Endothelial apoptotic activity of angiocidin is dependent on its polyubiquitin binding activity

We recently cloned the full-length cDNA of a tumour-associated protein. The recombinant protein expressed in bacteria and referred to as angiocidin has potent antitumour activity in vivo and in vitro. Angiocidin inhibits tumour growth and angiogenesis by inducing apoptosis in endothelial cells. Based on the sequence similarity of angiocidin to S5a, one of the major polyubiquitin recognition proteins in eukaryotic cells, we postulated that the antiendothelial activity of angiocidin could be due in part to its polyubiquitin binding activity. In support of this hypothesis, we show that angiocidin binds polyubiquitin in vivo with high affinity and colocalises with ubiquitinated proteins on the surface of endothelial cells. Binding is blocked with an antiubiquitin antibody. Angiocidin treatment of endothelial cells transfected with a proteasome fluorescent reporter protein showed a dose-dependent inhibition of proteasome activity and accumulation of polyubiquitinated proteins. Full-length angiocidin bound polyubiquitin while three angiocidin recombinant proteins whose putative polyubiquitin binding sites were mutated either failed to bind polyubiquitin or had significantly diminished binding activity. The in vitro apoptotic activity of these mutants correlated with their polyubiquitin binding activity. These data strongly argue that the apoptotic activity of angiocidin is dependent on its polyubiquitin binding activity.

Translocation of GPIb and Fc receptor gamma-chain to cytoskeleton in mucetin-activated platelets

Recent studies have implied that GPIb-IX-V as well as functioning as an adhesion receptor may also induce signaling to mediate binding of platelets to damaged vessel wall to prevent bleeding. Reorganization of the cytoskeleton and redistribution of platelet structural proteins and signaling molecules are thought to be important in this early activation process, though the molecular mechanisms remain to be fully defined. In this study, we have used mucetin, a snake venom lectin protein that activates platelets via GPIb, to study the redistribution of GPIb in platelets. In unstimulated platelets, a minor portion of GPIb localized to Triton-insoluble cytoskeleton fractions (TIC). This portion increased considerably after platelet activation by mucetin. We also find increased contents of the FcRgamma chain in TIC. Anti-GPIb antibodies, mocarhagin or cytochalasin D completely inhibited the cytoskeletal translocation. In addition, BAPTA-AM, a cytoplasmic calcium chelator, strongly inhibited this process. On the other hand, inhibitors of alphaIIbbeta3, PLCgamma, PKC, tyrosine kinases, ADP receptor, PI3-kinase or EDTA are effective in preventing GPIb relocation in convulxin- but not in mucetin-activated platelets. We propose that cytoskeletal translocation of GPIb is upstream of alphaIIbbeta3 activation and cross-linking of GPIb is sufficient to induce this event in mucetin-activated platelets.

Molecular cloning of a cDNA encoding a putative cuticle collagen of Trichinella spiralis

A 5-day-old adult stage-specific cDNA fragment from Trichinella spiralis was identified by suppression subtractive hybridization and was used as a probe to screen the cDNA library. The cDNA sequence coding for a putative T. spiralis cuticle collagen was isolated. The cDNA encoded an open reading frame of 343 amino acid residues with molecular weight of 35.1 k Da. The deduced protein contained an N-terminal signal peptide, a nematode cuticle collagen N-terminal domain and a collagen triple helix repeat domain. Searches in GenBank using BLASTP showed up to 47% identity to cuticle collagens from other nematodes. Southern blot analysis of genomic DNA indicated this gene was present as a single copy in T. spiralis genome.

Snake venoms and hemostasis

Snake venoms are complex mixtures of biologically active proteins and peptides. Many of them affect hemostasis by activating or inhibiting coagulant factors or platelets, or by disrupting endothelium. Based on sequence, these snake venom components have been classified into various families, such as serine proteases, metalloproteinases, C-type lectins, disintegrins and phospholipases. The various members of a particular family act selectively on different blood coagulation factors, blood cells or tissues. For almost every factor involved in coagulation or fibrinolysis there is a venom protein that can activate or inactivate it. Venom proteins affect platelet function by binding or degrading vWF or platelet receptors, activating protease-activated receptors or modulating ADP release and thromboxane A2 formation. Some venom enzymes cleave key basement membrane components and directly affect capillary blood vessels to cause hemorrhaging. L-Amino acid oxidases activate platelets via H2O2 production.

