Tailoring structural and magnetic properties of Mn3-x Fe x Ga alloys towards multifunctional applications.

This study investigated the structural and magnetic properties of Mn3-x Fe x Ga alloys (x = 0, 0.2, 0.4, 0.6, 0.8, 1) under different heat-treatment conditions. A tetragonal structure was observed in samples that were heat treated at 623 K for three days followed by quenching in ice water. These tetragonal alloys present large coercive fields in the range 0.8-5 kOe and low saturation magnetization, and have great potential for application in spin-transfer torque-based devices. A hexagonal structure was observed in samples subjected to heat treatment at 883 K for three days following quenching in ice water. A moderate decrease in the coercive field has been observed for the hexagonal alloys compared with those with a tetragonal structure. However, the Mn3-x Fe x Ga alloys with a hexagonal structure exhibit other attractive magnetic properties, including collinear and non-collinear magnetic properties, holding high promise for technological applications. A face-centred-cubic (f.c.c.) structure was observed when subjected to annealing at 1073 K for three days followed by quenching in ice water. In contrast to the tetragonal and hexagonal structures, all f.c.c. alloys exhibit antiferromagnetic behaviour. This versatile material can display a wide range of multi-functionalities attributed to its tuneable crystal structure. This investigation will guide the design of multiple structures of these materials in order to utilise the wide functionalities for practical applications.

Isolation and characterization of novel polymorphic microsatellite markers for Epinephelus akaara.

In the present study, ten novel microsatellite markers were developed from an enriched-(CA)13 genomic library of Epinephelus akaara. The mean number of alleles per locus was 21.6, with a range of 12 to 33. Observed heterozygosity ranged from 0.767 to 0.967, and expected heterozygosity ranged from 0.831 to 0.975, with mean values of 0.877 and 0.923, respectively. Among the ten loci, three loci deviated from Hardy-Weinberg equilibrium after sequential Bonferroni's correction. These polymorphic microsatellite markers may be useful for studies on the population genetics of E. akaara.

Metabolic regulation of cancer cell side population by glucose through activation of the Akt pathway.

Side population (SP) cells within tumors are a small fraction of cancer cells with stem-like properties that can be identified by flow cytometry analysis based on their high ability to export certain compounds such as Hoechst 33342 and chemotherapeutic agents. The existence of stem-like SP cells in tumors is considered as a key factor contributing to drug resistance, and presents a major challenge in cancer treatment. Although it has been recognized for some time that tumor tissue niches may significantly affect cancer stem cells (CSCs), the role of key nutrients such as glucose in the microenvironment in affecting stem-like cancer cells and their metabolism largely remains elusive. Here we report that SP cells isolated from human cancer cells exhibit higher glycolytic activity compared to non-SP cells. Glucose in the culture environment exerts a profound effect on SP cells as evidenced by its ability to induce a significant increase in the percentage of SP cells in the overall cancer cell population, and glucose starvation causes a rapid depletion of SP cells. Mechanistically, glucose upregulates the SP fraction through ATP-mediated suppression of AMPK and activation of the Akt pathway, leading to elevated expression of the ATP-dependent efflux pump ABCG2. Importantly, inhibition of glycolysis by 3-BrOP significantly reduces SP cells in vitro and impairs their ability to form tumors in vivo. Our data suggest that glucose is an essential regulator of SP cells mediated by the Akt pathway, and targeting glycolysis may eliminate the drug-resistant SP cells with potentially significant benefits in cancer treatment.

Tumor-targeted gene therapy using Adv-AFP-HRPC/IAA prodrug system suppresses growth of hepatoma xenografted in mice.

