Haloperidol affects coupling between QT and RR intervals in guinea pig isolated heart.

Prolonged QT interval is an independent risk factor for development of ventricular arrhythmias. Haloperidol is one of the drugs inducing QT prolongation. Previous studies showed that haloperidol affects not only QT duration but also heart rate (RR interval). The present work focused on relationship between QT and RR and its changes under acute and chronic haloperidol administration. The study included 14 male guinea pigs divided into control and haloperidol-treated group. After 21-days administration of haloperidol or vehiculum, electrograms in isolated hearts were recorded. QT/RR and dQT/dRR coupling were calculated. Chronic haloperidol administration significantly decreases the coupling between QT and RR. Acute haloperidol exposure significantly decreases the dQT/dRR coupling in both treated and untreated guinea pig hearts. Flatter QT/RR relationship reveals a lack of QT adaptation to increased heart rate. It should be emphasized that in such situation ECG recording will not show significant QT prolongation evaluated according to clinical rules. However, if QT interval does not adapt to increased heart rate sufficiently, the risk of ventricular arrhythmias may be increased despite practically normal QT interval length. The results are supported by findings in biochemical analyses, which proved eligibility of the used model.

Home-based training using neuromuscular electrical stimulation in patients on continuous ambulatory peritoneal dialysis: A pilot study.

There is ample evidence that maintenance of basic physical fitness through exercise training is crucial for patients with chronic renal insufficiency. Rehabilitation based on neuromuscular electrical stimulation (NMES) of thigh muscles has been shown to have many beneficial effects in patients with chronic diseases. It is likely that NMES could have beneficial effects also in patients on chronic ambulatory peritoneal dialysis (CAPD). NMES was applied for 20 weeks to 14 patients on CAPD, mean age 61.9 (8.7) years, using battery-powered stimulators (CEFAR-REHAB X2; Sweden) and self-adhesive electrodes 80 × 130 mm (PALS Platinum; Denmark). Stimulation characteristics: biphasic current, pulse width 400 µs, 8 seconds contraction-12 seconds relaxation, frequency modulation 40-60 Hz, and maximal intensity 60 mA. NMES was home-based and applied simultaneously to quadriceps muscles of both legs (2 × 30 min/day). Functional performance, muscle power (Fmax ), arterial stiffness (assessed by cardio-ankle vascular index-CAVI), and quality of life by KDQOL-SF evaluation was done at baseline and at the end of program. Home NMES improved significantly the main functional parameters: VO2peak /kg increased by +2.2 (1.6) mL O2 /kg/min (P < 0.002), peak workload by +0.1 (0.1) W/kg (P < 0.005), and distance walked in 6 MWT by +44.7 (58.4) m (P < 0.008). Only insignificant changes were observed in CAVI and Fmax . KDQOL-SF analysis showed significant improvement in seven parameters of QoL (P < 0.012-0.049). This pilot study is the first clinical report dealing with the use of NMES in patients on CAPD. The results demonstrate that an improvement of exercise capacity and QoL can be achieved by home-based NMES in CAPD patients.

Histopathology Image Analysis in Two Long-Term Animal Experiments with Helical Flow Total Artificial Heart.

Histopathological analysis can provide important information in long-term experiments with total artificial heart (TAH). Recently, a new type of blood pump, the helical flow total artificial heart (HF-TAH) was developed. This study aimed to investigate the changes in selected vital organs in animal experiments with implanted HF-TAH. Samples from lung, liver, and kidneys from two female goats (No. 1301 and No. 1304) with implanted HF-TAH were analyzed. Tissue samples were fixed in 10% formaldehyde and 4 µm thick transverse sections were stained with hematoxylin-eosin (HE). Additional staining was done for detection of connective tissue (Masson-Goldner stain) and for detection of iron (hemosiderin) deposits (Perls stain). Sections were scanned at 100× and 500× magnification with a light microscope. Experiment no. 1301 survived 100 days (cause of termination was heavy damage of the right pump); experimental goat no.1304 survived 68 days and was sacrificed due to severe right hydrodynamic bearing malfunction. Histopathological analysis of liver samples proved signs of chronic venostasis with limited focal necrotic zones. Dilated tubules, proteinaceous material in tubular lumen, and hemosiderin deposits were detected in kidney samples. Contamination of the organs by embolized micro-particles was suspected at the autopsy after discovery of visible damage (scratches) of the pump impeller surface (made from titanium alloy) in both experiments. Sporadic deposits of foreign micro-particles (presumably titanium) were observed in most of the analyzed parenchymal organs. However, the described deposits were not in direct connection with inflammatory reactions in the analyzed tissues. Histopathological analysis showed the presence of minimal contamination of the lung, kidney, and liver tissue samples by foreign material (titanium very likely). The analysis showed only limited pathological changes, especially in liver and kidneys, which might be attributed to the influence of artificial perfusion often observed in chronic TAH experiments.

Limb volume measurements: comparison of accuracy and decisive parameters of the most used present methods.

Limb volume measurements are used for evaluating growth of muscle mass and effectivity of strength training. Beside sport sciences, it is used e.g. for detection of oedemas, lymphedemas or carcinomas or for examinations of muscle atrophy. There are several commonly used methods, but there is a lack of clear comparison, which shows their advantages and limits. The accuracy of each method is uncertainly estimated only. The aim of this paper is to determine and experimentally verify their accuracy and compare them among each other. Water Displacement Method (WD), three methods based on circumferential measures-Frustum Sign Model (FSM), Disc Model (DM), Partial Frustum Model (PFM) and two 3D scan based methods Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) were compared. Precise reference cylinders and limbs of two human subjects were measured 10 times by each method. Personal dependency of methods was also tested by measuring 10 times the same object by 3 different people. Accuracies: WD 0.3 %, FSM 2-8 % according person, DM, PFM 1-8 %, MRI 2 % (hand) or 8 % (finger), CT 0.5 % (hand) or 2 % (finger);times: FSM 1 min, CT 7 min, WD, DM, PFM 15 min, MRI 19 min; and more. WD was found as the best method for most of uses with best accuracy. The CT disposes with almost the same accuracy and allows measurements of specific regions (e.g. particular muscles), as same as MRI, which accuracy is worse though, but it is not harmful. Frustum Sign Model is usable for very fast estimation of limb volume, but with lower accuracy, Disc Model and Partial Frustum Model is useful in cases when Water Displacement cannot be used.