scholarly journals Effect of Delayed Pulsed-Wave Ultrasound on Local Pharmacokinetics and Pharmacodynamics of Vancomycin-Loaded Acrylic Bone Cement In Vivo

2007 ◽  
Vol 51 (9) ◽  
pp. 3199-3204 ◽  
Author(s):  
Xun-Zi Cai ◽  
Shi-Gui Yan ◽  
Hao-Bo Wu ◽  
Rong-Xin He ◽  
Xue-Song Dai ◽  
...  
Keyword(s):  
Bone Cement ◽  
Low Frequency ◽  
Antimicrobial Efficacy ◽  
Control Group ◽  
Average Intensity ◽  
Acrylic Bone Cement ◽  
Normal Ultrasound ◽  
Ultrasound Group

ABSTRACT This study sought to investigate the effect of delayed pulsed-wave ultrasound with low frequency on drug release from and the antimicrobial efficacy of vancomycin-loaded acrylic bone cement in vivo and the possible mechanism of this effect. After the implantation of cement and the inoculation of Staphylococcus aureus into the bilateral hips of rabbits, ultrasound (average intensity, 300 mW/cm2; frequency, 46.5 kHz; on/off ratio, 20 min/10 min) was applied to animals in the normal ultrasound group (UG0-12) from 0 through 12 h after surgery and to those in the delayed-ultrasound group (UG12-24) from 12 through 24 h after surgery. The control group (CG) was not exposed to ultrasound. Based on vancomycin concentrations in left hip cavities at projected time intervals, the amount of time during which the local drug concentration exceeded the MIC (T >MIC) in UG12-24 was significantly prolonged compared with that in either CG or UG0-12, and the ratios between the areas under the concentration-time curves over 24 h and the MIC for UG0-12 and UG12-24 were both increased compared with that for CG. The greatest reductions in bacterial densities in both right hip aspirates and right femoral tissues at 48 h were achieved with UG12-24. Local hemorrhage in rabbits of UG0-12 during the 12-h insonation was more severe than that in rabbits of UG12-24. Of four variables, the T >MIC and the bioacoustic effect were both identified as parameters predictive of the enhancement of the antimicrobial efficacy of cement by ultrasound. Sustained concentrations above the MIC replaced early high maximum concentrations and long-term subtherapeutic release of the drug, provided that ultrasound was not applied until local hemorrhage was relieved. The enhancement of the antimicrobial efficacy of cement by ultrasound may be attributed to the prolonged T >MIC and the bioacoustic effect caused by ultrasound.

Reduced Modulus Acrylic Bone Cement

1985 ◽  
Vol 55 ◽  
Author(s):  
Alan S. Litsky ◽  
Robert M. Rose ◽  
Clinton T. Rubin
Keyword(s):  
Bone Cement ◽  
Cancellous Bone ◽  
Property Testing ◽  
Acrylic Bone Cement ◽  
Material Interfaces ◽  
Cement Interface ◽  
Reduced Modulus ◽  
Endoprosthesis Loosening

ABSTRACTLoosening is the dominant long-term problem facing joint replacement surgeons and patients. A probable cause of endoprosthesis loosening is the strain singularity at the material interfaces. The concentration of shear at the bone-cement interface leads to micromotion which precipitates a soft-tissue membrane and resorption of the cancellous bone.A more compliant cement would substantially reduce the interfacial stresses and serve as a “pillow” between the prosthetic stem and the cancellous bone. We have developed a surgically-workable formulation of a reduced modulus acrylic bone cement — polybutylmethylmethacrylate (PBMMA) — to test this hypothesis. Materials property testing and in vivo implantation are discussed.

Mechanical Performance and In Vivo Tests of an Acrylic Bone Cement Filled with Bioactive Sepia Officinalis Cuttlebone

2010 ◽  
Vol 21 (1) ◽  
pp. 113-125 ◽  
Author(s):  
S. García-Enriquez ◽  
H. E. R. Guadarrama ◽  
I. Reyes-González ◽  
E. Mendizábal ◽  
C. F. Jasso-Gastinel ◽  
...  
Keyword(s):  
Bone Cement ◽  
Mechanical Performance ◽  
Sepia Officinalis ◽  
Acrylic Bone Cement ◽  
In Vivo Tests

An in Vivo Comparison of Antimicrobial Efficacy of Sodium Hypochlorite and Biopure MTAD™ against Enterococcus Faecalis in Primary Teeth: A qPCR Study

2014 ◽  
Vol 39 (1) ◽  
pp. 30-34 ◽  
Author(s):  
SG Tulsani ◽  
N Chikkanarasaiah ◽  
S Bethur
Keyword(s):  
Root Canal ◽  
Primary Teeth ◽  
Antimicrobial Efficacy ◽  
Permanent Teeth ◽  
Control Group ◽  
Statistical Significant Difference ◽  
Anterior Teeth ◽  
Significant Difference ◽  
Root Canal Irrigant

