PubMed Health⌕ Search

Biomedical subjects

A E Coleman

Publications and source records attributed to A E Coleman.

At least 19 recordsLinked to original sources
PubMed2001

Inducible mutagenesis in TEPC 2372, a mouse plasmacytoma cell line that harbors the transgenic shuttle vector lambdaLIZ.

The plasmacytoma cell line, TEPC 2372, was derived from a malignant plasma cell tumor that developed in the peritoneal cavity of a BALB/c mouse that harbored the transgenic shuttle vector for the assessment of mutagenesis in vivo, lambdaLIZ. TEPC 2372 was found to display the typical features of a BALB/c plasmacytoma. It consisted of pleomorphic plasma cells that secreted a monoclonal immunoglobulin (IgG2b/lambda), was initially dependent on the presence of IL-6 to grow in cell culture, contained a hyperdiploid chromosome complement with a tendency to undergo tetraploidization, and harbored a constitutively active c-myc gene by virtue of a T(6;15) chromosomal translocation. TEPC 2372 was further characterized by the ability to respond to in vitro exposure with 4-NQO (4-nitroquinoline-1-oxide), an oxidative model mutagen, with a vigorous dose-dependent increase in mutagenesis that peaked at a 7.85-fold elevation of mutant rates in lambdaLIZ when compared to background mutant rates in untreated controls. Cotreatment with 4-NQO and BSO (buthionine sulfoximine), a glutathione-depleting compound that causes endogenous oxidative stress, resulted in a 9.03-fold increase in the mutant frequency in lambdaLIZ. These results demonstrated that TEPC 2372, the malignant plasma cell counterpart of the lambdaLIZ-based in vivo mutagenesis assay, may be useful as an in vitro reference point for the further elucidation of oxidative mutagenesis in lymphoid tissues.

Animals↗
PubMed2001

Translocation remodeling in the primary BALB/c plasmacytoma TEPC 3610.

Myc-activating chromosomal 12;15 translocations, the hallmark mutations of inflammation-induced BALB/c plasmacytomas, have recently been shown to undergo remodeling by isotype switch-like genetic recombinations that remove approximately 180 kb of immunoglobulin heavy-chain sequence in the vicinity of the rearranged, expressed Myc gene. Here we combine cytogenetic data on the 12;15 translocation (SKY and FISH) with the molecular analysis of key junction sites (long-range PCR followed by DNA sequencing) to demonstrate that translocation remodeling occurred as an infrequent, stepwise, and disomic tumor progression event in the tetraploid, fully transformed, and transplantable plasmacytoma TEPC 3610. This result was used, in conjunction with previously obtained molecular data on five other primary plasmacytomas, to devise a hypothesis that predicts that the selective pressure to undergo translocation remodeling may be predetermined by the location of the break site in Myc. The pressure may be low if the break occurs 5' of the normal promoter region of Myc, but it may be considerably stronger if the break occurs 3' of the Myc promoter. Published 2001 Wiley-Liss, Inc.

Animals↗
PubMed2001

Conformational differences in the 3-D nanostructure of the immunoglobulin heavy-chain locus, a hotspot of chromosomal translocations in B lymphocytes.

Spectral precision distance microscopy was utilized to detect small but nonetheless consistently present conformational differences between the immunoglobulin heavy-chain gene clusters (IgH) that reside on the two chromosome 12 homologues in all diploid cells of the mouse. The euclidian distance (i.e., the mean arithmetic three-dimensional [3-D] distance) between the 5' most IgH gene, C mu, and the 3' most IgH gene, C alpha, was used as the indicator to define the co-presence of a condensed IgH domain and a relaxed IgH domain in the same cell. In normal and malignant B cells in which IgH is actively rearranged and transcribed, the C mu/C alpha distance (genomic distance approximately 180 kb) was found to range from 87.5 to 121 nm on the condensed IgH domain and from 154 to 207 nm on the relaxed IgH domain. In non-B cells (fibroblasts, neutrophils, and macrophages), in which IgH is inactive, the C mu/C alpha distance was found to range from 136 to 154 nm on the condensed IgH domain and from 250 to 292 nm on the related IgH domain. These results suggested that conformational differences that may predispose the relaxed IgH domain for illegitimate genetic recombinations, such as chromosomal translocations, are likely to exist in many cell types, including B cells. However, in B lymphocytes this structural predisposition may conspire with the lineage-specific ability to activate proto-oncogenes (after juxtaposition to IgH) to positively affect the preferential involvement of the relaxed IgH domain in chromosomal translocations. Additional studies are warranted to validate this working hypothesis.

