Lubricin in synovial fluid of mild and severe temporomandibular joint internal derangements

BACKGROUND

To understand the molecular basis of temporomandibular joint (TMJ) pathologies, we aimed to investigate the lubricin levels in the TMJ synovial fluid (SF) of patients with mild to severe internal derangements (IDs).

MATERIAL AND METHODS

A total, 34 joints were the study group. Only patients, with a Wilkes stage of III, IV and V were included, in this sample. Control group consisted of SF from eight joints, from patients undergoing to orthognatic surgery. Concentrations of lubricin in the SF from both samples were measured using ELISA system.

RESULTS

The mean lubricin concentration was 7.029 ± 0.21 µg/mL in stage III patients; 5.64 ± 0.10 µg/mL in stage IV patients, and 4.78 ± 0.11 µg/mL in stage V patients. The lubricin levels from stage IV and stage V patients differed significantly (P ≤ 0.001) from those of control subjects. Lubricin levels were inversely correlated with age and to VAS score.

CONCLUSIONS

The results of this cross-sectional study highlight the relationship between disease severity and the levels of lubricin in TMJ SF. Our findings suggest that novel biotherapeutic approaches, including the administration of recombinant lubricin in the joint cavity, for the treatment of TMJ diseases can be developed.

Increased aquaporin 1 expression in the tunica albuginea of Peyronie's disease patients: an in vivo pilot study

Peyronie's disease (PD) is a localized disorder of the connective tissue of the tunica albuginea (TA) whose etiology has not been elucidated. Although several studies have implicated genetic susceptibility and/or mechanical trauma as triggering events for PD, the underlying molecular mechanisms remain largely unknown. Aquaporin 1 (AQP1) is a water channel protein potentially implicated in connective tissue resistance to mechanical stress, acting primarily by increasing tension within the collagen network. Although it represents a potentially attractive molecular target in PD, to date no studies had ever addressed whether AQP1 is detectable and/or differentially expressed in the TA of these patients. Herein the present study, through immunohistochemical and biochemical approaches, we were able to detect AQP1 expression in the TA of control and PD affected patients. We demonstrated that AQP1-like immunoreactivity and expression are significantly increased in plaques of PD patients Vs controls, implying that AQP1 overexpression might be the consequence of a localized maladaptive response of the connective tissue to repeated mechanical trauma. In summary, these data support the idea that AQP1 might represent a potentially useful biomarker of mechanical injury in the TA and a promising target for the treatment of PD.

Toll-like receptor 4 expression in the epithelium of inflammatory periapical lesions. An immunohistochemical study

Toll-like receptors (TLR) are essential for the innate immune response against invading pathogens and have been described in immunocompetent cells of areas affected by periapical disease. Besides initiating the inflammatory response, they also directly regulate epithelial cell proliferation and survival in a variety of settings. This study evaluates the in situ expression of TLR4 in periapical granulomas (PG) and radicular cysts, focusing on the epithelial compartment.

Twenty-one periapical cysts (PC) and 10 PG were analyzed; 7 dentigerous non-inflamed follicular cyst (DC) served as control. TLR4 expression was assessed by immunohistochemistry. TLR4 immunoreaction products were detected in the epithelium of all specimens, with a higher percentage of immunostained cells in PG. Although TLR4 overexpression was detected in both PG and PC, there were differences that seemed to be related to the nature of the lesion, since in PG all epithelial cells of strands, islands and trabeculae were strongly immunoreactive for TLR4, whereas in PC only some areas of the basal and suprabasal epithelial layers were immunostained. This staining pattern is consistent with the action of TLR4: in PG it could promote formation of epithelial cell rests of Malassez and in epithelial strands and islands the enhancement of cell survival, proliferation and migration, whereas in PC TLR4 could protect the lining epithelium from extensive apoptosis. These findings go some way towards answering the intriguing question of why many epithelial strands or islands in PG and the lining epithelium of apical cysts regress after non-surgical endodontic therapy, and suggest that TLR4 plays a key role in the pathobiology of the inflammatory process related to periapical disease.

Apoptosis activation in human carious dentin. An immunohistochemical study

The exact mechanisms and enzymes involved in caries progression are largely unclear. Apoptosis plays a key role in dentin remodelling related to damage repair; however, it is unclear whether apoptosis in decayed teeth is activated through the extrinsic or the intrinsic pathway. This ex vivo immunohistochemical study explored the localization of TRAIL, DR5, Bcl-2 and Bax, the main proteins involved in apoptosis, in teeth with advanced caries. To evaluate TRAIL, DR5, Bcl-2 and Bax immunoexpressions twelve permanent carious premolars were embedded in paraffin and processed for immunohistochemistry. The results showed that TRAIL and DR5 were overexpressed in dentin and in pulp vessels and mononuclear cells; strong Bax immunostaining was detected in dilated dentinal tubules close to the lesion, and Bcl-2 staining was weak in some dentin areas under the cavity or altogether absent. These findings suggest that both apoptosis pathways are activated in dental caries. Further studies are required to gain insights into its biomolecular mechanisms.

