Organochlorine pesticides, polychlorinated biphenyls, and butyltin compounds in blubber and livers of stranded California sea lions, elephant seals, and harbor seals from coastal California, USA

Concentrations of polychlorinated biphenyls (PCBs), DDTs (p,p'-DDE, p,p'-DDD, p,p'-DDT), chlordanes (CHLs; cis-chlordane, cis-nonachlor, trans-nonachlor, and oxychlordane), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), tris(4-chlorophenyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMOH), and mono- (MBT), di-(DBT), and tri-butyltin (TBT) were determined in blubber and livers of 15 California sea lions (Zalophus californianus), 6 northern elephant seals (Mirounga augustirostris), and 10 harbor seals (Phoca vitulina) found stranded along the coasts of California, USA, during 1991-1997. Among the organochlorines analyzed, DDTs were predominant, followed in decreasing order by PCBs, CHLs, TCPMe, TCPMOH, HCHs, and HCB. The greatest concentrations of organochlorines were found in California sea lions. The highest DDT and PCB concentrations found in the blubber of California sea lions were 2,900 and 1,300 microg/g, lipid weight, respectively. Concentrations of TCPMe and TCPMOH in California sea lions were correlated significantly with DDT concentrations. Concentration ratios of various organochlorines in harbor seal livers were different from those in California sea lions and elephant seals, which suggested that the sources of exposure of harbor seals to organochlorines were different from those in the other two species. Concentrations of butyltin compounds in livers of pinniped species ranged from 2 to 99 ng/g, wet weight, which were less than those observed in cetaceans and in California sea otters.

The evolution of climate over the last millennium

Knowledge of past climate variability is crucial for understanding and modeling current and future climate trends. This article reviews present knowledge of changes in temperatures and two major circulation features-El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO)-over much of the last 1000 years, mainly on the basis of high-resolution paleoclimate records. Average temperatures during the last three decades were likely the warmest of the last millennium, about 0.2 degrees C warmer than during warm periods in the 11th and 12th centuries. The 20th century experienced the strongest warming trend of the millennium (about 0.6 degrees C per century). Some recent changes in ENSO may have been unique since 1800, whereas the recent trend to more positive NAO values may have occurred several times since 1500. Uncertainties will only be reduced through more extensive spatial sampling of diverse proxy climatic records.

Accumulation of perfluorooctane sulfonate in marine mammals

Perfluorooctane sulfonate (PFOS) is a perfluorinated molecule that has recently been identified in the sera of nonindustrially exposed humans. In this study, 247 tissue samples from 15 species of marine mammals collected from Florida, California, and Alaskan coastal waters; and northern Baltic Sea; the Arctic (Spitsbergen); and Sable Island in Canada were analyzed for PFOS. PFOS was detected in liver and blood of marine mammals from most locations including those from Arctic waters. The greatest concentrations of PFOS found in liver and blood were 1520 ng/g wet wt in a bottlenose dolphin from Sarasota Bay, FL, and 475 ng/mL in a ringed seal from the northern Baltic Sea (Bothnian Sea), respectively. No age-dependent increase in PFOS concentrations in marine mammals was observed in the samples analyzed. The occurrence of PFOS in marine mammals from the Arctic waters suggests widespread global distribution of PFOS including remote locations.

Climate variability 50,000 years ago in mid-latitude Chile as reconstructed from tree rings

High-resolution proxies of past climate are essential for a better understanding of the climate system. Tree rings are routinely used to reconstruct Holocene climate variations at high temporal resolution, but only rarely have they offered insight into climate variability during earlier periods. Fitzroya cupressoides-a South American conifer which attains ages up to 3,600 years-has been shown to record summer temperatures in northern Patagonia during the past few millennia. Here we report a floating 1,229-year chronology developed from subfossil stumps of F. cupressoides in southern Chile that dates back to approximately 50,000 14C years before present. We use this chronology to calculate the spectral characteristics of climate variability in this time, which was probably an interstadial (relatively warm) period. Growth oscillations at periods of 150-250, 87-94, 45.5, 24.1, 17.8, 9.3 and 2.7-5.3 years are identified in the annual subfossil record. A comparison with the power spectra of chronologies derived from living F. cupressoides trees shows strong similarities with the 50,000-year-old chronology, indicating that similar growth forcing factors operated in this glacial interstadial phase as in the current interglacial conditions.

Accumulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin by rainbow trout (Onchorhynchus mykiss) at environmentally relevant dietary concentrations

Rainbow trout were fed a diet containing 1.8, 18, or 90 pg/g 3H-2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for up to 320 d. Concentrations of TCDD were determined in muscle, liver, and ovaries at 100, 150, 200, and 250 d. Concentrations of TCDD reached an apparent steady-state concentration in liver after 100 d of exposure, whereas concentrations in other tissues continued to increase until 150 d of exposure. The greatest portion of the total mass of TCDD was present in the muscle tissue with lesser proportions in other organs. As the ovaries developed before spawning, an increase occurred in the total mass of TCDD present in this tissue. The assimilation rate of TCDD during the initial 100 d of the exposure was determined to be between 10 and 30%. This is somewhat less than estimates derived based on both uptake and elimination constants determined during shorter exposures. Biomagnification factors (BMFs) were estimated for all tissues and exposure concentrations, and at all exposure periods. Lipid-normalized BMFs for muscle ranged from 0.38 to 1.51, which is consistent with the value of 1.0 predicted from fugacity theory. Uptake and depuration rate constants were determined and used to predict individual organ TCDD concentrations. Comparison with observed values indicated that the model could be used to predict tissue concentrations from the known concentrations of TCDD in food. This model will allow more refined risk assessments by predicting TCDD concentrations in sensitive tissues such as developing eggs.

Pathologic alterations in adult rainbow trout, Oncorhynchus mykiss, exposed to dietary 2,3,7,8-tetrachlorodibenzo-p-dioxin

Adult female rainbow trout (Oncorhynchus mykiss) fed [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) impregnated diet at 0, 1.8, 18 or 90 ng/kg food for up to 320 days were evaluated by clinical pathology, gross pathology and histopathology procedures. Gross pathological changes were limited to a slight increase in the incidence of lesions of the caudal fins in the treated groups. Mixed mononuclear inflammatory infiltrates were present in multiple organs of fish from control and treatment groups, but did not appear to be treatment related. Lesions associated with exposure to TCDD were observed histologically in liver and spleen after 100 and 250+ days of exposure. The livers of TCDD-treated fish contained less hepatocellular glycogen, more mitotic figures, greater anisokaryosis, anisocytosis, nuclear chromatin clumping and margination. Prominent nucleoli were directly proportional to TCDD dose. Hepatocellular changes in fish exposed to TCDD also included single cell necrosis and clear cytoplasmic vacuoles consistent with lipid. Some fish from all TCD exposed groups had lower lymphoid density compared to controls at all time intervals. Fish exposed to the highest TCDD dose had decreased peripheral leukocyte counts after 50 and 100 days. The lowest observable adverse effect level (LOAEL) for these effects was 5.69 ngTCDD/kg in diet and 0.90 ng TCDD/kg liver.

The prevalence of asthma appears to be inversely related to the incidence of typhoid and tuberculosis: hypothesis to explain the variation in asthma prevalence around the world

The prevalence of asthma varies widely throughout the world. We now believe that asthma is due to airway inflammation caused by an imbalance of the T-lymphocytes in the airway. The atopy that drives asthma is due to a predominance of Th2 lymphocytes in the airway. This paper links the prevalence of asthma inversely to the prevalence of tuberculosis and enteric infection. We will argue that the reason we observe such marked variations in the prevalence of asthma around the world is the fact that in the developing world there is a survival advantage in the fetal immune response to mature from Th2 to Th1 lymphocyte predominant. A Th1 response is required to combat infectious diseases such as typhoid and tuberculosis. Data from the World Health Organization confirms that these two infectious diseases occur very rarely in those communities where the asthma is high. It may be that the clean and infection-free environment of Australia and New Zealand is responsible for the region of Oceania having the dubious honor of having the highest prevalence of asthma in the world.

