Myiasis is most prevalent in Mexico, central and south America, tropical Africa, and the southwestern United States. Although dermal myiasis is rare in most of the United States, it is a disorder that may be seen in international travelers. In the United States, external myiasis is usually caused by the cattle botfly. We report here a case of ophthalmomyiasis involving the left upper eyelid of a child. We examined a six-year-old boy who presented to the Massachusetts Eye and Ear Infirmary (MEEI) in September 1998. He complained of persistent swelling of his left upper eyelid for the previous ten days. The edema and erythema were unresponsive to warm compresses and oral antibiotics. Ocular examination revealed a mild preseptal cellulitis of the left upper eyelid with a small draining fistula. On slit-lamp examination, we found one larva protruding intermittently from the fistula site. The larva was extracted with forceps, wrapped in a moist towel and sent in a jar to the parasitology laboratory. The specimen was identified as a Cuterebra larva by a parasitologist at the Harvard School of Public Health. One week later, the patient's eyelid edema and erythema had completely resolved.
Animal ; Case Report ; Child ; Diagnosis, Differential ; Diptera* ; Eye Infections, Parasitic*/surgery ; Eye Infections, Parasitic*/parasitology ; Eye Infections, Parasitic*/diagnosis ; Eyelid Diseases/surgery ; Eyelid Diseases/parasitology* ; Eyelid Diseases/diagnosis ; Eyelids/parasitology* ; Human ; Larva ; Male ; Myiasis*/surgery ; Myiasis*/parasitology ; Myiasis*/diagnosis

Many operative procedures for osteonecrosis of the femoral head(ONFH) have been proposed, but their clinical results remain controversial to many clinicians. Recently, a new surgical procedure that incorporates cementation with polymethylmethacrylate(PMMA) after core drilling has been tried clinically. In this study, a finite element method (FEM) was employed to analyze and compare various surgical procedures of ONFH to provide a biomechanical insight by varying physiological loading conditions. Our finite element models were constructed for this purpose they included normal, necrotic, core decompressed, fibular bone grafted, and cementation models. The extent of necrotic region was determined based upon the average CT-scan data from 10 patients. The physiological load directions and magnitudes during the gait cycle were selected at the stage of heel-strike, toe-off, and average stance. The von Mises stresses were calculated and volumetric percentages of the necrotic region under different levels of stresses were analyzed for each model. Our results indicated that there were substantial increase of the necrotic region subjected to the high stress level (beyond 11 MPa) and decrease in the low stress level (below 5 MPa) with the core decompression model, an indication of a malignant stress transfer pattern. On the other hand, the exact opposite pattern of stress transfer was noted with the fibular bone graft and cementation methods suggesting that they could provide structural integrity within the necrotic region.
Cementation ; Decompression ; Gait ; Hand ; Head* ; Humans ; Osteonecrosis* ; Surgical Procedures, Operative ; Transplants

PURPOSE: The effects of fiber alignment and direction of mechanical strain on the ECM generation of human ACL fibroblast were assessed. MATERIALS AND METHODS: The aligned nanofiber was fabricated using electrospinning with a rotating target. The amounts of collagen on aligned and randomly oriented structures were compared. To evaluate the effect of strain direction, 5% uniaxial strain (0.2 Hz) was applied to fibroblasts seeded on parallel aligned, vertically aligned to the strain direction, and randomly oriented nanofiber sheets. The amounts of collagen produced were measured 2 days after halting the strain application. RESULTS: The fibroblasts on the aligned nanofiber were spindle-shaped and oriented in the direction of the fibers. Significantly more collagen (22.5+/-2.7 ug/ngDNA) was synthesized on the aligned nanofiber than the randomly oriented (14.5+/-3.2 ug/ngDNA). And the amounts of collagen produced were increased by 150% and 50% approximately with the longitudinal and perpendicular cyclic strain, respectively. CONCLUSION: The aligned nanofiber scaffold used in this study constitutes a promising base material for tissue-engineered ligament in that it provides a more biomimetic structure, including the preferable mechanical environment.
Biomimetics ; Collagen ; Fibroblasts* ; Humans* ; Ligaments ; Nanofibers*

