The nanostructure and hydrogenation reaction of Mg50Co50 BCC alloy prepared by ball-milling

Mg50Co50 alloy before and after hydrogenation was investigated by means of transmission electron microscopy (TEM). Mg50Co50 alloy before hydrogenation was found to contain crystals not larger than 5 nm in size. Selected-area electron diffraction patterns (SAEDPs) revealed that these nanocrystals have a body-centered cubic (BCC) structure with a lattice parameter of about 0.3 nm. Distribution of Mg and Co elements in the Mg50Co50 alloy was uniform, indicated by energy dispersive x-ray spectroscopy (EDS) analysis. Crystallization and decomposition occurred in the Mg50Co50 alloy during hydrogenation. A large number of crystals larger than 10 nm were observed in the hydrogenated sample. The SAEDPs showed polycrystalline rings corresponding to the BCC phase and the Co metal phase. The existence of Mg-rich Mg-Co crystals and Co particles was also confirmed by TEM-EDS analysis.

Advanced Glycation End-products Enhance Calcification in Vascular Smooth Muscle Cells

Advanced glycation end-products (AGEs), senescent macroprotein derivatives formed at an accelerated rate in diabetes, are closely associated with vascular calcification in humans. In this study, the hypothesis that AGEs enhance calcification in cultured vascular smooth muscle cells (VSMCs) was tested. Using real-time polymerase chain reaction (PCR) and specific protein assays, it was demonstrated that rat aortic VSMCs incubated with AGEs exhibited an increased expression of the AGE receptor (RAGE) and typical bone proteins, such as osteopontin and alkaline phosphatase. Incubation with AGEs also enhanced calcium accumulation in VSMCs in time-and dose-dependent manners. These AGEs-mediated changes in VSMCs were partially attenuated by a neutralizing antibody to RAGE. The results suggest that AGEs that accumulate in diabetes could elicit the osteoblastic differentiation of VSMCs, thereby contributing to vascular calcification via the RAGE pathway. Interruption of the AGE-RAGE interaction might be a promising target for therapeutic intervention to prevent diabetic vascular calcification.

Calcium taste preferences: genetic analysis and genome screen of C57BL/6J x PWK/PhJ hybrid mice

To characterize the genetic basis of voluntary calcium consumption, we tested C57BL/6J mice (B6; with low avidity for calcium), PWK/PhJ mice (PWK; with high avidity for calcium) and their F(1) and F(2) hybrids. All mice received a series of 96-h two-bottle preference tests with a choice between water and the following: 50 mm CaCl(2), 50 mm calcium lactate, 50 mm MgCl(2), 100 mm KCl, 100 mm NH(4)Cl, 100 mm NaCl, 5 mm citric acid, 30 microm quinine hydrochloride and 2 mm saccharin. Most frequency distributions of the parental and F(1) but not F(2) groups were normally distributed, and there were few sex differences. Reciprocal cross analysis showed that B6 x PWK F(1) mice had a non-specific elevation of fluid intake relative to PWK x B6 F(1) mice. In the F(2) mice, trait correlations were clustered among the divalent salts and the monovalent chlorides. A genome screen involving 116 markers showed 30 quantitative trait loci (QTLs), of which six involved consumption of calcium chloride or lactate. The results show pleiotropic controls of calcium and magnesium consumption that are distinct from those controlling consumption of monovalent chlorides or exemplars of the primary taste qualities.

Dose-dependent protective effect of propofol against mitochondrial dysfunction in ischaemic/reperfused rat heart: role of cardiolipin

BACKGROUND AND PURPOSE

Ischaemia damages to the cardiac mitochondria by increasing generation of reactive oxygen species (ROS) and peroxidation of cardiolipin. The inhibited mitochondrial function leads to the cardiac injury during reperfusion. Propofol (2, 6-diisopropylphenol), an intravenous anaesthetic, has been shown to decrease cardiac ischaemia and reperfusion injury. In the present study, we propose that propofol protects mitochondrial function and decreases cardiac injury by prevention of cardiolipin peroxidation during ischaemia and reperfusion.

EXPERIMENTAL APPROACH

After isolation of mitochondria from isolated rat heart perfused on a Langendorff model, various mitochondrial bioenergetic parameters were evaluated such as rates of mitochondrial oxygen consumption, H(2)O(2) production, complex I and III activity as well as the degree of lipid peroxidation and cardiolipin content. The action of propofol was also explored in isolated mitochondria. And the effect of cardiolipin was evaluated by fusing cardiolipin liposome with mitochondria.

KEY RESULTS

Propofol treatment had strong dose-dependent protection attenuating these parameters alterations in reperfused rat heart and isolated mitochondria. Additionally, cardiolipin treatment had the same protective effect, compared with propofol treatment at high concentration.

CONCLUSIONS AND IMPLICATIONS

The protective effect of propofol appears to be due, at least in part, as a chemical uncoupler, to the interruption of the vicious circle of ROS-cardiolipin-complexes of the respiratory chain-ROS through preserving the content and integrity of cardiolipin molecules by ROS attack. These findings may provide an explanation for some of the factors responsible for cardioprotection and one approach exploring an available antioxidant.

Allelic distribution of HLA class I genes in the Tibetan ethnic population of China

Tibetans live in Qinghai-Tibet Plateau rising about 4000 m a.s.l. in south-west China. Archaeological evidences suggested that there have been humans living in Tibet at least 5000 years ago. However, Tibetan earlier history remains elusive. In the present study, allelic distribution of human leucocyte antigen (HLA)-A, -B and -Cw in 158 unrelated Tibetan Chinese was investigated using sequencing-based typing methods, and a total of 25 HLA-A, 45 HLA-B and 20 HLA-Cw alleles were identified. A*24G1 (27.2%), B*51G1 (16.8%), Cw*04G1 (13.3%) and Cw*070201G1 (13.3%) are the most common HLA-A, -B and -Cw alleles. The most frequently detected haplotypes were A*24G1-B*51G1-Cw*140201 (3.6%), A*24G1-B*51G1 (6.8%), A*02G1-Cw*070201G1 (6.5%) and B*51G1-Cw*140201 (5.0%). Chi-squared test suggested that all three loci fitted the Hardy-Weinberg expectations. No evidence for a departure from selective neutrality at the HLA-A and -B loci was observed. However, significant departure of the observed homozygosity from the expected values was found for HLA-Cw. Though the contemporary Tibetans inhabit the south-west China, Nei's genetic distance measure based on frequencies of HLA-A, -B and -Cw indicated that Tibetans were closer to northern Han Chinese, Mongolian Chinese, Koreans and Japanese rather than to southern Han Chinese. The corresponding dendrogram constructed according to the neighbour-joining method supported that Tibetans separated from southern Han and located in North-East Asian cluster which included northern Han Chinese and Mongolian Chinese. These data were in good agreement with language classification and with a recent hypothesis that Tibetan might originate from northern China along Yellow river.

