Download the Free Unbound MEDLINE PubMed App to your smartphone or tablet.
Available for iPhone, iPad, iPod touch, and Android.
- Proline-rich Region of Non-Muscle Myosin Light Chain Kinase Modulates Kinase Activity and Endothelial Cytoskeletal Dynamics. [JOURNAL ARTICLE]
- Microvasc Res 2014 Jul 26.
Disruption of the pulmonary endothelial barrier and subsequent vascular leak is a hallmark of acute lung injury. Dynamic rearrangements in the endothelial cell (EC) peripheral membrane and underlying cytoskeleton are critical determinants of barrier function. The cytoskeletal effector protein non-muscle myosin light chain kinase (nmMLCK) and the actin-binding regulatory protein cortactin are important regulators of the endothelial barrier. In the present study we functionally characterize a proline-rich region of nmMLCK previously identified as the possible site of interaction between nmMLCK and cortactin. A mutant nmMLCK construct deficient in proline residues at the putative sites of cortactin binding (amino acids 973, 976, 1019, 1022) was generated. Co-immunoprecipitation studies in human lung EC transfected with wild-type or mutant nmMLCK demonstrated similar levels of cortactin interaction at baseline and after stimulation with the barrier-enhancing agonist, sphingosine 1-phosphate (S1P). In contrast, binding studies utilizing recombinant nmMLCK fragments containing the wild-type or proline-deficient sequence demonstrated a two fold increase in cortactin binding (p<0.01) to the mutant construct. Immunofluorescent microscopy revealed increased stress fiber density in ECs expressing GFP-labeled mutant nmMLCK at baseline (p=0.02) and after thrombin (p=0.01) or S1P (p=0.02) when compared to wild-type. Mutant nmMLCK demonstrated an increase in kinase activity in response to thrombin (p<0.01). Kymographic analysis demonstrated increased EC membrane retraction distance and velocity (p<0.01) in response to the barrier disrupting agent thrombin in cells expressing the mutant vs. wild-type nmMLCK construct. These results provide evidence that critical prolines within nmMLCK (amino acids 973, 976, 1019, 1022) regulate cytoskeletal and membrane events associated with pulmonary endothelial barrier function.
- Thrombolysis for acute ischaemic stroke. [JOURNAL ARTICLE]
- Cochrane Database Syst Rev 2014 Jul 29.:CD000213.
Most strokes are due to blockage of an artery in the brain by a blood clot. Prompt treatment with thrombolytic drugs can restore blood flow before major brain damage has occurred and improve recovery after stroke in some people. Thrombolytic drugs, however, can also cause serious bleeding in the brain, which can be fatal. One drug, recombinant tissue plasminogen activator (rt-PA), is licensed for use in selected patients within 4.5 hours of stroke in Europe and within three hours in the USA. There is an upper age limit of 80 years in some countries, and a limitation to mainly non-severe stroke in others. Forty per cent more data are available since this review was last updated in 2009.To determine whether, and in what circumstances, thrombolytic therapy might be an effective and safe treatment for acute ischaemic stroke.We searched the Cochrane Stroke Group Trials Register (last searched November 2013), MEDLINE (1966 to November 2013) and EMBASE (1980 to November 2013). We also handsearched conference proceedings and journals, searched reference lists and contacted pharmaceutical companies and trialists.Randomised trials of any thrombolytic agent compared with control in people with definite ischaemic stroke.Two review authors applied the inclusion criteria, extracted data and assessed trial quality. We verified the extracted data with investigators of all major trials, obtaining additional unpublished data if available.We included 27 trials, involving 10,187 participants, testing urokinase, streptokinase, rt-PA, recombinant pro-urokinase or desmoteplase. Four trials used intra-arterial administration, while the rest used the intravenous route. Most data come from trials that started treatment up to six hours after stroke. About 44% of the trials (about 70% of the participants) were testing intravenous rt-PA. In earlier studies very few of the participants (0.5%) were aged over 80 years; in this update, 16% of participants are over 80 years of age due to the inclusion of IST-3 (53% of participants in this trial were aged over 80 years). Trials published more recently utilised computerised randomisation, so there are less likely to be baseline imbalances than in previous versions