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Biomedical subjects

C J Chang

Publications and source records attributed to C J Chang.

At least 217 records · Page 12Linked to original sources
PubMed1990

Ansamitocin P-3, a maytansinoid, from Claopodium crispifolium and Anomodon attenuatus or associated actinomycetes.

Guided by cytotoxicity, ansamitocin P-3, a maytansinoid, was isolated in very low yield from two members of the moss family Thuidiaceae, Claopodium crispifolium (Hook.) Ren. & Card. and Anomodon attenuatus (Hedw.) Hueb. Ansamitocin P-3 showed potent cytotoxicity against the human solid tumor cell lines A-549, HT-29. A possible basis for the occurrence of this compound in mosses is discussed.

Actinomycetales↗
PubMed1990

Inhibitory effect of gossypol on human chorionic gonadotropin (hCG)-induced progesterone secretion in cultured bovine luteal cells.

Inhibitory effects of gossypol on the female reproductive system have been recently reported. This study investigated a possible site of gossypol action on progesterone synthesis. Bovine luteal cells were cultured with hCG and forskolin in the presence or absence of gossypol. At 10 micrograms/ml, gossypol significantly inhibited hCG- and forskolin-stimulated progesterone secretion and intracellular cAMP formation; at 20 micrograms/ml, gossypol completely abolished the stimulative effect of hCG and forskolin. The results suggest that adenylate cyclase may be a site of gossypol action on steroidogenesis of bovine luteal cells.

Animals↗
PubMed1990

16 alpha-hydroxy-(-)-kauranoic acid: a selectively cytotoxic diterpene from Annona bullata.

Using brine shrimp lethality to direct fractionation, extracts of the bark of Annona bullata Rich. (Annonaceae) have yielded 16 alpha-hydroxy-(-)-kauranoic acid as a bioactive plant constituent. This previously known diterpene showed significant (ED50 8.25 x 10(-2) micrograms/ml) and selective cytotoxicity against A-549 (lung) cells in our panel of human tumor cells.

Acetylation↗
PubMed1990

Facial bone fracture associated with carotid-cavernous sinus fistula.

Out of 989 cases of facial bone fracture, ten patients had carotid-cavernous sinus fistulas (1.01%). Their ages ranged from 25 to 48 years. Seven were male and three female. Two of the ten patients had lower third, three patients had middle third, three patients had upper third, and two patients had combined middle and lower third facial bone fractures. The signs and symptoms of a fistula appeared from the first postinjury day up to 50 days after the injury (mean, 21 days). Four patients had symptoms after operation for facial bone fracture. Most fistulae were identified by arteriography before treatment. Followup ranged from 1 year, 8 months, to 5 years, 9 months (mean, 2 years, 9 months). One patient had a malocclusion. Nine patients had complete resolution of their bruits. Complications included unilateral complete visual loss (two), CSF rhinorrhea (two), and stroke in one of the two CSF rhinorrhea patients. One patient expired due to a severe head injury, and there was one death from an unrelated cause.

Adult↗
PubMed1990

Molecular cloning of a transcription factor, AGP/EBP, that belongs to members of the C/EBP family.

A C/EBP-like transcription factor, AGP/EBP, that binds to three distinct motifs in the 5'-flanking region of alpha 1-acid glycoprotein gene (AGP) has been identified. Here we report the cloning and properties of cDNA corresponding to mouse AGP/EBP. AGP/EBP and C/EBP share 87% amino acid sequence homology in the "leucine zipper" and its associated DNA-binding domains, while their sequences outside these domains and the sizes of their mRNAs are different. Unlike the limited expression of C/EBP in tissues and cells, AGP/EBP appears to be ubiquitously expressed in tissues like lung, spleen, kidney, heart, testis, and liver and cell lines like p388D1, 129P (hepatoma cell line of C3H/HeJ), FO (mouse myeloma), and L929. Antibody against cloned and expressed AGP/EBP which was raised in rabbits could recognize AGP/EBP from nuclear extract of a number of cells and tissues. On the basis of our findings about the structural relationship and the similarity of motif recognition, we propose that a family of C/EBP-like transcription factors exists.

Amino Acid Sequence↗
PubMed1990

A comparison of newly and previously diagnosed diabetics in Taiwan.

Between 1985 and 1986, during a population survey of diabetes in 1 urban and 5 rural areas of Taiwan, a total of 11,478 adults aged 40 or older were screened. Capillary whole blood glucose was determined with a glucometer (Ames Co.) The diabetic criteria followed the WHO designations. From this survey, a comparison of 225 newly diagnosed and 383 previously diagnosed diabetics was conducted. Multiple regression analysis revealed a highly significant correlation for all diabetics with regard to age, body mass index, family history and hypertension, but no specific correlation to habitat. Mean fasting glucose levels in previously and newly diagnosed diabetics were 172 and 158 (males 158 vs 147 and females 184 vs 165) mg/dl, respectively, which suggest that treatment is apparently inadequate in this population. The prevalent rate (%) of retinopathy for previously and newly diagnosed diabetics was 45.2 and 28.3 (males 42.8 vs 33.3 and females 47.5 vs 24.8), respectively. The prevalence is as common as those reported in western countries. In conclusion, previously diagnosed diabetics had higher fasting glucose concentrations and prevalent rates of retinopathy than newly diagnosed diabetics, and these findings were particularly prominent in females.

