A Method for the Measurement of Salivary Gland Function in Mice

Patients with Sjögren's syndrome, an autoimmune disease affecting the exocrine glands, develop salivary gland inflammation and have reduced saliva production. Similarly, saliva production is severely compromised in patients receiving radiation treatment for head and neck cancers. Rodent models, developed to mimic these clinical conditions, facilitate an understanding of the disease pathogenesis and allow for the development of new therapeutic strategies. Therefore, the ability to accurately, reproducibly, and repeatedly measure salivary gland function in animal models is critical. Building on procedures previously described in the literature, a method was developed that meets these criteria and was used to evaluate salivary gland function in mice. An additional advantage of this new method is that it is easily mastered, and has little inter-operator variation. Salivary gland function is evaluated as the amount (weight or volume) or rate (mL/min) of saliva produced in response to pilocarpine stimulation. The collected saliva is a good source for the analyses of protein content, immunoglobulin concentrations, and other biomolecules.

Intraoperative assessment of transient and persistent regional left ventricular wall motion abnormalities in patients undergoing coronary revascularization surgery using real time three-dimensional transesophageal echocardiography: A prospective observational study

OBJECTIVE

To evaluate the feasibility of intraoperative real time three-dimensional echocardiography (RT3DE) for identification and quantification of transient and persistent regional wall motion abnormalities (RWMAs) in patients with ischemic cardiomyopathy undergoing coronary artery bypass grafting (CABG).

DESIGN

A prospective observational study SETTING: Single-center study in an academic tertiary care hospital PARTICIPANTS: A series of 42 patients undergoing elective CABG over a 2-year period were included.

INTERVENTION

After induction of anesthesia, a comprehensive transesophageal echocardiography (TEE) examination was performed to evaluate regional wall motion using two-dimensional wall motion score index (WMSI) and RT3D echocardiographic parameters at three specific time points during the operative phase.

MEASUREMENTS AND MAIN RESULTS

The 3D assessment of LV function was based on the quantification of change in LV chamber volume over time from each segment excursion. Patients were divided into two groups and subgroups based on TEE findings. There was significant mechanical dyssynchrony in patients with RWMAs (WMSI > 1; systolic dyssynchrony index [SDI] = 7.0 ± 3.66) as compared to the patients having normal wall motion (WMSI = 1; SDI = 2.0 ± 0.95; P = .001). Patients with contractile dysfunction were found to have low values of segmental excursion and high values of negative excursion on parametric imaging. Persistent RWMAs due to hibernating myocardium showed significant resolution of mechanical dyssynchrony after revascularization. Parametric imaging could detect transient RWMAs due to stunning and graft dysfunction. Early activating segments (EAS) on "timing bull's-eye" may represent hypercontractile segments and may influence inotrope administration.

CONCLUSION

The RT3DE is a valuable modality for precise quantification of regional wall motion during revascularization procedure.

Structure and Gene Cluster of the K93 Capsular Polysaccharide of Acinetobacter baumannii B11911 Containing 5-N-Acetyl-7-N-[(R)-3-hydroxybutanoyl]pseudaminic Acid

Capsular polysaccharide (CPS) assigned to the K93 type was isolated from the bacterium Acinetobacter baumannii B11911 and studied by sugar analysis along with one- and two-dimensional ¹H and ¹³C NMR spectroscopy. The CPS was found to contain a derivative of pseudaminic acid, and the structure of the branched tetrasaccharide repeating unit was established. Genes in the KL93 capsule biosynthesis locus were annotated and found to be consistent with the CPS structure established. The K93 CPS has the α-d-Galp-(1→6)-β-d-Galp-(1→3)-d-GalpNAc trisaccharide fragment in common with the K14 CPS of Acinetobacter nosocomialis LUH 5541 and A. baumannii D46. It also shares the β-d-Galp-(1→3)-d-GalpNAc disaccharide fragment and the corresponding predicted Gal transferase Gtr5, as well as the initiating GalNAc-1-P transferase ItrA2, with a number of A. baumannii strains.

Molecular Mechanisms of Colistin Resistance in Klebsiella pneumoniae Causing Bacteremia from India-A First Report

Colistin has long been a reserve drug used for the treatment of carbapenem resistant Klebsiella pneumoniae. Carbapenem resistance in K. pneumoniae has been increasing and is as high as 44% in India. Although a reserve agent, with rise in rates of resistance to carbapenems, the usage of colistin has increased over the years leading to slow emergence of resistance. Colistin resistance is mainly mediated by the alteration in the LPS of bacterial outer membrane with the addition of L-Ara4-N and PEtN molecules. These alterations are mediated by mutations in several genes involved in lipidA modifications and most commonly mutations in mgrB gene has been reported. Recently there is emergence of plasmid mediated resistance due to mcr-1 and mcr-2 genes which poses a threat for the rapid global spread. This study aims at characterizing eight colistin resistant K. pneumoniae from bacteremia by whole genome sequencing. Eight K. pneumoniae were isolated from blood culture during 2013 and 2014 at the Department of Clinical Microbiology, Christian Medical College, India. Antimicrobial susceptibility testing was performed and minimum inhibitory concentration (MIC) was determined for colistin and polymyxin B by broth-micro dilution method. Whole genome sequencing was performed using Ion Torrent and the genome of all eight isolates was analyzed. The eight isolates were resistant to all the antimicrobials expect tigecycline. MIC of colistin and polymyxin B were ranged from 4 to 1024 μg/ml and 0.5 to 2048 μg/ml respectively. Multiple mutations were observed in the chromosomal genes involved in lipid A modifications. mcr-1 and mcr-2 gene was absent in all the isolates. The most significant were mutations in mgrB gene. Among the eight isolates, four, three and one were belonged to sequence types ST 231, ST14 and ST147 respectively. Seven isolates had bla_{OXA-48 like}, one co-expressed bla_NDM-1 and bla_{OXA-48 like} genes leading to carbapenem resistance. Overall, multiple numbers of alterations have been observed. This includes silent mutations, point mutations, insertions and/or deletions. Mutations in mgrB gene is responsible for resistance to colistin in this study. Due to emergence of resistance to reserve drugs, there is a need for combination therapies for carbapenem resistant K. pneumoniae and colistin must be judiciously used.

