Coronary computed tomography angiography for the evaluation of patients with acute chest pain.

Acute chest pain is a common presenting complaint of patients attending emergency room departments. Despite this, it can often be challenging to completely exclude a diagnosis of acute coronary syndrome following an initial standard clinical and biochemical evaluation. As a result of this, patients are often admitted to hospital until the treating clinician is satisfied that this diagnosis can be excluded. This process imparts a significant health economic burden by not only increasing hospital bed occupancy rates but also by the unnecessary layering of diagnostic investigations. With the rapid advances in coronary computed tomography angiography (CTA), there has been considerable interest in whether coronary CTA may be a viable alternative to this current standard care. We review the current literature and supporting evidence for utilising coronary CTA in the evaluation of patients presenting with acute chest pain in terms of its diagnostic accuracy, safety, cost-effectiveness and prognostic implications.

Antimycobacterial activity of lichen substances.

We describe here the extraction and identification of several classes of phenolic compounds from the lichens Parmotrema dilatatum (Vain.) Hale, Parmotrema tinctorum (Nyl.) Hale, Pseudoparmelia sphaerospora (Nyl.) Hale and Usnea subcavata (Motyka) and determined their anti-tubercular activity. The depsides (atranorin, diffractaic and lecanoric acids), depsidones (protocetraric, salazinic, hypostictic and norstictic acids), xanthones (lichexanthone and secalonic acid), and usnic acid, as well seven orsellinic acid esters, five salazinic acid 8',9'-O-alkyl derivatives and four lichexanthone derivatives, were evaluated for their activity against Mycobacterium tuberculosis. Diffractaic acid was the most active compound (MIC value 15.6mug/ml, 41.6 microM), followed by norstictic acid (MIC value 62.5 microg/ml, 168 microM) and usnic acid (MIC value 62.5 microg/ml, 182 microM). Hypostictic acid (MIC value 94.0 microg/ml, 251 microM) and protocetraric acid (MIC value 125 microg/ml, 334 microM) showed moderate inhibitory activity. The other compounds showed lower inhibitory activity on the growth of M. tuberculosis, varying from MIC values of 250 to 1370 microM.

Antibacterial activity and phytochemical analysis of Vochysia divergens (Vochysiaceae).

Vochysia divergens Pohl (Vochysiaceae) is a tree commonly found in wet soils of 'Pantanal' of Mato Grosso, Brazil, and used in folk medicine against infections and asthma. We have studied different extracts and some isolated compounds from this plant for antibacterial activity. From the extracts of the stem bark beta-sitosterol, betulinic acid and sericic acid were isolated. The minimal inhibitory concentration (MIC) for Staphylococcus aureus were: ethanolic extract (MIC = 1.5 mg/ml); ethyl acetate extract (MIC = 2.0 mg/ml); and sericic acid (MIC = 1.0 mg/ml). Escherichia coli was resistant until 5 mg/ml.

The relaxant action of jatrophone in rat portal vein. A comparison with protein kinase C inhibitors.

Jatrophone, staurosporine and H-7, caused graded inhibition of rat portal vein contractions induced by phorbol 12-myristate 13-acetate (PMA), noradrenaline, endothelin-1 or KCl, with IC50s of 86 nM, 13 microM, 11 microM and 9 microM, respectively. Jatrophone was equipotent to H-7, but 100 to 500 fold less potent than staurosporine. Jatrophone, H-7 and staurosporine, also dose-dependently inhibited rhythmic contractions of the rat portal-mesenteric vein with IC50s of 15 microM, 9 microM and 75 nM, respectively. Jatrophone, H-7 and staurosporine caused graded relaxations of preparations contracted with endothelin-1 or PMA with IC50s of 12 and > 1000 microM, 8 and 13 microM and 7 and 12 nM, respectively. All three compounds caused graded inhibition of caffeine-induced contractions in Ca(2+)-free solution containing EGTA. The similarity between the vasorelaxant actions of jatrophone, staurosporine and H-7 in rat portal vein suggests that jatrophone acts, at least in part, through inhibition of PKC-dependent mechanisms. Moreover, like the PKC inhibitors, its vasorelaxant action may also involve other mechanisms unrelated to protein kinase C inhibition.

Action of pregnane compounds from Mandevilla illustris against contractions induced by kinins and other oxytocics in the rat isolated uterus.

1. The effects of 5 pregnane compounds isolated from the rhizomes of Mandevilla illustris were examined against bradykinin (BK), Lysyl-bradykinin (L-BK), acetylcholine (ACh) and oxytocin (Ot)-induced contractions in the isolated uteri of the rat. 2. Compounds MI 15 and MI 18 (5-40 micrograms/ml) caused a parallel and concentration-dependent rightward displacement of BK and L-BK concentration-response curves. Compound MI 21 (2.5-10 micrograms/ml) also produced a concentration-dependent displacement to the right of the BK concentration-response curve, but reduced its maximal response. Schild analysis of these data were linear (r close to 1) and furnished the following PA2 values (as G/ml): 6.0, 5.1 and 5.9, respectively. However, the slopes were significantly higher than unity. Compounds MI 25 and MI 27 (10-40 micrograms/ml) caused little or even no effect against BK and ACh responses. 3. In addition, compounds MI 18 and MI 21 (10-40 micrograms/ml) also antagonized in a concentration-dependent manner L-BK concentration-response curves. Schild plot were linear (r close to 1) and yielded the nominal pA2 values (as G/ml) of 5.0 and 5.8, respectively, but the slopes were significantly different from one. 4. Like the results obtained previously with the crude extract from M. illustris, the purified compounds from the rhizome of this plant were not selective towards kinin action since at the same range concentrations they markedly interfered with both the sensitivities and the maximal responses caused by ACh and Ot in this preparation.