Physical activity ameliorates cartilage degeneration in a rat model of aging: a study on lubricin expression

Osteoarthritis (OA) is a common musculoskeletal disorder characterized by slow progression and joint tissue degeneration. Aging is one of the most prominent risk factors for the development and progression of OA. OA is not, however, an inevitable consequence of aging and age-related changes in the joint can be distinguished from those that are the result of joint injury or inflammatory disease. The question that remains is whether OA can be prevented by undertaking regular physical activity. Would moderate physical activity in the elderly cartilage (and lubricin expression) comparable to a sedentary healthy adult? In this study we used physical exercise in healthy young, adult, and aged rats to evaluate the expression of lubricin as a novel biomarker of chondrocyte senescence. Immunohistochemistry and western blotting were used to evaluate the expression of lubricin in articular cartilage, while enzyme-linked immunosorbent assay was used to quantify lubricin in synovial fluid. Morphological evaluation was done by histology to monitor possible tissue alterations. Our data suggest that moderate physical activity and normal mechanical joint loading in elderly rats improve tribology and lubricative properties of articular cartilage, promoting lubricin synthesis and its elevation in synovial fluid, thus preventing cartilage degradation compared with unexercised adult rats.

Human adult dental pulp CD117/c-kit-positive networks of stromal cells

Dental pulp tissue was collected from 6 healthy adult patients, prior to prosthetic treatments, in order to evaluate the in situ phenotype of dental pulp stromal cells and compare with that of dental pulp stem cells. A CD34-/CD44+/CD105-/CD117+/CD146-/nestin- phenotype of stromal cells in the dental pulp core was found. Cells with a similar phenotype, but CD44-, were found in the cell richzone. Dental pulp stromal networks (DPSNs) were found CD117+/CD44+ in the pulp core, but CD117+/CD44- in the cell rich zone. The c-kit-positive DPSNs were contacting pulp nerves and were, in this regard only, comparable to interstitial Cajal cells. Stromal signalling in dental pulp needs further evaluation, in normal tissue as well as a possible cause of persisting pain after endodontic treatments.

Histochemistry as a unique approach for investigating normal and osteoarthritic cartilage

In this review article, we describe benefits and disadvantages of the established histochemical methods for studying articular cartilage tissue under normal, pathological and experimental conditions. We illustrate the current knowledge on cartilage tissue based on histological and immunohistochemical aspects, and in conclusion we provide a short overview on the degeneration of cartilage, such as osteoarthritis. Adult articular cartilage has low capacity to repair itself, and thus even minor injuries may lead to progressive damage and osteoarthritic joint degeneration, resulting in significant pain and disability. Numerous efforts have been made to implement the knowledge in the study of cartilage in the last years, and histochemistry proved to be an especially powerful tool to this aim.

Immunohistochemical analysis of matrix metalloproteinase-13 in human caries dentin

The immunoexpression profile of matrix metalloproteinase-13 was investigated for the first time in dentin of human caries and healthy teeth. Twelve permanent premolars (10 caries and 2 sound) were decalcified in ethylenediaminetetraacetic acid and processed for embedding in paraffin wax. Sections 3-4 µm in thickness were cut and processed for immunohistochemistry. A mouse monoclonal anti-metalloproteinase-13 antibody was used for localisation using an immunoperoxidase technique. Dentinal immunoreactivity was detected in all teeth; it was weak in sound teeth and strong close to the caries area. These in vivo findings suggest a role for metalloproteinase-13 in the development and progression of adult human dental tissue disorders.

An ex vivo study on immunohistochemical localization of MMP-7 and MMP-9 in temporomandibular joint discs with internal derangement

Internal derangement (ID) is among the most common disorders of the temporomandibular joint (TMJ). Previous research by our group highlighted a correlation between apoptosis and TMJ ID. Metalloproteinases (MMP)-7 and -9 have been shown to play an important role in extracellular matrix ECM) homeostasis and, through it, in joint disc remodelling. The immunohistochemical expression of MMP-7 and -9 was investigated in discs from patients with TMJ ID and from healthy donors and compared with the degree of histological tissue degeneration. The collagen fibre arrangement in pathological discs exhibited varying degrees of disruption. New vessels were consistently detected; endothelial cells from these vessels were immunolabelled with both MMP-7 and MMP-9. More or less intense MMP-7 and MMP-9 immunolabelling was detected in the cytoplasm of disc cells from all patients. MMP-7 and MMP-9 immunostaining was significantly different between pathological and normal discs and correlated with the extent of histopathological degeneration. MMP-7 and MMP-9 upregulation in discs from patients with TMJ ID demonstrates their involvement in disc damage in this disorder. A greater understanding of these processes could help identify ways to curb MMP overproduction without affecting their tissue remodelling action. The design of specific inhibitors for these MMPs would not only help to gain insights into the biological roles of MMPs, but would also aid in developing therapeutic interventions for diseases associated with abnormal ECM degradation.

