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

Monolayers of suckling rat hepatocytes cultured for 24 hours were treated with galactose, I-tyrosine and I-methionine. The purpose was to study the reasons for the clinical improvement of patients with neonatal hepatitis after dietary restriction of these nutrients. Galactose, tyrosine, and methionine was cytotoxic on suckling rat hepatocytes, yet had no effect on adult rat hepatocytes. Furthermore, the pretreatment of suckling rat hepatocytes with dexamethasone ameliorated the cytotoxicity and induced a differentiation of the cells. These results suggested that the cytotoxicity resulted from the immaturity of suckling rat hepatocytes and therefore dietary restriction of galactose, tyrosine and methionine might be a useful treatment for patients with neonatal hepatitis.
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PMID:Cytotoxicity of galactose, tyrosine and methionine in cultured suckling rat hepatocytes: relation to liver immaturity. 260 21

This study examines the effect of a low sulfur amino acid diet (LTD) and a high taurine diet (HTD), compared with a normal diet, on the plasma, urine, muscle, brain and renal cortex levels of taurine in immature and adult rats. Milk taurine from lactating dams reflected the taurine content of the diet, being low in LTD-fed and high in HTD-fed animals. Nursing pups (7, 14 and 21 d old) often had plasma, urine and tissue--renal cortex, heart, skeletal muscle--levels of taurine related to dietary exposure, a situation also found in adult animals. These diets did not influence the urinary excretion of the sulfur-containing alpha-amino acids methionine and cystine but a sulfur aminoaciduria of immaturity was evident. By contrast, the content of taurine in brain was constant regardless of dietary intake of sulfur amino acids. An age-related decline in brain taurine content was found--as noted by others--but this too was influenced by diet. This dual finding of brain taurine constancy despite wide differences in sulfur amino acid intake and changes in the renal handling of taurine as influenced by diet suggest that the renal adaptive response serves to maintain the stability of brain taurine content.
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PMID:Studies on renal adaptation to altered dietary amino acid intake: tissue taurine responses in nursing and adult rats. 377 25

Taurinuria is characteristic of the immature rat. The excessive taurine loss could be the result of brush border or basal lateral membrane immaturity. The beta-amino acid, taurine, and D-glucose were examined using isolated brush border membrane vesicles (BBMV), slices and tubules prepared from 28-day-old rats. In BBMV, taurine accumulation was inversely proportional to osmolarity, indicating uptake rather than binding, and taurine accumulation was Na+-dependent. BBMV from 28-day rats did not accumulate D-glucose to the same degree as in adult BBMV, and the initial rate of uptake was slower. Taurine uptake had a similar Km and Vmax in BBMV from immature rats. Despite similarities in the kinetics of taurine uptake, higher urinary taurine concentrations are found in younger rats. The efflux of taurine from slices and tubules was much slower than in adults and probably accounts for the taurinuria of young animals. A diet low in methionine and taurine (LTD) given for seven days resulted in a lower excretion and fractional excretion of taurine than in animals fed a normal sulfur amino acid diet (NTD). A high-taurine diet (HTD) causes excessive taurinuria. These patterns of excretion are reflected at the brush border membrane surface with greater uptake after the LTD and reduced uptake after the HTD. A kinetic analysis of adult and 28-day-old animal BBMV reveals that the Vmax of accumulation is altered by diet, whereas the Km remains unchanged. The Vmax is higher in BBMV from LTD animals and lower in BBMV from HTD animals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Divergent membrane maturation in rat kidney: exposure by dietary taurine manipulation. 403 Feb 27

