Biomedical subjects

A Vanderkelen

Publications and source records attributed to A Vanderkelen.

13 recordsLinked to original sources

PubMed2000

Quantitation of Pseudomonas aeruginosa in wound biopsy samples: from bacterial culture to rapid 'real-time' polymerase chain reaction.

STATEMENT OF FINDINGS: We developed a real-time detection (RTD) polymerase chain reaction (PCR) with rapid thermal cycling to detect and quantify Pseudomonas aeruginosa in wound biopsy samples. This method produced a linear quantitative detection range of 7 logs, with a lower detection limit of 103 colony-forming units (CFU)/g tissue or a few copies per reaction. The time from sample collection to result was less than 1h. RTD-PCR has potential for rapid quantitative detection of pathogens in critical care patients, enabling early and individualized treatment.

Bacterial Typing Techniques↗

PubMed2000

Immunoregulatory effector cells in drug-induced toxic epidermal necrolysis.

Toxic epidermal necrolysis (TEN) is a rare drug-induced disease for which the pathomechanism remains poorly understood. The effector cells of epidermal injury in TEN were studied by taking skin biopsies of early lesions in 23 TEN patients and by performing immunohistochemical tests using antibodies to factor XIIIa (type I dendrocytes), L1-protein (mainly Mac 387+ monocytes and macrophages), UCLHI (mainly CD45R0+ T-memory lymphocytes), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNFalpha). Computerized image analysis was used to evaluate the cell density relative to each immunolabeling. A statistical analysis of cellular counts revealed a numeric relation between the cell types in skin with TEN. Factor XIIIa+ dendrocytes were abundant and plump in the dermis, although Mac 387+ macrophages were the most numerous inflammatory cells in the epidermis. Their numbers greatly exceeded those of CD45R0+ T lymphocytes and cells showing immunoreactivity for either IL-6 or TNFalpha. In the epidermis, IL-6+ cells were significantly less numerous than TNFalpha+ cells. No quantitative difference was found between IL-6+ and CD45R0+ cell populations. Correlations were observed between either the numbers of TNFalpha+ cells or Mac 387+ macrophages and CD45R0+ lymphocytes. In the dermis, a significant correlation was also present between the numbers of Mac 387+ and factor XIIIa+ cells. These findings highlight the complex interactions between the inflammatory cells that mediate epidermal damage in skin with TEN. The high density of factor XIIIa+ dendrocytes and Mac 387+ macrophages in lesional skin assigns these cellular populations a prominent role in the pathomechanism of TEN. Despite a lower cell density, CD45RO+ T-memory lymphocytes likely participate in TNFalpha- and IL-6-regulated processes in the epidermis of TEN. TNFalpha seems to be a major cytokine involved in TEN, although a less prominent role can be ascribed to IL-6.

Adolescent↗

PubMed1998

The usefulness of combined high-frequency percussive ventilation during acute respiratory failure after smoke inhalation.

Inhalation injury and bacterial pneumonia represent some of the most important causes of mortality in burn patients. We describe 11 severely burned patients with acute respiratory failure due to inhalation injury who did not respond adequately to conventional respiratory support. High-frequency percussive ventilation (HFPV) is a recent ventilatory mode, which combines the advantages of conventional ventilation with some of those of high-frequency ventilation. Seven patients developed pulmonary infection during the acute phase; one patient died of multiple organ failure on day 25. All the other patients survived; two developed bronchiolitis obliterans symptoms before discharge. No side-effects were noted and haemodynamic tolerance of HFPV was excellent. Our findings suggest that HFPV can improve pulmonary function and gas exchange in these catastrophic pulmonary failures following inhalation injury.

Acute Disease↗

PubMed1997

Analysis of epidemic Pseudomonas aeruginosa isolates by isoelectric focusing of pyoverdine and RAPD-PCR: modern tools for an integrated anti-nosocomial infection strategy in burn wound centres.

The Gram-negative bacterium Pseudomonas aeruginosa is an important life-threatening nosocomial pathogen in burn units. In this study we analysed epidemic P. aeruginosa isolates from patients and their hospital environment using two new molecular techniques in order to establish strain relatedness for epidemiological purposes. One technique was pyoverdine typing by isoelectric focusing (PVD-IEF) and the other was a genomic PCR-based fingerprinting technique called random amplification of polymorphic DNA actually referred to as RAPD-PCR. The described short epidemic (6 weeks) included 37 consecutive isolates from 9 different patients as well as two environmental isolates recovered, at the same time, from one of the hydrotherapy facilities. Only two of the three known pyoverdine types of P. aeruginosa could be found. Type I was absent while type II represented 49 per cent and type III, 51 per cent of the isolates. The two consecutive isolates from the environment were both of type III. The RAPD-PCR fingerprinting discriminated four patterns. Profile 1 represented 60 per cent; profile 2, 34 per cent; and profiles 3 and 4 only 3 per cent of the isolates respectively. The environmental isolates also had a RAPD-PCR 1 profile, arguing for the hydrotherapy facility as a possible contamination source. Prompt measures could prevent an outbreak. The study demonstrates the applicability of the techniques in a routine microbiology lab as well as their usefulness, in combination with other techniques, in the fight against nosocomial infections, which are so critical in burn units. Both techniques showed undoubtable evidence of the occurrence of polymicrobial infection of individual patients by P. aeruginosa species. Meanwhile pyoverdine typing by IEF seems suited to studying more profoundly the role of pyoverdines in burns.

