Keratoconus: the possible involvement of inflammatory cytokines in its pathogenesis. An experimental study and review of the literature.

OBJECTIVE: Keratoconus (KC) is generally described as a non-inflammatory disease, characterized by thinning in the central region of the cornea with consequent tissue degradation producing impaired visual acuity. MATERIALS AND METHODS: In our experimental study, we analyzed the presence and implications of several inflammatory cytokines in the corneal tissues of patients suffering from keratoconus by immunohistochemical analysis. RESULTS: The analysis showed increased levels of inflammatory factors in the pathological tissues compared to controls, confirming that KC cannot be considered an entirely non-inflammatory pathology and that its etiopathogenesis includes several chronic inflammatory events. CONCLUSIONS: In the light of these results, the classification of KC as an inflammatory pathology or as a pathology related to inflammation might be useful in directing future research aimed at developing effective anti-inflammatory therapies to pharmacologically target the inflammatory mediators which contribute to the development and progression of the disease.

Melatonin role in skeletal muscle disorders.

OBJECTIVE: This review discusses the impact of the neuro-hormone melatonin on skeletal muscle disorders based on recent literature data with the aim to clarify the utility of the melatonin therapy in patients affected by muscle diseases. MATERIALS AND METHODS: It has been pointed out the possible role of melatonin as a food supplement to cure muscular disorders characterized by muscle wasting. Oxidative damage has been proposed as one of the major contributors of the skeletal muscle decline occurring both in physiological and pathological conditions. It is known that excessive oxidant levels lead to mitochondrial damage, and in turn, contribute to apoptotic signaling activation and autophagic impairment. This condition is common in a variety of skeletal muscle disorders. RESULTS: The scientific evidence enhances the antioxidant effect of melatonin, that has been demonstrated by several studies both in vitro and in vivo. This effect counteracts mitochondrial impairments and reduces oxidative stress and autophagic alterations in muscle fibers. Its beneficial role in restoring muscle decline, takes place mainly in atrophic conditions correlated to muscle aging. CONCLUSIONS: The findings of the research suggest that melatonin may be considered as a valid dietary supplement, useful to prevent muscle wasting, in particular, in sarcopenia-associated diseases.

Brain gliomas and growth factors: immunohistochemical, immunofluorescence, flow cytometry and RT-PCR profile in pediatric age.

Gliomas represent over 50% of tumors occurring in children. Evidence suggests that glioma stem cells (GSCs), maintained by the transforming growth factor-beta (TGF-ß1) pathway, and vascularization substantially contribute to tumor aggressiveness. The identification of important angiogenic factors such as vascular endothelial growth factor (VEGF) may represent a crucial step in the therapeutic approach against tumor growth and metastatic diffusion. The aim of this study was to identify the expression of TGF-ß1, VEGF and VEGF-receptors in brain gliomas. Specimens of 16 gliomas and 4 controls from children aged 0.2-14 years were used in the study. Immunohistochemical analysis and gene expression study from specimens was performed. Flow cytometry analysis on GSCs was performed to ascertain the expression of VEGF and VEGF-R2 in the tumor stem cell compartment. Newly diagnosed gliomas mainly showed moderate to strong VEGF immunostaining and increased expression of pro-inflammatory molecules in glioma cells. The proportion of TGF-ß1 positive endothelial cells was markedly lower in normal brain vessels compared to tumor vessels. These findings demonstrate that the glioma mass is constituted by a phenotypically immature anoxic central area with a proliferating hypoxic layer; the peripheral area is characterized by cell types with a higher degree of differentiation expressing pro-angiogenic factors. Our data have proven that GSCs play a central role in promoting glioma neovascularization. These findings are useful to understand glioma vascularization, have relevant implications in the therapeutic options and may favor new insights into stem cells biology and suggest therapeutic opportunities for the anti-vascular treatment strategy.

Environmental nanoparticles are significantly over-expressed in acute myeloid leukemia.

