Harmful at non-cytotoxic concentrations: SiO2-SPIONs affect surfactant metabolism and lamellar body biogenesis in A549 human alveolar epithelial cells

The pulmonary delivery of nanoparticles (NPs) is a promising approach in nanomedicine. For the efficient and safe use of inhalable NPs, understanding of NP interference with lung surfactant metabolism is needed. Lung surfactant is predominantly a phospholipid substance, synthesized in alveolar type II cells (ATII), where it is packed in special organelles, lamellar bodies (LBs). In vitro and in vivo studies have reported NPs impact on surfactant homeostasis, but this phenomenon has not yet been sufficiently examined. We showed that in ATII-like A549 human lung cancer cells, silica-coated superparamagnetic iron oxide NPs (SiO₂-SPIONs), which have a high potential in medicine, caused an increased cellular amount of acid organelles and phospholipids. In SiO₂-SPION treated cells, we observed elevated cellular quantity of multivesicular bodies (MVBs), organelles involved in LB biogenesis. In spite of the results indicating increased surfactant production, the cellular quantity of LBs was surprisingly diminished and the majority of the remaining LBs were filled with SiO₂-SPIONs. Additionally, LBs were detected inside abundant autophagic vacuoles (AVs) and obviously destined for degradation. We also observed time- and dose-dependent changes in mRNA expression for proteins involved in lipid metabolism. Our results demonstrate that non-cytotoxic concentrations of SiO₂-SPIONs interfere with surfactant metabolism and LB biogenesis, leading to disturbed ability to reduce hypophase surface tension. To ensure the safe use of NPs for pulmonary delivery, we propose that potential NP interference with LB biogenesis is obligatorily taken into account.     

Reversal of granulocyte adherence to nylon fibers using local anesthetic agents: possible application to filtration leukapheresis

The effects of the cationic anesthetic agents tetracaine and lidocaine on granulocyte function, morphology, and adherence to nylon fibers were studied in an attempt to improve current methods of granulocyte collection by filtration leukapheresis (FL). When dissolved in acid- citrate-dextrose (ACD) plasma, these drugs significantly increased granulocyte elution from the fibers in a dose-related fashion. Granulocytes exposed to tetracaine and lidocaine remained more than 95% viable, retained normal bactericidal capacity after the drugs were washed from the cells, and had preserved membrane integrity, as evidenced by the normal ultrastructural appearance of tetracaine- exposed cells and an absence of leakage of lysozyme or lactic dehydrogenase. Granulocytes eluted with the anesthetic agents were rounded in shape with a reduction in the number of filopodial cytoplasmic projections and a relative absence of cytoplasmic vacuolization when compared to granulocytes eluted with ACD plasma alone. Dose-related inhibition of phagocytosis and adherence, which was largely reversible after washing the granulocytes, was noted. Greater than 95% of the lidocaine could be removed from the eluate with a single centrifugation and resuspension, indicating that granulocytes prepared by FL with anesthetic-enhanced elution could be potentially transfusable.     

Platelets inhibit the induction of nitric oxide synthesis by interleukin-1 beta in vascular smooth muscle cells

We have investigated the role of platelets in regulating the hemostatic and vasomotor properties of vascular smooth muscle. Experiments were performed to examine the effect of the releasate from activated platelets on the production of nitric oxide from interleukin-1 beta (IL- 1 beta)-treated cultured rat aortic smooth muscle cells. Treatment of vascular smooth muscle cells with IL-1 beta resulted in significant accumulation of nitrite in the culture media and in marked elevation of intracellular cyclic guanosine monophosphate (GMP) levels. The releasate from collagen-aggregated platelets blocked the IL-1 beta- mediated production of nitrite and the accumulation of cyclic GMP in smooth muscle cells in a platelet number-dependent manner. In functional assays, the perfusates from columns containing IL-1 beta- treated smooth muscle cells relaxed detector blood vessels without endothelium and the addition of IL-1 beta-treated smooth muscle cells to suspensions of platelets inhibited their thrombin-induced aggregation. The simultaneous treatment of smooth muscle cells with IL- 1 beta and the platelet releasate abolished both the vasorelaxing activities of the perfusates and the inhibition of platelet aggregation. Platelet releasates treated with a neutralizing antibody to platelet-derived growth factor (PDGF) failed to block IL-1 beta- induced nitric oxide production by the smooth muscle cells, as measured by both biochemical and functional assays. The platelet releasate from a patient with gray platelet syndrome likewise failed to block IL-1 beta-induced nitrite release by smooth muscle cells. These results demonstrate that platelets downregulate the production of nitric oxide by IL-1 beta-treated vascular smooth muscle cells through the release of PDGF. This effect may represent a novel mechanism by which platelets regulate vasomotor tone and thrombus formation at sites of vascular injury.     

