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Biomedical subjects

N Uga

Publications and source records attributed to N Uga.

7 recordsLinked to original sources
PubMed1992

Prevention of perinatal transmission of hepatitis B virus carrier state.

By means of passive and active immunization with hepatitis B immunoglobulin and hepatitis B vaccine, 396 of 407 babies born to hepatitis B antigen-positive carrier mothers, were protected from establishing the hepatitis B virus (HBV) carrier state during a follow-up period of 12 months or longer. Four infants developed the HBV carrier state before the completion of the immunoprophylaxis schedule, and another seven developed the state after the completion of the schedule. Seroconversion of anti-HBc was observed in 26.8% of the successfully protected infants. In Japan a nationwide program to prevent the vertical transmission of HBV with these procedures was established in 1986, and so liver diseases due to HBV are expected to be eliminated in the near future.

Carrier State↗
PubMed1991

Influence of perinatal factors and sampling methods on TSH and thyroid hormone levels in cord blood.

To evaluate the effect of perinatal factors and sampling methods on thyroid stimulating hormone (TSH) and thyroid hormone levels in cord blood, serum TSH, free thyroxine (FT4) and free triiodothyronine (FT3) concentrations were measured in 124 healthy term neonates. Eighty-eight infants were born in normal vaginal deliveries, 25 were delivered by vacuum extractor and 11 by Cesarean section. There was no significant difference among the three infant groups in the mean TSH levels. Birth weight, the infant's sex, duration of labor and uterotonic agents had no effect on cord serum TSH and free thyroid hormone levels in the neonates born by normal vaginal delivery. To assess the adequacy of specimen collection, mixed cord blood samples, obtained by a direct application of cord on a filter paper, and venous blood withdrawn with a plastic syringe were collected in another 200 infants. There was a significant linear correlation in the TSH concentration in mixed cord blood and cord venous serum from the same individuals, while a poor correlation was found in T4 values from two specimens. Our results suggest that the TSH value in cord blood is less influenced by perinatal factors, including the sampling method, and the mixed cord blood collected by this technique might be a feasible alternative specimen for a TSH screening program with cord blood which is useful in countries where neonatal blood is not available.

Blood Specimen Collection↗
PubMed1990

Maturation of feedback control of thyrotropin in premature infants.

Serum thyrotropin (TSH), free T4 and free T3 concentrations were measured longitudinally in 26 preterm infants for 14 weeks after birth, using highly sensitive immunoradiometric assays. Serum TSH values on days 4-5 were positively correlated with gestational age and birth weight. In the premature infants of 25 weeks mean gestation, the mean TSH concentrations increased from a very low value of 0.84 microU/ml at 5 days to a peak value of 6.1 microU/ml by 5 weeks of age, then slightly decreased and remained stable. Serum free T4 and free T3 concentrations increased in parallel and free T3 level reached the range of term infants by 6 weeks. Serum free T4/TSH and free T3/TSH ratios began to increase at the 6th week of age. The results suggest that: (i) the thyroid hormone feedback control of pituitary TSH release in the extremely premature infants begins to mature after 6 weeks of postnatal age, (ii) the maturation pattern of the hypothalamic-pituitary-thyroid system in premature infants is similar to that of the intrauterine fetus.

Birth Weight↗
PubMed1989

[Statistical study of factors related to occurrence and progression of retinopathy in extremely premature infants: especially clinical changes in PaCO2 and pH].

Out of 39 premature infants admitted to the NICU in Toho University Hospital from January 1983 to December 1985 and surviving for 2 months after birth, 22 extremely premature infants who were closely matched in terms of gestational age and body weight at birth were divided into 4 groups (operated group, non-operated A group, non-operated B group and broncho-pulmonary dysplasia (BPD) group) to assess the effect of respiratory management on retinopathy of prematurity (ROP). ROP occurred at a high frequency in extremely premature infants weighing less than 1,000 g. In most of the infants who underwent operation (cryocauterization), PaCO2 values were low for 1 month after birth, whereas pH tended to rise. In the non-operated B group, PaCO2 was almost normal, and pH tended toward acidosis. BPD, which causes severe respiratory disturbance, was observed in 4 cases, 3 of whom showed a rise in PaCO2 within 1 month after birth, but mild ROP. Thus, it was considered that PaCO2 and pH exacerbated ROP.

Carbon Dioxide↗
PubMed1987

[Study on serum TSH and its response to TRH measured by a high sensitive immunoradiometric assay during and after pregnancy].

With a new highly sensitive immunoradiometric assay (IRMA), serum thyrotropin (TSH) concentrations were determined in 213 healthy pregnant women. Serum free thyroxine (FT4) and human chorionic gonadotropin (HCG) levels were also measured in the same individuals. The mean serum TSH value in the 1st trimester was 0.8 microU/ml and significantly lower than those of the other three periods and non-pregnant women. Seventeen of 77 (22.1%) and 2 of 128 (1.6%) subjects in the 1st and 3rd trimester, respectively, had an undetectable serum TSH value (less than 0.1 microU/ml) with normal or slightly elevated serum FT4 levels and these pregnant women had no clinical signs or symptoms of thyrotoxicosis. Significant positive correlations were found between serum FT4 and HCG in the 1st and 3rd trimester. In 13 subjects whose serum basal TSH values had been less than 0.1 microU/ml, the thyrotropin-releasing hormone (TRH) stimulation test was performed. Two of 4 subjects in the 1st trimester and one of 8 subjects in the 2nd trimester did not respond to TRH and their serum TSH values before TRH administration were less than 0.1 microU/ml. Although the exact mechanism of blunted TSH response to TRH is not clear, the feedback suppression of serum TSH by slightly elevated serum FT4 concentrations may occur early in pregnancy. However, in the 3rd trimester serum FT4 values fell below the reference range without an elevation of serum TSH. Other factors regulating the secretion of TSH during pregnancy can be postulated.

Female↗