• Journal of Periodontal and Implant Science
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• v.48 no.5
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• pp.305-316
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• 2018

Purpose: The aim of the present study was to evaluate the biocompatibility and barrier function of mussel adhesive protein (MAP)-loaded collagen membranes in guided bone regeneration (GBR). Methods: Eight male New Zealand white rabbits were used. Four circular defects (diameter: 8 mm) were created in the calvarium of each animal. The defects were randomly assigned to 1) a negative control group, 2) a cyanoacrylate (CA)-loaded collagen membrane group (the CA group), 3) a MAP-loaded collagen membrane group (the MAP group), and 4) a group that received a polycaprolactone block with MAP-loaded collagen membrane (the MAP-PCL group). Specimens were harvested at 2 weeks (n=4) and 8 weeks (n=4) postoperatively for observational histology and histometric analysis. Results: In the histologic analysis, MAP was completely absorbed without any byproducts. In contrast, some of the CA adhesive remained, showing an inflammatory reaction, at 8 weeks. In the MAP-PCL group, the MAP-loaded collagen membranes served as a barrier membrane despite their fast degradation in GBR. No significant difference was found in the amount of new bone between the MAP-PCL and MAP groups ($1.82{\pm}0.86mm^2$ and $2.60{\pm}0.65mm^2$, respectively). Conclusions: The MAP-loaded collagen membrane functioned efficiently in this rabbit calvarial GBR model, with excellent biocompatibility. Further research is needed to assess clinical applications in defect types that are more challenging for GBR than those used in the current model.

• Journal of Conservation Science
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• v.33 no.4
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• pp.255-266
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• 2017

Chemically derived pesticides have been used to prevent biological damage to domestic cultural property. However, their use is gradually being restricted due to the harmful effects on the human body and environment. Therefore, there is a growing interest in the search for new antifungal biopharmaceuticals whose safety has been confirmed by toxicity evaluation through animal experiments. This paper presents methods of toxicity evaluation of natural biocides using Sprague-Dawley rats and New Zealand White (NZW) rabbits. Safety of the natural biocide extract of Asarum sieboldii was evaluated using single-dose oral and dermal toxicity tests in Sprague-Dawley rats, and eye and skin irritation tests in NZW rabbits. The extract has proven antimicrobial and insecticidal activities against wood-rotting fungi and termites. After single oral administration to rats, the $LD_{50}$ values were determined to be over 4,000 and 2,000 mg/kg for males and females, respectively. After single dermal administration to rats, the $LD_{50}$ values exceeded 10,000 mg/kg for both males and females. The extract was identified to be non-irritant to the rabbit eye, and only slightly irritant to the rabbit skin. In this study, we confirmed the safety of the A sieboldii extract through animal testing. Due to the harmfulness of humidifier disinfectants, focus is on the safety of chemical pesticides, and toxicity evaluation is suggested as the basic method for hazard evaluation.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.635-648
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• 2005

The procedure that enhances osteogenesis and shortens the healing period is required for successful implant therapy. It has been introduced that osteogenesis is enhanced by the generation of electric field. Many researchers have demonstrated that application of electric and electromagnetic field promote bone formation. It also has been shown that electrical stimulation enhances peri-implant bone formation. Recently, several investigators have reported that noninvasive electrical stimulation using negatively charged electret such as polytetrafluoroethylene(PTFE) promotes osteogenesis. Therefore, we were interested in the effect of noninvasive electrical stimulation using negatively charged electret on the periimplant bone healing. After titanium implant were installed in the proximal tibial metaphysis of New Zealand white rabbit, negatively charged PTFE membrane fabricated by corana dischage was inserted into the inner hole of the experimental implant and noncharged membrane was applied into control implant. After 4 weeks of healing, histomorphometric analysis was performed to evaluate peri-implant bone response. The histomorphometric evaluations demonstrated experimental implant tended to have higher values in the total bone-to-implant contact ratio(experimental ; $49.9{\pm}13.52%$ vs control ; $37.5{\pm}19.44%$) , the marrow bone contact ratio(experimental ; $34.94{\pm}13.32%$ vs control ; $24.15{\pm}13.69%$), amount of newly formed bone in the endosteal region(experimental ; $1.00{\pm}0.30mm$ vs control ; $0.61{\pm}0.24mm$) and bone area in the medullary canal(experimental ; $13.55{\pm}4.98%$ vs control ; $9.03{\pm}3.05%$). The mean values of the amount of newly formed bone(endosteal region) and bone area(medullary canal) of the experimental implant demonstrated a statistically significant difference as compared to the control implant(p<0.05). In conclusion, noninvasive electrical stimulation using negatively charged electret effectively promoted peri-implant new bone formation in this study. This method is expected to be used as one of the useful electrical stimulation for enhancing bone healing response in the implant therapy

