Plasma levels of chemokines CCL2 and CXCL12 in female dogs with malignant mammary gland tumours without and with metastases

The aim of this study was to evaluate the plasma levels of chemokines CCL2 and CXCL12 in female dogs with malignant mammary gland tumours without and with metastases. The concentrations of CCL2 and CXCL12 were determined in 25 female dogs with malignant mammary gland tumours (15 without metastases and 10 with metastases) and 10 healthy control animals using a specific canine ELISA assay. The mean plasma concentrations of CCL2 and CXCL12 were significantly higher (p<0.05) in the metastatic group compared to the control group. Moreover, the concentrations of these chemokines were markedly higher in the dogs with metastases than in those without metastases; however, a statistically significant difference was not found. The concentrations of both tested chemokines were numerically increased in the dogs with grade 2 and grade 3 carcinomas compared to the dogs with grade 1 carcinomas but the differences did not reach statistical significance. In conclusion, the results of our study demonstrate that plasma concentrations of chemokines CCL2 and CXCL12 are significantly increased in the dogs with metastatic malignant mammary gland tumours compared to the healthy dogs and show an upward trend compared to those without metastases. However, clarifying whether the increase of these chemokines is a cause or an effect of metastasis in female dogs with malignant mammary gland tumours as well as their potential role in metastatic process requires further research.

Plasma interleukin-1α and interleukin-8 in female dogs with non-metastatic and metastatic malignant mammary gland tumours

In this study plasma concentrations of IL-1α and IL-8 in 29 female dogs with malignant mammary gland tumours (19 without metastasis and 10 with metastasis) and in 10 healthy control animals were determined. Concentrations of IL-1α and IL-8 were analysed using a specific canine ELISA assay. Mean plasma concentrations of IL-1α and IL-8 were significantly higher (p⟨0.05) in female dogs with both non-metastatic and metastatic malignant tumours compared to the healthy animals. The concentrations of both tested cytokines were significantly increased (p⟨0.05) in the dogs with metastasis. In female dogs with mammary carcinomas, the plasma concentration of IL-1α was significantly higher (p⟨0.05) in the animals with grade 3 tumours compared to the dogs with grade 1 tumours. The concentration of IL-8 was significantly higher (p⟨0.05) in the dogs with grade 3 tumours compared to that found in the animals with grade 1 and grade 2 tumours. A moderate correlation (r=0.433) was found between IL-1α and IL-8 concentrations in the female dogs. These findings suggest that increased malignancy and invasiveness of canine mammary tumours is associated with an increased production of IL-1α and IL-8 in the tumour microenvironment, which, in turn, leads to an increase in their circulating levels. This may indicate that circulating levels of the cytokines investigated could be considered as diagnostic and prognostic markers in canine malignant mammary tumours. However, further studies in this fields are needed.

Uterine non-enzymatic antioxidant defence mechanisms (glutathione, vitamin C, copper and zinc) in diagnosis of canine pyometra

The aim of the present study was to determine the concentrations of glutathione (GSH), vitamin C, copper (Cu) and zinc (Zn) in the uterine tissues in diagnosis of canine pyometra. Fourteen samples of uterine tissues from female dogs with pyometra and twelve samples of healthy uteruses (control) were used. The concentrations of GSH and vitamin C were determined in the uterine tissue homogenates using spectrophotometric methods. The concentrations of Cu and Zn were measured using atomic absorption spectrometer. The results obtained showed the significantly lower (p⟨0.05) concentration of GSH and the trend towards lower concentration of vitamin C in the pyometra samples compared to the control. The concentrations of Cu and Zn were similar in the uterine tissues from female dogs with pyometra and those from healthy female dogs. The lower GSH and vitamin C concentrations in the uterine tissues of female dogs with pyometra indicate that the non-enzymatic antioxidant mechanisms are impaired in the uterus of dogs with pyometra. These findings suggest that the imbalance of oxidative-antioxidative can play an important role in pathogenesis of canine pyometra.

