Recent Publications by CFE Educators

Fifteen educational innovations in academic medicine are described in relation to 5 environmental trends. The first trend, demands for increased clinical productivity, has diminished the learning environment, necessitating new organizational structures to support teaching, such as academies of medical educators, mission-based management, and faculty development. The second trend is multidisciplinary approaches to science and education. This is stimulating the growth of multidisciplinary curricular design and oversight along with integrated curricular structures. Third, the science of learning advocates the use of case-based, active learning methods; learning communities such as societies and colleges; and instructional technology. Fourth, shifting views of health and disease are encouraging the addition of new content in the curriculum. In response, theme committees are weaving content across the curriculum, new courses are being inserted into curricula, and community-based education is providing learning experiences outside of academic medical centers. Fifth, calls for accountability are leading to new forms of performance assessment using objective structured clinical exams, clinical examination exercises, simulators, and comprehensive assessment programs. These innovations are transforming medical education.

Beta-Catenin is a critical transducer of the Wnt signal pathway and plays an important role in many developmental and cellular processes. Deregulation of beta-catenin signaling has been observed in a broad range of human tumors. In this report, we investigated whether tyrosine kinase inhibitor STI-571 could inhibit the beta-catenin signaling activity and hence suppress cell proliferation. Our results demonstrated that STI-571 effectively inhibited the constitutive activity of beta-catenin signaling in human colon cancer cells as well as the Wnt1-induced activation of beta-catenin signaling in HOS, HTB-94, and HEK 293 cells. Furthermore, STI-571 was shown to effectively suppress the proliferation of human colon cancer cells. Finally, we demonstrated that the Wnt1-mediated activation of a GAL4-beta-catenin heterologous transcription system was effectively inhibited by STI-571. Thus, our findings suggest that tyrosine phosphorylation may play an important role in regulating beta-catenin signaling activity, and inhibition of this signaling pathway by STI-571 may be further explored as an important target for alternative/adjuvant treatments for a broader range of human cancer.

Although T cell activation is associated with disease progression in untreated human immunodeficiency virus type 1 (HIV-1) infection, its significance in antiretroviral-treated patients is unknown. Activated (CD38(+)HLA-DR(+)) T cell counts were measured in 99 HIV-infected adults who had maintained a plasma HIV RNA level

STUDY DESIGN

A new recombinant adenoviral vector expressing Sox9, a chondrocyte-specific transcription factor, was tested in a chondroblastic cell line and primary human intervertebral disc cells in vitro. Direct infection of intervertebral disc cells then was assessed in a rabbit model.

OBJECTIVES

To deliver a potentially therapeutic viral vector expressing Sox9 to degenerative human and rabbit intervertebral discs cells, and to assess the effect of Sox9 expression on Type 2 collagen production.

SUMMARY OF THE BACKGROUND DATA

The concentration of competent Type 2 collagen, an essential constituent of the healthy nucleus pulposus, declines with intervertebral disc degeneration. Recent studies suggest that Sox9 upregulates Type 2 collagen production. Interventions that augment Type 2 collagen production by intervertebral disc cells may represent a novel therapeutic method for patients with degenerative disc disease.

METHODS

Adenoviral delivery vectors expressing Sox9 and green fluorescent protein were constructed using the AdEasy system. The chondroblastic cell line, HTB-94, and cultured human degenerated intervertebral disc cells were infected with the vectors. Reverse transcriptase-polymerase chain reaction and immunohistochemical analyses were performed to document increased Type 2 collagen expression. The AdSox9 virus then was injected directly into the intervertebral discs of three rabbits. After 5 weeks, the injected discs were evaluated histologically.

RESULTS

The AdSox9 virus efficiently transduced HTB-94 cells and degenerated human disc cells. Western blot analysis confirmed increased Sox9 production. Increased Type 2 collagen production was demonstrated in infected HTB-94 and human disc cells using both reverse transcriptase-polymerase chain reaction and immunohistochemical staining. In the rabbit model, cells infected with AdSox9 maintained a chondrocytic phenotype, and the architecture of the nucleus pulposus was preserved over a 5-week study period compared to control discs.

CONCLUSIONS

A novel adenoviral vector efficiently increased Sox9 and Type 2 collagen synthesis in cultured chondroblastic cells and human degenerated disc cells. In a rabbit model, sustained Sox9 production preserved the histologic appearance of the nucleus pulposus cells in vivo. These findings suggest a potential role for Sox9 gene therapy in the treatment of human degenerative disc disease.

