Matrix first, minerals later: fine-tuned dietary phosphate increases bone formation in zebrafish.

Bone matrix formation and mineralization are two closely related, yet separated processes. Matrix formation occurs first, mineralization is a second step strictly dependent on the dietary intake of calcium and phosphorus (P). However, mineralization is commonly used as diagnostic parameter for bone-related diseases.

Zebrafish Tric-b is required for skeletal development and bone cells differentiation.

Introduction: Trimeric intracellular potassium channels TRIC-A and -B are endoplasmic reticulum (ER) integral membrane proteins, involved in the regulation of calcium release mediated by ryanodine (RyRs) and inositol 1,4,5-trisphosphate (IPRs) receptors, respectively. While TRIC-A is mainly expressed in excitable cells, TRIC-B is ubiquitously distributed at moderate level. TRIC-B deficiency causes a dysregulation of calcium flux from the ER, which impacts on multiple collagen specific chaperones and modifying enzymatic activity, leading to a rare form of osteogenesis imperfecta (OI Type XIV).

Compression Fractures and Partial Phenotype Rescue With a Low Phosphorus Diet in the Zebrafish Osteogenesis Imperfecta Model.

Osteogenesis imperfecta (OI) is a group of heritable disorders affecting bone and other connective tissues. Dominant OI forms are mainly caused by mutations in collagen type I. Patients suffer from skeletal deformities, fractures of long bones and vertebral compression fractures from early childhood onward.

More Bone with Less Minerals? The Effects of Dietary Phosphorus on the Post-Cranial Skeleton in Zebrafish.

Dietary phosphorus (P) is essential for bone mineralisation in vertebrates. P deficiency can cause growth retardation, osteomalacia and bone deformities, both in teleosts and in mammals. Conversely, excess P supply can trigger soft tissue calcification and bone hypermineralisation.

Crtap and p3h1 knock out zebrafish support defective collagen chaperoning as the cause of their osteogenesis imperfecta phenotype.

Prolyl 3-hydroxylation is a rare collagen type I post translational modification in fibrillar collagens. The primary 3Hyp substrate sites in type I collagen are targeted by an endoplasmic reticulum (ER) complex composed by cartilage associated protein (CRTAP), prolyl 3-hydroxylase 1 (P3H1) and prolyl cis/trans isomerase B, whose mutations cause recessive forms of osteogenesis imperfecta with impaired levels of α1(I)3Hyp986. The absence of collagen type I 3Hyp in wild type zebrafish provides the unique opportunity to clarify the role of the complex in vertebrate.

[The dental study of patients with leukemic pathology. The clinical aspects].

The authors report a clinical investigation on 49 patients: 9 with acute leukemia and 40 with chronic leukemia. A file suggested by OMS was used to collect all data about patients and case histories. Patients suffering from acute leukemia, admitted to sterile rooms, were submitted to a simple clinical investigation because of their severe general conditions and to avoid any contamination.

Evaluation of the opportunistic microbial flora and of some antimicrobial factors in the oral cavity of leukaemic patients.

The occurrence of opportunistic pathogens and the concentration of some antimicrobial factors in the oral cavity of both acute and chronic leukaemia patients were studied. Enterobacteria were isolated from both dental plaque and crevicular fluid of all the groups examined, with few differences between healthy volunteers and leukaemic subjects; yeasts were found in both the crevicular fluid and the dental plaque samples of chronic leukaemia patients, but only in the plaque of healthy volunteers. Acute leukaemia patients did not have yeasts, but they were the only group colonized by the pseudomonads.

[Handicapped and oral pathology. Clinico-statistical survey].

Dental and periodontal conditions of 80 handicapped adults were examined. The epidemiological survey was made by following the WHO suggestions and showed that there are patients in great need of primary and secondary prevention. The results of the research point out a DMFT of 18.