Massive haemorrhage during anterior cervical fusion attributable to a tear at the junction of the subclavian and internal jugular veins.
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Female↗
Biomedical subjects
R Prabhu
Publications and source records attributed to R Prabhu.
Increases in sexually transmitted infections and sexual risk behaviour without a concurrent increase in HIV incidence among men who have sex with men in San Francisco: a suggestion of HIV serosorting?
BACKGROUND: Sexually transmitted infections (STI) and unprotected anal intercourse (UAI) have been increasing among men who have sex with men (MSM) in San Francisco. However, HIV incidence has stabilised. OBJECTIVES: To describe recent trends in sexual risk behaviour, STI, and HIV incidence among MSM in San Francisco and to assess whether increases in HIV serosorting (that is, selective unprotected sex with partners of the same HIV status) may contribute to preventing further expansion of the epidemic. METHODS: The study applies an ecological approach and follows the principles of second generation HIV surveillance. Temporal trends in biological and behavioural measures among MSM were assessed using multiple pre-existing DATA SOURCES: STI case reporting, prevention outreach programmatic data, and voluntary HIV counselling and testing data. RESULTS: Reported STI cases among MSM rose from 1998 through 2004, although the rate of increase slowed between 2002 and 2004. Rectal gonorrhoea cases increased from 157 to 389 while early syphilis increased from nine to 492. UAI increased overall from 1998 to 2004 (p<0.001) in community based surveys; however, UAI with partners of unknown HIV serostatus decreased overall (p<0.001) among HIV negative MSM, and among HIV positive MSM it declined from 30.7% in 2001 to a low of 21.0% in 2004 (p<0.001). Any UAI, receptive UAI, and insertive UAI with a known HIV positive partner decreased overall from 1998 to 2004 (p<0.001) among MSM seeking anonymous HIV testing and at the STI clinic testing programme. HIV incidence using the serological testing algorithm for recent HIV seroconversion (STARHS) peaked in 1999 at 4.1% at the anonymous testing sites and 4.8% at the STI clinic voluntary testing programme, with rates levelling off through 2004. CONCLUSIONS: HIV incidence among MSM appears to have stabilised at a plateau following several years of resurgence. Increases in the selection of sexual partners of concordant HIV serostatus may be contributing to the stabilisation of the epidemic. However, current incidence rates of STI and HIV remain high. Moreover, a strategy of risk reduction by HIV serosorting can be severely limited by imperfect knowledge of one's own and one's partners' serostatus.
Adult↗
Surgical stress-induced alterations in retinoid metabolism in the small intestine: role of oxygen free radicals.
Oxidative stress in the small intestine can result in altered cell proliferation, migration, and differentiation of villus-crypt cells. Retinoid metabolism is recognized as an important mediator of cellular differentiation in the intestine. This study examined the effect of oxidative stress in retinoid metabolism in a surgical stress model. Surgical stress was performed by handling the intestine as done during laparotomy. Villus-crypt cells were isolated at different time periods and various retinoid concentrations in the cell homogenate and the retinoic acid forming enzymes were quantitated using HPLC. Surgical stress resulted in altered retinoid levels in various cell populations in the small intestine at 1 and 12h. The activity of alkaline phosphatase and retinal oxidase was also altered at these time points and all these changes were prevented by inhibiting superoxide generation using xanthine oxidase inhibitor, allopurinol. These studies suggest that alterations seen in enterocytes during surgical stress may be mediated by changes in retinoid metabolism.
Aldehyde Oxidoreductases↗
Altered glycosylation of surfactant and brush border membrane of the small intestine in response to surgical manipulation.
