In vitro cytotoxicity and morphological assessment of smoke from polymer combustion in human lung derived cells (A549).

The application of polymer and composites in building and modern transport interiors raises concerns of potential health hazards during combustion. Cytotoxicity and morphological assessment of smoke from polymer combustion in human lung derived cells (A549) has been investigated. A laboratory scale vertical tube furnace was used for the generation of combustion products. A range of materials used in the building and transport industry including high density-polyethylene (HDPE), polypropylene (PP), polycarbonate (PC), and polyvinyl chloride (PVC), fiberglass reinforced polymers (FRPs), and melamine faced plywood (MFP) were studied. The exposure of combustion toxicants to human lung cells (A549) at the air/liquid interface was acquired using a Harvard Navicyte Chamber. Cytotoxic effects on human cells were assessed based on cell viability using a selected in vitro cytotoxicity assays, including NRU (neutral red uptake) and ATP (adenosine triphosphate). Morphological assessment on the effects of combustion products in human lung cells from selected materials including PVC, FRP and MFP was assessed using scanning electron microscopy (SEM). The volatile organic compounds from thermal decomposition products were identified using ATD-GCMS (Automatic Thermal Desorption Gas Chromatography Mass Spectrometry). NOAEC (No Observable Adverse Effect Concentration), IC(10) (10% inhibitory concentration), IC(50) (50% inhibitory concentration), and TLC (Total Lethal Concentration) values (mg/l) were generated. The following toxicity ranking was observed from the most toxic material to the least toxic using the NRU assay: PVC>PP>HDPE>PC >FRP-10>MFP>FRP-16; and the ATP assay: PVC>HDPE>PP>FRP-10>FRP-16>MFP>PC. The method described here could potentially be an alternative to current fire toxicity standards.

Gastroduodenal mucosa in peptic ulcer: endoscopic and histological assessment.

This study aimed to assess the prevalence of endoscopic and histological gastroduodenitis as well as helicobacter-like organisms in patients with peptic ulcer. After diagnostic endoscopy, gastroduodenal biopsy specimens were taken from thirty patients (n = 30) with clinical and endoscopic diagnosis of peptic ulcer (duodenal ulcer = 25, gastric ulcer = 5). Endoscopic gastroduodenitis occurred in 18 patients (60%). Histological gastritis was detected in the gastric body or antrum in 25 (83%) and duodenitis in 17 (57%) patients. There was significant correlation between endoscopic and histological gastritis (p < 0.05). Helicobacter-like organisms occurred in 73% of the patients with peptic ulcer and in 88% of the antral biopsy specimens showing antral gastritis. Presence of helicobacter-like organisms was in particular associated with acute on chronic gastritis compared to chronic gastritis (p < 0.01). Moreover the patients with gastritis were found to belong to the older age group and 81.8% had blood group O +ve (p < 0.01 and p < 0.05 respectively). We conclude that presence of helicobacter-like organisms in patients with peptic ulcer is significantly associated with acute on chronic gastritis.