Beta-catenin and survivin expression in keratocystic odontogenic tumor (KCOT). A comparative immunohistochemical study in primary, recurrent and nevoid basal cell carcinoma syndrome (NBCCS)-associated lesions

AIM

To determine the epithelial expression of β-catenin and survivin in sporadic (primary, and recurrent) and nevoid basal cell carcinoma syndrome (NBCCS) keratocystic odontogenic tumour (KCOT) in order to assess activation of the β-catenin pathway and evidence of apoptotic inhibition, processes that may contribute to the known differences in their biological behaviour.

MATERIALS AND METHODS

Sections from 40 cases of KCOT (19 sporadic/primary; 9 sporadic/recurrent and 12 NBCCS-associated) were immunohistochemically stained for β-catenin and survivin. The extent and intensity of immunoreactivity within the lining epithelium was assessed, using semi-quantitative scales, independently by two pathologists who were blinded to the clinical-pathological data. Data were analysed using Kruskal-Wallis test and, for pair-wise comparisons, Mann-Whitney test with Bonferroni correction.

RESULTS

All cystic epithelial linings stained for β-catenin and survivin but there were differences in the pattern and intensity of staining among KCOT types. Sporadic primary KCOT showed weaker staining for β-catenin (P=0.0003) and survivin (P<0.0048) that was restricted to the basal and para-basal layers only, compared to sporadic recurrent and NBCCS-associated KCOT, which showed expression throughout all epithelial layers. There were no differences in β-catenin expression among recurrent and NBCCS-associated KCOT, whereas the intensity of survivin staining was higher in NBCCS-KCOT (P=0.0003). Nuclear staining for β-catenin was found exclusively in recurrent (5/9 cases) and NBCCS-associated (4/12 cases) KCOT.

CONCLUSION

The data demonstrate β-catenin delocalization and survivin over-expression in recurrent sporadic and NBCCS-associated KCOT suggesting that these pathways related to apoptotic inhibition have a role in KCOT growth and recurrence.

Expression of TRAIL and its receptors DR5 and DcR2 in orthodontic tooth movement

BACKGROUND

TRAIL is a transmembrane protein that induces apoptosis in various tissues including alveolar bone. Its in vitro expression can be activated by several methods, such as RANKL administration and cell scraping. Expression of TRAIL and its receptors DR5 and DcR2 was examined in osteoclast-like cells to analyze their effects on cell lifespan and to explore their role in orthodontic tooth movement.

MATERIALS AND METHODS

Osteoclast-like cells were differentiated from a mouse hematopoietic cell line by stimulation with RANKL for 24 h (T1), 72 h (T2) or 5 days (T3); some cultures were then scraped. Immunostaining for TRAIL, DR5 and DcR2 was evaluated by immunocytochemistry and Western blot analysis in control and treated cells.

RESULTS

Significantly greater TRAIL expression was found in treated osteoclast-like cells at T1 and T3 both on immunocytochemistry and Western blotting. TRAIL expression peaked at T1 and T3 in correspondence with DcR2 and DR5 maxima, respectively.

CONCLUSIONS

These data may contribute to a better understanding of the mechanisms regulating tooth movement and to improve the accuracy of orthodontic treatments.

Aquaporin 1 (AQP1) expression in experimentally induced osteoarthritic knee menisci: an in vivo and in vitro study

Osteoarthritis (OA) of the knee is a major problem in our society. The development of new treatment options for OA is limited, because the pathophysiological mechanisms are not clearly understood, especially on the molecular level. Aquaporin 1 (AQP1) is a specific protein channels for water transport; it is expressed in articular chondrocytes, human synovitis, in chondrocytes of patients with rheumatoid arthritis or OA and in chondrocyte-like cells of human intervertebral disc. The aim of this study was to investigate the expression of AQP1, through immunohistochemistry, immunocytochemistry and Western blot, in experimentally induced OA knee menisci. AQP1 was studied in vivo in knee OA menisci from 36 rats that underwent medial or lateral meniscectomy, and in vitro on fibrochondrocytes derived from knee OA menisci rats. OA in rats was experimentally induced and tested by histomorphometric analysis. Histological results demonstrated structural alterations in OA menisci accompanied by a very strong AQP1 immunohistochemical and immunocytochemical staining. The Western blot analysis confirmed a strong expression of AQP1 in OA fibrochondrocytes cells. The results of the present research suggest that an activation of AQP1, induced by the OA process, may represent an endogenous mechanism, which can be used to control the tissue degeneration within OA articular joints.

