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Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 523 records · Page 29Linked to original sources
PubMed1988

Surgical treatment of supracristal type of ventricular septal defect.

Surgically treated ventricular septal defect (VSD) was of supracristal type in 120 of 389 Chinese patients; 93 of the 120 were younger than 15 years. Concomitant aortic anomalies were present in 58 of the patients (regurgitation in 23 and cusp prolapse in 35). Corresponding figures among the 93 patients of the under-15 group were 40 (9 + 31). Direct suture or patch closure of the supracristal VSD and replacement or plication of anomalous aortic valves were the methods used. The results of direct closure were equal to those of patch closure. One patient died of subacute bacterial endocarditis, which had been present preoperatively. There were no other deaths. The postoperative observation period was 6 months to 7 years. As the incidence of associated valvulopathy increases with patient age, early operation for supracristal VSD, regardless of shunt volume, is advocated.

Adolescent↗
PubMed1988

Combined modality approach to treatment of malignant gliomas--re-evaluation of RTOG 7401/ECOG 1374 with long-term follow-up: a joint study of the Radiation Therapy Oncology Group and the Eastern Cooperative Oncology Group.

The Radiation Therapy Oncology Group (RTOG) and the Eastern Cooperative Oncology Group (ECOG) conducted a phase III trial in patients with malignant gliomas to evaluate 4 treatment arms: 1) 60 Gy to the whole brain; 2) 60 Gy plus 10-Gy boost; 3) 60 Gy plus carmustine (BCNU); and 4) 60 Gy plus semustine plus dacarbazine. Between September 1974 and March 1979, 626 patients with malignant gliomas were treated on protocol RTOG 7401/ECOG 1374. Each institution chose a subset of the treatments to which the patients would be randomized. Patients were stratified according to subset and randomized to the 4 treatment arms. There were no differences in survival among treatment arms. For patients greater than 60 years of age, the addition of chemotherapy to radiation therapy did not improve survival. For patients aged 40-60 years, there was a statistically significant increase in overall survival when BCNU was added to 60 Gy (P less than .01), with an increase in 2-year survival from 8% to 23%. This beneficial effect of BCNU is apparent in both histological groups (astrocytoma with atypical or anaplastic foci and glioblastoma multiforme). Although few confirmatory autopsies are available, long-term survival in patients with astrocytomas with atypical and anaplastic foci who were treated with 60 Gy plus BCNU (5-yr survival, 22%) suggests no significant late CNS toxicity, compared to 60 Gy alone (5-yr survival, 15%). This is confirmed by comparable neurological function in long-term survivors.

Adult↗
PubMed1988

Biliary sludge-cast formation following liver transplantation.

The development of biliary sludge, in the absence of anastomotic obstruction in the common bile duct, has become a very rare complication following orthotopic liver transplantation since the adoption of modern techniques of biliary reconstruction and routine biliary flushing before cold preservation. We describe the successful treatment of this serious complication in an 18-year-old woman whose biliary sludge aggregated into firm casts occupying the extrahepatic and intrahepatic bile ducts causing obstruction and cholangitis necessitating operative intervention followed by interventional radiological approaches to treat the intrahepatic bile duct strictures. Postoperative choledochofiberscopy was also used to remove the retained biliary casts. The pathogenesis of biliary sludge appeared to be multifactorial, but cold ischemic damage to the bile duct wall seemed to play an important role in this case.

Adolescent↗
PubMed1987

Proposed mechanism of therapeutic selectivity for 9-beta-D-arabinofuranosyl-2-fluoroadenine against murine leukemia based upon lower capacities for transport and phosphorylation in proliferative intestinal epithelium compared to tumor cells.

