Rabbit growth plate morphology in temporary bilateral blocking / Morfología de la placa de crecimiento de conejos durante bloqueo bilateral temporario

Blocking of the growth plate (GP) using plates with screws (tension band plating) is a modern method used to correct deformities and moderate leg length discrepancy in growing children. Determining the duration of temporary bilateral blocking without the occurrence of irreversible changes of GP is of paramount importance important. Methods: Two-month-old Californian breed male rabbits (n=30) were exposed to bilateral blocking of the distal GP of the right femur locking plates with screws for 3, 5, and 7 weeks. The fixators were removed after 5 and 7 weeks in 18 rabbits and 3 weeks after that, animals were sacri!ced. The contralateral limb was used as a control. Histological, histomorphometric, and X-ray analyses were performed. Results: During GP blocking, its height gradually decreased. This decreased was more pronounced after 7 weeks. Destructive changes progressed with an increase in the blocking duration. Three weeks after discontinuation of the bilateral blocking that lasted 5 weeks, the height of the GP signi!cantly increased 1.2 times on the lateral side and 1.9 times on the medial side (p<0.001) compared to the control. When blocking was discontinued after 7 weeks, the structure of the GP was partially restored after 3 weeks, the height of GP signi!cantly increased 1.2 times on the lateral side, and 1.07 times on the medial side (p<0.01) compared to the control. Conclusion: Restoration of the structuralfunctional features of the GP after the removal of the plates depends on the duration of temporary bilateral blocking, which must be taken into account in the clinical setting. (AU)

El bloqueo de la placa de crecimiento (PC) utilizando placas con tornillos (banda de tensión) es un método moderno utilizado para corregir deformidades y alteraciones moderadas en la longitud de las piernas en niños en crecimiento. Es de suma importancia determinar cuál debe ser la duración del bloqueo bilateral temporal sin que ocurran cambios irreversibles en la PC. Métodos: Conejos machos de raza californiana de dos meses de edad (n = 30) fueron expuestos al bloqueo bilateral de la PC distal colocando placas del fémur derecho con tornillos durante 3, 5 y 7 semanas. Los fijadores fueron retirados después de 5 y 7 semanas en 18 de los conejos, y 3 semanas después los animales fueron sacrificados. La extremidad contralateral se utilizó como control. Se realizaron análisis histológicos, histomorfométricos y de rayos X. Resultados: Durante el bloqueo de la PC, su altura disminuyó gradualmente. Esta disminución fue más pronunciada después de 7 semanas. Los cambios destructivos se incrementaron a medida aumentaba la duración del bloqueo. Tres semanas después de la interrupción del bloqueo bilateral que duró 5 semanas, la altura de la PC aumentó significativamente 1.2 veces en el lado lateral y 1.9 veces en el lado medial (p <0.001) en comparación con el control. Conclusión: La restauración de las características funcionales estructurales de la PC después de la extracción de las placas depende de la duración del bloqueo bilateral temporal, lo que debería tenerse en cuenta en el tratamiento clínico de estas alteraciones. (AU)

Undernutrition impairs the quality of growth plate and trabecular and cortical bones in growing rats

Abstract Purpose: To investigate the effects of dietary restriction on the growth plate and long bone tissue in growing rats. Methods: Sixty male Wistar rats were randomly assigned to two groups: Control (Con) and Diet-restricted (Res). After weaning, the Res rats were offered 50% of the chow ingested by the control (ad libitum food intake). The animals were subdivided into two subgroups with follow-ups up to 56 or 70 days. After euthanasia, the growth plate of tibias was analyzed by histomorphometry, micro-computed tomography, and mechanical test. The trabecular and compact bones were evaluated by histomorphometry, dual-energy X-ray absorptiometry, and micro-computed tomography (μCT). Real-time PCR was used to analyze gene expression. Results: Although dietary restriction did not alter gene expression, several phenotypic changes were seen in the growth plate; i.e., decrease in volume, reduction in total area and height, decrease in the area ossified zones, mechanical weakening, reduction in mass of trabecular and cortical bone, lower bone density, deterioration of the trabecular and cortical microarchitecture, and trabeculae with lower collagen deposition. Conclusion: Dietary restriction had severe detrimental effects on the growth plate and trabecular and cortical bone.

