Search PubMed⌕ Search

Biomedical subjects

T M Chen

Publications and source records attributed to T M Chen.

At least 19 recordsLinked to original sources
PubMed2004

Free thoracodorsal artery perforator flap in extremity reconstruction: 12 cases.

The need for thin flap coverage has increased, especially for contouring or covering shallow defects of extremities. The free thoracodorsal artery perforator flap harvested from the upper lateral back can be useful for this purpose. The thoracodorsal artery supplies the latissimus dorsi muscle and supplies perforating branches to the overlying skin. The flap is based upon the proximal perforator of the thoracodorsal artery, which usually emerges in an area approximately 8-10 cm below the posterior axillary fold and 2-3 cm posterior to the lateral border of the latissimus dorsi muscle. Between February of 2001 and April of 2003, we used the free thoracodorsal artery perforator flap for distal limbs reconstruction in 12 clinical cases, including three hands, two forearms and seven feet. The soft tissue defects resulted from trauma, scar release, chronic ulcer, or tumour ablation. The main advantages of the thoracodorsal artery perforator flap are that it contains no muscle, allowing more reconstructive precision, and morbidity is minimised by preserving the function of the latissimus dorsi muscle and hiding the donor scar. However, meticulous intra-muscular retrograde dissection of the perforator, to the thoracodorsal artery, is necessary in order to obtain suitable pedicle length and vessel diameter. The authors conclude that the free thoracodorsal artery perforator flap has greater potential for resurfacing large defects of distal limbs, because of its suitable thickness and hidden donor site.

Adult↗
PubMed2003

Prevalence and clinical implications of hepatitis B virus genotypes in southern Taiwan.

BACKGROUND: Hepatitis B virus (HBV) infection is a major health problem. HBV genotypes may be associated with progression of liver disease. The distribution and clinical implications of HBV genotypes in southern Taiwan are evaluated. METHODS: We used a polymerase chain reaction-restriction fragment length polymorphism genotyping method to determine HBV genotypes. RESULTS: The genotype distribution for 265 patients with chronic HBV infection was as follows: A, 3 (1%); B, 158 (60%); C, 90 (34%); D, 7 (2.5%); E, 0: F, 0; and unclassified, 7 (2.5%). Compared with genotype B patients, genotype C patients had a higher hepatitis B e antigen positive rate and higher fibrosis score. There was no significant difference in the mean age between genotype B and genotype C patients with hepatocellular carcinoma (HCC). However, when patients were stratified by age, the prevalence of genotype C was significantly higher in young HCC patients (<50 years of age) than in age-matched asymptomatic carriers (40% versus 10%, P < 0.001). Using multivariate analysis, the significant risk factors for advanced liver disease (cirrhosis or HCC) for patients with chronic HBV infection were old age, male gender and genotype C. CONCLUSIONS: These results suggest that genotype C is associated with more severe liver diseases than the B variant.

Adolescent↗
PubMed2001

A novel, cell-specific attenuation of a herpes simplex virus type 1 infection in vivo.

We have observed a cell-specific attenuation of herpes simplex virus type 1 strain 17syn+ in vivo that was dependent upon the cell type used to grow the virus. Direct corneal infection of rabbits with 17syn+ propagated in Vero cells caused 60% (6 of 10) to develop severe central nervous system (CNS) disease as evidenced by seizures and/or paralysis; all neurologically impaired rabbits died. In contrast, infection of rabbits with 17syn+ propagated in BHK-21 cells induced seizures and was fatal in 10% (1 of 10). The cell-specific attenuation of a 17syn+ occurred after one growth cycle in BHK-21 cells. To determine whether the decreased virulence of the BHK-21 cell-grown virus correlated with a less severe CNS inflammatory reaction, CNS tissues from rabbits infected with 17syn+ grown in Vero and BHK-21 cells were compared. Histopathological analyses revealed no differences in the location or severity of inflammatory lesions from rabbits infected with virus grown in either cell type. Virus-induced corneal disease was less dependent upon the cell type used to propagate the virus as there were no significant differences in the type or severity of observed corneal lesions. Possible explanations based on differences between Vero and BHK-21 cells are discussed.

