A prospective observational study on changes in endo-tracheal tube cuff pressure and its correlation with airway pressures during various stages of robotic pelvic surgeries.

Background and Aims: Robotic surgeries often require a relatively long duration of pneumo-peritoneum and trendelenburg position which may accentuate changes in endo-tracheal tube (ETT) cuff pressure leading to pressure related complications. The aim of this study was to analyze changes in ETT cuff pressures during various stages of pneumo-peritoneum and surgical positioning and its correlation with airway pressure changes. Material and Methods: A prospective observational study was planned after approval of institutional review board on 60 patients undergoing elective robotic pelvic surgery requiring head down position. Baseline cuff pressure was adjusted to 25 cm H2O. ETT cuff pressure, peak airway pressure and end tidal CO2 (ETCO2) was measured at various time intervals before and after pneumo-peritoneum and head down. Ventilatory parameters were kept fixed after baseline setting. Those requiring any change were excluded. Pearson's coefficient was used for correlation and ANOVA for trend of parameters at different time intervals (P value <0.05 was considered significant). Results: Baseline cuff pressure after manual inflation was 46.2 ± 17.4 cm H2O. Significant correlation was observed between change in cuff pressure and increase in peak airway pressure at the end of the surgery (r = 0.4, P < 0.05). Serial measurements of ETT cuff pressure, peak airway pressure and ETCO2 were significantly increased compared to baseline (P < 0.05). Conclusion: Significant increases in ETT cuff pressure may be seen in robotic surgeries, with a positive correlation between change in cuff pressure and increase in airway pressures. Objective adjusted measurement of cuff pressure and airway pressures is recommended for such surgeries.

Efficacy of marine cyanobacterium Oxynema thaianum ALU PBC5 against multi drug resistant Gram negative pathogens.

AIM: Emergence of extended antibiotic resistance among several human bacterial pathogens often leads to the failure of existing antibiotics to treat bacterial infections worldwide. Hence, the present study is aimed to explore antibacterial activity of marine cyanobacterium against MDR pathogens. METHODS AND RESULTS: The cyanobacterial samples were collected and isolated from Thondi Palk Strait region. The isolate was subjected to polarity based solvent extraction and checked for their antibacterial activity against test bacterial pathogens. The active principles from chloroform extract of Oxynema thaianum (CEOT) were partially purified through thin layer chromatography (TLC). The active principle with highest activity was further characterized by FTIR, high performance liquid chromatography (HPLC) and gas chromatography mass spectrometry (GC-MS) analysis. Among the eight extracts tested, CEOT showed effective zone of clearance against ESBL producing Escherichia coli and Klebsiella pneumoniae in disc diffusion method. In TLC, all the purified five fractions were eluted and tested for their antibacterial activity against test pathogens. The third fraction showing maximum activity was subjected to HPLC analysis for checking its purity. In GC-MS analysis, 9-octadecenoic acid, methyl ester and hexadecanoic acid were identified as the major chemical compounds. CONCLUSION: Hence, the present study was concluded that O. thaianum ALU PBC5 is a promising agent to treat ESBL producing MDR bacterial pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the pioneer study on screening and isolation of bioactive compounds from the marine cyanobacteria against MDR pathogens such as E. coli and K. pneumoniae. Here, 9-octadecenoic acid, methyl ester and hexadecanoic acid were identified as the major chemical compounds through TLC, FTIR, HPLC and GC-MS. From this screen, we identified the bioactive compounds against ESBL producing multidrug resistant pathogens such as E. coli and K. pneumoniae.

A comparative study on effective cell disruption methods for lipid extraction from microalgae.

AIMS: To compare effective cell disruption methods for lipid extraction from fresh water microalgae. METHODS AND RESULTS: Chlorella sp., Nostoc sp. and Tolypothrix sp. were isolated from fresh water ponds in and around Gandhigram, Dindigul District, Tamilnadu, India, and used for lipid extraction. Different methods, including autoclaving, bead beating, microwave, sonication and a 10% NaCl solution treatments, were tested to identify the most effective cell disruption method. The total lipids from three microalgal species were extracted using a mixture of chloroform and methanol. Fatty acid composition was detected by gas chromatography (GC). Nostoc sp. and Tolypothrix sp. showed higher oleic acid content of 13.27 mg g(-1) dw and 17.75 mg g(-1) dw, respectively, whereas Chlorella sp. had high linoleic acid content of 17.61 mg g(-1) dw when the cells were disrupted using the sonication method. CONCLUSIONS: Finally, the sonication method was found to be the most applicable and efficient method of lipid extraction from microalgae. The highest lipid content was extracted from Chlorella sp. SIGNIFICANCE AND IMPACT OF THE STUDY: In biodiesel production from microalgae, lipid extraction is a crucial step and important as cell disruption comes in this step. Therefore, the appropriate cell disruption method and device is a key to increase the lipid extraction efficiency.

