Increased thin-spine density in frontal cortex pyramidal neurons in a genetic rat model of schizophrenia-relevant features

The cellular mechanisms altered during brain wiring leading to cognitive disturbances in neurodevelopmental disorders remain unknown. We have previously reported altered cortical expression of neurodevelopmentally regulated synaptic markers in a genetic animal model of schizophrenia-relevant behavioral features, the Roman-High Avoidance rat strain (RHA-I). To further explore this phenotype, we looked at dendritic spines in cortical pyramidal neurons, as changes in spine density and morphology are one of the main processes taking place during adolescence. An HSV-viral vector carrying green fluorescent protein (GFP) was injected into the frontal cortex (FC) of a group of 11 RHA-I and 12 Roman-Low Avoidance (RLA-I) male rats. GFP labeled dendrites from pyramidal cells were 3D reconstructed and number and types of spines quantified. We observed an increased spine density in the RHA-I, corresponding to a larger fraction of immature thin spines, with no differences in stubby and mushroom spines. Glia cells, parvalbumin (PV) and somatostatin (SST) interneurons and surrounding perineuronal net (PNN) density are known to participate in FC and pyramidal neuron dendritic spine maturation. We determined by stereological-based quantification a significantly higher number of GFAP-positive astrocytes in the FC of the RHA-I strain, with no difference in microglia (Iba1-positive cells). The number of inhibitory PV, SST interneurons or PNN density, on the contrary, was unchanged. Results support our belief that the RHA-I strain presents a more immature FC, with some structural features like those observed during adolescence, adding construct validity to this strain as a genetic behavioral model of neurodevelopmental disorders.

ACTN3 R577X polymorphism related to sarcopenia and physical fitness in active older women

BACKGROUND

As the population is getting older, physical activity promotion becomes a good strategy to increase quality of life in the elderly; but genetic condition also plays an important role. The purpose of this study was to examine the association of the ACTN3 R577X polymorphism with physical fitness and muscle mass in physically active older women.

METHODS

A cross-sectional study was performed with two groups of older women who practiced physical exercise regularly. The first cohort comprised 164 women (age 69.7 ± 3.2 years) and the second cohort 131 women (age 78.5 ± 3.0 years). The main outcome measures were anthropometric measures with assessment of sarcopenia and sarcopenic obesity, self-reported physical activity EXERNET questionnaire (EEPAQ), evaluation of physical fitness (muscle strength and flexibility test), and ACTN3 genotyping.

RESULTS

Women above 75 years old with allele R presented a higher risk of experiencing sarcopenia compared to ACTNR XX homozygous women (odds ratio 0.356, 95% confidence interval 0.139-0.915, p = 0.026). Furthermore, statistically significant differences were found in the chair stand test (p = 0.04), as well as in the sit and reach test (p = 0.01), with better results for women below 75 years old with the ACTN3 XX genotype.

CONCLUSIONS

Sarcopenia and physical fitness show differences based on the ACTN3 R577X genotype in active older women.

ADHD medication and the inverted U-shaped curve: A pharmacological study in female mice performing the rodent Continuous Performance Test (rCPT)

BACKGROUND

The rodent Continuous Performance Test (rCPT) is an analogue of human CPTs where mice have to discriminate between target and non-target stimuli. The rCPT offers a readout of attentional performance and impulsive behaviour. This study aimed to determine if female C57BL/6 J mice could be trained in the rCPT since previously published rCPT studies have only used male mice and to study whether the effects of methylphenidate (MPH), atomoxetine (ATX), and dexamphetamine (AMPH) on attention and impulsivity depend on baseline (reference) levels of performance.

METHODS

48 female mice underwent rCPT training. Effects of MPH (1, 2, and 3 mg/kg), ATX (1, 3, and 5 mg/kg) and AMPH (0.3, 0.6, and 1 mg/kg) were assessed in a variable stimulus duration probe. Drugs were administered intraperitoneally and sequentially tested following a Latin-square design. Data were analysed using a repeated measurements mixed effect model and reference-dependent effects were studied.

RESULTS

ATX and AMPH improved performance as seen by increases in discriminability. These improvements were a result of a decreased false-alarm rate. AMPH showed a reference-dependent effect, improving the task performance of low-performing mice and decreasing the performance of high-performing mice. MPH also showed this reference-dependent effects, albeit to a lesser extent. ATX and AMPH decreased premature responses and increased response criterion, but no reference-dependent effects were observed for these parameters.

CONCLUSION

This study presents a novel method to analyse baseline-dependent effects. It shows that the rCPT can be successfully used in pharmacological studies in female mice and demonstrates that the effect of ADHD medication is in line with the inverted U-shape theory of performance-arousal relationship.

