Biomedical subjects

Wei-Ming Chen

Publications and source records attributed to Wei-Ming Chen.

At least 19 recordsLinked to original sources

PubMed2006

Superficial soft-tissue lymphoma: sonographic appearance and early survival.

We evaluated superficial soft-tissue lymphomas on high-resolution ultrasonography (HRUS) in 43 patients (17 women, 26 men; mean, 59.7 y; range, 12 to 90 y), with 1- to 97-month follow-up. Clinical presentations, tumor location and morphology, echogenicity on HRUS and color-encoding grades on Doppler ultrasonography (CDUS) were assessed. Clinical presentations did not significantly differ with tumor location or morphology. Types of lymphoma did not significantly differ in echogenicity, although most were hypoechogenic. On CDUS, most lymphomas were hypervascular, but grades did not significantly depend on the type of tumor. On Kaplan-Meier analysis with log-rank testing, survival did not differ by age (divided at 65 y), sex, tumor location or size (cut-off, 5 cm), CDUS grade or pathology. Survival was significantly related to clinical presentation (p < 0.0095) and tumor morphology (p < 0.0354). HRUS and CDUS were good modalities to detect the masses and provided important pretreatment information.

Adolescent↗

PubMed2005

Type II collagen gene variants and inherited osteonecrosis of the femoral head.

BACKGROUND: Avascular necrosis of the femoral head (ANFH) causes disability that often requires surgical intervention. Most cases of ANFH are sporadic, but we identified three families in which there was autosomal dominant inheritance of the disease and mapped the chromosomal position of the gene to 12q13. METHODS: We carried out haplotype analysis in the families, selected candidate genes from the critical interval for ANFH on 12q13, and sequenced the promoter and exonic regions of the type II collagen gene (COL2A1) from persons with inherited and sporadic forms of ANFH. RESULTS: We identified a G-->A transition in exon 50 of COL2A1 in affected members of a four-generation family with ANFH. This transition predicts the replacement of glycine with serine at codon 1170 in a GXY repeat of type II collagen. Another pedigree was shown to harbor the same transition, but the mutant allele occurred on a different haplotype background. In a third family, a G-->A transition in exon 33 of the gene, causing a glycine-to-serine change at codon 717, was detected. No mutation was found in the COL2A1 coding region in sporadic cases of ANFH. CONCLUSIONS: All the patients with familial ANFH whom we studied carried COL2A1 mutations. In families with ANFH, haplotype and sequence analysis of the COL2A1 gene can be used to identify carriers of the mutant allele before the onset of clinical symptoms, allowing the initiation of measures that may delay progression of the disease.

Adult↗

PubMed2005

Giant cell tumors of the knee: subchondral bone integrity affects the outcome.

From January 1992 to July 2001, we treated 38 patients with giant cell tumour in the knee region. Seventeen tumours were located in the distal femur and 21 in the proximal tibia . Twenty patients were classified as Campanacci grade II, 15 as grade III, and three as grade I. Patients' mean age was 34.5 (19-65) years, and the mean follow-up was 52 (24-134) months. Operative procedures were chosen according to the extent of bone and soft-tissue involvement. In 28 patients, intralesional curettage and bone grafting was performed and in ten patients a wide resection. We defined subchondral bone of the knee to be affected when the distance to the tumour was less than 3 mm. We then measured the area of affected subchondral bone radiographically using plain radiographs, CT, and MRI. In patients initially treated with curettage and bone grafting, the mean area of initially affected subchondral bone was 18.6 (0-81)%. The mean Enneking functional score at follow-up was 88 (66.6-100). There was a linear trend showing that the larger the area of affected subchondral bone, the worse the functional score. Among patients initially treated with wide resection, the mean area of affected subchondral bone was 68.2 (41-100)%. There was, however, no significant association between affected subchondral bone area and functional score.

Adult↗

PubMed2005

Central corneal mosaic opacities in Schnyder's crystalline dystrophy.