Effects of underwater lipus on the morphohistology of the CF-1 mice growth plate in late lactation stage / Efectos del ultrasonido subacuático sobre la morfohistología de la placa de crecimiento de ratones CF-1 en etapa de lactancia tardía

SUMMARY: Ultrasound is one of the most used tools in physiotherapy, its LIPUS modality allows to treat musculoskeletal injuries, but like the conventional ultrasound it is contraindicated its application in areas close to growth cartilage by a possible closure of this one. In the literature there is no conclusive evidence of this contraindication, so the objective of the present study is to evaluate the effects of doses equivalent to underwater LIPUS on the histomorphometry of the proximal tibial epiphysis growth plate in an animal model. LIPUS was applied in underwater mode in the right pelvic limb to 8 mice in p 15 for 4 days, 2 times a day. On completion of 8 sessions the histology of the stimulated limb growth plate was sacrificed and the histology. When evaluating the histomorphometry of the plaque, a significant increase in the thickness and area of the proliferative zone stimulated with LIPUS (p = 0.048) was observed. In the hypertrophic area were observed no significant differences in thickness or areas, but in the hypertrophic area there were significant changes in the histological organization, observing a significant increase of the entire columns in the stimulated plaque (p = 0.04). LIPUS in underwater modality modifies the histomorphometry of the proximal epiphyseal PC of the tibia of rodents in the late postnatal stage, promoting proliferation and columnar organization in the proliferative and hypertrophic zone, respectively.

RESUMEN: El ultrasonido es una de las herramientas más utilizadas en fisioterapia, su modalidad LIPUS permite tratar lesiones músculo-esqueléticas, pero al igual que el ultrasonido convencional está contraindicada su aplicación en zonas próximas a cartílago de crecimiento por un posible cierre de éste. En la literatura no existe evidencia contundente de esta contraindicación, por lo cual el objetivo del presente estudio fue evaluar los efectos de dosis equivalentes a LIPUS subacuático sobre la histomorfometría de la placa de crecimiento de la epífisis proximal de tibia en un modelo animal. Metodología. Se aplicó LIPUS en modalidad subacuática en el miembro pélvico derecho a 8 ratones en p 15 por 4 días, 2 veces al día. Al cumplir 8 sesiones se sacrificaron y se evaluó la histología de la placa de crecimiento del miembro estimulado. Al evaluar la histomorfometría de la placa se observó un aumento significativo en el espesor y el área de la zona proliferiva estimulada con LIPUS (p=0.048). En la zona hipertrófica no se observaron diferencias significativas en el espesor ni en las áreas, pero si existieron cambios significativos en la organización histológica de la zona, observando un aumento significativo de las columnas completas en la placa estimulada (p=0,04). El LIPUS en modalidad subacuática modifica la histomorfometría de la PC epifisiaria proximal de la tibia de roedores en el etapa postnatal tardía, promoviendo la proliferación y la organización columnar en la zona proliferativa e hipertrófica, respectivamente.

Mutações em heterozigose no gene do receptor tipo B dos peptídeos natriuréticos (NPR2) são causa de baixa estatura inicialmente classificada como idiopática / Heterozygous mutations in natriuretic peptide receptor-B gene (NPR2) are cause of short stature initially classified as idiopathic

Nos últimos anos, o sistema do peptídeo natriurético do tipo C (CNP) e seu receptor (NPR-B) foi apontado como um importante regulador do processo de ossificação endocondral. Vários estudos em animais evidenciam o seu papel de estímulo à proliferação e diferenciação de condrócitos e secreção de matriz extracelular. Mutações bialélicas com perda de função do gene do NPR-B (NPR2) levam a uma doença denominada displasia acromesomélica do tipo Maroteaux (AMDM), uma displasia esquelética caracterizada por baixa estatura extrema. Observa-se que familiares de pacientes com AMDM carreadores de mutação no NPR2 têm estatura abaixo da média da população a qual pertencem, sugerindo um papel de mutações em heterozigose do NPR2 como causadoras de baixa estatura idiopática (BEI). Os objetivos deste estudo foram avaliar a presença de mutações no gene NPR2 em um grupo de pacientes com BEI e correlacionar os achados moleculares com o fenótipo dos pacientes e familiares. A região codificadora do gene NPR2 foi sequenciada pelo método de Sanger em 60 pacientes com diagnóstico de BEI. Foram identificadas cinco diferentes variantes alélicas missense em heterozigose no NPR2, cada uma em um único paciente. Essas variantes foram submetidas à análise funcional in vitro para avaliação da atividade da guanililciclase e microscopia confocal para localização intracelular dos receptores NPR-B. As variantes c.226T > C / p.Ser76Pro, c.788G > C / p.Arg263Pro e c.2455C > T / p.Arg819Cys segregam com o fenótipo de baixa estatura dentro das famílias e determinam um prejuízo funcional ao NPR-B. As três variantes geram proteínas que exercem efeito dominante negativo e os receptores NPR-B com as mutações p.Ser76Pro e p.Arg263Pro não se localizam na membrana celular. As variantes c.491C > G / p.Ala164Gly e c.1636A > T / p.Asn546Tyr não segregam com o fenótipo de baixa estatura nas famílias e não se evidenciou um efeito dominante negativo. O escore-Z da altura dos indivíduos carreadores das variantes...

