stress responses in Escherichia coli

Raman spectroscopy and resonance Raman spectroscopy are widely used to study bacteria and their responses to different environmental conditions. In the present study, the identification of a novel resonance Raman peak for Escherichia coli, recorded with 633 nm laser excitation is discussed. A peak at 740 cm^-1 is observed exclusively with 633 nm excitation but not with 514 nm or 785 nm excitation. This peak is absent in the lag phase but appears in the log phase of bacterial growth. The intensity of the peak increases at high temperature (45 °C) compared with growth at low temperature (25 °C) or the physiological temperature (37 °C). Although osmotic stress lowered bacterial growth, the intensity of this peak was unaffected. However, treatment with chemical uncouplers of oxidative phosphorylation resulted in significantly lower intensity of this Raman band, indicating its possible involvement in respiration. Cytochromes, a component of bacterial respiration' can show resonance enhancement at 633 nm due to the presence of a shoulder in that region depending on the type and conformation of cytochrome. Therefore, the peak intensity was monitored in different genetic mutants of E. coli lacking cytochromes. This peak is absent in the Escherichia coli mutant lacking cydB, but not ccmE, demonstrating the contribution of cytochrome bd subunit II in the peak's origin. In future, this newly found cytochrome marker can be used for biochemical assessment of bacteria exposed to various conditions. Overall, this finding opens the scope for use of red laser excitation in resonance Raman in monitoring stress and respiration in bacteria. Graphical abstract.

Understanding the effects of culture conditions in bacterial growth: A biochemical perspective using Raman microscopy

Rapid, sensitive and label-free methods to probe bacterial growth irrespective of the culture conditions can shed light on the mechanisms by which bacteria adapt to different environmental stimuli. Raman spectroscopy can rapidly and continuously monitor the growth of bacteria under varied conditions. In this study, the growth of Escherichia coli in Luria broth (nutrient rich conditions) and minimal media with either glucose or glycerol as carbon source (nutrient limiting conditions) is profiled using Raman spectroscopy. Moreover, the study also gives insights into the altered bacterial biochemistry upon exposure to low- (25°C) and high-temperature (45°C) stress. Raman spectral measurement was performed on bulk bacteria cultured under laboratory conditions. A detailed analysis of the spectra as a function of bacterial growth reveals changes in Raman band intensities/area of biomolecules such as DNA, proteins and lipids. We also report five novel ratiometric markers (I₈₃₀ /I₈₁₀ , I₁₁₂₆ /I₁₁₀₀ , I₁₃₄₀ /I₁₄₄₀ , I₁₂₀₇ /I₁₂₄₀ and I₁₅₈₀ /I₁₄₄₀ ) that can identify the phase of growth, independent of the culture condition. Unsupervised multivariate methods like Principal Component Analysis also corroborate the aforementioned markers of growth. Altogether, our findings highlight the potential of Raman spectroscopy in yielding universal biochemical signatures that may be indicative of stress and aging in a growth milieu.

Raman spectroscopy reveals distinct differences between two closely related bacterial strains, Mycobacterium indicus pranii and Mycobacterium intracellulare

A common technique used to differentiate bacterial species and to determine evolutionary relationships is sequencing their 16S ribosomal RNA genes. However, this method fails when organisms exhibit high similarity in these sequences. Two such strains that have identical 16S rRNA sequences are Mycobacterium indicus pranii (MIP) and Mycobacterium intracellulare. MIP is of significance as it is used as an adjuvant for protection against tuberculosis and leprosy; in addition, it shows potent anti-cancer activity. On the other hand, M. intracellulare is an opportunistic pathogen and causes severe respiratory infections in AIDS patients. It is important to differentiate these two bacterial species as they co-exist in immuno-compromised individuals. To unambiguously distinguish these two closely related bacterial strains, we employed Raman and resonance Raman spectroscopy in conjunction with multivariate statistical tools. Phenotypic profiling for these bacterial species was performed in a kinetic manner. Differences were observed in the mycolic acid profile and carotenoid pigments to show that MIP is biochemically distinct from M. intracellulare. Resonance Raman studies confirmed that carotenoids were produced by both MIP as well as M. intracellulare, though the latter produced higher amounts. Overall, this study demonstrates the potential of Raman spectroscopy in differentiating two closely related mycobacterial strains. Graphical abstract.

