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Biomedical subjects

D T Nguyen

Publications and source records attributed to D T Nguyen.

At least 19 recordsLinked to original sources
PubMed1999

Effect of diabetes and aminoguanidine therapy on renal advanced glycation end-product binding.

BACKGROUND: Advanced glycation end-products (AGEs) have been implicated in the pathogenesis of diabetic nephropathy, and aminoguanidine (AG) has been shown to decrease the accumulation of AGEs in the diabetic kidney. METHODS: This study investigates changes in AGE binding associated with diabetes in the rat kidney using in vitro and in vivo autoradiographic techniques. Male Sprague-Dawley rats were randomized into control and diabetic groups with and without AG treatment and were sacrificed after three weeks. Frozen kidney sections (20 microm) were incubated with [125I]-AGE-RNase or [125I]-AGE-BSA. To localize the AGE binding site, in vivo autoradiography was performed by injection of 15 microCi of [125I]-AGE-BSA into the abdominal aorta of the rat. RESULTS: Low-affinity binding sites specific for AGEs in the renal cortex (IC50 = 0.28 microm) were detected by in vitro autoradiography. There was a significant increase in [125I]-AGE binding in the diabetic kidney, which was prevented by AG treatment. Emulsion autoradiography revealed that binding was localized primarily to proximal tubules in the renal cortex. Renal AGE levels, as assessed by fluorescence or by radioimmunoassay, were increased after three weeks of diabetes. This increase was attenuated by AG therapy. CONCLUSIONS: AGE binding sites are present within the proximal tubules of the kidney and appear to be modulated by endogenous AGE levels. It remains to be determined if these binding sites represent receptors involved in clearance of AGEs or are linked to pathogenic pathways that lead to the development of diabetic nephropathy.

Animals↗
PubMed1999

IDEC-C2B8 anti-CD20 (rituximab) immunotherapy in patients with low-grade non-Hodgkin's lymphoma and lymphoproliferative disorders: evaluation of response on 48 patients.

This study focused on the efficacy of IDEC-C2B8 (chimeric anti-CD20) immunotherapy relative to specific subtypes of low-grade lymphoproliferative disorders/non-Hodgkin's lymphomas (LPD/NHL). Forty-eight patients with resistant or relapsed disease completed the IDEC-C2B8 infusion schedule of 375 mg/m2/wk x 4 wk. The LPD/NHL subtypes included: (a) follicular centre cell lymphoma (FCC) in 22 patients; (b) mantle cell lymphoma (MCL) in 10; (c) 1 diffuse large cell lymphoma (DLCL); and (d) the category of small lymphocytic lymphoma/chronic lymphocytic leukaemia (SLL/CLL) and related disorders in 15 patients. No patient obtained a complete remission. Ten patients (21%) achieved partial remission: 6 FCC, 2 MCL, 1 DLCL and 1 patient from the SLL/CLL group. Twenty-eight patients had stable disease and 10 progressed during immunotherapy. In patients with CLL and MCL in leukaemic phase, there was no correlation between the marked decrease in circulating neoplastic cells following antibody infusions and amelioration of the tumour burden. The results suggest that the subtype of LPD/NHL and the intensity of CD20 on the tumour cells influence the effectiveness of IDEC-C2B8. The antibody was most efficacious against FCC lymphoma. The efficacy (at the dose schedule of 375 mg/m2/wk x 4) against MCL and SLL/CLL appeared to be limited, however.

Adult↗
PubMed1999

Response to interferon alpha treatment and disappearance of cryoglobulinaemia in patients infected by hepatitis C virus.

BACKGROUND: Mixed cryoglobulinaemia is closely associated with hepatitis C virus (HCV) infection. AIM: To assess in a prospective open study the efficiency of interferon alpha treatment of cryoglobulinaemia, as reflected by the disappearance of cryoglobulins and clinical manifestations of the disease, and to analyse the factors predictive of a response to interferon. METHOD: Eighty seven consecutive patients with chronic hepatitis C treated for the first time with interferon at a dose of 3 x 10(6) international units three times a week for six months were studied. Forty three patients had cryoglobulins, which were responsible for clinical manifestations in 12. RESULTS: At the end of interferon treatment, cryoglobulins had disappeared in 39% of the patients. A clinical improvement (except for neuropathies) was observed in all patients. Six months after interferon treatment was stopped, the same rate of response (normal alanine aminotransferase values and undectable HCV RNA) was observed in patients with or without cryoglobulins. Only 14% of patients still had undetectable cryoglobulins, and all of them also had undetectable serum HCV RNA. The disappearance of cryoglobulins was found less frequently in patients with clinical symptoms than in asymptomatic ones, but the difference was not significant. Sustained responders were more often men, infected by genotype 2 or 3, with a lower pretreatment viral load. CONCLUSION: The presence of cryoglobulins does not seem to affect the response to interferon in HCV infected patients. The improvement in cryoglobulinaemia is strongly associated with a virological response, reinforcing the hypothesis of a direct role for HCV in the pathogenesis of this disease.

