A distinct function of the retinoblastoma protein in the control of lipid composition identified by lipidomic profiling.

Here, by combining lipidomics with transcriptome analysis, we demonstrate that Rb depletion in mouse embryonic fibroblastss induces significant alterations in their lipid composition. We discovered that Rb depletion induced increase in lysophosphatidylserine, diacylglycerol (DAG), fatty acid (FA), acylcarnitine, phosphatidylcholine (PC), arachidonoyl ethanolamine, and decrease in phosphatidylglycerol, monoacylglycerol, without change in total lipid per protein levels. Analysis of the acyl chain composition of DAG, PC and phosphatidylserine revealed increase of saturated and mono-unsaturated acyl chains with specific carbon chain length. Consistently, we observed that Rb depletion increased the levels of fatty acids with the corresponding carbon chain length and number of carbon-carbon double bondssuch as myristic acid (14:0), palmitic acid (16:0), stearic acid (18:0) and all forms of FA 18:1. Microarray analysis revealed that Rb depletion induced significant upregulation of enzymes involved in elongation and desaturation of fatty acids. Among these, we found that elongation of long chain fatty acid family member 6 (Elovl6) and stearoyl-CoA desaturase 1 (Scd1) are the most robustly controlled by Rb possibly through E2F and sterol regulatory element-binding protein transcription factors. Depletion of Elovl6 or Scd1 significantly suppressed colony formation, sphere formation and xenograft tumor growth of Rb-deficient tumor cells. Suppression of self-renewal by the SCD1 inhibitor was rescued upon supplementation of the mono-unsaturated fatty acids generated by this enzyme. This study suggests a novel role for Rb in suppressing the malignant progression of tumors by controlling the lipid composition.

Identification of liver X receptor-retinoid X receptor as an activator of the sterol regulatory element-binding protein 1c gene promoter.

In an attempt to identify transcription factors which activate sterol-regulatory element-binding protein 1c (SREBP-1c) transcription, we screened an expression cDNA library from adipose tissue of SREBP-1 knockout mice using a reporter gene containing the 2.6-kb mouse SREBP-1 gene promoter. We cloned and identified the oxysterol receptors liver X receptor (LXRalpha) and LXRbeta as strong activators of the mouse SREBP-1c promoter. In the transfection studies, expression of either LXRalpha or -beta activated the SREBP-1c promoter-luciferase gene in a dose-dependent manner. Deletion and mutation studies, as well as gel mobility shift assays, located an LXR response element complex consisting of two new LXR-binding motifs which showed high similarity to an LXR response element recently found in the ABC1 gene promoter, a reverse cholesterol transporter. Addition of an LXR ligand, 22(R)-hydroxycholesterol, increased the promoter activity. Coexpression of retinoid X receptor (RXR), a heterodimeric partner, and its ligand 9-cis-retinoic acid also synergistically activated the SREBP-1c promoter. In HepG2 cells, SREBP-1c mRNA and precursor protein levels were induced by treatment with 22(R)-hydroxycholesterol and 9-cis-retinoic acid, confirming that endogenous LXR-RXR activation can induce endogenous SREBP-1c expression. The activation of SREBP-1c by LXR is associated with a slight increase in nuclear SREBP-1c, resulting in activation of the gene for fatty acid synthase, one of its downstream genes, as measured by the luciferase assay. These data demonstrate that LXR-RXR can modify the expression of genes for lipogenic enzymes by regulating SREBP-1c expression, providing a novel link between fatty acid and cholesterol metabolism.

Developmental assessment-based surgical intervention for intractable epilepsies in infants and young children.

PURPOSE: To define the most appropriate time for surgery for medically intractable epilepsies in infants and young children. METHODS: First we examined retrospectively the changes in developmental quotients (DQs) during the clinical course and the clinical factors affecting the DQ in 39 consecutive patients younger than 15 years, who underwent surgical treatment for intractable epilepsy. Second, we examined prospectively five new patients for early detection of developmental arrest or regression by periodic developmental assessments and whether this could lead to early surgical intervention, eventually resulting in minimal developmental defects. RESULTS: Retrospective studies revealed that the DQ progressively decreased with age and that the reduction of DQ was related to continuing frequent seizures in many patients. The prospective studies demonstrated that periodic developmental assessments could detect the reduction of DQ at 5 months or later after onset of frequent seizures in three patients. In two other patients, operations were performed before reduction of DQs, and their postoperative DQ levels were normal. The post-operative recovery of DQ was complete in one patient whose operation was performed 3 months after reduction of DQ, whereas it was incomplete in two others whose operations were carried out at 12 and 14 months after reduction, respectively. Furthermore, three patients with normal developmental outcome had shorter periods between the onset of frequent seizures and the operation (< or = 7 months) than those of two patients with developmental delay (> or = 17 months). CONCLUSIONS: To minimize the developmental defects, periodic developmental assessments should be initiated when frequent seizures have occurred, and surgery should be considered as soon as possible when DQ reduction is recognized.

Walker-Warburg syndrome is genetically distinct from Fukuyama type congenital muscular dystrophy.

A female patient who fulfilled the diagnostic criteria of Walker-Warburg syndrome had muscle biopsy finding of muscular dystrophy. There was normal expression of merosin (laminin alpha2 chain) and dystrophin and only slightly reduced dystrophin-associated glycoprotein expression. On genetic analysis, she had no specific haplotype, the common mutation of 3kb insertion, or point mutations in the Fukuyama-type congenital muscular dystrophy gene, suggesting that the two diseases are not genetically identical.