Dissociation between schizophrenia-relevant behavioral profiles and volumetric brain measures after long-lasting social isolation in Roman rats

Social isolation rearing of rodents is an environmental manipulation known to induce or potentiate psychotic-like symptoms and attentional and cognitive impairments relevant for schizophrenia. When subjected to a 28-week isolation rearing treatment, the Roman high-avoidance (RHA-I) rats display the common behavioral social isolation syndrome, with prepulse inhibition (PPI) deficits, hyperactivity, increased anxiety responses and learning/memory impairments when compared to their low-avoidance (RLA-I) counterparts. These results add face validity to the RHA-I rats as an animal model for schizophrenia-relevant behavioral and cognitive profiles and confirm previous results. The aim here was to further investigate the neuroanatomical effects of the isolation rearing, estimated through volume differences in medial prefrontal cortex (mPFC), dorsal striatum (dSt) and hippocampus (HPC). Results showed a global increase in volume in the mPFC in the isolated rats of both strains, as well as strain effects (RLA > RHA) in the three brain regions. These unexpected but robust results, might have unveiled some kind of compensatory mechanisms due to the particularly long-lasting isolation rearing period, much longer than those commonly used in the literature (which usually range from 4 to 12 weeks).

Evolution of Bacterial Global Modulators: Role of a Novel H-NS Paralogue in the Enteroaggregative Escherichia coli Strain 042

Bacterial genomes sometimes contain genes that code for homologues of global regulators, the function of which is unclear. In members of the family Enterobacteriaceae, cells express the global regulator H-NS and its paralogue StpA. In Escherichia coli, out of providing a molecular backup for H-NS, the role of StpA is poorly characterized. The enteroaggregative E. coli strain 042 carries, in addition to the hns and stpA genes, a third gene encoding an hns paralogue (hns2). We present in this paper information about its biological function. Transcriptomic analysis has shown that the H-NS2 protein targets a subset of the genes targeted by H-NS. Genes targeted by H-NS2 correspond mainly with horizontally transferred (HGT) genes and are also targeted by the Hha protein, a fine-tuner of H-NS activity. Compared with H-NS, H-NS2 expression levels are lower. In addition, H-NS2 expression exhibits specific features: it is sensitive to the growth temperature and to the nature of the culture medium. This novel H-NS paralogue is widespread within the Enterobacteriaceae. IMPORTANCE Global regulators such as H-NS play key relevant roles enabling bacterial cells to adapt to a changing environment. H-NS modulates both core and horizontally transferred (HGT) genes, but the mechanism by which H-NS can differentially regulate these genes remains to be elucidated. There are several instances of bacterial cells carrying genes that encode homologues of the global regulators. The question is what the roles of these proteins are. We noticed that the enteroaggregative E. coli strain 042 carries a new hitherto uncharacterized copy of the hns gene. We decided to investigate why this pathogenic E. coli strain requires an extra H-NS paralogue, termed H-NS2. In our work, we show that H-NS2 displays specific expression and regulatory properties. H-NS2 targets a subset of H-NS-specific genes and may help to differentially modulate core and HGT genes by the H-NS cellular pool.

Tetracycline alters gene expression in Salmonella strains that harbor the Tn10 transposon

In this report, we show that bacterial plasmids that harbor the Tn10 transposon (i.e., the IncHI1 plasmid R27) modify expression of different Salmonella regulons responding to the presence of tetracycline (Tc) in the medium. By using as a model the Tc-dependent upregulation of the ibpAB operon (which belongs to the heat shock regulon), we have identified Tn10-tetA (coding for a Tc efflux pump) and adjacent tetC sequences as required for ibpAB upregulation. Characterization of transcripts in the tetAC region showed that tetA transcription can continue into tetC sequences, generating a long 3'UTR sequence, which can protect transcripts from RNA processing, thus increasing the expression of TetA protein. In the presence of Tc, the DnaK and IbpA chaperones are overexpressed and translocated to the periplasm and to the membrane fraction respectively. DnaK targeting unfolded proteins is known to induce heat shock by avoiding RpoH proteolysis. We correlate expression levels of Tn10-encoded TetA protein with heat shock induction in Salmonella, likely because TetA activity compromises protein secretion.

Heart rate recovery is associated with obesity traits and related cardiometabolic risk factors in children and adolescents

BACKGROUND AND AIMS

Increased vagal activity is associated with obesity and metabolic risk in children and adolescents. The aim of the present cross-sectional study was to examine the association of parasympathetic function, as assessed by heart rate recovery (HRR) from a maximal exercise cycle-ergometer test, with obesity traits and related cardiometabolic risk factors in Spanish children and adolescents.

METHODS AND RESULTS

A sample of 437 Spanish 9-year-old-children and 235 15-year-old-adolescents participated in the study. The variables measured were anthropometric characteristics (height, body mass and waist circumference) and physical activity using the Actigraph accelerometer. Additional measured outcomes included fasting insulin, triglycerides, high-density lipoprotein cholesterol (HDLc) and blood pressure. A metabolic risk score was computed as the mean of the standardised outcomes scores. The HRR was calculated as the difference between peak heart rate and heart rate 1, 3 and 5 min after cessation of the maximal ergometer test. Diastolic blood pressure was associated with all the HRR parameters in 9-year-old-girls. In 9-year-old-boys, the 3-min HRR was inversely associated with systolic blood pressure (p < 0.05) and Homeostasis Model Assessment (HOMA) (p < 0.05). Five minute HRR was inversely associated with waist circumference (p < 0.05), sum of five skinfolds (p < 0.01) and HOMA (p = 0.004). There were no significant associations in adolescents. In 9-year-old-girls, the adjusted 5-min HRR showed significant differences between quartile 2 and 4 of metabolic risk (p = 0.011). In all samples, the adjusted HRR (1-, 3- and 5-min HRR) did not show significant differences across quartiles.

