The effects of ryanodine receptor 1 (RYR1) mutation on plasma cytokines and catecholamines during prolonged restraint in pigs.

In the current study, plasma cytokines, including interleukin (IL) 1, IL-2, IL-6, IL-10, IL-12, interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) and catecholamines (adrenaline and noradrenaline) were evaluated during 4h restraint and recovery phase in 60 male pigs. Blood samples were collected from three groups of pigs representing different RYR1 genotypes, namely NN homozygotes (wild-type), Nn heterozygous and nn homozygous (mutant). The 4h restraint evoked an increase in plasma cytokine concentrations in each of the RYR1 genotype groups. During the restraint, the greatest concentrations of plasma IL-6, IL-10, IL-12 and TNF-α in nn homozygous pigs and IFN-γ in NN homozygous were observed. Interleukin 1, IL-2, IL-10, and TNF-α measures were positively intercorrelated in each of the three RYR1 genotype group. A positive correlation was seen between all measured cytokines (with the exception of IL-6) and plasma catecholamine concentrations in Nn heterozygous and nn homozygous pigs. The results suggest that of the cytokine parameters evaluated, IL-6, IL-10, IL-12 and TNF-α of the nn homozygous group seem to show a stronger stress-related response as compared with those of the other two (NN and Nn) groups.

Small doses of morphine can enhance NK cell cytotoxicity in pigs.

The effect of small and moderate doses of morphine (MF) on NK cell lytic activity (cytotoxicity, NKCC) ((51)Cr release test) and the number of circulating large granular lymphocytes (LGL) was evaluated in i.v. catheterized Pietrain crossbred pigs. Simultaneously, plasma cortisol (COR) (RIA method) was measured. Blood samples were collected 15, 60, 120, 180, and 240 min after i.v. injections of 0.5, 1.0 and 5.0 mg/kg of MF alone or MF pretreated with naloxone (NX, 1.0 mg/kg, i.v., 15 min before MF). It was found that MF induced dose- and time-dependent changes of NKCC. MF in a dose of 0.5 mg/kg evoked 4-fold increase in NKCC (in comparison to saline) without changes in the number of LGL/NK cells. Higher MF doses (1.0, 5.0 mg/kg) induced an early increase (up to 300Delta% and 29Delta%, respectively) followed by a decrease in cytotoxicity (to -76Delta% after 5.0 mg/kg), and in LGL number (-36Delta% after 5.0 mg/kg). These effects were concomitant with a marked rise in plasma COR (up to 234Delta% after 0.5 mg/kg and 567Delta% after 5.0 mg/kg of MF). NX pretreatment blocked all the changes in cytotoxicity but not in the LGL cell number and COR concentrations. The results indicate that MF, besides having well known immunosuppressive effects, can also enhance NKCC through the opioid receptors-dependent manner. The enhancement of cytotoxicity appears as a purely functional change independent of the recirculation of NK cells which occurs despite the high plasma concentrations of COR.

Monitoring of myocardium state during off-pump coronary artery by-pass grafting.

A measurement technique for evaluation of processes occurring in the myocardium during blood flow arrest is presented. The system is devoted to monitoring the myocardium state during off-pump coronary artery by-pass grafting, i.e. during a surgical operation performed on a beating heart. A substantial part of the system is a probe whose construction is similar to a mechanical stabilizer. Such a stabilizer is used for preventing the myocardium from moving, thus it enables stitching of the graft and artery. In comparison to the commercially available stabilizer the developed probe is enhanced with a set of electrodes. These electrodes enable simultaneous measurements of impedance and electrograms. Examples of recordings made during in vivo studies are also presented. Thus, the proposed method is applicable and potentially very useful in clinical practice.

Thermal monitoring of the myocardium under blood arrest preliminary study.

A method for monitoring the state of the myocardium during cardiosurgical interventions based on thermal IR imaging is presented. This method called Active Dynamic Thermography (ADT) uses an external excitation source to induce thermal transient processes in a tested object. Recording time series of thermograms allows to calculate parametric images - distribution of the thermal time constant at the visible surface of the myocardium - correlated to the physiology state of tested tissues. In the experiment performed the blood arrest in the left ventricle (causing in longer period heart infarct) was generated by clamping the left anterior descending artery (LAD). During LAD occlusion the ADT procedure was applied using cooling external excitation source. In summary, the calculated time constant images provide data of the tested structure and functional information of myocardium infarct. This allows to track changes in blood flow in the myocardium and inspection of the quality of the intervention during cardiosurgical procedures.

Static thermography revisited--an adjunct method for determining the depth of the burn injury.

The aim of the study was to investigate the relationship between the static thermography figure of merit DeltaT (the difference in mean values of skin area temperature for the burn wound area and the unaffected reference skin area) and a means of burn classification which would be most suitable for the choice of treatment. The work was an in vivo animal experiment. Statistical analysis showed a high correlation between the DeltaT parameter and histopathological assessment. With regard to the choice of treatment, the most useful correlation was found to be that between DeltaT and the classification of burn wounds into those healed in 3 weeks and those unhealed. The results of this study have revealed a quantitative criterion DeltaT for burn classification. The study suggests that particular burn centres using static thermography use a DeltaT parameter based on their own values for burn classification so as to group burn wounds into those that healed in 3 weeks and those that did not heal. This criterion should be independent of and replace other classification systems. A criterion for the proper choice of burn treatment would then be made more readily available.