The International journal of developmental biology, 1999
First lower molar development in the mouse was investigated from the cap to early bell stage usin... more First lower molar development in the mouse was investigated from the cap to early bell stage using histology, morphometry, TEM and 3D reconstructions. This period was characterized by the histogenesis of the enamel organ (EO), folding of the epithelio-mesenchymal junction and growth of the tooth. The histogenesis of the EO and appearance of the enamel knot (EK) were initiated at the early cap stage (ED14). From ED14 to ED15, the anterior and posterior extension of the EK was very prominent whilst the length of the enamel organ did not substantially change. The EK appeared as a dynamic and transitory histological structure including dying and replacement cells. At ED16, the folding of the IDE, which extended over the anterior two thirds of the molar, was the first sign of cuspidogenesis. It was accompanied by a local remodeling of the basement membrane (BM): IDE cells involved in this folding transitorily lost contact with the BM which formed a loop in the mesenchyme. During this per...
The International journal of developmental biology, 1999
The X-linked tabby (Ta) syndrome in the mouse is homologous to the hypohidrotic ectodermal dyspla... more The X-linked tabby (Ta) syndrome in the mouse is homologous to the hypohidrotic ectodermal dysplasia (HED) in humans. As in humans with HED, Ta mice exhibit hypohidrosis, characteristic defects of hairs and tooth abnormalities. To analyze the effects of Ta mutation on lower incisor development, histology, morphometry and computer-aided 3D reconstructions were combined. We observed that Ta mutation had major consequences for incisor development leading to abnormal tooth size and shape, change in the balance between prospective crown- and root-analog tissues and retarded cytodifferentiations. The decrease in size of Ta incisor was observed at ED13.5 and mainly involved the width of the tooth bud. At ED14.5-15.5, the incisor appeared shorter and narrower in the Ta than in the wild type (WT). Growth alterations affected the diameter to a greater extent than the length of the Ta incisor. From ED14.5, changes in the shape interfered with the medio-lateral asymmetry and alterations in the ...
The International journal of developmental biology, 1995
The specific arrangement of mouse dentition in each dental quadrant (1-0-0-3) is supposed to resu... more The specific arrangement of mouse dentition in each dental quadrant (1-0-0-3) is supposed to result from the initiation of two independent dental laminae--one for the incisor and one for the three molars. In order to verify whether the adult mouse dental pattern really corresponds to the initial patterning, an analysis of development of the mouse antemolar part of the upper dental quadrant was performed in 10-13 day embryos using histological sections and computer-assisted 3-D reconstructions. Six primary dental laminae contributed to the formation of the upper incisor anlage, which is, therefore, a structure of multiple origin. In contrast to the lower diastema, where only a low epithelial band extended mesially from the first lower molar in 12-13 day embryos, in the upper diastema a dental lamina existed interconnecting transiently the incisor and molar anlagen and giving rise to 3 distinct epithelial rudiments. The rudiments exhibited growth retardation and regressed after reachi...
Growth changes associated with formation of the secondary palate were studied in H-Velaz mouse em... more Growth changes associated with formation of the secondary palate were studied in H-Velaz mouse embryos by morphometric measurement of medial sagittal sections of the heads between days 13 and 15 of embryonic development. Horizontalization of the palatine processes depends primarily on the length of the mandible and is effected by a shift of palatine process material into the supralingual space. The administration of 7.5 mg cortisone acetate im to the female on day 12, of 0.5 mg 6-aminonicotinamide im on day 14, or amniocentesis on day 14 significantly retards growth of the embryo in general and of the mandible in particular without significantly affecting deflexion of the skull base. The different spatial conditions created by disproportion between deflexion of the base and the length of the mandible cause irregularities in the course of horizontalization which lead, as a rule, to cleft palate.
Bulletin du Groupèment international pour la recherche scientifique en stomatologie & odontologie
The X-linked hypohidrotic ectodermal dysplasia in man leads to dental defects and is homologous t... more The X-linked hypohidrotic ectodermal dysplasia in man leads to dental defects and is homologous to the Tabby (Ta) mutation in mouse. We currently investigate the effects of the Ta mutation on odontogenesis. The incisor germ of Ta showed an abnormal size and shape, a change in the balance between prospective crown- and root-analogue tissues and retarded cytodifferentiation. Although the enamel organ in Ta incisors was smaller, a larger proportion of the dental papilla was covered by preameloblasts-ameloblasts. The independent development of the labial and lingual parts of the enamel organ in rodent lower incisor might reflect their heterogeneous origin, as demonstrated for the upper incisor. The mandibular cheek dentition in Ta mice exhibits large variations classified in five morphotypes, based on the tooth number, shape, size and position. In Ta embryos, the mesio-distal extent of the dental epithelium was similar to that in WT, but its segmentation was altered. These morphotypes c...
