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1.
J. appl. oral sci ; 27: e20180103, 2019. graf
Article in English | LILACS, BBO | ID: biblio-1002400

ABSTRACT

Abstract Objective This study aimed to evaluate the inflammatory effect and bone formation in sterile surgical failures after implantation of a collagen sponge with mesenchymal stem cells from human dental pulp (hDPSCs) and Aloe vera. Material and Methods Rattus norvegicus (n=75) were divided into five experimental groups according to treatment: G1) control (blood clot); G2) Hemospon®; G3) Hemospon® in a culture medium enriched with 8% Aloe vera; G4) Hemospon® in a culture medium containing hDPSCs and G5) Hemospon® in a culture medium enriched with 8% Aloe vera and hDPSCs. On days 7, 15 and 30, the animals were euthanized, and the tibia was dissected for histological, immunohistochemistry and immunofluorescence analyses. The results were analyzed using nonparametric Kruskal-Wallis test and Dunn's post-test. Results On days 7 and 15, the groups with Aloe vera had less average acute inflammatory infiltrate compared to the control group and the group with Hemospon® (p<0.05). No statistically significant difference was found between the groups regarding bone formation at the three experimental points in time. Osteopontin expression corroborated the intensity of bone formation. Fluorescence microscopy revealed positive labeling with Q-Tracker® in hDPSCs before transplantation and tissue repair. Conclusion The results suggest that the combination of Hemospon®, Aloe vera and hDPSCs is a form of clinical treatment for the repair of non-critical bone defects that reduces the inflammatory cascade's effects.


Subject(s)
Humans , Animals , Male , Rats , Bone Regeneration/drug effects , Bone Regeneration/physiology , Plant Extracts/pharmacology , Dental Pulp/cytology , Mesenchymal Stem Cell Transplantation/methods , Aloe/chemistry , Osteogenesis/drug effects , Osteogenesis/physiology , Tibia/drug effects , Tibia/physiology , Tibia/pathology , Time Factors , Immunohistochemistry , Hemostatics/pharmacology , Cell Survival/drug effects , Cell Survival/physiology , Cells, Cultured , Reproducibility of Results , Collagen/pharmacology , Treatment Outcome , Osteopontin/analysis , Flow Cytometry , Microscopy, Fluorescence
2.
Acta cir. bras ; 33(4): 324-332, Apr. 2018. tab, graf
Article in English | LILACS | ID: biblio-886287

ABSTRACT

Abstract Purpose: To investigate if the inorganic bovine bone matrix changes the bone formation in rats submitted to inhalation of cigarette smoke. Methods: Twenty Wistar rats were divided into two groups: Cigarette Clot Group (CCG), which in the inhalation chamber received the smoke of 10 cigarettes, 3 times a day, 10 minutes, for 30 days and had the surgical cavity filled by clot; Cigarette Biomaterial Group (CBG), submitted to the same inhalation technique but with the cavity filled by biomaterial. Results: In CCG there was a significant difference of new bone tissue in the analyzed periods (15 and 45 days), and in 15 days, there was 4.8 ± 0.42 of bone formed and 11.73 ± 0.59 (p <0.05) in 45 days. The CBG also showed a significant difference between the periods of 15 to 45 days, being respectively 6.16 ± 0.30 and 11.60 ± 0.61. However, when the groups were compared, within the same analyzed periods, a significant difference was observed only in the period of 15 days, with the new bone percentage being greater in the CBG. Conclusion: The bone matrix acted as an osteoinductive biomaterial, biocompatible and aided in the repair process, mainly in the initial period of recovery.


