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T Huynh

Publications and source records attributed to T Huynh.

At least 55 records · Page 3Linked to original sources
PubMed1995

Gonadal steroids modulate interleukin-1 receptor antagonist mRNA expression in cultured human monocytes.

This study investigated whether gonadal steroids modulate the expression of the cytokine Interleukin-1 receptor antagonist in monocytes. Human male peripheral monocytes were isolated and cultured in serum free media with serially diluted concentrations of estradiol and progesterone. mRNA expressions with increasing steroid concentrations were compared by reverse transcription-polymerase chain reaction for intracellular and secretory interleukin-1 receptor antagonist specific primers and glyceraldehyde 3-phosphate dehydrogenase primers. Monocyte expression of secretory Interleukin-1 receptor antagonist mRNA was significantly elevated in the presence of normal physiological levels of estradiol (10(-11) M) and progesterone (10(-8) M), while expression was suppressed by higher concentrations of steroids. Intracellular receptor antagonist was also detected. This study is the first to describe the dose related response of cytokine interleukin-1 receptor antagonist to gonadal steroids.

Base Sequence↗
PubMed1995

Immunohistochemical localization, identification and regulation of the interleukin-1 receptor antagonist in the human endometrium.

There is evidence suggesting the importance of the interleukin-1 receptor type I (IL-1Rtl) and interleukin-1 beta (IL-1 beta) as mediator in local intercellular interactions in endometrial tissue and embryonic implantation. To complete our understanding of the entire endometrial IL-1 system in humans, we have investigated the immunohistochemical distribution of IL-1 receptor antagonist (IL-1ra) in the human endometrium throughout the menstrual cycle. We have also identified the forms of IL-1ra present in human endometrial cells. Immunoreactive IL-1ra was found in both cryostat and paraffin-embedded sections of human endometrium using the alkaline phosphatase-peroxidase (A-P) method with two different IL-1ra antibodies. IL-1ra was present throughout the entire menstrual cycle, located primarily in the endometrial epithelium. However, IL-1ra staining was significantly higher during follicular phase in comparison with early and mid-late luteal phases. Reverse transcriptase polymerase chain reaction of cultured stromal and glandular cells showed that these cells express the intracellular form of IL-1ra mRNA (icIL-1ra). Our results demonstrate the regulated presence of the icIL-1ra in the human endometrium. This finding supports a possible autocrine-paracrine role for the IL-1 system in the human endometrium and embryonic implantation.

Adult↗
PubMed1995

Acute pancreatitis. Surgical management.

In general, the best approach to pancreatitis is to recognize its presence early, resuscitate the patient aggressively, and employ nutritional and medical therapy to avoid complications. Nonetheless, either because of trauma or failure of medical therapy, some patients develop complications (e.g., hemorrhagic or necrotizing pancreatitis, abscess, pseudocyst, or fistula) that require operative intervention. Expert surgical judgment is required to decide which patients require surgery, when to operate, and what operation(s) to perform. Many of these patients require multiple surgical procedures and are critically ill, requiring careful attention to nutritional support, ventilatory management, and surveillance for sepsis. The care of these patients requires a multidisciplinary approach involving personnel in internal medicine, gastroenterology, radiology, surgery, anesthesiology, and nursing. Pancreatitis does not respect the boundaries of class, race, creed, gender, or traditional specialty interests; only by using a collegial approach, which shares expertise in a multidisciplinary fashion, is it possible to optimize patient care and salvage critically ill patients with this deadly disease.

Acute Disease↗
PubMed1995

Safety profile of 5-h oral sodium phosphate regimen for colonoscopy cleansing: lack of clinically significant hypocalcemia or hypovolemia.

