Isolated lung perfusion: single-pass system versus recirculating blood perfusion in pigs.

BACKGROUND: Cytostatic isolated lung perfusion has been advocated for treating pulmonary metastasis of soft tissue sarcoma. Different techniques of isolated lung perfusion have been developed. METHODS: Isolated lung perfusion with and without doxorubicin was performed on white pigs during 15 minutes either by a single-pass system (n = 7) or by a recirculating-blood perfusion system (n = 7). Three animals with endovenous drug application served as controls. Leakage was assessed using isotopic tracers. Perfusion-induced lung tissue injury was determined by postperfusion chest radiographs, by angiotensin-converting enzyme-to-protein ratio in the plasma and in the bronchioalveolar lavage fluid, and by wet-to-dry weight ratio and histologic examination of lung biopsy specimens at 20 and 50 minutes. Doxorubicin concentration in lung tissue and plasma was compared between the three study groups. RESULTS: All isolated lung perfusion studies were successfully performed without significant systemic leakage (< 0.6%). Wet-to-dry weight ratio was significantly lower after single-pass as compared with recirculating-blood perfusion and endovenous drug application at both time points (5.0 +/- 1.1 and 5.3 +/- 0.8 for single-pass versus 6.6 +/- 1.1 and 6.9 +/- 0.5 for recirculating-blood versus 6.6 +/- 0.2 and 5.9 +/- 0.7 for the control group, respectively; p < 0.05). Angiotensin-converting enzyme-to-protein plasma ratio in the single-pass group was significantly lower only at 20 minutes (6.3 +/- 2.4 versus 9.3 +/- 1.0 versus 9.7 +/- 1.9, respectively; p < 0.05) but not at 50 minutes. Angiotensin-converting enzyme-to-protein ratio in bronchoalveolar lavage fluid, histology of lung biopsy specimens, and chest radiographs did not differ significantly between the three groups. Doxorubicin lung tissue concentration was not significantly different after single-pass (17.5 micrograms/g) and recirculating-blood perfusion (21.9 micrograms/g), but was significantly higher than after endovenous drug application (3.0 micrograms/g; p < 0.01). CONCLUSIONS: Both isolated lung perfusion techniques resulted in a sixfold to sevenfold higher doxorubicin lung tissue concentration than after endovenous application. Isolated lung perfusion-induced lung injury was similar for both techniques, but recirculating-blood perfusion appeared to result in more acute lung injury and was technically more demanding than single-pass perfusion.

Cardioprotection in patients undergoing chemo- and/or radiotherapy for neoplastic disease. A pilot study.

OBJECTIVES: To assess the cardioprotective efficiency of an antioxidant regimen (vitamins E, C and N-acetylcysteine) in patients receiving high dose chemo- and/or radiotherapy for malignant disease. METHODS: Prospective, placebo controlled, randomized and double blinded pilot study involving 13 patients receiving chemotherapy and 12 patients receiving radiotherapy. RESULTS: In patients receiving antioxidants, left ventricular ejection fraction did not change (63 +/- 4% to 63 +/- 4%). In the placebo group, ejection fraction changed from 67 +/- 6% to 61 +/- 4% (p = 0.03). No patient in the antioxidant group and 6/13 (46%) patients in the placebo group showed a fall of > 10% in the left ventricular ejection fraction. In the chemotherapy group, the left ventricular ejection fraction changed from 62% (+/- 2) to 63% (+/- 2) in the patients treated with antioxidants (ns) and from 63% (+/- 5) to 61% (+/- 5) in patients treated with placebo (ns). No patient showed a significant fall in ejection fraction in the antioxidant group, whereas 2/7 (29%) in the placebo group showed a reduction > or = 10%. In the radiotherapy group, left ventricular ejection fraction did not change ¿64% (+/- 6) to 64% (+/- 5)¿ in patients treated with antioxidants (ns) and changed from 70% (+/- 8) to 60% (+/- 4) in patients treated with placebo (p = 0.008). No patient in the antioxidant group, but 4/6 (66%) patients in the placebo group showed a fall of > or = 10% in ejection fraction. CONCLUSION: The small number of patients in the study precludes a definitive statement. The preliminary results however suggest efficient cardioprotection by this nontoxic and inexpensive antioxidant combination, so larger studies are warranted for confirmation.

Inhaled nitric oxide for high-altitude pulmonary edema.

