Search PubMed⌕ Search

Biomedical subjects

C T Wang

Publications and source records attributed to C T Wang.

At least 73 records · Page 4Linked to original sources
PubMed1993

Studies on the concentration of arsenic, selenium, copper, zinc and iron in the blood of blackfoot disease patients in different clinical stages.

Flame atomic absorption spectrophotometric methods were developed for the determination of zinc, copper, arsenic, iron and selenium in blood samples. Data from blackfoot disease patients in five clinical stages were compared with those from healthy controls. Copper concentrations were the same for all clinical stages. Arsenic increased in the initial three stages but decreased thereafter, although arsenic was previously considered to be the major causative agent of the disease. The decrease of arsenic in the later stages was attributed to the antagonistic effect of selenium, and the decrease of iron during the progress of the disease is thought to be due to the antagonistic effect of arsenic in the initial stages and the loose of haemoglobin in the later stages.

Aged↗
PubMed1992

Activation of human platelets by the rabbit anticardiolipin antibodies.

Affinity purified anticardiolipin antibodies (ACLA) raised in rabbits showed cross-reactivities with various negatively charged phospholipids as shown by both the solid phase enzyme-linked immunosorbent assay (ELISA) and inhibition studies. In ELISA, ACLA showed strong cross-reactivity to both sphingomyelin (SM) and phosphatidylethanolamine (PE), but the inhibition studies showed that ACLA failed to bind the aqueous suspensions of SM, PE, and PE/PC (1:1). ACLA bound to resting gel-filtered human platelets (GFP) as shown by both inhibition study and flow cytofluorometric analysis. Western blotting procedure showed that ACLA strongly cross-reacted to an 80-Kd plasma membrane protein. ACLA activated platelet response in a concentration-dependent manner. At less than 10 micrograms/mL, ACLA induced both platelet shape change to spiculate irregular forms as shown by scanning electron microscopy and the phosphorylation of 20-Kd protein. ACLA at more than 10 micrograms/mL caused platelet aggregation and secretion. The aggregation was inhibited by EDTA; aspirin; antimycin A plus 2-deoxyglucose; PGE1; and the F(ab')2 fragment of ACLA. It was not inhibited by monoclonal antibody to Fc receptor (MoAb FcR2). The biochemical events of ACLA-induced platelet response involved the elevation of (1) thromboxane A2 formation, (2) cytosolic free calcium ion concentration ([Ca2+]i), and (3) 47-Kd protein phosphorylation. In addition, the subaggregatory concentration of ACLA showed synergistic platelet activation with that concentration of thrombin, collagen, and epinephrine. The study showed the mechanism involved in ACLA-induced platelet responses.

Animals↗
PubMed1992

Retroviral envelope protein fusions to secreted and membrane markers.

We have analyzed a series of Moloney murine leukemia (M-MuLV) envelope (env) protein fusions to the marker proteins invertase and placental alkaline phosphatase (PLAP), expressed in Psi2 retrovirus packaging cells. The yeast invertase protein, fused at its third amino acid residue to the amino-terminal signal sequence and 17 residues of the mature M-MuLV env protein, retained its enzymatic activity and was secreted from mammalian cells. However, env protein fusions to the C-terminal portion of invertase were inactive. In contrast, some, but not all, env protein fusions at the C-terminal region of PLAP were enzymatically active: PLAP fusions containing long C-terminal portions of env localized to the rough endoplasmic reticulum (RER) and possessed low enzyme activity levels, while fusion constructs containing relatively short portions of the M-MuLV env gene localized to the Golgi and had higher activity levels. Those proteins that localized to the Golgi also were processed, in part, to forms of 67 to 68 kDa, the size of the mature PLAP protein. Since PLAP ordinarily is transferred to a phosphatidyl-inositol glycan tail (PIG-tail) in the Golgi and then transported to the plasma membrane, it appears that Golgi-localized PLAP-env fusions are processed imperfectly. PLAP itself, when expressed in Psi2 cells, accumulated at the plasma membrane and, unlike the PIG-tailed Thy-1 protein, was not incorporated into virus particles. Thus, the reported incorporation of the Thy-1 protein into M-MuLV virions does not appear to be a consequence of its glycoprotein tail.

Alkaline Phosphatase↗
PubMed1992

Congenital absence of the pulmonary valve: report of two cases with review of the literature.

