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J Laurent

Publications and source records attributed to J Laurent.

At least 19 recordsLinked to original sources
PubMed1999

Mechanisms of drug-induced allergic contact dermatitis.

Allergic contact dermatitis is induced by a wide variety of drugs that trigger specific immune responses following topical exposure. Identified chemical structures involved in such reactions include the mercuric and thiosalicylic acid groups of thimerosal, the diphenylketone group of the anti-inflammatory drug ketoprofen, the amide or ester structure of local anesthetics, and the side-chain and thiazolidine ring of beta-lactams. The T cell responses to such compounds involve CD4+ and CD8+ alphabeta+ T lymphocytes and also CD4 /CD8 gammadelta+ T cells. Although "T helper 2" cytokine production by drug-specific human T cells from patients with allergic contact dermatitis has been described, T helper 1-like and T cytotoxic 1-like responses clearly play key roles in this cutaneous reaction.

Allergens↗
PubMed1998

How good are deep phylogenetic trees?

Great interest is given to species emerging early in phylogenetic reconstruction because they are often assumed to represent an ancestor. Recent studies indicate, however, that species branching deep in molecular trees are often fast-evolving ones, misplaced because of the long-branch artefact. The detection of genuinely deep-branching organisms remains an elusive task.

Animals↗
PubMed1997

Size of cells collected from normal human subjects using contact lens cytology.

This paper describes how a soft contact lens can be used to harvest cells from the surface of the corneal epithelium. The procedure is called contact lens cytology (CLC). Cells were removed from a soft contact lens by irrigation and stained with acridine orange. Two methods for the measurement of cell size are described. First, cell size was measured using a computer-assisted technique, which calculated the area of the cell from its outline. The second method was simpler in that it required only a single measurement of the longest dimension of the cell (the cell length). To test the validity of this simpler method, cell area was compared with cell length in 185 cells. The resulting correlation (r = 0.92) suggests that the size of shed cells can be described adequately using cell length in place of the more time-consuming measurement of cell area. A mathematical relation can be used to convert cell length to cell area so that results from experimenters using different measures of size can be compared. When a large pool of cells collected by CLC was divided into four aliquots and cell length measured by two observers on two different days, there were no significant differences between observers or days. Thus, the technique does not depend on one observer, and it is unaffected by a 24-h delay in measurement. Cells were harvested from the corneal epithelium of normal human subjects. The number of cells collected from any single removal of the contact lens had a range of 10 to 175 cells, and a mean of 66.8 +/- 40.4 (N = 46). Cell length was measured and plotted as frequency histograms for both eyes of each subject. The range in cell length was from 10 to 80 microns. The mean cell length for individual subjects had a low of 26.5 +/- 9.0 microns and a high of 44.2 +/- 10.2 microns, with a grand mean for all right eyes of 36.0 +/- 5.1 microns, and a grand mean for all left eyes of 34.6 +/- 5.2 microns. The mean for all eyes was 35.3 +/- 5.1 microns. Composite histograms were created with the combined data from the 23 right eyes (N = 1310 cells), and the 23 left eyes (N = 1765 cells). Individual histograms and the composite histograms were not normally distributed. Peaks in the distributions suggest the presence of different subpopulations of cells, lending support to the hypothesis that there is more than one mechanism for cell shedding.

Adult↗
PubMed1997

Safety of Hymenoptera venom rush immunotherapy.

We studied 97 consecutive patients who had received Hymenoptera venom rush immunotherapy in our department. There were 53 males and 44 females, whose mean age was 46 years (8-74 years). Most study patients had experienced severe anaphylaxis induced by a Hymenoptera sting: the reaction was Müller stage IV in 48 patients. Skin tests were positive for Vespula venom in 85 cases, Polistes venom in 23, and bee venom in 23. Radioallergosorbent test values exceeded 0.70 kIU/l in 60 cases. Immunotherapy was performed with Vespula venom alone in 73 cases, bee venom alone in five cases, and both Vespula and bee venom in 19 cases. A cutaneous reaction was seen at the injection site in most patients. Four patients also had skin manifestations in areas remote from the injection site. Blood pressure elevation was seen in 11 patients, moderate hypotension in two, rhinitis in one, asthenia or headache in seven, visual disorders and vertigo in two, and transient dyspnea in two. Our protocol has proved very safe, epinephrine never being required in the 97 reported cases.

