Effect of caffeine on simulator flight performance in sleep-deprived military pilot students

Caffeine has been suggested to act as a countermeasure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown under sleep deprivation. However, subjective evaluation of overall flight performance in the caffeine group tended to be too optimistic, indicating a potential flight safety problem. Based on our results, we do not recommend using caffeine pills in military flight operations.     

Accuracy of plain abdominal radiographs in the detection of retained surgical needles in the peritoneal cavity

OBJECTIVE: To determine the accuracy of plain abdominal radiographs in the detection of retained surgical needles of varying size in the peritoneal cavity. SUMMARY BACKGROUND DATA: Accidental retention of surgical foreign bodies in the peritoneal cavity is estimated to occur once in every 1000 to 1500 abdominal operations and early prevention and identification of retained foreign bodies is increasingly important because of mounting public awareness. Most of the existing literature on the imaging detection of surgical foreign bodies has focused on retained sponges, even though retained needles may account for up to 50% of such objects and the true accuracy of plain abdominal radiographs in the detection of retained needles is not well established. METHODS: Eight plain radiographs were obtained of a 41 kg pig cadaver after placement of a total of 39 surgical needles of varying size (4-77 mm in length) in a randomized selection of the 9 segments of the peritoneal cavity. Five radiologists independently reviewed the radiographs and indicated the location of all suspected retained needles. Analyses were performed using the known site and size of placed needles as the standard of reference. RESULTS: In total for all readers, 195 needles were detectable in 360 abdominal segments. The overall mean accuracy, sensitivity, and specificity for plain radiographs in the detection of retained surgical needles were 74% (267 of 360), 69% (135 of 195), and 80% (132 of 165), respectively. Sensitivity for needles 25 mm or more in length was significantly (P < 0.0001) higher than that for needles of 11 to 24 mm or 10 mm or less, with respective values of 99% (69 of 70), 84% (46 of 55), and 29% (20 of 70). Readers demonstrated moderate interobserver agreement, with a multireader kappa value of 0.60. CONCLUSIONS: Abdominal radiographs have high sensitivity and interobserver agreement in the detection of retained surgical needles over 10 mm in length, but smaller needles are detected with significantly lower sensitivity and the utility of plain abdominal radiographs in this setting is more debatable.     

Role of sonography in the recognition, assessment, and treatment of cesarean scar ectopic pregnancies.

OBJECTIVE: Cesarean scar ectopic pregnancies (CSEPs) are rare but may have serious adverse consequences and are therefore important to promptly recognize on sonography. We aim to describe the typical sonographic appearances. Potential treatments are discussed, including sonographic guidance for transcervical injection of methotrexate (MTX) into the gestational sac. METHODS: Two patients with CSEPs were treated with systemic and intra-amniotic administration of MTX under sonographic guidance. RESULTS: Both patients were followed clinically after medical treatment, resulting in low maternal morbidity and mortality. CONCLUSIONS: Considering the increasing rate of cesarean delivery and the increased risk of CSEPs, sonologists should be familiar with the sonographic appearances of a pregnancy implanted into the cesarean scar. We show how to correctly diagnose scar implantation and describe how to perform sonographically guided transcervical injection of MTX.     

Bone oedema predicts erosive progression on wrist MRI in early RA--a 2-yr observational MRI and NC scintigraphy study

OBJECTIVES: To investigate if disease assessment by contrast-enhanced dynamic and static magnetic resonance imaging (MRI) and quantitative nanocolloid (NC) scintigraphy gives useful additional information in early rheumatoid arthritis (RA). METHODS: Twenty-seven patients with early RA (disease duration < or =12 months) were followed up for 1 yr and 24 of them for 2 yrs with contrast-enhanced MRI and NC scintigraphy of the wrist joint. Synovial inflammation was assessed by measuring time-dependent enhancement rates (E-rate) from dynamic MRI scans and technetium(99m)-labelled nanocolloid ((99m)Tc-NC) uptake from scintigraphy scans. Synovial membrane hypertrophy, bone oedema and erosions were semiquantitatively scored according to the Outcome Measures in Rheumatology Clinical Trials RA-MRI scoring system from static MR images. Response to the treatment was evaluated based on whether or not > or = 50% improvement was achieved in the tender and swollen joint scores and the Health Assessment Questionnaire score, with normal C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) levels. Progression of the erosion score on wrist MRI was evaluated as the outcome. RESULTS: The baseline MRI bone oedema score (rho= 0.67), MRI synovitis score (rho= 0.57), ESR (rho= 0.56), CRP (rho= 0.48), E-rate (rho= 0.47) and (99m)Tc-NC uptake (rho= 0.45) were related with the change in the MRI erosion score from baseline to 2 yrs (rho= Spearman's correlation). In the multivariate logistic regression model, the bone marrow oedema score was the only baseline variable that predicted erosive progression at 2 yrs' follow-up (OR 4.2, 95% CI 1.3-13.8). The median (interquartile range) change in the erosion score from baseline to 2 yrs was 0 (0, 0) and 4 (2, 5) in the patients with (n= 9) and without (n= 15) a persistent clinical response over the 2 yrs, respectively (P= 0.001). The non-responders who presented with erosive progression from 1 yr to 2 yrs had higher MRI synovitis scores, bone oedema scores, E-rate and (99m)Tc-NC uptake at 1-yr follow-up than the non-responders without progressive bone damage. CONCLUSION: The degree of local synovial inflammation at baseline, evaluated by dynamic and static MRI and quantitative NC scintigraphy, is closely related to the progression of wrist joint erosions during the first 2 yrs of the disease. Furthermore, at follow-up, if no persistent clinical response is achieved, these imaging methods may help to predict future erosiveness and help in clinical therapeutic decision making.     

