Poly(A) site choice during mRNA 3'-end formation in the Schizosaccharomyces pombe wos2 gene

In the fission yeast Schizosaccharomyces pombe, the wos2 gene encodes p23, a highly conserved protein which functions as a co-chaperone for the heat shock protein Hsp90. This p23 protein binds to Hsp90, but its activities and regulatory mechanisms are still unclear. Northern analysis has shown that the wos2 gene produces three transcripts of about 1.1, 0.9 and 0.8 kb, which are expressed differentially depending on the growth temperature. The largest and the smallest transcripts were most abundant at 25 degrees C, whereas the 0.9-kb transcript predominated at 37 degrees C. A time-course analysis indicated that this 0.9-kb species rapidly increased in abundance after a shift from 25 degrees C to 37 degrees C, reaching a maximum after 15 min. A shift back to 25 degrees C resulted in a decline in the amount of this transcript, albeit at a slower rate. Expression analysis of wos2:ura4 and nmt1:wos2 constructs showed that the 3' untranslated region of wos2 alone directs the formation of these multiple, discrete wos2 mRNAs. Sequence analysis of cDNAs derived from these mRNAs showed that the use of different polyadenylation sites results in the production of the three differently sized wos2 transcripts. In the case of the 0.9- and 0.8-kb mRNA species, these sites lie in a predicted hairpin loop in the mRNA, suggesting that polyadenylation signals in wos2 transcripts may be mediated by RNA secondary structure. The possibility that differential thermal stability of these hairpin structures could influence polyadenylation site choice during formation of the 3'-ends of the mRNAs is discussed.

Macrophage inducible nitric oxide synthase gene expression is blocked by a benzothiophene derivative with anti-HIV properties

Nitric oxide (NO) has been shown to mediate multiple physiological and toxicological functions. The inducible nitric oxide synthase (iNOS) is responsible for the high output generation of NO by macrophages following their stimulation by cytokines or bacterial antigens. The inhibition of TNF alpha-stimulated HIV expression and the anti-inflammatory property of PD144795, a new benzothiophene derivative, have been recently described. We have now analyzed whether some of these properties could be mediated by an effect of PD144795 on NO-dependent inflammatory events. We show that PD144795 suppresses the lipopolysaccharide-elicited production of nitrite (NO(-)(2)) by primary peritoneal mouse macrophages and by a macrophage-derived cell line, RAW 264.7. This effect was dependent on the dose and timing of addition of PD144795 to the cells. Suppression of NO(-)(2) production was associated with a decrease in the amount of iNOS protein, iNOS enzyme activity and mRNA expression. The effect of PD144795 was partially abolished by coincubation of the cells with LPS and IFN gamma. However, the inhibitory effect of PD144795 was not abrogated by the simultaneous addition of LPS and TNF alpha, which indirectly suggests that the effect of PD144795 was not due to the inhibition of TNF alpha synthesis. Additionally, PD144795 did not block NF-kappa B nuclear translocation induced by LPS. Inhibition of iNOS gene expression represents a novel mechanism of PD144795 action that underlines the anti-inflammatory effects of this immunosuppressive drug.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Cellular rejection and rate of progression of transplant vasculopathy: a 3-year serial intravascular ultrasound study

Intravascular ultrasound (IVUS) is established as the optimal method for early detection of transplant vasculopathy. The association between cellular rejection and development of transplant vasculopathy remains controversial. This study attempts to determine the rate of progression of transplant vasculopathy lesions and its relationship with cellular rejection in a long-term (> 1 year) IVUS serial follow-up.A study cohort of 47 patients undergoing heart transplantation from 1993 to 1995 was evaluated. Intravascular ultrasound was performed at baseline (within 8 weeks) and annually for a period of 3 years to determine maximum intimal thickness and maximum plaque area in each coronary segment. Significant allograft vasculopathy was defined as a site with intimal thickness > 0.5 mm not present at baseline. Biopsy results were scored by assigning a numerical weight to each ISHLT grade during the first year. Donor lesions ranged from 0.86 to 1.1 mm, showing no evidence of progression at serial follow-up. De novo lesions were identified in 30 patients. These lesions appeared yearly but progressed slowly. The average biopsy score in the entire cohort was 1.1 +/- 0.8. Average biopsy score was > 1.0 in 35 patients with significant linear correlation between the rate of intimal progression and biopsy score (r = 0.42, p = 0.01). Multivariate analysis demonstrated that only the biopsy score correlated with the rate of progression. Lesions of donor atherosclerosis do not change significantly after transplantation. However, de novo lesions continue to develop every year. In patients with evidence of rejection, the rate of progression of transplant vasculopathy correlates with the severity of rejection.