Evaluation of adenosine deaminase in saliva and serum, and salivary α-amylase, in canine pyometra at diagnosis and after ovariohysterectomy

An assay for adenosine deaminase (ADA) was validated in serum and saliva in dogs. Changes in ADA and salivary α-amylase activities were analysed in 26 bitches diagnosed with pyometra and compared with activities in 19 healthy bitches. All animals were classified according to the American Society of Anaesthesiologists (ASA) scoring for physical status. In the validation study, the ADA assay had an imprecision<12% and determination coefficients>0.90 in linearity under dilution experiments, with recoveries of 99.2-114.4%. On the day of presentation, salivary ADA activity was significantly higher in dogs with pyometra than in healthy dogs (median values 7.1IU/L vs. 0.8IU/L, respectively; P<0.01). ADA had a moderate positive correlation with leucocyte and band neutrophil counts, haptoglobin, salivary α-amylase and ASA score, and a low positive correlation with C-reactive protein. There were no significant differences in salivary α-amylase activity between dogs with pyometra and healthy dogs (57.3IU/L vs. 27.4IU/L, respectively). Salivary α-amylase had a low correlation with ASA grade, and leucocyte and band neutrophil counts. In 7/26 bitches with pyometra that were sampled 3 and 10days after ovariohysterectomy, there were no significant changes in α-amylase or ADA activities. These results indicate that ADA activity is increased in the saliva of bitches with pyometra, probably related to systemic inflammation.

Factors responsible for subclinical mastitis in cows caused by Staphylococcus chromogenes and its susceptibility to antibiotics based on bap, fnbA, eno, mecA, tetK, and ermA genes

The aim of this study was to recognize selected factors of virulence determining the adhesion of Staphylococcus chromogenes to cows' udder tissues in subclinical mastitis and to evaluate the susceptibility of this pathogen to antibiotics. The subjects of the study were 38 isolates of Staph. chromogenes from 335 samples of milk from cows with subclinical coagulase-negative staphylococci mastitis. Somatic cell count ranged between 216,000 and 568,000/mL of milk (average 356,000/mL of milk). We confirmed the ability to produce slime in 24 isolates (63.2%), and the ability to produce protease in 29 isolates (76.3%). In each slime-producing isolate, the bap gene was not found, and the fnbA and eno genes were not detected. In vitro tests showed that ceftiofur had the highest effectiveness against Staph. chromogenes (89.5% of susceptible isolates). Minimum inhibitory concentrations ranged from 0.06 to 2µg/mL for susceptible isolates. The minimum concentrations required to inhibit growth of 90 and 50% of the isolates for ceftiofur were at or below the cutoffs recommended by the Clinical and Laboratory Standards Institute (2 and 0.06µg/mL, respectively). A significant percentage of the isolates were susceptible to other β-lactam antibiotics: amoxicillin with clavulanic acid (84.2%) and ampicillin (81.6%). The lowest effectiveness among β-lactams was for penicillin (73.7% of susceptible isolates), and the minimum inhibitory concentration for penicillin ranged from <0.06 to 8µg/mL. None of the examined isolates had the mecA gene, but β-lactamase was detected in 4 isolates (10.5%). Erythromycin and oxytetracycline exhibited the lowest activity against Staph. chromogenes (71.1 and 63.2% of susceptible isolates, respectively). The genes tetK (6 isolates) and ermA (1 isolate) were also detected.

Induction of a room temperature ferroelectric SmC* phase in binary mixtures with moderate spontaneous polarization and sub-millisecond switching time

Induction of room temperature SmC* phase in binary mixture.

Assessment of lipid and protein peroxidation markers in non-pregnant and pregnant female dogs

The aim of the study was to investigate oxidative stress during normal pregnancy in female dogs based on an evaluation of plasma markers for lipid and protein peroxidation. Twenty clinically healthy female dogs (10 non-pregnant and 10 pregnant) were used in the study. Blood samples from the pregnant animals were collected at 19-21, 38-40, and 56-58 days of pregnancy. Blood samples from non-pregnant female dogs were obtained between 20 and 35 days after ineffective breeding. As indicators of oxidative stress, we measured the following using spectrophotometric and spectrof- luorimetric methods: thiobarbituric acid reactive substances (TBARS), radical cations of N,N, diethylparaphenylene diamine (RC-DEPPD), sulfhydryl groups (SH groups), bityrosine and formylkynurenine. The mean plasma TBARS concentration in the pregnant dogs (0.486 ± 0.071-0.581 ± 0.191 μmol/g protein) was significantly higher (p < 0.05) than that found in the non-pregnant animals (0.274 ± 0.111 μmol/g protein). A marked, although not significant, decrease in SH group content, as well as an increase in bityrosine and formylkynurenine concentration were concurrently observed in the pregnant dogs. No significant differences were found in terms of the studied markers in the pregnant animals when comparing the values obtained during the investigated periods of pregnancy, although there was a progressive decrease in TBARS concentration and a progressive increase in RC-DEPPD, bityrosine and formylkynurenine contents. Our findings suggest that normal pregnancy in female dogs is associated with oxidative stress. Further studies are necessary to establish the physiological ranges of antioxidative/oxidative profiles in pregnant dogs and to explain if and how the intensity of oxidative stress might contribute to the risk of the complications of pregnancy.