Animals↗
PubMed2001

Cost-effectiveness of raloxifene and hormone replacement therapy in postmenopausal women: impact of breast cancer risk.

OBJECTIVE: To examine the life expectancy and cost-effectiveness of hormone replacement therapy (HRT) and raloxifene therapy in healthy 50-year-old postmenopausal women. METHODS: We performed a cost-effectiveness analysis using a Markov model, discounting the value of future costs and benefits to account for their time of occurrence. RESULTS: Both HRT and raloxifene therapy increase life expectancy and are cost-effective relative to no therapy for 50-year-old postmenopausal women. For women at average breast cancer and coronary heart disease risk, lifetime HRT increases quality-adjusted life expectancy more (1.75 versus 1.32 quality-adjusted life years) and costs less ($3802 versus $12,968) than lifetime raloxifene therapy. However, raloxifene is more cost-effective than HRT for women at average coronary risk who have a lifetime breast cancer risk of 15% or higher or who receive 10 years or less of postmenopausal therapy. Raloxifene is also the more cost-effective alternative if HRT reduces coronary heart disease risk by less than 20%. CONCLUSIONS: Assuming the benefit of HRT in coronary heart disease prevention from observational studies, long-term HRT is the most cost-effective alternative for women at average breast cancer and coronary heart disease risk seeking to extend their quality-adjusted life expectancy after menopause. However, raloxifene is the more cost-effective alternative for women at average coronary risk with one or more major breast cancer risk factors (first-degree relative, prior breast biopsy, atypical hyperplasia or BRCA1/2 mutation). These results can help inform decisions about postmenopausal therapy until the results of large scale randomized trials of these therapies become available.

Breast Neoplasms↗
PubMed2001

The management of white phosphorus burns.

Phosphorus burns are a rarely encountered chemical burn, typically occurring in battle, industrial accidents, or from fireworks. Death may result even with minimal burn areas. Early recognition of affected areas and adequate resuscitation is crucial. Amongst our 2765 admissions between 1984 and 1998, 326 patients had chemical burns. Seven admissions were the result of phosphorus burns. Our treatment protocol comprises 1% copper sulfate solution for neutralization and identification of phosphorus particles, copious normal saline irrigation, keeping wounds moist with saline-soaked thick pads even during transportation, prompt debridement of affected areas, porcine skin coverage or skin grafts for acute wound management, as well as intensive monitoring of electrolytes and cardiac function in our burns center. Intravenous calcium gluconate is mandatory for correction of hypocalcemia. Of the seven, one patient died from inhalation injury and the others were scheduled for sequential surgical procedures for functional and cosmetic recovery. Cooling affected areas with tap water or normal saline, prompt removal of phosphorus particles with mechanical debridement, intensive monitoring, and maintenance of electrolyte balance are critical steps in initial management. Fluid resuscitation can be adjusted according to urine output. Early excision and skin autografts summarize our phosphorus burn treatment protocol.

Adolescent↗
PubMed2001

Translational regulation as a novel mechanism for the development of cellular drug resistance.

Cellular drug resistance is one of the principal obstacles to the clinical efficacy of cancer chemotherapy. In this review, we describe the potential role for translational regulation as a novel mechanism for modulating chemosensitivity. The evidence for the translational control of thymidylate synthase, dihydrofolate reductase, and p53 will be presented, as will experimental data showing how disruptions in this important regulatory process can lead to the rapid emergence of cellular drug resistance.

Antineoplastic Agents↗
PubMed2001

Salvage of completely degloved finger with a posterior interosseous free flap.

