Biomedical subjects
Publications and source records attributed to Renata Zadro.
Standard controls and best practice guidelines advance acceptance of data from research, preclinical and clinical laboratories by providing a means for evaluating data quality. The External RNA Controls Consortium (ERCC) is developing commonly agreed-upon and tested controls for use in expression assays, a true industry-wide standard control.
The Scientific Committee of Molecular Biology Techniques (C-MBT) in Clinical Chemistry of the IFCC has initiated a joint project in co-operation with the European Commission, Joint Research Centre, Institute of Reference Materials and Measurements to develop and produce plasmid-type reference materials (RMs) for the analysis of the human prothrombin gene G20210A mutation. Although DNA tests have a high impact on clinical decision-making and the number of tests performed in diagnostic laboratories is high, issues of quality and quality assurance exist, and currently only a few RMs for clinical genetic testing are available. A gene fragment chosen was produced that spans all primer annealing sites published to date. Both the wild-type and mutant alleles of this gene fragment were cloned into a pUC18 plasmid and two plasmid RMs were produced. In addition, a mixture of both plasmids was produced to mimic the heterozygous genotype. The present study describes the performance of these reference materials in a commutability study, in which they were tested by nine different methods in 13 expert laboratories. This series of plasmid RMs are, to the best of our knowledge, the first plasmid-type clinical genetic RMs introduced worldwide.
Acute promyelocytic leukemia (APL) M3 is an acute myeloid leukemia (AML) subtype characterized by proliferation of malignant promyelocytes with mature myeloid immunophenotype and the translocation t(15;17)(q22;q11), which results in the fusion of retinoic acid receptor-alpha (RARalpha) gene on chromosome 17 and the gene PML on chromosome 15. There are three M3 morphologic variants: the typical hypergranular form and the microgranular and basophilic variants. Although most leukemic cells in M3 patients express t(15;17), other cytogenetic abnormalities have also been reported. Also, there are three molecular variants of the PML/RARalpha transcript (bcr1, bcr2, bcr3). Blasts had typical hypergranular appearance (13 patients) with a mature myeloid immunophenotype (HLA-DR(-),CD13(+), and/or CD33(+)) (10 patients) in the majority of patients with M3 followed in this study. The typical translocation [t(15;17)(q22;q11)] was detected by cytogenetic analysis in 5 M3 patients, but PML/RARalpha was positive in 13 out of 15 patients, as assessed by RT-PCR (8 patients with bcr1 and 5 with bcr3 subtype). Cytogenetic diversity was found in three patients (1 with t(17;17), 1 with +8, and 1 with add (7)(q22); -7; +8). According to many studies, leukemic cell heterogeneity in APL influences the clinical outcome of disease. The analysis of certain leukemic cell characteristics on the clinical outcome in our study revealed that patients with bcr3 had shorter medians of first remission and survival in comparison to patients with the bcr1 isoform of PML/RARalpha. Also, the clinical relapse of disease in 4 APL patients with reverted PML/RAR alpha positivity is consistent with the view that detection of PML/RARalpha by RT-RCR in patients in remission implies a poor prognosis. On the contrary, lack of detection of PML/RARalpha by RT-PCR at least three times is a sign of long remission and survival.
A better understanding of cellular and molecular mechanisms involved in response to mechanical stress is a prerequisite for future improvements in orthodontic treatment. To expand the application of molecular biology techniques in this area of research, we developed and characterized a mouse tooth movement model. The aim of this study was to biomechanically characterize this model and to evaluate the effect of orthodontic stress on the proliferation of periodontal osteoblasts. We used an orthodontic coil spring appliance with a low force/deflection rate, which produced an average force of 10-12 g. This design provided a predictable tipping movement of the molar with the center of rotation at the level of root apices. Histological observations of paradental tissues revealed a response favoring a fast onset of tooth movement and deposition of new osteoid starting after 3 days of treatment. The effect of treatment on the histomorpometric parameter of the number of osteoclasts per unit bone perimeter was determined after 1, 2, 3, 4, 6, and 12 days of treatment. Starting with day 2, the osteoblast number showed a modest but consistent increase in treated periodontal sites at all time-points, ranging from 14 to 39% and becoming significant only at day 6. Only a moderate increase in the number of osteoblasts in the areas of otherwise intense bone matrix synthesis suggests that, during bone formation, proliferation of cells has a smaller role compared to a marked increase in differentiation of individual cells. The mouse model, which allows for a controlled, reproducible, orthodontic mechanical loading, can be applied to both wild-type and transgenic animals and should enhance the research of the transduction of mechanical orthodontic signal into a biological response.
A better understanding of cellular and molecular mechanisms involved in response to mechanical stress is a prerequisite for future improvements in orthodontic treatment. To expand the application of molecular biology techniques in this area of research, we developed and characterized a mouse tooth movement model. The aim of this study was to biomechanically characterize this model and to evaluate the effect of orthodontic stress on the proliferation of periodontal osteoblasts. We used an orthodontic coil spring appliance with a low force/deflection rate, which produced an average force of 10-12 g. This design provided a predictable tipping movement of the molar with the center of rotation at the level of root apices. Histological observations of paradental tissues revealed a response favoring a fast onset of tooth movement and deposition of new osteoid starting after 3 days of treatment. The effect of treatment on the histomorpometric parameter of the number of osteoclasts per unit bone perimeter was determined after 1, 2, 3, 4, 6, and 12 days of treatment. Starting with day 2, the osteoblast number showed a modest but consistent increase in treated periodontal sites at all time-points, ranging from 14 to 39% and becoming significant only at day 6. Only a moderate increase in the number of osteoblasts in the areas of otherwise intense bone matrix synthesis suggests that, during bone formation, proliferation of cells has a smaller role compared to a marked increase in differentiation of individual cells. The mouse model, which allows for a controlled, reproducible, orthodontic mechanical loading, can be applied to both wild-type and transgenic animals and should enhance the research of the transduction of mechanical orthodontic signal into a biological response.
Philadelphia chromosome positive chronic myeloid leukemia (Ph+ CML), in advanced stage of disease, is resistant to standard chemotherapy. Imatinib was found to be effective in these patients. This paper shows our preliminary results. Imatinib mesylate was given to 15 patients during a 9-month period. Nine of them were in accelerated phase and 6 in blastic crisis of Ph+ CML. Patients were evaluated for hematologic and cytogenetic responses. Imatinib mesylate induced complete haematologic response in 12 patients (80% and cytogenetic response in 8 patients (53%). Six patients (40%) had a major cytogenetic response. After a 9-month follow up Ph+ CML progressed in 9 patients (60%) and 4 of them died. The most frequent adverse effects were edema, nausea, neutropenia and thrombocytopenia. Imatinib mesylate has a substantial, but short term activity in the accelerated phase and blastic crisis of the Ph+ CML.