Helper T cells (CD3+/CD4+) within the autologous peripheral blood stem cell graft positively correlate with event free survival of multiple myeloma patients

The microenvironment in the bone marrow — including lymphocytes — is part of the pathophysiology of multiple myeloma (MM). High dose chemotherapy followed by autologous stem cell transplantation is standard of care for younger patients. Aim: To determine the influence of reinfused lymphocyte subsets on event free survival (EFS) and overall survival (OS). Methods: In peripheral blood (PB) and aphaeresis products (AP) of 41 MM patients lymphocyte subsets were determined by flow cytometry and were correlated with clinical outcome. Results: PB lymphocyte subsets did not influence EFS or OS. Residual plasma cells in the AP were not correlated with poor outcome, whereas a high percentage of B cells (CD19+) showed a trend towards reduced EFS (P = 0.051). A high amount of CD4 cells and an increased CD4/CD8 ratio were significantly associated with prolonged EFS. In contrast, high percentage of HLA-DR positive lymphocytes showed negative impact on EFS and OS (P = 0.03 and 0.02, respectively). Conclusion: Obtained data suggest the non-activated (HLA-DR negative) helper CD4+ T cells in the AP to be tumour protective.Микроокружение в костном мозге, включая лимфоциты, оказывает влияние на патофизиологию множественной миеломы (MM). Высокодозовая химиотерапия, за которой следует аутологическая трансплантация стволовых клеток, является стандартным подходом при лечении более молодых пациентов. Цель: изучить влияние введенных субпопуляций лимфоцитов на безрецидивную выживаемость (EFS) и общую выживаемость больных c ММ. Методы: методом проточной цитофлуориметрии в периферической крови (PB) и продуктах афереза (АР) пациентов с ММ ( n = 41) изучали субпопуляции лимфоцитов и возможную корреляцию с исходом болезни. Результаты: субпопуляции лимфоцитов РB не влияли на EFS или OS. Остаточные клетки плазмы в АР не коррелировали с плохим прогнозом, в тоже время при высоком содержании В-клеток (CD19+) отмечали тенденцию к снижению EFS (P = 0,051). Высокое содержание CD4-клеток и увеличение соотношения CD4/CD8 были достоверно ассоциированы с повышением EFS. В отличие от этого, высокий процент HLADR-положительных лимфоцитов имел отрицательное влияние на EFS и OS (P = 0,03 и 0,02 соответственно). Выводы: полученные данные позволяют предположить, что неактивированные (HLA-DR-отрицательные) хелперные CD4+ T-клетки в AP могут обладать антиопухолевыми свойствами

Learning to diagnose collaboratively – Effects of adaptive collaboration scripts in agent-based medical simulations

We investigated how medical students' collaborative diagnostic reasoning, particularly evidence elicitation and sharing, can be facilitated effectively using agent-based simulations. Providing adaptive collaboration scripts has been suggested to increase effectiveness, but existing evidence is diverse and could be affected by unsystematic group constellations. Collaboration scripts have been criticized for undermining learners' agency. We investigate the effect of adaptive and static scripts on collaborative diagnostic reasoning and basic psychological needs. We randomly allocated 160 medical students to one of three groups: adaptive, static, or no collaboration script. We found that learning with adaptive collaboration scripts enhanced evidence sharing performance and transfer performance. Scripting did not affect learners’ perceived autonomy and social relatedness. Yet, compared to static scripts, adaptive scripts had positive effects on perceived competence. We conclude that for complex skills complementing agent-based simulations with adaptive scripts seems beneficial to help learners internalize collaboration scripts without negatively affecting basic psychological needs

Determination of intrarenal resistance index (RI) in patients with multiple myeloma

<p>Abstract</p> <p>Background</p> <p>Renal impairment is a common complication of multiple myeloma occuring in up to 50% of patients at some stage in their disease. Due to occurrence of cast nephropathies we hypothesized circulatory dysregulation (vasoconstriction) in the kidneys with measurable elevation of the resistance index among these patients which would have a diagnostic impact.</p> <p>Subjects and methods</p> <p>36 patients with treated multiple myeloma (21 females, 15 males, mean age 61.6 ± 8.5 years) were prospectively examined by conventional abdominal ultrasound with focussed investigation of the kidneys. First, length of the organs, parenchymal width and characterization of parenchymal echogenicity were determined. Then, intrarenal RI values were measured in segmental and arcuate arteries, respectively, in both kidneys. Additionally, serum creatinine, BUN and GFR of each patient were evaluated. RI values were compared to values of 78 healthy control subjects.</p> <p>Results</p> <p>Mean renal RI was 0.68 ± 0.07 which was slightly higher than in controls with 0.62 ± 0.05, but without statistical significance. Due to the laboratory analyses patients were subdivided in those with normal (group 1, n = 21) and those with impaired (group 2, n = 15) renal function. In both groups kidney size and parenchymal width were normal. Significant more group 2 patients (60%) revealed hyperechogenic par enchyma than group 1 patients (24%) (p < 0.01). Mean renal RI indices were 0.67 ± 0.06 (right) and 0.69 ± 0.06 (left) in group 1 patients and 0.71 ± 0.08 (right) and 0.71 ± 0.07 (left) in group 2 patients and showed no significant difference (p = 0.06 and 0.15).</p> <p>Conclusion</p> <p>Renal RI values are not significantly elevated in patients with multiple myeloma even in those with renal impairment so that no hints to a relevant vasoconstriction could be evaluated. RI seems not to be a relevant parameter for the diagnosis of cast nephro pathy of multiple myeloma patients. Routinely performed ultrasound examination should be more focussed on the qualification of parenchymal echogenicity.</p

