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Biomedical subjects

T Fazio

Publications and source records attributed to T Fazio.

At least 19 recordsLinked to original sources
PubMed1995

Childhood IQ measurements in infants with transient congenital hypothyroidism.

OBJECTIVE: In view of the fact that, during the first period of life, thyroid hormones are critical for brain development, we investigated whether even transient congenital hypothyroidism could affect the long-term intellectual development of affected infants. DESIGN: A case-control study of intellectual development, auxometric parameters and thyroid function performed in late infancy in children with documented transient congenital hypothyroidism or hyperthyrotrophinaemia at birth. PATIENTS: Nine children born in an endemic goitre area who had short-term transient congenital hypothyroidism or hyperthyrotrophinaemia after birth (TCH) were studied and compared to nine matched children born in the same area at the same time but having normal thyroid function at birth (N). MEASUREMENTS: Global, verbal and performance IQs were evaluated on the Wechsler scale. Height, bone age, total and free thyroid hormones, thyroid volume, thyroglobulin, basal and TRH stimulated TSH were also measured. RESULTS: Height and bone age were similar in the two groups. Thyroid function tests were also similar in the two groups except for basal and TRH stimulated serum TSH and serum Tg which were higher in the TCH than in the control group. Global, verbal and performance IQs were systematically lower in the TCH than in the N group. (78.3 +/- 11.1 vs 90.9 +/- 14.2, P < 0.05; 84.4 +/- 15.4 vs 96.2 +/- 14.8, P NS; 75.0 +/- 8.5 vs 89.2 +/- 12.5, P < 0.01 respectively). CONCLUSION: Infants born and living in an academic goitre area, who had biochemical signs of thyroid hypo-function at birth, had a lower intelligence quotient at the age of 7-8 years than matched controls living in the same environmental conditions but with normal thyroid function at birth. The present findings strongly suggest that abnormalities in thyroid function at birth, even when transient, can adversely affect long-term intellectual development.

Case-Control Studies↗
PubMed1989

HPLC analysis of N-nitrosamino acids and N-nitrosodipeptides N-terminal in proline.

An attempt has been made to develop conditions for the analysis of some N-nitrosamino acids and N-nitrosodipeptides N-thermal in proline by means of high performance liquid chromatography with thermal energy detector (HPLC-TEA). Two HPLC columns have been tested; cyano and amine chemically bonded columns. Although both of them give positive results baseline separation all of the compounds investigated takes place only on the amine column. On the cyano column two of the compounds remains unresolved and two other are not completely separated. Increasing the temperature of the HPLC columns to 90 degrees C and 100 degrees C for the cyano and amine columns respectively dramatically increase their efficiency due to the syn and anti isomers merging.

Amino Acids↗
PubMed1985

Reduction in levels of volatile N-nitrosamines in rubber nipples for babies' bottles.

Levels of volatile N-nitrosamines were determined in 189 samples of rubber nipples for babies' bottles. Domestic (US-manufactured) and imported rubber nipples for consumer and hospital use were analysed to determine compliance with the US Food and Drug Administration's action level of 60 ppb (b = 10(9] for total volatile N-nitrosamines. Only one sample was found to be in violation of the action level; it contained a total of 137 ppb N-nitrosamines.

Bottle Feeding↗
PubMed1984

Nonvolatile N-nitrosamine investigations: methods for the determination of N-nitrosoamino acids and preliminary results of the development of a method for the determination of N-nitrosodipeptides N-terminal in proline.

The development of a rapid method for the determination of N-nitrosoamino acids is reported. Preliminary recoveries of N-nitrosoamino acids in ham fortified with 20 micrograms/kg generally ranged from 70 to 100%. The synthesis and instrumental characterization of four N-nitrosodipeptides N-terminal in proline from nitrite in aqueous acid solution are reported. Electron ionization-mass spectroscopy and infra-red spectroscopy strongly support the conclusion that only the amine nitrogen, and not the amide nitrogen at the peptide bond, is nitrosated. High-performance liquid chromatographic conditions are described for the separation of the synthesized N-nitrosodipeptides.

Amino Acids↗
PubMed1983

Determination of styrene migration from food-contact polymers into margarine, using azeotropic distillation and headspace gas chromatography.