Clinical efficacy of current therapies for hepatocellular carcinoma (HCC) treatment is limited. Indole-3-acetic acid (IAA) is non-toxic for mammalian cells. Oxidative decarboxylation of IAA by horseradish peroxidase (HRP) leads to toxic effects of IAA. The purpose of this study was to investigate the effects of a novel gene-targeted enzyme prodrug therapy with IAA on hepatoma growth in vitro and in vivo mouse hepatoma models. We generated a plasmid using adenovirus to express HRP isoenzyme C (HRPC) with the HCC marker, alpha-fetoprotein (AFP), as the promoter (pAdv-AFP-HRPC). Hepatocellular cells were infected with pAdv-AFP-HRPC and treated with IAA. Cell death was detected using MTT assay. Hepatoma xenografts were developed in mice by injection of mouse hepatoma cells. The size and weight of tumors and organs were evaluated. Cell death in tumors was assessed using hematoxylin and eosin-stained tissue sections. HRPC expression in tissues was detected using Reverse Transcriptase-Polymerase Chain Reaction. IAA stimulated death of hepatocellular cells infected with pAdv-AFP-HRPC, in a dose- and time-dependent manner, but not in control cells. Growth of hepatoma xenografts, including the size and weight, was inhibited in mice treated with pAdv-AFP-HRPC and IAA, compared with that in control group. pAdv-AFP-HRPC/IAA treatment induced cell death in hepatoma xenografts in mice. HRPC gene expressed only in hepatoma, but not in other normal organs of mice. pAdv-AFP-HRPC/IAA treatment did not cause any side effects on normal organs. These findings suggest that pAdv-AFP-HRPC/IAA enzyme/prodrug system may serve as a strategy for HCC therapy.

Intratracheal inoculation of severe acute respiratory syndrome coronavirus in monkeys Macaca rhesus.

An animal model for infection with Severe acute respiratory syndrome coronavirus (SARSCoV) was evaluated in monkeys Macaca rhesus. The monkeys were inoculated into the trachea with NS-I strain of SARS-CoV and the clinical manifestation of the illness was monitored. The clinical samples collected from infected monkeys were examined by immumnofluorescence assay (IFA), pathological inspection, RTPCR, and by virus isolation. The infected animals demonstrated mild clinical symptoms including fever. Two of the six infected monkeys developed fever (1.5 above the level before challenge) on the day 10 post inoculation (p.i.). Although the severe clinical symptoms or mortality were not observed, the virological and histopathological evidences of the illness were evident. The specimens collected from the infected animals showed the presence of SARS-CoV detected by RT-PCR, IFA, and by virus isolation. From the organs examined postmortem, a major pathological change was observed in the lungs. The walls of the alveoli were thicker, infiltrated with inflammation cells and an exudative fluid was found in the alveolar spaces. In addition, some alveolar spaces showed hyaline membrane lining. The results showed that the monkeys infected with SARS-CoV developed the typical SARS according to clinical, virological, and pathological findings.

First Report of Spinach latent virus in Tomato in New Zealand.

