Smad3 expression can be effectively silenced in vivo using a novel topical delivery system. Moreover, cutaneous Smad3 inhibition mitigates radiation-induced changes in tissue elasticity, restoring a near-normal phenotype.

The molecular methodologies used in our laboratories have allowed us to define a group of Nocardia isolates from clinical samples which resemble the type strain of Nocardia veterana. Three patient isolates and the type strain of N. veterana gave identical and distinctive restriction fragment length polymorphisms (RFLPs) for an amplified portion of the 16S rRNA gene. These three isolates and the N. veterana type strain also gave identical RFLPs for an amplified portion of the 65-kDa heat shock protein gene, but this pattern was identical to that obtained for the Nocardia nova type strain. Sequence analysis of both a 1,359-bp region of the 16S rRNA gene and a 441-bp region of the heat shock protein gene of the patient isolates showed 100% identities with the same regions of the N. veterana type strain. DNA-DNA hybridization of the DNA of one of the patient isolates with the DNA of the N. veterana type strain showed a relative binding ratio of 82%, with 0% divergence, confirming that the isolate was N. veterana. Biochemical and susceptibility testing showed no significant differences among the patient isolates and the N. veterana type strain. Significantly, the results of antimicrobial susceptibility testing obtained for our isolates were similar to those obtained for N. nova, indicating that susceptibility testing alone cannot discriminate between these species. We present two case studies which show that N. veterana is a causative agent of pulmonary disease in immunocompromised patients residing in North America. We also describe difficulties encountered in using 16S rRNA gene sequences alone for discrimination of N. veterana from the related species Nocardia africana and N. nova because of the very high degree of 16S rRNA gene similarity among them.Nocardia species have been implicated as the causes of cutaneous, ocular, pulmonary, and disseminated diseases (16) in both immunocompetent and immunocompromised human hosts. Over the past several years the spectrum of disease caused by Nocardia species has changed due to the increase in the number of immunocompromised patients. While cutaneous disease is still the most common presentation in immunocompetent individuals, such infections also occur in the immunocompromised host. However, pulmonary and disseminated infections are the more common presentations in immunocompromised individuals (16).Molecular methodologies have been instrumental in the recognition or description of several new species of Nocardia which have been recognized as human pathogens (11,(23)(24)(25)(30)(31)(32). For several years we have been using such methodologies to identify Nocardia species isolated from clinical specimens. Our procedure involves PCR amplification of portions of both the 16S rRNA gene and the 65-kDa heat shock protein (HSP) gene and subsequent restriction endonuclease analysis (REA) of the PCR products (6,20). Our experience has shown that in most cases, correct species assignment can be made when the identification obtained by REA of the 16S rRNA gene region is identical to ...

Molecular methodologies have become useful techniques for the identification of pathogenic

he 3 primary donor sites for autologous cartilage graft material in rhinoplasty and nasal reconstruction are the nasal septum, ear, and rib. Nasal septal cartilage is most commonly used owing to its ease of harvest within the surgical field without significant additional donor site morbidity. The thickness, flat contour, and durability of nasal septal cartilage are favorable qualities for long-term strength and support. Although septal cartilage is often the preferred choice in grafting material, its use may be limited by availability, particularly in noses that were previously operated on or traumatized. To overcome this problem, more recent efforts in tissue engineering have been directed toward creating new cartilage in vitro and in vivo using mesenchymal stem cells and progenitor cells seeded onto scaffolds. 1 Age-related changes in the chemical composition of human cartilage are well documented. Much of the information on this subject has been derived from studies on articular cartilage. Aging has been studied extensively in normal and osteoarthritic joint cartilage, where significant decreases in proteoglycan content are accompanied by mechanical weakening of the cartilage. 2 Although they are associated with aging, it remains unclear whether these findings are specific for degenerative and osteoarthritic cartilage rather than the normal aging process. As a result, it remains difficult to extrapolate this data to nasal cartilage, which does not undergo the same degree of mechanical stress in the nose. The notion that the quality and strength of nasal cartilage declines with advancing age is a commonly accepted be-IMPORTANCE Understanding age-related changes is important when considering cartilage-based implants or grafts during rhinoplasty and nasal reconstructive surgery. OBJECTIVE To characterize the cellular and architectural changes in human nasal cartilage with aging. DESIGN Laboratory study. PARTICIPANTS Nasal septal cartilage was harvested from 50 consecutive patients undergoing septoplasty, rhinoplasty, or septorhinoplasty. INTERVENTION Cartilage specimens were stained with hematoxylin-eosin (H&E) and safranin O for cartilage. MAIN OUTCOME MEASURES A modified Mankin histologic grading scale was used to analyze each cartilage sample for H&E findings and safranin O staining. Higher H&E scores indicated more degenerative changes, while higher safranin O scores indicated reductions in proteoglycan content within the cartilage matrix, representing decreased active chondrocyte activity. Correlation between H&E and safranin O scores and patient age was determined. RESULTS There was positive correlation between safranin O staining scores and age, with higher scores seen with advancing age (P = .01). A linear regression best-fit equation was determined to calculate a potential safranin O staining score for a given age. CONCLUSIONS AND RELEVANCE We have quantitatively determined that advancing age is positively correlated with reductions in cartilage proteoglycan content and active cartilage growth. This find...