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Biomedical subjects

B W Chang

Publications and source records attributed to B W Chang.

At least 19 recordsLinked to original sources

Wet and dry deposition patterns of plutonium in Daejeon, Korea.

Plutonium in wet and dry deposition samples collected monthly at the Korea Institute of Nuclear Safety (KINS), Daejeon, Korea was determined during the period from January 2000 to August 2000. Monthly 239,240Pu deposition in Korea showed a maximum in the spring season (March to May), which was several times greater than that in Japan and corresponds to a seasonal cycle of soil dust fallout originating from the East Asian arid areas. The trajectory analysis of dust storms suggests that 239,240Pu deposition in Korea in spring is originating from plutonium-bearing surface soil particles from the East Asian arid areas. A significant part of the 239,240Pu deposition in spring in Korea is attributable to dry deposition.

Air Movements↗

Recent trends of plutonium fallout observed in Japan: plutonium as a proxy for desertification.

Plutonium in monthly deposition samples collected in Tsukuba (the Meteorological Research Institute), Japan from 1990 to end of 2001 is reported, together with monthly plutonium deposition in Nagasaki and Yonaguni in 2000. The annual deposition of (239,240)Pu during the period from 1990 to 2001 shows no systematic interannual variation. However, monthly (239,240)Pu depositions show a typical seasonal variation with a maximum in spring season (March to April), which corresponds to seasonal cycle of soil dusts originating from the East Asian arid area. Plutonium isotopic ratios in the deposition samples suggest that significant amounts of the recent (239,240)Pu deposition observed in Japan are attributed to the resuspension of plutonium-bearing surface soil particles; resuspended plutonium originates from the East Asian arid areas. The recent increased tendency of (239,240)Pu content in residues in deposition samples may reflect desertification in the East Asian continent.

Asia↗

Assays for angiotensin converting enzyme inhibitory activity.

A colorimetric method and a capillary electrophoresis procedure were developed for quantifying histidyl-leucine and hippurate, respectively. The colorimetric method is sensitive (extinction coefficient = 7.5 mM(-1) cm(-1)) and reproducible (CV = 1.7%, n = 5), which is based on a selective chromogenic reaction for histidyl-leucine (lambda(max) = 390 nm) using o-phthalaldehyde. For samples containing unusually high levels of histidine and/or histidyl peptides, the separation-based approach is preferable. The capillary electrophoresis method makes use of an in-capillary microextraction technique; complicated samples can be measured in less than 4 min without pretreatment. Protocols using both methods to measure angiotensin converting enzyme inhibitory activity were proposed.

Angiotensin-Converting Enzyme Inhibitors↗

Surgeon perspectives on surgical options for early-stage breast cancer.

To evaluate the practice patterns of general and plastic surgeons regarding patients with early-stage breast cancer, all general and plastic surgeons in Quebec and Maryland were mailed self-administered questionnaires evaluating surgeon demographics, practice patterns, treatment preferences, and satisfaction with the results of lumpectomy and radiation therapy or breast reconstruction. Response rates of 38.3 percent and 26.7 percent were obtained for general surgeons in Quebec and Maryland, respectively. The ratio of reported mastectomies to lumpectomies was 1:2 in Maryland and 1:5 in Quebec. All general surgeons considered lumpectomy an important option. Ninety percent of Maryland surgeons versus 44 percent of Quebec surgeons considered mastectomy important. A total of 53.6 percent versus 24.9 percent of general surgeons in Maryland and Quebec, respectively, considered delayed reconstruction an important option. Additionally, 81.3 percent of Maryland surgeons considered immediate reconstruction important, and 79.6 percent discussed it with all stage I or II patients. More than 75 percent of Quebec general surgeons reported discussing immediate or delayed reconstruction with < or =50 percent of these women. Response rates of 53.6 percent and 48.8 percent were obtained for plastic surgeons in Quebec and Maryland, respectively. In one year Quebec plastic surgeons reported that they performed less than half the number of reconstructions performed by Maryland plastic surgeons (7.2 versus 17.3). In Quebec, 82.3 percent of surgeons reported that they frequently discuss delayed reconstruction, 25.1 percent immediate, 62.5 percent pedicled TRAM, and 51.7 percent nonautogenous options. In Maryland, 74.3 percent of plastic surgeons frequently discuss delayed reconstruction, 95.7 percent immediate, 89.9 percent pedicled TRAM, and 85.9 percent nonautogenous options. For women with early-stage breast cancer, regional variations exist in the surgical options discussed and provided.

Attitude of Health Personnel↗

Adult onset grape hypersensitivity causing life threatening anaphylaxis.

