Biomedical subjects

J H Chang

Publications and source records attributed to J H Chang.

At least 37 records · Page 2Linked to original sources

PubMed2001

The impact of a multidisciplinary breast cancer center on recommendations for patient management: the University of Pennsylvania experience.

BACKGROUND: Advances in the diagnosis and treatment of breast carcinoma have led to a multidisciplinary approach to management for patients with breast carcinoma. To assess the effect of this approach, the authors performed an evaluation for a cohort of patients examined in a multidisciplinary breast cancer center. METHODS: An analysis was performed for the records of 75 consecutive women with 77 breast lesions examined in consultation in a multidisciplinary breast cancer center between January and June 1998. Each patient's case was evaluated by a panel consisting of a medical oncologist, surgical oncologist, radiation oncologist, pathologist, diagnostic radiologist, and, when indicated, plastic surgeon. A comprehensive history and physical examination was performed, and the relevant mammograms, pathology slides, and medical records were reviewed. Treatment recommendations made before this evaluation were compared with the consensus recommendations made by the panel. RESULTS: For the 75 patients, the multidisciplinary panel disagreed with the treatment recommendations from the outside physicians in 32 cases (43%), and agreed in 41 cases (55%). Two patients (3%) had no treatment recommendation before consultation. For the 32 patients with a disagreement, the treatment recommendations were breast-conservation treatment instead of mastectomy (n = 13; 41%) or reexcision (n = 2; 6%); further workup instead of immediate definitive treatment (n = 10; 31%); treatment based on major change in diagnosis on pathology review (n = 3; 9%); addition of postmastectomy radiation treatment (n = 3; 9%); or addition of hormonal therapy (n = 1; 3%). CONCLUSIONS: The multidisciplinary breast cancer evaluation program provided an integrated program in which individual patients were evaluated by a team of physicians and led to a change in treatment recommendation for 43% (32 of 75) of the patients examined. This multidisciplinary program provided important second opinions for many patients with breast carcinoma.

Adult↗

PubMed2001

Seroprevalence and demographic characteristics of HTLV-I among blood donors in Taiwan: 1996-1999.

Screening for the human T-cell lymphotropic virus type I (HTLV-I) and-II in blood donors was implemented in Taiwan beginning in February 1996. The purpose of the present study was to investigate the changes in HTLV-I seroprevalence in all unpaid blood donors in Taiwan during the period from February 1996 to December 1999 and to determine the influence of age and sex on the HTLV-I seropositivity of donors. HTLV-I and HTLV-II screening was performed using combined HTLV-I/II immunoassay. Repeated reactive samples were confirmed by Western blot analysis. Of a total of 3,701,087 donors in all 6 blood centers in Taiwan, 2,311 (0.058%) were seropositive for HTLV-I. The HTLV-I seropositivity was 0.130%, 0.063%, 0.044%, and 0.032% in the years 1996, 1997,1998, and 1999, respectively. There was a linear increase of HTLV-I seropositivity with advancing age. The HTLV-I carrier rate for female donors was twice that for the male donors. Ninty-seven percent of HTLV-I seropositive results came from first-time donors. Our findings suggest that Taiwan is a low-prevalence nonendemic area for HTLV-I infection. The large-scale HTLV-I screening program has decreased HTLV-I seropositivity among blood donors and is useful for preventing HTLV-I transmission via blood transfusion.

Adolescent↗

PubMed2001

Isolation and characterization of a Bacillus thuringiensis ssp. kurstaki strain toxic to Spodoptera exigua and Culex pipiens.

A strain of Bacillus thuringiensis with dual toxicity was isolated from Korean soil samples and named K2. K2 was determined as ssp. kurstaki (H3a3b3c) by serological test and produced bipyramidal-shaped parasporal inclusions. The plasmid and protein profiles of B. thuringiensis K2 were different from those of the reference strain, ssp. kurstaki HD-1. To verify gene type of B. thuringiensis K2, PCR analysis with specific cry gene primers was performed. The result showed that B. thuringiensis K2 had cry1Aa, cry1Ab, cry1C, and cry1D type genes, whereas ssp. kurstaki HD-1 had cry1Aa, cry1Ab, cry1Ac, and cry2 type genes. In addition, B. thuringiensis K2 had high toxicity against Spodoptera exigua and Culex pipiens, whereas B. thuringiensis ssp. kurstaki HD-1 does not have high toxicity against these two insect species.

Animals↗

PubMed2001

Microvascular decompression of the facial nerve for hemifacial spasm in youth.

