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Biomedical subjects

V Maresca

Publications and source records attributed to V Maresca.

At least 19 recordsLinked to original sources
PubMed2002

Polyunsaturated fatty acids of germ cell membranes, glutathione and blutathione-dependent enzyme-PHGPx: from basic to clinic.

The lipid metabolism in sperm cells is important both for energy production and for cell structure. A special composition of membrane phospholipids, rich in polyunsaturated fatty acids (PUFA), and the different composition of sperm and immature germ cell membrane are described and discussed. Testis germ cells as well as epididymal maturing spermatozoa are endowed with enzymatic and non-enzymatic scavenger systems to prevent lipoperoxidative damage. Catalase, superoxide dismutase, and glutathione-dependent oxidoreductases are present in variable amounts in the different developmental stages. Phospholipid hydroperoxide glutathione peroxidase (PHGPx) activity and roles in caput and cauda epididymal sperm cells are discussed. Also seminal plasma has a highly specialized scavenger system that defends the sperm membrane against lipoperoxidation and the degree of PUFA insaturation acts to achieve the same goal. Systemic predisposition and a number of pathologies can lead to an anti-oxidant/pro-oxidant disequilibrium. Scavengers, such as glutathione can be used to treat these cases as they can restore the physiological constitution of PUFA in the cell membrane.

Animals↗
PubMed2001

Mitochondrial impairment in peripheral blood mononuclear cells during the active phase of vitiligo.

Several hypotheses have been made about the pathogenesis of vitiligo, and some of them have considered a systemic involvement in the course of the disease. Evidence has been presented on the role of oxidative stress as the initial event in melanocyte degeneration. In accordance with this view, we determined the levels of some antioxidants, i.e., superoxide dismutase, catalase, reduced glutathione, and vitamin E, in erythrocytes and/or peripheral blood mononuclear cells from patients with active or stable vitiligo and from a control group of healthy subjects. In erythrocytes the parameters evaluated were not significantly different. On the contrary, in peripheral blood mononuclear cells, superoxide dismutase activity was increased in both groups of patients, whereas catalase activity, reduced glutathione and vitamin E levels were decreased exclusively in subjects with active disease. The imbalance of antioxidants was associated with hyperproduction of reactive oxygen species due to a mitochondrial impairment as cyclosporin A, an inhibitor of the permeability transition pores opening, significantly reduced the reactive oxygen species production. Moreover an alteration of the mitochondrial transmembrane potential and a higher percentage of apoptotic cells were observed in active vitiligo patients. Based on these results, we suggest that, in vitiligo, mitochondria might be the target of different stimuli, such as reactive oxygen species generation, cytokines production, catecholamine release, alteration of Ca2+ metabolism, all of which capable of inducing melanocyte degeneration.

Adult↗
PubMed2001

A pilot study on the relation between cisplatin neuropathy and vitamin E.

Peripheral sensory neuropathy is the main non-hematological side-effect related to cisplatin chemotherapy. The strong similarity between clinical and neuropathological aspects in peripheral neuropathy induced by cisplatin and neurologic syndromes due to vitamin E deficiency, prompted us to investigate the relationship between cisplatin neuropathy and plasmatic level of vitamin E (alpha-tocopherol). We measured vitamin E in the plasma of 5 patients (Group 1) which developed severe neurotoxicity after cisplatin treatment and in another group of 5 patients (Group 2) we analyzed the plasmatic level of vitamin E before and after 2 or 4 cycles of cisplatin treatment. The results showed that the patients of group 1 presented low plasmatic levels of vitamin E and that the patients of group 2 presented significantly lower levels of vitamin E after 2 or 4 cycles of cisplatin than before treatment. Our preliminary data suggest that an inadequate amount of the antioxidant vitamin E due to cisplatin treatment could be responsible of the peripheral nerve damage induced by free-radicals. Given the lack of toxicity of vitamin E, we need to systematically assess the possible neuroprotective role of vitamin E supplementation in patients treated with cisplatin chemotherapy.

Adult↗
PubMed2000

Fatty acid composition of spermatozoa and immature germ cells.

