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

The composition of the spinal fluid was determined in 54 healthy premature infants in the first week of life. The infants were divided into three groups according to their gestational age; the results in each group, submitted to variance analysis, indicated similar values. The results in these premature infants were then compared with those in 79 normal full-term infants. The spinal fluid of the pre-term children showed higher bilirubin concentrations, more hemoglobin and higher levels of protein, indicating a greater permeability and immaturity of the blood-brain barrier. There were more erythrocytes in the premature infants, while the number of leukocytes and their differential count were similar in both groups; the only difference was the number of eosinophils, which were absent in the premature infants.
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PMID:[Composition of the cerebrospinal fluid in the premature newborn infant]. 91 56

Strict clinical management of a diabetic mother who is pregnant reduces the risk of neonatal complications. It also reduces the frequency of fetal macrosomia. Diabetic mothers have a heavier placenta than mothers who are not diabetic. Light microscopic placental changes associated with diabetes include villous immaturity and dysmaturity. We have examined the placentas of 27 diabetic mothers whose maternal hemoglobin A1c (HbA1C) levels were measured throughout pregnancy. None of these placentas had a trimmed weight in excess of 600 grams. Eighteen of 27 specimens had immature villi. Four had dysmature villi. Three placentas had fibromuscular sclerosis within the villi. Five had cholangiosis and there was one cholangioma. Villous immaturity was present in 16 of 18 mothers whose HbA1C was more than 5.6% of the total hemoglobin. We found villous immaturity in 2 of 5, within 5.1-5.5% HbA1C. There was no villous immaturity in four cases whose HbA1C was less than 5.0% total hemoglobin. Our findings indicate that maternal hyperglycemia during pregnancy is associated with placental immaturity and dysmaturity.
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PMID:[Correlation of placental villous immaturity and dysmaturity with clinical control of maternal diabetes]. 185 19

Erythrocytosis and microcytosis have been described in strains of genetically hypertensive rats and in essentially hypertensive humans. Published discussion of these phenomena has centered around their relationship to observed alterations in ionic transport and the pathogenesis of hypertension. In presenting data for another strain of spontaneously hypertensive rats in which these findings are exhibited, we note that erythroid cell size decreases concurrently with the increase in cell numbers so that the hematocrit and the mean corpuscular hemoglobin concentration remain constant. Data from the literature support the hypothesis that erythroid cell size is inversely proportional to cell count in a large number of species. Erythrocytosis, as it develops in the neonatal rat, is a consequence of the marked immaturity of this species at birth. Erythrocytosis in the spontaneously hypertensive rat is not due to a difference in the affinity of its hemoglobin for oxygen or to significant tissue anorexia. Microcytosis in the spontaneously hypertensive rat is the consequence of a continuation of the linear volume decrease with age of its erythroid cells seen in the normotensive animals and may be accounted for by the production of smaller cells with concomitant regulation of individual cell volume.
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PMID:Inverse changes in erythroid cell volume and number regulate the hematocrit in newborn genetically hypertensive rats. 194 11

Although the domestic pig is rapidly becoming an animal of choice in certain areas of biomedical research requiring a large animal model, effective utilization of the species is often encumbered by a lack of reference values for common functional variables. To address this problem, normal data for over 100 physiologic or related variables were collected from conscious chronically instrumented animals that were maintained under near basal conditions. Included were measurements of body composition, fluid volumes, blood physical and biochemical characteristics, blood gas and acid-base status, plasma hormone levels, energy metabolism, renal function, hemodynamics and pulmonary function. Most porcine values were similar to those collected under comparable conditions from humans. Compared to adult man, however, pigs had higher values for extracellular space, plasma volume, arterial pH, plasma bicarbonate, cardiac output, arterial pressure, expired ventilation, heat production, and core temperature, and lower values for red cell volume, hemoglobin level, plasma osmotic and oncotic pressure, arterial O2 content, renal blood flow and glomerular filtration rate. Many of these deviations were due to immaturity. Nevertheless, we have found pigs to be an excellent large animal model for a variety of functional studies.
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PMID:Normal physiological values for conscious pigs used in biomedical research. 216 86

