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Biomedical subjects

G Moreno

Publications and source records attributed to G Moreno.

At least 91 records · Page 5Linked to original sources
PubMed1985

Cytotoxic effects following micro-irradiation of cultured cells sensitized with haematoporphyrin derivative.

Haematoporphyrin derivative photosensitization has been studied in single heart cells in tissue culture by laser micro-irradiation (lambda = 632.8 nm). Changes of beating rate as well as cell death depend on the localization of the microbeam on the various parts of the cell. The results show that the targets for photodamage are the plasma membrane followed by the mitochondria.

Animals↗
PubMed1984

Effects of the mitochondrial probe rhodamine 123 and related analogs on the function and viability of pulsating myocardial cells in culture.

Rhodamine 123, a cationic fluorescent dye, has previously been shown to specifically localize in or on mitochondria in living cells. Since it has also been shown to be relatively non-toxic in a variety of cell types it has been a useful tool for probing mitochondria in vitro. In this report, using cardiac cells in culture, we demonstrate that rhodamine 123 and 6G both positively charged compounds, quickly inhibit beating and kill cardiac-muscle cells while uncharged or neutral rhodamines, 116 and B, produce neither effect. We also present data which illustrate that the cationic rhodamines inhibit oxidative phosphorylation in isolated mitochondria while the neutral dyes do not. It is suggested that both phenomena may be related.

Animals↗
PubMed1983

Effects of photodynamic action on energy coupling of Ca2+ uptake in liver mitochondria.

In mitochondria isolated from rat liver, incubated in the presence of 6 X 10(-3) mM hematoporphyrin and irradiated with UV light at 365 nm, respiration, oxidative phosphorylation and Ca2+ uptake were measured in order to determine the respective photosensitivity of these functions. Irradiation with increasing doses produces uncoupling of oxidative phosphorylation followed by inhibition of Ca2+ uptake and finally arrest of respiration. Ca2+ uptake stimulated by the addition of ATP was also studied in mitochondria uncoupled by irradiation which were still able to concentrate Ca2+ aerobically. Anaerobic Ca2+ uptake driven by ATP hydrolysis was found to be similar in control and in irradiated mitochondria, suggesting a different photosensitivity for the ATPase as compared to the ATP-synthase activity.

Animals↗
PubMed1982

Penetration and localization of furocoumarins in single living cells studied by microspectrofluorometry.

The microspectrofluorometric technique has been used to study the penetration and the localization of psoralen, 4,5',8-trimethylpsoralen and 4'-aminomethyltrioxsalen in single living L-cells. The concentration of the different compounds inside the cell reached a plateau in 2 min with psoralen and aminomethyltrioxsalen and in 20 min with trioxsalen. Washing of the cells with culture medium produced only a partial removal of the three furocoumarins, distributed apparently in equivalent amount in the nucleus and cytoplasm.

Animals↗
PubMed1981

Autoradiographic localization of 8-methoxypsoralen in psoriasis skin in vitro.

Slices of psoriatic (Pso) skin were incubated with tritiated 8-methoxypsoralen (8-MOP) and exposed to UVA irradiation. The photobinding of 8-MOP was studied by autoradiography at the cellular level and in the different layers of the epidermis and in the dermis. Silver grains were found in the nucleus and the cytoplasm of the various cell types. Keratin, collagen and lipoproteins were also labelled. The upper malpighian cells and the parakeratotic cells showed a greater degree of labelling than did the basal layers. In skin incubated with [3H]8-MOP and unirradiated, no measurable labelling was detected. These results suggest that the targets responsible for the therapeutic activity of 8-MOP might be not only nucleic acids, but also proteins.

Autoradiography↗
PubMed1980

Survival, DNA synthesis and ribosomal RNA transcription in monkey kidney cells treated by formaldehyde.