Migration studies were conducted to determine the quantity of styrene that migrates from polymers into fatty foods, specifically margarine. Azeotropic distillation was used to isolate styrene from the margarine. Headspace gas chromatography with a Chromosorb 104 column and a flame ionization detector was used for quantitation. The quantitation limit for the method was about 25 ppb (wt/wt) styrene in margarine. On the average, greater than 90% of the styrene was recovered. Several commercial margarines were examined. The method and results of the migration studies are presented. There was no detectable migration of styrene into margarine.

Chromatography, Gas↗
PubMed1983

Reverse phase high pressure liquid chromatography and fluorescence detection of ethoxyquin in milk.

A high pressure liquid chromatographic (HPLC) method has been developed for the determination of ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethyl-quinoline) in milk. Milk solids are precipitated by adding acetonitrile, and the water-acetonitrile supernate is washed with hexane to remove fat. Addition of sodium chloride causes the water-acetonitrile solution to separate into an aqueous phase and an acetonitrile phase, thus separating ethoxyquin from most water-soluble impurities. A large volume of water is then added to the acetonitrile layer and ethoxyquin is partitioned into hexane, which is removed at reduced pressure. The residue is dissolved in the mobile phase and analyzed on a 4.6 mm id X 250 mm Ultrasphere ODS column using fluorescence detection (excitation 230 nm; 418 nm cutoff filter). Water-acetonitrile with a diethylamine-acetic acid buffer is the mobile phase. Recoveries from samples fortified at 1, 5, and 10 ppb averaged 78% with a coefficient of variation of 5.0%. Low levels (less than 1 ppb) of apparent ethoxyquin were found in commercial milk samples that were analyzed by using the method.

Animals↗
PubMed1983

Survey of baby bottle rubber nipples for volatile N-nitrosamines.

A local market survey of 27 baby bottle rubber nipples for volatile N-nitrosamines was conducted. N-Nitrosodimethylamine, N-nitrosodiethylamine, N-nitrosodibutylamine, and N-nitrosopiperidine were found at levels up to 387 ppb. All 4 nitrosamines migrated from the rubber nipples into water, milk, and infant formula when sterilized together in a manner typical of that used in the home. The source of the nitrosamines is the chemical accelerators and stabilizers added to raw rubber during the vulcanization process.

Animals↗
PubMed1982

Estimation of volatile N-nitrosamines in rubber nipples for babies' bottles.

A method is described for the estimation of volatile N-nitrosamines in the rubber nipples of babies' bottles. In a study of rubber nipples from one manufacturer, N-nitrosodimethylamine, N-nitrosodiethylamine and N-nitrosopiperidine were determined by gas chromatography, using a thermal energy analyser, and their presence was confirmed by mass spectrometry with average levels of individual nitrosamines ranging from 22 to 281 ppb. When the nipples were sterilized in a conventional sterilizer together with milk or infant formula the three nitrosamines migrated into the milk or formula. Storing a bottle of milk with a rubber nipple inverted in it for 2 hr at room temperature or overnight in a refrigerator after sterilization resulted in an 8-13% average increase in the nitrosamine levels migrating into the milk. On repeated sterilization of a single nipple, the quantities of nitrosamines migrating into milk from rubber nipples declined steadily, but after seven sterilizations, nitrosamines were still readily detectable in the milk. Nitrosamine levels were higher in rubber nipples after sterilization, indicating the presence of nitrosamine precursors in the nipples. No nitrosamines were found in raw, uncured rubber. Chemical accelerators and stabilizers added during the vulcanization process are the source of the amine precursors in rubber nipples.

Bottle Feeding↗
PubMed1982

Gas chromatographic determination of sorbitol, mannitol, and xylitol in chewing gum and sorbitol in mints.

A method has been developed for determination of sorbitol, mannitol, and xylitol in chewing gum and sorbitol in mints. Chewing gum is partitioned between methylene chloride and water; the mint is simply dissolved in water. The aqueous extract is dried and the residue is derivatized with pyridine-acetic anhydride to form the corresponding peracetates. The derivatives are quantitated by gas chromatography using a 9 ft x 2 mm column packed with 10% Silar 10C on Chromosorb W/AW. Average recoveries of these sugar alcohols ranged from 96 to 102%.

Candy↗
PubMed1982

Volatile N-nitrosamines in direct flame dried processed foods.

