The Apc1638N mouse model, which carries a targeted mutant allele within the adenomatous polyposis (Apc) gene and develops intestinal tumours spontaneously, predominantly in the small bowel, was used ...to investigate the effects of two potential chemopreventive agents, aspirin and α-amylase resistant starch (RS). Heterozygous Apc+/Apc1638N mice were fed semi-purified diets rich in animal fat, animal proteins and sucrose and low in dietary fibre (Western style diets) from ~6 weeks up to 6 months of age. Two of the diets contained aspirin (300 mg/kg diet) and two RS (1:1 mixture of raw potato starch: Hylon VII at 200 g/kg diet) in a 2×2 factorial design. A fifth treatment group were fed a conventional rodent chow diet. The mice fed the Western style diets became almost three times as fat as the chow-fed mice but this did not affect tumour yield. Treatment with RS resulted in significantly more intestinal tumours whereas aspirin alone had no effect. However, there was a significant aspirin×RS interaction, which suggests that aspirin could prevent the small intestine tumour-enhancing effects of RS in this Apc-driven tumorigenesis model. The possibility that large amounts of purified forms of resistant starch may have adverse effects within the small bowel is a novel observation that requires further investigation since greater intakes of starchy foods (and of RS) are being encouraged as a public health measure in compensation for reduced dietary fat intake. However, it remains possible that any increased risk is restricted to carriers of germline mutations in APC.
To determine how rapidly trimethoprim-sulfamethoxazole affects serum total thyroxine (T4) and thyroid-stimulating hormone (TSH) concentrations in euthyroid dogs and how quickly hormone concentrations ...return to reference values following discontinuation of administration.
Prospective study.
7 healthy euthyroid dogs.
Dogs were given trimethoprim-sulfamethoxazole (26.5 to 31.3 mg/kg 12 to 14.2 mg/lb, PO, q 12 h) for a maximum of 6 weeks. A CBC and Schirmer tear test were performed and serum total T4 and TSH concentrations were measured weekly. Administration of trimethoprim-sulfamethoxazole was discontinued if total T4 concentration was less than the lower reference limit and TSH concentration was greater than the upper reference limit or if persistent neutropenia developed.
Six dogs had total T4 concentrations less than the lower reference limit within 3 weeks; T4 concentration was decreased after 1 week in 3 of these 6 dogs. In these 6 dogs, TSH concentration was greater than the upper reference limit within 4 weeks. In 1 dog, T4 and TSH concentrations were not affected, despite administration of trimethoprim-sulfamethoxazole for 6 weeks. Neutropenia developed in 4 dogs. In 1 dog, the neutropenia resolved while trimethoprim-sulfamethoxazole was still being administered. In the other 3, neutrophil counts returned to reference values 1 week after drug administration was discontinued.
Results suggest that administration of trimethoprim-sulfamethoxazole at a dosage of 26.5 to 31.3 mg/kg, PO, every 12 hours can substantially alter serum total T4 and TSH concentrations and neutrophil counts in dogs within as short a time as a few weeks.
Law-Abiding Causal Decision Theory Williamson, Timothy L.; Sandgren, Alexander
The British journal for the philosophy of science,
12/2023, Letnik:
74, Številka:
4
Journal Article
Recenzirano
Odprti dostop
In this article we discuss how causal decision theory should be modified to handle a class of problematic cases involving deterministic laws. Causal decision theory, as it stands, is problematically ...biased against your endorsing deterministic propositions (for example, it tells you to deny Newtonian physics, regardless of how confident you are of its truth). Our response is that this is not a problem for causal decision theory per se, but arises because of the standard method for assessing the truth of certain counterfactuals. The truth of deterministic laws is ‘modally fragile’ on the standard semantics for counterfactuals: if determinism is true and you were to do otherwise, the laws would be different. We provide two ways of avoiding this problem: (1) supplement the standard semantics for counterfactuals with impossible worlds, or (2) introduce rigid designators into the description of problematic decision situations. We argue that both of these approaches are well motivated and can be readily incorporated into Lewisian causal decision theory.
Furthermore, Miller comments that "echinacea lacks the 1,2-unsaturated necine ring associated with hepatotoxicity of pyrrolizidine alkaloids", confirming that echinacea is not hepatotoxic. ...Holden ...and colleagues fail to report that Fugh-Berman immediately contested the suggestion that echinacea might be hepatotoxic. 3 A review of the safety of echinacea demonstrates that although there have been reports of allergic reactions, no deaths, dose dependent adverse effects, or overdoses have been reported. ...our study raises the alarm, proposes vigilance, and reminds us that we should be inquiring directly about herbal remedies when recording a patient's history.