• Journal of radiological science and technology
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• v.35 no.2
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• pp.165-172
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• 2012

We investigated the vascular characteristics of tumors and normal tissue using perfusion CT in the rabbit brain tumor model. The VX2 carcinoma concentration of $1{\times}10^7$ cells/ml(0.1ml) was implanted in the brain of nine New Zealand white rabbits (weight: 2.4kg-3.0kg, mean: 2.6kg). The perfusion CT was scanned when the tumors were grown up to 5mm. The tumor volume and perfusion value were quantitatively analyzed by using commercial workstation (advantage windows workstation, AW, version 4.2, GE, USA). The mean volume of implanted tumors was $316{\pm}181mm^3$, and the biggest and smallest volumes of tumor were 497 $mm^3$ and 195 $mm^3$, respectively. All the implanted tumors in rabbits are single-nodular tumors, and intracranial metastasis was not observed. In the perfusion CT, cerebral blood volume (CBV) were $74.40{\pm}9.63$, $16.08{\pm}0.64$, $15.24{\pm}3.23$ ml/100g in the tumor core, ipsilateral normal brain, and contralateral normal brain, respectively ($p{\leqq}0.05$). In the cerebral blood flow (CBF), there were significant differences between the tumor core and both normal brains ($p{\leqq}0.05$), but no significant differences between ipsilateral and contralateral normal brains ($962.91{\pm}75.96$ vs. $357.82{\pm}12.82$ vs. $323.19{\pm}83.24$ ml/100g/min). In the mean transit time (MTT), there were significant differences between the tumor core and both normal brains ($p{\leqq}0.05$), but no significant differences between ipsilateral and contralateral normal brains ($4.37{\pm}0.19$ vs. $3.02{\pm}0.41$ vs. $2.86{\pm}0.22$ sec). In the permeability surface (PS), there were significant differences among the tumor core, ipsilateral and contralateral normal brains ($47.23{\pm}25.45$ vs. $14.54{\pm}1.60$ vs. $6.81{\pm}4.20$ ml/100g/min)($p{\leqq}0.05$). In the time to peak (TTP) were no significant differences among the tumor core, ipsilateral and contralateral normal brains. In the positive enhancement integral (PEI), there were significant differences among the tumor core, ipsilateral and contralateral brains ($61.56{\pm}16.07$ vs. $12.58{\pm}2.61$ vs. $8.26{\pm}5.55$ ml/100g). ($p{\leqq}0.05$). In the maximum slope of increase (MSI), there were significant differences between the tumor core and both normal brain($p{\leqq}0.05$), but no significant differences between ipsilateral and contralateral normal brains ($13.18{\pm}2.81$ vs. $6.99{\pm}1.73$ vs. $6.41{\pm}1.39$ HU/sec). Additionally, in the maximum slope of decrease (MSD), there were significant differences between the tumor core and contralateral normal brain($p{\leqq}0.05$), but no significant differences between the tumor core and ipsilateral normal brain($4.02{\pm}1.37$ vs. $4.66{\pm}0.83$ vs. $6.47{\pm}1.53$ HU/sec). In conclusion, the VX2 tumors were implanted in the rabbit brain successfully, and stereotactic inoculation method make single-nodular type of tumor that was no metastasis in intracranial, suitable for comparative study between tumors and normal tissues. Therefore, perfusion CT would be a useful diagnostic tool capable of reflecting the vascularity of the tumors.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.6
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• pp.477-484
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• 2022

In this study, the cartridge part of the focused ultrasound stimulation system was used as a sample to conduct a skin irritation test and a skin sensitization test through animal experiments among the tests related to GLP (Good Laboratory Practice), a medical device safety evaluation standard. The test was conducted after IACUC approval using 6 female New Zeland White Rabbits. The polar and non-polar stimulation indices were all '0.0'. In addition, in the case of skin sensitization evaluation, 30 guinea pigs approved by IACUC were divided into control and experimental groups, and all induction and induction steps were applied using the eluate itself without separate dilution of the test sample and blank test solution. As a result of the experiment, the skin reaction grade of the control animal was 0 grade, and there was no animal showing more than 1 grade in the skin reaction of the test animal. As a result of both tests, no abnormal skin symptoms were observed, and when applied to the human body to treat patients, the test materials used in the tests will investigate the stability of whether any diseases that cause skin abnormal symptoms will occur.

