Tapan D. Patel

Analysis of retinal cell development in chick embryo by immunohistochemistry and in ovo electroporation techniques

BackgroundRetinal cell development has been extensively investigated; however, the current knowledge of dynamic morphological and molecular changes is not yet complete.ResultsThis study was aimed at revealing the dynamic morphological and molecular changes in retinal cell development during the embryonic stages using a new method of targeted retinal injection, in ovo electroporation, and immunohistochemistry techniques. A plasmid DNA that expresses the green fluorescent protein (GFP) as a marker was delivered into the sub-retinal space to transfect the chick retinal stem/progenitor cells at embryonic day 3 (E3) or E4 with the aid of pulses of electric current. The transfected retinal tissues were analyzed at various stages during chick development from near the start of neurogenesis at E4 to near the end of neurogenesis at E18. The expression of GFP allowed for clear visualization of cell morphologies and retinal laminar locations for the indication of retinal cell identity. Immunohistochemistry using cell type-specific markers (e.g., Visinin, Xap-1, Lim1+2, Pkcα, NeuN, Pax6, Brn3a, Vimentin, etc.) allowed further confirmation of retinal cell types. The composition of retinal cell types was then determined over time by counting the number of GFP-expressing cells observed with morphological characteristics specific to the various retinal cell types.ConclusionThe new method of retinal injection and electroporation at E3 - E4 allows the visualization of all retinal cell types, including the late-born neurons, e.g., bipolar cells at a level of single cells, which has been difficult with a conventional method with injection and electroporation at E1.5. Based on data collected from analyses of cell morphology, laminar locations in the retina, immunohistochemistry, and cell counts of GFP-expressing cells, the time-line and dynamic morphological and molecular changes of retinal cell development were determined. These data provide more complete information on retinal cell development, and they can serve as a reference for the investigations in normal retinal development and diseases.

Polymorphous low‐grade adenocarcinoma of the head and neck: A population‐based study of 460 cases

Polymorphous low‐grade adenocarcinoma (PLGA) is a rare malignant neoplasm of the minor salivary glands. This study analyzes the demographic, clinicopathologic, incidence, and survival characteristics of head and neck PLGA (HN‐PLGA).

Epithelial-Myoepithelial Carcinoma of the Salivary Glands: An Analysis of 246 Cases

Objective Epithelial-myoepithelial carcinoma (EMC) is a rare neoplasm of the salivary glands. In this study, we aim to examine the demographic, clinicopathologic, and survival features of EMC using a population-based approach. Study Design and Setting Retrospective cohort study. Subjects and Methods The Surveillance, Epidemiology, and End Result (SEER) database (1973-2010) was queried for EMC of the major salivary glands. Data were analyzed with respect to various demographic and clinicopathologic factors. Survival was analyzed using the Kaplan-Meier and Cox proportional hazards models. Results In total, 246 cases were available for frequency analysis and 207 for survival analysis. Mean ± SD age at diagnosis was 63.8 ± 15.4 years. EMC affected females more frequently (57.3%). Distant metastases were present at diagnosis in only 4.5% of cases. Overall disease-specific survival (DSS) at 60, 120, and 180 months was 91.3%, 90.2%, and 80.7%, respectively. Patients with low-grade histology had significantly better survival at 180 months relative to those with high-grade tumors (90.6% vs 0.0%, P = .0246). When stratified by tumor size, patients with lesions >4 cm had the worst survival at 180 months (58.8%, P = .0003). All but 9 of the 207 cases available for survival analysis underwent surgery. A total of 85 patients (41.1%) received radiotherapy in addition to surgery. No survival benefit was noted for patients who received radiotherapy compared with those who did not (P = .4832). Conclusion This report represents the largest series of EMC to date. Despite being regarded as a low-grade, indolent tumor, a significant fraction of our cohort underwent radiotherapy in addition to surgery, with no apparent added survival benefit.

A comparative population‐based analysis of sinonasal diffuse large B‐cell and extranodal NK/T‐cell lymphomas

Diffuse large B‐cell lymphoma (DLBCL) and extranodal natural killer/T‐cell lymphoma (ENKTL) are aggressive tumors. ENTKL is very rare in the United States and often affects the nasal cavity and paranasal sinuses; DLBCL, although more common, rarely occurs in these locations. Our study aims to compare incidence and survival of these lymphomas in the sinonasal cavity.

