Characterization of HLA-A*33:03 epitopes via immunoprecipitation and LC-MS/MS

Human leukocyte antigen (HLA) class I has more than 18,000 alleles, each of which binds to a set of unique peptides from the cellular degradome. Deciphering the interaction between antigenic peptides and HLA proteins is crucial for understanding immune responses in autoimmune diseases and cancer. In this study, we aimed to characterize the peptidome that binds to HLA-A*33:03, which is one of the most prevalent HLA-A alleles in the Northeast Asian population, but poorly studied. For this purpose, we analyzed the HLA-A*33:03 monoallelic B cell line using immunoprecipitation of HLA-A and peptide complexes, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). In this study, we identified 5731 unique peptides that were associated with HLA A*33:03, and experimentally validated the affinity of 40 peptides for HLA-A*33:03 and their stability in HLA A*33:03-peptides complexes. To our knowledge, this study represents the largest dataset of peptides associated with HLA-A*33:03. Also, this is the first study in which HLA A*33:03-associated peptides were experimentally validated.

A novel anti-c-Kit antibody-drug conjugate to treat wild-type and activating-mutant c-Kit-positive tumors

c‐Kit overexpression and activating mutations, which are reported in various cancers, including gastrointestinal stromal tumor (GIST), small‐cell lung cancer (SCLC), acute myeloid leukemia, acral melanoma, and systemic mastocytosis (SM), confer resistance to tyrosine kinase inhibitors (TKIs). To overcome TKI resistance, an anti‐c‐Kit antibody–drug conjugate was developed in this study to treat wild‐type and mutant c‐Kit‐positive cancers. NN2101, a fully human IgG1, was conjugated to DM1, a microtubule inhibitor, through N‐succinimidyl‐4‐(N‐maleimidomethyl) cyclohexane‐1‐carboxylate (SMCC) (to give NN2101‐DM1). The antitumor activity of NN2101‐DM1 was evaluated in vitro and in vivo using various cancer cell lines. NN2101‐DM1 exhibited potent growth‐inhibitory activities against c‐Kit‐positive cancer cell lines. In a mouse xenograft model, NN2101‐DM1 exhibited potent growth‐inhibitory activities against imatinib‐resistant GIST and SM cells. In addition, NN2101‐DM1 exhibited a significantly higher anti‐cancer effect than carboplatin/etoposide against SCLC cells where c‐Kit does not mediate cancer pathogenesis. Furthermore, the combination of NN2101‐DM1 with imatinib in imatinib‐sensitive GIST cells induced complete remission compared with treatment with NN2101‐DM1 or imatinib alone in mouse xenograft models. These results suggest that NN2101‐DM1 is a potential therapeutic agent for wild‐type and mutant c‐Kit‐positive cancers.

Selection and Characterization of Monoclonal Antibodies Targeting Middle East Respiratory Syndrome Coronavirus through a Human Synthetic Fab Phage Display Library Panning

Since its first report in the Middle East in 2012, the Middle East respiratory syndrome-coronavirus (MERS-CoV) has become a global concern due to the high morbidity and mortality of individuals infected with the virus. Although the majority of MERS-CoV cases have been reported in Saudi Arabia, the overall risk in areas outside the Middle East remains significant as inside Saudi Arabia. Additional pandemics of MERS-CoV are expected, and thus novel tools and reagents for therapy and diagnosis are urgently needed. Here, we used phage display to develop novel monoclonal antibodies (mAbs) that target MERS-CoV. A human Fab phage display library was panned against the S2 subunit of the MERS-CoV spike protein (MERS-S2P), yielding three unique Fabs (S2A3, S2A6, and S2D5). The Fabs had moderate apparent affinities (Half maximal effective concentration (EC50 = 123-421 nM) for MERS-S2P, showed no cross-reactivity to spike proteins from other CoVs, and were non-aggregating and thermostable (Tm = 61.5-80.4 °C). Reformatting the Fabs into IgGs (Immunoglobulin Gs) greatly increased their apparent affinities (KD = 0.17-1.2 nM), presumably due to the effects of avidity. These apparent affinities were notably higher than that of a previously reported anti-MERS-CoV S2 reference mAb (KD = 8.7 nM). Furthermore, two of the three mAbs (S2A3 and S2D5) bound only MERS-CoV (Erasmus Medical Center (EMC)) and not other CoVs, reflecting their high binding specificity. However, the mAbs lacked MERS-CoV neutralizing activity. Given their high affinity, specificity, and desirable stabilities, we anticipate that these anti-MERS-CoV mAbs would be suitable reagents for developing antibody-based diagnostics in laboratory or hospital settings for point-of-care testing.

Low binding affinity and reduced complement-dependent cell death efficacy of ofatumumab produced using a plant system (Nicotiana benthamiana L.)

