Incentive spirometry inspiratory capacity changes and predictors after open heart surgery: a 5-day prospective study.

INTRODUCTION: Incentive spirometry (IS) is commonly used for increasing postoperative IS inspiratory capacity (ISIC) after open heart surgery (OHS). However, little is known about the serial changes in ISIC and their predictive factors. OBJECTIVE: The aim of this study is to identify the postoperative ISIC changes relative to preoperative ISIC after OHS, and determine their predictors, including patient characteristics factors and IS performance parameters such as inspiration volumes (ISv) and frequencies (ISf). METHODS: This is a prospective study with blinding procedures involving 95 OHS patients, aged 52.8±11.5 years, whose ISIC was measured preoperatively (PreopISIC) until fifth postoperative day (POD), while ISv and ISf monitored with an electronic device from POD1-POD4. Regression models were used to identify predictors of POD1 ISIC, POD2- POD5 ISIC increments, and the odds of attaining PreopISIC by POD5. RESULTS: The ISIC reduced to 41% on POD1, increasing thereafter to 57%, 75%, 91%, and 106% from POD2-POD5 respectively. Higher PreopISIC (B=-0.01) significantly predicted lower POD1 ISIC, and, together with hyperlipedemia (B=11.52), which significantly predicted higher POD1 ISIC, explained 13% of variance. ISv at relative percentages of PreopISIC from POD1-POD4 (BPOD1=0.60, BPOD2=0.56, BPOD3=0.49, BPOD4=0.50) significantly predicted ISIC of subsequent PODs with variances at 23%, 24%, 17% and 25% respectively, but no association was elicited for ISf. IS performance findings facilitated proposal of a postoperative IS therapy target guideline. Higher ISv (B=0.05) also increased odds of patients recovering to preoperative ISIC on POD5 while higher PreopISIC (B=- 0.002), pain (B=-0.72) and being of Indian race (B=-1.73) decreased its odds. CONCLUSION: ISv appears integral to IS therapy efficacy after OHS and the proposed therapy targets need further verification through randomized controlled trials.

Specific mutations induced by triplex-forming oligonucleotides in mice.

Triplex-forming oligonucleotides (TFOs) recognize and bind to specific duplex DNA sequences and have been used extensively to modify gene function in cells. Although germ line mutations can be incorporated by means of embryonic stem cell technology, little progress has been made toward introducing mutations in somatic cells of living organisms. Here we demonstrate that TFOs can induce mutations at specific genomic sites in somatic cells of adult mice. Mutation detection was facilitated by the use of transgenic mice bearing chromosomal copies of the supF and cII reporter genes. Mice treated with a supF-targeted TFO displayed about fivefold greater mutation frequencies in the supF gene compared with mice treated with a scrambled sequence control oligomer. No mutagenesis was detected in the control gene (cII) with either oligonucleotide. These results demonstrate that site-specific, TFO-directed genome modification can be accomplished in intact animals.

Degree of conversion and residual stress of preheated and room-temperature composites.

The aim of this study was to determine the degree of conversion and residual stress of resin composite preheated to different temperatures and to compare it to room-temperature composite. The composite resin was preheated to 40 degrees C, 50 degrees C, and 60 degrees C and packed into brass rings and light-cured. The degree of conversion and residual stress were analysed using Fourier transform infra-red spectroscopy and X-ray diffraction, respectively. The results obtained were tabulated and statistically analyzed using Kruskal-Wallis test and Tukey's honestly significantly different test. The results showed significant increase in the degree of conversion and residual stress with increase in preheating temperature.

Diminished DNA repair and elevated mutagenesis in mammalian cells exposed to hypoxia and low pH.

