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Biomedical subjects

J Guilbaud

Publications and source records attributed to J Guilbaud.

At least 19 recordsLinked to original sources
PubMed1998

Advantage of the presence of living dermal fibroblasts within in vitro reconstructed skin for grafting in humans.

Methods for serial cultivation of human keratinocytes can provide large quantities of epidermal cells, which have the potential of restoring the vital barrier function of the epidermis in extensive skin defects such as burns. To investigate the value of combining an epidermis with a dermal component, fibroblasts originated from the superficial dermis were used to seed a collagen lattice as described by E. Bell (dermal equivalent). Beginning in 1981, we grafted 18 patients (burns and giant nevi) using 35 grafts 10 x 10 cm in size. In the course of this work, the original technique was modified and improved as experience was gained. We began by using small skin biopsy samples as a source of keratinocytes cultured on a dermal equivalent before grafting in a one-step procedure, but this gave poor cosmetic results, because of a nonhomogeneous epidermalization. We then chose to cover the graft bed using a two-step procedure. The first step consisted of grafting a dermal equivalent to provide a dermal fibroblast-seeded substrate for subsequent in vivo epidermalization by cultured epidermal sheets. Whatever the epidermalization technique used, a living dermal equivalent applied to the graft bed was found to reduce pain, to provide good hemostasis, and to improve the mechanical and cosmetic properties of the graft. A normal undulating dermal-epidermal junction reappeared by 3 to 4 months after grafting and elastic fibers were detectable 6 to 9 months after grafting. As a result of the biosynthesis of these products, the suppleness (e.g., elasticity) of the grafts was closer to that of normal skin than the cicatricial skin usually obtained with epidermal sheets grafted without the presence of living dermal cells. This rapid improvement of the mechanical properties of the graft could be attributed to the presence of fibroblasts cultured from the dermis and seeded into the collagen matrix.

Adult↗
PubMed1993

High serum procalcitonin concentrations in patients with sepsis and infection.

High concentrations of calcitonin-like immunoreactivity have been found in the blood of patients with various extrathyroid diseases. By means of a monoclonal immunoradiometric assay for calcitonin precursors, we have measured serum concentrations of procalcitonin in patients with various bacterial and viral infections. 79 children (newborn to age 12 years) in hospital with suspected infections were investigated prospectively. 19 patients with severe bacterial infections had very high serum concentrations of procalcitonin at diagnosis (range 6-53 ng/mL) in comparison with 21 children found to have no signs of infection (baseline concentrations < 0.1 ng/mL). Serum procalcitonin values decreased rapidly during antibiotic therapy. 11 patients with peripheral bacterial colonisation or local infections without invasive sepsis and 18 (86%) of 21 patients with viral infections had concentrations within or slightly above the normal range (0.1-1.5 ng/mL). Among 9 severely burned patients studied in an intensive care unit, the post-traumatic course of procalcitonin concentrations (range 0.1-120 ng/mL) was closely related to infectious complications and acute septic episodes. Concentrations of mature calcitonin were normal in all subjects, whatever procalcitonin concentrations were found. Concentrations of a substance immunologically identical to procalcitonin are raised during septic conditions. Serum concentrations seem to be correlated with the severity of microbial invasion.

Bacterial Infections↗
PubMed1992

European comparative clinical study of Inerpan: a new wound dressing in treatment of partial skin thickness burns.

Eleven European burns centres in five countries (Belgium, England, Germany, Italy, Switzerland) participated in a prospective, randomized clinical trial comparing a new wound dressing Inerpan with conventional dressings such as petroleum jelly gauze, petroleum jelly gauze with antibiotics and silver sulphadiazine cream. The indication was partial skin thickness burns and 62 patients were included. In each patient, two similar lesions (with respect to depth and surface area) were compared, one being treated with Inerpan, the other one with a control dressing. The following parameters were studied: healing time, quality of healing, intensity of pain, local tolerance and frequency of dressing changes. Analysis of the results showed that Inerpan-treated sites healed faster than conventional ones, and were associated with a highly significant reduction of pain. The frequency of dressing changes was greatly reduced and the local tolerance was good.

Adolescent↗
PubMed1991

Effect of platelet-activating factor on tumor necrosis factor-induced superoxide generation from human neutrophils. Possible involvement of G proteins.

The effect of platelet-activating factor (PAF) and of two specific PAF antagonists on tumor necrosis factor (TNF) induced superoxide production by human polymorphonuclear neutrophils (PMN) was examined. PAF alone (0.1 pM to 0.1 nM) failed to evoke superoxide production; however, when PAF was added for 10 min to cells upon prior incubation with 10 ng/mL TNF for 50 min, superoxide production was significantly enhanced as compared to that induced by TNF alone. Maximum amplification (+30%) was obtained with 10 pM PAF; however, the effect was completely abolished by two structurally unrelated PAF antagonists, BN 52021 and BN 52111. The antagonists also decreased by 25% the superoxide production elicited solely by TNF, implicating the involvement of endogenous PAF in this process. Pretreatment of the PMN with either pertussis or cholera toxin attenuated the PAF amplified superoxide production in TNF stimulated cells, suggesting that G proteins sensitive to these toxins may be involved in the mechanisms controlling amplification.

Cholera Toxin↗
PubMed1990

Tumor necrosis factor alpha 'primes' the platelet-activating factor-induced superoxide production by human neutrophils: possible involvement of G proteins.