Congenital absence of the pulmonary valve is an uncommon combination of anomalies. Recently, we encountered two such cases, one associated with tetralogy of Fallot (case 1), the other with ventricular septal defect (case 2). Clinically, our cases had minimum symptoms. The congenital cardiac anomalies were diagnosed with physical examination, chest x-ray film, echocardiography, and confirmed with cineangiography. These procedures disclosed a rudimentary pulmonary valve, pulmonary regurgitation and aneurysmal dilatation of the main and right pulmonary artery. In case 2, the right lower pulmonary artery occlusion and left hydronephrosis were also demonstrated by magnetic resonance imaging. The two cases underwent surgical repair to correct the tetralogy of Fallot and the ventricular septal defect respectively. Our experience in diagnosing these cardiac anomalies is reported.

Child↗
PubMed1992

Topical application of local anesthetics for postoperative analgesia in children undergoing circumcision.

Circumcision often followed by severe pain during the postoperative period. Forty boys, ASA class I, presenting for day case circumcision were allocated randomly to receive either 4% prilocaine hydrochloride spray or 1.1% dipucaine ointment at the end of the operation. Analgesia was assessed by a single observer utilizing a three-point scale in recovery room. The parents were asked to complete the questionnaire 8h following operation and on the morning of the first postoperative day. At approximately 24h following operation an assessment of the child's activity level was made by the parents. The frequency of taking the oral analgesia was also recorded. Both topical analgesics provided satisfied analgesia during the postoperative period and no complication was noted. Only one patient in dipucaine group vomited in the recovery room. We conclude that topical use of prilocaine hydrochloride and dipucaine can provide a simple, safe and adequate analgesia for post-circumcision pain relief.

Administration, Topical↗
PubMed1991

The inhibition of human platelet function by ganodermic acids.

Human gel-filtered platelets aggregate at greater than 20 microM-ganodermic acid S [lanosta-7,9(11),24-triene-3 beta, 15 alpha-diacetoxy-26-oic acid] [Wang, Chen, Shiao & Wang (1989) Biochim. Biophys. Acta 986, 151-160]. This study showed that platelets at less than 20 microM-ganodermic acid S displayed both concentration- and time-dependent inhibition of function, in which the agent potency in response to inducers was ADP-fibrinogen greater than collagen greater than thrombin. The agent caused a biphasic time-dependent effect on platelet phosphoinositide metabolism. The first phase involved the decrease in the pool size of phosphoinositide by 10-20%. The second phase, in which both the resynthesis of phosphatidylinositol 4,5-bisphosphate (PIP2) and the decrease of [32P]phosphatidic acid occurred, took place after 30 min. Scanning electron microscopy also revealed a time-dependent morphological change in platelets in the presence of the agent. The cells initially became spiculate discs, then swelled to a 'potato-like' morphology at 60 min. Further studies on the time-dependent inhibition of thrombin response revealed that: (1) the percentage inhibition of cell aggregation was comparable with that occurring with an increase of cytosolic free Ca2+ concentration [( Ca2+]i) or the phosphorylation of marker proteins; (2) [32P]Pi-labelled platelets showed the time-dependent inhibition of thrombin-stimulated PIP2 resynthesis as indicated by first-2-min time-course studies of phosphoinositide interconversion; (3) scanning electron microscopy revealed that the aged platelet population showed an increase in the percentage of non-responding cells on prolonged incubation. The results, taken together, enabled one to discuss a possible mechanism for the time-dependent inhibition by ganodermic acid S of platelet response to thrombin.

Blood Platelets↗
PubMed1991

Cellular transcripts encoded at a locus which permits retrovirus expression in mouse embryonic cells.

Three independent recombinant retroviruses have been activated on insertion into the F2 locus of mouse F9 embryonal carcinoma cells. Each provirus has integrated downstream from the cellular F2 promoter, which is active in transient transfection assays using a chloramphenicol acetyltransferase reporter enzyme. The F2 promoter drives expression of a series of related transcripts in F9 and 3T3 cells, and a single 450-nt transcript in mouse tissues. F2 homologous sequences have been detected in the genomes of all mammalian species tested, and the 450-nucleotide (nt) F2 transcript is expressed in rat and human cells. Three pairs of differently sized F2 cDNA clones have been isolated and analyzed. The largest clones possess two 199-nt 98.5% identical repeats, one of which is present in the smaller clones, as well as the major 450-nt transcript. Activated proviral integration sites map to introns of the largest F2 cDNA clone. While none of the F2 cDNA contains a long open reading frame or homology to databank sequences, evidence suggests that the F2 locus encodes a constitutive function required at high levels, or represents an expressed but nonfunctional, single-copy element, conserved among mammals.