Localization of pms3, a gene for photoperiod-sensitive genic male sterility, to a 28.4-kb DNA fragment

Photoperiod-sensitive genic male-sterile (PSGMS) rice, in which pollen fertility is regulated by day-length, originally arose as a natural mutant in the rice cultivar Nongken 58 (Oryza sativa ssp. japonica). Previous studies identified pms3 on chromosome 12 as the locus of the original PSGMS mutation. In this study we have assigned the pms3 locus to a 28.4-kb DNA fragment by genetic and physical mapping. A cross between Nongken 58S (PSGMS line) and DH80 was used to produce an F2 population of about 7000 plants, from which 892 highly sterile individuals were obtained for recombination analysis. By analyzing recombination events in the sterile individuals using a total of 157 RFLP probes from a BAC contig covering the pms3 region, the pms3 locus was localized to a sub-region of less than 1.7 cM. Further analysis of recombination events using 49 additional probes isolated from this sub-region identified markers flanking the pms3 region on each side; these markers are only 28.4-kb apart. Sequence analysis of this fragment predicted the presence of five ORFs, found high homology with two ESTs in public databases, and detected three SNPs between the mutant and the wild-type parents, which may be helpful for identifying a candidate gene for pms3.

Study on the haplotypes of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population

The purpose of this study was to investigate the genetic polymorphisms and haplotypes of microsatellite locus in exon 5 of the MICA gene and intron 1 of the MICB gene and human leukocyte antigen-B (HLA-B) gene based on 106 samples of the Guangzhou Han population through means of polymerase chain reaction and the fluorescent technique (6-FAM). The corresponding haplotype frequencies, linkage disequilibrium values and relative linkage disequilibrium values were estimated based on population data. The results show that the genotype distributions of MICA and MICB microsatellite and HLA-B satisfy the Hardy-Weinberg equilibrium. In total, five alleles of MICA microsatellite locus and 14 alleles of MICB microsatellite locus were observed. MICA A5 was the most common allele (0.2877), whereas A4 was the least common (0.1321). MICB CA14 was the most common allele (0.3255), and CA19 and CA28 were the two least common (0.0047). CA27 was not observed at all. Five kinds of MICA-MICB haplotypes, 18 kinds of MICA-HLA-B haplotypes and 12 kinds of MICB-HLA-B haplotypes occurred at frequencies of more than 1%. The common haplotypes of MICA-MICB, MICA-HLA-B and MICB-HLA-B were A5-CA14, A5.1-CA18, A4-CA26, A9-CA15, A5-B*15(62), A5.1-B*1301/1302, A4-B*1301/1302, A6-B*51, A6-B*4403, A9-B*3802, CA14-B*4601, CA18-B*1301/1302 and CA26-B*1301/1302, and these haplotypes showed strong linkage disequilibrium. The polymorphisms and haplotype distributions of MICA and MICB microsatellite and HLA-B locus in the Guangzhou Han population have their own distinct genetic characteristics. The microsatellite locus of exon 5 of the MICA gene and intron 1 of the MICB gene could therefore be used as genetic markers in the studies of anthropology, gene linkage analysis in genetic diseases, individual identification and paternity testing in forensic medicine.

Exercise training increases the näive to memory T cell ratio in old mice

Aging is associated with changes in T cells including involution of the thymus gland and an imbalance in the proportion of näive (CD44lo) and memory (CD44hi) T cells in the periphery. Reversal of these changes may improve immunity in the aged. We sought to determine whether 4 months of moderately intense treadmill running (EXC; 5 days/week, 45 min/day, 13-22 m/min) in 2 month (Y) and 18 month (O) old male Balb/c mice would alter T lymphocyte profiles in the thymus and spleen when compared to sedentary controls (CON). Splenocytes and thymocytes were harvested 24-48 h after the last exercise session and analyzed using immunofluorescence and flow cytometry. While there were significant age-related changes (lower cell number, altered subsets) in the thymuses of O when compared to Y mice, exercise training failed to affect any of these measures in mice of either age. Aged mice exhibited a significantly (p < .05) higher percentage of splenic memory cells and a lower percentage of näive cells in both the CD4 and CD8 T cell subsets. Interestingly, exercise training significantly (p < .05) increased the percentage of näive and decreased the percentage of memory cells in both the CD4+ (69.6+/-1.7% näive and 30.4+/-1.7% memory for OCON vs. 75.0+/-1.5% näive and 25.0+/-1.5% memory in OEXC) and CD8+ (60.0+/-2.6% näive and 40.0+/-2.6% memory in OCON vs. 76.7+/-2.7% näive and 23.3+/-2.7% memory in OEXC) T cells subsets in O, but not Y, mice. This effect was due to a decrease in the absolute number of memory cells and not an increase in the absolute number of näive cells. We conclude that 4 months of EXC has little restorative effect on the thymus in aged mice, but can restore the percentages of näive and memory cells in the spleen towards that of young mice, perhaps due to removal of memory cells.