CONCLUSION

HRR was inversely associated with obesity traits and related cardiometabolic risk factors mainly in healthy boys.

Recommended levels of physical activity to avoid adiposity in Spanish children

What is already known about this subject There is an association between adiposity levels and physical activity guidelines for adolescents. Achieving physical activity recommendations helps adolescents to prevent obesity status. What this study adds This paper presents an association between physical activity levels and obesity status. This paper supports physical activity recommendations to avoid children's obesity levels. This paper emphasizes vigorous physical activity for this matter.

BACKGROUND

There is no information about physical activity (PA) recommendations to avoid children's obesity levels and how much of vigorous PA (VPA) is included into the '60 minutes of MVPA 5 days a week' recommendation for children.

OBJECTIVE

The aim of this study was to examine the association between PA and adiposity in children and to examine whether the current PA guidelines are associated with a low risk of having excess of body fat in children, with special focus on sex differences, and PA intensity.

METHODS

A sample of 439 Spanish children aged 8-10 years from the European Youth Heart Study participated in the study. The variables measured were anthropometric characteristics (height, weight, body mass index [BMI], skin-folds and waist circumference) and PA was measured during 6 consecutive days using the GT1M accelerometer.

RESULTS

Receiver operating characteristic analysis showed significant cut-off points associated with non-overweight: 45 min d(-1) of VPA and 67 min d(-1) of moderate-to-vigorous physical activity (MVPA) (using BMI categories); and non-fat: 41 min d(-1) of VPA and 67 min d(-1) of MVPA (using percentage of body fat) and 38 min d(-1) of VPA and 47 min d(-1) of MVPA (using waist circumference categories) for boys. For girls, the optimal cut-offs of moderate-to-vigorous activity and MVPA associated with non-overweight were 24 and 57 min d(-1) , respectively (BMI). Boys who did not meet 67 min in MVPA had an increased risk of being overweight + obese and overfat + obese (odds ratio [OR] = 2.48, 95% confidence interval [CI] = 1.36, 4.53, and OR = 2.56, 95% CI = 1.12, 5.82).

CONCLUSIONS

The findings support current PA recommendations (60 min d(-1) of MVPA) to avoid excess of body fat in Spanish children. However, VPA appears to be an important component for the prevention of obesity, and our findings suggest that PA recommendations should specify the dose of VPA required for optimal health. Therefore, public health PA recommendations should incorporate specifically a greater dose of VPA into the total amount of MVPA in 8- to 10-year-old boys.

Prevalence of overweight and obesity in non-institutionalized people aged 65 or over from Spain: the elderly EXERNET multi-centre study

Coupled with the growth of the older population, an increase in the prevalence of overweight and obesity in this age group has occurred in the last decades. The main aims of the present study were (i) to provide an updated prevalence of overweight and obesity in a representative sample of the Spanish elderly population; (ii) to calculate the prevalence of sarcopenic obesity (SO) and (iii) to analyse the relationships between adiposity measurements and lifestyle. A cross-sectional study was carried out in a sample of 3136 persons representative of the non-institutionalized population ≥65 years of age. Anthropometric measurements were obtained using standardized techniques and equipment. Overall, 84% of the population can be categorized as overweight and/or obese. The present study indicates that 67% of the Spanish elderly population has an increased percentage of fat mass and more than 56% suffer from central obesity. Moreover, SO is present in 15% of the Spanish elderly population. Finally, a strong relationship between both physically active and sedentary lifestyles and the level of adiposity was found. Prevalence of overweight and obesity among elderly people in Spain is very high and is still increasing. Lifestyle seems to be a determinant factor in the development of obesity among elderly people.

Patterns of physical activity in Spanish children: a descriptive pilot study

BACKGROUND

The majority of Spanish adults and children do not engage in enough physical activity to be beneficial for health. There is a need for objective and accurate assessment of the proportion of children meeting the physical activity recommendation for health. Assessing patterns of physical activity both between days (during weekdays and weekend days) and within days is of interest to improve our understanding of the variation in Spanish children's physical activity and to provide efficient intervention programmes.

METHODS

A sample of 221 children: 136 9-year-old children (68 boys and 68 girls) and 85 15-year-old children (36 girls and 49 boys) from 12 urban public schools in Madrid, Spain entered the study. The variables measured were anthropometric characteristics (height, weight, body mass index) and physical activity measured during four consecutive days using the GT1M accelerometer.