The increase in the incidence of acute myeloid leukemia (AML) may suggest a possible environmental etiology. PM2.5 was declared by IARC a Class I carcinogen. No report has focused on particulate environmental pollution together with AML. The study investigated the presence and composition of particulate matter in blood with a Scanning Electron Microscope coupled with an Energy Dispersive Spectroscope, a sensor capable of identifying the composition of foreign bodies. 38 peripheral blood samples, 19 AML cases and 19 healthy controls, were analyzed. A significant overload of particulate matter-derived nanoparticles linked or aggregated to blood components was found in AML patients, while almost absent in matched healthy controls. Two-tailed Student's t-test, MANOVA and Principal Component Analysis indicated that the total numbers of aggregates and particles were statistically different between cases and controls (MANOVA, P<0.001 and P=0.009 respectively). The particles detected showed to contain highly-reactive, non-biocompatible and non-biodegradable metals; in particular, micro- and nano-sized particles grouped in organic/inorganic clusters, with statistically higher frequency of a subgroup of elements in AML samples. The demonstration, for the first time, of an overload of nanoparticles linked to blood components in AML patients could be the basis for a possible, novel pathogenetic mechanism for AML development.

Three-dimensional apoptotic nuclear behavior analyzed by means of Field Emission in Lens Scanning Electron Microscope.

Apoptosis is an essential biological function required during embryogenesis, tissue homeostasis, organ development and immune system regulation. It is an active cell death pathway involved in a variety of pathological conditions. During this process cytoskeletal proteins appear damaged and undergo an enzymatic disassembling, leading to formation of apoptotic features. This study was designed to examine the three-dimensional chromatin behavior and cytoskeleton involvement, in particular actin re-modeling. HL-60 cells, exposed to hyperthermia, a known apoptotic trigger, were examined by means of a Field Emission in Lens Scanning Electron Microscope (FEISEM). Ultrastructural observations revealed in treated cells the presence of apoptotic patterns after hyperthermia trigger. In particular, three-dimensional apoptotic chromatin rearrangements appeared involving the translocation of filamentous actin from cytoplasm to the nucleus. FEISEM immunogold techniques showed actin labeling and its precise three-dimensional localization in the diffuse chromatin, well separated from the condensed one. The actin presence in dispersed chromatin inside the apoptotic nucleus can be considered an important feature, indispensable to permit the apoptotic machinery evolution.

Silver-polysaccharide antimicrobial nanocomposite coating for methacrylic surfaces reduces Streptococcus mutans biofilm formation in vitro.

OBJECTIVES: The aim of this study was to determine the in vitro microbiological performances of a lactose-modified chitosan (Chitlac) coating inside which silver nanoparticles were embedded (Chitlac-nAg) for BisGMA/TEGDMA methacrylic specimens. METHODS: Different concentrations of nAg inside Chitlac coating were tested (1 mM, 2 mM, 5 mM). Specimen surface was analyzed by means of field-emission scanning electron microscopy (FEISEM) and energy-dispersive X-ray spectroscopy (EDS). A 48 h monospecific Streptococcus mutans biofilm was developed over the specimen surfaces using a modified drip-flow bioreactor; adherent viable biomass was assessed by MTT test and biofilm was imaged by confocal laser-scanning microscopy (CLSM). RESULTS: The presence of finely dispersed nanoparticles inside the Chitlac coating was confirmed by FEISEM and EDS analysis. All nanoparticles were embedded in the Chitlac coating layer. Chitlac-nAg coatings were able to significantly decrease biofilm formation depending on the nAg concentration, reaching a -80% viable biomass decrease when the 5 mM nAg-Chitlac group was confronted to non-coated control specimens. CLSM analysis did not provide evidence of a contact-killing activity, however the antibacterial Chitlac-nAg coating was able to alter biofilm morphology preventing the development of mature biofilm structures. CONCLUSIONS: The microbiological model applied in this study helped in assessing the antibacterial properties of a coating designed for methacrylate surfaces. CLINICAL SIGNIFICANCE: A microbiological model based on a bioreactor-grown biofilm is useful for preliminary in vitro tests of dental materials. In translational terms, an antibacterial nanocomposite coating based on Chitlac-nAg and designed to be applied to methacrylic surfaces may be a promising way to obtain dental materials able to actively prevent secondary caries.

