[Hypervitaminosis D in institutionalized elderly in Buenos Aires]. / Hipovitaminosis D en ancianos institucionalizados de Buenos Aires.

Several studies have shown that vitamin D (Vit. D) deficiency in elderly people enhances bone mass loss. Most of these studies have been carried out in areas of low solar irradiation. In order to establish Vit. D circulating levels in elderly people in our community (34 degrees S) and their relationship with bone metabolism, 34 men and 33 women were studied at the end of the summer. These subjects, all residents of nursing homes, had a mean age of 81.9 + 8.1 years (range 69-99). Calcemia, parathyroid hormone (PTH and 25-hydroxyvitamin D (25(HO)D) were measured in serum and bone markers in serum and urine. Bone densitometry (BMD) of cortical and trabecular bone in the forearm (distal third of the radius (R33%) and ultradistal (RUD), respectively) were performed using X-ray absorptiometry. We found: 1) Low serum 25(HO)D (14.4 + 1.7 ng/ml) at summer's end. 40.5% showed levels < 10 ng/ml. 2) Secondary hyperparathyroidism (PTH: 169.4 + 30.9 pg/ml), 3) Hypocalcemia was observed in 34.5% of elderly people, 4) increased bone turnover in the subpopulation with hypovitaminosis D. 5) The serum levels of 25(HO)D correlated with BMD R33% (r = 0.55, n = 54, P < 0.001), with BMD RUD (r = 0.50, n = 54, P < 0.001) and with PTH (r = -0.44, n = 42, P < 0.01). A deficiency of Vit.D was found in our population of elderly people, probably due to diminished epidermic production of its precursors and/or to scant exposure to sunlight in the elderly. The decrease is associated to age. The positive correlation of 25(HO)D with bone mass (cortical and trabecular bone) underscores its importance for the preservation of bone mass. Hyperparathyroidism, triggered by Vit. D deficit, enhances bone loss.

Human lamellar tendon graft in corneal surgery.

BACKGROUND: Due to the lack of donor corneas or unsuitable conditions for keratoplasty because of preexisting conditions such as vascularization, infections, and multiple rejections, scientists have searched for new synthetic and biological materials that can temporarily or permanently substitute for corneal tissue. The purpose of this article is to show our personal experiences with the use of commercially available donor tendon tissue which has been chemically treated and was developed by Muldashev. METHODS: Ten eyes unsuitable for a corneal allograft underwent lamellar keratoplasty using tendon allografts. Due to differing pathologies various surgical procedures were used. The follow-up period ranged from 6 to 18 months. RESULTS: Transparent or semitransparent corneas resulted in seven of the ten eyes. In the three remaining eyes, conditions were improved for future penetrating keratoplasty because there was a significant decrease in corneal vascularization. The donor tendon was not rejected in any case. CONCLUSIONS: As an alternative therapeutic method, treated human tendon proved effective as donor material for lamellar keratoplasty.