Subject(s)
Animals , Male , Bone Regeneration/drug effects , Bone Regeneration/physiology , Bone Substitutes/pharmacology , Cigarette Smoking/adverse effects , Osteogenesis/drug effects , Osteogenesis/physiology , Tibia/surgery , Tibia/drug effects , Tibia/physiology , Time Factors , Cattle , Random Allocation , Reproducibility of Results , Bone Transplantation/methods , Treatment Outcome , Rats, Wistar , Inhalation Exposure/adverse effects , Heterografts/physiology
3.
Braz. j. med. biol. res ; 49(3): e5086, Mar. 2016. tab, graf
Article in English | LILACS | ID: lil-771934

ABSTRACT

High-impact exercise has been considered an important method for treating bone loss in osteopenic experimental models. In this study, we investigated the effects of osteopenia caused by inactivity in femora and tibiae of rats subjected to jump training using the rat tail suspension model. Eight-week-old female Wistar rats were divided into five groups (n=10 each group): jump training for 2 weeks before suspension and training during 3 weeks of suspension; jump training for 2 weeks before suspension; jump training only during suspension; suspension without any training; and a control group. The exercise protocol consisted of 20 jumps/day, 5 days/week, with a jump height of 40 cm. The bone mineral density of the femora and tibiae was measured by double energy X-ray absorptiometry and the same bones were evaluated by mechanical tests. Bone microarchitecture was evaluated by scanning electron microscopy. One-way ANOVA was used to compare groups. Significance was determined as P<0.05. Regarding bone mineral density, mechanical properties and bone microarchitecture, the beneficial effects were greater in the bones of animals subjected to pre-suspension training and subsequently to training during suspension, compared with the bones of animals subjected to pre-suspension training or to training during suspension. Our results indicate that a period of high impact exercise prior to tail suspension in rats can prevent the installation of osteopenia if there is also training during the tail suspension.


Subject(s)
Animals , Female , Bone Diseases, Metabolic/prevention & control , Hindlimb Suspension/physiology , Physical Conditioning, Animal/physiology , Biomechanical Phenomena/physiology , Bone Density/physiology , Cancellous Bone/pathology , Femur/pathology , Femur/physiology , Hindlimb Suspension/adverse effects , Models, Animal , Rats, Wistar , Tibia/pathology , Tibia/physiology
4.
Bauru; s.n; 2016. 173 p. tab, ilus.
Thesis in Portuguese | LILACS, BBO | ID: biblio-881977

ABSTRACT

O presente estudo teve como objetivo avaliar a resposta biológica ao redor de implantes de titânio grau IV (titânio comercialmente puro) e grau V (Ti6Al4V), com diferentes tipos de tratamentos de superfície através da análise do contato ossoimplante (bone implant contact - BIC) e da área de neoformação óssea com e sem fluorocromo (bone area BA e BAfluo) das 3 primeiras roscas em contato ósseo de cada implante. Para isso, utilizou-se um total de 90 implantes Cone Morse de titânio grau IV (Drive 45 implantes) e titânio grau V (Facility 45 implantes), com dimensões de 3.5x8mm e 2.9x7mm, respectivamente. Estes dois tipos de implantes foram avaliados em três tratamentos de superfícies diferentes: a) superfície com jateamento com partículas abrasivas seguido de tratamento ácido - NeoPoros (NP) - em embalagem seca (Grupo Controle); b) superfície jateada seguido de tratamento ácido e energia de superfície, armazenado em líquido (ESm); c) superfície jateada seguido de tratamento ácido com energia de superfície e embalado a seco (ESs); totalizando 6 grupos, distribuídos em 15 coelhos New Zealand, em cada um foram instalados 6 implantes, sendo 3 em cada tíbia. Após 15 dias de osseointegração, os coelhos passaram por eutanásia e as tíbias seccionadas, fixadas e incluídas para a avaliação histológica e histomorfométrica. Mensurações no analisador de imagens ImageJ foram realizadas e a análise dos dados estatísticos, de todos os grupos foram avaliados através da análise de variância a dois critérios e do teste de Tukey para comparações múltiplas grupo a grupo, adotando o nível de significância de 5% (p<0,05). Os resultados mostraram que não houve diferença estatisticamente significante entre os dois tipos de titânio, porém houve diferença estatisticamente significante entre os tipos de superfície em relação ao BIC, BA e BAfluo; também, não houve interação entre titânio e superfície. Na análise do contato osso-implante (BIC) a superfície ESm teve melhor desempenho em relação ao NP, que por sua vez foi semelhante ao ESs. Quanto à área óssea (BA), a superfície NP teve menor desempenho em relação à ESs, este obteve semelhante desempenho a ESm. Quanto a área ósseo neoformada com presença de fluorocromo (BAfluo), NP teve menor desempenho em relação ao ESs, o qual obteve semelhante comportamento a ESm. Com isso, concluiu-se que implantes de titânio de gau IV e grau V obtiveram respostas biológicas equivalentes, enquanto que a energia de superfície com a molhabilidade podem ser consideradas como vantagem, uma vez que otimizam o processo de osseointegração.(AU)