Maternal dietary loads of alpha-tocopherol increase synapse density and glial synaptic coverage in the hippocampus of adult offspring.

An increased intake of the antioxidant α-Tocopherol (vitamin E) is recommended in complicated pregnancies, to prevent free radical damage to mother and fetus. However, the anti-PKC and antimitotic activity of α-Tocopherol raises concerns about its potential effects on brain development. Recently, we found that maternal dietary loads of α-Tocopherol through pregnancy and lactation cause developmental deficit in hippocampal synaptic plasticity in rat offspring. The defect persisted into adulthood, with behavioral alterations in hippocampus-dependent learning. Here, using the same rat model of maternal supplementation, ultrastructural morphometric studies were carried out to provide mechanistic interpretation to such a functional impairment in adult offspring by the occurrence of long-term changes in density and morphological features of hippocampal synapses. Higher density of axo-spinous synapses was found in CA1 stratum radiatum of α-Tocopherol-exposed rats compared to controls, pointing to a reduced synapse pruning. No morphometric changes were found in synaptic ultrastructural features, i.e., perimeter of axon terminals, length of synaptic specializations, extension of bouton-spine contact. Glia-synapse anatomical relationship was also affected. Heavier astrocytic coverage of synapses was observed in Tocopherol-treated offspring, notably surrounding axon terminals; moreover, the percentage of synapses contacted by astrocytic endfeet at bouton-spine interface (tripartite synapses) was increased. These findings indicate that gestational and neonatal exposure to supranutritional tocopherol intake can result in anatomical changes of offspring hippocampus that last through adulthood. These include a surplus of axo-spinous synapses and an aberrant glia-synapse relationship, which may represent the morphological signature of previously described alterations in synaptic plasticity and hippocampus-dependent learning.

Growth factors, their receptor expression and markers for proliferation of endothelial and neoplastic cells in human osteosarcoma.

Osteosarcoma is the most common primary malignant tumour of the bone. Although new therapies continue to be reported, osteosarcoma-related morbidity and mortality remain high. Modern medicine has greatly increased knowledge of the physiopathology of this neoplasm. Novel targets for drug development may be identified through an understanding of the normal molecular processes that are deeply modified in pathological conditions. The aim of the present study is to investigate, by immunohistochemistry, the localisation of different growth factors and of the proliferative marker Ki-67 in order to determine whether these factors are involved in the transformation of osteogenic cells and in the development of human osteosarcoma. We observed a general positivity for NGF - TrKA - NT3 - TrKC - VEGF in the cytoplasm of neoplastic cells and a strong expression for NT4 in the nuclear compartment. TGF-beta was strongly expressed in the extracellular matrix and vascular endothelium. BDNF and TrKB showed a strong immunolabeling in the extracellular matrix. Ki-67/MIB-1 was moderately expressed in the nucleus of neoplastic cells. We believe that these growth factors may be considered potential therapeutic targets in the treatment of osteosarcoma, although proof of this hypothesis requires further investigation.

High-intensity exercise training induces morphological and biochemical changes in skeletal muscles.

IN THE PRESENT STUDY WE INVESTIGATED THE EFFECT OF TWO DIFFERENT EXERCISE PROTOCOLS ON FIBRE COMPOSITION AND METABOLISM OF TWO SPECIFIC MUSCLES OF MICE: the quadriceps and the gastrocnemius. Mice were run daily on a motorized treadmill, at a velocity corresponding to 60% or 90% of the maximal running velocity. Blood lactate and body weight were measured during exercise training. We found that at the end of training the body weight significantly increased in high-intensity exercise mice compared to the control group (P=0.0268), whereas it decreased in low-intensity exercise mice compared to controls (P=0.30). In contrast, the food intake was greater in both trained mice compared to controls (P < 0.0001 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively). These effects were accompanied by a progressive reduction in blood lactate levels at the end of training in both the exercised mice compared with controls (P=0.03 and P < 0.0001 for low-intensity and high-intensity exercise mice, respectively); in particular, blood lactate levels after high-intensity exercise were significantly lower than those measured in low-intensity exercise mice (P=0.0044). Immunoblotting analysis demonstrated that high-intensity exercise training produced a significant increase in the expression of mitochondrial enzymes contained within gastrocnemius and quadriceps muscles. These changes were associated with an increase in the amount of slow fibres in both these muscles of high-intensity exercise mice, as revealed by the counts of slow fibres stained with specific antibodies (P < 0.0001 for the gastrocnemius; P=0.0002 for the quadriceps). Our results demonstrate that high-intensity exercise, in addition to metabolic changes consisting of a decrease in blood lactate and body weight, induces an increase in the mitochondrial enzymes and slow fibres in different skeletal muscles of mice, which indicates an exercise-induced increase in the aerobic metabolism.

