Nitrate administration increases blood flow in dysfunctional but viable myocardium, leading to improved assessment of myocardial viability: A PET study.

SPECT with 99mTc-labeled agents is better able to detect viability after nitrate administration. Nitrates induce vasodilation and may increase blood flow to severely hypoperfused but viable myocardium, thereby enhancing tracer delivery and improving the detection of viability. Quantitative data on the changes in blood flow are lacking in SPECT but can be provided by PET. The aim of the present study was to use PET to evaluate whether nitrate administration increases blood flow to chronically dysfunctional but viable myocardium. METHODS: 13N-Ammonia PET was used to quantitatively assess blood flow, and 18F-FDG PET was used as the gold standard to detect viable myocardium. Twenty-five patients with chronic ischemic left ventricular dysfunction underwent 13N-ammonia PET at rest and after nitrate administration. RESULTS: A significant increase in nitrate-enhanced blood flow was observed in viable segments (from 0.55 +/- 0.15 to 0.68 +/- 0.24 mL/min/g, P < 0.05). No statistically significant change in blood flow was observed in nonviable segments (0.60 +/- 0.20 vs. 0.55 +/- 0.18 mL/min/g). A ratio of at least 1.1 for nitrate-enhanced flow to resting flow allowed optimal detection of viable myocardium, yielding a sensitivity of 82% with a specificity of 100%. CONCLUSION: 13N-Ammonia PET showed a significant increase in nitrate-enhanced blood flow in viable myocardium, whereas blood flow remained unchanged after nitrate administration in nonviable myocardium. Nitrate use during myocardial perfusion imaging will lead to improved assessment of myocardial viability.     

Fast CT-PRESS-based spiral chemical shift imaging at 3 Tesla.

A new sequence is presented that combines constant-time point-resolved spectroscopy (CT-PRESS) with fast spiral chemical shift imaging. It allows the acquisition of multivoxel spectra without line splitting with a minimum total measurement time of less than 5 min for a field of view of 24 cm and a nominal 1.5x1.5-cm2 in-plane resolution. Measurements were performed with 17 CS encoding steps in t1 (Deltat1=12.8 ms) and an average echo time of 151 ms, which was determined by simulating the CT-PRESS experiment for the spin systems of glutamate (Glu) and myo-inositol (mI). Signals from N-acetyl-aspartate, total creatine, choline-containing compounds (Cho), Glu, and mI were detected in a healthy volunteer with no or only minor baseline distortions within 14 min on a 3 T MR scanner.     

Treatment of nasopharyngeal stenosis by prosthetic hollow stents: Clinical experience in eight patients.

OBJECTIVE: A series of nasopharyngeal appliance designs is presented that represents our evolving experience over a 20-year period in the adjunctive use of prosthetic stents in the surgical correction of nasopharyngeal stenosis. DESIGN: Retrospective assessment of effectiveness of two nasopharyngeal stenosis hollow stent designs in a consecutive series of patients for relief of nasal obstructive symptoms. SETTING: Tertiary academic medical center, Craniofacial Program at Children's Hospital. PATIENTS: Four patients with nasopharyngeal stenosis were treated with a preoperatively fabricated stent made from a clasped palatal appliance onto which hollow acrylic conduits were extended through surgically re-created pharyngeal ports. A subsequent set of four patients with nasopharyngeal stenosis were treated with intraoperatively-fashioned silastic grommets, as opposed to palatal appliances. INTERVENTIONS: Postoperative intraoral stenting of nasopharyngeal ports. MAIN OUTCOME MEASURES: Maintenance of pharyngeal port opening after 1 year, improvement in nasal airway obstructive symptoms. RESULTS: The palatal appliance stents were less well tolerated and had a lower maintenance of port patency after device removal (4 of 8, 50%). The silastic grommets provided better retention into the ports and increased patient tolerance, as well as better 1-year port maintenance (6 of 8, 75%). CONCLUSIONS: The grommet stent appliance offers numerous advantages over a conventional dental-clasped appliance for prosthetic nasopharyngeal stenting, including obviation of extensive preoperative preparation, ease of insertion and removal, and exchange of air during the stenting period. Improved nasopharyngeal patency with this device may be due to greater patient tolerance and subsequent longer use.     

Is there a diurnal pattern in the clinical symptoms of HELLP syndrome?

OBJECTIVE: To determine if there is a diurnal pattern in the clinical symptoms of HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. STUDY DESIGN: A retrospective study was performed in 134 pregnancies complicated by HELLP syndrome. The medical records were reviewed to describe each HELLP episode. Time of day was divided into three periods, day, evening, and night. The following parameters were categorized according to the time of day: onset of symptoms, consultation by the doctor, initial blood sampling, diagnosis and decrease of symptoms. Biochemical parameters at clinical presentation and consecutive changes within 24 h were recorded. RESULTS: In 65 pregnancies 77 HELLP episodes were well documented. Times of onset of symptoms and consultation by the doctor were significantly higher during the evening and night (p < 0.001), whereas times of diagnosis and decrease of symptoms occurred significantly more during the day (p < 0.001). In only 49.3% of the cases were diagnostic laboratory criteria met at clinical presentation. This was mainly due to platelet values in excess of 100 x 10(9)/l. Several hours later (median 8 h, range 2-23) the decrease in platelets occurred. CONCLUSIONS: A diurnal pattern exists in the clinical symptoms of HELLP syndrome that is characterized by an exacerbation during the night and recovery during the day. There is a considerable delay between the onset of symptoms and the fulfillment of diagnostic laboratory criteria.     

