Effectiveness of a home-based pulmonary rehabilitation programme in pulmonary function and health related quality of life for patients with pulmonary tuberculosis: a pilot study

Background: Patients with Pulmonary Tuberculosis (PTB) often develop impairment in pulmonary function due to anatomical changes secondary to the illness. Physiotherapy in the form of pulmonary rehabilitation has been advocated.Objective: The aim of the study was to determine whether adherence to a six-week home-based pulmonary rehabilitation programme (PRP) improved the baseline measurements of lung function, exercise tolerance and health-related quality of life (HRQoL) in patients receiving out-patient treatment for PTB.Method: A single blinded randomized control study design was used to assess the effects of a six-week home- based PRP in patients receiving treatment for PTB at a local clinic in Khayelitsha, Western Cape. We evaluated lung function by spirometry (MINATO AUTOSPIRO-model no. AZ-505), exercise tolerance using the 6-min-walk test (6MWT), the Borg exercise exertion scale and HRQoL using the EQ-5 D questionnaire in an intervention group (n=34) and a control group (n=33). The trend of the effects of the PRP on lung function was towards increases, but there was no statistical difference between the intervention and control groups at the end of the sixth week in the values of FVC (p=0.2; 95% CI -0.9 to 0.51) as well as FEV1 (p=0.1; 95% CI -0.07 to 0.51). Similar trend was observed for exercise tolerance, and there was no significant difference in HRQoL (p=0.789).Conclusion: The outcome of the study provides motivation for further consideration and implementation of a pulmonary rehabilitation programme for patients with PTB.Keywords: Pulmonary rehabilitation, pulmonary tuberculosi

Sustainability and long-term strategies in the modeling of biological processes

In this article, we intend to explore the role of using an”infinite time horizon” framework to address the issues of sustainability and long-term strategies in the control of biological processes. We use two case study models to explain why considering a fixed or moving endpoint does not lead to the desired long-term effects. The first biological model considered concerns the spread of an infectious disease and its treatment as an infinite horizon optimal control problem. The second one deals with the metronomic chemotherapy cancer treatment over the remaining lifetime horizon of the patient. The latter is consistent with the conception of cancer as a chronic disease. Both models show structural differences in the choice of the objective functional, the first one uses a stabilization functional containing a weight function, the second one contains a damage functional which involves a density function

Improvement of quality of reporting in randomised controlled trials to prevent hypotension after spinal anaesthesia for caesarean section

Hypotension is a frequent complication of spinal anaesthesia for caesarean section and can threaten the well-being of the unborn child. Numerous randomised controlled trials (RCTs) dealt with measures to prevent hypotension. The aim of this study was to determine the reporting quality of RCTs using the Consolidated Standards of Reporting Trials (CONSORT) statement since low quality can lend false credibility to a study and overestimate the effect of an intervention. We performed a systematic literature search in PubMed to identify relevant RCTs in a pre-CONSORT period (1990–1994) and a post-CONSORT period (2004–2008). A comparative evaluation was done between the two periods, and the trials were assessed for compliance with each of the 22 CONSORT items. A total of 37 RCTs was identified. The CONSORT score increased significantly (p < 0.05) from 66.7% (±12.5%) in the pre-CONSORT period to 87.4% (±6.9%) in the post-CONSORT period. A statistically significant improvement was found for eight items, including randomization, blinding and intention-to-treat analysis. The CONSORT score in the post-CONSORT era was fairly good, also in comparison to other medical fields. In the post-CONSORT era, reporting of important items improved, in particular in the domains that are crucial to avoid bias and to improve internal validity. Use of CONSORT should be encouraged in order to keep or even improve the reporting quality

The optimal lockdown intensity for COVID-19

One of the principal ways nations are responding to the COVID-19 pandemic is by lockingdown portions of their economies to reduce infectious spread. This is expensive in terms oflost jobs, lost economic productivity, and lost freedoms. So it is of interest to ask: What isthe optimal intensity with which to lockdown, and how should that intensity vary dynamicallyover the course of an epidemic? This paper explores such questions with an optimal controlmodel that recognizes the particular risks when infection rates surge beyond the healthcaresystem's capacity to deliver appropriate care. The analysis shows that four broad strategies canbe optimal, ranging from brief lockdowns that only \smooth the curve" to sustained lockdownsthat prevent infections from spiking beyond the healthcare system's capacity. Within this model,it can be optimal to have two separate periods of locking down, so returning to a lockdown afterinitial restrictions have been lifted is not necessarily a sign of failure. Relatively small changesin judgments about how to balance health and economic harms can alter dramatically whichstrategy is optimal. Indeed, there are constellations of parameters for which two or even three ofthese distinct strategies can all be optimal for the same set of initial conditions; these correspondto so-called triple Skiba points. The performance of trajectories can be highly nonlinear in thestate variables, such that for various times t, the optimal unemployment rate could be low,medium, or high, but not anywhere in between. These complex dynamics emerge naturally from modeling the COVID-19 epidemic and suggest a degree of humility in policy debates.Even people who share a common understanding of the problem's economics and epidemiologycan prefer dramatically di_erent policies. Conversely, favoring very di_erent policies is notevidence that there are fundamental disagreements