Hematoporphyrin derivatives have been recommended for photodynamic therapy of malignant processes... more Hematoporphyrin derivatives have been recommended for photodynamic therapy of malignant processes. We administered TPPS4, and Photosan 3 (PS 3) in chick embryo in ovo, with or without subsequent blue light (400-550 nm) irradiation. The aim was to analyze and compare the effects of both substances on organogenesis under different light conditions. The embryotoxic effect (embryonic death and malformations) was detected after a single intra-amniotic injection of 5 different doses (0.3 to 300 microg) of TPPS4 or PS 3 at embryonic day 3-5. The beginning of the embryotoxicity range (minimal embryotoxic dose) was determined in non-irradiated embryos to be between 0.3-3.0 microg PS 3 and 3.0-30.0 microg TPPS4. Malformations of surviving embryos were similar after both substances, represented by trunk hyperlordosis combined with incomplete closure of the ventral body wall and protrusion of viscera as consequences of amnion contraction, reduction limb deformities, eye malformations and cleft ...
Between 1983 and 1997 a total of 2029 children with CL/P (cleft lip, cleft lip and palate or clef... more Between 1983 and 1997 a total of 2029 children with CL/P (cleft lip, cleft lip and palate or cleft palate), who were born in the Bohemian districts of the Czech Republic and who underwent surgery and treatment at the Clinic of Plastic Surgery in Prague, were analysed. One possibility for decreasing the risk of delivery of a child with CL/P is to decrease or eliminate its prenatal exposure to embryotoxic factors. Detection of the embryotoxic factors acting at the individual level (e.g. elevated temperature, drug consumption, x-ray examination or infection) is easier than the detection of embryotoxic factors operating at the population level (e.g. water contamination, air pollution). When searching for the latter factors, we first have to reveal regional differences in CL/P incidence. The aim of the present paper was to determine significant differences in the mean incidence of newborns with CL/P in Bohemian districts during a 15 year period. The correlation between the incidence of C...
Journal of craniofacial genetics and developmental biology
The secondary palate formation in mouse has been associated with the period of fast growth of the... more The secondary palate formation in mouse has been associated with the period of fast growth of the mandible from embryonic days (ED) 13.0 to 16.0. During that time, the incisors and first molars develop from the bud to the bell stage. We investigated the position and growth of the tooth during prenatal elongation of the lower and upper jaws, and searched for the developmental stage when alignment of opposing teeth was achieved. Computer-aided 3D representations allowed us to represent the position of incisors and molars in the embryonic head from ED 13.5 to 18.0 on the basis of data obtained from histological sections. The atlas-hypophysis connection exhibited minimum change in length and orientation during the prenatal period, and thus was used as a reference line. The length of the teeth was calculated from 3D data. The upper first and second molars were longer than the lower ones. When viewed from the upper side, the upper and lower molar primordia were parallel from ED 13.5 to 15...
The nucleolar test was used for evaluation of the rRNA biosynthesis in two populations of chick e... more The nucleolar test was used for evaluation of the rRNA biosynthesis in two populations of chick embryonic cells. In chick embryos, practically 100 per cent of proerythroblasts (starting from embryonic day 3) as well as hepatocytes (starting with embryonic day 5) synthetized nucleolar, i.e. ribosomal RNA. In consequence of a single administration of the well known teratogens--actinomycin D, cyclophosphamide or hydrocortisone--the percentage of rRNA synthetizing proerythroblasts and hepatocytes decreased characteristically--in dependence on the teratogenic drug. The presented method can be employed when toxicity of drugs or other chemical compounds is evaluated in cell populations possessing high metabolic and proliferative activity.
The embryotoxic properties of pyrrolizidine alkaloids senecionine (water insoluble) and senecioni... more The embryotoxic properties of pyrrolizidine alkaloids senecionine (water insoluble) and senecionine-N-oxide (water soluble) were examined using the CHEST method (Chick Embryotoxicity Screening Test). The beginning of the embryotoxicity range for senecionine was found to be between 3-30 micrograms; senecionine-N-oxide, on the other hand, showed no effect even with 100 micrograms dose. On the basis of the theoretical calculation, it can be expected that senecionine embryotoxicity for mammals ranges between 10-100 mg/kg maternal body weight, overlapping in this way the known adult toxicity range. The rat LD50 of most alkaloids known to be significant for human health are in the range of 34-300 mg/kg.
