Effect of simulated pulpal pressure on dentin permeability and adhesion of self-etch adhesives

OBJECTIVES

Dentin bonds made with one-bottle etch-and-rinse and self-etch adhesives are affected by the formation of interfacial blisters, porosities and deterioration. The first objective of this study was to evaluate the fluid flow through resin-dentin interfaces created by self-etching adhesives applied to deep dentin using a replica technique and by directly measuring dentin permeability (P). The second objective was to examine the effect of intrapulpal pressure on the microtensile bond strength of these adhesives.

METHODS

A fluid-transport model was used to measure the fluid permeability (%P) through different adhesives. Impressions of bonded dentin were taken with a polyvinylsiloxane impression material to monitor fluid transudation from the surface of the adhesive. Positive replicas were fabricated for SEM examination. Two groups of resin-bonded specimens (pulpal pressure versus no pulpal pressure) were created for microtensile bond strength evaluation. Adhesive application was performed under 0 cm H(2)O. Pulpal pressure group was submitted to 20 cm H(2)O of pulpal pressure during build-up procedures.

RESULTS

Clearfil Protect Bond exhibited the lowest permeability and fewest numbers of fluid droplets over the surface of the bonded dentin. G-Bond and Clearfil-S3 Bond were more permeable than Clearfil Protect Bond. One Up Bond F was the most permeable adhesive. A highly significant correlation was observed between the relative permeability of these adhesives (%P) and the number of fluid droplets on the adhesive surfaces. The application of pulpal pressure significantly reduced bond strength.

SIGNIFICANCE

Resin-dentin bonds created by contemporary self-etch adhesives are susceptible to fluid permeation induced by pulpal pressure. HEMA-based adhesives showed the largest reductions in bond strengths after pulpal pressure application.

Rb family proteins as modulators of gene expression and new aspects regarding the interaction with chromatin remodeling enzymes

The pRb family proteins (pRb1/105, p107, pRb2/p130), collectively referred to as pocket proteins, are believed to function primarily as regulators of the mammalian cell cycle progression, and suppressors of cellular growth and proliferation. In addition, different studies suggest that these pocket proteins are also involved in development and differentiation of various tissues. Several lines of evidence indicate that generally pRb-family proteins function through their effect on the transcription of E2F-regulated genes. In fact, each of Rb family proteins binds to distinct members of the E2F transcription factors, which regulate the expression of genes whose protein products are necessary for cell proliferation and to drive cell-cycle progression. Nevertheless, pocket proteins can affect the G1/S transition through E2F-independent mechanisms. More recently, a broad range of evidences indicate that pRb-family proteins associate with a wide variety of transcription factors and chromatin remodeling enzymes forming transcriptional repressor complexes that control gene expression. This review focuses on the complex regulatory mechanisms by which pRb-family proteins tell genes when to switch on and off.

Identification of a molecular signature predictive of sensitivity to differentiation induction in acute myeloid leukemia

Acute myeloid leukemia (AML) blasts are immature committed myeloid cells unable to spontaneously undergo terminal maturation, and characterized by heterogeneous sensitivity to natural differentiation inducers. Here, we show a molecular signature predicting the resistance or sensitivity of six myeloid cell lines to differentiation induced in vitro with retinoic acid or vitamin D. The identified signature was further validated by TaqMan assay for the prediction of response to an in vitro differentiation assay performed on 28 freshly isolated AML blast populations. The TaqMan assay successfully predicts the in vitro resistance or responsiveness of AML blasts to differentiation inducers. Furthermore, performing a meta-analysis of publicly available microarray data sets, we also show the accuracy of our prediction on known phenotypes and suggest that our signature could become useful for the identification of patients eligible for new therapeutic strategies.

MATILDE regimen followed by radiotherapy is an active strategy against primary CNS lymphomas

The authors assessed MATILDE chemotherapy followed by response-tailored radiation therapy in 41 patients aged 70 years or younger with primary CNS lymphoma in a Phase II trial. With response rates of 76% after MATILDE and 83% after chemotherapy with or without radiation therapy, this was an active strategy, particularly in low- to intermediate-risk patients (International Extranodal Lymphoma Study Group [IELSG] score). Myelosuppression was the dose-limiting toxicity, with 9.5% of lethal complications. After a median follow-up of 49 months, a plateau in the survival curve (5-year overall survival: 41 +/- 7%) was obtained.

