Water and fat MR imaging with chemical shift selective 3D steady state methods

A new 3D acquisition regimen that enables the collection of conventional, water-suppressed, and fat-suppressed images with no increase in scan times compared with currently implemented 3D sequences is presented. The method is based on conventional 3D steady state with interleaved selective excitation of the fat resonance resulting in acquisition of a fat-based image during the TR period experienced by the water spins. This new sequence is relatively tolerant to susceptibility artifacts and results in excellent water-based images. Because the idea, which we propose, is independent of the type of steady-state imaging protocol utilized, it can be easily applied with regimens that are specifically tailored to enhance contrast.

Basic fibroblast growth factor stimulates proliferation and suppresses melanogenesis in cell cultures derived from early zebrafish embryos

We are attempting to develop methods for in vitro culture of zebrafish embryonal stem cells. Primary cultures were initiated from wild-type zebrafish early embryos in basal nutrient medium supplemented with insulin, selenite, leukemia inhibitory factor, trout serum, fetal bovine serum, and trout embryo extract. In this medium, melanocytes appeared on the second day of culture. Basic fibroblast growth factor (bFGF) was mitogenic when cells were plated at low densities. bFGF suppressed melanogenesis is a dose-dependent fashion, with maximal effect at 20 ng/mL. Cultures initiated and maintained with bFGF for 24 hours and then incubated without bFGF for as long as 8 days did not contain pigmented cells. Experiments in which bFGF was added or removed at various times after initiation of cultures indicated that maximum sensitivity to bFGF occurred during the first 12 hours of culture. When wild-type cells from cultures without bFGF were injected into albino blastula-stage embryos, melanocytes subsequently developed in host embryos: no melanocytes appeared when cells from cultures with bFGF were injected into albino hosts.

Analysis of metal-clad optical waveguide polarizers by the vector beam propagation method

The attenuation characteristics of a metal-clad planar optical waveguide polarizer are computed by a modified finite-difference beam propagation method, taking into consideration the complex refractive indices of the metals used and the vector characteristics of the guided mode. Numerical results for practical optical waveguide refractive-index profiles such as the step and Gaussian distributions are presented. The method should find applications in the design of metal-clad optical waveguide polarizers and other lossy waveguide devices with arbitrary refractive-index profiles and can be easily expanded to three-dimensional cases.

Study of the irreversible adsorption of proteins on polybutadiene-coated zirconia

The cause of irreversible adsorption of proteins on polybutadiene-coated zirconia is investigated by comparing the chromatographic properties of polybutadiene-coated zirconia with that of other reversed-phase packing materials such as bonded phase silica, polybutadiene-coated alumina and polybutadiene-coated silica. We find that the polybutadiene-coated zirconia has a micropore size distribution similar to that of the polybutadiene-coated alumina, from which some proteins can be eluted. Thus, the irreversible adsorption of proteins on polybutadiene-coated zirconia is not caused by entrapment of proteins in the micropores of the packing. The high hydrophobicity of the polybutadiene coating and the strong Lewis acid sites on the zirconia surface cause strong interactions between proteins and the stationary phase, the combination of which lead to irreversible adsorption of proteins on polybutadiene-coated zirconia.

Toxic heavy metals and other trace elements in foodstuffs from 12 different countries. An IAEA coordinated research program

A research program related to the assessment of toxic heavy metals and essential trace elements in foodstuffs has been carried out in 12 countries under the auspices of the IAEA. The main purpose of this program was to obtain data on the elemental concentrations of potentially toxic elements in foodstuffs in various countries, and to compare them with the maximum permissible levels specified in national legislation and international guidelines. High-priority elements for this study were As, Cd, Cr, Pb, Hg, and Se. Also of interest, but of lower priority, were Sb, Cu, and Zn. Emphasis was placed on the use of nuclear and nuclear-related analytical techniques, complemented by conventional methods, and on quality assurance.