The plasma amino-acid levels in infants of low birth weight fed on expressed human milk and on a proprietary breast-milk substitute, S26, with a protein intake of not more than 4.5 g/kg/day were compared with those in infants fed on an evaporated milk formula whose protein intake ranged from 6.15 to 12.3 g/kg/day, as well as with normal infants on normal feeds and protein intake. In general, there was little difference between the levels in infants of low birth weight and in normal infants on the same protein intake. The five infants of low birth weight on high protein intake had generally higher levels of plasma amino-acids compared with the group on the lower protein intake, and in particular the levels of tyrosine, phenylalanine, methionine, and cystathionine could be extremely high. Apart from methionine these high levels may be the result both of a reduction in activity of the enzymes involved in the metabolism of these amino-acids, due to the immaturity of the infant, and of the increased stress of a high protein intake. In view of a possible long-term effect of abnormally high plasma amino-acid levels it is suggested that the protein intake of infants of low birth weight should not exceed 6 g/kg/day.
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PMID:Protein intake and plasma amino-acids of infants of low birth weight. 517 87

The amino acid requirements of the parenterally fed neonate are poorly defined. Newborn infants are at risk for amino acid deficiency and toxicity, due to lack of small intestinal metabolism and metabolic immaturity. We discuss recent evidence that identifies inadequacies of commercial amino acid solutions with respect to the balance and quantity of aromatic amino acids, and sulphur amino acids. We present data demonstrating that impaired small intestinal metabolism (or lack of first pass metabolism) alters the whole body requirement for methionine, threonine, and arginine, and discuss the potential adverse effects of excess or inadequate parenteral amino acid intake.
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PMID:Current total parenteral nutrition solutions for the neonate are inadequate. 1092 77

Monocytes as antigen-presenting cells play an important role in host defence. There are several cytokines affecting monocyte function. We demonstrate that both adult and cord blood monocytes constitutively express hepatocyte growth factor (HGF) receptor, MET. HGF significantly down-regulated MET expression of adult blood monocytes, compared with cord blood monocytes, when cultured either in RPMI-1640 containing 10% FBS or serum-free medium. Surface levels of MET correlated with c-met mRNA levels both in adult and cord blood when cultured. MET expression was down-regulated by treating with actinomycin D or cycloheximide. HGF stimulated DNA synthesis of adult monocytes, but not cord blood. HGF enhanced antigen-presenting capacity of adult blood monocytes but not cord blood monocytes. HGF up-regulated HLA class I expression in adult monocytes but not in cord blood monocytes. The current results suggest that the failure of cord blood monocytes to respond to HGF may be responsible, in large part, for their functional immaturity.
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PMID:Differential responsiveness of cord and adult blood monocytes to hepatocyte growth factor. 1152 13

Autosomal recessive mutations in the RARS2 gene encoding the mitochondrial arginyl-transfer RNA synthetase cause infantile-onset myoencephalopathy pontocerebellar hypoplasia type 6 (PCH6). We describe 2 sisters with novel compound heterozygous RARS2 mutations who presented perinatally with neurologic features typical of PCH6 but with additional features including cardiomyopathy, hydrops, and pulmonary hypoplasia and who died at 1 day and 14 days of age. Magnetic resonance imaging findings included marked cerebellar hypoplasia, gyral immaturity, punctate lesions in cerebral white matter, and unfused deep cerebral grey matter. Enzyme histochemistry of postmortem tissues revealed a near-global cytochrome c oxidase-deficiency; assessment of respiratory chain enzyme activities confirmed severe deficiencies involving complexes I, III, and IV. Molecular genetic studies revealed 2 RARS2 gene mutations: a c.1A>G, p.? variant predicted to abolish the initiator methionine, and a deep intronic c.613-3927C>T variant causing skipping of exons 6-8 in the mature RARS2 transcript. Neuropathologic investigation included low brain weights, small brainstem and cerebellum, deep cerebral white matter pathology, pontine nucleus neuron loss (in 1 sibling), and peripheral nerve pathology. Mitochondrial respiratory chain immunohistochemistry in brain tissues confirmed an absence of complexes I and IV immunoreactivity with sparing of mitochondrial numbers. These cases expand the clinical spectrum of RARS2 mutations, including antenatal features and widespread mitochondrial respiratory chain deficiencies in postmortem brain tissues.
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PMID:Neuropathologic Characterization of Pontocerebellar Hypoplasia Type 6 Associated With Cardiomyopathy and Hydrops Fetalis and Severe Multisystem Respiratory Chain Deficiency due to Novel RARS2 Mutations. 2608 69