PURPOSE: To report an unusual presentation of Schnyder's corneal crystalline dystrophy (SCCD), sharing the feature of central corneal mosaic opacities. DESIGN: Observational case report. METHODS: A 51-year-old man and his family members were examined. Investigations included slit-lamp biomicroscopy, radiography of knee joint, plasma lipid level, and genotyping of the SCCD candidate region in chromosome 1p34.1-1p36. RESULTS: A symmetric, central, disciform, full-thickness opacity was seen in both corneas of the patient. The opacities appeared in a mosaic pattern, instead of collections of crystals or a diffuse haze as typically detected in SCCD. Small clumps of crystalline deposits and arcus lipoides were also observed. Systemically, hyperlipidemia and bilateral genu valgus were identified. He had 2 daughters, and both of them had bilateral corneal crystalline deposits and genu valgus. No other family members had findings suggesting SCCD. The genetic study demonstrated that all of the affected individuals shared a common haplotype within the region of previously reported SCCD locus. However, 1 unaffected sibling of the proband also had the same haplotype. CONCLUSIONS: Central corneal mosaic opacities may be another variant of SCCD.

Adolescent↗

PubMed2005

3-D ultrasound texture classification using run difference matrix.

Ultrasonography is one of the most useful diagnostic tools for human soft tissue and it is in routine use in nearly all hospitals and many physicians' offices and clinics. However, the diagnosis mostly depends upon the personal experiences of the physicians. Moreover, the surface features and internal architecture of a tumor are not easy to be demonstrated simultaneously using the conventional two-dimensional (2-D) ultrasound. Recently, three-dimensional (3-D) ultrasound has been developed and allows the physician to view the 3-D anatomy. 3-D breast US can provide transverse, longitudinal planes as well as in addition simultaneously the coronal plane. This additional information has been proved to be helpful for clinical applications. In this paper, a new approach of texture classification of 3-D ultrasound breast diagnosis using run difference matrix with neural networks is developed. The test 3-D US image database includes 54 malignant and 161 benign tumors. In the experiments, the area index A(z) under the ROC curve of the proposal 3-D RDM method can achieve 0.9680. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value of the proposed 3-D RDM method is 91.9%(148/161), 88.9%(48/54), 93.5%(100/107), 87.3%(48/55), and 94.3%(100/105), respectively.

Area Under Curve↗

PubMed2005

Extraosseous osteogenic sarcoma.

Extraosseous osteogenic sarcoma is a very rare malignant neoplasm. Out of the more than 400 cases of soft tissue sarcomas on file in our hospital, only 2 were extraosseous osteogenic sarcomas. Both were situated in the thigh. The first case was initially diagnosed as a hematoma and treated by marginal excision. The diagnosis of high-grade osteosarcoma primarily arising in soft tissue was made from histopathologic examination. Radiotherapy of 60 Gy in 30 fractions was given postoperatively. The second patient, primarily diagnosed as having a soft tissue sarcoma, was treated by wide excision. The final pathologic report was high-grade extraosseous osteogenic sarcoma. Adjuvant chemotherapy was given postoperatively. Both patients are alive without local recurrence and distant metastasis at postoperative 90-month and 107-month follow-up, respectively.

Aged↗

PubMed2005

Orbital metastatic osteosarcoma.

A 15-year-old girl with right tibial osteosarcoma, diagnosed 22 months previously, developed right orbital and skull base metastases, with symptoms including painful protrusion of the right eyeball and severe visual impairment. She underwent embolization of the metastatic tumor, local irradiation, and chemotherapy followed by intralesional resection of the mass because extensive involvement of the skull base precluded complete surgical resection. The best corrected visual acuity in her right eye initially decreased to 20/200, then dropped to no light perception after embolization, and then improved to counting fingers at 50 cm after radiotherapy. The symptoms of pain and proptosis subsided completely. After 24 months of follow-up from the presentation of orbital metastasis, the patient's right-eye vision remained unchanged. The surgical specimen revealed a necrotic tumor similar to osteosarcoma. In conclusion, orbital metastasis of osteosarcoma is rare, but may lead to severe visual impairment. Combined radiotherapy, chemotherapy and surgery can partially relieve symptoms, but cannot completely eradicate the tumors.

