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Biomedical subjects

C Y Yang

Publications and source records attributed to C Y Yang.

At least 199 records · Page 11Linked to original sources
PubMed1993

Pulmonary function and respiratory symptoms of Portland cement workers in southern Taiwan.

Respiratory symptoms and pulmonary function were studied in a cross-sectional survey of Portland cement workers in southern Taiwan. The study cohort consisted of 661 cement workers who were classified into low, medium, and high exposure groups with mean exposure values of 0.22, 0.55 and 1.24 mg/m3 of respirable dust concentrations, respectively. The prevalence of respiratory symptoms was not found to be significantly related to exposure, with the exception of a higher prevalence of coughing found among the heavy exposure group (OR = 1.55, P < 0.05). Both non-smoking and smoking cement workers showed no significant differences in the pulmonary function indices among the three exposure groups.

Adult↗
PubMed1993

Stimulation of PGE2 synthesis in a co-culture of periosteal fibroblasts and osteoblast-like cells by parathyroid hormone.

In previous experiments, we demonstrated that hPTH 1-34 activates PGE2 synthesis and calcium mobilization by chick calvaria. In this report, we started to search for the PTH responsible cell population in this bone tissue. When the chick calvariae were subjected to sequential enzyme digestion, we found that the third cell population were the cells that reacted to human PTH 1-34 and bovine PTH 1-34. A subsequent procedure was performed using the cells isolated from enzyme digestion and separated into two distinct populations--periosteal fibroblasts (PF) and osteoblast-like cells (OB)--by a two-step density gradient of Percoll. We found that PF and OB cells alone did not respond to PTH in terms of PGE2 synthesis. However, when these two cell populations were mixed in the proportion of 50:50, the synthesis of PGE2 and PGF2 alpha was increased significantly by the treatment of PTH and calcitonin. No effects were demonstrated in the mixing proportions of 30:70 and 70:30. These results suggest that PTH responsiveness may need a local interaction between periosteal fibroblasts and osteoblast-like cells residing in chick calvaria.

Animals↗
PubMed1993

Human very low density lipoprotein structure: interaction of the C apolipoproteins with apolipoprotein B-100.

Very low density lipoproteins (VLDL) are a heterogenous population of particles differing in size and composition. Heparin-Sepharose chromatography yields three VLDL subfractions. Two subfractions, VLDLNR-1 and VLDLNR-2, which are not retained by heparin, contain little or no detectable apolipoprotein (apo)E. According to negative stain electron microscopy, VLDLNR-1 is slightly larger than VLDLNR-2. The third fraction, VLDLR, is composed of smaller particles that are retained by the heparin-Sepharose and contain apoE. The C apolipoproteins of the respective VLDL subfractions transfer to 1-palmitoyl-2-oleoyl phosphatidylcholine (POPC) single bilayer vesicles giving three subfractions designated VLDLNR-1-C, VLDLNR-2-C, and VLDLR-C. The protein, phospholipid, and cholesterol (free + esterified) contents decrease in the order VLDLR > VLDLNR-2 > VLDLNR-1. Triglyceride content decreases in the opposite order. POPC treatment of each VLDL subfraction increases the phospholipid and decreases the protein, triglyceride, and cholesteryl ester contents, while free cholesterol remains unchanged. According to immunological analysis of each subfraction with well-characterized monoclonal antibodies, the accessibility of some epitopes of apoB-100 on VLDL is changed by POPC treatment. Electron-microscopic analysis of POPC-treated VLDL subfraction reveals vacancies on the surfaces of each particle. VLDLNR-1, VLDLNR-2, and VLDLR are resistant to thrombin cleavage, whereas the lipoproteins lacking C apolipoproteins are not. Thrombin cleavage (8 h) of apoB-100 of VLDLNR-2-C and VLDLR-C gives two fragments, T1 and T2, that are converted to smaller fragments only after prolonged treatment. In contrast, apoB-100 of VLDLNR-1-C is converted into small fragments after 8 h thrombin treatment. These results suggest that removal of apoCs affects the accessibility and conformation of apoB-100 in the individual VLDL subfractions in the region near residue 3249, which is the primary thrombin cleavage site and the epitope of monoclonal antibody 4C11.

Apolipoprotein B-100↗
PubMed1992

Plasma lipid transport in the preruminant calf, Bos spp: primary structure of bovine apolipoprotein A-I.

