Longitudinal changes in neurometabolite concentrations in the dorsal anterior cingulate cortex after concentrated exposure therapy for obsessive-compulsive disorder

Background The dorsal anterior cingulate cortex (dACC) plays an important role in the pathophysiology of obsessive-compulsive disorder (OCD) due to its role in error processing, cognitive control and emotion regulation. OCD patients have shown altered concentrations in neurometabolites in the dACC, particularly Glx (glutamate+glutamine) and tNAA (N-acetylaspartate+N-acetyl-aspartyl-glutamate). We investigated the immediate and prolonged effects of exposure and response prevention (ERP) on these neurometabolites. Methods Glx and tNAA concentrations were measured using magnetic resonance spectroscopy (1H-MRS) in 24 OCD patients and 23 healthy controls at baseline. Patients received concentrated ERP over four days. A subset was re-scanned after one week and three months. Results No Glx and tNAA abnormalities were observed in OCD patients compared to healthy controls before treatment or over time. Patients with childhood or adult onset differed in the change over time in tNAA (F(2,40) = 7.24, ɳ2p= 0.27, p = 0.004): concentrations increased between one week after treatment and follow-up in the childhood onset group (t(39) = -2.43, d = -0.86, p = 0.020), whereas tNAA concentrations decreased between baseline and follow-up in patients with an adult onset (t(42) = 2.78, d = 1.07, p = 0.008). In OCD patients with versus without comorbid mood disorders, lower Glx concentrations were detected at baseline (t(38) = -2.28, d = -1.00, p = 0.028). Glx increased after one week of treatment within OCD patients with comorbid mood disorders (t(30) = -3.09, d = -1.21, p = 0.004). Limitations Our OCD sample size allowed the detection of moderate to large effect sizes only. Conclusion ERP induced changes in neurometabolites in OCD seem to be dependent on mood disorder comorbidity and disease stage rather than OCD itself.publishedVersio

Long range allostery mediates cooperative adenine nucleotide binding by the Ski2 like RNA helicase Brr2

Brr2 is an essential Ski2 like RNA helicase that exhibits a unique structure among the spliceosomal helicases. Brr2 harbors a catalytically active N terminal helicase cassette and a structurally similar but enzymatically inactive C terminal helicase cassette connected by a linker region. Both cassettes contain a nucleotide binding pocket, but it is unclear whether nucleotide binding in these two pockets is related. Here we use biophysical and computational methods to delineate the functional connectivity between the cassettes and determine whether occupancy of one nucleotide binding site may influence nucleotide binding at the other cassette. Our results show that Brr2 exhibits high specificity for adenine nucleotides, with both cassettes binding ADP tighter than ATP. Adenine nucleotide affinity for the inactive C terminal cassette is more than two orders of magnitude higher than that of the active N terminal cassette, as determined by slow nucleotide release. Mutations at the intercassette surfaces and in the connecting linker diminish the affinity of adenine nucleotides for both cassettes. Moreover, we found that abrogation of nucleotide binding at the C terminal cassette reduces nucleotide binding at the N terminal cassette 70 away. Molecular dynamics simulations identified structural communication lines that likely mediate these long range allosteric effects, predominantly across the intercassette interface. Together, our results reveal intricate networks of intramolecular interactions in the complex Brr2 RNA helicase, which fine tune its nucleotide affinities and which could be exploited to regulate enzymatic activity during splicin

Chronic care for heart failure patients: who to refer back to the general practitioner?: Experiences of the Dutch integrated heart failure care model

ObjectiveThe number of patients with heart failure (HF) and corresponding burden of the healthcare system will increase significantly. The Dutch integrated model, 'Transmural care of HF Patients' was based on the European Society of Cardiology (ESC) guidelines and initiated to manage the increasing prevalence of HF patients in primary and secondary care and stimulate integrated care. It is unknown how many HF patients are eligible for back-referral to general practitioners (GPs), which is important information for the management of chronic HF care. This study aims to evaluate clinical practice of patients for whom chronic HF care can be referred from the cardiologist to the GP based on the aforementioned chronic HF care model.Design and MethodsA retrospective case record-based study was conducted, which included all chronic HF patients registered in the cardiology information systems of two different hospitals. Subsequently, 200 patients were randomly selected for evaluation. The following patients were considered eligible for referral to the GP: 1/Stable HF patients with reduced left ventricular ejection fraction (LVEF), 2/Stable HF patients with a recovered LVEF and 3/Stable HF patients with a preserved LVEF, 4/HF, palliative setting.ResultsOf the 200 patients, 17% was considered eligible for referral to the GP. This group consisted of 5% patients with a reduced LVEF, 10.5% patients with recovered LVEF and 1.5% patients with a preserved LVEF. Main indicators for HF care by cardiologists were active cardiac disease other than HF (39.5%), recent admission for HF (29.5%) or a recent adjustment in HF medication (7.5%).ConclusionApplying the chronic HF care model of the 'Transmural care of HF patients' and the ESC-guidelines, results in an important opportunity to further optimise HF integrated care and to deal with the increasing number of HF patients referred to the hospital