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Over the last decade, the introduction of microarray technology has had a profound impact on gene expression research. The publication of studies with dissimilar or altogether contradictory results, obtained using different microarray platforms to analyze identical RNA samples, has raised concerns about the reliability of this technology. The MicroArray Quality Control (MAQC) project was initiated to address these concerns, as well as other performance and data analysis issues. Expression data on four titration pools from two distinct reference RNA samples were generated at multiple test sites using a variety of microarray-based and alternative technology platforms. Here we describe the experimental design and probe mapping efforts behind the MAQC project. We show intraplatform consistency across test sites as well as a high level of interplatform concordance in terms of genes identified as differentially expressed. This study provides a resource that represents an important first step toward establishing a framework for the use of microarrays in clinical and regulatory settings.

Coronaviruses can infect a variety of animals including poultry, livestock, and humans and are currently classified into three groups. The interspecies transmissions of coronaviruses between different hosts form a complex ecosystem of which little is known. The outbreak of severe acute respiratory syndrome (SARS) and the recent identification of new coronaviruses have highlighted the necessity for further investigation of coronavirus ecology, in particular the role of bats and other wild animals. In this study, we sampled bat populations in 15 provinces of China and reveal that approximately 6.5% of the bats, from diverse species distributed throughout the region, harbor coronaviruses. Full genomes of four coronavirues from bats were sequenced and analyzed. Phylogenetic analyses of the spike, envelope, membrane, and nucleoprotein structural proteins and the two conserved replicase domains, putative RNA-dependent RNA polymerase and RNA helicase, revealed that bat coronaviruses cluster in three different groups: group 1, another group that includes all SARS and SARS-like coronaviruses (putative group 4), and an independent bat coronavirus group (putative group 5). Further genetic analyses showed that different species of bats maintain coronaviruses from different groups and that a single bat species from different geographic locations supports similar coronaviruses. Thus, the findings of this study suggest that bats may play an integral role in the ecology and evolution of coronaviruses.

Preparedness for a possible influenza pandemic caused by highly pathogenic avian influenza A subtype H5N1 has become a global priority. The spread of the virus to Europe and continued human infection in Southeast Asia have heightened pandemic concern. It remains unknown from where the pandemic strain may emerge; current attention is directed at Vietnam, Thailand, and, more recently, Indonesia and China. Here, we report that genetically and antigenically distinct sublineages of H5N1 virus have become established in poultry in different geographical regions of Southeast Asia, indicating the long-term endemicity of the virus, and the isolation of H5N1 virus from apparently healthy migratory birds in southern China. Our data show that H5N1 influenza virus, has continued to spread from its established source in southern China to other regions through transport of poultry and bird migration. The identification of regionally distinct sublineages contributes to the understanding of the mechanism for the perpetuation and spread of H5N1, providing information that is directly relevant to control of the source of infection in poultry. It points to the necessity of surveillance that is geographically broader than previously supposed and that includes H5N1 viruses of greater genetic and antigenic diversity.

Background: The graft protective effect of ulinastatin (UTI) against ischemia-reperfusion injury in small bowel transplantation (SBT) was verified with a rat SBT model. This study was carried out to investigate the effects of UTI on the accumulation and adhesion of neutrophils., Methods: Twenty-four recipients of rat SBTs were randomly divided into a control group and a UTI group. UTI was injected intravenously into the donor (before harvest of the graft) and into the recipient (50,000 U/kg/d). Variables included graft pathological score; myeloperoxidase content (MPO); expression of intercellular adhesion molecule-1 (ICAM-1) in the graft and plasma concentration of tumor necrosis factor (TNF) in the recipient., Results: The pathological changes of control group grafts were more significant than those of the UTI group. The content of MPO and expression of ICAM-1 in transplanted small intestines were lower among the UTI group as were plasma concentrations of TNF., Conclusions: UTI may ameliorate graft ischemia-reperfusion injury in SBT through decreasing accumulation and adhesion of neutrophils.

