629 research outputs found
Galactose Ingested with a High-Fat Beverage Increases Postprandial Lipemia Compared with Glucose but Not Fructose Ingestion in Healthy Men.
BACKGROUND: Fructose ingestion with a high-fat beverage increases postprandial lipemia when compared with glucose. It is unknown whether other sugars, such as galactose, also increase postprandial lipemia. OBJECTIVES: The objective was to assess whether galactose ingestion within a high-fat beverage increases postprandial lipemia relative to glucose or fructose. METHODS: Two experiments were conducted, which contrasted different test drinks under otherwise standardized conditions. In Experiment 1, 10 nonobese men (age: 22 ± 1 y; BMI, 23.5 ± 2.2 kg/2) ingested either galactose or glucose (0.75 g supplemented carbohydrate per⋅kilogram body mass) within a high-fat test drink (0.94 g fat per kilogram body mass). In Experiment 2, a separate group of 9 nonobese men (age: 26 ± 6 y; BMI: 23.5 ± 2.6 kg/m2) ingested either galactose or fructose (identical doses as those in Experiment 1) within the same high-fat test drink. Capillary blood was sampled before and at frequent intervals after ingestion of the test drinks for a 300-min period to determine plasma triacylglycerol, glucose, lactate, nonesterified fatty acid, and insulin concentrations. Paired t tests and 2-way, repeated-measures ANOVA were used to compare conditions within each experiment. RESULTS: The incremental AUC for triacylglycerol was greater following galactose ingestion compared with glucose (127 ± 59 compared with 80 ± 48 mmol⋅L-1 × 300 min, respectively; P = 0.04) but not compared with fructose (136 ± 74 compared with 133 ± 63 mmol⋅L-1 ×300 min, respectively; P = 0.91). Plasma lactate concentrations also increased to a greater extent with galactose compared with glucose ingestion (time-condition interaction: P < 0.001) but not fructose ingestion (time-condition interaction: P = 0.17). CONCLUSIONS: Galactose ingestion within a high-fat beverage exacerbates postprandial lipemia and plasma lactate concentrations compared with glucose but not fructose in nonobese men. These data suggest that galactose metabolism may be more similar to fructose than to glucose, providing a rationale to reassess the metabolic fate of galactose ingestion in humans. This trial was registered at clinicaltrials.gov as NCT03439878
Functional analysis of altered Tenascin isoform expression in breast cancer
Background:
Cellular interactions with the extracellular matrix (ECM) control many aspects of cell function. The complex ECM protein Tenascin-C (TN), which exists as multiple isoforms, is upregulated in breast cancer. We previously have identified a change in the TN isoform profile in breast cancer, with detection of two additional isoforms — TN16 and TN14/16 — not seen in normal breast [1]. The purpose of this study was to investigate directly the effects of these tumour-associated TNC isoforms on breast cancer cell behaviour
PubChem3D: Similar conformers
<p>Abstract</p> <p>Background</p> <p>PubChem is a free and open public resource for the biological activities of small molecules. With many tens of millions of both chemical structures and biological test results, PubChem is a sizeable system with an uneven degree of available information. Some chemical structures in PubChem include a great deal of biological annotation, while others have little to none. To help users, PubChem pre-computes "neighboring" relationships to relate similar chemical structures, which may have similar biological function. In this work, we introduce a "Similar Conformers" neighboring relationship to identify compounds with similar 3-D shape and similar 3-D orientation of functional groups typically used to define pharmacophore features.</p> <p>Results</p> <p>The first two diverse 3-D conformers of 26.1 million PubChem Compound records were compared to each other, using a shape Tanimoto (ST) of 0.8 or greater and a color Tanimoto (CT) of 0.5 or greater, yielding 8.16 billion conformer neighbor pairs and 6.62 billion compound neighbor pairs, with an average of 253 "Similar Conformers" compound neighbors per compound. Comparing the 3-D neighboring relationship to the corresponding 2-D neighboring relationship ("Similar Compounds") for molecules such as caffeine, aspirin, and morphine, one finds unique sets of related chemical structures, providing additional significant biological annotation. The PubChem 3-D neighboring relationship is also shown to be able to group a set of non-steroidal anti-inflammatory drugs (NSAIDs), despite limited PubChem 2-D similarity.</p> <p>In a study of 4,218 chemical structures of biomedical interest, consisting of many known drugs, using more diverse conformers per compound results in more 3-D compound neighbors per compound; however, the overlap of the compound neighbor lists per conformer also increasingly resemble each other, being 38% identical at three conformers and 68% at ten conformers. Perhaps surprising is that the average count of conformer neighbors per conformer increases rather slowly as a function of diverse conformers considered, with only a 70% increase for a ten times growth in conformers per compound (a 68-fold increase in the conformer pairs considered).