Biomedical subjects

C C Wang

Publications and source records attributed to C C Wang.

At least 91 records · Page 5Linked to original sources

PubMed2001

Infection of mice with the helminth Strongyloides stercoralis suppresses pulmonary allergic responses to ovalbumin.

Asthma and helminth infections induce similar immune responses characterized by the presence of peripheral blood eosinophilia and elevated serum IgE levels. Epidemiological surveys have reported either increases or decreases in the development of atopic diseases and asthma based on the prevalence of helminth infections in the population. The aim of this study was to determine if a pre-existing helminth infection would increase or decrease subsequent allergic responses to an unrelated allergen in the lungs. BALB/cByJ mice were infected with the nematode parasite Strongyloides stercoralis prior to ovalbumin (OVA) immunization and intratracheal challenge. Bronchoalveolar lavage (BAL) and fluid (BALF) were collected 3 days post-challenge and cellular and humoral immune responses were measured. Intracellular cytokine staining revealed increased IL-4 and IL-5 producing cells in BAL from mice infected with S. stercoralis before OVA sensitization. Increased IL-5 protein levels and decreased IFN-gamma protein levels were also observed in the BALF. There was, however, no increase in airway eosinophil accumulation in mice infectd with parasites before sensitization with OVA as compared to mice exposed to OVA alone. Furthermore, eotaxin levels in the lungs induced by OVA was suppressed in mice infected with the parasite before OVA sensitization. The development of OVA specific IgE responses in BALF was also impaired in mice infected with the parasite before sensitization with OVA. These results suggest that a pre-existing helminth infection may potentiate a systemic Type 2-type response yet simultaneously suppress in the lungs allergen-specific IgE responses and eotaxin levels in response to subsequent exposure to allergens.

Allergens↗

PubMed2001

Thermodynamics of the folding of D-glyceraldehyde-3-phosphate dehydrogenase assisted by protein disulfide isomerase studied by microcalorimetry.

Thermodynamics of the refolding of denatured D-glyceraldehyde 3-phosphate dehydrogenase (GAPDH) assisted by protein disulfide isomerase (PDI), a molecular chaperone, has been studied by isothermal microcalorimetry at different molar ratios of PDI/GAPDH and temperatures using two thermodynamic models proposed for chaperone-substrate binding and chaperone-assisted substrate folding, respectively. The binding of GAPDH folding intermediates to PDI is driven by a large favorable enthalpy decrease with a large unfavorable entropy reduction, and shows strong enthalpy-entropy compensation and weak temperature dependence of Gibbs free energy change. A large negative heat-capacity change of the binding, -156 kJ.mol(-1).K(-1), at all temperatures examined indicates that hydrophobic interaction is a major force for the binding. The binding stoichiometry shows one dimeric GAPDH intermediate per PDI monomer. The refolding of GAPDH assisted by PDI is a largely exothermic reaction at 15.0-25.0 degrees C. With increasing temperature from 15.0 to 37.0 degrees C, the PDI-assisted reactivation yield of denatured GAPDH upon dilution decreases. At 37.0 degrees C, the spontaneous reactivation, PDI-assisted reactivation and intrinsic molar enthalpy change during the PDI-assisted refolding of GAPDH are not detected.

Animals↗

PubMed2001

Induction of dental pulp fibroblast matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 gene expression by interleukin-1alpha and tumor necrosis factor-alpha through a prostaglandin-dependent pathway.

Matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) are involved in the degradation of extracellular matrix in many inflammatory diseases. Little is known regarding the expression of these mediators in dental pulp fibroblasts. The effects of proinflammatory cytokines (interleukin (IL)-1alpha and tumor necrosis factor-alpha (TNF-alpha)) and prostaglandin E2 (PGE2) on pulp fibroblast MMP-1 and TIMP-1 gene expression were investigated. Northern hybridization showed that IL-1alpha and TNF-alpha induced significant MMP-1 gene expression, with only little effect on TIMP-1 gene. Exogenous PGE2, however, upregulated TIMP-1 mRNA synthesis but not MMP-1. Concomitant addition of IL-1alpha and PGE2 or TNF-alpha and PGE2 suppressed MMP-1 mRNA production, compared with the groups treated with IL-1alpha or TNF-alpha alone. In contrast, PGE2 enhanced the upregulatory effects of TIMP-1 mRNA by IL-1alpha or TNF-alpha. Furthermore, cytokine stimulation of MMP-1 and TIMP-1 gene expressions can be enhanced or blocked by indomethacin, respectively, and reversed by exogenous PGE2. These results suggested that cytokine-stimulated MMP-1 and TIMP-1 gene expression in dental pulp fibroblasts was mediated, at least in part, by a prostaglandin-dependent pathway. The differential regulation of IL-1alpha or TNF-alpha-induced MMP-1 and TIMP-1 mRNA synthesis, as well as the direct upregulation of TIMP-1 gene expression by PGE2, also implied that prostaglandin may serve as a protective mechanism from excessive tissue breakdown during pulpitis.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

Oxidative stress in the fetal lamb brain following intermittent umbilical cord occlusion: a path analysis.

OBJECTIVE: To evaluate the relative contribution of cord occlusion length intervals between occlusions and experimental duration on oxidative stress in the fetal lamb brain. DESIGN: Acute, partially exteriorised fetal lambs with intermittent total cord occlusion. SETTING: The Vivarium of Westmead Hospital, University of Sydney, Australia and The Chinese University of Hong Kong. MAIN OUTCOME MEASURES: Arterio-venous differences in the concentration of organic hydroperoxides, measured in paired samples of carotid arterial and jugular venous blood, as an index of oxidative stress in the brain. METHODS: Thirty-two fetal lambs were exposed to graded hypoxia, induced by intermittent total umbilical cord compression of 30 seconds, 60 seconds and 90 seconds duration, occurring every minute for a total of 27 occlusions over 81 minutes. Three sham experiments were also performed. In addition to organic hydroperoxides, carotid arterial blood samples were also assayed in 15 animals (two sham) for oxygen saturation, pH, hypoxanthine, xanthine and urate concentrations. A causal model for oxidative stress was defined: occlusions leading to hypoxia with a rise in hypoxanthine; reperfusion during intervals between occlusions leading to the accelerated production of xanthine and uric acid and the generation of oxygen free radicals, which in turn, are responsible for the rise in lipid peroxidation. Path analysis was performed to assess the strength of the relationships between these variables and the cord occlusion length, the interval between occlusions and the duration of the experiment. RESULTS: Sham experiments showed no change in organic hydroperoxide production. Following 30-second umbilical cord occlusions a sixfold drop in mean organic hydroperoxides was observed between carotid arterial and jugular venous levels. In contrast, following occlusions of 60 seconds duration (or longer) a median 20-fold increase in organic hydroperoxide production was observed. Path analysis revealed a strong indirect pathway from occlusion length --> hypoxanthine --> urate and weak positive pathways from oxygen saturation --> urate and from interval between occlusions --> urate. After accounting for these pathways reflecting oxidative stress, a strong direct path remained from time from first occlusion --> organic hydroperoxide production. CONCLUSIONS: Peroxidation of lipids in the brain occurs under conditions of severe hypoxia and reperfusion associated with intermittent umbilical cord occlusions of 60 seconds or longer. The path analysis supported the causal model as originally defined, with the exception that the indirect pathway via pH was found to be trivial.

Animals↗

PubMed2001

Virtual screening of combinatorial libraries across a gene family: in search of inhibitors of Giardia lamblia guanine phosphoribosyltransferase.