The tumor microenvironment is characterized by regions of fluctuating and chronic hypoxia, low pH, and nutrient deprivation. It has been proposed that this unique tissue environment itself may constitute a major cause of the genetic instability seen in cancer. To investigate possible mechanisms by which the tumor microenvironment might contribute to genetic instability, we asked whether the conditions found in solid tumors could influence cellular repair of DNA damage. Using an assay for repair based on host cell reactivation of UV-damaged plasmid DNA, cells exposed to hypoxia and low pH were found to have a diminished capacity for DNA repair compared with control cells grown under standard culture conditions. In addition, cells cultured under hypoxia at pH 6.5 immediately after UV irradiation had elevated levels of induced mutagenesis compared with those maintained in standard growth conditions. Taken together, the results suggest that cellular repair functions may be impaired under the conditions of the tumor microenvironment, causing hypermutability to DNA damage. This alteration in repair capacity may constitute an important mechanism underlying the genetic instability of cancer cells in vivo.

Hypermutability to ionizing radiation in mismatch repair-deficient, Pms2 knockout mice.

DNA mismatch repair (MMR) has been shown to play a role in the cytotoxicity of ionizing radiation (IR), as cell lines established from MMR-deficient mice exhibit higher clonogenic survival after IR than do cell lines from wild-type littermates. To test whether this tolerance phenotype would render MMR-deficient animals hypermutable to IR, we compared IR mutagenesis of Pms2-deficient versus wild-type transgenic mice carrying a lambda shuttle vector for mutation detection. In Pms2 nullizygous animals, the mutation frequency in the supFG1 reporter gene was increased from 210 x 10(-5) in untreated animals to 734 x 10(-5) after 6 Gy of IR (an increase of 524 mutants per 10(5)), whereas the frequency in wild-type mice increased from 1.9 x 10(-5) to 10.2 x 10(-5) (an increase of only 8.3 mutants per 10(5)). Similarly, when the lambda cII gene was used as a reporter, the mutation frequency in nullizygous mice was increased from 16.3 x 10(-5) to 42.3 x 10(-5) after IR (an increase of 26.0 x 10(-5)), whereas the frequency in wild-type mice increased from 2.4 x 10(-5) to 9.4 x 10(-5) (an increase of only 7.0 x 10(-5)). The pattern of IR-induced mutations in the MMR-deficient animals was notable for single bp deletions and insertions in mononucleotide repeat sequences, along with a slight increase in transversions. Overall, these results suggest that MMR-deficiency confers hypermutability to IR, and that much of this hypermutability can be attributed to induced instability of simple sequence repeats. Hence, MMR influences not only the survival but also the mutability of cells in response to IR.

Ionizing radiation-induced apoptosis via separate Pms2- and p53-dependent pathways.

The cytotoxicity of ionizing radiation (IR) has been associated with both the p53 pathway and with DNA mismatch repair (MMR). p53 mediates cell cycle arrest and apoptosis in response to X-ray damage, whereas the MMR complex is thought to recognize damaged bases and initiate a signal transduction pathway that can include phosphorylation of p53. To determine whether p53 and MMR mediate X-ray cytotoxicity via the same pathway, mice with targeted disruptions in either the p53 gene or the MutL homologue MMR gene Pms2 were interbred and primary fibroblasts were established from the progeny with genotypes of either wild type, p53 null, Pms2 null, or double null. Cells with either p53 or Pms2 separately disrupted showed reduced levels of apoptosis after IR in comparison with wild type, but the double null cells showed even lower levels, consistent with nonoverlapping roles for p53 and PMS2 in the X-ray response. In transformed cell lines established from the primary cells at early passage, similar differences in the apoptotic response to IR were seen, and clonogenic survival assays following low dose rate IR further showed that nullizygosity for Pms2 confers increased survival on cells in both wild-type and p53 null backgrounds. These results indicate that both p53 and MMR contribute to X-ray-induced apoptosis and that the role of MMR in the cytotoxicity of IR does not depend on p53.

Insulin-like growth factor-I receptor overexpression mediates cellular radioresistance and local breast cancer recurrence after lumpectomy and radiation.

