University of Tübingen

About: University of Tübingen is a education organization based out in Tübingen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 40555 authors who have published 84108 publications receiving 3015320 citations. The organization is also known as: Eberhard Karls University & Eberhard-Karls-Universität Tübingen.

Phloem loading and unloading of sugars and amino acids

Abstract: In terrestrial higher plants, phloem transport delivers most nutrients required for growth and storage processes. Some 90% of plant biomass, transported as sugars and amino nitrogen (N) compounds in a bulk flow of solution, is propelled though the phloem by osmotically generated hydrostatic pressure differences between source (net nutrient export) and sink (net nutrient import) ends of phloem paths. Source loading and sink unloading of sugars, amino N compounds and potassium largely account for phloem sap osmotic concentrations and hence pressure differences. A symplasmic component is characteristic of most loading and unloading pathways which, in some circumstances, may be interrupted by an apoplasmic step. Raffinose series sugars appear to be loaded symplasmically. However, sucrose, and probably certain amino acids, are loaded into minor veins from source leaf apoplasms by proton symporters localized to plasma membranes of their sieve element/companion cell (se/cc) complexes. Sucrose transporters, with complementary kinetic properties, are conceived to function as membrane transporter complexes that respond to alterations in source/sink balance. In contrast, symplasmic unloading is common for many sink types. Intervention of an apoplasmic step, distal from importing phloem, is reserved for special situations. Effluxers that release sucrose and amino acids to the surrounding apoplasm in phloem loading and unloading are yet to be cloned. The physiological behaviour of effluxers is consistent with facilitated membrane transport that can be energy coupled. Roles of sucrose and amino acid transporters in phloem unloading remain to be discovered along with mechanisms regulating symplasmic transport. The latter is hypothesized to exert significant control over phloem unloading and, in some circumstances, phloem loading.

Abeta is targeted to the vasculature in a mouse model of hereditary cerebral hemorrhage with amyloidosis.

Abstract: The E693Q mutation in the amyloid beta precursor protein (APP) leads to cerebral amyloid angiopathy (CAA), with recurrent cerebral hemorrhagic strokes and dementia. In contrast to Alzheimer disease (AD), the brains of those affected by hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) show few parenchymal amyloid plaques. We found that neuronal overexpression of human E693Q APP in mice (APPDutch mice) caused extensive CAA, smooth muscle cell degeneration, hemorrhages and neuroinflammation. In contrast, overexpression of human wild-type APP (APPwt mice) resulted in predominantly parenchymal amyloidosis, similar to that seen in AD. In APPDutch mice and HCHWA-D human brain, the ratio of the amyloid-beta40 peptide (Abeta40) to Abeta42 was significantly higher than that seen in APPwt mice or AD human brain. Genetically shifting the ratio of AbetaDutch40/AbetaDutch42 toward AbetaDutch42 by crossing APPDutch mice with transgenic mice producing mutated presenilin-1 redistributed the amyloid pathology from the vasculature to the parenchyma. The understanding that different Abeta species can drive amyloid pathology in different cerebral compartments has implications for current anti-amyloid therapeutic strategies. This HCHWA-D mouse model is the first to develop robust CAA in the absence of parenchymal amyloid, highlighting the key role of neuronally produced Abeta to vascular amyloid pathology and emphasizing the differing roles of Abeta40 and Abeta42 in vascular and parenchymal amyloid pathology.

Pembrolizumab plus axitinib versus sunitinib monotherapy as first-line treatment of advanced renal cell carcinoma (KEYNOTE-426): extended follow-up from a randomised, open-label, phase 3 trial

Abstract: Summary Background The first interim analysis of the KEYNOTE-426 study showed superior efficacy of pembrolizumab plus axitinib over sunitinib monotherapy in treatment-naive, advanced renal cell carcinoma. The exploratory analysis with extended follow-up reported here aims to assess long-term efficacy and safety of pembrolizumab plus axitinib versus sunitinib monotherapy in patients with advanced renal cell carcinoma. Methods In the ongoing, randomised, open-label, phase 3 KEYNOTE-426 study, adults (≥18 years old) with treatment-naive, advanced renal cell carcinoma with clear cell histology were enrolled in 129 sites (hospitals and cancer centres) across 16 countries. Patients were randomly assigned (1:1) to receive 200 mg pembrolizumab intravenously every 3 weeks for up to 35 cycles plus 5 mg axitinib orally twice daily or 50 mg sunitinib monotherapy orally once daily for 4 weeks per 6-week cycle. Randomisation was done using an interactive voice response system or integrated web response system, and was stratified by International Metastatic Renal Cell Carcinoma Database Consortium risk status and geographical region. Primary endpoints were overall survival and progression-free survival in the intention-to-treat population. Since the primary endpoints were met at the first interim analysis, updated data are reported with nominal p values. This study is registered with ClinicalTrials.gov, NCT02853331. Findings Between Oct 24, 2016, and Jan 24, 2018, 861 patients were randomly assigned to receive pembrolizumab plus axitinib (n=432) or sunitinib monotherapy (n=429). With a median follow-up of 30·6 months (IQR 27·2–34·2), continued clinical benefit was observed with pembrolizumab plus axitinib over sunitinib in terms of overall survival (median not reached with pembrolizumab and axitinib vs 35·7 months [95% CI 33·3–not reached] with sunitinib); hazard ratio [HR] 0·68 [95% CI 0·55–0·85], p=0·0003) and progression-free survival (median 15·4 months [12·7–18·9] vs 11·1 months [9·1–12·5]; 0·71 [0·60–0·84], p Interpretation With extended study follow-up, results from KEYNOTE-426 show that pembrolizumab plus axitinib continues to have superior clinical outcomes over sunitinib. These results continue to support the first-line treatment with pembrolizumab plus axitinib as the standard of care of advanced renal cell carcinoma. Funding Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc.