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Biomedical subjects

N H Nguyen

Publications and source records attributed to N H Nguyen.

At least 19 recordsLinked to original sources
PubMed2005

Responses in residual feed intake in lines of Large White pigs selected for growth rate on restricted feeding (measured on ad libitum individual feeding).

Residual feed intake (RFI) represents the deviation of the actual ad libitum food consumption of each animal from that predicted from combination of growth rate, backfat and metabolic body weight measurements. After 4 years of divergent selection of pigs in lines for either high or low postweaning growth rate on restricted feeding, the high line exhibited a significant reduction in RFI relative to the low line. This indicated, to some extents, a lower energy requirement for maintenance in the high than in the low line, possibly because of reduced physical activity of the animals. Estimates of genetical parameters showed that RFI was moderately heritable and those genetic correlations of RFI with carcass backfat and food conversion ratio were moderate to highly positive.

Adipose Tissue↗
PubMed2004

A novel antigenic variant of Canine parvovirus from a Vietnamese dog.

Nine isolates of Canine parvovirus (CPV) were obtained from Vietnamese dogs and cats. One canine isolate showed a unique antigenic property which indicates a novel antigenic variant of CPV-2b when examined with hemagglutination inhibition tests using our monoclonal antibodies, 21C3 and 19D7, which were recently developed. This isolate had an amino acid substitution of residue 426, Asp to Glu, and the same substitution has recently been found in CPV from Italian dogs. This study first showed that such substitution caused an antigenic difference demonstrable by monoclonal antibodies and that a similar evolution may have occurred in CPV in Vietnam.

Animals↗
PubMed2001

Anaesthesia for a child with progeria.

The Hutchinson-Gilford syndrome, commonly referred to as progeria, is a rare childhood syndrome that results in premature ageing. We focus on two anaesthetics administered to a child with progeria and a review of the available literature.

Anesthesia, General↗
PubMed2001

Selective thyromimetics: tissue-selective thyroid hormone analogs.

Thyroid hormone coordinates a diverse array of physiological events in development and homeostasis. Many of the actions of thyroid hormone are tissue-specific and are primarily mediated by a panel of thyroid hormone receptor isoforms that are expressed in different ratios in different tissues. Because these tissue-specific hormone signaling pathways are linked to a number of metabolic diseases, the development of synthetic thyroid hormone analogs that have tissue-selective hormone actions (i.e., selective thyromimetics) is highly desirable. There is a powerful collection of tools available today for this pursuit including efficient receptor binding and activation assays, receptor structures and a variety of thyroid hormone receptor knockout mice. The medicinal chemistry efforts in this area demonstrate that selective thyromimetics can be produced from a variety of approaches. These compounds are proving useful as probes to better define thyroid hormone actions and may one day find use in the clinic for the treatment of metabolic disorders.

Animals↗
PubMed2000

Improved synthesis of the iodine-free thyromimetic GC-1.

Synthesis of the TRbeta-selective thyromimetic GC-1 has been improved using methoxymethyl (MOM) and triisopropylsilyl (TiPS) substituents as phenolic protecting groups. The new synthetic route is adaptable to analogue design.

Iodine↗
PubMed2000

Anesthetic management for patients with arthrogryposis multiplex congenita and severe micrognathia: case reports.

Arthrogryposis multiplex congenita (AMC) is a spectrum syndrome of multiple persistent limb contractures often accompanied by associated anomalies, including cleft palate, genitourinary defects, gastroschisis, and cardiac defects. Pediatric patients with AMC frequently present for multiple surgeries requiring general endotracheal anesthesia. We describe our anesthetic experience with the laryngeal mask airway and endotracheal tube in two neonates with AMC and severe micrognathia. We discuss AMC and outline the problems encountered in difficult airway management.

Anesthesia↗
PubMed2000

The influence of donor and reservoir additives on Caco-2 permeability and secretory transport of HIV protease inhibitors and other lipophilic compounds.

