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C De Luca

Publications and source records attributed to C De Luca.

At least 19 recordsLinked to original sources
PubMed1992

Paraphenylenediamine, a contact allergen, induces oxidative stress and ICAM-1 expression in human keratinocytes.

In an investigation of the role of keratinocytes in the pre-immunological phase of contact allergy, we have studied the effect of paraphenylenediamine (PPD) on cell proliferation, membrane lipid peroxidation and the expression of the intercellular adhesion molecule 1 (ICAM-1). Because PPD undergoes rapid autoxidation in the culture medium, the effect of PPD-modified medium on keratinocyte proliferation and ICAM-1 expression was also examined. PPD at low concentrations (up to 10 micrograms/ml) and with low exposure times (0.5 h) enhanced keratinocyte proliferation, but at high concentrations and with longer exposure times resulted in cell stasis and toxicity. These effects and the enhanced membrane lipid peroxidation that was also observed can be ascribed to the production of superoxide and hydrogen peroxide by the autoxidation of PPD in the medium. At non-cytotoxic concentrations, PPD induced ICAM-1 expression on the keratinocytes. PPD-modified medium was also cytotoxic to the keratinocytes and induced ICAM-1 expression in non-cytotoxic concentrations. It appeared that superoxide and hydrogen peroxide were not responsible for the cytotoxicity. These results are consistent with the view that oxidative stress may be an essential part of the pre-immunological phase in the induction of allergic contact dermatitis.

Allergens↗
PubMed1991

Role of skin surface lipids in UV-induced epidermal cell changes.

Ultraviolet irradiation is capable of affecting skin surface lipids, especially squalene and cholesterol, both in vitro and in vivo, with generation of active lipoperoxides. The photodecomposition of the skin lipid component was carefully evaluated by capillary gas-chromatography. The effects of UV-induced lipoperoxides on human keratinocytes in culture and on guinea pig ear slices were compared with those of synthetic lipoperoxides, i.e. cumene hydroperoxide and 13-hydroperoxylinoleate. A time- and dose-dependent effect on protein synthesis and mitotic activity was observed. In cell culture low concentrations (0.05-5 micrograms/ml) of peroxidated squalene and synthetic lipoperoxides stimulated the incorporation of radiolabelled thymidine and phenylalanine, while higher concentrations (greater than 10 micrograms/ml), or longer periods of treatment, induced cellular damage. In guinea pig ear slices, the lipoperoxides (5-50 micrograms/ml) increased aminoacid incorporation and the number of epidermal pigment cells; higher concentrations (greater than 100 micrograms/ml) caused a derangement of epidermal structure. The results suggest that UV irradiation of skin generates lipoperoxides from the surface lipids which, in vitro, are capable of producing a number of changes in epidermal cells.

Adult↗
PubMed1991

Skin surface lipids in HIV sero-positive and HIV sero-negative patients affected with seborrheic dermatitis.

Skin surface lipids of patients affected with seborrheic dermatitis both HIV sero-negative (C group) and HIV sero-positive (B group) have been studied by capillary Gas chromatography-Mass spectrometry (GC-MS) in comparison with normal age matched controls (A group) to determine whether, among the three groups of individuals, there were qualitative and quantitative changes in lipid class composition and in the fatty acid and alcohol components of lipid fractions. With regard to percent composition of skin surface lipid fractions, no significant differences were found between HIV sero-positive and HIV sero-negative patients with seborrheic dermatitis. The observed significant reduction of total lipids (micrograms/sq cm) in the sites affected with the disease in comparison with controls was associated with a slight but significant decrease of squalene (P less than 0.05) and with a corresponding increase of cholesterol and cholesterol esters (P less than 0.05). These abnormalities in lipid fractions and total lipids were not observed in the uninvolved skin of subjects with seborrheic dermatitis. Fatty acid and alcohol patterns of skin lipid fractions were not significantly different among the three groups of individuals.

