Accurate measures of changes in regional lung air volumes from chest x-rays of small animals.

Objective. To develop a robust technique for calculating regional volume changes within the lung from x-ray radiograph sequences captured during ventilation, without the use of computed tomography (CT).Approach. This technique is based on the change in transmitted x-ray intensity that occurs for each lung region as air displaces the attenuating lung tissue.Main results. Lung air volumes calculated from x-ray intensity changes showed a strong correlation (R2= 0.98) against the true volumes, measured from high-resolution CT. This correlation enables us to accurately convert projected intensity data into relative changes in lung air volume. We have applied this technique to measure changes in regional lung volumes from x-ray image sequences of mechanically ventilated, recently-deceased newborn rabbits, without the use of CT.Significance. This method is suitable for biomedical research studies,enabling quantitative regional measurement of relative lung air volumes at high temporal resolution, and shows great potential for future clinical application.

Integrated Assessment of Bioconcentration, Toxicity, and Hazards of Chlorobenzenes in the Aquatic Environment.

The evaluation of bioconcentration, toxicity, and hazard (BTH) of persistent lipophilic organic compounds (LOCs) are generally performed as separate rather than integrated assessments. There are adequate data sets in the literature for chlorobenzenes (CBs) consisting of (a) concentrations in aquatic biota (CB) and water (Cw) in the natural environment, (b) laboratory-derived bioconcentration factors (KB) and field concentration ratios (CR), the field equivalent factor of KB, (c) measured internal lethal concentrations (ILC50) and model estimated ILC50 calculated from KB and lethal concentrations (LC50), and (d) calculated hazard quotients in aquatic biota (HQB) and in water (HQW). However, there have been no integrated studies of those parameter values based on the respective lipid-based parameters (CBL, KBL, CRL, ILC50L, HQBL) performed. This study utilized the lipid-based parameters for CBs; a group of widely occuring, bioaccumulative, and toxic LOCs, and integrated those parameters into a bioconcentration-toxicity-hazard (BTHL) index. The values of the parameters were obtained from selected literature with known lipid contents of the aquatic biota. The results showed that the laboratory derived bioconcentration factors, KBLs, were comparable to the corresponding field based factors, CRLs, and the measured internal lethal concentrations, ILC50L, showed comparable values with the estimated ones. The integrated BTHL index was less than an order of magnitude or moderately acceptable for the assessment of variability, uncertainty, and predictive power of the index. This integrated assessment can be used to support decision making dealing with CBs in specific and LOCs in general, both in regional and global aquatic environments.

Evaluation of prediagnosis emergency department presentations in patients with active tuberculosis: the role of chest radiography, risk factors and symptoms.

INTRODUCTION: London has a high rate of tuberculosis (TB) with 2572 cases reported in 2014. Cases are more common in non-UK born, alcohol-dependent or homeless patients. The emergency department (ED) presents an opportunity for the diagnosis of TB in these patient groups. This is the first study describing the clinico-radiological characteristics of such attendances in two urban UK hospitals for pulmonary TB (PTB) and extrapulmonary TB (EPTB). METHODS: We conducted a retrospective cohort study using the London TB Register (LTBR) and hospital records to identify patients who presented to two London ED's in the 6 months prior to their ultimate TB diagnosis 2011-2012. RESULTS: 397 TB cases were identified. 39% (154/397) had presented to the ED in the 6 months prior to diagnosis. In the study population, the presence of cough, weight loss, fever and night sweats only had prevalence rates of 40%, 34%, 34% and 21%, respectively. Chest radiography was performed in 76% (117/154) of patients. For cases where a new diagnosis of TB was suspected, 73% (41/56) had an abnormal radiograph, compared with 36% (35/98) of patients where it was not. There was an abnormality on a chest radiograph in 73% (55/75) of PTB cases and also in 40% (21/52) of EPTB cases where a film was requested. CONCLUSIONS: A large proportion of patients with TB present to ED. A diagnosis was more likely in the presence of an abnormal radiograph, suggesting opportunities for earlier diagnosis if risk factors, symptoms and chest radiograph findings are combined.

Evaluation of serum inflammatory biomarkers as predictors of treatment outcome in pulmonary tuberculosis.

