Beta-carotene supplementation: a good thing, a bad thing, or nothing?

Available data from several completed large-scale randomized trials indicate that beta-carotene supplementation for durations up to 12 years has no overall benefit in well-nourished populations on the incidence of cardiovascular disease or the middle-to-late stages of carcinogenesis. Several important questions, however, remain unanswered. The post-trial follow-up of completed trials, together with the results of several ongoing trials of beta-carotene supplementation, will contribute reliable information to the totality of evidence from basic research, animal studies, observational epidemiologic studies, and completed trials, thus allowing more rational clinical decisions for individual patients and policy decisions for the health of the general public.     

Mammalian polyamine catabolism: a therapeutic target, a pathological problem, or both?

With the recent discovery of the polyamine catabolic enzyme spermine oxidase (SMO/PAOh1), the apparent complexity of the polyamine metabolic pathway has increased considerably. Alone or in combination with the two other known members of human polyamine catabolism, spermidine/spermine N(1)-acetyltransferase, and N(1)-acetylpolyamine oxidase (PAO), SMO/PAOh1 expression has the potential to alter polyamine homeostasis in response to normal cellular signals, drug treatment and environmental and/or cellular stressors. The activity of the oxidases producing toxic aldehydes and the reactive oxygen species (ROS) H(2)O(2), suggest a mechanism by which these oxidases can be exploited as an antineoplastic drug target. However, inappropriate activation of the pathways may also lead to pathological outcomes, including DNA damage that can lead to cellular transformation. The most recent data suggest that the two polyamine catabolic pathways exhibit distinct properties and understanding these properties should aid in their exploitation for therapeutic and/or chemopreventive strategies.     

Malaria vaccines: into a mirror, darkly?

Recent advances in adjuvant and delivery systems, in addition to a wealth of genomic and proteomic information on parasite composition, are being harnessed to develop a malaria vaccine. To do so effectively, it might be necessary to reassess the criteria by which formulations have been selected to progress to clinical trials. Specifically, better in vitro surrogates of protective immunity, better animal models and a more complete understanding of the unique canvas presented by the immune system of individuals who have experienced multiple malaria infections are needed.     

P430: a retrospective, 1971–2001

The spectral species P430 and its spectral and kinetic properties are briefly reviewed. Currently available evidence shows P430 to be the optic-spectral representation of FeS-A/B, the electron acceptor(s) of Photosystem I (PS I). Retired (formerly with the Charles F. Kettering Research Laboratory, Yellow Springs, Ohio, USA). This revised version was published online in June 2006 with corrections to the Cover Date.     

Vertebrate left and right: Finally a cascade,but first a flow?

Vertebrate development gives rise to systematic, normally reliably coordinated left-right asymmetries of body structure. This “handed asymmetry” of anatomy must take its ultimate origin from some chiral molecular assembly (one exhibiting no planes of symmetry and thus, having an intrinsic “handedness”) within the early embryo's cells. But which molecules are involved, how is their chiral property coordinately aligned among many cells, and how does it “seed” the differential cascades of gene expression that characterise right and left halves of the embryo? Recent molecular characterisations of mouse mutations that randomise or reverse body asymmetries have offered tantalising clues to the chiral initiator molecules, but the findings in a subsequent Cell paper (Nonaka S, Yosuke T, Okada Y, Takeda S, Harada K, Kanai Y, Kido M, Hirokawa N. Randomisation of left-right asymmetry due to loss of nodal cilia generating a leftward flow of extraembryonic fluid in mice lacking KIF3B motor protein. Cell 1998;95:829–837. [Reference 1]) may help us understand how the first gene expression asymmetries occur. BioEssays 21:537–541, 1999. © 1999 John Wiley & Sons, Inc.     

Visceral pain: gut microbiota,a new hope?

Background

Visceral pain is a complex and heterogeneous disorder, which can range from the mild discomfort of indigestion to the agonizing pain of renal colic. Regulation of visceral pain involves the spinal cord as well as higher order brain structures. Recent findings have linked the microbiota to gastrointestinal disorders characterized by abdominal pain suggesting the ability of microbes to modulate visceral hypersensitivity and nociception to pain.

Main body

In this review we describe the neuroanatomical basis of visceral pain signaling and the existing evidence of its manipulation exerted by the gut microbiota. We included an updated overview of the potential therapeutic effects of dietary intervention, specifically probiotics and prebiotics, in alleviating hypersensitivity to visceral pain stimuli.

Conclusions

The gut microbiota dramatically impacts normal visceral pain sensation and affects the mechanisms mediating visceral nociception. Furthermore, manipulation of the gut microbiota using prebiotics and probiotics plays a potential role in the regulation of visceral pain disorders.

     

The euryarchaeotes, a subdomain of Archaea, survive on a single DNA polymerase: fact or farce?