Transformation of carbon tetrachloride by bisulfide treated goethite, hematite, magnetite, and kaolinite

This study investigated the transformation of carbon tetrachloride (CT) by goethite, hematite, magnetite, and kaolinite treated with bisulfide to form coatings of iron monosulfide (FeS) and other Fe(II) species. These coatings contribute to abiotic natural attenuation in anaerobic environments. Batch kinetic experiments were performed under anoxic conditions at pH 8.0. Surface-area-normalized pseudo-first-order rate constants for CT transformation did not differ significantly for the three HS- treated iron oxides, but the rate of CT transformation by bisulfide-treated kaolinite was significantly lower, most likely due to kaolinite's lower iron content. The yield of chloroform (CF) from CT transformation was typically approximately 1%. There was negligible or only slight adsorption of several natural organic matter (NOM) model compounds to the surface of HS- treated goethite, and these compounds had no influence on CT transformation rate constants or CF yields. Juglone, on the other hand, adsorbed to a greater extent, and also significantly influenced the CF yield, increasing it by a factor of approximately 20 for HS- treated hematite. We speculate that juglone or its HS- addition product adsorbed to the mineral surface and acted as a hydrogen atom donor that reacted with the trichloromethyl radical intermediate, increasing the CF yield.

The feasibility study of using non-woven MBR for reduction of hydrolysed biosolids

In this study, non-woven MBR was used to treat hydrolysed biosolids wasted from a biological treatment plant. The concentration of SS of hydrolysed biosolids in influent was 10,000 mg/L and the concentration of SS in effluent was less than 200 mg/L with/without discharging wasted sludge depending on different HRTs, i.e. 20, 15 and 10 d. The results indicated that the percentage of biosolids reduction in terms of SS removal efficiency in non-woven MBR was around 65, 60 and 35%, respectively, depending on different HRTs. Meanwhile, the ratio of VSS/SS was decreased from 0.78 to 0.50 and the number of smaller inorganic particle sizes increased due to extended SRT. The initial flux in the non-woven MBR was set at 0.02, 0.04 and 0.06 m3/m2/day and trans-membrane pressure (TMP) was less than 10 kPa. The permeate flux could be maintained quite stably due to lower TMP. The proposed non-woven MBR could be used to achieve the reduction of biosolids in the wastewater treatment plant.

The accuracy of dynamic wedge dose computation in the ADAC Pinnacle RTP system

The nonphysical wedge is a modality that uses computer‐controlled jaw motion to generate wedge‐shaped dose distributions. There are Varian enhanced dynamic wedges (EDWs) and Siemens virtual wedges (VWs). We recently commissioned dynamic wedges on both Varian and Siemens LINACs. The beam data, acquired with a Wellhöfer chamber array and a Sun Nuclear profiler, are used for modeling in the ADAC Pinnacle system. As recommended by ADAC, only a limited number of beam data is measured and used for beam modeling. Therefore, the dose distributions of dynamic wedges generated by Pinnacle must be examined. Following the commissioning of the dynamic wedges, we used Pinnacle to generate a number of dose distributions with different energies, wedge angles, field sizes, and depths. The computed data from Pinnacle are then compared with the measured data.

The deviations of the output factor in all square and rectangular fields are mostly within 2.0% for both EDW and VW. For asymmetric fields, the deviations are within 3%. However, exceptions of differences more than 3% have been found in a larger field and large wedge combinations. The precision of the beam profiles generated by Pinnacle is also evaluated. As a result of this investigation, we present a scope of quality assurance tests that are necessary to ensure acceptable consistency between the delivered dose and the associated treatment plan when dynamic wedges are applied.

PACS numbers: 8753 Dq, 87.53.Xd

A novel applicator for low-dose-rate brachytherapy of gynecological cancers

The standard low-dose-rate (LDR) delivery system utilized in the definitive management of patients with cervical carcinoma involves an intrauterine tandem and a pair of vaginal colpostats (ovoids). This well-known application system may deliver inadequate dosage if the tumor extends to the lower vaginal mucosa. During the gauze packing of the ovoids, either operator error or narrowing of the vaginal apex can result in mal-alignment of the colpostats and subsequent inadequate dosing to the ecto-cervix. A novel vaginal cylinder has been designed to address these concerns. Beginning January 1, 2001, patients with cancer of the cervix, endometrium, or vagina requiring LDR brachytherapy have been enrolled into an institutionally sanctioned clinical trial. As of May 31, 2001, a total of 11 patients have been entered but only 10 were successfully implanted with the test device. Patient follow-up has ranged from 0.81 years to 1.2 years (median: 0.96 years). Using our study applicator, all patients received within 10% of the preimplant prescribed dose to tumor. Also, no one had cumulative dosage that exceeded 10% of the maximum allowed dose to the critical normal tissues. Thus far, all study patients have had no clinical evidence of persistence/recurrence of disease or complications from treatment. The preliminary results presented herein clearly demonstrate the feasibility of this novel LDR vaginal cylinder in the treatment of a variety of clinical situations involving gynecological cancers. Our institutional trial is continuing.