Objectives: Biopure MTAD™, a new root canal irrigant has shown promising results against the most common resistant microorganism, E. faecalis, in permanent teeth. However, there is lack of studies comparing its antimicrobial effectiveness with NaOCl in primary teeth. The purpose of this study was to compare the in vivo antimicrobial efficacy of NaOCl 2.5% and Biopure MTAD™ against E. faecalis in primary teeth. Study design: Forty non vital single rooted primary maxillary anterior teeth of children aged 4-8 years, were irrigated either with NaOCl 2.5% (n=15), Biopure MTAD™ (n=15) and 0.9% Saline (n=10, control group). Paper point samples were collected at baseline (S1) and after chemomechanical preparation (S2) during the pulpectomy procedure. The presence of E. faecalis in S1 & S2 was evaluated using Real time Polymerase Chain Reaction. Results: Statistical significant difference was found in the antimicrobial efficacy of NaOCl 2.5 % and BioPure MTAD™ when compared to saline (p>0.05). However, no statistical significant difference was found between the efficacies of both the irrigants. Conclusions: NaOCl 2.5% and BioPure MTAD™, both irrigants are equally efficient against E. faecalis in necrotic primary anterior teeth. MTAD is a promising irrigant, however clinical studies are required to establish it as ideal root canal irrigant in clinical practice.

Stimulation at 1-5 Hz does not produce long-term depression or depotentiation in the hippocampus of the adult rat in vivo

1995 ◽  
Vol 74 (4) ◽  
pp. 1793-1799 ◽  
Author(s):  
M. L. Errington ◽  
T. V. Bliss ◽  
G. Richter-Levin ◽  
K. Yenk ◽  
V. Doyere ◽  
...  
Keyword(s):  
Young Animal ◽  
Low Frequency ◽  
Long Term Depression ◽  
Developmentally Regulated ◽  
Adult Rats ◽  
Adult Rat ◽  
Area Ca1 ◽  
Awake Rat

1. We examined the efficacy of low-frequency trains (1-5 Hz) in producing long-term depression (LTD) or depotentiation in the hippocampus of the awake adult rat and in anesthetized rats aged from 10 days to 3 mo. 2. In the dentate gyrus we found no evidence that low-frequency trains produce either depotentiation or LTD in the awake, adult animal or in the anesthetized animal at any age tested (10 days-adult). 3. In area CA1 of both awake and anesthetized adult rats, we also found no evidence that low-frequency trains induced either LTD or depotentiation. Only in area CA1 of very young rats (10-11 days) was clear evidence for LTD and depotentiation obtained; at this age experiments were only possible in anesthetized animals. By 16 days, the ability to display both LTD and depotentiation was lost. 4. These experiments suggest that repetitive low-frequency stimulation evokes a developmentally regulated form of activity-dependent depression that in the hippocampus is limited to specific pathways in the young animal. Our results leave open the question of whether alternative patterns of activity can induce LTD and/or depotentiation in the adult awake rat.

Safety and long-term maintenance of anti-HER2 immunity following booster inoculations of the E75 breast cancer vaccine.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2529-2529
Author(s):  
Raetasha Sheavette Dabney ◽  
Diane F Hale ◽  
Timothy J Vreeland ◽  
Guy T. Clifton ◽  
Alan K. Sears ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Vaccine ◽  
Peptide Vaccine ◽  
Control Group ◽  
Breast Cancer Patients ◽  
Recurrence Rates ◽  
Specific Immunity

2529 Background: We have completed accrual and are in the follow up portion of phase I/II clinical trials evaluating the E75 HER2 peptide vaccine. E75 has been proven safe, capable of stimulating HER2 immunity, and effective in decreasing breast cancer recurrence rates. During the conduct of this trial, it was noted that E75-specific immunity waned after the Primary Vaccine Series (PVS) which corresponded with late recurrences. To maintain long-term immunity, a voluntary booster program was started. Here we present analysis of the booster inoculations. Methods: The trial enrolled node-positive or high-risk, node-negative breast cancer patients (pts) with tumors expressing any level of HER2 (IHC 1-3+). HLA-A2/A3+ pts comprised the vaccine group (VG), HLA-A2/A3- pts were followed as the control group (CG). The VG received 4-6 monthly inoculations of E75+GM-CSF. Volunteer booster program pts (BG) received inoculations every 6 months after the PVS. Pts were monitored for toxicities, in vivo responses by local reactions (LR) and DTH, and in vitro responses measured by enumeration of E75 specific cytotoxic T lymphocytes. Results: 53 pts received at least 1 booster, 34 received 2, 24 three, 20 four, 12 five, and 8 at least 6. 24% of pts had no local toxicity, 73% Grade 1 (G1), 3% G2. 74% had no systemic toxicity, 35% G1, 1% G2. LRs increased significantly from the initial vaccine (R1) during PVS to each booster (B) (R1: 59.5±3.1 v B1: 89.2±3.3, p<0.001; v B2: 95.15±5, p<0.001; v B3: 86.63±5.5, p<0.001; v B4: 83.26±4.6, p=<0.001; v B5: 80.67±6.7, p=0.006; v B6: 78.75±9.4, p=0.04). Dimer values increased from the end of PVS to each post-booster value (pre B1:1.29±0.25 v post B1: 1.46±0.38; post B2: 1.41±0.4; post B3: 1.84±0.35; post B4: 2.23±0.4; post B5:1.94±0.31; post B6: 2.73±0.09, p=0.02). At median 60 months, the recurrence rate for BG was 3.8% vs 18.9% in the CG (p=0.01). Conclusions: Booster inoculations are well-tolerated and appear to assist in the maintenance of long term peptide-specific immunity. Boosted pts have improved recurrence rates. Based on the success of this program, we have incorporated the practice of booster inoculations in our current cancer vaccine trials.