A Lycopersicon esculentum (tomato) plant from a commercial property in New Zealand was submitted to the Investigation and Diagnostic Centre for diagnosis in 2003. Fruits had faint yellow ringspots but no obvious symptoms were observed on leaves. No virus particles were observed from tomato and symptomatic herbaceous plants crude sap preparations. Mechanically inoculated Nicotiana clevelandii and N glutinosa developed systemic chlorosis, whereas pinpoint necrotic local lesions were observed on Chenopodium amaranticolor. Chlorotic local lesions were also observed on C. quinoa followed by systemic necrosis. No symptoms were observed on Cucumis sativus, Gomphrena globosa, N. benthamiana, N. sylvestris, or N. tabacum cv. White Burley. Total RNA was extracted from N. glutinosa and C. quinoa leaf samples using the Qiagen (Qiagen Inc., Valencia, CA) Plant RNeasy Kit. Reverse transcription (RT) was carried out by using random hexamer primers and SuperScript II reverse transcriptase (Invitrogen, Frederick, MD) followed with PCR using broad-detection primers targeting the genera Carmovirus, Dianthovirus, Ilarvirus, Tospovirus, (Agdia Inc., Elkhart, IN) and Tombusvirus (2). A positive RT-PCR amplification was obtained only with Ilarvirus primers. The 450-bp product (GenBank Accession No. DQ457000) from the replicase gene had a 97.4% nt and 98.6% aa identity with Spinach latent virus (SpLV; Accession No. NC_003808). An RT-PCR protocol was developed for the specific detection of SpLV. Primers were designed from three SpLV RNA sequences (RNA1: NC_003808; RNA2: NC_003809; RNA3: NC_003810) using the Primer3 software (3). Primers SpLV-RNA1-F (5'-TGTGGATTGGTGGTTGGA-3') and SpLV-RNA1-R (5'-CTTGCTTGAGGAGAGATGTTG-3') anneal to the replicase gene from nt 1720 to 2441. Primers SpLV-RNA2-F (5'-GAACCACCGAAACCGAAA-3') and SpLV-RNA2-R (5'-CCACCTCAACACCAGTCATAG-3') bind to the polymerase gene from nt 603 to 1038. Primers SpLV-RNA3-F (5'-GCCTTCATCTTTGCCTTTG-3') and SpLV-RNA3-R (5'-CATTTCATCTGCGGTGGT-3') amplify the movement protein gene from nt 724 to 936. The predicted amplified product sizes were 722, 436, and 213 bp from RNA1, RNA2, and RNA3, respectively. RT was carried out as described above. PCR was performed in a 20-µl reaction containing 2 µl cDNA, 1× Taq reaction buffer, 1.5 mM MgCl2, 0.2 mM dNTPs, 0.2 µM of forward and reverse primers, and 1 U Taq polymerase (Promega, Madison, WI). The PCR amplification cycle was identical for the three primer pairs: denaturation (95°C for 3 min) followed by 37 cycles of 95°C (20 s), 60°C (30 s), and 72°C (30 s) with a final elongation step (72°C for 3 min). The amplified products were analyzed by gel electrophoresis, stained with SYBR Green, and their identities confirmed by sequencing. The tomato sample was grown from seed imported from the Netherlands where SpLV occurs (4). The virus is of potential importance for the tomato industry because of its symptomless infection and high frequency of seed transmission in many plant species (1,4). SpLV has never been detected in other submitted tomato samples. Consequently, SpLV is not considered to be established in New Zealand. To our knowledge, this is the first report of SpLV in tomato. References: (1) L. Bos et al. Neth. J. Plant Pathol. 86:79, 1980. (2) R. Koeing et al. Arch. Virol. 149:1733, 2004. (3) S. Rozen and H. Skaletsky. Page 365 in: Bioinformatics Methods and Protocols. Humana Press, Totowa, NJ, 2000. (4) Z. Stefenac and M. Wrischer. Acta Bot. Croat. 42:1, 1983.

[Expression of human chorionic gonadotropin, human placental lactogen and pregnancy-specific 1-glycoprotein in malignant trophoblastic neoplasms].

The expression of placental hormones in 91 malignant trophoblastic neoplasms was studied immunohistochemically using a panel of antibodies against hCG, human placental lactogen (hPL) and pregnancy-specific 1-glycoprotein (SP). The results indicated that the expression of hCG in invasive moles was weaker than that in choriocarcinoma, but the expression of hPL and SP1 was stronger than those in choriocarcinoma. The expression of hPL and SP1 in the metastatic tumors of invasive moles was weaker than the expression at in the primary tumors, but the secretory capacity of hCG in metastatic choriocarcinomas was stronger than that in the primary neoplasms. In this study, the qualities of expression of the placental hormones in invasive moles and choriocarcinomas corresponded to the degree of tumor malignancy, the biological behaviour and the grading of trophoblastic cell differentiation. We believe that the detection of hCG, hPL and SP1, in malignant trophoblastic neoplasms was of value for establishing tumor diagnosis and typing and for judgement on prognosis.

