1 Department of Pediatrics, 2 Institute of Environmental Health Sciences, 3 Department of Pathology, Wayne State University and John D. Dingell Veterans Hospital, Detroit, Michigan
Submitted 13 July ...2005
; accepted in final form 10 March 2006
Anthracyclines are antitumor agents the main clinical limitation of which is cardiac toxicity. The mechanism of this cardiotoxicity is thought to be related to generation of oxidative stress, causing lethal injury to cardiac myocytes. Although protein and lipid oxidation have been documented in anthracycline-treated cardiac myocytes, DNA damage has not been directly demonstrated. This study was undertaken to determine whether anthracyclines induce cardiac myocyte DNA damage and whether this damage is linked to a signaling pathway culminating in cell death. H9c2 cardiac myocytes were treated with the anthracycline doxorubicin at clinically relevant concentrations, and DNA damage was assessed using the alkaline comet assay. Doxorubicin induced DNA damage, as shown by a significant increase in the mean tail moment above control, an effect ameliorated by inclusion of a free radical scavenger. Repair of DNA damage was incomplete after doxorubicin treatment in contrast to the complete repair observed in H 2 O 2 -treated myocytes after removal of the agent. Immunoblot analysis revealed that p53 activation occurred subsequent in time to DNA damage. By a fluorescent assay, doxorubicin induced loss of mitochondrial membrane potential after p53 activation. Chemical inhibition of p53 prevented doxorubicin-induced cell death and loss of mitochondrial membrane potential without preventing DNA damage, indicating that DNA damage was proximal in the events leading from doxorubicin treatment to cardiac myocyte death. Specific doxorubicin-induced DNA lesions included oxidized pyrimidines and 8-hydroxyguanine. DNA damage therefore appears to play an important early role in anthracycline-induced lethal cardiac myocyte injury through a pathway involving p53 and the mitochondria.
anthracycline; p53; comet assay; deoxyribonucleic acid damage; mitochondrial membrane potential; oxidative stress
Address for reprint requests and other correspondence: T. L. L'Ecuyer, Cardiology Division, Children's Hospital of Michigan, Detroit, MI 48201 (e-mail: thlecuye{at}med.wayne.edu )
Tumor/host-generated thrombin (endogenous thrombin) was investigated with tumor growth and metastasis experiments in mice by the use of hirudin, a highly potent specific inhibitor of thrombin. ...Pretreatment with hirudin inhibited tumor implantation in nude or syngeneic mice, following subcutaneous injection of 2 human and 2 murine tumors. Hirudin induced a considerable lag period in the appearance of tumor growth, compared with phosphate-buffered saline (PBS) treatment, but had no effect on established tumor nodule growth in vivo or on tumor growth in vitro. Hirudin treatment induced central necrosis of the tumor nodule compared with no effect with PBS treatment. Greater protection was noted with longer duration of treatment. Tumor seeding into blood was examined with green fluorescent protein (GFP)-labeled tumor cells. Hirudin inhibited seeding into the blood as well as systemic organs which varied from complete protection to 15- to 32-fold in the blood and 17- to 395-fold in the lung. Hirudin inhibited spontaneous metastases from subcutaneously implanted tumor by reducing the number of tumor nodules in the lungs. Mouse survival in animals injected subcutaneously with highly aggressive 4T1 cells revealed 5 of 5 deaths of PBS-treated animals on day 40 compared with no deaths with hirudin treatment, with prolongation of survival with hirudin treatment of 16 days to more than 31 days. Thus, endogenous thrombin contributes to tumor implantation, seeding, and spontaneous metastasis. A potent antithrombin agent should be of clinical benefit to patients with cancer. (Blood. 2004;104:2746-2751)
Although myeloma light chains are known to undergo receptor-mediated endocytosis in the kidney, the molecular identity of the receptor has not been characterized. We examined the interaction between ...cubilin (gp280) and four species of light chains isolated from the urine of patients with multiple myeloma. Four lines of evidence identify cubilin, a giant glycoprotein receptor, which is restricted in distribution to endocytic scavenger pathways and which has potent effects on endosomal trafficking, as a potentially physiologically relevant binding site for light chains: 1) light chains coeluted during immunoaffinity purification of cubilin; 2) polyclonal antisera to cubilin but not control sera, displaced human light chain binding from rat renal brush-border membranes; 3) cubilin bound to multiple species of light chains during surface plasmon resonance; 4) anti-cubilin antiserum interfered with light chain endocytosis by visceral yolk sac epithelial cells. However, both binding of light chains to brush-border membranes and endocytosis of light chains by yolk sac epithelial cells were only partially inhibited by anticubilin antibodies, suggesting presence of additional or alternate binding sites for light chains. Excess light chain had a potent inhibitory effect on endosomal fusion in vitro. Binding showed dose and time-dependent saturability with low-affinity, high-capacity equilibrium binding parameters. These data demonstrate that cubilin plays a role in the endocytosis and trafficking of light chains in renal proximal tubule cells.
