Mycobacteria and autoimmunity.

Mycobacterial infections can cause a variety of different manifestations. The increasing incidence of these infections worldwide brought another medical dilemma: immunological manifestations characterized by the presence of many autoantibodies and concomitant presence of autoimmune diseases. The burden of tuberculosis reactivation that emerged with immunosuppressive therapy worsened with the growing use of biological disease-modifying antirheumatic drugs (DMARDs). This review will address the relationship between the immune system and mycobacteria.

Percutaneous excimer laser angioplasty of aortocoronary saphenous vein grafts.

Percutaneous coronary excimer laser angioplasty was successfully performed in two patients. An 85 year old woman with a 99% stenosis in a vein graft to a posterior descending artery had the stenosis reduced to 30% with laser angioplasty. Subsequent balloon angioplasty reduced the stenosis further to 20%. A second patient, a man aged 50 years, had multiple previous balloon angioplasties and stent implantation with two subsequent percutaneous atherectomies. Laser angioplasty of the vein graft to the obtuse marginal branch reduced the first of three sequential lesions from 60% to 40%, the second lesion from 90% to none and the third from 60% to 20% without the need for balloon angioplasty. Both procedures were well tolerated without chest pain, burning, vascular perforation or thrombus formation. These cases demonstrate the feasibility of safely performing percutaneous coronary excimer laser angioplasty. Additional studies are indicated to determine the clinical role and potential benefits of this procedure in relation to established procedures and other experimental devices.

Laser ablation of human atherosclerotic plaque without adjacent tissue injury.

Seventy samples of human cadaver atherosclerotic aorta were irradiated in vitro using a 308 nm xenon chloride excimer laser. Energy per pulse, pulse duration and frequency were varied. For comparison, 60 segments were also irradiated with an argon ion and an Nd:YAG (neodymium:yttrium aluminum garnet) laser operated in the continuous mode. Tissue was fixed in formalin, sectioned and examined microscopically. The Nd:YAG and argon ion-irradiated tissue exhibited a central crater with irregular edges and concentric zones of thermal and blast injury. In contrast, the excimer laser-irradiated tissue had narrow deep incisions with minimal or no thermal injury. These preliminary experiments indicate that the excimer laser vaporizes tissue in a manner different from that of the continuous wave Nd:YAG or argon ion laser. The sharp incision margins and minimal damage to adjacent normal tissue suggest that the excimer laser is more desirable for general surgical and intravascular uses than are the conventionally used medical lasers.

Electron microscopy of cell islands in layer II of the primate entorhinal cortex.

An electron microscopic analysis of cell islands in layer II of the entorhinal cortex from rhesus monkeys was made to determine the ultrastructural features of these unique neuronal clusters. The rostral, intermediate, and caudal divisions of the entorhinal cortex were selected for electron microscopic examination. In the rostral division, neurons were grouped together in prominent clusters, often with 10 or more contiguous somata. Somatic and dendrosomatic appositions were frequent, without intervening cellular processes or specialized junctions. Somata were relatively small, typically 10-15 microns in diameter, with oval or circular nuclei that were euchromatic and contained nucleoli. Small nuclear infoldings were commonly seen. A thin shell of perikaryal cytoplasm contained numerous organelles. Axosomatic synapses were infrequent, with a mean of only 1.0 synapse per neuron per thin section. The neuropil contained numerous synapses, and myelinated axons were seen infrequently. In the intermediate division, somatic appositions were rarely observed. Somata were relatively large, typically 15-20 microns in diameter, and displayed a moderate amount of cytoplasm. Axosomatic synapses were relatively common, with a mean of 3.3 synapses per neuron per thin section. In the caudal division, neurons were typically grouped in clusters of two to three contiguous somata. Neurons were about 15 microns in diameter and displayed a moderate amount of cytoplasm. Axosomatic synapses were of moderate frequency, with a mean of 2.5 synapses per neuron per thin section. The neuropil in the caudal division displayed a relatively high frequency of myelinated axons. Our analysis of three regions of the entorhinal cortex revealed significant differences in the frequency of somatic appositions and axosomatic synapses, and in certain ultrastructural features of the somata and neuropil. These results showed that cell islands in layer II of the entorhinal cortex display regional morphologic differences. The paucity of symmetric axosomatic synapses in the rostral division may correlate with this region's vulnerability in certain diseases.

