Systematic genetic analysis with ordered arrays of yeast deletion mutants

In Saccharomyces cerevisiae, more than 80% of the approximately 6200 predicted genes are nonessential, implying that the genome is buffered from the phenotypic consequences of genetic perturbation. To evaluate function, we developed a method for systematic construction of double mutants, termed synthetic genetic array (SGA) analysis, in which a query mutation is crossed to an array of approximately 4700 deletion mutants. Inviable double-mutant meiotic progeny identify functional relationships between genes. SGA analysis of genes with roles in cytoskeletal organization (BNI1, ARP2, ARC40, BIM1), DNA synthesis and repair (SGS1, RAD27), or uncharacterized functions (BBC1, NBP2) generated a network of 291 interactions among 204 genes. Systematic application of this approach should produce a global map of gene function.

ICP34.5 deleted herpes simplex virus with enhanced oncolytic, immune stimulating, and anti-tumour properties

Herpes simplex virus type-1 (HSV1) in which the neurovirulence factor ICP34.5 is inactivated has been shown to direct tumour-specific cell lysis in several tumour models. Such viruses have also been shown to be safe in Phase I clinical trials by intra-tumoral injection in glioma and melanoma patients. Previous work has used serially passaged laboratory isolates of HSV1 which we hypothesized may be attenuated in their lytic capability in human tumour cells as compared to more recent clinical isolates. To produce ICP34.5 deleted HSV with enhanced oncolytic potential, we tested two clinical isolates. Both showed improved cell killing in all human tumour cell lines tested compared to a laboratory strain (strain 17+). ICP34.5 was then deleted from one of the clinical isolate strains (strain JS1). Enhanced tumour cell killing with ICP34.5 deleted HSV has also been reported by the deletion of ICP47 by the up-regulation of US11 which occurs following this mutation. Thus to further improve oncolytic properties, ICP47 was removed from JS1/ICP34.5-. As ICP47 also functions to block antigen processing in HSV infected cells, this mutation was also anticipated to improve the immune stimulating properties of the virus. Finally, to provide viruses with maximum oncolytic and immune stimulating properties, the gene for human or mouse GM-CSF was inserted into the JS1/34.5-/47- vector backbone. GM-CSF is a potent immune stimulator promoting the differentiation of progenitor cells into dendritic cells and has shown promise in clinical trials when delivered by a number of means. Combination of GM-CSF with oncolytic therapy may be particularly effective as the necrotic cell death accompanying virus replication should serve to effectively release tumour antigens to then induce a GM-CSF-enhanced immune response. This would, in effect, provide an in situ, patient-specific, anti-tumour vaccine. The viruses constructed were tested in vitro in human tumour cell lines and in vivo in mice demonstrating significant anti-tumour effects. These were greatly improved compared to viruses not containing each of the modifications described. In vivo, both injected and non-injected tumours showed significant shrinkage or clearance and mice were protected against re-challenge with tumour cells. The data presented indicate that JS1/ICP34.5-/ICP47-/GM-CSF acts as a powerful oncolytic agent which may be appropriate for the treatment of a number of solid tumour types in man.

Phosphorylation of the MAP kinase ERK2 promotes its homodimerization and nuclear translocation

The MAP kinase ERK2 is widely involved in eukaryotic signal transduction. Upon activation it translocates to the nucleus of the stimulated cell, where it phosphorylates nuclear targets. We find that nuclear accumulation of microinjected ERK2 depends on its phosphorylation state rather than on its activity or on upstream components of its signaling pathway. Phosphorylated ERK2 forms dimers with phosphorylated and unphosphorylated ERK2 partners. Disruption of dimerization by mutagenesis of ERK2 reduces its ability to accumulate in the nucleus, suggesting that dimerization is essential for its normal ligand-dependent relocalization. The crystal structure of phosphorylated ERK2 reveals the basis for dimerization. Other MAP kinase family members also form dimers. The generality of this behavior suggests that dimerization is part of the mechanism of action of the MAP kinase family.