RESULTS

Younger children were more active and less sedentary than older ones during week and weekend days. Nine-year-old boys and girls achieved significantly (P < 0.05) more moderate to vigorous physical activity (MVPA) and significantly (P < 0.01) less sedentary time than older 15-year-old children. During weekdays more children achieved physical activity recommendations versus weekend days. Physical activity patterns analyses indicated that boys achieved relatively high values of MVPA from 1100 till 1300 h (school break) and from 1800 till 2000 h in comparison with the rest of the day. Girls were substantially different, with the 9-year-old girls having only two obvious peaks of weekday MVPA at lunch (1300) and after school (1900 h) while the adolescent girls had no clear peak of MVPA.

CONCLUSIONS

Few children achieved the level of MVPA recommended for health; at particular risk were adolescent girls. More effort needs to be devoted to promoting appropriate opportunities for Spanish girls across the day and to promoting physical activity during weekends for all children.

Changes in 5-HT2A-mediated behavior and 5-HT2A- and 5-HT1A receptor binding and expression in conditional brain-derived neurotrophic factor knock-out mice

Changes in brain-derived neurotrophic factor (BDNF) expression have been implicated in the etiology of psychiatric disorders. To investigate pathological mechanisms elicited by perturbed BDNF signaling, we examined mutant mice with central depletion of BDNF (BDNF(2L/2LCk-cre)). A severe impairment specific for the serotonin 2A receptor (5-HT(2A)R) in prefrontal cortex was described previously in these mice. This is of much interest, as 5-HT(2A)Rs have been linked to neuropsychiatric disorders and anxiety-related behavior. Here we further characterized the serotonin receptor alterations triggered by BDNF depletion. 5-HT(2A) ([(3)H]-MDL100907) and 5-HT(1A) ([(3)H]-WAY100635) receptor autoradiography revealed site-specific alterations in BDNF mutant mice. They exhibited lower 5-HT(2A) receptor binding in frontal cortex but increased binding in hippocampus. Additionally, 5-HT(1A) receptor binding was decreased in hippocampus of BDNF mutants, but unchanged in frontal cortex. Molecular analysis indicated corresponding changes in 5-HT(2A) and 5-HT(1A) mRNA expression but normal 5-HT(2C) content in these brain regions in BDNF(2L/2LCk-cre) mice. We investigated whether the reduction in frontal 5-HT(2A)R binding was reflected in reduced functional output in two 5-HT(2A)-receptor mediated behavioral tests, the head-twitch response (HTR) and the ear-scratch response (ESR). BDNF(2L/2LCk-cre) mutants treated with the 5-HT(2A) receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) showed a clearly diminished ESR but no differences in HTR compared to wildtypes. These findings illustrate the context-dependent effects of deficient BDNF signaling on the 5-HT receptor system and 5-HT(2A)-receptor functional output.

Prevalence of dementia in a southern European population in two different time periods: the ZARADEMP Project

OBJECTIVE

To compare the prevalence of dementia in two different time periods and two different studies.

METHOD

Representative, random samples of the elderly (>65 years) in the Zaragoza Study or ZARADEMP-0 (n = 1080) completed the previous decade, and now in Wave I of the ZARADEMP Project or ZARADEMP-I (n = 3715) were interviewed. Standardized measures included the Geriatric Mental State and the History and Aetiology schedule. Cases of dementia were diagnosed according to DSM-IV criteria.

RESULTS

Adjusted, global prevalence of dementia has not varied significantly: it was 5.2% (95% CI = 3.9-6.6) in ZARADEMP-0 and 3.9% (95% CI = 3.3-4.5) in ZARADEMP-I (prevalence ratio = 0.75; 95% CI = 0.56-1.02). However, the prevalence in ZARADEMP-I was significantly lower among men, particularly in all age groups between 70 and 84 years.

CONCLUSION

Stability of the global prevalence of dementia in the elderly population has been documented. However, the decreased prevalence found in elderly men stimulated environmental hypotheses.

Comparison of two low-calorie diets: a prospective study of effectiveness and safety

OBJECTIVE

To evaluate the cost-effectiveness and safety of two distinct low calorie diets (LCD).

DESIGN

Prospective controlled study.

METHODS

67 obese patients [body mass index (BMI) 40 kg/m2] were included in two study groups. Group A: 26 patients followed a 458 kcal diet given in three meals for 1 month. Group B: 41 patients followed a 800 kcal diet for 3 months and with outpatient control.

MEASUREMENTS

Anthropometric, cardiovascular risk and nutritional profile changes were evaluated, as well as total direct and indirect costs, and the incidence of complications.

RESULTS

No significant initial differences were observed between the two study groups. Eighty-six point two per cent of the patients completed the therapy correctly. After treatment a significant decrease was observed in the following variables for both groups, but no differences were detected between Groups A and B: mean weight loss (A= 9.28 kg, B= 8.7 kg), ponderal loss percentage (A/B= 7.2/6.8%), glycemia (A/B= 18.6/12.1 mg/dl), systolic blood pressure (SBP) (A/B= 11.8/6.5 mmHg), diastolic blood pressure (DBP) (A/B 5.9/6.8 mmHg), and final insulin-resistance (IR) index (A= 4.4, B= 4.3). Group A had the highest drop in total cholesterol (37.7 vs 8.1 mg/dl) and triglycerides (54.4 vs 2.5 mg/dl). No changes were observed in ureic acid, renal function and serum albumin. Thirty-six patients (55.3%) suffered trivial complications associated to the VLCD (16.9% gastrointestinal, 20% anxiety), with no differences between groups. Group A patients were on sick leave due to asthenia, and two patients in this group had serious complications (transient ischemic attack and atrial fibrillation). The total cost of Group A treatment was 3018.9 against 582.6 euros for Group B.