A great deal of attention has recently been given to the essential role of polyunsaturated fatty acids (PUFA) of sperm membranes. We studied the fatty acid composition of the immature germ cells (IGC) and of the sperm populations separated by Percoll gradient in the ejaculate of normozoospermic patients. Fatty acid pattern was analysed by combined gas chromatography-mass spectrometry on a capillary column. In IGC, differences were found compared with mature spermatozoa, with a higher percentage of saturated fatty acids and of essential fatty acids. On the contrary, the long-chain PUFA were significantly lower in IGC. The highest concentration of n3 PUFA docohexaenoic acid (DHA) was detected in the spermatozoa deriving from 70-100% Percoll layers and a direct linear correlation was found between the increase of DHA and increased percentage of Percoll gradient. An inverse relationship between the percentage of atypical sperm forms in each layer and the percentage of DHA was also observed. This study demonstrates that the human germ cell line can elongate and desaturate essential fatty acids and that the percentage of long-chain PUFA is correlated with the normal morphology of sperm cells.

Fatty Acids↗
PubMed1999

Antioxidant pattern in uveal melanocytes and melanoma cell cultures.

PURPOSE: To investigate the antioxidant status of cultured uveal melanocytes from patients with uveal melanoma and uveal melanoma cells to characterize some of the biochemical properties of these cells in respect to the normal cutaneous melanocytes. METHODS: The fatty acid pattern of membrane phospholipids, intracellular vitamin E level, and superoxide dismutase (SOD) and catalase activities were studied in uveal melanocytes (n = 10) and uveal melanoma cell (n = 10) cultures, by gas chromatography mass spectrometry or by spectrophotometer. RESULTS: Among the uveal melanocyte cultures, two groups were differentiated, according to catalase activity: group A with catalase values comparable to those of cutaneous ones and higher SOD activity and group B with catalase values 2 SD lower (P<0.001) and lower SOD activity. Vitamin E concentration was not significantly different between melanoma cells and melanocytes, whereas a significantly higher percentage of polyunsaturated fatty acids was found in melanoma cells and the B group of melanocytes (P = 0.022). In uveal melanoma cells SOD activity was significantly lower than that detected in uveal melanocytes (P< 0.005). CONCLUSIONS: These results show a different pattern of antioxidants in uveal melanocytes with respect to cutaneous ones, possibly related to the anatomic distribution. However, as in cutaneous melanocytes, two subgroups were identified on the basis of the antioxidant pattern that could be the expression of a constitutional increased susceptibility to oxidative stress in some subjects. Moreover, an imbalance of the antioxidants was observed in melanoma cells, possibly related to the disease status and progression.

Adult↗
PubMed1999

The reconstructed epidermis with melanocytes: a new tool to study pigmentation and photoprotection.

The reconstruction of the epidermal melanin unit ex vivo has been achieved during the last decade, using the combination of previous cell culture techniques. The system reviewed is basically a modification of the Pruniéras model, using the air-liquid interface to grow differentiated keratinocytes, with the addition of 5% melanocytes in the seeding suspension, as well as the use of a more adapted culture medium. Repeated UVB irradiation induces a stimulation of melanogenesis macroscopically, and increases melanin concentration and melanosome transfer in reconstructs. These results have been reproduced with skin of various phototypes. This model allows to study the physiology of the epidermal melanin unit as well as pathologic conditions, like vitiligo and nevi. Recent evidence of a complex interaction of keratinocytes and melanocytes in photoprotection was provided by the use of chimeric reconstructs and by comparing autologous reconstructs made with and without low phototype caucasoid melanocytes. Based on these findings, we suggest a novel interpretation of the concept of phototype.

3T3 Cells↗
PubMed1998

Chimeric human epidermal reconstructs to study the role of melanocytes and keratinocytes in pigmentation and photoprotection.

Chimeric epidermal reconstructs made with Negroid melanocytes and Caucasoid keratinocytes (or vice versa) were studied before and after UVB irradiation to understand the respective roles of these cells in tanning and photoprotection, especially lipoperoxidation and enzymatic defences against free radicals. Using this approach, we have confirmed overall the theory of the epidermal melanin unit. We have also shown that melanocytes of poorly tanning Caucasoids, which have a comparatively higher content of unsaturated fatty acids in their cell membrane, are more prone to the peroxidative effects of UV light, and that keratinocytes participate in photoprotection via phototype-dependent antioxidant enzyme activities, especially for catalase.

Adult↗
PubMed1998

Increased sensitivity to peroxidizing agents is correlated with an imbalance of antioxidants in normal melanocytes from melanoma patients.

