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N Vanmuylder

Publications and source records attributed to N Vanmuylder.

15 recordsLinked to original sources
PubMed2003

Ectopic stapes: a case report with embryologic correlations.

A case report of unilateral congenital stapes misplacement revealed by computed tomography is presented. In addition to this malformation, the malleus was synostosed to the middle ear roof. This kind of stapes ectopia has not been described previously. We have analyzed the malformative pattern in the light of normal and teratologic development of the stapes. In a teratologic model in which retinoic acid is administered to pregnant mice, we have observed an ectopic stapes primordium independent of the otic capsule. We discuss the possible pathogenesis of this abnormality in terms of the genetic events of middle ear development, which can be perturbed by retinoic acid administration.

Adult↗
PubMed2003

Differential expression of S100 calcium-binding proteins in epidermoid cysts, branchial cysts, craniopharyngiomas and cholesteatomas.

AIMS: To investigate whether epidermoid cysts, branchial cysts, craniopharyngiomas and cholesteatomas express S100 proteins differentially by immunohistochemical assaying the presence of S100A1, S100A2, S100A3, S100A4, S100A5, S100A6 and S100B. METHODS AND RESULTS: Immunopositivity/negativity was recorded for each S100 protein in a series of 52 cases consisting of 12 epidermoid cysts, 12 branchial cysts, 15 adamantinomatous craniopharyngiomas and 13 acquired cholesteatomas. Except in the case of the craniopharyngiomas, immunoreactivity was assessed independently in the basal membrane and the basal, the internal and the keratin layers. Our data show that in contrast to S100B, which was rarely expressed, S100A1, S100A2, S100A4 and S100A5 were often present in these four types of epithelial lesions. S100A3 and S100A6 and, to a lesser extent, S100A5 were the most differentially expressed proteins across the different histopathological groups analysed. These three proteins are expressed more often in craniopharyngiomas and cholesteatomas, the two more aggressive types of lesions. CONCLUSIONS: This is the first study to report data on the expression of seven S100 proteins in different histopathological groups of epithelial head and neck lesions, whose precise embryological origins are still a matter of debate. S100 proteins could possibly be used as markers to target this embryonic origin, since our results show that S100A3 and S100A6 (and, to a lesser extent, S100A5) are expressed differentially across these different groups of epithelial lesions.

Adolescent↗
PubMed2002

Computed tomography of a cyclotocephalic neonate.

Cyclotocephaly is a very rare malformative lethal condition which associates otocephaly (extreme hypoplasia of the mandibular arch with agnathia) and cyclopy with proboscis. The head of a cyclotocephalic neonate from our Museum of Anatomy and Embryology was examined using computed tomography (CT). Cutaneous and osseous three-dimensional reformations were performed. Severe bony malformations were observed. A single orbital cavity was surrounded by a cartilaginous proboscis and a median fusion of maxillae, temporal and zygomatic bones. The single orbital cavity contained both paramedial eyeballs (synophthalmia). The external auditory meati and the ear pinnae were also parasagittal. No oral cavity and mandible were observed. Despite the poor conservation state of the brain, lobar holoprosencephaly was suspected. The mesencephalon and pituitary gland were absent. This exercise could lead to optimizing ultrasonographic prenatal diagnosis.

Abnormalities, Severe Teratoid↗
PubMed2002

[Heat shock proteins, embryogenesis and evolution].

We present results about immunohistochemical identification of several heat shock proteins (HSP'S) during mouse normal and teratological embryogenesis. Apoptotic cells express very specifically and precociously HSP 110. This fact permits to identify apoptotic cells before apparition of morphologic features of apoptosis, but also to quantify the process of cell death in some teratological models, particularly administration of retinoic acid. HSP 86 is expressed in some cell populations, and particularly permanent in germ cells. Our observations brought us to discuss the potential protective role of HSP on germ cells, and the consequence of their inactivation in the macroevolution process, as well as the role of apoptosis in teratology.

Animals↗
PubMed2000

Immunocytochemical investigations of heat shock proteins expression during thymic apoptosis induced by glucocorticoids.