The plant protein production system is a platform that can not only reduce production costs but also produce monoclonal antibodies that do not have the risk of residual proteins from the host. However, due to the difference between post-translational processes in plants and animals, there may be a modification in the Fab region of the monoclonal antibody produced in the plant; thus, it is necessary to compare the antigen affinity of this antibody with that of the prototype. In this study, ofatumumab, a fully human anti-CD20 IgG1κ monoclonal antibody used for its non-cross resistance to rituximab, was expressed in Nicotiana benthamiana, and its affinities and efficacies were compared with those of native ofatumumab produced from CHO cells. Two forms of plant ofatumumab (with or without HDEL-tag) were generated and their production yields were compared. The HDEL-tagged ofatumumab was more expressed in plants than the form without HDEL-tag. The specificity of the target recognition of plant-derived ofatumumab was confirmed by mCherry-CD20-expressing HEK cells via immuno-staining, and the capping of CD20 after ofatumumab binding was also confirmed using Ramos B cells. In the functional equivalence tests, the binding affinities and complement-dependent cell cytotoxicity efficacy of plant-ofatumumab-HDEL and plant-ofatumumab without HDEL were significantly reduced compared to those of CHO-derived ofatumumab. Therefore, we suggest that although ofatumumab is not a good candidate as a template for plant-derived monoclonal antibodies because of its decreased affinity when produced in plants, it is an interesting target to study the differences between post-translational modifications in mammals and plants.

Distribution, fate and risk assessment of antibiotics in sewage treatment plants in Hong Kong, South China

Occurrence, removal, consumption and environmental risks of sixteen antibiotics were investigated in several sewage treatment plants (STPs) featuring different treatment levels in Hong Kong, China. Cefalexin, ofloxacin and erythromycin-H(2)O were predominant with concentrations of 1020-5640, 142-7900 and 243-4740 ng/L in influent, respectively; their mass loads were comparable to levels reported in urban regions in China and were at the high end of the range reported for western countries. The target antibiotics behaved differently depending on the treatment level employed at the STPs and relatively higher removal efficiencies (>70%) were observed for cefalexin, cefotaxime, amoxicillin, sulfamethoxazole and chloramphenicol during secondary treatment. ß-lactams were especially susceptible to removal via the activated sludge process while macrolides were recalcitrant (<20%) in the dissolved phase. Two fluoroquinolones, ofloxacin (4%) and norfloxacin (52%), differed greatly in their removal efficiencies, probably because of disparities in their pK(a) values which resulted in different sorption behaviour in sludge. Overall antibiotic consumption in Hong Kong was back-calculated based on influent mass flows and compared with available prescription and usage data. This model was verified by a good approximation of 82% and 141% to the predicted consumption of total ofloxacin, but a less accurate estimate was obtained for erythromycin usage. Risk assessment indicated that algae are susceptible to the environmental concentrations of amoxicillin as well as the mixture of the nine detected antibiotics in receiving surface waters.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in waterbird eggs of Hong Kong, China

Concentrations of PCDD/Fs, PCBs and PBDEs were measured in 56 egg samples collected from waterbirds of different species (Great Egret, Little Egret, Night Heron and Chinese Pond Heron) from different regions of Hong Kong (Ho Sheung Heung, Mai Po Village and Mai Po Lung Village) during 2000 and 2006. Dominance of 2,3,4,7,8-PeCDF indicates a signature associated with commercial usage of PCBs. Although no significant variations were observed within- and between-site in the levels of PCDD/Fs, coplanar PCBs and PBDEs, the concentrations of coplanar PCBs were much higher than PCDD/Fs. Similarity in composition profiles of PCDD/F and coplanar PCBs from different egretries is possibly associated with non-point sources of these contaminants to Hong Kong. Predominant accumulation of BDE-47, BDE-99 and BDE-100 suggested the penta-BDE technical mixtures usage in Hong Kong and its vicinity. Toxic equivalency and Monte Carlo simulation technique showed potential risks on waterbirds due to their exposure to PCDD/Fs.

Perfluorinated compounds and total and extractable organic fluorine in human blood samples from China

An improved extraction (ion pairing) and cleanup (ENVI-carb and solid phase extraction) method was developed for analysis of perfluorinated compounds (PFCs) in human whole blood samples from China. Ten PFCs including PFOS, PFHxS, PFOSA, PFDoDA, PFUnDA, PFDA, PFNA, PFOA, PFHpA, and PFHxA were detected in the blood samples (n=30) from five cities (Jintan, Nanjing, Guiyang, Beijing, and Shenyang). PFOS was found to be the dominant PFC ranging from 0.446-83.1 ng/mL. Total fluorine (TF) and extractable organic fluorine (EOF) also were measured in the blood samples using combustion ion chromatography for fluorine. Analysis of known PFCs and extractable organic fluorine showed that known PFCs could account for >70% of EOF in samples from Beijing, Shenyang, and Guiyang, whereas known PFCs could only account for approximately 30% of EOF in samples from Jintan. Results of the present study indicated the presence of substantial amounts of unidentified organic fluorine in human blood samples from Jintan. Characterization and identification of these unidentified fluorinated compounds will be instructive.

