이 작품은 학과 토목 및 환경 공학 어바나 샴페인 일리노이 대학에서 공학 대학 지원 되었다. 우리는 Kavya Mendu의 대학원 연구를 지원 하기 위한 Ravindra Kinra와 위베 Kinra 친목을 인정 합니다. 스캐닝 전자 현미경 조사 프레드릭 Seitz 소재 연구소와 일리노이 대학 어바나 샴페인에 베크만 연구소의 시설에서 실시 됐다.

참고: 여기서 설명 하는 프로토콜 일리노이 기관 동물 관리 및 사용 위원회의 동물 보호 지침을 따릅니다.
1. 견본 조달
<ol><li>미국 학과 농업 미국 농 무부 인증 도살에서에서 갓 수확된 소 화관을 수집 하 고 단단한 플라스틱 공기 냉각기 가방에 그들을 수송. 참고: 여기에 실시 하는 연구를 위해 화관 24-30 개월 오래 되 고, 옥수수, 무게 약 1000-1100 파운드 동물에서 수집 되었다.</li>
	<li>견본 준비 절차의 시작까지 -에서 화관 20 ° C를 고정 합니다. 이 온도 화관 신선한12,,1314를 유지합니다.</li>
</ol>2. 절단, 청소, 그리고는 견본을 포함
<ol><li>실 온에서 약 2 시간에 대 한 물 컨테이너에 냉동된 화관 녹여</li>
	<li>여러 개의 디스크에 대해 10-15 m m 두꺼운 외피 뼈의 균일 한 단면적으로 견본을 생산 하는 테이블 톱 다이아몬드 밴드 톱을 사용 하 여 중간 diaphysis 영역에서 잘라.</li>
	<li>해 부 키트를 사용 하 여 모든 연 조직 또는 외피 뼈에 연결 된 육체를 제거.</li>
	<li>잘라내기는 화관의 횡단면 단계 낮은 속도에 다이아몬드 wafering 블레이드를 사용 하 여 2.2에서에서 얻은 여러 약 cuboidal 섹션을 얻기 위해 뼈의 경도 축 젖은 조건에서 보았다. 참고: 여기, 견본 준비와 스크래치 테스트 수행-짧은에 경도 표본 설명. 그러나, 절단 방향 제외한 준비 절차 동일 가로 방향에 대 한 합니다.</li>
	<li>청소기 1.5% 음이온을 사용 하 여 준비 하는 솔루션에 표 백제 5% 표본 초음파 세탁 기술자에서 20 분 동안 청소.</li>
	<li>
아크릴 수 지에 외피 뼈의 견본을 포함 (여기 polymethyl 메타 크리 레이트 (PMMA)) 처리 및 안정성의 용이성에 대 한.
	<ol>
<li>표본 포함 하려면 먼저 릴리스 에이전트와 금형의 벽 코트. 다음 아크릴 수 지와 경화제 PMMA 제조 업체에 의해 주어진 지침에 의하여 비 커에서 혼합.</li>
		<li>긁힌 수 표면 각 금형에 장소 하나 잘라 외피 뼈 표본 아래쪽으로 직면 하 고. 아크릴 수 지 혼합물을 부 어에 견본 홀더를 준비. 표본 최대 4-5 h 동안 치료 하자.</li>
	</ol>
</li>
	<li>5-m m 두꺼운 디스크에 포함 된 표본을 잘라, 낮은 속도 사용 하 여 긁힌 수 표면 노출 보고 마운트 직경의 금속 (알루미늄) 디스크에 표본 34 m m, 높이 5mm cyanoacrylate 접착제를 사용 하 여.</li>
	<li>배어 있는 행 크 스 균형 염 분 솔루션 (HBSS) 계기에 있는 표본 랩과 추가 사용15,16까지 4 ° C에서 냉장 보관.</li>
</ol>3. 연 삭 및 연마 프로토콜
참고: 작은 길이 스케일에서 고 정밀도 테스트는 필수 표본 부드럽고 수평 표면입니다. 이전 프로토콜 연마13,17 측정에 상당한 부정확성으로 이어지는 큰 표면 거칠기에 결과. 낮은 평균 표면 거칠기, 100 미만 달성에 도전 있다 nm, 큰 지역 3 x 8 m m2 표면.
