Recovery of genomic DNA from lingual mucosal cells in sufficient quantity and quality

PURPOSE: To investigate whether genomic DNA can be purified in sufficient quantity and quality from the oral cavity. METHODS: One milliliter of peripheral blood and saliva were collected. The buccal and lingual mucosal cells were also obtained using 10 strokes with a swab or a toothbrush, respectively. All materials were centrifuged and the cells were lysed by adding sodium dodecyl-sulfate and proteinase K. The DNAs were extracted with phenol and precipitated with ethanol followed by electrophoresing on 0.8% agarose gel. The purified DNAs were digested with restriction enzyme Dpn I and Mbo I, respectively. Amplification of the IL-1A gene by PCR was carried out using the purified DNAs and electrophoresing on polyacrylamide gel. RESULTS: DNA was obtained from lingual mucosal cells collected with a toothbrush. Only about one-thirtieth of the recovered DNA was of non-human origin (bacterial contaminants from the oral cavity). Judging from the PCR amplifications of the IL-1A gene, the DNA extracted from lingual cells was of sufficient quality, in all respects indistinguishable from the DNAs extracted from the other specimen, such as peripheral blood, saliva and buccal mucosal cells collected with a swab, and in sufficient quantity. Our results indicate that it is possible to purify DNAs from lingual mucosal cells collected with a toothbrush in a simple and safe manner. Compared to DNA samples from patients by blood extraction, the described method also had the advantage of being painless and not inducing mental distress.     

Effect of post-exposure prophylaxis with oseltamivir for those in contacts with influenza patients in pediatric wards

During the influenza season, outbreaks of influenza may occur in the pediatric wards due to spread from the patients hospitalized with influenza, or from those hospitalized during the latency period and develop influenza afterwards. Post-exposure prophylaxis with neuraminidase inhibitors has been reported to be effective in preventing outbreaks among household members and nursing home residents. However, for nosocomial spread, its effectiveness and possible adverse effects are to be determined. During the 2002/2003 influenza season, we experienced a total of 3 nosocomial outbreaks of influenza in the pediatric wards in two hospitals in the Kanto district, Japan. Since the number of contacts who developed influenza had been increasing despite the isolation precaution implemented, post-exposure prophylaxis with oseltamivir (2 mg/kg/dose, maximum 75 mg/dose, once a day for 7-10 days) was implemented with a permission from the parents to terminate the outbreaks. In the outbreaks (one with influenza A, two with influenza B), a total of 29 inpatients had contact with influenza patients: among those 29, 13 were given post-exposure prophylaxis, 16 were not. Out of 16 patients who did not receive post-exposure prophylaxis, 11 (69%) developed influenza: out of 13 with post-exposure prophylaxis, none developed influenza. Those patients who developed influenza were given oseltamivir (2 mg/kg/dose, maximum 75 mg/dose, twice a day for 5 days) and accommodated in a private room or a room with other patients with influenza of the same type. No significant adverse effects due to oseltamivir were observed among those who were enrolled in this study.     

Exploratory Analysis to Find Unfavorable Subset of Stage II Gastric Cancer for Which Surgery Alone Is the Standard Treatment; Another Target for Adjuvant Chemotherapy

The aim of the present study was to explore the unfavorable subset of patients with Stage II gastric cancer for whom surgery alone is the standard treatment (T1N2M0, T1N3M0, and T3N0M0). Recurrence-free survival rates were examined in 52 patients with stage T1N2-3M0 and stage T3N0M0 gastric cancer between January 2000 and March 2010. Univariate and multivariate analyses were performed to identify risk factors using a Cox proportional hazards model. The recurrence-free survival (RFS) rates of the patients with stages T1N2, T1N3, and T3N0 cancer were 80.0, 76.4, and 100% at 5 years, respectively. The only significant prognostic factor for the survival rates of the patients with stage pT1N2-3 cancer measured by univariate and multivariate analyses was pathological tumor diameter. The 5-year RFS rates of the patients with stage pT1N2-3 cancer were 60.0%, when the tumor diameters measured <30 mm, and 88.9% when the tumor diameters measured >30 mm (P = 0.0248). These data may suggest that pathological tumor diameter is associated with poor survival in patients with small T1N2-3 tumors. Because our study was a retrospective single-center study with a small sample size, a prospective multicenter study is necessary to confirm whether small tumors are risk factor for the RFS in T1N2-3 disease.Key words: Gastric cancer, Stage II, Adjuvant chemotherapyEvery year, more than 934,000 people develop gastric cancer worldwide. After lung cancer, gastric cancer is the second most frequent cancer-related cause of death.¹ Complete resection is essential to cure gastric cancer. Patients with stage II or stage III gastric cancer often develop tumor recurrence, even after complete curative resections.In 2007, the Adjuvant Chemotherapy Trial of S-1 for Gastric Cancer (ACTS-GC) phase III trial demonstrated that S-1 is effective as adjuvant chemotherapy in Japanese patients who have undergone curative D2 gastrectomy for advanced gastric cancer.² In general, patients eligible for ACTS-GC were those diagnosed with pathological stages II and III. However, patients classified with pathological (p) stages T1N2M0, T1N3M0, and T3N0M0—which are classified as part of stage II—were excluded from the ACTS-GC trial. Because in the prior phase III studies comparing surgery alone and adjuvant chemotherapy, patients with stages T1N+ and T2-3/N0 cancer had excellent prognoses with 5-year overall survival (OS) rates of more than 80% from surgery alone,^3,4 these patients were excluded from receiving adjuvant chemotherapy. Japanese Gastric Cancer Association (JGCA) guidelines clearly state that the standard treatment for these patients is surgery alone.⁵Therefore, patients with stage II gastric cancer have been divided into two groups: one for whom the standard treatment is surgery alone, and the other for whom the standard treatment is surgery and adjuvant chemotherapy with S-1. Before the advent of ACTS-GC, survival rates were poorer in the latter group than in the former. However, treatment with adjuvant chemotherapy with S-1 has reversed this trend. Now, patients in the latter group receiving S-1 adjuvant chemotherapy have 5-year OS rates of 84.2%.⁶ Therefore, it may be old rationale that dictates that patients in the former group should be excluded from receiving adjuvant chemotherapy, because the 5-year OS rates are now more than 80% by S-1 adjuvant chemotherapy in the latter group. Five-year OS rates of 80% would not be obtained by surgery alone. Among those patients with stage II gastric cancer assigned to the surgery alone group, some may have a poor prognosis and be good candidates for adjuvant chemotherapy. The aim of the present study was to explore the unfavorable subset of patients among those with stage II gastric cancer for whom surgery alone is the standard treatment (T1N2M0, T1N3M0, and T3N0M0).