This study aimed to evaluate the biological response around grade IV (commercially pure titanium) and grade V (Ti6Al4V) titanium implants with different types of surface treatments by analyzing bone-implant contact (BIC) and the bone formation area with and without fluorochrome (BA and BAfluo) of the 3 first threads on bone contact of each implant. To this end, this study used 90 Morse Taper grade IV (Drive - 45 implants) and grade V (Facility - 45 implants) titanium implants, measuring 3.5x8mm and 2.9x7mm, respectively. Both types of implants were evaluated in three different surface treatments: a) blasted/acid-etched implant surface - NeoPoros (NP) - dry pack (control group); b) blasted/acid-etched implant surface and surface energy, stored in liquid (ESm); c) blasted/acid-etched implant surface with surface energy and dry packed (ESs); totalizing 6 groups, distributed in 15 New Zealand rabbits. Six implants were placed in each rabbit, 3 in each tibia. After 15 days of osseointegration, the rabbits were euthanized and the tibias sectioned, fixed and embedded for histologic and histomorphometric evaluation. Measurements were carried out using the image analysis program ImageJ and the assessment of statistical data concerning all groups was done through the two-way analysis of variance and the Tukey test for multiple comparisons group to group, adopting the significance level of 5% ( p <0.05). The results showed no statistically significant difference between the types of titanium used. However, there were statistically significant differences between the types of surface in relation to the BIC, BA and BAfluo. In addition, there was no interaction between titanium and the surface. Concerning the analysis of bone-implant contact (BIC), the ESm surface had better performance compared to the NP, which, in turn, was similar to the ESs. As for bone area (BA), the NP surface had lower performance in relation to the ESs surface, as the latter had a similar performance to the ESm surface. Concerning the newly formed bone area with presence of fluorochrome (BAfluo), the NP had lower performance if compared to the ESs, which behaved similarly to that of the ESm surface. Thus, this study concluded that grade IV and grade V titanium implants showed equivalent biological responses, while the surface energy, together with its wettability, can be considered an advantage, enhancing the osseointegration process.(AU)


Subject(s)
Humans , Male , Rabbits , Bone Regeneration/physiology , Bone-Implant Interface/physiology , Titanium/chemistry , Titanium/therapeutic use , Dental Implantation, Endosseous/methods , Reproducibility of Results , Surface Properties , Tibia/physiology , Tibia/surgery , Treatment Outcome
5.
Clinics in Orthopedic Surgery ; : 49-56, 2016.
Article in English | WPRIM | ID: wpr-101615

ABSTRACT

BACKGROUND: Degenerative osteoarthritis of the knee usually shows arthritic change in the medial tibiofemoral joint with severe varus deformity. In total knee arthroplasty (TKA), the medial release technique is often used for achieving mediolateral balancing. But, in a more severe varus knee, there are more difficult technical problems. Bony resection of the medial proximal tibia (MPT) as an alternative technique for achieving soft tissue balancing was assessed in terms of its effectiveness and possibility of quantification. METHODS: TKAs were performed in 78 knees (60 patients) with vertical bone resection of the MPT for soft tissue balancing from September 2011 to March 2013. During operation, the medial and lateral gaps were measured before and after the bony resection technique. First, the correlation between the measured thickness of the resected bone and the change in medial and lateral gaps was analyzed. Second, the possibility of quantification of each parameter was evaluated by linear regression and the coefficient ratio was obtained. RESULTS: A significant correlation was identified between alteration in the medial gap change in extension and the measured thickness of the vertically resected MPT (r = 0.695, p = 0.000). In the medial gap change in flexion, there was no statistical significance (r = 0.214, p = 0.059). When the MPT was resected at an average thickness of 8.25 +/- 1.92 mm, the medial gap in extension was increased by 2.94 +/- 0.87 mm. In simple linear regression, it was predictable that MPT resection at a thickness of 2.80 mm was required to increase the medial gap by 1.00 mm in knee extension. CONCLUSIONS: The method of bone resection of the MPT can be considered effective with a predictable result for achieving soft tissue balancing in terms of quantification during TKA.