Role of β-catenin expression in paediatric mesenchymal lesions: a tissue microarray-based immunohistochemical study

Beta-catenin is a major protein in the Wnt signalling pathway. Although it has been studied in various types of carcinoma, little is known about its expression in mesenchymal tumours. In this study 41 specimens of a variety of mesenchymal childhood tumours were compared to 24 samples of the corresponding adult tumours to assess the diagnostic value of nuclear β-catenin expression using tissue microarray-based immunohistochemistry. Similar to adult sarcoma and fibromatosis, β-catenin was not expressed in the majority of childhood sarcomas, and its nuclear translocation was detected in paediatric fibromatosis; non-negligible levels of nuclear staining in other tumour types demonstrate Wnt pathway activation in mesenchymal neoplasms of childhood and adolescence.

OA cartilage derived chondrocytes encapsulated in poly(ethylene glycol) diacrylate (PEGDA) for the evaluation of cartilage restoration and apoptosis in an in vitro model

Osteoarthritis (OA) is characterized by cartilage attrition, subchondral bone remodeling, osteophyte formation and synovial inflammation. Perturbed homeostasis caused by inflammation, oxidative stress, mitochondrial dysfunction and proapoptotic/antiapoptotic dysregulation is known to impair chondrocyte survival in joint microenvironments and contribute to OA pathogenesis. However, the molecular mechanisms underlying the programmed cell death (apoptosis) of chondral cells are not yet well defined. The present study was conducted to evaluate apoptosis of chondrocytes from knee articular cartilage of patients with OA. The aim of this study was to investigate and compare the apoptosis through the expression of caspase-3 in tissue explants, in cells cultured in monolayer, and in cells encapsulated in a hydrogel (PEGDA) scaffold. Chondrocytes were also studied following cell isolation and encapsulation in poly(ethylene glycol) diacrylate (PEGDA) hydrogels. Specifically, articular cartilage specimens were assessed by histology (Hematoxlyn and Eosin) and histochemistry (Safranin-O and Alcian Blue). The effector of apoptosis caspase-3 was studied through immunohistochemistry, immunocytochemistry and immunofluorescence. DNA strand breaks were evaluated in freshly isolated chondrocytes from human OA cartilage using the TUNEL assay, and changes in nuclear morphology of apoptotic cells were detected by staining with Hoechst 33258. The results showed an increased expression of caspase-3 in tissue explants, in pre-confluent cells and after four passages in culture, and a decreased expression of caspase-3 comparable to control cartilage in cells encapsulated in hydrogels (PEGDA) after 5 weeks in culture. The freshly isolated chondrocytes were TUNEL positive. The chondrocytes after 5 weeks of culture in hydrogels (PEGDA) showed the formation of new hyaline cartilage with increased cell growth, cellular aggregations and extracellular matrix (ECM) production. This is of particular relevance to the use of OA cells and tissue engineering in the therapeutic approach to patients.

Lubricin is expressed in chondrocytes derived from osteoarthritic cartilage encapsulated in poly (ethylene glycol) diacrylate scaffold

Osteoarthritis (OA) is characterized by degenerative changes within joints that involved quantitative and/or qualitative alterations of cartilage and synovial fluid lubricin, a mucinous glycoprotein secreted by synovial fibroblasts and chondrocytes. Modern therapeutic methods, including tissue-engineering techniques, have been used to treat mechanical damage of the articular cartilage but to date there is no specific and effective treatment. This study aimed at investigating lubricin immunohistochemical expression in cartilage explant from normal and OA patients and in cartilage constructions formed by Poly (ethylene glycol) (PEG) based hydrogels (PEG-DA) encapsulated OA chondrocytes. The expression levels of lubricin were studied by immunohistochemistry: i) in tissue explanted from OA and normal human cartilage; ii) in chondrocytes encapsulated in hydrogel PEGDA from OA and normal human cartilage. Moreover, immunocytochemical and western blot analysis were performed in monolayer cells from OA and normal cartilage. The results showed an increased expression of lubricin in explanted tissue and in monolayer cells from normal cartilage, and a decreased expression of lubricin in OA cartilage. The chondrocytes from OA cartilage after 5 weeks of culture in hydrogels (PEGDA) showed an increased expression of lubricin compared with the control cartilage. The present study demonstrated that OA chondrocytes encapsulated in PEGDA, grown in the scaffold and were able to restore lubricin biosynthesis. Thus our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repairing cartilage lesions in patients with OA to reduce at least the progression of the disease.

