A Gene-for-Gene Relationship Underlying the Species-Specific Parasitism of Avena/Triticum Isolates of Magnaporthe grisea on Wheat Cultivars.

ABSTRACT To elucidate genetic mechanisms of the species-specific parasitism of Magnaporthe grisea, a Triticum isolate (pathogenic on wheat) was crossed with an Avena isolate (pathogenic on oat), and resulting F(1) progeny were subjected to segregation analyses on wheat cvs. Norin 4 and Chinese Spring. We found two fungal loci, Pwt3 and Pwt4, which are involved in the specific parasitism on wheat. Pwt3 operated on both cultivars while Pwt4 operated only on 'Norin 4'. Using the cultivar specificity of Pwt4, its corresponding resistance gene was successfully identified in 'Norin 4' and designated as Rmg1 (Rwt4). The presence of the corresponding resistance gene indicated that Pwt4 is an avirulence locus. Pwt3 was assumed to be an avirulence locus because of its temperature sensitivity. We suggest that gene-for-gene interactions underlie the species-specific parasitism of M. grisea.

Two synchronous solid and cystic tumors of the pancreas.

We report a 17-year-old woman who had two synchronous solid and cystic tumors of the pancreas (SCTP) detected by abdominal echography and computed tomography. There was a 6 x 5 cm mass in the pancreatic body and a 3 x 3 cm mass in the tail, with the two lesions being separate. No distal metastases were detected. The resected tumors consisted of solid and cystic components and both were well demarcated with fibrous capsules. The larger tumor was predominantly solid and the smaller one was mostly hemorrhagic. On microscopy, the tumor cells were small, eosinophilic, and arranged, in part, like pseudorosettes. The tumor cells were immunohistochemically positive for alpha-1 antitrypsin, neuron-specific enolase, and synaptophysin. The final diagnosis was SCTP arising synchronously and independently at two sites. As far as we know, only one case of multicentric SCTP has been reported previously. Local recurrence of SCTP suggests the possibility of multicentric occurrence, and we believe that reports of such cases may increase in the future with advances in echography and computed tomography.

[The indications and results of laparoscopic cholecystectomy].

Laparoscopic cholecystectomy was successfully achieved in 93% of the patients, who required removal of the gallbladder, in our institution. Other reports have also shown that more than 90% of patients who required cholecystectomy, were candidates for laparoscopic cholecystectomy. Serious complications occurred in 2.1% of our series and in 2-4% of the literature. The complications included bile duct injury (around 0.5%) and visceral injury (0.2-0.4%). The incidence of complications resulting from technical failure seems to be higher in laparoscopic cholecystectomy than in conventional cholecystectomy but is acceptable for initial experience. Laparoscopic cholecystectomy will become the standard therapy of gallstone for its effectiveness and less invasiveness.