Biodiesel exhaust particle airway toxicity and the role of polycyclic aromatic hydrocarbons.

Renewable alternatives to fossil diesel (FD) including fatty acid methyl ester (FAME) biodiesel have become more prevalent. However, toxicity of exhaust material from their combustion, relative to the fuels they are displacing has not been fully characterised. This study was carried out to examine particle toxicity within the lung epithelium and the role for polycyclic aromatic hydrocarbons (PAHs). Exhaust particles from a 20% (v/v) blend of FAME biodiesel had little impact on primary airway epithelial toxicity compared to FD derived particles but did result in an altered profile of PAHs, including an increase in particle bound carcinogenic B[a]P. Higher blends of biodiesel had significantly increased levels of more carcinogenic PAHs, which was associated with a higher level of stress response gene expression including CYP1A1, NQO1 and IL1B. Removal of semi-volatile material from particulates abolished effects on airway cells. Particle size difference and toxic metals were discounted as causative for biological effects. Finally, combustion of a single component fuel (Methyl decanoate) containing the methyl ester molecular structure found in FAME mixtures, also produced more carcinogenic PAHs at the higher fuel blend levels. These results indicate the use of FAME biodiesel at higher blends may be associated with an increased particle associated carcinogenic and toxicity risk.

Tsetse GmmSRPN10 has anti-complement activity and is important for successful establishment of trypanosome infections in the fly midgut.

The complement cascade in mammalian blood can damage the alimentary tract of haematophagous arthropods. As such, these animals have evolved their own repertoire of complement-inactivating factors, which are inadvertently exploited by blood-borne pathogens to escape complement lysis. Unlike the bloodstream stages, the procyclic (insect) stage of Trypanosoma brucei is highly susceptible to complement killing, which is puzzling considering that a tsetse takes a bloodmeal every 2-4 days. In this study, we identified four tsetse (Glossina morsitans morsitans) serine protease inhibitors (serpins) from a midgut expressed sequence tag (EST) library (GmmSRPN3, GmmSRPN5, GmmSRPN9 and GmmSRPN10) and investigated their role in modulating the establishment of a T. brucei infection in the midgut. Although not having evolved in a common blood-feeding ancestor, all four serpins have an active site sharing remarkable homology with the human complement C1-inhibitor serpin, SerpinG1. RNAi knockdown of individual GmmSRPN9 and GmmSRPN10 genes resulted in a significant decreased rate of infection by procyclic form T. brucei. Furthermore, recombinant GmmSRPN10 was both able to inhibit the activity of human complement-cascade serine proteases, C1s and Factor D, and to protect the in vitro killing of procyclic trypanosomes when incubated with complement-activated human serum. Thus, the secretion of serpins, which may be part of a bloodmeal complement inactivation system in tsetse, is used by procyclic trypanosomes to evade an influx of fresh trypanolytic complement with each bloodmeal. This highlights another facet of the complicated relationship between T. brucei and its tsetse vector, where the parasite takes advantage of tsetse physiology to further its chances of propagation and transmission.

Are fluoroscopic caudal epidural steroid injections effective for managing chronic low back pain?

OBJECTIVE: This study sought to determine the efficacy of fluoroscopic caudal epidural steroid injections as a conservative treatment in patients with presumably chronic lumbar discogenic pain. SUMMARY OF BACKGROUND DATA: Epidural steroid injections have been used in the treatment of lumbar radicular pain with success. However, despite their widespread use, there are few, if any, reports of the efficacy of Epidural steroid injections in patients with predominantly axial lumbar pain. Prior studies have been limited by the use of non-fluoroscopically guided injections and failing to apply a specific injection approach (i.e. transforaminal, interlaminar, or caudal) to a specific patient population. METHODS: Ninety-seven patients with chronic axial low back pain and Magnetic Resonance Imaging evidence of disc pathology without stenosis were selected from chart review. All patients received at least one fluoroscopically guided caudal epidural injection with 12 mg of betamethasone and 8 cc of 0.5% lidocaine. Collected follow-up information included Roland-Morris Disability, Visual Numeric Pain Scale, and patient satisfaction scores. RESULTS: Only nineteen patients (23%) were determined to have a successful long- term (> 1 year) outcome and 65 (77%) were deemed failures. Average follow-up was 28.6 +/- 15.6 months. Successes were found to differ significantly from failures in pre-injection pain scores and patient satisfaction. Overall patient satisfaction was 45%. CONCLUSION: At greater than two year follow-up, the efficacy of fluoroscopically guided caudal epidural steroid injections in patients with chronic lumbar discogenic pain is poor. Patient satisfaction exceeds the reported rate of efficacy. Patients responding to injection have significantly lower pre-injection pain scores.