Vasoactive intestinal peptide inhibits interleukin (IL)-2 and IL-4 production through different molecular mechanisms in T cells activated via the T cell receptor/CD3 complex

The neuropeptide vasoactive intestinal peptide (VIP) has been reported previously to inhibit cell proliferation and interleukin (IL)-2 production in mitogen-stimulated T lymphocytes. In physiological conditions, T lymphocytes are specifically activated by antigen-binding through the T cell receptor (TCR). Here we report on the effect of VIP and related peptides on IL-2 and IL-4 production of murine T lymphocytes stimulated through the TCR. VIP inhibited IL-2 and IL-4 production (both at the level of protein concentration and biological activity) by unfractionated spleen cells or purified CD4+ T cells stimulated with either anti-CD3 monoclonal antibodies (mAbs) or with anti-CD3 mAbs plus phorbol esters. The inhibition was dose-dependent, and specific, since structurally related peptides such as secretin and glucagon had little or no inhibitory activity. VIP inhibited IL-2 and IL-4 production through different molecular mechanisms. IL-2 production was regulated at a transcriptional level through the downregulation of IL-2 mRNA, whereas the production of IL-4 was modulated at a posttranscriptional level.

A prospective, randomized, blinded, and placebo-controlled trial of intraoperative intra-arterial urokinase infusion during lower extremity revascularization. Regional and systemic effects

OBJECTIVE

This study was designed to evaluate the safety and regional and systemic effects of three doses of urokinase (UK) infused into the distal arterial circulation during routine operative lower extremity revascularization.

METHODS

One hundred thirty-four patients were prospectively randomized to receive one of three bolus doses of UK (125,000, 250,000, or 500,000 U) or placebo (saline) infused into the distal circulation before lower extremity bypass for chronic limb ischemia. Regional (femoral vein) and systemic (arm) blood was sampled before drug infusion, prereperfusion, and postreperfusion, and systemic blood samples were obtained 2 hours postreperfusion. Assays evaluated plasma levels of fibrinogen, fibrin(ogen) degradation products (FDP), fibrin breakdown products (D-dimer and fragment B-beta 15-42), and plasminogen. Patients were monitored for clinically evident bleeding complications. The Wilcoxon rank-sum test was used to compare different drug doses with the placebo.

RESULTS

Intraoperative bolus UK infusions produced no significant fibrinogen breakdown compared with placebo. There was a dose-related decline in plasminogen levels, which became significant at a dose of 500,000 U of UK (p < 0.001). There were dose-related increases in plasma FDP, which became significant at dose of 250,000 and 500,000 U (p < or = 0.005), and in plasma D-dimer, which were significant at all UK doses (p < 0.001). The changes in plasma fibrinogen and markers of fibrin breakdown were similar in the regional and systemic circulations. There was no increase in operative blood loss, blood replaced, or wound hematoma formation. There was an unexplained increased mortality in the placebo group (21.1% vs. 2.0%, p = 0.033).

CONCLUSIONS

Intraoperative bolus UK infusion is safe, with no significant fibrinogen depletion or increased operative blood loss or wound hematoma formation. Dose-related plasminogen activation resulted in significant breakdown in cross-linked fibrin in the distal circulation. Intraoperative bolus UK infusion may be valuable as an adjunct in patients with chronic occlusive disease who are undergoing revascularization. Detailed randomized studies are indicated to establish clinical efficacy.

The role of growth regulatory aberrations in progression of human colon carcinoma

Colon carcinoma is a multistage disease. Most malignancies arise from pre-existing benign tumors. Multiple chromosomal defects affecting oncogene and tumor suppressor gene function are associated with disease progression. These aberrations result in an imbalance between the normal positive and negative growth effectors, which contribute further to disease progression. We have studied how changes in the expression of TGF alpha and TGF beta affect colon carcinoma cell behavior. Overexpression of the stimulatory factor TGF alpha in a relatively benign cell line with weak TGF alpha autocrine activity converted the cell type to an aggressive, progressed phenotype in vivo and in vitro. In contrast, disruption of TGF alpha expression by constitutive expression of TGF alpha antisense RNA in a progressed cell line with a strong, internalized autocrine loop resulted in the development of clones with decreased tumorigenicity in vitro and in vivo. Suppression of the inhibitory effects of TGF beta by constitutive expression of TGF beta antisense RNA increased the tumorigenicity of the cell lines in vitro and in vivo. None of these alterations in TGF alpha or TGF beta expression affected the doubling time of the cells. The changes in tumorigenicity were due to effects on the lag phase of growth. We conclude that TGF beta functions to maintain the cells in a quiescent state while TGF alpha drives reentry into the cell cycle. We have identified a unique cis-element that mediates TGF alpha autoregulation. The transcription factor binding this element is also involved in the cell-cycle regulation of TGF alpha expression. We hypothesize that this factor may be a convergent point TGF alpha and TGF beta interact in controlling movement into and out of quiescence.

