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

To test the hypothesis that intarpartum acidosis has a role in the etiology of hyaline membrane disease (HMD), blood was collected from the umbilical artery (UA) at birth from 110 premature infants and analyzed for hydrogen ion concentration ([H+]), PCO2, standard bicarbonate, and lactic acid. The infants were followed until a definite diagnosis was made of HMD (33 infants), type II respiratory distress syndrome (16 infants) or the absence of respiratory distress (61 infants). In general, infants with HMD were more premature and had lower Apgar scores than nondistressed infants; however, there were no significant differences between the two groups in any acid-base measurement. Only in those patients of 32 to 37 weeks' gestational age was it possible to detect a significant increase in UA [H+] in infants with HMD compared to those without respiratory distress. There was evidence that the reduced Apgar score of infants with HMD may be due to immaturity and abnormal pulmonary function secondary to lung disease. It is concluded that acidosis at birth is not a factor in the development of HMD except possibly in more mature infants.
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PMID:The role of acidosis at birth in the development of hyaline membrane disease. 95 Nov 32

Histories of deliveries and development records of 44 newborns with penumopathies who had died on the first days of life in the presence of phenomena of the syndrome of respiratory disorder were analysed and the newborns' lungs were morphologically investigated. The investigation made it possible to single out the following forms of pneumopathy in newborns: edematous-hemorrhagic, hyaline, atelectatic, aspirated, and mixed. In the majority of cases the syndrome of respiratory disorder was a sequela of hypoxia of the intrauterine origin which continued during the first hours and days of life after birth. Such "primary asphyxia" may lead to the development of pneumopathy in a neonate. On the other hand, "secondary asphyxia" in many cases represent sequelae of penumopathy destructural and functional immaturity of the pulmonary tissue, hypoxia, a higher permeability of vessels of the microcirculatory bed, spasm of small pulmonary arteris contributed considerably to the development of penumopathies.
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PMID:[Morphology of pneumopathies and their role in the development of asphyxia neonatorum]. 98 37

Surfactant is now available for general clinical use in infants with RDS. While surfactant is effective, it does not prevent lung disease in many preterm infants because of other aspects of lung immaturity. In experimental models, corticosteroids alter the fetal lung by improving compliances, increasing lung volumes, decreasing pulmonary edema, and altering surfactant-compliance dose response curves. These effects are independent of changes in surfactant pools but augment the responses of the lungs to surfactant treatment. Optimal outcomes for the preterm require the combined use of fetal maturation strategies and postnatal surfactant.
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PMID:Surfactant in the perinatal period. 139 80

The immaturity of the lung of the very prematurely delivered newborn appears to make it hypersusceptible to injury by those very therapeutic measures that the infant requires shortly after birth--mechanical ventilation and hyperoxia. There is good experimental evidence to relate the immature lung's susceptibility to early hyperoxia-induced lung damage to deficient antioxidant defensive systems. Less than fully adequate nutritional support of these tiny newborns can have extremely detrimental effects on their lungs' ability to resist and repair on-going injury and to continue developing normally. Promising experimental means of possible protection from hyperoxic lung damage and progression to chronic lung disease (bronchopulmonary dysplasia) are reviewed.
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PMID:Antioxidants, nutrition, and bronchopulmonary dysplasia. 152 71

The premature baboon delivered by hysterotomy at 140 +/- 2 days (75%) gestation develops hyaline membrane disease (HMD) and left-to-right (L-R) shunting through the patent ductus arteriosus (PDA). To characterize hemodynamic changes that follow premature delivery, we measured systemic and organ blood flow, oxygen transport, and systemic vascular resistance over the first 96 h of life. We compared these measurements with those from more mature animals of the same species. Radiolabeled microspheres were used to measure organ blood flow (in ml.min-1.g-1) at 3 (n = 18), 23 (n = 17), and 96 h (n = 4) in the premature animals, and at 13 +/- 4 mo in the older animals (n = 5). Premature animals demonstrated over the first 96 h of life significant hemodynamic changes that included decreased systemic vascular resistance (P less than 0.001), increased systemic (P less than 0.05), intestinal (P less than 0.05), and hepatic blood flow (P less than 0.05), as well as resolution of L-R PDA shunting. These 96-h values were similar to those of the more mature infant baboons. Blood flow and oxygen transport to the kidneys and cerebrum did not significantly increase over the first 96 h in premature baboons and were significantly less than those of 13-mo-old animals (P less than 0.01, both). We speculate that low renal and cerebral blood flow in the 140-day premature baboon are manifestations of multisystem immaturity and, as such, may represent persistent physiological disturbances that are distinct from the severity of underlying lung disease in HMD.
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PMID:Circulatory changes following premature delivery in a baboon model of hyaline membrane disease. 192 96

