Intrauterine alcohol exposure disturbs trabecular morphology in the Sprague Dawley rat humerus epiphysis up to 3- weeks postnatally / La exposición al alcohol intrauterino altera la morfología trabecular en la epífisis del húmero de la rata Sprague Dawley hasta 3 semanas después del nacimiento

SUMMARY: Gestational alcohol exposure inhibits neurological as well as bone growth and development both in fetal and postnatal life. Stunted stature, osteoporosis and fractures in adult life are some of the adverse effects. While the impact of intrauterine alcohol on the brain has been extensively investigated, studies on the effects on bone are relatively few. Therefore, our study aimed to examine the impact of prenatal alcohol exposure on bone microarchitecture in 3-week-old rats using Micro-focus X-Ray Computed Tomography (Micro CT). Time mated pregnant Sprague Dawley dams (13) were randomly placed into 3 groups: ethanol (n=5), saline control (n=5) and untreated control (n=3). The former 2 groups received treatment with 0.015ml/g of 25.2 % ethanol and 0.9 % saline, respectively, for the first 19 days of gestation. The untreated group received no treatment. The pups remained with their dams until termination at 21 days of age. From each dam, 2 pups were collected resulting in: ethanol (n=10), saline controls (n= 10) and untreated controls (n = 6). The humeri of the pups were dissected and scanned using a 3D-μCT scanner (Nikon XTH 225L) at 15μm resolution. Trabecular and cortical parameters were analysed using Volume Graphics Studio® software following reconstruction. Results showed a decrease in trabecular size, spaces, thickness, and volume. There was a decrease in cortical bone area in the ethanol group compared to the controls. These findings may suggest that osteoporosis and fractures seen as gestational alcohol effects may be due to compromised trabecular structure.

RESUMEN: La exposición al alcohol durante la gestación inhibe el crecimiento y desarrollo neurológico y óseo tanto en la vida fetal como posnatal. Algunos de los efectos adversos incluyen la estatura atrofiada, osteoporosis y fracturas en la vida adulta. Si bien se ha estudiado el impacto del alcohol intrauterino en el cerebro, los estudios sobre los efectos en los huesos son escasos. Por lo tanto, nuestro estudio tuvo como objetivo examinar el impacto de la exposición prenatal al alcohol en la microarquitectura ósea en ratas de 3 semanas de edad utilizando Tomografía Computarizada de Rayos X Micro-focus (Micro CT). Las hembras de Sprague Dawley preñadas con apareamiento temporal (13) se colocaron aleatoriamente en 3 grupos: etanol (n = 5), control de solución salina (n = 5) y control sin tratar (n = 3). Los primeros 2 grupos recibieron tratamiento con 0,015 ml /g de etanol al 25,2 % y solución salina al 0,9 %, respectivamente, durante los primeros 19 días de gestación. El grupo no tratado no recibió tratamiento. Las crías permanecieron con sus madres hasta la terminación a los 21 días de edad. De cada madre, se recolectaron 2 crías que dieron como resultado: etanol (n = 10), controles salinos (n = 10) y controles no tratados (n = 6). Se diseccionaron y escanearon los húmero de las crías usando un escáner 3D-μCT (Nikon XTH 225L) a una resolución de 15 μm. Los parámetros trabeculares y corticales se analizaron utilizando el software Volume Graphics Studio® después de la reconstrucción. Los resultados mostraron una disminución en el tamaño trabecular, los espacios, el grosor y el volumen. Hubo una disminución en el área del hueso cortical en el grupo de etanol en comparación con los controles. Estos hallazgos pueden sugerir que la osteoporosis y las fracturas por causa de los efectos del alcohol gestacional se pueden deber a una estructura trabecular comprometida.