Parasitic protozoa lack the ability to synthesize purine nucleotides de novo, relying instead on purine salvage enzymes for their survival. Guanine phosphoribosyltransferase (GPRT) from the protozoan parasite Giardia lamblia is a potential target for rational antiparasitic drug design, based on the experimental evidence, which indicates the lack of interconversion between adenine and guanine nucleotide pools. The present study is a continuation of our efforts to use three-dimensional structures of parasitic phosphoribosyltransferases (PRTs) to design novel antiparasitic agents. Two micromolar phthalimide-based GPRT inhibitors were identified by screening the in-house phthalimide library. A combination of structure-based scaffold selection using virtual library screening across the PRT gene family and solid phase library synthesis led to identification of smaller (molecular weight, <300) ligands with moderate to low specificity for GPRT; the best inhibitors, GP3 and GP5, had K(i) values in the 23 to 25 microM range. These results represent significant progress toward the goal of designing potent inhibitors of purine salvage in Giardia parasites. As a second step in this process, altering the phthalimide moiety to optimize interactions in the guanine-binding pocket of GPRT is expected to lead to compounds with promising activity against G. lamblia PRT.

Animals↗

PubMed2001

Structural analysis of the -1 ribosomal frameshift elements in giardiavirus mRNA.

The RNA polymerase of giardiavirus (GLV) is synthesized as a fusion protein through a -1 ribosomal frameshift in a region where gag and pol open reading frames (ORFs) overlap. A heptamer, CCCUUUA, and a potential pseudoknot found in the overlap were predicted to be required for the frameshift. A 68-nucleotide (nt) cDNA fragment containing these elements was inserted between the GLV 5' 631-nt cDNA and the out-of-frame luciferase gene that required a -1 frameshift within the 68-nt fragment for expression. Giardia lamblia trophozoites transfected with the transcript of this construct showed a frameshift frequency at 1.7%, coinciding with the polymerase-to-capsid protein ratio in GLV. The heptamer is required for the frameshift but can be replaced with other sequences of the same motif. Mutations placing stop codons in the 0 or -1 frame, located directly before or after the heptamer, implicated the latter as the site for the -1 frameshift. Shortening or destroying the putative stem decreased the frameshift efficiency threefold; the efficiency was fully recovered by mutations to restore the stem. Deleting 18 nt from the 3' end of the 68-nt fragment, which formed the second stem in the putative pseudoknot, had no effect on the frequency of the frameshift. Chemical probing of the RNA secondary structure in the frameshift region showed that bases resistant to chemical modification were clustered in the putative stem structures, thus confirming the presence of the postulated stem-loop, while all the bases in the loop were chemically modified, thus ruling out their capability of forming a pseudoknot. These results confirmed the conclusion based on data from the mutation study that there is but a simple stem-loop downstream from the heptamer. Together, they constitute the structural elements for a -1 ribosomal frameshift in the GLV transcript.

Giardiavirus↗

PubMed2001

Matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 gene expressions and their differential regulation by proinflammatory cytokines and prostaglandin in nasal polyp fibroblasts.

Chronic inflammation of the paranasal sinus leads to nasal polyp (NP) formation. In this study, we investigated the effect of stimulation of the proinflammatory cytokines interleukin-1alpha (IL-1alpha) and tumor necrosis factor-alpha (TNF-alpha) and prostaglandin (PG) E2 on the production of messenger RNA (mRNA) of matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-I (TIMP-1) in nasal polyp fibroblasts (NPFs) and nasal mucosa fibroblasts (NFs). The mRNAs of IL-1alpha, TNF-alpha, MMP-1, and TIMP-1 in 40 surgical specimens of NPs were studied by in situ hybridization to corroborate the in vitro findings. The results indicated a significant amount of constitutive MMP-1 mRNA in NPFs and cytokine-induced MMP-1 steady-state mRNAs in NFs. The effect of stimulation of cytokines on TIMP-1 mRNA synthesis was unremarkable in NPFs and NFs. Exogenous PGE2 enhanced cytokine-stimulated MMP-1 mRNA synthesis in NPFs. In situ hybridization revealed that cells expressing MMP-1 and TIMP-1 mRNAs (primarily plasma cells, fibroblasts, and endothelial cells) gathered around areas with loose stroma, suggestive of rapid extracellular matrix degradation. These data suggest that the pathogenesis of nasal polyposis could be related to production of MMP-1 and consequent promotion of matrix collagenolysis.

Cytokines↗

PubMed2001

Photovoice ethics: perspectives from Flint Photovoice.

