Severe hyponatraemia after plastic surgery in a girl with cleft palate, medial facial hypoplasia and growth retardation

A ten-year-old girl with middle face hypoplasia, cleft lip and palate developed severe hyponatraemia on the first day following surgery. Final diagnosis was inappropriate secretion of antidiuretic hormone (ADH) and complete hormonal investigation revealed partial deficit in growth hormone secretion. The incidence of hormonal deficiency associated to midline facial malformations is discussed.     

Rapid determination and NMR assignments of antiparallel sheets and helices of a scorpion and a cobra toxin

An NMR method is described which should provide a rapid means for determining and assigning antiparallel sheets and helices in small proteins. It begins by locating apparent NOESY crosspeaks which suggest the presence of the secondary structure; this is followed by searches for MCD patterns (Englander & Wand (1987) Biochemistry 22, 5953) which are characteristic of these structures. As a result, only spin-systems of the amino acids within the secondary structure need to be defined. A triple-stranded, antiparallel sheet and a helix have been found and assigned for both α-cobratoxin and the scorpion toxin AaH III.     

Structure and Neural Modulation of Cardiac Calcium Channels

Regulation of Cardiac Ca Channels . The L-type, voltage-gated calcium (Ca) current plays a key role in excitation and initiation of contraction in cardiac muscle cells and is partly responsible for the plateau of the action potential. The ionic channels underlying this current are targets for modulation by the autonomic nervous system. This article reviews recent developments in understanding how these channels are regulated by phosphorylation and G proteins and attempts to relate these findings to recent studies on the molecular structure of the Ca channel.     

Gene Expression of the Natriuretic Peptide System in Atrial Tissue of Patients with Paroxysmal and Persistent Atrial Fibrillation

INTRODUCTION: Circulating cardiac natriuretic peptides play an important role in maintaining volume homeostasis, especially during conditions affecting hemodynamics. During atrial fibrillation (AF), levels of plasma atrial natriuretic peptide (ANP) becomes elevated. The aim of this study was to gather information about gene expression of the natriuretic peptide system on the atrial level in patients with AF. METHODS AND RESULTS: Right atrial appendages of 36 patients with either paroxysmal or persistent AF were compared with 36 case matched controls in sinus rhythm for mRNA expression of pro- atrial natriuretic peptide (pro-ANP), pro-brain natriuretic peptide (pro-BNP), and their natriuretic peptide receptor type-A (NPR-A). We investigated patients without (n = 36) and with (n = 36) valvular disease. Persistent AF was associated with higher mRNA expression of pro-BNP (+66%, P = 0.04, in patients without valvular disease, and +69%, P < 0.01, in patients with valvular disease) and lower mRNA expression of NPR-A (-58%, P = 0.02, in patients without valvular disease, and -62 %, P < 0.01, in patients with valvular disease). The mRNA content of pro-ANP was only increased in patients with valvular disease (+12%, P = 0.03). No changes were observed in patients with paroxysmal AF. CONCLUSION: This study demonstrates that persistent, but not paroxysmal, AF induces alterations in gene expression of pro-BNP and NPR-A on the atrial level. Although AF generally is associated with an increase of plasma ANP level, a change in mRNA content of pro-ANP is only observed in the presence of concomitant valvular disease and is of minor magnitude.     

Contact‐Force Catheters: Efficacy Versus Safety? Case Report of 2 Atrioesophageal Fistulae

Contact‐force (CF) catheters appear to be more effective compared to standard ablation catheters for complex radiofrequency ablation including atrial fibrillation (AF) ablation when optimal CF >10 g is achieved. Some have suggested that this technology could also improve procedural safety. We report 2 cases of atrioesophageal fistulae (AEF), a rare but catastrophic complication of AF ablation. These are to our knowledge the first cases of AEF described after using CF catheters.     

Atrial Tachycardia Confined Within the Left Atrial Appendage

AT Confined Within the LAA. Left atrial tachycardias are often seen following catheter ablation of persistent atrial fibrillation (AF). We report here an unusual case where AF was converted to sinus rhythm following catheter ablation, but ongoing atrial tachycardia confined within the left atrial appendage (LAA) was observed. Although the LAA tachycardia was dissociated from the atrium in sinus rhythm, bidirectional conduction between the left atrium and the LAA was, however, demonstrated after tachycardia termination. (J Cardiovasc Electrophysiol, Vol. 21, pp. 933‐935, August 2010)     

Thresholds and Complications with Right Ventricular Septal Pacing Compared to Apical Pacing

Background: Right ventricular septal pacing has been proposed as an alternative to apical pacing. However, data concerning thresholds and requirement for lead repositioning with this technique are scant.
Methods: We reviewed data at implantation and follow-up of 362 consecutive recipients of the same model of active fixation lead (Medtronic 5076-58, Minneapolis, MN, USA) to avoid differences due to lead characteristics. Patients were divided into two groups according to whether the lead was positioned on the interventricular septum (n = 157) or at the right ventricular apex (n = 205). Thresholds, lead impedance, and requirement for lead repositioning were compared between groups at implantation and follow-up.
Results: There were no differences between the septal and apical groups in sensing and pacing thresholds or lead impedance, either at implantation or during a 24-month follow-up. In the septal group, the lead had to be repositioned in four patients (2.5%) due to lead dislodgement in two patients, acute threshold rise in one patient, and pericardial effusion in another patient (the lead had unintentionally been positioned on the anterior free wall in these last two patients). In the apical group, the lead had to be repositioned in eight patients (3.9%, P = 0.56) due to lead dislodgement in three patients and acute threshold rise in five patients.
Conclusions: Acute and chronic thresholds associated with septal pacing are similar to those observed with apical pacing, and risk of lead dislodgement is low. However, multiple radioscopic views must be used to avoid inadvertent positioning of the lead on the anterior free wall .     

Phosphorylation at Connexin43 Serine‐368 Is Necessary for Myocardial Conduction During Metabolic Stress

Connexin43 (Cx43) phosphorylation alters gap junction localization and function. In particular, phosphorylation at serine‐368 (S368) has been suggested to alter gap junctional conductance, but previous reports have shown inconsistent results for both timing and functional effects of S368 phosphorylation. The objective of this study was to determine the functional effects of isolated S368 phosphorylation. We evaluated wild‐type Cx43 (AdCx43) and mutations simulating permanent phosphorylation (Ad368E) or preventing phosphorylation (Ad368A) at S368. Function was assessed by optical mapping of electrical conduction in patterned cultures of neonatal rat ventricular myocytes, under baseline and metabolic stress (MS) conditions. Baseline conduction velocity (CV) was similar for all groups. In the AdCx43 and Ad368E groups, MS moderately decreased CV. Ad368A caused complete conduction block during MS. Triton‐X solubility assessment showed no change in Cx43 location during conduction impairment. Western blot analysis showed that Cx43‐S368 phosphorylation was present at baseline, and that it decreased during MS. Our data indicate that phosphorylation at S368 does not affect CV under baseline conditions, and that preventing S368 phosphorylation makes Cx43 hypersensitive to MS. These results show the critical role of S368 phosphorylation during stress conditions.