Nuclear and cytoplasmic interaction of pRb2/p130 and ER-β in MCF-7 breast cancer cells

Estrogens exhibit important biological functions and influence several pathological processes of hormone-dependent diseases. The biological actions of estrogens require their interaction with two estrogen receptors (ER-alpha and ER-beta), which are ligand-dependent transcription factors. ER-alpha and ER-beta exhibit distinct tissue expression patterns as well as show different patterns of gene regulation. In addition, it has been suggested that ER-beta works as a counter partner of ER-alpha through inhibition of the transactivating functions of ER-alpha. For instance, ER-beta seems to play a different role in breast tumorigenesis than ER-alpha, as ER-beta decreased expression in breast cancer has been correlated with bad prognosis. Biological activities of ER-alpha and ER-beta could be controlled by a number of interacting proteins such as activators/inhibitors, ligand binding and kinases. We have previously reported that pRb2/p130, retinoblastoma related protein, could be involved in the silencing of ER-alpha gene during breast tumorigenesis. Here, we report that ER-beta and pRb2/p130 proteins co-immunoprecipitate in both nucleus and cytoplasm of MCF-7 breast cancer cells. Our hypothesis is that the interaction of pRb2/130 with ER-beta may have a functional significance in regulating ER-beta activity.

Virally mediated MafB transduction induces the monocyte commitment of human CD34+ hematopoietic stem/progenitor cells

Upregulation of specific transcription factors is a generally accepted mechanism to explain the commitment of hematopoietic stem cells along precise maturation lineages. Based on this premise, transduction of primary hematopoietic stem/progenitor cells with viral vectors containing the investigated transcription factors appears as a suitable experimental model to identify such regulators. Although MafB transcription factor is believed to play a role in the regulation of monocytic commitment, no demonstration is, to date, available supporting this function in normal human hematopoiesis. To address this issue, we retrovirally transduced cord blood CD34+ hematopoietic progenitors with a MafB cDNA. Immunophenotypic and morphological analysis of transduced cells demonstrated the induction of a remarkable monomacrophage differentiation. Microarray analysis confirmed these findings and disclosed the upregulation of macrophage-related transcription factors belonging to the AP-1, MAF, PPAR and MiT families. Altogether our data allow to conclude that MafB is a key regulator of human monocytopoiesis.

Cytoplasmic and nuclear interaction between Rb family proteins and PAI-2: a physiological crosstalk in human corneal and conjunctival epithelial cells

Extracellular plasminogen activator inhibitor type-2 (PAI-2) is a potent inhibitor of urokinase-type plasminogen activator (u-PA) and also acts as a multifunctional protein. However, the biological activity of intracellular PAI-2, as well as its intracellular targets, until now remain an enigma. Here, we show that pRb2/p130 and Rb1/p105, but not p107, interact with PAI-2 in both the cytoplasm and nucleus of normal primary human corneal and conjunctival epithelial cells. We provided the first in vivo evidence that a specific fragment of the PAI-2 promoter is bound simultaneously by pRb2/ p130, PAI-2, E2F5, histone deacetylase 1 (HDAC1), DNA methyltransferase 1 (DNMT1), and histone methyltransferase (SUV39H1), in normal primary human corneal epithelial cells, and by pRb2/p130, PAI-2, E2F5, HDAC1, and DNMT1, in normal primary human conjunctiva epithelial cells. Our results strongly indicate a physiological interaction between pRb family members and PAI-2, suggesting the hypothesis that pRb2/p130 and PAI-2 may cooperate in modulating PAI-2 gene expression by chromatin remodeling, in normal corneal and conjunctival cells.