Non-steroidal anti-inflammatory drugs, acetaminophen and ibuprofen, induce phenotypic antibiotic resistance in Escherichia coli: roles of marA and acrB

The factors contributing to antibiotic resistance in bacteria are an important area of study. Sodium salicylate (NaSal), a non-steroidal anti-inflammatory drug (NSAID), increases antibiotic resistance by inducing the expression of MarA, a transcription factor, which increases the AcrAB-TolC efflux pump. MarA is a substrate of Lon protease and the Δlon strain displays a high degree of antibiotic resistance. This study was initiated to identify commonly used NSAIDs that may induce antibiotic resistance and to compare their efficacies with NaSal and acetyl salicylic acid (ASA). Quantitative real-time expression analysis revealed induction of marA and acrB by NaSal, ASA, acetaminophen (APAP) and ibuprofen. Further, dose studies demonstrated that NaSal and ASA induce resistance at ∼2 mM while APAP and ibuprofen induce resistance at ∼5-10 mM. To dissect the roles of key molecules, atomic force microscopy and functional studies were performed using WT, Δlon, ΔmarA, ΔacrB, ΔlonΔmarA and ΔlonΔacrB strains. The induction of antibiotic resistance by NaSal, ASA and APAP is relatively higher and is partly dependent on marA, whereas ibuprofen which induces lower antibiotic resistance shows complete marA dependence. Notably, NaSal, ASA, APAP and ibuprofen induce antibiotic resistance in an acrB-dependent manner. The possible significance of some NSAIDs in inducing antibiotic resistance is discussed.

Unusual presentation of chondroblastoma mimicking Trevor's disease

Chondroblastoma is a benign bone tumor, represents 1%–2% of all primary bone tumors, typically seen in patients 10–25-year-old and more common in males. It occurs most frequently in the distal femur, proximal tibia, and proximal humerus. Soft tissue extension is extremely rare. Adjacent joints may develop effusions, but the tumor mass protruding into the joint has never been seen in case of chondroblastoma. We report a rare case of intra-articular chondroblastoma arising from proximal tibia in a 16-year-old boy and growing into the knee joint mimicking an intra-articular osteochondroma.

Feasibility of measuring psychological resilience in hospitalized patients with acute illness: The Resilience After the Trauma of Acute Illness (RAFT) study

Resilience is the 'ability to bounce back'. We want to investigate whether measurement of resilience during an acute hospital admission is feasible. We conducted a feasibility study. Resilience was measured using the Brief Resilience Scale. Results were contextualized by measuring chronic disease burden, anxiety, depression, coping strategies and personality traits. 56 or 103 patients approached took part in the study. A group of 12 patients undergoing pulmonary rehabilitation served as a control group. We found evidence of low resilience in 4/44 (9%) patients admitted as medical emergencies. Low resilience was statistically related to the Hospital Anxiety and Depression Scale and a number of coping strategies and personality traits. We found no relation between measures of resilience and previous admissions to hospital. The concept of resilience might be applicable to unscheduled admissions to hospital. Larger studies are required to establish whether low resilience is common and amenable to intervention. REC number 17/WA/0024.

Evaluation of AAA and XVMC Algorithms for Dose Calculation in Lung Equivalent Heterogeneity in Photon Fields: A Comparison of Calculated Results with Measurements

AIMS

The aims of the present work are (1) to evaluate dose calculation accuracy of two commonly used algorithms for 15 MV small photon fields in a medium encompassing heterogeneity and (2) to compare them with measured results obtained from gafchromic film EBT2.

MATERIALS AND METHODS

Authors employed kailwood (Pinus Wallichiana) to mimic lung. Briefly, seven Kailwood plates, each measuring 25x25 cm² of varying thicknesses totaling 13 cm equivalent to the mean thickness of an adult human lung, were sandwiched between 5 cm tissue equivalent material from top and 10 cm below. Physical measurements were performed using Radiochromic film EBT2. The field sizes of 1x1, 2x2, 5x5 and 10x10 cm² were selected at 100 cm SSD. Simulations were performed using EGSnrc/DOSRZnrc Monte Carlo code. The dose variation inside the inhomogeneity and near the interface was calculated using AAA & XVMC algorithm.

RESULTS

Preliminary results show that there is large variation of dose inside inhomogeneity. The maximum variation of dose inside the inhomogeneity for 1x1 cm² was found 40% by AAA and 4.5% by XVMC compared to measured/simulated results. For the field size of 2x2 cm², these figures were 27% by AAA & 3.5% by XVMC. For 5x5 cm² field size, the variation is small which becomes insignificant for larger fields.

CONCLUSION

The results presented in this work indicate that for smaller fields, XVMC algorithm gives more realistic prediction, while there is the need for caution on using AAA algorithm for dose calculations involving small area irradiation encompassing heterogeneities and low-density media.