Subject(s)
Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Arthroplasty, Replacement, Knee/methods , Knee/physiology , Osteoarthritis, Knee/surgery , Tibia/physiology
6.
Clinics ; 68(9): 1180-1188, set. 2013. tab, graf
Article in English | LILACS | ID: lil-687765

ABSTRACT

OBJECTIVE: This study provides an experimental and finite element analysis of knee-joint structure during extended-knee landing based on the extracted impact force, and it numerically identifies the contact pressure, stress distribution and possibility of bone-to-bone contact when a subject lands from a safe height. METHODS: The impact time and loads were measured via inverse dynamic analysis of free landing without knee flexion from three different heights (25, 50 and 75 cm), using five subjects with an average body mass index of 18.8. Three-dimensional data were developed from computed tomography scans and were reprocessed with modeling software before being imported and analyzed by finite element analysis software. The whole leg was considered to be a fixed middle-hinged structure, while impact loads were applied to the femur in an upward direction. RESULTS: Straight landing exerted an enormous amount of pressure on the knee joint as a result of the body's inability to utilize the lower extremity muscles, thereby maximizing the threat of injury when the load exceeds the height-safety threshold. CONCLUSIONS: The researchers conclude that extended-knee landing results in serious deformation of the meniscus and cartilage and increases the risk of bone-to-bone contact and serious knee injury when the load exceeds the threshold safety height. This risk is considerably greater than the risk of injury associated with walking downhill or flexion landing activities. .


Subject(s)
Adult , Female , Humans , Male , Young Adult , Finite Element Analysis , Knee Joint/physiology , Movement/physiology , Anterior Cruciate Ligament/physiology , Biomechanical Phenomena/physiology , Femur/physiology , Imaging, Three-Dimensional , Knee Injuries/physiopathology , Knee Joint/anatomy & histology , Medical Illustration , Pressure , Reference Values , Risk Factors , Range of Motion, Articular/physiology , Stress, Mechanical , Time Factors , Tibia/physiology , Weight-Bearing/physiology
7.
Int. j. morphol ; 31(2): 562-569, jun. 2013. ilus
Article in Spanish | LILACS | ID: lil-687102

ABSTRACT

El propósito del presente trabajo es brindar información acerca de las propiedades biomecánicas y morfológicas de la tibia de perro sometida a cargas dinámicas. Los objetivos fueron evaluar la resistencia de la tibia frente al impacto mediante el Método de Ensayo Charpy, relacionar la misma con el área total, el área cortical y el área de la cavidad medular del hueso, comparándola entre talla, edad y sexo diferente. La importancia clínica, ortopédica y quirúrgica que reviste la región de la pierna del perro fundamenta esta investigación. Se utilizaron tibias de perro en condiciones aisladas, extraídas postmortem de 30 animales mestizos adultos jóvenes provenientes del servicio de zoonosis de la ciudad de Río Cuarto. Se determinó en la tibia derecha e izquierda: peso y longitud total del hueso, diámetros cráneo-caudal y latero-medial en la mitad de la diáfisis. A la tibia izquierda se le practicó osteotomía transversal en la mitad de su diáfisis. En la superficie de sección se midió: espesor de la cortical, diámetro medular y se obtuvo el área de sección total, área cortical y área medular. La tibia derecha fue sometida al Método de Ensayo Charpy. Se realizó el análisis estadístico correspondiente. La resistencia del hueso presentó una correlación de r=0,70 (p= 0,000019); r=0,67 (p=0,000059) y r=0,29 (p=0,12) con respecto a las áreas cortical, total y medular respectivamente. La morfología tiene influencia sobre las propiedades biomecánicas del hueso. A medida que aumenta el área cortical aumenta la energía de impacto absorbida. En cambio, a mayor área de cavidad medular la energía de impacto absorbida aumenta pero en menor magnitud. Existen diferencias estadísticamente significativas (p=0,0168) entre la talla del animal y la resistencia de la tibia. La edad (p=0,73) y el sexo (p=0,18) no presentaron influencias significativas sobre las propiedades biomecánicas de la tibia.