Long-term hyperprolactinaemia reduces basal but not androgen-stimulated oestradiol production in small antral follicles of the rat ovary

1991 ◽  
Vol 129 (3) ◽  
pp. 357-362 ◽  
Author(s):  
J. A. Jonassen ◽  
S. P. Baker ◽  
A. S. McNeilly
Keyword(s):  
Female Rats ◽  
Control Group ◽  
Aromatase Activity ◽  
Treatment Groups ◽  
Antral Follicles ◽  
Rat Ovary ◽  
Cervical Stimulation ◽  
Oestradiol Production

ABSTRACT Hyperprolactinaemia disrupts fertility in many species, perhaps by inhibiting ovarian follicular steroidogenesis. The present studies measured oestradiol and progesterone secretion from isolated follicles from rats rendered hyperprolactinaemic in one of two ways. Sustained hyperprolactinaemia was induced by transplantation of two donor pituitary grafts under the renal capsule of adult female rats; grafts remained in place for 3 months. Transient hyperprolactinaemia was induced by pseudopregnancy initiated by cervical stimulation. Small antral follicles were isolated from both groups of rats 8–10 days after the previous vaginal oestrous smear and also from a control group of dioestrous female rats. Follicles were incubated for 3 h in the presence or absence of human chorionic gonadotrophin (hCG) or testosterone. Basal and hCG-stimulated oestradiol production were each reduced in follicles from both hyperprolactinaemic groups, relative to follicles from dioestrous control rats. In contrast, in the presence of testosterone, all groups of follicles produced comparable amounts of oestradiol. hCG stimulated comparable progesterone production by follicles from all three treatment groups. Testosterone elicited smaller increases in progesterone accumulation by follicles from all in-vivo groups. Reduced basal and gonadotrophin-stimulated, but not androgen-stimulated, oestradiol accumulation suggests that androgen production rather than aromatase activity in small antral follicles may be impaired by long-term hyperprolactinaemia. Journal of Endocrinology (1991) 129, 357–362

scholarly journals PO-147 Effect of Exercise-induced Fatigue on the Electrical Activity of the External Globus Pallidus Neurons in rats

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Hao Yu ◽  
Lijuan Hou ◽  
Jing Ma ◽  
Zhifeng Wang ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Globus Pallidus ◽  
Low Frequency ◽  
Extracellular Recording ◽  
Central Fatigue ◽  
Control Group ◽  
Indirect Pathway ◽  
Exercise Induced ◽  
Exercise Fatigue

Objective The motor cortex (MC) stimulation-induced unitary responses of globus pallidus external segment (GPe) neurons in control and exercise induced-fatigue rats were recorded in vivo to examine the role of cortical-striatum-external globus pallidal pathway in the mechanism of central fatigue. Methods 32 Clean healthy male Wistar rats (260~300g), were randomly divided into 4 groups: control group (Control), 1-day fatigue group (1FG), 3-day fatigue group (3FG) and 7-day fatigue group (7FG). Rats were subjected to a 5-day adaptive treadmill training. Modified Bedford treadmill exercise with progressively increasing load was used to creat the exercise fatigue model. （3 levels:8.2 m/min, 15 min; 15m/min, 15 min; 20 m/min, lasting till exhaustion） The spontaneous unit activity and responses to MC stimulation of GPe neurons were recorded by the electrophysiological technique of extracellular recording of glass microelectrodes. Results The results showed that the firing frequency of high-frequency firing with pause (HFP) and low frequency firing with burst (LFB) in the GPe of 1FG was comparable with that of control group (P>0.05). However in 3FG and 7FG , the percentage of HFP neuron was significantly decreased (P<0.05), while the proportion of LFB was significantly increased (P<0.05), and the average firing rate of LFB was higher and inter spike intervals (ISI) was significantly lower than that of the control group. With 200μA electrical stimulation, the explosive discharge of GPe neurons was attenuated after fatigue in rats. The response of GPe neurons to variable frequency stimulation in exhausted model groups was stronger than that of the control group.MC-stimulation typically induced a triphasic response composed of early excitation, inhibition, and late excitation in GPe neurons. The population of neurons showing a short inhibition slightly increased in 3FG and 7FG. Conclusions 1. The results confirmed that GPe is an important nucleus of basal ganglia involved in the regulation of exercise-induced fatigue by the change of spontaneous activity. Electrical stimulation on the cortex can alter response patterns of GPe neurons in exercise-induced fatigue rats, the results confirmed that the Ctx-Str-GPe neural pathway is involved in the regulation of exercise fatigue, and the indirect pathway is over-activated.

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