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Biomedical subjects

E Pelle

Publications and source records attributed to E Pelle.

12 recordsLinked to original sources
PubMed1998

Protection against cigarette smoke-induced damage to intact transformed rabbit corneal cells by N-acetyl-L-cysteine.

In order to assess cigarette smoke-induced oxidative damage to intact cells, an assay was developed to measure cell detachment and protection. Due to the complex nature of cigarette smoke, which contains molecules that can interfere with conventional spectrophotometric and fluorometric biochemical assays, transformed rabbit corneal cells were radiolabeled with tritiated thymidine and then subjected to direct stream smoke. As a result, cell damage in response to the smoke from only two cigarettes could be measured in a time-dependent manner. When cells were prelabeled with N-acetyl-L-cysteine (NAC), a substrate for glutathione synthesis, a significant reduction in damage was measured. Additionally, when buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis, was incubated with cells, a reduction in the effectiveness of NAC was observed, although NAC still retained some activity. Furthermore, vitamin E conferred no protection to cells in this system nor was NAC active in a separate assay that appears to favor peroxyl radical generation. From these results we conclude that cigarette smoke damage can easily be determined at the cellular level with this technique and that NAC acted to prevent this damage in two ways: first, as glutathione precursor and, secondly, as an antioxidant capable of scavenging non-peroxyl radicals.

Acetylcysteine↗
PubMed1990

An in vitro model to test relative antioxidant potential: ultraviolet-induced lipid peroxidation in liposomes.

Since antioxidants have been shown to play a major role in preventing some of the effects of aging and photoaging in skin, it is important to study this phenomenon in a controlled manner. This was accomplished by developing a simple and reliable in vitro technique to assay antioxidant efficacy. Inhibition of peroxidation by antioxidants was used as a measure of relative antioxidant potential. Liposomes, high in polyunsaturated fatty acids (PUFA), were dispersed in buffer and irradiated with ultraviolet (UV) light. Irradiated liposomes exhibited a significantly higher amount of hydroperoxides than liposomes containing antioxidants in a dose- and concentration-dependent manner. Lipid peroxidation was determined spectrophotometrically by an increase in thiobarbituric acid reacting substances. To further substantiate the production of lipid peroxides, gas chromatography was used to measure a decrease in PUFA substrate. In order of decreasing antioxidant effectiveness, the following results were found among lipophilic antioxidants: BHA greater than catechin greater than BHT greater than alpha-tocopherol greater than chlorogenic acid. Among hydrophilic antioxidants, ascorbic acid and dithiothreitol were effective while glutathione was ineffective. In addition, ascorbic acid was observed to act synergistically with alpha-tocopherol, which is in agreement with other published reports on the interaction of these two antioxidants. Although peroxyl radical scavengers seem to be at a selective advantage in this liposomal/UV system, these results demonstrate the validity of this technique as an assay for measuring an antioxidant's potential to inhibit UV-induced peroxidation.

Antioxidants↗
PubMed1982

Chlorambucil therapy in hairy cell leukemia: effects on lipid composition and lymphocyte subpopulations.

Two patients with progressive hairy cell leukemia following splenectomy were treated with low-dose daily chlorambucil. Both had an objective hematologic response as determined by a return to normal hematocrit and platelet count. This was also reflected in the mononuclear cell fraction by the normalization of cholesterol content, cholesterol/phospholipid ratio, and the lymphocyte subpopulations. This article confirms previous reports on the efficacy of chlorambucil in this setting and describes some morphological, and biochemical concomitant events.

Aged↗
PubMed1981

Increased ascorbic acid content in chronic lymphocytic leukemia B lymphocytes.

Human lymphocyte extracts analyzed by high-performance liquid chromatography reveal a major UV-absorbing peak that was shown to be ascorbic acid by spectral, chemical, and enzymatic criteria. Because this peak appeared very prominent in the elution profile of chronic lymphocytic leukemia (CLL) lymphocyte extracts, we measured the ascorbic acid content in lymphocytes from the blood of normal subjects and untreated patients with chronic lymphocytic leukemia. A significantly higher concentration of 111 +/- 15.3 nmol per 10(8) cells (mean +/- SEM) was found in CLL lymphocytes than in normal blood lymphocytes, which contained 42.2 +/- 3.3 nmol per 10(8) cells. Selective enrichment with B and T cells showed that this difference was limited to the chronic lymphocytic leukemia B cell, which had a 5- to 15-fold higher content of ascorbic acid than normal B cells had. In contrast, the ascorbic acid level was similar in normal and CLL T cells. The very high ascorbic acid content provides the chronic lymphocytic leukemia B cell with a reducing substance that could react with oxidants or free radicals.

Ascorbic Acid↗
PubMed1981

Electrophoretic mobility distributions distinguish hairy cells from other mononuclear blood cells and provide evidence for the heterogeneity of normal monocytes.

