The role of reactive nitrogen intermediates in modulation of gametocyte infectivity of rodent malaria parasites

Direct feeding of Anopheles stephensi mosquitoes on mice infected with Plasmodium vinckei petteri showed that, during the periods of schizogony in the blood, the infectivity of gametocytes was markedly reduced. This could be prevented by prior injection of the L-arginine analogue, Nw-nitro-L-arginine (NwNLA) showing that the altered infectivity was due to reactive nitrogen intermediates (RNI). Similar effects on transmission of P. yoelii nigeriensis were demonstrated in vitro by membrane feeding of the mosquitoes. The in vitro reduction in infectivity could be reversed by injecting the L-arginine analogue either into the infected mouse donor of serum, or into the membrane feeding chamber. Elevated levels of TNF and IL-6 were demonstrated during the course of infection but did not correlate well with nitrogen radical activity. Similarly, direct measurements of NO₂- and NO₃- did not reflect the nitrogen radical activity revealed by addition of the specific L-arginine analogue.     

The age dependence of stereotyped behaviours in blind infants and preschoolers

As part of a research programme on early intervention and family care for blind infants and preschoolers, the Bielefeld Parents' Questionnaire for Blind and Sighted Infants and Preschoolers was given to 85 parents of congenitally blind children. All 85 children (from 5 to 72 months) in the sample were totally blind and had no further serious disabilities. A comparison of five age groups of blind infants and preschoolers indicated that the repertoire of stereotyped behaviour patterns depended on age. After expanding from the first to the second year of life, the range of different stereotyped behaviours decreased from the age of 3 years up to school enrollment. The amount of stereotyped behaviours showed a similar course. Among the individual stereotyped behaviours, only the frequency of eye poking and body rocking increased from the first to the second year of life and then maintained a relatively high level across the entire preschool age range. The situational and person-specific conditions under which stereotyped behaviours could typically be observed also appeared to change with the child's age. While in the first years of life, monotony and arousal situations dominated among the elicited stereotyped behaviours, the 4- to 6-year-old blind children increasingly exhibited stereotyped behaviours in situations in which they were confronted with cognitive and concentrative demands. Various possible explanations of the age dependence of stereotyped behaviour patterns in blind infants and preschoolers are discussed.     

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.     

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.     

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.