The preruminant calf (Bos spp.) is a model of considerable interest with regard to hepatic and intestinal lipoprotein metabolism (Bauchart et al., J. Lipid Res. (1989) 30, 1499-1514 and Laplaud et al., J. Lipid Res. (1990) 31, 1781-1792). As a preliminary step towards future experiments dealing with HDL metabolism in the calf, we have purified apoA-I from this animal and determined its complete amino acid sequence. Thus, approx. 10% of calf apoA-I was shown to contain a propeptide, with the sequence Arg-His-Phe-Trp-Gln-Gln. Enzymatic cleavage of apoA-I resulted in 10 proteolytic peptides. The complete apoA-I sequence was obtained after alignment of peptides on the basis of their homologies with those from rabbit apoA-I. Thus calf apoA-I consists of 241 amino acid residues, and exhibits high sequence homology with all mammalian apoA-I's studied to date. The bovine protein contained 10 hydrophobic amphipathic helical regions, occurring between residues 43-64, 65-86, 87-97, 98-119, 120-141, 142-163, 164-184, 185-206, 207-217 and 218-241. A computer-constructed phylogenetic tree showed that bovine apoA-I was more closely related to its dog counterpart, including the presence of a single methionine, than to the corresponding macaque and human proteins. Comparative predictions of the respective antigenic structures of human and bovine apoA-I's using the Hopp-Woods algorithm indicated similar positions for all 13 detectable antigenic sites, among which 7 were of identical, or closely related, amino acid composition. This finding was confirmed by demonstration of partial immunological identity between the two proteins upon immunodiffusion analysis, a result obtained using a monospecific rabbit antiserum against bovine apoA-I. Finally, comparison of sequence homology between bovine apoA-I and the lecithin:cholesterol acyl transferase (LCAT) activating region of human apoC-I suggests that several LCAT activating domains may be present in calf apoA-I.

Amino Acid Sequence↗
PubMed1992

The translocation (1;14)(p34;q11) in human T-cell leukemia: chromosome breakage 25 kilobase pairs downstream of the TAL1 protooncogene.

Nearly 30 percent of patients with T-cell acute lymphoblastic leukemia (T-ALL) exhibit a tumor-specific rearrangement of the TAL1 gene (also called TCL5 or SCL). These rearrangements are generated by either local DNA deletion or a (1;14)(p34;q11) chromosome translocation, and they typically result in structural alterations of the TAL1 transcription unit. In this report we present a molecular characterization of the t(1;14)(p34;q11) from a T-ALL patient. As a consequence of the translocation, TAL1 is transposed from its normal position on chromosome 1 into the T-cell receptor alpha/delta chain locus on chromosome 14. Unlike previous cases, the chromosome 1 breakpoint in this patient did not disrupt the continuity of the TAL1 transcription unit, but instead occurred approximately 25 kilobase pairs (kb) downstream of TAL1. This observation suggests that malignant alteration of TAL1 can be mediated by long-range cis-activating mechanisms that are triggered by DNA rearrangement at a distant site. Genes Chrom Cancer 4:211-216 (1992).

Base Sequence↗
PubMed1992

Antinociceptive effect of chronic nicotine and nociceptive effect of its withdrawal measured by hot-plate and tail-flick in rats.

Nicotine (6 mg/kg/day) was administered subcutaneously via Alzet osmotic pumps to rats for 28 days. Nociception was measured by the hot-plate and tail-flick methods. A significant antinociceptive effect was demonstrated during the first week of the treatment; after that tolerance developed, lasting for the remaining period of nicotine treatment. This effect was more pronounced in the habituated, rather than in the naive, rats. Rats subjected to nicotine withdrawal tended to exhibit the nociceptive effect for 10 days with an overall P value on the border of significance. This chronic nicotine-induced antinociception and nicotine withdrawal-induced nociception was detectable only by hot-plate but not the tail-flick technique.

Analgesics↗
PubMed1992

Localization of GABAA receptor subtypes in the tiger salamander retina.

