Personality traits, cognition and volumetric MRI changes in elderly patients with early-onset depression: A 2-year follow-up study.

Previous studies revealed personality changes in elderly patients with early-onset depression (EOD) that persist in euthymic stages. However, depression in older patients is a complex disorder that may affect not only personality, but also cognition and brain structure. To address this issue, a cross-sectional comparison and 2-year follow-up of 28 EOD elderly patients and 48 healthy controls included detailed neurocognitive assessment, estimates of brain volumes in limbic areas and white matter hyperintensities, as well as evaluation of the Five Factor Model of personality, in a remitted mood state. Results revealed that cognitive performances as well as brain volumes were preserved in EOD patients both at baseline and at follow-up. The increased Neuroticism factor and Anxiety facet scores as well as the decreased Warmth and Positive Emotions facet scores found at baseline reached the level of healthy controls after 2years. Only the Depression facet scores remained significantly higher in EOD patients compared to controls upon follow-up. Results were independent of depressive relapse since baseline (25% of patients). These findings suggest that both cognitive performances and brain volumes show long-term preservation in older EOD patients. In contrast, the depression-related personality facet might be a trait like marker that persists in the long-term evolution of this disorder.

Assessment of microbial community structure changes by amplified ribosomal DNA restriction analysis (ARDRA)

Amplified ribosomal DNA restriction analysis (ARDRA) is a simple method based on restriction endonuclease digestion of the amplified bacterial 16S rDNA. In this study we have evaluated the suitability of this method to detect differences in activated sludge bacterial communities fed on domestic or industrial wastewater, and subject to different operational conditions. The ability of ARDRA to detect these differences has been tested in modified Ludzack-Ettinger (MLE) configurations. Samples from three activated sludge wastewater treatment plants (WWTPs) with the MLE configuration were collected for both oxic and anoxic reactors, and ARDRA patterns using double enzyme digestions AluI+MspI were obtained. A matrix of Dice similarity coefficients was calculated and used to compare these restriction patterns. Differences in the community structure due to influent characteristics and temperature could be observed, but not between the oxic and anoxic reactors of each of the three MLE configurations. Other possible applications of ARDRA for detecting and monitoring changes in activated sludge systems are also discussed

Transcript profiling suggests that differential metabolic adaptation of mice to a high fat diet is associated with changes in liver to muscle lipid fluxes.

Genetically homogenous C57Bl/6 mice display differential metabolic adaptation when fed a high fat diet for 9 months. Most become obese and diabetic, but a significant fraction remains lean and diabetic or lean and non-diabetic. Here, we performed microarray analysis of "metabolic" transcripts expressed in liver and hindlimb muscles to evaluate: (i) whether expressed transcript patterns could indicate changes in metabolic pathways associated with the different phenotypes, (ii) how these changes differed from the early metabolic adaptation to short term high fat feeding, and (iii) whether gene classifiers could be established that were characteristic of each metabolic phenotype. Our data indicate that obesity/diabetes was associated with preserved hepatic lipogenic gene expression and increased plasma levels of very low density lipoprotein and, in muscle, with an increase in lipoprotein lipase gene expression. This suggests increased muscle fatty acid uptake, which may favor insulin resistance. In contrast, the lean mice showed a strong reduction in the expression of hepatic lipogenic genes, in particular of Scd-1, a gene linked to sensitivity to diet-induced obesity; the lean and non-diabetic mice presented an additional increased expression of eNos in liver. After 1 week of high fat feeding the liver gene expression pattern was distinct from that seen at 9 months in any of the three mouse groups, thus indicating progressive establishment of the different phenotypes. Strikingly, development of the obese phenotype involved re-expression of Scd-1 and other lipogenic genes. Finally, gene classifiers could be established that were characteristic of each metabolic phenotype. Together, these data suggest that epigenetic mechanisms influence gene expression patterns and metabolic fates.

Changes of beta-amyloid precursor protein splice patterns in brain cell aggregate cultures.