Prediction Method of Elastic Modulus of Trabecular Bone Based on SE-DenseVoxNet / 中国医疗器械杂志

Osteoporosis is one of the common metabolic diseases, which can easily lead to osteoporotic fractures. Accurate prediction of bone biomechanical properties is of great significance for the early prevention and diagnosis of osteoporosis. Bone mineral density measurement is currently used clinically as the gold standard for assessing bone strength and diagnosing osteoporosis, but studies have shown that bone mineral density can only explain 60% to 70% of bone strength changes, and trabecular bone microstructure is an important factor affecting bone strength. In order to establish the connection between trabecular bone microstructure and bone strength, this paper proposes a prediction method of trabecular bone modulus based on SE-DenseVoxNet. This method takes three-dimensional binary images of trabecular bone as input and predicts its elastic modulus in the z-axis direction. Experiments show that the error and bias between the predicted value of the method and the true value of the sample are small and have good consistency.

A micro-CT study of different regions of the atlas / Un estudio de micro-CT de diferentes regiones del atlas

This study aimed to examine the differences in bone microarchitecture between different regions of the atlas in 28 dry atlas specimens using micro-CT, in order to explain the mechanism of the predilection sites of atlas fractures from the morphological point of view. A total of 28 dry specimens of intact adult atlas were randomly selected, scanned by micro-CT, and divided into a region from the anterior arch midpoint (AAM) to the lateral masses (LM), a LM region, and a region from the LM to the posterior arch midpoint (PAM). Trabecular thickness, separation, number, connectivity, and structure model index were measured for each of the three regions using the built-in software of the CT scanner. Trabecular thickness was all measured to be 0.11 ± 0.00 mm for AAM to LM, LM, and LM to PAM. Trabecular separation: AAM to LM > LM to PAM > LM. Trabecular number: LM > LM to PAM > AAM to LM. Connectivity: LM > LM to PAM > AAM to LM. Structure model index: LM > LM to PAM > AAM to LM. A lower trabecular number and connectivity and higher trabecular separation were seen in the anterior and posterior arches of the atlas, in which higher fracture rates were reported. By contrast, a higher trabecular number and connectivity and lower trabecular separation were seen in the lateral masses, in which lower fracture rates were reported.

Este estudio tuvo como objetivo examinar las diferencias en la microarquitectura ósea entre diferentes regiones del atlas en 28 muestras de atlas secas utilizando micro-CT, con el fin de informar el área de mayor frecuencia en las fracturas de atlas, desde el punto de vista morfológico. Se seleccionaron al azar un total de 28 muestras secas de atlas adultos intactas las que se escanearon por micro-CT y se dividieron en una región desde el punto medio del arco anterior (MAA) hasta las masas laterales (ML), una región ML y una región desde el ML hasta el punto medio del arco posterior (MAP). Se midió el grosor trabecular, la separación, el número, la conectividad y el índice del modelo de estructura para cada una de las tres regiones utilizando el software incorporado del escáner CT. El grosor trabecular se midió en 0,11 ± 0,00 mm para MAA a ML, ML y ML a MAP. Separación trabecular: MAA a ML> ML a MAP> ML. Número trabecular: ML> ML a MAP> MAA a ML. Conectividad: ML> ML a MAP> MAA a ML. Índice del modelo de estructura: ML> ML a MAP> MAA a ML. Se observó un menor número de estructuras trabeculares y conectividad y una mayor separación trabecular en los arcos anterior y posterior del atlas, en los que se informaron tasas de fracturas más altas. Por el contrario, se observó un mayor número de estructuras trabeculares y conectividad, y una menor separación trabecular en las masas laterales, en las que se observó un número menor de fracturas.

Micro-finite Element Analysis of Bony Acetabulum with a Press-fit Acetabular Cup / 医用生物力学