Animals↗
PubMed1991

Bovine leukemia virus infection in Taiwan: epidemiological study.

We conducted a seroepidemiological survey for antibodies to bovine leukemia virus (BLV), by using agar gel immunodiffusion technique, in dairy cows, water buffaloes, and yellow cattle throughout Taiwan. The positive reactors were 8.4% (376/4,459) in 1985 and 5.8% (1,277/22,190) in 1986, in 15 prefectures and 7 cities. Relatively high infection rate appeared in the northern and southern areas of Taiwan. Positive reactors increased gradually with age. The incidence of positive antibodies was 2 to 3 times higher in pasture-style farms than in housed-style farms. Among the 6,313 imported cattle, 302 (4.8%) showed positive reaction. Between 1985 and 1987, 5 cattle showed enzootic bovine leukosis among 351 sero-positive reactors in four highly positive prefectures. Survey of 134 water buffaloes and yellow cattle showed no positive reactors. This survey demonstrated that BLV-infection has increased over the years and spread throughout Taiwan.

Animals↗
PubMed1991

A deterministic computer simulation model of life-cycle lamb and wool production.

A deterministic mathematical computer model was developed to simulate effects on life-cycle efficiency of lamb and wool production from genetic improvement of performance traits under alternative management systems. Genetic input parameters can be varied for age at puberty, length of anestrus, fertility, precocity of fertility, number born, milk yield, mortality, growth rate, body fat, and wool growth. Management options include mating systems, lambing intervals, feeding levels, creep feeding, weaning age, marketing age or weight, and culling policy. Simulated growth of animals is linear from birth to inflection point, then slows asymptotically to specified mature empty BW and fat content when nutrition is not limiting. The ME intake requirement to maintain normal condition is calculated daily or weekly for maintenance, protein and fat deposition, wool growth, gestation, and lactation. Simulated feed intake is the minimum of availability, DM physical limit, or ME physiological limit. Tissue catabolism occurs when intake is below the requirement for essential functions. Mortality increases when BW is depressed. Equations developed for calculations of biological functions were validated with published and unpublished experimental data. Lifetime totals are accumulated for TDN, DM, and protein intake and for market lamb equivalent output values of empty body or carcass lean and wool from both lambs and ewes. These measures of efficiency for combinations of genetic, management, and marketing variables can provide the relative economic weighting of traits needed to derive optimal criteria for genetic selection among and within breeds under defined industry production systems.

Animals↗
PubMed1991

Simulation of life-cycle efficiency of lamb and wool production for genetic levels of component traits and alternative management options.

A deterministic computer model was used to predict effects of genetic improvements in performance and of management options on life-cycle flock TDN input per unit of empty body weight (EBW) or carcass lean (CLN) equivalent value of market lamb, cull ewe, and wool output from a pure breeding system of sheep production for sheep fed to maintain normal weight. Relative values per kilogram for market lambs, cull ewes, and clean wool were 1 to .33 to 2.04 in lamb empty body equivalent, but 1 to .33 to 1 in lamb carcass lean equivalent. A 10% increase in lamb viability improved TDN/EBW or CLN by -15 to -20% for high to low lambing rates. Corresponding smaller gains were -7 to -11% for fertility, -3 to -13% for lambing rate, -1 to -3% for wool growth rate, -1 to -5% for milk production without creep feeding, -2 to -1% for mature size to about 70 kg, and -.6 to -.9% for precocity of fertility. Increasing leanness 10% improved TDN/CLN by -3 to -1% but increased TDN/EBW 3% because of higher maintenance requirements of leaner sheep. Higher protein requirements for increased lambing rate, milk production or leanness, or greater increases in non-feed than in feed costs, would mean only slightly less reduction of TDN/output than shown. Creep feeding was beneficial only for prolific, low-milking stock. Flushing reduced adverse effects of restricted feeding. Different values for wool vs meat or for costs of feed vs non-feed inputs would change results. These estimates for relative economic importance of traits apply to derivation of optimum criteria for selection among breeds or crosses, or within-breeds used in rotation crossbreeding, but would differ for specialized terminal-sire or maternal breed roles.

