Plasmodium-falciparum-infected erythrocytes adhere to immortalized human bone marrow endothelial cells

Two cases of recurrent pancreatitis, due to duodenal duplication, are reported. The aim of this paper is to emphasise the role of endoscopic retrograde cholangiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) in the detection of associated pancreaticobiliary anomalies and in the planning of the correct surgical approach. The order of imaging in a child with recurrent pancreatitis should be US, barium meal and PTC. ERCP is often difficult to perform in children.     

A yeast glutamine tRNA signals nitrogen status for regulation of dimorphic growth and sporulation

Dimorphic growth of the budding yeast Saccharomyces cerevisiae is regulated by the quality of the nitrogen supply. On a preferred nitrogen source diploid cells grow as ellipsoidal cells by using a bipolar pattern of budding, whereas on a poor nitrogen source a unipolar pattern of budding is adopted, resulting in extended pseudohyphal chains of filamentous cells. Here we report that the quality of the nitrogen source is signaled by the glutamine tRNA isoform with a 5'-CUG anticodon (tRNACUG). Mutations that alter this tRNA impair assessment of the nitrogen supply without measurably affecting protein synthesis, so that mutant cells display pseudohyphal growth even on a preferred nitrogen source. The nitrogen status for other nitrogen-responsive processes such as catabolic gene expression and sporulation also is signaled by this tRNA: mutant cells inappropriately induce the nitrogen-repressed gene CAR1 and undergo precocious sporulation in nitrogen-rich media. Therefore, in addition to its role in mRNA translation, this tRNA also transduces nitrogen signals that regulate development.     

Determination of the antitumor agent depsipeptide in plasma by liquid chromatography on serial octadecyl stationary phases

We have cloned the rat fibroblast growth factor-2 (FGF-2) promoter region including 1058 base pairs (bp) of 5'-flanking DNA. Complete sequencing of this promoter region revealed a 74 bp domain between nucleotides-793 and-720 that was greater than 97% A/G-rich. A repeat of the sequence 5'-AGGGAGGG-3' separated by 11 bp was located at the core of this domain. A 37 bp A/G-rich oligonucleotide containing these AGGG-repeat sequences was synthesised, and tested for function on a minimal herpes simplex virus thymidine kinase (TK) promoter, fused to the firefly luciferase gene (TKp.luc), in transiently transfected neonatal rat cardiac myocytes. Promoter activity was stimulated approximately 3 fold in the presence of AGGG-repeat sequences. This effect was neither tissue or species-specific since TK promoter activity was increased approximately 11 fold in both rat and human glial tumor cells. Four specific complexes (Cl-4) were detected between neonatal rat heart nuclear proteins and the 37 bp A/G-rich oligonucleotide by gel mobility shift assay. Competition with excess unlabelled 37 bp A/G-rich oligonucleotide revealed that two complexes represented very high affinity/specificity interactions (C2 > C4) while Cl and C3 were of lower affinity. As a result, competition with up to a 25 fold molar excess of 37 bp A/G-rich oligonucleotide led to the loss of C2 and C4, and a corresponding and transient increase in the levels of Cl and C3, which themselves were reduced with more competitor oligonucleotide. The AGGG-repeat resembles the 5'-gGGGAGGG-3' sequence previously implicated in the response of the atrial natriuretic factor promoter to the alpha-adrenergic agonist, phenylephrine. Although an additional 1.5 fold increase in TK promoter activity was detected in the presence of the 37 bp A/G-rich oligonucleotide with phenylephrine treatment of transfected myocytes, this effect was not statistically significant. Furthermore, there was no difference in the gel mobility shift (Cl-4) pattern obtained with the 37 bp A/G-rich oligonucleotide and nuclear protein isolated from neonatal rat cardiac myocytes grown in the presence or absence of norepinephrine. These data suggest that the A/G rich sequences in the rat FGF-2 gene 5'-flanking DNA, including the AGGG-repeat, are able to confer stimulatory activity on a promoter in a tissue- and species-independent manner, but alone are not able to induce a significant phenylephrine response in neonatal rat cardiac myocytes.     

