Measurement and determinants of the natural history of liver fibrosis in hepatitis C virus infection: a cross sectional and longitudinal study

INTRODUCTION

The rate of development of liver fibrosis in hepatitis C virus (HCV) infection varies between individuals. This accounts for the variation in duration of progression to cirrhosis. The aims of this study were: (1) to determine whether fibrosis progresses linearly through the grading scales and (2) to identify factors which influence the rate of fibrosis.

METHODS

HCV infected patients who had undergone at least one liver biopsy were identified. Biopsies were scored using the modified HAI (Ishak) and METAVIR systems, which were compared. Patients were treatment naïve at first biopsy. Demographic features were examined for their relationship to fibrosis rate (defined as fibrosis stage/infection duration) using univariate and multivariate analysis. A subgroup of patients with two biopsies was examined to test the assumption that fibrosis progresses in a linear fashion.

RESULTS

A total of 917 patients were included. Male sex (p<0.00001), older age at infection (p</=0.00001), and viral genotype non-1 (p=0.005) were all associated with a rapid rate of fibrosis. On multiple linear regression they accounted for 29.5% of the variability in fibrosis rate (r(2)=0.295). METAVIR and Ishak scores were highly correlated (r=0.935, p<0.0001). In 137 patients who had two biopsies, the predicted probability for an increase of 1 on the fibrosis score was too low to assess linearity.

CONCLUSIONS

Demographic features account for a minority of fibrosis rate variability. The Ishak and METAVIR scoring systems are equivalent. Linearity of fibrosis progression cannot be assessed in biopsies only a few years apart.

Defining senescence and death

This article evaluates features of leaf and flower senescence that are shared with, or are different from, those of other terminal events in plant development. Alterations of plastid structure and function in senescence are often reversible and it is argued that such changes represent a process of transdifferentiation or metaplasia rather than deterioration. It may be that the irreversible senescence of many flowers and some leaves represents the loss of ancestral plasticity during evolution. Reversibility serves to distinguish senescence fundamentally from programmed cell death (PCD), as does the fact that viability is essential for the initiation and progress of cell senescence. Senescence (particularly its timing and location) requires new gene transcription, but the syndrome is also subject to significant post- transcriptional and post-translational regulation. The reversibility of senescence must relate to the plastic, facultative nature of underlying molecular controls. Senescence appears to be cell-autonomous, though definitive evidence is required to substantiate this. The vacuole plays at least three key roles in the development of senescing cells: it defends the cell against biotic and abiotic damage, thus preserving viability, it accumulates metabolites with other functions, such as animal attractants, and it terminates senescence by becoming autolytic and facilitating true cell death. The mechanisms of PCD in plants bear a certain relation to those of apoptosis, and some processes, such as nucleic acid degradation, are superficially similar to aspects of the senescence syndrome. It is concluded that, in terms of physiological components and their controls, senescence and PCD are at best only distantly related.

Cancer-related fatigue--a difference of opinion? Results of a multicentre survey of healthcare professionals, patients and caregivers

The objective of this study was to investigate the perceptions of patients with cancer, their caregivers and healthcare professionals (HCPs) about fatigue and its impact on quality of life. It was a cross-sectional survey, the respondents were patients with cancer attending three UK regional cancer centres (n = 1,370), their informal caregivers (n = 1,370) and a random selection of HCPs (oncologists/nurses/radiographers/haematologists; n = 1,098). The response rates for patients, caregivers and HCPs were 42%, 33% and 34% respectively. Fatigue was reported to affect 56% of patients and to have a considerable impact on quality of life. Caregivers also recognized that fatigue was a common problem, with significant effects on patients' quality of life and impact on themselves. Healthcare professionals recognized that fatigue was a common problem for their patients but overestimated its impact on some aspects of patients' daily lives. Although most HCPs reported that they prescribed/recommended treatment for over half of their patients, only 14% of patients reported receiving any such treatment. The most common advice was to take more rest and relaxation.

CONCLUSIONS

patients with cancer report that fatigue is a common and distressing symptom and the importance of this symptom is generally recognized by both HCPs and lay-carers. Healthcare professionals need more information about the effectiveness of existing interventions for cancer-related fatigue and further research is required to improve the current management of this debilitating symptom.

Kinetic measurements of shock wave propagation in a three-dimensional complex (dusty) plasma

"Complex plasmas" consist of electrons, ions, and charged microparticles. The latter are individually observable, allowing kinetic measurements in plasmas. Using a sudden gas pulse, a traveling perturbation was initiated in such a complex plasma and its propagation, acceleration, and steepening-possibly into a shock was followed. The experiment was performed in the PKE-Nefedov laboratory under microgravity conditions on the international space station, i.e., in a complex plasma cloud with very little stored (potential or free) energy and thus free of, e.g., parametric instabilities. The perturbation front remained remarkably smooth, with a microroughness of the order of the interparticle distance. The observations are presented and interpreted.

Quantitative versus morphological assessment of liver fibrosis: semi-quantitative scores are more robust than digital image fibrosis area estimation

BACKGROUND/AIM

Digital image analysis (DIA) allows quantitative assessment of fibrosis on liver biopsy. Accurate determination of a threshold greyscale level representing fibrous tissue is critical. This method has not been fully evaluated in clinical practice.

METHODS

Digital images of stained liver biopsy sections were captured by microscopy and converted to greyscale. A novel method of determining the threshold greyscale value at which to measure fibrosis area was developed (peak proportion area change (PPAC)). Reproducibility was tested in comparison with standard interactive thresholding and with semi-quantitative scoring using the Histological activity index (HAI) system by a histopathologist. Fibrosis areas for different sections from the same biopsy core were also compared by each method.

RESULTS

Comparison between PPAC and interactive thresholding method demonstrated superior reproducibility of the PPAC method: r > 0.7, P < 0.001 compared with r = 0.19-0.64 (not all reaching significance). On a single section, reproducibility was similar for PPAC and the modified HAI system. When different sections from the same core were compared, the HAI system was more robust.

