scholarly journals The Electricidal Effect Is Active in an Experimental Model of Staphylococcus epidermidis Chronic Foreign Body Osteomyelitis

2009 ◽  
Vol 53 (10) ◽  
pp. 4064-4068 ◽  
Author(s):  
Jose L. Del Pozo ◽  
Mark S. Rouse ◽  
Gorane Euba ◽  
Cheol-In Kang ◽  
Jayawant N. Mandrekar ◽  
...  
Keyword(s):  
Foreign Body ◽  
Staphylococcus Epidermidis ◽  
Bacterial Load ◽  
Rabbit Model ◽  
Electrical Current ◽  
Bacterial Biofilms ◽  
Control Group ◽  
Doxycycline Treatment ◽  
Continuous Delivery

ABSTRACT Treatment with low-amperage (200 μA) electrical current was compared to intravenous doxycycline treatment or no treatment in a rabbit model of Staphylococcus epidermidis chronic foreign body osteomyelitis to determine if the electricidal effect is active in vivo. A stainless steel implant and 104 CFU of planktonic S. epidermidis were placed into the medullary cavity of the tibia. Four weeks later, rabbits were assigned to one of three groups with treatment administered for 21 days. The groups included those receiving no treatment (n = 10), intravenous doxycycline (n = 14; 8 mg/kg of body weight three times per day), and electrical current (n = 15; 200 μA continuous delivery). Following treatment, rabbits were sacrificed and the tibias quantitatively cultured. Bacterial load was significantly reduced in the doxycycline (median, 2.55 [range, 0.50 to 6.13] log10 CFU/g of bone) and electrical-current (median, 1.09 [range, 0.50 to 2.99] log10 CFU/g of bone) groups, compared to the level for the control group (median, 4.16 [range, 3.70 to 5.66] log10 CFU/g of bone) (P < 0.0001). Moreover, treatment with electrical current was statistically significantly more efficacious (P = 0.035) than doxycycline treatment. The electricidal effect (the bactericidal activity of low-amperage electrical current against bacterial biofilms) is active in vivo in the treatment of experimental S. epidermidis chronic foreign body osteomyelitis.

scholarly journals Effect of Acute Increases in Intraocular Pressure on Corneal Pachymetry in Rabbit Eyes Treated with Timolol Maleate

2018 ◽  
Vol 12 (1) ◽  
pp. 314-321
Author(s):  
Cristina Sánchez-Barahona ◽  
Gema Bolívar ◽  
Dimitrios G. Mikropoulos ◽  
Anastasios G. Konstas ◽  
Miguel A. Teus
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Rabbit Model ◽  
Controlled Study ◽  
Control Group ◽  
Study Group ◽  
Timolol Maleate

Objective: To evaluate in an in vivo rabbit model, the effect of topical timolol maleate therapy on the central corneal thickness response to acute intraocular pressure increases. Method: In this prospective and interventional controlled study, the central corneal thickness and intraocular pressure were measured in vivo in 12 rabbit eyes treated with topical timolol maleate for 1 month and in 12 controls at baseline, and after the intraocular pressure (measured by direct cannulation of the anterior chamber) was increased to 15 and 30 mmHg using a forced saline infusion into the anterior chamber. Results: There were no significant differences in the basal central corneal thickness values (control group, 373.2±12.9 µm; study group, 377.5±19.2 µm, p=0.5) or the central corneal thickness values when the intraocular pressure was increased to 15 mmHg (control group, 335.2±14.3 µm; study group, 330.0±32.1 µm, p=0.6) and to 30 mmHg (study group, 318.8±25.3 µm; control group, 329.8±21.0 µm, p=0.3). Conclusion: Rabbit corneas treated with topical timolol maleate for 1 month did not show a strain response to acute intraocular pressure increases that differed from control eyes. This is in contrast to a previous finding in which rabbit eyes treated with prostaglandin analogues had a greater decrease in central corneal thickness in response to a sudden intraocular pressure increase compared with untreated corneas.

scholarly journals Treatment with Linezolid or Vancomycin in Combination with Rifampin Is Effective in an Animal Model of Methicillin-ResistantStaphylococcus aureusForeign Body Osteomyelitis

2010 ◽  
Vol 55 (3) ◽  
pp. 1182-1186 ◽  
Author(s):  
Paschalis Vergidis ◽  
Mark S. Rouse ◽  
Gorane Euba ◽  
Melissa J. Karau ◽  
Suzannah M. Schmidt ◽  
...  
Keyword(s):  
Animal Model ◽  
Foreign Body ◽  
Proximal Tibia ◽  
Bacterial Load ◽  
Control Group ◽  
Treatment Groups ◽  
Titanium Wire ◽  
Experimental Rat Model ◽  
Rifampin Resistance ◽  
All Treatment

ABSTRACTRifampin monotherapy was compared to the combination of linezolid or vancomycin with rifampin in an experimental rat model of methicillin-resistantStaphylococcus aureus(MRSA) chronic foreign body osteomyelitis. MRSA was inoculated into the proximal tibia, and a titanium wire was implanted. Four weeks after infection, rats were treated intraperitoneally for 21 days with rifampin alone (n= 16), linezolid plus rifampin (n= 14), or vancomycin plus rifampin (n= 13). Thirteen animals received no treatment. At completion of treatment, qualitative cultures of the wire and quantitative cultures of the bone (reported as median values) were performed. Quantitative cultures from the control, rifampin monotherapy, linezolid-plus-rifampin, and vancomycin-plus-rifampin groups revealed 4.54, 0.71, 0.10, and 0.50 log10CFU/gram of bone, respectively. The bacterial load was significantly reduced in all treatment groups compared to that in the control group. Rifampin resistance was detected in isolates from 10, 2, and 1 animal in the rifampin, linezolid-plus-rifampin, and vancomycin-plus-rifampin groups, respectively. Cultures of the removed wire revealed bacterial growth in 1 and 2 animals in the rifampin and linezolid-plus-rifampin groups, respectively, with no growth in the vancomycin-plus-rifampin group and growth from all wires in the untreated group. In conclusion, we demonstrated that combination treatment with linezolid plus rifampin or vancomycin plus rifampin is effective in an animal model of MRSA foreign body osteomyelitis in the context of retention of the infected foreign body.

scholarly journals Comparative Effects of Verapamil, Nicardipine, and Nitroglycerin on Myocardial Ischemia/Reperfusion Injury

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Hitoshi Yui ◽  
Uno Imaizumi ◽  
Hisashi Beppu ◽  
Mitsuhiro Ito ◽  
Munetaka Furuya ◽  
...  
Keyword(s):  
Infarct Size ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Rabbit Model ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Control Group ◽  
Area At Risk ◽  
Group A

The aim of this experiment was to establish whether verapamil, nicardipine, and nitroglycerin have (1) infarct size-limiting effects and (2) antiarrhythmic effects inin vivorabbit hearts during ischemia/reperfusion. Rabbits received regional ischemia by 30 min of left anterior descending coronary artery occlusion followed by 3 hours of reperfusion under ketamine and xylazine anesthesia. The animals were randomly assigned to the following 4 treatment groups: a control group, a verapamil group, a nicardipine group, and a nitroglycerin group. A continuous infusion of verapamil, nicardipine, or nitroglycerin was initiated 5 min prior to ischemia. Infarct size/area at risk decreased in verapamil, and nitroglycerin. The incidence of ischemia-induced arrhythmia decreased in nicardipine, verapamil and nitroglycerin. The incidence of reperfusion-induced arrhythmias decreased in verapamil and nitroglycerin. From the present experimental results, verapamil and nitroglycerin rather than nicardipine did afford significant protection to the heart subjected to ischemia and reperfusion in a rabbit model.

scholarly journals Enhancement of Vancomycin Activity against Biofilms by Using Ultrasound-Targeted Microbubble Destruction