Animals↗
PubMed2000

Chromosomes 1 and 5 harbor plasmacytoma progressor genes in mice.

Mouse spectral karyotyping (SKY) was employed to analyze 29 primary BALB/c plasmacytomas (PCTs) for the presence of chromosomal aberrations that took place subsequent to the Myc-activating T(12F1;15D2) or T(6C1;15D2) translocations, the initiating oncogenic mutations in plasmacytomagenesis. Recurrent amplifications of chromosome (Chr) 1 (48% prevalence) and promiscuous non-reciprocal translocations of Chr 5 (52% prevalence) suggested the existence of important PCT progressor genes on bands 1B/C and 5F. The additional occurrence of sporadic aberrations (93% prevalence) most likely reflected the general instability of the PCT genome. This instability, however, was not consistent, as two PCTs lacked secondary cytogenetic changes detectable by SKY. Our findings led us to conclude that BALB/c PCTs show a remarkably similar degree of cytogenetic heterogeneity to human multiple myeloma, despite being genetically defined (inbred mouse strain) and uniformly initiated (deregulation of Myc). Published 2000 Wiley-Liss, Inc.

Aneuploidy↗
PubMed2000

Genomic organisation and expression of BCL6 in murine B-cell lymphomas.

BCL6 encodes a transcription factor deregulated by chromosomal translocations in human diffuse large cell B lymphomas (DLCL). This study was designed to determine whether Bcl6 might also be involved in lymphomas of mice. BCL6 protein was expressed at high levels in 90% or more of DLCL but not in low grade B lymphomas. Southern hybridisation studies demonstrated altered organisation of Bcl6 in three primary DLCL and the WEHI 231 B-cell lymphoma cell line but not in low grade tumours. Chromosomal painting and fluorescence in situ hybridisation (FISH) analyses of the WEHI 231 metaphase spreads revealed a T(5;16) translocation with Bcl6 on Chromosome 16 at the translocation breakpoint. Deregulated expression of BCL6 is thus likely to contribute to the genesis of DLCL of mice as well as of humans.

Animals↗
PubMed2000

A bromodomain protein, MCAP, associates with mitotic chromosomes and affects G(2)-to-M transition.

We describe a novel nuclear factor called mitotic chromosome-associated protein (MCAP), which belongs to the poorly understood BET subgroup of the bromodomain superfamily. Expression of the 200-kDa MCAP was linked to cell division, as it was induced by growth stimulation and repressed by growth inhibition. The most notable feature of MCAP was its association with chromosomes during mitosis, observed at a time when the majority of nuclear regulatory factors were released into the cytoplasm, coinciding with global cessation of transcription. Indicative of its predominant interaction with euchromatin, MCAP localized on mitotic chromosomes with exquisite specificity: (i) MCAP-chromosome association became evident subsequent to the initiation of histone H3 phosphorylation and early chromosomal condensation; and (ii) MCAP was absent from centromeres, the sites of heterochromatin. Supporting a role for MCAP in G(2)/M transition, microinjection of anti-MCAP antibody into HeLa cell nuclei completely inhibited the entry into mitosis, without abrogating the ongoing DNA replication. These results suggest that MCAP plays a role in a process governing chromosomal dynamics during mitosis.

