Biomedical subjects

C H Chang

Publications and source records attributed to C H Chang.

At least 487 records · Page 27Linked to original sources

PubMed1989

Genetic and developmental regulation of the lipoprotein lipase gene: loci both distal and proximal to the lipoprotein lipase structural gene control enzyme expression.

We report here a study of the developmental and genetic control of tissue-specific expression of lipoprotein lipase, the enzyme responsible for hydrolysis of triglycerides in chylomicrons and very low density lipoproteins. Lipoprotein lipase (LPL) mRNA is present in a wide variety of adult rat and mouse tissues examined, albeit at very different levels. A remarkable increase in the levels of LPL mRNA occurs in heart over a period of several weeks following birth, closely paralleling developmental changes in lipase activity and myocardial beta-oxidation capacity. Large increases in LPL mRNA also occur during differentiation of 3T3L1 cells to adipocytes. As previously reported, at least two separate genetic loci control the tissue-specific expression of LPL activity in mice. One of the loci, controlling LPL activity in heart, is associated with an alteration in LPL mRNA size, while the other, controlling LPL activity in adipose tissue, appears to affect the translation or post-translational expression of LPL. To examine whether these genetic variations are due to mutations of the LPL structural locus, we mapped the LPL gene to a region of mouse chromosome 8 using restriction fragment-length polymorphisms and analysis of hamster-mouse somatic cell hybrids. This region is homologous to the region of human chromosome 8 which contains the human LPL gene as judged by the conservation of linked genetic markers. Genetic variations affecting LPL expression in heart cosegregated with the LPL gene, while variations affecting LPL expression in adipose tissue did not. Furthermore, Southern blotting analysis indicates that LPL is encoded by a single gene and, thus, the genetic differences are not a consequence of independent regulation of two separate genes in the two tissues. These results suggest the existence of cis-acting elements for LPL gene expression that operate in heart but not adipose tissue. Our results also indicate that two genetic mutations resulting in deficiencies of LPL in mice, the W mutation on chromosome 5 and the cld mutation on mouse chromosome 17, do not involve the LPL structural gene locus. Finally, we show that the gene for hepatic lipase, a member of a gene family with LPL, is unlinked to the gene for LPL. This indicates that combined deficiencies of LPL and hepatic lipase, observed in humans as well as in certain mutant strains of mice, do not result from focal disruptions of a cluster of lipase genes.

Adipose Tissue↗

PubMed1989

A new isotopic assay for purine nucleoside phosphorylase.

We have developed a new assay for purine nucleoside phosphorylase which is based on the release of tritium when [2-3H]inosine is used as the substrate and the reaction is coupled with xanthine oxidase. After the reaction is terminated, residual [2-3H]inosine is adsorbed on charcoal and the supernatant solution is assayed for radioactivity by liquid scintillation spectrometry. The new method gave results indistinguishable from those obtained by spectrophotometric determination of uric acid produced by the phosphorylase-xanthine oxidase-coupled reaction or by radioassay of chromatographically isolated [8-14C]hypoxanthine when [8-14C]inosine was used as substrate. The new method is faster than those involving chromatographic isolation of products. In comparison with spectrophotometric methods, it not only requires less manual time, but it also has the advantage that it can be used to study inhibitors whose ultraviolet absorption might interfere with spectrophotometric determination of uric acid.

Animals↗

PubMed1989

Use of a total wash-out method in an open heart operation.

Pathological cold agglutinins may induce hemolysis in patients who need hypothermic cardiopulmonary bypass and blood transfusion. A simple technique, termed the total wash-out method, was used in a patient with high thermal amplitude, moderate-titer cold agglutinin before hypothermic cardiopulmonary bypass. The patient's cold agglutinin titer decreased abruptly after operation. None of the preoperative hemolysis phenomena were found during her 6 months of follow-up.

Agglutinins↗

PubMed1989

Radiation Therapy Oncology Group (RTOG) survival data on anaplastic astrocytomas of the brain: does a more aggressive form of treatment adversely impact survival?