BACKGROUND: Adverse reactions to foods are encountered much less frequently in adults than in the children. Adult onset hypersensitivity to grapes has not been previously reported. OBJECTIVE: Evaluation of a case of anaphylaxis that occurred as a result of the consumption of white grapes (Vitis vinifera). METHODS AND RESULTS: A 28-year-old woman experienced generalized urticaria, facial/oropharyngeal angioedema, and dizziness after eating a bunch of white grapes. She was treated in an emergency room for anaphylaxis. Previously, she had experienced two similar episodes after eating white grapes. The grape prick skin tests were strongly positive forming a pseudopod type reaction. The total serum IgE was 1918 ng/mL. The grape-specific serum IgE was weakly positive by the modified RAST and negative in the Pharmacia-Upjohn Cap System. CONCLUSION: Hypersensitivity to a commonly consumed fruit such as grapes can develop late in life causing a near-fatal anaphylaxis.

Adult↗

Surgical options for the early-stage breast cancer: factors associated with patient choice and postoperative quality of life.

Patients with early-stage breast cancer have three surgical options: lumpectomy with radiotherapy, mastectomy alone, and mastectomy with breast reconstruction. Our objective was to compare women in these three groups with respect to demographics, preoperative counseling, postoperative body image, and quality of life. Women having undergone surgery for stage 1 or 2 breast cancer between 1990 and 1995 were selected by random sampling of hospital tumor registries and were mailed a self-administered questionnaire, which included the Medical Outcomes Survey Short Form 36. Patients were stratified into three mutually exclusive groups: lumpectomy with axillary node dissection and radiotherapy, modified radical mastectomy, and modified radical mastectomy with breast reconstruction. In total, 267 of 525 surveys were returned (50.9 percent). Compared with mastectomy patients, breast reconstruction patients were younger (p < 0.001), better educated (p = 0.001), and more likely Caucasian (p = 0.02). Among mastectomy patients, 54.9 percent recalled that lumpectomy had been discussed preoperatively and 39.7 percent recalled discussion of breast reconstruction. Post-operative comfort with appearance was significantly lower for mastectomy patients. The relationship between type of surgery and postoperative quality of life varied with age. Under 55, quality of life was lowest for mastectomy patients on all but two Medical Outcomes Survey Short Form 36 subscales. Over 55, quality of life was lowest for lumpectomy patients on all subscales (p < 0.05 for all subscales except social functioning and role-emotional). Treatment choice may be related to age, race, education, and preoperative counseling. Whereas the effect of breast cancer on a woman's life is complex and individual, the type of surgery performed is a significant variable, whose impact may be related to patient age.

Adult↗

Imaging spectrum of extracapsular silicone: correlation of US, MR imaging, mammographic, and histopathologic findings.

The appearance of free silicone at mammography, ultrasonography (US), and magnetic resonance (MR) imaging is variable. The classic appearance is dense areas of opacity on mammograms, a highly echogenic pattern with or without hypoechoic masses on US images, and foci of low signal intensity on fat-suppressed T1-weighted MR images or high signal intensity on water-suppressed T2-weighted MR images. Mammography is a reliable, cost-effective, and readily available means of demonstrating silicone. The major disadvantage of US is that its accuracy depends on the capability of the operator to recognize the abnormality. Although MR imaging outperforms US or mammography in detection of implant rupture, it is not clear that MR imaging is superior in detection of free or residual silicone. The sequelae of noncontained silicone include granuloma formation, fibrosis, and migration. After extrusion from an implant, silicone migrates primarily to local sites, such as the ipsilateral chest wall and axillary nodes. Migration of silicone into the axilla can involve the brachial plexus, resulting in neuropathy. Silicone can also migrate into more distal regions, including the arm and subcutaneous tissues of the abdominal wall. Whatever the source, silicone in breast tissue interferes with the interpretation of mammographic findings.

Adult↗

Late capsular hematoma after breast reconstruction with polyurethane-covered implants.

We report two patients who developed late hematomas after breast reconstruction with polyurethane-covered implants. Although the cause of these hematomas is not absolutely clear, they are believed to have been caused by the intense, highly vascular inflammatory response that polyurethane coating is known to elicit. The development of late hematoma has not been previously stressed in the literature as a late complication of polyurethane-covered breast implants.

Adult↗

Shaping the autologous breast.

Autologous breast reconstruction has become increasingly popular in the past several years as more experience has been gained in the various techniques. Advantages to autologous reconstruction include improved shaping and symmetry, which also allow for a more natural reconstruction. The transverse rectus abdominis myocutaneous (TRAM) flap (free and pedicled) and latissimus flap are the predominant methods used although many newer donor sites have also been described. This article discusses techniques that allow the reconstructive surgeon to plan and execute the reconstruction of a natural breast reconstruction with autologous tissue.

Female↗

Single- and double- lumen silicone breast implant integrity: prospective evaluation of MR and US criteria.

