Effect of aging and caloric restriction on the mitochondrial proteome

The rat mitochondrial proteome was analyzed using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), and proteins altered by age or caloric restriction (CR) were identified using mass spectrometry. Of 2061 mitochondrial proteins analyzed in the three tissues, a significant change with age occurred in 25 liver proteins (19 increased, 6 decreased), 3 heart proteins (1 increased, 2 decreased), and 5 skeletal muscle proteins (all increased). CR prevented the age-related change in the level of one liver mitochondrial protein, altered the levels of four proteins (one increased, three decreased) from heart, and one protein (decreased) from skeletal muscle. Identification of the proteins that changed with age or CR revealed that they were varied among the three tissues, that is, not one mitochondrial protein was changed, in common, by age or CR in any tissue studied. Thus, the effect of age on the mitochondrial proteome appears to be tissue-specific, and CR has a minor effect on age-related protein changes.     

Prostate-specific membrane antigen (PSMA)-mediated laminin proteolysis generates a pro-angiogenic peptide

Prostate-specific membrane antigen (PSMA) is a membrane-bound glutamate carboxypeptidase expressed in a number of tissues. PSMA participates in various biological functions depending on the substrate available in the particular tissue; in the brain, PSMA cleaves the abundant neuropeptide N-acetyl-aspartyl-glutamate to regulate release of key neurotransmitters, while intestinal PSMA cleaves polyglutamated peptides to supply dietary folate. PSMA expression is also progressively upregulated in prostate cancer where it correlates with tumor progression as well as in tumor vasculature, where it regulates angiogenesis. The previous research determined that PSMA cleavage of small peptides generated via matrix metalloprotease-mediated proteolysis of the extracellular matrix protein laminin potently activated endothelial cells, integrin signaling and angiogenesis, although the specific peptide substrates were not identified. Herein, using enzymatic analyses and LC/MS, we unequivocally demonstrate that several laminin-derived peptides containing carboxy-terminal glutamate moieties (LQE, IEE, LNE) are bona fide substrates for PSMA. Subsequently, the peptide products were tested for their effects on angiogenesis in various models. We report that LQ, the dipeptide product of PSMA cleavage of LQE, efficiently activates endothelial cells in vitro and enhances angiogenesis in vivo. Importantly, LQE is not cleaved by an inactive PSMA enzyme containing an active site mutation (E424S). Endothelial cell activation by LQ was dependent on integrin beta-1-induced activation of focal adhesion kinase. These results characterize a novel PSMA substrate, provide a functional rationale for the upregulation of PSMA in cancer cells and tumor vasculature and suggest that inhibition of PSMA could lead to the development of new angiogenic therapies.     

Pregnancy and the risk of HIV-1 acquisition among women in Uganda and Zimbabwe

OBJECTIVE: Several studies have suggested that pregnancy is associated with an increased risk of HIV-1 acquisition. We used data from a large, prospective study of hormonal contraception and HIV-1 to evaluate the effect of pregnancy on the risk of HIV-1 acquisition. DESIGN: A multicenter prospective cohort study. METHODS: We examined 4439 women from family planning sites in Uganda and Zimbabwe contributing 31 369 follow-up visits during 1999-2004. Participants were aged 18-35 years, and had received pregnancy and HIV-1 testing quarterly for 15-24 months. Using proportional hazards modeling, we compared the time to HIV-1 acquisition among four groups: pregnant women, non-pregnant lactating (NP/L) women, and women neither pregnant nor lactating (NP/NL) who were either using or not using hormonal contraception. RESULTS: A total of 211 participants became HIV-1 infected (2.7 per 100 woman-years; wy), including 13 pregnant women (1.6 per 100 wy), 33 NP/L women (2.7 per 100 wy), 126 NP/NL women using hormonal contraception (2.9 per 100 wy), and 39 NP/NL women not using hormonal contraception (2.7 per 100 wy). In multivariable analysis adjusting for site, age, living with partner, risky sexual behaviors, and incident vaginal, cervical and herpes simplex virus 2 infections, neither pregnant, NP/L, nor NP/NL women using hormonal contraception were at an increased risk of HIV-1 acquisition compared with NP/NL women not using hormonal contraception. CONCLUSION: Neither pregnancy nor lactation placed women at increased risk of HIV-1 acquisition in this multisite, prospective study of African women. This information is important in planning interventions to reduce HIV-1 acquisition among women.     

Cardiopulmonary resuscitation training for family members of patients on cardiac rehabilitation programmes in Scotland.

Existing cardiopulmonary resuscitation (CPR) training programmes have failed to reach those most likely to witness a cardiac arrest, such as families of cardiac patients. In 1993, the Scottish Health Service Advisory Committee suggested that CPR training could be offered as part of cardiac rehabilitation programmes. A survey was carried out to identify the current extent and nature of such training and factors influencing its provision. Questionnaires were mailed to all the 45 Scottish cardiac rehabilitation programmes on the British Heart Foundation's register. A 93% response rate was achieved. Only 37% of programmes provided information to families about attending a CPR course and 37% actually provided CPR training The numbers trained by these programmes were very small. Hospital programmes were significantly more likely than community programmes to provide CPR training (chi2 = 6.65, P < 0.01) as were those which included an exercise component (chi2 = 7.63, P < 0.01). Reasons for not providing training ranged from lack of resources and lack of staff training, to not having considered it. CPR training is provided as part of cardiac rehabilitation programmes to a limited extent. Ways of recruiting and increasing the number of family members of cardiac patients who are trained in CPR need to be found.     

