Measuring pressure under burns pressure garments using the Oxford Pressure Monitor

Pressure garments are used extensively in the treatment of hypertrophic scarring following burn injuries. The Oxford Pressure Monitor was used to measure garment-scar interface pressure (mmHg) using a number of fabric types over various body parts. The results indicate a wide range of pressure values between different garments and body parts with the greatest pressures found over the dorsum of hands and feet. The problems of achieving 'optimal pressure' over hypertrophic scarring are discussed with emphasis on the need for more accurate measuring equipment.     

Guidelines for the collection, processing and storage of human bone marrow and peripheral stem cells for transplantation

SUMMARY. There are no current U.K. or international guidelines or regulations covering the production, processing and storage of haemopoietic cells such as to allow their engraftment following myeloablative therapy. This paper seeks to provide such guidelines. It enumerates how quality control and assurance can be applied to this area of transfusion medicine; procedural steps relating to bone marrow harvest on peripheral blood stem cell collection are outlined and recommended doses of nucleated cells suggested for both procedures. General specifications for identification, storage and transportation of bone marrow and peripheral blood stem cells are included and specific laboratory procedures related to the provision of haemopoietic cells for engraftment are outlined. Umbilical cord blood transplants and long-term bone marrow culture are alluded to but these are still in a research phase.     

Epidemiology of industrial burns in Brisbane

A retrospective epidemiological study of industrial burns admitted to the Royal Brisbane Hospital was conducted over a period of 7 years. A total of 182 patients were included in this survey--173 males (95 per cent) and 9 females (5 per cent). The proportion of industrial burns has decreased from 31.5 per cent to 18.5 per cent of total admissions to the burns unit over the past 10 years. Fifty per cent of the burns occurred in males less than 30 years old. The average age was 31 years. Two-thirds of the burns covered less than 10 per cent of the body and 84 per cent covered less than 20 per cent. While scalds were the commonest cause of industrial burns in our study (19.4 per cent), flame burns with clothing ignited caused the most extensive burns. Face and hands were the most common sites involved. Burns to these regions were mainly caused by flame and electrical burns. Eye burns comprised 5.5 per cent of the sample and were due to chemicals, gas explosions and electric flash. Twenty-six patients (14 per cent) suffered respiratory injury. Only one patient out of our series of 182 died. Progress has been made in industrial safety in the past few years but carelessness and human error still take their toll.     

The mechanism of action of retrograde oxygen persufflation in renal preservation

Vascular perfusion of gaseous oxygen has been used to prolong the in vitro survival of a number of isolated organs, and has been shown to improve the hypothermic preservation of ischemically injured kidneys that were subsequently transplanted. We have investigated the mechanism of this effect. Rabbit kidneys were subjected to 60 min of warm ischemia prior to preservation for 24 hr with Ross, Marshall, and Escott's hypertonic citrate solution, with or without retrograde oxygen persufflation (ROP) via the renal vein. It was found that adenine nucleotide levels were almost doubled in the ROP-preserved kidneys, principally due to higher adenosine triphosphate (ATP) concentrations. It was shown that cytochrome oxidase activity was unaffected by ischemia or preservation method, but studies with the metabolic inhibitors ouabain and a mixture of cyanide and iodoacetate suggested that ATP was being synthesized during the storage period but was also being utilized to power the active volume-regulating pump. Morphological examination revealed a much greater degree of cell swelling and cytological injury in the kidneys not subject to ROP, and the interstitial space appeared much reduced in the latter group. At the ultrastructural level, the ROP-treated kidneys showed generally well-preserved mitochondria, mostly in the energized "orthodox" configuration. In contrast, the mitochondria in the nonpersufflated kidneys were generally in the "condensed" deenergized state. We conclude that the provision of sufficient oxygen by ROP allows the continued production of ATP in sufficient quantities to permit improved maintenance of cellular volume and morphology under the conditions of low-temperature storage that we have studied.     

Permeation of human ovarian tissue with cryoprotective agents in preparation for cryopreservation

The recent improvements in the treatment of cancer by chemo- and radiotherapy have led to a significant increase in the survival rates of patients with malignant disease, but at the expense of distressing side effects. One major problem, especially for younger patients, is that aggressive therapy destroys a significant proportion of the follicular population, which can result in either temporary or permanent infertility. Freeze-banking pieces of ovarian cortex prior to treatment is one strategy for preserving fecundity. When the patient is in remission, fertility could, theoretically, be restored by autografting the thawed tissue at the orthotopic site or by growing isolated follicles to maturity in vitro. Recent studies have found good follicular survival in frozen-thawed human ovarian tissue but to optimize the process an effective cryopreservation method needs to be developed. An essential part of such a technique is to permeate the tissue with a cryoprotectant to minimize ice formation and the extent of this equilibration is an important determinant of post-thaw cellular survival. In the current study, we have investigated the diffusion of four cryoprotective agents into human tissue at both 4 degrees C and 37 degrees C. We have also studied the effect of adding different concentrations of the non penetrating cryoprotective agent, sucrose, to the freezing media using the release of lactate dehydrogenase as a measure of its protective effect. At 4 degrees C propylene glycol and glycerol penetrated the tissue significantly slower than either ethylene glycol or dimethyl sulphoxide. At the higher temperature of 37 degrees C all four cryoprotectants penetrated at a faster rate, however concern about enhanced toxicity prevents the use of these conditions in practice. Thus, the results suggest that the best method of preparing tissue for freezing is exposure for 30 min to 1.5 M solutions of ethylene glycol or dimethyl sulphoxide at 4 degrees C; this achieved a mean tissue concentration that was almost 80% that of the bathing solution. We also report that the addition of low concentrations of sucrose to the freezing medium does not have a significant protective effect against freezing injury.      