PURPOSE: To optimize the conditions for determining Caco-2 permeation of HIV protease inhibitors and other lipophilic compounds, and to compare cyclic urea HIV protease inhibitors with marketed compounds. METHODS: Absorptive and secretory Caco-2 membrane permeation studies were performed with HIV protease inhibitors and various reference compounds, examining the effects of adding the solubilizing agents dimethylacetamide (DMAC) and albumin in donor and reservoir compartments, respectively. RESULTS: DMAC was useful as an additive in the donor vehicles, increasing the dissolved concentrations of poorly water-soluble HIV protease inhibitors, and enabling more reliable determination of P(app) values. Donor vehicles containing up to 5% DMAC could be used without altering Caco-2 barrier function, as indicated by the lack of effect on permeabilities of reference compounds with diverse absorption characteristics. The utilization of a reservoir containing albumin resulted in marked increases in absorptive Papp values for some HIV protease inhibitors as well as other lipophilic, highly protein bound compounds, consistent with albumin increasing the release of these compounds from the cell monolayer. CONCLUSIONS: Poorly soluble, lipophilic, highly bound compounds may require using solubilizing agents in the donor and reservoir compartments of Caco-2 permeation experiments for estimating in vivo absorption potential. If the reservoir does not provide adequate sink conditions, cellular retention could over-emphasize the contributions of secretory transport. The cyclic ureas, DMP 450, DMP 850, and DMP 851, have Caco-2 permeabilities suggestive of moderate-to-high oral absorption potential in humans.

Acetamides↗
PubMed2000

Breast tumor contamination of peripheral blood stem cell harvests: increased sensitivity of detection using immunomagnetic enrichment.

Contaminating tumor cells in peripheral blood stem cell (PBSC) grafts infused for hematopoietic rescue after high-dose chemotherapy could potentially contribute to relapse in BrCa patients. To date the prevalence of PBSC contamination in BrCa patients, as determined by standard immuno-cytochemistry (ICC) assays, has generally been found to be relatively low. However, assay sensitivity may have an important impact on the ability to detect contamination. In this investigation a novel and highly sensitive BrCa cell assay using immunomagnetic enrichment with a panel of antiBrCa monoclonal antibodies (MAbs) and detection by ICC has been characterized. The immunomagnetic enrichment with ICC detection (IE-ICC) assay was directly compared with standard ICC in ability to detect BrCa contamination of PBSC specimens from patients with high-risk stage II/III and metastatic disease. The sensitivity of the IE-ICC assay was approximately 50-fold greater than that of standard ICC. As determined by standard ICC assay, BrCa cells were present in 1/14 patients (7%) and 2/26 (8%) specimens. In contrast, with IE-ICC assay the proportions of positive findings in patients (12/14, 86%) and specimens (19/26, 73%) were significantly higher (p = 0.001 and p < 0.0005, respectively). These preliminary findings suggest that the prevalence of PBSC contamination may be substantially higher than previously appreciated. Consequently, measures to reduce tumor contamination in the graft may have the potential to improve patient outcomes. Higher sensitivity assays such as the IE-ICC assay may play an important role in assessing the risks associated with tumor contamination and the effectiveness of tumor-purging approaches such as positive selection of CD34+ cells and in monitoring patient response to therapy.

Antibodies, Monoclonal↗
PubMed2000

Effect of micronized fenofibrate on plasma lipoprotein levels and hemostatic parameters of hypertriglyceridemic patients with low levels of high-density lipoprotein cholesterol in the fed and fasted state.

A randomized, double-blind, placebo-controlled study was undertaken in 20 hypertriglyceridemic men [plasma triglyceride (TG), >2.3 mM] with low levels (<0.9 mM) of high-density lipoprotein cholesterol (HDL-C) to investigate the ability of micronized fenofibrate (Tricor or Lipidil; 200 mg/day) to affect atherogenic and thrombogenic plasma risk factors in the fed and fasted state. Each patient underwent (a) 4 weeks of dietary stabilization, (b) 8 weeks of treatment with fenofibrate or placebo, (c) a 5-week washout period, and (d) 8-weeks of treatment with the alternative medication. An oral fat-loading test (1 g fat/kg body weight) was carried out after both treatment periods. Before treatment, patients had a mean (+/- SD) total plasma TG of 3.31+/-0.93 mM; total C, 5.75+/-0.89 mM; HDL-C, 0.71+/-0.09 mM; and low-density lipoprotein (LDL)-C, 3.40+/-0.68 mM. Compared with placebo, fenofibrate reduced fasting TG levels by 36%, and triglyceride-rich lipoprotein (TRL, d<1.006 g/ml) -TG, and TRL-C levels by approximately 40%. In the postprandial state, fenofibrate reduced total TG, TRL-TG, TRL-C, TRL-apoC-III, and TRL-apoE levels by -35% (all values of p<0.01). Fasted and fed HDL-C and apoA-I levels were increased -10%, and total cholesterol/HDL cholesterol ratios were decreased -15% by fenofibrate. No significant differences were observed in mean LDL-C and LDL-apoB levels. A 6% increase in the LDL-C/LDL-apoB ratio during fenofibrate treatment indicated a shift to larger, more buoyant LDL particles. A small, but statistically significant (p<0.01) increase was observed in fasted and fed Lp(a) levels during fenofibrate treatment. Hemostatic parameters were not significantly affected by fenofibrate, except for a 12-15% decrease (p<0.05) in fibrinogen levels in the fasted and fed state, and a significant increase (43%; p<0.05) in fasting levels of plasminogen activator-inhibitor-1. These data demonstrate that micronized fenofibrate is highly effective, in both the fed and fasted state, in reducing TRL lipids and apolipoproteins, and in reducing plasma fibrinogen levels of men with an atherogenic lipoprotein profile.

