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Biomedical subjects

Christopher K Bichakjian

Publications and source records attributed to Christopher K Bichakjian.

9 recordsLinked to original sources
PubMed2006

Odontogenic keratocysts arise from quiescent epithelial rests and are associated with deregulated hedgehog signaling in mice and humans.

Odontogenic keratocysts in humans are aggressive, noninflammatory jaw cysts that may harbor PTCH1 mutations, leading to constitutive activity of the embryonic Hedgehog (Hh) signaling pathway. We show here that epithelial expression of the Hh transcriptional effector Gli2 is sufficient for highly penetrant keratocyst development in transgenic mice. Mouse and human keratocysts expressed similar markers, leading to tooth misalignment, bone remodeling, and craniofacial abnormalities. We detected Hh target gene expression in epithelial cells lining keratocysts from both species, implicating deregulated Hh signaling in their development. Most mouse keratocysts arose from rests of Malassez--quiescent, residual embryonic epithelial cells that remain embedded in the periodontal ligament surrounding mature teeth. In Gli2-expressing mice, these rests were stimulated to proliferate, stratify, and form a differentiated squamous epithelium. The frequent development of keratocysts in Gli2-expressing mice supports the idea that GLI transcription factor activity mediates pathological responses to deregulated Hh signaling in humans. Moreover, Gli2-mediated reactivation of quiescent epithelial rests to form keratocysts indicates that these cells retain the capacity to function as progenitor cells on activation by an appropriate developmental signal.

Animals↗
PubMed2005

Microstaging accuracy after subtotal incisional biopsy of cutaneous melanoma.

BACKGROUND: A significant portion of cutaneous melanoma may remain after subtotal incisional biopsy. The accuracy of microstaging and impact on clinical practice in this scenario are unknown. OBJECTIVE: Our purpose was to examine microstaging accuracy of an initial incisional biopsy with a significant portion of the clinical lesion remaining (> or =50%). METHODS: Patients with cutaneous melanoma, diagnosed by incisional biopsy with > or =50% of the lesion remaining, were prospectively evaluated for microstaging accuracy, comparing initial Breslow depth (BD1) to final depth (BD2) after excision of the residual lesion. Impact on prognosis and treatment was also evaluated. RESULTS: Two hundred fifty of 1783 patients (14%) presented with > or =50% residual clinical lesion after incisional biopsy. The mean BD1 was 0.66 mm; the mean BD2, 1.07 mm (P = .001). After complete excision of the residual lesion, upstaging occurred in 21% and 10% became candidates for sentinel node biopsy. CONCLUSION: An incisional biopsy with > or =50% clinical lesion remaining afterward may be inadequate for accurate microstaging of melanoma. This scenario is relatively uncommon but clinically significant.

Aged↗
PubMed2005

Patterns of Internet use and impact on patients with melanoma.

BACKGROUND: Patients with cancer and their families frequently, and increasingly, turn to outside sources for information, particularly the World Wide Web. Our objective was to examine the use of the Internet and its impact among patients with melanoma. METHODS: A prospective survey was obtained from 1613 consecutive patients with cutaneous melanoma seen at our institution between August 2001 and February 2003. Main outcome measures included the ability to access the Internet, Internet use to search for melanoma information, and responses to such Internet searches. Further analysis of whether there were differences based on age, sex, or disease severity was performed. RESULTS: Of patients with melanoma, 39% indicated that they had used the Internet to research their disease, 30% themselves and 9% had someone else do it for them. Nearly half (47%) of patients younger than 40 years researched melanoma on the Internet compared with only 12% of patients 60 years or older. Neither sex nor disease severity impacted Internet use. The vast majority of patients (94%) thought the Internet was useful, 67% believed it helped them better understand their condition, and 45% said they would recommend using the Internet to others to find information about medical conditions. Roughly a third thought it decreased their anxiety, whereas a similar proportion believed the Internet made them more anxious. Increased anxiety correlated with decreasing age and increasing disease severity. CONCLUSIONS: The use of the Internet is common among patients with melanoma. Anxiety attributed to online information about their disease suggests that clinicians caring for patients with melanoma should familiarize themselves with online melanoma information, and be proactive in assisting their patients in using this resource.

Adolescent↗
PubMed2005

The effects of a professionally produced videotape on education and anxiety/distress levels for patients with newly diagnosed melanoma: a randomized, prospective clinical trial.