Chronic total obstruction and short-term outcome: the Excimer Laser Coronary Angioplasty Registry experience.

Percutaneous transluminal coronary angioplasty for chronic total obstructions is associated with significantly decreased success rates in comparison with those for dilation of subtotal stenoses. Failure usually results from inability to cross the occlusive lesion with a guidewire, although it may result from inability to pass the balloon catheter after the guidewire has been passed. In the Excimer Laser Coronary Angioplasty Registry, 172 chronic total obstructions were treated in 162 patients (10.3% of the 1,569 patients entered). For chronic total obstructions, passage of a guidewire is a prerequisite for laser angioplasty. Once a guidewire crossed an occlusion, the overall laser success rate for treatment of chronic total obstructions was 83%; the extent of stenosis decreased from 100% to 55 +/- 26%. Success was independent of length of the occlusive lesion. In 74% of patients, adjunctive percutaneous transluminal coronary angioplasty was used after laser angioplasty. A final procedural success, defined as residual stenosis of less than 50% and no major complication (coronary artery bypass grafting, myocardial infarction, or death), was achieved in 90%. Major complications were infrequent; 1.2% of patients required coronary artery bypass grafting, and 1.9% had a Q-wave myocardial infarction. Only one death occurred. The use of laser angioplasty may be of particular value when chronic total obstructions can be crossed with a guidewire but not with a conventional balloon catheter or when the occlusion is confirmed to be extremely long.

A simple method for distal catheter lengthening of ventriculoperitoneal shunts. Technical note.

A simple technique to lengthen the distal catheter of ventriculoperitoneal shunts is described. This method, which utilizes a guidewire, has been successful in elective shunt revisions in eight children.

Pulsed ultraviolet lasers and the potential for safe laser angioplasty.

Endoscopic laser ablation of atheroma using continuous wave lasers is limited by imprecise control of thermal ablation, resulting in a crater that expands in width and depth, with thermal damage to adjacent normal tissue. We compared the gross and histologic effects of pulsed 308 mm excimer irradiation to continuous-wave Nd:YAG and Argon Ion laser irradiation, and pulsed 1,060 nm, 532 nm, 355 nm, and 266 nm laser irradiation in 205 atherosclerotic aortic segments. In contrast to the continuous-wave Nd: YAG, Argon Ion, and pulsed 1,060 nm, 532 nm, and 355 nm laser irradiation, which produced gross and histologic evidence of uncontrolled ablation, the 308 nm and 266 nm pulsed lasers induced incisions that conformed precisely to the beam configuration without gross evidence of thermal injury. The incision edges from these two lasers were histologically smooth and comparable to a scalpel incision. Our histologic findings suggest that rapid, precise endoscopic ablation of vascular and nonvascular tissue can be performed at these shorter pulsed wavelengths with very high precision with relatively little damage or risk to adjacent tissue.

Treatment of refractory coronary occlusions with a new excimer laser catheter: preliminary clinical observations.

BACKGROUND: Total coronary occlusion is a frequent cause of procedural failure after coronary angioplasty, often because of the inability to recanalize the occluded segment with a conventional coronary guidewire. The novel excimer laser catheter described in this report contains a highly efficient, pulsed excimer laser guidewire designed to create a small channel within the occluded coronary segment. A preliminary report of the safety and efficacy of this excimer laser catheter is provided. METHODS: Ten patients with refractory coronary occlusions that could not be crossed by experienced operators using conventional guidewire techniques were treated using a novel laser catheter system. The laser catheter consisted of a densely packed, multiple fiber, helical guidewire measuring 0.020 inches (0.51 mm) in diameter, interfacing a 308 nm excimer laser system and delivering 70-80 mJ/mm2 of energy to the output surface. After the laser guidewire had been advanced to the occlusion site, laser energy was applied to ablate a channel as the wire was advanced through the occlusion. Once the occlusion had been recanalized, standard concentric laser or balloon angioplasty was performed. RESULTS: Complete recanalization was achieved in three total occlusions, and partial recanalization was established in a further three; thus, normal coronary perfusion was attained in six out of 10 patients after adjunct excimer laser or balloon angioplasty. The final minimum lumen diameter averaged 1.51 mm and the final residual stenosis diameter was 27%. In two patients the procedure was unsuccessful but without significant complications; two other patients developed limited coronary perforations without clinical sequelae. CONCLUSION: Refractory coronary occlusions were successfully recanalized in six out of 10 patients using a novel excimer laser catheter. Treatment failures in four patients were not associated with major complications, although limited coronary perforation occurred in two patients.

