The ASYMMETRIC LEAVES2 gene of Arabidopsis thaliana regulates formation of a symmetric lamina, establishment of venation and repression of meristem-related homeobox genes in leaves.

The asymmetric leaves2 (as2) mutant of Arabidopsis thaliana generated leaf lobes and leaflet-like structures from the petioles of leaves in a bilaterally asymmetric manner. Both the delayed formation of the primary vein and the asymmetric formation of secondary veins were apparent in leaf primordia of as2 plants. A distinct midvein, which is the thickest vein and is located in the longitudinal center of the leaf lamina of wild-type plants, was often rudimentary even in mature as2 leaves. However, several parallel veins of very similar thickness were evident in such leaves. The complexity of venation patterns in all leaf-like organs of as2 plants was reduced. The malformed veins were visible before the development of asymmetry of the leaf lamina and were maintained in mature as2 leaves. In vitro culture on phytohormone-free medium of leaf sections from as2 mutants and from the asymmetric leaves1 (as1) mutant, which has a phenotype similar to that of as2, revealed an elevated potential in both cases for regeneration of shoots from leaf cells. Analysis by the reverse transcription-polymerase chain reaction showed that transcripts of the KNAT1, KNAT2 and KNAT6 (a recently identified member of the class 1 knox family) genes accumulated in the leaves of both as2 and as1 plants but not of wild type. Transcripts of the STM gene also accumulated in as1 leaves. These findings suggest that, in leaves, the AS2 and AS1 genes repress the expression of these homeobox genes, which are thought to maintain the indeterminate cell state in the shoot apical meristem. Taken together, our results suggest that AS2 and AS1 might be involved in establishment of a prominent midvein and of networks of other veins as well as in the formation of the symmetric leaf lamina, which might be related to repression of class 1 knox homeobox genes in leaves.

[Factors leading to home care of patients in the terminal stage of malignant diseases--a study of 10 cases].

In order to clarify the factors that lead patients in the terminal stage of malignant diseases to home care, we interviewed ten families of such patients. Among factors involving patients, a strong desire to stay at home and to spend time at home with the family were initially required. Adequate understanding of the patients and their diseases was also needed by families. Other factors include guaranteed medical services in emergencies and/or 24 hours/day 7 days/week care. Patients requested referrals to family physicians, visiting nurses or community health services to cover outpatient clinic functions. It is concluded that a strong desire to stay at home, adequate understanding by the family and guaranteed medical services in emergencies were three significant factors leading to home care of patients in the terminal stage of malignant diseases.