[Assessment of an association between fatty acid structure of lipids in pulmonary surfactant and 137Cs content in the body of children, residents of radiation-contaminated areas]

An evaluation of correlation between fatty acid composition in pulmonary surfactant lipids and 137Cs content in the body of children, residents of radiation-contaminated areas revealed that a increased incorporation of 137Cs promotes a disruption of fatty acid balance towards an increase in the saturation of the surfactant lipid complex, a destruction of lecithin fraction of surfactant, a decrease in antioxidant properties of surfactant system, an activation of lipid peroxidation processes in the respiratory area of lung by lipoxygenase type, a disturbance of polyunsaturated fatty acid metabolism on the stage of bioregulators-eicosanoid formation.

Early retardation of 99mTc-DTPA radioaerosol transalveolar clearance in irradiated canine lung

The alteration of 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) transalveolar clearance in an initial phase of radiation lung injury was experimentally investigated.

METHODS

Fourteen dogs were irradiated to the hemithorax with a single dose of 20 Gy. A DTPA radioaerosol study was performed before irradiation and on day 12 after irradiation. On day 14, the DTPA study was repeated again, with seven animals undergoing the study after inhalation of an aerosolized synthetic surfactant. The penetration index (P.I.) and clearance half-time (T(1/2)) of DTPA were measured in each lung. To evaluate the changes in lung surfactant after irradiation, alveolar lipids were stained in the resected lungs (n = 14), and the amounts of alveolar surfactant phospholipid and protein were measured by a bronchoalveolar lavage study in another six irradiated dogs.

RESULTS

In all of the 14 irradiated animals, DTPA radioaerosol distributed uniformly throughout the lungs without significant changes in P.I. The T(1/2) values in irradiated lungs were significantly prolonged compared with the matched baseline values and those in nonirradiated lungs (P < 0.05 and 0.001, respectively). The aerosolized synthetic surfactant retarded the DTPA clearance both in the irradiated and in the nonirradiated lungs (P < 0.001) without significant changes in P.I. The histologic and bronchoalveolar lavage studies revealed an increase of alveolar surfactant materials in the irradiated lungs without substantial histologic changes in the alveolar structures.

CONCLUSION

DTPA transalveolar clearance was retarded soon after irradiation. Increased alveolar surfactant may be partly responsible for this retarded DTPA clearance because the aerosolized synthetic surfactant also prolonged the clearance in nonirradiated lungs. A DTPA clearance test is sensitive for the early detection of radiation lung injury and seems helpful for clarifying the association of epithelial integrity changes and lung surfactant in radiation lung injury.

[The correction of hypoxic damage to the pulmonary surfactant system of rats with extremely high-frequency electromagnetic fields]

54 white rats were studied physically, histochemically and morphometrically for the effect of EHF electromagnetic field on repair of the lung surfactant system. The damage was inflicted by acute hypoxia existing at the altitude of 9000 m above the sea level simulated in the chamber. For the period studied natural repair was unable to secure the return to normal structure and function of the surfactant system, whereas daily 20-minute exposures to millimetric waves on the chest stimulated repair on after-exposure day 1-5 and provided normalization of all the physical and morphometric parameters.

[The use of EHF therapy in the rehabilitation of patients with chronic bronchitis at a moderate altitude]

Patients treated in mid-altitude conditions for chronic bronchitis were exposed to EHF radiation. As shown by positive changes in external respiration, systemic and pulmonary hemodynamics, immune status, surface activity of lung surfactant, EHF therapy is effective in chronic bronchitis with ventilation disorders. The more severe these disorders were, the more marked the benefit was.

[Antioxidant effect of a Ural licorice product in acute impairment of pulmonary surfactant by total gamma irradiation]

Total single irradiation of rats at a dose of 2 Gy caused activation of lipid peroxidation in lung surfactant and blood serum within 7 days. Most pronounced alterations occurred in content of 2-thiobarbituric acid-positive substances and in activity of the antioxidant system enzymes. Administration of the preparation isolated from Liquorice uraliensis within 2 weeks before the irradiation and within 7 days after the treatment contributed to inhibition of the radiation-induced lipid peroxidation.

[The peroxidation of pulmonary surfactant lipids in the postradiation period]

In experiments with Wistar female rats it has been shown that an acute whole-body gamma irradiation with doses of 2 and 7 Gy initiates lipid peroxidation in pulmonary surfactant (Sf). Increase in the level of lipid peroxidation products in Sf (hydroperoxides and TBA-active products) was observed during 2 months. Decrease in enzymatic activity of superoxide dismutase and glutathione reductase was occurred in the first hours reaching the minimum on days 7-14 after irradiation period. In animals exposed to dose of 0.5 Gy the normalization of the indices under study was observed on 30th day. The findings demonstrate a destructive effect of lipid peroxidation on pulmonary Sf at the average and lethal exposure doses.

[The effect of the lateral hypothalamic area on the pulmonary surfactant system]

The level of lipids, lipase activity and lungs' blood capacity were studied on 62 rats. Dispersal cobalt was infused into the hypothalamic lateral area of rats with adrenalectomy or injected with droperidol, obsidan, reserpine. Their effect upon the hypothalamus involved a decrease in surfactant phospholipids and lung's blood capacity. Possible adrenergic mechanisms of affecting the lung surfactant system are discussed.