Whole-genome association study of bipolar disorder

We performed a genome-wide association scan in 1461 patients with bipolar (BP) 1 disorder, 2008 controls drawn from the Systematic Treatment Enhancement Program for Bipolar Disorder and the University College London sample collections with successful genotyping for 372,193 single nucleotide polymorphisms (SNPs). Our strongest single SNP results are found in myosin5B (MYO5B; P=1.66 x 10(-7)) and tetraspanin-8 (TSPAN8; P=6.11 x 10(-7)). Haplotype analysis further supported single SNP results highlighting MYO5B, TSPAN8 and the epidermal growth factor receptor (MYO5B; P=2.04 x 10(-8), TSPAN8; P=7.57 x 10(-7) and EGFR; P=8.36 x 10(-8)). For replication, we genotyped 304 SNPs in family-based NIMH samples (n=409 trios) and University of Edinburgh case-control samples (n=365 cases, 351 controls) that did not provide independent replication after correction for multiple testing. A comparison of our strongest associations with the genome-wide scan of 1868 patients with BP disorder and 2938 controls who completed the scan as part of the Wellcome Trust Case-Control Consortium indicates concordant signals for SNPs within the voltage-dependent calcium channel, L-type, alpha 1C subunit (CACNA1C) gene. Given the heritability of BP disorder, the lack of agreement between studies emphasizes that susceptibility alleles are likely to be modest in effect size and require even larger samples for detection.

5-Aminosalicylic acid enema in the treatment of distal ulcerative colitis, proctosigmoiditis, and proctitis

The efficacy and safety of 4-g 5-aminosalicylic acid enemas were assessed in 153 patients with ulcerative colitis involving up to 50 cm of distal colon. Seventy-six patients received active medication and 77 received a placebo. There were 20 dropouts (6 in the active group and 14 in the placebo group) during the study because of insufficient efficacy. After 6 wk of therapy, 48 of the 76 patients (63%) receiving 5-aminosalicylic acid were considered to be "much improved" by the study physician compared to 22 of the 77 patients (29%) on placebo (p = 0.001). A disease activity index based on patient symptoms and sigmoidoscopic appearance was used to assess efficacy. Mean disease activity index declined 55% for patients on 5-aminosalicylic acid and 24% for patients on placebo (p = 0.0001). Analysis of subgroups indicated that patients most likely to respond were those with disease confined to the 20-40 cm from the anus. Response was not affected by concurrent sulfasalazine, but patients requiring concurrent oral steroids had a diminished response. Rapid onset of efficacy was shown by a significant reduction in rectal bleeding within 3 days of treatment initiation. 5-Aminosalicylic acid enemas are well tolerated and are of benefit in the treatment of ulcerative colitis confined to the distal colon.

Fluconazole prophylaxis against fungal colonization and infection in preterm infants

BACKGROUND

Invasive fungal infection is associated with substantial morbidity and mortality in preterm infants. We evaluated the efficacy of prophylactic fluconazole in preventing fungal colonization and invasive infection in extremely-low-birth-weight infants.

METHODS

We conducted a prospective, randomized, double-blind clinical trial over a 30-month period in 100 preterm infants with birth weights of less than 1000 g. The infants were randomly assigned during the first five days of life to receive either intravenous fluconazole or placebo for six weeks. We obtained weekly surveillance cultures from all patients.

RESULTS

The 50 infants randomly assigned to fluconazole and the 50 control infants were similar in terms of birth weight, gestational age at birth, and base-line risk factors for fungal infection. During the six-week treatment period, fungal colonization was documented in 30 infants in the placebo group (60 percent) and 11 infants in the fluconazole group (22 percent; difference in risk, 0.38; 95 percent confidence interval, 0.18 to 0.56; P=0.002). Invasive fungal infection with positive growth of fungal isolates from the blood, urine, or cerebrospinal fluid developed in 10 infants in the placebo group (20 percent) and none of the infants in the fluconazole group (difference in risk, 0.20; 95 percent confidence interval, 0.04 to 0.36; P=0.008). The sensitivities of the fungal isolates to fluconazole did not change during the study, and no adverse effects of the fluconazole therapy were documented.

CONCLUSIONS

Prophylactic administration of fluconazole during the first six weeks of life is effective in preventing fungal colonization and invasive fungal infection in infants with birth weights of less than 1000 g.

