Increased brain cortical thickness associated with visceral fat in adolescents.

BACKGROUND: There has been a growing amount of evidence indicating that excess visceral fat is associated with alterations in brain structure and function, including brain cortical thinning in adults. OBJECTIVES: This study aims to investigate the relationship between brain cortical thickness with obesity assessments, in adolescents. METHODS: In this study, we measured three different obesity assessments within an adolescent population (aged 15 - 18 years): body mass index (BMI), visceral fat ratio measured with an MRI and hepatorenal gradient measured with an ultrasound. Volunteers also underwent an MRI scan to measure brain structure. RESULTS: Results indicated that there was no relationship of BMI or hepatorenal gradient with brain cortical dimensions. However, there was a significant association between visceral fat ratio and an increase of cortical thickness throughout the brain. CONCLUSIONS: These results suggest that visceral fat, but not BMI, is correlated with cortical thickening in adolescence.

Impulsivity-based thrifty eating phenotype and the protective role of n-3 PUFAs intake in adolescents.

The goal of the present study was to investigate whether intrauterine growth restriction (IUGR) affects brain responses to palatable foods and whether docosahexaenoic acid (DHA, an omega-3 fatty acid that is a primary structural component of the human brain) serum levels moderate the association between IUGR and brain and behavioral responses to palatable foods. Brain responses to palatable foods were investigated using a functional magnetic resonance imaging task in which participants were shown palatable foods, neutral foods and non-food items. Serum DHA was quantified in blood samples, and birth weight ratio (BWR) was used as a proxy for IUGR. The Dutch Eating Behavior Questionnaire (DEBQ) was used to evaluate eating behaviors. In the contrast palatable food > neutral items, we found an activation in the right superior frontal gyrus with BWR as the most important predictor; the lower the BWR (indicative of IUGR), the greater the activation of this region involved in impulse control/decision making facing the viewing of palatable food pictures versus neutral items. At the behavioral level, a general linear model predicting external eating using the DEBQ showed a significant interaction between DHA and IUGR status; in IUGR individuals, the higher the serum DHA, the lower is external eating. In conclusion, we suggest that IUGR moderates brain responses when facing stimuli related to palatable foods, activating an area related to impulse control. Moreover, higher intake of n-3 PUFAs can protect IUGR individuals from developing inappropriate eating behaviors, the putative mechanism of protection would involve decreasing intake in response to external food cues in adolescents/young adults.

Bacterial community dynamics in horizontal flow constructed wetlands with different plants for high salinity industrial wastewater polishing.

This study is focused on the diversity of bacterial communities from two series of horizontal subsurface flow constructed wetlands (CW) polishing high salinity tannery wastewater. Each series was planted with Arundo donax or Sarcocornia sp. in a substrate composed by expanded clay and sand. Chemical and biochemical oxygen demand removal efficiencies were similar in each series, varying between 58 and 67% (inlet COD 218 ± 28 mg L(-1)) and 60 and 77% (inlet BOD(5) 37 ± 6 mg L(-1)), respectively. High numbers of culturable bacteria were obtained from substrate and root samples - 5.75 × 10(6)-3.95 × 10(8) CFU g(-1) recovered on marine agar and 1.72 × 10(7)-8.46 × 10(8) CFU g(-1) on nutrient agar. Fifty bacterial isolates were retrieved from the CW, related phylogenetically to Firmicutes, Actinobacteria, Bacteroidetes, α-, ß-, and γ-Proteobacteria. Changes in the bacterial communities, from roots and substrate of each series, related to the plant species, hydraulic loading rates and along CW operation were examined using denaturating gradient gel electrophoresis (DGGE). The clustering analysis suggested that a diverse and distinct bacterial community inhabits each series, which was related to the type of plant present in each CW.

The effects of stimulus modality and frequency of stimulus presentation on cross-modal distraction.

Selective attention produces enhanced activity (attention-related modulations [ARMs]) in cortical regions corresponding to the attended modality and suppressed activity in cortical regions corresponding to the ignored modality. However, effects of behavioral context (e.g., temporal vs. spatial tasks) and basic stimulus properties (i.e., stimulus frequency) on ARMs are not fully understood. The current study used functional magnetic resonance imaging to investigate selectively attending and responding to either a visual or auditory metronome in the presence of asynchronous cross-modal distractors of 3 different frequencies (0.5, 1, and 2 Hz). Attending to auditory information while ignoring visual distractors was generally more efficient (i.e., required coordination of a smaller network) and less effortful (i.e., decreased interference and presence of ARMs) than attending to visual information while ignoring auditory distractors. However, these effects were modulated by stimulus frequency, as attempting to ignore auditory information resulted in the obligatory recruitment of auditory cortical areas during infrequent (0.5 Hz) stimulation. Robust ARMs were observed in both visual and auditory cortical areas at higher frequencies (2 Hz), indicating that participants effectively allocated attention to more rapidly presented targets. In summary, results provide neuroanatomical correlates for the dominance of the auditory modality in behavioral contexts that are highly dependent on temporal processing.