CONCLUSIONS

The PPAC method is superior to standard interactive thresholding. However, variability in DIA scores between sections invalidates the technique for clinical use and semi-quantitative scoring systems remain the gold standard for fibrosis assessment.

Imaging the magnetic spin structure of exchange-coupled thin films

We have investigated the magnetic spin structure of a soft-magnetic film that is exchange-coupled to a hard-magnetic layer to form an exchange-spring layer system. The depth dependence of the magnetization direction was determined by nuclear resonant scattering of synchrotron radiation from ultrathin 57Fe probe layers. In an external field a magnetic spiral structure forms that can be described within a one-dimensional micromagnetical model. The experimental method allows one to image vertical spin structures in stratified media with unprecedented accuracy.

A phase II trial of ZD0473 in platinum-pretreated ovarian cancer

The primary aim of this phase II trial was to assess the antitumour activity of ZD0473 in ovarian cancer patients who had failed initial platinum-based therapy. Patients (n=94) were classified as either platinum-sensitive (n=35) or platinum-resistant (n=59) depending on whether they had relapsed or progressed within 26 weeks of completing first-line platinum-based chemotherapy. Patients initially received 120 mg/m(2) ZD0473 as a 1-h intravenous (i.v.) infusion on day 1 of a 3-week cycle. If well tolerated, the dose could be escalated to 150 mg/m(2). Few patients (9%) withdrew because of treatment-related adverse events and no clinically significant oto-, nephro- or neurotoxicity was observed. Objective response rates for platinum-resistant and sensitive patients were 8.3 and 32.4%, respectively, and clinical benefit was observed in 76.5% of the sensitive patients. Median time to progression was 57 and 180 days, and median time to death was 242 and 402 days, for resistant and sensitive patients, respectively. In conclusion, ZD0473 has a manageable toxicity profile and encouraging activity in platinum-sensitive ovarian cancer patients.

Results of ZD0473 in platinum-pretreated ovarian cancer: analysis according to platinum free interval

Resistance to platinum-containing regimens can develop in many women with ovarian cancer and may lead to relapse in > 80% of patients. ZD0473 is a new-generation platinum agent that, in preclinical studies, shows evidence of antitumour activity and overcomes platinum-resistance mechanisms. This Phase II trial has evaluated the efficacy and tolerability of ZD0473 in second-line ovarian cancer patients. Patients received ZD0473 120 mg/m2 (1-h iv infusion, day 1 q 3-weeks); the starting dose was increased to 150 mg/m2 after a safety review. We report here on results when patients are divided into four cohorts depending upon whether they were considered platinum-resistant or -sensitive. Patients were placed into one of 3 cohorts if they were platinum resistant (relapsed/progressed < or = 26 weeks after completion of prior platinum-based chemotherapy) or cohort 4 if this period was > 26 weeks (sensitive). Ninety-four patients were recruited to the trial (59 resistant, 35 sensitive; median age 58 [range 27-75] years; 86 with performance status [PS] < or = 1). Forty-nine patients received a starting dose of 120 mg/m2, of which 15 escalated to 150 mg/m2, and 45 received a starting dose of 150 mg/m2. Overall, the median number of treatment cycles received was 3 (range 1-8). Grade 3/4 thrombocytopenia was the most common haematological adverse event occurring in 62% of patients overall. Grade 3/4 lethargy, vomiting and nausea were the most common non-haematological toxicities. No clinically significant oto-, nephro- or neurotoxicity was observed. Overall response rates for all platinum-resistant and -sensitive patients were 8.3% and 32.4%, respectively. Stable disease occurred in 17 resistant and 15 sensitive patients.

Rare variants identified in the HNF- 4 alpha beta-cell-specific promoter and alternative exon 1 lack biological significance in maturity onset diabetes of the young and young onset Type II diabetes

AIMS/HYPOTHESIS

The recently identified alternative promoter (P2) of HNF-4 alpha is the major HNF-4 alpha transcription start site in pancreatic beta cells. The significance of the P2 promoter was shown by the identification of a mutation in the IPF-1 binding site of the alternative promoter which cosegregated with diabetes in a large MODY family. The role of the P2 promoter and the associated alternative exon 1 in both MODY and polygenic Type II (non-insulin-dependent) diabetes mellitus is not known. Linkage to this region in studies of Type II diabetes makes the P2 region a strong candidate for a role in Type II diabetes susceptibility.

METHODS

To assess the role of the P2 region we screened MODY, young-onset Type II diabetic subjects, and probands from Type II diabetes families linked to chromosome 20 for variants of the P2 promoter and associated exon of HNF-4 alpha.

RESULTS

Two variants were found that were not present in the control subjects. The -79 C/T substitution was present in a MODY family but did not perfectly cosegregate with diabetes. A -276 G/T substitution was identified in two UK young-onset diabetes probands but did not co-segregate with diabetes. Reporter gene studies did not indicate changes in transcriptional activity caused by either the -79 C/T or -276 G/T single nucleotide substitutions.

CONCLUSION/INTERPRETATION

We found no evidence to suggest that variation in the P2 proximal promoter region and associated alternative exon 1 of HNF-4 alpha contribute to young onset Type II diabetes susceptibility in Northern Europeans.

Hepatic stem cells

The liver in an adult healthy body maintains a balance between cell gain and cell loss. Though normally proliferatively quiescent, hepatocyte loss such as that caused by partial hepatectomy, uncomplicated by virus infection or inflammation, invokes a rapid regenerative response to restore liver mass. This restoration of moderate cell loss and 'wear and tear' renewal is largely achieved by hepatocyte self-replication. Furthermore, hepatocyte transplants in animals have shown that a certain proportion of hepatocytes can undergo significant clonal expansion, suggesting that hepatocytes themselves are the functional stem cells of the liver. More severe liver injury can activate a potential stem cell compartment located within the intrahepatic biliary tree, giving rise to cords of bipotential so-called oval cells within the lobules that can differentiate into hepatocytes and biliary epithelial cells. A third population of stem cells with hepatic potential resides in the bone marrow; these haematopoietic stem cells can contribute to the albeit low renewal rate of hepatocytes, make a more significant contribution to regeneration, and even completely restore normal function in a murine model of hereditary tyrosinaemia. How these three stem cell populations integrate together to achieve a homeostatic balance is not known. This review focuses on two major aspects of liver stem cell biology: firstly, the identity of the liver stem cells, and secondly, their potential value in the treatment of major liver disease.

