Changes in intracellular levels of Ap3A and Ap4A in cysts and larvae of Artemia do not correlate with changes in protein synthesis after heat-shock.

Artemia larvae respond to a brief heat-shock between 28 degrees and 40 degrees C with an increase in the synthesis of two groups of proteins of Mr 68,000 and 89,000. At 40 degrees C synthesis of all other proteins is strongly repressed. Cysts, which are naturally thermotolerant, synthesise both heat-shock proteins at temperatures up to 47 degrees C but maintain normal protein synthesis. During pre-emergence development, Ap3A is present in cysts at a concentration twice that of Ap4A. The maximum level of 7.6 pmol/10(6) cells is reached shortly before hatching of the larvae. After hatching, the levels of both nucleotides decline. A 40 degrees C heat-shock produces a 1.8-fold increase in both nucleotides within 20 min in cysts and larvae. A 2.8-fold increase results from a 47 degrees C heat-shock to cysts. The rates of increase parallel but do not precede the increases in the heat-shock proteins. Since non-heat-shocked cysts possess higher levels of Ap3A and Ap4A than do heat-shocked larvae, the observed heat-induced changes in gene expression cannot be explained simply in terms of the intracellular concentrations of these nucleotides.     

Size of motoneuron pool may be related to number of myotubes in developing muscle

The number of myotube clusters in various chicken hindlimb muscles has been counted at the time of motoneuron cell death and found to be quantitatively similar to the number of neurons which innervate these muscles in the adult. It is proposed that the capacity of a muscle to support motoneurons is related to the number of “myotube clusters” in that muscle at the time of motoneuron cell death.     

The natural history of childhood asthma to adult life.

A randomly selected group of 331 children who had started to wheeze in childhood and a control group of 77 children were prospectively studied clinically and physiologically from 7 to 21 years of age. Most subjects improved during adolescence and about 55% of those whose wheezing had started before 7 years and stopped before adolescence remained wheeze free. Forty-five per cent of subjects who had apparently ceased to wheeze at 14 years had minor recurrences of wheezing between 14 and 21 years of age. Fewer than 20% of those with persistent symptoms in childhood had become totally wheeze free during adolescence, although there was amelioration in symptoms. Girls did less well during adolescence than boys, so that there was no longer an increased preponderance of boys with increasing severity of asthma. Normal growth was achieved in all grades despite the persistence of symptoms in many cases. At 21 years of age features of airways obstruction were often found during an interval phase, especially in those who had more persistent symptoms.     

Extending phylogenetic studies of coevolution: secondary Brooks parsimony analysis, parasites, and the Great Apes

Dowling recently compared the empirical properties of Brooks parsimony analysis (BPA) and the leading method for studying phylogenetic aspects of coevolution, reconciled tree analysis (using the computer program TreeMap), based on a series of simulations. Like the majority of authors who have compared BPA with other methods, however, Dowling considered only the form of BPA proposed in 1981 and did not take into account various modifications of the method proposed from 1986 to 2002. This leaves some doubt as to the robustness of his assessments of both the superiority of BPA and its shortcomings. We provide a précis of the principles of contemporary BPA, including ways to implement it algorithmically, using either Wagner algorithm‐based or Hennigian argumentation‐based approaches, followed by an empirical example. Our study supports Dowling's fundamental conclusions about the superiority of primary BPA relative to TreeMap. However, his conclusions about the shortcomings of BPA due to inclusive ORing (i.e., the production of ghost taxa) are incorrect, as secondary BPA eliminates inclusive ORing from the method. Secondary BPA provides a more complete account of the evolutionary associations between the parasite groups and their hosts than does primary BPA, without sacrificing any indirectly generated information about host phylogeny. Secondary BPA of two groups of nematodes inhabiting Great Apes shows that TreeMap analysis underestimated the amount of cospeciation in the evolution of the nematode genus Enterobius.     