BACKGROUND: Pulmonary hypertension is a hallmark of high-altitude pulmonary edema and may contribute to its pathogenesis. When administered by inhalation, nitric oxide, an endothelium-derived relaxing factor, attenuates the pulmonary vasoconstriction produced by short-term hypoxia. METHODS: We studied the effects of inhaled nitric oxide on pulmonary-artery pressure and arterial oxygenation in 18 mountaineers prone to high-altitude pulmonary edema and 18 mountaineers resistant to this condition in a high altitude laboratory (altitude, 4559 m). We also obtained lung-perfusion scans before and during nitric oxide inhalation to gain further insight into the mechanism of action of nitric oxide. RESULTS: In the high-altitude laboratory, subjects prone to high-altitude pulmonary edema had more pronounced pulmonary hypertension and hypoxemia than subjects resistant to high-altitude pulmonary edema. Arterial oxygen saturation was inversely related to the severity of pulmonary hypertension (r=-0.50, P=0.002). In subjects prone to high-altitude pulmonary edema, the inhalation of nitric oxide (40 ppm for 15 minutes) produced a decrease in mean (+/-SD) systolic pulmonary-artery pressure that was three times larger than the decrease in subjects resistant to such edema (25.9+/-8.9 vs. 8.7+/-4.8 mm Hg, P<0.001). Inhaled nitric oxide improved arterial oxygenation in the 10 subjects who had radiographic evidence of pulmonary edema (arterial oxygen saturation increased from 67+/-10 to 73+/-12 percent, P=0.047), whereas it worsened oxygenation in subjects resistant to high-altitude pulmonary edema. The nitric oxide-induced improvement in arterial oxygenation in subjects with high-altitude pulmonary edema was accompanied by a shift in blood flow in the lung away from edematous segments and toward nonedematous segments. CONCLUSIONS: The inhalation of nitric oxide improves arterial oxygenation in high-altitude pulmonary edema, and this beneficial effect may be related to its favorable action on the distribution of blood flow in the lungs. A defect in nitric nitric oxide synthesis may contribute to high-altitude pulmonary edema.

Dual-isotope SPET 201Tl rest/99mTc-MIBI stress: one-day protocol for pre-operative myocardial imaging?

We compared the results of a rest 201TI/stress 99mTc-MIBI protocol, both by means of separate single isotope and simultaneous dual isotope acquisition, with a standard stress/rest 99mTc-MIBI 2-day protocol in 11 patients with low probability of CAD and 14 patients with chronic CAD. In patients with CAD 406 segments (sgs) were analysed. In the standard protocol 119 sgs were classified as pathological of which 50.4% were fixed and 49.6% reversible defects. With the MIBI-stress/TI-rest single 33% of 119 pathological sgs were fixed and 67% reversible defects. With the MIBI-stress/TI-rest dual only 20% were fixed and 80% reversible defects. The reversibility of 59 MIBI-stress/MIBI-rest reversible defects was quantified: MIBI-stress/MIBI-rest 35 +/- 16% MIBI-stress/TI-rest single 50 +/- 26% and MIBI-stress/TI-rest dual 48 +/- 22%. The results of 99mTc-MIBI rest and 201TI rest studies in patients with chronic CAD are not the same. Dual-isotope 1-day 201TI-rest/99mTc-MIBI-stress SPET data, acquired separately, may give fast and complete information on myocardial perfusion at stress and rest, respectively, and on myocardial viability.

[Radionuclide venography in occlusions of the inferior vena cava]. / Radionuklidová venografie pri uzáverech dolní duté zíly.

Based on 1234 examinations made by radionuclide venography the authors evaluated a group of 11 patients, where an occlusion of the vena cava was proved. In five instances ascension of thrombosis from the area of the pelvic veins was involved. in three instances compression by a tumour, twice the cause of occlusion was surgical ligature of the vena cava inferior. In one instance suppurative thrombosis developed as a result of spread of the infection from an intraabdominal abscess. Radionuclide venography provided evidence of a collateral circulation, as a rule a combination of several collateral routes was involved. Most frequently parietal collaterals in the abdominal aorta were present (9X), 4X paravertebral venous routes and only once anastomoses into the system of the azygos vein. In six patients anastomoses via the portal vein were found (cavoportal anastomoses). Based on their own experience, the authors evaluated the importance of radionuclide venography. Its advantage is the possible administration of the radiopharmaceutical preparation into the peripheral vein on the leg, the simple, safe procedure, the reproducibility and diagnostic yield during detection of high occlusions in the area of the vena cava inferior.

Use of radionuclides in the diagnosis of thromboembolism of venous origin: its potential and limitations. A review.

