Hydrogen Peroxide Generation of Copper/Ascorbate Formulations on Cotton: Effect on Antibacterial and Fibroblast Activity for Wound Healing Application.

Greige cotton (unbleached cotton) is an intact plant fiber that retains much of the outer cotton fiber layers. These layers contain pectin, peroxidases, and trace metals that are associated with hydrogen peroxide (H2O2) generation during cotton fiber development. When greige cotton is subjected to a nonwoven hydroentanglement process, components of the outer cotton fiber layers are retained. When hydrated, this fabric can generate H2O2 (5⁻50 micromolar). This range has been characterized as inducing accelerated wound healing associated with enhanced cell signaling and the proliferation of cells vital to wound restoration. On the other hand, H2O2 levels above 50 micromolar have been associated with bacteriostatic activity. Here, we report the preparation and hydrogen peroxide activity of copper/ascorbate formulations, both as adsorbed and in situ synthesized analogs on cotton. The cooper/ascorbate-cotton formulations were designed with the goal of modulating hydrogen peroxide levels within functional ranges beneficial to wound healing. The cotton/copper formulation analogs were prepared on nonwoven unbleached cotton and characterized with cotton impregnation titers of 3⁻14 mg copper per gram of cotton. The copper/ascorbate cotton analog formulations were characterized spectroscopically, and the copper titer was quantified with ICP analysis and probed for peroxide production through assessment with Amplex Red. All analogs demonstrated antibacterial activity. Notably, the treatment of unbleached cotton with low levels of ascorbate (~2 mg/g cotton) resulted in a 99 percent reduction in Klebsiella pneumoniae and Staphylococcus aureus. In situ synthesized copper/ascorbate nanoparticles retained activity and did not leach out upon prolonged suspension in an aqueous environment. An assessment of H2O2 effects on fibroblast proliferation are discussed in light of the copper/cotton analogs and wound healing.

Vitamin C promotes wound healing through novel pleiotropic mechanisms.

Vitamin C (VitC) or ascorbic acid (AscA), a cofactor for collagen synthesis and a primary antioxidant, is rapidly consumed post-wounding. Parenteral VitC administration suppresses pro-inflammatory responses while promoting anti-inflammatory and pro-resolution effects in human/murine sepsis. We hypothesised that VitC could promote wound healing by altering the inflammatory, proliferative and remodelling phases of wound healing. Mice unable to synthesise VitC (Gulo(-/-) ) were used in this study. VitC was provided in the water (sufficient), withheld from another group (deficient) and supplemented by daily intra-peritoneal infusion (200 mg/kg, deficient + AscA) in a third group. Full thickness excisional wounds (6 mm) were created and tissue collected on days 7 and 14 for histology, quantitative polymerase chain reaction (qPCR) and Western blotting. Human neonatal dermal fibroblasts (HnDFs) were used to assess effects of In conclusion, VitC favorably on proliferation. Histological analysis showed improved wound matrix deposition and organisation in sufficient and deficient +AscA mice. Wounds from VitC sufficient and deficient + AscA mice had reduced expression of pro-inflammatory mediators and higher expression of wound healing mediators. Supplementation of HnDF with AscA induced the expression of self-renewal genes and promoted fibroblast proliferation. VitC favourably impacts the spatiotemporal expression of transcripts associated with early resolution of inflammation and tissue remodelling.

Preconditioning with cobalt protoporphyrin protects human gastric mucosal cells from deoxycholate-induced apoptosis.