Recent studies suggest that addition of transfixators to pedicle screw instrumentation enhances rotational stability of the constructs. However, the effectiveness of the transfixators along with their ideal numbers and positions still remains unclear. In this study, finite element analysis was performed to suggest the most effective positions of the transfixators based on their numbers. For this purpose, a finite element model of a spinal segment(L3-5) with total vertebrectomy at L4 and pedicle screw instrumentation was developed. The finite element model was made with 3-D 8 node solid elements so that they are more realistic and closer to the actual human vertebrae than the preciously published models. On this model, the transfixator(s) were placed along the pre-determined position(s) along the rod while its number was varied between 1 and 2. Appropriate boundary conditions were designated and rotational moment of 6.4 Nm was applied both in axial rotation and lateral bending. Improvement in rotational stability due to addition of the transfixator(s) was calculated as the percent decrease in motion relative to the case without. Results suggested that with one transfixator the rotational stability increased by the average of 19.0% and 6.1% against axial rotation and lateral bending, respectively. With two, the corresponding improvements were 32.3% and 10.7%. Against axial rotation, it was most effective when transfixator was placed at the middle of the rod(22.9%) for one transfixator and at the 1/3 and 2/3 sites along the rod(35.8%) for two. Against lateral bending, the ideal position(s) were at the proximal end(10.7%) for one transfixator and at the proximal and distal ends of the construct(17.7%) for two. It was also found that adding of a transfixator was more sensitive against lateral bending than against axial rotation(78% versus 64%). In conclusion, base on our biomechanical results, it can be suggested that the ideal positions for the ators are located at the equidistance from the both ends of the rod against axial rotation and at the both ends against lateral bending.
Finite Element Analysis* ; Humans ; Spine

PURPOSE: In this study, we investigated the potential of injectable hydrogel scaffolds for the regeneration of nucleus pulposus. MATERIALS AND METHODS: We prepared injectable hydrogels [Chitosan-Pluronic (CP), CP/Osteogenic Protein-1 (CP/OP-1), CP/Gly-Arg-Gly-Asp-Ser (CP/GRGDS), CP/GRGDS/OP-1] for this study. One of the four potential materials was selected through the cell viability tests. For each material, primary cultured nucleus pulposus (NP) cells from New Zealand rabbits were seeded onto each material. For the investigation of the effects of mechanical stimulation, the commercially available bioreactor was used. 0.2 MPa of intermittent hydrostatic pressure was imposed for 3 days after 7th day of seeding with the pattern of 2 min and 15 min for stimulating and resting, respectively. The specimens were harvested at 1, 10, 14 day after seeding for analyses. RESULTS: The MTT assay for 5 days revealed that CP/OP-1 group showed significant increase. The other two groups (CP/GRGDS and CP/GRGDS/OP-1) showed that the proliferation rate increased until 3 days after culture, while it decreased on day 5. The mechanical stimuli induced higher amounts of DNA measured in CP/OP- 1 on day 5 after culture. However, no significant difference was observed between two groups. CONCLUSION: We came to the conclusions that the biochemical environment as well as mechanical stimulation may play an important role in regenerating nucleus pulposus matrix, especially in CP/OP-1 in this study. However, further study are recommended in relation to mechanical effects as well as biochemical conditions.
Bioreactors ; Cell Survival ; DNA ; Hydrogel ; Hydrogels ; Hydrostatic Pressure ; Intervertebral Disc ; Porphyrins ; Rabbits ; Regeneration ; Seeds

This study proposed a mechanical model of the excimer laser photorefractive keratectomy(PRK) for myopia patients utilizing finite element method, which is a simulation technique widely used in engineering fields. The outcomes of the surgery depends on many factors, which are also dependent on each other. In this study, some mechanical factors are selected and the effects of the selected factors on the surgical results were analyzed. One of the important factors in the finite element analysis is the mechanical properties of the object. The representative characteristic of the human cornea is that it shows highly nonlinear property in the stress-strain relationship like most soft tissues in the human body. Therefore, the nonliear property was adopted in this study. Other important mechanical properties which affect the outcomes of the surgery are: a preoperative thickness, intraocular pressure, diameter of ablation zone and the depth of ablation. With various changes of the those mechanical factors, the outcomes of the surgery were predicted using the finite element method. The results show the qualitative agreement with clinical outcomes also promising agreement quantitatively. Therefore, this study shows a potential of the finite element method in clinical application of excimer laser PRK.
Cornea ; Finite Element Analysis ; Human Body ; Humans ; Intraocular Pressure ; Lasers, Excimer* ; Myopia ; Photorefractive Keratectomy*