Using the Chick Embrotoxicity Screening Test (CHEST), two samples of bilirubin of different comme... more Using the Chick Embrotoxicity Screening Test (CHEST), two samples of bilirubin of different commercial origin were tested on 2, 3 and 4- day old chick embryos. Water soluble Bilirubin Lachema (containing 20 mg albumin per 1 ml) had no teratogenic effect. On the opposite, Bilirubin Merck (containing 8 mg albumin per 1 ml) manifested an apparent teratogenic potential when single doses 0.2 and 0.6 micrograms were administered intraamniotically on day 4. Dose-dependent malformations of brain and eyes, cleft beak and reduction deformities of limbs were observed. No such effects could be produced by administration of Bilirubin Merck on either day 2 and 3. A tentative explanation of the difference between teratogenic properties of Merck and Lachema bilirubin preparations may be sougth in the different proportion of the free and albumin bound fractions.
Results of direct observation of the effects of 9 drugs with known cardiotoxic properties upon th... more Results of direct observation of the effects of 9 drugs with known cardiotoxic properties upon the embryonic chick heart after intraamniotic administration on days 4 and 3 respectively, revealed the possibility of rough detection of cardiotoxic properties of newly developed drugs using the rapid, simple and inexpensive technique on chicken embryos.
... that thalidomide and accutane were extremely rare exceptions, or is the incidence of congenit... more ... that thalidomide and accutane were extremely rare exceptions, or is the incidence of congenital malformations, when considered alone, not a ... low birth weight, and the use of radioactive iodine is absolutely contraindicated during pregnancy (Bishnoi and Sachmechi, 1996; Ogris ...
Twenty five psychotropic drugs were ranked according to the embryotoxicity dose ranges estimated ... more Twenty five psychotropic drugs were ranked according to the embryotoxicity dose ranges estimated by the Chick Embryotoxicity Screening Test (CHEST). The chick results were compared with some data for common laboratory mammals. In 17 psychotropic drugs a deleterious dose-dependent effect upon the embryonic cardiovascular system was disclosed, terminating in immediate cardiac arrest.
The International journal of developmental biology, 1999
First lower molar development in the mouse was investigated from the cap to early bell stage usin... more First lower molar development in the mouse was investigated from the cap to early bell stage using histology, morphometry, TEM and 3D reconstructions. This period was characterized by the histogenesis of the enamel organ (EO), folding of the epithelio-mesenchymal junction and growth of the tooth. The histogenesis of the EO and appearance of the enamel knot (EK) were initiated at the early cap stage (ED14). From ED14 to ED15, the anterior and posterior extension of the EK was very prominent whilst the length of the enamel organ did not substantially change. The EK appeared as a dynamic and transitory histological structure including dying and replacement cells. At ED16, the folding of the IDE, which extended over the anterior two thirds of the molar, was the first sign of cuspidogenesis. It was accompanied by a local remodeling of the basement membrane (BM): IDE cells involved in this folding transitorily lost contact with the BM which formed a loop in the mesenchyme. During this per...
The International journal of developmental biology, 1999
The X-linked tabby (Ta) syndrome in the mouse is homologous to the hypohidrotic ectodermal dyspla... more The X-linked tabby (Ta) syndrome in the mouse is homologous to the hypohidrotic ectodermal dysplasia (HED) in humans. As in humans with HED, Ta mice exhibit hypohidrosis, characteristic defects of hairs and tooth abnormalities. To analyze the effects of Ta mutation on lower incisor development, histology, morphometry and computer-aided 3D reconstructions were combined. We observed that Ta mutation had major consequences for incisor development leading to abnormal tooth size and shape, change in the balance between prospective crown- and root-analog tissues and retarded cytodifferentiations. The decrease in size of Ta incisor was observed at ED13.5 and mainly involved the width of the tooth bud. At ED14.5-15.5, the incisor appeared shorter and narrower in the Ta than in the wild type (WT). Growth alterations affected the diameter to a greater extent than the length of the Ta incisor. From ED14.5, changes in the shape interfered with the medio-lateral asymmetry and alterations in the ...
