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A Chin

Publications and source records attributed to A Chin.

At least 19 recordsLinked to original sources
PubMed2005

Removal of disinfection by-product precursors with ozone-UV advanced oxidation process.

The efficacy of using ozone (O3), ultraviolet irradiation (UV) and the combined O3-UV advanced oxidation process (AOP) to remove 2 classes of disinfection by-product (DBP) precursors from raw surface water samples have been evaluated and compared. In particular, trihalomethane and haloacetic acids formation potentials were measured. Laboratory batch scale experiments were carried out as a function of ozone and UV dosage in order to study the removal kinetics. It is concluded that the combined O3-UV AOP is more effective than either the ozone or UV treatment alone. Ozone-UV AOP is capable of mineralizing up to 50% of the total organic carbon from the raw source water at an ozone dose of 0.62+/-0.019 mg O3/mL and a UV dose of 1.61 W s/cm2. In addition, O3-UV AOP can reduce trihalomethane formation potential by roughly 80% and haloacetic acids formation potential by roughly 70% at the same ozone and UV dosage.

Acetates↗
PubMed2004

Irradiation of mechanically-injured human arterial endothelial cells leads to increased gene expression and secretion of inflammatory and growth promoting cytokines.

Radiation therapy is applied to inhibit neointima formation after percutaneous transluminal coronary angioplasty (PTCA). In this study, we evaluated the effect of irradiation on re-endothelialisation of circular denuded tracks made in post-confluent cultures of arterial endothelial cells (ECs) and on cellular factors involved in this process. Image analysis and time-lapse microcinematography revealed cell migration into denuded areas starting 4h after injury. Fifty percent coverage was achieved at 14.8 +/- 2.0 h. Using competitive PCR and flow cytometry techniques, no significant changes in mRNA expression of interleukin-1beta (IL-1beta), interleukin-8 (IL-8), basic fibroblast growth factor (bFGF or FGF-2), transforming growth factor-beta1 (TGF-beta1), platelet-derived growth factor A (PDGF-A), platelet-derived growth factor B (PDGF-B) and tissue factor (TF), and surface molecule expression of anti-intercellular adhesion molecule-1 (ICAM-1), anti-vascular cell adhesion molecule-1 (VCAM-1), anti-platelet/endothelial cell adhesion molecule-1 (PECAM-1), MHC-1, TF and Fas were observed. However, injury did significantly (P < 0.05) elevate the release of IL-8 and FGF-2 protein in the cell culture supernatant, as assessed by ELISA. Radiation (15Gy) given immediately after injury did not affect the kinetics of re-endothelialisation up to 48 h, in spite of the fact that no cell divisions were observed. Thereafter cell density decreased and cultures deteriorated. Compared to cultures exposed to injury alone, radiation induced significant (P < 0.05) increases in mRNA levels of IL-8 (1.35 +/- 0.10-fold increase at 4h), FGF-2 (1.62 +/- 0.10-fold at 4h; 1.76 +/- 0.33-fold at 24h) and IL-1beta (2.76 +/- 0.40-fold at 24h), whereas mRNA levels of TGF-beta1, PDGF-A and PDGF-B increased about 1.2-fold. IL-8 and FGF-2 protein concentrations in the media were higher than those observed in non-irradiated injured cell cultures; however, this difference was not significant. Radiation induced a 2.3 +/- 0.3-fold increase (P < 0.05) in Fas surface expression only. In conclusion, irradiation of mechanically-injured human EC leads to increased gene expression and protein secretion of inflammatory and growth promoting cytokines.

Cell Adhesion Molecules↗
PubMed2004

Humoral response and susceptibility of five full-sib families of Atlantic salmon, Salmo salar L., to the haemoflagellate, Cryptobia salmositica.

Susceptibility and antibody production against pathogenic and vaccine strains of the haemoflagellate, Cryptobia salmositica were investigated in five full-sib families (A-E) of Atlantic salmon, Salmo salar. Humoral response and susceptibility of families were compared within three treatments: infection, vaccination and vaccination followed by challenge. Parasitaemias caused by the vaccine strain of C. salmositica were considerably lower than those caused by the pathogenic strain. All vaccinated families were protected when challenged with the pathogenic strain. Family B had significantly lower parasitaemias (with both strains) than the other families. When naïve fish were infected with the pathogenic strain, this family had a significantly lower and earlier peak parasitaemia (4.3 +/-1.3 x 10(6) parasites mL(-1) blood at 3 weeks post-infection; w.p.i.) than the other families. Family C had the highest peak (11.1 +/- 1.2 x 10(6) parasites mL(-1) blood), which occurred at 4 w.p.i. Antibodies against C. salmositica were detected earlier in Family B (3 w.p.i.) than in Family C (5 w.p.i.). This demonstrates an association of increased susceptibility with a delayed antibody response. Western immunoblot identified antibodies against 112, 181 and 200 kDa antigens earlier in more resistant fish (Family B). Antigenic stimulation leading to a stronger antibody response was shown with the vaccine strain and in the later stages of infection.

