Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate the aspecific activity of inflammatory effector cells (mononuclear and polymorphonuclear leukocytes) of newborn babies, a comparative study was performed of chemotactic and random filter motility, phagocytic activity, and bactericidal capacity of these cells, of the electron microscopic counterparts of these activities, the serum factors influencing motility and of the content and ratio of cyclic nucleotides present in the cells of subjects of different ages. It was found that chemotaxis of the mononuclear and polymorphonuclear leukocytes is a gradually maturing function; its deficiency observed during the neonatal period is not caused by a depressed excitability by chemical agents, by the presence of inactivators of chemotactic factors or of chemotaxis inhibitors. It is the low serum levels of total complement, C 3, IgG, IgM and properdin that explain the reduced chemotactic mobility. In addition to these factors reduced leukocyte flexibility, condition and activity of the flexibility, condition and activity of the microtubular and microfilamentary system depending on calcium ion and cyclic nucleotide concentrations, and an eventual immaturity or exhaustion of certain intracellular enzymes also play a part. In respect to orientation towards chemical stimuli, the leukocytes of the newborn largely differ from those of children or adults. Similarly, a difference in uptake and elimination of bacteria and in ultrastructural changes accompanying these processes can be demonstrated between newborn and adult cells. The aspecific cellular functions, the reduction of which plays an important part in the weak resistance of the newborn, also depend on certain properties of the infective agents.
 ...
PMID:Activity and characteristics of inflammatory effector cells in newborns. 647 70

The etiology and prevention of rickets in prematures infants are still controversial: insufficient storage or intake in minerals and/or vitamin D, immature vitamin D metabolism, necessitating early vitamin supplementation, for some associated with calcium and phosphate supplementation. The authors report a case of rickets which could be related to an immaturity of the tubular mechanisms of phosphate reabsorption, with a favourable outcome following an increase in calcium and phosphate intake.
 ...
PMID:[Hypophosphatemic rickets in premature infants independent of vitamin D]. 650 85

Animal experimental studies conducted at the turn of the century resulted in the use of magnesium sulphate as an anticonvulsant in humans. In U.S. clinics, parenteral administration of magnesium sulphate became a routine procedure in the treatment of eclampsia and pre-eclampsia. This treatment has proved very effective in treating convulsions in pregnancy provided an adequate dosage was given amounting to up to 60 g daily. Mother and infant mortality were largely eliminated. Numerous clinical studies showed a negligible side effect rate. Side effects in the foetus: These are due to penetration of magnesium into the foetal blood circulation. Reports on an inhibition of cardiac rate fluctuation and changes in calcium levels have been contradictory, and hence not generally accepted. It is claimed that the parathormone level may drop slightly. Isolated reports on foetal magnesium intoxications associated with depression of breathing, slackness and hyporeflexia often prompt the conclusion that this disease pattern had been due to immaturity and asphyxia. Generally, foetal magnesium blood levels do not correlate well with signs of magnesium intoxication. Urine excretion is greatly slowed down in foetal immaturity. Side effects in the mother: Short-term relaxing action on the uterus has been described frequently. High dosages have been successfully used in arresting labour if there is a tendency to premature birth. Increase in uterine blood flow was seen after administration of magnesium sulphate in animal experiments. Magnesium is said to reduce blood coagulation by influencing fibrinolysis and thrombocyte resistance. However, a somewhat enhanced loss of blood during birth is said to be more likely due to relaxation of the uterus than to a disturbance of blood coagulation. Rapid intravenous injection causes short-term flushing, nausea and vomiting. Short-acting drops in blood pressure are possible. The cardiac output is said to increase at the conventional dosage level whereas the peripheral resistance drops due to vasodilation. Increases and decreases in heart rate have been reported, but in most cases no changes were seen. Changes in ventricular action time occur with toxic doses only, which can lead to cardiac arrest in the diastole. Other toxic signs are hyporeflexia, depressed breathing and CNS depressions which may result in coma. Hyporeflexia always occurs before the other toxic signs appear, so that it can be used as a clinical control criterion. Calcium gluconate, given via the IV route, is a good and rapid-acting antidote.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:[Use of magnesium sulfate as an anticonvulsant in severe pregnancy toxemia and eclampsia]. 655 75

