Biomedical subjects
Publications and source records attributed to C K Chang.
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Many transplant physicians believe that transplant candidates who enroll in clinical trials may have better outcomes than those who do not enroll. We examined a 7-year cohort (1997-2003) of adult primary, non-HLA identical, living donor kidney transplant (LDKT) recipients to determine whether demographic characteristics predisposed to enrollment and whether participation affected posttransplant care intensity and/or allograft function. Overall, 146 of 512 (28.5%) LDKT recipients enrolled in clinical trials. LDKT recipients who were male and those who lived <100 miles from our transplant center were significantly more likely to participate. During the first post-transplant year, study patients (SPs) had more clinic visits (p < 0.0001) and more allograft biopsies (p = 0.024) compared to nonstudy patients (NSPs), but comparable numbers of hospital readmissions and allograft ultrasounds. SPs and NSPs did not differ in 1-year creatinine clearance, delta creatinine or rejection incidence. Overall graft and patient survival were comparable. We conclude that clinical trial participants were disproportionately male, had increased intensity of post-transplant care but comparable outcomes to nonparticipants.
Two types of double-sided nanostructure, one possessing a slit aperture with parallel grooves and the other possessing a circular aperture with concentric grooves, were fabricated to examine the similarities and differences of their diffraction behavior in one-dimensional (1-D) and two-dimensional (2-D) nanostructures. Based on the projection-slice theory, we conjecture that the surface plasmons in these two different nano-scale grooves possess similar modes. A localized surface plasmon (LSP) was used to examine the transmission characteristics induced by the apertures. The transmission characteristics of the slitted nanostructure and the circular nanostructure aperture were then measured. We coupled the transmission spectra measured from these two apertures with a 1-D parallel groove transmission curve simulated by a 1-D rigorous coupled wave analysis. Measured spectra results show reasonable agreement with the simulated data. We propose that the apparent blueshift observed in the peak frequency of a 2-D nanostructure is due to the difference in the shape of the aperture and the spot transmission characteristics of 1-D and 2-D systems as induced by a LSP.
We previously reported that systemic lupus erythematosus (SLE) patients have a higher risk of insulin resistance and abnormal insulin secretion. Recent studies demonstrated that interleukin (IL)-18, a novel pro-inflammatory cytokine, may be involved in triggering the inflammatory processes in SLE and the concentrations of circulating IL-18 in SLE patients were significantly higher than those in healthy subjects. IL-12 has a synergistic effect with IL-18, and both cytokines are inducers of interferon (IFN)-gamma. The objective of this study was to identify the effect of fasting insulin levels on circulating concentrations of IL-18, IL-12 and IFN-gamma in patients with SLE. Plasma levels of proinflammatory Th-1 cytokines were determined by enzyme-linked immunosorbent assay in a total of 70 female SLE patients and 34 age-matched healthy females. Insulin resistance (IR) and secretion were evaluated by homeostasis model assessment (HOMA). All patients were further classified into subgroups based on the quartiles of fasting insulin levels. SLE patients with fasting insulin levels in the top quartile compared with other quartiles had significantly higher plasma levels of IL-18. The presence of insulin auto-antibodies (IAA) in SLE patients had no influence on plasma levels of IL-18. In addition, fasting insulin levels and HOMA IR were positively correlated with IL-18 in all SLE patients, respectively. In conclusion, elevated circulating IL-18 concentrations corresponded with increases in fasting insulin levels and the status of insulin resistance in patients with SLE.
Spin states of the iron(III) complexes of porphyrin, porphycene, hemiporphycene, and corrphycene bearing both 1-methylimidazole and azide as axial ligands were analyzed with infrared (IR) spectroscopy at 20 degrees C. The IR stretching band of coordinating azide split into two peaks around 2047 and 2017 cm(-1) reflecting an equilibrium between the high- (S = 5/2) and low- (S = 1/2) spin states. The high-spin fraction changed over a 0-90% range among the macrocycles, demonstrating that the tetrapyrrole array is essential to control the equilibrium.
On the basis of a fundamental property of nanoparticles, the self-assembling at a liquid-liquid interface to form "colloidosomes", a heterogeneous reaction takes place on the exposed surface of the nanoparticles to produce the heterodimers of two distinct nanospheres, which can be modified by two different functional molecules in a particle-specific manner.
