Enhanced visibility of hydrogen atoms by neutron crystallography on fully deuterated myoglobin

Although hydrogens comprise half of the atoms in a protein molecule and are of great importance chemically and structurally, direct visualization of them by using crystallography is difficult. Neutron crystallography is capable of directly revealing the position of hydrogens, but its use on unlabeled samples faces certain technical difficulties: the large incoherent scattering of hydrogen results in background scattering that greatly reduces the signal to noise of the experiment. Moreover, whereas the scattering lengths of C, N, and O are positive, that of hydrogen is negative and about half the magnitude. This results in density for hydrogens being half as strong and close to the threshold of detection at 2.0-A resolution. Also, because of its opposite sign, there is a partial cancellation of the hydrogen density with that from neighboring atoms, which can lead to ambiguities in interpretation at medium resolution. These difficulties can be overcome by the use of deuterated protein, and we present here a neutron structure of fully deuterated myoglobin. The structure reveals a wealth of chemical information about the molecule, including the geometry of hydrogen bonding, states of protonation of histidines, and the location and geometry of water molecules at the surface of the protein. The structure also should be of broader interest because it will serve as a benchmark for molecular dynamics and energy minimization calculations and for comparison with NMR studies.     

Circulating lipoprotein profiles are modulated differently by lipoprotein lipase in obese humans

BACKGROUND: Several genetic analyses have suggested that lipoprotein lipase (LpL) genotypes causing decreased LpL activity correlate with increased triglyceride concentrations and risk for coronary artery disease. In contrast, in some other studies LpL activity was positively correlated with plasma low-density lipoprotein (LDL) cholesterol concentrations. OBJECTIVE: To assess whether these different associations represent physiologic differences in lipoprotein metabolism. METHODS: We correlated postheparin lipase activities, postprandial lipemia, and fasting lipoprotein concentrations in obese (BMI > or = 30 kg/m2, n = 26) and non-obese (BMI < or = 30 kg/m2, n = 57) individuals. LpL was measured using specific inhibitory antibodies. RESULTS: Surprisingly, LpL activity was significantly correlated with triglyceride area under the curve after a fat load in the non-obese, but not the entire group. Moreover, in non-obese individuals, LpL activity correlated directly (r = 0.40) and hepatic lipase activity correlated inversely (r = -0.32) with high-density lipoprotein (HDL) cholesterol concentrations. These relationships were not found in the obese group, in whom LpL correlated with LDL cholesterol concentrations (r = 0.54). CONCLUSIONS: We conclude that postheparin LpL activity relates to different lipoproteins in obese and non-obese individuals. In obesity, greater LpL activity may enhance conversion of very-low-density lipoprotein cholesterol to LDL cholesterol, whereas in non-obese individuals the correlation is with HDL cholesterol. Whether this is due to differences in the source of LpL (muscle or fat), or to other associated alterations in lipoprotein metabolism is unknown. These results may explain the non-uniformity of correlations between LpL and atherogenic lipoproteins in different populations.     

A randomized controlled trial to evaluate the slow-acting symptom-modifying effects of colchicine in osteoarthritis of the knee: a preliminary report

OBJECTIVE: To determine if colchicine added to nimesulide may have a beneficial effect on osteoarthritis (OA) of the knee.METHODS: Colchicine 0.5 mg twice daily or placebo was added to nimesulide (a nonsteroidal antiinflammatory drug) in 36 patients with OA of the knee in a randomized, double-blind, placebo-controlled trial over a 5-month period.RESULTS: The 30% improvement rate at 20 weeks was higher in the colchicine group than in the control group receiving placebo, as measured by total Western Ontario and McMaster University Osteoarthritis scores (57.9% versus 23.5%) and visual analog scale for index knee pain (52.6% versus 17.6%) (primary measures of response). The significance persisted on combined analysis by Mantel-Haenszel test (P = 0.062). Comparison of means also showed significant improvement in the colchicine group versus the control group in a multivariate analysis performed using T(2) test (P = 0.0115).CONCLUSION: Among patients with OA of the knee, the group receiving colchicine plus nimesulide exhibited significantly greater symptomatic benefit at 20 weeks than did the control group receiving nimesulide plus placebo.     

