Haemodynamic complications after pneumonectomy: atrial inflow obstruction and reopening of the foramen ovale.

BACKGROUND: Haemodynamic impairments after pneumonectomy are rare complications and present in different forms. Due to a low awareness of these potential complications their diagnosis is difficult and often established late. The most important forms are: firstly reopening of a previously closed foramen ovale (PFO) caused by a combination of changed anatomic position of the left atrium and elevated pulmonary artery pressure leading to a significant right-left shunt; secondly diaphragmatic relaxation can lead to a dislocation of the liver into the right hemithorax, compressing the right atrium with subsequent inflow obstruction. METHODS: We retrospectively analysed our patient cohort from 1997 to 2006 for occurrence of haemodynamic complications requiring surgical intervention after pneumonectomy. RESULTS: Five hundred and forty-six pneumonectomies were performed in our centre during the observation period. Five patients (1 female, 4 male, age 59+/-9 years) with haemodynamic complications were identified. Two of those patients were referred with haemodynamic complications after pneumonectomy was performed in a peripheral centre. All patients had undergone right pneumonectomy for NSCLC (n=4) or atypical carcinoid (n=1). Two patients were readmitted 3 months and 2 years postoperatively due to increasing platypnoea and orthodeoxia. After closure of the reopened foramen ovale, which was found as the underlying pathological mechanism, respiratory symptoms were resolved. One patient required reintubation 2h postoperatively; after surgical closure of a PFO the respiratory situation significantly improved. One patient was readmitted due to right atrial inflow obstruction 17 months after right pneumonectomy. Underlying cause was a severe diaphragmatic relaxation with compression of the atrium by the liver. After diaphragmatic plication all symptoms resolved. However 1 year thereafter reoperation for recurrence of diaphragmatic elevation was required. One patient was readmitted 3 months after pneumonectomy and partial atrial resection for cyanosis and dyspnoea. Diagnostics revealed a PFO and a massive raise of the right diaphragm with compression of the right atrium. After surgical correction of the contorted foramen ovale and diaphragmatic plication, symptoms vanished. CONCLUSION: Haemodynamic alterations due to a reopened foramen ovale or right atrial inflow obstruction are rare, however they are severe complications after pneumonectomy. They occur at variable points in time after pneumonectomy. Diagnostic efforts are often made at a late stage due to a low awareness of the problem. Closure of the PFO either surgical or interventional and/or plication of the elevated diaphragm are mandatory. In our experience these complications occur only after right pneumonectomy.     

Time course of inner ear degeneration and deafness in mice lacking the Kir4.1 potassium channel subunit

The Kir4.1 gene (KCNJ10) encodes an inwardly rectifying K(+) channel subunit abundantly expressed in the CNS. Its expression in the mammalian inner ear has been suggested but its function in vivo in the inner ear is unknown. Because diverse human hereditary deafness syndromes are associated with mutations in K(+) channels, we examined auditory function and inner ear structure in mice with a genetically inactivated Kir4.1 K(+) channel subunit. Startle response experiments suggest that Kir4.1-/- mice are profoundly deaf, whereas Kir4.1+/- mice react like wild-type mice to acoustic stimuli. In Kir4.1-/- mice, the Reissner membrane is collapsed, the tectorial membrane is swollen, and type I hair cells and spiral ganglion neurons as well as their central processes degenerate over the first postnatal weeks. In the vestibular ganglia, neuronal cell death with apoptotic features is also observed. Immunostaining reveals that Kir4.1 is strongly expressed in stria vascularis of wild-type but not Kir4.1-/- mice. Within the spiral ganglion, Kir4.1 labeling was detected on satellite cells surrounding spiral ganglion neurons and axons. We conclude that Kir4.1 is crucial for normal development of the cochlea and hearing, via two distinct aspects of extracellular K(+) homeostasis: (1). in stria vascularis, Kir4.1 helps to generate the cochlear endolymph; and (2). in spiral and vestibular ganglia, Kir4.1 in surrounding glial cells helps to support the spiral and vestibular ganglion neurons and their projecting axons.     

