Variants of B cell lymphoma 6 (BCL6) and marked atopy.
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Asthma↗
Biomedical subjects
B W Baron
Publications and source records attributed to B W Baron.
BCL6 can repress transcription from the human immunodeficiency virus type I promoter/enhancer region.
The gene BCL6 encodes a zinc finger protein with similarities to transcription factors. We previously reported that a number of viral genomes, including human immunodeficiency virus type I (HIV-1), contain sequences which are similar to the BCL6 DNA-binding consensus in their promoter regions. Electrophoretic mobility shift assays showed that the full-length BCL6 protein extracted from transfected COS cells and a bacterially expressed truncated protein containing the BCL6 zinc fingers can bind specifically to DNA from the U3 promoter/enhancer region of HIV-1. Transient transfections were performed to analyze the effects of the BCL6 protein on luciferase expression driven by the HIV-1 long terminal repeat (LTR) sequences. Full-length BCL6 significantly repressed luciferase activity compared with multiple controls. We conclude that the BCL6 protein can bind to the HIV-1 promoter-enhancer region and contains a domain upstream of its zinc fingers that can repress transcription from the HIV-1 LTR.
Animals↗
BCL6 encodes a sequence-specific DNA-binding protein.
Chromosomal rearrangements of BCL6 are commonly associated with diffuse large-cell lymphomas. We set out to determine the DNA-binding site of a glutathione-S-transferase fusion protein containing the BCL6 zinc finger region by employing cyclic amplification and selection of targets (CASTing). From oligonucleotides containing 16 central random bases, sequences binding to the protein on glutathione-coated beads were repeatedly selected and amplified by polymerase chain reaction (PCR). The binding sites were cloned and sequenced. A consensus, TTTNNNGNNATNCTTT, was obtained. Protein binding studies of double-stranded oligomers containing point mutations within the 3' CTTT confirmed the binding specificity of this part of the consensus. In addition, evidence indicated that some of the base pairs held constant in the oligonucleotides used for CASTing also contributed to binding.
Base Sequence↗
Severe hypercalcemia following neonatal liver transplantation.
A 3-week-old infant with liver failure underwent an orthotopic liver transplant. Following a prolonged second surgical procedure in which he received massive amounts of blood products, his serum calcium was 31.3. mg/dl (7.8 mmol/l). This patient represents a case of severe hypercalcemia secondary to intraoperative calcium infusions given in an effort to overcome infusion-related citrate toxicity in a neonate with hepatic dysfunction.
Anticoagulants↗
Syphilis-associated Guillain-Barré syndrome: response to plasmapheresis.
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Adult↗
Hematuria in sickle cell anemia--not always benign: evidence for excess frequency of sickle cell anemia in African Americans with renal cell carcinoma.
Between 1952 and 1992, we identified 117 African Americans with renal cell carcinoma (RCC) at the University of Chicago. Three of these had sickle cell disease (SS) and 11 had presumed sickle trait (AS). Based on genotype frequencies, these represented a 16.7-fold excess of SS patients (p < 0.0001), but the incidence of AS patients was as expected. In addition, the median age for the SS patients at presentation with RCC (36 years) was significantly less (p = 0.04) than for the AS patients (55 years). We have found no prior reports of SS in RCC patients and suggest that chronic renal injury from sickling and possible immunosuppressive effects of multiple red cell transfusions may be risk factors. We also suggest the need to be aware of the possibility of RCC in SS patients who may have hematuria solely related to sickling.
Adult↗
Combined plateletpheresis and cytotoxic chemotherapy for symptomatic thrombocytosis in myeloproliferative disorders.
