جستجوی مقالات مرتبط با کلیدواژه "stability" در نشریات گروه "پزشکی"

Preparing patients for emergency surgeries requires accurate consideration of their clinical condition and medical history to avoid potential hemodynamic instability and compromise the immune system. This study aims to compare the effects of dexmedetomidine and magnesium sulfate infusions in maintaining stable hemodynamics during emergency orthopedic surgery. 

The present study was conducted as a randomized and double-blind clinical trial with the participation of 80 patients who were candidates for an emergency orthopedic surgery during 2021. Magnesium sulfate was administered as an intravenous bolus at a loading dose of 50 mg/kg over 10 minutes, followed by a continuous infusion at a rate of 15-20 mg/kg/hour. Dexmedetomidine was administered as an intravenous bolus at a loading dose of 1 mcg/kg over 10 minutes, followed by a continuous infusion at a rate of 0.2-0.7 mcg/kg/hour, depending on patient response. These infusions were initiated 15 minutes before induction of anesthesia and continued until the end of surgery. All drugs (dexmedetomidine and magnesium sulfate) were diluted in a 50-cc syringe and infused. The hemodynamic status (diastolic blood pressure (DBP), systolic blood pressure (SBP) mean arterial pressure (MAP) and heart rate (HR)) of the patients between the two groups was recorded and finally compared with each other. 

The hemodynamic status (DBP, SBP, MAP and HR) between the two groups at all (perioperative time) times were without significant statistical differences (P˃0.05). 

Both dexmedetomidine and magnesium sulfate are effective and safe options for achieving hemodynamic stability during emergency orthopedic surgery.

Given the increasing use of chlorine-based disinfectants and concerns regarding their shelflife and persistence on the surface, the present study investigated the effect of environmental conditions on the stability of commercial solutions stored under different conditions. This study assessed the stability of 0.05%, 0.5%, and 1% sodium hypochlorite solutions at pH levels of 5, 7.5, and 10 stored at temperatures of 4 ° C, 25 ° C, and 45 ° C using iodometric titration at 0, 15, 30, and 60 days after preparation. Eighty-seven solutions from three commercial brands (Brand A, Brand B, and Brand C) were prepared based on experimental design and response surface modeling (RSM) using Box-Behnken factorial design (BBD). The results revealed that the linear coefficient effects of all factors (temperature, storage time, pH, and initial concentration) were statistically significant (P<0.05). However, no significant differences were found among the three commercial brands (P=0.307). A negative correlation was observed between free available chlorine (FAC) and storage time. Solutions with a higher initial concentration (1%) tended to have lower stability. Higher temperatures also contributed to the instability of the solutions. Moreover, a gradual decrease was observed in the pH over time, and the lowest stability was detected at a neutral pH of 7.5. These findings suggest that environmental conditions (e.g., temperature, storage duration, pH, and initial concentration) significantly affect the stability of chlorine in the solutions. Therefore, these factors should be considered when using chlorine and storing chlorine-based disinfectants (CBDs) to ensure optimal performance and effectiveness.

Laccase enzymes are widely used in industrials and therefore achievement to the resources of this enzyme with high thermostability is obligatory. Accordingly, a deeper investigation for understanding the structure and function of PoxA1b from Pleurotus ostreatus, as a fungal enzyme with the possible desired conditions, was accomplished by using in-silico methods. Our study led to modeling a tertiary structure of the enzyme with 72% identity to the laccase from Trametes sp. AH28-2, with high quality. Moreover, structural stability of modeled enzyme compared to laccase from Pycnoporus cinnabarinus (LPC), were proved during 20 ns at 300 and 333K. Interestingly, this data showed that the modeled enzyme is more stable than LPC at 333 K. On the other hand, interaction assay of PoxA1b and LPC with benzo[a]pyrene (BaP), as a Polycyclic aromatic hydrocarbons (PAHs), revealed suitable affinity for both of them with -9.1 and -8.8 of binding energy, respectively. Taken together, these data show that both laccase from Pleurotus ostreatus and Pycnoporus cinnabarinus are stable until 60 °C with suitable affinity to substrate. Bearing in mind, PoxA1b is a favorable candidate for industrial and environmental applications, especially in PAH detoxification.

In this study, ocular drug delivery systems with a dispersed lipid liquid crystal (cubosomes) containing fluorometholone were used for sustained release and increased permeability to the eye.

To obtain the best Cubosomes, 6 formulations (F) were prepared. To prepare the F1, glycerol monooleate (GMO) and water containing fluorometholone were vortexed.  After one week, when the liquid crystal gel formed, 0.5 g of the liquid crystal gel was added to 9.5 g of a 1% (w/w%) aqueous solution of Polaxamer F-127, and the mixture were homogenized and sonicated.