MMP-13 expression in keratocyst odontogenic tumour associated with NBCCS and sporadic keratocysts

OBJECTIVE

To investigate the matrix metalloproteinase (MMP)-13 expression in associated and non-nevoid basal cell carcinoma syndrome (NBCCS) Odontogenic Keratocysts (OCKs) in order to contribute to a better understanding of the differences in the growth pattern between them.

MATERIALS AND METHODS

Thirty-nine paraffin-embedded blocks of OCKs, 26 sporadic OCKs and 11 NBCCS-associated KCOTs were studied by immunohistochemistry to evaluate MMP-13 expression both in epithelial and stromal layers. A semi-quantitative scale was used to evaluate immunostaining. Obtained data were compared between the two groups, using Fischer's exact test and the chi-square test.

RESULTS

Only 13 of 26 sporadic OCKs showed a positive immunostaining, whilst 11 KCOTs resulted in positive labelling for MMP-13 expression. Moreover, syndromic cysts displayed a more intense and diffuse MMP-13 labelling of the stromal tissue. Instead, in non-syndromic forms, the staining pattern of MMP-13 in stromal tissue was completely absent. Fisher's exact test showed a statistically significant greater prevalence of KCOTs-immunolabelled cysts with respect to sporadic OCKs.

CONCLUSIONS

Results from this study point out that the biological behaviour of these cysts could be related not only to the epithelial layer but also to stromal tissue in that... MMP-13 overexpression in stromal tissue of NBCCS-associated KCOTs could clarify the higher aggressiveness of these cysts.

Hepatocyte growth factor receptor, c-Met, in human embryo salivary glands. An immunohistochemical study

Salivary gland morphogenesis involves complex, coordinated events that include epithelial-mesenchymal interactions. Mesenchymal-epithelial transition factor (c-Met) is the hepatocyte growth factor (HGF) receptor. The latter is a hepatotropic factor originally identified in rat serum and platelets. It is essential in fetal tissue development, where it regulates complex morphogenetic processes including extracellular matrix invasion, cell migration, cell polarization and tubulogenesis. The c-Met/HGF system is believed to participate in epithelial-mesenchymal interactions during development. Twelve human embryonic minor salivary glands were studied by immunohistochemistry to investigate the role of c-Met in human salivary gland development. Strong c-Met immunopositivity in the glands demonstrated that the molecule is involved in their development and suggested a role for the c-Met/HGF system in this process.

TRAIL, DR5 and caspase 3-dependent apoptosis in vessels of diseased human temporomandibular joint disc. An immunohistochemical study

To evaluate the apoptosis involvement in the angiogenesis as a self-limiting process in patients with temporomandibular joint (TMJ) degenerated disc vessels, we assessed, by immunohistochemistry, the detection of TRAIL, its death receptor DR5 and caspase 3. TRAIL, its death receptor DR5 and caspase 3 expression were studied by immunohistochemistry in 15 TMJ discs displaced without reduction and in 4 unaffected discs. These apoptosis molecules were detected in the intima and media layers of newly formed vessels affected discs. In conclusion, vessels apoptosis activation in TMJ disc with ID could be regarded as a self-limiting process that try to leads to vessel regression; in this way an inhibition of angiogenic vessels may prove a key strategy in limiting pathological angiogenesis, by cutting off blood supply to tumors, or by reducing harmful inflammation.

Chondrocyte-like apoptosis in temporomandibular joint disc internal derangement as a repair-limiting mechanism. An in vivo study

Temporomandibular joint internal derangement (TMJ ID) is characterised by disc displacement and degenerative tissue changes involving an active cellular response, with cell phenotype transformation from fibroblast-like to fibrochondrocyte and, eventually, to chondrocyte-like, possibly as a response to abnormal loading. However, only small patches of chondral tissue are detected in TMJ discs with ID. We decided to explore the reasons for such incomplete tissue change, postulating an involvement of the apoptosis process. Twenty-one discs removed from 19 patients with TMJ ID were processed for TRAIL and DR5 immunohistochemical localisation, and subjected to the TUNEL assay. Overexpression of DR5 receptor and its ligand (TRAIL) in chondrocyte-like cells suggested activation of programmed cell death, as also demonstrated by TUNEL-positive cells. The data suggest a failed adaptive response to disc displacement through chondroid metaplasia. The apoptotic death of chondrocyte-like cells, which is at least partly regulated by TRAIL and its death receptor, appears to underpin the failed disc repair, eventually leading to its perforation.