Over the past several years, C-type natriuretic peptide (CNP) and its receptor (NPR-B) system has emerged as an important regulator of endochondral bone growth. Animal models showed a CNP/NPR-B role in promoting chondrocyte proliferation and differentiation and matrix synthesis. Biallelic loss-of-function mutations in NPR-B gene (NPR2) cause acromesomelic dysplasia type Maroteux (AMDM), a skeletal dysplasia with extreme short stature. Relatives of patients with AMDM, heterozygous for NPR2 mutations, were noted to be shorter than expected for their population of origin, suggesting that heterozygous mutations in NPR2 could be a cause of idiopathic short stature (ISS). The objective of this study was to investigate the presence of NPR2 mutations in a group of patients with ISS and to correlate molecular findings with phenotype. The NPR2 coding region was sequenced by Sanger's method in 60 patients with ISS. Five different heterozygous missense variants in NPR2 were identified in five patients. The functional consequences of those variants were established using in vitro cell-based assay to determine guanylate cyclase activity and confocal microscopy to determine intracellular localization of NPR-B. The variants c.226T > C / p.Ser76Pro, c.788G > C / p.Arg263Pro and c.2455C > T / p.Arg819Cys segregated with short stature phenotype and were functionally deleterious. NPR-B receptors with these three variants have a dominantnegative effect and p.Ser76Pro and p.Arg263Pro NPR-B were not localized in the cell membrane. Cosegregation analysis of the variants c.491C > G / p.Ala164Gly and c.1636A > T / p.Asn546Tyr was inconclusive and they did not have a dominant negative effect. Carriers of functionally deleterious variants have a height SD score that ranged from -4.5 to -1.7. One of these patients and two relatives have disproportionate short stature and one has shortened metacarpal. In conclusion, heterozygous mutations in NPR2 gene are cause of short stature in...

Low-level laser on femoral growth plate in rats / Laser terapêutico de baixa potência na placa de crescimento de ratos

PURPOSE: To determine the influence of low-level laser therapy on femoral growth plate in rats. METHODS: Thirty male Wistar rats aged 40 days were divided into two groups, G1 and G2. In G1 the area of the distal growth plate of the right femur was irradiated at one point using GaAlAs laser 830 nm wavelength, output power of 40 mW, at an energy density of 10 J/cm². The irradiation was performed daily for a maximum of 21 days. The same procedure was done in G2, but the probe was turned off. Five animals in each group were euthanized on days 7, 14 and 21 and submitted to histomorphometric analysis. RESULTS: In both groups the growth plate was radiographically visible at all moments from both craniocaudal and mediolateral views. On the 21st day percentage of femoral longitudinal length was higher in G2 than G1 compared to basal value while hypertrophic zone chondrocyte numbers were higher in G1 than G2. Calcified cartilage zone was greater in G1 than in G2 at all evaluation moments. Angiogenesis was higher in G1 than in G2 at 14th and 21st days. CONCLUSION: The low-level laser therapy negatively influenced the distal femoral growth plate.