Historical trends of organic pollutants in sediment cores from Hong Kong

Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD and p,p'-DDE), hexachlorohexanes (HCHs) (alpha and gamma), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.

Removal of antibiotics from wastewater by sewage treatment facilities in Hong Kong and Shenzhen, China

Concentrations of nine antibiotics [erythromycin-H(2)O (ERY-H(2)O); trimethoprim (TMP); tetracycline (TET); norfloxacin (NOR); penicillin G (PEN G); penicillin V (PEN V); cefalexin (CLX); cefotaxim (CTX); and cefazolin (CFZ)] were measured in influent and effluent samples from four sewage treatment plants (STPs) in Hong Kong as well as in influent samples from one STP in Shenzhen. Levels of PEN V and CFZ were below method detection limits in all of the samples analyzed. CLX concentrations were the highest in most of the Hong Kong samples, ranging from 670 to 2900 ng/L and 240 to 1800 ng/L in influent and effluent samples, respectively, but CLX was not detected in the samples from Shenzhen. Comparatively lower concentrations were observed for ERY-H(2)O (470-810 ng/L) and TET (96-1300 ng/L) in the influent samples from all STPs in Hong Kong. CTX was found to be the dominant antibiotic in the Shenzhen STP influents with a mean concentration of 1100 ng/L, but occurred at lower concentrations in Hong Kong sewage. These results likely reflect regional variations in the prescription and use patterns of antibiotics between Hong Kong and Shenzhen. Antibiotic removal efficiencies depended on their chemical properties and the wastewater treatment processes used. In general, relatively higher removal efficiencies were observed for NOR (5-78%) and TET (7-73%), which are readily adsorbed to particulate matter, while lower removal efficiencies were observed for ERY-H(2)O (9-19%), which is relatively persistent in the environment. Antibiotics were removed more efficiently at Hong Kong STPs employing secondary treatment processes compared with those using primary treatment only. Concentrations of NOR measured in effluents from STPs in Hong Kong were lower than the predicted no-effect concentration of 8000 ng/L determined in a previous study. Therefore, concentrations of antibiotics measured in this preliminary study would be unlikely to cause adverse effects on microorganisms used in wastewater treatment processes at the sampled STPs.

Perfluorinated compounds in the Pearl River and Yangtze River of China

A total of 14 perfluorinated compounds (PFCs) were quantified in river water samples collected from tributaries of the Pearl River (Guangzhou Province, south China) and the Yangtze River (central China). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the two compounds with the highest concentrations. PFOS concentrations ranged from 0.90 to 99 ng/l and <0.01-14 ng/l in samples from the Pearl River and Yangtze River, respectively; whereas those for PFOA ranged from 0.85 to 13 ng/l and 2.0-260 ng/l. Lower concentrations were measured for perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluorooctanesulfoamide (PFOSA), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorononaoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA). Concentrations of several perfluorocarboxylic acids, including perfluorododecanoic acid (PFDoDA), perfluorotetradecanoic acid (PFTeDA), perfluorohexadecanoic acid (PFHxDA) and perfluorooctadecanoic acid (PFOcDA) were lower than the limits of quantification in all the samples analyzed. The highest concentrations of most PFCs were observed in water samples from the Yangtze River near Shanghai, the major industrial and financial centre in China. In addition, sampling locations in the lower reaches of the Yangtze River with a reduced flow rate might serve as a final sink for contaminants from the upstream river runoffs. Generally, PFOS was the dominant PFC found in samples from the Pearl River, while PFOA was the predominant PFC in water from the Yangtze River. Specifically, a considerable amount of PFBS (22.9-26.1% of total PFC analyzed) was measured in water collected near Nanjing, which indicates the presence of potential sources of PFBS in this part of China. Completely different PFC composition profiles were observed for samples from the Pearl River and the Yangtze River. This indicates the presence of dissimilar sources in these two regions.

Protease-modulated cellular uptake of quantum dots

Quantum dots (QDs) are often cell-impermeable and require transporters to facilitate crossing over cell membranes. Here we present a simple and versatile method that utilizes enzymes, matrix metalloprotease 2 (MMP-2) and MMP-7, to modulate the cellular uptake of QDs. QD-peptide conjugates could be efficiently taken up into cells after the MMP treatment. This enzyme-modulated cellular uptake of QDs may be applied to other nanoparticles for biological imaging and selective drug delivery into tumor cells.

