Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Children who survive very preterm birth without major disability have a high prevalence of learning difficulty, attention deficit, and minor motor impairment (MMI). To determine whether these difficulties are associated with structural brain abnormalities, we studied 105 preterm children (<32 wk) at 7 y with tests of IQ and MMI (Movement ABC) and detailed magnetic resonance brain scans. Scans were assessed qualitatively for visible cerebral lesions. Volume measurements of the caudate nuclei and hippocampal formations were made. Total brain volume (TBV) was estimated from the head circumference. Qualitative assessment of the scans showed evidence of cerebral lesions in 20 (19%), which were associated with lower IQ and more frequent MMI. IQ correlated with right and left caudate volume (Spearman's rho 0.304 and 0.349; p < 0.01). This association persisted (except for verbal IQ) when caudate volume was expressed as a percentage of estimated TBV to allow for overall brain size. No significant correlations with hippocampal volumes were observed. These differences persisted when only scans from children without visible lesions on scan were considered. MMI was significantly associated only with TBV and was more common in children with evidence of thinning of the posterior corpus callosum, although most children with MMI have a normal corpus callosum. Lower IQs in children who were born preterm are related to poorer development of the caudate relative to the rest of the brain, independent of other lesions. These findings suggest abnormal brain development after perinatal injury or postnatal nutritional deficits is responsible for cognitive deficits in preterm children.
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PMID:Caudate and hippocampal volumes, intelligence, and motor impairment in 7-year-old children who were born preterm. 1476 14

Magnetic resonance imaging studies have contributed to recognize the patterns of cerebral injury related to neonatal encephalopathy (NE). We assessed whether a smaller corpus callosum (CC) explained the difference in motor performance between school-age children with NE and controls. Frontal, middle, and posterior areas of the CC were measured in 61 9-10-y-old children with NE and in 47 controls. Motor performance was determined using the Movement Assessment Battery for Children (M-ABC). Linear regression was used to assess whether differences in M-ABC between NE children and controls could be explained by CC size. The CC of 11/30 children with NE type I according to Sarnat (NE I) and 19/36 children with NE type II according to Sarnat (NE II) showed generalized or focal thinning, compared with 8/49 controls. Children with NE II had significantly smaller middle and posterior parts and total areas of the CC. Children with NE scored significantly worse on the M-ABC than controls. The reduction in size of the posterior part of the CC partly explained the mean differences on the M-ABC. Children with NE have poorer motor skills than controls, which is partly explained by a smaller size of the CC.
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PMID:Corpus callosum size in relation to motor performance in 9- to 10-year-old children with neonatal encephalopathy. 1804 16

The human placenta, characterized by the processes of passive transport and facilitated diffusion, contains numerous active transport proteins, usually located in the microvilli of the syncytiotrophoblast or in the endothelium of the capillaries of the villi. These proteins use either the energy from ATP hydrolysis or other mechanisms resulting, among others, from the formation of the maternofetal ion gradient, which facilitates the transfer of various endogenous substances or xenobiotics across the body membranes. The proteins either trigger the efflux of these substances from the fetal tissues via the placenta into the maternal bloodstream, or conversely they accumulate them in the fetal tissues. Both the placenta and the fetus are equipped with independent systems of enzymes of 1st and 2nd phase of substrate metabolism, such as CYP450, glucuronyltransferase or sulphatase. An active therapy with a wide range of drugs, often at high toxicity levels, either shortly before or during pregnancy, has naturally posed a question concerning the degree of impermeability of the placental barrier and how effectively it can be crossed, including any possible negative embryotoxic or teratogenic consequences. Such hazards seem to be quite real, as many drugs are substrates for ABC transporters. Also the placenta itself, including its structure, is subject to vast transformations during pregnancy which may be observed as the thinning of the barrier separating the maternal blood from the fetal one, from 20-30 microm in the first trimester of gestation down to 2-4 microm in the third trimester of gestation.
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PMID:Active and passive transport of drugs in the human placenta. 1994 43

Resurgence has commonly been viewed as the recovery of an extinguished instrumental behavior that occurs when an alternative behavior that has replaced it is also extinguished. Three experiments with rat subjects examined the effects on resurgence of the temporal distribution of reinforcement for the alternative behavior that is presented while the first response is being eliminated. Experiments 1 and 2 examined resurgence when rich rates of reinforcement at the onset of response elimination became leaner over sessions (i.e., forward thinning) and when lean rates became richer (i.e., reverse thinning). Both procedures weakened resurgence compared with that in a group that received the richest rate during all sessions. However, forward thinning was more effective than reverse thinning at reducing the resurgence effect. Experiment 3 found that final resurgence was eliminated when the alternative behavior was reinforced and extinguished in alternating response elimination sessions. The results are consistent with the hypothesis that reinforcer delivery during response elimination provides a contextual stimulus for the extinction of the original behavior; its removal during resurgence testing causes ABC renewal to occur. The results are less consistent with an alternative account that emphasizes the removal of response disruption caused by alternative reinforcement (Shahan & Sweeney, 2011). Other theoretical and applied implications are discussed.
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PMID:Effects of reinforcer distribution during response elimination on resurgence of an instrumental behavior. 2804 93

Reports an error in "Effects of reinforcer distribution during response elimination on resurgence of an instrumental behavior" by Scott T. Schepers and Mark E. Bouton (Journal of Experimental Psychology: Animal Learning and Cognition, 2015[Apr], Vol 41[2], 179-192). The mean R2 responding during the resurgence test in the alternating group in the lower right panel of Figure 4 was incorrect. A corrected figure is given in the correction. (The following abstract of the original article appeared in record 2015-12206-001.) Resurgence has commonly been viewed as the recovery of an extinguished instrumental behavior that occurs when an alternative behavior that has replaced it is also extinguished. Three experiments with rat subjects examined the effects on resurgence of the temporal distribution of reinforcement for the alternative behavior that is presented while the first response is being eliminated. Experiments 1 and 2 examined resurgence when rich rates of reinforcement at the onset of response elimination became leaner over sessions (i.e., forward thinning) and when lean rates became richer (i.e., reverse thinning). Both procedures weakened resurgence compared with that in a group that received the richest rate during all sessions. However, forward thinning was more effective than reverse thinning at reducing the resurgence effect. Experiment 3 found that final resurgence was eliminated when the alternative behavior was reinforced and extinguished in alternating response elimination sessions. The results are consistent with the hypothesis that reinforcer delivery during response elimination provides a contextual stimulus for the extinction of the original behavior; its removal during resurgence testing causes ABC renewal to occur. The results are less consistent with an alternative account that emphasizes the removal of response disruption caused by alternative reinforcement (Shahan & Sweeney, 2011). Other theoretical and applied implications are discussed. (PsycINFO Database Record
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PMID:Correction to Schepers and Bouton (2015). 2579 14