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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The urinary excretion and serum levels of thyroxine (T4), triiodothyronine (T3) and 3,3',5'-triiodothyronine (reverse T3) was estimated in a longitudinal study of human newborns. The maternal and cord blood was also studied. Neonatal renal function was evaluated using endogenous creatinine clearance. In cord blood serum T3 was found to be lower than in maternal blood, but reverse T3 highly elevated. During the first 5 days of life serum T4 and T3 increased with maximum at 48 and 24 h in contrast to reverse T3 which remained high and then declined rapidly after 4 days. Creatinine clearance during the first 3 days of life increased from 5.3 to 21.9 ml/min/1.73 m2. In the same period the urinary T4 excretion increased from 79 to 281 ng/24 h, urinary T3 excretion from 16 to 44 ng/24 h and urinary reverse T3 from 4 to 15 ng/24 h. The renal excretion of thyroid hormones, corrected for body surface, was decreased compared to adult controls, corresponding to an immature renal function. The lack of ability to excrete thyroid hormones involved primary T3 and reverse T3 suggesting particular immaturity of tubular secretion of these hormones during the neonatal period.
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PMID:Urinary excretion of thyroxine, triiodothyronine, 3,3',5'-triiodothyronine (reverse T3) and renal function in human newborns. 69 80

In a prospective study we estimated common renal parameters in 48 full term normal neonates, of which 15 were also tested at 6 months and 12 months of age. The mean levels of serum creatinine, were high at birth (0.73 mg/dl) but normal for age at 6 and 12 months; uric acid followed a similar trend. The blood pH and bicarbonate were low at birth (7.28 and 20.36 mEq/L, respectively) reached normal adult values by 12 months; chloride levels were high at birth (110 +/- 5 mEq/L) and normal at 6 months. The plasma renin activity was higher than normal all throughout the first year (27.1, 416.8, 64.8 ng/ml/hr by RIA). Plasma aldosterone values were high at birth (1387.5 pg/ml) and reached normal level (301.6) at 12 months. Renal length and volume as assessed by ultrasonography compared well with American standards. Urinary constituents were variable due to breast feeding up to 6 months and varied diet during the weaning period. This study shows that mild metabolic acidosis and hyperchloremia due to immaturity of renal acidification mechanism and high renin and aldosterone levels due to partial nonresponsiveness of distal tubules are normal variables in babies from birth to 6 months. The levels of serum creatinine and uric acid are high at birth and in assessing renal functions this should be borne in mind.
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PMID:Renal parameters during infancy. 129 93

Thirteen biochemical parameters and five enzymatic activities were determined on sera of 63 normal human fetuses sampled by direct puncture under ultrasound guidance, between the 20th and the 26th wk of gestation, and on their mothers. They were referred to us for various prenatal diagnoses but were well and confirmed healthy at birth. Some parameters were found to be very similar in both groups, mainly creatinine, calcium, creatine kinase, aspartate aminotransferase, and gamma-glutamyl transferase. Some values were significantly higher in the fetuses, such as total bilirubin, direct bilirubin, phosphorus, lactic dehydrogenase and alkaline phosphatase activities, and alpha-fetoprotein. Urea, uric acid, glucose, triglycerides, cholesterol, total protein, and albumin levels were found to be lower in fetuses. These data indicate a slower metabolism in fetuses compared to their mothers, a lower level of energy requirement, and a relative liver immaturity. These normal values of fetal biochemistry will improve our knowledge of physiology and help to determine the specific values of a test in fetal pathology.
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PMID:Blood chemistry of normal human fetuses at midtrimester of pregnancy. 243 76

Serum immunoreactive parathyroid hormone (iPTH), ionized calcium, the urinary cyclic AMP/creatinine ratio (cAMP/Cr) and some indices of bone turnover (alkaline phosphatase (AP), serum osteocalcin, and the urinary total hydroxyproline/creatinine ratio (OH-P/Cr)) were measured in 26 preterm infants during the first 4 weeks of life. Despite of stimulated parathyroid gland activity cAMP/Cr, AP, osteocalcin and OH-P/Cr were low during the first week. Thereafter iPTH decreased, whereas cAMP/Cr, and the indices of bone turnover increased, reaching high-normal values (in comparison to full-term infants) during the second and third week of life. Serum iPTH was negatively correlated to cAMP/Cr in the first week (r = -0.61, p less than 0.01), whereas the relationship became positive during the second (r = 0.47, p less than 0.05) and third (r = 0.54, p less than 0.05) week of life indicating maturation of the renal response to PTH. The study supports the concept that in premature infants a transient pseudohypoparathyroid-like state is present during the first week of life reflecting an immaturity of renal and possibly bone response to PTH. This may be an etiological factor in hypocalcemia of prematurity.
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PMID:Evidence for transient peripheral resistance to parathyroid hormone in premature infants. 303 25

