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Biomedical subjects

E Tang

Publications and source records attributed to E Tang.

At least 37 records · Page 2Linked to original sources
PubMed1995

The application of the human beta-globin gene locus control region and murine erythroleukemia cell system to the expression and pharmacological characterization of human endothelin receptor subtypes.

The cDNAs encoding both A and B subtypes of the human endothelin receptor have been inserted into mammalian cell expression vectors that utilize the human globin gene, locus control region. These constructs have been introduced into murine erythroleukemia cells and inducible high level expression of the receptors has been achieved (approximately 1.5-pM/mg membrane protein and approximately 13,500 binding sites/cell for both receptor subtypes). Cell lines expressing these receptors were obtained on a rapid time scale (3-4 weeks), facilitated by the need for the analysis of only small numbers of cell clones/receptor (approximately 6). Competitive binding assays with endothelin-1 gave IC50s of 130 +/- 30 pM for endothelin-A receptor and 160 +/- 30 pM for endothelin-B receptor. Similar studies with the different isoforms of endothelin, sarafatoxin-S6b and -S6c, BQ123 and BQ3020, all gave the expected selectivity profiles. The IC50s for all compounds were in close agreement with those reported for native receptors. Thus, this expression system, which has several advantages over other described expression systems, is capable of rapidly providing large quantities of receptor for detailed pharmacological analyses or drug screening. In addition, the expressed receptors display the expected pharmacological profiles in the absence of any complicating, competing interactions from other subtypes or binding sites.

Binding, Competitive↗
PubMed1995

The Schizosaccharomyces pombe MBF complex requires heterodimerization for entry into S phase.

In Schizosaccharomyces pombe, MBF is a DNA-binding complex suspected to activate the transcription of genes necessary for entry into S phase. The MBF complex contains both p85cdc10 and p72res1/sct1. To obtain a better understanding of how the MBF complex regulates gene expression at the G1/S transition, we have performed a genetic analysis of p72res1. We determined that p72res1 can bind specifically to the cdc22 promoter, when analyzed by gel mobility shift assay, and that the N-terminal 157 amino acids of p72res1 are sufficient for this specific binding. When overexpressed in vivo, a fragment of p72res1 containing this DNA-binding domain could rescue a strain carrying a temperature-sensitive cdc10 allele at the restrictive temperature as well as a strain with a cdc10 null allele. We also determined that the C-terminal region of p72res1 is necessary and sufficient for binding to p85cdc10. Overexpression of the cdc10-binding domain of p72res1 leads to a G1 arrest with a cdc phenotype and a decrease on MBF activity. Overexpression of full-length p72res1 also leads to a growth arrest that can be rescued by overexpression of p85cdc10. These results imply that the MBF activity in vivo is dependent on the interaction of p85cdc10 with p72res1.

Base Sequence↗
PubMed1994

Optic gliomas in neurofibromatosis type 1: role of visual evoked potentials.

Optic gliomas occur in 15% of patients with neurofibromatosis type 1 (NF 1) and are a significant cause of morbidity. Of these tumors, 20-30% become symptomatic, usually before age 10 years. Previous studies have suggested that visual evoked potentials (VEPs) are a sensitive method for the detection of asymptomatic optic gliomas. Because routine neuroimaging of children with NF 1 is currently not recommended, the role of pattern-shift VEPs (PS VEPs) as a screening test for optic gliomas was evaluated. PS VEPs were performed on 10 children with NF 1 and optic gliomas and 20 children with NF 1 and normal visual pathways (as defined on MRI). PS VEPs had 90% sensitivity for detecting optic gliomas, with an increase in sensitivity to 100% when hemifield stimulation was used. The specificity of the test was 60%. Four of 20 children without optic gliomas had thickened optic nerves on computed tomography which represented dural ectasia with normal visual pathways on MRI; PS VEPs were normal in these patients. The efficacy of PS VEPs as a routine screen for optic gliomas is limited by the age at which children will cooperate with the test procedure and the high incidence of false-positive results; however, VEPs do provide a useful adjunct to routine clinical ophthalmologic assessment in the detection of optic gliomas in children with NF 1. Abnormal test results provide a stronger indication for neuroimaging. The early detection of optic gliomas allows for close monitoring of tumor progression and earlier intervention prior to significant visual loss.

Adolescent↗
PubMed1994

Intravenous pyelography in penetrating trauma.