Synthesis and biological evaluation of tetrademethyl isocolchicine derivatives as inhibitors of DNA topoisomerase action in vitro

Four tetrademethyl isocolchicine analogs were prepared and evaluated as inhibitors of mammalian DNA topoisomerase in vitro. All compounds inhibited topoisomerase II-dependent DNA unknotting by a mechanism which did not involve "cleavable-complex" formation. N-Deacetylation as well as N-substitution with the (3',4',5'-trihydroxybenzoyl)-group afforded compounds which were less selective, based on their added ability to inhibit topoisomerase I-mediated DNA relaxation.

Cosegregation of the renin gene with an increase in mean arterial blood pressure in the F2 rats of SHR-WKY cross

Using the restriction endonuclease, Bgl I, Samani et al. found a restriction fragment length polymorphism (RFLP) for the renin gene in spontaneously hypertensive rats (SHR) and its normotensive control Wistar-Kyoto (WKY) rats (1). This RFLP was confirmed in our laboratory in SHR and WKY rats using a rat renin cDNA probe. The correlation of blood pressure and the renin RFLP was examined in 106 F2 rats produced from F1 rats, the offspring of a cross between SHR males and WKY females. Systolic blood pressure was measured by the tail cuff method at 12 weeks of age. Mean arterial blood pressure of anesthetized rats was measured by cannulation of the femoral artery prior to sacrifice. The frequency of renin genotype showed a typical 1:2:1 Mendelian ratio in F2 rats of SHR and WKY cross. The mean arterial blood pressure of F2 rats homozygous with the SHR allele was significantly higher than F2 rats that were heterozygous or homozygous for the WKY allele. No significant difference in systolic blood pressure was observed in F2 rats with different genotypes. Thus, the renin gene RFLP cosegregates with an increase in mean arterial blood pressure in the F2 rats of SHR and WKY cross.

Effect of acupuncture and point-injection treatment on immunologic function in rheumatoid arthritis

The results of treatment of 54 cases of rheumatoid arthritis (RA) by warm needling (WN) and point-injection (PI) with Zhuifengsu are reported. Good clinical results were observed with an effective rate of 100%. At the same time, changes in cellular and humoral immunity and other parameters in peripheral blood were noted before and after treatment. The NK activity and IL-2 value in RA patients were found to be lower than those of normal individuals; both increased after treatment (P < 0.01). This suggests that the WN and PI with Zhuifengsu exert a regulatory effect on the cellular immunological function.

Vasoactive intestinal peptide downregulates the expression of IL-2 but not of IFN gamma from stimulated murine T lymphocytes

The neuropeptide vasoactive intestinal peptide (VIP) has been previously reported to inhibit T cell proliferation. Here we report on the effect of VIP on IL-2 and on IFN gamma production by murine T lymphocytes stimulated with mitogens (ConA), or activated through the antigen-specific T cell receptor. VIP inhibited IL-2 production by either unfractionated spleen cells, or by purified CD4+ T cells in a dose-dependent manner. The effect was specific, since structurally related peptides such as secretin and glucagon had little or no inhibitory effect. VIP induced a rapid increase in intracellular cAMP in CD4+ T cells, suggesting that the inhibitory effect of VIP could be mediated through the induction of cAMP. Northern blots showed that VIP downregulated IL-2 mRNA, indicating the occurrence of a transcriptional regulatory event. In contrast with its effect on IL-2, VIP did not affect IFN gamma production by either mitogen-stimulated normal T lymphocytes, or by the L12R4 murine T cell line which produces IFN gamma in response to PMA stimulation.

Modified finite-difference beam-propagation method based on the Douglas scheme

A modified finite-difference beam-propagation method (FD-BPM) based on the Douglas scheme is presented. The truncation error in the modified FD-BPM is reduced to o(Deltax)(4) in the transverse direction, whereas the error in the conventional FD-BPM is typically o(Deltax)(2). With trivial programming changes, the accuracy can be improved without the introduction of additional computation time. Numerical results obtained for a slab optical waveguide and a directional coupler illustrate the advantage of this method.