The purpose of this work is to provide information about biomechanical and morphological properties of the dog tibia bone subject to dynamic loads. The objectives were: evaluate the resistance of the tibia subject impact used Charpy test Method; linking it with total area, cortical area and bone marrow cavity; and compare it with weight, age and sex categories. The clinical, orthopedical and surgical relevance of the dog leg region is the basis for this research. Dog tibia were used in isolated conditions, removed postmortem from 30 adult animals defined raceless, from the zoonoses service of the city of Río Cuarto. Weight and total bone length, cranial-caudal and lateral-medial diameter in the middle of the diaphysis, were determined in the left and right tibia. The left tibia was osteotomized transversely in the middle of the diaphysis. On the surface section we measured: cortical thickness, diameter of the bone marrow cavity, and obtained the total section area, cortical area and medullary area. The right tibia was subjected to Charpy test method. Statistical analysis was performed accordingly. The bone strength showed a correlation of r=0.70 (p= 0.000019); r=0.67 (p=0.000059) and r=0.29 (p=0.12) with respect to the cortical area, total area and medullary area respectively. The morphology has influence on the biomechanical properties of bone, with increasing cortical area increases the impact energy absorbed. In contrast, a greater area of the medullary cavity of impact energy absorbed increases but to a lesser magnitude. There were statistically significant differences (p=0.0168) of size on the strength of the tibia. Age (p=0.7343) and sex (p=0.1898) had no significant influence on the biomechanical properties of the tibia.


Subject(s)
Animals , Tibia/anatomy & histology , Tibia/physiology , Biomechanical Phenomena , Dogs , Stress, Mechanical
8.
Acta cir. bras ; 26(6): 475-480, Nov.-Dec. 2011. ilus, tab
Article in English | LILACS | ID: lil-604197

ABSTRACT

PURPOSE: Comparing the ionizing radiation effects on bone neoformation of rats tibiae previously submitted to radiotherapy with a single dosage of 30Gy with the contralateral tibiae that have received secondary radiation. METHODS: In thirty male Wistar rats, 30 days before surgical procedure when round defects would be created on the bone, the right tibia was irradiated with 30Gy and the left tibia received a calculated secondary radiation dose of 7Gy. Sacrifices were performed after 4, 7, 14, 21, 56 and 84 postoperative days and both tibiae were removed for histological processing. RESULTS: The left tibiae that received the dose of 7Gy has shown more bone neoformation from 14th postoperative days, giving evidences of less damage to cellular population responsible by bone neoformation. On the other hand, the dose of 30Gyon right tibiae did not exhibit significant differences among the periods, suggesting damage of long-lasting or even permanent duration. CONCLUSION: Tibiae submitted to radiation dose of 30Gy have shown more damage to bone cells than tibiae that received secondary radiation dose of 7Gy, especially observed on 14th, 56th and 84th postoperative days.