Intravenous pyelograms (IVPs) are routinely used in the workup of suspected urologic injuries. The indications for obtaining IVPs have not been well characterized. This study examined 67 patients with penetrating trauma who received formal IVPs with nephrotomography in the radiology department. Of 35 stab wounds, 19 patients presented without hematuria and accounted for only one positive IVP. No intervention was undertaken in this patient. There were 14 stab wound patients with microscopic hematuria, with three positive IVPs. No intervention was necessary in any of these patients. The two remaining stab wound patients both had gross hematuria and renal injuries requiring intervention. However, only one of the two had a positive IVP, showing a blurred kidney margin. One patient had a pseudoaneurysm of a branch of the renal artery, and the other had an arteriovenous fistula. Of 32 patients with gunshot wounds, 15 presented without hematuria. Of the 15, one had a positive IVP but did not have a renal injury on exploration. None of the other 13 patients in this group undergoing exploration had renal injuries. Of the 11 patients with microscopic hematuria, three had hematomas and one had gross extravasation on IVP. Of the six patients with gross hematuria, three had positive IVPs, showing a hematoma, a renal fracture, and indistinct renal outline, respectively. In this limited study, omitting IVPs on the patients with negative urinalyses would not have missed any significant injuries. We suggest that more study is needed in this area because our present standard may lead to unnecessary expense and delay.

Adolescent↗
PubMed1993

Prognostic indicators in fungemia of the surgical patient.

OBJECTIVE: The objective of this study is to identify prognostic factors affecting mortality in surgical patients with culture-proved fungemia and to examine how amphotericin B affects mortality after controlling for these factors. DESIGN: The study is based on a retrospective logistic regression analysis of general surgical patients with blood cultures positive for fungi. We analyzed the patients' ages; whether they received triple antibiotics, had diabetes, had malignant neoplasia, received steroids, had concomitant bacteremia, or took antibiotics for greater than 7 days; and total dose of amphotericin B. SETTING: The study was carried out at a university-based county hospital. PATIENTS: Analysis of microbiology records for blood cultures that were positive for fungi from November 1987 to January 1992 revealed 63 general surgical patients. Patients with burns and those undergoing organ transplantation were excluded. Forty charts were complete and available for review. MAIN OUTCOME: Death was the outcome variable studied. RESULTS: Stepwise logistic regression analysis of death revealed age to be a risk factor for mortality. Treatment with at least 210 mg of amphotericin B was associated with relative risk of death of 0.055. CONCLUSION: Amphotericin B is effective even at low doses at decreasing the mortality in surgical patients with fungemia. On the other hand, increasing age is associated with an increased risk of mortality. Found not to be associated were concomitant bacteremia, concurrent triple antibiotic therapy, malignant neoplasia, and steroid use.

Age Factors↗
PubMed1993

Antigenic analysis of coxsackievirus B3 with monoclonal antibodies.

All the 16 mouse monoclonal antibodies (McAbs) raised against Nancy strain of coxsackievirus B3, CoxB3(N), were type 3-specific. The reactivity of CoxB3(N) to this McAb panel during the serial passages showed a variation. Three field isolates of CoxB3, all neutralizable with the reference Anti-CoxB3 hyperimmune serum, were checked for the reactivities with the McAb panel. The isolates from the patients in Fujiang reacted with 12 McAbs and variably with the remaining four McAbs. On the basis of the reactivities with different virus strains, the McAbs were found to fall into four groups possibly corresponding to at least four epitopes. A considerable antigenic variation of CoxB3 was thus suggested.

Animals↗
PubMed1993

Soft X-ray microimages of immunogold-labelled tumor cell surface antigens.

After successfully introducing the colloidal immunogold labelling technique to soft X-ray contact microscopy (SXCM), SXCM replica microimages of immunogold labelled tumor cell HLA-A2 surface antigens have been acquired for the first time. A biological sample preparation method using immunocytochemical staining techniques suitable for SXCM has also been established.

Antibodies, Monoclonal↗
PubMed1991

Hepatitis C virus. A review.

Hepatitis C virus has been shown to be responsible for most cases of posttransfusion hepatitis, as well as for sporadic non-A, non-B viral hepatitis. Hepatitis C virus has also been implicated in the development of primary hepatocellular carcinoma, autoimmune hepatitis, and fulminant viral hepatitis. Although the role of the parenteral transmission of hepatitis C virus is well established, its route of transmission in cases of sporadic infection remains unclear. Sexual transmission is suspected but not confirmed. Recent work regarding treatment has shown interferon alfa to be effective, but the discontinuation of therapy is associated with a 50% relapse rate.

Blood Transfusion↗
PubMed1991

[The application of immunofluorescence and neutralization McAb tests to typing diagnosis of 286 polio strains].

The serum neutralization test is a classical method used for typing poliovirus. Since 1987, some type-specific non-neutralization McAb's have been obtained in our laboratory, and were used in indirect immunofluorescence straining tests to detect serotypes I, II and III. A total of 286 poliovirus strains were typed by the indirect immunofluorescence test (IF) and neutralization test (NT). The results demonstrated that both tests were in agreement, suggesting that McAb IF could replace NT as an alternative typing diagnostic method: moreover, IF was easier to perform than NT. It is economical and rapid (the results can be read within 1-2 days as compared to 7 days for NT). The reagent is very stable and can be stored for two years at 4 degrees C or for two months at 37 degrees C.

