Pulsed Radiofrequency Application in the Treatment of Chronic Pain

Abstract:   The efficacy of pulsed radiofrequency (PRF) in the treatment of painful lumbosacral spondylosis has been reported. This case series reviews 22 consecutive patients presenting to clinic who had been previously treated with PRF with good results. Patients being prescribed opioids were excluded. During the PRF application, tissue temperature was limited to 43°C. A minimum of 200 mA of current was delivered in each case. The minimum current (at 50 Hz) necessary to stimulate the involved nerve was recorded. The duration of time from PRF treatment until the patient requested a subsequent application was documented. The effective duration of PRF in patients treated for lumbosacral spondylosis ranged from 5 to 18 months (mean ± SD: 9 ± 3.7 months; n  = 16). PRF applications to dorsal root ganglia were effective from 2 to 12 months (7 ± 3.8 months; n  = 8). Similar results were observed when PRF was applied to cervical medial branch nerves, one suprascapular nerve, and one stellate ganglion. The mean (50 Hz) sensory stimulation thresholds obtained before treatment ranged from 0.08 V to 0.14 V. In this select population of patients not receiving controlled substances, who had a favorable response to a previous PRF application, the duration of pain relief supports the use of PRF as an effective pain treatment.     

Sleep disordered breathing in chronic stroke survivors. A study of the long term follow-up of the SCOPES cohort using home based polysomnography.

Prevalence of sleep-disordered breathing (SDB) (apnea-hypopnea index [AHI] > or = 5) in acute stroke patients ranges between 44% and 95%, compared to the community prevalence, 9 to 35% for women and 8 to 57% for men [age range 30-60 years]. Limited data exists beyond 3 months following stroke. We assessed the prevalence of SDB amongst stroke survivors at 3 years and compared results to data reported in normal and elderly populations. 90/143 eligible stroke survivors from an existing cohort underwent a home based sleep study. Mean age of the 78 subjects with a valid sleep study was 64 years (SD 15). Prevalence of SDB (AHI > or = 5) was 81% (95% CI 72% to 90%) and sleep apnoea syndrome (AHI > or = 5 plus ESS score > or =11) was 20% (95% CI 11% to 29%). Important predictors for AHI > or = 15 were haemorrhagic stroke (aOR12.06 [1.42-102.74]) and stroke severity at 1 month (aOR4.15 [1.05-16.38]). Large case-control studies are needed.     

Isolation and characterization of rad51 orthologs from Coprinus cinereus and Lycopersicon esculentum, and phylogenetic analysis of eukaryotic recA homologs

In eubacteria, the recA gene has long been recognized as essential for homologous recombination and DNA repair. Recent work has identified recA homologs in archaebacteria and eukaryotes, thus emphasizing the universal role this gene plays in DNA metabolism. We have isolated and characterized two new recA homologs, one from the basidiomycete Coprinus cinereus and the other from the angiosperm Lycopersicon esculentum. Like the RAD51 gene of Saccharomyces cerevisiae, the Coprinus gene is highly induced by gamma irradiation and during meiosis. Phylogenetic analyses of eukarotic recA homologs reveal a gene duplication early in eukaryotic evolution which gave rise to two putatively monophyletic groups of recA-like genes. One group of 11 characterized genes, designated the rad51 group, is orthologous to the Saccharomyces RAD51 gene and also contains the Coprinus and Lycopersicon genes. The other group of seven genes, designated the dmc1 group, is orthologous to the Saccharomyces DMC1 gene. Sequence comparisons and phylogenetic analysis reveal extensive lineage- and gene-specific differences in rates of RecA protein evolution. Dmc1 consistently evolves faster than Rad51, and fungal proteins of both types, especially those of Saccharomyces, change rapidly, particularly in comparison to the slowly evolving vertebrate proteins. The Drosophila Rad51 protein has undergone remarkably rapid sequence divergence. Received: 20 July / 25 October 1996     

Hydrophilic and Amphiphilic Forms of Drosophila Choline Acetyltransferase are Encoded by a Single mRNA

We have previously shown that the enzyme choline- O -acetyltransferase (ChAT) exists in a hydrophilic and an amphiphilic form in Drosophila head. A complementary DNA clone of 4.2 kb containing the entire coding region of ChAT was isolated from a cDNA library of Drosophila heads. The cDNA was subcloned in an expression vector and injected into the nucleus of Xenopus oocytes. Injected oocytes expressed high levels of ChAT activity. This activity was inhibited by bromoacetylcholine, a specific inhibitor of the enzyme. In the present study the non-ionic detergent Triton X-114 was used to analyse whether the expression of hydrophilic and amphiphilic ChAT was or was not directed by a single cDNA. The two forms of ChAT were found to be synthesized in injected oocytes. Approximately 9% of the recombinant enzyme partitioned as amphiphilic activity. This value was similar to that found for native amphiphilic ChAT in Drosophila heads. Sedimentation in sucrose gradients of amphiphilic enzyme was found to be influenced by the type of detergent present in the gradient whereas this was not the case for hydrophilic ChAT. Hydrophilic and amphiphilic enzyme activities differed in some of their biochemical properties. Amphiphilic ChAT was less sensitive to inhibition by the product acetylcholine than was hydrophilic ChAT. Moreover, amphiphilic ChAT was found to be more resistant than hydrophilic ChAT to heat inactivation at 45°C. These properties were observed for the native as well as for recombinant ChAT. These results demonstrate that the hydrophilic and amphiphilic forms of ChAT are derived from one mRNA.     

Access to commercial indoor tanning facilities by adults with highly sensitive skin and by under-age youth: compliance tests at solarium centres in Melbourne, Australia.

The study aimed to establish solarium operators' compliance with a newly revised voluntary code for the industry in 2002. The revisions incorporate guidelines to ensure customers are adequately informed of the risks associated with solarium use and that access by high-risk groups, such as customers with fair skin that does not tan (skin type 1) or those less than 18 years of age, is limited or barred. Compliance tests with the industry standard were conducted at 30 solarium centres in Melbourne, Australia. Compliance was tested by surveys and in-person visits from three research assistants, each presenting as potential customers but with different eligibility to attend a sunbed session: young adults eligible to attend a solarium, young adults with skin type 1 and under-age (16 year old) customers. This is the first study to assess solarium compliance using confederates with customer profiles that correspond to the required restrictions on sunbed access. Results showed poor compliance with specific aspects of the voluntary code. Fifty-two per cent of centres gave the underage teenagers access to sunbeds without written parental consent. Ninety per cent of centres provided sunbed access to clients with poor tanning ability and 75% of centres tried to reassure them about using the sunbeds. Seven per cent of centres did not provide any form of eye protection for customers and 7% provided sub-standard stickers for eye protection. The study suggests that there is much room for improvement in solarium centres' current practices and further regulation may well be warranted.     

Foot orthoses and physiotherapy in the treatment of patellofemoral pain syndrome: A randomised clinical trial

Background  

Patellofemoral pain syndrome is a highly prevalent musculoskeletal overuse condition that has a significant impact on participation in daily and physical activities. A recent systematic review highlighted the lack of high quality evidence from randomised controlled trials for the conservative management of patellofemoral pain syndrome. Although foot orthoses are a commonly used intervention for patellofemoral pain syndrome, only two pilot studies with short term follow up have been conducted into their clinical efficacy.