Adult↗
PubMed1991

Blood levels of vitamin E, polyunsaturated fatty acids of phospholipids, lipoperoxides and glutathione peroxidase in patients affected with seborrheic dermatitis.

Plasma levels of vitamin E (Vit E) and polyunsaturated fatty acids of phospholipids (PUFA-PL) as well as erythrocyte glutathione peroxidase (GSH-Px) activity are significantly lower (P less than 0.001) in patients with seborrheic dermatitis (SD). both HIV seropositive or HIV sero-negative, than in control subjects. No differences are found between HIV sero-positive and sero-negative individuals with SD. The deficiency of PUFA-PL (mainly C20: 3 n-6, C20: 4 n-6 and C22: 6 n-3) which is accompanied by a significant increase of saturated palmitic and stearic acids (P less than 0.001), does not appear to be associated with an active lipoperoxidative process in the plasma. The significant blood deficiency of Vit E, GSH-Px, and particularly of PUFA-PL, may play a pathogenetic role in seborrheic dermatitis.

Adult↗
PubMed1991

The oxyradical-scavenging activity of azelaic acid in biological systems.

We have previously shown that azelaic acid, a C9 dicarboxylic acid, as disodium salt (C(9)2Na) is capable of inhibiting significantly the hydroxylation of aromatic compounds and the peroxidation of arachidonic acid due to reactive hydroxyl radicals (HO.). In this paper we have investigated the ability of C(9)2Na to inhibit the oxyradical induced toxicity towards two tumoral cell lines (Raji and IRE1) and normal human fibroblasts (HF). Oxyradicals were generated either by the addition of polyphenols to the medium, or by direct irradiation of phosphate buffered-saline in which cells were incubated from 15 min prior to incubation in normal medium. The effects of C(9)2Na were compared with those obtained by mannitol (MAN), superoxide dismutase (SOD) and catalase (CAT). C(9)2Na, MAN, SOD and CAT significantly decreased the polyphenol toxicity towards cell lines cultured up to 24 h. After 48 h of incubation the above compounds lost the capability of protecting cells from polyphenol toxicity. This suggests that the toxic role of oxyradicals (O2-., H2O2, HO.) persists for about 24 h and, subsequently other toxic mechanisms must be involved, which are not affected by oxyradical scavengers. SOD and CAT did not show any protective effect on UV induced cytotoxicity, while both C(9)2Na and MAN were capable of reducing significantly the UV damage towards cell lines, even after 48 h incubation. This can be explained by the fact that UV cytotoxicity depends mainly on the generation of HO., that can be "scavenged" by C(9)2Na or MAN, but not by SOD or CAT. C(9)2Na and MAN were not significantly degraded in the period during which they afford protection against HO..

Catalase↗
PubMed1991

Scavenging activity of azelaic acid on hydroxyl radicals "in vitro".

Azelaic acid is an aliphatic dicarboxylic acid (HOOC-(CH2)7-COOH) which has recently been shown to have some practical therapeutic applications in skin diseases of different etiologies. It possesses diverse biological activities and its mechanisms of action are still under investigation. Azelaic acid, as disodium salt (C(9)2Na), at concentrations from 0.05 mM to 1.0 mM is capable of inhibiting significantly the hydroxylation of 1-tyrosine to 1-DOPA due to hydroxylradicals (HO.) produced by Fenton reaction. Similarly C(9)2Na significantly inhibits the heterogeneous photocatalytic oxidation of toluene to cresols, and the peroxidation of arachidonic acid (C20:4,n6), due to HO. formed by dissolved oxygen in the presence of UV-irradiated semiconductor TiO2 (photo-Fenton type reaction). C(9)2Na decomposition and its by-products formation are quantifiable only at high HO. concentrations. On the contrary, C(9)2Na is not a scavenger of O2-. generated by xanthine-xanthine oxidase system. Under the same experimental conditions, mannitol behaves like C(9)2Na. These data indicate that HO. scavenging capacity of C(9)2Na in vitro, and represent a useful tool for further investigations on the mechanisms of action of azelaic acid in biological systems.

