The temperature-size rule in Daphnia magna across different genetic lines and ontogenetic stages: Multiple patterns and mechanisms.

Ectotherms tend to grow faster, but reach a smaller size when reared under warmer conditions. This temperature-size rule (TSR) is a widespread phenomenon. Despite the generality of this pattern, no general explanation has been found. We therefore tested the relative importance of two proposed mechanisms for the TSR: (1) a stronger increase in development rate relative to growth rate at higher temperatures, which would cause a smaller size at maturity, and (2) resource limitation placing stronger constraints on growth in large individuals at higher temperatures, which would cause problems with attaining a large size in warm conditions. We raised Daphnia magna at eight temperatures to assess their size at maturity, asymptotic size, and size of their offspring. We used three clonal lines that differed in asymptotic size and growth rate. A resource allocation model was developed and fitted to our empirical data to explore the effect of both mechanisms for the TSR. The genetic lines of D. magna showed different temperature dependence of growth and development rates resulting in different responses for size at maturity. Also, at warm temperatures, growth was constrained in large, but not in small individuals. The resource allocation model could fit these empirical data well. Based on our empirical results and model explorations, the TSR of D. magna at maturity is best explained by a stronger increase in development rate relative to growth rate at high temperature, and the TSR at asymptotic size is best explained by a size-dependent and temperature-dependent constraint on growth, although resource limitation could also affect size at maturity. In conclusion, the TSR can take different forms for offspring size, size at maturity, and asymptotic size and each form can arise from its own mechanism, which could be an essential step toward finding a solution to this century-old puzzle.

Radiologist experience and CT examination quality determine metastasis detection in patients with esophageal or gastric cardia cancer.

We aimed to separate the influence of radiologist experience from that of CT quality in the evaluation of CT examinations of patients with esophageal or gastric cardia cancer. Two radiologists from referral centers ('expert radiologists') and six radiologists from regional non-referral centers ('non-expert radiologists') performed 240 evaluations of 72 CT examinations of patients diagnosed with esophageal or gastric cardia cancer between 1994 and 2003. We used conditional logistic regression analysis to calculate odds ratios (OR) for the likelihood of a correct diagnosis. Expert radiologists made a correct diagnosis of the presence or absence of distant metastases according to the gold standard almost three times more frequently (OR 2.9; 95% CI 1.4-6.3) than non-expert radiologists. For the subgroup of CT examinations showing distant metastases, a statistically significant correlation (OR 3.5; 95% CI 1.4-9.1) was found between CT quality as judged by the radiologists and a correct diagnosis. Both radiologist experience and quality of the CT examination play a role in the detection of distant metastases in esophageal or gastric cardia cancer patients. Therefore, we suggest that staging procedures for esophageal and gastric cardia cancer should preferably be performed in centers with technically advanced equipment and experienced radiologists.

Long-term results of primary stent placement to treat infrarenal aortic stenosis.

OBJECTIVE: To determine the safety and the long-term results of primary stent placement for localized distal aortic occlusive disease. DESIGN: Retrospective observational study. PATIENTS AND METHODS: From July 1998 to July 2005 17 patients (14 female and 3 men, mean age 57 years (39-80)) were treated for intermittent claudication. Five of these patients underwent additional endovascular treatment of focal iliac lesions. RESULTS: Technical success defined as residual stenosis of less than 50% or a trans-stenotic systolic pressure gradient <10% was achieved in 14 of 17 (82%) patients. Major complications included dissection at the puncture site in one patient and thrombosis of additional iliac stents in another patient. Both of these complications were successfully treated. During a mean follow-up of 27 months (range 1-86), four patients had recurrence of symptoms due to in-stent restenoses (n=2), femoral (n=1) or iliac occlusion (n=1), respectively. By Kaplan-Meier analysis, primary aortic hemodynamic patency was 83% at 3 years. Secondary aortic hemodynamic patency was 100%. The primary clinical patency was 68% at 3 years. CONCLUSION: Primary stent placement for distal aortic stenoses is an alternative to surgical treatment because of its high patency and relatively low complication rates.

Pelvic phleboliths: is there an association with diverticulitis?

Pelvic phleboliths are familiar structures to radiologists although their pathogenesis is not fully understood. The literature suggests a relationship between the prevalence of phleboliths and diverticular disease, and with a low-fibre diet. Phleboliths are said to be seen more frequently in women and on the left side in the pelvis. Their number seems to increase with advancing age. We have attempted to establish relations of phleboliths with diverticulitis, diverticulosis, sex, age and pelvic location. In this study the only statistically significant relation was an increase of the number of phleboliths with advancing age.

In vivo experiments with powder charcoal haemoperfusion (filmadsorber) in a pig model of hepatic failure.

The filmadsorber, an experimental haemoperfusion column containing activated powder charcoal embedded in a colloidal film, has been tested in pigs with ischaemicnecrosis of the liver. Haemoperfusion with a flow of 200 ml/min was performed for a duration of 4 to 6 hours. Bile acid clearances varied between +/- 52 ml/min (1st hour) and +/- 23 ml/min (6th hour). Clearances for aromatic amino acids were initially even higher (phenylalanine 115, tyrosine 112 and methionine 46 ml/min). No ammonia was removed. Side-effects were minimal, although platelets fell 24 +/- 15%. We conclude that haemoperfusion with the filmadsorber is well tolerated and associated with high clearances for bile acids and some amino acids, particularly in the first hours of treatment.