Objective To investigate the trabecular stress distributions on the cortical bone and determine whether the cancellous bone can share the load of the acetabulum with a press-fit acetabular cup. Methods The acetabulum was scanned via micro-computed tomography (CT) to build a three-dimensional micro-finite element analysis (μFEA) model of the acetabulum. The trabecular stress and strain of the bony acetabulum were calculated following total hip arthroplasty (THA) to investigate the biomechanical characteristics of their distributions. Results With the implantation of the press-fit acetabular cup into the acetabulum, the high-stress zone of the articular surface was found to be located in the pubic bone area, with a maximum stress of 1.398 MPa. The largest high-stress zone within the articular surface was at the craniomedial part where it was supported by the iliac. For the cancellous bone within the acetabulum, the high stress was relatively widely distributed on the craniomedial part. When a 1.372 kN load was applied, the high stress was found at the craniomedial and anterior-inferior parts of the articular surface where it was supported by the iliac and pubic bone, with a trabecular micro-damage occurring in the anterior-inferior part. The highest tensile stress at the craniomedial part was 0.604 MPa. For the cancellous bone within the acetabulum, the high stress was mainly distributed on the craniomedial and anterior-inferior parts. Conclusions The high stress near the periphery of the articular surface showed a three-point circular distribution, which was mainly distributed on the iliac, ischial, and pubic bone area. The stress was distributed more uniformly owing to the deformation of the cancellous bone in the acetabulum. The cancellous bone in the acetabulum has the function of load-bearing.

The effectiveness of 3D printed titanium alloy trabecular reconstruction rod for the treatment of early osteonecrosis of femoral head / 天津医药

Objective To evaluate the safety of 3D printed titanium alloy trabecular reconstruction rod, bone grafts and its clinical efficacy. Methods Sixty patients with osteonecrosis of femoral head (ONFH) stageⅡ(ACROⅡ) were randomly divided into experimental group (titanium rod group) and control group (tantalum rod group). Patients were followed up at 6, 12 and 24 months after the operation. Harris score and visual analogue scale (VAS) were used to evaluate the postoperative function. Changes of X-ray were observed before and after operation. The imaging evaluation was analyzed after 24 months. Results The Harris score was decreased in titanium rod group compared with that of tantalum rod group at six-month. There were no significant differences in Harris scores for other time points between two groups. Repeated measures analysis of variance showed that there was a significant difference in time effect. The X-ray staging results changed gradually before and after operation in two groups, stage Ⅲand stage Ⅳgradually increased with time. There was progress in ONFH after operation in two groups. No infection or rejection was found in the two groups. There were higher improvement rates of stageⅡA and stageⅡB. There were no significant differences in improvement rate and hip preservation rate between two groups. The transparent lines disappeared in the positive and lateral X-ray films 6 months after the operation. No new transparent lines were found. The bone enhancement was not found in two groups of patients during follow-up period. No stress occlusion and bone trabecular bone enhancement were observed in two groups. Conclusion Titanium rods are satisfactory for the treatment of femoral head necrosis in the early stage of ACRO Ⅱ, which is not recommended for the treatment of relatively large ACROⅡC stage of necrotic area.

Potential for Osseous Regeneration of Platelet Rich Fibrin: A Comparitive Study in Mandibular Third Molar Socket.

Aims: To evaluate the effi cacy of autologous platelet- rich fi brin in regeneration of bone and to assess clinical compatibility of the material in mandibular third molar extraction socket. Materials and Methods: This study was conducted in 20 patients visiting the out patient department of Oral & Maxillofacial Surgery, Subbaiah Institute of Dental Sciences. Patients requiring extraction of bilateral symmetrical mandibular third molars were taken for the study. Following extraction, platelet rich fi brin prepared from patients own blood was placed in one extraction socket. The patients were assessed for postoperatively pain, periodontal pocket depth and bone blending and trabecular formation. Radiological assessment of the extraction site was done for a period of 6 months to evaluate the change in bone density. Results: All the local signs and symptoms of infl ammation were mild to moderate and subsided in normal course of time. Pain was less in study site compared to control site. Soft tissue healing was better in study site. Evaluation for bone blending and trabecular bone formation showed earlier in study (prf)site compared to control(non prf) site in 10 patients. The evaluation of bone density by radiological assessment showed the grey level values calculated at 4months at the prf site were comparatively higher than the average baseline value of bone density at extraction site in control site. Conclusion: The study showed that autologous PRF is biocompatible and has signifi cant improved soft tissue healing,bone regeneration and increase in bone density in extraction sockets. However a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding its effi cacy.

