Oxygen uptake kinetics during high-intensity arm and leg exercise

The purpose of the present study was to examine the oxygen uptake kinetics during heavy arm exercise using appropriate modelling techniques, and to compare the responses to those observed during heavy leg exercise at the same relative intensity. We hypothesised that any differences in the response might be related to differences in muscle fibre composition that are known to exist between the upper and lower body musculature. To test this, ten subjects completed several bouts of constant-load cycling and arm cranking exercise at 90% of the mode specific V(O(2)) peak. There was no difference in plasma [lactate] at the end of arm and leg exercise. The time constant of the fast component response was significantly longer in arm exercise compared to leg exercise (mean+/-S.D., 48+/-12 vs. 21+/-5 sec; P < 0.01), while the fast component gain was significantly greater in arm exercise (12.1+/-1.0 vs. 9.2+/-0.5 ml min(-1) W(-1); P < 0.01). The V(O(2)) slow component emerged later in arm exercise (126+/-27 vs. 95+/-20 sec; P < 0.01) and, in relative terms, increased more per unit time (5.5 vs. 4.4% min(-1); P < 0.01). These differences between arm crank and leg cycle exercise are consistent with a greater and/or earlier recruitment of type II muscle fibres during arm crank exercise.     

In vitro susceptibility to infection with SIVcpz and HIV-1 is lower in chimpanzee than in human peripheral blood mononuclear cells

This study was undertaken to evaluate and compare the susceptibility of chimpanzee versus human peripheral blood mononuclear cells (PBMCs) to infection with SIVcpz and HIV-1 non-syncitium inducing primary isolates. The results demonstrate clearly that chimpanzee PBMCs have a lower capacity to support viral replication as compared to human PBMCs. There was no experimental evidence that this difference was due to a lower availability of target cells for viral infection (PBMCs positive for CD4 and CCR5 molecules) or to a differential susceptibility to apoptosis (PBMCs positive for CD4 and CD95 molecules). A lower capacity of chimpanzee PBMCs to support SIVcpz and HIV-1 replication in vitro is related to a post-entry barrier to virus replication.     

Use of an event recorder in the decision for pacemaker implantation in a child with syncope

The use of a patient-triggered and automatic event recorder is documented in a 17-month-old girl presenting with paroxysmal episodes of loss of consciousness. After pacemaker implantation, the paroxysmal attacks disappeared. CONCLUSION: we recommend a more frequent use of the event recorder in the investigation of syncope, especially in small children.     

Evaluation of 4-mm to 7-mm versus 6-mm prosthetic brachial-antecubital forearm loop access for hemodialysis: results of a randomized multicenter clinical trial

OBJECTIVE: Prosthetic arteriovenous fistulas for hemodialysis vascular access have a high incidence rate of thrombotic occlusions that result in graft failure. This randomized multicenter study was performed to assess the patency rates and the effect of 4-mm to 7-mm grafts on the development of stenoses. METHODS: A total of 109 patients who needed vascular access for hemodialysis were randomized to receive either 6-mm (n = 57) or 4-mm to 7-mm prosthetic brachial-antecubital forearm loop accesses (polytetrafluoroethylene). Duplex scanning, with measurement of blood flow and peak systolic velocity and detection of stenoses (>50%), was performed at 1, 6, and 12 months after surgery. Clinical data were obtained in a prospective manner and primary, assisted primary, and secondary patency rates were calculated with the Kaplan-Meier life-table analysis. Statistical analysis was performed with the independent samples t test and chi(2) test. RESULTS: At 1 year, patency rates were similar for both 4-mm to 7-mm and 6-mm prostheses (primary, 46% versus 43%; assisted primary, 62% versus 58%; secondary, 87% versus 91%). The incidence rate of thrombotic occlusion was comparable for both groups (0.74/patient-year versus 0.88/patient-year; P >.05). Mean graft flow at 1, 6, and 12 months was 1416 versus 1415 mL/min, 1345 versus 1319 mL/min, and 1595 versus 1265 mL/min (P >.05) for 4-mm to 7-mm and 6-mm grafts, respectively. Also, no differences in peak systolic velocities in any part of the grafts were observed. The percentage of stenoses detected was equal in both groups at 1 year after surgery (27% versus 20%; P >.05). CONCLUSION: A 4-mm to 7-mm tapered prosthetic brachial-antecubital forearm loop access did not reduce the incidence rates of stenoses and thrombotic occlusions compared with a 6-mm prosthetic conduit. Moreover, no differences in patency rates were observed. Therefore, we believe that the 4-mm to 7-mm graft should not be used routinely for hemodialysis vascular access.     

