Effects of lung volume reduction surgery for emphysema on diaphragm dimensions and configuration.

Part of the functional benefit provided by lung volume reduction surgery (LVRS) may be related to improvement in respiratory muscle function resulting from changes in diaphragm dimension and configuration. To study these changes, we obtained 3D reconstructions of the muscle using spiral computed tomography in 11 patients with severe emphysema before and 3 mo after surgery, and in 11 normal subjects matched for sex, age, height, and weight. Bilateral LVRS was performed by thoracoscopy in eight patients and by sternotomy in three patients. Acquisitions were made in the supine posture at relaxed FRC, midinspiratory capacity, and TLC. On average, LVRS produced a 51 +/- 11% increase in FEV(1) and a 30 +/- 4% decrease in FRC. The total surface area of the diaphragm (A(di)) and of the zone of apposition (A(ap)) at FRC increased by 17 +/- 4% and 43 +/- 8%, respectively, but the surface area of the dome did not change. Compared with the values recorded in the normal subjects, postoperative values of A(di) and A(ap) at FRC were reduced by 11% (p < 0.05) and 24% (p < 0.005), respectively. The curvature of the dome increased at TLC in the left sagittal plane, but was otherwise unaffected by the procedure. We conclude that LVRS substantially increases A(di) and A(ap), but does not significantly improve diaphragm configuration at FRC.

Continuous telemetry from a chronic canine model of sudden cardiac death.

INTRODUCTION: We sought to develop a continuously telemetered animal model of sudden cardiac death (SCD) to study the role of existing infarcts and acute ischemia in fatal arrhythmias. METHODS AND RESULTS: A telemetry system capable of recording eight channels of electrophysiologic data continuously and chronically has been developed. To demonstrate the use of this technology in an animal model of sudden death, 12 anesthetized dogs were instrumented with eight electrodes located in endocardium of the right side of the heart, epicardium of the left ventricle (LV), or in the subcutaneous tissues. The left anterior descending (LAD) coronary artery was occluded for 90 minutes and reperfused to produce LV infarction. A copper wire was placed in the left circumflex (LCX) coronary artery to cause intimal injury in a second arterial bed. The telemetry unit recorded deaths in seven animals between 19 to 64 hours after surgery. Five animals that did not experience SCD by the fifth postoperative day served as controls. There were three modes of SCD: complex ventricular ectopy that degenerated into ventricular fibrillation (VF, n = 4); normal sinus rhythm that suddenly degenerated into VF (n = 1); and bradycardia (RR intervals >1,000 msec) that lasted >3 minutes and preceded VF (n = 2). ST segment changes were significantly greater in the LCX-bed electrograms for tachyarrhythmic compared to bradyarrhythmic deaths (mean +/- SD; 4.0 +/- 3.4 mV and 0.2 +/- 0.8 mV, respectively). Fast Fourier transform showed the peak frequency of VF 10 seconds after onset was significantly higher in the five dogs with initial tachyarrhythmias compared with the VF that followed profound bradycardia (6.5 +/- 3.1 Hz and 3.7 +/- 0.6 Hz, respectively). Computer-assisted planimetry of postmortem heart slices revealed that infarcts in the two dogs with bradycardic events were larger (19.7% +/- 2.2% of the LV and septal mass) than in the five dogs with tachyarrhythmias (7.7% +/- 2.4%) or in the five control dogs (11.9% +/- 8.1%). CONCLUSION: It is possible to record via telemetry the events leading to SCD in an animal model. Continuous telemetry monitoring demonstrated that both tachyarrhythmias and bradyarrhythmias ultimately resulted in VF in an animal model of SCD. Animals with tachyarrhythmic deaths had greate ischemia in the LCX bed, smaller preexisting infarcts, and higher VF peak frequency than animals with bradyarrhythmic deaths.

[Alpha 1-antiproteinase deficiency]. / Alpha-1-Antiproteinase-Mangel.

The dysbalance between proteolytic neutrophil elastase and its endogeneous inhibitor seems to be a pathogenetic key mechanism in the origin of pulmonary emphysema (elastase-antielastase hypothesis). This hypothesis is supported by the observation, that low serum levels of alpha 1-antitrypsin can be observed in smokers with premature pulmonary emphysema. alpha 1-proteinase inhibitor is an acute phase protein with known structural and moleculargenetic aspects, which is synthesized by the liver and reaches the lung by the circulation. Its role is the inactivation of excessive neutrophil elastase in the pulmonary parenchyma, which is liberated during inflammation and destroys elastin and other components of extra-cellular connective tissue matrix. This is an overview on epidemiology, clinical aspects, genetics and molecular biology of this particular disease which was described in 1963.

[Pulmonary artery malformations]. / Pulmonale arteriovenöse Malformationen.

We report on two patients with pulmonary arteriovenous malformations (PAVM). An almost asymptomatic young man and an elderly woman with severe dyspnoea illustrate paradigmatically various aspects of the clinical manifestation, diagnostic approach and treatment of this rare disorder. New aspects with respect to genetics, diagnosis and therapy are discussed. PAVM are often manifestations of hereditary teleangiectasia, which also affect blood vessels of the skin, mucous membranes, brain and liver. Transcatheter embolotherapy is a safe, effective and minimally invasive treatment option, which seems to be replacing surgical resection as first-line therapy in many cases.

[Binding of LPS to CD14]. / Bindungsmodalitäten von LPS an CD14.

The 53 kDa glycoprotein CD14 (cluster of differentiation No. 14, defined by monoclonal antibodies of the 1st Leukocyte Typing Workshop) is expressed on monocyte surfaces and was identified 1990 as an endotoxin receptor (1). The binding of endotoxin to CD14 was mediated by a LPS-binding protein (LBP) present in serum.

Dandy-Walker(like) malformation, atrio-ventricular septal defect and a similar pattern of minor anomalies in 2 sisters: a new syndrome?

We report on sisters with similar craniofacial anomalies, a brain malformation in the area of the posterior fossa, and a congenital heart defect. The craniofacial findings include macrocephaly, a prominent forehead and occiput, foramina parietalia, hypertelorism, downslanting palpebral fissures, a depressed nasal bridge, narrow palate, and apparently low-set ears. Patient 1 had a Dandy-Walker malformation with communicating hydrocephalus, aplasia of the posterior portion of the cerebellar vermis, and high insertion of the confluent sinus, while in patient 2, a Dandy-Walker variant was found with aplasia of the cerebellar vermis and hypoplasia of the hemispheres, large cisterna magna, high insertion of the confluent sinus, but no hydrocephalus. Both sibs were moderately mentally retarded. The older sister had a complete atrio-ventricular canal and died after unsuccessful heart operation at 3 1/2 years. The younger had a successful operation on a cleft mitral valve and septum primum defect. Chromosomes were normal. The occurrence of a distinct and similar pattern of congenital anomalies in sisters born to healthy parents points toward a "new" syndrome caused by the homozygous state of an autosomal recessive gene.