Animal Husbandry↗
PubMed1991

Simulated effects of reproductive performance on life-cycle efficiency of lamb and wool production at three lambing intervals.

A deterministic computer model of a purebreeding sheep production system was used to simulate effects on life-cycle efficiency from genetic changes in lambing rate (LB), fertility (FERT), precocity of fertility (PREC), and estrus season length (ES) under annual (Y), 4-mo (A), and 73-d (S) breeding intervals. Ewes and lambs of a 1,000-ewe flock were fed to requirement through five yr, beginning with ewe lambs at the optimal breeding season and accumulating feed input (TDN) and market lamb equivalent weight of output (EBW), including cull ewes and wool. For annual lambing, improvement in cost (TDN/EBW equivalence) per 10% increase in genetic potential was -9.8, -8.2, -1.3, and -.8% for LB, FERT, PREC, and ES, respectively. For the A and S lambing intervals, corresponding gains in TDN efficiency were -19 for FERT and -9% for LB when ES was 72 d, but only -6 and -5% when ES was 192 d. Increasing PREC by 10% improved cost -3% under accelerated systems when ES was 72 d, but less than -1% when ES was 192 d. Cost reduction from 10% longer ES under A and S breeding intervals was greater when other reproductive performance was low (-11 and -17%) rather than high (-2 and -3%). Reduction in costs for A and S vs Y lambing intervals was greatest with long ES and was greater with low (-43 and -53%) than with high reproductive performance (-20 and -24%). When ES was 72 d, A and S intervals would reduce costs for high (-9 and -11%) but increase costs for low reproductive traits. Corresponding increases in CP/TDN required in diet would reduce gains in TDN/EBW only slightly. These results should aid in development of optimum selection criteria for stocks used for pure or rotation crossbreeding or as maternal parents of terminal crosses.

Animal Husbandry↗
PubMed1991

Bovine leukemia virus infection in Taiwan: evaluation of the enzyme-linked immunosorbent assay and agar gel immunodiffusion test.

I evaluated an enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion (AGID) test simultaneously for the detection of bovine leukemia virus (BLV) antibodies. Total 1,293 serum samples were tested for ELISA and AGID test and the results were compared. The results of ELISA and AGID agreed by 1,156 out of 1,293 (89.4%). All of AGID-positive 356 sera were positive by ELISA. However, of 451 ELISA-positive sera, 95 sera were either negative or equivocal by AGID test. Eleven animals which showed ELISA-positive but AGID-negative or equivocal became AGID-positive in a year. It may be inferred that ELISA detects infected cattle earlier and with greater sensitivity than AGID.

Animals↗
PubMed1991

[Influences of open thoracoscopy on human body: experience in 65 cases].

The influence of open thoracoscopy with fiber-bronchoscope on human body was studied in 65 patients with pleural disease. The items observed included blood pressure, Pulse rate, respiration rate, blood gas analysis and clinical manifestations. It was found that open thoracoscopy has little influence on human body and the patients tolerated it well. No severe complication was found and operative procedures might be avoided popularization of this technique is therefore suggested.

Adolescent↗
PubMed1990

The effect of ganodermic acid S on human platelets.

Incubation of gel-filtered human platelets in ganodermic acid S (lanosta-7,9(11), 24-trien-3 beta, 15 alpha-diacetoxy-26-oic acid) showed that uptake of the agent by platelets was a simple diffusion process. The agent caused platelet aggregation at concentrations above 20 microM. Above the threshold, the extent of cell aggregation was in a linear relationship to the agent concentration. Below the aggregation threshold, platelets showed neither the resynthesis of [32P] phosphatidylinositol 4,5-bisphosphate ([32P]PIP2) and [32P] phosphatidylinositol 4-phosphate ([32P]PIP) nor the accumulation of [32P] phosphatidic acid ([32P]PA). The results suggested that ganodermic acid S caused the activation of PIP2 hydrolysis. Scanning electron microscopy revealed that the morphology of platelets below the aggregation threshold appeared to be spiculate discoid shape. Above the threshold, the cells rounded up to spiculate irregular forms.

Biological Transport↗
PubMed1989

The aggregation of human platelet induced by ganodermic acid S.