Cell-cell contact mediated signalling — no fear of contact

Cancer research with sole focus on the cancer cell and possibly growth factors cannot faithfully reproduce the environmental interaction, such as adhesion of tumor cells to e.g. stromal cells, which may determine the response of these tumors to therapy. Methodologically cell adhesion studies are often difficult since complete but careful detachment is the prerequisite for most signal transduction assays. We describe for the first time an alternative method for the co-incubation of multiple myeloma cells on long term primary bone marrow stromal cultures using the bone marrow stromal cell line HS-5. The methods are precisely described, advantages and disadvantages are discussed, and troubleshooting advises are given.Исследования роста опухолевых клеток in vitro не отражают многих факторов (взаимодействие клеток с окружающей средой, их адгезию к клеткам стромы), которые в свою очередь могут определять чувствительность опухоли к терапии. Методологически изучение клеточной адгезии часто бывает затруднено, так как разделение клеток является основой большинства методик по изучению передачи сигнала. Впервые описан альтернативный метод ко-культивирования клеток множественной миеломы с клетками стромы линии HS-5, полученных из клеток костного мозга. Приведено подробное описание, преимущества и недостатки этого метода с детальными техническими рекомендациями

Knowledge is not enough to solve the problems - The role of diagnostic knowledge in clinical reasoning activities

BACKGROUND: Clinical reasoning is a key competence in medicine. There is a lack of knowledge, how non-experts like medical students solve clinical problems. It is known that they have difficulties applying conceptual knowledge to clinical cases, that they lack metacognitive awareness and that higher level cognitive actions correlate with diagnostic accuracy. However, the role of conceptual, strategic, conditional, and metacognitive knowledge for clinical reasoning is unknown. METHODS: Medical students (n = 21) were exposed to three different clinical cases and instructed to use the think-aloud method. The recorded sessions were transcribed and coded with regards to the four different categories of diagnostic knowledge (see above). The transcripts were coded using the frequencies and time-coding of the categories of knowledge. The relationship between the coded data and accuracy of diagnosis was investigated with inferential statistical methods. RESULTS: The use of metacognitive knowledge is correlated with application of conceptual, but not with conditional and strategic knowledge. Furthermore, conceptual and strategic knowledge application is associated with longer time on task. However, in contrast to cognitive action levels the use of different categories of diagnostic knowledge was not associated with better diagnostic accuracy. CONCLUSIONS: The longer case work and the more intense application of conceptual knowledge in individuals with high metacognitive activity may hint towards reduced premature closure as one of the major cognitive causes of errors in medicine. Additionally, for correct case solution the cognitive actions seem to be more important than the diagnostic knowledge categories

Learning the facts in medical school is not enough: which factors predict successful application of procedural knowledge in a laboratory setting?

BACKGROUND: Medical knowledge encompasses both conceptual (facts or “what” information) and procedural knowledge (“how” and “why” information). Conceptual knowledge is known to be an essential prerequisite for clinical problem solving. Primarily, medical students learn from textbooks and often struggle with the process of applying their conceptual knowledge to clinical problems. Recent studies address the question of how to foster the acquisition of procedural knowledge and its application in medical education. However, little is known about the factors which predict performance in procedural knowledge tasks. Which additional factors of the learner predict performance in procedural knowledge? METHODS: Domain specific conceptual knowledge (facts) in clinical nephrology was provided to 80 medical students (3(rd) to 5(th) year) using electronic flashcards in a laboratory setting. Learner characteristics were obtained by questionnaires. Procedural knowledge in clinical nephrology was assessed by key feature problems (KFP) and problem solving tasks (PST) reflecting strategic and conditional knowledge, respectively. RESULTS: Results in procedural knowledge tests (KFP and PST) correlated significantly with each other. In univariate analysis, performance in procedural knowledge (sum of KFP+PST) was significantly correlated with the results in (1) the conceptual knowledge test (CKT), (2) the intended future career as hospital based doctor, (3) the duration of clinical clerkships, and (4) the results in the written German National Medical Examination Part I on preclinical subjects (NME-I). After multiple regression analysis only clinical clerkship experience and NME-I performance remained independent influencing factors. CONCLUSIONS: Performance in procedural knowledge tests seems independent from the degree of domain specific conceptual knowledge above a certain level. Procedural knowledge may be fostered by clinical experience. More attention should be paid to the interplay of individual clinical clerkship experiences and structured teaching of procedural knowledge and its assessment in medical education curricula