Adolescent↗

PubMed2005

Allograft arthrodesis of the knee in high-grade osteosarcoma.

BACKGROUND: A retrospective cohort study was conducted to evaluate the outcomes of massive allograft arthrodesis in the management of high-grade osteosarcoma around the knee. METHODS: The results of 19 patients with high-grade osteosarcoma around the knee, which was treated by wide resection and reconstruction using allograft arthrodesis, were evaluated for a mean length of 7.3 years (range, 3-13 years). The mean age at the time of surgery was 13.3 years (range, 6-27 years). According to the Musculoskeletal Tumor Society staging system, 17 patients were stage IIB and 2 were stage IIIB at presentation. Evaluations were based on the oncologic results, non-oncologic results and complications. Functional evaluation was performed with the Enneking functional evaluation form. RESULTS: Four patients (21.1%) died of their disease; 3 (15.8%) are alive with disease; and 12 (63.2%) are free of disease. Four patients (21.1%) had local recurrence of their tumor at a mean of 23 months postoperatively (range, 9-44 months). The mean time to union of the metaphyseal junction was 24.7 weeks (range, 16-30 weeks) and the diaphyseal junction was 47 weeks (range, 24-78 weeks). The overall complication rate was 31.6%, including 2 (10.5%) infections, 3 (15.8%) allograft fractures, and 1 (5.3%) nonunion. Our mean final functional result was 65%. CONCLUSION: Due to the high rate of complications in this study, we conclude that allograft arthrodesis should be left as a salvage or "back-up" reconstructive procedure after resection of osteosarcoma around the knee, unless there are special indications for this procedure. We found allograft fracture to be the most common complication.

Adolescent↗

PubMed2005

Shepherd's crook deformity of polyostotic fibrous dysplasia treated with corrective osteotomy and dynamic hip screw.

Fibrous dysplasia, a condition in which the skeleton fails to develop normally, is characterized by fibroblastic stroma and immature bone. Bowing of the long bones occurs frequently in the polyostotic form, and stress fractures often result. Shepherd's crook deformity is a characteristic feature of fibrous dysplasia. The goal of its treatment is to obtain normal walking ability and relieve pain due to pathologic fracture secondary to the deformity; however, correction of the deformity is a surgical challenge. We present 2 cases of shepherd's crook deformity treated with corrective osteotomy and a dynamic hip screw. Both cases showed good bone healing and no recurrent deformity. The gross deformities were corrected, and both patients were pain-free after operation.

Adult↗

PubMed2005

Preoperative tibiofemoral angle predicts survival of proximal tibia osteotomy.

A prospective group study was done to clarify whether perioperative variables such as preoperative and postoperative tibiofemoral angles influence the survivorship of proximal tibia osteotomy as measured by conversion to arthroplasty and patient dissatisfaction. The results of 93 proximal tibial osteotomies in 82 consecutive patients with medial compartment osteoarthrosis were followed up for a mean of 10.9 years. All data were analyzed by the Kaplan-Meier survivorship method and the multivariate Cox proportional hazards model. Only the preoperative tibiofemoral angle was a predictor of conversion to arthroplasty and patient dissatisfaction. The ideal prognostic cutoff angle was 9 degrees or less varus. Increasing the preoperative varus alignment 1 degrees would result in a 1.2 (95% confidence intervals, 1.02-1.50) times higher risk of conversion to a total knee arthroplasty and a 1.5 (95% confidence intervals, 1.27-1.76) times higher chance of patient dissatisfaction. Factors such as age, gender, body mass index, Ahlback's classification, and postoperative tibiofemoral angle were not significant. We think that proximal tibial osteotomy should be considered for patients with medial compartment osteoarthrosis and a preoperative varus alignment of 9 degrees or less, whereas arthroplasty is a more suitable alternative for patients with preoperative varus alignment greater than 9 degrees.

