Understanding the molecular basis of the high oxygen affinity variant human hemoglobin Coimbra.

Human hemoglobin (Hb) Coimbra (ßAsp99Glu) is one of the seven ßAsp99 Hb variants described to date. All ßAsp99 substitutions result in increased affinity for O2 and decreased heme-heme cooperativity and their carriers are clinically characterized by erythrocytocis, caused by tissue hypoxia. Since ßAsp99 plays an important role in the allosteric α1ß2 interface and the mutation in Hb Coimbra only represents the insertion of a CH2 group in this interface, the present study of Hb Coimbra is important for a better understanding of the global impact of small modifications in this allosteric interface. We carried out functional, kinetic and dynamic characterization of this hemoglobin, focusing on the interpretation of these results in the context of a growth of the position 99 side chain length in the α1ß2 interface. Oxygen affinity was evaluated by measuring p50 values in distinct pHs (Bohr effect), and the heme-heme cooperativity was analyzed by determining the Hill coefficient (n), in addition to the effect of the allosteric effectors inositol hexaphosphate (IHP) and 2,3-bisphosphoglyceric acid (2,3-BPG). Computer simulations revealed a stabilization of the R state in the Coimbra variant with respect to the wild type, and consistently, the T-to-R quaternary transition was observed on the nanosecond time scale of classical molecular dynamics simulations.

Standard form of the Boston Naming Test: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Boston Naming Test (BNT) across 10 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,779 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the BNT as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained between 3-32% of the variance in BNT scores. Although t-tests showed significant differences between men and women for Mexico, Argentina, Chile, Cuba, Guatemala, and Bolivia on the BNT, none of the six countries had an effect size larger than 0.3. As a result, gender-adjusted norms were not generated. CONCLUSIONS: This is the first normative multicenter study conducted in Latin America to generate norms for the BNT; this study will have substantial repercussions for the practice of neuropsychology throughout the global region.

Modified Wisconsin Card Sorting Test (M-WCST): Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Modified Card Sorting Test (M-WCST) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico. Each subject was administered the M-WCST as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained between 2-33% of the variance in M-WCST scores. Although t-tests showed significant differences between men and women from seven different countries on the M-WCST, the effect sizes were small. As a result, gender-adjusted norms were not generated. CONCLUSIONS: This is the first normative multicenter study conducted in in Latin America aiming to create norms for the M-WCST; this study will have important implications for the future of neuropsychology in the region.

Hopkins Verbal Learning Test- Revised: Normative data for the Latin American Spanish speaking adult population.

OBJECTIVE: To generate normative data on the Hopkins Verbal Learning Test- Revised (HVLT-R) across 11 countries in Latin America, with country-specific adjustments for gender, age, and education, where appropriate. METHOD: The sample consisted of 3,977 healthy adults who were recruited from Argentina, Bolivia, Chile, Cuba, El Salvador, Guatemala, Honduras, Mexico, Paraguay, Peru, and, Puerto Rico. Each subject was administered the HVLT-R as part of a larger neuropsychological battery. A standardized five-step statistical procedure was used to generate the norms. RESULTS: The final multiple linear regression models explained 17- 45% of the variance in HVLT-R scores. Although t-tests showed significant differences between men and women in Guatemala on the HVLT-R, it was a small effect size. As a result, gender-adjusted norms were not generated. CONCLUSIONS: The results from this study will have a substantial impact on the practice of neuropsychology in Latin America, as this is the first normative multicenter study to develop norms for the HVLT-R in this region.

[Implementation of an indirect method for the measurement of memory in the elderly]. / Implementación de un método indirecto para medir la memoria en la tercera edad.

