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Biomedical subjects

A Lavoie

Publications and source records attributed to A Lavoie.

At least 37 records · Page 2Linked to original sources
PubMed1995

Trauma center designation: initial impact on trauma-related mortality.

The movement towards trauma care regionalization in Québec was initiated in 1990, with formal designation of three level I trauma centers in 1993. The purpose of this study is to evaluate the impact of trauma center designation on mortality. The study design is that of a two-cohort study, one assembled during 1987 when designation was not in effect, and the other during the first 5 months of designation. The study focuses on patients that fulfilled the following criteria: i) arrived alive at the hospital, and ii) were admitted. The outcome measures are adjusted mortality, and excess mortality as measured by the TRISS methodology. A total of 158 patients treated in 1987, and 288 treated in 1993, were identified. The mean age of the patients treated in 1993 was significantly higher (40.0, +/- 18.1), when compared with the 1987 group (30.9 +/- 18.1; p < 0.001). Patients in the 1987 cohort had a significantly higher proportion of injuries caused by stabbing (p = 0.02), and a significantly lower proportion caused by falls (p = 0.003). The 1987 cohort had a higher rate of abdominal injuries (p = 0.0001), and external injuries (p = 0.0001), and a significantly lower rate of head or neck injuries (p = 0.003), and injuries to the extremities (p = 0.0001). The mean Injury Severity Score (ISS) for the 1987 cohort was 14.96 (+/- 12.36), and 15.49 (+/- 11.61) in 1993 (p = 0.65). The crude mortality rate was 20% for 1987, and 10% for 1993. The crude odds ratio for mortality in 1987 was 2.10 with 95% confidence intervals between 1.22 and 3.62 (p = 0.006).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Preventable death evaluation of the appropriateness of the on-site trauma care provided by Urgences-Santé physicians.

The study is based on 44 preventable deaths occurring in a cohort of 360 patients with major trauma. These cases were reviewed by a committee of nine experts. The mean Injury Severity Score (ISS) was 28, and most cases had injuries to the head/neck (68%) and chest (64%). The mean (+/- SD) observed prehospital times, and those considered the maximum allowable by the committee, were 40.6 +/- 12.0 minutes for head/neck injuries and 23.9 +/- 12.2 minutes for chest injuries (p < 0.05). Intravenous (i.v.) lines were started in 38 (86%) of the patients. The committee classified this procedure as harmful for 16 (42%) and neutral for 19 (50%). Among the 18 (46%) that were intubated, this intervention was considered harmful for 17% and neutral for 39%. In two of the three patients for whom a pneumatic antishock garment was applied, this procedure was considered harmful. Of the 34 patients that required direct transport at a level I trauma center, 50% were transferred to such a hospital. These results show significant prehospital delays and high rates of inappropriate IV line initiation and intubation in trauma patients receiving on-site care by physicians. We conclude that prehospital care protocols for trauma patients should emphasize prompt transport and specific on-site care algorithms.

Adult↗
PubMed1995

A simple method to detect expiratory flow limitation during spontaneous breathing.

Patients with severe chronic obstructive pulmonary disease (COPD) often exhale along the same flow-volume curve during quiet breathing as during a forced expiratory vital capacity manoeuvre, and this has been taken as indicating flow limitation at rest. To obtain such curves, a body plethysmograph and the patient's co-operation are required. We propose a simple technique which does not entail these requirements. It consists in applying negative pressure at the mouth during a tidal expiration (NEP). Patients in whom NEP elicits an increase in flow throughout the expiration are not flow-limited. In contrast, patients in whom application of NEP does not elicit an increase in flow during most or part of the tidal expiration are considered as flow-limited. Using this technique, 26 stable COPD patients were studied sitting and supine. Eleven patients were flow-limited both seated and supine, eight were flow-limited only when supine, and seven were not flow-limited either seated or supine. Only 5 of 19 patients who were flow-limited seated and/or supine had severe ventilatory impairment (forced expiratory volume in one second (FEV1) < 40% predicted). We conclude that the NEP technique provides a simple, rapid, and reliable method for detection of expiratory flow limitation in spontaneously breathing subjects, which does not require the patient's co-operation, and can be applied in different body positions both at rest and during muscular exercise. Our results also indicate a high prevalence of flow limitation in COPD patients at rest, particularly when supine.

Aged↗
PubMed1994

Detection of expiratory flow limitation during mechanical ventilation.

