Inspiratory coactivation of the genioglossus enlarges retroglossal space in laryngectomized humans.

To investigate the relationship between the electrical activity of the genioglossus (GG-EMG) and associated tongue movement, seven laryngectomized subjects breathing through a tracheal stoma (without pressure or flow change in the upper airway) were studied in the supine position. Tongue movement, with the use of lateral fluoroscopy, and GG-EMG expressed as a percentage of maximum voluntary genioglossal activation were monitored simultaneously during 1) spontaneous inspiration (SI), 2) resistive loaded inspiration (LI), and 3) rapid inspiration (RI). Tongue position during each maneuver was compared with its position during spontaneous expiration. Peak GG-EMG during the three maneuvers was significantly different from each other (SI: 5.4 +/- 1.6, LI: 11.9 +/- 1.8, and RI: 51.6 +/- 9.4 (SE) %, respectively). Associated forward movement of the posterior aspect of the tongue was minimum during SI; however, significant movement was observed during LI, and this was increased during RI. Significant covariance existed between peak GG-EMG and this movement. Genioglossal coactivation with inspiration enlarges the glossopharyngeal airway, particularly in its caudal part. In subjects with intact upper airways, this activation may protect or enhance upper airway patency in an effort-dependent manner.

Population differentiation in randomly amplified polymorphic DNA of red-cockaded woodpeckers Picoides borealis.

Random amplified polymorphic DNA (RAPD) phenotypes generated by 13 primers were scored for 101 individuals in 14 populations of the endangered red-cockaded woodpecker Picoides borealis. Although no population-specific markers were found, the frequencies of several markers differed significantly among populations. Application of the recently developed AMOVA method (analysis of molecular variance; Excoffier, Smouse & Quattro 1992) showed that more than 90% of phenotypic variance occurred among individuals within populations; of the remaining variance, half was attributed among groups of geographically adjacent populations and half among populations within those groups. The statistical significance of these patterns was supported by Monte Carolo sampling simulations and permutation tests. Estimation of allele frequencies from phenotypes provided somewhat weaker evidence for population structure, although among-population variance in allele frequencies was detectable (Fst = 0.19; chi 2(169) = 509.3, P < 0.0001). UPGMA cluster analyses based on Rogers' (1972) genetic distance revealed grouping of some geographically proximate populations. A Mantel test indicated a positive (r = 0.16), although not significant, correlation between geographic and genetic distances. We compared a subset of our RAPD data with data from a previous study that used allozymes (Stangel, Lennartz & Smith 1992). RAPD (n = 75) and allozyme (n = 245) results based on samples from the same ten populations showed similar patterns. Our study indicates that RAPDs can be helpful in differentiating populations at the phenotypic level even when small sample sizes, estimation bias, and inability to test for Hardy-Weinberg equilibrium complicate the genotypic interpretation. Lack of large differences among populations of red-cockaded woodpeckers may allow flexibility in interpopulation translocations, provided factors such as habitat preference, latitudinal direction of translocation, and status of donor populations are considered.

245 transaxillary arteriograms in arteriopathic patients: success rate and complications.

Two hundred and forty-five transaxillary arteriograms were attempted at Charing Cross Hospital between 1982 and 1991 on 195 arteriopathic patients (mean age 64 years) in whom the femoral route was contra-indicated due to absent pulses (94), previous surgery (108), femoral artery aneurysm (5), severe aorto-iliac disease (8) or previous failure by the femoral route (30). Most arteriograms (211) were carried out to investigate peripheral vascular disease, the others were carried out to perform transluminal angioplasty (16) to assess cerebrovascular disease (10) and to investigate arterial insufficiency of the kidneys, alimentary tract and upper limb (8). There were two (0.8%) technical failures where the axillary artery could not be punctured. Selective catheterization of the carotid, vertebral, axillary, lumbar, renal, superior mesenteric, inferior mesenteric, iliac, femoral or popliteal arteries was performed in the course of 38 procedures. There were three (1.2%) serious complications related to the puncture site, a large haematoma followed by a prolonged neurological deficit of the brachial plexus in a hypertensive patient receiving haemodialysis, and thrombosis of the axillary artery in two other patients both of whom responded to surgical thrombectomy. There were three (1.2%) serious systemic complications, two patients had a cardiac arrest and although both were successfully resuscitated one became anuric and died from renal failure and septicaemia 4 weeks later. One patient with a history of transient ischaemic attacks developed a similar transient episode at the end of the procedure. Compared with six series of 290 attempted brachial artery catheterizations in patients where the femoral route was contra-indicated which have been reported since 1986, our series of 245 attempted axillary artery catheterizations had a significantly higher incidence of technical success at the first attempt (P = 0.021) and a lower incidence of vascular complications requiring surgery or angioplasty which was not statistically significant. Our conclusion is that transaxillary arterial catheterization has a high rate of technical success (99%) and should be considered in patients where the femoral route is contra-indicated due to arterial disease.

Hyponatraemia following transurethral resection of the prostate.

In a prospective study of 100 patients undergoing transurethral resection, changes in serum sodium were estimated during the per-operative and post-operative periods. The weight of prostate resected and the volume of irrigant fluid used influenced the changes in serum sodium. In 93 patients these changes were not statistically significant. In only seven patients were significant falls in serum sodium recorded, in one case to a level of 103 mmol/l. All seven exhibited the clinical features of the transurethral syndrome and there was one post-operative death which we attributed to it. The TUR syndrome undoubtedly exists and its incidence in this series was 7%. Its pathogenesis and clinical management are discussed.