scholarly journals Early changes in serum osteocalcin and body weight are predictive of implant fixation in a rat model of implant loosening

2019 ◽  
Vol 38 (6) ◽  
pp. 1216-1227 ◽  
Author(s):  
Brittany M. Wilson ◽  
Meghan M. Moran ◽  
Matthew J. Meagher ◽  
Ryan D. Ross ◽  
Maleeha Mashiatulla ◽  
...  
Keyword(s):  
Body Weight ◽  
Rat Model ◽  
Serum Osteocalcin ◽  
Implant Loosening ◽  
Implant Fixation

scholarly journals Bone turnover markers correlate with implant fixation in a rat model using LPS-doped particles to induced implant loosening

2012 ◽  
Vol 100A (4) ◽  
pp. 918-928 ◽  
Author(s):  
Shuo Liu ◽  
Amarjit S. Virdi ◽  
Kotaro Sena ◽  
W. Frank Hughes ◽  
Dale R. Sumner
Keyword(s):  
Bone Turnover ◽  
Rat Model ◽  
Bone Turnover Markers ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Turnover Markers

Progressive Loss of Implant Fixation in a Preclinical Rat Model of Cemented Knee Arthroplasty

2020 ◽  
Author(s):  
Kenneth A Mann ◽  
Mark A Miller ◽  
Jeffrey K Rossow ◽  
Megan E Tatusko ◽  
Jason A Horton ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Rat Model ◽  
Implant Fixation ◽  
Progressive Loss

Brown adipose tissue activation in a rat model of Parkinson’s disease

2017 ◽  
Vol 313 (6) ◽  
pp. E731-E736 ◽  
Author(s):  
Wenjuan Wang ◽  
Xiangzhi Meng ◽  
Chun Yang ◽  
Dongliang Fang ◽  
Xuemeng Wang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Weight Loss ◽  
Body Weight ◽  
Adipose Tissue ◽  
Energy Expenditure ◽  
Brown Adipose Tissue ◽  
Energy Intake ◽  
Rat Model ◽  
Sympathetic Denervation ◽  
Brown Adipose

Loss of body weight and fat mass is one of the nonmotor symptoms of Parkinson’s disease (PD). Weight loss is due primarily to reduced energy intake and increased energy expenditure. Whereas inadequate energy intake in PD patients is caused mainly by appetite loss and impaired gastrointestinal absorption, the underlying mechanisms for increased energy expenditure remain largely unknown. Brown adipose tissue (BAT), a key thermogenic tissue in humans and other mammals, plays an important role in thermoregulation and energy metabolism; however, it has not been tested whether BAT is involved in the negative energy balance in PD. Here, using the 6-hydroxydopamine (6-OHDA) rat model of PD, we found that the activity of sympathetic nerve (SN), the expression of Ucp1 in BAT, and thermogenesis were increased in PD rats. BAT sympathetic denervation blocked sympathetic activity and decreased UCP1 expression in BAT and attenuated the loss of body weight in PD rats. Interestingly, sympathetic denervation of BAT was associated with decreased sympathetic tone and lipolysis in retroperitoneal and epididymal white adipose tissue. Our data suggeste that BAT-mediated thermogenesis may contribute to weight loss in PD.

scholarly journals Finite-element analysis of the influence of tibial implant fixation design of total ankle replacement on bone–implant interfacial biomechanical performance

2020 ◽  
Vol 28 (3) ◽  
pp. 230949902096612
Author(s):  
Jian Yu ◽  
Chao Zhang ◽  
Wen-Ming Chen ◽  
Dahang Zhao ◽  
Pengfei chu ◽  
...  
Keyword(s):  
Finite Element ◽  
Total Ankle Replacement ◽  
Implant Design ◽  
Fixation Method ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Bone Resection ◽  
Bone Implant ◽  
Initial Stability ◽  
Ankle Replacement

Purpose: Implant loosening in tibia after primary total ankle replacement (TAR) is one of the common postoperative problems in TAR. Innovations in implant structure design may ideally reduce micromotion at the bone–implant interface and enhance the bone-implant fixation and initial stability, thus eventually prevents long-term implant loosening. This study aimed to investigate (1) biomechanical characteristics at the bone–implant interface and (2) the influence of design features, such as radius, height, and length. Methods: A total of 101 finite-element models were created based on four commercially available implants. The models predicted micromotion at the bone–implant interface, and we investigated the impact of structural parameters, such as radius, length, and height. Results: Our results suggested that stem-type implants generally required the highest volume of bone resection before implantation, while peg-type implants required the lowest. Compared with central fixation features (stem and keel), peripherally distributed geometries (bar and peg) were associated with lower initial micromotions. The initial stability of all types of implant design can be optimized by decreasing fixation size, such as reducing the radius of the bars and pegs and lowering the height. Conclusion: Peg-type tibial implant design may be a promising fixation method, which is required with a minimum bone resection volume and yielded minimum micromotion under an extreme axial loading scenario. Present models can serve as a useful platform to build upon to help physicians or engineers when making incremental improvements related to implant design.