Correlation between differentiation plasticity and mRNA expression profiling of CD34+-derived CD14− and CD14+ human normal myeloid precursors

In spite of their apparently restricted differentiation potentiality, hematopoietic precursors are plastic cells able to trans-differentiate from a maturation lineage to another. To better characterize this differentiation plasticity, we purified CD14- and CD14+ myeloid precursors generated by 'in vitro' culture of human CD34+ hematopoietic progenitors. Morphological analysis of the investigated cell populations indicated that, as expected, they consisted of granulocyte and monocyte precursors, respectively. Treatment with differentiation inducers revealed that CD14- cells were bipotent granulo-monocyte precursors, while CD14+ cells appeared univocally committed to a terminal macrophage maturation. Flow cytometry analysis demonstrated that the conversion of granulocyte precursors to the mono-macrophage maturation lineage occurs through a differentiation transition in which the granulocyte-related myeloperoxidase enzyme and the monocyte-specific CD14 antigen are co-expressed. Expression profiling evidenced that the observed trans-differentiation process was accompanied by a remarkable upregulation of the monocyte-related MafB transcription factor.

The regulation of ER-α transcription by pRb2/p130 in breast cancer

Breast carcinoma is the most common form of neoplasia in women of the Western world, and the mortality from this disease in women is second only to that of lung cancer, with a means incidence of 10%. Although, several studies have indicated that the development of this fairly heterogeneous disease depends on a great many environmental, socio-economic, hormonal and genetic factors, the pathogenesis of breast cancer remains poorly understood. ER-alpha (estrogen-receptor alpha) and its ligand (17beta-estradiol) play a crucial role in normal breast development and have also been linked to mammary carcinogenesis and clinical outcome in breast cancer patients. The estrogen signaling regulates the growth of some breast tumors, and antiestrogen therapies can effectively block this growth signaling resulting in tumor suppression. However, most tumors eventually develop antiestrogen resistance, and antiestrogen are mostly ineffective in patience with advanced disease. Although several studies have been proposed that epigenetic events could be involved in ER-alpha silencing the mechanisms regulating ER-alpha transcription are poorly understood. Our studies suggested that pRb2/p130-complexes bind to the ER-alpha promoter and could be involved in the transcriptional regulation of the ER-alpha gene by altering chromatin structure and DNA methylation pattern.

Combined administration of alpha-erythropoietin and filgrastim can improve the outcome and cost balance of autologous stem cell transplantation in patients with lymphoproliferative disorders

We compared the use of G-CSF plus EPO in a group of 32 multiple myeloma and lymphoma patients with historical controls receiving G-CSF alone. Haemopoietic reconstitution was significantly faster in patients receiving G-CSF+EPO (group B), with a median time of 10 days to achieve an ANC count >0.5 x 10(9)/l, compared to 11 days in the historical group (A). The median duration of severe neutropenia (ANC count <100/ml) was significantly shorter in group B compared to group A; platelet counts >20 x 10(9) and >50 x 10(9)/l were achieved at days + 13 and + 17, respectively in group B, compared to days + 14 and + 24, respectively, in group A (P = 0.015, 0.002) patients. The transfusion requirement was reduced in group B, with 0 (0-6) RBC units and 1 (0-5) platelet unit transfused in group B vs 2 RBC (0-9) and 2 platelet units (0-8) in group A. Median days of fever, antibiotic therapy and hospital stay were reduced in group B (9.5 days vs 22). The mean cost of autotransplantation per group A patient was 23,988 Euro, compared with 18,394 Euro for a group B patient. Our study suggests that the EPO + G-CSF combination not only accelerates engraftment kinetics, but can also improve the clinical course of ASCT.

[Exposure to water disinfection by-products and adverse pregnancy outcomes: results of a case-control study carried out in Modena (Italy)]