<ol><li>각각 사용 하 여 400 그 릿 및 600 모래 실리콘 카바 이드 논문 1 분 및 5 분, 실 온에서 소 외피 뼈 표본 갈기. 각각 100 rpm 및 150 rpm의 기본 속도에서 그 라인 더-폴 리 셔를 유지 합니다.</li>
	<li>기계는 각 단계에 대 일 분의 기간에 대 한 800의 그리고 1200 모래 종이에 상 온에서 소 외피 뼈 표본 갈기. 150 rpm, 60 rpm, 그리고 1 파운드의 부하 운영의 머리 속도의 기본 속도에서 그 라인 더-폴 리 셔를 유지 합니다.</li>
	<li>폴란드는 하드에 같은 순서로 3 µ m, 1 μ m, 및 0.25 µ m 다이아몬드 정지 솔루션을 사용 하 여 표본 구멍, 상 온에서 각각 90 분의 기간에 대 한 비 짠 옷감. 각각 기본 및 머리 속도 300 rpm 및 60 rpm, 폴 리 셔의 1 파운드에서 각 단계에 대 한 운영 부하를 유지 합니다.</li>
	<li>솔루션을 사용 하 0.05 µ m 알 루미나 정지 부드러운, 합성 주 천으로 100 rpm 및 60 rpm의 기지와 머리 속도 1 파운드에서 90 분 동안 각각, 또한 실 온에서 견본을 폴란드어.</li>
	<li>표본 드 이온된 수와 비 커에 넣어을 비 커에 연 삭, 연마 찌 꺼 기를 청소 하 여 교차 오염을 방지의 각 연속 단계 사이 2 분 동안 초음파 목욕.</li>
	<li>광학 현미경과 SEM 이미지를 사용 하 여 표면 기능 보기 참고: 시멘트 라인, Haversian 운하, osteons, 그림 1에서 같이, 중간 영역 및 격차 관찰 되었다 소 외피 뼈 표본에. 이러한 이미징 방법 공개 외피 뼈 표본의 다공성, 이기종, 및 이방성 특성. 또한, 고급 표면 검사는 표본의 광택된 표면 품질을 평가 하기 위해 수행 되었다. 대표 광택된 표면 그림 2에 표시 됩니다.</li>
</ol>4. 마이크로 스크래치 테스트
참고: 마이크로 스크래치 테스트 마이크로 스크래치 테스터 (그림 3)를 사용 하 여 광택된 소 외피 뼈 표본에 수행 됩니다. 다이아몬드 120 °의 200 µ m 및 정점 각도의 팁 반경과 록웰 indenter 연구에 사용 됩니다. 악기는 최대 30 명. 선형 진보적인 부하의 응용 프로그램을 수 있습니다. 또한, 악기 고정밀 센서 수평 부하, 침투 깊이 및 긁힘으로 인해 발생 하는 음향 방출 측정 장비 된다. 악기는 스크래치 홈의 파노라마를 캡처할 수 있습니다.
<ol><li>외피 뼈 표본 테스트 전에 참고 자료3폴 리 카보 네이트를 사용 하 여 로크 웰 indenter 팁 보정.</li>
	<li>무대에 외피 뼈 견본을 놓고 스크래치 테스트 마이크로 스크래치 테스터 모듈 통합 설정 광학 현미경을 사용 하 여 사이트를 선택 합니다.</li>
	<li>30 명. 30 mN 및 끝 부하의 시작 로드와 선형 진보적인 부하 적용 로딩 속도 60 N/min와 스크래치 길이 3 m m로 설정 합니다.</li>
	<li>수행 하는 일련의 스크래치 테스트는 짧은 경도 (그림 3b)에 소과 외피 뼈 표본 그림 3에서 볼 수 있듯이.</li>
	<li>그들이 충분 한지 체크 해 계속 모든 3 ~ 4 스크래치 테스트 집합 후 HBSS로 견본 표면에 젖은.</li>
	<li>2모델링 비선형 파괴 역학에 따라 스크래치 테스트 데이터를 분석 합니다.</li>
</ol>

