994 resultados para Short Questions


Relevância:

20.00% 20.00%

Publicador:

Resumo:

BACKGROUND/AIM: We have reported that neonatal treatment with monosodium L-glutamate (MSG), which causes damage to the arcuate nucleus, leads to severe hyperleptinemia and reduced adrenal leptin receptor (ob-Rb) expression in adulthood. As a result, rats given MSG neonatally display corticoadrenal leptin-resistance, a defect that is overridden by normalization of corticoadrenal hyperfunction. The aim of the present study was to determine whether negative energy conditions could correct corticoadrenal cell dysfunction in rats given MSG neonatally. METHODS: Normal (CTR) and MSG-treated female rats were subjected to food removal for 1-5 days, or prolonged (24-61 days) food restriction (FR). Plasma levels of several biomarkers and in vitro corticoadrenal function were evaluated following starvation or FR. RESULTS: Fasting for 1-5 days reduced plasma leptin levels in CTR and MSG rats, compared to levels in the respective groups fed ad libitum(p < 0.05), but adrenal leptin-resistance was unchanged. With prolonged FR, isolated adrenal cells from MSG rats became sensitive to leptin, which lowered ACTH-induced glucocorticoid release. This restoration of leptin response was associated with normalization of adrenal ob-Rb gene expression. CONCLUSION: Dietary restriction in some leptin-resistant obese phenotypes may normalize adrenocortical function.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is an increasing utilisation of oral creatine (Cr) supplementation among athletes who hope to enhance their performance but it is not known if this ingestion has any detrimental effect on the kidney. Five healthy men ingested either a placebo or 20 g of creatine monohydrate per day for 5 consecutive days. Blood samples and urine collections were analysed for Cr and creatinine (Crn) determination after each experimental session. Total protein and albumin urine excretion rates were also determined. Oral Cr supplementation had a significant incremental impact on arterial content (3.7 fold) and urine excretion rate (90 fold) of this compound. In contrast, arterial and urine Crn values were not affected by the Cr ingestion. The glomerular filtration rate (Crn clearance) and the total protein and albumin excretion rates remained within the normal range. In conclusion, this investigation showed that short-term oral Cr supplementation does not appear to have any detrimental effect on the renal responses of healthy men.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Visual implant elastomer (VIE) has recently been employed to investigate different aspects of earthworm ecology. However, a number of fundamental questions relating to the detection and positioning of the tag, its persistence and potential effects on earthworms remain unknown. Seven earthworm species belonging to three ecological groupings, with different pigmentation and burrowing behaviour, were tagged using different coloured VIE. External inspection after two days, one week and 1, 10 and 27 months were followed by preservation, dissection and internal inspection. Tags could be seen in living specimens to 27 months, and dissection revealed that in most cases they were lodged in the coelomic cavity, held in place by septa. However, over longer time periods (more than two years), the chlorogogenous tissue tended to bind to the tags and made external observation increasingly difficult. Migration of the VIE material towards the posterior of the earthworm and potential loss of the tag were only observed on rare occasions, and a recovery rate in excess of 98% was recorded. By introducing a reasonable amount of VIE into segments, just after the clitellum, this technique can become a valuable tool in earthworm ecology and life history studies, particularly in short-medium term laboratory and field experiments.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVE: To determine whether differences in short-term virologic failure among commonly used antiretroviral therapy (ART) regimens translate to differences in clinical events in antiretroviral-naïve patients initiating ART. DESIGN: Observational cohort study of patients initiating ART between January 2000 and December 2005. SETTING: The Antiretroviral Therapy Cohort Collaboration (ART-CC) is a collaboration of 15 HIV cohort studies from Canada, Europe, and the United States. STUDY PARTICIPANTS: A total of 13 546 antiretroviral-naïve HIV-positive patients initiating ART with efavirenz, nevirapine, lopinavir/ritonavir, nelfinavir, or abacavir as third drugs in combination with a zidovudine and lamivudine nucleoside reverse transcriptase inhibitor backbone. MAIN OUTCOME MEASURES: Short-term (24-week) virologic failure (>500 copies/ml) and clinical events within 2 years of ART initiation (incident AIDS-defining event, death, and a composite measure of these two outcomes). RESULTS: Compared with efavirenz as initial third drug, short-term