Biomedical subjects
Publications and source records attributed to R Pawlicki.
Bones of dinosaurs, Gallimimus bullatus, belonging to selected age groups were studied using an X-ray microanalyser. Content of calcium and phosphorus, their distribution in the investigated areas and Ca/P ratio were determined. The obtained results revealed that the Ca/P ratio highest in the bones of young and middle-aged animals and decreased with age.
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The studies were carried out on teeth extracted for stomatological reasons in the persons with generalized scleroderma. The studies included: morphologic examination of the longitudinal and cross-ground sections in the light and scanning microscope, and microanalytic examination of the longitudinal halves of the teeth in the X-ray microprobe. In the course of scleroderma morphological changes of the mesenchymal origin occurred in the teeth hard tissues. The deviation in the calcium and phosphorus contents was relatively significant and an absence of magnesium in the dentine and distinct dećrease in the calcium-phosphorus ratio were observed.
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The objectives of the paper included a quantitative evaluation qualitative and topographic distribution of four microelements, namely lead, zinc, iron and copper, within enamel prisms, interprismatic region, tubular dentine, and intertubular dentine. The studies were carried out with the use of an X-ray microanalyser and an electron scanning microscope. The values of lead, zinc, iron and copper were higher in the enamel. Topographic curves for all the elements were similar within the enamel and dentin, characterized by unevenly distributed flat zero segments along with several peaks of diversified amplitude, being somewhat denser in the enamel. Qualitative distribution of the elements was also similar, and slightly denser within the enamel, the grains being unevenly scattered.
The study was carried out on dinosaur bones nearly 80 million years old. Samples for examination were prepared with specially elaborated methods. The light and transmission electron microscopic images permitted two kinds of bone lacunae and two types of paralacunar canalicular endings to be distinguished. The lacunae of the first kind were characterized by their elongated shape, their length exceeding their width several times, their dimensions being 31.2/9.4 microns. The lacunae of the other kind were not so long, their mean measurements amounting to 21.32/9.7 microns. Among the paralacunar canalicular endings those of small diameter were more numerous. The canaliculi of wider, funnel-shaped endings amounted to two or three, they were usually localized in the polar part of the lacuna, and were defined as the axial canaliculi. These were canaliculi of a large diameter. The canalicular wall was constructed of collagen fibres. The same fibres were found in the lacunar wall. Also a relationship between the structure of the lacunar wall and the localization of an osteocyte in the lacuna was analysed in the light and electron microscopes. In regard to the structure of the bone lacuna and the localization of an osteocyte in it, zones A and B were distinguished. Zone A had a characteristic loose and disorderly system of collagen fibres building the lacunar wall. The fibres in this area were by nature open to view. Besides, this region of the lacunar wall revealed specific terraced hollows. Zone B was distinguished by a compact system of parallelly arranged collagen fibres, which formed characteristic ridges in the lacunar wall. The localization of the osteocyte in the lacuna was irregular, the pericellular space around it being of variable width. This space was shown to contain mucopolysaccharides. The images obtained from dinosaur bone were compared with those already known for modern bone. These comparisons permitted it to be ascertained that zone A corresponds to a spot in the lacuna in which the osteocyte exhibits a decreased activity. Zone B is the area of the actual direction of the osteocyte's activity aiming at the shaping of the wall of its lacuna. It can be supposed that the widened endings of the paralacunar canaliculi perform more important functions in conveyance, this being evident from comparisons of analogous areas in modern bone.
The observations included the connective tissue laminae originating from samples of the buccal mucous membrane in leukoplakia. Following fixation and dehydration the materials were embedded in Epon 812, and the electronograms for the evaluation were obtained with the use of a Tesla BS 500 electron microscope. The macrophages were encountered close to the basal membrane in the proper lamina. The space between the basal cells and the macrophages was filled with the connective tissue matrix and numerous collagen fibres, as well as the fibroblast cells. Numerous mast cells, characterized by a specific activity, were noted. Additionally, the proper lamina contained few nerve fibres, usually nonmyelinated. The vascular bed was normal. The electronograms in leukoplakia revealed an active synthesis of the connective tissue matrix and collagen fibres. The marked activity of the mast cells was manifested by a high number of cells containing a relatively differentiated amount of granulation. This might be related to the chronic character of the disease. A significant activity of particular elements of the proper lamina, i.e. the cellular elements, collagen fibres and the connective tissue matrix appears to be characteristic of leukoplakia.
The studies were carried out on samples collected from the buccal mucous membrane with highly advanced leukoplakia lesions. The material was fixed in 5% glutaraldehyde buffered to pH 7.4 cacodylate buffer and 1% osmium tetraoxide. Upon dehydration the material was embedded in Epon 812. The electronograms were obtained with the use of a Tesla BS 500 transmission electron microscope. The number of cellular organellae was increased in the basic layer cells of the epithelium. Within the spinous zone a greater number of cellular layers was encountered. The connections between the cells took the form of either desmosomes, or else of direct cytoplasmatic continuity. Among the epithelial cells one might observe macrophages. The epithelial-connective borderline was similar to the normal picture. The obtained results made it possible to regard leukoplakia as a dynamic process, characterized by hyperactivity of all the epithelial layers and cells.