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저자는 공개 없다.

마이크로 스크래치 테스트 유도 혼합 모드 골절3. 또한, 짧은 경도 소 외피 뼈 표본에서 골절 프로세스 프로브 세트 깊은 활성화 됩니다. 3 m m 긴 스크래치에 대 한 조사 프리즘 볼륨 이며 약 3, 600 µ m 긴, 600 µ m 폭, 480 µ m 깊이. 이 대용량 무 균된 응답 예측에 도움이. 비-선형 파괴 역학 모델 J에 따라 골절 저항 추출 있게-정수 계산1,,<sup cla...

이 연구에서 우리는 새로운 마이크로 스크래치 기법1,2,3,4,를 사용 하 여 눈금 (플레이트 수준)에 mesoscale (osteons)에서 소 조밀한 뼈의 골절 인 측정 5. 균열 개시와 균열 전파를 포함 하 여 뼈에 골절 프로세스 직접 길이 비늘 때문에 다른 구조상 성분 및 조직 계층의 다른 수준에 의해 좌우 된다. 따라서, 작은 길이 스케일에서 뼈 골절을 평가 뼈 취약성의 근본적인 이해를 양보 필수적 이다. 한편으로, 3-포인트 절곡 등 기존의 테스트 압축 긴장, 및 굴곡 테스트는 일반적으로 소과 대 퇴 골 및 경골 골절 특성화 거시적인 규모6,7, 에 대 한 실시 8. 다른 한편으로, 미세한 규모 파괴 인 성 측정, 하 비 커의 들여쓰기 골절 제안된9이었다. 마이크로 들여쓰기 방사형 균열을 생성 하는 비 커의 indenter를 사용 하 여 수행 되었다. 또한, 올리버 파 나노 분쇄 강인 성 방법 날카로운 큐브 코너 indenter10를 사용 하 여 수행 되었다.
위의 나노 기반 파괴 인 성 연구에 따라서 생성 된 균열의 길이 관찰자에 의해 측정 되었다 하 고 반 경험적 모델 파괴 인 성이 계산 하는 데 사용 되었다. 그러나, 이러한 메서드는 명료화, 주관적인, 그리고 결과 관찰자의 기술을 사용 하 여 광학 현미경 또는 전자 현미경을 스캐닝 균열 길이 측정 하는 필요 때문에 상당히 의존. 또한, 스크래치 테스트는 나노 스케일에서 실시 했다 하지만 기본 수학적 모델 아니다 물리학을 기반으로 강도 균열 때문에 감소에 대 한 고려 하지 않는 고 결함11. 따라서, 지식의 격차는 존재 한다: 물리학을 기반으로 기계적 모델을 기반으로 미세한 수준에서 골절 평가 하는 방법. 지식의이 갭 동기 돼지 표본5에 먼저 집중 하 여 뼈를 압축 하려면 마이크로 스크래치 테스트 응용 프로그램. 연구 이제 더 소 외피 뼈를 이해 하도록 확장 되었습니다.
표본의 2 개의 다른 방향 가능 하다: 경도 가로 및 세로. 세로 가로 골절 대 퇴 골의 종 축에 수직인 속성에 해당 합니다. 반면, 짧은 대 퇴 골5의 경도 축 골절 속성에 해당 하는 경도. 이 연구에서 우리는 스크래치 테스트 짧은 경도 방향에 있는 뼈의 골절 저항 하 소 외피 뼈를 적용 합니다.

<table>
	<tbody>
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			<td>Table Top Diamond Band Saw</td>
			<td>McMaster Carr, Elmhurst, IL</td>
			<td>Model&#160; C-40</td>
			<td>Blade speed of 40 mph; Blade dimensions: 37 inch in diameter, 0.02 inch wide and 0.14 inch deep</td>
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			<td>(Through) Grainger, Peoria, Illinois</td>
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			<td>Bransonic CPXH ultrasonic bath has a tank capacity of 2.5 gal</td>
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			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
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			<td>Anton Paar Switzerland AG</td>
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			<td>JEOL 6060LV general purpose scanning electron microscope</td>
			<td>JEOL USA, Inc., Peabody, MA</td>
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			<td>Environmental scanning electron microscope which enables imaging at low vacuum levels.</td>
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			<td>Philips XL30 ESEM FEG&#160;</td>
			<td>FEI Company</td>
			<td></td>
			<td>Wet mode working of the instrument enables imaging of non conductive samples without altering them&#160;</td>
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			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
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			<td>Consumables</td>
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			<td>Bovine Femur</td>
			<td>L&#38;M Slaughter house, Georgetown, IL</td>
			<td></td>
			<td>Corn fed, 24-30 month old mature bovine specimens.</td>
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			<td>Alconox Powdered Precision Cleaner</td>
			<td>Alconox, Inc., 30 Glenn St., Ste. 309, White Plains, NY, 10603</td>
			<td>1104-1</td>
			<td>Biodegradable, Non caustic, Interfering-residue free</td>
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			<td>Acrylic Plastic Casting</td>
			<td>Electron Microscopy Sciences</td>
			<td>24210-02</td>
			<td>Polymethyl Methacrylate</td>
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			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>36080400</td>
			<td>Grinding - Abrasive Papers</td>
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			<td>CarbiMet SiC Abrasive Paper 600 grit, 8 inch, PSA backed</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>36080600</td>
			<td>Grinding - Abrasive Papers</td>
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			<td>MicroCut Discs 800 grit, 8 inch, PSA backed</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>36080800</td>
			<td>Grinding - Abrasive Papers</td>
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		<tr>
			<td>MicroCut Discs 800 grit, 8 inch, PSA backed</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>16081200</td>
			<td>Grinding - Abrasive Papers</td>
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			<td>Texmet P For 8&#39;&#39; Wheel PSA</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>407638</td>
			<td>Polishing Cloth</td>
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			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>407518</td>
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			<td>Meta Di Supreme Polycrystalline Diamond Suspension, 3 &#181;m</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>406631</td>
			<td>Polishing suspension</td>
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			<td>Meta Di Supreme Polycrystalline Diamond Suspension, 1 &#181;m</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>406630</td>
			<td>Polishing suspension</td>
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			<td>Meta Di Supreme Polycrystalline Diamond Suspension, 0.25 &#181;m</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>406629</td>
			<td>Polishing suspension</td>
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			<td>MasterPrep Polishing Suspension, 0.05&#181;m</td>
			<td>Buehler,41 Waukegan Rd, Lake Bluff, IL 60044</td>
			<td>40-6377-032</td>
			<td>Polishing suspension</td>
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			<td>HBSS, calcium, magnesium, no phenol red</td>
			<td>Thermo Fisher Scientific</td>
			<td>14025126</td>
			<td>Buffer Solution</td>
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	</tbody>
</table>