Sources and timing of anthropogenic pollution in the Ensenada de San Simon (inner Ria de Vigo), Galicia, NW Spain: an application of mixture-modelling and nonlinear optimization to recent sedimentation

The Ensenada de San Simon is the inner part of the Ria de Vigo, one of the major mesotidal rias of the Galician coast, NW Spain. The geochemistry of its bottom sediments can be accounted for in terms of both natural and anthropogenic sources. Mixture-modelling enables much of the Cr, Ni, V, Cu, Pb and Zn concentrations of the bottom and subaqueous sediments to be explained by sediment input from the river systems and faecal matter from manmade mussel rafts. The compositions and relative contributions of additional, unknown, sources of anomalous heavy-metal concentrations are quantified using constrained nonlinear optimization. The pattern of metal enrichment is attributed to: material carried in solution and suspension in marine water entering the Ensenada from the polluted industrial areas of the adjacent Ria de Vigo; wind-borne urban dusts and/or vehicular emissions from the surrounding network of roads and a motorway road-bridge over the Estrecho de Rande; industrial and agricultural pollution from the R. Redondela; and waste from a former ceramics factory near the mouth of the combined R. Oitaben and R. Verdugo. Using (137)Cs dating, it is suggested that heavy metal build-up in the sediments since the late 1970s followed development of inshore fisheries and introduction of the mussel rafts (ca. 1960) and increasing industrialisation.     

Solid-phase extraction of technetium--amine complexes onto C18 silica and its application to the isolation of 99Tc

The extraction of Tc-tripentylamine complexes onto C18 silica solid-phase extraction columns is evaluated for the selective removal of 99Tc from other isotopes. The Tc-amine complex is quantitatively extracted from sulfuric acid and can be recovered from the column by elution with dilute alkali. A clean separation of Tc from all likely contaminants, including Ru, is achieved showing that C18 silica solid-phase extraction columns are a viable and attractive alternative to the solvent extraction of 99Tc.     

Montgomery Lecture, 1975. Changing concepts of the prognosis and management of small malignant melanomas of the choroid

Recent studies have shown conclusively that patients with small choroidal melanomas tend to have a favourable prognosis and that this, in turn, is closely related to tumour cell type, mitotic activity, degree of trans-scleral extension, and other characteristics of the tumour. It has not yet been established whether enucleation of the tumour-containing eye increases or decreases the patient's chance for survival. The frequency with which we observe late metastatic deaths among patients who had seemingly been 'cured' by enucleation indicate that host factors are most important in determining whether or not a patient will succumb to his tumour. It is possible that nonsurgical methods of treatment may be as effective or even more effective than enucleation (a) by diminishing the changes of intravasation of tumour cells, and (b) by promoting a more favourable host response to the tumour. While the total experience in management by methods other than enucleation is small, the results reported to date with photocoagulation, radiation, and no therapy are encouraging. Only after a much larger experience with prolonged periods of evaluation (more than 10 years after recognition of the tumour) will we be able to compare the results with those obtained by enucleation.     

Comparative vasodilator effects of nitroglycerin, pentaerythritol trinitrate and biometabolites, and other organic nitrates

Previous studies in man have shown pentaerythritol (PE) trinitrate, given either sublingually or orally, produces a prolonged hypotensive effect. The coronary vasodilator and systemic vasodepressor activities of PE trinitrate and its metabolites, PE dinitrate, PE mononitrate and PE, were evaluated in dogs to determine whether the metabolites were active and contributory. Coronary vasodilator activity was estimated with a flow transducer placed on the left anterior descending artery, and reduction of arterial pressure was determined directly via the femoral artery. Quantitative comparisons were made from dose-response curves established for nitroglycerin (ng), PE nitrates, and other common organic nitrates after intrajugular administration. Increase of coronary blood flow and reduction of arterial pressure were proportionally related, and the proportionality was the same for all drugs. Relative to NG, the potency of PE trinitrate was about 20 percent, erythrityl tetranitrate 12 percent, and isosorbide dinitrate 3.5 percent. The ratios of vasodilator activity of PE trinitrate and its metabolities were: PE trinitrate 100; PE dinitrate 1.5; PE mononitrate 0.5; and PE O. Tachyphylaxis was observed after close-order injections of NG or PE trinitrate. In addition, there was cross tolerance between NG and PE trinitrate and also between PE trinitrate and its less active metabolites.     

Therapeutic equivalency of two lidocaine preparations

Twenty-five volunteers were studied as to the onset and duration of action of two commercial brands of lidocaine. One and two percent concentrations of the preparations were tested intradermally using a double-blind, cross-over protocol. Both needle-drop and electrical stimulation techniques were employed as the source of pain stimulus. Five additional subjects were studied in a dose-ranging study using a placebo and lidocaine concentrations of 0.25%, 0.50%, 0.75% and 1.0%; this experiment was conduced to determine the sensitivity of the experimental methods. Both the needle-drop and electrical stimulation techniques were able to distinguish the 0.25% preparation from placebo and from the other concentrations of 1% and 2%. The two preparations were found to be statistically equivalent at concentrations of 1% and 2% and could be used interchangeably in clinical procedures.