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     

fMRI response in the medial prefrontal cortex predicts cocaine but not sucrose self-administration history

Repeated cocaine exposure induces long-lasting neuroadaptations that alter subsequent responsiveness to the drug. However, systems-level investigation of these neuroplastic consequences is limited. We employed a rodent model of drug addiction to investigate neuroadaptations associated with prolonged forced abstinence after long-term cocaine self-administration (SA). Since natural rewards also activate the mesolimbic reward system in a partially overlapping fashion as cocaine, our design also included a sucrose SA group. Rats were trained to self-administer cocaine or sucrose using a fixed-ratio one, long-access schedule (6 h/day for 20 days). A third group of na?ve, sedentary rats served as a negative control. After 30 days of abstinence, the reactivity of the reward system was assessed with functional magnetic resonance imaging (fMRI) following an intravenous cocaine injection challenge. A strong positive fMRI response, as measured by fractional cerebral blood volume changes relative to baseline (CBV%), was seen in the sedentary control group in such cortico-limbic regions as medial prefrontal cortex and anterior cingulate cortex. In contrast, both the cocaine and sucrose SA groups demonstrated a very similar initial negative fMRI response followed by an attenuated positive response. The magnitude of the mPFC response was significantly correlated with the total amount of reinforcer intake during the training sessions for the cocaine SA but not for the sucrose SA group. Given that the two SA groups had identical histories of operant training and handling, this region-specific group difference revealed by regression analysis may reflect the development of neuroadaptive mechanisms specifically related to the emergence of addiction-like behavior that occurs only in cocaine SA animals.     

Microcephaly, lissencephaly, Hirschsprung disease and tetralogy of Fallot: a new syndrome?

We report an 8-month-old girl with extreme microcephaly, lissencephaly, tetralogy of Fallot and Hirschsprung disease. She has a history of infantile spasms with developmental stagnation. Various diagnoses were considered but none seem to fit her clinical presentation. This combination of findings has not been described in the past and we suggest that this may be a previously undescribed neurodevelopmental syndrome resulting from a global failure of neuronal migration.     

Role of C-terminal cysteine residues of Aspergillus fumigatus allergen Asp f 4 in immunoglobulin E binding

Among the several allergens cloned and expressed from Aspergillus fumigatus, Asp f 4 is a major one associated with allergic bronchopulmonary aspergillosis (ABPA). The structure-function relationship of allergens is important in understanding the immunopathogenesis, diagnosis, and treatment of allergic diseases. These include the epitopes, conformational or linear, deletion of the N or C terminus or both N and C termini, and glycosylation or nonglycosylation, all of which affect immune responses. Similarly, the role of cysteine residues present in allergens may yield useful information regarding the conformational structure of allergens and the immunoglobulin E (IgE) epitope interaction. Such information may help in developing new strategies towards immunotherapy. In order to define the role of cysteine in the interaction of the antibody with Asp f 4, we have constructed mutants by selectively deleting cysteine residues from the C-terminal region of the Asp f 4. Immunological evaluation of these engineered recombinant constructs was conducted by using sera from patients with ABPA, Aspergillus skin test-positive asthmatics, and healthy controls. The results demonstrate strong IgE binding with Asp f 4 and two truncated mutants, Asp f 4(1-234) (amino acids [aa] 1 to 234) and Asp f 4(1-241) (aa 1 to 241), while another mutant, Asp f 4(1-196) (aa 1 to 196), showed reactivity with fewer patients. The result suggests that deletion of cysteines and the alteration of IgE epitopes at the C-terminal end resulted in conformational changes, which may have a potential role in the immunomodulation of the disease.     

Fungi and allergic lower respiratory tract diseases

Asthma is a common disorder that in 2009 afflicted 8.2% of adults and children, 24.6 million persons, in the United States. In patients with moderate and severe persistent asthma, there is significantly increased morbidity, use of health care support, and health care costs. Epidemiologic studies in the United States and Europe have associated mold sensitivity, particularly to Alternaria alternata and Cladosporium herbarum, with the development, persistence, and severity of asthma. In addition, sensitivity to Aspergillus fumigatus has been associated with severe persistent asthma in adults. Allergic bronchopulmonary aspergillosis (ABPA) is caused by A fumigatus and is characterized by exacerbations of asthma, recurrent transient chest radiographic infiltrates, coughing up thick mucus plugs, peripheral and pulmonary eosinophilia, and increased total serum IgE and fungus-specific IgE levels, especially during exacerbation. The airways appear to be chronically or intermittently colonized by A fumigatus in patients with ABPA. ABPA is the most common form of allergic bronchopulmonary mycosis (ABPM); other fungi, including Candida, Penicillium, and Curvularia species, are implicated. The characteristics of ABPM include severe asthma, eosinophilia, markedly increased total IgE and specific IgE levels, bronchiectasis, and mold colonization of the airways. The term severe asthma associated with fungal sensitization (SAFS) has been coined to illustrate the high rate of fungal sensitivity in patients with persistent severe asthma and improvement with antifungal treatment. The immunopathology of ABPA, ABPM, and SAFS is incompletely understood. Genetic risks identified in patients with ABPA include HLA association and certain T(H)2-prominent and cystic fibrosis variants, but these have not been studied in patients with ABPM and SAFS. Oral corticosteroid and antifungal therapies appear to be partially successful in patients with ABPA. However, the role of antifungal and immunomodulating therapies in patients with ABPA, ABPM, and SAFS requires additional larger studies.