of the review. More than 50% of trials fulfilled criteria for high-grade concealment; there were few losses to follow-up for the main outcomes.Thrombolytic therapy, mostly administered up to six hours after ischaemic stroke, significantly reduced the proportion of participants who were dead or dependent (modified Rankin 3 to 6) at three to six months after stroke (odds ratio (OR) 0.85, 95% confidence interval (CI) 0.78 to 0.93). Thrombolytic therapy increased the risk of symptomatic intracranial haemorrhage (OR 3.75, 95% CI 3.11 to 4.51), early death (OR 1.69, 95% CI 1.44 to 1.98; 13 trials, 7458 participants) and death by three to six months after stroke (OR 1.18, 95% CI 1.06 to 1.30). Early death after thrombolysis was mostly attributable to intracranial haemorrhage. Treatment within three hours of stroke was more effective in reducing death or dependency (OR 0.66, 95% CI 0.56 to 0.79) without any increase in death (OR 0.99, 95% CI 0.82 to 1.21; 11 trials, 2187 participants). There was heterogeneity between the trials. Contemporaneous antithrombotic drugs increased the risk of death. Trials testing rt-PA showed a significant reduction in death or dependency with treatment up to six hours (OR 0.84, 95% CI 0.77 to 0.93, P = 0.0006; 8 trials, 6729 participants) with significant heterogeneity; treatment within three hours was more beneficial (OR 0.65, 95% CI 0.54 to 0.80, P < 0.0001; 6 trials, 1779 participants) without heterogeneity. Participants aged over 80 years benefited equally to those aged under 80 years, particularly if treated within three hours of stroke.Thrombolytic therapy given up to six hours after stroke reduces the proportion of dead or dependent people. Those treated within the first three hours derive substantially more benefit than with later treatment. This overall benefit was apparent despite an increase in symptomatic intracranial haemorrhage, deaths at seven to 10 days, and deaths at final follow-up (except for trials testing rt-PA, which had no effect on death at final follow-up). Further trials are needed to identify the latest time window, whether people with mild stroke benefit from thrombolysis, to find ways of reducing symptomatic intracranial haemorrhage and deaths, and to identify the environment in which thrombolysis may best be given in routine practice.
- Pharmacokinetic-pharmacodynamic (PK-PD) modeling and simulation of 5-fluorouracil for erythropenia in rats. [JOURNAL ARTICLE]
- J Pharmacol Toxicol Methods 2014 Jul 26.
The aim of the present study was to develop a simple pharmacokinetic-pharmacodynamic (PK-PD) model in rats that could predict the onset and degree of erythropenia, a severely toxic side effect that severely limits the use of the anticancer agent 5-fluorouracil (5-FU) METHODS: Total erythrocyte counts, hemoglobin (Hb) concentrations, and hematocrit (Hct) levels were measured in rats following the intravenous bolus administration of 5-FU for 4days in order to obtain data for an analysis of the PK-PD model. Our PK-PD model consisted of a two-compartment PK model, with two compartments for the PD model and nine structural PK-PD model parameters.After the intravenous bolus administration of 5, 10, or 20mg/kg of 5-FU to rats, absolute erythrocyte counts, Hb concentrations, and Hct levels transiently decreased, reached minimum levels on Days 7-14, and then returned to baseline levels. The nadir values (Cnadir) for rats treated with 5, 10, or 20mg/kg of 5-FU were significantly decreased to approximately 79.4, 76.3, or 46.5% of the baseline value (Cbaseline) in erythrocyte counts, 86.3, 83.3, or 45.7% of Cbaseline in Hb concentrations, 88.6, 85.5, or 47.1% of Cbaseline in Hct levels, respectively. The PK-PD model effectively captured the features of erythropenia and Cnadir after 5-FU chemotherapy. This PK-PD model was successfully used to characterize the learner relationship between the area under the plasma 5-FU concentration-time curve (AUC0-∞) following the intravenous bolus administration of 5-FU and the Cnadir in erythrocyte counts, Hb concentrations, and Hct levels after the 5-FU treatment.The results of the present study suggest that the administration of a pharmacokinetically modified dose of 5-FU could minimize the Cnadir in erythrocyte counts, Hb concentrations, and Hct levels following the administration of 5-FU. The PK-PD model and simulation represent valuable approaches for quantifying and predicting erythropenia as well as determining individual doses and the time at which the subsequent course of the treatment should start.
