Long-term scarring outcomes and safety of patients treated with NovoSorbⓇ Biodegradable Temporizing Matrix (BTM): An observational cohort study.

Background/Aim: NovoSorbⓇ Biodegradable Temporizing Matrix (BTM) is a relatively novel, biodegradable polyurethane-based dermal regeneration template. The aim of this study was to evaluate the long-term scarring outcomes and safety of BTM in patients who underwent dermal reconstruction involving ≥5% of the total body surface area. Methods: This was a postmarket, multicenter, observational cohort study involving evaluation of long-term outcomes in patients treated with BTM. A total of 55 patients (35 from Royal Adelaide Hospital, South Australia, and 20 from Victoria Adult Burns Service, The Alfred, Victoria) who underwent dermal repair with BTM between 2011 and 2017 were screened for inclusion in this study. All patients had BTM implanted for ≥18 months. Results: Fifteen eligible patients with a mean (SD) age of 49.1 (14.3) years completed study assessments. These patients had a total of 39 areas treated with BTM. Using the Patient and Observer Scar Assessment Scale, scar quality was reported to be good by both observers and patients, with a mean (SD) observer score across all lesions of 3.6 (1.2) and mean (SD) overall opinion of 3.8 (1.2) as well as a mean (SD) patient score of 3.5 (1.2) and overall opinion of 5.0 (2.2). No adverse events or adverse device effects were reported or identified. Conclusion: The long-term scar quality is comparable to published studies. BTM is safe in the long term with no additional risks or adverse consequences being identified.

Immersion freezing of supermicron mineral dust particles: freezing results, testing different schemes for describing ice nucleation, and ice nucleation active site densities.

Ice nucleation on mineral dust particles is known to be an important process in the atmosphere. To accurately implement ice nucleation on mineral dust particles in atmospheric simulations, a suitable theory or scheme is desirable to describe laboratory freezing data in atmospheric models. In the following, we investigated ice nucleation by supermicron mineral dust particles [kaolinite and Arizona Test Dust (ATD)] in the immersion mode. The median freezing temperature for ATD was measured to be approximately -30 °C compared with approximately -36 °C for kaolinite. The freezing results were then used to test four different schemes previously used to describe ice nucleation in atmospheric models. In terms of ability to fit the data (quantified by calculating the reduced chi-squared values), the following order was found for ATD (from best to worst): active site, pdf-α, deterministic, single-α. For kaolinite, the following order was found (from best to worst): active site, deterministic, pdf-α, single-α. The variation in the predicted median freezing temperature per decade change in the cooling rate for each of the schemes was also compared with experimental results from other studies. The deterministic model predicts the median freezing temperature to be independent of cooling rate, while experimental results show a weak dependence on cooling rate. The single-α, pdf-α, and active site schemes all agree with the experimental results within roughly a factor of 2. On the basis of our results and previous results where different schemes were tested, the active site scheme is recommended for describing the freezing of ATD and kaolinite particles. We also used our ice nucleation results to determine the ice nucleation active site (INAS) density for the supermicron dust particles tested. Using the data, we show that the INAS densities of supermicron kaolinite and ATD particles studied here are smaller than the INAS densities of submicron kaolinite and ATD particles previously reported in the literature.

Prevention of gastrointestinal bleeding due to stress ulceration: a review of current literature.