BACKGROUND: Surgical stress can lead to bacterial translocation from the intestine into systemic circulation. Adherence of bacteria onto the glycoconjugates of the brush border membrane (BBM) and surfactant coat (SLP) of the mucosal cells is the first step in the translocation of luminal bacteria. Our earlier study showed that surgical manipulation of the intestine results in oxidative stress leading to structural and functional alterations in the mucosa. This study looks at the effect of surgical manipulation on the glycoconjugate alterations of SLP and BBM. MATERIALS AND METHODS: SLP and BBM were isolated from control and after surgical manipulation and the sugar composition was analyzed. Bacterial adherence using E. coli isolated from cecum was compared after coating microtiter plates with SLP or BBM isolated from control and after surgical manipulation. RESULTS: An increase in various sugars was seen after surgical manipulation both in SLP and BBM and this increase was maximum at 12 h after surgery. These alterations increased bacterial adherence onto SLP and BBM. Inhibiting superoxide generation by allopurinol treatment prior to surgical manipulation prevented glycosylation alteration and bacterial adherence. CONCLUSION: Surgical manipulation results in altered glycoconjugates of SLP and BBM which leads to increased bacterial adherence. These alterations are probably brought about by oxygen-free radicals. This is clinically significant because postsurgical complications such as sepsis may be brought about by altered glycosylation.
Allopurinol↗
Protein thiol oxidation and lipid peroxidation in patients with uraemia.
BACKGROUND: Patients with uraemia are exposed to increased oxidative stress. In this study, a series of oxidative stress markers were measured in patients with chronic renal failure (CRF) and patients with CRF on haemodialysis (HD) compared to normal controls to establish whether there is enhanced oxidative stress on HD therapy in uraemic subjects. METHODS: Protein thiol oxidation, lipid hydroperoxides, albumin and uric acid concentrations were estimated in patients receiving HD and patients with CRF and compared with those in healthy controls. RESULTS: There was a significant decrease in the level of protein thiols in CRF (p = 0.0001) and HD patients (p = 0.0001) compared with that in controls. Lipid hydroperoxides were significantly higher in CRF (p = 0.026) and HD patients (p = 0.003) than in controls. However, there was no significant difference in protein thiols and lipid hydroperoxides between CRF and HD patients. Serum protein thiols correlated negatively with lipid hydroperoxides and positively with serum albumin. CONCLUSIONS: These findings suggest that both CRF and HD patients have increased plasma protein oxidation and lipid peroxidation. However, HD therapy per se did not contribute to oxidative stress already present in uraemia. Owing to the variability in lipid peroxidation products as markers of oxidative stress and the vital role played by thiol antioxidants in the biological system, it is suggested that protein thiol oxidation may be a better marker of oxidative stress.
Adult↗
Stem-loop structures II-IV of the 5' untranslated sequences are required for the expression of the full-length hepatitis C virus genome.
The 5' and 3' untranslated regions (UTR) of the hepatitis C virus (HCV) genome contain stem-loop structures, which are important in viral gene expression and replication. In this study, the functional roles of the predicted stem-loop structures of HCV 5' UTR and 3' UTR in viral gene expression were examined using a chimeric clone of full-length HCV genomic cDNA clone and the gene for green fluorescent protein (GFP). High level expression of the HCV-GFP chimera in Huh-7 cells was accomplished by using a replication defective adenovirus that expresses T7 RNA polymerase and transcription plasmid containing full-length HCV-GFP chimera under the control of a T7 promoter. The HCV-GFP clone, with deletion of stem-loop I, expressed proteins in transfected Huh-7 cells at comparable levels to the wild type HCV clone. Other mutations of the 5' UTR, which either deleted or altered the base pairing of stem-loops II to IV, completely abolished the expression of HCV-GFP chimera. In contrast, deletion of 3' UTR sequences had no effect on HCV protein expression. These findings suggest that the stem-loop structures II to IV of HCV 5' UTR are necessary for protein expression, but that stem loop I is dispensable for protein translation. The stem-loop structures of 3' UTR of HCV genome appear to have no direct role in viral gene expression.
3' Untranslated Regions↗
Effect of oxidants on small intestinal brush border membranes and colonic apical membranes--a comparative study.