- In Vivo Detection of Macrophage Recruitment in Hind-Limb Ischemia Using a Targeted Near-Infrared Fluorophore. [JOURNAL ARTICLE]
- PLoS One 2014; 9(7):e103721.
Macrophages are an essential component of the immune system and have protective and pathogenic functions in various diseases. Imaging of macrophages in vivo could furnish new tools to advance evaluation of disease and therapies. Critical limb ischemia is a disease in which macrophages have considerable pathogenic roles, and are potential targets for cell-based immunotherapy. We sought to develop a new near-infrared fluorescence (NIRF) imaging probe to target macrophages specifically in vivo in various pathological states, including hind-limb ischemia. We rapidly screened the photostable cyanine-based NIRF library against different blood cell lines. The identified monocyte/macrophage-selective hit was tested in vitro in live-cell labeling assay. Non-invasive NIRF imaging was performed with murine models of paw inflammation by lipopolysaccharide challenge and hind-limb ischemia with femoral artery ligation. in vivo macrophage targeting was further evaluated using intravital microscopy with Csf1r-EGFP transgenic mice and immunofluorescent staining with macrophage-specific markers. We discovered MF800, a Macrophage-specific near-infrared Fluorophore, which showed selective live-cell imaging performance in a panel of cell lines and primary human blood samples. MF800 outperforms the clinically-available NIRF contrast agent ICG for in vivo specificity in paw inflammation and hind-limb ischemia models. We observed a marked overlap of MF800-labeled cells and EGFP-expressing macrophages in intravital imaging of Csf1r-EGFP transgenic mice. In the histologic analysis, MF800-positive cells also expressed the macrophage markers CD68 and CD169. NIRF imaging showcased the potential of using MF800 to understand macrophage behavior in vivo, characterize macrophage-associated diseases, and may help in assessing therapeutic responses in the clinic.
- Invasive Fungal Infections in Children With Hematologic and Malignant Diseases. [JOURNAL ARTICLE]
- J Pediatr Hematol Oncol 2014 Jul 28.
To evaluate the clinical feature and outcome of invasive fungal infections (IFI) in children with hematologic and malign diseases.The medical records of children with hematologic and malignant diseases, who were hospitalized at our hospital between January 2010 and December 2011, were reviewed. Proven, probable, and possible IFIs were diagnosed according to the revised definitions of the European Organization for Research and Treatment of Cancer/Mycosis Study Group. The demographic, clinical, and laboratory characteristics of the patients who met the study criteria were evaluated.IFI was diagnosed in 67 (7.2%) febrile episodes of 56 patients, of which 10 (1.2%) were proven, 20 (2%) probable, and 37 (4%) possible IFI. Blood culture of 10 cases with proven IFI yielded yeast and the most common isolated agent was Candida parapsilosis. Seventy percent of cases with fungemia had central venous catheter (CVC). Twenty cases with probable IFI had invasive mold infection. The cases with mold infection had higher median C-reactive protein values, lower neutrophil counts, and longer duration of neutropenia compared with the cases with yeast infection. A total of 14 patients (20.9%) died. Presence of CVC, bone marrow transplantation, total parenteral nutrition, prolonged fever, and proven/probable IFI were detected more often in patients who died, compared with patients who survived.IFIs are important causes of death in children with hematologic and malignant diseases. Mold infections are seen more frequently in cases with prolonged and profound neutropenia, and invasive yeast infections, especially with non-albicans Candida species, in cases with CVC. Early and effective treatment considering these findings will help to decrease the mortality.
- The role of biological therapy in metastatic colorectal cancer after first-line treatment: a meta-analysis of randomised trials. [JOURNAL ARTICLE]
- Br J Cancer 2014 Jul 29.