25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) induces ectopic calcification

Vascular calcification is an important pathogenesis related to cardiovascular disease and high mortality rate in chronic kidney disease (CKD) patients. It has been well-known that hyper­phosphatemia induces osteochondrogenic transition of vascular smooth muscle cells (VSMCs) resulting ectopic calcification in aortic media, cardiac valve, and kidney. However, the detailed mechanism of the ectopic calcification has been not clarified yet. Here, we found that the co-localization of CYP27B1 with the calcified lesions of aorta and arteries in kidney of klotho mutant (kl/kl) mice, and then investigated the role of CYP27B1 in the mineralization of the VSMCs. Under high phosphate condition, overexpression of CYP27B1 induced calcification and osteocalcin mRNA expression in the VSMCs. Inversely, siRNA-CYP27B1 inhibited high phosphate-induced calcification of the VSMCs. We also found that the accumulated CYP27B1 protein was glycosylated in the kidney of kl/kl mice. Therefore, overexpression of CYP27B1-N310A and CYP27B1-T439A, which are a mutation for N-linked glycosylation site (N310A) and a mutation for O-linked glycosylation site (T439A) in CYP27B1, decreased calcium deposition and expression of RUNX2 induced by high phosphate medium in VSMCs compared with wild-type CYP27B1. These results suggest that extra-renal expression of glycosylated CYP27B1 would be required for ectopic calcification of VSMCs under hyperphosphatemia.     

Pseudotumor of the distal common bile duct at endoscopic retrograde cholangiopancreatography

Background

Prior studies have described a pseudocalculus appearance in the distal common bile duct as a normal variant at cholangiography. The objective of this study was to describe the occurrence of pseudotumor in the distal common bile duct at endoscopic retrograde cholangiopancreatography (ERCP).

Methods

Nine patients who underwent ERCP between May 2004 and July 2008 were identified as having a transient eccentric mural-based filling defect in the distal common bile duct. A single reader systematically reviewed all studies and recorded the imaging findings.

Results

The mean diameter of the filling defect was 9 mm (range, 5 to 11). Eight patients had resolution of the filling defect during the same ERCP or on a subsequent ERCP, and in two of these patients the inferior border of the filling defect was not well visualized. The other patient underwent surgical resection of a presumed tumor with no evidence of malignancy on surgical pathology.

Conclusion

An eccentric mural-based filling defect in the distal common bile duct can be artifactual in nature and may reflect transient contraction of the sphincter of Oddi. Recognition of this pseudotumor may help avoid unnecessary surgery.     

Switching direction in electric-signal-induced cell migration by cyclic guanosine monophosphate and phosphatidylinositol signaling

Switching between attractive and repulsive migration in cell movement in response to extracellular guidance cues has been found in various cell types and is an important cellular function for translocation during cellular and developmental processes. Here we show that the preferential direction of migration during electrotaxis in Dictyostelium cells can be reversed by genetically modulating both guanylyl cyclases (GCases) and the cyclic guanosine monophosphate (cGMP)-binding protein C (GbpC) in combination with the inhibition of phosphatidylinositol-3-OH kinases (PI3Ks). The PI3K-dependent pathway is involved in cathode-directed migration under a direct-current electric field. The catalytic domains of soluble GCase (sGC) and GbpC also mediate cathode-directed signaling via cGMP, whereas the N-terminal domain of sGC mediates anode-directed signaling in conjunction with both the inhibition of PI3Ks and cGMP production. These observations provide an identification of the genes required for directional switching in electrotaxis and suggest that a parallel processing of electric signals, in which multiple-signaling pathways act to bias cell movement toward the cathode or anode, is used to determine the direction of migration.