Fluoro-edenite fibres induce lung cell apoptosis: an in vivo study

We previously showed that apoptosis in the lungs of sheep exposed to fluoro-edenite fibres is induced via the receptor pathway. The present study was performed to gain further insights into the mechanisms of activation of programmed cell death induced by the fibres. Fluoro-edenite fibres are similar in size and morphology to some amphibolic asbestos fibres. They have been found in benmoreitic lavas, in the local stone quarry, in building materials and in road paving at Biancavilla, a town in eastern Sicily (Italy), where epidemiological surveys revealed a cluster of mortality from pleural mesothelioma. Inhalation of asbestos fibres can cause chronic inflammation and carcinogenesis. Since fluoro-edenite has been shown to activate the apoptotic process, we set out to characterise the expression of apoptosis-regulating proteins in fluoro-edenite-exposed lung disease and sought to determine if apoptosis results from fluoro-edenite exposure. Lung tissue from apparently healthy sheep habitually grazing near Biancavilla was processed for immunohistochemical localisation of bcl-2 and bax. Results showed epithelial and interstitial bax overexpression, especially in cells directly in contact with the fibres, and negative bcl-2 immunoexpression. TUNEL-positive cells were detected in alveoli and connective tissue. The integrity of alveolar epithelium and alveolar apoptosis are critical determinants in the pathways that initiate fibrogenesis in the lung and fibroblastic foci are usually found close to abnormal or denuded alveolar epithelium. Our results are consistent with the hypothesis that apoptosis is an important mechanism for removing cells with irreparable fluoro-edenite-induced genetic changes that predispose them to a neoplastic evolution.

Effects of exposure to fluoro-edenite fibre pollution on the respiratory system: an in vivo model

An increased standardised rate of mortality from pleural mesothelioma among the population of Biancavilla (Sicily, Italy) has been attributed to exposure to fluoro-edenite fibres. Our aim was to establish whether and how these fibres may induce pathological effects using an in vivo model. Lung tissue collected from 60 healthy sheep selected from six flocks habitually grazing near Biancavilla and from 10 control sheep was fixed formalin and paraffin-embedded; sections were stained with haematoxylin-eosin, Masson trichrome and Gomori argentic impregnation. Histochemical studies and immunohistochemical analysis for the localisation of TRAIL, DR5 and MMP13 were also performed. The lungs of exposed sheep exhibited fibrosis and loss of alveolar architecture with honeycombing of alveolar cavities. Fluoro-edenite fibres were detected close to the alveolar epithelium and interstitia. The parenchyma showed hyaline degeneration and strong PAS-positivity in the interstitium, proteoglycan alterations, reflecting a damaged basal membrane and an involvement of the interstitial matrix. MMP-13 was overexpressed, mainly in fibroblasts and epithelial cells, while positivity for TRAIL and DR5 was detected on alveolar surfaces and in the vascular stroma. The initial pathological event seems to involve first the alveoli and subsequently the interstitium, giving rise to classic honeycombing. The triggering event at the level of type I pneumocytes would damage the cytoplasmic membrane resulting in loss of cell elements and exposure of underlying capillaries, and eventually in a series of reactions including macrophage activation, possible release of growth factors and metaplasic reconstruction of lung alveoli. Immunopositivity for TRAIL and MMP-13 receptor suggests that apoptotic processes may also be activated by fluoro-edenite.

Collagenase-3 (MMP-13) is expressed in periapical lesions: an immunohistochemical study

AIM

To determine whether or not matrix metalloproteinase 13 (MMP-13) is present in periapical granulomas with and without epithelium.

METHODOLOGY

Seventeen open periapical granulomas of pulpal origin (seven lesions without epithelium and 10 with proliferating epithelium) were fixed in formalin and then embedded in paraffin prior to being processed for immunohistochemical analysis. A monoclonal antibody against human MMP-13 was used to evaluate MMP-13 expression. Immunocomplexes were subsequently treated with the secondary antibody and then detected by means of streptavidin peroxidase. Immunoreactivity was visualized by development with 3,3'-diaminobenzidine.

RESULTS

An immunopositive cytoplasmatic reaction for MMP-13 was observed in all the specimens, although the immunostaining by anti-MMP-13 antibody was heterogeneous and its levels varied according to histopathological findings. In periapical lesions without epithelium MMP-13 immunolabelling was detected in a few fibroblast-like cells, and in some plasma cells within the granulomatous tissue. A clear upregulation of MMP-13 expression was detected in periapical lesions with epithelium, especially in small island and thin strands of epithelium.

CONCLUSIONS

The expression pattern of MMP-13 demonstrates that it is involved in the conversion of a periapical granuloma with epithelium into a radicular cyst. This property is related to the ability of MMP-13 to influence not only the migration of epithelial cell but also the invasion of granulomatous tissue.