Dioxin-like and non-dioxin-like toxic effects of polychlorinated biphenyls (PCBs): implications for risk assessment

Polychlorinated biphenyls (PCBs) are persistent, bioaccumulative and toxic contaminants in the environment. Individual PCB congeners exhibit different physico-chemical properties and biological activities which result in different environmental distributions and toxicity profiles. The variable composition of PCB residues in environmental matrices and their different mechanisms of toxicity, complicate the development of scientifically based regulations for the risk assessment. Various approaches for the assessment of risks of PCBs have been critically examined. Recent developments in the toxic equivalency factor (TEF) approach for the assessment of toxic effects due to dioxin-like PCBs have been examined. PCB exposure studies which describe non-dioxin-like toxic effects, particularly neuro-behavioral effects and their effective doses in animals were also considered. A comparative assessment of effective doses for dioxin-like and non-dioxin-like effects by PCBs was made to evaluate the relative significance of non-ortho and ortho-substituted PCBs in risk assessment. Using mink as an example, relative merits and implications of using TEF and total PCB approaches for assessing the potential for toxic effects in wildlife was examined.

A 7-year review of deaths on the general paediatric wards at John Hunter Children's Hospital, 1991-97

OBJECTIVE

To study the palliative management of children dying on the wards of a tertiary referral centre. In particular to identify areas of difficulty and discuss ways in which these can be improved.

METHODOLOGY

All children between the ages 1 and 19 years dying on the general paediatric wards of the John Hunter Children's Hospital (JHCH) (a tertiary referral centre in New South Wales Hunter Valley) between 1991 and 1998 were included in the study. The main outcome measures were the duration of 'terminal care only' treatment; time spent in hospital in the previous year; analgesia used, dose and route of administration; adjuvant medications; quality of life in the final 24 h.

RESULTS

Eighteen children (aged between 1 and 19 years) died on the general paediatric wards at JHCH between 1991 and 1998. The most common diagnosis was malignancy (five patients), with cystic fibrosis, cerebral palsy and a degenerative neurological disorder each accounting for four patients, and one child had herpes simplex encephalitis. In all children the terminal nature of their condition was recognized and in all but three patients there was documentation of 'not for resuscitation' (NFR) orders following discussion with the child's parents. The mainstay of analgesia was an intravenous narcotic infusion with 11 (61%) children needing a morphine infusion. Fifteen patients (83%) required other medications including antiemetics, anticonvulsants and corticosteroids. Twelve (66%) children were semiconscious or unconscious on the day of death. Three children were uncomfortable and distressed, one alert and symptom free and in two cases the level of consciousness was not recorded. Three children continued to have seizures until their death.

CONCLUSION

The majority of terminally ill children were managed well with intravenous narcotics and adjuvant medications. There may be scope for such children to be managed successfully at home with appropriate support for the general practitioner by paediatric and palliative care specialists. Some cases in which palliation is difficult do remain in hospital and additional measures need to be employed to ensure a symptom free death for these children.

Interpreting differential temperature trends at the surface and in the lower troposphere

Estimated global-scale temperature trends at Earth's surface (as recorded by thermometers) and in the lower troposphere (as monitored by satellites) diverge by up to 0.14 degrees C per decade over the period 1979 to 1998. Accounting for differences in the spatial coverage of satellite and surface measurements reduces this differential, but still leaves a statistically significant residual of roughly 0.1 degrees C per decade. Natural internal climate variability alone, as simulated in three state-of-the-art coupled atmosphere-ocean models, cannot completely explain this residual trend difference. A model forced by a combination of anthropogenic factors and volcanic aerosols yields surface-troposphere temperature trend differences closest to those observed.