Introduction: We aimed to observe the trophic effects on graft structure and recipient metabolism of enteral rehabilitative therapy in rat small bowel transplantation (SBT)., Methods: Forty-eight recipients of rat allogeneic heterotopic SBT (Sprague-Dawley to Wistar rat) were divided into four groups randomly according to the presence of glutamine or growth hormone in the nutritional support regimen. We compared the histologic indices of graft mucosa and metabolic variables, including changes in body weight, nitrogen balance, urinary 3-methyl histidine excretion, and plasma albumin levels during 14 days after transplantation., Results: Glutamine and growth hormone promoted recovery of graft structure and improved recipient protein metabolism, as evidenced by indices of the enteral rehabilitative therapy., Conclusions: Glutamine and growth hormone potentiated their effects in enteral rehabilitative therapy, which produced potent trophic effects on graft structure and recipient metabolism in rat SBT.

Objective: To study a method for evaluating the quality of traditional Chinese medicine (TCM) according as their activity., Method: Combined with partial least squares (PLS), BP and RBF neural networks were selected to establish the model of quantitative composition-activity relationship (QCAR) due to their strong approximation capabilities for nonlinear function respectively. The activity of TCM was predicted with the QCAR model, and the quality of TCM was evaluated according to the predicted activity., Result & Conclusion: The proposed method was applied to evaluate the quality of Chuanxiong. The results indicated that, in the indexes including training error, prediction error and correlation coefficient, the established model is better than the model established by principal component regression or PIS regression. The new model can accurately represent the complicated nonlinear relationship between the components and the bioactivity of Chuanxiong. Consequently, this method has potential to evaluate the quality of TCM according to bioactivity.

Objective: To investigate the feasibility of intramuscular gene therapy for acute arterial ischemic diseases by use of plasmid pcDNA3-VEGF121 and to evaluate therapeutic efficiency of vascular endothelial growth factor (VEGF) by different routes of administration., Methods: Fifty New Zealand White rabbits were randomly assigned to either gelation sponge carrying-pcDNA3-VEGF121 (n = 18), intramuscular injection-pcDNA3-VEGF121 (n = 18), or pcDNA3 (as control group, n = 14). After ligation of the external iliac artery and complete excision of the femoral artery, 500 micrograms of the plasmid pcDNA3-VEGF121 were transfected into the muscles of the ischemic limb by gelation sponge carrying or direct intramuscular-injection. Immediately after gene transfection, blood flow of the internal iliac artery were measured. VEGF121 gene expression was detected by RT-PCR after 2 days, 1 week, 2 weeks, 3 weeks and 4 weeks of transfection. After 30 days, blood flow of the internal iliac artery, angiographic score and histological vessels of ischemic hindlimbs were measured respectively., Results: In the two VEGF-treated groups, VEGF121 mRNA expressed in the transfected ischemic muscles after 2 days and lasted 2 weeks. Immediately after gene transfection, blood flow of the internal iliac artery had no significant difference between three groups. After 30 days, blood flow of the internal iliac artery, angiographic score and capillary density were significantly greater in both VEGF-treated groups than in control group. Complexity of vascular branching and vessel density of gelation sponge-VEGF treated limbs were significantly greater when compared with the intramuscular-injection limbs., Conclusion: These findings suggest the feasibility of employing gene therapy of pcDNA3-VEGF121 could augment collateral development and tissue perfusion in an animal model of hindlimb ischemia, and gelation sponge carrying VEGF gene may respect a potential therapy methods.

The aim of this work was to examine the emission of N2O from soils following addition of nitrogen fertilizer with a nitrification inhibitor (+inh) or without the nitrification inhibitor(-inh) at different soil water regime. Higher soil moisture contents increased the total N2O emissions in all treatments with total emissions being 7 times larger for the CK and > 20 times larger for the fertilizer treatments at 85% WFPS (soil water filled pore space) than at 40% WFPS. The rates of N2O emissions at 40% WFPS under all treatments were small. The maximum emission rate at 55% WFPS without the nitrification inhibitor (-inh) occurred later (day 11) than those of 70% WFPS (-inh) samples (day 8). The inhibition period was 4-22 d for 55% WFPS and 1-15 d for 70% WFPS comparing the rates of N2O emissions treated (+inh) with (-inh). The maximum emission rates at 85% WFPS were higher than those at the other levels of soil water content for all treatments. The samples (+inh) released less N2O than (-inh) samples at the early stage. Nevertheless, N2O emissions from (+inh) samples lasted longer than in the (-inh) treatment. Changes in mineral N at 55%, 70% and 85% WFPS followed the same pattern. NH4(+) -N concentrations decreased while NO3(-) -N concentrations increased from the beginning of incubation. NH4(+) -N concentrations from 40% WFPS treatment declined more slowly than those of the other three levels of soil water content. Nitrification was faster in the (-inh) samples with 100% NH4(+) -N nitrified after 22 d (50% WFPS) and 15 d (70% and 85% WFPS). N2O emissions increased with soil water content. Adding N-fertilizer increased emissions of N2O. The application of the nitrification inhibitor significantly reduced total N2O emissions from 30.5% (at 85% WFPS) to 43.6% (at 55% WFPS).