An investigation of the basic factors which govern the microemulsion electrokinetic chromatography (MEEKC) and micellar electrokinetic chromatography (MEKC) separation of Hematoporphyrin D and its base hydrolysis product, hematoporphyrin derivative (HpD), was performed. These model compounds contain a complex mixture of porphyrin monomers, dimers and/or oligomers, and were utilized to gain insights into the MEEKC/micellar electrokinetic chromatography (MEKC) separation of samples containing highly lipophilic substances. For example, the organic modifier/cosurfactant (1-butanol) and/or oil phase (e.g., 1-octanol in comparison to ethyl acetate) were found to have an apparent influence on the separation selectivity of Hematoporphyrin D, the extent of which was dependent on the chemical nature of the surfactant employed (e.g., sodium dodecyl sulfate vs. sodium cholate). An interesting and important finding was that the presence of an organic modifier (methanol or acetonitrile at a concentration of 20% or higher) in the sample matrix as well as in the run buffer was essential for the optimal MEEKC or MEKC separation of a number of porphyrin monomers (including hematoporphyrin IX and its acetates, most likely hydroxyacetate, diacetate, and vinyl acetate, as well as its dehydration products, hydroxyethylvinyldeuteroporphyrin and protoporphyrin) contained in Hematoporphyrin D. On the other hand, the use of these optimized conditions for the MEEKC or MEKC separation of various oligomeric porphyrin species in HpD were unsatisfactory. As HpD is a well-known and effective photosensitizing agent in photodynamic therapy (a new approach for cancer treatment), the improved separation and characterization of various monomeric and oligomeric porphyrin species in HpD and its starting material, such as Hematoporphyrin D, is a challenging and important task.
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1. There is evidence that the induction of inducible nitric oxide synthase (iNOS) and peroxynitrite by ischaemia/reperfusion may lead to renal cell injury. Herein, we investigated whether Sheng mai san (SMS), a Chinese herbal medicine, protects against renal ischaemic injury during heat stroke by reducing iNOS-dependent nitric oxide (NO) and peroxynitrite formation. 2. Urethane-anaesthetized rats were exposed to heat stress (ambient temperature 43 degrees C) to induce heat stroke. Control rats were exposed to 24 degrees C. Mean arterial pressure and renal blood flow after the onset of heat stroke were significantly lower in heat stroke rats than in control rats. However, both colonic temperature and renal damage score were greater in heat stroke rats compared with control rats. Similarly, plasma NO, creatinine and blood urea nitrogen (BUN), as well as the renal immunoreactivity of iNOS and peroxynitrite, were significantly higher in heat stroke rats compared with their normothermic controls. 3. Pretreatment with SMS (1.2 g/day per rat for 7 consecutive days before the initiation of heat stress) significantly attenuated the heat stroke-induced arterial hypotension, hyperthermia, renal ischaemia and damage, the increased renal immunoreactivity of iNOS and peroxynitrite and the increased plasma levels of NO, creatinine and BUN. Pretreatment with SMS resulted in a prolongation of survival time in heat stroke. 4. The results of the present study suggest that SMS protects against renal ischaemic damage by reducing iNOS-dependent NO and peroxynitrite production during heat stroke.
Systemic lupus erythematosus (SLE) is associated with premature atherosclerosis. Increasing arterial stiffness is closely associated with atherosclerotic cardiovascular diseases, and pulse wave velocity (PWV) is considered to be an indicator of arterial stiffness. The objective of this study was to identify the relationship between brachial-ankle pulse wave velocity (baPWV) and cardiovascular risk factors in patients with SLE. Age, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose (FBS), plasma lipid profile, plasma homocysteine, thiobarbituric acid reactive substances (TBARS), baPWV, ankle-brachial index (ABI), and SLE-related factors were determined in a total of 83 SLE patients (12 males and 71 females). All SLE patients were further classified into two subgroups according to baPWV value (baPWV < 1400 cm/s, n=37 versus baPWV > 1400 cm/s, n=46). The mean baPWV value of studied SLE patients was 1520 +/- 381 cm/s. Age, BMI, SBP, DBP, FBS, TBARS and homocysteine levels were significantly higher in SLE patients with baPWV value > 1400cm/s than in SLE patients with baPWV value < 1400cm/s. In addition, baPWV correlated significantly with age, SBP, DBP, FBS and homocysteine. Moreover, stepwise multiple regression analysis showed that age and SBP were independently associated with baPWV. The results of this study indicate a possible link between vascular stiffness measured by baPWV and cardiovascular risk factors in patients with SLE.