OBJECTIVE: To evaluate C-reactive protein (CRP), globulin and white blood cell (WBC) count as predictors of treatment outcome in pulmonary tuberculosis (PTB). METHODS: An observational study of patients with active PTB was conducted at a tertiary centre. All patients had serum CRP, globulin and WBC measured at baseline and at 2 months following commencement of treatment. The outcome of interest was requirement for extension of treatment beyond 6 months. RESULTS: There were 226 patients included in the study. Serum globulin 45 g/l was the only baseline biomarker evaluated that independently predicted requirement for treatment extension (OR 3.42, 95%CI 1.597.32, P 0.001). An elevated globulin level that failed to normalise at 2 months was also associated with increased requirement for treatment extension (63.9% vs. 5.1%, P 0.001), and had a low negative likelihood ratio (0.07) for exclusion of requirement for treatment extension. On multivariable analysis, an elevated globulin that failed to normalise at 2 months was independently associated with requirement for treatment extension (OR 6.13, 95%CI 2.2316.80, P 0.001). CONCLUSIONS: Serum globulin independently predicts requirement for treatment extension in PTB and outperforms CRP and WBC as a predictive biomarker. Normalisation of globulin at 2 months following treatment commencement is associated with low risk of requirement for treatment extension.

The use of thoracic computed tomography scanning and EBUS-TBNA to diagnose tuberculosis of the central nervous system: two case reports.

Herein, we report two cases of tuberculosis (TB) of the central nervous system where accessing the cerebrospinal fluid for diagnostic purposes was relatively or absolutely contraindicated at presentation. The finding of mediastinal lymphadenopathy on thoracic computed tomography scans, which was not visible on plain chest radiography, allowed endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) of these lymph nodes to support the diagnosis of TB in each patient and rule out other disease processes. EBUS-TBNA is a new bronchoscopic technique and in this case report appears to be a safe and useful option in the diagnosis of TB. Moreover, it proved to be so in cases where the main focus of disease was outside the thorax.

Degradation rate constants of steroids in sewage treatment works and receiving water.

Steroid estrogens are one of the most important groups of endocrine disrupting chemicals (EDCs) which can cause adverse effects on wildlife species and humans. Natural estrogens, including estrone (E1) and estradiol (E2), and synthetic estrogen 17alpha-ethinylestradiol (EE2) together contribute to most of the estrogenic activity in sewage effluents and receiving water. Degradation, particularly aerobic biodegradation was found to be the dominant removal mechanism in these environments. There are a number of factors such as temperature, pH, SRT, HRT and biomass concentration that can affect the rate of biodegradation. This paper reports the results of investigations in to the relationship between the equivalent biomass concentration and degradation rate constants for compounds E1, E2 and EE2 in various environments. It was found that a higher biomass concentration leads to higher rate constants, and relatively good linear correlations (R2 =0.73, 0.79 and 0.73) between the logarithm of the rate constants and the corresponding logarithm equivalent biomass concentration (EBC) values were obtained.

Trace organic contamination in biota collected from the Pearl River Estuary, China: a preliminary risk assessment.

The marine ecosystem of the Pearl River Delta, located on the southern coast of China, has been heavily exploited following the rapid economic growth that has occurred since the 1980s. This investigation aimed to elucidate trace organic contamination in marine biota inhabiting the Pearl River Delta area. Biota samples, including green-lipped mussels (Perna viridis), oysters (Crassostrea rivularis) and shrimp (Penaeus orientalis) were sampled from 16 stations fringing the Estuary. Elevated concentrations (on a dry weight basis) of polycyclic aromatic hydrocarbons (27.8-1041.0 ng/g), petroleum hydrocarbons (1.7-2345.4 microg/g), polychlorinated biphenyls (2.1-108.8 ng/g), DDTs (1.9-79.0 ng/g), and hexachlorocyclohexanes (n.d.-38.4 ng/g) were recorded. A human health risk assessment was conducted to estimate the risk to local residents associated with the consumption of biota collected from the Pearl River Estuary. The results indicated that PCBs were at levels that may cause deleterious health effects in populations that consume large amounts of seafood. However, it would be instructive to establish health criteria for trace organic contaminants that are specific to the local populations, in order to derive a more accurate and relevant health risk assessment.

A preliminary risk assessment of organochlorines accumulated in fish to the Indo-Pacific humpback dolphin (Sousa chinensis) in the Northwestern waters of Hong Kong.

