Peak plasma interleukin-6 and other peripheral markers of inflammation in the first week of ischaemic stroke correlate with brain infarct volume, stroke severity and long-term outcome

Background

Cerebral ischaemia initiates an inflammatory response in the brain and periphery. We assessed the relationship between peak values of plasma interleukin-6 (IL-6) in the first week after ischaemic stroke, with measures of stroke severity and outcome.

Methods

Thirty-seven patients with ischaemic stroke were prospectively recruited. Plasma IL-6, and other markers of peripheral inflammation, were measured at pre-determined timepoints in the first week after stroke onset. Primary analyses were the association between peak plasma IL-6 concentration with both modified Rankin score (mRS) at 3 months and computed tomography (CT) brain infarct volume.

Results

Peak plasma IL-6 concentration correlated significantly (p < 0.001) with CT brain infarct volume (r = 0.75) and mRS at 3 months (r = 0.72). It correlated similarly with clinical outcome at 12 months or stroke severity. Strong associations were also noted between either peak plasma C-reactive protein (CRP) concentration or white blood cell (WBC) count, and all outcome measures.

Conclusions

These data provide evidence that the magnitude of the peripheral inflammatory response is related to the severity of acute ischaemic stroke, and clinical outcome.     

Palmitoylation regulates regulator of G-protein signaling (RGS) 16 function. II. Palmitoylation of a cysteine residue in the RGS box is critical for RGS16 GTPase accelerating activity and regulation of Gi-coupled signalling

Palmitoylation is a reversible post-translational modification used by cells to regulate protein activity. The regulator of G-protein signaling (RGS) proteins RGS4 and RGS16 share conserved cysteine (Cys) residues that undergo palmitoylation. In the accompanying article (Hiol, A., Davey, P. C., Osterhout, J. L., Waheed, A. A., Fischer, E. R., Chen, C. K., Milligan, G., Druey, K. M., and Jones, T. L. Z. (2003) J. Biol. Chem. 278, 19301-19308), we determined that mutation of NH2-terminal cysteine residues in RGS16 (Cys-2 and Cys-12) reduced GTPase accelerating (GAP) activity toward a 5-hydroxytryptamine (5-HT1A)/G alpha o1 receptor fusion protein in cell membranes. NH2-terminal acylation also permitted palmitoylation of a cysteine residue in the RGS box of RGS16 (Cys-98). Here we investigated the role of internal palmitoylation in RGS16 localization and GAP activity. Mutation of RGS16 Cys-98 or RGS4 Cys-95 to alanine reduced GAP activity on the 5-HT1A/G alpha o1 fusion protein and regulation of adenylyl cyclase inhibition. The C98A mutation had no effect on RGS16 localization or GAP activity toward purified G-protein alpha subunits. Enzymatic palmitoylation of RGS16 resulted in internal palmitoylation on residue Cys-98. Palmitoylated RGS16 or RGS4 WT but not C98A or C95A preincubated with membranes expressing 5-HT1a/G alpha o1 displayed increased GAP activity over time. These results suggest that palmitoylation of a Cys residue in the RGS box is critical for RGS16 and RGS4 GAP activity and their ability to regulate Gi-coupled signaling in mammalian cells.     

Palmitoylation regulates regulators of G-protein signaling (RGS) 16 function. I. Mutation of amino-terminal cysteine residues on RGS16 prevents its targeting to lipid rafts and palmitoylation of an internal cysteine residue

Regulators of G-protein signaling (RGS) proteins down-regulate signaling by heterotrimeric G-proteins by accelerating GTP hydrolysis on the G alpha subunits. Palmitoylation, the reversible addition of palmitate to cysteine residues, occurs on several RGS proteins and is critical for their activity. For RGS16, mutation of Cys-2 and Cys-12 blocks its incorporation of [3H]palmitate and ability to turn-off Gi and Gq signaling and significantly inhibited its GTPase activating protein activity toward aG alpha subunit fused to the 5-hydroxytryptamine receptor 1A, but did not reduce its plasma membrane localization based on cell fractionation studies and immunoelectron microscopy. Palmitoylation can target proteins, including many signaling proteins, to membrane microdomains, called lipid rafts. A subpopulation of endogenous RGS16 in rat liver membranes and overexpressed RGS16 in COS cells, but not the nonpalmitoylated cysteine mutant of RGS16, localized to lipid rafts. However, disruption of lipid rafts by treatment with methyl-beta-cyclodextrin did not decrease the GTPase activating protein activity of RGS16. The lipid raft fractions were enriched in protein acyltransferase activity, and RGS16 incorporated [3H]palmitate into a peptide fragment containing Cys-98, a highly conserved cysteine within the RGS box. These results suggest that the amino-terminal palmitoylation of an RGS protein promotes its lipid raft targeting that allows palmitoylation of a poorly accessible cysteine residue that we show in the accompanying article (Osterhout, J. L., Waheed, A. A., Hiol, A., Ward, R. J., Davey, P. C., Nini, L., Wang, J., Milligan, G., Jones, T. L. Z., and Druey, K. M. (2003) J. Biol. Chem. 278, 19309-19316) was critical for RGS16 and RGS4 GAP activity.     