The data showed that increasing the weight of gel from 0.5 g to 1.0 g (F2) did not result in a significant increase in drug loading, indicating that increasing the GMO concentration did not affect drug loading. The addition of cyclodextrin to the formulation (F3), along with an increase in cyclodextrin concentration from a molar ratio of 5:1 to 10:1 (F4), did not create a significant alternation in drug loading. Furthermore, the addition of phosphatidyl choline (PC) to the GMO (F5) did not cause a significant change in drug loading. Finally, in formulation F6 ( in which GMO, Polaxamer, and the drug was dissolved in ethanol, the ethanol was removed, and the mixture was dispersed in water) the resulting cubosomes showed a higher drug loading efficiency compared to other formulations. Accelerated stability studies of optimal formulation (F6) according to the ICH Q1A(R2) guideline demonstrated no significant changes in physical characterization and in-vitro release evaluation, indicating complete formulation stability.

Cubosomes can be used as suitable carriers for fluorometholone delivery to eye.

 This study assessed the stability of the outcomes after mandibular incisor extraction (MIE) using intercanine width and peer assessment rating (PAR) scores in orthodontic patients.

PubMed, Cochrane Library, Science Direct, Google Scholar, Ovid, and SciELO were systematically searched without restrictions until August 2022. A risk of bias assessment was performed using Newcastle-Ottawa Scale (NOS). The Grading of Recommendations, Assessment, Development, and Evaluation tool was used to assess the quality of evidence. Random effects meta-analysis was performed using RevMan software.

Seven retrospective studies met the inclusion criteria and were included. Meta-analysis identified a statistically significant reduction in intercanine width with MIE after the retention period. The mean difference in post-retention changes concerning intercanine width (MD=0.14, 95% CI: -2.17–1.89; P<0.00001) was significantly higher in premolar extraction (PE) compared to incisor extraction and significantly less in non-extraction compared to incisor extraction (MD=0.72, 95% CI: -0.59–2.03; P<0.00001). Improvements in PAR scores from the start of treatment to the retention period indicated a high outcome standard (>70%) with MIE treatment, with no significant difference in the reduction percentage compared to premolar and non-extraction groups.

 With the existing retrospective studies of limited evidence, treatment outcomes with MIE were found to show good improvements in PAR scores. Some reduction in the intercanine width was evident after the retention period, which was observed even with the other two treatment modalities that were compared. Hence, with careful evaluation, MIE could be considered a valid treatment option.

The aim of this study was to develop an optimized formulation for labeling a third-generation bisphosphonate, zoledronic acid with [99mTc] Tc to achieve the best formulation in preparing an ideal skeletal radiotracer.  Radio-complex yield and purity, stability, biodistribution and imaging in normal rat were investigated.  

The samples containing different amounts of zoledronic acid, ascorbic acid and stannous chloride were prepared and labeled with [99mTc]technetium pertechnetate. TLC methods were used to determine the radiochemical purity. The stability was determined in saline and human serum solutions. Lipophilicity was calculated by measuring radio-complex that was divided between organic and aqueous phases. In vitro bone affinity was studied through hydroxyapatite binding assays. Considering the decomposition of radioactivity, biodistribution of radio-complex was assessed based on the percentage of injected activity per gram of organ (% IA/g).

[99mTc]Tc-zoledronic acid was prepared easily with high yield while 100 µg, 0.34 µmol of zoledronic acid as a ligand and 100 µg, 0.44 µmol SnCl2 as a reducing agent were used. Radiochemical purity of radio-complex was more than 99% with specific activity of 8050 MBq/µmol. The radio-complex showed rapid blood washout along with high bone uptake value (4.53 ± 0.14 % IA/g at 2 h post injection).

Under optimized condition, [99mTc]Tc-zoledronic acid was prepared with high purity and stability together with high bone affinity and rapid blood clearance, make this radio-complex an ideal agent with great potential for skeletal imaging.

Medicinal products of plant origin have long been considered the most affordable and accessible sources to treat different health problems. Bromelain (Br) is a mixture of enzymes derived from pineapple (Ananas comosus L.) with a wide field of applications including medicine, health, food, and cosmetics. Br has various therapeutic effects, such as antimicrobial, antioxidant, anticancer, wound healing, burn treatment, pain relief, anti-inflammatory, inhibition of platelet aggregation, and fibrinolytic activity. On the other hand, most proteins are susceptible to denaturation and structural changes that may reduce their activities. Encapsulation of drug molecules into nanoparticles (NPs) could increase their stability, bioavailability, and overcome other challenges in drug delivery and therapy. This review aimed to highlight various Br nano-formulations approaches, toward the improvement of Br therapeutic efficiency.