Our objective was to audit our current stress ulcer prophylaxis protocol (routine prescription of ranitidine and early enteral feeding) by identifying whether routine prescription of histamine-2 receptor antagonists or proton pump inhibitors as prophylaxis against stress-related mucosal disease and subsequent upper gastrointestinal bleeding is supported in the literature. We also aimed to ascertain what literature evidence supports the role of early enteral feeding as an adjunctive prophylactic therapy, as well as to search for burn-patient specific evidence, since burn patients are at high risk for developing this condition, with the aim of changing our practice. PubMed and Cochrane databases were searched for relevant articles, yielding seven randomised controlled trials comparing histamine-2 receptor antagonists and proton pump inhibitors in the prevention of upper gastrointestinal bleeding associated with stress-related mucosal disease and three separate meta-analyses. Despite level 1 clinical evidence, no significant difference in efficacy between histamine-2 receptor antagonists and proton pump inhibitor treatment groups was demonstrated. No significant difference was demonstrated in the incidence of nosocomial pneumonia between the two drugs given in this indication. However, enteral feeding was found to be safe and effective in preventing clinically significant upper gastrointestinal bleeding. Patients able to tolerate feeds demonstrated no additional benefit with concomitant pharmacological prophylactic therapy. Since all burn patients at the Royal Adelaide Hospital are fed from very early in their admission, the literature suggests that we, like our intensive care unit colleagues, should abolish our reliance on pharmacological prophylaxis, the routine prescription of which is not supported by the evidence.

The heat shock proteins and plastic surgery.

Heat shock proteins are diverse and essential components of cell physiology. Their expression is elevated in the cell undergoing stress, where they protect the cell from death by necrosis or apoptosis and accelerate recovery. Significant advances have been made in studies relevant to plastic surgery regarding these proteins and their manipulation. This review introduces the heat shock proteins and appraises these studies in skin, ultraviolet light exposure, neoplasia, wound healing, ageing, burns, and reconstructive surgery.

Multicentric extra-abdominal desmoid tumours.

Despite their classification as benign, desmoid tumours are difficult to diagnose and manage. They are prone to recurrence and resection can be debilitating. Rarely, synchronous or metachronous multicentric desmoid tumours occur and may require further excision. Therefore, early detection of recurrence and multicentric tumours is vital. We present a case of metachronous desmoid tumours, and review the literature to propose a treatment pathway.

Cerebro-splanchnic oxygenation ratio (CSOR) using near infrared spectroscopy may be able to predict splanchnic ischaemia in neonates.

OBJECTIVE: To investigate whether near infrared spectroscopy (NIRS) can detect differences in oxyhaemoglobin signal when applied to the abdomens of neonates with surgically proven splanchnic ischaemia. DESIGN: Prospective, observational cohort study. SETTING: Tertiary neonatal referral centre. PATIENTS: Medical and surgical neonates were studied. Two groups were identified, neonates with acute abdomens referred for surgery and those with normal abdomens admitted for medical reasons. INTERVENTIONS: Tissue oxygenation indexes (TOI) of cerebral and splanchnic regions were measured using near infrared spectroscopy (NIRS) and their relative values expressed as a cerebro-splanchnic oxygenation ratio (CSOR). Measurements were made on admission or immediately prior to surgery and subsequently repeated on a daily basis, whenever possible, until discharge from our unit. The area under the receiver operating characteristic (ROC) curve was evaluated and optimum diagnostic cut-off values determined. RESULTS: Forty neonates were studied: 10 with acute abdomens, including four with necrotising enterocolitis (NEC), 29 controls with normal abdomens and one with cerebral hypoxic ischaemic injury. Median CSOR for the control group was 0.96 (interquartile range 0.83-1.02) whereas the acute abdomen group had a significantly lower median CSOR value of 0.66 (0.45-0.69) (p<0.001). The area under the ROC was 0.91 (95% confidence limits 0.78-1.00) for CSOR. Taking a boundary value of CSOR for the prediction of splanchnic ischaemia as less than 0.75, intestinal ischaemia was identified with a positive predictive value of 0.75 (0.43-0.95) and excluded with a negative predictive value of 0.96 (0.81-1.0). This was a better performance than using abdominal TOI alone. CONCLUSIONS: By comparing the TOI of cerebral and splanchnic regions it may be possible to establish the presence of normal splanchnic perfusion and detect when splanchnic ischaemia develops. CSOR had a 90% (56-100%) sensitivity to detect splanchnic ischaemia in neonates. Further work is necessary to confirm these early findings and establish whether abdominal NIRS has a clinical role in detecting splanchnic ischaemia.