Optimizing end-labeled free-solution electrophoresis by increasing the hydrodynamic friction of the drag-tag

We study the electrophoretic separation of polyelectrolytes of varying lengths by means of end-labeled free-solution electrophoresis (ELFSE). A coarse-grained molecular dynamics simulation model, using full electrostatic interactions and a mesoscopic Lattice Boltzmann fluid to account for hydrodynamic interactions, is used to characterize the drag coefficients of different label types: linear and branched polymeric labels, as well as transiently bound micelles. It is specifically shown that the label's drag coefficient is determined by its hydrodynamic size, and that the drag per label monomer is largest for linear labels. However, the addition of side chains to a linear label offers the possibility to increase the hydrodynamic size, and therefore the label efficiency, without having to increase the linear length of the label, thereby simplifying synthesis. The third class of labels investigated, transiently bound micelles, seems very promising for the usage in ELFSE, as they provide a significant higher hydrodynamic drag than the other label types. The results are compared to theoretical predictions, and we investigate how the efficiency of the ELFSE method can be improved by using smartly designed drag-tags.Comment: 32 pages, 11 figures, submitted to Macromolecule

Chasing up and locking down the virus: Optimal pandemic interventions within a network

During the COVID-19 pandemic countries invested significant amounts of resources into its containment. In early stages of the pandemic most of the (nonpharmaceutical) interventions can be classified into two groups: (i) testing and identification of infected individuals, (ii) social distancing measures to reduce the transmission probabilities. Furthermore, both groups of measures may, in principle, be targeted at certain subgroups of a networked population. To study such a problem, we propose an extension of the SIR model with additional compartments for quarantine and different courses of the disease across several network nodes. We develop the structure of the optimal allocation and study a numerical example of three symmetric regions that are subject to an asymmetric progression of the disease (starting from an initial hotspot). Key findings include that (i) for our calibrations policies are chosen in a “flattening-the-curve,” avoiding hospital congestion; (ii) policies shift from containing spillovers from the hotspot initially to establishing a symmetric pattern of the disease; and (iii) testing that can be effectively targeted allows to reduce substantially the duration of the disease, hospital congestion and the total cost, both in terms of lives lost and economic costs

Optimal fishery with coastal catch

In many spatial resource models, it is assumed that an agent is able to harvest the resource over the complete spatial domain. However, agents frequently only have access to a resource at particular locations at which a moving biomass, such as fish or game, may be caught or hunted. Here, we analyze an infinite time‐horizon optimal control problem with boundary harvesting and (systems of) parabolic partial differential equations as state dynamics. We formally derive the associated canonical system, consisting of a forward–backward diffusion system with boundary controls, and numerically compute the canonical steady states and the optimal time‐dependent paths, and their dependence on parameters. We start with some one‐species fishing models, and then extend the analysis to a predator–prey model of the Lotka–Volterra type. The models are rather generic, and our methods are quite general, and thus should be applicable to large classes of structurally similar bioeconomic problems with boundary controls. Recommedations for Resource Managers Just like ordinary differential equation‐constrained (optimal) control problems and distributed partial differential equation (PDE) constrained control problems, boundary control problems with PDE state dynamics may be formally treated by the Pontryagin's maximum principle or canonical system formalism (state and adjoint PDEs). These problems may have multiple (locally) optimal solutions; a first overview of suitable choices can be obtained by identifying canonical steady states. The computation of canonical paths toward some optimal steady state yields temporal information about the optimal harvesting, possibly including waiting time behavior for the stock to recover from a low‐stock initial state, and nonmonotonic (in time) harvesting efforts. Multispecies fishery models may lead to asymmetric effects; for instance, it may be optimal to capture a predator species to protect the prey, even for high costs and low market values of the predators

Distribution of Brevetoxin (PbTx-3) in Mouse Plasma: Association with High-Density Lipoproteins

We investigated the brevetoxin congener PbTx-3 to determine its distribution among carrier proteins, including albumin and blood lipoproteins. Using a radiolabeled brevetoxin tracer (PbTx-3), we found that 39% of the radiolabel remained associated with components in mouse plasma after > 15 kDa cutoff dialysis. Of this portion, only 6.8% was bound to serum albumin. We also examined the binding of brevetoxin to various lipoprotein fractions. Plasma, either spiked with PbTx-3 or from mice treated for 30 min with PbTx-3, was fractionated into different-sized lipoproteins by iodixanol gradient ultracentrifugation. Each fraction was then characterized and quantified by agarose gel electrophoresis and brevetoxin radioimmunoassay, respectively. In both the in vitro and in vivo experiments, the majority of brevetoxin immunoreactivity was restricted to only those gradient fractions that contained high-density lipoproteins (HDLs). Independent confirmation of brevetoxin binding to HDLs was provided by high molecular weight (100 kDa cutoff) dialysis of [(3)H]PbTx-3 from lipoprotein fractions as well as a scintillation proximity assay using [(3)H]PbTx-3 and purified human HDLs. This information on the association of brevetoxins with HDLs provides a new foundation for understanding the process by which the toxin is delivered to and removed from tissues and may permit more effective therapeutic measures to treat intoxication from brevetoxins and the related ciguatoxins