Opioid antagonists in the treatment of alcohol dependence.

This article reviews the use of opioid antagonists in the pharmacologic treatment of alcohol dependence. The rationale for using the opioid antagonists naltrexone and nalmefene to prevent relapse in alcohol-dependent subjects is discussed by reviewing past and current clinical trials. The role of psychotherapies, particularly coping skills therapy, in combination with opioid antagonists is highlighted in the presentations of the clinical data. Finally, future research directions for opioid antagonists are discussed.

A phase I/II trial of iodine-131-tositumomab (anti-CD20), etoposide, cyclophosphamide, and autologous stem cell transplantation for relapsed B-cell lymphomas.

Relapsed B-cell lymphomas are incurable with conventional chemotherapy and radiation therapy, although a fraction of patients can be cured with high-dose chemoradiotherapy and autologous stem-cell transplantation (ASCT). We conducted a phase I/II trial to estimate the maximum tolerated dose (MTD) of iodine 131 ((131)I)-tositumomab (anti-CD20 antibody) that could be combined with etoposide and cyclophosphamide followed by ASCT in patients with relapsed B-cell lymphomas. Fifty-two patients received a trace-labeled infusion of 1.7 mg/kg (131)I-tositumomab (185-370 MBq) followed by serial quantitative gamma-camera imaging and estimation of absorbed doses of radiation to tumor sites and normal organs. Ten days later, patients received a therapeutic infusion of 1.7 mg/kg tositumomab labeled with an amount of (131)I calculated to deliver the target dose of radiation (20-27 Gy) to critical normal organs (liver, kidneys, and lungs). Patients were maintained in radiation isolation until their total-body radioactivity was less than 0.07 mSv/h at 1 m. They were then given etoposide and cyclophosphamide followed by ASCT. The MTD of (131)I-tositumomab that could be safely combined with 60 mg/kg etoposide and 100 mg/kg cyclophosphamide delivered 25 Gy to critical normal organs. The estimated overall survival (OS) and progression-free survival (PFS) of all treated patients at 2 years was 83% and 68%, respectively. These findings compare favorably with those in a nonrandomized control group of patients who underwent transplantation, external-beam total-body irradiation, and etoposide and cyclophosphamide therapy during the same period (OS of 53% and PFS of 36% at 2 years), even after adjustment for confounding variables in a multivariable analysis.

MLL is fused to CBP, a histone acetyltransferase, in therapy-related acute myeloid leukemia with a t(11;16)(q23;p13.3).

The recurring translocation t(11;16)(q23;p13.3) has been documented only in cases of acute leukemia or myelodysplasia secondary to therapy with drugs targeting DNA topoisomerase II. We show that the MLL gene is fused to the gene that codes for CBP (CREB-binding protein), the protein that binds specifically to the DNA-binding protein CREB (cAMP response element-binding protein) in this translocation. MLL is fused in-frame to a different exon of CBP in two patients producing chimeric proteins containing the AT-hooks, methyltransferase homology domain, and transcriptional repression domain of MLL fused to the CREB binding domain or to the bromodomain of CBP. Both fusion products retain the histone acetyltransferase domain of CBP and may lead to leukemia by promoting histone acetylation of genomic regions targeted by the MLL AT-hooks, leading to transcriptional deregulation via aberrant chromatin organization. CBP is the first partner gene of MLL containing well defined structural and functional motifs that provide unique insights into the potential mechanisms by which these translocations contribute to leukemogenesis.

All patients with the T(11;16)(q23;p13.3) that involves MLL and CBP have treatment-related hematologic disorders.

