Bioaccumulation of heavy metals in fish and Ardeid at Pearl River Estuary, China.

Sediment, fish (tilapia, Oreochromis mossambicus and snakehead, Channa asiatica), eggs and eggshells of Little Egrets (Egretta garzetta) and Chinese Pond Herons (Ardeola bacchus) were collected from Mai Po Ramsar site of Hong Kong, as well as from wetlands in the Gu Cheng County, Shang Hu County and Dafeng Milu National Nature Reserve of Jiangsu Province, China between 2004 and 2007 (n=3-9). Concentrations of six heavy metals were analyzed, based on inductively coupled plasma optical emission spectrometry (ICP-OES). Significant bioaccumulations of Cd (BAF: 165-1271 percent) were observed in the muscle and viscera of large tilapia and snakehead, suggesting potential health risks to the two bird species, as the fishes are the main preys of waterbirds. Significant (p<0.01) linear relationships were obtained between concentrations of Cd, Cr, Cu, Mn, Pb and Zn in the eggs and eggshells of various Ardeid species, and these regression models were used to extrapolate the heavy metal concentrations in the Ardeid eggs of Mai Po. Extrapolated concentrations are consistent with data in the available literature, and advocate the potential use of these models as a non-invasive sampling method for predicting heavy metal contamination in Ardeid eggs.

Activation of the cnidarian oxidative stress response by ultraviolet radiation, polycyclic aromatic hydrocarbons and crude oil.

Organisms are continuously exposed to reactive chemicals capable of causing oxidative stress and cellular damage. Antioxidant enzymes, such as superoxide dismutases (SODs) and catalases, are present in both prokaryotes and eukaryotes and provide an important means of neutralizing such oxidants. Studies in cnidarians have previously documented the occurrence of antioxidant enzymes (transcript expression, protein expression and/or enzymatic activity), but most of these studies have not been conducted in species with sequenced genomes or included phylogenetic analyses, making it difficult to compare results across species due to uncertainties in the relationships between genes. Through searches of the genome of the sea anemone Nematostella vectensis Stephenson, one catalase gene and six SOD family members were identified, including three copper/zinc-containing SODs (CuZnSODs), two manganese-containing SODs (MnSODs) and one copper chaperone of SOD (CCS). In 24 h acute toxicity tests, juvenile N. vectensis showed enhanced sensitivity to combinations of ultraviolet radiation (UV) and polycyclic aromatic hydrocarbons (PAHs, specifically pyrene, benzo[a]pyrene and fluoranthene) relative to either stressor alone. Adult N. vectensis exhibited little or no mortality following UV, benzo[a]pyrene or crude oil exposure but exhibited changes in gene expression. Antioxidant enzyme transcripts were both upregulated and downregulated following UV and/or chemical exposure. Expression patterns were most strongly affected by UV exposure but varied between experiments, suggesting that responses vary according to the intensity and duration of exposure. These experiments provide a basis for comparison with other cnidarian taxa and for further studies of the oxidative stress response in N. vectensis.

Inhibition of larval swimming activity of the coral (Platygyra acuta) by interactive thermal and chemical stresses.

This study examined the interactive effects of copper and elevated temperature and subsequent depuration on Platygyra acuta coral larvae. Larval mortality and motility were significantly affected by copper alone (70% and 100% inhibition respectively). Their respective lethal/inhibitory concentration (LC50/IC50) were 10-130% and 86-193% higher than those reported for other larvae. Temperature (ambient, 27°C and elevated, 30°C) alone and the combination of temperature and copper did not significantly affect both endpoints. This study provides the first quantitative data on depuration effect on resumption of larval motility after copper exposure, although no sign of larval recovery was observed. These findings suggest that the effects of copper pollution outweigh the thermal tolerance of coral larvae. High LC50 and IC50 recorded may be unique for corals from marginal reefs like Hong Kong which have already been exposed to high levels of copper pollution.

Biota-sediment accumulation factor (BSAF), bioaccumulation factor (BAF), and contaminant levels in prey fish to indicate the extent of PAHs and OCPs contamination in eggs of waterbirds.

Samples of pond sediment, fish, and shrimp were collected from the Ramsar site at Mai Po marshes, Hong Kong (south China), and samples of pond sediment, fish, and shrimp, as well as eggs of water birds (Chinese Pond Herons (Ardeola bacchus) and Little Egrets (Egretta garzetta)), were collected from two smaller wetland sites at Jiangsu Province (mid-China), between 2004 and 2007. Accumulation levels of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the biota were used to calculate biota-sediment accumulation factor (BSAF) and bioaccumulation factor (BAF). For fish and shrimp, BSAFs of OCPs (3.8-56) were greater than those of PAHs (0.12-6.3). BSAFs and BAFs of 11-79 and 4-34, respectively, were registered for OCPs in eggs of the birds and were greater than those for PAHs (0.11-1.5 and 0.02-1.3, respectively). Assuming that fish were the main prey of the birds, greater bioaccumulation of OCPs was detected for both bird species (BAFs =4.5-34), while accumulation of PAHs was only detected in Little Egret (BAF=1.3). A significant linear relationship (p<0.01) was observed between concentrations of OCPs in bird eggs and in the prey fish. The present study provides a new possibility of using OCP levels detected in prey fish to predict the extent of OCPs contamination in eggs of waterbirds including the endangered species, as a noninvasive method.