Studies have examined transport and phosphorylation of 9-beta-D-arabinofuranosyl-2-fluoroadenine (F-Ara-A), a deaminase resistant adenosine analogue, as mechanisms that could mediate the observed therapeutic efficacy of this agent against murine tumor models. Earlier finds by Avramis and Plunkett (Cancer Res., 42: 2587-2591, 1982) showed markedly less accumulation in vivo of administered F-Ara-A as cytotoxic triphosphate in gastrointestinal mucosa and bone marrow compared to P388 cells. We have pursued the basis for this difference in vitro using L1210 ascites and proliferative epithelial cells (85-95% crypt cells) isolated from mouse small intestine as representative sample populations of drug-sensitive tumor and drug-limiting normal regenerative host tissue. Using a rapid sampling technique, linear initial rates of substrate uptake were established at 25 degrees C for radiolabeled F-Ara-A and adenosine at a concentration range of 1-1000 microM. The relationship between velocity of initial transport and substrate concentration is indicative of Michaelis-Menten saturation kinetics for both substrates. Competition studies between F-Ara-A and adenosine suggest a common route of entry for both substrates in crypt epithelial cells. Results from double-reciprocal analysis of the velocity versus concentration data are consistent with a simple carrier-mediated facilitated diffusion process with Km, V25max, and Ki values of 317 +/- 44 (SE) microM, 49 +/- 7 nmol/s/g dry weight, and 301 +/- 34 microM for F-Ara-A, and 264 +/- 14 microM, 44 +/- 5 nmol/s/g dry weight, and 225 +/- 44 microM for adenosine, respectively. The presence of a single low-affinity carrier in the proliferative epithelial cells contrasts sharply with the high affinity (Km, 68 +/- 14 microM; V25max, 48 +/- 4 nmol/s/g dry weight) and low-affinity (Km, 326 +/- 48 microM; V25max, 124 +/- 44 nmol/s/g dry weight) routes of entry documented for L1210 cells. This differential in transport kinetics conveys a 7- to 8-fold greater capacity to L1210 ascites compared with crypt epithelial cells for uptake of the antitumor agent F-Ara-A. At pharmacologically achievable concentrations of F-Ara-A and in view of this differential, influx of F-Ara-A would be more rate limiting to phosphorylation of F-Ara-A in epithelial cells than in L1210 cells. Metabolism studies with L1210 ascites and proliferative intestinal epithelial cells show that intracellular phosphorylation of F-Ara-A is also elevated in L1210 cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Multiple primary neoplasms in association with prostate cancer in black and white patients.

The current study follows up the 983 patients who were diagnosed as having prostate cancer at the Columbia-Presbyterian Medical Center in New York City between 1970 and 1979 and of whom 106 (11.5%) developed a multiple primary malignant neoplasm (MPMN) in addition to their prostate cancer by January 1, 1986. Of the 283 black patients, 32 (11.3%) developed an MPMN involving 35 sites excluding prostate. Of the 636 white patients, 74 (11.6%) developed an MPMN in association with their prostate cancer. Comparing observed incidence rates to expected on the basis of SEER incidence data, two malignant tumors, urinary bladder cancer and malignant lymphoma, appeared to occur in excess in the present series of patients. The excess of urinary bladder cancer in our series could be explained by detection bias due to the routine use of cystoscopy. The excess incidence of lymphoma in our series appears significant but its etiology is unexplained.

Adult↗
PubMed1987

Localization of a r-protein gene within the chloroplast DNA replication origin of Chlamydomonas.

In our previous study of chloroplast (Cp) DNA replication in Chlamydomonas reinhardtii, one D-loop site with its flanking regions was cloned and sequenced. The D-loop site mapped by electron microscopy (EM) overlaps with an open reading frame (ORF) potentially coding for a polypeptide of 136 amino acids. In this report, the corresponding D-loop isolated from another species of Chlamydomonas was sequenced. An ORF was also detected. Sequence comparison indicated that most conserved sequences between these two cloned origins are located within the ORF. Amino acid sequences of these two ORFs are highly conserved. The corresponding sequence for this ORF in the tobacco Cp genome was located by a Southern blotting analysis. Since the complete sequence data of Cp DNAs from a liverwort and from tobacco have been determined in 2 Japanese laboratories recently, it has been possible for us to show that this ORF encodes a protein homologous to the Cp ribosomal protein (r-protein) L16, by sequence comparison.

Amino Acid Sequence↗
PubMed1987

A comparison of misonidazole sensitized radiation therapy to radiation therapy alone for the palliation of hepatic metastases: results of a Radiation Therapy Oncology Group randomized prospective trial.

