Structural Alteration of Rice Pectin Affects Cell Wall Mechanical Strength and Pathogenicity of the Rice Blast Fungus Under Weak Light Conditions.

Pectin, a component of the plant cell wall, is involved in cell adhesion and environmental adaptations. We generated OsPG-FOX rice lines with little pectin due to overexpression of the gene encoding a pectin-degrading enzyme [polygalacturonase (PG)]. Overexpression of OsPG2 in rice under weak light conditions increased the activity of PG, which increased the degradation of pectin in the cell wall, thereby reducing adhesion. Under weak light conditions, the overexpression of OsPG decreased the pectin content and cell adhesion, resulting in abnormally large intercellular gaps and facilitating invasion by the rice blast fungus. OsPG2-FOX plants had weaker mechanical properties and greater sensitivity to biotic stresses than wild-type (WT) plants. However, the expression levels of disease resistance genes in non-infected leaves of OsPG2-FOX were more than twice as high as those of the WT and the intensity of disease symptoms was reduced, compared with the WT. Under normal light conditions, overexpression of OsPG2 decreased the pectin content, but did not affect cell adhesion and sensitivity to biotic stresses. Therefore, PG plays a role in regulating intercellular adhesion and the response to biotic stresses in rice.

[The experience of laparoscopic radical nephrectomy for renal tumors].

We evaluate the safety and feasibility of laparoscopic radical nephrectomy for renal tumors. Between September 1993 and October 2001, 18 patients with renal tumors underwent laparoscopic radical nephrectomy. The mean patient age was 57.1 years ranging from 36 to 78. Clinical stage was T1N0 in all patients. The mean tumor diameter was 4.0 cm ranging from 1.8 to 7.0. Laparoscopic radical nephrectomy was performed by using the transperitoneal anterior approach on 11 patients and retroperitoneal approach on 7 patients. The specimen was removed through an extended stab wound after blunt segmentation of renal parenchyma in a specimen bag (LapSac). The mean operative time was 405 (270-550) and 453 (325-635) min for the transperitoneal approach and retroperitoneal approach respectively, and the mean blood loss was 281 (52-700) and 223 (10-850) ml, respectively. There was an intraoperative complication of minor splenic injury in 2 patients receiving the transperitoneal approach, which was conservatively managed. Histopathology revealed renal cell carcinoma in 17 patients and renal oncocytoma in one patient. There was no recurrence with a mean follow-up of 28.9 months. Compared with 13 patients who underwent open radical nephrectomy during the same period, laparoscopic nephrectomy has a longer operative time (424 versus 214 min, p < 0.001), equal blood loss (259 versus 210 ml, p = 0.59), quicker resumption of ambulation (1.8 versus 2.5 days, p = 0.016) and food intake (1.4 versus 2.2 days, p = 0.003), shorter postoperative hospital stay (10.9 versus 18 days, p = 0.0016), and a tendency of less frequent analgesic requirements (1.9 versus 4.7 times, p = 0.09). Laparoscopic radical nephrectomy is a safe and useful surgery for renal tumors providing minimal invasiveness.

[A clinical analysis of patients with early-stage prostate cancer managed without initial treatment].

To search for a more suitable qualification indicating watchful waiting, we performed a retrospective study against early-stage prostate cancer patients managed without initial treatment. Thirty-three patients who had not been treated for more than 6 months after diagnosed as T1c or T2 prostate cancer were studied. The median values of total observation period, age at diagnosis, and initial PSA were 27.0 months, 69.0 years old, and 7.0 ng/ml, respectively. Among 28 patients who had had measurement of serum PSA at least three times, seven patients showed a significant PSA elevation when transition of PSA level was analyzed using linear regression analysis. The other patients had been stable or PSA level declined. Between these two groups, there was no significant difference regarding age, initial PSA, PSA density, Gleason score, number of cancer-positive core, and cancer-occupying rate in biopsy specimen. The median PSA doubling time in patients showing PSA elevation was 36.3 months. There were no patients showing PSA elevation among those with a cancer-occupying rate of less than 5%. Clinical disease progression was obviously observed in two cases although one did not show PSA elevation. During the observation period, treatment was eventually started in seven patients. The 5-year rate of no treatment was 53.8%. Although a significant independent factor predicting the future treatment was not identified, univariate analysis revealed that the initial PSA value in patients undergoing treatment was significantly higher than that of those without treatment (p = 0.032). We concluded that early-stage prostate cancer has clinical variability, and regular clinical evaluations as digital rectal examination should be performed when the patient was managed with watchful waiting.