Photovoice is a participatory health promotion strategy in which people use cameras to document their health and work realities. As participants engage in a group process of critical reflection, they may advocate for change in their communities by using the power of their images and stories to communicate with policy makers. In public health initiatives from China to California, community people have used photovoice to carry out participatory needs assessment, conduct participatory evaluation, and reach policy makers to improve community health. This article begins to address ethical issues raised by the use of photovoice: the potential for invasion of privacy and how that may be prevented; issues in recruitment, representation, participation, and advocacy; and specific methodological techniques that should be used to minimize participants' risks and to maximize benefits. The authors describe lessons learned from the large-scale Flint Photovoice involving youth, adults, and policy makers.

Commerce↗

PubMed2001

Biliary complications in living related liver transplantation.

BACKGROUND: Biliary tract reconstruction has long been considered the Achilles' heel of liver transplantation as biliary complications can increase morbidity and mortality especially in partial liver graft transplantation. METHODS: Thirty-four living related liver transplants were performed at Chang Gung Memorial Hospital in Kaohsiung for 33 children and 1 adolescent during a 5.5-year period. All potential donors underwent a detailed preoperative imaging study of the vascular and biliary anatomy, including three-dimensional helical computed tomographic cholangiography (n = 20), magnetic resonance cholangiography (n = 14), and intra-operative cholangiography (n = 31) before graft retrieval. All hepatic artery anastomoses were performed in the standard microsurgery fashion and their patency was confirmed intra-operatively using Doppler ultrasound. RESULTS: The biliary complication rate was 8.8% (3/34), including multiple intrahepatic biliary stenosis of unknown origin (n = 1), bile leakage from the Roux-en-Y loop (n = 1), and a missed biliary radicle (n = 1) which were treated via interventional radiological and surgical procedures. The overall graft and patient survival rates were 100%. CONCLUSION: The biliary complication rate in this series was low compared to those of other experienced centers. Complete study of the variations of intrahepatic duct ramification pre-and-intra-operatively provided adequate information on the appropriate transection plane. Furthermore, intra-operative Doppler ultrasound verification of vessel patency helps prevent vascular complications, which has been identified as a cause of biliary complications.

Adolescent↗

PubMed2001

Acrylonitrile removal from synthetic wastewater and actual industrial wastewater with high strength nitrogen using a pure bacteria culture.

A gram-negative rod-shaped bacteria (strain AAS6), capable of utilizing acrylonitrile as the sole source of both carbon and nitrogen, was utilized to investigate the removal of acrylonitrile in ABS resin manufacturing wastewater. Both synthetic wastewater, containing a high concentration of acrylonitrile, and actual wastewater obtained from an ABS manufacturing factory were used. The result indicated that strain AAS6 was capable of completely removing acrylonitrile from synthetic wastewater containing less than 889 mg/l acrylonitrile and from actual industrial wastewater containing less than 400 mg/l acrylonitrile. Whether in synthetic wastewater or actual industrial wastewater, strain AAS6 showed approximately the same ability for acrylonitrile removal and used acrylic acid, a metabolic by-product of acrylonitrile, as the carbon source and ammonium as the nitrogen source. The bacteria could not directly metabolize other chemicals found in the actual industrial wastewater. However, its metabolic activities were not inhibited by the presence of compounds such as butadiene, styrene or acrylonitrile-styrene polymer. Thus, this strain is expected to play an important role in aeration tanks for treating ABS resin manufacturing wastewater.

Acrylonitrile↗

PubMed2001

Chronic granulomatous disease: a case report.