HMGB1 facilitates hypoxia-induced vWF upregulation through TLR2-MYD88-SP1 pathway

Increased plasma level of von Willebrand Factor (vWF) is associated with major cardiovascular diseases. We previously reported that multimeric vWF binds to NO synthase and inhibits insulin-induced production of NO, thus promoting insulin resistance during acute hypoxia (AH). However, the transcriptional regulation of vWF during AH is not clearly understood. Here, we investigated the mechanisms underlying the upregulation of vwf in mice. AH significantly upregulates the tlr2, tlr3, myd88, and vwf expression and phosphorylation of specificity protein 1 (SP1). Furthermore, AH significantly upregulates high mobility group box-1 (HMGB1) in a time-dependent manner. Moreover, a TLR2 agonist upregulates vWF but a TLR3 agonist does not. Pretreatment with an HMGB1 inhibitor, TLR2-immunoneutralizing antibody, or SP1 inhibitor significantly inhibits vWF expression. Furthermore, Tlr2 silencing completely inhibited MYD88, vWF expression, and SP1 phosphorylation. However, pretreatment with glycyrrhizic acid or silencing of Tlr2 completely blocks binding of Sp1 to the Vwf promoter, thus inhibiting its expression, and enhances insulin resistance during AH. Patients with type 2 diabetes mellitus also showed significantly elevated levels of HMGB1, TLR2, SP1, and vWF, thereby supporting the results of the murine model of AH. Taken together, HMGB1 upregulates vWF in vivo through the TLR2-MYD88-SP1 pathway in mice.

Biofilm Formation and Motility Depend on the Nature of the Acinetobacter baumannii Clinical Isolates

Acinetobacter baumannii is a nosocomial pathogen involved in various infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteremia. The severity and the type of infections depend on the genetic and phenotypic variations of the strains. In this study, we compared the extent of biofilm formation and motility displayed by 60 multidrug-resistant A. baumannii clinical strains isolated from blood and sputum samples from patients from Southern India. Our results showed that isolates from the sputum samples formed significantly more robust biofilm compared to the blood isolates. On the other hand, we observed that the blood isolates were more motile than the sputum isolates. To the best of our knowledge, this is the first study that systematically evaluated the correlation between these two phenotypic traits and the nature of the isolates.

Crystal structure of histone-like protein from Streptococcus mutans refined to 1.9 Å resolution

Nucleoid-associated proteins (NAPs) in prokaryotes play an important architectural role in DNA bending, supercoiling and DNA compaction. In addition to architectural roles, some NAPs also play regulatory roles in DNA replication and repair, and act as global transcriptional regulators in many bacteria. Bacteria encode multiple NAPs and some of them are even essential for survival. Streptococcus mutans, a dental pathogen, encodes one such essential NAP called histone-like protein (HLP). Here, the three-dimensional structure of S. mutans HLP has been determined to 1.9 Å resolution. The HLP structure is a dimer and shares a high degree of similarity with other bacterial NAPs, including HU. Since HLPs are essential for the survival of pathogenic streptococci, this structure determination is potentially beneficial for future drug development against these pathogens.

A Multicenter Evaluation of a Closed-Loop Anesthesia Delivery System: A Randomized Controlled Trial

BACKGROUND

Closed-loop systems for anesthesia delivery have been shown to outperform traditional manual control in different clinical settings. The present trial was aimed at evaluating the feasibility and efficacy of Bispectral Index (BIS)-guided closed-loop anesthesia delivery system (CLADS) in comparison with manual control across multiple centers in India.

METHODS

Adult patients scheduled for major surgical procedures of an expected duration of 1 to 3 hours were randomized across 6 sites into 2 groups: a CLADS group and a manual group. In the manual control group, propofol infusion was titrated manually by the attending anesthesiologist to a BIS of 50 during induction and maintenance. Analgesia was maintained with fentanyl infusion and nitrous oxide in both groups. In the CLADS group, both induction and maintenance of anesthesia were performed automatically using CLADS. The primary outcome measure was the performance of the system as assessed by the percentage of total anesthesia time BIS remained ±10 of target BIS. The secondary outcome measures were a percentage of anesthesia-time heart rate and mean arterial pressure within 25% of the baseline, median absolute performance error, wobble, and global score. Wobble indicates intraindividual variability in the control of BIS, and global score reflects the overall performance; lower values indicate superior performance for both parameters. The performance parameters of the system also were compared among the participating sites.

RESULTS

Two hundred forty-two patients were randomized. BIS was maintained within ±10 of target for significantly longer time in the CLADS group (81.4% ± 8.9 % of anesthesia duration) than in the manual group (55.34% ± 25%, P < 0.0001). The indices that assess performance were significantly better in the CLADS group than the manual group as follows: median absolute performance error was 10 (10, 12) (median [interquartile range]) in the CLADS group versus 18 (14, 24) in the manual group, P < 0.0001; wobble was 9 (8, 10) in CLADS group versus 10 (8, 14) in the manual group, P = 0.0009; and Global score, which reflects overall performance, was 24 (19, 30) in the CLADS group versus 51 (31, 99) in the manual group, P < 0.0001. The percentage of time heart rate was within 25% of the baseline was significantly greater in the CLADS group (heart rate of 95 [87, 99], median [interquartile range], in the CLADS group versus 90 [75, 98] in the manual group P = 0.0031). On comparison of data between the centers, the performance parameters did not differ significantly among the centers in the CLADS group (P = 0.94), but the parameters differed significantly among the centers in the manual group (P < 0.001).

CONCLUSIONS

Our study in a multicenter setting proves the consistently better performance of automated anesthesia drug delivery compared with conventional manual control. This highlights an important advantage of an automated system for delivering standardized anesthesia, thereby overcoming differences in practices among anesthesiologists.

