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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 397 records · Page 22Linked to original sources
PubMed1992

The activation of major histocompatibility complex class I genes by interferon regulatory factor-1 (IRF-1).

We have investigated the role of interferon regulatory factor-1 (IRF-1), an interferon-gamma (IFN-gamma) inducible transcriptional activator, on major histocompatibility complex (MHC) class I gene transcription. IRF-1 alone is sufficient to trans-activate both transfected and endogenous class I genes and the effect of IRF-1 appears to be direct and sequence-specific. These data suggest that IRF-1 is involved in the IFN-gamma mediated induction of MHC class I expression.

Base Sequence↗
PubMed1992

Renal cortical and renal medullary necrosis in the first 3 months of life.

Renal cortical necrosis, renal medullary necrosis, and combined renal cortical-medullary necrosis result from renal ischemia without vascular occlusion. Renal hypoperfusion and ischemic injury in infants have been ascribed to massive blood loss, hemolytic disease, septicemia, and severe hypoxemia. In a postmortem study we identified 82 cases among 1,638 autopsies during the 20 years between 1970 and 1989 in infants 3 months old or less at the time of death. The frequency of renal necrosis in autopsy cases increased significantly during the last 6 years of the study. The distribution of the renal lesion was cortical in 28, medullary in 23, and combined in 31. Forty infants carried diagnoses of congenital heart disease, 17 of asphyxial shock, 9 of sepsis, 3 of infectious myocarditis, 9 of major malformations, 4 of anemic shock, 1 of vascular malformation, and 1 of gastroenteritis and dehydration. A significantly higher proportion of babies with congenital heart disease had cortical involvement. Comparison of clinical characteristics revealed a significantly higher frequency of prematurity, respiratory distress syndrome, bleeding diathesis, and possibly sepsis in the children with congenital heart disease, suggesting that these factors are important in the pathogenesis of the renal lesion. Fourteen infants underwent cardiac catheterization; there was no demonstrable association between the renal lesions and the use of radiographic contrast medium. We conclude that severe congenital heart disease itself is a risk factor for life-threatening renal cortical and medullary necrosis.

Female↗
PubMed1992

One-stage operation for treatment after delayed diagnosis of thoracic esophageal perforation.

Perforation of the thoracic esophagus can be fatal unless diagnosed promptly and treated effectively. The high mortality with delayed treatment is due principally to an inability to effectively close the perforation and prevent leakage. From 1982 to 1988, 7 consecutive patients (aged 16 to 73 years) were treated after a delayed diagnosis (26 hours to 25 days) of thoracic esophageal perforation. In all patients, the perforation was closed after debridement with total exclusion of the esophagus (T-tube cervical esophagostomy plus absorbable ligatures applied to the esophagogastric junction and the cervical esophagus distal to the esophagostomy). Radical decortication and wide mediastinal and pleural drainage were also done. Nutritional supply was given through a feeding gastrostomy. Antibiotics were administered according to the results of cultures. All patients survived. Continuity of the esophagus was established by removal of the T tube and spontaneous absorption of the ligatures. Endoscopy and esophagography performed 4 weeks after the initial operation showed a well-healed esophagus without stenosis or leakage in all patients. No secondary thoracotomy or esophageal reconstruction was necessary. No dysphagia was noted during follow-up (range, 12 to 50 months; mean follow-up, 23 months). We conclude that primary closure of the perforation and total esophageal exclusion with the use of absorbable ligatures and T-tube esophagostomy can provide a one-stage operation with good results for repair of thoracic esophageal perforation diagnosed late.

Adolescent↗
PubMed1992

Microheterogeneity of a purified IgG1 due to asymmetric Fab glycosylation.

A murine monoclonal anti-granulocyte IgG1, IMMU-MN3, was seen to exhibit heterogeneity. On reduced SDS-PAGE, the purified antibody appeared as two heavy-chain bands of unequal intensity, and only one light-chain band. Hydrophobic interaction chromatography (HIC) also resolved two populations of the IMMU-MN3 antibody. Based on Concanavalin A affinity chromatography, enzymatic digestion with Endoglycosidase F and carbohydrate analysis, it was found that the heterogeneity detected by SDS-PAGE and HIC was due to differences in glycosylation. Furthermore, sequential gel analysis (non-reduced/reduced) demonstrated that the upper heavy-chain band was asymmetrically glycosylated.

Animals↗
PubMed1992

Primary structure of an inactive mutant of phospholipase A2 in the venom of Bungarus fasciatus (banded krait).

From the acidic components of Bungarus fasciatus venom, a very small amount (0.16%) of a novel phospholipase A2 was obtained. Both neurotoxicity and enzyme activity were found to be lacking. Amino acid sequence study showed that it has a normal backbone of group I snake venom phospholipase A2 with 118 amino acid residues. The lack of enzyme activity was attributed to its mutation of the indispensable Asp residue to an Ala residue, i.e., the usual His-Asp47 turned out to be His-Ala47. This is the eighth isoform of phospholipase A2 found from the venom of Bungarus fasciatus. Examination of structural homology with three other isoforms revealed 66% similarity at most.