Effects of eugenol on resting tension of rat atria

In cardiac and skeletal muscle, eugenol (μM range) blocks excitation-contraction coupling. In skeletal muscle, however, larger doses of eugenol (mM range) induce calcium release from the sarcoplasmic reticulum. The effects of eugenol are therefore dependent on its concentration. In this study, we evaluated the effects of eugenol on the contractility of isolated, quiescent atrial trabeculae from male Wistar rats (250-300 g; n=131) and measured atrial ATP content. Eugenol (1, 3, 5, 7, and 10 mM) increased resting tension in a dose-dependent manner. Ryanodine [100 µM; a specific ryanodine receptor (RyR) blocker] and procaine (30 mM; a nonspecific RyR blocker) did not block the increased resting tension induced by eugenol regardless of whether extracellular calcium was present. The myosin-specific inhibitor 2,3-butanedione monoxime (BDM), however, reversed the increase in resting tension induced by eugenol. In Triton-skinned atrial trabeculae, in which all membranes were solubilized, eugenol did not change resting tension, maximum force produced, or the force vs pCa relationship (pCa=-log [Ca2+]). Given that eugenol reduced ATP concentration, the increase in resting tension observed in this study may have resulted from cooperative activation of cardiac thin filaments by strongly attached cross-bridges (rigor state).

Peripheral ossifying fibroma: A clinical and histological evaluation of 51 cases.

The present retrospective study was carried out to investigate the clinical and histological features of 51 cases of peripheral ossifying fibroma (POF). The clinical information such as age, sex, location, color of the lesion, pedunculated/ sessile was recorded. The lesion was found more frequently in females (62.75%) and 2nd decade. It had a predilection for the maxillary gingiva (68.63%) and the incisor/cuspid region (72.55%). The average age of occurrence was 38.5 years. Histologically, the surface epithelium was ulcerated in 15(29.41%) cases and in the rest, it was non-ulcerated. The lesion exhibited highly cellular fibroblastic tissue in 12(23.53%) cases, and in the remaining cases it showed more fibrous tissue. Mineralized products in the form of trabeculae of woven and/ or lamellar bone (61%), cementum like material (12%) and dystrophic calcification (27%) were noticed.

Evaluación de la miocardiopatía no compactada con resonancia magnética cardíaca en pacientes con función sistólica del ventrículo izquierdo conservada y disminuida / Evaluation of non-compaction cardiomyopathy with cardiac magnetic resonance imaging in patients with preserved and decreased left ventricular systolic function

Objective: Non-compaction cardiomyopathy (NCC) is a genetic disorder characterized by the presence of an extensive trabecular layer of myocardium with intertrabecular recesses in communication with the ventricular cavity. The objective of this study is to evaluate the clinical and morphological characteristics of patients with NCC with and without systolic dysfunction assessed by cardiac magnetic resonance (CMR) imaging, as well as to discuss the value and limitations of echocardiography and CMR imaging in its diagnosis. Twenty patients diagnosed with NCC were retrospectively included. Studies were performed on a 1.5 Tesla resonator. The end-diastolic volume (LVEDV) and end-systolic volumen (LVESV), end-diastolic diameter (LVEDD) and end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF), cardiac mass and LV trabeculations were determined. A 17-segment myocardium segmentation model was applied. Student s T test was used to compare variables between groups. Significance level was set at p <0.05. Correlation between 2 continuous variables was calculated using the linear regression model. The statistical software package used for data analysis was StatsDirect (Version 2.6.5,. Altrincham, UK. Results: The average thickness of NC myocardial segments and normal myocardium was 13.1 +/- 3.3 mm and 3.6 +/- 0.6 mm, respectively. The average number of myocardial segments with NC was 8.2 +/- 1.2. The more affected segments were the apex of the heart and the lateral segments at the apical and mid-ventricular level. LVEDD, LVEDV, global LV mass, compacted and trabeculated, were significantly increased in the group of patients with ventricular dysfunction. LVEF had a negative linear correlation with trabecular myocardal mass (MM)/ m2 (R = 0.67, p = 0.001), LVEDV /m2 (R = 0.77, p <0.001) and LVEDD/m2 (R = 0.7, p <0.001). Similarly, a negative linear correlation between LVTM/m² and LVEDV/m² (R = 0.76, p < 0.001) was observed. Conclusion: In our population...