The Indo-Pacific humpback dolphin is considered threatened due to several factors including pollution in Hong Kong and the risks due to consumption of fish tainted with polychlorinated biphenyls (PCBs) and organochlorine pesticides were assessed. Six species of fish Collichthys lucida, Pseudosciaena crocea, Johnius sp., Thryssa sp., Mugil sp. and Trichiurus sp., which comprise the main prey species of humpback dolphins were collected for analyses. Risks due to total PCBs, total TEQs, PCB 118 and the pesticides were assessed with the use of toxicity reference values as the threshold reference benchmarks. The calculated risk quotients (RQs) showed that the risks associated with organochlorines were generally low. The highest RQ was associated with total TEQs suggesting that dioxin-like PCBs may pose the highest risk to the dolphins. The HCHs, total PCBs and heptachlor had comparatively high RQs and thus they should also be the priority organochlorines that would require further investigation.

Risks posed by trace organic contaminants in coastal sediments in the Pearl River Delta, China.

Local marine environments in China's Pearl River Delta (PRD), the most rapidly developing region in one of the world's fastest growing economies, have been experiencing significant environmental stress during the past decades. This investigation was conducted to determine the status and trends of persistence organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-related compounds in marine sediments collected from sixteen coastal stations in the Pearl River Delta (PRD) in March 2003. Elevated concentrations of PAHs (94-4300 ng/g), PCBs (6.0-290 ng/g), PHCs (14-150 microg/g), and DDTs (1.4-600 ng/g) were detected in sediment samples. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-like activities in the sediment samples were estimated to range from 0.3 to 440 pg TCDD-EQ/g. Sediments collected from Xiashan contained the greatest concentrations of trace organic contaminations amongst all the sampling stations in the present study. The degree of trace organic contamination was, in general, more severe at stations situated along the west shores of the PRD than their counterparts in the east. A preliminary assessment was performed to examine the probable risks to the marine ecosystem due to POPs. The results showed that OC pesticide contamination in the PRD was particularly serious and might pose a threat to the health of the marine inhabitants.

A preliminary risk assessment of trace elements accumulated in fish to the Indo-Pacific Humpback dolphin (Sousa chinensis) in the northwestern waters of Hong Kong.

In order to assess the potential risks associated with consumption of contaminated prey items to the Indo-Pacific Humpback dolphin (Sousa chinensis), fish species (Collichthys lucida, Pseudosciaena crocea, Johnius sp., Thryssa sp., Mugil sp. and Trichiurus sp.) representing the main food items of the dolphin were collected from the northwestern waters of Hong Kong, including the Sha Chau and Lung Kwu Chau Marine Park, which form the main habitat of the dolphin in Hong Kong. Within these waters, there are several potential sources of pollution including significant inputs from the Pearl River catchment, several major sewage outfalls and a series of mud pits that receive contaminated dredged sediments. Concentrations of thirteen trace elements (Ag, As, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Se, V, and Zn) in the fish tissue were analyzed by inductively coupled plasma mass spectrometer (ICP-MS). An assessment of the risks of adverse effects on the dolphin due to consumption of tainted fish was undertaken using two toxic reference benchmarks, namely the reference dose (RfD) and toxicity reference value (TRV). The risk quotient (RQ) calculated for each element showed that the risks from consumption of fish were generally low and within safe limits. The risks associated with arsenic, cadmium and mercury were, however, elevated. The highest calculated RQ was associated with total arsenic; however, the majority of arsenic in marine organisms tends to be in the non-toxic organic form, and the actual risk to the dolphin due to this metalloid is likely to be lower.

Mussel-based monitoring of trace metal and organic contaminants along the east coast of China using Perna viridis and Mytilus edulis.

Green lipped mussels, Perna viridis, and blue mussels, Mytilus edulis, were collected from seven locations along the east coast of China in September and October 2001. The mussel tissues were analyzed for metals (Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg), and trace organic contaminants including organochlorine compounds (OCs), polycyclic aromatic hydrocarbons (PAHs; based on 24 individual PAHs), polychlorinated biphenyls (PCBs) and petroleum hydrocarbons (PHCs). Maximum concentrations of Ag, As, Cd, Cr, Ni, Pb, Se, Zn, Cu, Fe and Hg in the mussel tissues were 0.14, 26.76, 5.31, 15.72, 4.78, 2.93, 7.40, 231.0, 54.17, 1002 and 317.3 microg/g dry weight respectively. Levels of DDTs, PAHs, PCBs and PHCs in the mussel samples were 14-640, 456-3495, 1-13 ng/g and 621-2863 microg/g dry weight, respectively. Results of this study indicated that contaminant levels were, in general, higher or at least comparable to those reported in other local or regional studies. Mussel samples collected in Chongming Dao in Shanghai and Jiao Zhou Wan in Qingdao had significantly higher levels of metal and trace organic contaminants among the seven sampling stations. Examination of the contaminant profiles suggests that PHCs originated from petrogenic sources, while both petrogenic and pyrolytic sources were important for PAHs. The generally high levels of metals and organochlorine compounds are probably the result of increasingly intense industrial activities along the east coast of China. An assessment of potential risks to human health due to consumption of the mussels was undertaken for the metals, PCBs, DDTs and chlordanes, and the results indicated that all metals, except Ni, could pose a health risk to heavy seafood consumers, while Hg appears to be of concern even for low level consumers.