Amino Acid Sequence↗
PubMed1992

The functions of tryptophan residues in membrane proteins.

Membrane proteins have a significantly higher Trp content than do soluble proteins. This is especially true for the M and L subunits of the photosynthetic reaction center from purple bacteria. The Trp residues are not uniformly distributed through the membrane but are concentrated at the periplasmic side of the complex. In addition, Trp residues are not randomly aligned. Within the protein subunits, many form hydrogen bonds with carbonyl oxygens of the main chain, thereby stabilizing the protein. On the surface of the molecule, they are correctly positioned to form hydrogen bonds with the lipid head groups while their hydrophobic rings are immersed in the lipid part of the bilayer. These observations suggest that Trp residues are involved in the translocation of protein through the membrane and that following translocation, Trp residues serve as anchors on the periplasmic side of the membrane.

Hydrogen Bonding↗
PubMed1992

Studying outcomes and hospital utilization in the elderly. The advantages of a merged data base for Medicare and Veterans Affairs hospitals.

That veterans aged 65 years and older are eligible to receive care either in the Veteran Affairs (VA) health care system or in the private sector under Medicare confounds the analysis of veterans' health services utilization and outcomes in two ways. First, changes in eligibility or financial barriers to access with regard to either system influence veterans' decisions about where to seek needed care. Second, analyses of VA care for elderly veterans that rely solely on VA data sources underestimate both overall utilization and treatment complications. Similarly, failure to consider the contribution of health care delivery in the VA system may confound analyses of health care utilization by the Medicare-eligible population. To study the magnitude of such confounding influences, we linked the Medicare and VA health care administrative databases for residents of New England and New York. Results indicated that, for ten surgical procedures commonly performed in the elderly, as well as for hospitalizations resulting from acute myocardial infarction and hip fracture, VA patients receive from 17.6% to 37.4% of hospital care outside the VA system. Private hospitalizations account for 5.5% to 19.5% of the care received by veterans within 6 months after an initial episode of care in a VA hospital. It was also found that initial hospitalizations for study conditions in the VA accounted for 3.6% of all such hospitalizations among elderly Medicare-eligible men. Although overall hospital utilization appears to be underestimated in VA data sources, it was found that ascertaining mortality from sources available within the VA produced excellent results when compared with deaths recorded in the Medicare enrollment files. A national, merged VA-Medicare data base is feasible and would enhance the validity of analyses of health care delivery both for elderly veterans and for the Medicare population.

Aged↗
PubMed1992

Functional roles assigned to the periplasmic, linker, and receiver domains of the Agrobacterium tumefaciens VirA protein.

VirA and VirG activate the Agrobacterium tumefaciens vir regulon in response to phenolic compounds, monosaccharides, and acidity released from plant wound sites. VirA contains an amino-terminal periplasmic domain and three cytoplasmic domains: a linker, a protein kinase, and a phosphoryl receiver. We constructed internal deletions of virA that truncate one or more domains and tested the ability of the resulting proteins to mediate environmentally responsive vir gene activation in vivo. The periplasmic domain is required for sensing of monosaccharides (in agreement with earlier results), while the linker domain is required for sensing of phenolic compounds and acidity. The phosphoryl receiver domain of VirA plays an inhibitory role in signal transduction that may be modulated by phosphorylation. The carboxy terminus of the protein was also dispensable for tumorigenesis, while the periplasmic domain was required.

Agrobacterium tumefaciens↗
PubMed1992

Imaging of multiple coronary artery fistulas to right ventricle by transthoracic and transesophageal echocardiography.

A 20-year-old woman presented with extremely rare multiple coronary artery fistulas with left circumflex and right coronary arteries as the feeding vessels and two distinct sites of drainage into the posterior wall of the right ventricle near the apex in close proximity. The large left fistula was well depicted by transthoracic echocardiography, whereas the transesophageal approach better delineated part of the smaller right fistula.

Adult↗
PubMed1992

Use of indomethacin in the prophylaxis of ureteral colic following extracorporeal shock wave lithotripsy.