We have previously shown an imbalance of the antioxidant system in some cultures of normal melanocytes from patients with melanoma. In order to evaluate if the alteration of the antioxidants could be the basis of an increased sensitivity to exposure to peroxidative agents, in cultured melanocytes from normal individuals (n = 11) and from patients with melanoma (n = 11), superoxide dismutase and catalase activities were evaluated by spectrophotometer, and the levels of vitamin E and of the polyunsaturated fatty acid of cell membranes were determined by gas chromatography mass spectrometry. In 5 out of the 11 cultures of melanocytes from melanoma patients, with respect to those from normal individuals, a significant decrease of catalase activity (Cat) associated with an increase of vitamin E (Vit E) concentration was found, whereas no significant modification of superoxide dismutase activity (SOD) was observed. A wide range of variability was detected in the percentage of the polyunsaturated fatty acids of the cell membranes and a correlation was found between the ratio SOD/Cat and the percentage of linoleic acid, indicating that the imbalance of the enzymatic antioxidants leads to a lipoperoxidative process. The electron microscopic examination of these cultures revealed many microvilli in the plasma membranes and nuclear infoldings and in the cytoplasm light vacuoles. Moreover some cells contained several dense bodies with a round shape and numerous spherical lamellae possibly representing immature melanosomes. Treatment with cumene hydroperoxide between 0.66 and 20 microM did not produce a significant modification of cell viability in melanocytes from normal individuals. On the contrary in melanocytes from melanoma patients correlated with the ratio Vit E/Cat, considered as a parameter of the antioxidant imbalance, a stimulatory effect was observed at 0.66 microM CUH and a cytotoxic effect at 20 microM. In conclusion our results suggest that a constitutional alteration of the scavenger system could be present in normal melanocytes from melanoma patients and that this could be the basis for an increased sensitivity to pro-oxidant agents.

Adult↗
PubMed1997

Increased sensitivity to peroxidative agents as a possible pathogenic factor of melanocyte damage in vitiligo.

To examine the sensitivity of vitiligo melanocytes to external oxidative stress, we studied enzymatic and non-enzymatic anti-oxidants in cultured melanocytes of normal subjects (n = 20) and melanocytes from apparently normal skin of vitiligo patients (n = 10). The activity of superoxide dismutase and catalase and the intracellular concentrations of vitamin E and ubiquinone were evaluated in cultures at the fourth or fifth passage. In addition, cells were exposed to various concentrations of a peroxidizing agent, cumene hydroperoxide (CUH, 0.66-20 microM), for 1 and 24 h. Compared to normal melanocytes, vitiligo melanocytes showed normal superoxide dismutase and significantly lower catalase activities and higher vitamin E and lower ubiquinone levels. At the concentration used, CUH did not significantly affect cell number or viability of melanocytes after either period of culture. On the contrary, vitiligo melanocytes were susceptible to the toxic effect of CUH after 24 h of continuous treatment at concentrations greater than 6.6 microM. The degree of CUH toxicity correlated strictly with the anti-oxidant pattern, defined as the ratio between vitamin E concentration and catalase activity, suggesting that the alteration in the antioxidants was the basis for sensitivity to the external oxidative stress. Our results demonstrate the presence of an imbalance in the anti-oxidant system in vitiligo melanocytes and provide further support for a free radical-mediated damage as an initial pathogenic event in melanocyte degeneration in vitiligo.

Adult↗
PubMed1995

Protease inhibitors block apoptosis at intermediate stages: a compared analysis of DNA fragmentation and apoptotic nuclear morphology.

The possible correlation between DNA digestion and changes in nuclear morphology in apoptosis was studied by blocking the apoptotic process at intermediate stages. The apoptogenic action of three drugs: etoposide, puromycin, tributyltin, was contrasted with protease inhibitors with different specificity on U937 cells. The inhibitors interfered with the development of the apoptotic features without shifting cell death to necrosis: treated cells showed abnormal morphologies, which could be recognized as intermediate stages of apoptosis; accordingly, DNA analysis showed an inhibitor-dependent block of the apoptotic DNA digestion. The comparison between size of DNA fragments and nuclear morphology suggested the following correlations: loss of normal nuclear shape with the appearance of a > or = 2 Mb DNA band; ongoing chromatin condensation with the progressive DNA digestion up to 50 kb; nuclear fragmentation with DNA laddering. Protease inhibitors in etoposide-treated cells did not allow the formation of 700-300 kb fragments, suggesting that they possibly derive from a cell-mediated effect.

