Kinetics of nitric oxide release in neonatal and mature rat brain during endotoxemia, as studied by diethyldithiocarbamate spin trapping

Nitric oxide belongs to the most important biochemical factors affecting functions of brain and its response to pathological processes. In the beginning of the postnatal development brain reveals a unique plasticity, which is lost during maturation. This ability may influence the response of this organ to endotoxemia, and the related generation of nitric oxide. Using ferrous-diethyldithiocarbamate (Fe(DETC)2) chelate, a lipophilic spin trap for NO detection by electron paramagnetic resonance (EPR) spectroscopy we investigated the kinetics of NO production in brain and liver during endotoxemia induced by lipopolysaccharide (E. coli, i.p. 10 mg/kg) in 6- and 30-days-old Wistar rats. The NOFe(DETC)2 complex was found to give the characteristic signal, and the amplitude of the 3-rd (high-field) component of its hyperfine splitting was used to quantify the level of NO. The neonatal brains produced NO with a delay, as compared to the mature organs, and the maximal intensity of the process was found 12 hours after LPS injection, i.e. twice as late as in the case of the mature organs. In the both groups of the animals, livers revealed similar kinetics to brains, which betrays a systemic character of the phenomenon. Nevertheless, NO generation in the untreated brain varied during the neonatal period, which was, however, not confirmed for the liver. Our results indicate a strong dependence of the dynamics of the rat brain response to LPS on the progress of the postnatal development

Pulmonary metastases of the A549-derived lung adenocarcinoma tumors growing in nude mice : a multiple case study

Lung adenocarcinoma is a leading human malignancy with fatal prognosis. Ninety percent of the deaths, however, are caused by metastases. The model of subcutaneous tumor xenograft in nude mice was adopted to study the growth of control and photodynamically treated tumors derived from the human A549 lung adenocarcinoma cell line. As a side-result of the primary studies, observations on the metastasis of these tumors to the murine lungs were collected, and reported in the present paper. The metastasizing primary tumors were drained by a prominent number of lymphatic vessels. The metastatic tissue revealed the morphology of well-differentiated or trans-differentiated adenocarcinoma. Further histological and histochemical analyses demonstrated the presence of golden-brown granules in the metastatic tissue, similar to these found in the tumor tissue. In contrast to the primary tumors, the electron paramagnetic resonance spectroscopy revealed no nitric oxide - hemoglobin complexes (a source of intense paramagnetic signals), in the metastases. No metastases were found in other murine organs; however, white infarctions were identified in a single liver. Taken together, the A549-derived tumors growing subcutaneously in nude mice can metastasize and grow on site in the pulmonary tissue. Thus, they can represent an alternative for the model of induced metastatic nodule formation, following intravenous administration of the cancerous cells

Factors affecting short- and long-term survival of patients with acute coronary syndrome treated invasively using intravascular ultrasound and fractional flow reserve: Analysis of data from the Polish Registry of Acute Coronary Syndromes 2017–2020

Background: Intravascular ultrasound (IVUS) and fractional flow reserve (FFR) are invasive procedures increasingly used in acute coronary syndrome (ACS). Aims: The aim of this study was to evaluate the prevalence of IVUS and FFR use in patients with ACS in Poland and to assess the safety of these procedures, as well as their impact on short- and long-term survival. Methods and results: The retrospective study included 103849 patients enrolled in the PL-ACS registry in 2017-2020. IVUS was performed in 1,727 patients, FFR in 1,537 patients, both procedures in 37 patients. The frequency of performing FFR in ACS over the years increased from 1.3% to 1.8% (p <0.0001) and IVUS from 1.7% to 2.3% (p <0.0001). In the FFR and/or IVUS group, a similar incidence of stroke, reinfarction, target vessel revascularization and major bleeding was observed, while in-hospital mortality was lower (0% for IVUS + FFR vs. 0.9% for FFR vs. 2.3% for IVUS vs. 3.7 for no procedure; p <0.0001). FFR and IVUS did not affect the 30-day and one-year prognosis. Conclusion: In the consequent years, the number of FFR and IVUS procedures performed in patients with ACS in Poland increased. There was lower in-hospital mortality in the FFR and/or IVUS group in ACS, no differences in the incidence of stroke, reinfarction, target vessel revascularization and major bleeding were observed. Performing FFR and IVUS in ACS does not significantly affect 30-day or one-year mortality

Nitric oxide spin-trapping and NADPH-diaphorase activity in mature rat brain after injury

Traumatic brain injury (TBI) induces inflammatory reactions, and one of the essential mediators of this reaction is nitric oxide (NO). The action of this compound is still under study because no clear consensus has been reached about its exact action in the central nervous system. Further, it is unknown if, in the damaged brain, its neuroprotective activity outweighs its putative neurodegenerative properties. Using ferrous-diethyldithiocarbamate chelate, a lipophilic spin trap for NO detection by electron paramagnetic resonance (EPR) spectroscopy, we followed NO production in injured brain of mature Wistar rats. To relate changes in the amount of NO in the lesioned brain to the activity of NO synthase (NOS), this study also used NADPH-diaphorase staining. Our data show a rapid drop of NO concentration in the damaged brain below control values. This phenomenon persisted over several hours postinjury and varied with brain region. This decrease in NO concentration was accompanied by a simultaneous increase in the number of NADPH-diaphorase-positive cells, perhaps indicative of increased NOS activity. It is therefore assumed that, in the lesioned brain, a very rapid removal of NO occurs via its transformation to other reactive species such as peroxynitrite, which further adversely influence the damaged tissue

Changes in the nitric oxide level in the rat liver as a response to brain injury

Liver disturbances stimulate inflammatory reaction in the brain but little is known if injury to the brain can significantly influence liver metabolism. This problem is crucial in modern transplantology, as the condition of the donor brain seems to strongly affect the quality (viability) of the graft, which is often obtained from brain-dead donors, usually after traumatic brain injury. Because nitric oxide is one of the significant molecules in brain and liver biology, we examined if brain injury can affect NO level in the liver. Liver samples of Wistar rats were collected and studied with EPR NO-metry to detect NO level changes at different time points after brain injury. Shortly after the trauma, NO level in the liver was similar to the control. However, later there was a significant increase in the NO content in the livers starting from the 2nd day after brain injury and lasting up to the 7th day. It seems that the response to a mechanical brain injury is of the systemic, rather than local character. Therefore brain metabolism disturbances can influence liver metabolism at least by stimulating the organ to produce NO

Probing iso-1-cytochrome c structure by site-directed spin labeling and electron paramagnetic resonance techniques

A cysteine-specific methanethiosulfonate spin label was introduced into yeast iso-1-cytochrome c at three different positions. The modified forms of cytochrome c included: the wild-type protein labeled at naturally occurring C102, and two mutated proteins, S47C and L85C, labeled at positions 47 and 85, respectively (both S47C and L85C derived from the protein in which C102 had been replaced by threonine). All three spin-labeled protein derivatives were characterized using electron paramagnetic resonance (EPR) techniques. The continuous wave (CW) EPR spectrum of spin label attached to L85C differed from those recorded for spin label attached to C102 or S47C, indicating that spin label at position 85 was more immobilized and exhibited more complex tumbling than spin label at two other positions. The temperature dependence of the CW EPR spectra and CW EPR power saturation revealed further differences of spin-labeled L85C. The results were discussed in terms of application of the site-directed spin labeling technique in probing the local dynamic structure of iso-1-cytochrome c