INTRODUCTION: There is interference between emotional factors and intellectual output in the elderly, in whom there is a high prevalence of depression. Low output in conventional psychological tests may lead to false positive diagnoses of dementia. PATIENTS AND METHODS: We evaluated 48 patients aged between 50 and 84 years with regard to their emotional and intellectual state by means of the SCAN system. We also used a test designed by ourselves to implicitly examine memory. This consisted of a task involving naming objects. Six stimuli were repeated three times, seeking an effect of perceptual representation of 'priming' which facilitated later recall. RESULTS: The results showed that patients with dementia recalled 0 to 2 of the repeated stimuli, as a result of weakened priming. Meanwhile the non-demented persons, in spite of having other neurological disorders answered between 4 and 6 times. Multivariate analysis of the variance showed that measurement of memory, both implicit and explicit, allowed discrimination between patients with and without dementia. However, the explicit results were not independent of the effects of depression. CONCLUSIONS: Implicit measurements of memory were superior to direct or explicit measurements in the diagnosis of dementia. Patients with other degenerative conditions, such as Parkinsonism and multisystemic atrophy, had above average results. This corroborates the view that the neurological basis of this type of memory is not at subcortical level.

Rearrangement of the dendritic morphology in limbic regions and altered exploratory behavior in a rat model of autism spectrum disorder.

Valproic acid (VPA) is a blocker of histone deacetylase widely used to treat epilepsy, bipolar disorders, and migraine; its administration during pregnancy increases the risk of autism spectrum disorder (ASD) in the child. Thus, prenatal VPA exposure has emerged as a rodent model of ASD. In the present study, we aimed to investigate the effect of prenatal administration of VPA (500mg/kg) at E12.5 on the exploratory behavior and locomotor activity in a novel environment, as well as on neuronal morphological rearrangement in the prefrontal cortex (PFC), in the hippocampus, in the nucleus accumbens (NAcc), and in the basolateral amygdala (BLA) at three different ages: immediately after weaning (postnatal day 21 [PD21]), prepubertal (PD35) and postpubertal (PD70) ages. Hyper-locomotion was observed in a novel environment in VPA animals at PD21 and PD70. Interestingly, exploratory behavior assessed by the hole board test at PD70 showed a reduced frequency but an increase in the duration of head-dippings in VPA-animals compared to vehicle-treated animals. In addition, the latency to the first head-dip was longer in prenatal VPA-treated animals at PD70. Quantitative morphological analysis of dendritic spine density revealed a reduced number of spines at PD70 in the PFC, dorsal hippocampus and BLA, with an increase in the dendritic spine density in NAcc and ventral hippocampus, in prenatal VPA-treated rats. In addition, at PD70 increases in neuronal arborization were observed in the NAcc, layer 3 of the PFC, and BLA, with retracted neuronal arborization in the ventral and dorsal hippocampus. Our results extend the list of altered behaviors (exploratory behavior) detected in this model of ASD, and indicate that the VPA behavioral phenotype is accompanied by previously undescribed morphological rearrangement in limbic regions.

[Utility of ligamentoplasty for the prevention of adjacent segment disease above 360 degree arthrodesis in degenerative lumbar spondylosis. Preliminary report]. / Utilidad de la ligamentoplastía para la prevención de la artrodesis en espondilolistesis lumbar degenerativa. Reporte preliminar.

BACKGROUND: Ligamentoplasty is a dynamic stabilization method used to treat lumbar stenosis and resect lumbar herniated discs with good results. The objective of this paper is to report preliminary results of the utility of ligamentoplasty to prevent adjacent segment disease above the arthrodesis. MATERIAL AND METHODS: Two groups of patients with degenerative lumbar spondylolisthesis who underwent circumferential arthrodesis. In 23 patients a dynamic stabilization system was placed in the segment above (group L), while this system was not used in 35 patients (group S). Degeneration and disease of the segment above were assessed. The statistical analysis was done with the SPSS 15.0 software. RESULTS: At the one-year follow-up, the incidence rate of adjacent segment degeneration was 11% for group L and 0% for group S; at the two-year follow-up it was 13% in both groups; at three years, 0% for group L and 19% for group S; at four years, 25% for group L and 0% for group S. At five years, 50% for group L and 0% for group S. Clinically significant radiculopathy occurred in two patients five years after surgery, one of whom also had adjacent segment disease. CONCLUSIONS: Based on the follow-up, at this moment it is not possible to show the utility of dynamic stabilization through ligamentoplasty to avoid adjacent segment disease above the arthrodesis.

