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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A decrease in the number and density of neurons is the most common phenotype in the brains of Down syndrome (DS) patients, causing mental retardation. Studies using primary cultured neurons from DS patients or from model mice have suggested that a defect in metabolism of reactive oxygen species, or diminished levels of glutathione, causes mitochondrial and caspase-mediated neuronal apoptosis in vitro. However, it is not well documented whether neuronal apoptosis also occurs in immature DS neurons, owing to the difficulty in isolating or identifying neuronal stem cells in human or mouse fetuses. Here we utilized an in vitro model system for neuronal differentiation, with mouse embryonic stem cells containing human chromosome 21 (TT2F/hChr.21) to examine the effect of an additional hChr.21 on the early phases of neurogenesis. The differentiation profile of TT2F/hChr.21 cells was essentially the same as those of parental TT2F ES cells. In differentiations of both TT2F and TT2F/hChr.21 cells, high level of apoptosis was observed in neuronal stem cells, but the rate of apoptosis in TT2F/hChr.21 cells was significantly higher than that of parental cells. These results suggest that quantitative changes in the level of apoptosis in DS neuronal stem cells may account for the reduction of neuronal number and density in the DS brain.
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PMID:Elevated apoptosis in pre-mature neurons differentiated from mouse ES cells containing a single human chromosome 21. 1245 81

The haemopoietic system in the developing mammal is very sensitive to the damaging effects of ionizing radiation. Epidemiological studies have established a strong association between obstetric exposure to diagnostic radiation and an increase in the incidence of childhood leukaemia and between low dose gamma irradiation during the early fetal period and mental retardation in children. It has been suggested that insufficient oxygen supply to the developing brain due to radiation induced damage to fetal haemopoietic tissue has a role in inducing the severe mental retardation observed in the Japanese children exposed to atom bomb radiation in utero. Experimental studies have shown that X- and gamma irradiation of pregnant mice with <1 Gy during the late organogenesis or fetal period caused chromosome damage and significant depletion in the fetal haemopoietic progenitor cells and led to haematological disorders in the adults. The present paper reviews the experimental findings on the effect of pre-natal irradiation on the fetal haemopoietic system and its long-term consequences.
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PMID:Radiosensitivity of the developing haemopoietic system in mammals and its adult consequences: animal studies. 1281 21

A 5-year-old boy with Williams syndrome received open reduction of fracture of the antebrachium twice. He had been diagnosed as having Williams syndrome with some characteristic symptoms, including elfin face, mental retardation and primary pulmonary hypertension. Williams syndrome has a tetrad of cardiovascular disease, elfin face, mental retardation and hypercalcemia. Operations were performed twice under general anesthesia. Airway management with mask technique was easily performed. Tracheal intubation was accomplished successfully. Anesthesia was induced with propofol, fentanyl, and vecuronium, and maintained with propofol, fentanyl and the inhalation of oxygen with nitrous oxide. Both anesthetic courses were uneventful and he was discharged without any complications. Special anesthetic considerations should be taken for difficulties of intubation, management of circulatory system, malignant hyperthermia, and hypercalcemia in this syndrome.
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PMID:[Two occasions of anesthetic management for a patient with Williams syndrome]. 1367 82

Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive syndrome, characterized by severe growth failure and congenital anomalies (for example dysgenesis, mental retardation, renal and cardiac defects, and various malformation). SLOS results from error of a cholesterol enzyme and generalized cholesterol deficiency. This report describes our experience of a patient with SLOS and thrombocytopenia who underwent anesthesia twice for surgical procedures in a year. The patient received drip platelet transfusion for thrombocytopenia before operations. Anesthesia was induced with inhalation of oxygen, nitrous oxide and sevoflurane, and maintained with oxygen, propofol, fentanyl and low concentrations of sevoflurane. Airway was maintained with laryngeal mask airway. Complications were not seen in this case. One of the problems in anesthetic management of SLOS is difficult intubation because of the typical dysmorphic facial features such as micrognathia, cleft palate and abnormal tongue. We thought that laryngeal mask airway was useful and safe for SLOS patients. Two cases of malignant hyperthermia were reported in anesthetic management of SLOS by using halothane or suxamethonium. In this case, the anesthetic maintenance was mostly with propofol and fentanyl. Malignant hyperthermia did not occur but sevoflurane was used at low concentrations. SLOS presents various problems with anesthetic management and we have to administer general anesthesia carefully.
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PMID:[Anesthetic management of a patient with Smith-Lemli-Opitz syndrome complicated with thrombocytopenia]. 1466 77

