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G Allegri

Publications and source records attributed to G Allegri.

At least 55 records · Page 3Linked to original sources
PubMed1987

Collisional spectroscopy in structural characterization of melanins: I. A first study on [C8H7ON](+.) ions originating from pyrolysis of biosynthetic and synthetic tryptophan melanins.

The structural investigation of four bio- and synthetic melanins, obtained by the action of polyphenol oxidase from potatoes and Psalliota campestris mushrooms and of tyrosinase from Sepia officinalis on tryptophan, or by means of performic oxidation, has been carried out by thermal decomposition performed in the ion source of a mass spectrometer. The structural characterization of the ionic species [C8H7ON](+.), common and abundant for all the examined compounds, has been obtained by accurate mass measurements and collisional spectroscopy. These mass spectrometric techniques have shown unequivocally for ionic species [C8H7ON](+.) the structure of 2-indolinone.

Chemical Phenomena↗
PubMed1986

Flow cytometric analysis of liposome-nuclei interaction: transfer and intranuclear release of carboxyfluorescein.

Flow cytometric analysis of the transfer of liposome-encapsulated carboxyfluorescein to isolated rat liver nuclei indicated that the fluorophore is actively taken up in this form, while negligible amounts are transferred when the dye is free in the reaction medium. The kinetic analysis of the uptake indicated a time- and dose-dependent reduction of the slope in the absence of transport saturable sites on the nuclear surface and of quenching phenomena. The comparison between entire and membrane-deprived nuclei demonstrated that the initial rate of uptake was higher in the absence of the complete nuclear envelope. The intranuclear binding sites were considered on the basis of the fluorescence distribution and of quantitative estimates of the amount of linked dye. The possibility of employing flow cytometry to monitor the interactions between liposomes and isolated nuclei by means of a fluorescent probe is discussed.

Animals↗
PubMed1985

Levels of total and free tryptophan in maternal and in umbilical blood of infants born by vaginal delivery and by elective cesarean section.

The variations of total and free tryptophan levels in samples of maternal and umbilical blood obtained on the occasion of elective cesarean section have been compared with similar samples taken from vaginal deliveries. In the neonates studied the umbilical blood levels of total and free tryptophan have been found to be higher than in the blood of the respective mothers, while the percentage of free tryptophan is comparable. In addition, the umbilical blood levels of both fractions of tryptophan appeared to be higher in newborn infants after spontaneous delivery than in those after elective cesarean section. These data show an active transport of tryptophan through the placental barrier that seems to be favored by spontaneous delivery.

Cesarean Section↗
PubMed1984

Transfer of liposome-encapsulated carboxyfluorescein to isolated nuclei.

The interaction between phosphatidylcholine vesicles and isolated rat liver nuclei has been examined by studying the uptake of the fluorophore carboxyfluorescein. The kinetics of transfer of the dye, analyzed by flow cytofluorimetry with a Fluorescence Activated Cell Sorter (FACS IV), indicate an efficient delivery to the nucleoplasm. The results reflect a liposome-nuclear membrane interaction which may contribute to the processes which underlie our previously described morphological and functional changes in isolated nuclei treated with phospholipids.

Animals↗
PubMed1983

Lomest psychiatric case register: the statistical context required for planning.

Descriptive statistics derived from a psychiatric case register are presented. They may be useful for a more rational planning of new services, and provide a preliminary evaluation of the effects of the recent Act (1978) which has abolished large mental hospitals in Italy. Each component of the 1-year prevalence rates has been examined closely, and the results have indicated three main considerations: abolishing the large mental hospital does not abolish the long-stay patients still living in it, and these people will remain a heavy load on the mental health care system for a long time; the new Act has halved admission rates, but the decline may be a positive result if in-care and out-care are sufficiently integrated; treated out-patients tend to increase year by year, and they seem more and more to be "young men and middle-aged women" suffering from minor psychiatric disorders. Finally, a closer collaboration between planners and evaluators is suggested.

Adolescent↗
PubMed1983

Enzyme activities and metabolites along the kynurenine pathway in mice with Harding-Passey melanoma.

Tryptophan metabolism has been studied in mice with Harding-Passey melanoma and in controls, after a load of 1.0 g/kg b.w. of L-tryptophan by determining ten urinary metabolites of the kynurenine pathway and some enzyme activities involved in the degradation of this aminoacid. Kynurenine was the only tryptophan derivative excreted in significantly higher quantities in mice with melanoma with respect to the controls. This result is in agreement with a significantly higher activity of hepatic tryptophan pyrrolase in mice with melanoma. Liver kynureninase and liver and kidney kynurenine aminotransferase activities were similar in the two groups of mice. These findings point to a possible role of tryptophan in the biogenesis of melanins in pathological conditions such as in melanoma.

Animals↗
PubMed1982

Metabolism and serum levels of tryptophan in senile cataract patients.

In order to clarify the role of tryptophan in the patogenesis of senile cataract, we have studied the serum total and free levels of tryptophan in cataract patients as compared with age and sex-matched controls, and the urinary excretion of 10 metabolites after oral load of the amino acid. This excretion increases in the cataract group both as total per cent and as kynurenine. No difference has been found in the free and total serum tryptophan between normal subjects and cataract patients. A possible role of the kynurenines in the pathogenesis of senile cataract is suggested.

Age Factors↗
PubMed1982

Effects of chloramphenicol and thiamphenicol on the outcome of Chlamydia psittaci infection in chick embryo.

