The sense of smell is not strongly affected by ambient temperature and humidity: a prospective study in a controlled environment.

INTRODUCTION: The sense of smell is dependent on environmental conditions. In this study, we analysed the effect of temperature and humidity on the ability to smell. METHODS: Using the controlled setting of a hypobaric climate chamber 50 healthy participants (40 men, 10 women; mean age of 33 years) completed repeated testing in 4 different settings-cold/dry, cold/humid, warm/dry, warm/humid. The temperatures were 20-35 °C, respectively, and the humidity was set at 30-75%. Testing was performed using the "Sniffin' Sticks" test battery (odour threshold, discrimination and identification) in a semi-randomised order and in controlled atmospheric pressure conditions. RESULTS: The analysis showed that neither temperature nor humidity had a significant effect on olfactory test results. This indicates that olfactory functions in healthy, young subjects with an excellent sense of smell are not strongly affected by temporary changes in environmental conditions.

[Improvements in implantable mechanical circulatory support systems : literature overview and update]. / Fortschritte bei implantierbaren mechanischen Kreislaufunterstüzungssystemen : Literaturübersicht und Update.

In recent years, ventricular assist devices (VAD) supporting the left (LVAD), the right (RVAD) or both ventricles (BVAD) have rapidly emerged as the standard of care for advanced heart failure patients. Both the numbers and ages of patients in which they are used are rising worldwide, especially when used as a permanent support (bridge to destination, BTD). Due to the continuing lack of donor organs, these devices now represent a viable alternative to bridge patients to transplantation (BTT), with a 1-year survival rate of 86%. BTD, especially in long-term support, might be a valid, and the sole, option for those patients in whom heart transplantation is contraindicated. Patient selection, pre- and intra-operative preparation, as well as the timing of VAD implantation are important factors critical to successful circulatory support. While BTT remains the goal in the majority of patients, the number of permanent VADs (i. e. BTD) is rising significantly. Although explantation of a VAD system as a bridge to recovery (BTR) can be considered in only a small number of patients, it represents a very special part of this therapy modality.

Transcranial Doppler sound detection of cerebral microembolism during transapical aortic valve implantation.

OBJECTIVE: Transapical aortic valve implantation (TAVI) is a new method that might reduce the surgical risk of conventional surgical aortic valve replacement in very high-risk patients. Increased downstream microembolization is expected in transapical aortic valve implantation. However, whether it usually occurs, how often, and its clinical relevance are not known. We report the results of ultrasound microembolic signal detection in the middle cerebral artery during the procedure. METHODS: Fifty patients (mean age: 80 ± 5 years; mean EuroSCORE: 36 ± 13 %) underwent transapical aortic valve implantation. Intraoperative transcranial Doppler (TCD) sound examination of both middle cerebral arteries (MCA) was used to identify high-intensity transient signals (HITS) and microembolic signals (MES) during seven phases of the procedure. Pre- and postoperative computed tomography of the brain and clinical neurological examinations were performed preoperatively and daily during the first postoperative week. RESULTS: During the procedure, HITS [right MCA: 435 ± 922 (range 9-5765); left MCA: 471 ± 996 (range 24-6432)] and MES [right MCA: 78 ± 172 (range 1-955); left MCA: 62 ± 190 (range 2-1553)] were detected in all patients. Most of the MES were recorded during valvuloplasty [right MCA: 3 ± 5.6 (range 0-31); left MCA: 2 ± 4.9 (range 0-30)] and positioning of the prosthetic valve in the aortic position [right MCA: 6 ± 5 (range 0-22); left MCA: 2 ± 6.9 (range 0-38)]. Postoperatively, there were no clinical signs of new cerebral embolism. CONCLUSIONS: Cerebral microemboli were detected by intraoperative transcranial Doppler sound examinations in all patients during transapical aortic valve implantation. Most of the signals were detected during balloon valvuloplasty and delivery of the prosthetic valve.

Precision of computer-aided volumetry of artificial small solid pulmonary nodules in ex vivo porcine lungs.

The purpose of this study was to investigate the precision of CT-based volumetric measurements of artificial small pulmonary nodules under ex vivo conditions. We implanted 322 artificial nodules in 23 inflated ex vivo porcine lungs in a dedicated chest phantom. The lungs were examined with a multislice spiral CT (20 mAs, collimation 16x0.75 mm, 1 mm slice thickness, 0.7 mm increment). A commercial volumetry software package (LungCARE VA70C-W; Siemens, Erlangen, Germany) was used for volume analysis in a semi-automatic and a manual corrected mode. After imaging, the lungs were dissected to harvest the nodules for gold standard determination. The volumes of 202 solitary, solid and well-defined lesions without contact with the pleura, greater bronchi or vessels were compared with the results of volumetry. A mean nodule diameter of 8.3 mm (+/-2.1 mm) was achieved. The mean relative deviation from the true lesion volume was -9.2% (+/-10.6%) for semi-automatic and -0.3% (+/-6.5%) for manual corrected volumetry. The subgroup of lesions from 5 mm to <10 mm in diameter showed a mean relative deviation of -8.7% (+/-10.9%) for semi-automatic volumetry and -0.3% (+/-6.9%) for manually corrected volumetry. We conclude that the presented software allowed for precise volumetry of artificial nodules in ex vivo lung tissue. This result is comparable to the findings of previous in vitro studies.