The RTOG has sponsored several studies for malignant gliomas of the brain that have included tumors classified as either glioblastoma multiforme (GBM) or anaplastic-atypical astrocytoma (AAF) under the Nelson schema. Glioblastoma multiforme, the more aggressive histology, has done poorly under all forms of treatment having a typical median survival of 8-11 months. The less common and less aggressive anaplastic-atypical astrocytoma seems to show a survival that worsens with treatment more aggressive than standard radiotherapy. All patients in this report have had their tumors centrally reviewed by a RTOG neuropathologist and have had the diagnosis of anaplastic-atypical astrocytoma confirmed. We compare three patient groups: standard photon radiotherapy from the 60 and 70 Gy arms of RTOG 74-01/ECOG 1374 and from the 65 Gy control arm of RTOG 76-11; radiation therapy and chemotherapy from RTOG 74-01/ECOG 1374 (60 Gy + BCNU and 60 Gy + MeCCNU + DTIC) and from RTOG 79-18 (60 Gy + BCNU); and photon irradiation plus a neutron boost from RTOG 76-11 and RTOG 80-07. There are 47 analyzable cases treated with photons alone, 78 analyzable cases treated with photons + chemotherapy, and 38 analyzable cases treated with photons + neutron boost. Median survival for the three groups of patients is, respectively, 3.0 years, 2.3 years, and 1.7 years. Actuarial survival curves are presented for each subgroup of patients and then for the patient subgroups further broken down by major prognostic variables--age and Karnofsky performance status. In each "better prognostic category," the median survival decreased as the "aggressiveness" of the treatment increased. The implications of these findings for future clinical trials is discussed.

Adolescent↗

PubMed1989

Transatrial membranotomy for Budd-Chiari syndrome.

In a 7-year period, transatrial membranotomy was performed in 11 patients with membranous obstruction of the inferior vena cava. There were 5 men and 6 women, ranging in age from 23 to 53 years. Clinical symptoms included jaundice in 4 patients, hepatomegaly in 4, leg edema or varicose veins in 10, and venous collaterals over the abdominal and chest wall in all 11 patients. Transatrial membranotomy was performed through a median sternotomy in all patients. When inferior vena cava venography revealed that the obstruction was accompanied by long segmental thrombosis, additional dilation was performed with a Hegar dilator. There was no surgical mortality. Early operative complications included pulmonary embolism in 2 patients and bleeding requiring reoperation in 1. In a mean follow-up period of 30.6 months (range, 2 to 88 months), 9 patients had no symptoms, transient pericardial constriction developed in 1 patient and resolved 1 month later, and restenosis of the inferior vena cava developed in another patient 1 year after the first operation. This latter patient received a second transatrial membranotomy followed by percutaneous balloon angioplasty of the inferior vena cava, with a satisfactory result at 8 months follow-up. We conclude that transatrial membranotomy is an effective and safe procedure for patients with membranous obstruction of the inferior vena cava.

Adult↗

PubMed1989

Adult Hirschsprung's disease.

This report presents a series of 17 patients with adult Hirschsprung's disease treated at the National Taiwan University Hospital and its affiliated hospitals from 1965 to 1988. Adults with Hirschsprung's disease may present with symptoms and operative findings different from those of children with Hirschsprung's disease. The symptoms, signs, criteria for diagnosis, operative findings, and operative procedures are presented.

Adolescent↗

PubMed1989

Impotence evaluated by the use of prostaglandin E1.

We screened 80 patients at our hospital for the differential diagnosis of impotence using intracavernous injection of prostaglandin E1 (20 micrograms). The rate of positive response was 78.8 per cent (63 patients). Neither systemic reactions nor priapism occurred. However, a considerable incidence (23.8 per cent, 19 of 80 patients) of tolerable injection pain was encountered. The 133xenon penile washout study was conducted routinely in impotent men for hemodynamic evaluation of penile vascularity. In 80 patients a positive correlation between the response of intracavernous prostaglandin E1 injection and the result of the washout study was found (r equals 0.381, p less than 0.0002). We selected 14 subjects randomly to receive additional intravenous infusions of prostaglandin E1 (6 ampules, 120 micrograms total) for 3 days, after which another 133xenon washout study was done. The washout studies before and after intravenous prostaglandin E1 infusion were compared, and 10 patients (71.4 per cent) appeared to obtain improvement in half-time clearance and penile blood flow. However, only 3 patients noticed improvement subjectively. We suggest that prostaglandin E1 could be a desirable alternative for the diagnosis and treatment of impotence.