Alkaline digestion and solid phase extraction method for perfluorinated compounds in mussels and oysters from South China and Japan

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), have been identified in the coastal waters of China and Japan. An alkaline digestion method, coupled with solid-phase extraction (SPE), and high-performance liquid chromatography interfaced with high-resolution electrospray tandem mass spectrometry was developed to determine PFCs in mussel and oyster samples from coastal waters of South China and Japan. These techniques produced adequate recoveries and reporting limits with small quantities of PFCs. Concentrations of individual PFCs in mussels and oysters from South China and Japan ranged from 113.6 to 586.0 pg/g, wet weight (ww) for PFOS, 63.1 to 511.6 pg/g, ww for perfluorohexane sulfonate, 9.3 to 30.1 pg/g, ww for perfluorobutane sulfonate and 37.8 to 2957.0 pg/g, ww for perfluorooctane sulfonamide. The quantification of perfluorinated carboxylates was compromised by interferences from carboxylates in the procedural blanks. Perfluoroundecanoate and perfluorononanoate had relatively great blank interferences, which resulted in relatively poor limits of quantification for these compounds. Some PFCs were only identified in a limited number of samples: perfluorododecanoate in samples from Tokyo Bay, Japan (195.9 pg/g, ww); and perfluorodecanoate in Fuzhou, China (131.7 pg/g, ww) and Tokyo Bay (118.6 pg/g, ww). The greatest concentrations of perfluorooctanoate, perfluoroheptanoate, and perfluorohexanoate were observed in samples from Tokyo Bay and Bei Hai, South China.

Perfluorooctanesulfonate and related fluorochemicals in human blood samples from China

Perfluorooctanesulfonylfluoride (POSF)-based compounds have been manufactured and used in a variety of industrial applications. These compounds degrade to perfluorooctanesulfonate (PFOS) which is regarded as a persistent end-stage metabolite and is found to accumulate in tissues of humans and wildlife. PFOS, perfluorohexanesulfonate (PFHxS), perfluorooctanoate (PFOA), and perfluorooctanesulfonamide (PFOSA) have been found in human sera from the United States. In this study, concentrations of PFHxS, perfluorobutanesulfonate (PFBS), PFOS, perfluorohexanoic acid (PFHxA), PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluoroundecanoic acid (PFUnDA), perfluorododecanoic acid (PFDoDA), and PFOSA were measured in 85 samples of whole human blood collected from nine cities (eight provinces) in China, including Shenyang (Liaoning), Beijing (Hebei), Zhengzhou (Henan), Jintan (Jiangsu), Wuhan (Hubei), Zhoushan (Zhejiang), Guiyang (Guizhou), Xiamen (Fujian), and Fuzhou (Fujian). Among the 10 perfluorinated compounds (PFCs) measured, PFOS was the predominant compound. The mean concentration of PFOS was greatest in samples collected from Shenyang (79.2 ng/mL) and least in samples from Jintan (3.72 ng/mL). PFHxS was the next most abundant perfluorochemical in the samples. No age-related differences in the concentrations of PFOA, PFOS, PFOSA, and PFHxS were observed. Gender-related differences were found,with males higher for PFOS and PFHxS, and females higher in PFUnDA. Concentrations of PFHxS were positively correlated with those of PFOS, while concentrations of PFNA, PFDA, and PFUnDA were positively correlated with those of PFOA. There were differences in the concentration profiles (percentage composition) of various PFCs in the samples among the nine cities.

Organochlorines and dioxin-like compounds in green-lipped mussels Perna viridis from Hong Kong mariculture zones

Concentrations of persistent organic pollutants including polychlorinated biphenyls (PCBs), organochlorine (OC) pesticides and dioxin-like compounds were measured in green-lipped mussels, Perna viridis, collected from seven mariculture zones in Hong Kong between September and October in 2002 in order to evaluate the status, spatial distribution and potential sources of pollution in these areas. Concentrations ranged from 300 to 4400 ng/g lipid weight for total OCs and 170-1000 ng/g lipid weight for total PCBs (based on 28 congeners). Relatively smaller DDT concentrations in mussels compared with previous studies suggest reduced discharges of DDTs from nearby regions into Hong Kong waters. Detection of a mixture of HCH isomers in the mussels indicated that Hong Kong waters were predominantly contaminated by technical HCHs rather than lindane. Mussel samples from all sampling locations elicited significant dioxin-like activity in the H4IIE-luc bioassay. The greatest magnitude of dioxin-like response (39 pg TEQ/g wet wt.) was detected in mussels from Ma Wan in the western waters of Hong Kong, which is strongly influenced by the Pearl River discharge. Human health risk assessment was undertaken to evaluate potential risks associated with the consumption of the green-lipped mussels. Risk quotient (RQ) for dioxin-like compounds was greater than unity suggesting that adverse health effects may be associated with high mussel consumption.

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.

