Hydroxyapatite Crystal Thickness and Buckling Phenomenon in Bone Nanostructure During Mechanical Tests.

An investigation of bone samples taken from the left ulna of New Zealand white rabbits, with and without stresses and hysteresis loop, was undertaken using Small Angle X-ray Scattering technique. The purpose of this study is to investigate the nanostructural changes in the mean size of hydroxyapatite crystals thickness (T) during different mechanical conditions. The experiments were performed using bone samples aged 2 and 4 weeks, with and without strontium ranelate treatment, after compressive load and hysteresis loop. We did not observe any clear effects of strontium ranelate on the bones since the MANOVA test for epiphysis and diaphysis were found. On the other hand, a significant difference appears in epiphysis between 2 and 4 weeks. Furthermore, a reduction in the mean size of hydroxyapatite crystal thickness was observed when the loading pressure force increased, due to the buckling phenomenon. A return of memory points in the elastic region of the bone was observed. The significance of these results lays on the development of nanoproducts, with properties that are closer to the actual bone structure.

Potentially probiotic Lactobacillus strains with anti-proliferative activity induce cytokine/chemokine production and neutrophil recruitment in mice.

Lactobacillus pentosus B281 and Lactobacillus plantarum B282 are two Lactobacillus strains previously isolated from fermented table olives. Both strains were found to possess probiotic properties and displayed desirable technological characteristics for application as starters in novel functional food production. In the present study the anti-proliferative and immunostimulatory activities of the two strains were investigated. Firstly, we demonstrated that live L. pentosus B281 and L. plantarum B282 significantly inhibited the growth of human colon cancer cells (Caco-2) in a time- and dose-dependent manner. By employing the air pouch system in mice, we showed that administration of both strains led to a rapid and statistically significant infiltration of leukocytes in the air pouch exudates. The phenotypical characterisation of the recruited immune cells was performed by flow cytometry analysis. We demonstrated that the majority of the infiltrated leukocytes were neutrophils. Finally by using the Mouse Cytokine Array Panel A Detection Antibody cocktail, we showed that both strains induced the expression of granulocyte-colony stimulating factor, interleukin (IL)-1α, IL-1ß, IL-6, chemokine (C-X-C motif) ligand (CXCL)-1, chemokine (C-C motif) ligand (CCL)-3, CCL-4, and CXCL-2 and diminished the expression levels of soluble intercellular adhesion molecule, macrophage colony-stimulating factor and metallopeptidase inhibitor 1. Our results showed that both strains display anti-proliferative and immunostimulatory properties equal or even better in some cases than those of established and commonly used probiotic strains. These findings further support the probiotic character of the two strains.

Liver radiofrequency ablation compromises the biological gut barrier.

AIM: Liver radiofrequency ablation (RFA) has been shown to disrupt the mechanical component of the gut barrier. The aim of the present study was to investigate the consequences of liver RFA on the biological gut barrier in terms of the effects of bile production rate and bowel inflammatory state on intestinal microflora balance. METHOD: A total of 25 New Zealand rabbits were assigned to five groups (n = 5 per group): group CBD: subjected to common bile duct (CBD) extracorporeal bypass; group CBD-RFA: subjected to CBD bypass plus one session of open liver RFA; group RFA: subjected to liver RFA; group sham: subjected to sham operation; and group TBD: subjected to total bile deviation (TBD). In groups CBD and CBD-RFA, bile production rate was assessed for 48 h. In groups sham and RFA, measurement of biliary glycine conjugates of cholic and deoxycholic acid levels, histopathologic examination of the non-ablated liver tissue, morphometric analysis, and histopathologic examination of the terminal ileum and microbiological analysis of fecal and tissue samples collected from the jejunum and the cecum (and in group TBD) were performed at 48 h post-operation. RESULTS: One session of liver RFA resulted in ablation of 18.7 ± 2.7% of liver weight. Following liver RFA, bile production rate was reduced, while the levels of biliary bile salts were not affected. There was mild injury of the non-ablated liver parenchyma, mild intestinal wall inflammation, intestinal mucosa atrophy, and intestinal microbial population overgrowth. CONCLUSION: Reduced in bile production and mild bowel inflammation secondary to liver RFA impaired the biological gut barrier as manifested by intestinal microflora imbalance.

Immunohistochemical studies of wound healing after monopolar electrocautery and ultrasound submucosal inferior nasal turbinate reduction in sheep.