Mitochondrial DNA (mtDNA) deletion affecting 4977 base pairs (mtDNA4977), the most common mtDNA mutation in humans, was analysed in brain specimens (frontal, temporal, and cerebellar cortices, caudate nucleus, thalamus, and hippocampus) and in other tissues (blood clot, liver, kidney, heart, and muscle) taken at autopsy of deceased neonates. mtDNA4977 deletion determined by polymerase chain reaction (PCR) could be demonstrated in each neonatal sample, however, quantity of mtDNA4977 deletion was less in the newborn samples than in those of the elderlies. Results obtained suggest that contrary to certain data mtDNA4977 deletion can be present in neonates. The mtDNA4977 deletion could be generated by perinatal hypoxia or temporary oxygen oversaturations during the intensive care of the neonates, as the mtDNA is sensitive to oxidative damage. In combination with other factors an additional causative role of mtDNA4977 deletion reported here cannot be ruled out in development of cerebral palsy or mental retardation of unknown origin often seen in neonates underwent neonatal intensive care procedures.
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PMID:Mitochondrial DNA4977 deletion in brain of newborns died after intensive care. 1471 Oct 30

It is well known that neonatal hypoxic-ischemic brain injury leads to mental retardation and deficits in cognitive abilities such as learning and memory in human beings. The ameliorative effect of erythropoietin (Epo) on experimental hypoxic-ischemic brain injury in neonatal rats has been recently reported. However, the effect of Epo on cognitive abilities in the hypoxic-ischemic brain injury model is unknown. The aim of this study is to investigate the effects of Epo on learning-memory, behavior and neurodegeneration induced by hypoxia-ischemia. Seven days old Wistar Albino rat pups have been used in the study (n = 28). Experimental groups in the study were: (1) saline-treated hypoxia-ischemia group, (2) Epo-treated (i.p., 1000 U/kg) hypoxia-ischemia group, (3) sham-operated group, (4) control group. In hypoxia-ischemia groups, left common carotid artery was ligated permanently on the seventh postnatal day. Two hours after the procedure, hypoxia (92% nitrogen and 8% oxygen) was induced for 2.5 h. Epo was administered as a single dose immediately after the hypoxia period. When pups were 22 days old, learning experiments were performed using Morris water maze. On the 20th week, when brain development is accepted to be complete, learning experiments were repeated. Rats were then perfused and brains removed for macroscopic and microscopic evaluation. Epo treatment immediately after hypoxic-ischemic insult significantly improved long-term neurobehavioral achievements when tested during the subsequent phase of brain maturation and even into adulthood. Histopathological evaluation demonstrated that Epo also significantly diminished brain injury and spared hippocampal CA1 neurons. In conclusion, Epo administrated as a single dose immediately after neonatal hypoxic-ischemic insult provides benefit over a prolonged period in the still developing rat brain. Since the wide use of Epo in premature newborns, this agent may be potentially beneficial in treating asphyxial brain damage in the perinatal period.
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PMID:Erythropoietin improves long-term spatial memory deficits and brain injury following neonatal hypoxia-ischemia in rats. 1521 9

An eight-year-old boy with Cornelia de Lange syndrome underwent left inguinal hernioplasty and orchiopexy under general anesthesia. The patient with Cornelia de Lange syndrome had severe primordial growth failure with muscle-skeletal system such as cleft palate, micrognathia, and micromelia of the extremities and mental retardation as well as characteristic faces such as deep supercilia, etc. We suspected difficulty of endotracheal intubation due to this syndrome. Anesthesia was induced with intravenous injection of atropine 0.1 mg and ketamine 10 mg followed by inhalation of nitrous oxide 3 l x min(-1), oxygen 3 l x min(-1), and sevoflurane 5% without any muscle relaxant. Although his neck and temporomandibular joint were stiff, his trachea was intubated orally without difficulty with a 4.5 mm ID tracheal tube using a Macintosh laryngoscope. Anesthesia was maintained uneventfully by bolus intravenous injection of ketamine 5 mg and inhalation of oxygen and sevoflurane 2-3% with mechanical ventilation. The anesthetic management in a patient with Cornelia de Lange syndrome should be carried out with careful preoperative evaluation of physical status, and especially the difficult endotracheal intubation should be kept in mind. Induction of general anesthesia with injection of ketamine followed by inhalation of sevoflurane without muscle relaxant is a safe method in Cornelia de Lange syndrome.
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PMID:[Anesthetic management in a patient with Cornelia de Lange syndrome]. 1544 85

