Effect of high irradiance and short exposure times on the depth of cure of six bulk-fill resin composites.

This study examined the effect of high irradiance and short exposure times on the depth of cure of six resin-based composites (RBCs). Bluephase PowerCure and the Valo X light-curing units (LCUs) were used to photocure bulk-fill RBCs for their recommended exposure times: Admira Fusion x-tra (AFX/20s), Aura Bulk Fill (ABF/20s), Filtek One Bulk Fill (FOB/20s), Opus Bulk Fill APS (OBF/30s), Tetric EvoCeram Bulk Fill (TEC/10s) and Tetric PowerFill (TPF/10s). In addition, all bulk-fill RBCs were tested for depth of cure with one short 3 s exposure time from the Bluephase PowerCure or the Valo X in the Xtra Power mode. The RBCs (n = 10 per RBC) were inserted into a 4 mm diameter metal mold and covered by a polyester strip before being photocured. After 24 h of storage, uncured RBC was scraped away to determine the depth of cure of the RBCs. None of the RBCs achieved a 4 mm depth of cure. The depth of cure of TEC and TPF was unaffected by the exposure times (recommended or short) when using the Valo X. The depth of cure of AFX/20s, AFX/Xtra Power, ABF/Xtra Power, FOB/Xtra Power, and OBF/30s RBCs was greater when using Valo X compared to the Bluephase PowerCure. It was concluded that short exposure times can reduce depth of cure and should only be used for some RBCs.

Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Color alterations, flexural strength, and microhardness of 3D printed resins for fixed provisional restoration using different post-curing times.

OBJECTIVES: To evaluate the effect of post-curing times on the color change, flexural strength (FS), modulus (FM) and microhardness at different depths of four 3D printed resins. MATERIALS AND METHODS: A characterization of the light emitted by 3D-resin post-curing unit (Wash and Cure 2.0, Anycubic) was performed. The tested 3D printed resins were Cosmos Temp3D (COS), SmartPrint BioTemp (SM) Resilab3D Temp (RES) and Prizma3D BioProv (PRI) were evaluated under five different post-curing conditions (no post-curing or 5-, 10-, 15, and 20 min of post-curing). For color change analysis, 10 mm diameter x 1 mm thick discs (n = 7) were printed, and the luminosity, color and translucency were measured before post-curing as control, and repeatedly after 5 min cycles of post-curing until a total of 20 min was reached for ΔE00 [CIED2000 (1:1:1)] calculation. For FS and FM, 25 × 2×2 mm (n = 10, for each post-curing time) 3D printed bars were subjected to a 3-point being test. Knoop microhardness (KHN) was measured transversally on 5 × 5×5 mm blocks (n = 10, for each post-curing time). Color results were analyzed by one-way repeated measures ANOVA (factor: color change). FS and FM were analyzed by two-way ANOVA (factors: Material*Post-Curing Time). KHN was analyzed individually for each material by two-way ANOVA (factors: Depth*Post-Curing Time). RESULTS: The post-curing time significantly influenced the ΔE00, FS, FM and KHN of all the evaluated materials. COS and SMA presented ΔE00 values above the acceptability threshold after 5 and 10 min of post-curing, respectively. The FS of RES reached a plateau after 5 min of post-curing, and for PRI and SMA, the FS stabilized after 10 min of post-curing. The post-curing process improved the KHN of the tested materials, and longer exposure periods were associated to higher KHN values at all the evaluated depths. SIGNIFICANCE: A fine adjustment of the post-curing time is crucial to produce adequate mechanical properties in 3D-printed restorative resins, while minimizing the color alterations on the restorations. For the evaluated resins, 5-10 min of post-curing will result in adequate mechanical properties, without affecting the acceptability in the color of the material. However, the results are material-dependent, and evaluation of each specific resin is advised.

Effects of extending duration of exposure to curing light and different measurement methods on depth-of-cure analyses of conventional and bulk-fill composites.