Very young children with type 1 diabetes often struggle to achieve glycemic targets, putting them at risk for long-term complications and creating an immense management burden for caregivers. We ...conducted the first evaluation of the Omnipod 5 Automated Insulin Delivery System in this population.
A total of 80 children aged 2.0-5.9 years used the investigational system in a single-arm study for 13 weeks following 14 days of baseline data collection with their usual therapy.
There were no episodes of severe hypoglycemia or diabetic ketoacidosis. By study end, HbA1c decreased by 0.55% (6.0 mmol/mol) (P < 0.0001). Time with sensor glucose levels in target range 70-180 mg/dL increased by 10.9%, or 2.6 h/day (P < 0.0001), while time with levels <70 mg/dL declined by median 0.27% (P = 0.0204).
Use of the automated insulin delivery system was safe, and participants experienced improved glycemic measures and reduced hypoglycemia during the study phase compared with baseline.
South Carolina has one of the fastest-growing Hispanic/Latino populations in the United States, and the majority of the immigrants are of Mexican descent. Historically, most of these immigrants were ...young men, but in recent years, more women and children have moved from Mexico to South Carolina and other parts of the Southeast. The study presented here investigated the lives of 20 undocumented Mexican women in South Carolina using a grounded theory approach. It found that undocumented women from Mexico have mustered a tremendous amount of strength and resilience in overcoming the cultural, social, economic, and legal barriers of living in the United States. The findings suggest that more research is necessary on the resilience and assets that undocumented women from Mexico bring to the United States.
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Background: The fluoropyrimidines (FP), 5-Fluorouracil (5-FU) and capecitabine are a mainstay of colorectal cancer (CRC) treatment. Dihydropyrimidine dehydrogenase (DPYD), an enzyme ...encoded by the DPYD gene, is the initial and rate-limiting step in pyrimidine catabolism, deactivating over 80% of 5-FU. Approximately 5% of the population are deficient in DPYD and can develop severe or fatal FP toxicities. Currently, few national guidelines recommend routine prospective DPYD testing. In July 2019, we commenced a 6 month prospective pilot, testing DPYD status of all CRC patients undergoing first FP treatment in a large regional cancer centre. Methods: All CRC patients eligible for first exposure to FP are tested using a rapid molecular assay screening for five SNPs (detects 70% of DPYD mutations) and we will present data on prevalence of each. We will use electronic chemotherapy prescribing records (July 19-Jan 20) to collect information on dose modifications and toxicities. Once the pilot is completed we will perform a cost-effectiveness analysis. Results: Data from the first 3 months of this pilot have been reviewed and 201 patients have been tested with 15 heterozygotes identified, of which 2 had more than one mutation. No homozygotes were found. All heterozygote patients are started with a dose reduction (or have alternative therapy). One patient treated at 50% dose was hospitalised with several grade 3 toxicities despite dose reduction. Two patients have had subsequent dose escalation (by 25%). Nine patients have received one dose reduced cycle without complication. Three patients are due to start dose-reduced treatment. Conclusions: Routine prospective testing of DPYD status in a large regional cancer centre is feasible and with a sufficiently swift result turnaround to permit up-front dose modification. Detailed toxicity analysis and cost-effectiveness data will be presented.