The use of a free posterior interosseous skin flap should be considered in a single digit degloving injury, especially when replantation of the avulsed skin or the use of skin from the second toe, transferred as a composite-tissue flap, is not feasible. The flap is thin and pliable. It allows early mobilisation with good recovery of joint motion and attains protective sensation of the finger.

Accidents, Occupational↗
PubMed2001

Snapping during manual stretching in congenital muscular torticollis.

Manual stretching frequently is used in the treatment of congenital muscular torticollis in infants. During manipulation, it is not uncommon for the sternocleidomastoid muscle to snap or suddenly give way. The main objective of this study was to evaluate the predisposing causes and clinical significance of such snapping. Four hundred fifty-five patients younger than 1 year of age with congenital muscular torticollis treated with a standardized gentle manual stretching program during a 13-year period were studied. Using prospective standardized assessment parameters, the pretreatment, treatment, and followup results of a group of 41 patients with snapping detected during treatment were compared with the results of a group of 404 patients without snapping during treatment. The group with snapping was associated with a more severe sternomastoid tumor, higher incidence of hip dysplasia, earlier clinical presentation, and shorter duration of treatment. With a mean followup of 3.5 years, the group with snapping was not different from the group that had no snapping in the final assessment score and percentage requiring surgery. From this study, unintentional snapping during the gentle manipulation treatment of congenital muscular torticollis has clinical and ultrasonographic evidence of partial or complete rupture of the sternocleidomastoid muscle. No long-term deleterious effect on the outcome was observed after the snapping.

Female↗
PubMed2001

Reconstruction of burn scar of the upper extremities with artificial skin.

The management of upper-extremity burn contractures is a major challenge for plastic surgeons. After approval by the Food and Drug Administration, artificial skin (Integra) has been available in Taiwan since 1997. From January of 1997 to July of 1999, the authors applied artificial skin to 13 severely burned patients for the reconstruction of their upper extremities, resulting in an increased range of motion in the upper-extremity joints and improved skin quality. An additional benefit was the rapid reepithelialization of the donor sites. There were no complications of infection throughout the therapeutic course, and the overall results were satisfactory. During the 2-year study, scar condition was monitored between 8 and 24 months, and a good appearance and pliable skin were obtained according to the Vancouver Scar Scale. According to this evaluation of Oriental skin turgor, normal pigmentation was restored about 6 months after the resurfacing procedure. For patients with severe burns in whom there is insufficient available skin for a full-thickness skin graft or another appropriate flap for scar revision, Integra is an alternative. The two major concerns in dealing with artificial skin are (1) a 10- to 14-day waiting period for maturation of the neo-dermis, necessitating a two-stage operation, and (2) prevention of infection with antibiotics and meticulous wound care.

Adolescent↗
PubMed2001

Clinical determinants of the outcome of manual stretching in the treatment of congenital muscular torticollis in infants. A prospective study of eight hundred and twenty-one cases.

BACKGROUND: The natural history of congenital muscular torticollis and the outcome of different treatment modalities have been poorly investigated, and the results of treatment have varied considerably. METHODS: The main objective of this prospective study was to evaluate the outcomes of 821 consecutive patients with congenital muscular torticollis who were first seen when they were less than one year old, were treated with a standardized program of manual stretching, and were followed for a mean of 4.5 years. Before treatment, the patients were classified into one of three clinical groups: (1) palpable sternomastoid tumor, (2) muscular torticollis (thickening and tightness of the sternocleidomastoid muscle), and (3) postural torticollis (torticollis but no tightness or tumor). RESULTS: Of the 821 patients, 452 (55%) had a sternomastoid tumor; 276 (34%), muscular torticollis; and ninety-three (11%), postural torticollis. Multivariate analysis of the outcomes showed that (1) the duration of treatment was significantly associated with the clinical group (p < 0.0001), a passive rotation deficit of the neck (p < 0.0001), involvement of the right side (p < 0.0001), difficulties with the birth (p < 0.009), and age at presentation (p < 0.0001); (2) the overall final assessment score was associated with the rotation deficit (p = 0.02), age at presentation (p = 0.014), and duration of treatment (p < 0.0001); and (3) subsequent surgical treatment was required by 8% (thirty-four) of the 452 patients in the sternomastoid tumor group compared with 3% (eight) of the 276 patients in the muscular torticollis group and 0% (none) of the ninety-three patients in the postural torticollis group. CONCLUSIONS: This large prospective study demonstrated that controlled manual stretching is safe and effective in the treatment of congenital muscular torticollis when a patient is seen before the age of one year. The most important factors that predict the outcome of manual stretching are the clinical group, the initial deficit in rotation of the neck, and the age of the patient at presentation. Surgical treatment is indicated when a patient has undergone at least six months of controlled manual stretching and has residual head tilt, deficits of passive rotation and lateral bending of the neck of >15 degrees, a tight muscular band or tumor, and a poor outcome according to our special assessment chart.

