Sara Klein

Assay validation of phosphorylated S6 ribosomal protein for a pharmacodynamic monitoring of mTOR-inhibitors in peripheral human blood.

Therapeutic drug monitoring (TDM) of immunosuppressive drugs after organ transplantation is based on measuring blood levels alone, which often results in under‐ or over‐immunosuppression. Previous studies have shown the potential of measuring pharmacodynamic drug effects for TDM, but assessment of biomarkers for individual drugs is still not clinical routine. Therefore, we validated a specific assay to measure the pharmacodynamic effects of mammalian target of rapamycin (mTOR)‐inhibitors on phosphorylated S6 ribosomal protein (p‐S6RP), a downstream target of mTOR.

Effect of mixing dietary fibre (purified lignocellulose or purified pectin) and a corn meal on glucose and insulin responses in healthy horses

The aim of this study was to investigate the effect of the addition of a purified soluble (pectin) and insoluble (lignocellulose) fibre to a starchy meal on post-prandial glucose and insulin responses in healthy horses. Four horses were fed in a randomized order three different diets: (i) cracked corn, (ii) cracked corn mixed with purified lignocellulose, and (iii) cracked corn mixed with purified pectin. Each diet was adjusted to a starch intake of 2 g/kg bodyweight (BW). Lignocellulose was aligned to an intake of 0.2 g/kg BW, and pectin was fed in a dosage of 0.1 g/kg BW. Each period consisted of a 10-day acclimatization to the diet (fed once per day); during this time, the horses were fed 1.2 kg hay/100 kg BW/day. Blood was collected after each acclimatization period before and after the test meal was fed, without any hay. The increase in plasma glucose and insulin, peak values, and area under the curves were similar for all diets. The present findings suggest that adding purified soluble or insoluble fibre to a corn meal does not affect post-prandial glucose and insulin responses in healthy horses. Feeding strategies for horses with a high energy requirement should include a starch reduction per meal, rather than the addition of purified fibre.

Short-term effects of a moderate fish oil or soybean oil supplementation on postprandial glucose and insulin responses in healthy horses.

The aim of this study was to investigate the effects of fat supplementation on postprandial glycaemic and insulinaemic responses in horses fed a corn meal. Four horses were fed three different diets: (1) cracked corn (CC), (2) cracked corn with soybean oil (CC+SBO), and (3) cracked corn with fish oil (CC+FO). Each diet was adjusted so there was a starch intake of 2 g/kg bodyweight (BW) and an intake of 0.2 mL/kg BW of FO and SBO. The increases in mean plasma glucose and insulin concentrations, peak values, and areas under the curve were similar for all diets (time P<0.05, diet not significant). The addition of FO or SBO at 0.2 mL/kg BW to a starchy meal did not affect acute glucose and insulin responses. To avoid high postprandial glycaemic and insulinaemic responses feeding strategies should be designed primarily to reduce starch intake rather than the addition of fat.

Effects of feeding state on glycaemic and insulinaemic responses to a starchy meal in horses: a methodological approach.

A standardised methodology is required for classification of starchy diets. One important question is what feeding status is optimal to describe glycaemic and insulinaemic responses to the respective starchy diet. Four horses were fed, in a randomised order, four different feeding protocols relative to offering hay before or after cracked corn (CC): (i) ad libitum hay for 12 h before feeding CC and ad libitum hay after CC intake for 9 h (+CC+), (ii) ad libitum hay for 12 h before feeding CC and no hay after CC intake for 9 h (+CC-), (iii) feed restriction for 12 h before feeding CC and ad libitum hay after CC intake for 9 h (-CC+) and (iv) 1.2 kg hay/100 kg body weight (BW) per day, divided into two equal portions and offered at 0900 h and 1900 h, feed restriction for 12 h before feeding CC and no hay after CC intake for 9 h (-CC-). CC intake was adjusted to a starch intake of 2 g/kg BW. The different hay offerings did not affect basal plasma glucose and insulin levels. A significant rise in plasma glucose and insulin was found after CC intake for all diets. The highest peak glucose levels were analysed for -CC+, and the lowest glucose peaks were found for +CC- (diet P < 0.05). The highest insulin peaks were monitored for -CC+ (31.27 ± 18.19 μU/ml) and lower peaks for +CC- (13.36 ± 2.93 μU/ml) (diet P < 0.05). Insulin for -CC- and +CC- returned to resting values about 300 min after CC feeding. For +CC+ and -CC+, insulin levels were still above resting levels 510 min after CC intake (diet P < 0.05). The present data suggest that feed restriction for 12 h before feeding the starchy diet and no further roughage intake during blood sampling period provide the best-defined conditions.

Early Effects in Perivascular Nerves and Arterial Media Following Renal Artery Denervation

In the past years 2 different innovative methods of hypertension treatments were investigated. The first is the promising examination of the electrical activation of the carotid baroreceptors, which is now in the phase III studies,1,2 and second the usage of selective renal sympathetic denervation (RSD) as an alternative treatment in therapy-resistant hypertension. RSD is thought to be based on alteration of the sympathetic innervation of kidney and secondary effects on the renin–angiotensin–aldosterone system. The renal nerves are located in close vicinity to the renal artery wall. Their activation could be important for the progression of therapy-resistant hypertension. In this context, Krum et al3 showed the proof of principle of a percutaneous, catheter-based trail to destroy renal sympathetic nerves by the introduction of a RF catheter into the lumen of the main renal artery and its subsequent connection to a radiofrequency generator. Until recently, the renal denervation seemed to be a promising therapy option for antihypertensive treatment. However, the simplicity HTN-3 study as recently announced4 indicated a lack of effect of RSD. Nevertheless, at present, the underlying molecular mechanisms remain unclear during RSD. RF injury might damage the tissue by thermal coagulation but may also cause apoptosis as observed in colon cancer.5 Thus, we made up the hypothesis that RSD may induce apoptosis in the perivascular nerves. The initiation of apoptosis is still not entirely understood. One important pathway is the release of apoptosis-inducing factor (AIF) from the mitochondrial intermembrane space together with cytochrome c .6 Subsequently, AIF translocates to the nucleus and induces chromatin decondensation and DNA degradation, likely by endonucleases. Typically, when inducing apoptosis, AIF and caspases act together. However, AIF may induce cell death in a caspase-independent manner.7 The extrinsic pathway …