Dry autoradiography was used to determine the distribution of GABAA binding sites in tiger salamander retina. High-affinity binding of [3H]-flunitrazepam [( 3H]-FNZ) was used to localize benzodiazepine receptors (BZR) and [3H]-muscimol was used to localize the GABAA recognition site. Specific [3H]-FNZ binding was present only in the inner retina, primarily in the inner plexiform layer (IPL). Co-incubation with GABA enhanced [3H]-FNZ binding by 20-50%. [3H]-muscimol binding was found throughout the IPL and in the outer plexiform layer (OPL). Mouse monoclonal antibodies 62-3G1 and BD-17, that recognize the GABAA beta 2, beta 3 polypeptides, and BD-24, that recognizes the GABAA alpha 1 polypeptide, did not label either the OPL or IPL, despite numerous variations in the fixation and immunoprocessing methods. GABAA receptor location, as revealed by [3H]-muscimol binding, matches the distribution of presumed GABAergic terminals in the OPL and IPL. We suggest that there are at least two subtypes of GABAA receptor in the tiger salamander retina: one type is present only in the inner retina, primarily in the IPL and is functionally coupled to BZRs; the other type is located in the OPL and is not coupled to the BZRs. Furthermore, GABAA receptors in the tiger salamander retina appear to be of a different epitope than GABAA receptors in numerous other preparations that are recognized by mAbs 62-3G1, BD-17, and BD-24.

Ambystoma↗
PubMed1992

Depressive symptoms and mortality in elderly persons.

Studies on the relationship between depression and mortality in elderly community populations have yielded contradictory findings, although an association frequently is found in studies of elderly psychiatric patients. These different results may be due to differences in the measures of depression, the populations under study, the covariates in the analysis, or to sample attrition. In this study of elderly residents of an urban neighborhood, depressive symptoms are measured at two time points. People are classified as consistently nonsymptomatic (N-N), with emergent symptoms (N-D), in remission (D-N), or persistently symptomatic (D-D). Symptoms of depression, sociodemographic characteristics, and measures of changes in health, functional status, number of chronic medical conditions, and social support are examined in relation to mortality in multivariate Cox regression models. Although symptoms of depression are not found to be related to time-to-death, older people, those with declines in health and functional status, and men have greater relative risks of mortality over a three-year follow-up.

Aged↗
PubMed1992

Pharmacological and pathological studies on hepatic protective crude drugs from Taiwan (V): The effects of Bombax malabarica and Scutellaria rivularis.

Bombax malabarica DC and Scutellaria rivularis B. were extracted in boiling water and concentrated into 1g/ml solution to investigate their hepatoprotective effect. Carbon tertrachloride (CCL4) was injected into rat subcutaneously with a dose of 3.0 ml/kg to induce experimental acute hepatotoxicity in the animal. The activities of serum glumtamic-oxaloacetic transaminase (SGOT) and serum glutamicpyruvic transaminase (SGPT) were measured after 72 hours of CCL4 administration. The hepatopathological changes of the liver tissue were observed simultaneously with liver enzyme activities determination. The pharmacological effect of B. malabarica and S. rivularis of Taiwan was compared with that of the Bupleurum chinense from mainland China. B malabarica (p < 0.001), S. rivularis (p < 0.001) and B. chinense (p < 0.05) all demonstrated a significant reduction in the CCL4-induced SGOT and SGPT. Pathological studies of these three drugs extracts demonstrated a marked hepato-protective effects on CCL4-induced liver fatty degeneration and cell necrosis.

Alanine Transaminase↗
PubMed1992

Identification of endogenous 5S,12S-dihydroxy-6,8,10,14-(E,Z,E,Z)-eicosatetraenoic acid (5S,12S-diHETE) in chick osteoblasts and epiphyseal cartilage.

Cell homogenates were obtained from chick osteoblast-like cells and epiphyseal growth plates. The lipid fraction was extracted with ethyl acetate and separated by RP-phase HPLC. Reverse-phase HPLC analysis of this fraction showed a major peak displayed a conjugated tetraene structure and this endogenous synthetic compound could be partially blocked by heat treatment at 100 degrees C for 5 min. After methylation, this peak was further purified by SP-HPLC and a major peak was identified by an U.V. absorption at lambda max of 271 nm and shoulders at 261 and 281 nm. The compound was hypothetically proposed by gas chromatography and mass spectrometry (GC/MS) as the cyclohexadiene derivative of 5S,12S-dihydroxy-6,8,10,14-(E,Z,E,Z)-eicosatetraenoic acid (5S,12S-diHETE) with a ring closure at C6 and C11. These results demonstrated that the 5S,12S-diHETE is an endogenous eicosanoid in both intramembranous and endochondral skeletal tissues.