OBJETIVO: Determinar a influência do Laser Terapêutico de Baixa Potência sobre a placa de crescimento de ratos. MÉTODOS: Trinta ratos Wistar machos com 40 dias de idade foram divididos em dois grupos, G1 e G2. O grupo G1 foi submetido à irradiação com laser GaAlAs 830 nm, potência de saída de 40 mW, e densidade de energia de 10 J/cm2. A irradiação foi aplicada diariamente por um período máximo de 21 dias. O mesmo procedimento foi realizado no grupo G2, com a probe desativada. Cinco animais em cada grupo foram sacrificados nos dias 7, 14 e 21 e submetidas à análise histomorfométrica. RESULTADOS: Em ambos os grupos, o disco fisário esteve radiograficamente visível em todos os momentos nas incidências craniocaudal e médio-lateral. No 21º dia a porcentagem de comprimento longitudinal do fêmur foi maior em G1 que em G2 em relação ao valor basal, e o número de condrócitos da zona hipertrófica foi maior em G1 que em G2. A zona de cartilagem calcificada estava maior em G1 em relação a G2 em todos os momentos de avaliação. A angiogênese foi maior em G1 que em G2 nos 14º e 21º dias. CONCLUSÃO: A terapia com laser terapêutico de baixa potência influenciou negativamente o disco fisário distal do fêmur de ratos.

Physeal Growth Arrest by Excessive Compression: Histological, Biochemical, and Micro-CT Observations in Rabbits

BACKGROUND: Compressive force across the growth plate may cause retardation and even arrest of physeal growth. The purpose of this study was to investigate histologic changes, metabolic changes in terms of glycosaminoglycan (GAG) concentration, and contrast-enhanced micro-computed tomography (CEMCT) findings of physeal cartilage in a rabbit model of physeal damage caused by excessive compression. METHODS: Compressive forces were applied via external fixators for two weeks to the growth plates of distal femurs and proximal tibiae of right hind-legs in 8-week-old rabbits. Left hind-legs remained intact and were used as controls. Forty-four bone specimens containing growth plates of distal femurs or proximal tibiae were harvested one week (n = 12) and four weeks (n = 32) after surgery, and examined for histologic findings (H&E staining) and GAGs quantification in physeal cartilage. After incubation in an ionic contrast material for 48 hours, specimens were scanned by CEMCT, and the pixel values of physeal cartilage were measured. RESULTS: CEMCT showed a thin, highly attenuated line parallel to the growth plate in compressed specimens harvested at four weeks after surgery, which was found to be transversely connected trabecular bone. In these specimens, GAG content in physeal cartilage was significantly lower, and CEMCT pixel values of physeal cartilage were significantly higher than in the specimens from the contralateral control side. CONCLUSIONS: Excessive compressive force applied to growth plates produces altered histologic features and metabolic function in terms of decreased GAG content in physeal cartilage, changes that can be demonstrated by CEMCT.

Les traumatismes du cartilage de croissance chez l'enfant : aspects épidémiologiques, lésionnels et thérapeutiques à propos de 44 cas

Objectif : Evaluer la fréquence des traumatismes du cartilage de croissance, faire ressortir les aspects thérapeutiques des traumatismes du cartilage de croissance chez l'enfant et en évaluer les résultats afin d'améliorer leur prise en charge. Patients et méthode : Il s'agit dune étude rétrospective portant sur 44 dossiers d'enfants âgés de moins de 15 ans allant de la période du 1er janvier 2002 au 31 décembre 2006, hospitalisés et traités dans le service de chirurgie pédiatrique du CHU Tokoin de Lomé pour traumatisme du cartilage de croissance. Résultats : La prévalence des traumatismes du cartilage de croissance était de 3,6% avec une prédominance masculine (59,1 %). L'âge moyen était de 9.8± 3,2 ans. Les lésions de type 2 de Salter et Harris avaient représenté 44% des cas. Les accidents de jeu en étaient les principaux pourvoyeurs (41 %) avec une affluence dans les mois d'avril et d'août. L'atteinte de l'extrémité inférieure du fémur avait représenté 28,9% des cas. Le traitement orthopédique était appliqué dans 64 4% des cas. Avec un recul moyen de 2 ans, 4 patients avaient présenté des séquelles. Conclusion : Les traumatismes du cartilage de croissance ont une fréquence relativement faible. Les pièges diagnostiques des traumatismes du cartilage de croissance sont nombreux et sont parfois à l'origine d'erreurs thérapeutiques. Leur prise en charge doit être bien codifiée pour éviter des séquelles à long terme

