5-Hydroxy-L-[beta-11C]tryptophan versus alpha-[11C]methyl-L-tryptophan for positron emission tomography imaging of serotonin synthesis capacity in the rhesus monkey brain.

The purpose of this study was to compare two positron emission tomography (PET) tracers that were developed to follow serotonin (5HT) synthesis by performing sequential PET scanning of the same rhesus monkey (n=4) on the same day. alpha-[11C]Methyl-L-tryptophan ([11C]AMT) and 5-Hydroxy-L-[beta-11C]tryptophan ([11C]HTP) are substrates in the first and second enzymatic steps, respectively, in the biosynthesis of 5HT. Regional net accumulation rate constants were derived from kinetic (two-tissue compartment model with irreversible tracer trapping) and graphic (Patlak) analyses, using the arterial plasma concentrations as input. The kinetic data analysis showed that the rate constant for the transfer of [11C]HTP into the brain (K1) was higher than that for [11C]AMT in the striatum and thalamus but was similar in other brain regions. The rate constant for tracer trapping (k3) was also higher for [11C]HTP than for [11C]AMT in the striatum (0.046+/-0.024 versus 0.019+/-0.006 min(-1)) and thalamus (0.039+/-0.013 versus 0.016+/-0.007 min(-1)). In agreement with previously reported regional HTP accumulation rates, the net accumulation rate constant (K(acc)) for [11C]HTP was also higher in these regions than in other brain regions; this is in contrast to the uniform distribution of [11C]AMT K(acc) values. This suggests that the regional net accumulation rates obtained with these two PET tracers will be of different magnitude, which might be related to the activity of each targeted enzyme.     

Sole radiographic expression of rheumatoid arthritis in the temporomandibular joints: a case report.

We present an unusual case of rheumatoid arthritis. The patient had no radiographic findings in any joints of the body expected to show symptoms of the disease, such as phalangophalangeal joints of the hands and metacarpophalangeal joints. Instead, the patient had radiographic findings in the temporomandibular joints, which are not commonly involved in the disease and its activity.     

A survey of postoperative epidural and intravenous analgesia in Greece

BACKGROUND AND OBJECTIVE: Epidural and intravenous analgesia are widely used for postoperative pain management. Efficacy and safety is enhanced with the establishment of acute pain services. We studied the terms of application of these techniques in Greek hospitals and compared practices between anaesthetic departments with or without acute pain services. METHODS: We performed a postal survey regarding departmental policy on the application of epidural and intravenous analgesia, patient monitoring, audit and educational activities, acute pain service teams and proposals for improvement. Pain services were classified according to predetermined quality criteria. Hospitals with or without acute pain services were compared. RESULTS: Response rate was 46.3% (51 of 110 departments). Epidural analgesia was used in 49 departments, equally applied as intermittent boluses or continuous infusion. Twenty-two of the 39 departments that were using continuous infusion, used exclusively a lumbar approach. Intravenous analgesia was used by 42 (82%) departments; 13 used exclusively continuous infusion. All eight departments that had an established acute pain service fulfilled the predefined quality criteria compared with only ten of the remaining 43 (P < 0.001). CONCLUSION: Our study discloses important issues regarding the use of intravenous and epidural analgesia and postoperative patient monitoring in Greek hospitals. Implementation of acute pain services that are satisfying the quality criteria may help to improve patient care.     

SLC26A9-mediated chloride secretion prevents mucus obstruction in airway inflammation

Asthma is a chronic condition with unknown pathogenesis, and recent evidence suggests that enhanced airway epithelial chloride (Cl^–) secretion plays a role in the disease. However, the molecular mechanism underlying Cl^– secretion and its relevance in asthma pathophysiology remain unknown. To determine the role of the solute carrier family 26, member 9 (SLC26A9) Cl^– channel in asthma, we induced Th2-mediated inflammation via IL-13 treatment in wild-type and Slc26a9-deficient mice and compared the effects on airway ion transport, morphology, and mucus content. We found that IL-13 treatment increased Cl^– secretion in the airways of wild-type but not Slc26a9-deficient mice. While IL-13–induced mucus overproduction was similar in both strains, treated Slc26a9-deficient mice exhibited airway mucus obstruction, which did not occur in wild-type controls. In a study involving healthy children and asthmatics, a polymorphism in the 3′ UTR of SLC26A9 that reduced protein expression in vitro was associated with asthma. Our data demonstrate that the SLC26A9 Cl^– channel is activated in airway inflammation and suggest that SLC26A9-mediated Cl^– secretion is essential for preventing airway obstruction in allergic airway disease. These results indicate that SLC26A9 may serve as a therapeutic target for airway diseases associated with mucus plugging.     

The effect of hyperhomocysteinemia on aortic distensibility in healthy individuals

ObjectiveElevated plasma homocysteine (HCY) levels have been associated with increased risk for cardiovascular disease. Aortic distensibility and aortic pulse wave velocity (PWV) are indices of aortic elasticity. The potential effect of acute hyperhomocysteinemia (HHCY) on the elastic properties of the aorta in healthy individuals is not known. The aim of the present study was to determine the effect of acute methionine-induced HHCY on aortic distensibility and PWV in healthy individualsand the effect of acute HHCY on myocardial performance of the left ventricle (Tei index).MethodsThirty healthy volunteers were included in this crossover study. An oral methionine (100 mg/kg) or water load was given in random order on separate days at weekly intervals. Aortic distensibility and Tei index were determined non-invasively by ultrasonography at baseline and 3 h after methionine or water consumption, while PWV was measured by applanation tonometry at baseline and every 1 h for the same time interval.ResultsOral methionine induced an increase in total plasma HCY concentrations (P < 0.001), whereas HCY concentrations did not change after water consumption. Aortic distensibility decreased 3 h after methionine load (P < 0.001) and Tei index increased (P < 0.001), suggesting worsening compared with baseline values. Water consumption had no effect on aortic distensibility or Tei index values. PWV values did not change after either methionine or water consumption.ConclusionsAcute methionine-induced HHCY reduces aortic distensibility and worsens myocardial performance in healthy individuals. Further research is warranted to examine in the long term the direct effects of HHCY on cardiovascular function and the indirect effects on structural remodeling.