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Biomedical subjects

S Nguyen

Publications and source records attributed to S Nguyen.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Signal processing in electromyography: a review].

Automatic analysis of electromyography (EMG), signals, first operated in 1950 with analogic machines, steeply expanded from 1980 when fast computers and worthwhile programs became available. On-line measurement of response area and latency, averaging of low amplitude waves, fast sorting of motor unit potential shape parameters, computation of the "jitter" between two muscle fibers, turns/amplitude and spectral analysis of interferential pattern records, are some examples of programs currently offered in modern EMG machines. Other techniques are still reserved for research purposes: scanning EMG, decomposition of nerve and muscle compound potentials, measurement of the threshold and firing rate of motor units, trace analysis using tracking models. Finally, the credit for artificial intelligence systems (knowledge based systems, fuzzy logic, neuronal networks) is still not clearly stated.

Artifacts↗
PubMed1996

Genotyping Procedures in Linkage Mapping

Genotyping methods based on nonradioactive detection of PCR products and suitable for large-scale mapping projects are described. Two alternative techniques are proposed for the genotyping of polymorphic short tandem repeats or microsatellite markers. The first is designed for investigators who do not have access to automatic sequencing machines. This technique uses multiplex analysis of PCR products that are separated on sequencing gels, transferred to nylon membranes, and detected by hybridization with nonradioactive probes. The second technique uses automatic sequencing machines for the detection of fluorescently labeled PCR products. Another method describes the analysis of nonpolymorphic markers in whole-genome radiation hybrids. This method uses separation and detection of PCR products on agarose gels.

Journal Article↗
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↗
PubMed1995

Autosomal recessive lamellar ichthyosis: identification of a new mutation in transglutaminase 1 and evidence for genetic heterogeneity.

Autosomal recessive lamellar ichthyosis (ARLI) belongs to the group of congenital disorders of cornification. It is characterized by a severe and generalized ichthyosis, and other variable cutaneous signs. The human transglutaminase 1 (TGM1) gene was recently found to be the disease-causing gene. Linkage analysis in 23 families (of which 13 were consanguineous) showed that for 10 of them, the disease was linked to the TGM1 gene. A new deleterious mutation introducing a stop codon in the TGM1 reading frame was found. Nevertheless, for the 13 other ARLI families, TGM1 was found to be unlinked to the disease. The present data show that ARLI is genetically heterogeneous and confirm that TGM1 is one of the responsible genes.

Base Sequence↗
PubMed1995

Mechanism of sodium nitroprusside-mediated inhibition of aromatic amino acid decarboxylase activity.

The effects of sodium nitroprusside (SNP) on dopamine synthesis in a porcine renal epithelial cell line (LLC-PK1) were evaluated. Subsequent studies examined the actions of the degradation products of SNP (cyanide, ferrous ion and nitric oxide) on aromatic amino acid decarboxylase (AAAD) activity in tissue supernatants from LLC-PK1 cells and rat renal cortex. SNP (10-500 mumol/l) significantly inhibited dopamine production in LLC-PK1 cells in a dose-related manner. The activation of guanylate cyclase by nitric oxide was not found to be the mechanism whereby SNP inhibited dopamine synthesis in LLC-PK1 nor did the antioxidant glutathione attenuate the actions of SNP. Ferrous sulfate (0.5 mmol/l) and SNP (0.5 mmol/l) were found to inhibit dopamine synthesis in LLC-PK1 cells and to directly inhibit cytosolic AAAD activity from LLC-PK1 cells. A series of studies were conducted using AAAD from rat renal cortex and confirmed that SNP could directly inhibit the conversion of L-dopa to dopamine by AAAD. Furthermore, potassium ferricyanide (1 mmol/l) and potassium cyanide (1 mmol/l) could produce greater than 80% reductions in AAAD activity. Iron (0.5-1 mmol/l) was found to increase rat kidney AAAD activity. Kinetic analysis revealed that potassium cyanide was a potent (Ki = 40-50 mumol/l) noncompetitive/mixed noncompetitive inhibitor of AAAD. SNP was also found to be a noncompetitive inhibitor of AAAD with a Ki of approximately 300-500 mumol/l. In contrast, ferrous sulfate (0.5 mmol/l) was a competitive inhibitor (Ki = approximately 650 mumol/l) that actually increased the Vmax of AAAD. The results of these studies support that cyanide released from SNP can potently inhibit AAAD, although SNP has somewhat more complex interactions with AAAD due to the presence of ferrous ion.

Animals↗
PubMed1994

Ethmoid sinus carcinomas: results and prognosis after neoadjuvant chemotherapy and combined surgery--a 10-year experience.

