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1.
Rev Sci Instrum ; 89(10): 10C105, 2018 Oct.
Article in English | MEDLINE | ID: mdl-30399913

ABSTRACT

Concerning plasma diagnostics based on Thomson scattering (TS), precise adjustment and proper alignment is of great importance in order to provide reliable and accurate measurements. Any misalignment could result in an incorrectly determined plasma density or prevent the measurement with this type of diagnostic altogether. Suitable means of alignment monitoring should be integrated into each TS diagnostic system. Variations of commonly used methods are discussed in this article. Correlation of results from alignment control with performed measurements of vibrations on the COMPASS tokamak is presented. Various techniques of optimization of alignment monitoring are shown. The optimal technique, which could be accommodated during the construction of TS diagnostic systems in future fusion devices, is proposed.

2.
Rev Sci Instrum ; 87(11): 11E536, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27910584

ABSTRACT

A new technique for fitting the full radial profiles of electron density and temperature obtained by the Thomson scattering diagnostic in H-mode discharges on the COMPASS tokamak is described. The technique combines the conventionally used modified hyperbolic tangent function for the edge transport barrier (pedestal) fitting and a modification of a Gaussian function for fitting the core plasma. Low number of parameters of this combined function and their straightforward interpretability and controllability provide a robust method for obtaining physically reasonable profile fits. Deconvolution with the diagnostic instrument function is applied on the profile fit, taking into account the dependence on the actual magnetic configuration.

3.
Cesk Slov Oftalmol ; 72(2): 32-8, 2016.
Article in Czech | MEDLINE | ID: mdl-27341097

ABSTRACT

PURPOSE: The aim of this paper is to present the current possibilities in idiopatic intracranial hypertension (IIH) diagnostics. Optical coherence tomography belongs to these possibilities in last few years. The necesarry interdisciplinary co-operation of ophthalmologist and neurologist concerning in IIH patients is pointed out in the mentioned case reports. MATERIAL AND METHODS: The issue of diagnostics and care of IIH patients is presented in two case reports. RESULTS: After ophthalmological and neurological examination the diagnosis of idiopathic intracranial hypertension was assessed and the treatment with acetazolamide was started. The patients have been observed in The department of ophthalmology University hospital in Pilsen during the run of the disease by the neoroophthalmologist. The edema of optic nerve has been monitored by fundoscopy and optical coherence tomography. Initially highly distended retinal nerve fiber layer thickness has been decreased with the normalizing of optic nerve head appearence. The patient´s difficulties have gone off during couple of month and the edema of optic nerve papilla has disappeared. According to the education and the regime acquisition our two patients reduced their body weight, so that they influenced favourably the development of their disorder. CONCLUSION: IIH is consequential disorder causing patient´s crucial restriction in an ordinary lifestyle. It could cause difficult changes in vision. The early diagnosis and proper leading of the therapy is fundamental for the next development of patient´s health. KEY WORDS: idiopatic intracranial hypertension, optical coherence tomography, edema of optic nerve head, papilloedema.


Subject(s)
Cooperative Behavior , Interdisciplinary Communication , Patient Care Team/organization & administration , Pseudotumor Cerebri/diagnosis , Female , Humans , Male , Neurologists , Ophthalmologists , Optic Disk/physiopathology , Papilledema/diagnosis , Retina/physiopathology , Tomography, Optical Coherence/methods
4.
Aust Dent J ; 59 Suppl 1: 55-80, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24495023

