佐藤 武幸

Genes expressed with day/night rhythms in the mouse liver were searched for by microarray analysis using an in-house array harboring mouse liver cDNAs. The rhythmic expression with a single peak and trough level was confirmed by RNA blot analysis for 3beta-Hsd and Gabarapl1 genes exhibiting a peak in the light phase and Spot14, Hspa8, Hspa5, and Hsp84-1 genes showing a peak in the dark phase. On the other hand, mRNA levels for all of the three fibrinogen subunits, Aalpha, Bbeta and gamma, exhibited two peaks each in the light and dark phases in a synchronized manner. This two-peaked rhythmic pattern of fibrinogen genes as well as the single peak-trough pattern of other genes was diminished or almost completely lost in the liver of Clock mutant mice, suggesting that the two-peaked expression is also under the control of oscillation-generating genes. In constant darkness, the first peak of the expression rhythm of fibrinogen genes was almost intact, but the second peak disappeared. Therefore, although the first peak in the subjective day is a component of the innate circadian rhythm, the second peak seems to require light stimuli. Fasting in constant darkness caused shifts of time phases of the circadian rhythms. Protein levels of the fibrinogen subunits in whole blood also exhibited circadian rhythms. In the mouse and human loci of the fibrinogen gene cluster, a number of sequence elements resembling circadian transcription factor-binding sites were found. The fibrinogen gene locus provides a unique system for the study of two-peaked day/night rhythms of gene expression in a synchronized form.

The objectives were as follows: Firstly, to estimate the overall probability of event-free survival (EFS) and isolated CNS relapse in the studies for children with acute lymphoblastic leukemia (ALL) during the 1980s and 1990s. Secondly, to report the EFS according to presenting features and lineage. Thirdly, to evaluate the treatment results re-classified by the risks of NCI criteria. Four consecutive protocol studies were performed in the Tokyo Children's Cancer Study Group: L81-10 protocol (1981-1984, 189 patients), L84-11 (1984-1989, 484 patents), L89-12 (1989-1992 418 patients) and L92-13 (1992-1995, 347 patients). Overall EFS at 5 years in each protocol was 56.5 +/- 3.8(1 s.e.)%, 71.0 +/- 2.1%, 67.8 +/- 2.3%, and 63.4 +/- 2.7%, respectively. The cumulative isolated CNS relapse rate at 5 years was 8.1 +/- 2.1%, 3.5 +/- 0.9%, 3.6 +/- 1.0%, 1.0 +/- 0.6. The EFS in SR/HR (standard risk/high risk) according to the NCI criteria in B-precursor ALL at 5 years was 61.9 +/- 4.3%/41.4 +/- 7.4% (lineage was not confirmed.), 72.5 +/- 2.6%/63.4 +/- 5.0%, 77.4 +/- 2.7%/56.3 +/- 4.7%, and 67.8 +/- 3.4%/56.7 +/- 5.4% in each protocol. Also EFSs according to NCI SR/HR at 5 years of T-ALL in protocols L84-11, L89-12 and L92-13 were 55.6 +/- 16.6%/60.9 +/- 10.1%, 72.7 +/- 13.4%/51.6 +/- 9.1%, and 77.1 +/- 14.4%/53.6/10.1%, respectively. The truncation of maintenance therapy to 6 months resulted in a decreased EFS in L92-13, particularly due to an increase of bone marrow relapse after cessation of therapy in SR and HR. The NCI risk criteria work properly even in the patients treated by different intensities, so that it makes the comparison possible among the patients in various groups. The overall EFSs in childhood ALL improved in 1980s, but it seemed stable or decreased in 1990s. The short maintenance therapy resulted in poor outcome in SR on the L92-13 protocol. Many of these late relapsers were effectively rescued and over-all survival remained at a high level. The proportion of patients who received cranial irradiation reduced without any increase of the CNS events.

In recent pediatric collaborative studies of acute myeloid leukemia (AML), patients with Down's syndrome (DS) have better outcome than other patients when they were treated according to their intensive AML protocols. This may be attributed to enhanced sensitivity of DS AML cells to selected chemotherapeutic agents. We evaluated a less intensive chemotherapeutic regimen which was specifically designed for children with AML-DS. Remission induction chemotherapy consisted of daunorubicin (25 mg/m(2)/day for 2 days), cytosine arabinoside (100 mg/m(2)/day for 7 days), and etoposide (150 mg/m(2)/day for 3 days). Patients received one to seven courses of consolidation therapy of the same regimen. Thirty-three patients were enrolled on the study and their clinical, hematologic and immunophenotypic features were analyzed. Of the 33 patients, all were younger than 4 years and diagnosed as having acute megakaryoblastic leukemia or myelodysplastic syndrome. All patients achieved a complete remission and estimated 8 year event-free survival rate was 80 +/- 7%. Three patients relapsed and two died due to cardiac toxicity and one due to septic shock. The results of our study showed that patients with AML-DS constitute a unique biologic subgroup and should be treated according to a less intensive protocol designed for AML-DS.

There exists limited information about the usefulness of hemopoietic stem cell transplantation (HSCT) for the treatment of patients with refractory Langerhans cell histiocytosis (LCH), We report here four Japanese pediatric patients with multisystem LCH disease who underwent HSCT between 1994 and 1997, Two of the four patients are doing well without any relapse, However, neither of them shows improved sequelae 3 to 4 years after allogeneic HSCT, although the graft was rejected in one of the cases, The remaining two patients died of septic shock. A review of the literature of II patients revealed four fatalities after the use of HSCT in the treatment of LCH, Three of these were due to active LCH and three deaths occurred within 2 months after HSCT, To establish the usefulness of HSCT for refractory LCH, further studies are required.

A patient with severe diarrhea was successfully diagnosed as having acute intestinal GVHD on stool smear through detection of detached intestinal epithelial cells with apoptosis, Since a stool smear can be easily obtained non-invasively, it is a possible tool for the diagnosis of acute intestinal GVHD.