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Biomedical subjects

J M Nguyen

Publications and source records attributed to J M Nguyen.

At least 19 recordsLinked to original sources
PubMed2006

[Analysis of reasons for the late diagnosis of amyotrophic lateral sclerosis].

INTRODUCTION: The mean diagnostic delay of amyotrophic lateral sclerosis (ALS) is greater than one year. Its causes are multiple, related to the affection, the patient, or medical practices. METHODS: An investigation was carried out in 77 consecutive patients, to describe their medical course since the date of the first symptoms until the diagnosis. Interrogation of the private practitioners potentially implied in the diagnostic procedure enabled an evaluation of the degree and origin of their knowledge of the disease. RESULTS: In the majority of patients, the first consultation was conducted by a general practitioner. Referral to a neurologist occurred on average 7 months after this consultation. A first-intention electrophysiological examination was prescribed in one-third of patients. Practitioners were unknowledgeable about certain clinical signs. Their knowledge on the disease came primarily from medical school training and for two-thirds, their satisfaction concerning their degree of training was low. CONCLUSION: This observational study shows that medical practices contribute to delayed diagnosis of ALS, particularly delayed referral to a neurologist. To enable earlier diagnosis, general practitioners should be informed of the usefulness of early referral for multidisciplinary care of patients.

Adult↗
PubMed2006

Inhalation induction using sevoflurane in children: the single-breath vital capacity technique compared to the tidal volume technique*.

The single-breath vital capacity technique is suitable for inhalation induction of anaesthesia, using sevoflurane in children aged > 5 years. The purpose of this randomised trial was to compare the single breath vital capacity technique with the conventional tidal volume technique. Seventy- three ASA 1 or 2 children were instructed during the pre-operative visit in the vital capacity technique. The main criterion measured was time to loss of the eyelash reflex. Induction was performed using a circle-absorber breathing circuit primed with sevoflurane 7% in 50% nitrous oxide/oxygen with 6 l.min(-1) fresh gas flow. Time required for induction, haemodynamic changes, airway tolerance and side-effects were recorded. The children's opinion on the technique used was scored using a visual analogue scale (0-100) and a Smiley scale (0-10). The time to loss of the eyelash reflex was found to be reduced in the vital capacity group compared to the tidal volume group. The time to central myosis, to achieve bispectral index values 60 and 40, haemodynamic changes, respiratory events and side-effect incidences were similar in both groups. However, we found that the vital capacity technique was preferred by the children to the tidal volume technique.

Anesthesia, Inhalation↗
PubMed2005

A simple method to optimize hospital beds capacity.

OBJECTIVE: The number of acute hospital beds is determined by health authorities using methods based on ratios and/or target bed occupancy rates. These methods fail to consider the variability in hospitalization demands over time. On the other hand, the implementation of sophisticated models requires the decision concerning the number of beds to be made by an expert. Our aim is to develop a new method that is as simple to use as the ratio method while minimizing the roundabout approaches of these methods. METHOD: A score was constructed with three parameters: number of transfers due to lack of space, number of days with no possibility for S unscheduled admissions and number of days with at least a threshold of U unoccupied beds. The optimal number of beds is the number for which both the mean and the standard deviation of the score reach their minimum. We applied this method to two internal medicine departments and one urological surgery department and we compared the solutions proposed by this method with those put forward by the ratio method. RESULTS: The solutions proposed by this method were intermediate to those calculated by the local and national length of Stays ratio methods. Simulating an unusual increase in admission requests had no consequence on the bed number selected, indicating that the method was robust. CONCLUSION: Our tool represents a real alternative to the ratio methods. A software has been developed and is now available for use.

Algorithms↗
PubMed2003

A universal method for determining intensive care unit bed requirements.