Analysis of Variance↗
PubMed2004

Construction and evaluation of cDNA libraries for large-scale expressed sequence tag sequencing in wheat (Triticum aestivum L.).

A total of 37 original cDNA libraries and 9 derivative libraries enriched for rare sequences were produced from Chinese Spring wheat (Triticum aestivum L.), five other hexaploid wheat genotypes (Cheyenne, Brevor, TAM W101, BH1146, Butte 86), tetraploid durum wheat (T. turgidum L.), diploid wheat (T. monococcum L.), and two other diploid members of the grass tribe Triticeae (Aegilops speltoides Tausch and Secale cereale L.). The emphasis in the choice of plant materials for library construction was reproductive development subjected to environmental factors that ultimately affect grain quality and yield, but roots and other tissues were also included. Partial cDNA expressed sequence tags (ESTs) were examined by various measures to assess the quality of these libraries. All ESTs were processed to remove cloning system sequences and contaminants and then assembled using CAP3. Following these processing steps, this assembly yielded 101,107 sequences derived from 89,043 clones, which defined 16,740 contigs and 33,213 singletons, a total of 49,953 "unigenes." Analysis of the distribution of these unigenes among the libraries led to the conclusion that the enrichment methods were effective in reducing the most abundant unigenes and to the observation that the most diverse libraries were from tissues exposed to environmental stresses including heat, drought, salinity, or low temperature.

Expressed Sequence Tags↗
PubMed2001

Effects of tezosentan, a dual endothelin receptor antagonist, on the cardiovascular and renal systems of neonatal piglets.

BACKGROUND/PURPOSE: Endothelin is a potent biological vasoactive mediator in the cardiovascular and renal systems. Little is known of the effects of endothelin antagonism on the developing heart and kidney, and we hope to show that endothelin does have an important role in the cardiovascular and renal systems of the developing neonate. In this study the authors have examined the effects of tezosentan, a nonselective endothelin-A and endothelin-B receptor antagonist designed for parenteral use, on the cardiovascular and renal systems of healthy neonatal piglets. METHODS: Eight, 7- to 10-day old domestic piglets weighing 2.5 to 3.0 kg were anesthetized, intubated, and ventilated with catheters placed into the jugular vein, left ventricle, and femoral artery. Urine output was monitored via a suprapubic cystostomy. After baseline data were obtained the piglets received tezosentan (1 mg/kg/h) for 1 hour. A set of data was collected just before discontinuation of the 1-hour infusion of tezosentan and another set was collected 1 hour after the discontinuation of the drug. Mean arterial pressure (MAP), heart rate (HR), and urine output (UV) were monitored continuously and cardiac index (CI), systemic vascular resistance (SVR), renal blood flow (RBF), and renal vascular resistance (RVR) were calculated from gamma counts obtained from injections of radio-labeled microspheres at end of the different time periods. Glomerular filtration rate (GFR) was obtained by the sodium iothalamate method. Data were averaged and plotted versus time and analyzed statistically by a Student's t test. RESULTS: (P <.05 versus baseline*). In our experimental animals the infusion of tezosentan diminished MAP and SVR from baseline values of 94 +/- 7 mm Hg and 0.14 +/- 0.03 mm Hg/mL/min, respectively to TEZO values of 62 +/- 4* mm Hg and 0.07 +/- 0.02* mm Hg/mL/min. CI increased from 278 +/- 58 to 367 +/- 75* mL/min/kg with tezosentan. There also was a statistically significant increase in RBF from 1.16 +/- 0.38 to 1.86 +/- 0.37* mL/min/kg, an increase in UV from 0.57 +/- 0.24 to 0.64 +/- 0.12* mL/min, a decrease in RVR from 4.60 +/- 1.47 to 2.03 +/- 0.36* mm Hg/mL/min, and no change in the GFR. CONCLUSIONS: The inhibition of endothelin receptors with tezosentan produced a statistically significant effect on the piglet cardiovascular system with a drop in MAP and SVR and an increase in CI and HR. It also produced a statistically significant increase in RBF and UV and a decrease in RVR without affecting GFR. J Pediatr Surg 36:1824-1828.