ABSTRACT

Tooth development has attracted the attention of researchers since the 19th century. It became obvious even then that morphogenesis could not fully be appreciated from two-dimensional histological sections. Therefore, methods of three-dimensional (3D) reconstructions were employed to visualize the surface morphology of developing structures and to help appreciate the complexity of early tooth morphogenesis. The present review surveys the data provided by computer-aided 3D analyses to update classical knowledge of early odontogenesis in the laboratory mouse and in humans. 3D reconstructions have demonstrated that odontogenesis in the early stages is a complex process which also includes the development of rudimentary odontogenic structures with different fates. Their developmental, evolutionary, and pathological aspects are discussed. The combination of in situ hybridization and 3D reconstruction have demonstrated the temporo-spatial dynamics of the signalling centres that reflect transient existence of rudimentary tooth primordia at loci where teeth were present in ancestors. The rudiments can rescue their suppressed development and revitalize, and then their subsequent autonomous development can give rise to oral pathologies. This shows that tooth-forming potential in mammals can be greater than that observed from their functional dentitions. From this perspective, the mouse rudimentary tooth primordia represent a natural model to test possibilities of tooth regeneration.


Subject(s)
Imaging, Three-Dimensional/methods , Odontogenesis , Tooth/embryology , Animals , Biological Evolution , Dentition , Diastema/embryology , Humans , Image Processing, Computer-Assisted , In Situ Hybridization/methods , Mice , Odontogenesis/genetics , Odontogenesis/physiology , Regeneration , Tooth/physiology , Tooth, Supernumerary/embryology
5.
Aust Dent J ; 59 Suppl 1: 81-100, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24495111

ABSTRACT

During four days of prenatal development in the mouse, the morphology of the first lower molar moves from the early cap to the bell stage. Five phenomena characterize this period: growth of the tooth germ; development of the cervical loop; histogenesis of the enamel organ; folding of the epithelial-mesenchymal junction associated with cusp formation; and change in cellular heterogeneity in the mesenchyme. All these processes are controlled by epithelial-mesenchymal interactions. These complex histo-morphogenetic events have been documented using histological sections and 3D reconstructions. When combined with functional tests in vitro, this approach allowed searching for possible relationships between simultaneous changes occurring in both the epithelial and ecto-mesenchymal compartments. Parallel changes that occur in the two tissues could result from different mechanisms, as illustrated by the increasing number of pre-odontoblasts and pre-ameloblasts during crown growth. Cell division was involved mainly in the ecto-mesenchyme, while proliferation and cell re-organization occurred in the inner dental epithelium. 3D reconstructions also raised still unsolved questions, such as the possible relationship between cusp size and spatial specification of cell kinetic parameters, changes in cell position within the inner dental epithelium, and tracing cell migration in the mesenchyme during development.


Subject(s)
Imaging, Three-Dimensional , Molar/embryology , Odontogenesis/physiology , Ameloblasts/cytology , Animals , Cell Differentiation/physiology , Dentinogenesis/physiology , Epithelium/embryology , Mesoderm/embryology , Mice , Odontoblasts/cytology , Tooth Cervix/embryology , Tooth Crown/embryology , Tooth Migration/embryology
6.
J Dent Res ; 92(3): 222-8, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23315474

ABSTRACT

Tooth morphogenesis involves patterning through the activity of epithelial signaling centers that, among other molecules, secrete Sonic hedgehog (Shh). While it is known that Shh responding cells need intact primary cilia for signal transduction, the roles of individual cilia components for tooth morphogenesis are poorly understood. The clinical features of individuals with Ellis-van Creveld syndrome include various dental anomalies, and we show here that absence of the cilial protein Evc in mice causes various hypo- and hyperplasia defects during molar development. During first molar development, the response to Shh signaling is progressively lost in Evc-deficient embryos and, unexpectedly, the response consistently disappears in a buccal to lingual direction. The important role of Evc for establishing the buccal-lingual axis of the developing first molar is also supported by a displaced activity of the Wnt pathway in Evc mutants. The observed growth abnormalities eventually manifest in first molar microdontia, disruption of molar segmentation and symmetry, root fusions, and delayed differentiation. Analysis of our data indicates that both spatially and temporally disrupted activities of the Shh pathway are the primary cause for the variable dental anomalies seen in patients with Ellis-van Creveld syndrome or Weyers acrodental dysostosis.


