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F P Gasparro

Publications and source records attributed to F P Gasparro.

At least 19 recordsLinked to original sources
PubMed1992

Retinoid augmentation of bioactive interleukin-1 production by murine keratinocytes.

The effect of retinoids on the production of interleukin-1 (IL-1) by murine epidermal keratinocytes was investigated. Freshly isolated keratinocytes were cultured in the presence of etretinate, acitretin, all-trans retinoic acid or 13-cis retinoic acid at concentrations of 8 x 10(-9)-8 x 10(-6) mol/l. Exposure of keratinocytes to retinoids increased IL-1 bioactivity in culture supernatants and cell extracts at concentrations as low as 8 x 10(-9) mol/l, as assessed by T-cell proliferation. Prolongation of the culture period enhanced the augmentative effect of retinoids. All-trans retinoic acid and 13-cis retinoic acid had a greater ability to induce IL-1 production than the two aromatic retinoids, etretinate and acitretin. Treatment with 8-methoxypsoralen plus ultraviolet A radiation and treatment with triamcinolone acetonide both reduced the effect of retinoids on the production of bioactive IL-1.

Acitretin↗
PubMed1992

8-MOP vs 5-MOP.

Explore the source record for details and available documents.

5-Methoxypsoralen↗
PubMed1992

DNA associated with the cell membrane is involved in the inhibition of the skin rejection response induced by infusions of photodamaged alloreactive cells that mediate rejection of skin allograft.

Cell membrane DNA (cmDNA) is a form of DNA located on the surface of human and murine T-cells. It has recently been characterized as a target for photomodification by 8-methoxypsoralen (8-MOP) and long-wave ultraviolet light (UV-A). Whereas 8-MOP itself is biologically inert, photoactivated 8-MOP is covalently bound to pyrimidine bases in DNA. We have investigated the possible involvement of cmDNA photomodification in the induction of the suppression of skin allograft rejection in BALB/c mice preimmunized with 8-MOP/UV-A photodamaged alloreactive cells which mediates this allograft rejection. This suppression is demonstrated by inhibition of delayed-type hypersensitivity (DTH) and mixed leukocyte culture (MLC) responses. Splenocytes from BALB/c mice undergoing rejection of CBA/j skin graft which contained an expanded population of the effector T lymphocytes that mediate the rejection were treated with DNAse to remove cmDNA before or after treatment with 8-MOP and UV-A prior to infusion into naive BALB/c recipients. Mice that received pretreated effector cells were tested for MLC responses to CBA/j or B10 alloantigens before and after the DTH response. The DTH response of all groups of pretreated BALB/c mice to the relevant alloantigen was specifically suppressed as compared with the response of control mice. However, adoptive transfer of the suppression of the DTH response was optimally demonstrable only in syngeneic recipients of cells from donor mice treated with photodamaged alloreactive cells. Also, splenocytes from BALB/c mice immunized with photodamaged alloreactive cells demonstrated highly significant hyporesponsiveness and suppression of the MLC response of naive mice to the relevant alloantigen in the case of the primary MLC response, and to both alloantigens in the secondary MLC response which was totally eliminated by prior pretreatment of these effector cells with DNAse. Therefore, it appears that the suppression of the DTH response can be induced by pretreatment of the effector cells with DNAse and/or 8-MOP and UV-A but is adoptively transferable optimally only from mice which are recipients of photodamaged alloreactive cells. Moreover, the effectiveness of this treatment is decreased by prior removal of cmDNA from these cells. The presence of cmDNA is necessary for induction of suppression of the primary and secondary MLC responses in mice treated with photodamaged cells of allograft rejection.

Animals↗
PubMed1992

Extracorporeal photochemotherapy for cutaneous T-cell lymphoma and other diseases.

Extracorporeal photochemotherapy is an effective method for the treatment of CTCL. It is most effective in the erythrodermic stages of the disease but may also have a place in the treatment of more advanced disease. Phototherapy has also been used in the treatment of other T-cell-mediated diseases. Psoralen plus UVA are known to interact with cellular DNA, proteins, and lipids. The mechanism of action is not completely understood but there is suggestive evidence that cell membrane changes so caused can render the cell susceptible to immune surveillance and destruction.

