PrEP Use, Sexual Behaviour, and PrEP Adherence Among Men who have Sex with Men Living in Wales Prior to and During the COVID-19 Pandemic.

We examined PrEP use, condomless anal sex (CAS), and PrEP adherence among men who have sex with men (MSM) attending sexual health clinics in Wales, UK. In addition, we explored the association between the introduction of measures to control transmission of SARS-CoV-2 on these outcomes. We conducted an ecological momentary assessment study of individuals in receipt of PrEP in Wales. Participants used an electronic medication cap to record PrEP use and completed weekly sexual behaviour surveys. We defined adherence to daily PrEP as the percentage of CAS episodes covered by daily PrEP (preceded by ≥ 3 days of PrEP and followed by ≥ 2 days). Sixty participants were recruited between September 2019 and January 2020. PrEP use data prior to the introduction of control measures were available over 5785 person-days (88%) and following their introduction 7537 person-days (80%). Data on CAS episodes were available for 5559 (85%) and 7354 (78%) person-days prior to and following control measures respectively. Prior to the introduction of control measures, PrEP was taken on 3791/5785 (66%) days, there were CAS episodes on 506/5559 (9%) days, and 207/406 (51%) of CAS episodes were covered by an adequate amount of daily PrEP. The introduction of pandemic-related control measures was associated with a reduction in PrEP use (OR 0.44, 95%CI 0.20-0.95), CAS (OR 0.35, 95%CI 0.17-0.69), and PrEP adherence (RR = 0.55, 95%CI 0.34-0.89) and this may have implications for the health and wellbeing of PrEP users and, in addition to disruption across sexual health services, may contribute to wider threats across the HIV prevention cascade.

Platelets after burn injury - hemostasis and beyond.

Burn injuries are common and often life-threatening trauma. With this trauma comes an interruption of normal hemostasis, with distinct impacts on platelets. Our interest in the relationships between burn injury and platelet function stems from two key perspectives: platelet function is a vital component of acute responses to injury, and furthermore the incidence of cardiovascular disease (CVD) is higher in burn survivors compared to the general population. This review explores the impact of burn injury on coagulation, platelet function, and the participation of platelets in immunopathology. Potential avenues of further research are explored, and consideration is given to what therapies may be appropriate for mediating post-burn thrombopathology.

Clearance Prediction Methodology Needs Fundamental Improvement: Trends Common to Rat and Human Hepatocytes/Microsomes and Implications for Experimental Methodology.

Although prediction of clearance using hepatocytes and liver microsomes has long played a decisive role in drug discovery, it is widely acknowledged that reliably accurate prediction is not yet achievable despite the predominance of hepatically cleared drugs. Physiologically mechanistic methodology tends to underpredict clearance by several fold, and empirical correction of this bias is confounded by imprecision across drugs. Understanding the causes of prediction uncertainty has been slow, possibly reflecting poor resolution of variables associated with donor source and experimental methods, particularly for the human situation. It has been reported that among published human hepatocyte predictions there was a tendency for underprediction to increase with increasing in vivo intrinsic clearance, suggesting an inherent limitation using this particular system. This implied an artifactual rate limitation in vitro, although preparative effects on cell stability and performance were not yet resolved from assay design limitations. Here, to resolve these issues further, we present an up-to-date and comprehensive examination of predictions from published rat as well as human studies (where n = 128 and 101 hepatocytes and n = 71 and 83 microsomes, respectively) to assess system performance more independently. We report a clear trend of increasing underprediction with increasing in vivo intrinsic clearance, which is similar both between species and between in vitro systems. Hence, prior concerns arising specifically from human in vitro systems may be unfounded and the focus of investigation in the future should be to minimize the potential in vitro assay limitations common to whole cells and subcellular fractions.

A comparison of medication adherence/persistence for asthma and chronic obstructive pulmonary disease in the United Kingdom.