fragility assessment of bovine cortical bone using scratch tests

뼈 조직의 5 가지 수준의 복잡 한 계층적 자료입니다. 노후화 같은 요인 및 질병 골다공증 같은 뼈, 골절 발생 하기 쉬운 그것을 만들기의 취약성 증가. 때문에 우리 사회에서 뼈 골절의 큰 사회 경제적 영향, 뼈의 각 계층 수준에의 기계적인 성능을 평가 하기 위해 새로운 방법을 필요가 있다. 강성과 강도 모든 비늘-나노, 마이크로, meso, 조사 수 있지만 거시적인-골절 평가 지금까지에 국한 거시적인 테스트. 이 제한 뼈 골절에 대 한 우리의 이해를 제한 하 고 실험실 및 임상 연구의 범위를 제한. 이 연구에서 우리는 비선형 파괴 역학과 결합 된 마이크로 스크래치 테스트를 사용 하 여 생체 길이 비늘에 있는 미세한에서 뼈의 분쇄 저항을 조사 합니다. 테스트는 소 외피 뼈 표본에 짧은 경도 방향에서 수행 됩니다. 세심 한 실험 프로토콜 개발 및 테스트의 많은 수 (102) 뼈 미세와 관련 된이 대 한 회계 동안 대뇌 피 질의 뼈 표본의 파괴 인 성 평가를 실시 하 고 있습니다.

원자 힘 현미경 검사 법은 광택된 표면 거칠기 측정에 사용 되었다. 엄지손가락의 규칙으로는 견본 표면 거칠기의 표면 기능 보다는 더 작은 크기 순서 인 경우 잘 닦 여 진된 것으로 평가가 없습니다. 이 경우에, 60의 측정 된 표면 거칠기 nm 40 µ m x 40 µ m 영역 명확 하 게이 조건 내에서 폭포.
그림 4 는 침?...

Watch this Scientific Journal Video about Fragility Assessment of Bovine Cortical Bone Using Scratch Tests at JoVE.com

Fragility Assessment of Bovine Cortical Bone Using Scratch Tests

스크래치 테스트를 사용 하 여 소 피 질 골의 취약성 평가

이 연구는 미세한 스크래치 테스트를 사용 하 여 하위 meso 수준 소 외피 뼈의 파괴 인 성을 평가 합니다. 이것은 원래, 목표, 엄격한, 그리고 거시적인 규모 아래 파괴 인 성이을 재현 방법 제안. 잠재적인 응용 프로그램 변화를 공부 하 고 골다공증 같은 질병으로 인해 뼈 취약성에 있다.