AIDS-Related Complex↗
PubMed1991

Photoactivatable antisense DNA: suppression of ampicillin resistance in normally resistant Escherichia coli.

Antisense oligodeoxyribonucleotides complementary to a segment of the beta-lactamase gene and containing psoralen monoadducts at specific sites were examined for their ability to make normally resistant bacteria sensitive to ampicillin. Irradiation of oligonucleotides and psoralens with long-wavelength ultraviolet radiation (380-400 nm) produced monoadducted antisense molecules. High-performance liquid chromatography was used to purify microgram quantities of photoactivatable antisense DNA. Escherichia coli transformed with a plasmid containing the gene for beta-lactamase were used to test a series of oligonucleotides containing psoralen monoadducts after additional exposure to the photoactivating effects of long-wavelength ultraviolet radiation (320-400 nm). Normally resistant bacteria treated with this photoactivatable form of antisense DNA (0.4 microM) were specifically sensitized to ampicillin. The reduction in colony formation ranged from 31 to 79% in comparison to control oligonucleotides which did not contain photoactivatable monoadduct moieties. Bacteria treated in a similar manner but in the presence of tetracycline instead of ampicillin were not affected. The activity of beta-galactosidase, whose gene is located on the same plasmid as beta-lactamase, was not affected.

Ampicillin Resistance↗
PubMed1991

Formation and removal of 8-MOP-DNA photoadducts in keratinocytes: effects of calcium concentration and retinoids.

8-methoxypsoralen (8-MOP)-DNA photoadducts were quantified in freshly isolated human and murine keratinocytes and cultured keratinocyte cell lines after in vitro treatment with 8-MOP (1-200 ng/ml) and ultraviolet A (UVA; 0.2-24.0 J/cm2). Greater doses of 8-MOP and UVA led to proportionately greater numbers of photoadducts, with a dose reciprocity relationship between the amounts of 8-MOP and UVA. No significant difference in photoadduct formation was observed between basal and differentiated cells. However, the transformed keratinocyte cell lines showed fewer photoadducts than did normal keratinocytes, which appeared to be correlated with the finding that the adduct formation was inhibited in normal keratinocytes cultured with phorbol 12-myristate 13-acetate, because this agent leads to epidermal hyperproliferation. In viable keratinocytes that were treated with a sublethal dose of 8-MOP and UVA (15 ng/ml and 1 J/cm2, respectively), 54% of photoadducts formed were removed over a 20-h period. Adduct removal depended on the calcium concentration in the media; cells cultured in standard high calcium levels showed a higher removal rate than those cultured in low-calcium media. The addition of retinoids (etretinate, acitretin, and 13-cis retinoic acid) to the culture induced 55 to 80% of suppression of the adduct removal. The calcium ionophore A23187 partially restored the suppression of photoadduct removal induced by retinoids. The present studies suggest that calcium performs an important role in the photoadduct removal and raise the possibility that the synergism of systemic retinoids and psoralen plus UVA photochemotherapy relates to the former's inhibition of repair of 8-MOP photoadducts in DNA.

Adrenal Cortex Hormones↗
PubMed1991

High-performance liquid chromotography analysis of 8-methoxypsoralen monoadducts and crosslinks in lymphocytes and keratinocytes.

Human lymphocytes and murine keratinocytes were treated with clinically relevant doses of 8-methoxypsoralen and long-wavelength ultraviolet radiation. The extent of 8-MOP photoadduct formation was determined by liquid scintillation analysis. The distribution of photoadducts was determined by HPLC analysis of enzymatically hydrolyzed DNA from these cells. Analysis of photoadduct formation in lymphocytes and keratinocytes showed that 4',5'-monoadducts were the predominant photoadducts (42% and 41%, respectively). Monoadduct and crosslink yields were dependent on cell type as well as irradiating wavelength. The photochemical conversion of 400 nm-induced 4',5'-monoadducts to crosslinks, as well as 3,4-monoadducts in poly(dA-dT), was measured.

