Deletion of annexin 2 light chain p11 in nociceptors causes deficits in somatosensory coding and pain behavior

The S100 family protein p11 (S100A10, annexin 2 light chain) is involved in the trafficking of the voltage-gated sodium channel Na(V)1.8, TWIK-related acid-sensitive K+ channel (TASK-1), the ligand-gated ion channels acid-sensing ion channel 1a (ASIC1a) and transient receptor potential vanilloid 5/6 (TRPV5/V6), as well as 5-hydroxytryptamine receptor 1B (5-HT1B), a G-protein-coupled receptor. To evaluate the role of p11 in peripheral pain pathways, we generated a loxP-flanked (floxed) p11 mouse and used the Cre-loxP recombinase system to delete p11 exclusively from nociceptive primary sensory neurons in mice. p11-null neurons showed deficits in the expression of NaV1.8, but not of annexin 2. Damage-sensing primary neurons from these animals show a reduced tetrodotoxin-resistant sodium current density, consistent with a loss of membrane-associated NaV1.8. Noxious coding in wide-dynamic-range neurons in the dorsal horn was markedly compromised. Acute pain behavior was attenuated in certain models, but no deficits in inflammatory pain were observed. A significant deficit in neuropathic pain behavior was also apparent in the conditional-null mice. These results confirm an important role for p11 in nociceptor function

Cloning, expression and functional activity of deoxyhypusine synthase from Plasmodium vivax

BACKGROUND: Plasmodium vivax is the most widespread human malaria parasite. However, genetic information about its pathogenesis is limited at present, due to the lack of a reproducible in vitro cultivation method. Sequencing of the Plasmodium vivax genome suggested the presence of a homolog of deoxyhypusine synthase (DHS) from P. falciparum, the key regulatory enzyme in the first committed step of hypusine biosynthesis. DHS is involved in cell proliferation, and thus a valuable drug target for the human malaria parasite P. falciparum. A comparison of the enzymatic properties of the DHS enzymes between the benign and severe Plasmodium species should contribute to our understanding of the differences in pathogenicity and phylogeny of both malaria parasites. RESULTS: We describe the cloning of a 1368 bp putative deoxyhypusine synthase gene (dhs) sequence from genomic DNA of P. vivax PEST strain Salvador I (Accession number AJ549098) after touchdown PCR. The corresponding protein was expressed and functionally characterized as deoxyhypusine synthase by determination of its specific activity and cross-reactivity to human DHS on a Western blot. The putative DHS protein from P. vivax displays a FASTA score of 75 relative to DHS from rodent malaria parasite, P. yoelii, and 74 relative to that from the human parasite, P. falciparum strain 3D7. The ORF encoding 456 amino acids was expressed under control of IPTG-inducible T7 promoter, and expressed as a protein of approximately 50 kDa (theoretically 52.7 kDa) in E. coli BL21 DE3 cells. The N-terminal histidine-tagged protein was purified by Nickel-chelate affinity chromatography under denaturing conditions. DHS with a theoretical pI of 6.0 was present in both eluate fractions. The specific enzymatic activity of DHS was determined as 1268 U/mg protein. The inhibitor, N-guanyl-1, 7-diaminoheptane (GC7), suppressed specific activity by 36-fold. Western blot analysis performed with a polyclonal anti-human DHS antibody revealed cross-reactivity to DHS from P. vivax, despite an amino acid identity of 44% between the proteins. CONCLUSION: We identify a novel DHS protein in the more benign malaria parasite,P. vivax, on the basis of specific enzymatic activity, cross-reactivity with a polyclonal antibody against human DHS, and amino acid identity with DHS homologs from the rodent malaria parasite, P. yoelii, and human P. falciparum strains

C‐reactive protein level as a predictor of difficult emergency laparoscopic cholecystectomy

Background: Studies focused on C‐reactive protein (CRP) as a marker of difficult laparoscopic cholecystectomy are limited to small case series. The aim of this study was to evaluate the association between preoperative CRP concentration and difficulty of laparoscopic cholecystectomy in patients admitted with a biliary emergency presentation. Methods: Patients with an emergency admission for biliary disease treated between 2012 and 2017 with a documented preoperative CRP level were analysed. Elective patients and those with other concurrent causes of increased CRP concentration were excluded. The intraoperative difficulty grade was based on the Nassar scale. Statistical analysis was conducted to determine the association of preoperative CRP level with difficulty grading, adjusted for the interval to surgery. Results: A total of 804 emergency patients were included. The mean preoperative peak CRP level was 64·7 mg/l for operative difficulty grade I, 69·6 mg/l for grade II, 98·2 mg/l for grade III, 217·5 mg/l for grade IV and 193·1 mg/l for grade V, indicating a significant association between CRP concentration and Nassar grade (P < 0·001). Receiver operating characteristic (ROC) curve analysis showed an area under the curve of 0·78 (95 per cent c.i. 0·75 to 0·82), differentiating patients with grade I–III from those with grade IV–V operative difficulty. ROC curve analysis found a cut‐off CRP value of 90 mg/l, with 71·5 per cent sensitivity and 70·5 per cent specificity in predicting operative difficulty of grade IV or V. Logistic regression analysis found preoperative peak CRP level to be predictive of Nassar grade I–III versus grade IV–V operative difficulty, also when adjusted for timing of surgery (odds ratio 5·90, 95 per cent c.i. 2·80 to 12·50). Conclusion: Raised preoperative CRP levels are associated with greater operative difficulty based on Nassar scale grading

Silver diamine fluoride for managing carious lesions:an umbrella review

Background: This umbrella review comprehensively appraised evidence for silver diamine fluoride (SDF) to arrest and prevent root and coronal caries by summarizing systematic reviews. Adverse events were explored. Methods: Following Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, PubMed, Embase, Cochrane Library, PROSPERO register and Joanna Briggs Institute Database of Systematic Reviews were searched for systematic reviews investigating SDF for caries prevention or arrest (1970–2018) without language restrictions. Systematic reviews were selected, data extracted, and risk of bias assessed using ROBIS by two independent reviewers, in duplicate. Corrected covered area was calculated to quantify studies’ overlap across reviews. Results: Eleven systematic reviews were included; four focussing on SDF for root caries in adults and seven on coronal caries in children. These cited 30 studies (4 root caries; 26 coronal caries) appearing 63 times. Five systematic reviews were of “low”, one“unclear” and five “high” risk of bias. Overlap of studies was very high (50% root caries; 17% coronal caries). High overlap and heterogeneity, mainly comparators and outcome measures, precluded meta-analysis. Results were grouped by aim and outcomes to present an overview of direction and magnitude of effect. SDF had a positive effect on prevention and arrest of coronal and root caries, consistently outperforming comparators (fluoride varnish, Atraumatic Restorative Treatment, placebo). For root caries prevention, the prevented fraction (PF) was 25–71% higher for SDF compared to placebo (two systematic reviews with three studies) and PF=100–725% for root caries arrest (one systematic review with two studies). For coronal caries prevention, PF=70–78% (two systematic reviews with two studies) and PF=55–96% for coronal caries arrest (one systematic review with two studies) with arrest rates of 65–91% (four systematic reviews with six studies). Eight systematic reviews reported adverse events, seven of which reported arrested lesions black staining. Conclusion: Systematic reviews consistently supported SDF’s effectiveness for arresting coronal caries in the primary dentition and arresting and preventing root caries in older adults for all comparators. There is insufficient evidence to draw conclusions on SDF for prevention in primary teeth and prevention and arrest in permanent teeth in children. No serious adverse events were reported