Antifungal drug response in anin vitromodel of dermatophyte nail infection

Despite terbinafine being fungicidal against Trichophyton rubrum in standard NCCLS assays and rapidly accumulating in nails in vivo, onychomycosis patients require prolonged terbinafine treatment to be cured. To investigate this, we developed a more clinically relevant onychomycosis in vitro test model. Human nail powder inoculated with T. rubrum and incubated in liquid RPMI 1640 salt medium, which did not support growth alone, developed extensive and invasive mycelial growth. Antifungal drugs were added at different concentrations and cultures incubated for 1 to 4 weeks. Fungal survival was determined by spreading cultures on PDA plates without drug and measuring CFU after 1 to 4 weeks incubation. Drug activity was expressed as the nail minimum fungicidal concentration (Nail-MFC) required for 99.9% elimination of viable fungus. Terbinafine Nail-MFC was 4 microg/ml after 1 week exposure, decreasing to 1 microg/ml after 4 weeks exposure, much higher than MFCs < or = 0.03 microg/ml determined in standard NCCLS MIC assays. In contrast, other clinically used drugs were unable to kill T. rubrum after 4 weeks incubation in this model. Invasive mycelial growth on nail appears to protect T. rubrum from the cidal action of systemic drugs, thus providing a rationale for the long treatment periods in onychomycosis.

French multi-centric study of 2000 amniotic fluid interphase FISH analyses from high-risk pregnancies and review of the literature

This prospective and multi-centric study confirms the accuracy and the limitations of interphase FISH and shows that any cytogenetics laboratory can perform this technique. With regard to the technical approach, we think that slides must be examined by two investigators, because the scoring may be subjective. The main problem with the AneuVysion kit concerns the alpha satellite probes, and especially the chromosome 18 probe, which is sometimes very difficult to interpret because of the high variability of the size of the spots, and this may lead to false negative and uninformative cases. The best solution would be to replace these probes by locus-specific probes. Concerning clinical management, we offer interphase FISH only in very high-risk pregnancies or/and at late gestational age because of the cost of the test. We think that an aberrant FISH result can be used for a clinical decision when it is associated with a corresponding abnormal ultrasound scan. In other cases, most of the time, we prefer to wait for the standard karyotype.

Minor dysplastic changes are frequently observed in the bone marrow aspirate in elderly patients without haematological disease

Bone marrow aspirates were obtained by sternal puncture prior to sternotomy in 54 volunteers (40 males and 14 females) aged 60 years or more. All underwent surgery for cardiological diseases and had normal blood counts, without any haematological abnormalities. Quantitative examination of these bone marrow aspirates yielded reference ranges for each cell type similar to those obtained in younger adults. However, qualitative analysis revealed certain discrepancies: dysplastic changes were observed frequently, mainly in megakaryocytes and erythroblasts, with a normal growth pattern of haematopoietic progenitor cells. A low proportion of macrophages and mast cells were noted in 30% of the bone marrow aspirates. Lymphoid aggregates, seen in 13% of these samples, were generally of moderate size, contained few mast cells and were non-clonal on immunophenotypic analysis.

The hemidesmosomal protein bullous pemphigoid antigen 1 and the integrin beta 4 subunit bind to ERBIN. Molecular cloning of multiple alternative splice variants of ERBIN and analysis of their tissue expression

The bullous pemphigoid antigen 1 (eBPAG1) is a constituent of hemidesmosomes (HDs), cell-substrate adhesion complexes in stratified epithelia. Although its COOH terminus interacts with intermediate filaments, its NH(2) terminus is important for its recruitment into HDs. To identify proteins that interact with the NH(2) terminus of human eBPAG1, we performed a yeast two-hybrid screen, which uncovered a protein belonging to the LAP/LERP (for LRR and PDZ domain) protein family with 16 NH(2)-terminal leucine-rich repeats and a COOH-terminal PDZ domain. The gene for this LAP/LERP protein comprises at least 26 exons located on the long arm of chromosome 5. In most human tissues, several transcripts were detected differing in the coding region situated upstream of or within the PDZ domain. One of the encoded variants was found to correspond to the recently described protein ERBIN. In yeast and in vitro binding experiments, ERBIN was shown to interact not only with eBPAG1 but also with the COOH-terminal region of the cytoplasmic domain of the integrin beta4 subunit, another component of HDs. Antibodies raised against the COOH terminus showed that ERBIN is expressed in keratinocytes. In transfected epithelial cells the protein, however, was not localized in HDs but was either diffusely distributed over the cytoplasm or concentrated at the basolateral plasma membrane. Because ERBIN had been shown previously to interact with the transmembrane tyrosine kinase receptor Erb-B2, which in turn associates with the integrin beta4 subunit, we suggest that ERBIN provides a link between HD assembly and Erb-B2 receptor signaling.