Polyamine metabolism during cardiac hypertrophy

Treatment with thyroxine for 7 days to produce myocardial hypertrophy led to an increase in the content of putrescine, spermidine, and spermine in the rat heart. The content of decarboxylated S-adenosylmethionine, the source of the aminopropyl groups needed for polyamine synthesis, was increased by the thyroxine treatment as were the activities of ornithine and S-adenosylmethionine decarboxylases. The enhanced S-adenosylmethionine decarboxylase activity measured in vitro was due to an increase in the amount of enzyme protein as measured by immunotitration with a specific antiserum. In vivo, decarboxylation of S-adenosylmethionine was, therefore, increased both by the increased amount of enzyme protein and by the elevated concentration of putrescine (which activates the enzyme) brought about by the enhanced ornithine carboxylase activity. Spermine synthase did not change significantly during the treatment and spermidine synthase increased only slightly. Therefore, the accumulation of polyamines was mediated predominantly via the increased availability of both putrescine and decarboxylated S-adenosylmethionine. Administration of 1,3-diamino-2-propanol led to a rapid reduction in the activity of ornithine decarboxylase in the heart, and continued exposure to this substance by its inclusion in the drinking water completely prevented the increase in concentration of putrescine and polyamines in response to thyroxine. However, cardiac hypertrophy as measured by the increase in cardiac mass was not prevented by such treatment with 1,3-diaminopropanol, showing that the increased content of polyamines was not essential for the hypertrophic response.     

Cytokines, thyroid autoantibody synthesis and thyroid cell survival in culture

In autoimmune thyroid disease lymphoid cells infiltrating the thyroid gland occur in conspicuous aggregates or as a diffusely distributed population invading the thyroid follicles. Consequently cytokines secreted by activated T cells or macrophages could influence neighbouring thyroid cells as well as other lymphocytes. We have investigated this possibility using recombinant cytokines. Thyroid cell survival was assessed in terms of mitochondrial dehydrogenase activity in monolayers exposed to tumour necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), interleukin-1 (IL-1 alpha and beta) and interleukin-2 (IL-2) in the presence or absence of thyroid-stimulating hormone (TSH). Neither TNF-alpha nor IL-2 affected thyroid cell survival, IFN-gamma was usually inhibitory and IL-1 alpha slightly enhanced cell survival in some experiments. However, the effects were small and variable and were not enhanced by potentially synergistic combinations of cytokines, longer periods of exposure, or different culture conditions. In contrast, IFN-gamma, IL-2 and TNF-alpha inhibited the ability of thyroid lymphocytes from patients with Graves' disease and Hashimoto's thyroiditis to synthesize autoantibodies to thyroid peroxidase (TPO) and thyroglobulin (Tg). Comparison of lymphoid populations isolated by digestion and/or mechanical disaggregation indicated that a population of activated B cells, plasma cells and T cells, intimately associated with thyroid cells since they could only be extracted by digestion, was influenced by cytokines. Our studies suggest that in addition to its well-recognized ability to induce MHC class II antigens on thyroid cells, IFN-gamma may inhibit thyroid cell proliferation and TNF-alpha, IFN-gamma and IL-2 may down-regulate thyroid autoantibody synthesis.     

Preservation of ischemically injured canine kidneys by retrograde oxygen persufflation

Canine kidneys were briefly perfused with Ross and Marshall's hypertonic citrate solution and stored at O C. This study concerns the effect, during such storage, of insufflating various gases via the renal vein and allowing the gas to escape through needle perforations of the renal surface. We were able to confirm the finding of Ross and Escott that kidneys that have suffered 30 min of warm ischemia prior to preservation, will, if oxygen is so "persufflated" during 24 hr storage, provide life-supporting function when subsequently auto-grafted. Moreover, we were able to extend the preservation period to 48 hr after 30 min warm ischemia, and to achieve 24-hr preservation after 60 min of warm ischemia. Oxygen was essential: our results suggest that air is less effective than pure oxygen, and we found inert gases to be completely ineffective. Uniformly high oxygen tensions were measured throughout the kidneys during storage, but we were unable to demonstrate any resynthesis of adenosine triphosphate and adenosine diphosphate. The mechanism responsible for the effectiveness of retrograde oxygen persufflation remains obscure.     

Aeromonas wound infection in burns

Infection of burn patients with the Aeromonas organism is an uncommon event. This paper documents four cases of Aeromonas hydrophila and one case involving both A. hydrophila and A. caviae occurring in burn patients between 1990 and 1998 at the Royal Brisbane Hospital burns unit. The organism was isolated from either skin swabs, tissue samples, blood cultures or cultured lines. In all patients there was a history of immersion in water immediately post burn. There is one case of invasion and destruction of deeper tissues and one fatality. Appropriate management requires a high index of suspicion if a history of immersion in untreated water post burn is given and the treatment involves aggressive excision and antibiotic therapy.