Case Report: Endemic Amebiasis in Australia: Implications for Residents, Travelers, and Clinicians.

Entamoeba histolytica is considered endemic in Australia; however, cases are rare, occurring almost exclusively in high-risk individuals. We describe a series of locally acquired, complicated cases in low-risk individuals from Far North Queensland in whom the diagnosis was delayed. Amebiasis may pose a greater local threat than is currently recognized.

Giant congenital melanocytic nevi and malignant transformation: a case for early radical intervention.

The purpose of this paper is to highlight the risk of early malignant transformation in infants with giant congenital melanocytic nevi (GN) and demonstrate the potential for earlier intervention with aggressive surgery. We describe the case of a child born with a GN who developed a metastatic melanoma early in life, despite early commencement of resection of the nevus. This is contrasted against a second case of a child in which a more radical management was conducted. Despite early commencement of serial resection of the GN, the first child in this series died of metastatic melanoma prior to complete excision of the nevus. With the second child, radical excision combined with the use of Integra™ and negative pressure wound therapy allowed total removal of the GN within the first 6 months of life.

Cyanoacrylate glue as an alternative mounting medium for resin-embedded semithin sections.

Commercially available generic Superglue (cyanoacrylate glue) can be used as an alternative mounting medium for stained resin-embedded semithin sections. It is colourless and contains a volatile, quick-setting solvent that produces permanent mounts of semithin sections for immediate inspection under the light microscope. Here, we compare the use of cyanoacrylate glue for mounting semithin sections with classical dibutyl phthalate xylene (DPX) in terms of practical usefulness, effectiveness and the quality of the final microscopic image.

Microscopic inflammatory foci in burn scars: data from a porcine burn model.

BACKGROUND: Hypertrophic scars in burn victims usually occur after delayed wound healing and the active phase of scar formation can persist substantially even after wound closure. Currently, the pathophysiology of the hypertrophic scar is not completely understood. This study investigated the inflammatory response in scar tissue at week 6 post-burn injury. METHODS: A porcine deep dermal partial thickness burn model was used. At week 6 post-burn, a total of 528 scar biopsies from 72 burn scars (7-8 biopsies from each scar) and 174 normal skin biopsies from 18 pigs were collected and examined histologically. RESULTS: Microscopic inflammatory foci were identified in 17% (89/528) of scar biopsies. These microscopic inflammatory foci do not contain any irritant materials, are composed largely of polymorphonuclear cells with other inflammatory cells including multinucleate giant cells and show acute on chronic inflammatory response that has not been described previously in burn scars. Importantly, they are present in a significantly lower number in burns surgically debrided than in burns which have not been debrided. CONCLUSIONS: This study identifies microscopic inflammatory foci in the porcine scar tissue layer and recommends thorough cleaning/debriding of burned necrotic tissue in order to minimize the formation of these inflammatory foci in scar tissue.

Silver deposits in cutaneous burn scar tissue is a common phenomenon following application of a silver dressing.

BACKGROUND: Silver dressings have been widely and successfully used to prevent cutaneous wounds, including burns, chronic ulcers, dermatitis and other cutaneous conditions, from infection. However, in a few cases, skin discolouration or argyria-like appearances have been reported. This study investigated the level of silver in scar tissue post-burn injury following application of Acticoat, a silver dressing. METHODS: A porcine deep dermal partial thickness burn model was used. Burn wounds were treated with this silver dressing until completion of re-epithelialization, and silver levels were measured in a total of 160 scars and normal tissues. RESULTS: The mean level of silver in scar tissue covered with silver dressings was 136 microg/g, while the silver level in normal skin was less than 0.747 microg/g. A number of wounds had a slate-grey appearance, and dissection of the scars revealed brown-black pigment mostly in the middle and deep dermis within the scar. The level of silver and the severity of the slate-grey discolouration were correlated with the length of time of the silver dressing application. CONCLUSIONS: These results show that silver deposition in cutaneous scar tissue is a common phenomenon, and higher levels of silver deposits and severe skin discolouration are correlated with an increase in the duration of this silver dressing application.

A randomised controlled trial of amniotic membrane in the treatment of a standardised burn injury in the merino lamb.