Mechanisms of suppression of neoplastic transformation in vitro by low doses of low LET radiation

Suppression of neoplastic transformation of HeLa x skin fibroblast human hybrid cells in vitro following low doses of low linear energy transfer radiation has been reported previously. The present study represents an exploration of two hypothesized mechanisms that may underlie this observed suppression. These are the up-regulation of reduced glutathione (GSH), a known antioxidant, and induction of DNA repair activity. The hybrid cells were found to have a high endogenous level of GSH and no induction following low doses of 60 kVp X-rays was observed. Buthionine sulfoximine (BSO), a GSH biosynthesis inhibitor, completely suppressed GSH levels in both unirradiated and irradiated cells. Furthermore, there was no significant impact of BSO-induced suppression of GSH on the neoplastic transformation frequency of either unirradiated or low dose irradiated cells indicating that glutathione levels play no role in the low dose suppression of transformation frequency. To assess the possible role of DNA repair in the low dose suppression of transformation the effect of 3-aminobenzamide (3-AB), a poly-ADP-ribose polymerase (PARP) inhibitor was examined. In these experiments, there was no significant effect of 3-AB on the transformation frequency at a dose of Cs-137 gamma rays of 0.5 cGy, however, at a dose of 5 cGy there was a significant increase (P < 0.05) in the transformation frequency in the presence of 3-AB. These findings suggest that the influence of DNA repair on the low dose suppression of transformation is significant at a dose of 5 cGy, but not at the lower dose of 0.5 cGy.

Pressure/volume curves and lung computed tomography in acute respiratory distress syndrome

Pressure/volume (P/V) curves can be measured by static methods, constant or sinusoidal flow methods and the dynostatic method that allows a breath-to-breath determination of P/V curves. Recent ventilators are equipped with specific flow generators and software aimed at obtaining P/V curves without disconnecting the patient from the ventilator. The most recent generation of computed tomography scanners allows the quantitative determination of lung aeration, lung volumes (gas and tissue), alveolar recruitment and lung overinflation of the whole lung. In the supine position, the acute respiratory distress syndrome (ARDS) lung is characterised by an increase in lung tissue that predominates in upper lobes and a massive loss of aeration that predominates in lower lobes. In a minority of ARDS patients, the loss of aeration is homogeneously distributed. The overall lung volume of upper lobes is preserved suggesting an alveolar flooding-induced loss of aeration. In contrast, the overall lung volume of lower lobes is reduced because the heart and the abdomen exert an external compression that contributes to the loss of aeration. The P/V curve is a lung recruitment curve and the chord compliance indicates the potential for recruitment. In such patients, alveolar recruitment resulting from positive end-expiratory pressure is not accompanied by lung overinflation. In a majority of acute respiratory distress syndrome patients, upper lobes remain partially or totally aerated despite a marked regional increase in lung tissue. The upper lobes' overall lung volume is either normal or increased, suggesting that the lung does not collapse under its own weight as generally believed. In lower lobes, the overall lung volume is reduced because the heart and the abdomen exert an external compression that contributes to the loss of aeration. The pressure/volume curve is influenced by the recruitment of poorly and nonaerated lung regions and by the mechanical properties of the part of the lung remaining aerated. In such patients, alveolar recruitment resulting from positive end-expiratory pressure >10 cmH2O is preceded and accompanied by lung overinflation.