2011 ◽  
Vol 55 (11) ◽  
pp. 5331-5337 ◽  
Author(s):  
Nianan He ◽  
Jian Hu ◽  
Huayong Liu ◽  
Tao Zhu ◽  
Beijian Huang ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Laser Scanning ◽  
Rabbit Model ◽  
Antibiotic Activity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Content Type ◽  
Implanted Medical Devices

ABSTRACTTreating biofilm infections on implanted medical devices is formidable, even with extensive antibiotic therapy. The aim of this study was to investigate whether ultrasound (US)-targeted microbubble (MB) destruction (UTMD) could enhance vancomycin activity againstStaphylococcus epidermidisRP62A biofilms. Twelve-hour biofilms were treated with vancomycin combined with UTMD. The vancomycin and MB (SonoVue) were used at concentrations of 100 μg/ml and 30% (vol/vol), respectively, in studiesin vitro. After US exposure (0.08 MHz, 1.0 W/cm2, 50% duty cycle, and 10-min duration), the biofilms were cultured at 37°C for another 12 h. The results showed that many micropores were found in biofilms treated with vancomycin combined with UTMD. Biofilm densities (A570values) and the viable counts ofS. epidermidisrecovered from the biofilm were significantly decreased compared with those of any other groups. Furthermore, the highest percentage of dead cells was found, using confocal laser scanning microscopy, in the biofilm treated with vancomycin combined with UTMD. The viable counts of bacteria in biofilms in anin vivorabbit model also confirmed the enhanced effect of vancomycin combined with UTMD. UTMD may have great potential for improving antibiotic activity against biofilm infections.

scholarly journals A Complex Evaluation of the In-Vivo Biocompatibility and Degradation of an Extruded ZnMgSr Absorbable Alloy Implanted into Rabbit Bones for 360 Days

2021 ◽  
Vol 22 (24) ◽  
pp. 13444
Author(s):  
Karel Klíma ◽  
Dan Ulmann ◽  
Martin Bartoš ◽  
Michal Španko ◽  
Jaroslava Dušková ◽  
...  
Keyword(s):  
Bone Fractures ◽  
Rabbit Model ◽  
Control Group ◽  
Metallic Materials ◽  
Second Stage ◽  
Complex Evaluation ◽  
Rabbit Tibia ◽  
Good Biocompatibility ◽  
Materials Used

The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure—the removal of the plates and screws—can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.

scholarly journals A novel in vivo method for quantifying the interfacial biochemical bond strength of bone implants

2009 ◽  
Vol 7 (42) ◽  
pp. 81-90 ◽  
Author(s):  
Young-Taeg Sul ◽  
Carina Johansson ◽  
Tomas Albrektsson
Keyword(s):  
Bond Strength ◽  
Close Contact ◽  
Rabbit Model ◽  
Test Group ◽  
Titanium Implants ◽  
Control Group ◽  
Bone Implants ◽  
Oxygen Control ◽  
Interfacial Bond Strength

Quantifying the in vivo interfacial biochemical bond strength of bone implants is a biological challenge. We have developed a new and novel in vivo method to identify an interfacial biochemical bond in bone implants and to measure its bonding strength. This method, named biochemical bond measurement (BBM), involves a combination of the implant devices to measure true interfacial bond strength and surface property controls, and thus enables the contributions of mechanical interlocking and biochemical bonding to be distinguished from the measured strength values. We applied the BBM method to a rabbit model, and observed great differences in bone integration between the oxygen (control group) and magnesium (test group) plasma immersion ion-implanted titanium implants (0.046 versus 0.086 MPa, n =10, p =0.005). The biochemical bond in the test implants resulted in superior interfacial behaviour of the implants to bone: (i) close contact to approximately 2 μm thin amorphous interfacial tissue, (ii) pronounced mineralization of the interfacial tissue, (iii) rapid bone healing in contact, and (iv) strong integration to bone. The BBM method can be applied to in vivo experimental models not only to validate the presence of a biochemical bond at the bone–implant interface but also to measure the relative quantity of biochemical bond strength. The present study may provide new avenues for better understanding the role of a biochemical bond involved in the integration of bone implants.