From June 1982 to June 1992, 144 ethmoido-sphenoido-orbital tumors have been referred to the neurosurgical department of Ste Anne Hospital. One hundred five of them were malignant lesions, among which 83 were included into our therapeutic protocol (1) neo-adjuvant chemotherapy (CDDP + 5-FU), (2) combined surgical procedure (subfrontal and transfacial), (3) postoperative radiotherapy. Fifty nine percent of the patients had no response to chemotherapy; 19% had a partial response (reduction of the tumoral volume > 50% and < 100%), 22% had a complete response. One patient had an immediate and transient postoperative rhinorrhea responsible for meningitis (acinetobacter) that was cured after a 3-day treatment. Four patients had postoperative meningitis without any cerebrospinal fluid leakage; they were also cured. Five patients had a local suppuration that was treated by subcutaneous drainage (n = 1) or the removal of the cranial basis graft (n = 4). Oncologic results are presented for only adenocarcinomas (n = 63) because they represent the only population of this series large enough to assure significant statistical figures. The global actuarial survival rate was 53% at 3 years and 42.5% at 5 years. The 5-year actuarial survival rate was 80% for T1 tumors, 60% for T2, 40% for T3, and 25% for T4. Patients with an intracranial extension had a 3-year survival rate of 19%; none survived after 4-year follow-up. Neo-adjuvant chemotherapy seemed to influence the survival: 100% survival rate at 5 and 10 years for the complete responders. We discuss the opportunity of intraorbital exenteration, the indications, and the limits of combined surgery. We emphasize the importance of neo-adjuvant chemotherapy and of combined surgical procedures, even when the patients are complete responders to chemotherapy: complete responders who had only a transfacial approach have a 5-year actuarial survival rate of 80% (instead of 100% when a combined procedure was performed). Those who were not operated primarily recurred within 3 years and then had to be operated. We propose to follow such a combined surgery for all large ethmoidal cancers (T3 and T4) and for small tumors (T1 and T2) developed superiorly and posteriorly. Anterior T1 and T2 tumors should be operated through a single transfacial route.

Actuarial Analysis↗
PubMed1993

Long-term safety and efficacy of programmable implantable insulin delivery systems.

OBJECTIVES: Since only short-term studies of continuous intraperitoneal insulin infusion (CIPII) therapy using implantable programmable insulin delivery systems have been performed to show this method of diabetes therapy to be safe and efficacious, we have performed long-term studies to assess its safety and efficacy. RESEARCH DESIGN AND METHODS: For 78 patient-years of follow-up, we have longitudinally studied the incidence of diabetic ketoacidosis and severe hypoglycemia in 25 type 1 diabetic patients treated with CIPII. We also compared, cross-sectionally, the long-term safety and efficacy of CIPII to intensive subcutaneous insulin therapy using intermittent injections or continuous subcutaneous insulin infusion. Finally, we examined the relationship between glycated hemoglobin levels and the standard deviation of daily blood glucose excursion. RESULTS: Cross-sectional analysis revealed similar degrees of metabolic control accompanied by significantly decreased rates of both ketoacidosis (0.013 events/patient/year) and severe hypoglycemia (0.05 events/patient/year) during CIPII compared to intermittent injections and continuous subcutaneous insulin infusion therapy. A four-fold decrease in the rate of severe hypoglycemia was observed during longitudinal comparison of pre- and post-implantation complication rates. A relationship was also shown between decreased levels of mean glycated hemoglobin and the standard deviation of blood glucose excursions during CIPII therapy. CONCLUSIONS: Our data demonstrate that long-term therapy with CIPII is as effective as other methods in achieving near-normal levels of glycated hemoglobin, which in CIPII is associated with a decreased standard deviation of blood glucose excursions. Further, CIPII using implantable programmable insulin delivery systems is the safest method described for intensive insulin therapy in home blood glucose monitoring type 1 diabetic patients.

Adolescent↗
PubMed1992

[Evaluation and treatment of chronic pain after cervicofacial cancer surgery].

When lasting pain occurs after surgery of head and neck cancer, tumoral recurrence should be considered. In addition to curative treatment, relief of pain is often provided by opioid analgesics. Doses vary according to tolerance and patient. Other than digestive routes of administration may be required. Here are two clinical reports: the first case with cervical epidural analgesia by ambulatory autoadministration device (Patient control analgesia), the other one with intrathecal in C7-T1 catheter with port access in which morphine was injected every 24 hours resulting in efficient analgesia, in metastatic Pancoast's syndrome. Surgical or radiotherapy sequelae sometimes bring about pain; bilateral cervicalgy described as burns associated with pain-related depression, 18 months after glotto-subglottic partial laryngectomy, requires psychological support and carbamazepine for desafferation pain removed within 6 months. When the only treatment left appears to be analgesia after surgery of head and neck cancer, follow-up in a multidisciplinary pain treatment centre allows a therapeutical management with optimum tolerance and efficiency.

