The effect of indomethacin on alveolar bone loss in experimental periodontitis

This study was undertaken to determine if prostaglandins play a role in the events leading to loss of bone in the ligature model of periodontitis. Periodontitis was induced by placement of the ligatures around mandibular teeth on one side of the jaw of squirrel monkeys ( Saimiri sciureus ). From one day prior to ligature placement, half the animals were administered indomethacin (5 mg/kg/day), a potent inhibitor of prostaglandin synthesis. Animals were sacrificed after one and two weeks of experimental periodontitis. It was found that indomethacin treatment abolished the significant losses of alveolar bone height and bone mass seen in non-indomethacin-treated (NIT) animals following ligature placement. Indomethacin also depressed the large increase in osteoclast density measured at one week in the NIT animals. The results support the hypothesis that prostaglandins are an important mediator of bone loss in the ligature model of periodontitis. Evidence is also presented for the coupling of bone resorption with osteoblastic neo-osteogenesis on both periodontal ligament and endosteal bone surfaces.     

Clinical evaluation of a novel dental whitening lamp and light-catalyzed peroxide gel

OBJECTIVE: This study examined whether an ultraviolet light enhanced the whitening efficacy of a peroxide gel containing a photo-Fenton activator. METHODOLOGY: Fifty subjects were enrolled into the trial at two geographically separate sites. As directed by the randomization keys, teeth of half of the study subjects were concurrently exposed to the whitening lamp, while the gel was on their teeth, for a total light exposure of 45 minutes. The other half of the subjects received no light treatment. At each examination, clinical data were collected on the gingival index, shade score, and self-assessed dentinal hypersensitivity. RESULTS: Changes in tooth shade were significantly better (approximately 26% improvement; p < 0.05) for subjects exposed to the gel and dental whitening lamp (average = 7.7 shade changes) compared to subjects exposed to the gel only (average 6.1 shades) immediately after treatment. No reports of erythema, desquamation, ulceration of soft tissues, gross changes in teeth, gingiva, or restorations were documented. The relative changes in mean sensitivity scores were similar for both groups, with no significant differences between the Light and No-light groups at any interval. CONCLUSION: The whitening effect was improved by approximately 26% when the Zoom2 dental whitening lamp was used. It was demonstrated that the a photo-Fenton activator used with a bleaching light and 20% hydrogen peroxide gel is safe and effective for whitening teeth rapidly.     

Presence and antibiotic resistance of Porphyromonas gingivalis,Prevotella intermedia,and Prevotella nigrescens in children

BACKGROUND/AIMS: Only limited information exists about the prevalence in children of pathogens associated with periodontitis. The aim of the present study was to determine by culture whether 8-11-year-old children carry Porphyromonas gingivalis, Prevotella intermedia, and/or P. nigrescens in samples from the gingiva and/or the buccal mucosa taken before, and after caries treatment and oral hygiene instruction. A second aim was to assess the proportion of subjects who had gram-negative anaerobes carrying the tet(Q) and erm(F) genes, suggesting antibiotic resistance to tetracycline or erythromycin. METHOD: A total of 150 children provided gingival and buccal swab bacterial samples that were cultured for P. gingivalis, P. intermedia, and P. nigrescens. The species was verified using DNA-DNA hybridization with species-specific probes made from the variable region of the 16S rRNA sequences. Antibiotic-resistant genes, tet(Q) and erm(F), were identified using specific DNA-DNA hybridization with specific DNA probes. RESULTS: A total of 116 isolates of black-pigmented bacteria were cultured from 47 (31%) of 150 children. Five isolates were identified as P. gingivalis, 29 as P. intermedia, 33 as P. nigrescens, and 49 as other species. In general, the bacteria were not culturable at more than one time period. We found that 55% of these 47 children harbored black pigmented bacteria that carried either one or both of the two antibiotic-resistant genes studied (tet(Q), and erm(F)). CONCLUSION: The present study demonstrated that children not exposed to regular dental treatment carry bacteria outside the gingival sulcus that have been associated with periodontitis, and that standard treatment procedures may not clear the presence of the putative pathogens. In addition, antibiotic-resistant genes are common in identifiable gram-negative anaerobes, including putative pathogens.     

Neurohormone activation

Neurohormonal activation plays a significant role in left ventricular remodeling and progression of heart failure. Treatment strategies that antagonize the RAS and sympathetic nervous system can attenuate the left ventricular remodeling process. Natriuretic peptides, specifically BNP, are a marker of left ventricular dysfunction. With the progressive increase in the incidence and prevalence of heart failure, treatment approaches must focus on the underlying cause as well as on blocking the neurohormonal activation that leads to the remodeling process.     

Research methods: managing primary study quality in meta-analyses

Meta-analyses synthesize multiple primary studies and identify patterns of relationships. Differences in primary study methodological quality must be addressed for meta-analysis to produce meaningful results. No single standard exists for addressing these quality variations. Quality measurement scales are fraught with development and application problems. Several strategies have been proposed to address quality. Researchers can set minimum levels for inclusion or require that certain quality attributes be present. An inclusive method is to weight effect sizes by quality scores. This allows the inclusion of diverse studies but relies on questionable quality measures. By considering quality an empirical question, meta-analysts can examine associations between quality and effect sizes and thus preserve the purpose of meta-analysis to systematically examine data. Researchers increasingly are combining strategies to overcome the limitations of using a single approach. Future work to develop valid measures of primary study quality dimensions will improve the ability of meta-analysis to inform research and nursing practice.     

Allelic resolution NGS HLA typing of Class I and Class II loci and haplotypes in Cape Town,South Africa

The development of next-generation sequencing (NGS) methods for HLA genotyping has already had an impact on the scope and precision of HLA research. In this study, allelic resolution HLA typing was obtained for 402 individuals from Cape Town, South Africa. The data were produced by high-throughput NGS sequencing as part of a study of T-cell responses to Mycobacterium tuberculosis in collaboration with the University of Cape Town and Stanford University. All samples were genotyped for 11 HLA loci, namely HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1, -DRB3, -DRB4, and -DRB5. NGS HLA typing of samples from Cape Town inhabitants revealed a unique cohort, including unusual haplotypes, and 22 novel alleles not previously reported in the IPD-IMGT/HLA Database. Eight novel alleles were in Class I loci and 14 were in Class II. There were 62 different alleles of HLA-A, 72 of HLA-B, and 47 of HLA-C. Alleles A123:17, A143:01, A129:11, A168:27:01, A101:23, B114:01:01, B115:10:01, B139:10:01, B145:07, B182:02:01 and C108:04:01 were notably more frequent in Cape Town compared to other populations reported in the literature. Class II loci had 21 different alleles of DPA1, 46 of DPB1, 27 of DQA1, 26 of DQB1, 41 of DRB1, 5 of DRB3, 4 of DRB4 and 6 of DRB5. The Cape Town cohort exhibited high degrees of HLA diversity and relatively high heterozygosity at most loci. Genetic distances between Cape Town and five other sub-Saharan African populations were also calculated and compared to European Americans.     

Spontaneous bilateral carotid artery dissection following cervical manipulation

We report an autopsy case of a bilateral carotid artery dissection, following cervical manipulation by a chiropractor. To establish the etiology of a cervical artery dissection is important in view of possible legal implications and to exclude hereditary disorders, since cervical artery dissection has been linked to several arteriopathies. The underlying arteriopathy in the presented case was an idiopathic cystic medial degeneration. This report emphasizes the role of the pathologist in defining the underlying arteriopathy in carotid artery dissection.