The purpose of this study is to devlop the basic algorithm for the finite slsment method modeling of indivdual malocclusions. Usully, a great deal of time js spent in preprocessiong. To reduce the time required, we developed a stsndardized proccrdure for measuring the position of each tooth and a program to automatically preprocess. The following procedures were carride to complete this study. 1. Twenty-eigth teeth mofphologies were constructed three- dimensionally for the finite element analysis and saved as separate files. 2. Standard brackets were attached so that the FA points conincide with the center of the brackets. 3. The study model of a patient was made. 4. Using the study model, the crown inclination, and the vertical distance from the tip of a tooth was measured by using specially designed tools. 5. The arch form was determined from a picture of the model with an image processing technique. 6. The meadured data were input as a rotational matrix. 7. The program provides an output file containing the necessary information about the three-dimensional position of teeth, which is applicable to several finite element programs commonly used. The program for basic algorithm was made with Turbo-C and the subsequent outfile was applied to ANSYS. This standatdized model measuring procedure and the program reduce the time required, espccially for preprocessing and can be applied to other malocclusions easily.
Crowns ; Finite Element Analysis ; Humans ; Malocclusion* ; Tooth

Background: Hematopoietic stem/progenitor cells (HSPCs) have the property to return to the bone marrow, which is believed to be critical in situations such as HSPC transplantation. This property plays an important role in the stemness, viability, and proliferation of HSPCs, also. However, most in vitro models so far have not sufficiently simulated the complicate environment. Here, we proposed a three-dimensional experimental platform for the quantitative study of the migration of HSPCs. Methods: After encapsulating osteoblasts (OBs) in alginate beads, we quantified the migration of HSPCs into the beads due to the physical environment using digital image processing. Intermittent hydrostatic pressure (IHP) was used to mimic the mechanical environment of human bone marrow without using any biochemical factors. The expression of stromal cell-derived factor 1 (SDF-1) under IHP was measured. Results: The results showed that the presence of OBs in the hydrogel scaffold initiate the movement of HSPCs. Furthermore, the IHP promotes the migration of HSPCs, even without the addition of any biochemical factors, and the results were confirmed by measuring SDF-1 levels. Conclusion We believe this suggested three-dimensional experimental platform consisting of a simulated in vivo physical environment and encapsulated OBs should contribute to in vitro migration studies used to investigate the effects of other external factors.

Background: Hematopoietic stem/progenitor cells (HSPCs) have the property to return to the bone marrow, which is believed to be critical in situations such as HSPC transplantation. This property plays an important role in the stemness, viability, and proliferation of HSPCs, also. However, most in vitro models so far have not sufficiently simulated the complicate environment. Here, we proposed a three-dimensional experimental platform for the quantitative study of the migration of HSPCs. Methods: After encapsulating osteoblasts (OBs) in alginate beads, we quantified the migration of HSPCs into the beads due to the physical environment using digital image processing. Intermittent hydrostatic pressure (IHP) was used to mimic the mechanical environment of human bone marrow without using any biochemical factors. The expression of stromal cell-derived factor 1 (SDF-1) under IHP was measured. Results: The results showed that the presence of OBs in the hydrogel scaffold initiate the movement of HSPCs. Furthermore, the IHP promotes the migration of HSPCs, even without the addition of any biochemical factors, and the results were confirmed by measuring SDF-1 levels. Conclusion We believe this suggested three-dimensional experimental platform consisting of a simulated in vivo physical environment and encapsulated OBs should contribute to in vitro migration studies used to investigate the effects of other external factors.

Objective: The endothelial inflammatory response plays an important role in atherogenesis by inducing nuclear factor (NF)κB-dependent cell adhesion molecule expression and monocyte recruitment. Here, we screened for natural ligands and investigated the ability of shinjulactone A to inhibit interleukin-1β (IL-1β)-induced endothelial inflammatory signaling. Methods: The natural compound library included 880 single compounds isolated from medicinal plants by the Korean Medicinal Material Bank. Primary endothelial cells were pretreated with single compounds before stimulation with IL-1β to induce endothelial inflammation. Endothelial inflammation was measured by assaying NFκB activation and monocyte adhesion. The endothelial-mesenchymal transition (EndMT) was evaluated using cell type-specific marker protein expression and morphology. Results: Shinjulactone A was identified as an efficient blocker of IL-1β -induced NFκB activation, with a half-maximal inhibitory concentration of approximately 1 µM, and monocyte recruitment in endothelial cells. However, it did not affect lipopolysaccharideinduced NFκB activation in macrophages. Compared to Bay 11-782, a well-known NFκB inhibitor that shows considerable cytotoxicity during long-term treatment, shinjulactone A did not affect endothelial cell viability. Furthermore, it also significantly inhibited the EndMT, which is known to promote atherosclerosis and plaque instability. Conclusion We suggest that shinjulactone A may be an effective and safe drug candidate for atherosclerosis because it targets and inhibits both endothelial inflammation and the EndMT, without impairing NFκB-dependent innate immunity in macrophages.