BACKGROUND: Extracellular matrix (ECM) proteins such as fibronectin and collagen III, enzymes such as matrix metalloproteinases and macrophages have been demonstrated to intervene in nasal and paranasal sinuses wound healing. AIM OF THE STUDY: To compare concentration of ECM proteins, enzymes and the recruitment of macrophages during wound repair after monopolar electrocautery in contrast with ultrasound submucosal surgical tissue reduction of inferior nasal turbinate (INT) tested in sheep. MATERIALS AND METHODS: Prospective controlled study in sheep. Immunostaining for collagen III, fibronectin, CD68 and matrix metalloproteinase-9 (MMP9) was applied in tissue specimens of INT mucosa after monopolar electrocoagulation (MEC) and ultrasound tissue reduction (UTR). Twelve INTs were studied 1, 3 and 8 weeks post-operatively in each interventional group (MEC and UTR) and 5 INTs were studied in animals of the control group (without surgery). The immunoreactivity was quantitatively graded between 0% to 100% immunoreactivity by a blinded senior pathologist. RESULTS: At the end of the study period collagen III, fibronectin and MMP9 were increased in both groups compared to the levels of the control group. When compared to control group, CD68 immunoreactivity was found higher in MEC group but not in UTR group. Fibronectin subepithelial immunoreactivity exhibited a substantial negative correlation with mucosal epithelial cell necrosis, a substantial positive correlation with fibrosis in MEC-treated specimens and a significant positive correlation with sinusoid engorgement in UTR-treated specimens. Collagen III tissue immunoreactivity showed a particularly significant negative correlation with sinusoid engorgement in MEC-treated specimens. CONCLUSION: Correlation of fibronectin and collagen III immunoreactivity to histopathologic findings suggests different ECM repair processes between MEC and UTR turbinate tissue reduction. The use of CD68 and MMP9 provides additional clues to the mode of actions of these techniques and to the molecular and cellular events of the nasal mucosa wound healing process.

Evaluation of the oscillometric technique for intermittent non-invasive arterial blood pressure measurement in the anaesthetized pig.

This study was designed to evaluate the oscillometric technique for intermittent non-invasive measurement of arterial pressure (AP) in the anaesthetized pig. In six pigs under sevoflurane anaesthesia, intermittent (every 2 minutes) oscillometric measurements of AP made at a forelimb (FL), a hindlimb (HL) and the tail base were compared with simultaneous direct AP measurements made at the aortic arch (AA) over a wide pressure range (30-140 mmHg of mean AP). All oscillometric measurements strongly correlated (Pearson correlation coefficient >0.837, P < 0.001) with direct AP measurements, with those made at the FL exhibiting the highest correlation. On the basis of consistency of difference between oscillometric and AA pressure readings at graded pressure levels, measurements made at the tail base provided reliable prediction of systolic AP, at the FL of diastolic AP and at both the tail base and the FL of mean AP. In conclusion, oscillometric measurements at the FL and the tail base offer reliable prediction of AP in the anaesthetized pig.

A case of diffuse bilateral scrotal neurofibroma in a rabbit.

This report details a rare case of diffuse bilateral scrotal neurofibroma complicated by hindlimb paralysis in a rabbit. The animal was evaluated for unusual bilateral scrotal enlargement. After physical examination, ultrasound scan, radiography, computed tomography and laparoscopy, surgical exploration of the scrotum was undertaken. A homogeneous rubbery firm mass was revealed in contact with the subcutaneous tissue expanding to the entire scrotum without involving the testicles. The mass was excised and diagnosed as diffuse scrotal neurofibroma based on histological and immunohistochemical findings (S-100 antibody positive). Over the following month, progressive neurological signs (faecal incontinence, flaccid bladder and hindlimb paralysis) were observed. After excluding central nervous system infection with Encephalitozoon cuniculi, expansion of the neurofibroma to the vertebral canal causing compression of the spinal cord was suspected, although not histopathologically verified.

Evaluation of the LIM homeobox genes LHX6 and LHX8 as candidates for Tourette syndrome.

The etiology and pathophysiology of Tourette Syndrome (TS) remain poorly understood. Multiple lines of evidence suggest that a complex genetic background and the cortico-striato-thalamo-cortical circuit are involved. The role of Lhx6 and Lhx8 in the development of the striatal interneurons, prompted us to investigate them as novel candidate genes for TS. We performed a comparative study of the expression of Lhx6 and Lhx8 and investigated genetic association with TS using two samples of trios (TSGeneSEE and German sample - 222 families). We show that Lhx6 and Lhx8 expression in the forebrain is evolutionarily conserved, underlining their possible importance in TS-related pathophysiological pathways. Our tagging-single nucleotide polymorphism (tSNP)-based association analysis was negative for association with LHX8. However, we found positive association with LHX6 in the TSGeneSEE sample (corrected P-value = 0.006 for three-site haplotype around SNP rs3808901) but no association in the sample of German families. Interestingly, the SNP allele that was identified to be significantly associated in the TSGeneSEE dataset, showed an opposite trend of transmission in the German dataset. Our analysis of the correlation of the LHX6 region with individual ancestry within Europe, revealed the fact that this particular SNP demonstrates a high degree of population differentiation and is correlated with the North to South axis of European genetic variation. Our results indicate that further study of the LHX6 gene in relation to the TS phenotype is warranted and suggest the intriguing hypothesis that different genetic factors may contribute to the etiology of TS in different populations, even within Europe.

