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Biomedical subjects

M Kent Froberg

Publications and source records attributed to M Kent Froberg.

6 recordsLinked to original sources

Somatic mitochondrial DNA mutations in prostate cancer and normal appearing adjacent glands in comparison to age-matched prostate samples without malignant histology.

Studies of somatic mitochondrial DNA mutations have become an important aspect of cancer research because these mutations might have functional significance and/or serve as a biosensor for tumor detection. Here we report somatic mitochondrial DNA mutations from three specific tissue types (tumor, adjacent benign, and distant benign) recovered from 24 prostatectomy samples. Needle biopsy tissue from 12 individuals referred for prostate biopsy, yet histologically benign (symptomatic benign), were used as among individual control samples. We also sampled blood (germplasm tissue) from each patient to serve as within individual controls relative to the somatic tissues sampled (malignant, adjacent, and distant benign). Complete mitochondrial genome sequencing was attempted on each sample. In contrast to both control groups [within patient (blood) and among patient (symptomatic benign)], all of the tissue types recovered from the malignant group harbored significantly different mitochondrial DNA (mtDNA) mutations. We conclude that mitochondrial genome mutations are an early indicator of malignant transformation in prostate tissue. These mutations occur well before changes in tissue histo-pathology, indicative of prostate cancer, are evident to the pathologist.

Aged↗

Murine cytomegalovirus infection markedly reduces serum MCP-1 levels in MCP-1 transgenic mice.

Monocyte chemoattractant protein-1 (MCP-1) is a pro-inflammatory chemokine believed to play a major role in atherogenesis. Injured endothelial cells express MCP-1, which attracts monocytes to the blood vessel wall and leads to the formation of atheromas. Cytomegalovirus infection may also play a role in atherogenesis and accelerates inflammation in tissues that overexpress MCP-1. To examine the relationship of cytomegalovirus infection and MCP-1, we infected MCP-1 transgenic mice with murine cytomegalovirus (MCMV) and collected serum 6 days post-infection to evaluate TH1-related cytokine levels by ELISA. Serum levels of IL-10, IL-12 and IFN-gamma were increased in MCP-1 transgenic mice on day 6 following MCMV infection, while levels of IL-1beta and TNF-alpha were undetectable. However, MCP-1 serum levels were reduced >50% in MCP-1 transgenic mice following MCMV infection compared to uninfected transgenic mice. This effect was not as dramatic when an M33 null MCMV was administered to MCP-1 transgenic mice. The mechanism by which MCMV lowers serum MCP-1 levels is unknown, but this effect may enhance the survival of the virus and thus allow CMV to contribute to the chronic inflammation of atherogenesis.

Animals↗

Carvedilol-mediated antioxidant protection against doxorubicin-induced cardiac mitochondrial toxicity.

The cardiotoxicity associated with doxorubicin (DOX) therapy limits the total cumulative dose and therapeutic success of active anticancer chemotherapy. Cardiac mitochondria are implicated as primary targets for DOX toxicity, which is believed to be mediated by the generation of highly reactive free radical species of oxygen from complex I of the mitochondrial electron transport chain. The objective of this study was to determine if the protection demonstrated by carvedilol (CV), a beta-adrenergic receptor antagonist with strong antioxidant properties, against DOX-induced mitochondrial-mediated cardiomyopathy [Toxicol. Appl. Pharmacol. 185 (2002) 218] is attributable to its antioxidant properties or its beta-adrenergic receptor antagonism. Our results confirm that DOX induces oxidative stress, mitochondrial dysfunction, and histopathological lesions in the cardiac tissue, all of which are inhibited by carvedilol. In contrast, atenolol (AT), a beta-adrenergic receptor antagonist lacking antioxidant properties, preserved phosphate energy charge but failed to protect against any of the indexes of DOX-induced oxidative mitochondrial toxicity. We therefore conclude that the cardioprotective effects of carvedilol against DOX-induced mitochondrial cardiotoxicity are due to its inherent antioxidant activity and not to its beta-adrenergic receptor antagonism.

Adrenergic beta-Antagonists↗

Staphylococcus aureus and Clostridium difficile cause distinct pseudomembranous intestinal diseases.

We report simultaneous infections with Clostridium difficile and methicillin-resistant Staphylococcus aureus (MRSA) in a patient with discrete colonic pseudomembranes typical of C. difficile infection, as well as confluent, loosely adherent pseudomembranes in the small bowel. Identification of MRSA in the small bowel pseudomembrane by polymerase chain reaction supports S. aureus as an enteric pathogen.

Clostridioides difficile↗

Review: CMV escapes!

Cytomegalovirus (CMV) is an opportunistic pathogen that establishes life-long latent infection without clinical disease in immunocompetent individuals, but can cause severe illness in newborns, transplant recipients, and patients with HIV. CMV has evolved complex molecular mechanisms to avoid host immune detection and destruction. Collectively these mechanisms have been termed "immunoevasion" or "escapology." Perhaps the most essential mechanism of virus survival within the host is latency, a form of reversible nonproductive infection of host cells by replication-competent virus. During periods of active virus replication, however, there are multiple strategies by which CMV evades host defenses. These include methods referred to as camouflage, which aid the virus in hiding from immune defenses, and those referred to as sabotage, whereby the virus disrupts or manipulates host inflammatory or immune responses. The ultimate pathogen survival strategy, host cell transformation, has been demonstrated in vitro for CMV, but to date has not been demonstrated in vivo. This review surveys the current literature on CMV immunoevasion and suggests a paradigm whereby CMV survives host defenses and contributes to atherogenesis.

Animals↗