OBJECTIVE: Most methods used to estimate ICU bed needs rely either on simple formulas that do not consider the actual needs of the population or on simulations that are too specific to be applicable to all hospitals. We sought to develop a universally applicable nonparametric method. DESIGN AND SETTING: For each day, the number of immediate patient transfers to other ICUs because of a full unit and the number of patients treated in the ICU were collected. The number of beds needed was selected according to the minimization of both the mean and the variance of three parameters (accessibility, safety, and efficiency). This method was applied to the ICU of a general hospital. Robustness of the model was assessed using outliers. MAIN RESULTS: During the 5-month study period, 215 ICU stays were collected. The method selected a ten-bed model whereas length-of-stay ratio and case-mix methods selected a twelve- and height-bed models respectively. An unusual increase in admission requests had no consequence on the bed number selected, indicating that the method was robust. None of the parameters were dependent on specific ICU characteristics, establishing that this method is applicable to any type of hospital ward. CONCLUSION: Our model is reliable for determining the number of beds needed in any type of ICU and can be used by all ICU managers. The software is available.

Beds↗
PubMed1999

Temperature monitoring practices during regional anesthesia.

UNLABELLED: Monitoring and maintaining body temperature during the perioperative period has a significant impact on the risk of myocardial ischemia, cardiac morbidity, wound infection, surgical bleeding, and patient discomfort. To test the hypothesis that body temperature is inadequately monitored during regional anesthesia (RA), we randomly surveyed 60 practicing anesthesiologists to determine practice patterns for temperature monitoring. Only 33% of the clinicians surveyed routinely monitor body temperature during RA. Although skin temperature monitoring has limitations, it was the most commonly used method among the survey respondents. When temperature is monitored during RA, most clinicians use either liquid crystal skin-surface monitoring or axillary temperature probes. Of those surveyed, < 15% use acceptable core temperature monitoring techniques (urinary bladder or tympanic membrane). In conclusion, it seems that body temperature is often not monitored in patients receiving RA. IMPLICATIONS: The results of this survey of practicing anesthesiologists indicate that body temperature is often not monitored in patients receiving regional anesthesia. It is therefore likely that significant hypothermia goes undetected and untreated in these patients.

Anesthesia, Conduction↗
PubMed1998

[Morphometric study of the wall of the caudal vena cava after the implantation of a filter in the sheep].

The long stabilizers of the VT-LGM filter rest on large areas of the vascular wall. The morphometric study of the layers of the vascular wall, after implantation of filter in 15 ewes, divided into 3 groups of follow-up (2, 4 or 8 weeks) of 5 animals, was made at 3 levels opposite the filter and 1 level outside of it. Changes are seen for all the layers. Filter produces intimal hyperplasia. Stabilizers are quickly isolated from the blood flow. The thickness of the intimal hyperplasia grows for 4 weeks. It is more important at the base of the filter than at its head. There is also hyperplasia of the media with no change according to the follow-up or the level opposite the filter. The adventitia becomes thinner without variation of time or level of the filter. Smooth muscle cells of the adventitia become less frequent and smaller. Their density in front of the stabilizers, is the smallest by 4 week follow-up and remains the same along the stabilizer. The full thickness of the wall is bigger opposite the stabilizers than between them. The filter produces changes that are limited in time and in space. The most important changes are seen at 4 weeks after insertion and opposite the stabilizers.

Animals↗
PubMed1997

Decreased cytotoxic activity of natural killer cells in kidney allograft recipients treated with human HLA-derived peptide.

Peptides derived from a conserved region (aa 75-84) of HLA class I, overlapping the supertypic HLA-BW4/BW6 antigen region, have been shown to exhibit nonallele restricted immunosuppressive properties in rats and mice, prolonging survival of major histocompatibility complex-mismatched allografts. Furthermore, HLA-B7 peptides inhibit alloreactive cytotoxic cells, and both HLA-B7 and HLA-B2702 peptides inhibit natural killer (NK) cytotoxicity in vivo. In this article, we report on a randomized, controlled study of the safety and pharmacokinetics of HLA-B2702-derived peptide in human recipients of a first kidney allograft. Escalating doses of HLA-B2702 were compared with doses of placebo controls. No toxicity and no immunization against the peptide were noted. Although the study was not designed as an efficacy trial, patients who received the high-dose protocol (7 mg/kg) did experience more rejection episodes, but this was not statistically significant when compared with control patients. Interestingly, in human recipients, as previously observed in rodents, administration of the peptide was associated with a statistically significant decrease in the cytotoxicity of NK cells against K562 targets (P<0.001). As these peptides correspond to a region of the HLA class I molecule that interacts with the newly described NK receptors for class I, their mode of action through interaction with such receptors is discussed. As a peptide of the same sequence from HLA-B7 blocks both NK and alloreactive T cell cytotoxicity, it is possible that, in humans too, both types of cytotoxic cells are affected by this peptide. The biological significance of these observations should be confirmed in future controlled studies with a larger patient population.