Strategies to enhance transductional efficiency of adenoviral-based gene transfer to primary human fibroblasts and keratinocytes as a platform in dermal wounds

Genetically modified keratinocytes and fibroblasts are suitable for delivery of therapeutic genes capable of modifying the wound healing process. However, efficient gene delivery is a prerequisite for successful gene therapy of wounds. Whereas adenoviral vectors (Ads) exhibit superior levels of in vivo gene transfer, their transductional efficiency to cells resident within wounds may nonetheless be suboptimal, due to deficiency of the primary adenovirus receptor, coxsackie-adenovirus receptor (CAR). We explored CAR-independent transduction to fibroblasts and keratinocytes using a panel of CAR-independent fiber-modified Ads to determine enhancement of infectivity. These fiber-modified adenoviral vectors included Ad 3 knob (Ad5/3), canine Ad serotype 2 knob (Ad5CAV-2), RGD (Ad5.RGD), polylysine (Ad5.pK7), or both RGD and polylysine (Ad5.RGD.pK7). To evaluate whether transduction efficiencies of the fiber-modified adenoviral vectors correlated with the expression of their putative receptors on keratinocytes and fibroblasts, we analyzed the mRNA levels of CAR, alpha upsilon integrin, syndecan-1, and glypican-1 using quantitative polymerase chain reaction. Analysis of luciferase and green fluorescent protein transgene expression showed superior transduction efficiency of Ad5.pK7 in keratinocytes and Ad5.RGD.pK7 in fibroblasts. mRNA expression of alpha upsilon integrin, syndecan-1 and glypican-1 was significantly higher in primary fibroblasts than CAR. In keratinocytes, syndecan-1 expression was significantly higher than all the other receptors tested. Significant infectivity enhancement was achieved in keratinocytes and fibroblasts using fiber-modified adenoviral vectors. These strategies to enhance infectivity may help to achieve higher clinical efficacy of wound gene therapy.     

Statins are associated with a reduced infrarenal abdominal aortic aneurysm growth.

OBJECTIVE: To evaluate the effect of statins on aneurysm growth in a group of consecutive patients under surveillance for infrarenal aortic aneurysms (AAA). MATERIALS AND METHODS: All patients (59 statin users, 91 non-users) under surveillance between January 2002 and August 2005 with a follow-up for aneurysm growth of at least 12 months and a minimum of three diameter evaluations were retrospectively included in the analysis. Multiple regression analysis, weighted with the number of observations, was performed to test the influence of statins on AAA growth rate. RESULTS: During a median period of 3.1 (1.1-13.1) years the overall mean aneurysm growth rate was 2.95+/-2.8 mm/year. Statin users had a 1.16 mm/year lower AAA growth rate compared to non-users (95% CI 0.33-1.99 mm/year). Increased age was associated with a slower growth (-0.09 mm/year per year, p = 0.003). Female gender (+1.82 mm/year, p = 0.008) and aneurysm diameter (+0.06 mm/year per mm, p = 0.049) were associated with increased AAA growth. The use of non-steroidal anti-inflammatory drugs, chronic lung disease, or other cardiovascular risk factors were not independently associated with AAA growth. CONCLUSIONS: Statins appear to be associated with attenuation of AAA growth, irrespective of other known factors influencing aneurysm growth.     

The value of a pantaloon cast test in surgical decision making for chronic low back pain patients: a systematic review of the literature supplemented with a prospective cohort study

The results of lumbar fusion in chronic low back pain (LBP) patients vary considerably, and there is a need for proper patient selection. Lumbosacral orthoses have been widely used to predict outcome, however, with little scientific support. The aim of the present study was to determine the value of a pantaloon cast test in selecting chronic LBP patients for lumbar fusion or conservative management. First, a systematic review of the literature was carried out in which two independent reviewers identified studies in Medline, Cochrane and Current Contents databases. Three papers met the selection criteria. In the only study with a control group, a significantly better outcome after fusion compared to conservative treatment was found in patients who reported significant pain relief while in a cast (i.e. a positive cast test). The results of lumbar fusion, however, were not significantly different for patients with a positive and those with a negative cast test. In addition to the review, a clinical cohort study of 257 LBP patients, who had been allocated to either lumbar fusion or conservative management by a temporary external transpedicular fixation trial, was performed. Prior to allocation, all had undergone a pantaloon cast test. Patients with no history of prior spine surgery and with a positive pantaloon cast test had a better outcome after lumbar fusion than those treated conservatively (P = 0.002, χ ² test). In patients with previous spine operations the outcomes were poor and the test was of no value. From the literature and the present patient cohort, it was concluded that only in chronic LBP patients without prior spine surgery, a pantaloon cast test with substantial pain relief suggests a favorable outcome of lumbar fusion compared to conservative management. The test has no value in patients who have had previous spine surgery.