Blood flow velocity vector field reconstruction from dual-beam bidirectional Doppler OCT measurements in retinal veins

In this paper, we demonstrate the possibility to reconstruct the actual blood flow velocity vector field in retinal microvessels from dual-beam bidirectional Doppler optical coherence tomography measurements. First, for a better understanding of measured phase patterns, several flow situations were simulated on the basis of the known dual beam measurement geometry. We were able to extract the vector field parameters that determine the measured phase pattern, allowing for the development of an algorithm to reconstruct the velocity vector field from measured phase data. In a next step, measurements were performed at a straight vessel section and at a venous convergence; the obtained phase data were evaluated by means of the new approach. For the straight vessel section, the reconstructed flow velocity vector field yielded a parabolic flow. For the venous convergence, however, the reconstructed vector field deviated from a parabolic profile, but was in very good accordance with the simulated vector field for the given vessel geometry. The proposed algorithm allows predictions of the velocity vector field. Moreover, the algorithm is also sensitive to directional changes of the flow velocity as small as <1°, thereby offering insight in the flow characteristics of the non-Newtonian fluid blood in microvessels.OCIS codes: (110.4500) Optical coherence tomography, (170.2655) Functional monitoring and imaging, (280.2490) Flow diagnostics     

Using a mobile health application to support self-management in COPD: a qualitative study

Background

Telehealth shows promise for supporting patients in managing their long-term health conditions, such as chronic obstructive pulmonary disease (COPD). However, it is currently unclear how patients, and particularly older people, may benefit from these technological interventions.

Aim

To explore patients’ expectations and experiences of using a mobile telehealth-based (mHealth) application and to determine how such a system may impact on their perceived wellbeing and ability to manage their COPD.

Design and setting

Embedded qualitative study using interviews with patients with COPD from various community NHS services: respiratory community nursing service, general practice, and pulmonary rehabilitation.

Method

An embedded qualitative study was conducted to which patients were recruited using purposive sampling to achieve maximum variation. Interviews were carried out prior to receiving the mHealth system and again after a 6-month period. Data were analysed using a grounded theory approach.

Results

The sample comprised 19 patients (aged 50–85 years) with varied levels of computer skills. Patients identified no difficulties in using the mHealth application. The main themes encapsulating patients’ experience of using the mHealth application related to an increased awareness of the variability of their symptoms (onset of exacerbation and recovery time) and reassurance through monitoring (continuity of care).

Conclusion

Patients were able to use the mHealth application, interpret clinical data, and use these within their self-management approach regardless of previous knowledge. Telehealth interventions can complement current clinical care pathways to support self-management behaviour.     

QTL Analysis of Behavior in Nine-Spined Sticklebacks (Pungitius pungitius)

The genetic architecture of behavioral traits is yet relatively poorly understood in most non-model organisms. Using an F₂-intercross (n = 283 offspring) between behaviorally divergent nine-spined stickleback (Pungitius pungitius) populations, we tested for and explored the genetic basis of different behavioral traits with the aid of quantitative trait locus (QTL) analyses based on 226 microsatellite markers. The behaviors were analyzed both separately (viz. feeding activity, risk-taking and exploration) and combined in order to map composite behavioral type. Two significant QTL—explaining on average 6 % of the phenotypic variance—were detected for composite behavioral type on the experiment-wide level, located on linkage groups 3 and 8. In addition, several suggestive QTL located on six other linkage groups were detected on the chromosome-wide level. Apart from providing evidence for the genetic basis of behavioral variation, the results provide a good starting point for finer-scale analyses of genetic factors influencing behavioral variation in the nine-spined stickleback.     

Human herpesvirus 6 is associated with status epilepticus and hyponatremia after umbilical cord blood transplantation

Status epilepticus after allogeneic hematopoietic cell transplantation (alloHCT) is rare. The authors report a case involving a 65-year-old man with nonconvulsive status epilepticus 34 days after umbilical cord blood transplantion for chronic lymphocytic leukemia. Cerebrospinal fluid and serum were positive for human herpesvirus 6 (HHV6). Magnetic resonance imaging of the brain showed symmetric T2 hyper-intensity bilaterally in the mesial temporal lobes, and T2 hyperintensi-ties and restricted diffusion of bilateral putamina. Despite aggressive anticonvulsive therapy, his seizures only abated with initiation of ganciclovir therapy. The patient completed six weeks of combination antiviral therapy (ganciclovir and foscarnet). His cognitive function gradually improved and, after prolonged rehabilitation, the patient was discharged home with residual intermittent memory loss but otherwise functional. HHV6 should be considered in the differential diagnosis of nonconvulsive status epilepticus after alloHCT, especially in patients with hyponatremia. Empirical antiviral therapy targeting HHV6 should be administered to these patients.