scholarly journals Effects of Dantrolene on Arrhythmogenicity in Isolated Regional Ischemia-Reperfusion Rabbit Hearts with or without Pacing-Induced Heart Failure

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Chung-Chuan Chou ◽  
Hui-Ling Lee ◽  
Po-Cheng Chang ◽  
Hung-Ta Wo ◽  
Ming-Shien Wen ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ischemia Reperfusion ◽  
Rabbit Model ◽  
Control Group ◽  
Ventricular Premature Beat ◽  
Coronary Artery Ligation ◽  
Artery Ligation ◽  
Regional Ischemia ◽  
Intracellular Ca

Dantrolene was reported to suppress ventricular fibrillation (VF) in failing hearts with acute myocardial infarction, but its antiarrhythmic efficacy in regional ischemia-reperfusion (IR) hearts remains debatable. Heart failure (HF) was induced by right ventricular pacing. The IR rabbit model was created by coronary artery ligation for 30 min, followed by reperfusion for 15 min in vivo in both HF and non-HF groups (n= 9 in each group). Simultaneous voltage and intracellular Ca2+(Cai) optical mapping was then performed in isolated Langendorff-perfused hearts. Electrophysiological studies were conducted and VF inducibility was evaluated by dynamic pacing. Dantrolene (10 μM) was administered after baseline studies. The HF group had a higher VF inducibility than the control group. Dantrolene had both antiarrhythmic (prolonged action potential duration (APD) and effective refractory period) and proarrhythmic effects (slowed conduction velocity, steepened APD restitution slope, and enhanced arrhythmogenic alternans induction) but had no significant effects on ventricular premature beat (VPB) suppression and VF inducibility in both groups. A higher VF conversion rate in the non-HF group was likely due to greater APD prolonging effects in smaller hearts compared to the HF group. The lack of significant effects on VPB suppression by dantrolene suggests that triggered activity might not be the dominant mechanism responsible for VPB induction in the IR model.

Evaluation of emphysema severity and progression in a rabbit model: comparison of hyperpolarized 3He and 129Xe diffusion MRI with lung morphometry

2007 ◽  
Vol 102 (3) ◽  
pp. 1273-1280 ◽  
Author(s):  
Jaime F. Mata ◽  
Talissa A. Altes ◽  
Jing Cai ◽  
Kai Ruppert ◽  
Wayne Mitzner ◽  
...  
Keyword(s):  
Model Comparison ◽  
Structural Changes ◽  
Rabbit Model ◽  
B Value ◽  
Saline Control ◽  
Control Group ◽  
B Values ◽  
Apparent Diffusion Coefficients ◽  
Change In Mean

The apparent diffusion coefficients (ADCs) of hyperpolarized 3He and 129Xe gases were measured in the lungs of rabbits with elastase-induced emphysema and correlated against the mean chord length from lung histology. In vivo measurements were performed at baseline and 2, 4, 6, and 8 wk after instillation of elastase (mild and moderate emphysema groups) or saline (control group). ADCs were determined from acquisitions that used two b values. To investigate the effect of b value on the results, b-value pairs of 0 and 1.6 s/cm2 and 0 and 4.0 s/cm2 were used for 3He, and b-value pairs of 0 and 5.0 s/cm2 and 0 and 10.0 s/cm2 were used for 129Xe. At 8 wk after instillation, the rabbits were euthanized, and the lungs were analyzed histologically and morphometrically. ADCs for the rabbits in the control group did not change significantly from baseline to week 8, whereas ADCs for the rabbits in the emphysema groups increased significantly ( P < 0.05) for all gas and b-value combinations except 129Xe with the b-value pair of 0 and 5.0 s/cm2. The largest percent change in mean ADC from baseline to week 8 (15.3%) occurred with 3He and the b-value pair of 0 and 1.6 s/cm2 for rabbits in the moderate emphysema group. ADCs (all b values) were strongly correlated ( r = 0.62–0.80, P < 0.001) with mean chord lengths from histology. These results further support the ability of diffusion-weighted MRI with hyperpolarized gases to detect regional and global structural changes of emphysema within the lung.

