Objectives The aim of this study was to investigate the effects of pinealectomy and melatonin treatment on the rat thymus gland characteristics, taking into consideration possible gender differences. Materials and methods Thirty adult Wistar rats of both sexes were divided into three groups. Group C and group PX served as control groups and included sham-pinealectomized and pinealectomized animals that were treated with 10% ethanol solution (0,1ml/daily, subcutaneous). Animals from third group (group PXM) underwent pinealectomy and seven days after surgery started receiving melatonin dissolved in 10% ethanol solution (3mg/kg/daily, subcutaneous). All animals were treated for 4 weeks. Results Volume density of the thymus cortex showed statistically significant (p<0,05) decrease while the volume density of the thymus medulla was increased in the pinealectomized compared to the sham-pinealectomized female rats. Numerical density of macrophages as well as the distribution of blood vessels showed no gender differences. The numerical density of lymphocytes was statistically significantly decreased in female in comparison to the male pinealectomized rats. Melatonin treatment was proved to cause reverse effects in the sense that the results from the melatonin treated group corresponded to the results obtained from the control group of animals. Conclusion The results of this study suggest that the pinealectomy causes gender-related changes in the rat thymus. Short-term melatonin treatment showed reverse effect, equally in both sexes.

The aim of this research was to assess the reactive changes of rat proximal tubules caused by gentamicin and the effect of relatively low doses of melatonin. 48 adult male Wistar rats were distributed into six groups of equal size which all received one of the following daily intraperitoneal injections: vehicle (5% ethanol in Ringer solution) during 11 days (C); gentamicin (80 mg/kg) during 8 days (G), two groups which concomitantly received gentamicin (80 mg/kg) during 8 days and melatonin in two different test doses (5 or 20 mg/kg) during 11 days (GM1, GM2) and two groups treated only with melatonin in two different doses (5 or 20 mg/kg) during 11 days (M1, M2). Histological analysis included qualitative and semi-quantitative light microscopy analysis of proximal tubules. Exogenous melatonin had no significant effect on the microstructure, independently of dosis. The changes of proximal tubules microstructure induced by gentamicin were expressed in the form of granulovacuolar degeneration, necrosis and desquamation. The grade of proximal tubular changes was smaller in animals who besides gentamicin received melatonin. Melatonin has a dose dependent protective effect on the structural alterations of proximal tubules of the kidney induced by gentamicin.

We have investigated heart type fatty acid binding protein (H-FABP) rat serum values at different time point following subcutaneous (s.c) isoproterenol (ISO) administration and their correlation with severity of myocardial lesion. Thirty adult, male, Wistar rats were used for this study. Six rats per group were treated with a single dose of either ISO (ISO groups, dose 100 mg/kg, s.c.) at different time point (30', 60', 120', 240') or with saline (control group). Serum H-FABP was determined by enzyme-linked immunosorbent assay (ELISA) and histological analysis was performed by hematoxylin-eosin (HE) method of staining. The first serum H-FABP increase was obtained 30' following ISO administration, but maximal value was reached after 240'. Myocardial histological changes were time-dependent and correlated with serum H-FABP values (p<0.001). The results of the study suggest that H-FABP is sensitive marker for acute rat myocardial injury and its possible inclusion in myocardial injury screening studies in rats.

The present study was carried out to evaluate the renoprotective antioxidant effect of Spirulina platensis on gentamicin-induced acute tubular necrosis in rats. Albino-Wistar rats, (9male and 9 female), weighing approximately 250 g, were used for this study. Rats were randomly assigned to three equal groups. Control group received 0,9 % sodium chloride intraperitoneally for 7 days at the same volume as gentamicin group. Gentamicin group was treated intraperitoneally with gentamicin, 80 mg/kg daily for 7 days. Gentamicin+spirulina group received Spirulina platensis 1000 mg/kg orally 2 days before and 7 days concurrently with gentamicin (80 mg/kg i.p.). Nephrotoxicity was assessed by measuring plasma nitrite concentration, stabile metabolic product of nitric oxide with oxygen. Plasma nitrite concentration was determined by colorimetric method using Griess reaction. For histological analysis kidney specimens were stained with hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) stain. Plasma nitrite concentration and the level of kidney damage were significantly higher in gentamicin group in comparison both to the control and gentamicin+spirulina group. Spirulina platensis significantly lowered the plasma nitrite level and attenuated histomorphological changes related to renal injury caused by gentamicin. Thus, the results from present study suggest that Spirulina platensis has renoprotective potential in gentamicin-induced acute tubular necrosis possibly due to its antioxidant properties.

Pineal gland has and antistressogenic role. Its main hormone, melatonin, has radio protective effect on endocrine and other dynamic tissues. In our previous study, we have shown that pinealectomy changes the behavior of suprarenal gland in totally irradiated rats. The aim of this study is to evaluate the effect of exogenous melatonin on suprarenal gland of rats with or without pineal gland. Four months after pinealectomy (experimental group) or shampinealectomy (control group), adult Wistar male rats were daily treated with 0,2 mg of melatonin intraperitoneally, during two weeks. Thereafter, all animals were totally irradiated with 8 Gy of Gamma rays produced from Cobalt 60. Animals who survived were sacrificed on the 17(th) post irradiation day. Qualitative and quantitative characteristics of the suprarenal gland were studied using histological methods. The results show that exogenous melatonin had protective role on suprarenal gland in totally irradiated rats and that those effects were more pronounced in the presence of pineal gland.

In the last few decades there has been a great development of regional anesthesia; all the postulates are defined and all the techniques of usage are perfected. However, like any other medical procedure, the block of brachial plexus carries a risk of certain unwanted complications, like possible intraneural and intravascular injections. The reason for great discrepancy between the injury of brachial plexus and other periphery nerves while performing the nerve blockade is the frequent usage of this block, but also the specific proximity of neurovascular structures in axilla. The purpose of this work is to determine the values of pressures which appear in para-neural, intraneural and intravascular injection applications of local anesthetic, and to compare those values in order to avoid cases of intraneural and intravascular injections in clinical practice with consequential complications. In experimental study there have been used 12 Wistar rats of both genders. After anesthesia with ether and mid-humoral access to the neurovascular structures in axilla, the injection of 2% lidocaine with epinephrine was performed with the help of automatic syringe charge. The needle was at first placed para-neural, and then also intraneural and intravascular. During every application the pressure values were monitored using the manometer, and then they were analyzed by special software program. All para-neural injections resulted with the pressure between 13,96-27,92 kPa. The majority of intraneural injections were combined with the injection pressure greater than 69,8 kPa, while the intravascular injections were combined with injection pressure less than 6,98 kPa. Based on the available data it can be noticed that so far none of the methods of prevention from unwanted complications of regional anesthesia can insure the avoidance of intraneural and intravascular injection of local anesthetic. Based on our research it is obvious that the measuring of pressure during the nerve blockade is very important in order to decrease the risk of neurological and possible systematic complications. It is also clear that a small, mobile, and financially quite available apparatus for pressure measurement can help in differentiation between para-neural, intraneural and intravascular injection. Avoiding high injection pressure prevents from lodging the needle into intraneural space, while avoiding a very low injection pressure prevents from lodging the needle into intravascular space followed by consequential complications. The usage of this apparatus can find its application in other blockades of periphery nerves, and in other branches of medicine as well.