Subject(s)
Hedgehog Proteins/physiology , Membrane Proteins/genetics , Molar/growth & development , Odontogenesis/genetics , Tooth Abnormalities/genetics , Tooth Eruption/physiology , Animals , Cell Differentiation/genetics , Cell Proliferation , Cilia , Image Processing, Computer-Assisted , Mice , Mice, Inbred C57BL , Mice, Knockout , Signal Transduction , Tooth Eruption/genetics , Wnt Signaling Pathway/physiology
7.
Neoplasma ; 60(2): 223-31, 2013.
Article in English | MEDLINE | ID: mdl-23259793

ABSTRACT

Disruption of apoptotic pathways belongs to commonly reported molecular mechanisms that underlie cancer drug resistance. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL, Apo2L) is a cytokine of the TNF family with selective anti-tumor activity and minimal toxicity toward healthy tissues. Primary leukemia cells are, however, largely intrinsically resistant to TRAIL-induced apoptosis. In this study we analyzed molecular differences between TRAIL-resistant K562 cell line and TRAIL-sensitive K562 clones. We demonstrate that TRAIL-sensitive K562 cells differ from the TRAIL-resistant cell line by cell surface downregulation of TRAIL decoy receptor 1, upregulation of both TRAIL death receptors, enhanced assembly and improved functioning of the death-inducing signaling complex, and increased cytoplasmic protein expression of CASP8 and key proapoptotic BCL2 members BID, BIM, BAD and BAK. The molecular basis of the intrinsic leukemia cell TRAIL resistance thus appears a consequence of the multi-level disruption of the extrinsic apoptotic pathway. The results of this study also suggest that the leukemia TRAIL-resistance is functional, leaving a possibility of overcoming the resistance by preexposure of the leukemia cells to potent TRAIL sensitizers, e.g. BH3-mimetics.


Subject(s)
Apoptosis , TNF-Related Apoptosis-Inducing Ligand/pharmacology , Drug Resistance, Neoplasm , Humans , K562 Cells , Receptors, TNF-Related Apoptosis-Inducing Ligand/analysis , Signal Transduction , Tumor Necrosis Factor-alpha/pharmacology
8.
Vnitr Lek ; 58(5): 393-5, 2012 May.
Article in Czech | MEDLINE | ID: mdl-22716177

ABSTRACT

We provide an overview of the association between vitamin D and some neurological diseases where the correlation has repeatedly been described. The majority of literature refers to cerebrovascular diseases, followed by multiple sclerosis and cognitive disorders. Vitamin D hypovitaminosis might be associated with the diseases directly or it might contribute to the disease risk factors (typically in cerebrovascular events). Vitamin D hypovitaminosis may also play a role in patients with residual functional involvement due to a neurological disorder (movement disorders, lack of self-sufficiency) and worsen functional status owing to muscle weakness, instability and falls.


Subject(s)
Nervous System Diseases/physiopathology , Vitamin D/physiology , Cerebrovascular Disorders/etiology , Cerebrovascular Disorders/physiopathology , Cognition Disorders/etiology , Cognition Disorders/physiopathology , Humans , Multiple Sclerosis/etiology , Multiple Sclerosis/physiopathology , Nervous System Diseases/etiology , Vitamin D Deficiency/complications
9.
Homo ; 63(2): 81-93, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22425585

ABSTRACT

Sexual dimorphism is responsible for a substantial part of human facial variability, the study of which is essential for many scientific fields ranging from evolution to special biomedical topics. Our aim was to analyse the relationship between size variability and shape facial variability of sexual traits in the young adult Central European population and to construct average surface models of adult males and females. The method of geometric morphometrics allowed not only the identification of dimorphic traits, but also the evaluation of static allometry and the visualisation of sexual facial differences. Facial variability in the studied sample was characterised by a strong relationship between facial size and shape of sexual dimorphic traits. Large size of face was associated with facial elongation and vice versa. Regarding shape sexual dimorphic traits, a wide, vaulted and high forehead in combination with a narrow and gracile lower face were typical for females. Variability in shape dimorphic traits was smaller in females compared to males. For female classification, shape sexual dimorphic traits are more important, while for males the stronger association is with face size. Males generally had a closer inter-orbital distance and a deeper position of the eyes in relation to the facial plane, a larger and wider straight nose and nostrils, and more massive lower face. Using pseudo-colour maps to provide a detailed schematic representation of the geometrical differences between the sexes, we attempted to clarify the reasons underlying the development of such differences.