Novel quantitative method for determination of molecular species of phospholipids and diglycerides

A novel method is described for the quantitative analysis of subclasses (alk-1-enylacyl, alkylacyl, and diacyl types) and molecular species within each subclass of glycerophosphatides. Diradylglycerols from phospholipase C hydrolysis of the phospholipids are converted to benzoate derivatives, the benzoates are separated into their respective subclasses by thin-layer chromatography, and quantitated by measuring absorbance at 230 nm. Molecular species within individual subclasses are separated using a combination of argentation thin-layer chromatography and reversed-phase high-performance liquid chromatography with direct, on-line quantitation at 230 nm. We applied the method to the analysis of ethanolamine phosphatides from beef brain and were able to quantitate the three diradylglycerol subclasses (alk-1-enylacyl, alkylacyl, and diacyl types) as well as ca. 29 molecular species within each of these subclasses. This new quantitative approach for the analysis of specific molecular species of glycerolipids should be applicable to studies involving a variety of biologically important lipids, such as phosphatidylcholine, phosphatidylinositol, platelet activating factor, plasmalogens, and neutral type glycerolipids including diacylglycerols.

Neurobiology of depression: an integrated view of key findings

AIMS

The objectives of the present review were to summarise the key findings from the clinical literature regarding the neurobiology of major depressive disorder (MDD) and their implications for maximising treatment outcomes. Several neuroanatomical structures in the prefrontal and limbic areas of the brain are involved in affective regulation. In patients with MDD, alterations in the dynamic patterns of activity among these structures have profound implications for the pathogenesis of this illness.

DISCUSSION

The present work reviews the evidence for the progressive nature of MDD along with associated changes in neuroanatomical structure and function, especially for the hippocampus. The role of glucocorticoids, inflammatory cytokines and brain-derived growth factors are discussed as mediators of these pathological alterations. From this integrated model, the role of antidepressant therapy in restoring normative processes is examined along with additional treatment guidelines.

CONCLUSION

Major depressive disorder is an illness with significant neurobiological consequences involving structural, functional and molecular alterations in several areas of the brain. Antidepressant pharmacotherapy is associated with restoration of the underlying physiology. Clinicians are advised to intervene with MDD using an early, comprehensive treatment approach that has remission as the goal.

Codon usage can affect efficiency of translation of genes in Escherichia coli

By inserting synthetic oligonucleotides into a highly expressed gene in E. coli it has been shown that unfavourable codon usage can reduce the maximum translation rate of a protein. However, in the case of the codon used (AGG), a significant effect on translation was only seen at very high transcription rates from a gene containing multiple copies of the unfavourable codon.

NEAR at eros: imaging and spectral results

Eros is a very elongated (34 kilometers by 11 kilometers by 11 kilometers) asteroid, most of the surface of which is saturated with craters smaller than 1 kilometer in diameter. The largest crater is 5.5 kilometers across, but there is a 10-kilometer saddle-like depression with attributes of a large degraded crater. Surface lineations, both grooves and ridges, are prominent on Eros; some probably exploit planes of weakness produced by collisions on Eros and/or its parent body. Ejecta blocks (30 to 100 meters across) are abundant but not uniformly distributed over the surface. Albedo variations are restricted to the inner walls of certain craters and may be related to downslope movement of regolith. On scales of 200 meters to 1 kilometer, Eros is more bland in terms of color variations than Gaspra or Ida. Spectra (800 to 2500 nanometers) are consistent with an ordinary chondrite composition for which the measured mean density of 2.67 +/- 0.1 grams per cubic centimeter implies internal porosities ranging from about 10 to 30 percent.

Genomic organization and partial duplication of the human alpha7 neuronal nicotinic acetylcholine receptor gene (CHRNA7)

The human alpha7 neuronal nicotinic acetylcholine receptor gene (HGMW-approved symbol CHRNA7) has been characterized from genomic clones. The gene is similar in structure to the chick alpha7 gene with 10 exons and conserved splice junction positions. The size of the human gene is estimated to be larger than 75 kb. A putative promoter 5' of the translation start in exon 1 has been cloned and sequenced. The promoter region lacks a TATA box and has a high GC content (77%). Consensus Sp1, AP-2, Egr-1, and CREB transcription factor binding sites appear to be conserved between bovine and human genes. The alpha7 nAChR gene was found to be partially duplicated, with both loci mapping to the chromosome 15q13 region. A yeast artificial chromosome contig was constructed over a genetic distance of 5 cM that includes both alpha7 loci and the region between them. Four novel exons are described, located in genomic clones containing the partially duplicated gene. The duplicated sequences, including the novel exons, are expressed in human brain.