The neural networks underlying auditory sensory gating.

One of the most consistent electrophysiological deficits reported in the schizophrenia literature is the failure to inhibit, or properly gate, the neuronal response to the second stimulus of an identical pair (i.e., sensory gating). Although animal and invasive human studies have consistently implicated the auditory cortex, prefrontal cortex and hippocampus in mediating the sensory gating response, localized activation in these structures has not always been reported during non-invasive imaging modalities. In the current experiment, event-related FMRI and a variant of the traditional gating paradigm were utilized to examine how the gating network differentially responded to the processing of pairs of identical and non-identical tones. Two single-tone conditions were also presented so that they could be used to estimate the HRF for paired stimuli, reconstructed based on actual hemodynamic responses, to serve as a control non-gating condition. Results supported an emerging theory that the gating response for both paired-tone conditions was primarily mediated by auditory and prefrontal cortex, with potential contributions from the thalamus. Results also indicated that the left auditory cortex may play a preferential role in determining the stimuli that should be inhibited (gated) or receive further processing due to novelty of information. In contrast, there was no evidence of hippocampal involvement, suggesting that future work is needed to determine what role it may play in the gating response.

Morphological and molecular characterization of different Echinochloa spp. and Oryza sativa populations.

Echinochloa P. Beauv. is an important genus because many of its species are weeds infesting most paddy fields, which can reduce the rice grain production by up to 80%. A controversy exists about the taxonomy of the genus due to the high level of morphological variations found in these species. Cyhalofop-butyl, an aryloxyphenoxy-propionate herbicide, is used to control Echinochloa spp. in paddy fields, although differences in susceptibility were found between different Echinochloa species. E. colona was highly susceptible [ED50= 34 g of active ingredient (ai) ha(-1)]; very similar results were obtained with the remaining species. By contrast, E. oryzicola (170 g of ai ha(-1)) was less sensitive, with the herbicide symptoms appearing later. Because of this differential susceptibility, morphological and molecular studies were carried out. A morphological study, using 21 characters both quantitative and qualitative of spikelets and seedlings, was capable of clearly distinguishing closely related E. crus-galli plants (two populations), E. muricata and E. crus-pavonis, and E. oryzicola, E. utilis, and E. colona species. The resolution of Echinochloa species at the molecular level, based on RAPD analyses, was fairly consistent with morphological analysis results. Among the 60 primers screened, 21 primers exhibited polymorphic bands and produced a total of 136 RAPD markers. Of all the amplified fragments, 90 were found to be polymorphic. E. oryzicola and E. colona were clearly separated, and the RAPD analyses showed that both E. crus-galli populations were 100% related and 51% related to E. utilis, whereas E. crus-pavonis and E. muricata (73% similarity) appeared as being clearly separated from this group.

Isolation and characterization of polymeric galloyl-ester-degrading bacteria from a tannery discharge place.

The culturable bacteria colonizing the rhizosphere of plants growing in the area of discharge of a tannery effluent were characterized. Relative proportions of aerobic, denitrifying, and sulfate-reducing bacteria were determined in the rhizosphere of Typha latifolia, Canna indica, and Phragmites australis. Aerobic bacteria were observed to be the most abundant group in the rhizosphere, and plant type did not seem to influence the abundance of the bacterial types analyzed. To isolate bacteria able to degrade polyphenols used in the tannery industry, enrichments were conducted under different conditions. Bacterial cultures were enriched with individual polyphenols (tannins Tara, Quebracho, or Mimosa) or with an undefined mixture of tannins present in the tannery effluent as carbon source. Cultures enriched with the effluent or Tara tannin were able to degrade tannic acid. Six bacterial isolates purified from these mixed cultures were able to use tannic acid as a sole carbon source in axenic culture. On the basis of 16S ribosomal DNA sequence analysis, these isolates were closely related to organisms belonging to the taxa Serratia, Stenotrophomonas maltophilia, Klebsiella oxytoca, Herbaspirillum chlorophenolicum, and Pseudomonas putida.

Biodegradation of simazine in olive fields.