AIM: To describe and compare adherence and persistence with maintenance therapies in patients with asthma or chronic obstructive pulmonary disease (COPD) in the United Kingdom (UK). METHODS: A retrospective prescribing database cohort was obtained from 44 general practitioner surgeries in National Health Service Forth Valley Scotland. Patients with physician-diagnosed asthma or COPD who received maintenance therapy between January 2008 and December 2009 were included. Five classes of therapy were assessed: inhaled corticosteroids, long-acting beta-agonists, combination therapy inhalers, theophyllines and long-acting muscarinic antagonists. Adherence was calculated using the medication possession ratio (MPR) and persistence was determined using Kaplan-Meier survival analysis for the time to discontinuation (TTD) over 1 year. Two step-wise logistic regressions were performed to assess the contribution of diagnosis to adherence/persistence. RESULTS: A total of 13,322 patients were included in the analysis: 10,521 patients with asthma and 2801 patients with COPD. 25.2% of medication episodes for asthma and 45.6% of medication episodes for COPD were classified as having an adequate medication supply (MPR of 80-120%). The overall median TTD was 92 days (IQR, interquartile range: 50-186 days) for patients with asthma and 116 days (IQR: 58-259 days, comparison p < 0.001) for patients with COPD. Patients with COPD were found to be more likely to achieve an MPR of at least 80% (OR: 1.27, 95% CI: 1.15-1.40), but had a similar likelihood of persistence at 1 year to patients with asthma. CONCLUSION: Adherence and persistence with respiratory therapies in the UK is relatively low. There is suggestion that patients with COPD may display more adherent behaviours than patients with asthma.

The patient with acute muscular weakness.

Proximal muscle weakness can present acutely or subacutely to the Acute Medical Unit. Early diagnosis of the underlying pathology is essential due to life threatening complications such as respiratory failure and cardiac disturbances as well as causing significant levels of disability. The diagnosis requires thorough history-taking and examination to discern evidence of true weakness, assess its onset, distribution and severity followed by extensive investigations including a CK level, which if high should raise suspicion of rhabdomyolysis. Assessment of respiratory function should be done promptly to identify patients with associated respiratory muscle weakness and treatment should not be delayed waiting for definitive and confirmatory investigations. Poor response to treatment is unusual when diagnosis is correct; this raises the possibility of an alternative diagnosis.

Development of a value-based healthcare burns core set for adult burn care.

BACKGROUND: Value-based healthcare (VBHC) is increasingly implemented in healthcare worldwide. Transparent measurement of the outcomes most important and relevant to patients is essential in VBHC, which is supported by a core set of most important quality indicators and outcomes. Therefore, the aim of this study was to develop a VBHC-burns core set for adult burn patients. METHODS: A three-round modified national Delphi study, including 44 outcomes and 24 quality indicators, was conducted to reach consensus among Dutch patients, burn care professionals and researchers. Items were rated on a nine-point Likert scale and selected if ≥ 70% in each group considered an item 'important'. Subsequently, instruments quantifying selected outcomes were identified based on a literature review and were chosen in a consensus meeting using recommendations from the Dutch consensus-based standard set and the Dutch Centre of Expertise on Health Disparities. Time assessment points were chosen to reflect the burn care and patient recovery process. Finally, the initial core set was evaluated in practice, leading to the adapted VBHC-burns core set. RESULTS: Twenty-seven patients, 63 burn care professionals and 23 researchers participated. Ten outcomes and four quality indicators were selected in the Delphi study, including the outcomes pain, wound healing, physical activity, self-care, independence, return to work, depression, itching, scar flexibility and return to school. Quality indicators included shared decision-making (SDM), the number of patients receiving aftercare, determination of burn depth, and assessment of active range of motion. After evaluation of its use in clinical practice, the core set included all items except SDM, which are assessed by 9 patient-reported outcome instruments or measured in clinical care. Assessment time points included are at discharge, 2 weeks, 3 months, 12 months after discharge and annually afterwards. CONCLUSION: A VBHC-burns core set was developed, consisting of outcomes and quality indicators that are important to burn patients and burn care professionals. The VBHC-burns core set is now systemically monitored and analysed in Dutch burn care to improve care and patient relevant outcomes. As improving burn care and patient relevant outcomes is important worldwide, the developed VBHC-burns core set could be inspiring for other countries.

