Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 5-year-old girl with Rubinstein-Taybi syndrome (RTS) was scheduled for ophthalmic surgery under general anesthesia. RTS is a well-defined syndrome with facial abnormalities including a high palate and micrognathia, broad thumbs and big toes, and mental retardation as main clinical features, which may be complicated with repeated respiratory infections, cardiac anomalies, and so on. Anesthesia was uneventfully induced and maintained with the inhalation of oxygen, nitrous oxide and sevoflurane. Special attention was paid to the possibilities of the difficult airway, aspiration pneumonia and cardiovascular dysfunction during anesthesia. No complications were observed throughout the perioperative procedures.
 ...
PMID:[General anesthesia for an infant with Rubinstein-Taybi syndrome]. 928 67

Obstructive sleep apnoea episodes have been reported repeatedly in Down's syndrome (DS) patients as a consequence of the presence of predisposing malformations or intercurrent pathology of the upper airways. There are no data on respiratory patterns of uncomplicated Down's syndrome subjects. In order to evaluate the eventual effects of central nervous system (CNS) impairment on respiration in DS, we studied the respiratory patterns during sleep of a group of 10 DS subjects, aged 8.6-32.2 y, without relevant upper airway pathology. In order to control the possible effects of sleep structure and mental retardation on the results obtained, we compared the findings in DS with those obtained from a group formed by subjects affected by fragile X syndrome (six males and one female, aged 10.0-15.42 y) another genetically determined type of mental retardation. Sleep structure was similar in both groups; however, DS subjects showed significantly higher indices of central sleep apnoea and of oxygen desaturation than fragile X patients (P < 0.005). As far as DS individuals were considered, a significant preponderance of central, as opposed to obstructive, sleep apnoeas was found (89.4% vs. 9.4%, respectively; 1.2% were mixed) which showed a significant age-related increase. Central respiratory pauses were mostly preceded by sighs, which occurred more frequently during sleep stages 1 and REM, and were often organized in long sequences of periodic-like breathing. During REM sleep, they were less frequently preceded by sighs and by body movements than during NREM sleep. Obstructive sleep apnoeas occurred more often during REM sleep and were more rarely preceded by sighs or by body movements. Both central and obstructive apnoeas induced significant oxygen desaturation in 50-69.6%. Sleep structure was not significantly modified by apnoeas and oxygen desaturation. We hypothesize that the increase in central sleep apnoeas is related to a dysfunction of the central respiratory control at a brainstem level in DS.
 ...
PMID:Respiratory patterns during sleep in Down's syndrome:importance of central apnoeas. 937 33

In Down syndrome (DS), oxidative DNA-damage may play a role in the pathogenesis of characteristic mental retardation and precocious dementia of Alzheimer type. We measured the oxidized nucleoside, 8-hydroxy-2'-deoxyguanosine (8-OHdG), in nuclear DNA (nDNA) isolated from four different regions of cerebral cortex and cerebellum in 10 adult DS and 10 Alzheimer's disease (AD) patients compared to normal controls. Levels of 8-OHdG in post-mortem brain tissue were investigated by means of high-performance liquid chromatography with electrochemical detection. There was no significant increase in DS and AD compared to controls in any of the brain regions. Highest amounts of 8-OHdG were in temporal cortex in DS (180.0 +/- 9.6 nmol/g wet weight tissue), AD (172.4 +/- 14.6 nmol/g wet weight tissue) and controls (183.4 +/- 12.7 nmol/g). We conclude that the results provide evidence against an increased reactive oxygen species (ROS) induced damage to nDNA in DS and AD.
 ...
PMID:Evidence against increased oxidative DNA-damage in Down syndrome. 940 88

To characterize the energy metabolism in individuals with mental retardation (MRs), we measured energy cost at several physical activity levels (basal, supine, sitting, standing, and walking at 30, 50 and 70 m/min), maximal oxygen consumption (Vo2max), and body composition in 23 male MRs and the same number of volunteer male controls. Both groups were individually matched for age, body height, and body weight. Energy cost was measured by the Douglas bag technique. The recently developed sulfur hexafluoride (SF6) dilution technique was employed for measuring body composition. In addition, 3-dimensional accelerometry was used for evaluating body movements, and plasma indices of macronutrients were also measured. The energy cost of MRs, when sitting, standing, and walking at 30 and 50 m/min, was significantly higher than that of controls (p < 0.05), while the basal and resting metabolic rates were similar in both groups. Vo2max was significantly lower (p < 0.05) in MRs than controls. Accelerometry demonstrated excessive movement by MRs, which may explain their higher energy cost of exercise. In contrast, no significant difference was observed in percent body fat or lean body mass. Concentrations of plasma total cholesterol, triacylglycerols and albumin were significantly lower in MRs as compared with the controls. Our findings suggest that MRs are burdened with an energy metabolism less economical than non-MRs. Limited physical activity in their daily life may be the cause. These characteristics of MRs' energy metabolism should be considered for planning their proper dietary schedules and physical activity programs.
 ...
PMID:Characteristics of energy metabolism in males with mental retardation. 959 Dec 42