Forty-two bone marrow aspirates and biopsies during follow-up examinations from patients with multiple myeloma were reviewed to determine whether the results correlate with the clinical state of the patient at the time of examination. The percentage of plasma cells on biopsy and aspiration, cytological immaturity, patterns of plasma cell infiltration, and the presence or absence of multiple lymphoid nodules and marked fibrosis were cross-tabulated with clinical parameters (hemoglobin levels, osteolytic lesions, and renal function). Hemoglobin levels less than 10 g/dl were more frequent in those with greater than 70% plasma cells on either aspiration or biopsy (P less than 0.05). A nodular histological pattern on biopsy, however, had a higher correlation with hemoglobin levels less than 10 g/dl, and serum creatinine levels greater than 2 mg/dl, than did plasma cell number. The presence of lymphoid nodules correlated with less lytic bone lesions. The degree of fibrosis and plasma cell immaturity did not correlate with any of the clinical parameters. Our findings suggest that reports on bone biopsies should include in addition to the number of plasma cells, the pattern of plasma cell infiltration and the presence or absence of multiple lymphoid nodules.
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PMID:Bone marrow biopsy in multiple myeloma: a clinical pathological study. 340 26

A prospective renal ultrasound study of 134 newborns (49 prematures weighing less than 2500 g and 85 more mature babies) was undertaken to investigate factors associated with increased renal cortical echogenicity (RCE). Increased RCE was seen in 39 (29 per cent) babies. It was significantly related to body weight, age, medical status, blood urea nitrogen, and serum creatinine. In view of the interdependence of these factors, however, multivariate analysis was performed, which revealed that age was the most important factor associated with increased echogenicity (r = -0.46), and the other factors had only small independent effects, increasing the multiple r to 0.56. The authors conclude that an infant's immaturity is the most important determinant of increased RCE.
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PMID:Factors associated with renal parenchymal echogenicity in the newborn. 353 33

The optical density of amniotic fluid at 650 nm (OD650) has been proposed as a rapid means of assessing fetal pulmonary maturity. Two hundred eighty-two amniotic fluid samples were analyzed for OD650, L/S ratio and creatinine concentration, and those values were related to the infants' pulmonary outcome. Among those infants delivered within 72 hours of amniocentesis, pulmonary maturity was predicted accurately in 98.3% by the OD650, 97.7% by the L/S ratio and 97.6% by the creatinine concentration. All three tests were unreliable in predicting pulmonary complications when the tests revealed pulmonary immaturity. OD650 values were found to vary inversely with centrifugation speed, reaffirming the need for standardized processing techniques to achieve reliable results. Marked discrepancies occurred between the diagnoses given by three neonatologists asked to retrospectively evaluate the likely etiology of pulmonary problems in nine infants suspected of having respiratory distress syndrome.
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PMID:Comparison of amniotic fluid optical density, L/S ratio and creatinine concentration in predicting fetal pulmonary maturity. 402 Jul 87

Seven tension pneumothoraces developed in six very low birthweight infants receiving assisted ventilation for hyaline membrane disease. Mean values for blood pressure and creatinine clearance (Ccr) tended to increase following pneumothorax decompression, although neither increase was statistically significant. Urine volume, osmolar clearance and urine sodium excretion all increased significantly in the 8 h following diagnosis and decompression of pneumothoraces. However, when expressed as a percentage of Ccr, none of these variables changed significantly. Mean sodium balance changed from positive to negative despite a significant increase in urine aldosterone excretion. It is suggested that the increases in osmolar clearance and sodium excretion were consequences of the increase in Ccr following pneumothorax decompression. Developmental immaturity in the renal tubular response to aldosterone might also have contributed to development of negative sodium balance.
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PMID:Diuresis and natriuresis following acute pneumothorax in very low birthweight infants. 409 68

Twelve-hour urinary excretion of 4-hydroxy-3-methoxymandelic acid (VMA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) was studied in 20 premature infants, 8 without apnea and 12 with apnea. All infants were studied at 1-3 days of postnatal age (before apnea). Nonapneic infants were restudied at 10-15 days of postnatal age. Apneic infants were also restudied 24 h after apnea. Apnea was not associated with decreased urinary excretion of VMA and MHPG. Only HVA, when expressed as microgram/kg body weight, was significantly lower after the onset of apnea. This difference disappeared when HVA was expressed as microgram/mg creatinine. We suggest that apnea of prematurity may not be related to the immaturity of catecholamine pathways.
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PMID:Study of neurotransmitters in premature infants with or without apnea of prematurity. 613 Aug 40

A case is reported in which serial L/S ratios, determined from fluid samples collected vaginally after premature rupture of the membranes, led to a grossly erroneous conclusion of fetal pulmonary immaturity. The fetus was in breech presentation, and in retrospect several 'amniotic fluid' samples consisted largely of fetal urine. Determination of the creatinine concentration of suspect samples should permit distinction to be made between mixed amniotic fluid and fluid containing a disproportionately large amount of fetal urine when the possibility of this error exists.
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PMID:The L/S ratio in vaginally collected amniotic fluid: a misleading result in a breech presentation. 650 Jan 50


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