The presence of N-nitrosodimethylamine (NDMA) in malt and malt beverages has been linked to the direct flame drying of malt. Similar drying procedures are used in the preparation of a variety of foods, such as non-fat dry milk, soy proteins and dried cheeses. A survey of some of these processed foods for volatile N-nitrosamines has shown that low levels of NDMA are present, along with N-nitrosomorpholine in one sample of soy protein isolate. This paper describes the procedures used for the analysis of a variety of processed dried foods for volatile nitrosamines and reports the results obtained.

Animals↗
PubMed1982

Gas-liquid chromatographic-thermal energy analyzer determination of N-nitrosodimethylamine in beer: collaborative study.

The GLC/TEA method for N-nitrosodimethylamine (NDMA) in beer was studied collaboratively by 13 laboratories from 7 countries. Collaborators were asked to analyze a total of 10 randomly labeled samples of beer consisting of the following duplicates: a naturally contaminated commercial beer; a beer extremely low (ca 0.1 ppb) in NDMA; and the low NDMA beer spiked with 0.5, 1.9, and 5.0 ppb NDMA. The pooled repeatability and reproducibility coefficients of variation (CV) for all samples were 17% and 27%, respectively. However, when data from 2 laboratories (outliers) were omitted, the corresponding CV values improved considerably (11% and 15%, respectively). Variance analysis showed the presence of a significant laboratory-sample interaction when all data were used for analysis, but this interaction disappeared when data from the 2 outlying laboratories were excluded. The pooled percent recovery of the overall method (omitting outliers) was 101.4 +/- 3.5. All the laboratories detected NDMA in the low NDMA beer. The method was adopted official first action.

Beer↗
PubMed1982

Evaluation of three methods for recovery of sulfamethazine metabolites from swine tissue.

Recent investigations have clearly established the presence of desaminosulfamethazine (I), N4-acetylsulfamethazine (II), and N4-D-glucosyl sulfamethazine (III) in the tissues of swine which have been dosed with sulfamethazine (V). N4(1-Deoxy-D-glucuronyl) sulfamethazine (IV) has frequently been found in the urine and feces of animals. These metabolites have generally not been investigated in current sulfamethazine methods; therefore, it is not clear to what extent they might be measured by these procedures. Metabolites I, II, III, and IV were synthesized and characterized by several chemical and physical measurements. These metabolites and their parent, V, were added to swine tissue and recoveries were measured by a gas-liquid chromatographic (GLC), a colorimetric, and a gas chromatographic/mass spectrometric method with electron ionization-selected ion monitoring (GC/MS EI-SIM). With modifications of the gas chromatographic parameters, the GLC method can quantitate compounds, I, II, and V simultaneously. If a hydrolysis step is added, all 3 methods can quantitate compound II as V and, in addition, the GC/MS EI-SIM and colorimetric methods can quantitate III as V. In none of these methods do metabolites I, II, III, or IV interfere in the determination of V.

Animals↗
PubMed1982

High performance liquid chromatography with fluorescence and ultraviolet detection of polynuclear aromatic hydrocarbons in barley malt.

A simple, rapid method has been developed for the separation and determination of polynuclear aromatic hydrocarbons (PAHs) in barley malt. An ultrasonic-cyclohexane extraction method was used to separate the PAHs from ground barley malt. The cyclohexane extracts were purified by chromatography through a water-deactivated silica gel-alumina column. The eluate from the column was concentrated and purified further by partitioning between dimethyl sulfoxide (DMSO) and cyclohexane. The DMSO extract was diluted with water and the PAHs were extracted back into cyclohexane. The cyclohexane extract was washed with water, dried through sodium sulfate, and evaporated, and the resulting residue was dissolved in 80% aqueous acetonitrile-methanol (1 + 1) and subjected to reverse phase high performance liquid chromatography. Thirty barley malt samples were analyzed using this procedure. Peaks having the same retention time as the carcinogen benzo(a)pyrene were isolated from 18 of the samples, and were equivalent to trace levels ranging from less than 0.1 to 0.2 ppb. Average recoveries of 11 PAHs, including benzo(a)pyrene, benzo(b)fluoranthene, indeno(1,2,3-cd)pyrene, and benz(a)anthracene, added to 25 g samples at 2.5 and 5 ppb, ranged from 78 to 97%, with a mean relative standard deviation of 6.6%.

Chromatography, High Pressure Liquid↗