Redox-dependent condensation of the mycobacterial nucleoid by WhiB4

Oxidative stress response in bacteria is mediated through coordination between the regulators of oxidant-remediation systems (e.g. OxyR, SoxR) and nucleoid condensation (e.g. Dps, Fis). However, these genetic factors are either absent or rendered non-functional in the human pathogen Mycobacterium tuberculosis (Mtb). Therefore, how Mtb organizes genome architecture and regulates gene expression to counterbalance oxidative imbalance is unknown. Here, we report that an intracellular redox-sensor, WhiB4, dynamically links genome condensation and oxidative stress response in Mtb. Disruption of WhiB4 affects the expression of genes involved in maintaining redox homeostasis, central metabolism, and respiration under oxidative stress. Notably, disulfide-linked oligomerization of WhiB4 in response to oxidative stress activates the protein’s ability to condense DNA. Further, overexpression of WhiB4 led to hypercondensation of nucleoids, redox imbalance and increased susceptibility to oxidative stress, whereas WhiB4 disruption reversed this effect. In accordance with the findings in vitro, ChIP-Seq data demonstrated non-specific binding of WhiB4 to GC-rich regions of the Mtb genome. Lastly, data indicate that WhiB4 deletion affected the expression of ~ 30% of genes preferentially bound by the protein, suggesting both direct and indirect effects on gene expression. We propose that WhiB4 structurally couples Mtb’s response to oxidative stress with genome organization and transcription.

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Genome condensation is involved in the management of oxidative stress in bacteria.

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A relation between the genome condensation and oxidative stress is unclear in Mtb.

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A redox sensor WhiB4 calibrates genome-condensation and antioxidants in Mtb.

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Over-expression of WhiB4 hyper-condensed genome and induced killing by oxidants.

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WhiB4 deficiency delayed genome condensation and promoted oxidative stress survival.

Challenges in application of Raman spectroscopy to biology and materials

Raman spectroscopy has become an essential tool for chemists, physicists, biologists and materials scientists. In this article, we present the challenges in unravelling the molecule-specific Raman spectral signatures of different biomolecules like proteins, nucleic acids, lipids and carbohydrates based on the review of our work and the current trends in these areas. We also show how Raman spectroscopy can be used to probe the secondary and tertiary structural changes occurring during thermal denaturation of protein and lysozyme as well as more complex biological systems like bacteria. Complex biological systems like tissues, cells, blood serum etc. are also made up of such biomolecules. Using mice liver and blood serum, it is shown that different tissues yield their unique signature Raman spectra, owing to a difference in the relative composition of the biomolecules. Additionally, recent progress in Raman spectroscopy for diagnosing a multitude of diseases ranging from cancer to infection is also presented. The second part of this article focuses on applications of Raman spectroscopy to materials. As a first example, Raman spectroscopy of a melt cast explosives formulation was carried out to monitor the changes in the peaks which indicates the potential of this technique for remote process monitoring. The second example presents various modern methods of Raman spectroscopy such as spatially offset Raman spectroscopy (SORS), reflection, transmission and universal multiple angle Raman spectroscopy (UMARS) to study layered materials. Studies on chemicals/layered materials hidden in non-metallic containers using the above variants are presented. Using suitable examples, it is shown how a specific excitation or collection geometry can yield different information about the location of materials. Additionally, it is shown that UMARS imaging can also be used as an effective tool to obtain layer specific information of materials located at depths beyond a few centimeters.

This paper reviews various facets of Raman spectroscopy. This encompasses biomolecule fingerprinting and conformational analysis, discrimination of healthy vs. diseased states, depth-specific information of materials and 3D Raman imaging.

Association of Relationship between Periodontal Disease and Cardiovascular Disease

The present study was undertaken to determine the relationship between periodontal and cardiovascular disease. Previous studies have shown some co-relation between the two conditions. We included 186 patients divided into four groups. First two Groups (A1 & A2) were the patients with cardiac disease (100 in numbers) whilst Groups (B1 & B2) (86 in numbers) were treated as controls (without cardiac disease). Following markers of periodontal disease were assessed - plaque index, calculus index, gingival and periodontal index. Markers of cardiovascular disease included were LDL, HDL, total cholesterol and CRP. Ramfjords periodontal index was used to assess the extent of periodontal disease. In the present study there was a significant increase in CRP levels in Group A1 (CVD + PD) compared to controls and overall the two cardiac groups showed a significant increase in CRP compared to controls. There was a non-significant change in lipid profile markers (LDL, HDL and total cholesterol). Periodontal Disease Index (PDI) was also increased in Group A1 compared to other groups except Group B1 and overall in cardiac groups compared to non-cardiac (PD) groups. In this study no correlation between periodontal and cardiovascular disease was found. This may be due intake of statins by few patients in Group A with a confirmed diagnosis of cardiovascular disease.

