Biomedical subjects

M Petrini

Publications and source records attributed to M Petrini.

At least 73 records · Page 4Linked to original sources

PubMed1994

Induction of multidrug resistance (MDR) by transfection of MCF-10A cell line with c-Ha-ras and c-erbB-2 oncogenes.

To investigate the relationship between oncogene activation and appearance of multidrug resistance (MDR) we transfected the human breast epithelial cell line MCF-10A, negative for the expression of the P-glycoprotein, with c-Ha-ras and/or c-erbB-2 oncogenes. The appearance of the MDR phenotype was then studied by evaluating mdr-1 mRNA expression, the presence of P-glycoprotein on the cell membrane and the onset of doxorubicin resistance, together with the effect of the reversing agent verapamil. We found that only MCF-10A transfected with both c-Ha-ras and c-erbB-2 oncogenes acquired the MDR phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Interleukin-6 serum levels in patients with gynecological tumors.

Serum levels of IL-6 were evaluated in a large group of patients with benign or malignant gynecological tumors. The results obtained were correlated with the patients' clinicopathological features and follow-up data. Using a highly sensitive immunoenzymatic method for the evaluation of serum IL-6 levels, we observed that > 95% of normal healthy women exhibited values within the range of 1.9-6 pg/ml. Using a cut-off of 6 pg/ml, elevated levels of serum IL-6 were found in 53% of 45 patients with primary epithelial ovarian cancer and less frequently in patients with endometrial and cervical cancer (37% and 10% respectively). Elevated levels of IL-6 were occasionally seen in patients with benign disease. IL-6 serum levels appeared to be less sensitive than CA 125 in ovarian cancer diagnosis. In cancer patients, increased IL-6 serum levels were related to the presence of the tumor since all post-operative patients exhibited a marked decrease. In patients with advanced ovarian cancer post-operative levels of IL-6 correlated with residual disease. Very high levels of IL-6 were observed in the ascitic fluid of 9 ovarian cancer patients, but IL-6 mRNA was not detected in tumor cells. This suggests that the increased production of IL-6 observed in ovarian cancer is reactive. Higher levels of IL-6 were found in patients unresponsive to chemotherapy, as compared with responsive ones. Univariate analysis of survival data suggests that increased IL-6 serum levels correlate with negative prognosis.

Adult↗

PubMed1994

Effects of glycosaminoglycans on U-937 leukemia cell proliferation and differentiation: structure-function relationship.

Glycosaminoglycans (heparins, dermatan sulfate, chondroitin sulfate) with different structures and physicochemical properties were evaluated for their capacity to influence proliferation and differentiation of U-937 cell line. The contrasting and specific effects of glycosaminoglycans (depending on their structures and properties) on a leukemia cell line could help explain the regulation of proliferative and/or differentiative processes of hematopoietic cells in order to clarify the control of development and differentiation of hematopoietic progenitor cells by bone marrow extracellular matrix. Heparin from beef intestinal mucosa, heparan sulfate from beef spleen, dermatan sulfate from beef intestinal mucosa, and chondroitin sulfate from bovine trachea were extracted and purified, and their purity, structures, and physicochemical properties were evaluated. Fast-moving heparin was obtained by its selective precipitation as barium salt, and partially desulfated and re-N-sulfated heparin was produced by chemical modifications. Different glycosaminoglycans were tested to evaluate their effects on proliferation and differentiation processes of a monoblastic leukemia cell line (U-937). Heparin and derivatives (from 0.1 to 100 micrograms/ml) inhibit cell proliferation; heparan sulfate does not produce modifications, while chondroitin sulfate and dermatan sulfate (from 0.01 to 100 micrograms/ml) significantly stimulate cell growth. Cell differentiation was evaluated by cytoenzymatic determination of alpha-naphthyl butyrate esterase and by fluorescein-labeled anti-HLA-DR, anti-CD11b, and anti-CD14 antibodies. Nitro blue tetrazolium reduction and phagocytosis were also evaluated. Heparin and derivatives significantly increase U-937 differentiation. Heparin sulfate has no effect, while chondroitin sulfate and, to a lesser extent, dermatan sulfate, induce a strong decrease of differentiative markers. The regulation of U-937 cell properties appears to be related to charge density and to the amount of N-sulfate and N-acetyl groups. In particular, glycosaminoglycans with lower sulfate-to-carboxyl ratios and N-sulfate group percentages (chondroitin sulfate and dermatan sulfate) stimulate proliferation and produce a decrease of differentiative markers; on the contrary, polysaccharides with high charge density and N-sulfate group amounts (heparin and derivatives) inhibit U-937 proliferation and induce terminal differentiation. A previous paper (N. Volpi, L. Bolognani, A. Conte, and M. Petrini, (1993) Leukemia Res. 17, 789-798) demonstrates dissimilar effects on U-937 cells by chondroitin sulfates with different structures and physicochemical properties. In this study we confirm the importance of glycosaminoglycan structures and physicochemical properties in regulating cell functions. Possible mechanisms of action are discussed.