The insulin-like growth factor-I receptor (IGF-IR) plays a critical role in cell growth regulation and transformation. The radiosensitivity of NIH 3T3 fibroblasts overexpressing either wild-type or mutant IGF-IR was examined. High levels of wild-type IGF-IR conferred radioresistance, and mutational analysis revealed that this effect correlated with the transforming capacity but not the mitogenic activity of the receptor. The radioresistant phenotype was reversed when the cells were incubated with antisense oligonucleotides targeted to IGF-IR mRNA, demonstrating that IGF-IR directly influences radioresistance. The clinical significance of these findings was examined in an immunohistochemical analysis of primary breast tumors, revealing that high levels of IGF-IR in tumor samples were highly correlated with ipsilateral breast tumor recurrence (IBTR) following lumpectomy and radiation therapy (P = 0.001). Subgroup analysis revealed that, for early breast tumor relapses (within 4 years of initial breast tumor diagnosis), elevated levels of IGF-IR were strongly associated with IBTR (P = 0.004) but IGF-IR expression was not prognostic for IBTR from breast cancer patients with late relapses (P was not significant). These studies provide evidence for the influence of IGF-IR on cellular radioresistance and response to therapy and raise the possibility that the radiocurability of selected tumors may be improved by pharmaceutical strategies directed toward the IGF-IR.

Role of DNA mismatch repair in the cytotoxicity of ionizing radiation.

The DNA mismatch repair (MMR) system in mammalian cells not only serves to correct base mispairs and other replication errors, but it also influences the cellular response to certain forms of DNA damage. Cells that are deficient in MMR are relatively resistant to alkylation damage because, in wild-type cells, the MMR system is thought to promote toxicity via futile repair of alkylated mispairs. Conversely, MMR-deficient cells are sensitive to UV light, possibly due to the requirement for MMR factors in transcription-coupled repair of active genes. MMR deficiency has been associated with familial and sporadic carcinomas of the colon and other sites, and so, we sought to determine the influence of MMR status on cellular response to ionizing radiation, an agent commonly used for cancer therapy. Fibroblast cell lines were established from transgenic mice carrying targeted disruptions of one of three MMR genes in mammalian cells: Pms2, Mlh1, or Msh2. In comparison to wild-type cell lines from related mice, the Pms2-, Mlh1-, or Msh2-nullizygous cell lines were found to exhibit higher levels of clonogenic survival following exposure to ionizing radiation. Because ionizing radiation generates a variety of lesions in DNA, the differences in survival may reflect a role for MMR in processing a subset of these lesions, such as damaged bases. These results both identify a new class of DNA-damaging agents whose effects are modulated by the MMR system and may help to elucidate pathways of radiation response in cancer cells.

Prevalence of periradicular radiolucencies and its association with the quality of root canal procedures and coronal restorations in an adult urban Indian population.

AIMS: The aim of this cross-sectional study was to determine the prevalence of periradicular radiolucencies (PR) from an urban adult Indian population and to investigate the quality of root canal procedures and coronal restorations and their association with prevalence of PR in root-filled teeth. SETTINGS AND DESIGN: Cross-sectional study. MATERIAL AND METHODS: A total of 1,340 subjects (18+ years of age) who reported for non-emergency dental care to 5 different dental care centers had their panoramic radiographs taken during the period from January to December 2013. The periradicular status of 30,098 teeth in these radiographs was evaluated using the Periapical Index Score (PAI). The assessment of the technical quality of the procedure was evaluated based on the criteria of root canal filling length and quality of coronal restoration. STATISTICAL ANALYSIS USED: The data was analyzed statistically by chi-squared test and odds ratio. RESULTS: PR was found in 65% of subjects (n = 865) and 5.8% (n = 1,759) of the 30,098 teeth evaluated (4.30% untreated teeth and 1.53% were root-filled teeth). In all, 4.1% of the teeth (n = 1,234) had some filling material in the root canal(s) and the prevalence of PR in these root-filled teeth was 37.4%, while the remaining 62.6% of root canal-filled teeth showed no evidence of PR. PR occurred significantly more often in teeth where root canal filling was filled more than 2 mm short of radiographic apex or when root filling extruded through the apex. CONCLUSIONS: The prevalence of PR in teeth with untreated root canals in India is 4.30%, which is more than twice the weighted world average, while the prevalence of root-filled teeth (4.1%) is lower than the world average (9.6%). The prevalence of PR in root-filled teeth in India is comparable to that in other populations. Inadequate root canal treatment and poor quality of coronal restoration were associated with increased prevalence of PR.