Extracellular RNA facilitates hypoxia-induced leukocyte adhesion and infiltration in the lung through TLR3-IFN-γ-STAT1 signaling pathway

Endogenous ligands released from dying cells, including extracellular RNA (eRNA), cause TLR activation, which is associated with inflammation and vascular diseases. However, the importance of this response in acute hypoxia (AH) remains unexplored. Here, we observed eRNA-mediated TLR3 activation during exposure of mice to AH in the absence of exogenous viral stimuli. RNaseA treatment diminished AH-induced expression of IFN and cell adhesion molecules (CAMs) and myeloid cell infiltration in the lung, and TLR3 gene silencing or neutralization with antibodies markedly attenuated AH- or poly I:C-induced IFN and CAM expression and leukocyte adhesion (LA) and myeloid cell infiltration in the lung. However, RNaseA treatment or TLR3 gene silencing failed to alter AH-induced cell death and proliferation in lung vasculature. Furthermore, IFN-γ--but not IFN-α--regulated AH-induced CAM expression and LA. Treatment with RNaseA, TLR3 siRNA, neutralizing antibodies, or a STAT1 inhibitor substantially decreased AH- and poly I:C-induced STAT1 phosphorylation, CAM expression, and myeloid cell infiltration, suggesting a central role for STAT1 phosphorylation in AH-induced LA and infiltration. We conclude that eRNA activates TLR3 and facilitates, through in vivo IFN-γ-STAT1 signaling, AH-induced leukocyte infiltration in the lung. Thus, RNaseA might provide a therapeutic alternative for patients with lung diseases.

Gene Regulation by the LiaSR Two-Component System in Streptococcus mutans

The LiaSR two-component signal transduction system regulates cellular responses to several environmental stresses, including those that induce cell envelope damages. Downstream regulons of the LiaSR system have been implicated in tolerance to acid, antibiotics and detergents. In the dental pathogen Streptococcus mutans, the LiaSR system is necessary for tolerance against acid, antibiotics, and cell wall damaging stresses during growth in the oral cavity. To understand the molecular mechanisms by which LiaSR regulates gene expression, we created a mutant LiaR in which the conserved aspartic acid residue (the phosphorylation site), was changed to alanine residue (D58A). As expected, the LiaR-D58A variant was unable to acquire the phosphate group and bind to target promoters. We also noted that the predicted LiaR-binding motif upstream of the lia operon does not appear to be well conserved. Consistent with this observation, we found that LiaR was unable to bind to the promoter region of lia; however, we showed that LiaR was able to bind to the promoters of SMU.753, SMU.2084 and SMU.1727. Based on sequence analysis and DNA binding studies we proposed a new 25-bp conserved motif essential for LiaR binding. Introducing alterations at fully conserved positions in the 25-bp motif affected LiaR binding, and the binding was dependent on the combination of positions that were altered. By scanning the S. mutans genome for the occurrence of the newly defined LiaR binding motif, we identified the promoter of hrcA (encoding a key regulator of the heat shock response) that contains a LiaR binding motif, and we showed that hrcA is negatively regulated by the LiaSR system. Taken together our results suggest a putative role of the LiaSR system in heat shock responses of S. mutans.

Genetic tools for manipulating Acinetobacter baumannii genome: an overview

Acinetobacter baumannii is an emerging nosocomial pathogen involved in a variety of infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteraemia. A. baumannii has become resistant to most of the commonly used antibiotics and multidrug-resistant isolates are becoming a severe problem in the healthcare setting. In the past few years, whole-genome sequences of >200 A. baumannii isolates have been generated. Several methods and molecular tools have been used for genetic manipulation of various Acinetobacter spp. Here, we review recent developments of various genetic tools used for modification of the A. baumannii genome, including various ways to inactivate gene function, chromosomal integration and transposon mutagenesis.

Degradation of SsrA-tagged proteins in streptococci

In prokaryotes, a conserved small RNA molecule, called tmRNA, rescues ribosomes from proteins that are abnormally truncated due to the presence of rare codons or degraded mRNA. During the rescue process, a peptide tag (SsrA) encoded by tmRNA is cotranslationally added to the truncated polypeptides, thereby targeting these proteins for proteolytic degradation. In Escherichia coli, ClpXP and ClpAP proteases primarily degrade SsrA-tagged proteins. Other proteases such as Lon and FtsH also participate in the degradation in E. coli. However, in Bacillus subtilis, ClpXP is the major protease that degrades the SsrA-tagged proteins. Degradation of SsrA-tagged protein in streptococci is not well understood except that ClpXP is responsible for the majority of the degradation. Here we show that in Streptococcus mutans, in addition to ClpXP, two other Clp complexes, ClpCP and ClpEP, are also involved in the degradation. We also found that ClpCP- and ClpEP-mediated proteolysis of SsrA-tagged substrates is induced by heat stress. As ClpCP and ClpEP proteins are highly conserved in streptococci, we predicted that ClpEP- and ClpCP-mediated degradation of SsrA-tagged proteins might be operational in other streptococci.

Identification of the amino acids essential for LytSR-mediated signal transduction in Staphylococcus aureus and their roles in biofilm-specific gene expression

Recent studies have demonstrated that expression of the Staphylococcus aureus lrgAB operon is specifically localized within tower structures during biofilm development. To gain a better understanding of the mechanisms underlying this spatial control of lrgAB expression, we carried out a detailed analysis of the LytSR two-component system. Specifically, a conserved aspartic acid (Asp53) of the LytR response regulator was shown to be the target of phosphorylation, which resulted in enhanced binding to the lrgAB promoter and activation of transcription. In addition, we identified His390 of the LytS histidine kinase as the site of autophosphorylation and Asn394 as a critical amino acid involved in phosphatase activity. Interestingly, LytS-independent activation of LytR was observed during planktonic growth, with acetyl phosphate acting as a phosphodonor to LytR. In contrast, mutations disrupting the function of LytS prevented tower-specific lrgAB expression, providing insight into the physiologic environment within these structures. In addition, overactivation of LytR led to increased lrgAB promoter activity during planktonic and biofilm growth and a change in biofilm morphology. Overall, the results of this study are the first to define the LytSR signal transduction pathway, as well as determine the metabolic context within biofilm tower structures that triggers these signaling events.

Evaluation of closed-loop anesthesia delivery for propofol anesthesia in pediatric cardiac surgery

OBJECTIVE

The objective of this study was to compare the feasibility of closed-loop anesthesia delivery with manual control of propofol in pediatric patients during cardiac surgery.

METHODS

Forty ASA II-III children, undergoing elective cardiac surgery under cardiopulmonary bypass (CPB) in a tertiary care hospital, were randomized to receive propofol either through a closed-loop anesthesia delivery system (CL group) or through traditional manual control (manual group) to achieve a target BIS of 50. Patients were induced and subsequently maintained with a propofol infusion. The propofol usage and the efficacy of closed-loop system in controlling BIS within ±10 of the target were compared with that of manual control.

