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Biomedical subjects

A Viti

Publications and source records attributed to A Viti.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Microfilament organization in human platelets.

Morphological and biochemical studies suggest that actin in human platelets polymerizes from monomers or oligomers into long filaments more tightly structured in activated than in resting platelets. The polymerization and reorganization of actin filaments are regulated by cellular proteins. Profilin prevents actin polymerization by forming tight complexes with monomeric actin; gelsolin acts both severing filaments and inhibiting their elongation by capping at the barbed end; other actin-binding proteins nucleate polymerization and cross-link actin filaments into networks or bundles. The changes in the actin assembly state, which are under the control of calcium, seem essential for pseudopodal formation. Other platelet processes, such as granule centralization and contractile gel formation, are due to calcium-dependent actin-myosin interaction. In addition, Ca++ seems to inhibit through calmodulin the binding of caldesmon to actin, allowing actin linkage to myosin in a 'flip-flop' fashion.

Actins↗
PubMedDate not supplied

[Auxological data and definitive height in short patients without hormonal deficiencies. A longitudinal study].

61 children (49 males and 12 females) with stature before puberty less than 3. centile were studied. They had been previously diagnosed with the various GH stimulation tests as "constitutional short" and they were measured after reaching final adult height. During longitudinal follow-up, the following auxological data were calculated: height for chronological and bone age sds (HCAsds, HBAsds), height age/bone age ratio (HA/BA), bone age sds (BA sds); all the latter were calculated both in prepuberty and in puberty (mean 1.24 years after the onset of puberty). Target height and predictable height according to Bayley and Pinneau were also calculated. Final height for males was 152-175 cm (mean 162.3) and for females 144-163 cm (mean 151.5). These values were lower than expected with both target height and Bayley and Pinneau prediction, especially if the values of Bayley and Pinneau had been calculated before puberty. In females there was a significant positive correlation with target and final height. In males final height was positively correlated with Target height, with prepuberal data of HCA sds and with pubertal data of HBA sds and HA/BA. A negative correlation was found with final height in males and BA sds during puberty. A delay in bone age, probability, represented a positive factor in increasing final height only if it was maintained during puberty. Bayley and Pinneau's method overestimated final height, in particular when it was used before puberty or with a severe bone delay. Subject with pubertal delay are 2.42 cm taller than normal pubertal children. This difference had been acquired before puberty.

Age Determination by Skeleton↗