A comparison of epinephrine and norepinephrine in critically ill patients

Objective  To determine whether there was a difference between epinephrine and norepinephrine in achieving a mean arterial pressure (MAP) goal in intensive care (ICU) patients. Design  Prospective, double-blind, randomised-controlled trial. Setting  Four Australian university-affiliated multidisciplinary ICUs. Patients and participants  Patients who required vasopressors for any cause at randomisation. Patients with septic shock and acute circulatory failure were analysed separately. Interventions  Blinded infusions of epinephrine or norepinephrine to achieve a MAP ≥70 mmHg for the duration of ICU admission. Measurements  Primary outcome was achievement of MAP goal >24 h without vasopressors. Secondary outcomes were 28 and 90-day mortality. Two hundred and eighty patients were randomised to receive either epinephrine or norepinephrine. Median time to achieve the MAP goal was 35.1 h (interquartile range (IQR) 13.8–70.4 h) with epinephrine compared to 40.0 h (IQR 14.5–120 h) with norepinephrine (relative risk (RR) 0.88; 95% confidence interval (CI) 0.69–1.12; P = 0.26). There was no difference in the time to achieve MAP goals in the subgroups of patients with severe sepsis (n = 158; RR 0.81; 95% CI 0.59–1.12; P = 0.18) or those with acute circulatory failure (n = 192; RR 0.89; 95% CI 0.62–1.27; P = 0.49) between epinephrine and norepinephrine. Epinephrine was associated with the development of significant but transient metabolic effects that prompted the withdrawal of 18/139 (12.9%) patients from the study by attending clinicians. There was no difference in 28 and 90-day mortality. Conclusions  Despite the development of potential drug-related effects with epinephrine, there was no difference in the achievement of a MAP goal between epinephrine and norepinephrine in a heterogenous population of ICU patients. This study was presented at the Annual Congress of the European Society of Intensive Care Medicine in Berlin on October 10 2007. The presentation received the International Sepsis Forum prize for best abstract and paper. This study has been published in abstract form: Myburgh J.A., Higgins A., Jovanovska A., Lipman J., Ramakrishnan N., Santamaria J and the CAT Study Investigators. (2007). A comparison of epinephrine and norepinephrine on reversal of shock. Intensive Care Medicine 33 (Supplement 2): S197. Trial registration: The study was registered with Current Controlled Studies: ISRCTN number 92846592.     

Hesperidin attenuates mitochondrial dysfunction during benzo(a)pyrene‐induced lung carcinogenesis in mice

The present study is designed to assess the mitochondrial status during benzo(a)pyrene (B(a)P)‐induced lung carcinogenesis in Swiss albino mice and to reveal the modulatory effect of hesperidin over it. B(a)P (50 mg/kg body weight)‐induced mitochondrial abnormalities was evident from alterations in mitochondrial lipid peroxides, antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione‐S‐transferase, reduced glutathione, vitamin E, and vitamin C), major tricarboxylic acid (TCA) cycle enzyme activities (isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, alpha‐ketoglutarate dehydrogenase), electron transport chain (ETC) complexes activities and ATP levels. Ultrastructural changes in lung mitochondria were also in accord with the above aberrations. Hesperidin (25 mg/kg body weight) supplementation effectively counteracted all the above changes and restored cellular normalcy, indicating its protective role during B(a)P‐induced lung cancer.     

Non-pharmacological management of phantom limb pain in lower limb amputation: a systematic review

Background: The incidence and severity of phantom limb pain (PLP) does not differ much between the extremities of amputation. However, its impact on functional ability and quality of life in lower limb amputation may be different, as prosthetic weight bearing is a key component in the movement and functional rehabilitation of individuals with a lower limb amputation.

Objective: To evaluate the evidence for effectiveness or efficacy of non-pharmacological interventions in the management of PLP in adults with lower limb amputation.

Methods: A comprehensive literature search conducted on 11 electronic databases, from their inception to 25 March 2016 identified 626 potentially relevant articles. Full-text randomised controlled trials in English which examined any form of non-pharmacologic intervention for managing PLP in lower limb amputees were included. The data with regard to characteristics of the studies, participants, intervention and outcome measures and overall statistical result were extracted. The Cochrane ‘Risk of bias assessment tool’ was used to assess the bias of all included articles.

Results: Four studies met the final criteria to be included in the review. Four treatment techniques had been used in the treatment of 204 patients with lower limb amputation. Two trials showed a positive impact of intervention on PLP compared to control group. Risk of bias varied across studies, and only one included study was assessed as having a low risk of bias.

