Tamoxifen and cancer of the endometrium.
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Breast Neoplasms↗
Biomedical subjects
A Arnold
Publications and source records attributed to A Arnold.
Physical interaction of the retinoblastoma protein with human D cyclins.
The retinoblastoma protein (pRb) functions as a regulator of cell proliferation and in turn is regulated by cyclin-dependent kinases. Cyclins D1 and D3 can form complexes with pRb that resemble those formed by several viral oncoproteins and are disrupted by the adenovirus E1A oncoprotein and derived peptides. These cyclins contain a sequence motif similar to the pRb-binding conserved region II motif of the viral oncoproteins. Alteration of this motif in cyclin D1 prevents formation of cyclin D1-pRb complexes while enhancing the biological activity of cyclin D1 assayed in vivo. We conclude that cyclins D1 and D3 interact with pRb in a fashion distinct from cyclins A and E, which can induce pRb hyperphosphorylation, and that cyclin D1 activity may be regulated by its association with pRb.
Amino Acid Sequence↗
PRAD1/cyclin D1 proto-oncogene: genomic organization, 5' DNA sequence, and sequence of a tumor-specific rearrangement breakpoint.
PRAD1 (previously D11S287) is a putative proto-oncogene at 11q13, activated by overexpression through gene rearrangement or gene amplification in several types of human tumors including parathyroid adenomas, centrocytic lymphomas and other B-cell tumors with t(11;14), and breast cancers. PRAD1 (also CCND1) encodes cyclin D1, which may regulate the G1-S phase transition in the cell cycle. Here, we report the cloning and characterization of the chromosomal PRAD1/cyclin D1 gene and the sequence of its promoter region. The gene spans about 15 kb and has 5 exons; its promoter region has Sp1 binding sites and no obvious TATA box, characteristics of housekeeping genes and growth-regulating genes. Furthermore, an E2F binding motif present close to the major transcription start site may be involved in cell cycle-dependent expression of this gene. We also report the sequence of DNAs spanning joining regions of a reciprocal parathyroid hormone/PRAD1 gene rearrangement in a parathyroid adenoma. Comparison with normal sequences suggests that the rearrangement was not a simple break-and-ligate event, but rather involved multiple steps, including two microdeletions and a microinversion. Very short sequences conserved near the breakpoints and symmetrical elements in the eventually inverted DNA segment might have played a role in this illegitimate complex recombination, which may have similarities with a constitutional translocation in Duchenne muscular dystrophy.
Adenoma↗
A pulsed-field gel electrophoresis (PFGE) map of twelve loci on chromosome 11q11-q13.
We report a pulsed-field gel electrophoresis map of 12 loci on proximal human chromosome 11q. Linkage studies have shown that this region of chromosome 11 contains the genes for familial atopic disease (APY) and multiple endocrine neoplasia type I (MEN1) (4). A physical map containing polymorphic loci will aid in the isolation of these disease genes. The map reported here has two noncontiguous groups of loci accounting for 8 of the 12 loci evaluated. One group spans a maximum distance of 1600 kb and includes D11S146, BCL1, PRAD1, INT2, and HSTF1. The other group includes FTH1, C1NH, and COX8. TCN1, PGA, and PYGM did not yield any comigrating fragments and could not be physically linked on this PFGE map. These data enhance previously published physical maps of proximal 11q by refining the localization of and distances between markers in the BCL1 region. Additionally, new information about the locations and physical relationships between FTH1, C1NH, and COX8 is presented.
Autoradiography↗
Cyclin D and oncogenesis.
The D-type cyclins are among the candidate 'G1 cyclins' in higher eukaryotes that may regulate G1-S-phase progression. The human cyclin D1 gene, also known as PRAD1 (and previously as D11S287), is a putative proto-oncogene strongly implicated in several types of human tumors, including parathyroid adenomas, B-cell neoplasms (as the 'BCL-1 oncogene'), and breast and squamous cell cancers. The mechanism by which deregulated production of cyclin D1/PRAD1, and perhaps other D-type cyclins, contributes to tumor development is only beginning to be deciphered.
Adenoma↗
Importance of timing for thoracic irradiation in the combined modality treatment of limited-stage small-cell lung cancer. The National Cancer Institute of Canada Clinical Trials Group.