Ageing in plants

Ageing in green plants differs in some fundamental ways from the process in animals. The seasonal cycle and persistence of a plant is governed by a combination of the determinate or indeterminate status of meristems (growth centres) and the cell death and disposal strategies employed by plants to generate well-adapted anatomies and morphologies. The degree of perenniality depends on the balance between exploratory growth and the wave of tissue death that succeeds it, and extremes of longevity can arise by relatively minor changes in the quantitative relationship between growth and death. The senescence and elimination of organs and tissues are related to the internal reallocation of resources but are programmed phases in the integrated development of the whole plant and do not represent a kind of ageing by stress or starvation. Meristems of long-lived plants accumulate genetic damage but selection mechanisms exist within the organism to control genetic load, and even to exploit somatic mutations that confer adaptive benefits. It is concluded that most plants do not age in the strict gerontological sense and that extremely long-lived forms like trees and clonal creeping perennials are sustained by selection and correction at the level of semi-autonomous cell lineages.

What stay-green mutants tell us about nitrogen remobilization in leaf senescence

Leaf senescence has an important role in the plant's nitrogen economy. Chlorophyll catabolism is a visible symptom of protein mobilization. Genetic and environmental factors that interfere with yellowing tend to modify protein degradation as well. The chlorophyll-protein relationship is much closer for membrane proteins than it is for soluble or total leaf proteins. In stay-greens, genotypes with a specific defect in the chlorophyll catabolism pathway, soluble protein degradation during senescence may be close to normal, but light-harvesting and reaction centre thylakoid membrane proteins are much more stable. Genes for the chlorophyll catabolism pathway and its control are important in the regulation of protein mobilization. Genes for three steps in the pathway are reported to have been isolated. The gene responsible for the stay-green phenotype in grasses and legumes has not yet been cloned but a fair amount is known about it. Pigment metabolism in senescing leaves of the Festuca-Lolium stay-green mutant is clearly disturbed and is consistent with a blockage at the ring-opening (PaO) step in chlorophyll breakdown. PaO is de novo synthesized in senescence and thought to be the key enzyme in the chlorophyll a catabolic pathway. The stay-green mutation is likely to be located in the PaO gene, or a specific regulator of it. These genes may well be in the various senescence-enhanced cDNA collections that have been generated, but functional handles on them are currently lacking. When the stay-green locus from Festuca pratensis was introgressed into Lolium temulentum, a gene encoding F. pratensis UDPG-pyrophosphorylase was shown to have been transferred on the same chromosome segment. A strategy is described for cloning the stay-green gene, based on subtractive PCR-based analyses of intergeneric introgressions and map-based cloning.

Effects of a stay-green mutation on plant nitrogen relations in Lolium perenne during N starvation and after defoliation

The stay-green mutation of the nuclear gene sid results in inhibition of chlorophyll degradation during leaf senescence in grasses, reducing N remobilization from senescing leaves. Effects on growth of Lolium perenne L. were investigated during N starvation (over 18 d) and after severe defoliation, when leaf growth depends on the remobilization of internal N. Rates of dry mater production, partitioning between shoots and roots, and re-partitioning of N from shoots to roots were very similar in stay-green and normal plants under N starvation. Km and Vmax for net uptake of NH4+ were also similar for both genotypes, and Vmax increased with the duration of N deprivation. The mutation had little effect on recovery of leaf growth following severe defoliation, but stay-green plants recommenced NO3- and K+ uptake 1 d later than normal plants. Import of remobilized N into new leaves was generally similar in both lines. However, stay-green plants remobilized less N from stubble compared with normal plants. It was concluded that the sid locus stay-green mutation has no significant adverse effect on the growth of L perenne during N starvation, or recovery from severe defoliation when plants are grown under an optimal regime of NO3- supply both before and after defoliation. The absence of any effect on leaf dry matter production implies that the difference in foliar N availability attributable to this mutation has little bearing on productivity, at least in the short to medium term.

Efficient Deprotection of Phenol Methoxymethyl Ethers Using a Solid Acid Catalyst with Wells-Dawson Structure

Deprotection of various phenols from their respective methoxymethyl ethers using an heteropolyacid catalyst was studied. The catalyst was the Wells-Dawson heteropolyacid, used both in bulk or supported on silica. Yields were high to quantitative after less than one hour reaction time and the catalyst was easily recoverable and reusable.

A distant upstream promoter of the HNF-4alpha gene connects the transcription factors involved in maturity-onset diabetes of the young

Maturity-onset diabetes of the young (MODY) is a monogenic, autosomal dominant subtype of early-onset diabetes mellitus due to defective insulin secretion by the pancreatic beta-cell in humans. Five different genes have been identified including those encoding the tissue-specific transcription factors expressed in pancreatic beta-cells, i.e. HNF-4alpha (MODY1), HNF-1alpha (MODY3), IPF-1 (also known as PDX-1, MODY4) and HNF-1beta (MODY5). Analyzing the transcription of the HNF-4alpha gene, we now identify an alternative promoter, P2, which is 46 kb 5' to the previously identified P1 promoter of the human gene. Based on RT-PCR this distant upstream P2 promoter represents the major transcription site in pancreatic beta-cells, but is also used in hepatic cells. Transfection assays with various deletions and mutants of the P2 promoter reveal functional binding sites for HNF-1alpha, HNF-1beta and IPF-1, the other transcription factors known to encode MODY genes. We demonstrate the significance of this alternative promoter in a large MODY family where a mutated IPF-1 binding site in the P2 promoter of the HNF-4alpha gene co-segregates with diabetes (LOD score 3.25). These data suggest a regulatory network of the four MODY transcription factors interconnected at the distant upstream P2 promoter of the HNF-4alpha gene.

