Evaluation of the Role of the KRAS Gene Polymorphism LCS6 (rs61764370) in Iraqi Women with Ovarian Cancer.

In carcinogenesis, KRAS is an essential oncogene that plays a key function. The polymorphism of rs61764370 is a candidate for cancer susceptibility in KRAS3' untranslated region. The current study aimed to determine the role and impact of the KRAS gene polymorphism (rs61764370 T>G) on the risk of ovarian cancer development in the Iraqi population. In total, 84 ovarian cancer patients and 28 ovarian benign tumors were involved in a case-control study. DNA extraction from the formalin-fixed/paraffin-embedded tissues, followed by the sequencing of PCR products was carried out in genetic analysis for the detection of the KRAS polymorphism (rs61764370 T>G). The results showed that the frequencies of the KRAS gene polymorphism (rs61764370) in ovarian cancer patients were 78 (92.85%) and 6 (7.15%) with genotypes homozygote TT and heterozygote TG, respectively. These corresponding values in patients with benign ovarian tumors were 25 (89.3%) and 3 (10.7%) with homozygote TT and heterozygote TG, respectively. None of the patients either with malignant or benign tumors have been detected with homozygote genotype GG. Genotype frequency of the TT and TG showed that the heterozygote TT genotype vs. TG and T allele vs. G allele were more frequent in malignant and benign tumors (P≤0.01). Statistically, there was no association between the KRAS polymorphism and the clinical characteristics of ovarian cancer patients, such as age, family history, menopause, histological type, tumor size, or tumor stage. In conclusion, a significant association was found between rs61764370 and the risk of ovarian cancer in the Iraqi population, particularly those with genotypes homozygote TT. On the other hand, genotypes had no relationship with any of the clinical characteristics of ovarian cancer patients. Additional well-designed studies with larger sample sizes are recommended to validate the precise role of KRAS LCS6 variations in ovarian cancer risk.

Intra-Arterial Thrombolysis after Unsuccessful Mechanical Thrombectomy in the STRATIS Registry.

BACKGROUND AND PURPOSE: Recent data suggest that intra-arterial thrombolytics may be a safe rescue therapy for patients with acute ischemic stroke after unsuccessful mechanical thrombectomy; however, safety and efficacy remain unclear. Here, we evaluate the use of intra-arterial rtPA as a rescue therapy in the Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) registry. MATERIALS AND METHODS: STRATIS was a prospective, multicenter, observational study of patients with acute ischemic stroke with large-vessel occlusions treated with the Solitaire stent retriever as the first-line therapy within 8 hours from symptom onset. Clinical and angiographic outcomes were compared in patients having rescue therapy treated with and without intra-arterial rtPA. Unsuccessful mechanical thrombectomy was defined as any use of rescue therapy. RESULTS: A total of 212/984 (21.5%) patients received rescue therapy, of which 83 (39.2%) and 129 (60.8%) were in the no intra-arterial rtPA and intra-arterial rtPA groups, respectively. Most occlusions were M1, with 43.4% in the no intra-arterial rtPA group and 55.0% in the intra-arterial rtPA group (P = .12). The median intra-arterial rtPA dose was 4 mg (interquartile range = 2-12 mg). A trend toward higher rates of substantial reperfusion (modified TICI ≥ 2b) (84.7% versus 73.0%, P = .08), good functional outcome (59.2% versus 46.6%, P = .10), and lower rates of mortality (13.3% versus 23.3%, P = .08) was seen in the intra-arterial rtPA cohort. Rates of symptomatic intracranial hemorrhage did not differ (0% versus 1.6%, P = .54). CONCLUSIONS: Use of intra-arterial rtPA as a rescue therapy after unsuccessful mechanical thrombectomy was not associated with an increased risk of symptomatic intracranial hemorrhage or mortality. Randomized clinical trials are needed to understand the safety and efficacy of intra-arterial thrombolysis as a rescue therapy after mechanical thrombectomy.

Kinetics and mechanism of degradation of epothilone-D: an experimental anticancer agent.

