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Biomedical subjects

V Santini

Publications and source records attributed to V Santini.

At least 55 records · Page 3Linked to original sources

Clonogenic growth of acute non-lymphocytic leukemia cells in serum-free medium.

We devised a serum-free medium for growth of leukemic colony-forming units (CFU-L), enriched with albumin, transferrin, lipids, insulin, hydrocortisone and oligoelements. Blast cells from 15 patients affected by acute non-lymphocytic leukemia were grown in this medium in the presence of human placental conditioned medium obtained under serum-free conditions (sfHPCM). Their clonogenic growth was comparable with that obtained in a serum-containing system. Furthermore, when serum-free cultures were carried out in absence of sfHPCM, either CFU-L growth was prevented or, if clones were obtained, the cultures showed a marked decrease in clonogenicity, indicating their strict dependence on growth factors.

Adult↗

Proliferation and cell loss of human leukemic cell subpopulations in liquid culture.

A kinetic study was performed on leukemic blasts from patients with acute myeloid leukemia, separated into 2 subpopulations by a specific density gradient. The growth curve and the [3H]-thymidine uptake were simultaneously analyzed. While cumulative nucleotide uptake fitted with the growth kinetics in the low-density fraction, such a concordance was not found in the high-density subpopulation. That indicated the occurrence of simultaneous growth and loss in the high density fraction, which could not be evaluated by a simple numerical determination.

Cell Division↗

Glycosaminoglycan polysulfate in old-age dementias: a factor-analytic study of change in psychopathologic symptoms.

In a multicenter clinical trial, two dosages of glycosaminoglycan polysulfate were compared in patients with primary degenerative dementia and multi-infarct dementia. Psychopathologic symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). A factor analysis of this scale revealed four factors in this population. During the clinical trial, significant improvements were noted on the primary BPRS factor (i.e. depressive withdrawal), as well as on total BPRS score. There was a tendency for greater improvement in the primary degenerative dementia group than in the multi-infarct dementia group.

Aged↗

Study of the action of some centrally acting drugs on the EEG and on a conditioned avoidance reflex in the rabbit.

A study was carried out on the effect of perphenazine, diazepam, benactyzine, morphine and a new central analgesic, viminol, onboth EEG and behaviour in rabbits with chronically implanted electrodes trained to a conditioned escape reflex. The results obtained are discussed considering the mechanism and site of action of the different drugs: the experimental procedure adopted is recommended to obtain additional informations on the properties of centrally acting drugs.

Animals↗

In vitro chemosensitivity testing of leukemic cells: development of a semiautomated colorimetric assay.

A rapid chemosensitivity assay was developed, employing the human continuous leukemic cell lines HL 60, K 562, FLG 29.1. This automated colorimetric assay is based on the characteristic of viable, metabolically active cells to cleave p-iodonitrotetrazolium violet (INT) into a red formazan derivative, whose optical density is readable at 492 nm by an automated microtiter-plate reader photometer. A linear relationship was found between the viable cell number and the optical density of INT cleaved by the cellular samples. Dead cells did not reduce INT and did not interfere with the formazan derivative generation and the photometric reading. Leukemic cell lines were also tested for INT formazan derivative generation after exposure to antileukemic drugs at various concentrations, representative of plasma levels obtainable in vivo. A dose-dependent inhibition was detected, with different sensitivity patterns, related both to the drugs and to the different cell lines. A significant correlation between the viable cell number and the amount of tetrazolium salt cleaved was also demonstrated after drug exposure. INT assay allows the processing of a great number of samples and gives the opportunity to screen several drugs, saving time and yielding fully reliable results.

Autoanalysis↗

In vitro chemosensitivity testing of leukemic cells: prediction of response to chemotherapy in patients with acute non-lymphocytic leukemia.

The in vitro chemosensitivity to daunorubicin and cytosine arabinoside of blast cells derived from 35 patients affected by acute non-lymphocytic leukemia was assessed by a semiautomated tetrazolium-based colorimetric assay, by the use of p-iodonitrotetrazolium violet. The results of the in vitro testing were then compared a posteriori to clinical outcome of patients, who followed a schedule of therapy which always included the drugs tested in vitro. Three dosages of drugs were employed to allow the determination of a dose-response curve, which was obtained for all the patients. The data collected in INT assay correlated with the clinical sensitivity of patients, evaluated in terms of achievement of complete remission. For the dosage of ARA-C 500 ng/ml it was possible to establish a significant cutoff between responders and non-responders to therapy, while an acceptable distribution of sensitivity/resistance prediction was found for DNR 500 ng/ml and 5 micrograms/ml. Present results, together with rapid and easy execution of the test, encourage the use of INT assay in screening leukemic patients' sensitivity to antiblastic drugs before treatment or, in case of resistance to classical chemotherapy, in detecting individual sensitivity to alternative drugs.