Today, the non-covalent PEGylation methods of protein pharmaceuticals attract more attention and possess several advantages over the covalent approach. In the present study, Amino Acid-mPEGs (aa-mPEGs) were synthesized, and the human Growth Hormone (hGH) stability profile was assessed in their presence and absence.

aa-mPEGs were synthesized with different amino acids (Trp, Glu, Arg, Cys, and Leu) and molecular weights of polymers (2 and 5 KDa). The aa-mPEGs were analyzed with different methods. The physical and structural stabilities of hGH were analyzed by SEC and CD spectroscopy methods. Physical stability was assayed at different temperatures within certain intervals. Molecular dynamics (MD) simulation was used to realize the possible mode of interaction between protein and aa-mPEGs. The cell-based method was used to evaluate the cytotoxicity.

HNMR and FTIR spectroscopy indicated that aa-mPEGs were successfully synthesized. hGH as a control group is known to be stable at 4 °C; a pronounced change in monomer degradation is observed when stored at 25 °C and 37 °C. hGH:Glu-mPEG 2 kDa with a molar ratio of 1:1 to the protein solution can significantly increase the physical stability. The CD spectroscopy method showed that the secondary structure of the protein was preserved during storage. aa-mPEGs did not show any cytotoxicity activities. The results of MD simulations were in line with experimental results.

This paper showed that aa-mPEGs are potent excipients in decreasing the aggregation of hGH. Glu-mPEG exhibited the best-stabilizing properties in a harsh environment among other aa-mPEGs.

α-Amylases catalyze the starch hydrolysis reaction and are widely used in starch processing industries. Despite the high demand for the use of α-amylase in various industries, most α-amylases do not have the required functional characteristics such as proper activity, temperature and pH compatibility, as well as temperature stability. In this regard, ionic liquids are widely used today as co-solvents to improve enzymes' activity, stability, and selectivity.

Activity, optimum temperature, optimum pH, and thermal stability of B. subtilis α-amylase were investigated in the presence of 1-ethyl-3-methylimidazolium acetate. Structural changes in the presence of [EMIm][Ac] were examined using intrinsic fluorescence spectroscopy.

The activity of α-amylase and Vm increased in the presence of 0.4 M of [EMIm][Ac] while Km decreased. The optimum temperature and pH did not change in the presence of [EMIm][Ac] compared to its absence. At 40 and 50 °C, the inactivation rate of α-amylase in the presence of both concentrations of 0.4 and 1 M of [EMIm][Ac] is the same as in its absence. However, the rate of inactivation at 60 and 70 °C is higher than that in the absence of [EMIm][Ac]. The results of intrinsic fluorescence spectroscopy confirmed the structural changes in the presence of [EMIm][AC].

[EMIm][Ac] can be used to increase the activity of B. subtilis α-amylase without affectingthe optimal temperature and pH parameters. Moreover, [EMIm][Ac] relatively improves the thermal stability of the α-amylase

Recent coronavirus pandemic and its global socio-economic impact has re-emphasized the need for safe, fast, and efficient delivery of vaccines for humankind. With advent of technological advances, and to improve patient acquiescence, several techniques for fast, effective, and safe delivery of vaccines have been researched and published in the literature in last three decades. These delivery enhancement techniques include but are not limited to electroporation, microneedles (MN), ultrasound, iontophoresis, etc. This review aims at discussing the current research undergoing in vaccine delivery, specifically focusing on microneedles assisted, the historical background of microneedles and their introduction to drug delivery area, and a special focus on formulation challenges and stability in these systems. The review also sheds light on regulatory challenges one must keep in mind for bringing a successful microneedles-based vaccine delivery into market as well as a snapshot of current commercially available microneedles-based products in cosmetic and pharmaceutical industry.

Food security, which is considered to be a public health-related socioeconomic factor, ensures the health of society's people and plays a significant role in improving governance. This concept is closely related to the concept of stability of food. The stability of food means that there should be adequate, quality, and nutritious food for all human beings, in all places and at all times, and no factor should prevent this important issue. Stability in food production and supply is at the heart of food security and makes food systems resilient in times of crisis. The negative impact of climate change on agricultural production, intensified inflationary trends, high food prices, increasing food waste, increasing the need for food imports, and, more significantly, ongoing international sanctions make it difficult to access affordable food and pose challenges to Iran's food security. Moreover, the COVID-19 crisis has reduced the incomes of families and government by intensifying economic pressures on government incomes as well as rising unemployment, which has directly exacerbated food insecurity. The link between indicators of food stability and food security in Iran is the subject of this article. The key indicators selected are the percent of arable land equipped for irrigation, the cereal imports dependency ratio, the value of food imports over total merchandise exports, per capita food production variability, and, per capita food supply variability. Results show Iran is vulnerable to the arable land equipped for irrigation, food imports over total merchandise exports, and the cereal imports dependency ratio while being resilient per capita food production and food supply variability.