Heat shock proteins delivered with a virus vector can protect cardiac cells against apoptosis as well as against thermal or hypoxic stress.

Over expression of heat shock proteins (hsps) by transfection of plasmid constructs in vitro and in transgenic animals in vivo can protect primary cardiac cells from subsequent exposure to severe thermal or hypoxic stress. Here we show that such protection can also be achieved by over-expressing the hsps using herpes simplex virus (HSV) vectors capable of efficient gene delivery in vivo. Moreover, the convenience and high efficiency of this system has allowed us to show, for the first time, that over-expression of hsp27 or hsp70 can protect cardiac cells against three different apoptosis-inducing stimuli as well as against thermal or hypoxic stress whereas hsp56 has no protective effect. The potential therapeutic use of inducing the over-expression of specific hsps in cardiac cells in vivo using pharmacological or gene therapy procedures is discussed.

Protection of neuronal cells from apoptosis by Hsp27 delivered with a herpes simplex virus-based vector.

Overexpression of the gene encoding the 70-kDa heat shock protein (hsp70) has previously been shown to protect neuronal cells against subsequent thermal or ischemic stress. It has no protective effect, however, against stimuli that induce apoptosis, although a mild heat shock (sufficient to induce hsp synthesis) does have a protective effect against apoptosis. We have prepared disabled herpes simplex virus-based vectors that are able to produce high level expression of individual hsps in infected neuronal cells without damaging effects. We have used these vectors to show that hsp27 and hsp56 (which have never previously been overexpressed in neuronal cells) as well as hsp70 can protect dorsal root ganglion neurons from thermal or ischemic stress. In contrast, only hsp27 can protect dorsal root ganglion neurons from apoptosis induced by nerve growth factor withdrawal, and hsp27 also protects the ND7 neuronal cell line from retinoic acid-induced apoptosis. However, hsp70 showed no protective effect against apoptosis in contrast to its anti-apoptotic effect in non-neuronal cell types. These results thus identify hsp27 as a novel neuroprotective factor and show that it can mediate this effect when delivered via a high efficiency viral vector.

Pure populations of transduced primary human cells can be produced using GFP expressing herpes virus vectors and flow cytometry.

Herpes simplex virus (HSV) has often been suggested as a vector for gene delivery to the nervous system although it is also capable of infecting many other cell types. HSV also has the ability to package large genetic insertions so the expression of multiple genes from a single virus is possible. Here we show that a green fluorescent protein (GFP) expressing HSV1 vector can transduce two primary human cell types--quiescent human CD34+ hematopoietic progenitor cells and dendritic cells--which are both hard to transduce by other means. We also show that GFP is an effective marker when expressed from an HSV vector in vivo in the mouse brain. When GFP is expressed together with a second gene (in this case lacZ) from a single virus, transduced GFP-positive CD34+ hematopoietic progenitor cells or dendritic cells can both be generated at an effective efficiency of 100% for the second gene. Here transduction with the vector is combined with flow cytometry allowing GFP-positive cells to be sorted from the untransduced population. Such completely transduced populations of quiescent CD34+ hematopoietic progenitor and dendritic cells cannot easily be achieved by other means, and might thus allow experimental or therapeutic protocols to be carried out requiring high-level transduction which would not otherwise be possible. Such an approach using HSV vectors might also be applicable to other cell types for which transduction is as yet unreliable or of low efficiency.

Delivery of a constitutively active form of the heat shock factor using a virus vector protects neuronal cells from thermal or ischaemic stress but not from apoptosis.