The metalloproteinase ADAMTS-2 has procollagen I N-proteinase activity capable of cleaving procollagens I and II N-propeptides in vitro, whereas mutations in the ADAMTS-2 gene in dermatosparaxis and Ehlers-Danlos syndrome VIIC show this enzyme to be responsible in vivo for most biosynthetic processing of procollagen I N-propeptides in skin. Yet despite its important role in the regulation of collagen deposition, information regarding regulation and substrate specificity of ADAMTS-2 has remained sparse. Here we demonstrate that ADAMTS-2 can, like the procollagen C-proteinases, be regulated by transforming growth factor-beta 1 (TGF-beta 1), with implications for mechanisms whereby this growth factor effects net increases in formation of extracellular matrix. TGF-beta 1 induced ADAMTS-2 mRNA approximately 8-fold in MG-63 osteosarcoma cells in a dose- and time-dependent, cycloheximide-inhibitable manner, which appeared to operate at the transcriptional level. Secreted ADAMTS-2 protein induced by TGF-beta 1 was 132 kDa and was identical in size to the fully processed, active form of the protease. Biosynthetic processing of ADAMTS-2 to yield the 132-kDa form is shown to be a two-step process involving sequential cleavage by furin-like convertases at two sites. Surprisingly, purified recombinant ADAMTS-2 is shown to cleave procollagen III N-propeptides as effectively as those of procollagens I and II, whereas processing of procollagen III is shown to be decreased in Ehlers-Danlos VIIC. Thus, the dogma that procollagen I and procollagen III N-proteinase activities are provided by separate enzymes appears to be false, whereas the phenotypes of dermatosparaxis and Ehlers-Danlos VIIC may arise from defects in both type I and type III collagen biosynthesis.

BACKGROUND

Prior studies have demonstrated that women who receive adjuvant radiation therapy (RT) after mastectomy for breast carcinoma have an increased risk of a second primary lung carcinoma after 10 years, but, to the authors' knowledge, the risk associated with adjuvant RT after breast-conserving surgery (lumpectomy) has yet to be determined. The purpose of the current study was to confirm and extend earlier findings of the effects of postmastectomy RT on second primary lung carcinoma and to investigate the impact of postlumpectomy RT on second primary lung carcinoma in the same population and to compare the results.

METHODS

The authors used data from the population-based Surveillance, Epidemiology, and End Results (SEER) program of the U.S. National Cancer Institute, encompassing approximately 10% of the U.S. population, from 1973 to 1998. Of the women with nonmetastatic invasive breast carcinoma, 194,981 had been treated with mastectomy and 65,560 were treated with lumpectomy. Cox regression analysis was used to estimate the relative risk (RR) of a second primary lung carcinoma among women treated with RT compared with those who received surgery alone as a function of time interval since treatment and laterality for both types of surgery.

RESULTS

Although no statistically significant elevation in risk for second primary lung carcinoma prior to 10 years was observed, the authors estimated a RR of 2.06 (95% confidence interval [95% CI], 1.53-2.78) and 2.09 (95% CI, 1.50-2.90) for ipsilateral lung carcinoma at 10-14 years and 15+ years after postmastectomy RT, respectively, whereas no increased risk was observed for the contralateral lung. The excess risk of ipsilateral lung carcinoma after postmastectomy RT was found for all three major histologic subtypes of lung carcinoma (adenocarcinoma, squamous cell carcinoma, and small cell carcinoma). No increased risk of lung carcinoma was observed at 10-14 years after postlumpectomy RT for either lung.

CONCLUSIONS

Postmastectomy RT was found to provide a moderate increase in risk for ipsilateral lung carcinoma starting 10 years after exposure; this increased risk is reported to persist to at least 20 years. Postlumpectomy RT does not appear to incur an increased risk. These findings should be reassuring to women treated with either type of RT, but the excess risk in the postmastectomy group should be considered in the choice between treatment options.

Iron deficiency anemia, the most common of childhood anemias, presents many challenges to the practitioner. Careful history taking that includes nutritional assessment may uncover this frequently subtle condition. In keeping with AAP recommendations, screening will aid in diagnosing this condition in populations at risk. Prompt treatment and conscientious follow-up will afford the most optimal outcome.