The objective of this study was to investigate the stability and the degradation pathway of epothilone-D (Epo-D), an experimental anticancer agent. In pH range 4-9, Epo-D displayed pH-independent stability and the highest stability was observed at pH 1.5-2 where its thiazole group is protonated. Increasing the pH >9 or <1.5 resulted in an increase in the degradation rate. Epo-D contains an ester group that can be hydrolyzed. The formation of the hydrolytic product was confirmed by the nuclear magnetic resonance (NMR), fast atom bombardment mass spectroscopy and liquid chromatography/mass spectroscopy/mass spectroscopy techniques. The largely sigmoidal pH-rate profile is not consistent with the normal pH dependency of ester hydrolysis involving an addition/elimination mechanism. Hence, a hydrolysis mechanism through a carbonium ion was suggested. At pH 4 and 7.4, no buffer catalysis was observed (0.01, 0.02, and 0.05 M buffers) and no significant deuterium kinetic solvent isotope effect was noted. The degradation was very sensitive to changes in the dielectric constant of the solvents as significant enhancement in the stability was observed in buffer-acetonitrile and 0.1 M (SBE)7m-beta-cyclodextrin solutions compared with just buffer, suggesting that the rate-determining step in the degradation pathway involved formation of a polar transition state. Mass spectral analysis of the reaction run in 18O water was consistent with incorporation of the 18O in the alcohol hydroxyl rather than the carboxylate group. These observations strongly support the carbonium ion mechanism for the hydrolysis of Epo-D in the pH range 4-9. A pKa value of 2.86 for Epo-D was estimated from the fit of the pH-rate profile. This number was confirmed independently by the changes in ultraviolet absorbance of Epo-D as a function of pH (pKa 3.1) determined at 25 degrees C and the same ionic strength.

Degradation of NSC-281612 (4-[bis[2-[(methylsulfonyl)oxy]ethyl]amino]-2-methyl-benzaldehyde), an experimental antineoplastic agent: effects of pH, solvent composition, (SBE)7m-beta-CD, and HP-beta-CD on stability.

NSC-281612 (4-[bis[2-[(methylsulfonyl)oxy]ethyl]amino]-2-methyl-benzaldehyde, 1), is a chemically unstable, poorly water soluble, experimental antineoplastic agent. The saturated solubility in water at 25 degrees C was determined as approximately 30 microg/mL. In the pH range 2-11, 1 displayed pH-independent stability (t(50) was around 24 hr). However, an increase in the degradation rate was observed at pH 12. The hydrolysis of the methane sulfonate groups to the corresponding hydroxyl groups was the major degradation pathway in water in the absence of buffers and added halide ions. In phosphate buffer solutions without sodium chloride, phosphate degradants appear to be formed in addition to the mono- and dihydroxy degradants. Additional degradants, the mono- and dichloro degradation products, were formed when the ionic strength of the solution was adjusted with sodium chloride. When bromide and iodide ions were added, the corresponding mono- and dihalides were formed. The chloro compounds subsequently underwent further degradation to the hydroxy products. A deuterium kinetic solvent isotope effect study showed that water was minimally involved in the rate-determining step. The addition of either (SBE)(7m)-beta-cyclodextrin (CD) or HP-beta-CD resulted in a significant enhancement in drug solubility and stability. The apparent binding constants for HP-beta-CD and (SBE)(7m)-beta-CD were 1,486 and 2,740 M(-1), respectively. The stability of 1 in the presence of 0.1 M HP-beta-CD and (SBE)(7m)-beta-CD was enhanced 9- and 15-fold, respectively. Thus, (SBE)(7m)-beta-CD displayed better solubilization and stabilization efficacy than HP-beta-CD.

Formulating and stability of benzodiazepines in a new lipid emulsion formulation.

