Effects of 1% chlorhexidine gel treatment on sympathetic adrenergic nerves in human buccal mucosa

The effect of treatment with a commercially available 1 % chlorhexidine gel (Hibitane Dental) in custom trays for 14 days (10 min daily) on the sympathetic adrenergic nerves in biopsies from human buccal mucosa was investigated. Chemical assay of endogenous noradrenaline concentration and immunocytochemical demonstration of tyrosine hydroxylase served as markers for structural and functional integrity of the adrenergic nerves. The mean concentration of noradrenaline in chlorhexidine treated tissues did not differ from the mean concentration in control. No morphologic or fluorescence intensity differences of the tyrosine hydroxylase immunoreactivity were found in the chlorhexidine treated tissues when compared to controls. These findings indicate that a relatively intense treatment with a commercially available 1% chlorhexidine gel does not affect the adrenergic innervation of human buccal mucosa.     

Fibrocartilage in the transverse ligament of the human acetabulum

Biomechanical experiments on isolated hip joints have suggested that the transverse ligament acts as a bridle for the lunate articular surface of the acetabulum during load bearing, but there are inherent limitations in such studies because the specimens are fixed artificially to testing devices and there are no modifying influences of muscle pull. Further evidence is thus needed to substantiate the theory. Here we argue that if the horns of the lunate surface are forced apart under load, the ligament would straighten and become compressed against the femoral head. It would thus be expected to share some of the features of tendons and ligaments that wrap around bony pulleys and yet previous work has suggested that the transverse ligament is purely fibrous. Transverse ligaments were removed from 8 cadavers (aged 17–39 y) and fixed in 90% methanol. Cryosections were immunolabelled with antibodies against collagens (types I, II, III, VI), glycosaminoglycans (chondroitins 4 and 6 sulphate, dermatan sulphate, keratan sulphate) and proteoglycans (aggrecan, link protein, versican, tenascin). A small sesamoid fibrocartilage was consistently present in the centre of each transverse ligament, near its inner surface at the site where it faced the femoral head. Additionally, a more prominent enthesis fibrocartilage was found at both bony attachments. All fibrocartilage regions, in at least some specimens, labelled for type II collagen, chondroitin 6 sulphate, aggrecan and link protein, molecules more typically associated with articular cartilage. The results suggest that the ligament should be classed as containing a ‘moderately cartilaginous’ sesamoid fibrocartilage, adapted to withstanding compression. This supports the inferences that can be drawn from previous biomechanical studies. We cannot give any quantitative estimate of the levels of compression experienced. All that can be said is that the ligament occupies an intermediate position in the spectrum of fibrocartilaginous tissues. It is more cartilaginous than some wrap‐around tendons at the wrist, but less cartilaginous than certain other wrap‐around ligaments, e.g. the transverse ligament of the atlas.     

Unreliable residual volume measurement after increased water load diuresis

BACKGROUND: The aim of the present study was to examine whether increased water load intake prior to ultrasound examination of the lower urinary tract, affects the measurement of postvoid residual urine volume. PATIENTS AND METHODS: Ninety four male patients with postvoid residual volumes after increased water load diuresis of more than 100 mL (PVR1) were included in the present study. All patients underwent a second PVR measurement by an urologist with a portable transabdominal bladder ultrasound scan without having received an increased water load (PVR2). A comparison of the measurements was performed and the PVR values were also correlated with other parameters, such as age, International Prostate Symptom Score, prostate volume and serum prostate-specific antigen (PSA) values. RESULTS: Postvoid residual urine volume after increased water load diuresis (PVR1) differed from that recorded after normal bladder filling and voiding at first desire (PVR2), with the former being larger than the later in every patient (P < 0.001). The PVR values, PVR1 and PVR2, were independent to patient age, symptom score prostate volume and PSA value. CONCLUSIONS: Measurement of postvoid residual volume in a relaxed patient, who voids at first desire, represents everyday life and should be the correct method of testing.     

Safety of Antitachycardia Pacing in Patients with Implantable Cardioverter Defibrillators and Severely Depressed Left Ventricular Function

The purpose of this study was to investigate the efficacy and safety of antitachycardia pacing (ATP) in third-generation implantable Cardioverter defibrillators (ICDs) for terminating spontaneously occurring ventricular tachycardias (VTs) in patients with severely depressed left ventricular (LV) function. Ninety-one patients with active ATP were followed for 16 ± 13 months. During this period, 775 VT episodes occurring in 36 patients were treated by ATP. The patients were divided into two groups according to their LV ejection fraction (LVEF): group A with LVEF ± 30% (n = 20), and group B with LVEF ± 30% (n = 16). There were no differences between both groups in age, gender, underlying heart disease, indication for ICD therapy, or drug therapy. The VT rates were comparable (group A: 183 ± 16 beats/min; group B: 180 ± 21 beats/min; P = NS). Eighty-three percent of all episodes (n = 332) in group A and 93% of the VTs (n = 443) in group B were ATP terminated (P ± 0.01). Ten percent of VTs in group A were accelerated by ATP into the ventricular fibrillation zone versus 2% in group B (P ± 0.01). The individual termination rate and acceleration rate per patient were comparable in both groups. All VT episodes unresponsive to ATP were converted by backup shocks. The efficacy of first-shock therapy was similar in both groups (group A: 89%; group B: 97%; P = NS). The proportion of patients who needed at least one backup shock for unsuccessful ATP was comparable in both groups (group A: 65%; group B: 56%; P= NS). We conclude that ATP is effective and safe in patients with recurrent VTs and severely depressed LV function, and it can be safely programmed in this group of patients to minimize the use of shock therapy.     

