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This study suggests the employment of accumulated sediments in the reservoir of Tucuruí (Pará /Brazil) to remineralize the surrounding degraded soils. The approach was based on the principles of stonemeal technology. It suggests that the soil can be rejuvenated by crushed rocks rich in macro and micronutrients. Removal of the sediments for agricultural use will bring benefits to family farmers and increase the life cycle of the reservoir and, therefore, energy generation. Geochemical data on retained sediments, soils and rocks in the area of influence of the reservoir were evaluated regarding nutrient transport mechanisms and soil-fertility potential. Results show that sediments from the reservoir contain nutrients levels at least one order of magnitude greater than average Amazon region soils. Our data on soil use and occupation in the region show the degradation areas which could be recovered by stonemeal techniques. Thence, an Agroforestry System was installed, with 12 plots where different mixtures of sediments removed from the reservoir were used, along with crushed rock with or without the addition of NPK and manure. The experiments showed that maximum crop yield and plant growth were attained in the plots where a mixture of sediments, crushed rocks and manure were added.

Objective: To screen and subsequently sequence the TPO gene for mutations in patients with congenital goitre, hypothyroidism and evidence for an organification defect (positive perchlorate discharge test)., Patients: We have studied seven hypothyroid and congenitally goitrous patients from three unrelated families., Design and Measurements: We have measured serum thyroid hormone levels, 131I uptake, serum TSH and serum Tg concentrations. Denaturing gradient gel electrophoresis (DGGE) of PCR amplified genomic DNA was used to screen for mutations in the TPO gene., Results: DGGE identified the presence of two frameshift mutations: a GGCC duplication in exon 8 (homozygous in one family and heterozygous in the other family) and a heterozygous insertion of a single nucleotide (C) at position 2505-2511 in exon 14. In addition, we have detected an alteration in exon 11, not yet described in the literature, derived from a single nucleotide substitution of a C to G at position 2008, altering the well-conserved amino acid domain among the peroxidases superfamily. This mutation in exon 11 was present in two families that showed heterozygous mutation for exon 8 or for exon 14., Conclusions: These results could support the hypothesis for a putative compound heterozygosity pattern in the affected patients. The altered phenotype (goitre and hypothyroidism since birth) seems justifiable in view of the possible inactivating character of this novel mutation in exon 11.

Two unrelated families (CA and NA) in which an iodide organification defect (lOD) was present in two siblings of each family were studied. These patients had congenital goiters with hypothyroidism and a positive perchlorate discharge test. Examination of the thyroid tissue revealed no thyroid peroxidase (TPO) activity. Histologic findings were consistent with a microfollicular pattern of hyperplasia. Moderate cellular atypia was present, characterized by nuclear pleomorphism and hyperchromatism. Full length thyroglobulin was purified by gel filtration, but was not iodinated. Immunohistochemical studies using a polyclonal anti-human thyroid peroxidase (hTPO) antibody confirmed the presence of immunoreactive TPO protein in the thyroid tissues. Samples of normal and affected individuals were studied with respect to the presence of various fragments using TPO probes of varying sizes. The two affected siblings from family CA were homozygous for fragments 3.9, 4.6, and 7.0 kb (8g111) and 2.3 and 2.9 kb (Ta ql), whereas the parents were heterozygous. In the other family (NA), the Bg/ll digestion and TPO-31 hybridization revealed an interesting and informative polymorphism. The parents showed two different polymorphic patterns: the father had a 5.0/4.6 kb pattern and the mother a 4.7/4.5 kb pattern. However, the two affected siblings showed the same heterozygotic allelic pattern at 4.5/4.6 kb. The restriction fragment length polymorphism detected in these two families suggests an association between the TPO gene and an lOD. Results suggest that in these dyshormonogenetic tissues an altered TPO protein molecule is being synthesized, without detectable in vitro activity, but visible by immunostaining techniques in the goitrous tissue. Mutations in the TPC gene sequence are most likely associated with these changes.

Thyroid peroxidase (TPO) iodide and guaiacol oxidation activities were evaluated in eight dyshormonogenetic goiters. Two of these had a defective thyroglobulin; the TPO iodide oxidation (431 and 316 U/g ptn) and iodination (31 and 8.6 nmol I/mg ptn) activities were within the normal ranges. The goiters from two siblings with positive perchlorate iodide discharge tests also had normal TPO iodide oxidation (602 and 299 U/g ptn) and iodination activities (44 and 11 nmol I/mg ptn). No TPO iodide oxidation activity was found in the goiters from the other four patients with positive perchlorate iodide discharge tests, and TPO iodide oxidation inhibitory activities were detected in both their TPO and thyroglobulin preparations. Three of them had some TPO guaiacol oxidation activity and did not inhibit normal guaiacol oxidation. The TPO preparation immunoblot of these three goiters showed a faintly visible band of normal 100 kDa TPO. However, in the other patient no guaiacol oxidation activity was detected, and only two bands of low-molecular-weight TPO (72 and 43 kDa) were found, again showing that iodine organification defects in dyshormonogenetic goiters can be due to either qualitative or quantitative TPO defects. The TPO inhibition diminished when iodide was increased in the assay, but was not altered by increasing cofactor (H2O2). Our results, so far, suggest that the TPO-inhibitory substance may interact reversibly with a specific iodide site on the enzyme or with the oxidized form of iodide, and/or could bind free iodide, making it unavailable for enzymatic oxidation.