Adult↗

PubMed1989

Fetal hepatoblastoma presenting as nonimmune hydrops.

The list of conditions associated with nonimmune hydrops fetalis has been steadily increasing. We describe a liveborn neonate with fetal hepatoblastoma presenting as nonimmune hydrops. The hepatic tumor was diagnosed on prenatal ultrasound. The infant survived for 2 days. The pathophysiology of nonimmune hydrops in this case is also described.

Carcinoma, Hepatocellular↗

PubMed1989

Correlation of paramagnetic states and molecular structure in bacterial photosynthetic reaction centers: the symmetry of the primary electron donor in Rhodopseudomonas viridis and Rhodobacter sphaeroides R-26.

The orientation of the principal axes of the primary electron donor triplet state measured in single crystals of photosynthetic reaction centers is compared to the x-ray structures of the bacteria Rhodobacter (Rb.) sphaeroides R-26 and Rhodopseudomonas (Rps.) viridis. The primary donor of Rps. viridis is significantly different from that of Rb. sphaeroides. The measured directions of the axes indicate that triplet excitation is almost completely localized on the L-subunit half of the dimer in Rps. viridis but is more symmetrically distributed (approximately 63% on the L half of the special pair and approximately 37% on the M half) on the dimeric donor in Rb. sphaeroides R-26. The large reduction of the zero field splitting parameters relative to monomeric bacteriochlorophyll triplet in vitro suggests significant participation of asymmetrical charge transfer electronic configurations in the special pair triplet state of both organisms (approximately 23% in Rps. viridis and approximately 13% in Rb. sphaeroides).

Bacterial Proteins↗

PubMed1989

Age-related differences in the spontaneous and thyrotropin-releasing hormone-stimulated release of prolactin and thyrotropin in ovariectomized rats.

Effect of estradiol on the spontaneous and thyrotropin-releasing hormone (TRH)-stimulated release of prolactin (PRL) and thyrotropin (TSH) in young and aged ovariectomized (Ovx) rats was investigated. Old (22-26 months) and young (3 months) female rats were Ovx 3 weeks before use. They were injected subcutaneously with estradiol benzoate (EB, 25 micrograms/kg) or sesame oil for 3 days and were catheterized via the right jugular vein. Twenty hours after the last administration of EB, rats were injected with TRH (10 micrograms/kg) through the catheter. Blood samples were collected before and 5, 10, 20, 40 and 60 min after TRH injection. On the day following blood sampling, all rats were decapitated. The anterior pituitary glands (APs) were excised, and incubated with or without TRH (10 ng/ml) at 37 degrees C for 30 min. The basal level of PRL concentration in plasma samples was 5-fold higher in old Ovx rats than in young Ovx rats. Five min after TRH injection, the increase in plasma PRL was greater in old animals than in young animals. Plasma PRL remained higher in old animals than in young animals at 10, 20, 40 and 60 min following TRH challenge. Administration of EB to old and to young Ovx rats produced increases in both basal and TRH-stimulated secretions of PRL, but did not affect the difference in plasma PRL patterns between old and young animals. The release of PRL from APs was increased significantly in all rats after a 30-min incubation with TRH. In Ovx rats injected with oil, the basal release of PRL in vitro was increased with age.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1989

A report-coding system for integration into a digital radiology department.

