Lipolytic Esterases in Staphylococci

Staphylococci split a wide range of lipid substrates by production of an enzyme complex with two main components (i) a lipase acting optimally on fat-soluble glycerides, and (ii) an esterase acting optimally on water-soluble esters. The action is dependent upon carbon chain length, interfacial dispersion, solubility, and pH of substrate and end products. The esterase is less susceptible to organophosphorus inhibitors than mammalian esterases. There is no apparent correlation between lipolysis and markers of pathogenicity such as production of coagulase and toxin, but the possession of a flexible lipolytic mechanism might account for the persistence of staphylococci in the fatty secretions of mammalian skin.     

Effects of interleukin-8 on granulation tissue maturation

The inflammatory alpha-chemokine, interleukin-8 (IL-8), affects the function and recruitment of various inflammatory cells, fibroblasts, and keratinocytes. Gap junctions are anatomical channels that facilitate the direct passage of small molecules between cells. The hypothesis is that IL-8 enhances gap junctional intercellular communication (GJIC) between fibroblasts in granulation tissue, which increases the rate of granulation tissue maturation. In vitro, human dermal fibroblasts were incubated with IL-8 prior to scrape loading, a technique that quantifies GJIC. Polyvinyl alcohol (PVA) sponges were implanted within subcutaneous pockets in rats and received local injections of either IL-8 or saline and were harvested on day 11. In vitro, IL-8 treated fibroblasts demonstrated an increase in GJIC by scrape loading compared to saline treated controls. In vivo, IL-8 treated PVA sponges demonstrated a decrease in cell density and an increase in vascularization compared to saline controls by H&E staining. Polarized light viewed Sirius red-stained specimens demonstrated greater collagen birefringence intensity, indicating thicker, more-mature collagen fibers. IL-8 increases GJIC in cultured fibroblasts and induces a more rapid maturation of granulation tissue.     

Optimization of alpha-acylaminoketone ecdysone agonists for control of gene expression

Fifteen new alpha-acylaminoketones were prepared by four different routes in an initial effort to optimize the potency of these compounds as ecdysone agonists. The compounds were assayed in mammalian cells expressing the ecdysone receptors from Bombyx mori (BmEcR) and Choristoneura fumiferana (CfEcR) for their ability to cause expression of a reporter gene downstream of an ecdysone response element. A new alpha-acylaminoketone was identified which had activity equal to that of the standard dibenzoylhydrazine ecdysone agonist GS()-E in the assay based on CfEcR.     

The natural history of the growth of the hand: I. Hand area as a percentage of body surface area

The use of a patient's own hand as a tool to estimate the area of burn injury is well documented. The area of the palmar surface of one hand has been estimated to be 1 percent of the body surface area. The area of the palmar surface of the hand was measured to test the accuracy of this estimate and then compared with the body surface area as calculated by formulas in common use. This study also sought to determine the natural history of the growth of the hand to permit development of a readily available, bedside means of estimating hand area and body surface area. Bilateral hand tracings were obtained from 800 volunteers ranging in age from 2 to 89 years. The area of each tracing was determined using an integrating planimeter. The height and weight of each individual were measured, and his/her body surface area was calculated. The palmar hand's percentage of body surface area was determined by calculating the quotient for hand area divided by body surface area. Additionally, the width of the hand was measured from the ulnar aspect at the palmar digital crease of the small finger to the point where the thumb rested against the base of the index finger. The length of the hand was measured from the middle of the interstylon to the tip of the middle finger. These two figures were multiplied together to obtain a product which approximated the area of the hand. Based on the most commonly used DuBois formula for calculating body surface area, the area of palmar surface of the hand corresponds to 0.78 +/- 0.08 percent of the body surface area in adults. The percentage varies somewhat with age and reaches a maximum of 0.87 +/- 0.06 percent in young children. Multiplying the length of the hand by its width overestimates the area of the hand as determined by planimetry by only 2 percent. A patient's own hand may be used as a complementary, readily available template for estimation of burn area or other areas of disease or injury. In adults, the area of tracing of the outline of the hand is 0.78 percent of the body surface area, whereas in children, this number tends to be slightly higher. In the emergency room or on the wards, a simple product of length multiplied by width of the hand will closely approximate the area as determined by planimetry. This method allows a more accurate determination of the area of the palmar surface of the hand than the 1 percent estimate, which may lead to an overestimation of the size of a burn wound in adults.     

