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S Colonna

Publications and source records attributed to S Colonna.

18 recordsLinked to original sources
PubMed1992

Mechanism of enantioselective oxygenation of sulfides catalyzed by chloroperoxidase and horseradish peroxidase. Spectral studies and characterization of enzyme-substrate complexes.

The binding of a series of alkyl aryl sulfides to chloroperoxidase (CPO) and horseradish peroxidase (HRP) has been investigated by optical difference spectroscopy, circular dichroism, paramagnetic NMR spectroscopy, and NMR relaxation measurements. The data are consistent with binding of the sulfides in the distal side of the heme pocket with CPO and near the heme edge with HRP. A linear correlation between the binding constants of para-substituted sulfides to CPO and the Taft sigma I parameter suggests that these substrates act as donors in donor-acceptor complexes involving some residue of the protein chain. Spectral studies during turnover show that high enantioselectivity in the CPO-catalyzed oxidation of sulfides results from a reaction pathway that does not involve the accumulation of compound II enzyme intermediate.

Catalysis↗
PubMed1992

Cutaneous melanoma and sunburns in childhood in a southern European population.

A population-based case-control study of 260 patients (74 males and 186 females, mean age = 56) with cutaneous malignant melanoma and 416 controls (211 males and 205 females, mean age = 55) was conducted in Turin, north-west Italy, to examine the relation between timing of sunburns and sun exposure and melanoma risk within a southern European population, which is still relatively little investigated. Particularly elevated risk was associated with history of sunburns in childhood [odds ratio 5.9; 95% confidence interval (CI) 3.6-9.5], and such risk elevation persisted after allowance for other major melanoma risk covariates. Conversely, risk increase from history of severe sunburns lifelong was lower (odds ratio = 1.7; 95% CI: 1.1-2.4) and was eliminated by allowance for type of skin reaction to sun exposure and history of sunburns in childhood. A significant increase in the risk of cutaneous malignant melanoma was also associated with number of weeks spent on holiday at the beach not only as an adult, but also as a child.

Adolescent↗
PubMed1991

Oxidation of cysteine to cysteic acid in proteins by peroxyacids, as monitored by immobilized pH gradients.

It has often been debated whether the presence of persulfate in a polyacrylamide gel could lead to the oxidation of cysteine (Cys) in proteins to cysteic acid. In fact, direct incubation of bovine serum albumin (BSA) with peroxodisulfate and periodate barely alters the isoelectric point (pI) and does not produce any cysteic acid. In contrast, caroate (peroxomonosulfate) and perphthalate strongly lower the pI of BSA. In the former case it as demonstrated that 4-Cys (of a total of 35) were converted into cysteic acid. Perphthalate was found to be, by far, the strongest oxidant: 15 (of 35) Cys residues were oxidized to cysteic acid and all methionine groups were destroyed.

Ammonium Sulfate↗
PubMed1990

Enantioselective oxidations of sulfides catalyzed by chloroperoxidase.

The chloroperoxidase-catalyzed and horseradish peroxidase catalyzed oxidations of sulfides by tert-butyl and other peroxides have been investigated. The former metal enzyme afforded the corresponding sulfoxides having R absolute configuration in up to 92% enantiomeric excess (ee), whereas the latter gave racemic products. The various factors that control the enantioselectivity of the oxygenation have been examined.

Chloride Peroxidase↗
PubMed1990

Cutaneous malignant melanoma in females: the role of hormonal and reproductive factors.

The role of hormonal and reproductive factors as risks for cutaneous malignant melanoma (CMM) was explored by means of a population-based case-control study conducted in Turin, north-western Italy, on 186 female CMM cases and 205 controls. Past use of oral contraceptives (OC) did not seem to exert any effect on CMM risk odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.56-2.24). No association was found even for the longest duration of use, for superficial spreading melanoma cases and for CMM of lower limbs only. While age at first birth did not affect CMM risk, women who had had three or more children seemed to be significantly protected as compared to nulliparous ones. The association was, however, substantially diminished by adjustment for education and other CMM risk correlates (OR for at least three children versus none = 0.62; 95% Cl: 0.29-1.31).

Adolescent↗
PubMed1990

[Acquired melanocytic nevus. Epidemiologic clinical study of a healthy population].

Total body naevi counts have been performed on 3931 Italian subjects aged 5 to 79 years (2063 males and 1868 females). Only naevi greater than or equal to 2 mm in diameter were recorded. The total mean naevi count was 15 (15 for males, 14 for females); in the first decade of life the count was 8, rising rapidly in the second decade to a mean of 18 and was 22 in the third decade. Thereafter the frequency of naevi declined with age; in the eight decade the number was similar to that seen in children. The association between total naevi count and place of birth of subjects or their parents was not significant. The frequency of naevi varied according to body site: the most common site was the trunk (6 naevi), the next most affected site was the upper arm (4 naevi). Distribution by eye colour, hair colour and number of naevi showed an increase in subjects with blue or green eyes and red or fair hair. High associations were found between large numbers of acquired melanocytic naevi and pale skin. Skin types 1 and 2 had a higher melanocytic naevi count than skin types 3 and 4.

Adolescent↗
PubMed1988

[A case-control study of melanoma of the skin in the province of Torino, Italy].

A population based case-control study was conducted in the province of Torino (Northern Italy) where internal migration produced a population with mixed ethnicity and lifestyles. Two hundred and eight cases of histologically confirmed cutaneous malignant melanoma (CMM) and four hundred and sixteen controls were interviewed. Our results gave evidence to the role of skin reaction to the sun (OR 5.0 in men and 2.2 in women) as an indicator of a group at risk. The increased risk of intense and occasional sun exposure as can be inferred from sun exposure during holidays and outdoor sports, has been confirmed (OR 4.1 in men and 2.7 in women). Ethnic differences did not play an important role in our population, women who used oral contraceptives also did not show an increased risk.

Contraceptives, Oral↗
PubMed1976

[Mesenteric cysts. Clinical case].

A case of multiple mesentery cysts is presented and the etiopathogenesis, anatomopathology, symptomatology and therapy of this disease discussed.

Child↗
PubMedDate not supplied

Ultrasonic vocalization in rat pups as a marker of behavioral development: an investigation of the effects of drugs influencing brain opioid system.

Early postnatal exposure to morphine significantly influenced the ultrasonic vocalization of rat pups removed from their nest. In particular, a significant decrease in the rate of calling, sound pressure level and range of frequency was found in morphine-treated animals; moreover, the duration of calls was significantly increased by morphine administration. Conversely, neither beta-casomorphins (beta CMS), which are opioid peptides derived from the enzymatic digestion of milk protein (beta-casein), nor an opioid antagonist, like naloxone, significantly affected ultrasonic emission. The results are discussed with particular reference to the role of the opioid system in separation distress-induced vocalization in young animals.

Aging↗