virologic failure was more common with all other third drugs evaluated; nevirapine (adjusted odds ratio = 1.87, 95% confidence interval (CI) = 1.58-2.22), lopinavir/ritonavir (1.32, 95% CI = 1.12-1.57), nelfinavir (3.20, 95% CI = 2.74-3.74), and abacavir (2.13, 95% CI = 1.82-2.50). However, the rate of clinical events within 2 years of ART initiation appeared higher only with nevirapine (adjusted hazard ratio for composite outcome measure 1.27, 95% CI = 1.04-1.56) and abacavir (1.22, 95% CI = 1.00-1.48). CONCLUSION: Among antiretroviral-naïve patients initiating therapy, between-ART regimen, differences in short-term virologic failure do not necessarily translate to differences in clinical outcomes. Our results should be interpreted with caution because of the possibility of residual confounding by indication.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Iowa Department of Transportation (DOT) has made improving work zone (WZ) safety a high priority. Managing vehicle speeds through work zones is perceived to be an important factor in achieving this goal. A number of speed reduction techniques are currently used by transportation agencies throughout the country to control speeds and reduce speed variation at work zones. The purpose of this project is to study these and other applicable work zone speed reduction strategies. Furthermore, this research explores transportation agencies' policies regarding managing speeds in long-term, short-term, and moving work zones. This report consists of three chapters. The first chapter, a literature review, examines the current speed reduction practices at work zones and provides a review of the relevant literature. The speed control strategies reviewed in this chapter range from posting regulatory and advisory speed limit signs to using the latest radar technologies to reduce speeds at work zones. The second chapter includes a short write-up for each identified speed control technique. The write-up includes a description, the results of any field tests, the benefits and the costs of the technology or technique. To learn more about other state policies regarding work zone speed reduction and management, the Center for Transportation Research and Education conducted a survey. The survey consists of six multipart questions. The third chapter provides summaries of the response to each question.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Land plants have had the reputation of being problematic for DNA barcoding for two general reasons: (i) the standard DNA regions used in algae, animals and fungi have exceedingly low levels of variability and (ii) the typically used land plant plastid phylogenetic markers (e.g. rbcL, trnL-F, etc.) appear to have too little variation. However, no one has assessed how well current phylogenetic resources might work in the context of identification (versus phylogeny reconstruction). In this paper, we make such an assessment, particularly with two of the markers commonly sequenced in land plant phylogenetic studies, plastid rbcL and internal transcribed spacers of the large subunits of nuclear ribosomal DNA (ITS), and find that both of these DNA regions perform well even though the data currently available in GenBank/EBI were not produced to be used as barcodes and BLAST searches are not an ideal tool for this purpose. These results bode well for the use of even more variable regions of plastid DNA (such as, for example, psbA-trnH) as barcodes, once they have been widely sequenced. In the short term, efforts to bring land plant barcoding up to the standards being used now in other organisms should make swift progress. There are two categories of DNA barcode users, scientists in fields other than taxonomy and taxonomists. For the former, the use of mitochondrial and plastid DNA, the two most easily assessed genomes, is at least in the short term a useful tool that permits them to get on with their studies, which depend on knowing roughly which species or species groups they are dealing with, but these same DNA regions have important drawbacks for use in taxonomic studies (i.e. studies designed to elucidate species limits). For these purposes, DNA markers from uniparentally (usually maternally) inherited genomes can only provide half of the story required to improve taxonomic standards being used in DNA barcoding. In the long term, we will need to develop more sophisticated barcoding tools, which would be multiple, low-copy nuclear markers with sufficient genetic variability and PCR-reliability; these would permit the detection of hybrids and permit researchers to identify the 'genetic gaps' that are useful in assessing species limits.