A novel applicator for low-dose-rate brachytherapy of gynecological cancers

The standard low-dose-rate (LDR) delivery system utilized in the definitive management of patients with cervical carcinoma involves an intrauterine tandem and a pair of vaginal colpostats (ovoids). This well-known application system may deliver inadequate dosage if the tumor extends to the lower vaginal mucosa. During the gauze packing of the ovoids, either operator error or narrowing of the vaginal apex can result in mal-alignment of the colpostats and subsequent inadequate dosing to the ecto-cervix. A novel vaginal cylinder has been designed to address these concerns. Beginning January 1, 2001, patients with cancer of the cervix, endometrium, or vagina requiring LDR brachytherapy have been enrolled into an institutionally sanctioned clinical trial. As of May 31, 2001, a total of 11 patients have been entered but only 10 were successfully implanted with the test device. Patient follow-up has ranged from 0.81 years to 1.2 years (median: 0.96 years). Using our study applicator, all patients received within 10% of the preimplant prescribed dose to tumor. Also, no one had cumulative dosage that exceeded 10% of the maximum allowed dose to the critical normal tissues. Thus far, all study patients have had no clinical evidence of persistence/recurrence of disease or complications from treatment. The preliminary results presented herein clearly demonstrate the feasibility of this novel LDR vaginal cylinder in the treatment of a variety of clinical situations involving gynecological cancers. Our institutional trial is continuing.

Induction of neurite extension and survival in pheochromocytoma cells by the Rit GTPase

The Rit, Rin, and Ric proteins comprise a distinct and evolutionarily conserved subfamily of the Ras-like small G-proteins. Although these proteins share the majority of core effector domain residues with Ras, recent studies suggest that Rit uses novel effector pathways to regulate NIH3T3 cell proliferation and transformation, while the functions of Rin and Ric remain largely unknown. Since we demonstrate that Rit is expressed in neurons, we investigated the role of Rit signaling in promoting the differentiation and survival of pheochromocytoma cells. In this study, we show that expression of constitutively active Rit (RitL79) in PC6 cells results in neuronal differentiation, characterized by the elaboration of an extensive network of neurite-like processes that are morphologically distinct from those mediated by the expression of oncogenic Ras. Although activated Rit fails to stimulate mitogen-activated protein kinase/extracellular-signal-regulated kinase (MAPK/ERK) signaling pathways in COS cells, RitL79 induced the phosphorylation of ERK1/2 in PC6 cells. We also find that Rit-mediated effects on neurite outgrowth can be blocked by co-expression of dominant-negative mutants of C-Raf1 or mitogen-activated protein kinase kinase 1 (MEK1). Moreover, expression of dominant-negative Rit is sufficient to inhibit NGF-induced neurite outgrowth. Expression of active Rit inhibits growth factor-withdrawal mediated apoptosis of PC6 cells, but does not induce phosphorylation of Akt/protein kinase B, suggesting that survival does not utilize the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Instead, pharmacological inhibitors of MEK block Rit-stimulated cell survival. Taken together, these studies suggest that Rit represents a distinct regulatory protein, capable of mediating differentiation and cell survival in PC6 cells using a MEK-dependent signaling pathway to achieve its effects.

Nerve growth factor-dependent activation of the small GTPase Rin

The Rit and Rin proteins comprise a distinct and evolutionarily conserved subfamily of Ras-related small GTPases. Although we have defined a role for Rit-mediated signal transduction in the regulation of cell proliferation and transformation, the function of Rin remains largely unknown. Because we demonstrate that Rin is developmentally regulated and expressed in adult neurons, we examined its role in neuronal signaling. In this study, we show that stimulation of PC6 cells with either epidermal growth factor or nerve growth factor (NGF) results in rapid activation of Rin. This activation correlates with the onset of Ras activation, and dominant-negative Ras completely inhibits Rin activation induced by NGF. Further examination of Ras-mediated Rin activation suggests that this process is dependent upon neuronally expressed regulatory factors. Expression of mutationally activated H-Ras fails to activate Rin in non-neuronal cells, but results in potent stimulation of Rin-GTP levels in a variety of neuronal cell lines. Furthermore, although constitutively activated Rin does not induce neurite outgrowth on its own, both NGF-induced and oncogenic Ras-induced neurite outgrowth were inhibited by the expression of dominant-negative Rin. Together, these studies indicate that Rin activation is a direct downstream effect of growth factor-dependent signaling in neuronal cells and suggest that Rin may function to transduce signals within the mature nervous system.

Identification and characterization of cis elements in the STAT3 gene regulating STAT3 alpha and STAT3 beta messenger RNA splicing

Signal transducer and activator of transcription 3 (STAT3) is an oncogene and a critical regulator of multiple cell-fate decisions, including myeloid cell differentiation. Two isoforms of STAT3 have been identified: alpha (p92) and beta (p83). These differ structurally in their C-terminal transactivation domains, resulting in distinct functional activities. The cis genetic elements that regulate the ratio of alpha to beta messenger RNA (mRNA) are unknown. In this study, cloning, sequencing, and splicing analysis of the human and murine STAT3 genes revealed a highly conserved 5' donor site for generation of both alpha and beta mRNA and distinct branch-point sequences, polypyrimidine tracts, and 3' acceptor sites (ASs) for each. The beta 3' AS was found to be located 50 nucleotides downstream of the alpha 3' AS in exon 23. Two additional cryptic 3' ASs (delta and epsilon) were also identified. Thus, we identified for the first time the cis regulatory sequences responsible for generation of STAT3 alpha and STAT3 beta mRNA.

Melatonin reverses the profibrillogenic activity of apolipoprotein E4 on the Alzheimer amyloid Abeta peptide

Inheritance of apoE4 is a strong risk factor for the development of late-onset sporadic Alzheimer's disease (AD). Several lines of evidence suggest that apoE4 binds to the Alzheimer Abeta protein and, under certain experimental conditions, promotes formation of beta-sheet structures and amyloid fibrils. Deposition of amyloid fibrils is a critical step in the development of AD. We report here that addition of melatonin to Abeta in the presence of apoE resulted in a potent isoform-specific inhibition of fibril formation, the extent of which was far greater than that of the inhibition produced by melatonin alone. This effect was structure-dependent and unrelated to the antioxidant properties of melatonin, since it could be reproduced neither with the structurally related indole N-acetyl-5-hydroxytryptamine nor with the antioxidants ascorbate, alpha-tocophenol, and PBN. The enhanced inhibitory effects of melatonin and apoE were lost when bovine serum albumin was substituted for apoE. In addition, Abeta in combination with apoE was highly neurotoxic (apoE4 > apoE3) to neuronal cells in culture, and this activity was also prevented by melatonin. These findings suggest that reductions in brain melatonin, which occur during aging, may contribute to a proamyloidogenic microenvironment in the aging brain.