Risk to breeding success of fish-eating Ardeids due to persistent organic contaminants in Hong Kong: evidence from organochlorine compounds in eggs.

Eggs of two Ardeid species, the Little Egret (Egretta garzetta) and the Black-crowned Night Heron (Nycticorax nycticorax), were collected from two egretries located in the New Territories of Hong Kong with one located near the internationally acclaimed wetland reserve, the Mai Po Marshes, and the other in a remote site (A Chau). The eggs were analysed for organochlorine (OC) compounds including the DDTs, PCBs, hexachlorocyclohexanes (HCHs) and the chlordanes (CHLs). All of the OCs under investigation were detected in the eggs of both species with significantly higher levels in the Little Egret (DDTs, 560-2200; PCBs, 270-1700; CHLs, 81-470 ng g(-1) wet weight) than the Night Heron (DDTs, 210-1200; PCBs, 85-600; CHLs 59-75 ng g(-1) wet weight). The DDTs consisted mainly of DDE with levels ranging from 85% to 95% of the total. The HCHs were at about the same levels in both species (8.4-30 ng g(-1) wet weight). All of the OCs had linear concentration probability distributions on a log-normal basis which were used to evaluate exposure associated with these compounds as part of a probabilistic risk analysis. A linear dose/response relationship for the percentage reduction in the survival of young associated with DDE in eggs was developed. This probabilistic relationship was used to establish the threshold level (1000 ng g(-1) wet weight) at which there was a significant level of reduction in the survival of young above zero and the variability in DDE concentrations at this effect level. Using a threshold level of 1000 ng g(-1), the calculated Risk Quotient (RQ) had a 12.4% probability of RQ exceeding unity with the Night Heron, and 40.9% with the Little Egret. These results indicate that the DDTs in eggs would be expected to be associated with adverse effects on the survival of young of both species, particularly the Little Egret.

Chlorohydrocarbon pesticides in the Australian marine environment after banning in the period from the 1970s to 1980s.

The chlorohydrocarbon pesticides (CHPs) (principally DDT, dieldrin, hexachlorocyclohexane (HCH) including lindane, chlordane, heptachlor and heptachlorepoxide, aldrin and hexachlorobenzene (HCB)) were used extensively in Australia during the 1960s and 1970s. These were progressively banned from the 1970s with DDT being totally banned in 1987. The levels in marine waters are believed to have progressively declined as indicated by water in the Brisbane River, which consistently fell from maximum concentrations of about 1.7 microg/l in 1972-1973 to not detectable in 1986-1987. In some urban areas sediment concentrations, up to 1700 microg/kg dry weight, were recorded in the early 1990s which may reflect the reworking and exposure of older more contaminated material. Fish exhibited consistent occurrence of DDT, HCH, dieldrin and HCB through the 1970s to the 1990s. Maximum concentrations of DDT and dieldrin occurred generally in the 1970s at 40.3 and 8.8 microg/g wet weight, and minimums in the 1990s at 2.4 and 0.041 micro/g wet weight respectively. Inputs of dialdrin from sewage and DDT from the broad environment, reflected by the calculated daily human uptake in the diet, were shown to decline with half-lives of 1.1-1.5 and about 3 years respectively. This evidence suggests that banning of the CHPs has greatly reduced the inputs into the marine environment with consequent reductions in concentrations in biota but there is the occasional occurrence of relatively high concentrations.