OBJECTIVES: Oral sodium phosphate (NaP), a colonic cleansing agent for colonoscopy that is superior to standard polyethylene glycol-based lavage solutions because of greater patient acceptance, effectiveness, and significantly less cost, causes intravascular volume depletion and hyperphosphatemia. To determine whether these changes may be near the threshold for inducing clinically serious side effects, these parameters were studied in patients receiving two doses of NaP over 5 h rather than the conventional 12-h duration. METHODS: 50 patients (27 outpatients, 23 inpatients) drank 45 ml of NaP at 1700 and 2200 h the night before colonoscopy. Patients with renal failure, active heart disease, ileus, or gross ascites were excluded. RESULTS: Serial blood tests and hemodynamic measurements demonstrated signs of intravascular volume depletion in less than 10% of outpatients but up to 40% of inpatients. None of the patients complained of postural dizziness or presyncope. All patients became hyperphosphatemic (maximum 3.72; normal < 1.30 mmol/L). Measurements of ionized calcium were significantly lower compared with baseline values (mean values 1.19 vs 1.23 mmol/L, respectively). In 44% of patients, these values were below the lower limits of normal (1.19 mmol/L) but these changes were minor (lowest value 1.07 mmol/L) and none of the patients were symptomatic. CONCLUSIONS: This study suggests that oral NaP is a safe agent in most patients for colonic cleansing, even when given using a 5-h regimen.

Blood Volume↗
PubMed1994

Activation of Kupffer cells in vivo following femur fracture.

OBJECTIVE: To test the hypothesis that Kupffer cells are activated after blunt femur fracture leading to altered hepatic oxygen (O2) consumption. DESIGN: Prospective randomized experimental trials. SETTING: Laboratory. MATERIALS AND METHODS: Male Sprague-Dawley rats underwent closed femur fracture with associated soft-tissue injury. Control animals received only anesthesia. After 30 minutes and 2 hours, livers were perfused and fixed. Tissue was processed for scanning and transmission electron microscopy. In separate experiments, hepatic O2 consumption was measured in isolated perfused livers 2 and 48 hours after femur fracture using a Clark-type electrode. Oxygen consumption was calculated from the influent-effluent concentration difference, flow rate, and liver weight. RESULTS: In femur-fractured animals, scanning electron microscopy revealed alterations in Kupffer cell surface characteristics, including increases in cell volume and complex foldings and extensions of the plasma membrane. Transmission electron microscopy showed internal vacuolization and dark-staining granule formation. The changes were more pronounced 2 hours after femur fracture. Hepatic O2 consumption increased significantly at both 2 and 48 hours after femur fracture. Morphologic and functional activation of Kupffer cells were not seen in control animals. CONCLUSION: In vivo ultrastructural evidence shows Kupffer cell activation after closed femur fracture. This activation is associated with increased hepatic O2 consumption, which is present at 2 hours and persists 48 hours following injury. The results suggest that Kupffer cell activation may be related to the acute-phase response following trauma.

Animals↗
PubMed1992

Histamine potentiation by hydroxylamines: structure-activity relations; inhibition of diamine oxidase.

Hydroxylamines potentiated the responses of the canine colonic epithelium to histamine but not to other agonists such as serotonin or carbachol. We tested the hypothesis that an inhibition of histamine catabolism could explain the observed potentiation. A clear structure activity relation was defined, active compounds having the structure NH2-O-R, R being a simple uncharged aliphatic group. Active compounds delayed the disappearance of histamine from the bathing solutions and inhibited colonic diamine oxidase, an effect mimicked by standard inhibitors aminoguanidine and semicarbazide. Histamine agonists that possessed an imidazole nucleus (2- and 4-methylhistamine) were affected, whereas impromidine, 2 pyridylethylamine, and dimaprit were not. Agonist specificity combined with the enzyme data suggest an inhibition of histamine catabolism as a possible mechanism for the potentiating effects observed.

Amine Oxidase (Copper-Containing)↗
PubMed1986

Preparation and characterization of 3-monohydroxylated bile acids of different side chain length and configuration at C-3. Novel approach to the synthesis of 24-norlithocholic acid.

