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Biomedical subjects

F Nguyen

Publications and source records attributed to F Nguyen.

At least 19 recordsLinked to original sources
PubMed1998

Strategies for reaching Asian Americans with health information.

INTRODUCTION: Cultural, linguistic, and economic barriers place many Asian Americans in jeopardy of missing opportunities for disease prevention, early diagnosis, prompt treatment, and participation in clinical trials. One way to learn how to address these barriers is through the development of a demonstration health education and prevention program focused on an indicator disease such as cancer. METHODS: In 1994, the University of California, San Diego (UCSD) Cancer Center began a highly focused cancer education program. Staffing was done with a variety of bicultural and bilingual undergraduates recruited from local colleges and trained to work as community health educators. Asian grocery stores were selected as optimal educational sites. Adaptation of sheltered English teaching techniques and hands-on teaching aids helped to overcome language and educational barriers. The educational intervention was evaluated using unobtrusive measures. RESULTS: With the volunteers' help, culturally sensitive means to disseminate information on cancer were evaluated. A variety of approaches evolved that effectively bridged many communication barriers. Fear of cancer itself, belief that thinking about cancer could provoke the onset of the disease, and financial barriers to care proved to be just as formidable barriers to cancer education in this ethnic group as they are in others. Using student volunteers and donated store space, this educational program was conducted with minimal expense. CONCLUSION: Reaching this population with the help of ethnically and linguistically compatible students was effective, but the barriers they faced when trying to connect with their potential audience were still considerable. Rigorous evaluation of the strategies used in this intervention is warranted.

Asian↗
PubMed1998

Erythrocyte hyperaggregation and thrombogenic dysfibrinogenemia.

Erythrocyte aggregation was measured in 12 patients with congenital dysfibrinogenemia. The results showed hyperaggregation in four patients who had presented a thrombotic disorder, while aggregation was entirely normal in patients with asymptomatic dysfibrinogenemia. None of the four symptomatic patients had any other anomaly of hemostasis, in particular no coagulation inhibitor deficit or anti-phospholipid antibodies. The possible involvement of erythrocyte hyperaggregation in the thrombotic process is discussed.

Adult↗
PubMed1996

An antisense oligonucleotide to the notch ligand jagged enhances fibroblast growth factor-induced angiogenesis in vitro.

Angiogenesis, or the formation of new blood vessels, plays a central role in a number of physiologic and pathologic conditions, including wound healing, diabetic retinopathy, and solid tumor growth, and endothelial cells can be induced to mimic this process in vitro. Using a modification of the differential display method (Zimrin, A. B., Villeponteau, B., and Maciag, T. (1995) Biochem. Biophys. Res. Commun. 213, 630-638), we isolated the human homolog of the Jagged ligand for the Notch receptor from human endothelial cells exposed to fibrin and demonstrate that the Jagged transcript, but not the Notch 1 or Notch 2 transcripts, are up-regulated by fibrin. Interestingly, the addition of an antisense Jagged oligomer to bovine microvascular endothelial cells grown on a collagen gel resulted in a marked increase in invasion and tube formation in the underlying gel in response to fibroblast growth factor. In contrast, no effect was observed on vascular endothelial growth factor-induced angiogenesis under identical conditions. These data suggest that Jagged-Notch signaling is able to regulate fibroblast growth factor-induced endothelial cell migration in vitro, an early event during angiogenesis in vivo.

Calcium-Binding Proteins↗
PubMed1996

A data management software for the Sysmex NE 8000 haematology analyser.

The Sysmex NE 8000 (TOA-Japan) is a haematology analyser that performs blood cells count and leukocyte differential count. For facilitating the work of technical validation, we developed a software adapted to any IBM or compatible PC running under MS-DOS, to manage the analyser. Data are automatically collected via the RS-232 interface from the analyser or keyed in for the other techniques. The software deals with 64 different analyses entirely "user defined". Six technical alarms of the analyser are taken in account for red or white cells and platelets. An "electronic worksheet" presents the results or alarms with 10 patients to a page. This enables the lab technician to assess the coherence of the various data and to perform verifications or complementary tests if necessary. As an option, a blinking asterisk can signal any results out of predetermined range. By moving the cursor through the table, a test result can be deleted, modified or added. A function displays the patient previous files in a window because the data are recorded in long term archives at the end of the day. This long term recording allows a search of previous files to decide additional tests if the patient is unknown. If the patient is known, with additional tests previously performed, this procedure is time saving. A daily archive function classifies and prints the whole day's work in alphabetical order. A protocol of communication allows a connection to a mainframe computer Bayer-Technicon. This program and the user's manual are free of charge, available on request from J. P. Cambus.