Age Factors↗
PubMed2001

Flash echo gray scale imaging with subtraction in assessment of small hepatocellular carcinoma treated with percutaneous ethanol injection: preliminary report.

OBJECTIVE: To assess the therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma by using a flash echo imaging system, a newly developed technique for detecting echoes from microbubble contrast agents more efficiently. METHODS: Six patients with 7 small nodular hepatocellular carcinomas, proved by fine-needle aspiration cytologic or pathologic examination, were included. Percutaneous ethanol injection was performed until there was no intratumoral color signal on conventional color and power Doppler ultrasonography. A bubble contrast agent was then injected, and flash echo imaging in the subtraction mode was performed for assessment of the therapeutic effect. Dynamic computed tomography, magnetic resonance imaging, and hepatic angiography were also used for evaluation of the therapeutic effect. RESULTS: Five tumors had perfusion defects that were equal in size to or larger than the tumors. No tumor stain was shown on hepatic angiography. Two tumors had partial perfusion defects. Viable tumors were confirmed by tumor resection in 1 case and cytologic examination in the other. CONCLUSIONS: Our preliminary results show that flash echo imaging with subtraction has potential value in evaluation of the therapeutic effect of percutaneous ethanol injection on small hepatocellular carcinoma.

Adult↗
PubMed2000

Lymphoma of bone with initial presentation as a calvarial mass.

A 21-year-old man was examined for a right frontal skull mass that had been present for 4 months. Excision biopsy of the mass revealed diffuse large B-cell lymphoma. Subsequent studies showed right preauricular lymphadenopathy but no systemic involvement. The patient was treated with six courses of CHOP (cyclophosphamide, adriamycin, vincristine, and prednisolone) with adjuvant whole brain irradiation and achieved a complete remission.

Adult↗
PubMed2000

Correlation of ultrasonographic imaging of congenital muscular torticollis with clinical assessment in infants.

Congenital muscular torticollis (CMT) is a common problem affecting infants and children. There is a general lack of standard clinical classification or objective assessment methods. Ultrasonographic imaging of the sternomastoid muscle (SCM) has been carried out in a consecutive series of 436 infants less than 1 y old presenting with CMT over a 5-y period. All patients were classified into three clinical groups: postural torticollis, muscular torticollis and sternomastoid tumor. The severity of the torticollis was also expressed into four subgroups according to the degree of deficits in passive rotation of the neck. The ultrasonographic image of the affected SCM included the echogenicity, texture, motility, softness and the transverse and longitudinal extent of the involvement. The disturbance in the quantitative measurement of the transverse diameter of the lower and upper third of the SCM and the ratio of the measurement to the normal side was recorded. The qualitative and quantitative changes in the SCM image were found to correlate significantly with the clinical typing and severity of rotational deficits of the neck. Ultrasonographic imaging has important potential clinical application in helping the diagnosis, prognostication and monitoring of progress of CMT longitudinally.

Female↗
PubMed2000

The clinical presentation and outcome of treatment of congenital muscular torticollis in infants--a study of 1,086 cases.