This study evaluated the effect of extending the duration of exposure to curing light on the depth of cure of two conventional (RBC1-conventional and RBC2-conventional) and two bulk-fill (RBC1-bulk and RBC2-bulk) resin composites. Polywave and single-peak photocuring units were used. Cylinder-shaped specimens were exposed to curing light either for the time period recommended by the manufacturer or twice the length of that time, and depth of cure was estimated using manual scraping (similar to the ISO-4049 standard) and solvent immersion techniques. Depth of cure was analyzed, using two-way ANOVA, for the factors measurement method and exposure time. For RBC1-conventional and RBC1-bulk, the solvent immersion technique estimated a greater depth of cure than did manual scraping; for RBC1-conventional, both techniques and both light-exposure time periods resulted in a depth of cure of >2 mm; and for RBC1-bulk, only the solvent method after photocuring for twice the manufacturer's recommended time resulted in a depth of cure of 5 mm. For RBC2-conventional and RBC2-bulk, neither technique nor exposure time resulted in estimated depths of cure that matched those indicated by the manufacturer. The results suggest that extending the duration of photopolymerization increases depth of cure. Also, calculation of depth of cure can vary according to the measurement technique used.

Association between creatine kinase activity, oxidative stress and selenoproteins mRNA expression changes after Brazil nut consumption of patients using statins.

BACKGROUND & AIMS: Although the mechanisms by which statins promote muscle disorders remain unclear, supplementation with dietary antioxidants may mitigate statins' side effects. This study aimed to investigate whether the consumption of Brazil nuts modulates serum creatine kinase (CK) activity in patients regularly using statins. METHODS: The study was performed in the Ribeirão Preto Medical School University Hospital. Thirty-two patients in regular use of statins were divided according to CK activity levels (G1: increased or G2: normal) and received one unit of Brazil nut daily for 3 months. Body composition, blood selenium (Se) concentrations, erythrocyte glutathione peroxidase (GPX) activity, oxidative stress parameters, and CK activity were evaluated before and after supplementation. RESULTS: In both groups, supplementation with one Brazil nut daily for 3 months contributed to achieve decreased levels of CK activity in serum, with positive changes in plasma and erythrocyte Se concentrations (p < 0.0001), and increased levels of GPX activity. Among the parameters related to curbing of oxidative stress, we observed reduced levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in both groups after supplementation. We also found a moderately negative association between CK and GPX activity (r = -41; p < 0.02). Expression of selenoproteins GPX1, SELENOP, and SELENON after Brazil nut supplementation was unchanged. CONCLUSION: Brazil nut consumption enhanced the control of CK activity by improving oxidative stress biomarkers in patients using statins but did not modulate mRNA expression of selenoproteins.

Methylselenol release as a cytotoxic tool: a study of the mechanism of the activity achieved by two series of methylselenocarbamate derivatives.

A molecular modeling study has been carried out on two previously reported series of methylselenocarbamate derivatives that show remarkable antiproliferative and cytotoxic in vitro activity, against a panel of human cancer cell lines. These derivatives can be considered as having been constructed by a selenomethyl fragment located over a carbon atom which is decorated with two carbamate moieties, both aliphatic and aromatic, one of them attached by a single bond to the central carbon atom, while the second is connected by a double bond. According to the data obtained, these derivatives can undergo a water-mediated nucleophilic attack on the carbons with marked electrophilic character, which leads to the rupture of C-Se and carbamate C-O bonds. The aliphatic derivatives, series 1, show an early release of methylselenol and a further release of hydroxyl derivatives (alcohols), whereas the aromatic carbamates, series 2, show an early release of phenols followed by the subsequent release of methylselenol. Thus, the activity of the compounds can be related to the progressive release of active fragments. The data that support this connection are related to the overall molecular topology, volume and surface area as well as to quantum parameters such as the relative electrophilic character of the target carbon atoms (measured in terms of positive charge values) or the bond order values, especially concerning the central C-SeCH3 bond and the carbamate ones. Moreover, the data obtained regarding the chromatographic behavior of some representative compounds confirm this proposal.

Vß T cell receptor (TCR) genes in circulating cells of patients with systemic lupus erythematosus and their healthy relatives / Genes del receptor variable beta de células T en células circulantes de pacientes con lupus eritematoso generalizado y sus familiares sanos.