Blood Cell Count↗
PubMed1996

Predicting daily maintenance dose of fluindione, an oral anticoagulant drug.

Due to large inter-individual variations, the dose of vitamin K antagonist required to target the desired hypocoagulability is hardly predictible for a given patient, and the time needed to reach therapeutic equilibrium may be excessively long. This work reports on a simple method for predicting the daily maintenance dose of fluindione after the third intake. In a first step, 37 patients were delivered 20 mg of fluindione once a day, at 6 p.m. for 3 consecutive days. On the morning of the 4th day an INR was performed. During the following days the dose was adjusted to target an INR between 2 and 3. There was a good correlation (r = 0.83, p < 0.001) between the INR performed on the morning of day 4 and the daily maintenance dose determined later by successive approximations. This allowed us to write a decisional algorithm to predict the effective maintenance dose of fluindione from the INR performed on day 4. The usefulness and the safety of this approach was tested in a second prospective study on 46 patients receiving fluindione according to the same initial scheme. The predicted dose was compared to the effective dose soon after having reached the equilibrium, then 30 and 90 days after. To within 5 mg (one quarter of a tablet), the predicted dose was the effective dose in 98%, 86% and 81% of the patients at the 3 times respectively. The mean time needed to reach the therapeutic equilibrium was reduced from 13 days in the first study to 6 days in the second study. No hemorrhagic complication occurred. Thus the strategy formerly developed to predict the daily maintenance dose of warfarin from the prothrombin time ratio or the thrombotest performed 3 days after starting the treatment may also be applied to fluindione and the INR measurement.

Administration, Oral↗
PubMed1996

D-dimer test and diagnosis of deep vein thrombosis: a comparative study of 7 assays.

The current D-Dimer ELISA methods provide high sensitivity and negative predictive value for the diagnosis of deep vein thrombosis but these methods are not suitable for emergency or for individual determination. We have evaluated the performance of 3 newly available fast D-Dimer assays (Vidas D-Di, BioMérieux; Instant IA D-Di, Stago; Nycocard D-Dimer, Nycomed) in comparison with 3 classic ELISA methods (Stago, Organon, Behring) and a Latex agglutination technique (Stago). One-hundred-and-seventy-one patients suspected of presenting a first episode of deep vein thrombosis were investigated. A deep vein thrombosis was detected in 75 patients (43.8%) by ultrasonic duplex scanning of the lower limbs; in 11 of them the thrombi were distal and very limited in size (< 2 cm). We compared the performance of the tests by calculating their sensitivity, specificity, positive and negative predictive value for different cut-off levels and by calculating the area under ROC curves. The concordance of the different methods was evaluated by calculating the kappa coefficient. The performances of the 3 classic ELISA and of the Vidas D-Di were comparable and kappa coefficients indicated a good concordance between the results provided by these assays. Their sensitivity slightly declined for detection of the very small thrombi. Instant IA D-Di had a non-significantly lower sensitivity and negative predictive value than the 4 previous assays; however its performance was excellent for out-patients. As expected, the Latex assay had too low a sensitivity and negative predictive value to be recommended. In our hands, Nycocard D-Dimer also exhibited low sensitivity and negative predictive value, which were significantly improved when the plasma samples were tested by the manufacturer. Thus significant progress has been made, allowing clinical studies to be planned to compare the safety and cost-effectiveness of D-Dimer strategy to those of the conventional methods for the diagnosis of venous thrombosis.

Adolescent↗
PubMed1995

Synthesis and characterization of supramolecular biovector (SMBV) specifically designed for the entrapment of ionic molecules.

Supramolecular biovectors (SMBV) are nanoparticular drug carriers composed of an internal crosslinked solid core externally grafted with fatty acids and surrounded with a phospholipid layer. We show in this paper that the internal core can be derivatized with anionic ligands such as phosphate in order to allow the efficient entrapment of cationic molecules through a process akin to ion exchange. Synthesis of SMBV involved first a cross linking and derivatization step of polysaccharides followed by a homogenization, a drying and a regioselective acylation step. Acylated polysaccharide cores are thus obtained which can be loaded with drugs and wrapped with a phospholipid layer. The SMBVs obtained are characterized through their size, 20 nm, and their ability to filter through 0.22 microns pore size membrane. Gel permeation chromatography experiments performed with various phospholipid/acylated cores ratios indicate that SMBVs form entities distinct from liposomes and that the optimum phospholipid/acylated cores ratio for this specific type of SMBVs is close to 100%. The supramolecular structure of SMBVs and in particular the spatial proximity between acylated cores and phospholipids is demonstrated through resonance energy transfer experiments. The drug loading capability of SMBVs is illustrated by the preparation of gentamicin and doxorubicin loaded SMBV. The therapeutic potential of SMBVs is then discussed notably in the light of a possible biomimetism with low density lipoproteins (LDL).