Arachidonic Acid↗
PubMed1991

Squalene peroxides may contribute to ultraviolet light-induced immunological effects.

Ultraviolet (UV) irradiation is capable of producing a dose-dependent decomposition of skin surface lipids and particularly of squalene, with the concomitant generation of active lipoperoxides. The biological effects of UV-peroxidated squalene were tested, compared with those produced by synthetic lipoperoxides (cumene hydroperoxide), on some immunological parameters in vivo modified by UVB irradiation. Application of UV-peroxidated squalene as well as cumene hydroperoxide significantly inhibited the induction of contact hypersensitivity to dinitrofluorobenzene in mice, which was associated with a decrease in the number of ATPase positive cells. The effect was dose-dependent (over 40 micrograms for peroxidated squalene and over 20 micrograms for cumene) and relevant after 2 d of treatment. Down-regulation towards the applied hapten was demonstrated. The results indicate that UV-induced lipoperoxides of squalene are capable of inhibiting the induction of contact hypersensitivity in mice and suggest that, among the other photoproducts generated in humans, squalene peroxides may play a role as biochemical messengers of the biological effects of UV irradiation of the skin.

Animals↗
PubMed1990

Relative efficacies of benzodiazepine receptor agonists in affecting red nucleus electrical activity in rabbits.

The effects of benzodiazepine receptor agonists on the electrical activity of red nucleus (RN) and neocortex were studied in rabbits. Under basal conditions, 30-40 microV, 40-50 Hz waves were recorded in RN. An increase of the amplitude (Emax, 75-90 microV) was found after IV injection of flunitrazepam (ED50, 0.14 mg/kg), diazepam (ED50, 0.28 mg/kg), alpidem (ED50, 1.57 mg/kg) and zolpidem (ED50, 0.73 mg/kg). Clonazepam (ED50, 0.12 mg/kg) and Cl 218,872 (ED50, 0.63 mg/kg) were less effective. In contrast, 2-10-fold higher doses were required to induce a slight decrease of the frequency. At the level of the cortex all benzodiazepine agonists induced synchronization and spindles. The effects of diazepam (5 mg/kg IV) in both areas were antagonized by flumazenil (0.04 mg/kg IV) and bicuculline (0.2 mg/kg IV). Pentamethylentetrazole (10-30 mg/kg IV) selectively abated the effect at the level of the cortex, whereas both clonazepam (2 mg/kg IV) and beta-CCM (0.6 mg/kg IV) selectively suppressed only the effects on the RN. These results suggest that activation of benzodiazepine receptor mainly influences the RN waves amplitude. The efficacy in increasing the amplitude appears related to the reported relative efficacy of the compound in potentiating GABA responses. The possibility exists that these effects are dependent upon the partial or full agonist action of the drugs or upon their binding at distinct benzodiazepine receptor types.

Animals↗
PubMed1990

Involvement of the "peripheral" benzodiazepine receptor type (omega 3) in the tolerance to the electroencephalographic effects of benzodiazepines in rats: comparison of diazepam and clonazepam.

Rapid tolerance to the sedative effect of large doses of diazepam (10 mg/kg IV), but not of large doses of clonazepam (2 mg/kg IV) occurs in rats after 5 days of treatment on a once-a-day regimen. Electroencephalographic (EEG) studies show that such behavioral tolerance is associated with a decreased induction of spindle bursts and with an increased induction of 20-30 Hz waves (beta-like activity). Administration of clonazepam plus the agonist of the "peripheral" benzodiazepine receptor type (omega 3) Ro 5-4864 (4 mg/kg IV) for 5 days induces signs of behavioral and EEG tolerance to sedative effects of the benzodiazepine agonist. In animals treated for 5 days with diazepam plus the omega 3 antagonist PK 11195 (5 mg/kg IV), no signs of EEG and behavioral tolerance are observed. These results suggest that omega 3 type activation influences the development of rapid tolerance to the sedative effect of diazepam in rats.

