Comparison of the open technique with a new wound dressing,H2460, in the healing of an acute wound after laser skin resurfacing

Background: Applying various dressings or leaving the treated area open are two techniques in use after laser skin resurfacing (LSR). Objective: This study was conducted to compare healing of an acute wound using a new hydrocolloid dressing, H2460, with the open technique. Methods: Immediately after LSR, one side was covered with the new hydrocolloid dressing H2460 and the other side was left open. Participants were instructed to clean the open side four times a day and replace the H2460 dressing if it was dislodged. Results: In the volunteers' and investigator's evaluations, the new dressing H2460 generally outperformed the ‘open’ technique. At the 1‐month follow‐up, eight of 10 volunteers reported that the H2460 side resulted in better healing; two of 10 volunteers felt there was no difference between the two sides for final outcome and none believed that the open side had better healing. Overall, the H2460 side healed better in the majority of participants as graded by the blinded observer (60%) and participant themselves (80%). Conclusion: The new hydrocolloid dressing H2460 is a better and suitable alternative to the open technique to manage an acute wound after LSR.     

Comparison of two wound dressings after laser skin resurfacing.

BACKGROUND: It has been reported that the final outcome of laser resurfacing still depends to a large degree on the efficiency of the post laser resurfacing wound care in promoting wound healing and preventing early and late complications. OBJECTIVE: The objective of this study was to evaluate and compare a new hydrocolloid dressing, H2460, with Flexzan(TM) for healing of an acute wound after laser skin resurfacing (LSR). METHODS: Ten volunteers received LSR of the peri-orbital area with an erbium:YAG laser. Identical parameters were used on both sides: 2 J, 5 mm spot, 8 Hz, 300 micros pulse, two passes on the upper eyelids, four passes on the lower eyelids and six passes on the crow's feet area. Soon after the LSR, one side was covered with Flexzan dressing and the other side was covered with a new hydrocolloid dressing -- H2460. The side of the dressing was randomized by alternating both dressings. All volunteers were evaluated and digitally photographed every day for a week and at 1 month after LSR. The degree of erythema, swelling, bleeding, oozing, crusting, pigmentary changes, scarring, discomfort, itching, burning, ease of application of dressings, initial adhesion, overall adhesion, leakage of fluid, maceration of surrounding skin, ease of removal and adhesive residue upon removal were documented. RESULTS: In all volunteer and investigator's evaluations, the new dressing, H2460, achieved far better results than Flexzan in each category. After a 1-week follow-up all volunteers and the investigator evaluated the H2460 side as: healed better, simple to use, and caused less discomfort in 10 out of 10 volunteers. The blinded observer's assessment showed that the Flexzan side healed better in one volunteer. CONCLUSION: The new dressing, H2460, is a better and suitable alternative to Flexzan as a post LSR dressing.     

Injury and nucleotides induce phosphorylation of epidermal growth factor receptor: MMP and HB-EGF dependent pathway

The early events that occur rapidly after injury trigger signal cascades that are essential for proper wound closure of corneal epithelial cells. We hypothesize that injury releases ATP, which stimulates purinergic receptors and elicits the phosphorylation of epidermal growth factor receptor (EGFR) tyrosine residues and subsequent cell migration by a MMP and HB-EGF dependent pathway. We demonstrated that the inhibition of purinergic receptors with the antagonist, Reactive Blue 2, abrogated the phosphorylation of EGFR and ERK. Pre-incubation of cells with the EGFR kinase inhibitor, AG1478, and subsequent stimulation by injury or ATP resulted in a decrease in phosphorylation of EGFR and migration. Furthermore, downregulation of EGFR by siRNA, inhibited the EGF-induced intracellular Ca(2+) wave. However, the response to injury and ATP was retained indicating the presence of two signaling pathways. Inhibition with either CRM197 or TIMP-3 decreased injury and nucleotide-induced phosphorylation of both EGFR and ERK. Incubation in the presence of a functional blocking antibody to HB-EGF also resulted in a decrease in the phosphorylation of EGFR. In addition, cell migration was inhibited by CRM197 and rescued when cells were incubated with HB-EGF. We showed that injury-induced phosphorylation of specific tyrosine residues and found that a similar pattern of phosphorylation was induced by trinucleotides. These studies indicate that injury-induced purinergic receptor activation leads to phosphorylation of EGFR, ERK and migration.     