Autoantibodies to the extracellular and intracellular domain of bullous pemphigoid 180, the putative key autoantigen in bullous pemphigoid, belong predominantly to the IgG1 and IgG4 subclasses

BACKGROUND

Autoantibodies to the extracellular domain (ECD) of bullous pemphigoid (BP) antigen 180 (BP180) are thought to play a crucial part in the pathophysiology of BP.

OBJECTIVES

As the various IgG subclasses have different biological properties, we have sought to assess the relative isotype distribution of IgG to BP180 and their reactivity against the ECD and intracellular domain (ICD) of BP180.

METHODS

The reactivity of 27 sera from patients with BP was assayed by immunoblotting against recombinant proteins covering the ECD and ICD of BP180.

RESULTS

Twenty-seven (100%) and 21 (77%) of 27 BP sera, respectively, contained IgG1 and IgG4 autoantibodies binding to the ECD of BP180. Fourteen (82%) and six (35%) of the 17 BP sera that were reactive with the ICD of BP180 had autoantibodies of the IgG1 and IgG4 subclass, respectively. The profile of the isotype restriction appeared to be similar when the response to the ECD vs. that to the ICD was compared. IgG2 and IgG3 reactivity with BP180 was found less frequently. Patients with BP of longer duration showed a tendency to have, in addition to IgG1, an IgG4 response.

CONCLUSIONS

Consistent with prior evidence indicating that subepidermal blister formation in BP is dependent upon complement activation, the frequent finding of complement-fixing IgG1 autoantibodies to both the ECD and ICD of BP180 might have pathogenic relevance in BP. These findings provide new insights relevant for our understanding of the immune response to BP180, the putative key autoantigen in BP.

Plectin, an unusual target antigen in bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is a blistering disease associated with autoantibodies directed against two components of hemidesmosomes, BP180 and BP230.

OBJECTIVES

To assess whether BP patients have autoantibodies targeting plectin, another hemidesmosomal component showing extensive homology to BP230.

METHODS

Examination of sera from 16 patients with BP, using immunoprecipitation studies followed by immunoblotting.

RESULTS

Serum of one of the 16 (6%) patients with BP contain autoantibodies binding to plectin, while no reactivity was found with sera from three control subjects. Sera from all 16 BP patients immunoprecipitated BP230 from extracts of biosynthetically radiolabelled human keratinocytes.

CONCLUSIONS

Our results indicate that sera from BP patients might contain autoantibodies binding to plectin. Although this protein and BP230 are closely sequence-related, the occurrence of autoantibodies binding to plectin is a rare phenomenon in BP.

The 8p12 myeloproliferative disorder. t(8;19)(p12;q13.3): a novel translocation involving the FGFR1 gene

Translocations affecting the chromosomal locus 8p12 are hallmarks of an atypical stem cell myeloproliferative disorder. These events disrupt the fibroblast growth factor receptor 1 (FGFR1) gene and fuse the FGFR1 C-terminus catalytic domain with unrelated proteins. Here, we report on the characterization of the 19q13.3 locus as the fifth FGFR1 chromosomal partner.

Acute myeloid leukemia with hypergranular cytoplasm: a differential diagnosis of acute promyelocytic leukemia

We report here the case of a woman with acute myeloid leukemia with some blast cells exhibiting acute promyelocytic leukemia (APL)-like hypergranular cytoplasm. The cytologic and cytochemical aspects as well as the mature myeloid phenotype and hemostasis disorders were consistent with the diagnosis of APL. However, no t(15;17), or RARalpha gene, MLL gene or PML gene rearrangement was observed, or any other cytogenetic clonal abnormality. Coexpression on blast cells of CD33 and CD56 without CD34, CD16 or HLA-DR, suggested a myeloid/natural killer cell acute leukemia.

