Hydroconductive and silver-impregnated foam dressings: a comparison.

OBJECTIVE: As the number of commercially available wound dressings is increasing rapidly, it is important for clinicians to understand the strengths and limitations of each and to recognise relationships between wound type and dressing properties to obtain optimal healing results. Our aim is to test the antimicrobial activity of two dressings. METHOD: A hydroconductive (HC) dressing and a silver-impregnated foam (SIF) dressing were compared for their potential to reduce the levels meticillin-resistant Staphylococcus aureus (MRSA). We also assessed MRSA-derived biologically active components in liquid or agar matrices, simplified models for heavily exuding or dry wounds respectively, and in an in vivo animal model with MRSA infected wounds. RESULTS: In the agar model (dry wounds) both dressings showed a strong reduction in MRSA activities within 24 hours post-application. The antibacterial effects of the SIF dressing were more pronounced in the liquid model, however, at an increasing cytotoxic cost. In agreement with these in vitro results, assessment of dressings using an MRSA-infected wound in an rat model showed a decrease in MRSA which was significant 7 days post-burn and inoculation, with more compromised viability of MRSA. Dressings showed a similar capability to reduced and eliminate toxic shock syndrome toxin (TSST-1) at day 7 post-burn in the animal model but not at day 4, where the SIF dressing was more potent Conclusion: These results confirm the advantages of using silver in reducing bacterial load in wound treatment, except for conditions of highly exuding wounds where the cytotoxic properties of silver may offset these advantages and HC dressing use is more suitable.

A Translational Animal Model for Scar Compression Therapy Using an Automated Pressure Delivery System.

BACKGROUND: Pressure therapy has been used to prevent and treat hypertrophic scars following cutaneous injury despite the limited understanding of its mechanism of action and lack of established animal model to optimize its usage. OBJECTIVES: The aim of this work was to test and characterize a novel automated pressure delivery system designed to deliver steady and controllable pressure in a red Duroc swine hypertrophic scar model. METHODS: Excisional wounds were created by dermatome on 6 red Duroc pigs and allowed to scar while assessed weekly via gross visual inspection, laser Doppler imaging, and biopsy. A portable novel automated pressure delivery system was mounted on developing scars (n = 6) for 2 weeks. RESULTS: The device maintained a pressure range of 30 ± 4 mm Hg for more than 90% of the 2-week treatment period. Pressure readings outside this designated range were attributed to normal animal behavior and responses to healing progression. Gross scar examination by the Vancouver Scar Scale showed significant and sustained (>4 weeks) improvement in pressure-treated scars (P < .05). Histological examination of pressure-treated scars showed a significant decrease in dermal thickness compared with other groups (P < .05). Pressure-treated scars also showed increased perfusion by laser Doppler imaging during the treatment period compared with sham-treated and untreated scars (P < .05). Cellular quantification showed differential changes among treatment groups. CONCLUSION: These results illustrate the applications of this technology in hypertrophic scar Duroc swine model and the evaluation and optimization of pressure therapy in wound-healing and hypertrophic scar management.

[Atypical progressive multifocal leukoencephalopathy (PML) in a patient with pulmonary sarcoidosis]. / Leucoencéphalopathie multifocale progressive atypique chez un patient atteint de sarcoïdose médiastinopulmonaire.

INTRODUCTION: Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of central nervous system due to the JC virus. PML generally occurs in immunocompromised hosts and has a fatal outcome. OBSERVATION: We report a case of an atypical PML in a patient with pulmonary sarcoidosis: MRI showed multifocal and punctate contrast enhancements. The diagnostic was made by brain biopsy. CONCLUSION: The pathophysiology of this association is probably related to the immunodepression induced by sarcoidosis.

[Intracranial localization revealing Hodgkin's disease]. / Lésion intracrânienne révélatrice d'une maladie de Hodgkin.

The central nervous system's (CNS) involvement is uncommon in Hodgkin's disease (HD) and usually occurs in patients with relapsing disease many years after the initial diagnosis. An isolated involvement of the CNS is extremely rare and therefore, difficult to diagnosis. We report the case of a 27-year-old woman with seizure and a left cerebrodural mass on the cerebral imaging; secondarily, she developed cervical lymph node swelling; histological examination of the node revealed HD of the nodular sclerosis type. The dural lesion resolved after chemotherapy for HD.

[Listeria monocytogenes encephalitis revealed by left progressive hemiparesis]. / Hémiparésie d'installation progressive révélant une encéphalite à listéria monocytogènes.

INTRODUCTION: Central nervous system listeriosis is a diagnostic and therapeutic challenge for the clinician. CASE REPORT: We report the case of a 66-year-old woman who was admitted for a left progressive hemiparesis associated with headaches. She was treated for one year by immunosuppressive drugs for vulgaris pemphigus. At the time of admission, examination revealed left hemiparesis without fever, and a computed tomography brain scan demonstrated a focal lesion in the right frontal lobe. Blood analyses were normal. Two days after, she suddenly developed fever (40 degrees C), and aggravation of her motor deficit followed by partial motor seizures. The cerebrospinal fluid was normal. Treatment with amoxicillin (3g IV q6h), cefotaxim, gentamycin (120mg IV q12h) and aciclovir was started empirically. The brain MRI without gadolinium displayed infiltrative lesions in the right hemisphere and in the mildbrain. The blood culture grew Listeria monocytogenes. The antimicrobial regimen was changed to amoxicillin for seven weeks and gentamicin for the first ten days. Four days after beginning the antimicrobial regimen, the brain MRI with gadolinium displayed several abscesses measuring less than one cm diameter. The clinical and imaging outcome excellent. CONCLUSION: Meningitis is by far the most central nervous system listeriosis. In our patient, the diagnosis of listeria monocytogenes encephalitis was established on the basis of positive blood cultures, as such patients do not have sterile cerebrospinal fluid.