The objective of the current study was to evaluate the novelty of a new lipid emulsion formulation containing 30% oil phase as a drug delivery system. Therefore different benzodiazepines (BZs), namely diazepam, tetrazepam, clonazepam and lorazepam, were incorporated into this emulsion formulation. This lipid emulsion formulation showed enhanced solubilization capacity as 10 mg/ml, 10 mg/ml, 0.9 mg/ml, and 1.8 mg/ml formulations for diazepam, tetrazepam, clonazepam, and lorazepam were achieved, respectively. Incorporating the drugs into the lipid emulsion did not alter its physicochemical properties. Also the free and the drug emulsion formulations displayed good physical stability after autoclaving and after around one year of storage at shelf, as no changes in the physicochemical properties were observed. Most drugs also showed stable behavior after autoclaving and after approximately 1 year of storage at shelf. The only exception was lorazepam, as only around 50% of the drug was still intact after autoclaving.

Development of a novel parenteral formulation for tetrazepam using a lipid emulsion.

A novel parenteral formulation for tetrazepam (10 mg/ml) was developed using lipid emulsions. This formulation utilized a new lipid emulsion formulation, which was developed by changing the polarity of the oil phase. It was found that increasing the polarity of the oil phase resulted in enhanced solubility of tetrazepam. Tetrazepam showed higher solubility in a mixture of castor oil and middle-chain triglycerides (MCTs) (1:1) than in any other oil investigated. This mixture resulted in low interfacial tension and moderate viscosity, which seemed to be the optimum oil phase. In addition, to increase the concentration of tetrazepam, an emulsion formulation containing 30% oil phase was produced and optimized. The drug-free emulsion formulation showed fine particle sizes with an imperceptible change in physicochemical properties after more than 2 years on the shelf. As a result, it was possible to produce a parenteral emulsion formulation containing 10 mg/ml tetrazepam. No change in the physicochemical properties of the emulsion was observed after the addition of tetrazepam. The tetrazepam emulsion showed stable behavior during the autoclaving process and good shelf stability for at least 10 months as well. Tetrazepam itself also displayed good stability during the autoclaving process and also showed good shelf stability in this emulsion formulation.

Middle-school students of United Arab Emirates: effects of heterogeneous small group work on attitudes toward mathematics.

This study compared the effects of two instructional strategies, small heterogeneous cooperative learning experience versus lecture and discussion, on students' attitudes toward mathematics. 54 boys and 57 girls in Grade 8 of four middle-school mathematics classes participated. Two classes (57 students) were taught using a cooperative learning method and the other two classes (54 students) were taught using traditional lecture and discussion. Differences between attitudes of boys and girls were also investigated and discussed in the light of Arabic culture. The results suggested that cooperative learning might be a valuable method with which to teach mathematics concepts to boys.

Influence of the degree of polymerization on the behavior of cellulose during homogenization and extrusion/spheronization.

The study objective was to investigate the influence of the degree of polymerization (DP) of cellulose materials (microcrystalline cellulose [MCC] and powder cellulose [PC]) on the behavior of these materials during homogenization and extrusion/spheronization processes. Suspensions of the cellulose types with different DP values were homogenized using a high-pressure homogenizer. The particle size, agglomeration index, and apparent viscosity of these suspensions was determined at different times after pouring. Additionally, these different cellulose types were processed into pellets using the extrusion/spheronization method, and the water content and power consumption as a function of the DP were determined. Cellulose types with a high DP value showed greater particle size after homogenization than the types with a low DP value. In contrast, no relevant relationship between the apparent viscosity and DP could be observed. During the extrusion process, water content in the extrudate and pellet porosity were increased as the DP was increased for the extrudates produced at the same level of power consumption. MCC types with various DPs compared with PC provided a novel way of understanding the role of cellulose in the extrusion process. The DP showed a remarkable influence on the physicochemical properties of the cellulose materials and, consequently, on the behavior of these materials during the extrusion/spheronization process. It is postulated that the sponge model is more appropriate for the cellulose type with high DP (PC), whereas the gel model is more applicable to cellulose types with lower DP (MCC).

Lipid emulsions as a novel system to reduce the hemolytic activity of lytic agents: mechanism of the protective effect.

The hemolytic activity of sodium oleate, a high lytic agent, was investigated in different surfactant solutions and lipid emulsion formulations. A new explanation of the protective function of these systems is proposed. It was found that the hemolytic activity of the lytic agent was greatly decreased in solutions and/or dispersions with the surfactant Cremophor EL, Solutol H16 and phospholipids, which can usually build a micellar or liposomal structure. In the case of F68, where the micelle formation is still controversial, the hemolytic activity of the lytic agent was practically not affected and complete hemolysis was observed. In contrast to this, all emulsion formulations, independent of the emulsifier type, showed a stable erythrocyte behavior. Additionally, in the case of lipid emulsions only, a larger amount of the lytic agent could be added without any remarkable increase in the hemolytic activity. As an explanation for these effects it is proposed that the lytic agent is either incorporated into the lipophilic core or intercalates between the emulsifier molecules at the interface. This decreases the direct contact of the lytic agent with the erythrocyte membrane. As a result, the erythrocytes will effectively be protected from hemolytic damage, which can otherwise be induced by such substances.

Physicochemical properties of chitosan-lipid emulsions and their stability during the autoclaving process.

A new positively charged, submicronized fat emulsion with appropriate stability during the autoclaving process was developed. Only the emulsions prepared with a combination of ABA block co-polymer (F68) and chitosan were stable enough to resist the thermic shock induced by autoclaving sterilization. The results indicate that a mixed film consisting of the ABA block co-polymer and chitosan molecules was formed at the o/w interface with an overall positive surface charge. Conversely, a combination between chitosan with phospholipids and/or with a mixture of phospholipids with ABA block co-polymer showed a phase separation during autoclaving. A chitosan type with a low viscosity was used which was intended for a possible use in the ocular and parenteral application. An experimental factorial design 32 was used to investigate the effect of chitosan and F68 concentrations on the physicochemical properties of the system and consequently their influence on the stability of emulsions during autoclaving. Both size and surface charge of emulsions were significantly affected as a function of the chitosan concentration. Formulation with a mean particle size ranging from 125 to 130 nm and with a positive surface charge of 20-23 mV was achieved. Moreover, the chitosan emulsions were autoclaved without a significant change in their particle size. However, increasing the concentration of chitosan needs a higher amount of F68 in order to achieve stable emulsions during autoclaving. This may be due to the interaction between the positively-charged chitosan and the negatively-charged free fatty acids, which are contained in the oil phase (castor oil).

In vitro investigation of the effect of various isotonic substances in parenteral emulsions on human erythrocytes.

The hemolytic behaviour of human erythrocytes in parenteral emulsions containing various isotonizing substances (xylitol, sorbitol and glycerol) was studied. It was found that complete hemolysis of human erythrocytes occurred in parenteral emulsions with isotonic or isosmotic concentration of glycerol after 5 min, whereas emulsions which contained an isotonic concentration of xylitol or sorbitol did not show any hemolysis after 40 min. Conversely, formulations with different concentrations of glycerol in an isotonic solution of sorbitol did not show any hemolytic behaviour after 40 min. It appeared that all the hemolytic phenomena encountered in glycerol were of an isotonic character since hemolysis was totally prevented by the inclusion of an isotonic concentration of sorbitol. According to these in vitro results it seems that glycerol, a commonly used substance in commercial parenteral emulsions, may not be the best isotonizing substance.

Mixture experiments with the oil phase of parenteral emulsions.

The effects of the oil phase as a mixture (binary, ternary) on the emulsion droplet size were investigated. The binary trials were performed with the aid of simplex lattice design with constraints. Droplet diameter was evaluated in terms of the oil phase viscosity and the interfacial tension between oil phase and the aqueous phase. As a result it could be shown that increasing the oil phase viscosity as a function of castor oil concentration led to a greater increase in particle size. At the same time, decreasing the interfacial tension of the oil phase as a function of oleic acid or oleic alcohol was shown to have a negligible effect on the particle size of the dispersed phase. A further aim was to find out a formulation by using a ternary oil phase resulting in a stable emulsion which could pass the autoclaving process. It was ascertained that oleic acid as a part of the oil phase led to proper formulation showing a satisfactory stability.