Ecotoxicological study on sediments of Mai Po marshes, Hong Kong using organisms and biomarkers.

Sediments from Mai Po Ramsar site, Hong Kong were in general shown to be highly toxic based on the results of four toxicity tests (Microtox solid-phase test, Daphnia mortality test, algal [Microcystis aeruginosa] growth inhibition test and ryegrass [Lolium perenne] seed germination/root elongation test). Sediment of the mudflat (which is open to Deep Bay, i.e., the pollution source) was the most toxic while sediment of gei wai 24g (an enclosed freshwater pond) was the least toxic. Results of biomarker studies (tilapia hepatic metallothionein; glutathione (GSH) and EROD activity using H4IIE rat hepatoma cell) were also concordant with those in the toxicity tests. Significant liner relationships (p<0.01) were found between GSH contents in the rat hepatoma cells and PAHs, OCPs contents in the sediment extracts. It is recommended that the present suite of bioassays is useful and is biologically relevant for future ecotoxicological studies focusing on similar wetlands.

Risk assessment of residual DDTs in freshwater and marine fish cultivated around the Pearl River Delta, China.

Six species of freshwater fish collected from 10 fishponds in Shunde and Zhongshan, China, four species of marine fishes collected from different mariculture farms [four in Hong Kong (Tung Lung Chau, Ma Wan, Cheung Chau and Kat O) and two in mainland China (Daya Bay and Shenzhen)] together with feed (both trash fish and commercial pellets) and sediment were analyzed for DDTs. Total DDTs in freshwater fish flesh decreased in the order of: carnivores [1742 microg/kg lipid weight (l.w.)] > herbivores (165 microg/kg, l.w.) > omnivores (42.5 microg/kg, l.w.), with the highest concentration detected in mandarin fish (Siniperca chuatsi) (2641 microg/kg, l.w.). For marine fish, snubnose pompano (Trachinotus blochii) and orange-spotted grouper (Epinephelus coioides) collected in Ma Wan contained elevated levels of total DDTs (2590 and 2034 microg/kg l.w., respectively). Trash fish used in both freshwater and marine fish farms contained significantly higher levels (86.5-641 microg/kg l.w.) (p < 0.05) of DDTs than in commercial pellets, but correlations between DDT levels in fish feed and muscle were not significant. The elevated biota-sediment accumulating factor for tilapia (Tilapia mossambicus) (24.1) indicated that accumulation of DDTs from sediment to the fish was evident. It can be concluded that trash fish should not be used for fish culture in order to lower the level of residual DDTs in fish muscle.

Clinical risk factors for obstructive sleep apnoea in children.

OBJECTIVE: To identify the clinical factor(s) that identify obstructive sleep apnoea syndrome (OSAS) in children. METHODS: A prospective study of children referred to the sleep clinic of the paediatric department was conducted in a public non-teaching regional hospital in Hong Kong. A standard questionnaire was administered and overnight sleep polysomnography was performed in a consecutive series of patients. Logistic regression analysis was performed to obtain significant risk factors for prediction of OSAS in this series of patients. RESULTS: Sixty-two children were enrolled into the study and 22 were diagnosed to have OSAS. Logistic regression analysis showed that, among all the answers, 'snoring every night' is the single most significant risk factor (p<0.0001) to predict OSAS. 'Snoring every night' has a sensitivity of 91% and specificity of 75% for OSAS patients. It also has a positive predictive value of 67% and negative predictive value of 94%. CONCLUSION: Snoring every night is an important risk factor in identifying OSAS in children. Priority for an overnight sleep polysomnogram should be given to those with this symptom.

Isolation of Helicobacter pylori from vomitus in children and its implication in gastro-oral transmission.

OBJECTIVE: The route of transmission of Helicobacter pylori (H. pylori) is unclear. Gastro-oral transmission via contaminated vomitus has been proposed as an important mode of transmitting H. pylori, especially in children. This pilot study attempted to isolate H. pylori from the vomitus of children. METHODS: Children presenting for evaluation with gastroenteritis-associated vomiting were studied. Fresh vomitus samples were collected for detection of H. pylori by bacteriological culture and polymerase chain reaction, (PCR). A rapid, whole blood test was used to determine the H. pylori status of patients. RESULTS: A total of 18 children with mean age of 6 yr were studied; four had a positive serology test. Among these four children, H. pylori was isolated from vomitus by culture in one child and by PCR in two. An 18-month-old girl with negative serology had H. pylori detected in vomitus by PCR. Six months later, she had seroconversion confirmed, suggesting that she had an acute H. pylori infection on initial presentation. CONCLUSIONS: This is the first study reporting successful isolation of H. pylori from naturally produced vomitus. The result implies that transmission of H. pylori infection by vomitus, especially in children, is possible.

