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Biomedical subjects

R Bellisario

Publications and source records attributed to R Bellisario.

14 recordsLinked to original sources
PubMed2001

Simultaneous measurement of antibodies to three HIV-1 antigens in newborn dried blood-spot specimens using a multiplexed microsphere-based immunoassay.

We developed a fluorescent immunoassay to simultaneously measure antibodies to three HIV-1 antigens from newborn dried blood-spot specimens. The multiplexed assay uses fluorescent microspheres and a flow analyzer. The procedure is sensitive, precise and accurate, and can be expanded to simultaneously measure additional multiple analytes from a single specimen.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Multivariate discrimination for phenylketonuria (PKU) and non-PKU hyperphenylalaninemia after analysis of newborns' dried blood-spot specimens for six amino acids by ion-exchange chromatography.

Ion-exchange HPLC was developed for testing dried blood-spot specimens from newborns. The method is suitable for quantitative confirmatory testing of abnormal specimens detected in the New York State Newborn Screening Program. Positive specimens were initially identified among all New York State newborns with semiquantitative bacterial inhibition assays (BIA) for aminoacidopathies, including phenylketonuria (PKU) and non-PKU hyperphenylalaninemia (HP), maple syrup urine disease, and homocystinuria. A selection of 1346 specimens from routine BIA screening, including 131 newborns with PKU or persistent HP, were tested by HPLC. Of 179 BIA results that were falsely positive, 98 (55%) were also falsely positive by HPLC in which the Phe/Tyr ratio was the discriminator and the threshold was set to attain 100% sensitivity. Investigation of three multivariate discriminatory methods revealed that linear discriminant analysis excluded all but 35 (20%) of the BIA false-positives.

Amino Acids↗
PubMed1997

Identification and characterization of two groups of congenital hypothyroid infants: implications for newborn screening.

A retrospective analysis of 400 newborns diagnosed with congenital primary hypothyroidism between 1983 and 1987 was conducted. Two distinct groups of cases were identified and characterized based on their newborn screening TSH value. The two groups are separated at a TSH concentration of 50 mU/l of serum by a normal probability plot. This finding is in agreement with the 1993 recommendation from the American Academy of Pediatrics that infants with a low T4 level and a TSH concentration greater than 40 mU/l be considered to have primary hypothyroidism until proven otherwise. The group of infants with TSH less than 50 mU/l have a higher proportion of males and low birthweight infants. For this group, T4 increases with increasing TSH. We find that screening TSH, T4, and birthweight are predictive of follow-up serum TSH level for the cases with TSH > 50 mU/l but not for cases with TSH < 50 mU/l. An optimal rule for selecting screening cutoff levels is presented based on only T4, TSH and their interaction. Adjustments for sex, birthweight or age at which sample was taken did not aid in distinguishing cases from controls for newborns whose age of sample is 2 days or greater.

Congenital Hypothyroidism↗
PubMed1984

Abnormalities of thyroid function in infants with Down syndrome.

We describe 12 of 1130 infants with Down syndrome in whom various degrees of thyroid dysfunction were detected by neonatal screening. These aberrations were confirmed subsequently in 11 patients. In eight of 11 children, persistent primary hypothyroidism, was diagnosed, whereas in the remaining three patients transient thyroid abnormalities were noted. The twelfth patient died and could not be retested. We found an incidence of persistent primary congenital hypothyroidism in infants with Down syndrome of 1:141, or about 28 times more than in the general population. The cause of thyroid aberrations in these infants remains unclear; none of the studied patients had agenesis or ectopia of the thyroid gland. On initial screening most infants with Down syndrome had only mild biochemical abnormalities, with gradual decompensation occurring thereafter. Infants with Down syndrome are therefore at high risk for congenital hypothyroidism and should have careful follow-up to prevent further deterioration of their mental development or growth.

Child, Preschool↗
PubMed1983

Measurement of serum alpha-fetoprotein in early infancy: utilization of dried blood specimens.