BACKGROUND: Patients with myeloproliferative disorders (MPD) may have symptomatic thrombocytosis develop that requires prompt and sustained lowering of platelet counts to avert serious thrombotic or hemorrhagic sequelae. METHODS: The authors retrospectively studied the short- and long-term effects of plateletpheresis combined with three different chemotherapy regimens (busulfan, hydroxyurea, or busulfan/hydroxyurea) in 30 patients with MPD with symptomatic thrombocytosis. RESULTS: Twenty-nine patients entered first remission (FR) with initial treatment. The average number of plateletphereses to FR was three (standard deviation [SD], +/- 3). Average total dose of busulfan (216 mg) and time to FR (1.6 months) were less than for previously reported patients treated without plateletphereses. Addition of hydroxyurea to busulfan decreased the number of plateletpheresis needed (P = 0.02) but did not additionally reduce the amount of busulfan needed or the time to FR. The shortest time to FR was in the hydroxyurea group (mean, 0.6 +/- 0.3 months), but unmaintained remission could be achieved only in the busulfan-treated groups. With median follow-up of 68 months, median survival was 53 months for the busulfan group, 55 months for the hydroxyurea group, and was undefined with no deaths for the busulfan/hydroxyurea group. Neither fatal complications of recurrent symptomatic thrombocytosis nor development of acute leukemia has occurred, except for progression to blast crisis in two patients with chronic myelogenous leukemia. CONCLUSION: Combined plateletpheresis and chemotherapy is a rapidly effective initial treatment for patients with MPD with symptomatic thrombocytosis. With maintenance therapy or prompt treatment at relapse of disease, prolonged good quality survival can be expected.
Adult↗
Identification of the gene associated with the recurring chromosomal translocations t(3;14)(q27;q32) and t(3;22)(q27;q11) in B-cell lymphomas.
Chromosomal translocations involving chromosome 3, band q27, are among the most common rearrangements in B-cell non-Hodgkin lymphoma. From a bacteriophage lambda library prepared from a lymphoma characterized by a t(3;14)(q27;q32), genomic clones were isolated using a probe from the immunoglobulin heavy chain locus (IGH) joining region. In addition to clones containing an apparently normal IGH rearrangement, others were found to contain one of the translocation breakpoint junctions. Normal chromosome 3 sequences and the reciprocal breakpoint junction were subsequently isolated. DNA probes on each side of the chromosome 3 breakpoint hybridized at high stringency to the DNA of various mammalian species, demonstrating evolutionary conservation. One such probe from the presumptive der(3) chromosome detected an 11-kilobase transcript when hybridized to RNA of B- and T-cell lines. A probe made from partial cDNA clones isolated from a T-cell line hybridized with genomic DNA from both sides of the chromosome 3 breakpoint, indicating that the t(3;14) is associated with a break within the gene on chromosome 3. In situ chromosomal hybridization revealed that the same gene is involved in the t(3;22)(q27;q11). Preliminary nucleotide sequencing shows no identity of the cDNA to gene sequences in available data banks. We propose the name BCL6 (B-cell lymphoma 6) for this gene, since it is likely to play a role in the pathogenesis of certain B-cell lymphomas.
Animals↗
Effect of coarctation on matrix content of experimental aortic atherosclerosis: relation to location, plaque size and blood pressure.
Cynomolgus monkeys were fed an atherogenic diet for 6 months following surgically produced high-grade (n = 10) or mild (n = 16) mid-thoracic aortic coarctation. A diet-control (DC) group (n = 13) was fed the diet without coarctation. High-grade coarctation (HGC) resulted in 74.1% +/- 8.3% stenosis by aortography prior to sacrifice and was associated with systolic brachial blood pressures of 143.3 +/- 26.0 mmHg and gradients across the stenoses of 36.8 +/- 23.6 mmHg. Mild coarctation (MC) resulted in stenoses of 50.9% +/- 12.9%, brachial systolic pressures of 119.4 +/- 25.7 and gradients of 12.5 +/- 15.2 mm Hg (P < 0.01, P = 0.03 and P < 0.005, respectively, compared with HGC). When total plaque cross-sectional area exceeded 0.8 mm2, the entire arterial circumference was usually involved. HGC resulted in complete sparing or minimal plaque formation in sections distal to the stenoses compared with proximal sections (P < 0.001). There were no significant differences between MC and DC animals in plaque location or size. Matrix content increased with plaque area regardless of degree of stenosis or sampling level (P < 0.01), but lesions with more than 75% matrix content were more numerous in distal than in proximal sections despite their smaller size. The number of plaques with greater than 75% matrix content was increased proximal to HGC (P < 0.04). Thus, distal location and plaque size were independent determinants of plaque matrix content and matrix content was increased proximal to HGC regardless of plaque size. Attempts to evaluate effects of various regimens and interventions on plaque composition need to take location and plaque size, as well as blood pressure differences, into account.
Animals↗
HindIII polymorphism in the BCL6 gene.
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Alleles↗
Unique anomalies in cephalothoracopagus janiceps conjoined twins with implications for multiple mechanisms in the abnormal embryogenesis.
