[Analysis of the influence of iron overload in glucose metabolism in thalassemia major patients]

Objective: This study aimed at determining the characteristics of the glucose homeostasis and its relationship with iron overload of the patients with β-thalassemia major (β-TM). Method: From Sun Yat-sen Memorial Hospital between January 2014 and December 2015, a total of 57 transfusion-dependent β-TM patients with 5-18 years old were enrolled in this study and fasting blood glucose(FBG) and insulin level, serum ferritin (SF), serum iron, transferrin, total iron binding capacity, unsaturated iron binding capacity were determined.Insulin resistance index (IRI), insulin sensitivity index and β-cell function index (BFI) were also estimated. Besides, in 36 patients cardiac T2* and liver T2* were estimated. Result: (1) Four patients(7%) with β-TM were diagnosed diabetes mellitus, and 14(24%) had impaired fasting glucose. (2) The incidence of abnormal glucose metabolism was significantly different according to levels of SF and degrees of the cardiac iron overload(χ(2)=9.737, P<0.05; χ(2)=17.027, P<0.05). It rose while the level of SF increased and the degree of cardiac iron overload aggravated. (3) The incidence of abnormal glucose level was not significantly different in cases with different degree of liver iron overload.The severe group of liver iron overload had significantly higher levels of INS, HOMA-βFI, HOMA-ISI, HOMA-βFI than the non-severe group (Z=-2.434, -2.515, F=8.658, all P<0.05), while no differences were found in the level of FBG, HOMA-βFI between two groups. (4) The result of logistic regression analysis indicated that the cardiac T2* was a significant predictor for the incidence of abnormal glucose metabolism in TM patients (P=0.035, OR=1.182%, 95%CI=1.048 to 1.332). Conclusion: The high prevalence of abnormal glucose metabolism in β-TM patients was mainly closely related with the internal iron overload, especially in organs.The cardiac T2* was an independent risk factor for the incidence of abnormal glucose metabolism in TM patients.

[Genetic instability in cancer tissues analyzed by RAPD PCR]

In five kinds of tumors, total 128 specimens were analyzed by RAPD (random amplified polymorphic DNA) PCR with nine 10-base arbitrary primers for detecting instabilities of DNA and chromosome and screening new molecular markers coupled to putative or unknown oncogenes and/or tumor suppressor genes. Bands representing instabilities have been recovered and purified from agarose and cloned into pCAPs vector, and further labeled by DIG as probes for analysis of Southern blot, Northern blot and Sequencing. Results revealed that sample 5 and 3 of the gastric cancers showed the highest genomic changes and the average detectability in five sorts of cancers was up to at least 40% (42.2%-49.4%), and that there were significant differences in the ability of each primer to detect genomic instability, which ranged from 27% to 68%. Despite the highest detectability of genetic instability (68%) in tumor tissues, primer 2 could produce stable profiles of DNA bands in normal tissue genome with good reproducibility. On the contrary, primer 8 was of the lowest one (27%). Band B of single copy found to be allelic losses in gastric and colon cancers according to RFLP analysis was of a novel sequence and registered by Gen-Bank (Accession Number AF151005). Therefore the genetic instabilities often concentrated on some special locuses of chromosome e.g. repetitive sequences etc. and coupled to carcinogenesis. It was impossible or difficult to get great achievements for cancer treatments with the procedure of gene therapy only to one oncogene or one tumor suppressor gene because the extensive DNA variations occurred during the progression of tumor. RAPD assay connected with other techniques was a good tool for the detection of genomic instabilities and direct screening of some new molecular markers related to tumor suppressor genes or oncogenes.

[Infection of mutated mouse complement receptor type II by Epstein-Barr virus]

Site-directed mutagenesis method was used to introduce two desired mutations, which were confirmed by DNA sequencing, into mouse complement receptor Type II gene(MCR2). Then the constructed eukaryotic expression vectors containing wild type mouse CR2/1(wtMCR2/1), mutant type mouse CR2/1 (mtMCR2/1) and human CR2 (hCR2) cDNA were transferred into mouse SP2/0 cells by electroporation. After two-week screening by G418, the stably transfected clones were obtained. Several ways including PCR, RT-PCR, and immunohistochemistry were utilized to screen those clones with interesting genes integrated and expressed. Then Epstein-Barr virus(EBV) was used to infect these transfected cells and EBER-1 (EBV encoded RNAs) hybridization results showed that only hCR2 and mtMCR2 transfected SP2/0 cells could be infected by EBV, but positive rate of the former was much higher than the latter. This study sets groundwork for elucidating the mechanism by which EBV enters the cells and for establishing the animal model of EBV-related nasopharyngeal carcinoma (NPC).

[Study on the molecular structure and function of protein kinase C isoenzyme]

Protein kinase C (PKC) is a serine/threonine kinase family consisting at least 11 related isoenzymes, and it can be divided into four distinct classes, conventional PKC (cPKCs), novel or new PKC (nPKCs), atypical PKC (aPKCs), and PKC-u. All PKC members contain conserved and variant amino acid sequences in ATP binding sites, phosporyl transfer region, pseudosubstrate region, and phorbol ester binding sites. PKC isoenzymes exhibit distinct tissue distribution and play a critical role in cellular events. This review mainly summarized the PKC effects on tumorigenesis, tumor invasion and metastasis, tumor multidrug resistance, differentiation and development of hematopoietic progenitor cells, and hormonal production and secretion.

[Hemodynamics in skin and tissue expansion]

The capillary blood flow (CBF) of the random flaps constructed on expanded and unexpanded skin of dogs was determined by radioactive microsphere technique. The CBF was significantly higher (P < 0.001) in the skin flaps of the expanded group (387 +/- 23 microliters/min/flap) than that of the acute group (127 +/- 16 microliters/min/flap). There were no significant differences in the expanded group, the delayed group (374 +/- 35 microliters/min/flap) and the control group (389 +/- 48 microliters/min/flap). Even at the pedicle site, the CBF of the acute group was already significantly lower than that of other three groups (P < 0.001). The general tendency of gradual CBF reduction from the pedicle to the distal end of all the flaps was observed. The CBF at the point 8cm from the pedicle of the acute group was 12 microliters/min/g, whereas in other three groups, at point 13 cm from the pedicle the CBF was 12 microliters/min/g. The results suggested that during skin expansion the area of skin is enlarged, and its CBF and survival length may be increased. The problem of capsulectomy during flap construction was discussed.