Background: Previous uncontrolled reports have suggested that HIV-seropositive persons develop an accelerated form of emphysema. Objective: To characterize the risk for emphysema in a stable outpatient population. Design: Controlled, cross-sectional analysis. Setting: Midwestern urban community. Participants: (n = 114) without AIDS-related pulmonary complications and HIV-seronegative controls 44), matched age smoking history. Measurements: Measurement function, bronchoalveolar lavage,...

Skeletal muscles are exposed to increased temperatures during intense exercise, particularly in high environmental temperatures. We hypothesized that heat may directly stimulate the reactive oxygen species (ROS) formation diaphragm (one kind of skeletal muscle) and thus potentially play a role contractile metabolic activity. Laser scan confocal microscopy was used study conversion hydroethidine (a probe for intracellular ROS) ethidium (ET) mouse diaphragm. During 30-min period, (42 degrees...

Lung volumes and inspiratory muscle (IM) function tests were measured in 16 competitive female swimmers (age 19 +/- 1 yr) before after 12 wk of swim training. Eight underwent additional IM training; the remaining eight controls. Vital capacity (VC) increased 0.25 liters (P less than 0.01), functional residual (FRC) 0.39 0.29 0.001), total lung (TLC) 0.35 0.47 0.025) swimmers, irrespective Residual volume (RV) did not change. Maximum mouth pressure (PImax) at FRC changed -43 18 cmH2O 0.005)...

Superoxide anion radical (O(2)(*-)) is released from skeletal muscle at rest and particularly elevated during conditions of heat stress (42 degrees C). Previous studies have shown that in isolated rat diaphragm O(2)(*-) release not dependent on mitochondrial electron transport, reduced NADP oxidase activity, or the integrity membrane channels. This study hypothesized release, as measured by cytochrome c reduction, linked to metabolism arachidonic acid. Phospholipase A(2) inhibition with...

▪ Objective: To describe a possible association between prolonged infection with human immunodeficiency virus (HIV) and pathophysiologic process suggestive of pulmonary emphysema. Design: Case series. Setting: The Ohio State University Hospital, Columbus, Ohio. Measurements Main Results: We four HIV-seropositive individuals ranging in age from 32 to 55 years who presented dyspnea. Radiographic examination the chest showed no infiltrates. All patients were presumed have had HIV (mean CD4...

Skeletal muscles produce and contribute to circulating levels of IL-6 during exercise. However, when core temperature is reduced, the response attenuated. Therefore, we hypothesized that hyperthermia may be an important independent stimulus for muscle IL-6. In cultured C2C12 myotubes, (42°C) increased gene expression 14-fold after 1 h 35-fold 5 37°C recovery; whereas exposure 41°C resulted in a 2.6-fold elevation at h. protein was secreted significantly elevated cell supernatant. Similar but...

Heat stroke (HS) induces a rapid elevation in number of circulating cytokines. This is often attributed to the stimulatory effects endotoxin, released from damaged intestine, on immune cells. However, parenchymal cells also produce cytokines, and skeletal muscle, comprising large proportion body mass, thought participate. We tested hypothesis that muscle exhibits cytokine response HS parallels systemic conscious mice heated core temperature 42.4°C (TcMax). Diaphragm hindlimb muscles showed...

In hypoxia, mitochondrial respiration is decreased, thereby leading to a buildup of reducing equivalents that cannot be transferred O 2 at the cytochrome oxidase. This condition, called reductive stress, can paradoxically lead enhanced formation reactive species, or decrease in ability cell defend against an oxidative stress. We hypothesized antioxidants would protect tissues under conditions hypoxia. Rat diaphragm strips were incubated tissue baths containing one four antioxidants:...

Many tissues produce reactive oxygen species (ROS) during reoxygenation after hypoxia or ischemia; however, whether ROS are formed is controversial. We tested the hypothesis that generated in skeletal muscle exposure to acute before reoxygenation. Isolated rat diaphragm strips were loaded with dihydrofluorescein-DA (Hfluor-DA), a probe oxidized fluorescein (Fluor) by intracellular ROS. Changes fluorescence due Fluor, NADH, and FAD measured using tissue fluorometer. The system had detection...

Skeletal muscles produce transient reactive oxygen species (ROS) in response to intense stimulation, disuse atrophy, heat stress, hypoxia, osmotic stretch and cell receptor activation. The physiological significance is not well understood. Protein phosphatases (PPases) are known be highly sensitive oxidants could contribute many different signalling responses muscle. We tested whether broad categories of PPases inhibited by levels acute oxidant exposure that do result loss contractile...

Loss of the intestinal barrier is critical to clinical course heat illness, but underlying mechanisms are still poorly understood. We tested hypothesis that conditions characteristic mild heatstroke in mice associated with injury epithelial lining tract and comprise a component dysfunction. Anesthetized were gavaged 4 kDa FITC-dextran (FD-4) exposed increasing core temperatures, briefly reaching 42.4°C, followed by 30 min recovery. Arterial samples collected measure FD-4 concentration plasma...

In heat stroke, cytokines are believed to play important roles in multiorgan dysfunction and recovery of damaged tissue. The time course the cytokine response is well defined passive stroke (PHS), but little known about exertional (EHS). this study we used a recently developed mouse EHS model measure responses circulating cytokines/chemokines gene expression muscle. A very rapid increase IL-6 was observed at maximum core temperature (Tc,max) that peaked 0.5 h disappeared by 3 h. IL-10 not...

It is likely that the pathophysiology of exertional heat stroke (EHS) differs from passive (PHS), but this has been difficult to verify experimentally. C57Bl/6 mice were instrumented with temperature transponders and underwent 3 wk training using voluntary forced running wheels. An EHS group was exposed environmental temperatures (Tenv) 37.5, 38.5, or 39.5°C at either 30, 50, 90% relative humidities (RH) while exercising on a wheel. Results compared sham-matched exercise controls (EXC) naïve...

Heat stroke afflicts thousands of humans each year, worldwide. The immune system responds to hyperthermia exposure resulting in heat by producing an array immunological proteins, such as interleukin-6 (IL-6). However, the physiological functions IL-6 and other cytokines are poorly understood. We hypothesized that plays a protective role conditions stroke. To test this, we gave small supplements mice prior exposing them hot environments sufficient induce Pretreatment with resulted improved...

There is increasing evidence that oxygen-derived free radicals produced during strenuous work by the diaphragm may contribute to fatigue and/or injury. However, precise identity of these oxygen remains unknown, inasmuch as are extremely short lived and their detection in biologic systems quite difficult. recent salicylate-trapping method be a useful means monitoring tissue production hydroxyl radical (.OH). This predicated on fact salicylate's phenolic ring can attacked .OH at 3 or 5...