Amino Acid Sequence↗
PubMed1999

Late-onset congenital adrenal hyperplasia: a treatable cause of anxiety.

BACKGROUND: Some intermediaries of cortisol synthesis, especially the sulfated ester of dehydroepiandrosterone (DHEAS), are picrotoxin-like antagonists of the gamma-aminobutyric acid A (GABA-A) receptor and exert potent anxiogenic effects. We report 5 men and 7 women with refractory anxiety disorders, who had late-onset congenital adrenal hyperplasia (CAH), and in whom interactions between neuroactive steroids and anomalous brain substrates may have participated in the pathophysiology and treatment of anxiety. METHODS: Twelve patients with refractory anxiety disorders as defined by DSM-IV had elevated DHEAS and specific enzyme deficiencies diagnostic of CAH. All were treated with adrenal suppressive therapy using ketoconazole or low (physiologic) dose glucocorticoids. Anxiety was rated by the Tension Scale of the Profile of Mood States (POMS Tension) questionnaire before and during hormonal treatment. RESULTS: Reduction of DHEAS was associated with lower anxiety scores in all twelve cases. POMS Tension scores decreased by 55%. Hormonal treatment, which failed to lower DHEAS, was ineffective. CONCLUSIONS: These findings suggest that late onset CAH can contribute to anxiety disorders and that adrenal suppressive therapy or inhibition of steroidogenesis with ketoconazole may be efficacious as adjuvant therapy.

Adolescent↗
PubMed1999

Recurrent non-reciprocal translocations of chromosome 5 in primary T(12;15)-positive BALB/c plasmacytomas.

The majority of inflammation-induced peritoneal BALB/c plasmacytomas (approximately 90%) harbor a balanced T(12;15) chromosomal translocation that deregulates the expression of the proto-oncogene c-myc. Recent evidence suggests that the T(12;15) is an initiating tumorigenic mutation that occurs in early plasmacytoma precursor cells. However, plasmacytomas take a long time to develop (average tumor latency approximately 220 days), which suggests that additional tumor progression events may be required to complete oncogenesis. We hypothesized that such tumor progression events may take the form of secondary chromosomal aberrations that can be detected by spectral karyotyping (SKY). We screened the entire chromosome complement of 18 primary BALB/c plasmacytomas carrying the T(12;15) and found in nine tumors (50% recurrence) secondary cytogenetic aberrations that involved bands D, E and F chromosome (Chr) 5. The Chr 5D-F rearrangements were manifested predominantly as unbalanced translocations with various partner chromosomes. This finding led us to propose the existence of an important plasmacytoma progression locus in the central region of Chr 5, which presumably becomes involved in peritoneal plasmacytoma development by promiscuous chromosomal translocations.

Animals↗
PubMed1999

Cytogenetic analysis of the bipotential murine pre-B cell lymphoma, P388, and its derivative macrophage-like tumor, P388D1, using SKY and CGH.

Spectral karyotyping (SKY) and comparative genomic hybridization (CGH) were used to elucidate the divergent cytogenetic make-up of the prototypical bilineage lymphoblastic pre-B lymphoma, P388, and its progenitor macrophage-like tumor, P388D1. P388 was found to be diploid and genomically stable. P388D1 was triploid, highly unstable and characterized by numerous marker chromosomes (Chrs) and composite rearrangements. The karyotype of P388D1 was so complex that its clonal relatedness to P388 would have remained questionable without confirmation by molecular analysis of the clonotypic immunoglobulin heavy-chain and light-chain gene recombinations that coexisted in both tumors. The intrinsic instability of the P388D1 genome was indicated by the observation that only four out of 42 aberrations uncovered by SKY (in a total of 27 metaphases) occurred consistently (100% incidence), whereas 27 changes occurred non-randomly (27 to 96% incidence) and 11 alterations randomly (4 to 11% incidence). Persistent cytogenetic instability was also observed in P388 'macrophages' after phorbol ester- and ionomycin-induced conversion in vitro of P388 lymphoma cells. The 'cytogenetic noise' in these cells was manifested by a multiplicity of sporadic chromosomal aberrations; ie 25 distinct changes were identified by SKY in 40 metaphases. The results in P388D1 and P388 'macrophages' were interpreted to indicate that the myeloid differentiation program in the bipotential pre-B cell lymphoma P388 is invariably characterized by karyotypic instability. The study presented here demonstrates the power of the combined SKY and CGH approach to resolve complicated karyotypes of important and widely used mouse tumors.