Internet-assisted exercises in structural analysis

In this report we describe our experience in the analytical chemistry curriculum of teaching spectrometer principles and preparing spectroscopy laboratory exercises by means of virtual instruments. The benefits of the intensified preparation of laboratory exercises by virtual instruments will be evaluated with respect to the subsequent handling of real instruments. The utilization of in-house electronic media with Internet resources for elucidation and verification of a structural assignment will also be considered.

Characterization of novel HLA-DR11-restricted HCV epitopes reveals both qualitative and quantitative differences in HCV-specific CD4+ T cell responses in chronically infected and non-viremic patients

The CD4+ T cell response is of critical importance in determining the fate of many viral infections. Clearance of HCV has a strong association with the MHC class II antigen HLA-DR11 suggesting a key role for CD4+ T cells. We used an epitope-prediction program to identify multiple novel HLA-DR11-restricted epitopes derived from several HCV proteins. These epitopes then allowed us to explore the qualitative and quantitative aspects of specific CD4+ T cell responses in HLA-DR11+ patients. Irrespective of the time since viral clearance, all the non-viremic patients recognized four epitopes with a high frequency of IFN-gamma-producing memory CD4+ T cells. There appeared to be two subpopulations of memory cells, immediate "effector" memory cells (Th1 phenotype) and resting "central" memory cells (Th1/0). Chronically infected patients revealed an almost complete absence of HCV epitope-specific IFN-gamma-producing T cells. However, three of these epitopes induced IL-10 production (down-regulatory) raising the question as to whether these cells play a role in viral persistence. The frequency and phenotype of memory cells is likely to reflect the magnitude of the initial immune response, and suggests that a high frequency of IFN-gamma-secreting CD4+ T cells to multiple epitopes are important in clearance of HCV.

Serotonergic lesion of median raphe nucleus alters nerve growth factor content and vulnerability of cholinergic septohippocampal neurons in rat

About 45% of the serotonergic raphe neurons are reported to express nerve growth factor (NGF) receptors. We therefore investigated whether selective serotonergic lesions of the median or dorsal raphe nuclei are associated with changes in NGF protein levels of the brain and whether the loss of serotonergic function alters the vulnerability of cholinergic septohippocampal neurons. In adult rats the hippocampal NGF content changed in a biphasic way after lesion of the median raphe nucleus by 5,7-dihydroxytryptamine (5,7-DHT), with a significant increase after 2-3 weeks of up to 35%, followed by a significant reduction of 22% below control levels after 7 weeks, and a return to control levels within the following 4 weeks. By contrast, the decrease in hippocampal serotonin and 5-hydroxyindoleacetic acid remained throughout the observation period of 11 weeks, being still reduced to 15 and 30% of the control levels, respectively. In the frontal cortex the partial loss of the serotonergic innervation projecting from the median raphe was associated 5 weeks after 5,7-DHT injection with an increase in NGF protein of 39.7+/-9.6% (P<0.05), which remained elevated up to 11 weeks. At 9 weeks after 5,7-DHT, the lesion of the septohippocampal cholinergic neurons induced by the cholinotoxin ethylcholine aziridinium (AF64A) was exaggerated (P<0.05) as compared to AF64A-treated rats with intact serotonergic innervation. The present data indicate that a serotonergic lesion of the median raphe nucleus results in biphasic changes of NGF protein content and in a delayed increase in the vulnerability of septohippocampal cholinergic neurons.

Characterization of novel HLA-DR11-restricted HCV epitopes reveals both qualitative and quantitative differences in HCV-specific CD4+ T cell responses in chronically infected and non-viremic patients

The CD4+ T cell response is of critical importance in determining the fate of many viral infections. Clearance of HCV has a strong association with the MHC class II antigen HLA-DR11 suggesting a key role for CD4+ T cells. We used an epitope-prediction program to identify multiple novel HLA-DR11-restricted epitopes derived from several HCV proteins. These epitopes then allowed us to explore the qualitative and quantitative aspects of specific CD4+ T cell responses in HLA-DR11+ patients. Irrespective of the time since viral clearance, all the non-viremic patients recognized four epitopes with a high frequency of IFN-gamma-producing memory CD4+ T cells. There appeared to be two subpopulations of memory cells, immediate "effector" memory cells (Th1 phenotype) and resting "central" memory cells (Th1/0). Chronically infected patients revealed an almost complete absence of HCV epitope-specific IFN-gamma-producing T cells. However, three of these epitopes induced IL-10 production (down-regulatory) raising the question as to whether these cells play a role in viral persistence. The frequency and phenotype of memory cells is likely to reflect the magnitude of the initial immune response, and suggests that a high frequency of IFN-gamma-secreting CD4+ T cells to multiple epitopes are important in clearance of HCV.

Ovarian cancer chemotherapy

The treatment of ovarian cancer has evolved over the past two decades from one of palliation to one where patients can achieve prolonged remission and cure. Although prognosis remains poor, it has improved with the intervention of a multidisciplinary team and greater site specialization in the organization of cancer services. The introduction of new chemotherapy agents both as first line treatment and on relapse has had a benefit in terms of overall survival and progression-free survival. In this review we describe first-line therapy, including the use of intraperitoneal chemotherapy, the importance of dose and dose intensity in platinum agents and the treatment of refractory and relapsed disease. Finally the review focuses on important prognostic factors and how these can be used to predict outcome.