Bone is a complex hierarchical material with five distinct levels of organization. Factors like aging and diseases like osteoporosis increase the ...

fragility-assessment-of-bovine-cortical-bone-using-scratch-tests

Universidad de Cartagena UDEC

Research

JoVE Journal

Bioengineering

9.2K 조회수.  University of Illinois at Urbana Champaign. 이 연구는 미세한 스크래치 테스트를 사용 하 여 하위 meso 수준 소 외피 뼈의 파괴 인 성을 평가 합니다. 이것은 원래, 목표, 엄격한, 그리고 거시적인 규모 아래 파괴 인 성이을 재현 방법 제안. 잠재적인 응용 프로그램 변화를 공부 하 고 골다공증 같은 질병으로 인해 뼈 취약성에 있다.

비디오: Fragility Assessment of Bovine Cortical Bone Using Scratch Tests

Use of Human Perivascular Stem Cells for Bone Regeneration

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are a FACS-sorted population of 'pericytes' (CD146+CD34-CD45-) and 'adventitial cells' (CD146-CD34+CD45-), each of which we have previously reported to have properties of mesenchymal stem cells. PSCs, like MSCs, are able to undergo osteogenic differentiation, as well as secrete pro-osteogenic cytokines1,2. In the present protocol, we demonstrate the osteogenicity of PSCs in several animal models including a muscle pouch implantation in SCID (severe combined immunodeficient) mice, a SCID mouse calvarial defect and a femoral segmental defect (FSD) in athymic rats. The thigh muscle pouch model is used to assess ectopic bone formation. Calvarial defects are centered on the parietal bone and are standardly 4 mm in diameter (critically sized)8. FSDs are bicortical and are stabilized with a polyethylene bar and K-wires4. The FSD described is also a critical size defect, which does not significantly heal on its own4. In contrast, if stem cells or growth factors are added to the defect site, significant bone regeneration can be appreciated. The overall goal of PSC xenografting is to demonstrate the osteogenic capability of this cell type in both ectopic and orthotopic bone regeneration models.

Human perivascular stem cells (PSCs) are a novel stem cell class for skeletal tissue regeneration similar to mesenchymal stem cells (MSCs). PSCs can be isolated by FACS (fluorescence activated cell sorting) from adipose tissue procured during standard liposuction procedures, then combined with an osteoinductive scaffold to achieve bone formation in vivo.

뼈 재생을위한 인적 Perivascular 줄기 세포의 이용

Human perivascular stem cells (PSCs) can be isolated in sufficient numbers from multiple tissues for purposes of skeletal tissue engineering1-3. PSCs are ...

연구

생체공학

Preparation of Intact Bovine Tail Intervertebral Discs for Organ Culture

The intervertebral disc (IVD) is the joint of the spine connecting vertebra to vertebra. It functions to transmit loading of the spine and give flexibility to the spine. It composes of three compartments: the innermost nucleus pulposus (NP) encompassing by the annulus fibrosus (AF), and two cartilaginous endplates connecting the NP and AF to the vertebral body on both sides. Discogenic pain possibly caused by degenerative intervertebral disc disease (DDD) and disc herniations has been identified as a major problem in our modern society. To study possible mechanisms of IVD degeneration, in vitro organ culture systems with live disc cells are highly appealing. The in vitro culture of intact bovine coccygeal IVDs has advanced to a relevant model system, which allows the study of mechano-biological aspects in a well-controlled physiological and mechanical environment. Bovine tail IVDs can be obtained relatively easy in higher numbers and are very similar to the human lumbar IVDs with respect to cell density, cell population and dimensions. However, previous bovine caudal IVD harvesting techniques retaining cartilaginous endplates and bony endplates failed after 1-2 days of culture since the nutrition pathways were obviously blocked by clotted blood. IVDs are the biggest avascular organs, thus, the nutrients to the cells in the NP are solely dependent on diffusion via the capillary buds from the adjacent vertebral body. Presence of bone debris and clotted blood on the endplate surfaces can hinder nutrient diffusion into the center of the disc and compromise cell viability. Our group established a relatively quick protocol to "crack"-out the IVDs from the tail with a low risk for contamination. We are able to permeabilize the freshly-cut bony endplate surfaces by using a surgical jet lavage system, which removes the blood clots and cutting debris and very efficiently reopens the nutrition diffusion pathway to the center of the IVD. The presence of growth plates on both sides of the vertebral bone has to be avoided and to be removed prior to culture. In this video, we outline the crucial steps during preparation and demonstrate the key to a successful organ culture maintaining high cell viability for 14 days under free swelling culture. The culture time could be extended when appropriate mechanical environment can be maintained by using mechanical loading bioreactor. The technique demonstrated here can be extended to other animal species such as porcine, ovine and leporine caudal and lumbar IVD isolation.

This protocol illustrates a harvesting technique for coccygeal bovine intervertebral discs for organ culture for in vitro organ culture.