Simazine (2-chloro-4, bis ethylamino-1,3,5-triazine) is a herbicide of the s-triazine group used mainly to control broad-leaved weeds in different crops. Several papers report about simazine and other s-triazine derivates as being actual polluting agents. In fact, simazine has been detected in groundwater and soil. Since this herbicide has been extensively used in Andalusia (south of Spain), we are analyzing the levels of simazine residues found in the soil of olive fields. We are also simazine could be detected isolating live micro organisms able to degrade this compound, and are characterizing the metabolic pathways leading to this degradation and the fate of this compound in nature. With all these data in mind, we will try to develop a strategy for the bioremediation of contaminated soils. We have taken samples of soil from many olive orchards of Andalusia that have been treated with simazine. These samples were located with the help of a handheld GPS. The presence of simazine of these samples was detected by HPLC. In most of the samples taken no, and those where it could be, contained very low levels of this herbicide (lower than 0.5 ppm). Soil samples are being characterized to determine their physicochemical characteristics [pH, organic matter, texture, etc), and we are attempting to correlate all these parameters with the presence or absence of simazine. From some of the soils, we have isolated a group of micro organisms that can grow using simazine as the sole carbon and nitrogen sources. We are analyzing how the addition of carbon or nitrogen can influence the rate of the simazine degradation.

Detection of mycoplasmal infections in blood of patients with rheumatoid arthritis.

OBJECTIVE: Mycoplasmal infections are associated with several acute and chronic illnesses. Some mycoplasmas can enter a variety of tissues and cells, and cause system-wide or systemic signs and symptoms. METHODS: Patients (14 female, 14 male) diagnosed with rheumatoid arthritis (RA) were investigated for mycoplasmal infections in their blood leucocytes using a forensic polymerase chain reaction (PCR) procedure. Amplification was performed with genus- and species-specific primers, and a specific radiolabelled internal probe was used for Southern hybridization with the PCR product. Patients were investigated for the presence of Mycoplasma spp., and positive cases were further tested for infections with the following species: M. fermentans, M. hominis, M. pneumoniae and M. penetrans. RESULTS: The Mycoplasma spp. sequence, which is not entirely specific for mycoplasmas, was amplified from the peripheral blood of 15/28 patients (53.6%) and specific PCR products could not be detected in 13 patients (46.4%). Significant differences (P < 0.001) were found between patients and positive healthy controls in the genus test (3/32) and in the specific tests (0/32). Moreover, the incidence of mycoplasmal infections was similar in female and male patients. Using species-specific primers, we were able to detect infections with M. fermentans (8/28), M. pneumoniae (5/28), M. hominis (6/28) and M. penetrans (1/28) in RA patients. In 36% of the patients, we observed more than one Mycoplasma species in the blood leucocytes. All multiple infections occurred as combinations of M. fermentans with other species. CONCLUSIONS: The results suggest that a high percentage of RA patients have systemic mycoplasmal infections. Systemic mycoplasmal infections may be an important cofactor in the pathogenesis of RA, and their role needs to be explored further.

Resistance to Phosphinothricin (Glufosinate) and Its Utilization as a Nitrogen Source by Chlamydomonas reinhardtii.

Wild-type strain 21gr of the green alga Chlamydomonas reinhardtii was resistant to the ammonium salt of l-phosphinothricin (PPT, also called glufosinate), an irreversible inhibitor of glutamine synthetase activity and the main active component of the herbicide BASTA (AgrEvo, Frankfurt am Main, Germany). Under the same conditions, however, this strain was highly sensitive to l-methionine-S-sulfoximine, a structural analog of PPT which has been reported to be 5 to 10 times less effective than PPT as an inhibitor in plants. Moreover, this alga was able to grow with PPT as the sole nitrogen source when this compound was provided at low concentrations. This utilization of PPT was dependent upon the addition of acetate and light and did not take place in the presence of ammonium. Resistance was due neither to the presence of N-acetyltransferase or transaminase activity nor to the presence of glutamine synthetase isoforms resistant to PPT. By using l-[methyl-(sup14)C]PPT, we demonstrated that resistance is due to lack of PPT transport into the cells. This strongly suggests that PPT and l-methionine-S-sulfoximine enter the cells through different systems. Growth with PPT is supported by its deamination by an l-amino acid oxidase activity which has been previously described to be located at the periplasm.

Characterization of a Mutant of Chlamydomonas reinhardtii That Uses L-Methionine-S-Sulfoximine and Phosphinothricin as Nitrogen Sources for Growth.

