The impact of treatment time and smoking on local control and complications in T1 glottic cancer

Low frequency impedance measurements of pure egg lecithin (phosphatidylcholine) bilayers have revealed the presence of four layers which can be attributed to the acyl chain, carbonyl, glycerol bridge and phosphatidylcholine regions of the lecithin molecule. Measurements on bilayers formed in the presence of unoxidised-cholesterol revealed that cholesterol molecules were located in the hydrocarbon region of the bilayer with its hydroxyl groups aligned with the carbonyl region of the lecithin molecules. Measurements of oxidised-cholesterol lecithin bilayers revealed that these molecules protruded less into the hydrocarbon region and their polar hydroxyl group aligned with the glycerol bridge region of the lecithin molecule.     

Modified radial head--capitellum projection in elbow trauma

A new technique is described for evaluating trauma to the elbow. The modified radial head--capitellum view is an alternative radiological projection to that described by Greenspan and Norman (the radial head--capitellum view). This new projection is useful in demonstrating minimally displaced or non-displaced fractures of the radial head, capitellum and coronoid process.     

The influence of surveillance methods on surgical wound infection rates in a tertiary care spinal surgery service

We studied 13 consecutive infants admitted to our Neonatal Intensive Care Unit over 37 months from 1 June 1994 to 30 June 1997, who were diagnosed with severe persistent pulmonary hypertension (PPHN) meeting extracorporeal membrane oxygenation (ECMO) criteria as defined by Bartlett and/or Short. They were managed with conservative ventilation strategy, with emphasis on the use of moderate ventilatory pressures whilst avoiding paralysis. Peak inspiratory pressure (PIP) on intermittent mandatory ventilation was adjusted according to adequate chest excursion. High PIP was avoided. Two main ventilatory techniques were used: 1) low ventilatory rate < or = 40/min, PIP 20 to 30 cmH2O, inspiratory time (IT) 0.5 seconds, positive end-expiratory pressure (PEEP) 5 cmH2O, and 2) high ventilatory rate 100/min, PEEP 0 cmH2O, IT 0.3 seconds. The aim was to keep preductal PaO2 > or = 50 mmHg. We did not sought to achieve alkalotic pH or low PaCO2. When PIP requirements exceeded 30 to 35 cmH2O, the use of an alternative rescue therapy such as pulmonary vasodilator, high frequency ventilation and/or surfactant were considered. Only 1 infant died of PPHN. Low mortality due to PPHN can be achieved using this strategy. There is a need for a randomised controlled trial to compare this strategy with other alternative treatment strategies.     

NMDA-receptor antagonist requirements in conantokin-G

A series of variants of the neuroactive 17-residue gamma-carboxyglutamate-(Gla)-containing polypeptide, conantokin-G (con-G), were synthesized with the intention of determining those features that were important for its N-methyl-D-aspartate (NMDA) receptor-targeted antagonist activity and for adoption of its divalent cation-dependent alpha-helical conformation. Employing the binding of [3H]dizolcipine (MK-801) as an assay for open receptor ion channels in rat brain membranes, which displays inhibition by con-G (IC50 = 0.48 microM), it was found that replacement by an Ala residue of Gla4 led to complete inactivation of the peptide, whereas a similar replacement of Gla3 resulted in a 20-fold decreased potency. Ala substitutions for Gla10 and Gla14 did not substantially affect [3H]MK-801 binding. This same substitution at Gla7 appeared to slightly enhance binding. Ala replacements of non-Gla residues demonstrated that four of them, viz. Glu2, Leu5, Gln9, and Ile12, possessed at least 200-fold decreases in inhibitory potency, whereas similar replacements at Gly1, Leu11, and Arg13 resulted in peptides with 8- to 12-fold increases in the IC50 values. The remaining amino acid residues tested in the single Ala replacement series showed no significant changes in the inhibitory characteristics of wild-type con-G. Additional studies with carboxyl-terminal truncated peptides revealed that the carboxyl-terminal 4 amino acids were unimportant for this activity. There was no strict correlation of inhibition of [3H]MK-801 binding with the ability of these peptides to form cation-dependent alpha-helices. Peptides with notably low alpha-helical content in the presence of these cations were lacking at least one, or both, of Gla10 and Gla14. Con-G[Gla3,4,7,10,14E] and con-G[Gla7,10,14E] were the only peptides that remained in a completely random conformation upon metal ion addition.     

Molecular modeling of immunoglobulin light chains implicates hydrophobic residues in non-amyloid light chain deposition disease

Light chain deposition disease is a severe complication of certain immunoproliferative disorders, due to the secretion of a monoclonal light chain which precipitates close to basement membranes of several tissues. A kappa isotype restriction and an unusual frequency of a variable region subgroup (VkappaIV) suggest that precise structural features govern the propensity of pathogenic light chains to precipitate in extracellular spaces. We studied primary structures of light chains from six patients with light chain deposition disease in comparison with light chains from other pathological conditions. Sequence alignment revealed the presence of certain amino acids only in light chain deposition disease, in particular non-polar replacing hydrophilic residues. To determine the role of these residues, structures of the variable domain from four kappa chains belonging to VkappaI and VkappaIV subgroups responsible for deposition disease were modeled using known immunoglobulins as templates. The most evident structural features shared by all pathogenic light chains were hydrophobic residues exposed to the solvent in complementarity determining regions 1 or 3. In contrast to immunoglobulin light chain- related amyloidosis, where deposition of organized material might be due to electrostatic interactions between light chain dimers, hydrophobic interactions could enhance amorphous precipitation in non- amyloid light chain deposition disease.