조직 문화에 대한 손상 소의 꼬리 척추 디스크의 준비

The intervertebral disc (IVD) is the joint of the spine connecting  vertebra to vertebra. It functions to transmit loading of the spine and give  ...

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that MicroCT provides quantitative high-resolution three-dimensional (3D) anatomical data non-destructively and longitudinally. Most importantly, with the development of a novel preclinical iodinated contrast agent called eXIA160, functional and metabolic assessment of the heart became possible. However, prior to the advent of commercial MicroCT scanners equipped with X-ray flat-panel detector technology and easy-to-use cardio-respiratory gating, preclinical studies of cardiovascular disease (CVD) in small animals required a MicroCT technologist with advanced skills, and thus were impractical for widespread implementation. The goal of this work is to provide a practical guide to the use of the high-speed Quantum FX MicroCT system for comprehensive determination of myocardial global and regional function along with assessment of myocardial perfusion, metabolism and viability in healthy mice and in a cardiac ischemia mouse model induced by permanent occlusion of the left anterior descending coronary artery (LAD).

In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

This method outlines the use of Quantum Micro-Computed Tomography (MicroCT) to assess cardiac morphology, function, perfusion, metabolism and viability with iodinated contrast agent in mice with experimentally-induced myocardial ischemia. The technique can be applied for non-destructive high-throughput longitudinal in vivo imaging of various animal models of human heart disease.

심근 구조, 기능의 생체 양적 평가에서 관류 및 생존 능력은 심장 마이크로 컴퓨터 단층 촬영을 사용하여

The use of Micro-Computed Tomography (MicroCT) for in vivo studies of small animals as models of human disease has risen tremendously due to the fact that ...

Modified Drop Tower Impact Tests for American Football Helmets

A modified National Operating Committee on Standards for Athletic Equipment (NOCSAE) test method for American football helmet drop impact test standards is presented that would provide better assessment of a helmet's on-field impact performance by including a faceguard on the helmet. In this study, a merger of faceguard and helmet test standards is proposed. The need for a more robust systematic approach to football helmet testing procedures is emphasized by comparing representative results of the Head Injury Criterion (HIC), Severity Index (SI), and peak acceleration values for different helmets at different helmet locations under modified NOCSAE standard drop tower tests. Essentially, these comparative drop test results revealed that the faceguard adds a stiffening kinematic constraint to the shell that lessens total energy absorption. The current NOCSAE standard test methods can be improved to represent on-field helmet hits by attaching the faceguards to helmets and by including two new helmet impact locations (Front Top and Front Top Boss). The reported football helmet test method gives a more accurate representation of a helmet's performance and its ability to mitigate on-field impacts while promoting safer football helmets.

This article provides a novel technique to assess the performance characteristics of American football helmets by inclusion of faceguards during NOCSAE Standard drop tests. Additionally, two more impact locations are proposed to be added to the NOCSAE certification.

미식 축구 헬멧에 대한 수정 드롭 탑 충격 테스트

A modified National Operating Committee on Standards for Athletic Equipment (NOCSAE) test method for American football helmet drop impact test standards ...

A Method to Estimate Cadaveric Femur Cortical Strains During Fracture Testing Using Digital Image Correlation

This protocol describes the method using digital image correlation to estimate cortical strain from high speed video images of the cadaveric femoral surface obtained from mechanical testing. This optical method requires a texture of many contrasting fiduciary marks on a solid white background for accurate tracking of surface deformation as loading is applied to the specimen. Immediately prior to testing, the surface of interest in the camera view is painted with a water-based white primer and allowed to dry for several minutes. Then, a black paint is speckled carefully over the white background with special consideration for the even size and shape of the droplets. Illumination is carefully designed and set such that there is optimal contrast of these marks while minimizing reflections through the use of filters. Images were obtained through high speed video capture at up to 12,000 frames/s. The key images prior to and including the fracture event are extracted and deformations are estimated between successive frames in carefully sized interrogation windows over a specified region of interest. These deformations are then used to compute surface strain temporally during the fracture test. The strain data is very useful for identifying fracture initiation within the femur, and for eventual validation of proximal femur fracture strength models derived from Quantitative Computed Tomography-based Finite Element Analysis (QCT/FEA).

In this protocol, the femur surface strains are estimated during fracture testing using the digital image correlation technique. The novelty of the method involves application of a high-contrast stochastic speckle pattern on the femur surface, carefully specified illumination, high speed video capture, and digital image correlation analysis for strain calculations.