Thiolated hyaluronic acid (HA) with interesting properties, such as muco-adhesiveness, enzyme inhibitory, permeation enhancing, and release controlling properties can be applied for drug delivery in various diseases like mucositis. The purpose of this study was to evaluate the stability and toxicity of thiol modified HA by the aid of L-cysteine ethyl ester hydrochloride (Cys) named (HA-Cys) and allantoin (Alla) incorporated HA-Cys (HA-Cys-Alla) to reveal their potential for the future treatment of mucositis.

The HA modification and drug incorporation were investigated using FTIR spectroscopy. The evaluation of in vitro cytotoxicity on Caco-2 cell line by means of MTT assay and in vivo toxicity by measuring the hematological and biochemical parameters in rats were performed. The appearance stability of HA-Cys and HA-Cys-Alla was evaluated at room and refrigerator temperatures over time. In addition, the stability of HA-Cys and HA-Cys-Alla subjected to heating and cooling, freeze-thaw, centrifugal forces, as well as the pH stability under the above-mentioned conditions were also investigated.

The results indicated that the synthesized HA-Cys and HA-Cys-Alla with pseudo-plastic rheological behavior demonstrated excellent stability at refrigerator temperature. Although HA-Cys showed good stability, the HA-Cys-Alla revealed color change at room temperature. Moreover, despite no much resistance of HA-Cys and HA-Cys-Alla against the heating-cooling test, the samples exhibited good resistance against freeze-thaw and centrifugal forces. Also, convenient pH stability and high in vitro and in vivo biocompatibility were observed.

The low in vitro and in vivo toxicity and convenient stability of HA-Cys-Alla has introduced it as a proper candidate for future clinical applications.

The present study aimed to systematically explore available literature on the possible impact of photobiomodulation (PBM) therapy on the stability and success of orthodontic mini-implants.

A comprehensive electronic search was conducted in PubMed, ISI Web of Science, Scopus, Cochrane and Embase databases for human and animal studies published until July 2021. Two independent researchers reviewed the studies based on specific eligibility criteria.

15 studies were included in the systematic review after a comprehensive search. Ten studies were included in the meta-analysis. Four were human RCT studies that evaluated the stability with Preriotest. Three other human RCT studies and two animal studies had evaluated the Implant stability quotient (ISQ). Two human RCTs that had evaluated displacement of mini-implants were also analyzed. The analysis of Periotest stability results showed a positive effect of PBM on mini-implant stability at 30 and 60 days after implantation (P < 0.05). In human studies using the ISQ method, a slight improvement was seen in the PBM groups; however, this was not statistically significant (CI = -1.92-2.70, SMD = 0.39). In studies that examined the displacement of mini-implants, no statistically significant difference was observed between irradiated and non-irradiated groups (CI = -1.92-2.70, SMD = 0.03). According to the results of animal studies, which had used the ISQ method, the use of laser was statistically effective in increasing the stability of mini-implants (SMD = 1.43, CI = 1.00–1.85).

PBM therapy can be suggested as an adjunctive clinical method to improve the stability of mini-implant treatment. Further well-designed clinical studies can help establish evidence-based dosing and irradiation protocols.

The application of low-level laser therapy (LLLT) and some medications have been shown to accelerate bone formation in the rapid palatal expansion (RPE). A combination of these two therapeutic modalities may reduce the time required for the retention period. This study sought to assess the effects of simvastatin and LLLT, alone and combined, on sutural bone formation in rats.

Sixty male Wistar rats averagely weighing 150 g were divided into five groups (n=12) of control (group 1), 5 mg simvastatin (group 2), 10 mg simvastatin (group 3), LLLT (group 4), and LLLT plus 10 mg simvastatin (group 5). The expansion appliance was placed in the parietal bone in all groups. One week after placing the appliance, the spring was fixed with Duralay acrylic resin to serve as a retainer during the rest of the experiment. The rats were sacrificed after 30 (for biomechanical and computed tomography [CT] assessments) or 60 days (for biomechanical, CT, and immunohistochemical [IHC] assessments).

Groups 3 and 4 showed a significant improvement in osteogenesis (confirmed by CT findings, histological analysis, and biomechanical test) compared to the control group. Group 5 was significantly superior to all other groups in terms of all parameters (P<0.001). Group 2 and the control group were not significantly different (P>0.05).

Although LLLT, simvastatin treatment, and the combination of both significantly improved sutural bone formation in rats compared to the control group, the combined treatment showed significantly superior clinical results compared to other interventions.