Polynucleotide phosphorylase is a component of a novel plant poly(A) polymerase

We have isolated cDNA clones encoding a novel RNA-binding protein that is a component of a multisubunit poly(A) polymerase from pea seedlings. The encoded protein bears a significant resemblance to polynucleotide phosphorylases (PNPases) from bacteria and chloroplasts. More significantly, this RNA-binding protein is able to degrade RNAs with the resultant production of nucleotide diphosphates, and it can add extended polyadenylate tracts to RNAs using ADP as a donor for adenylate moieties. These activities are characteristic of PNPase. Antibodies raised against the cloned protein simultaneously immunoprecipitate both poly(A) polymerase and PNPase activity. We conclude from these studies that PNPase is the RNA-binding cofactor for this poly(A) polymerase and is an integral player in the reaction catalyzed by this enzyme. The identification of this RNA-binding protein as PNPase, which is a chloroplast-localized enzyme known to be involved in mRNA 3'-end determination and turnover (Hayes, R., Kudla, J., Schuster, G., Gabay, L., Maliga, P., and Gruissem, W. (1996) EMBO J. 15, 1132-1141), raises interesting questions regarding the subcellular location of the poly(A) polymerase under study. We have reexamined this issue, and we find that this enzyme can be detected in chloroplast extracts. The involvement of PNPase in polyadenylation in vitro provides a biochemical rationale for the link between chloroplast RNA polyadenylation and RNA turnover which has been noted by others (Lisitsky, I., Klaff, P., and Schuster, G. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 13398-13403).     

Caspase-3 is required for DNA fragmentation and morphological changes associated with apoptosis

Interleukin 1beta-converting enzyme-like proteases (caspases) are crucial components of cell death pathways. Among the caspases identified, caspase-3 stands out because it is commonly activated by numerous death signals and cleaves a variety of important cellular proteins. Studies in caspase-3 knock-out mice have shown that this protease is essential for brain development. To investigate the requirement for caspase-3 in apoptosis, we took advantage of the MCF-7 breast carcinoma cell line, which we show here has lost caspase-3 owing to a 47-base pair deletion within exon 3 of the CASP-3 gene. This deletion results in the skipping of exon 3 during pre-mRNA splicing, thereby abrogating translation of the CASP-3 mRNA. Although MCF-7 cells were still sensitive to tumor necrosis factor (TNF)- or staurosporine-induced apoptosis, no DNA fragmentation was observed. In addition, MCF-7 cells undergoing cell death did not display some of the distinct morphological features typical of apoptotic cells such as shrinkage and blebbing. Introduction of the CASP-3 gene into MCF-7 cells resulted in DNA fragmentation and cellular blebbing following TNF treatment. These results indicate that although caspase-3 is not essential for TNF- or staurosporine-induced apoptosis, it is required for DNA fragmentation and some of the typical morphological changes of cells undergoing apoptosis.     

Subject''s perceptions of the crew interaction dynamics under prolonged isolation

BACKGROUND: Short-term variability of RR interval and blood pressure occurs predominantly at low frequency (LF; approximately 0.1 Hz) and high frequency (approximately 0.25 Hz). The arterial baroreflex is thought to be the predominant determinant of the LF component of RR variability. Patients with severe congestive heart failure (CHF) have an attenuated or absent LF oscillation in RR variability. The left ventricular assist device (LVAD) offers a unique possibility for analysis of spectral oscillations in RR interval independent of any effects of blood pressure that influence these oscillations via the baroreflex. METHODS AND RESULTS: We performed spectral analysis of RR, blood pressure, and respiration in 2 patients with CHF before and after LVAD implantation. LF components of the RR-interval and blood pressure variability were absent in both CHF patients before LVAD implantation. After LVAD implantation, spectral analysis of the RR interval showed restoration of a clear and predominant LF oscillation in the native hearts of both patients, with no such oscillation evident in the blood pressure profile. CONCLUSIONS: During total circulatory support with the LVAD, the LF oscillation in RR interval of the native heart, absent in CHF, is restored. This LF oscillation in RR interval occurs in the absence of LF oscillations in blood pressure and thus is unlikely to be explained by baroreflex mechanisms. Hence, the absence of LF oscillation in the RR interval in CHF is functional and is reversible by LVAD circulation. The presence of a predominant LF oscillation in RR interval independent of any oscillation in blood pressure suggests that the LF oscillation is a fundamental property of central autonomic outflow.     