Separate cultures of CV-1 cells were exposed for 15 min to 1-16 mM formaldehyde (FA) at various time intervals before labeling with [3H]uridine. The labeled RNA extracted from whole cells was analyzed by polyacrylamide gel electrophoresis. Results indicated that FA produced transcription-terminating lesions in DNA which depressed RNA synthesis, gave rise to shortened RNA chains and modified the expression of transcription-linked genes. These lesions were efficiently repaired since a recovery of RNA transcription, with disappearance of the initially observed alterations, rapidly occurred during post-treatment incubation of cells. Cycloheximide (5 micrograms/ml) strongly inhibited this recovery, whereas fluorodeoxyuridine (10(-5) M) was without effect. The rate of semi-conservative DNA synthesis, measured autoradiographically by thymidine incorporation, as well as the number of cells performing DNA replication, fell to zero after 15-min exposure to FA concentrations greater than 2 mM. Both parameters recovered subnormal levels during a 24-h incubation after treatment with FA concentration up to 8 mM, in agreement with the high survival observed. Unscheduled DNA synthesis was not detectable during the restoration of DNA and RNA synthesis.

Animals↗
PubMed1979

Herpes virus production as a marker of repair in ultra-violet irradiated human skin cells of different origin.

Confluent cultures of human skin fibroblasts were irradiated with ultra-violet light 0 to 48 hours before infection with herpes simplex virus type 1 (HSV). The one-cycle viral yield was measured. Different responses were obtained according to the origin of the host cells. (1) Cells from three normal donors showed a dose-dependent recovery of HSV production during the 36--40 hours following U.V. exposure. The recovery was maximal for a dose at which a plateau level of unscheduled DNA synthesis (UDS) was reached (24 Jm-2). (2) In a xeroderma pigmentosum (XP) heterozygote line from a mother of XP children, the level of UDS after irradiation up to 48Jm-2 was normal whereas the extent of recovery of HSV production capacity was lower than that of the normal lines. (3) In strains from two cases of XP children, with a normal UDS (XP variants), the recovery process was slowed down and its extent was lower than in normal or XP heterozygote cells. (4) Excision-deficient XP strains from eight cases of XP children presented either no recovery (two strains having the lowest UDS, less than 2 per cent) or a small recovery, the extent of which was in good agreement with the corresponding level of UDS (between 5 and 30 per cent). Measurement of this recovery seems to be a very sensitive assay for detecting differences in the repair abilities of U.V.-irradiated human skin cells of various origins.

Cells, Cultured↗
PubMed1978

UV-induced unscheduled DNA synthesis in guinea pig skin melanocytes isolated in culture.

Pigmented melanocytes isolated in culture from the epidermis of guinea pig ears were used to study the unscheduled DNA synthesis (UDS) induced by ultraviolet (UV) irradiation at 254 nm. After irradiation, the cells were labeled for 6 hr with 3H-thymidine (3HTdR), fixed, dehydrated, and flat embedded in Epon. Radioautographs were made on serial 0.5-1 micrometer thick sections of the cultures in order to distinguish silver grains from pigment granules. Cells irradiated with 5, 10, or 50 joules (J) m-2 showed a 3HTdR uptake due to UDS, whereas their proliferative ability, measured by the 3HTdR uptake due to scheduled DNA synthesis, was very low. For the same UV doses, UDS was lower in melanocytes than in guinea pig fibroblasts and keratinocytes.

Animals↗
PubMed1978

Herpes virus production as a marker of repair in ultraviolet irradiated human skin cells of different origin.

When confluent human skin cultures are ultraviolet (UV)-irradiated before infection with Herpes Simplex type 1 virus (HSV), their capacity to support virus growth is impaired. When the time interval between UV-exposure and infection is increased up to 36 hours, different recoveries of HSV production capacity are observed according to the origin of the host cells. 1) Two normal donors: the cells present a dose dependent recovery which is maximal for a dose ( : formula: (see text) at which a plateau level of unscheduled DNA synthesis (UDS) is reached. 2) A mother of two Xeroderma Pigmentosum (XP) children: in this line which exhibits a normal level of UDS, the extent of recovery is significantly decreased after exposures : formula: (see text) 3) An XP child: these cells have a normal level of UDS (XP variant) whereas they present a low extent of recovery as compared with that of the normal subjects. 4) Five XP children: in these excision deficient lines (UDS less than 15%), HSV production capacity decreases with increasing time intervals after UV exposure for doses greater than or equal to 3 : formula: (see text). For doses less than 3 : formula: (see text), a small recovery with an overshoot of viral production is observed 24 h after UV exposure in the lines (three) which present the highest UDS (10--15%) and not in the two lines which present a very low UDS (1--2%).

Adult↗