Limb presentations of invasive Group A Streptococci infection in children

Infections with invasive Group A streptococcus can have a wide range of presentations and be life threatening if not diagnosed and managed rapidly. Limb presentations in children can be especially challenging and we present our experience to help manage such cases. There can be multiple foci of infection with seeding to avascular structures. Therefore, we advocate maintaining a high degree of clinical suspicion when assessing this group of patients, who are often critically unwell, and have varying presentation. Early and aggressive surgical intervention may be key for disease control.

713 Use of A Pre-Operative Investigation Checklist in Plastic Surgery Trauma

Introduction

In a regional centre for plastic surgery, it had been noted that operations were being delayed due to lack of pre-operative investigations. A pre-operative investigation checklist was developed between anaesthetic and surgical staff for semi-elective plastic trauma surgery patients, based on NICE guidelines. The checklist recommends which blood, radiology and cardiopulmonary tests would be appropriate based upon age, ASA grade and co-morbidity.

Method

A complete cycle audit was used to evaluate the checklist. All patients having GA/block for plastic surgery trauma in a 2-week window were included. Data was collected retrospectively via electronic operative records, anaesthetic assessments, and clinical notes. A minimum of 15 patients was collected per cycle. A single page pre-operative checklist was created for pre-operative investigations were introduced after the first cycle.

Results

The first audit cycle had 16 patients, ASA1 (5), ASA 2(6) ASA 3 (5). 75% had appropriate pre-op investigations. In the second cycle 22 patients, ASA 1 (8), ASA 2 (9), ASA 3 (3), ASA 4 (1). 100% of patients had appropriate pre-operative investigations.

Conclusions

There was increased awareness of pre-operative investigations in medical and nursing staff after the introduction of the checklist. It has helped streamline the delivery of semi-elective trauma surgery in our unit.

A phase I dose-escalation study of enzalutamide in combination with the AKT inhibitor AZD5363 (capivasertib) in patients with metastatic castration-resistant prostate cancer

BACKGROUND

Activation of the PI3K/AKT/mTOR pathway through loss of phosphatase and tensin homolog (PTEN) occurs in approximately 50% of patients with metastatic castration-resistant prostate cancer (mCRPC). Recent evidence suggests that combined inhibition of the androgen receptor (AR) and AKT may be beneficial in mCRPC with PTEN loss.

PATIENTS AND METHODS

mCRPC patients who previously failed abiraterone and/or enzalutamide, received escalating doses of AZD5363 (capivasertib) starting at 320 mg twice daily (b.i.d.) given 4 days on and 3 days off, in combination with enzalutamide 160 mg daily. The co-primary endpoints were safety/tolerability and determining the maximum tolerated dose and recommended phase II dose; pharmacokinetics, antitumour activity, and exploratory biomarker analysis were also evaluated.

RESULTS

Sixteen patients were enrolled, 15 received study treatment and 13 were assessable for dose-limiting toxicities (DLTs). Patients were treated at 320, 400, and 480 mg b.i.d. dose levels of capivasertib. The recommended phase II dose identified for capivasertib was 400 mg b.i.d. with 1/6 patients experiencing a DLT (maculopapular rash) at this level. The most common grade ≥3 adverse events were hyperglycemia (26.7%) and rash (20%). Concomitant administration of enzalutamide significantly decreased plasma exposure of capivasertib, though this did not appear to impact pharmacodynamics. Three patients met the criteria for response (defined as prostate-specific antigen decline ≥50%, circulating tumour cell conversion, and/or radiological response). Responses were seen in patients with PTEN loss or activating mutations in AKT, low or absent AR-V7 expression, as well as those with an increase in phosphorylated extracellular signal-regulated kinase (pERK) in post-exposure samples.

CONCLUSIONS

The combination of capivasertib and enzalutamide is tolerable and has antitumour activity, with all responding patients harbouring aberrations in the PI3K/AKT/mTOR pathway.

CLINICAL TRIAL NUMBER

NCT02525068.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Enterovirus 71 outbreak in Northern Sydney, 2013: case series and initial response

AIM

Enteroviruses are a common cause of childhood disease which may manifest in a variety of ways. Enterovirus 71 (EV71) is a subtype of enterovirus which can cause meningoencephalomyelitis resulting in neurological sequelae including lethargy, weakness, ataxia, sleep myoclonus, urinary retention and, in severe cases, cardiorespiratory collapse due to neurogenic pulmonary oedema. EV71 was responsible for outbreaks in South East Asia in 1997-1998, in Western Australia in 1999 and in Sydney in 2000-2001. In 2013, we are experiencing another EV71 outbreak in Sydney. This study describes the discovery of a new outbreak in Sydney's Northern Beaches, the clinical findings as well as the public health response.

METHODS

Thirty-seven children in total presented with presumed EV71 to the Northern Beaches Health Service from December 2012 to April 2013. Most children presented with a prodrome lasting 2-7 days prior to seeking medical attention. Sleep myoclonus was a common presenting sign occurring in 65%. Neurological signs were subtle in the majority of children and were at times missed by clinicians on a child's first presentation. Forty-six per cent of children who presented to Northern Beaches Health Service during this outbreak required a transfer to a tertiary paediatric centre for more intensive care.

RESULTS

The public health investigation was important in establishing that the disease was widespread throughout the community and not as a result to exposure to a single child care setting. Identification of risk factors enabled more targeted communication to medical practitioners, child care centres and parents within the local community.

CONCLUSIONS

EV71 is in Australia and all clinicians seeing children in primary, secondary and tertiary care centres need to be aware of the disease, the subtle nature of initial symptoms and the potentially devastating consequences.

Fate of pathologically bound oxygen resulting from inhalation of labeled ozone in rats

Inhaled ozone (O3) reacts chemically with respiratory tract biomolecules where it forms covalently bound oxygen adducts. We investigated the fate of these adducts following inhalation exposure of rats to labeled ozone ((18)O3, 2 ppm, 6 hr or 5 ppm, 2 hr). Increased (18)O was detected in blood plasma at 7 hr post exposure and was continuously present in urine for 4 days. Total (18)O excreted was ~53% of the estimated amount of (18)O3 retained by the rats during (18)O3 exposure suggesting that only moderate recycling of the adduct material occurs. The time course of excretion, as well as properties of the excreted (18)O were determined to provide guidance to future searches for urinary oxidative stress markers. These results lend plausibility to published findings that O3 inhalation could exert influences outside the lung, such as enhancement of atherosclerotic plaques.

