Evaluation of airway inflammation by quantitative Th1/Th2 cytokine mRNA measurement in sputum of asthma patients.

BACKGROUND: Asthma is a chronic inflammatory disorder of the airways driven by T cell activation. Th2 cells and their cytokines are thought to play a role in the pathophysiology of allergic as well as non-allergic asthma. METHODS: Airway cells were obtained by sputum induction from 15 healthy and 39 asthmatic individuals and the airway T cell cytokine profiles (interleukin (IL)-4, IL-5, IL-13, IL-10 and interferon (IFN)-gamma) at the mRNA level were studied by real time RT-PCR. RESULTS: Asthma patients had increased expression of IL-5 (p = 0.001) and IL-13 (p = 0.03) mRNA in sputum compared with non-asthmatic controls. IL-4 mRNA and IFN-gamma mRNA were detectable in the sputum of 44% and 21% of patients, respectively, but not in controls. Sputum IL-10 mRNA levels did not differ significantly between patients and controls. Sputum mRNA expression levels of IL-4, IL-5, and IL-13 were significantly correlated with the percentage of eosinophils and were higher in subjects with allergic asthma than in those with non-allergic asthma (p = 0.03, p = 0.02 and p = 0.0002, respectively); they did not differ between mild asthmatic subjects and those with moderate to severe asthma. In contrast, IFN-gamma mRNA expression was higher in non-allergic than in allergic patients (p = 0.04) and higher in patients with moderate to severe asthma than in those with mild asthma (p<0.01). Sputum IL-5 mRNA levels (but not the other cytokine mRNA levels) were also correlated with exhaled nitric oxide (eNO) and with bronchial hyperreactivity expressed as the histamine concentration resulting in a 20% decrease in forced expiratory volume in 1 second. CONCLUSION: Real time RT-PCR analysis of mRNA in induced sputum confirms a predominance of Th2 cytokines in both allergic and non-allergic asthma. IL-5 levels reflect eosinophil infiltration as well as eNO levels and hyperreactivity, and levels of the Th1 cytokine IFN-gamma indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.

Stenosis development at the distal anastomosis of prosthetic bypasses for aortoiliac occlusive disease. Incidence and accuracy of colour flow duplex in the diagnosis.

When bypasses for aortoiliac occlusive disease fail they often do so because of a stenosis at the distal anastomosis. To assess the incidence of stenotic lesions and to establish the diagnostic reliability of colour-flow Duplex scanning, we investigated 103 aortoiliac and aortofemoral bypasses using intravenous (i.v.) digital subtraction angiography (DSA) as the reference method. Stenotic lesions at or just beyond the distal anastomosis were identified by i.v. DSA in 30 patients. The stenosis had a 30-49% diameter reduction (DR) in 10, 50-79% DR in 17 and 80-99% DR in three patients. The incidence of stenoses identified within the first 3 years following the operation was 33%, in the period of 3-6 years 20%, in the period of 6-9 years 32% and for bypasses longer than 9 years after the operation 50%. Colour-flow imaging had a 89% sensitivity in identifying the presence and location of distal anastomotic stenosis and a 95% specificity of ruling out significant lesions. A threshold value of 0.65 of the index between the peak systolic velocity (PSV) at a normal vascular segment and the maximum PSV at the side of stenosis demonstrated lesions with a sensitivity of 86% and a specificity of 90%. Prophylactic repair of a high grade stenosis (> 70% DR) was performed in only two patients. Colour-flow Duplex is accurate in identifying distal anastomotic stenoses. Although the precise incidence of these lesions can be determined only by a prospective surveillance study, available data suggests a low yield of cases requiring prophylactic repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of a color-flow duplex surveillance program on infrainguinal vein graft patency: a five-year experience.

PURPOSE AND METHODS: The contribution of color-flow duplex surveillance to improving vein graft patency was evaluated in two patient groups after 201 infrainguinal bypass procedures were performed during a 5-year period. Incidence of revision procedures and the primary and assisted primary patency rates were compared for 160 bypass grafts monitored during the first 2 years by use of color-flow duplex scanning of the vein graft and adjacent arterial segments (color-flow surveillance group) versus 41 bypass grafts monitored by use of clinical assessment alone (clinical follow-up group). Only grafts that were patent after the first postoperative month are considered. RESULTS: The two groups were comparable with regard to most of the pertinent clinical factors. Stenotic lesions were identified in 58 bypass grafts, and severity was determined by use of intraarterial digital subtraction angiography. Eighteen bypass grafts with stenoses did not undergo a revision for reasons that were determined by the doctor, the hospital, or the patient. The occlusion rates of revised and nonrevised stenotic grafts were compared for lesions of different severity. None of the grafts for stenoses with 30% to 49% diameter reduction (DR) failed during follow-up. Occlusion occurred in 57% of the nonrevised and 9% of revised grafts (p = 0.047) for stenoses with 50% to 69% DR. Stenoses with 70% or greater DR were associated with graft failure in 100% of nonrevised bypasses and in 10% of revised grafts (p = 0.004). The assisted primary patency rate was higher in grafts that underwent color-flow surveillance compared with grafts with that underwent clinical follow-up (3-year patency rates of 91% and 72%, respectively; p = 0.004). The independent correlation of color-flow surveillance with higher patency rates was demonstrated in a proportional hazard analysis. The relative risk (probability of occlusion) in color-flow surveillance grafts is less than one third of the relative risk in bypass grafts that underwent clinical follow-up. CONCLUSIONS: We conclude that revision procedures were more optimally used during color-flow surveillance, whereas asymptomatic stenotic graft lesions are missed with clinical follow-up, which results in a higher percentage of graft failures. Overall graft patency rates can be improved with use of color-flow duplex surveillance and repair of significant stenotic lesions.

Surveillance of lower extremity vein grafts.

Development of stenosis in lower extremity vein grafts or its anastomotic segments is responsible for most graft failures. While these lesions can be treated by minor procedures, timely identification may improve long-term graft patency. In this review, diagnostic methods that are currently applied for vein graft surveillance, criteria for stenosis and recommendations for intervention are discussed.