PURPOSE: The importance of the timing of thoracic irradiation (TI) in the combined modality therapy of limited-stage small-cell lung cancer (SCLC) was assessed in a randomized trial. METHODS: All 308 eligible patients received cyclophosphamide, doxorubicin, and vincristine (CAV) alternating with etoposide and cisplatin (EP) every 3 weeks for three cycles of each chemotherapy regimen. Patients randomized to early TI received 40 Gy in 15 fractions over 3 weeks to the primary site concurrent with the first cycle of EP (week 3), and late TI patients received the same radiation concurrent with the last cycle of EP (week 15). After completion of all chemotherapy and TI, patients without progressive disease received prophylactic cranial irradiation (25 Gy in 10 fractions over 2 weeks). RESULTS: Although complete remission rates were not significantly different between the two arms, progression-free survival (P = .036) and overall survival (P = .008) were superior in the early TI arm. Patients in the late TI arm had a higher risk of brain metastases (P = .006). CONCLUSION: The early administration of TI in the combined modality therapy of limited-stage SCLC is superior to late or consolidative TI.
Aged↗
The retinoblastoma gene in human pituitary tumors.
Functional inactivation of the retinoblastoma (RB) tumor suppressor gene is important in the pathogenesis of many human tumors. Recently, the frequent occurrence of pituitary tumors was reported in mice genetically engineered to have one defective RB allele, a genetic background analogous to that of patients with familial retinoblastoma. The molecular pathogenesis of human pituitary tumors is largely unknown, and the potential role of RB gene inactivation in these neoplasms has not been examined. Consequently, we studied 20 human pituitary tumors (12 clinically nonfunctioning tumors, 4 somatotroph adenomas, 2 prolactinomas, and 2 corticotroph adenomas) for tumor-specific allelic loss of the RB gene using a highly informative polymorphic locus within the gene. Control leukocyte DNA samples from 18 of these 20 patients were heterozygous at this locus, permitting genetic evaluation of their paired tumor specimens. In contrast to the pituitary tumors in the mouse model, none of these 18 human tumors exhibited RB allelic loss. These findings indicate that RB gene inactivation probably does not play an important role in the pathogenesis of common types of human pituitary tumors.
Adenoma↗
Genetic basis of endocrine disease 5. Molecular genetics of parathyroid gland neoplasia.
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Endocrine System Diseases↗
The effect of mechanical damping loads on disabling action tremor.
Patients with severe action tremor have uncontrollable, relatively rapid oscillatory motion super-imposed on otherwise useable slower voluntary motor activity. Because a mechanical damper produces an opposing force proportional to velocity, applying damping loads to tremorous limbs should attenuate the (high-velocity) tremor component of movement while permitting the slower purposeful portion to proceed relatively unopposed. In this study, the effect of upper extremity damping in three degrees of freedom was examined in 10 patients with cerebellar action tremor due to multiple sclerosis or traumatic brain injury. Variable amounts of damping were applied by prototype energy-dissipating orthoses which generated resistive viscous loads by means of computer-controlled magnetic particle brakes. All patients experienced statistically and functionally significant tremor reduction with the application of damping.
Adult↗
The Canadian experience with intensive fluorouracil, epirubicin and cyclophosphamide in patients with early stage breast cancer.
A multicentre dose-finding pilot study was conducted to determine an intensive regimen of fluorouracil (F), epirubicin (E) plus cyclophosphamide (C) [FEC] that was tolerable and acceptable to patients with node-positive operable (n = 266) or locally advanced (n = 22) breast cancer. Consecutive patients were treated with fluorouracil and epirubicin administered intravenously on days 1 and 8, in addition to cyclophosphamide orally for 14 days. Chemotherapy cycles were repeated at monthly intervals for 6 months, and dosages were increased according to a predetermined protocol. End-points were hospital admissions due to febrile neutropenia and changes in cardiac function as assessed by radionuclide angiography. The first 46 patients were treated with doses of F = 375 mg/m2, E = 50 mg/m2 and C = 75 mg/m2 (level 1), then 42 patients received F = 500 mg/m2, E = 50 mg/m2 and C = 75 mg/m2 (level 2), 69 patients received F = 500 mg/m2, E = 60 mg/m2 and C = 75 mg/m2 (level 3), and 42 patients received F = 500 mg/m2, E = 70 mg/m2 and C = 75 mg/m2 with concurrent antibiotics (level 4). Rates of febrile neutropenia were 8.7% (level 1), 7.1% (level 2), 18.8% (level 3), and 31% (level 4) [p = 0.002]. Accrual to level 4 was discontinued according to study protocol and a further 89 patients were recruited at level 3 dosages with antibiotic prophylaxis (level 3a), resulting in a 5.6% rate of febrile neutropenia. The difference in febrile neutropenia rates between dosage levels 3 and 3a was statistically significant (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗
Chromosome 11 translocation breakpoints at the PRAD1/cyclin D1 gene locus in centrocytic lymphoma.