Detection of vascular endothelial growth factor/ vascular permeability factor in periapical lesions

Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is a multifunctional cytokine. It is overexpressed in several conditions, which are characterized by vascular hyperpermeability and angiogenesis. In this investigation, we have evaluated the possibility that VEGF/VPF could be expressed in periapical lesions. We studied 17 periapical granulomas and 6 periapical cysts by immunohistochemistry. An immunopositive reaction for VEGF/VPF was observed in all 23 periapical lesions; however, the intensity of immunostaining by anti-VEGF antibody varied according to histopathological findings. In periapical granulomas without epithelium, almost all of the inflammatory cells were immunoreactive to anti-VEGF/VIP antibody. In periapical granulomas, which had rests of Malassez in them, some inflammatory cells were stained. On the other hand, epithelial cells always were stained by VEGF/VPF antibody, both in periapical lesions with epithelium and in radicular cysts. This study demonstrated that periapical lesions express VEGF/VPF, although with some differences in cell immunolabeling, which correlated to the lesions' stages of development. Initially, VEGF/VPF would assure angiogenesis and vascular hyperpermeability, resulting in accumulation of inflammatory cells, later it could be involved in cyst fluid accumulation. We hypothesize, therefore, that VEGF/VPF expression plays an important role in the pathogenesis of periapical granulomas and enlargement of radicular cysts by several mechanisms.

[Retrospective study on the prevalence of latex allergic pathology in health personnel]

To evaluate the prevalence of latex sensitisation and latex-related symptoms, we performed a study on 837 hospital employees. All subjects were asked for medical and occupational history, and underwent Skin Prick Test (SPT) with latex and other airborne allergens. The results showed a prevalence of latex sensitisation of 6.1% and a prevalence of symptoms of 5.26%. The most frequent symptoms were oculorhinitis, dermatitis and asthma. The one-year retrospective evaluation showed, in a group of 767 hospital attendants selected by the whole population, an incidence of sensitisation of 0.26%; no new cases of latex-related symptomatology were observed. The improvement of symptoms was due to the reduction of the exposure to latex gloves. The results of the study confirm the importance of prevention strategies.

[Cutaneous histopathologic changes in laboratories working in the processing of petroleum]

Petroleum and its derivatives are a complex mixture of many constituents in varying proportions, such as polycyclic aromatic hydrocarbons, alcohols, ethers and additives. It is well established that petroleum derivatives are absorbed through the skin but exposure has not been quantified. Manifestations of cutaneous exposure vary from squamous cell carcinoma to irritative contact dermatitis such as occurs in the workplace. The aim of the investigation was to evaluate cutaneous histomorphological alterations in a group of 10 healthy workers occupationally exposed to repeated and low amounts of gasoline for a prolonged period. Histological examination and immunocytochemical techniques were performed after taking punch biopsies. The results showed the presence of perivascular lympho-plasma cell infiltration and leucocyte cells scattered in the dermal layer. A mild increase in epidermal Langerhans cells was also observed while the detection of the Ki-67 antigen in keratinocytes gave a normal appearance. In conclusion, the overall histomorphological and immunological features was not specific, but resembled skin reactions due to several irritative agents. Such skin alterations can lead to contact dermatitis.

Heat Shock Protein 27 is overexpressed in the skin of bitumen exposed workers. Early observations

The skin of road pavers is exposed to a large number of compounds such as asphalt, bitumen, amines, polymers, oils, solvents, sand, gravel, crushed rock, mineral wad, ultraviolet light and heat. In order to verify an up-regulation of HSP27, determined by the above mentioned stimuli, we studied, immunohistochemically, the forearm skin of a sample of road pavers occupationally exposed. A total of 25 punch biopsies (3 mm diameters) was obtained from the foream skin of road paver workers (n=16) and a control group (n=5) not exposed. Specimens were sectioned (thickness: 3-4 micron ) and processed for immunohistochemistry. For localization of HSP27, a mouse anti-HSP27 monoclonal antibody was used. In punch biopsies of bitumen exposed workers, HSP27 immunostaining was hemogeneously detected in the whole epidermis including basal cell layer. Immunoreaction products were observed mostly in cytoplasm but also in nuclei. Staining intensity was stronger (grade 3 or 4) than that revealed in normal skin sample.