Animals↗
PubMed1990

Nickel-keratinocyte interaction: a possible role in sensitization.

Normal human keratinocytes and the keratinocyte-derived cell lines NCTC 2544 and A 431, were exposed for different periods (1-5 days) to various concentrations (0.023-46.6 micrograms/ml) of nickel (Ni2+). A dose- and time-dependent inhibition of cell growth and viability was observed. Cultures exposed to 2.3 micrograms Ni2+/ml showed approximately 50% cell survival at 5 days. An increase in release of interleukin 1 by keratinocytes was detected following culture for 24 h with a Ni2+ concentration of 2.3-11.5 micrograms/ml. Short periods of incubation (30 min) with these concentrations induced an activation of lipoxygenase in leucocytes from healthy subjects, without modifying cell viability. The results suggest that the percutaneous penetration of small amounts of Ni2+ can result in damage to keratinocytes and can initiate sensitization.

Cell Division↗
PubMed1990

[Blood levels of vitamin E, polyunsaturated fatty acids of phospholipids, lipoperoxides, glutathione peroxidase activity and serological screening for syphilis and HIV in immigrants from developing countries].

Plasma levels of vitamin E (Vit E), polyunsaturated fatty acids of phospholipids (PUFA-PL), lipoperoxides as well as erythrocytes glutathione peroxidase activity (GSH-Px), were evaluated in 200 migrants coming from developing countries, some of which at high risk for serious infective diseases. HIV-1 and syphilis infections were also investigated. 114 subjects (57%) had blood levels of Vit E, PUFA-PL and GSH-Px significantly lower (p less than 0.001, p less than 0.01) than those of normal healthy individuals (n = 30), while lipoperoxides values were unchanged. 8 from this group were found to be HIV-1 positive, and 5 TPHA positive. In contrast, the remaining 86 migrants did not show any signs of infections and their blood parameters were normal enough. These results show that factors such as widespread poverty, inadequate housing, malnutrition, insufficient access to medical care, psychological stress are strictly correlated to the reduction of blood parameters which are critical for the normal cell function of mammalian cells. PUFA-PL deficiency may cause lesions likely due to faulty cellular membranes. The lack of Vit E and GSH-Px, which are considered major protective molecules against lipoperoxidation damage in vivo, has been involved in several human diseases. We suggest that low blood levels of Vit E, GSH-Px and particularly PUFA-PL may play a pathogenetic role in the onset and development of AIDS and other infections. In this connection, we have found that a deficiency of these blood parameters occurs in patients with AIDS (n = 50) and in 32% of HIV seronegative intravenous drug abusers (n = 100).

Acquired Immunodeficiency Syndrome↗
PubMed1979

Fibreoptic colonoscopy. Indications, results and complications.

Fibreoptic colonoscopy was commenced in the Edward Wilson Colon and Rectum Unit at Sydney Hospital in June, 1973. The experience of the first five years of its use is reported. Six hundred and twenty-six examinations have been performed in 568 patients. Fibreoptic colonoscopy has been of particular value in the diagnosis and treatment of colonic polyps. A total of 318 polyps were removed from 184 patients. Their distribution, size and histological features are recorded. Eight complications occurred in the 628 examinations (1.6%). There were six colonic perforations (1.2%) with one death, and two significant haemorrhages (0.4%). This incidence of complications is acceptably low, especially in view of the great benefits obtained by the patient from fibreoptic colonoscopy. The newer instruments, especially the medium length Olympus MB3 colonoscope, have greatly facilitated the examination and, combined with increasing experience, may significantly lower the incidence of complications in the future.

Adolescent↗
PubMed1979

Elective resection for diverticular disease.