Biomarkers of Dose and Effect of Inhaled Ozone in Resting versus Exercising Human Subjects: Comparison with Resting Rats

To determine the influence of exercise on pulmonary dose of inhaled pollutants, we compared biomarkers of inhaled ozone (O₃) dose and toxic effect between exercise levels in humans, and between humans and rats. Resting human subjects were exposed to labeled O₃ (¹⁸O₃, 0.4 ppm, for 2 hours) and alveolar O₃ dose measured as the concentration of excess ¹⁸O in cells and extracellular material of nasal, bronchial, and bronchoalveolar lavage fluid (BALF). We related O₃ dose to effects (changes in BALF protein, LDH, IL-6, and antioxidant substances) measurable in the BALF. A parallel study of resting subjects examined lung function (FEV₁) changes following O₃. Subjects exposed while resting had ¹⁸O concentrations in BALF cells that were 1/5th of those of exercising subjects and directly proportional to the amount of O₃ breathed during exposure. Quantitative measures of alveolar O₃ dose and toxicity that were observed previously in exercising subjects were greatly reduced or non-observable in O₃ exposed resting subjects. Resting rats and resting humans were found to have a similar alveolar O₃ dose.

Nitric oxide and superoxide mediate diesel particle effects in cytokine-treated mice and murine lung epithelial cells--implications for susceptibility to traffic-related air pollution

Background

Epidemiologic studies associate childhood exposure to traffic-related air pollution with increased respiratory infections and asthmatic and allergic symptoms. The strongest associations between traffic exposure and negative health impacts are observed in individuals with respiratory inflammation. We hypothesized that interactions between nitric oxide (NO), increased during lung inflammatory responses, and reactive oxygen species (ROS), increased as a consequence of traffic exposure ─ played a key role in the increased susceptibility of these at-risk populations to traffic emissions.

Methods

Diesel exhaust particles (DEP) were used as surrogates for traffic particles. Murine lung epithelial (LA-4) cells and BALB/c mice were treated with a cytokine mixture (cytomix: TNFα, IL-1β, and IFNγ) to induce a generic inflammatory state. Cells were exposed to saline or DEP (25 μg/cm²) and examined for differential effects on redox balance and cytotoxicity. Likewise, mice undergoing nose-only inhalation exposure to air or DEP (2 mg/m³ × 4 h/d × 2 d) were assessed for differential effects on lung inflammation, injury, antioxidant levels, and phagocyte ROS production.

Results

Cytomix treatment significantly increased LA-4 cell NO production though iNOS activation. Cytomix +  DEP-exposed cells incurred the greatest intracellular ROS production, with commensurate cytotoxicity, as these cells were unable to maintain redox balance. By contrast, saline + DEP-exposed cells were able to mount effective antioxidant responses. DEP effects were mediated by: (1) increased ROS including superoxide anion (O₂˙^-), related to increased xanthine dehydrogenase expression and reduced cytosolic superoxide dismutase activity; and (2) increased peroxynitrite generation related to interaction of O₂˙^- with cytokine-induced NO. Effects were partially reduced by superoxide dismutase (SOD) supplementation or by blocking iNOS induction. In mice, cytomix +  DEP-exposure resulted in greater ROS production in lung phagocytes. Phagocyte and epithelial effects were, by and large, prevented by treatment with FeTMPyP, which accelerates peroxynitrite catalysis.

Conclusions

During inflammation, due to interactions of NO and O₂˙^-, DEP-exposure was associated with nitrosative stress in surface epithelial cells and resident lung phagocytes. As these cell types work in concert to provide protection against inhaled pathogens and allergens, dysfunction would predispose to development of respiratory infection and allergy. Results provide a mechanism by which individuals with pre-existing respiratory inflammation are at increased risk for exposure to traffic-dominated urban air pollution.

Susceptibility of inflamed alveolar and airway epithelial cells to injury induced by diesel exhaust particles of varying organic carbon content

Exposure to traffic-related ambient air pollution, such as diesel exhaust particles (DEP), is associated with adverse health outcomes, especially in individuals with preexisting inflammatory respiratory diseases. Using an analogous novel in vitro system to model both the healthy and inflamed lung, the susceptibility of epithelial cells exposed to DEP of varying organic carbon content was studied. Murine LA-4 alveolar type II-like epithelial cells, as well as primary murine tracheal epithelial cells (MTE), were treated with exogenous cytokines (tumor necrosis factor [TNF] alpha + interleukin [IL]-1 beta + interferon [IFN] gamma) to model a mild inflammatory state. Epithelial cells were subsequently exposed to DEP of varying organic carbon content, and the resultant cytotoxic, cytoprotective, or antioxidant cell responses were inferred by changes in lactate dehydrogenase (LDH) release, heme oxygenase-1 (HO-1) expression, or glutathione levels, respectively. Data showed that exposure of healthy LA-4 cells to organic carbon-rich DEP (25 microg/cm(2); 24 h) induced adaptive cytoprotective/antioxidant responses with no apparent cell injury. In contrast, exposure of inflamed LA-4 cells resulted in oxidative stress culminating in significant cytotoxicity. Exposure of healthy MTE cells to organic carbon-rich DEP (20 microg/cm(2); 24 h) was seemingly without effect, whereas exposure of inflamed MTE cells resulted in increased epithelial solute permeability. Thus, surface lung epithelial cells stressed by a state of inflammation and then exposed to organic carbon-rich DEP appear unable to respond to the additional oxidative stress, resulting in epithelial barrier dysfunction and injury. Adverse health outcomes associated with exposure to traffic-related air pollutants, like DEP, in patients with preexisting inflammatory respiratory diseases may be due, in part, to similar mechanisms.