RERG is a novel ras-related, estrogen-regulated and growth-inhibitory gene in breast cancer

Using microarray analysis, we identified a unique ras superfamily gene, termed RERG (ras-related and estrogen-regulated growth inhibitor), whose expression was decreased or lost in a significant percentage of primary human breast tumors that show a poor clinical prognosis. Importantly, high RERG expression correlated with expression of a set of genes that define a breast tumor subtype that is estrogen receptor-positive and associated with a slow rate of tumor cell proliferation and a favorable prognosis for these cancer patients. RERG mRNA expression was induced rapidly in MCF-7 cells stimulated by beta-estradiol and repressed by tamoxifen treatment. Like Ras, RERG protein exhibited intrinsic GDP/GTP binding and GTP hydrolysis activity. Unlike Ras proteins, RERG lacks a known recognition signal for COOH-terminal prenylation and was localized primarily in the cytoplasm. Expression of RERG protein in MCF-7 breast carcinoma cells resulted in a significant inhibition of both anchorage-dependent and anchorage-independent growth in vitro and inhibited tumor formation in nude mice. These features of RERG are strikingly different from most Ras superfamily GTP-binding pro-teins and suggest that the loss of RERG expression may contribute to breast tumorigenesis.

Expanding the diversity of the IS630-Tc1-mariner superfamily: discovery of a unique DD37E transposon and reclassification of the DD37D and DD39D transposons

A novel transposon named ITmD37E was discovered in a wide range of mosquito species. Sequence analysis of multiple copies in three Aedes species showed similar terminal inverted repeats and common putative TA target site duplications. The ITmD37E transposases contain a conserved DD37E catalytic motif, which is unique among reported transposons of the IS630-Tc1-mariner superfamily. Sequence comparisons and phylogenetic analyses suggest that ITmD37E forms a novel family distinct from the widely distributed Tc1 (DD34E), mariner (DD34D), and pogo (DDxD) families in the IS630-Tc1-mariner superfamily. The inclusion in the phylogenetic analysis of recently reported transposons and transposons uncovered in our database survey provided revisions to previous classifications and identified two additional families, ITmD37D and ITmD39D, which contain DD37D and DD39D motifs, respectively. The above expansion and reorganization may open the doors to the discovery of related transposons in a broad range of organisms and help illustrate the evolution and structure-function relationships among these distinct transposases in the IS630-Tc1-mariner superfamily. The presence of intact open reading frames and highly similar copies in some of the newly characterized transposons suggests recent transposition. Studies of these novel families may add to the limited repertoire of transgenesis and mutagenesis tools for a wide range of organisms, including the medically important mosquitoes.

MsqTc3, a Tc3-like transposon in the yellow fever mosquito Aedes aegypti

A novel transposon, MsqTc3-Aa, has been discovered in the yellow fever mosquito, Aedes aegypti. Evidence of its past mobility is presented. There are approximately 100 copies of MsqTc3-Aa in A. aegypti, eight of which have been isolated and sequenced. All sequenced copies are more than 99% identical to their consensus, indicating recent mobilization. The MsqTc3-Aa consensus contains imperfect terminal inverted repeats (TIRs) and an open reading frame (ORF) interrupted by an intron. Sequence, structural and phylogenetic analysis showed that MsqTc3-Aa is a distant relative of Tc3, an active transposon in Caenorhabditis elegans. These results may provide useful information for the current effort to control mosquito-borne diseases using genetic approaches.

Requirement of B7-mediated costimulation in the induction of experimental autoimmune anterior uveitis

PURPOSE

To study the role of costimulatory signaling through the CD28-B7 interaction in experimental autoimmune anterior uveitis (EAAU).

METHODS

Naive Lewis rats were immunized with insoluble melanin-associated antigen (MAA) derived from bovine iris and ciliary body. CTLA4-Fc, a recombinant protein comprised of the extracellular domain of human CTLA4 bound to mouse IgG2a Fc, was used to block the CD28-B7 interaction. A mutant version (CTLA4-Fc-mutant) was used as a control. The effect of CTLA4-Fc on the in vivo induction of disease with MAA was studied. Subsequently, the mechanism by which CTLA4-Fc blocked the interaction of CD28 and B7 was investigated in vivo, using the adoptive transfer of T cells derived from CTLA4-Fc-treated rats, and in vitro, using the proliferative response and cytokine production of MAA-T cells in the presence of CTLA4-Fc.

RESULTS

CTLA4-Fc markedly reduced the incidence and severity of EAAU in Lewis rats after sensitization with MAA. The adoptive transfer of sensitized T cells from CTLA4-Fc-treated donors did not induce EAAU in naive recipients. CTLA4-Fc inhibited the expansion of antigen-specific MAA-T cells and the production of TNF-alpha.

CONCLUSIONS

The costimulatory signal delivered through CD28-B7 is required for the induction and pathogenesis of EAAU. In the absence of this signal, antigen-specific expansion of MAA reactive T cells as well as production of TNF-alpha is inhibited. Abrogation of this costimulatory signal may be an important therapeutic option for EAAU.