Adult↗
PubMed1999

Descriptive epidemiological survey on a given day in all palliative care patients hospitalized in a French university hospital.

We conducted a descriptive study on a given day on all inpatients requiring palliative care in a French university hospital. In each department, a collaborative team made up of physicians and nurses identified and described the clinical signs, the treatment protocols, the social and family characteristics and the outcome for each patient using a standardized questionnaire. Study subjects were inpatients in the hospital and presented advanced or terminal-stage life-threatening conditions. Two-hundred-and-forty-five patients were included in the study. These patients represented 13% of the total number of inpatient beds available in the hospital on the day of the survey. Sixty-six per cent of study subjects suffered from physical discomfort and 80% suffered psychologically. Patients still received specific treatment for their condition in 45% of cases. Social problems were identified principally in medium- or long-term care department inpatients who made up 36% of the total inpatient population. A request for transfer to another care structure had been completed for 24% of patients. Assistance from the Palliative Care Unit's support team had been requested in 25% of cases, mainly to provide psychological support for the patient and the health care providers. These results have led us to reconsider the general organization of palliative care in the health care system.

France↗
PubMed1998

A review of the present status of lymphatic filariasis in Vietnam.

Establishing the current status of an infectious disease forms the starting point of any attempt at parasite control. Although data on the prevalence and distribution of lymphatic filariasis exist for Vietnam from the early 1900s, the present situation regarding the disease is less well-known. Here, we review the results of recent surveys conducted by the Institute of Malariology, Parasitology and Entomology, Hanoi, to update the existing information on filariasis epidemiology and distribution for this country. The present results are from surveys carried out on some 135,000 individuals in 24 provinces of Vietnam. The highest prevalences of microfilaraemia (primarily Brugia malayi ) are observed in lowland areas of the Red River Delta and in Quang-binh Province where the survey results show microfilaraemia (mf) prevalences in the range of 0.9-5.5%. The most common type of chronic clinical manifestation is shown to be leg elephantiasis. A significant finding is that an overall decrease in mf prevalence was observed to occur in five communities which were surveyed twice over an 11-21-year period, even though no interventions were carried out between the two surveys. The changes are probably caused by environmental changes, such as increased standards of housing and drainage. Studies on the effect of selective chemotherapy and mass chemotherapy using diethylcarbamazine showed reductions in community mf prevalences of 69 and 72-88%, respectively. Furthermore, cats do not appear to represent significant reservoirs of infection. These findings of geographical restriction of infection, effective and well-tolerated drug therapy, low significance of animal reservoirs, together with the existence of an effective national health network, suggest a good prognosis for the control of filariasis in this country.

Animals↗
PubMed1998

Evaluation of the injured wrist on the field and in the office.

The wrist is a common site of injury in sports, both acute and chronic. Evaluation of wrist injuries requires knowledge of anatomy kinematics, attention to the mechanism of injury, the intensity of training, and a focus on the physical examination for specific injuries.

Athletic Injuries↗
PubMed1998

Anesthetic management of the patient undergoing head and neck cancer surgery.

The head and neck cancer patient should be in the best possible medical condition before facing surgery, bearing in mind the status of the tumor and the urgency of the procedure. Careful assessment of the patient's upper airway will enable the anesthesiologist to select an appropriate course of action to secure the airway before the operation begins. In many cases, the patient can be safely intubated after the induction of general anesthesia. In other situations, the patient may require an examination of the airway while awake with the aid of sedation and topical analgesia to determine the safest intubation technique. If the patient has evidence of a difficult airway, a flexible fiberoptic-guided intubation may be indicated to secure the airway in the awake patient patient before general anesthesia is induced. Some patients with severe airway obstruction or large, bulky supraglottic tumors usually undergo an initial tracheostomy with local anesthesia to secure the airway. Following surgery, extubation of the patient's trachea requires careful attention and may have to be performed over a jet-ventilating stylet.

Airway Obstruction↗
PubMed1997

Simulation of the enzyme reaction mechanism of malate dehydrogenase.