Six lamb fetuses at 63-101 days gestation had thyroidectomy (Thx) and were investigated at term for weights, radiologic study, serum thyroxine (T4), and thyroid-stimulating hormone concentrations (TSH), electron-microscopic lung examination, acid base, blood flow, EEG, and brain metabolism. Compared to age-matched controls, body weight was significantly reduced (P less than .025). Brain and lung weights were reduced but not significantly. Brain weight as a percent of body weight was significantly increased in Thx fetuses (Thx = 1.85% +/- 0.18; control = 1.41% +/- 0.08; P less than .025). Hemoglobin was reduced (P less than .025), as was O2 content (P less than .005) and cerebral blood flow (P less than .05). Fetal T4 was low (Thx = 4.1 +/- 1.7 microgram %, control = 9.4 +/- 1.3 microgram %); (P less than .05). Fetal Thx cortisol, calcium, phosphate, glucose, lactate, pH, pO2, pCO2, O2 saturation, heart rate, and blood pressure remained unchanged. Thx-fetal brain O2 consumption and glucose consumption, as well as lactate production, were unchanged. EEG showed no consistent pattern of change regarding maturity, but did show immaturity with the two lowest T4 levels. Bone microradiographs showed growth and maturity retardation, specifically delayed epiphyseal closure, endochrondral ossification, and lack of secondary ossification centers in Thx fetuses. Electron-microscopic examination of lung showed Thx fetuses had fewer lamellar bodies in type II cells, fewer type II cells, and more glycogen granules. Thx causes fetal reduction of T4 and anemia, delays lung maturation and bone growth and maturation.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Midtrimester thyroidectomy in the ovine fetus. 664 76

Calcium and sodium permeability of erythrocytes from patients with untransfused alpha- or beta- thalassemia major has been studied and compared to mature erythrocytes or control cells with comparable reticulocytosis. Isotopic Na(+) influx was increased a mean fourfold greater than normals and threefold greater than reticulocyte rich control. Passive net leak of Na(+) into thalassemic cells incubated with ouabain was also increased corresponding to their greater (22)Na(+) influx. Erythrocyte Na(+) and K(+) concentrations and cell water content per unit volume of cells were normal. Quantitation of active cation pumps in the cell membrane by the technique of [(3)H]ouabain binding showed a 2.6- to 9.9-fold increase above normal. Inward Ca(2+) movement was studied in cells with absent Ca(2+) pumping produced by depletion of either ATP or Mg(2+)-ions. Calcium uptake by ATP depleted thalassemic cells was increased 12-fold above normals and 3.6-fold above reticulocyte-rich controls. The Ca(2+) uptake by Mg(2+)-depleted thalassemic cells was also increased above normal confirming that erythrocyte Ca(2+) permeability is increased in this disease. Osmotic fragility measurements show that the surface area to volume ratio of thalassemic erythrocytes was increased by 15 to 25% above mature erythrocytes. The increased passive cation permeability of thalassemic erythrocytes cannot be explained by either reticulocytosis or an increased surface area to volume ratio of these cells. Moreover, erythrocyte Na(+) and Ca(2+) influxes in congenital dyserythropoietic anemia (CDA type 2) were increased 2- and 14-fold, respectively, above normal. The increased cation fluxes and cation pump numbers in thalassemic and congenital dyserythropoietic anemia erythrocytes are consistent with the hypothesis of membrane immaturity arising from rapid marrow transit times, a concept previously advanced to explain the persistence of i-antigen on these cells.
 ...
PMID:Increased erythrocyte cation permeability in thalassemia and conditions of marrow stress. 720 77

The myocardium of the neonate has incomplete sympathetic innervation and decreased sensitivity to cardiotonic agents. It is not known whether the neonatal myocardium exhibits the tendency to develop reserpine-induced supersensitivity to cardiotonic agents. Using isolated ventricular muscles from 1-week-old and adult rabbits, concentration-response relationships of inotropic tension to isoproterenol, ouabain, norepinephrine and calcium were determined with and without reserpine pretreatment. Ventricular muscles from the newborn animals exhibited the same degree of reserpine-induced supersensitivity to isoproterenol and ouabain as that seen in the adult animals. Although the newborn demonstrated reserpine-induced supersensitivity to calcium, the adult did not. Neither age group demonstrated reserpine-induced supersensitivity to norepinephrine. These findings indicate that newborn animals are capable of producing reserpine-induced supersensitivity, despite the immaturity of their cardiac sympathetic innervation, contractile machinery and beta-adrenergic mechanisms. These results also indicate the non-selective nature of reserpine-induced supersensitivity.
 ...
PMID:Comparison of reserpine-induced supersensitivity of newborn and adult rabbit ventricular muscles to cardiotonic agents. 726 43