Conclusion: The review identified lack of evidence to support non-pharmacological interventions in the management of PLP. Adequately powered high-quality trials are needed in this area to inform rehabilitation.     

Atherosclerosis in Asian Indians with systemic lupus erythematosus

OBJECTIVES: Atherosclerosis has emerged as an important late complication of systemic lupus erythematosus (SLE). Asian Indians, as an ethnic group, are known to be metabolically predisposed to development of early atherosclerosis. No data on this aspect of SLE are available from Asia. This study was undertaken to find the frequency of atherosclerosis in Indian lupus patients and the factors affecting such an occurrence. METHODS: Carotid artery intimo-medial thickness (IMT) and plaque were used as markers of atherosclerosis. High-resolution B-mode ultrasonography was used to compare carotid IMT and plaque in 50 patients with SLE and 50 age- and sex-matched healthy controls. RESULTS: Patients with lupus (age 31.6+/-10.05, median 30.5 years; disease duration 52.3+/-36.7, median 46 months) exhibited a significantly greater IMT than controls (0.417+/-0.07 vs. 0.362+/-00.07 mm; p = 0.003). Carotid plaques were seen in seven (14%) cases. None of the control population had plaques (p = 0.006). On bivariate analysis, the IMT was significantly affected by age, systolic blood pressure (SBP), disease duration and menopausal status. On multivariate analysis, the only factor significantly affecting IMT was SBP. The Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) score was the sole factor found to significantly affect the occurrence of plaque. CONCLUSIONS: Asian Indian lupus patients in our study, despite being relatively young and with shorter disease duration, exhibited premature atherosclerosis in the form of significantly thicker intimo-media and plaque. The factors found to affect accelerated atherosclerosis in our cohort were age, SBP, disease duration, postmenopausal status and the SLICC/ACR score.     

The apolipoprotein(a) gene: linkage disequilibria at three loci differs in African Americans and Caucasians

Lipoprotein(a) (Lp(a)) is an independent, genetically regulated cardiovascular risk factor. Lp(a) plasma levels are largely determined by the apolipoprotein(a) (apo(a)) component, and differ across ethnicity. Although a number of polymorphisms in the apo(a) gene have been identified, apo(a) genetic regulation is not fully understood. To study the relation between apo(a) gene variants, we constructed haplotypes and assessed linkage equilibrium in African Americans and Caucasians for three widely studied apo(a) gene polymorphisms (apo(a) size, +93 C/T and pentanucleotide repeat region (PNR)). Apo(a) size allele frequency distributions were different across ethnicity (p<0.01). For African Americans, PNR frequencies were similar across apo(a) sizes, suggesting linkage equilibrium. For Caucasians, the PNR and the PNR-C/T haplotype frequencies differed for large and small apo(a), with the T and PNR 9 alleles associated with large apo(a) size (p<0.0002); also, the PNR 9 allele was more common on a T allele, while PNR 8 was more common on a C allele. On a C allele background, small PNR alleles were more common and the PNR 10 allele less common among African Americans than Caucasians (p<0.001). The ethnic difference in apo(a) size distribution remained controlling for C/T and PNR alleles (p=0.023). In conclusion, allele and haplotype frequencies and the nature of the linkage disequilibrium differed between African Americans and Caucasians at three apo(a) gene polymorphisms.     

A randomized controlled trial to evaluate the slow‐acting symptom‐modifying effects of colchicine in osteoarthritis of the knee: A preliminary report

Objective

To determine if colchicine added to nimesulide may have a beneficial effect on osteoarthritis (OA) of the knee.

Methods

Colchicine 0.5 mg twice daily or placebo was added to nimesulide (a nonsteroidal antiinflammatory drug) in 36 patients with OA of the knee in a randomized, double‐blind, placebo‐controlled trial over a 5‐month period.

Results

The 30% improvement rate at 20 weeks was higher in the colchicine group than in the control group receiving placebo, as measured by total Western Ontario and McMaster University Osteoarthritis scores (57.9% versus 23.5%) and visual analog scale for index knee pain (52.6% versus 17.6%) (primary measures of response). The significance persisted on combined analysis by Mantel‐Haenszel test (P = 0.062). Comparison of means also showed significant improvement in the colchicine group versus the control group in a multivariate analysis performed using T² test (P = 0.0115).

Conclusion

Among patients with OA of the knee, the group receiving colchicine plus nimesulide exhibited significantly greater symptomatic benefit at 20 weeks than did the control group receiving nimesulide plus placebo.