Incubation of gel-filtered human platelets in ganodermic acid S (lanosta-7,9(11),24-trien-3 beta,15 alpha-diacetoxy-26-oic acid) showed that within a min 80% of the agent was taken up by the cells. The process of uptake was a simple diffusion, and the partition coefficient was about 10(5). The agent caused platelet aggregation at a concentration above 20 microM. Above the threshold, the extent of cell aggregation was in a linear relationship to the agent concentration. Also, the % of cell aggregation was comparable to the elevation of: (1) cytosolic free Ca2+ concentration [( Ca2+]i); (2) protein phosphorylation; and (3) serotonin release. Also, it was correlated with the change in the interconversion of phosphoinositides. Moreover, platelets in various concentrations of ganodermic acid S appeared to show different time-course profiles in the changes of [32P]phosphoinositides and [32P]phosphatidic acid (PA). Upon addition of the agent, platelets showed an initial increase in all of the [32P]phosphoinositides, and then the level of each kind of phosphoinositide decreased sequentially in phosphatidylinositol 4,5-bisphosphate (PIP2), phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol (PI). Below the aggregation threshold, platelets showed neither the resynthesis of [32P]PIP2 and [32P]PIP nor the accumulation of [32P]PA. However, at 25 and 50 microM, platelets showed not only the resynthesis of [32P]PIP2 and [32P]PIP but also the accumulation of [32P]PA. Interestingly, at 100 microM ganodermic acid S, platelets did not show the resynthesis of [32P]PIP2 and [32P]PIP. In this case, the level of [32P]PA accumulation and that of [32P]PI decrease were less than those found in platelets at 50 microM ganodermic acid S. The results suggested that ganodermic acid S caused the activation of PIP2 hydrolysis. Scanning electron microscopy (scanning EM) revealed that the morphology of platelets below the aggregation threshold appeared to be spiculate discoid shape. Above the threshold, the cells rounded up to spiculate irregular forms, which showed an elongation of filopodia after prolonged 30-s incubation. In addition, platelets at greater than or equal to 50 microM ganodermic acid S showed the occurrence of membrane vesiculation. Hence, the incorporation of ganodermic acid S into platelet membrane resulted in the change of membrane morphology.

Biological Transport↗
PubMed1989

The solubilization and morphological change of human platelets in various detergents.

The solubilization of human gel-filtered platelets by octyl glucoside, Triton X-100, dodecylsulfate, and deoxycholate was compared from the analysis of (1) cell lysis, (2) marker leakiness, and (3) component solubility. These analyses all revealed that the effect of detergent concentration on the solubilization of platelets by these detergents was exerted in three stages, i.e., the prelytic, lytic, and complete platelet-lysis stages. These analyses also indicated several differences among platelets in these detergents. (i) The ratio of the platelet-saturation concentration (PSC) to critical micellar concentration (CMC) was about 1/2 for octyl glucoside. Triton X-100 and dodecylsulfate, while it was close to 1 for deoxycholate. (ii) Platelets in octyl glucoside. Triton X-100, and dodecylsulfate all showed parallel curves in cell lysis, protein solubilization and marker leakiness, while the platelet lysis in deoxycholate was identical to the phospholipid solubilization. (iii) The solubility curves of various components in Triton X-100 and deoxycholate were parallel. However, the solubility of cholesterol in octyl glucoside was lower than that of protein and phospholipid. In dodecylsulfate, the solubility of phospholipid and cholesterol was very low in comparison with that of protein. In addition, morphological studies using scanning electron microscopy (scanning EM) revealed that the solubilization by octyl glucoside or Triton X-100 might occur via membrane area expansion. On the other hand, the solubilization by dodecylsulfate or deoxycholate showed membrane vesiculation prior to cell lysis. Moreover, in the prelytic stage, the morphological change in platelets in octyl glucoside showed only concentration dependence by swelling to an ellipsoid and then to a sphere. However, the morphological change in platelets in the other three detergents was dependent not only on the detergent concentration but also on prolonged incubation. Specifically, in Triton X-100, the cells initially changed to spiculate discs and then reached their final shape as swollen discs with surface invagination. In dodecylsulfate and deoxycholate the morphological changes were almost the same. The cell initially deformed in shape to a spiculate disc and finally to a stretched-out flat form. The results are discussed according to the bilayer couple hypothesis. Also, in the prelytic stage, these detergents caused inhibition of the response of platelets to collagen and ADP-fibrinogen.

Blood Platelets↗