Acute Disease↗
PubMed1996

Risk factors for chronic rejection in pediatric renal allograft recipients.

To determine the risk factors predictive of graft loss from chronic rejection in pediatric renal allograft recipients, we reviewed the collaborative study database of the Société de Néphrologie Pédiatrique which registered 314 grafts from January 1987 to December 1991. Of the 289 grafts analyzed, 71 failed during follow-up, chronic rejection being the most common cause of graft loss (35%). The clinical features of the chronic rejection group (n = 25) were compared with those of the group without failure (n = 218). The variables tested by monovariate analysis were cyclosporine dose at 1 year, donor type, donor and recipient age, and acute rejection episodes. The incidence of graft loss due to chronic rejection was 4% (4/109) in patients who had no acute rejection and 16% (21/134) in those with at least one acute rejection episode (P = 0.002). Donor age (< or = 5 years) was a risk factor for chronic rejection (P = 0.024). Recipient age and donor type were not significantly different between the chronic rejection group and the control group. Using time-dependent covariates, the risk factors were an acute rejection episode (P = 0.003) and low cyclosporine doses at 1 year (P = 0.02). We conclude that acute rejection and low cyclosporine doses in these pediatric patients were risk factors for graft loss due to chronic rejection.

Adolescent↗
PubMed1996

Effects of a 33 residue interleukin-1 beta peptide and the antioxidant PQQ on interleukin-1 beta-mediated inhibition of glucose-stimulated insulin release from cultured mouse pancreatic islets.

Interleukin-1 beta (IL-1 beta) significantly inhibits insulin secretion from glucose stimulated islet cells. The mechanism for this inhibition has been hypothesized to be due to stimulation of the inducible form of nitric oxide synthase and a resulting increase in nitric oxide (NO) concentration. Ways to block the effect of IL-1 beta have focused on blocking the binding of IL-1 beta to the IL-1 receptor and the use of antioxidants to neutralize increases in NO. This report focuses on a 33 residue peptide synthesized based on the C-terminal region of the IL-1 beta molecule, a reported binding site of the IL-1 beta molecule, and the redoxcycling antioxidant pyrroloquinoline quinone (PQQ). The 33 residue peptide did not function as an antagonist, but as a weak agonist. High concentrations of PQQ itself inhibited glucose-dependent insulin release while low concentrations did not. PQQ had no effect on the actions of IL-1 beta. Three isosteric and isomeric analogues of PQQ were also investigated. One of the PQQ isomers had an inhibitory effect on insulin secretion at low concentrations where PQQ had no effect. These results reflect the sensitivity of islets to oxidative stress.

Amino Acid Sequence↗
PubMed1996

[Value of plain abdominal radiography for evaluating the patency of LGM caval filters].

OBJECTIVES: To evaluate the value of plain abdominal X-Ray to detect vena Tech LGM filter occlusion or patency during follow-up. METHODS: Eighty-nine patients were followed in a prospective study for 2 to 6 years after vena Tech LGM filter implantation. The control examination consisted in a clinical examination, a plain abdominal X-Ray (to measure expansion index = diameter/height of the filter and to detect migration and angulation) and a Doppler ultrasonography and/or a cavography to appreciate filter patency. RESULTS: 175 plain abdominal X-Ray, 172 Doppler ultrasonographies and 28 cavographies were done. Sensitivity and specificity of retraction to suspect a filter obstruction were respectively: 82.3% and 86.1%; if expansion index was lower or equal to 0.34 its sensitivity and specificity were 100% and 92.1%. The negative predictive values of retraction and of the association retraction-migration to exclude a filter obstruction were 85.1% and 96%. CONCLUSION: Absence of migration or retraction on plain abdominal X-Ray during the follow-up is highly predictive of filter patency. This limits the use of Doppler ultrasonography and cavography.