The splice pattern of beta-amyloid precursor protein (beta-APP) has been studied in a variety of neuronal and glial cells and in brain cell aggregate cultures by the polymerase chain reaction (PCR). The brain-typical pattern, in which beta-APP695 is the dominant form, has been found only in aggregate cultures but not in any of the other cell types including neuronal cell lines. Selective elimination of glial cells from aggregates resulted in increased quantities of beta-APP695, whereas removal of neurons led to a reduction of beta-APP695 and to an elevation of beta-APP751 and beta-APP770. This shift of splice pattern was not observed in cocultures of the neuronal cell line PC 12 with primary astrocytes combined in a variety of cellular ratios. Blood serum, which is an essential component of these cultures, tested on aggregates, did not reduce the amount of beta-APP695 or have any marked effects on splice patterns generally. From these results it is concluded that investigations on brain-typical splicing of beta-APP require primary neurons. Neuronal cell lines may be no suitable model systems. Splicing events favoring production of beta-APP695 may mark an important, very early step of amyloid formation in the brain.

Changes in understorey biomass and species composition after water level drawdown on pine mires in southern Finland

Tiivistelmä: Vedenpinnan alenemisen vaikutus sararämeen pintakasvillisuuden biomassaan ja lajistoon

Chemical changes in argisols under irrigated grape production in the central São Francisco river valley, Brazil

This study compares the chemical composition of the solution and exchange complex of soil in a 3-year-old irrigated vineyard (Vitis vinifera L., Red Globe cultivar) with that of adjacent clearing in the native hyperxerophyllic 'caatinga' vegetation. The soils are classified as Plinthic Eutrophic Red-Yellow Argisol; according to Soil Taxonomy they are isohyperthermic Plinthustalfs. Detailed physiographic characterization revealed an impermeable gravel and cobble covering the crystalline rocks; the relief of this layer was more undulating than the level surface. Significant higher concentrations of extractable Na, K, Mg and Ca were observed within the vineyard. Lower soil acidity, higher Ca/Mg ratios, as well as lower sodium adsorption and Na/K ratios reflected additions of dolomitic lime, superphosphate and K-bearing fertilizers. As the water of the São Francisco River is of good quality for irrigation (C1S1), the increases in Na were primarily attributed to capillary rise from the saline groundwater table. None of the soil in the study area was found to be sodic. About 62% of the vineyard had an Ap horizon with salinity levels above 1.5dSm-1 (considered detrimental for grape production); according to average values for this horizon, a potential 13% reduction in grape production was predicted. Differences in chemical composition in function of distance to the collector canals were observed in the clearing, but not in the vineyard. The influence of differences in the elevations of the surface and impermeable layers, as well as pediment thickness, was generally weaker under irrigation. Under irrigation, soil moisture was greater in points of convergent surface waterflow; the effect of surface curvature on chemical properties, though less consistent, was also stronger in the vineyard.

A phylogenetic study of the phosphoenolpyruvate carboxylase multigene family in Poaceae: understanding the molecular changes linked to C4 photosynthesis evolution

Phylogenetic reconstructions have supported several independent appearances of C₄ photosynthesis within grasses (Poaceae). These recurrent appearances appear to contradict the large number of biochemical and morphological changes required to change from C₃ to C₄, a paradox that leads to questions about the genetic changes underlying C₄ evolution. In this study, we analysed sequences encoding phosphoenolpyruvate carboxylases (PEPCs) in grasses in order to gain insights into the origin of the ppc-C₄ gene, which encodes a key enzyme in the C₄ pathway. We screened databanks for PEPC genes or cDNAs in grasses. A coding sequence of 1130 base pairs was used to build phylogenetic trees that supported the existence of four distinct PEPC gene lineages. Ppc-C₄ present in all C₄ grasses was also found in two C₃ species. The ppc-C₄ clade was congruent with the species tree, suggesting orthologous evolution. This result would imply that ppc-C₄ appeared without any duplication event. Nevertheless, caution is needed since the sampling of our study is still far from comprehensive. Further investigation with an increased sampling is recommended to elucidate the evolutionary changes underlying ppc-C₄ gene evolution in grasses.

Mutant huntingtin's effects on striatal gene expression in mice recapitulate changes observed in human Huntington's disease brain and do not differ with mutant huntingtin length or wild-type huntingtin dosage.

