Browsing by Author "Lopez, J.M."

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    Bone turnover in lactating teenagers: Assessment at the end of pregnancy, during and after the breast feeding period
    (2000) Cattani, A.; Zubarew, T.; Maddaleno, M.; Mosso, L.; Lopez, J.M.
    Background: There is paucity of information about bone metabolism during pregnancy or breast feeding in teenagers. Aim: To study bone turnover at the end of pregnancy and during breast feeding in teenagers and correlate it with environmental, hormonal or nutritional variables. Subjects and methods: Thirty teenagers during their breast feeding period after a first pregnancy and 30 nulliparous girls matched for age, age of menarche and body mass index were assessed three weeks after delivery (period 1), at six months of breast feeding (period 2) and one year after the lactating period (period 3). Calcium intake and plasma calcium, phosphorus, alkaline phosphatases, parathormone, estradiol and prolactin were measured. Calcium, creatinine and hydroxypyroline were also measured in a morning urine samples. Results: Lactating and control girls were aged 16.3+/-0.8 and 16.1+/-0.7 years old respectively. Calcium intake in lactating and control girls was 798+/-421 and 640+/-346 g/day respectively in period 1, 612+/-352 and 592+/-309 mg/day in period 2 and 495+/-180 and 456+/-157 g/day in period 3. During periods 1 and 2, lactating girls had higher alkaline phosphatases (161+/-37 compared to 119+/-28 U/l and 149+/-37 compared to 106+/-23 U/l), parathormone (4.3+/-2.6 compared to 2/8+/-0.8 ng/dl and 3.6+/-1.6 compared to 3.0+/-0.9 ng/dl) and urinary hydroxyproline (95+/-16 compared to 63+/-15 mg/g creatinine and 84+/-19 compared to 59+/-15 mg/g creatinine). No differences were observed in period 3. No correlation between bone turnover variables, body mass index or hormonal parameters, was observed. Conclusions: In teenagers, there is an increase in bone turnover at the end of pregnancy, that persists during the lactating period. These changes are not relaxed to nutritional or hormonal variables.
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    Hipertiroxinemia con eutiroidismo clínico: análisis a propósito de un caso
    (1999) Lopez, J.M.; Mosso, L.; Campino, C.
    The association of hyperthyroxinemia and euthyroidism is frequent and characterized by high plasma thyroxin concentrations, normal TSH values and absence of clinical signs of hyperthyroidism. We report an asymptomatic 28 years old male presenting with a serum total plasma thyroxin of 18.5 mu g.gl (N 6.1-12.5), a free thyroxin of 2.9 ng/dl (N 0.8-1.4) a TSH of 3.4 mu IU/ml (N 0.5-5), and a triiodothyronine of 128 ng/dl (N 80-180). Laboratory assessment did not find high thyroxin binding globulin, albumin or prealbumin concentrations or antithyroxin antibodies. The thyroxin binding capacity of albumin was elevated to 58.2 mu g/dl (N 11.5-34.1). TSH responded normally to TRH stimulus and was suppressed with exogenous triiodothyronine, which caused an hyperthyroid syndrome. We concluded that this patient had a familial dysalbuminemia.