Enhanced Erythrocyte Adhesiveness/Aggregation in Obesity Corresponds to Low‐Grade Inflammation

Objective: Previous studies have suggested that obesity enhances the inflammatory response, producing macromolecules involved in the induction and/or maintenance of increased erythrocyte aggregation. The objectives of this study were to evaluate the correlation between inflammation markers, erythrocyte adhesiveness/aggregation, and the degree of obesity and to assess phosphatidylserine expression on erythrocyte surface membrane of obese vs. nonobese individuals. Research Methods and Procedures: Erythrocyte adhesiveness/aggregation in the peripheral venous blood was evaluated by using a new biomarker, phosphatidylserine expression was assessed by means of flow cytometry, and markers of inflammation were measured in 65 subjects: 30 obese [body mass index (BMI) = 41 ± 7.7 kg/m²] and 35 nonobese (BMI = 24 ± 2.7 kg/m²) individuals. Pearson correlations and Student's t test were performed. Results: A highly significant difference was noted in the degree of erythrocyte adhesiveness/aggregation and markers of inflammation between the study groups. BMI correlated with erythrocyte adhesiveness/aggregation (r = 0.42, p = 0.001), erythrocyte sedimentation rate (r = 0.42, p = 0.001), high‐sensitive C‐reactive protein (r = 0.55, p < 10^?4), fibrinogen (r = 0.37, p = 0.004), and white blood cell count (r = 0.45, p < 10^?4). The degree of erythrocyte adhesiveness/aggregation correlated with erythrocyte sedimentation rate (r = 0.5, p < 10^?4), high‐sensitive C‐reactive protein (r = 0.56, p < 10^?4), fibrinogen (r = 0.54, p < 10^?4), and white blood cell count (r = 0.32, p = 0.01). Discussion: Our results suggest that obesity‐related erythrocyte adhesiveness/aggregation is probably mediated through increased concentrations of adhesive macromolecules in the circulation and not necessarily through hyperlipidemia or phosphatidylserine exposure on erythrocyte's membrane.     

CRP velocity and short-term mortality in ST segment elevation myocardial infarction

Context: There is a known association between C-reactive protein (CRP) levels and adverse outcomes in patients presenting with ST-elevation myocardial infarction (STEMI). The optimal time frame to measure CRP for risk stratification is not known.

Objective: The aim of the current study was to evaluate the relation between the change in CRP velocity (CRPv) and 30-d mortality among STEMI patients.

Material and methods: We included consecutive patients with a diagnosis of STEMI who presented to Tel-Aviv Medical Center between 2008 and 2014 and had their CRP measured with a wide range assay (wr-CRP) at least twice during the 24?h after admission. CRPv was defined as the change in wr-CRP concentration (mg/l) divided by the change in time (in hours) between the two measurements.

Results: The study population comprised of 492 patients, mean age was 62?±?14, 80% were male. CRPv was significantly higher among patients who died within 30 d of admission (1.42?mg/l versus 0.18?mg/l, p?<?0.001). In a multivariate regression model adjusted to multiple confounders, CRPv was independently associated with 30-d mortality (OR 1.39, 95% CI: 1.20–1.62, p?<?0.001).

Conclusion: CRPv might be an independent and rapidly measurable biomarker for short-term mortality in patients presenting with STEMI.     

Membrane-proximal external HIV-1 gp41 motif adapted for destabilizing the highly rigid viral envelope

Electron microscopy structural determinations suggest that the membrane-proximal external region (MPER) of glycoprotein 41 (gp41) may associate with the HIV-1 membrane interface. It is further proposed that MPER-induced disruption and/or deformation of the lipid bilayer ensue during viral fusion. However, it is predicted that the cholesterol content of this membrane (∼45 mol %) will act against MPER binding and restructuring activity, in agreement with alternative structural models proposing that the MPER constitutes a gp41 ectodomain component that does not insert into the viral membrane. Here, using MPER-based peptides, we test the hypothesis that cholesterol impedes the membrane association and destabilizing activities of this gp41 domain. To that end, partitioning and leakage assays carried out in lipid vesicles were combined with x-ray reflectivity and grazing-incidence diffraction studies of monolayers. CpreTM, a peptide combining the carboxyterminal MPER sequence with aminoterminal residues of the transmembrane domain, bound and destabilized effectively cholesterol-enriched membranes. Accordingly, virion incubation with this peptide inhibited cell infection potently but nonspecifically. Thus, CpreTM seems to mimic the envelope-perturbing function of the MPER domain and displays antiviral activity. As such, we infer that CpreTM bound to cholesterol-enriched membranes would represent a relevant target for anti-HIV-1 immunogen and inhibitor development.     

Neuroprotective effects of Mycoplasma hyorhinis against amyloid-β-peptide toxicity in SH-SY5Y human neuroblastoma cells are mediated by calpastatin upregulation in the mycoplasma-infected cells