Animals↗

PubMed1994

Basal and thrombin-stimulated platelet cell calcium.

To study platelet cell calcium in dogs, we measured the fura-2-determined calcium concentration (Cai) in platelets derived from blood drawn through indwelling arterial catheters in four dogs. Platelet samples were obtained 3 days a week for 39 days. Canine platelet Cai averages 40.5 +/- 1.7 nmol/L when corrected for extracellular fura-2 dye (n = 46); this mean is significantly smaller than the value obtained without such a correction (50.2 +/- 2.0 nmol/L, P < .05). The amplitude of thrombin-induced Ca2+ transients is proportional to basal Cai, increasing 4.9 +/- 0.9 nmol/L peak Ca2+ per nmol/L increase in baseline Ca2+.

Animals↗

PubMed1994

Differential modulation of P-glycoprotein expression by dexamethasone and 3-methylcholanthrene in rat hepatocyte primary cultures.

Spontaneous and culture condition-dependent changes in P-glycoprotein expression and activity have been monitored in primary cultures of rat hepatocytes by using immunoblotting, PCR and fluorimetric techniques. In hepatocytes cultured in basal medium without addition of dexamethasone or 3-methylcholanthrene, mdr mRNA and P-glycoprotein increased progressively throughout a 72 h culture period, in concert with an enhancement in the ability to extrude the fluorescent dye Rhodamine-123. Addition of 1 microM dexamethasone to the culture medium slowed down the increase in mdr mRNA and P-glycoprotein, while inducing a significant increase in the efficiency of R-123 efflux. Addition of either 100 nM or 10 microM DEX produced different changes in mdr mRNA and protein, unrelated to the rate of Rhodamine-123 extrusion. When 50 microM 3-methylcholanthrene was added to the culture medium in the absence of any hormone supplementation, no significant changes in P-glycoprotein activity and expression took place, in comparison with control cultures. On the contrary, in the presence of dexamethasone (100 nM and 1 microM), 3-methylcholanthrene induced an increase in mdr mRNA and in the amount of immunoblottable protein during culture, without producing any concomitant increase in the efficiency to extrude Rhodamine-123. The last phenomenon resulted to be an artefact, since 3-methylcholanthrene was shown to inhibit Rhodamine-123 transport competitively. These results indicate that rat hepatocyte P-glycoprotein may be variously modulated in vitro, by supplementing culture medium with hormones and/or xenobiotics. Functional activity of the P-glycoprotein is not necessarily related with protein amount and/or mdr RNA.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Vitamin D binding protein is produced by human monocytes.

The expression of the DBP (vitamin D binding protein) gene was investigated in monocytes and in peripheral blood lymphocytes. DBP message was amplified through 35 cycles of PCR amplification using specific oligonucleotide primers. PCR products of the expected size were further identified by Southern blotting using a specific DBP probe. No expression of the DBP gene could be detected in peripheral blood lymphocytes, nor in the monocyte-derived U 937 cell line. In contrast, message for DBP was identified in monocytes activated with lipopolysaccharide when analyzed between 6 and 10 h following stimulation. These results suggest that the temporal expression of the DBP gene could play a major role in the activation of monocytes by 1-25(OH)2D3.

Base Sequence↗

PubMed1993

Idarubicin is active on MDR cells: evaluation of DNA synthesis inhibition on P388 cell lines.