CONCLUSIONS

The 3-month 800 kcal/day VLCD was more cost-effective and safer than the 1-month 458 kcal/day diet.

Exacerbated loss of cell survival, neuropeptide Y-immunoreactive (IR) cells, and serotonin-IR fiber lengths in the dorsal hippocampus of the aged flinders sensitive line “depressed” rat: Implications for the pathophysiology of depression?

Impairment of hippocampal neurogenesis has been proposed to provide a cellular basis for the development of major depression. Studies have shown that serotonin (5-HT) and neuropeptide Y (NPY) may be involved in stimulating cell proliferation in the dentate gyrus. The Flinders-sensitive line (FSL) rat represents a genetic model of depression with characterized 5-HT and NPY abnormalities in the hippocampus. Consequently, it could be hypothesized that hippocampal neurogenesis in the FSL rat would be impaired. The present study examined the relationship among 1) number of BrdU-immunoreactive (IR) cells, 2) NPY-IR cells in the dentate gyrus, and 3) length of 5-HT-IR fibers in the dorsal hippocampus, as well as volume and number of 5-HT-IR cells in the dorsal raphé nucleus, in adult and aged FSL rats and control Flinders-resistant line (FRL) rats. Surprisingly, adult FSL rats had significantly more BrdU-IR and NPY-IR cells compared with adult FRL rats. However, aging caused an exacerbated loss of these cell types in the FSL strain compared with FRL. The aged FSL rats also had shortened 5-HT-IR fibers in the dorsal hippocampus, indicative of an impaired 5-HT innervation of this area, compared with FRL. These results suggest that, for "depressed" FSL rats, compared with FRL rats, aging is associated with an excacerbated loss of newly formed cells in addition to NPY-IR cells and 5-HT-IR dendrites in the hippocampus. These observations may be of relevance to the depression-like behavior of the FSL rat and, by inference, to the pathophysiology of depression.

[Prognostic morbidity and mortality factors in hospital enteral nutrition: prospective study]

OBJECTIVE

To determine the prognostic factors that may best for see the outcome of an enteral nutritional intervention and to assess the assistance quality of a nutrition unit.

SETTING AND SUBJECTS

Patients that required enteral nutrition during hospital admission at a third level center.

INTERVENTIONS

Observational prospective study in which 160 patients were included by means of consecutive sampling, for a 6-months follow-up period. Underlying pathology, disability degree, nutritional assessment, type of enteral nutrition, complications, nursing care, and clinical course of patients were determined.

RESULTS

severe caloric and protein hyponutrition was diagnosed in 48.4 and 52.9% of patients; stress degree was moderate in 52.2% and severe in 36.5%. In 88.2% of patients variation of protein parameters was unchanged or improved, with a 0.26 g/dL increase in albumin levels and 2.4 m/dL in prealbumin (p < 0.05). Multivariate analysis adjusted for plasma albumin at admission showed that besides this biochemical parameter, a severe stress degree, a decreased alertness level, and worsening of protein variation during admission are independent prognostic mortality factors during an enteral nutritional intervention in the hospitalized patient (p < 0.05).

CONCLUSIONS

alertness level, degree of caloric hyponutrition, stress degree, plasma albumin levels, and variation of protein parameters during nutritional support are independent prognostic factors for the nutritional intervention outcomes. The development of global monitoring systems of assistance activity and quality of Nutrition Units is paramount in order to improve the efficiency of enteral nutritional support at the hospital setting, to advance in patients care and promote the development of nutritional therapy.

Non-serotonergic dorsal and median raphe projection onto parvalbumin- and calbindin-containing neurons in hippocampus and septum

The median raphe nucleus is involved in controlling and maintaining hippocampal activity through its projection to inhibitory neurons in medial septum and hippocampus. It has been shown that anterogradely axonal-traced fibers originating in the median raphe nucleus project onto calbindin-containing neurons in hippocampus and parvalbumin-containing neurons in medial septum. Parallel immunohistochemistry studies showing serotonin fibers contacting calbindin- and parvalbumin-positive neurons have led to the assumption that raphe fibers projecting on these types of neurons are mainly serotonergic. However, in both dorsal and median raphe nucleus there is a large amount of non-serotonergic neurons which also are projecting neurons, indicating that a part of the raphe fibers projecting to hippocampus and septum may be non-serotonergic. Our aim was to determine whether there is a non-serotonergic projection from the raphe nucleus onto calbindin- and parvalbumin-containing neurons in hippocampus and septum. Biotin dextran amine was used as the anterograde neuronal tracer and injected into either dorsal or median raphe nucleus. By use of triple immunofluorescence-labeling we analyzed the serotonergic content of the biotin dextran amine-labeled fibers contacting parvalbumin- and calbindin-positive neurons. Surprisingly, we found a significant non-serotonergic projection from both dorsal and median raphe nuclei onto calbindin- and parvalbumin-containing interneurons in septum and hippocampus, with a preference in hippocampus for projecting onto calbindin-positive neurons. These results indicate that the raphe nuclei may exert their control on hippocampal and septal activity not only through a serotonergic projection, but also through a significant non-serotonergic pathway.