A series of 119 patients undergoing elective resection for diverticular disease has been reviewed. The indications for resection were classified into two major groups--those with severe infections ("complicated" diverticulitis), comprising 58 patients, and those with minimal infections, comprising 61 patients. The majority of the resections were limited to the sigmoid colon (101 patients). Fifteen patients underwent left hemicolectomy, whilst three had total colectomy. Thirty-six patients (30%) had a proximal defunctioning stoma--18 prior to resection and 19 at the time of resection. Anastomotic defects were noted in 15 patients (12.6%), but these were of clinical significance only in eight (6.7%). There were two deaths (1.7%) and 17 wound infections (14.3%). The group classified as "complicated" diverticulitis included the great majority of the patients requiring colostomy (32 out of 37), almost all those with anastomotic defects (14 out of 15), and most of the patients who had postoperative complications.

Acute Disease↗
PubMed1979

Rectal prolapse.

One hundred and twenty-seven patients with complete rectal prolapse have been reviewed. The condition occurred more commonly in females than males (105 to 22), and at an older age in females (mean age 55 years compared with 40 years for males). Although the diagnosis is usually obvious, the importance of recognizing occult prolapse is stressed, especially in association with benign rectal ulcer, localized proctitis and colitis cystica profunda. Examination of the patient in the squatting position may assit in showing occult prolapse. Associated incontinence occurred in 33 patients (26%). Since 1971 the policy of this Unit has been to perform a Ripstein repair for complete rectal prolapse wherever possible. One hundred and two Ripstein repairs have not been performed. A minimum follow-up period of two years is available for 53 patients, of whom 50 (94%) have had their prolapse cured. Control of prolapse usually improves continence; however, seven (13%) remained incontinent despite surgery. The Ripstein repair is strongly advocated as the most effective operation for cure of complete rectal prolapse.

Adolescent↗
PubMed1979

Ileostomy reconstruction.

A study of 47 patients undergoing ileostomy reconstruction is presented. The most common indications were recession (15 patients) and a desire for a continent type of ileostomy (12 patients). Less frequent indications were stenosis (6 patients), parastomal ulceration (6 patients), prolapse (4 patients), unsatisfactory siting (3 patients), and parastomal hernia (1 patient). Refashioning of the ileostomy at the same site was possible in 17 patients, whilst repositioning at a new site was required in 30 cases. In 28 of these laparotomy was carried out to enable repositioning, but in two cases resiting was performed without laparotomy. After the original operation, reconstruction may become necessary at any time from a few months to over 20 years.

Adolescent↗
PubMed1979

The surgical treatment of anal incontinence.

This study is review of 31 patients undergoing surgery for anal incontinence. Three groups of patients are defined--those with incontinence due to trauma (nine patients), to a combination of trauma and degeneration (five patients), and to degeneration alone (17 patients). Two surgical techniques were used--either a direct repair of the anal sphincter or a postanal repair of the levator ani muscles and external sphincter (Parks operation). In the trauma group and the combined group the more common method used was a direct repair (ten patients)--five underwent a Parks operation. In the degeneration group all but one patient underwent a Parks operation. A defunctioning proximal colostomy was carried out in only four patients--all with incontinence due to trauma. Satisfactory continence was restored in 80% of these patients. Although this is a small series, the results are considered worthwhile and greater awareness and use of the above technique is recommended.

Adult↗
PubMed1978

Prophylactic administration of low-dose heparin in colorectal surgery.

A retrospective study of 192 patients operated on by three members of the Edward Wilson Colon and Rectum Unit, Sydney Hospital, was carried out. All operations performed involved dissection within the pelvis. Prophylactic administration of low-dose heparin was used for 71 of these patients. The incidences of clinical thromboembolic disease were 7 per cent in both the group receiving heparin and the other group. In slightly more than half of the patients, pulmonary emboli occurred in the absence of peripheral deep venous thrombosis. It is suggested that the source of these emboli was thrombosis arising in the pelvic veins.

Colon↗