Objetivos: La miocardiopatía no compactada (MNC) es un desorden genético caracterizado por la presencia de una extensa capa de miocardio trabeculado con recesos intertrabeculares comunicados con la cavidad ventricular. El objetivo del trabajo es evaluar las características clínicas y morfológicas de los pacientes con MNC con y sin disfunción sistólica evaluados por resonancia magnética cardíaca (RMC), y poner en discusión los alcances y las limitaciones de la ecocardiografía y la RMC en su diagnóstico. Material y métodos: Se incluyeron en forma retrospectiva 20 pacientes con diagnóstico de MNC. Los estudios se realizaron en un resonador de 1.5 Tesla. Se determinaron: volumen de fin de diástole (VFDVI) y sístole, diámetro de fin de diástole (DFDVI) y sístole, fracción de eyección (FEVI), masa cardíaca y trabeculaciones del VI. La distribución del miocardio NC se llevó a cabo con el modelo de 17 segmentos miocárdicos. Se empleó el test de Student para comparar las variables entre ambos grupos. El nivel de significancia fue establecido en p < 0,05. La correlación entre 2 variables continuas se calculó usando el modelo de regresión lineal. Los análisis se realizaron utilizando el software de estadística StatsDirect (versión 2.6.5, Altrincham, UK). Resultados: El espesor medio del miocardio NC y el miocardio normal fue 13.1 +/- 3.3 mm y 3.6 +/- 0.6 mm respectivamente. El número medio de segmentos con miocardio NC fue 8.2 +/- 1.2, siendo los más afectados el ápex y los segmentos laterales a nivel apical y medioventricular. El DFDVI, el VFDVI, la masa global, compactada y trabeculada del VI estuvieron incrementados en forma significativa en el grupo de pacientes con disfunción ventricular. La FEVI tuvo una correlación lineal negativa con masa de miocardio trabeculado del VI (MTVI)/m2 (R = 0.67, p = 0.001), el VFDVI/m2 (R = 0.77, p < 0.001) y el DFDVI/m2 (R = 0.7, p < 0.001). Asimismo, hubo una correlación lineal negativa entre la MTVI/m2 y el VFDVI/m2...

The effects of electromagnetic fields on osteoporosis in ovariectomized mice / 中华物理医学与康复杂志

Objective To study the effects of electromagnetic field (EMF) exposure on osteoporosis in ovariectomized mice. Methods Sixty 8-week-old female Kunming mice were divided into four groups at random: a sham operation group (group A), an ovariectomized group (group B), an EMF and ovariectomized group (group C) and a nilestriol and ovariectomized group (group D). Bilateral ovariectomies were performed on all mice except those in group A. The mice of group C were exposured to a 15 Hz, 1.0 mT electromagnetic field. The mice of group D were given at nilestriol 1.5 mg/kg/week. The bone mineral density (BMD) of the lumbar vertebrae was measured before the mice were sacrificed at the 12th week. Blood specimens were collected every two weeks to measure the ac-tivity of alkaline phosphatase (ALP) and the concentration of bone gamma-carboxyglutamic-acid-containing proteins (BGP), calcium and estradiol in the serum. Histological sections were taken to examine and analyze the changes in bone trabeculae in the lumbar vertebrae after 6 and 12 weeks. Results EMF at 15 Hz and 1.0 mT intensity signifi-cantly increased the activity of ALP and the concentrations of BGP and calcium in the serum. In addition, the absorp-tion of bone trabeculae in the lumbar vertebrae was significantly restrained. Conclusions EMF at 15 Hz and 1.0 mT can restrain the development of osteoporosis in ovariectomized mice.