Multidrug resistance is frequently found in patients affected by hematological malignancies and has been related to a poor prognosis of acute leukemia. In the present paper we report results concerning the activity of idarubicin, an anthracycline derivative, on the leukemic P388 and P388 doxorubicin-resistant cell lines. The results clearly show that idarubicin inhibits DNA synthesis in the resistant cell line more actively than doxorubicin.

Animals↗

PubMed1993

Is binding of vitamin D binding protein related to cell differentiation?

Vitamin D binding protein (Gc) is present on the surface of several blood cells and may interfere with the activity of 1,25(OH)2D3. It has previously been reported that Gc may bind to the U-937 line which is known to differentiate upon exposition to 1,25(OH)2D3. In the present paper, we evaluate the expression of Gc on the surface of U-937 and HL-60 lines. Both cell lines did not express Gc on their surface but U-937 cells were able to bind human purified Gc added to the medium whereas HL-60 were not. After culturing with 1,25(OH)2D3, HL-60 became able to bind Gc. This property seems to be related to the monocytic differentiation induced by 1,25(OH)2D3. Conversely, when present together, 1,25(OH)2D3 reduces binding on U-937.

Calcitriol↗

PubMed1993

Effects of chondroitin sulfates with different structures on leukemia cells: U-937 cell proliferation and differentiation.

Chondroitin sulfates extracted and purified by different manufacturers were tested to evaluate their effects on proliferation and differentiation processes of U-937 cells. The different chondroitin sulfates were evaluated for purity, structure and physicochemical properties. The three chondroitin sulfates utilized did not present other contaminant glycosaminoglycans and proteins and had about the same relative molecular mass but different disaccharide patterns and charge density. Chondroitin sulfates with small amounts of disulfated disaccharides and low charge density, at 5 micrograms/ml concentration, doubled (about + 133%) cell proliferation in comparison to controls. In contrast, chondroitin sulfates with large amounts of disulfated disaccharides and high sulfate to carboxyl ratio were less effective (about + 15%) in stimulating cell proliferation at low concentration. A decrease of U-937 cell proliferation was observed in proportion to the increased amounts of chondroitin sulfate with low sulfate to carboxyl ratio. On the contrary, chondroitin sulfate with large amounts of disulfated disaccharides produced increased cell proliferation depending on concentration. Small amounts (5-10 micrograms/ml) of chondroitin sulfates with low charge density reduced the differentiative process of U-937 cells. Chondroitin sulfate with large amounts of disulfated disaccharides and high charge density seemed to be able to produce a significant decrease of differentiative processes only at very high concentrations (1000 micrograms/ml). These contrasting effects of chondroitin sulfates with different disaccharide patterns (and structure) and charge density on a leukemia cell line could help to explain the regulation of proliferative and/or differentiative processes of hemopoietic cells. This is underlined by the changes of types, physicochemical properties and structure of glycosaminoglycans induced by different extracellular factors and agents.

Antigens, CD↗

PubMed1993

Reversing of chlorambucil resistance by ethacrynic acid in a B-CLL patient.

We evaluated the reversing activity of ethacrynic acid in a B-CLL patient resistant to chlorambucil. The glutathione S-transferase (GST) activity, measured in peripheral blood lymphocytes, resulted extremely elevated. Ethacrynic acid, at pharmacological concentrations, partially reversed chlorambucil resistance and this result appeared related to the increased GST levels.

Aged↗

PubMed1993

Vitamin D3 administration and multidrug resistance in acute nonlymphoblastic leukemia.

This article reports preliminary results from a pilot study started in 1986 on patients with acute myeloblastic leukemia treated for several months with low-dose arabinosylcytosine and 1(OH)D3. During treatment or at the time of relapse, a monoblastic component was frequently found. A high percentage of patients were P-170-positive. In 2 patients it was possible to show that blasts, previously P-170-negative, became positive after treatment. In these 2 patients, failure of clinical response to antileukemic therapy was associated with this phenotype. The addition of the revertant drug nicardipine to the previously inactive treatment induced a partial response. Thus, previously reported in vitro observations on the differentiating activity of vitamin D3 metabolites, possible induction of multidrug chemoresistance by differentiating agents and the revertant activity of the Ca++ antagonist nicardipine appear to be confirmed in vivo in the reported patients.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Third generation chemotherapy with P-VABEC for aggressive non-Hodgkin's lymphomas of the elderly.