A de novo designed helix-turn-helix peptide forms nontoxic amyloid fibrils

We report here that a monomeric de novo designed alpha-helix-turn-alpha-helix peptide, alpha t alpha, when incubated at 37 degrees C in an aqueous buffer at neutral pH, forms nonbranching, protease resistant fibrils that are 6-10 nm in diameter. These fibrils are rich in beta-sheet and bind the amyloidophilic dye Congo red. alpha t alpha fibrils thus display the morphologic, structural, and tinctorial properties of authentic amyloid fibrils. Surprisingly, unlike fibrils formed by peptides such as the amyloid beta-protein or the islet amyloid polypeptide, alpha t alpha fibrils were not toxic to cultured rat primary cortical neurons or PC12 cells. These results suggest that the potential to form fibrils under physiologic conditions is not limited to those proteins associated with amyloidoses and that fibril formation alone is not predictive of cytotoxic activity.     

1H NMR metabolomics reveals increased glutaminolysis upon overexpression of NSD3s or Pdp3 in Saccharomyces cerevisiae

NSD3s, the proline-tryptophan-tryptophan-proline (PWWP) domain-containing, short isoform of the human oncoprotein NSD3, displays high transforming properties. Overexpression of human NSD3s or the yeast protein Pdp3 in Saccharomyces cerevisiae induces similar metabolic changes, including increased growth rate and sensitivity to oxidative stress, accompanied by decreased oxygen consumption. Here, we set out to elucidate the biochemical pathways leading to the observed metabolic phenotype by analyzing the alterations in yeast metabolome in response to NSD3s or Pdp3 overexpression using ¹H nuclear magnetic resonance (NMR) metabolomics. We observed an increase in aspartate and alanine, together with a decrease in arginine levels, on overexpression of NSD3s or Pdp3, suggesting an increase in the rate of glutaminolysis. In addition, certain metabolites, including glutamate, valine, and phosphocholine were either NSD3s or Pdp3 specific, indicating that additional metabolic pathways are adapted in a protein-dependent manner. The observation that certain metabolic pathways are differentially regulated by NSD3s and Pdp3 suggests that, despite the structural similarity between their PWWP domains, the two proteins act by unique mechanisms and may recruit different downstream signaling complexes. This study establishes for the first time a functional link between the human oncoprotein NSD3s and cancer metabolic reprogramming.     

Full-genome sequences of hepatitis B virus subgenotype D3 isolates from the Brazilian Amazon Region

The Brazilian Amazon Region is a highly endemic area for hepatitis B virus (HBV). However, little is known regarding the genetic variability of the strains circulating in this geographical region. Here, we describe the first full-length genomes of HBV isolated in the Brazilian Amazon Region; these genomes are also the first complete HBV subgenotype D3 genomes reported for Brazil. The genomes of the five Brazilian isolates were all 3,182 base pairs in length and the isolates were classified as belonging to subgenotype D3, subtypes ayw2 (n = 3) and ayw3 (n = 2). Phylogenetic analysis suggested that the Brazilian sequences are not likely to be closely related to European D3 sequences. Such results will contribute to further epidemiological and evolutionary studies of HBV.     

A preliminary investigation into the relationship between functional movement screen scores and athletic physical performance in female team sport athletes

There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearman''s correlations (p ≤ 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p ≤ 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes.     

The 4Kscore? Test Reduces Prostate Biopsy Rates in Community and Academic Urology Practices