The International journal of developmental biology, 1995
The specific arrangement of mouse dentition in each dental quadrant (1-0-0-3) is supposed to resu... more The specific arrangement of mouse dentition in each dental quadrant (1-0-0-3) is supposed to result from the initiation of two independent dental laminae--one for the incisor and one for the three molars. In order to verify whether the adult mouse dental pattern really corresponds to the initial patterning, an analysis of development of the mouse antemolar part of the upper dental quadrant was performed in 10-13 day embryos using histological sections and computer-assisted 3-D reconstructions. Six primary dental laminae contributed to the formation of the upper incisor anlage, which is, therefore, a structure of multiple origin. In contrast to the lower diastema, where only a low epithelial band extended mesially from the first lower molar in 12-13 day embryos, in the upper diastema a dental lamina existed interconnecting transiently the incisor and molar anlagen and giving rise to 3 distinct epithelial rudiments. The rudiments exhibited growth retardation and regressed after reachi...
Growth changes associated with formation of the secondary palate were studied in H-Velaz mouse em... more Growth changes associated with formation of the secondary palate were studied in H-Velaz mouse embryos by morphometric measurement of medial sagittal sections of the heads between days 13 and 15 of embryonic development. Horizontalization of the palatine processes depends primarily on the length of the mandible and is effected by a shift of palatine process material into the supralingual space. The administration of 7.5 mg cortisone acetate im to the female on day 12, of 0.5 mg 6-aminonicotinamide im on day 14, or amniocentesis on day 14 significantly retards growth of the embryo in general and of the mandible in particular without significantly affecting deflexion of the skull base. The different spatial conditions created by disproportion between deflexion of the base and the length of the mandible cause irregularities in the course of horizontalization which lead, as a rule, to cleft palate.
Bulletin du Groupèment international pour la recherche scientifique en stomatologie & odontologie
The X-linked hypohidrotic ectodermal dysplasia in man leads to dental defects and is homologous t... more The X-linked hypohidrotic ectodermal dysplasia in man leads to dental defects and is homologous to the Tabby (Ta) mutation in mouse. We currently investigate the effects of the Ta mutation on odontogenesis. The incisor germ of Ta showed an abnormal size and shape, a change in the balance between prospective crown- and root-analogue tissues and retarded cytodifferentiation. Although the enamel organ in Ta incisors was smaller, a larger proportion of the dental papilla was covered by preameloblasts-ameloblasts. The independent development of the labial and lingual parts of the enamel organ in rodent lower incisor might reflect their heterogeneous origin, as demonstrated for the upper incisor. The mandibular cheek dentition in Ta mice exhibits large variations classified in five morphotypes, based on the tooth number, shape, size and position. In Ta embryos, the mesio-distal extent of the dental epithelium was similar to that in WT, but its segmentation was altered. These morphotypes c...
Hematoporphyrin derivatives have been recommended for photodynamic therapy of malignant processes... more Hematoporphyrin derivatives have been recommended for photodynamic therapy of malignant processes. We administered TPPS4, and Photosan 3 (PS 3) in chick embryo in ovo, with or without subsequent blue light (400-550 nm) irradiation. The aim was to analyze and compare the effects of both substances on organogenesis under different light conditions. The embryotoxic effect (embryonic death and malformations) was detected after a single intra-amniotic injection of 5 different doses (0.3 to 300 microg) of TPPS4 or PS 3 at embryonic day 3-5. The beginning of the embryotoxicity range (minimal embryotoxic dose) was determined in non-irradiated embryos to be between 0.3-3.0 microg PS 3 and 3.0-30.0 microg TPPS4. Malformations of surviving embryos were similar after both substances, represented by trunk hyperlordosis combined with incomplete closure of the ventral body wall and protrusion of viscera as consequences of amnion contraction, reduction limb deformities, eye malformations and cleft ...
Between 1983 and 1997 a total of 2029 children with CL/P (cleft lip, cleft lip and palate or clef... more Between 1983 and 1997 a total of 2029 children with CL/P (cleft lip, cleft lip and palate or cleft palate), who were born in the Bohemian districts of the Czech Republic and who underwent surgery and treatment at the Clinic of Plastic Surgery in Prague, were analysed. One possibility for decreasing the risk of delivery of a child with CL/P is to decrease or eliminate its prenatal exposure to embryotoxic factors. Detection of the embryotoxic factors acting at the individual level (e.g. elevated temperature, drug consumption, x-ray examination or infection) is easier than the detection of embryotoxic factors operating at the population level (e.g. water contamination, air pollution). When searching for the latter factors, we first have to reveal regional differences in CL/P incidence. The aim of the present paper was to determine significant differences in the mean incidence of newborns with CL/P in Bohemian districts during a 15 year period. The correlation between the incidence of C...
