Advance in receptor type protein tyrosine phosphatase Q

Receptor type protein tyrosine phosphatase Q (PTPRQ) is an unusual protein tyrosine phosphatase that has intrinsic dephosphorylating activity for various phosphatidylinositiol and phospho-tyrosine substrates, especially the phosphatidylinositol activity. Recent data show that PTPRQ has an important role in various biological processes and is associated with some diseases. In this article, the structure and function of PTPRQ and the relationship between PTPRQ and diseases were briefly summarized.     

Effect of transfection of tumor necrosis factor α gene and its mutants on tumorigenicity of H22 tumor cells in vivo

AIM: To compare the tumorigenecity of H22 cells transfected with TNF-α gene and its mutants(secreted TNF-α mutant, S-TNF^m, transmembrane TNF-α mutant, TM-TNF^m and wild type of TNF-α, Wt-TNF) in vivo. METHODS: Three kinds of mouse liver cancer cell line H22 expressing TNF-α and its two mutants were mixed with untransfected H22 at different effector/target ratio separately. The growth of tumor was examined after injection of 2.5×10⁵(100 μL) mixed H22 tumor cells into mice. The lymphocyte infiltration in the site of tumor and the expression of Fas on tumor cells were detected by immunohistochemistry. RESULTS: The tumorigenecity of H22 cells transfected with TNF-α gene and its mutants was significantly weakened( P <0.01). Besides the cytotoxicity of the both forms of TNF, TM-TNF was found to induce the expression of death receptor Fas by tumor cells and S-TNF was shown to promote frank lymphocyte infiltration in the site of tumor. Furthermore, a transient decrease in body weight was found in mice inoculated with H22/S-TNF^m. CONCLUSION: The tumorigenecity of tumor cells was reduced by transfection with TM-TNF or S-TNF gene. It results from the cytotoxicity of TNF and their activation of tumorcidal mechanisms in vivo. TM-TNF may induce tumor cell apoptosis via the Fas pathway while S-TNF may exert its antitumor effect by recruiting and activating lymphocytes in the site of tumor.     

Mortality,morbidity, and external injuries in piglets housed in two different housing systems

An investigation was undertaken to study two different types of farrowing pens, use being made of well characterized veterinary parameters for the well‐being of piglets. A housing system with a solid floor and straw‐bedding was compared with a partly metal‐slatted floor system. The veterinary parameters we used were mortality, morbidity, and external injuries in piglets. There were slight differences in mortality and morbidity rates between the two housing systems. There were big differences with regard tp the piglets” injury‐index’ of the two housing systems. The straw system was more favourable. The studies show that obervations of external injuries ('Method of Ekesbo') can be used to judge housing systems of piglets in the farrowing house.     

Isoenzyme studies on Theileria (Protozoa,Sporozoa). Enzyme activity associated with the erythrocytic stage

Summary

Bovine blood containing piroplasms of Theileria parva, as well as non‐injected blood, was lysed and subjected to iso‐electric focussing.

Staining for 13 different enzymes revealed parasite‐associated bands of glucose phosphate isomerase (GPI) activity, not of any of the other enzymes. There were no variations between individual donor animals in the host cell GPI bands and these bands did not interfere with the recognition of the parasite‐associated bands, so that purification of the piroplasms was unnecessary. Blood from cattle infected with T. mutans also gave parasite‐associated bands of GPI, but no such bands were seen in zymograms of blood from cattle infected with a Theileria sp. from Japan. Depending on the level of parasitaemia, up to four parasite‐associated bands were found in one strain of T. parva and up to three in two other strains. Among the disadvantages of using piroplasm material for the study of isoenzymes of T. parva is the fact that animals often die before their parasitaemia is sufficiently high, and that some strains never give rise to a high parasitaemia.     

