[Rationale and current results of loco-regional chemotherapy in hepatic metastases of colorectal carcinoma].
Explore the source record for details and available documents.
Antineoplastic Agents↗
Biomedical subjects
L Frati
Publications and source records attributed to L Frati.
Estrogen and antiestrogen modulation of the levels of mouse natural killer activity and large granular lymphocytes.
We investigated the time course of the 17 beta-estradiol effect on mouse natural killer (NK) activity and the number of splenic large granular lymphocytes (LGL), a cell population recently associated with natural cytotoxicity and enriched in low density fractions of Percoll discontinuous density gradients. After 7 days of in vivo treatment with estrogen, an increased cytotoxicity against YAC-1 lymphoma cells was observed using only as effectors cells recovered from higher density fractions, usually devoid of NK activity. In contrast, after a 30-day treatment, augmented NK activity and an increase in LGL number were observed in the lower density Percoll fractions. Similar results were observed after a 30-day treatment with the antiestrogen tamoxifen. The cytotoxicity of both low density and high density splenocyte fractions was totally abrogated by treatment with antiserum to asialo GM1 plus complement, whereas anti-Thy 1.2 antibody treatment only partially decreased the reactivity. Further estrogen administration up to 60 days decreased both NK activity and LGL number. It is concluded that estradiol can induce opposite effects on NK activity depending on the time of treatment, with stimulation of NK activity during the first 30 days after treatment followed by depressed NK activity 1 month later.
Animals↗
Human T-lymphotropic retrovirus infection in Italy.
Explore the source record for details and available documents.
Acquired Immunodeficiency Syndrome↗
Effect of 4-hydroxynonenal on c-myc expression.
The 4-hydroxynonenal aldehyde (HNE), a product of lipid peroxidation with high biological activity, inhibits cancerous growths in vivo and in vitro. The mechanism by which this aldehyde acts is not yet understood. The c-myc oncogene seems to be involved in the regulation of cellular multiplication and transformation. We evaluated the c-myc expression and the RNA, DNA and protein synthesis in K562 cells. These cells were incubated for 1 hour in presence of several aldehyde concentrations (range 5.10(-7) to 10(-4)), then washed and kept for 20 hours in a growth medium until used. HNE inhibited both the nucleic acids and protein synthesis in a dose dependent manner, and c-myc expression was evaluated in the K562 cells after incubation with 10(-4) M or 10(-6) M HNE. HNE inhibited c-myc expression only at the highest dose. These preliminary results may suggest that the inhibition of c-myc expression is related to nucleic acid synthesis inhibition following HNE exposure.
Aldehydes↗
Immunopharmacological studies of PTT.119, a new synthetic bis-(2-chloroethyl)amino-L-phenylalanine derivative.
The new synthetic tripeptide p-F-Phe-m-bis-(2-chloro-ethyl)amino-Phe-Met-etoxy HCl, PTT.119, was studied for its effects on the host immune system. Doses of PTT.119 ranging from 3 to 18 mg/kg were administered i.p. to recipient mice which, at different times after drug treatment, were tested for allograft response, competence in producing lymphocytes active in lethal graft-versus-host disease, delayed-type hypersensitivity, mitogen responsiveness, humoral antibody production and natural resistance against microbial infections. At therapeutically active dosages, PTT.119 appeared to selectively inhibit functions mediated by B lymphocytes, leaving the majority of those involving T-cell subsets largely unaffected, even at the highest doses employed. Moreover, drug treatment had also a limited impact on the in vivo resistance of mice to microbial infection, which was only affected by a drug injection of 18 mg/kg, a dose well within the confidence limits of the mean lethal dose of the drug.
Animals↗
Nasopharyngeal carcinoma: the diagnostic value of the antibody-dependent, cellular cytotoxicity test and of EBV serology.
In the present study we report the results of the EBV-specific antibody response in 30 Italian NPC patients, 20 other head and neck tumor patients and 20 healthy controls. Histopathologically, the tumors were classified as squamous cell carcinoma (WHO 1), nonkeratinizing carcinoma (WHO 2) and undifferentiated carcinoma (WHO 3). Immunofluorescence tests were performed in order to evaluate the antibodies against VCA, EA and the EBV nuclear antigen (EBNA), and the antibody dependent cellular cytotoxicity test was used to detect the EBV specific antibodies against membrane antigens. IgG and IgA antibodies to EBV VCA and IgG antibodies to EA were significantly and consistently higher in the NPC patients than in other patients or controls. Moreover, only the WHO 2 and WHO 3 histological types of NPC resulted associated with EBV. ADCC titers ranging from 1:480 to 1:15360 have been determined; low ADCC titers were prevalent among the VCA-IgA positive donors, while VCA-IgA negative donors presented high ADCC titers. Our results look consistent with other previous results in low-risk and high-risk areas. In conclusion, EBV serology seems to be extremely useful for diagnostic purposes; however, in order to assess a prognostic value of the above markers, a greater number of patients followed for a longer period is needed.