Ureteral obstruction leading to pain seems to be related to an increase of renal prostaglandins (PG). We designed a prospective double-blind, placebo controlled protocol for evaluating the effect of indomethacin, a PG-synthetase inhibitor, in the prophylaxis of ureteral colic following extracorporeal shock wave lithotripsy (ESWL). Sixty patients undergoing ESWL were randomized into two groups, group 1 (study group) received 50 mg indomethacin capsule three times daily and group 2 (control group) received multiple-vitamin tablet three times daily. Twenty-four hours urine samples were collected before and three days after ESWL was performed for PGE2 (predominant renal PG) determination. Subjective pain after ESWL was recorded with pain score (0-10 degrees). Oral codein or pethidine injection were available for relieving pain following ESWL. The pain score, analgesic requirement and urinary PGE2 in pre- and post-ESWL were used to compare the two groups. The pain score was 4.00 +/- 0.25 and 3.00 +/- 0.25 in the control and study groups respectively; it had a statistically significant difference (p < 0.01). In control group, 12 and 14 patients required 23 doses of codein and 18 doses of pethidine. In the study group, three and four patients required five doses of codein and eight doses of pethidine. The difference was statistically significant (p < 0.05). In the control group, the mean pre- and post-ESWL urinary PGE2 was 305 +/- 65.8 and 474 +/- 101 micrograms/24-hr respectively. In the study group, the mean pre- and post-ESWL urinary PGE2 was 289 +/- 60.7 and 186 +/- 26.5 micrograms/24-hr respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

A simultaneous bilateral attack of infectious corneal ulcers in an extended-wear soft contact lens wearer: a case report.

A case study was made of a 23-year-old female with simultaneous bilateral infectious corneal ulcers related to extended-wear soft contact lenses. Cultures revealed Pseudomonas aeruginosa and Acinetobacter calcoaceticus. Multiple high risk factors were combined, including extended-wear, poor lens care, bilateral alternate wearing, and smoking. Amphetamine addiction may also have played a role. After treatment, a visual acuity of 20/20 was achieved in both eyes by the use of rigid gas-permeable contact lenses.

Adult↗
PubMed1992

[A comparison of transrectal fine needle aspiration and biopsy of prostatic lesion].

Transrectal fine needle aspiration and biopsy were performed on 100 patients with suspicious prostatic lesions using 22 gauge aspiration needles and 18 gauge biopsy needles. These collections were made from January 1990 to June 1991. Sufficient prostate tissue for cytological and histological diagnosis were obtained in 97% (97/100) and 99% (99/100), respectively. Thirty-nine patients (39%) were diagnosed having cancer with an accuracy rate of 89.7% (35/39) by histology and 69.2% (27/39) by cytology. One patient with a normal cytological aspiration was found to have an atypical biopsy, therefore, the biopsy was repeated and the prostate showed adenocarcinoma. Our results indicate that the needle aspiration cytology has a less accurate diagnosis rate than the needle biopsy histology. Fine needle aspiration is a safe and effective outpatient procedure but there is a definite learning curve before its use can be fully exploited. It is important to have experienced urologists and pathologists to perform these aspirations until sufficient experience is accumulated.

Aged↗
PubMed1992

Results of Senning operation for transposition of great arteries.

We report our results with 10 infants and children who underwent atrial repair using the Senning operation between 1985 and 1990. All cases had abdominal situs solitus, levocardia and atrio-ventricular concordance (D-bulboventricular loop). Nine patients had simple D-transposition of the great arteries without ventricular septal defects (VSD) or left ventricular outflow tract obstruction. The other patient had a double outlet right ventricle with subpulmonic VSD and pulmonary hypertension (PHT) and underwent a palliative Senning procedure. All patients had a balloon atrial septostomy (BAS) before surgery, except for one with Taussig-Bing syndrome. One patient had a Blalock-Hanlon operation after BAS. The age at the time of surgery ranged from two months to four years seven months (mean: 22 months) and weight ranged from 4.3-12 kg. There were two hospital mortalities including the patient with VSD and PHT. All of the patients had echocardiographic examinations and six of the eight survivors received cardiac recatheterization four to 19 months (mean: 7.4 months) postoperatively. No baffle leaks were noted in the survivors. Two patients had both mild tricuspid regurgitation and slightly decreased right ventricular contractility, and one patient had a pressure gradient of 6 mmHg between the superior vena cava and neo-right atrium. The clinical follow-up interval was eight to 64 months (mean: 31.4 months). All survivors showed a sinus rhythm on their latest electrocardiogram and were participating in normal daily activities without medication.

Child, Preschool↗
PubMed1992

Pelvic actinomycosis with colo-ileo-vesical fistula formation: report of a case.

Pelvic actinomycosis with multiple fistular formation is rarely reported in the literature. We herein present a case of pelvic actinomycosis with sigmoid colo-ileovesical fistulae in a 36-year-old intrauterine device (IUD) user. She was admitted to the hospital because of general malaise, weight loss and bilateral palpable adnexal masses. Sonography showed bilateral adnexal masses which contained many echolucent spots. A barium enema examination revealed sigmoid colo-ileo-vesical fistulae. A computed tomographic scan showed bilateral cystic adnexal masses, bilateral hydronephrosis and hydroureter. Preoperatively, pelvic malignancy was suspected. An exploratory laparotomy was performed. Bilateral tubo-ovarian abscesses with extensive adhesions were found. Pathologic examination of the operative specimen revealed pelvic actinomycosis. The patient was treated with penicillin for 14 weeks and had a stable clinical course.

Actinomycosis↗