The aim of our study was to investigate a possible expression of different HSPs in rat's thymuses after hydrocortisone administration. The thymuses of 41 young rats (25 to 45 days age old) were studied immunocytochemically: 12 rats were not injected, 8 received an injection of physiological serum, and 21 received HC (125 mg/kg). HSP27, 70 and 110 expression was investigated following the PAP method. HSPs27 were expressed neither in normal thymic lobules nor in the cortical thymic cells after HC injection. HSPs70 were objectivated only in 1 control animal, but were frankly expressed in cortical thymic cells 1 to 48 hours after HC injection and remained significantly expressed until the 7th day after HC injection. HSPs 110 were present in only 1 control animal and appeared to be distinctly expressed 48 hours after HC injection. HSPs 70 and 110 were never expressed in the regenerated thymuses 14 and 21 days after HC injection. This report objectivates for the first time 70 and 110 kDa "stress proteins" expression during the thymic apoptosis induced by glucocorticoids.

Animals↗
PubMed2000

Chaperones in the parotid gland: localization of heat shock proteins in human adult salivary glands.

Heat shock proteins (HSPs) are expressed or increased in response to various biological stresses. Moreover, these 'stress proteins' seem to be expressed by some cells living in physiological conditions. From then on, they could play an important physiological role in normal cell functioning. The best-known physiological role of these HSP proteins is to act as 'molecular chaperones'. In this context, we have investigated the immunohistochemical expression of HSP27, HSP70, HSP90 and HSP110 in 10 human adult salivary glands. To highlight the presence of RNAm encoding HSP70, an in situ hybridization was performed. In our material, HSP27 was strongly expressed in the cytoplasm of striated duct cells and in some myoepithelial cells. The same localization was less stained for HSP70 and HSP90. The immunocytochemical reaction was weak or negative for HSP110 in striated ducts. HSPs were not expressed in acinic cells. In situ hybridization gave a positive signal in striated ducts with a probe encoding HSP70. Epithelial cells of the striated ducts and myoepithelial cells expressed HSP27, HSP70 and HSP90. These HSPs probably act in part as molecular chaperones for protein synthesis, transport and for several interactions between HSPs and different proteins.

Adult↗
PubMed2000

[Expression of heat shock proteins in salivary gland tumors. Immunohistochemical study of HSP27, HSP70, HSP90, and HSP110: apropos of 50 cases].

Heat shock proteins (HSPs) are known to be increased in response to biological stress. Recently some authors described their presence in tumors. Our immunohistochemical investigations revealed the expression of HSP27, HSP70, HSP90 and HSP110 in most of benign tumors of salivary glands (33 cases). In the malignant tumors, the reaction was immunopositive for HSP70 and HSP90 in 13/17 cases; but HSP27 and HSP110 were only expressed in 5/17 cases. In conclusion HSPs were expressed less in malignant than in benign cells. These results suggest that the loss of some HSPs may be a possible sign of malignancy.

HSP110 Heat-Shock Proteins↗
PubMed1998

[The role of apoptosis during craniofacial development: concepts and importance in pathology].

Apoptosis is an essential common final pathway in numerous pathological conditions such as malignant tumors, HIV-related CD4 lymphocytes degeneration, neurodegenerative disorders, and in programmed cell death events during normal embryogenesis. Some teratogenic substances for man and laboratory mammals induce an increase of the apoptotic phenomenon, responsible for the occurrence of some precise cranio-maxillo-facial malformations. The study of cell death during normal or teratogenic embryonic development allows to analyse the cellular mechanisms implied in the control of the apoptotic phenomenon, together with its dysregulation ending in pathological processes. We review the cell death phenomenon during cephalogenesis, both during normal embryogenesis, or in teratogenic conditions known to induce cranio-maxillo-facial malformations.

Abnormalities, Drug-Induced↗
PubMed1998

[Stress proteins: expression of a universal phenomenon of cell defense].

Heat shock proteins or stress proteins play a role in adaptative thermotolerance. All cells, procaryotic and eucaryotic, are able to respond to different cellular aggressions by the synthesis of these stress proteins. In normal physiological conditions, they are considered as "molecular chaperones" Their actual role in pathology is still unknown; some of these heat shock proteins may be correlated with the degree of aggressiveness of some tumors.

Adaptation, Physiological↗
PubMed1997

Strong expression of heat shock proteins in growth plate cartilage, an immunohistochemical study of HSP28, HSP70 and HSP110.

