Recognition and management of catheter-induced pulmonary artery rupture

The use of PCR to amplify a specific virA gene fragment serves as a highly specific and sensitive method to detect virulent bacteria of the genus Shigella and enteroinvasive Escherichia coli. Amplification of a 215-bp DNA band was obtained by using isolated genomic DNA of Shigella, individual cells of Shigella dysenteriae, and mayonnaise contaminated with S. dysenteriae. Moreover, a multiplex PCR with specific (virA) and bacterium-restricted (16S ribosomal DNA) primers generated an amplification product of approximately 755 bp for all bacteria tested and an additional 215-bp product for Shigella and enteroinvasive E. coli.     

Narrow complex tachycardia with VA block: diagnostic and therapeutic implications

To review our experience with cases of narrow complex tachycardia with VA block, highlighting the difficulties in the differential diagnosis, and the therapeutic implications. Prior reports of patients with narrow complex tachycardia with VA block consist of isolated case reports. The differential diagnosis of this disorder includes: automatic junctional tachycardia, AV nodal reentry with final upper common pathway block, concealed nodofascicular (ventricular) pathway, and intra-Hissian reentry. Between June 1994 and January 1996, six patients with narrow complex tachycardia with episodes of ventriculoatrial block were referred for evaluation. All six patients underwent attempted radiofrequency ablation of the putative arrhythmic site. Three of six patients had evidence suggestive of a nodofascicular tract. Intermittent antegrade conduction over a left-sided nodofascicular tract was present in two patients and the diagnosis of a concealed nodofascicular was made in the third patient after ruling out other tachycardia mechanisms. Two patients had automatic junctional tachycardia, and one patient had atrioventricular nodal reentry with proximal common pathway block. Attempted ablation in the posterior and mid-septum was unsuccessful in patients with nodofascicular tachycardia. In contrast, those with atrioventricular nodal reentry and automatic junctional tachycardia readily responded to ablation. The presence of a nodofascicular tachycardia should be suspected if: (1) intermittent antegrade preexcitation is recorded, (2) the tachycardia can be initiated with a single atrial premature producing two ventricular complexes, and (3) a single ventricular extrastimulus initiates SVT without a retrograde His deflection. The presence of a nodofascicular pathway is common in patients with narrow complex tachycardia and VA block. Unlike AV nodal reentry and automatic junctional tachycardia, the response to ablation is poor.     

The detection and documentation of trace wound patterns by use of an alternative light source

This article is a discussion of the use of narrow-band light sources coupled with cameras equipped with band-pass filters to document patterned injuries on human skin. Several case reports are included.     

Promotion of healthy lifestyle: knowledge and attitudes of primary care physicians

Preretinal neovascularization and chronic retinal oedema are the two major sight-threatening complications that can occur during diabetic retinopathy. Ocular neovascularization is strongly associated with retinal ischaemia, and growth factors have been implicated in its pathogenesis. The ischaemic retina is assumed to secrete growth factors that stimulate residual vessels to proliferate. Interest has focused on basic fibroblast growth factor (bFGF), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF beta) and more recently vascular endothelial cell growth factor (VEGF). Histologic studies have demonstrated the presence of growth factor proteins and receptors and/or their mRNA, mainly VEGF, PDGF, and bFGF, in preretinal membranes of patients with proliferative diabetic retinopathy. Elevated intravitreal levels of IGF-1 and VEGF correlating with neovascular activity have been found in some patients. However, a direct causal relationship between ischaemia, growth factors and neovascularization has not been clearly demonstrated despite considerable research work. To date, the growth factor correlating most closely with neovascularization is VEGF. As many growth factors seem to be produced during the neovascular process, their specific inhibition probably will have limited effects. Laser photocoagulation of the retina has proved beneficial for regression of new vessels, probably through destruction of the ischaemic retina producing neovascular growth factors, and is currently the only treatment for proliferative diabetic retinopathy. Inhibition of IGF-1 by somatostatin analogs has produced unsatisfactory results. Other vascular inhibitors are currently being studied.     

Desensitizing GABAC receptors on carp retinal bipolar cells

Bicuculline- and baclofen-insensitive GABA receptors (GABAC receptors) on bipolar cells acutely dissociated from carp retina were investigated with using the whole-cell patch-clamp recording technique. The currents of these cells mediated by GABAC receptors showed striking desensitization, even at low concentrations of GABA. Both the time constant tau of the GABAC current decay and the extent of desensitization were significantly different from that of GABAC receptors previously observed in other retinas and elsewhere in the CNS, suggesting that the GABAC receptors of carp bipolar cells might be distinct in intracellular mechanisms and subunit composition.     

A family of gram-negative bacterial outer membrane factors that function in the export of proteins, carbohydrates, drugs and heavy metals from gram-negative bacteria

Differentiation of biliary epithelial cells from hepatic endodermal cells of the mouse embryo was examined with a special attention to the role of the connective tissue. When the whole liver primordium of the 9.5-day mouse embryo was cultured in vitro for 5 days, the endodermal cells differentiated into mature hepatocytes expressing carbamoylphosphate synthetase I (CPSI) and accumulating glycogen. Intrahepatic bile duct cells and connective tissue were poorly developed in this culture. However, when the hepatic endoderm was recombined with the 4-day embryonic chick lung mesenchyme and cultured in vitro, the endodermal cells differentiated into many ductal epithelial cells as well as mature hepatocytes with abundant connective tissue development. These results suggest that the ducts might be bile ducts, and that connective tissue is very important for bile duct development. In addition, this in vitro culture system might be useful for the study of mechanisms of bile duct differentiation and congenital biliary atresia.     

Histology of rat small bowel transplants: cyclosporine A ameliorates features of rejection including apoptosis and ganglion cell reduction

The spectrum of photoaging in human skin shows a recognizable progression from subtle to profound, reflecting the various anatomic and structural changes that appear with aging skin. Qualification and quantification of these changes on both the macroscopic and microscopic levels enable the physician to select and evaluate appropriate therapeutic approaches to the problem of chronic solar damage. Comparative studies remain to be done that will further refine our abilities to match the right solutions to the recognized problems.