Adult↗
PubMed1991

Diagnosis of tuberculosis by DNA amplification in clinical practice evaluation.

Various polymerase chain reaction (PCR) assays have been devised for the rapid identification of mycobacteria in clinical specimens. To assess the value of such assays in routine laboratory work the results obtained by PCR were compared with those obtained by standard microbiological methods for 514 specimens collected for investigation of mycobacterial infection. Specimens were tested for the presence of Mycobacterium tuberculosis complex and atypical mycobacteria in two assays, one based on amplification of the 65 kDa gene and the other on the IS6110 insertion sequence. For the 489 samples that did not contain inhibitors of the amplification reaction PCR findings correlated well with bacteriological and/or clinical data in 476 (97.4%). 6 PCR results turned out to be false negatives, 3 to be false positives and 4 to be mis-identification of strains. Pre-treatment of samples with guanidium thiocyanate reduced the proportion of false-negative results and of samples that contained inhibitors. This study confirms the potential of DNA amplification for early diagnosis of mycobacterial infections.

DNA Probes↗
PubMed1990

The use of 1.32 Nd:YAG laser in neurosurgery: experimental data and clinical experience from 70 patients.

The authors present their experience with the 1.32 mum Nd:YAG laser in neurosurgical procedures. In a first step, they conducted experiments on rat cortex. The thermic data and histologic results confirmed that the 1.32 Nd:YAG laser has physical properties quite close to the CO2 laser. Furthermore, the fact that the 1.32 mum wavelength can be conducted through optic fibers makes it well adapted to neurosurgery. The authors present experimental data (50 rats) and comment on their surgical experience with such a wavelength (70 patients). In the future, this laser should see its indications broadened in conventional neurosurgical procedures as well as in endoscopic and stereotactic neurosurgery.

Animals↗
PubMed1990

Characterization of a Mycobacterium tuberculosis insertion sequence, IS6110, and its application in diagnosis.

An insertion sequence-like element, IS6110, was isolated from a Mycobacterium tuberculosis cosmid library as a repetitive sequence. IS6110 shows similarities with elements of the IS3 family. This insertion sequence was found to be specific to mycobacteria belonging to the M. tuberculosis complex. For detection and identification of M. tuberculosis bacilli in uncultured specimens, oligonucleotides derived from the IS6110 sequence were used as primers and probes in polymerase chain reaction studies. The results obtained were consistent with results of classical identification procedures, bacteriological data, and clinical criteria.

DNA Transposable Elements↗
PubMed1989

Adenocarcinoma of the ethmoid sinuses. Results of a new protocol based on inductive chemotherapy combined with surgery. Four years experience.

New therapeutic modalities for Ethmoidal Adenocarcinomas are presented. Thirty three patients harbouring such a tumour have been treated during the last four years. Twenty three were included in the following protocol:--the first step consisted in inductive chemotherapy based on a four-day course of continuous cisplatine (CDDP) and 5-fluoro-uracyl (5-FU infusion)--the second step was the tumour removal, which was performed through a combined transfacial and subfrontal approach. A contralateral ethmoidectomy was always performed. The integrity of the sphenoidal sinus was systematically checked. The cranial base was reconstructed with madreporic coral grafts; then a large extra-dural pediculated galea flap was placed onto the anterior base to line the sub-frontal dura. The authors discuss the results of this series of rare tumours.

Adenocarcinoma↗
PubMed1989

Computerized transcription of searches from MEDLINE to an information manager package, SCI-MATE.

MEDLINE bibliographic files, or searches from MEDLINE, can now be downloaded to personal computers. The materials can then be input to an information manager package, such as SCI-MATE, as a personal library for future updates, sorting, searching, cross-referencing, and reports. The transcription of the downloaded material to the manager package is tedious, however. A program has therefore been written to computerize the transcription.

Bibliography of Medicine↗
PubMed1988

Implementation of a home-based program for early detection of clinical deterioration in cystic fibrosis.

A statistical decision-making system, based on daily self measurements obtained at home, has been developed that will predict the clinical status of a patient with cystic fibrosis (CF). The data for the study were collected from patients randomly selected from those served by the University of Minnesota CF Center. Participants recorded four daily measurements (weight, vital capacity, breathing rate, and resting pulse) and one weekly measurement (height) and returned completed diaries to the coordinating center each week. The goal of the rule was to determine whether each patient's clinical status was deteriorating, remaining stable, or improving at the time of the most recent set of weekly measurements. This early detection and intervention criterion (EDIC) is being used in the clinical setting to aid in the management of patients with cystic fibrosis. The computer hardware and software, particularly the relational database, have provided an efficient basis for the continued use of EDIC.

Adolescent↗