Decompression sickness (DCS) is a systemic disorder, assumed due to gas bubbles, but additional factors are likely to play a role. Circulating microparticles (MPs)--vesicular structures with diameters of 0.1-1.0 μm--have been implicated, but data in human divers have been lacking. We hypothesized that the number of blood-borne, Annexin V-positive MPs and neutrophil activation, assessed as surface MPO staining, would differ between self-contained underwater breathing-apparatus divers suffering from DCS vs. asymptomatic divers. Blood was analyzed from 280 divers who had been exposed to maximum depths from 7 to 105 meters; 185 were control/asymptomatic divers, and 90 were diagnosed with DCS. Elevations of MPs and neutrophil activation occurred in all divers but normalized within 24 h in those who were asymptomatic. MPs, bearing the following proteins: CD66b, CD41, CD31, CD142, CD235, and von Willebrand factor, were between 2.4- and 11.7-fold higher in blood from divers with DCS vs. asymptomatic divers, matched for time of sample acquisition, maximum diving depth, and breathing gas. Multiple logistic regression analysis documented significant associations (P < 0.001) between DCS and MPs and for neutrophil MPO staining. Effect estimates were not altered by gender, body mass index, use of nonsteroidal anti-inflammatory agents, or emergency oxygen treatment and were modestly influenced by divers' age, choice of breathing gas during diving, maximum diving depth, and whether repetitive diving had been performed. There were no significant associations between DCS and number of MPs without surface proteins listed above. We conclude that MP production and neutrophil activation exhibit strong associations with DCS.

Diabetic patients undergoing hyperbaric oxygen treatments (HBO2) for refractory lower extremity neuropathic ulcers exhibit more than a 2-fold elevation (p=0.004) in circulating stem cells after treatments and the post-HBO2 CD34+ cell population contains 2 to 3-fold higher levels of hypoxia inducible factors (HIF)-1, -2 and -3, as well as thioredoxin-1 (p≤0.003) than cells present in blood prior to HBO2. Skin margins obtained from two day old abdominal wounds exhibit higher expression of CD133, CD34, HIF-1 and Trx-1 versus margins from refractory lower extremity wounds and expression of these proteins in all wounds is increased due to HBO2 treatment (p≤0.003). HBO2 is known to mobilize bone marrow stem cells by stimulating nitric oxide synthase (NOS). We found that NOS activity is acutely increased in patient's platelets following HBO2 and remains elevated for at least 20 hours. We conclude that HBO2 stimulates vasculogenic stem cell mobilization from bone marrow of diabetics and more cells are recruited to skin wounds.

BackgroundCarbon monoxide (CO) poisoning is the leading cause of poisoning mortality and morbidity in the USA. Carboxyhemoglobin (COHb) levels are not predictive of severity or prognosis. At this time, the measurement of mitochondrial respiration may serve as a biomarker in CO poisoning. The primary objective of this study was to assess changes in mitochondrial function consisting of respiration and generation of reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMCs) obtained from patients with CO poisoning.MethodsPBMCs from patients having confirmed CO exposure treated with hyperbaric oxygen or HBO (CO group) and healthy controls (control group) were analyzed with high-resolution respirometry. PBMCs were placed in a 2-ml chamber at a final concentration of 3–4 × 106 cells/ml to simultaneously obtain both respiration and hydrogen peroxide (H2O2) production. In the CO group, we performed measurements before and after patients underwent their first HBO treatment.ResultsWe enrolled a total of 17 subjects, including 7 subjects with confirmed CO poisoning and 10 subjects in the control group. The CO group included five (71.4%) men and two (28.6%) women having a median COHb of 28%. There was a significant decrease in respiration as measured in pmol O2 × s− 1 × 10− 6 PBMCs in the CO group (pre-HBO) when compared to the control group: maximal respiration (18.4 ± 2.4 versus 35.4 ± 2.8, P < 0.001); uncoupled Complex I respiration (19.8 ± 1.8 versus 41.1 ± 3.8, P < 0.001); uncoupled Complex I + II respiration (32.3 ± 3.2 versus 58.3 ± 3.1, P < 0.001); Complex IV respiration (43.5 ± 2.9 versus 63.6 ± 6.31, P < 0.05). There were also similar differences measured in the CO group before and after HBO treatment with an overall increase in respiration present after treatment. We also determined the rate of H2O2 production simultaneously with the measurement of respiration. There was an overall significant increase in the H2O2 production in the CO group after HBO treatment when compared to prior HBO treatment and the control group.ConclusionsIn this study, PBMCs obtained from subjects with CO poisoning have an overall decrease in respiration (similar H2O2 production) when compared to controls. The inhibition of Complex IV respiration is from CO binding leading to a downstream decrease in respiration at other complexes. PBMCs obtained from CO-poisoned individuals immediately following initial HBO therapy displayed an overall increase in both respiration and H2O2 production. The study findings demonstrate that treatment with HBO resulted in improved cellular respiration but a higher H2O2 production. It is unclear if the increased production of H2O2 in HBO treatment is detrimental.

We have investigated the isozymes of a phosphoinositide‐specific phospholipase C (PLC) in bovine retina using several monoclonal antisera to PLCβ1, γ1, and δ1. Immunoblot analysis showed that all three isozymes were present in the retina. Immunocytochemical localization in frozen bovine retina sections showed that PLCγ1 was present in the photoreceptor cell layer, outer plexiform cell layer, inner plexiform cell layer, and ganglion cell layer. Immunoreaction within the photoreceptor cell layer was dependent on dark/light adaptation state of retinas. Immunoblot analysis of rod outer segments (ROS) with monoclonal or polyclonal antibodies to PLCγ1 showed the presence of an immunoreactive band of 140 kDa. ROS prepared from retinas light‐adapted in vitro had more PLCγ1 on immunoblots than ROS from dark‐adapted retinas. PLC enzyme activity in ROS from light‐adapted retinas was 69 and 46% higher than ROS from dark‐adapted retinas, when assayed in the presence and absence of ATP, respectively. This increase in enzyme activity was observed at [Ca2+]free between 0.32 and 100 µM. These results demonstrate the presence of PLCγ1 in bovine ROS and show that ROS prepared from light‐adapted retinas are enriched in this isozyme, suggesting that light may promote the binding of this isozyme to bleached ROS membranes.

Objectives The severity of acute carbon monoxide (CO) poisoning is often based on non-specific clinical criteria because there are no reliable laboratory markers. We hypothesized that a pattern of plasma protein values might objectively discern CO poisoning severity. This was a pilot study to evaluate protein profiles in plasma samples collected from patients at the time of initial hospital evaluation. The goal was to assess whether any values differed from age- and sex-matched controls using a commercially available plasma screening package. Methods Frozen samples from 63 suspected CO poisoning patients categorized based on clinical signs, symptoms, and blood carboxyhemoglobin level were analyzed along with 42 age- and sex-matched controls using Luminex-based technology to determine the concentration of 180 proteins. Results Significant differences from control values were found for 99 proteins in at least one of five CO poisoning groups. A complex pattern of elevations in acute phase reactants and proteins associated with inflammatory responses including chemokines/cytokines and interleukins, growth factors, hormones, and an array of auto-antibodies was found. Fourteen protein values were significantly different from control in all CO groups, including patients with nominal carboxyhemoglobin elevations and relatively brief intervals of exposure. Conclusions The data demonstrate the complexity of CO pathophysiology and support a view that exposure causes acute inflammatory events in humans. This pilot study has insufficient power to discern reliable differences among patients who develop neurological sequelae but future trials are warranted to determine whether plasma profiles predict mortality and morbidity risks of CO poisoning.