Shortened and intensified MJMA: an effective salvage therapy for relapsed and refractory lymphomas and a strong mobilizer of PBSCs.

There is great interest in chemotherapies for relapsed or refractory lymphomas that are both directly effective against the lymphoma and able to mobilize PBSCs for rescue after high-dose chemotherapy (HDC). Twenty-eight patients with relapsed or refractory lymphomas were treated with a shortened, intensified MJMA regimen (mitoxantrone 10 mg/m(2) i.v. day 1, carboplatin 200 mg/m(2) i.v. days 1-2, methylprednisolone 500 mg/m(2) i.v. days 1-3, cytarabine 2000 mg/m(2) i.v. day 3) for six cycles every 21 days. A median of five cycles/patient was administered. Nineteen patients had complete responses, seven partial responses and two no responses. The only remarkable toxicity was hematological. In 18 patients who were candidates for HDC, a mean of 10.45 x 10(6) CD34/kg of patients' body weight was collected (range: 3.70-24.88 x 10(6)/kg). Eleven patients underwent transplantation, which converted two of four partial responses into complete responses. The median follow-up was 49 months. Survival parameters were not related to relapsed/refractory status or to the time from the last chemotherapy, but were related only weakly to the number of prior chemotherapies. Outpatient MJMA is a feasible and very effective salvage chemotherapy per se. The complete response rate is high and it is a powerful PBSC mobilizer.

Complete long-term response to radiotherapy of gastric early-stage marginal zone lymphoma resistant to both anti-Helicobacter pylori antibiotics and chemotherapy.

BACKGROUND: The optimal approach to patients with gastric lymphoma of extranodal mucosa-associated lymphoid tissue (MALT) that resist to anti-Helicobacter pylori (HP) eradication therapy is still to be defined. PATIENTS AND METHODS: From January 1997 to December 2004, we observed 24 patients affected with newly diagnosed early-stage and HP-positive gastric lymphoma of the MALT type. Five of them resisted to oral anti-HP antibiotic regimens and to subsequent one (two patients) or two (three patients) chemotherapy regimens. Age ranged between 51 and 77 years (median 70); three were females. Translocation (11;18) was ascertained in one subject. They were admitted to local radiation therapy with a total dose of 30 Gy. RESULTS: All such resistant patients achieved complete remission after radiotherapy. No relapses were observed after 21, 45, 48, 52, and 67 months of uninterrupted follow-up. Early toxicity was very low and consisted of mild nausea. Late toxicity or secondary malignancy was not recorded so far. CONCLUSIONS: Radiotherapy proved to be effective and safe for early-stage HP-positive gastric extranodal lymphoma of MALT type that is resistant to anti-HP eradication antibiotics and to following chemotherapy. Radiotherapy might be suggested as principal salvage therapy after resistance to HP eradication, instead of chemotherapy.

ABVD plus radiotherapy versus EVE plus radiotherapy in unfavorable stage IA and IIA Hodgkin's lymphoma: results from an Intergruppo Italiano Linfomi randomized study.