Adherence to evidence-based guidelines for heart failure in physicians and their patients: lessons from the Heart Failure Adherence Retention Trial (HART)

The Heart Failure Adherence and Retention Trial (HART) provided an opportunity to determine adherence to evidence-based guidelines (EBG) in patients with heart failure (HF). Ten hospitals were the source of 692 patients with HF (EF < 40%). Physicians of patients with HF were classified as adherent to EBG if the patient chart audit showed they were on a beta-blocker, ACE-inhibitor (ACE-I), or angiotensin receptor blocker (ARB). Patients were classified as adherent to EBG if MEMS pill caps were used appropriately more than 80% of the time. Sixty-three percent of physicians prescribed evidence-based medications that were adherent to clinical practice guidelines. New York Heart Association (NYHA) III patients were less likely to be adherent (P < 0.001), as were those with renal disease (P < 0.001) and asthmatics (P < 0.001). Nonadherent physicians were less likely to treat patients with beta-blockers (39% vs 98%, P < 0.001) and ACE-I or ARBs (71% vs 98% P < 0.001). Thirty-seven percent of patients prescribed evidence-based therapy failed to use the MEMS pill cap bottles appropriately and were more likely a minority or higher NYHA class. Adherence to evidence-based therapy is less than optimal in HF patients based on a combination of both physician and patient nonadherence.     

Pulmonary function over 2 years in diabetic patients treated with prandial inhaled Technosphere Insulin or usual antidiabetes treatment: a randomized trial

Aims: Development of inhaled insulin has increased the need to understand its pulmonary safety. This study evaluated pulmonary function changes in diabetes patients receiving inhaled Technosphere Insulin (TI) or usual antidiabetes treatment (usual care). Methods: This randomized, open‐label study was conducted at 220 sites (25 July 2005 to 29 August 2008). Pulmonary function tests [forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), total lung capacity (TLC) and lung diffusion capacity for carbon monoxide (DL_CO)] were prospectively followed over 2 years in patients with type 1 or type 2 diabetes receiving TI (n = 730) or usual care (n = 824), along with a cohort without diabetes not receiving any specific therapy (n = 145). Results: Baseline demographics and pulmonary function were similar between diabetes treatment groups. Lung function declined from baseline in all groups. TI was non‐inferior to usual care for mean change in FEV₁ from baseline to month 24 [mean (s.e.m.) 0.037 (0.0119) l; 95% CI 0.014 to 0.060] using mixed‐model repeated‐measure with a pre‐specified non‐inferiority margin of 50 ml/year. After a greater initial decline at month 3 with TI, rate of change (slope) in FEV₁, FVC and DL_CO (months 3–24) was not statistically different between treatment groups. TI was well tolerated; no serious safety concerns emerged. The most common respiratory event associated with TI was mild, transient cough, occurring within minutes of inhalation. Conclusions: Observed changes in lung function with TI were small, occurred early after therapy initiation, remained non‐progressive over 2 years and were unlikely to be clinically meaningful.     

Rac2-MRC-cIII-generated ROS cause genomic instability in chronic myeloid leukemia stem cells and primitive progenitors

Chronic myeloid leukemia in chronic phase (CML-CP) is induced by BCR-ABL1 oncogenic tyrosine kinase. Tyrosine kinase inhibitors eliminate the bulk of CML-CP cells, but fail to eradicate leukemia stem cells (LSCs) and leukemia progenitor cells (LPCs) displaying innate and acquired resistance, respectively. These cells may accumulate genomic instability, leading to disease relapse and/or malignant progression to a fatal blast phase. In the present study, we show that Rac2 GTPase alters mitochondrial membrane potential and electron flow through the mitochondrial respiratory chain complex III (MRC-cIII), thereby generating high levels of reactive oxygen species (ROS) in CML-CP LSCs and primitive LPCs. MRC-cIII-generated ROS promote oxidative DNA damage to trigger genomic instability, resulting in an accumulation of chromosomal aberrations and tyrosine kinase inhibitor-resistant BCR-ABL1 mutants. JAK2(V617F) and FLT3(ITD)-positive polycythemia vera cells and acute myeloid leukemia cells also produce ROS via MRC-cIII. In the present study, inhibition of Rac2 by genetic deletion or a small-molecule inhibitor and down-regulation of mitochondrial ROS by disruption of MRC-cIII, expression of mitochondria-targeted catalase, or addition of ROS-scavenging mitochondria-targeted peptide aptamer reduced genomic instability. We postulate that the Rac2-MRC-cIII pathway triggers ROS-mediated genomic instability in LSCs and primitive LPCs, which could be targeted to prevent the relapse and malignant progression of CML.     

Performance of the integrated management of childhood illness algorithm for diagnosis of HIV-1 infection among African infants

OBJECTIVES:: Early infant HIV-1 diagnosis and treatment substantially improve survival. Where virologic HIV-1 testing is unavailable, integrated management of childhood illness (IMCI) clinical algorithms may be used for infant HIV-1 screening. We evaluated the performance of the 2008 WHO IMCI HIV algorithm in a cohort of HIV-exposed Kenyan infants. METHODS:: From 1999 to 2003, 444 infants had monthly clinical assessments and quarterly virologic HIV-1 testing. Using archived clinical data, IMCI sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated using virologic testing as a gold standard. Linear regression and survival analyses were used to determine the effect of age on IMCI performance and timing of diagnosis. RESULTS:: Overall IMCI sensitivity, specificity, PPV, and NPV value were 58, 87, 52, and 90%, respectively. Sensitivity (1.4%) and PPV (14%) were lowest at 1 month of age, when 81% of HIV infections already had occurred. Sensitivity increased with age (P?相似文献