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Biomedical subjects

C Daniele

Publications and source records attributed to C Daniele.

61 records · Page 4Linked to original sources

Analysis of the rhodopsin and peripherin/RDS gene in two families with pattern dystrophy of the retinal pigment epithelium.

Mutations of the peripherin/retinal degeneration slow (RDS) gene have been reported in autosomal dominant retinitis pigmentosa and variable forms of pattern dystrophy of the retinal pigment epithelium. We screened the rhodopsin and the peripherin/RDS gene in the members of two families who presented the clinical features of pattern dystrophy of the retinal pigment epithelium transmitted as an autosomal dominant trait. No migration patterns were detected in single strand conformation polymorphism or hydrolink gels. Both the rhodopsin and the peripherin/RDS gene were normal in one family. In the second, the proband had a normal rhodopsin gene and, although he passed a different haplotype to each of his affected daughters, there was no linkage with the peripherin/RDS gene. The origin of the retinal disturbance in our two pedigrees must therefore be sought, if indeed DNA is involved, elsewhere in the genome. Our findings provide additional evidence that pattern dystrophies of the retinal pigment epithelium may be pathogenically related in spite of different etiological origins. The genetic polymorphism can probably account for the wide range of phenotypes.

Eye Proteins↗

In vitro evaluation of prosthetic heart valves: towards comparable testing.

The Laboratory of Biomedical Engineering (of the National Health Institute, technical body of the Italian Health Service) performs in vitro testing of prosthetic heart valves for mechanical characteristics of materials, fatigue life, and fluidodynamic performance. Testing of materials is directed towards the physicomechanical characterization of the structural components of the valves, e.g. elasticity and resistance to stress of biological tissues and stents. Long-term fatigue life tests are conducted by means of systems which make valves beat at more than 1200 cycles/min. These tests are preceded and followed by geometrical characterization and by steady flow testing in order to obtain information about stenosis and leakage. Special attention is devoted to pulsatile flow testing which is performed on two pulse duplicators: the Dynatek system and the system developed by the University of Sheffield. The same valve was tested with these systems according to their different possible set-ups within the general requirements established by ISO-DIS 5840. This paper presents significant measurements, taking into account their dependence on the systems adopted. Results show (a) the difficulties in comparing test results because of different operating conditions, and (b) the systems' sensitivity with regards to some parameters which affect measurements under comparable set-up conditions (FDA Interlaboratory Comparison Testing Protocol).

Biomechanical Phenomena↗

Approaching comparability and results of pulsatile flow in vitro testing of prosthetic heart valves.

The testing of prosthetic heart valves under pulsatile conditions is still a subject for debate among researchers and competent standardization bodies. The laboratory of Biomedical Engineering, of the Istituto Superiore di Sanità in Rome, has reproduced the current inter-laboratory situation with several test apparatuses, focusing on the definition of significant measurement parameters and procedures to obtain reasonably comparable data. The laboratory is also equipped with a Laser Doppler Anemometer (LDA) and a High-Speed Cinematographic system (HSC). A 29 mm tilting disc valve model, was mounted in the aortic position. Under tightly controlled system conditions the analyses performed on two pulse duplicators (PDs) may be deemed consistent for the valve model tested. Useful results, on the same valve specimen, are reported concerning velocity profiles and turbulent shear stress values (TSS). Furthermore valve motion on the Sheffield PD was monitored during the closing phase, and related cinematic data reported. The applied methodologies can provide relevant data to support surgeon decision making.

Aortic Valve↗