Autosomal dominant onychodystrophy and congenital sensorineural deafness.

The disease "deafness and onychodystrophy" (DOD) is characterized by congenital hearing impairment and dystrophic or absent nails and teeth. The autosomal dominant form of the disorder has been previously reported only in one family. We describe here another family in which three members in three generations (a girl, her mother, and her maternal grandfather) were affected with DOD. Our finding is consistent with an autosomal dominant mode of inheritance and confirms autosomal dominant DOD (DDOD, MIM *124480) as a recognizable clinical entity.

Mouse/human sequence divergence in a region with a paternal-specific methylation imprint at the human H19 locus.

We have identified a region with characteristics of a paternal-specific methylation imprint at the human H19 locus. This region, extending from -2.0 kb upstream to the start of transcription, is heavily methylated in sperm and on the paternal allele in somatic cells. This methylation was preserved during pre-implantation. Structural analysis revealed the presence of CpG islands and a large direct repeat with a 400 bp sequence reiterated several times, but no significant sequence homology to the corresponding region of the mouse H19 gene. These findings could suggest a role for secondary DNA structure in genomic imprinting across the species, and they also present a puzzling aspect of the evolution of the H19 regulatory region in human and mouse.

Normal age-related conversion of bone marrow in the mandible: MR imaging findings.

OBJECTIVE: The mandible is one of the most common sites for osteomyelitis and other marrow-based diseases. Therefore, knowledge of the normal patterns of marrow distribution could help evaluate marrow-based diseases. The purpose of this study was to assess the age-related normal sequence of conversion from hematopoietic to fatty marrow in the mandible as depicted on MR images. SUBJECTS AND METHODS: We prospectively reviewed T1-weighted MR images of the mandible for the distribution of hematopoietic and fatty marrow. Forty-five subjects 4 months to 25 years old with no known marrow abnormality were examined with the spin-echo technique. Marrow conversion was assessed in the condyle, ramus, angle, and body of the mandible using visual grading based on homogeneity, signal intensity, and a signal-intensity ratio determined by the intensities of the surrounding subcutaneous fat and air. RESULTS: Conversion of hematopoietic to fatty marrow occurred first in the mandibular body, followed by the angle, ramus, and finally the condyle. The marrow in the region distal to the ramus had almost fully converted to fatty marrow by the third decade of life, but the remaining regions contained some hematopoietic marrow. Further substantiating these results, the signal-intensity ratio increased up to about 90% in the angle and 70% in the ramus by the age of 10 years and then leveled off. On the other hand, the signal-intensity ratio in the condyle reached 60% by age 15 and remained unchanged for the following 10 years. CONCLUSION: The normal age-related conversion from hematopoietic to fatty marrow in the mandible follows a well-defined sequence, first seen in the mental region early in childhood, then in the body, the ramus, and finally the condyle.

[Efficacy of FEM (5-fluorouracil, epirubicin, mitomycin C) therapy for resected advanced gastric cancer. Ehime Gastric Cancer Study Meeting].

Between April 1990 and March 1991, postoperative adjuvant chemotherapy for resected gastric cancer employing 5-fluorouracil, epirubicin and mitomycin C (FEM) was performed. Forty-two patients subjected to the therapy were considered to have positive serosal invasion and underwent curative operation. FEM therapy consisted of intraoperative intraperitoneal administration of mitomycin C (0.3-0.4 mg/kg) combined with 8 cycles of intravenous bolus injection of epirubicin (20 mg/body) every 2-3 weeks which was started 2 weeks after the operation. Daily oral administration of 5-fluorouracil (150-200 mg/body) was started 2 weeks after the operation and continued for more than 6 months. Thirty-four of the 42 cases were assessable. Major adverse effects were nausea, vomiting, and general fatigue. There were no cardiovascular symptoms. The cumulative two-year survival rate was 74.2%, and follow-up was still under way at this writing.

[A case of giant advanced breast cancer responding remarkably to CEFT therapy].

A fifty-two-year-old female was admitted with unresectable advanced giant breast cancer, which was attached to the chest wall and had a bone metastasis to the thoracic vertebrae. At first, depression and fixation were performed for the bone metastasis, and 2 courses of CEFT therapy were administered. One course was intra-arterial chemotherapy. After 2 courses of treatment, the tumor size was not changed, but tumor marker, CT and physical findings showed a remarkable improvement, and mastectomy could be performed. It was suggested that this regimen is very effective for advanced giant breast cancer.

[Long-term remission of a case of Burkitt's lymphoma accompanied by cardiac tamponade treated by surgical resection and intensive chemotherapy].

A 26-year-old woman was admitted to our hospital because of abdominal mass. She became ileus and an emergency operation was consequently performed. A histological examination of the abdominal tumor indicated proliferation of undifferentiated lymphoblasts with intermingled histiocytes so called "starry sky appearance". The diagnosis was Burkitt's lymphoma. On the 4th post-operative day, a cardiac tamponade became evident. The pericardial effusion contained many lymphoblasts and the diagnosis was pericarditis due to the invasion of lymphoma cells. The pericarditis was successfully treated by infusion of doxycycline into the pericardial space following drainage. The patient responded to systemic chemotherapy with complete remission. 7 courses of systemic chemotherapy along with intrathecal infusions for CNS prophylaxis were subsequently carried out. A state of complete remission has continued for more than 13 months. Cardiac tamponade accompanied by Burkitt's lymphoma is quite rare and has not ever been reported in Japan in our knowledge. The efficacy of surgical treatment before systemic chemotherapy and the series of intrathecal infusions for CNS prophylaxis was demonstrated in this case.