Objective: We investigated the proportion of Vß T cell receptor (TCR) gene expression in peripheral CD3+ lymphocytes in familial and non-familial systemic lupus erythematosus (SLE) patients. Method: The Vß TCR repertoire was studied in 14 families in which several members had SLE. The Vß TCR usage in SLE patients (n = 27) was compared with that in healthy members of these multiplex families (n = 47), in 37 sporadic SLE patients who had no relatives with SLE, and in 15 healthy unrelated controls. Vß TCR repertoire expression was studied by multiparameter flow cytometry with the use of an array of 24 different Vß TCR gene family-specific monoclonal antibodies. Results: We found the same Vß TCR expression profile in the comparisons between sporadic SLE and familial SLE cases and healthy relatives, which included increased expression of Vß 5.2, Vß 11 and Vß 16, and lower expression of Vß 3, Vß 4, Vß 7.1 and Vß 17. Interestingly, solely Vß 17 was differentially expressed among sporadic and familial SLE. Also, increased expression of Vß 9 was the hallmark among familial SLE (casesand h ealthy relatives) in comparison to controls. Conclusion: These results highlight the notion that the final profile of the Vß TCR repertoire seen in familial and non-familial SLE seems to arise from the interaction of genetic, environmental, and immunoregulatory factors. Furthermore, it may contribute to the immunologic abnormalities affecting relatives of SLE patients.

Objetivo: Se investigó la proporción de la expresión génica del receptor variable beta de células T (Vß TCR) en linfocitos periféricos CD3+ en pacientes con lupus eritematoso generalizado (LEG) familiar y no familiar. Método: El repertorio de Vß TCR se estudió en 14 familias que presentaban más de un miembro con LEG. El uso de Vß TCR en pacientes con LEG (n = 27) se comparó con el de los miembros sanos de estas familias (n = 47), con 37 pacientes con LEG esporádico y con 15 controles sanos. La expresión del repertorio de Vß TCR se estudió por citometría de flujo multiparamétrica utilizando un arreglo de 24 diferentes anticuerpos monoclonales específicos de genes familiares para Vß TCR. Resultados: Se encontró el mismo perfil de expresión en las comparaciones entre los casos de LEG esporádico y familiar, así como en los consanguíneos sanos de las familias multicasos, que incluía una expresión incrementada de Vß 5.2, Vß 11 y Vß 16, y una menor expresión de Vß 3, Vß4, Vß 7.1 y Vß 7. De manera interesante, solo Vß 17 se expresó de modo diferente entre casos familiares y esporádicos de LEG. Igualmente, la expresión incrementada de Vß 9 fue el distintivo entre los casos de LEG familiar (casos y consanguíneos sanos) y los controles sanos. Conclusiones: Estos resultados refuerzan la noción de que el perfil final del repertorio Vß TCR observado en LEG familiar y no familiar parece surgir de la interacción de factores genéticos, ambientales e inmunorreguladores, además de que pueden explicar las alteraciones inmunitarias que se observan en los consanguíneos sanos de pacientes con LEG.

Simultaneous use of multiplex ligation-dependent probe amplification assay and flow cytometric DNA ploidy analysis in patients with acute leukemia.

BACKGROUND: The aim of this work was to simultaneously use multiplex ligation-dependent probe amplification (MLPA) assay and flow cytometric DNA ploidy analysis (FPA) to detect aneuploidy in patients with newly diagnosed acute leukemia. METHODS: MLPA assay and propidium iodide FPA were used to test samples from 53 consecutive patients with newly diagnosed acute leukemia referred to our laboratory for immunophenotyping. Results were compared by nonparametric statistics. RESULTS: The combined use of both methods significantly increased the rate of detection of aneuploidy as compared to that obtained by each method alone. The limitations of one method are somehow countervailed by the other and vice versa. CONCLUSIONS: MPLA and FPA yield different yet complementary information concerning aneuploidy in acute leukemia. The simultaneous use of both methods might be recommended in the clinical setting. © 2017 International Clinical Cytometry Society.

Clinical relevance of P-glycoprotein activity on peripheral blood mononuclear cells and polymorphonuclear neutrophils to methotrexate in systemic lupus erythematosus patients.

