Novel T-cell inhibiting peptides delay the onset of Type 1 diabetes in non-obese diabetic mice

The aim of this study was to investigate the effectiveness of immunomodulatory peptides in preventing the spontaneous onset of Type 1 diabetes in NOD mice. Two such peptides, CP and C1, were injected intraperitoneally in NOD mice three times a week starting at two different time points, nine weeks and 11 weeks of age, and blood sugar levels monitored for the development of diabetes. CP was shown to be effective in delaying the onset of diabetes compared to control (P = 0.006). The timing of peptide administration was crucial since delay in treatment did not prevent the onset of diabetes (nine weeks versus 11 weeks of age). C1 was effective in delaying the onset of Type 1 diabetes with borderline significance when given at week 11 (P = 0.05). These findings confirm the efficacy of these peptides in the prevention and possible treatment for Type 1 diabetes and thereby create new opportunities for genetic manipulation.     

VIP and -ala-peptide T-amide release chemokines which prevent HIV-1 GP120-induced neuronal death

Vasoactive intestinal peptide (VIP) and DAPTA ( -ala₁-peptide T-amide, a gp120-derived octapeptide homologous to VIP) prevent neuronal cell death produced by five variants of HIV-1 (human immunodeficiency virus) envelope protein (gp120). VIP or DAPTA treatment of astrocyte cultures resulted in the release of macrophage inflammatory protein-1α (MIP-1α) and RANTES, beta chemokines known to block gp120 interactions with microglial chemokine receptors. In rat cerebral cortical cultures, gp120-induced neuronal killing was partially or completely prevented by chemokines that stimulate the CXCR4, CCR3 or CCR5 chemokine receptors. Chemokines exhibited marked differences in potency and efficacy in preventing toxicity associated with five gp120 variants (LAV/BRU, CM243, RF, SF2, and MN). RANTES had the broadest and most potent inhibition (IC₅₀<3 pM for RF isolate). An octapeptide derived from RANTES also exhibited neuroprotection from gp120 (RF isolate) toxicity (IC₅₀=0.3 μM). Treatment with chemokines alone had no detectable effect on neuronal cell number. However, antiserum to MIP-1α produced neuronal cell death that was prevented by co-treatment with MIP-1α, suggesting that this endogenous chemokine exerts a tonic regulation important to neuronal survival. The neuroprotective action of VIP on gp120 was attenuated by co-treatment with anti-MIP-1α. These studies suggest that the neuroprotective action of VIP is linked in part to its release of MIP-1α. Furthermore, neuroprotection produced by chemokines is dependent on both the type of chemokine and the variant structure of gp120 and may be relevant to drug strategies for the treatment of AIDS dementia.     

Sequence-specific DNA strand cleavage by <Superscript>111</Superscript>In-labeled peptide nucleic acids

Peptide nucleic acids (PNAs) bind tightly and sequence-specifically to single- and double-stranded nucleic acids, and are hence of interest in the design of gene-targeted radiotherapeutics that could deliver the radiodamage to designated DNA and/or RNA sites. As a first step towards this goal, we developed a procedure for incorporation of Auger electron-emitting radionuclide (indium-111) into PNA oligomers and studied the efficiency of PNA-directed cleavage of single-stranded DNA targets. Accordingly, diethylene triamine penta-acetic acid (DTPA) was conjugated to the lysine-appended mixed-base PNAs and sequence-homologous DNA oligomer with a proper linker for comparative studies. By chelation of PNA-DTPA and DNA-DTPA conjugates with ¹¹¹In³⁺ in acidic aqueous solutions, ¹¹¹In-labeled PNA and DNA oligomers were obtained. Targeting of single-stranded DNA with PNA-DTPA-[¹¹¹In] conjugates yielded highly localized DNA strand cleavage; the distribution of breaks along the target DNA strand has two maxima corresponding to both termini of PNA oligomer. After 10–14 days, the overall yield of breaks thus generated within the PNA-targeted DNA by ¹¹¹In decay was 5–7% versus 2% in the case of control oligonucleotide DNA-DTPA-[¹¹¹In]. The estimated yield of DNA strand breaks per nuclear decay is ~0.1 for the PNA-directed delivery of ¹¹¹In, which is three times more than for the DNA-directed delivery of this radionuclide. This in vitro study shows that ¹¹¹In-labeled PNAs are much more effective than radiolabeled DNA oligonucleotides for site-specific damaging of DNA targets. Accordingly, we believe that PNA oligomers are promising radionuclide delivery tools for future antisense/antigene radiotherapy trials.     