The speed and availability of Internet-capable devices, such as computers, smartphones, gaming consoles, TVs, and tablets have made it possible for our society to be connected, and stay connected to ...the Internet 24 hours a day. The Internet of Things (IoT) describes a new environment where common objects are uniquely identifiable and accessible via the Internet. It is estimated that more than 50 billion objects will be connected to the Internet by 2020. Many traditional colleges and universities have discovered the benefits of deploying IoT technology on their campuses. The deployment of IoT devices in traditional colleges and universities may provide opportunities to expand content delivery and enhance learner and faculty interaction. However, if not implemented appropriately, IoT devices have the potential to jeopardize the confidentiality, integrity, and availability of campus resources. The number of objects connected to the Internet increases the number of campus vulnerabilities and subsequently, increases the risk of campus exploitation and attack. In this qualitative study, the researcher investigated the impact of the Internet of Things (IoT) on the IT security infrastructure of traditional colleges and universities in the State of Utah. This study was conducted using survey research. The study investigated the uses of IoT technology in traditional colleges and universities, the security risks of IoT devices in traditional colleges and universities, and the changes IoT technology had on the IT infrastructure of traditional colleges and universities. The data collected in this study originated from an online survey distributed to 24 traditional colleges and universities in the State of Utah. The study found that the IoT implementations precipitated changes to the campus IT infrastructures, including closed and isolated networks. Fifty-five percent of the colleges and universities reported that they separate the IoT data from the structured data. The separation is accomplished either virtually, via virtual local area networks (VLANs) or by physical network isolation. The IoT redefined IT security management. One hundred percent of the 11 colleges and universities were required to change the way they manage network security after their IoT implementation. The management of the Internet of Things is now a shared responsibility between the operations (facilities) technology and information technology departments. Although the number of risks did not increase, the category of risks changed after the IoT implementations. Fifty-five percent of the schools reported that the top risk after the IoT deployment was the release of personally identifiable information. The findings revealed that traditional colleges and universities in Utah are aware of the challenges and risks of the Internet of Things and have initiated strategies for mitigation. The recommendation for future research is to extend the concepts of the current study to conduct a qualitative grounded theory research study (Glaser & Strauss, 2009). Grounded theory is a good fit for IT research because it is suitable for the investigation of complex events (Jones & Alony, 2011).The study would include a sampling of traditional colleges and universities across the United States to investigate the impact the IoT has IT security management, IT security risks, and the IT infrastructure. The second recommendation for future research is to conduct a grounded theory research study to include a sampling of K-12 schools across the United States. K-12 schools are attractive targets for cyberattacks due to the amount of data they collect, including academic records, attendance records, and medical history (Lestch, 2015). However, many K-12 schools are unprepared for the impact of the Internet of Things due to limitations in budgets, IT support, and bandwidth. The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.
1 Department of Pathology, John D. Dingell Veterans Affairs Medical Center, and Departments of 2 Pathology and 3 Medicine, Wayne State University Medical School, Detroit, Michigan
Submitted 8 ...February 2006
; accepted in final form 8 March 2006
To define better the subcellular mechanism of heat shock (HS)-induced cardioprotection, we examined the effect of HS, as well as selective expression of individual HS proteins (HSPs), on cell injury in neonatal rat ventricular myocytes (NRVM). HS was induced in NRVM by a rapid elevation of temperature to 42°C for 20 min followed by 2024 h of recovery at 37°C. Other NRVM were infected with a replication-deficient adenovirus encoding HSP27 or HSP70. On the same day, all groups were subjected to metabolic inhibition (MI). Cell injury was assayed by measurement of the percentage of total lactate dehydrogenase released, the percentage of cells staining with trypan blue, or TdT-mediated dUTP nick-end labeling, whereas cell signaling was assayed by immunoblot analysis and coimmunoprecipitation. Before MI, the viability of all treated groups did not differ significantly from control NRVM. HS resulted in a significant increase in HSP70 and HSP27 expression. Infection with either virus caused a significant increase in selective HSP content compared with control NRVM. HS protected NRVM from injury. Selective expression of HSP27 or HSP70 alone was not protective in NRVM, but dual infection with both viral vectors (HSP27 + HSP70) was protective. HS and HSP27 + HSP70 expression caused increased paxillin localization in the membrane fraction, which persisted in response to MI, compared with control NRVM. HS increased the integrin-paxillin-focal adhesion kinase interaction, whereas targeted inhibition of focal adhesion kinase activity abolished the integrin-paxillin association and resulted in an increase in cell death. HS and HSP27 + HSP70 expression increased the association of members of the focal adhesion complex and protected NRVM against irreversible injury. Cytoskeletal-based signaling pathways at focal adhesion junctions may represent a unique pathway of cardioprotection.