Adult↗
PubMed1997

Percutaneous transluminal angioplasty in coronary-internal thoracic-subclavian steal syndrome.

Internal thoracic artery implants are widely used as conduits in coronary artery bypass surgery because of their resistance to the development of atherosclerosis. Two cases are reported of subclavian artery stenosis proximal to the internal mammary artery in patients who had undergone coronary bypass surgery. In both cases, an atypical pattern of postsurgical angina developed, with retrosternal chest pain occurring specifically with upper extremities exercise. Coronary and graft angiography revealed retrograde flow in the left internal thoracic artery during injection of the grafted coronary. Severe stenosis was identified in the subclavian artery. Treatment consisted of dilation of the subclavian artery stenosis with stent placement in one patient. Both patients had marked symptomatic improvement after the procedure.

Angiography, Digital Subtraction↗
PubMed1996

The use of a water extract from the bark of Choerospondias axillaris in the treatment of second degree burns.

Burns are common in Vietnam, and because of economic constraints and limited resources for the import of appropriate treatments, the health authorities are obliged to rely on traditional herbal remedies. It is therefore essential to evaluate current drugs, one of which is the water extract of the bark of the tree Choerospondias axillaris. It has been used for many years in the Vietnam-Sweden hospital at Uong Bi in northern Vietnam. We assessed the efficacy of the remedy in an open, randomised controlled clinical trial, in which 20 patients with second degree burns were treated with the extract of the Choerospondias axillaris and 19 with saline gauze. The mean healing time was significantly shorter for patients treated with Choerospondias axillaris (11 days) compared with patients treated with saline gauze (17 days) (p < 0.01), and the number of wound infections was significantly lower in the Choerospondias axillaris group (7/20 compared with 16/19, p = 0.003). The bark extract was easy to apply and additional wound care was not usually necessary, while the treatment with saline gauze was laborious for both patients and staff and was much more expensive. The extract from Choerospondias axillaris is a convenient treatment for second degree burns in both children and adults.

Adolescent↗
PubMed1994

Characterization of recombinant plasminogen activator production by primate endothelial cells transduced with retroviral vectors.

Retroviral vector-mediated expression of plasminogen activators (PAs) from endothelial cells (ECs) has been proposed as a potential therapeutic approach for intravascular thrombosis. To define the potential for gene transfer to increase fibrinolytic activity in a primate system, baboon ECs were transduced with retroviral vectors expressing wild-type and glycosylphosphatidylinositol-anchored urokinase, as well as wild-type and serpin-resistant tissue PA (t-PA). Expression of either t-PA or urokinase was increased by one log over baseline levels. There was no specific effect of either t-PA or urokinase overexpression on endogenous t-PA, urokinase, or PA inhibitor 1 (PAI-1) expression. Recombinant urokinase could be anchored to the cell surface at a level eight-fold above that of receptor-bound urokinase. The majority of secreted urokinase accumulated in conditioned medium as a free proenzyme, whereas both wild-type and serpin-resistant t-PA accumulated almost exclusively in complexes with PAI-1. In most but not all of the assays, the urokinase vectors conferred PA activity above that of the t-PA vectors. These data show that PA synthesis and activity are specifically increased subsequent to retroviral vector-mediated gene transfer in primate ECs. However, definition of an optimal PA vector will require in vivo experimentation.

Animals↗
PubMed1992

Studies on the individual and combined diuretic effects of four Vietnamese traditional herbal remedies (Zea mays, Imperata cylindrica, Plantago major and Orthosiphon stamineus).

Herbal remedies are widely used in Vietnam alongside modern drugs. We assessed the diuretic effect of four traditional Vietnamese herbal remedies from Zea mays, Imperata cylindrica, Plantago major and Orthosiphon stamineus, all claimed to produce an increase of diuresis. No influence was recorded for the 12- and 24-h urine output or on the sodium excretion for any of the drugs when tested under standardized conditions in a placebo controlled double-blind crossover model. The present study indicates the need for critical review of the present recommendations regarding therapy with plant materials in countries relying on empiric traditions.

Adult↗