Comparison of coronary vessel sizing using coronary angiography versus intravascular ultrasound in Egyptian patients

Background: Coronary artery disease (CAD) is a leading causeof death worldwide. Intravascular imaging is an important toolin the arsenal of each interventional cardiologist. While angiographyprovides a two-dimensional image of a three-dimensionalstructure, intravascular imaging enhances understanding by providingdetailed cross-sectional images. This study aimed to investigatethe discrepancies in coronary vessel sizing between quantitativecoronary angiography (QCA) and intravascular ultrasound.Methods: This cohort study was conducted on 69 patients whowere referred for elective coronary angiography. Patients weresubjected to history taking, examination, blood samples, electrocardiogram(E.C.G.), and echocardiography. Then, a comparisonof each vessel’s luminal diameter by QCA and IVUS was done.Results: The study included 69 patients; The mean age was 54.7± 9.7. There was a statistically significant difference between thestudied vessels regarding the discrepancy between luminal diametersmeasured by IVUS and QCA. IVUS luminal diameter waslarger than QCA luminal diameter (the median difference in measuresof QCA and IVUS in the left main artery, LAD, LCX, and RCAwere -0.8, -0.55, -0.4, and -0.5 respectively). Furthermore, thereis a statistically significant difference between the studied vesselsregarding the presence of a difference >0.75 mm between theluminal diameters measured by IVUS and QCA (Difference >0.75mm in the left main artery, LAD, left circumflex and RCA were55.8%, 21.7%, 30.8%, and 15.4% respectively). Conclusion: Coronarylesions were underestimated by QCA in comparison to IVUSregarding luminal diameter, especially the left main (LM).

Mutations in codons 12 and 13 of K-ras exon 2 in colorectal tumors of Saudi Arabian patients: frequency, clincopathological associations, and clinical outcomes

Mutations in codons 12/13 of K-ras exon 2 are associated with reduced benefit from anti-epidermal growth factor receptor antibody treatment for metastatic colorectal cancer (CRC). Here, we evaluated the frequency of K-ras mutations and their relationship with clinicopathological features and treatment outcomes in Saudi Arabian patients with CRC. The genetic status of K-ras was determined in 300 patients diagnosed with CRC. Clinical information was collected retrospectively. K-ras was wild-type in 58% and mutated in 42% of the tumors. Most mutations were at codon 12 (89%) and were associated with metastasis [odds ratio (OR) = 1.38 (95%CI = 1.14-1.67] and occurrence of >40 µg/L carcinoembryonic antigen (CEA) [OR = 1.33 (1.1-1.74)] during diagnosis. Patients in stages I-III of the disease with wild-type K-ras tumors had a median relapse free survival (RFS) of 29 months in contrast to 22 months for those with the mutated K-ras tumor (P = 0.0357). In multivariate analysis, only the stage of the disease significantly predicted RFS (P = 0.001). Patients in stage IV of CRC with the wild-type K-ras tumor did not reach the median overall survival (OS), whereas patients with the mutated K-ras tumor survived for 23.5 months (P = 0.044). CEA level >40 µg/L (P = 0.004) and status of K-ras (P = 0.044) were independent predictors of OS. This is the largest study investigating K-ras mutations in patients with CRC in the Middle East. Mutations were associated with advanced stage of CRC, higher serum CEA, shorter RFS and OS.

Lapatinib-based therapy for women with advanced/metastatic HER2 positive breast cancer

BACKGROUND

Lapatinib alone or in combination with other agents, mostly capecitabine is used for patients with advanced/metastatic HER2 positive breast cancer (HER2(+)BC) after progression on trastuzumab based therapy. Here we report our experience with lapatinib based therapy in this setting.

MATERIAL AND METHODS

67 consecutive patients received lapatinib based therapy. 58 (86.6%) received lapatinib + capecitabine (LC), 7 (10.4%) with other agents and 2 (3.0%) as single agent lapatinib. Data was collected from patients' records retrospectively.