Apoptosis↗
PubMed1995

Non-oxidative loss of glutathione in apoptosis via GSH extrusion.

Reduced glutathione (GSH) has been hypothesized to play a role in the rescue of cells from apoptosis, by buffering an endogenously induced oxidative stress. We correlated GSH levels and apoptosis in U937 human monocytic cells induced to apoptosis by different agents. All treatments led to depletion of GSH concomitant with the onset of apoptosis. The loss was due to extrusion of GSH outside the cell, while GSSG was not accumulated in the apoptosing cells, nor was it found in the extracellular medium. Modulation of intracellular GSH level did not influence the overall extent of apoptosis. We conclude that glutathione loss in apoptosis is not necessarily preceded by an oxidative stress, and that GSH depletion alone is not sufficient to lead cells to apoptosis.

Antimetabolites, Antineoplastic↗
PubMed1995

Different basal NAD levels determine opposite effects of poly(ADP-ribosyl)polymerase inhibitors on H2O2-induced apoptosis.

We have recently described that poly(ADP-ribosyl)-polymerase (PARP) inhibitors rescue U937 cells from apoptosis induced by 1 mM H2O2 oxidative stress; PARP activation leads to a reversible drop in NAD level, which could be blocked by PARP inhibitors (Nos-seri et al., 1994, Exp. Cell Res. 212, 367-373). A phenotypic variant of U937 is characterized by a lower basal NAD level (low NAD, LN U937, as opposed to the original high NAD, HN U937). In LN cells treatment with 1 mM H2O2, although activating PARP, does not lower NAD concentration; puzzlingly, PARP inhibitors increase (instead of decreasing, as occurs in HN cells) the extent of stress-induced apoptosis, leading to a reduced cell survival. NAD concentration could be increased in LN cells by adding nicotinamide (5-and 25-fold increase) to the culture medium. These cells (LN+) behaved as HN U937: oxidative stress induced a NAD drop, the extent of which is dependent on the cells' basal NAD level; moreover, PARP inhibitors could rescue LN+ cells from peroxide-induced apoptosis. H2O2-induced apoptosis is not triggered by NAD depletion, but instead it takes place only when NAD levels have been preserved or have recovered: on HN U937, peroxide doses (5 and 10 mM) which lead to necrosis induce an irreversible NAD drop, whereas apoptosis occurs only at lower doses, where NAD depletion is reversible; on LN cells NAD levels do not drop even upon 10 mM H2O2 treatment, and these cells die only by apoptosis; moreover, in HN cells apoptosis is not detectable until 8 h posttreatment, when NAD levels recover, whereas in LN cells, where NAD is always present, apoptosis begins to take place as early as 3 h after stress.

Apoptosis↗
PubMed1995

The increase in H2O2-induced apoptosis by ADP-ribosylation inhibitors is related to cell blebbing.

HN and LN are two phenotypic variants of the U937 monocytic cell line which differ in their basal NAD content; they respond in an opposite way to oxidative stress in the presence of the poly(ADP-ribosyl)polymerase (PARP) inhibitors 3-aminobenzamide (3ABA) and nicotinamide (NA): the inhibitors protect HN cells from stress-induced apoptosis, while they enhance it on LN cells (Coppola et al., 1995, Exp. Cell Res. 221, 462-469). These opposite effects are due to two overlapping and contrasting phenomena occurring in LN cells, as shown by the bi-modal response of stressed LN cells to increasing 3ABA doses. Indeed H2O2-induced apoptosis is enhanced only at high 3ABA concentrations (i.e., sufficient to inhibit also mono-ADP-ribosylations); lower 3ABA concentrations, which specifically inhibit PARP, also protect LN U937 from stress-induced apoptosis. Unlike HN U937, H2O2-induced apoptosis in LN cells is accompanied by cell blebbing. High 3ABA doses strongly enhance blebbing, leading to cellular fragmentation. Blebbing could be blocked by interfering with actin polymerization with cytochalasin B and D: this eliminated the increase in apoptosis due to 3ABA, suggesting that it is indeed the consequence of excess blebbing. This is supported by the unusual finding that in U937 LN stressed in the presence of 3ABA or NA, blebbing, usually a late event in apoptosis, may even precede its onset.