To test the hypotheses that mutant huntingtin protein length and wild-type huntingtin dosage have important effects on disease-related transcriptional dysfunction, we compared the changes in mRNA in seven genetic mouse models of Huntington's disease (HD) and postmortem human HD caudate. Transgenic models expressing short N-terminal fragments of mutant huntingtin (R6/1 and R6/2 mice) exhibited the most rapid effects on gene expression, consistent with previous studies. Although changes in the brains of knock-in and full-length transgenic models of HD took longer to appear, 15- and 22-month CHL2(Q150/Q150), 18-month Hdh(Q92/Q92) and 2-year-old YAC128 animals also exhibited significant HD-like mRNA signatures. Whereas it was expected that the expression of full-length huntingtin transprotein might result in unique gene expression changes compared with those caused by the expression of an N-terminal huntingtin fragment, no discernable differences between full-length and fragment models were detected. In addition, very high correlations between the signatures of mice expressing normal levels of wild-type huntingtin and mice in which the wild-type protein is absent suggest a limited effect of the wild-type protein to change basal gene expression or to influence the qualitative disease-related effect of mutant huntingtin. The combined analysis of mouse and human HD transcriptomes provides important temporal and mechanistic insights into the process by which mutant huntingtin kills striatal neurons. In addition, the discovery that several available lines of HD mice faithfully recapitulate the gene expression signature of the human disorder provides a novel aspect of validation with respect to their use in preclinical therapeutic trials.

Assessment of changes in body water by bioimpedance in acutely ill surgical patients.

OBJECTIVE: To evaluate the relationship between changes in body bioelectrical impedance (BI) at 0.5, 50 and kHz and the changes in body weight, as an index of total body water changes, in acutely ill surgical patients during the rapid infusion of isotonic saline solution. DESIGN: Prospective clinical study. SETTING: Multidisciplinary surgical ICU in a university hospital. PATIENTS: Twelve male patients treated for acute surgical illness (multiple trauma n = 5, major surgery n = 7). Selection criteria: stable cardiovascular parameters, normal cardiac function, signs of hypovolemia (CVP < or = 5 mmHg, urine output < 1 ml/kg x h). INTERVENTIONS: After baseline measurements, a 60 min fluid challenge test was performed with normal saline solution, 0.25 ml/kg/min [corrected]. MEASUREMENTS AND RESULTS: Body weight (platform digital scale), total body impedance (four-surface electrode technique; measurements at 0.5, 50 and 100 kHz) and urine output. Fluid retention induced a progressive decrease in BI at 0.5, 50 and 100 kHz, but the changes were significant for BI 0.5 and BI 100 only, from 40 min after the beginning of the fluid therapy onwards. There was a significant negative correlation between changes in water retention and BI 0.5, with individual correlation coefficients ranging from -0.72 to 0.95 (p < 0.01-0.0001). The slopes of the regression lines indicated that for each kg of water change, there was a mean decrease in BI of 18 ohm, but a substantial inter-individual variability was noted. CONCLUSION: BI measured at low frequency can represent a valuable index of acute changes in body water in a group of surgical patients but not in a given individual.

A selective nociceptive block is not sufficient to prevent central changes after peripheral nerve injury

Background: Providing analgesia without suppressing motor or sensory function is a challenge for regional anesthesia and postoperative pain management. Resiniferatoxin (RTX), an ultrapotent agonist for transient receptor potential subtype-1 (TRPV1) can produce this selective blockade, as TRPV1 is selectively expressed on nociceptors. Futhermore, after peripheral nerve injury, spontaneous ectopic activity arises from all types of nerve fibers that can affect spinal neurons and glial cells. The goal of the present experiment is to determine whether spontaneous activity generated in C-fibers or in both A&C-fibers is required for microglia activation. Method: We applied RTX (0.01%) or bupivacaine microspheres to the sciatic nerve of rats to block the conduction of C-fibers or A&C-fibers, respectively, before spared nerve injury (SNI). Behavior was tested and all the rats were sacrificed 2 days later; immunohistochemistry was performed on their spinal cord for mitogen-activated protein kinase (MAPK) p38, bromodeoxyuridine (BrdU, marker of proliferation) and Iba1 (microglial marker). Result: At day 2 after SNI robust mechanical allodynia and p38 activation in spinal microglia were documented. There was also a substantial cell proliferation in the spinal cord, all proliferating cells (BrdU+) being microglia (Iba1+). RTX blocked heat sensitivity and produced heat hypoalgesia without affecting mechanical allodynia and motor function. Microglial proliferation and p38 activation in the spinal cord were not affected by RTX (p >0.05). In contrast, a complete sensory and motor blockade was seen with bupivacaine which also significantly inhibited p38 activation and microglial proliferation in the spinal cord (p <0.05). Conclusion: We conclude that (1) RTX can provide a selective nociceptive blockade but that (2) blocking only nociceptive fibers does not impair the development of mechanical allodynia and microglia activation. Therefore (3) if microglia activation is important for chronic pain development then specific nociceptive blockade won't be sufficient to prevent it.