This study compares composition of the rat small intestinal brush border membranes (BBM) and colonic apical membranes (CAM) and their susceptibility to in vitro exposure to various oxidants. Differences were observed between BBM and CAM in their lipid composition, sugar content, alkaline phosphatase (ALP) activity and cholesterol/phospholipid ratio. BBM and CAM were exposed to superoxide generated by xanthine+xanthine oxidase (X-XO) or peroxides such as tertiary butyl hydroperoxide (tBuOOH) and hydrogen peroxide (H(2)O(2)) and alterations in ALP activity, peroxidation parameters and membrane lipids were analyzed. Exposure of BBM and CAM to superoxide resulted in decrease in ALP activity and increase in peroxidation parameters such as protein carbonyl content, malondialdehyde and conjugated diene. Superoxide exposure also resulted in lipid alterations specifically in certain phospholipids. These alterations were prevented either by superoxide dismutase or by allopurinol. Peroxides did not have any significant effect. These results suggest that both BBM and CAM are susceptible to superoxide, which can bring about peroxidation and degradation of membrane lipids specifically, certain phospholipids.
Alkaline Phosphatase↗
Heat preconditioning attenuates oxygen free radical-mediated alterations in the intestinal brush border membrane induced by surgical manipulation.
BACKGROUND: The intestine is highly susceptible to free radical-induced damage and our earlier work has shown that surgical manipulation of the intestine results in generation of oxygen free radicals and mucosal damage along with alterations in the brush border membrane (BBM). Heat preconditioning is known to offer protection against various stresses including oxidative stress and this study looked at the effect of heat preconditioning on the intestinal BBM alterations following surgical manipulation. METHODS: Control and rats heat preconditioned were subjected to surgical manipulation by opening the abdominal wall and handling the intestine. BBM were isolated from the intestine and structural and functional alterations to these membranes were assessed. RESULTS: Surgical manipulation resulted in oxidative stress suggested by a decrease in alkaline phosphatase activity and alpha-tocopherol content, accompanied by an increase in lipid peroxidation. A decrease in glucose transport by the isolated BBM vesicles suggested functional impairment. Surgical manipulation resulted in phospholipid degradation with generation of arachidonic acid along with appearance of cPLA(2) in the membrane. These changes were prevented by heat preconditioning of the animal prior to surgical manipulation. CONCLUSION: These results suggest that heat preconditioning offers protection from damage to the intestinal BBM following surgical manipulation and mild whole body hyperthermia might prevent postsurgical complications.
Alkaline Phosphatase↗
A novel method of preparation of small intestinal brush border membrane vesicles by polyethylene glycol precipitation.
A novel method of brush border membrane vesicle (BBMV) preparation from the small intestinal mucosa using polyethylene glycol (PEG) precipitation has been presented. This preparation is compared with calcium-precipitated BBMVs in marker enzyme enrichment, contamination by other subcellular membranes, transport of glucose, and lipid composition. PEG-precipitated BBMVs are comparable with calcium-precipitated membranes in all parameters except lipid composition and thiol content. PEG-precipitated membranes have more phosphatidylcholine and phosphatidylethanolamine and less lysophosphatidylcholine and lysophosphatidylethanolamine as compared to calcium-precipitated membranes. Diacylglycerol and triacylglycerol content are also high in PEG-precipitated membranes. Alteration in lipid composition indicate the possible activation of lipase and phospholipase by calcium during BBMV preparation, which is not seen in PEG precipitation. Thiol content is almost double in PEG-precipitated membranes as compared to calcium-precipitated membranes. These results indicate that PEG can be used for the preparation of BBMVs in native form from the intestine without any alteration in their structural components, and these membranes show comparable transport activity.
Alkaline Phosphatase↗
Effect of surgical manipulation of the rat intestine on enterocyte populations.