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) and ultrasound (US) criteria for breast implant integrity. MATERIALS AND METHODS: One hundred twenty-two single-lumen silicone breast implants and 22 bilumen implants were evaluated with surface coil MR imaging and US and surgically removed. MR criteria for implant failure were a collapsed implant shell ("linguine sign"), foci of silicone outside the shell ("noose sign"), and extracapsular gel, US criteria were collapsed shell, low-level echoes within the gel, and "snowstorm" echoes of extracapsular silicone. RESULTS: Among single-lumen implants, MR imaging depicted 39 of 40 ruptures, 14 of 28 with minimal leakage; 49 of 54 intact implants were correctly interpreted. US depicted 26 of 40 ruptured implants, four of 28 with minimal leakage, and 30 of 54 intact implants. Among bilumen implants, MR imaging depicted four of five implants with rupture of both lumina and nine of 10 as intact; US depicted one rupture and helped identify two of 10 as intact. Mammography accurately depicted the status of 29 of 30 bilumen implants with MR imaging correlation. CONCLUSION: MR imaging depicts implant integrity more accurately than US; neither method reliably depicts minimal leakage with shell collapse. Mammography is useful in screening bilumen implant integrity.

Breast Implants↗

Breast implant rupture: diagnosis with US.

PURPOSE: To characterize sonographic criteria for the detection of implant rupture. MATERIALS AND METHODS: One hundred nineteen symptomatic women (221 silicone implants) were evaluated with ultrasound (US) over 11 months to detect implant rupture. Fifty-nine breast prostheses in 31 women were surgically removed. RESULTS: Five sonographic findings associated with rupture were identified: echogenic noise, low-level homogeneous echoes within the implant, echogenic lines coursing within the implant, a contour bulge of the implant, and peri-implant fluid accumulations. The most useful finding in the detection of implant rupture was low-level homogeneous echoes, which were associated with 55% of ruptured implants and 16% of intact implants. This was statistically significant, achieving a 55% sensitivity and 84% specificity for the detection of implant rupture. Nine of 22 ruptured implants (41%) displayed none of the described criteria. CONCLUSION: US may be useful to detect implant rupture; however, a larger prospective study is necessary for adequate evaluation.

Equipment Failure↗

Color Doppler flow mapping of abdominal wall perforating arteries for transverse rectus abdominis myocutaneous flap in breast reconstruction: method and preliminary results.

PURPOSE: To describe the use of color Doppler flow ultrasound (US) in preoperative mapping of small perforating arteries in the abdominal wall that supply the transverse rectus abdominis myocutaneous (TRAM) flap used primarily for breast reconstruction. MATERIALS AND METHODS: With a grid (clear x-ray film) and a high-frequency linear-array transducer, the size and position of perforating arteries as they exit the rectus abdominis muscle were mapped preoperatively in 35 patients. Twenty-three of these patients had previously undergone abdominal surgery; 26 underwent reconstruction and clinical follow-up. RESULTS: Operating time was decreased and flap design was planned to include the largest perforating arteries and minimize the overall abdominal wall defect. Two of the 26 patients who underwent TRAM flap reconstruction had partial flap loss: One continued to smoke, which may have caused microvascular compromise; and a paucity of perforating arteries was seen in the second patient. CONCLUSION: Preoperative mapping of perforating arteries for TRAM flap reconstruction provides a rational basis for flap design and patient selection, which may affect flap survival.

Abdominal Muscles↗

MR imaging of the breast in patients with silicone breast implants: normal postoperative variants and diagnostic pitfalls.

Because of the wide variety of types of silicone breast implants, modifications, and surgical procedures, a number of normal variants and potentially misleading appearances can be encountered on MR images of breast implants. Familiarity with these findings is essential to proper interpretation of these images. The purpose of this essay is to illustrate the overlap in appearances of MR images in different clinical scenarios. When confusing findings are present, confirmation of the surgical history can usually clarify the matter.

Adult↗

Diagnosing breast implant rupture with MR imaging, US, and mammography.

A total of 135 symptomatic women with 262 breast implants were examined with magnetic resonance (MR) imaging performed with a body coil, ultrasound (US), or both to determine imaging features of implant rupture. Surgical proof was available for 33 women with 62 implants; 24 were ruptured and 38 were intact. Complicated internal structure was the most reliable predictor of implant rupture: Diffuse low-level echoes were seen on sonograms in 56% of ruptured implants; internal membranes (which correspond to the collapsed implant shell) were seen on MR images in 58% of ruptured implants. Fluid droplets were seen within the silicone in 26% of ruptured implants on MR images. Irregular implant contour can be a sign of rupture but is unreliable. Fluid collections around silicone implants are not a sign of rupture. At present, neither US nor conventional MR imaging with a body coil is sufficiently reliable to advocate routine screening of asymptomatic women with breast implants. Evaluation with MR imaging performed with a surface coil is more reliable.

Breast↗

A systematic approach to repair of syndactylism.

An approach to the repair of syndactyly is presented whereby the web space is dissected in anatomically defined planes. This technique is preferred because it allows a reliable means of removing interdigital fibrofatty tissue while preserving the neurovascular bundles. Digital contour is improved and wound healing is promoted by less skin tension due to removal of the fibrofatty tissue.

Adipose Tissue↗