OBJETIVO: Comparar os efeitos da radiação ionizante na reparação óssea em tíbias de ratos, submetidas à radioterapia prévia com doses 30Gy, com as tíbias contralaterais que receberam radiação secundária. MÉTODOS: No total, 30 ratos Wistar machos foram submetidos à cirurgia para realização de defeitos circulares em ambas as tíbias de cada rato, com radioterapia prévia de 30 dias, sendo que a tíbia direita recebeu a dose de 30Gy e tíbia esquerda a dose de radiação secundária calculada em 7Gy. Os sacrifícios ocorreram em 4, 7, 14, 21, 56 e 84 dias da realização do defeito ósseo e as tíbias foram removidas para processamento histológico. RESULTADOS: O grupo de 7Gy apresentou maior neoformação a partir do período de 14 dias, indicando pouco dano aos elementos celulares responsáveis pela reparação óssea, enquanto que o grupo de 30Gy não apresentou diferenças significantes entre os períodos, sugerindo um dano de efeito prolongado ou até mesmo permanente. CONCLUSÃO: As tíbias irradiadas com 30Gy apresentaram maior dano às células ósseas do que as tíbias que receberam radiação secundária de 7Gy, principalmente observadas nos períodos de 14, 56 e 84 dias.


Subject(s)
Animals , Male , Rats , Bone Regeneration/radiation effects , Radiation Injuries, Experimental/pathology , Tibia/radiation effects , Tibial Fractures/radiotherapy , Disease Models, Animal , Dose-Response Relationship, Radiation , Radiation Dosage , Rats, Wistar , Radiation Injuries, Experimental/physiopathology , Tibia/physiology , Tibial Fractures/pathology
9.
Journal of Dental School-Shahid Beheshti University of Medical Sciences. 2010; 28 (4): 219-224
in Persian | IMEMR | ID: emr-143863

ABSTRACT

Gonadal hormones have effect on the growth through increasing the osteoblastic activity of bone. They have influence on the calcium metabolism and therefore, are influential on the calcium level of serum and the strength of the bones. The purpose of this study is to examine the effects of gonadal hormones deficiency on the percentage of bone calcium of the tibia in rats. In the present experimental study 50 thirty - day - old Wistar rats comprised the sample. 25 male rats were randomly divided into 2 groups: Experimental group, i.e. orchidectomy ORX, [n=15] and control group, sham- operation, [n=10] and also 25 female rats were divided in the same way into 2 groups: Experimental group, i.e. ovariectomy OVX, [n=15] and control group, sham- operation, [n=10]. Samples were sacrificed 6 months after the surgery i.e. orchidectomies, ovariectomies, and sham operations. Percentage of bone calcium was determined by atomic absorption spectrophotometry. Serum testosterone, progesterone and estradiol levels were measured by ELISA. Serum testosterone level significantly decreased in the ORX group as compared with the male sham- operated group. In this study estradiol level was not changed in OVX group, but despite the significant decrease in progesterone level [p<0.001], no significant differences in all variables were found between the OVX group and female sham- operated group. In the ORX group, body length and weight, were significantly smaller than in the male sham- operated group. No significant difference in bone calcium percentage was found [Student's t-test] between control and experimental groups. In conclusion, it seems that the suppression of gonadal hormones secretion in the growth phase cannot decrease calcium percentage of tibia bone in rats


Subject(s)
Animals, Laboratory , Tibia/physiology , Tibia/metabolism , Calcium , Rats, Wistar , Spectrophotometry, Atomic
10.
Int. j. morphol ; 26(4): 1053-1058, Dec. 2008. ilus, tab
Article in English | LILACS | ID: lil-532938

ABSTRACT

The aim of this study was to investigate the effect of high fat diet and different frequencies of swimming programs in the tibial anterior muscle in male Wistar rats. In conclusion, the aerobic training during two days/week and five days/week caused injuries in muscle fibers and the high fat diet did not cause statically significant results compared to normal diet.


El objetivo de este estudio fue investigar el efecto de dietas ricas en grasas y diferentes frecuencias de natación, en el músculo tibial anterior, de ratas machos Wistar. El entrenamiento aeróbico, durante dos y cinco días por semana, causó lesiones en las fibras musculares y la dieta alta en grasa, no produjo resultados estadísticamente significativos, en comparación con la dieta normal.