Bacterial Typing Techniques↗

PubMed1997

HIV transmission by transplantation of allograft skin: a review of the literature.

The fear of human immunodeficiency virus (HIV) transmission by means of allograft skin has led to a cautious approach to allograft donor selection. However, no irrefutable diagnostic test exists to determine the possible presence of HIV at the time of donation. In order to find ways of improving HIV donor screening practices for skin banks, we review the presence of HIV in human skin, explore the possible transmission of HIV by transplantation of human allograft skin, and discuss the reliability of existing HIV tests. The use of the polymerase chain reaction (PCR) as a sensitive detection system for HIV infection of skin biopsies, in combination with conventional routine HIV blood screening tests; could lower the risk of transmitting HIV to severely burned patients.

Guidelines as Topic↗

PubMed1997

Direct detection and identification of Pseudomonas aeruginosa in clinical samples such as skin biopsy specimens and expectorations by multiplex PCR based on two outer membrane lipoprotein genes, oprI and oprL.

A multiplex PCR test based on the simultaneous amplification of two lipoprotein genes, oprI and oprL, was designed and evaluated for its ability to directly detect fluorescent pseudomonads (amplification of oprI open reading frame, 249 bp) and Pseudomonas aeruginosa (amplification of oprL open reading frame, 504 bp) in clinical material. A collection of reference strains including 20 different species of fluorescent pseudomonads was tested. Positive PCR results for both genes were observed only for P. aeruginosa isolates (n = 150), including strains of clinical and environmental origin, while only one gene, oprI, was amplified from the other fluorescent pseudomonads. All other bacteria tested (n = 15) were negative by the amplification test. The lower detection level for P. aeruginosa was estimated to be 10(2) cells/ml. Preliminary evaluation on testing skin biopsy specimens from patients with burns (n = 14) and sputum samples from cystic fibrosis patients (n = 49) and other patients (n = 19) showed 100% sensitivity and 74% specificity in comparison with culture. This multiplex PCR assay appears promising for the rapid and sensitive detection of P. aeruginosa in clinical specimens. Further evaluation of its specificity in longitudinal clinical studies is warranted.

Bacterial Outer Membrane Proteins↗

PubMed1996

Hyperbaric oxygen therapy and piracetam decrease the early extension of deep partial-thickness burns.

During the first 24 h, a progression of the burn wound in histological depth or extension is often noted. This can only partially be prevented by the routinely used protocols of fluid resuscitation and burn wound dressing. In a rat model of 5% TBSA burn, hyperbaric oxygen therapy (HBOT) and piracetam were evaluated for their ability to further prevent this early deepening of the burn wound. After infliction of the burn wound, the animals were treated with an accepted basic burn wound treatment consisting of mafenide 10% solution humid dressings. They were then randomized into three groups: a control group (n = 10), receiving no other treatment, a HBOT group (n = 17), receiving 60 min of HBOT (203 kPa) twice daily, and a piracetam group (n = 19), receiving piracetam (200 mg/kg IM) twice daily. On the third day of treatment, the entire burn wound was exised and examined histologically. It was found that both HBOT and piracetam had statistically significant effects on the preservation of epidermal basal membrane (P < 0.001 and P < 0.01, respectively). HBOT, but not piracetam, further had significant effects on the destruction of skin appendages (P < or = 0.05 and P > 0.05, respectively) and on the degree of subepidermal inflammation, as measured by leucocyte infiltration (P < 0.001 and P > 0.05, respectively). Furthermore, the HBOT group showed significantly less leucocyte infiltration than the piracetam group (P < 0.01). It was concluded that, although the clinical importance of the small effects on skin appendage and basal membrane preservation may be questionable, the effect on subepidermal leucocyte infiltration is striking and warrants further investigation of the anti-inflammatory effects of HBOT and possibly piracetam.

Animals↗

PubMed1996

Nitric oxide production is increased in patients after burn injury.