Animals↗
PubMed1992

Radiological manifestations of cardiovocal syndrome.

Cardiovocal syndrome is a rare clinical diagnosis that signifies vocal cord palsy associated with various cardiovascular diseases. The radiological manifestations of six cases of clinically diagnosed cardiovocal syndrome are reviewed retrospectively. The common clinical presentation of these six cases was hoarseness that was due to left vocal cord palsy. By means of chest X-rays (CXR) and cardioangiography, four cases were respectively diagnosed to have atrial septal defect (n = 1), ventricular septal defect (n = 1) and mitral stenosis (n = 2), all of which were associated with a common radiological finding of dilatation of pulmonary trunk. The other two cases were separately diagnosed to have proximal descending aortic saccular aneurysm (n = 1) by means of CXR and angiography, and fusiform ascending aortic aneurysm (n = 1) by computed tomography and magnetic resonance image. All these radiological presentations of either aortic aneurysm or dilated pulmonary trunk were associated with encroachment of aorticopulmonary window for which the left recurrent laryngeal nerve was presumably compressed with the result of left vocal cord palsy. Hoarseness that is caused by these underlying cardiovascular diseases is correctable after treatment of the underlying diseases. Hence, clinicians and radiologists should pay attention to the radiological manifestations of patients whose chief complaints are hoarseness and cardiovocal syndrome.

Adult↗
PubMed1992

Characterization of disulfide-linked heterodimers containing apolipoprotein D in human plasma lipoproteins.

Human plasma apolipoprotein (apo) D is a glycoprotein with an apparent molecular weight of 29,000 M(r). It is present, mainly, in high density lipoproteins (HDL) and very high density lipoproteins (VHDL). Western blot analysis of HDL and VHDL using rabbit antibodies to human apoD revealed major immunoreactive bands at 29,000 and 38,000 M(r), with minor bands ranging from 50,000 to and 80,000 M(r). Only the 29,000 M(r) band corresponding to apoD remained when the electrophoresis was conducted under reducing conditions, demonstrating that apoD is cross-linked to other proteins via disulfide bonds. The broad pattern of immunoreactivity was also observed under nonreducing conditions when the blood was collected into a solution of sulfhydryl-trapping reagents, or when these reagents were added to the isolated lipoproteins. These results indicated that the disulfide bonds were not the result of disulfide exchange during the experimental procedures. On the basis of amino acid sequencing and reactions to antibodies, the 38,000 M(r) band was identified as an apoD-apoA-II heterodimer. The apoD-apoA-II was also demonstrated in plasma. In both HDL and plasma, the apoD-apoA-II heterodimer constituted the major form of apoD. Disulfide-linked heterodimers of apoD and apoB-100 were also found in low and very low density lipoproteins, and in whole plasma. It is concluded that a fraction of human apoD, like other cysteine-containing apolipoproteins, exists as a disulfide-linked heterodimer with other apolipoproteins in all major human lipoprotein fractions.

Amino Acid Sequence↗
PubMed1992

Fistulotomy and marsupialisation for simple fistula-in-ano.

Nineteen consecutive cases of simple fistula-in-ano treated with fistulotomy and marsupialisation were retrospectively reviewed. Fourteen cases were simple intersphincteric and the remaining 5 cases were uncomplicated transphincteric fistulae. The cases were followed up for between 3 to 10 months (mean 6.9 months). There were no reports of bowel incontinence or recurrence of fistula. The advantages of this 'tissue conserving' procedure are discussed in the paper.

Humans↗
PubMed1991

TAL2, a helix-loop-helix gene activated by the (7;9)(q34;q32) translocation in human T-cell leukemia.

Tumor-specific alteration of the TAL1 gene occurs in almost 25% of patients with T-cell acute lymphoblastic leukemia (T-ALL). We now report the identification of TAL2, a distinct gene that was isolated on the basis of its sequence homology with TAL1. The TAL2 gene is located 33 kilobase pairs from the chromosome 9 breakpoint of t(7;9)(q34;q32), a recurring translocation specifically associated with T-ALL. As a consequence of t(7;9)(q34;q32), TAL2 is juxtaposed with sequences from the T-cell receptor beta-chain gene on chromosome 7. TAL2 sequences are actively transcribed in SUP-T3, a T-ALL cell line that harbors the t(7;9)(q34;q32). The TAL2 gene product includes a helix-loop-helix protein dimerization and DNA binding domain that is especially homologous to those encoded by the TAL1 and LYL1 protooncogenes. Hence, TAL2, TAL1, and LYL1 constitute a discrete subgroup of helix-loop-helix proteins, each of which can potentially contribute to the development of T-ALL.

