An emerging recombinant norovirus GII.P16/GII.4 Sydney 2012 strain caused a gastroenteritis outbreak amongst attendees at a large health function in regional New South Wales, Australia. This was the ...third outbreak caused by the recombinant GII.P16/GII.4 Sydney 2012 strain in this region in 2017, which appears to be emerging as a common strain in the Hunter New England region.
•Studies of neurocognitive outcomes post paediatric epilepsy surgery contain bias.•Both methodological and reporting biases were identified.•Number of common biases in studies was not associated with ...journal impact factor.•Journal impact factor is not a reliable indicator of quality within this field.
RCTs are the gold standard in determining intervention efficacy with journal impact factor assumed to index research quality. Flint et al’s (2017) systematic review examined neurocognitive outcomes following paediatric temporal lobe epilepsy surgery. Retrieved evidence was restricted to non-RCTs, which pose greater risk of bias and thus diminish research quality. The current study evaluated risk of bias in sources retrieved by Flint et al. and explored whether impact factor related to research quality within this selected field.
Methodological and reporting bias was evaluated using categories of bias specified by Cochrane. The relationship between the identified number of biases and journal impact factors of retrieved sources was examined.
All studies carried substantial risk for bias. Methodology bias included low sample size (76.71%; 56/73), risk of confounding cognitive outcomes due to failure to report pre-surgery neurocognitive data (21.92%; 16/73) and to determine whether patients were prescribed antiepileptic drugs at follow-up (53.42%; 39/73). Reporting bias included overstating claims based on findings (53.42%; 39/73), failure to report individual patient characteristics (66%; 33/50) and omitting the nature of surgical interventions (15.07%; 11/73). The number of sources of common bias within studies was not associated significantly with journal impact factor (p = .878).
This evaluation highlights risk of bias when sources are predominantly uncontrolled non-RCTs and provides evidence that journal impact factor is not a reliable indicator of quality within this field. Authors should limit bias in their methods and reporting of results, to ensure the highest quality evidence possible is used to inform treatment decisions and prognosis.
The effects of changes in the gut environment upon the human colonic microbiota are poorly understood. The response of human fecal microbial communities from two donors to alterations in pH (5.5 or ...6.5) and peptides (0.6 or 0.1%) was studied here in anaerobic continuous cultures supplied with a mixed carbohydrate source. Final butyrate concentrations were markedly higher at pH 5.5 (0.6% peptide mean, 24.9 mM; 0.1% peptide mean, 13.8 mM) than at pH 6.5 (0.6% peptide mean, 5.3 mM; 0.1% peptide mean, 7.6 mM). At pH 5.5 and 0.6% peptide input, a high butyrate production coincided with decreasing acetate concentrations. The highest propionate concentrations (mean, 20.6 mM) occurred at pH 6.5 and 0.6% peptide input. In parallel, major bacterial groups were monitored by using fluorescence in situ hybridization with a panel of specific 16S rRNA probes. Bacteroides levels increased from ca. 20 to 75% of total eubacteria after a shift from pH 5.5 to 6.5, at 0.6% peptide, coinciding with high propionate formation. Conversely, populations of the butyrate-producing Roseburia group were highest (11 to 19%) at pH 5.5 but fell at pH 6.5, a finding that correlates with butyrate formation. When tested in batch culture, three Bacteroides species grew well at pH 6.7 but poorly at pH 5.5, which is consistent with the behavior observed for the mixed community. Two Roseburia isolates grew equally well at pH 6.7 and 5.5. These findings suggest that a lowering of pH resulting from substrate fermentation in the colon may boost butyrate production and populations of butyrate-producing bacteria, while at the same time curtailing the growth of Bacteroides spp.
