Development of Enzyme Linked Immunosorbent Assay for Erythropoietin / 대한진단검사의학회지

BACKGROUND: The aim of our study was to optimize and establish erythropoietin (EPO) enzyme linked immunosorbent assay (ELISA) system. METHODS: We prepared several monoclonal and polyclonal antibodies specific to human-EPO. The best combinations of antibodies for coating and detecting antibodies were selected for the establishment of ELISA. We tested several methods such as a competitive EIA and a sandwich ELISA. RESULTS: The best sandwich ELISA was optimized compared to competitive EIA when purified polyclonal antibody (PoAb) was used as a coating antibody and biotinylated PoAb as a detecting antibody. This sandwich ELISA easily detected EPO when PoAb pairs were used compared to the ELISA using monoclonal antibody and PoAb. There were no significant differences between the effects of various blocking solutions on the performance of sandwich ELISA using biotinylated antibody. The ELISA system using PBST containing 3% BSA as a blocking solution can sensitively detect EPO (10 mU/mL) in a broad range of EPO concentrations (10-2,000 mU/mL) and there were cross-reactions with other cytokines). CONCLUSIONS: EPO can be easily determined by using biotinylated PoAb as a detecting antibody and another PoAb as a coating antibody.

Minimal Weight and Body Fat Percentage in Relation to the Onset of Menarche in Korean Females / 대한지역사회영양학회지

Menarche is a main indicator of sexual maturity which relates to a reproductive function. The onset of the menstrual cycle differs individually and is influenced by many variables such as socio-economic situation, race, genetics, climate, altitude, nutritional status, and physical growth. Among them physical growth has been known to be the most influencing factor, particularly when expressed as body fat designated by weight. This study intended to investigate the body composition of girls around the menarche period and to evaluate the minimal levels of weight and fat percentage needed for the onset of menarche. A total of 101 female subjects, aged 11 to 13 years, were recruited from the 5th and 6th grades of an elementary school, in Mokpo, Korea. The subjects were placed into one of two groups Pre-menarche and Post-menarche groups according to their experience with menarche. Thereafter, the subjects in the Post-group were placed into 4 subgroups based on the number of menstruations they experienced: Post-I (1 - 3 times), Post-II (4 - 6 times), Post-III (7 - 9 times), and Post-IV (> 10 times). The average age at the onset of menarche of the subjects in Post groups was 11.2 +/- 0.6 years. There were significant differences in the data of anthropometry and body composition between the Pre and Post groups, although the mean ages of both Pre and Post groups were the same. Weight, waist, hip and thigh girths, fat percentage, and lean body mass of the Post groups were significantly higher than those of the Pre group. Height was not significantly different between the groups. Weight was highly correlated with body fat mass (r = 0.92, p < 0.001), fat percentage (r = 0.85, p < 0.001), and body mass index (r = 0.91, p < 0.001). These results indicate that weight, compared with height, reflects body composition well and influences the onset of the menstrual cycle. It could also be suggested that the minimal weight and fat percentage needed for the onset of menarche in Korean females are 41 kg and 17% to 19%, respectively.

Iron Status of the Adolescent Females before and after Menarche

This study was performed to determine the iron status of the adolescent Korean girls before and after menarche. The 101 subjects aged 11-13 years who attending in an elementary school in Mokpo were recruited. They were divided into pre-menarche (A) group or post-menarche (B) group based on their menstruation status. The latter subjects were sub-divided into one of the four groups according to the times of their menstruation B-I(> or =3 times), B-II (4-6 times), B-III (7-9 times) or B-W (> or =10 times). In the total subjects, dietary iron intake, 11.3 mg/day, was below the Korean RDA for iron, the percentage of heme iron to total iron intake, 15%, and the bioavailability of dietary iron, 12.3%, seemed to be low. And their body iron storage, 140.8 mg, seemed to be insufficient. However, they tended to meet body's iron requirement in the cell level. Red blood cell number (RBC), hematocrit (Hct), and hemoglobin (Hb) level in the total subjects were 4.5 1012/I, 39.3%, and 13.0 g/dl, respectively. The subjects in B group had lower (p<0.05) RBC and Hct compared to those in A group and the prevalence of iron-deficiency anemia tended to be high. Serum iron, ferritin, and soluble transferrin receptor (sTfR) and sTfR:ferritin ratio were 86.7microgram/d, 17.6microgram/l, 3.58 mg/1, and 230, respectively. Those four indices were not significantly different among the groups. The results of this study imply that, although there a tendency to affect negatively iron status, menstrual blood loss in adolescent females does not deteriorate obviously their iron status during the relatively short period up to 1 you. However, it should be better to improve their iron status after starting menarche by increasing iron intake, especially heme-iron, and enhancing factors for iron absorption.