Androgenesis from Festuca pratensis x Lolium multiflorum amphidiploid cultivars in order to select and stabilize rare gene combinations for grass breeding

Androgenesis using amphidiploid cultivars of Festuca pratensis x Lolium multiflorum as parents, overcame earlier problems that gave rise to widespread plant sterility amongst androgenic Festulolium populations. Two Festuca pratensis x Lolium multiflorum (2n = 4x = 28) cultivars, Sulino and Felopa, were highly amenable to androgenesis and 10% of plants, including some novel androgenic genotypes, had sufficient fertility to produce progeny and further generations. The genomes of amphidiploid cultivars, which represent the F8 generation, were the result of considerable intergeneric chromosome recombination. Moreover, during cultivar development, natural and breeders' selection pressures had led to the assembly of gene combinations that conferred good growth characters and fertility with the removal of putative deleterious gene combinations. Over 80% of the androgenic plants derived from the amphidiploid F. pratensis x L. multiflorum (2n = 4x = 28) had 14 chromosomes and were likely to be dihaploids with a single genome of Lolium and of Festuca. In contrast, hybrids of F. pratensis x L. multiflorum (2n = 2x = 14) found naturally are invariably sterile. Structural reorganization within the genomes of the androgenic Festulolium plants had restored fertility in genotypes expected to contain the haploid genome of Lolium and Festuca. This provided opportunities for their future incorporation in breeding programmes and the development of fertile diploid Lolium-Festuca hybrids. Amongst the androgenic plants, Festulolium genotypes were recovered that conferred excellent drought resistance or freezing tolerance and were thought to be highly suitable for entry into plant breeding programmes.

The enigmatic new Indochinese bovid, Pseudonovibos spiralis: an extraordinary forgery

In 1993, the discovery of several pairs of lyre-shaped horns with corrugations was recorded in Vietnam and regarded as evidence for a new, large bovid, later referred to as Pseudonovibos spiralis Peter & Feiler, 1994. Despite numerous field investigations made since 1994 in Vietnam and Cambodia, no new anatomical evidence has ever been found, except for two frontlets with their horn cores and horn sheaths. A new investigation has been carried out on six frontlets and based on a histological analysis of the keratin. It shows that the horns of P. spiralis are merely a skillful forgery made by carving and distorting ordinary cow horns. The horns of Pseudonovibos spiralis were, in some cases, positioned back onto the corresponding horn cores of domestic cow frontlets. The name Pseudonovibos spiralis is thus a junior synonym of Bos taurus, yet it remains valid and available.

Evidence from DNA that the mysterious 'linh duong' (Pseudonovibos spiralis) is not a new bovid

In 1993, several horns of an unknown mammal were collected in the south of Vietnam. Due to the unusual characteristics of its horns, the 'linh duong', as named by Vietnamese hunters, was quickly described as belonging to a new monospecific genus of bovid, i.e. Pseudonovibos spiralis Peter & Feiler, 1994. The taxonomic status of Pseudonovibos was a highly controversial subject, and it has been suggested that this enigmatic species may be related to three different groups of Bovidae: Antilopini (gazelles), Bovini (cattle, bisons, buffaloes), and Caprini sensu lato (goats, sheep and allies). To assess the phylogenetic relationships of the linh duong within the family Bovidae, two different DNA markers, the nuclear lactoferrin and the mitochondrial cytochrome b genes, were sequenced from bone samples of four trophies collected during 1925 in Indochina. Results show that the mysterious horns of linh duong belong to domestic cattle (Bos taurus). Thus, the linh duong is not a new mammal and the scientific name Pseudonovibos spiralis should be abandoned.

Controversial attachments: the indirect treatment of fostered and adopted children via Parent Co-Therapy

Fostered and adopted children often show a large array of psychosocial problems and are conceptualized as having attachment disorders. It can be necessary to engage such children in direct mental health treatment, in addition to interventions set up to deal with their problems through agencies such as Education and Social Services. In order to protect children from a multitude of treating professionals, thereby potentially further weakening the emerging parental attachments, a model is proposed of indirect treatment of children, with the adoptive parents as co-therapists. This elevates the status of parents and is controversial in child mental health work as it challenges traditional hierarchies. We refer to this model, based on a single case study, as Parent Co-Therapy (PCT). It is proposed that this may be a suitable treatment model for fostered and adopted children, particularly in the early years of placement. The model has the potential to strengthen the children's attachments to the parents and vice versa, with a concomitant reduction in symptomatology.

Prospective validation of renal function-based carboplatin dosing in children with cancer: A United Kingdom Children's Cancer Study Group Trial

PURPOSE

Carboplatin dosing in adults with cancer is based on renal function. The purpose of the current study was to validate a previously developed pediatric carboplatin-dosing formula.

PATIENTS AND METHODS

Thirty-eight pediatric patients were randomized to receive a carboplatin dose calculated according to surface area or a renal function-based dosing formula. On the next course of therapy, the alternative dosing method was used for each patient. Carboplatin pharmacokinetics (based on free plasma platinum concentrations) were measured after both courses.

RESULTS

The mean observed areas under the carboplatin concentration-versus-time curve (AUCs) after renal function- and surface area-based dosing were 98% and 95% of the target AUCs, respectively. The variation in the observed AUC was significantly less after renal function-based dosing (F test, P =.02), such that 74% of courses had an observed AUC within +/- 20% of the target value, versus 49% for courses after dosing according to surface area. Only one of 22 courses at the center with the most experience with renal function-based dosing was associated with an AUC outside +/- 20% of the target value, versus nine of 22 courses after surface area-based dosing in the same center. There was a relationship (r(2) =.71) between carboplatin AUC and thrombocytopenia in 10 neuroblastoma patients treated with a combination of carboplatin, vincristine, etoposide, and cyclophosphamide.

CONCLUSION

Renal function-based carboplatin dosing in children results in more consistent drug exposure than surface area-based drug administration.

