Antimicrobial effect of radiant catalytic ionization

The main purpose of micro-organisms elimination from the air and surfaces is to ensure microbiological safety in health care facilities or food production plants. Currently, many disinfection methods are used, both physical, chemical and, increasingly, biological. Scientists seek new solutions with high antimicrobial effectiveness (especially against the drug-resistant strains of bacteria), low production and operating costs, and, above all, the safety of patients and food consumers. The limitation of the methods used so far is primarily the micro-organisms acquire the resistance, mainly to antimicrobial agents. One of the new and alternative methods of disinfection is radiant catalytic ionization (RCI). RCI is an active method of air and surface purification. The technology proved high efficiency against viruses, Gram-positive and -negative bacteria, and fungi, both in the air and on surfaces (planktonic forms and biofilm). RCI has many advantages as well as some minor limitations. This overview summarizes the current knowledge about RCI technology.     

Triiodothyronine effect on some parameters of carbohydrate metabolism in rat blood and liver. I. In vivo effect of triiodothyronine on liver glycogen content, blood metabolites and serum glycogenolytic activity

Short (7 days) T3-treatment has no influence on the plasma glucose and FFA concentration and blood lactate level, as well as on the hepatic glycogen content in the rats. The rise in T3 levels, observed in our study, was accompanied by a fall in T4 concentrations, indicating suppression of the endogenous T4 production. On the other hand, glycogenolytic activity of rat serum in vitro is the highest in the system: control liver slices-serum of rats pretreated with T3 as compared to the system: control liver slices-control serum. These observations may lead to conclusions, that serum of rats pretreated with T3 contains factors exhibiting the greater ability to mobilize glucose from liver slices than the control serum (euthyroid). The possibility, that pretreatment with T3 may cause a decrease in the number and/or affinity of beta-adrenergic receptors in the rat liver, is discussed.     

Hyperthermia effect on lipolytic processes in rat blood and adipose tissue

Rats anaesthetized with Brevinarcon were placed in a high-temperature chamber (air temperature 50 degrees C, relative humidity 50%) for induction of hyperthermia (rectal temperature 41.0 +/- +/- 0.5 degrees C). The control group comprised rats anaesthetized in the same way but kept at room temperature. In the serum in both groups glucose, free fatty acids, immunoreactive insulin, lipolytic activity and ability to mobilize lipids in vitro were determined. It was shown that the glucose and free fatty acid levels and the activity mobilizing serum lipids in vitro in the rats subjected to hyperthermia were lower than in the control group by 12%, 23% and 150% respectively. The lipolytic activity of the serum of rats subjected to hyperthermia was 42% higher, and the level of immunoreactive insulin rose by about 224% in relation to the control group. These results point to inhibition of lipolysis in the adipose tissue with simultaneous activation of intravascular lipolysis during hyperthermia in rats.     

Effects of insulin and beta-adrenergic blockade on certain indicators of carbohydrate metabolism in the blood and tissues of rats during short-lasting hypothermia

Administration of insulin 1 i.u./100 g of body weight to hypothermic rats causes a fall of glucose and lactate levels in the serum and a rise in myocardial glycogen level in relation to the group of control rats kept at room temperature and to the group of rats subjected only to hypothermia. Beta-adrenergic blockade (propranolol 0.6-1 mg/kg) caused no changes in the levels of carbohydrate metabolites in the serum of hypothermic rats but raised the myocardial glycogen level by 42% in relation to the animals subjected only to hypothermia. Simultaneous administration of both these agents during hypothermia produces a fall of the serum levels of glucose and pyruvate with a rise in the level of lactate, and raises the glycogen level in the myocardium (by about 161%) and in the skeletal muscle (by 54%) in relation to the rats subjected to hypothermia alone. Insulin and/or propranolol fail to prevent glycogen reserve exhaustion in the liver of hypothermic rats which could be due to activation of non-blocked alpha-adrenergic receptors or to the action of yet another glycogenolytic agent, e.g. glucagon, during hypothermia.     

