Drug-induced mitochondrial dysfunction has been hypothesized to be an important determining factor in the onset of drug-induced liver injury. It is essential to develop robust screens with which to identify drug-induced mitochondrial toxicity and to dissect its role in hepatotoxicity. In this study we have characterised a mechanistically refined HepG2 model, using a panel of selected hepatotoxicants and non-hepatotoxicants. We have demonstrated that acute metabolic modification, via glucose-deprivation over a 4 h period immediately prior to compound addition, is sufficient to allow the identification of drugs which induce mitochondrial dysfunction, in the absence of cell death over a short exposure (2-8 h) using a plate-based screen to measure cellular ATP content and cytotoxicity. These effects were verified by measuring changes in cellular respiration, via oxygen consumption and extracellular acidification rates. Overall, these studies demonstrate the utility of HepG2 cells for the identification of mitochondrial toxins which act directly on the electron transport chain and that the dual assessment of ATP content alongside cytotoxicity provides an enhanced mechanistic understanding of the causes of toxicity.

It is concluded that purinergic, atropine-resistant contractions are present in some types of dysfunctional bladder, and these are not caused by a differential sensitivity of the muscle to ATP and cholinergic agonists.

Background Enhanced methods of drug monitoring are required to support the individualisation of antibiotic dosing. We report the first-in-human evaluation of real-time phenoxymethylpenicillin monitoring using a minimally invasive microneedle-based β-lactam biosensor in healthy volunteers.

It is concluded that purinergic, atropine-resistant contractions are present in some types of dysfunctional bladder, and these are not caused by a differential sensitivity of the muscle to ATP and cholinergic agonists.

What’s known on the subject? and What does the study add? The question to be addressed was whether bladder overactivity or obstruction in patients was associated with any changes to the contractile properties of the detrusor smooth muscle, and in addition were there age‐related and gender‐dependent differences in these? The study showed that neither age nor gender per se affected the contractile properties of the smooth muscle from the stable bladder. However, in the pathology groups there was an age‐dependent reduction of nerve‐dependent contractile function, and thus in the overactive bladder there is an age‐dependent functional deneravation. OBJECTIVE • To test the hypothesis that the in vitro contractile properties of human detrusor smooth muscle are dependent on the age, gender and lower urinary tract pathology of the patient. MATERIALS AND METHODS • Contractions were elicited in isolated human detrusor smooth muscle preparations by nerve‐mediated electrical field stimulation, agonist application (carbachol, α,β‐methylene ATP and high‐K solutions) or direct muscle electrical stimulation. • Biopsies (n= 227) were obtained from four groups of patients with: stable bladders (control), bladder outlet obstruction (BOO), idiopathic (IDO), or neurogenic (NDO) detrusor overactivity. RESULTS • The magnitude of nerve‐mediated contractions declined as a function of patients’ age in each of the BOO, IDO and NDO groups but not in the control group. • Contractions elicited by direct muscle activation (10 µm carbachol or electrical stimulation with 20 ms pulses in the presence of 1 µm tetrodotoxin) did not vary with patient age. • Carbachol contractions were significantly smaller in samples from NDO bladders. • Atropine resistance was more prevalent in the pathology groups compared with the control group and was greatest in the IDO group. There was no influence of age in the prevalence or magnitude of atropine‐resistant contractions in any group. • Muscle excitability to direct electrical stimulation was similar in all groups. CONCLUSIONS • In the human bladder there is no evidence for a decline of detrusor smooth muscle contractility or excitability as a function of age, nor any gender difference or presence of pathology. • In the pathology groups there was evidence for a decline of functional innervation with age.

It is concluded that both agonists are equipotent in increasing intracellular Ca2+, but by different routes. The generation of purinergic contractions in detrusor from unstable bladder is not due to altered sensitivities of the detrusor myocyte to ATP or cholinergic agonists.

Serial microsampling and DBS in exploratory mouse pharmacokinetic has been shown to provide superior data quality when compared with traditional plasma-based composite studies.

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