Animals↗
PubMed2000

Automated analysis of normal and glaucomatous optic nerve head topography images.

PURPOSE: To classify images of optic nerve head (ONH) topography obtained by scanning laser ophthalmoscopy as normal or glaucomatous without prior manual outlining of the optic disc. METHODS: The shape of the ONH was modeled by a smooth two-dimensional surface with a shape described by 10 free parameters. Parameters were adjusted by least-squares fitting to give the best fit of the model to the image. These parameters, plus others derived from the image using the model as a basis, were used to discriminate between normal and abnormal images. The method was tested by applying it to ONH topography images, obtained with the Heidelberg Retina Tomograph, from 100 normal volunteers and 100 patients with glaucomatous visual field damage. RESULTS: Many of the parameters derived from the fits differed significantly between normal and glaucomatous ONH images. They included the degree of surface curvature of the disc region surrounding the cup, the steepness of the cup walls, the goodness-of-fit of the model to the image in the cup region, and measures of cup width and cup depth. The statistics of the parameters were analyzed and were used to construct a classifier that gave the probability, P(G), that each image came from the glaucoma population. Images were classified as abnormal if P(G) > 0.5. The probabilities assigned to each image were in most cases close to 0 (normal) or 1 (abnormal). Eighty-seven percent of the sample was confidently classified with P(G) < 0.3 or P(G) > 0.7. Within this group, the overall classification accuracy was 92%. The overall accuracy of the method (the mean of sensitivity and specificity, which were similar) in the whole sample was 89%. CONCLUSIONS: ONH images can be classified objectively and dependably by an automated procedure that does not require prior manual outlining of disc boundaries.

Adult↗
PubMed1998

Mixed effects of 2,6-dithiopurine against cyclophosphamide mediated bladder and lung toxicity in mice.

2,6-Dithiopurine (DTP) has been proposed as a possible chemopreventive agent because of its ability to react with electrophiles. Acrolein, an electrophilic metabolite of cyclophosphamide (CP) involved in the toxicities of this anticancer drug, can be scavenged by DTP. The present study examined the effect of DTP treatment on CP-mediated bladder and lung toxicity in male ICR mice. Mice fed a diet containing 4% DTP that were treated intraperitoneally (i.p.) with 350 mg/kg CP showed no significant bladder damage (measured as bladder blood content at 48 h) with respect to the group fed a control diet. DTP (50 and 100 mg/kg), given i.p. 0.5 and 7 h after the initial injection of CP, also prevented the bladder damage when compared with the group receiving CP alone. Surprisingly, although neither parenteral CP nor DTP alone caused any mortality at these doses, the combined treatment resulted in 67% mortality within 3 days. At 24 h after CP + DTP, blood urea nitrogen was elevated 6-fold and urine volumes decreased by 70%. Histopathological analyses revealed a diffuse myocardial degeneration and necrosis, severe granular degeneration in the liver, abundant cellularity and infiltrates in interalveolar spaces in the lung and swollen nephron epithelial cells with some necrosis. All mice survived treatment when the dose of CP was lowered to 250 and 25-75 mg/kg DTP was given i.p. 0.5 and 7 h after CP. These DTP regimens reduced the degree of CP-induced lung toxicity, measured by [3H]thymidine incorporation into lung DNA 7 days after CP, in a dose-dependent manner. DTP (75 mg/kg) also reduced CP-induced lung fibrosis estimated by lung hydroxyproline content 28 days after CP. Analyses of urine from mice given CP + DTP revealed large amounts of the metabolic product dithiouric acid, smaller amounts of the parent DTP and several smaller peaks. The major unique metabolite peak was collected and analyzed by mass spectrometry, but did not correspond to either acrolein-DTP or acrolein-dithiouric acid. Thus, either very small amounts of an acrolein adduct are generated, the adduct is broken down to an unidentified product, or the ability of DTP to prevent CP-induced lung and bladder damage is related to some other mechanism. The possibility that mercapturic acid metabolites of acrolein released the parent electrophile in the urine was not supported by the finding that probenecid did not prevent CP-induced bladder toxicity.

Animals↗
PubMed1998

Additive effect of concomitant multiple low-dose doxorubicin and thoracic irradiation on ex vivo cardiac performance of the rat heart.