[A combined staining of immunohistochemistry and in situ hybridization for detecting epidemic hemorrhagic fever virus in tissue section].

A combined staining of immunohistochemistry and in situ hybridization has been successfully applied to detect antigen and viral RNA at the same tissue slice from epidemic hemorrhagic fever (EHF) autopsy. Multiple McAb were used to detect EHFV antigen, followed with a digoxigenin-labelling cDNA probe for detecting EHFV RNA respectively. The viral antigen was seen in the cellular cytoplasm and viral RNA was demonstrated within the nuclei. It is emphasized that pretreatment of the section with Lugol's solution and choice of suitable proteolytic enzyme as well as proper temperature and time for the hybridization are the key points for the staining.

[Alterations in insulin receptor in injured rats and the effects of dexamethasone and silybin].

The purpose of this study is to examine the alterations in hepatocyte insulin receptors in rats subjected to scald and restrained water immersion stress and the effects of dexamethasone and silybin. In scalded rats, plasma glucose and insulin levels were higher than that of normal rats, suggesting the occurrence of insulin resistance following injury. The maximal binding capacity (Ro) and highest insulin binding rate (Bo/T) of hepatocyte insulin receptors were significantly reduced in rats 72h postscalding, while there was no obvious change in affinity (Ke Kf). The Ro and Bo/T of the restrained water immersion stress rats were also reduced significantly, but the affinity was increased. Dexamethasone significantly enhanced Ro in rats 72h postscalding with significant decrease in affinity (Ke). Silybin significantly enhanced Ro and Bo/T 72h postscalding with no obvious change in affinity. It is suggested that insulin resistance following injury may be a consequence of receptor defect of the target cells, and for disturbance of glucose metabolism following injury, it is not beneficial to use dexamethasone, but silybin may be used with benefit.

Characteristics of different isolates of Schistosoma japonicum from China in the final hosts.

The present paper deals with the susceptibility of common laboratory animals, such as mouse, rat, hamster, jird, rabbit and rhesus monkey, to infection with different isolates of Schistosoma japonicum in the mainland of China under laboratory conditions. With the exception of the rat, all the animals under study were permissive hosts for different isolates though their worm recovery rates varied. The mean body length of pair-worms of the Yunnan isolate was considerably smaller than that of the Anhui, Hubei, Guangxi and Sichuan isolates, and the percentage of male specimens with 7 testes in the Yunnan isolate was also significantly less than that in the other 4 isolates. Judging from the egg index (width/length x 100), the eggs of the Sichuan isolate were broad and short in shape, giving a high index; those of Guangxi and Hubei isolates were oblong, giving the lowest index; the other two isolates from Yunnan and Anhui, lay between these two extremes. The mean prepatent periods were longer in mice, hamsters and rhesus monkeys infected with Yunnan and Guangxi isolates, than those with Sichuan isolate. A dendrogram of the 5 isolates of S. japonicum was constructed on the basis of similarity coefficients by means of fuzzy cluster analysis on the biological characters mentioned above. Our results provide evidence of the existence of different strains of S. japonicum in the mainland of China as shown by comparative studies of their characteristics in the final hosts.

Studies on bioactive components from Chinese medicinal plants.

Several novel bioactive components isolated from Chinese medicinal plants will be presented. These include novel maytansinoid tumor inhibitors, some new ent-kaurane and rosane diterpenoids from Mallotus anomalus Meer et Chun (Euphorbiaceae), as well as novel insecticide, stemona alkaloids from Stemona parviflora C. H. Wright (Stemonaceae). Both are native plants of Hainan island, China. 2D NMR techniques such as mono and hetero-COSY, NOESY, COLOC as well as 1H-NMR line broadening effect were utilized for structure elucidation. The separation techniques, structure elucidations and bioassay results will be reported.

[Studies on the strain differences of Schistosoma japonicum in the mainland of China. IV. Fuzzy cluster analysis on some biological characters of different isolates of Schistosoma japonicum].