Post-occlusive reactive hyperemia in single nutritive capillaries of the nail fold: methodological considerations

Endothelial function at the arterial level has been extensively assessed by a non-invasive method using flow-mediated dilatation (FMD) of the brachial artery. Early disturbances have been found in patient groups prone to later development of manifest macrovascular atherosclerosis. A possible non-invasive means of studying blood-flow regulation and function at the microcirculatory level is through videophotometric capillaroscopy. The most stable variable in such an investigation is the time-to-peak (TtP) flow after a brief arterial occlusion. The short-term reproducibility of such assessments is excellent but the coefficient of variation (CV) in long-term studies is reported to be in the order of slightly less than 20%. The aim of the present methodological study was to evaluate different sources of variations in such microcirculatory assessments in order to be able to propose design recommendations that minimize the number of patients and recordings needed to achieve sufficient statistical power in longitudinal studies. We used a symmetric design with 144 recordings of TtP after a one-minute arterial occlusion in healthy volunteers. We did six occlusions each time in the capillaries of two fingers on each occasion, and repeated the procedure three times with an interval of at least one week between each investigation. All recordings were analyzed off-line using a cross-correlation technique with the Capiflow system. Each analysis was performed at least three times, giving a total of slightly less than 500 assessments. In our material (n = 10) TtP had a mean of 6.3 s (95% confidence interval 5.2-7.4). The correlation between repeated measurements in a single capillary during a single session was r > 0.91 (CV 6%). The between-finger CV was 8% (r = 0.84). The CV of measurements between different days was about 20% when single measurements were compared. However, the CV decreased to less than 13% when the mean of at least two time-to-peak assessments on each occasion was used. In conclusion, the methodological error including day-to-day variation could be minimized using the mean of at least two repeated assessments of post-occlusive hyperemia at each time point in a longitudinal study. This finding should be taken into consideration in the design of future longitudinal studies.

The female gender protects against pulmonary injury after trauma hemorrhagic shock

BACKGROUND

Previously, we have documented that lung injury after trauma-hemorrhagic shock (T/HS) is related to gut injury and that females are more resistant to T/HS-induced lung injury than males. However, it is not known if the estrus cycle stage at the time of injury influences the female rat's resistance to T/HS-induced lung injury. Therefore, the goal of this study was to determine if the protective effect of the female gender on lung injury after T/HS is estrus cycle stage-specific. To test this hypothesis, female rats were subjected to trauma (laparotomy) and hemorrhagic shock (T/HS) during different stages of the estrus cycle. Female animals subjected to trauma with sham hemorrhagic shock served as the control.

METHODS

Female Sprague-Dawley rats during the proestrus, estrus, metestrus, or diestrus stages of the menstrual cycle were subjected to a midline laparotomy (trauma) and either hemorrhagic shock (MAP = 30 mm Hg x 90 min) or sham shock. The total volume of blood necessary to induce and maintain the shock state was recorded. At the end of the shock period, the animals were resuscitated with their shed blood. At 6 h postresuscitation, the animals were sacrificed and lung permeability was measured using the Evans blue dye technique and by determining the bronchoalveolar (BALF) to plasma protein ratio. Additionally, pulmonary leukosequestration was quantitated by measuring pulmonary myeloperoxidase levels.

RESULTS

T/HS-induced lung injury and increased pulmonary leukosequestration were not observed in female rats in the proestrus or estrus stages of the menstrual cycle. In contrast, pulmonary permeability was increased significantly in the diestrus stage animals after T/HS. That is, the diestrus females subjected to T/HS had increased pulmonary permeability to Evans blue dye than sham or T/HS proestrus, estrus, and metestrus rats (6.49 +/- 1.33% versus 1.7 +/- 0.87%, 1.57 +/- 0.54%, 1.78 +/- 0.82%, 3.33 +/- 0.68%, p < 0.01, respectively). Similar results were obtained with the BALF protein/plasma protein ratio (0.15 +/- 0.017 versus 0.09 +/- 0.009, 0.09 +/- 0.03, 0.08 +/- 0.022, 0.11 +/- 0.029 p < 0.05, respectively). Although the T/HS metestrus rats had mildly increased lung permeability, this increase in T/HS-lung permeability did not reach statistical significance. Pulmonary myeloperoxidase levels after T/HS displayed a similar trend, with diestrus rats subjected to T/HS having the highest level of MPO (p < 0.05 versus sham or T/HS proestrus and estrus but not metestrus groups). Linear regression analysis of MPO versus Evans blue dye leak revealed a significant correlation between pulmonary neutrophil sequestration and lung leak (r = 0.9549; p < 0.0001).