Short chain fatty acid rectal irrigation for left-sided ulcerative colitis: a randomised, placebo controlled trial

BACKGROUND

Short chain fatty acid (SCFA) deficiency is associated with colitis in animals and humans, and the mucosal metabolism of these compounds is decreased in ulcerative colitis.

AIMS

To assess the efficacy of topical SCFA treatment in ulcerative colitis.

PATIENTS AND METHODS

103 patients with distal ulcerative colitis were entered into a six week, double-blind, placebo controlled trial of rectal SCFA twice daily; patients who were unchanged on placebo were offered SCFA in an open-label extension trial.

RESULTS

Of the 91 patients completing the trial, more patients in the SCFA treated than in the placebo treated group improved (33% v 20%, p = 0.14, NS). Those on SCFA also had larger, but statistically non-significant, reductions in every component of their clinical and histological activity scores. In patients with a relatively short current episode of colitis (< 6 months, n = 42), more responded to SCFA than to placebo (48% v 18%, p = 0.03). These patients also had larger, but statistically non-significant, decreases in their clinical activity index (p = 0.08 v placebo). Every patient who improved used at least five of six of the prescribed rectal SCFA irrigations, whereas only 37% who did not improve were as compliant. In the open-label extension trial, 65% improved on SCFA; these patients also had significant reductions (p < 0.02) in their clinical and histological activity scores.

CONCLUSIONS

Although SCFA enemas were not of therapeutic value in this controlled trial, the results suggest efficacy in subsets of patients with distal ulcerative colitis including those with short active episodes. Prolonged contact with rectal mucosa seems to be necessary for therapeutic benefit.

Clusterin regulates β-amyloid toxicity via Dickkopf-1-driven induction of the wnt-PCP-JNK pathway

Although the mechanism of Aβ action in the pathogenesis of Alzheimer's disease (AD) has remained elusive, it is known to increase the expression of the antagonist of canonical wnt signalling, Dickkopf-1 (Dkk1), whereas the silencing of Dkk1 blocks Aβ neurotoxicity. We asked if clusterin, known to be regulated by wnt, is part of an Aβ/Dkk1 neurotoxic pathway. Knockdown of clusterin in primary neurons reduced Aβ toxicity and DKK1 upregulation and, conversely, Aβ increased intracellular clusterin and decreased clusterin protein secretion, resulting in the p53-dependent induction of DKK1. To further elucidate how the clusterin-dependent induction of Dkk1 by Aβ mediates neurotoxicity, we measured the effects of Aβ and Dkk1 protein on whole-genome expression in primary neurons, finding a common pathway suggestive of activation of wnt-planar cell polarity (PCP)-c-Jun N-terminal kinase (JNK) signalling leading to the induction of genes including EGR1 (early growth response-1), NAB2 (Ngfi-A-binding protein-2) and KLF10 (Krüppel-like factor-10) that, when individually silenced, protected against Aβ neurotoxicity and/or tau phosphorylation. Neuronal overexpression of Dkk1 in transgenic mice mimicked this Aβ-induced pathway and resulted in age-dependent increases in tau phosphorylation in hippocampus and cognitive impairment. Furthermore, we show that this Dkk1/wnt-PCP-JNK pathway is active in an Aβ-based mouse model of AD and in AD brain, but not in a tau-based mouse model or in frontotemporal dementia brain. Thus, we have identified a pathway whereby Aβ induces a clusterin/p53/Dkk1/wnt-PCP-JNK pathway, which drives the upregulation of several genes that mediate the development of AD-like neuropathologies, thereby providing new mechanistic insights into the action of Aβ in neurodegenerative diseases.