Development of a core outcome set for the evaluation of interventions to enhance trial participation decisions on behalf of adults who lack capacity to consent: a mixed methods study (COnSiDER Study).

BACKGROUND: Trials involving adults who lack capacity to provide consent rely on proxy or surrogate decision-makers, usually a family member, to make decisions about participation. Interventions to enhance proxy decisions about trial participation are now being developed. However, a lack of standardised outcome measures limits evaluation of these interventions. The aim of this study was to establish an agreed standardised core outcome set (COS) for use when evaluating interventions to improve proxy decisions about trial participation. METHODS: We used established methods to develop the COS including a consensus study with key stakeholder groups comprising those who will use the COS in research (researchers and healthcare professionals) and patients or their representatives. Following a scoping review to identify candidate items, we used a modified two-round Delphi survey to achieve consensus on core outcomes, with equivocal items taken to a consensus meeting for discussion. The COS was finalised following an online consensus meeting in October 2020. RESULTS: A total of 28 UK stakeholders (5 researchers, 10 trialists, 3 patient/family representatives, 7 recruiters and 3 advisors/approvers) participated in the online Delphi survey to rank candidate items from the scoping review (n = 36) and additional items proposed by participants (n = 1). Items were broadly grouped into three categories: how family members make decisions, their experiences of making decisions, and the personal aspects that influence the decision. Following the Delphi survey, 27 items were included and ten items exhibited no consensus which required discussion at the consensus meeting. Sixteen participants attended the meeting, including additional patient/family representatives invited to increase representation from this key group (n = 2). We reached consensus for the inclusion of 28 outcome items, including one selected at the consensus meeting. CONCLUSIONS: The study identified outcomes that should be measured as a minimum in all evaluations of interventions to enhance proxy decisions about trials. These relate to the process of decision-making, proxies' experience of decision-making, and factors that influence decision-making such as understanding. Further work with people with impairing conditions and their families is needed to explore their views about the COS and to identify appropriate outcome measures and timing of measurement. TRIAL REGISTRATION: The study is registered on the COMET database ( https://www.comet-initiative.org/Studies/Details/1409 ).

Factors influencing the implementation of best practice in burn care in Western Australia.

AIMS AND OBJECTIVES: The study aimed to determine the factors which influence clinician behaviour and adherence to best practice when clinicians provide the initial care for paediatric burn patients admitted to a burns unit. BACKGROUND: Optimal initial care of burn patients influences morbidity and mortality. Non-burn specialist clinician adherence to best practice is influenced by previously unexplored factors. DESIGN: General inductive qualitative methods were used to explore factors which influenced clinicians providing acute pre-admission burn care for children in Western Australia. METHODS: Interviews of nineteen clinicians using standardised open-ended questions based on the Gilbert Behaviour Engineering Model were used to collect data. RESULTS: The main influencing factors identified were the telehealth service which supported practice, whilst IT issues provided challenges to clinicians. CONCLUSION: Telehealth services support clinicians when providing burn care, however IT issues are an major barrier to both best practice and accessing the telehealth service and should be optimised to support clinical care IMPACT STATEMENT: What does this paper contribute to the wider global community? It provides burn clinicians with an insight into the factors which facilitate optimal care for patients prior to transfer to burn units, as well as the barriers faced by non-burn specialist clinicians when patients initially present for care. Models of care which acknowledge these factors can help facilitate optimal patient care.

Serial oxygen equilibrium and kinetic measurements during RBC storage.