CONCLUSION

Protection against T/HS-induced lung injury was greatest during the estrus and proestrus stages of the menstrual cycle and decreased with progression to diestrus. During the diestrus stage of the menstrual cycle when gonadal hormone levels are lowest, the rats are more sensitive to T/HS-induced lung injury, indicating that gonadal hormones modulate T/HS-induced lung injury.

Low doses of diagnostic energy X-rays protect against neoplastic transformation in vitro

PURPOSE

To investigate the effect of low doses of 60 kVp X-rays on in vitro transformation frequency.

MATERIALS AND METHODS

HeLa x skin fibroblast human hybrid cells were used to assay transformation from the non-tumorigenic to the tumorigenic phenotype. Subconfluent cultures of cells were exposed to a range of doses of 60 kVp X-rays and seeded for assay of transformation after 24 h post-irradiation holding. Experiments were repeated at least three times and the data pooled for analysis. Transformation frequencies were compared with those of sham-irradiated controls.

RESULTS

At doses < 1 cGy, the observed transformation frequencies were significantly less than those seen in unirradiated cells.

CONCLUSION

Low doses (< 1 cGy) of 60 kVp X-rays protect HeLa x skin fibroblast human hybrid cells against neoplastic transformation in vitro.

Glutamate-induced delta-catenin redistribution and dissociation from postsynaptic receptor complexes

Delta-catenin (or neural plakophilin-related arm-repeat protein/neurojungin) is primarily a brain specific member of the p120(ctn) subfamily of armadillo/beta-catenin proteins that play important roles in neuronal development. Our previous studies have shown that the ectopic expression of delta-catenin induces the formation of dendrite-like extensions and that the overexpression of delta-catenin promotes dendritic branching and increases spine density. Here we demonstrate that delta-catenin displays a dendritic distribution pattern in the adult mouse brain and is co-enriched with postsynaptic density-95 (PSD-95) in the detergent insoluble postsynaptic scaffolds. Delta-catenin forms stable complexes with excitatory neurotransmitter receptors including ionotropic N-methyl-D-aspartic acid receptor 2A (NR2A), metabotropic glutamate receptor 1alpha (mGluR1alpha), as well as PSD-95 in vivo. In cultured primary embryonic neurons, delta-catenin clusters co-distribute with filamentous actin and resist detergent extraction. In dissociated hippocampal neurons overexpressing delta-catenin, glutamate stimulation leads to a rapid redistribution of delta-catenin that can be attenuated by 6-cyano-7-nitroquinoxaline-2,3-dione and dizocilpine, selective inhibitors of ionotropic glutamate receptors. Upon glutamate receptor activation, delta-catenin becomes down-regulated and its association with NR2A and mGluR1alpha in cultured neurons is diminished. These findings support a possible functional connection between delta-catenin and the glutamatergic excitatory synaptic signaling pathway during neuronal development.

Claudin-8 interacts with multi-PDZ domain protein 1 (MUPP1) and reduces paracellular conductance in epithelial cells

The claudin family is a set of integral membrane proteins found at cell-cell interactions in tight junctions. To identify proteins that interact with claudin-8, we used the yeast two-hybrid system to search for binding partners. Using the C-terminal 37 amino acids of claudin-8 as bait, we screened a human kidney cDNA library and identified multi-PDZ domain protein 1 (MUPP1) as a claudin-8 binding protein. MUPP1 contains 13 PDZ domains and binds to claudin-8 though its PDZ9 domain. When MDCK cells were transfected with epitope-tagged claudin-8 or MUPP1, both molecules were concentrated at cell-cell junctions. The interaction of claudin-8 and MUPP1 in vivo was confirmed by co-immunolocalization and co-immunoprecipitation in MDCK cells. Expression of claudin-8-myc increased transepithelial electrical resistance (TER) and reduced paracellular flux using FITC-dextran as a tracer. Over-expression of FLAG-MUPP1 in MDCK cells also reduced the epithelial paracelhular conductance. Our results indicate that claudin-8 and MUPP1 interact in tight junctions of epithelial cells and are involved in the tight junction barrier function.