The effects of doxorubicin alone or combined with local heart irradiation on ex vivo cardiac performance were studied in Sprague-Dawley rats. Rats were treated with doxorubicin either administered as a single bolus injection or administered weekly during a period of 10 weeks. In "combined" experiments, local heart irradiation with a single dose of 15 Gy was given prior to drug administration. Evaluation of cardiac performance was performed 14 weeks after initiation of treatment. At drug doses that were tolerated by the rat, single injections with doxorubicin (sd-DXR; up to a dose of 5 mg/kg) did not lead to a change in cardiac performance whereas multiple injections with low-dose doxorubicin (mld-DXR; up to a cumulative dose of 20 mg/kg) led to a dose-dependent decrease in cardiac function. Extracardial toxicity as a result of mld-DXR (cumulative dose < or =15 mg/kg) was mild when compared to the toxicities observed after sd-DXR (5.0 and 7.5 mg/kg). When administration of mld-doxorubicin was preceded by 15 Gy, cardiac performance further decreased. The present data indicate that the interaction between doxorubicin and local heart irradiation with a dose of 15 Gy is additive, when the treatments are given concomitantly. Irradiation did not lead to an increase of DXR-mediated extracardial toxicities. The isolated working rat heart preparation offers a reliable method to evaluate the effects of doxorubicin and new anthracycline analogue on the heart.

Animals↗
PubMed1998

Initial presentation of hepatocellular carcinoma as a mandibular mass: case report and review of the literature.

Hepatocellular carcinoma metastatic to the oral cavity is a rare phenomenon. From 1957 to date, 51 case have been documented in the English literature. In this report we describe a case of metastatic hepatocellular carcinoma manifesting itself as unilateral mandibular paresthesia before the discovery of the primary tumor. In addition, we review the literature related to metastatic hepatocellular carcinoma and the pathways of metastasis.

Aged↗
PubMed1997

Bcl-xL overexpression attenuates glutathione depletion in FL5.12 cells following interleukin-3 withdrawal.

Bcl-xL and bax are bcl-2-related genes whose protein products either inhibit or promote apoptosis. Oxidative damage, including the loss of glutathione, has been implicated in the induction of apoptosis. The ability of the Bcl proteins to affect GSH was assessed in control, bax- and bcl-xL-transfected FL5.12 cells [an interleukin (IL)-3-dependent murine prolymphocytic cell line]. Overall levels of GSH were approximately the same in control and bcl-xL transfectants during the 6 h incubation period, although levels increased in bcl-xL transfectants 24 h after replating. GSH in cells overexpressing bax was reduced by approximately 36%. There were no consistent differences between these cell lines in the activities of superoxide dismutase, catalase, glutathione peroxidase or glutathione reductase. Following IL-3 withdrawal, a condition known to cause apoptosis in these cells, a rapid loss of intracellular GSH occurred in control and bax transfectants, which preceded the onset of apoptosis. GSH depletion could not be attributed to intracellular oxidation but rather seemed to occur due to a translocation out of the cell. Cells overexpressing bcl-xL did not lose significant amounts of GSH upon withdrawal of IL-3, and no apoptosis was evident. These results suggest a possible role for GSH in the mechanism by which bcl-xL prevents cell death.

Animals↗
PubMed1997

Left-right pattern of cardiac BMP4 may drive asymmetry of the heart in zebrafish.

The first evident break in left-right symmetry of the primitive zebrafish heart tube is the shift in pattern of BMP4 expression from radially symmetric to left-predominant. The midline heart tube then 'jogs' to the left and subsequently loops to the right. We examined 279 mutations, affecting more than 200 genes, and found 21 mutations that perturb this process. Some cause BMP4 to remain radially symmetric. Others randomize the asymmetric BMP4 pattern. Retention of BMP4 symmetry is associated with failure to jog: right-predominance of the BMP4 pattern is associated with reversal of the direction of jogging and looping. Raising BMP4 diffusely throughout the heart, via sonic hedgehog injection, or the blocking of its action by injection of a dominant negative BMP4 receptor, prevent directional jogging or looping. The genes crucial to directing cardiac asymmetry include a subset of those needed for patterning the dorsoventral axis and for notochord and ventral spinal cord development. Thus, the pattern of cardiac BMP4 appears to be in the pathway by which the heart interprets lateralizing signals from the midline.

Animals↗
PubMed1996

Isolation and sequencing of the rat Coq7 gene and the mapping of mouse Coq7 to chromosome 7.