</p> <p>Neighboring 3-D conformers on the scale performed, if implemented naively, is an intractable problem using a modest sized compute cluster. Methodology developed in this work relies on a series of filters to prevent performing 3-D superposition optimization, when it can be determined that two conformers cannot possibly be a neighbor. Most filters are based on Tanimoto equation volume constraints, avoiding incompatible conformers; however, others consider preliminary superposition between conformers using reference shapes.</p> <p>Conclusion</p> <p>The "Similar Conformers" 3-D neighboring relationship locates similar small molecules of biological interest that may go unnoticed when using traditional 2-D chemical structure graph-based methods, making it complementary to such methodologies. The computational cost of 3-D similarity methodology on a wide scale, such as PubChem contents, is a considerable issue to overcome. Using a series of efficient filters, an effective throughput rate of more than 150,000 conformers per second per processor core was achieved, more than two orders of magnitude faster than without filtering.</p
Cytogerontology since 1881: A reappraisal of August Weismann and a review of modern progress
Cytogerontology, the science of cellular ageing, originated in 1881 with the prediction by August Weismann that the somatic cells of higher animals have limited division potential. Weismann's prediction was derived by considering the role of natural selection in regulating the duration of an organism's life. For various reasons, Weismann's ideas on ageing fell into neglect following his death in 1914, and cytogerontology has only reappeared as a major research area following the demonstration by Hayflick and Moorhead in the early 1960s that diploid human fibroblasts are restricted to a finite number of divisions in vitro.
In this review we give a detailed account of Weismann's theory, and we reveal that his ideas were both more extensive in their scope and more pertinent to current research than is generally recognised. We also appraise the progress which has been made over the past hundred years in investigating the causes of ageing, with particular emphasis being given to (i) the evolution of ageing, and (ii) ageing at the cellular level. We critically assess the current state of knowledge in these areas and recommend a series of points as primary targets for future research
Ill or just old? Towards a conceptual framework of the relation between ageing and disease
BACKGROUND: Is this person ill or just old? This question reflects the pondering mind of a doctor while interpreting the complaints of an elderly person who seeks his help. Many doctors think that ageing is a non-disease. Accordingly, various attempts have been undertaken to separate pathological ageing from normal ageing. However, the existence of a normal ageing process distinct from the pathological processes causing disease later in life can be questioned. DISCUSSION: Ageing is the accumulation of damage to somatic cells, leading to cellular dysfunction, and culminates in organ dysfunction and an increased vulnerability to death. Analogously, chronic diseases initiate early in life and their development is slow before they become clinically apparent and culminate in disability or death. The definition of disease is also subject to current opinions and scientific understanding and usually, it is an act of individual creativity when physical changes are recognised as symptoms of a new disease. New diseases, however, are only rarely really new. Most new diseases have gone undiagnosed because their signs and symptoms escaped recognition or were interpreted otherwise. Many physical changes in the elderly that are not yet recognised as a disease are thus ascribed to normal ageing. Therefore, the distinction between normal ageing and disease late in life seems in large part arbitrary. SUMMARY: We think that normal ageing cannot be separated from pathological processes causing disease later in life, and we propose that the distinction is avoided
Evaluation of a Bayesian inference network for ligand-based virtual screening
Background
Bayesian inference networks enable the computation of the probability that an event will occur. They have been used previously to rank textual documents in order of decreasing relevance to a user-defined query. Here, we modify the approach to enable a Bayesian inference network to be used for chemical similarity searching, where a database is ranked in order of decreasing probability of bioactivity.
Results
Bayesian inference networks were implemented using two different types of network and four different types of belief function. Experiments with the MDDR and WOMBAT databases show that a Bayesian inference network can be used to provide effective ligand-based screening, especially when the active molecules being sought have a high degree of structural homogeneity; in such cases, the network substantially out-performs a conventional, Tanimoto-based similarity searching system. However, the effectiveness of the network is much less when structurally heterogeneous sets of actives are being sought.