Adult↗

PubMed2005

High-resolution ultrasonography of primary peripheral soft tissue lymphoma.

OBJECTIVE: The purpose of this study was to evaluate the appearance of primary peripheral soft tissue lymphoma on high-resolution ultrasonography. METHODS: We retrospectively studied the sonograms of 12 patients (5 female and 7 male; age range, 12-90 years; mean, 55 years) with soft tissue lymphoma. All lesions were palpable and in the salivary glands, trunk, upper limb, or lower limb, and the diagnosis was proved by biopsy or open surgery. For each lesion, sonograms were obtained by gray scale and color Doppler ultrasonography. RESULTS: The gray scale imaging showed relatively homogeneous hypoechogenicity in 11 patients and homogeneous hyperechogenicity in 1 patient. The tumors appeared as big masses in 5 patients, nodal or confluent nodes in 3, small disseminated nodules in 2, a myositis type in 1, and a panniculitis type (homogeneous echogenic infiltrate in a subcutaneous fat layer) in 1. CONCLUSIONS: In patients with a soft-tissue mass, routine plain radiography and high-resolution ultrasonography including color Doppler ultrasonography are recommended before further evaluation with ultrasonographically guided biopsy.

Adolescent↗

PubMed2004

Fluvastatin and lovastatin but not pravastatin induce neuroglial differentiation in human mesenchymal stem cells.

Recent studies have shown that statins, the most potent inhibitors of 3-hydroxy-2-methylglutaryl coenzyme A (HMG-CoA) reductase, stimulate bone formation in vitro and in rodents by activating the expression of bone morphogenetic protein-2 (BMP-2), one of the most critical osteoblast differentiation-inducing factors. However, the effect of statins on mesenchymal stem cells (MSCs) is yet to be reported. The purpose of this study is to investigate the influence of fluvastatin, lovastatin, and pravastatin, three commonly prescribed lipid-lowering agents, on the proliferation and differentiation of human MSCs. To our surprise, even though fluvastatin and lovastatin effectively suppressed the growth of human MSCs, a neuroglia rather than osteoblast-like morphology was observed after treatment. Interestingly, such morphological change was inhibited by the co-addition of geranylgeranyl pyrophosphate (GGPP). Immunofluorescence staining with antibodies against neuron-, astrocyte-, as well as oligodendrocyte-specific markers confirmed the neuroglial identity of the differentiated cells. However, BMP-2 is unlikely to play a positive role in neuroglial differentiation of MSCs since its expression was down-regulated in fluvastatin-treated cells. Taken together, our results suggest that fluvastatin and lovastatin induce neuroglial differentiation of human MSCs and that these cholesterol-lowering agents might be used in conjunction with MSC transplantation in the future for treating neurological disorders and injuries.

Antineoplastic Agents↗

PubMed2004

Autosomal dominant avascular necrosis of femoral head in two Taiwanese pedigrees and linkage to chromosome 12q13.

Avascular necrosis of the femoral head (ANFH) is a debilitating disease that commonly leads to destruction of the hip joint in adults. The etiology of ANFH is unknown, but previous studies have indicated that heritable thrombophilia (increased tendency to form thrombi) and hypofibrinolysis (reduced ability to lyse thrombi), alcohol intake, and steroid use are risk factors for ANFH. We recently identified two families with ANFH showing autosomal dominant inheritance. By applying linkage analysis to a four-generation pedigree, we excluded linkage between the family and three genes related to thrombophilia and hypofibrinolysis: protein C, protein S, and plasminogen activator inhibitor. Furthermore, by a genomewide scan, a significant two-point LOD score of 3.45 (recombination fraction [theta] = 0) was obtained between the family with ANFH and marker D12S85 on chromosome 12. High-resolution mapping was conducted in a second family with ANFH and replicated the linkage to D12S368 (pedigree I: LOD score 2.47, theta = 0.05; pedigree II: LOD score 2.81, theta = 0.10). When an age-dependent-penetrance model was applied, the combined multipoint LOD score was 6.43 between D12S1663 and D12S85. Thus, we mapped the candidate gene for autosomal dominant ANFH to a 15-cM region between D12S1663 and D12S1632 on chromosome 12q13.