Adult↗
PubMed1990

[Utilization and medical cost of patients with different insurance coverage among group practice centers].

In order to explore the utilization and medical cost of patients with different insurance coverage in group practice centers, we collected patient data in three centers from September 1, 1987 to February 28, 1988. We classified the payments as self-payment,partial-reimbursement and total-reimbursement. There were 42,234 visits by 8,111 patients. The average frequency of visits within 6 months was 6.1 in total-reimbursement patients, 5.2 in partial-reimbursement patients and 2.6 in self-payment patients. We found that the frequency of visits increased with age in patients with total-reimbursement and partial-reimbursement. On the other hand, the frequency decreased after the age of 65 in patients with self-payment; whether it was related to the economic problems of the elderly needs further study. The highest medical cost per visit was NT$. 343 in total reimbursement patients, followed by NT$. 281 in partial-reimbursement patients. The lowest cost was NT$. 208 in self-payment patients. Yet, the highest ratio of total drug cost by total medical cost per visit was 73.7% in partial-reimbursement patients followed by 63.6% in total-reimbursement patients. The lowest ratio was 56.7% in self-payment patients. Although the partial-reimbursement system could not decrease the ratio of total drug cost by total medical cost per visit, it would be beneficial in group practice centers to decrease the patients' visits and the medical cost per visit. Therefore, this system should be executed in the future.

Adolescent↗
PubMed1990

A comparison of diabetic control status between urban and rural diabetic patients in Taiwan.

Between 1985 and 1987, in two urban and five rural areas in Taiwan, a total of 16,636 subjects aged 40 or over were screened for diabetes mellitus according to the WHO criteria. Four hundred and fifty-two previously diagnosed patients and 274 newly diagnosed patients were found. All were non-insulin-dependent diabetics. The blood glucose control status was compared between the urban and rural previously diagnosed diabetics. Those living in the rural areas were found to have better control with a higher percentage under regular treatment. Stepwise multiple regression failed to discover a significant correlation between control status and any of the following factors: sex, age, body mass index (BMI), diabetic duration, treatment regularity, exercise, occupation, education, family income and the presence of hypertension or large vessel diseases. About 30% of the patients in rural areas and 40% in urban areas were poorly controlled. This indicates that our diabetic control program should be strengthened.

Aged↗
PubMed1989

Molecular cloning of cDNAs corresponding to two genes of alpha 1-acid glycoprotein and characterization of two alleles of AGP-1 in the mouse.

cDNAs corresponding to two types of mouse alpha 1-acid glycoproteins (AGPs), Agp-1 and Agp-2, were cloned and sequenced. Two alleles of Agp-1 were also identified from inbred mice by restriction site polymorphisms. One allele, Agp-1A, is associated with AKR/J, SJL/J, and SWR/J mice, while the other, Agp-1B, is found in BALB/c, DBA/2, C57BL/6, B10, and A/J mice. cDNAs of both Agp-1A and Agp-1B were cloned from BALB/c and (B10 x AKR/J)F1 mice. A single nucleotide substitution in the coding sequence of Agp-1 is responsible for the observed difference in electrophoretic mobilities of Agp-1A and Agp-1B. Several additional nucleotide variations in the 3' untranslated region were also found. In contrast to these two alleles, substantial nucleotide difference exist between Agp-1 and Agp-2. Agp-1 and Agp-2 contain five and six potential N-glycosylation sites, respectively.

Alleles↗
PubMed1989

[Pulmonary artery sling: diagnosis by magnetic resonance imaging--one case report].

Pulmonary artery sling is an uncommon congenital vascular anomaly, which may cause significant respiratory morbidity resulting from an external tracheal compression during early infancy. This condition should be considered on finding a mass interposed between the trachea and the esophagus showing an anterior indentation on the esophagograms. The diagnosis is usually made by invasive methods such as bronchography, bronchoscopy, cardiac catheterization, and angiography. Magnetic resonance imaging (MRI) has now become an excellent method for diagnosing cardiovascular anomalies, but the use of MRI as a means of diagnosing pulmonary artery sling is rare. In 1988, Malmgren et al, first reported the use of MRI in three cases. Their findings suggested that two overlaping sets of axial sections might be necessary for depicting the anomaly because different parts of the left pulmonary artery are imaged in different slices. In this paper, we report a diagnostic scan image which utilizes a single axial scan and reveals the pulmonary artery sling arising aberrantly from the right pulmonary artery. We also found (a) when the pulmonary artery sling interposed between the esophagus and trachea; the trachea become stenotic below the upper one-third in LAO equivalent sagittal section; (b) the right pulmonary artery compresses the proximal part of right pulmonary bronchus, and the right upper lobe bronchus arises from the trachea independently in the coronal section. Thus, we conclude that MRI, if available, should be the first choice modality for further examination when a pulmonary artery sling is suggested by conventional radiography.