Amino Acid Sequence↗
PubMed1991

Amacrine cells in the tiger salamander retina: morphology, physiology, and neurotransmitter identification.

Amacrine cells of the vertebrate retina comprise multiple neurochemical types. Yet details of their electrophysiological and morphology properties as they relate to neurotransmitter content are limited. This issue of relating light responsiveness, dendritic projection, and neurotransmitter content has been addressed in the retinal slice preparation of the tiger salamander. Amacrine cells were whole-cell clamped and stained with Lucifer yellow (LY), then processed to determine their immunoreactivity (IR) to GABA, glycine, dopamine or tyrosine hydroxylase (TOH), and glucagon antisera. Widefield, ON-OFF amacrine cells were glycine-IR. The processes of these cells extended laterally in the inner plexiform layer (IPL) from 250-600 microns. They were either multistratified in the IPL or monostratified near the IPL midline. Three multistratified ON-OFF narrowfield glycine-IR cells also were found. Four types of ON amacrine cells were found to be GABA-IR; all types had their processes concentrated in the proximal IPL (sublamina b). Type I cells were narrowfield (approximately 100 microns) with a compact projection. Type II cells were widefield (220-300 microns) with a sparse projection. Type III cells had an asymmetrical projection and varicose processes. Type IV cells were pyriform and monostratified in sublamina b. One narrowfield ON-OFF amacrine cell, with processes broadly distributed in the middle of the IPL, was GABA-IR. This cell appeared similar to an ON-OFF cell that was glycine-IR and may comprise a type in which GABA and glycine colocalize. Another class of amacrine cell, with processes forming a major plexus along the distal border of the IPL and a lesser plexus in the proximal IPL, produced slow responses at light ON and OFF; these cells were dopamine/TOH-IR. A narrowfield class of transient ON-OFF amacrine cell, with processes ramifying throughout both sublaminae a and b of the IPL, were glucagon-IR; these cells appeared to be dye-coupled at the soma. We have shown that, with respect to GABA, glycine, dopamine, and glucagon, salamander amacrine cells fall into rather discrete groups on the basis of ramification patterns in the IPL and responses to photic stimulation. The physiological, structural, and neurochemical diversity of amacrine cells is indicative of multiple and complex roles in retinal processing.

Ambystoma↗
PubMed1991

Bacteremia in patients with cirrhosis of the liver.

Infections are frequent in patients with liver cirrhosis, as their defenses against infectious agents are altered. But bacteremia occurring in cirrhotic patients has seldom been reported in the literature. From 1981 to 1986, we collected 197 cases with 228 episodes of bacteremia for this retrospective study. The incidence of bacteremia in cirrhotic patients was 8.8%; no significant difference was noted between cirrhotic patients with variant etiologies of HBV(+), HBV(-) and alcohol. But the incidence increased with the severity of the disease (1%, 4.8%, 17.1% in Child's A, B, C groups, respectively). Gram-negative bacteria were the predominant microorganisms of bacteremia (75.6%). Among them, Escherichia coli, Klebsiella pneumoniae and Aeromonas hydrophilia were the three most commonly detected microorganisms. Gram-positive bacterias were detected in 21.2% of patients with bacteremia, with predominance of the Streptococcus group and Staphylococcus aureus. In about 26.3% of cases the infectious sources were the same by bacteria cultures as from blood. The most common sources were spontaneous bacterial peritonitis, urinary tract infection, pneumonia and biliary tree infection. In cirrhotic patients with and without bacteremia, the mortality rate increased significantly in the bacteremia group (54.8% vs 23.2%, P less than 0.05). By Child's classification, the mortality of patients with classes B and C increased significantly after onset of bacteremia. There was no significant difference in mortality between bacteremic patients in the HBV(+), HBV(-) and alcohol groups. In conclusion, bacteremia is a severe complication of liver cirrhosis and a sign of a poor prognosis.

Bacteremia↗
PubMed1991

[Quantification of acetabular coverage in normal adult].

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

Acetabulum↗