Objective
Although the majority of the ATP in chondrocytes is made by glycolysis rather than by oxidative phosphorylation in mitochondria there is evidence to suggest that reactive oxygen species produced by mitochondrial electron transport help to maintain cellular redox balance in favor of glycolysis. The objective of this study was to test this hypothesis by determining if rotenone, which inhibits electron transport and blocks oxidant production inhibits glycolytic ATP synthesis.
Design
Bovine osteochondral explants were treated with rotenone, an electron transport inhibitor; or oligomycin an ATP synthase inhibitor; or 2-fluoro-2-deoxy-D-glucose, a glycolysis inhibiter; or peroxide, an exogenous oxidant; or mitoquinone, a mitochondria-targeted anti-oxidant. Cartilage extracts were assayed for ATP, NAD+, and NADH, and culture medium was assayed for pyruvate and lactate after 24 hours of treatment. Imaging studies were used to measure superoxide production in cartilage.
Results
Rotenone and 2-fluoro-2-deoxy-D-glucose caused a significant decline in cartilage ATP (p < 0.001). In contrast, ATP levels were not affected by oligomycin. Peroxide treatment blocked rotenone effects on ATP, while treatment with MitoQ significantly suppressed ATP levels. Rotenone and 2-fluoro-2-deoxy-D-glucose caused a significant decline in pyruvate, but not in lactate production. NADH:NAD+ ratios decreased significantly in both rotenone and 2-fluoro-2-deoxy-D-glucose-treated explants (p < 0.05). Rotenone also significantly reduced superoxide production
Conclusions
These findings showing a link between glycolysis and electron transport are consistent with previous reports on the critical need for oxidants to support normal chondrocyte metabolism. They suggest a novel role for mitochondria in cartilage homeostasis that is independent of oxidative phosphorylation.
HighlightsObturator hernias are rare and may have increased morbidity in the presence of a hip disarticulation due to altered anatomy.Obturator hernias after an ipsilateral hip disarticulation can be treated through the reduction of bowel and hernia repair with mesh.A high index of suspicion is necessary for early diagnosis and prompt surgical intervention, along with appropriate education for healthcare providers and patients.
Objective:Low-velocity gunshot wounds (LV-GSWs) are a common reason for emergency department visits. Optimal nonsurgical treatment has not been thoroughly studied and is not standardized. The goal of this study was to determine whether positive pressure irrigation reduces the bacterial contamination after a simulated GSW to soft tissue.Methods:Nineteen lamb shank specimens were prepared with denim inoculated with Serratia marcescens cultures. A 9-mm pistol round was fired from a distance of 3 m through the contaminated denim into the lamb shank. A culture swab was placed in the wound directly after firing, after 250 cubic-centimeters (cc) irrigation with normal saline, and after an additional 250 cc irrigation (for a total of 500 cc). Swabs were then cultured to determine the amount of bacterial growth.Results:Before irrigation, 0 (0%) plates showed no growth, 2 (10.5%) showed rare growth, 8 (42.1%) showed few growth, 6 (31.6%) showed moderate growth, and 3 (15.8%) showed many growth. After 500 cc irrigation, 2 (10.5%) showed no growth, 1 (5.3%) showed rare growth, 11 (57.9%) showed few growth, 2 (10.5%) showed moderate growth, and 3 (15.8%) showed many growth. Fisher exact test confirmed no significant change in bacterial concentration after irrigation (P = 0.59). A Pearson test found no correlation between irrigation and bacterial growth (r = −0.15, P = −0.25).Conclusions:Positive pressure irrigation with up to 500 cc normal saline did not significantly alter the quantity of bacterial growth within a simulated GSW cavity. The data suggest that bedside positive pressure irrigation may not be beneficial in the initial emergency department treatment of LV-GSWs.
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