NMDA receptors play important roles in learning and memory and in sculpting neural connections during development. After the period of peak cortical plasticity, NMDA receptor-mediated EPSCs (NMDAR ...EPSCs) decrease in duration. A likely mechanism for this change in NMDA receptor properties is the molecular alteration of NMDA receptor structure by regulation of NMDA receptor subunit gene expression. The four modulatory NMDAR2A-D (NR2A-D) NMDA receptor subunits are known to alter NMDA receptor properties, and the expression of these subunits is regulated developmentally. It is unclear, however, how the four NR2 subunits are expressed in individual neurons and which NR2 subunits are important to the regulation of NMDA receptor properties during development in vivo. Analysis of NR2 subunit gene expression in single characterized neurons of postnatal neocortex revealed that cells expressing NR2A subunit mRNA had faster NMDAR EPSCs than cells not expressing this subunit, regardless of postnatal age. Expression of NR2A subunit mRNA in cortical neurons at even low levels seemed sufficient to alter the NMDA receptor time course. The proportion of cells expressing NR2A and displaying fast NMDAR EPSCs increased developmentally, thus providing a molecular basis for the developmental change in mean NMDAR EPSC duration.
The composition of diets consumed following weight loss (WL) can have a significant impact on satiety and metabolic health.
This study was designed to test the effects of including a nondigestible ...carbohydrate to achieve weight maintenance (WM) following a period of WL.
Nineteen volunteers 11 females and 8 males, aged 20–62 y; BMI (kg/m2): 27–42 consumed a 3-d maintenance diet (15%:30%:55%), followed by a 21-d WL diet (WL; 30%:30%:40%), followed by 2 randomized 10-d WM diets (20%:30%:50% of energy from protein:fat:carbohydrate) containing either resistant starch type 3 (RS-WM; 22 or 26 g/d for females and males, respectively) or no RS (C-WM) in a within-subject crossover design without washout periods. The primary outcome, WM after WL, was analyzed by body weight. Secondary outcomes of fecal microbiota composition and microbial metabolite concentrations and gut hormones were analyzed in fecal samples and blood plasma, respectively. All outcomes were assessed at the end of each dietary period.
Body weight was similar after the RS-WM and C-WM diets (90.7 and 90.8 kg, respectively), with no difference in subjectively rated appetite. During the WL diet period plasma ghrelin increased by 36% (P < 0.001), glucose-dependent insulinotropic polypeptide (GIP) decreased by 33% (P < 0.001), and insulin decreased by 46% (P < 0.001), but no significant differences were observed during the RS-WM and C-WM diet periods. Fasting blood glucose was lower after the RS-WM diet (5.59 ± 0.31 mmol/L) than after the C-WM diet 5.75 ± 0.49 mmol/L; P = 0.015; standard error of the difference between the means (SED): 0.09. Dietary treatments influenced the fecal microbiota composition (R2 = 0.054, P = 0.031) but not diversity.
The metabolic benefits, for overweight adults, from WL were maintained through a subsequent WM diet with higher total carbohydrate intake. Inclusion of resistant starch in the WM diet altered gut microbiota composition positively and resulted in lower fasting glucose compared with the control, with no apparent change in appetite. This trial was registered at clinicaltrials.gov as NCT01724411.
Butyrate arising from microbial fermentation is important for the energy metabolism and normal development of colonic epithelial cells and has a mainly protective role in relation to colonic disease. ...While certain dietary substrates such as resistant starch appear to be butyrogenic in the colon, it is not known to what extent these stimulate butyrate production directly, e.g. by promoting amylolytic species, or indirectly, e.g. through cross-feeding of fermentation products. Cultural and molecular studies indicate that the most numerous butyrate-producing bacteria found in human faeces are highly oxygen-sensitive anaerobes belonging to the Clostridial clusters IV and XIVa. These include many previously undescribed species related to
Eubacterium,
Roseburia,
Faecalibacterium and
Coprococcus whose distribution and metabolic characteristics are under investigation. A better understanding of the microbial ecology of colonic butyrate-producing bacteria will help to explain the influence of diet upon butyrate supply, and to suggest new approaches for optimising microbial activity in the large intestine.
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