Doxorubicin↗
PubMed1994

Computer program for connection and data management of an automated coagulation system: the KC 10.

In Europe, the KC 10, manufactured by Amelung Germany, is one of the instruments most commonly found in coagulation laboratories. For facilitating the work of technical validation, we wrote a software adapted to any IBM or compatible PC running under MS-DOS, to manage the analyser performance. Data are automatically collected via the BCD interface from the analyser or keyed in for the other techniques. The software deals with 64 different analyses entirely 'user defined'. An 'electronic worksheet' presents the results, by page of ten patients. This enables the laboratory technician to assess the coherence of the various data and to perform verifications or complementary tests if necessary. As an option, a blinking asterisk can signal all results outside predetermined range. By moving the cursor through the table, a test result can be deleted, modified or added. A function displays the patient's previous files in a window because the data are recorded in long-term archives at the end of the day. This long-term recording allows a search of previous files to decide additional tests if the patient is unknown. A daily archive function classifies and prints the whole day's work in alphabetical order. A protocol of communication allows connection to a mainframe Bayer-Technicon computer. This program and the user's manual are free, available on request from address above.

Blood Coagulation Tests↗
PubMed1994

A data management program for the Electra 800 automatic analyser.

The Electra 800 automatic coagulation analyser rapidly performs most chronometric coagulation tests with high precision. To facilitate data handling, software, adaptable to any PC running under MS-DOS, was written to manage the analyser. Data are automatically collected via the RS232 interface or can be manually input. The software can handle 64 different analyses, all entirely 'user defined'. An 'electronic worksheet' presents the results in pages of ten patients. This enables the operator to assess the data and to perform verifications or complementary tests if necessary. All results outside a predetermined range can be flagged and results can be deleted, modified or added. A patient's previous files can be recalled as the data are archived at the end of the day. A 120 Mb disk can store approximately 130,000 patient files. A daily archive function can print the day's work in alphabetical order. A communication protocol allows connection to a mainframe computer. This program and the user's manual are available on request, free of charge, from the authors.

Autoanalysis↗
PubMed1993

Heparin removal in three intraoperative blood savers in cardiac surgery.

The aim of the study was to compare the residual heparin in the composition of autologous blood retransfusion units harvested during cardiac surgery under extra-corporeal circulation with three different intraoperative autologous blood savers. In this institutionally approved study, thirty patients undergoing CABG were randomly assigned to three groups according to the intraoperative blood saver used during the procedure: {HAEMONETICS Cell Saver IV (n=10)--DIDECO/SHILEY STAT (n=11)--BRAT 250 (n=9)}. Anaesthesia and conduct of bypass were identical for all patients. The initial heparin dose was 300IU-kg -1 and was supplemented to maintain an activated coagulation time over 480s. The harvested blood was processed according to the procedure defined by each equipment manufacturer. The biological study was performed on the first blood sediments sampled before administering protamine to the patient. Blood cell count, residual heparinemia assessed by its anti-Xa activity using an amidolytic method {STACHROM HEPARIN--DIAGNOSTICA STAGO}, and weight of the blood sediment proteins were determined. Demographic data did not differ between groups. Despite a slight but significant difference between groups, the three devices provided virtual elimination of heparin. The total protein content was significantly higher in the BRAT 250 group. There was a highly significant positive correlation between the anti-Xa activity and total protein content. Haematologic data were within clinically acceptable ranges.

Adult↗
PubMed1983

Impairment of polymorphonuclear functions in hospitalized geriatric patients.

Polymorphonuclear (PMN) functions were assessed in 93 non-selected hospitalized patients, 32 active, healthy, elderly controls and 29 young controls. The results confirm the impairment of PMN functions in the aged. However, PMN functions in hospitalized older persons are similar to those in non-institutionalized controls, and underlying diseases and treatment do not seem to aggravate the PMN impairment. Thus, it can be assumed that the frequent and severe infections afflicting the hospitalized aged are due to the alteration of the other host-defense mechanisms.

Aged↗
PubMed1982

Malignant external otitis and polymorphonuclear leukocyte migration impairment. Improvement with ascorbic acid.

Malignant external otitis (MEO) is a rare disease due to a Pseudomonas infection of the external ear occurring in an elderly patient with uncontrolled diabetes mellitus. Its high mortality raises the question of an alteration of the defense mechanisms of the body. A 58-year-old man was affected with MEO, and after several months of unsuccessful treatment, a study of the function of his polymorphonuclear neutrophil leukocytes (PMNs) revealed a defect of the migration capability. Ascorbic acid (vitamin C) was proved in vitro to be able to improve the results of the migration test. The patient was treated for one month with ascorbic acid and, parallel to the normalization of the chemotaxis test results, the ear lesions healed. The mechanism of such an alteration of the PMN function, implying several factors (the active infection, old age, and diabetes mellitus), is still unclear. Nevertheless, it is certainly important to test the PMN function in patients with MEO and treat them with immunomodulators.