The epidemiology pattern of varicella appears to vary among regions with different climates, population densities, and degrees of development. This study investigated the age-specific varicella zoster virus (VZV) seroprevalence in children aged 0 to 12 years in Taiwan and compared these seroprevalences between free and private vaccination areas. Residual sera were collected from 13 hospitals with 1,401 valid samples. Immunoglobulin G antibodies to VZV were measured by enzyme-linked immunosorbent assay. Parents of 656 children answered questions about the varicella incidence and varicella vaccination history of their children. In the 8-12 year-olds, the seroprevance ranged between 88.0-93.8% in northern, central, and eastern, while it was only 76.1% in southern Taiwan. The seroprevalence of children 0-5 years old were significantly different between free and private vaccination areas. Seropositive children who reported no history of varicella or receiving varicella vaccine accounted for 26.1-59.3% of the total positive cases. Our findings suggest the possible effects of climate, geographical conditions, and lifestyle on the seroepidemiology of VZV in Taiwan. The efforts of implementing a varicella vaccination program in Taiwan should focus on reaching high levels of coverage.
Varicella zoster virus is highly contagious and affects people worldwide. In this study, we collected local epidemiological data and evaluated the cost-effectiveness of varicella vaccination program in Taiwan. To examine the economical consequences of universal vaccination, a model of the incidence and the associated costs in a hypothetical cohort was created each year for 30 years. The incidence increased sharply after the infancy and peaked in children aged 5 years. The hospitalization rate among cases was the highest in infants, followed by adults 30 to 44 years old. The benefit-cost analysis showed that one dollar invested in the program would cost extra 46 cents in direct medical expense, but would save extra 45 cents considering the societal expenses. Substantial economical benefits can occur due to the averted unproductive days for parents. Sensitive surveillance of both varicella and zoster is essential in countries that have implemented or are about to implement varicella vaccination.
Previous studies have failed to estimate the size of population at risk and underestimated the incidence of varicella among susceptible population. In this study, we calculated the incidence of varicella and its complications in Taiwan based on a life table method, in which the size of population at risk was taken into account. Population-based data were obtained from the Bureau of National Health Insurance. The age-specific incidences estimated by the uncorrected and corrected methods were compared. The incidence of varicella increased sharply after infancy and peaked at 16.7% in children aged 5 years. A correction which assumes the introduction of varicella vaccine resulted in a higher incidence of 19.5% in children aged 5 years. The lifetime cumulative incidence increased to around 76%. Sensitive surveillance of varicella and correct incidence estimate among susceptible population are essential in countries that have implemented or are about to implement varicella vaccination.
BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is a rare soft tissue sarcoma usually presenting as nodular cutaneous mass on the trunk and proximal extremity. The tumour grows slowly, typically over years. The standard treatment is wide local excision with at least a 3-cm margin. The local regional recurrence is up to 50%, emphasizing the need for wide margins for local control. A small fraction of DFSP may metastasize, but on histological examination such tumours have features of fibrosarcomas rather than DFSP. HYPOTHESIS: This study was done to review our experience of the time interval to recurrence of DFSP. DESIGN: A retrospective review was undertaken to identify patients with DFSP in our university teaching hospital. METHODS: All patients received their primary surgical treatment in our department between February 1968 and June 2001. Treatment consisted of wide local excision with margins of at least 3 cm. The chi-square test and Fisher's exact test were performed to determine the relationship between recurrence and clinicopathological variables. We evaluated the prognostic variables using the Kaplan-Meier method with log-rank comparison. RESULTS: The median follow-up period was 59 months. The 5 and 10-year disease-free survival (DFS) were 86 and 76%, respectively. The overall recurrence rate was 16.7%. The mean time to recurrence was 38+/-12 months (range 1-100 months). In 30% of those patients with recurrences, the local regional recurrence was after 5 years. CONCLUSION: Wide local excision with good margins decreases local regional recurrences in patients with DFSP. Close surveillance is necessary even beyond 5 years because late recurrences occur.
Lymphatic mapping and sentinel lymphadenectomy have become a routine part of the treatment algorithm for primary melanoma. Their role in the management of thick (>4 mm) lesions is evolving. Our purpose was to evaluate the influence of single lymph node (SLN) histology on survival of patients with thick melanomas. A computerized patient database was accessed to obtain records on patients with thick melanomas. Survival curves were constructed with the Kaplan-Meier method, and a Cox regression analysis was used to establish statistical significance. Between 1997 and 2002, 266 SLN biopsy procedures were performed, using both radioisotope and blue dye, in 259 patients with malignant melanoma. Forty-five patients (17%) had thick melanomas. Twenty patients (44%) had at least one positive sentinel lymph node. The mean disease-free survival (DFS) of SLN-positive patients was 44 months compared with 53 months in SLN-negative patients (P = 0.0221). Increasing Breslow thickness was associated with a decrease in DFS, whereas no other histologic parameters such as Clark level, mitotic rate, or ulceration had an influence on DFS. Our data indicate that the status of the SLN node is predictive of disease-free survival in patients with thick melanomas. SLN biopsy is thus justified in patients with thick melanoma.