Oral surgical management of patients with mechanical circulatory support.

After the introduction of mechanical circulatory support (MCS) for treatment of patients with severe cardiogenic shock, the survival rate of these patients increased significantly. Temporary MCS may be applied over a period of several days up to months prior to heart transplantation (HTx). Oral surgical management of patients with MCS is seriously complicated by a combination of anticoagulant and antiaggregant medication. Moreover, contact of blood with artificial surfaces, i.e. polyurethane and silicone, may increase the risk of thromboembolic events and infections. A total of 32 patients with MCS (29 men and three women with a median age 48 years [range 27-60 years]) were examined for odontogenic foci, treatment needs and local and cardiovascular complications after oral surgical intervention. In 27 patients (84%) at least one potential focus was diagnosed. Following tooth extraction 4 out of 6 patients presented with local haemorrhage (n=3) and thromboembolic events (n=2). Generally MCS has to be considered a relative contraindication for elective oral surgical interventions.

Outpatients on biventricular assist devices.

As waiting times for transplants have lengthened, long-term mechanical circulatory support (MCS) has become more common in patients who present with severe cardiogenic shock leading to multiorgan failure. With these patients, we used the biventricular assist device (BVAD, Berlin Heart). In this report, we will describe our 4 years of experience with 11 patients on a BVAD who were discharged home while awaiting transplantation. The 11 patients underwent BVAD implantation from 1997 to 2000. These were 2 women and 9 men. The mean support time was 382 days (range: 156 - 567). The indication for BVAD was cardiomyopathy--six dilated, one restrictive and four ischemic. These patients were monitored for infections, thromboembolic events, bleeding complications, and psychological effects during the time they spent at home. Our experience shows that all of the patients could leave hospital following sufficient training for dressings and anticoagulation after recovering completely from secondary organ dysfunction. The mean time period the patients spent at home was 48 days (range: 3 - 182) days. Seven patients (63 %) had to be readmitted to the hospital--due to transitory ischemic attacks in two cases, hemorrhoidal bleeding in one and wound infections in four cases. One patient died of a traumatic accident during sexual activity. The use of a BVAD is feasible for outpatient use as a bridge to transplantation. It ensures the survival of the patient, enables recovery from multiorgan failure and offers an acceptable quality of life.

Revascularization of the occluded right coronary artery during left ventricular assist device implantation.

A 62-year-old man with end-stage ischemic cardiomyopathy and left ventricular function of 20% was evaluated for heart transplantation. Cardiac catheterization revealed proximal occlusion of the dominant right coronary artery (RCA) with collateral blood flow and significant stenosis in the distal part, but no significant re-occlusions of the stented left coronary artery and no significant stenosis of the left circumflex artery. When the patient became catecholamine dependent, Novacor left ventricular assist device (LVAD) implantation, as a bridge to transplantation, was considered and the patient operated upon. To avoid ischemic right heart failure after LVAD implantation, a concomitant re-vascularization of the distal RCA was performed. The post-operative course was uneventful. Five weeks later, a control angiogram showed the patent bypass graft. The distal stenosis of the RCA was treated successfully with dilation and stent implantation. The patient is presently in stable condition on LVAD and awaits transplantation as an outpatient.

[Advances and perspectives in mechanical heart assist]. / Fortschritte und Perspektiven des mechanischen Herzersatzes.

Mechanical circulatory support devices were first developed to permanently replace the failing heart. Today, however, the majority of these devices are used as a mechanical bridge in patients awaiting heart transplantation. With this indication, important information on using mechanical assist devices has been assembled. We present our experience, which has been gained since 1987 in the area of patient selection, post-implant patient care and device maintenance. More than 450 patients have since been implanted with assist devices at our institution. Mechanical circulatory support may not only lead to recovery from secondary organ failure, but also to myocardial remodeling and recovery of the heart function in some patients. Additionally we report our experience with a newly developed implantable axial flow pump and discuss the possibility and costs of permanent support in some patients.

The trifluorophosphonium ion, PF3H+, preparation and structure.

