Investigation of metal complexes with metallothionein in rat tissues by hyphenated techniques.

The potential of hyphenated techniques based on a combination of microbore reversed-phase (RP) HPLC or capillary zone electrophoresis (CZE) with inductively coupled plasma (ICP) or electrospray (ES) mass spectrometry (MS) was demonstrated for the characterization of metal complexes with metallothionein in rat liver and kidney. The mixture of MT complexes was isolated from the tissues by size-exclusion LC and further characterized in neutral pH conditions (pH 6.8-7.2) by RP-HPLC or CZE. The metal stoichiometry and the molar mass of the eluted complexes was measured by ICP-MS and ES-MS, respectively. An additional dimension to the analysis was achieved by post-column acidification of the chromatographic eluent that allowed the determination of the molecular weight of the demetallated complexes with 10-fold higher sensitivity. The approach allowed the detection of two major metallothionein (MT) isoforms (MT-1 and MT-2) in liver and one MT isoform in kidney. The actual number of peaks in chromatograms and electropherograms was bigger because of the formation of mixed Cd-Cu complexes of the same MT isoform that showed different hydrophobicities.

Relative hypoadiponectinemia, insulin resistance, and increased visceral fat in euthyroid prepubertal girls with low-normal serum free thyroxine.

A lower activity of the thyroid axis within the clinical reference range is related to a dysmetabolic phenotype in adult populations. We posited that such an association is already present as early as in prepubertal childhood. Serum thyroid stimulating hormone (TSH) and free T4, body fat (bioelectric impedance), insulin resistance (homeostasis model assessment of insulin resistance (HOMA(IR))), total and high molecular weight (HMW)-adiponectin and serum lipids were assessed in 234 euthyroid prepubertal children (113 boys and 121 girls) attending primary care clinics. Visceral fat (abdominal ultrasound) was measured in a subset of these subjects (n = 147; 74 boys and 73 girls). Explants of visceral adipose tissue from an additional six prepubertal children (three boys and three girls) were used to study the regulation of total and HMW-adiponectin by thyroid hormone. Serum free T4 was in girls independently associated with HMW-adiponectin, HOMA(IR) and visceral fat, so that circulating HMW-adiponectin decreased by 30% (ß = 0.305 P < 0.005, R(2) = 0.13) and HOMA(IR) and visceral fat increased, respectively, by 90% (ß = -0.255 P < 0.01, R(2) = 0.05) and 30% (ß = -0.369, P < 0.005, R(2) = 0.12) from the highest to the lowest tertile of serum free T4. Nonsignificant differences in these parameters were found in boys. Treatment of visceral fat explants with thyroid hormone increased total and HMW-adiponectin by 70% and 53%, respectively, above control values (P < 0.01). In conclusion, a dysmetabolic phenotype, consisting of relative hypoadiponectinemia, insulin resistance and increased visceral fat, is associated with low-normal serum free thyroxine in euthyroid prepubertal girls. These associations may be partly explained by a positive regulation of HMW-adiponectin secretion by thyroid hormone.

Prenatal programming of renal function: the estimated glomerular filtration rate is influenced by size at birth in apparently healthy children.

Prenatal growth is known to affect glomerular function in adult life. It is unknown, however, whether this association is also present in children. In a cross-sectional study, we examined whether birth weight (BW) is associated with serum creatinine (measured by an improved Jaffe method) and GFR (estimated by the Haycock-Schwartz formula; eGFR) in 73 apparently healthy school-age children (35 boys and 38 girls; age 9.5 +/- 0.4 yr). All children were born after singleton term pregnancies (gestational age 39.6 +/- 0.2 wk) with normal BW (3.2 +/- 0.04 kg). A significant decrease in serum creatinine and increase in the eGFR was evident by tertiles of BW-SD score (SDS) (p = 0.001 and p < 0.0001). eGFR was correlated with BW-SDS (r = 0.45; p < 0.0001), so that each unit increase in BW-SDS was associated with an increase in eGFR of 10 (95% CI 5-14) ml/min per 1.73 m. In summary, estimates of glomerular function are in apparently healthy school-age children influenced by size at birth. These findings suggest early effects for the prenatal programming of renal function in humans.

Heritability of explosive power and anaerobic capacity in humans.

There is a disparity in the information about the heritability of the response of muscle anaerobic metabolism to exercise and the use of explosive power, as well as a lack of information concerning the genetic determinants of this form of work, as measured using different specific physical tests. We applied a battery of some of the commonly employed procedures (Ergojump, Wingate, maximal accumulated oxygen deficit, excess post-exercise oxygen consumption, and delta lactate concentration) to a group of 32 Caucasian male twins, 8 monozygotic and 8 dizygotic pairs, who had similar environmental backgrounds. Results were studied using a heritability index (HI). Zygosity was determined using the identity of erythrocyte antigens, protein and enzyme polymorphism and human leucocyte antigen serologic types between co-twins. Significant HI values (P< 0.05) were found in the following tests: maximal 5 s power (HI = 0.74) and total power in a 30 s interval (HI = 0.84) in the Wingate test, maximal lactate concentration (HI = 0.82) and delta lactate concentration (HI = 0.84) in the maximal progressive test, as well as in the 2nd (HI = 0.93) and in the 3rd min (HI = 0.92) of recovery after the deficit test. In this study, the most relevant findings were: firstly, significant HI values for many of the variables studied; secondly, the HI values of the parameters used to evaluate explosive power were higher than those of lactic acid capacity and thirdly, the HI of certain variables from different tests measuring, in theory, similar qualities, were different.