Objective: To detect the effect of vascular endothelial growth factor (VEGF) on dendritic cells (DC) in patients with non-small cell lung cancer (NSCLC)., Methods: The measurement of DC in the peripheral blood was performed by a novel flow cytometric assay in 85 patients with NSCLC and 14 healthy volunteers. Enzyme-linked immunosorbent assay (ELISA) was used to measure the concentration of VEGF(165) in the plasma. CD(14)(+) peripheral blood mononuclear cells (PBMC) were cultured to obtain DC in vitro with cytokines. VEGF(165) was added to evaluate its effect on DC differentiation and survival. The phenotypes and apoptosis of cultured cells were detected by flow cytometry., Results: In comparison with healthy volunteers, the level of VEGF(165) was significantly increased (P < 0.05), while that of DC was significantly decreased (P < 0.01) in patients with NSCLC. No significant correlation was noted between the concentration of VEGF(165) and age, gender, differentiation and histological types in patients with NSCLC, neither was found in the level of DC (P > 0.05). The concentration of VEGF(165) was closely associated with TNM stage and distal metastasis (P < 0.05), while no correlation was found between the concentration of VEGF(165) and lymph node metastasis (P > 0.05). Significant correlations were noted between the level of DC in patients with NSCLC and TNM stage, lymph node metastasis and distal metastasis (P < 0.05). There was a negative correlation between the concentration of VEGF(165) and the level of DC (P < 0.05). Patients with abnormally elevated VEGF(165) showed significantly fewer DC. Cells cultured in vitro in the presence of VEGF(165) exhibited higher expression of CD(+)(14)(P = 0.000) and increased ratio of apoptic cells (P < 0.01), but decreased expression of CD(40), CD(86) and HLA-DR (P < 0.01), as compared to cells cultured without VEGF(165)., Conclusions: The level of DC and the concentration of VEGF in the peripheral blood can reflect the malignancy of NSCLC. NSCLC can over-express VEGF to inhibit DC differentiation and maturation to evade host immune surveillance.

Objective: To establish the chromatographic fingerprinting for identifying the habitat of Ligusticum chuangxiong., Method: HPLC system was applied to obtain the chromatograms of L. chuangxiong samples from different areas, and 15 peaks were measured from the chromatograms. Then some computer-based methods including principle component analysis, clustering analysis, similarity calculation and fisher factor analysis were applied for data analysis., Result: There was obvious difference among chromatographic fingerprints of L. chuangxiong samples from different areas. The 15 measured peaks could be used as the fingerprint features., Conclusion: Chromatographic fingerprinting can be used for identifying the habitat of L. chuangxiong.