Effect of increasing doses of hypertonic saline on mucociliary clearance in patients with cystic fibrosis

BACKGROUND

Patients with cystic fibrosis are known to have decreased mucociliary clearance. It has previously been shown that inhalation of a 7.0% solution of hypertonic saline significantly improved mucociliary clearance in a group of adult patients with cystic fibrosis. The aim of this study was to measure the response to increasing concentrations of inhaled hypertonic saline.

METHODS

Ten patients (seven men) of mean (SE) age 22 (4) years and mean forced expiratory volume in one second (FEV1) 52.0 (6.7)% predicted completed the study. Mucociliary clearance was measured using a radioaerosol technique for 90 minutes after the interventions which comprised 0.9% NaCl + voluntary cough (control), 3.0% NaCl, 7.0% NaCl, and 12% NaCl.

RESULTS

There was a significant increase in the amount of activity cleared from the right lung with all concentrations of hypertonic saline (HS) compared with control. The amount cleared at 90 minutes on the control day was 12.7% (95% confidence interval (CI) 9.8 to 17.2) compared with 19.7% (95% CI 13.6 to 29.5) for 3% HS, 23.8% (95% CI 15.9 to 36.7) for 7% HS and 26.0% (95% CI 19.8 to 35.9) for 12% HS. The improvement in mucociliary clearance was not solely due to coughing as the number of coughs recorded on the control day exceeded that recorded on any other day. The hypertonic saline did not induce a clinically significant change in FEV1.

CONCLUSIONS

Within the range of concentrations examined in this study, the effect of hypertonic saline appears to be dose dependent. Inhalation of hypertonic saline remains a potentially useful treatment for patients with cystic fibrosis.

Understanding triclabendazole resistance

Triclabendazole (TCBZ) has been the drug of choice to treat liver fluke infections in livestock for >20 years, due to its high activity against both adult and juvenile flukes. More recently, it has been used successfully to treat human cases of fascioliasis. Resistance to TCBZ first appeared in the field in Australia in the mid-1990s. Since then, resistance has been reported from a number of countries throughout Europe: Ireland, Scotland, Wales, Spain and The Netherlands. The heavy reliance on a single drug puts treatment strategies for fascioliasis at risk. Should resistance develop further, the prospect is an alarming one. This review will present an overview of progress in understanding the mechanism of resistance to TCBZ, examining possible changes in the target molecule, in drug influx/efflux mechanisms and in the metabolism of TCBZ by the fluke. The review will also consider ways to deal with resistance, covering drug-oriented options such as: the use of alternative drugs, drug combinations and the search for new compounds.

A comparison of silver stain and SYPRO Ruby Protein Gel Stain with respect to protein detection in two-dimensional gels and identification by peptide mass profiling

Proteomic projects are often focused on the discovery of differentially expressed proteins between control and experimental samples. Most laboratories choose the approach of running two-dimensional (2-D) gels, analyzing them and identifying the differentially expressed proteins by in-gel digestion and mass spectrometry. To date, the available stains for visualizing proteins on 2-D gels have been less than ideal for these projects because of poor detection sensitivity (Coomassie blue stain) or poor peptide recovery from in-gel digests and mass spectrometry (silver stain), unless extra destaining and washing steps are included in the protocol. In addition, the limited dynamic range of these stains has made it difficult to rigorously and reliably determine subtle differences in protein quantities. SYPRO Ruby Protein Gel Stain is a novel, ruthenium-based fluorescent dye for the detection of proteins in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) gels that has properties making it well suited to high-throughput proteomics projects. The advantages of SYPRO Ruby Protein Gel Stain relative to silver stain demonstrated in this study include a broad linear dynamic range and enhanced recovery of peptides from in-gel digests for matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry.

The landing of the NEAR-Shoemaker spacecraft on asteroid 433 Eros

The NEAR-Shoemaker spacecraft was designed to provide a comprehensive characterization of the S-type asteroid 433 Eros (refs 1,2,3), an irregularly shaped body with approximate dimensions of 34 x 13 x 13 km. Following the completion of its year-long investigation, the mission was terminated with a controlled descent to its surface, in order to provide extremely high resolution images. Here we report the results of the descent on 12 February 2001, during which 70 images were obtained. The landing area is marked by a paucity of small craters and an abundance of 'ejecta blocks'. The properties and distribution of ejecta blocks are discussed in a companion paper. The last sequence of images reveals a transition from the blocky surface to a smooth area, which we interpret as a 'pond'. Properties of the 'ponds' are discussed in a second companion paper. The closest image, from an altitude of 129 m, shows the interior of a 100-m-diameter crater at 1-cm resolution.