scholarly journals In Vitro and In Vivo Efficacies of Teicoplanin-Loaded Calcium Sulfate for Treatment of Chronic Methicillin-Resistant Staphylococcus aureus Osteomyelitis

2009 ◽  
Vol 54 (1) ◽  
pp. 170-176 ◽  
Author(s):  
Wei-Tao Jia ◽  
Shi-Hua Luo ◽  
Chang-Qing Zhang ◽  
Jian-Qiang Wang
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Calcium Sulfate ◽  
Release Kinetics ◽  
Bacterial Load ◽  
Rabbit Model ◽  
Methicillin Resistant ◽  
Group 2

ABSTRACT The i n vitro and in vivo therapeutic efficacies of teicoplanin-loaded calcium sulfate (TCS; 10% [wt] teicoplanin) were investigated in a rabbit model of chronic methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis. The in vitro elution characteristics of teicoplanin from TCS pellets were realized by carrying out an evaluation of the release kinetics, recovery rate, and antibacterial activity of the released teicoplanin. Chronic osteomyelitis was induced by inoculating 107 CFU of a MRSA strain into the tibial cavity of rabbits. After 3 weeks, the animals were treated by debridement followed by implantation of TCS pellets in group 1, calcium sulfate (CS) pellets alone in group 2, and intravenous (i.v.) teicoplanin (6 mg/kg of body weight every 12 h for three doses and then every 24 h up to 4 weeks) in group 3. Animals in group 4 were left untreated. After 6 weeks, the efficacy of the osteomyelitis treatment was evaluated by hematological, radiological, microbiological, and histological examinations. In vitro elution studies showed sustained release of teicoplanin at a therapeutic level over a time period of 3 weeks. The released teicoplanin maintained its antibacterial activity. In vivo, the best therapeutic effect was observed in animals treated with TCS pellets, resulting in significantly lower radiological and histological scores, lower positive rates of MRSA culture and bacterial load, and excellent bone regeneration compared with those treated by CS alone or i.v. teicoplanin, without any local or systemic adverse effects. TCS pellets are an effective alternative to i.v. teicoplanin for the treatment of chronic MRSA osteomyelitis, particularly because teicoplanin is delivered locally while the TCS pellets simultaneously promote bone defect repair.

scholarly journals Synergistic Effect of a Novel Focal Hyperthermia on the Efficacy of Rifampin in Staphylococcal Experimental Foreign-Body Infection

2009 ◽  
Vol 37 (4) ◽  
pp. 1115-1126 ◽  
Author(s):  
G-Y Zou ◽  
H Shen ◽  
Y Jiang ◽  
X-L Zhang
Keyword(s):  
Foreign Body ◽  
Orthopaedic Surgery ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Colony Forming Units ◽  
Rifampin Resistance ◽  
Cure Rates

This study was designed to evaluate the efficacy of focal hyperthermia and rifampin in vitro and in vivo using a rabbit model of foreign-body infection by methicillin-resistant Staphylococcus aureus (MRSA). In vitro studies demonstrated bacterial re-growth and development of rifampin resistance after 24 h with rifampin alone, which was prevented under hyperthermic conditions. For the in vivo studies, rifampin was administered intraperitoneally every 12 h for 7 days to rabbits with MRSA-containing cages implanted into their flanks. When combined with hyperthermia at 39°C, 41°C and 43°C, rifampin significantly reduced in-cage bacterial counts by > 3.0 log10 colony forming units/ml compared with rifampin alone. Eradication of cage-associated infection was achieved more effectively when rifampin was combined with hyperthermia, with cure rates of 70-95% on day 10. Focal hyperthermia combined with rifampin prevented the emergence of rifampin resistance and maintained rifampin efficacy. These findings might have implications for orthopaedic surgery.

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