Long-term serum-free culture of cancer stem/progenitor cells from basal-like breast carcinoma / 中国组织工程研究

BACKGROUND: Breast cancer stem cells, a subgroup of breast cancer cells, have self-renewal and multilineage differentiation potential and are characterized as resistance to chemotherapy, radiotherapy and hypoxia, and high propensity for invasiveness and metastasis, which play an important role in the recurrence and metastasis of breast cancer. The breast cancer stem cell theory can elucidate the pathogenesis of breast cancer to a certain extent, and has great values in the selection of treatment options, the discovery of new therapeutic targets and the prognosis of breast cancer.OBJECTIVE: To isolate the breast cancer stem/progenitor cells from basal-like breast carcinoma and study their self-renewal ability, phenotype and differentiation potential over long-term serum-free suspension culture in vitro. METHODS: Twenty patients with basal-like breast cancer, including 10 patients without any treatment and 10 with neoadjuvant chemotherapy (≥ 4 cycles), were enrolled. A 1 cm3 fresh tumor tissue sample from each patient was taken and immediately sent to the laboratory to mechanically isolate tumor cells. Then, the stem/progenitor cells of basal-like breast carcinoma were enriched in ultra low attachment plates in serum free media as nonadherent mammospheres. Serial sphere formation assay was performed to determine colony formation and self-renewal ability of mammosphere-derived cells. Differentiation was induced by culturing mammosphere-derived cells in DMEM-F12 supplemented with serum but without growth factors. The proportion of CD44+/CD24- and ALDH1+ cell population was evaluated by flow cytometry. RESULTS AND CONCLUSION: The mammospheres formed after inoculation of primary basal-like breast cancer cells isolated from the tumor tissues of breast cancer patients who did not receive neoadjuvant chemotherapy cultured in the serum-free medium with growth factors, while the mammospheres could be directly isolated from the tumor specimens of patients with neoadjuvant chemotherapy. The mammosphere-derived cells could be passaged continuously to form new mammospheres. With the increase of subculture frequency, the number of adherent cells was increased, but the number of new mammospheres decreased, and the spheres became smaller and easier to adhere. The mammosphere-derived cells could be induced to differentiate in the medium supplemented with serum. The CD44+/CD24- and ALDH1+ cells were enriched in mammosphere-derived cells, and these two phenotypic cells were decreased sharply in number or absent after cell differentiation. Most of the mammosphere-derived cells after chemotherapy had stronger potentials of self-renewal and differentiation, with higher proportion of CD44+/CD24- and ALDH1+ cells. In summary, cancer cells with self-renewal and multilineage differentiation potentials exist in the basal-like breast cancer tissues. Neoadjuvant chemotherapy can enrich breast cancer stem/progenitor cells to form spheroid-like cell clusters. Some differences in biological behaviors exist between the stem/progenitor cells from different breast cancer samples, which can vary with environmental factors.

Transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis: a meta analysis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Transcatheter aortic valve implantation (TAVI) has emerged as the treatment choice for non-operable patients with severe symptomatic aortic stenosis (AS) and may be a good alternative to surgery for those at very high or prohibitive surgical risk. We performed a meta-analysis to evaluate the comparative benefits of TAVI versus surgical aortic valve replacement (SAVR) in patients with severe AS.</p><p><b>METHODS</b>A comprehensive literature search of PubMed, Embase, ScienceDirect and Cochrane Central Register of Controlled trials was performed, and randomized trials as well as cohort studies with propensity score analysis were included.</p><p><b>RESULTS</b>One randomized trial (n = 699) and six retrospective cohort studies (n = 781) were selected for meta-analysis. Mortality at 30-day and 1-year follow-up was comparable between TAVI and SAVR. Despite similar incidences of stroke, myocardial infarction, re-operation for bleeding, and renal failure requiring dialysis, TAVI was associated with a lower occurrence rate of new-onset atrial fibrillation (OR 0.51, 95%CI 0.33 - 0.78) and shorter procedural time (mean difference -67.50 minutes, 95%CI -87.20 to -47.81 minutes). Post-operative aortic regurgitation and permanent pacemaker implantation were more common in patients after TAVI than in those with SAVR (OR 5.53, 95%CI 3.41 - 8.97; OR 1.71, 95%CI 1.02 - 2.84, respectively).</p><p><b>CONCLUSION</b>In patients with severe symptomatic AS, TAVI and SAVR did not differ with respect to short- and mid-term survival, but the incidence of permanent pacemaker implantation and post-procedural aortic regurgitation remain relatively high after TAVI.</p>

Impact of prosthesis-patient mismatch on survival after mitral valve replacement: a systematic review / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To determine whether the prosthesis-patient mismatch has a deleterious impact on survival after mitral valve replacement.</p><p><b>DATA SOURCES</b>A comprehensive literature search of PubMed, Embase, and ScienceDirect was carried out. References and cited papers of relevant articles were also checked.</p><p><b>STUDY SELECTION</b>All articles published after January 1980 was initially considered. Non-English and non-human studies, case reports, and reviews were excluded from the initial search. References and cited papers of relevant articles were also checked.</p><p><b>RESULTS</b>A total of 8 retrospective cohort studies were identified for this review. The overall incidence of prosthesis-patient mismatch (<1.3 to <1.2 cm(2)/m(2)) after mitral valve replacement ranged from 3.7% to 85.9% (moderate prosthesis-patient mismatch (0.9 to 1.2 cm(2)/m(2)) in 37.4% to 69.5%, severe prosthesis-patient mismatch (<0.9 cm(2)/m(2)) in 8.7% to 16.4%). Four studies demonstrated an association of prosthesis-patient mismatch with reduced long-term survival, but the other four studies found no significant deleterious impact of prosthesis-patient mismatch after mitral valve replacement. No definite conclusion could be derived from these conflicting results.</p><p><b>CONCLUSIONS</b>Current evidence is insufficient to derive a definite conclusion whether mitral prosthesis-patient mismatch affects long-term survival because of the biases and confounding factors that interfere with late clinical outcomes. Goodquality prospective studies are warranted to evaluate the impact of mitral prosthesis-patient mismatch after mitral valve replacement in the future.</p>

Video-assisted thoracoscopic extended thymectomy for myasthenia gravis: analysis of 107 cases / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the results of video-assisted thoracoscopic extended thymectomy for myasthenia gravis.</p><p><b>METHODS</b>We retrospectively reviewed data from 107 patients received thoracoscopic extended thymectomy from June 1995 to June 2004. All patients had confirmed diagnosis of myasthenia gravis by clinical manifestation and electromyogram. Thoracoscopic extended thymectomy as well as dissection of all fatty tissue anterior to the pericardium was performed.</p><p><b>RESULTS</b>During a follow-up of 1-98 months, symptom was significantly improved in 83% of patients, including 34 patients experienced complete remission. There was no postoperative mortality.</p><p><b>CONCLUSION</b>Favorable results of video-assisted thoracoscopic extended thymectomy can be achieved in patients with myasthenia gravis. The technique is safe and minimally invasive.</p>