BACKGROUND: The intestine is susceptible to operations at remote locations, and the barrier function is altered during intestinal manipulation, leading to bacterial or endotoxin translocation into the systemic circulation. One of the mainstays for the maintenance of the integrity of the barrier function is epithelial cell proliferation and migration. The present study looked at the effect of gut manipulation after laparotomy on different cell populations of the intestinal epithelium. METHODS: Surgical manipulation of the gut was performed by opening the abdominal wall and handling the intestine, as is done during laparotomy. Villus and crypt cells were isolated at different time periods after gut manipulation, and mitochondria were prepared from isolated enterocytes. The effects of surgical manipulation on enterocytes and isolated mitochondria were studied. RESULTS: Mechanical manipulation of the gut resulted in alterations in the intestinal epithelium, as shown by decreased cell viability and yield in the crypt cells. The alterations were associated with actin reorganization, as well as with altered cell proliferation and adenosine deaminase activity. At the mitochondrial level, altered mitochondrial function, such as decreased respiratory control ratio, increased 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide reduction, and induction of permeability transition in the crypt cells, was observed. These alterations were maximal 1 hour after surgical manipulation and partially recovered to normal by 24 hours. CONCLUSIONS: Mechanical manipulation of the gut that occurs during any abdominal operation induces alterations in the intestine, both at the cellular and the subcellular levels. The crypt cells bear the brunt of the damage, and the reversibility of the damage is possibly brought about by increased proliferation and movement of the cells.
Actins↗
Surgical stress induces phospholipid degradation in the intestinal brush border membrane.
BACKGROUND: Surgical stress can lead to translocation of bacteria from the intestine into the systemic circulation. The intestinal brush border membrane (BBM) plays an important role in defense against such invasion by luminal bacteria and endotoxin. Our earlier work has shown the development of oxidative stress in the intestine after surgical stress and since the BBM is sensitive to free radical attack, this study examined the effect of surgical stress on the structure and function of intestinal BBM. METHODS: Intestinal BBM were isolated from control and after surgical stress and compared for structural and functional alterations. Surgical stress was also carried out following pretreatment with the xanthine oxidase inhibitor allopurinol or the nitric oxide donor l-arginine, to study the protection offered by these compounds. RESULTS: Surgical stress affected intestinal BBM structure as well as function. A decrease in alkaline phosphatase activity and alpha-tocopherol content, accompanied by an increase in lipid peroxidation, was seen. Surgical stress induced phospholipid degradation with generation of arachidonic acid. Functional impairment with a decrease in glucose transport ability was also seen. These changes are prevented by inhibition of xanthine oxidase by allopurinol pretreatment but not by NO. CONCLUSION: Surgical stress in the small intestine causes structural and functional alterations in the BBM through oxidative stress. This damage could affect gut barrier integrity and generation of arachidonic acid might mediate distal organ dysfunction.
Abdomen↗
Development of a methodology for selecting criteria and indicators of sustainable forest management: a case study on participatory assessment.
This paper describes an application of multiple criteria analysis (MCA) in assessing criteria and indicators adapted for a particular forest management unit. The methods include: ranking, rating, and pairwise comparisons. These methods were used in a participatory decision-making environment where a team representing various stakeholders and professionals used their expert opinions and judgements in assessing different criteria and indicators (C&I) on the one hand, and how suitable and applicable they are to a forest management unit on the other. A forest concession located in Kalimantan, Indonesia, was used as the site for the case study. Results from the study show that the multicriteria methods are effective tools that can be used as structured decision aids to evaluate, prioritize, and select sets of C&I for a particular forest management unit. Ranking and rating approaches can be used as a screening tool to develop an initial list of C&I. Pairwise comparison, on the other hand, can be used as a finer filter to further reduce the list. In addition to using these three MCA methods, the study also examines two commonly used group decision-making techniques, the Delphi method and the nominal group technique. Feedback received from the participants indicates that the methods are transparent, easy to implement, and provide a convenient environment for participatory decision-making.
Journal Article↗
Isolation of emetine resistant clones of Entamoeba histolytica by petri dish agar method.