Adult↗
PubMed1996

Single-center analysis of 468 first cadaveric kidney allografts with a uniform ATG-CsA sequential therapy.

Progress in clinical management and sophistication of immunological treatment of kidney allografts depend upon continuous reassessment of the risk factors related to pre- and post-graft information according to the therapeutical strategies used. We studied predictive factors of long-term graft survival (up to 9 years) and of kidney graft function at one year after surgery in a single-center population of 468 first cadaveric kidney recipients treated with a uniform immunosuppression induction regimen of anti-thymocyte globulin, followed by cyclosporine A. The statistical analysis showed that long-term graft survival was highly correlated with the occurrence of one or more acute cellular rejections and with the timing of these episodes. In addition, this uniformly treated series of patients confirmed the potential importance of gender matching. The magnitude of anti-HLA immunization and delayed graft function were also strongly linked to low graft survival rates. We found no significant influence of HLA matching, with serological HLA typing, on graft loss. The quality of graft function at one year was found to be a strong prognostic factor of long-term graft survival. In addition, the impact of pre- and post-graft parameters were studied in terms of prediction of one-year graft function. A stepwise multivariate analysis showed that graft function at one year was a multivariate phenomenon strongly correlated with a history of acute rejection episodes and with donor and recipient age. However, these 3 factors could account for only 15% of the graft function deterioration, the remaining 85% might be explained in part by chronic cyclosporine toxicity and/or chronic rejection.

Adolescent↗
PubMed1995

Increased plasma levels of human interleukin for DA1.a cells/leukemia inhibitory factor in sepsis correlate with shock and poor prognosis.

Animal study results have suggested a role in sepsis for human interleukin for DA1.a cells/leukemia inhibitory factor (HILDA/LIF). HILDA/LIF and interleukin-6 (IL-6) levels were prospectively studied by serial ELISAs in 34 septic patients. HILDA/LIF was detected in 11 of 34 patients at plasma levels of 100-37,000 pg/mL. Peak HILDA/LIF levels correlated with increased temperature and creatinine and IL-6 and with decreased arterial CO2 (P < .05). Multivariate analysis showed that shock and decreased arterial CO2 accounted for 75% of peak HILDA/LIF plasma variations (R2 = .753). Fatal outcome was most often associated with detectable HILDA/LIF (> 56 pg/mL) and peak IL-6 plasma levels > 850 pg/mL (sensitivity, 83%; specificity, 87%), but both (at respective levels of > 480 and > 850 pg/mL) were associated with fatal outcome. HILDA/LIF was detected in septic patients exhibiting shock, and its levels correlated with higher mortality and shorter survival.

APACHE↗
PubMed1995

[Two-stage excision of extensive cutaneous carcinoma of the face. A retrospective study of 80 patients].