scholarly journals Hyperandrogenism and Insulin Resistance, Not Changes in Body Weight, Mediate the Development of Endothelial Dysfunction in a Female Rat Model of Polycystic Ovary Syndrome (PCOS)

Endocrinology ◽  
2015 ◽  
Vol 156 (11) ◽  
pp. 4071-4080 ◽  
Author(s):  
Amanda Hurliman ◽  
Jennifer Keller Brown ◽  
Nicole Maille ◽  
Maurizio Mandala ◽  
Peter Casson ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Endothelial Dysfunction ◽  
Polycystic Ovary Syndrome ◽  
Rat Model ◽  
Polycystic Ovary ◽  
Phase 1 ◽  
Ovary Syndrome

This study was designed to differentiate the contributions of hyperandrogenism, insulin resistance (IR), and body weight to the development of endothelial dysfunction in polycystic ovary syndrome and determine the effectiveness of insulin sensitization and antiandrogenic therapy after the establishment of vascular and metabolic dysfunction using a rat model of polycystic ovary syndrome. We hypothesized that the observed endothelial dysfunction was a direct steroidal effect, as opposed to changes in insulin sensitivity or body weight. Prepubertal female rats were randomized to the implantation of a pellet containing DHT or sham procedure. In phase 1, DHT-exposed animals were randomized to pair feeding to prevent weight gain or metformin, an insulin-sensitizing agent, from 5 to 14 weeks. In phase 2, DHT-exposed animals were randomized to treatment with metformin or flutamide, a nonsteroidal androgen receptor blocker from 12 to 16 weeks. Endothelial function was assessed by the vasodilatory response of preconstricted arteries to acetylcholine. Serum steroid levels were analyzed in phase 1 animals. Fasting blood glucose and plasma insulin were analyzed and homeostasis model assessment index calculated in all animals. Our data confirm the presence of endothelial dysfunction as well as increased body weight, hypertension, hyperinsulinemia, and greater IR among DHT-treated animals. Even when normal weight was maintained through pair feeding, endothelial dysfunction, hyperinsulinemia, and IR still developed. Furthermore, despite weight gain, treatment with metformin and flutamide improved insulin sensitivity and blood pressure and restored normal endothelial function. Therefore, the observed endothelial dysfunction is most likely a direct result of hyperandrogenism-induced reductions in insulin sensitivity, as opposed to weight gain.

scholarly journals Omentectomy Prevents Metabolic Syndrome By Reducing Appetite and Body Weight In A Diet-Induced Obesity Rat Model

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Inmaculada García-Ruiz ◽  
Pablo Solís-Muñoz ◽  
Daniel Fernández-Moreira ◽  
Montserrat Grau ◽  
Maria Teresa Muñoz-Yagüe ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Body Weight ◽  
Rat Model ◽  
Diet Induced Obesity

scholarly journals Influence of Inoculum Effect on the Efficacy of Daptomycin Monotherapy and in Combination with β-Lactams against Daptomycin-Susceptible Enterococcus faecium Harboring LiaSR Substitutions

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Razieh Kebriaei ◽  
Seth A. Rice ◽  
Kavindra V. Singh ◽  
Kyle C. Stamper ◽  
An Q. Dinh ◽  
...  
Keyword(s):  
Body Weight ◽  
Bloodstream Infection ◽  
Clinical Isolate ◽  
Rat Model ◽  
Enterococcus Faecium ◽  
Dose Regimen ◽  
Clinical Isolates ◽  
Content Type ◽  
Inoculum Effect ◽  
Derivatives Of