Burn injury is associated with disabling scar formation which impacts on many aspects of the patient's life. Previously we have shown that the fetus heals a deep dermal burn in a scarless fashion. Amniotic membrane (AM) is the outermost fetal tisue and has beeen used as a dressing in thermal injuries, though there is little data to support this use. To assess the efficacy of AM in scar minimisation after deep dermal burn wound, we conducted a randomised controlled study in the 1-month lamb. Lambs were delivered by caesarian section and the amniotic membranes stored after which lambs were returned to their mothers post-operatively. At 1 month, a standardised deep dermal burn was created under general anaesthesia on both flanks of the lamb. One flank was covered with unmatched AM, the other with paraffin gauze. Animals were sequentially euthanased from Day 3-60 after injury and tissue analysed for histopathology and immunohistochemically for alpha-smooth muscle actin (alphaSMA) content. AM resulted in reduced scar tissue as assessed histopathologically and reduced alphaSMA content. This study provides the first laboratory evidence that AM may reduce scar formation after burn injury.

Generation and characterization of EphA1 receptor tyrosine kinase reporter knockout mice.

Eph receptor tyrosine kinases (RTKs) are a highly conserved family of signaling proteins with functions in cellular migration, adhesion, apoptosis, and proliferation during both adult and embryonic life. Here, we describe a knock-in mouse in which EphA1 expression is disrupted via the insertion of an internal ribosome entry site (IRES)-human placental alkaline phosphatase (ALPP) reporter cassette into exon II of the EphA1 gene. This was shown to successfully knockout expression of endogenous EphA1 and enforce expression of the ALPP reporter by the EphA1 promoter. Staining for the ALPP reporter protein demonstrated an epithelially restricted expression pattern in mouse tissues. In EphA1 null mice, two separate phenotypes were identified: abnormal tail development manifesting as a kinky tail was found in approximately 80% of homozygous adults. A second, distinct abnormality present in approximately 18% of females was characterized by imperforate uterovaginal development with hydrometrocolpos and caused by a resistance of cells to apoptosis during reproductive tract canalization. These results indicate a possible role for EphA1 in tissue patterning and hormone-induced apoptotic processes.

Surveillance culture utility and safety using low-volume blind bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia.

BACKGROUND AND OBJECTIVES: Surveillance cultures may improve the prediction of ventilator-associated pneumonia (VAP) and empirical antibiotic selection. This study examined the utility and patient safety of blind, non-protected, low-volume mini-bronchial lavage (BM-BAL) surveillance cultures in predicting VAP. METHODOLOGY: A prospective, cohort study was performed in a large general intensive care unit. BM-BALs were collected within 12 h of admission then thrice weekly. Each BM-BAL was screened by Gram staining for intracellular organisms and then quantitatively cultured. VAP was diagnosed using the Clinical Pulmonary Infection Score. The concordance for isolates from the BM-BAL was assessed against concurrently collected endotracheal aspirates (EA). RESULTS: Four hundred and twelve patients requiring a minimum of 48 h of mechanical ventilation were enrolled. Fifty patients developed 58 episodes of VAP. Concordant pathogens were found in 85% of BM-BAL specimens collected 2 days prior to VAP onset. Their antibiograms were stable over the preceding 4 days. The isolation of pathogens with colony counts >or=10(4) cfu/mL from BM-BAL performed 2 days prior to the clinical onset of VAP had a sensitivity of 84%, specificity of 50%, positive predictive value of 31% and a negative predictive value of 93% for predicting the development of VAP. BM-BAL WCC, quantification of bacterial growth and the percentage of intracellular organisms were not helpful in predicting VAP diagnosis. CONCLUSIONS: BM-BAL surveillance cultures are well tolerated and useful in predicting the pathogens and their antibiograms causing VAP. Diagnostic specimen collection at the time of VAP onset is still required as surveillance cultures may be negative even one day prior to VAP onset.

Conservative surgical debridement as a burn treatment: supporting evidence from a porcine burn model.