Centrocytic lymphoma is a CD5-positive B-cell neoplasm. Rearrangements at the chromosome 11q13 bcl-1 breakpoint loci are present in the majority of these lymphomas, as a result of reciprocal translocation with the 14q32 immunoglobulin heavy chain joining genes. Recently, a gene lying approximately 110 kb telomeric of the bcl-1 major translocation cluster breakpoint locus, designated PRAD1, was proposed as a candidate bcl-1 oncogene. Accumulated evidence now indicates that this gene is the postulated bcl-1 oncogene. It encodes a protein with homology to cyclin family proteins designated cyclin D1 (CCND1). In order to determine whether 11q13 translocation breakpoints were present near the PRAD1 coding region in addition to the previously defined bcl-1 sites, we analyzed 27 centrocytic lymphomas by Southern blot using genomic and cDNA probes flanking the first exon of PRAD1. Five samples showed rearrangement at PRAD1 sites. In four of these, the breakpoints could be mapped from approximately one to 25 kb upstream of the first PRAD1 exon; each showed comigration of rearranged PRAD1 and immunoglobulin heavy-chain joining gene bands consistent with the t(11;14)(q13;q32). The fifth case was rearranged with PRAD1 probes only on BamHI-digested DNA, indicating either a point mutation or a polymorphism at this site. This sample also had rearrangement on multiple enzyme digests with the bcl-1 p94PS probe. None of 80 non-centrocytic B-cell neoplasms showed PRAD1 rearrangement. Thus, rearrangement at both bcl-1 and PRAD1 loci is strongly associated with centrocytic lymphoma, and provides a useful molecular marker for classifying this subtype of lymphoma. Furthermore, translocation-induced aberrant expression of the PRAD1 cyclin may lead to deregulated cell cycle control and play an important role in the pathogenesis of centrocytic lymphoma.
Chromosomes, Human, Pair 11↗
Coding sequence of the overexpressed transcript of the putative oncogene PRAD1/cyclin D1 in two primary human tumors.
PRAD1 (cyclin D1) is a recently identified member of the family of cyclin genes, believed to play roles in regulating transitions through the cell cycle. The PRAD1 gene, located at 11q13, has been implicated in the pathogenesis of a variety of tumors, including parathyroid adenomas, t(11;14) bearing B-lymphoid tumors (particularly centrocytic lymphomas) where it is highly likely to be the BCL1 oncogene, and possibly in breast carcinomas and squamous cell cancers of the head and neck as well. PRAD1's tumorigenic influence appears to be effected through overexpression of its normal-sized transcript, but it has not been established whether the transcript's coding sequence is normal or contains oncogenic mutations. We have sequenced the coding region of the overexpressed PRAD1 transcript from two primary tumors with clonal PRAD1 region rearrangements: a benign parathyroid adenoma and a malignant centrocytic lymphoma. Each sequence is identical to the normal PRAD1 cDNA sequence, and presumably encodes normal PRAD1 protein. Thus, PRAD1 likely functions as a direct-acting oncogene whose rearrangement in tumors leads to overexpression or deregulated expression of its normal protein product.
Adenoma↗
Cloning and characterization of human cyclin D3, a cDNA closely related in sequence to the PRAD1/cyclin D1 proto-oncogene.
Cyclins regulate cell cycle progression by complexing with and activating cdc2 or related kinases. PRAD1/cyclin D1 is a recently discovered putative oncogene in several types of human tumors and may regulate G1-S phase progression. We have cloned a related human cDNA, called cyclin D3, from a placental cDNA library by cross-hybridization with PRAD1. In synchronized HeLa cells, the mRNA levels of PRAD1 and cyclin D3 were regulated reciprocally through the cell cycle: cyclin D3 mRNA levels peaked in S phase, where PRAD1 mRNA was lowest in S. In normal human mammary epithelial (70N) cells synchronized by growth factor deprivation and subsequent growth factor stimulation, PRAD1 expression peaked in G1 and declined before S phase, while cyclin D3 expression rose later in G1 and remained elevated in S. Therefore, the close relationship (53.1% identity) between PRAD1 and cyclin D3 does not necessarily imply redundant functions of these candidate G1 cyclins; they may have distinct roles in progression from G1 through S phase.
