RESUMEN
BACKGROUND: Controversy over the issue that No. 12a lymph node involvement is distant or regional metastasis remains, and the possible inclusion of 12a lymph nodes in D2 lymphadenectomy is unclear. As reported, gastric cancer (GC) located in the lower third is highly related to the metastasis of station 12a lymph nodes. AIM: To investigate whether the clinicopathological factors and metastasis status of other perigastric nodes can predict station 12a lymph node metastasis and evaluate the prognostic significance of station 12a lymph node dissection in patients with lower-third GC. METHODS: A total of 147 patients with lower-third GC who underwent D2 or D2+ lymphadenectomy, including station 12a lymph node dissection, were included in this retrospective study from June 2003 to March 2011. Survival prognoses were compared between patients with or without station 12a lymph node metastasis. Logistic regression analyses were used to clarify the association between station 12a lymph node metastasis and clinicopathological factors or metastasis status of other perigastric nodes. The metastasis status of each regional lymph node was evaluated to identify the possible predictors of station 12a lymph node metastasis. RESULTS: Metastasis to station 12a lymph nodes was observed in 18 patients with lower-third GC, but not in 129 patients. The incidence of station 12a lymph node involvement was reported as 12.2% in patients with lower-third GC. The overall survival of patients without station 12a lymph node metastasis was significantly better than that of patients with station 12a metastasis (P < 0.001), which could also be seen in patients with or without extranodal soft tissue invasion. Station 12a lymph node metastasis and extranodal soft tissue invasion were identified as independent predictors of poor prognosis in patients with lower-third GC. Advanced pN stage was defined as independent risk factor significantly correlated with station 12a lymph node positivity. Station 3 lymph node staus was also proven to be significantly correlated with station 12a lymph node involvement. CONCLUSION: Metastasis of station 12a lymph nodes could be considered an independent prognosis factor for patients with lower-third GC. The dissection of station 12a lymph nodes may not be ignored in D2 or D2+ lymphadenectomy due to difficulties in predicting station 12a lymph node metastasis.
RESUMEN
Petiole explants were obtained from in vitro grown diploid (2x = 22) Echinacea purpurea plantlets. Shoots were regenerated by culturing the explants on MS basal medium containing 0.3 mg/L benzyladenine (BA), 0.01 mg/L naphthaleneacetic acid (NAA) and four concentrations (30, 60, 120, and 240 mg/L) of colchicine for 30 days, or 120 mg/L of colchicine for various durations (7, 14, 21, and 28 days). The regenerated shoots were induced to root on MS basal medium with 0.01 mg/L NAA, and then the root-tips of the regenerated shoots were sampled for count of chromosome number. It was found that a treatment duration of >7 days was necessary for induction of tetraploid (4x = 44) shoots, and treatment with 120 mg/L colchicine for 28 days was the most efficient for induction of tetraploids, yielding 23.5% of tetraploids among all the regenerated shoots. Chimeras were observed in almost all the treatments. However, the ratio of tetraploid to diploid cells in a chimeric plant was usually low. In comparison with diploid plants, tetraploid plants in vitro had larger stomata and thicker roots with more root branches, and had prominently shorter inflorescence stalk when mature.