...recent research has begun to uncover narratives of female young professionals who experience pay, benefits and career advancement discrimination based on age and gender (see Duncan and Loretto's ..."Never the Right Age? The ultimate impact of gendered ageism for young women professionals is that they wait until later to nurture their career development by producing knowledge or becoming involved in the field. ...higher education and student affairs is delayed in receiving the time, talents and treasures that our institutions, organizations and communities would receive from young women professionals.
Fluoride is considered one of the most phytotoxic elements to plants, and indicative fluoride injury has been associated over a wide range of foliar fluoride concentrations. The aim of this study was ...to determine the probability of indicative foliar fluoride injury based on
Acer
sp. foliar fluoride concentrations using a logistic regression model. Foliage from
Acer nedundo
,
Acer saccharinum
,
Acer saccharum and Acer platanoides
was collected along a distance gradient from three separate brick manufacturing facilities in southern Ontario as part of a long-term monitoring programme between 1995 and 2014. Hydrogen fluoride is the major emission source associated with the manufacturing facilities resulting with highly elevated foliar fluoride close to the facilities and decreasing with distance. Consistent with other studies, indicative fluoride injury was observed over a wide range of foliar concentrations (9.9–480.0 μg F
−
g
−1
). The logistic regression model was statistically significant for the
Acer
sp. group,
A. negundo
and
A. saccharinum
; consequently,
A. negundo
being the most sensitive species among the group. In addition,
A. saccharum
and
A. platanoides
were not statistically significant within the model. We are unaware of published foliar fluoride values for
Acer
sp. within Canada, and this research provides policy maker and scientist with probabilities of indicative foliar injury for common urban
Acer
sp. trees that can help guide decisions about emissions controls. Further research should focus on mechanisms driving indicative fluoride injury over wide ranging foliar fluoride concentrations and help determine foliar fluoride thresholds for damage.
The purpose of this study was to determine the separate and combined effects of exercise and insulin on the activation of phosphatidylinositol 3-kinase (PI3-kinase) and glycogen synthase in human ...skeletal muscle in vivo. Seven healthy men performed three trials in random order. The trials included 1) ingestion of 2 g/kg body wt carbohydrate in a 10% solution (CHO); 2) 75 min of semirecumbent cycling exercise at 75% of peak O(2) consumption; followed by 5 x 1-min maximal sprints (Ex); and 3) Ex, immediately followed by ingestion of the carbohydrate solution (ExCHO). Plasma glucose and insulin were increased (P < 0.05) at 15 and 30 (Post-15 and Post-30) min after the trial during CHO and ExCHO, although insulin was lower for ExCHO. Hyperinsulinemia during recovery in CHO and ExCHO led to an increase (P < 0.001) in PI3-kinase activity at Post-30 compared with basal, although the increase was lower (P < 0. 004) for ExCHO. Furthermore, PI3-kinase activity was suppressed (P < 0.02) immediately after exercise (Post-0) during Ex and ExCHO. Area under the insulin response curve for all trials was positively associated with PI3-kinase activity (r = 0.66, P < 0.001). Glycogen synthase activity did not increase during CHO but was increased (P < 0.05) at Post-0 and Post-30 during Ex and ExCHO. Ingestion of the drink increased (P < 0.05) carbohydrate oxidation during CHO and ExCHO, although the increase after ExCHO was lower (P < 0.05) than CHO. Carbohydrate oxidation was directly correlated with PI3-kinase activity for all trials (r = 0.63, P < 0.001). In conclusion, under resting conditions, ingestion of a carbohydrate solution led to activation of the PI3-kinase pathway and oxidation of the carbohydrate. However, when carbohydrate was ingested after intense exercise, the PI3-kinase response was attenuated and glycogen synthase activity was augmented, thus facilitating nonoxidative metabolism or storage of the carbohydrate. Activation of glycogen synthase was independent of PI3-kinase.
Generating strange interactions in particle suspensions Martin, James E.; Anderson, Robert A.; Williamson, Rodney L.
Composites science and technology,
06/2003, Letnik:
63, Številka:
8
Journal Article, Conference Proceeding
Recenzirano
When a soft magnetic particle suspension is subjected to a vertical uniaxial magnetic field the particles polarize, the
positive dipolar interactions causing particle chain formation. If instead an ...audio-frequency rotating magnetic field is applied in a horizontal plane, the particles experience an average interaction that to first order is a
negative dipolar interaction, causing particle sheet formation in the biaxial field plane. When a vertical unaixial field and a horizontal biaxial field are simultaneously applied with the field amplitudes balanced, the positive and negative dipolar interactions cancel to first order, and one might expect no dipolar interactions at all. But in this
balanced triaxial field an isotropic second-order dipolar interaction of surprising magnitude remains. This classical triaxial interaction can be attractive or repulsive, and exhibits strong many-body interactions that lead to a variety of unexpected effects, including stable clusters with molecular geometries, the emergence of a particle foam, and the production of vortices in the fluid. By manipulating the triaxial field, a variety of particle structures can be made that cannot be produced by any other known means.
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