Animals↗
PubMed1991

Quantitation of plasma levels of 8-methoxypsoralen by competitive enzyme-linked immunosorbent assay.

An immunologic method for the quantitation of 8-methoxypsoralen (8-MOP) levels in human plasma has been developed. A monoclonal antibody recognizing 8-MOP was prepared by immunizing mice with an 8-MOP derivative conjugated to bovine serum albumin with 1-ethyl-3-(3-dimethylamino-propyl)-carbodiimide-HCl. The antibody was characterized by competitive enzyme-linked immunosorbent assay (ELISA) and recognizes 8-MOP (50% inhibition at 2 pmol) as well as structurally related psoralen derivatives including 4'-aminomethyl-4,5',8-trimethylpsoralen (50% inhibition at 50 pmol), 5-methoxypsoralen (50% inhibition at 150 pmole), and 6,4,4'-trimethylangelicin (50% inhibition at 360 pmol). The assay has a limit of sensitivity of 1 ng/ml plasma. For analysis of 8-MOP levels in plasma, samples were first extracted using SepPak C18 cartridges. The extracts were analyzed for 8-MOP levels both by ELISA and high-pressure liquid chromatography. There was a good correlation between the values determined by both methods (r = 0.92, p less than 0.0005). The development of immunologic methods should greatly facilitate the quantitation of 8-MOP levels in patient plasma.

Animals↗
PubMed1991

Inhibitory effect of 8-methoxypsoralen plus ultraviolet-A on interleukin-1 production by murine keratinocytes.

We report the effects of 8-methoxypsoralen (8-MOP) plus ultraviolet-A (UV-A) irradiation on interleukin-1 (IL-1) production by murine epidermal keratinocytes, correlating its effect on IL-1 with cell viability, DNA synthesis, and 8-MOP-DNA photoadduct formation. Freshly isolated murine keratinocytes were treated with various doses of 8-MOP (5-100 ng/mL; incubation time, 30 min) plus 1 J/cm2 UV-A and cultured for 1-3 days. The IL-1/epidermal cell-derived thymocyte-activating factor (ETAF) activity in both supernatant and cell extract was reduced proportionately with increasing doses of 8-MOP/UV-A. Interleukin-1 inhibitors induced by 8-MOP plus UV-A were not detected in either supernatant or cell extract. A clear reduction of the IL-1 production was induced by the treatment as low as 15 ng/mL 8-MOP plus 1 J/cm2 UV-A, which led to the formation of 0.52 8-MOP photoadducts per million DNa bases and affected neither cell viability nor DNA synthesis of the treated cells. Cells treated with 100 ng/mL 8-MOP and 1 J/cm2 UV-A exhibited 57% suppression of IL-1 production in both 2- and 3-day culture samples. This treatment resulted in the formation of 3.8 photoadducts per million bases as well as significant abrogation of DNA synthesis although cell viability was unchanged. These observations provide some insights into the phototoxicity mechanisms of 8-MOP and the effect of PUVA therapy on the cytokine regulation in keratinocytes.

Animals↗
PubMed1990

Cell membrane DNA: a new target for psoralen photoadduct formation.

The effects of 8-methoxypsoralen plus long wavelength ultraviolet radiation on cell membrane DNA were examined. Treatment of human lymphocytes with 100 ng/ml 8-methoxypsoralen and 5 J/cm2 UVA led to the formation of 7.1 +/- 3.8 photoadducts per million bases. A monoclonal antibody, specific for 8-methoxypsoralen 4',5'-monoadducts, was used to detect photoadducts in the cell membrane DNA of human lymphocytes and three lymphoblastoid cell lines. Treatment of lymphocytes with 8-MOP and UVA reduced the lymphocyte DNA binding capacity by 56%. Cell membranes of normal lymphocytes were shown to contain three high affinity DNA binding proteins of 28, 59, and 79 kDa, respectively.