Impaired learning correlates with size of excitotoxic hippocampal CA3 lesions in adult rats, but shows no amelioration by CA3 transplants

Hippocampal CA3 pyramidal cells grafted as cell suspensions to excitotoxic hippocampal lesions in adult rats can exchange several types of short and long range nerve connections with the host brain. We now examined whether such grafts also had functional effects in terms of ameliorating lesion-induced learning and memory deficits. Adult, male rats with bilateral, one week old, ibotenic acid-lesions of the hippocampal CA3 region, were grafted with suspensions of fetal (E18-19) CA3 cells. Seven weeks later the animals were tested for spatial navigation in the Morris Watermaze, together with groups of lesion-only and sham-operated, control rats. The tests were performed over 5 days, with 4 trials per day. At the end of the trials, the size of the lesions and the size and structural incorporation of the transplants in the host brains were evaluated morphometrically for correlations with the behavioural data. We found significant differences in swim pathlength and latency to find the platform in the Morris Watermaze between the lesion-only group and the grafted group versus the sham operated group, but no significant difference between the lesion-only and the grafted group. There was a significant positive correlation between the size of the CA3 lesions and the paucity of performance of the rat in the Watermaze, just as spontaneous recovery accordingly had not occurred over the 8 weeks postlesion. We conclude that the behavioural improvement exerted by the CA3 cell suspension grafts, at a time point when graft-host connections have had time to establish, is at most incomplete by these transplants, pointing to the difficulties there may be in obtaining full functional integration.

Serotonin induces a decrease of 5-HT(1A) immunoreactivity in organotypic hippocampal cultures

Serotonin reuptake inhibitors used for the treatment of depression act by increasing serotonin levels at the synaptic cleft and thereby activating 5-HT(1A) serotonin receptors. However, the effect of increased levels of serotonin on postsynaptic 5-HT(1A) receptor density is unknown. The purpose of this study was to investigate, in a culture model, how postsynaptic 5-HT(1A) receptors are influenced by serotonin. Different concentrations of serotonin (0.5, 1, 10, 50 and 100 microM) were added to organotypic hippocampal cultures and incubated for 1 week. The cultures were immunostained for the 5-HT(1A) receptor and the staining analyzed densitometrically. 5-HT(1A) levels decreased with increasing serotonin concentrations, being significant at 10, 50 and 100 microM. These results indicate that at increasing serotonin levels the density of postsynaptic 5-HT(1A) receptors is down-regulated.

Simultaneous tyrosine and serine phosphorylation of STAT3 transcription factor is involved in Rho A GTPase oncogenic transformation

Stats (signal transducers and activators of transcription) are latent cytoplasmic transcription factors that on a specific stimulus migrate to the nucleus and exert their transcriptional activity. Here we report a novel signaling pathway whereby RhoA can efficiently modulate Stat3 transcriptional activity by inducing its simultaneous tyrosine and serine phosphorylation. Tyrosine phosphorylation is exerted via a member of the Src family of kinases (SrcFK) and JAK2, whereas the JNK pathway mediates serine phosphorylation. Furthermore, cooperation of both tyrosine as well as serine phosphorylation is necessary for full activation of Stat3. Induction of Stat3 activity depends on the effector domain of RhoA and correlates with induction of both Src Kinase-related and JNK activities. Activation of Stat3 has biological implications. Coexpression of an oncogenic version of RhoA along with the wild-type, nontransforming Stat3 gene, significantly enhances its oncogenic activity on human HEK cells, suggesting that Stat3 is an essential component of RhoA-mediated transformation. In keeping with this, dominant negative Stat3 mutants or inhibition of its tyrosine or serine phosphorylation completely abrogate RhoA oncogenic potential. Taken together, these results indicate that Stat3 is an important player in RhoA-mediated oncogenic transformation, which requires simultaneous phosphorylation at both tyrosine and serine residues by specific signaling events triggered by RhoA effectors.

Searching new targets for anticancer drug design: the families of Ras and Rho GTPases and their effectors

The Ras superfamily of low-molecular-weight GTPases are proteins that, in response to diverse stimuli, control key cellular processes such as cell growth and development, apoptosis, lipid metabolism, cytoarchitecture, membrane trafficking, and transcriptional regulation. More than 100 genes of this superfamily grouped in six subfamilies have been described so far, pointing to the complexities and specificities of their cellular functions. Dysregulation of members of at least two of these families (the Ras and the Rho families) is involved in the events that lead to the uncontrolled proliferation and invasiveness of human tumors. In recent years, the cloning and characterization of downstream effectors for Ras and Rho proteins have given crucial clues to the specific pathways that lead to aberrant cellular growth and ultimately to tumorigenesis. A direct link between the functions of some of these effectors with the appearance of transformed cells and their ability to proliferate and invade surrounding tissues has been made. Accordingly, drugs that specifically alter their functions display antineoplasic properties, and some of these drugs are already under clinical trials. In this review, we survey the progress made in understanding the underlying molecular connections between carcinogenesis and the specific cellular functions elicited by some of these effectors. We also discuss new drugs with antineoplastic or antimetastatic activity that are targeted to specific effectors for Ras or Rho proteins.