Performance Evaluation of Algorithms in Lung IMRT: A comparison of Monte Carlo, Pencil Beam, Superposition, Fast Superposition and Convolution Algorithms

BACKGROUND

Inclusion of inhomogeneity corrections in intensity modulated small fields always makes conformal irradiation of lung tumor very complicated in accurate dose delivery.

OBJECTIVE

In the present study, the performance of five algorithms via Monte Carlo, Pencil Beam, Convolution, Fast Superposition and Superposition were evaluated in lung cancer Intensity Modulated Radiotherapy planning.

MATERIALS AND METHODS

Treatment plans for ten lung cancer patients previously planned on Monte Carlo algorithm were re-planned using same treatment planning indices (gantry angel, rank, power etc.) in other four algorithms.

RESULTS

The values of radiotherapy planning parameters such as Mean dose, volume of 95% isodose line, Conformity Index, Homogeneity Index for target, Maximum dose, Mean dose; %Volume receiving 20Gy or more by contralateral lung; % volume receiving 30 Gy or more; % volume receiving 25 Gy or more, Mean dose received by heart; %volume receiving 35Gy or more; %volume receiving 50Gy or more, Mean dose to Easophagous; % Volume receiving 45Gy or more, Maximum dose received by Spinal cord and Total monitor unit, Volume of 50 % isodose lines were recorded for all ten patients. Performance of different algorithms was also evaluated statistically.

CONCLUSION

MC and PB algorithms found better as for tumor coverage, dose distribution homogeneity in Planning Target Volume and minimal dose to organ at risks are concerned. Superposition algorithms found to be better than convolution and fast superposition. In the case of tumors located centrally, it is recommended to use Monte Carlo algorithms for the optimal use of radiotherapy.

Emergence of core-peripheries in networks

A number of important transport networks, such as the airline and trade networks of the world, exhibit a characteristic core-periphery structure, wherein a few nodes are highly interconnected and the rest of the network frays into a tree. Mechanisms underlying the emergence of core-peripheries, however, remain elusive. Here, we demonstrate that a simple pruning process based on removal of underutilized links and redistribution of loads can lead to the emergence of core-peripheries. Links are assumed beneficial if they either carry a sufficiently large load or are essential for global connectivity. This incentivized redistribution process is controlled by a single parameter, which balances connectivity and profit. The obtained networks exhibit a highly resilient and connected core with a frayed periphery. The balanced network shows a higher resilience than the world airline network or the world trade network, revealing a pathway towards robust structural features through pruning.

Raman and infra-red microspectroscopy: towards quantitative evaluation for clinical research by ratiometric analysis

We demonstrate how ratioing spectral bands can circumvent experimental artefacts, and present a library of ratios from the biomedical literature.

Molecular profiling of sepsis in mice using Fourier Transform Infrared Microspectroscopy

Sepsis is a life threatening condition resulting from a high burden of infection. It is a major health care problem and associated with inflammation, organ dysfunction and significant mortality. However, proper understanding and delineating the changes that occur during this complex condition remains a challenge. A comparative study involving intra-peritoneal injection of BALB/c mice with Salmonella Typhimurium (infection), lipopolysaccharide (endotoxic shock) or thioglycollate (sterile peritonitis) was performed. The changes in organs and sera were profiled using immunological assays and Fourier Transform Infrared (FTIR) micro-spectroscopy. There is a rapid rise in inflammatory cytokines accompanied with lowering of temperature, respiratory rate and glucose amounts in mice injected with S. Typhimurium or lipopolysaccharide. FTIR identifies distinct changes in liver and sera: decrease in glycogen and protein/lipid ratio and increase in DNA and cholesteryl esters. These changes were distinct from the pattern observed in mice treated with thioglycollate and the differences in the data obtained between the three models are discussed. The combination of FTIR spectroscopy and other biomarkers will be valuable in monitoring molecular changes during sepsis.

Prevalence and risk factors associated with worm infestation in pre-school children (6-23 months) in selected blocks of Uttar Pradesh and Jharkhand, India

BACKGROUND

Intestinal worm infestation is widely prevalent in developing countries and can result in impaired nutrition and development.

AIMS

To estimate prevalence of and risk factors for intestinal geohelminths and other intestinal parasites in children aged 6 to 23 months.

SETTINGS AND DESIGN

Cross sectional study in rural India.