RESULTS

The maintenance of BIS within ±10 of target and intraoperative hemodynamic stability were similar between the two groups. However, induction dose of propofol was less in the CL group (2.06 ± 0.79 mg·kg(-1) ) than the manual group (2.95 ± 1.03 mg·kg(-1) ) (P = 0.006) with less overshoot of BIS during induction in the closed-loop group (P = 0.007). Total propofol used in the off-CPB period was less in the CL group (6.29 ± 2.48 mg·kg(-1) h(-1) vs 7.82 ± 2.1 mg·kg(-1) h(-1) ) (P = 0.037). Phenylephrine use in the pre-CPB period was more in the manual group (16.92 ± 10.92 μg·kg(-1) vs 5.79 ± 5.98 μg·kg(-1) ) (P = 0.014). Manual group required a median of 18 (range 8-29) dose adjustments per hour, while the CL group required none.

CONCLUSION

This study demonstrated the feasibility of closed-loop controlled propofol anesthesia in children, even in challenging procedures such as cardiac surgery. Closed-loop system needs further and larger evaluation to establish its safety and efficacy.

A six-month prospective study to find out the treatment outcome, prognosis and offending drugs in toxic epidermal necrolysis from an urban institution in kolkata

Toxic epidermal necrolysis is the life-threatening dermatological emergency, most often an adverse cutaneous drug reaction with high mortality. A 6-month prospective study was conducted in our institution to find out the offending drugs, to assess the prognosis on admission using SCORTEN: Severity of illness score and to find out the treatment outcome. Anticonvulsants, NSAIDs and sulphonamides are the common offending agents; but in our study, 2 were due to homeopathic medicines. Out of 20 patients, on the date of admission SCORTEN prognostic score was 2 in 11 patients, 3 in 8 patients and 4 in 1 patient. Eighteen patients were treated with dexamethasone intramuscular injection and 2 patients got intravenous immunoglobulin (IVIG). All patients survived without any mortality. Though improvement was slightly faster with IVIG, early administration of corticosteroids was also of encouraging efficacy and should be considered in developing countries due to low cost. No mortality in our study suggests need to validate the SCORTEN index in our country in a large number of patients.

Surgical outcome of laparoscopic and open surgery of pediatric inguinal hernia

Inguinal hernia repair is one of the most frequently performed surgical procedures in infants and young children. This prospective comparative study was conducted with initial experience in the department of pediatric surgery, Dhaka Shishu (children) hospital during the period of July 2007 to August 2008. We enrolled 62 children undergoing surgery for inguinal hernia, of which 30 underwent laparoscopic procedure (bilateral in 21, unilateral 9) and 32 open procedures (bilateral in 5, unilateral in 27). Mean±SD patient age was 5.92±2.11 months in laparoscopic group and 6.63±2.64 months in open group (p=0.264), 3 months to 5 years in both groups. Patients were studied under variables of operative time, duration of postoperative hospital stay & post operative complications. During laparoscopy a contralateral patent processus vaginalis of ≥2cm was noted and repaired peroperatively in 18 out of 27 children (66%), who were initially diagnosed as unilateral hernia. For unilateral repair mean±SD operative time was significantly longer in Group A (62.63±52.75) minutes compares to the Group B (29.37±9.40), p<0.001. On the contrary, for bilateral repair Mean±SD operative time was comparable between the two groups (64.65±49.70) minutes for laparoscopy & (35.65±11.53 minutes) for open herniotomy & P=0.01, that was not remarkably significant. The mean±SD post operative length of hospital stay (in hours) 36.00±32.7 hours in Group A compared to 29.97±11.82 hours in Group B which was not statically significant (p=0.342). The mean±SD follow up was 24.5±10.5 months in laparoscopic group (Group A) & 22.5±10.5 months in open group (Group B), p=0.251. Regarding post operative complication, in this study, contra lateral metachronous inguinal hernia (CMIH) manifested in none of the patient out of 27 (total unilateral repaired number) patients in laparoscopic group but contrary to this in open group 2 patients out of 27 had developed CMIH & p value was <0.05, which is statistically significant. There were 2 cases of scrotal hydrocele out of 30, observed in Group A whereas 1 case out of 32 in Group B, p=0.49, which was statistically insignificant. The scrotal hydrocele was lasted only for 2 days & resolved spontaneously. About recurrence after operation, our study noted that, 1 case (3.3%) out of 30 in laparoscopic group and 2 cases (6%) out of 32 in open surgery group had developed recurrent inguinal hernia in about one year follow up where p value was 0.459, & it was statistically insignificant. In this study, none of the patient had developed post operative testicular atrophy (due to any vas or vascular injury) or testicular ascend. So, overall this study result implies that, Laparoscopic herniotomy might be a safe and effective option as open herniotomy for the treatment of inguinal hernia in children but which one would be superior or best option it requires a large series of randomized trial.

Studies on comparison of the efficacy of terbinafine 1% cream and butenafine 1% cream for the treatment of Tinea cruris

BACKGROUND

In this study, 76 male patients aged between 18 and 61 years affected with Tinea cruris attending the outpatient department of NRS Medical College during a 1-year period were selected.

MATERIALS AND METHODS

The patients were divided into two groups as Regimen I (n 37) and Regimen II (n 39) who were treated with Terbinafine (gr I) cream and Butenafine (gr II) cream, respectively.

RESULTS

The predominant pathogen was found to be Trichophyton rubrum in 99% of cases. Mycological cure, overall cure and effective treatment were evaluated on 7, 14 and 42 days.

CONCLUSIONS

From the study, it was found that Butenafine produced the quickest result and primary efficacy end points were much higher with Butenafine cream than that of Terbinafine cream and this difference was statistically significant (P < 0.01).

