Quantitative study of hepatocytes from minipigs and minipig fetuses exposed to ethanol in vivo

The effect of ethanol on hepatocytes from pregnant minipigs and their half-term fetuses was studied with the aid of morphometric methods. In the pregnant minipigs the hepatocytes of the ethanol-treated animals showed a significant increase in the volume density of mitochondria, autophagic vacuoles, Golgi complexes and smooth endoplasmic reticulum, and a significant decrease of glycogen. In the half-term fetuses the hepatocytes of ethanol-exposed animals showed no significant change in the volume density of mitochondria, peroxisomes, autophagic vacuoles, Golgi complexes, smooth endoplasmic reticulum or glycogen, and no significant change in the surface density of granular endoplasmic cisternae. The present investigation indicates that in the maternal hepatocyte certain cytoplasmic components are quantitatively changed by ethanol, whereas the volume and surface densities of identical components in the fetal hepatocyte are unaffected. The significance of these results is discussed.     

Role of ultrasonography in diagnosing early rheumatoid arthritis and remission of rheumatoid arthritis - a systematic review of the literature

Introduction

Ultrasonography (US) might have an added value to clinical examination in diagnosing early rheumatoid arthritis (RA) and assessing remission of RA. We aimed to clarify the added value of US in RA in these situations performing a systematic review.

Methods

A systematic literature search was performed for RA, US, diagnosis and remission. Methodological quality was assessed; the wide variability in the design of studies prohibited pooling of results.

Results

Six papers on the added value of US diagnosing early RA were found, in which at least bilateral metacarpophalangeal (MCP), wrists and metatarsophalangeal (MTP) joints were scanned. Compared to clinical examination, US was superior with regard to detecting synovitis and predicting progression to persistent arthritis or RA. Eleven papers on assessing remission were identified, in which at least the wrist and the MCP joints of the dominant hand were scanned. Often US detected inflammation in patients clinically in remission, irrespective of the remission criteria used. Power Doppler signs of synovitis predicted X-ray progression and future flare in patients clinically in remission.

Conclusions

US appears to have added value to clinical examination for diagnosing of RA when scanning at least MCP, wrist and MTP joints, and, when evaluating remission of RA, scanning at least wrist and MCP joints of the dominant hand. For both purposes primarily power Doppler US might be used since its results are less equivocal than those of greyscale US.     

Array-A-Lizer: A serial DNA microarray quality analyzer

Background  

The proliferate nature of DNA microarray results have made it necessary to implement a uniform and quick quality control of experimental results to ensure the consistency of data across multiple experiments prior to actual data analysis.     

BioWareDB: the biomedical software and database search engine

A wealth of bioinformatics tools and databases has been created over the last decade and most are freely available to the general public. However, these valuable resources live a shadow existence compared to experimental results and methods that are widely published in journals and relatively easily found through publication databases such as PubMed. For the general scientist as well as bioinformaticists, these tools can deliver great value to the design and analysis of biological and medical experiments, but there is no inventory presenting an up-to-date and easily searchable index of all these resources. To remedy this, the BioWareDB search engine has been created. BioWareDB is an extensive and current catalog of software and databases of relevance to researchers in the fields of biology and medicine, and presently consists of 2800 validated entries. AVAILABILITY: BioWareDB is freely available over the Internet at http://www.biowaredb.org/     

Advantageous attributes of larval whitefringed weevil, Naupactus leucoloma (Coleoptera: Curculionidae) for bioassaying soil fumigants, and responses to pure and plant-derived isothiocyanates

First instars of the soil-inhabiting whitefringed weevil, Naupactus leucoloma (Boheman), are a particularly good bioassay model for assessing volatile soil fumigants and biofumigants. Eggs are readily obtained and can be stored for long periods with larvae hatched on demand and the first instar is non-feeding, surviving without food or shelter. Longevity varies with temperature, but readily accommodates the period required to conduct bioassays without appreciable mortality of untreated controls. In vitro bioassays of pure methyl isothiocyanate, the active ingredient from metham sodium soil fumigant, and the less volatile 2-phenylethyl isothiocyanate, sensitively detected differences in toxicity and effects of temperature. Bioassay of volatiles emitted from hydrolysed tissue of various isothiocyanate-producing Brassica plants revealed widely varying toxicity effects, indicating that bioassays with N. leucoloma are a sensitive and relevant indicator of the potential of different plants for biofumigation of soil-borne pest organisms.     

