Search

Table of Contents Background The Technique Discussion References Background Ligation and stripping of short saphenous vein (SSV) is commonly performed in the prone position under general anaesthesia.To perform ligation of [...]

Polymorphisms of the dopamine receptor D4 gene DRD4, 11p15.5, have previously been associated with attention‐deficit/hyperactivity disorder (ADHD) [Bobb et al., 2005; Am J Med Genet B Neuropsychiatr Genet 132:109–125; Faraone et al., 2005; Biol Psychiatry 57:1313–1323; Thapar et al., 2005; Hum Mol Genet 14 Spec No. 2:R275‐R282]. As a follow up to a pilot study [see Castellanos et al., 1998; Mol Psychiatry 3:431–434] consisting of 41 probands and 56 controls which found no significant association between the DRD4 7‐repeat allele in exon 3 and ADHD, a greatly expanded study sample (cases n = 166 and controls n = 282) and long term follow‐up (n = 107, baseline mean age n = 9, follow‐up mean age of n = 15) prompted reexamination of this gene. The DRD4 7‐repeat allele was significantly more frequent in ADHD cases than controls (OR = 1.2; P = 0.028). Further, within the ADHD group, the 7‐repeat allele was associated with better cognitive performance (measured by the WISC‐III) (P = 0.013–0.07) as well as a trend for association with better long‐term outcome. This provides further evidence of the role of the DRD4 7‐repeat allele in the etiology of ADHD and suggests that this allele may be associated with a more benign form of the disorder. © 2006 Wiley‐Liss, Inc.

We present data which show that the Escherichia coli integration host factor (IHF) is an activator of phage f1 DNA replication. Phage f1 poorly infects bacterial strains lacking IHF because IHF is required for efficient expression of F-pili, the receptor for f1 phage. However, when F- strains are transfected with f1 DNA the phage replicates in IHF mutants (himA, himD, or himA himD) at a rate of only 3% of that in wild-type bacteria. A plasmid dependent on the f1 replicon fails to transform IHF mutants. By gel retardation analysis, we show that IHF specifically binds to the origin of replication. DNase I "footprinting" experiments demonstrate that IHF binds to multiple sites within the replication enhancer sequence, a cis-acting, A + T-rich sequence that potentiates f1 DNA replication. Moreover, the effect of IHF mutation on f1 growth is suppressed by initiator protein (f1 gene II) mutations that restore efficient replication from origins that lack a functional replication enhancer sequence. This genetic evidence supports the conclusion that the replication enhancer sequence is the site of action of IHF.

Nuclei within myotubes do not synthesize DNA for replication. Accordingly, cultures of myotubes display low levels of DNA polymerase activity. The coincidental decline in DNA polymerase activity and increased formation of multinucleated myotubes during culture does not prove that the loss of capacity to synthesize DNA is a consequence of fusion. Tne experiments described demonstrate that myogenic cells prevented from fusing have low levels of DNA polymerase activity. This is consistent with the notion that, in myogenic cultures, there is a population of mononucleated cells, the myoblasts, which have withdrawn from the mitotic cycle before fusion.

The replication initiator protein (gene II protein (gpII)) of bacteriophage f 1 is a multifunctional protein that plays central roles in initiation and termination of phage DNA replication. It introduces a nick at a specific site on the (+)-strand of supercoiled replicative form DNA. The 3′-hydroxyl end of the nick serves as the primer for (+)-strand rolling-circle replication. Upon completion of a round of synthesis, gpII cleaves and circularizes the displaced single strand. When Mn2+is included in the buffer instead of Mg2+, gpII cleaves both strands. In this paper, we investigate the mechanism of the Mn2+-dependent double-strand cleavage activity of gpII. This reaction, unlike nicking in the presence of Mg2+, does not require superhelicity. The reaction proceeds in two kinetic steps: first nicking of the (+)-strand, and then cleavage of the (−)-strand. The nucleotide sequence requirement for nicking is reduced compared to that in the presence of Mg2+. The product of the double-strand cleavage has an unusual structure. The left end is a telomere-like hairpin since the (+)- and (−)-strands are joined, as demonstrated by base sequencing. The right end has a one-base 3′-overhang. This reaction probably reflects the cleavage-joining activity of gpII in the termination event.

In order to establish underlying mechanisms responsible for the vasospastic disorder vibration white finger (VWF), the acute effect of vibration on digital blood flow was assessed. Thirteen patients with primary Raynaud's phenomenon (RP), 15 patients with VWF and 13 controls were exposed to acute vibration in the middle digit of one hand for 1 and 3 minutes. Blood flow was measured in that digit and in the middle finger of the contralateral hand using strain gauge plethysmography before and after vibration. The measurements were then repeated following digital nerve blockade using 2% Lignocaine in the vibrated digit. The results demonstrate that vibration affects digital blood flow through two independent mechanisms. Vibration appears to cause both an axonal vasoconstrictor reflex and an active local vasodilation phenomenon. In patients with established vasospastic disorders this vasoconstrictor reflex is exaggerated.

Abstract: Objective assessment of chemical lumbar sympathectomy (CLS) is lackin.. Its success is usually judged in terms of the patient's clinical improvement. We have thermographically measured the immediate temperature changes of the lower limb following CLS using a thermal imager (SAN-EI Thermotracer 6T61). Seven patients with critical limb ischaemia and one patient with Raynaud's phenomenon underwent unilateral ablation of the lumbar sympathetic chain using 5% phenol. Four patients were diabetic, two of whom had undergone previous sympathectomy on the same side. Within fifteen minutes of injection, all patients showed a rise in skin temperature in parts of the sock distribution of between 0.8°C and 8.5°C. We conclude that the haemodynamic effects of CLS are immediate and can be objectively measured with thermal imaging.

Objective assessment of chemical lumbar sympathectomy (CLS) is lackin.. Its success is usually judged in terms of the patient's clinical improvement. We have thermographically measured the immediate temperature changes of the lower limb following CLS using a thermal imager (SAN-EI Thermotracer 6T61). Seven patients with critical limb ischaemia and one patient with Raynaud's phenomenon underwent unilateral ablation of the lumbar sympathetic chain using 5% phenol. Four patients were diabetic, two of whom had undergone previous sympathectomy on the same side. Within fifteen minutes of injection, all patients showed a rise in skin temperature in parts of the sock distribution of between 0.8°C and 8.5°C. We conclude that the haemodynamic effects of CLS are immediate and can be objectively measured with thermal imaging.