Plasma GRP-like immunoreactivity in healthy and diseased subjects

Gastrin releasing peptide(GRP)-like immunoreactivity in human plasma was measured using radioimmunoassay of neuromedin C (NMC) in 83 healthy and 58 diseased subjects. In the healthy group, the mean value of fasting GRP-like immunoreactivity was 2.1±1.4 (mean±SD) pmol/L. There was a slight positive correlation between the GRP-like immunoreactivity values and aging. Postprandial serial measurements demonstrated that GRP-like immunoreacitivity showed no response to a significant elevation of serum gastrin concentration. The group with chronic renal failure on hemodialysis gave the highest value, 7.1+2.1 pmol/L (p<0.01). There were no statistical differences between the healthy controls and groups with peptic ulcer, liver cirrhosis, diabetes mellitus or carcinomas, although some cancer patients had a marked increase in GRP-like immunoreactivity value.     

Very Long-Term Prognostic Role of Admission BNP in Non-ST Segment Elevation Acute Coronary Syndrome

Background

BNP has been extensively evaluated to determine short- and intermediate-term prognosis in patients with acute coronary syndrome, but its role in long-term mortality is not known.

Objective

To determine the very long-term prognostic role of B-type natriuretic peptide (BNP) for all-cause mortality in patients with non-ST segment elevation acute coronary syndrome (NSTEACS).

Methods

A cohort of 224 consecutive patients with NSTEACS, prospectively seen in the Emergency Department, had BNP measured on arrival to establish prognosis, and underwent a median 9.34-year follow-up for all-cause mortality.

Results

Unstable angina was diagnosed in 52.2%, and non-ST segment elevation myocardial infarction, in 47.8%. Median admission BNP was 81.9 pg/mL (IQ range = 22.2; 225) and mortality rate was correlated with increasing BNP quartiles: 14.3; 16.1; 48.2; and 73.2% (p < 0.0001). ROC curve disclosed 100 pg/mL as the best BNP cut-off value for mortality prediction (area under the curve = 0.789, 95% CI= 0.723-0.854), being a strong predictor of late mortality: BNP < 100 = 17.3% vs. BNP ≥ 100 = 65.0%, RR = 3.76 (95% CI = 2.49-5.63, p < 0.001). On logistic regression analysis, age >72 years (OR = 3.79, 95% CI = 1.62-8.86, p = 0.002), BNP ≥ 100 pg/mL (OR = 6.24, 95% CI = 2.95-13.23, p < 0.001) and estimated glomerular filtration rate (OR = 0.98, 95% CI = 0.97-0.99, p = 0.049) were independent late-mortality predictors.

Conclusions

BNP measured at hospital admission in patients with NSTEACS is a strong, independent predictor of very long-term all-cause mortality. This study allows raising the hypothesis that BNP should be measured in all patients with NSTEACS at the index event for long-term risk stratification.     

吴茱萸次碱治疗重症急性胰腺炎的实验研究

目的：探讨吴茱萸次碱对大鼠重症急性胰腺炎（SAP）的疗效及其机制。 方法：50只SD大鼠随机均分为假手术组和4个实验组,实验组大鼠以5%牛磺胆酸钠胰胆管逆行注射制作SAP模型后,分别给予生理盐水、乌司他丁、吴茱萸次碱、乌司他丁+吴茱萸次碱处理。术后24 h,行病理学检查,并检测各组血清淀粉酶活性及血浆与胰腺组织和内皮素1（EF-1）、降钙素基因相关肽（CGRP）水平。 结果：除假手术组外,各实验组大鼠均胰腺组织均出现不同程度的胰腺炎病理改变;与假手术组比较,各实验组均出现不同程度的血清淀粉酶活性升高,血浆与胰腺组织ET-1浓度增加,而血浆与胰腺组织CGRP含量在吴茱萸次碱处理组与联合用药组均明显升高（均P<0.05）,其余实验组无明显改变（均P>0.05）;实验组中,各药物处理组胰腺病变程度、血清淀粉酶活性、血浆与胰腺组织ET-1浓度均较生理盐水处理的模型组明显降低,且均以联合用药组最为明显（均P<0.05）。 结论：吴茱萸次碱对大鼠SAP具有治疗作用,其作用可能与增加CGRP水平从而改善胰腺组织微循环有关。     