Female↗
PubMed1988

Serum deprivation of vascular smooth muscle cells enhances collagen gene expression.

Vascular smooth muscle cells produce the bulk of connective tissue protein in major arteries. Previously, we demonstrated that collagen synthesis by cultured bovine aortic smooth muscle cells in exponential growth is low and increases as cells approach confluence and growth slows. To evaluate more directly the effects of the proliferative state, subconfluent cultures of smooth muscle cells were incubated in medium supplemented with 0.5% fetal calf serum; under these conditions of growth factor deprivation, cells become quiescent within 72 h. The mRNA levels for type I and III collagens increased markedly within 12 h; at 48 h, they were between 2- and 15-fold higher than in cells growing exponentially. Upon addition of serum to quiescent cultures, cells re-entered the cycle, and collagen mRNA levels decreased. Expression of alpha 1(I), alpha 2(I), and alpha 1(III) mRNAs differed significantly, indicating differential gene regulation. In nuclear run-off assays, changes detected in collagen transcription were insufficient to account for changes in mRNA levels, suggesting additional post-transcriptional sites of control. The inverse response of collagen expression to the proliferative state suggests that exposure of smooth muscle cells in vivo to factors which influence their growth state could have profound effects on the structure of the arterial wall.

Animals↗
PubMed1988

Goniothalamicin and annonacin: bioactive acetogenins from Goniothalamus giganteus (Annonaceae).

Using brine shrimp lethality for activity-directed fractionation, goniothalamicin (I), a new tetrahydroxy-mono-tetrahydrofuran fatty acid gamma-lactone (acetogenin), has been isolated from ethanolic extracts of the stem bark of Goniothalamus giganteus Hook. f., Thomas (Annonaceae). This novel compound was found to be cytotoxic and insecticidal and inhibited the formation of crown gall tumors on potato discs. Annonacin (II), the only other reported mono-tetrahydrofuran acetogenin, was also isolated; the previously reported 9ASK (astrocytoma reversal) activity of II was confirmed, and II is now also found to be weakly active against 3PS murine leukemia.

Animals↗
PubMed1987

Annonacin, a novel, biologically active polyketide from Annona densicoma.

A new linear polyketide, Annonacin (I), has been isolated from active extracts of the stembark of Annona densicoma Mart. Annonacin (I) is highly cytotoxic and is active in an assay designed to detect antimitotic agents. The structure of (I) was determined by analysis of spectroscopic data.

Antineoplastic Agents↗
PubMed1987

Characterization of an alkylated dinucleotide by desorption chemical ionization and tandem mass spectrometry.

A highly sensitive (subpicomole level), structure-specific method of analysis has been developed for characterizing and quantitating the dinucleotide thymidylyl(3'----5')thymidine methyl phosphotriester by desorption chemical ionization tandem mass spectrometry. The methodology can be applied to related compounds such as the parent dinucleotide and employs either positive or negative ionization mass spectra or daughter spectra. The procedure allows specification of the site of methyl attachment.

Chemical Phenomena↗
PubMed1987

Effects of different heat treatments during processing on nutrient digestibility of soybean meal in growing swine.

Four soybean meals (SBM) were prepared in a commercial solvent-extraction plant to give a much wider range in heat treatment than is usually found among commercially available SBM. The meals were designated in ascending order of heat treatment as Under, Normal, Over and Rumen Escape. The Normal meal was processed using standard operating conditions. The Under meal received less heat treatment by reducing the steam pressure and retention time in the desolventizer-toaster. Over and Rumen Escape meals received further heat treatment in an additional four-compartment toaster. The Over meal received less heat treatment than the Rumen Escape meal by reducing steam pressure and retention time in both toasters. Crude protein content was similar for the four meals, but lysine tended to decrease with increasing heat treatment. In general, urease activity, trypsin inhibitor, protein dispersibility index and nitrogen solubility index decreased with increasing heat treatment. The +a Hunterlab color values increased as heat treatment increased. Apparent ileal digestibility of N and amino acids were similar for all meals (P greater than .05); however lysine digestibility for the Rumen Escape meal was 3.3 percentage units lower than the average of the lesser-heated meals. Energy digestibilities and nitrogen balance data were also similar (P greater than .05) for the four meals, but the apparent biological value of the Rumen Escape meal was 4.5 percentage units lower than the average of the other meals. There were no differences in nutritional value among the Under, Normal and Over meals, which represent the range in heat treatment usually found among SBM. The Rumen Escape meal, which received more severe heat treatment, tended to have lower nutritional value than the lesser-heated meals.

Animal Feed↗