In this study, a known inducer of heme oxygenase-1 (HO-1) expression, cobalt protoporphyrin, and the introduction of a recombinant plasmid expressing HO-1 were examined for their ability to protect gastric epithelial cells from deoxycholate-induced injury. Physiologic levels of the secondary bile salt induce apoptosis in a human gastric adenocarcinoma mucosal cell line. Cobalt protoporphyrin induced expression of HO-1 protein with maximal levels attaining a plateau at 48 hours. Pretreatment with cobalt protoporphyrin before challenge with 200 µM deoxycholate inhibited cell death, DNA fragmentation, the appearance of cytosolic nucleosomes, and cleavage of caspase-3, caspase-9, and poly-(ADP-ribose) polymerase 1. Similarly, expression of HO-1 by introduction of a recombinant plasmid also showed a resistance to deoxycholate-induced apoptosis. These results implicate a possible role for HO-1 in modulating apoptosis in gastric epithelial cells.

Wound fluids: a window into the wound environment?

Wound healing of the skin is a complex biologic process involving temporal interactions between numerous types of cells, extracellular matrix molecules, and soluble factors. The process of repair can be viewed as involving 3 or 4 phases: homeostasis, inflammation, synthesis, and remodeling. These phases occur at different times and differ in their cellular, biochemical, and physiologic requirements. Disruption of one or more of these interactions can significantly interfere with the repair process. Such comorbidities as age, nutrition, immune status, and underlying disease status (eg, diabetes or venous stasis) contribute additional intricacy to the repair process. Because of this complexity, care of chronic wounds remains highly individualized, and it should not come as a surprise that treatment of these wounds as a group with single target therapies have met with only modest success. A major hurdle in the progression toward improved treatment regimens has been the lack of objective biochemical and physiological landmarks that can be used to assess wound status. Collection and biochemical characterization of wound fluids presents the opportunity to noninvasively obtain information reflecting the status of the wound and of specific biomarkers. This review discusses the collection of wound fluid and highlights biomarkers that may be useful to this end.

Physiologic concentrations of leptin increase collagen production by non-immortalized human hepatic stellate cells.

The effects of leptin, in concentrations seen in obesity, on collagen production and turnover in non-immortalized human hepatic stellate cell (HSC), were unknown. The profibrogenic effects of leptin in these cells were studied. Hepatic stellate cells were obtained from resected livers. Collagen I/III gene expression and protein production were measured by quantitative real-time polymerase chain reaction and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. The signal transduction pathways involved were evaluated by specific blockers of the phosphatidylinositol 3-kinase (PI3K), mitogen-activated protein kinase kinase (MEK), and Janus kinase 2 (JAK2). The effects on matrix metalloproteinase 1 (MMP-1) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were assessed by their gene transcript levels, collagenolytic activity of cell culture supernatants, and MMP-1 protein levels. At concentrations seen in nonobese individuals ([leptin] < 10 ng/mL), leptin did not affect collagen production. At concentrations seen in obesity (30-50 ng/mL), leptin increased collagen I and III messenger RNA (mRNA) transcript levels by 286% +/- 55% (P < .001) and 167% +/- 62% (P < .007) and protein production by 45.8% +/- .02% and 84.39% +/- .01%, respectively. These effects were blocked by JAK2 inhibition as well as PI3K inhibition. Although MEK inhibition blocked leptin-induced procollagen I and III mRNA levels, there were no significant effects on collagen I and III protein levels. Leptin (10-50 ng/mL) had no significant effects on MMP-1 or TIMP-1 mRNA levels, collagenolytic activity, or MMP-1 protein levels. In conclusion, leptin, at levels seen in obese individuals, produces an increase in collagen production by HSC acting through the JAK and PI3K pathways. At these concentrations, leptin does not affect MMP-1 or TIMP-1 expression or collagenolytic activity of HSC.

Hyaluronan in human acute and chronic dermal wounds.