Ascorbic Acid↗
PubMed1982

Polymorphonuclear functions in Hodgkin's disease patients at diagnosis, in remission, and in relapse.

Five tests investigating different aspects of the nonspecific defense mechanisms including capillary tube random migration, particle ingestion activity, quantitative and histochemical nitroblue tetrazolium dye reduction by polymorphonuclear neutrophils, and serum lysozyme concentrations were performed in 46 patients with Hodgkin's disease. The anomalies observed in the active stage of the disease consisted of a decreased random migration, a high level of serum lysozyme, and an increased nitroblue tetrazolium reduction by resting phagocytes associated with a decrease in nitroblue tetrazolium reduction by stimulated phagocytes. The particle ingestion activity was normal. The serum lysozyme assay was the only test observed to normalize in the group of patients in remission. Its determination, therefore, offers an additional means of evaluating disease activity.

Adolescent↗
PubMed1980

Phagocytosis in myeloproliferative disorders.

The phagocytic function was investigated by means of four tests (capillary tube random migration, phagocytosis of yeast particles, quantitative nitroblue tetrazolium dye reduction and whole-blood bactericidal activity for Staphylococcus aureus) in 57 patients who had myeloproliferative disorders: 24 had chronic granulocytic leukemia, 22 had polycythemia vera, six had myelofibrosis, and five had essential thrombocythemia. This study confirms the previously reported functional anomalies of phagocytosis in all the myeloproliferative disorders and shows that, despite these anomalies, the increased number of phagocytes allows an efficient whole-blood bactericidal activity, essential for the nonspecific host defence mechanisms.

Blood Bactericidal Activity↗
PubMed1980

In vitro effect of tobacco smoke components on the functions of normal human polymorphonuclear leukocytes.

The function of polymorphonuclear leukocytes (PMNs) has previously been shown to be impaired in smokers in comparison with healthy nonsmokers. Potent inhibition of PMN chemotaxis has been achieved with whole tobacco smoke, the gas phase of smoke, and a water-soluble extract of whole smoke. In the present work several aspects of PMN function were studied after exposure to water-soluble fraction of the particle phase of tobacco smoke collected on glass fiber filters. These tests included capillary tube random migration, chemotaxis under agarose, phagocytosis of yeasts, Nitro Blue Tetrazolium dye reduction, and whole-blood bactericidal activity. The water extract of the particle fraction of smoke had a high content of nicotine when compared with the levels achieved in plasma of smokers and a much lower concentration of aldehydes when compared with the gas phase of smoke. It had no cytotoxic effect and did not affect phagocytosis, oxygen consumption, or bactericidal activity. Nitro Blue Tetrazolium reduction of both resting and stimulated PMNs was significantly decreased only with the most concentrated solution. The tested solutions exerted a dose-related depressive effect on capillary tube random migration, whereas the random migration measured in the agarose chemotaxis test was normal. Nevertheless, the chemotactic response to a caseine solution was significantly decreased. The same tests were performed in the presence of several concentrations of a nicotine solution and the only test to be affected was the capillary tube random migration, and, that only at a very high concentration. The results of this study contribute to the more precise delineation of the extent of the dysfunction of PMNs exposed to tobacco smoke components and indicate that deleterious products are released from the particle phase of the smoke, which deposits all along the respiratory tree.

Adult↗
PubMed1979

Effect of tobacco smoking on the functions of polymorphonuclear leukocytes.

Eight tests investigating the function of circulating polymorphonuclear leukocytes were performed in 68 subjects, half of whom smoked at least 20 cigarettes per day. Comparison of the two groups allowed determination of the in vivo effect of tobacco smoke on the nonspecific defense system of the body. Ingestion ability, oxygen consumption, and bactericidal activity were normal in smokers. Myeloperoxidase and neutrophil alkaline phosphatase activities also were unchanged. The nitroblue tetrazolium reduction and the serum lysozyme levels were slightly increased in smokers. The capillary tube random migration, though, was depressed, and intensive smoking further aggravated this change. It is suggested that tobacco smoke acts directly on one (or several) unidentified target site of polymorphonuclear leukocytes. This impairment, demonstrated in vivo, probably plays a role in the genesis of the bronchopulmonary diseases so frequent in heavy smokers.

Alkaline Phosphatase↗