Identification of a peptide targeting CD56

Neural cell adhesion molecule 1 (NCAM1/CD56) is expressed on immune cells, myoblasts, and malignant cells, and there is a growing demand for the genetic detection of CD56 and CD56-targeted therapy. In the present study, we developed a novel peptide ligand (designated Natein) that binds to human CD56 by using T7 phage display technology. Natein recognized the extracellular region of CD56 and could bind to natural killer (NK) cells and CD56-positive (CD56⁺) cancer cells. CD56⁺ cells enriched from human peripheral blood mononuclear cells (PBMCs) using biotinylated Natein-conjugated microbeads, similarly to CD56 antibody-isolated cells, demonstrated functional cytotoxicity against K562 cells. In addition, Natein could be used to stain CD56⁺ lymphoma cells in nasal-type extranodal NK/T-cell lymphoma tissues similarly to a CD56 antibody. These findings suggest that Natein has the potential to be alternative to CD56 antibody that could be used for peptide-based cell isolation and diagnosis.     

A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers

Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may represent a promising biomaterial for use in bioengineered peripheral nerve repair.     

Peptide encapsulation regulated by the geometry of carbon nanotubes

In this work the encapsulation of an α-helical peptide in single carbon nanotubes (CNTs) with similar diameter and length but different geometry (armchair and zigzag) was investigated through molecular dynamics simulations and free energy calculations. Our simulation results showed that in vacuo it makes no evident difference whether the investigated peptide is encapsulated in armchair or zigzag CNTs; however, in aqueous solution the armchair CNT encapsulates the peptide remarkably easier than the zigzag CNT does. A detailed analysis revealed that the equilibrium conformation of the water molecules inside the CNTs with varying geometry mediates the peptide encapsulation. It suggests that the water molecules play an important role in regulating behaviors of biomolecules in bio-systems. Then the impact of the CNT geometry on the conformational changes of the confined peptide was studied. Analyses of secondary structures showed the α-helix of the peptide could be better maintained in the zigzag CNT.     

Uncoupling angiogenesis and inflammation in peripheral artery disease with therapeutic peptide-loaded microgels

Peripheral artery disease (PAD) is characterized by vessel occlusion and ischemia in the limbs. Treatment for PAD with surgical interventions has been showing limited success. Moreover, recent clinical trials with treatment of angiogenic growth factors proved ineffective as increased angiogenesis triggered severe inflammation in a proportionally coupled fashion. Hence, the overarching goal of this research was to address this issue by developing a biomaterial system that enables controlled, dual delivery of pro-angiogenic C16 and anti-inflammatory Ac-SDKP peptides in a minimally-invasive way. To achieve the goal, a peptide-loaded injectable microgel system was developed and tested in a mouse model of PAD. When delivered through multiple, low volume injections, the combination of C16 and Ac-SDKP peptides promoted angiogenesis, muscle regeneration, and perfusion recovery, while minimizing detrimental inflammation. Additionally, this peptide combination regulated inflammatory TNF-α pathways independently of MMP-9 mediated pathways of angiogenesis in vitro, suggesting a potential mechanism by which angiogenic and inflammatory responses can be uncoupled in the context of PAD. This study demonstrates a translatable potential of the dual peptide-loaded injectable microgel system for PAD treatment.     

Vitamin D receptor gene polymorphism as possible risk factor in rheumatoid arthritis and rheumatoid related osteoporosis

Objective

To study the role of VDR polymorphisms as risk factor for RA and osteoporosis, and whether osteoporosis complicating RA is due to RA or VDR polymorphisms.

Methods

VDR gene polymorphisms ApaI, TaqI, BsmI and FokI were typed by RFLP for 128 RA patients, 30 postmenopausal osteoporotic females and 150 healthy controls.

Results

Significant differences were found between patients and healthy controls in the frequency of BsmI and TaqI (Pc < 0.05) but no significant associations were found for FokI and ApaI polymorphisms except for aa genotype (Pc < 0.001). Titers of RF were higher with aa and bb genotypes. Anti-CCP and CRP levels were higher with aa genotype and more bone loss was associated with Bb genotype. Ff genotype frequency was higher in RA patients with osteoporosis than those without osteoporosis.

