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Biomedical subjects

M Biasiolo

Publications and source records attributed to M Biasiolo.

At least 19 recordsLinked to original sources
PubMed2001

Enzyme activities involved in tryptophan metabolism along the kynurenine pathway in rabbits.

The following enzyme activities of the tryptophan-nicotinic acid pathway were studied in male New Zealand rabbits: liver tryptophan 2,3-dioxygenase, intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase, kynureninase, kynurenine-oxoglutarate transaminase, 3-hydroxyanthranilate 3,4-dioxygenase, and aminocarboxymuconate-semialdehyde decarboxylase. Intestine superoxide dismutase and serum tryptophan were also determined. Liver tryptophan 2,3-dioxygenase exists only as holoenzyme, but intestine indole 2,3-dioxygenase is very active and can be considered the key enzyme which determines how much tryptophan enters the kynurenine pathway also under physiological conditions. The elevated activity of indole 2,3-dioxygenase in the rabbit intestine could be related to the low activity of superoxide dismutase found in intestine. Kynurenine 3-monooxygenase appeared more active than kynurenine-oxoglutarate transaminase and kynureninase, suggesting that perhaps a major portion of kynurenine available from tryptophan may be metabolized to give 3-hydroxyanthranilic acid, the precursor of nicotinic acid. In fact, 3-hydroxyanthranilate 3,4-dioxygenase is much more active than the other previous enzymes of the kynurenine pathway. In the rabbit liver 3-hydroxyanthranilate 3,4-dioxygenase and aminocarboxymuconate-semialdehyde decarboxylase show similar activities, but in the kidney 3-hydroxyanthranilate 3,4-dioxygenase activity is almost double. These data suggest that in rabbit tryptophan is mainly metabolized along the kynurenine pathway. Therefore, the rabbit can also be a suitable model for studying tryptophan metabolism in pathological conditions.

3-Hydroxyanthranilate 3,4-Dioxygenase↗
PubMed2000

Tryptophan in human hair: correlation with pigmentation.

The distribution of tryptophan content in human hair of various colours was evaluated, in order to study the accumulation of this amino acid, precursor of serotonin, melatonin and niacin, in hair and the influence on hair pigmentation. Pigmentation is an important factor in determining drug incorporation into hair. Results from 1211 samples of hair from healthy subjects (577 men and 634 women) show that tryptophan levels are significantly higher in males (37.83 +/- 3.45 microg/g dry hair) than in females (26.62 +/- 2.40 microg/g hair). Besides sex, age also influences the distribution of tryptophan in human hair, the highest levels being found in both sexes in the first few years of life, probably due to the influence of milk, and in aging subjects in the groups of 61-80 and > 80 years. In order to investigate the influence of hair colour, hair samples were subdivided according to colour into blond, dark blond, red, light brown, brown, black, grey and white. The hair contents of tryptophan in both sexes was higher in brown and black hair than in blond hair, but in grey and white hair concentrations were the highest, demonstrating that tryptophan accumulates among hair fibres with age. Grouping subjects by age in relation to hair colour, we observed that at ages 1-5 and 6-12 years, colour did not influence tryptophan contents, but at ages 13-19 and 20-40 years tryptophan content increased significantly from blond to brown at 13-19 years and from blond to black at 20-40 years in both sexes. Therefore, variations in tryptophan levels of human hair appear to be correlated with differences in hair colour in both sexes. Tryptophan also accumulates in hair during keratinization, as shown by the presence of high levels of this amino acid in grey and white hair.

Adolescent↗
PubMed1999

Liver and kidney kynurenine aminotransferase activity in different strains of rats.

Variations in liver and kidney kynurenine aminotransferase (KAT) activity in Pittsburg-Yoshida, Brown-Norway, albino Wistar, Sprague-Dawley, Long Evans and heterozygous Gunn rats were studied. In liver, values of KAT specific activity, expressed as mumoles of kynurenic acid formed per hour per mg of protein, were different in the groups of Brown-Norway and Pittsburg-Yoshida rats versus Long Evans and Sprague-Dawley rats. The activity expressed as mumoles of kynurenic acid per g of fresh liver showed other differences, being significantly higher in Gunn with respect to other strains of rats and lower in Pittsburg-Yoshida and Brown-Norway rats. In addition, KAT activity was significantly lower in Pittsburg-Yoshida than in Brown-Norway rats. In kidney, the specific activity of kynurenine aminotransferase showed significant differences in the values of Sprague-Dawley and Long Evans rats versus the other strains. The activity expressed per g of fresh tissue was significantly higher in Wistar, Sprague-Dawley, Long Evans and Gunn than in Pittsburg-Yoshida and Brown-Norway rats. No significant differences were found in values between hyperlipidemic Pittsburg-Yoshida and their control Brown-Norway rats. These results high-light the importance of considering various rat strains when inbred animal experimental models are used.

Animals↗
PubMed1999

Correlation between tryptophan and hair pigmentation in human hair.

The concentration of tryptophan in human hair of various colours is determined in order to study their correlation with hair pigmentation. The mean levels of this amino acid in hair samples are higher in men than in women. Therefore, sex influences the content of tryptophan in human hair. In addition, age influences the distribution, the highest levels are observed in the 1-5 year age-group and in ageing subjects in the groups up to 61-80 years in both sexes. The hair samples subdivided, according the colour, into blond, dark blond, red, light brown, brown, black, grey, and white demonstrate that in both sexes the concentrations of tryptophan are higher in brown and black hair than in blond hair. However, the tryptophan levels are highest in grey and white hair, showing that tryptophan accumulates among hair fibres with age. Therefore, there is a correlation between tryptophan content and hair pigmentation.