A hybrid numerical method, which employs molecular mechanics to describe the bulk of the solvent-protein matrix and a semiempirical quantum-mechanical treatment for atoms near the reactive site, was utilized to simulate the minimum energy surface and reaction pathway for the interconversion of malate and oxaloacetate catalyzed by the enzyme malate dehydrogenase (MDH). A reaction mechanism for proton and hydride transfers associated with MDH and cofactor nicotinamide adenine dinucleotide (NAD) is deduced from the topology of the calculated energy surface. The proposed mechanism consists of (1) a sequential reaction with proton transfer preceding hydride transfer (malate to oxaloacetate direction), (2) the existence of two transition states with energy barriers of approximately 7 and 15 kcal/mol for the proton and hydride transfers, respectively, and (3) reactant (malate) and product (oxaloacetate) states that are nearly isoenergetic. Simulation analysis of the calculated energy profile shows that solvent effects due to the protein matrix dramatically alter the intrinsic reactivity of the functional groups involved in the MDH reaction, resulting in energetics similar to that found in aqueous solution. An energy decomposition analysis indicates that specific MDH residues (Arg-81, Arg-87, Asn-119, Asp-150, and Arg-153) in the vicinity of the substrate make significant energetic contributions to the stabilization of proton transfer and destabilization of hydride transfer. This suggests that these amino acids play an important role in the catalytic properties of MDH.

Binding Sites↗
PubMed1997

Fast separation of underivatized carbohydrates by coelectroosmotic capillary electrophoresis.

A method for the rapid quantitative analysis of underivatized acidic sugars, monosaccharides and disaccharides using coelectroosmotic capillary electrophoresis was developed. Indirect UV detection at 254 nm using sorbate as background electrolyte was employed for monitoring the analytes. A highly alkaline pH value of the electrolyte system was chosen in order to achieve an electrophoretic mobility of the saccharides towards the anode. A dynamic reversal of the electroosmotic flow and, by this means, a codirectional movement of the negatively charged analytes and the electroosmotic flow is accomplished by employing a polycationic surfactant (hexadimethrine bromide), which is added to the background electrolyte. To further improve the resolution of specific carbohydrates, acetone is used as organic modifier. A practical application of the developed method for the fast determination of fructose, glucose, and sucrose in various soft drinks is provided.

Acetone↗
PubMed1997

A comprehensive knowledge-based system for laboratory hematology.

The Coulter FACULTY knowledge-based systems, Professor Petrushka for peripheral blood interpretation, Professor Fidelio for flow cytometry immunophenotyping and Professor Belmonte for bone marrow reporting, have been installed in several hospitals in Spain, Portugal and the United Kingdom. In Spain and Portugal, the systems are part of the IZASA-Coulter CITOTECA workstation, which includes a video camera for capturing microscopic images and a networkable laboratory information system supporting color reports. At the Royal Hospitals Trust (St. Bartholomew's Hospital and The Royal London Hospital, London, UK), networked workstations are available and the system is used daily to generate bone marrow reports in the hematology laboratories. There have been considerable benefits from adopting Coulter FACULTY for bone marrow reporting, including faster turnaround time, improved quality of the reports and cost savings.

Artificial Intelligence↗
PubMed1997

Haematological validation of a computer-based bone marrow reporting system.

AIMS: To prove the safety and effectiveness of "Professor Belmonte", a knowledge-based system for bone marrow reporting, a formal evaluation of the reports generated by the system was performed. METHODS: Three haematologists (a consultant, a senior registrar, and a junior registrar), none of whom were involved in the development of the software, compared the unedited reports generated by Professor Belmonte with the original bone marrow reports in 785 unselected cases. Each haematologist independently graded the quality of Belmonte's reports using one of four categories: (a) better than the original report (more informative, containing useful information missing in the original report); (b) equivalent to the original report; (c) satisfactory, but missing information that should have been included; and (d) unsatisfactory. RESULTS: The consultant graded 64 reports as more informative than the original, 687 as equivalent to the original, 32 as satisfactory, and two as unsatisfactory. The senior registrar considered 29 reports to be better than the original, 739 to be equivalent to the original, 15 to be satisfactory, and two to be unsatisfactory. The junior registrar found that 88 reports were better than the original, 681 were equivalent to the original, 14 were satisfactory, and two were unsatisfactory. Each judge found two different reports to be unsatisfactory according to their criteria. All 785 reports generated by the computer system received at least two scores of satisfactory or better. CONCLUSIONS: In this representative study, Professor Belmonte generated bone marrow reports that proved to be as accurate as the original reports in a large university hospital. The haematology knowledge contained within the system, the reasoning process, and the function of the software are safe and effective for assisting haematologists in generating high quality bone marrow reports.

Bone Marrow↗
PubMed1997

[Access to health care for destitute persons at Public Assistance Hospitals in Paris].