Vaccines--a wonderful tool for equity in health

Equity is a word representing one of the most important concerns for planners, politicians and the academia. It comes as an answer to the permanent rediscovery of inequity in the benefits of progress among the peoples of the world. Inequity in the distribution of risks for health and disease is a finding that comes on and on again in real life and in the literature. Inequity in disease burden is clearly related to poverty and the eradication of poverty is the mission for every government and international assistance organisations. Development is also not only a precondition for justice but for peace and stability. Health is seen more and more as preceding development and not only as a consequence of wealth. Therefore many things can and must be done in health to achieve development and of course, equity. This concept has been crucial in the new orientation of WHO and our agency is working hard on its promotion at every level. Vaccines are with us as a simple and effective tool for two centuries. The research and development of new vaccines and all in the underlining knowledge has been much faster than its utilization and there is a huge gap to fill in accessibility and actual coverage. World Health Organization (WHO) has been involved all its life in the promotion of disease control and eradication through the use of immunisation techniques. Presently we are part of GAVI and our Vaccines and Biologicals Department has undergone an important modernisation in order to achieve better performance in pursuing three main objectives: Innovation, Immunisation Systems improvement and Accelerated Disease Control. Therefore in order to walk at a faster pace in the better utilisation of vaccines as a tool for equity, we must join forces and participate actively in all the initiatives that are underway.

Hydrodynamic modelling of stress

This work is a qualitative study of an organism's physiological adaptative response to stress. The experimental data were selected from a previous study leading to the conclusion that stress may be considered as a topological retraction within a vital space that must be more precisely defined. The experimental methodology uses rat poisoning by neurotoxins. The control parameter is the intensity of the toxic doses. Measured parameters are the animals' survival rate and the kinetics of cerebral acetylcholinesterase activity. The results, when expressed as a function of the inverted doses, show a characteristic evolution. The pattern of the curve closely resembles a vortex profile. This analogy is studied more extensively in both the physical and biological domains. These findings help to clarify the concept of biological stress which presents the same vectorial properties as hydrodynamic vorticity. In particular, the dissipation of stress and the dissipation of vorticity seem to obey the same laws. This observation is valid for both diffusion and convection processes. The decompensation phase of stress could be compared with the instability and turbulence in flows. Our approach in this paper is mainly to establish a general and phenomenological description of the stress response fitting experimental observations.

Vaccination of patients with chronic myelogenous leukemia with bcr-abl oncogene breakpoint fusion peptides generates specific immune responses

Chronic myelogenous leukemia (CML) presents a unique opportunity to develop therapeutic strategies using vaccination against a truly tumor-specific antigen that is also the oncogenic protein required for neoplasia. CML is characterized by the t(9;22) that results in the bcr-abl fusion oncogene and in the expression of a chimeric protein product p210. Previously we have shown that peptides derived from amino acid sequences crossing the b3a2 fusion breakpoint in p210 elicit class I restricted cytotoxic T lymphocytes and class II responses, respectively, in vitro. Such sequences may thus comprise absolutely tumor-specific antigens in a peptide-based vaccine. We evaluated the safety and immunogenicity of a multidose, bcr-abl breakpoint peptide vaccine in 12 adults with chronic-phase CML. Cohorts of 3 patients each received either 50 microg, 150 microg, 500 microg, or 1500 microg total peptide mixed with 100 microg QS-21 as an immunological adjuvant. Delayed-type hypersensitivity (DTH), humoral responses, and unprimed ex vivo autologous proliferation ((3)H-thymidine incorporation) and cytotoxicity (chromium-51 release) responses were measured. All 68 vaccinations were well tolerated without significant adverse effects. In 3 of the 6 patients treated at the 2 highest dose levels of vaccine, peptide-specific, T-cell proliferative responses (n = 3) and/or DTH responses (n = 2) were generated that lasted up to 5 months after vaccination. Cytotoxic T lymphocytes have not been identified. In conclusion, a tumor-specific, bcr-abl derived peptide vaccine can be safely administered to patients with chronic-phase CML and can elicit a bcr-abl peptide-specific immune response despite the presence of active disease in these patients and approximately 10(12) leukemia cells. (Blood. 2000;95:1781-1787)