INTRODUCTION: Delayed reconstruction (two-step surgery) comprised of tumor resection and repair three or four days later, after paraffin tissue fixation and histopathological examination, is one of the techniques used for complete excision of spreading cutaneous carcinomas. PATIENTS AND METHODS: In order to evaluate the efficacy and long term prognosis of delayed reconstruction surgery, we carried out a retrospective study of 80 patients treated by this method and (Kaplan- Meier) for correlation with the local recurrence rate: sex, age, anatomic site, histologic type and existence of previous therapy. Long term results have been estimated. Among the 80 patients studied, 76 patients have been followed. The sex-ratio was 0.48. Fifty-two percent of the population was more than seventy years old. Fifty-five percent of the tumors were situated on the nose. In 32,5 p. 100 of the cases, a prior therapy (surgery, electrodessication or radiation therapy) has been carried out. Histological analysis showed 87 p. 100 basal cell carcinomas (of which 26 p. 100 of morpheaform basal cell carcinomas) and 13 p. 100 squamous cell carcinomas. RESULTS: After the first operative step, there was total excision in 69 p. 100 of thecases. In the remaining cases, a second excision was performed with a margin of normal tissue. Recurrences were observed (some precocious recurrences and some late recurrences) in 18.4 p. 100 of the cases. No risk factor correlated significantly with the recurrence rate. However, analysis of the survival graph suggests that the squamous cell carcinomas recurred more often than the basal cell carcinomas. CONCLUSIONS: Although extemporaneous examinations (Mohs' technique) remains the gold standard technique in the management of spreading cutaneous carcinomas of the face, the delayed reconstruction (two-step surgery) is a credible alternative when compared to the recurrence rates reported in the literature with the other techniques (electrodessication, radiation therapy or cryosurgery).

Actuarial Analysis↗
PubMed1994

Epidemiologic approach to human toxocariasis in western France.

Toxocara canis is a common parasite in puppies. The danger to human health has not been properly established. We estimated the current incidence of this pathogen in two western districts of France, Loire-Atlantique and Maine et Loire. Blood samples from 1836 eosino-philic patients were collected and tested by an enzyme-linked immunosorbent assay (ELISA) excretory-secretory Toxocara antigen test. We obtained positive results in 22% of the cases and highly positive results in 7%. The ELISA data seemed to be age-dependent, with older patients having more positive results (P < 0.0001). The interlaboratory distribution of positive test results was statistically significantly different (P < 0.0001), suggesting regional sources. The main clinical expressions of toxocariasis were: asthenia, gastric pain, and pulmonary disease. Individual and collective surveys of this zoonotic disease need to be carried out.

Animals↗
PubMed1993

Vena Tech-LGM filter: long-term results of a prospective study.

Efficiency and tolerance of the Vena Tech-LGM filter were assessed in 142 patients prospectively studied during a 2-6-year follow-up period. No patients were lost to follow-up, and 137 (91.3%) scheduled control examinations were performed. Fifty-three patients died of causes unrelated to thromboembolic disease. Pulmonary embolism was suspected in five surviving patients (3.5%). Sixteen retractions (18.4%), 16 intracaval migrations (18.4%), and one tilt were observed. Filter patency studied at Doppler ultrasonography, with or without phlebocavography, gave the following results according to the Kaplan-Meier actuarial method: 92% patency after 2 years of follow-up, 80% after 4 years, and 70% after 6 years. Vena Tech-LGM filter obstruction was related to retraction (P < 10(-6)) or distal migration (P < .004). Occurrence of trophic disease in the lower limbs during the follow-up period was related to the initial level of deep venous thrombosis (P = .03) and had no relation to the patency of the filter. The filter was effective in preventing pulmonary embolism, with 70% demonstrating long-term patency, and no deleterious effects were imputed to obstructions observed during follow-up.

Actuarial Analysis↗
PubMed1991

[Anxiolytic agents and hypnotic drugs in Bretagne. Pharmaco-epidemiological study].

A pharmacoepidemiological survey was carried out in a rural region of France (Brittany) with the help of 54 general practitioners, all of whom belong to a clinical research group. The aim of the survey was 3-fold: to determine the frequency (incidence and prevalence) of anxiolytic and hypnotic drug prescriptions, the sociological characteristics of these drug consumers, and the indications and reasons for prescribing this class of drugs. The population of hypnotic drug and sedative consumers was strikingly dominated by women, 60 years old and over, retired or without a profession. Prescription analysis revealed that these drugs were essentially benzodiazepines whose prevalence and incidence were 17 and 1.76%, respectively. A high frequency of prescription renewals (78%) and an elevated percentage of long-term treatments (more than 9 years) were also noted. Insomnia and dependence are the two main "risk factors" for drug treatments lasting more than one year.

Adult↗