In vitro comparison of isometric and stop-test contractility parameters for the urinary bladder

Contractility parameters in the urinary bladder can be calculated from isometric contractions (no extra patient load as compared to routine cystometry) or from stop-tests (more accurate, simpler analysis). A stop-test involves a voluntarily interrupted micturition with pressure and flow measurement. In a series of measurements in vitro on pig urinary bladder strips, parameters of the first type, obtained either by analyzing isometric contractions in terms of the Hill model, or by making phase plots, were compared to parameters of the second type. A good correlation was found. Th parameter correlating best with the maximal contraction velocity of the bladder, normalized for differences in initial muscle length, as obtained from stop-test, is the isometric contraction force, which can be obtained from an isometric contraction by either of the two analysis techniques. Clinically, making phase plots seems more promising than analyzing contractions in terms of the Hill model

The length dependence of the series elasticity of pig bladder smooth muscle

Strips of urinary bladder smooth muscle were subjected to a series of quick release measurements. Each measurement consisted of several releases and resets to the original length, made during one contraction. The complete length-force characteristic of series elasticity was quantified by estimating H, the amplitude of quick release necessary to reduce the active force to exactly zero, and Db, a measure for the deviation of the characteristic from a straight line. By measuring a series of contractions at increasing stretched strip lengths, the length dependence of these parameters was studied. It was found that H depends linearly on stretched strip length. On average H/length amounted to 0.04. Db decreased when strips were stretched, i.e. a straight line was more closely approximated. Both parameter dependencies support the concept of two separate elastic mechanisms, a linear true passive elasticity in series with a non-linear elasticity in the cross-bridges. For the latter, H amounts to 3.8% of the initial strip length

Isolation and individual electrical stimulation of single smooth-muscle cells from the urinary bladder of the pig

In contrast to striated muscle, measurements on strips of smooth muscle cannot be uniquely interpreted in terms of an array of contractile units. Therefore scaling down to the single-cell level is necessary to gain detailed understanding of the contractile process in this type of muscle. The present study describes the development of a method for isolating contractile single smooth muscle cells from pig urinary bladders. Contractile responses evoked by individual electrical stimulation were used as a measure of cell quality during development of the method. Responses were evaluated by measuring latency, contraction and relaxation times, as indicated by visible length changes, and stored on-line in a computer. Initial length, relative shortening and shortening speed were determined by measuring cell lengths in previously timed still video frames using a computer-controlled crosshair device. Increase of stimulus pulse duration resulted in improved responses, indicating that the observed shortening represented a physiological contractile response. Ultimately this method of evaluation was applied to two sets of cell preparations obtained by two different methods, one using only collagenase digestion, the other using mechanical manipulation as well. Both sets showed two main patterns of response to electrical stimulation: a pattern of contraction upon stimulation followed by enhanced contraction when stimulation was switched off (CK), and a pattern of contraction upon stimulation followed by relaxation when the stimulus was switched off (CR). The set of preparations containing the highest percentage of CR cells was found to be superior (i.e. greater initial length, shorter latency and contraction times, increased shortening and higher shortening speed). The method of isolation used for this set gives a high yield of contractile cells available for experimental use over a long span of time

Appropriate medication use in Dutch terminal care:study protocol of a multicentre stepped-wedge cluster randomized controlled trial (the AMUSE study)

Background: Polypharmacy is common among patients with a limited life expectancy, even shortly before death. This is partly inevitable, because these patients often have multiple symptoms which need to be alleviated. However, the use of potentially inappropriate medications (PIMs) in these patients is also common. Although patients and relatives are often willing to deprescribe medication, physicians are sometimes reluctant due to the lack of evidence on appropriate medication management for patients in the last phase of life. The aim of the AMUSE study is to investigate whether the use of CDSS-OPTIMED, a software program that gives weekly personalized medication recommendations to attending physicians of patients with a limited life expectancy, improves patients’ quality of life. Methods: A multicentre stepped-wedge cluster randomized controlled trial will be conducted among patients with a life expectancy of three months or less. The stepped-wedge cluster design, where the clusters are the different study sites, involves sequential crossover of clusters from control to intervention until all clusters are exposed. In total, seven sites (4 hospitals, 2 general practices and 1 hospice from the Netherlands) will participate in this study. During the control period, patients will receive ‘care as usual’. During the intervention period, CDSS-OPTIMED will be activated. CDSS-OPTIMED is a validated software program that analyses the use of medication based on a specific set of clinical rules for patients with a limited life expectancy. The software program will provide the attending physicians with weekly personalized medication recommendations. The primary outcome of this study is patients’ quality of life two weeks after baseline assessment as measured by the EORTC QLQ-C15-PAL questionnaire, quality of life question.Discussion: This will be the first study investigating the effect of weekly personalized medication recommendations to attending physicians on the quality of life of patients with a limited life expectancy. We hypothesize that the CDSS-OPTIMED intervention could lead to improved quality of life in patients with a life expectancy of three months or less. Trial registration: This trial is registered at ClinicalTrials.gov (NCT05351281, Registration Date: April 11, 2022).</p