We recently identified the Saccharomyces cerevisiae COQ7 gene and showed that its product affects one or more monoxygenase steps in the synthesis of ubiquinone. Other investigators have independently isolated the yeast COQ7 gene as CAT5 and identified it as a gene necessary for the derepression of gluconeogenic enzymes in yeast. In the present study, a homolog of the yeast COQ7 (CAT5) gene was isolated from a rat testis cDNA library by functional complementation of a coq7 deletion mutant of S. cerevisiae. The resulting cDNA clones contained a 0.8-kb insert with an open reading frame encoding a 183-amino-acid polypeptide. The rat Coq7 amino acid sequence is 49% identical to that of yeast Coq7p and 58% identical to a C. elegans homolog over a 152-aa region. Sequence homology searches fail to identify any other significant homologies. The Coq7 gene was mapped to mouse chromosome 7, 7.6 +/- 3.6 cM proximal to the marker D7Mit7, by linkage analysis of an interspecific backcross. This region of chromosome 7 containing Coq7 is part of a linkage group conserved between mouse chromosome 7 and human chromosome 11p15.

Amino Acid Sequence↗
PubMed1996

[Electron beam irradiation is effective in the treatment of skin carcinomas; a comparison with superficial roentgen therapy].

OBJECTIVE: To compare recurrence rates and cosmetic results after electron beam therapy versus superficial X-ray therapy for basal cell and squamous cell carcinomas of the skin. SETTING: Department of Radiotherapy, University Hospital Leiden, the Netherlands. DESIGN: Retrospective. METHODS: A retrospective analysis was performed of 389 histologically confirmed basal cell and squamous cell carcinomas of the skin (1980-1990), treated with either superficial X-rays or electron beam therapy, with regard to local recurrence rates and cosmetics scored with an arbitrary three point scale. RESULTS: Of 389 patients 19 developed a local recurrence (4.9%). For small tumours (irradiated surfaces < or = 10 cm2) a local recurrence rate of 2.2% was observed, both after electron beam therapy and after superficial X-ray therapy. Large tumours (irradiated surface > 50 cm2, treated with electron beam) had a higher recurrence rate (13.8%) as had tumours which had been treated before. The cosmetic results with electron beam treatment were better, because smaller fractions were used compared with superficial X-ray treatment. CONCLUSION: In our hands electron beam treatment was not inferior to superficial X-ray treatment, cosmetically even better and also applicable in case of larger tumours. The inferior results of electron beam therapy reported in literature may be due to technical factors.

Aged↗
PubMed1996

Laparoscopic retropubic urethropexy.

We evaluated a simplified extraperitoneal retropubic bladder suspension using balloon distention and mesh suspension in 100 patients to determine operating time, anesthesia, morbidity, voiding time, length of hospital stay, cost, and patient satisfaction. All cases were performed by the same surgeon. The majority of women were medium build; 28 were obese, and 17 thin. Operating time varied little, with most 89 procedures requiring less than 30 minutes. Either epidural anesthesia or general anesthesia can be used. There were two hematomas and six bladder entries. Voiding time varied from 4 hours up to 2 days, with 87% of patients voiding in less than 18 hours. Hospital stay was less than 24 hours for all but two patients, except when other procedures were associated with the bladder suspension. The average cost of the outpatient procedure was $3220. 00, and inpatient surgery, with a 3-day stay, averaged $6370.00. Ninety-one patients reported they were continent. Nine were classed as failures, of whom six were satisfied with the result. Extraperitoneal, retropubic, bladder mesh suspension results in a durable repair, and is associated with minimal operating time and morbidity and maximum patient satisfaction and clinical benefit.

Adult↗
PubMed1995

Electron beam therapy is not inferior to superficial x-ray therapy in the treatment of skin carcinoma.

PURPOSE: To compare recurrence rates and cosmetic results after electron beam therapy vs. superficial x-ray therapy for nonmelanoma skin carcinoma. METHODS AND MATERIALS: A retrospective analysis was performed on 389 histologically confirmed basal cell and squamous cell carcinomas of the skin, treated with either superficial x-rays or electron beam therapy, with regard to local control rates and cosmetics, as scored with an arbitrary three-point scale. RESULTS: The overall local recurrence rate was 4.9% (19 out of 389). For small tumors (irradiated surfaces < or = 10 cm2) a local recurrence rate of 2.2% was observed, both after electron beam therapy and after superficial x-ray therapy. Tumor size and previous treatment proved to be important prognostic factors with regard to control rate. The well-fractionated electron beam therapy yielded better cosmetic results than the large fraction superficial x-ray therapy. CONCLUSION: Electron beam treatment is not inferior to superficial x-ray treatment and even better for larger tumors. The inferior results of electron beam therapy reported in literature might be due to technical factors, which are discussed.

Aged↗