Factors associated with physical activity among Spanish youth through the National Health Survey

BACKGROUND

Physical inactivity is emerging as one of the largest public health problems throughout Europe. This study updates descriptive data on physical activity and the factors associated with it among the 6- to 15-year-old Spanish population during leisure time through the National Health Survey.

METHODS

This is a cross-sectional study from a representative sample of Spanish children's physical activity during their leisure time. Sample size was 1,358 children between the ages of 6 and 15 years. Univariate analyses were carried out first, and then significant variables were entered into a logistical regression nonconditional model.

RESULTS

Less than 30% of children were active and the percentage of active boys was higher than that of active girls in all age categories. From the age of 11 the percentage of total active children was stabilized. Children from the two highest social statuses (SS) were significantly more active than children from the lowest SS group. Children from large towns were more active than children from small towns. Active children reported eating more meat or fish than the less active ones.

CONCLUSIONS

The results suggest that characteristics of age, sex, town size, and social status should be considered when designing physical activity strategies for Spanish children.

Rho signals to cell growth and apoptosis

Ras and Rho GTPases are among the best studied signaling molecules in molecular biology. Essential cellular processes, such as cell growth, lipid metabolism, cytoarchitecture, membrane trafficking, transcriptional regulation, apoptosis, and response to genotoxic agents, are directly modulated by different members of this superfamily of proteins. Not until recently have we begun to understand the physiological implications of Ras and Rho GTPases, linking them to processes such as embryonic development, tissue remodeling, tumorigenesis and metastasis. In this sense, uncontrolled activation, due to overexpression of different members of the Rho family in a variety of tissues, leads to uncontrolled proliferation and invasiveness of human tumors. In this review, an attempt to briefly integrate recent findings in transcriptional regulation by Rho GTPases in the context of carcinogenesis and metastasis as well as apoptosis is made.

Apoptosis induced by Rac GTPase correlates with induction of FasL and ceramides production

Rho proteins, members of the Ras superfamily of GTPases, are critical elements in signal transduction pathways governing cell proliferation and cell death. Different members of the family of human Rho GTPases, including RhoA, RhoC, and Rac1, participate in the regulation of apoptosis in response to cytokines and serum deprivation in different cell systems. Here, we have characterized the mechanism of apoptosis induced by Rac1 in NIH 3T3 cells. It requires protein synthesis and caspase-3 activity, but it is independent of the release of cytochrome c from mitochondria. Moreover, an increase in mitochondria membrane potential and the production of reactive oxygen species was observed. Rac1-induced apoptosis was related to the simultaneous increase in ceramide production and synthesis of FasL. Generation of FasL may be mediated by transcriptional regulation involving both c-Jun amino terminal kinase as well as nuclear factor-kappa B-dependent signals. None of these signals, ceramides or FasL, was sufficient to induce apoptosis in the parental cell line, NIH 3T3 cells. However, any of them was sufficient to induce apoptosis in the Rac1-expressing cells. Finally, inhibition of FasL signaling drastically reduced apoptosis by Rac1. Thus, Rac1 seems to induce apoptosis by a complex mechanism involving the generation of ceramides and the de novo synthesis of FasL. These results suggest that apoptosis mediated by Rac1 results from a signaling mechanism that involves biochemical and transcriptional events under control of Rac1.

[Revalidation and standardization of the cognition mini-exam (first Spanish version of the Mini-Mental Status Examination) in the general geriatric population]

BACKGROUND

The revalidation of the Mini Examen Cognoscitivo (MEC), first Spanish version (1978) of the Mini-Mental Status Examination (MMSE) and documentation of "population-based norms" should clarify the potential confusion induced by later versions of MMSE.

METHODS

CONTEXT

The Zaragoza Study on the prevalence of dementia and depression in a representative sample of the elderly community (N = 1,080).

INSTRUMENTS

MEC-35 and MEC-30 points, and validated, Spanish versions of Geriatric Mental State (GMS), History and Aetiology Schedule (HAS) and Social Status Schedule (SSS).

PROCEDURE

a) validation of MEC (standardized lay interviewers) against the gold standard of psychiatric diagnosis (DSM-III-R), two months later; b) "population-based norms" in the "healthy" population, and c) comparison with other MMSE versions.

RESULTS

The instrument fulfills criteria of "feasibility", "content", "procedural" and "construct validity". Test-retest reliability: weighted kappa = 0.637. MEC-30 (cut-off point 23/24), sensitivity = 89.8%, specificity = 75.1% (80.8% with the cut-off at 22/23), and ROC curve, AUC = 0.920. The coefficients of individual items were satisfactory and the specificity increases in MEC-35 (83.9%). Other MMSE Spanish versions have not improved these coefficients. "Population-based norms" confirm the hypothesized influence of age and education level. MEC-30 is the version with most comparable results with the MMSE in USA.