BACKGROUND/PURPOSE: The main objectives of this study were to define the clinical patterns and characteristics of congenital muscular torticollis (CMT) presented in the first year of life and to study the outcome of different treatment methods. METHODS: This is a prospective study of all CMT patients seen in 1 center over a 12-year period with uniform recording system, assessment methods, and treatment protocol. RESULTS: From a total of 1,086 CMT infants, 3 clinical subgroups of sternomastoid tumor (SMT; 42.7%), muscular torticollis (MT; 30.6%), and postural torticollis (POST; 22.1%) were identified. The SMT group was found to present earlier within the first 3 months and was associated with higher incidence of breech presentation (19.5%), difficult labor (56%), and hip dysplasia (6.81%). Severity of limitation of passive neck rotation range (ROTGp) was found to correlate significantly with the presence of SMT, bigger tumor size, hip dysplasia, degree of head tilt, and craniofacial asymmetry. CONCLUSIONS: A total of 24.5% of the patients with initial deficits of passive rotation of less than 10 degrees showed excellent and good outcome with active home positioning and stimulation program. The remaining cases with rotation deficits of over 10 degrees and treated with manual stretching program showed an overall excellent to good results in 91.1% with 5.1% requiring subsequent surgical treatment. The most important prognostic factors for the necessity of surgical treatment were the clinical subgroup, the ROTGp, and the age at presentation (P < .001).

Age Factors↗
PubMed2000

The boomerang flap in managing injuries of the dorsum of the distal phalanx.

Finding an appropriate soft-tissue grafting material to close a wound located over the dorsum of a finger, especially the distal phalanx, can be a difficult task. The boomerang flap mobilized from the dorsum of the proximal phalanx of an adjacent digit can be useful when applied as an island pedicle skin flap. The vascular supply to the skin flap is derived from the retrograde perfusion of the dorsal digital artery. Mobilization and lengthening of the vascular pedicle are achieved by dividing the distal end of the dorsal metacarpal artery at the bifurcation and incorporating two adjacent dorsal digital arteries into one. The boomerang flap was used in seven individuals with injuries involving the dorsal aspect of the distal phalanx over the past year. Skin defects in all patients were combined with bone,joint, or tendon exposure. The authors found that the flap was reliable and technically simple to design and execute. This one-step procedure preserves the proper palmar digital artery to the fingertip and has proven valuable for the coverage of wide and distal defects because it has the advantages of an extended skin paddle and a lengthened vascular pedicle. When conventional local flaps are inadequate, the boomerang flap should be considered for its reliability and low associated morbidity.

Arteries↗
PubMed2000

PCR assessment of HSV-1 corneal infection in animals treated with rose bengal and lissamine green B.

PURPOSE: In vivo, the ophthalmic dye rose bengal displays profound antiviral effects against herpes simplex virus (HSV)-1, thus limiting its utility in diagnosis of epithelial keratitis when used before viral culture is performed. In contrast, lissamine green B does not possess significant antiviral activity in vivo. To determine whether polymerase chain reaction (PCR) could successfully detect HSV-1 DNA in ocular samples that have been exposed to ophthalmic dyes, animal models were used to observe the presence of infectious HSV-1 and viral DNA in eyes treated with rose bengal or lissamine green B. METHODS: Animals were bilaterally infected with HSV-1 strain H129, and at daily intervals up to 16 days post infection (dpi) rose bengal or lissamine green B was instilled in the left eyes. The right eyes were not treated with dyes. Swabs of the dye-treated and untreated eyes were assayed by PCR for viral infectivity by culture and the presence of DNA specific for a fragment of the HSV-1 DNA polymerase gene. RESULTS: A statistically equivalent number of samples from lissamine green B-treated and untreated eyes were positive by both viral culture and PCR. In contrast, rose bengal significantly decreased the infectious virus present in ocular secretions. A total of 44% and 78% of the rose bengal-treated and untreated eye samples, respectively, were positive by culture from 1 through 16 dpi. PCR was more sensitive than culture for detection of HSV-1 in rose bengal-treated eyes, in that 74% of rose bengal-treated samples were positive by PCR compared with 44% that were positive by culture during the 16-day period studied. It was also noted that both rose bengal and lissamine green B treatments slightly prolonged the period during which viral DNA was detectable in ocular secretions by PCR, possibly because the singlet oxygen produced by these photoreactive dyes compromised ocular cellular, humoral, and nonspecific immune factors allowing viral DNA to persist for slightly longer periods. CONCLUSIONS: PCR can successfully detect HSV-1 DNA in ocular samples that are culture negative and contain rose bengal or lissamine green B. Visualization of ocular epithelial defects with lissamine green B does not interfere with detection of infectious virus or HSV-1 DNA.