Cell Line↗
PubMed1989

6,4,4'-trimethylangelicin photoadduct formation in DNA: production and characterization of a specific monoclonal antibody.

The photochemical reactions of 6,4,4'-trimethylangelicin (TMA) with calf thymus DNA and an octanucleotide containing a single thymine have been characterized. HPLC analyses of enzymatically hydrolyzed TMA-DNA showed that isomeric forms of 4',5'-furan-side monoadducts were the major products. To develop monoclonal antibodies Balb c mice were immunized with the TMA-DNA complexed with methylated bovine serum albumin. The resultant antibodies were characterized by enzyme-linked immunosorbent assays (ELISA). The most sensitive antibody (7E3) has high specificity for TMA-DNA, very low cross-reactivity with DNA modified with either 4',5'-dimethylangelicin or 4'-methylangelicin and no cross-reactivity with non-modified DNA or with DNA modified with either 4'-aminomethyl-4,5',8-trimethylpsoralen or 8-methoxypsoralen. To characterize further this antibody, oligonucleotides containing specific TMA photoadducts were isolated from the photoreaction mixture by polyacrylamide gel electrophoresis and used as competitive inhibitors in the ELISA. Autoradiography of the gel showed an intense band corresponding to the 4',5'-monoadduct and two weaker unidentified bands. Antibody 7E3 reacted only with the 4',5'-monoadduct band as would be expected since this photoadduct was the principal photoadduct in the original antigen.

Antibodies, Monoclonal↗
PubMed1989

8-Methoxypsoralen-DNA adducts in patients treated with 8-methoxypsoralen and ultraviolet A light.

The combination of 8-methoxypsoralen (8-MOP) plus ultraviolet A light (320-400 nm), termed PUVA, is used in the treatment of psoriasis, a hyperproliferative disease of the skin. This treatment results in the formation of specific 8-MOP adducts with cellular DNA. We have previously developed monoclonal antibodies which recognize these 8-MOP photoadducts. We now report the use of these antibodies in an indirect immunofluorescence technique to study human skin biopsies. Nuclei in 3 of 5 skin biopsies from psoriasis patients undergoing PUVA therapy were positive for adducts. The presence of adducts by immunofluorescence did not correlate with plasma levels of 8-MOP. Enzyme-linked immunosorbent assays, used to determine whether 8-MOP photoadducts could be detected in DNA isolated from the lymphocytes of psoriasis patients after PUVA therapy, were negative.

Antibodies, Monoclonal↗
PubMed1988

Preparation and characterization of biotinylated psoralen.

Biotinylated psoralen (BPsor), a psoralen derivative containing a biotin moiety attached via a long-chain, positively charged linker, has been synthesized and its interactions with DNA and avidin have been studied. As do other psoralen derivatives, BPsor photoreacts with DNA to form interstrand crosslinks. The biotin binds to streptavidin after the reaction of BPsor with DNA, and this property has been used to measure low levels of BPsor modified DNA by ELISA with streptavidin and biotinylated alkaline phosphatase. In addition, BPsor retains the biological activity of psoralen, as shown by its ability to inhibit lymphocyte proliferation at a level of 10 ng/ml.

Biotin↗
PubMed1988

The effects of gilvocarcin V and ultraviolet radiation on pBR322 DNA and lymphocytes.

The antitumor antibiotic gilvocarcin (GV) when photoactivated with UV radiation induced single strand breaks in superhelical pBR322 DNA. The optimal wavelengths for nicking DNA correlated with the absorbance maximum of GV near the visible region (398 nm). The response of lymphocytes to stimulation by phytohemagglutinin was reduced to 10% of controls at 0.10 ng/ml GV in combination with 3 J/cm2 of ultraviolet A (UVA) radiation. The potency of gilvocarcin is attributed to two factors: its strong tendency to intercalate with DNA (K = 6.6 X 10(5) M-1) and its intense absorption of UVA radiation (E398 = 11971 M-1 cm-1).

Aminoglycosides↗