High-throughput profiling of the mitochondrial proteome using affinity fractionation and automation

Recent studies have demonstrated the need for complementing cellular genomic information with specific information on expressed proteins, or proteomics, since the correlation between the two is poor. Typically, proteomic information is gathered by analyzing samples on two-dimensional gels with the subsequent identification of specific proteins of interest by using trypsin digestion and mass spectrometry in a process termed peptide mass fingerprinting. These procedures have, as a rule, been labor-intensive and manual, and therefore of low throughput. The development of automated proteomic technology for processing large numbers of samples simultaneously has made the concept of profiling entire proteomes feasible at last. In this study, we report the initiation of the (eventual) complete profile of the rat mitochondrial proteome by using high-throughput automated equipment in combination with a novel fractionation technique using minispin affinity columns. Using these technologies, approximately one hundred proteins could be identified in several days. In addition, separate profiles of calcium binding proteins, glycoproteins, and hydrophobic or membrane proteins could be generated. Because mitochondrial dysfunction has been implicated in numerous diseases, such as cancer, Alzheimer's disease and diabetes, it is probable that the identification of the majority of mitochondrial proteins will be a beneficial tool for developing drug and diagnostic targets for associated diseases.

Effect of hypertonic saline, amiloride, and cough on mucociliary clearance in patients with cystic fibrosis

In patients with cystic fibrosis (CF), dehydration of airway secretions leads to a decrease in mucociliary clearance (MCC). We examined the acute effect of MCC of a single administration by aerosolization of hypertonic saline (7%) (HS), amiloride (0.3% in 0.12% NaCl) (AML) and a combination of AML and HS (AML + HS) in 12 patients with CF using a radioaerosol technique. Isotonic saline [0.9%] (IS) was used as a control solution. As both the AML and HS solutions induced cough in some patients, the last nine patients studied also underwent a cough clearance day. This was to eliminate the possible confounding effect of cough on MCC measurement. Patients ranged from 18 to 28 yr (mean +/- SD, 22 +/- 3) with an FEV1 of 27 to 112% predicted (61 +/- 30%). Following deposition of the radioaerosol, baseline clearance was assessed for 30 min. This was followed by a 30-min intervention period. Assessment of post-intervention clearance for a further 30 min was then performed. Comparison of the amount of radioaerosol cleared from the right lung was made at 60 min (%C60) and 90 min (%C90) using repeated measures ANOVA. The percent cleared at 60 and 90 min was significantly increased with HS (%C60 = 26.5%, %C90 = 29.4%) and the combination of AML + HS (%C60 = 23.1%, %C90 = 27.4%) compared with both IS (%C60 = 14.7%, %C90 = 17.5%) and COUGH (%C60 = 18.0%, %C90 = 19.5%), p < 0.01. Inhalation of hypertonic saline is a potentially useful treatment in patients with cystic fibrosis.

NEAR's flyby of 253 mathilde: images of a C asteroid

On 27 June 1997, the Near Earth Asteroid Rendezvous (NEAR) spacecraft flew within 1212 kilometers of asteroid 253 Mathilde. Mathilde is an irregular, heavily cratered body measuring 66 kilometers by 48 kilometers by 46 kilometers. The asteroid's surface is dark (estimated albedo between 0.035 and 0.050) and similar in color to some CM carbonaceous chondrites. No albedo or color variations were detected. The volume derived from the images and the mass from Doppler tracking of the spacecraft yield a mean density of 1.3 +/- 0.2 grams per cubic centimeter, about half that of CM chondrites, indicating a porous interior structure.

Preliminary evaluation of safety and activity of recombinant human interleukin 11 in patients with active Crohn's disease

BACKGROUND & AIMS

Recombinant human interleukin 11 (rhIL-11) is a cytokine with thrombocytopoietic activity and anti-inflammatory and mucosal protective effects. The objectives of this study were to investigate the safety and tolerability of rhIL-11 in patients with Crohn's disease and to explore the effects of dose and schedule on platelet count and Crohn's disease activity.