Data from 12,481 delivered newborns show that the duration of gestation has an significant influence on the actual blood-gases and the ph-value. Under comparable clinical conditions in the newborns (Apgar score after one minute) one can observe a steadily increasing metabolic acidosis with increasing maturity of the neonate. Mature and vigorous infants (Apgar score 9 and 10) have, according to our data, an actual pH-value below 7,100 in 0.5 to 0.7% and a pH-value below 7,200 in 13 to 16%. An exaggerated fear of acidosis does not seem justified in these vigorous neonates. In small, vaginally delivered premature newborns, pH-values below 7,200 with an incidence of approx. 28% occur not only more often, but are also combined with severe clinical depression (Apgar score 1-4). Therefore pH-values below 7,200 should be avoided especially in extremely immature neonates. In summary, one observes with increasing immaturity a sort of dissociation of the clinical and biochemical status of the newborn. This observation confirms the efficiency of pH-measurement in umbilical blood. Therefore the definition of the risk of acidosis (number [%] of infants with pH-values below 7,100 [umbilical artery]) should never be analysed alone, but always in combination with the gestational age. Similarly, this statement seems to be valid also for acid-base-values like base-excess, pCO2 and the percentage of oxygen saturation of hemoglobin.
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PMID:[Is there a gestational age dependent risk of acidosis?]. 250 Nov 43

5-Azacytidine (azaC) has previously been shown to raise Hb F levels in the repeatedly phlebotomized baboon (PCV: around 20%). The administration of tetrahydrouridine (THU), an inhibitor of the enzymatic conversion of azaC to 5-azauridine, made it possible to reduce the amount of azaC and also of 2-deoxy-5-azacytidine (d-azaC) by more than 90% and still achieve maximal Hb F elevations. However, the granulocytopenia, usually occurring after 5-azaC, was not altered by the lowering of the dosages in the presence of THU. Thus, the granulocytopenia is not due to 5-azauridine or other catabolic products resulting from deamination. It is also unlikely that it is caused by a direct influence of azaC on RNA since d-azaC also causes granulocytopenia. The persistence of reticulocytosis throughout the treatment with azaC or d-azaC makes it appear likely that the observed increase in Hb F levels to more than 60% of total hemoglobin is not due to a cytotoxic effect on erythropoiesis resulting in a shift of cell populations toward greater immaturity, but to a direct influence of the drug on the regulation of gamma globin chain production.
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PMID:Tetrahydrouridine, cytidine analogues, and hemoglobin F. 257 48

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

In this review, we have considered interrelationships between blood flow and oxygen requirements of the body during fetal and neonatal development. During fetal life, blood is oxygenated in the placenta and returns to the fetus through the umbilical vein. The ductus venosus serves as a bypass of umbilical venous blood from the hepatic microcirculation. Preferential streaming of blood in the inferior vena cava facilitates delivery of well-oxygenated ductus venosus blood to the brain and heart. During fetal stress of hypoxia or umbilical cord compression, flow through the liver and ductus venosus is modified to facilitate oxygen delivery to the fetal body and local organ vascular responses, and to maintain blood flow and oxygen delivery to vital organs, such as the brain, heart, and adrenal gland. During fetal life, immaturity of the fetal myocardium accounts for limited ability for cardiac output to be augmented when ventricular filling pressure is increased above the resting level; yet immediately after birth, cardiac output increases dramatically. Experimental evidence points to an important role of prenatal thyroid hormone in maturation of the myocardium for postnatal requirements. In association with the increase in oxygen requirements after birth, cardiac output increases, but because resting requirements for blood flow are high, there is a limited ability for cardiac output to be increased further. With postnatal development, cardiac output requirements in relation to body weight decrease, partly in parallel with reduced oxygen requirements related to body weight, but also as a result of rightward shift of the oxygen dissociation curve as fetal hemoglobin is replaced by adult hemoglobin. Understanding the circulatory and metabolic changes that occur in the perinatal period and the mechanisms of response to stress is important in management of the newborn infant with cardiorespiratory distress.
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PMID:Perinatal oxygen delivery and cardiac function. 390 77