Comparación entre resultados obtenidos en la corrección de valgo tibial proximal en pacientes pediátricos con sistema de grapas y sistema de placas en el Hospital Ortopédico Infantil Caracas Venezuela 2000-2007 / Comparison of results obtained in the proximal tibial valgus correction in pediatric patients with staple system and system of plaques in the Hospital Ortopédico Infantil 2000-2007 Caracas Venezuela

Las deformidades axiales de los miembros inferiores, motivo de consulta habitual, no corregen espontáneamente si son persitentes y sginificativas. La epifisiodesis produce la corrección grudual de la deformidad en un procedimiento mínimamente invasivo, en pacientes esqueléticamente inmaduros, en genu valgum y varum, con grapas o placas y tornillos. Según las observaciones clínicas, las placas permiten un mejor resultado en tiempo más corto, menor daño a la fisis y menos riesgo de complicaciones o falla de material en comparación con las grapas. La comparación de las técnicas en engrapado y placa en la resolución de deformidades en valgo de tibia proximal en los pacientes pediátricos en el Hospital Ortopédico Infantil, durante el periodo 2000 al 2007. Estudio retrospectivo simple y comparativo, se evaluaron 36 pacientes de ambos sexos con el diagnostico de Valgo Proximal Tibial, idiopáticos o asociados a otras patologías, que fueron tratados en el Hospital Ortopédico Infantil durante 2000 al 2007 con las técnicas de grapa y placa, mediante revisión de controles pre y postoperatorios de la historia clínica, y por medición radiológica de los ángulos FDLm, TPMm y MAD en radiogrfías panorámicas pre y postoperatorias. Se estudiaron 36 pacientes de ambos sexos, (16 varones y 20 niñas), promedio de edad de 10 años +/- 3,3 años. Existen similitudes en los primeros 12 meses en esta muestra, pero a partir de ese momento la Placa alcanza los valores de corrección antes que las grapas. Según la pendiente Y, la placa se proyecta para correcciones de 6,62 mm cada 6 meses, en cambio la grapa se proyecta para correciones de 5,72 mm cada 6 meses. Los valores del ángulo se estabilizan con la placa, y en cuanto a la grapa, se continúa la corrección en sentido contrario. La pendiente Y indica que la placa corrige -1,95º cada 6 meses, y la grapa corrige -2,95º cada 6 meses hacia el varo. Según la prueba ANOVA, combinando las variables Tiempo-Material, la placa alcanza....

The axial deformities of the lower limbs, common reason for consulation, will not correct spontaneously if they are persistent and significant. Epiphysiodesis produce gradual correction of deformity in a minimally invasive procedure in skeletally immature patients in valgum and genu varum with staples or plates and screws. According to clinical observations, the plates allow a better result in shorter time, less damage to the physis and less risk of complications or failure of material compared with the staples. Comparison of stapling techniques and plaque in the resolution of valgus deformity of proximal tibian in pediatric patients at Children's Orthopedic Hospital during the period 2000 to 2007. A retrospective and comparative simple, we evaluated 36 patients of both sexes with a diagnosis of Proximal Tibial Valgus, idiopathic or associated with other diseases, which were treated at the Children's Orthopedic Hospital during the period 2000 to 2007 with the techniques staple and plate by reviewing pre-and postoperative checks of medical record, and radiological measurements of the angeles FDLm, TPMm, and MAD in pre-and postoperative panoramic radiographs. We studied 36 patients of both sexes (16 boys and 20 girls), mean age 10 +/- 3,3 years. There are similarities in the first 12 months in this sample, but from that moment on the plate reaches the values of correction rather than staples. According to the slope and The plate is projected to corrections from 6,62 mm every 6 months, however the clip is projected to corrections of 5,72 mm every 6 months. The angle values are e¡stabilized with the plate, and as for the clip, continue the correction in the opposite direction. The slope indicates that the board and fixes -1,95º every six months, and the clip fixes -2,95º every six months into varus. According to the ANOVA test, combining the time-material variables, the plate reaches the expected correction before on the staple, the period aroun 12 months would.....