Emetine resistant clones of Entamoeba histolytica strain HM1:IMSS were isolated by using petri dish agar method after mutation with ethyl-methanesulphonate. Two emetine resistant clones were obtained and both were resistant to emetine at a concentration of 24 micrograms/ml of emetine. The 50 per cent inhibitory concentration (IC50) for both emetine sensitive and resistant clones was 5 and 14 micrograms/ml respectively. The colony forming efficiency of E. histolytica strain HM1:IMSS varied from 44 to 54 per cent. This method is useful for isolating clones from different strains of the parasite for molecular and immunological studies.
Agar↗
Unusual tubercular abscesses in two elderly women.
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Abscess↗
Evaluation of a pulse oximeter during profound hypothermia. An assessment of the Biox 3700 during induction of hypothermia before cardiac surgery in paediatric patients.
The accuracy of the Ohmeda Biox 3700 pulse oximeter was evaluated in 10 paediatric patients, deliberately surface cooled to 25 degrees C in preparation for cardiac surgery, by comparing the arterial oxygen saturation results obtained from an Ohmeda Biox 3700 and a Radiometer OSM-2 Hemoximeter. Though there was a good correlation between the two series of results, the arterial oxygen saturation was over-estimated by the pulse oximeter compared to the OSM-2 Hemoximeter in the temperature range 36 degrees to 30 degrees C and under-estimated below 30 degrees C. These differences were greatest when the initial saturations were low.
Cardiac Surgical Procedures↗
Direct measurement of the energetics of association between myelin basic protein and phosphatidylserine vesicles.
A newly designed high-sensitivity isothermal reaction calorimetry system has been used to investigate the thermodynamics of the association between myelin basic protein and phosphatidylserine vesicles. This instrument has allowed us to measure directly the energetics of the protein-lipid interaction under various conditions. Above the phospholipid phase transition temperature the enthalpy of association is highly exothermic amounting to -160 kcal/mol of protein. Below the phospholipid phase transition temperature the enthalpy of association is exothermic at protein/lipid ratios smaller than 1/50 and endothermic at higher protein/lipid ratios. These studies indicate that the association of myelin basic protein to phosphatidylserine vesicles consists of at least two stages involving different types of binding. The first stage, at low protein/lipid ratios, involves a strong exothermic association of the protein to the membrane and the second, at high protein/lipid ratios, a weaker association probably involving attachment of the protein to the membrane surface only. In the gel phase the second binding stage is endothermic and appears to be correlated with the formation of large vesicle aggregates. This vesicle aggregation is a reversible process dependent upon the physical state of the membrane. The isothermal titration studies have been complemented with high-sensitivity differential scanning calorimetry experiments. It is shown that the dependence of the phospholipid transition enthalpy on the protein/lipid molar ratio can be expressed in terms of the different protein-membrane association enthalpies in the gel and fluid phases of the membrane.
Animals↗
Anaesthesia for extracorporeal shock wave lithotripsy.
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Anesthesia↗
Characterization of dihydrofolate reductase-related DNA and RNA from human KB cell subclones containing different amounts of enzyme.
The present study was aimed to characterize dihydrofolate reductase (DHFR)-related DNA and RNA in a series of human KB cell sublines and to further understand the mechanisms of DHFR regulation. We used two probes, one which could recognize the 5' flanking sequence (p5') of the human DHFR gene and one derived from mouse complementary DNA (pDHFR 26) which contains the coding sequence for DHFR, to identify the DHFR-related DNA and RNA. Our results revealed no major differences in DNA gene structure as the copy number increases. The recognizable fragments of DHFR gene were similar including the 5' flanking sequence upstream from the first exon. We observed that all DHFR mRNA species identified were present in the subclones. The content of cytoplasmic DHFR mRNA does not always correlate with the relative gene copy number in these cell lines. Furthermore, we were able to detect high-molecular-weight RNA related to DHFR which might be the precursors of the DHFR mRNAs. Finally, using different RNA extraction procedures, we observed that different patterns of cytoplasmic DHFR mRNA can be obtained, which is probably due to differential breakdown of RNA species during extraction procedures.
Base Sequence↗