Perfluorinated compounds in coastal waters of Hong Kong, South China, and Korea

Perfluorinated compounds (PFCs), such as perfluorooctanesulfonate (PFOS) and related compounds, have recently been identified in the environment. PFOS, the terminal degradation product of many of the PFCs, has been found globally in many wildlife species, as well as open ocean waters, even in remote regions far from sources. In this study, a solid-phase extraction procedure coupled with high-performance liquid chromatography interfaced to high-resolution mass spectrometry was used to isolate, identify, and quantify small concentrations of PFCs in seawater. These techniques were applied to investigate the local sources of PFCs in several industrialized areas of Asia and provide information on how the PFCs are circulated by coastal currents. Ranges of concentrations of PFOS in coastal seawaters of Hong Kong, the Pearl River Delta, including the South China Sea, and Korea were 0.09-3.1, 0.02-12, and 0.04-730 pg/mL, respectively, while those of perfluorooctanoic acid (PFOA) were 0.73-5.5, 0.24-16, and 0.24-320 pg/mL, respectively. Potential sources of PFCs include major industrialized areas along the Pearl River Delta of southern China and major cities of Korea, which are several of the fastest growing industrial and economic regions in the world. Detectable concentrations of PFOS and PFOA in waters of southern China were similar to those in the coastal marine environment of Japan and certain regions in Korea. Concentrations of PFCs in several locations in Korean waters were 10-100-fold greater than those in the other locations on which we report here. The spatial and seasonal variations in PFC concentrations in surface seawaters in the Pearl River Delta and South China Sea indicate the strong influence of the Pearl River discharge on the magnitude and extent of PFC contamination in southern China. All of the concentrations of PFOS were less than those that would be expected to cause adverse effects to aquatic organisms or their predators except for one location in Korea adjacent to an industrialized area. Hazard quotients were from <0.001 to 0.002 for aquatic animals and ranged from <0.001 to 17 for predatory birds.

In Vivo Imaging of Retinoic Acid Receptor Activity using a Sodium/Iodide Symporter and Luciferase Dual Imaging Reporter Gene

Retinoic acids are natural derivatives of vitamin A, and play important roles in modulating tumor cell growth by regulating differentiation, thus suggesting the potential use of these derivatives in cancer therapy and prevention. To visualize the intranuclear responses of functional retinoic acid receptors, we have developed a dual-imaging reporter gene system based on the use of sodium/iodide symporter (NIS) and luciferase in cancer cell lines. NIS and luciferase genes were linked with an internal ribosome entry site, and placed under the control of an artificial cis-acting retinoic acid responsive element (pRARE/NL). After retinoic acid treatment, I-125 uptake by pRARE/NL transfected cells was found to have increased by up to about five times that of nontreated cells. The bioluminescence intensity of pRARE/NL transfected cells showed dose-dependency. In vivo luciferase images showed higher intensity in retinoic acid treated SK-RARE/NL tumors, and scintigraphic images of SK-RARE/NL tumors showed increased Tc-99m uptake after retinoic acid treatment. The NIS/luciferase imaging reporter system was sufficiently sensitive to allow the visualization of intranuclear retinoic acid receptor activity. This cis-enhancer imaging reporter system may be useful in vitro and in vivo for the evaluation of retinoic acid responses in such areas as cellular differentiation and chemoprevention.

Nitrous oxide flux from landfill leachate-sawdust nitrogenous compost

Composted nitrogenous waste has the potential to produce excessive amounts of nitrous oxide (N2O), a potent greenhouse gas that also contributes to stratospheric ozone depletion. In this laboratory study, sawdust was irrigated with varying amounts of landfill leachate with high NH4+-N content (3950 mg l(-1)). Physicochemical properties, including the amount of N2O produced, were monitored during the composting process over 28 days. A rapid decline in NH4+-N in the first 4 days and increasing NO3--N for 11 days was followed by lower but stabilized levels of available-N, even with repeated leachate irrigation. Less than 0.03% of the leachate-applied N was lost as N2O. Higher leachate applications as much as tripled N2O production, but this represented a lesser proportion overall of the total nitrogen. Addition of glucose to the composting process had no significant effect on N2O production. The derived sawdust-leachate compost supported healthy growth of Sesbania rostrata. It is concluded that compost can be produced from sawdust irrigated with landfill leachate without substantial emission of N2O, although excessive flux of N2O remains about high application rates over longer time periods.

Septic metastatic endophthalmitis complicating Klebsiella pneumoniae liver abscess in a non-diabetic Chinese man

Septic metastatic endophthalmitis is a rare but serious disease. Endophthalmitis arising from Klebsiella pneumoniae liver abscess has been reported with diabetes mellitus as a major associated condition, but is rarely seen in patients without diabetes. A non-diabetic patient with liver abscess complained of right eye discomfort and floaters 3 days after admission. Both blood and liver aspirate cultured Klebsiella pneumoniae. The patient was treated initially with systemic and subconjunctival antibiotics followed by intravitreal antibiotics with successful visual salvation. Previous reports from the literature showed poor visual outcome despite treatment and delayed recognition was often the cause. Clinicians should be alert to endophthalmitis whenever a patient with Klebsiella pneumoniae liver abscess complains of ocular symptoms. Urgent ophthalmological assessment should be sought.

Primary human immunodeficiency virus infection: heightened awareness needed

Primary human immunodeficiency virus infection is a distinct medical syndrome which is often not diagnosed. The importance of its early recognition lies in the potential for early therapeutic intervention for the individual, with consequent public health benefits for the community at large. Diagnosis requires a high index of suspicion in a person with a history of potential exposure. Early treatment with combination antiretroviral therapy should be considered once the diagnosis has been established. We report a local case of primary human immunodeficiency virus infection in a patient who presented initially with fever, lymphadenopathy, generalised skin rash, dry cough, splenomegaly, and aseptic meningitis.