A direct, highly sensitive fluorometric assay for a microsomal cytochrome P450-mediated O-demethylation using a novel coumarin analog as substrate

A highly sensitive fluorometric assay for the determination of monooxygenase activity in liver microsomes is described. The assay is based on the use of 3-chloro-7-methoxy-4-methylcoumarin which is demethylated to 3-chloro-7-hydroxy-4-methylcoumarin. The rate of formation of 3-chloro-7-hydroxy-4-methylcoumarin was recorded as an increase of fluorescence (lambdaA = 380 nm, lambdaF = 480 nm) with time. When 3-chloro-7-methoxy-4-methylcoumarin was incubated in the presence of MgCl2 and NADPH with rat liver microsomes, a continuous increase of the fluorescence could be measured. The reaction proceeded linearly for about 10 min and at least up to a concentration of 0.1 mg/ml of microsomal protein. Besides 3-chloro-7-hydroxy-4-methylcoumarin a hydroxylated derivative of the substrate was formed as a second metabolite during the incubation. Using an excitation wavelength of 380 nm and a fluorescence/emission wavelength of 480 nm, the fluorescence of this substance (lambdaA = 338 nm, lambdaF = 422 nm) amounted only to about 1% of the fluorescence of the main product. The use of 3-chloro-7-methoxy-4-methylcoumarin as substrate enables the fluorometric determination of the O-dealkylation activity of a cytochrome P450-dependent monooxygenase system in rat liver which is inducible by phenobarbital but not by 3-methylcholanthrene.

Annuality, perenniality and cell death

This essay considers annuality and perenniality as quantitative traits and discusses the application of established and new genetic tools to the analysis of plant life histories. Annual/perennial status is a function of meristem determinacy in combination with the processes of cell death and disposal employed by plants to generate well-adapted anatomies and morphologies. Creeping perennials, like clover or bracken, seem to move around in the environment. They do this by extending into unoccupied space while the oldest tissues behind the growing and mature regions senesce, die and decompose. Trees do essentially the same thing, except that they develop vertically and the old dead tissue does not disappear but instead persists as wood. A root system is a kind of upended vertical perennial. The balance between exploratory growth and the wave of tissue death that succeeds it is a major determinant of perenniality. So although perenniality and annuality may appear to be dramatically different traits, extremes of behaviour can arise by a relatively minor change in the relationship between growth and death. This conclusion is supported by evidence from genome dosage studies, from the practical experiences of breeding perennial-type traits into annual backgrounds and from molecular cladistics. Applications of methods for the genetic analysis of quantitative characters are described, including the exploitation of introgression mapping in Lolium-Festuca and quantitative trait locus mapping in cereals and other species.

A sensitivity analysis on the atmospheric transformation and deposition of mercury in north-eastern USA

This paper presents the results of a sensitivity analysis on the factors that affect dry and wet deposition of atmospheric mercury (Hg), using a regional scale air quality model. Simulations were conducted for the north-eastern USA during a summer week and a winter week in 1997. Simulation results for the summer week and the winter week in general showed similar responses to changes in emission, environmental conditions, and alternative chemical mechanisms. Reduction of the ambient concentrations of soot or ozone was shown to reduce the wet deposition of Hg. When averaged over the summer and the winter week, the total deposition to the simulation domain would be reduced by 26% by reducing Hg emission from anthropogenic sources within the domain by 50%. For individual grids, however, only locations near local sources obtained noticeable reductions in ambient concentration and wet deposition due to the influence of re-emission from the natural surfaces and regional/global scale transport. The reduction in deposition would reach 36% if all Hg(II) emitted from anthropogenic sources were attached to particles. The total deposition was predicted to decrease by 22% when the gas phase Hg(II)-Hg(p) partitioning was included in the model. Only small changes in total deposition were observed by including the gas-phase ozone-Hg(0), reaction and the aqueous phase chlorine-Hg(0), reaction, and by lowering ambient concentrations of Hg(II) and Hg(p) at the upper lateral boundaries. During the summer week, Hg(II) deposition contributed 40% or more to the total deposition. The contribution increased to 70% in the winter week.

Retrotransposon evolution in diverse plant genomes

Retrotransposon or retrotransposon-like sequences have been reported to be conserved components of cereal centromeres. Here we show that the published sequences are derived from a single conventional Ty3-gypsy family or a nonautonomous derivative. Both autonomous and nonautonomous elements are likely to have colonized Poaceae centromeres at the time of a common ancestor but have been maintained since by active retrotransposition. The retrotransposon family is also present at a lower copy number in the Arabidopsis genome, where it shows less pronounced localization. The history of the family in the two types of genome provides an interesting contrast between "boom and bust" and persistent evolutionary patterns.

Characterisation of a cysteine protease cDNA from Lolium multiflorum leaves and its expression during senescence and cytokinin treatment

A cysteine protease cDNA clone (See1) highly homologous to barley aleurain was isolated from Lolium multiflorum leaves. During leaf senescence, expression of the See1 mRNA and protein was strongly enhanced. In dark-incubated leaf segments, cytokinin delayed senescence and reduced expression of both See1 mRNA and protein.

Acute myocardial infarction occurring in versus out of the hospital: patient characteristics and clinical outcome. Maximal Individual TheRapy in Acute Myocardial Infarction (MITRA) Study Group

OBJECTIVES

We describe the baseline characteristics and clinical course of patients who had an acute myocardial infarction (AMI) during their hospital stay.

BACKGROUND

In comparison with patients who had an AMI outside of the hospital (prehospital AMI), the data on patients who had an AMI in the hospital are poorly described.

METHODS

Patients with an in-hospital AMI were prospectively registered in the Southwest German Maximal Individual TheRapy in Acute myocardial infarction (MITRA) study and compared with patients with prehospital AMI.