A key role of toll-like receptor 3 in tissue factor activation through extracellular signal regulated kinase 1/2 pathway in a murine hypoxia model

Hypoxemia in the circulation can lead to venous thrombosis (VT) through tissue factor (TF) activation, but the mechanism of TF activation in hypoxia remains obscure. Ligands released from damaged tissues or cells due to hypoxia are identified by various pattern-recognition receptors (PRR), including Toll-like receptor3 (TLR3). In the present study, we investigated the mechanism of TF activation during acute hypoxia in a rat model. The expression of TLR3 and TF was analyzed by immunoblotting and RT-PCR. The TF activity was evaluated by two-stage chromogenic assay and fibrin deposition was detected by immunohistochemistry. The expression of TLR3, TF, and TF activity was increased significantly 6 h post acute hypoxia and then decreased gradually. The contribution of TLR3 in TF activation was investigated by poly I:C and TLR3 neutralizing antibody. We also found increased ERK phosphorylation both in acute hypoxia and poly I:C treatment. We further showed that the pre-treatment of TLR3 neutralizing antibody or ERK inhibitor (PD98059) 2 h prior to acute hypoxia or poly I:C treatment completely abrogated ERK phosphorylation and TF activation. The pre-treatment of TLR3 neutralizing antibody also inhibited fibrin deposition in lung vasculature. These data indicate that acute hypoxia induced TF activation is mediated through TLR3-ERK1/2 pathway.

A comparative study of efficacy and safety of arformoterol and salbutamol nebulization as rescue therapy in acute non-severe asthma

Arformoterol, a long-acting beta-2 agonist, has a rapid onset and long duration of action. Its role as rescue medication in acute asthma attack is undetermined. To compare the efficacy and tolerability of arformoterol with salbutamol nebulization, a study was conducted among 50 patients with acute non-severe asthma. Patients were randomly assigned to group 1 (n = 25) and group 2 (n = 25) who received three doses of salbutamol and arformoterol nebulization, respectively, at 20-min intervals. The peak expiratory flow rate (PEFR) was measured at the baseline and 5 min after each dose. The demographics and baseline characteristics were comparable between the two groups. The mean PEFR significantly increased in both these groups when compared with the baseline. The increases in the PEFR in two groups were similar after the third dose. The adverse effects in both these groups were minor. Arformoterol was as effective and safe as salbutamol in acute non-severe asthma.

A study on central corneal thickness and optic disc size in patients with primary open angle glaucoma

The aim of the study was to evaluate a possible relationship between central corneal thickness (CCT) and optic disc area in patients with primary open angle glaucoma (POAG). Patients with POAG and age matched control group underwent routine ocular examination along with optic nerve head evaluation by Stratus optical coherence tomography (OCT) and CCT measurement by ultrasound pachymetry. Pearson's coefficient was calculated in both groups to find out correlation between these two parameters. In this series 90 eyes of 45 control subjects and 94 eyes of 47 POAG patients were studied. In the control group 40% were female, 60% male and among the POAG patients 34% female, 66% male. Mean CCT in control subjects was 566.98 micron (SD = 19.36, n = 90) and in POAG patients was 526.61 micron (SD = 29.93, n = 94). There was a significant difference in two groups (p = 0.0002). Disc area in control group had mean of 2.32mm(2) (SD = 0.305, n = 90) and in POAG group 2.982mm(2) (SD = 0.566, n = 94). Statistically significant difference was found among the two groups (p = 0.0). CCT was inversely correlated with optic disc size. In control subjects, r = -0.141, but it was not statistically significant (p = 0.092). In POAG group, r = -0.256 and the correlation was statistically significant (p = 0.0063). CCT was significantly less in POAG patients compared to control subjects. Mean disc area was significantly higher among the POAG group compared to control subjects. CCT was inversely correlated with disc area in both groups, but was statistically significant in POAG patients.

CovR-controlled global regulation of gene expression in Streptococcus mutans

CovR/S is a two-component signal transduction system (TCS) that controls the expression of various virulence related genes in many streptococci. However, in the dental pathogen Streptococcus mutans, the response regulator CovR appears to be an orphan since the cognate sensor kinase CovS is absent. In this study, we explored the global transcriptional regulation by CovR in S. mutans. Comparison of the transcriptome profiles of the wild-type strain UA159 with its isogenic covR deleted strain IBS10 indicated that at least 128 genes (∼6.5% of the genome) were differentially regulated. Among these genes, 69 were down regulated, while 59 were up regulated in the IBS10 strain. The S. mutans CovR regulon included competence genes, virulence related genes, and genes encoded within two genomic islands (GI). Genes encoded by the GI TnSmu2 were found to be dramatically reduced in IBS10, while genes encoded by the GI TnSmu1 were up regulated in the mutant. The microarray data were further confirmed by real-time RT-PCR analyses. Furthermore, direct regulation of some of the differentially expressed genes was demonstrated by electrophoretic mobility shift assays using purified CovR protein. A proteomic study was also carried out that showed a general perturbation of protein expression in the mutant strain. Our results indicate that CovR truly plays a significant role in the regulation of several virulence related traits in this pathogenic streptococcus.

[A method for differential identification of group C and G streptococci with PCR]

The paper describes a rapid method for PCR identification of Groups C and G streptococci (Streptococcus dysgalactiae subspecies equisimilis, Streptococcus constellatus, and Streptococcus anginosus) that cause human disease. Species-specific regions of the cpn60 gene encoding heat shock protein GroEL (HSP60) were chosen as markers for PCR diagnosis; three pairs of primers were constructed for these regions, each of which was peculiar to the specific type. The method was tested on a large collection of pathogenic streptococci of different serogroups isolated from man and animals; its specificity was shown to identify S. dysgalactiae subsp. equisimilis, S. constellatus, and S. anginosus. The proposed method has all benefits of PCR-based techniques, which enables it to be used for the purposes of molecular epidemiology.

Dual role of nanoparticles as drug carrier and drug

The conventional chemotherapeutic agents used in the treatment of human malignancies are directed nonspecifically against both malignant and nonmalignant cells, often limiting their efficacy with having serious side effects. Recent development of drug delivery vehicles has opened up the possibility of targeted drug delivery systems with the potential of achieving maximum efficacy with minimal toxicity. The possibility of using a nanomaterial as a combinational drug component is intuitively evident as it would compensate the toxicity level by enhancing drug delivery efficiency. Additionally, cell-specific cytotoxicity (reported earlier by our group) of the nanovehicle itself may potentiate a more effective targeted cell killing. In this paper, we explore the possibility of using gold nanoparticles playing the dual role of an anticancer agent and a carrier of a chemotherapeutic drug. This is demonstrated using vincristine sulfate (VS), salt of an alkaloid often used in the treatment of multiple myeloma (MM), and U266 as a test MM cell line. The drug VS shows the expected G2-M-phase arrest of cells. Notably, bare gold nanoparticle shows arrest of the S phase cells that may be particularly important in case of slow-growing malignancies like MM where most of the cells remain in G1 phase of the cell cycle. The VS conjugated gold retains the activity of both gold nanoparticle and VS leading to a synergistic rise of the apoptotic cell population.