A comparative study of invasive and oscillometric methods of arterial blood pressure measurement in the anesthetized rabbit.

INTRODUCTION: The aim of this project was to evaluate the reliability and accuracy of direct, using the central ear artery (CEA), and oscillometric, using limb-cuffs, methods of arterial blood pressure (AP) measurement in the anesthetized rabbit. METHODS: New Zealand rabbits were anesthetized using a xylazine-ketamine-isoflurane protocol. Using the abdominal aorta (ABA) as direct "gold standard" for AP measurements, ABA pressure readings, via femoral artery catheterization, were compared with those made simultaneously from the ascending aorta after median sternotomy. Thereafter, direct CEA as well as forelimb-(FL) and hindlimb-(HL) cuff oscillometric readings were compared with those made simultaneously from ABA. RESULTS: The blood pressure in the ABA correlated with that from ascending aorta. Furthermore, CEA correlated with the ABA readings. Nevertheless, at high pressures, their divergence from "true" pressure tended to increase. Oscillometric readings at the FL site correlated well with "true" pressure while those at the HL site did not. Their divergence tended to increase at high pressures when using the FL site, while it varied when using the HL site. The accuracy of measurements was moderate for the FL site while poor for the HL site. DISCUSSION: Our results suggest that the CEA can be readily used with high reliability and accuracy for direct AP measurements in the anesthetized rabbit. On the other hand, the FL-cuff oscillometric method should only be used for the evaluation of AP at low and normal pressure ranges.

Penetration of newer quinolones in the empyema fluid.

The degree of penetration of newer quinolones into the pleural fluid has not been studied. The objective of the present study was to determine the degree to which moxifloxacin and levofloxacin penetrate into empyemic pleural fluid using a new rabbit model of empyema. An empyema was created via the intrapleural injection of turpentine (1 mL), followed 24 h later by instillation of 2 mL (1 x 10(10)) Escherichia coli bacteria (ATCC 35218) into the pleural space of New Zealand white rabbits. After an empyema was verified by thoracentesis and pleural fluid analysis, moxifloxacin and levofloxacin (25 mg.kg(-1) for both, i.v.) were administered. Antibiotic levels were determined in samples of pleural fluid and in blood collected serially over 12 h. Antibiotic levels were measured using HPLC. Each of the antibiotics penetrated well into the empyemic pleural fluid. Antibiotic penetration was the greatest for moxifloxacin (area under the curve (AUC) for pleural fluid/blood (AUCPF/AUCblood) ratio=1.37) followed by levofloxacin (ratio=1.13). The time to equilibration between the pleural fluid and blood antibiotic levels was more rapid for moxifloxacin (3.9 h) than for levofloxacin (4.4 h). With moxifloxacin, the peak pleural fluid concentration (Cmax,PF) was 2.77 microg.mL(-1) and occurred at a time to maximum pleural fluid concentration (Tmax,PF) of 6 h after infusion and decreased thereafter. The peak blood concentration (Cmax,blood) was 4.81 microg.mL(-1) at 1 h after administration. With levofloxacin, the peak pleural fluid level (Cmax,PF=1.39 microg.mL(-1)) occurred at 6 h (Tmax,PF=6 h) after infusion. The Cmax,blood was 1.88 microg.mL(-1) at 1 h after administration. In conclusion, differences were found in the degree of penetration of the two quinolones into infected pleural fluid in rabbits. The clinical significance of these differences is unknown. More studies are needed to evaluate the pharmacokinetic parameters in the pleural space in humans.

Semen quality during vincristine treatment in dogs with transmissible venereal tumor.

The aim of this study was to evaluate the direct effects of vincristine on semen quality in dogs with transmissible venereal tumor (TVT). We examined the semen of 17 dogs suffering from TVT during vincristine treatment. Each animal received 0.6 mg, i.v. vincristine sulphate per square meter of body surface, per week for 4 wk until complete regression of the tumor. The following semen parameters were evaluated: semen volume (second fraction), sperm concentration, total spermatozoa per ejaculate, percentage of progressively motile spermatozoa, percentage of dead spermatozoa, percentage of swollen spermatozoa (hypo-osmotic swelling test) and percentage of morphologically abnormal spermatozoa (primary and secondary defects). Semen was collected and evaluated prior to the beginning of treatment, 3 d after each vincristine injection and 15 d after the last injection. Semen characteristics transiently deteriorated during treatment, but returned to normal 15 d later. These changes were attributed to a direct effect of vincristine on the extragonadal spermatozoal reserves contained in the epididymis and ductus deferens. A GnRH stimulation test was also performed after each semen collection in order to assess the function of the hypothalamic-pituitary-Leydig cell axis. No effect was noted on the above axis.