Effects of ovariohysterectomy on oxidative stress markers in female dogs

Numerous studies reported an increase of oxidative stress increases in both women and female laboratory animals after ovariectomy. However, there is little information about the evaluation of antioxidative/oxidative status in ovariectomized dogs. The purpose of this study was to examine the changes in oxidative stress markers after ovariohysterectomy (OHE) in female dogs. The study included eighteen healthy mongrel female dogs. Blood samples were collected immediately before surgery and 14 and 30 days after surgery. Following parameters of oxidative stress intensity were determined: the erythrocyte activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) as well as the plasma concentrations of thiobarbituric acid reactive substances (TBARS), radical cations of N,N, diethylpara-phenylene diamine (RC-DEPPD), sulfhydryl groups (SH groups), bityrosine and formylkynurenine. The activity of GSH-Px increased markedly, although not significantly, 14 days after OHE and then significantly decreased at 30 days after OHE. A significant increase in plasma TBARS, bityrosine and formylkynurenine concentrations and a decrease in SH group content were concurrently noted at 30 days after surgery. Acquired results suggested that a loss of control over ROS production occurred in female dogs after OHE, which could lead to oxidative stress in the late post-operative period. In conclusion, our findings indicated that OHE is related with the risk of oxidative stress in the late period after operations. Given that oxidative stress contributes to the pathogenesis of various diseases, this may suggest an increased risk of disorders in ovariectomized female dogs; however, further studies are necessary to confirm this hypothesis.

Dielectric Relaxation Studies of 4-n-Alkyloxy-4’-Cyanobiphenyls (nOCB, n= 5÷8)

The results of dielectric relaxation studies of series of four n-alkyloxy cyanobiphenyl (nOCB) compounds with n ranging from 5 to 8 are presented. The complex dielectric permittivity, ε*(ω) - ε’(ω) - i ε’’(ω), was measured in the frequency range 1 kHz - 3 GHz, with the use of an impedance analyzer and a time domain spectroscopy (TDS) set-up. The relaxation times: longitudinal τ|| in the nematic and smectic A phase (80CB), transverse τ⊥ in the nematic phase, and τis in the isotropic phase, were obtained as functions of the temperature. This allowed the calculation of activation barriers for different molecular relaxation processes occurring in particular phases. More-over, the retardation factors g|| and g⊥ and the nematic potential q according to two theoretical models were calculated. The analysis of q(T) and its relation to the order parameter S is done taking into account the results of NMR studies of the compounds under consideration. Finally, the dependencies of the obtained quantities on the number of carbon atoms in the alkyloxy chains are analyzed.

Serum neopterin levels in female dogs with malignant mammary tumours

In this study, we have determined serum neopterin levels in female dogs with primary malignant mammary tumours. The study involved 50 female dogs which had a malignant mammary tumours removed surgically (32 animals with carcinoma, 12 animals with sarcoma and 6 animals with carcinosarcoma) and 10 clinically healthy female dogs. Serum neopterin levels were determined using a commercial ELISA kit. The mean neopterin levels were lower in the malignant tumour groups than in healthy animals but differences were statistically significant only in carcinoma and sarcoma groups. The decrease of neopterin levels in animals with malignant mammary tumours may suggest their decreased cellular immunity. Moreover, it might indicate that decreased activity of cellular mechanisms of the anti-neoplastic response is one of the factors associated with the development and course of malignant mammary tumours in female dogs; however, further studies are necessary.

The Physical and Molecular Properties of New Low Melting Nematics with Negative Dielectric Anisotropy

The paper presents some basic physical properties (static electric permittivities, refraction indices, density and viscosity) of 2-chloro-4-n’-alkylphenyl esters of 4-n-alkylbicyclo[2,2,2] octane-1-carboxylic acids (n’=7, n = 5 and 7) which are, at room temperature, nematics with a negative dielectric an-isotropy. On the basis of temperature dependence of the principal static permittivities ε‖(T) and e⊥(T) of the nematics, using the Maier-Meier equations, the angle between the dipole moment vector and the long axis of mesogenic molecules, the apparent molecular dipole moment square pl μ2app(T), and the nematic order parameter S(T) were determined.