Detection of a novel Tet M determinant in tetracycline-resistant Neisseria gonorrhoeae from Uruguay, 1996-1999

BACKGROUND: Determination of the diversity within the tet(M) sequence from N gonorrhoeae is a useful epidemiologic tool for monitoring the movement or importation of strains within a geographic region. Only two distinct tet(M) genes in clinical gonococcal isolates have been described up to now: the Dutch and the American types. GOAL: The study involved surveillance of the tet(M) gene types in high-level-tetracycline-resistant gonococcal isolates from Uruguay during the period 1996 to 1999. STUDY DESIGN: Among 181 gonococcal isolates, those showing MICs >/=16 microg/ml to tetracycline were analyzed for detection and characterization of the tet(M) gene by a polymerase chain reaction (PCR) and further HpaII restriction fragment polymorphism methods, respectively. The plasmid content and antibiogram were determined. RESULTS: Twenty-two of 181 isolates (12%) exhibited high levels of resistance to tetracycline (MICs >/=16 microg/ml) and harbored a putative 25.2-Mda plasmid that contained the tet(M) gene. A high percentage of isolates (95%; 21/22) presented the Dutch type tet(M) gene. One isolate from 1999 revealed a new restriction pattern. Such a pattern had been previously noted in 1991. This new restriction pattern has not been described previously as occurring in isolates of N gonorrhoeae. The tet(M) amplimer sequence showed 100% identity with a previously described tet(M)-carrying plasmid from N meningitidis. CONCLUSION: A new HpaII restriction pattern of the tet(M) gene is present in low frequency. The tet(M) sequence was different from the gonococcal tet(M) sequences already known and not typable with the use of a differential PCR assay. Accordingly, with the genetic diversity already present within the tet(M) sequence of N gonorrhoeae isolates, we should be aware of the sensitivity of the PCR assays in use for tetracycline-resistant N gonorrhoeae detection.     

Changes with ageing in several leukocyte functions of male and female rats

The impairment of the immune system with aging, or immunosenescence, appears to contribute to the increased morbidity and mortality of aged subjects. T cell functions and Natural Killer activity seem to be the immune responses most affected by ageing. Since the immune system works more efficiently in females than in males, we have studied the changes of several immune functions with age in rats of both sexes. In addition, we have investigated if ovariectomy, a model of menopause in rats, produces a loss of this gender-related advantage. In the present work, the changes with age (2, 6, 12, 14, 18, 22 and 24 months old) in lymphocyte chemotaxis, T lymphoproliferative response to the mitogen ConA, IL-2 release and Natural Killer activity of cells from axillary nodes and spleen of male and female rats as well as of females ovariectomized at 12 months of age have been studied. An age-related decrease was found in all investigated functions, with a slightly different evolution depending on the immune organ and gender considered. In general, the data obtained show that a certain degree of immunosenescence takes place with age in rats, with males being less immunocompetent than intact age-matched females, but showing an immune response similar to that of ovariectomized animals.     

Caspase-6 activity predicts lower episodic memory ability in aged individuals

Caspase-6 (Casp6), a cysteinyl protease that induces axonal degeneration, is activated early in Alzheimer Disease (AD) brains. To determine whether Casp6 activation is responsible for early cognitive impairment, we investigated the abundance of Casp6 activity, paired helical filament–1 (PHF-1) phosphorylated Tau and amyloid beta peptide (Aβ) pathology by immunohistochemistry in the hippocampal formation of aged non–cognitively impaired (NCI) individuals. Casp6 activity was restricted to the entorhinal cortex (ERC) and CA1 regions of the hippocampus. Pathology scores were then correlated with cognitive scores obtained within 1 year of death. Regression analyses revealed that ERC and CA1 Casp6 activity were the main contributor to lower episodic memory performance, whereas ERC PHF-1 pathology predicted lower semantic and working memory performance. Aβ did not correlate with any of the cognitive tests. Because Casp6 activity and PHF-1 pathology are intimately associated with AD pathology and memory decline is an early event in AD, we conclude that Casp6 activity and PHF-1 immunoreactivity in ERC identifies aged individuals at risk for developing AD.     

Blocking of integrins inhibits HIV‐1 infection of human cervical mucosa immune cells with free and complement‐opsonized virions

The initial interaction between HIV‐1 and the host occurs at the mucosa during sexual intercourse. In cervical mucosa, HIV‐1 exists both as free and opsonized virions and this might influence initial infection. We used cervical explants to study HIV‐1 transmission, the effects of opsonization on infectivity, and how infection can be prevented. Complement opsonization enhanced HIV‐1 infection of dendritic cells (DCs) compared with that by free HIV‐1, but this increased infection was not observed with CD4⁺ T cells. Blockage of the α4‐, β7‐, and β1‐integrins significantly inhibited HIV‐1 infection of both DCs and CD4⁺ T cells. We found a greater impairment of HIV‐1 infection in DCs for complement‐opsonized virions compared with that of free virions when αM/β2‐ and α4‐integrins were blocked. Blocking the C‐type lectin receptor macrophage mannose receptor (MMR) inhibited infection of emigrating DCs but had no effect on CD4⁺ T‐cell infection. We show that blocking of integrins decreases the HIV‐1 infection of both mucosal DCs and CD4⁺ T cells emigrating from the cervical tissues. These findings may provide the basis of novel microbicidal strategies that may help limit or prevent initial infection of the cervical mucosa, thereby reducing or averting systemic HIV‐1 infection.