Plesiomonas shigelloides infection in Hong Kong: retrospective study of 167 laboratory-confirmed cases

OBJECTIVE

To study the epidemiological, clinical, and microbiological features of Plesiomonas shigelloides infection in Hong Kong.

DESIGN

Retrospective study.

SETTING

Infectious Disease Unit of a district hospital, Hong Kong.

PATIENTS

Patients with laboratory-confirmed cases of Plesiomonas shigelloides infection between 1 January 1995 and 31 December 1998.

MAIN OUTCOME MEASURES

Epidemiological and clinical data, antibiotic sensitivity, and clinical outcome.

RESULTS

There was an increasing trend in the number of isolates of Plesiomonas shigelloides obtained and the prevalence of the bacterium. A total of 197 isolates were obtained from 188 patients, and most isolates (172; 87.3%) were obtained during the summer. Clinical and epidemiological data were available for 167 patients (85 males, 82 females). Patient age ranged from 1 month to 95 years; the mean and median ages of the patients older than 15 years were 51.0 and 40.5 years, respectively (n=132). Only 35 (21.0%) of the 167 patients had a history of travel outside Hong Kong, whereas 21 (12.6%) had a history of consuming seafood or uncooked food; 39 (23.4%) had underlying medical conditions. Most patients (165; 98.8%) had symptoms of Plesiomonas shigelloides infection. Nine (5.4%) patients had had chronic diarrhoea for more than 2 weeks; watery and bloody diarrhoea was discharged by 122 (73.1%) and 42 (25.1%) of the patients, respectively. All 197 Plesiomonas shigelloides isolates were sensitive to ofloxacin, or levofloxacin and ceftriaxone. Resistance or partial resistance was recorded for ampicillin (72%), tetracycline (67%), co-trimoxazole (12%), and chloramphenicol (5%). The majority of patients (142/167; 85.0%) had self-limiting cases of infection, but 25 patients were given antibiotics for more severe symptoms at the time of presentation; there were two deaths.

CONCLUSIONS

The occurrence of Plesiomonas shigelloides infection in Hong Kong is increasing, although most cases of are self-limiting.

Prognostic significance of pathologic features of hepatocellular carcinoma. A multivariate analysis of 278 patients

BACKGROUND

In patients with hepatocellular carcinoma, surgical resection may offer a chance of cure. However, tumor recurrence is not infrequent after resection.

METHODS

To identify the pathologic factors that are of prognostic significance and predictive value in tumor recurrence, the authors studied 278 patients (243 men, 35 women) who had hepatectomy for hepatocellular carcinoma. Disease free and actuarial survival were correlated with 20 pathologic parameters of the resected specimens using multivariate analysis.

RESULTS

The median follow-up period was 23.6 months. The overall disease free survival rates at 1, 3 and 5 years were 42%, 23%, and 17%, respectively, and the overall actuarial survival rates for the corresponding time periods were 70%, 39%, and 28%, respectively. The results indicated that tumor encapsulation (P = 0.004) and heavy intratumor inflammatory infiltrates (P = 0.003) were independent favorable factors related to tumor recurrence. Negative resection margins (P = 0.001) and heavy intratumor inflammatory infiltrates (P = 0.003) were independent favorable factors correlated with survival.

CONCLUSIONS

From this analysis, it was determined that detailed histologic examination of resected specimens of hepatocellular carcinoma is important in assessing long term prognosis and stratification of patients for treatment.

Prognostic implication of proliferative markers MIB-1 and PC10 in esophageal squamous cell carcinoma

BACKGROUND

Proliferative markers are related to tumor behavior. The commonly used markers are proliferating cell nuclear antigen (PCNA) and Ki-67. The aim of this study is to evaluate the usefulness of MIB-1 (for Ki-67) and PC10 (for PCNA) in the assessment of the clinicopathologic features and prognosis in patients with esophageal squamous cell carcinoma.

METHODS

One hundred patients (88 males, 12 females; mean age, 63 years [range, 39 to 83 years]) with surgically resected esophageal squamous cell carcinoma (32 well differentiated, 51 moderately differentiated, and 17 poorly differentiated) were studied. The clinicopathologic features and survival data of these patients were noted. Representative tissue was collected from each tumor and immunohistochemical preparations for MIB-1 and PC10 were made.

RESULTS

The percentages of cells that tested positive for PC10 and MIB-1 were much higher in tumor cells than in nonneoplastic cells. The pattern of expression of both markers varied with the differentiation of the tumor. The results observed with MIB-1 staining were better than those with PC10; because MIB-1 had less background staining, as well as stronger and more uniform positive signals compared with PC10. Thus, further investigation was performed on MIB-1-stained sections. The tumor cell MIB-1 scores ranged from 169 to 964 positive cells per 1000 cells (mean 598 +/- 211; median, 636). Although it was significantly associated with the differentiation of the tumor (P = 0.0001), the score had no significant relationship to the tumor size, location, or stage, or to the patients' age and sex. The prognosis depended on the size and stage of the lesion. In Stage III lesions (n = 83), patients with MIB-1 scores below 300 had longer actual survival rates than those with a score of 300 or above. However, the survival rates of patients in the latter group were better if the greatest dimension of the tumor diameter was 7.5 cm or less.