Two new methods, application of negative pressure at the airway opening during expiration (NEP) and reduction of flow resistance by bypassing the expiratory line of the ventilator by exhaling into the atmosphere (ATM), were used to detect expiratory flow limitation in 12 semirecumbent (45 degree) mechanically ventilated patients, seven with chronic airway obstruction (CAO). An increase of expiratory flow with NEP or ATM, relative to the preceding control breath, was taken as indicating absence of expiratory flow limitation. By contrast, the portion of the tidal expiration over which there was no change in flow with NEP or ATM was considered as flow-limited. With NEP, nine patients exhibited flow limitation, six (all with CAO) were flow-limited over most of the tidal expiration (> 70% VT), and three at < 60% VT. Although the results with NEP and ATM were in general in good agreement, in the three non-flow-limited patients the ATM method gave erroneous results. Six patients were also studied supine, including two who were not flow-limited when semirecumbent: both became flow-limited when supine. We conclude that NEP provides a simple method to detect flow limitation in mechanically ventilated patients. The supine position enhances flow limitation.

Aged↗
PubMed1993

Chronic idiopathic urticaria: possible contribution of histamine-releasing factor to pathogenesis.

BACKGROUND: Histamine-releasing factor was recently shown to be clinically relevant in allergic rhinitis and asthma. HRF could also be involved in the pathogenicity of chronic idiopathic urticaria (CU). The purpose of this study was to investigate the role of HRF in the pathophysiology of CU. METHODS: Blisters were induced on lesional and nonlesional skin of 12 patients with CU and on normal skin of five control subjects. HRF activity and histamine content were measured in all samples recovered from each skin site. RESULTS: Significantly more HRF was found in blister fluids from lesional skin of patients with CU as compared with nonlesional skin and skin of control subjects. In addition, histamine content in blister fluids from affected skin of patients with CU was significantly higher in comparison with both nonlesional skin of patients with CU and skin of control subjects. HRF activity was also higher in blister fluids from nonlesional skin of patients with CU than that of control subjects, in spite of equivalent histamine content. CONCLUSION: These data suggest that the inflammatory reaction found in CU disease is associated with the cutaneous release of HRF.

Adult↗
PubMed1993

In utero acute graft-versus-host disease in a neonate with severe combined immunodeficiency.

We describe a male neonate with severe combined immunodeficiency who at birth had acute graft-versus-host disease (GVHD) as a result of maternal-fetal transfusion during pregnancy. Several clinical signs helped establish this diagnosis. Findings of a skin biopsy specimen confirmed the diagnosis of acute GVHD. Immunologic evaluation disclosed an absence of T and B lymphocytes. Acute GVHD in severe combined immunodeficiency most often occurs during the first weeks of life; intrauterine occurrence is unusual.

Biopsy↗
PubMed1993

Impact of on-site care, prehospital time, and level of in-hospital care on survival in severely injured patients.

A sample of 360 severely injured patients was selected from a cohort of 8007 trauma victims followed prospectively from the time of injury to death or discharge. A case referent study was used to test the association between on-site care, total prehospital time, and level of care at the receiving hospital with short-term survival. Multiple logistic regression analyses showed that use of Advanced Life Support (ALS) at the scene was not associated with survival, whereas treatment at a level I compatible hospital was associated with a 38% reduction in the odds of dying, which approached statistical significance. Total prehospital time over 60 minutes was associated with a statistically significant adjusted relative odds of dying (OR = 3.0). The results of this study support the need for regionalization of trauma care and fail to show a benefit associated with ALS.

Adult↗
PubMed1992

Chronic idiopathic urticaria: profiles of skin mast cell histamine release during active disease and remission.

Chronic idiopathic urticaria (CIU) is characterized by the increased releasability of histamine by mast cells in normal-appearing skin. In active CIU, this abnormality is consistently present. To determine if this finding subsides when the disease goes into remission phase, we analyzed the histamine secretion in patients with CIU in remission (CIUR) compared with that of patients with CIU and in normal control (NC) subjects, with the skin-chamber technique. The profiles of histamine release in sites challenged with compound 48/80 were significantly different in the groups with CIU and CIUR. Furthermore, patients with CIUR did not differ from NC subjects in terms of histamine releasability under compound 48/80 stimulation (p greater than 0.1). These data suggest that the state of excessive skin mast cell sensitivity is a reversible and transient phenomenon in CIU disease.

