Element distribution in mycorrhizal and nonmycorrhizal roots of the halophyte Aster tripolium determined by proton induced X-ray emission.

The salt aster (Aster tripolium L.) colonized by the arbuscular mycorrhizal fungus Glomus intraradices Sy167 and noncolonized control plants were grown in a greenhouse for nine months with regular fertilization by Hoagland nutrient solution supplemented with 2% NaCl. Mycorrhizal roots showed a high degree of mycorrhizal colonization of 60-70% and formed approximately 25% more dry weight and much less aerenchyma than the nonmycorrhizal controls. Cryosectioning essentially preserved the root cell structures and apparently did not cause significant ion movements within the roots during cuttings. The experimental conditions, however, did not allow to discriminate between fungal and plant structures within the roots. Quantification of proton-induced X-ray emission (PIXE) data revealed that in control roots, Na(+) was mainly concentrated in the outer epidermal and exodermal cells, whereas the Cl(-) concentration was about the same in all cells of the roots. Cross sections of roots colonized by the mycorrhizal fungus did not show this Na(+) gradient in the concentration from outside to inside but contained a much higher percentage of NaCl among the elements determined than the controls. PIXE images are also presented for the four other elements K, P, S, and Ca. Both in colonized and control roots, the concentration of potassium was high, probably for maintaining homoeostasis under salt stress. This is seemingly the first attempt to localize both Na(+) and Cl(-) in a plant tissue by a biophysical method and also demonstrates the usefulness of PIXE analysis for such kind of investigation.

[Rectal carcinoma. Optimizing the procedures in an emergency]. / Rektumkarzinom. Optimierung des Vorgehens in der Notfallsituation.

Emergency conditions in rectal cancer can happen pre-, intra-, and postoperatively. Preoperative emergencies are perforation and obstipation. Spontaneous intraperitoneal perforations have a mortality of 17 to 33% and a five year survival of only 7 to 10%. The site of the perforation is not identical with the the site of the tumor. Due to fecal peritonitis a defunctioning stoma and planned repeat laparotomies are indicated. Initial fecal diversion is followed by tumor resection with anastomosis when the peritonitis has subsided. Iatrogenic perforations from endoscopy or barium enema examination are rare (0.09 to 0.004%). Tumor obstruction occurs in 15% of colorectal cancers. Immediate resection with primary anastomosis is deemed to be feasible if preceded by on-table colonic lavage. Immediate resection has a lower mortality (13.6%) than two staged fecal diversion and resection (35.5%). Intraoperative emergency conditions are bleeding and tumor cell spillage. Bleeding from the presacral veins will be controlled with the hemorrhage occluder pin. Inadvertent perforation of the tumor leads to dissemination of tumor cells. In case of spillage local recurrence was seen in 39% of resections within five years. Multivisceral resection and precise preparation with respect to anatomical planes may prevent damage of the rectum. The leading postoperative emergency condition is anastomotic leak. The incidence of clinical leaks is 6%. In diffuse peritonitis the anastomosis should be taken down and planned repeat laparotomy should be performed. This concept reduces the mortality down to 18.7%.