In the course of ontogeny, the homing site for the hematopoietic stem cells (HSC) moves with certain predictability from the yolk sac to the liver/spleen and then to the marrow. The pattern of this migration has thus far been established mostly on a morphologic basis. To delineate further the course of this migration and to gain insight into its possible mechanism, we used in utero transplantation of allogeneic or xenogeneic HSC in preimmune sheep fetuses. Sex chromosome, type of hemoglobin, and species-specific surface markers were used to follow the path of transplanted cells in the fetus. Before the development of the bone marrow, transplanted HSC (liver- or marrow-derived) homed exclusively to the liver/spleen. With the development of marrow, around day 60 of gestation (term, 145 days), homing occurred also in the nascent marrow and by day 80 transplanted cells homed exclusively to the marrow. This suggests that there may be a hierarchy in homing sites, with those of the marrow having higher affinity than those of liver/spleen. Interestingly, despite a change in homing that was followed by the expansion of the marrow compartment of HSC (ie, HSC proliferation), these cells did not participate actively in blood cell formation during most of the prenatal period. Liver remained the major hematopoietic organ throughout the gestation. It was only during the perinatal period that this organ assumed the function of hematopoiesis from the liver. This lack of expression of HSC in fetal marrow can possibly be attributable to the immaturity of marrow stroma required for differentiation and maturation of progenitors and the orderly egress of mature cells into the blood stream. The availability of this model allows us to begin studies in the molecular mechanism of stem cell homing in vivo during ontogeny.
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PMID:Liver-derived fetal hematopoietic stem cells selectively and preferentially home to the fetal bone marrow. 809 67

Surfactant has led to a significant reduction in neonatal mortality for premature infants with lung immaturity and respiratory distress. However, surfactant therapy has been shown to be effective in the treatment of a number of other neonatal respiratory disorders and the evidence for surfactant use in such circumstances is presented. Meconium aspiration is characterised by severe atelectasis, the influx of neutrophils, edema, and hyaline membranes, with decreased levels of SP-A and SP-B and the large aggregate fraction of lung surfactant, and altered surfactant surface morphology. Meconium contains cholesterol, free fatty acids and bilirubin all of which can interfere with surfactant function in a dose-dependent fashion. Providing larger amounts of surfactant can overcome some of this inhibition. Animal models of meconium aspiration treated with surfactant have improved histology, lung mechanics and gas exchange. Studies in human infants with meconium aspiration have found elevated concentrations of total protein, albumin, and membrane-derived phospholipid in lung lavage fluid, and haemorrhagic pulmonary edema. Clinical studies in such neonates have reported improved gas exchange and clinical outcomes following surfactant treatment. More recently surfactant lavage has been shown to be a potentially efficacious therapy for such infants. The inflammatory exudate containing plasma proteins and cytokines which accompanies neonatal pneumonia may inactivate surfactant. Surfactant treatment given to animals following the tracheal instillation of group B Streptococcal resulted in significantly less bacterial growth and improved lung function. Small clinical experiences have demonstrated the benefit of surfactant to infants with pneumonia/sepsis. Pulmonary haemorrhage, which some consider a complication of surfactant therapy, has also been effectively managed using surfactant instillation. The hemoglobin and red blood cell lipids may act to inhibit natural surfactant and treatment with surfactant has been shown to improve outcome for infants with pulmonary haemorrhage. Animal models of congenital diaphragmatic hernia (CDH) have hypoplastic lungs with evidence of decreased lamellar bodies in their type II pneumocytes and resultant surfactant deficiency, and respond to surfactant replacement with improved gas exchange and lung mechanics. The lungs of human infants with CDH contain less phospholipids and phosphatidylcholine per milligram of DNA than control infants. Case reports have reported a benefit of surfactant for infants with CDH. In the near-term infants with severe respiratory distress, surfactant is one of the therapies along with inhaled nitric oxide and high frequency ventilations, that have resulted in improved outcomes. Surfactant treatment may be of significant benefit in newborn infants with respiratory compromise secondary to a number of insults, and further prospective evidence of its efficacy in such disorders is needed.
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PMID:Surfactant use for neonatal lung injury: beyond respiratory distress syndrome. 1498 Feb 86


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