Animals↗
PubMed1999

Vascularity index as a novel parameter for the in vivo assessment of angiogenesis in patients with cervical carcinoma.

BACKGROUND: The importance of angiogenesis now is well recognized. Conventionally, tumor angiogenesis is assessed by determination of microvessel density (MVD) in the surgical specimen. This study examines tumor angiogenesis using power Doppler ultrasound and a quantitative image processing system. The authors hope to develop an in vivo and noninvasive method for quantitating tumor angiogenesis. METHODS: Thirty-five patients with FIGO Stage IB-IIA cervical carcinoma exhibiting visible cervical tumors by transvaginal ultrasound were included in this study. All patients underwent radical abdominal hysterectomy and pelvic lymph node dissection. Transvaginal power Doppler ultrasound was performed before surgery to search for blood flow signals from the tumor. The intratumoral vascularity index (VI) and resistance index (RI) were calculated. The VI was defined as the number of colored pixels divided by the number of total pixels in the defined tumor section. Maximal VI and minimal RI of a certain tumor were used for analysis. Clinical and pathologic data also were recorded. The MVD of the excised tumor was assessed immunohistochemically using a monoclonal antibody against CD34. RESULTS: Significantly higher VI values were noted in Stage II tumors compared with Stage 1 tumors (19.01+/-10.90% vs. 9.09+/-6.59%; P = 0.008), tumors invad-ing+/-50% of the cervical stroma compared with tumors invading < 50% of the cervical stroma (13.20+/-8.20% vs. 5.72+/-5.00%; P = 0.003), tumors with lymphovascular emboli compared with tumors without lymphovascular emboli (17.28+/-8.26% vs. 6.98 +/- 5.09%; P = 0.001), and tumors with pelvic lymph node metastases compared with tumors without pelvic lymph node metastases (26.16+/-7.88% vs. 8.00+/-4.95%; P = 0.021). None of the variables mentioned earlier showed a significant difference in terms of the RI values. No correlation was noted between intratumoral RI and VI in respective tumors (P = 0.53). Analysis of VI revealed linear regression with regard to tumor size (P < 0.001, correlation coefficient [r] = 0.586) and depth of stromal invasion (P = 0.002, r = 0.497). In addition, the MVD exhibited a linear relation with VI (P = 0.006, r = 0.454), tumor size (P = 0.005, r = 0.465), and depth of stromal invasion (P = 0.009, r = 0.436) using simple regression analysis. No correlation could be found between MVD and RI. CONCLUSIONS: In cervical carcinoma, intratumoral VI assessment by power Doppler ultrasound and quantitative image processing system showed better correlation with tumor stage, tumor size, and pathologic findings including depth of stromal invasion, lymphovascular emboli, and pelvic lymph node metastases than intratumoral RI. The in vivo indicator of angiogenic activity (VI) is well correlated with the conventional indicator of tumor angiogenic activity (MVD). Thus, VI could be a useful parameter for the in vivo assessment of global tumor angiogenesis.

Adenocarcinoma↗