Animals↗
PubMed1997

Previously hidden chromosome aberrations in T(12;15)-positive BALB/c plasmacytomas uncovered by multicolor spectral karyotyping.

The majority of BALB/c mouse plasmacytomas harbor a balanced T(12;15) chromosomal translocation deregulating the expression of the proto-oncogene c-myc. Recent evidence suggests that the T(12;15) is an initiating tumorigenic mutation that occurs in early plasmacytoma precursor cells. However, the possible contribution of additional chromosomal aberrations to the progression of plasmacytoma development has been largely ignored. Here we use multicolor spectral karyotyping (SKY) to evaluate 10 established BALB/c plasmacytomas in which the T(12;15) had been previously detected by G banding. SKY readily confirmed the presence of this translocation in all of these tumors and in three plasmacytomas newly identified secondary cytogenetic changes of the c-myc-deregulating chromosome (Chr) T(12;15). In addition, numerous previously unknown aberrations were found to be scattered throughout the genome, which was interpreted to reflect the general genomic instability of plasmacytomas. Instability of this sort was not uniform, however, because only half of the tumors were heavily rearranged. Seven apparent hot spots of chromosomal rearrangements (40% incidence) were identified and mapped to Chrs 1B, 1G-H, 2G-H1, 4C7-D2, 12D, 14C-D2, and XE-F1. Two of these regions, Chr 1B and Chr 4C7-D2, are suspected to harbor plasmacytoma susceptibility loci; Pctr1 and Pctr2 on Chr 4C7-D2 and as yet unnamed loci on Chr 1B. These results suggest that secondary chromosomal rearrangements contribute to plasmacytoma progression in BALB/c mice. To evaluate the biological significance of these rearrangements, SKY will be used in follow-up experiments to search for the presence of recurrent and/or consistent secondary cytogenetic aberrations in primary BALB/c plasmacytomas.

Animals↗
PubMed1997

Monoclonal origin of multicentric Kaposi's sarcoma lesions.

BACKGROUND: Kaposi's sarcoma has features of both hyperplastic proliferation and neoplastic growth. Multiple lesions, in which spindle cells are prominent, often arise synchronously over widely dispersed areas. We tested the hypothesis that the spindle cells in these multicentric lesions originate from a single clone of precursor cells. METHODS: To determine whether Kaposi's sarcoma is a monoclonal disorder, we assessed the methylation patterns of the androgen-receptor gene (HUMARA) in multiple lesions from women with the acquired immunodeficiency syndrome. In polyclonal tissues, about half the copies of each HUMARA allele are methylated, whereas in cells derived from a single clone all the copies of only one allele are methylated. To minimize contamination by normal DNA, we used microdissection to isolate areas composed primarily of spindle cells, the putative tumor cells. RESULTS: Eight patients with a total of 32 tumors were studied. Of these tumors, 28 had highly unbalanced methylation patterns (i.e., predominant methylation of one HUMARA allele). In all the tumors that had unbalanced methylation from a given patient, the same allele predominated. CONCLUSIONS: These data indicate that Kaposi's sarcoma is a disseminated monoclonal cancer and that the changes that permit the clonal outgrowth of spindle cells occur before the disease spreads.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Altered pulsatile secretion of luteinizing hormone in women with epilepsy.