Adolescent↗
PubMed1997

Stress, alcohol-related expectancies and coping preferences: a replication with adolescents of the Cooper et al. (1992) model.

OBJECTIVE: The present study attempted to replicate with adolescents the stressor vulnerability model of adult drinking proposed by Cooper et al. (J. Abnorm. Psychol. 101: 139-152, 1992). The Cooper et al. model simultaneously assesses the stress-moderating effects of gender, expectancies and coping on alcohol use and abuse. METHOD: Adolescents in Grades 7-12 (N = 184, 59% female) completed the Alcohol Expectancy Questionnaire-Adolescent form, the COPE, the Adolescent Perceived Events Scale and the Drinking to Cope scale. RESULTS: The pattern of results was very similar to those of earlier studies using adults or undergraduates. Generally, positive expectancies for alcohol, an avoidant coping preference and stress were predictive of drinking to cope, alcohol use and alcohol-related problems. A number of two-way interactions were also reported. Although gender did not play a prominent role in prediction, as it typically does with adults, grade was a significant predictor; older students reported more alcohol use and alcohol-related problems than younger students. CONCLUSIONS: Results were similar to those reported by Cooper et al. with adults and Evans and Dunn (J. Stud. Alcohol 56: 186-193, 1995) with undergraduates, and support the utility of the stressor vulnerability model for understanding alcohol use among adolescents.

Adaptation, Psychological↗
PubMed1996

Desferrioxamine-dependent iron transport in Erwinia amylovora CFBP1430: cloning of the gene encoding the ferrioxamine receptor FoxR.

Iron deprivation of Erwinia amylovora CFBP1430, a species causing fire blight on Pomoïdeae, was shown to induce the production of siderophores of the desferrioxamine (dfo) family and two outer membrane polypeptides with apparent molecular weight of about 70 and 80 kDa, respectively. Cyclic dfo E was characterized as the major metabolite. Phage MudIIpR13 insertional mutagenesis and screening on CAS-agar medium yielded three dfo non-producing and one overproducing clones. These clones failed to grow in the presence of the Fe(III) chelator EDDHA and were determined further as dfo and ferrioxamine transport negative mutants, respectively. The transport mutant which appeared to lack the 70 kDa polypeptide in the outer membrane allowed the purification of dfo E. Growth under iron limitation of dfo negative mutants was stimulated with ferrioxamine E and B but not with other ferrisiderophores tested. The host DNA sequence flanking the left terminal part of the MudIIpR13 prophage responsible for the transport mutation was cloned and used to probe a parental gene library by DNA-DNA hybridization. Two recombinant cosmids restoring the transport mutation to normal were identified. Both cosmids also conferred the ability to utilize ferrioxamine B and E as iron sources on a FhuE- mutant of Escherichia coli. This correlated with the production of an additional polypeptide of 70 kDa in the outer membrane of E. coli transconjugants, thus confirming that this protein serves the ferrioxamine receptor function (FoxR) in E. amylovora.

Bacterial Outer Membrane Proteins↗
PubMed1996

Exercise-induced anaphylaxis: useful screening of food sensitization.

BACKGROUND AND OBJECTIVES: Exercise-induced anaphylaxis is a well-defined entity as described by Sheffer and Austen. Exercise-induced anaphylaxis can be associated with ingestion of a specific food. We report our experience with a series of cases of exercise-induced anaphylaxis in which anaphylaxis was considered to be associated with food allergy. METHODS: We observed 19 patients in whom severe systemic signs of anaphylaxis occurred during or immediately after exercise, while the severity of reactions excluded challenge testing. The causal relationship with various foods was systematically investigated in all cases, even in the absence of any history of allergy. RESULTS: Sensitization to wheat flour was demonstrated in 12 patients, to peanut in seven, and to tree nuts in six cases with skin tests and/or RAST. Sensitivity to various other foods was found less often. Further, avoidance of specific foods according to results of skin tests and RAST was systematically observed during the five hours prior to exercise and no symptom occurred, suggesting a role of specific food intake in the pathogenesis of exercise-induced anaphylaxis. With such elimination diets, most of these young patients were able to engage in regular vigorous exercises (more than twice a week in some cases) without any clinical manifestation with a median followup of 2 years. In two patients, however, recurrence of exercise-induced anaphylaxis was subsequently explained by concomitant ingestion of other foods such as rice and peanut. Additional avoidance of these foods before exercise was then effective in 14 cases (median follow up: 2 years). CONCLUSIONS: Investigations to detect food sensitization, in particular to wheat, peanut and/or tree nuts, and specific avoidance of these foods five hours before exercise appear essential in cases of exercise-induced anaphylaxis.