A hyperlipidemic rabbit model provides new insights into pulmonary zinc exposure effects on cardiovascular health

This study ascertains the effects of zinc, a major component of particulate matter, on pulmonary and systemic endpoints using hyperlipidemic rabbits to model diet-induced human atherosclerosis. New Zealand White rabbits were fed a normal or cholesterol-enriched diet and then were intratracheally instilled 1x/week for 4 weeks with saline or 16 microg/kg of zinc, equal parts sulfate and oxide. Physiologic responses, blood after each exposure, and terminal bronchoalveolar lavage (BAL) were assessed. Rabbits fed a cholesterol-rich diet developed hyperlipidemia and had consistently higher circulating leukocyte counts than rabbits fed normal chow. Within minutes after zinc instillation, saturation of peripheral oxygen was decreased in hyperlipidemic rabbits and heart rate was increased in hyperlipidemic rabbits with total serum cholesterol levels greater than 200 mg/dl. Total circulating leukocytes levels were increased 24 h after the first zinc instillation, but upon repeated exposures this effect was attenuated. After repeated zinc exposures, BAL fluid (BALF) N-acetylglucosaminidase activity was increased regardless of hyperlipidemic state. Hyperlipidemic rabbits had an increase in BALF-oxidized glutathione and a decrease in serum nitrite. The study elucidates mechanisms by which the zinc metal component of PM drives cardiovascular health effects, as well as the possible susceptibility induced by hyperlipidemia. Furthermore, the study exemplifies the benefits of monitoring circulatory physiology during exposure as well as after exposure.

Molecular biomarkers of oxidative stress associated with bromate carcinogenicity

Potassium bromate (KBrO3) is a chemical oxidizing agent found in drinking water as a disinfection byproduct of surface water ozonation. Chronic exposures to KBrO3 cause renal cell tumors in rats, hamsters and mice and thyroid and testicular mesothelial tumors in rats. Experimental evidence indicates that bromate mediates toxicological effects via the induction of oxidative stress. To investigate the contribution of oxidative stress in KBrO3-induced cancer, male F344 rats were administered KBrO3 in their drinking water at multiple concentrations for 2-100 weeks. Gene expression analyses were performed on kidney, thyroid and mesothelial cell RNA. Families of mRNA transcripts differentially expressed with respect to bromate treatment included multiple cancer, cell death, ion transport and oxidative stress genes. Multiple glutathione metabolism genes were up-regulated in kidney following carcinogenic (400 mg/L) but not non-carcinogenic (20 mg/L) bromate exposures. 8-Oxodeoxyguanosine glycosylase (Ogg1) mRNA was up-regulated in response to bromate treatment in kidney but not thyroid. A dramatic decrease in global gene expression changes was observed following 1mg/L compared to 20 mg/L bromate exposures. In a separate study oxygen-18 (18O) labeled KBrO3 was administered to male rats by oral gavage and tissues were analyzed for 18O deposition. Tissue enrichment of 18O was observed at 5 and 24 h post-KBr18O3 exposure with the highest enrichment occurring in the liver followed by the kidney, thyroid and testes. The kidney dose response observed was biphasic showing similar statistical increases in 18O deposition between 0.25 and 50 mg/L (equivalent dose) KBr18O3 followed by a much greater increase above 50 mg/L. These results suggest that carcinogenic doses of potassium bromate require attainment of a threshold at which oxidation of tissues occurs and that gene expression profiles may be predictive of these physiological changes in renal homeostasis.

Acute ozone-induced differential gene expression profiles in rat lung

Ozone is an oxidant gas that can directly induce lung injury. Knowledge of the initial molecular events of the acute O3 response would be useful in developing biomarkers of exposure or response. Toward this goal, we exposed rats to toxic concentrations of O3 (2 and 5 ppm) for 2 hr and the molecular changes were assessed in lung tissue 2 hr postexposure using a rat cDNA expression array containing 588 characterized genes. Gene array analysis indicated differential expression in almost equal numbers of genes for the two exposure groups: 62 at 2 ppm and 57 at 5 ppm. Most of these genes were common to both exposure groups, suggesting common roles in the initial toxicity response. However, we also identified the induction of nine genes specific to 2-ppm (thyroid hormone-beta receptor c-erb-A-beta; and glutathione reductase) or 5-ppm exposure groups (c-jun, induced nitric oxide synthase, macrophage inflammatory protein-2, and heat shock protein 27). Injury markers in bronchoalveolar lavage fluid (BALF) were used to assess immediate toxicity and inflammation in rats similarly exposed. At 2 ppm, injury was marked by significant increases in BALF total protein, N-acetylglucosaminidase, and lavageable ciliated cells. Because infiltration of neutrophils was observed only at the higher 5 ppm concentration, the distinctive genes suggested a potential amplification role for inflammation in the gene profile. Although the specific gene interactions remain unclear, this is the first report indicating a dose-dependent direct and immediate induction of gene expression that may be separate from those genes involved in inflammation after acute O3 exposure.

Agonist-mediated airway challenge: cardiopulmonary interactions modulate gas exchange and recovery

Diverse agonists used for airway challenges produce a stereotypic sequence of immediate functional responses (e.g., bronchoconstriction, gas trapping, hypoxemia, etc.) at the time such reactions are triggered. The reaction incorporates both pulmonary and cardiac changes that clearly interact in an orchestrated fashion taking the subject (or animal model) through the response generally to ultimate recovery. We hypothesize that despite differences in the initiation of the response, diverse airway provocations lead to a cascade of events that converge through a common physiologic pathway. To better understand the sequence of events and the counterbalanced cardiopulmonary responses, we examined histamine, methacholine, and ovalbumin (OVA) challenges in the awake guinea pig model and assessed ventilatory and breathing mechanics in the context of associated cardiac parameters. With the histamine response as the prototype, we evaluated the role of beta-adrenoreceptors using propranolol (1.0-10 mg/kg i.p.) and found that beta-adrenoreceptors are critical in reducing challenge-induced gas trapping in the lungs. The disposition of the circulatory response to agonist challenge (the OVA model) was reflected in a significant absolute shunting of blood through poorly ventilated regions of the lung. The methacholine challenge revealed that gasping enhanced lung inflation and reversed the diminished Pa(O2). Moreover, beta-sympathetic function was critical to recovery. Collectively, the response profiles of these disparate models of airway challenge suggest a highly integrated balance to maintain gas exchange among the pulmonary airways and vasculature, modulated in recovery by beta-adrenoreceptors.