Subject(s)
Facies , Imaging, Three-Dimensional , Models, Anatomic , Sex Characteristics , Europe , Eye/anatomy & histology , Female , Finite Element Analysis , Forehead/anatomy & histology , Humans , Male , Nose/anatomy & histology , Young Adult
10.
Acta Chir Plast ; 54(2): 39-44, 2012.
Article in English | MEDLINE | ID: mdl-23565843

ABSTRACT

OBJECTIVE: The oronasal cavity in humans develops during embryonic day 30-60. There are three critical periods when this process can be affected, resulting in a specific type of orofacial cleft: cleft lip (CL), cleft palate (CP), or most serious, total cleft lip+palate (CLP). We assessed whether gestational bleeding during early pregnancy might act to produce a non-specific worsening of embryo status resulting in extension of the basic cleft type (CL or CP) into more serious CLP. STUDY DESIGN: In a group of the child patients with orofacial clefts, the cleft spectrum was correlated with first trimester gestational bleeding reported by the mother. Data were also related to the gender of patients, hereditary factors and additional malformations. RESULTS: Among 2524 mothers who gave birth to babies with an orofacial cleft in the Czech Republic during 1983-2009, 253 (10.0%) had gestational bleeding. Among the children with an orofacial cleft, 497 (19.7%) had an orofacial cleft among relatives and 297 (11.8%) exhibited an additional congenital malformation. In comparison with mothers without bleeding, there was significant increase of children with CLP (p < 0.01) at the expense of children with CP, whose number significantly decreased (p < 0.01) in the bleeding mothers. In the group of children with clefts among relatives we did not find any significant change associated with bleeding. The maternal bleeding was more frequent in children with additional malformations, but this difference was not significant (p = 0.112). CONCLUSION: We hypothesize that size/extent and therefore seriousness of orofacial cleft might increase as a consequence of hypoxia resulting from gestational bleeding.


Subject(s)
Cleft Lip/epidemiology , Cleft Palate/epidemiology , Pregnancy Complications, Cardiovascular/epidemiology , Cleft Lip/pathology , Cleft Palate/pathology , Female , Humans , Male , Pregnancy , Pregnancy Trimester, First , Risk Factors
11.
Reprod Toxicol ; 26(2): 178-82, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18606219

ABSTRACT

Conjoined twins are rare variants of monozygotic twins, which result from an incomplete late division of the embryonic disk. Here we report the rarest case of conjoined twins - the male cephalothoracopagus janiceps disymmetros - born in prenatal week 30, from the archive of the Department of Teratology of the Institute of Experimental Medicine AS CR in Prague. The crown-rump length of each twin, 21cm, corresponded to prenatal week 22 in a normal gravidity. The head, chest and upper portion of the abdomen of the twins were fused. The anatomical features of these extremely rare conjoined twins and the observed external anomalies as a narrow nose with a single nostril, male hypoplastic genitalia, partially duplicated sella turcica, spina bifida and further abnormalities are described and documented.


Subject(s)
Abnormalities, Multiple/pathology , Head/abnormalities , Thorax/abnormalities , Twins, Conjoined/pathology , Female , Head/pathology , Humans , Infant, Newborn , Male , Pregnancy , Thorax/pathology
12.
Article in English | MEDLINE | ID: mdl-17588505

ABSTRACT

Phages are gaining importance due to their wide usage. In this work strong anion exchange monolithic chromatographic column was used for single step phage purification. Most of the proteins and DNA were removed and recovery of approximately 70% of infective virus was reproducibly achieved. 30 ml of phage sample was purified in around 10 min.