The review discusses the potential and limitations of radionuclide (RN) techniques of examination in diagnosing thromboembolic disease of venous origin. The advantages and drawbacks of perfusion pulmonary scintigraphy as the most commonly used method are weighed especially with a view to the diagnosis of pulmonary embolism (PE). The need for a combined examination including inhalation scintigraphy and chest X-ray is underlined. The criteria for interpreting results of RN techniques of examination in assessing the presence of PE are defined. Of the methods used in the diagnosis of venous thrombosis, the benefits and limitations of the fibrinogen uptake test (FUT) and radionuclide venography (RNV) are pointed out. When comparing RNV with X-ray phlebography, the authors found a low sensitivity in the crural area (54%) and, on the contrary, a 100% agreement in the areas of iliac veins and the vena cava inferior.

[Comparison of radionuclide venography with roentgen phlebography]. / Srovnání radionuklidové venografie s rtg-flebografií.

The authors evaluated a group of 78 patients where in addition to radionuclide venography (RNV) also X-ray phlebography was used (RTGF) within a time interval of not more than 72 hours. The results of 102 examinations were compared, 276 areas were correlated at six different sites. Agreement was recorded in 249 instances (90%), a false negative finding in 23 (8%) and a false positive finding in 4 (2%). Sensitivity was low in the area of the calf (55%), high in the femoral area, iliac area and in the area of the inferior vena cava (92-100%). The specificity was in all areas, incl. the calf, relatively high (94-100%). The investigation revealed the disadvantages of RNV--a low reliability in the area of the calf, the impossibility to detect small and parietal thrombi, the inability to assess the "activity and age" of the thrombus, the more difficult interpretation in insufficiency of venous perforators, and advantages of RNV--a great reliability at higher parts of the venous system and after administration of radiopharmaceutical preparations (RF) into peripheral veins, the possibility of simultaneous examination of pulmonary perfusion without further administration of RF, a low failure rate of intravenous administration of RF (less than 2%); RF do not irritate the venous endothelium and therefore thrombosis cannot develop; in case of paravenous escape of RF local inflammations do not develop, the radiation load is low, there is a small probability of allergic reactions, the method is non-invasive, it can be frequently repeated and used for the follow-up of treatment.

[General problems of selection and interpretation of diagnostic methods]. / Nekteré obecné problémy výberu a interpretace diagnostických metod.

The author draws attention to general principles which must be respected in the selection and interpretation of diagnostic methods. He discusses the importance of basic characteristics of the diagnostic test (reliability, accuracy, sensitivity, specificity, predictive value) and their application in the examination process. He explains the importance of ROC analysis in the selection of the optimal diagnostic method. He refers to the criteria which must be taken into account when introducing and evaluating a new examination method.

[Initial experience with autologous thrombocytes labeled with 111indium-oxine]. / První zkusenosti s autologními trombocyty znacenými 111indium-oxinem.

The authors elaborated their own modification of the separation and labelling of autologous thrombocytes by means of 111indium-oxine which can be implemented in Czechoslovak departments of nuclear medicine with standard equipment. A total of 123 separations and labellings were made and 85 administrations to patients. The effectiveness of labelling by the described method was 79.5 +/- 6.9%, the separation yield of thrombocytes with regard to complete blood 44.3 +/- 13.8%. The aggregating capacity of the labelled platelets assessed in vitro after ADP stimulation (adenosine diphosphate) was 39.5 +/- 10.1% difference in optic density of platelet rich and platelet poor plasma which is evidence of the preserved viability of thrombocytes. "Recovery" during the 120th minute after administration of normal suspensions was 62.2 +/- 17.9%, the survival time of labelled thrombocytes 8.2 +/- 0.74 days. In patients with idiopathic thrombocytopenic purpura the "recovery" was 49.4 +/- 18%, the survival period 2.9 +/- 1.8 days. In patients after transplantation of the kidney complicated by acute rejection there was an increased accumulation of labelled platelets in the area of the kidney (count rate index 2.32 +/- 0.45). In normally functioning transplanted kidneys the count rate index was 1.42 +/- 0.06. On their own material the authors demonstrate other possibilities of clinical application of scintigraphy by means of labelled autologous platelets (a method hitherto not described in the Ccezhoslovak literature) for the detection of intracardial and arterial thrombosis.

[CT in pulmonary embolism]. / CT bei Lungenembolie.

In 47 patients with clinically suspected pulmonary emboli CT and scintillation tests were performed. Our result is, that in case of defects in the a. pulmonalis filled with contrast medium and pronounced CT-signs of pulmonary infarction embolization is likely even for a negative or unclear outcome of the scintillation tests.