OBJECTS: The goal of this study was to investigate the differences between clinical findings in youth and in adulthood on microvascular decompression (MVD) of the facial nerve for the treatment of hemifacial spasm (HFS). METHODS: We retrospectively evaluated 855 patients who underwent MVD from January 1985 to July 1999. In our series of 33 young HFS patients, all patients had definite offending vessels. Interestingly, pathologic tortuous vertebral artery as a possible etiology was more rarely observed in young HFS patients (1/33 patients, 3.0%) than in adult patients (61/822 patients, 7.4%) (P < 0.05). We did not observe any atomical variations of the vessels or any arachnoidal thickening around the root entry zone and cerebellopontine cistern in youths. Furthermore, young HFS patients did not necessarily have poorer surgical outcomes than adult HFS patients. CONCLUSIONS: Our results suggest that the cause and progress of HFS are the same in youth as in adulthood, even though the pathogenesis of early onset remains unclear.

Adolescent↗

PubMed2001

Radiologically confirmed de novo glioblastoma multiforme and hippocampal sclerosis associated with the first onset of nonconvulsive simple partial status epilepticus.

The authors report a case of an unusual progression of glioblastoma multiforme in the temporal lobe associated with the first onset of nonconvulsive simple partial status epilepticus (SPSE), a rare form of status epilepticus. The patient underwent a left temporal craniotomy and the tumor was removed. Concurrently, the hippocampus was removed as well. The pathological diagnosis of the tumor and the hippocampus were glioblastoma multiforme and hippocampal sclerosis. The patient's postoperative course was uneventful.

Brain Neoplasms↗

PubMed2001

Knowing the dancer from the dance: R-gene products and their interactions with other proteins from host and pathogen.

Cloning of plant disease resistance genes is now commonplace in model plants. Recent attention has turned to how the proteins that they encode function biochemically to recognize their cognate Avirulence protein and to initiate the disease-resistance response. In addition, attention has turned to how the Avirulence proteins of pathogens might alter susceptible hosts for the benefit of the pathogen, and what plant proteins might be required for that process.

Bacterial Proteins↗

PubMed2001

Endosurgery and the senior pediatric surgeon.

BACKGROUND: Endosurgery is difficult for the senior pediatric surgeon to master because the technique has a steep learning curve, lacks tactile sense, uses elongated instruments, and is ergonomically tiring. METHODS: The senior author, starting at age 53, has performed more than 300 endoscopic procedures at both children and community hospitals. A full year was required to master laparoscopic Nissen fundoplications. Conversion to open procedures from bleeding and enterotomies were committed in the first year of endosurgery. Facility with endosurgery is gained by performing common and frequent procedures as appendectomies. CONCLUSION: The advantages of endosurgery in pain control and shortened hospitalization make the technique deserving of commitment by the senior pediatric surgeon.

Adolescent↗

PubMed2001

Evaluation of minimally invasive approaches to achalasia in children.

BACKGROUND: Achalasia is an uncommon disease in children, but when present can result in severe disabling symptoms often requiring surgical intervention. This report describes the authors' experience with thoracoscopic (TH) and later laparoscopic Heller (LH) myotomy for definitive treatment of this disease. METHODS: Nine patients with achalasia were referred for surgical therapy. Ages ranged from 5 to 17 years and weight from 23 to 78 kg. All had undergone at least one dilatation with recurrence of symptoms. The first 4 were treated by TH and the last five by LH. The 5 LH procedures also included a partial fundoplication. RESULTS: All procedures were completed successfully using minimally invasive techniques. Operating times averaged 95 minutes for TH and 62 minutes for LH. One patient undergoing TH had a small esophageal perforation repaired primarily. The other 3 TH patients were started on clear liquids within 1 day and discharged on day 2. One patient had recurrent symptoms at 6 months and underwent a LH for an incomplete TH. All 5 LH patients were discharged on postoperative day 1. One had an esophageal perforation 4 days after operation requiring laparoscopic repair. Seven of 9 patients are asymptomatic. Studies of pH levels in 2 asymptomatic TH patients show mild gastroesophageal reflux (GER). CONCLUSIONS: Minimally invasive Heller myotomy is a safe and effective procedure in children. TH results in a slightly longer operating time and hospital stay and, without a partial fundoplication, also may be associated with a higher incidence of silent GER. From these results, we prefer LH with a Dor fundoplication for treatment of achalasia in children.