Chemotherapy reduces the prevalence of asthma symptoms in children with cancer: implications for the role of airway inflammation in asthma

OBJECTIVE

Asthma is common in Australian children, with a prevalence of 30%. Airway inflammation is an important determinant of asthma symptoms. Chemotherapy used for the treatment of many childhood cancers suppresses inflammation. The prevalence of asthma symptoms in children treated with chemotherapy is unknown.

METHODOLOGY

We therefore performed a survey of symptoms of asthma in children attending the oncology clinic at John Hunter Children's Hospital during the first 6 months of 1996.

RESULTS

Fifty children aged 1-17 years were surveyed. Thirty-two of the children were in remission and had completed treatment with chemotherapy and 18 were currently undergoing treatment with chemotherapy. There was no significant difference in the prevalence of asthma in children before, during and after chemotherapy (26%, 22% and 34%), or in the prevalence of asthma in their siblings (28%). No child was classified as having persistent asthma while on chemotherapy and there was a significant reduction in the requirement for preventive asthma drugs 12% versus 0% (P = 0.03) being reported during chemotherapy.

CONCLUSION

The prevalence of asthma in children who develop cancer is similar to their siblings and the same as the population as a whole. While asthma symptoms do not disappear completely during chemotherapy, the severity of asthma symptoms is less, with no need for asthma preventive treatment. The immunosuppressive side effects of the chemotherapy used in the treatment of childhood cancer appear to induce a remission in asthma symptoms. The ongoing requirement for bronchodilator therapy in patients whilst on chemotherapy suggests airway hyperreactivity persists in children while they are on chemotherapy. Prospective study of the airways of this group of patients promises to provide insights into the relationships between airway hyperreactivity, airway inflammation and asthma.

Suspected infection in children with cancer

The microbiology and severity of suspected infections in children with cancer admitted to the John Hunter Children's Hospital was determined in order to assess whether any alteration to the infection treatment protocol was required. All children with cancer aged 1-17 years who had an episode of suspected or proven infection that required parenteral treatment at John Hunter Children's Hospital (JHCH) during 1994/95 were reviewed. Thirty-seven children were treated for cancer at JHCH; 62 admissions for suspected infection which involved 26 children were reviewed. Sixteen of these children had a permanent central line. Children with a central line had an increase in the number of days of inpatient treatment required for the treatment of suspected infection, and they had more episodes of infection. A pathogen was isolated more frequently with blood cultures being positive more often and gram-positive species were methicillin resistant more often. These differences were not statistically significant. A pathogen was isolated in 52% of admissions. Sixteen pathogens were gram positive; 12 were gram negative, two were fungal and two were viral. Blood cultures were positive in 21 of 62 admissions, skin swabs in four admissions, urine cultures in three admissions, stool in two admissions and one species was isolated from an epidural catheter tip and from the sputum. In 16% of admissions, the identified organism was resistant to the initial empirical therapy of tobramycin and piperacillin. In a further 13%, flucloxacillin was added to the empirical regimen when a sensitive Staphylococcus was identified. No significant differences between the culture-negative and culture-positive groups were observed in admission pulse, fever or admission neutrophil count. However, those patients with a central line had a higher incidence of having a pathogen isolated if their temperature was > 39.5 degrees C. The median length of stay was longer for patients with a pathogen isolated on blood culture. Admission blood cultures were positive in 53% of admissions with an initial neutrophil count > 1000 x 10(9)/mL. Each of these children had a central line. Only one child died of infection during the 2-year study period. This review supports the observations that gram-positive infection is now more common than gram-negative infection in children with cancer. Despite the management advantages a permanent central line affords it is clear those children with a central line have an increased rate of infection and there needs to be caution in their use. The most important is the observation that any fever > 39.5 degrees C in a child with a central line is likely to be associated with a documented infection irrespective of the neutrophil count. The clinical outcomes observed in the present study indicate that tobramycin and piperacillin are effective empirical treatments for suspected infection in children with cancer.