There is growing interest in the relationship of hyaluronan and inflammation in a number of physiologic processes including wound healing. The objective of this study was to make a quantitative comparison of inflammation and hyaluronan expression in human normal healing open wounds and in pressure ulcers. Using an open dermal wound model, myeloperoxidase activity was found to peak at day 3. Hyaluronan levels showed a bimodal distribution with transient peaks occurring on days 1 and 7. Mean levels of myeloperoxidase activity in pressure ulcers were significantly higher than at any time in the acute wounds, whereas hyaluronan levels were significantly lower than at any time in the acute wounds. Levels of hyaluronidase activity increased slightly in the postwound period. Hyaluronidase activity in pressure ulcers was significantly elevated compared with the acute wounds. These results suggest a role for increased enzymatic degradation of hyaluronan as a function of inflammation during wound repair. This is the first reported quantitative examination of hyaluronan expression in human acute dermal wounds and in chronic pressure ulcers.

Novel sulfonated hydrogel composite with the ability to inhibit proteases and bacterial growth.

There is a growing interest in the development of wound dressings that possess functionality beyond providing physical protection and an optimal moisture environment for the wound. To this end, a novel dressing material based on a sulfonated triblock polymer has been developed. This versatile polymer possesses an ion-exchange capability that is amenable to binding and controlled release of a variety of therapeutic agents. This sulfonated polymer offers several advantages over existing commercial hydrogels used as wound dressings. These include (1) hydrophilicity that is proportional to sulfonation level, (2) easy preparation of fabric supported dressings (e.g., polyester, cotton, nylon), (3) excellent mechanical integrity of the materials when hydrated, (4) stability to a variety of chemistries, and (5) stability to a variety of sterilization methodologies. In this study, polymer was coated onto a polyester fabric and then modified by ion exchange to prepare the sodium, silver, or doxycycline salts. These sulfonated triblock polymer formulations were then evaluated for their capacity to sequester the neutrophil proteases, elastase, and collagenase-2 (MMP-8). Several of the formulations were found to sequester significant amounts of either elastase or collagenase. These formulations were demonstrated to be tested against a commercially available dressing that is currently marketed for its protease-inhibiting capability. The experimental dressing was statistically superior to the commercial dressing at inhibiting MMP-8 and elastase under the same conditions.

Regulation of hyaluronan synthase-2 expression in human intestinal mesenchymal cells: mechanisms of interleukin-1beta-mediated induction.

Elevated levels of hyaluronan are associated with numerous inflammatory diseases including inflammatory bowel disease. The purpose of this study was to determine whether a cause and effect relationship might exist among proinflammatory cytokines, IL-1beta, TNF-alpha, IFN-gamma, or transforming growth factor-beta (TGF-beta) and hyaluronan expression in human JDMC and, if so, to identify possible mechanisms involved in the induction of hyaluronan expression. TGF-beta, TNF-alpha, and IFN-gamma had little or no effect on hyaluronan production by these cells. Treatment with IL-1beta induced an approximate 30-fold increase in the levels of hyaluronan in the medium of human jejunum-derived mesenchymal cells. Ribonuclease protection analysis revealed that steady-state transcript levels for hyaluronan synthase (HAS)2 were present at very low levels in untreated cells but increased as much as 18-fold in the presence of IL-1beta. HAS3 transcript levels were also increased slightly by exposure of these cells to IL-1beta. Expression of HAS1 transcripts was not detected under any condition in these cells. IL-1beta induction of hyaluronan expression was inhibited in cells transfected with short interfering RNA corresponding to HAS2 transcripts. Inhibitors of the p38 and ERK1/2 mitogen-activated pathways but not JNK/SAPK blocked the IL-1beta-mediated induction of hyaluronan expression and the increase in HAS2 transcript expression. These results suggest that IL-1beta induction of HAS2 expression involves multiple signaling pathways that act in concert, thus leading to an increase in expression of hyaluronan by jejunum-derived mesenchymal cells.

Linoleic acid induces interleukin-8 production by Crohn's human intestinal smooth muscle cells via arachidonic acid metabolites.