Antibodies, Viral↗
Subcellular and extracellular localization of specific binding sites for triphenylethylene antiestrogens in human breast cancer.
MCF-7 human breast cancer cell homogenates and subcellular organelles were submitted to isopycnic centrifugation on Percoll gradients to investigate the subcellular localization of triphenylethylene antiestrogen specific binding sites (AEBS). Electron microscopy revealed that gradient fractions coincident with the migration of [3H]tamoxifen-AEBS complexes were homogeneously represented by rough and smooth endoplasmic reticulum. Eighty percent of AEBS were localized in the endoplasmic reticulum [45,000 +/- 4,000 sites/cell, mean +/- S.D.), while 20% of these sites were also found in the nuclear fraction (12,000 +/- 1,000 sites/cell, mean +/- S.D.). A similar subcellular distribution of AEBS was observed in human breast cancer bioptic specimens. No differences in [3H]tamoxifen binding affinity between microsomal and nuclear AEBS were observed in MCF-7 and bioptic breast cancer. No major differences in microsomal AEBS levels were observed in the limited number of estrogen receptor-positive or -negative breast cancer specimens we have studied, whereas estrogen receptor-negative samples had higher levels of nuclear AEBS with respect to estrogen receptor-positive tumors. The presence of AEBS was also detected in the human serum of healthy and tumor-bearing subjects. The affinity and the binding specificity of serum AEBS were similar to those of intracellular AEBS. No differences in the levels of serum AEBS were observed between healthy and tumor-bearing subjects [19 +/- 4 and 22 +/- 4 pmoles/ml (mean +/- S.D.) respectively. Human serum AEBS did not appear to be associated to lipoproteins, whereas it migrated as a 5.5 S sedimenting molecule.
Binding Sites↗
Sequential metabolic events and morphological changes during in vivo large granular lymphocyte activation and proliferation.
Interferon (IFN) and IFN inducers are known to boost natural killer (NK) activity in vivo and in vitro. In vivo enhancement of NK activity results from activation of preexisting NK cells as well as from an increased number of large granular lymphocytes (LGL), with a portion of them undergoing cell division. Our study was addressed to analyze the sequence of metabolic events occurring within the LGL population of Fischer rats treated with poly(I:C), as an IFN inducer. The increase in cytotoxic activity and LGL number in the peripheral blood already reached maximal levels by 12 hr after poly(I:C) injection, remained on a plateau 24 to 48 hr later, then slightly decreased on Day 4, and returned to control levels by Day 6. A similar kinetics was observed for RNA synthesis. In contrast DNA synthesis first increased at 24 hr, peaked at 48 hr, then decreased on Day 4, and was not detectable on Day 6. Percoll fractionation resulted in 92-97% of LGL in fraction 1, and cells in this fraction accounted for the increase of cytotoxicity as well as for newly synthesized RNA and DNA. However, LGL recovered on Day 1 or 2 after poly(I:C) stimulation displayed quite heterogeneous morphology, and a number of mitotic configurations were seen on Day 2 within the LGL population. Our results indicate that the boosting of NK activity by poly(I:C) is always associated with an increase in LGL numbers, the enhanced lytic capacity is associated in vivo with new RNA synthesis by the NK cells, and only in a later phase NK cell proliferation may account for the increase in LGL numbers.
Animals↗
HTLV-I and HIV infection in drug addicts in Italy.
Explore the source record for details and available documents.
Antibodies, Viral↗
Structure-activity relationships of calmodulin antagonism by triphenylethylene antiestrogens.
Explore the source record for details and available documents.
3',5'-Cyclic-AMP Phosphodiesterases↗
Calcium modulation activates Epstein-Barr virus genome in latently infected cells.
In many viral infections the host cell carries the viral genome without producing viral particles, a phenomenon known as viral latency. The cellular mechanisms by which viral latency is maintained or viral replication is induced are not known. The modulation of intracellular calcium concentrations by calcium ionophores induced Epstein-Barr viral antigens in lymphoblastoid cell lines that carry the virus. When calcium ionophores were used in conjunction with direct activators of protein kinase C (12-O-tetradecanoyl phorbol-13-acetate and a synthetic diacylglycerol), a greater induction of viral antigens was observed than with either agent alone. Activation of protein kinase C may be required for the expression of the viral genome.