It has recently been demonstrated that very low concentrations of platelet-activating factor (PAF) and various cytokines can prime human neutrophils (PMN) to respond in an enhanced manner to subsequent agonistic stimulation. We were interested to ascertain whether superoxide generation by human PMN could be amplified by PAF following initial stimulation with tumor necrosis factor (TNF) and the effect of cholera and pertussis toxin on this process. PAF alone (0.1 pM-0.1 nM) failed to evoke any superoxide production; however, when PAF was added for 10 min to cells previously incubated for 50 min with 10 ng/ml TNF, superoxide production was significantly enhanced relative to that induced by TNF alone. Maximum amplification (+30%) was obtained with 10(-12) M PAF, this effect being completely abolished by BN 52021 and BN 52111, two structurally unrelated PAF antagonists. The PAF antagonists also decreased by 25% the superoxide production elicited solely by TNF, indicating that TNF-induced superoxide generation is partially mediated by a mechanism involving endogenous PAF. Pretreatment of the PMN with pertussis or cholera toxin reduced the amplification of superoxide production induced by PAF in TNF-stimulated PMN, implicating pertussis and cholera toxin-sensitive G-proteins in the amplification process.

Cholera Toxin↗
PubMed1989

[Burns and pregnancy. A case of severe burn occurring at the beginning of pregnancy. Maternal and fetal survival].

The authors report a case of a severe thermal burn (70% of the surface of the body) in a pregnant woman who had 15 weeks amenorrhoea. The survival of the mother and the continuation of the pregnancy to term allowed a normal live baby to be born. As far as the authors know this is the fourth case history of a severe (more than 60% of the body) burn published occurring in the first trimester of pregnancy and carried through successfully to term. A study of the literature has shown that the physiopathological results of severe burns do explain the usually poor prognosis for mother and fetus. Large quantities of prostaglandins are released into the circulation of the mother because of the thermal insult to tissues and because of the infection that usually accompanies such burns. These prostaglandins can stimulate the myometrium, which gives rise to fatal obstetric complications. The urgent acute treatment for a severe burn in a pregnant woman, which should preferably be carried out in a special centre, consists in water and electrolyte resuscitation, assisted respiration and prevention of bacterial contamination. These measures are just as important for the fetus. At the same time obstetric care should be started. Good collaboration between the obstetricians and those who carry out the resuscitation all bring about the measures that are needed to allow the mother and fetus to survive.

Adult↗
PubMed1985

Leukocytic functions in burn-injured patients.

Anergy associated with an increase in suppressor helper T cell (Tc) ratio and a decrease in natural killer (NK) is one main cause of death following thermal injury (Tl). Recently, in vitro studies have shown that LTB4 can induce human Tc to exert suppressor cell activity, and incubation of lymphocytes with LTB4 for 24 hours significantly suppressed NK cell activity. Thus, we undertook an investigation of both AA metabolism and immunologic response in 20 patients who suffered 40-90% total body surface area (TBSA) burns. Cyclooxygenase (CO:RIA) and lipoxygenase (LO;HPLC det.) metabolites and superoxide (O2 X-) production were measured in stimulated polymorphonuclear cells (PMNL) (A 23187 +/- AA for icosanoid release; phorbol myristate acetate for O2 X-production). Lyso-paf-acether (P-LPA) was measured in plasma samples. Ca2+-dependent K+permeability in PMNL was measured by the cell K+ release induced by A 23187. Tc and Tc subsets were determined using monoclonal antibodies (OKT3+, OKT4+ and OKT8+). A biphasic sequential release of the different substances (leukocytic icosanoids and O2 X-) was monitored: increase (approximately 36-48 h after Tl) and decrease (greater than or equal to 72 h after Tl). The increase in AA stimulation was more transient than that of O2 X -. The decline in the release of AA metabolites and O2 X-production was associated with the anergic phase (decrease OKT4+/OKT8+ ratio) and with the clinical outcome of the patients. The decrease in LTB4 and other LO metabolites could explain the impairment of neutrophil chemotaxis. Ca2+-dependent K+ permeability increased early up to 2 or 3 times normal. In order to go further with the mechanism of inhibition of LTB4 and O X-release, the effect of Tl plasma was assayed on normal leukocytes: a 10 min incubation with such plasma was sufficient to abolish LTB4 secretion. A less important inhibition was observed with O2 X-release (-32%) and Ca2+-dependent K+ permeability (-30%). Plasma inhibition seems to be due to a thermolabile factor(s) [protein(s): "suppressive factor(s) of membrane activation "SFMA] which is (are) under active investigation using gel-filtration chromatography and fast protein liquid chromatography (FPLC). Among the SFMAs, certain acute phase proteins could play a key role: i.e., incubation (10 min) of normal PMNL with ceruloplasmin (1 mg/ml) abolished LO products and O X 2-release.

Adolescent↗
PubMed1984

[Role of Pseudomonas aeruginosa in infection in burn patients].

The regular finding of Pseudomonas aeruginosa in Burns Units has always been a source of worries. Following a brief review of the natural history of this micro-organism, the authors examine all possible therapeutic measures. They underline the importance of measures aimed at controlling environmental and epidemiological factors and at improving surveillance. These measures, together with baths, topical applications of antibacterial agents and prophylactic vaccination and serotherapy tend to circumscribe the infection. When therapeutic measures are not as effective as expected and natural defences collapse, sepsis develops with clinical features that male diagnosis uneasy. The conditions in which antibiotics are given are peculiar in burned patients, and the therapeutic approach to Pseudomonas infections is particularly difficult in such cases.

Anti-Bacterial Agents↗