Previously we reported that linoleic acid (LA), but not oleic acid, caused a marked increase in the secretion of IL-8 by Crohn's human intestinal smooth muscle (HISM) cells. Antioxidants inhibited this response, implicating a role for oxidative stress and NF-kappaB, a transcription factor for IL-8 that is activated by oxidative stress. In this study, we examined two mechanisms whereby LA, the dietary precursor for arachidonic acid (AA), could increase the production of IL-8 via activation of AA pathways: 1) by generation of reactive oxygen species by the AA-pathway enzymes to activate NF-kappaB or 2) by AA metabolites. Normal and Crohn's HISM cells were exposed to LA, oxidizing solution (Ox), or oxidizing solution enriched with LA (OxLA). Exposure of cells to Ox or OxLA induced oxidative stress as determined by thiobarbituric acid reactive substances. In normal cells, Ox but not LA activated NF-kappaB as determined by transfection experiments and Western blot. In Crohn's cells, NF-kappaB was spontaneously activated and was not further activated by Ox or LA. In contrast, TNF-alpha markedly increased activation of NF-kappaB in both normal and Crohn's cells. These results indicated that LA did not increase IL-8 by activating NF-kappaB, so we evaluated the second mechanism of an effect of AA metabolites. In normal cells, OxLA, but not LA, markedly stimulated IL-8, whereas in Crohn's cells, both OxLA and LA stimulated IL-8. OxLA, also stimulated production of AA metabolites leukotriene B(4) (LTB(4)), PGE(2), and thromboxane B(2) (TXB(2)) by normal and Crohn's cells. To determine whether AA metabolites mediated the IL-8 response, cells were treated with OxLA plus indomethacin (Indo), a cyclooxygenase inhibitor, and nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor. Both Indo and NDGA blocked the IL-8 response to OxLA. To determine more specifically a role for AA metabolites, AA was used. Similar to OxLA, OxAA stimulated production of IL-8 and AA metabolites. Pinane thromboxane, a selective thromboxane synthase inhibitor and receptor blocker, inhibited OxAA stimulation of TXB(2) and IL-8 in a dose-response manner. MK886, a selective 5-lipoxygenase inhibitor, inhibited OxAA stimulation of LTB(4) and IL-8 also in a dose-response manner. Analysis of specific gene products by RT-PCR demonstrated that HISM cells expressed receptors for both thromboxane and LTB(4). We conclude that AA metabolites mediated the IL-8 response to LA in HISM cells. Both cyclooxygenase and lipoxygenase pathways were involved. LA did not increase IL-8 by activating NF-kappaB, but NF-kappaB appeared to be involved, because LA increased IL-8 only in situations where NF-kappaB was activated, either spontaneously in Crohn's cells or by Ox in normal cells. We speculate that AA metabolites increased IL-8 production by enhancing NF-kappaB-dependent transcription of IL-8.

[Amniotic fluid embolism: successful evolution course after uterine arteries embolization]. / Embolie de liquide amniotique: évolution favorable après embolisation thérapeutique des artères utérines.

A 28-year-old woman, G3P3, who was otherwise healthy and had taken no medication and had no known allergy, was admitted to our hospital for delivery after a normal pregnancy. An epidural catheter was inserted for analgesia and labour was induced with oxytocin. Two hours later, she suffered a sudden cardiac arrest. She was immediately treated and, since a normal cardiac rhythm and a blood pressure of 90 mmHg has been obtained 30 minutes later, a 3750 g child was delivered by caesarean section. Soon after delivery, a life-threatening uterine haemorrhage appeared, due to DIC. Evolution was favourable, after bilateral uterine arteries embolization had been performed. The diagnosis of amniotic fluid embolism was established by the clinical course, the absence of local cause and the presence of a large number of amniotic cells in the mother's peripheral blood. Tryptase blood concentration was normal in the mother's blood.

[Hemoperitoneum and pregnancy in a patient with von Willebrand's disease type 3]. / Hémopéritoine et grossesse chez une patiente atteinte de la maladie de von Willebrand de type 3.

