Long-Term Memory Deficits in Schizophrenia: Primary or Secondary Dysfunction?

Long-term memory impairment is often found in schizophrenia. The question remains whether this is caused by other cognitive deficits. One hundred eighteen first-episode patients were compared with 45 control participants on several memory tasks. The role of processing speed and central executive functions on memory performance was examined with regression analysis for all participants and for patients separately. Deficits were found in general verbal learning performance and retrieval in episodic memory and semantic memory. Processing speed reduced disease-related variance in all memory variables. Coordination, organization of information, and speed of processing were the best predictors for long-term memory deficits in patients. The amount of explained variance, however, is small, especially in general verbal learning performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Laparoscopic vs conventional appendectomy--a meta-analysis of randomised controlled trials

A comparison was made of the dynamics of sympathoadrenal activity in 11 age-matched male and female rats, under basal conditions and after exposure to footshock. Rats were prepared with indwelling catheters in the tail artery 24 h before the experiment. Measurements were made of plasma corticosterone (COR), norepinephrine (NE), epinephrine (EPI), dihydroxyphenylalanine (DOPA), dihydroxyphenylglycol (DHPG) and dihydroxyphenylacetic acid (DOPAC) under resting conditions, after transfer to the shock box (novelty) and at various times after footshock. Under basal conditions, males have significantly higher blood pressure and plasma DHPG/NE ratios but lower plasma levels of COR, NE and DOPAC than females. Three min after exposure to the shock chamber (novelty stress) there were significant increases in COR, EPI, NE and DHPG in both sexes, while DOPA increased only in females and DOPAC remained unchanged in both sexes. Footshock produced a further increase in EPI, NE and DOPAC within 2 min, which lasted about 15 min. There were significant sex differences in the extent and duration of the response of COR, EPI and DHPG. The data show that the female sympathoadrenal system is more reactive than that of the male to the stresses of a novel environment and footshock. The smaller DHPG/NE ratios in females at rest and after stress suggest that neuronal uptake of NE is lower in females than in males. The finding that stress produces larger increments of plasma DOPA and DOPAC in female rats indicates that tyrosine hydroxylase in the sympathetic nerve terminals and adrenal medulla may also be higher than in males.     

A GAUSSIAN-1 Type Ab Initio MO Study of the [CH2NO]+ Potential Energy Surface. Theoretical Support for the Existence of Three Experimentally Distinguishable Isomers in the Gas Phase

The potential energy surface (PES) of [CH₂NO]⁺ ions with an NCO connectivity has been explored by GAUSSIAN-1 type calculations. Six isomers having an NCO backbone are found and characterized as minima on the PES; three of them are separated by isomerization barriers reasonably large enough to allow an experimental verification. The favored protonation site of neutral isocyanic acid (HNCO) is the nitrogen atom (proton affinity, calculated = 171.4 kcal/mol; experimental = 173 ± 1 kcal/mol) leading to the most stable isomer H₂NCO⁺ ( 1 ). For the protonation of NCOH at the nitrogen atom we predict a proton affinity for the cyanic acid of 179.7 kcal/mol. The resulting ion HNCOH⁺ ( 2 ) is 15.9 kcal/mol higher in energy than 1. The third stable isomer 5 having the NCO connectivity can be formally viewed as a complex between CN and the water radical cation; 5 is 72.9 kcal/mol less stable than H₂NCO⁺ ( 1 ). In addition, two high-energy isomers HN-C(H)O⁺(3) and HO-C(H)N⁺ ( 4 ) have been found, but according to the shape of the PES, they are predicted not to be accessible experimentally. The calculated thermochemical data are in excelled agreement with experimentally available values. The calculations are extended to the unimolecular fragmentation channels, which should be observed in mass-spectrometric experiments. The analysis of the results suggests that the hydrogen-atom elimination process is favored over all other dissociation channels, followed by loss of NH_2-· and NH.     

Cerebellar hypometabolism in focal epilepsy is related to age of onset and drug intoxication

BACKGROUND: The pathogenesis of transplantation-associated accelerated atherosclerosis is poorly understood, but it is likely to be an alloimmune response involving infiltration of the vessel wall by T lymphocytes and monocytes leading to smooth muscle cell proliferation and extracellular matrix deposition. RANTES is a chemokine that selectively chemoattracts T lymphocytes, NK cells, monocytes, and eosinophils. The expression of RANTES in accelerated atherosclerosis was investigated by in situ hybridization and immunohistochemistry. METHODS: Coronary arteries from six patients undergoing accelerated atherosclerosis were obtained at the time of retransplantation. Normal coronary arteries from two patients with idiopathic dilated cardiomyopathy were used as controls. Messenger RNA for RANTES was localized with digoxigenin-labeled complementary DNA probes. RANTES protein was detected by use of a monoclonal antibody and a three-step horseradish peroxidase method. RESULTS: RANTES mRNA and protein were detected in the lymphocytes, macrophages, myofibroblasts, and endothelial cells of arteries undergoing accelerated atherosclerosis but not in normal coronary arteries. CONCLUSIONS: In view of its in vitro biologic activity and in vivo expression pattern, RANTES may be a pivotal mediator of the cellular infiltrate seen in graft atherosclerosis. This information may help in the design of novel diagnostic and therapeutic approaches to this increasingly important disease process.     

A general probability estimation approach for neural comp

We describe an analytical framework for the adaptations of neural systems that adapt its internal structure on the basis of subjective probabilities constructed by computation of randomly received input signals. A principled approach is provided with the key property that it defines a probability density model that allows studying the convergence of the adaptation process. In particular, the derived algorithm can be applied for approximation problems such as the estimation of probability densities or the recognition of regression functions. These approximation algorithms can be easily extended to higher-dimensional cases. Certain neural network models can be derived from our approach (e.g., topological feature maps and associative networks).     

Semiological seizure classification

We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.