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

Endemic cretinism is the most severe manifestation of dietary iodine deficiency. Two forms of the syndrome are traditionally described: neurological and myxoedematous. Although this classification highlights the important neurological sequelae of the disorder it implies that myxoedematous cretins have an alternative mechanism. Further, the nature of the neurological deficit associated with both types of endemic cretinism has received scant attention in recent times considering that it remains a common disorder in many parts of the world. The nature and extent of the neurological deficit found in endemic cretinism was investigated in 104 cretins from a predominantly myxoedematous endemia in western China and in 35 cretins from central Java, Indonesia, a predominantly neurological endemia. We found a similar pattern of neurological involvement in nearly all cretins from both endemias, regardless of type (myxoedematous or neurological), and of current thyroid function. Hallmarks of the neurological features included mental retardation, pyramidal signs in a proximal distribution and extrapyramidal signs. Many patients exhibited a characteristic gait. This probably reflected pyramidal and extrapyramidal dysfunction, although joint laxity and deformity were important contributing factors. Other frequently encountered clinical features were squint, deafness, and primitive reflexes. Cerebral computerized tomography (CT) revealed basal ganglia calcification in 15 of 50 subjects. The presence of basal ganglia calcification was confined to cretins with severe hypothyroidism. Otherwise, cerebral CT scanning demonstrated only minor abnormalities which did not contribute to the localization of the clinical deficits. We conclude that the same neurological disorder is present in both types of endemic cretinism reflecting a diffuse insult to the developing fetal nervous system. These clinical findings support the concept of maternal and fetal hypothyroxinaemia, arising from severe iodine deficiency, as the primary pathophysiological event in endemic cretinism. Differences between the two types of cretinism may be explained by continuing postnatal thyroid hormone deficiency in the myxoedematous type, which results in impaired growth, skeletal retardation and sexual immaturity.
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PMID:The neurology of endemic cretinism. A study of two endemias. 204 52

Neonatal diabetes mellitus is defined as hyperglycemia detected in the first month of life of more than 2 weeks' duration, requiring insulin treatment. It is extremely uncommon (1/500,000 neonates) and is permanent in only 30% of cases. Several hypotheses concerning its etiology have been postulated, such as pancreatic immaturity, paternal uniparental isidisomy of chromosome 6, and the existence of a gene located in the 6 q 22-23 chromosome region subjected to imprinting and exclusively of paternal expression. The management of these patients is usually difficult. These neonates are underweight for their gestational age, and neither anti-insulin antibodies nor anti-islets are detected. We studied a neonate hospitalized because of low weight for his gestational age with dimorphic features and hyperglycemia since the 17 th day of life. Clinical and anatomical follow-up has been periodically performed to the present date. The child presents permanent neonatal diabetes with negative antibodies. Although various insulin patterns have been used since the onset of the syndrome, management remains difficult. The child presents hypothyroidism, bilateral neurosensory deafness, bilateral congenital cataract, myopia, dimorphic features, congenital stridor and slow weight-stature curve. The results of muscle biopsy and metabolic studies were normal. Wolfram's syndrome and mitochondrial diabetes were ruled out. This is an exceptional case of permanent neonatal diabetes associated with other malformations corresponding to no known syndromic patterns.
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PMID:[Permanent neonatal diabetes associated with other anomalies]. 1133 81

Profoundly deaf children who use a cochlear implant (CI) provide a unique opportunity to investigate the effects of auditory sensory deprivation on the maturing human central nervous system. Previous results suggest that children fitted with a CI show evidence of altered auditory cortical maturation, based on evoked potentials. This altered maturation was characterized by both latency delays and morphological changes in the cortical auditory evoked potentials (AEPs). Based on prolonged P(1) latencies compared to age-matched normal-hearing (NH) peers, these data suggested a delayed maturation nearly equivalent to the period of deafness. However, rates of maturation for this AEP peak were essentially the same in NH and CI children. This suggests that, given enough time, the AEPs of CI children would assume the characteristic morphology found in older NH teens and NH adults. However, the data also indicated a substantial alteration of the typical set of obligatory P(1)-N(1b)-P(2) peaks, specifically related to the absence of the N(1) potential. Recent analyses of more extensive sets of longitudinal and cross-sectional data indicate that even after many years of implant use, the AEPs of CI users in their late teens remain very different from those of their NH peers. The P(1) peak latency remains prolonged and P(1) amplitude remains much larger in CI users than in age-matched NH teens. These findings suggested that age-related changes in the P(1) peak are completed by 12 years of age. In addition, the normal N(1b) peak fails to emerge in virtually all of the CI children tested in our laboratory. A major new interpretation of the abnormal maturation of AEP waveforms in CI children is presented. It is based on direct evidence showing that a persistent immaturity of the superficial layer axons has persistent negative effects on the generation of the N(1b) and, consequently, on the morphology of the AEPs. A comparison of scalp-recorded AEPs from implanted children with local field potentials measured from the cortical surface in deaf white kittens suggests the effects of deafness and CI use are similar across these mammalian species. For both species, a period of profound deafness followed by CI stimulation reveals a substantial immaturity in cortical activation even after a period of electrical stimulation by the CI.
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PMID:Of kittens and kids: altered cortical maturation following profound deafness and cochlear implant use. 1184 64