Menstrual disorders and infertility are common among women with epilepsy of temporal lobe origin (TLE). Reproductive endocrine disorders may be the cause. Polycystic ovarian syndrome (PCO) and hypothalamic amenorrhea (hypogonadotropic hypogonadism, HH), in particular, are significantly overrepresented and attributable to hypothalamic dysfunction. We therefore compared the hypothalamic function of 14 women with clinically and electrographically documented TLE with that of eight age-matched normal controls by determining the interictal pulse frequency and amplitude of luteinizing hormone (LH) secretion. Serum for LH measurement was drawn every 15 minutes from 8 AM to 4 PM in both groups. LH pulse frequency values were significantly more variable (p < 0.05) and lower (p < 0.05) among women with TLE than among controls. Women with left temporal EEG foci showed a trend toward higher pulse frequencies compared to women with right foci (p = 0.05 to 0.10). Among five women with reproductive endocrine disorders, the three with PCO had left-sided foci and average LH pulse frequency two times higher than that of the two women with HH, who had right-sided foci. Eight reproductively normal, medically treated women with TLE had significantly lower LH pulse frequencies than did the one reproductively normal, untreated woman with TLE (p < 0.05) and the eight normal controls (p < 0.001). These findings suggest that LH pulse frequencies in women with TLE may be influenced by the laterality of the epileptic focus, the reproductive endocrine status, and the use of antiseizure medications.

Adult↗
PubMed1992

Differential laminar distribution of acetylcholinesterase and butyrylcholinesterase containing tangles in the cerebral cortex of Alzheimer's disease.

A sensitive histochemical method for the visualization of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity was used to determine the laminar distribution of cholinesterase-positive cortical tangles in Alzheimer's disease (AD). In many cortical areas AChE- and BChE-positive tangles displayed a completely overlapping distribution. In other areas the most superficial layers contained only AChE-positive tangles whereas the deepest layers contained only BChE-positive tangles. These observations suggest that some cholinesterase-positive tangles have a predominantly (if not exclusively) AChE-like reactivity whereas others have a reactivity that is predominantly BChE-like. The intermingling of AChE- and BChE-positive tangles in most cortical areas and layers suggests that there may also be a third population in which the two enzymes are equally prominent in the same tangle.

Acetylcholinesterase↗
PubMed1990

OKT3 encephalopathy.

OKT3 therapy for induction immunosuppression in a patient who underwent renal transplantation produced obtundation and quadriparesis associated with computed tomographic scan evidence of brain edema. These findings resolved over 3 days with supportive therapy and OKT3 withdrawal.

Antibodies, Monoclonal↗
PubMed1989

Effect of orally administered L-carnitine on blood ammonia and L-carnitine concentrations in portacaval-shunted rats.

L-Carnitine (16 mmoles per kg, injected intraperitoneally) is reported to protect mice against subsequent injection of ammonium acetate given at the unprotected LD100. The present studies in rats show a variable protective effect of L-carnitine (16 mmoles per kg) administered 1 hr prior to an LD100 dose of ammonium acetate. Survival ranged from 100% to 35%. In two experiments, protection was highly significant; in a third experiment, L-carnitine did not protect against death but did significantly prolong time to death. Although the cause of this variability is not known, the data establish the protective effect in rats of L-carnitine given 1 hr before ammonium acetate. D-Carnitine and deoxycarnitine, chemically related analogs unable to substitute for L-carnitine metabolically, are without protective effect. The protective effect of L-carnitine is short-lived and is, for example, completely lost if ammonium acetate is given 24 hr after L-carnitine administration. In contrast, the free carnitine content of brain rises slowly but continuously for at least 24 hr following a single dose of L-carnitine. The observation that protection from ammonia toxicity is not correlated with brain carnitine levels strongly suggests a major peripheral component to the protective effect. Chronically hyperammonemic (portacaval-shunted) rats were found to have significantly depressed total and free carnitine levels in blood compared to normal and sham-operated controls. The hypocarnitinemia, but not the hyperammonemia, was completely reversed in portacaval-shunted rats given drinking water containing 10 mM L-carnitine.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1987

Short-term metabolic fate of [13N]ammonia in rat liver in vivo.

