Intracellular Synthesis of Myxovirus Neuraminidase in Chick Embryo Cell Monolayer Culture I. Neuraminidase Activity, Hemagglutinin Synthesis, and Content of Cell-bound Sialic Acid in Newcastle Disease Virus-infected Cells

Neuraminidase (Nase) activity of chick embryo monolayer cell homogenates was determined by its rate of splitting of neuraminlactose, free neuraminic acid (NA) being determined by the thiobarbituric acid assay. Noninfected cells were found to have no detectable amount of Nase activity. Newcastle disease virus (NDV)-infected cells (multiplicity of infection, 20 to 75 plaque-forming units per cell) displayed a high level of Nase synthesis, the rate of synthesis being parallel to that of hemagglutinin (HA) synthesis (with a 1.5 hr delay in the latter). An "eclipse" of the Nase and HA activities associated with the virus that was adsorbed onto cells was observed. The data provide evidence that the Nase is not incorporated into the viral envelope from a pre-existing cell supply but that its synthesis is coded by the viral genome. The content of cell-bound sialic acid, determined simultaneously in infected-cell homogenates, showed characteristic features allowing certain conclusions concerning the renewal of NA-terminating cell receptors during the course of infection, and the intracellular action of the Nase of the virus introduced into cells by the inoculum and that of the newly synthesized Nase at different stages of infection.     

Action of heparin on protein fractions of isolated nuclei and on their DNA content

Summary Isolated nuclei of rat hepatocytes were incubated with 0.05% sodium heparinate for 2 to 10 min. Alterations in the nuclei were controlled biochemically, determining the amounts of DNA and histones, and by cytophotometric methods determining the amounts of total and nonhistone proteins and DNA. Under the selected experimental conditions 95% of histones are bound already after 5-min incubation with heparin; nonhistone proteins of cell nuclei remain unchanged. The blockade of histones is followed by DNA diffusion into the incubation medium. Experiments with nuclear staining with alcian blue proved the specificity of heparin binding with histones and showed that heparin-histone complex remains in the nuclei, and its histones lose their extractability with 0.25 n HCl.     

Determination of tRNA nucleotide residues directly interacting with proteins in the post- and pretranslocated ribosomal complexes

Nucleotide residues of E. coli tRNA interacting directly with proteins in pre- and posttranslocated ribosomal complexes have been identified by analysis of photo-induced tRNA-protein cross-links. A9, G18, A26 and U59 residues of NAcPhePhe-tRNA, located in the Ab-site (pretranslocated complex) have been cross-linked with proteins S10, L27, S7 and L2 respectively. In deacylated tRNA, located in the Pb-site, residues C17, G44, C56 and U60 have been cross-linked with proteins L2, L5, L27 and S9 respectively. The G44-L5 cross-link disappeared after translocation (NAc-PhePhe-tRNA located in the Pt-site).     

Isochromosome X in man: Different DNA replication patterns in the long arms

Summary An X isochromosome for the long arm was studied in 3 patients with Turner's syndrome using the BrdUrd-Hoechst 33258-Giemsa method and C-staining. In all 3 patients studied, the long arms of the i(Xq) were asymmetrical with respect to chronology of DNA synthesis. The most striking asynchrony of DNA replication was observed in large early replicating segments adjacent to the centromeric region. Two C bands of similar appearance were observed localized symmetrically in both arms. The data are interpreted in accordance with two possible origins of an abnormal X which is known as i(Xq).     

Dependence of heterochromatin differential staining on the time of its reduplication and the degree of condensation]

A comparison of the chromosomes banding pattern after G-and C-staining with the time of DNA reduplication and the degree of chromosome condensation, was carried out using Chinese hamster metaphase chromosomes. Chromosome condensation was studied under 5-bromodeoxyuridine and 5-bromodeoxycytidine treatment. All the chromosomal segments stained with C-technique are also stainable with G-technique, while only some G-positive segments are capable to be C-bands. C-bands are heterochromatic segments characterized by extremely late replication and great delay in condensation under the analog action, while G-bands are segments with earlier labelling and irregular decondensation. The data obtained suggest a close correlation between the capability of chromosomal region of G- and C- staining and the degree of its heterochromatinization.     

