Assessing the severity of the small inframe deletion mutation in the α-subunit of β-hexosaminidase A found in the Turkish population by reproducing it in the more stable β-subunit

GM(2) gangliosidoses are a group of panethnic lysosomal storage diseases in which GM(2) ganglioside accumulates in the lysosome due to a defect in one of three genes, two of which encode the alpha- or beta-subunits of beta- N -acetylhexosaminidase (Hex) A. A small inframe deletion mutation in the catalytic domain of the alpha-subunit of Hex has been found in five Turkish patients with infantile Tay-Sachs disease. To date it has not been detected in other populations and is the only mutation to be found in exon 10. It results in detectable levels of inactive alpha-protein in its precursor form. Because the alpha- and beta-subunits share 60% sequence identity, the Hex A and Hex B genes are believed to have arisen from a common ancestral gene. Thus the subunits must share very similar three-dimensional structures with conserved functional domains. Hex B, the beta-subunit homodimer is more stable than the heterodimeric Hex A, and much more stable than Hex S, the alpha homodimer. Thus, mutations that completely destabilize the alpha-subunit can often be partially rescued if expressed in the aligned positions in the beta-subunit. To better understand the severity of the Turkish HEXA mutation, we reproduced the 12 bp deletion mutation (1267-1278) in the beta-subunit cDNA. Western blot analysis of permanently transfected CHO cells expressing the mutant detected only the pro-form of the beta-subunit coupled with a total lack of detectable Hex B activity. These data indicate that the deletion of the four amino acids severely affects the folding of even the more stable beta-subunit, causing its retention in the endoplasmic reticulum and ultimate degradation.     

Effects of hormone replacement therapy on plasma homocysteine and C-reactive protein levels.

In order to investigate the effect of hormone replacement therapy (HRT) on plasma homocysteine and C-reactive protein (CRP) levels 46 healthy postmenopausal women were prospectively enrolled. HRT, which was either 0.625 mg/day conjugated equine estrogen (CEE) plus 2.5 mg/day medroxyprogesterone acetate (MPA) or 0.625 mg/day CEE alone were administered. After 6 months, estrogen alone significantly increased serum CRP concentrations (p = 0.039), however, estrogen plus progesterone therapy did not significantly alter serum CRP levels. Both regimens significantly decreased plasma homocysteine levels (CEE group p = 0.034, CEE+MPA group p = 0.007). It was concluded that the reduction in plasma homocysteine levels with both regimens might contribute to the cardiovascular benefit of HRT and the CRP raising effect of estrogen might be partially prevented by the addition of progesterone.     

Classification of reasons for rejection of biological specimens based on pre-preanalytical processes to identify quality indicators at a university hospital clinical laboratory in Turkey

Objectives

Specific types of error should be identified and corrected in each laboratory to ensure quality results. The objectives of this study were:

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to identify and classify the causes of biological specimen rejections,

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to determine the specimen rejection rates (SRRs) in terms of pre-preanalytical errors and with respect to collection areas, and

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to identify an appropriate quality indicator (QI) for the preanalytical phase in a university hospital clinical laboratory.

Design and methods

Data on rejected biological specimens in the laboratory information system from January 2013 to January 2014 were analyzed. SSRs according to the type of pre-preanalytical error and collection area were determined.

Results

In total, 971,780 biological specimens were received during the period and 26,070 (2.7%) specimens were rejected based on our laboratory rejection criteria. The most frequent reason for the rejection was the clotted specimen (55.8% of total rejections), followed by inadequate volume (29.3% of total rejections). Most of the clotted specimens were received from adult hospital inpatient services (54.3%), followed by pediatric hospital inpatient services (26.8%). High rates of inadequate volume were also observed in samples originating from adult and pediatric hospital inpatient services, especially in the premature, neonatal, intensive care, and oncology units.

Conclusions

The SSR of clotted specimens was selected as the QI for the preanalytical phase in our laboratory. The selected QI will help to define the effects of our specific interventions and corrective actions, and thus allow monitoring of quality improvement in our hospitals.     

Extent of coronary atherosclerosis and homocysteine affect endothelial markers

The aim of the study was to evaluate the effects of the presence, extent, and clinical stability of coronary artery disease on endothelial function parameters, C-reactive protein and homocysteine levels. Fifty-eight patients with angiographically documented coronary artery disease and 25 patients with normal coronary arteries were evaluated for risk factors, plasma homocysteine, C-reactive protein, and soluble adhesion molecule levels. Vascular cell adhesion molecule-1 and sE-selectin were significantly higher in the group with coronary artery disease than in healthy subjects (p = 0.005 and p = 0.031, respectively). Patients with unstable angina had significantly higher C-reactive protein (p < 0.001), troponin I (p < 0.01), and leukocyte counts (p < 0.05) than those with stable angina. sE-selectin levels were correlated with the extent of coronary atherosclerosis (r = 0.444, p < 0.05), and plasma homocysteine levels were associated with vascular cell adhesion molecule-1 (r = 0.479, p < 0.05) in unstable cases. These results suggest that vascular cell adhesion molecule-1 and sE-selectin are useful for determining the presence of coronary atherosclerosis, whereas C-reactive protein, troponin 1, and leukocyte count are predictors of clinical stability.