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Biomedical subjects

E Terán

Publications and source records attributed to E Terán.

9 recordsLinked to original sources
PubMed2006

Lack of chemopreventive effects of ginger on colon carcinogenesis induced by 1,2-dimethylhydrazine in rats.

Ginger (Zingiber officinale Roscoe) has been proposed as a promising candidate for cancer prevention. Its modifying potential on the process of colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) was investigated in male Wistar rats using the aberrant crypt foci (ACF) assay. Five groups were studied: Groups 1-3 were given four s.c. injections of DMH (40 mg/kg b.w.) twice a week, during two weeks, whereas Groups 4 and 5 received similar injections of EDTA solution (DMH vehicle). After DMH-initiation, the animals were fed a ginger extract mixed in the basal diet at 0.5% (Group 2) and 1.0% (Groups 3 and 4) for 10 weeks. All rats were killed after 12 weeks and the colons were analyzed for ACF formation and crypt multiplicity. The rates of cell proliferation and apoptosis were also evaluated in epithelial colonic crypt cells. Dietary consumption of ginger at both dose levels did not induce any toxicity in the rats, but ginger meal at 1% decreased significantly serum cholesterol levels (p<0.038). Treatment with ginger did not suppress ACF formation or the number of crypts per ACF in the DMH-treated group. Dietary ginger did not significantly change the proliferative or apoptosis indexes of the colonic crypt cells induced by DMH. Thus, the present results did not confirm a chemopreventive activity of ginger on colon carcinogenesis as analyzed by the ACF bioassay and by the growth kinetics of the colonic mucosa.

1,2-Dimethylhydrazine↗
PubMed2002

Bone-mass peak in multiparity and reduced risk of bone-fractures in menopause.

OBJECTIVES: Pregnancy has been proposed as a risk factor for the development of osteoporosis; however, the results are controversial. Women in Colombia are multiparous, and therefore they represent an ideal population for the investigation of the effect of parity on osteoporosis. METHODS: The study included 1855 post-menopausal Hispanic women from Barranquilla, Colombia who were referred to our osteoporosis clinic for a routine evaluation of their bone mineral status. Bone mineral density (BMD, g/cm(2)) was measured using dual energy X-ray absorptiometry. Total body, femoral and lumbar areas were scanned. RESULTS: BMD of total body, hip and legs (P<0.0001), Ward's area (P<0.002) and intertrochanteric area (P<0.003) was high in women with at least one delivery in comparison with nulliparous women. Total mineral and calcium body contents were also high in women after second delivery. A history of fractures was found in 22.9% (n=425) of the study women. The relative risk for bone-fractures was high (O.R. 0.41; P<0.000002) in nulliparous women in comparison to multiparous women. In addition, osteopenia (O.R. 2.01; P=0.008) and osteoporosis (O.R. 3.99; P=0.0004) were most often present in nulliparous women in comparison to multiparous women. CONCLUSIONS: Pregnancies in this population appear to be a protective factor against development of osteoporosis. The increase in total mineral and calcium contents was related to the number of pregnancies, suggesting the existence of a bone mass peak during pregnancy.

Aged↗
PubMed1999

Improvement in functions of the central nervous system by estrogen replacement therapy might be related with an increased nitric oxide production.

Estrogen promotes neurons growth, prevents neuronal cell atrophy and regulates synaptic plasticity. Administration of estrogen protects neurons against oxidative stress, excitotoxins, and beta-amyloid-induced toxicity in cell culture. It has been shown that estrogen treatment reduces the serum monoamino oxidase levels and might regulate learning and memory. Nitric oxide (NO) is a retrograde messenger and long-term potentiation can be block using NO-synthase inhibitors or can be prevent with NO-scavengers. NO synthase is widespread in the central nervous system and acts as neurotransmitter/neuromodulator. The actions of serotonin, bradykinin, endothelin, acetylcholine and noradrenaline might be linked to NO formation. Estrogen induces activity of constitutive NO synthase and estrogen replacement therapy in postmenopausal women increases significantly circulating nitrite plus nitrate levels. The effect of estrogen on NO synthesis is rapid and is maintained with repeated administration. We demonstrated the effects of estrogen replacement therapy in Andean postmenopausal women were associated with a significantly increase in plasma levels of nitrite plus nitrate. Our hypothesis is that beneficial effect of estrogen replacement therapy on involutive depression in postmenopausal women is mediated by increase in NO production by central nervous system.

