Synthesis and antibacterial activity of N-(5-benzylthio-1,3,4-thiadiazol-2-yl) and N-(5-benzylsulfonyl-1,3,4-thiadiazol-2-yl)piperazinyl quinolone derivatives

A series of N-(5-benzylthio-1,3,4-thiadiazol-2-yl) and N-(5-benzylsulfonyl-1,3,4-thiadiazol-2-yl) derivatives of piperazinyl quinolones was synthesized and evaluated for antibacterial activity against Gram-positive and Gram-negative microorganisms. Some of these derivatives exhibit high activity against Gram-positive bacteria; Staphylococcus aureus and Staphylococcus epidermidis, comparable or more potent than their parent N-piperazinyl quinolones norfloxacin and ciprofloxacin as reference drugs. The SAR of this series indicates that both the structure of the benzyl unit and the S or SO(2) linker dramatically impact antibacterial activity.     

Clean or Dirty? A Systematic Review of Splash Basin Use and Its Infectious Potential in Orthopaedic Surgery

BackgroundSplash basins are used in orthopaedic surgery cases to wash and hold instrumentsintraoperatively. This systematic review aims to summarize information on contamination of splash basins intraoperatively.MethodsA systematic review was conducted using the following search terms: “splash basin” or “splash bucket.” Two authors independently reviewed the literature. Studies were included if they reported on intraoperative splash basin contamination rates. Studies were excluded if they were not relevant to orthopaedic surgery, non-English articles, or repeat studies yielded by different online databases.ResultsThere were seven studies included in this review. The median contamination rate of sterile water or physiologic saline splash basins was 23.9% [range: 2%-74%]. The addition of surgical antiseptics to sterile water splash basins was associated with 0% contamination rates in two studies. The most frequent splash basin contaminants identified in bacterial culture were coagulase negative staphylococcus (50%) and staphylococcus aureus (10%).ConclusionThe splash basin appears to be a frequent source of contamination in the operating room. Many studies suggest abandoning splash basin use altogether, although the efficacy of alternative methods such as cleaning instruments with lap pads in avoiding contamination of the sterile field has not been studied. Further investigation into surgical teams’ use of the splash basin and the contents of the splash basin as they relate to contamination rates may help advance our understanding of optimal use of this surgical tool. Shorter case durations and dilute surgical antiseptics in splash basins appear associated with lower splash basin contamination risk. Level of Evidence: V     

Length–weight relationships of three fish species from a tropical mangrove estuary of Sarawak,Malaysia

Length–weight relationships for three mangrove fish species, Setipinna melanochir (Bleeker, 1849), Ilisha elongata (Anonymous [Bennett], 1830), and Nibea soldado (Lacépède, 1802) were determined. Samplings were conducted in a tropical mangrove estuary, Sarawak, Malaysia (3°59′25.76′′N; 113°43′51.6′′E) at the peak of three different seasons using gillnets (100 × 2.5 m, mesh sizes 1, 2 and 4 inches) during 2014–2015. No information regarding length–weight relationships of these species was reported previously in FishBase.     

A new location to split Cre recombinase for protein fragment complementation

We have previously described a recombinase‐mediated gene stacking system in which the Cre recombinase is used to remove lox‐site flanked DNA no longer needed after each round of Bxb1 integrase‐mediated site‐specific integration. The Cre recombinase can be conveniently introduced by hybridization with a cre‐expressing plant. However, maintaining an efficient cre‐expressing line over many generations can be a problem, as high production of this DNA‐binding protein might interfere with normal chromosome activities. To counter this selection against high Cre activity, we considered a split‐cre approach, in which Cre activity is reconstituted after separate parts of Cre are brought into the same genome by hybridization. To insure that the recombinase‐mediated gene stacking system retains its freedom to operate, we tested for new locations to split Cre into complementing fragments. In this study, we describe testing four new locations for splitting the Cre recombinase for protein fragment complementation and show that the two fragments of Cre split between Lys244 and Asn245 can reconstitute activity that is comparable to that of wild‐type Cre.     

The relationship between serum zinc levels and rheumatoid arthritis activity

Objective

Rheumatoid arthritis (RA) is one of the most prevalent chronic autoimmune diseases; it typically involves the hands, wrists, ankles, and eventually all joints. Some studies have reported that zinc serum levels are lower in patients with RA than in healthy individuals.

Materials and Methods

Seventy-nine patients with RAwere selected. The patients were all less than 75 years old and were diagnosed by a rheumatologist. Serum zinc levels were measured using the flame photometry method with a blood sample of 5 mL. The relationship between the average serum zinc level and disease activity was analyzed based on the DAS28 scoring scale for different RA groups. The significance threshold was set at p<0.05. Data analyses were implemented in SPSS 22.0.

Results

There was a significant inverse relationship between the serum zinc levels and disease activity. Chi-square tests were used to compare zinc serum levels with respect to disease activity. There were significant differences in zinc levels among three groups of patients with different levels of disease severity, such that disease activity increased as the serum zinc level decreased (p<0.001).

Conclusion

There was a significant inverse relationship between the serum zinc level and RA activity based on the DAS28 score. Therefore, it is recommended that mineral deficiencies should be addressed by optimizing the zinc supply along with other standard medications in order to reduce RA activity.