BACKGROUND: In 1997, the Intergruppo Italiano Linfomi started a randomized trial to evaluate, in unfavorable stage IA and IIA Hodgkin's lymphoma (HL) patients, the efficacy and toxicity of the low toxic epirubicin, vinblastine and etoposide (EVE) regimen followed by involved field radiotherapy in comparison to the gold standard doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) regimen followed by the same radiotherapy program. PATIENTS AND METHODS: Patients should be younger than 65 years with unfavorable stage IA and IIA HL (i.e. stage IA or IIA with bulky disease and/or subdiaphragmatic disease, erythrocyte sedimentation rate higher than 40, extranodal (E) involvement, hilar involvement and more than three involved lymph node areas). RESULTS: Ninety-two patients were allocated to the ABVD arm and 89 to the EVE arm. Complete remission (CR) rates at the end of treatment program [chemotherapy (CT) + RT] were 93% and 92% for ABVD and EVE arms, respectively (P = NS). The 5-year relapse-free survival (RFS) rate was 95% for ABVD and 78% for EVE (P < 0.05). As a consequence of the different relapse rate, the 5-year failure-free survival (FFS) rate was significantly better for ABVD (90%) than for EVE (73%) arm (P < 0.05). No differences in terms of overall survival (OS) were observed for the two study arms. CONCLUSIONS: In unfavorable stage IA and IIA HL patients, no differences were observed between ABVD and EVE arms in terms of CR rate and OS. EVE CT, however, was significantly worse than ABVD in terms of RFS and FFS and cannot be recommended as initial treatment for HL.

New insights into the role of age and carcinoembryonic antigen in the prognosis of colorectal cancer.

The aim of this study was to verify through relative survival (an estimate of cancer-specific survival) the true prognostic factors of colorectal cancer. The study involved 506 patients who underwent locally radical resection. All the clinical, histological and laboratory parameters were prognostically analysed for both overall and relative survival. This latter was calculated from the expected survival of the general population with identical age, sex and calendar years of observation. Univariate and multivariate analyses were applied to the proportional hazards model. Liver metastases, age, lymph node involvement and depth of bowel wall involvement were independent prognosticators of both overall and relative survival, whereas carcinoembryonic antigen (CEA) was predictive only of relative survival. Increasing age was unfavourably related to overall survival, but mildly protective with regard to relative survival. Three out of the five prognostic factors identified are the cornerstones of the current staging systems, and were confirmed as adequate by the analysis of relative survival. The results regarding age explain the conflicting findings so far obtained from studies considering overall survival only and advise against the adoption of absolute age limits in therapeutic protocols. Moreover, the prechemotherapy CEA level showed a high clinical value.

The role of dose size in a chemotherapy regimen (ProMECE-CytaBOM) for the first-line treatment of large B-cell lymphomas: a randomized trial by the Gruppo Italiano Studio Linfomi (GISL).

BACKGROUND: It is still unclear the actual contribute of dose intensity (DI), dose size (DS) and dose density (DD) in the conventional chemotherapy of large, B-cell non-Hodgkin lymphomas. METHODS: A prospective, randomized trial compared the cyclic schedule of ProMECE-CytaBOM chemotherapy (cyc-PC, 6 cycles) with a modified version of it, which administered the same drugs sequentially (seq-PC), with the same planned cumulative DI and an 83% DD, within the same time frame (113 days), but with three times higher DS of all the drugs except vincristine. RESULTS: Fifty-six patients received cyc-PC and 52 seq-PC. The actual mean cumulative DI was 0.79 +/- 0.15 with cyc-PC, 0.78 +/- 0.17 with seq-PC. Response was complete in 59% and 52%, partial in 20% and 21%, null in 5% and 6%, respectively. There were four toxic deaths (two per arm). Relapses occurred in 36% and 37%, respectively. Toxicity was similar in both arms. Overall, failure-free, progression-free and disease-free survival (median follow-up: 54 months) were statistically indifferent. CONCLUSIONS: The very similar DI actually delivered in both arm seems to be the main common determinant of the indifferent results recorded. Increasing DS--at least within the limits clinically attainable without stem cell rescue--does not improve results.

The role of high-dose therapy and autologous stem cell transplantation in patients with primary refractory Hodgkin's lymphoma: a report from the Gruppo Italiano per lo Studio dei Linfomi (GISL).