Objective: To evaluate the adhesion of acute myeloid leukemia (AML) blasts to human umbilical vein endothelial cells (HUVECs) and the roles of intercellular adhesion molecule-1 (ICAM-1) and its ligand lymphocyte function associated antigen-1 (LFA-1) in binding of leukemic blasts to HUVECs., Methods: AML blasts attachment to unactivated or tumor necrosis factor alpha (TNF alpha) activated-endothelial cell monolayers was investigate in vitro; The adhesion of leukemic blasts co cultured with unactivated endothelial cells under static conditions at 37 degrees C for 24 hours was observed;The binding of neutrophils and unactivated endothelial cell monolayers exposed to supernatant of blasts were tested. ICAM-1 on endothelial cell surface and sICAM-1 of endothelial cell supernatant were determined by flow cytometry and ELISA detection. We also observed the adhesion of leukemic blasts in the presence of the adhesion blocking mAbs anti-ICAM-1 and anti-LFA-1., Results: This study has shown that the blast cells attached to unactivated endothelium was little (24.33 +/- 2.87)% and increased after exposure of endothelium to TNF alpha (81.87 +/- 4.08)% (n = 21, P < 0.001); The binding of blasts to endothelium also increased significantly after 24 hours co cultured with unactivated HUVEC (82.06 +/- 7.05)%, (n = 21, P < 0.001); The adhesion of neutrophils and unactivated endothelial cell monolayers exposed to supernatant of blasts was increased significantly (83.99 +/- 3.86)%, (n = 21, P < 0.001). Lower levels of ICAM-1 and sICAM-1 expression was detected on unactivated HUVECs (55.81 +/- 4.11)%, (0.839 +/- 0.236) microg/L respectively. Treatment of HUVECs with AML blasts supernatant for 24 hours increased the expression of ICAM-1 (65.36 +/- 5.97)%, (1.424 +/- 0.469) microg/L respectively (n = 21, P < 0.05) and anti-ICAM-1 and anti-LFA-1 significantly inhibited the adhesion of AML blasts attachment to TNF alpha activated-endothelial cell monolayers (20.12 +/- 1.73)%, (n = 10, P < 0.001)., Conclusion: Our results indicate that leukemic blasts have the ability to generate some factors that stimulate endothelial cell to secrete ICAM-1 ane to promote their own adhesion to vascular endothelium, interaction of ICAM-1 and its ligand LFA-1 has a key role in adhesion of leukemic blasts and HUVECs.

Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0.2 and 2 mM nitrate in nutrient solution. Nitrate treatments, imposed on 22-d-old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0.2 mM nitrate supply, nitrate uptake rates ranged from 0.6 to 1.5 mg N g(-1) d(-1) in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow-leafed lupin (L angustifolius) > white lupin (L albus). At 2 mM nitrate supply, nitrate uptake ranged from 1.7 to 8.2 mg N g(-1) d(-1) in the order: field pea > chickpea > white lupin > yellow lupin > narrow-leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0.2 mM nitrate was supplied, narrow-leafed lupinreleased the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mM nitrate, narrow-leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH- release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots.

Gingivitis and periodontitis, two frequently observed conditions in dogs, are primarily caused by bacterial plaque. Gingival crevicular fluid (GCF) and some of the biochemical substances contained in it are used diagnostically and to evaluate the success of treatment. A double-blind study using a crossover design was conducted to evaluate treatment with clindamycin hydrochloride on the amount of GCF and concentrations of its immune mediators (leukotriene B4 [LTB4], prostaglandin E2 [PGE2], and polymorphonuclear [PMN] elastase) in dogs. Ten dogs received clindamycin orally at 11 mg/kg/day for 14 days, and 10 dogs remained untreated as controls. After a 5-month rest period, the treatments were reversed. At the beginning and end of each series, the volume of GCF was measured and plaque and gingival indices were assessed on six reference teeth of each patient. Concentrations of LTB4, PGE2, and PMN elastase were determined by ELISA. In both series, plaque and gingival indices dropped significantly (P < or = .0001) in dogs treated with clindamycin. The volume of GCF also declined significantly (P< or = .0001) following treatment and levels of PGE2, PMN elastase, and LTB4 were significantly (P < or = .05) reduced in both series. The antimicrobial effect of clindamycin is not only due to high levels in the blood and saliva, but also to its presence in the gingival crevice.

We previously reported that transduction of IL-10 to rat liver allografts facilitates survival prolongation after orthotopic liver transplantation (OLT). In the current study, we examined Lewis hosts of IL-10-transduced allografts that had survived longer than 50 days in order to characterize peripheral blood mononuclear cells (PBMC). Phenotype analysis of the PBMC demonstrated an 18-fold increase in monocytes (CD11b/c(+)) with a massive increase in the monocyte/lymphocyte ratio. The monocytes expressed downregulated MHC class II (RT1B) but upregulated Fcgamma receptors in comparison with monocytes from the control hosts. The capacity of enriched monocytes to secrete TNF-alpha in response to LPS stimulation was downregulated in the survivors, while production of IL-10 was comparable. The monocytes from long-term survivors significantly inhibited the donor antigen stimulated secretion of IFN-gamma and IL-2. Monocytosis characterized by a shift to anti-inflammatory monocytes is associated with survival prolongation in the hosts of IL-10 transduced liver allografts., (Copyright 2001 Academic Press.)