Videothoracosopy in diagnosis and surgical treatment of tuberculosis

From 1993 to May 2001, 795 psychiatric patients were treated including 563 with pleural effusion, 98 with multiple or solitary tuberculoma, 69 with tuberculous empyema, 14 with fibrotic-cavitary tuberculosis, 51 with disseminated tuberculosis. Mean age of the patients was 32 years. Survey of pleural cavity with pleural or lung biopsy was performed in 691 patients. In tuberculoma 14 lobectomies were performed, 23 patients underwent atypical lung resection without stapler (including with precise technique). Bilateral on-stage interventions were made in 32 patients. In empyema necrectomy and lung decortication were performed. 14 patients underwent videocavernoscopy with sequestrectomy and cavity drainage. In disseminated tuberculosis lung biopsy without staplers was usually performed. Aerohemostasis was achieved with plasma stream. One patient with empyema and one patient with pleural effusion died (lethality was 0.25%). Rate of postoperative complications was 7.5% in tuberculoma and 1.5% in disseminated tuberculosis. Conversion to thoracotomy was necessary in 3 (3%) patients with tuberculoma and 12 (17%) patients with empyema. Mean hospital stay was 4 days after diagnostic surgery and 7 days after lung resection. In pleural effusion diagnosis was verified in 98% cases, in disseminated tuberculosis--in 100%. Videothoracoscopy is the best diagnostic method for pleural effusion and disseminated forms of lung tuberculosis and operation of choice in tuberculoma and empyema. Videothoracoscopy in tuberculosis is highly effective and associates with low rate of postoperative complications and lethality.     

Surgical treatment of stage IIIA non-small-cell lung cancer

Data on five-year survival were evaluated for 258 patients with non-small cell lung cancer (stage IIIA) (N2). In 155 patients (60%), N2 tumor was detected during surgery. Total resection was carried out in 179 (69.4%), subtotal--79 (30.6%). Total lymph node dissection was not employed in the latter group. Lateral thoracotomy was used in 213 cases. Transsternal procedure was performed in 45 cases of bulky tumor and extensive invasion of mediastinal fat. A comparison of five-year survival data failed to establish any relationship between survival and postoperative radiochemotherapy in radically-operated patients. It was found that surgery for non-small lung N2 tumors with mediastinal involvement is indicated and may be effective if total lymph node dissection is performed.     

Effect of an increase in the intracellular concentration of calcium ions on the transmembrane current induced by iontophoretic injection of cAMP into Helix pomatia neurons

The effect of intracellular Ca2+ concentration increase on transmembrane current induced by cAMP injection into a neuron (cAMP-current) was studied on Helix pomatia neurons under voltage clamp conditions. The elevation of intracellular Ca2+ concentration was produced by iontophoretic injection of Ca2+ into the cytoplasm, generation of action potentials, addition of uncouplers of oxidative phosphorylation into the external solution resulting in Ca2+ efflux from mitochondria. It was found that elevation of the intracellular Ca2+ concentration increases the amplitude of the cAMP-current and in most cases its duration as well. It is suggested that membrane structures responsible for the cAMP-current have two centers of phosphorylation: cAMP-dependent and Ca2+-calmodulin-dependent. Possible role of the studied process in integration of signals on the intraneuronal level is discussed.