Measurement of plasma and intracellular S-adenosylmethionine and S-adenosylhomocysteine utilizing coulometric electrochemical detection: alterations with plasma homocysteine and pyridoxal 5'-phosphate concentrations

BACKGROUND: The relative changes in plasma and intracellular concentrations of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) may be important predictors of cellular methylation potential and metabolic alterations associated with specific genetic polymorphisms and/or nutritional deficiencies. Because these metabolites are present in nanomolar concentrations in plasma, methods of detection generally require time-consuming precolumn processing or metabolite derivatization. METHODS: We used HPLC with coulometric electrochemical detection for the simultaneous measurement of SAM and SAH in 200 microL of plasma, 10(6) lymphocytes, or 10 mg of tissue. Filtered trichloroacetic acid extracts were injected directly into the HPLC system without additional processing and were eluted isocratically. RESULTS: The limits of detection were 200 fmol/L for SAM and 40 fmol/L SAH. In plasma extracts, the interassay CV was 3.4-5.5% and the intraassay CV was 2.8-5.6%. The analytical recoveries were 96.8% and 97.3% for SAM and SAH, respectively. In a cohort of healthy adult women with mean total homocysteine concentrations of 7.3 micromol/L, the mean plasma value was 156 nmol/L for SAM and 20 nmol/L for SAH. In women with increased homocysteine concentrations (mean, 12.1 micromol/L), plasma SAH, but not SAM, was increased (P <0.001), and plasma pyridoxal 5'-phosphate concentrations were reduced (P <0.001). Plasma SAM/SAH ratios were inversely correlated with homocysteine concentrations (r = 0.73; P <0.01), and the SAM/SAH ratio in plasma was directly correlated with the intracellular SAM/SAH ratio in lymphocytes (r = 0.70; P <0.01). CONCLUSIONS: Increased homocysteine in serum is associated with an increase in SAH and a decrease in the SAM/SAH ratio that could negatively affect cellular methylation potential. Accurate and sensitive detection of these essential metabolites in plasma and in specific tissues should provide new insights into the regulation of one-carbon metabolism under different nutritional and pathologic conditions.     

Ectophosphatase activity in Candida albicans influences fungal adhesion: study between HIV‐positive and HIV‐negative isolates

Oral Diseases (2010) 16 , 431–438 Objective: This study describes the expression of acidic ectophosphatase activity on twenty isolates of C. albicans from oral cavities of HIV‐infected children (HIV+) and compares them with fifteen isolates from HIV‐negative children (HIV?), as well as the fungal adhesion to epithelial cells and medical records. Methods: The activities were measured in intact cells grown in BHI medium for 48 h at 37°C. Phosphatase activity was assayed at pH 5.5 using 4‐methylumbelliferyl phosphate. Yeast adhesion was measured using the MA 104 epithelial cell line. Results: Mean values of ectophosphatase activity were 610.27 ± 166.36 and 241.25 ± 78.96 picomoles 4‐methylumbelliferone/h/10⁷ cells for HIV+ and HIV? group, respectively (P = 0.049). No correlation between C. albicans enzyme activity from HIV children with viral load and CD4 percentual was observed. Yeasts with high enzyme activity, isolated from HIV+ children showed greater adherence than yeasts with basal levels of ectophosphatases from HIV? (Spearman correlation, r = 0.8). Surface phosphatase activity was apparently involved in the adhesion to host cells, as the enhanced attachment of C. albicans to host epithelial cells was reversed by pretreatment of yeast with sodium orthovanadate (1 mM), an acid phosphatase inhibitor. Conclusion: These results show that C. albicans from HIV+ has an ectophosphatase activity significantly higher than the other isolates. Yeasts expressing higher levels of surface phosphatase activity showed greater adhesion to epithelial cells. So, the activity of acidic surface phosphatases on these cells may contribute to the early mechanisms required for disease establishment.     

Orthodox versus unorthodox care: A qualitative study on where rural women seek healthcare during pregnancy and childbirth in Southwest,Nigeria

Introduction

Utilization of orthodox health facilities for maternal health services is determined by factors operating at the individual, household, community and state level. The prevalence of small family norm is one of the identified variables operating within the community which influences the decision of where to access care (orthodox/traditional). The objective of the study was to determine the use of orthodox versus unorthodox maternity healthcare and determinants among rural women in southwest Nigeria.

Methods

A qualitative study was done and involved three focus group discussions. A semi-structured interview guide was used to collect information from women of reproductive age group within a rural Local Government Area in Lagos state.

Results

Most of the women access some form of healthcare during pregnancy, orthodox, unorthodox or both. Those who patronize both services concurrently do so to benefit from the two as each has some unique features such as herbal concoctions for traditional, ultrasound and immunization of babies for orthodox. Traditional belief exerts a strong influence on decision of where to access maternal healthcare services. Actual place of delivery is determined by individual and household factors including financial resources.

Conclusion

Rural women utilize one or both orthodox and unorthodox maternal health services for different reasons. Ward Development Committees should be strengthened so as to reach the communities, educate and convince women to dispel myths which limit their use of orthodox care. Training and monitoring of Traditional Birth Attendants (TBAs) are vital to eliminate harmful practices. We also recommend improved financial access to orthodox healthcare.