Molten-globule structure and membrane binding of the N-terminal protease-resistant domain (63-193) of the steroidogenic acute regulatory protein (StAR)

The first step in steroidogenesis is the movement of cholesterol from the outer to inner mitochondrial membrane; this movement is facilitated by the steroidogenic acute regulatory protein (StAR). StAR has molten-globule properties at low pH and a protease-resistant N-terminal domain at pH 4 and pH 8 comprising residues 63-193. To explore the mechanism of action of StAR we investigated the structural properties of the bacterially expressed N-terminal domain (63-193 StAR) using CD, limited proteolysis and NMR. Far- and near-UV CD showed that the amount of secondary structure was greater at acidic than at neutral pH, but there was little tertiary structure at any pH. Unlike 63-193 StAR liberated from N-62 StAR by proteolysis, biosynthetic 63-193 StAR was no longer resistant to trypsin or proteinase K at pH 7, or to pepsin at pH 4. Addition of trifluoroethanol and SDS increased secondary structure at pH 7, and dodecylphosphocholine and CHAPS increased secondary structure at pH 2, pH 4 and pH 7. However, none of these conditions induced tertiary structure, as monitored by near-UV CD or NMR. Liposomes of phosphatidylcholine, phosphatidylserine and their mixture increased secondary structure of 63-193 StAR at pH 7, as monitored by far-UV CD, and stable protein-liposome complexes were identified by gel-permeation chromatography. These results provide further evidence that the N-terminal domain of StAR is a molten globule, and provide evidence that this conformation facilitates the interaction of the N-terminal domain of StAR with membranes. We suggest that this interaction is the key to understanding the mechanism of StAR's action.

[Study of chemical constituents of essential oil from flowers of Mikania micrantha H.B.K]

The essential oil from flowers of Mikania micrantha H.B.K were extracted and its chemical constituents were analyzed by GC/MS. Forty-two compounds were identified and the main compounds with high contents were beta-cubebene (12.95%), allo-aromadendrene (11.67%), beta-caryophyllene (9.17%), 1H-inden-1-one, 5-(1, 1-dimethylethyl)-2, 3-(6.23%), beta-himaohalene (4.56%), trans-alpha-bergamotene (4.09%), limonene (3.68%), beta-ocimene (2.53%).

Nicotine and amyloid formation

The major protein constituents of amyloid deposits in Alzheimer's disease (AD) are the 40-residue beta-amyloid (Abeta) (1-40) peptide and the 42-residue Abeta(1-42) peptide. The Abeta(1-42) is more pathogenic and produced in greater quantities in familial forms of AD. A major goal of research is to uncover a suitable inhibitor that either slows down or inhibits Abeta formation (beta-amyloidosis). During beta-amyloidosis, structural changes associated with the conversion of monomeric Abeta peptide building blocks into the aggregated fibrillar beta-sheet structures occur (alpha-helix-->beta-sheet or random, extended chain-->beta-sheet). In previous work, we and others established that nicotine, a major component of cigarette smoke, inhibits beta-amyloidosis of the Abeta(1-42), which may result from nicotine binding to the alpha-helical structure. These conclusions were based on solution nuclear magnetic resonance (NMR) spectroscopic studies with the nonnative 28-residue Abeta(1-28). This information suggests that, when administered therapeutically to AD patients, nicotine may not only affect cholinergic activation, but could also conceivably alter amyloid deposition. In this report, NMR studies were augmented with the naturally occurring Abeta(1-42), under conditions where the peptide folds into a predominantly alpha-helical or random, extended chain structure. The major result is that nicotine shows only modest binding to these conformations, indicating that the nicotine inhibition to beta-amyloidosis probably results from binding to a small, soluble beta-sheet aggregate that is NMR invisible.

[Sequencing of inhA in drug-resistant Mycobacterium tuberculosis isolates]

OBJECTIVE

To determine and characterize inhA mutations of drug-resistant isolates of Mycobacterium tuberculosis.

METHODS

PCR products of inhA of drug-resistant and susceptible isolates and H(37)R(v) were purified, cloned and analyzed by ABI 377 auto-DNA sequencing system.

RESULTS

11 out of 17 drug-resistant M. Tuberculosis isolates were detected having inhA variations. 10 out of the 11 strains with variations had at least one missense mutation. The variations consisted of point mutation (transition, transversion and deletion). Molecular mechanisms were different from strain to strain. 8 of 13 (62%) strains had both katG and inhA mutations. 18 variation positions and mechanisms different from previous report have been described.

CONCLUSION

These results suggested that binding sites decrease caused by inhA point mutations be associated with M. tuberculosis' resistance to INH and EMB.

Rit, a non-lipid-modified Ras-related protein, transforms NIH3T3 cells without activating the ERK, JNK, p38 MAPK or PI3K/Akt pathways

The biological functions of Rit (Ras-like protein in tissues) and Rin (Ras-like protein in neurons), members of a novel branch of Ras-related GTP-binding proteins that are approximately 50% identical to Ras, have not been characterized. Therefore, we assessed their activity in growth control, transformation and signaling. NIH cells stably expressing a constitutively activated mutant of Rit [Rit(79L)] (analogous to the oncogenic mutant H-Ras(61L)) demonstrated strong growth transformation, proliferating rapidly in low serum and forming colonies in soft agar and tumors in nude mice. Although Rit(79L) alone did not promote morphologically transformed foci, it cooperated with both Raf and Rho A to form Rac/Rho-like foci. Rin [Rin(78L)] cooperated only with Raf. Rit(79L) but not Rin(78L) stimulated transcription from luciferase reporter constructs regulated by SRF, NF-kappaB, Elk-1 and Jun. However, neither activated ERK, JNK or p38, or PI3-K/Akt kinases in immune complex kinase assays. Interestingly, although Rit lacks any known recognition signal for C-terminal lipidation, Rit-transformed cell growth and survival in low serum is dependent on a farnesylated protein, as treatment with farnesyltransferase inhibitors caused apoptosis. Rin cooperated with Raf in focus assays but did not otherwise function in these assays, perhaps due to a lack of appropriate effector pathways in NIH3T3 fibroblasts for this neural-specific Ras family member. In summary, although Rit shares most core effector domain residues with Ras, our results suggest that Rit uses novel effector pathways to regulate proliferation and transformation.