OBJECTIVES: To contribute to the understanding of the biochemical changes associated with the RBC storage lesion. AIM: To investigate changes in O(2) equilibrium and on/off kinetic rates during routine cold storage. BACKGROUND: As RBCs are stored between 1 and 6°C numerous biochemical changes occur within the RBCs, including changes in the properties of the haemoglobin itself. This study serially analysed for the first time the O(2) equilibrium and on/off kinetic rates across the RBC membrane during routine storage. METHODS/MATERIALS: The oxygen binding (k(on) ) and offloading (k(off) ) constants were measured in fresh RBCs and then in AS-5-preserved RBCs at weekly intervals, along with oxygen equilibrium curves (OECs), 2,3-Diphosphoglycerate (2,3-DPG), p50 and the Hill number (n). RESULTS: The k(on) increased slightly as the 2,3-DPG and p50 decreased during storage, whereas the k(off) remained largely unchanged. The OECs demonstrated the expected increase in O(2) affinity, whereas the Hill number was unchanged during storage. CONCLUSION: In spite of the biochemical, structural and functional changes associated with the storage of RBCs, their in vitro interactions with oxygen were largely preserved through 42 days of storage.

Use of the Internet by burns patients, their families and friends.

INTRODUCTION: The Internet has also become an increasingly important source of health-related information. However, with this exponential increase comes the problem that although the volume of information is huge, the quality, accuracy and completeness of the information are questionable, not only in the field of medicine. Previous studies of single medical conditions have suggested that web-based health information has limitations. The aim of this study was to evaluate Internet usage among burned patients and the people accompanying them to the outpatient clinic. METHODS: A customised questionnaire was created and distributed to all patients and accompanying persons in the adult and paediatric burns clinics. This investigated computer usage, Internet access, usefulness of Internet search and topics searched. RESULTS: Two hundred and ten people completed the questionnaire, a response rate of 83%. Sixty three percent of responders were patients, parents 21.9%, spouses 3.3%, siblings, children and friends the remaining 10.8%. Seventy seven percent of attendees had been injured within the last year, 11% between 1 and 5 years previously, and 12% more than 5 years previously. Seventy four percent had computer and Internet access. Twelve percent had performed a search. Topics searched included skin grafts, scarring and scar management treatments such as pressure garments, silicone gel and massage. DISCUSSION: This study has shown that computer and Internet access is high, however a very small number actually used the Internet to access further medical information. Patients with longer standing injuries were more likely to access the Internet. Parents of burned children were more frequent Internet users. As more burn units develop their own web sites with information for patients and healthcare providers, it is important to inform patients, family members and friends that such a resource exists. By offering such a service patients are provided with accurate, reliable and easily accessible information which is appropriate to their needs.

Coherency image analysis to quantify collagen architecture: implications in scar assessment.

An important histological difference between normal, uninjured dermis and scar tissue such as that found in keloid scars is the pattern (morphological architecture) in which the collagen is deposited and arranged. In the uninjured dermis, collagen bundle architecture appears randomly organized (or in a basket weave formation), whereas in pathological conditions such as keloid scar tissue, collagen bundles are often found in whorls or in a hypotrophic scar collagen is more densely packed in a parallel configuration. In the case of skin, a scar disables the dermis, leaving it weaker, stiff and with a loss of optimal functionality. The absence of objective and quantifiable assessments of collagen orientation is a major bottleneck in monitoring progression of scar therapeutics. In this article, a novel quantitative approach for analyzing collagen orientation is reported. The methodology is demonstrated using collagen produced by cells in a model scar environment and examines collagen remodeling post-TGFß stimulation in vitro. The method is shown to be reliable and effective in identifying significant coherency differences in the collagen deposited by human keloid scar cells. The technique is also compared for analysing collagen architecture in rat sections of normal, scarred skin and tendon tissue. Results demonstrate that the proposed computational method provides a fast and robust way of analyzing collagen orientation in a manner surpassing existing methods. This study establishes this methodology as a preliminary means of monitoring in vitro and in tissue treatment modalities which are expected to alter collagen morphology.

The QuickDASH is an appropriate tool for measuring the quality of recovery after upper limb burn injury.