• Archives of Plastic Surgery
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• v.41 no.6
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• pp.638-646
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• 2014

Background The combination of polycaprolactone and hyaluronic acid creates an ideal environment for wound healing. Hyaluronic acid maintains a moist wound environment and accelerates the in-growth of granulation tissue. Polycaprolactone has excellent mechanical strength, limits inflammation and is biocompatible. This study evaluates the safety and efficacy of bio-conjugated polycaprolactone membranes (BPM) as a wound dressing. Methods 16 New Zealand white rabbits were sedated and local anaesthesia was administered. Two $3.0{\times}3.0cm$ full-thickness wounds were created on the dorsum of each rabbit, between the lowest rib and the pelvic bone. The wounds were dressed with either BPM (n=12) or Mepitel (n=12) (control), a polyamide-silicon wound dressing. These were evaluated macroscopically on the 7th, 14th, 21st, and 28th postoperative days for granulation, re-epithelialization, infection, and wound size, and histologically for epidermal and dermal regeneration. Results Both groups showed a comparable extent of granulation and re-epithelialization. No signs of infection were observed. There was no significant difference (P>0.05) in wound size between the two groups. BPM (n=6): $8.33cm^2$, $4.90cm^2$, $3.12cm^2$, $1.84cm^2$; Mepitel (n=6): $10.29cm^2$, $5.53cm^2$, $3.63cm^2$, $2.02cm^2$; at the 7th, 14th, 21st, and 28th postoperative days. The extents of epidermal and dermal regeneration were comparable between the two groups. Conclusions BPM is comparable to Mepitel as a safe and efficacious wound dressing.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.6
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• pp.459-466
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• 2011

Purpose: This study evaluated the capability of bone formation with silk fibroin/nano-hydroxyapatite/corn starch composite scaffold as a bone defect replacement matrix when grafted in a calvarial bone defect of rabbits $in$ $vivo$. Methods: Ten New Zealand white rabbits were used for this study and bilateral round-shaped defects were formed in the parietal bone (diameter: 8.0 mm). The silk fibroin 10% nano-hydroxyapatite/30% corn starch/60% composite scaffold was grafted into the right parietal bone (experimental group). The left side (control group) was grafted with a nano-hydroxyapatite (30%)/corn starch (70%) scaffold. The animals were sacrificed at 4 weeks and 8 weeks. A micro-computerized tomography (${\mu}CT$) of each specimen was taken. Subsequently, the specimens were decalcified and stained with Masson's trichrome for histological and histomorphometric analysis. Results: The average ${\mu}CT$ and histomorphometric measures of bone formation were higher in the control group than in the experimental group at 4 weeks and 8 weeks after surgery though not statistically significant ($P$ >0.05). Conclusion: The rabbit calvarial defect was not successfully repaired by silk fibroin/nano-hydroxyapatite/corn starch composite scaffold and may have been due to an inflammatory reaction caused by silk powder. In the future, the development of composite bone graft material based on various components should be performed with caution.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.659-681
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• 2001