The heat shock proteins (HSPs) are induced by stressful stimuli and have a protective effect. Different HSPs protect with different efficiencies against different stresses indicating that optimal protection would be obtained with a non-stressful agent which induced a range of HSPs. We have prepared a herpesvirus vector expressing a constitutively active mutant form of heat shock factor 1 (HSF1) which, unlike the wild-type form of this transcription factor, does not require stress for its activation. Upon infection of neuronal cells, this virus induced a more restricted range of HSPs than in non-neuronal cells. Infection with the virus protected neuronal cells against subsequent thermal or ischaemic stress in accordance with its ability to induce HSP70 expression but did not protect them against apoptotic stimuli. The mechanisms of these effects and their significance for the use of HSF to manipulate HSP gene expression is discussed.

Increasing workload and changing referral patterns in paediatric cardiology outreach clinics: implications for consultant staffing.

OBJECTIVE: To assess the workload of, and referral patterns to, paediatric cardiology outreach clinics to provide data for future planning. DESIGN: Descriptive study of outpatient attendance during 1991 and 1996. SETTING: Five district general hospitals with unchanged local demographics and referral patterns during the study period. METHODS: Postal, telephone, and on site survey of clinic records and case notes. RESULTS: The number of outpatients increased by 61%, with a consequent increase in the number of clinics held and patients seen in each clinic. The number of patients aged between 10 and 15 years doubled. CONCLUSION: These data confirm the impression that demands for paediatric cardiology services are increasing. The increased need for attendance at outreach clinics has inevitable consequences for the clinical, teaching, and research activities of specialists in tertiary centres. An increase in the number of paediatric cardiologists, or development of local expertise (general paediatricians with an interest in cardiology), will be required. Furthermore, the increasingly large cohort of older teenagers and young adults with congenital heart disease underscores the need for the development of specialist facilities.

Gene transfer using a disabled herpes virus vector containing the EMCV IRES allows multiple gene expression in vitro and in vivo.

The design of recombinant HSV-1 vectors for delivery of transgenes to the central nervous system is undergoing constant development. Problems associated with the construction and use of such vectors include the requirement for detection of recombinant versus nonrecombinant virus in vitro and also the identification of transduced cells in vivo. This could be overcome by the insertion of reporter genes such as lacZ or green fluorescent protein (GFP) under a separate promoter to the transgene to be expressed. In this case, however, reporter gene expression does not necessarily confirm transgene expression as a separate RNA must be produced. This study reports the use of an encephalomyocarditis virus internal ribosome entry site (IRES) to enable the translation of two reporter genes from a single mRNA transcript driven by the same promoter within a disabled HSV vector, and discusses the potential advantages of this approach.

Focal cerebral ischaemia increases the levels of several classes of heat shock proteins and their corresponding mRNAs.

The induction of focal cerebral ischaemia in rats by middle cerebral artery occlusion has previously been shown to increase, over time, the mRNA levels of the heat shock proteins (HSPs) 27 and 70. However, the levels of HSP90 mRNA remain constant. In contrast, during global ischaemia, HSP70 and HSP90 mRNA levels are both raised, particularly in the CA1 neurons in the hippocampus, an area that is resistant to the insult in comparison to the surrounding regions. HSP27 mRNA is raised in the neuroglia in the subregions of the hippocampus. However, the protein levels of HSP27, 70 and 90 have not been characterised in focal ischaemia. With this data in mind, we have carried out a comparative study of HSP27, 56, 60, 70 and 90 mRNA and protein levels during focal cerebral ischaemia in rats, up to 24 h post-occlusion. We have shown that HSP70 and HSP27 mRNA levels are increased and also that HSP60 mRNA levels (which had also not previously been characterised in this model of focal ischaemia) are significantly raised. HSP90 and HSP56 mRNAs were not significantly elevated. On Western blot analysis, the inducible HSP72 protein was first detected at 8 h post-occlusion, HSP27 protein was detected only at 24 h post-occlusion and HSP60 protein, although constitutive, appeared to increase at 24 h post-occlusion. HSP56 protein levels appeared to rise on the occluded side, but HSP90 protein levels remained constant.