BACKGROUND: Upper limb (UL) burns commonly result in significant dysfunction. The measurement of disability is vital to assess recovery after burn injury. The QuickDASH questionnaire was developed to evaluate UL disorders. The aim of this study was to evaluate its validity, repeatability and responsiveness for burn patients. METHODS: In 2006, 85 patients with UL burns were recruited at Royal Perth Hospital. Each completed both QuickDASH and Burns Specific Health Scale-Brief (BSHS-B) at regular intervals after their burn. Further, 67 patients repeated the questionnaire 1 day after completing it at discharge. RESULTS: Validity-Criterion validity was demonstrated between QuickDASH and BSHS-B through good correlations (r(2)=-0.79 to -0.89). Construct validity was demonstrated using burn severity markers. QuickDASH scores significantly differed when grouped according to major burn, full thickness burn, surgery and need for hospital admission. Repeatability-QuickDASH showed excellent repeatability (ICC=0.93). Responsiveness-Effect size of QuickDASH was demonstrated to be greater than BSHS-B at all measurement points. CONCLUSIONS: This longitudinal study confirms the validity, repeatability and responsiveness of the QuickDASH outcome measure in patients with upper limb burns. It supports the use of the QuickDASH in this population to help assess change in functional level.

Burns first aid information on the Internet.

The Internet is an increasingly important source of health-related information. However, the growth of the Internet and its use as a medical delivery tool should be viewed with caution. One of the key concerns is that although the volume of information is huge, the quality, accuracy and completeness of the information is questionable. The aim of this study was to evaluate burns first aid information on the Internet. The search term used was "first aid for burns" and the first 25 hits from each search engine were analysed by one of the observers. We gathered basic information on the web sites--such as the country of origin, language in which the information was offered, accessibility, relevance and whether the site was commercial, organisational or academic. Quality and technicality of the web sites were assessed and scored. The mean quality score was 4.7/15 (31.5%) The mean technical score was 6.1 of 12 (51.1%). When the total score was categorised by percentage, none of the web sites ranked in the excellent category, 1 was very good, 4 were good, 6 were fair and the majority, 36, were poor. Based on the quality score only, two web sites were in the excellent category and two were very good. For technicality one web site was excellent and three were very good. This study has shown first aid information on the Internet is largely of poor quality, that the technical information provided is inadequate and that the sites include a significant amount of grossly inaccurate information. The few sites that contain excellent technical information make up a very small proportion of what is available. Therefore, the average Internet user may not encounter these resources, instead gaining knowledge from sites of questionable value.

The use of cultured epithelial autograft in the treatment of major burn wounds: eleven years of clinical experience.

INTRODUCTION: In patients with burns involving over 50% total body surface area (TBSA), donor skin is limited. Tissue engineering, particularly cultured epithelial autograft (CEA), offers a potential solution to assist in expedient wound closure. MATERIALS AND METHODS: Prior to 1994, the application of CEA was restricted to confluent cell sheets. The introduction of an autologous cell suspension (CellSpray) in 1994 enabled cells to be delivered to the wound via aerosol onto debrided burn and donor skin graft wound areas. This retrospective clinical audit of major burn injured patients (n=84) describes the use of CEA in those with over 50%TBSA in Western Australia (WA) between 1992 and 2002. RESULTS: The initial introduction of CEA was as confluent sheets, as this evolved to the use of CEA in suspension there was a reduction in the required surgical intervention and total length of stay (TLOS) divided by %TBSA. DISCUSSION: With the audit covering an 11-year period, many facets of clinical burn care have evolved. The WA experience has demonstrated CEA has been positively integrated into clinical practice in association with traditional wound care techniques of skin grafting to augment wound healing.

The use of cultured epithelial autograft in the treatment of major burn injuries: a critical review of the literature.