ADP Ribose Transferases↗
PubMed1991

Effects of parenteral diclofenac sodium on upper gastrointestinal motility after food in man.

In experimental animal models nonsteroidal anti-inflammatory drugs may influence gastrointestinal motility, but as evidence is lacking in man. The effect of diclofenac sodium 75 mg i.m. on the motor response of the upper gastrointestinal tract to food has been studied by manometry in 9 healthy volunteers. Diclofenac had no effect on the motor activity of the stomach, duodenum, or jejunum after a 605 kcal meal.

Adult↗
PubMed1991

Intranasal and intramuscular human calcitonin in female osteoporosis and in Paget's disease of bones: a pilot study.

It has been shown that human calcitonin (hCT) is absorbed through the nasal mucosa when administered together with promoters like sodium glycocholate (SGC) or dihydrofusinate. The aim of this study was to compare the clinical and metabolic effect of intranasal (in) and intramuscular (im) hCT in patients with osteoporosis or with Paget's disease of bones. Fifteen women with postmenopausal or with senile osteoporosis entered a randomized six months trial with in hCT (plus SGC) or with im hCT 100 U on alternate days. Six women in each group were treated for 2 months, and only four women in each group continued treatment for an additional 4 months period. In hCT, but not im hCT, reduced subjective pain, while urinary cAMP increased to a similar extent in the 2 groups. Other metabolic indexes and bone mineral content (BMC) were unchanged, no new fractures took place, and side effects were fewer with in than with im hCT. To confirm the analgesic effect of in hCT, twelve patients with Paget's disease of bone were randomly treated for 20 days with in or im hCT 100 U/day: during the short period of treatment, pain was reduced by in, not by im hCT, and urinary cAMP excretion similarly increased in the two groups of patients.

Administration, Intranasal↗
PubMed1989

Transdermal estradiol in the treatment of postmenopausal bone loss.

The effects on calcium metabolism and forearm bone mineral density of sequential transdermal estradiol (ESTRADERM TTS-50), 50 micrograms/day and medroxyprogesterone (10 mg/day for 12 days) was studied in a randomised controlled trial in 34 healthy females 2-4 years after the menopause. At the end of the 18 months' treatment course with transdermal estradiol, bone density was increased by 4.31% (P less than 0.01) but was decreased by 3.5% (P less than 0.01) in the control group. In the treated group, serum calcium, calcium excretion and hydroxyproline excretion significantly fell during the first 2 months with no significant changes thereafter. Serum alkaline phosphatase significantly decreased only after 4 months, it continued to fall until the fourteenth month when a plateau became apparent. Serum phosphate and tubular maximum for urinary phosphate progressively fell until the tenth month of therapy but thereafter they rose up to initial values. Serum intact parathyroid hormone did not show any significant change. In conclusion, small doses of transdermal estradiol are as effective as oral estrogens. This suggests that the bone sparing effects of estrogens may be due only to low circulating estradiol concentrations, but not to supraphysiological estrone levels. It seems also that estrogens exert both a straight inhibition of bone resorption and a partial inhibition of parathyroid responsiveness.

Administration, Cutaneous↗
PubMed1989

Cefroxadine in the treatment of children affected by respiratory and ENT diseases. A multicentre study involving 1072 in-patients.

In this multicentre trial, 1072 hospitalized children, 573 boys and 499 girls (847 of whom were aged less than 6 years), affected by respiratory tract (376 patients) or ENT (696 patients) infections were treated for 10 days with cefroxadine per os, at an average dose of 650 mg/day (325 mg every 12 h corresponding to 25 mg/kg b.w.). Most patients (1047; 97.7%) completed the trial, while 25 patients were withdrawn from the study (20 patients for viral diseases and 5 for side-effects). Of the patients affected by respiratory tract infections, 361 completed the trial and 342 of them (94.7%) were cured in 6.0 days on average. Of the patients affected by ENT infections, 686 completed the trial and 649 of them (94.6%) were also cured in an average of 6.0 days. In the two groups the signs and symptoms of the disease significantly (p less than 0.001) decreased by the end of the study. Some patients (80; 7.6%) complained of side-effects, mainly gastric discomfort (4.9%), skin rash (2.2%) and glossitis (0.5%). In conclusion, cefroxadine exerts a satisfactory antibacterial action with only a few days of treatment, and it appears to be very well tolerated.

Bacterial Infections↗