Endothelial barrier protection by activated protein C through PAR1-dependent sphingosine 1-phosphate receptor-1 crossactivation

Endothelial cells normally form a dynamically regulated barrier at the blood-tissue interface, and breakdown of this barrier is a key pathogenic factor in inflammatory disorders such as sepsis. Pro-inflammatory signaling by the blood coagulation protease thrombin through protease activated receptor-1 (PAR1) can disrupt endothelial barrier integrity, whereas the bioactive lipid sphingosine 1-phosphate (S1P) recently has been demonstrated to have potent barrier protective effects. Activated protein C (APC) inhibits thrombin generation and has potent anti-inflammatory effects. Here, we show that APC enhanced endothelial barrier integrity in a dual-chamber system dependent on binding to endothelial protein C receptor, activation of PAR1, and activity of cellular sphingosine kinase. Small interfering RNA that targets sphingosine kinase-1 or S1P receptor-1 blocked this protective signaling by APC. Incubation of cells with PAR1 agonist peptide or low concentrations of thrombin (approximately 40 pM) had a similar barrier-enhancing effect. These results demonstrate that PAR1 activation on endothelial cells can have opposite biologic effects, reveal a role for cross-communication between the prototypical barrier-protective S1P and barrier-disruptive PAR1 pathway, and suggest that S1P receptor-1 mediates protective effects of APC in systemic inflammation.     

Differential coupling of m-cholinoceptors to Gi/Go-proteins in failing human myocardium

Muscarinic acetylcholine receptors (mAChRs) mediate their main cardiac effects via pertussis toxin-sensitive G-proteins. Physiological effects differ considerably between atrium and ventricle, and it is unknown to which extent these differences derive from selective receptor-G-protein coupling or further downstream events. We have characterized specific coupling between mAChRs and Gi/Go-protein isoforms in atrial and ventricular myocardium by agonist-dependent photoaffinity labeling with [(32)P]azidoanilido GTP (aaGTP) and immunoprecipitation in sarcolemmal membranes from terminally failing human hearts. The total amount of mAChRs, as determined by specific binding of [(3)H]QNB, was significantly higher in right-atrial (RA +/- SEM, 959 +/- 68 fmol/mg, n = 4) than in left-ventricular membranes (LV, 582 +/- 53 fmol/mg, n = 6). Standardized immunoblots revealed that Gialpha-2 was the predominant subtype in both regions. A 40-kDa splice variant of Goalpha (Goalpha-1 and/or Goalpha-3) was almost exclusively detectable in RA. Levels of Gialpha-3 and a 39-kDa splice variant of Goalpha (Goalpha-2) were also higher in RA. Basal aaGTP binding was higher in RA than in LV for all Gialpha/Goalpha subtypes. The carbachol (10 micromol/l)-induced increase in aaGTP binding was significantly higher in RA than in LV for Goalpha-1/3 (336 +/- 95% of LV, n = 4) and for Gialpha-3 (211 +/- 83%), lower for Gialpha-2 (42 +/- 5%), and was similar in both regions for Goalpha-2 (130 +/- 62%). The differential coupling of mAChRs in human RA and LV suggests that the initiation of different physiological responses to mAChR stimulation starts with signal sorting at the receptor-G-protein level.     

Extended stereotactic brain biopsy in suspected primary central nervous system angiitis: good diagnostic accuracy and high safety

Journal of Neurology - To evaluate the diagnostic accuracy and safety of extended stereotactic brain biopsy (ESBB) in a single center cohort with suspected primary angiitis of the central nervous...     

A retrospective analysis of autotransplanted teeth including an evaluation of a novel surgical technique

Clinical Oral Investigations - To assess survival rates and frequency of complications for immature and mature autotransplanted teeth after at least 1 year in function. All consecutive patients who...