In thermal deep-dermal burns, surgical debridement is normally used in conjunction with skin grafting or skin substitutes and debridement alone as a burn treatment is not usually practiced. The current study addresses whether or not debridement alone would enhance burn wound healing on small deep-dermal-partial thickness burns. This was a prospective and blinded experimental trial using a porcine deep-dermal-partial thickness burn model. Four burns, approximately 50 cm(2) in size, were created on each of eight pigs. Two burns from each pig were immediately surgically debrided and the other two were not debrided as the internal control. Hydrate gel together with paraffin gauze were used to cover the burns for four pigs and silver dressings for the other four. Clinical assessment of wound healing was conducted over a 6-week period. Skin samples were collected at the end of the experiment and histopathological evaluation was performed. The results show thinner scar formation and lower scar height in the debrided compared with nondebrided wounds in the hydrate gel/paraffin gauze groups. There were no statistically significant differences in wound healing assessment between the debrided and nondebrided wounds dressed with silver dressings. This study provides supporting evidence that immediate debridement with an appropriate dressing and without skin grafting may promote wound healing, suggesting its potential benefit for clinical patients.

The optimal temperature of first aid treatment for partial thickness burn injuries.

Using our porcine model of deep dermal partial thickness burn injury, various cooling techniques (15 degrees C running water, 2 degrees C running water, ice) of first aid were applied for 20 minutes compared with a control (ambient temperature). The subdermal temperatures were monitored during the treatment and wounds observed and photographed weekly for 6 weeks, observing reepithelialization, wound surface area and cosmetic appearance. Tissue histology and scar tensile strength were examined 6 weeks after burn. The 2 degrees C and ice treatments decreased the subdermal temperature the fastest and lowest, however, generally the 15 and 2 degrees C treated wounds had better outcomes in terms of reepithelialization, scar histology, and scar appearance. These findings provide evidence to support the current first aid guidelines of cold tap water (approximately 15 degrees C) for 20 minutes as being beneficial in helping to heal the burn wound. Colder water at 2 degrees C is also beneficial. Ice should not be used.

A porcine deep dermal partial thickness burn model with hypertrophic scarring.

We developed a reproducible model of deep dermal partial thickness burn injury in juvenile Large White pigs. The contact burn is created using water at 92 degrees C for 15s in a bottle with the bottom replaced with plastic wrap. The depth of injury was determined by a histopathologist who examined tissue sections 2 and 6 days after injury in a blinded manner. Upon creation, the circular wound area developed white eschar and a hyperaemic zone around the wound border. Animals were kept for 6 weeks or 99 days to examine the wound healing process. The wounds took between 3 and 5 weeks for complete re-epithelialisation. Most wounds developed contracted, purple, hypertrophic scars. On measurement, the thickness of the burned skin was approximately 1.8 times that of the control skin at week 6 and approximately 2.2 times thicker than control skin at 99 days after injury. We have developed various methods to assess healing wounds, including digital photographic analysis, depth of organising granulation tissue, immunohistochemistry, electron microscopy and tensiometry. Immunohistochemistry and electron microscopy showed that our porcine hypertrophic scar appears similar to human hypertrophic scarring. The development of this model allows us to test and compare different treatments on burn wounds.

Deep dermal burn injury results in scarless wound healing in the ovine fetus.

Early to mid-term fetuses heal cutaneous incisional wounds without scars; however, fetal response to burn injury has not been ascertained. We present a fetal model of thermal injury and subsequent analysis of fetal and lamb response to burn injury. A reproducible deep dermal burn injury was created in the fetus by application of water at 66 degrees C for 7 seconds, and at 82 degrees C for 10 seconds to the lamb. Macroscopically, the area of fetal scald was undetectable from day 7 post injury, while all lamb scalds were readily identified and eventually healed with scarring. Using a five-point histopathology scoring system for alteration in tissue morphology, differences were detected between control and scalded skin at all stages in lamb postburn, but no difference was detected in the fetal model after day 7. There were also large differences in content of alpha-smooth muscle actin and transforming growth factor-beta1 between control and scalded lamb and these differences were statistically significant at day 14 (P < 0.01). This novel model of fetal and lamb response to deep dermal injury indicates that the fetus heals a deep burn injury in a scarless fashion. Further elucidation of this specific fetal process of burn injury repair may lead to improved outcome for patients with burn injury.