Chlorination By Products (CBPs) in drinking water have been associated with an increased risk of adverse pregnancy outcomes, such as small term birth (STB) and preterm delivery. Up to date epidemiological evidence is weakened by a generally inaccurate exposure assessment, often at an ecological level: in this study the exposure is evaluated at the individual level. A case control study with incident cases was performed in Modena between October 1999-September 2000. 332 subjects were enrolled: 93 preterm births (26th-37th week of pregnancy), 73 STB (from 38th week, and weight less than the lowest 10th percentile) and 166 controls. Exposure was assessed both by applying a questionnaire on personal habits and by personal water sampling directly at subjects' home. THMs were analysed in all samples, chlorite and chlorate in water samples treated with chlorine dioxide. Subjects usually drinking tap water were few (5.2%): most of them were living in areas supplied by water treated with chlorine dioxide (87%). Levels of THMs were low (mean: 0.73 microgram/l), while chlorite and chlorate concentrations were relatively high (mean: 217.8 microgram/l for chlorites and 95.2 microgram/l for chlorates). Preterm birth did not show any significant association with CBPs, while STB appeared significantly associated, after adjusting for many potential confounders, with CBPs induced by chlorine dioxide treatment, especially with levels of chlorate higher than 200 microgram/l (OR: 4.7; 95%CI: 1.15-19.72). The association between STB and chlorate must be investigated further as the number of water utilities applying chlorine dioxide as disinfection treatment is increasing.

Treatment of the cancer anorexia-cachexia syndrome: a critical reappraisal

Cancer anorexia-cachexia syndrome (CACS) is a combination of anorexia, tissue wasting, weight loss and poor performance status. Some CACS symptoms are due to a macrophage production of TNF and IL-1, while the metabolic effects are mainly explained by the release of IL-6 from tumor cells. Clinical treatment of CACS involves progestational agents (medroxyprogesterone acetate, MPA, megestrol acetate, MA) for long term treatment. The use of prokinetic agents (like metoclopramide) is recommended, especially if patients need concomitant opioid treatment for pain; if otherwise indicated, corticosteroids are useful for short periods. The administration of artificial nutrition should be individualized following the clinical condition of the patient and possibly taking into account the wishes of the patient. The practical evaluation criteria of the drugs employed for CACS are based on weight increase and appetite stimulation. Hence, a new approach to the mechanism of action of MPA, MA and of other agents is urgently needed.

Gene expression profile of Vitamin D3 treated HL60 cells shows an incomplete molecular phenotypic conversion to monocytes

By high density oligonucleotide microarrays we have studied the expression profile of proliferating and VD treated HL60 cells and the molecular phenotype of VD monocytes and that of CD14+ peripheral monocytes has been compared. The results indicate that important changes in functional categories of the differentially expressed genes underlie the differentiation transition from myeloblasts to monocytes. This differential gene expression pattern leads to an increased expression of mRNAs involved in surface and external activities since many of the VD induced genes belong to ligand binding, receptors, cell surface antigens, defense/immunity and adhesion molecules functional categories. The results also indicate that the molecular phenotypes of monocytes and VD induced cells diverge for a small but significant set of defense related genes. Particularly, class II MHC genes are not expressed in these cells. Furthermore, the high levels of expression of these genes induced by serum treatment of monocytes are decreased by VD.

Very low toxicity and good quality of life in 48 elderly patients autotransplanted for hematological malignancies: a single center experience

Between May 1994 and May 2000, we autotransplanted 48 consecutive patients, 21 females and 27 males aged over 60 years (range: 60-78, median: 63). Sixteen patients had multiple myeloma (MM), 14 high-grade non-Hodgkin's lymphoma (HGNHL), six low-grade non-Hodgkin's lymphoma (LGNHL), nine acute myeloid leukemia (AML), one chronic lymphocytic leukemia (CLL), one Hodgkin's disease (HD) and one breast cancer; the performance status (WHO) was 0-1. Seventeen patients were in 1st CR (35.4%) and one in 2nd CR (2.1%), 25 in PR (52.1%), while five patients had been transplanted with progressive disease (10.4%); seven patients with MM received a double transplant. Patients received high-dose therapy including melphalan alone (13) or associated with other drugs (26), busulfan-cyclophosphamide (three), BEAM (11) and TBI (two). All patients took a median of 11 (range: 8-25) days to reach neutrophils >500/microl, 13 (range: 9-83) days to reach platelets > 20,000/microl and 17 (range: 11-83) days to reach platelets > 50,000/microl. Hematological toxicity, hospital stay and supportive care did not differ from those of a cohort of younger patients. At present, 31 patients are alive (14 in CR, five in PR, five in PD and seven in relapse) and 16 died from PD at a median follow-up of 37 months (1-67). Only one patient died from transplant-related toxicity. Quality of life, evaluated using a QLQ-C30 questionnaire in 25 patients at day +90, was good. In our experience PBPC mobilization and transplantation is feasible in patients aged > or = 60 years and the toxicity of this procedure is acceptable, with an early transplant-related mortality of 1.8%; therefore patients with hematological malignancies potentially curable with high-dose therapy (HDT) should also be candidates for HDT.

