Biomedical subjects

R Wróblewski

Publications and source records attributed to R Wróblewski.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Microprobe analysis of human otoconia.

Utricular and saccular otoconia (N = 510) from 1 fetus (39th gestational week; Trisomy-18), 2 babies (1 1/2 and 2 months) and 3 adults (58, 61 and 77 years) were analysed with an energy dispersive X-ray microprobe. In all otoconia the elemental composition showed an extremely high concentration of Ca but also Na, Mg, P, S, Cl and K were identified. The presence of non-Ca elements was interpreted as being due to a protein nucleus of the otoconia. Non-Ca elements are more prominent during fetal age and early post-natally than later in life. Old age otoconia contained high concentrations of P which indicates that a ' phosphatization ' of aging otoconia occurs, i.e. calcite otoconia are transformed in situ into apatite by reaction with phosphate ions. The elemental composition of otoconia in Trisomy-18 was similar to that in early postnatal inner ears.

Aged↗

PubMedDate not supplied

X-ray microanalytic studies on developing otoconia.

The onset of otoconial development in the macula utriculi in CBA/CBA mice occurs on the fifteenth and sixteenth gestational days. Our study was concentrated on the early secretion of calcium in the areas of otoconial formation. The epithelial origin of otoconia is documented. Protrusions from supporting cells in the utricular and saccular epithelia contain very large quantities of calcium in addition to the normal cytoplasmic content of elements. The cell protrusions have an elemental composition clearly differing from that of otoconia as well as from neighbouring utricular cells with protrusions. A directed flow of calcium to developing otoconia from the supporting cells of the maculae is suggested.

Animals↗

PubMedDate not supplied

Microanalytic and light microscopic studies on the developing otic capsule.

The structure of the middle layer of the bone of the otic capsule is histologically unique: it is of endochondral origin, has no Haversian canals and the ossification develops from several centres which fuse to form the hardest bone in the body. Our study has been concentrated on the development of the otic capsule in the CBA/CBA mouse, followed from the 13th gestational day to early postnatal age. In the 14th gestational day inner ear, a condensation of mesenchyme is detected around the membranous labyrinth. A cartilaginous capsule is present on the 15th-16th gestational day. Prior to birth, ossification centres occur close to the stapedial footplate. Serial cryosectioning of the newborn inner ear reveals very few regions containing high levels of calcium (microprobe analysis) although by light microscopy, several ossification centres can be identified.

Animals↗

PubMedDate not supplied

Aberrant elemental composition of otoconia in the dancer mouse mutant with a semidominant gene causing a morphogenetic type of inner ear defect.

The elemental composition of otoconia from Jerker and Dancer mouse mutants was analysed in both maculae. A normal elemental content was found in otoconia from Jerker mutants, whereas in the Dancer mutant a large number of otoconia from both maculae contained very high concentrations of phosphorus. In these otoconia, the phosphorus calcium ratio was approximately 1:8, in Jerker (and normal) otoconia approximately 1:150-200. However, otoconia from Dancer mutants occurred with also a normal elemental composition. The increasing content of phosphorus in otoconia may possibly indicate an early onset of aging, i.e. corresponding to a phosphatization process as described in aging human otoconia.

Animals↗