Uteri and cervices were obtained from estrous rabbits (controls) and from rabbits 24 h or 7 days after a single intramuscular injection of medroxyprogesterone acetate (MPA; 2.14 mg/kg). Estrogen and progesterone receptor concentrations were measured by Scatchard analysis, cell-free DNA synthesis was measured by (3H)-TTP incorporation, and tissue sections were examined histologically. The uterine endometrium underwent marked changes in histology, including extensive infoldings of the mucosal surface, glands were continuous into crypts and secretory epithelial cells were noted. In addition, total estrogen receptor content and DNA synthesis were decreased. In contrast, there was no significant change in the histology of the endocervical epithelial-stromal complex, and total estrogen receptor remained constant. However, DNA synthesis in the endocervix was decreased. Thus we conclude that: DNA synthesis is not linked to changes in estrogen receptor in the endocervix; and differential effects of progestogen on the estrogen receptor system occur coincident with different morphological responses within two target tissues from the same animal.

Animals↗

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The role of Bacteroides melaninogenicus and other anaerobes in periodontal infections.

Recent taxonomic and anatomical studies of dental plaque associated with periodontal health and disease have demonstrated that differences in the microbial populations in plaque may be responsible for the initiation and progression of disease. The consistent isolation of large numbers of anaerobic and capnophilic bacteria from the depths of periodontal lesions has suggested an important role for these organisms. Bacteria that have been isolated include Capnocytophaga (Bacteroides ochraceus), other species of Bacteroides, Fusobacterium, Selenomonas, spirochetes, Campylobacter, Veillonella, Actinomyces, Propionibacterium, Peptococcus, and other genera. The periodontopathic potential of oral strains of Bacteroides melaninogenicus has been explored in a number of investigations because these organisms are consistently isolated from periodontal lesions. Studies of B. melaninogenicus have included purification of a capsular substance, characterization of the lipopolysaccharide and a variety of toxic substances and lytic enzymes, and ecologic aspects of its colonization. Understanding of the nature and pathogenic mechanisms of the oral microbiota may lead to control of this pandemic infection.

Bacteroides Infections↗

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Anaerobic oral and dental infection.

Anaerobes make up a significant part of the oral and dental indigenous and pathogenic flora. Their role in periodontal disease, root canal infections, infections of the hard and soft oral tissue, as well as their importance as foci for disseminated infectious disease is well established. Despite the ubiquitous involvement of bacteria, significant progress in our understanding of specific microbial etiologies has occurred only in the past decade. Estimates of the number of species recovered from samples of subgingival plaque range from 250 to 400, a large portion made up by anaerobes. Common anaerobic isolates include Fusobacterium, Bacteroides, Actinomyces, Peptococcus, Peptostreptococcus, Selenomonas, Eubacterium, Propionibacterium, and Treponema. Recently, several significant advances in our knowledge have set the stage for future research. First, circulating levels of hormones in pregnant women were shown to be stimulatory to Bacteroides species, which were associated with increased levels of gingival infection. Second, bacterial invasion of the soft and hard periodontal tissues has been documented in gingivitis, advanced periodontitis, and localized juvenile periodontitis. The frequency and identity of invading bacteria will determine the implications for diagnosis and treatment. Third, antibacterial "probes" aimed at anaerobic (and capnophilic) bacteria have had promising results in controlling and arresting oral, dental, and peridontal anaerobic infections.

Anti-Bacterial Agents↗

PubMedDate not supplied