Changes in surfactant in bronchoalveolar lavage fluid after hemithorax irradiation in patients with mesothelioma

Experimental studies have shown that the surfactant system of the lung is affected shortly after irradiation. It is unclear, however, whether surfactant plays a role in the pathogenesis of radiation pneumonitis. In the present study surfactant components (saturated phosphatidylcholine, surfactant protein A, phosphatidylglycerol, and phosphatidylinositol) and other phospholipids of bronchoalveolar lavage fluid (BAL) were studied in four patients with pleural mesothelioma before and during hemithorax irradiation (70 Gy) as well as zero, 1, 2, 3, and 4 months following irradiation. The concentrations of these same components and of soluble proteins were also estimated in the epithelial lining fluid (ELF) using urea as a marker of dilution. After radiotherapy, the concentrations of the surfactant components in ELF decreased to 12 to 55% of the control values before radiation, whereas the concentration of sphingomyelin in ELF increased ninefold. There were small changes in the other phospholipids. The concentration of soluble protein in ELF increased sevenfold. The minimum surface activity of crude BAL increased from 12 +/- 4 to 32 +/- 6 mN/m, and that of the sediment fraction of BAL increased from 7 +/- 4 to 22 +/- 6 mN/m, p less than 0.001. The protein-rich supernatant fraction of BAL from irradiated lung had a inhibitory effect on normal surfactant. There were significant correlations between the increasing severity of the radiologic changes on the one hand and, on the other, the saturated phosphatidylcholine/sphingomyelin ratio (p less than 0.001), the concentrations of soluble protein (p less than 0.001), and the concentrations of the surfactant components (p less than 0.02-0.001) in ELF.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of Chinese herb medicine in experimental radiotherapy

Extracts from a group of destagnative herbs, 764-1, and the effective chemical, 764-3, were tested by an in vitro experiment using a HeLa-S3 cell line. Under aerobic conditions, the shoulder of the cell survival curve diminished or disappeared according to the different doses of 764-1 used, but no change in slope was observed. In nitrogen, when the dose of 764-1 increased to 20 mg/ml (ID20), besides the disappearance of the shoulder, the slope of the curve also showed changes at lower doses (4-8 Gy); up to 10-25 Gy the curve became more flattened. 764-3 showed almost a similar effect by mainly affecting the shoulder of the survival curve. At low drug doses a SER as high as 1.87 might be obtained under hypoxic condition. At the same time 764-1 was used in testing the effect on radiation lung damage. It was found that 764-1 could markedly inhibit the change of alveolar surfactant at 1 and 3 weeks after radiation. A wide field of investigation is thus spread out in front of us on radiosensitization and protection. Further studies on 764-3 are carried out.

Contrast effects in photoelectron microscopy; UV dose-dependent quantum yields of biological surface components

The relative brightness of photoelectron microscopy images as a function of exposure to UV light has been determined from model systems representative of biological cell surface components. Quantitative data for amino acid homopolymers, yields. The photoelectron quantum yields, increase substantially over the initial values. For example, the quantum yields fo poly-L-tyrosine at 200 nm is initially about 5 X 10(-8) electron/incident photon. The quantum yield increases with 254 nm irradiation, leveling off at about 5 X 10(-4) electrons/incident photon after a dose of 3 X 10(21) quanta cm-2. Pre-irradiation of poly-L-tyrosine in the presence of certain chemical agents, for example, the Lewis base diborane (B2H6), results in a substantial reduction of the dose-dependent increase in quantum yield. Exposure to the reducing agent stannane (SnH4) essentially eliminates the effect. These chemical treatments provide methods of controlling the UV dose-dependent effects in the photoelectron images.

Early physiologic and biochemical effects of thoracic X-irradiation on the pulmonary surfactant system

A study of surfactant physiology and biochemistry was undertaken in mice who received varying doses of X-irradiation to the thorax. During the first 12 weeks after X-irradiation, the period which precedes radiation pneumonitis, there is an increase in the amount of DPC in both the lung and the alveolar surface lining layer. This increase begins about 7 days after irradiation, returns to control levels by 12 weeks, and coincides with a fall in the total number of AM's. Over-all synthesis of DPC in the lung and its transport to the alveolar surface, as determined by incorporation of 3H from glycerol and 14C from palmitate into PC in vivo, remained unchanged from control levels. These results may be explained in part by proliferation of type 2 pneumocytes following X-irradiation and by decreased removal of surfactant from the alveolar surface, possibly as a result of the depletion of the AM population. No changes in mechanical properties of the lung or in situ E tis or E surf occurred at this stage, nor were changes detected in the surface properties of the alveolar lavage fluid.

[Experimental study of the effect of cobalt irradiation on the rabbit lung]

Rabbit lungs were irradiated with a unique dose of 3,150 rads of CO60. The time related study (from the end of irradiation to 28 days after-wards) of the ultrastructural changes in the alveolo-capillary membrane, shows that the early lesions involve first of all the endothelium, then the epithelium and the surfactant, interstitial involvement being the latest. The course of the lesions is maximal on the 7th day, while interstitial involvement appears and is amplified in the three following weeks, whereas cellular involvement completely regresses. Qualitative study of phospholipids from the pulmonary washing fluid of the irradiated lung shows early changes in the composition of surfactant (fall in lecithins and appearance of substances with similar structure) then a return to a practically normal composition around the 21st day. The nature of this early change in surfactant is debated: is it a change in surfactant secreted and/or an early change in the process of synthesis of surfactant?