In this paper, a computerized numerical systematics was used to analyse the 5 different isolates of Schistosoma japonicum in the mainland of China by means of fuzzy clustering method with 32 quantitative data of each isolate about the morphological and biological characters. A dendrogram of the 5 isolates of S. japonicum was constructed on the basis of similarity coefficients as shown. The phylogenetic relationships revealed by the present study show that the two isolates of Anhui and Hubei get together firstly in one group, then the isolates of both Yunnan and Guangxi gather in another group, while the Sichuan isolate is closely related to the group of Anhui-Hubei isolates, not to the Yunnan ones, although both Sichuan and Yunnan isolates were in the southwest China.

[Studies on the strain differences of Schistosoma japonicum in the mainland of China. III. Morphometric data].

The present investigation was undertaken to determine whether differences exist in the size of cercariae, adult worms and eggs among different isolates of S. japonicum in the mainland of China. Measurements on the corresponding stages of Japanese and Philippine strains of S. japonicum were also carried out for comparison. The size of cercariae collected from pooled naturally infected snails from different isolates was shown in Table 1. The body index of Yunnan isolate, which is defined as cercaria length x width (mm) x 1,000, was found to be smaller than those of the other 4 isolates, this difference being significant at p less than 0.01. Measurements of adult worms and eggs from different isolates were taken from various hosts infected with the same number of cercariae and for the same duration of infection. Results indicated that the mean length of mature worms and the size of mature eggs varied not only in different host species but also among host individuals of the same species infected with the same isolate of parasite. The mean length of mature worms of S. japonicum from various hosts infected with Yunnan isolate was considerably smaller than those of the other 4 isolates (Table 2), this difference being significant at p less than 0.05 by analysis of variance. Regarding the size (length x width) of eggs in mice and hamsters, large size eggs were found from both Yunnan and Guangxi isolates, while in rabbits and rhesus monkeys, large size eggs were found from Sichuan parasites.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of albendazole and pyrantel in treating intestinal helminthiasis and controlling the recurrence of hookworm infections].

A total of 720 human intestinal helminthic infections were divided into 4 groups and treated with albendazole 400mg/d x 3d, 400mg/d x 5d, pyrantel 1,500mg/d x 3d, or 1,500mg/d x 5d. Half a month after treatment, the negative rates of hookworm egg were 98.6, 98.6, 86.2 and 93.5%, those of ascaris egg were 96.5, 98.2, 92.9 and 96.3%, and those of whipworm egg were 86.4, 89.0, 68.9 and 67.0% respectively. Reduction rate of hookworm egg reached more than 98% in all the 4 groups. Six months after treatment, however, the positive rates of all the 4 groups rose again in varying degrees. The predominant species of hookworm infections was Necator americanus before the treatment and Ancylostoma duodenale after the treatment. It was demonstrated that the recurrence of hookworm infection resulted from A. duodenale infections, while a single dose of 400mg albendazole per day for 3 or 5 days showed good effect in controlling the recurrence of hookworm infections in a certain area.

Modified immunodiffusion and peroxidase staining methods to detect Escherichia coli nitrite reductase and other sirohaem-containing proteins.

A rapid, sensitive and stable staining procedure is described which has allowed the peroxidase activity associated with the sirohaem-containing NADH-dependent nitrite reductase from Escherichia coli to be detected. Sirohaem is rapidly lost from this enzyme, so conventional one- or two-dimensional immunoelectrophoresis techniques were modified to permit the detection of residual sirohaem associated with the protein. Reconstitution experiments established that a sirohaem-rich fraction from a nitrite reductase-deficient mutant could reactivate partially purified nitrite reductase eluted from a chromatography column. We suggest that the techniques described could readily be modified to detect immunoprecipitates containing other labile enzymes for which there is a specific activity stain, or for other proteins with an associated peroxidase activity.