The involvement of 11q23-balanced translocations in acute leukemia after treatment with drugs that inhibit the function of DNA topoisomerase II (topo II) is being recognized with increasing frequency. We and others have shown that the gene at 11q23 that is involved in all of these treatment-related leukemias is MLL (also called ALL1, Htrx, and HRX). In general, the translocations in these leukemias are the same as those occurring in de novo leukemia [eg, t(9;11), t(11;19), and t(4;11)], with the treatment-related leukemias accounting for no more than 5% to 10% of any particular translocation type. We have cloned the t(11;16)(q23;p13.3) and have shown that it involves MLL and CBP (CREB binding protein). The CBP gene was recently identified as a partner gene in the t(8;16) that occurs in acute myelomonocytic leukemia (AML-M4) de novo and rarely in treatment-related acute myeloid leukemia. We have studied eight t(11;16) patients, all of whom had prior therapy with drugs targetting topo II with fluorescence in situ hybridization (FISH) using a probe for MLL and a cosmid contig covering the CBP gene. Both probes were split in all eight patients and the two derivative (der) chromosomes were each labeled with both probes. Use of an approximately 100-kb PAC located at the breakpoint of chromosome 16 from one patient revealed some variability in the breakpoint because it was on the der(16) in three patients, on the der(11) in another, and split in four others. We assume that the critical fusion gene is 5'MLL/3'CBP. Our series of patients is unusual because three of them presented with a myelodysplastic syndrome (MDS) most similar to chronic myelomonocytic leukemia (CMMoL) and one other had dyserythropoiesis; MDS is rarely seen in 11q23 translocations either de novo or with t-AML. Using FISH and these same probes to analyze the lineage of bone marrow cells from one patient with CMMoL, we showed that all the mature monocytes contained the fusion genes as did some of the granulocytes and erythroblasts; none of the lymphocytes contained the fusion gene. The function of MLL is not well understood, but many domains could target the MLL protein to particular chromatin complexes. CBP is an adapter protein that is involved in regulating transcription. It is also involved in histone acetylation, which is thought to contribute to an increased level of gene expression. The fusion gene could alter the CBP protein such that it is constitutively active; alternatively, it could modify the chromatin-association functions of MLL.

The translocation t(8;16)(p11;p13) of acute myeloid leukaemia fuses a putative acetyltransferase to the CREB-binding protein.

The recurrent translocation t(8;16)(p11;p13) is a cytogenetic hallmark for the M4/M5 subtype of acute myeloid leukaemia. Here we identify the breakpoint-associated genes. Positional cloning on chromosome 16 implicates the CREB-binding protein (CBP), a transcriptional adaptor/coactivator protein. At the chromosome 8 breakpoint we identify a novel gene, MOZ, which encodes a 2,004-amino-acid protein characterized by two C4HC3 zinc fingers and a single C2HC zinc finger in conjunction with a putative acetyltransferase signature. In-frame MOZ-CBP fusion transcripts combine the MOZ finger motifs and putative acetyltransferase domain with a largely intact CBP. We suggest that MOZ may represent a chromatin-associated acetyltransferase, and raise the possibility that a dominant MOZ-CBP fusion protein could mediate leukaemogenesis via aberrant chromatin acetylation.

The t(7;11)(p15;p15) translocation in acute myeloid leukaemia fuses the genes for nucleoporin NUP98 and class I homeoprotein HOXA9.

The t(7;11)(p15;p15) translocation is a recurrent chromosomal abnormality associated primarily with acute myeloid leukaemia (FAB M2 and M4). We present here the molecular definition of this translocation. On chromosome 7 positional cloning revealed the consistent rearrangement of the HOXA9 gene, which encodes a class I homeodomain protein potentially involved in myeloid differentiation. On chromosome 11 the translocation targets the human homologue of NUP98, a member of the GLFG nucleoporin family. Chimaeric messages spliced over the breakpoint fuse the GLFG repeat domains of NUP98 in-frame to the HOXA9 homeobox. The predicted NUP98-HOXA9 fusion protein may promote leukaemogenesis through inhibition of HOXA9-mediated terminal differentiation and/or aberrant nucleocytoplasmic transport.

Stent marker materials for computerized tomograph-assisted implant planning.

This article analyzes different materials incorporated as markers in stents worn by patients undergoing a multiplanar reformatted computerized tomography (MRCT) study of the dental arch for implant placement planning. Forty-five patients were scanned with marked stents. The type of material used for stent markers was evaluated for visibility; ease of analysis in relation to the alveolar ridge crest and adjacent teeth, other markers, or restorations; and relative to its applicability as a presurgical guide. The advantages or disadvantages of each type of marker were discussed. The clinician should be aware of the variety of marker materials available and of the advantages and disadvantages associated with each to optimize the use of the multiplanar reformatted computerized tomography in implant placement planning.

Cloning of the murine homolog of the leukemia-associated PML gene.

PML, a Ring-finger protein, participates in the disruption of normal myeloid differentiation when fused to the retinoic acid receptor alpha (RAR alpha) by the translocation between chromosomes (Chrs) 15 and 17 in acute promyelocytic leukemia (APL). As an initial step in the characterization of PML in species other than human, a murine cDNA clone of the PML gene was isolated and sequenced, and the intron/exon organization of the murine locus determined. The predicted amino acid sequence of the mouse PML protein shows 80% similarity to that of its human homolog. However, the mouse and human proteins show greater than 90% similarity in the proposed functional domains of the proteins. Despite its role in the etiology of APL, PML expression is not detectably altered during granulocytic differentiation in a murine in vitro system. Chromosomal localization of the Pml locus by somatic cell hybrids and by linkage analysis indicates that the gene maps to a region of mouse Chr 9 with known linkage homology to the region on human Chr 15q to which PML has been localized.