Monocyte antibody-dependent cellular cytotoxicity in splenectomized subjects

Monocyte antibody-dependent cellular cytotoxicity (ADCC) was determined in normal subjects by using human A1 erythrocytes and immune human anti-A1 antiserum. The experimental data were fitted to a mathematical model and the values for maximal cytotoxicity and monocyte numbers required to produce 15% specific cytotoxicity (MD15) were subsequently computed and compared with the values for these two parameters estimated from the dose response curves. The values for both were significantly associated, and the mathematical model permitted precise quantitation of cytotoxicity in instances where this was impossible by standard methods. Maximal monocyte ADCC was significantly reduced in a group of splenectomized subjects, whereas the MD15 was increased. These findings emphasize the possible influences of the method of quantitation of ADCC and provide one explanation for the apparent conflict of published data.     

Influence of dietary lipids on arrhythmias and infarction after coronary artery ligation in rats

Coronary artery ligation (CAL) was used to produce an in vivo model of cardiac arrhythmias and myocardial infarction using anaesthetized male Hooded Wistar rats which had been fed for 6-7 or 18-20 months on either a standard reference diet alone or supplemented (12% w/w) with sunflower seed oil (linoleic acid rich) or sheep kidney fat (linoleic acid poor). The number of ventricular extra beats and duration of tachycardia or fibrillation in the 30-min postligation was increased in sheep kidney fat-fed rats. Infarct size 4 h postCAL was reduced in sunflower seed oil-fed rats. Arrhythmias, infarct size, and dietary-induced differences were increased with age. The diets employed produce changes in myocardial membrane phospholipids which could result in altered prostaglandin production. These results show that in the rat (as in man), age and dietary saturated fat are risk factors for sudden cardiac death and myocardial infarction and suggest that the rat is a useful model for the investigation of dietary interventions in heart disease.     

Spawning behaviour of taimen (<Emphasis Type="Italic">Hucho taimen</Emphasis>) from the Uur River,Northern Mongolia

This study presents the first observations of Hucho taimen spawning in the wild based on underwater video recordings. One pair of taimen was monitored during a 19 h period, supplemented with visual observations from two other spawning pairs. We recorded two full spawning events performed in two different locations separated by approximately 30 m. The absence of an established male hierarchy along a nesting female was the most important difference between taimen and other salmonine breeding biology. Taimen spawning, based on our observations, is a single pair event. The male prevented the approach of other males by launching intense attacks that extended for several meters away from the redd. Our data suggests that taimen females, differently from other salmonines, do not cover their eggs immediately after having spawned but rest for a variable number of minutes before covering them.     

PET/CT Assessment of Response to Therapy: Tumor Change Measurement,Truth Data,and Error

We describe methods and issues that are relevant to the measurement of change in tumor uptake of ¹⁸F-fluorodeoxyglucose (FDG) or other radiotracers, as measured from positron emission tomography/computed tomography (PET/CT) images, and how this would relate to the establishment of PET/CT tumor imaging as a biomarker of patient response to therapy. The primary focus is on the uptake of FDG by lung tumors, but the approach can be applied to diseases other than lung cancer and to tracers other than FDG. The first issue addressed is the sources of bias and variance in the measurement of tumor uptake of FDG, and where there are still gaps in our knowledge. These are discussed in the context of measurement variation and how these would relate to the early detection of response to therapy. Some of the research efforts currently underway to identify the magnitude of some of these sources of error are described. In addition, we describe resources for these investigations that are being made available through the Reference Image Database for the Evaluation of Response project. Measures derived from PET image data that might be predictive of patient response as well as the additional issues that each of these metrics may encounter are described briefly. The relationship between individual patient response to therapy and utility for multicenter trials is discussed. We conclude with a discussion of moving from assessing measurement variation to the steps necessary to establish the efficacy of PET/CT imaging as a biomarker for response.     

Analysis of non-TIR NBS-LRR resistance gene analogs in <Emphasis Type="Italic">Musa acuminata</Emphasis> Colla: Isolation,RFLP marker development,and physical mapping

Background  

Many commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives, by contrast, possess greater variability and represent potential sources of disease resistance genes (R-genes). The largest known family of plant R-genes encode proteins with nucleotide-binding site (NBS) and C-terminal leucine-rich repeat (LRR) domains. Conserved motifs in such genes in diverse plant species offer a means for isolation of candidate genes in banana which may be involved in plant defence.