The effect of sodium fluoride on trabecular architecture.

The effect of sodium fluoride therapy on iliac trabecular bone has been studied in 15 patients with primary osteoporosis by comparing bone biopsies taken before and after two years of treatment. A marked increase in bone volume (43%) was observed, which was attributable to an increase in trabecular thickness (46%) rather than their number. Because the trabecular bone surface, the trabecular number, the bone volume/trabecular width ratio, and the trabecular terminus number do not change significantly after fluoride treatment, we conclude that fluoride does not induce the de novo generation of trabeculae, nor does it restore trabecular connectivity despite the restoration of bone mass. These data suggest that the restoration of skeletal mass with fluoride may not lead to a comparable decrease in the risk of future fracture.     

An ultrastructural study of Elschnig's pearls in the pseudophakic eye

In two pseudophakic human eyes, obtained post mortem, Elschnig's pearls were visible biomicroscopically. One eye contained a medallion lens and the other an iridocapsular lens (implanted for 53 months and 39 months, respectively). The medallion lens was fixed to the iris but was not attached to the Soemmerring's ring. Elschnig's pearls and star-shaped cells were found on the posterior capsule in the pupillary space. One loop of the iridocapsular lens was encased in the Soemmerring's ring whereas the other was located between the iris and the lens remnants. The Elschnig's pearls were on the anterior side of the ring; only a few were in the pupillary space. Two other pseudophakic eyes with clear posterior capsules also contained small numbers of Elschnig's pearls on or just near the peripheral lens remnants.     

Time-dependent effects of ovarian steroids on tyrosine hydroxylase activity in the limbic forebrain of female rats

Summary In this work, we have studied the time-course of the effects of pharmacological administration of ovarian steroids on tyrosine hydroxylase (TH) activity in the limbic forebrain of ovariectomized rats. Administration of estradiol produced a late decrease in TH activity. This effect was found 24 hours after the last steroid injection, disappearing at 32 hours. It was antagonized by progesterone, since a single injection of this steroid to estradiol-pretreated rats reversed to control values the estradiol-induced decrease. Nevertheless, the administration of progesterone after estradiol treatment caused a short-time decrease in the limbic activity of TH, which was observed 4 hours after the last steroid injection, disappearing subsequently. On the other hand, the administration of progesterone alone produced a biphasic effect, with a reduction at 24 hours, followed by an increase at 32 hours. These effects were only observed in the animals non-treated with estradiol, disappearing with a previous treatment with estrogens. Hence, it can be concluded that both ovarian steroids may affect the limbic TH activity. Thus, estradiol produced a late inhibitory effect on the activity of this enzyme, which was antagonized by progesterone. Administration of the last one to estradiol-treated rats produced a short-time inhibitory effect, whereas its administration to non-treated rats produced a late biphasic effect (inhibition followed by stimulation), which was not observed in estradiol-treated rats.     

Liver transplantation in children with biliary atresia and polysplenia syndrome

Biliary atresia is the most common indication for orthotopic liver transplantation (OLT) in children. The polysplenia syndrome anomalies, which occur in approximately 10% of children with biliary atresia, may represent special difficulties at liver transplantation. We have reviewed our experience with this syndrome in 116 children with biliary atresia who underwent liver transplantation between March 1984 and December 1989. The main features of the polysplenia syndrome, which included absence of the inferior vena cava, preduodenal portal vein, midgut malrotation, aberrant hepatic artery, and situs inversus, were encountered in 12 of the 116 children (10.3%). Severe portal vein hypoplasia (3.5 mm or smaller) was also present in 7 of these children. Eight patients received a complete and four received a reduced liver graft. The vascular anomalies increased the technical difficulty of OLT but could be surmounted, although they did contribute to the peroperative death of one child. The 1-month survival rate was 83% for the 12 children with features of the polysplenia syndrome and 88% for the other 92 children with biliary atresia alone.