Progresses on antitumor effect of snake venom active components

Many snake venoms contain complex mixtures of pharmacologically important molecules, some of which show potential therapeutic value in the treatment of cancer and other human disorders. In this review, we mainly reports the effects of snake venom active components, such as disintegrins and lectins in paralyzing cancer cells, blocking on cell migration, interaction with integrins, inhibition of tumor dissemination and angiogenesis. The advanced researches on the snake venom's apoptosis-inducing components on tumors are also introduced.     

Advances in endostatin research

Endostatin, a 20 kD (184 aa) C-teminal fragment of collagenⅩⅧ, is the most potent inhibitor of tumor angiogenesis described so for. Endostatin was initially isolated from a murine hemangioendothelioma cell line (EOMA). Purified recombinant murine endostatin generated in E. coli bacteria injected as unfolded suspension, inhibited the growth of a varity of metastatic and primary tumors in mice. However, its widespread application has been hampered by difficulties in the large-scale production of the antiangiogenic proteins. The limitation may be resolved by in vivo delivery and expression of the antitangiogenic gene. This review summarized the advances in endostain research in recent years including structure, the mechanism of generating, function and therapy.     

Experimental study of 5-fluorouracil loaded polylactic acid nanoparticles control-releasing preparation on tumor

AIM: To investigate the preparation techniques and anti-tumor effects both in vitro and in vivo of a novel nanoparticles control-releasing preparation of 5-fluorouracil (5-FU) by intravenous injection.METHODS: With polylactic acid (PLA) as marix materials,we adopted ultrasound emulsification method to prepare PLA enveloped 5-FU nanoparticles (5-FU-NPs).Scanning electricity microscopy was used to observe the morphology of 5-FU-NPs and laser optical scattering experiment was conducted to determine its diameter distribution.The drug-carrying capacity (ratio) of the nanoparticles was determined by means of high-power liquid chromatography(HPLC) and MTT test was used to observe cytotoxicity in vitro.The anti-tumor effects were determined at different dosages,frequencies of taking drugs in vivo.RESULTS: Scanning electron microscopy showed that the 5-FU-NPs were globular particles with smooth surface in an average particle diameter of 191.9 nm with a normal distribution,and the drug-carrying capacity of 5-FU-NPs was 15.2%.5-FU-NPs had the same anti-cancer effect as unenveloped drug in vitro and showed typical dose-effect relationship.Compared to naked 5-FU,5-FU-NPs presented significant difference (P<0.05) in anti-cancer effect.CONCLUSION: Nanoparticles may serve as effective carrier for controlled release of 5-FU,which lead to reasonable administration of 5-FU with less toxicity.     

A hereditary disposition for bovine peripheral nerve sheath tumors in Danish Holstein cattle

Background

Peripheral nerve sheath tumors (PNSTs) are frequently found in Danish cattle at slaughter. Bovine PNSTs share several gross and histopathological characteristics with the PNSTs in humans with heritable neurofibromatosis syndromes. The aim of the present study was to investigate a possible hereditary disposition to PNSTs in dairy cattle by statistical analysis performed on data from 567 cattle with PNSTs. Furthermore, a preliminary genome-wide association study (GWAS) was performed on DNA isolated from 28 affected and 28 non-affected Holstein cows to identify loci in the bovine genome involved in the development of PNSTs.

Results

PNSTs were significantly more common in the Danish Holstein breed than in other breeds with 0.49% of Danish Holsteins slaughtered during an eight-year-period having PNSTs. PNSTs also occurred significantly more frequently in the offspring of some specific Holstein sires. Examination of three generation pedigrees showed that these sires were genetically related through a widely used US Holstein sire. The PNSTs included in GWAS were histologically classified as neurofibroma-schwannoma (43%), schwannoma (36%) and neurofibroma (21%) and derived from Holstein cows with multiple PNSTs. A single SNP on chromosome 27 reached genome-wide significance.

Conclusions

Gross and histological characteristics of bovine PNSTs are comparable to PNSTs in humans (schwannomatosis). Danish Holsteins are genetically disposed to develop PNSTs but the examined materials are insufficient to allow determination of the mode of inheritance.