A 24-year-old woman with type 3 (characterised by a blood level of von Willebrand factor less than 1%) was admitted to the surgical intensive care unit with an haemorrhagic shock. She was pregnant (Beta HCG = 115 Ul.L-1), the echography of the abdomen, soon after admission, revealed a haemoperitoeum. She underwent abdominal surgery after substitution treatment. The surgeon found an ovarian haemorrhagic cyst. Later the course of pregnancy was normal and she was delivered by caesarean section. We describe the therapeutic strategy of that care.

[Percutaneous tracheostomy]. / Trachéotomie percutanée.

OBJECTIVES: The aim of this study was to evaluate the different techniques of percutaneous tracheostomies, their advantages, drawbacks, complications and to compare them to standard surgical tracheostomies. This study will consider only elective (non emergency) bedside procedures in intensive care units. DATA SOURCES: Extraction from Medline database of english and french articles on percutaneous tracheostomies and searching along with major review articles. STUDY SELECTION: The collected articles were selected according to their qualities regarding to their evidence level. In addition to several important or historic references, the literature of the five past years was studied. DATA EXTRACTION: The articles were reviewed according to their contribution for techniques, perioperative and postoperative complications, recent advances, advantages and drawbacks of all procedures. Publications addressing recent comparisons between surgical and percutaneous tracheostomies were specially studied. DATA SYNTHESIS: Four techniques of bedside percutaneous tracheostomies are available and marketed, in France: Ciaglia's dilation technique (with multiple or unique dilator), Griggs's technique (using a special designed forceps), and Fantoni's technique (Trans Laryngeal Tracheostomy). The most spred but also first described technique is the Ciaglia's (1985). The most recent articles comparing surgical and percutaneous tracheostomies techniques are not able to demonstrate a superiority of one of them in terms of feasibility or safety. In other words, there should be a slight advantage for the percutaneous tracheostomy regarding to the late post-operative complications, as there should be a slight advantage for the surgical techniques regarding to the perioperative complications. The literature analysis point out firstly the learning curve for percutaneous dilational tracheostomy, with a significant decrease of complication incidence with the operator's experience and secondly the continuous endoscopic guidance seems to increase the safety of the percutaneous procedure. CONCLUSION: Since there has been a great deal of percutaneous tracheostomy in the intensive care units, the incidence of tracheostomy have increased in those services. There is a trend to replace the surgical procedure by the percutaneous one. However, according to the potentially jeopardizing complications, percutaneous tracheostomy should be done by an experienced operator with the help of a continuous endoscopic guidance.

[Tracheal gas insufflation associated with mechanical ventilation for CO2 removal]. / Insufflation trachéale de gaz associée à la ventilation mécanique pour l'épuration du CO2.

OBJECTIVE: Tracheal gas insufflation (TGI) either continuously, or at inspiration, or at expiration, is a technique associated with mechanical ventilation aimed to enhance CO2 elimination in favouring washout of anatomical dead space. This article analyses the mechanism of action, the techniques and the effects of TGI in presence of hypercapnia, especially in the fame of ARDS in adults. DATA SOURCES: In addition to some historical or major references, the articles on TGI published over the past five years have been searched in the Medline data base. STUDY SELECTION: Articles with data on TGI associated with mechanical ventilation were selected. DATA EXTRACTION: Data on mechanisms of action, technical and practical aspects of TGI were extracted. DATA SYNTHESIS: CO2 elimination is increased when the TGI catheter tip is close to the carina, when the gas jet is directed towards the latter, by a continuous gas jet, by a high washing gas volume. The effect on oxygenation is minor. The work of breathing is decreased. An increased intracranial pressure is decreased. Circulatory effects are minor. The major risk is dynamic pulmonary over distension. Local complications include dessiccation and lesion of bronchial mucosa by the gas jet. CONCLUSION: In mechanically ventilated patients, additional TGI is a valuable technique for decreasing anatomical dead space. TGI decreases hypercapnia during mechanical ventilation with limited tidal volumes in permissive hypercapnia. Further clinical studies with large series of patients are required to assess the benefits and the effect of TGI on outcome.