MATERIALS AND METHODS

Proportionate population size sampling method was used to randomly select 15 villages per block. Thereafter, house-to-house survey was done to recruit eligible children and obtain fecal sample for microbiological examination.

STATISTICAL ANALYSIS

Univariate distribution of variables was assessed and comparison between categorical variables and continuous variables was done using a Chi-square test and student's t-test, respectively. Odds ratio was calculated to assess associations.

RESULTS

Overall 926 children were recruited and 909 fecal samples examined. Combined prevalence of infestation with intestinal geohelminths treatable by albendazole and other intestinal parasites non-treatable by albendazole was 50.3% (457/909) and 51.6% (469/909), respectively. Exclusive use of hand pump water (OR = 1.79, CI = 1.36-2.35, P CONCLUSION: Since almost half the children are infected with intestinal geohelminths treatable by albendazole, targeted deworming of population in this age group should be considered.

Portrayal of health-related behaviours in popular UK television soap operas

BACKGROUND

Evidence suggests that health-related story lines in popular television programmes may lead to increased viewer knowledge or behaviour change. However, little is currently known about the portrayal of common health-related behaviours on UK television soap operas.

METHODS

The portrayal of 11 key health-related behaviours on the 4 most popular soap operas set and broadcast in the UK over 4 weeks in spring 2005 was assessed.

RESULTS

Seven of the 11 behaviours of interest were recorded a total of 959 times during 32 h of programming (or 30 behaviours per programming hour). The behaviour most frequently recorded was alcohol-related behaviours, recorded 619 times (19.3 per programming hour). No instances of four behaviours of interest were observed: driving soon after drinking, drinking during pregnancy, smoking during pregnancy or smoking around children.

CONCLUSIONS

Popular television serials offer the chance to portray "healthy" behaviours as normal, and so help change attitudes and shape behavioural norms among the viewing public. Engaging the makers of these programmes in a health promotion agenda may be a fruitful method of promoting healthy behaviours.

Chromium (VI) biosorption and bioaccumulation by chromate resistant bacteria

In this study, strains that are capable of bioaccumulating Cr(VI) were isolated from treated tannery effluent of a common effluent treatment plant. The Cr(VI) concentration in this treated effluent was 0.96 mg/l, much above the statutory limit of 0.1 mg/l for discharge of industrial effluents into inland surface waters in India. In addition to the bioaccumulation, biosorption capabilities of living and dead cells were analysed. Two strains, identified as Bacillus circulans and Bacillus megaterium were able to bioaccumulate 34.5 and 32.0 mg Cr/g dry weight, respectively and brought the residual concentration of Cr(VI) to the permissible limit in 24 h when the initial concentration was 50 mg Cr(VI)/l. Our experimental design accounts for initial as well as final residual concentration of heavy metal while selecting heavy metal accumulating strains during batch studies. Biosorption of Cr(VI) was shown by B. megaterium and an another strain, B. coagulans. Living and dead cells of B. coagulans biosorbed 23.8 and 39.9 mg Cr/g dry weight, respectively, whereas, 15.7 and 30.7 mg Cr/g dry weight was biosorbed by living and dead cells of B. megaterium, respectively. Biosorption by the dead cells was higher than the living cells. This was due to prior pH conditioning (pH 2.5 with deionized water acidified with H2SO4) of the dead cells.

Chromate tolerant bacteria isolated from tannery effluent

The occurrence of metal tolerant and antibiotic resistant organisms was investigated in tannery effluent. Seventy-seven isolates comprising heterotrophs (41) and coliforms (36) which were tolerant to chromate level of > 50 microg/ml were selected for detailed study. The majority of the coliforms were resistant to higher levels of chromate (200 microg/ml) whereas around 3% of the heterotrophs were resistant to Cr6+ at a level of > 150 microg/ml. All chromate tolerant heterotrophs were also tolerant to Cu2+ (100%) whereas only 58.53% coliforms were tolerant to Cu2+. Except in the case of Cd2+ a higher number of heterotrophs were found tolerant to other heavy metals tested. Both groups of isolates were found sensitive to mercury. Resistance to cephaloridine was more abundant (P < 0.001) in coliforms as compared to heterotrophs. On the other hand a significantly higher number (P < 0.01) of heterotrophs showed resistance to streptomycin and carbencillin. All coliforms were sensitive to chloramphenicol. Around 80%) and 31.70% of coliforms and heterotrophs exhibited a relationship to the combination of metals and antibiotics. Both heterotrophs and coliforms tolerant to Hg2+ were also resistant to polymixin-B.