Background: The appropriate surgical treatment for severe acute pancreatitis has been disputed for a long time. Herein we describe our experience with the laparoscopic treatment of this disease., Methods: Ten patients, seven male and three female, with an average age of 55 years were diagnosed with severe acute pancreatitis. All cases but one were found to be without biliary stones by ultrasonic and CT scans. Laparoscopic exploration, irrigation, drainage, and decompression of the pancreas were performed. Further treatment, including gastric decompression, irrigation via the drainage tubes, antibiotics, somatostatin, and parenteral nutrition, was continued in all patients following the laparoscopic procedures., Results: Nine patients recovered successfully; one died from adult respiratory distress syndrome (ARDS) soon after the operation. The hospital stay was 10-30 days., Conclusions: The laparoscopic era offers new hope for the treatment of severe acute pancreatitis. The technique can be used to determine the pathologic extent of the disease, to irrigate and drain the abdominal cavity, and to decompress the pancreas. Almost every surgical procedure for acute pancreatitis can be performed laparoscopically.

A reliable and less-invasive method is currently desired to assess the hemodynamic and functional alteration associated with brain death in the organs of donor candidates. Near-infrared spectroscopy (NIRs) was applied to rat liver in brain-dead donors for assessing tissue oxygenation and intracellular energy metabolism as a means of monitoring the liver viability in the brain-dead donor. Brain-dead rats were divided into 4 according to doses of epinephrine and vasopressin administered. Arterial ketone bodies ratio (AKBR), hyaluronic acid (HA), and NIRs monitoring of a liver graft were performed in the brain-dead phase before the grafts were transplanted into syngeneic rats. NIRs monitoring of oxygenated hemoglobin (Hb) and cytochrome aa3 oxidase (Cytaa3) redox state reflected changes in the hepatic microcirculation and intracellular oxygenation. The administration of high-dose epinephrine proved to be contraindicated due to catecholamine-induced hypoxic stress, while combined administration of adrenaline and vasopressin at an optimal dose rate was beneficial for preservation of the liver viability. The data obtained by NIRs were significantly correlated with the 7-day survival of recipients after liver transplantation. Thus, we conclude that NIRs is a sensitive and nondestructive method for monitoring alterations in the viability of brain-dead liver and can predict liver graft outcome.

The effects of dental amalgam on cytokine production by human peripheral blood mononuclear cells (PBMC) from healthy donors were analyzed. To induce cytokine production, PBMC were stimulated with lipopolysaccharide, phytohemagglutinin, or staphylococcal enterotoxin A and cultured for 48 h in the presence of either freshly prepared amalgam, aged amalgam, or amalgam-conditioned culture medium (ACCM). The concentrations of several cytokines were measured in PBMC supernatants by enzyme-amplified sensitivity immunoassays (EASIAs). Freshly prepared amalgam as well as ACCM induced a decrease in the production of interferon-gamma (IFN-gamma) and interleukin-10 (IL-10), and an increase in the concentrations of tumor necrosis factor-alpha (TNF-alpha). Both fresh amalgam and ACCM showed no effects on IL-2, IL-6, or granulocyte-macrophage colony-stimulating factor levels. Amalgam aged for 6 weeks did not affect the concentration of any of the above cytokines. To investigate which heavy metal cations released from amalgam caused the observed immunomodulatory effects, Cu2+, Hg2+, and Sn2+, which were detected in amalgam supernatants by inductively coupled plasma atomic spectrophotometry, were added as salts to the cultures. Cu2+ and Hg2+ induced a decrease in IFN-gamma and IL-10 levels, and Hg2+ an increase in TNF-alpha concentrations. Cytokine production was not significantly modulated by Sn2+. Under these experimental conditions, release of Ag+ into culture medium was not detectable. However, Ag+ markedly suppressed the production of IFN-gamma, IL-10, and TNF-alpha. In summary, our results show that fresh amalgam, but not amalgam aged for 6 weeks, causes changes in the cytokine pattern of PBMC in vitro, and that these effects are due to the release of Cu2+ and Hg2+.