All legal French residents are entitled to health care. The 1992 regulatory measures, which create a contractual agreement between the government and public medical institutions, aim at facilitating access to health care by resolving the financial obstacles to accessing health care. The Assistance Publique-Hôpitaux de Paris (AP-HP) has set up a medical reception center in several hospitals since 1993. This system is integrated in the general structure of each hospital: in some cases, there is a single and centralized unit; in other cases, all departments of the hospital, including the emergency room, are involved in caring for destitute patients. Whatever the type of the structure may be, social workers are a key element to helping the patients recover their social rights. Thirty to seventy-percent of patients visiting these centers regain access to social and health care coverage. The epidemiological survey of the active file of patients revealed that 70% are male, more than 50% are non-French nationals, half of which do not have legal immigration status in France. Homeless people represent 40 to 80% of the population. The average age is around 35. The number of medical visits varies greatly from one hospital to another and range from 20 to 60 per month. The reasons for visiting the center and the identified medical disorders are strongly related to the patients' life conditions and vary significantly with the risk factors related to the social and economic situation. The frequency of some diseases (psychiatric disorders, tuberculosis, infections by the HIV and HCV) is higher in this population than in general population. Delayed visits to the medical center represents a severity factor. The hospitals' mission statement is not only to ensure that patients facing a precarious social and professional situation have equal access to health care, but also to help such patients recover their social rights, facilitate their integration in the society and fight against social exclusion.

Health Services Accessibility↗
PubMed1996

Effects of earplugs on catecholamine and cortisol excretion in noise-exposed textile workers.

To investigate physiological and psychological effects of industrial noise, a survey was performed on 50 female workers exposed to machinery noise [93-100 dB(A)] (noise group) and 25 female workers in less-noisy environments [71-75 dB(A)] (control group) in a textile factory in Vietnam. Urine was collected for analysis of catecholamines and cortisol. The subjects were also asked to fill out a questionnaire. Each subject was examined over 2 working days. The workers in the noise group were asked to put earplugs in their ears during the working hours of the 2nd day. On the 1st day without earplugs, urinary excretion of catecholamines in the noise group were greater than those in the control group. Cortisol in urine showed a similar tendency. Differences in catecholamine excretion between the noise group and the control group decreased on the 2nd day when the earplugs were used for attenuation of noise level in the noise group. Frequency of subjective fatigue symptoms was lower on the 2nd day than that on the 1st day in noise group, while the control group showed almost no day-difference. The results indicate that the catecholamine response to noise in workers was reduced through the use of earplugs.

Adult↗
PubMed1996

Differential diagnosis of L26-positive, CD15-negative Hodgkin's disease and large B-cell lymphoma with a high content of reactive T-cells: a morphologic and immunohistochemical study.

B-cell non-Hodgkin's lymphomas with a marked preponderance of reactive T cells, so-called T-cell rich B-cell lymphomas (TCRBCLs), can be morphologically confused with Hodgkin's disease (HD). To establish helpful distinguishing features in paraffin sections, 10 cases of L26-positive, CD15-negative HD and 10 cases of TCRBCL were compared; 4 cases of HD had morphologic features of the nodular lymphocyte predominant (LP) type. Nine of 10 cases of HD contained fewer than 20 mitoses/20 high power fields (hpf) and only 1 had pericapsular involvement. In contrast, 9 of 10 TCRBCL had greater than 20 mitoses/20 hpf and 7 had perinodal infiltration. HDLP was easily distinguished from TCRBCL by the expanded dendritic meshworks outlining the L & H nodules and the high content of CD57-positive lymphocytes. The remaining 6 cases of non-LP L26-positive HD had a relatively distinctive immunostaining pattern, with absence of CD45 and discordant reactivity for L26 and Ki-B5 in Reed-Sternberg cells and variants. Only 3 cases of TCRBCL had a similar CD45 and L26/Ki-B5 immunostaining pattern, and these could be distinguished by demonstrable cytoplasmic light-chain restriction. These results show that evaluation of the mitotic count, pericapsular involvement, and immunohistochemical staining patterns for Ki-M4p, CD57, L26/Ki-B5, and CD45 can help to discriminate TCRBCL from L26-positive HD when only fixed material is available.

Adult↗
PubMed1995

Chronic lymphocytic leukemia with an interfollicular architecture: avoiding diagnostic confusion with monocytoid B-cell lymphoma.

Certain low grade B-cell lymphoproliferative disorders can be mistaken for each other morphologically, particularly when there is partial lymph node involvement. We encountered two cases of chronic lymphocytic leukemia, in which the interfollicular growth pattern and the pale appearance of the neoplastic proliferation in the lymph nodes led to a misclassification as monocytoid B-cell lymphoma. The correct diagnosis was established, however, when the lymph node morphology was carefully reexamined, with the knowledge of the clinical history, peripheral blood findings, and bone marrow data. The immunophenotype of the neoplastic cells in the peripheral blood (CD5, CD23, weak fluorescence intensity of surface immunoglobulin and CD22) and the lymph node immunohistochemistry (weak L26 staining, strong MT1 positivity) confirmed the diagnosis of chronic lymphocytic leukemia. These two cases demonstrate the necessity of a systematic approach to lymph node morphology and the utility of a multiparameter approach in the diagnosis of lymphoproliferative disorders.

Aged↗