The electrophoretic mobility distributions of hairy cells, normal monocytes. CLL, and normal lymphocytes isolated from blood were determined by electrophoretic light scattering. Values obtained for hairy cells, 1.52 X 10(-4) cm2/V . sec, were indistinguishable from that of normal monocytes. The mobility of CLL lymphocytes was similar to that of normal B cells. After exposure to neuraminidase, hairy cells revealed a homogeneous distribution with a reduced mobility of 0.55 X 10(-4) cm2/V . sec, while normal monocytes showed a heterogeneous distribution of electrophoretic mobilities suggestive of subpopulations. The electrokinetic behavior of hairy cells thus differs from that or normal and CLL lymphocytes before, and from that of monocytes after, treatment with neuraminidase. The hairy cell therefore possesses a distinct pattern of surface charge properties that clearly distinguish it from the circulating B cells, T cells, or monocytes.

B-Lymphocytes↗
PubMed1981

Comparison of lipid composition and 1,6-diphenyl-1,3,5-hexatriene fluorescence polarization measurements of hairy cells with monocytes and lymphocytes from normal subjects and patients with chronic lymphocytic leukemia.

In this report, we compare the lipid composition and fluorescence polarization properties of hairy cells with those of monocytes and lymphocytes from normal subjects and of lymphocytes from patients with chronic lymphocytic leukemia. For hairy cells, the cholesterol content was 4.66 +/- 1.49 (S.D.) mumol/10(9) cells, and the cholesterol/phospholipid ratio was 0.60 +/- 0.09. These were significantly higher than the values of normal lymphocytes, (cholesterol content, 2.75 +/- 0.65 mumol; cholesterol/phospholipid ratio, 0.50 +/- 0.07) or of chronic lymphocytic leukemia lymphocytes (cholesterol content, 1.76 +/- 0.43 mumol; cholesterol/phospholipid ratio, 0.44 +/- 0.07). Normal monocyte values (cholesterol content, 5.81 +/- 2.08 mumol; cholesterol/phospholipid ratio, 0.59 +/- 0.06) were similar to those of hairy cells. Using the probe 1,6-diphenyl-1,3,5-hexatriene, the fluorescence polarization value at 25 degrees for hairy cells was 0.302, compared to the value of 0.259 obtained with chronic lymphocytic leukemia lymphocytes. Intermediate values (0.294) were obtained with normal lymphocytes and monocytes. Fluorescence polarization values were higher in hairy cell membranes than in chronic lymphocytic leukemia lymphocyte membranes, indicating a low fluidity in the former cell, compatible with their higher cholesterol content and cholesterol/phospholipid ratio. These studies show that two neoplastic cells, hairy cells and chronic lymphocytic leukemia lymphocytes, differ markedly in membrane fluidity and that a high membrane fluidity does not necessarily occur in neoplasia.

Aged↗
PubMedDate not supplied

Protection against endogenous and UVB-induced oxidative damage in stratum corneum lipids by an antioxidant-containing cosmetic formulation.

A 16-week human clinical study was carried out to determine the ability of antioxidants in a cosmetic vehicle to inhibit the induction of lipid peroxidation in stratum corneum lipids. The study consisted of a twice daily application of material for 12 weeks followed by a 4-week regression phase. Stratum corneum lipids were collected and then exposed to 500 mJ/cm2 of ultraviolet B (UVB) radiation in order to avoid excessive erythemal damage to the subjects. Lipid peroxides were assayed by a methylene blue derivative assay and expressed per unit area of skin. During the treatment period, decreases in the level of lipid peroxides were observed on the sites treated with the compositions containing antioxidants, as compared to the untreated sites, and expressed as percent differences. Decreases were observed in endogenous as well as UV-induced lipid peroxides followed by a return to baseline levels. These results demonstrate that antioxidants in a topical cosmetic formulation were effective in protecting human stratum corneum lipids against endogenous oxidation or if challenged by 500 mJ/cm2 UVB.

Antioxidants↗
PubMedDate not supplied

Cigarette smoke-induced lipid peroxidation in human skin and its inhibition by topically applied antioxidants.

Cigarette smoke, whether indirect or direct stream, is an environmental pollutant which presents an increasing health problem. In order to determine damage to human skin at the biochemical level, volar forearms were exposed to cigarette smoke for fifteen minutes and then assayed for the presence of stratum corneum lipid peroxides. A time-dependent increase was observed over a 24-hour post-exposure period. At 24 h, the average baseline level of lipid peroxides was 14.9 nmol/unit area of skin as compared to 32.0 nmol/unit area of skin for the smoke-exposed arms. In addition, when topical antioxidants were pre-applied to the skin and then exposed to cigarette smoke, an average decrease of 40.9% in lipid peroxide values was observed. These data demonstrate that peroxidation was induced in human skin by cigarette smoke and subsequently inhibited by the presence of antioxidants.

Administration, Topical↗
PubMedDate not supplied

A test for antioxidant activity in cosmetic formulations.

The aim of this study was to develop a technique to assay for the activity of antioxidants in a finished cosmetic product. This was accomplished by adapting the Randox Assay for Total Antioxidant Status kit so that diluted samples could be evaluated by kinetic as well as end-point determinations. Using this technique, we found that a finished product had an IC(50) of 0.07 gm of product and a relative antioxidant activity concentration of 52.7 nmoles/mg.

Antioxidants↗