Chronic granulomatous disease is one form of the phagocyte function disorder. Unlike most patients with chronic granulomatous disease who develop signs and symptoms of chronic and recurrent pyogenic infections during the first 2 years of life, patients with mild forms of the disease may not present until the teenage years or even adulthood. Thus, the diagnosis in these mild-form patients is often delayed. This paper describes a patient with the mild form of chronic granulomatous disease. A 7-year-old boy was admitted to our ward with intermittent high fever and a left neck mass present for about 1 week. He had a history of persistent infection in the bilateral lower face lasting for about 1 year during his fourth year of life. Family history was unremarkable except that the patient's elder sister had a history of persistent oral mucosal wound infection for about 1 year during the fifth year of life. On physical examination, there were scars over the patient's bilateral lower face. Bacterial culture of pus drained from the neck mass revealed Burkholderia cepacia, a rare species in patients without immunodeficiency. A series of antibiotics, including oxacillin, clindamycin, and piperacillin, was given, and two incision operations for drainage and debridement were performed. The neck mass resolved completely about 1.5 months later. This history indicated that the patient might have chronic granulomatous disease. A definite absence of superoxide activity in the patient's granulocytes detected by chemiluminescence and nitroblue tetrazolium dye test confirmed this diagnosis.

Child↗

PubMed2001

Diagnosis and treatment of lipomas of the internal auditory canal.

A Chinese woman came to the otolaryngology department with a complaint of a longstanding progressive left hearing loss and intractable tinnitus. A finding of asymmetry on sensorineural hearing loss and auditory brainstem response testing provided evidence of a retrocochlear lesion on the left side. Computed tomography and magnetic resonance imaging detected a tumor in the left internal auditory canal (IAC). In addition to these radiologic features, our suspicion of the possibility of an IAC lipoma was raised by the observation of multiple lipomas over the patient's trunk and limbs. The patient underwent a complete tumor resection via the translabyrinthine approach, Pathology confirmed the diagnosis of an IAC lipoma. Although we were not able to preserve the hearing in her left ear, the patient was satisfied that we had relieved her constant tinnitus. In this article, we review the particulars of this case and discuss the clinical, radiologic, and pathologic features of IAC lipomas.

Adult↗

PubMed2001

Meningitis due to penicillin-resistant Neisseria meningitidis in a 20-year-old man.

The emergence of meningococcal strains with reduced susceptibility to penicillin has been reported in several countries during the past two decades, but not in Taiwan. We report a case of meningococcal meningitis with intermediate resistance to penicillin. A 20-year-old male soldier complained of chills, fever, and headache for 2 days, followed by drowsiness. Physical examination revealed erythema of the pharynx, stiff neck, erythematous maculopapules, and petechiae over the trunk and four limbs including palms and soles. Analysis of the cerebrospinal fluid (CSF) showed a white blood cell count of 9.06 x 10(6)/L, a glucose concentration of 0.165 mmol/L, and a protein concentration of 7.85 g/L. CSF culture yielded Neisseria meningitidis, serogroup B. The minimum inhibitory concentration of penicillin was determined using an E-test (0.125 microgram/mL); there was no beta-lactamase production. He recovered after high-dose penicillin G treatment with six doses of 24 million units per day for 11 days. The emergence of penicillin resistance in N. meningitidis in Taiwan requires surveillance. High-dose penicillin may be successful in treating penicillin-insensitive meningococcal meningitis. Alternative treatment with third-generation cephalosporins should be considered if poor response to penicillin is encountered.

Adult↗

PubMed2001

Acute myocardial infarction caused by aortic dissection.

Clinical presentation of aortic dissection is similar to that of acute myocardial infarction (AMI). Clinical differential diagnoses from lethal chest pain in emergency department include AMI, aortic dissection, pulmonary embolism, tension pneumothorax, etc. Thrombolytic therapy for recanalization of thrombotic occluded coronary artery in AMI must be considered, but it is absolutely contraindicated for aortic dissection. However, AMI secondary to aortic dissection is a rare condition, which might be caused by compression of the coronary arteries by a hematoma or extension of the dissection into the coronary arterial wall. Surgery is the first choice for AMI secondary to aortic dissection caused by extension of dissection into the coronary arterial wall. We present a case of inferior wall AMI caused by type I aortic dissection with presentation of chest pain and hemiparaplegia of right lower limb.

Aortic Diseases↗

PubMed2001

Perinatal cytomegalovirus infection complicated with pneumonitis and adrenalitis in a premature infant.

