In vitro assembly of infectious nucleocapsids of bacteriophage phi 6: formation of a recombinant double-stranded RNA virus.

A system is described for assembling infectious bacteriophage phi 6 nucleocapsids in vitro. Procapsids encoded by cDNA copies of genomic segment L in Escherichia coli were used to package and replicate viral RNA segments. The resulting filled particles were shown to be capable of infecting host cell spheroplasts after incubation with purified nucleocapsid shell protein P8. The infected spheroplasts yielded infectious virions. A modified cDNA-derived RNA segment was inserted into virions by this method. The resulting infectious virions contained the same 4-base-pair deletion as the modified cDNA. These findings support the contention that the preformed procapsids are the "machine" that replicates the phi 6 genome, by showing that the cDNA-derived procapsids are competent to package and replicate RNA properly.     

Doppler evaluation of blood flow of the lower limb

Regional blood flow measurement in the limbs (BFLL) is of special interest in order to evaluate the consequences of hypertension. The purpose of this study is to assess the interest of the Doppler ultrasound method in the BFLL measurement among normotensive or borderline hypertensives young male adults. BFLL reproducibility was evaluated among 23 healthy subjects aged 21 +/- 2 y, height 177 +/- 8 cm, weight 75 +/- 13 kg at day one (D1) and three day later (D3). Measurements were made basically after 20 minutes lying at rest and after cold pressor test (CPT). BFLL estimation depends on common femoral artery diameter (FAD) echographic measurement at the thigh root and on velocity time interval (VTI) calculation with pulsed wave doppler using controlled incident angle and sample volume. The following parameters were measured: mean arterial pressure (MAP) using Dinamap, heart rate (HR), FAD, common femoral artery cross sectorial area (A), VTI and peripheral arteriolar resistances (PAR). Basic and CPT results at D1 and D3 were compared using paired "t" test. Results: [table: see text] Comparisons between basic state and CPT demonstrate a significant decrease of VTI and BFLL, a significant increase of PAR. D remained unchanged. Doppler ultrasound method is easy to use. Systolic femoral volume measurement is relatively insensitive to small transducer positioning variations so that the method reproducibility is satisfactory.     

Universally conserved and yeast-specific U1 snRNA sequences are important but not essential for U1 snRNP function

To study the contribution of the large, 568-nucleotide yeast (Saccharomyces cerevisiae) U1 snRNA to pre-mRNA splicing, we generated mutations in two regions of the molecule and introduced each mutant gene back into yeast as the sole copy of the U1 snRNA gene. We mutagenized the "A loop," a subregion highly conserved in primary sequence in all U1 snRNA molecules analyzed to date. We also mutagenized a portion of the yeast core subdomain, a region conserved in primary and secondary structure among several yeast species but absent from the much smaller metazoan U1 molecule. Surprisingly, mutations in these two regions had little or no effect on growth rate, yet several of them affected an inefficiently spliced reporter gene construct. In addition, combinations of mutants in both regions gave rise to reduced growth rates. Using the latter assay, we confirmed some of the proposed secondary structure of the yeast core domain. The experiments indicate that both regions contribute to U1 snRNP activity but that mutations in a single region do not have a substantial effect on growth rate because U1 snRNP activity is not rate-limiting for growth.     

Scanning electron microscopic observations on larvae and young adults of Angiostrongylus cantonensis

Scanning electron microscopic observations on the structure of the body surface of various larval stages and young adults of Angiostrongylus cantonensis were made. The mouth opening of the first and second stage larvae closes in "Y" form until well developed young adult stage. There are two rows of 6 sensory papillae each around the mouth. With development of the worm, the papillae of the outer row gradually degenerated and could hardly be seen in adult worms. A pair of amphidial pores was present on the external side of lateral papillae of the inner row, being conspicuous in the fourth-stage larvae. There was one excretory pore on the ventral side of the anterior end. The copulatory bursa of the male worms began to develop in the third stage larvae and became well developed in the 25-day young adults. The processes of the development of copulatory bursa were described. The gonopore could be seen in the female worm as early as in the first-stage larvae but the anal pore appeared only in the fourth-stage larvae, both of them did not develop completely until the young adult stage of 11 day old (Figs. 1-18).     