방법 골절 디지털 이미지 상관 관계를 사용 하 여 테스트 하는 동안 싱가포르로 대 퇴 골 피 질 긴장을 예상

This protocol describes the method using digital image correlation to estimate cortical strain from high speed video images of the cadaveric femoral ...

Biological Compatibility Profile on Biomaterials for Bone Regeneration

Large non-union bone fractures are a significant challenge in orthopedic surgery. Although auto- and allogeneic bone grafts are excellent for healing such lesions, there are potential complications with their use. Thus, material scientists are developing synthetic, biocompatible biomaterials to overcome these problems. In this study, we present a multidisciplinary platform for evaluating biomaterials for bone repair. We combined expertise from bone biology and immunology to develop a platform including in vitro osteoclast (OC) and osteoblast (OB) assays and in vivo mouse models of bone repair, immunogenicity, and allergenicity. We demonstrate how to perform the experiments, summarize the results, and report on biomaterial biocompatibility. In particular, we tested OB viability, differentiation, and mineralization and OC viability and differentiation in the context of &#946;-tricalcium phosphate (&#946;-TCP) disks. We also tested a &#946;-TCP/Collagen (&#946;-TCP/C) foam which is a commercially available material used clinically for bone repair in a critical-sized calvarial bone defect mouse model to determine the effects on the early phase of bone healing. In parallel experiments, we evaluated immune and allergic responses in mice. Our approach generates a biological compatibility profile of a bone biomaterial with a range of parameters necessary for predicting the biocompatibility of biomaterials used for bone healing and repair in patients.

The number of novel biomaterials engineered for repairing large bone lesions is continuously expanding with the aim to enhance bone healing and overcome the complications associated with bone transplantation. Here, we present a multidisciplinary strategy for pre-clinical biocompatibility testing of biomaterials for bone repair.

뼈 재생을 위해 생체에서 생물학적 호환성 프로필

Large non-union bone fractures are a significant challenge in orthopedic surgery. Although auto- and allogeneic bone grafts are excellent for healing such ...

Calvarial Model of Bone Augmentation in Rabbit for Assessment of Bone Growth and Neovascularization in Bone Substitution Materials

The basic principle of the rabbit calvarial model is to grow new bone tissue vertically on top of the cortical part of the skull. This model allows assessment of bone substitution materials for oral and craniofacial bone regeneration in terms of bone growth and neovascularization support. Once animals are anesthetized and ventilated (endotracheal intubation), four cylinders made of polyether ether ketone (PEEK) are screwed onto the skull, on both sides of the median and coronal sutures. Five intramedullary holes are drilled within the bone area delimited by each cylinder, allowing influx of bone marrow cells. The material samples are placed into the cylinders which are then closed. Finally, the surgical site is sutured, and animals are awaken. Bone growth may be assessed on live animals by using microtomography. Once animals are euthanized, bone growth and neovascularization may be evaluated by using microtomography, immune-histology and immunofluorescence. As the evaluation of a material requires maximum standardization and calibration, the calvarial model appears ideal. Access is very easy, calibration and standardization are facilitated by the use of defined cylinders and four samples may be assessed simultaneously. Furthermore, live tomography may be used and ultimately a large decrease in animals to be euthanized may be anticipated.

Here we present a surgical protocol in rabbits with the aim to assess bone substitution materials in terms of bone regeneration capacities. By using PEEK cylinders fixed onto rabbit skulls, osteoconduction, osteoinduction, osteogenesis and vasculogenesis induced by the materials may be evaluated either on live or euthanized animals.

The basic principle of the rabbit calvarial model is to grow new bone tissue vertically on top of the cortical part of the skull. This model allows ...

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Biplane videoradiography can quantify shoulder kinematics with a high degree of accuracy. The protocol described herein was specifically designed to track the scapula, humerus, and the ribs during planar humeral elevation, and outlines the procedures for data collection, processing, and analysis. Unique considerations for data collection are also described.

바이플러나 비디오 방사선 촬영을 사용하여 3D 생체 내 어깨 운동학 측정

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, ...