OBJECTIVE: Human burn injury is associated with an inflammatory response and related hyperdynamic cardiovascular profile. Increased production of nitric oxide (NO), a potent endogenous vasodilator, has been reported in patients with inflammatory states, including sepsis, but not after trauma other than burns. We studied whether plasma levels of the stable byproducts of NO, nitrite (NO2-) and nitrate (NO3-), are increased in burn patients. DESIGN: Prospective controlled study. PATIENTS AND METHODS: In consecutive patients admitted to the intensive care unit of the burn center at the Queen Astrid Military Hospital in Brussels, plasma was drawn daily from day 1 to day 5 postadmission for determination of NO2-/NO3- levels (Griess' reaction). In a control group of nonseptic inpatients from the department of neurology in Erasme University Hospital who were matched for nutrition (30 to 40 kcal/kg/day of a standard enteral solution), plasma was drawn once for NO2-/NO3- determination. MEASUREMENTS AND MAIN RESULTS: The burn group included 16 patients (age 35 +/- 18 years, total burn surface area (TBSA) 37 +/- 19%) and the control group included six patients (age 64 +/- 18 years). For each comparison between the groups, NO2-/NO3- plasma levels were higher in those patients with burns than in the control group. In the burn group, there was no correlation between NO2-/NO3- plasma levels and TBSA, age, TBSA x age, blood pressure or time. However, in a subgroup of five burned patients who became septic during the study period, NO2-/NO3- plasma levels were slightly higher than in the non-infected patients (177 +/- 131 vs. 83 +/- 48 micromoles/L, NS). CONCLUSION: Human burn injury is associated with an increase in NO production. In this small-size study, NO production was not proportional to burn area, and seemed to be further enhanced in septic patients.

Adolescent↗

PubMed1996

Lyophilized keratinocyte cell lysates contain multiple mitogenic activities and stimulate closure of meshed skin autograft-covered burn wounds with efficiency similar to that of fresh allogeneic keratinocyte cultures.

For several years, grafting with allogeneic keratinocyte cultures has been used successfully as a wound-healing therapy both by us and by many other groups. Since their postgrafting survival time is limited, the effect of these cultures is generally explained by the production of wound repair-stimulating factors that promote proliferation and migration of resident cells. In this study we show that lysates of cultured keratinocytes contain mitogenic activity for keratinocytes, endothelial cells, and fibroblasts. In addition, the lysates inhibit the contraction of collagen gels by human skin fibroblasts. On the basis of these observations and of in vivo data obtained by ourselves and others, we have evaluated the effect of total keratinocyte lysates on the healing of meshed skin autograft-covered burn wounds. Twenty burn wounds were tangentially excised and autografted with one to three meshed conventional skin transplants. An area treated with a gel containing lysated keratinocyte cultures was compared with an area treated with placebo-gel in terms of epithelialization on day 5. In six patients an additional fresh keratinocyte alloculture was applied as a positive control. Results indicate that the newly formed epithelium (difference between percentage of epithelialization on day 5 and on day 0) was 31.1 percent in the treated area compared with 16.5 percent in the placebo area. This result is comparable with the value obtained by treatment with fresh keratinocyte allocultures, namely, 33.8 percent. These figures show a twofold stimulation of epithelialization.

Adolescent↗

PubMed1995

Burns induced by plants.

Plants of the family Umbelliferae are known to cause a phytophotodermatitis due to a phototoxic reaction caused by furocoumarin (psoralens) and simultaneous exposure to sunlight. We report four patients with partial skin thickness burns, induced by this phototoxic reaction. One occurred after contact with parsley (Apium petroselinum) and three others after contact with giant hogweed (Heracleum mantegazzianum) and simultaneous exposure to sunlight.

Adolescent↗

PubMed1994

Macrophages and tumor necrosis factor alpha in toxic epidermal necrolysis.

BACKGROUND: We studied the immunopathologic characteristics of five cases of toxic epidermal necrolysis by using a large panel of antibodies. OBSERVATIONS: The pattern and amount of the inflammatory cell infiltrate varied according to the stage of the disease. The main constant feature was the prominent involvement of the monocyte-macrophage lineage, including factor XIIIa+HLA-DR+ dendrocytes and CD68+ Mac 387+ macrophages, before and during the epidermal necrosis. The number of CD4+ and CD8+ lymphocytes was comparatively small. This was associated with a dense labeling of the epidermis for tumor necrosis factor alpha. CONCLUSIONS: Cells of the monocyte-macrophage lineage largely outnumber lymphocytes in the lesions of toxic epidermal necrolysis. Tumor necrosis factor alpha is likely a major cytokine that is responsible for necrosis.

Adolescent↗

PubMedDate not supplied

Cultured allogeneic keratinocyte sheets accelerate healing compared to Op-site treatment of donor sites in burns.

Donor site treatment is a crucial issue in the treatment of extensive burns. In this single-blind, randomized study treatment of donor sites with a polyurethane dressing, Op-Site (Smith & Nephew, York, U.K.) is compared to treatment with allogeneic cultured keratinocyte sheets. Results show a mean healing time of 6.7 days with use of cultured keratinocyte sheets compared to mean healing time of 13.6 days with Op-Site treatment. Also, improvement in the comfort of patients as the result of less exudate formation and pain attenuation was noted.

Adolescent↗

PubMedDate not supplied

Enhancement of healing of mesh grafts with autologous keratinocytes.

Cultured epithelium prepared from epidermal cells may spread to cover large wounds and may also stimulate the growth of islands of intact cells. Autologous keratinocytes have been used in two cases to enhance the healing of mesh grafts laid on large surgical wounds.

Cells, Cultured↗