Analysis of Variance↗
PubMed1992

Allergic rhinitis to ragweed pollen. I. Reassessment of the effects of immunotherapy on cellular and humoral responses.

This work presents a double-blind, placebo-controlled study of 27 patients with allergic rhinitis to ragweed who received preseasonal desensitization immunotherapy [IT] with alum-precipitated aqueous ragweed extracts. We reassessed the following parameters in relation to clinical responses: clinical scores, nasal reactivity to a provocative dose of ragweed causing a 75% fall in airflow rate (PD75), ragweed IgE and IgG, and ragweed-induced basophil histamine release (BHR). First, the nasal PD75 correlated with the severity of nasal symptoms (p less than 0.05). Second, we confirmed a significant symptomatic improvement in the IT-treated group either by clinical scores (p less than 0.05) or the prevention of the seasonal fall of the PD75 (p less than 0.005). Also, IT reduced the seasonal rise of IgE (p less than 0.02) and induced an increase in IgG (p less than 0.01) and a decrease in BHR (p less than 0.03). There was a significant correlation between IgE and BHR (r = 0.80; p less than 0.01). After selecting out the effects of IgE, the BHR was still higher in the placebo-treated group than in the IT-treated group (p less than 0.02), suggesting the involvement of other modulating factors. Symptomatic improvement after IT correlated only with the summation of both IgE and BHR (PD75; r = 0.64; p less than 0.005). This observation suggests that the severity of clinical symptoms is determined by several interacting factors and not by the antibody response alone.

Adult↗
PubMed1992

Allergic rhinitis to ragweed pollen. II. Modulation of histamine-releasing factor production by specific immunotherapy.

A number of cytokines, including histamine-releasing factors (HRFs), have a role to play in IgE-mediated asthma. However, the influence of HRF in allergic rhinitis without asthma remains to be revealed. This article presents a double-blind, placebo-controlled study on the role of HRF in ragweed-allergic rhinitis and its modulation by natural pollen exposure and specific immunotherapy (IT). Twenty-seven patients allergic to ragweed were randomly assigned to receive either preseasonal alum-precipitated aqueous extracts of ragweed or placebo. Before the onset of therapy and during the ragweed-pollen season, subjects were evaluated for each of the following: clinical scores, ragweed IgE and IgG antibody levels, and spontaneous and allergen-driven HRF production. Thirteen nonatopic volunteers were also studied in the same protocol. First, before the initiation of therapy, more HRF was produced by both unstimulated and ragweed-stimulated mononuclear cells (MNCs) of atopic subjects as compared to MNCs of nonatopic subjects. Second, MNCs of the placebo-treated group produced significantly more spontaneous and ragweed-specific HRF during the pollen season compared to the preseasonal values. Finally, specific IT not only improved the clinical manifestation of allergy but also prevented the seasonal rise of spontaneous and ragweed-driven HRF production, along with a well-known change in other immunologic parameters associated with successful IT.

Adult↗
PubMed1992

Standardized mortality ratio analysis on a sample of severely injured patients from a large Canadian city without regionalized trauma care.

Flora's Z statistic and standardized mortality ratios (SMRs) as indicators of excess mortality were calculated for a sample of 355 patients with major trauma. A statistically significant overall excess mortality was observed in this sample (Z = 6.77, SMR = 1.81, p less than 0.05). Advanced life support provided by physicians at the scene (MD-ALS) was not associated with reduced excess mortality. A significant trend toward lower excess mortality was associated with a higher level of trauma care at the receiving hospital (p less than 0.05). Total prehospital time over 60 minutes was associated with a significant increase in excess mortality (p less than 0.001). These results support regionalization of trauma care and failed to show any benefit associated with MD-ALS.

Adolescent↗
PubMed1989

Anti-Staphylococcus aureus IgE antibodies for diagnosis of hyperimmunoglobulinemia E-recurrent infection syndrome in infancy.

Four infants with hyperimmunoglobulinemia E presented with a persistent papulovesicular rash and eosinophilia. Serum IgE levels and specific anti-Staphylococcus aureus IgE antibodies were studied during the first year of life. Increased anti-S aureus IgE antibodies were an early indicator of the disease; they appeared as soon as 7 weeks of age in patient 1 and before 1 year of age for the other patients. These antibodies were detected before the development of deeper staphylococcal infections. Prompt diagnosis and treatment are important, as they may prevent long-term infectious complications.

