The N-terminal side of the origin-binding domain of simian virus 40 large T antigen is involved in A/T untwisting

We investigated the role of the N-terminal side of simian virus 40 (SV40) large T antigen's origin-binding domain in the initiation of virus DNA replication by analyzing the biochemical activities of mutants containing single point substitutions or deletions in this region. Four mutants with substitutions at residues between 121 and 135 were partially defective in untwisting the A/T-rich track on the late side of the origin but were normal in melting the imperfect palindrome (IP) region on the early side. Deletion of the N-terminal 109 amino acids had no effect on either activity, whereas a longer deletion, up to residue 123, greatly reduced A/T untwisting but not IP melting. These results indicate that the region from residue 121 to 135 is important for A/T untwisting but not for IP melting and demonstrate that these activities are separable. Two point substitution mutants (126PS and 135PL) were characterized further by testing them for origin DNA binding, origin unwinding, oligomerization, and helicase activity. These two mutants were completely defective in origin (form U(R)) unwinding but normal in the other activities. Our results demonstrate that a failure to normally untwist the A/T track is correlated with a defect in origin unwinding. Further, they indicate that some mutants with substitutions in the region from residue 121 to 135 interact with origin DNA incorrectly, perhaps by failing to make appropriate contacts with the A/T-rich DNA.     

Color Doppler ultrasound criteria to diagnose varicoceles: correlation of a new scoring system with physical examination

Mitochondrial aldehyde dehydrogenase (ALDH2) is mainly responsible for the oxidation of acetaldehyde generated during alcohol oxidation in vivo. Cytochrome P-4502E1 (CYP2E1), a liver microsomal enzyme, also metabolizes acetaldehyde and ethanol. Genetic polymorphism of ALDH2 and CYP2E1 was investigated among 481 Korean adults. A new restriction fragment-length polymorphism method was developed to determine the genotype of the ALDH2 alleles. This method proved to be simpler and faster than the hybridization method using allele-specific oligonucleotide probes and polymerase chain reaction-directed mutagenesis. The allele frequencies of ALDH2(1) and ALDH2(2) were 0.840 and 0.160, respectively. This allele frequency of ALDH2(2) is less than in Japanese people. Genetic polymorphism of CYP2E1 was investigated using polymerase chain reaction and restriction fragment-length polymorphism. The estimated allele frequencies for c1 and c2 were 0.808 and 0.192.     

Coping with crises: an examination of the impact of traumatic events on religious beliefs

The impact of traumatic events on empirical and metaphysical assumptions was examined, by comparing assumptions of a group of 25 persons who had recently experienced a major stressor with assumptions of a group of 25 persons who had not had such an experience. Each group was composed of 22 women and 3 men, with a mean age of 20 years. Participants completed written measures assessing levels of adjustment, empirical world assumptions, religious motivation, and religious and spiritual experiences. Naturalistic interviews were conducted with the trauma group. The trauma group obtained significantly higher scores on symptoms of psychological distress but did not differ in evaluations of the empirical world as predictable, safe, or controllable. Interviews suggested that the metaphysical assumptions were not challenged by trauma; rather, they provided a framework for understanding and coping with trauma.     

Carbonic anhydrase II deficiency: single-base deletion in exon 7 is the predominant mutation in Caribbean Hispanic patients

To date, three different structural gene mutations have been identified in patients with carbonic anhydrase II deficiency (osteopetrosis with renal tubular acidosis and cerebral calcification). These include a missense mutation (H107Y) in two families, a splice junction mutation in intron 5 in one of these families, and a splice junction mutation in intron 2 for which many Arabic patients are homozygous. We report here a novel mutation for which carbonic anhydrase II-deficient patients from seven unrelated Hispanic families were found to be homozygous. The proband was a 2 1/2-year-old Hispanic girl of Puerto Rican ancestry who was unique clinically, in that she had no evidence of renal tubular acidosis, even though she did have osteopetrosis, developmental delay, and cerebral calcification. She proved to be homozygous for a single-base deletion in the coding region of exon 7 that produces a frameshift that changes the next 12 amino acids before leading to chain termination and that also introduces a new MaeIII restriction site. The 27-kD truncated enzyme produced when the mutant cDNA was expressed in COS cells was enzymatically inactive, present mainly in insoluble aggregates, and detectable immunologically at only 5% the level of the 29-kD normal carbonic anhydrase II expressed from the wild-type cDNA. Metabolic labeling revealed that this 27-kD mutant protein has an accelerated rate of degradation. Six subsequent Hispanic patients of Caribbean ancestry, all of whom had osteopetrosis and renal tubular acidosis but who varied widely in clinical severity, were found to be homozygous for the same mutation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Radioimmunoconjugates in the detection of infection and inflammation

