Steric volume exclusion sets soluble protein concentrations in photoreceptor sensory cilia

Proteins segregate into discrete subcellular compartments via a variety of mechanisms, including motor protein transport, local binding, and diffusion barriers. This physical separation of cell functions serves, in part, as a mechanism for controlling compartment activity by allowing regulation of local protein concentrations. In this study we explored how soluble protein size impacts access to the confined space within the retinal photoreceptor outer segment signaling compartment and discovered a strikingly steep relationship. We find that GFP monomers, dimers, and trimers expressed transgenically in frog rods are present in the outer segment at 1.8-, 2.9-, and 6.8-fold lower abundances, relative to the cell body, than the small soluble fluorescent marker, calcein. Theoretical analysis, based on statistical-mechanical models of molecular access to polymer meshes, shows that these observations can be explained by the steric hindrance of molecules occupying the highly constrained spaces between outer segment disc membranes. This mechanism may answer a long-standing question of how the soluble regulatory protein, arrestin, is effectively excluded from the outer segments of dark-adapted rods and cones. Generally, our results suggest an alternate mode for the control of protein access to cell domains based on dynamic, size-dependent compartmental partitioning that does not require diffusion barriers, active transport, or large numbers of immobile binding sites.     

The effect of He-Ne and Ga-Al-As laser light on the healing of hard palate mucosa of mice

Low-level laser therapy (LLLT) has been used to accelerate wound healing, yet questions remain concerning its therapeutic applications. This study aimed to compare the healing efficacy of helium-neon (He-Ne) red light (laser) and gallium aluminum arsenide (Ga-Al-As) infrared lasers at two different doses on hard palate wounds. In a randomized controlled study, 75 adult male mice were divided into five groups of 15 each, after undergoing identical surgical procedures; a control group, with no laser irradiation; HD1 and HD2 groups, treated with He-Ne laser (wavelengths 632.8 nm, power 5 mW, and spot size 0.02 cm²) at doses of 4 J/cm² and 7.5 J/cm² respectively; and GD1 and GD2 groups, treated with Ga-Al-As laser (wavelengths 830 nm, peak power 25 mW, and spot size 0.10 cm²) at the doses of 4 J/cm² and 7.5 J/cm², respectively. Five animals from each group were killed on the third, seventh, and 14 days after surgery, and biopsies were made for histological analysis. On the 3rd and 7th day after the surgery, the number of polymorphonuclear cells (PMN) in HD1, HD2, GD1, and GD2 groups was significantly lower than that of the control group. On the 7th and 14th day, the fibroblasts and new blood vessels counts and collagen density fibers in HD1, HD2, GD1, and GD2 groups were also significantly higher than that of the control groups, and the fibroblast counts and collagen density fibers in HD1 and HD2 groups were higher than that of the GD1 and GD2 groups. LLLT with He-Ne laser compared to Ga-Al-As laser has a positive healing effect on hard palate gingival wounds in mice regardless of the radiation dose.     

The influence of the polymerization approach on the catalytic performance of novel porous poly (ionic liquid)s for green synthesis of pharmaceutical spiro-4-thiazolidinones

Although poly (ionic liquids) (PILs) have attracted great research interest owing to their various applications, the performance of nanoporous PILs has been rarely developed in the catalysis field. To this end, a micro–mesoporous PIL with acid–base bifunctional active sites was designed and fabricated by two different polymerization protocols including hydrothermal and classical precipitation polymerization in this paper. Based on our observations, hydrothermal conditions (high temperature and pressure) enabled the proposed sonocatalyst to possess a great porous structure with a high specific surface area (S_BET: 315 m² g⁻¹) and thermal stability (around 450 °C for 45% weight loss) through strengthening cross-linking. In a comparative study, the preferred nanoporous PIL was selected and utilized as the sonocatalyst in a multicomponent reaction of isatins, primary amines, and thioglycolic acid. In the following, a variety of new and known pharmaceutical spiro-4-thiazolidinone derivatives were synthesized at room temperature and obtained excellent yields (>90%) within short reaction times (4–12 min) owing to the substantial synergistic effect between ultrasound irradiation and magnetically separable catalyst.

Sustainable synthesize of a new mesoporous poly (ionic liquid) as acid–base bifunctional catalyst for environmental being preparation of monospiro derivatives has been developed.     

The effects of low-level laser irradiation on breast tumor in mice and the expression of Let-7a,miR-155, miR-21, miR125, and miR376b

Low-level laser therapy (LLLT) is a form of photon therapy which can be a non-invasive therapeutic procedure in cancer therapy using low-intensity light in the range of 450–800 nm. One of the main functional features of laser therapy is the photobiostimulation effects of low-level lasers on various biological systems including altering DNA synthesis and modifying gene expression, and stopping cellular proliferation. This study investigated the effects of LLLT on mice mammary tumor and the expression of Let-7a, miR155, miR21, miR125, and miR376b in the plasma and tumor samples. Sixteen mice were equally divided into four groups including control, and blue, green, and red lasers at wavelengths of 405, 532, and 632 nm, respectively. Weber Medical Applied Laser irradiation was carried out with a low power of 1–3 mW and a series of 10 treatments at three times a week after tumor establishment. Tumor volume was weekly measured by a digital vernier caliper, and qRT-PCR assays were performed to accomplish the study. Depending on the number of groups and the p value of the Kolmogorov-Smirnov test of normality, a t test, a one-way ANOVA, or a non-parametric test was used for data analyses, and p?<?0.05 was considered to be statistically significant. The average tumor volume was significantly less in the treated blue group than the control group on at days 21, 28, and 35 after cancerous cell injection. Our data also showed an increase of Let-7a and miR125a expression and a decrease of miR155, miR21, and miR376b expression after LLLT with the blue laser both the plasma and tumor samples compared to other groups. It seems that the non-invasive nature of laser bio-stimulation can make LLLT an attractive alternative therapeutic tool.     