Sex determination and differentiation depend on differentiation of the indifferent gonad to the testis or ovary, which leads to masculine or feminine differentiation of internal and external genitalia. Recently, genes involved in this cascade have been identified with the advance of molecular genetical analysis. XY gonadal dysgenesis, this is a condition that has XY chromosome but is characterized by the indifferent testis. There are complete and incomplete types. Complete type has bilateral gonads of cordee, does not show physical characteristics of Turner's syndrome, has the uterus and ovaries, and has the vagina in female type, though the external genitalia are immature. Incomplete type is characterized by bilateral testicular hypoplasia(male pseudohermaphroditism) or unilateral testicular hypoplasia and bilateral restiform gonads(mixed gonadal dyspenesis), and the sexuality of the external genitalia is unclear. XX gonadal dysgenesis, complete type is characterized by bilateral restiform gonads, female type internal and external genitalia and sexual immaturity, though it does not show any characteristics of Turner's syndrome. It presents hypergonadotropic hypogonadism endocrinologically. It shows a familial incidence with autosomal recessive inheritance, and sensorineural deafness is accompanied in some cases. Incomplete type has rudimentary ovaries and show a varying degree of secondary sexual characteristics. Mixed dysgenesis, many cases have XO/XY mosaic and this dysgenesis is characterized by unilateral hypoplastic testis and contralateral restiform gonad. It may occur in cases of incomplete type XY gonadal dysgenesis. Trisomy X, cases of trisomy X have three X chromosomes as this term indicates. There are some cases of polisomy with four or more X chromosomes. The frequency of trisomy X has been reported to be one in 1,000 births of female, which means that it is a relatively common chromosomal aberration. It has been reported that about 20% of cases of trisomy X have sexual dysfunction, predominantly with primary amenorrha.
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PMID:[XY type gonadal dysgenesis, trisomy X and variants]. 1496 37

Variability in speech perception abilities after years of cochlear implant use could reflect differences in central auditory processing of the electrical input provided. Cortical responses were measured in 23 experienced pediatric cochlear implant users who were 12.3+/-3.1 years of age at testing and had used their implants for 6.0+/-2.9 years. All had prelingual onset of deafness. An observer identified blind three types of cortical waveforms ranging from those similar to previous reports to more atypical responses. Children displaying atypical types of responses were implanted at a wide range of ages and had significantly poorer behavioral speech perception scores (P<0.05) than their peers with expected waveforms. Results suggest a persistent immaturity and/or abnormal organization in the auditory cortex in some children.
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PMID:Atypical cortical responses underlie poor speech perception in children using cochlear implants. 1631 51

The "wait and see" approach in acute otitis media (AOM), consisting of postponing the antibiotic administration for a few days, has been advocated mainly to counteract the increased bacterial resistance in respiratory infections. This approach is not justified in children less than 2 years of age and this for several reasons. First, AOM is an acute inflammation of the middle ear caused in about 70% of cases by bacteria. Redness and bulging of the tympanic membrane are characteristic findings in bacterial AOM. Second, AOM is associated with long-term dysfunction of the inflamed eustachian tube (ET), particularly in children less than 2 years of age. In this age group, the small calibre of the ET together with its horizontal direction result in impaired clearance, ventilation and protection of the middle ear. Third, recent prospective studies have shown poor long-term prognosis of AOM in children below 2 years with at least 50% of recurrences and persisting otitis media with effusion (OME) in about 35% 6 months after AOM. Viruses elicit AOM in about 30% of children. A prolonged course of AOM has been observed when bacterial and viral infections are combined because viral infection is also associated with ET dysfunction in young children. Bacterial and viral testing of the nasopharyngeal aspirate is an excellent tool both for initial treatment and recurrence of AOM. Antibiotic treatment of AOM is mandatory in children less than 2 years of age to decrease inflammation in the middle ear but also of the ET particularly during the first episode. The best choice is amoxicillin because of its superior penetration in the middle ear. Streptococci pneumoniae with intermediary bacterial resistance to penicillin are particularly associated with recurrent AOM. Therefore the dosage of amoxicillin should be 90 mg/kg per day in three doses. In recurrent AOM with beta-lactamase-producing bacilli, amoxicillin should be associated with clavulanic acid at a dose of 6.4 mg/kg per day. The duration of the treatment is not established yet but 10 days is reasonable for a first episode of AOM. OME may be a precursor initiating AOM but also a complication thereof. OME needs a watchful waiting approach. When associated with deafness for 2-3 months in children over 2 years of age, an antibiotic should be given according to the results of the bacterial resistance in the nasopharyngeal aspirate. The high rate of complications of tympanostomy tube insertion outweighs the beneficial effect on hearing loss. The poor results of this procedure are due to the absence of effects on ET dysfunction. Pneumococcal vaccination has little beneficial effects on recurrent AOM and its use in infants needs further studies. Treatment with amoxicillin is indicated in all children younger than 2 years with a first episode of AOM presenting with redness and bulging of the tympanic membrane. Combined amoxicillin and clavulanic acid should be given in patients with beta-lactamase-producing bacteria. The duration of treatment is estimated to be at least 10 days depending on the findings by pneumo-otoscopy and tympanometry. Bacterial and viral testing of the nasopharyngeal aspirate is highly recommended particularly in children in day care centres as well as for regular follow-up. The high recurrence rate is due to the long-lasting dysfunction of the eustachian tube and the immune immaturity of children less than 2 years of age.
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PMID:What is new in otitis media? 1736 73