Between July 1990 and March 1992, 23 elderly patients with intermediate or high-grade non-Hodgkin's lymphomas (NHL) received a combination chemotherapy (P-VABEC: Etoposide, Adriamycin and Cyclophosphamide on days 1, 15, 29, 43, Vincristine and Bleomycin on days 8, 22, 36, 50 and Prednisolone on weeks 1-9). The regimen was administered on an outpatient basis. The median age of the patients was 67 years (range 60-78); 15 were previously untreated, 8 were on second line therapy; 6 patients (44%) had stage IV disease, 19 (83%) B symptoms, 15 (65%) had bulky disease, and (26%) bone marrow involvement. The complete remission (CR) rate was 57%, and the partial remission (PR) rate 43%, with an overall response rate of (100%). No difference in response rate was observed between previously untreated patients and patients treated with P-VABEC as second-line therapy while hematological and clinical toxicity were very mild.

Aged↗

PubMed1993

Activity of different revertant agents on multidrug resistance: in vitro evaluation of their combination.

The revertant activity of different compounds has been assayed on a multidrug-resistant human breast-cancer cell line (MCF 7/Dx). The calcium-channel blocker nicardipine showed the higher revertant ability when compared to cefoperazone or cyclosporin A at concentrations close to the pharmacological range. Interestingly, nicardipine was able to increase the revertant activities of both cefoperazone and cyclosporin A, but these latter were not able to enhance each other over a plateau. However, a limit of about 70% of growth inhibition of the line cultured in the presence of 60 microM doxorubicin seems to be insuperable at the concentrations employed. The combination of the three drugs brings the concentrations of drugs to the point at which the maximum possible inhibition is reached in the pharmacological range, but the complete reversion of chemoresistance is not reached when the doxorubicin is added at the concentration capable of reducing the cell proliferation by 50%.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Scanning electron microscopy of multidrug resistant cells in haematological and mammary malignancies.

Multidrug resistance (MDR) is frequently found in haematologic malignancies. It has been shown that MDR is often related to the expression of a membrane glycoprotein (P-170) which actively pumps many hydrophobic agents out of the cells. Previous electron microscopic investigations revealed morphological differences between P-388 resistant and P-388 sensible cell membranes, but the modulation of the membrane morphology seems to be related to the tumor-cell environment. In order to establish if morphological differences exist between sensitive and resistant cells, both sensitive and resistant strains from three different cell lines were studied by scanning electron microscopy: human leukaemia CEM and vinblastine resistant cells (CEM/VBL100), human breast cancer MCF-7 and mice leukaemia P-388 with the doxorubicin resistant strains (MCF-7/DX and P-388/DX, respectively). The surface of the membranes of the sensitive cells was regular, unlike the resistant ones which proved to be irregular, endowed with long villus-like processes or numerous folds and ruffles. The addition of albumin to the culture medium induced a shift from the resistant to the sensitive phenotype, thus suggesting that the P-388/DX morphology may be linked to the concentration of protein in the culture medium. Exposure to DX, verapamil (VRP) or monoclonal antibody against P-170 (mAb-57) did not modify the surface of the resistant strains, demonstrating that surface irregularities are probably not linked to P-glycoprotein function. Blasts from four P-170 positive leukaemic patients were also analyzed: an irregular shape was always found.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1992

Expression of selected human HOX-2 genes in B/T acute lymphoid leukemia and interleukin-2/interleukin-1 beta-stimulated natural killer lymphocytes.