Antioxidant supplementation and nasal inflammatory responses among young asthmatics exposed to high levels of ozone

The inflammatory response to ozone in atopic asthma suggests that soluble mediators of inflammation are released in response to oxidant stress. Antioxidants may alleviate additional oxidative stress associated with photochemical oxidant pollution. This study investigates the impact of antioxidant supplementation on the nasal inflammatory response to ozone exposure in atopic asthmatic children. We conducted a randomized trial using a double-blinded design. Children with asthma (n = 117), residents of Mexico City, were given randomly a daily supplement of vitamins (50 mg/day of vitamin E and 250 mg/day of vitamin C) or placebo. Nasal lavages were performed three times during the 4-month follow-up and analysed for content of interleukin-6 (IL-6), IL-8, uric acid and glutathione (GSx). IL-6 levels in the nasal lavage were increased significantly in the placebo group after ozone exposure while no increase was observed in the supplement group. The difference in response to ozone exposure between the two groups was significant (P = 0.02). Results were similar for IL-8, but with no significant difference between the groups (P = 0.12). GSx decreased significantly in both groups. Uric acid decreased slightly in the placebo group. Our data suggest that vitamin C and E supplementation above the minimum dietary requirement in asthmatic children with a low intake of vitamin E might provide some protection against the nasal acute inflammatory response to ozone.

The lost intrauterine device: removal by hysterectomy

A case of migration of an intrauterine device (IUD) deep within the endometrium, presenting as heavy vaginal bleeding and abdominal pain, is discussed. The IUD had been in situ for 31 years. Standard retrieval techniques failed and removal necessitated hysterectomy. The complications of 'lost IUDs' are discussed and the need to enquire about removal in all women on approaching the menopause is emphasised.

Antioxidant supplementation and lung functions among children with asthma exposed to high levels of air pollutants

To evaluate whether acute effects of ozone, nitrogen dioxide, and particulates with mass median diameter less than 10 micro m could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial using a double-blinded design. Children with asthma (n = 158) who were residents of Mexico City were randomly given a daily supplement of vitamins (50 mg/day of vitamin E and 250 mg/day of vitamin C) or a placebo and were followed from October 1998 to April 2000. Pulmonary function tests were carried out twice a week in the morning. During the follow-up observation period, the mean 1-hour maximum ozone level was 102 ppb (SD = 47), and the mean 24-hour average PM(10) level was 56.7 micro g/m(3) (SD = 27.4). In children with moderate and severe asthma, ozone levels 1 day before spirometry were inversely associated significantly with forced expiratory flow (FEF(25-75)) (-13.32 ml/second/10 ppb; p = 0.000), FEV(1) (-4.59 ml/10 ppb; p = 0.036), and peak expiratory flow (PEF) (-15.01 ml/second/10 ppb; p = 0.04) in the placebo group after adjusting for potential confounding factors. No association between ozone and lung functions was observed in the supplement group. We observed significant differences in lung function decrements between groups for FEF(25-75) and PEF. Our results suggest that supplementation with antioxidants might modulate the impact of ozone exposure on the small airways of children with moderate to severe asthma.

Phylogenetic relationships within the eared seals (Otariidae: Carnivora): implications for the historical biogeography of the family

Phylogenetic relationships within the family Otariidae were investigated using two regions of the mitochondrial genome. A 360-bp region of the cytochrome b gene was employed for the primary phylogenetic analysis, while a 356-bp segment of the control region was used to enhance resolution of the terminal nodes. Traditional classification of the family into the subfamilies Arctocephalinae (fur seals) and Otariinae (sea lions) is not supported, with the fur seal Callorhinus ursinus having a basal relationship relative to the rest of the family. This is consistent with the fossil record which suggests that this genus diverged from the line leading to the remaining fur seals and sea lions about 6 million years ago (mya). There is also little evidence to support or refute the monophyly of sea lions. Four sea lion clades and five fur seal clades were observed, but relationships among these clades are unclear. Similar genetic divergences between the sea lion clades (D(a) = 0.054-0.078), as well as between the major Arctocephalus fur seal clades (D(a) = 0.040-0.069) suggest that these groups underwent periods of rapid radiation at about the time they diverged from each other. Rapid radiations of this type make the resolution of relationships between the resulting species difficult and indicate the requirement for additional molecular data from both nuclear and mitochondrial genes. The phylogenetic relationships within the family and the genetic distances among some taxa highlight inconsistencies in the current taxonomic classification of the family.

Oxidative interactions of synthetic lung epithelial lining fluid with metal-containing particulate matter

Epidemiology studies show association of morbidity and mortality with exposure to ambient air particulate matter (PM). Metals present in PM may catalyze oxidation of important lipids and proteins present in the lining of the respiratory tract. The present study investigated the PM-induced oxidation of human bronchoalveolar lavage (BAL) fluid (BALF) and synthetic lung epithelial lining fluid (sELF) through the measurement of oxygen incorporation and antioxidant depletion assays. Residual oil fly ash (ROFA), an emission source PM that contains approximately 10% by weight of soluble transition metals, was added (0-200 microg/ml) to BALF or sELF and exposed to 20% (18)O(2) (24 degrees C, 4 h). Oxygen incorporation was quantified as excess (18)O in the dried samples after incubation. BALF and diluted sELF yielded similar results. Oxygen incorporation was increased by ROFA addition and was enhanced by ascorbic acid (AA) and mixtures of AA and glutathione (GSH). AA depletion, but not depletion of GSH or uric acid, occurred in parallel with oxygen incorporation. AA became inhibitory to oxygen incorporation when it was present in high enough concentrations that it was not depleted by ROFA. Physiological and higher concentrations of catalase, superoxide dismutase, and glutathione peroxidase had no effect on oxygen incorporation. Both protein and lipid were found to be targets for oxygen incorporation; however, lipid appeared to be necessary for protein oxygen incorporation to occur. Based on these findings, we predict that ROFA would initiate significant oxidation of lung lining fluids after in vivo exposure and that AA, GSH, and lipid concentrations of these fluids are important determinants of this oxidation.