Heat shock proteins (HSPs) are known to be increased in response to stresses. Our immunohistochemical investigations revealed the strong expression of a wide range of HSPs in the chondrocytes of the tibial growth plate cartilage from young rats. HSP28 and HSP70 are expressed in the upper part of the hypertrophic zone of the growth plate cartilage. HSP110 are found from the proliferating zone to the hypertrophic zone. On the other hand, application of the TUNEL method has already shown apoptotic DNA fragmentation in the lower part of the proliferating zone. From then one, HSP expression in the chondrocytes may be correlated with apoptosis, but its possible relation with the different events occurring during the calcification process cannot be excluded.

Animals↗
PubMed1997

Myxomatous odontogenic tumor of the maxilla. An unusual case with squamous and mucoproducing epithelial component.

A tumor attached to the amelo-cemental junction of a third molar impacted in the maxillary tuberosity, consisted histologically of a myxomatous stroma, in which multicystic cavities lined by a columnar epithelium and mucoproducing cells, together with an aggressive squamous epithelial component were present. Although the diagnosis of polyp of the maxillary sinus cannot be excluded, this lesion most likely constitutes an unusual presentation for an odontogenic myxoma of the maxilla, in which an aggressive squamous epithelial component is present, along with a mucosecreting glandular component.

Adult↗
PubMedDate not supplied

Cytochemical identification of HSP110 during early mouse facial development.

Apoptotic cell death constitutes a common phenomenon observed during development. This process plays an important role in the regulation of cell populations and in early differentiation of embryonic organs. Several teratologic situations are considered as resulting in a dramatic increase of the apoptotic process. In mammalian cells, heat shock proteins (HSPs), expressed or increased in response to various stresses, act as molecular chaperones in physiological conditions. In order to determine specific histochemical markers of apoptotic cells in normal craniofacial development, we observed the expression of stress proteins (HSPs) 70, 86, and 110. The apoptotic pattern of mesectodermal cell death areas was confirmed using both nuclear staining (Feulgen) and specific labeling of DNA fragmentation (TUNEL). These areas are localized in the proximal parts of the first and second visceral arches. They are located in mesectodermal and ganglionic cells. Apoptotic mesectodermal populations strongly express HSP110, as shown by the cytochemical identification of HSP110 and by double staining HSP110-TUNEL, suggesting that this protein could be considered as a new marker for apoptotic embryonic cells, and could be used in further teratologic studies to better quantify induced cell death.

Animals↗
PubMedDate not supplied

Correlation of HSP110 expression with all-trans retinoic acid-induced apoptosis.

In a previous study, we observed the strong expression of a stress protein of the HSP100/Clp family (HSP110) in apoptotic mesectodermal cells during early mouse facial development. In the present study, we describe the strong expression of the same HSP110 in mesectodermal cells undergoing apoptosis after all-trans retinoic acid (RA) administration. We used a teratological model known to increase cell deaths mainly in the first and second branchial arches during mammalian cephalogenesis: the treatment of E9 mouse embryos with all-trans RA, which results in craniofacial malformations comparable to those that characterize mandibulofacial dysostosis in man. Pregnant NMRI mice were treated with 60 mg/kg body weight of all-trans RA, given orally on day 9 of gestation; embryos were taken 4, 12 or 24 hr after RA administration. The apoptotic pattern of RA-induced cell deaths was confirmed using the dUTP biotin nick-end labeling (TUNEL) method and transmission electron microscopy (TEM). HSP110 expression was detected using an immunohistochemical approach. The increase in the number of TUNEL-positive cells and HSP110-positive cells after all-trans RA administration was quantified in the first branchial arch using a computerized method. Twelve hours after RA administration, the increase in the number of HSP110-positive cells is greater than the increase in the number of TUNEL-positive cells. Twenty-four hours after RA administration, only TUNEL-positive cells remain strong in number. We suggest that HSP110 expression could represent a biochemical event of apoptotic cell death induced by RA, associated with early stages of the apoptotic process. In order to find out if HSP110 expression resulted from neosynthesis, we performed in situ hybridization, which demonstrated that the expression of HSP110 occurred at the level of mRNA.

Animals↗