Sinonasal squamous cell carcinoma and the prognostic implications of its histologic variants: a population-based study.

Variants of squamous cell carcinoma (SCC) make up 15% of all cases of SCC of the upper aerodigestive tract. There are 5 main histologic variants of SCC in the head and neck region: verrucous (VSCC), papillary (PSCC), spindle cell (sarcomatoid) (SCSC), basaloid (BSCC), and adenosquamous (ASC). Conventional sinonasal SCC has been studied extensively, but far less is known about its major variants.

117 Digital Substraction Angiography in CT Angiography Negative Spontaneous Subarachnoid HemorrhageA Cost-Effectiveness Analysis

Recent studies have documented the high sensitivity of CT angiography (CTA) in detecting a ruptured aneurysm in the presence of acute subarachnoid hemorrhage (SAH). The practice of digital subtraction angiography (DSA) when CTA does not reveal an aneurysm has thus been called into question. We examined the efficacy of DSA in CTA negative SAH when balanced with the costs and risks associated with the procedure.

Cost-Effectiveness Analysis of Microscopic and Endoscopic Transsphenoidal Surgery Versus Medical Therapy in the Management of Microprolactinoma in the United States.

BACKGROUND Although prolactinomas are treated effectively with dopamine agonists, some have proposed curative surgical resection for select cases of microprolactinomas to avoid life-long medical therapy. We performed a cost-effectiveness analysis comparing transsphenoidal surgery (either microsurgical or endoscopic) and medical therapy (either bromocriptine or cabergoline) with decision analysis modeling. METHODS A 2-armed decision tree was created with TreeAge Pro Suite 2012 to compare upfront transsphenoidal surgery versus medical therapy. The economic perspective was that of the health care third-party payer. On the basis of a literature review, we assigned plausible distributions for costs and utilities to each potential outcome, taking into account medical and surgical costs and complications. Base-case analysis, sensitivity analysis, and Monte Carlo simulations were performed to determine the cost-effectiveness of each strategy at 5-year and 10-year time horizons. RESULTS In the base-case scenario, microscopic transsphenoidal surgery was the most cost-effective option at 5 years from the time of diagnosis; however, by the 10-year time horizon, endoscopic transsphenoidal surgery became the most cost-effective option. At both time horizons, medical therapy (both bromocriptine and cabergoline) were found to be more costly and less effective than transsphenoidal surgery (i.e., the medical arm was dominated by the surgical arm in this model). Two-way sensitivity analysis demonstrated that endoscopic resection would be the most cost-effective strategy if the cure rate from endoscopic surgery was greater than 90% and the complication rate was less than 1%. Monte Carlo simulation was performed for endoscopic surgery versus microscopic surgery at both time horizons. This analysis produced an incremental cost-effectiveness ratio of

Squamous cell carcinoma of the maxillary sinus: A population‐based analysis

80,235 per quality-adjusted life years at 5 years and

Squamous cell carcinoma of the nasal cavity: A population-based analysis

40,737 per quality-adjusted life years at 10 years, implying that with increasing time intervals, endoscopic transsphenoidal surgery is the more cost-effective treatment strategy. CONCLUSIONS On the basis of the results of our model, transsphenoidal surgical resection of microprolactinomas, either microsurgical or endoscopic, appears to be more cost-effective than life-long medical therapy in young patients with life expectancy greater than 10 years. We caution that surgical resection for microprolactinomas be performed only in select cases by experienced pituitary surgeons at high-volume centers with high biochemical cure rates and low complication rates.

Sinonasal neuroendocrine carcinoma: a population-based analysis of incidence and survival.

Squamous cell carcinoma (SCC) accounts for > 90% of head and neck cancers and 60% to 75% of malignancies of the paranasal sinuses. The most commonly affected paranasal sinus is the maxillary. Epidemiologic, incidence, and survival trends have been studied for maxillary sinus SCC (MSSCC), but far less is known about its metastatic potential.