A cross-sectional study of workers with occupational exposure to petroleum derivatives

Expression of human involucrin (hINV) a protein of the cornified cell envelope, was studied in the skin of gasoline storage workers, in order to evaluate the effects of the exposure to petroleum derivatives. A total of 25 forearm skin punch biopsies were carried out. Twenty of which were performed on exposed subjects and five on controls. The specimens were processed for immunohistochemistry and hINV expression was evaluated using an anti-hINV monoclonal antibody and the ABC technique. Percentage of immunolabeled keratinocytes was significantly higher in subjects exposed to gasoline with respect to the control sample. A premature hINV expression was detected both in suprapapillary and interpapillary keratinocytes. Such overexpression of hINV seems to be related to an attempt of increasing skin defence mechanism. Therefore it was concluded that also in absence of clinical skin manifestation the exposure to gasoline determines an involvement of keratinocytes on molecular basis.

Expression of vimentin intermediate filament in human odontoblast

BACKGROUND

Vimentin (57 Kda) is a cytoskeletal protein. Odontoblasts contain vimentin and it seems that this protein may function to keep the organelles and the nucleus in a definite place. However little is known about vimentin in the cytoskeleton of odontoblast processes. The purpose of the present study was, therefore to immunolocalize vimentin intermediate filament in odontoblast body and process in order to clarify the distribution of this cytoskeletal element.

METHODS

12 extracted intact premolars, from children, were used in the present study. Each specimen was decalcified in EDTA. Each tissue portion was embedded in paraffin. On sections a monoclonal anti-vimentin antibody was applied. The immunoreaction was visualized by ABC technique.

RESULTS

Vimentin was expressed in the cell body and cell process of odontoblasts, however with a different immunolabeling pattern related to the topographical area of observations. In odontoblast cell bodies vimentin showed a perinuclear and cytoplasmatic staining. In the very initial portion of odontoblast process immunoreaction products for vimentin were observed in the core of the process. In the middle zone of dentin vimentin immunoreactions products also showed a granular and cross-bridge arrangements, and also, vimentin was also detected under the plasma membrane, at the periphery of the odontoblast process. Nearby the dentino-enamel junction vimentin immunolabeling was appreciated, mainly under the plasma membrane.

CONCLUSIONS

On the basis of vimentin distribution in the odontoblast process it seems plausible to assume that this IF vimentin is important in forming a flexible scaffold essential for structuring cytoplasm.

[The cervical third of deciduous teeth. An ultrastructural study of the heard tissues by SEM]

As information on amelocemental junction of deciduous teeth is limited, this topographical area was investigated by scanning electron microscopy (SEM) to verify differences from that of permanent teeth. Twenty-six carious and non-carious human maxillary and mandibular primary teeth were placed in a fixative immediately after extraction. Pulpal tissue was removed from the pulpal chambers and root. The primary teeth blocked onto stubs and all specimens were platinum coated and examined by SEM. In these specimens an overlapping of cementum onto to enamel and an edge to edge relationship was dominant. No gaps between enamel and cementum were observed. The amelocemental junction of deciduous teeth seem to differ to that described for permanent teeth.

[Magnetic resonance in the evaluation of parametrial involvement in carcinoma of the cervix uteri]

Cervical carcinoma is one of the most frequent gynecologic malignancies. Its prognosis depends on both tumor volume at diagnosis and its stage. Staging accuracy is important not only for prognosis but also for optimal treatment planning. According to FIGO criteria, carcinomas without parametrial involvement (stage I and limited stage IIA disease) can be surgically treated. For more advanced stages, treatment, in most cases, consists of radiation therapy or chemotherapy alone. The authors evaluated MR accuracy in the diagnosis of parametrial involvement; to this purpose, 32 patients with histologically proven lesions were referred for MR imaging, which was performed with a 0.5 T superconductive magnet. Transverse and sagittal SE images were obtained with T2 weighting (TR 1800 ms, TE 30-100 ms); transverse and sometimes sagittal images were obtained with T1 weighting (TR 450/300 ms, TE 20/30). T1-weighted images distinguished neoplasm from cervical stroma or dense parametrial connective tissue in 40% of cases only. T2-weighted images, instead, demonstrated the difference in all cases, showing tumor as a hyperintense area in 90% of patients. Neoplastic involvement of pericervical connective tissue was diagnosed, with those sequences, on the basis of focal disruptions of the outer hypointense fibrous cervical stroma; findings were correlated with those from a previous clinical staging and in 26/32 patients with pathologic findings. MR accuracy in demonstrating parametrial involvement was 88%, sensitivity was 77% and specificity was 94%. Clinical staging accuracy in the evaluation of this parameter was 66%. In 6 cases with no surgical findings, MR confirmed extensive parametrial and vesical or rectal neoplastic involvement, as diagnosed at clinics. MR imaging, thanks to its multiplanar and multiparametric imaging capabilities is a very reliable technique in the preoperative staging of cervical carcinoma. Moreover, since clinical staging can sometimes underestimate pericervical connective spread, the higher accuracy of MR imaging can help avoid useless interventional procedures.