The relationship of gingival crevicular fluid short chain carboxylic acid concentration to gingival inflammation

Abstract Short-chain carboxylic acids (SCCA; C≤5: e.g., lactic acid, propionic acid, butyric acid) are metabolic by-products of bacterial metabolism which accumulate in the gingival crevice, and exhibit significant biological activity, including the ability to alter gene expression. It has been hypothesized that among the activities of SCCAs are their ability to contribute to gingival inflammation. This concept complements the notion that specific periodontal pathogens are the causative agents of gingival inflammation. To begin testing these 2 hypotheses, we examined the relationship between SCCA concentrations, specific putative periodontal pathogens, and gingival inflammation in medically healthy periodontally diseased subjects. We reasoned that if SCCAs and/or specific periodontal pathogens were causative gingival inflammatory agents, gingival inflammation should increase with increasing concentration of the inflammatory mediator. We also recognized that other clinical variables needed to be controlled for, and an objective quantitative assessment of gingival inflammation used. To accomplish these tasks, sites within subjects were stratified by location and pocket depth, and the following quantified: bacteria] presence; SCCA concentration: and gingival inflammation. The results indicated that gingival inflammation directly and significantly correlated with SCCA concentrations in the maxillary and mandibular molars, incisors and canines (all r≥0.47; all p≤ 0.015; too few bicuspids were available for complete analysis). The relationship between gingival inflammation and SCCA concentration was best described by a natural log relationship. Gingival inflammation did not, however, correlate positively with either the total number of specific putative periodontal pathogens, or the sum of subsets of these pathogens (?0.31 ≤r≤ 0.39; 0.08 ≤p 0.75) for any of the locations. Finally, the SCCA concentration did not correlate with the level of individual or groups of pathogens. These data, together with historical work and other preliminary data, support the hypothesis that SCCA, rather than specific putative periodontal pathogens, may be a causative agent in gingival inflammation. This work may, in part, begin to explain the apparent lack of a direct relationship between current gingival inflammation and the prediction of bacterially mediated periodontal attachment loss.     

Reduced tracheal growth after reconstruction with pericardium

Four groups of piglets were used to test the use of pericardium and periosteum as free grafts in the repair of full thickness cervical tracheal defects. Pericardium provided an airtight, rapidly healing graft, but did not give sufficient structural rigidity to prevent narrowing and growth failure at the graft site. Composite grafts of pericardium and periosteum were also unsatisfactory, in that the periosteum failed to produce enough bone to prevent collapse of the graft. Since previous studies have shown that periosteal grafts result in good bone formation when applied alone or as an extramucosal support, it is concluded that the osteogenic potential is dependent on the available blood supply and speed of revascularization. It appears that the presence of pericardium in the composite grafts may have inhibited this property.     

Challenges in nursing: infants with congenital diaphragmatic hernia.

Despite advances in the care of infants born with congenital diaphragmatic hernia, mortality rate continues to be high. Immediate survival is directly related to the degree of pulmonary hypoplasia present. The spectrum is wide, from minimal pulmonary hypoplasia, in which neonates do well, to severe pulmonary hypoplasia, which is incompatible with life. Between these two extremes lie infants with compromised pulmonary function whose long-term survival depends on the clinical strengths of their multidisciplinary team. Over the past year, 23 infants with congenital diaphragmatic hernia were cared for in the Multidisciplinary Intensive Care Unit at Children's Hospital, Boston. A retrospective chart review enabled the authors to describe the trajectory of illness and generate nursing practice guidelines. This article presents the nursing care issues that were identified in this challenging population.     

Antibodies to a synthetic peptide from the preS 120-145 region of the hepatitis B virus envelope are virus neutralizing

Studies with synthetic peptides have provided evidence for the presence of preS coded sequences in the envelope (env) proteins of hepatitis B virus (HBV) and indicated that these sequences are involved in the specific attachment of HBV to liver cells. Scanning of the preS sequence for immunodominant continuous epitopes identifies the sequence within residues preS (120-145) as the most immunogenic in eliciting antibodies recognizing HBV and as the most efficiently binding antibodies from sera of rabbits and humans immunized with HBV env proteins. To assess the potential of preS (120-145) as a synthetic vaccine against hepatitis B, in vitro neutralization of the virus by rabbit antiserum to the peptide was assayed in chimpanzees. The animals, subsequently proven to be susceptible to HBV infection, did not develop hepatitis B as judged by negative serological tests for HBV-associated antigens and antibodies and by normal serum alanine aminotransferase levels and normal liver biopsies. These results establish the role of preS domains in the process of virus neutralization and the potential of synthetic preS analogues for hepatitis B vaccination.