Usefulness of a fiber optic Swan-Ganz catheter to monitor oxygen transport during volume expansion in a patient with ischemic neurologic deficits from aneurysmal subarachnoid hemorrhage.

The usefulness of a fiber optic Swan-Ganz catheter to monitor oxygen transport during volume expansion in a patient with ischemic neurologic deficits due to aneurysmal subarachnoid hemorrhage is illustrated. Usefulness of oxygen delivery and oxygen consumption measurements are presented. The role of oxygen transport in addition to cardiac hemodynamics and volume status in the management of these neurologic symptoms is emphasized.

Conducción del nacimiento utilización de la cesárea y medicalización del parto en Gran Asunción, Paraguay / Driving birth cesarean sections and the medicalization of birth in Gran Asunción, Paraguay

Introducción: La OMS recomienda que las tasas de cesáreas no superen el 15%, sin embargo en 2008, el 46% de los nacimientos en el Gran Asunción, Paraguay, se produjeron por cesárea. El aumento del uso de cesáreas en zonas de escasos recursos se asocia con mayor morbilidad y mortalidad materna y neonatal, además de los altos costos del cuidado de la salud. Objetivo:El objetivo de este estudio fue comprender el contexto en el que las cesáreas se realizan en Gran Asunción. Métodos: Se recogieron datos cualitativos entre mayo y agosto de 2010, incluyendo treinta entrevistas individuales en profundidad con veinte mujeres quienes habían tenido partos recientes, tanto vaginales como cesáreas, y con diez gineco-obstetras que trabajaban en hospitales públicos de Gran Asunción. Un análisis sistemático de las transcripciones literales identificó varios temas principales, comparando y contrastando los patrones internos y externos de las entrevistas. La alta utilización de cesáreas en el Gran Asunción es el resultado de un proceso medicalizado del parto que no prepara en forma adecuada a las mujeres para el parto vaginal, utiliza intervenciones médicas sin indicación de rutina (por ejemplo ocitocina artificial, episiotomías), y no proporciona apoyo social a las mujeres durante el parto. Resultados: Como resultado, el parto vaginal es a menudo descrito como una experiencia negativa; en consecuencia, muchas mujeres temen al parto vaginal y "ruegan" a los médicos para ser operadas. Algunos médicos también prefieren las cesáreas porque se perciben como más convenientes, controlados y menos riesgosos, para evitar las acusaciones de negligencia. Los modelos de parto medicalizados pueden no satisfacer el componente emocional de la experiencia del parto. Los programas y las políticas que tienen como objetivo mejorar la salud materna deberían considerar la aplicación de un modelo de parto humanizado, ya que puede mejorar la percepción de la atención materna por parte de las mujeres y aumentar el deseo de buscar atención prenatal y tener partos vaginales. Palabras claves: cesáreas, parto humanizado, parto medicalizado, educación para el parto, Gran Asunción.