Proceso biológico del desarrollo epifisario:: aparición y formación del centro secundario de osificación / Processus biologique du développement épiphysaire:: survenue et formation du point d'ossification secondaire / Biological process of epiphyseal development:: appearance and formation of secondary center of ossification

Los huesos se constituyen de tejido conectivo especializado que conforma el principal órgano de soporte del cuerpo. Las epífisis de los huesos largos experimentan durante el período perinatal diversos cambios estructurales que conllevan a la formación del centro secundario de osificación (CSO), responsable del crecimiento esférico de la epífisis. En este artículo se exponen los cambios biológicos característicos de las diversas etapas del desarrollo del CSO, mediante una descripción detallada de los eventos histológicos que ocurren en cada etapa e ilustrando la coordinación de procesos y el patrón de desarrollo epifisario. Por consiguiente, este artículo facilitará la comprensión de dichos procesos, la creación de modelos matemáticos de los diferentes eventos y proporcionará una base teórica para trabajos futuros que investiguen el desarrollo y crecimiento epifisario(AU)

Bones are the specialized connective tissue shaping the main support organ of the body. Long bone epiphysis underwent many structural changes during the perinatal period leading to formation of a secondary center of ossification (SCO), accounting for the epiphyseal spherical growth. In present paper are exposed the characteristic biological changes of the different SCO development stages thorough a detailed description of histological events occurring in each stage and illustrating the processes coordination and the epiphyseal development pattern. Therefore, present article will allows the understanding of such processes, creation of mathematical models of different events, as well as a theoretical basis for future papers researching the epiphyseal development and growth(AU)

Les os sont constitués de tissu connectif spécialisé formant l'organe de support principal du corps. Les épiphyses des os longs subissent plusieurs changements de structure lors de la période périnatale impliquant la formation du point d'ossification sécondaire (POS), responsable de la croissance sphérique de l'épiphyse. Dans cet article, les changements biologiques caractéristiques des diverses étapes du développement du POS sont exposés par une description détaillée des évènements histologiques se produissant dans chaque étape, et en montrant la coordination des processus et le modèle de développement épiphysaire. Cet article va donc faciliter la compréhension de ces dits processus, la création de modèles mathématiques des différents évènements, et donner une base théorique pour des travaux futurs étudiant le développement et la croissance épiphysaires(AU)

Avaliação por imagem das lesões da placa de crescimento / Imaging of growth plate injuries

As estruturas responsáveis pelo crescimento do osso incluem a fise (também chamada placa de crescimento) e as epífises. Afecções que acometem pacientes com o esqueleto imaturo, ou seja, com a placa de crescimento ainda aberta, podem interferir no crescimento ósseo, resultando em complicações como parada do crescimento, encurtamento dos membros ou deformidades angulares. Condições traumáticas que resultam muitas vezes em fraturas epifisárias são a causa mais comum das lesões da placa de crescimento. A avaliação cuidadosa desses pacientes pelos métodos de diagnóstico por imagem atualmente disponíveis, sobretudo a radiografia, a tomografia computadorizada e a ressonância magnética, permite o reconhecimento precoce do comprometimento das estruturas relacionadas ao crescimento ósseo, além de tratamento adequado, diminuindo a possibilidade do desenvolvimento de tais complicações.

The structures responsible for the growth of bones include the physis (also called growth plate) and the epiphysis. Affections involving patients with immature skeletons, i.e., with a still open growth plate, may affect the bone growth, resulting in complications such as growth arrest, limb shortening and angular deformities. Traumatic conditions, many times resulting in epiphyseal fractures, are the most frequent cause of growth plate injuries. A careful evaluation of these patients by means of currently available imaging methods, especially radiography, computed tomography and magnetic resonance imaging, allows an early diagnosis of the involvement of structures related to the bone growth, besides an appropriate management, reducing the probability of secondary complications.