OBJECTIVE: Little is known about the effects of videotape-based education on knowledge and anxiety levels among patients with melanoma. We sought to evaluate effects of a professionally produced videotape on the knowledge and distress levels among patients with newly diagnosed melanoma. Secondarily, we sought to compare these effects with those of a traditional clinic visit. METHODS: We conducted a randomized controlled trial involving 217 patients. An intervention group underwent questionnaire-based testing of melanoma knowledge and anxiety/distress levels before and after viewing an educational videotape. A control group underwent similar testing before and after a clinic visit. RESULTS: The videotape and clinical encounter significantly increased knowledge and decreased anxiety. Improvement in knowledge levels was significantly greater after viewing the videotape compared with the clinic visit, whereas anxiety levels decreased to a greater degree after the clinical encounter. Whether or not a synergistic relationship may exist between exposure to an educational videotape and a physician visit was not specifically evaluated in this study. CONCLUSION: Videotape-based education may be more effective than that provided by a clinic visit, whereas the clinical encounter appears to be more effective in alleviating patient anxiety/distress.

Anxiety↗
PubMed2005

Forehead donor site full-thickness skin graft.

BACKGROUND: Full-thickness skin grafts (FTSGs) are useful for reconstructing nasal defects. Traditional reported donor sites include the preauricular, postauricular, supraclavicular, clavicular, conchal bowl, melolabial fold, and upper eyelid skin. Selection of the "best" donor site is based on the "best" tissue match and ability to camouflage the donor scar. OBJECTIVE: The purpose was to report our experience with FTSGs harvested from the forehead for reconstruction of nasal defects following Mohs' surgery. METHODS: A retrospective query of the Mohs' surgery database was performed to identify nasal defects repaired with a FTSG harvested from the forehead skin. The research record contained the patient age and gender, defect size, and cosmetic and functional outcomes interpreted by the patient and surgeon. RESULTS: FTSGs from forehead skin were used to repair the nasal defects in three patients. The functional and cosmetic outcome of all three cases was deemed excellent by the patient and surgeon. Donor site scars were well concealed within preexisting rhytids. CONCLUSION: FTSGs harvested from the forehead, although limited in practical utility, may offer an optimal FTSG match for limited select defects while also providing an easily camouflaged donor site scar within a forehead rhytid.

Forehead↗
PubMed2002

Melanoma information on the Internet: often incomplete--a public health opportunity?

PURPOSE: To assess the accuracy and completeness of information regarding melanoma on the Internet, retrieved by use of search engines. METHODS: The first 30 uniform/universal resource locators (URLs) from each of eight search engines using the search term "melanoma" were retrieved for evaluation of accuracy and completeness using a 35-point checklist rating system instrument. Four reviewers independently rated each of 35 sites, and one reviewer rated all 74 assessable sites. Kappa statistics were used to evaluate interrater variability. RESULTS: A total of 74 assessable Web sites were evaluated. The remainder were inaccessible, link pages only, or duplicates. Thirty-five Web sites were each independently rated by four reviewers. The remaining 39 Web sites were each rated by one reviewer. The mean kappa statistic for all variables and all rater pairs for which a kappa could be calculated was 0.824, indicating excellent overall inter-rater reliability. The majority of Web sites failed to include complete information on general information, risk factors, diagnosis, treatment, prevention, and prognosis. Ten Web sites (14%) contained a total of 13 inaccuracies, most relatively minor. CONCLUSION: Medical information retrieved with the search term melanoma was likely to lack complete basic melanoma information and contained inaccuracies in 14% of sites. Health care providers can help patients by recommending comprehensive and accurate Web sites for patient review, by working to create accurate and thorough Web-based health information material, and by educating patients and the public about the variability in completeness and accuracy.

Humans↗
PubMed2002

Getting patients to the right healthcare sources: from real-world questions to strategy hubs.

To address the growing problem of novices accessing incomplete and unreliable information on the Web, this paper begins by probing the nature of strategic knowledge known by expert healthcare searchers. The analysis reveals the existence of a strategy that is focused to a specific type of healthcare question. To investigate whether there exist other similar strategies, we conduct two pilot studies. The first leads to the development of a taxonomy for skin cancer questions based on real-world questions. This taxonomy has high inter-rater agreement when tested with new real-world questions. The second pilot helps to identify 6 strategies that are specific to question types in the taxonomy. We demonstrate how these strategies can be made available to a wide range of users through a prototypical system referred to as a Strategy Portal. In conclusion, we briefly describe our current and future research to test if such a system can make patients more effective and efficient in the retrieval of reliable and relevant healthcare information on the Web.

Delivery of Health Care↗