An 'injury-time integral' model for extrapolating from acute to chronic effects of phosgene

The present study compares acute and subchronic episodic exposures to phosgene to test the applicability of the 'concentrationxtime' (CxT) product as a measure of exposure dose, and to relate acute toxicity and adaptive responses to chronic toxicity. Rats (male Fischer 344) were exposed (six hours/day) to air or 0.1, 0.2, 0.5 and 1.0 ppm of phosgene one time or on a repeated regimen for up to 12 weeks as follows: 0.1 ppm (five days/week), 0.2 ppm (five days/week), 0.5 ppm (two days/week), or 1.0 ppm (one day/week) (note that the CxT for the three highest exposures was the same). Animals were sacrificed at 4, 8, and 12 weeks during the exposure and after four weeks recovery. Bronchoalveolar lavage (BAL) was performed 18 hours after the last exposure for each time period and the BAL supernatant assayed for protein. Elevated BAL fluid protein was defined as 'acute injury', diminished response after repeated exposure was defined as 'adaptation', and increased lung hydroxyproline or trichrome staining for collagen was defined as 'chronic injury'. Results indicated that exposures that cause maximal chronic injury involve high exposure concentrations and longer times between exposures, not high CxT products. A conceptual model is presented that explains the lack of CxT correlation by the fact that adaptation reduces an 'injury-time integral' as phosgene exposure is lengthened from acute to subchronic. At high exposure concentrations, the adaptive response appears to be overwhelmed, causing a continued injury-time integral, which appears to be related to appearance of chronic injury. The adaptive response is predicted to disappear if the time between exposures is lengthened, leading to a continued high injury-time integral and chronic injury. It has generally been assumed that long, continuous exposures of rodents is a conservative approach for detecting possible chronic effects. The present study suggests that such an approach my not be conservative, but might actually mask effects that could occur under intermittent exposure conditions.

The effect of a vitamin A acetate diet on ultraviolet radiation-induced immune suppression as measured by contact hypersensitivity in mice

The adverse health effects caused by increased exposure to ultraviolet radiation (UVR) due to deterioration of stratospheric ozone are of major concern. These health effects include sunburn, skin cancer, cataracts and immune suppression. Immune suppression has been associated with the release of cytokines, a defect in antigen presentation, induction of suppressor T cells and suppression of contact hypersensitivity (CH). CH is typically assessed by the mouse ear swelling test (MEST). Previous studies have demonstrated enhanced CH responses with vitamin A acetate (VAA) dietary supplementation assessed by MEST and the local lymph node assay (LLNA). To determine the effect that VAA has on UVR-induced immune suppression, we examined both the induction and elicitation phases of CH using murine models. The MEST was used to evaluate the interaction of UVR and VAA on CH elicitation. However, a positive MEST response requires that the induction phase as well as the elicitation phase of CH be functional. The LLNA was used to evaluate the interaction of UVR and VAA only on CH induction. We tested the hypothesis that mice maintained on a VAA-enriched diet are more resistant to UVR-induced immune suppression (CH) than those maintained on a control diet. Mice were maintained on a VAA-enriched or the control diet for 3 weeks and then exposed to UVR 3 days prior to sensitization with 2,4-dinitrofluorobenzene (DNFB). VAA enhanced the MEST response in both UVR-exposed and non-UVR-exposed mice. The VAA-enriched diet did not significantly alter the LLNA response in either UVR- or non-UVR-exposed mice. However, there was significant suppression in CH by UVR as measured by the LLNA. These results indicate that (1) the VAA-enriched diet does not restore the number of proliferating cells in the CH induction phase of UVR-induced immunosuppression; (2) the immunosuppressive effects of UVR affect the induction phase of CH; and (3) the LLNA should be examined as an alternative to the MEST for measurement of UVR-induced immunosuppression. The data indicate that the VAA-enriched diet enhanced the elicitation response (MEST) but not the earlier induction phase (LLNA). Further studies are necessary to define mechanisms of action, but modulation of cytokines and effects of specific lymphocyte subsets, as well as systemic effects and local modulation at the site of elicitation are possible. Additionally, future studies to evaluate the effect of the VAA-enriched diet when multiple doses of both UVR and DNFB are used would be of interest for both the LLNA and MEST end-points.

Plasmodium vivax synonymous substitution frequencies, evolution and population structure deduced from diversity in AMA 1 and MSP 1 genes

Polymorphic regions of the genes encoding Plasmodium vivax apical membrane antigen 1 (PvAMA1) and P. vivax merozoite surface protein 1 (PvMSP1) were sequenced to examine population diversity both within and between geographical areas. Sequences were obtained for 219 isolates for PvAMA1 and for 175 isolates for PvMSP1 from Africa, China, India, Indonesia, Philippines, Papua New Guinea, Solomon Islands and Thailand. Over half of the isolates were obtained from different regions within the Philippines, and this was used to look at the diversity within a country. Sixty nine haplotypes and 22 polymorphic sites in a 414-bp region of PvAMA1 and 41 haplotypes and 34 polymorphic sites in a 249-bp fragment of PvMSP1 were detected. For both PvAMA1 and PvMSP1, four previously unreported polymorphic nucleotide positions were identified. Population analysis indicated that there were significant differences in allele frequencies between different regions but these differences were small compared to the diversity within populations (Fixation index, F(ST), of 0.126 and 0.078 for PvAMA1 and PvMSP1, respectively). PvAMA1 and PvMSP1 had similar nonsynonymous substitution frequencies but surprisingly, the synonymous substitution frequency for PvMSP1 was eight times the frequency for PvAMA1 suggesting that synonymous substitutions in at least PvAMA1 are not neutral.