A predictive model of varicella-zoster virus infection after autologous peripheral blood progenitor cell transplantation

Varicella-zoster virus (VZV) frequently causes severe infections in patients who have undergone bone marrow transplantation. The frequency of, characteristics of, and risk factors for this infection were studied in 164 patients undergoing autologous peripheral blood progenitor cell transplantation (PBPCT). Twenty-six patients (15.8%) developed VZV infection, and the actuarial risk was 10% at 1 year. No patient had visceral dissemination or died because of VZV, although one-third of the patients developed postherpetic neuralgia. By multivariate analysis, a CD4(+) lymphocyte count of <200 cells/microL (P<.0001; odds ratio [OR], 2.0) and a CD8(+) lymphocyte count of <800 cells/microL (P=.0073; OR, 2.0) at day 30 after transplantation were factors associated with VZV infection. Patients with both these adverse factors had an actuarial risk of VZV of 48% at 1 year. Patients with deficiency in both CD4(+) and CD8(+) lymphocytes are at high risk of VZV infection. These patients should be considered as candidates for preventive therapy, but whether for antiviral therapy or vaccination remains to be investigated.

A functionally active RARalpha nuclear receptor is expressed in retinoic acid non responsive early myeloblastic cell lines

Although all-trans retinoic acid (ATRA) can restore the differentiation capacity of leukemic promyelocytes, early leukemic myeloblasts are conversely not responsive to ATRA induced granulocytic differentiation. To assess whether this resistance to ATRA is related to an impaired function of the Retinoic Acid Receptor alpha (RARalpha), we performed an analysis of RARalpha expression and transactivation activity, in several myeloid leukemic cell lines, representative of different types of spontaneous acute myeloid leukemias. Our results indicate that a functionally active RARalpha nuclear receptor is expressed in all the analyzed cell lines, regardless of their differentiation capacity following exposure to ATRA. The observation that ATRA treatment is able to induce the expression of retinoic acid target genes, in late- but not in early-myeloblastic leukemic cells, raises the possibility that the differentiation block of these cells is achieved through a chromatin mediated mechanism. Acetylation is apparently not involved in this process, since the histone deacetylase inhibitor trichostatin A, is not able to restore the differentiation capacity of early leukemic myeloblasts. Further investigation is needed to clarify whether myeloid transcription factors, distinct to RARalpha, play a role in the resistance of these cells to ATRA treatment.

Amifostine can reduce mucosal damage after high-dose melphalan conditioning for peripheral blood progenitor cellautotransplant: a retrospective study

Amifostine (WR-2721; Ethyol) is a well-known cytoprotector, but a possible role in preventing extrahaematological toxicity after high-dose therapy (HDT) has never been investigated. We compared two historical groups of patients who either received (group A, n = 35) or did not receive (group B, n = 33) amifostine (740 mg/m2) before high-dose (HD) melphalan, followed by autologous infusion of peripheral blood progenitor cells (PBPCs). Amifostine was well tolerated at this dose level. Emesis grade 1-2 was the most important side-effect, but the interruption of infusion was never required. The incidence and median duration of severe mucositis (grade 3-4) was 21% and 0 d (range 0-11 d) in group A and 53% and 7 d (range 0-11 d) in group B. The duration of analgesic therapy was also significantly lower in group A (0 d; range 0-12) than in group B (6 d, range 0-20) (P = 0.0001). Severe diarrhoea (3% vs. 25%; P = 0.01) and emesis (9% vs. 34%; P = 0.01) were also reduced in group A in comparison with group B. No differences were observed between the two groups for haematological recovery. This retrospective study strongly suggests that amifostine can reduce severe mucositis and the use of analgesic drugs in this setting. A randomized study is warranted to confirm these preliminary results.