Aminoquinolines↗
In vitro effect of thymosin alpha 1 on the expression of peanut agglutinin binding by murine thymocytes.
Thymosin alpha 1 induces the loss of PNA binding ability by subpopulation of thymic cells. This loss is probably due to an endocytic process. Nevertheless this disappearance is not a permanent one, suggesting a recycling of the PNA binding molecule. The cells that modulate their PNA binding sites after exposure to Thymosin alpha 1 are a small proportion of the total PNA+ thymocytes, indicating that not all thymocytes are susceptible to the thymic hormone Thymosin alpha 1. Conversely the exposure of thymocytes to Thymosin alpha 1 induces the disappearance of the binding sites for this ligand without further recycling, behavior expected for the receptor of a regulatory ligand. These results also indicate that the Thymosin alpha 1 and the PNA binding sites are on different molecules on the surface of the PNA+ thymocytes.
Animals↗
Studies on the mechanism of low natural killer cell activity in infant and aged mice.
NK activity in mice is high between about 6 and 10 weeks of age. In contrast, infant mice and mice older than 12-14 weeks of age usually have quite low or undetectable NK activity. Studies were performed to analyze the mechanisms underlying this characteristic age-related regulation of NK activity. Spleen cells from infant mice did not develop appreciable NK activity upon incubation for 12-18 h with either interferon (IFN) or interleukin-2 (IL-2). Analysis of the frequency of IL-2-dependent progenitors of NK cells, in a limiting dilution assay, also indicated that the spleens of infant mice are deficient in precursors of NK cells. In contrast, spleen cells from old mice (30 weeks old) developed substantial levels of NK activity upon incubation with either IFN or IL-2, and they showed a frequency of IL-2-dependent progenitors of effector cells that was similar to that of young mice. Both infant and old mice had plastic-adherent suppressor cells in their spleens, which could strongly inhibit NK activity. In addition, both infant and old mouse spleen cells contained nonadherent suppressor cells, which had a higher density on Percoll gradients than NK cells. Thus, several factors appear to contribute to the age-related regulation of NK activity in mice.
Age Factors↗
Calmodulin antagonism and growth-inhibiting activity of triphenylethylene antiestrogens in MCF-7 human breast cancer cells.
The triphenylethylene antiestrogen tamoxifen has been shown previously to inhibit both calmodulin and protein kinase C activities, which are involved in the control of cell proliferation. We have studied the effect of several derivatives of the triphenylethylene antiestrogen family on the inhibition of both calmodulin-dependent cyclic adenosine 3':5'-monophosphate-phosphodiesterase activity and proliferation of breast cancer cells cultured with 0.5 microM estradiol in order to prevent interaction of these drugs with the estrogen receptor. We have observed that hydroxylation of the triphenylethylene molecule significantly decreases its ability to inhibit the calmodulin-dependent phosphodiesterase activity in vitro. Furthermore, the growth-inhibiting activity of several antiestrogens and other calmodulin antagonists [R24571, trifluoperazine, N-(6-aminohexyl)-5-chloronaphthalene-1-sulfonamide, and N-(6-aminohexyl)-1-naphthalenesulfonamide] correlated with their antagonistic effects on calmodulin activity. The level of activity was determined as follows: R24571 greater than tamoxifen = N-demethyltamoxifen = nafoxidine greater than 4-hydroxytamoxifen greater than 3,4-dihydroxytamoxifen = trifluoperazine greater than N-(6-aminohexyl)-5-chloronaphthalene-1-sulfononamide greater than metabolite A greater than N-(6-aminohexyl)-1-naphthalenesulfonamide. On the other hand both protein kinase C-activating and -inhibiting drugs (phorboltetradecanoate-13-acetate and tamoxifen, respectively) have a synergistic inhibitory effect on the growth of MCF-7 cells. Our data suggest that antiestrogen interactions with calmodulin and not protein kinase C may play a role in mediating the drug-induced estrogen-independent inhibition of breast cancer cell growth.
3',5'-Cyclic-AMP Phosphodiesterases↗
Prostaglandin-induced storage and secretion of esteroproteases in the mouse submaxillary gland.