Plasmodium falciparum cytoadherence to human placenta: evaluation of hyaluronic acid and chondroitin 4-sulfate for binding of infected erythrocytes.

Chondroitin 4-sulfate (C4S) is known to mediate the adherence of Plasmodium falciparum infected red blood cells (IRBCs) to human placenta. Recently, hyaluronic acid (HA) has also been reported to bind IRBCs, and HA has been suggested as an additional receptor for the sequestration of IRBCs in the placenta. In this study, we assessed the adherence of 3D7 parasite strain, which has been reported to bind both C4S and HA, using highly purified clinical grade rooster comb HA, Streptococcus HA, several preparations of human umbilical cord HA (hucHA), and bovine vitreous humor HA (bvhHA). While all hucHA preparations and bvhHA bound with moderate to high density to IRBCs, the rooster comb and bacterial HAs did not bind IRBCs. IRBCs binding to the hucHA and bvhHA could be abolished by pretreatment with testicular hyaluronidase but not with Streptomyces hyalurolyticus hyaluronidase, suggesting that IRBC binding to hucHA and bvhHA was due to chondroitin sulfate (CS) contaminants in HAs. Compositional analysis confirmed the presence of CS in both hucHA and bvhHA. The CSs present in these commercial hucHA and bvhHA samples were isolated, characterized, and studied for their ability to bind IRBCs. The data suggested that IRBC adherence to hucHA and bvhHA was mediated by the CS present in these samples. However, our data did not exclude the possibility of a minor population of distinct parasite subtype adhering to HA and further studies using pure HA conjugated to proteins or lipids and placental parasite isolates should clarify whether HA is an in vivo receptor for IRBC adherence.

Characterization of proteoglycans of human placenta and identification of unique chondroitin sulfate proteoglycans of the intervillous spaces that mediate the adherence of Plasmodium falciparum-infected erythrocytes to the placenta.

In pregnant women infected with Plasmodium falciparum, the infected red blood cells (IRBCs) selectively accumulate in the intervillous spaces of placenta, leading to poor fetal outcome and severe health complications in the mother. Although chondroitin 4-sulfate is known to mediate IRBC adherence to placenta, the natural receptor has not been identified. In the present study, the chondroitin sulfate proteoglycans (CSPGs) of human placenta were purified and structurally characterized, and adherence of IRBCs to these CSPGs investigated. The data indicate that the placenta contains three distinct types of CSPGs: significant quantities of uniquely low sulfated, extracellular CSPGs localized in the intervillous spaces, minor amounts of two cell-associated CSPGs, and major amounts of dermatan sulfate-like CSPGs of the fibrous tissue. Of the various CSPGs isolated from the placenta, the low sulfated CSPGs of the intervillous spaces most efficiently bind IRBCs. Based on IRBC adherence capacities and localization patterns of various CSPGs, we conclude that the CSPGs of the intervillous spaces are the receptors for placental IRBC adherence. The identification and characterization of these CSPGs provide a valuable tool for understanding the precise molecular interactions involved in placental IRBC adherence and for the development of therapeutic strategies for maternal malaria. In the accompanying paper (Alkhalil, A., Achur, R. N., Valiyaveettil, M., Ockenhouse, C. F., and Gowda, D. C. (2000) J. Biol. Chem. 275, 40357-40364), we report the structural requirements for the IRBC adherence.

Structural requirements for the adherence of Plasmodium falciparum-infected erythrocytes to chondroitin sulfate proteoglycans of human placenta.

Plasmodium falciparum infection during pregnancy results in the accumulation of infected red blood cells (IRBCs) in the placenta, leading to poor pregnancy outcome. In the preceding paper (Achur, R. N., Valiyaveettil, M., Alkhalil, A., Ockenhouse, C. F., and Gowda, D. C. (2000) J. Biol. Chem. 275, 40344-40356), we reported that unusually low sulfated chondroitin sulfate proteoglycans (CSPGs) in the intervillous spaces of the placenta mediate the IRBC adherence. In this study, we report the structural requirements for the adherence and the minimum chondroitin 4-sulfate (C4S) structural motif that supports IRBC adherence. Partially sulfated C4Ss with varying sulfate contents were prepared by solvolytic desulfation of a fully sulfated C4S. These and other nonmodified C4Ss, with different proportions of 4-, 6-, and nonsulfated disaccharide repeats, were analyzed for inhibition of IRBC adherence to the placental CSPG. C4Ss containing 30-50% 4-sulfated and 50-70% nonsulfated disaccharide repeats efficiently inhibited IRBC adherence; C6S had no inhibitory activity. Oligosaccharides of varying sizes were prepared by the partial depolymerization of C4Ss containing varying levels of 4-sulfation, and their ability to inhibit the IRBC adherence was studied. Oligosaccharides with six or more disaccharide repeats inhibited IRBC adherence to the same level as that of the intact C4Ss, indicating that a dodecasaccharide is the minimum structural motif required for optimal IRBC adherence. Of the C4S dodecasaccharides, only those with two or three sulfate groups per molecule showed maximum IRBC inhibition. These data define the structural requirements for the IRBC adherence to placental CSPGs with implications for the development of therapeutics for maternal malaria.