PURPOSE OF INVESTIGATION: To evaluate women with cytological high-grade squamous intraepithelial lesions (HGSIL) who received standard colposcopic evaluation and direct diagnostic large loop electric excision for the transformation zone (LLETZ) to determine the feasibility of using LLETZ alone (ie, skipping the colposcopic examination). METHODS: From May 1999 to May 2001, 70 women, with the mean age of 49.58 years (range, 20-82 years) and with cervical HGSIL categorized by the Bethesda system were all evaluated by colposcopic evaluation and LLETZ. Cases with a satisfactory colposcopy examination were classified as group A and those with an unsatisfactory colposcopy examination were classified as group B. "Over-treatment" was determined if the women did not need further LLETZ for evaluation or management. "Under-treatment" was determined if treatment might be potentially inadequate or invasive cancer could be ruled out during a satisfactory colposcopic evaluation. RESULTS: Group A consisted of ten women who were evaluated satisfactorily by colposcopy and group B consisted of 30 women who were not evaluated satisfactorily by colposcopy. Overall 8.6% of the patients (6/70) were considered "over-treated". The rate of over-treatment was 10.0% (4/40) in group A compared with 6.7% (2/30) in group B. In contrast, overall 10% of the patients (7/70) were considered "under-treated". The rate of under-treatment was 10% (1/40) in group A compared with 10% (3/30), in group B. The positive predictive values of group A and B were 90.6% and 88.0%, respectively. The negative predictive values were 33.2% and 40%, respectively. CONCLUSION: Direct diagnostic and therapeutic LLETZ for the management of cervical HGSIL may be a better alternative to colposcopy. This method of treatment avoids the possibility of under-treatment and is associated with an acceptable over-treatment rate, especially for postmenopausal women with cytological HGSIL. LLETZ has a good diagnostic accuracy with minimal morbidity and, most importantly, may help reduce patient anxicty, although further studies are needed to directly examine this effect.
Clear cell sarcoma of the tendons and aponeuroses (CCSTA) is an aggressive, rare soft-tissue tumor representing approximately 1 per cent of all soft tissue sarcomas. Although it appears to be histogenetically related to melanoma, its clinical behavior resembles soft tissue sarcoma with a propensity for lymph node metastases. We report our experience at a tertiary referral center. Eight cases of CCSTA evaluated at the University of Illinois at Chicago's Medical Center between 1980 and 2002 were retrospectively reviewed. Patient data analyzed included age, gender, anatomic location, size of tumor, development of local, regional, and distant recurrence, and patient status at last follow-up. Local recurrence did not develop in any patient. Metastases developed in three patients with median time to presentation of metastases of 23 months (range, 8-36 months) from the time of initial diagnosis. Two of these three patients died of their disease with an average interval until death of 22 months from the time of initial diagnosis. The disease-free 2- and 5-year survivals were 68 per cent and 50 per cent, respectively. The overall 2- and 5-year survivals were 86 per cent and 68 per cent, respectively. CCSTA is an aggressive tumor of the soft tissues. These tumors present a high risk for development of distant disease and therefore warrant aggressive surgical management and treatment. Neither aggressive multiagent chemotherapy nor radiotherapy appeared to have an impact on outcome.
The purpose of this study was to review patients with cancer during pregnancy, the effectiveness of the available methods of treatment, and their prognosis. A retrospective chart review was conducted of all women diagnosed with pregnancy-associated cancer between 1974 and 2002 at the University of Illinois at Chicago Medical Center. The demographics, clinical presentation, time and mode of diagnosis, treatment, pregnancy outcome, and maternal survival were noted. The incidence of carcinoma in pregnancy in the series was 0.32/1000 deliveries. The age ranged from 16 to 41 years (mean 30.5 years). No patient underwent a therapeutic abortion, and all patients delivered a healthy infant with no malformations. Metastases developed in three patients with median time of 44 months (range 13-96 months) to presentation of metastases from the time of initial diagnosis. Association of cancer with pregnancy is a rare occurrence. Rates of specific cancers in pregnant and nonpregnant women appear to be equivalent. Pregnant women with cancer are often diagnosed at a later stage compared to their nonpregnant counterparts. Though the cancer may be diagnosed at a more advanced stage, pregnant patients with cancer do not appear to have a more aggressive clinical course.