Between May 1980 and July 1983, the RTOG conducted a randomized prospective study comparing external radiation therapy and misonidazole to radiation therapy alone for patients with hepatic metastases. Two hundred fourteen patients were accessioned to this study of whom 187 were evaluable. Radiation therapy was delivered to the whole liver to a dose of 21.0 Gy in 7 fractions. Misonidazole was administered orally, 1.5 gm/m2 daily 4-6 hr before each treatment. Patients in the two treatment groups were evenly distributed with respect to stratification variables including primary site, extent of metastatic disease, and Karnofsky Performance Score (KPS). End points examined included amelioration of hepatic pain, improvement of KPS and alkaline phosphatase, decrease in liver and tumor size, and survival. The addition of misonidazole did not significantly improve the therapeutic response to radiation therapy in any of the parameters studied. Hepatic irradiation was effective in relieving abdominal pain with 80% of the symptomatic patients achieving improvement following therapy. Pain was completely relieved in 54% of these patients. Patients with liver metastases from colon carcinoma improved more frequently than those with metastases from other primary tumor sites (p = 0.02). Relief of pain occurred more frequently in patients treated with radiation therapy and misonidazole (87%) compared with radiation therapy alone (74%) (p = 0.08). Palliation of pain was prompt, occurring within a median of 1.7 weeks from the initiation of treatment, and 94% of patients who improved did so within 6 weeks of treatment. The median duration of response was 13.0 weeks in the symptomatic patients; 52% of those surviving 3 months remained improved. KPS improved in 28% of patients. Serial CT scans revealed a partial response in 7% and a marginal response in 13% of patients. One patient had a complete response to treatment. The median survival of patients treated in this series was 4.2 months with no difference between the two treatment groups. Patients with metastases from colon carcinoma and an initial KPS of 80 or more (48% of the patient population) had a median survival of 5.8 months with radiation therapy alone compared with 6.6 months with radiation therapy and misonidazole (p = 0.36). There was no significant treatment related morbidity. Radiation therapy remains an excellent palliative tool for the management of patients with symptomatic hepatic metastases. Further research must continue to identify new methods of selectivity enhancing the tumor response to radiation therapy.

Alkaline Phosphatase↗
PubMed1987

Lymphoblastic lymphoma presenting as a huge intracavitary cardiac tumor causing heart failure.

A huge intracavitary cardiac tumor causing heart failure in a 13-year-old girl was detected by two-dimensional echocardiography and was successfully resected to relieve her life-threatening symptoms. On pathologic examination, the tumor was found to be a nonconvoluted lymphoblastic lymphoma of B-cell lineage rather than a myxoma. This case is reported because of its rarity and unusual mode of growth and presentation, and illustrates that lymphoma should be included in the differential diagnosis of pedunculated cardiac tumors, especially in young individuals. The precise cytologic diagnosis of non-Hodgkin's lymphoma is important because chemotherapy and radiotherapy may achieve palliation or control of the disease.

Adolescent↗
PubMed1987

Cardiomyopathy, mental retardation, and autophagic vacuolar myopathy.

Two brothers had nonobstructive hypertrophic cardiomyopathy, mental retardation, and vacuolar myopathy, and their mother died of cardiopathy at age 31. Seven families with this syndrome have been described; heredity appears to be X-linked dominant or autosomal dominant, with different expressivity in males and females. The biochemical cause of this lysosomal storage disease is unknown.

Adolescent↗
PubMed1987

Isolated right-sided patent ductus arteriosus in right-sided aortic arch. Report of two cases.

An isolated right-sided patent ductus arteriosus has not been reported previously to occur in right-sided aortic arch associated with an aberrant left subclavian artery. We report such anomalies in two adult patients. In the first case of a 19-year-old woman, the ductus was successfully ligated via a left posterolateral thoracotomy; however, many technical difficulties were encountered. In the second case of a 36-year old woman, a right posterolateral thoracotomy enabled detailed demonstration of the ductus and its surrounding structures and facilitated its successful ligation. An isolated right-sided patent ductus arteriosus should be approached via right thoracotomy.

Adult↗
PubMed1987

Fiberoptic bronchial blockade in a small bronchopleural fistula.

A patient with bronchopleural fistula was successfully treated by selective intrabronchial injection of doxycycline and blood under fiberoptic bronchoscopic guidance. This simple and relatively noninvasive therapeutic approach is an effective and safe alternative in treating selective patients with a bronchopleural fistula.

Blood↗
PubMed1987

A digital radiology imaging system: description and clinical evaluation.

We have successfully interfaced an advanced microcomputer system to a 47-cm image intensifier for direct digital radiology. Our development effort has included the design and construction of hardware and the implementation of software. The system matrix (spatial resolution) is 1024 X 1024 and contrast resolution is 8 bits deep. A receiver-operator-characteristic analysis comparing conventional and digital laser chest radiographs for the detection of lung nodules demonstrated no statistical difference. Dosimetry measurements identified decreased patient dose. The intensifier-based digital imaging system is being increasingly used for a variety of examinations including IV pyelograms, all kinds of barium studies, and skeletal, trauma, and chest studies. Hard-copy laser-printed digital images with "bones black" are preferred by the radiology staff and have been well accepted by referring clinicians.

Evaluation Studies as Topic↗