Subject(s)
Bacteriophage T4/isolation & purification , Chromatography, Ion Exchange/methods , Anion Exchange Resins , Bacteriophage T4/drug effects , Chromatography, High Pressure Liquid , Hydrogen-Ion Concentration , Reproducibility of Results , Sodium Chloride/pharmacology
13.
J Chromatogr A ; 1144(1): 120-5, 2007 Mar 09.
Article in English | MEDLINE | ID: mdl-17204272

ABSTRACT

Certain diagnostic, analytical and preparative applications require the separation of immunoglobulin G (IgG) from immunoglobulin M (IgM). In the present work, different ion-exchange methacrylate monoliths were tested for the separation of IgG and IgM. The strong anion-exchange column had the highest dynamic binding capacity reaching more than 20mg of IgM/ml of support. Additionally, separation of IgM from human serum albumin, a common contaminant in immunoglobulin purification, was achieved on the weak ethylenediamino anion-exchange column, which set the basis for the IgM purification method developed on convective interaction media (CIM) supports. Experiments also confirmed flow independent characteristics of the short monolithic columns.


Subject(s)
Chromatography, High Pressure Liquid/instrumentation , Chromatography, High Pressure Liquid/methods , Immunoglobulin G/isolation & purification , Immunoglobulin M/isolation & purification , Electrophoresis, Polyacrylamide Gel , Humans , Immunoglobulin G/chemistry , Immunoglobulin M/chemistry , Reproducibility of Results , Serum Albumin/chemistry , Serum Albumin/isolation & purification
14.
Acta Chir Plast ; 48(3): 97-102, 2006.
Article in English | MEDLINE | ID: mdl-17165598

ABSTRACT

Orofacial clefts are usually divided into three basic types: isolated cleft lip (CL), cleft lip and palate (CLP) and isolated cleft palate (CP). The incidence of specific cleft types in a population and their relative numbers show specific differences between ethnic groups and races. However, there are no available data about the incidence and relative numbers of orofacial cleft types (CL, CLP, CP) in the gypsy ethnic group. The aim of this study was to compare relative numbers of specific types of orofacial clefts between the Czech gypsy and non-gypsy populations. We conducted a retrospective epidemiological study using a set of all living patients with orofacial clefts born in the Czech Republic from 1964 until 2002. The cleft patients were subdivided into three groups: 5304 non-gypsy children, both parents of whom were non-gypsies (NN), 98 gypsy children, both parents of whom were gypsies (GG) and 18 children with one parent non-gypsy and one parent gypsy (NG). The relative number of isolated CP was 37.1% in NN children. However, the relative number of CP was significantly reduced to 5.1% (P < 0.01) in the GG group. Conversely, the relative number of CLP was higher (P < 0.01) in the GG group (62.2%) in comparison to the NN group (39.2%). The tendency to decrease in the relative number of CP and increase in the relative number of CLP was also apparent in the NG group, but not so well expressed. We hypothesize that the decrease in CP and increase in CLP and CL in gypsies might be caused by their genetic predis-position to CL. Since the CP originates later than CL during embryonic development, some CP arise in embryos with already existing CL giving rise to CLP. Consequently, the missing isolated CP might be hidden in the group of CLP patients postnatally.


Subject(s)
Cleft Palate/epidemiology , Roma , Czech Republic/epidemiology , Female , Genetic Predisposition to Disease , Humans , Male , Retrospective Studies
15.
J Chromatogr A ; 1109(1): 80-5, 2006 Mar 17.
Article in English | MEDLINE | ID: mdl-16517243

ABSTRACT

Monoliths are attractive stationary phases for purification of large biomolecules like proteins because of their flow-unaffected properties. Isolation of histidine containing proteins to high purity can be efficiently performed using metal-chelate interactions within a single chromatographic step. In this work, we investigated properties of commercial metal-chelate methacrylate monoliths-Convective Interaction Media (CIM). Analytical CIM disk monolithic columns and CIM 8 ml monolithic columns were used for purification of tumor necrosis factor-alpha (TNF-alpha) analog LK-801 and green fluorescence protein with 6 histidine tag (GFP-6His). In both cases, purity over 90% was achieved. Dynamic binding capacity at 10% of breakthrough was around 17-18 mg/ml for LK-801 and around 30 mg/ml for GFP-6His. Adsorption isotherm revealed that the maximal capacity is achieved at protein concentration above 60 microg/ml. Dynamic binding capacity and resolution were found to be flow unaffected.