Fluoroscopically guided caudal epidural steroid injections for lumbar spinal stenosis: a restrospective evaluation of long term efficacy.

BACKGROUND: Degenerative lumbar spinal stenosis is a frequent cause of disability in the elderly population. Epidural steroid injections are a commonly used conservative modality in the treatment of patients with degenerative lumbar spinal stenosis. Relatively few studies have specifically addressed the efficacy of epidural steroid injections for spinal stenosis, with success rates varying from 20% to 100%. OBJECTIVE: To assess the efficacy of fluoroscopically guided caudal epidural steroid injections in the management of degenerative lumbar spinal stenosis. DESIGN: Retrospective chart review and follow-up study. METHODS: All the patients who had undergone at least one fluoroscopically guided caudal epidural steroid injection between 1995 and 2002 were reviewed. All of the caudal epidural steroid injections were done with fluoroscopic guidance. MAIN OUTCOME MEASURES: Visual Numeric Scale (VNS), Roland-Morris Disability Questionnaire (RMDQ), North American Spine Society Patient Satisfaction Index (NASS), and subsequent surgery. RESULTS: Ninety-five patients selected from chart review met inclusion criteria. Eighty (84%) completed the follow-up questionnaire by mail or telephone interview. Patients received an average of 1.6 epidural steroid injections. Twelve patients subsequently underwent surgical procedures. A VNS improvement of 50% or greater was seen in 35% of patients. A functional improvement of 2 points or greater was seen on the RMDQ in 36% of patients. Long-term success of treatment was seen in 35% of patients. The concurrent presence of degenerative spondylolisthesis was the only variable which was found to have a significant positive correlation with successful outcomes (P < 0.009). CONCLUSION: Caudally placed fluoroscopically guided epidural steroid injections offered a safe, minimally invasive option for managing pain caused by lumbar spinal stenosis. The concurrent presence of degenerative spondylolisthesis appears to be an independent positive prognostic factor for successful outcome.

Histological and molecular structure characterization of annular collagen after intradiskal electrothermal annuloplasty.

The mechanism of pain relief of intradiskal electrothermal annuloplasty (IDET) in the treatment of lumbar diskogenic pain is uncertain. Theories include sealing of annular fissures via collagen denaturation and contraction. Prior studies offer conflicting qualitative data on the ability of IDET to denature collagen. The objective of the present study is to evaluate IDET treatment effect on annular collagen using quantitative data supplied by Fourier-transform infrared imaging spectroscopy. The posterior annulus of disks (n = 3) from an intact human cadaveric spine at room temperature were treated with two different radiothermal catheters using standard intradiskal electrothermal annuloplasty (IDET) heating protocols. Disks were dissected free with catheters in place and fixed in formalin. Channels created by the catheters were marked and catheters were removed. Tissue samples of treated areas adjacent to the channels and internal control areas from the same disk were stained for light microscopy and placed on barium sulfate windows for Fourier transform infrared imaging spectroscopy (FT-IRIS) analysis. Treated areas showed evidence of disruption in the fibrillar organization of annular collagen by light microscopy compared to intact stroma from control areas. Quantitative FT-IRIS analysis compared ratios of wavenumber regions known to be sensitive to collagen denaturation. Mean values for the ratios amide II/1,338 cm(-1) (137.21 +/- 25.84 treated, 76.94 +/- 16.77 control) and 1,640/1,660 cm(-1) (0.98 +/- 0.03 treated, 0.89 +/- 0.03 control) were significantly different between treated and control samples (p < 0.001), indicating a breakdown in collagen integrity. Separate analysis by catheter type suggests that catheter design may impact treatment effect.

Prevalence of peripheral neurologic injuries in rotator cuff tears with atrophy.

The purpose of this study is to define the prevalence of peripheral nerve injury associated with full-thickness tears of the rotator cuff presenting with shoulder muscle atrophy. Twenty-five patients with the diagnosis of full-thickness rotator cuff tear were included. Electrodiagnostic testing, including nerve conduction studies and needle examination, was performed on all patients. There were 7 abnormal electromyographic examinations. The most common diagnosis was upper trunk brachial plexopathy severely affecting the axillary nerve (4/7), followed by suprascapular neuropathy (2/7) and cervical radiculopathy (1/7). The prevalence of associated peripheral neuropathy was found to be 28%. Greater degrees of atrophy were significantly associated with the presence of neuropathy in these patients. Careful neurologic screening in all patients and electromyographic examination in clinically suspicious groups are recommended in patients with full-thickness cuff tears before surgical repair.