Light interception principally drives the understory response to boxelder invasion in riparian forests

Since several decades, American boxelder (Acer negundo) is replacing white willow (Salix alba) riparian forests along southern European rivers. This study aims to evaluate the consequences of boxelder invasion on understory community in riparian areas. We determined the understory species richness, composition and biomass in boxelder and white willow stands located in three riparian forests, representative of three rivers with distinct hydrological regimes. We investigated correlation of these variables to soil moisture and particle size, main soil nutrient stocks, potential nitrification and denitrification, tree canopy cover and photosynthetic active radiation (PAR) at the ground level. A greenhouse experiment was then conducted to identify the causal factors responsible for changes in the understory. The effect of soil type, PAR level and water level on the growth and the biomass production of Urtica dioica were examined. A lower plant species richness and biomass, and a modification of community composition were observed for boxelder understory in all sites, regardless of their environmental characteristics. The strongest modification that follows boxelder invasion was the decline in U. dioica, the dominant species of the white willow forest understory. These differences were mainly correlated with a lower incident PAR under boxelder canopy. The greenhouse experiment identified PAR level as the main factor responsible for the changes in U. dioica stem number and biomass. Our results indicate that adult boxelder acts as an ecosystem engineer that decreases light availability. The opportunistic invasion by boxelder leads to important understory changes, which could alter riparian ecosystem functioning

Magnetic resonance imaging (MRI) contrast agents for tumor diagnosis

10.1260/2040-2295.4.1.23Journal of Healthcare Engineering4123-4

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Discrepancy between antihypertensive effect and angiotensin converting enzyme inhibition by captopril

Captopril, an inhibitor of angiotensin converting enzyme, was administered twice daily to 13 hypertensive patients for a mean period of 9 weeks. Continuous blood pressure control in the ambulatory patients was established with a portable blood pressure recorder. Notwithstanding, in eight patients with normal renal function, plasma converting enzyme was found to resume normal activity before administration of the morning dose of captopril. Only in 5 patients with impaired renal function did some blockade of plasma converting enzyme persist for more than 12 hours. Measured plasma converting enzyme activity seemed to reflect total conversion of angiotensin I, including conversion in the pulmonary vascular bed, since changes in its activity were closely paralled by changes in plasma aldosterone levels. Bradykinin accumulation seems unlikely when converting enzyme and thus, presumably, kininase II has resumed normal activity. Captopril administration does not seem to alter plasma epinephrine or norepinephrine levels. Blood pressure reduction in the face of normal angiotensin converting enzyme activity is probably due to hyporesponsiveness of the arterioles to pressor hormones, which may be due to specific renin-related and/or nonspecific effects of captopril

Do mute swan (Cygnus olor) grazing, swan residence and fishpond nutrient availability interactively control macrophyte communities?

International audienc

Prospective comparison of 3 gamma-probes for sentinel lymph node detection in 200 breast cancer patients1

Previous reports have shown that axillary sentinel lymph node (ASLN) radiodetection allows accurate axillary staging for patients with early breast cancer. Radioguided surgery implies the use of a gamma-probe to count the emitted radioactivity of marked ASLNs. Several gamma-probes are commercially available, each with its own properties. The clinical impact of the type of gamma-probe used for ASLN radiodetection remains to be evaluated. METHODS: Three commercially available gamma-probes were evaluated: a scintillator with a bismuth germanate crystal (probe A), a semiconductor with a cadmium telluride crystal (probe B), and a semiconductor with a cadmium zinc telluride crystal (probe C). Two hundred patients with early breast cancer were prospectively enrolled to undergo ASLN radiodetection and axillary lymphadenectomy. ASLN mapping consisted of injecting (99m)Tc-sulfur-colloid around the tumor. For each patient, sentinel lymph nodes were counted successively with the 3 probes and the sensitivity of each gamma-probe was determined from ASLN residual activity. The results of detection rates and false-negative rates for each probe were compared. RESULTS: Mean residual ASLN activity was 52 kBq (range, 0.07-189 kBq). Sensitivity was compared among the 3 probes and found to be best for probe A. The detection rate of probe A was significantly better than that of probe B (93% vs. 86%, P = 0.05) but not different from that of probe C (93% vs. 90%). No differences in false-negative rates were observed among the 3 probes. CONCLUSION: ASLN detection rate depends on the type of gamma-probe used. Because failure to detect the ASLN leads to complete axillary lymphadenectomy, involving local morbidity and other sequelae, the type of gamma-probe must be considered important for sentinel lymph node radiodetectio