Cultural and linguistic barriers to mental health service access: the deaf consumer's perspective

OBJECTIVE: The authors investigated knowledge, attitudes, and beliefs about mental illness and providers held by a group of deaf adults. METHOD: The American Sign Language interviews of 54 deaf adults were analyzed. RESULTS: Recurrent themes included mistrust of providers, communication difficulty as a primary cause of mental health problems, profound concern with communication in therapy, and widespread ignorance about how to obtain services. CONCLUSIONS: Deaf consumers' views need due consideration in service delivery planning. Outreach regarding existing programs is essential.     

Role of cytokines in AIDS wasting

There is now a large literature implicating cytokines in the development of wasting and cachexia commonly observed in a variety of pathophysiologic conditions. In the acquired immunodeficiency syndrome (AIDS), cytokines elicited by primary and secondary infections seem to exert subtle and sustained effects on behavioral, hormonal, and metabolic axes, and their combined effects on appetite and metabolism have been postulated to drive wasting. However, correlations of increased blood levels of a particular cytokine with wasting in AIDS have not been consistent observations, perhaps because cytokines act principally as paracrine and autocrine hormones, as well as indirectly by activating other systems. A better understanding of the mechanisms underlying the catabolic effects of cytokines in clearly needed if more efficacious strategies are to be developed for the prevention and treatment of wasting in AIDS. In this review we first examine the interacting factors contributing to the AIDS wasting syndrome. We then analyze the complex and overlapping role of cytokines in the pathophysiology of this condition, and put forward a number of hypotheses to explain some of the most important features of this syndrome.     

Experience in using at a polyclinic the Siberia low-dose digital X-ray unit

Application interactive CLASS software for stimulating productive binocular cooperation based on random-dot patterns and stereograms was used for treating strabismus and amblyopia in 105 children during a standard course of treatment. The children were divided into 3 groups treated by the CLASS alone (1), Class + two other application programs (2), and CLASS + traditional methods. General positive changes (improvement of visual acuity, decrease of eye deviation, etc.) were similar in these 3 groups. Positive effect of CLASS exercises on binocular visual mechanisms was significant. Due to precise evaluation of binocular interaction provided by CLASS, positive changes in binocular cooperation and stereovision were attained in 93% of children.     

The effect of constant baroque music on premature infants

A rapid and simple method for the in vitro evaluation of the virulence of F. tularensis is proposed. The optimal parameters--the concentrations of bacteria and the substrate (phenolphthalein phosphate), the time incubation in the serum--have been developed and special conditions for strains of different subspecies have been selected. The proposed method makes it possible to greatly reduce the time of obtaining results and to exclude labor-consuming experiments on laboratory animals when working with large collections of F. tularensis laboratory and natural wild strains. Moreover, the method widens the possibilities of experimenters in the evaluation of the effect of some mutation on the virulence of the strain under study.     

High-dose busulphan/melphalan with autologous stem cell rescue in Ewing's sarcoma

Eighteen patients with poor risk Ewing's sarcoma (including 11 patients with metastatic disease at presentation) received consolidation therapy of busulphan and melphalan with autologous stem cell rescue. There were nine females. The median age at diagnosis was 14.2 years (range 2.75-30 years). There was one early death due to cytomegalovirus pneumonitis. One patient developed a single generalised convulsion during busulphan therapy. Severe renal toxicity was not encountered. One patient developed veno-occlusive disease of the liver (VOD) which eventually resolved. With a median follow up of 2 years, 13 patients survive including six with initial metastatic disease. We conclude that high-dose busulphan/melphalan is well-tolerated and should be evaluated for efficacy in a larger series of patients with high risk Ewing's sarcoma.     

Varietal differences for reaction to high soil acidity and to trace elements; a survey of research in The Netherlands

A review, concerning varietal differences for reaction to high soil acidity in cereals and to trace elements in different crops is presented. Techniques to be used in selection for tolerance to low soil pH are described.A preliminary version of this paper is published as a chapter in the volumeEfficient use of Fertilizers in Agriculture, Dev Plant and Soil Sc., vol 10, 1983. Martinus Nijhoff/Dr W. Junk Publishers, The Hague. The present publication inFertilizer Research should be cited as original source of publication.