Do aluminum (Al)-hyperaccumulator and phosphorus (P)-solubilising species assist neighbouring plants sensitive to Al toxicity and P deficiency?

We aimed to evaluate the facilitation effects of an aluminum (Al) hyperaccumulator species bearing cluster roots, Gevuina avellana, on the seedling growth and performance of an Al-intolerant and phosphorus (P)-deficient-sensitive plant, Vaccinium corymbosum. For this, seedlings of G. avellana and V. corymbosum were grown alone or together as follows: i) two G. avellana seedlings, ii) one G. avellana + one V. corymbosum and iii) two V. corymbosum, in soil supplemented with Al (as Al2(SO4)3) and in the control (without Al supplementation). We determined relative growth rate (RGR), photosynthetic rate, chlorophyll concentration, lipid peroxidation and Al and nutrient concentration [Nitrogen (N), P, potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), and sulfur (S)] in leaves and roots of both species. The results showed that, in general, G. avellana did not assist V. corymbosum to enhance its RGR nor reduce its Al uptake. However, G. avellana assisted V. corymbosum in enhanced N acquisition and, consequently, to increase its chlorophyll concentration and photosynthetic rate. Besides, V. corymbosum had lower lipid peroxidation in leaves when grown in the soil with high Al supplementation in association with G. avellana. Our results suggest a facilitating effect of G. avellana to V. corymbosum when grown in soils with high Al concentration, by enhancing chlorophyll concentrations and photosynthetic rate, and decreasing the oxidative damage to lipids.

Lesser incidence of accidental catheter removal with femoral versus radial arterial access.

BACKGROUND: Arterial catheterization is a frequent procedure in Intensive Care Units (ICUs). Accidental catheter removal (ACR) can cause severe and potentially life-threatening complications such as severe bleeding and vascular damage. Few data are available on accidental arterial catheter removal, and no studies have been found comparing the incidence of ACR between different arterial catheter sites. OBJECTIVE: To compare the incidence of ACR in femoral and radial arterial catheters. RESEARCH DESIGN: Retrospective study. SETTING: A polyvalent ICU. SUBJECTS: All consecutive patients subjected to femoral or radial arterial catheterization. MEASURES: The incidence of ACR per 100 catheter-days between groups was compared using Poisson regression. We considered ACR as the presence of unintended removal produced by the patient or healthcare personnel. RESULTS: A total of 2419 radial and 1085 femoral arterial catheters were inserted and remained in situ during 14,742 and 6497 days, respectively. We detected 45 cases of ACR with the femoral access and 162 cases with the radial access. The ACR rate was lower with the femoral access (4.1% vs 6.7% in the case of the radial access; p=0.003). Poisson regression analysis confirmed a lower incidence of ACR with the femoral versus the radial access (0.69 vs 1.10 ACR events per 100 catheter-days; OR 0.6, p=0.006, CI95% 0.01-0.83). CONCLUSIONS: The incidence of ACR was found to be lower with the femoral than with the radial arterial catheters. In order to improve patient safety, it could be interesting to exhaustively monitor the incidence of ACR and adopt preventive measures, since ACR can give rise to serious complications.

Acute adrenal insufficiency after cardiac surgery.

Adrenal insufficiency after cardiac surgery can easily be confused during the course of an immediate unstable postoperative period. If unrecognized, this condition may cause serious morbidity and can be fatal. We report on a 43-yr-old female patient with chronic known adrenal insufficiency, who, despite her adequate preoperative replacement therapy, presented with one episode of acute hypoadrenal crisis after elective open heart surgery, which could serve as a model to illustrate the salient clinical features and possible problems in this setting for diagnosing this problem to patients in whom chronic adrenal insufficiency remains unknown.

Mortality prediction in cardiac surgery patients: comparative performance of Parsonnet and general severity systems.

BACKGROUND: Our purpose was to assess the performance of general severity systems (Acute Physiology and Chronic Health Evaluation [APACHE], Simplified Acute Physiology Score [SAPS], and Mortality Probability Models [MPM]) and to compare them with the Parsonnet score to predict mortality after cardiac surgery. METHODS AND RESULTS: This was a prospective observational study of 465 cardiac surgery patients in a tertiary referral center. Probabilities of hospital death for patients were estimated by applying the 4 models and were compared with actual mortality rates. Performance of the 4 systems was assessed by evaluating calibration with the Hosmer-Lemeshow goodness-of-fit test and discrimination with receiver operating characteristic (ROC) curves. chi2 values were 3. 71 for Parsonnet, 4.52 for MPM II0, 4.30 for MPM II24, 5.16 for SAPS II, and 10.57 for APACHE II. The area under the ROC curve was 0.857 for Parsonnet, 0.783 for MPM II0, 0.796 for MPM II24, 0.771 for SAPS II, and 0.803 for APACHE II. CONCLUSIONS: In our experience, the Parsonnet score performs very well, with calibration and discrimination very high, better than general severity systems, and it is an appropriate tool to assess mortality in cardiac surgery patients. In our experience, the general severity systems perform well to predict mortality after cardiac surgery, with high calibration of MPM II24, MPM II0, and SAPS II; minor calibration for APACHE II; and high discrimination for 3 general systems, but not as well as the Parsonnet score.

Hypothesis: the target cell of GM-CSF is a macrophage precursor capable to produce cells with the property to secrete a G-CSF like activity.

The induction of granulocyte and macrophage colony formation by the granulocyte-macrophage colony stimulating factor (GM-CSF) on bone marrow cells (BMC) was evaluated as a function of time in agar cultures. We found that while macrophage cell clusters were very abundant on the first two days of culture, granulocytic cell clusters did not appear until the third day. We also found that macrophage colonies were present from the fourth day of culture, while granulocyte colonies did not appear until the fifth day. When two day cell clusters were transferred to cultures with GM-CSF we observed that only macrophage-colonies developed. On the other hand, when four day clusters were transferred, both granulocyte and macrophage colony formation was obtained in a similar way as the one obtained when using GM-CSF with fresh BMC. Two day clusters did not respond to granulocyte colony stimulating factor (G-CSF) while fourth day clusters generated granulocytic colonies in a similar way as when G-CSF was used with fresh BMC. In order to test the hypothesis that granulocyte colony formation in these assays could be a result of the secretion of G-CSF by the macrophages previously induced by GM-CSF, lysates from macrophage colonies were used to induce colony formation on BMC. We observed that colonies, mainly granulocytic, were induced in a similar way as when G-CSF was used. Finally, the possibility that GM-CSF is just a macrophage inducer with the property to produce cells that secrete G-CSF is discussed.