Intravenous Pluronic F-127 in early burn wound treatment in rats.

A dramatic improvement in full skin thickness burn wounds in rats treated intravenously with the non-ionic surfactant Pluronic F-127 (F-127) has been demonstrated. In this study the F-127 was given 30 min postburn to simulate conditions encountered in a clinical setting. Anaesthetized male rats (300-320 g) received full skin thickness burns by immersion of the anterior chest wall (8 per cent body surface area in a 70 degrees C water-bath for 12 s). Burn wound area was measured immediately and after 48 h. Thirty minutes after the burn, half the animals received equal volumes (8 ml/kg body wt) of either saline or F-127 (12 mM/l concentration) via the tail vein. The animals autopsied at 48 h showed a significant (P < 0.05) reduction in the degree of wound contraction and the wound appeared grossly less damaged in the F-127-treated animals. Histologically, skin biopsies showed less of the microscopic damage usually associated with full skin thickness burns in the F-127-treated animals than in the saline controls. We also used thermography to measure skin temperature of the burn area at 90 min and 48 h postinjury demonstrating alterations in the F-127-treated animals (P < 0.05). In animals followed for 30 days postinjury, there was a significant (P < 0.01) improvement in the wound closure rates in the F-127-treated animals. These observations show a positive therapeutic effect of F-127 on the inflammatory process in the area of a burn that may improve wound healing.

Limitations of the exercise stress test in the detection of coronary artery disease in apparently healthy men.

During a 1-year period, the United States Air Force School of Aerospace Medicine reviewed routine exercise tests by 771 completely asymptomatic male flying personnel aged 35-54 years, who underwent the stress test as the sole screening procedure to detect latent coronary artery disease. All of the aviators had a normal baseline 12-lead electrocardiogram, which would not have required a stress test in accordance with current policies of the USAF Central Electrocardiographic Library. Of these 771 exercise tests, 153 were maximal treadmill tests without a previous Double Master's Step test, and 618 were Double Master's tests. Borderline abnormal or abnormal Double Master's tests were followed by treadmill testing. Airmen with abnormal treadmill tests were offered coronary angiography for clarification of the aeromedical significance of the test result. The predictive value of a routine abnormal treadmill test in a population of aircrew members with a borderline abnormal or abnormal Double Master's test ranged from 17-55%. Thus, mass screening for coronary artery disease with exercise stress tests in apparently asymptomatic individuals is hampered by a low yield of true positive test in an unacceptably high proportion of false positive results.

Correlation of subclinical candidal colonization of the dorsal tongue surface with the Walter Reed staging scheme for patients infected with HIV-1.

The correlation between subclinical candidal colonization of the dorsal tongue surface and the Walter Reed staging scheme for patients positive for human immunodeficiency virus (HIV-1) antibody is reported. Of 76 cytologic smears of the dorsal tongue surface, 12 (16.2%) demonstrated subclinical colonization. The mean peripheral helper T-lymphocyte count for patients with subclinical colonization was 304 +/- 226 cells/mm3 and was not significantly different from seropositive patients without colonization (411 +/- 209 cells/mm3). The Walter Reed scheme for assessing progressive immunodysregulation did not significantly correlate with the presence of subclinical colonization. This study suggests a more complex pathogenesis for oral candidiasis in HIV-1-infected patients rather than a direct link to peripheral helper T-lymphocyte depletion below a count of 400 cells/mm3.

Bisphosphonate-ciprofloxacin bound to Skelite is a prototype for enhancing experimental local antibiotic delivery to injured bone.

BACKGROUND: The risk of osteomyelitis after open bone fracture may be reduced by locally applied antibiotics. ENC-41-HP (E41), which comprises ciprofloxacin linked to a 'bone seeking' bisphosphonate, loaded on to carrier Skelite calcium phosphate granules (E41-Skelite) has favourable in vitro characteristics for application to wounded bone. This study assessed E41-Skelite in a rat model of acute tibial osteomyelitis. METHODS: Mechanically induced tibial troughs were contaminated with approximately log10 4 colony forming units (c.f.u.) of Staphylococcus aureus (Cowan 1 strain) 'resistant' to E41 (minimum inhibitory concentration 8-16 microg/ml), lavaged and packed with Skelite alone, or with E41-Skelite slurry. Animals were killed at 24 h (n = 62), 72 h (n = 46) or 14 days (n = 12), and each tibia was assessed for S. aureus load (c.f.u./g tibia) and histological appearance (14 days only). RESULTS: At 24 and 72 h, the tibias of rats treated with E41-Skelite (n = 54) had a significantly lower mean (s.e.m.) load of S. aureus than animals that received Skelite alone (n = 54): log10 3.6(0.2) versus 6.4(0.1) c.f.u./g respectively at 24 h (P < 0.001, Mann-Whitney rank sum test) and log10 4.4(0.2) versus 6.6(0.1) c.f.u./g at 72 h (P < 0.001). At 14 days, E41-Skelite-treated tibias had fewer bacteria, no signs of osteomyelitis and histological signs of healing. CONCLUSION: E41-Skelite, a prototype granulated topical antibiotic delivery system, reduced the development of infection in experimental bone wounds.

Binding of a Staphylococcus aureus bone pathogen to type I collagen.

We contrasted the collagen-binding potential of the experimental osteomyelitis pathogen, Staphylococcus aureus strain SMH, to several other strains. These included Cowan 1 (binder), Wood 46 (non-binder) and six capsular variants. These measurements were made using an 125I-collagen binding assay. Formalin-killed S. aureus SMH strongly bound commercial type I iodinated collagen (dissociation constant, Kd = 2 x 10(-9) M). The extent of binding was similar to Cowan 1. Binding was saturable and not inhibited by 100 mM solutions of D-glucose, D-galactose, D-mannose, methyl-alpha-L-fucopyranoside, L-hydroxyproline or L-glycine. D-lactose gave moderate inhibition of binding to collagen, and L-fucose was strongly inhibitory. Trypsinized SMH did not bind collagen. None of four Ruthenium-red-staining staphylococci (encapsulated) avidly bound type I collagen. The encapsulated Smith strain, for example, did not bind to collagen but its capsule-negative variant, Smith compact, showed extensive binding. Three of five non-encapsulated S. aureus were strong collagen binders. These data suggest that the prototype bone pathogen binds to the major protein component of bone's extracellular matrix. Collagen-binding is promoted by protein adhesin(s), not capsule. The latter, in fact, appeared to interfere with this interaction. Binding was inhibited by solutions containing the simple monosaccharide, L-fucose.