Amino Acid Sequence↗
Characterization of chromosome 11 translocation breakpoints at the bcl-1 and PRAD1 loci in centrocytic lymphoma.
The chromosome 11q13 bcl-1 locus is rearranged in the majority of centrocytic lymphomas, a CD5-positive B-cell non-Hodgkins lymphoma, as a result of reciprocal translocation with the 14q32 immunoglobulin heavy chain genes. Although several 11q13 bcl-1 breakpoint sites have been characterized, a postulated bcl-1 oncogene was not identified. Recently, however, a gene encoding cyclin D1, designated PRAD1, was proposed as a candidate bcl-1 oncogene; accumulated evidence now indicates this gene is bcl-1. To further characterize 11q13 breakpoints in B-cell neoplasms, we analyzed 26 centrocytic lymphomas and 68 other B-cell cancers by Southern blot using a panel of breakpoint probes spanning 110 kilobases of the bcl-1 and PRAD1 loci. Nineteen centrocytic cases (73%) showed rearrangement, 15 at bcl-1 breakpoint sites and 5 at PRAD1 sites. One case was rearranged at both bcl-1 and PRAD1 loci. All but the latter case showed comigration of rearranged bcl-1 or PRAD1 bands and immunoglobulin heavy chain joining gene bands, consistent with the t(11;14). bcl-1 rearrangement was present in only one of 68 noncentrocytic B-cell neoplasms; none showed PRAD1 rearrangement. Thus, bcl-1 and PRAD1 rearrangement is strongly associated with centrocytic lymphoma, providing a useful molecular marker for classifying this subtype of lymphoma and suggesting an important role for PRAD1 cyclin D1 in the pathogenesis of this neoplasm.
Chromosomes, Human, Pair 11↗
Regulation of retinoblastoma protein functions by ectopic expression of human cyclins.
The retinoblastoma susceptibility gene (RB) product, the retinoblastoma protein (pRb), functions as a regulator of cell proliferation. Introduction of the RB gene into SAOS-2 osteosarcoma cells, which lack functional pRb, prevents cell cycle progression. Such growth-suppressive functions can be modulated by phosphorylation of pRb, which occurs via cell cycle-regulated kinases. We show that constitutively expressed cyclins A and E can overcome pRb-mediated suppression of proliferation. pRb becomes hyperphosphorylated in cells overexpressing these cyclins, and this phosphorylation is essential for cyclin A- and cyclin E-mediated rescue of pRb-blocked cells. This suggests that G1 and S phase cyclins can act as regulators of pRb function in the cell cycle by promoting pRb phosphorylation.
Cell Nucleus↗
Centrocytic lymphoma: a B-cell non-Hodgkin's lymphoma characterized by chromosome 11 bcl-1 and PRAD 1 rearrangements.
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Chromosomes, Human, Pair 11↗
Treatment of diarrhoea in human immunodeficiency virus-infected patients with immunoglobulins from bovine colostrum.
Diarrhoea and weight loss are found in more than 50% of patients with the acquired immunodeficiency syndrome (AIDS). In some patients the symptoms can be very severe, leading to death even in the absence of opportunistic infections. In 30% of these patients, enteric pathogens cannot be identified, and approximately only half of the identifiable aetiologic agents of diarrhoea in patients infected with the human immunodeficiency virus (HIV) were treatable with antibiotics. Immunoglobulins from bovine colostrum (Lactobin, Biotest, Dreieich, FRG) contain high titers of antibodies against a wide range of bacterial, viral and protozoal pathogens as well as against various bacterial toxins. Lactobin (LIG) is quite resistant to 24-h incubation with gastric juice. In a multi-center pilot study 37 immunodeficiency patients with chronic diarrhoea [29 HIV-infected patients, 2 patients with common variable immunodeficiency (CVID), one unidentified immunodeficiency, five patients with graft versus host disease (GvHD) following bone marrow transplantation] were treated with oral LIG (10 g/day for 10 days). Good therapeutic effects were observed. Out of 31 treatment periods in 29 HIV-infected patients 21 gave good results leading to transient (10 days) or long-lasting (more than 4 weeks) normalisation of the stool frequency. The mean daily stool frequency decreased from 7.4 to 2.2 at the end of the treatment. Eight HIV-infected patients showed no response. The diarrhoea recurred in 12 patients within 4 weeks (32.4%), while 19 patients were free of diarrhoea for at least 4 weeks (51.3%). In 5 patients intestinal cryptosporidiosis disappeared following oral LIG treatment. LIG treatment was also beneficial in 4 out of 5 GvHD patients.(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