Pseudoaneurysm formation after umbilical arterial catheterization: an uncommon but potentially life-threatening complication.

Relatively straightforward placement of an umbilical arterial catheter can be complicated by psuedoaneurysm formation in the presence of a coagulopathy. We describe a case of a neonate, where bedside ultrasound had a key role in the timely diagnosis of this complication and prevented a potentially fatal outcome. Pertinent imaging findings are described with a brief literature review.

Factors that influence the measurement of prostate cancer DNA ploidy and proliferation in paraffin embedded tissue evaluated by flow cytometry.

DNA ploidy and proliferation have been shown in several studies to be prognostic markers for prostate cancer. Flow cytometry (FCM) is often used in the determination of ploidy and proliferation. However, FCM cannot readily distinguish among benign epithelium, stromal and inflammatory cells, high grade prostatic intraepithelial neoplasia (HGPIN), and cancer cells. In this study, we evaluated H&E histologic features of 322 radical prostatectomy formalin-fixed, paraffin-embedded tissue blocks used for determining DNA ploidy, percent S-phase (%S), and %S + %G2M by FCM. The microscopic findings included Gleason score, extent of cancer and HGPIN in the tissue block, and presence of a needle track. The amount of cancer in the block was expressed as a percentage of the total tissue surface area in quartiles: < or =25%, 26-50%, 51-75%, and > or =76%. The extent of HGPIN was recorded in rough 5% intervals. Needle track effect was defined as a combination of fibrohistiocytic reaction, fibrin clot, granuloma formation, and chronic inflammation. The associations between these histologic features and DNA ploidy and proliferation (%S and %S + %G2M) were assessed. In multivariate analyses, Gleason score, the amount of tumor in the tissue block, and the extent of HGPIN were significantly associated with ploidy. Gleason score was the only parameter significantly associated with the proliferation measure of %S. If we included %G2M as part of the proliferative fraction of the histogram, however, both Gleason score and the amount of tumor in the block were significantly associated with this measure of proliferation. The presence of a needle track was not significantly associated with DNA ploidy, %S, or %S + %G2M. In summary, prostate cancer DNA ploidy and proliferation results assessed by FCM in paraffin-embedded tissue blocks were associated with the Gleason score, amount of cancer in the tissue block, and extent of HGPIN. However, the presence of a needle track was not associated with the FCM results.

Effect of inhibition of MAO and COMT on intrarenal dopamine and serotonin and on renal function.

The purpose of the present investigation was to study the effects of inhibition of monoamine oxidase (MAO) and/or catechol-O-methyltransferase (COMT), enzymes involved in the degradation of dopamine (DA) and serotonin (5-HT), on intrarenal DA and 5-HT, as reflected in the renal interstitial fluid (RIF) microdialysate and urine, and on renal function. Inhibition of MAO selectively increased RIF 5-HT from 3.16 +/- 0.38 to 8.03 +/- 1.83 pg/min (n = 7, P < 0.05), concomitant with decreases in mean arterial blood pressure and glomerular filtration rate (2.09 +/- 0. 18 to 1.57 +/- 0.22 ml/min, n = 7, P < 0.05). Inhibition of COMT significantly increased RIF DA (3.47 +/- 0.70 to 8.68 +/- 1.96 pg/min, n = 9, P < 0.05), urinary DA (2.00 +/- 0.16 to 2.76 +/- 0.26 ng/min, n = 9, P < 0.05), and absolute excretion of sodium (6.42 +/- 2.00 to 9.82 +/- 1.62 micromol/min, n = 10, P < 0.05). Combined inhibition of MAO and COMT significantly increased RIF DA, urinary DA, and urinary 5-HT, which was accompanied with increases in urine flow rate, and absolute (3.03 +/- 0.59 to 8.40 +/- 1.61 micromol/min, n = 9, P < 0.01) and fractional excretion of sodium. We conclude that inhibition of MAO selectively increases RIF 5-HT. COMT appears to be more important than MAO in the metabolism of intrarenal DA. Physiological increases in intrarenal DA/5-HT induced by inhibition of their degrading enzymes are accompanied with significant alterations of renal function.

Apparent stimulation of calf thymus DNA polymerase alpha by ATP.

The mechanism by which millimolar concentrations of ATP stimulate the activity and increase the processivity of calf thymus DNA polymerase alpha has been investigated with poly(dA)/oligo(dT) as template/primer to eliminate possible effects due to primer synthesis. The effect of ATP on the rate of DNA synthesis with this template/primer was found to be dependent upon whether or not the ATP was neutralized and the species of buffer used in the reaction. The present studies suggest that ATP stimulation of calf thymus DNA polymerase can be attributed to changes in the pH of the reaction mixture, a shift in the magnesium ion optimum, or both. Furthermore, effects of ATP on the processivity of DNA polymerase alpha could be mimicked by lowering the pH of the reaction mixture.