Ketamine inhibition of ligand binding to cholinergic receptors and ion channels.

Ketamine inhibited the binding of [3H]perhydrohistrionicotoxin and [3H]phencyclidine to the ion channel associated with Torpedo acetylcholine receptors with ID50 values between 11 and 84 micro M, but had not effect on [3H]acetylcholine or [3H]d-tubocurarine binding to the receptor itself. Ketamine's affinity for the ion channel was increased 3-5 fold by receptor agonists. Ketamine also inhibited muscarinic cholinergic receptors with ID50 between 28 and 38 micro M. These results are consistent with biophysical evidence that ketamine interferes with neuromuscular transmission through blockade of the ion channel.

Tissue specificity of spontaneous point mutations in lambda supF transgenic mice.

Transgenic mice carrying multiple copies of a recoverable lambda phage shuttle vector carrying the supF mutation reporter gene (lambda supF) were constructed for the purpose of studying mutagenesis in a whole animal. Spontaneous mutations in rescued supF target genes from mouse liver and skin were analyzed. The mutation frequency was similar in both tissues (in the range of 2 x 10(-5)), but the spectrum of point mutations was distinct, with transitions common in the skin and transversions more prominent in the liver (P = 0.01). These results may help to elucidate pathways of endogenous mutagenesis in vivo, and they illustrate potentially important tissue-specific differences in genetic instability.

Receptor--ion channel interactions in Torpedo electric organ: influence of thiol group modification.

The influence of sulfhydryl and disulfide reagents on nicotinic cholinergic receptors and ion channels and their interactions was investigated using specific probes for receptor and channel binding sites in electric organs from Torpedo californica. N-ethylmaleimide, a sulfhydryl alkylating agent, did not alter receptor or ion channel binding, or receptor-mediated ion channel binding activation or desensitization. Alteration of receptor--ion channel coupling produced by treatment with an organic sulfhydryl, dithiothreitol, could be accounted for on the basis of decreases in receptor affinity for agonists. These changes were reversed by exposure to an oxidizing agent. Following reduction by dithiothreitol, N-ethylmaleimide treatment produced large decreases in the extent and affinity of both receptor and channel binding. No evidence for a direct role of thiol groups in ion channel function was obtained.

Sensitive high-performance liquid chromatography method for the determination of low levels of perchlorate in biological samples.

A rapid and sensitive high-performance liquid chromatography (HPLC) method was developed to detect perchlorate in tissues of male and female rats, both pregnant and lactating (including milk) after administration of perchlorate. Supernatants of ethanol precipitated rat fluids and tissues were evaporated to dryness under nitrogen and reconstituted in deionized water. Reconstituted samples were injected into HPLC system coupled with conductivity detection. Isocratic separation of perchlorate was achieved using an anion-exchange column with sodium hydroxide as mobile phase and a conductivity detector. In this method, perchlorate showed a linear response range from 5 to 100 ng/ml. The lower detection limits for perchlorate in fluids and tissues of rats were 3-6 ng/ml and 0.007-0.7 mg/kg, respectively. The described method has the unique advantage over the existing methods of determining low traces of perchlorate in different biological matrices without complex sample preparation.

Perfluorodecanoic acid, a peroxisome proliferator, activates phospholipase C, inhibits CTP:phosphocholine cytidylyltransferase, and elevates diacylglycerol in rat liver.

Perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) are peroxisome proliferators that cause hepatotoxicity in rodents. This study shows that PFDA activates liver phospholipase C (PLC) and inhibits CTP:phosphocholine cytidylyltransferase (CT). PLC cytosolic and microsomal activities were increased 1.4- and 1.7-fold, respectively. CT activates were decreased to 58% (cytosol) and 36% (microsome) of control values. PFDA also caused a threefold increase in liver diacylglycerol (DAG) concentration. PFOA had no effect on the enzyme activities or DAG concentration. Together with previous results, these data suggest that PFDA activates a phosphatidylcholine-specific PLC causing an increase in liver phosphocholine and DAG. These effects are discussed in relation to cellular signalling processes that may provide a mechanism for PFDA-induced hepatotoxicity.

Repeated exposure of rats to JP-4 vapor induces changes in neurobehavioral capacity and 5-HT/5-HIAA levels.

Thirty-two Sprague-Dawley rats were exposed for 6 h/d for 14 consecutive days to JP-4 jet fuel vapor (2 mg/L) or room air control conditions. Following a 14- or 60-d recovery period, rats completed a battery of 8 tests selected from the Navy Neurobehavioral Toxicity Assessment Battery (NTAB) to evaluate changes in performance capacity. Exposure to JP-4 vapor resulted in significant changes in neurobehavioral capacity on several tests that varied as a function of the duration of the recovery period. Rats were evaluated for major neurotransmitter and metabolite levels in five brain regions and in the blood serum. Levels of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were shown to be significantly elevated in several brain regions as well as in the blood serum in the vapor-exposed groups. Results of the rat study are compared to previously reported neurobehavioral evaluations of European manufacturing personnel exposed chronically to jet fuel vapor.

Superimposition of a mechanical valve on an impacted aortic bioprosthesis.

During reoperation for replacement of a regurgitant aortic bioprosthesis (a 23-mm bovine pericardial valve), it was judged that total removal of the valve would be difficult, and hazardous to the patient. Therefore, its leaflets were excised and its sewing ring left in situ. A 21-mm Carbomedics bileaflet mechanical valve was sutured to the bioprosthetic sewing ring and implanted in the orifice of the bioprosthesis, resulting in excellent hemodynamic performance. We report this new technique to illustrate its feasibility, safety, and efficiency, as an alternative to complete removal of defective prostheses in the aortic position.

Assessment of malnutrition in alcoholic and non alcoholic cirrhotics.

OBJECTIVE: To study the nutritional status in patients with chronic liver disease using anthropometric techniques. METHODS: A total of 60 cirrhotic patients (30 Alcoholic (AC), 30 Non-alcoholic (NAC) and 30 control (CO) subjects were studied. Nutritional status was assessed using anthropometric measurements such as stature, body weight, body mass index, (BMI), skinfold thickness measurements and mid upper arm muscle circumference. Serum protein, serum albumin and globulin were measured. RESULTS: The skinfold thicknesses were significantly lower in NAC group of patients. In contrast the AC group of patients showed significantly lower mid upper arm muscle circumference values. Both groups of cirrhotic patients showed significantly lower total serum protein and serum albumin levels. CONCLUSION: Body fat is relatively more affected in NAC group of patients and muscle mass is more affected in AC group of patients.

Influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate: An in vitro study.

