Surface anatomy of the face in Down's syndrome: linear and angular measurements in the craniofacial regions

Measurements (23 projective linear, 2 angular) taken in the 6 craniofacial regions of 127 patients with Down's syndrome showed that 63.1% (1,836 of 2,908) were within normal limits and 36.9% (1,072) were outside them. Abnormal measurements were subnormal in 90.8% (973) and supernormal in 9.2% (99). All statistical summaries were based on z scores (adjusting for age and sex differences) classified into a small number of ranges to yield a simplified frequency distribution for each measurement. The purpose of the study was to identify the measurements closest to normal and those indicating the most severe degrees of sub- or supernormality. Approximately a quarter of normal measurements were classified as optimal, and half the subnormal or supernormal measurements were classified as severe. Intercanthal width had the highest frequency of optimal measurements (93.7%, 119 of 127), head circumference the smallest (28.6%, 36 of 126). Knowledge of the frequency of extreme abnormalities in the craniofacial regions will help during visual examination of patients with Down's syndrome. This study found the highest percentage of severely subnormal measurements in the orbital region (57.8%, 74 of 128) and the smallest in the labio-oral region (32.7%, 16 of 49). The measurement with the highest proportion of severely subnormal to all subnormal values was the palpebral fissure length (68%, 51 of 75), and the nose width had the smallest proportion (14.3%, 1 of 7).     

The effects of diaspirin cross-linked hemoglobin on the tone of human saphenous vein

Diaspirin cross-linked hemoglobin (DCL-Hb), when infused into animals, causes vasoconstriction thought to be caused by nitric oxide (NO) binding by the hemoglobin molecule. The purpose of this study was to ascertain whether DCL-Hb causes vasoconstriction in human saphenous vein taken from patients undergoing myocardial revascularization and whether NO scavenging is the mechanism. The direct effect of DCL-Hb on saphenous vein tone was tested by adding increasing concentrations (10(-8) to 10(-5)M) of the drug. In an additional series of experiments, the influence of DCL-Hb on the dilator response to endothelial dependent and independent vasodilators was tested. This was achieved by attempting either to reverse the effects of acetylcholine, sodium nitroprusside, or S-nitrosylglutathione with prior incubation with DCL-Hb or to inhibit the dilator response in vessels preconstricted with 10(-6)M norepinephrine. There was no effect of DCL-Hb alone on saphenous vein tone. DCL-Hb significantly reduced vasodilatation with all vasodilators (P < 0.05). After maximal relaxation with sodium nitroprusside and s-nitrosylglutathione, there was significant vasoconstriction with DCL-Hb at concentrations larger than 10(-6)M, (P < 0.05). The authors conclude that DCL-Hb does not constrict human saphenous vein but can affect vessel tone by reversal of the effect of endogenously or exogenously released NO.     

A randomised controlled trial comparing meat‐based with human cadaveric models for teaching ultrasound‐guided regional anaesthesia

The aim of this prospective, blinded, randomised controlled study was to compare novices' acquisition of the technical skills of ultrasound‐guided regional anaesthesia using either a meat phantom model or fresh‐frozen human cadavers. The primary outcome was the time taken to successfully perform an ultrasound‐guided sciatic nerve block on a cadaver; secondary outcomes were the cumulative score of errors, and best image quality of the sciatic nerve achieved. After training, the median (IQR [range]) time taken to perform the block was 311(164–390 [68–600]) s in the meat model trained group and 210 (174–354 [85–600]) s in the fresh‐frozen cadaver trained group (p = 0.24). Participants made a median (IQR [range]) of 18 (14–33 [8–55]) and 15 (12–22 [8–44]) errors in the two groups respectively (p = 0.39). The image quality score was also not different, with a median (IQR [range]) of 62.5 (59.4–65.6 [25.0–100.0])% vs 62.5 (62.5–75.0 [25.0–87.5])% respectively (p = 0.58). The training and deliberate feedback improved all participants' block performance, the median (IQR [range]) times being 310 (206–532 [110–600]) s before and 240 (174–354 [85–600]) s after training (p = 0.02). We conclude that novices taught ultrasound scanning and needle guidance skills using an inexpensive and easily constructed meat model perform similarly to those trained on a cadaveric model.     

Effects of Speaking Rate on Word Recognition in Parkinson's Disease and Normal Aging

Current theories of basal ganglia function emphasize their role in the integration of sensory information into motor activities, particularly in the control of movement timing. People with basal ganglia disorders such as Parkinson's disease exhibit poor temporal control of movements, in general and articulation in particular, as demonstrated by irregular speaking rate, reduced stress contrasts, and reduced movement durations and velocities. Previous research has implicated sensory deficits as contributory factors in limb movement control in patients with Parkinson's disease; however, the relation between sensory deficits and speech-movement abnormalities has not been documented. In the present study, the existence of perceptual processing difficulties of speaking rate was investigated in subjects with Parkinsonian dysarthria (PD). Comparisons in perception were made between subjects with PD, neurologically normal geriatrics (GN) and neurologically normal young adults (YN) for accuracy in identification of words presented at different speaking rates. We hypothesized that word-identification scores would be lower for PD and GN subjects compared to the YN subjects, an effect that was supported by the data. We also expected that there would be differences between the GN and PD subjects in their accuracy of word identification at a faster speaking rate, an hypothesis that was not supported by the data. Rather, GN and PD subjects differed in identification scores for words spoken at a slow rate. PD subjects who had faster habitual speaking rates (HSR) had significantly lower word-identification scores in the slow compared to conversational rate conditions, a relation that was significant r = +0.64). These data suggest the need to consider perceptual deficits as an additional factor that contributes to rate variations in PD speech.