Anti-AIDS agents, 9. Suberosol, a new C31 lanostane-type triterpene and anti-HIV principle from Polyalthia suberosa

A new C31 lanostane-type triterpene, assigned the trivial name suberosol [1], has been isolated from Polyalthia suberosa as an anti-HIV principle. The structure has been characterized as 24-methylenelanost-7,9(11)-diene-3 beta, 15 alpha-diol (suberosol) [1], based on spectroscopic evidence. Compound 1 was found to show anti-HIV replication activity in H9 lymphocyte cells with an EC50 of 3 micrograms/ml.

Activation of phospholipase A2 and stimulation of prostaglandin E2 production by transforming growth factor-alpha in rat thymic epithelial cells requires influx of calcium

The stimulation of both phospholipase A2 (PLA2) enzymic activity and the production of prostaglandin E2 (PGE2) by transforming growth factor-alpha (TGF-alpha) and Ca2+ ionophore A23187 in TEA3A1 rat thymic epithelial cells were studied. TGF-alpha by itself at various concentrations (5-200 ng/ml) had no effect on the stimulation of PGE2 production. A23187 (1 microgram/ml) by itself stimulated PGE2 production on average by 18-fold over the control. When TGF-alpha (50 ng/ml) was added to the cells in the presence of A23187, a synergistic stimulation (on average 45-fold) of PGE2 production was observed. Synergistic stimulation was also observed at the level of arachidonic acid released from phospholipid pools, suggesting the activation of PLA2 enzymic activity. We have found that this synergistic activation of PLA2 enzymic activity and subsequent stimulation of PGE2 production required the activation of epidermal growth factor (EGF) receptor tyrosine kinase and Ca2+ influx. This was shown by the fact that genistein, an inhibitor of tyrosine kinase, blocks the synergistic stimulation by TGF-alpha and A23187 and by the fact that the stimulation of PGE2 production by TGF-alpha and A23187 is dependent on the culture-medium Ca2+ concentrations. The requirement for Ca2+ influx instead of intracellular mobilization of Ca2+ was shown by the fact that PGE2 production was not stimulated when cells were treated with TGF-alpha and thapsigargin. Moreover, the synergistic stimulation of PGE2 production by TGF-alpha and A23187 was not affected in protein kinase C down-modulated cells. In addition, the synergistic stimulation was not observed in cells treated with either phorbol 12-myristate 13-acetate (PMA) and TGF-alpha or PMA and A23187, and in cells treated with TGF-alpha and thapsigargin. The requirement for the activation of receptor tyrosine kinase seems to be specific to the EGF receptor, since a synergistic stimulation of PGE2 production was not observed when cells are treated with either insulin-like growth factor-I or fibroblast growth factor-I in the presence of A23187.

C3 synthesis by A549 alveolar epithelial cells is increased by interferon-gamma and dexamethasone

The third component of complement, C3, is produced in the lung by several cell types including alveolar epithelial cells. Since interferon-gamma (IFN-gamma) and dexamethasone regulate C3 gene expression in non-pulmonary cells, and because IFN-gamma and dexamethasone interact to regulate the functional activity of alveolar epithelial cells, we investigated the effects of IFN-gamma and dexamethasone on C3 production by A549 human alveolar epithelial cells. Treatment of A549 cells with IFN-gamma alone increased C3 production in a time-and dose-dependent manner. Maximal increase in C3 production occurred after stimulation of A549 cells with 500 IU/ml IFN-gamma for 3 days and was 3.4-fold greater than control. Dexamethasone (0.1 microM) stimulation of A549 cells increased C3 production 6.7-fold over controls on day 3. Treatment of A549 cells with IFN-gamma plus dexamethasone resulted in an 11-to 13-fold increase in C3 synthesis. C3 mRNA levels were increased in A549 cells treated with IFN-gamma and dexamethasone individually and in combination suggesting that IFN-gamma and dexamethasone increase C3 synthesis by a pre-translational mechanism. IFN-gamma and dexamethasone did not alter the two-chain structure of the C3 molecule produced by A549 cells, as assessed by Western blotting. We speculate that IFN-gamma and glucocorticoids may be important in the local regulation of C3 synthesis in the lung.