Thermodynamic database for protein-nucleic acid interactions (ProNIT).

MOTIVATION: Protein-nucleic acid interactions are fundamental to the regulation of gene expression. In order to elucidate the molecular mechanism of protein-nucleic acid recognition and analyze the gene regulation network, not only structural data but also quantitative binding data are necessary. Although there are structural databases for proteins and nucleic acids, there exists no database for their experimental binding data. Thus, we have developed a Thermodynamic Database for Protein-Nucleic Acid Interactions (ProNIT). RESULTS: We have collected experimentally observed binding data from the literature. ProNIT contains several important thermodynamic data for protein-nucleic acid binding, such as dissociation constant (K(d)), association constant (K(a)), Gibbs free energy change (DeltaG), enthalpy change (DeltaH), heat capacity change (DeltaC(p)), experimental conditions, structural information of proteins, nucleic acids and the complex, and literature information. These data are integrated into a relational database system together with structural and functional information to provide flexible searching facilities by using combinations of various terms and parameters. A www interface allows users to search for data based on various conditions, with different display and sorting options, and to visualize molecular structures and their interactions. AVAILABILITY: ProNIT is freely accessible at the URL http://www.rtc.riken.go.jp/jouhou/pronit/pronit.html.

Aminopyrimidine-carboxyl(ate) interactions in trimethoprim maleate, an antifolate drug.

In the title cocrystal, trimethoprim maleate [2,4-diamino-5-(3,4,5-trimethoxybenzyl)pyrimidin-1-ium maleate], C(14)H(19)N(4)O(3)(+).C(4)H(3)O(4)(-), the trimethoprim molecule is protonated at N1. The carboxyl group of the maleate ion makes a specific double hydrogen bond of type N-H.O with the 2-amino group and the protonated N1 atom of the trimethoprim cation which is similar to the carboxylate-trimethoprim cation interaction observed in the complex of dihydrofolate reductase with trimethoprim. The pyrimidine moieties of trimethoprim cations are centrosymmetrically paired through a pair of N-H.N hydrogen bonds involving the 4-amino group and the pyridinium N3 atom of a symmetry-related molecule. One of the O atoms at the maleate carboxylate group bridges the 2-amino and 4-amino groups on either side of the paired trimethoprim cations. The other O atom of the carboxylate group forms an intramolecular O-H.O hydrogen bond with the carboxyl group. These characteristic hydrogen bonds result in infinite two-dimensional aggregation of rings into a supramolecular ladder, which is further crosslinked through weak C-H.O interactions with methoxy groups of neighbouring trimethoprim molecules to form a layered structure.

Thermodynamic databases for proteins and protein-nucleic acid interactions.

Thermodynamic data regarding proteins and their interactions are important for understanding the mechanisms of protein folding, protein stability, and molecular recognition. Although there are several structural databases available for proteins and their complexes with other molecules, databases for experimental thermodynamic data on protein stability and interactions are rather scarce. Thus, we have developed two electronically accessible thermodynamic databases. ProTherm, Thermodynamic Database for Proteins and Mutants, contains numerical data of several thermodynamic parameters of protein stability, experimental methods and conditions, along with structural, functional, and literature information. ProNIT, Thermodynamic Database for Protein-Nucleic Acid Interactions, contains thermodynamic data for protein-nucleic acid binding, experimental conditions, structural information of proteins, nucleic acids and the complex, and literature information. These data have been incorporated into 3DinSight, an integrated database for structure, function, and properties of biomolecules. A WWW interface allows users to search for data based on various conditions, with different display and sorting options, and to visualize molecular structures and their interactions. These thermodynamic databases, together with structural databases, help researchers gain insight into the relationship among structure, function, and thermodynamics of proteins and their interactions, and will become useful resources for studying proteins in the postgenomic era.

ProTherm, version 2.0: thermodynamic database for proteins and mutants.

ProTherm 2.0 is the second release of the Thermo-dynamic Database for Proteins and Mutants that includes numerical data for several thermodynamic parameters, structural information, experimental methods and conditions, functional and literature information. The present release contains >5500 entries, an approximately 67% increase over the previous version. In addition, we have included information about reversibility of data, details about buffer and ion concentrations and the surrounding residues in space for all mutants. A WWW interface enables users to search data based on various conditions with different sorting options for outputs. Further, ProTherm has links with other structural and literature databases, and the mutation sites and surrounding residues are automatically mapped on the structures and can be directly viewed through 3DinSight developed in our laboratory. The ProTherm database is freely available through the WWW at http://www.rtc.riken.go.jp/protherm.html