Oxidative stress in female B6C3F1 mice following acute and subchronic exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a highly persistent trace environmental contaminant and is one of the most potent toxicants known to man. Hassoun et al. (1998, Toxicol. Sci. 42, 23-27) reported an increase in the production of reactive oxygen species (ROS) in the brain of female B6C3F1 mice following subchronic exposure to TCDD at doses as low as 0.45 ng/kg/day. In the present study, oxidative stress was characterized in liver, spleen, lung, and kidney following subchronic (0.15-150 ng/kg; 5 days/week for 13 weeks, po) or acute exposure (0.001-100 microg/kg, po) to TCDD in order to investigate the interaction between tissue concentration and time for production of ROS. Seven days following acute administration of TCDD, mice were sacrificed; they demonstrated increases in liver superoxide anion production (SOAP) and thiobarbituric acid reactive substances (TBARS) at doses of 10 and 100 microg/kg, associated with hepatic TCDD concentrations of 55 and 321 ng/g, respectively. Liver obtained from mice following subchronic TCDD exposure demonstrated an increase in SOAP and TBARS above controls at doses of 150 ng/kg/day with liver TCDD concentration of only 12 ng/g. Interestingly, glutathione (GSH) levels in lung and kidney following sub-chronic TCDD exposure were decreased at the low dose of 0.15 ng/kg/day. This effect disappeared at higher TCDD doses. The data suggest that higher tissue TCDD concentrations are required to elicit oxidative stress following acute dosing than with subchronic TCDD exposure. Therefore, the mechanism of ROS production following TCDD exposure does not appear to be solely dependent upon the concentration of TCDD within the tissue. In addition, very low doses of TCDD that result in tissue concentrations similar to the background levels found in the human population produced an effect on an oxidative stress endogenous defense system. The role of this effect in TCDD-mediated toxicity is not known and warrants further investigation.

Postsealing genetic variation and population structure of two species of fur seal (Arctocephalus gazella and A. tropicalis)

Commercial sealing in the 18th and 19th centuries had a major impact on the Antarctic and subantarctic fur seal populations (Arctocephalus gazella and A. tropicalis) in the Southern Ocean. The intensive and unrestricted nature of the industry ensured substantial reductions in population sizes and resulted in both species becoming locally extinct at some sites. However, both species are continuing to recover, through the recolonization of islands across their former range and increasing population size. This study investigated the extent and pattern of genetic variation in each species to examine the hypothesis that higher levels of historic sealing in A. gazella have resulted in a greater loss of genetic variability and population structure compared with A. tropicalis. A 316-bp section of the mitochondrial control region was sequenced and revealed nucleotide diversities of 3.2% and 4.8% for A. gazella and A. tropicalis, respectively. There was no geographical distribution of lineages observed within either species, although the respective PhiST values of 0.074 and 0.19 were significantly greater than zero. These data indicate low levels of population structure in A. gazella and relatively high levels in A. tropicalis. Additional samples screened with restriction endonucleases were incorporated, and the distribution of restriction fragment length polymorphism (RFLP) and sequence haplotypes were examined to identify the main source populations of newly recolonized islands. For A. tropicalis, the data suggest that Macquarie Island and Iles Crozet were probably recolonized by females from Marion Island, and to a lesser extent Ile Amsterdam. Although there was less population structure within A. gazella, there were two geographical regions identified: a western region containing the populations of South Georgia and Bouvetoya, which were the probable sources for populations at Marion, the South Shetland and Heard Islands; and an eastern region containing the panmictic populations of Iles Kerguelen and Macquarie Island. The latter region may be a result of a pronounced founder effect, or represent a remnant population that survived sealing at Iles Kerguelen.

Dietary restriction mitigates ozone-induced lung inflammation in rats: a role for endogenous antioxidants

Studies were undertaken to determine whether dietary restriction protects against acute pulmonary oxidant challenge. Male F344 rats were fed NIH-31 diet either ad libitum or at restricted levels equal to 75% that of ad libitum intake. After 3 wk of dietary adaptation, animals were exposed by inhalation to 2.0 ppm ozone (O3) for 2 h or chamber air and evaluated for cellular and biochemical indices of pulmonary toxicity. Compared to air controls, bronchoalveolar lavage fluid (BALF) from O3 exposed ad libitum fed rats contained increased protein (145 versus 380 microg/ml), PMN infiltration (0 versus 11%) and fibronectin (45 versus 607 U/ml). Diet restriction abrogated these indicators of pulmonary inflammation induced by ozone. Binding of 18O3 to BALF protein and cells was significantly decreased in diet restricted rats while BALF ascorbate and glutathione levels, but not alpha-tocopherol or urate, were elevated compared to ad libitum fed rats. Taken together, these results indicate that dietary restriction affords protection against O3-induced oxidant toxicity. Protection is mediated partially by increases in ascorbate in the fluid bathing the lung surface, thereby providing an antioxidant sink which minimizes the ability of O3 to reach biological targets.

Mouse strain differences in ozone dosimetry and body temperature changes

Strain differences in susceptibility to inhaled ozone (O3) have been observed in mice, with C57BL/6J (B6) mice reported to be more sensitive than C3H/HEJ (C3) mice when exposed to equal concentrations of O3. To determine whether differences in the delivered dose of O3 to the lung could help explain these differences, C3 and B6 mice were exposed to 18O-labeled ozone (18O3), and the resulting 18O concentrations in pulmonary tissues were monitored as an indicator of O3 delivered dose. Body core temperatures (Tco) of similarly treated mice were measured during O3 exposures (using surgically implanted temperature probes) in an effort to correlate lung O3 dose to changes in basal metabolism. Immediately after exposure to 18O3, C3 mice had 46% less 18O (per mg dry wt) in lungs and 61% less in tracheas than B6 mice. Nasal 18O tended to be lower in the C3 mice, but these differences were not significant. Although both strains responded to the O3 exposure with significant decreases in Tco, C3 mice had a 70% greater mean temperature x time product decrease during the exposure than B6 mice. These results suggest that the strain differences in O3 susceptibility may be due to differences in O3 dose to the lung, which may be related to differences in the ability of the mice to lower their Tco in response to O3 exposure.