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The approval in 2004 of bevacizumab (Avastin), a neutralizing monoclonal antibody directed against vascular endothelial growth factor (VEGF) as the first anti-angiogenic systemic drug to treat cancer patients validated the notion introduced 33 years earlier by Dr. Judah Folkman, that inhibition of tumor angiogenesis might be a valid approach to control tumor growth. Anti-angiogenic therapy was greeted in the clinic a major step forward in cancer treatment. At the same time this success recently boosted the field to the quest for new anti-angiogenic targets and drugs. In spite of this success, however, some old questions in the field have remained unanswered and new ones have emerged. They include the identification for surrogate markers of angiogenesis and anti-angiogenesis, the understanding about how anti-angiogenic therapy and chemotherapy synergize, the characterization of the biological consequences of sustained suppression of angiogenesis on tumor biology and normal tissue homeostasis, and the mechanisms of tumor escape from anti-angiogenesis. In this review we summarize some of these outstanding questions, and highlight future challenges in clinical, translational and experimental research in anti-angiogenic therapy that need to be addressed in order to improve current treatments and to design new drugs.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Spirochetal infections present with a variety of clinical syndromes and epidemiologic features. Diagnosis remains challenging for the clinician because of the often protean clinical presentation and poor performance of stan-dard microbiological tests. We present 3 clinical cases, illustrating interesting or unusual features of these infections. First, we present a case of leptospirosis acquired in Switzerland after a rat bite. We then present a case of early disseminated Lyme disease with multiple erythema migrans, lymphopenia, thrombocytopenia and liver enzyme elevation. Finally, we present a case of secondary syphilis in an HIV-positive man, complicated by sensorineural deafness. For each case we highlight and discuss the specific epidemiological, clinical and therapeutic features.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Recent immunotherapy trials have shown that lymphodepletion induced by short-term chemotherapy favors subsequent expansion of adoptively transferred T cells, by homeostatic mechanisms. To take advantage of this effect, novel regimens are being developed with the aim to enhance tumor immunity and reduce treatment toxicity. We have designed a clinical phase I trial combining chemotherapy, reinfusion of PBMC containing Melan-A(MART-1)-specific T cells, and vaccination with Melan-A peptide in Incomplete Freund's Adjuvant. Treatment with Busulfan plus Fludarabine depleted lymphocytes only weakly. Cyclophosphamide (CTX) plus Fludarabine depleted lymphocytes more profoundly, with a maximal effect using high doses of CTX. It is interesting to note that, the degree of homeostatic T-cell proliferation correlated tightly with the extent of lymphodepletion. As compared with CD4 T cells, CD8 T cells showed higher susceptibility to chemotherapy, followed by more rapid homeostatic proliferation and recovery, resulting in strong inversions of CD4/CD8 ratios. Despite efficient homeostatic proliferation of total CD4 and CD8 T cells, the frequency of CD8 T cells specific for Melan-A and cancer-testis antigens remained relatively low. In contrast, EBV-specific T cells expanded and reached high numbers. We conclude that short-term chemotherapy promoted homeostatic lymphocyte proliferation depending on the intensity of lymphocyte depletion, however without preferential expansion of tumor antigen-specific T cells.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Amnestic mild cognitive impairment (aMCI) is characterized by memory deficits alone (single-domain, sd-aMCI) or associated with other cognitive disabilities (multi-domain, md-aMCI). The present study assessed the patterns of electroencephalographic (EEG) activity during the encoding and retrieval phases of short-term memory in these two aMCI subtypes, to identify potential functional differences according to the neuropsychological profile. Continuous EEG was recorded in 43 aMCI patients, whose 16 sd-aMCI and 27 md-aMCI, and 36 age-matched controls (EC) during delayed match-to-sample tasks for face and letter stimuli. At encoding, attended stimuli elicited parietal alpha (8-12 Hz) power decrease (desynchronization), whereas distracting stimuli were associated with alpha power increase (synchronization) over right central sites. No difference was observed in parietal alpha desynchronization among the three groups. For attended faces, the alpha synchronization underlying suppression of distracting letters was reduced in both aMCI subgroups, but more severely in md-aMCI cases that differed significantly from EC. At retrieval, the early N250r recognition effect was significantly reduced for faces in md-aMCI as compared to both sd-aMCI and EC. The results suggest a differential alteration of working memory cerebral processes for faces in the two aMCI subtypes, face covert recognition processes being specifically altered in md-aMCI.