CONCLUSIONS

Proliferative activity in esophageal squamous cell carcinoma, as defined by the MIB-1 immunohistochemical method, is significantly related to tumor differentiation. It is also potentially valuable as a prognostic marker in addition to its use in tumor staging and size.

Prognostic significance of pathologic features of hepatocellular carcinoma. A multivariate analysis of 278 patients

BACKGROUND

In patients with hepatocellular carcinoma, surgical resection may offer a chance of cure. However, tumor recurrence is not infrequent after resection.

METHODS

To identify the pathologic factors that are of prognostic significance and predictive value in tumor recurrence, the authors studied 278 patients (243 men, 35 women) who had hepatectomy for hepatocellular carcinoma. Disease free and actuarial survival were correlated with 20 pathologic parameters of the resected specimens using multivariate analysis.

RESULTS

The median follow-up period was 23.6 months. The overall disease free survival rates at 1, 3 and 5 years were 42%, 23%, and 17%, respectively, and the overall actuarial survival rates for the corresponding time periods were 70%, 39%, and 28%, respectively. The results indicated that tumor encapsulation (P = 0.004) and heavy intratumor inflammatory infiltrates (P = 0.003) were independent favorable factors related to tumor recurrence. Negative resection margins (P = 0.001) and heavy intratumor inflammatory infiltrates (P = 0.003) were independent favorable factors correlated with survival.

CONCLUSIONS

From this analysis, it was determined that detailed histologic examination of resected specimens of hepatocellular carcinoma is important in assessing long term prognosis and stratification of patients for treatment.

Overexpression of p53 in hepatocellular carcinomas: a clinicopathological and prognostic correlation

Overexpression of the p53 tumour suppressor gene is one of the most common abnormalities in primary human cancers and appears to be a result of point mutation within a highly conserved region of the gene with subsequent encoding for a mutant, more stable protein. In the study, 71 surgically resected hepatocellular carcinomas (HCC) were examined to study the expression of the p53 gene, its relation with clinicopathological parameters and its prognostic significance. Using immunohistochemical detection for mutant p53 protein with monoclonal antibody PAb1801, p53 overexpression was found in 22 tumours (31%) but in none of the non-tumorous liver specimens. Overexpression of p53 was more frequent in tumours with poor cellular differentiation (P = 0.01), in tumours > 5 cm in diameter (P = 0.05), and in those with giant cells present (P = 0.03) and, less significantly, of massive type of Eggel's classification (P = 0.06). It did not have any significant correlation with hepatitis B or C status, background liver disease or serum alpha-fetoprotein levels, nor was it related to tumour invasiveness (venous permeation, direct liver invasion and tumour microsatellite formation). In addition, the presence of p53 mutant protein did not influence tumour recurrence or patients' survival rates. The data suggested that p53 mutation in HCC was associated with a later stage of oncogenesis. However, it was not apparently related to tumour invasiveness/aggressiveness and prognosis.

Peripheral blood lymphocyte subsets after allogeneic bone marrow transplantation: reconstitution and correlation with the occurrence of acute graft-versus-host disease

Peripheral blood lymphocyte subsets were enumerated at regular intervals during the first year after allogeneic bone marrow transplantation (BMT) in 21 Chinese patients. Eight of these patients had acute graft-versus-host disease (GVHD) while they were assessed at the time of engraftment. Our results show in patients receiving allogeneic BMT: (1) T and NK cells were the predominant lymphocyte subsets in the early reconstitution stage while B cells were severely depleted; (2) absolute numbers of the major lymphocyte subsets normalised in 4-5 months; (3) an increased percentage of T cells that expressed the activation antigen HLA-DR and a reversed CD4:CD8 ratio were observed throughout the first 12 months after BMT; (4) patients with acute GVHD had significantly higher white cell count and NK cell percentage than those not complicated by acute GVHD.

