Folate levels and N(5),N(10)-methylenetetrahydrofolate reductase genotype (MTHFR) in mothers of offspring with neural tube defects: a case-control study.

BACKGROUND: Neural tube defects (NTDs) have been associated with biochemical factors involved in the conversion of homocysteine to methionine as folate deficiency and the mutation 677T in the N(5),N(10)-methylenetetrahydrofolate reductase gene (MTHFR). METHODS: A case-control study was performed to detect this mutation in 38 unrelated women with NTD deceased products and 31 mothers without antecedents of NTD offspring. All products were born in Nuevo León (northeastern Mexico) during 1997. Erythrocyte and plasmatic folate levels and the genotype of the 677 polymorphism at the MTHFR locus were analyzed in both groups. RESULTS: Although no significant differences were found in mean blood folate levels, the percentage of women in the case group with erythrocyte folate levels <160 ng/mL was significantly higher than in the control group (75 vs. 51.2%, p <0.05). The proportion of women with plasma folate levels <3.5 ng/mL was higher in the case group (16.2 vs. 0%, p <0.01). Genotype analysis demonstrated a significantly higher proportion of 677T homozygous mothers with NTD products (39.6 vs. 9.1%, p <0.05). Allele frequencies for the 677T mutation were 0.55 and 0.36 for cases and controls, respectively. The odds ratio (OR) for having a NTD product was 6.1 (95%, CI 1.56-23.6) for homozygous 677T mothers vs. homozygous 677C and heterozygous mothers. Significantly low levels of erythrocyte folate were found in the 677C homozygous case group and in plasma folate in the 677C/677T heterozygous case mothers. CONCLUSIONS: Our study suggests that folate deficiency and MTHFR unfavorable genotype in mothers are important risk factors for severe NTD phenotype in our population.

[Impact of weekly administration of folic acid on folic acid blood levels]. / Efecto de la administración semanal de ácido fólico sobre los valores sanguíneos.

OBJECTIVE: To evaluate the effect of weekly administration of 5 mg. folic acid (FA) intake on folic acid blood levels. MATERIAL AND METHODS: This concurrent comparative study was conducted in 1998, in urban and rural areas of Nuevo Leon State, Mexico. The study population consisted of 74 women who delivered a child during 1997, 39 of whom had a child with a neural tube defect. Women were given 5 mg. of folic acid, weekly for 3 months. Blood levels of folic acid were determined by radioimmunoassay (RIA) at baseline, and a week after taking the last folic acid dose. Data are presented as means and standard deviations. RESULTS: Ninety per cent of the women had significantly increased folic acid intraerythrocytary blood levels. Red cell folate increased from 150.49 +/- 31.17 ng/ml to 184.21 +/- 35.53 ng/ml (p < 0.005). Plasma folate increased from 5.93 +/- 1.98 ng/ml a 7.03 +/- 2.5 ng/ml (p < 0.05). Eighty-two per cent of women reached intracellular levels above 160 ng/ml. CONCLUSIONS: The weekly administration of folic acid is a simple and efficient method that could be used to supplement this vitamin to low-income populations. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

[Folic acid levels, homocysteine and polymorphism of methylenetetrahydrofolate reductase enzyme (MTHFR) in patients with pre-eclampsia and eclampsia]. / Niveles de ácido fólico, homocisteína y polimorfismo de la enzima metilentetrahidrofolatorreductasa (MTHFR) en pacientes con preeclampsia severa y eclampsia.

UNLABELLED: Preeclampsia and eclampsia are the primary causes of maternal mortality. In the state of Nuevo León, from 1990 to 1998, these conditions represented 44.1% of maternal deaths. The presence of thrombogenic substances (homocysteine, C protein, and anticardiolipin antibodies) in the mother's blood has been related to this problem. The C677T polymorphism of the enzyme methylene tetrahydrofolate reductase (MTHFR) favors the increase of homocysteine levels, while folic acid (FA) supplementation decreases its levels. OBJECTIVE: To establish the role of FA in the physiopathology of preeclampsia in our environment. KIND OF STUDY: Longitudinal, prospective and comparative. CASES: Women with severe preeclampsia and/or eclampsia (n-13). CONTROLS: Women in the third trimester of a normal pregnancy (n + 15). 20 mL Blood samples were taken during the first 24 hours of puerperium, and their AF, homocysteine and MTHFR polymorphism were measured. The t Student test and the Exact Fisher test were used to compare between both groups. RESULTS: The values obtained for homocysteine were (x + SD): CASES: 9.85 micromoles/L + 2.88, and controls: 7.61 micromoles/L + 1.32 (p < 0.04). The frequency (%) of the genetic polymorphism for MTHFR was: positive homozygotes (T/T): 38.46 vs. 20, heterozygotes (C/T): 38.46 vs. 26.6, negative homozygotes (C/C): 23 vs 53, for cases and controls, respectively. CONCLUSIONS: According to our study, the frequency of the homozygote state (T/T) of MTHFR and increased blood levels of homocysteine is greater in women suffering from preeclampsia.