Adolescent↗

PubMed2001

Functional studies of the bacterial avirulence protein AvrPto by mutational analysis.

Pseudomonas syringae pathovars expressing avrPto are avirulent on plants expressing the resistance gene Pto. Over 85 mutants of avrPto were generated with multiple strategies, and several assays were used to characterize AvrPto function. Only a core of 95 amino acids of the 164 residues was sufficient for binding Pto in the yeast two-hybrid system. Only nine of 65 mutant proteins of AvrPto with amino acid substitutions, created in planta and in vitro, did not interact with Pto in the Gal4 yeast two-hybrid system, suggesting that AvrPto can tolerate many nonconservative substitutions and still interact with Pto. These nine and 12 additional substitution mutants of AvrPto were characterized further. The ability to elicit a hypersensitive response and the effect on pathogenesis in planta for these 21 mutants of AvrPto were strongly correlated with recognition by Pto in the yeast two-hybrid system. Analyses of two proteins with substitutions H54P or D52G/L65P indicated that these residues may be required for delivery into the host cell and protein stability in the bacterial cytoplasm, respectively. The mutants that no longer interacted with Pto and had modified activities in planta were predicted to have changes in their secondary structure.

Alleles↗

PubMed2001

Inflammatory pseudotumor-like follicular dendritic cell tumor: a distinctive low-grade malignant intra-abdominal neoplasm with consistent Epstein-Barr virus association.

Follicular dendritic cell (FDC) tumors are uncommon neoplasms that can involve lymph nodes or extranodal sites. They can exhibit a broad spectrum of histologic appearances and behavior, but the intra-abdominal ones usually pursue an aggressive course. The purpose of this study was to characterize a distinctive variant of FDC tumor morphologically mimicking inflammatory pseudotumor through analysis of the clinicopathologic features of 11 cases. The patients included 10 women and one man (age range, 19-61 years; median age, 40 years) who presented with abdominal discomfort or pain. Six patients had systemic symptoms such as marked weight loss, fever, or malaise. All tumors occurred in intra-abdominal sites: liver (n = 7), spleen (n = 3), and peripancreatic region (n = 1). Of the nine patients with follow-up data, six were alive and well, one developed recurrence at 9 years, and two had repeated recurrences over many years. Grossly, the tumors were usually solitary and fleshy, punctuated by areas of hemorrhage and necrosis. Histologically, in a background of abundant lymphocytes and plasma cells were dispersed spindle or ovoid cells with vesicular nuclei and distinct nucleoli. The degree of nuclear atypia was variable, and some nuclei could be grotesque or resemble Reed-Sternberg cells. Focally, spindle cell fascicles could be formed. The atypical cells were immunoreactive for FDC markers such as CD21/CD35, CD23, and CNA.42. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA was positive in all cases, remarkably highlighting the spindle cells and their atypia. EBV-latent membrane protein-1 was expressed commonly, albeit often focally and weakly. Therefore, inflammatory pseudotumor-like FDC tumor represents a distinctive variant of FDC tumor that differs from conventional FDC tumor in the following aspects: marked female predominance; selective localization in intra-abdominal sites, especially the liver and spleen; frequent presence of systemic symptoms; indolent behavior despite an intra-abdominal location; dispersed distribution of tumor cells and prominent lymphoplasmacytic infiltration; and consistent association with EBV.

Abdominal Neoplasms↗

PubMed2001

Corneal neovascularization.

Corneal neovascularization (NV) is a sight-threatening condition usually associated with inflammatory or infectious disorders of the ocular surface. It has been shown in the field of cancer angiogenesis research that a balance exists between angiogenic factors (such as fibroblast growth factor and vascular endothelial growth factor) and anti-angiogenic molecules (such as angiostatin, endostatin, or pigment epithelium derived factor) in the cornea. Several inflammatory, infectious, degenerative, and traumatic disorders are associated with corneal NV, in which the balance is tilted towards angiogenesis. The pathogenesis of corneal NV may be influenced by matrix metalloproteinases and other proteolytic enzymes. New medical and surgical treatments, including angiostatic steroids, nonsteroidal inflammatory agents, argon laser photocoagulation, and photodynamic therapy have been effective in animal models to inhibit corneal NV and transiently restore corneal "angiogenic privilege."

Angiostatins↗

PubMed2001

Importance of the host genetic background on immune responses to Helicobacter pylori infection and therapeutic vaccine efficacy.