Inhibition of two imidazole antimycotics, eberconazole and clotrimazole, by different components of Candida albicans serotype B membrane protoplasts

The inhibitory activity of different components from Candida albicans membrane protoplasts against clotrimazole and eberconazole was studied. The phospholipid fraction had the most inhibitory activity and the antimycotic activity of eberconazole was more affected than that of clotrimazole.     

Behavioral sensitization to MK-801 (dizocilpine): neurochemical and electrophysiological correlates in the mesoaccumbens dopamine system

MK-801, a non-competitive antagonist at the N-methyl-D-aspartate (NMDA) subtype of central glutamate receptor, stimulates locomotor activity in rats. Administration of MK-801 (0.25mg/kg, i.p.) on four consecutive days results in progressive sensitization of its locomotor stimulatory effects. Because of the importance of dopamine (DA) systems in locomotor sensitization to other stimulants (e.g. amphetamine and cocaine), we examined the possible role of DA transmission in MK-801 sensitization. The D1 antagonist SCH 23390 was used for these experiments because of the well-established ability of D1 antagonists to block both D1- and D2-mediated unconditioned behaviors. Acute behavioral effects of MK-801 were reduced by SCH 23390 only at doses that decreased basal activity, while the expression of MK-801 sensitization was attenuated by SCH 23390 in some experiments but never completely prevented. Co-administration of SCH 23390 with MK-801 on pretreatment days did not prevent the development of sensitization. In vivo microdialysis experiments compared the effect of MK-801 on extracellular DA levels in the nucleus accumbens (NAc) on Days 1 and 4 of repeated administration. On Day 1, MK-801 produced a modest elevation of DA levels. On Day 4, only 6/17 rats in microdialysis experiments expressed sensitization; these rats, however, exhibited a more rapid rise in DA levels than Day 1 rats or non-sensitized Day 4 rats. Electrophysiological studies revealed that repeated MK-801 administration resulted in supersensitivity of D1 receptors on NAc neurons. Thus, behavioral studies support the importance of non-dopaminergic mechanisms in MK-801 sensitization, while neurochemical and electrophysiological studies suggest that MK-801 sensitization is accompanied by changes in DA transmission in the NAc similar to those observed in amphetamine- or cocaine-sensitized rats.     

Involvement of antioxidant enzymes in multiple-drug resistance in a human T-lymphoblastic leukemia-cell line which over-expresses p-glycoprotein

We have compared the specific activities of Cu/Zn superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in a vinblastine sensitive human T-lymphoblastic cell line (CCRF-CEM) and its multiple drug resistant (MDR) counterpart cell line (CEM/VLB100), which over-expresses P-glycoprotein (PGP). We have found that the specific activity Cu/Zn SOD was consistently 38% increased in CEM/VLB100 cells compared with CCRF-CEM cells. In contrast, the activities of CAT and GSH-Px were similar in the two cell lines. These results suggest that MDR in CEM/VLB100 is a complicated phenotype which not only involves a PGP mechanism, but also a SOD protection mechanism against drug-mediated O2.- cytotoxicity.     

La prothèse à pivot "GSB"

Résumé L'étude porte sur une série de 50 prothèses totales de genou GSB implantées entre 1981 et 1988 au Centre de Traumatologie et d'Orthopédie de Strasbourg. Cette prothèse entre dans la catégorie des prothèses à charnières cimentées, mais son pivot semi rigide diminue efficacement les contraintes exercées sur le ciment. Les résultats sont conformes à ceux retrouvés dans la littérature concernant les prothèses à charnière. L'accent a été mis plus particulièrement sur les complications spécifiques à ce type d'arthroplastie : infections, fractures, complications rotuliennes. Cependant le caractère semi rigide de la GSB a permis la disparition presque totale des descellements qui compliquaient d'ordinaire les prothèses à charnière. La prothèse GSB nous semble donc supérieure aux autres modèles de prothèse à charnière.