Antibodies, Monoclonal↗
PubMed1989

Laminate veneers for the aesthetic restoration of anterior teeth.

The conservative aesthetic restoration of unsightly anterior teeth has been revolutionized by the introduction of laminate veneers. Although direct composite veneers and pre-fabricated acrylic veneers have been used, the long-term clinical results are not as completely satisfactory as the laboratory-fabricated veneers. At present, indirect laboratory-made resin veneers and porcelain laminate veneers have become the two major modalities of treatment when conservative aesthetic restoration of anterior teeth is needed. In this article, details on these two types of veneers and steps of bonding them to the teeth are presented. Furthermore, colour modifications prior to veneer cementation, temporization of tooth preparations, long-term gingival response to veneer margins, and durability of the veneers have been reviewed.

Acrylic Resins↗
PubMed1986

Thyroid hormone regulation of epidermal growth factor receptor levels in mouse mammary glands.

The specific binding of iodinated epidermal growth factor ([125I]iodo-EGF) to membranes prepared from the mammary glands and spontaneous breast tumors of euthyroid and hypothyroid mice was measured in order to determine whether thyroid hormones regulate the EGF receptor levels in vivo. Membranes from hypothyroid mammary glands of mice at various developmental ages bound 50-65% less EGF than those of age-matched euthyroid controls. Treatment of hypothyroid mice with L-T4 before killing restored binding to the euthyroid control level. Spontaneous breast tumors arising in hypothyroid mice also bound 30-40% less EGF than tumors from euthyroid animals even after in vitro desaturation of the membranes of endogenous growth factors with 3 M MgCl2 treatment. The decrease in binding in hypothyroid membranes was due to a decrease in the number of binding sites, not to a change in affinity of the growth factor for its receptor, as determined by Scatchard analysis of the binding data. Both euthyroid and hypothyroid membranes bound EGF primarily to a single class of high affinity sites [dissociation constant (Kd) = 0.7-1.8 nM]. Euthyroid membranes bound 28.4 +/- (SE) 0.6 fmol/mg protein, whereas hypothyroid membranes bound 15.5 +/- 1.0 fmol/mg protein. These data indicate that EGF receptor levels in normal mammary glands and spontaneous breast tumors in mice are subject to regulation by thyroid status.

Animals↗
PubMed1986

Multiple stenoses of the small intestine by metastatic spread from breast cancer.

We present a patient who had a left mastectomy for breast cancer and 3 years later developed intestinal obstruction due to metastatic spread to the small bowel. The small bowel follow through showed multiple stenoses of the small intestine leading to a variety of differential diagnostic considerations as metastatic spread from breast cancer to the small intestine has not been convincingly documented so far.

Adenocarcinoma, Mucinous↗
PubMed1985

Tracheopathia osteoplastica in the larynx.

Reports of tracheopathia osteoplastica localized to the larynx are few. Such a rare case is reported in a 66-year-old male with life-long symptoms resulting in tracheotomy and resection of some of the osteoplastic tissue. A review of the disease and a discussion about aetiology are described.

Aged↗
PubMed1984

[Neodymium:YAG laser in dermatologic therapy].

We report on our experiences with a powerful neodymium:YAG-laser in treatment of benign and malignant skin tumors as well as various other conditions such as removal of tattoos. The rapidity of the laser treatment which can be carried out under local anaesthesia, allows the treatment of even large tumors in critical locations as well as in the elderly. The cosmetic results are comparable to those obtained by dermatologic X-ray therapy. Before complete healing of the coagulated area is achieved, however, a rather long period elapses. The cosmetic outcome after removal of tattoos largely depends on the level of the dermis the pigment is deposited in; all in all, our results are not superior to other treatment schedules.

Adult↗
PubMed1975

Effect of Acinetobacter glutaminase-asparaginase treatment on free amino acids in mouse tissues.

Acinetobacter glutaminase-asparaginase (AGA) and Escherichia coli asparaginase were compared for their effects on plasma and tissue levels of amino acids, ammonia, and glutamyl transferase activity in the mouse. Free asparagine was depleted similarly in plasma and tissues by both enzymes. AGA treatment produced partial depletion of glutamine concentrations in muscle, spleen, small intestine, and liver. Brain and kidney glutamine concentrations actually rose with treatment. Despite over 100-fold increase in plasma glutamate, only the kidney showed a substantial increase in free glutamate levels during AGA treatment. Glutamine biosynthesis measured by glutamyl transferase activity showed an appreciable increase only in the kidney. Ammonia levels in tissues and plasma rose 1.3- to 4.3-fold. In general, E. coli asparaginase treatment had much less effect on these measurements than did AGA. The changes in these levels are discussed in relation to sites of possible toxicity and antitumor effects.

Acetyltransferases↗