Conclusions

The ApaI, BsmI and TaqI polymorphisms may be a susceptibility risk factors for RA and the Ff genotype may be responsible for development of osteoporosis in RA Egyptian patients. However, the present study needs to be replicated in a large number of patients from allover the Egypt and also in multi-ethnic populations.     

Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers

Poly-l-lysine (PLL), in α-helix or β-sheet configuration, was used as a model peptide for investigating the effect of secondary structures on adsorption events to poly(ethylene oxide) (PEO) modified surfaces formed using θ solvents. Circular dichroism results showed that the secondary structure of PLL persisted upon adsorption to Au and PEO modified Au surfaces. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the chemisorbed PEO layer in different solvents (θ and good solvents), as well as the sequential adsorption of PLL in different secondary structures (α-helix or β-sheet). QCM-D results suggest that chemisorption of PEO 750 and 2000 from θ solutions led to brushes 3.8 ± 0.1 and 4.5 ± 0.1 nm thick with layer viscosities of 9.2 ± 0.8 and 4.8 ± 0.5 cP, respectively. The average number of H₂O per ethylene oxides, while in θ solvent, was determined as ∼0.9 and ∼1.2 for the PEO 750 and 2000 layers, respectively. Upon immersion in good solvent (as used for PLL adsorption experiments), the number of H₂O per ethylene oxides increased to ∼1.5 and ∼2.0 for PEO 750 and 2000 films, respectively. PLL adsorbed masses for α-helix and β-sheet on Au sensors was 231 ± 5 and 1087 ± 14 ng cm⁻², with layer viscosities of 2.3 ± 0.1 and 1.2 ± 0.1 cP, respectively; suggesting that the α-helix layer was more rigid, despite a smaller adsorbed mass, than that of β-sheet layers. The PEO 750 layer reduced PLL adsorbed amounts to ∼10 and 12% of that on Au for α-helices and β-sheets respectively. The PLL adsorbed mass to PEO 2000 layers dropped to ∼12% and 4% of that on Au, for α-helix and β-sheet respectively. No significant differences existed for the viscosities of adsorbed α-helix and β-sheet PLL on PEO surfaces. These results provide new insights into the fundamental understanding of the effects of secondary structures of peptides and proteins on their surface adsorption.     

The relative importance of individual DR binding motif positions as defined by peptide anchor analysis of influenza hemagglutinin peptide 306–318 and human myelin basic protein peptide 152–165 binding to several DR molecules: definition of a common extended DR binding motif

Definition of peptide binding motifs for DR molecules has proven difficult as the peptides that bind to a DR molecule have shown extensive variability at putative motif positions. Recent studies suggest that specific peptide anchor residues (motif positions) and specific DR residues can differ in importance for peptide binding to a DR molecule. To assess further the relevance of individual peptide anchor residues, the binding of serial alanine-substituted analogs of influenza virus hemagglutinin (HA) 306–318 and human myelin basic protein (MBP) 152–165 to a panel of transfected wild-type DR molecules was examined. This analysis included DR molecules from a wide range of allelic families and, unlike most earlier studies, multiple members of single DR allelic families. The data show that different peptide residues serve as critical anchors for binding to different DR molecules. For example, MBP binding to DR(α,β1*0303) required peptide residues F154 (i), R159 (i + 5) and R162 (i + 8). In contrast, MBP binding to DR(α,β1*0102) required peptide residues I153 (i) and L156 (i + 3). More importantly, the combination of critical anchor residues in HA and MBP differed for binding to a single DR molecule [e.g. V309 (i) for HA and I153 (i) and L156 (i + 3) for MBP binding to DR(α,β1*0102)]. Although the location of the binding pocket in each DR molecule compared to the DR (α,β1*0101) crystal is expected to be similar and suggests a common extended DR binding motif, the present results suggest that the relative importance of individual peptide anchor residues and of the corresponding DR binding pockets will differ for each DR/peptide complex.