Naturally occurring variations in the human cholinesterase genes: heritability and association with cardiovascular and metabolic traits

Cholinergic neurotransmission in the central and autonomic nervous systems regulates immediate variations in and longer-term maintenance of cardiovascular function with acetylcholinesterase (AChE) activity that is critical to temporal responsiveness. Butyrylcholinesterase (BChE), largely confined to the liver and plasma, subserves metabolic functions. AChE and BChE are found in hematopoietic cells and plasma, enabling one to correlate enzyme levels in whole blood with hereditary traits in twins. Using both twin and unrelated subjects, we found certain single nucleotide polymorphisms (SNPs) in the ACHE gene correlated with catalytic properties and general cardiovascular functions. SNP discovery from ACHE resequencing identified 19 SNPs: 7 coding SNPs (cSNPs), of which 4 are nonsynonymous, and 12 SNPs in untranslated regions, of which 3 are in a conserved sequence of an upstream intron. Both AChE and BChE activity traits in blood were heritable: AChE at 48.8 ± 6.1% and BChE at 81.4 ± 2.8%. Allelic and haplotype variations in the ACHE and BCHE genes were associated with changes in blood AChE and BChE activities. AChE activity was associated with BP status and SBP, whereas BChE activity was associated with features of the metabolic syndrome (especially body weight and BMI). Gene products from cDNAs with nonsynonymous cSNPs were expressed and purified. Protein expression of ACHE nonsynonymous variant D134H (SNP6) is impaired: this variant shows compromised stability and altered rates of organophosphate inhibition and oxime-assisted reactivation. A substantial fraction of the D134H instability could be reversed in the D134H/R136Q mutant. Hence, common genetic variations at ACHE and BCHE loci were associated with changes in corresponding enzymatic activities in blood.     

Portal Hypertension and an Atypical Reactive Arthritis Like Presentation in a patient infected with Hepatitis C Virus Genotype 3

Background:Reactive arthritis (ReA) is defined as a peripheral arthritis lasting longer than 1 month, associated with urethritis, cervicitis, or diarrhea. The reported annual incidence of ReA is approximately 30-40 cases per 100,000 adults, occurring commonly in the age group of 16 and 35 years. It is known to be associated with gastrointestinal infections with Shigella, Salmonella, and Campylobacter species and other microorganisms, as well as with genitourinary infections (especially with Chlamydia trachomatis).Conclusions:Our case is unlike classical ReA because the patient is older, HLA B27 negative, and without florid urethritis. Admitted for fever and lower urinary tract symptoms, along with respiratory distress, the primary objective of the emergency doctors was to prevent the patient from progressing to organ failure. The diagnosis of underlying atypical/incomplete ReA could easily have been missed without adequate awareness, dermatological consultation, and a skin biopsy.     

Surface cross‐linked UHMWPE can enable the use of larger femoral heads in total joints

Limiting cross‐linking to the articular surfaces of ultrahigh molecular weight polyethylene (UHMWPE) to increase wear resistance while preventing detrimental effects of cross‐linking on mechanical strength has been a desirable goal. A surface cross‐linked UHMWPE can be achieved by blending UHMWPE with a free radical scavenger, such as vitamin E, consolidating the blend into an implant shape, extracting the vitamin E from the surface, and radiation cross‐linking the surface extracted blend. This process results in high cross‐link density in the vitamin E‐depleted surface region because vitamin E hinders cross‐linking during irradiation. In this study, we described the properties of successful extraction media and the manipulation of the wear and mechanical properties of extracted, irradiated blends. We showed that these formulations could have similar wear and significantly improved mechanical properties compared to currently available highly cross‐linked UHMWPEs. We believe that these materials can enable thinner implant forms and more anatomical designs in joint arthroplasty and may provide a feasible alternative to metal‐on‐metal implants. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:59–66, 2012     

Phase 1 Randomized,Double-Blind,Placebo-Controlled Study of RG7667, an Anticytomegalovirus Combination Monoclonal Antibody Therapy,in Healthy Adults