Recent data suggest that distinct metal ions can be released from dental alloys or other biomaterials, and may cause toxic effects on various cells. In this study, the effects of 14 metal ions on histamine release from human blood basophils (n = 4), isolated tissue mast cells (lung n = 8, uterus n = 2, skin n = 1, gingiva n = 1), the basophil cell line KU-812, and the mast cell line HMC-1 were analyzed. Of the 14 metal ions, Ag+ (0.33 mM) and Hg2+ (0.33 mM) were found to induce release of histamine in blood basophils, KU-812, mast cells, and HMC-1. The effects of Ag+ and Hg2+ were dose dependent and were observed within 60 min of incubation. In primary mast cells and basophils, AU3+ (0.33 mM) also induced histamine release, whereas no effects of Au3+ on HMC-1 or KU-812 cells were seen. The other metal ions showed no effects on primary or immortal cells within 60 min. However, Pt4+ (0.33 mM) induced histamine liberation in HMC-1 and lung mast cells after 12 h. The Ag+- and Hg2+-induced rapid release of histamine from HMC-1 was associated with ultrastructural signs of necrosis, but not apoptosis. In contrast, prolonged exposure to Pt4+ (0.33 mM, 14 h) induced apoptotic cell death in HMC-1 cells, as assessed by electron microscopy and DNA analysis. Together, certain metal ions induce distinct cytopathogenic effects in mast cells and basophils. Whereas Ag+, Hg2+, and Au3+ cause direct toxicity, Pt4 causes cell death through induction of apoptosis. Whether such effects contribute to local adverse reactions to metal-containing biomaterials in vivo remains to be determined.

Recent data suggest that under certain conditions, various metal cations are released from dental alloys. These ions may produce adverse effects in various cell types in vivo. In this study, the cytopathogenic effects of 13 metal cations on murine L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells were analyzed in vitro. Several metal cations (dose range, from 0.0033 to 1.0 mmol/L) were found to induce dose-dependent inhibition of 3H-thymidine incorporation into cultured fibroblasts. The rank order of potency (lowest observed effect level, LOEL) for L-929 fibroblasts was: Ag+ > Pt4+ > Co2+ > In3+ > Ga3+ > Au3+ > Cu2+ > Ni2+ > Zn2+ > Pd2+ > Mo5+ > Sn2+ > Cr2+. A similar rank order of potency was obtained for primary human gingival fibroblasts: Pt4+ > Ag+ > Au3+ > In3+ > Ga3+ > Ni2+ > Co2+ > Zn2+ > Cu2+ > Cr2+ > Pd2+ > Mo5+ > Sn2+. In primary human mast cells, Ag+ and Au3+ caused dose-dependent toxic histamine release, whereas the other metal cations were ineffective over the dose range tested. To investigate the mechanism of metal cation-induced effects, we performed DNA as well as electron microscopic analyses on cultured fibroblasts. Both the DNA pattern and the ultrastructure of L-929 cells and gingival fibroblasts after exposure to cytopathogenic metal cations revealed signs of necrosis but no signs of apoptosis. Together, our data provide evidence that various metal cations produce dose-dependent cytopathogenic effects in distinct cell types, including human gingival fibroblasts and human tissue mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate the effect of benzene on murine splenic natural killer (NK) cell activity and interleukin-2 (IL-2) production, we exposed C57 BL/6 mice to benzene for 28 days. Benzene exposure via drinking water at doses of 27 and 154 mg/kg/day yielded the following results. 1) A decrease of spleen cell number was detected on the 14th day of benzene exposure at 154 mg/kg/day, and on the 21st and 28th day of exposure at both 27 mg/kg/day and 154 mg/kg/day. 2) NK activity per viable spleen cell was temporarily enhanced on the 21st day of exposure at doses of 27 and 154 mg/kg/day, thereafter returned to control levels. 3) IL-2 production was inhibited after 28 days of benzene exposure at 27 and 154 mg/kg/day. After ending exposure at doses of 27 mg/kg/day for 28 days, the decreased spleen cell number began to return to control levels from the 14th day on, and reduced IL-2 production returned to control levels. These results suggest that, NK cells are resistant to benzene toxicity, while IL-2 producing cells are sensitive. Thus, an imbalance in immune system was caused by toxic benzene action.