Mycoplasmas are frequent contaminants of cell cultures. Contamination leads to altered synthetic and metabolic pathways. We have found that contamination of neuroblastoma SH-SY5Y cells by a strain of Mycoplasma hyorhinis derived from SH-SY5Y cell culture (NDMh) leads to increased levels of calpastatin (the endogenous inhibitor of the Ca(2+)-dependent protease, calpain) in NDMh-infected cells. We have now examined effects of amyloid-β-peptide (Aβ) (central to the pathogenesis of Alzheimer's disease) on uncontaminated (clean) and NDMh-infected SH-SY5Y cells. Aβ was toxic to clean cells, resulting in necrotic cell damage. Aβ treatment led to activation of calpain and enhanced proteolysis, cell swelling, cell membrane permeability to propidium iodide (PI) (without nuclear apoptotic changes), and diminished mitochondrial enzyme activity (XTT reduction). Aβ-toxicity was attenuated in the high calpastatin-containing NDMh-infected cells, as shown by inhibition of calpain activation and activity, no membrane permeability, normal cell morphology, and maintenance of mitochondrial enzyme activity (similar to attenuation of Aβ-toxicity in non-infected cells overexpressing calpastatin following calpastatin-plasmid introduction into the cells). By contrast, staurosporine affected both clean and infected cells, causing apoptotic damage (cell shrinkage, nuclear apoptotic alterations, caspase-3 activation and caspase-promoted proteolysis, without PI permeability, and without effect on XTT reduction). The results indicate that mycoplasma protects the cells against certain types of insults involving calpain. The ratio of calpastatin to calpain is an important factor in the control of calpain activity. Exogenous pharmacological means, including calpastatin-based inhibitors, have been considered for therapy of various diseases in which calpain is implicated. Mycoplasmas provide the first naturally occurring biological system that upregulates the endogenous calpain inhibitor, and thus may be of interest in devising treatments for some disorders, such as neurodegenerative diseases.     

The monomeric, tetrameric, and fibrillar organization of Fib: the dynamic building block of the bacterial linear motor of Spiroplasma melliferum BC3

Spiroplasmas belong to the class Mollicutes, representing the minimal, free-living, and self-replicating forms of life. Spiroplasmas are helical wall-less bacteria and the only ones known to swim by means of a linear motor (rather than the near-universal rotary bacterial motor). The linear motor follows the shortest path along the cell's helical membranal tube. The motor is composed of a flat monolayered ribbon of seven parallel fibrils and is believed to function in controlling cell helicity and motility through dynamic, coordinated, differential length changes in the fibrils. The latter cause local perturbations of helical symmetry, which are essential for net directional displacement in environments with a low Reynolds number. The underlying fibrils' core building block is a circular tetramer of the 59-kDa protein Fib. The fibrils' differential length changes are believed to be driven by molecular switching of Fib, leading consequently to axial ratio and length changes in tetrameric rings. Using cryo electron microscopy, diffractometry, single-particle analysis of isolated ribbons, and sequence analyses of Fib, we determined the overall molecular organization of the Fib monomer, tetramer, fibril, and linear motor of Spiroplasma melliferum BC3 that underlies cell geometry and motility. Fib appears to be a bidomained molecule, of which the N-terminal half is apparently a globular phosphorylase. By a combination of reversible rotation and diagonal shift of Fib monomers, the tetramer adopts either a cross-like nonhanded conformation or a ring-like handed conformation. The sense of Fib rotation may determine the handedness of the linear motor and, eventually, of the cell. A further change in the axial ratio of the ring-like tetramers controls fibril lengths and the consequent helical geometry. Analysis of tetramer quadrants from adjacent fibrils clearly demonstrates local differential fibril lengths.     

Comparable Long-Term Efficacy of Lopinavir/Ritonavir and Similar Drug-Resistance Profiles in Different HIV-1 Subtypes

Background

Analysis of potentially different impact of Lopinavir/Ritonavir (LPV/r) on non-B subtypes is confounded by dissimilarities in the conditions existing in different countries. We retrospectively compared its impact on populations infected with subtypes B and C in Israel, where patients infected with different subtypes receive the same treatment.

Methods

Clinical and demographic data were reported by physicians. Resistance was tested after treatment failure. Statistical analyses were conducted using SPSS.

Results

607 LPV/r treated patients (365 male) were included. 139 had HIV subtype B, 391 C, and 77 other subtypes. At study end 429 (71%) were receiving LPV/r. No significant differences in PI treatment history and in median viral-load (VL) at treatment initiation and termination existed between subtypes. MSM discontinued LPV/r more often than others even when the virologic outcome was good (p = 0.001). VL was below detection level in 81% of patients for whom LPV/r was first PI and in 67% when it was second (P = 0.001). Median VL decrease from baseline was 1.9±0.1 logs and was not significantly associated with subtype. Median CD4 increase was: 162 and 92cells/µl, respectively, for patients receiving LPV/r as first and second PI (P = 0.001), and 175 and 98, respectively, for subtypes B and C (P<0.001). Only 52 (22%) of 237 patients genotyped while under LPV/r were fully resistant to the drug; 12(5%) were partially resistant. In48%, population sequencing did not reveal resistance to any drug notwithstanding the virologic failure. No difference was found in the rates of resistance development between B and C (p = 0.16).

Conclusions

Treatment with LPV/r appeared efficient and tolerable in both subtypes, B and C, but CD4 recovery was significantly better in virologically suppressed subtype-B patients. In both subtypes, LPV/r was more beneficial when given as first PI. Mostly, reasons other than resistance development caused discontinuation of treatment.     

Screening additional wild tomatoes for resistance to the whitefly-borne tomato yellow leaf curl virus

Plants of 25 wild Lycopersicon accessions were screened in the greenhouse for resistance to the whitefly-borne tomato yellow leaf curl virus (TYLCV). High levels of resistance were detected in 7 of 9 accessions of L. peruvianum and in all 5 accessions of L. chilense tested. In contrast, plants of 7 accessions of L. hirsutum and 3 of 4 accessions of L. pimpinellifolium were highly susceptible. Plants of accession CIAS 27 (L. pimpinellifolium) showed moderate resistance to TYLCV.