Total body bone mineral density was measured by dual energy X-ray absorptiometry in 52 children who were very low birth weight (VLBW) infants without cerebral palsy and mental retardation (postconceptional age, from 10 mo to 6 y and 6 mo). VLBW infants in this study seemed to show compensatory acceleration of total body bone development, catching up with the control group during early childhood. However, in VLBW infants with at least one of the three factors such as total parenteral nutrition for 1 week or more, assisted ventilation for 1 week or more, or oxygen therapy for 28 d or more in their early stage after birth, adequate mineral supplementation might be especially important for long-term bone development.
 ...
PMID:Total body bone development during early childhood in very low birth weight infants without cerebral palsy and mental retardation. 967 7

Hereditary argininemia manifests as neurological disturbance and mental retardation, features not observed in other amino acidemias. The cytotoxic effect of a high concentration of L-arginine (L-Arg) was investigated using NB9 human neuroblastoma cells (NB9), which express neuronal nitric oxide synthase (nNOS). When the concentration of L-Arg in the medium increased from 50 microM to 2 mM after incubation for 48 hr, the intracellular concentration of L-Arg increased from 68.0 +/- 1 pmol/10(6) cells to 1310.0 +/- 5 pmol/10(6) cells and that of L-citrulline (L-Cit) from undetectable levels to 47.1 +/- 0.2 pmol/10(6) cells (mean +/- SD of three independent analyses). This increase in intracellular L-Arg levels caused a decrease in NOS activity by approximately 71%. Flow cytometric analysis showed that reactive oxygen species (ROS) are produced in NB9 exposed to 2 mM L-Arg. The production of ROS was abolished by a NOS inhibitor, NG-nitro-L arginine-methylester. Production of ROS was also observed when NB9 were treated with L-Cit for 48 hr. To investigate the effect of L-Cit on the activity of NOS, a kinetic study on nNOS was conducted using cellular extracts from NB9. The apparent Km value of nNOS for L-Arg was 8.4 microM, with a Vmax value of 8.2 pmol/min/mg protein. L-Cit competitively inhibited NOS activity, as indicated by an apparent Ki value of 65 nM. These results suggest that L-Cit formed by nNOS in L-Arg-loaded neuronal cells inhibits NOS activity and nNOS in these L-Arg-loaded cells functions as a NADPH oxidase to produce ROS, which may cause neurotoxicity in argininemia.
 ...
PMID:High concentration of L-arginine suppresses nitric oxide synthase activity and produces reactive oxygen species in NB9 human neuroblastoma cells. 974 7

We present a child with Lenz dysplasia associated with panhypopituitarism. Lenz dysplasia is characterized by small eyeball, small head, hydronephrosis, cleft lip and palate, and mental retardation. A 12 month-old boy with Lenz dysplasia was scheduled for plasty of the lip and basis of the nasal cavity under general anesthesia. We had to pay attention for airway management and hormone supplementation. Anesthesia was induced with sevoflurane and nitrous oxide in oxygen. Tracheal intubation was facilitated with vecuronium bromide. We had no difficulty in airway management. Since this patient could not release enough endogenous cortisol in response to the stress of surgery, we supplemented hydrocortisone after anesthesia induction. Urine output and serum electrolyte concentrations were carefully monitored during surgery because of the impaired ADH response. We encountered no complications in the anesthetic management of this patient.
 ...
PMID:[Anesthetic management of a child with Lenz dysplasia associated with panhypopituitarism]. 978 90