Activation of the SMU.1882 transcription by CovR in Streptococcus mutans

In Streptococcus mutans, the global response regulator CovR plays an important role in biofilm formation, stress-tolerance response, and caries production. We have previously shown that CovR acts as a transcriptional repressor by binding to the upstream promoter regions of its target genes. Here, we report that in vivo, CovR activates the transcription of SMU.1882, which encodes a small peptide containing a double-glycine motif. We also show that SMU.1882 is transcriptionally linked to comA that encodes a putative ABC transporter protein. Several genes from man gene clusters that encode mannose phosphotranferase system flank SMU.1882 -comA genes. Genomic comparison with other streptococci indicates that SMU.1882 is uniquely present in S. mutans, while the man operon is conserved among all streptococci, suggesting that a genetic rearrangement might have taken place at this locus. With the use of a transcriptional reporter system and semi-quantitative RT-PCR, we demonstrated the transcriptional regulation of SMU.1882 by CovR. In vitro gel shift and DNase I foot-printing analyses with purified CovR suggest that CovR binds to a large region surrounding the -10 region of the P(1882). Using this information and comparing with other CovR regulated promoters, we have developed a putative consensus binding sequence for CovR. Although CovR binds to P(1882), in vitro experiments using purified S. mutans RpoD, E. coli RNA polymerase, and CovR did not activate transcription from this promoter. Thus, we speculate that in vivo, CovR may interfere with the binding of a repressor or requires a cofactor.

A self-deleting Cre-lox-ermAM cassette, Cheshire, for marker-less gene deletion in Streptococcus pneumoniae

Although targeted mutagenesis of Streptococcus pneumoniae is readily accomplished with the aid of natural genetic transformation and chimeric donor DNA constructs assembled in vitro, the drug resistance markers often employed for selection of recombinant products can themselves be undesirable by-products of the genetic manipulation. A new cassette carrying the erythromycin-resistance marker ermAM that can be used as a temporary marker for selection of desired recombinants is described. The cassette may subsequently be removed at will by virtue of an embedded fucose-regulated Cre recombinase gene and terminal lox66 and lox71 Cre recognition sites, with retention of 34bp from the cassette as an inert residual double-mutant lox72 site.

From interfaces to surfaces: soft x-ray spectromicroscopy investigations of diindenoperylene thin films on gold

We present the results of photoemission electron microscopy investigations on diindenoperylene (DIP) thin films deposited on polycrystalline gold, prepared in order to have a roughness much larger than the molecular size. Our investigations revealed the ability of the DIP molecule to form well-organized films, exhibiting a different molecular orientation with respect to the already known λ and σ phases. In locally thicker film regions, the energy of the films is minimized by a molecular arrangement that has an asymptotic tendency to the σ phase.

A phenotypic microarray analysis of a Streptococcus mutans liaS mutant

Streptococcus mutans, a biofilm-forming Gram-positive bacterium that resides in the human oral cavity, is considered to be the primary aetiological agent of human dental caries. A cell-envelope stress-sensing histidine kinase, LiaS, is considered to be important for expression of virulence factors such as glucan-binding protein C and mutacin production. In this study, a liaS mutant was subjected to phenotypic microarray (PM) analysis of about 2000 phenotypes, including utilization of various carbon, nitrogen, phosphate and sulfur sources; osmolytes; metabolic inhibitors; and susceptibility to toxic compounds, including several types of antibiotics. Compared to the parental strain UA159, the liaS mutant strain (IBS148) was more tolerant to various inhibitors that target protein synthesis, DNA synthesis and cell-wall biosynthesis. Some of the key findings of the PM analysis were confirmed in independent growth studies and by using antibiotic discs and E-test strips for susceptibility testing.

Chirality and drugs in clinical practice and its ethical aspect

Recently specific enantiomer of different chiral molecules are being launched in the market as drugs. Here the rationality of scopes and uses of these drugs in therapeutic medicine is discussed including the ethical aspect.

Shuttle expression plasmids for genetic studies in Streptococcus mutans

A set of shuttle plasmids containing four different constitutive promoters was generated to facilitate overexpression of foreign and native genes in streptococci, such as Streptococcus mutans. The four promoters that were chosen were: P(ami), P(spac), P(23) and P(veg). These promoters are active in many Gram-positive bacteria, and allow various levels of gene expression depending on the host bacterium. Shuttle plasmids were constructed based on two types of broad-host-range replication origins: a rolling-circle replicon (pSH71) and a theta replicon (pAMbeta1). Shuttle plasmids derived from the pAMbeta1 replicon were generated to avoid the structural and segregational stability problems associated with rolling-circle replication, since these problems may be encountered during large gene cloning. In a complementation assay, we used one such plasmid to express a gene in trans to show the utility of these plasmids. In addition, a series of plasmids was generated for the expression of recombinant proteins with an N-terminal 6xHis tag or a C-terminal Strep-tag fusion, and, using a gene derived from S. mutans, we showed a high level of recombinant protein expression in S. mutans and Streptococcus pyogenes. Since these plasmids contain broad-host-range replication origins, and because the selected promoters are functional in many bacteria, they can be used for gene expression studies, such as complementation and recombinant protein expression.

Unmarked gene modification in Streptococcus mutans by a cotransformation strategy with a thermosensitive plasmid

Unmarked gene modifications are desirable for various genetic analyses; however, they have been difficult to construct without selectable markers. We describe here a new genetic method for constructing unmarked mutants in Streptococcus mutans. The desired mutant allele is first constructed and introduced into the strain by cotransformation with pGhost4, a thermosensitive plasmid that replicates in several low G+C Gram positive bacteria. With this method, we have modified two different loci with high frequency by insertion or deletion in S. mutans. Because pGhost4 contains a broad host range thermosensitive replicon, this method can be applied to any transformable low G+C Gram positive bacteria, including oral streptococci.