Chemotherapy for malignancy induces a remission in asthma symptoms and airway inflammation but not airway hyperresponsiveness

Inflammation with infiltrations of eosinophils and mast cells into the walls of airways is considered to increase airway hyperresponsiveness (AHR), which in turn characterizes asthma. We present a child with AHR in whom the clinical course of asthma was related to eosinophilic bronchitis. Our patient was admitted at age 6 months with bronchiolitis and at age 4 years with asthma. Inhaled corticosteroids were begun at age 7 years. At age 8 he developed a meningeal sarcoma. While on chemotherapy, his asthma symptoms resolved and he no longer required prophylactic asthma treatment. After 14 months off all chemotherapy, he again had mild episodic asthma. While receiving chemotherapy for malignancy, he had an admission with a coagulase negative staphylococcal bacteremia. During sputum induction with 4.5% saline, he developed cough, wheeze, and a 20% reduction in peak expiratory flow (220 to 180 L/min) that reversed after treatment with salbutamol. The sputum cell count was 1.7 x 10(6)/ml with 1.1 x 10(6) being neutrophils. Two weeks later and prior to the induction of the second sputum, a 21% increase in FEV1 was recorded after bronchodilator inhalation (82% to 99% of predicted). The second sputum contained 2.7 x 10(6)/ml cells with 1.6 x 10(6)/ml neutrophils. Neither eosinophils nor mast cells were identified in the sputum. A third sputum obtained 14 months after the cessation of chemotherapy showed a sputum cell count of 16 x 10(6)/ml, with 11.6 x 10(6) neutrophils and 0.4 x 10(6) eosinophils; no mast cells were detected. A reversible 15% reduction in FEV1 was detected on hypertonic saline challenge testing. This boy had persistent airway hyperreactivity and reversible airways obstruction on three occasions during and following chemotherapy. When he developed asthma symptoms, his sputum contained neutrophils and eosinophils; while on chemotherapy his sputum did not contain eosinophils and he was symptom-free and off all asthma therapy. One can speculate that chemotherapy for malignancy can induce a remission in asthma symptoms but not AHR, and remission in symptoms is associated with a lack of eosinophilic or mast cell infiltrates in the sputum.

The observed global warming record: what does it tell us?

Global, near-surface temperature data sets and their derivations are discussed, and differences between the Jones and Intergovernmental Panel on Climate Change data sets are explained. Global-mean temperature changes are then interpreted in terms of anthropogenic forcing influences and natural variability. The inclusion of aerosol forcing improves the fit between modeled and observed changes but does not improve the agreement between the implied climate sensitivity value and the standard model-based range of 1.5-4.5 degrees C equilibrium warming for a CO2 doubling. The implied sensitivity goes from below the model-based range of estimates to substantially above this range. The addition of a solar forcing effect further improves the fit and brings the best-fit sensitivity into the middle of the model-based range. Consistency is further improved when internally generated changes are considered. This consistency, however, hides many uncertainties that surround observed data/model comparisons. These uncertainties make it impossible currently to use observed global-scale temperature changes to narrow the uncertainty range in the climate sensitivity below that estimated directly from climate models.

Necrotizing cutaneous infection caused by Curvularia brachyspora in an immunocompetent host

A case of necrotizing cutaneous infection in an immunocompetent host caused by the dematiaceous fungus, Curvularia brachyspora is presented. A 58-year-old man was transferred to the Prince Henry Hospital for treatment of necrotizing cellulitis involving both thighs that developed following cryotherapy. The patient did not respond to antibacterial therapy and hyperbaric oxygen. He was empirically commenced on intravenous amphotericin B and began to respond even before the pathogen C. brachyspora was identified.