Introduction; WHO recommends that cesarean rates not exceed 15%; however in 2008, 46% of births in Gran Asunción, Paraguay occurred by cesarean. The increased use of cesareans in resource-poor settings is associated with increased maternal and neonatal morbidity and mortality and high healthcare costs. The objective of this study was to understand the context in which cesareans occur in Gran Asunción. Methods: Qualitative data were collected between may and august 2010, including thirty in-depth individual interviews, twenty with recently postpartum women who had vaginal or cesarean births and ten with obstetrician-gynecologists who worked at public hospitals in Gran Asunción. A systematic analysis of verbatim transcripts identified major themes, comparing and contrasting patterns within and between interviews. The high utilization of cesareans in Gran Asunción results from a medicalized birth process that poorly prepares women for vaginal birth, routinely utilizes medical interventions without indication (e.g. artificial oxytocin, episiotomies), and does not provide social support to women during labor. Results: As a result, vaginal birth is often portrayed as a negative experience; many women consequently fear vaginal birth and "beg" doctors to operate. Some doctors also prefer cesareans because they are perceived as more convenient, controllable, and less risky for accusations of malpractice. Medicalized birth models may fail to address the emotional quality of the birth experience. Programs and policies that aim to improve maternal health should consider applying a humanized birth model because it may improve women's perceptions of maternal care and increase desires for seeking maternal care and vaginal births. Keywords: Cesareans, humanized birth, medicalized birth, childbirth education, Gran Asunción.

Excimer laser coronary angioplasty: American multicenter experience.

Second generation angioplasty devices remove rather than displace atherosclerotic plaque. For such devices to be useful they must be capable of addressing the major problems not solved by balloon catheters: difficult anatomy, abrupt reclosure, and restenosis. Laser angioplasty systems have proven difficult to adapt to treatment of coronary artery disease, because of heat generation, problems with perforation, and inflexibility of optical fibers. The AIS excimer laser coronary angioplasty system couples a 308 nm pulsed excimer laser to multifiber over-the-wire catheters of 1.3 mm, 1.6 mm, and 2.0 mm diameters. The laser's uniquely long pulse width (250 ns) allows delivery of higher energies through smaller fibers. Because the catheter system is front firing, risk of perforation is reduced. The Excimer Laser Coronary Angioplasty Registry involves six institutions investigating the AIS excimer system. This report deals with 255 lesions in the first 210 patients in the registry. The study cohort resembles a standard angioplasty population in terms of demographics, symptomatology, vessels dilated, and complications. Unlike a standard PTCA cohort, the ELCA patients had a higher prevalence of chronic total occlusions, calcified lesions, long lesions and diffuse disease. Both very distal lesions and those that had previously failed PTCA were successfully treated with ELCA. The laser was successful in 85% of cases, but adjunctive balloon angioplasty was required in the majority. There were no instances of perforation.

Pulsed laser angioplasty: wavelength power and energy dependencies relevant to clinical application.

Despite the theoretical advantages of submicrosecond pulsing for clinical laser angioplasty systems, the optimal laser parameters for clinical application are undefined. Further, the enormous peak powers achieved by submicrosecond pulses destroy available fiberoptics. We irradiated 797 segments of cadaver atherosclerotic aorta with nanosecond pulses at 266, 308, 355, 532, and 1064 nanometers. Effective cutting occurred at lower energy fluences in the ultraviolet than in the visible or infrared. For 308 nanometers, at any energy density, number of pulses to perforation was relatively independent of power density. Therefore, long-pulse ultraviolet wavelengths which could be transmitted through fiberoptics were identified as well suited for a clinical, submicrosecond pulsed laser angioplasty system.

Percutaneous excimer laser coronary angioplasty of lesions not ideal for balloon angioplasty.