Isolation and purification of restriction endonuclease BpeI from Bordetella pertussis

New restriction endonuclease has been isolated from Bordetella pertussis vaccine strain 305 and purified in 1 stage on Sepharose covalently bound with blue dextran. The isolated restrictase has been found capable of breaking down lambda-phag DNA into 7 fragments. According to its specificity, Bpe I is the isoschizomer of Hind III obtained from Haemophilus influenzae strain Rd.     

Quantitative assessment of human chromosomal polymorphism with regard to paracentromeric heterochromatin

The measurement of C-segment length in chromosomes 1, 9 and 16 of 7 individuals was carried out. The regression analysis was employed to study a change of the C-segment sizes in the process of mitotic chromosome condensation. Typical values of C-segment length for chromosomes 1, 9 and 16 are about 1.4, 1.1 and 0.8mu respectively. Among 7 individuals there was no two which had identical size of C-segments for all three chromosomes studied. In six individuals heteromorphysm of C-segments was revealed. It was found that visually detected heteromorphysm may be expressed quantitatively as ratio length of C-segments in homologous chromosomes.     

Membrane and protein properties of freeze-dried mouse platelets

Membrane properties and the overall protein secondary structure of freeze-dried trehalose-loaded mouse platelets were studied using steady state fluorescence anisotropy and Fourier transform infrared spectroscopy (FTIR). FTIR results showed that fresh control mouse platelets have a main phase transition at ~14°C, whereas, freeze-dried platelets exhibited a main phase transition ~12°C. However, the cooperativity of the transition of the rehydrated platelets was greatly enhanced compared to that of control platelets. Anisotropy experiments performed with 1,6 diphenyl-1,3,5 hexatriene (DPH) complemented FTIR results and showed that the lipid order in the core of the membrane was affected by freeze-drying procedures. Similar experiments with trimethyl ammonium 1,6 diphenyl-1,3,5 hexatriene (TMA-DPH), a membrane surface probe, indicated that membrane properties at the membrane/water interface were less affected by freeze-drying procedures than the core of the membrane. Lyophilization did not result in massive protein denaturation, but the overall protein secondary structure was altered, based on in situ assessment of the amide-I and amide-II band profiles. Lyophilization-induced changes to endogenous platelet proteins were further investigated by studying the protein's heat stability. In fresh control platelets, proteins denatured at 42°C, whereas proteins in the rehydrated platelets denatured at 48°C.     

Somatoform disorders among patients attending walk-in clinics in Trinidad: prevalence and association with depression and anxiety

Objectives Somatoform disorders are common in international primary care settings, but have been little studied in the developing world. The objective of this study was to determine the prevalence of severe undifferentiated somatoform disorder, and its relationship to depression and anxiety, among patients attending walk-in clinics in Trinidad.Methods The study participants, who were all aged 18 years or older and attending walk-in clinics at 16 randomly selected health centres, were surveyed between May and August 2007 using the PRIME-MD questionnaire.Results There were 594 participants (the response rate was 92%), of whom 72.7% were female. Their ages ranged from 18 to 93 years, and 54.5% were over 50 years of age. In total, 37.2% were married and 25.9% were single. Indo-Trinidadians represented 43.1% and Afro-Trinidadians represented 36% of the study sample; 56.5% of the participants reported that their income was less than US$ 400 per month, and 65.7% were unemployed. At walk-in clinics in Trinidad, the estimated prevalence of severe undifferentiated somatoform disorder was 10.3% (95% CI: 7.86–12.74), that of hypochondriasis was 28.5% (95% CI: 24.9–32.1), and that of body dysmorphic disorder was 15.8% (95% CI: 11.9–18.7). Severe undifferentiated somatoform disorder was statistically significantly associated with gender and ethnicity but not with age, level of education, employment status or income. Chi-square testing found significant associations between the presence of severe undifferentiated somatoform disorder and both depression and anxiety (P < 0.05), between hypochondriasis and both anxiety and depression (P < 0.05), and between body dysmorphic disorder and depression (P < 0.05) but not anxiety. Regression analysis suggested that the demographic features that predicted severe undifferentiated somatoform disorder were being female or Indo-Trinidadian.Conclusions Walk-in clinics in Trinidad that serve older patients on a lower income have a high proportion of patients with somatoform disorders as measured by the PRIME-MD scale. These patients exhibit many features of anxiety and depression. These findings have implications for medical training and service delivery.