The submaxillary glands of adult C3H mice which received intraperitoneal injections of prostaglandins F2 alpha and E2 (PGF2 alpha and PGE2) were examined biochemically and ultrastructurally. Results indicated that the specific activity of esteroprotease in an homogenate of submaxillary glands was significantly increased when mice were treated with PGF2 alpha (96 or 480 micrograms/kg), and decreased when they were treated with PGE2 (96 or 480 micrograms/kg). Ultrastructural findings were correlated with these biochemical data. Thus, it appeared that PGF2 alpha stimulated the secretion and synthesis of bioactive proteins, and that PGE2 stimulated only the secretion.
Animals↗
An in vitro assay for evaluating chemosensitivity of leukaemia cells: preclinical studies.
The present study was aimed at defining the standard conditions for predictive chemosensitivity testing of human leukaemias. The in vitro cytotoxic potential of 11 anticancer drugs against L1210 murine leukaemia was comparatively determined 3 and 48 h after in vitro exposure of leukaemia cells to these agents. In preliminary testing, drug-induced damage was estimated in terms of percent inhibition of: tumour cell proliferation, by microscopic determination of viable cell numbers; and DNA synthesis, by measuring the extent of incorporation of the labelled nucleoside 125IUdR. Since the two tests appeared to yield comparable results, all subsequent experiments on the various murine tumours were performed using the radiolabel incorporation technique. The results obtained pointed out that this metabolic assay performed 48 hours after drug exposure appears to be capable of predicting both "spontaneous" and "induced" in vivo resistance of murine leukaemias.
Animals↗
Receptors for thymosin alpha 1 on mouse thymocytes.
Thymosin alpha 1 is able to act in vitro to stimulate T-cell precursors and to induce surface markers. The initial mechanism by which alpha 1 activates T cells could be the binding of alpha 1 to cell membranes. Using a specific anti-alpha 1 antibody and an indirect immunofluorescence procedure it was found that thymosin alpha 1 binds to the surface of a large portion of murine lymphocytes. Furthermore, thymocytes have been fractionated into immature and mature subpopulations by using the peanut agglutinin (PNA) technique. It was found that PNA+, immature cells showed specific receptors for alpha 1 on the cell membrane.
Animals↗
Estrogen receptors and estrogen sensitivity of fetal thymocytes are restricted to blast lymphoid cells.
We have observed [3H]estradiol binding sites in the cytosol of lymphoid cell suspensions obtained from the fetal thymus of guinea pig. Scatchard analysis [dissociation constant (Kd), 0.5 +/- 0.02 (SE) nM], binding specificity, and diethylaminoethyl chromatography of these [3H]estradiol binding sites are similar to those described for estrogen receptors. Estrogen receptor levels in the thymic lymphoid cell population have been studied after fractionating cells by Percoll discontinuous density gradients into large and low density cells (alpha-cells) and small and high density cells (beta-cells). Estrogen receptor levels are higher in alpha-cells [1002 +/- 200 (SE) sites per cell] than beta-cells [61 +/- 6 (SE) sites per cell]. Electron microscopy shows that the ultrastructural characteristics of 95% alpha-cells are consistent with their lymphoblastoid nature, whereas 90% of the beta-cells represented here can be categorized as typical small lymphocytes. To study whether cellular estrogen receptor expression was related to blastogenesis, fetal thymocyte suspensions were cultured throughout 48 h in the presence of the mitogen Concanavalin A. A significant increase in estrogen receptor levels was observed in thymic lymphoid cells cultured in the presence of the mitogen [1500 +/- 193 (SE) sites per cell] with respect to cells cultured in the absence of the mitogen [400 +/- 54 (SE) sites per cell]. One-day and 3-day in vivo estrogen treatments decrease significantly the [3H]thymidine uptake [by 40 +/- 1% (SE) and 66 +/- 5% (SE), respectively], the mitotic index [by 82 +/- 8% (SE) and 96 +/- 2% (SE), respectively] and the frequency of lymphoblastoid cells [by 15 +/- 4% (SE) and 50 +/- 2% (SE), respectively] in fetal thymocyte suspensions. A 29 +/- 0.7% (SE), 31 +/- 0.8% (SE), and 35 +/- 2% (SE) decrease of [3H]thymidine incorporation in the DNA of alpha-cells cultured throughout 24 h, 48 h, and 72 h, respectively, in the presence of estradiol (10 nM) was observed with respect to untreated alpha-cells (P less than 0.01), while no effect of estradiol was observed on [3H]thymidine uptake by beta-cells. The mitotic index of cultured alpha-cells was significantly decreased [by 67 +/- 5% (SE)] 48 h after the addition of estradiol to the culture medium. It is concluded that: 1) estrogen receptors and estrogen sensitivity are restricted to lymphoblastoid thymic cells, and 2) estrogen receptor levels are increased after lymphoid blast transformation.
Animals↗