Purpose:Biologic agents have achieved variable results in relapsed metastatic colorectal cancer (mCRC). Systematic meta-analysis was undertaken to determine the efficacy of biological therapy.Methods:Major databases were searched for randomised studies of mCRC after first-line treatment comparing (1) standard treatment plus biologic agent with standard treatment or (2) standard treatment with biologic agent with the same treatment with different biologic agent(s). Data were extracted on study design, participants, interventions and outcomes. Study quality was assessed using the MERGE criteria. Comparable data were pooled for meta-analysis.Results:Twenty eligible studies with 8225 patients were identified. The use of any biologic therapy improved overall survival with hazard ratio (HR) 0.87 (95% confidence interval (CI) 0.82-0.91, P<0.00001), progression-free survival (PFS) with HR 0.71 (95% CI 0.67-0.74, P<0.0001) and overall response rate (ORR) with odds ratio (OR) 2.38 (95% CI 2.03-2.78, P<0.00001). Grade 3/4 toxicity was increased with OR 2.34. Considering by subgroups, EGFR inhibitors (EGFR-I) in the second-line setting and anti-angiogenic therapies (both in second-line and third-line and beyond settings) all improved overall survival, PFS and ORR. EGFR-I in third-line settings improved PFS and ORR but not OS.Conclusions:The use of biologic agents in mCRC after first-line treatment is associated with improved outcomes but increased toxicity.British Journal of Cancer advance online publication, 29 July 2014; doi:10.1038/bjc.2014.404 www.bjcancer.com.
- Mycobacterium Biofilms: Factors Involved in Development, Dispersal, and Therapeutic Strategies Against Biofilm-Relevant Pathogens. [JOURNAL ARTICLE]
- Crit Rev Eukaryot Gene Expr 2014; 24(3):269-279.
Many bacteria can develop biofilm (BF), a multicellular structure largely combining bacteria and their extracellular polymeric substances (EPS). The formation of biofilm results in an alternative existence in which microbes ensure their survival in adverse environments. Biofilm-relevant infections are more persistent, resistant to most antibiotics, and more recalcitrant to host immunity. Mycobacterium tuberculosis, the causative agent of tuberculosis, can develop biofilm, though whether M. tuberculosis can form biofilm within tuberculosis patients has yet to be determined. Here, we summarize the factors involved in the development and dispersal of mycobacterial biofilms, as well as underlying regulatory factors and inhibitors against biofilm to deepen our understanding of their development and to elucidate potential novel modes of action for future antibiotics. Key factors in biofilm formation identified as drug targets represent a novel and promising avenue for developing better antibiotics.
- Current Systemic Therapies for Melanoma. [JOURNAL ARTICLE]
- Dermatol Surg 2014 Jul 28.
Systemic agents are used in melanoma for adjuvant therapy and to treat metastatic disease. Currently, interferon-α is the only agent approved for adjuvant therapy. Six drugs are FDA approved for metastatic disease: dacarbazine, interleukin-2 (IL-2), vemurafenib, ipilimumab, dabrafenib, and trametinib. Vemurafenib and ipilimumab were approved in 2011, whereas dabrafenib and trametinib were approved in 2013.This review will update the practicing dermatologist on the differences in efficacy, adverse events, and cost of systemic therapies available for the treatment of melanoma.This article is a review of the current literature on systemic therapies for advanced melanoma. Key search words included "advanced melanoma," "systemic therapy," and "adjuvant therapy" with particular focus on the past 20 years.Before 2011, dacarbazine and IL-2 were the only FDA approved therapies for metastatic melanoma, and IFN-α is the only approved agent for adjuvant therapy. The new agents vemurafenib, ipilimumab, dabrafenib, and trametinib are the first to have improved overall survival in Phase III studies in comparison with other systemic therapies.Despite new developments, there remains a significant need for better therapies with improved long-term efficacy and decreased toxicity.
- Inhibition of notch signaling in combination with Paclitaxel reduces platinum-resistant ovarian tumor growth. [Journal Article]
- Front Oncol 2014.:171.
