Comparison of calcium phosphate cement mixture and pure calcium hydroxide as direct pulp-capping agents

This review reports the different genetic factors that have been identified either as risk factor for Alzheimer's disease (AD) or directly causing the disease. First are reviewed epidemiological data and biological mechanisms about the apoplipoprotein E gene allele epsilon 4 that is a major risk factor for Alzheimer's disease. The second part describes the mutations responsible for early-onset autosomal dominant AD found in three different genes. The gene located on chromosome 21 encodes the amyloid precusor protein (APP). The presenilin 1 and presenilin 2 genes, located on chromosome 14 and 1 respectively, encode not yet known membrane proteins.     

3D model retrieval using principal plane analysis and dynamic programming

Three dimensional models play an important role in many applications; the problem is how to select the appropriate models from a 3D database rapidly and accurately. In recent years, a variety of shape representations, statistical methods, and geometric algorithms have been proposed for matching 3D shapes or models. In this paper, we propose a 3D shape representation scheme based on a combination of principal plane analysis and dynamic programming. The proposed 3D shape representation scheme consists of three steps. First, a 3D model is transformed into a 2D image by projecting the vertices of the model onto its principal plane. Second, the convex hall of the 2D shape of the model is further segmented into multiple disjoint triangles using dynamic programming. Finally, for each triangle, a projection score histogram and moments are extracted as the feature vectors for similarity searching. Experimental results showed the robustness of the proposed scheme, which resists translation, rotation, scaling, noise, and destructive attacks. The proposed 3D model retrieval method performs fairly well in retrieving models having similar characteristics from a database of 3D models.     

Hypophosphatemia and the development of rickets in osteopetrotic (op/op) mice

Our previous work has shown that op/op mice hyperabsorb dietary calcium in the vitamin D-deficient state and shunt that calcium into bone. Under these conditions, the op/op mice are hypocalcemic. The purpose of this study was to examine calcium metabolism and bone mineralization in vitamin D-deficient op/op mice. First, the op/op mice and their normal littermates were placed on a vitamin D-deficient, low phosphorus diet to limit bone mineralization. Under these circumstances, op/op mice survived, even when calcium was also removed from the diet. If the diet contained phosphate, op/op mice died from hypocalcemic tetany when calcium was also removed from the diet. Furthermore, serum calcium levels became similar to wild type in the op/op mice administered the vitamin D-deficient, low phosphorus diet, and op/op mice were able to increase serum calcium in response to 1,25-dihydroxyvitamin D3. The op/op mice developed rickets when their serum phosphorus level was too low to support bone mineralization. The op/op mice became hypophosphatemic on regimens in which normal mice were able to maintain normal serum phosphorus levels. It appears that the op/op mouse simply requires a higher dietary calcium and phosphorus level to prevent rickets and hypocalcemic tetany since the bone is not available as a source of these minerals. However, the ability of the op/op mouse to mineralize bone at low serum calcium and phosphorus levels remains unexplained.     

Fivefold symmetry in real and reciprocal spaces

Tetrahedrally close-packed structures with juxtaposed pentagonal antiprisms, such as the μ, C14 Laves and the newly found C phases, were studied by means of HREM and SAD. It was found that each bright spot in the structural image corresponds to an antiprism. Differently oriented domains of these phases intergrow frequently with a fairly good match at the interphase boundary. All diffraction patterns of these phases show a fivefold distribution of spot-pairs, and it is shown that this fivefold symmetry comes from the pentagons and spot-pairs from two pentagonal prisms superposed in antisymmetrical positions.     

Allergic rhinoconjunctivitis treated with intramuscular injection of glucocorticoid

Effects and side effects of injectable depot steroid in the treatment of allergic rhinoconjunctivitis (hay fever) are described. A few controlled studies have shown injectable steroids to be superior to the effect of placebo and locally applied steroid. Over a period of 10 years from 1984-95 only 26 registered side effects were reported to the central Danish register for side effects of drugs (Laegemiddelstyrelsens Bivirkningsregister). Only eight concerned subcutaneous atrophy and in two cases the cutaneous changes persisted. Based on registration of number of treatments in the county of Funen 1996, it is estimated that the use of injectable depot steroids for treatment of hay fever accounts for about 535,000 DDD (defined daily doses corresponding to about 33,000 treatments per year). We conclude that the use of injectable corticosteroids in the treatment of hay fever is common and effective and side effects are very rare. However, injectable corticosteroids should only be used when conventional treatment is not sufficient to control symptoms.