Archaea is now recognized as the third domain of life. Since their discovery, much effort has been directed towards understanding the molecular biology and biochemistry of Archaea. The objective is to comprehend the complete structure and the depth of the phylogenetic tree of life. DNA replication is one of the most important events in living organisms and DNA polymerase is the key enzyme in the molecular machinery which drives the process. All archaeal DNA polymerases were thought to belong to family B. This was because all of the products of pol genes that had been cloned showed amino acid sequence similarities to those of this family, which includes three eukaryal DNA replicases and Escherichia coli DNA polymerase II. Recently, we found a new heterodimeric DNA polymerase from the hyperthermophilic archaeon, Pyrococcus furiosus. The genes coding for the subunits of this DNA polymerase are conserved in the euryarchaeotes whose genomes have been completely sequenced. The biochemical characteristics of the novel DNA polymerase family suggest that its members play an important role in DNA replication within euryarchaeal cells. We review here our current knowledge on DNA polymerases in Archaea with emphasis on the novel DNA polymerase discovered in Euryarchaeota.     

Fever with lymphadenopathy – Kikuchi Fujimoto disease,a great masquerader: a case report

Background

Kikuchi Fujimoto disease is an uncommon benign condition of necrotizing histiocytic lymphadenitis commonly seen in East Asian and Japanese populations. It commonly presents with fever, cervical lymphadenopathy, and elevated inflammatory markers. Diagnosis of Kikuchi Fujimoto disease is based on histopathological studies of the involved lymph nodes. The presentation of Kikuchi Fujimoto disease can mimic many sinister conditions including lymphoma. Treatment is mainly supportive provided that accurate diagnosis is made and sinister conditions like lymphoma ruled out.

Case presentation

We report the case of an 18-year-old Sri Lankan Moor woman who presented with fever and cervical lymphadenopathy for 1 month. She had elevated inflammatory markers with high lactate dehydrogenase and ferritin levels. She had an extensive work-up including an excision biopsy of an involved lymph node and bone marrow biopsy. Finally, a diagnosis of Kikuchi Fujimoto disease was based on histopathology of the lymph node and negative bone marrow biopsy.

Conclusions

Although Kikuchi Fujimoto disease is a self-limiting condition, it is a great masquerader which mimics the clinical features of many sinister conditions including tuberculosis, lymphoma, and adult-onset Still’s disease. Early recognition of the disease is of crucial importance in minimizing potentially harmful and unnecessary evaluations and treatments.

     

Merremiadissecta (Convolvulaceae): Condiment, medicine, ornamental, and weed—a review

Merremia dissecta was first discovered in the Caribbean, then Florida, Mexico, and later in the Old World, where it had been introduced. Historically and currently, the species has been used as a condiment, medicine, and ornamental by an array of cultures. Although the plant has escaped in several areas to become a weed, it continues being sold as an ornament in even those regions. In Argentina, roots ofM. dissecta var. edentata are still used as food by a few indigenous groups. History, uses, and chemistry are discussed regarding these utilizations.

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Merremia dissecta (Convolvulaceas): Un condimento, medicina, ornamental, y maleza— Una revista

Resumen  Merremia dissecta fue primeramente descubierta en el Caribe, luego en la Florida, México y más tarde fue introducida en el Viejo Mundo. Históricamente y aún actualmente se ha usado como condimento, medicina, y ornamentatión por varias culturas. A pesar de que en varias áreas se ha transformado en una mala hierba, se continua vendiendo como un ornamento aún en esas areas. En Argentina, as raices deM. dissecta var. edentata aún son usadas como alimento por unos cuantos grupos indígenas. La historia, los usos y la química de estas utilizaciónes son aquí discutidas.

     

Australian salt lakes: their history,chemistry, and biota — a review

A vast number of large lakes ( 100 km²) are typically very old features of the Australian landscape; they occupy areas which have changed little tectonically (e.g., they occupy ancient drainage systems in Western Australia or lie in deep depressions such as the Great Artesian Basin: Lake Eyre) and have not been transgressed by the sea since at least the Palaeogene. Other salt lakes, most of which are small ( 50 km²), have been affected morphologically during recurring glacial-interglacial cycles (e.g., lakes associated with gypsum or clay lunettes, sabkhas, pans, lakes near the coast behind barrier dunes as a result of sea-level changes) and their sedimentary records represent comparatively much shorter periods of time. There are also a number of unusually young (< 30 000 years) crater lakes, some of which are the best studied lakes in Australia.The major ions encountered today in Australian salt lakes consist of sodium and chloride although some lakes are also calcium sulphate rich. The origin of these ions is briefly discussed. Sodium carbonate lakes are rare in Australia today. Under past climatic/hydrological conditions the chemistry of a number of lakes was apparently different.The biota of Australian salt lakes is mostly endemic; it is highly diversified as witnessed by the crustacean fauna and is well adapted to the harsh conditions prevailing in saline water. This is the result of a long history of aridity in Australia. The characteristics of this biota are presented together with data on its distribution which is primarily related to climatic conditions.