Recently described techniques for separating myosin isoenzymes have been adapted for analysis of myosins from diseased and developing human skeletal muscle. The method is highly suitable for analysis of human myosins because only 2 - 3 mg of muscle are required for routine analyses. Human embryonic/foetal myosins are electrophoretically distinct from mature skeletal myosins, and are not normally detected beyond the first month of post-natal life, except in premature infants. They have a high alkaline calcium-activated ATPase activity. This would account for the histochemical classification of foetal fibres as "Type II", although physiological differences between adult fast-twitch muscle and foetal muscle are well recognized. Foetal myosins are also synthesized in human skeletal muscle under certain pathological circumstances. Their presence in Duchenne dystrophy probably reflects the associated marked muscle regeneration, with immaturity of some muscle cells. The large amounts of foetal myosin present in many cases of infantile spinal muscular atrophy is evidence that innervation is necessary for the normal cessation of foetal myosin synthesis.
 ...
PMID:Embryonic and foetal myosins in human skeletal muscle. The presence of foetal myosins in duchenne muscular dystrophy and infantile spinal muscular atrophy. 731 Apr 40

Age-related changes in the response rabbit papillary muscles to isoproterenol and calcium were studied. Newborn rabbit papillary muscles were not only less sensitive to the inotropic effect of isoproterenol and calcium, but also produced significantly less maximal inotropic tension to these agents in comparison to the adult. The decreased response of newborn papillary to isoproterenol appears to be due to a combination of (a) decreased ability of papillary muscle to respond to calcium and (b) immaturity of isoproterenol-sensitive contractile mechanism. Differences in myocardial norepinephrine content do not appear to play an important role in the age-related difference in the response to isoproterenol and calcium.
 ...
PMID:Comparative inotropic response of newborn and adult rabbit papillary muscles to isoproterenol and calcium. 743 67

To extend our studies about phenotypical and functional alterations of G-CSF-induced neutrophils we have evaluated their light-scatter profile, mobilization of intracellular calcium ([Ca2+]i) and membrane depolarization after stimulation. A significant increase in the forward scatter signals could be demonstrated in such neutrophils from patients with neutropenias of various origin and from healthy test subjects. This increase began 4 h and returned to normal 96 h after G-CSF injection in the latter group. We found an impairment of [Ca2+]i mobilization in neutrophils from patients with glycogen storage disease type IB after stimulation of these cells with fMLP. It was even more pronounced than in severe congenital neutropenia (SCN). However, [Ca2+]i fluxes were normal when ionomycin was used. Neutrophils from patients with cyclic neutropenia (cyNP) and chemotherapy-induced neutropenia (chNP) mobilized [Ca2+]i similar to those from healthy donors. Furthermore, we found a decreased percentage of neutrophils depolarizing after stimulation with fMLP and PMA in patients with SCN, whereas membrane depolarization was normal in patients with chNP and cyNP. All the alterations found here are suggested to be caused by a partial immaturity of the neutrophils, although in vivo activation and a direct effect of G-CSF on myeloid precursors might be involved.
 ...
PMID:Changes in light-scatter profile, membrane depolarization and calcium mobilization of neutrophils induced by G-CSF in vivo. 752 31

Renal handling of magnesium (Mg) has not been comprehensively studied in the newborn period due to the difficulty, until recently, of measuring the diffusible fraction of plasma Mg (UfMg). In the present study this methodology was used to assess Mg homeostasis in 84 newborn infants of different postconceptional age (26-42 weeks), weight (720-4,830 g) and postnatal age (1-72 days). Very premature infants (postconceptional age less than 35 weeks) had significantly higher values of plasma Mg than mature newborn infants. Plasma Mg related inversely to postconceptional age, weight, plasma total protein and plasma calcium, and directly to plasma potassium. Stepwise multiple regression analysis revealed that postconceptional age was the unique factor contributing to variations in plasma Mg. Plasma values of UfMg were the same in preterm as in term infants but, when expressed as a fraction of total plasma Mg (UfMg/Mg), they were significantly lower in very preterm infants. Fractional excretion of Mg and the ratio of urine Mg to urine creatinine did not vary as a function of postconceptional age. These results indicate that plasma UfMg is kept constant at different gestational ages despite variations in total plasma Mg; furthermore, no functional immaturity is present for renal tubular reabsorption of Mg, even in very low birth weight infants.
 ...
PMID:Magnesium homeostasis in premature and full-term neonates. 757 1


<< Previous 1 2 3 4 5 6 7 8 Next >>