Effect of Ciprofloxacin on growing cartilage in albino Rat pups

Administration of quinolone therapy is controversial during growing age as stated by earlier worker. The flroquinolones are currently not indicated for young children, because of arthropathy and adverse effect on growing cartilage shown by studies. However the effects of ciprofloxacin on epiphyseal growth plate has remained undocumented. This study is therefore, undertaken to determine the risk of ciprofloxacin administration an growing cartilage by prospective experimental animal study model using Wistar albino rat pups. Ciprofloxacin was administered to newly born Wistar albino rat pups with a doze of 20mg/kg body weight intraperitonealy twice a day from day-1 to day-14 after birth. The animals were sacrificed by deep ether anesthesia. The limbs were disarticulated from axial skeleton, soft tissue was removed. The intact bone mean length in millimeter of right and left humerus and femur was measured with the help of electronic vernier caliper and bones were fixed in 10% buffered farmalin. Decalcification was done in 10% nitric acid and 10% formic acid changes. After paraplast embeding, 4 mm thick longitudinal sections of the proximal long bones were cut by a rotary microtome. Routine staining with haemotoxylin and eosin was performed. Histomorphometry was done measuring the thickness of epiphyseal cartilage and was compared with similar value of control animals. The results were statistically analysed to find out the significance. The ciprofloxacin induces a mordanting effect as abviated by increased basophilia. Our study reveales that cirprofloxacin administration in the newly born pups decreased the width of epiphyseal growth plate cartilage by 10.43% in humerus and 4.72% in femur as compared to the growth of control cartilage. The decrease in the width was brought about mainly by the reduced count of the proliferative cells in the proliferative zone and the diminuation in the average size of the hypertrophic condryocytes in the hypertrophic zone. The reserve zone has become markedly reduced in thickness. The ciprofloxacin post-natal administration effected growth plate retardation by inhibiting the mitosis in the proliferative zone and also effected the mean length of humora and femora leading to reduction in limb length of rat pups

Gadolinium-enhanced MR imaging of epiphyseal and metaphyseal marrow in normal piglets / 华中科技大学学报（医学）（英德文版）

The purpose of this study is to define the appearance of normal epiphyseal and metaphyseal marrow and normal changes of marrow due to fatty conversion on Gadolinium (Gd)-enhanced MR Imaging. Unenhanced and enhanced T1-weighted MR imaging were performed in proximal and distal femoral ends of 8 healthy piglets at the ages of 2, 4, 6 and 8 weeks, respectively. The changes with age in signal intensity and enhancement ratio of the epiphyseal and metaphyseal marrow with age were examined. The correlation of MRI characteristics with histological findings was studied. Our study showed that marrow of the metaphysis and of periphery of the 2nd ossification center were well vascularized hematopoietic marrow and had great enhancements. The enhancement ratio of metaphysis was greater than that of epiphyseal marrow and both enhancement ratios degraded gradually with age. The central regions of the epiphyseal ossification center and of the diaphysis were of fatty marrow and had little enhancement. It is concluded that on Gd-enhanced MR imaging the hematopoietic marrow of metaphysis and of periphery of the 2nd ossification center had greater enhancement than that of fatty marrow of central region of the 2nd ossification center. All of their enhancements decreased gradually with age.

MRI characteristics and transverse relaxation time measurements in normal growing cartilage / 华中科技大学学报（医学）（英德文版）

To determine the characteristics of magnetic resonance (MR) signals of normal growing cartilage and identify the difference in transverse relaxation times between physeal and epiphyseal cartilage in vivo. 24 distal femora of 12 two-week-old piglets were imaged on a 1.5 Tesla GE MR scanner. Comparison was made between signal intensity on MR images and the structure shown in corresponding histologic sections. T2 values were measured in eight piglets by means of multiecho spin-echo sequences. Our results showed that MR imaging delineated five regions between the secondary ossification center and the metaphysis, which histologically correspond to the zone of provisional calcification of the secondary ossification center, physis of the secondary ossification center, epiphyseal cartilage, physis and zone of provisional calcification. The T2 value in the physeal cartilage was much larger than that in the epiphyseal cartilage (P<0.05). It is concluded that MRI findings could differentiate the different regions of growing cartilage. T2 is longer in physeal than in epiphyseal cartilage, perhaps reflecting differences in water binding by proteoglycans.

Determinación de la edad en que cierran las placas de crecimiento en las rodillas de conejos de raza Nueva Zelanda / The age of physeal closure in the knee of New Zelanda rabbits

La finalidad de este estudio fue determinar la edad del cierre de las placas de crecimiento en la zona de la rodilla de los conejos de raza Nueva Zelanda. Se estudiaron 124 conejos de diferentes edades mediante radiografías simples y cortes histológicos. Se concluyó que el cierre fisiario distal del fémur acontece entre 131 y 166 días. Para la placa de crecimiento proximal de la tibia, el cierre fisiario tiene lugar entre 176 y 197 días. Los estudios radiológicos e histológicos discreparon para el fémur en 3.6% de los casos, para la tibia el 10.9%, y para el peroné el 16.4%; es decir, casos en los que la fisis no era visible radiológica pero si histológicamente.