Subject(s)
Chelating Agents/chemistry , Metals/chemistry , Methacrylates/chemistry , Adsorption , Chromatography, High Pressure Liquid/instrumentation , Chromatography, High Pressure Liquid/methods , Copper/chemistry , Electrophoresis, Polyacrylamide Gel , Green Fluorescent Proteins/isolation & purification , Tumor Necrosis Factor-alpha/isolation & purification
16.
J Dent Res ; 85(2): 167-71, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16434736

ABSTRACT

The upper lateral incisor in humans is often affected by dental anomalies that might be explained developmentally. To address this question, we investigated the origin of the deciduous upper lateral incisor (i2) in normal human embryos at prenatal weeks 6-8. We used serial frontal histological sections and computer-aided 3D reconstructions. At embryonic days 40-42, two thickenings of the dental epithelia in an "end-to-end" orientation were separated by a groove at the former fusion site of the medial nasal and maxillary processes. Later, these dental epithelia fused, forming a continuous dental lamina. At the fusion site, i2 started to develop. The fusion line was detectable on the i2 germ until the 8th prenatal week. The composite origin of the i2 may be associated with its developmental vulnerability. From a clinical aspect, a supernumerary i2 might be a form of cleft caused by a non-fusion of the dental epithelia.


Subject(s)
Incisor/embryology , Cleft Palate/embryology , Embryonic Development , Epithelium/embryology , Humans , Incisor/abnormalities , Maxilla , Tooth, Deciduous/embryology
17.
Acta Chir Plast ; 47(3): 85-91, 2005.
Article in English | MEDLINE | ID: mdl-16173518

ABSTRACT

This five-year prospective study demonstrates prosthetic treatment by multidisciplinary therapy: surgeon, orthodontist, and prosthodontist. 10 patients volunteered for the study (a group of 7 men and 3 women at an average age of 33.2 years). 10 obturators, 49 fixed dentures were inserted to the upper jaw. Based on ADA (American Dental Association) recommendation a special card was prepared containing relevant information on the patients. Clinical assessments were carried out in accordance with the US Public Health Service System. In a 5-year period only 50.0% of restorations were excellent, receiving 100% alpha rating. The marginal ridge contour and adaptation of obturator achieved 60.0% alpha rating. The anatomic form of dental arch was destroyed in 50.0%. The presence of caries was not detected. Six teeth were extracted due to periodontal disease. The general contour of the restoration followed the overall contour of the fixed denture in 95.9%. Plaque accumulation was found in 50%. The colour match of crowns was darker and translucent in 27.7%, but discoloration of removable denture was seen in 30.0%. The three case reports demonstrate the long-term stability of treatment (from alpha to charlie evaluation). Attachment retention, fixed and removable denture with metal base are the first method of choice, due to acceptable long-term stability.


Subject(s)
Cleft Lip/therapy , Cleft Palate/therapy , Maxillofacial Prosthesis , Palatal Obturators , Tooth Abnormalities/therapy , Adult , Cleft Lip/complications , Cleft Palate/complications , Dental Prosthesis , Female , Humans , Male , Prospective Studies , Tooth Abnormalities/complications
18.
J Dent Res ; 84(3): 228-33, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15723861