The anatomic features of female conjoined twins with the Janiceps type of cephalothoracopagus are described. Abnormalities included bilateral clefts of the alveolar arches, shared rudimentary mandible, high, arched clavicles, multiple rib deformities, single shared foregut and small intestine, absent large intestines, omphalocele, multicystic kidneys, hypoplastic lungs, interconnected aortas and neck vessels, single ovary with elongated uterus in each twin, displaced labia, abnormal segmentation of the vertebrae, spinal dysraphism, diastasis of the symphysis pubis, malrotated lower extremity, bilateral posterior dislocation of the hips, and club feet. There were two hearts with internal anomalies. Both spinal cords had a myelocele in the lumbar region. The abnormalities noted in previous reports of conjoined twins of this type are reviewed and compared. We propose that factors associated with conjoining, dysgenetic (developmental) defects, and deformations resulting from crowding in utero all may have been important in the abnormal development in this case.
Digestive System Abnormalities↗
Extragonadal sex cord tumor with annular tubules in an umbilical hernia sac: a unique presentation with implications for histogenesis.
A sex cord tumor with annular tubules (SCTAT) was found incidentally in an umbilical hernia sac excised from a 66-year-old female. No ovarian lesions were visualized on a computerized tomographic (CT) scan of the pelvis. An exploratory laparotomy with total abdominal hysterectomy, bilateral salpingo-oophorectomy, pelvic lymph node biopsies, and omentectomy likewise showed no gross evidence of tumor. Histologic examination revealed foci of SCTAT scattered in the omentum. The peritoneal washings were positive. The ovaries and pelvic lymph nodes were free of tumor. A second-look laparotomy following six courses of chemotherapy with cyclophosphamide, actinomycin D, and vincristine revealed microscopic tumor deposits in the base of the omental remnant, small bowel mesentery, anterior abdominal peritoneum, and meso-appendix. Clinically, the patient remains well following treatment with whole-abdominal radiation. To our knowledge, this is the first report of SCTAT in the umbilical region and the only case of SCTAT without an identifiable ovarian primary. The literature is reviewed, and the possible histogenesis of the tumor in this location is discussed.
Aged↗
Gastric adenocarcinoma after gastric lymphoma.
Three men and one woman developed intestinal-type moderately or poorly differentiated gastric adenocarcinoma 4 to 15 years after the diagnosis of gastric lymphoma. Treatment of the lymphomas had included partial gastrectomy and follow-up radiotherapy and/or chemotherapy. Review of the literature reveals an additional 12 patients who developed adenocarcinoma 3.5 to 34 years (median, 14.5 years) after diagnosis of gastric lymphoma. In the total series of 16 patients, only four were women, who tended to be younger (median age, 36.5 years) than the men (median, 48.5 years) when lymphoma was diagnosed. Patients with gastric lymphoma seem to have an increased incidence of gastric adenocarcinoma. Carcinoma after gastric lymphoma often arises in the distal stomach and appears to occur irrespective of the type of therapy for the lymphoma.
Adenocarcinoma↗
Changes in plasma factor VIII complex and serum lipid profile during atherogenesis in cynomolgus monkeys.
If endothelial injury plays a prominent role in early atherogenesis, the plasma levels of von Willebrand factor (VWF), which is made within and normally released from endothelial cells, might be expected to rise as a marker of the cellular damage. To evaluate this hypothesis, we measured plasma VWF (as VIIIR:Ag), factor VIII:C, and serum lipids serially up to 37 weeks in 29 adult male cynomolgus monkeys on an atherogenic diet. Factor VIII:C peaked at 113% above baseline by week 10 (p less than 0.0001), then fell and remained 53% below baseline (p less than 0.04) during weeks 20 to 37. However, the overall rise in VWF was not significant. In contrast, serum cholesterol continued to rise after week 21. Serum phospholipids (PL), triglycerides (TG), and free fatty acids (FFA) showed a temporal pattern similar to VIII:C. Significant positive correlations with VIII:C were noted for PL (r = 0.59, p = 0.0001) and TG (r = 0.36, p = 0.0096). At autopsy, small to moderately advanced atherosclerotic lesions were distributed throughout the aortas of the majority of the animals. We conclude that changes in plasma VIIIR:Ag do not correlate with atherogenesis in this model. However, the similar course of VIII:C, TG, and PL suggests that these substances may be involved and perhaps interrelated early in atherogenesis.
Animals↗