Limitations of Dower's Inverse Transform for the Study of Atrial Loops during Atrial Fibrillation

Introduction: Spatial characteristics of atrial fibrillatory waves have been extracted by using a vectorcardiogram (VCG) during atrial fibrillation (AF). However, the VCG is usually not recorded in clinical practice and atrial loops are derived from the 12-lead electrocardiogram (ECG). We evaluated the suitability of the reconstruction of orthogonal leads from the 12-lead ECG for fibrillatory waves in AF.
Methods: We used the Physikalisch-Technische Bundesanstalt diagnostic ECG database, which contains 15 simultaneously recorded signals (12-lead ECG and three Frank orthogonal leads) of 13 patients during AF. Frank leads were derived from the 12-lead ECG by using Dower's inverse transform. Derived leads were then compared to true Frank leads in terms of the relative error achieved. We calculated the orientation of AF loops of both recorded orthogonal leads and derived leads and measured the difference in estimated orientation. Also, we investigated the relationship of errors in derivation with fibrillatory wave amplitude, frequency, wave residuum, and fit to a plane of the AF loops.
Results: Errors in derivation of AF loops were 68 ± 31% and errors in the estimation of orientation were 35.85 ± 20.43°. We did not find any correlation among these errors and amplitude, frequency, or other parameters.
Conclusions: In conclusion, Dower's inverse transform should not be used for the derivation of orthogonal leads from the 12-lead ECG for the analysis of fibrillatory wave loops in AF. Spatial parameters obtained after this derivation may differ from those obtained from recorded orthogonal leads.     

Angiographic and Histologic Course after Implantation of Balloon Expandable Intravascular Stents in Miniswine Coronary Arteries: Short- and Mid-Term Observations

Sixteen balloon expandable Medtronic Wiktor tantalum stents were implanted in the major coronary arteries of six minipigs, which were maintained on a normal diet and given 500 mg aspirin per day. Angiographic and histologic examinations were performed 6 and 26 weeks after implantation. Angiographically reviewed, stenting increased the inner diameter of the coronary arteries from 2.61 ± 0.44 to 3.02 ± 0.34 mm (n = 16, P ≤ 0.001). Six weeks later, this value was reduced from 2.98 ± 0.35 to 2.33 ± 0.46 mm (n = 9, P ≤ 0.05), and between 6 and 26 weeks, an increase from 2.17 ± 0.44 to 2.93 ± 0.40 mm occurred (n = 6, P ≤ 0.05). Histologic evaluation at 26 weeks after stent implantation revealed an increase of the cross-sectional area of the total vessel from 4.30 ± 1.09 to 5.50 ± 1.67 mm² (n = 9; P ≤ 0.01). This was due to widening of the total vessel and intimal proliferation, which amounted to 1.19 ± 0.46 mm² within the stented segment, as compared to 0.03 ± 0.03 mm² in control sections (P ≤ 0.01). The areas of free vessel lumen, media muscularis, and adventitia remained unchanged. In 15 of the 16 hislologically examined coronary arteries, the internal elastica was fractured at the site of stent implantation. Twelve stents had also penetrated through the external elastica without evidence of wall hemorrhage. Thirteen out of 16 stents were angiographically followed, of which 12 were patent at the final reangiography. In one animal, acute thrombosis of the stented vessel after guidewire induced coronary artery spasm caused chronic right heart failure due to right ventricular myocardial infarction. Sudden death occurred in another pig 2 hours after successful implantation of three grossly oversized stents (inner vessel diameter: 2.4 ± 0.2 mm, stent diameter 3.2 ± 0.5 mm). Autopsy revealed extensive dissections of the media with subsequent vessel occlusion. It is concluded that Medtronic Wiktor stents can be placed easily, even in more distal or curved coronary arteries. Despite antiaggregational medication, intimal proliferation is observed early after implantation, reaches a maximum at about 6 weeks, and is followed by a regression 26 weeks poststenting. At 26 weeks follow-up, the free vessel lumen at the stent site was not significantly reduced as compared to control segments. Proper adjustment of internal vessel diameter and stent diameter is necessary to prevent major dissections and thrombotic occlusions.     

Mitral Valve Repair for Isolated Mitral Valve Regurgitation: A Plea for Early Operation

Although mitral valve repair is a recognized method to surgically treat mitral valve regurgitation, the ideal timing of the operation still is controversial. The goal of this study was to study the long-term results of mitral valve repair focusing on symptomatic versus nonsymptomatic patients. From October 1988 to June 1994, 262 patients (mean age = 57.4) with isolated mitral regurgitation underwent mitral valve repair. Seventy-nine patients (group I) were nonsymptomatic (NYHA Class I or II) and 184 (group II) were severely symptomatic (NYHA III or IV). The surgical techniques have been mainly those described by Alain Carpentier. All patients but three had an annuloplasty with a Carpentier ring. Mean follow-up was 4.02 ± 0.1 years and total follow-up, 972 patient-years. There was one operative death (0.4%). Postoperative Doppler echocardiography showed satisfactory mitral valve function in 97% of the patients and two cases of systolic anterior motion (1%). At 7 years, actuarial survival was 80%± 9%, 95%± 5%, 75%± 11% for the total group, group I, and group II, respectively. At 7 years, freedom from thromboembolic or bleeding complications and reoperation was 96%± 4%, 93%± 8%, and 94%± 3%, respectively. Mitral valve repair for isolated mitral valve regurgitation provides satisfactory survival at 7 years. The long-term survival is better when patients are operated at an early stage when they are still nonsymptomatic.