Serum alpha-fetoprotein (AFP) concentrations were measured in dried blood spots and the biologic half-life of AFP was determined during the first month after parturition. AFP blood levels, in babies at all birthweight groups during the first wk, were partitioned according to birthweight and sex. A synthetic surge of serum AFP at postnatal day 3 was observed in babies of the low birthweight category (less than 6 lb 8 oz), whereas a concomitant surge could not be demonstrated in babies of medium, (6 lb 8 oz to 8 lb 8 oz), and high birthweight, (greater than 8 lb 8 oz), categories. All babies weighing less than 6 lb 8 oz, regardless of prematurity likewise displayed the synthetic surge. The sex of the infant appeared to have no influence on AFP serum concentrations. In a population of infants ranging in age from 1-30 days, the biologic apparent half-life of AFP was calculated as 5.7 days; however, the half-life of AFP was found to differ among the three groups of infants when subdivided by birthweight and was higher (7.7 days) in babies of low birthweight. Our determination of 2 S.D. cutoff values for AFP in the first wk of life should prompt further studies in which the relationship of AFP to newborn disorders should be more fully explored.

Birth Weight↗
PubMed1982

Commercial radioimmunoassay kit for measurement of alpha-fetoprotein adapted for use with dried blood specimens from newborns.

We adapted a commercial RIA kit to measure alpha-fetoprotein (AFP) in 0.785-microliters portions of 60-microliters spots of dried blood from newborns. We evaluated sample elution, temperature and time stability, between- and within-assay variability, sensitivity, and use of liquid vs dried specimens of blood. Also, we present normal AFP concentrations for healthy neonates during the first postnatal week. Our procedure permits measurement of AFP concentrations both in maternal liquid plasma and in spots of dried blood from the infant with the same RIA kit reagents and standards. The sensitivity, precision, stability, and simplicity of this procedure makes more practical the routine measurement of AFP in dried blood specimens from newborns than measurement in liquid plasma or serum. Blood-sample collection by heel stick suffices for this simple, efficient, inexpensive determination of AFP concentration in the newborn.

Blood Chemical Analysis↗
PubMed1975

Human chorionic gonadotropin. V. Tissue specificity of binding and partial characterization of soluble human chorionic gonadotropin-receptor complexes.

An in vivo human chorionic gonadotropin (hCG)-receptor complex was solubilized from the subcellular fraction of ovarian and testicular tissues of rats that had been injected with 125-I-labeled hCG. The soluble hCG-receptor complex was partially characterized by Sepharose 6B chromatography in the presence of the nonionic detergent, Emulphogene, and was shown to have a molecular size of about 65 A. By this method it was also shown that the in vivo uptake of radioactivity by rat gonadal tissues represents 125-I-hCG and not the dissociated subunits or degradation products of the hormone. A soluble hCG-receptor complex isolated in vitro in approximately the same yield from both rat testicular and ovarian homogenates was shown to be the same size. The hCG-receptor appears to be specifically located in gonadal tissue; a corresponding hCG-receptor complex was not obtained from liver or kidney that incorporated significant levels of 125-I-hCG administered in vivo. Furthermore, a desialyzed hCG-receptor complex was obtained from rat testis but not liver; desialyzed hCG, like other desialyzed glycoproteins, is nonspecifically bound by rat liver homogenates. The binding of hCG and luteinizing hormone (LH) by rat testis receptor exhibits a high degree of specificity. Other glycoprotein hormones without LH activity, such as follicle-stimulating hormone and thyroid-stimulating hormone, and glycoproteins such as fetuin or alpha1-acid glycoprotein do not bind to the hCG/LH receptors. Desialyzed hCG was 2 times more effective in competing for binding to rat testis receptors than "native" hCG, indicating that caution must be exercised when the radioligand receptor assay is utilized to assay hCG preparations varying in sialic acid content.

Animals↗