Antibodies, Viral↗
PubMed1988

Nonrandom X chromosome inactivation in B cells from carriers of X chromosome-linked severe combined immunodeficiency.

X chromosome-linked severe combined immunodeficiency (XSCID) is characterized by markedly reduced numbers of T cells, the absence of proliferative responses to mitogens, and hypogammaglobulinemia but normal or elevated numbers of B cells. To determine if the failure of the B cells to produce immunoglobulin might be due to expression of the XSCID gene defect in B-lineage cells as well as T cells, we analyzed patterns of X chromosome inactivation in B cells from nine obligate carriers of this disorder. A series of somatic cell hybrids that selectively retained the active X chromosome was produced from Epstein-Barr virus-stimulated B cells from each woman. To distinguish between the two X chromosomes, the hybrids from each woman were analyzed using an X-linked restriction fragment length polymorphism for which the woman in question was heterozygous. In all obligate carriers of XSCID, the B-cell hybrids demonstrated preferential use of a single X chromosome, the nonmutant X, as the active X. To determine if the small number of B-cell hybrids that contained the mutant X were derived from an immature subset of B cells, lymphocytes from three carriers were separated into surface IgM positive and surface IgM negative B cells prior to exposure to Epstein-Barr virus and production of B-cell hybrids. The results demonstrated normal random X chromosome inactivation in B-cell hybrids derived from the less mature surface IgM positive B cells. In contrast, the pattern of X chromosome inactivation in the surface IgM negative B cells, which had undergone further replication and differentiation, was significantly nonrandom in all three experiments [logarithm of odds (lod) score greater than 3.0]. These results suggest that the XSCID gene product has a direct effect on B cells as well as T cells and is required during B-cell maturation.

Alleles↗
PubMed1986

Brain maturity in regard to the auditory brainstem response in small-for-date neonates.

The auditory brainstem response has been used in neonates at risk of hearing impairment or as a functional measurement of brain maturity. The goal of the present study was to evaluate the auditory brainstem response in small-for-date newborns, in relation to changes observed with fetal maturity in a control group. Compared to controls with similar maturity, a significant delay for the appearance of waves III and V, and between waves I-V was observed in the small-for-date newborns, suggesting an alteration of the auditory pathway within the brainstem rather than an impairment of the peripheral auditive apparatus. Indeed, small-for-date newborns reacted to the test in a similar manner as premature babies in whom such a delay was also observed. Our data would suggest a functional brain immaturity in small-for-date newborns, during the first days of life, in regard to the auditive evoked potential, which may be related to some alterations in brain development reported with fetal malnutrition.

Birth Weight↗
PubMed1986

[Chemotherapy in 143 advanced epithelial cancers of the ovary. Experience at the Hôtel-Dieu of Quebec and Hôpital Saint-Antoine (Paris)].

Results of initial chemotherapy in 143 patients with advanced epithelial ovarian cancer are presented. Twenty-five patients were treated with alkylating agents, their median survival was 13 months and 15% were alive at 4 years. Nineteen received Cyclophosphamide-Methotrexate-5 Fluorouracil with or without Hexamethylmelamine, median survival was 22 months and 4 years survival was 20%. Forty-eight were treated with Adriamycin and Cisplatinum, their objective response rate proven by second-look laparotomy was 54.4% (26.1% complete response), median survival was 23 months and 35% were alive at 4 years. Thirty-one received Hexamethylmelamine, 5 Fluorouracil, Adriamycin and Cisplatinum with a median survival of 18 months and 4 years survival of 15%. Twenty had various other chemotherapy regimens, their median survival was only 8 months. Recent advances in the therapy of ovarian carcinoma are also discussed.

Altretamine↗
PubMed1985

Adriamycin and cis-platinum in advanced ovarian cancer.

Forty-eight patients with stage III and IV ovarian epithelial carcinoma were treated with single doses of adriamycin (ADM) 50 mg/m2 and cis-platinum (DDP) 50 mg/m2 every month for nine courses. The pathologically proven response rate was 52.2%, with 22.7% complete response and 29.5% partial response. Median survival was 22 months for all patients, 25 months in stage III and 15 months in stage IV. This study confirms that ADM-DDP is a valuable drug regimen in advanced ovarian carcinoma but further progress is needed to improve the cure rate, which remains low.

Antineoplastic Combined Chemotherapy Protocols↗