[Comparison of three types of lumbar total disc arthroplasty. Four-year minimum follow-up]. / Comparación entre tres tipos de artroplastía total de disco lumbar. Seguimiento mínimo de 4 años.

BACKGROUND: Total lumbar disc replacement was developed to avoid the drawbacks of arthrodesis. This procedure should be done cautiously due to the various already known complications. The purpose of this study is to assess the clinical and radiographic results after single-level lumbar arthroplasty with the Prodisc-L, Maverick and Charité prostheses at our service. MATERIAL AND METHODS: A retrospective study was performed comparing the clinical and radiographic results of three groups of patients who underwent total lumbar disc arthroplasty from January 2000 to December 2007. RESULTS: Twenty-one lumbar prosthetic surgeries were performed. The Prodisc device was used in 13 patients, the Maverick in 4, and the Charité in 4. After the application of the Stauffer-Coventry scale, 16 patients reported excellent results and 5 good results. The mean preoperative interbody height was 7.9 mm and the mean postoperative height was 12.91 mm. The mean differential angle in the dynamic films was 5.47 degrees preoperatively and 4.61 postoperatively; the mean angle in neutral position was 13.38 preoperatively and 19.61 postoperatively. CONCLUSIONS: This study showed that the clinical result was good in all three groups. Mobility was better maintained with the Charité prosthesis compared to the Prodisc and Maverick devices. The three prostheses are appropriate for the treatment of lumbar degenerative disc disease.

Brain potentials reflect residual face processing in a case of prosopagnosia.

Here, ERPs were employed to characterise the residual face processing of FE, a patient with extensive damage to the ventral temporal-occipital cortex and a dense prosopagnosia. Alarge N170 was present in FE and he performed well in tests of face structural processing. Covert recognition of the faces of personal acquaintances was demonstrated with P300 oddball experiments. The onset latency of the P300 effect was normal, indicating fast availability of covert memory. The scalp topography of this component in FE was different from that of the P3b, presenting a centro-frontal maximum. FE also presented larger skin conductance responses to familiar than to unfamiliar faces. The amplitudes of both the single-trial P300s and the SCRs triggered by familiar faces were positively correlated with the degree of person-familiarity that FE had for the poser. He performed at chance when asked to select between the face of a familiar person and that of an unfamiliar person on the basis of explicit recognition, whereas he selected more the previously known face if the forced choice was based on trustworthiness or a vague sense of familiarity. The results suggest that in FE, early face processing was relatively intact and covert recognition was fast. Neural structures involved in the processing of emotional or social cues possibly mediate the covert recognition present in FE.

[Predictive factors for hospital infections caused by Gram-positive and Gram-negative organisms]. / Factores predictivos de las infecciones nosocomiales producidas por microorganismos grampositivos y gramnegativos.

BACKGROUND: Knowing the bacterian map and clinical profile of nosocomial infections (NI) in Spain may aid the better planning of empiric antimicrobian treatment. METHODS: A prospective incidence study carried out over 9 months was performed. Data collection out with the use of an EPINE project file. The chi square test and comparison of independent sample percentages were used for statistical analysis. RESULTS: During the study period 156 cases of NI (rate (5.5%) were detected: 65 patients with gram-negative bacilli infection (GNB), 34 by gram-positive cocci (GPC), 20 with mixed infection and 13 by Candida. The most frequent localization was urinary infection (63%) followed by surgical wound infection, pressure ulcers and respiratory infection. Of the 203 isolations, 57% corresponded to GNB, with E. coli being the most frequent microorganism. Staphylococcus aureus was the GPC most often found (95% methycilline sensitive). CONCLUSIONS: The profile of a patient with nosocomial infection in a hospital such as that in which the autors work would be as follows: if the patient were admitted in the department of internal medicine, was dementia or coma, denutrition, urinary catheter or neurologic disease and has NI (overall urinary infection) the infection would most likely be a caused by a gram-negative microorganism. If the patient has an i.v. line or is in a surgical ward, or has deep surgical wound infection the microorganism isolated would most likely be gram-positive.