Effects induced by feeding organochlorine-contaminated carp from Saginaw Bay, Lake Huron, to laying White Leghorn hens. I. Effects on health of adult hens, egg production, and fertility

This study was conducted to determine the effects of consumption of halogenated hydrocarbon compounds, primarily polychlorinated biphenyls (PCBs), contained in Great Lakes fish by the domestic chicken (Gallus domesticus). In this article we report the results of feeding White Leghorn hens for a period of 8 wk diets that contained 31-35% ocean fish and/or carp (Cyprinus carpio) from Saginaw Bay, Lake Huron, MI, which provided 0.3 (control), 0.8 (low-dose group), or 6.6 (high-dose group) mg PCB/kg, wet weight (ww). These concentrations were analogous to 3.3, 26, or 59 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents (TEQs)/g diet, ww, respectively. There were no significant effects on feed consumption among the groups. An unexpectedly high incidence of fatty liver hemorrhagic syndrome (FLHS) was observed in hens from the control (78% FLHS) and low-dose (75% FLHS) groups when compared to the high-dose group (15% FLHS). Birds in the control and low-dose groups had a significant increase in liver and body weights. Significant decreases in egg production, weight, and fertility were immediate in all dose groups, with the effect being permanent in the control and low-dose groups. Although the incidence of FLHS was an unexpected complication, the fact that there were no significant effects on egg production, egg weights, or fertility in the high-dose group suggests that the no-observable-adverse-effect concentration (NOAEC) for these parameters is in excess of 26 mg total weathered PCBs/kg egg, ww. This value was the average concentration of PCBs in the high-dose group eggs during the last week of the study.

Effects induced by feeding organochlorine-contaminated carp from Saginaw Bay, Lake Huron, to laying White Leghorn hens. II. Embryotoxic and teratogenic effects

Carp from Saginaw Bay, Lake Huron, MI, was fed to White Leghorn chickens for a period of 8 wk. The diets contained 0.3 (control; 0% carp), 0.8 (3.4% carp), and 6.6 (35% carp) mg polychlorinated biphenyls (PCBs)/kg diet, by wet weight (ww). These concentrations corresponded to 3.3, 26, and 59 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents/g diet ww, respectively. Though the diets were not acutely toxic to the adult laying hens, dose- and time-dependent responses were observed in the embryos and chicks. Toxicity was manifested as a dose-dependent increase in embryo mortality and decreased hatching rates. Furthermore, embryos and chicks displayed various deformities, including (1) head and neck edema and hemorrhage, (2) abdominal edema and hemorrhage, (3) foot and leg deformities, (4) skull and brain deformities, (5) yolk-sac deformities, and (6) miscellaneous deformities. The types of deformities observed were similar to those reported for embryos and chicks of colonial waterbirds in Saginaw Bay, as well as in controlled studies where technical mixtures or individual congeners of polychlorinated diaromatic hydrocarbons (PCDAHs) were fed to chickens. Increasing concentrations of carp also significantly affected the various organ weights in 18-d embryos and hatched chicks. At 18 d of incubation, weights of the embryos' livers were directly proportional to the concentration of PCBs in the diets. The weights of the spleens and bursae were inversely proportional to the dietary PCB concentration. After 3 additional days of incubation, significant effects in body, brain, liver, heart, and bursa weights were observed in hatched chicks. The concentrations of total PCBs, as well as 2,3,7,8-TCDD equivalents (TEQs) in the diets, were in the range of those that have been shown to cause similar adverse effects in other species. This study has shown that fish, the primary food source of colonial waterbirds in Saginaw Bay, are capable of causing adverse reproductive effects in a model avian species, the chicken. However, due to differences in the relative potency to cause effects on different endpoints in different species, the results of this study should not be used to predict the threshold for effects in other species.