ABSTRACT Enterococcus faecium isolates that harbor LiaFSR substitutions but are phenotypically susceptible to daptomycin (DAP) by current breakpoints are problematic, since predisposition to resistance may lead to therapeutic failure. Using a simulated endocardial vegetation (SEV) pharmacokinetic/pharmacodynamic (PK/PD) model, we investigated DAP regimens (6, 8, and 10 mg/kg of body weight/day) as monotherapy and in combination with ampicillin (AMP), ceftaroline (CPT), or ertapenem (ERT) against E. faecium HOU503, a DAP-susceptible strain that harbors common LiaS and LiaR substitutions found in clinical isolates (T120S and W73C, respectively). Of interest, the efficacy of DAP monotherapy, at any dose regimen, was dependent on the size of the inoculum. At an inoculum of ∼109 CFU/g, DAP doses of 6 to 8 mg/kg/day were not effective and led to significant regrowth with emergence of resistant derivatives. In contrast, at an inoculum of ∼107 CFU/g, marked reductions in bacterial counts were observed with DAP at 6 mg/kg/day, with no resistance. The inoculum effect was confirmed in a rat model using humanized DAP exposures. Combinations of DAP with AMP, CPT, or ERT demonstrated enhanced eradication and reduced potential for resistance, allowing de-escalation of the DAP dose. Persistence of the LiaRS substitutions was identified in DAP-resistant isolates recovered from the SEV model and in DAP-resistant derivatives of an initially DAP-susceptible clinical isolate of E. faecium (HOU668) harboring LiaSR substitutions that was recovered from a patient with a recurrent bloodstream infection. Our results provide novel data for the use of DAP monotherapy and combinations for recalcitrant E. faecium infections and pave the way for testing these approaches in humans.

scholarly journals Efficacy of Ceftaroline against Methicillin-Susceptible Staphylococcus aureus Exhibiting the Cefazolin High-Inoculum Effect in a Rat Model of Endocarditis

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Kavindra V. Singh ◽  
Truc T. Tran ◽  
Esteban C. Nannini ◽  
Vincent H. Tam ◽  
Cesar A. Arias ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Body Weight ◽  
Infective Endocarditis ◽  
Rat Model ◽  
Type A ◽  
Treated Group ◽  
Content Type ◽  
High Inoculum ◽  
Inoculum Effect

ABSTRACT Certain Staphylococcus aureus strains exhibit an inoculum effect (InE) with cefazolin (CFZ) that has been associated with therapeutic failures in high-inoculum infections. We assessed the in vitro activities of ceftaroline (CPT), CFZ, and nafcillin (NAF) against 17 type A β-lactamase (βla)-producing, methicillin-susceptible S. aureus (MSSA) strains, including the previously reported TX0117, which exhibits the CFZ InE, and its βla-cured derivative, TX0117c. Additionally, we determined the pharmacokinetics of CPT in rats after single intramuscular doses of 20 and 40 mg/kg of body weight and evaluated the activities of CPT (40 mg/kg every 8 h [q8h]), CFZ, and NAF against TX0117 and TX0117c in a rat model of infective endocarditis. No InE was observed for CPT or NAF, whereas a marked InE was detected for CFZ (MIC, 8 to ≥128 μg/ml). CPT and NAF treatment against TX0117 resulted in mean bacterial counts of 2.3 and 2.1 log10 CFU/g in vegetations, respectively, compared to a mean of 5.9 log10 CFU/g in the CFZ-treated group (CPT and NAF versus CFZ, P = 0.001; CPT versus NAF, P = 0.9830). Both CFZ and CPT were efficacious against the βla-cured derivative, TX0117c, compared to time zero (t 0) (P = <0.0001 and 0.0015, respectively). Our data reiterate the in vivo consequences of the CFZ InE and show that CPT is not affected by this phenomenon. CPT might be considered for high-inoculum infections caused by MSSA exhibiting the CFZ InE.

The Influence of Biomechanical Factors at the Tissue-Biomaterial Interface

1987 ◽  
Vol 110 ◽  
Author(s):  
John B. Brunski ◽  
J. A. Hipp ◽  
G. V. B. Cochran
Keyword(s):  
Relative Motion ◽  
Implant Failure ◽  
Implant Loosening ◽  
Implant Fixation ◽  
Interfacial Stresses ◽  
In Vivo Experiment ◽  
Number Of Factors ◽  
Biomechanical Factors

AbstractWhen an implant is placed into bone, an interface is created. This interface has a critical biomechanical function: it must support the implant in bone. However, failure of implant fixation (i.e., implant “loosening”), continues to be a leading cause of implant failure [1,2]. While there are a number of factors involved in this problem, it is recognized that biomechanical factors play a role, and this paper reviews the more important factors, including relative motion and interfacial stresses and strains. Also, it presents results from a recent in vivo experiment on controlled loading of an interface.

Vagotomy Suppresses Body Weight Gain in a Rat Model of Gastric Banding

2010 ◽  
Vol 27 (4) ◽  
pp. 302-306 ◽  
Author(s):  
Hitoshi Kanno ◽  
Teruo Kiyama ◽  
Itsuo Fujita ◽  
Shunji Kato ◽  
Eiji Uchida ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Gastric Banding ◽  
Rat Model ◽  
Body Weight Gain
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