Brain↗
PubMed1997

Calcium supplementation and the risk of preeclampsia in Ecuadorian pregnant teenagers.

OBJECTIVE: To determine whether increased calcium intake (2 g/day) in pregnancy is effective in reducing the risk of preeclampsia in pregnant teenagers. METHODS: The present study was a prospective, randomized, double-blind, controlled clinical trial. Two hundred sixty teenaged pregnant girls attending the Hospital Gíneco-Obstétrico Isidro Ayora in Quito, Ecuador, were included. Selection criteria were age less than 17.5 years, nulliparity, first prenatal visit before 20 weeks' gestation, and residency in Quito (2800-m altitude). We used a table of random numbers to assign 125 girls to receive 2000 mg of elemental calcium daily, beginning at 20 weeks of gestation and continuing until delivery; 135 women in the control group received a placebo. Blood pressure (BP) was measured twice every 4 weeks until delivery and at 48 hours after delivery. The diagnosis of preeclampsia was defined as BP greater than 140/90 mmHg on at least two occasions more than 6 hours apart and proteinuria greater than 30 mg/dL (over one cross by dipstick on two occasions 4-24 hours apart). RESULTS: The average daily calcium intake in this population was approximately 51% of the Recommended Dietary Allowance. Calcium supplementation was associated with a significantly decreased risk of preeclampsia (risk reduction 12.35%; P < .001), with 3.2% (n = 4) developing preeclampsia in the treatment group versus 15.5% (n = 21) in the placebo group. Moreover, calcium supplementation led to a reduction in systolic BP of 9.1 mmHg and in diastolic BP of 6.0 mmHg. CONCLUSION: These results suggest that calcium supplementation during pregnancy in populations with low calcium intake is a safe, effective, and inexpensive preventive measure that significantly reduces the risk of preeclampsia.

Adolescent↗
PubMed1997

Serum level of Zn, Cu and Fe in healthy schoolchildren residing in Mérida, Venezuela.

Levels of Zn, Cu and Fe were measured in blood serum samples of 320 children: 160 boys and 160 girls randomly selected, ages between 7 and 14 years, all considered healthy and residing in the City of Merida, Venezuela. The metals were determined using flow injection analysis-flame atomic absorption spectrometry. There was a tendency for serum Zn (SZn) to increase with age. There was no significant difference in SZn levels between males and females in the different age groups. Serum copper (SCu) decreases significantly (p < 0.05) with age in male children, whereas it increases in female children. The concentration of serum iron (SFe) tends to be lower than that reported in the literature. However, the age groups studied showed no statistically significant sex and age-related differences. The results are compared with values previously reported for healthy children studied in other communities. The present study has shown that there is a complex interaction between SZn, SCu, SFe and age and sex of the children. On the other hand, our observations also suggest that more detailed studies of these metals should be done, and that the study should include metabolic balances and associations between SZn, SCu, SFe and anthropometric variables (height, weight, body mass index and skinfold thickness).

Adolescent↗
PubMed1995

Calcium supplementation prevents pregnancy-induced hypertension by increasing the production of vascular nitric oxide.

Pregnancy-induced hypertension (PIH) remains a common cause of maternal and fetal morbidity and mortality. During the past 7 years, some progress has been made in the prevention of PIH. Specifically, clinical studies have shown that supplementation with calcium can significantly reduce the frequency of PIH, specially in populations with a low calcium intake. We have suggested that, in such a population, calcium supplementation is a safe and effective measure for reducing the frequency of PIH. Thus, the purpose of this article is to advance a hypothesis about the mechanism by which calcium supplementation reduces the risk of PIH. We propose that dietary calcium supplementation reduces the frequency of PIH by maintaining the serum ionized calcium level which is crucial for the production of endothelial nitric oxide, the increased generation of which maintains the vasodilatation that is characteristic of normal pregnancy.

Calcium↗