heat shock protein; neonatal rat ventricular myocytes; metabolic inhibition
Address for reprint requests and other correspondence: R. S. Vander Heide, Dept. of Pathology, Wayne State Univ. Medical School, 540 East Canfield Ave., Detroit, MI 48201 (e-mail: rvanderh{at}med.wayne.edu )
To define better the subcellular mechanism of heat shock (HS)-induced cardioprotection, we examined the effect of HS, as well as selective expression of individual HS proteins (HSPs), on cell injury ...in neonatal rat ventricular myocytes (NRVM). HS was induced in NRVM by a rapid elevation of temperature to 42°C for 20 min followed by 20-24 h of recovery at 37°C. Other NRVM were infected with a replication-deficient adenovirus encoding HSP27 or HSP70. On the same day, all groups were subjected to metabolic inhibition (MI). Cell injury was assayed by measurement of the percentage of total lactate dehydrogenase released, the percentage of cells staining with trypan blue, or TdT-mediated dUTP nick-end labeling, whereas cell signaling was assayed by immunoblot analysis and coimmunoprecipitation. Before MI, the viability of all treated groups did not differ significantly from control NRVM. HS resulted in a significant increase in HSP7O and HSP27 expression. Infection with either virus caused a significant increase in selective HSP content compared with control NRVM. HS protected NRVM from injury. Selective expression of HSP27 or HSP7O alone was not protective in NRVM, but dual infection with both viral vectors (HSP27 + HSP7O) was protective. HS and HSP27 + HSP7O expression caused increased paxillin localization in the membrane fraction, which persisted in response to MI, compared with control NRVM. HS increased the integrin-paxillin-focal adhesion kinase interaction, whereas targeted inhibition of focal adhesion kinase activity abolished the integrin-paxillin association and resulted in an increase in cell death. HS and HSP27 + HSP7O expression increased the association of members of the focal adhesion complex and protected NRVM against irreversible injury. Cytoskeletal-based signaling pathways at focal adhesion junctions may represent a unique pathway of cardioprotection. PUBLICATION ABSTRACT
To define better the subcellular mechanism of heat shock (HS)-induced cardioprotection, we examined the effect of HS, as well as selective expression of individual HS proteins (HSPs), on cell injury ...in neonatal rat ventricular myocytes (NRVM). HS was induced in NRVM by a rapid elevation of temperature to 42 degree C for 20 min followed by 20-24 h of recovery at 37 degree C. Other NRVM were infected with a replication-deficient adenovirus encoding HSP27 or HSP70. On the same day, all groups were subjected to metabolic inhibition (MI). Cell injury was assayed by measurement of the percentage of total lactate dehydrogenase released, the percentage of cells staining with trypan blue, or TdT-mediated dUTP nick-end labeling, whereas cell signaling was assayed by immunoblot analysis and coimmunoprecipitation. Before MI, the viability of all treated groups did not differ significantly from control NRVM. HS resulted in a significant increase in HSP70 and HSP27 expression. Infection with either virus caused a significant increase in selective HSP content compared with control NRVM. HS protected NRVM from injury. Selective expression of HSP27 or HSP70 alone was not protective in NRVM, but dual infection with both viral vectors (HSP27 + HSP70) was protective. HS and HSP27 + HSP70 expression caused increased paxillin localization in the membrane fraction, which persisted in response to MI, compared with control NRVM. HS increased the integrin-paxillin-focal adhesion kinase interaction, whereas targeted inhibition of focal adhesion kinase activity abolished the integrin-paxillin association and resulted in an increase in cell death. HS and HSP27 + HSP70 expression increased the association of members of the focal adhesion complex and protected NRVM against irreversible injury. Cytoskeletal-based signaling pathways at focal adhesion junctions may represent a unique pathway of cardioprotection.