INTRODUCTION: The need to achieve rapid wound closure in patients with massive burns and limited skin donor sites led to the investigation of in vitro cellular expansion of keratinocytes. The use of cultured epithelial autografts (CEA) was first reported in the treatment of major burns in 1981. Since that time, support for the use of CEA has varied, ranging from 'a useful agent' to having 'no demonstrable effect on the outcome of extensively burned patients'. METHODS: This critical review of the literature examines issues associated with the use of CEA and the introduction of the technology into clinical practice. The factors potentially limiting the use of cultured CEA are the time necessary to culture CEA sheets, the reliability of 'take', vulnerability of grafts on the newly healed surface, long-term durability and the cost implications of such treatment. The available literature was located and critically evaluated using the Australian National Health and Medical Research Council Guidelines. FINDINGS: In the identified literature, the level of evidence to support the use of CEA in major burn injures is limited and often restricted to case studies and case series with no Level 1 evidence currently available. CONCLUSION: The main question arising 'Does CEA have a role in the treatment of major burns?' has proven difficult to answer due to the wide variation in both the quality of study design and the findings. At best, the literature review has highlighted areas of concern that have hindered the successful use of CEA. Our review critically evaluates the use of CEA and explores the advances in techniques towards attempting to improve reliable clinical implementation of CEA. The need for higher level research into the use of CEA is emphasised by this review.

Infection in acute burn wounds following the Bali bombings: a comparative prospective audit.

INTRODUCTION: Bacterial colonisation and invasive bacterial infection remain the major causes of mortality and morbidity following severe burn thus ongoing surveillance of patients and monitoring of infection facilitates early intervention to minimise the risk of sepsis. The circumstances of the Bali bombings in October 2002, provided an opportunity to analyse the ramifications of lengthy transfer times, delayed resuscitation and topical treatment, on the primary incidence of burn wound infection (BWI). METHOD: This prospective clinical audit investigated the primary incidence of BWI between the usual burn patients admitted to the Burn Unit at Royal Perth Hospital, Western Australia, and a number of survivors from the Bali bombings during a 3-month audit period in 2002. BWI was identified using the Peck et al. proposed definitions for the surveillance of burn wound infections. These include impetigo, surgical wound related infection, cellulitis and invasive infection of unexcised wounds. RESULTS: The incidence of primary BWI in the Bali-tourist group (68.2%) compared with the standard WA group (18.2%) was significant (p=0.001). CONCLUSION: Sensitive assessment criteria allowed for early identification of wound infection. A clinically significant difference in the Bali-tourist group is probably related to the circumstances of their injury.

Fatty acid synthase (FAS): a target for cytotoxic antimetabolites in HL60 promyelocytic leukemia cells.

Many human cancers express elevated levels of fatty acid synthase (FAS), with correspondingly increased fatty acid synthesis and abnormal fatty acid utilization. Recent studies have shown that the FAS inhibitor, cerulenin, is selectively cytotoxic to cell lines derived from human malignancies, suggesting that those carcinoma cells are dependent upon endogenous fatty acid synthesis for growth. These data further suggest that the fatty acid synthesis pathway is a potential target for chemotherapy development. The present studies demonstrate that cerulenin cytotoxicity is mediated by fatty acid pathway inhibition. Proliferating HL60 promyelocytic leukemia cells express high levels of FAS mRNA and protein and synthesize fatty acid predominantly for membrane phospholipid. Following exposure to 12-O-tetradecanoylphorbol-13-acetate, the FAS expression in HL60 cells is abolished, fatty acid synthesis diminishes, and the cells become insensitive to cerulenin while acquiring a differentiated, macrophage-like phenotype. HL60 cells adapted to growth in serum- and fatty acid-free medium show a dose-dependent sensitivity to cerulenin, which is reversed by palmitate, the major product of FAS, indicating that cerulenin cytotoxicity is mediated through fatty acid starvation. Cells grown in the presence of exogenous fatty acid partially downmodulate FAS expression and increase mean cell volume (phospholipid mass/cell) but retain their sensitivity to cerulenin, which is reversed by 3-fold excess oleate supplementation. These results demonstrate that malignant cells can retain dependence on endogenous fatty acid synthesis and sensitivity to FAS inhibitors in the presence of physiological fatty acid levels and thus support the notion that FAS inhibitors may be useful in treating cancer in vivo.