GISL recently conducted an exhaustive survey of 1078 patients with Hodgkin's Lymphoma (HL) enrolled between 1988 and 2002 in different prospective trials. Treatment failure was observed in 82 out of 1078 patients; of these 82 patients with refractory HL, complete information was available for 72, who form the evaluable population of the present study. After the initial therapy failure, 51 patients were treated with conventional salvage chemotherapy (CC) (n = 24) or high-dose chemotherapy (HDC) (n = 27); 4-year overall survival (OS) was 81% in the HDC group versus 38% in the CC group (P = 0.019). The remaining 21 patients had rapidly progressive disease and died. After a median follow-up of 2.8 years, the projected OS for all 72 patients is 58 and 49% at 3 and 5 years, respectively. Age <45 years, the absence of systemic symptoms and a PS <1 predicted a significantly longer OS. Interestingly, the majority of patients with two or three negative prognostic factors did not receive potentially curative therapy. In conclusion, HDC seems to be a reasonable option for selected patients with refractory HL, although the majority of them did not receive a transplant. Finally, patients with a high-risk score had little chance of receiving potentially curative treatment.

Rhodiola rosea as antioxidant in red blood cells: ultrastructural and hemolytic behaviour.

Rhodiola rosea L. (Crassulaceae) is a plant that lives at high altitude in Europe and Asia, widely used for its high capacity to increase the organism resistance to different stress conditions. Although a few international literature supports these effects, today R. rosea has become a common component of many dietary supplements also in the Western world. The aim of the present study was to investigate the effect of the R. rosea roots aqueous extract on in vitro human erythrocytes exposed to hypochlorous acid (HOCl)-oxidative stress. Several damages occur in human erythrocytes exposed in vitro to HOCl, among these membrane protein and lipid modifications, shifting from the discocyte shape to the echinocyte one, and determining lysis ultimately. Therefore, in the present work, the evaluation of the antioxidant capacity of the Rhodiola extract has been carried out by means of scanning electron microscopy and of hemolytic behaviour on human erythrocytes exposed to HOCl in the presence of increasing doses of the aqueous extract in different experimental environments (co-incubation and subsequent incubations). The results obtained are consistent with a significant protection of the extract in presence of the oxidative agent, but a cautionary note emerges from the analysis of the data related to the cell exposition to the plant extract in the absence of any induced oxidative stress. In fact, the addition to erythrocyte of high doses of R. rosea extract always determines severe alterations of the cell shape.

Evaluation of leukocyte stabilisation in TransFix-treated blood samples by flow cytometry and transmission electron microscopy.

In this report, we have evaluated the effects of a TransFix-based stabilisation technique on leukocyte scatter characteristics, immunophenotyping, membrane permeability, absolute cell counting and morphology to extend previously reported flow cytometric data focused on the lymphocyte population. We show that scatter characteristics, immunophenotyping and absolute cell counting are well preserved, particularly in the lymphocyte population. Nevertheless, a general increase in membrane permeability, evaluated by propidium iodide (PI) uptake, was observed in TransFix-treated leukocyte subsets. Ultrastructural observations show selective morphological preservation (up to 10 days of storage) of lymphocytes and, to a lesser extent, of monocytes. In contrast, granulocytes have necrosis-like features, although the plasma membrane seems well preserved. Therefore, electron microscopy observations reflect modifications induced in different cell populations as evidenced by flow cytometry (FC). The data indicate that this short-term stabilisation method is particularly suitable for the analysis of human lymphocytes and it is a good procedure for quality control programmes for inter- and intra-laboratory performance evaluation; good results are obtained with respect to antigen definition and absolute cell counting procedures. Any apoptotic pathways in leukocyte subsets are blocked for at least 10 days.

Radiological evidence of anatomical variation of the inferior vena cava: report of two cases.