Quiste subaracnoideo de médula espinal: a propósito de un caso. Hospital Dr. Roberto Gilbert Elizalde / Spinal subarachnoid cyst: case report. Dr. Roberto Gilbert Elizalde Hospital

Los quistes aracnoideos espinales son colecciones de líquido producidos por una alteración en las trabéculas aracnoideas, y son una causa muy infrecuente de compresión medular. Las etiologías de las compresiones medulares son extra e intradural. En el primer grupo dominan las metástasis vertebrales; y en el segundo, la etiología más frecuente está constituída por tumores benignos extramedulares, cuyo pronóstico es excelente si la intervención es oportuna. El diagnóstico y el tratamiento de las compresiones medulares se manifiestan como verdaderas urgencias, a las cuales debe darse una solución antes de la aparición de lesiones medulares irreversibles. Los quistes aracnoidales extradurales son lesiones expansivas poco frecuentes del canal espinal. Pueden manifestarse como radiculopatías, mieloradiculopatías o mielopatías lentamente progresivas y con poca frecuencia causan compresión medular sintomática. Hasta alrededor de los años setenta el tratamiento de elección en la fase inicial de las lesiones medulares era el conservador. Sin embargo, presentamos un caso clínico hospitalizado en el centro asistencial Dr. Roberto Gilbert Elizalde.

Spinal subarachnoid cysts are colections of liquid that develops from the abnormality of the arachnoid trabeculae. They are the rare cause of spinal compression. Spinal compression can be caused by extra or intradural tumors. Extradural tumors are metastatic tumors of the vertebrae. The intradural tumors are benign extramedullary tumors that are very common and have good prognosis. Diagnosis and treatment of spinal compression should be given before the spinal lesions are irreversible. Extradural arachnoid cyst are rare and are responsible of radiculopathies, mieloradiculopathies and mielopathies that is slowly progressive. We have a case admitted to the Dr. Roberto Gilbert Elizalde hospital.

Failure mode of depressive osteochondral fracture under maximum compressive load: Studies of normal, osteoporotic, and osteosclerotic subchondral bones.

Objective: To determine the failure mode of depressive osteochondral fracture under the maximum compressive load. Design: An experimental cadaveric study. A compressive load was applied through an indenter on a femoral condyle to create a depressive osteochondral fracture until the maximum load was reached. Background: Most depressive osteochondral fractures occur without a gross articular cartilage injury because a large amount of load is reabsorbed by the surrounding tissues, especially the subchondral bone under the cartilage. We asked what the mode of depressive osteochondral fracture is. It might function as a load adsorber from the articular cartilage. Methods: Three groups of depressive osteochondral fractures were studied. Croup 1 consisted of 12 pieces of middle third of normal median and lateral femoral condyles. Groups 2 and 3 consisted of 12 pieces of osteoporotic and osteosclerotic middle of both femoral condyles. Using a universal testing machine, a depressive osteochondral fracture was created by applying a uniaxial compressive load through an indenter until the load rose to the maximum level. At that point, the load applied was stopped in order to minimize the extent of subchondral trabeculae fracture. Maximum load was recorded. Pressure and stiffness were calculated. The pattern of depressive fracture was studied histologically. Results: The failure mode of depressive osteochondral fracture wan such that the bone under the articular cartilage had a subchondral plate fracture, an interlacing of bone trabeculae under the plate, and a few fractures of the bone trabeculae. The interlacing of subchondral bone trabeculae was most evident in the normal bone as compared with the osteoporotic and osteosclerotic bones. The osteosclerotic bone failed at the highest load, while the osteoporotic bone failed at the lowest. Conclusion: The subchondral plate fracture and the interlacing of subchondral bone trabeculae under the plate are the characteristics of the failure mode of depressive ostechondral fracture. This failure mode occurs before there is a discernible fracture of the subchondral bone trabeculae. The amount of load causing fracture depends on the quality of the bone. Relevance: The failure mode, especially the interlacing of subchondral bone trabeculae, night function as a load absorber from the articular cartilage. Therefore, the quality of subchondral bone is important for protection of the articular cartilage from compressive load injury.