The immunological benefit of higher dose N-acetyl cysteine following mechanical ventilation in critically ill patients

Background

Sepsis complication is a major cause of death in multiple trauma critically ill patients. Defensin (cysteine rich anti-microbial peptides), as an important component of immune system, might play an important role in this process. There is also rising data on immunological effects of N-acetyl-cysteine (NAC), a commonly used anti-oxidant in oxidative stress conditions and glutathione (GSH) deficiencies. The aim of the present study was to evaluate the potential beneficial effects of NAC administration on multiple trauma patients with sepsis.

Methods

In a prospective, randomized controlled study, 44 multiple trauma critically ill patients who were mechanically ventilated and met the criteria of sepsis and admitted to the intensive care unit (ICU) were randomized into two groups . Control group received all standard ICU therapies and NAC group received intravenous NAC 3 gr every 6 hours for 72 hours in addition to standard therapies. Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA) scores, length of ICU stay, ICU mortality were recorded. Levels of serum Immunoglobulin M (IgM), Human β-Defensin 2 (HβD2) and GSH were assessed at baseline and 24, 72, 120 hours after intervention.

Results

During a period of 13-month screening, 44 patients underwent randomization but 5 patients had to be excluded. 21 patients in NAC group and 18 patients in control group completed the study. For both groups the length of ICU stay, SOFA score and systemic oxygenation were similar. Mortality rate (40% vs. 22% respectively, p = 0.209) and ventilator days (Mean ± SD 19.82 ± 19.55 days vs. 13.82 ± 11.89 days respectively, p = 0.266) were slightly higher for NAC group. IgM and GSH levels were similar between two groups (p = 0.325, 0.125 respectively), HβD2 levels were higher for NAC group (at day 3).

Conclusion

High dose of NAC administration not only did not improve patients’ outcome, but also raised the risk of inflammation and was associated with increased serum creatinine.     

Central venous pressure catheter for large-volume paracentesis in refractory ascites

Background and Aims

About 10 % of cirrhotic patients are unresponsive to sodium restriction and diuretics and develop refractory ascites. Such patients usually require recurrent large-volume paracentesis and lots of hospital admissions. Hereby, we introduce a method applying a central vein (CV) catheter for large-volume paracentesis in patients with refractory ascites in up to 4 days associated with sodium restriction and high dose of diuretics.

Methods

Non-tunneled triple lumen CV catheter was used to drain the ascites fluid of 30 cirrhotic patients. After precise percussion, the point of highest fluid accumulation was marked for puncture. Then, the skin and subcutaneous tissue were anesthetized. CV catheter set guide wire was entered into the peritoneal cavity and the dilator of the CV catheter set was passed through the guide wire and extracted after some rotations around its insertion site on the skin. The catheter was passed over the guide wire and the guide wire was extracted gradually from one of the lumens and fixed to the skin.

Results

Nineteen males and 11 females with mean (±SD) age of 59.4?±?11.7 years old underwent the procedure. A minimum of 9 and maximum of 29 L (12?±?6.6 L) ascites fluid drained during a minimum of 2 and maximum of 5 days of hospital stay. All catheters were patent during the drainage. None of the patients developed hemodynamic instability. Number of re-hospitalizations for paracentesis was 1.9 times during the following year. No complication occurred.

Conclusions

This technique is a simple noninvasive method that can be performed in the endoscopy unit or even at the patient’s bedside and may reduce the need for repeated admissions.     

Arthroscopic posterior cruciate ligament reconstruction by using hamstring tendon autograft and transosseous screw fixation: minimal 3 years follow-up

Background

The aim of this trial is to prospectively evaluate the outcomes of PCL reconstruction by means of quadruple hamstring tendon autograft with a double-fixation method at minimal 3-year follow-up.

Materials and methods

Only patients who underwent PCL reconstruction without any other concomitant injury were included in this study. A hamstring tendon graft is composed of a quadruple-stranded gracilis tendon and semitendinosus tendon about 10 cm in length. An arthroscopic technique via a two incision and a double-fixation method was applied. Clinical evaluations were performed for 52 patients. Clinical assessment of patients included the Lysholm knee scores, International Knee Documentation Committee (IKDC) scores, thigh muscle evaluation, and radiographic investigation.

Results

On the Lysholm knee score, 90 % of the patients displayed good or excellent rating in the final assessment. In the IKDC rating analyses, 60 % of the patients demonstrated 3–5-mm ligament laxity. For the IKDC final rating, 81 % were normal or nearly normal. Seventy-nine percent of the cases revealed less than a 10-mm difference in thigh girth between their reconstructed and contra lateral limbs.

Conclusion

Arthroscopic PCL reconstruction using quadruple hamstring tendon autograft provides acceptable outcomes at a minimum 3-year follow-up. The four-stranded hamstring tendon graft is suitable in graft size and results in minimal harvesting morbidity. We recommend that quadruple hamstring tendon graft be chosen for PCL reconstruction to achieve good ligament reconstruction. A double-fixation method which has been applied in this trial can be used to provide rigid fixation.