Antitumor agents. 141. Synthesis and biological evaluation of novel thiocolchicine analogs: N-acyl-, N-aroyl-, and N-(substituted benzyl)deacetylthiocolchicines as potent cytotoxic and antimitotic compounds

Three series of novel thiocolchicine analogs, N-acyl-, N-aroyl-, and N-(substituted benzyl)-deacetylthiocolchicinoids, have been synthesized and evaluated for their cytotoxicity against various tumor cell lines, especially solid tumor cell lines, and for their inhibitory effects on tubulin polymerization in vitro. Most of these compounds showed strong inhibitory effects on tubulin polymerization comparable to that obtained with thiocolchicine and greater than that obtained with colchicine. Only compounds with a long side chain at the C(7) position, such as 22-24, did not inhibit tubulin polymerization. Several of the active N-aroyldeacetylthiocolchicine analogs had positive optical rotations, in contrast to the negative optical rotation observed with most colchicinoids. This property might be attributed to a reversal of biaryl configuration from the normal aS to aR. Therefore, the N-aroyl analogs were further evaluated by circular dichroism, which readily distinguishes between the aS and aR biaryl configurations. This latter technique demonstrated that the active N-aroyl analogs do have an aS configuration despite their positive optical rotations. However, comparison of 1H NMR and UV spectral data of N-(substituted benzyl)-deacetylthiocolchicines with those of corresponding N-aroyldeacetylthiocolchicines suggested a different biaryl dihedral angle [even though these compounds have the same aS biaryl configuration]. The similar tubulin binding properties of these compounds suggest that a biaryl dihedral angle of 53 degrees is not essential for colchicinoid-tubulin interaction. The increased cytotoxicity of N-(substituted benzyl)deacetylthiocolchicines compared to the N-aroyldeacetylthiocolchicines may be attributed to different lipophilicity, drug uptake, or drug metabolism in the tumor cells. The side chain at the C(7) position affects inhibition of tubulin polymerization and the cytotoxic activity of colchicinoids as a function of its size and its contribution to lipophilicity.

Analysis of respiratory syncytial virus genetic variability with amplified cDNAs

Antigenic and genetic heterogeneities exist within the two major antigenic groups of respiratory syncytial (RS) virus. We developed a polymerase chain reaction (PCR)-based assay that not only differentiates the two RS virus groups but allows distinctions within groups on the basis of changes in the nucleotide sequences, as revealed by restriction fragment analysis. In this assay, viral RNA served as a template for cDNA synthesis with extension from a synthetic oligonucleotide primer complementary to bases 164 to 186 in the F protein mRNA. For PCR amplification, two group-specific 5' primers were added. The two primers corresponded to the G protein mRNA sequence of group B (bases 10 to 30) or group A (bases 247 to 267) RS virus. Agarose gel electrophoresis readily discriminated the 1.1-kb group B and the 0.9-kb group A virus amplification products. All 47 viruses tested were assigned to the same group by both PCR and monoclonal antibody reaction pattern analysis. Restriction fragment analysis of the amplified DNAs revealed 12 restriction patterns for group A viruses and 7 restriction patterns for group B viruses, while the monoclonal antibody reaction patterns revealed seven patterns for group A viruses and 3 patterns for group B viruses. Most viruses with the same monoclonal antibody reaction patterns had different restriction patterns, and some viruses with the same restriction patterns had different monoclonal antibody reaction patterns. Thus, the results of the PCR assay concurred with the monoclonal antibody reaction pattern analysis for group classification of RS viruses, while the restriction fragment analysis identified greater diversity within groups than was seen with the monoclonal antibody analysis.