Journal of craniofacial genetics and developmental biology
The secondary palate formation in mouse has been associated with the period of fast growth of the... more The secondary palate formation in mouse has been associated with the period of fast growth of the mandible from embryonic days (ED) 13.0 to 16.0. During that time, the incisors and first molars develop from the bud to the bell stage. We investigated the position and growth of the tooth during prenatal elongation of the lower and upper jaws, and searched for the developmental stage when alignment of opposing teeth was achieved. Computer-aided 3D representations allowed us to represent the position of incisors and molars in the embryonic head from ED 13.5 to 18.0 on the basis of data obtained from histological sections. The atlas-hypophysis connection exhibited minimum change in length and orientation during the prenatal period, and thus was used as a reference line. The length of the teeth was calculated from 3D data. The upper first and second molars were longer than the lower ones. When viewed from the upper side, the upper and lower molar primordia were parallel from ED 13.5 to 15...
The nucleolar test was used for evaluation of the rRNA biosynthesis in two populations of chick e... more The nucleolar test was used for evaluation of the rRNA biosynthesis in two populations of chick embryonic cells. In chick embryos, practically 100 per cent of proerythroblasts (starting from embryonic day 3) as well as hepatocytes (starting with embryonic day 5) synthetized nucleolar, i.e. ribosomal RNA. In consequence of a single administration of the well known teratogens--actinomycin D, cyclophosphamide or hydrocortisone--the percentage of rRNA synthetizing proerythroblasts and hepatocytes decreased characteristically--in dependence on the teratogenic drug. The presented method can be employed when toxicity of drugs or other chemical compounds is evaluated in cell populations possessing high metabolic and proliferative activity.
The embryotoxic properties of pyrrolizidine alkaloids senecionine (water insoluble) and senecioni... more The embryotoxic properties of pyrrolizidine alkaloids senecionine (water insoluble) and senecionine-N-oxide (water soluble) were examined using the CHEST method (Chick Embryotoxicity Screening Test). The beginning of the embryotoxicity range for senecionine was found to be between 3-30 micrograms; senecionine-N-oxide, on the other hand, showed no effect even with 100 micrograms dose. On the basis of the theoretical calculation, it can be expected that senecionine embryotoxicity for mammals ranges between 10-100 mg/kg maternal body weight, overlapping in this way the known adult toxicity range. The rat LD50 of most alkaloids known to be significant for human health are in the range of 34-300 mg/kg.
Using the Chick Embrotoxicity Screening Test (CHEST), two samples of bilirubin of different comme... more Using the Chick Embrotoxicity Screening Test (CHEST), two samples of bilirubin of different commercial origin were tested on 2, 3 and 4- day old chick embryos. Water soluble Bilirubin Lachema (containing 20 mg albumin per 1 ml) had no teratogenic effect. On the opposite, Bilirubin Merck (containing 8 mg albumin per 1 ml) manifested an apparent teratogenic potential when single doses 0.2 and 0.6 micrograms were administered intraamniotically on day 4. Dose-dependent malformations of brain and eyes, cleft beak and reduction deformities of limbs were observed. No such effects could be produced by administration of Bilirubin Merck on either day 2 and 3. A tentative explanation of the difference between teratogenic properties of Merck and Lachema bilirubin preparations may be sougth in the different proportion of the free and albumin bound fractions.
Results of direct observation of the effects of 9 drugs with known cardiotoxic properties upon th... more Results of direct observation of the effects of 9 drugs with known cardiotoxic properties upon the embryonic chick heart after intraamniotic administration on days 4 and 3 respectively, revealed the possibility of rough detection of cardiotoxic properties of newly developed drugs using the rapid, simple and inexpensive technique on chicken embryos.
... that thalidomide and accutane were extremely rare exceptions, or is the incidence of congenit... more ... that thalidomide and accutane were extremely rare exceptions, or is the incidence of congenital malformations, when considered alone, not a ... low birth weight, and the use of radioactive iodine is absolutely contraindicated during pregnancy (Bishnoi and Sachmechi, 1996; Ogris ...
Twenty five psychotropic drugs were ranked according to the embryotoxicity dose ranges estimated ... more Twenty five psychotropic drugs were ranked according to the embryotoxicity dose ranges estimated by the Chick Embryotoxicity Screening Test (CHEST). The chick results were compared with some data for common laboratory mammals. In 17 psychotropic drugs a deleterious dose-dependent effect upon the embryonic cardiovascular system was disclosed, terminating in immediate cardiac arrest.
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