Report-coding systems allow the radiologist to generate a typewritten radiographic report with a computer. Typically, the report is generated by selecting bar codes, speaking key words, or selecting items on a screen. MAMM REPORT is a report-coding system for mammography, developed by radiologists, that runs on a microcomputer (Amiga, Commodore Co., West Chester, PA). MAMM REPORT speaks questions to the radiologist, who responds by pressing one of two buttons on a computer mouse, thus generating the report. MAMM REPORT allows labeling of digital images and reduction of data required to store the report in computer memory (data compression). Data compression is useful for improving computer operating speed. Digital image labeling and data compression facilitate use of MAMM REPORT on a future digital radiology workstation for an all-digital radiology department. Sixty mammographic reports, reviewed by a radiologist who is not a specialist in mammography, were entered into MAMM REPORT. The mammography specialists who dictated the original reports then judged whether the reports generated by MAMM REPORT would be acceptable replacements on the basis of descriptions of findings, diagnoses, and recommendations for further study. Data compression was measured by calculating the ratio of the number of bytes for storage of the reports in original form to a standard storage form (Huffman encoding) and to the MAMM REPORT coded form. All 60 coded reports were acceptable replacements for the original reports. For computer storage, MAMM REPORT produced a compression ratio of 135 to 1 and Huffman encoding, 1.1 to 1. Huffman encoding did not compress most reports because of their brevity. The results indicate that report coding can produce data compression of radiographic reports. The standard method of text storage, Huffman encoding, is not suitable for application to mammographic reports, which tend to be brief.

Electronic Data Processing↗

PubMed1989

Primitive neuroectodermal tumor of the brain associated with malignant rhabdoid tumor of the liver: a histologic, immunohistochemical, and electron microscopic study.

A 14-day-old white male, born with a large primitive neuroectodermal tumor of the left cerebral hemisphere, was found to have a solitary rhabdoid tumor in the liver incidentally at autopsy. Cells resembling the liver rhabdoid cells were also found by histology, immunohistochemistry, and electron microscopy in the brain tumor. The concurrence of rhabdoid cells in the tumors of the brain and liver suggests a common histogenesis and further supports the previous suggestion that the rhabdoid tumor is of neuroectodermal origin. The rhabdoid tumor in the liver in this case is likely to be a metastatic tumor from the brain rather than a second primary tumor.

Brain Neoplasms↗

PubMed1989

Echocardiographic findings of mobile atrial hepatocellular carcinoma. Report of five cases.

Hepatoma with cardiac metastasis is difficult to diagnose antemortem. Herein we describe five cases of hepatoma with intracardiac metastasis detected with two-dimensional echocardiography (2DE). The clinical presentations include cardiac murmur, syncope, and chest pain. The 2DE demonstrated a right atrial (RA) mass in each case and the presence of tumor echoes in the inferior vena cava connecting with the RA mass in four. In three cases the cardiac tumor was removed, whereas the other two patients agreed only to liver biopsy, which confirmed the diagnosis. This paper emphasizes the practical utility of 2DE for early detection of intracardiac hepatoma and also describes the clinicopathologic correlation of such a disease entity.

Adult↗

PubMed1989

A newly isolated avian sarcoma virus, ASV-1, carries the crk oncogene.

Avian sarcoma virus 1 (ASV-1) was isolated from a spontaneous sarcoma of an adult chicken. It is a replication-defective virus that induces fibrosarcomas in young chickens and oncogenic transformation in cultured chick embryo fibroblasts. The ASV-1 genome has been cloned in the lambda gt WES.lambda B vector from closed circular viral DNA extracted from infected cells. The nucleotide sequence of the oncogene insert in the ASV-1 genome has been determined. It is virtually identical to the sequence of the oncogene crk recently discovered in the avian sarcoma virus CT10. ASV-1 and CT10 are two independent retrovirus isolates carrying the crk oncogene.

Amino Acid Sequence↗

PubMed1989

Kidney biopsy in SLE. I. A clinical-morphologic evaluation.

The relationship between renal morphology and clinical disease was analysed in 148 patients with SLE attending a lupus clinic. Patients were not selected for renal disease. Renal tissue was assessed according to the World Health Organization classification of lupus nephritis, the presence of active and chronic lesions was recorded and disease activity was measured according to a standard protocol. All sections of the classification were represented in this group of patients. Active and chronic lesions were more likely to occur among patients with Class III/IV (proliferative glomerulonephritis), than in any other category. Patients with Class III/IV biopsy were more likely to have evidence of clinical renal disease than patients in Class II (mesangial). However, almost half of the Class II patients had some evidence of renal disease, including elevated serum creatinine, as well as important non-glomerular lesions. Without biopsy they might have been thought to have proliferative lesions and been treated more aggressively. Two patients with proliferative glomerulonephritis had no clinical evidence of renal disease. Thus, at the time of biopsy results renal histological examination did not uniformly correlate with clinical renal disease.