Development and longevity of Nosopsyllus laeviceps kuzenkovi (Siphonaptera) from Inner Mongolia under laboratory conditions

The development and longevity of Nosopsyllus laeviceps kuzenkovi (Yagubyants), a major plague vector among sylvan and campestral rodents in Inner Mongolia, China, was studied under controlled laboratory conditions of 11, 14, 17, 20, 23, 26, 29, and 35 C at 76% relative humidity (R.H.), and 32, 53, 76, 87, and 100% at 23 C. Development from egg to adult was shortest (21-23 days) under favorable conditions of 26 C at 76% R.H., but maximum survival to adulthood (84%) occurred at 23 C. Average longevity was 13.25 days (13.70 in females and 12.80 in males) at 17 C and 76% R.H.; it was longer at cooler and shorter at warmer temperatures. Findings provided experimental data that helped clarify seasonal fluctuations, summer mortality, generation cycles, and survival of compared flea species from Russia, Azerbaidzhan, and China.

Antitumor agents. 139. Synthesis and biological evaluation of thiocolchicine analogs 5,6-dihydro-6(S)-(acyloxy)- and 5,6-dihydro-6(S)-[(aroyloxy)methyl]-1,2,3-trimethoxy-9-(methylthio)-8H- cyclohepta[a]naphthalen-8-ones as novel cytotoxic and antimitotic agents

A series of novel thiocolchicine analogs, 5,6-dihydro-6(S)-(acyloxy)-and 5,6-dihydro-6(S)-[(aroyloxy)-methyl]-1,2,3-trimethoxy-9-(methylthi o)-8H- cyclohepta[a]naphthalen-8-ones, possessing a six-membered ring B, have been synthesized and evaluated for their cytotoxicity against various tumor cell lines, including solid tumor cell lines, and for their interaction with tubulin. The configuration of the parent alcohol (compound 5) was established unequivocally as (aR,6S) by X-ray crystallographic analysis. The side chain at the C(6) position is in a pseudoaxial orientation. The optical properties and 1H NMR data indicated that these compounds have the same conformations in solution as in the solid state. Biological results showed that compounds (5, 6, 14, 15, 17, and 18) bearing a small side chain at C(6) demonstrate high potency in inhibiting tubulin polymerization and binding of radiolabeled colchicine to tubulin. The most cytotoxic compounds were 14, 15, 17, and 18, with good activity against several solid tumor cell lines. To explain the strong antitubulin activity of compound 5 (with an aR configured biaryl system in contrast to the aS configuration previously described for colchicinoids, allocolchicinoids, and steganacin) we speculate that a rapid atropisomerism equilibrium must exist for 5 and its active derivatives. This equilibrium would yield adequate amounts of aS-configured conformers that interact, strongly with tubulin. Since the optically inactive 18 is also a potent inhibitor of tubulin, the configuration of the side chain of these six-membered ring B analogs cannot be essential for their binding to tubulin. Instead we propose that the size of ring B and of its side chain play important roles in tubulin binding activity by affecting the rotation of the rings A and C along their linking C-C bond axis.

The distorted alpha 2-adrenoceptor genotype distribution in F2 populations of Dahl salt sensitive and resistant rats cross

To examine the role of the alpha 2-adrenoceptor gene in the development of genetic hypertensive rats, we tested Dahl salt sensitive (S) and resistant rats (R) for the presence of a restriction fragment length polymorphism (RFLP) in that gene. An RFLP was found between the S and R rats with a human kidney cDNA alpha 2-adrenoceptor probe (alpha 2-C4) and Msp I restriction endonuclease. The alpha 2-C4 probe detected two alleles, S and R, of 3.0 and 2.8 kb in size. The two strains of rats were each homozygous for their corresponding allele. The inheritance of the alleles was investigated by crossbreeding S and R rats and subsequent brother/sister mating of F1 rats. Two hundred and fifteen F2 rats were produced by breeding 14 pairs of F1 rats. An atypical distribution of alpha 2-adrenoceptor genotypes was observed. We found a reduced number of the SS genotype in both males and females of the F2 generation. To investigate the mechanism of this distorted alpha 2-adrenoceptor genotype distribution in the F2 rats of S and R cross, we backcrossed the F1 rats to their S and R parents. The litter size and gender distribution were counted for each breeding colony. Analysis by chi-square test showed that there was no sex difference among the backcrosses. Also, there was no significant decrease in litter size. This excludes the possibilities of fetal demise of S homozygotes and intrauterine selection. Therefore the deficiency of SS genotype may be due to gene recombination or may not be due to the alpha 2-adrenoceptor gene itself, but to the effect of other genes closely linked to the alpha 2-adrenoceptor.