Inhibition of fatty acid synthesis induces programmed cell death in human breast cancer cells.

One of the key limiting factors in the treatment of advanced stage human epithelial malignancies is the lack of new, selective molecular targets for antineoplastic therapy. A substantial subset of human breast, ovarian, endometrial, colorectal, and prostatic cancers express elevated levels of fatty acid synthase, the major enzyme required for endogenous fatty acid biosynthesis, and carcinoma lines are growth inhibited by cerulenin, a noncompetitive inhibitor of fatty acid synthase. We have shown previously that the difference in fatty acid biosynthesis between cancer and normal cells is an exploitable target for metabolic inhibitors in the in vitro setting and in vivo in a human ovarian carcinoma xenograft in nude mice. Here, we report that cerulenin treatment of human breast cancer cells inhibits fatty acid synthesis within 6 h after exposure, that loss of clonogenic capacity occurs within the same interval, and that DNA fragmentation and morphological changes characteristic of apoptosis ensue.

Inhibition of fatty acid synthesis delays disease progression in a xenograft model of ovarian cancer.

One of the key limiting factors in the treatment of advanced stage human epithelial malignancies is the lack of selective molecular targets for antineoplastic therapy. A substantial subset of human ovarian, endometrial, breast, colorectal, and prostatic cancers exhibit increased endogenous fatty acid biosynthesis and overexpress certain enzymes in the pathway. Cell lines derived from these tumors use endogenously synthesized fatty acids for cellular functions, whereas normal cells and tissues appear to utilize dietary lipids preferentially. We have previously shown that the difference in fatty acid biosynthesis between cancer and normal cells is an exploitable target for metabolic inhibitors in vitro. Here, we report observations in vivo using the i.p. model of the multiply drug-resistant OVCAR-3 human ovarian carcinoma in nude mice which demonstrate that: (a) fatty acid synthase overexpression in OVCAR-3 is comparable to levels in primary human tumors assessed by immunohistochemistry; (b) fatty acid synthetic activity of OVCAR-3 is comparably elevated in vitro and in vivo and is 4 to >20-fold higher than normal murine tissues; (c) treatment with the specific fatty acid synthase inhibitor, cerulenin, markedly reduces tumor cell fatty acid biosynthesis in vivo; (d) fatty acid synthase inhibition produces regression of established ascites tumor; and (e) treatment with cerulenin causes reduction in ascites incidence, delay in onset of ascites, and significantly increased survival (P<0.04).

Effects of hypoxia and glutathione depletion on hemoglobin- and myoglobin-mediated oxidative stress toward endothelium.

We investigated the toxicity of hemoglobin/myoglobin on endothelial cells under oxidative stress conditions that include cellular hypoxia and reduced antioxidant capacity. Bovine aorta endothelial cells (BAECs), grown on microcarrier beads, were subjected to cycles of hypoxia and reoxygenation in a small volume of medium, and endothelial cell monolayers were depleted of their intracellular glutathione (GSH) by treatment with buthionine sulfoximine. Incubation of diaspirin cross-linked hemoglobin (DBBF-Hb) or horse skeletal myoglobin (Mb) with BAECs subjected to 3 h of hypoxia caused transient oxidation of the hemoproteins to the ferryl form (Fe(4+)). Formation of the ferryl intermediate was decreased in a concentration-dependent manner by the addition of L-arginine, a substrate of NO synthase, after 3 h of hypoxia. Optimal inhibition of ferryl formation, possibly due to the antioxidant action of NO, was achieved with 900 microM L-arginine. Addition of hydrogen peroxide to GSH-depleted cells in the presence of DBBF-Hb or Mb significantly decreased cell viability. Ferryl Mb, but not ferryl DBBF-Hb, was observed in samples analyzed at the end of treatment, which may explain the greater toxicity observed with Mb as opposed to DBBF-Hb. This model may be utilized to identify causative agent(s) associated with hemoprotein cytotoxicity and in designing strategies to suppress or control heme-mediated injury under physiologically relevant conditions.