Adolescent↗

PubMed1989

Comparison of penile vascular effect induced by intracavernous injection of papaverine and prostaglandin E1.

An intracavernous injection with papaverine or prostaglandin E1 (PGE1) combined with duplex ultrasonography is an objective technique to conduct a penile blood flow study (PBFS). Three hundred patients with impotence underwent papaverine (9-60 mg) induced PBFS at the University of California School of Medicine, San Francisco (UCSF), U.S.A. and another 80 patients with impotence received PGE1-induced (20 micrograms) PBFS at Veterans General Hospital-Taichung (VGH-TC), R.O.C. Preliminary evaluation of age, duration of disease and pre-injection diameter of cavernous arteries disclosed no significant difference in these 2 series. It was interesting to find that almost all parameters of vascular response to pavaverine vs PGE1 differed significantly, such as onset of response (6.5 +/- 6.5 vs 11.7 +/- 6.4 min, slower in the PGE1 group, p less than 0.001); post-injection diameter of cavernous arteries (right: 0.73 +/- 0.20 vs 0.79 +/- 0.18 mm, p = 0.03; left: 0.74 +/- 0.20 vs 0.82 +/- 0.21 mm, p = 0.005); diametral increment of cavernous arteries (right: 0.23 +/- 0.17 vs 0.33 +/- 0.17 mm, p less than 0.001; left: 0.24 +/- 0.17 vs 0.36 +/- 0.19 mm, p less than 0.001) and peak velocity (right: 27.5 +/- 16.1 vs 42.0 +/- 20.1 cm/sec, p less than 0.001; left: 28.9 +/- 15.9 vs 39.7 +/- 17.9 cm/sec, p less than 0.001). The side effects, primarily injection pain (23.8%, 19/80) in the PGE1 group and dizziness (3.0%, 9/300) in the papaverine group, were minor in these 2 series. Prolonged erection was not encountered in either series; however, immediate treatment was performed if a papaverine-induced erection lasted over 60 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

Surgical management of congenital coronary artery fistula.

Over a period of 6 years, 8 patients underwent surgical treatment at our hospital for congenital coronary artery fistula (CAF). The ages of the patients ranged from 4 months to 50 years (mean 22.7 years). Continuous heart murmurs could be heard in all patients, except one. The diagnosis was made by retrograde aortography and/or selective coronary arteriography. Only one patients had associated cardiac disease. All the drainage sites of the CAF were on the right side of the heart (right atrium, right ventricle, pulmonary artery). Two patients had both right and left CAFs. Symptoms due to "coronary steal" by a coronary artery fistula were demonstrated by a nuclear medicine study in one of our patients. Four patients were operated on with the aid of cardiopulmonary bypass. The other 4 patients were treated with suture ligation directly. There was no surgical mortality or morbidity, and the longterm results have been good. Since surgical correction is safe and effective, it would appear desirable for all patients with CAF be operated on. However, surgical intervention is controversial in asymptomatic patients.

Adult↗

PubMed1989

Transrectal sonography of the prostate and seminal vesicles on patients with hemospermia.

Morphological change of the seminal tract of patients with hemospermia was determined by means of transrectal sonography on 38 patients. Twenty-seven (71%) had positive sonographic findings, including 20 prostatitis and/or seminal vesiculitis, three benigh prostatic hypertrophy, three prostate calculi and one seminal vesicle stone. Simultaneous bacteriologic study revealed positive cultures on 11 patients; 9 of whom (81%) had morphologic appearance on transrectal sonography suggesting inflammatory origin. Our experience indicates that transrectal sonography is capable of surveying the histopathologic change of the prostate and seminal vesicles, and is therefore effective in studying patients with organic hemospermia.

Adult↗