Conclusion
A Bayesian inference network provides an interesting alternative to existing tools for ligand-based virtual screening
Intravenous fluid prescription practices among pediatric residents in Korea
PurposeRecent studies have established the association between hypotonic fluids administration and hospital-acquired hyponatremia in children. The present paper investigated the pattern of current practice in intravenous fluid prescription among Korean pediatric residents, to underscore the need for updated education.MethodsA survey-based analysis was carried out. Pediatric residents at six university hospitals in Korea completed a survey consisting of four questions. Each question proposed a unique scenario in which the respondents had to prescribe either a hypotonic or an isotonic fluid for the patient.ResultsNinety-one responses were collected and analyzed. In three of the four scenarios, a significant majority prescribed the hypotonic fluids (98.9%, 85.7%, and 69.2%, respectively). Notably, 69.2% of the respondents selected the hypotonic fluids for postoperative management. Almost all (96.7%) selected the isotonic fluids for hydration therapy.ConclusionIn the given scenarios, the majority of Korean pediatric residents would prescribe a hypotonic fluid, except for initial hydration. The current state of pediatric fluid management, notably, heightens the risk of hospital-acquired hyponatremia. Updated clinical practice education on intravenous fluid prescription, therefore, is urgently required
Evolutionarily Conserved Substrate Substructures for Automated Annotation of Enzyme Superfamilies
The evolution of enzymes affects how well a species can adapt to new environmental conditions. During enzyme evolution, certain aspects of molecular function are conserved while other aspects can vary. Aspects of function that are more difficult to change or that need to be reused in multiple contexts are often conserved, while those that vary may indicate functions that are more easily changed or that are no longer required. In analogy to the study of conservation patterns in enzyme sequences and structures, we have examined the patterns of conservation and variation in enzyme function by analyzing graph isomorphisms among enzyme substrates of a large number of enzyme superfamilies. This systematic analysis of substrate substructures establishes the conservation patterns that typify individual superfamilies. Specifically, we determined the chemical substructures that are conserved among all known substrates of a superfamily and the substructures that are reacting in these substrates and then examined the relationship between the two. Across the 42 superfamilies that were analyzed, substantial variation was found in how much of the conserved substructure is reacting, suggesting that superfamilies may not be easily grouped into discrete and separable categories. Instead, our results suggest that many superfamilies may need to be treated individually for analyses of evolution, function prediction, and guiding enzyme engineering strategies. Annotating superfamilies with these conserved and reacting substructure patterns provides information that is orthogonal to information provided by studies of conservation in superfamily sequences and structures, thereby improving the precision with which we can predict the functions of enzymes of unknown function and direct studies in enzyme engineering. Because the method is automated, it is suitable for large-scale characterization and comparison of fundamental functional capabilities of both characterized and uncharacterized enzyme superfamilies
Rehabilitation goals of people with spinal cord injuries can be classified against the International Classification of Functioning, Disability and Health Core Set for spinal cord injuries
Objectives:
To establish whether inter-professional rehabilitation goals from people with non-traumatic spinal cord injury (SCI) can be classified against the International Classification of Functioning, Disability and Health (ICF) SCI Comprehensive and Brief Core Sets early postacute situation.
Setting:
Neurological rehabilitation unit.
Methods:
Rehabilitation goals of 119 patients with mainly incomplete and non-traumatic SCIs were classified against the ICF SCI Core Sets following established linking rules.
Results:
A total of 119 patients generated 1509 goals with a mean (and s.d.) of 10.5 (9.1) goals per patient during the course of their inpatient rehabilitation stay. Classifying the 1509 rehabilitation goals against the Comprehensive ICF Core Set generated 2909 ICF codes. Only 69 goals (4.6%) were classified as ‘not definable (ND)’. Classifying the 1509 goals against the Brief ICF Core Set generated 2076 ICF codes. However, 751(49.8%) of these goals were classified as ‘ND’. In the majority of goals (95.7%), the ICF code description was not comprehensive enough to fully express the goals set in rehabilitation. In particular, the notion of quality of movement or specificity and measurability aspects of a goal (usually described with the criteria and acronyms SMART) could not be expressed through the ICF codes.
Conclusion:
Inter-professional rehabilitation goals can be broadly described by the ICF Comprehensive Core Set for SCI but not the Brief Core Set
Prediction of Dengue Disease Severity among Pediatric Thai Patients Using Early Clinical Laboratory Indicators
Patients with severe dengue illness typically develop complications in the later stages of illness, making early clinical management of all patients with suspected dengue infection difficult. An early prediction tool to identify which patients will have a severe dengue illness will improve the utilization of limited hospital resources in dengue endemic regions. We performed classification and regression tree (CART) analysis to establish predictive algorithms of severe dengue illness. Using a Thai hospital pediatric cohort of patients presenting within the first 72 hours of a suspected dengue illness, we developed diagnostic decision algorithms using simple clinical laboratory data obtained on the day of presentation. These algorithms correctly classified near 100% of patients who developed a severe dengue illness while excluding upwards of 50% of patients with mild dengue or other febrile illnesses. Our algorithms utilized white blood cell counts, percent white blood cell differentials, platelet counts, elevated aspartate aminotransferase, hematocrit, and age. If these algorithms can be validated in other regions and age groups, they will help in the clinical management of patients with suspected dengue illness who present within the first three days of fever onset
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