To elucidate the relationship between P-glycoprotein activity on peripheral blood leukocytes of systemic lupus erythematosus (SLE) patients with lupus arthritis and the clinical response to methotrexate. An observational study was made in patients with SLE according to ACR criteria 1997 who had arthralgia and arthritis and received methotrexate for ≥3 months. Methotrexate responders and non-responders were compared according to the Clinical Disease Activity Index. Mononuclear cells and polymorphonuclear neutrophils were isolated from SLE patients and P-glycoprotein expression was measured using the relative fluorescence index and percentage of positive cells. The chi-square test was used to compare P-glycoprotein activity between responders and non-responders. Thirty-two patients with a mean age of 45.4 ± 10.7 years were included: 34.4% had a response to methotrexate and 65.6% did not. Mean relative fluorescence units of both mononuclear cells and polymorphonuclear neutrophils were significantly lower in patients with a good response (7.0 ± 4.3 vs. 9.6 ± 3.8; p = 0.041 and 4.2 ± 3.5 vs. 7.6 ± 4.0; p = 0.004). The prevalence of low fluorescence levels (<6 relative fluorescence units), signifying higher P-glycoprotein activity of both mononuclear cells and polymorphonuclear neutrophils, was higher in methotrexate responders than in non-responders (27.3 vs. 4.8%; p = 0.10 and 81.8 vs. 23.8%; p = 0.003, respectively). In SLE patients with joint involvement treated with methotrexate, P-glycoprotein activity was higher in responders to methotrexate than in non-responders. Further studies are required to determine the mechanisms behind this finding and whether P-glycoprotein activity mediates alterations in methotrexate efficacy.

Risk assessment and suicide by patients with schizophrenia in secondary mental healthcare: a case-control study.

OBJECTIVES: To investigate the role of risk assessment in predicting suicide in patients with schizophrenia spectrum disorders (SSDs) receiving secondary mental healthcare. We postulated that risk assessment plays a limited role in predicting suicide in these patients. DESIGN: Retrospective case-control study. SETTING: Anonymised electronic mental health record data from the South London and Maudsley National Health Service (NHS) Foundation Trust (SLaM) (London, UK) linked with national mortality data. PARTICIPANTS: In 242 227 SLaM service users up to 31 December 2013, 635 suicides were identified. 96 (15.1%) had a SSD diagnosis. Those who died before 1 January 2007 (n=25) were removed from the analyses. Thus, 71 participants with SSD who died from suicide over the study period (cases) were compared with 355 controls. MAIN OUTCOME MEASURE: Risk of suicide in relation to risk assessment ratings. RESULTS: Cases were younger at first contact with services (mean±SD 34.5±12.6 vs 39.2±15.2) and with a higher preponderance of males (OR=2.07, 95% CI 1.18 to 3.65, p=0.01) than controls. Also, suicide occurred within 10 days after last contact with services in half of cases, with the most common suicide methods being hanging (14) and jumping (13). Cases were more likely to have the following 'risk assessment' items previously recorded: suicidal history (OR=4.42, 95% CI 2.01 to 9.65, p<0.001), use of violent method (OR=3.37, 95% CI 1.47 to 7.74, p=0.01), suicidal ideation (OR=3.57, 95% CI 1.40 to 9.07, p=0.01) and recent hospital discharge (OR=2.71, 95% CI 1.17 to 6.28, p=0.04). Multiple regression models predicted only 21.5% of the suicide outcome variance. CONCLUSIONS: Predicting suicide in schizophrenia is highly challenging due to the high prevalence of risk factors within this diagnostic group irrespective of outcome, including suicide. Nevertheless, older age at first contact with mental health services and lack of suicidal history and suicidal ideation are useful protective markers indicative of those less likely to end their own lives.

Serum Antibodies to Melanocytes in Patients With Vitiligo Are Predictors of Disease Progression.

The aim of this study was to investigate whether the amount of serum antibodies to melanocyte antigens could predict clinical activity or disease progression in patients with vitiligo. A solid-phase enzyme immunoassay was developed to semiquantitate serum antibodies to a human melanocyte extract and was used in 127 patients, 93 of whom showed clinical progression of the disease, while the remaining 34 were quiescent. Results showed different values for clinical sensitivity and specificity depending on the cutoff level for decision, but the overall performance of the test was adequate and supported statistical significance to predict clinical activity/progression or quietness of the disease process. The test might prove useful in deciding the indication and aggressiveness of immunosuppressive therapy in patients with vitiligo. Previous findings suggest that melanocyte-specific antibodies might play a pathogenetic role in the depletion of melanocytes, which characterizes this disorder, and that this depletion might be due to apoptosis following antibody internalization.

In vitro radical scavenging and cytotoxic activities of novel hybrid selenocarbamates.