Adolescent↗

PubMed2004

Giant-cell tumors of bone: an analysis of 87 cases.

We reviewed 87 patients with giant-cell tumor treated between 1992 and 2001. The mean follow-up was 62 (28-138) months. Fifty-six lesions were treated with intralesional curettage with adjunctive phenol treatment and reconstructed with autograft and allograft. Thirty-one lesions were treated with wide resection and reconstructed with prosthesis, osteochondral allograft, or alloprosthetic composite. Overall recurrence was 12%. Recurrence rate after curettage was 18% and 3% after wide excision. Complication rate after wide excision was higher than that after curettage. Functional outcome was evaluated using the Enneking scoring system. Average rating was 86% for the lower extremity and 83% for the upper extremity. The overall satisfactory rate was 88%.

Adolescent↗

PubMed2004

Advanced osteoarthritic knee with neglected patellar tendon rupture treated with total patellectomy and total knee arthroplasty.

Loss of the knee extensor mechanism results in a change of normal knee joint alignment and functional anteroposterior instability. In patients with neglected or chronic patellar tendon rupture, advanced degenerative change of the knee joints may develop at the later stage. We present a case of a 64-year-old man with chronic left patellar tendon rupture and 10-cm proximal patella migration associated with advanced osteoarthritis of the knee. Total patellectomy and simultaneous total knee arthroplasty (TKA) relieved his symptoms and disability successfully. His left knee still did well at 7-year follow-up.

Accidental Falls↗

PubMed2004

Fracture of the polyethylene tibial post in a NexGen posterior-stabilized knee prosthesis.

We reported a case of fracture of a polyethylene tibial post in a 44-year-old woman after 3 years of NexGen posterior-stabilized total knee arthroplasty (Zimmer, Warsaw, IN). Burnishing and delamination of the polyethylene was found around the breakage site of the post, especially over the anterior aspect of the post base. It indicated that the possible failure mechanism was the repeated anterior impingement between the metal femoral cam and polyethylene tibial post. After replacement of the broken insert, the patient obtained complete relief of previous symptoms. To our knowledge, this is the first report of post breakage of a NexGen posterior-stabilized knee prosthesis.

Adult↗

PubMed2004

Bilateral proximal tibial stress fractures in osteoarthritic knee treated with simultaneous corrective osteotomy and internal fixation.

We report a patient who had bilateral stress fractures of proximal tibial shaft secondary to advanced osteoarthritis of knee with varus deformity. With treatment by simultaneous correction of deformity and internal fixation, the fractures healed uneventfully and the chronic knee pain was much alleviated. Due to progression of the symptom, right total knee replacement was finally performed 9 years later. Her left knee still did well after 13-year follow-up.

Aged↗

PubMed2004

Huge aneurysmal bone cyst of iliac bone in a mid-aged female.

Aneurysmal bone cyst is a rare nonneoplastic expansile osteolytic bone lesion of unknown etiology. It usually occurs in the first 2 decades of life. The most common sites are the metaphysio-epiphyseal areas of long bones or vertebrae with eccentric expansion. We present a 42-year-old female with a huge aneurysmal bone cyst of the pelvis with dumbbell-shaped expansion on the both side of the iliac bone, which grew rapidly in 6 months. We also review the literature and discuss its prevalence, clinicopathologic characteristics, differential diagnostic problems, optimal treatment, and the potential of recurrence.

Adult↗