A model for environmental sex reversal in fish

A mathematical model is presented which combines genetic XX-female/XY-male sex determination with environmental pressure for phenotypic sex reversal. This may occur when fishes are exposed to endocrine disrupters, specifically masculinization by exposure to androgens and feminization by exposure to estrogens. A generic model is derived for the sex ratio in successive generations and three special cases, with chronic and constant pressure to sex reverse, are discussed in detail. These show that, with extreme environmental pressure to masculinize, the male genotype is at risk of dying out but with less extreme pressure, masculinization will not be detectable since the proportion of phenotypic males becomes one-half. With feminization at any pressure to sex reverse, the male and female genotypes will be maintained in a stable sex ratio in which the proportion of genotypic males exceeds one-half and is close to one-half if YY offspring (eggs) are not viable. In converse, the model is also applicable to the genetic ZZ-male/ZW-female system of sex determination in fish. At present suitable data are not available with which to validate the model, but proposals are made for relevant experimental studies.     

Biofumigation and Enhanced Biodegradation: Opportunity and Challenge in Soilborne Pest and Disease Management

Management of soilborne pests and diseases in cropping systems is often highly challenging—in implementation of acceptable methodologies and in dealing with secondary problems. The phase-out of methyl bromide brings this into particularly sharp focus. There is a need for diversified options and alternatives to fill different roles across the soilborne pest and disease management spectrum, but flexibility is limited, as practicalities demand that they fit into a prophylactic methodology. It is against such a backdrop that expectations and promotion of alternatives must be set. There is also a need to recognize potentially serious problems that may have been masked under historical management regimes, but for which the nature of the system offers little scope to avoid or manage.

Biofumigation is the beneficial use of Brassica green manures that release isothiocyanates chemically similar to methyl isothiocyanate, the active agent from the synthetic fumigant metam sodium, which is used as a substitute for methyl bromide in some systems. A systematic approach to research into biofumigation, specifically aimed at overcoming a long history of empiricism, has seen significant recent advances in both basic and applied knowledge. A key development has been achievement of maximal biofumigation potential through greatly enhanced release of appropriate isothiocyanates into soil. These advances have led to commercial adoption, demonstrating that biofumigation, when applied to appropriate production systems, can have efficacy and offer cost savings. Crucially, these systematically derived research and development findings and their adoption now provide the impetus for self-sustaining further development and market penetration of the concept. Despite this success, biofumigation is not seen as being sufficiently powerful or practical in implementation to be an alternative to methyl bromide on a broad scale and misdirection in that regard could be counterproductive to more appropriately targeted further development.

Enhanced microbial biodegradation is a cryptic phenomenon that can diminish the efficacy of soil-applied pesticides, including isothiocyanates and most other currently available methyl bromide substitutes. Because methyl bromide is not susceptible, the phenomenon has potentially serious implications in intensive production systems switching from methyl bromide to reliance on other compounds that are. It is an intractable problem once induced. Avoidance of its onset is the only feasible management strategy. This has been aided for some particularly vulnerable environments by recent clarification of key risk factors associated with soil type, soil pH, and calcium content.     

Dispersal frequency affects local biomass production by controlling local diversity

Dispersal is a major factor regulating the number of coexisting species, but the relationship between species diversity and ecosystem processes has mainly been analysed for communities closed to dispersal. We experimentally investigated how initial local diversity and dispersal frequency affect local diversity and biomass production in open benthic microalgal metacommunities. Final local species richness and local biomass production were strongly influenced by dispersal frequency but not by initial local diversity. Both final local richness and final local biomass showed a hump-shaped pattern with increasing dispersal frequency, with a maximum at intermediate dispersal frequencies. Consequently, final local biomass increased linearly with increasing final richness. We conclude that the general relationship between richness and ecosystem functioning remains valid in open systems, but the maintenance of ecosystem processes significantly depends on the effects of dispersal on species richness and local interactions.     

Affordable biocomputing for everyone: using the Internet,freeware and open-source software

How to build your own complete working biocomputing platform with nothing more than a desktop computer and an Internet connection.