3D Bioprinting of Murine Cortical Astrocytes for Engineering Neural-Like Tissue

Astrocytes are glial cells with an essential role in the central nervous system (CNS), including neuronal support and functionality. These cells also respond to neural injuries and act to protect the tissue from degenerative events. In vitro studies of astrocytes&#39; functionality are important to elucidate the mechanisms involved in such events and contribute to developing therapies to treat neurological disorders. This protocol describes a method to biofabricate a neural-like tissue structure rich in astrocytes by 3D bioprinting astrocytes-laden bioink. An extrusion-based 3D bioprinter was used in this work, and astrocytes were extracted from C57Bl/6 mice pups&#39; brain cortices. The bioink was prepared by mixing cortical astrocytes from up to passage 3 to a biomaterial solution composed of gelatin, gelatin-methacryloyl (GelMA), and fibrinogen, supplemented with laminin, which presented optimal bioprinting conditions. The 3D bioprinting conditions minimized cell stress, contributing to the high viability of the astrocytes during the process, in which 74.08% &#177; 1.33% of cells were viable right after bioprinting. After 1 week of incubation, the viability of astrocytes significantly increased to 83.54% &#177; 3.00%, indicating that the 3D construct represents a suitable microenvironment for cell growth. The biomaterial composition allowed cell attachment and stimulated astrocytic behavior, with cells expressing the specific astrocytes marker glial fibrillary acidic protein (GFAP) and possessing typical astrocytic morphology. This&#160;reproducible protocol provides a valuable method to biofabricate 3D neural-like tissue rich in astrocytes that resembles cells&#39; native microenvironment, useful to researchers that aim to understand astrocytes&#39; functionality and their relation to the mechanisms involved in neurological diseases.

Here we report a method of 3D bioprinting murine cortical astrocytes for biofabricating neural-like tissues to study the functionality of astrocytes in the central nervous system and the mechanisms involving glial cells in neurological diseases and treatments.

신경과 같은 조직을 위한 Murine 피질 성상 세포의 3D 생물 인쇄

Astrocytes are glial cells with an essential role in the central nervous system (CNS), including neuronal support and functionality. These cells also ...

3D Co-Culture Assay: 암 약물 스크리닝을 위한 혈관화된 골형성 틈새

Simple Establishment of a Vascularized Osteogenic Bone Marrow Niche Using Pre-Cast Poly(ethylene Glycol) (PEG) Hydrogels in an Imaging Microplate

The bone and bone marrow are highly vascularized and structurally complex organs, and are sites for cancer and metastasis formation. In vitro models recapitulating bone- and bone marrow-specific functions, including vascularization, that are compatible with drug screening are highly desirable. Such models can bridge the gap between simplistic, structurally irrelevant two-dimensional (2D) in vitro models and the more expensive, ethically challenging in vivo models. This article describes a controllable three-dimensional (3D) co-culture assay based on engineered poly(ethylene glycol) (PEG) matrices for the generation of vascularized, osteogenic bone-marrow niches. The PEG matrix design allows the development of 3D cell cultures through a simple cell seeding step requiring no encapsulation, thus enabling the development of complex co-culture systems. Furthermore, the matrices are transparent and pre-cast onto glass-bottom 96-well imaging plates, rendering the system suitable for microscopy. For the assay described here, human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) are cultured first until a sufficiently developed 3D cell network is formed. Subsequently, GFP-expressing human umbilical vein endothelial cells (HUVECs) are added. The culture development is followed by bright-field and fluorescence microscopy. The presence of the hBM-MSC network supports the formation of vascular-like structures that otherwise&#160;would not form and that remain stable for at least 7 days. The extent of vascular-like network formation can easily be quantified. This model can be tuned toward an osteogenic bone-marrow niche by supplementing the culture medium with bone morphogenetic protein 2 (BMP-2), which promotes the osteogenic differentiation of the hBM-MSCs, as assessed by increased alkaline phosphatase (ALP) activity at day 4 and day 7 of co-culture. This cellular model can be used as a platform for culturing various cancer cells and studying how they interact with bone- and bone marrow-specific vascular niches. Moreover, it is suitable for automation and high-content analyses, meaning it would enable cancer drug screening under highly reproducible culture conditions.

저자 스포트라이트: 이미징 마이크로플레이트에서 프리캐스트 폴리(에틸렌 글리콜)(PEG) 하이드로겔을 사용하여 혈관화된 골형성 골수 틈새의 간단한 확립  

An in vitro model of the bone marrow vascular niche is established by seeding mesenchymal and endothelial cells onto pre-cast 3D PEG hydrogels. The endothelial networks, ECM components, and ALP activity of the niches vary depending on the growth factor used. The platform can be used for advanced cancer models.

이미징 마이크로플레이트에서 프리캐스트 폴리(에틸렌 글리콜)(PEG) 하이드로겔을 사용하여 혈관화된 골수 틈새의 간단한 설정

The bone and bone marrow are highly vascularized and structurally complex organs, and are sites for cancer and metastasis formation. In vitro models ...