Effect of a Novel Nonviral Gene Delivery of BMP-2 on Bone Healing

Background. Gene therapeutic drug delivery approaches have been introduced to improve the efficiency of growth factors at the site of interest. This study investigated the efficacy and safety of a new nonviral copolymer-protected gene vector (COPROG) for the stimulation of bone healing. Methods. In vitro, rat osteoblasts were transfected with COPROG + luciferase plasmid or COPROG + hBMP-2 plasmid. In vivo, rat tibial fractures were intramedullary stabilized with uncoated versus COPROG+hBMP-2-plasmid-coated titanium K-wires. The tibiae were prepared for biomechanical and histological analyses at days 28 and 42 and for transfection/safety study at days 2, 4, 7, 28, and 42. Results. In vitro results showed luciferase expression until day 21, and hBMP-2-protein was measured from day 2 – day 10. In vivo, the local application of hBMP-2-plasmid showed a significantly higher maximum load after 42 days compared to that in the control. The histomorphometric analysis revealed a significantly less mineralized periosteal callus area in the BMP-2 group compared to the control at day 28. The rt-PCR showed no systemic biodistribution of luciferase RNA. Conclusion. A positive effect on fracture healing by nonviral BMP-2 plasmid application from COPROG-coated implants could be shown in this study; however, the effect of the vector may be improved with higher plasmid concentrations. Transfection showed no biodistribution to distant organs and was considered to be safe

Diagnostic errors by medical students: results of a prospective qualitative study

Background: Diagnostic errors occur frequently in daily clinical practice and put patients' safety at risk. There is an urgent need to improve education on clinical reasoning to reduce diagnostic errors. However, little is known about diagnostic errors of medical students. In this study, the nature of the causes of diagnostic errors made by medical students was analyzed. Methods: In June 2016, 88 medical students worked on eight cases with the chief complaint dyspnea in a laboratory setting using an electronic learning platform, in summary 704 processed cases. The diagnostic steps of the students were tracked and analyzed. Furthermore, after each case the participants stated their presumed diagnosis and explained why they came to their diagnostic conclusion. The content of these explanations was analyzed qualitatively. Results: Based on the diagnostic data gathering process and the students' explanations, eight different causes could be identified of which the lack of diagnostic skills (24%) and inadequate knowledge base (16%) were the most common. Other causes that often contributed to a diagnostic error were faulty context generation (15%) and premature closure (10%). The causes of misdiagnosis varied per case. Conclusions: Inadequate skills/knowledge and faulty context generation are the major problems in students' clinical reasoning process. These findings are valuable for improving medical education and thus reducing the frequency of diagnostic errors in students' later everyday clinical practice

Bone morphogenetic proteins − 7 and − 2 in the treatment of delayed osseous union secondary to bacterial osteitis in a rat model

Background: Bone infections due to trauma and subsequent delayed or impaired fracture healing represent a great challenge in orthopedics and trauma surgery. The prevalence of such bacterial infection-related types of delayed non-union is high in complex fractures, particularly in open fractures with additional extensive soft-tissue damage. The aim of this study was to establish a rat model of delayed osseous union secondary to bacterial osteitis and investigate the impact of rhBMP-7 and rhBMP-2 on fracture healing in the situation of an ongoing infection. Methods: After randomization to four groups 72 Sprague-Dawley rats underwent a transverse fracture of the midshaft tibia stabilized by intramedullary titanium K-wires. Three groups received an intramedullary inoculation with Staphylococcus aureus (103 colony-forming units) before stabilization and the group without bacteria inoculation served as healing control. After 5 weeks, a second surgery was performed with irrigation of the medullary canal and local rhBMP-7 and rhBMP-2 treatment whereas control group and infected control group received sterile saline. After further 5 weeks rats were sacrificed and underwent biomechanical testing to assess the mechanical stability of the fractured bone. Additional micro-CT analysis, histological, and histomorphometric analysis were done to evaluate bone consolidation or delayed union, respectively, and to quantify callus formation and the mineralized area of the callus. Results: Biomechanical testing showed a significantly higher fracture torque in the non-infected control group and the infected rhBMP-7- and rhBMP-2 group compared with the infected control group (p &lt; 0.001). RhBMP-7 and rhBMP-2 groups did not show statistically significant differences (p = 0.57). Histological findings supported improved bone-healing after rhBMP treatment but quantitative micro-CT and histomorphometric results still showed significantly more hypertrophic callus tissue in all three infected groups compared to the non-infected group. Results from a semiquantitative bone-healing-score revealed best bone-healing in the non-infected control group. The expected chronic infection was confirmed in all infected groups. Conclusions: In delayed bone healing secondary to infection rhBMP treatment promotes bone healing with no significant differences in the healing efficacy of rhBMP-2 and rhBMP-7 being noted. Further new therapeutic bone substitutes should be analyzed with the present rat model for delayed osseous union secondary to bacterial osteitis