Health-related quality of life after fast-track treatment results from a randomized controlled clinical equivalence trial

Purpose This randomized clinical equivalence trial was designed to evaluate health-related quality of life (HRQoL) after fast-track treatment for low-risk coronary artery bypass (CABG) patients. Methods Four hundred and ten CABG patients were randomly assigned to undergo either short-stay intensive care treatment (SSIC, 8 h of intensive care stay) or control treatment (care as usual, overnight intensive care stay). HRQoL was measured at baseline and 1 month, and one year after surgery using the multidimensional index of life quality (MILQ), the EQ-5D, the Beck Depression Inventory and the State-Trait Anxiety Inventory. Results At one month after surgery, no statistically significant difference in overall HRQoL was found (MILQ-score P-value = .508, overall MILQ-index P-value = .543, EQ-5D VAS P-value = .593). The scores on the MILQ-domains, physical, and social functioning were significantly higher at one month postoperatively in the SSIC group compared to the control group (P-value = .049; 95% CI: 0.01-2.50 and P-value =.014, 95% CI:0.24-2.06, respectively). However, these differences were no longer observed at long-term follow-up. Conclusions According to our definition of clinical equivalence, the HRQoL of SSIC patients is similar to patients receiving care as usual. Since safety and the financial benefits of this intervention were demonstrated in a previously reported analysis, SSIC can be considered as an adequate fast-track intensive care treatment option for low-risk CABG patients

Right ventricular function in infants with bronchopulmonary dysplasia and pulmonary hypertension: a pilot study

Premature birth and bronchopulmonary dysplasia (BPD) are risk factors for the development of echocardiographic signs of pulmonary hypertension (PH) and are associated with changes in cardiac structure and function. It is unclear whether this association persists beyond early infancy. The aims of this study are to prospectively investigate the prevalence of PH in children with severe BPD and to investigate the effect of BPD and PH on myocardial structure and function at six months corrected age. Preterm infants (gestational age ≤ 32 weeks) with severe BPD were included. Echocardiography was used to define PH and to measure speckle tracking derived longitudinal and circumferential strain of the left ventricle (LV) and right ventricle (RV). Sixty-nine infants with a median (interquartile range [IQR]) gestational age of 25.6 (24.9–26.4) weeks and a median birthweight of 770 (645–945) gram were included. Eight (12%) infants had signs of PH at six months corrected age. RV fractional area change was lower in infants with severe BPD and PH at six months compared to infants without PH (35% ± 9% vs. 43% ± 9%, P = 0.03). RV mean longitudinal systolic strain was lower in infants with severe BPD and PH compared to infants without PH (17.6% [−19.5%/−16.1%] vs. −20.9% [−25.9%/−17.9%], P = 0.04). RV size and LV longitudinal and circumferential strain in children with BPD with or without PH were similar. Signs of PH were found in 12% of infants with severe BPD at six months corrected age and the presence of PH is associated with reduced RV systolic function

Early detection and counselling intervention of asthma symptoms in preschool children: study design of a cluster randomised controlled trial

Background. Prevention of childhood asthma is an important public health objective. This study evaluates the effectiveness of early detection of preschool children with asthma symptoms, followed by a counselling intervention at preventive child health centres. Early detection and counselling is expected to reduce the prevalence of asthma symptoms and improve health-related quality of life at age 6 years. Methods/design. This cluster randomised controlled trial was embedded within the Rotterdam population-based prospective cohort study Generation R in which 7893 children (born between April 2002 and January 2006) participated in the postnatal phase. Sixteen child health centres are involved, randomised into 8 intervention and 8 control centres. Since June 2005, an early detection tool has been applied at age 14, 24, 36 and 45 months at the intervention centres. Children who met the intervention criteria received counselling intervention (personal advice to parents to prevent smoke exposure of the child, and/or referral to the general practitioner or asthma nurse). The primary outcome was asthma diagnosis at age 6 years. Secondary outcomes included frequency and severity of asthma symptoms, health-related quality of life, fractional exhaled nitric oxide and airway resistance at age 6 years. Analysis was according to the intention-to-treat principle. Data collection will be completed end 2011. Discussion. This study among preschool children provides insight into the effectiveness of early detection of asthma symptoms followed by a counselling intervention at preventive child health centres. Trial registration. Current Controlled Trials ISRCTN15790308