A series of 3-monohydroxylated bile acids, in unlabeled and radioactive form, of varying side chain length and configuration at C-3 has been synthesized and rigorously characterized. They include: 3 alpha- and 3 beta-hydroxy-5 beta-androstane-17 beta-carboxylic acids (C20); 3 alpha- and 3 beta-hydroxy-5 beta-pregnan-21-oic acids (C21); 3 alpha- and 3 beta-hydroxy-23,24-bisnor-5 beta-cholan-22-oic acids (C22); 3 alpha- and 3 beta-hydroxy-24-nor-5 beta-cholan-23-oic acids (C23, norlithocholic and isonorlithocholic acids); and 3 beta-hydroxy-5 beta-cholan-24-oic acid (C24, isolithocholic acid). A novel approach to the degradation of lithocholic acid acetate to 24-norlithocholic acid is described. This degradation involves the photochemical modification of a Hunsdiecker reaction and Kornblum oxidation of the intermediate 23-bromide. The availability of these compounds makes it possible to study the metabolism and biological effects of short chain bile acids.

Bile Acids and Salts↗
PubMed1984

A monoclonal antibody to the double-stranded polyribonucleotide complex poly(A) X poly(U).

A monoclonal antibody to the double-stranded polyribonucleotide complex poly(A) . poly(U) was derived from the fusion of spleen cells from immunized DBA/2 mice and the P3 X X63-Ag8 plasma cytoma. Specificity studies using radioimmunoassays showed that the anti-poly(A) . poly(U) does not cross-react with single-stranded polyribonucleotides. RNA X DNA hybrids or DNAs. In addition to RNA duplexes associating adenine and uracil, it recognizes synthetic poly(I) . poly(C) and naturally occurring reovirus RNA. It is thus directed against a conformational epitope with an absolute requirement for two polyribose phosphate chains. However, the antibody does not cross-react with poly(G) . poly(C) and is therefore able to distinguish between RNA double helices.

Animals↗
PubMed1980

Induction of differentiation of murine erythroleukemia cells by aminonucleoside of puromycin and inhibition of this induction by purines and purine derivatives.

The effect of the aminonucleoside of puromycin (AMS) on Friend erythroleukemia cells in culture was investigated, because purines and purine analogues are known to act as inducers of differentiation. After treatment with 20-30 micro M AMS for 4 days, the cultures contained between 80 and 90% benzidine-positive cells. Stimulation of hemoglobin synthesis was dose and time dependent. Inosine had no stimulatory activity; however, when it was added to the medium together with AMS, erythroid differentiation was almost completely inhibited. The inhibitory effect of inosine on this potent inducer was also dose and time dependent. No cytotoxicity was observed with either compound, alone or in combination. Inhibition of AMS stimulation of erythroid differentiation was also observed in the presence of inosine monophosphate and poly(inosinic acid). Hypoxanthine had a dual effect. At high concentrations (500 microgram/ml) it acted as an inducer, but when added at low concentrations (20 microgram/ml) together with AMS it inhibited differentiation. These findings suggest there is a link between purine biosynthesis and the event(s) required to trigger differentiation. Agonist-antagonist activity of closely related biological compounds has thus been revealed in the erythroleukemia cells.

Animals↗
PubMed1974

Transfection of chicken embryo cells with DNA extracted from avian virus-producing neoplastic cells.

DNA isolated from avian virus-producing leukemic myeloblasts induced the production of viruses, but not morphological transformation, in cultivated chicken fibroblasts. The recovered virus had the same biological characteristics as the original avian myeloblastosis virus (AMV) and produced myeloblastosis and nephroblastomas when injected into chickens. Neutralization experiments with chicken anti-AMV-BAI strain A sera showed an antigenic community between the DNA-transfected virus and the original virus. Virus induced in fibroblasts after treatment with DNA from a viral nephroblastic nephroblastoma line only gave nephroblastoma when injected into chicken. Treatment of chicken embryo cells with DNA extracted from normal chicken embryos did not induce viral production.

Animals↗
PubMedDate not supplied

Toward a principled methodology for neural network design and performance evaluation in QSAR. Application to the prediction of logP.

The prediction of properties of molecules from their structure (QSAR) is basically a nonlinear regression problem. Neural networks are proven to be parsimonious universal approximators of nonlinear functions; therefore, they are excellent candidates for performing the nonlinear regression tasks involved in QSAR. However, their full potential can be exploited only in the framework of a rigorous approach. In the present paper, we describe a principled methodology for designing neural networks for QSAR and estimating their performances, and we apply this approach to the prediction of logP. We compare our results to those obtained on the same molecules by other methods.

Algorithms↗