A study of the biological partitioning behavior of n-alkanes and n-alkanols in causing anesthetic effects.

n-Alkanes and n-alkanols are two groups of common volatile organic compounds (VOCs) having potential anesthetic effects on workers and building occupants. A partition model based on the octanol-air partition coefficient was developed in this investigation to describe the biological partitioning of n-alkanes and n-alkanols in causing general anesthesia. Data on anesthetic potency (minimum alveolar concentration, MAC) for the test groups in rats were found to fit the model. The slight difference between the n-alkanes and n-alkanols in testing the model could be largely eliminated by correcting for the potential partial pressure gradients of the long-chain alkanes across the blood-brain barrier. The corrected MAC data for the two test groups fit well onto one common activity-partition regression line. This suggests that n-alkanes and n-alkanols may share a common biophase or mechanistic pathway for anesthesia. The present findings may provide some useful insight into setting anesthesia-based health standards for VOC mixtures.

Risk to breeding success of Ardeids by contaminants in Hong Kong: evidence from trace metals in feathers.

The feathers of two Ardeid species, the Little Egret (Egretta garzetta) and the Black-crowned Night Heron (Nycticorax nycticorax) were collected from six egretries and two egretries respectively, located in different areas in the New Territories of Hong Kong, including the Mai Po Marshes (within a Ramsar site). These feathers were digested and concentrations (microg/g dry weight) of copper (4.6-19.4), iron (8.1-641.3), manganese (0.4-19.4), zinc (51.3-183.5), lead (0.1-5.1), cadmium (0.01-0.15), chromium (0.06-1.7) and mercury (0.0-7.1) were determined by ICP-AES, ICP-MS and CVAAS. The levels of manganese, mercury and lead found were equal to or less than the concentrations found in previous investigations, reflecting a slight downward trend most apparent with lead. As a general rule, the levels of lead and mercury were higher in the egretries close to the polluted Deep Bay. A probabilistic risk assessment of the possible adverse effects on the breeding success of the Little Egret was carried out with respect to mercury, lead and cadmium. It was concluded that mercury (0.5-7.1 microg/g dry weight feathers) probably has had adverse effects at the Au Tau egretry of the Little Egrets, but there was no evidence of adverse effects at other egretries. The probabilistic analysis also indicated a low likelihood of adverse effects of mercury on the breeding of the Black-crowned Night Herons at A Chau (0.3-1.2 microg/g) and Mai Po Village (0.0-1.4 microg/g). The evidence for the effects of lead and cadmium was limited but suggested there may possibly be adverse effects with lead but not cadmium.

PAHs, PCDD/Fs, PCBs and HCB in leaves from Brisbane, Australia.

The concentrations of SOCs in leaves of an evergreen Australian native tree (Melaleuca leucadendra) and grass collected in Brisbane, Australia were determined. The concentrations of PCDD/Fs and PAHs in the leaf tissue were comparable to those reported for urbanised areas in other industrialised countries. A distinct difference in the compound profiles between the leaves of the two species was observed, with higher concentrations of the lower molecular mass PAHs and PCDD/Fs and lower concentrations of the higher molecular mass PAHs and PCDD/Fs in the Melaleuca leaves relative to the grass leaves. The interspecies differences are explained on the basis of the larger size of the lipophilic compartment (for compounds with low K(OA)) and the lower ratio of surface area to volume in the Melaleuca leaves.

Evidence for the presence of a widespread PCDD source in coastal sediments and soils from Queensland, Australia.

Recent studies have demonstrated the occurrence of elevated levels of higher chlorinated PCDDs in the coastal environment of Queensland, Australia. This study presents new data for OCDD contamination and full PCDD/F profile analysis in the environment of Queensland. Marine sediments, irrigation drain sediments and topsoil were collected from sites that were expected to be influenced by specific land-use types. High OCDD concentrations were associated mainly with sediments collected near the mouth of rivers which drain into large catchments in the tropical and subtropical regions. Further, analysis of sediments from irrigation drains could be clearly differentiated on the basis of OCDD contamination, with high concentrations in samples from sugarcane drains collected from coastal regions, and low concentrations in drain sediments from drier inland cotton growing areas. PCDD/F congener-specific analysis demonstrated almost identical congener profiles in all samples collected along the coastline. This indicates the source to be widespread. Profiles were dominated by higher chlorinated PCDDs, in particular OCDD whereas 2,3,7,8-substituted PCDFs were below the limit of quantification in the majority of samples. The full PCDD/F profile analysis of samples strongly resemble those reported for lake sediments from Mississippi and kaolinite samples from Germany. Strong similarities to these samples with respect to congener profiles and isomer patterns may indicate the presence of a similar source and/or formation process that is yet unidentified.