Cytomegalovirus can cause debilitating and life-threatening disease in newborns infected in utero and immunocompromised individuals, including transplant recipients. RG7667 is a unique combination of two monoclonal antibodies that binds glycoprotein complexes on the surface of cytomegalovirus and inhibits its entry into host cells. A phase 1 first-in-human, randomized, double-blind, placebo-controlled, dose-escalation study of RG7667 given intravenously was conducted in 181 healthy adults. The study involved a single ascending dose stage (1, 3, 5, and 10 mg/kg each antibody; n = 21), a multiple ascending dose stage (5 and 10 mg/kg each antibody monthly for 3 doses; n = 10), and a multiple dose expansion stage (10 mg/kg each antibody monthly for 3 doses; n = 150). Subjects were followed for 85 to 141 days to evaluate safety, tolerability, pharmacokinetics, and immunogenicity. Most adverse events were mild, and the incidence of adverse events was similar among the RG7667 and placebo groups. RG7667 had dose-proportional pharmacokinetics in all three dosing stages, a mean terminal half-life of 20 to 30 days, and an overall pharmacokinetic profile consistent with that of a human monoclonal antibody that lacks endogenous host targets. The proportion of subjects developing an antitherapeutic antibody response was not higher in the RG7667 group than in the placebo group. In summary, single and multiple doses of RG7667 were found to be safe and well-tolerated in healthy adults and had a favorable pharmacokinetic and immunogenicity profile. This study supports further development of RG7667 as a therapy for the prevention and treatment of cytomegalovirus infection in susceptible populations. (This study has been registered at ClinicalTrials.gov under registration no. {"type":"clinical-trial","attrs":{"text":"NCT01496755","term_id":"NCT01496755"}}NCT01496755.)     

Classic Kaposi's sarcoma presenting first with gastrointestinal tract involvement in a HIV-negative Inuit male--a case report and review of the literature

Kaposi's sarcoma (KS) is a multicentric low-grade vascular malignancy. In North America, it is usually seen in AIDS and solid organ transplant populations. Classic KS is a subtype that traditionally occurs in elderly HIV-negative males of Mediterranean, Eastern European, and Jewish descent. Patients with classic KS characteristically present with skin lesions in the distal extremities. Involvement of the viscera is uncommon in classic KS, but may occur in the late stages of the disease. We report the first case of classic KS presenting in the gastrointestinal tract of an elderly HIV-negative Inuit male from Northern Quebec, Canada.     

Genetic variation at the human alpha2B-adrenergic receptor locus: role in blood pressure variation and yohimbine response

Exaggerated response to alpha2-adrenergic receptor (alpha2-AR) blockade by yohimbine in normotensive subjects is an intermediate phenotype that predicts increased risk for development of hypertension. Here, we assessed the 3 alpha2-AR loci (alpha2A, alpha2B, alpha2C) as candidate genes for their influence on baseline and yohimbine-mediated increase in mean arterial pressure. Because initial results with 173 individuals implicated a possible association of yohimbine response with genetic variation at a site in the alpha2B-AR gene, but not at sites in the other 2 alpha2-AR, we sequenced the alpha2B-AR gene (4.4 kb, including 1.2 kb upstream and 1.9 kb distal to the coding sequence) in those subjects and an additional 81 individuals to search for other alpha2B-AR variants. We identified 25 polymorphisms, of which 14 are previously unreported, and 2 major haplotypes that differ by the presence/absence of a 9-bp in-frame deletion that encodes Glu301 to Glu303. Frequency differences in haplotypes were observed between blacks and whites but did not predict response to yohimbine. Genotyping of 2 additional white cohorts, including 1269 individuals with extremes in blood pressure selected from >50,000 subjects, also failed to reveal an association of the 2 major alpha2B-AR haplotypes with differences in blood pressure. Thus, despite considerable polymorphism in alpha2-AR genes, such variation is not a major determinant of variability in yohimbine response and by inference, in susceptibility to essential hypertension.