Biomedical subjects
Publications and source records attributed to W Woźniak.
The length of the humerus was measured in 69 staged human embryos at developmental stages 18-23 (7 and 8 weeks). It was found that the length of the humerus increases from 2.0 mm at stage 18 to 5.4 mm at stage 23. There were slight variations at certain of the stages investigated. Asymmetry between limb lengths was not found during the embryonic period under examination.
The study was performed in 20 children with partial anterior open bite and in 20 children of a control group. Stereognosis was evaluated on the basis of correct recognition responses to silicone pieces of the different shapes. Pieces were put on the dorsal surface of the tongue close to its apex. It was evident that the stereognostic ability was impaired in children with anterior open bite. This ability also decreased after infiltration anaesthesia of the tongue. The study indicated that the tongue plays an important role in oral stereognosis.
In three human foetuses aged 15, 17, and 23 weeks the number of axons surrounded by single Schwann cells was counted. These Schwann cell/axon complexes form the Schwann units. The largest Schwann units in the foetus aged 15 weeks contained 232 axons, in the foetus of 17 weeks the number was 140 and in the foetus of 23 weeks the largest units contained 65 axons.
Morphometric study was conducted on 28, serially sectioned staged human embryos. The cornea is of equal thickness during its early development (stages 15-17). During developmental stages 18 and 19 (7th week) it is thicker in the central part. In the last embryonic week the peripheral part of the cornea becomes thicker than its central part. The performed study elucidates structural differentiation during development of the cornea.
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The study was conducted on 6 human embryos at stage 13. It was found that the facial-vestibulocochlear complex is closely related to the otic vesicle, and the particular components of that complex may be distinguished. They show different cellular arrangement and shape. The neural crest cells migrating from the dorsal hindbrain are continuous with cells forming the cochlear ganglion. This gives evidence for neural crest contribution to the cochlear ganglion.
Between April 1994 and December 1999, 34 children aged from 5 to 20 years (23 females and 11 males) suffering from osteosarcoma, were treated according to the SFOP-94 protocol. The primary preoperative chemotherapy consists of adriamycin and high-dose methotrexate administration. There were 28 patients with non-metastatic tumours of the extremities and 6 children presented disseminated disease with pulmonary metastases. The primary localization included femur - 20 patients, tibia - 9 patients and humerus - 5 patients. In 26 patients limb-salvage surgery was applied. The programme of chemotherapy was changed in 4 children because of toxicity of methotrexate (1 patient) and progression of disease (3 patients). 26 out of 34 (76,5 %) children are alive including 24 out of 28 patients with localized disease. EFS calculated according to Kaplan-Meier analysis was 60 % at 67 months.
Malignant bone neoplasms contribute to about 7% of paediatric cancer. Within the last 20 years much has changed in cancer treatment. Neoadjuvant chemotherapy, as the first phase of comprehensive treatment, results in regression of the tumour and makes limb salvage surgery possible. An exact analysis of 36 patients with osteosarcoma of different localisation, treated at the National Research Institute of Mother and Child between 1991 and 1996 was carried out. Treatment was started with pre-operative adjuvant chemotherapy with ADM and CDDP, administrated during 6 weeks. The regimen and the length of administration depended on stage of disease and tumour reaction to chemotherapy. Amputations or limb salvage surgery was conducted as a second phase of therapy. Postoperative chemotherapy was given for 6 months. Tumour reaction to chemotherapy was described according to the Huvos scale - percentage map of necrosis and regression areas in the neoplastic tissue. The analysis shows good results after chemotherapy with ADM and CDDP.
In 34 human embryos of 7th and 8th week the length of femur and tibia was measured. It was shown that the length of femur increased from 2.65 mm to 5.10 mm during investigated period. These values for tibia were 2.09 mm and 3.21 mm.
Recent studies have showed that although the most of the neocortical neurons are generated in the VZ and SVZ of the dorsal telencephalon, the ganglionic eminences, particularly the lateral ganglionic eminence contribute neurons to the neocortex. Most of these neurons migrate tangentially.
Recent studies have showed that the ependymal cells and subventricular zone astrocytes are neurosphere-initiating cells and are neural stem cells. They give rise to neurons and glial cells in response to injury and utilization of endogenous stem cells in the treatment of nervous system diseases is important strategy in neurogenesis.
Two forms of neuronal migration have been described in the developing brain: radial migration in which young neurons climb on the shafts of radial glial cells, and tangential migration, in which cells move parallel to the surface of the ventricles and perpendicular to radial glia. The tangential migration occurs in multiple regions of the central nervous system. The relative prevalence of tangential versus radial migration has been estimated to be between 10% to 70%, depending perhaps on the regions of the central nervous system, the time of migration, and animal species studied.
Basing on literature the sources and migration of the olfactory bulb progenitors are described. These progenitors originate in the 1) ventricular zone, 2) subventricular zone, 3) lateral ganglionic eminence, 4) hippocampus, 5) ependymal cells, and 6) subventricular zone astrocytes. Neurons migrate tangentially in the rostral migratory stream. This type of migration is called the chain migration.
The neural stem cells are primary precursors that can self-renew and generate differentiated neurons and glia. Such cells were cultured from adult nervous system. They were identified in the subventricular zone, hippocampus, spinal cord, ependyma and even were cultured from astrocytes. These cells are key players in the formation of the nervous system during development and they hold important clues for brain repair.
Schwann cells are a key regulators of peripheral nerve development, being required for the survival of neurons, the distribution of ion channels along nerve fibers and formation of myelin sheath as well as stimulation of development of the connective tissue sheath. They develop from the neural crest and differentiate into myelin- and non-myelin-forming cells.
Studies were performed on adrenal glands of 7 human embryos between 6 and 8 weeks of intra-uterine life using clone PC-10 mouse serum (Dako, No. M879). During the 6th week, immunoreactivity for the proliferating-cell nuclear antigen (PCNA) was observed only in the central and medial parts of the developing fetal zone of the adrenal gland (75.2 +/- 3.1% of adrenocortical cells showed nuclei stained with anti-PCNA), while the peripheral part was immunonegative. One week later the second outer layer, i.e. the permanent cortex appeared. During the 8th week, the cortex formed two distinct zones: a relatively large and centrally located fetal zone and a thin rim of definitive (permanent) cortex, the later adult adrenal cortex. PCNA-positive cells were present throughout the surface of the gland being most numerous in the center (76.4 +/- 1.4%) and less numerous in the peripheral part (16.6 +/- 2.6%). A very thin layer of permanent cortex surrounding the fetal zone showed less numerous cells stained for PCNA (36.4 +/- 3.4%) as compared with the inner fetal zone. During the 8th week the proliferative cells activity was similar in both zones. The middle proliferative center of the fetal zone disappeared, and all cells of this zone had similar PCNA reactivity.
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Studies of serial sections and reconstructions of embryos at stage 13 (32) postovulatory days) revealed that the cranial neural tube in the investigated embryos possesses 15 neuromers: 1 telencephalic, 3 diencephalic, 3 mesencephalic, and 8 rhombencephalic. Within the primary efferent column all nuclei of the cranial nerves may be distinguished. Also fibers entering brain from cranial nerve ganglia form the common afferent tract. The relation of neuromers to the motor nuclei of the cranial nerves is following: M1-oculomotor, M2-trochlear, Rh2-trigeminal, Rh4-facial, Rh6-glossopharyngeal, Rh7-vagal, Rh8-hypoglossal.