Should we teach linear algebra through geometry?

AbstractCan geometry help students learn linear algebra? I study this question and demonstrate that there is no obvious clear answer: geometry can be an obstacle to learning linear algebra; or it can be helpful. Geometry is helpful only under certain conditions and with a specific use of drawings. These special requirements for using geometry are apparently not much recognized in our teaching of linear algebra courses, at least in France, where my educational studies have taken place

The most efficient and effective BRCA1/2 testing strategy in epithelial ovarian cancer:Tumor-First or Germline-First?

Objective: Genetic testing in epithelial ovarian cancer (OC) is essential to identify a hereditary cause like a germline BRCA1/2 pathogenic variant (PV). An efficient strategy for genetic testing in OC is highly desired. We evaluated costs and effects of two strategies; (i) Tumor-First strategy, using a tumor DNA test as prescreen to germline testing, and (ii) Germline-First strategy, referring all patients to the clinical geneticist for germline testing.Methods: Tumor-First and Germline-First were compared in two scenarios; using real-world uptake of testing and setting implementation to 100%. Decision analytic models were built to analyze genetic testing costs (including counseling) per OC patient and per family as well as BRCA1/2 detection probabilities. With a Markov model, the life years gained among female relatives with a germline BRCA1/2 PV was investigated.Results: Focusing on real-world uptake, with the Tumor-First strategy more OC patients and relatives with a germline BRCA1/2 PV are detected (70% versus 49%), at lower genetic testing costs (€1898 versus €2502 per patient, and €2511 versus €2930 per family). Thereby, female relatives with a germline BRCA1/2 PV can live on average 0.54 life years longer with Tumor-First compared to Germline-First. Focusing on 100% uptake, the genetic testing costs per OC patient are substantially lower in the Tumor-First strategy (€2257 versus €4986).Conclusions: The Tumor-First strategy in OC patients is more effective in identifying germline BRCA1/2 PV at lower genetic testing costs per patient and per family. Optimal implementation of Tumor-First can further improve detection of heredity in OC patients.</p

Probability of detecting germline BRCA1/2 pathogenic variants in histological subtypes of ovarian carcinoma:A meta-analysis

Background: Histology restricted genetic predisposition testing of ovarian carcinoma patients is a topic of debate as the prevalence of BRCA1/2 pathogenic variants (PVs) in various histological subtypes is ambiguous. Our primary aim was to investigate the proportion of germline BRCA1/2 PVs per histological subtype. Additionally, we evaluated (i) proportion of somatic BRCA1/2 PVs and (ii) proportion of germline PVs in other ovarian carcinoma risk genes. Methods: PubMed, EMBASE and Web of Science were systematically searched and we included all studies reporting germline BRCA1/2 PVs per histological subtype. Pooled proportions were calculated using a random-effects meta-analysis model. Subsets of studies were used for secondary analyses. Results: Twenty-eight studies were identified. The overall estimated proportion of germline BRCA1/2 PVs was 16.8% (95% CI 14.6 to 19.2). Presence differed substantially among patients with varying histological subtypes of OC; proportions being highest in high-grade serous (22.2%, 95% CI 19.6 to 25.0) and lowest in clear cell (3.0%, 95% CI 1.6 to 5.6) and mucinous (2.5%, 95% CI 0.6 to 9.6) carcinomas. Somatic BRCA1/2 PVs were present with total estimated proportion of 6.0% (95% CI 5.0 to 7.3), based on a smaller subset of studies. Germline PVs in BRIP1, RAD51C, RAD51D, PALB2, and ATM were present in approximately 3%, based on a subset of nine studies. Conclusion: Germline BRCA1/2 PVs are most frequently identified in high-grade serous ovarian carcinoma patients, but are also detected in patients having ovarian carcinomas of other histological subtypes. Limiting genetic predisposition testing to high-grade serous ovarian carcinoma patients will likely be insufficient to identify all patients with a germline PV

Внутриартериальная химиотерапия в комбинированном лечении резектабельного рака желудка с метастазами в печень

В Донецком областном противоопухолевом центре разработан и внедрен способ катетеризации печеночной артерии при паллиативных операциях у больных раком желудка с метастазами в печень. По данному способу пролечено 56 больных резектабельным раком желудка с метастатическим поражением печени, что позволило увеличить продолжительность и улучшить качество жизни больных.У Донецькому обласному протипухлинному центрі розроблено та впроваджено спосіб катетеризації печінкової артерії при паліативних операціях у хворих на рак шлунку з метастазами в печінку. За цим способом проліковано 56 хворих на резектабельний рак шлунку з метастатичним ураженням печінки, що дало змогу збільшити тривалість і поліпшити якість життя хворих.A method of catheterization of hepatic artery at palliative surgery in patients with gastric cancer and metastases to the liver was worked out and introduced at Donetsk Regional Antitumor Center. This method was used in 56 patients with operable cancer of the stomach with metastases to the liver, which allowed increasing the duration and improving the quality of life of the patients