Subject(s)
Male , Animals , Rats , Dietary Fats , Muscle, Skeletal/anatomy & histology , Muscle, Skeletal/metabolism , Swimming/physiology , Oxygen Consumption/physiology , Exercise/physiology , Muscle, Skeletal/physiology , Rats, Wistar , Tibia/anatomy & histology , Tibia/physiology
11.
Braz. oral res ; 19(1): 47-51, Jan.-Mar. 2005. ilus, graf
Article in English | LILACS | ID: lil-403734

ABSTRACT

O objetivo deste estudo foi avaliar a influência da inalação da fumaça de cigarro (IFC) e o efeito de sua interrupção na qualidade óssea da tíbia. Quarenta e um ratos Wistar machos foram aleatoriamente designados a um dos seguintes grupos: Grupo 1 – controle (n = 14), Grupo 2 – 3 meses de IFC e 2 meses sem exposição à fumaça (n = 12) e Grupo 3 – 5 meses de IFC (n = 15). Ao final do período experimental, os animais foram sacrificados, as tíbias removidas e imediatamente radiografadas para a análise fotodensitométrica. Os resultados mostraram que a exposição contínua à fumaça de cigarro promoveu uma significante redução na densidade óssea (p < 0,05) (3,22 mm Al eq ± 0,58, 2,93 mm Al eq ± 0,45, 1,86 mm Al eq ± 0,35, para os grupos 1, 2 e 3, respectivamente). Níveis semelhantes de densidade óssea foram observados nos grupos controle e interrupção (grupos 1 e 2 - p > 0,05). Portanto, dentro dos limites do presente estudo, pode-se concluir que a IFC pode influenciar a qualidade óssea da tíbia e que a interrupção da inalação parece reverter esse efeito negativo resultando numa densidade óssea semelhante à do grupo controle.


Subject(s)
Animals , Male , Rats , Bone Density , Tibia , Tobacco Smoke Pollution/adverse effects , Absorptiometry, Photon , Rats, Wistar , Tibia/physiology
12.
Indian J Physiol Pharmacol ; 2003 Jan; 47(1): 81-6
Article in English | IMSEAR | ID: sea-107158

ABSTRACT

Anti Orthostatic Hypokinetic posture in rats by tail suspension for 15 days (d) simulates the deconditioning effects of weightlessness on the weight bearing bones. The present study evaluates the effects of daily 4 hour (h) weight support (WS) during simulated weightlessness (S-W) in preventing these changes. Adult male albino rats were divided into three groups as (i) Control (CON, n = 12), (ii) Hind limb unweighing by tail suspension for 15 d (HU, n = 18), (iii) HU with daily 4 h WS (4 HRWS, n = 11). After 15 d tibia from all the animals were removed and subsequently dried, ashed and then calcium content of the bones were determined. HU showed reductions in the water content by 35.8%, organic matrix by 12.2% and calcium content by 33.4% of tibia. 4 h WS during S-W resulted in complete prevention of water loss and organic matrix loss and partial prevention of the loss of calcium content. Calcium content of tibia in 4 HRWS remained 15.2% less as compared to CON. These findings indicate that 4 h WS is partially successful in preventing the demineralisation effects of S-W on weight bearing bone tibia.


Subject(s)
Animals , Bone Demineralization, Pathologic/physiopathology , Male , Physical Conditioning, Animal/methods , Rats , Rats, Wistar , Tibia/physiology , Time Factors , Weight-Bearing/physiology , Weightlessness Countermeasures , Weightlessness Simulation/methods
13.
Rev. Hosp. Clin. Fac. Med. Univ. Säo Paulo ; 54(6): 181-6, Nov.-Dec. 1999. ilus, tab, graf
Article in English | LILACS | ID: lil-260494

ABSTRACT

Cylindrical specimens of bone measuring 15 mm in diameter were obtained from the lateral cortical layer of 10 pairs of femurs and tibias. A central hole 3.2 mm in diameter was drilled in each specimen. The hole was tapped, and a 4.5 mm cortical bone screw was inserted from the outer surface. The montage was submitted to push-out testing up to a complete strip of the bone threads. The cortical thickness and rupture load were measured, and the shear stress was calculated. The results were grouped according to the bone segment from which the specimen was obtained. The results showed that bone cortex screw holding power is dependent on the bone site. Additionally, the diaphyseal cortical bone tissue is both quantitatively and qualitatively more resistant to screw extraction than the metaphyseal tissue.