A portable monitoring device was developed to assist in the management of children with a learning disability. The device was designed for continuous home monitoring of blood oxygen saturation, heart and respiration rates, and patient activity. It could be worn on a belt, while the patient continued normal activities. Data were stored on a multimedia card and automatically transmitted to a PC at prescribed intervals via a Bluetooth wireless link. From the PC the data were transmitted to a Web server, where the information was made available to the staff involved in the patient's care. Preliminary clinical studies were performed with nine patients (four with Down's syndrome, three with cerebral palsy and two with mental retardation). Patients and families considered the device easy to use and to wear. The monitoring device identified events of possible clinical interest. Although it was designed for monitoring children with a learning disability, it may also be useful with other groups, such as elderly people.
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PMID:A multi-functional, portable device with wireless transmission for home monitoring of children with a learning disability. 1549 89

Approximately 10% of newborns are born prematurely. Of these children, more than 10% will sustain neurological injuries leading to significant learning disabilities, cerebral palsy, or mental retardation, with very low birth weight infants having an even higher incidence of brain injury. Whereas intraventricular hemorrhage was the most common form of serious neurological injury a decade ago, periventricular white matter injury (PWMI) is now the most common cause of brain injury in preterm infants. The spectrum of chronic PWMI includes focal cystic necrotic lesions (periventricular leukomalacia; PVL) and diffuse myelination disturbances. Recent neuroimaging studies support that the incidence of PVL is declining, whereas diffuse cerebral white matter injury is emerging as the predominant lesion. Factors that predispose to PVL include prematurity, hypoxia, ischemia, and inflammation. It is believed that injury to oligodendrocyte (OL) progenitors contributes to the pathogenesis of myelination disturbances in PWMI by disrupting the maturation of myelin-myelin-forming oligodendrocytes. Other potential mechanisms of injury include activation of microglia and axonal damage. Chemical mediators that may contribute to white matter injury include reactive oxygen (ROS) and nitrogen species (RNS), glutamate, cytokines, and adenosine. As our understanding of the pathogenesis of PWMI improves, it is anticipated that new strategies for directly preventing brain injury in premature infants will evolve.
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PMID:Emerging concepts in periventricular white matter injury. 1569 97

Progressive muscular dystrophy may produce abnormal reactions to several drugs. There is no consensus of opinion regarding the continuous infusion of propofol in patients with progressive muscular dystrophy. We successfully treated 2 patients with progressive muscular dystrophy who were anesthetized with a continuous infusion of propofol. In case 1, a 19-year-old, 59-kg man with Becker muscular dystrophy and mental retardation was scheduled for dental treatment under general anesthesia. General anesthesia was maintained by a continuous infusion of 6-10 mg/kg propofol per hour and an inhalational mixture of 67% nitrous oxide and 33% oxygen. No complications were observed during or after the operation. In case 2, a 5-year-old, 11-kg boy with Fukuyama type congenital muscular dystrophy and slight mental retardation was scheduled for dental treatment under general anesthesia. General anesthesia was maintained with a continuous infusion of 6-12 mg/kg propofol per hour and an inhalational mixture of 0.5-1.5% sevoflurane in 67% nitrous oxide and 33% oxygen. No complications were observed during or after the operation. It is speculated that a continuous infusion of propofol in progressive muscular dystrophy does not cause malignant hyperthermia because serum levels of creatine phosphokinase and myoglobin decreased after our anesthetic management. Furthermore, our observations suggest that sevoflurane may have some advantages in patients with progressive type muscular dystrophies other than Duchenne muscular dystrophy and Becker muscular dystrophy. In conclusion, our cases suggest that a continuous infusion of propofol for the patients with progressive muscular dystrophy is a safe component of our anesthetic strategy.
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PMID:Continuous infusion propofol general anesthesia for dental treatment in patients with progressive muscular dystrophy. 1585 43


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