BACKGROUND: Excimer laser coronary angioplasty is a new, investigational technique for treating coronary artery stenoses. Initial reports have demonstrated acute efficacy and relative safety of this procedure, but have not addressed the effect of lesion type on acute success and complication rates. METHODS AND RESULTS: In the first 100 patients undergoing percutaneous excimer laser coronary angioplasty at our institution, acute laser success was obtained in 84% and procedural success was obtained in 94%. There were six acute closures during laser angioplasty and one myocardial infarction. Two patients required emergency coronary bypass surgery. Sixty-five percent of patients had lesions not ideal for balloon angioplasty because of lesion morphology (tubular, diffuse, or chronic total occlusion) or ostial location. There were 10 tubular stenoses, 29 diffuse lesions, 18 chronic total occlusions, and eight ostial lesions, including five aorto-ostial lesions. In this nonideal subgroup, the acute success rate with laser was 86% (72% of chronic total occlusions and 91% of non-totally occluded lesions), and the procedural success rate was 94%. There were three acute occlusions during laser angioplasty but no myocardial infarctions, emergency bypass surgeries, or deaths. One coronary artery perforation occurred without clinical sequelae. Laser angioplasty was successful in four of six lesions (67%) in which balloon angioplasty had failed. Laser success was obtained in 10 of 11 (91%) moderately or heavily calcified stenoses. Eight eccentric lesions and two lesions on bends were successfully treated without dissection or perforation. No side branch occlusions occurred in the 15 patients in whom one or more major branches originated within the lesion treated. Adjunctive balloon angioplasty was performed in 47% of cases, usually to obtain a larger final luminal diameter. Need for adjunctive balloon angioplasty decreased to 36% after a larger (2.0 mm) laser catheter became available. Twenty-eight percent of the 105 lesions treated were American College of Cardiology/American Heart Association classification type A, 47% were type B, and 25% were type C. Laser and procedural successes were obtained in 83% and 97% of type A, 88% and 96% of type B, and 85% and 88% of type C lesions, respectively. CONCLUSIONS: In our initial experience, excimer laser angioplasty was found to be acutely effective and safe therapy for lesions identified as not ideal for balloon angioplasty. This technique may provide a useful adjunct or alternative to balloon angioplasty in selected patients.

Interventional cardiovascular therapy by laser and thermal angioplasty.

The advent of balloon angioplasty as a clinical device crystallized the concept of nonsurgical revascularization. The problems of restenosis, diffuse disease, and total occlusions persist despite the demonstrated efficacy of balloon angioplasty. During the past 5 years, a variety of laser devices and catheter designs have demonstrated usefulness in the treatment of peripheral vascular disease. Initial success rates of 70-90% have been reported in occluded femoropopliteal arteries. Further clinical trials are warranted to compare the relative efficacy of these devices with each other and conventional therapies. Thermal ablative devices have not yet shown great promise for treatment of coronary disease. Modified versions of these devices as well as nonthermally acting excimer lasers are promising as clinical tools for enhancing our ability to nonsurgically revascularize patients, and trials with these devices are now underway.

Morphological predictors of acute complications after percutaneous excimer laser coronary angioplasty. Results of a comprehensive angiographic analysis: importance of the eccentricity index.

BACKGROUND: Percutaneous excimer laser coronary angioplasty (ELCA) is a new technique for recanalization of arteries obstructed by coronary atherosclerosis. This study was conducted to assess the complication rate and determine the influence of clinical and angiographic characteristics on complications after ELCA. METHODS AND RESULTS: A detailed, quantitative, angiographic core laboratory analysis of patients undergoing ELCA was performed by two experienced angiographers who were not the primary laser angioplasty operators. Two hundred patients underwent 203 separate procedures on 220 lesions at three medical centers. Laser success was achieved in 180 lesions (81.8%) and procedural success in 199 (90.5%). Emergency coronary artery bypass graft (CABG) was required in five patients (2.5%). One patient suffered a Q wave myocardial infarction; there were no deaths. Also, acute closure and perforation occurred in 10 (4.5%) and three (1.4%) vessels, respectively. Coronary dissections after laser treatment were seen in 36 vessels (16.4%). Multivariate analysis found two independent preprocedural factors related to complications: eccentricity index, which is the percent deviation of the lesion lumen from the center of the artery (p = 0.0007), and proximal vessel diameter (p = 0.033). In addition, an abrupt proximal face of the lesion was associated with angiographic complications by univariate analysis (p = 0.051). Multivariate analysis showed the eccentricity index (p = 0.032) to be the only independent predictor for the occurrence of any one or more of the important complications (emergency CABG, perforation, acute closure, or Q wave myocardial infarction), whereas lesion angle greater than 45 degrees was a significant univariate predictor (p = 0.029). Other predictors of complications with balloon percutaneous transluminal coronary angioplasty, such as increased lesion length, rough edges, calcification, ulceration, and branch point, were not predictive of complications with the excimer laser. CONCLUSIONS: The degree of lesion eccentricity is the most powerful predictor of complications after ELCA. This and other morphological predictors may be of benefit in the selection of patients for ELCA as well as directing future development of this new technology.