The inferior vena cava (IVC) is a retroperitoneal key structure whose location and integrity must be checked in every scan. A number of studies are reported in the literature concerning congenital variations of the inferior vena cava. Anatomical variations of this main venous trunk are relatively infrequent clinical findings during surgery or diagnostic procedures in patients without symptoms such as an aberrant venous drainage or abdominal pain. Among the other imaging techniques, computerized tomography is a non-invasive, effective technique for diagnosing diseases of the retroperitoneal space and, particularly, for detecting anomalies of the main vessels, such as the aorta or IVC, in asymptomatic patients. We present two cases of IVC variation as an incidental finding in patients studied by means of CT scan for the gradation of kidney carcinoma and pancreatic cancer respectively. Two different configurations of the system of the IVC (agenesis of the IVC with hypertrophy of the azygos vein and a double IVC respectively) were found in our cases. The embryological development of the IVC system is discussed, bearing in mind that knowledge of the different variations is important in order to avoid major surgical complications.

Immunocytochemical analysis of dentin: a double-labeling technique.

Immunocytochemical analysis is a fundamental and selective technique for identifying different molecular components of human dental structure. The hypothesis tested here is that the application of different etching solutions on dentin does not hinder collagen fibrils and proteoglycans from maintaining their immunochemical antigenicity. Human dentin disks were treated with 0.5M of EDTA, citric acid, maleic acid, or phosphoric acid (for 15 or 30 s). A double-immunolabeling technique was performed to identify, simultaneously, collagen fibrils and chondroitin sulfate. The use of different acids resulted in different degrees of labeling. Maleic and citric acids revealed a diffuse and intense labeling for both collagen fibrils and proteoglycans. The use of phosphoric acid on dentin showed a massive coagulation of the proteoglycans (15 s) or very low labeling (30 s). These data clarify that the use of acids on dentin components is able to modify their antigenicity. Moreover, the double-labeling immunocytochemical technique allows understanding of the spatial relationships between the collagen fibrils and proteoglycans of the dentin matrix.

Human articular chondrocytes immortalized by HPV-16 E6 and E7 genes: Maintenance of differentiated phenotype under defined culture conditions.

OBJECTIVE: To establish an immortalized normal human articular chondrocyte line which could be useful for a better understanding of cell molecular mechanisms relevant for the development of new therapeutic approaches in rheumatic diseases. DESIGN: Chondrocytes from human adult articular healthy cartilage were transfected in primary culture with a plasmid containing two human papilloma virus type 16 (HPV-16) early function genes: E6 and E7, using the highly efficient cationic liposome-mediated (lipofection) procedure. The transfection was verified by reverse transcriptase-polymerase chain reaction analysis of E7 mRNA and by immunofluorence localization of the E7 protein in the cell cytoplasm. The established chondrocyte cell line was examined in monolayer and in two culture conditions that were described to re-induce differentiated characteristics: culturing in a serum-free defined medium supplemented with an insulin-containing serum substitute and seeding on a hyaluronan-based non-woven structured biomaterial. The expression of markers characteristic of cartilage was shown in the mRNA by reverse transcriptase-polymerase chain reaction. Immunohistological staining and Western blotting analysis were performed to evaluate type II collagen synthesis. Proteoglycans deposition was detected by Alcian Blue staining. A Field Emission In Lens Scanning Microscopy was used to look at the morphology of the immortalized cells at very high magnification. RESULTS: Normal human articular chondrocytes were efficiently transfected leading to the establishment of an immortalized cell line as confirmed by HPV-16 E7 mRNA and protein detection. These cells were able to re-express type II collagen both at mRNA and protein levels under the two defined cultured conditions we used, still maintaining type I collagen expression. Collagen IX mRNA was present only in early primary culture while collagen type X and aggrecan transcripts were always detected. Alcian Blue staining showed a proteoglycan-rich matrix production. The ultrastructural analysis of the immortalized cells revealed that their morphology strictly resembled that of normal chondrocytes. CONCLUSIONS: The cell line that we obtained may be a useful tool for increasing our knowledge of the genetic and biochemical events involved in the processes of cartilage growth and differentiation. Moreover, it appears to be a suitable model for pharmacological and toxicological studies related to rheumatic diseases relevant to humans.