Flow cytometric analysis of DNA ploidy in hepatocellular carcinoma

To examine the prognostic and pathobiologic significance of DNA content, the authors studied the surgically resected hepatocellular carcinomas of 69 patients by flow cytometric analysis. Homogeneity of DNA content within individual tumor nodules was present in 15 (88%) of 17 specimens examined. Similarly, homogeneity of DNA content in tumors having multiple nodules was found in 8 (73%) of 11 specimens. In 64 tumors with homogeneous DNA content evaluated further, DNA aneuploidy was present in 30 (46.9%) specimens, and the proportion of aneuploid tumors was similar in the large (> 5 cm in diameter, n = 35) and small (< or = 5 cm, n = 25) lesions, at 42.9% and 40%, respectively. Overall, the diploid tumors had serum alpha-fetoprotein levels increased to greater than 500 micrograms/mL more frequently than did the aneuploid tumors (P = .037). DNA content did not correlate significantly with hepatitis B surface antigen, presence of liver cirrhosis, cellular differentiation, tumor size, or tumor encapsulation. DNA content also did not influence tumor invasiveness in terms of liver invasion, presence of tumor microsatellites, or venous permeation. With multivariate Cox regression analysis, tumor encapsulation (P = .015), negative resection margin (P = .007), and DNA ploidy pattern stratified according to large and small tumors (P = .024) were favorable prognostic factors. In the small tumors, a diploid DNA pattern was associated with significantly better patient survival than was an aneuploid pattern (P = .012). In the large tumors, on the contrary, a diploid pattern was associated with poorer patient survival than was an aneuploid pattern (P = .029). The authors conclude that DNA ploidy pattern in hepatocellular carcinomas is homogeneous and stable. It supplements other predictors in prognostication when the lesions are stratified into small and large ones by tumor size. It is of particular importance as a predictor because it can be assessed preoperatively in needle-biopsy specimens.

Prognostic significance of proliferating cell nuclear antigen expression in hepatocellular carcinoma

BACKGROUND

Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in G1/S-phase of the cell cycle and therefore is related to cell proliferative activity. In an attempt to evaluate its prognostic significance and clinicopathologic correlation in patients with hepatocellular carcinoma (HCC), the proliferative activity was studied using immunohistochemical staining with monoclonal antibody to PCNA.

METHODS

Seventy-two patients (64 men, 8 women; mean age, 52 years [range, 24-77 years]) having HCC surgically resected were studied. Tumor and nontumor tissues were selected from each case and stained with PCNA antibody. Tumor and nontumor PCNA (T-PCNA and NT-PCNA) scores were assessed by counting the positive staining nuclei per 1000 cells.

RESULTS

The T-PCNA score ranged from 10 to 894 per 1000 cells (mean +/- standard deviation = 333 +/- 263). It was found to be significantly and positively associated with positive margin (P = 0.003), direct liver invasion by tumor (P = 0.021), and venous permeation (P = 0.020), features directly or indirectly related to tumor invasiveness. However, it had no significant association with tumor size, cellular differentiation, or patients' hepatitis B surface antigen (HBsAg) status. When the tumors were stratified into two groups with a T-PCNA score less than or equal to 200 and a T-PCNA score greater than 200, those patients with a T-PCNA score less than or equal to 200 had significantly longer disease-free survival (DFS) and actual survival (AS) rates than those with scores greater than 200 (median DFS and AS, 34.6 and 49.3 months and 7.7 and 19.1 months, respectively; P = 0.019 and 0.035 for DFS and AS, respectively). T-PCNA and NT-PCNA scores had no significant correlation with the HBsAg status of the patients.

CONCLUSIONS

Proliferative activity in HCC, as defined by PCNA immunohistochemical analysis, is significantly related to tumor invasiveness. It is also a potentially valuable prognostic factor in patients with this tumor.

Prognostic significance of proliferating cell nuclear antigen expression in hepatocellular carcinoma

BACKGROUND

Proliferating cell nuclear antigen (PCNA) is a nuclear protein synthesized in G1/S-phase of the cell cycle and therefore is related to cell proliferative activity. In an attempt to evaluate its prognostic significance and clinicopathologic correlation in patients with hepatocellular carcinoma (HCC), the proliferative activity was studied using immunohistochemical staining with monoclonal antibody to PCNA.

METHODS

Seventy-two patients (64 men, 8 women; mean age, 52 years [range, 24-77 years]) having HCC surgically resected were studied. Tumor and nontumor tissues were selected from each case and stained with PCNA antibody. Tumor and nontumor PCNA (T-PCNA and NT-PCNA) scores were assessed by counting the positive staining nuclei per 1000 cells.

RESULTS

The T-PCNA score ranged from 10 to 894 per 1000 cells (mean +/- standard deviation = 333 +/- 263). It was found to be significantly and positively associated with positive margin (P = 0.003), direct liver invasion by tumor (P = 0.021), and venous permeation (P = 0.020), features directly or indirectly related to tumor invasiveness. However, it had no significant association with tumor size, cellular differentiation, or patients' hepatitis B surface antigen (HBsAg) status. When the tumors were stratified into two groups with a T-PCNA score less than or equal to 200 and a T-PCNA score greater than 200, those patients with a T-PCNA score less than or equal to 200 had significantly longer disease-free survival (DFS) and actual survival (AS) rates than those with scores greater than 200 (median DFS and AS, 34.6 and 49.3 months and 7.7 and 19.1 months, respectively; P = 0.019 and 0.035 for DFS and AS, respectively). T-PCNA and NT-PCNA scores had no significant correlation with the HBsAg status of the patients.

CONCLUSIONS

Proliferative activity in HCC, as defined by PCNA immunohistochemical analysis, is significantly related to tumor invasiveness. It is also a potentially valuable prognostic factor in patients with this tumor.