Antioxidants in bronchoalveolar lavage fluid cells isolated from ozone--exposed normal and ascorbate-deficient guinea pigs

Previous studies have indicated that systemic deficiency in one of the critical antioxidants, ascorbate, does not significantly exacerbate ozone-induced lung injury and changes in lung antioxidants following longer-term exposure. Because alveolar cells encounter the highest ozone dose upon exposure and lack direct blood supply, systemic ascorbate deficiency may exacerbate ozone response on antioxidants within these cells. Female Hartley guinea pigs (30 days old) were fed either a regular guinea pig chow or chow that lacked ascorbate. The dietary regimen was started 1 week prior to exposure, continued through ozone exposure (0, 0.2, 0.4, or 0.8 ppm, 23 h/day, 1 week), and during 1 week recovery in clean air following exposure. Immediately after 1 week of exposure or recovery, lungs were lavaged and cells were counted in bronchoalveolar lavage fluid (BALF). Protein, ascorbate, uric acid, total glutathione (GSH), and alpha-tocopherol were analyzed in these cells. Ozone caused an increase in total BALF cells and total cellular protein after 0.4 and 0.8 ppm ozone. The increase was more pronounced in ascorbate-deficient guinea pigs. Protein per million cells, however, was not changed by ozone or diet. In ascorbate-sufficient guinea pigs, ascorbate levels were increased only after 0.2 ppm ozone. However, uric acid (at 0.4 and 0.8 ppm ozone) and GSH (at all concentrations of ozone) levels were increased in both dietary groups. Ascorbate deficiency did not affect basal uric acid or GSH levels in BALF cells. There was a small diet-related depletion in cellular alpha-tocopherol. Ozone exposure also decreased alpha-tocopherol regardless of diet. The above changes except for alpha-tocopherol appeared to be reversed after 1 week of recovery in both dietary groups. In summary, ozone is capable of inducing a mechanism that increases antioxidants such as ascorbate, GSH, and uric acid. GSH and uric acid are not affected by ascorbate deficiency, but alpha-tocopherol is depleted. GSH and uric acid may be critical in ozone-induced adaptation during ascorbate deficiency.

Ozone toxicity in the mouse: comparison and modeling of responses in susceptible and resistant strains

Previous studies from this laboratory have demonstrated a concentration-related hypothermia and increases in bronchoalveolar lavage (BAL) fluid indexes of toxicity in the rat after exposure to environmentally relevant levels of ozone (O3). In similar studies with C57BL/6J (B6) and C3H/HeJ (C3) mice, other investigators have reported differential effects on BAL toxicity indexes between the two strains after O3 exposure. The present study investigated the relationship between the reported strain differences in BAL parameters in B6 and C3 mice exposed to O3 and the induced hypothermic response. Male 80-day-old mice (n = 94, 47/strain) were used for these studies. Subsets (n = 8/strain) of these animals were surgically implanted with radiotelemetry transmitters that permitted continuous monitoring of core body temperature and activity. All telemetry animals and an equal number of nontelemetry animals (n = 8/strain) were exposed to filtered air for 24 h followed by a 2-h exposure to 2 parts/million 16O3. With use of a similar protocol, groups of nontelemetry mice (n = 12/strain) were exposed to either filtered air or 2 parts/million 16O3 for 2 h. At 0 or 22 h postexposure, mice were anesthetized with halothane and intubated, and their lungs were lavaged with 37 degrees C saline. Although both strains of mice exhibited significant abrupt decreases in core body temperature on exposure to O3 and both recovered rapidly after cessation of the O3 exposure, the response of the C3 mice was more dynamic than that of the B6 mice. Similarly, both strains showed characteristic changes in biomarkers of O3 toxicity; however, the increases in BAL fluid protein and cells at 22 h postexposure were significantly greater and the percentage of neutrophils was significantly less in B6 mice than in C3 mice. It is possible that the strain differences in BAL constituents may be related to the differences in the hypothermic response.

Ozone dose and effect in humans and rats. A comparison using oxygen-18 labeling and bronchoalveolar lavage

In an effort to improve risk assessments for ozone (O3) we compared the incorporation of inhaled oxygen-18-labeled O3 (18O3) into the lungs of humans and laboratory rats. Cells and fluids obtainable through bronchoalveolar lavage (BAL) were examined after exposure to 18O3 to determine whether excess 18O concentrations (presumed to be reaction products of 18O3) could be detected and equated to the O3 dose to the lung. Three O3 effect measurements (increased BAL protein and neutrophils and decreased BAL macrophages) were also made in subjects or animals exposed in parallel to determine whether there was a correspondence between dose and effect measurements. Eight human male volunteers 18 to 35 yr of age were exposed to 18O3 (0.4 ppm for 2 h) with 15-min alternating periods of heavy treadmill exercise and rest. Rats (F344) were exposed identically, except without exercise. 18O3 was generated directly from pure 18O2. BAL cells and centrifugally separable surfactant material were freeze-dried and analyzed by mass spectrometer for excess 18O. Results showed that the exercising humans had four- to fivefold higher 18O concentrations in all of their BAL constituents than did the rats. The humans also had significant increases in all of the effects markers after 0.4 ppm O3, whereas the rats did not. Rats that were exposed to higher concentrations of 18O3 (2.0 ppm) had levels of 18O in BAL that were more comparable to but still lower than those of exercising humans. Changes in all of the effects markers in these rats were comparable or higher than in exercising humans.(ABSTRACT TRUNCATED AT 250 WORDS)

Large loop excision of the transformation zone (LLETZ) as an alternative to both local ablative and cone biopsy treatment: a series of 1000 patients

One thousand patients, referred to the Oxford Colposcopy Clinic, were treated with either large loop excision of the transformation zone (LLETZ, 891 cases) or LLETZ cone (109 cases). Forty-five LLETZ cones were performed empirically, 64 under microcolposcopic guidance. Over 98% of patients were managed as outpatients under local anaesthesia, and 87% of new patients treated with LLETZ had treatment at their first visit. Ninety percent of patients had at least cervical intraepithelial neoplasia grade one (CIN I) and 73% had CIN II or worse. Seventeen cases of invasive or possibly invasive disease were detected, 6 of them unsuspected. The overall rate of complete excision of CIN or worse was 72%. Follow-up was cytologic with or without colposcopy depending on lesion severity. Ninety-one percent of 967 treated patients were free of dyskaryosis at a mean follow-up of 23 months, with complete excision of CIN or worse at LLETZ a significant predictive factor. No cases of invasive carcinoma have developed following treatment. Major morbidity was uncommon, with 3.8% severe hemorrhage. Stenosis was noted in 3.8% cases, mostly after LLETZ cone. One patient (0.1%) has reduced fertility possibly attributable to LLETZ. Questionnaire assessment revealed a very high degree of acceptability of the treatment to patients. LLETZ and LLETZ cone have proved highly acceptable and effective outpatient diagnostic and treatment alternatives to both local ablation and cone biopsy in the Oxford Colposcopy Clinic.