     

Quantitative imaging of alveolar recruitment with hyperpolarized gas MRI during mechanical ventilation

The aim of this study was to assess the utility of (3)He MRI to noninvasively probe the effects of positive end-expiratory pressure (PEEP) maneuvers on alveolar recruitment and atelectasis buildup in mechanically ventilated animals. Sprague-Dawley rats (n = 13) were anesthetized, intubated, and ventilated in the supine position ((4)He-to-O(2) ratio: 4:1; tidal volume: 10 ml/kg, 60 breaths/min, and inspiration-to-expiration ratio: 1:2). Recruitment maneuvers consisted of either a stepwise increase of PEEP to 9 cmH(2)O and back to zero end-expiratory pressure or alternating between these two PEEP levels. Diffusion MRI was performed to image (3)He apparent diffusion coefficient (ADC) maps in the middle coronal slices of lungs (n = 10). ADC was measured immediately before and after two recruitment maneuvers, which were separated from each other with a wait period (8-44 min). We detected a statistically significant decrease in mean ADC after each recruitment maneuver. The relative ADC change was -21.2 ± 4.1 % after the first maneuver and -9.7 ± 5.8 % after the second maneuver. A significant relative increase in mean ADC was observed over the wait period between the two recruitment maneuvers. The extent of this ADC buildup was time dependent, as it was significantly related to the duration of the wait period. The two postrecruitment ADC measurements were similar, suggesting that the lungs returned to the same state after the recruitment maneuvers were applied. No significant intrasubject differences in ADC were observed between the corresponding PEEP levels in two rats that underwent three repeat maneuvers. Airway pressure tracings were recorded in separate rats undergoing one PEEP maneuver (n = 3) and showed a significant relative difference in peak inspiratory pressure between pre- and poststates. These observations support the hypothesis of redistribution of alveolar gas due to recruitment of collapsed alveoli in presence of atelectasis, which was also supported by the decrease in peak inspiratory pressure after recruitment maneuvers.     

Regional correlation of emphysematous changes in lung function and structure: a comparison between pulmonary function testing and hyperpolarized MRI metrics

Regional and global relationships of lung function and structure were studied using hyperpolarized 3He MRI in a rat elastase-induced model of emphysema (n = 4) and healthy controls (n = 5). Fractional ventilation (r) and apparent diffusion coefficient (ADC) of 3He were measured at a submillimeter planar resolution in ventral, middle, and dorsal slices 6 mo after model induction. Pulmonary function testing (PFT) was performed before MRI to yield forced expiratory volume in 50 ms (FEV??), airway resistance (R(I)), and dynamic compliance (C(dyn)). Cutoff threshold values of ventilation and diffusion, r* and ADC*, were computed corresponding to 80% population of pixels falling above or below each threshold value, respectively. For correlation analysis, r* was compared with FEV??/functional residual capacity (FRC), R(I) and C(dyn), whereas ADC* was compared with FEV??/FRC, total lung capacity (TLC), and C(dyn). Regional correlation of r and ADC was evaluated by dividing each of the three lung slices into four quadrants. C(dyn) was significantly larger in elastase rats (0.92 ± 0.16 vs. 0.61 ± 0.12 ml/cmH?O). The difference of R(I) and FEV?? was insignificant between the two groups. The r* of healthy rats was significantly larger than the elastase group (0.42 ± 0.03 vs. 0.28 ± 0.06), whereas ADC* was significantly smaller in healthy animals (0.27 ± 0.04 vs. 0.36 ± 0.01 cm2/s). No systematic difference in these quantities was observed between the three lung slices. A significant 33% increase in ADC* and a significant 31% decline in r* for elastase rats was observed compared with a significant 51% increase in C(dyn) and a nonsignificant 26% decline in FEV??/FRC. Correlation of imaging and PFT metrics revealed that r and ADC divide the rats into two separate clusters in the sample space.     

Evaluation of collimators' response: round and hexagonal holes in parallel and fan beam

With regard to the different requirements, various collimators are widely employed within nuclear medicine systems in order to evaluate the metabolism of organs as well as improve the contrast of images and better diagnosis. In this study, Fan Beam (FB) and Parallel Beam (PB) collimators in the shapes of round and hexagonal holes have been investigated and compared based on the Geometric Efficiency (G), Geometric Resolution (R(c)), Total Resolution (R(t)), FWHM and Scatter and Penetration (S?+?P) components using the Monte Carlo simulation. Calculations demonstrated that the G was improved with the increase in the distance between point source and collimator face (z). In contrast, the G was reduced with an increase in the angle of slant hole. In the FB collimator, the R(c) and R(t) were increased when the increase in the hole angle and/or the distance. The simulated results indicated in both collimators with the increase in z, a) the FWHM was increased as well as the peak of the PSF curve was decreased, and b) the S?+?P amounts decreased, but in the distinct z, the FWHM of the FB collimator is better than that of the PB collimator. It is shown that the results were in agreement with the ADAC company data. Also, Benchmark for measuring ADAC company demonstrated the calculated and simulated amounts of the R(c) and R(t) with round and hexagonal holes shapes had maximum and minimum average relative differences equal to?-7.6% for PB and 1% for FB, respectively.