Regulation of gbpC expression in Streptococcus mutans

Streptococcus mutans, the principal causative agent of dental caries, produces four glucan-binding proteins (Gbp) that play major roles in bacterial adherence and pathogenesis. One of these proteins, GbpC, is an important cell surface protein involved in biofilm formation. GbpC is also important for cariogenesis, bacteremia, and infective endocarditis. In this study, we examined the regulation of gbpC expression in S. mutans strain UA159. We found that gbpC expression attains the maximum level at mid-exponential growth phase, and the half-life of the transcript is less than 2 min. Expression from PgbpC was measured using a PgbpC-gusA transcriptional fusion reporter and was analyzed under various stress conditions, including thermal, osmotic, and acid stresses. Expression of gbpC is induced under conditions of thermal stress but is repressed during growth at low pH, whereas osmotic stress had no effect on expression from PgbpC. The results from the expression analyses were further confirmed using semiquantitative reverse transcription-PCR analysis. Our results also reveal that CovR, a global response regulator in many Streptococcus spp., represses gbpC expression at the transcriptional level. We demonstrated that purified CovR protein binds directly to the promoter region of PgbpC to repress gbpC expression. Using a DNase I protection assay, we showed that CovR binds to DNA sequences surrounding PgbpC from bases -68 to 28 (where base 1 is the start of transcription). In summary, our results indicate that various stress conditions modulate the expression of gbpC and that CovR negatively regulates the expression of the gbpC gene by directly binding to the promoter region.

Regulation of the glucosyltransferase (gtfBC) operon by CovR in Streptococcus mutans

Streptococcus mutans is an important etiological agent of dental caries in humans. The extracellular polysaccharides synthesized by cell-associated glucosyltransferases (encoded by gtfBC) from sucrose have been recognized as one of the important virulence factors that promote cell aggregation and adherence to teeth, leading to dental plaque formation. In this study, we have characterized the effect of CovR, a global response regulator, on glucosyltransferase expression. Inactivation of covR in strain UA159 resulted in a marked increase in the GtfB and GtfC proteins, as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. With the use of a transcriptional reporter system of a single chromosomal copy of the PgtfB-gusA and PgtfC-gusA fusions, we confirmed the transcriptional regulation of these promoters by CovR. By in vitro electrophoretic mobility shift assays with purified CovR protein, we showed that CovR regulates these promoters directly. DNase I footprinting analyses suggest that CovR binds to large regions on these promoters near the transcription start sites. Taken together, our results indicate that CovR negatively regulates the expression of the gtfB and gtfC genes by directly binding to the promoter region.

Role of HtrA in surface protein expression and biofilm formation by Streptococcus mutans

The HtrA surface protease in gram-positive bacteria is involved in the processing and maturation of extracellular proteins and degradation of abnormal or misfolded proteins. Inactivation of htrA has been shown to affect the tolerance to thermal and environmental stress and to reduce virulence. We found that inactivation of Streptococcus mutans htrA by gene-replacement also resulted in a reduced ability to withstand exposure to low and high temperatures, low pH, and oxidative and DNA damaging agents. The htrA mutation affected surface expression of several extracellular proteins including glucan-binding protein B (GbpB), glucosyltransferases, and fructosyltransferase. In addition, htrA mutation also altered the surface expression of enolase and glyceraldehyde-3-phosphate dehydrogenease, two glycolytic enzymes that are known to be present on the streptococcal cell surface. As expected, microscopic analysis of in vitro grown biofilm structure revealed that the htrA deficient biofilms adopted a much more granular patchy appearance, rather than the relatively smooth confluent layer normally seen in the wild type. These results suggest that HtrA plays an important role in the biogenesis of extracellular proteins including surface associated glycolytic enzymes and in biofilm formation of S. mutans.

Tetra-t-butyl magnesium phthalocyanine on gold: Electronic structure and molecular orientation

In this work we have investigated the electronic structure and the molecular orientation of (t-Bu)(4)PcMg (tetra-t-butyl magnesium phthalocyanine) on polycrystalline and single crystalline gold substrates using photoemission spectroscopy and x-ray absorption spectroscopy, and we compare the results to the unsubstituted PcCu (copper phthalocyanine). The C 1s photoemission spectrum is described similar to unsubstituted relatives with an additional component for the aliphatic substituents. The variation of the excitation energy causes distinct differences in the shape of the C 1s spectrum, which is very useful for the analysis of the molecular orientation in the uppermost layer. It is shown that despite of the sterically demanding substituents, ordered sublimed films of (t-Bu)(4)PcMg are accessible, the orientation of the molecules, however, is different from the orientation of the unsubstituted relatives.

Identification of rocA, a positive regulator of covR expression in the group A streptococcus

In the group A streptococcus (GAS; Streptococcus pyogenes), a two-component system known as CovRS (or CsrRS) regulates about 15% of the genes, including several important virulence factors like the hyaluronic acid capsule. Most of these genes, including covR itself, are negatively regulated by CovR. We have isolated two independent ISS1 insertions in an open reading frame (ORF) that increases CovR expression as measured by a Pcov-gusA reporter fusion in single copy in the GAS chromosome. This ORF, named rocA for "regulator of Cov," activates covR transcription about threefold. As expected, a rocA mutant is mucoid and produces more transcript from the has promoter since this promoter is repressed by CovR. This effect is dependent on the presence of a wild-type covR gene. In contrast to its activation of Pcov, RocA negatively regulates its own expression. This autoregulation is not dependent on the presence of the covR gene. All the phenotypes of the rocA mutant were complemented by the presence of the rocA gene on a plasmid. The rocA gene is present in strains of all nine M serotypes of GAS tested and is absent from strains representing 11 other groups of streptococci and related bacteria, including strains of the closely related group C and G streptococci. It seems likely that rocA plays an important role in the pathogenesis of GAS since it affects expression of the global regulator CovR.

MutS2 family protein from Pyrococcus furiosus

MutS2 protein of Pyrococcus furiosus has been cloned and over-expressed. Initial characterization reveals that PfuMutS2 possesses a thermostable ATPase activity and a thermostable, nonspecific DNA binding activity. However, PfuMutS2 does not have any detectable mismatch-specific DNA binding activity. It is the first in vitro characterization of an MutS2 family protein.