Computed tomography-guided stereotactic aspiration and biopsy of a cystic metastatic adenocarcinoma of the pons.

We herein report a case of adenocarcinoma of the right main bronchus disseminated to the pons, left cerebral peduncle, and liver. Computed tomography-guided Cosman-Robert-Wells stereotactic aspiration of the cystic pontine lesion was performed through a transoccipital, transtentorial route and a catheter inserted in the cyst cavity that was connected to a subgaleal Ommaya reservoir for further aspiration and decompression. The choice of this approach to the lesion is briefly discussed.

Early experience with surgically inaccessible wide-necked intracranial aneurysm embolised with Guglielmi Electrically Detachable coils and electrothrombosis.

We describe our early successful experience with Guglielmi Electrically Detachable Coils (GDC) and electrothrombosis in treating a surgically inaccessible wide-necked intracranial aneurysm in a Chinese patient. The precautions taken to prevent unnecessary complications while performing this technique was also described. It provides a serious alternative to other less ideal types of embolising agents and direct surgery in treating patients with these difficult-to-treat aneurysms.

Identification of the human seminal TRH-like peptide pGlu-Phe-Pro-NH2 in normal human prostate.

Human and rat prostate contain thyrotropin-releasing hormone immunoreactivity (iTRH) including TRH and an uncharged TRH-like peptide. Recently the uncharged TRH-like peptide pGlu-Phe-Pro-NH2 was purified from human semen. To determine whether this peptide was of prostatic origin, human and rat prostate extracts were analyzed by ion-exchange chromatography and reversed-phase HPLC. The predominant uncharged iTRH comigrated exactly with synthetic pGlu-Phe-Pro-NH2 on HPLC and had identical affinity to pGlu-Phe-Pro-NH2 in a TRH radioimmunoassay. We conclude that prostate is a source of this peptide in humans and rats. This amidated TRH-like peptide may play a role in human reproductive physiology.

Expression of prostatic TRH-like peptides differs between species and between malignant and nonmalignant tissues.

Thyrotropin-releasing hormone-immunoreactive peptides (iTRH) were analyzed in normal rat and rabbit prostates and in human benign prostatic hyperplasia (BPH) and prostate cancer. Peptides were extracted from tissues, fractionated by anion and cation exchange chromatography, and analyzed by TRH radioimmunoassay. pGlu-Glu-Pro-NH2 predominated in rabbit, but accounted for only 10-15% of iTRH in rat and human BPH. Uncharged peptides predominated in rat and human prostate. Authentic TRH (pGlu-His-Pro-NH2) is not present in rabbit prostate, but may account for up to 25% of iTRH in rat and human prostate. iTRH was virtually absent in prostate cancer. These results demonstrate considerable heterogeneity in the expression of TRH-like peptides in the prostates of various animal species, and suggest decreased expression of these peptides in prostate cancer.

Mature testicular teratoma with vena caval invasion presenting as pulmonary embolism.

We report a case of mature testicular teratoma with invasion and thrombosis of the inferior vena cava that presented as recurrent pulmonary embolism. Treatment included radical orchiectomy, chemotherapeutic cytoreduction and, finally, resection of a massive retroperitoneal tumor with en bloc resection of the inferior vena cava using cardiopulmonary bypass and deep hypothermic circulatory arrest. Management is discussed and the literature is reviewed.

Transferring the location of a parasagittal lesion in CT to the scalp. Report of two cases.

By referring to the curve connecting the parietal eminences across the vertex, it is possible to transfer the location of a parasagittal lesion in the computed tomography (CT) scans to the scalp. The successful use of this new technique in 2 patients is reported.

Hepatic acetylator phenotype in bladder cancer patients.

We determined the hepatic acetylator phenotype in 130 patients with transitional-cell carcinoma (urothelioma) of the bladder and, previously in 157 normal control subjects. Eighty-three patients (63.8%) and 90 control subjects (57.4%) were slow acetylators (p greater than 0.05). Patients of both phenotypes did not differ in the consumption of tobacco and coffee. Seventy-five patients were not exposed to occupational risk for bladder cancer and the distribution of acetylator phenotype in them was similar to that of the control group. The other 55 patients had been employed in jobs with an elevated risk for urotheliomas; 41 (74.5%) were slow acetylators, which represented a significant excess over the incidence of slow acetylators in the control group (57.4%) (p less than 0.05); 15 of these patients had worked in jobs with carcinogenic arylamines proven in the workplace environment (11 were slow acetylators). Our results suggest that the slow acetylator phenotype can facilitate the development of urothelioma in individuals with occupational risk.