ABSTRACT

In wild-type (WT) mice, epithelial apoptosis is involved in reducing the embryonic tooth number and the mesial delimitation of the first molar. We investigated whether apoptosis could also be involved in the reduction of tooth number and the determination of anomalous tooth boundaries in tabby (Ta)/EDA mice. Using serial histological sections and computer-aided 3D reconstructions, we investigated epithelial apoptosis in the lower cheek dentition at embryonic days 14.5-17.5. In comparison with WT mice, apoptosis was increased mainly mesially in Ta dental epithelium from day 15.5. This apoptosis showed a similar mesio-distal extent in all 5 morphotypes (Ia,b,c and IIa,b) of Ta dentition and eliminated the first cheek tooth in morphotypes IIa,b. Apoptosis did not appear to play any causal role in positioning inter-dental gaps. Analysis of the present data suggests that the increased apoptosis in Ta mice is a consequence of impaired tooth development caused by a defect in segmentation of dental epithelium.


Subject(s)
Apoptosis/physiology , Ectodermal Dysplasia/embryology , Morphogenesis/physiology , Odontogenesis/physiology , Tooth Germ/embryology , Animals , Cheek/embryology , Ectodermal Dysplasia/genetics , Ectodysplasins , Enamel Organ/embryology , Epithelium/embryology , Gestational Age , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Mandible/embryology , Membrane Proteins/genetics , Mice , Mice, Inbred Strains , Mice, Mutant Strains
19.
Arch Oral Biol ; 50(2): 219-25, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15721153

ABSTRACT

OBJECTIVE: A supernumerary cheek tooth occurs mesially to the first molar in tabby/EDA (Ta) mice affected by hypohidrotic ectodermal dysplasia. The supernumerary tooth (S) has been hypothetically homologized to the premolar, which has disappeared during mouse evolution. DESIGN: This hypothesis was tested using available morphological data on the lower cheek teeth in wild type (WT) and Ta mice. RESULTS: The presence of S is accompanied by a reduction in the mesial portion of the M(1) in mutant mice. 3D reconstructions suggest that the S in Ta homo/hemizygous embryos originates from a split off the mesial portion of the first molar (M(1)) cap. In WT embryos, two vestigial tooth primordia are transiently distinct in front of the M(1). The distal vestige has the form of a wide bud and participates during the development of the mesial portion of the M(1). This bud has been homologized with the vestigial primordium of the fourth premolar of mouse ancestors. The premolar disappearance coincided with a mesial lengthening of the M(1) during mouse evolution. The incorporation of the distal premolar vestige into the mesial part of the M(1) in WT embryos can be regarded as a repetition of the premolar disappearance during evolution. CONCLUSION: : Ontogenetic and phylogenetic data support that the S in Ta mice arises due to the segregation of the distal premolar vestige from the molar dentition and thus represents an evolutionary throwback (atavism).


Subject(s)
Bicuspid , Cheek , Membrane Proteins/genetics , Tooth, Supernumerary/pathology , Animals , Biological Evolution , Ectodermal Dysplasia/embryology , Ectodermal Dysplasia/pathology , Ectodysplasins , Homozygote , Mice , Mice, Mutant Strains , Tooth, Supernumerary/embryology
20.
Article in French | MEDLINE | ID: mdl-14535053

ABSTRACT

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 could be explained by a tentative model suggesting that 1) the positions of tooth boundaries differ in Ta and WT molars and among the Ta morphotypes; 2) the tooth patterns are determined by the distal boundary of the most mesial tooth primordium while the distal teeth take advantage of the remaining dental epithelium; 3) one tooth primordium in Ta mice might derive from adjacent parts of two primordia in WT.


Subject(s)
Ectodermal Dysplasia/genetics , Membrane Proteins/genetics , Mutation/genetics , Odontogenesis/genetics , Ameloblasts/pathology , Animals , Cell Differentiation/genetics , Dental Papilla/abnormalities , Disease Models, Animal , Ectodysplasins , Enamel Organ/abnormalities , Epithelium/abnormalities , Epithelium/embryology , Female , Incisor/abnormalities , Incisor/embryology , Male , Mice , Mice, Inbred Strains , Odontometry , Tooth Crown/abnormalities , Tooth Crown/embryology , Tooth Germ/abnormalities , Tooth Root/abnormalities , Tooth Root/embryology
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