The short-term metabolic fate of [13N]ammonia in the livers of adult male, anesthetized rats was determined. Following a bolus injection of tracer quantities of [13N]ammonia into the portal vein, the single pass extraction was approximately 93%, in good agreement with the portal-hepatic vein difference of approximately 90%. High performance liquid chromatographic analysis of deproteinized liver samples indicated that labeled nitrogen is exchanged rapidly among components of: mitochondrial aspartate aminotransferase and glutamate dehydrogenase reactions and cytoplasmic aspartate aminotransferase and alanine aminotransferase reactions (t1/2 for the exchange of label toward equilibrium is on the order of seconds). Comparison of specific activities of glutamate and ammonia suggests that at 5 s most labeled glutamate was mitochondrial, whereas at 60 s approximately 93% was cytosolic; this change is presumably brought about by the combined action of the mitochondrial and cytosolic aspartate aminotransferases and the aspartate carrier of the malate-aspartate shuttle. Specific activity measurements of glutamate, alanine, and aspartate are in accord with the proposal by Williamson et al. (Williamson, D.H., Lopes-Vieira, O., and Walker, B. (1967) Biochem. J. 104, 497-502) that the components of the aspartate aminotransferase reaction are in thermodynamic equilibrium, whereas the components of the alanine aminotransferase reaction are in equilibrium but compartmented in the rat liver. Despite considerable label in citrulline at early time points, no radioactivity (less than or equal to 0.25% of the total) was detected in carbamyl phosphate, suggesting very efficient conversion to citrulline with little free carbamyl phosphate accumulating in the mitochondria. Our data also show that some portal vein-derived ammonia is metabolized to glutamine in the rat liver, but the amount is small (approximately 7% of that metabolized to urea) in part because liver glutamine synthetase is located in a small population of perivenous cells "downstream" from the urea cycle-containing periportal cells. Finally, no tracer evidence could be found for the participation of the purine nucleotide cycle in ammonia production from aspartate. The present work continues to emphasize the usefulness of [13N]ammonia for short-term metabolic studies under truly tracer conditions, particularly when turnover times are on the order of seconds.

Alanine Transaminase↗
PubMed1987

Inhibition of lactate production in rat brain extracts and synaptosomes by 3-[4-(reduced 3-pyridine aldehyde-adenine dinucleotide)]-pyruvate.

In basic solutions, pyruvate enolizes and reacts (through its 3-carbon) with the 4-carbon of the nicotinamide ring of NAD+, yielding an NAD-pyruvate adduct in which the nicotinamide ring is in the reduced form. This adduct is a strong inhibitor of lactate dehydrogenase, presumably because it binds simultaneously to the NADH and pyruvate sites. The potency of the inhibition, however, is muted by the adduct's tendency to cyclize to a lactam. We prepared solutions of the pyruvate adduct of NAD+ and of NAD+ analogues in which the -C(O)NH2 of NAD+ was replaced with -C(S)NH2, -C(O)CH3, and -C(O)H. Of the four, only the last analogue, 3-[4-(reduced 3-pyridine aldehyde-adenine dinucleotide)]-pyruvate (RAP) cannot cyclize and it was found to be the most potent inhibitor of beef heart and rat brain lactate dehydrogenases. The inhibitor binds very tightly to the NADH site (Ki approximately 1 nM for the A form). Even at high concentrations (20 microM), RAP had little or no effect on rat brain glyceraldehyde-3-phosphate, pyruvate, alpha-ketoglutarate, isocitrate, soluble and mitochondrial malate, and glutamate dehydrogenases. The glycolytic enzymes, hexokinase and phosphofructokinase, were similarly unaffected. RAP strongly inhibited lactate production from glucose in rat brain extracts but was less effective in inhibiting lactate production from glucose in synaptosomes.

Animals↗