Calibration of seven ICU ventilators for mechanical ventilation with helium-oxygen mixtures.

The study evaluated seven intensive care unit (ICU) ventilators (Veolar FT, Galileo, Evita 2, Evita 4, Servo 900C, Servo 300, Nellcor Puritan Bennett 7200 Series) with helium-oxygen (HeO2), using a lung model, to develop correction factors for the safe use of HeO2. A 70:28 helium-O2 mixture (heliox) replaced air and combined with O2 (HeO2). Theoretical impact of HeO2 on inspiratory valves and gas mixing was computed. True fraction of inspired oxygen (FIO2del) was compared with fraction of inspired oxygen (FIO2) set on the ventilator (FIO2set). True tidal volume (VTdel) was compared with VT set on the ventilator (VTset) in volume control and with control VTdel at FIO2 1.0 in pressure control. FIO2del minimally exceeded FIO2set ( FIO2set by 125%). In volume control, with the Veolar FT, Galileo, Evita 2, and Servo 900C, VTdel > VTset, with the 7200 Series VTdel < VTset (linear relationship, magnitude of discrepancy inversely related to FIO2set). With the Evita 4, VTdel > VTset (nonlinear relationship), whereas with the Servo 300 VTdel = VTset. In pressure control, VTdel was identical to control measurements, except with the 7200 Series (ventilator malfunction). Correction factors were developed that can be applied to most ventilators.

Ability of chronic wound fluids to degrade peptide growth factors is associated with increased levels of elastase activity and diminished levels of proteinase inhibitors.

The stability of peptide growth factors exposed to fluids from healing surgical wounds and from nonhealing chronic wounds was examined in vitro. (125)I-Labeled transforming growth factor-beta1 or platelet-derived growth factor-BB was incubated with fluids from healing surgical wounds and fluids from venous stasis or pressure ulcers. Fluids from healing surgical wounds had no appreciable effect on the level of (125)I corresponding to intact growth factor. In contrast, incubation with fluids from several venous stasis or pressure ulcers resulted in significant degradation of these growth factors. Degradation was blocked by broad-spectrum serine proteinase inhibitors and by specific inhibitors of neutrophil elastase. Levels of elastase activity in wound fluids correlated with the ability to degrade peptide growth factors. Further comparisons showed qualitative and quantitative differences in the endogenous proteinase inhibitors, alpha2-macroglobulin and alpha1-antiproteinase. These results could explain, in part, the variable growth factor levels which have been found in chronic wounds. More importantly, the ability of some chronic nonhealing wounds to rapidly degrade exogenously added growth factors has important implications with regard to past and future clinical attempts to use peptide growth factors to treat these types of problem wounds.

[Surgery for epidermolysis bullosa in children: value of the association of inhalation anesthesia and locoregional anesthesia]. / Chirurgie de l'épidermolyse bulleuse grave chez l'enfant: intérêt de l'association anesthésie générale par inhalation-anesthésie locorégionale.

Due to the cutaneous and mucosal fragility associated with epidermolysis bullosa, this disease is a source of various practical problems for the anaesthesiologist concerning the surgical posture, the monitoring of vital functions, the airways control and the vascular access, as all these procedures may worsen, sometimes dramatically, the lesions in these young patients, still in a precarious health state. Basing on published studies and their own experience, the authors have used in these patients a combined locoregional and general anaesthesia. The latter was obtained with isoflurane, administered in the non intubated and spontaneously breathing patient through a closed surgical isolation container (Vi-Drape), including the patient's head and ventilated with a ventilator generating a PEEP for long procedures. The results obtained during 9 procedures in 3 children are reported and discussed. For several shorter procedures (for example wound dressing), intramuscular ketamine was used.