The effects of chloramphenicol (CAP) and thiamphenicol (TAP) on the outcome of Chlamydia psittaci infection in chick embryos were compared. CAP administered along with Chlamydia reduced embryo mortality rates but showed no appreciable effects when its injection was delayed. On the contrary, TAP caused a high rate of embryo survival in both experimental situations. Statistical analysis of the results showed that differences in the survival rates following CAP and TAP administration are significant. Metabolic pathways in chick embryos of the antibiotics assayed differed remarkably in that CAP undergoes a quicker inactivation, which could even justify the better activity showed by TAP.

Animals↗
PubMed1982

Alterations of the tryptophan--nicotinic acid metabolism in vitiligo.

Tryptophan metabolism "via kynurenine" is altered in vitiligo: after a load of the amino acid the urinary excretion of 3-hydroxykynurenine and 3-hydroxyanthranilic acid is decreased, whereas that of xanthurenic acid and its 8-methyl ether is increased. The excretory values of the metabolites suggest a deficiency of the activity of kynurenine hydroxylase and kynunerinase, the enzymes involved in the metabolism of 3-hydroxykynurenine and 3-hydroxyanthranilic acid. The reduced excretion of 3-hydroxykynurenine, a tryptophan metabolite involved in melanin biosynthesis, may indicate a smaller utilization of tryptophan in the biogenesis of the melanins.

3-Hydroxyanthranilic Acid↗
PubMed1981

[Tryptophan metabolism in patients with vitiligo].

Our previous research showed that tryptophan is an important precursor in the biogenesis of melanins. Therefore, with the purpose of observing whether a relationship exists between tryptophan metabolism and diseases characterized by an altered process of skin pigmentation in man, we studied the metabolism of this aminoacid along the kynurenine pathway in 29 vitiliginous patients (11 males and 18 females) and in 21 control subjects (11 males and 10 females) by determining 10 urinary metabolites after an oral loading of 50 mg/kg body weight L-tryptophan. The mean total excretion of the metabolites in patients resulted similar to that of the controls. However, considering the individual metabolites one can observe a decreased excretion of 3-hydroxykynurenine, o-aminohippuric acid and 3-hydroxyanthranilic acid and an increased excretion of xanthurenic acid and of its 8-methyl ether in the group of vitiliginous patients in respect to the controls. These results seem to indicate a decreased formation of nicotinic acid from tryptophan. Moreover, in relation to the fact that 3-hydroxykynurenine could be the metabolite through which tryptophan is involved in melanin biosynthesis, this study supports the hypothesis of a connection of tryptophan metabolism with the lack of pigmentation in vitiligo.

3-Hydroxyanthranilic Acid↗
PubMed1981

Effect of blue light on the urinary excretion of tryptophan metabolites in adult heterozygous and homozygous Gunn rats.

Tryptophan metabolism along the kynurenine pathway has been studied in male and female heterozygous and homozygous adult Gunn rats after load of amino acid before and after exposure to blue light. The percentage of tryptophan metabolites in each group of rats was slightly higher in females than in males. Before irradiation the excretion of metabolites was larger in male and female heterozygous groups than the corresponding groups of the homozygotes. After irradiation only the groups of male and female heterozygous Gunn rats showed a decrease in the total excretion of the metabolites. Therefore blue light exposure dose not seem to influence the metabolism of tryptophan in homozygous Gunn rats.

Animals↗
PubMed1981

Enzyme activities of tryptophan metabolism in heterozygous and homozygous Gunn rats before and after blue light exposure.

The effect of light exposure in the enzyme activities, involved in the tryptophan metabolism along the kynurenine pathway, has been studied in male and female adult hetero-and homozygous Gunn rats. Light exposure did not seem to influence these enzyme activities. The groups of non-icteric heterozygotes however showed a higher activity of liver tryptophan pyrrolase than in the groups of icteric homozygotes. Kynureninase activity was similar in all the groups of rats, whereas liver kynurenine aminotransferase activity appeared slightly higher in the groups of male rats with respect to female rats, but no difference existed before and after irradiation. In addition the male heterozygotes showed a higher kynurenine aminotransferase activity in kidneys than the other groups of rats.

Animals↗
PubMed1981

[Case contribution on intraoperative cholangiography].

An assessment is made of the systematic application of intraoperative cholangiography in the light of a consecutive series gathered over a period of four years. The importance of employing this technique as a routine measure is clearly demonstrated by the results. If properly performed, it greatly reduces unnecessary choledochotomy, diminishes the incidence of overlooked calculi, and leads to the detection of papillo-oddian diseases.

Ampulla of Vater↗
PubMed1981

Effect of psoralen-induced photodermatitis on tryptophan metabolism in rats.

Tryptophan metabolism 'via kynurenine' has been studied in rats before and after induction of experimental light-conditioned dermatitis with psoralen. Tryptophan load in animals during the acute phase of dermatitis (one day after induction) causes a markedly increased urinary excretion of total metabolites in comparison with that obtained before dermatitis. During this phase of the skin disease tryptophan pyrrolase activity is significantly increased and kynureninase activity significantly decreased in liver in respect to the control animals. Kynurenine aminotransferase activity shows no significant variations in both liver and kidneys. After 6 days of dermatitis, when the skin damage is in repair, both the excretory values of the urinary metabolites after L-tryptophan load and the enzymic activities are similar to those before dermatitis.

Animals↗