Outpatient treatment of symptomatic pulmonary embolism: A systematic review and meta-analysis

Background

Patients with acute deep vein thrombus (DVT) can safely be treated as outpatients. However the role of outpatient treatment in patients diagnosed with a pulmonary embolism (PE) is controversial. We sought to determine the safety of outpatient management of patients with acute symptomatic PE.

Materials and Methods

A systematic literature search strategy was conducted using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and all EBM Reviews. Pooled proportions for the different outcomes were calculated.

Results

A total of 1258 patients were included in the systematic review. The rate of recurrent venous thromboembolism (VTE) in patients with PE managed as outpatients was 1.47% (95% CI: 0.47 to 3.0%; I²: 65.4%) during the 3 month follow-up period. The rate of fatal PE was 0.47% (95% CI: 0.16 to 1.0%; I²: 0%). The rates of major bleeding and fatal intracranial hemorrhage were 0.81% (95% CI: 0.37 to 1.42%; I²: 0%) and 0.29% (95% CI: 0.06 to 0.68%; I²: 0%), respectively. The overall 3 month mortality rate was 1.58% (95% CI: 0.71 to 2.80%; I²: 45%). The event rates were similar if employing risk stratification models versus using clinical gestalt to select appropriate patients for outpatient management.

Conclusions

Independent of the risk stratification methods used, the rate of adverse events associated with outpatient PE treatment seems low. Based on our systematic review and pooled meta-analysis, low-risk patients with acute PE can safely be treated as outpatients if home circumstances are adequate.     

Enteroendocrine secretion after roux‐en‐Y gastric bypass: is it important?

Observational studies suggest that bariatric surgery is the most effective intervention for achieving a significant and durable weight loss. In patients with type 2 diabetes, such surgery is often associated with remission of their diabetes. The mechanism(s) by which surgeries such as Roux‐en‐Y Gastric Bypass (RYGB) leads to favorable effects on glucose metabolism remain unknown. RYGB is associated with altered secretion of enteroendocrine hormones, leading to the belief that these hormones contribute to the improvement in insulin secretion and action as well as satiation after this procedure. However, it is important to consider the not insignificant effects of caloric restriction and the mechanical changes to the upper gut in determining the outcomes of such surgery.     

Inhibition of calpain-mediated cell death by a novel peptide inhibitor

Calpains are calcium- and thiol-dependent proteases whose overactivation and degradation of various substrates have been implicated in a number of diseases and conditions such as cardiovascular dysfunction and ischemic stroke. With increasing evidence for calpain's role in cellular damage, the development of calpain inhibitors continues to be an important objective. Previously, we identified a highly specific calcium-dependent, calpain interacting peptide L-S-E-A-L, that showed homology to domains A and C of the only known endogenous inhibitor of calpains, calpastatin. This suggested that LSEAL had a calpain inhibitory function and synthetic LSEAL inhibited calpain I and II proteolysis of two calpain substrates, tau and alpha-synuclein. In the present study, we demonstrate that synthetic LSEAL is membrane permeable and is a potent inhibitor in two established models of calpain-mediated cell death using primary rat cortical neurons and SH-SY5Y neuroblastoma cells. In addition, we show that LSEAL inhibits calpain activity towards protein substrates as detected by an antibody to a calpain-specific breakdown product of spectrin. Taken together, these results suggest that LSEAL may represent a novel calpastatin mimetic with the potential for benefit in conditions of increased calpain activity such as stroke, traumatic brain injury or heart attack.     

<Superscript>99m</Superscript>Tc-chelator engineering to improve tumour targeting properties of a HER2-specific Affibody molecule

