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.

Histopathology and ultrastructure of the thymus in OP/OP rats with special focus on thymic macrophages. Effect of bone marrow transplantation.

The thymi of op/op rats were investigated before and after bone marrow graft. Normal littermates were used as controls. The thymic involution and atrophy in non-treated op/op rats was characterized by the presence of pyknotic thymocytes (apoptosis) and numerous lipid-laden macrophages containing pleiomorphic lysosomes. This thymic atrophy is histologically very similar to the thymic involution induced by glucocorticoids or by stress in normal rats. In treated new born op/op rats, the osteopetrotic process began to be reversed 2 weeks after the graft. The thymus of treated op/op recovered a normal weight and its histology and ultrastructure were quite similar to that of normal littermates. These findings are discussed in relation to the defective macrophage function and cellular immunity impairment reported in osteopetrosis.

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.

Re-establishment of the atomic composition and the oxide structure of contaminated titanium surfaces by means of carbon dioxide laser and hydrogen peroxide: an in vitro study.

BACKGROUND: In clinical situations with peri-implant bone resorption, re-integration of the exposed implant surface is sometimes preferable, which requires a clean surface. Previous investigations have shown that cleaning of contaminated titanium surfaces using chemical and abrasive methods is difficult. PURPOSE: The aim of this investigation was to evaluate the efficacy of different combinations of chemical and physical methods (citric acid, hydrogen peroxide, and carbon dioxide [CO2] laser irradiation) for removal of contaminants and subsequent reconstruction of the surface oxide of intraorally contaminated titanium foils. MATERIALS AND METHODS: Commercially pure titanium foils (99.6%, 5 x 5 mm in size) were contaminated by placement on dentures in volunteering patients, simulating a peri-implantitis situation. The contaminated foils and clean control foils were treated by seven and six combinations of citric acid, hydrogen peroxide, and CO2 laser irradiation, respectively. The effect of the cleaning procedures was evaluated by x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). RESULTS: The initial elemental composition of the contaminated foils was 70% carbon (C), 20% oxygen (O), 10% nitrogen (N), and only traces of titanium (Ti) (< 1%). One treatment proved to be more effective than the others: irradiations by 5-second cycles of superpulsed CO2 laser at a power of 7 W, 10-millisecond pulse width, and with an 80-Hz frequency on a wet surface, followed by repeated application of supersaturated citric acid for 30 seconds, each time followed by rinsing with ultrapure water until all tissue remnants had been removed. Finally, hydrogen peroxide of 10-mM concentration was added to the implant surface and evaporated by CO2 laser at the same settings. This treatment protocol resulted in 10% Ti, 45% O, 41% C, and 2 to 3% N, a composition comparable to that of unused foils: 9% Ti, 40% O, 48% C, and traces of N and chlorine (CI). X-ray photoelectron spectroscopy profiles showed that the thickness of the surface oxide was restored and even augmented with this protocol for treatment of contaminated titanium. CONCLUSION: A combination of citric acid, hydrogen peroxide, and CO2 laser irradiation seems to be effective for cleaning and reestablishment of the atomic composition and oxide structure of contaminated titanium surfaces.

Craniofacial abnormalities induced by retinoic acid: a preliminary histological and scanning electron microscopic (SEM) study.

Exogenous retinoic acid has been found to be teratogenic in animals and man. Craniofacial defects induced by retinoic acid have stimulated considerable research interest. The present report deals with scanning electron microscopical observations of the craniofacial region concurrent with histological examination of craniofacial dysmorphism induced in rat embryos following maternal treatment treated with varying dosages of all-trans-retinoic acid (tretinoin). Two groups of pregnant rats were treated with rat embryos exposed to retinoic acid suspended in corn oil (100 mg/kg b.w. on gestational day 11.5 and 50 mg/kg b.w. on gestational day 10, 11 and 12 respectively). A third group was treated with corn oil (vehicle) while a fourth group remained untreated. A wide spectrum of congenital abnormalities, including exophthalmos, microphthalmia and anophthalmia, maxillo-mandibular dysostosis, micrognathia of both maxilla and mandible, cleft palate, subdevelopment of ear lobe, preauricular tags and macroglossia, were observed in the offspring of retinoic acid treated animals. The abnormalities were both time and dosage dependent, and characteristic of Treacher Collins syndrome when retinoic-acid was administered on gestational day 11.5. In contrast, when retinoic acid was administered were on gestational days 10-12, the defects were similar to those seen in the first and second pharyngeal arch syndrome, as well as in the oculo-auriculo-vertebral spectrum. Whereas our data support the hypothesis that all-trans retinoic-acid disturbs growth and differentiation of several embryonic cell types essential for normal craniofacial development, its mechanism of action remains unclear.

Ultrastructural study on nuclear bodies of the rat parotid glands.

Nuclear bodies of types I, II, III and IV are constantly present in rat parotid glands. They become apparent on the 21st day and afterwards. Type IV nuclear bodies were chiefly found in the striated ducts. Nuclei containing 3 and more nuclear bodies were found as early as the 3rd month, although only in the striated ducts. Nuclear bodies are not related to glycogen or DNA replication but probably to rRNA metabolism. This study leads to a better understanding of nuclear bodies modifications which can be observed ultrastructurally in human salivary glands pathology. Their increased number in some nuclei may be the expression of an alteration of the cell metabolism.

[Microscopy of the thymus in the perinatal period]. / L'examen microscopique du thymus au cours de la périod périnatale.

Simple complementary staining technics are useful to reveal some histological particularities which may be underestimated and unsuspected when are used routinal stainings only. Parallel to hematoxylin eosin, it is recommended to investigate the macrophagic cells by their soudanophilic properties on frozen sections, their ceroid like autofluorescent content by PAS and by paraldehyde fuchsin after oxidation. Eosinophils are constant in the thymus during the neonatal period. They result from a local eosinophilopoiesis. They are contrasted by chromotrope 2R or by anilin blue on ultraviolet light. Semi quantitative determination of cellular density and the importance of the macrophagic activity in the cortex are necessary to definite different stages of thymic atrophy. Anatomoclinical correlations demonstrate relations existing between different degrees of thymic atrophy and duration of illness.

[Expression of heat shock proteins in salivary gland tumors. Immunohistochemical study of HSP27, HSP70, HSP90, and HSP110: apropos of 50 cases]. / Expression des protéines de choc thermique dans les tumeurs des glandes salivaires.

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.

[The gold standard and optimalization of diagnostic choice: the pulmonary nodule and transthoracic pulmonary puncture-biopsy]. / Le "gold standard" et l'optimalisation du choix diagnostique: le nodule pulmonaire et la ponction-biopsie pulmonaire transthoracique.

In this review of the literature, it is emphasized that the published results about the transthoracic pulmonary needle biopsy (TPNB) cannot be readily evaluated due to the inconsistency of the reference tests, the methods and the investigated subjects. Gold-standards for evaluation of lung tumors have been described and are recalled. The limits of the TPNB are pointed out in the diagnosis of solitary pulmonary nodules and benign lesions. In a bayesian approach, it is shown that the TPNB is only useful in confirming an a-priori diagnosis of cancer.

[Stress proteins: expression of a universal phenomenon of cell defense]. / Les protéines de stress: expression d'un phénomène universel de défense cellulaire.

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.

[The role of apoptosis during craniofacial development: concepts and importance in pathology]. / Le rôle de l'apoptose durant le développement crânio-facial: concepts et importance en pathologie.

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.