The satellite RNA of barley yellow dwarf virus-RPV is supported by beet western yellows virus in dicotyledonous protoplasts and plants

The subgroup II luteovirus barley yellow dwarf virus-RPV (BYDV-RPV) acts as a helper virus for a satellite RNA (satRPV RNA). The subgroup II luteovirus beet western yellows virus (BWYV) and the ST9-associated RNA (ST9a RNA), a BWYV-associated RNA that encodes a polymerase similar to those of subgroup I luteoviruses, were assayed for their ability to support replication of satRPV RNA. SatRPV RNA was replicated in tobacco protoplasts in the presence of BWYV RNA or a mixture of BWYV plus the ST9a RNA, but not in the presence of ST9a RNA alone. ST9a RNA stimulated BWYV RNA accumulation which, in turn, increased the accumulation of satRPV RNA. SatRPV RNA was encapsidated in BWYV capsids primarily as circular monomers, which differs from the linear monomers found in BYDV (RPV + PAV) particles. SatRPV RNA was transmitted to Capsella bursa-pastoris plants by aphids only in the presence of BWYV and ST9a RNA. SatRPV RNA reduced accumulation of both BWYV helper and ST9a nonhelper RNAs in plants but did not affect symptoms. The replication of satRPV RNA only in the presence of subgroup II luteoviral RNAs but not in the presence of RNAs with subgroup I-like polymerase genes, in both monocotyledonous and dicotyledonous hosts, suggests that the specificity determinants of satRPV RNA replication are contained within the polymerase genes of supporting viruses rather than in structural genes or host plants.     

Characterization of hexose oxidase from the red seaweed Chondrus crispus

Hexose oxidase from the red seaweed, Chondrus crispus was purified to homogeneity. The enzyme appeared to be encapsulated in particles obtained after mechanical disintegration of the fronds. Liberation of the enzyme in soluble form required either waiting for the spontaneous development of a suitable microbial flora in the suspension, or treatment with a mixture of proteases (pronase). As deduced from (SDS/)PAGE, the enzyme has a molecular mass of 87 kDa and probably consists of subunits of 36 kDa and 25 kDa. The low isoelectric point of 2.8 and the presence of 25% (by mass) sugars indicate that the enzyme is a strongly acidic glycoprotein. The absorption spectrum of isolated enzyme minus that of the substrate-reduced enzyme, and the EPR spectrum of the free radical observed in the reduced enzyme revealed the presence of a flavin. This cofactor is probably covalently bound since flavins were not released upon denaturation of the enzyme by heat or acid treatment. Taking free FAD as a reference compound, the enzyme contains 1 mol flavin/mol enzyme. EPR spectroscopy of the purified preparation showed the presence of Cu2+. However, since the amount was substoichiometric, substrate addition did not affect the signal, and the addition of chelator or Cu2+ did not affect the activity, the presence of this metal ion seems adventitious. It is concluded that the large discrepancies between the presently and the previously reported [Sullivan, J. D. & Ikawa, M. (1973) Biochim. Biophys. Acta 309, 11-22] characteristics of the enzyme probably originate from the characterization of a contaminating protein in the latter case.     

Roaming through methodology. X. The testing of diagnostic procedures

In this era of evidence-based medicine, diagnostic tests cannot escape close scrutiny of their effectiveness. Sensitivity and specificity have up till now played a central role in the evaluation of diagnostic tests. These terms are not without their shortcomings when it comes to the characterisation of a test's true worth for patients. Randomised clinical trials are increasingly used for evaluation of medical tests and outlining of strategy. The indirect relationship between test results and health outcome creates additional challenges for designers of such trials.     

TFF1 gene expression in human medullary thyroid carcinoma

This epidemiological study investigated the reasons why children in Northern Ireland who need orthodontic treatment do not receive treatment even when it is provided free by the state. A total of 1584 15- and 16-year-olds were examined in 23 high schools with the Index of Orthodontic Treatment Need. The characteristics of the adolescents who had received orthodontic treatment were compared with those who had a definite need for treatment and yet did not receive treatment or advice. One in 10 of the adolescents examined had an unmet need for orthodontic treatment. Logistic regression analysis was used to assess the influence of 11 variables including socioeconomic status, religion, and standard of dental health on the uptake of orthodontic care. This analysis revealed that the only significant predictors of whether an adolescent received orthodontic treatment was the dental attendance pattern of the adolescent, the adolescent's dental health, and the dental attendance pattern of the adolescent's mother. Those adolescents who had good dental health, who regularly attended a dentist, and whose mother regularly attended a dentist were more likely to receive orthodontic treatment.     

Understanding the needs of children following large-scale disasters and the role of government

No one who experiences a disaster is untouched by it. Children and their families are often among the most affected. This article explains how mental health and medical professionals can assist families and communities in dealing with common disaster-related stress reactions in children. An overview of disaster research and examples of special concerns about children are given. In addition, an overview of the role of local, state, and federal governments, as well as other organizations, is provided.