Effect of Platelet-Rich Plasma on Bone Formation In Distracted Area of Canine Mandible

Distraction osteogenesis refers to the biological process responsible for new bone formation between bone segments by gradual distraction after osteotomy. For the past several years, various inconveniences including a protracted consolidation period that requires patients to wear a distractor frame longer, as well as higher medical costs, have not been remedied by improvements in osteotomy, distraction rate and monitoring system. Furthermore, side effects such as pin tract infections and soft tissue swelling may arise due to the long treatment period. These drawbacks form the rationale of this study which purports to seek a method by which the consolidation period can be reduced. This paper examines how platelet-rich plasma (PRP), known to facilitate osteogenesis, influences bone formation when applied in distracted area. Ten mongrel dogs, which were made to wear external distractor frames after osteotomy in both sides of the mandible, were used as subjects. After a 7day period of latency, distraction was carried out at a rate of 1mm/day for 14 consecutive days. After the onset of distraction, 2ml of PRP and a mixture of calcium gluconate and thrombine were injected into the center of the distracted callus on the left side of the mandible. The left was injected with PRP while the right side was set as the control site without PRP treatment. Execution at the onset of distraction and in 2 weeks, 4 weeks and 8 weeks after the consolidation period, clinical and radiographic tests, bone mineral density examination, histological examination and histomorphometric analysis were conducted to compare both sides. The results are summarized as follows: 1. Based on the clinical examination at two weeks, more remarkable cortical bone formation was found on the buccal and lingual side of the distracted area in the PRP treatment site than in the control site. No visual difference was found between the PRP treatment site and the control site at four and eight weeks. 2. Based on the radiological examination, a distinct increase in the radiopaque appearance of the PRP treatment site was revealed at two weeks, but this increase appeared to slow down at four and eight weeks. 3. Examination of bone mineral density revealed a significant difference at two weeks with the PRP treatment site yielding density two times higher than the control site. This difference lessened after four weeks, and disappeared at eight weeks. 4. The histomorphometric examination revealed that about 20% more bony trabeculae area (20% higher) was formed in the PRP treatment site than in the control site. In conclusion, it can be said that PRPs effect on stimulating bone formation in the PRP treatment site manifest as early as two weeks. Trabeculae formation likewise increased throughout the whole period. If this result can be applied to humans, the consolidation period can be reduced by injecting PRP into the distracted area.

Effect of Caffeine on Calcium Flux across the Sarcolemma of Guinea Pig Atrial Trabeculae during Contracture

The changes in extracellular calcium activities during contractures of guinea pig atrial trabecular muscles were measured with Ca2+-selective electrodes. When the tissue was superfused with Na+-free Tyrode solution extracellular Ca2+ activities were decreased and contractures were induced with some delay. When the contracture was relaxed with Na+-containing Tyrode solution, extracellular Ca2+ activities were increased transiently and recovered in a Na+-dependent manner. The magnitude of extracellular Ca2+ activity decreased was proportional to the maximum magnitude of contracture induced by Na+-free solution. Addition of caffeine (10 mM) to Na+-free solution induced transient contracture following slow development of contracture and an increase in extracellular Ca2+ activity. Removal of caffeine from Na+-free solution caused a slow relaxation of contracture and a decrease in extracellular Ca2+ activity. These results confirm that caffeine blocks Ca2+ uptake by the sarcoplasmic reticulum (SR) resulting in an increase in sarcoplasmic Ca2+ activity. Ca2+ activity in the extracellular space, the amount of Ca2+ transported into the cell(Ca2+ depletion in the extracellular space), and the magnitude of contracture are well correlated. Present experiments suggest that extracellular use of Ca2+-selective electrodes provides continuous and quantitative monitoring of Na+-dependent Ca2+ flux across the cardiac cell membrane.