The PF3H+ ion is prepared as PF3H+.SbF6-.HF by protonation of PF3 with HF/SbF5 at low temperatures in anhydrous HF. Crystals are obtained directly from this solvent. A crystal structure determination shows the presence of a pseudo-tetrahedral PF3H+ ion with a mean P-F distance of 148.7(2) pm, a P-H distance of 122(4) pm, and a mean PF2 angle of 106.1(1) degrees. Raman spectra were recorded of PF3H+SbF6-.HF and PF3D+.SbF6-.DF and assigned with the help of ab initio calculations. AsF3 does not react with HF/SbF5, whereas SF4 forms SF3+SbF6-.HF, which is isostructural with PF3H+SbF6-.HF.

[Progress and perspectives in mechanical circulatory support]. / Fortschritte und Perspektiven des mechanischen Herzersatzes.

Mechanical circulatory support devices were first developed to permanently replace the failing heart. Today, however, the majority of these devices are used as a mechanical bridge in patients awaiting heart transplantation. With this indication, important information on using mechanical assist devices has been assembled. We present our experience, which has been gained since 1987 in the area of patient selection, post-implant patient care and device maintenance. More than 450 patients have since been implanted with assist devices at our institution. Mechanical circulatory support may not only lead to recovery from secondary organ failure, but also to myocardial reremodeling and recovery of the heart function in some patients. Additionally we report our experience with a newly developed implantable axial flow pump and discuss the possibility and costs of permanent support in some patients.

Isolation and Structure of the OCNCO(+) Ion.

Strongly bent at the nitrogen atom (130.7 degrees ), the OCNCO(+) ion (see structure) is the closest relative to carbon suboxide OCCCO. According to calculations the linear OCNCO(+) ion is only a few kJ mol(-1) higher in energy.

Effect of alpha2-adrenoceptor stimulation on isolated canine Purkinje fiber contraction.

We have recently identified the presence of postjunctional alpha2-adrenoceptors in canine Purkinje fibers. In this study, we examined the effects of alpha2-adrenoceptor stimulation on the contraction strength of isolated Purkinje fibers. Exposure to the alpha2-adrenoceptor specific agonist and antagonist, UK 14,304 (5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine) and yohimbine (17-hydroxyyohimban-16-carboxylic acid methyl ester hydrochloride) alone at 0.1 microM respectively, did not produce any significant effect on Purkinje contraction strength. Purkinje contraction strength was augmented by isoproterenol (0.1 microM), forskolin (0.1 microM), or 8-bromo-adenosine cyclic 2',3'-monophosphate (8-bromo-cAMP, 10 microM). UK 14,304 significantly reversed the effects of isoproterenol and forskolin but not those of 8-bromo-cAMP on Purkinje contraction strength. After incubation with pertussis toxin, the positive inotropic effect of forskolin on Purkinje contraction strength remained intact, but the forskolin effect could no longer be reversed by UK 14,304. These results suggest that the postjunctional alpha2-adrenoceptors in canine Purkinje fibers are coupled to a pertussis toxin-sensitive G protein, probably Gi. Stimulation of the alpha2-adrenoceptor antagonizes the effect of beta-adrenoceptor stimulation on Purkinje contraction strength in an accentuated antagonism manner.

Preservation of papillary muscles and chordae during mitral valve replacement: possibilities and limitations.

The various techniques of preserving the chordal apparatus in mitral valve replacement applied in 1,453 cases at a single institution between 1986 and 1994 are described. The techniques include preservation of chordal attachment to the posterior mitral leaflet only and to both leaflets with five different technical variations. The specific advantages and risks of these techniques are demonstrated and discussed. It is concluded, that preservation of the entire subvalvular structures is feasible in almost all cases. Different procedures should be employed according to the variety of mitral disease, in particular with respect to mitral leaflet mobility.

Pericardial influence on internal defibrillation energy requirements.

There is no consensus regarding optimal positioning of patch leads for implantation of automatic implantable cardioverter defibrillators. We compared the energy (in joules) required for 50% and 80% successful termination of ventricular fibrillation with titanium-mesh patch leads outside intact normal pericardium and directly on the epicardium in 13 open-chest dogs. Talc was then instilled into the pericardial space to stimulate adhesion formation and pericardial thickening. After 3 weeks of recovery, thoracotomy and defibrillation testing were repeated in nine dogs with the patch leads outside the thickened, adherent pericardium. There were no significant differences in defibrillation energy requirements between locations (p greater than 0.10). In addition, a comparison of electrical impedance measurements at 10 joules showed no significant differences (p greater than 0.30). In this animal model, defibrillation energy requirements were not altered by positioning the patch leads outside normal intact pericardium rather than placing them directly on the epicardium. Furthermore, thickened, adherent pericardium interposed between the patch leads and the heart does not increase defibrillation energy requirements. These data suggest that placement of automatic implantable cardioverter defibrillator patch leads outside the pericardium in patients (including those with pericardial adhesions from previous cardiac operations) will not adversely affect defibrillation efficacy and thus can simplify the implantation procedure.