Adolescent↗
PubMed1996

Tripartite structure of positive and negative affect, depression, and anxiety in child and adolescent psychiatric inpatients.

The tripartite model of depression and anxiety suggests that depression and anxiety have shared (generalized negative affect) and specific (anhedonia and physiological hyperarousal) components. In one of the 1st studies to examine the structure of mood-related symptoms in youngsters, this model was tested among 116 child and adolescent psychiatric inpatients, ages 8-16 (M = 12.46; SD = 2.33). Consistent with the tripartite model, a 3-factor (Depression, Anxiety, and Negative Affect) model represented the observed data well. Follow-up analyses suggested that a nonhierarchical arrangement of the 3 factors may be preferable to a hierarchical one.

Adolescent↗
PubMed1996

Mixed neuronal-glial tumors (gangliogliomas) in children.

Mixed tumors account for about 10% of the childhood central nervous system tumors. Studies of the most common tumor, the ganglioglioma, in patients of all ages suggest that optimal therapy is total gross resection. There are few studies on these tumors in children. In our institution between 1984 and 1993, 28 children with gangliogliomas (4 of which were anaplastic) and 4 children with dysembryoplastic neuroepithelial tumors were treated and followed. Fourteen had local subarachnoid involvement. Total gross resection was usually curative, regardless of histology. Subarachnoid involvement was not indicative of a poorer prognosis.

Adolescent↗
PubMed1996

[Desensitization].

Explore the source record for details and available documents.

Desensitization, Immunologic↗
PubMed1995

Liver transplantation in two cases of propionic acidaemia.

Orthotopic liver transplantation (OLT) was performed in two patients with propionic acidaemia, a 7-year-old boy and a 9-year-old girl, diagnosed with a severe neonatal form with high risk of metabolic decompensation. In both cases the metabolic liver functions recovered within the 12 postoperative hours; no clinical symptoms of propionic acid toxicity, metabolic acidosis, severe hyperammonaemia, hyperglycinaemia or haematological abnormalities were observed. In both cases insulin-dependent diabetes mellitus occurred early after OLT (persisting in the boy's case). Severe post-transplantation complications were observed (acute rejection and CMV infection in both patients) which did not trigger metabolic decompensation. The boy developed chronic rejection and vanishing bile duct syndrome due to incomplete hepatic arterial thrombosis. He required permanent in-patient care with chronic hyperammonaemia and neurological sequelae involving the basal ganglia and died 15 months after OLT. The girl left hospital after 2 months and is presently leading a normal life with almost no dietary protein restriction (40 g protein per day). Urinary urea excretion and daily protein intake increased after liver transplantation. Propionyl- and tiglylglycine disappeared immediately after OLT. Urinary methylcitrate and 3-hydroxypropionate remained at concentrations corresponding to those before OLT. However, the total of all characteristic metabolites of organic acid analysis was reduced to 50-60% of the values before OLT in both patients. Propionylcarnitine was still detected at significant concentrations. Plasma odd-chain fatty acid concentrations decreased continuously after OLT only in the girl's case. Tissue of both transplanted livers showed increased odd-chain fatty acid concentrations 9 and 15 months after OLT, respectively, in both patients. We consider that at present OLT should only be performed in severe forms of propionic acidaemia.

Acidosis↗
PubMed1995

Corneal epithelial fluorescein staining.

BACKGROUND: There is some difference of opinion in the literature about the nature of fluorescein staining of the epithelial surface. Most authors support the view that fluorescein staining is due to drop out of cells and pooling of fluorescein in the footprint. Others believe that fluorescein fills intercellular spaces. Others suggest that cells themselves stain with fluorescein. METHODS: Rabbit corneas were stained with fluorescein and examined with the biomicroscope and later with a higher magnification epifluorescent microscope following excision. RESULTS: Fluorescein staining was shown to be due to staining of individual cells. No evidence was found to support the contention that fluorescein resides in areas of cell drop out, or that staining was due to filling of intercellular spaces. Micropunctate staining is shown to be due to staining of cells in an optimum manner, which is referred to as hyperfluorescence. CONCLUSIONS: The recognition that fluorescein stains cells, even in the case of epithelial abrasion, allows reinterpretation of many staining phenomena, including "salt and pepper" staining.

Animals↗