Comparison of in vitro proliferative capacity of human periodontal ligament cells in juvenile and aged donors

OBJECTIVE: The aim of this study is to compare the in vitro proliferative capacity of periodontal ligament (PDL) cells from aged and juvenile donors.
MATERIALS AND METHODS: Flow-cytometric analysis of the cell cycle was used to compare the length of each cell cycle, and the ratio of the cells progressing through the cycles between four PDL cells from juvenile donors and four cells from aged donors. Then, replicative capacity of the PDL cells from three juvenile and three aged donors was compared by serial cultureS. Finally, expression of c-fos was compared between cells proliferating and cells which had reached senescent.
RESULTS: Flow-cytometric analysis of the cell cycle had revealed that although there were no differences in the length of each phase of the cell cycle, significant differences were found in the ratio of the cells entering from Gap 1 to DNA synthesis phase of the cell cycle ( P < 0.025).Replicative capacity was much longer in two cells from juvenile donors (about 20 population doublings), while all cells from aged donors showed short dividing abilities (less than eight population doublings), hence entered senescent phases shortly. Additionally, no c-fos was detected in cells which had reached senescence upon stimulation with serum.
CONCLUSIONS: It is generally believed that aged humans have an impaired wound healing ability. We believe that more fibrotic PDL tissues seen in aged humans might be the reason for this, and suggest that this phenomena might be due to the progressive accumulation of senescent cell populations.     

DENTAL CARIES AND PERIODONTAL DISORDERS IN CHRONIC LIVER DISEASE

Bacterial infections are frequent complications in patients with chronic liver disease (CLD). A potential source of infection may be dental foci. This study was carried out to assess the association of CLD with dental caries and periodontal disease. Dental caries and periodontal examinations were performed prospectively in patients with CLD (group A) and controls without any liver disease (group B). Similar examination was also carried out in alcoholics without liver disease (group C) as well as in cases with portal hypertension but no liver disease (group D) i.e. patients with Non Cirrhotic Portal Fibrosis and Extrahepatic portal obstruction. A total of 231 subjects (Group A:83, group B: 75, group C:46 and group D:27) were studied. Group A included 32 cases with chronic hepatitis B&C, 26 with alcoholic cirrhosis, 14 with postnecrotic cirrhosis, and 11 with cryptogenic cirrhosis. Measures of oral hygiene (p < 0.01), dental care (p < 0.001), and periodontal parameters were worse and the number of teeth requiring treatment (p < 0.05) was higher in alcoholics with or without cirrhosis than in healthy subjects and nonalcoholic patients with cirrhosis. Alcoholics had a lower, total number of teeth than patients without alcohol abuse and healthy controls (p < 0.01). The dental caries and periodontal status of patients with nonalcoholic cirrhosis did not differ significantly from group B. The severity and duration of liver disease had no influence on dental caries and periodontal disease. The presence of chronic alcohol abuse rather than cirrhosis or portal hypertension is a major predisposing factor for dental caries and periodontal diseases. In alcoholics, these diseases appear to be caused primarily by bad oral hygiene and poor dental care.KEY WORDS: Alcohol abuse, Chronic liver disease, Dental caries, Periodontal disease     

Reduction in membrane component of diffusing capacity is associated with the extent of acute pulmonary embolism

Acute pulmonary embolism (PE) often decreases pulmonary diffusing capacity for carbon monoxide (DL,CO), but data on the mechanisms involved are inconsistent. We wanted to investigate whether reduction in diffusing capacity of alveolo-capillary membrane (DM) and pulmonary capillary blood volume (Vc) is associated with the extent of PE or the presence and severity of right ventricular dysfunction (RVD) induced by PE and how the possible changes are corrected after 7-month follow-up. Forty-seven patients with acute non-massive PE in spiral computed tomography (CT) were included. The extent of PE was assessed by scoring mass of embolism. DL,CO, Vc, DM and alveolar volume (VA) were measured by using a single breath method with carbon monoxide and oxygen both at the acute phase and 7 months later. RVD was evaluated with transthoracic echocardiography and electrocardiogram. Fifteen healthy subjects were included as controls. DL,CO, DL, CO/VA, DM, vital capacity (VC) and VA were significantly lower in the patients with acute PE than in healthy controls (P < 0.001). DM/Vc relation was significantly lower in patients with RVD than in healthy controls (P = 0.004). DM correlated inversely with central mass of embolism (r = -0.312; P = 0.047) whereas Vc did not. DM, DL,CO, VC and VA improved significantly within 7 months. In all patients (P = 0.001, P = 0.001) and persistent RVD (P = 0.020, P = 0.012), DM and DL,CO remained significantly lower than in healthy controls in the follow-up. DM was inversely related to central mass of embolism. Reduction in DM mainly explains the sustained decrease in DL,CO in PE after 7 months despite modern treatment of PE.