Although the key role of human homeobox (HOX) genes in development is well established, their function in adult cells is still under scrutiny. We have analyzed, in normal adult blood cell subpopulations, acute lymphoid leukemia (ALL) cells lines, and primary blasts, the RNA expression of all HOX-2 cluster genes (5'-2.5, 2.4, 2.3, 2.2, 2.1, 2.6, 2.7, 2.8, 2.9, 3') and nine genes in the HOX-1, -3, and -4 cluster by Northern blotting, RNAse protection, and/or reverse transcriptase polymerase chain reaction (RT-PCR). The analyzed HOX-1, -3, and -4 genes were never expressed in all tested cell populations. Natural killer (NK) cells activated in interleukin-2 (IL-2)/IL-1 beta-treated cultures exhibit a gradually increasing, abundant expression of three HOX-2 genes (2.2, 2.6, 2.8), while three other genes (2.3, 2.1, 2.7) are expressed at a lower level at late culture times. However, no HOX-2 gene is expressed in quiescent lymphocytes (NK, B and T [T-cell receptor (TCR) alpha/beta, gamma/delta lymphocytes, thymocytes] cells), granulocytes, and monocytes. In B- and T-ALL cell lines, HOX-2 genes are expressed according to different patterns: (1) widespread transcription (seven of nine genes, including 2.3 and 2.6) in the Peer line bearing the TCR gamma/delta; (2) expression of 2.5, 2.2, and 2.6 in the SEZ 627 line, which derives from an HTLV-1+ T-helper leukemia; (3) transcription of 2.3 and 2.6 in both the T-ALL CEM line and four B-ALL lines (interestingly, CALLA- B-ALL lines are constantly 2.3/2.6 RNA+); (4) no HOX-2 gene expression was detected in one T- and two B-ALL lines. Primary blasts from five T- and five pre-B-ALL showed selective expression of one or more HOX-2 genes, namely 2.5, 2.2, 2.6, and 2.7. Our data are compatible with the hypothesis that selected HOX-2 genes play a role in the IL-2/IL-1 beta-induced activation and/or proliferation of normal NK lymphocytes and possibly in the oncogenetic process of some T- and B-ALL.

Base Sequence↗

PubMed1992

Variability among geriatricians in the evaluation of functional disabilities and rehabilitation needs of the elderly.

A formal variability study has been carried out in a geriatric hospital in Genoa, Italy, in order to estimate the degree of agreement between geriatricians in disability and functional assessment, recommendation for rehabilitation treatments, need for mobility and daily activities aids, and decisions about optimal place of treatment (own home, sheltered housing, old peoples' home, nursing home). Sixteen long-stay geriatric patients, average age 83 years, were visited by eight geriatricians, a patient receiving from two to five visits. The participating physicians could visit the patients at their leisure, had access to clinical records and could interview a nurse well acquainted with the patient. A marked variability was observed for most items, e.g. the agreement concerning the recommendation for individual physiotherapy was only 52%. The results of this study may not be generalized to other situations and to actual practice; however, variability studies of this kind, that assess diagnosis habits, treatment and managerial decisions at the same time, may be useful to pinpoint the most important problems and to stimulate professionals' participation in proper Quality Assurance projects.

Aged↗

PubMed1992

Retroperitoneal seminoma secondary to 'burned out' testicular tumor in an acromegalic patient.

We report a case of an acromegalic patient with a retroperitoneal seminoma secondary to a testicular tumor which had completely disappeared. Testicular ultrasonography did not show any pathological mass and histological examination indicated that the normal testis had been totally replaced by fibrous tissue, without neoplastic cells. Our patient had high levels of growth hormone (GH) and prolactin (PRL), both hormones with high immunostimulating effect, and an increase of interleukin-2 receptor-positive lymphocytes, a finding supporting enhanced immunological activity. Thus, we cannot exclude that the immunological pattern of this acromegalic patient may have played some role in the tumoral destruction.

Acromegaly↗

PubMed1991

Distribution of the 1,25 dihydroxy-vitamin D3 receptor in the bursa of Fabricius of chicken.

The vitamin D3 metabolite 1,25(OH)2D3 is probably involved in B lymphocyte ontogeny. We therefore determined the distribution of the 1,25(OH)2D3 receptor in the bursa of Fabricius and spleen cells of 7-day-old chicks, by immunohistochemistry using a monoclonal antibody against the chick intestinal cell 1,25(OH)2D3 receptor. The bursa cells of young (7-day-old) chicks contained large amounts of receptor while the spleen cells did not. The bursa cells of older (35-day-old) chicks contained fewer receptors, but the number of receptors in the spleen increased.

Aging↗