A strain of Chlamydomonas reinhardtii, named ARF-1, which grows with the glutamine synthetase (GS) inhibitor L-methionine-S-sulfoximine (MSX), has been isolated and characterized. Mutant ARF-1 is affected at a single and dominant gene, tentatively assigned to the allele msr-1-2. Neither the uptake of ammonia nor the two GS isoenzyme activities of the mutant were affected by MSX in vivo. GS activities, however, were fully abolished in vitro, thus suggesting that neither GS isoform was an altered enzyme resistant to the inhibitor. Resistance to MSX does not seem to be due to either a defect in a permease responsible for the transport of MSX or over-expression of GS activity, nor did we find an alternative enzymatic pathway for the assimilation of ammonium. Resistance was independent of the nitrogen source used and was strongly enhanced by the addition of acetate. Unlike the parental strain, mutant ARF-1 can degrade and utilize MSX as the sole nitrogen source for growth, which could account for the observed resistance. Thus, this mutant can be classified as a novel type of MSX-resistant mutant. This mutant can also use phosphinothricin, methionine sulfone, or methionine sulfoxide as the sole sources of nitrogen. This capability cosegregated in the genetic crosses and was also observed in all the diploids isolated. An MSX/[alpha]-ketoglutarate aminotransferase activity, not present in the parental strain 305, was detected in mutant ARF-1 cells. Therefore, we propose that the locus msr-1-2 either codes for this transaminase activity or its product gene is necessary to express this transaminase activity.

Induction and superinduction of auxin-responsive mRNAs with auxin and protein synthesis inhibitors.

We have identified a class of small mRNAs (approximately 0.5 kilobases), referred to as small auxin-up RNAs (SAURs), that increases in abundance within minutes after auxin application to excised elongating hypocotyl sections of soybean. In this study, we present evidence that SAURs accumulate in the absence of auxin when protein synthesis is inhibited. Superinduction of SAURs occurs if the synthetic auxin 2,4-dichlorophenoxyacetic acid is added under conditions where protein synthesis is inhibited. Transcription run-on experiments with isolated nuclei show that, unlike 2,4-dichlorophenoxyacetic acid, protein synthesis inhibitors do not activate transcription of the SAUR genes. These results suggest that protein synthesis inhibitors act by stabilizing SAURs and that some labile protein(s) are involved in the rapid turnover of SAURs. This stabilization is not observed with GH3, another auxin-inducible mRNA. Whether induced with 2,4-dichlorophenoxyacetic acid or cycloheximide, SAURs are primarily expressed in epidermal and cortical cells of elongating hypocotyl sections, with little or no expression in vascular tissue. Unlike 2,4-dichlorophenoxyacetic acid-induced SAUR accumulation, the increase in abundance of SAURs induced by cycloheximide is transient, with a peak approximately 1 h after inhibitor addition. Complete inhibition of protein synthesis is not required for SAUR accumulation in the presence of protein synthesis inhibitors.

Regulation by ammonium of nitrate and nitrite assimilation in Chlamydomonas reinhardtii.

The inhibitor of mRNA synthesis, 6-methylpurine, inhibited nitrate reductase derepression in either ammonium-grown or methylammonium-treated wild-type cells of Chlamydomonas reinhardtii, but not in nitrogen-starved cells. In contrast, 6-methylpurine did not inhibit nitrate reductase synthesis in the methylammonium-resistant mutant 2170 (ma-1) either grown on ammonium, treated with methylammonium or nitrogen starved, but did inhibit the continuous synthesis of nitrate reductase, which required the presence of nitrate in the media. In both wild-type and mutant 2170 grown on ammonium and transferred to nitrate media, cycloheximide immediately prevented nitrate reductase derepression when added either at the beginning or at different times of induction treatment. Unlike wild-type cells, mutant 2170 was able to take up either nitrate or nitrite simultaneously with ammonium in whose presence nitrate and nitrite reductases were synthesized. However, synthesis of nitrate reductase was progressively inhibited in the mutant cells when the intracellular ammonium levels were raised as a result of an increase in either the external pH or the extracellular ammonium concentrations. The results rule out the existence of maturase-like proteins in Chlamydomonas and indicate that ammonium has a double effect on the regulation of nitrate reductase synthesis: (a) it prevents nitrate reductase mRNA production; and (b) it controls negatively the expression of this mRNA.

Two different carriers transport both ammonium and methylammonium in Chlamydomonas reinhardtii.