Purpose Monitoring HER2 expression is crucial for selection of breast cancer patients amenable to HER2-targeting therapy. The Affibody molecule Z_HER2:342 binds to HER2 with picomolar affinity and enables specific imaging of HER2 expression. Previously, Z_HER2:342 with the additional N-terminal mercaptoacetyl-glycyl-glycyl-glycyl (maGGG) sequence was labelled with ^99mTc and demonstrated specific targeting of HER2-expressing xenografts. However, hepatobiliary excretion caused high radioactivity accumulation in the abdomen. We investigated whether the biodistribution of Z_HER2:342 can be improved by substituting glycyl residues in the chelating sequence with more hydrophilic seryl residues. Methods The Affibody molecule Z_HER2:342, carrying the chelators mercaptoacetyl-glycyl-seryl-glycyl (maGSG), mercaptoacetyl-glycyl-D-seryl-glycyl [maG(D-S)G] and mercaptoacetyl-seryl-seryl-seryl (maSSS), were prepared by peptide synthesis and labelled with ^99mTc. The differences in the excretion pathways were evaluated in normal mice. The tumour targeting capacity of ^99mTc-maSSS-Z_HER2:342 was studied in nude mice bearing SKOV-3 xenografts and compared with the capacity of radioiodinated Z_HER2:342. Results A shift towards renal excretion was obtained when glycine was substituted with serine in the chelating sequence. The radioactivity in the gastrointestinal tract was reduced threefold for the maSSS conjugate in comparison with the maGGG conjugate 4 h post injection (p.i.). The tumour uptake of ^99mTc-maSSS-Z_HER2:342 was 11.5 ± 0.5% IA/g 4 h p.i., and the tumour-to-blood ratio was 76. The pharmacokinetics and uptake characteristics of technetium-labelled Z_HER2:342 were better than those of radioiodinated Z_HER2:342. Conclusion The introduction of serine residues in the chelator results in better tumour imaging properties of the Affibody molecule Z_HER2:342 compared with glycyl-containing chelators and is favourable for imaging of tumours and metastases in the abdominal area.     

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.     

降钙素基因相关肽对c-kit+心脏干细胞生存活力的影响

目的探讨降钙素基因相关肽(CGRP)对缺氧状态下c-kit~+心脏干细胞(c-kit~+CSC)生存活力的影响及其可能的机制。方法体外建立细胞缺氧模型,实验随机分为缺氧细胞组、CGRP+缺氧细胞组、CGRP+CGRP8-37+缺氧细胞组和对照组(不缺氧细胞);通过CCK-8法检测细胞的活力,采用流式细胞仪和线粒体膜电位法来检测细胞凋亡。结果在缺氧状态下,缺氧细胞组细胞增殖活力较对照组下降,CGRP作用缺氧细胞后不同时间点,与缺氧细胞组比较,细胞增殖活力均增加(P0.05),尤其以30 min和60 min最为明显;与CGRP+缺氧细胞组比较,CGRP+CGRP8-37+缺氧细胞组在30 min和60 min细胞增殖活力明显下降(P0.05)。流式细胞仪结果显示:与对照组比较,缺氧细胞组早期凋亡率最高(P0.05);与缺氧细胞组比较,CGRP+缺氧细胞组早期凋亡率降低(P0.05);与CGRP+缺氧细胞组比较,CGRP+CGRP8-37+缺氧细胞组早期凋亡率增高(P0.05)。线粒体膜电位结果显示:与缺氧细胞组比较,CGRP+缺氧细胞组红色荧光/绿色荧光比值增高(P0.05);与CGRP+缺氧细胞组比较,CGRP+CGRP8-37+缺氧细胞组红色荧光/绿色荧光比值降低(P0.05)。结论 CGRP能够促进缺氧状态下c-kit~+CSC增殖存活,抑制细胞早期凋亡。     

C—P、HbAlc、FBG联合检测对糖尿病肾病早期诊断和监测的临床应用价值

目的研究血清C肽、糖化血红蛋白、空腹血糖对糖尿痛肾病早期诊断和检测的临床应用价值。方法用磁微免分析方法测定血清C肽、生化分析仪检测糖化血红蛋白和空腹血糖。结果21例糖尿病肾病空腹平均C—P,餐后2h平均C—P分别为1．35±0．28ng／ml和4．08±1．12ng／m],平均糖化血红蛋白、空腹血糖为11．06±1．75％、9．20±3．02mmol／L,39例单纯糖尿病空腹平均C—P,餐后2h平均C—P分别为1．52±0．40ng／ml和4．19±1．02ng／m1,平均糖化血红蛋白、空腹血糖为9．26±2．38％、8．92±2．82mmol／L,两组比较无统计学意义（P〉0．05）．但与正常对照比较有统计学差异（P〈0．05）。结论联合测定血清C肽、糖化血红蛋白、空腹血糖有助于早期了解糖尿病患者的肾功能状况。