There is significant concern regarding prostate cancer screening because of the potential for overdiagnosis and overtreatment of men who are discovered to have abnormal prostate specific antigen (PSA) levels and/or digital rectal examination (DRE) results. The 4Kscore® Test (OPKO Diagnostics, LLC) is a blood test that utilizes four kallikrein levels plus clinical information in an algorithm to calculate an individual’s percentage risk (< 1% to > 95%) for aggressive prostate cancer (Gleason score ≥ 7) on prostate biopsy. The 4Kscore Test, as a follow-up test after abnormal PSA and/or DRE test results, has been shown to improve the specificity for predicting the risk of aggressive prostate cancer and reduce unnecessary prostate biopsies. A clinical utility study was conducted to assess the influence of the 4Kscore Test on the decision to perform prostate biopsies in men referred to urologists for abnormal PSA and/or DRE results. The study population included 611 patients seen by 35 academic and community urologists in the United States. Urologists ordered the 4Kscore Test as part of their assessment of men referred for abnormal PSA and/or DRE test results. Results for the patients were stratified into low risk (< 7.5%), intermediate risk (7.5%–19.9%), and high risk (≥ 20%) for aggressive prostate cancer. The 4Kscore Test results influenced biopsy decisions in 88.7% of the men. Performing the 4Kscore Test resulted in a 64.6% reduction in prostate biopsies in patients; the actual percentage of cases not proceeding to biopsy were 94.0%, 52.9%, and 19.0% for men who had low-, intermediate-, and high-risk 4Kscore Test results, respectively. A higher 4Kscore Test was associated with greater likelihood of having a prostate biopsy (P < 0.001). Among the 171 patients who had a biopsy, the 4Kscore risk category is strongly associated with biopsy pathology. The 4Kscore Test, as a follow-up test for an abnormal PSA and/or DRE results, significantly influenced the physician and patient shared decision in clinical practice, which led to a reduction in prostate biopsies while increasing the probability of detecting aggressive cancer.Key Words: Prostate cancer, Prostate-specific antigen, Digital rectal examination, Biopsy rate, Gleason score, 4Kscore Test, Prostate cancer prognosisWidespread screening for prostate cancer with serum prostate-specific antigen (PSA) began in 1991, and subsequently a 45% decline in prostate cancer mortality has been observed.¹ A recent large European randomized clinical trial also reported a 29% reduction in death from prostate cancer in men undergoing routine screening.² However, because of a US study that showed no mortality benefits to organized PSA screening,³ and the net physical and psychologic burden of secondary adverse events triggered by PSA testing versus the number of lives saved, the United States Preventative Services Task Force (USPSTF) recently advised against routine PSA screening for prostate cancer.⁴ The concern of the USPSTF is based on the fact that most men diagnosed with prostate cancer have a tumor that is unlikely to pose a threat to life expectancy. A recent systematic analysis suggested that up to 60% of prostate cancers diagnosed in contemporary studies might be safely observed without a need for immediate intervention.⁵One of the primary challenges for urologists is the potential for under-grading of Gleason 6 prostate cancer due to biopsy sampling error; as a result, up to 90% of men with a Gleason 6 prostate cancer still proceed to prostate cancer treatment despite the advent of active surveillance programs. Approximately 66% of patients who are diagnosed with Gleason 6 disease at biopsy will be confirmed to have Gleason 6 cancer after radical prostatectomy.⁶ Some of these men are considered to have undergone overtreatment, because Gleason 6 cancer is not considered life threatening.⁷ This subset of men has the potential for developing complications following surgery, including erectile dysfunction, urinary incontinence, and changes in health-related quality of life with disruption of psychologic, sexual, and urinary function.^8–12The prostate biopsy procedure is invasive, and has significant costs and complications such as bleeding, urinary retention, and life-threatening infection. A recent population-based study from Ontario, Canada, revealed a fourfold increase to 4.1% for the rate of hospital admissions after prostate biopsy from 1996 to 2005, with 72% of admissions due to infection.¹³ These risks, combined with the anxiety involved in undergoing the procedure, present a significant burden to any man considering prostate cancer screening.The impact of the USPSTF has been a decrease in overall biopsy rates with a subsequent decline in the detection rate of Gleason 7 to 10 high-grade prostate cancers.¹⁴ The elimination of PSA screening means that the 20% to 30% of men who would have presented with an abnormal PSA level and been found to have high-grade prostate cancer may lose an opportunity for a possible cure.¹⁵ Clearly, there is a need for better risk-stratification tools for men presenting with an abnormal PSA level and/or digital rectal examination (DRE) result in order to both reduce the number of prostate biopsies performed and decrease the rate of Gleason 6 diagnosis and treatment.⁶The 4Kscore® Test (OPKO Diagnostics, LLC) incorporates measured blood levels of four kallikrein proteins: total PSA, free PSA, intact PSA, and human kallikrein 2 plus clinical information (age, DRE findings, and a history of prior negative biopsy result) into a proprietary algorithm to calculate an individual man’s percentage risk (< 1% to > 95%) of having Gleason score ≥ 7 if a prostate biopsy were to be performed. The 4Kscore Test has been extensively validated through a total of 12 prospective and retrospective studies published in peer-reviewed journals involving over 22,000 patients from both the United States and Europe.^16–23 These studies of men with elevated PSA levels involved cohorts of unscreened and screened men, and those with negative prior prostate biopsy results. Based on analyses published in these studies, the 4Kscore Test would have theoretically resulted in a 45% reduction in prostate biopsies while delaying the diagnosis of aggressive prostate cancer in only a few men (1.3%–4.7%).The 4Kscore Test is used to accurately determine percentage risk for aggressive prostate cancer (Gleason score ≥ 7) and provide additional information for men being considered for prostate biopsy because of abnormal PSA levels and/or DRE results. This allows urologists to better risk stratify men for biopsy and ultimately results in more selective treatment of those men with aggressive disease. Conversely, those men not harboring life-threatening disease are able to safely avoid prostate biopsy and overtreatment of indolent disease.With the introduction of any new diagnostic test such as the 4Kscore Test into clinical practice, it is important to assess whether its implementation, in this case as a follow-up test for an abnormal PSA and/or DRE result, influences and changes the physician-patient shared decision-making process and leads to an actual reduction in prostate biopsies. Herein we evaluated the influence of the 4Kscore Test on urologist-patient decisions about proceeding with biopsy in men who have an abnormal PSA and/or DRE result from multiple academic and community urology clinical practices in the United States.