Examination was made on the fossil dinosaur bone 80 million years old. Samples to be examined were prepared by specially elaborated methods. The vascular canal of the dinosaur bone was the object of study. The microscopic and ultrastructural images of the canal revealed three zones therein: proper, perivascular, and vascular. The zone proper was formed by the mineralized wall of the canal, the perivascular zone was a space between the proper and the vascular zone, and the vascular zone was made up of the canal contents identified with blood vessels. The perivascular zone contained collagen fibres; moreover, histochemical examinations revealed in it mucopolysaccharides and lipids. In the wall of the vascular canal (zone proper) the outlets of the bone canaliculi departing from the osteocyte lacunae were detected. The endings of these canaliculi were of two kinds: they were either of the same diameter as the rest of the canaliculus (more numerous) or assumed a widening funnel form as the canaliculi reached the vascular canal (less numerous). By analogy with modern bone appropriate functions may be ascribed to particular zones distinguished in the vascular canal and to the varied endings of the bone canaliculi in the system of conveyance of nutrient and conservative elements as well as metabolites.
The fossil dinosaur bone material, 80 million years old was studied. Samples for analysis were prepared with specially elaborated methods. Images obtained in the light, transmission electron, and scanning electron microscopes revealed the spatial distribution of the osteocytes lying near and far from the vascular canal. Osteocytes of particular kind were found to be present in the immediate vicinity of the canal. The characteristic morphological structure and the localization of this osteocytes between the vascular canal and the osteocytes lying farther from the canal, as well as the mediation of this cell in the system of connections between those elements, served as a basis for the separation of this cells as the intermediary osteocyte. Among the osteocytes situated farther from the vascular canal, three kinds were distinguished: mono-, bi-, and multipolar, according to the kinds of processes and their distribution in relation to the mother cell body. By analogy with modern bone, in dinosaur bone specific functions may be ascribed to the distinguished types of osteocytes and to their differentiated processes in the conduction of nutrient and building elements and metabolites from the vascular canal to the intermediary osteocytes and, with their participation, to other osteocytes lying farther from the canal. This should naturally be analysed as the two-way tract.
Examinations were carried out on the fossil dinosaur bones 80 million years old. Samples for examination were prepared with specially elaborated methods. The light, transmission electron, and sanning electron microscopic images showed the spatial distribution of osteocytes with the system of processes as well as by thin and short ones. The axial processes, retaining the same diameter along their entire course, usually connected the polar parts of the osteocytes which frequently lay considerable distance apart. Such connections were of two kinds. In one case the link was attained by catoplasmic continuity. In the other, the processes belonging to one osteocyte came into contact with definite spot of plasmalemma of another osteocyte by means of a terminal, club-shaped widening, the so called contact body. This spot looked like a hollow or a conical protuberance. In this type of contact there were always tiny apertures between the contacting elements. Moreover, three types of contact, especially between thin processes, were distinguished, i.e. "end to end", "side to side", and "end to side". It seems that direct connections achieved through cytoplasmic continuity are utilized in rapid exchange, which may be indicated by the thickness of processes and the lack of a membranous barrier. The remaining, indirect links (with participation of membranes) though varied in the type of contact seem to fulfil identical functions.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The fossil dinosaur bones over 80 million years old were studied. Samples for examination were prepared with specially elaborated methods. Observations in the light and scanning electron microscope yielded images of the spatial distribution of vascular canals. Besides, the contents of these canals were isolated; the contents fully corresponded to the vascular network in dinosaur bones under study, this permitted the morphological assessment of the vascular system. In the dinosaur bone, independently of its type, i.e. whether it was primitive e.g. plexiform, or Haversian , two blood inflow tracts were distinguished: the main, primary tract running from the marrow cavity, and the secondary tract departing from the periosteum. Examinations made with the use of an X-ray microanalyzer corroborated the essential importance of the tract running from the marrow cavity, revealing the presence of the same material (iron) in the wall of the marrow cavity and in the vascular canals closely connected with this part of the cavity. The bone was found to contain the axial vascular canals, whose course was parallel to the long axis of the bone, and the anastomosing canals perpendicular to them and thereby to the long axis of the bone. The system of the interlinked canals of the two types bounded the bone mass into a prism. The osseous space restricted by these canals was defined as the functional bone area, undoubtedly functionally subject to the control of the surrounding vessels. The spatial system of the functional bone areas was more orderly and these areas were markedly smaller in the primitive, plexiform bone than in the Haversian bone.(ABSTRACT TRUNCATED AT 250 WORDS)
The experiments were carried out on Wistar rats with rickets experimentally induced. The following examinations were made: radiological examinations of the jaws, a teeth analysis in the microanalyser for the distribution of fundamental elements, and ultrastructure observations in the scanning electron microscope. The jaws of the experimental rats were smaller in the radiological picture. The disturbed arrangement of the enamel prisms was found in the enamel substructure of the experimental rats. Phosphorus values in the enamel and dentine were lower in the experimental animals. Calcium to phosphorus ratio was higher in the rachitic rats. Disturbances of calcium-phosphorus balance were observed.
Determination of quantity, distribution and topography of calcium, phosphorus, magnesium and copper in transverse and longitudinal sections of deciduous and early erupted permanent human teeth were made by the use of an x-ray microanalyser and simultaneous analysis of the microstructure of the examined surface by the use of an electron scanning microscope. The examinations demonstrated the higher content of calcium and phosphorus, greater density and more homogenous distribution of these elements in the deciduous teeth. In the permanent teeth characteristic conglomerations of mineral granules were visible in the area corresponding to the dentine tubuli.