RESUMEN
OBJECTIVES: Most of the lipids of the skin surface come from sebaceous glands secretions, called sebum. Some of the sebum lipids are synthesized by sebaceous cells while some are reportedly derived from the plasma. Role of blood lipoproteins in sebum secretion rate and composition is unclear. To this end, excretion rate and composition of skin surface lipids of normo- and type IV hyperlipoproteinemic subjects were compared. DESIGN AND METHODS: Quantitative analysis of skin surface lipids was performed by three successive sampling on left, middle, and right zones of the forehead with a sebumeter. Skin surface lipid samples for the compositional analysis were collected from the forehead, extracted into n-hexane, and analyzed by high performance thin layer chromatography (HPTLC). HPTLC plates were scanned with a densitometer for the quantification of the lipids. RESULTS: Skin surface lipids from type IV hyperlipoproteinemic subjects contained higher proportion of wax ester + cholesterol ester compared with that from normolipoproteinemic subjects. However, skin surface lipid excretion rates of normo- and hyperlipoproteinemic subjects were found to be similar. CONCLUSIONS: Plasma lipid/lipoprotein concentration may be a determinant factor in sebum lipid composition.
Asunto(s)
Frente , Hiperlipoproteinemia Tipo IV/metabolismo , Lípidos/química , Sebo/química , Piel , Adulto , Colesterol/química , Cromatografía Líquida de Alta Presión , Humanos , Concentración de Iones de Hidrógeno , Metabolismo de los Lípidos , Lípidos/sangre , Masculino , Persona de Mediana Edad , Sebo/metabolismo , Escualeno/química , Triglicéridos/química , Agua , Ceras/químicaRESUMEN
Polychlorinated biphenyls (PCBs) are persistent environmental pollutants. Two PCB mixtures, Aroclors 1221 and 1254 have been suggested to have estrogenic and anti-estrogenic properties, respectively. We have examined whether these PCB mixtures modulate bone turnover and vertebral histology in intact and ovariectomized (ovx) rat models. Thirty-two adult female rats were divided into four groups subcutaneously receiving 4% DMSO (control), A1221 (10 mg/kg), A1254 (10 mg/kg) oestradiol (E2, 30 microg/kg). These compounds were injected to the animals for a period of 6 weeks at two daily intervals. In the second model, rats (n=32) were ovx and allowed to recover for a period of 3 weeks. Control group received vehicle (4% DMSO) alone. Remaining rats were divided into three groups and injected (s.c.) with A1221, A1254 and E2 for 5 weeks. Urine samples were collected prior to end of the experiments. Then, all animals were decapitated. Serum parathyroid hormone (PTH), calcitonin and osteocalcin levels were determined by immunoradiometric method. Serum concentrations of alkaline phosphatase (ALP), calcium and inorganic phosphate were determined by enzymatic-colorimetric method. Urinary deoxypyridinoline (DPD) was measured by ELISA. Lumbar vertebrae (L2) of all animals were dissected out and processed for light microscopy. Levels of urinary DPD were significantly lowered in E2 -treated intact rats (p<0.001). Ovx significantly increased urinary DPD excretion (p<0.01) compared to intact control values. Administration of A1221 and A1254 had no significant effects in intact rats, however, they significantly reduced (p<0.05) and increased (p<0.001) urinary DPD levels in ovx rats, respectively. Neither of the PCB mixtures significantly changed serum osteocalcin and ALP levels in intact or ovx rats (except A1221 increased ALP in intact model, p<0.01). Both PCB mixtures had differential effects on serum PTH, calcitonin, calcium and inorganic phosphate concentrations. Treatment with A1221 reversed the adverse effects of ovariectomy on L2 histology. However, A1254 produced necrotic areas in vertebral bone, and this effect was expanded in ovx animals. Our findings suggest that both Aroclor compounds interfere with bone turnover mechanisms, particularly in ovx rats.
Asunto(s)
Arocloros/farmacología , Huesos/metabolismo , Columna Vertebral/patología , Fosfatasa Alcalina/sangre , Aminoácidos/orina , Animales , Huesos/efectos de los fármacos , Calcitonina/sangre , Calcio/sangre , Estradiol/farmacología , Femenino , Osteocalcina/sangre , Ovariectomía , Hormona Paratiroidea/sangre , Fosfatos/sangre , Ratas , Ratas Wistar , Columna Vertebral/efectos de los fármacosRESUMEN
OBJECTIVE: The objectives of this study were to compare and make correlations between age and Doppler parameters of the interlobar arteries, including synchronously obtained plasma renin and aldosterone levels and to obtain new normative data regarding acceleration time in healthy children from neonates to 16 years. SUBJECTS AND METHODS: One hundred sixty-nine healthy children (72 girls and 97 boys) were classified into four groups: group 1 (< 1 year; n = 34), group 2 (range, 1-6 years; n = 48), group 3 (range, 6-12 years; n = 50), and group 4 (range, 12-16 years; n = 37). Blood samples from the renin and aldosterone were collected in the morning after bed rest and fasting. The resistive index (RI), pulsatility index (PI), and the acceleration time of the renal interlobar arteries with duplex Doppler sonography, including both kidney longitudinal lengths with grayscale sonography, were evaluated. One-way analysis of variance with the least significant difference post-hoc test and Pearson's correlation test were used to compare the differences between groups and to make correlations, respectively. An independent-sample t test was used to evaluate the differences between all parameters based on sex and to compare the left and right kidney longitudinal lengths in each group. RESULTS: The RI, PI, and acceleration time were statistically significant in between-group comparisons. Only in group 4 was acceleration time not statistically significant compared with groups 2 and 3. Plasma renin levels were significantly higher in group 1 compared with groups 2 (p < 0.03) and 4 (p < 0.0001); in group 2 compared with group 4 (p < 0.05); and in group 3 compared with group 4 (p < 0.01). The plasma aldosterone levels were significantly higher only in group 1 compared with groups 2 (p < 0.001), 3 (p < 0.008), and 4 (p < 0.0001). The RI correlated linearly with the PI, plasma renin levels, and aldosterone levels and correlated inversely with acceleration time. Age had a negative correlation with the RI, PI, plasma renin levels, and aldosterone levels and correlated positively with acceleration time. There were no statistically significant differences between all parameters based on sex and no significant difference found between the right and left kidney longitudinal lengths in each group. CONCLUSION: The RI in children up to 54 months old is higher than in adults. Therefore, the adult mean renal RI criterion of 0.70 should be applicable to children 54 months old and older. We showed that the age dependency of the RI was directly related to that of plasma renin and aldosterone levels in healthy children in whom Doppler parameters and blood analysis were evaluated synchronously.