In order to investigate the role of host factors in Helicobacter pylori infection and immunity, two different strains of inbred mice, C57BL/6 and BALB/c, were infected with a standard H. pylori strain, SS1. A month later, infected mice were immunized orally with whole-cell lysates of H. pylori SS1 and cholera toxin on days 1, 3, 6, 30, and 54. Ten days after the last immunization, mice were sacrificed and the stomach was collected to assess H. pylori colonization density by quantitative culture. H. pylori SS1 colonization was significantly greater in C57BL/6 than in BALB/c (P<0.02 and P<0.003 at 2 and 13 weeks post-inoculation, respectively). Colonization in C57BL/6 persisted at equivalent levels for 13 weeks but the colonization density in BALB/c decreased significantly during this period. In contrast to the pattern of bacterial colonization, antibody responses following H. pylori SS1 infection were greater in BALB/c than in C57BL/6, suggesting that host factors may modulate the immune responses to H. pylori infection. Following therapeutic immunization, H. pylori colonization in BALB/c mice was also significantly reduced (P<0.03), while no significant differences in bacterial density were observed in C57BL/6. These observations collectively demonstrate the great importance of host factors in H. pylori infection and the development of effective immune responses.

Adjuvants, Immunologic↗

PubMed2001

Microvascular decompression for hemifacial spasm: a long-term follow-up of 1,169 consecutive cases.

We analyzed the records of 1,169 patients with hemifacial spasm (HFS) who underwent microvascular decompression (MVD) and were followed up for more than 6 months from January 1987. The mean follow-up duration was 23.8 months (6-145 months). Excellent surgical outcome was obtained in 90.5% and good in 4.5%, giving an overall success rate of 95.0%. There was statistically significant relationship between vertebral artery (VA) shift and side of symptom. Permanent facial weakness and hearing impairment were 1.4% and 2.3%, respectively. There were no anatomical differences at the root entry zone (REZ) and significant differences of surgical outcome in young HFS (34 patients). Factors such as type of offender, severity of compression on the facial nerve root, and the degree of decompression of the REZ on postoperative MRI did not correlate with surgical outcome.

Adult↗

PubMed2001

Sensitivity of CD95-induced apoptosis in different proliferative status of human retinal pigment epithelial cells.

It is known that CD95 (APO-1/Fas) is expressed on the cell surface, and apoptotic cell death can be induced by the CD95 ligation in the cultured, proliferating human retinal pigment epithelial (RPE) cells. However, little is known about CD95 on the non-proliferating RPE cells. In this study, human RPE cells were cultured up to 4 weeks after they reached the confluence, to simulate the non-proliferating RPE cells in situ. There was no significant difference in CD95 expression on the cell surface between the predominantly proliferating, preconfluent cells and predominantly non-proliferating, postconfluent cells in flow cytometric assays. However, unlike proliferating cells, no cellular death occurred in the predominantly non-proliferating cells after the treatment of agonistic anti-CD95 antibody with cycloheximide, pretreated with interferon-gamma. Our results suggest that the CD95/CD95L system probably plays a physiologic role in vivo to remove the abnormal, proliferating RPE cells, and factors other than the surface expression of CD95 may determine the sensitivity to the CD95 signals.

Apoptosis↗

PubMed2001

Drug-resistant tuberculosis in a tertiary referral teaching hospital of Korea.

BACKGROUND: Resistance of Mycobacterium tuberculosis strains is an increasing problem worldwide. Our purpose was to determine the prevalence of drug resistance (DR) and risk factors of DR in patients with tuberculosis and to assess the clinical characteristics and socioeconomic status of patients with drug-resistant tuberculosis. METHODS: We retrospectively studied drug susceptibility tests and clinical and socioeconomic records for 308 cases of culture-positive Mycobacterium tuberculosis infection, diagnosed at Mokdong Hospital, Ewha Womans University from March, 1995 to February, 2000. RESULTS: DR to at least one drug was identified in 75 (24.4%); the rate of primary DR, 18.7% and acquired DR, 39.3%. Multi-drug resistance (MDR) was identified in 31 (10.1%); primary MDR, 7.0% and acquired MDR, 21.4%. The risk factors of DR were previous TB treatment, pulmonary involvement and associated medical illness. DR group showed lesser adherence to treatment than the drug-sensitive group. DR group showed more frequent self-interruption of medication, lower completion rate of treatment and higher failure rate of follow-up than the drug-sensitive group. In previously treated tuberculosis patients, higher rate of overall DR and MDR, larger number of resistant drugs and more frequent self-interruption of medication were observed than newly diagnosed patients. Among DR group, acquired DR (ADR) group was older, less educated and treated for longer duration and had more advanced disease than primary DR group. CONCLUSION: Previously treated tuberculosis is a most important risk factor for DR. DR group, especially ADR, showed less compliance with treatment. More proper education and attention to prevent self-interruption should be given to a previously treated group. In TB prevalent areas, it should be considered to obtain initial drug susceptibility testing in high risk of DR.