In vivo effect of 2-deoxy-D-glucose on glucose-6-phosphate dehydrogenase activity in the cytosol of liver, heart and skeletal muscle of rats

2-deoxy-D-glucose (2-DG), the unmetabolizable analogue of glucose induces a series of metabolic, hormonal and behavioral responses, causing cellular glucoprivation. According to in vitro studies, 2-DG inhibits phosphofructokinase in cultured human cells. The present investigations deal with changes in the cytosolic glucose-6-phosphate dehydrogenase activity following in vivo 2-DG administration. A single dose of 2-DG (600 mg/kg) has no influence on the activity of glucose-6-phosphate dehydrogenase in the cytosol of liver, heart and skeletal muscle of the rat. The concomitant increase in serum glucose, lactate and FFA concentrations observed in the study indicates indirectly a stimulation of adrenergic system. After three days of successive administration of 2-DG to rats, dehydrogenase activity decreased in the liver by approx 57% and in the skeletal muscle by approx 82% in comparison with control animals. Moreover the in vivo effect of 2-DG was found to be fully reversible, probably when the total amount of the inhibitor was excreted.     

Comparison of selected disinfectants efficiency against <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> biofilm formed on various surfaces

Listeria monocytogenes is a main etiological factor of listeriosis, spread mainly by food products. In recent years, an increasing number of patients with listeriosis and an augmentation in L. monocytogenes antibiotic resistance, e.g. to penicillin and ampicillin, has been reported. The aim of the study was to characterise the L. monocytogenes strains isolated from fish-processed food products. Species identification, based on the multiplex-PCR reaction, was performed, and the genetic similarity of the isolates was analysed with the RAPD technique. The strains, in the form of planktonic cells and a biofilm, were subjected to drug-susceptibility analysis, and the effect of disinfectants on the bacillus cells was evaluated. All of the analysed strains were of the Listeria monocytogenes species. Three genetically distant strains were detected, i.e. Lm I, Lm II and Lm III. Approximately 66.6% penicillin-resistant and 66.6% cotrimoxazole-resistant strains were found. No erythromycin-resistant strain was detected. The Lm II strain was simultaneously resistant to four antibiotics, i.e. penicillin, ampicillin, meropenem and cotrimoxazole. The strongest biofilm was formed on aluminium foil and the weakest on rubber. The tested disinfectant antibiofilm effectiveness was related to the type of surface. The most effective agent was paracetic acid and hydrogen peroxide (elimination rate 5.10–6.62 log CFU?×?cm^?2 and 5.70–7.39 log CFU?×?cm^?2 after 1- and 5-min exposure, respectively) and the least—sodium hydroxide (elimination rate 0.52–1.20 log CFU?×?cm^?2 and 0.98–1.81 log CFU?×?cm^?2 after 1- and 5-min exposure, respectively). Further studies on a greater number of L. monocytogenes strains are recommended.     

Effect of hyperthermia on blood levels of corticosterone and certain metabolites in rats during thiobutabarbital anaesthesia

No changes were found in the serum levels of corticosterone, pyruvate and lactate in rats during general anaesthesia with thiobutabarbital (Brevinarcon) subjected to short-lasting hyperthermia in a high-temperature chamber (air temperature 50 degrees C, relative humidity 50%) in relation to a control group of rats during similar general anaesthesia at room temperature. However, in the serum of rats during hyperthermia (rectal temperature 40-41 degrees C) the glucose level was about 52% lower and FFA were about 39% lower than in rats kept under normothermic conditions (rectal temperature 36.5-37.5 degrees C) which may point to an increased requirement of tissues for energy-yielding substrates at higher body temperatures and/or increased insulin secretion.     

The effects of neurotensin on selected parameters of lipid metabolism in rats

15 nM/kg b.m. of neurotensin (NT) caused a significant inhibition of LMA within 30 min of administration and this effect persisted up for to the 240 th minute of the experiment. A 15 nM/kgb.m. dose also caused a reduction in SLA which persisted up to the 120 th minute. Sixty minutes after an intraperitoneal administration of NT a decrease in the cholesterol and NEFA levels and an increase in the TG and glycerol levels were observed. These effects were inhibited by the NTR2-blocker (levocabastine) and were not subject to change after an in vivo application of SR 48692.     

In vivo effect of 2-deoxy-D-glucose on adenine nucleotide levels in the liver and skeletal muscle of rats

The present report indicates that 2-deoxy-D-glucose (2-DG) at a single dose causing reduction of Tre has no influence on liver and skeletal muscle content of ATP, ADP and AMP, the ATP/ADP ratio, energy charge potential (ECP) and total adenine nucleotides (TAN). After administration of 2-DG for 3) successive days, the level of ATP, ATP/ADP ratio, the values of ECP and TAN are decreased both in the liver and skeletal muscle. However, 72 hours after the last injection of 2-DG adenine nucleotide contents returned to the values observed in control group, indicating that the in vivo effect of this glucose analogue is fully reversible.