Infectious complications after autologous peripheral blood progenitor cell transplantation followed by G-CSF

Infectious complications after autologous peripheral blood progenitor cell transplantation (PBPCT) have been reported in a few studies including small patient numbers. The present study was performed to assess the incidence, types, outcome and factors affecting early and late infections in 150 patients aged 18 to 68 years (median 46.5) who underwent high-dose therapy, with G-CSF. Patients were kept in reverse isolation rooms and received antimicrobial chemoprophylaxis with oral quinolone and fluconazole. One hundred and fifteen patients (76.7%) developed fever (median 3 days, range 1-29); 20 patients (55.5%) had Gram-positive and 13 (36. 2%) Gram-negative bacterial infections. There were no fungal infections or infection-related deaths. Mucositis grade II-IV (P = 0. 0001; odds ratio 3.4) and >5 days on ANC <100/microl (P = 0.0001; odds ratio 2.3) correlated with development of infection. Only days with ANC <100/microl affected infection outcome (P = 0.0024) whereas the antibiotic regimen did not. After day +30 there were four cases of bacterial pneumonitis (2.7%), one case of fatal CMV pneumonia (0. 8%) and 20 of localized VZV infection (13.3%). Reduction of neutropenia duration with PBPCT and G-CSF is not enough to prevent early infectious complications since only a few days of severe neutropenia and mucositis are related to development of early infections. However, no infection-related deaths were seen. Although Gram-positive organisms were the major cause of bacteremia, a glycopeptide in the empirical antibiotic regimen did not affect infection outcome. In PBPCT recipients, early and late opportunistic infections were notably absent, which was at variance with what was seen with bone marrow recipients. Efforts should be made to prevent mucositis and neutropenia and identify new strategies of antibacterial prophylaxis.

Selection and transplantation of autologous CD34+ B-lineage negative cells in advanced-phase multiple myeloma patients: a pilot study

The feasibility of sequential positive and negative selection of mobilized CD34+ B-lineage negative cells to achieve tumour-free autografts in multiple myeloma (MM) patients was evaluated. Peripheral blood stem cells (PBSC) of 14 patients with advanced disease were mobilized. CD34+ cells were enriched in 12 of the patients by the avidin-biotin immunoabsorption technique. Subsequently, CD10+, CD19+, CD20+ and CD56+ cells (B-lin cells) were removed by immunomagnetic depletion. Minimal residual disease (MRD) was detected by flow cytometry and PCR-based molecular analysis of the patient specific IgH complementary-determining region III (CDRIII). Positive selection of stem cells produced a median recovery of 54.7% of the initial content of CD34+ cells (median purity 71.9%). Negative depletion of B-lineage cells reduced the number of CD34+ cells to 33.3% of the baseline value (median purity 72.7%). However, long-term culture assays showed the recovery of >60% of primitive haemopoietic progenitor cells after depletion of the B-lineage-positive cells. All evaluable patients had detectable disease in PBSC collections. The first step of positive selection of CD34+ cells resulted in >2 logs of tumour cell purging. However, molecular assessment showed the persistence of the disease in 6/7 cases. Immunofluorescence analysis demonstrated 1 additional log of B-cell purging by negative depletion. More importantly, molecular evaluation of IgH CDRIII region showed the disappearance of myeloma cells in 6/7 patients. 12 patients received a median of 3.9 x 106 CD34+ B-lin- cells/kg after conditioning with high-dose melphalan and showed a rapid reconstitution of haemopoiesis. These results were similar to two similar cohorts of patients who received either unmanipulated PBSC or positively selected CD34+ cells after the same conditioning regimen. Severe extrahaematological toxicity was limited to mucositis; no late infections were observed. We concluded that autotransplantation of purified CD34+ B-lin- cells was associated with a rapid and sustained recovery of haemopoiesis and low peritransplant morbidity. Sequential positive and negative enrichment of stem cells reduced tumour cell contamination in B-cell malignancies below the lower limit of detection of molecular analysis.