Ubiquitylome profiling of Parkin-null brain reveals dysregulation of calcium homeostasis factors ATP1A2, Hippocalcin and GNA11, reflected by altered firing of noradrenergic neurons.

Parkinson's disease (PD) is the second most frequent neurodegenerative disorder in the old population. Among its monogenic variants, a frequent cause is a mutation in the Parkin gene (Prkn). Deficient function of Parkin triggers ubiquitous mitochondrial dysfunction and inflammation in the brain, but it remains unclear how selective neural circuits become vulnerable and finally undergo atrophy. We attempted to go beyond previous work, mostly done in peripheral tumor cells, which identified protein targets of Parkin activity, an ubiquitin E3 ligase. Thus, we now used aged Parkin-knockout (KO) mouse brain for a global quantification of ubiquitylated peptides by mass spectrometry (MS). This approach confirmed the most abundant substrate to be VDAC3, a mitochondrial outer membrane porin that modulates calcium flux, while uncovering also >3-fold dysregulations for neuron-specific factors. Ubiquitylation decreases were prominent for Hippocalcin (HPCA), Calmodulin (CALM1/CALML3), Pyruvate Kinase (PKM2), sodium/potassium-transporting ATPases (ATP1A1/2/3/4), the Rab27A-GTPase activating protein alpha (TBC1D10A) and an ubiquitin ligase adapter (DDB1), while strong increases occurred for calcium transporter ATP2C1 and G-protein subunits G(i)/G(o)/G(Tr). Quantitative immunoblots validated elevated abundance for the electrogenic pump ATP1A2, for HPCA as neuron-specific calcium sensor, which stimulates guanylate cyclases and modifies axonal slow afterhyperpolarization (sAHP), and for the calcium-sensing G-protein GNA11. We assessed if compensatory molecular regulations become insufficient over time, leading to functional deficits. Patch clamp experiments in acute Parkin-KO brain slices indeed revealed alterations of the electrophysiological properties in aged noradrenergic locus coeruleus (LC) neurons. LC neurons of aged Parkin-KO brain showed an acceleration of the spontaneous pacemaker frequency, a reduction in sAHP and shortening of action potential duration, without modulation of KCNQ potassium currents. These findings indicate altered calcium-dependent excitability in a PARK2 model of PD, mediated by diminished turnover of potential Parkin targets such as ATP1A2 and HPCA. The data also identified further novel Parkin substrate candidates like SIRT2, OTUD7B and CUL5. Our elucidation of neuron-specific mechanisms of PD pathogenesis helps to explain the known exceptional susceptibility of noradrenergic and dopaminergic projections to alterations of calcium homeostasis and its mitochondrial buffering.

Long-term effective population size dynamics of an intensively monitored vertebrate population.

Long-term genetic data from intensively monitored natural populations are important for understanding how effective population sizes (Ne) can vary over time. We therefore genotyped 1622 common buzzard (Buteo buteo) chicks sampled over 12 consecutive years (2002-2013 inclusive) at 15 microsatellite loci. This data set allowed us to both compare single-sample with temporal approaches and explore temporal patterns in the effective number of parents that produced each cohort in relation to the observed population dynamics. We found reasonable consistency between linkage disequilibrium-based single-sample and temporal estimators, particularly during the latter half of the study, but no clear relationship between annual Ne estimates () and census sizes. We also documented a 14-fold increase in between 2008 and 2011, a period during which the census size doubled, probably reflecting a combination of higher adult survival and immigration from further afield. Our study thus reveals appreciable temporal heterogeneity in the effective population size of a natural vertebrate population, confirms the need for long-term studies and cautions against drawing conclusions from a single sample.

Multifocal sclerosing angiomatoid nodular transformation of the spleen in a patient with simultaneous metachronous liver metastasis after colon cancer surgery: a first case report.