The in-hospital findings for infants of 500-1,500 g birthweight admitted for intensive care over the years 1971-87 were reviewed at four intervals. Survival rate improved substantially. The incidence of chronic lung disease (CLD) in survivors at 28 days of age was unchanged though severity diminished in terms of both mortality and degree of radiographic change. Mean conceptual age for ceasing supplemental oxygen was 32 weeks for those with normal X-rays and 37 weeks for abnormal X-rays regardless of initial degree of immaturity. CLD was diagnosed twice as often when supplemental oxygen beyond 28 days was used as an indicator as against an abnormal X-ray and was hence unreliable for this purpose. Since candidates for CLD are a heterogeneous group care is needed in analysis or selection of material in forming conclusions which concern etiology or management.
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PMID:A 15-year survey of chronic lung disease of prematurity. 264 47

A preterm rat model has been developed for studies of acute and chronic neonatal lung disease. Premature delivery 24 h before the normal time of delivery is associated with immature pulmonary phospholipid and antioxidant enzyme profiles. The premature lung is more fragile and ruptures at a lower lung vol (172 +/- 8 microL) than the full-term fetal lung (259 +/- 14 microL). Only 7% of premature lungs will float in liquid, after inflation to 85% of the rupture vol, compared with 87% of term fetal lungs. This lung immaturity was reflected in a survival rate of only 6% by 36 h after delivery if the preterm pups were placed in air, which increased to 47% when they were placed in greater than 95% oxygen. Though greater than 95% oxygen enhanced survival of preterm pups during the 1st wk of life, these survivors had a 50% mortality during the 2nd wk of exposure to greater than 95% oxygen. The preterm pup will tolerate intraperitoneal injection of antioxidant enzymes entrapped in liposomes and has a better retention of these liposomes in the lung compared with the term pup. We conclude that the preterm rat is a suitable model for studies of acute and chronic neonatal lung disease.
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PMID:The preterm rat: a model for studies of acute and chronic neonatal lung disease. 271 69

Amino acid analysis of human fetal lung elastin was undertaken in 49 instances of live-born neonates, ranging from 380 g to full term, and in 3 abortuses of 12-14 wk gestation. The data suggest that formation of the cross-linking agents, desmosine and isodesmosine, occurs early, between 14 and 22 wk. The ratio of neutral to charged amino acids remains low until the 36th wk when it attains adult levels. The composition of elastin was independent of sex and duration of survival. In three neonatal pulmonary diseases (respiratory distress syndrome, atelectasis, and hemorrhage) ratios were significantly lower than those found in nondiseased lungs. This may be a reflection of immaturity or may be a predisposing factor in neonatal lung disease. The latter hypothesis is attractive and receives indirect support from the association of a more polar elastin with other diseases, including adult emphysema and atheromatous aortic change.Our finding of relatively high polarity in elastin from human fetal lung is consistent with previous observations in a variety of fetal organs of other species.
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PMID:Lung tissue elastin composition in newborn infants with the respiratory distress syndrome and other diseases. 483 91

Lambs prematurely delivered by cesarean section and term lambs were supported on ventilators and studied over a period of 2 days. Sequential measurements of ventilatory requirements, lung compliance, and arterial pH, pO2, and pCO2 values documented the course of the lung disease. In five premature lambs the pCO2 increased to 77 +/- 5 mm Hg (mean +/- SE) by 40.5 +/- 3.1 hr of age, at which time treatment with 50 mg natural sheep surfactant lipid/kg body weight by tracheal instillation resulted in improvements in pH, pO2, and pCO2 measurements. Radiolabeled palmitic acid was injected systemically after birth to detect the appearance of endogenously synthesized and secreted saturated phosphatidylcholine in sequential airway samples. Radiolabeled saturated phosphatidylcholine specific activity increased in a relatively linear fashion for about 30 hr in lambs treated with natural surfactant, in untreated premature lambs, and in term lambs. The study demonstrates that surfactant therapy can improve the ventilatory status of premature lambs despite many hours of ventilation for pulmonary immaturity. The overall kinetics of secretion of saturated phosphatidylcholine is similar in lambs with and without pulmonary immaturity.
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PMID:Saturated phosphatidylcholine secretion and the effect of natural surfactant on premature and term lambs ventilated for 2 days. 655 78

We studied Ureaplasma urealyticum colonization in 93 intubated infants (gestational ages 23-40 weeks) in our neonatal intensive care unit by obtaining cultures from endotracheal aspirate and nasopharynx during their first week of life. Eighteen infants had positive cultures, giving a colonization rate of 19%. No infant more than 30 weeks' gestation had a positive culture. The infants with positive cultures had a significantly lower gestational age and birth weight (p < 0.009 and p < 0.005), with a colonization rate of 33% in infants less than 1000 g. Among the infants with positive cultures, 10 of 17 developed chronic lung disease in contrast with 21 of 72 infants with negative cultures. The development of chronic lung disease and duration of oxygen requirement was strongly associated with immaturity but only weakly with Ureaplasma urealyticum.
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PMID:Neonatal Ureaplasma urealyticum colonization and chronic lung disease. 781 88


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