Adolescent↗

Assessment of PTT 119 activity on acute nonlymphoblastic leukemia cells by [3H]-thymidine uptake inhibition and cluster analysis.

PTT 119, a new antineoplastic agent, was demonstrated to have antileukemic activity on murine and human cell lines. In this study we assessed the effect of this drug, at concentrations ranging from 100 ng/ml to 10 micrograms/ml, on fresh human leukemic cells from 12 patients affected by ANLL, evaluating the impairment of DNA synthesis in terms of [3H]-thymidine uptake inhibition. Most leukemic cell populations appeared to be responsive to the drug in a dose-related fashion. By cluster analysis, it was possible to discriminate subsets of samples according to PTT 119 sensitivity, and to investigate cross resistance with cytosine arabinoside and daunorubicin. This preclinical study indicates that PTT 119 may deserve applications in the treatment of acute nonlymphoblastic leukemia patients.

Anemia, Refractory, with Excess of Blasts↗

Quantitation of bcl-2 oncogene in cultured lymphoma/leukemia cell lines and in primary leukemia B-cells by a highly sensitive RT-PCR method.

BACKGROUND: The bcl-2 gene, isolated from the t(14;18) chromosomal translocation breakpoint, is able to prevent apoptotic death induced by various stimuli in different tissues. Therefore bcl-2 oncogene expression could be a key parameter for investigating the molecular mechanisms involved in the apoptosis of normal and neoplastic hematopoietic cells. METHODS: In order to evaluate bcl-2 expression in both follicular B-lymphomas carrying or not carrying the 14;18 translocation and in lymphatic leukemias, we optimized an internal standard-based method of reverse transcriptase-polymerase chain reaction (RT-PCR) for the rapid quantitation of bcl-2 mRNA cellular levels. A simple purification of the reverse transcription products resulted in very high PCR efficiency, so that radioactive labelling of the amplification products was avoided. RESULTS: bcl-2 mRNA levels proved to be higher in t(14;18) than in t(14;18) negative cell lines, and higher in primary leukemia pre-B cells than in early-B cells. Tested for sensitivity by identifying minimal residual t(14;18) B cells expressing the bcl-2/IgH gene, this RT-PCR method was able to detect bcl-2/IgH mRNA from just one t(14;18) positive cell out of ten million t(14;18) negative cells. CONCLUSIONS: The RT-PCR method we optimized appears to be suitable for clinical use in both leukemia/lymphoma characterization and in lymphomatous disease follow-up.

Base Sequence↗

Detection of bcr/abl transcripts by RT-PCR and their colorimetric evaluation in chronic myeloid leukemia patients receiving allogeneic bone marrow transplantation.

BACKGROUND: Chronic myeloid leukemia (CML) is a disease characterized by the presence of a unique molecular marker, i.e. the fusion gene bcr-abl and its mRNA and protein products. This marker permits minimal residual disease follow-up after bone marrow transplantation (BMT) through cytogenetic or molecular analysis. Although the reverse transcriptase polymerase chain reaction (RT-PCR) method is largely employed, the clinical value and impact of a positive RT-PCR as a herald of hematological relapse has not yet been definitively ascertained. METHODS: In order to verify the frequency of bcr-abl positivity in CML patients who underwent alloBMT, we performed serial two-step RT-PCR on 63 peripheral blood and bone marrow specimens obtained at different times after non T-cell-depleted BMT from 16 CML patients treated in our Institution. After amplification, RT-PCR products were always checked by liquid hybridization with a specific probe. Median molecular follow-up after BMT was 38 months (range 2-144 months). RESULTS: None of the patients studied presented clinical hematological relapse after BMT. Six out of sixteen patients were found to be positive for bcr-abl. PCR positivity appeared in 4/6 patients more than one year post-BMT and in 2/6 patients within one year post BMT. In both instances PCR was an isolated finding in 5/6 patients and reverted to negativity in subsequent analysis; only one case was PCR-positive twice. It is noteworthy that RT-PCR positivity appeared in five patients presenting acute or chronic graft versus host disease (GVHD) and in one patient who had received MUD-BMT. CONCLUSIONS: In our cohort of patients, transient bcr-abl positivity had no clinical relevance and was also found in MUD-BMT without heralding hematological relapse. Our observations further stress the importance of applying only quantitative PCR methods during the post BMT follow-up of CML patients.

Adolescent↗