Differentiating Taenia solium and Taenia saginata infections by simple hematoxylin-eosin staining and PCR-restriction enzyme analysis

Species-specific identification of human tapeworm infections is important for public health purposes, because prompt identification of Taenia solium carriers may prevent further human cysticercosis infections (a major cause of acquired epilepsy). Two practical methods for the differentiation of cestode proglottids, (i) routine embedding, sectioning, and hematoxylin-eosin (HE) staining and (ii) PCR with restriction enzyme analysis (PCR-REA), were tested on samples from 40 individuals infected with T. solium (n = 34) or Taenia saginata (n = 6). Microscopic examination of HE staining of sections from 24 cases, in which conserved proglottids were recovered, clearly revealed differences in the number of uterine branches. Distinct restriction patterns for T. solium and T. saginata were observed when the PCR products containing the ribosomal 5.8S gene plus internal transcribed spacer regions were digested with either AluI, DdeI, or MboI. Both HE histology and PCR-REA are useful techniques for differentiating T. solium from T. saginata. Importantly, both techniques can be used in zones of endemicity. HE histology is inexpensive and is currently available in most regions of endemicity, and PCR-REA can be performed in most hospital centers already performing PCR without additional equipment or the use of radioactive material.

The identification of Wos2, a p23 homologue that interacts with Wee1 and Cdc2 in the mitotic control of fission yeasts

The Wee1 kinase inhibits entry into mitosis by phosphorylation of the Cdc2 kinase. Searching for multicopy suppressors that abolish this inhibition in the fission yeast, we have identified a novel gene, here named wos2, encoding a protein with significant homology to human p23, an Hsp90-associated cochaperone. The deletion mutant has a modest phenotype, being heat-shock sensitive. Using antibodies raised against bacterially produced protein, we determined that Wos2 is very abundant, ubiquitously distributed in the yeast cell, and its expression dropped drastically as cells entered into early stationary phase, indicating that its function is associated with cell proliferation. In proliferating cells, the amount of Wos2 protein was not subjected to cell cycle regulation. However, in vitro assays demonstrated that this Hsp90 cochaperone is potentially regulated by phosphorylation. In addition to suppressing Wee1 activity, overproduction of Wos2 displayed synthetic lethality with Cdc2 mutant proteins, indicating that this Hsp90 cochaperone functionally interacts with Cdc2. The level of Cdc2 protein and its associated H1 kinase activity under synthetic lethal conditions suggested a regulatory role for this Wos2-Cdc2 interaction. Hsp90 complexes are required for CDK regulation; the synergy found between the excess of Wos2 and a deficiency in Hsp90 activity suggests that Wos2 could specifically interfere with the Hsp90-dependent regulation of Cdc2. In vitro analysis indicated that the above genetic interactions could take place by physical association of Wos2 with the single CDK complex of the fission yeast. Expression of the budding yeast p23 protein (encoded by the SBA1 gene) in the fission yeast indicated that Wos2 and Sba1 are functionally exchangeable and therefore that properties described here for Wos2 could be of wide significance in understanding the biological function of cochaperone p23 in eukaryotic cells.