Platelet-rich plasma(PRP) has been known to increase the rate and degree of bone formation by virtue of growth factors in concentrated platelets. Although its great healing effect on bone defect or pre-implantation site preparation in conjunction with bone substitute has been reported, the effect associated with implant is unknown. The purpose of this study was to investigate the effect of PRP on rapid osseointegration of endosseous dental implants in the rabbit tibiae. Twenty two adult female New Zealand white rabbits, weighing approximately 2.7-3.3kg, were used for this study. Twelve of the 22 animals were used for histomorphometric analysis and ten of the 22 were for removal torque test. Each animal received two implants in each tibia (two treated with PRP and two as control) and was given fluorochrome intramuscularly. For histomorphometric analysis, rabbits were divided into four groups according to the healing period. At 1 week, 2 weeks, 4 weeks and 8 weeks postoperatively, each three animals were sacrificed serially and the amount and rate of bone formation around dental implant were examined on the undecalcified sections under fluorescent microscope, polarized microscope and light microscope connected to a personal computer equipped with image analysis system. For removal torque test, rabbits were divided into two groups and removal torque tests were performed at 4 weeks, 10 weeks after implant placement. In total, 88 screw shaped, commercially pure titanium implants (Neoplant, Neobiotech, Seoul, Korea) were used in this study. Labeling pattern reflected differences of two groups in bone formation rate at each period. Histomorphometrically, PRP group showed significantly higher bone volume within threads compared to control group at 2 weeks ($70.30{\pm}4.96%$ vs. $50.68{\pm}6.33%$; P < .01) and 4 weeks ($82.59{\pm}5.94%$ vs. $72.94{\pm}4.57%$; P < .05 ). PRP group at 1, 2 and 4 weeks revealed similar degree of bone volume formation comparable to control group at 2, 4 and 8 weeks, respectively. On the other hand, while PRP group showed higher bone-implant contact ($47.37{\pm}8.09%$) than control group ($33.16{\pm}13.47%$) at 2 weeks, there were no significant differences between PRP group and control group for any experimental period. Removal torque values also showed no significant differences between PRP group and control group at any experimental period (P > .05). These findings imply that PRP could induce rapid, more bone formation around implant during early healing period and get faster secondary stability for reducing healing period, though it has not induced bone maturation enough to resist functional loading.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.5
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• pp.594-605
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• 2006

Statement of problem: Modification of titanium implant surface has potential to ensure clinically favorable performance that several surface modification technologies have been introduced. Among the methods. anodizing method and sol-gel hydroxyapatite coating method have gained much interest due to its roughness and chemical composition of the coating layer, but more of its biocompatibility result is required. Purpose : The purpose of this study was to compare bone-implant interface shear strength of four different surface treated implants as time elapsed. Resonance frequency analysis(RFA) and removal torque measurement methods were employed to measure implant stability at one week and six week after implantation. Material and method: A total of 80 screw-shaped implant [20 machined, 20 resorbable media blasted(RBM), 20 anodized, and 20 anodized+hydroxyapatite sol-gel coated] were prepared, and one of each group was implanted in the tibia of a New Zealand white rabbit that total 20 of them were used. In order to test the implant stability and implant-tissue interface contact changing in the bone bed, each 10 rabbit were sacrificed 1 week and 6 week later while resonance frequency and removal torque were measured. One-way analysis of variance and the Tukey test were used for statistical analysis. Results : The results were as follows. 1. There was no statistically significant difference of implant stability quotients(ISQ) value in RFA between individual groups after 1 week of implantation and 6 weeks(p>0.05). But, there was statistically significant increase of ISQ value in 6 weeks group compared to 1 week group(p<0.05). 2. There was no statistically significant difference in removal torque analysis between individual groups after 1 week of implantation and 6 weeks(p>0.05). but there was statistically significant increase in all 4 groups after 6 weeks compared to 1 week later(p<0.05). 3. There was no statistically significant difference in removal torque analysis between anodized group and HA coating after anodic oxidation 6 weeks later(p>0.05), but significant difference was appeared in both groups compared to RBM group and smooth-machined group(p<0.05). Conclusions : It can be suggested that changes in surface characteristics affect bone reactions. Anodized and anodized+hydroxyapatite sol-gel coating showed significantly improved bone tissue response to implants, but further study on the effect of hydroxyapatite dissolution is needed.

• Parasites, Hosts and Diseases
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• v.32 no.4
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• pp.223-230
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• 1994

Clonorchiasis is an important parasitic disease of humans in Korea. The present study intended to compare sonographic findings with histopathological changes in experimental clonorchiasis. Eighteen New Zealand white rabbits were infected with metacercariae of Cknorchis sinensis, and examined 4, 10, and 22 weeks post-infection (PI). Four infected rabbits were treated with praziquantel 10 weeks PI and were examined 12 weeks after treatment. Sonography revealed mild to severe dilatation of the intrahepatic ducts (IHDD) and slightly increased periductal echoes in 12 out of 14 rabbits at 4 weeks PI, and all of the animals after 10 and 22 weeks PI and 12 weeks after treatment. The histopathological lesions were duct dilatation, mucosal hyperplasia, and periductal fibrosis, which progressed from 4 weeks to 22 weeks PI and even in treated rabbits. The dilated intrahepatic ducts over 1 mm diameter were detected by sonography. The present results indicate that sonographic findings are well correlated with histopathological lesions in rabbit clonorchiasis except for early phase of light burden of infection. The sonography has a limitation in discriminating residual sequelae of the ducts after praziquantel treatment.