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A gap1 can1 mutant of Saccharomyces cerevisiae with a single lysine transport system remaining was used to study detailed kinetics of this transport. Its half-saturation constant was 78 mumol per litre, its maximum rate of transport was 0.29 mumol L-lysine per g dry matter per minute, both parameters being lower by more than an order of magnitude in comparison with the GAP system. The pH optimum lay at very acid values of about 3, the temperature dependence without any transition point showed an activation energy of 48 kJ/mol. The transport was inhibited by common metabolic inhibitors (3'-chlorophenylhydrazonomalononitrile, antimycin, 2-deoxy-D-glucose, sodium arsenate) as well as by a membrane-active one (uranyl nitrate). The specificity of the system was extremely high, none of the natural amino acids acting as competitor to L-lysine. The maximum accumulation ratio attained (at about 5 mg dry matter per mL) was 100: 1-120: 1, in agreement with the measured protonmotive force under the assumption of 1 H+ ion being transported with 1 lysine molecule. The ratio decreased with increasing external concentration of lysine to as little as 4: 1 at 1 mmol lysine per litre. It also decreased with increasing suspension density and it was at extremely low suspension densities (0.2 mg dry matter per mL) that ratios of as much as 500: 1 were reached. Application of group-specific inhibitors showed that the active site of the carrier contains an essential histidine residue.

Although the number of elderly needing health care is increasing in Spain, geriatric patients do not receive enough attention or support when compared to that given in other countries. When the elderly get sick they present peculiar and special problems which should be attended following their needs. Because in hospitals the elderly are cared for in a progressive fashion, geriatrics plays a perfect role in organizing the hospitals and out-patient centers. For the aforementioned, a broad coordination and efficiency within the health centers, units of community social services and the hospital are needed. Geriatric care should be present in the health care system of the government as well as in the private sector.

Reiter's Syndrome (RS) is not common in children and adolescents. From 1982 to 1987 we have seen 13 pediatric patients (8 male and 5 female) with clinical manifestations that characterized RS. Age of onset was 13 years. Clinical findings have been arthritis (100%) involving the knee and ankle joints, heel pain (84%), lumbosacral pain (38%). One to three weeks before joint involvement, six patients (46%) complained of urethritis, 5 (38%) had enteritis and two patients had both. 46% of the patients had HLA-B27 antigen. Radiologic findings were sacroileitis in five patients and calcaneal spurs. All patients were treated with non-steroidal antiinflammatory therapy and, in general, there was a clinical remission in 1-3 months. Nevertheless, after 4 years of follow up, 2 patients had acute relapsing arthritis and 4 had chronic arthropathy. Three patients have developed secondary ankylosing spondylitis. RS is not all that infrequent in pediatric patients with joint involvements if one looks for urethritis, enteritis, eye involvement and cutaneous manifestations. The clinical course is favorable, but there might be some chronic or relapsing cases. Some patients can developed secondary ankylosing spondylitis. For that reason a prolonged follow up of these patients is necessary.

Preincubation of resting cells of Saccharomyces cerevisiae double mutant can1 gap1 (with a single transport system for L-lysine) with metabolic substrates stimulated subsequent uptake of lysine. While in the wild type the stimulation is connected primarily with carrier protein synthesis (delayed, cycloheximide-inhibitable effect) in the mutant an immediate tapping of an energy source (antimycin-inhibited) is practically solely involved.

We present an "in vitro" study of microfiltration in composite resin restorations with a perimetral seal placed totally in cement. We compare the sealing capability of a dentin adhesive (ScotchBond I) used in two ways: habitual, without conditioning dentin and conditioning it by means of the Caridex system. This produced no increasing of sealing capability under the study conditions.