RESULTS

Of 5,888 patients with AMI, 403 patients (6.8%) had an in-hospital AMI. These patients were older, more often male and sicker as compared with the patients with a prehospital AMI. They also showed a higher prevalence of concomitant diseases, such as arterial hypertension, diabetes mellitus, renal insufficiency and contraindications for thrombolysis. There was no significant difference regarding the use of reperfusion therapy, either thrombolysis (in-hospital AMI 44.2% vs. prehospital AMI 49.1%; odds ratio [OR] 0.86, 95% confidence interval [CI] 0.70 to 1.05) or primary angioplasty (9.9% vs. 8.2%; OR 1.23, 95% CI 0.88 to 1.73), or a combination of both, between the two groups. The interval from symptom onset to the start of treatment in patients receiving reperfusion therapy was 55 min for patients with an in-hospital AMI versus 180 min for patients with a prehospital AMI (p = 0.001). In-hospital death occurred in 110 (27.3%) of 403 patients with an in-hospital versus 762 (13.9%) of 5,485 patients with a prehospital AMI (OR 2.33, 95% CI 1.85 to 2.94). This was confirmed by logistic regression analysis after adjusting for other confounding variables (OR 1.67, 95% CI 1.23 to 2.24).

CONCLUSIONS

In-hospital AMI occurred in 6.8% of patients. Time to intervention was shorter; however, the use of reperfusion therapy for in-hospital AMI was not different from that for prehospital AMI. In particular, primary angioplasty seems to be underused in these patients. This, as well as the selection of patients, may result in the high hospital mortality rate of 27.3%.

Sequence of the two operons encoding the four core subunits of the cytochrome b(6)f complex from the thermophilic Cyanobacterium synechococcus elongatus

The genes encoding cytochrome f (petA), cytochrome b(6) (petB), the Rieske FeS-protein (petC), and subunit IV (petD) of the cytochrome b(6)f complex from the thermophilic cyanobacterium Synechococcus elongatus were cloned and sequenced. Similar to other cyanobacteria, the structural genes are arranged in two short, single-copy operons, petC/petA and petB/petD, respectively. In addition, five open reading frames with homology to known orfs from the cyanobacterium Synechocystis PCC 6803 were identified in the immediate vicinity of these two operons.

Inhibition of extracellular signal-regulated kinase enhances Ischemia/Reoxygenation-induced apoptosis in cultured cardiac myocytes and exaggerates reperfusion injury in isolated perfused heart

Three major mammalian mitogen-activated protein kinases, extracellular signal-regulated kinase (ERK), p38, and c-Jun NH(2)-terminal protein kinase (JNK), have been identified in the cardiomyocyte, but their respective roles in the heart are not well understood. The present study explored their functions and cross talk in ischemia/reoxygenation (I/R)-induced cardiac apoptosis. Exposing rat neonatal cardiomyocytes to ischemia resulted in a rapid and transient activation of ERK, p38, and JNK. On reoxygenation, further activation of all 3 mitogen-activated protein kinases was noted; peak activities increased (fold) by 5.5, 5.2, and 6.2, respectively. Visual inspection of myocytes exposed to I/R identified 18.6% of the cells as showing morphological features of apoptosis, which was further confirmed by DNA ladder and terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL). Myocytes treated with PD98059, a MAPK/ERK kinase (MEK1/MEK2) inhibitor, displayed a suppression of I/R-induced ERK activation, whereas p38 and JNK activities were increased by 70.3% and 55.0%, respectively. In addition, the number of apoptotic cells was increased to 33.4%. With pretreatment of cells with SB242719, a selective p38 inhibitor, or SB203580, a p38 and JNK2 inhibitor, I/R+PD98059-induced apoptotic cells were reduced by 42.8% and 63.3%, respectively. Hearts isolated from rats treated with PD98059 and subjected to global ischemia (30 minutes)/reoxygenation (1 hour) showed a diminished functional recovery compared with the vehicle group. Coadministration of SB203580 attenuated the detrimental effects of PD98059 and significantly improved cardiac functional recovery. The data taken together suggest that ERK plays a protective role, whereas p38 and JNK mediate apoptosis in cardiomyocytes subjected to I/R, and the dynamic balance of their activities is critical in determining cardiomyocyte fate subsequent to reperfusional injury.

Rapid access to infrared reference spectra of arbitrary organic compounds: scope and limitations of an approach to the simulation of infrared spectra by neural networks

Substance identification by infrared spectroscopy is performed by comparison of the experimental spectrum with a reference spectrum from a printed compilation or a database. If the analyzed compound can not be found in a database the corresponding reference spectrum has to be simulated. In order to achieve this, several reasonable candidates of structures for the compound at hand have to be conceived and for all these, infrared spectra have to be developed. The simulated spectrum that is most similar to the experimental suggests the correct structure. A rapid spectrum prediction method based on neural networks has been developed that supplies reference spectra for any organic compound. The scope and limitations of this method will be discussed on a test set of 16 compounds representing a broad range of organic chemistry.

De novo evolution of satellite DNA on the rye B chromosome

The most distinctive region of the rye B chromosome is a subtelomeric domain that contains an exceptional concentration of B-chromosome-specific sequences. At metaphase this domain appears to be the physical counterpart of the subtelomeric heterochromatic regions present on standard rye chromosomes, but its conformation at interphase is less condensed. In this report we show that the two sequence families that have been previously found to make up the bulk of the domain have been assembled from fragments of a variety of sequence elements, giving rise to their ostensibly foreign origin. A single mechanism, probably based on synthesis-dependent strand annealing (SDSA), is responsible for their assembly. We provide evidence for sequential evolution of one family on the B chromosome itself. The extent of these rearrangements and the complexity of the higher-order organization of the B-chromosome-specific families indicate that instability is a property of the domain itself, rather than of any single sequence. Indirect evidence suggests that particular fragments may have been selected to confer different properties on the domain and that rearrangements are frequently selected for their effect on DNA structure. The current organization appears to represent a transient stage in the evolution of a conventional heterochromatic region from complex sequences.