Adolescent↗
PubMed1996

Determination of copper and zinc levels in human hair: influence of sex, age, and hair pigmentation.

The Cu and Zn levels of both 607 men (1-85 y old) and 649 women (1-92 y old) were determined by atomic absorption spectrometry. Sex does not influence Cu (14.89 + or - 0.89 mu g/g and 15.26 + or - 0.79 mu g/g hair for males and females, respectively) and Zn contents (200.97 + or - 9.68 mu g/g for men and 209.81 + or - 9.49 mu g/g hair for women). Age influences Cu and Zn concentrations, but only significantly in females: Cu levels decrease over 60 y of age; whereas Zn levels increase significantly from age groups 2-5 to 20-40 years. Hair color influences Cu concentrations in both males and females. In males, white hair contains less Cu than black hair; in females, white hair's Cu levels are significantly lower than those of dark blond, red, light brown, and brown hair. There are no significant differences in Zn concentrations with respect to different hair colors, in either males or females.

Adolescent↗
PubMed1994

Laser desorption ionization mass spectrometry in the study of natural and synthetic melanins. II--Serotonin melanins.

Various biosynthetic melanins obtained by enzymic oxidation of serotonin with polyphenol oxidase from Psalliota campestris mushroom or potato, and with tyrosinase from Sepia officinalis or from Sigma were studied by means of laser desorption ionization mass spectrometry. Various oligomeric clusters were evidenced, proving that the examined melanins are composed of sets of different oligomers, the production of which strongly depends on the enzyme reaction. While serotonin melanins obtained with polyphenol oxidase from potato showed wide species distribution with molecular weights ranging from 2008 to 13,000 Da, the same melanins obtained from mushroom showed oligomer distributions from 1505 to 9000 Da. Serotonin melanins prepared with tyrosinase from Sepia showed oligomers from 1636 to 18,000 Da. A dopa-melanin obtained with mushroom polyphenol oxidase showed oligomer species from 1709 to 17,874 Da. Comparison of molecular weight distributions of the various oligomer sets in serotonin melanins with those in tyrosine melanins revealed clear differences, which are investigated and discussed.

Agaricus↗
PubMed1990

Fast atom bombardment mass spectrometry in the study of dopamine melanogenesis intermediates.

Fast atom bombardment was applied to the study of the intermediates of the reaction dopamine-tyrosinase after treatment with diazomethane. The identification of trimethoxyindoline, dopamine-o-quinone and dimethoxyindole was easily achieved by this ionization method, together with accurate mass measurements and collision experiments. The structures of these compounds are in agreement with those already hypothesized in studies on melanogenesis.

Dopamine↗
PubMed1989

Serum total and free tryptophan levels in term infants fed cow's milk formula or human milk.

We found no significant differences in mean total and free tryptophan concentrations in sera of healthy, full-term infants fed cow's milk formula and healthy, full-term infants who were breast-fed. Serum tryptophan concentrations were measured 1 h after feeding when the infants were 2 and 6 days of age. In this study cow's milk formula compared favourably with human milk as primary nutrition for full-term infants, despite a two-to-three fold higher level of free tryptophan in human colostrum.

Animals↗
PubMed1989

Free and bound tryptophan in human milk during early lactation.

Total (protein-bound and free) and free tryptophan levels of breast milk were evaluated in 10 mothers of term infants on the 3rd, 4th, 5th, and 30th day of lactation. We found high levels of both total and free tryptophan in the colostrum. This variation in tryptophan content of breast milk may reflect the requirement of the human neonate.

Female↗
PubMed1988

Collisional spectroscopy in structural characterization of melanins. 2--Laser desorption experiments on bio- and synthetic tryptophan melanins.

Melanins are naturally occurring macromolecules whose structural complexity appeared evident from the first researches of Quilico. Their structural characterization remains a difficult problem, mainly due to the physico-chemical properties of such compounds. Melanins are insoluble in organic solvents as well as aqueous solutions and are infusible. Consequently the traditional chemical degradation and physicochemical methods such as ultraviolet, infrared, 1H and 13C nuclear magnetic resonance, ESR (electron spin resonance), XPS (X-rays photoelectron spectroscopy) and X-ray diffraction have led, until now, to limited information on melanin chemical structure.

Chemical Phenomena↗
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↗
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

Gc subtypes determined by ultrathin-layer isoelectric focusing. Distribution in the Veneto population (Italy).

The distribution of Gc phenotypes in the population of Veneto was investigated by ultrathin-layer isoelectric focusing. In our sample (n = 732) the six common phenotypes, Gc 1S, 1F, 1S1F, 2, 2-1S, 2-1F and a further phenotype, GC 1S1C3, were observed and the following frequencies calculated: Gc 1S = 0.560792; GC 1F = 0.159153; Gc2 = 0.277323; Gc 1C3 = 0.002732. Our gene frequencies have been compared with those found in other populations.

Gene Frequency↗
PubMed1984

The detection of A and B antigens on human hair by the absorption-elution technique using LISS and papain-treated test cells.

The absorption-elution technique with low ionic strength solution (LISS) and papain-treated test cells previously used for bloodstains was employed for the detection of ABO antigens on human hair. Antigen identification was always possible, with good intensity of agglutination, even in those cases where classic techniques had given false-negative results. It was possible to obtain positive results with fragments of human hair as small as 0.2 cm.

ABO Blood-Group System↗