Comparison of antioxidant substances in bronchoalveolar lavage cells and fluid from humans, guinea pigs, and rats

Antioxidants located in the lining layer of the respiratory tract may be important in determining sensitivity of lung tissues to inhaled pollutants. This study addressed species differences in the amounts of ascorbic acid (AH2), glutathione (GSH), uric acid (UA), and alpha-tocopherol (AT) in bronchoalveolar lavage (BAL) fluid and cells of humans, guinea pigs, and rats. Protein and lipid phosphorus (lipid P) were used as normalizing factors. More than 90% of the lavageable AH2, UA, GSH, protein, and lipid P was present in the extracellular fraction of BAL in rats and guinea pigs, while over 95% of the lavageable AT was located in the BAL cells. BAL fluid AH2/protein in rats was 7- to 9-fold higher than in humans and guinea pigs. However, human BAL fluid had 2- to 8-fold higher UA/protein, GSH/protein, and AT/protein ratios than rats and guinea pigs. In BAL cells, rats had higher AH2/protein and AT/protein ratios than guinea pigs and humans, and both rats and guinea pigs had higher GSH and AT/protein ratios than humans. Individual variability among humans in the BAL fluid and cellular antioxidants was generally greater than in the laboratory animals. These data demonstrate that some large species differences exist in BAL fluid and cellular antioxidants which could affect susceptibility to oxidant pollutants.

Application of the EPR spin-trapping technique to the detection of radicals produced in vivo during inhalation exposure of rats to ozone

Ozone is known to induce lipid peroxidation of lung tissue, although no direct evidence of free radical formation has been reported. We have used the electron paramagnetic resonance (EPR) spin-trapping technique to search for free radicals produced in vivo by ozone exposure. The spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) was administered ip to male Sprague-Dawley rats. The rats were then exposed for 2 hr to either 0, 0.5, 1.0, 1.5, or 2.0 ppm ozone with 8% CO2 to increase their respiratory rate. A six-line 4-POBN/radical spin adduct signal (aN = 15.02 G and a beta H = 3.27 G) was detected by EPR spectroscopy in lipid extracts from lungs of rats treated with 4-POBN and then exposed to ozone. Only a weak signal was observed in the corresponding solution from rats exposed to 0 ppm ozone (air with CO2 only). The concentration of the radical adduct increased as a function of ozone concentration. After administration of 4-POBN, rats were exposed for either 0.5, 1.0, 2.0, or 4.0 hr to either 0 or 2.0 ppm ozone (with CO2). The radical adduct concentration of the ozone-exposed groups at exposure times of 2.0 and 4.0 hr was significantly different from that of the corresponding air control groups. A correlation was observed between the radical adduct concentration and the lung weight/body weight ratio. These results demonstrate that ozone induces the production of free radicals in rat lungs during inhalation exposure and that radical production may be involved in the induction of pulmonary toxicity by ozone. This is the first direct evidence for ozone-induced free radical production in vivo.

Gastrointestinal malignancies as a complication of chronic myeloid leukaemia

A 70-year-old patient is presented who, after chemotherapy for chronic myeloid leukaemia, developed two separate gastrointestinal malignancies. His family history indicated a strong family tendency towards neoplasia, and it is speculated that this predisposition may have been potentiated by the chemotherapy or the leukaemic process itself. It is stressed that, in such cases of multiple malignancy, each condition should be treated on its own merits.

Incorporation and disappearance of oxygen-18 in lung from mice exposed to 1 ppm 18O3

In this study, 18O3 was used as a tracer for inhaled ozone in mice. The amount of ozone-derived oxygen (ODO) in the lungs was determined by measuring the amount of oxygen-18 in excess of the natural abundance level which remained covalently bound to organic constituents of lung following exposure to 1 ppm 18O3 for less than or equal to 60 min. The rate of disappearance of ODO from the lungs was determined by quantifying the rate of decrease of oxygen-18 in excess of the natural abundance level in lung from mice exposed to 1 ppm 18O3 for 45 min. With exposure to 1 ppm 18O3. ODO accumulated in lung at a rate of 4.38 pmol/mg dry weight/min. Ozone-derived oxygen had a half-life in lung of approximately 6 hr. We estimate that a minimum of 44 pmol of O3 reacted with lung every minute of exposure to 1 ppm O3.

Agranulocytosis caused by dapsone therapy for granuloma annulare

Dapsone has been suggested as a useful drug in the treatment of granuloma annulare; however, adverse reactions include a potentially life-threatening agranulocytosis. We report the case of a 50-year-old woman in whom agranulocytosis and septicemia developed after 7 weeks of therapy with dapsone for granuloma annulare. Full recovery followed cessation of this drug, but caution is advised in prescribing dapsone for relatively benign skin conditions.

Detection of CCl4-induced oxidation of hepatic tissue in vivo by oxygen-18 tracing

Oxidation of rat hepatic tissue was measured as incorporation of oxygen-18 (18O) from 18O2 following exposure to carbon tetrachloride (CCl4). Anesthetized rats were injected with CCl4 and allowed to breathe 18O2 for 1 hr, and then livers were homogenized, fractionated, and dried. The dried fractions were pyrolyzed to CO by an oxygen elemental analyzer, the CO was oxidized to CO2, and isotope ratio mass spectrometry was used to determine the abundance of 18O in the CO2. Rats that breathed 18O2 (21% in N2) for 1 hr had significant incorporation of 18O into lipids, solutes, and macromolecules of the liver. Injection with CCl4 increased incorporation of 18O into all liver fractions, although this increase was significant only in the lipid fraction. Rats pretreated with phenobarbital and then given CCl4 had significantly increased 18O in all liver fractions although it was greatest in the lipid fraction. About 5 mumol of 18O per gram of dry liver was incorporated in phenobarbital/CCl4-treated rats, of which 60% was in the water-soluble fraction, 17% in the lipids, and 16% in the macromolecules. Piperonyl butoxide administration abolished the CCl4-induced 18O incorporation. Thus, 18O incorporation appeared to provide a measure of oxidation in all tissue fractions following in vivo CCl4-induced liver injury.