Rat mast cells communicate with fibroblasts via gap junction intercellular communications

Usually mast cells (MCs) modulate other cellular activities through the release of their cytoplasmic granules. Recently, gap junctional intercellular communication (GJIC) between an established human MC cell line (HMC-1) co-cultured with human dermal fibroblasts in fibroblast populated collagen lattices (FPCLs), enhanced the rate and degree of FPCL contraction. However, HMC-1 cells were unable to generate GJIC with human neonatal fibroblasts in monolayer culture. Here freshly isolated rat peritoneal MCs are co-cultured with fibroblasts in collagen lattices and in monolayer culture in vitro and introduced into rat polyvinyl alcohol (PVA) sponge implants in vivo. Co-cultured MC-FPCL contracted faster and to a greater degree. Loading Calcein AM green fluorescent dye into red fluorescent Dil tagged MC generates MC-paratroopers. When MC-paratroopers form GJIC with fibroblasts, some green dye is passed into the fibroblast, while the MC-paratrooper retains both its red and green fluorescence. MC-paratroopers passed green fluorescent dye into both human and rat dermal fibroblasts in monolayer culture. In rats 7-day-old subcutaneous PVA sponge implants, which received an injection of MC-paratroopers, exhibited auto-fluorescent green fibroblasts, when harvested 24 h later. MC-paratroopers pretreated with a long-acting GJIC inhibitor prior to their introduction into PVA sponge implants, failed to pass dye into fibroblasts. It is proposed that GJIC between granulation tissue fibroblasts and MCs can modulate some aspects of wound repair and fibrosis.     

Salmonella must be viable in order to attach to the surface of prepared vegetable tissues

Aims: The aims of the current study were to explore the site of bacterial attachment to vegetable tissues and to investigate the hypothesis that Salmonella must be living in order to attach to this site(s). Methods and Results: Scanning electron micrographs of intact potato cells showed that Salm. serotype Typhimurium attached to cell-wall junctions; suggesting a high-level of site selectivity. Inactivation of Salm. Typhimurium using heat, ethanol, formalin or Kanamycin resulted in cells that could be no longer attached to these sites. Attachment of a Gfp⁺ strain of Salm. Typhimurium to cell-wall material (CWM) was examined via flow cytometric analysis. Only live Salm. Typhimurium attached to the CWM. Conclusions: Salmonella serotype Typhimurium must be metabolically active to ensure attachment to vegetable tissues. Attachment preferentially occurs at the plant cell-wall junction and the cell-wall components found here, including pectate, may provide a receptor site for bacterial attachment. Significance and Impact of the Study: Further studies into individual plant cell-wall components may yield the specific bacterial receptor site in vegetable tissues. This information could in turn lead to the development of more targeted and effective decontamination protocols that block this site of attachment.     

Pulp nonfiction: microscopic anatomy of the digital pulp space

The volar pad of the fingertip provides a very stable yet sensitive surface that gives the hand the ability to pinch and grasp. The focus of this study was to advance understanding of the anatomical features of the digital pulp space. The unusual features of the fingertip pulp space include prominent collagen fiber cords and a branching continuous fine vasculature. Prominent collagen fiber cords radiating out from beneath the epidermal basement membrane are like the cords of a parachute, which directly attach to the periosteum of the distal phalanx. Those collagen fiber cords are responsible for the firm attachment of the fingertip to the distal phalanx. There is a fine patent vasculature within the pulp space. Also contained in the capsule are numerous lobules of fat, which contribute to some elasticity of the fingertip. Principles of treatment for injuries or infections of the digital pulp should attempt to preserve this anatomical construct so that the firmness and vascular supply of the fingertip are maintained and not disrupted.