A new methylammonium-resistant mutant strain from Chlamydomonas reinhardtii, henceforth termed 2172 (ma-2), has been isolated. This mutant is affected in a single mendelian gene different from and linked to the ma-1 locus which is defective in the methylammonium-resistant mutant 2170. Both mutations in ma-1 (2170) and ma-2 (2172) are linked to the nit-1 gene coding for the nitrate reductase apoenzyme. Mutant 2172 is affected in methylammonium but not in ammonium uptake capacity and shows derepressed nitrate and nitrite reductase activities in media containing nitrate plus methylammonium but not in nitrate plus ammonium media. The following two enzymatic components for the transport of both ammonium and methylammonium in wild-type cells have been identified: component 1, with high Vmax and K values, which is constitutive, and component 2, with low Vmax and K values, which is ammonium-repressible. Mutant 2170 lacks component 1 whereas mutant 2172 lacks component 2 for both methylammonium and ammonium transport. From genetic and kinetic evidences we conclude that in C. reinhardtii two different carriers are responsible for the transport of both ammonium and methylammonium and that methylammonium (ammonium) transport is a reversible process probably inhibited by the intracellular ammonium which, in turn, regulates nitrate and nitrite reductase levels.

Involvement of Reversible Inactivation in the Regulation of Nitrate Reductase Enzyme Levels in Chlamydomonas reinhardtii.

All nitrate reductase-related activities of Chlamydomonas reinhardtii wild-type and mutant 305 cells were degraded in vivo under conditions in which the reversible inactivation could take place. When the enzyme was in the inactive form, half-lives of all nitrate reductase-related activities in wild and mutant 305 strains decreased significantly. The only nitrate reductase-related activity present in mutant 104, nitrate reductase-diaphorase, was incapable of undergoing reversible inactivation and was not degraded under any of the conditions tested. Addition of nitrate to inactive nitrate reductase of mutant 305 caused the in vivo reactivation of the enzyme and halted its degradation. Our results indicate that reversibly inactivated nitrate reductase from C. reinhardtii is the main target for a degradation system, and that nitrate reductase related diaphorase must be integrated in a reversibly inactive nitrate reductase complex to undergo degradation. A physiological role for the interconversion process of nitrate reductase can be understood on the basis of these facts.

Heteromultimeric structure of the nitrate reductase complex of Chlamydomonas reinhardii.

The NAD(P)H-nitrate reductase complex (overall-NR) of Chlamydomonas reinhardii exhibits two partial activities: NAD(P)H-cytochrome c reductase (diaphorase) and reduced benzyl viologen-NR (terminal-NR). Mild tryptic digestion of the enzyme complex resulted in the loss of both overall and terminal-NR activities, whereas diaphorase activity remained unaltered. The diaphorase activity of mutant 104 and the terminal-NR activity of mutant 305 of C. reinhardii, which are the sole activities related to NR present in these mutants, responded to tryptic treatment to the same extent as the corresponding activities of the wild enzyme complex. Trypsin disassembled the 220-kd NR native complex by destroying the aggregation capability of the diaphorase subunits without affecting their activity nor molecular size (45 kd). A 67-kd thermostable protein, containing molybdenum co-factor, was also released from trypsin-treated NR. This protein lacked diaphorase and NR activities but was able to reconstitute the overall-NR complex by complementation with untreated diaphorase subunit of mutant 104. Our results support a tetrameric structure for the C. reinhardii NR complex, containing two kinds of subunits.

Avaliacao de um servico de abreugrafia dentro de um hospital universitario Aspectos preventivos de educacao medica. / Evaluation of a fluoroscopic service in an university hospital - Preventive aspects of medical education

Os autores avaliam a eficacia de um servico de abreugrafia dentro de um hospital universitario (HC-FMRP-USP) analisando os beneficios resultantes para os pacientes que se submeteram ao exame abreugrafico. Estudam qual e o grau de preocupacao por parte do medico na utilizacao de exames complementares na assistencia medica. Efetuaram a revisao de 10.444 prontuarios medicos de pacientes abreugrafados no periodo setembro/1967 a setembro/1970.Apresentam a prevalencia das anormalidades radiologicas encontradas, numero de pacientes nos quais foi surgida feitura de exames complementares (decorrentes dos achados abreugraficos), porcentagem de casos e tempo medio em que a sugestao foi atendida, bem como a percentagem de pacientes beneficiados pelo fato de terem se submetido ao exame abreugrafico. Discutem aspectos da educacao medica envolvida na utilizacao de exames complementares, como e o caso da abreugrafia, dentro de um hospital universitario. Reafirmam o valor da mesma mostrando sua eficacia e eficiencia como processo de "screenning" para doencas dos sistemas cardiorespiratorio e osteo-muscular