Comparison of pulmonary and pleural responses of rats and hamsters to inhaled refractory ceramic fibers

The present study was designed to determine whether pleural fiber burdens or subchronic pleural fibroproliferative and inflammatory changes can help explain the marked interspecies differences in pleural fibrosis and mesothelioma that are observed following long-term inhalation of RCF-1 ceramic fibers by rats and hamsters. Fischer 344 rats and Syrian golden hamsters were exposed to RCF-1 for 4 h per day, 5 days per week, for 12 consecutive weeks. Lung and pleural fiber burdens were characterized during and after exposure. For all time points, approximately 67% of fibers associated with lung tissues from both rats and hamsters were longer than 5 microns in length. In comparison, fibers longer than 5 microns recovered from the pleural compartment, following a 12-week exposure and 12 weeks of recovery, accounted for 13% (hamsters) and 4% (rats) of the distribution. In the 12 weeks after the cessation of exposure, the number of fibers longer than 5 microns in length remained constant in the hamster at approximately 150 fibers per cm2 pleura. This was 2 to 3 times the corresponding fiber surface density in the rat. Significant pulmonary and pleural inflammation was detected at all time points and for both species. DNA synthesis by pleural mesothelial cells was quantified by bromodeoxyuridine uptake following 3 days of labeling. Labeling indices were higher in hamsters than in rats, both for RCF-1-exposed and filtered air-control animals and was highest for the parietal surface of the pleura. Significantly greater collagen deposition was measured in the visceral pleura of hamsters 12 weeks post-exposure but was not significantly elevated in rats. These findings demonstrate that subchronic inhalation exposure to RCF-1 induces pleural inflammation, mesothelial-cell turnover, pleural fibrosis, and an accumulation of fibers with a length greater than 5 microns in the hamster. The accumulation of long fibers in the pleural space may contribute to the pathology observed in the hamster following chronic inhalation of RCF- 1, whereas the presence of short, thin fibers may play a role in the acute-phase biological response seen in both species.      

Oxidized low-density lipoproteins accumulate in rat lung after experimental lung edema induced by alpha- naphthylthiourea (ANTU)

Oxidation of the low-density lipoprotein (LDL) results in the production of modified LDLs. Oxidation of LDL cholesterol plays a role on the pathogenesis of endothelial dysfunction. This study was designed to investigate the possible participation of the oxidative modification of low density lipoprotein in the lung edema induced by alpha-naphthylthiourea (ANTU), which is a well-known noxious chemical agent on the lung endothelium. When ANTU injected intraperitoneally into rats (15 mg kg(-1)), it produced lung edema as indicated by an increase in lung weight/body weight (LW/BW) ratio and pleural effusion (PE) reaching a maximum within 4 h. A significant lung edema was observed 4 h after intraperitoneally injection of alpha-naphthylthiourea when compared with olive oil-injected control rats. On microscopic examination of alpha-naphthylthiourea-treated rats were shown to have severe lung injury, while no change was observed in olive oil-treated control rats. While there were no staining in control lungs, positive oxidized low-density lipoproteins immune-fluorescent staining were observed in lung edema group. Our study showed that oxidized low-density lipoprotein (oxLDL) accumulated in ANTU-induced lung damage. This is the first study in which accumulation of oxLDL molecules in the intact lung tissue were shown by fluorescent immune-staining method in experimental lung edema. The potential role of oxLDL in this pathology are still under investigation.     

Ursodeoxycholic Acid Ameliorates Experimental Ileitis Counteracting Intestinal Barrier Dysfunction and Oxidative Stress

The aim of this study was to evaluate the effect of ursodeoxycholic acid (UDCA) on intestinal permeability (IP) and reactive oxygen species (ROS) generation in indomethacin-induced enteropathy, a well-known experimental model of Crohn's disease. Seventy-eight male Wistar rats were randomly assigned to receive indomethacin, indomethacin + UDCA, or vehicles. Indomethacin induced a significant increase in the fraction of urinary excretion of 51Cr-EDTA following oral administration (7.9 +/- 1.3 vs 2.3 +/- 0.2%; P < 0.05) and lucigenin-amplified chemiluminescence in intestinal fragments ex vivo (10.1 +/- 1.9 vs 2.6 +/- 0.4 cpm x 10(3)/mg; P < 0.05) compared to controls. UDCA significantly reversed these effects (P < 0.05), without being incorporated in biliary bile acid composition (HPLC analysis). These findings support a local protective effect of UDCA in experimental ileitis by the modulation of intestinal barrier dysfunction and oxidative stress. In short, they provide insights into mechanisms of action of UDCA in intestinal inflammation and a new perspective on the treatment of Crohn's disease.     

Obesity and type 2 diabetes mellitus: a population-based study of adolescents

A cross-sectional, population-based study was conducted on 1,647 Turkish adolescents to determine the prevalence of obesity, impaired fasting glucose (IFG) and type 2 diabetes mellitus (DM2), and to determine whether the recent increase in DM2 prevalence in some countries is applicable to this population. Information was gathered through a questionnaire. All children were screened with physical examination and fasting plasma glucose. 10.7% of adolescents were overweight (BMI 85-95th percentile) and 3.6% were obese (BMI > or =95th percentile). Mean BMI was 20.25 +/- 3.31 kg/m2 with maximum BMI 35.88 kg/m2. No child was diagnosed with DM2; 1.96% had IFG (110-126 mg/dl). No significant relationship was found between IFG and obesity, socio-economic status (SES) or family history of DM. The risk of obesity was increased among children with family history of DM or obesity, and among those who had low physical activity and were of high SES level. This analysis represents the population-based data upon which future studies will be based.     

Role of routine investigations in children presenting with their first febrile convulsion

To assess the role of routine investigations in children presenting with their first febrile convulsion, the results of investigations carried out in 328 children over a 2-year period were reviewed. Lumber puncture was performed in 96% of cases and resulted in the detection of 4 cases of unsuspected meningitis, one of which was bacterial. 2 children had normal lumbar punctures on admission but developed meningococcal meningitis within 48 hours. Sugar, calcium, urea, and electrolyte estimations, and blood counts were commonly performed but were unhelpful. We suggest that lumbar puncture in those children presenting with their first febrile convulsion under the age of 18 months is the only useful routine investigation.     

Neutrophil hypersegmentation in children with iron deficiency anemia

Neutrophil hypersegmentation (NH) is usually associated with vitamin B12 or folic acid deficiency. NH is seen in iron deficiency anemia but there are very few case studies about this. Neutrophil hypersegmentation was evaluated in 94 children with iron deficiency anemia; 23 healthy children comprised the control group with similar ages. NH was found in 76/94 (81%) in the study group and 2/23 (9%) of the control group. The difference was statistically significant (p < .01).