Chlorophyll breakdown in Chlorella protothecoides: characterization of degreening and cloning of degreening-related genes

Chlorella protothecoides cultures grown in a nitrogen-free bleaching medium (BM-N) in the dark rapidly degraded chlorophyll (Chl) to red catabolites. This degreening process was investigated under different growth conditions. Supply of nitrogen to the culture medium (BM+N) inhibited bleaching and the synthesis of catabolites as did the addition to BM-N of cycloheximide or a chelator, 2,2'-bipyridyl. In contrast, chloramphenicol or the protease inhibitor E64 had no effect. During bleaching, Chl breakdown was accompanied by the degradation of cellular proteins such as light-harvesting complex II, cytochrome f and protochlorophyllide oxido-reductase. During growth in BM-N, protease activity increased and proteins immunologically detectable with an antibody against a senescence-enhanced cysteine protease accumulated. cDNAs from BM-N and BM+N cells were used for differential and subtractive screening to isolate cDNAs representing genes with degreening-enhanced expression (dee) in C. protothecoides. Several different dees were identified with different patterns of expression during Chlorella growth but which were all expressed at higher levels during bleaching. Among these, dee4 was most abundant and its expression was exclusive in BM-N cultures. Analysis of the dee sequences showed that they encode different proteins including a novel amino acid carrier (dee4), ferritin, ATP-dependent citrate lyase, a Ca2+-binding protein, MO25, ubiquinone-cytochrome c-reductase and several new proteins.

Five ways to stay green

The relationship between carbon income and expenditure over the life of a leaf is described and related to the productivity benefits of altering the timing of senescence initiation. In genetic variants with delayed leaf senescence ('stay-greens') deconstruction of the photosynthetic apparatus during leaf senescence is partially or completely prevented. Although the staygreen phenotype is superficially similar in all species and genotypes, the genetic and physiological routes to the trait are diverse. In one type of stay-green, chlorophyll catabolism is disabled. Legumes and monocots with pigment breakdown lesions are discussed. Sorghum is presented as an example of another kind of stay-green in which perennial tendencies have been bred into a monocarpic annual crop species. Transgenic approaches are briefly discussed (enhanced endogenous cytokinins, reduced ethylene production or perception). An alternative route towards making a stay-green phenotype is through quantitative trait mapping and marker-assisted selection. Loci for greenness in pearl millet have been identified, some of which are associated with drought responses or flowering time. Finally the question of the limits on stay-green as a productivity-enhancing character is addressed.

Naturally occurring mutations in the human HNF4alpha gene impair the function of the transcription factor to a varying degree

The hepatocyte nuclear factor (HNF)4alpha, a member of the nuclear receptor superfamily, regulates genes that play a critical role in embryogenesis and metabolism. Recent studies have shown that mutations in the human HNF4alpha gene cause a rare form of type 2 diabetes, maturity onset diabetes of the young (MODY1). To investigate the properties of these naturally occurring HNF4alpha mutations we analysed five MODY1 mutations (R154X, R127W, V255M, Q268X and E276Q) and one other mutation (D69A), which we found in HepG2 hepatoma cells. Activation of reporter genes in transfection assays and DNA binding studies showed that the MODY1-associated mutations result in a variable reduction in function, whereas the D69A mutation showed an increased activity on some promoters. None of the MODY mutants acted in a dominant negative manner, thus excluding inactivation of the wild-type factor as a critical event in MODY development. A MODY3-associated mutation in the HNF1alpha gene, a well-known target gene of HNF4alpha, results in a dramatic loss of the HNF4 binding site in the promoter, indicating that mutations in the HNF4alpha gene might cause MODY through impaired HNF1alpha gene function. Based on these data we propose a two-hit model for MODY development.

Transgenic overexpression of human Bcl-2 in islet beta cells inhibits apoptosis but does not prevent autoimmune destruction

Insulin-dependent diabetes mellitus results when > 90% of the insulin-producing beta cells in the pancreatic islets are killed as a result of autoimmune attack by T cells. During the progression to diabetes, islet beta cells die as a result of different insults from the immune system. Agents such as perforin and granzymes, CD95 ligand and tumor necrosis factor-alpha, or cytokines and free-radicals have all been shown to cause beta cell apoptosis. The anti-apoptotic protein, Bcl-2, might protect against some of these stimuli. We have therefore generated transgenic mice expressing human Bcl-2 in their islet beta cells. Although Bcl-2 was able to prevent apoptosis induced by cytotoxic agents against beta cells in vitro, Bcl-2 alone could not prevent or ameliorate cytotoxic or autoimmune beta cell damage in vivo.

Inferring children's categorizations from sequential touching behaviors: an analytical model

A child is assumed to belong to 1 of 2 classes: categorizer or noncategorizer. To determine which, 4 toy animals and 4 toy vehicles were randomly arrayed for touching for 2 min. The task was to infer whether the child was a categorizer or a noncategorizer for vehicles and similarly for animals. A model is proposed that assumes a child's sequence of touches follows one probability distribution if the child is a categorizer and another distribution if the child is a noncategorizer. The proportion of children in each category and the probability of a child being a categorizer for, say, vehicles are among the quantities that can be estimated. Data from 18-month-old children are illustrative. The model appears efficient and robust.

Lesion of the median raphe nucleus: a combined behavioral and microdialysis study in rats

The purpose of the present study was to investigate the behavioral consequences and the neurochemical correlates of a 5,7-dihydroxytryptamine (5,7-DHT) lesion of the median raphe nucleus (MRN) in rats. Anxiety-related behavior was assessed in the elevated plus maze test on days 5, 14, and 21 after lesioning. In general, behavior of MRN-lesioned rats was unchanged when compared with sham-lesioned or untreated controls. Neurochemically, microinjection of 5,7-DHT into the MRN resulted in 87.5% depletion of hippocampal 5-HT content. Using the in vivo microdialysis technique, the exposure of 5,7-DHT-lesioned rats to the elevated plus-maze failed to increase extracellular 5-HT release (94%) in the hippocampus, as shown in sham-lesioned (150%) or untreated controls (194%). Moreover, application of fenfluramine (10 mg/kg, i.p.) evoked a 10-fold increase in hippocampal extracellular 5-HT levels in sham-lesioned animals, whereas in 5,7-DHT lesioned rats 5-HT was only slightly increased. The results demonstrate, that a marked reduction of 5-HT release from the MRN is not necessarily accompanied by anxiolytic-like behavior.