Excimer laser coronary angioplasty of aorto-ostial stenoses. Results of the excimer laser coronary angioplasty (ELCA) registry in the first 200 patients.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) of aorto-ostial stenosis has been associated with a lower rate of acute success, a high risk of vessel closure, and late restenosis. The purpose of this report is to document a prospective multicenter trial of excimer laser coronary angioplasty (ELCA) of aorto-ostial stenosis involving the coronary arteries and saphenous vein grafts. METHODS AND RESULTS: Between December 1989 and May 1992, 206 aorto-ostial ELCA procedures were performed on 209 stenoses in 200 patients. Canadian Cardiovascular Society class III or IV angina was present in 76%. The distribution of stenosis locations was left main coronary (LM) in 26 (12%), right coronary (RCA) in 124 (59%), and vein grafts (VG) in 59 (28%). Adjunctive PTCA was performed in 72%. Procedure success defined as < or = 50% diameter stenosis without major complications was achieved in 90% (LM, 92%; RCA, 89%, VG, 90%). Quantitative angiographic analysis documented an improvement in stenosis diameter from 0.8 +/- 0.5 mm or 76 +/- 14% at baseline to 2.1 +/- 0.6 mm or 36 +/- 15% at completion (P < .01). The majority of the acute gain in diameter (1.0 +/- 0.6 mm) resulted from ELCA. A major complication during hospitalization occurred in 3.9% (death, 0%; Q-wave myocardial infarction, 0.5%; bypass surgery, 3.4%). The only logistic regression univariate and multivariate predictor of procedure failure was female gender. Six-month angiographic follow-up, available in 51% of eligible patients, documented an average lumen diameter of 1.7 +/- 1.0 mm and mean diameter stenosis of 46 +/- 26%. Restenosis (> 50% diameter stenosis) occurred in 39% (LM, 64%; RCA, 35%; VG, 35%). Restenosis was less likely when residual stenosis was < or = 35% (28% versus 53%, P < .05). Clinical events at follow-up were death, 2.7%; bypass surgery, 6.5%; myocardial infarction, 2.2%; and repeat angioplasty, 16.2%. Of the remainder, 78% were asymptomatic, class I or II for anginal symptoms. An adverse event during follow-up was more than twice as likely in the group with LM (50.0% versus 21.1%, P < .02). CONCLUSIONS: ELCA is acutely effective and safe therapy in patients with aorto-ostial stenosis. Six-month restenosis, adverse-event rates were higher and functional status was poorer in the group with LM stenosis. ELCA may be considered as an alternative to bypass surgery in carefully selected patients with isolated aorto-ostial stenosis of the RCA and saphenous vein grafts.

Percutaneous excimer-laser and excimer-laser-assisted angioplasty of the lower extremities: results of initial clinical trial.

Percutaneous peripheral excimer-laser angioplasty at 308 nm was used for treatment of 30 patients with peripheral vascular disease. Twenty-eight patients underwent laser-assisted balloon angioplasty, and two patients underwent laser angioplasty alone. Acute angiographic and clinical success was achieved in 24 of 31 (77%) femoropopliteal stenoses and occlusions. Seven of nine (78%) stenoses, six of seven (86%) short (0-5 cm) occlusions, seven of eight (88%) medium-length (6-10 cm) occlusions, three of four (75%) long (11-15 cm) occlusions, and one of three (33%) extreme (greater than 15 cm) occlusions were successfully treated. Inability to treat total occlusions was in each case related to a failure to maintain coaxial position and subintimal passage of the fiber. These cases demonstrate the feasibility of safely performing percutaneous peripheral excimer-laser or excimer-laser-assisted angioplasty. The overall frequency of restenosis after a mean follow-up period of 9.1 months was 29%. The data suggest that these procedures may be useful for the treatment of peripheral vascular disease in selected patients.