The survival rate of very preterm, low birth weight infants (weighing less than 1500 g) is 85 per cent in the USA and is ever increasing, while 42 to 75 per cent of extremely premature infants (weighing 751-1000 g) survive. Of great concern is the lack of consistent decrease in neurological syndromes and associated visual impairments. Because of short gestations, these infants have not had time to accrue up to 80 per cent of magnesium normally present at term. These very preterm infants are at highest risk for cerebral hypoxia/ischemia (H/I), intracranial hemorrhage (ICH), periventricular leukomalacia (PVL) or cystic PVL (CPVL), and possible sequelae, cerebral palsy (CP) and mental retardation (MR). These syndromes are associated with damage to optic structures and the visual pathways which traverse the brain. Visual defects are common in surviving preterm infants. Increased levels of harmful neurochemical mediators that have been reported in these conditions include oxygen free radicals, excitatory amino acids, tumor necrosis factor-alpha (TNF-a), and thromboxane A2 (TXA2) which are aggravated in magnesium deficiency and may be ameliorated by magnesium. We review the published data concerning the effects of prenatal magnesium supplementation on ICH, CPVL, CP and MR and available reports concerning survival. Further considerations on the safety and efficacy of magnesium sulphate administration given prenatally to the preterm neonate await the outcome of three trials that are continuing for more than a year on three continents.
 ...
PMID:The possible role of magnesium in protection of premature infants from neurological syndromes and visual impairments and a review of survival of magnesium-exposed premature infants. 1048 76

Twenty-nine high-risk preterm born children, from a cohort with cerebral blood flow (CBF) measurements in the first 2 d of life, were examined prospectively at the age of 5.5-7 y neurologically, neuropsychologically and by magnetic resonance imaging (MRI). They were compared to 57 control children in terms of neurology and neuropsychology. Abnormal MRI was found in 19 children. Low oxygen delivery to the brain was found in 63% of them, in contrast to 12.5% in those with normal MRI, indicating neonatal hypoxia-ischemia as an important factor. The MRI abnormalities were mainly periventricular lesions (n = 19), especially periventricular leucomalacia (PVL, n = 17). Three of the very preterm children had severe cerebellar atrophy in addition to relatively mild periventricular abnormalities. MRI showed specific morphological correlates for the major disabilities, e.g. spastic CP (involvement of motor tracts), mental retardation (bilateral extensive white matter reduction or cerebellar atrophy) and severe visual impairment (severe optic radiation involvement). A morphological correlate for minor disabilities, i.e. functional variations in motor performance or intelligence, was not found, with the exception that symptoms of attention deficit hyperactivity disorder were related to mild MRI abnormalities. This could mean that with respect to cognitive functions, mild or unilateral periventricular MRI lesions could be compensated. However, as among preterms without mental retardation (n = 19), IQ was generally and significantly lower than in the control group; other, more chronic pathogenetic factors, not detectable by MRI alone, may play a role.
 ...
PMID:Brain lesions in preterms: origin, consequences and compensation. 1050 92

Down's syndrome (DS), occurring in 0.8 out of 1,000 live births, is a genetic disorder in which an extra portion of chromosome 21 leads to several abnormalities. With respect to the nervous system, it causes mental retardation. It is conceived that abnormal neuronal cell death in development is involved, but there is no direct evidence yet. In addition to developmental brain abnormalities, almost all DS brains over 40 years old manifest a similar pathology to Alzheimer's disease (AD), including the presence of senile plaques (SP) and neurofibrillary tangles (NFT). Although there was a debate to segregate dementia from underlying mental retardation, at least some portion of DS patients exhibit deteriorated mental status with aging. The mechanism underlying these abnormalities at the molecular level remains to be elucidated. Recently there have been several reports suggesting abnormalities reflecting increased risk to apoptosis in DS brains. Increased expression of several apoptosis-related genes (p53, fas, ratio of bax to bcl-2, GAPDH) in DS brains has been reported. Cultured neurons from both patients and model animals are reportedly more vulnerable to apoptosis. Overproduction of reactive oxygen species and its causative roles for increased apoptosis in DS tissues are suggested. One possible hypothesis is an increased susceptibility to apoptosis due to p53 overactivation in DS brains. A beta 42, a critical peptide for AD pathology from amyloid precursor protein (APP), can be detected in DS brains. A beta 42 is deposited in SP from an early stage, suggesting common molecular mechanisms in DS and AD. Animal models for DS are important in the search of molecular mechanisms. Several types of models are now available. Future DS studies are expected to integrate information from animal models and human tissues.
 ...
PMID:Neuronal cell death in Down's syndrome. 1066 70


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>