CONCLUSIONS

The validity of MEC is confirmed in the elderly population, with the same cut-off points recommended in the original standardization. MEC-30 is the best version for international comparisons.

Connective integration of hippocampal grafts in excitotoxic hippocampal lesions in adult rats: an anterograde axonal tracing study

Exchange of nerve connections between developing neural grafts and adult recipient brains is enhanced for grafts placed in excitotoxic lesions, which spare recipient brain afferent axons in otherwise neuron-depleted lesion areas. In previous studies of hippocampal grafts placed in such lesions, we have used anterograde axonal degeneration, histochemical Timm staining and acetylcholinesterase to demonstrate host-graft interconnectivity. In this study, we have now used three anterograde axonal tracers, Phaseoulus vulgaris-leukoaglutinin (PHA-L), biocytin and biotinylated dextran amine (BDA), which allow individual fibers to be traced. Adult male rats with 1-week-old axon-sparing ibotenic acid lesions of the dorsal CA3 region or fascia dentata were grafted into the respective lesions with suspensions of fetal (El8-19) CA3 cells or a block of neonatal fascia dentata tissue. One to twelve months later, recipients were injected with Phaseoulus vulgaris-leukoaglutinin or biocytin in the hippocampus contralateral to the graft to trace the possible ingrowth and distribution within the transplants of host commissural axons, or into the transplants with biotinylated dextran amine in order to trace outgrowing graft fibers. In rats with succesfull host Phaseoulus vulgaris-leukoaglutinin or biocytin injections, the CA3 and fascia dentata transplants were innervated by labelled host commissural fibers. In the dentate transplants, most commissural fibers projected as normally to the inner part of the molecular layer, with fewer aberrant fibers extending more superficially into the molecular layer. Following injections into the fascia dentata and CA3 grafts of biotinylated dextran amine, labelled graft fibers were traced into the ipsilateral host dentate hilus, CA3 and CA1. From some CA3 containing grafts, a few labelled fibers were also observed passing through the host fimbria-fornix to the lateral septum on the grafted side. A few fibers were projected as far as to the most septal levels of the contralateral CA1.

c-JUN, KROX-24, and c-FOS expression in hippocampal grafts placed in excitotoxic hippocampal lesions of the rat

Hippocampal transplants were examined for the expression of three specific immediate early gene encoded proteins in order to establish if grafted immature tissue maintains the basic molecular program necessary for gene transcription after grafting to excitotoxic (ibotenic acid-induced) lesions in adult host rat brains. The transplants were derived from newborn donor rats and were analyzed immunocytochemically for the presence of c-JUN, KROX-24, and c-FOS transcription factors 5 months after grafting. The expression and distribution patterns of these genes in the host hippocampus were identical to those in hippocampal neurons of normal untreated animals. c-JUN-, KROX-24-, and c-FOS-labeled neurons were also present in the transplants, where KROX-24 and c-FOS exhibited a distribution similar to host hippocampus. In contrast, c-JUN was more extensively expressed in the transplants, suggesting a molecular response to the grafting conditions and the actual graft-host brain interactions.

Transient forebrain ischemia-induced neuronal degeneration in fascia dentata transplants

Fascia dentata tissue blocks from newborn rats were grafted into one-week-old, ibotenic acid-induced lesions of the fascia dentata, or the normal fascia dentata of adult rats. After at least 2 months survival the recipient rats were subjected to 10 min of forebrain ischemia (4-vessel occlusion), and examined 2 or 4 days later for neuronal degeneration in the host hippocampi and the transplants, by silver staining and immunohistochemistry. Transplants survived well in both normal and lesioned host brains, with easily recognizable subfields and layers and presence of normal types of principal and non-principal neurons. As expected, argyrophilic, degenerating neurons were present in the pyramidal cell layer of CAl and CA3c of the non-grafted contralateral host hippocampus and in the contralateral dentate hilus (CA4). In the hilus the degeneration corresponded to the loss of somatostatin-immunoreactive neurons, while parvalbumin-immunoreactive neurons were spared. In the dentate transplants degenerating neurons were observed in the granule cell layer, the hilus and the adjacent CA3 pyramidal cell layer. There was no obvious loss of either somatostatin- or parvalbumin-immunoreactive neurons. The degeneration varied considerably between transplants, from a few to large groups of silver stained neurons, but this difference did not display any obvious relation to grafting into normal or lesioned hosts, the exact location of the grafts or the general organization and distribution of intrinsic or extrinsic host afferents in the grafts. The results demonstrate that both ischemia-susceptible and -resistant types of neurons grafted to normal and lesioned adult rat brains are susceptible to transient forebrain ischemia after transplantation. In spite of an extensive reorganization of transplant nerve connections, the physiologicalbiochemical mechanisms necessary for the induction of ischemic cell death were accordingly present in the transplants.