Repeated nipple fluid aspiration

Background: Despite intensive surveillance, a high rate of interval malignancies is still seen in women at increased breast cancer risk. Therefore, novel screening modalities aiming at early detection remain needed. The intraductal approach offers the possibility to directly sample fluid containing cells, DNA and proteins from the mammary ductal system where, in the majority of cases, breast cancer originates. Fluid from the breast can non-invasively be obtained by oxytocin-assisted vacuum aspiration, called nipple fluid aspiration (NFA). The goal of this feasibility study was to evaluate the potential of repeated NFA, which is a critical and essential step to evaluate its possible value as a breast cancer screening method. Methods: In this multicenter, prospective study, we annually collected nipple fluid for up to 5 consecutive years from women at increased breast cancer risk, and performed a questionnaire-based survey regarding discomfort of the aspiration. Endpoints of the current interim analyses were the feasibility and results of 994 NFA procedures in 451 women with total follow-up of 560 person years of observation. Results: In this large group of women at increased risk of breast cancer, repetitive NFA appeared to be feasible and safe. In 66.4% of aspirated breasts, nipple fluid was successfully obtained. Independent predictive factors for successful NFA were premenopausal status, spontaneous nipple discharge, smaller breast size, bilateral oophorectomy and previous use of hormone replacement therapy or anti-hormonal treatment. The procedure was well tolerated with low discomfort. Drop-out rate was 20%, which was mainly due to repeated unsuccessful aspiration attempts. Only 1.6% of women prematurely declined further participation because of side effects. Conclusions: Repeated NFA in women at increased breast cancer risk is feasible and safe. Therefore, NFA is a promising method to non-invasively obtain a valuable source of potential breast cancer specific biomarkers

'We don't know for sure':discussion of uncertainty concerning multigene panel testing during initial cancer genetic consultations

Pre-test counseling about multigene panel testing involves many uncertainties. Ideally, counselees are informed about uncertainties in a way that enables them to make an informed decision about panel testing. It is presently unknown whether and how uncertainty is discussed during initial cancer genetic counseling. We therefore investigated whether and how counselors discuss and address uncertainty, and the extent of shared decision-making (SDM), and explored associations between counselors' communication and their characteristics in consultations on panel testing for cancer. For this purpose, consultations of counselors discussing a multigene panel with a simulated patient were videotaped. Simulated patients represented a counselee who had had multiple cancer types, according to a script. Before and afterwards, counselors completed a survey. Counselors' uncertainty expressions, initiating and the framing of expressions, and their verbal responses to scripted uncertainties of the simulated patient were coded by two researchers independently. Coding was done according to a pre-developed coding scheme using The Observer XT software for observational analysis. Additionally, the degree of SDM was assessed by two observers. Correlation and regression analyses were performed to assess associations of communicated uncertainties, responses and the extent of SDM, with counselors' background characteristics. In total, twenty-nine counselors, including clinical geneticists, genetic counselors, physician assistants-in-training, residents and interns, participated of whom working experience varied between 0 and 25 years. Counselors expressed uncertainties mainly regarding scientific topics (94%) and on their own initiative (95%). Most expressions were framed directly (77%), e.g. We don't know, and were emotionally neutral (59%; without a positive/negative value). Counselors mainly responded to uncertainties of the simulated patient by explicitly referring to the uncertainty (69%), without providing space for further disclosure (66%). More experienced counselors provided less space to further disclose uncertainty (p <0.02), and clinical geneticists scored lower on SDM compared with other types of counselors (p <0.03). Our findings that counselors mainly communicate scientific uncertainties and use space-reducing responses imply that the way counselors address counselees' personal uncertainties and concerns during initial cancer genetic counseling is suboptimal

Men with metastatic prostate cancer carrying a pathogenic germline variant in breast cancer genes:disclosure of genetic test results to relatives

Some patients with metastatic prostate cancer carry a pathogenic germline variant (PV) in a gene, that is mainly associated with an increased risk of breast cancer in women. If they test positive for such a PV, prostate cancer patients are encouraged to disclose the genetic test result to relatives who are at risk in case the carrier status changes the relatives’ medical care. Our study aimed to investigate how men who learned they carry a PV in BRCA1, BRCA2, PALB2, CHEK2 or ATM disclosed their carrier status to at-risk relatives and to assess the possible psychological burden for the carrier and their perception of the burden for relatives. In total, 23 men with metastatic prostate cancer carrying a PV completed the IRI questionnaire about family communication; 14 also participated in a semi-structured interview. Patients felt highly confident in discussing the genetic test result with relatives. The diagnosis of prostate cancer was experienced as a burden, whereas being informed about genetic testing results did in most cases not add to this burden. Two patients encountered negative experiences with family communication, as they considered the genetic test result to be more urgent than their relatives. This mixed-methods study shows that metastatic prostate cancer patients with a PV in genes mainly associated with increased risk of breast cancer feel well-equipped to communicate about this predisposition in their families. Carriers felt motivated to disclose their genetic test result to relatives. Most of them indicated that the disclosure was not experienced as a psychological burden.</p

Модификации арефлюксного холедохоеюноанастомоза с восстановлением пассажа желчи в двенадцатиперстную кишку

Разработаны модификации формирования холедохоеюноанастомоза, способствующие восстановлению желчетока с пассажем желчи в двенадцатиперстную кишку, что предупреждает развитие в ней пептической язвы. Предложена специальная методика мобилизации отключенного по Ру сегмента тощей кишки, обеспечивающая его полноценную моторику.Modifications of forming choledochoanastomosis promoting restoration of bile passage to the duodenum, which prevented development of peptic ulcer, were worked out. A special technique for mobilization of the switched off segment of the jejunum according to Roux promoting an adequate motility was suggested