Subject(s)
Bone Screws , Femur/physiology , Tibia/physiology , Diaphyses/injuries , Diaphyses/surgery , Femur/injuries , Femur/surgery , Tensile Strength , Tibia/injuries , Tibia/surgery
14.
Professional Medical Journal-Quarterly [The]. 1998; 5 (2): 129-32
in English | IMEMR | ID: emr-49409

ABSTRACT

Effects of distraction on histology of epiphyseal plates of tibia in 30 Rabbits were studied by applying traction in long axis of right tibia. Animals were divided into three equal groups. Experimental, Sham operated and control group. Proximal and distal epiphyseal plates were prepared for histological study. On comparison of thicknesses of epiphyseal plates of all the groups no statistically significant difference was noted. Histological morphology was also similar in all the groups


Subject(s)
Animals , Tibia/physiology , Rabbits , Traction
15.
Acta ortop. bras ; 4(1): 9-14, 1996. graf, ilus
Article in Portuguese | LILACS | ID: lil-214132

ABSTRACT

O objetivo desta investigaçao foi analisar o comportamento mecânico da placa de crescimento sob algumas condiçoes. Inicialmente, foi determinada a curva de crescimento da tíbia de ratas da raça Norvegicus albinus, do 5 ao 83 dia de vida pós-natal. A partir dessa curva, foram selecionadas as idades de 25 e 65 dias para o ensaio mecânico, em razao de representarem, respectivamente, o máximo e o final de crescimento. Para os ensaios mecânicos foram usados 46 pares de tíbias, 23 para cada idade. Para cada par de tíbias, uma foi aleatoriamente ensaiada a fresco e a outra após 30 dias de congelamento a -18 graus Celsius. Todos os ensaios foram realizados à temperatura ambiente e segundo a mesma técnica. Tíbias isoladas foram adaptadas à máquina universal de ensaio mecânico, que aplicou cargas de cisalhamento na placa de crescimento proximal até que ocorresse ruptura. Foi construiída a curva carga x deformaçao. Com a medida da área da placa de crescimento foi obtida a tensao correspondente. Os seguintes parâmetros foram analisados: limite de proporcionalidade, resiliência e nódulo equivalente de elasticidade. Da análise dos rersultados concluiu-se que o congelamento da cartilagem afetou significativamente as suas propriedades mecânicas, tornando-a mais resistente aos esforços aplicados, e que a resistência mecânica ao cisalhamento foi maior na idade mais próxima do final do crescimento da tíbia.


Subject(s)
Animals , Female , Rats , Growth Plate/physiology , Tibia/physiology , Age Factors , Biomechanical Phenomena , Freezing , Rats, Wistar
16.
Rev. bras. ortop ; 25(7): 243-7, jul. 1990. ilus, tab
Article in Portuguese | LILACS | ID: lil-129236

ABSTRACT

Com o objetivo de se determinar a resistência das diversas regiöes da superfície articular, estudaram-se 15 joelhos de cadáveres frescos. Foram feitos ensaios de penetraçäo em sete diferentes pontos confrontantes da tíbia e do fêmur. Os resultados mostraram que a resistência do côndilo medial da tíbia é a maior, enquanto a do côndilo lateral é a menor. No fêmur isso näo foi observado; entretanto, a média de resistência da tíbia é igual à do fêmur e a profundidade da camada esponjosa é mais fina e superficial na tíbia que no fêmur


Subject(s)
Humans , Adult , Middle Aged , Femur/physiology , Tensile Strength , Tibia/physiology , Knee Joint/physiology
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