METHODS

A multicenter, double-masked, placebo-controlled, dose-escalation study of 76 patients with active Crohn's disease was performed. Patients were randomized to receive subcutaneous placebo or rhIL-11 at doses of 5, 16, or 40 microgram. kg-1. wk-1 given 2 or 5 times weekly for 3 weeks. Clinical and laboratory safety data were recorded, and disease activity was measured at each visit.

RESULTS

Subcutaneous injection of rhIL-11 generally was well tolerated. Significantly greater increases in platelet counts were found among patients receiving rhIL-11 40 microgram. kg-1. wk-1 as 2 or 5 weekly doses and 16 microgram. kg-1. week-1 as 5 weekly doses compared with patients receiving placebo (P < 0.05). Patients receiving 16 microgram. kg-1. wk-1 had the highest clinical response rates, with a response seen in 42% of patients (5/12) receiving 5 weekly doses and 33% of patients (4/12) receiving 2 weekly doses, compared with 7% of patients (1/15) receiving placebo.

CONCLUSIONS

Short-term treatment with rhIL-11 is well tolerated in patients with active Crohn's disease. The thrombocytopoietic effect of rhIL-11 seems to be both dose and schedule dependent and may be minimized with retained clinical benefit in Crohn's disease at 16 microgram. kg-1. wk-1 given in 2 equal doses.

Sensitivity of the relative-rate test to taxonomic sampling

Relative-rate tests may be used to compare substitution rates between more than two sequences, which yields two main questions: What influence does the number of sequences have on relative-rate tests and what is the influence of the sampling strategy as characterized by the phylogenetic relationships between sequences? Using both simulations and analysis of real data from murids (APRT and LCAT nuclear genes), we show that comparing large numbers of species significantly improves the power of the test. This effect is stronger if species are more distantly related. On the other hand, it appears to be less rewarding to increase outgroup sampling than to use the single nearest outgroup sequence. Rates may be compared between paraphyletic ingroups and using paraphyletic outgroups, but unbalanced taxonomic sampling can bias the test. We present a simple phylogenetic weighting scheme which takes taxonomic sampling into account and significantly improves the relative-rate test in cases of unbalanced sampling. The answers are thus: (1) large taxonomic sampling of compared groups improves relative-rate tests, (2) sampling many outgroups does not bring significant improvement, (3) the only constraint on sampling strategy is that the outgroup be valid, and (4) results are more accurate when phylogenetic relationships between the investigated sequences are taken into account. Given current limitations of the maximum-likelihood and nonparametric approaches, the relative-rate test generalized to any number of species with phylogenetic weighting appears to be the most general test available to compare rates between lineages.

Carcinogenicity of chloroform in drinking water to male Osborne-Mendel rats and female B6C3F1 mice

The carcinogenic activity of chloroform administered at 0, 200, 400, 900, and 1800 mg/liter in drinking water was studied in male Osborne-Mendel rats and female B6C3F1 mice. A second control group was included in the study and was restricted to the water consumption of the high-dose group. Animals were maintained on study for 104 weeks. Group sizes were adjusted at low doses such that a detectable tumor response would result at the lowest dose if there was a linear relationship with dose, and the higher doses produced responses similar to previous carcinogenesis bioassays of chloroform. The primary finding was that chloroform increased the yield of renal tubular adenomas and adenocarcinomas in male rats in a dose-related manner. For the high-dose group, which corresponded to a time-weighted average dose of 160 mg/kg per day for 104 weeks, there was a 14% incidence of renal tubular adenomas and adenocarcinomas, vs 1% in the control group. This compares to a 24% incidence observed when 180 mg/kg per day of chloroform was administered for 78 weeks in earlier studies. In contrast, chloroform in the drinking water of mice failed to increase the incidence of hepatocellular carcinomas in female B6C3F1 mice. The highest dose group received a time-weighted average dose of 263 mg/kg for 104 weeks, resulting in a 5% combined incidence of hepatocellular adenoma and carcinoma relative to a 6% incidence in the control groups.(ABSTRACT TRUNCATED AT 250 WORDS)