Generation and surface localization of intact M protein in Streptococcus pyogenes are dependent on sagA

The M protein is an important surface-located virulence factor of Streptococcus pyogenes, the group A streptococcus (GAS). Expression of M protein is primarily controlled by Mga, a transcriptional activator protein. A recent report suggested that the sag locus, which includes nine genes necessary and sufficient for production of streptolysin S, another GAS virulence factor, is also needed for transcription of emm, encoding the M protein (Z. Li, D. D. Sledjeski, B. Kreikemeyer, A. Podbielski, and M. D. Boyle, J. Bacteriol. 181:6019-6027, 1999). To investigate this in more detail, we constructed an insertion-deletion mutation in sagA, the first gene in the sag locus, in the M6 strain JRS4. The resulting strain, JRS470, produced no detectable streptolysin S and showed a drastic reduction in cell surface-associated M protein, as measured by cell aggregation and Western blot analysis. However, transcription of the emm gene was unaffected by the sagA mutation. Detailed analysis with monoclonal antibodies and an antipeptide antibody showed that the M protein in the sagA mutant strain was truncated so that it lacks the C-repeat region and the C-terminal domain required for anchoring it to the cell surface. This truncated M protein was largely found, as expected, in the culture supernatant. Lack of surface-located M protein made the sagA mutant strain susceptible to phagocytosis. Thus, although sagA does not affect transcription of the M6 protein gene, it is needed for the surface localization of this important virulence factor.

In vivo evidence for two active nuclease motifs in the double-strand break repair enzyme RexAB of Lactococcus lactis

In bacteria, double-strand DNA break (DSB) repair involves an exonuclease/helicase (exo/hel) and a short regulatory DNA sequence (Chi) that attenuates exonuclease activity and stimulates DNA repair. Despite their key role in cell survival, these DSB repair components show surprisingly little conservation. The best-studied exo/hel, RecBCD of Escherichia coli, is composed of three subunits. In contrast, RexAB of Lactococcus lactis and exo/hel enzymes of other low-guanine-plus-cytosine branch gram-positive bacteria contain two subunits. We report that RexAB functions via a novel mechanism compared to that of the RecBCD model. Two potential nuclease motifs are present in RexAB compared with a single nuclease in RecBCD. Site-specific mutagenesis of the RexA nuclease motif abolished all nuclease activity. In contrast, the RexB nuclease motif mutants displayed strongly reduced nuclease activity but maintained Chi recognition and had a Chi-stimulated hyperrecombination phenotype. The distinct phenotypes resulting from RexA or RexB nuclease inactivation lead us to suggest that each of the identified active nuclease sites in RexAB is involved in the degradation of one DNA strand. In RecBCD, the single RecB nuclease degrades both DNA strands and is presumably positioned by RecD. The presence of two nucleases would suggest that this RecD function is dispensable in RexAB.

Distinctive features of homologous recombination in an 'old' microorganism, Lactococcus lactis

Homologous recombination is needed to assure faithful inheritance of DNA material, especially under stress conditions. The same enzymes that repair broken chromosomes via recombination also generate biodiversity. Their activities may result in intrachromosomal rearrangements, assimilation of foreign DNA, or a combination of these events. It is generally supposed that homologous recombination systems are conserved, and function the same way everywhere as they do in Escherichia coli, the accepted paradigm. Studies in an 'older' microorganism, the gram-positive bacterium of the low GC branch Lactococcus lactis, confirm that many enzymes are conserved across species lines. However, the main components of the double strand break (DSB) repair system, an exonuclease/helicase (Exo/hel) and a short DNA modulator sequence Chi, differ markedly between bacteria, especially when compared to the gram-negative analogues. Based on our studies, a model is proposed for the functioning of the two-subunit Exo/hel of L. lactis and other gram-positive bacteria, which differs from that of the three-subunit E. coli enzyme. The differences between bacterial DSB repair systems may underlie a selection for diversity when dealing with DSB. These and other features of homologous recombination in L. lactis are discussed.

Disruption of the helix-u-turn-helix motif of MutS protein: loss of subunit dimerization, mismatch binding and ATP hydrolysis

The DNA mismatch repair protein, MutS, is a dimeric protein that recognizes mismatched bases and has an intrinsic ATPase activity. Here, a series of Taq MutS proteins having C-terminal truncations in the vicinity of a highly conserved helix-u-turn-helix (HuH) motif are assessed for subunit oligomerization, ATPase activity and DNA mismatch binding. Those proteins containing an intact HuH region are dimers; those without the HuH region are predominantly monomers in solution. Steady-state kinetics of truncated but dimeric MutS proteins reveals only modest decreases in their ATPase activity compared to full-length protein. In contrast, disruption of the HuH region results in a greatly attenuated ATPase activity. In addition, only dimeric MutS proteins are proficient for mismatch binding. Finally, an analysis of the mismatch repair competency of truncated Escherichia coli MutS proteins in a rifampicin mutator assay confirms that the HuH region is critical for in vivo function. These findings indicate that dimerization is critical for both the ATPase and DNA mismatch binding activities of MutS, and corroborate several key features of the MutS structure recently deduced from X-ray crystallographic studies.

Requirement for Phe36 for DNA binding and mismatch repair by Escherichia coli MutS protein

The MutS family of DNA repair proteins recognizes base pair mismatches and insertion/deletion mismatches and targets them for repair in a strand-specific manner. Photocrosslinking and mutational studies previously identified a highly conserved Phe residue at the N-terminus of Thermus aquaticus MutS protein that is critical for mismatch recognition in vitro. Here, a mutant Escherichia coli MutS protein harboring a substitution of Ala for the corresponding Phe36 residue is assessed for proficiency in mismatch repair in vivo and DNA binding and ATP hydrolysis in vitro. The F36A protein is unable to restore mismatch repair proficiency to a mutS strain as judged by mutation to rifampicin or reversion of a specific point mutation in lacZ. The F36A protein is also severely deficient for binding to heteroduplexes containing an unpaired thymidine or a G:T mismatch although its intrinsic ATPase activity and subunit oligomerization are very similar to that of the wild-type MutS protein. Thus, the F36A mutation appears to confer a defect specific for recognition of insertion/deletion and base pair mismatches.