Status of trace elements in paddy soil and sediment in Taihu Lake region

Thirteen paddy soil profiles and river sediments which are sources of irrigation water were collected around the Taihu Lake, and the trace elements were estimated. The content of La and Ce in paddy soil and sediment were 39.3 and 68.6 mg/kg soil and 36.9 and 65.1 mg/kg soil, being within the range of background values. The values for Pb, Cu, Ni, Cr, Co, Mn, Zn, Se in paddy soil were 23.3, 27.8, 25.5, 63.5, 10.2, 386, 68.7 and 0.25 mg/kg soil respectively, all below the national permission level. There was a decline of Zn in paddy soil. Some of the river sediments were seriously polluted. The river in Yangjin site was most contaminated with 5.47 g Cu/kg and 7.4 g Zn/kg. The high concentration of Pb and Ni also was observed in this sediment. River in Weitang, Huashi, Xinzhuang and Meiyan were contaminated with Pb, Cu and Ni to some extent. Zn, Cu and Pb were the main pollutants in present experiment sites. The fast development of village/township industries have caused severe environmental pollution in the Taihu Lake region, especially irrigation river sediments. Se content in plant and seed was 0.04 and 0.03 mg/kg respectively, showed Se-deficiency in paddy soil in the Taihu Lake region.

Thymidine kinase of herpes simplex virus type 1 strain KOS lacks mutator activity

The effect of thymidine kinase (TK) encoded by herpes simplex virus type 1(HSV-1) strain KOS in DNA replication fidelity was examined by two different mutagenesis assays. Mutagenesis assay of the LacZ reporter gene present in recombinant tkLTRZ1, which contained the integrated LacZ gene in the tk locus, revealed a less than 0.05% mutation frequency of the LacZ gene regardless of whether the viruses were propagated in TK-expressing cells or control cells, conflicting an earlier report that a HSV-1 TK(+) strain replicated a 0.5% mutation frequency of the LacZ gene (R. B. Pyles and R. L. Thompson, 1994, J. Virol. 68, 4514-4524). Furthermore, TK-proficient and -deficient recombinant viruses replicated with similar mutation frequencies (0.027 and 0.026%, respectively) of the LacZ gene, which was integrated in the polymerase locus. Results of SupF mutagenesis assay demonstrated that neither the spectra of mutation nor the mutation frequencies of SupF gene, which was integrated in the tk locus of recombinant, were significantly different (P > 0.05) in progeny viruses grown in TK-expressing cells and control cells. Therefore, both LacZ and SupF mutagenesis assays demonstrated that TK of the HSV-1 strain KOS did not have detectable mutator activity.

[Study on regulators of the cell cycle in cutaneous squamous cell carcinoma]

In order to investigate the relationship between the regulators of cell cycle and cutaneous squamous cell carcinoma(SCC), we used an immunohistochemical staining technique to examine the expression of cyclin D1, p16 and Rb in the paraffin embedded skin cancer tissues of 30 patients with SCC. The positive percentage of cyclin D1, CDK4, p16 and Rb was 66.7%, 53.3%, 33.3%, and 36.7%, respectively. The overexpression of cyclin D1 and CDK4 could be observed frequently in low grade of differentiated cells, especially in marginal cells of the cancer nest. The results indicate that the aberrant expression of positive and negative regulators of the cell cycle may be involved in the carcinogenesis and evolution of SCC.

Green tea and its catechins inhibit breast cancer xenografts

Investigators have shown that green tea may decrease the risk of cancer. It is widely accepted that the main active component of green tea is epigallocatechin-3-gallate (EGCG). In this study, we examined the effect of green tea on breast cancer growth and endothelial cells in in vitro assays and in animal models. Furthermore, we compared the potency of the different catechin components of green tea extract (GTE), including EGCG. Our data showed that mixed GTE and its individual catechin components were effective in inhibiting breast cancer and endothelial cell proliferation. In mouse experiments, GTE suppressed xenograft size and decreased the tumor vessel density. Our results demonstrated the value of all catechins and argued for the use of a mixed GTE as a botanical dietary supplement, rather than purified EGCG, in future clinical trials.