Novel selenocyanate and diselenide derivatives containing a carbamate moiety were synthesised and evaluated in vitro to determine their cytotoxic and radical scavenging properties. Cytotoxic activity was tested against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds displayed high antiproliferative activity with GI50 values below 10µM in MCF-7, CCRF-CEM and PC-3 cells. Radical scavenging properties of the new selenocompounds were confirmed testing their ability to scavenge DPPH and ABTS radicals. Based on the activity of selenium-based glutathione peroxidases (GPxs), compounds 1a, 2e and 2h were further screened for their capacity to reduce hydrogen peroxide under thiol presence. Results suggest that compound 1a mimics GPxs activity. Cytotoxic parameters, radical scavenging activity and ADME profile point to 1a as promising drug candidate.

Synthesis and antiproliferative activity of novel methylselenocarbamates.

A series of new aliphatic, aromatic and heteroaromatic carbamate derivatives containing a methylseleno moiety were synthesized and evaluated in vitro for their cytotoxic activity against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), K-562 (lymphocytic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds are highly cytotoxic with GI50 values below 10 µM in every tested tumour cell line. Based on its cytotoxic parameters, selectivity index and ADME profile, the biological activity of compound 2, the propyl derivative, was further analysed in CCRF-CEM and HTB-54 cells. Results showed that this compound is able to induce apoptosis in a time- and dose-dependent manner. Involvement of caspases in cell death induction by 2 was detected. Besides, compound 2 was also able to induce cell cycle arrest at G0/G1 in CCRF-CEM cells and at G2/M in HTB-54 cells.

Potential use of the Macrobrachium rosenbergii lectin for diagnosis of T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia is the most common form of cancer in children. Lectins are proteins or glycoproteins from plants or animals that recognize oligossacharides on the cell surface and have been used to characterize the structural changes of oligosaccharides in leukemias. In this study, we used the lectin from the freshwater prawn Macrobrachium (M. rosenbergii), specific for acetyl groups in sialylated glycans, because increased sialylation of glycoproteins and glycolipids has been identified in lymphoblastic leukemias. We compared the specificity of the M. rosenbergii lectin for lymphoblastic leukemias with the specificities of the lectins from Triticum vulgaris, Solanum tuberosum, Arachis hipogaea, and Phytolacca americana. By morphologic and phenotype characterization with a panel of monoclonal antibodies, we identified four types of leukemias from 106 leukemia patients: 11 cases of T-cell acute lymphoblastic leukemia, 61 cases of B-cell acute lymphoblastic leukemia, 24 cases of acute myeloblastic leukemia, and 10 cases of acute biphenotypic leukemia. As determined by cytofluorometric assays, nine of the eleven cases with T-cell acute lymphoblastic leukemia (8 +/- 3 years old) were specifically identified with the lectin from M. rosenbergii. In contrast, only six cases of B-cell leukemia, one case of myeloblastic leukemia, and 2 cases of biphenotypic leukemia were identified with this M. rosenbergii lectin. The other lectins tested showed no capacity to differentiate, in a significant manner, any of the four types of leukemias tested. Thus, the lectin from M. rosenbergii could be considered a useful tool for the diagnosis and study of T-cell acute lymphoblastic leukemia.

Apoptosis of melanocytes in vitiligo results from antibody penetration.

Vitiligo is a rather common disease characterized by depigmentation of skin and mucosae due to the loss of melanocytes, most likely as a result of autoimmune phenomena. In this study we demonstrated apoptotic markers in residual melanocytes in skin biopsies of patients with vitiligo, as well as the presence of serum antibodies to melanocyte-specific antigens in the vast majority of patients. Moreover, we were able to prove that serum IgG antibodies from vitiligo patients, but not from healthy controls, were capable to penetrate into cultured melanocytes in vitro, and trigger them to engage in apoptosis. Our results are consonant with the theory that melanocyte-specific antibodies are responsible for the deletion of melanocytes through antibody penetration and apoptosis.

Minimal residual disease testing in acute leukemia by flow cytometry immunophenotyping: prognostic significance.

Two main techniques are being used for the detection of minimal residual disease (MRD) in acute leukemia (AL): immunophenotypic analysis and polymerase chain reaction (PCR). In this paper, we analyze the results of assessing MRD by means of flow cytometry (FC) in a group of 93 patients with AL who were prospectively studied and treated in a single institution over a 9-year period. The presence or absence of MRD was established at a cut-off level of 2%, as judged by FC; a single result above this level was considered to define the positivity. The patients were grouped in 4 subsets: (1) acute lymphoblastic leukemia (ALL) patients with MRD (n = 36); (2) acute myeloblastic leukemia (AML) patients with MRD (n = 13); (3) ALL patients without MRD (n = 31); and (4) AML patients without MRD (n = 13). The relapse rates in these groups were 17%, 8%, 0%, and 0%, respectively, whereas the overall 7-year survival was 65%, 69%, 83%, and 98%, respectively. Our results support the usefulness of serially assessing MRD in patients with AL by means of FC; because this method is applicable to all cases of AL, despite being less sensitive than a molecular biology study; it is a good option to follow-up patients and to decide therapeutic and timely interventions.