Ovarian cancer (OvCa) is the most lethal gynecologic malignancy in the United States because of chemoresistant recurrent disease. Our objective was to investigate the efficacy of inhibiting the Notch pathway with a γ-secretase inhibitor (GSI) in an OvCa patient-derived xenograft model as a single agent therapy and in combination with standard chemotherapy.Immunocompromised mice bearing xenografts derived from clinically platinum-sensitive human ovarian serous carcinomas were treated with vehicle, GSI (MRK-003) alone, paclitaxel and carboplatin (P/C) alone, or the combination of GSI and P/C. Mice bearing platinum-resistant xenografts were given GSI with or without paclitaxel. Gene transcript levels of the Notch pathway target Hes1 were analyzed using RT-PCR. Notch1 and Notch3 protein levels were evaluated. The Wilcoxon rank-sum test was used to assess significance between the different treatment groups.Expression of Notch1 and 3 was variable. GSI alone decreased tumor growth in two of three platinum-sensitive ovarian tumors (p < 0.05), as well as in one of three platinum-sensitive tumors (p = 0.04). The combination of GSI and paclitaxel was significantly more effective than GSI alone and paclitaxel alone in all platinum-resistant ovarian tumors (all p < 0.05). The addition of GSI did not alter the effect of P/C in platinum-sensitive tumors. Interestingly, although the response of each tumor to chronic GSI exposure did not correlate with its endogenous level of Notch expression, GSI did negatively affect Notch signaling in an acute setting.Inhibiting the Notch signaling cascade with a GSI reduces primary human xenograft growth in vivo. GSI synergized with conventional cytotoxic chemotherapy only in the platinum-resistant OvCa models with single agent paclitaxel. These findings suggest inhibition of the Notch pathway in concert with taxane therapy may hold promise for treatment of platinum-resistant OvCa.
- Concurrent radiotherapy with Carboplatin and cetuximab for the treatment of medically compromised patients with locoregionally advanced head and neck squamous cell carcinoma. [Journal Article]
- Front Oncol 2014.:165.
Cetuximab (Cx) + radiation therapy (RT) is well-tolerated and has improved survival in patients (pts) with locoregionally advanced head and neck squamous cell carcinomas (LA-HNSCC). However, its efficacy when compared to HD-DDP + RT has been questioned. At our institution, low-dose weekly carboplatin is added to Cx + RT for patients unsuitable for HD-DDP.We reviewed records of 16 patients with LA-HNSCC treated with definitive Cx + carboplatin + RT at the University of Miami from 2007 to 2011. Median follow-up was 24 months (range: 1-69 months).Median age: 71.5 years (range: 57-90 years); 15 male, 1 female. ECOG PS 0 = 15, 1 = 1. TNM staging was: T 1 = 1, T 2 = 5, T 3 = 8, T 4 = 2; N stage: N 0 = 8, N 1 = 5, N 2a = 2, N 2b = 1. All patients received weekly carboplatin (AUC 1.5-2), Cx given conventionally and daily conventionally fractionated RT. Median total weeks of concurrent systemic therapy = 7 (range: 3-8 weeks). RT was delivered to a median total dose of 70 Gy (range 30-74 Gy). Of the 15 evaluable patients, there were: 12 CR, 2 PR, and 1 PD. There were three local in-field failures, two regional failures, and three distant failures. At last follow-up, 8/15 patients remained with NED. Three-year locoregional recurrence was 28.3% (95% CI: 7.7-53.9%). Mean percentage of weight loss was 14% (range: 6-26%). Two patients required systemic therapy dose reduction. Three patients experienced a treatment delay and three did not finish RT as planned including a patient who received only 30 Gy due to death secondary to MI during treatment.In this small retrospective series, carboplatin/Cx/RT was well-tolerated and efficacious in patients unsuitable for HD-DDP having LA-HNSCC. Acute toxicities were similar to Cx + RT, likely due to the non-overlapping toxicity profiles of the two systemic agents. We hypothesize that the addition of a well-tolerated cytotoxic chemotherapy agent may improve the therapeutic ratio of Cx + RT in patients who are poor candidates for more aggressive therapies and warrants evaluation in a prospective manner.