Schizophrenia susceptibility associated with interstitial deletions of chromosome 22q11.

We report the results of two studies examining the genetic overlap between schizophrenia and velocardiofacial syndrome. In study A, we characterize two interstitial deletions identified on chromosome 22q11 in a sample of schizophrenic patients. The size of the deletions was estimated to be between 1.5 and 2 megabases. In study B, we examine whether variations in deletion size are associated with the schizophrenic phenotype in velocardiofacial syndrome patients. Our results show that a region of the genome that has been previously implicated by genetic linkage analysis can harbor genetic lesions that increase the susceptibility to schizophrenia. Our findings should facilitate identification and cloning of the schizophrenia susceptibility gene(s) in this region and identification of more homogeneous subgroups of patients.

Comparison of initial lymphoma staging using computed tomography (CT) and magnetic resonance (MR) imaging.

While MR is known to be superior to other imaging methods for detecting marrow involvement by lymphoma, MR is also capable of detecting abnormal lymph nodes. Our objective was to determine whether MR employing short TI inversion recovery (STIR) was comparable to CT in the initial staging of 23 patients with Hodgkin's disease (12 patients) and non-Hodgkin's lymphoma (11 patients). MR images of chest, abdomen, pelvis, and femoral marrow were obtained using the STIR and T1-weighted spin-echo (T1-SE) techniques, employing a protocol initially designed for marrow assessment. In all cases, CT-detected adenopathy was also found by MR. Four patients had marrow involvement by MR, undetected by CT. We conclude that MR and CT may be equivalent imaging modalities in the detection of nodal involvement, and that MR has an advantage in its ability to diagnose marrow involvement. Given the high frequency of focal marrow abnormalities detected by MR in patients with Hodgkin's disease and high-grade non-Hodgkin's lymphoma, MR may be the preferred staging modality for these patients.

A case of acute monocytic leukemia with t(11;17) involving a rearrangement of MLL-1 and a region proximal to the RARA gene.

A case of acute monocytic leukemia with t(11;17)(123;q11-21) arising in a 4-month-old boy is described. The breakpoint on chromosome 11 could be mapped to an 8-kb BamHI fragment within the MLL-1 gene, as seen in the majority of infant leukemias. In situ hybridization with cosmid probes allowed us to map the breakpoint on 17q proximal to the RARA gene, while Southern and Northern analyses showed that the gene was not disrupted by the translocation.

Molecular analysis of simple variant translocations in acute promyelocytic leukemia.

The primary cytogenetic abnormality in acute promyelocytic leukemia (APL; FAB M3) is a reciprocal translocation, t(15;17)(q22;q12), which serves to fuse the PML gene on chromosome 15 to the retinoic acid receptor alpha (RARA) gene on chromosome 17. A PML-RARA fusion message transcribed from the der(15) is thought to mediate leukemogenesis. Two APL patients with simple variants of this translocation, t(3;15)(q21;q22) and t(X;15)(p11;q22), have previously been reported who lack cytogenetic involvement of chromosome 17, although their breakpoint positions on chromosome 15 still suggest the involvement of the PML gene. Here we report on a combined analysis by molecular genetics and in situ hybridization of these two patients, in which we wanted to determine whether the PML gene has alternative fusion partners or whether cryptic rearrangement of the RARA locus has occurred instead. A cryptic involvement of RARA was demonstrated in both patients by a combination of Southern analysis, reverse transcription coupled to PCR (RT-PCR), and fluorescence in situ hybridization. The results indicate an absolute requirement for the rearrangement of the RARA gene in the pathogenesis of APL and underline the importance of RARA during normal myeloid differentiation.

A somatic cell hybrid map of the long arm of human chromosome 17, containing the familial breast cancer locus (BRCA1).

We describe a detailed somatic cell hybrid map of human chromosome 17q11.2-q23, containing the familial breast and ovarian cancer locus (BRCA1) and highly informative closely linked markers. An X-irradiation panel of 38 hamster/human and mouse/human hybrids with fragments of chromosome 17 was generated and characterized with 22 STS markers from this chromosome. A detailed map of 61 probes onto chromosome 17q, subdividing the chromosome arm into 25 regions, was done by using a panel of hybrids with well-defined breakpoints and nine chromosome-mediated gene transfectants. Our localization of RARA, TOP2, EDH17B1 and 2, and possibly WNT3, between THRA1 and D17S181, two markers known to flank BRCA1, suggests that any of these is a potential candidate for the BRCA1 locus. The marker D17S579 (Mfd188), which is believed to be very close to BRCA1, maps closest to the EDH17B genes.