An enzyme capable of hydrolyzing 4-methylumbelliferyl phenylphosphonate to 4-methylumbelliferone and phenylphosphonic acid has been detected in human serum. It has a Km value of 1.72 x 10(-4) mol/L, has an optimum pH of 8.8-9.1 in Tris buffer, and shows maximum activity at 60 degrees C (30 min). The enzymic activity can be inhibited by Na3PO4, EDTA, and cysteine. We saw no effect of CuSO4, adenosine, thymidine, NaN3, diethyl p-nitrophenyl phosphate, p-chloromercuribenzoate, isopropyl fluorophosphate, or eserine on the enzymic activity. The enzyme cannot hydrolyze substrates of phosphodiesterase I or alkaline phosphatase. The enzyme is considered a phosphonate esterase.

A housewife cleaned toilet porcelain connected directly to a sewage storage tank with a mixture of cleaning agents; sodium hypochlorite (NaOCl) and hydrochloric acid (HCl) solutions. She complained of insomnia on the night after cleaning and suffered from severe metabolic acidosis with extremely low blood pH, PCO2 and bicarbonate values. She recovered from the acidosis after bicarbonate transfusion, plasmapheresis and plasma exchange. Permanent blindness ensued, however, from the third day after the event. These clinical symptoms suggested that the toxic substances responsible were chloramine and methyl chloride. Their generation was confirmed by in-vitro experiments, mixing NaOCl, HCl and pooled urine from normal people. In the simulation, the methyl chloride level far exceeded (100,000 ppm) the maximal allowable concentration recommended (ca 400 ppm) by the American Conference of Governmental Industrial Hygienists (ACGIH). Chloramine's toxic actions were confirmed using purified enzyme assay, and the inhibition of carbonic anhydrase and aldehyde dehydrogenase and the enhancement of superoxide dismutase activity were confirmed in neutral pH. The patient's clinical symptoms suggested that insomnia and permanent blindness seemed to be partly ascribable to chronic repetitive exposure to methyl chloride; catching a cold, drug intake and alcohol intake, in addition, precipitated the patient's visual loss. The possibility of this kind of intoxication with such a mixture of agents may lie latent in any situation where sewage or garbage are exposed to the open air.

The lymphocyte subsets in peripheral blood were determined in 73 cases of active pulmonary tuberculosis and 40 healthy subjects using rosette reagent of monoclonal antibody (McAb) to anti-T lymphocyte. The results showed that the percentages of T3, T4, T8, and T4/T8 ratio were 54.3 +/- 6.7%, 34.3 +/- 7.9%, 35.5 +/- 10.0%, 1.0 +/- 0.4 of patients group 66.3 +/- 7.9%, 45.3 +/- 6.3%, 29.9 +/- 5.8% and 1.6 +/- 0.3 of healthy control group respectively. There was statistically significant difference between these two groups (P less than 0.01).

The effects of benzene and its metabolites, phenol and hydroquinone, on natural killer (NK) activity in mouse spleen cells in vitro were studied. NK activity was evaluated by the specific release percentage of 51Cr from labeled YAC-1 cells after YAC-1 cells (target cells) were incubated with spleen cells (effector cells) of mice at ratios of effector cells to target cells (E/T) of 100/1, 50/1, and 25/1. Benzene was shown to inhibit NK activity at concentrations of 1 x 10(-5) M-5 x 10(-5) M, phenol at concentrations of 1 x 10(-7)-5 x 10(-5) M and hydroquinone at concentrations of 1 x 10(-6) M-1 x 10(5) M. Phenol and hydroquinone depressed NK activity in a dose-dependent manner. This study demonstrated that NK cell function of mouse spleen was depressed by exposure to benzene and its metabolites in vitro. Hydroquinone and phenol have very potent toxicity for suppression of immunosurveillance.