A novel RalGEF-like protein, RGL3, as a candidate effector for rit and Ras

The small GTPase Rit is a close relative of Ras, and constitutively active Rit can induce oncogenic transformation. Although the effector loops of Rit and Ras are highly related, Rit fails to interact with the majority of the known Ras candidate effector proteins, suggesting that novel cellular targets may be responsible for Rit transforming activity. To gain insight into the cellular function of Rit, we searched for Rit-binding proteins by yeast two-hybrid screening. We identified the C-terminal Rit/Ras interaction domain of a protein we have designated RGL3 (Ral GEF-like 3) that shares 35% sequence identity with the known Ral guanine nucleotide exchange factors (RalGEFs). RGL3, through a C-terminal 99-amino acid domain, interacted in a GTP- and effector loop-dependent manner with Rit and Ras. Importantly, RGL3 exhibited guanine nucleotide exchange activity toward the small GTPase Ral that was stimulated in vivo by the expression of either activated Rit or Ras. These data suggest that RGL3 functions as an exchange factor for Ral and may serve as a downstream effector for both Rit and Ras.

[A comparison between latanoprost and timolol in treatment of patients with primary open-angle glaucoma and ocular hypertension]

OBJECTIVE

To evaluate the therapeutic value of latanoprost on glaucoma.

METHODS

In an open-label fashion, multicenter, randomized control clinical trial, the efficacy and adverse drug reactions of topical application of 0.005% latanoprost once daily were compared with that of 0.5% timolol twice daily for 12 weeks in patients with open-angle glaucoma or ocular hypertension.

RESULTS

The study included 128 patients (63 patients in latanoprost group and 65 patients in timolol group) and 117 patients remained at the end of the study (60 cases in latanoprost group and 57 cases in timolol group). Comparing 12 weeks with baseline diurnal intraocular pressure (IOP), the IOP reduction (mean +/- standard deviation) in latanoprost group was (7.5 +/- 0.3) mm Hg (1 mm Hg = 0.133 kPa) (32%, t = 22.73, P < 0.0001) greater than the reduction in timolol group (6.1 +/- 0.3) mm Hg (26%, t = 17.94, P < 0.0001), the difference between the two groups being significant (F = 9.54, P = 0.0026). Two patients treated with timolol and none treated with latanoprost were withdrawn from the study because of inadequate IOP control; 3 patients with latanoprost had foreign body sensation. In latanoprost group, there was one patient whose eyelashes became darker and longer at the last visit (the 12th week). No ocular and systemic adverse events related to the two drugs were found.

CONCLUSION

It is demonstrated that 0.005% latanoprost topically applied once daily is well tolerated and more effective in reducing IOP than 0.5% timolol topically applied twice daily. Thus, latanoprost has the potential to be a new first-line antiglaucoma drug.

Nicotine dependence and its familial aggregation in Chinese

BACKGROUND

Nicotine dependence is a significant public health problem. This study attempted to characterize the prevalence and familial aggregation of nicotine dependence in China.

METHODS

In 1998, we initiated a community-based cross-sectional study among residents of the Yuexi County in Anqing, China. A total of 991 current smokers from 488 randomly selected nuclear families were recruited and surveyed by use of the standardized Fagerstrom Test of Nicotine Dependence (FTND) questionnaire and the Revised Tolerance Questionnaire (RTQ). All study subjects were offspring in their respective nuclear families, and 478 male-male pairs (aged 41.7 +/- 12.1 years) were finally used for data analyses, because the number of female current smokers (n = 5) was too small.

RESULTS

The correlation coefficient of the FTND and the RTQ scores was as high as 0.84 (P < 0.0001). Nicotine dependence, defined as an FTND score > or =8 or an RTQ score > or =28, had a prevalence of 12.7% and 11.1%, respectively. The respective sibling recurrent risk was 1.7 and 2.4, according to the FTND or the RTQ criteria. The adjusted odds ratios and 95% CI of nicotine dependence of second siblings in families in which the first sibling was nicotine dependent were 2.13 (95% CI: 1.02-4.43) and 3.50 (95% CI: 1.65-7.36) respectively, according to the FTND and RTQ criteria.

CONCLUSIONS

The prevalence of nicotine dependence in male current smokers in China was comparable to that reported in previous US and European studies. Our findings suggest that genetic influences may play an important role in vulnerability to nicotine addiction.

Rem2, a new member of the Rem/Rad/Gem/Kir family of Ras-related GTPases

Here we report the molecular cloning and biochemical characterization of Rem2 (for Rem, Rad and Gem-related 2), a novel GTP-binding protein identified on the basis of its homology with the Rem, Rad, Gem and Kir (RGK) family of Ras-related small GTP-binding proteins. Rem2 mRNA was detected in rat brain and kidney, making it the first member of the RGK family to be expressed at relatively high levels in neuronal tissues. Recombinant Rem2 binds GTP saturably and exhibits a low intrinsic rate of GTP hydrolysis. Surprisingly, the guanine nucleotide dissociation constants for both Rem2 and Rem are significantly different than the majority of the Ras-related GTPases, displaying higher dissociation rates for GTP than GDP. Localization studies with green fluorescent protein (GFP)-tagged recombinant protein fusions indicate that Rem2 has a punctate, plasma membrane localization. Deletion of the C-terminal seven amino acid residues that are conserved in all RGK family members did not affect the cellular distribution of the GFP fusion protein, whereas a larger deletion, including much of the polybasic region of the Rem2 C-terminus, resulted in its redistribution to the cytosol. Thus Rem2 is a GTPase of the RGK family with distinctive biochemical properties and possessing a novel cellular localization signal, consistent with its having a unique role in cell physiology.

[Clinical observation of palitaxel in the treatment of gynecologic malignant tumors]

OBJECTIVE

To observe the therapeutic effect of palitaxel.

METHODS

Of 37 cases, 33 were treated when tumor recurrence occurred after surgery or chemotherapy. There were 27 cases with ovarian cancer, 6 with fallopian tube cancer. 3 with cervix cancer, and 1 with endometrium cancer. In all cases, diagnosis was confirmed by histopathology. Palitaxel (135-150 mg/m2) was administered i.v. or i.p. once every three werks in combination with cisplatin (PDD) 60 mg/m2 and cyclophosphamide (CTX) 60 mg/d. Antihistaminics and antiemetic were given prior to palitaxel. The results of treatment were compared with those in 37 cases treated in the some time period with PAC or VBP regimen.