Cytomegalovirus causes pneumonia, hepatitis, thrombocytopenia, and hemolytic anemia. Cytomegalovirus adrenalitis in premature infants, however, is rare. This report described a premature newborn who had progressively worsening hyperbilirubinemia, pancytopenia, and hepatosplenomegaly at the age of 4 days. The baby's mother had prolonged rupture of amniotic membrane for about 8 weeks. The infant received exchange blood transfusion, empiric antibiotics treatment, and mechanical ventilation. Pneumonia and sepsis developed at the age of 18 days. Serum anticytomegalovirus immunoglobulin M and urine virus culture were positive for cytomegalovirus. The baby died at the age of 22 days. Autopsy showed cytomegalovirus infection complicated with interstitial pneumonitis and pulmonary edema, subacute bronchopulmonary dysplasia with interstitial fibrosis, and adrenalitis. We concluded that the functional status of the adrenal glands in cytomegalovirus-infected premature newborns who have unexplained electrolytes imbalance, fever, diarrhea, weight loss, or hypotension should be closely followed because of the possible involvement of adrenal glands.

Adrenal Gland Diseases↗

PubMed2000

Migration of endoclip into duodenum. A rare complication after laparoscopic cholecystectomy.

The long-term effect of spilled clips within the abdominal cavity after laparoscopic cholecystectomy is unknown. However, most surgeons agree that the migration of clips has limited clinical consequences. A few cases have been reported of clips that have migrated into the common bile duct, causing stone formation and/or obstructions. We present a case of gallstone pancreatitis treated with laparoscopic cholecystectomy that was complicated by bile leakage from the cystic duct stump 1 day after the procedure. Although the leaking stump sealed itself spontaneously after the placement of a biliary stent, a clip had migrated directly to the superior wall of the first portion of the duodenum. Herein the details of the patient's history are presented. We also discuss the possible mechanisms of clip migration and describe some preventive measures.

Bile↗

PubMed2000

Outflow tract reconstruction in living donor liver transplantation.

BACKGROUND: Hepatic venous reconstruction is critical in living donor liver transplantation because outflow obstruction may lead to graft dysfunction or loss. We describe our experience and analyze outcomes with a technique of creating a single outflow tract using venoplasties of the graft and recipient hepatic veins. PATIENTS AND METHODS: A retrospective study was done on 38 consecutive living donor liver transplants performed from June 1994 to March 2000. The grafts included 36 left-side grafts and 2 right-side grafts. Nine grafts had multiple hepatic veins and required a venoplasty of two or three hepatic veins to create a single outflow orifice. Triple recipient hepatic venoplasty was performed in 32 patients, double venoplasty in 5 and none in 1. RESULTS: There were four cases of outflow obstruction, three occurring in patients with a double recipient venoplasty. Two of the problems were remedied intraoperatively by adjusting the position of the graft although two were structural in nature and required the insertion of expandable metallic vascular stents. All donors and recipients with their original grafts are alive at a mean follow-up period of 27 months. CONCLUSION: A triple recipient venoplasty with a matching venoplasty of multiple graft hepatic veins to create a single wide outflow orifice is recommended in living donor liver transplantation using left side grafts.

Adolescent↗

PubMed2000

A prokaryote and human tRNA synthetase provide an essential RNA splicing function in yeast mitochondria.

Mitochondrial leucyl-tRNA synthetase (LeuRS) in the yeast Saccharomyces cerevisiae provides two essential functions. In addition to aminoacylation, LeuRS functions in RNA splicing. The details of how it came to act in splicing are not known. Here we show that Mycobacterium tuberculosis and human mitochondrial LeuRSs can substitute in splicing for the S. cerevisiae mitochondrial LeuRS. Mutations of yeast mitochondrial LeuRS that had previously been shown to abolish splicing activity also eliminate splicing by the M. tuberculosis enzyme. These results suggest the role of LeuRS in splicing in yeast mitochondria results from features of the enzyme that are broadly conserved in evolution. These features are not likely to be designed for splicing per se, but instead have been adopted in yeast for that purpose.

Amino Acid Sequence↗