Diagnosis of acute promyelocytic leukaemia by RT-PCR: detection of PML-RARA and RARA-PML fusion transcripts.

Acute promyelocytic leukaemia (APL; AML M3) is identified by a unique t(15;17) translocation which fuses the PML gene to the retinoic acid receptor alpha gene (RARA). Reverse transcription coupled with the polymerase chain reaction (RT-PCR) has been used to develop a diagnostic test for APL based on the PML-RARA fusion message. Separate PCR assays were designed to amplify either PML-RARA (15q+ derived) or RARA-PML (17q- derived) chimaeric transcripts. PML-RARA transcripts were detected in every case from a series of 18 APL patients with cytogenetically confirmed t(15;17) translocations, whereas RARA-PML messages were detected in only 67% (12/18) of these patients. This suggests that it is the 15q+ derivative which mediates leukaemogenesis. Furthermore the PCR approach (or Southern analysis) may be used to identify in which of the alternative PML introns the breakpoint occurs; 52% of cases (15/29 patients) utilize a 5' PML intron and 48% the 3' intron (14/29 cases). Neither the choice of PML intron nor the expression of the 17q- derivative could be correlated with the microgranular variant of APL (M3V), overall survival rate, age, sex or presence of coagulopathy. Finally, the fusion message is undetectable in five remission samples. This indicates a possible use for RT-PCR in monitoring remission patients for evidence of relapse.

Molecular analysis of the t(15;17) translocation in acute promyelocytic leukaemia.

APL (FAB M3) is a unique type of myeloid leukaemia characterized by specific clinical, morphological, cytogenetic and molecular features. An early and accurate diagnosis is necessary to initiate therapy and treat the life-threatening coagulopathy caused by release of procoagulants from the abundant promyelocytic granules. Cytogenetically the disease is characterized by a reciprocal translocation between the long arms of chromosomes 15 and 17, t(15;17)(q21;q22), which is seen in almost every patient with APL but in no other form of malignancy. The presence of this translocation, often as the only karyotypic change, suggests that potentially leukaemogenic sequences are located at the breakpoints and are activated by rearrangement. The recent cloning of the breakpoints by three groups has demonstrated that the retinoic acid receptor alpha gene (RARA) on chromosome 17 is fused to a previously undescribed transcription factor gene, PML, on chromosome 15. The DNA-binding motifs of both the RARA and PML proteins, together with the ligand-binding domain of RARA, are combined in a single fusion protein which may dysregulate either retinoic acid or PML-sensitive pathways. Identification of these dysregulated target genes has become the next molecular goal for research on APL. Intriguingly, some APLs not only express the PML-RARA fusion protein but also the reciprocal RARA-PML fusion protein, although the contribution of this product is unclear. The PML-RARA chimaeric protein is presumably the target during the striking differentiation therapy achieved with all-trans retinoic acid. This therapy induces the malignant promyelocytes to mature and die, rather than continue proliferating. Moreover, it represents the first direct connection between a genetic defect and clinical treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

A previously uncharacterized gene, PML, is fused to the retinoic acid receptor alpha gene in acute promyelocytic leukaemia.

It has become apparent that a number of genes disrupted by chromosomal rearrangements during leukaemogenesis encode protein factors involved in transcriptional regulation (20-25) and PML may be another such gene. The replacement of the NH2-terminal transactivation domain in RAR alpha by the PML putative DNA binding and transactivation domains in the PML/RARA fusion produces a novel chimeric protein which may act to block normal myeloid differentiation through disregulation of the genes normally regulated by either or both of the normal proteins.

Characterization of a zinc finger gene disrupted by the t(15;17) in acute promyelocytic leukemia.

The translocation t(15;17) associated with acute promyelocytic leukemia results in the fusion of the retinoic acid receptor alpha (RARA) gene to the PML gene. Characterization of PML revealed that it is a putative zinc finger protein and potential transcription factor that is commonly expressed, with at least three major transcription products. PML breakpoints cluster in two regions on either side of an alternatively spliced exon. Although leukemic cells with translocations characteristically express only one fusion product, both PML/RARA (on the 15q+ derivative chromosome) and RARA/PML (on the 17q- derivative) are transcribed.