Various nuclear medicine techniques are widely used to image foci of infection and inflammation. Among the relatively new radiopharmaceuticals for this purpose are radioimmunoconjugates such as labeled murine monoclonal antigranulocyte antibodies and labeled human polyclonal nonspecific immunoglobulin G. This article reviews some background information, mechanism of action, side effects, biodistribution, kinetics, results of clinical studies, and dosimetry of several radioimmunoconjugates both of murine monoclonal and human polyclonal origin. The efficacy of these agents has been demonstrated in a variety of clinical conditions. Radiolabeled immunoconjugates may emerge as convenient alternatives to the present technique of choice: in vitro blood cell labeling techniques with their inherent problems and risks.     

Effects of 6-hydroxydopamine and pimozide on temperature maintenance by the chicken

Intraventricular implants of pimozide in adult white leghorn hens were used to block dopamine (DA) receptors, and 6-hydroxydopamine (6-OHDA) was injected intraventricularly to destroy the noradrenergic system locally. The hens were exposed to ambient temperatures of 5 and 35 degrees C, and their core temperature was measured. One hundred micrograms of 6-OHDA significantly reduced the norepinephrine (NE) but not the DA content of the hypothalamus and reduced the uptake of [3H]NE but not of [3H]DA by synaptosomes in vitro. Neither of the drug treatments nor their combination affected average core body temperature (Tb) at either 5 or 35 degrees C. Pimozide treatment caused a lower maximum Tb at 35 degrees C and a higher maximum Tb at 5 degrees C than the control treatment. No evidence was obtained that 6-OHDA treatment affected body temperature regulation. It is concluded that neither the DA nor the NE system is essential for normal temperature maintenance in the hen exposed to either 5 or 35 degrees C.     

Influence of iron-limited continuous culture on physiology and virulence of Legionella pneumophila

A virulent strain of Legionella pneumophila serogroup 1, subgroup Pontiac, was grown in continuous culture at a constant growth rate under iron-replete and iron-limited conditions. Iron limitation was achieved by the removal of ferrous sulfate and hemin from the chemically defined medium. Residual contaminating iron, 0.45 microM, was sufficient to support iron-limited growth. Typical iron-replete cultures metabolized 3.3 microM iron. Serine provided the principal source of carbon and energy for both cultures, although iron-replete cultures also depleted a number of other amino acids. There was a 40% decrease in culture biomass under iron-restricted conditions. Iron limitation did not significantly affect carbohydrate metabolism, with the molar growth yield for carbon (Ycarbon) comparable for both cultures. However, under iron-limited conditions a sixfold increase in Yiron correlated with a significant decrease in the iron content of the biomass, as the culture utilized the available iron more efficiently. Highly pleomorphic iron-replete cultures became uniform cultures of short fine rods when adapted to iron-deficient conditions. In addition to the morphological and physiological changes, iron limitation had a critical effect on culture virulence. The virulence of this strain was significantly (P < 0.05) reduced when the culture was subjected to iron-limited conditions. This phenomenon was reversible, with a significant increase in culture virulence upon reversion to iron-replete conditions. When compared in an in vitro macrophage assay, the number of culturable avirulent iron-limited cells located intracellularly after infection was significantly lower than for the virulent replete and control cultures. These results further support the role of environmental parameters in regulating the virulence of L. pneumophila.     

Antitumor activity of five new platinum complexes having a glycolate leaving ligand

Ganglioside GM3, one of acidic components of membrane glycosphingolipids (GSL), has been known to change its content quantitatively during growth and differentiation of various cells in vitro. Detailed analysis of lipid portion of GM3 of rat renal glomerular SGE1 cells revealed that fatty acids with long carbon chains, especially that of C24:0 and C24:1 increased, while that of short C18:0 and C20:0 decreased after spontaneous dome formation. Since not only fatty acid composition of neutral GSL, sulfatide and phospholipid but also composition of long-chain bases (LCB) did not change, it was suggested that only C24 fatty acid of GM3 specifically increased in relation to dome formation. The spontaneous dome formation has been reported to be related with induction of cellular differentiation in many transporting epithelial cells. We thus assume that the change of fatty acid composition of GM3 is involved in cellular differentiation of SGE1 cells.