A single-institution, 20-year prospective experience with an affordable Fc-receptor blockade method to treat patients with chronic, refractory autoimmune thrombocytopenic purpura.

In a 20-year period in a single institution, 34 patients with chronic, refractory autoimmune thrombocytopenic purpura were prospectively treated with ex vivo anti-D opsonized autologous red blood cells. All patients had received previous treatment with steroids and/or immunosuppressive agents, and 11 had been splenectomized. Twenty one patients had an increase in the platelet count; in five cases, the increase was more than 50 x 10(9)/L platelets and in 16 the increase was more than 100 x 10(9)/L platelets. Early responses were observed in 20 patients and late responses in seven, whereas seven patients (20%) did not respond at all. Nine of the 20 individuals who achieved an ER had a subsequent drop in the platelet count; however, only three had a drop below 50 x 10(9)/L. When last censored, of the 34 patients, 24 (70%) had a platelet count above 50 x 10(9)/L. The 84-month thrombocytopenia-free (over 50 x 10(9)/L platelets) status of the whole group is 70%, whereas the 84-month complete remission (over 100 x 10(9)/L platelets) status of the whole group is 50%. It is concluded that the use of ex vivo anti-D opsonized red blood cells may represent another, substantially cheaper treatment of patients with chronic, refractory, autoimmune thrombocytopenic purpura.

Instrument- and protocol-dependent variation in the enumeration of CD34+ cells by flow cytometry.

BACKGROUND: The information regarding the minimum number of CD34+ cells that are necessary to reconstitute hematopoiesis in patients undergoing peripheral blood progenitor cell transplantation is quite controversial. Some of the differences in these figures might be due to the selection of antibodies, staining protocols, and acquisition strategies for the flow cytometric enumeration of these cells. STUDY DESIGN AND METHODS: Twenty-seven human umbilical cord blood samples and 33 leukapheresis products were consecutively collected for this study. Cells were stained following two different protocols, both using monoclonal antibodies to CD45 and CD34, and analyzed by the same operator in two different flow cytometers to enumerate the percentage of CD34+ mononuclear cells. RESULTS: Relevant differences in the proportion of cells were encountered, and the correlation between the results yielded by both instruments and protocols, although statistically valid, was suboptimal. CONCLUSIONS: Both interinstrument and interprotocol variation can provide additional explanation for the redundantly reported discrepancies concerning the numbers of CD34 cells that suffice to secure hemopoietic grafting. These results point to the need for new and different standardization approaches in this clinically relevant field.

Parvovirus B19 infection in medical students during a hospital outbreak.

From March to May 2002, a parvovirus B19 (B19) outbreak was identified at a general hospital that serves as a teaching facility for the Universidad Autónoma de San Luis Potosí, Mexico. Medical students attending the hospital presented with symptoms suggestive of B19 infection. Previous studies have suggested that apparent hospital-related B19 outbreaks may be a reflection of B19 infection in the community. A study was undertaken to assess whether exposure to the hospital was a risk factor for B19 infection and to determine to what extent medical students were infected during this outbreak. The incidence of B19 infection in medical students attending the teaching hospital during the outbreak (n=211) was determined and compared to students not attending the hospital (n=96). To assess if a community-wide outbreak had occurred, 80 blood donors were also evaluated for the presence of B19 antibodies. Acute B19 infection was identified in 40 of 119 (33.6%) susceptible students attending the hospital and in 20 of 47 (42.6%) susceptible students not attending the hospital. The frequency of acute infection among susceptible blood donors was lower (9.5%) than in students, but higher than the rate expected during non-epidemic periods. Most infections (68.3%) were asymptomatic. Symptoms reported by infected subjects were not specific for B19 infection. Only 11.7% of subjects with acute infection fulfilled the clinical surveillance definition used to detect cases during the outbreak. In conclusion, hospital exposure was not associated to increased risk of B19 infection among medical students. Medical students may be at increased risk for acquiring and transmitting B19 infection during outbreaks.