RESULTS

The overall median survival time of the control group was 4 months, and 8.5 months in the palitaxel treated group (P < 0.001). The response rate was 18.9% and 48.6% respectively (P < 0.005). The major toxic effects was myelosuppression and alopecia.

CONCLUSION

Palitaxel is effective in the treatment of advanced gynecological tumors.

Biochemical characterization of the Ras-related GTPases Rit and Rin

We report the biochemical characterization of Rit and Rin, two members of the Ras superfamily identified by expression cloning. Recombinant Rit and Rin bind GTP and exhibit intrinsic GTPase activity. Conversion of Gln to Leu at position 79 (for Rit) or 78 (for Rin) (equivalent to position 61 in Ras) resulted in a complete loss of GTPase activity. Surprisingly, significant differences were found when the guanine nucleotide dissociation constants of Rit and Rin were compared with the majority of Ras-related GTPases. Both proteins display higher k(off) values for GTP than GDP in the presence of 10 mM Mg(2+). These GTP dissociation rates are 5- to 10-fold faster than most Ras-like GTPases. Despite these unique biochemical properties, our data support the notion that both Rit and Rin function as nucleotide-dependent molecular switches. To begin to address whether these proteins act as regulators of distinct signaling pathways, we examined their interaction with a series of known Ras-binding proteins by yeast two-hybrid analysis. Although Rit, Rin, and Ras have highly related effector domain sequences, Rit and Rin were found to interact with the known Ras binding proteins RalGDS, Rlf, and AF-6/Canoe but not with the Raf kinases, RIN1, or the p110 subunit of phosphatidylinositol 3-kinase. These interactions were GTP and effector domain dependent and suggest that RalGDS, Rlf, and AF-6 are Rit and Rin effectors. Their biochemical properties and interaction with a subset of known Ras effector proteins suggest that Rit and Rin may play important roles in the regulation of signaling pathways and cellular processes distinct from those controlled by Ras.

Slow accumulation of active mitogen-activated protein kinase during thymocyte differentiation regulates the temporal pattern of transcription factor gene expression

Thymocyte-positive selection is believed to result from low affinity/avidity interactions of TCR and MHC proteins, but how these weak interactions translate into downstream biochemical signals and how such signals modulate gene expression is unknown. Using a culture system where isolated immature thymocytes can be induced to differentiate along the CD4 lineage pathway, we show that sustained low level mitogen-activated protein/extracellular regulated kinase activity is required for cell differentiation and survival. Furthermore, induction of mitogen-activated protein/extracellular regulated kinase activity is surprisingly slow under conditions that induce differentiation. This pattern of kinase activity not only selects which genes are expressed but also regulates the temporal pattern of expression of transcription factor genes that are induced during double-positive thymocyte differentiation.

Martin-Gruber communicating branch: anatomical and histological study

We dissected 72 upper limbs of fresh cadavers and found 17 cases with a Martin-Gruber communicating branch (23.6%). These were classified into 4 types: type I (n = 5, 29.4%): communicating branch between the anterior interosseous and ulnar nn, type II (n = 3, 17.6%): Communicating branch between the median and ulnar nn., type III (n = 3, 17.6%): Communicating branch between the muscular branches to the flexor digitorum profundus m., type IV (n = 6, 35.3%): combination of type I or II and type III. At histologic examination the number and size of the nerve bundles each communicating branch contained proved to be very different. In one case of type II only a single nerve bundle was found. We suggest that the different numbers of nerve bundles innervate different amounts of the intrinsic hand musculature. The communicating branch with a single nerve bundle probably innervated only the first dorsal interosseous muscle.

Grafting of genetically modified human fetal fibroblasts to produce human butyrylcholinesterase in mice

Human diploid fibroblast cultures were established from fetal skin tissue. Enzymic dissociation yielded cultures of higher growth capacity of fibroblasts than those prepared by mechanical dissociation followed by spontaneous outgrowth of cells. Transfer of recombinant human butyrylcholinesterase (BChE, EC 3.1.1.8) gene into primary human fibroblasts was achieved successfully using lipofection and retrovirus-mediated transfection. The analysis of drug-resistant colonies suggested the presence of the transcripted BChE mRNA in the cytoplasm of transfected cells. The secreted BChE protein in culture medium was assayed for enzyme activity using butyrylthiocholine as substrate. The genetically modified fibroblasts were mixed with rat tail collagen and transplanted subcutaneously and intraperitoneally to mice. Immunoreactive human BChE appeared in the plasma from the transplanted mice. reaching the top level at day 13. It was not present any longer in most of the mice 20 days later.

Long terminal repeat sequences of equine infectious anaemia virus are a major determinant of cell tropism

The Wyoming strain of equine infectious anaemia virus (EIAV) is a highly virulent field strain that replicates to high titre in vitro only in primary equine monocyte-derived macrophages. In contrast, Wyoming-derived fibroblast-adapted EIAV strains (Malmquist virus) replicate in primary foetal equine kidney and equine dermis cells as well as in the cell lines FEA and Cf2Th. Wyoming and Malmquist viruses differ extensively both in long terminal repeat (LTR) and envelope region sequences. We have compared the promoter activities of the Wyoming LTR with those of LTRs derived from fibroblast-adapted viruses by examining their abilities to drive a luciferase reporter gene as well as by construction of infectious molecular clones differing only in LTR sequence. Our results indicate that LTR sequences are a major restriction for growth of the Wyoming strain of EIAV in fibroblasts.