Glycoprotein IIb/IIIa inhibitors use in the setting of primary percutaneous coronary intervention for ST elevation myocardial infarction in patients pre‐treated with newer P2Y12 inhibitors

ObjectivesWe sought to investigate the safety and potential benefit of administrating glycoprotein IIb‐IIIa inhibitors (GPIs) on top of more potent P2Y12 inhibitors.BackgroundA number of clinical trials, performed at a time when pretreatment and potent platelet inhibition was not part of routine clinical practice, have documented clinical benefits of GPI in ST‐segment elevation myocardial infarction (STEMI) patients at the cost of a higher risk of bleeding.MethodsWe used the data of a prospective, ongoing registry of patients admitted for STEMI in our center. For the purpose of this study only patients presenting for primary percutaneous coronary intervention and pretreated with new P2Y12 inhibitors (prasugrel or ticagrelor) were included. We compared patients who received GPI with those who did not.ResultsEight hundred twenty‐four STEMI patients were included in our registry; GPIs were used in 338 patients (41%). GPI patients presented more often with cardiogenic shock and Thrombolysis in myocardial infarction (TIMI) flow grade <3. GPI use was not associated with an increase in in‐hospital or 3‐month mortality. Bleeding endpoints were similar in both groups.ConclusionsOur study suggests that GPI may be used safely in combination with recent P2Y12 inhibitors in STEMI patients in association with modern primary percutaneous coronary intervention strategies (radial access and anticoagulation with enoxaparin) with similar bleeding and mortality rates at hospital discharge and 3‐month follow‐up.     

Help,I’m losing patient‐centredness! Experiences of medical students and their teachers

Medical Education 2010: 44 : 662–673 Objectives Despite all educational efforts, the literature shows an ongoing decline in patient‐centredness during medical education. This study explores the experiences of medical students and their teachers and supervisors in relation to patient‐centredness in order to gain a better understanding of the factors that determine its development. Methods We conducted 11 focus groups on the subject of learning and teaching about patient‐centredness. We then carried out a constant comparative analysis of prior theory and the qualitative data collected in the focus groups using the ‘sensitising concepts’ provided by the Attitude–Social Influence–Self‐Efficacy (ASE) model. Results Although students express positive attitudes towards patient‐centredness and acquire patient‐centred skills during medical education, this study indicates that these are not sufficient to attain the level of competent behaviour needed in today’s challenging hospital environment. Clinical clerkships do provide students with ample opportunity to encounter patients and practise patient‐centred skills. However, when students lack self‐efficacy, when they face barriers (time pressure, tiredness) or when they are surrounded by non‐patient‐centred role models and are overwhelmed by powerful experiences, they lose their patient‐centred focus. The study suggests that communication skills training protects students from negative social influences. Moreover, personal development, including developing the ability to deal with emotions and personal suffering, self‐awareness and self‐care are important qualities of the central phenomenon of the ‘doctor‐as‐person’, which is identified as a missing concept in the ASE model. The student–supervisor relationship is found to be key to learning patient‐centredness and has several functions: it facilitates the direct transmission of patient‐centred skills, knowledge and attitudes; it provides social support of students’ patient‐centred behaviour; it provides support of the ‘student‐as‐person’; it mirrors patient‐centredness by being student‐centred, and, lastly, it addresses supervisor vulnerability. Finally, participants recommend that student‐centred education and guidance be offered, self‐awareness be fostered and more opportunities to encounter patients be created, including more time in general practice. Conclusions Supportive student–doctor relationships, student‐centred education and guidance that addresses the needs of the doctor‐as‐person are central to the development of patient‐centredness. Medical education requires patient‐centred, self‐caring and self‐aware role models.     

Detection of residual neuroblastoma cells in bone marrow: comparison of flow cytometry with immunocytochemistry

BACKGROUND: Because the cytomorphologic examination of bone marrow (BM) aspirates appears not sensitive enough to detect residual neuroblastoma cells, two four-color flow cytometric assays using different combinations of CD9, CD81, CD56, CD45, and anti-GD2 were evaluated. METHODS: The sensitivity of the flow cytometric assays was assessed by spiking experiments in normal peripheral blood samples. Twenty-eight BM samples, 12 biopsies, and 3 peripheral blood stem cell (PBSC) preparations from 22 patients with neuroblastoma were analyzed. The results were compared with those of an anti-GD2 immunocytochemical reference assay. RESULTS: Flow cytometric and immunocytochemical analyses showed residual neuroblastoma cells in four BM samples. One PBSC preparation and 20 BM samples were negative for both assays. Four BM and two PBSC samples scored positive for the immunocytochemical assay but were negative for the flow cytometric tests. This was due to the limited number of cells that were flow cytometrically analyzed. A strong correlation between the flow cytometric and immunocytochemical tests was found (chi2 = 6.4, P = 0.011). CONCLUSIONS: When an equal amount of cells is analyzed, the sensitivity of the flow cytometric assays is to be about 10 times lower than that of the immunocytochemical test. However, the flow cytometric assays can be used to screen for residual cells in clinical samples with a sensitivity of one neuroblastoma cell in 10(4) to 10(5) normal mononuclear cells. Flow cytometry is simple, quick, and cost effective compared with immunocytochemistry. In addition, the flow cytometric assays can be used to screen for residual neuroblastoma cells in case of a GD2-negative primary tumor. Therefore we recommend flow cytometry for the detection of residual neuroblastoma cells.