In vitro selective toxicity of toxin T-514 from Karwinskia humboldtiana (buckthorn) plant on various human tumor cell lines.

Toxin T-514 is a dimeric anthracenone isolated from the Karwinskia humboldtiana (buckthorn) plant. Its potential anti-neoplastic effect was evaluated in vitro and the results obtained were compared with the effect of other known anti-cancer agents. Normal and malignant continuous cell lines were tested. After a 72-h exposure, neoplastic cells derived from hepatic, pulmonary and colonic tissues were more sensitive to toxin T-514 than normal cells from the corresponding organ. Hepatoma cells and colon adenocarcinoma CT50 values were < 10 micrograms/ml. Lung adenocarcinoma, undifferentiated bronchogenic cancer cells and small cell carcinoma CT50 values were < 20 micrograms/ml. All benign cell CT50 levels tested were > 113 micrograms/ml. This in vitro selective toxicity found with toxin T-514 was also seen with 5-fluororacil and mitomycin for colon adenocarcinoma and with epidoxorubicin for undifferentiated bronchogenic cancer cells.

Effect of toxins 544 and 514 from Karwinskia humboldtiana (buckthorn) plant upon fetal development of the mouse.

The teratogenic effect of toxins 544 and 514 from K. humboldtiana upon the mouse embryo was evaluated. One half of the LD50 dose for the mouse was administered at day 8 of gestation. At the end of pregnancy, reproduction and fetal data were recorded. Dams treated with toxin 544, but not with toxin 514, showed a higher incidence of reabsorptions, malformations, as well as lower fetal length compared to the control group.

Effects of toxin T-544 from the Karwinskia humboldtiana (buckthorn) plant upon mouse embryos explanted at 11 days.

Eleven-day mouse embryos were exposed to the K. humboldtiana toxin T-544 for 24 hr. At the end of the culture period, embryos were examined grossly for malformations and biochemically for altered protein levels. There was a significant difference in malformations in those embryos exposed to 0.05 and 0.2 microgram/ml of toxin compared with controls. Embryo protein content was significantly lower in those embryos exposed to 0.1 microgram/ml of T-544 compared with control group.

Effects of hormones on postimplantation mouse embryos in vitro. II. Progesterone and estrogen.

Mouse embryos at day 9 of development were cultured for 24 to 42 h in 50% fetal calf serum and 50% Waymouth's medium containing 0.5 micrograms/ml insulin supplemented with various amounts of progesterone and estradiol-17-beta. Unmodified medium contained approximately 0.2% of the normal maternal blood levels for that stage of pregnancy. The addition of 1 X 10(-7)M progesterone to the medium brought the level near that of the normal maternal circulating amount and appeared to be beneficial for in vitro development. After 24 h of cultivation there was a statistically significant increase in somite number, the number of embryos developing posterior limb buds, and protein accumulation over the control embryos. The addition of small amounts of estradiol-17 beta (1 X 10(-10)M) increased the protein accumulation of the embryo over that of progesterone alone and seems to enhance the beneficial effects of progesterone addition.

Cultivation of mouse embryos explanted at 11 days.

A method for cultivation of 11-day mouse embryos (plug day = day 0) is presented. Competence of the visceral yolk sac and serum dilutions were tested. Eleven day mouse embryos were cultivated for 24 hours with the visceral yolk sac either opened or left intact. Fetal calf serum (FCS) at 0%, 25%, and 50% dilutions balanced with Waymouth's medium was used as cultivation medium. Viability and growth of the embryos were evaluated by heart rate at 6 hours, and protein accumulation and differentiation at 24 hours. At 6 hours, best results were found in those embryos with the visceral yolk sac intact. Serum dilutions at this time were not important for viability. At 24 hours, only those embryos cultivated with the visceral yolk sac opened were alive. Significant increase in viability was obtained when a 50% dilution of FCS was used. There was a significant increase in protein accumulation for viable embryos at 24 hours.