Role of pH in determining the cell-type-specific residual activity of glucocerebrosidase in type 1 Gaucher disease.

The properties of control and 370Asn-->Ser glucocerebrosidase, the frequently encountered mutated form of the enzyme in type 1 Gaucher disease, were studied in vitro as well as in situ. The catalytic properties of purified 370Asn-->Ser glucocerebrosidase were highly dependent on the assay conditions. The enzyme was deficient in activity towards substrate and in reactivity with the irreversible inhibitor conduritol B-epoxide (CBE) when activated by the bile salt taurocholate. In the presence of more physiological activators, the lysosomal activator protein saposin C and phosphatidylserine, the 370Asn-->Ser enzyme was near normal in kinetic properties at pH values approximately 5, but not at higher pH. In intact fibroblasts, the enzymic activity of the 370Asn-->Ser glucocerebrosidase and its reactivity with CBE were found to be clearly deficient. However, in intact lymphoblasts from the same patients, the behavior of the mutant enzyme was near normal. The catalytic efficiency of 370Asn-->Ser glucocerebrosidase in situ was also found to be highly pH dependent. When intact lymphoblasts were cultured in the presence of permeant weak bases, which increase the pH of acidic intracellular compartments, the catalytic efficiency of the mutant enzyme, as assessed by its reactivity with CBE, became markedly impaired. Our findings indicate that the intralysosomal pH in the intact cell can be expected to have a critical influence on the activation state of 370Asn-->Ser glucocerebrosidase and its ability to hydrolyse substrate. This phenomenon may partly underly the marked heterogeneity in clinical manifestation of Gaucher disease among patients with this mutated form of glucocerebrosidase.FWN – Publicaties zonder aanstelling Universiteit Leide

The generation and utilization of a cancer-oriented representation of the human transcriptome by using expressed sequence tags.

Whereas genome sequencing defines the genetic potential of an organism, transcript sequencing defines the utilization of this potential and links the genome with most areas of biology. To exploit the information within the human genome in the fight against cancer, we have deposited some two million expressed sequence tags (ESTs) from human tumors and their corresponding normal tissues in the public databases. The data currently define approximately 23,500 genes, of which only approximately 1,250 are still represented only by ESTs. Examination of the EST coverage of known cancer-related (CR) genes reveals that <1% do not have corresponding ESTs, indicating that the representation of genes associated with commonly studied tumors is high. The careful recording of the origin of all ESTs we have produced has enabled detailed definition of where the genes they represent are expressed in the human body. More than 100,000 ESTs are available for seven tissues, indicating a surprising variability of gene usage that has led to the discovery of a significant number of genes with restricted expression, and that may thus be therapeutically useful. The ESTs also reveal novel nonsynonymous germline variants (although the one-pass nature of the data necessitates careful validation) and many alternatively spliced transcripts. Although widely exploited by the scientific community, vindicating our totally open source policy, the EST data generated still provide extensive information that remains to be systematically explored, and that may further facilitate progress toward both the understanding and treatment of human cancers

Safety and efficacy of non-steroidal anti-inflammatory drugs to reduce ileus after colorectal surgery

Background: Ileus is common after elective colorectal surgery, and is associated with increased adverse events and prolonged hospital stay. The aim was to assess the role of non-steroidal anti-inflammatory drugs (NSAIDs) for reducing ileus after surgery. Methods: A prospective multicentre cohort study was delivered by an international, student- and trainee-led collaborative group. Adult patients undergoing elective colorectal resection between January and April 2018 were included. The primary outcome was time to gastrointestinal recovery, measured using a composite measure of bowel function and tolerance to oral intake. The impact of NSAIDs was explored using Cox regression analyses, including the results of a centre-specific survey of compliance to enhanced recovery principles. Secondary safety outcomes included anastomotic leak rate and acute kidney injury. Results: A total of 4164 patients were included, with a median age of 68 (i.q.r. 57\u201375) years (54\ub79 per cent men). Some 1153 (27\ub77 per cent) received NSAIDs on postoperative days 1\u20133, of whom 1061 (92\ub70 per cent) received non-selective cyclo-oxygenase inhibitors. After adjustment for baseline differences, the mean time to gastrointestinal recovery did not differ significantly between patients who received NSAIDs and those who did not (4\ub76 versus 4\ub78 days; hazard ratio 1\ub704, 95 per cent c.i. 0\ub796 to 1\ub712; P = 0\ub7360). There were no significant differences in anastomotic leak rate (5\ub74 versus 4\ub76 per cent; P = 0\ub7349) or acute kidney injury (14\ub73 versus 13\ub78 per cent; P = 0\ub7666) between the groups. Significantly fewer patients receiving NSAIDs required strong opioid analgesia (35\ub73 versus 56\ub77 per cent; P < 0\ub7001). Conclusion: NSAIDs did not reduce the time for gastrointestinal recovery after colorectal surgery, but they were safe and associated with reduced postoperative opioid requirement