RESULTS

Objective response to lapatinib based therapy in 64 evaluable patients was 64.0% in all patients and 64.0% in patients who received LC. Median progression free survival and overall survival were 10 and 27 months in all patients and 10 and 17 months in patients who received LC, respectively. 16 (24.0%) patients had dose delay > 1 week and/or dose reduction.

CONCLUSION

Lapatinib based therapy is an effective treatment for women with advanced/metastatic HER2(+)BC after prior exposure to trastuzumab. It yields meaningful response rates, progression free and overall survival. Some patients require dose adjustments.

Optimization of the structure-switching aptamer-based fluorescence polarization assay for the sensitive tyrosinamide sensing

In this paper, a structure-switching aptamer assay based on a fluorescence polarization (FP) signal transduction approach and dedicated to the L-tyrosinamide sensing was described and optimized. A fluorescently labelled complementary strand (CS) of the aptamer central region was used as a probe. The effects of critical parameters such as buffer composition and pH, temperature, aptamer:CS stoichiometry, nature of the dye (Fluorescein (F) or Texas Red (TR)) and length of the CS (15-, 12-, 9- and 6-mer) on the assay analytical performances were evaluated. Under optimized experimental conditions (10 mM Tris-HCl, 5 mM MgCl(2) and 25 mM NaCl, pH 7.5 temperature of 22°C and stoichiometry 1:1), the results showed that, for a 12-mer CS, the F dye moderately increased the method sensitivity in comparison to the TR label. The F labelled 9-mer CS, however, did not allow the hybrid formation with the functional nucleic acid, thus emphasizing the importance of the nature of the fluorophore. In contrast, the same 9-mer CS labelled with the TR dye was able to effectively associate with the aptamer and was easily displaced upon target binding as demonstrated by a significant improvement of the sensitivity and a detection limit of 250 nM, comparable to those reported with direct aptasensing methods. The present study demonstrates that not only the CS length but also the nature of the dye played a preponderant role in the performance of the structure-switching aptamer assay, highlighting the importance of interdependently controlling these two factors for an optimal FP-based sensing platform.

DNA relatedness, karyotyping and gene probing of Candida tropicalis, Candida albicans and its synonyms Candida stellatoidea and Candida claussenii

Isolates of Candida albicans with varied phenotypes, including sucrose-negative variants (C. stellatoidea, serotypes A and B) and avirulent germ tube-negative forms (C. claussenii) showed significant (greater than 90%) DNA relatedness to classical C. albicans, but insignificant relatedness to C. tropicalis and sucrose-negative C. tropicalis. A transverse alternating-field gel electrophoresis procedure (TAFE) showed discrete karyotype patterns among the phenotypic variants of C. albicans including the sucrose-negative C. stellatoidea. The number of chromosome-sized DNA bands for C. tropicalis (7 bands) were within the range of bands observed for C. albicans (5 to 10 bands). The general DNA-migration pattern for C. albicans appeared distinct from that of C. tropicalis. An aspartyl proteinase (PrA) gene probe from C. albicans hybridized with chromosomal DNA from C. albicans, C. claussenii and C. stellatoidea but not with that from C. tropicalis.

Electrophoretic karyotyping of typical and atypical Candida albicans

Electrophoretic karyotypes of atypical isolates of Candida albicans, e.g., strains that were germ tube negative, failed to express proteinase activity, demonstrated low virulence for mice, formed hyperchlamydoconidia, produced hyperhyphae, or were sucrose negative (including the type strain of Candida stellatoidea), were compared with those of typical C. albicans. Karyotypes of whole-cell DNA of classical C. albicans examined with transverse alternating-field electrophoresis under specific conditions were composed of seven DNA bands with a specific migration pattern. Certain atypical strains and representatives of the three serotypes of C. stellatoidea produced discrete karyotypes with 5 to 10 bands. All isolates demonstrated a significant degree of DNA relatedness, suggesting their conspecificity. Densitometric tracings of DNA bands provided an objective and standardized method for comparing bands within the gels.