Sclerosing angiomatoid nodular transformation of the spleen (SANT) is a benign, extremely rare vascular lesion of the spleen with unknown pathogenesis. SANT is often discovered incidentally, and can sometimes be found in patients with a history of cancer. Based on absent definitive radiological signs and varying growth patterns, distinction from malignant processes such as metastasis can be very difficult. Therefore, surgical resection of the spleen is indicated in most cases of patients with history of cancer. We report a case of a bifocal manifestation of SANT in the spleen in a patient with history of colon cancer and newly-diagnosed metachronous liver metastases.

Value of ultrasound (US)-guided percutaneous needle biopsy of detected pathological gastrointestinal (GI) tract lesions but negative or incomplete endoscopy.

PURPOSE: The study aim was to investigate the diagnostic value of US-guided percutaneous needle biopsy in the case of suspicious tumor lesion of the GI tract revealed by abdominal US but without detection with endoscopy or with incomplete or no possible endoscopy. PATIENTS AND METHODS: Over a defined time period, all consecutive patients with no appropriate endoscopic diagnostic specimen or finding were registered. The patient, diagnostic, and periinterventional characteristics were documented. RESULTS: In total, 16 patients (7 males; mean age, 63.2 [range, 43 - 90] years) were enrolled in this study representing a rare but possible constellation from endoscopic practice characterized by no detectable intraluminal tumor growth and a suspicious tumor lesion revealed with abdominal US as found in each case (n = 16) from 01 / 01 / 2003 - 12 / 31 / 2006. The main indications for needle biopsy were pathological colonic cockades (n = 7) and tumor lesions of the stomach and small intestine (n = 9). The first needle biopsy attempt was successful in all subjects (technical success rate: 100 %) using the color-coded US mode in each case (100 %). There were no postinterventional complications (rate: 0 %). CONCLUSION: Percutaneous US-guided needle biopsy can be considered a safe diagnostic tool for clarifying the differential diagnosis of suspicious tumor lesions of the GI tract (revealed originally only by abdominal US) as the next favorable diagnostic step in the rare situation that endoscopy cannot provide appropriate information, in order to shorten the diagnostic course, to achieve a therapeutic decision and to decrease effort and costs.

"Hemosuccus pancreaticus"--primarily ultrasound-guided successful intervention using transcutaneous fibrin glue application and histoacryl injection.

There is a broad spectrum of causes for upper gastrointestinal (GI) bleeding that can be stopped by various approaches. On the basis of the report of an extraordinary case, the favorable minimally invasive approach of applying fibrin glue and histoacryl/lipiodol to the vascular basis of a bleeding pseudoaneurysm leading to "Hemosuccus pancreaticus" as a rare cause of recurrent bleeding in the upper GI tract and dangerous complications in the case of chronic pancreatitis is described. There were recurrent bleeding episodes within the upper GI tract in a 40-year-old female patient. Her medical history was significant for chronic pancreatitis and pseudocyst. Abdominal ultrasound plus duplex ultrasonography revealed a pseudoaneurysm within the tail of the pancreas as the cause of "Hemosuccus pancreaticus". Ultrasound guidance was used to repeatedly apply 2 ml of fibrin glue and 2 x 2 ml of the mixture of lipiodol and histoacryl to the basis of the pseudoaneurysm which led to complete and permanent cessation of the bleeding. Immediate and follow-up control duplex ultrasonographies (up to one year) demonstrated sufficient exclusion of the pseudoaneurysm but a preservation of the lienal artery with no disturbance of the blood perfusion in the splenic parenchyma. In conclusion, this is one of the first reports of the successful cessation of recurrent bleeding into a pseudocyst out of pseudoaneurysm ("Hemosuccus pancreaticus") by an ultrasound-guided transcutaneous fibrin glue and histoacryl/lipiodol application, which 1. is recommended as an alternative but feasible and safe therapeutic tool, 2. can provide sufficient and permanent cessation of bleeding but preserve the perfusion of the natural vessel as an initial step in the possible therapeutic algorithm, and 3. can avoid, in case of success, more invasive approaches such as angiography-guided embolization with coils or implantation of a prosthesis and even open surgical intervention, in particular, in high-risk patients.