[Anatomic study and review of the literature on the Martin Gruber anastomosis]

We dissected 72 upper limbs of fresh cadavers and found 17 cases of the Martin-Gruber anastomosis. The incidence was 23.6%. They can be classified into 5 types. Type I (n = 5, 29.4%): Communication between the anterior interosseous and the ulnar nerves. Type II (n = 3, 17.6%): Communication between the median and the ulnar nerves. Type III (n = 3, 17.6%): Communication between the muscular branches of the flexor digitorum profundus muscle (FDP). Type IV (n = 3, 17.6%): Communication between the anterior interosseous and the ulnar nerves, the muscular branches of the flexor digitorum profundus muscle (FDP) originated from the connection. Type V (n = 3, 17.6%): The anastomotic branch originated from the median nerve and joined the ulnar at two different points as well as connecting with the ulnar branch of the FDP. Through histologic examination, we found the number and size of nerve fascicles which every connection contained to be very different. In one case of type II only one single nerve fascicle was found. We propose the hypothesis that the different amounts of nerve fascicles innervate different amounts of intrinsic hand musculature. The communication which contained one single nerve fascicle only innervate the first dorsal interosseous muscle (FDI).

Solution structures of micelle-bound amyloid beta-(1-40) and beta-(1-42) peptides of Alzheimer's disease

The amyloid beta-peptide is the major protein constituent of neuritic plaques in Alzheimer's disease. The beta-peptide varies slightly in length and exists in two predominant forms: (1) the shorter, 40 residue beta-(1-40), found mainly in cerebrovascular amyloid; and (2) the longer, 42 residue beta-(1-42), which is the major component in amyloid plaque core deposits. We report here that the sodium dodecyl sulphate (SDS) micelle, a membrane-mimicking system for biophysical studies, prevents aggregation of the beta-(1-40) and the beta-(1-42) into the neurotoxic amyloid-like, beta-pleated sheet structure, and instead encourages folding into predominantly alpha-helical structures at pH 7.2. Analysis of the nuclear Overhauser enhancement (NOE) and the alphaH NMR chemical shift data revealed no significant structural differences between the beta-(1-40) and the beta-(1-42). The NMR-derived, three-dimensional structure of the beta-(1-42) consists of an extended chain (Asp1-Gly9), two alpha-helices (Tyr10-Val24 and Lys28-Ala42), and a looped region (Gly25-Ser26-Asn27). The most stable alpha-helical regions reside at Gln15-Val24 and Lys28-Val36. The majority of the amide (NH) temperature coefficients were less than 5, indicative of predominately strong NH backbone bonding. The lack of a persistent region with consistently low NH coefficients, together with the rapid NH exchange rates in deuterated water and spin-labeled studies, suggests that the beta-peptide is located at the lipid-water interface of the micelle and does not become inbedded within the hydrophobic interior. This result has implications for the circulation of membrane-bound beta-peptide in biological fluids, and may also facilitate the design of amyloid inhibitors to prevent an alpha-helix-->beta-sheet conversion in Alzheimer's disease.

Perioperative cimetidine application modulates natural killer cells in patients with colorectal cancer: a randomized clinical study

Thirty-eight colorectal cancer patients were randomly assigned to treatment group, which took cimetidine in the perioperative period, and control group to which no drug was given. Twenty healthy volunteers served as normal controls. NK cells were measured by immunocytochemical technique. The results showed that NK percentages before treatment in both groups of patients were significantly lower than those in normal controls (P < 0.05). NK cell percentages at admission, before operation, on the 2nd and the 10th postoperative days were 14.84 +/- 4.41, 15.74 +/- 3.75, 17.21 +/- 3.69, 21.05 +/- 4.54, respectively, for the treatment group, and 15.00 +/- 2.77, 13.05 +/- 2.46, 14.21 +/- 2.19, 15.58 +/- 1.68, respectively, for control group. The difference was statistically significant (P < 0.01), suggesting that the perioperative administration of cimetidine could help restore NK cells in colorectal cancer patients.

A role for p21ras/MAP kinase in TCR-mediated activation of LFA-1

LFA-1 is a beta2 integrin that plays well-characterized roles in adhesion of T lymphocytes to APC, T cell-mediated cytolysis, and leukocyte-endothelial cell interactions. Although it is clear that LFA-1 must undergo affinity or avidity changes to bind its cellular ligand ICAM-1, the intracellular signaling pathways involved are not well characterized. Here, we show that the Ras-mitogen-activated protein kinase (MAPK) signaling pathway is also involved in TCR-activated LFA-1 adhesion. Expression of a dominant negative form of p21ras in a thymocyte cell line inhibits, while constitutively active p21ras both enhances and sustains, subsequent TCR-triggered adhesion to isolated ICAM-1. However, the Ras/MAPK pathway alone is not sufficient for activating T cell LFA-1, as inhibition of both downstream MAPK/extracellular regulated kinase kinase (MEK) activity and phosphatidylinositol 3-kinase activity is required for complete inhibition of adhesion.

[Regulating function of enzymization and deenzymization of the lactate dehydrogenase isozymes in the mouse tissues during hypoxia]

OBJECTIVE

Study the characteristics of changes of LDH enzyme map of mouse under slight hypoxia.

METHODS

Treated mouse with artificial hypoxia, various tissue biopsies were made for the test of LDH enzymatic activity by specific staining technical LDH(1-5)relative percent enzymatic activity were measured with CS-910 dual-wavelength thin-layer chromatography scanner.

RESULTS

The relative percent enzymatic activity of LDH isozymes of various tissues after slight hypoxia shift to the isozymes LDH1 and LDH2, whose principal subunits are H subunits, and the relative percent enzymatic activity of LDH1 (H4), LDH2-(H3M) increased (the relative percent enzymatic activity of LDH2 increased markedly, P < 0.05), while LDH (M4) in various tissues decreased prominently except the cardiac muscle, and that of LDH4 (HM3) decreased as well. After the PAGE of the hypoxia treated cardiac muscle specimen was made, activity subbands originated regularly in the isozyme pattern of LDH, with the regularity of LDH1 (0 subband), LDH2 (0-1 subbands), LDH3 (0-2 subbands), LDH4 (1-3 subbands), LDH5 (2-4 subbands). After adding appropriate amount of NAD+ to mouse cardiac muscle specimen with hypoxia, PAGE showed the numbers of subbands of four kinds of isozymes (LDH2-LDH5) decreased even totally disappeared in the isozyme pattern.

CONCLUSIONS

The negative feedback regulation of enzymization and deenzymization of LDH isozymes is one of mouse stress responses to slight hypoxia.