A phase I trial of humanized monoclonal antibody HuM195 (anti-CD33) with low-dose interleukin 2 in acute myelogenous leukemia

HuM195 is a recombinant humanized IgG1 monoclonal antibody reactive with CD33, a Mr 67,000 glycoprotein expressed on early myeloid progenitor cells and myeloid leukemia cells. HuM195 has been shown to rapidly target and saturate acute myeloid leukemia (AML) cells after i.v. infusion into patients and is capable of mediating antibody-dependent cellular cytotoxicity. This activity is enhanced in vitro when natural killer (NK) effector cells are preincubated with low concentrations of interleukin 2 (IL-2). Previous Phase I trials of HuM195 in patients with relapsed AML demonstrated safety and attainment of complete responses, but significant antileukemic activity appears limited to patients with low leukemia tumor burdens. Therefore, in the present trial, we sought to determine whether low-dose IL-2 could safely enhance the numbers of NK cells and therefore the cytotoxic capability of HuM195 via presumptive NK cell antibody-dependent cellular cytotoxicity in vivo against myeloid leukemia cells. Thirteen patients with relapsed or refractory AML and one patient with advanced myelodysplastic syndrome were treated with 0.6x10(6) IU/m2 of s.c. IL-2 daily for 35 days. Starting on day 15, patients received twice weekly i.v. infusions of HuM195 (3.0 mg/m2) for 3 weeks. Immediately after the HuM195 infusion, the patients received IL-2 i.v. infusions over 2 h at one of three escalating dose levels of 0.5x10(6), 1.0x10(6), and 2.0x10(6) IU/m2. Peripheral blood mononuclear cells were quantitated and immunophenotyped by flow cytometry. Safety, tolerability, bone marrow mononuclear cell morphology, and immunophenotype, as well as responses were assessed. Of the 14 patients who entered the study, 10 were able to complete at least one cycle of therapy. Adverse effects to the s.c. IL-2 were relatively mild and included erythema and induration of the skin at the injection site and low-grade fever. Toxicity from the sequential HuM195 and i.v. IL-2 infusions included nausea, rigors, and fever. Toxicity was IL-2 dose related with dose-limiting toxicity seen at the 2.0x10(6) IU/m2 dose level. Three patients had stable disease at the completion of the first cycle and went on to receive a second cycle of treatment. CD3-positive, CD56-positive, and CD33-positive cells were generally found to significantly decrease immediately after each administration of i.v. IL-2 and HuM195. CD56-expressing cells increased in 6 of 10 patients from the beginning to the end of therapy. Among the 10 evaluable patients, 2 patients had significant decreases in the percentage of blasts in the bone marrow (one of which achieved a complete bone marrow remission), 5 patients had stable levels of bone marrow blasts, and 3 had progression of disease on therapy. The combination of IL-2 and HuM195 shows modest biological activity and clinical antileukemic activity but also produced significant toxicity.

Isolation of ani-hepatotoxic principle form the juice of Ecballium elaterium

The antihepatotoxic activity of elaterium (dried juice of the fruits of Ecballium elaterium, Cucurbitaceae) and cucurbitacin B (isolated from the juice) was studied against CCl4-induced hepatotoxicity. Pre- and posttreatment with elaterium and cucurbitacin B reduced CCl4-hepatotoxicity, as shown reduction in the anormally increased sGPT levels. Posttreatment caused a significant reduction in the degree of steatosis observed inthe control group, treated only with CCl4. In conclusion, elaterium and cucurbitacin B had preventive and curative effects against CCl4-induced hepatotoxicity.

Translational control of the cdc25 cell cycle phosphatase: a molecular mechanism coupling mitosis to cell growth

The eukaryotic translation initiation factor 4A (eIF4A) is an RNA helicase required for translation initiation of eukaryotic mRNAs. By engineering fission yeast mutants with diminished eIF4A activity, we have found that translation of cdc25 mRNAs (a dosage-dependent activator of mitosis in all eukaryotic cells) is particularly sensitive to limitations of protein synthesis mediated by limited eIF4A activity. Genetic and biochemical analysis indicated that a rate-limited translation initiation of cdc25 mRNAs, exerted throughout its unusual 5′ untranslated leader, acts as a molecular sensor to ensure that a minimum cell mass (protein synthesis) is attained before mitosis occurs. The Cdc13 cyclin B is also among the limited pool of proteins whose translation is sensitive to reduced translation initiation activity. Interestingly, the 5′ leader sequences of cdc25 and cdc13 mRNAs have conserved features which are unusual in other yeast mRNAs, suggesting that common mechanisms operate in the expression of these two key mitotic activators at the translational level.

