Empty capsids from adenovirus, that is, virus particles lacking DNA, are well documented in the published literature. They can be separated from complete virus by CsCl density gradient centrifugation. Here we characterize the presence of empty capsids in recombinant adenovirus preparations purified by column chromatography. The initial purified recombinant adenovirus containing the p53 tumor suppressor gene was produced from 293 cells grown on microcarriers and purified by passage through DEAE-Fractogel and gel-filtration chromatography. Further sequential purification of the column-purified virus by CsCl and glycerol density gradient centrifugations yielded isolated complete virus and empty capsids. The empty capsids were essentially noninfectious and free of DNA. Analysis of empty capsids by SDS-PAGE or RP-HPLC showed the presence of only three major components: hexon, IIIa, and a 31K band. This last protein was identified as the precursor to protein VIII (pVIII) by mass spectrometric analysis. No pVIII was detected from the purified complete virus. Analysis by electron microscopy of the empty capsids showed particles with small defects. The amount of pVIII was used to determine the level of empty capsid contamination. First, the purified empty capsids were used to quantify the relation of pVIII to empty capsid particle concentration (as estimated by either light scattering or hexon content). They were then used as a standard to establish the empty capsid concentration of various recombinant adenovirus preparations. Preliminary research showed changes in empty capsid concentration with variations in the infection conditions. While virus purification on anion-exchange or gel-filtration chromatography has little effect on empty capsid contamination, other chromatographic steps can substantially reduce the final concentration of empty capsids in column-purified adenovirus preparations.
We examined the change in Swiss suicide rates since 1969, breaking down the rates according to the method used. The descriptive analyses of the main suicide methods are presented. The suicide rates reached a peak in the late 1970s/early 1980s and declined in more recent years. Firearm suicides and suicides by falls were the exception and sustained their upwards trend until the 1990s. Suicide by vehicle exhaust asphyxiation showed a rapid decline following the introduction of catalytic converters in motor vehicles. No substantial method substitution was observed. Suicide by poisoning declined in the 1990s but rose again following an increase in assisted suicide in somatically incurable patients. Suicide is too often regarded as a homogeneous phenomenon. With regard to the method they choose, suicide victims are a heterogeneous population and it is evident that different suicide methods are chosen by different people. A better understanding of the varying patterns of change over time in the different suicide methods used may lead to differentiated preventive strategies.
Matricide, the killing of mothers by their biological children, is a very rare event, comprising less that 2% of all U.S. homicides in which the victim-offender relationship is known. This manuscript examines more than 20 years of U.S. homicides to determine the age and gender characteristics of matricide offenders. These data reveal that most mothers are killed by their adult sons. Daughters younger than 18 years are the most infrequent killers of mothers. This article examines the incidence of parricide, the involvement of sons and daughters in matricidal incidents, and synthesizes the literature in terms of offender gender. Special attention is given to female matricide offenders, given the lack of research currently available with respect to this population. Implications for practice, policy, and research are discussed.
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