AIMS: The aim of this study was to assess the influence of temperature and concentration on the dynamic viscosity of sodium hypochlorite in comparison with 17% EDTA and 2% chlorhexidine gluconate. SETTINGS AND DESIGN: In vitro. MATERIALS AND METHODS: Dynamic viscosity measurements of sodium hypochlorite [NaOCl (5.25%, 2.6%, 1.25%)], EDTA (17%), and chlorhexidine gluconate [CHX, 2%] were measured using a rotational digital viscometer at room temperature (25°C). The influence of temperature (45°C, 60°C) and concentration (5.25%, 2.6%, and 1.25%) on the dynamic viscosity of NaOCl was also evaluated. The measurements were performed using a circulating water bath calibrated with a thermostat, and the dynamic viscosity measurements were noted in Centipoise (Cps). STATISTICAL ANALYSIS USED: The tests used for the statistical analysis were Kolmogorov-Smirnov and Shapiro Wilk tests, one-way ANOVA, and independent sample t-test. RESULTS: Viscosity statistically increased with NaOCl concentration and decreased with increasing temperature. Amongst the tested NaOCl groups, 5.25% NaOCl at room temperature was significantly the most viscous (µ =1.5300 Cps) while 1.25% NaOCl at 60°C was significantly the least viscous (µ =1.1800 Cps). CONCLUSIONS: 5.25% NaOCl and 17% EDTA are significantly viscous at room temperature. Elevating the temperature of 1.25% NaOCl to 60°C significantly reduces the viscosity of the NaOCl.

Functional characterization of rare variants in human dopamine receptor D4 gene by genotype-phenotype correlations.

Next generation sequencing technologies have facilitated a notable shift from common disease common variant hypothesis to common disease rare variant, as also witnessed in recent literature on schizophrenia. Dopamine receptor D4 (DRD4), a G-protein-coupled receptor is associated with psychiatric disorders and has high affinity for atypical antipsychotic clozapine. We investigated the functional role of rare genetic variants in DRD4 which may have implications for translational medicine. CHO-K1 cells independently expressing four rare non-synonymous variants of DRD4 namely R237L, A281P, S284G located in the third cytosolic loop and V194G, located in the fifth transmembrane domain were generated. Their genotype-phenotype correlations were evaluated using [³H]spiperone binding, G-protein activation and molecular dynamics-simulation studies. A281P and S284G were functionally similar to wildtype (WT). With R237L, potency of dopamine and quinpirole reduced ∼sixfold and threefold respectively compared to WT; [³H]spiperone binding studies showed a reduction in total number of binding sites (∼40%) but not binding affinity, in silico docking studies revealed that binding of both dopamine and spiperone to R237L was structurally similar to WT. Of note, V194G variant failed to inhibit forskolin-stimulated adenylate cyclase activity and phosphorylate extracellular signal-regulated kinase; showed significant reduction in binding affinity (K(d)=2.16 nM) and total number of binding sites (∼66%) compared to WT in [³H]spiperone binding studies; and ligand docking studies showed that binding of dopamine and spiperone is superficial due to probable structural alteration. Transmembrane variant V194G in DRD4.4 results in functional alteration warranting continuing functional analysis of rare variants.

Irrigation protocol among endodontic faculty and post-graduate students in dental colleges of India: A survey.

BACKGROUND: Irrigation protocol is the most critical step during the disinfection of an infected root canal system. AIM: The purpose of this study was to determine the root canal irrigation trends being practiced among the endodontic teaching faculty and post-graduate students in the dental colleges present in India. MATERIALS AND METHODS: A postal invitation to participate in this national survey was sent to the Department of Conservative Dentistry and Endodontic of 294 Dental Colleges present in India. A total of 2389 forms were successfully delivered out of which 794 duly filled forms were received back. Survey participants were asked about their irrigant selection, irrigant concentration, smear layer removal protocol, and use of adjuncts during irrigation. RESULTS: This survey elicited a positive response rate of 33.23%. Our data indicated that 92.8% of respondents use sodium hypochlorite (NaOCl) as the primary endodontic irrigant, with 26 gauge needle being most preferred for syringe irrigation, with 49.3% of them using it at a concentration of 2.6-4.0%. 68% of our respondents aim to remove the smear layer during the endodontic treatment while 47% reported using ultrasonic activation as an adjunct during their irrigation protocol. CONCLUSIONS: The findings of this survey are that the majority of teaching institutions in India are employing NaOCl (2.6-4.0%) as the primary endodontic irrigant. The concept of smear layer removal is high (68%), and there is a general trend (78%) to modify the irrigation protocol according to the status of the pulp, status of the periapex and in retreatment cases.