Adolescent↗

PubMed2001

Multiple high-grade bronchial dysplasia and squamous cell carcinoma: concordant and discordant mutations.

Loss of heterozygosity (LOH) involving chromosomes 3p, 5q, 9p, or 17p and aberrant expression or mutation of p53 are reported previously in selected bronchial dysplasias and squamous cell cancers (SCCs). Yet, comprehensive analyses of LOH patterns at these chromosomal sites and of p53 alterations are not reported for histologically normal bronchial epithelium, high-grade bronchial dysplasia, and SCC present in the same pulmonary resections. Whether concordant or discordant genetic changes are detected in these bronchial tissues, especially when multiple high-grade dysplastic bronchial lesions are present, was studied. Genomic DNA was microdissected from eight pulmonary SCCs and high-grade dysplastic lesions that were associated with SCC. In four cases, two independent high-grade dysplastic bronchial lesions were identified. When available, histologically normal bronchial epithelium was microdissected. Germ-line genomic DNA was isolated from normal lymph nodes. LOH was assessed for 15 microsatellite markers on chromosomes 3p, 5q, 9p, or 17p, sites frequently deleted in lung cancers. Immunohistochemical p53 expression was studied and correlated with p53 DNA sequence analyses. Progressive LOH for these markers was found when SCCs were compared with high-grade dysplasia and histologically normal bronchial epithelium present in the same resections. Histologically normal bronchial specimens had LOH in up to 27% of informative markers. High-grade dysplastic lesions exhibited LOH for 18-45% and SCC had LOH for 18-73% of the markers. Common regions of LOH were found in some dysplasias compared with SCCs. In other dysplasias, discordance was found relative to SCCs, especially for p53 mutations. In cases with a single or second high-grade dysplasia associated with SCC, heterogeneity in LOH markers was detected. These concordant and discordant changes were consistent with convergent and divergent clonal selection pathways in pulmonary squamous cell carcinogenesis. Some histologically normal bronchial epithelial tissues had genetic changes more similar to those in the SCCs than in dysplastic lesions. DNA loss or mutations accumulate in SCC, but discordant genetic changes can exist in the same carcinogen-exposed bronchial tissues. These findings have implications for lung cancer prevention trials.

Bronchial Diseases↗

PubMed2001

Stress fracture of the femoral neck in young adult: report of four cases.

Stress fracture of the femoral neck is an uncommon injury. If the diagnosis is missed or delayed and fracture displacement results, serious complications such as avascular necrosis of the femoral head, nonunion or varus deformity may occur. Treatment depends on the type of stress fracture. Compression and tension stress fractures can be successfully treated with conservative management or prophylactic internal fixation using multiple screws. Displaced stress fractures are an orthopedic emergency, requiring prompt surgical intervention. Poor outcomes after fracture displacement have been reported by many authors. We present four cases demonstrating three types of stress fracture of the femoral neck. It is hoped that these case reports will serve to increase practitioner awareness of this injury and emphasize the need for careful diagnosis and treatment of this potentially problematic injury.

Adult↗

PubMed2001

[Production of transgenic lamb integrated with modified human anti-trypsin gene].

This experiment is to produce the human mAAT(modified anti-trypsin) which cures the emphysema specifically through mammalian galactophore of transgenic goat. 56 goats were selected as donor for superovulation by FSF + LH microinjection in this experiment. The pronucleic embryos were injected with human mAAT gene after fertilization in vivo, and transferred to the donors or receptors directly. The superovulation was better in March and May than in December with the number of ovulation of 19.50, 21.70 and 16.06, and number of fertilized embryos of 4.31, 6.48 and 3.57 per-animal respectively. The pregnant rates were 18.18% and 25% respectively after transferred to donors and receptors with natural estrus. The donors also can be used as the embryo receptor with no remarkable decrease of pregnant rate. 29 lamb were labored. 4 positive transgenic lamb were checked by PCR, PCR-Southern and Southern analysis. The integrated efficiency of foreign DNA was 13.79% with microinjection of high copy number of foreign DNA fragment.

Animals↗