Nonlinearly limited saturable-absorber mode locking of an erbium fiber laser

We describe an erbium fiber laser that is passively mode locked by a novel, precision antireflection-coated semiconductor saturable-absorber mirror that incorporates an additional two-photon absorber. It is shown that passive mode locking evolves from a Q-switching instability. The results are achieved by use of saturable absorbers that provide a large (15%) nonlinear (saturable) loss. Exploiting two-photon absorption can substantially reduce the peak power of the Q-switched pulses, which results in improved reliability of the laser. Moreover, two-photon absorption can be used to produce an optimal stability range for saturable-absorber mode locking.

Osmotic response element is required for the induction of aldose reductase by tumor necrosis factor-alpha

Induction of aldose reductase (AR) was observed in human cells treated with tumor necrosis factor-alpha (TNF-alpha). AR protein expression increased severalfold in human liver cells after 1 day of exposure to 100 units/ml TNF-alpha. An increase in AR transcripts was also observed in human liver cells after 3 h of TNF-alpha treatment, reaching a maximum level of 11-fold at 48 h. Among the three inflammatory cytokines: TNF-alpha, interleukin-1, and interferon-gamma, TNF-alpha (100 units/ml) gave the most induction of AR. Differences in the pattern of AR induction were observed in human liver, lens, and retinal pigment epithelial cells with increasing concentrations of TNF-alpha. A similar pattern of AR promoter response was observed between TNF-alpha and osmotically stressed human liver cells. The deletion of the osmotic response element (ORE) abolished the induction by TNF-alpha and osmotic stress. A point mutation that converts ORE to a nuclear factor-kappaB (NF-kappaB) sequence abolished the osmotic response but maintained the TNF-alpha response. Electrophoretic gel mobility shift assays showed two NF-kappaB proteins, p50 and p52, capable of binding ORE sequence, and gel shift Western assay detected NF-kappaB proteins p50 and p65 in the ORE complex. Inhibitors of NF-kappaB signaling, lactacystin, and MG132 abolished the AR promoter response to TNF-alpha.

Genetic interactions between Hsp90 and the Cdc2 mitotic machinery in the fission yeast Schizosaccharomyces pombe

In Schizosaccharomyces pombe, wee1 encodes a tyrosine kinase that inhibits entry into mitosis by phophorylating Cdc2, the universal cyclin-dependent kinase (Cdk) that regulates the G2/M transition in all eukaryotic cells. A search for suppressors of the G2 arrest caused by overexpression of weel led to the isolation of a new allele of swo1 (named swo1-w1), the gene coding for chaperone Hsp90, which is required to stabilise Weel. The swo1-w1 allele carries a glycine to aspartic acid substitution at amino acid 155 that results in a partial loss of Hsp90 function. Cells bearing the swo1-w1 mutation in combination with the point mutation cdc2-33 or cdc2-M26 showed severe mitotic defects. Genetic interactions were not observed in combination with point mutations in other cdc genes, suggesting that Cdc2 specifically interacts with Hsp90. This synthetic lethal swo1-w1 cdc2-33 (or cdc2-M26) strain had normal levels of Cdc2 protein and histone H1 phosphorylation activity, indicating that Hsp90 is required to enable Cdc2 to interact with its mitotic substrates or regulators, rather than for its proper folding or stabilisation. In a wild-type background, swo1-w1 mutant cells were sensitive to temperature as well as to other stress agents, such as KCI, ethanol and formamide. Under these stressful growth conditions, the swo1-w1 cells displayed anaphase B arrest and aberrant septation patterns, indicating that a subset of proteins involved in mitosis and cytokinesis is highly dependent on chaperone Hsp90 for function.