IgG autoantibodies from bullous pemphigoid patients recognize multiple antigenic reactive sites located predominantly within the B and C subdomains of the COOH-terminus of BP230

Bullous pemphigoid is a subepidermal bullous disorder characterized by an autoantibody response against the bullous pemphigoid antigen 230 (BP230) and the bullous pemphigoid antigen 180 (BP180), a cytoplasmic component and a transmembrane component, respectively, of hemidesmosomes. Although immunodominant sequences within the extracellular domain of BP180 have been identified, characterization of the antigenic sites on BP230 is still incomplete. To identify autoantibody-reactive sites on BP230 and to examine whether the targeted regions are contained within functionally important domains, recombinant fragments encompassing almost the entire BP230 were used to assess the reactivity of 25 bullous pemphigoid sera by immunoblotting. Our results demonstrate that (i) the region bearing the B and C subdomains of the COOH-terminus of BP230 contains immunodominant sequences recognized by the majority of bullous pemphigoid sera; (ii) additional autoantibody- reactive sites are present over extended regions of the NH2-terminal half of BP230 without evidence for antigenic cross-reactivity between the NH2- and COOH-termini of BP230; and, finally, (iii) autoantibodies reacting with the BP230 tail predominantly belong to the IgG4 and IgG1 subclasses, suggesting that both autoreactive TH2 and autoreactive TH1 cells regulate the autoantibody response to immunodominant sequences of BP230. As the COOH- terminus of BP230 mediates the attachment of keratin intermediate filaments to the hemidesmosomal plaque, whereas its NH2-terminus contains sequences important for its interaction with other constituents of hemidesmosomes, autoantibodies to BP230 might precipitate subepidermal blister formation and perpetuate the disease not only by eliciting an inflammatory reaction but also by interfering with the function of BP230 and thus the stability of hemidesmosomes.

Immunophenotype of a transient myeloproliferative disorder in a newborn with trisomy 21

Cytologic, immunologic, and cytogenetic studies were performed on the blast cells of a newborn with Down syndrome and transient myeloproliferative disease. This hematologic disorder is uncommon, and occurs primarily in infants with Down syndrome. This boy presented with a high white blood cell count and a high percentage of blast cells, without anemia or thrombocytopenia. Chromosome analysis showed a constitutional trisomy 21 without any other clonal abnormality. A three-color flow cytometric analysis was performed and revealed two different CD45 dim, CD34(+), CD117(+), CD56(+) immature subpopulations: the normal immature myeloid precursor and an immature blast cell population that expressed CD41, CD42, CD61, CD36, CD13, CD1a, and CD2. We postulate that this population could be the leukemic precursor involved in the acute megakaryoblastic leukemia frequently observed in children with Down syndrome.

Multiple amino acid substitutions in lanosterol 14alpha-demethylase contribute to azole resistance in Candida albicans

Lanosterol 14alpha-demethylase (14DM) is the target of the azole antifungals, and alteration of the 14DM sequence leading to a decreased affinity of the enzyme for azoles is one of several potential mechanisms for resistance to these drugs in Candida albicans. In order to identify such alterations the authors investigated a collection of 19 C. albicans clinical isolates demonstrating either frank resistance (MICs > or = 32 microg ml(-1)) or dose-dependent resistance (MICs 8-16 microg ml(-1)) to fluconazole. In cell-free extracts from four isolates, including the Darlington strain ATCC 64124, sensitivity of sterol biosynthesis to inhibition by fluconazole was greatly reduced, suggesting that alterations in the activity or affinity of the 14DM could contribute to resistance. Cloning and sequencing of the 14DM gene from these isolates revealed 12 different alterations (two to four per isolate) leading to changes in the deduced amino acid sequence. Five of these mutations have not previously been reported. To demonstrate that these alterations could affect fungal susceptibility to azoles, the 14DM genes from one sensitive and three resistant C. albicans strains were tagged at the carboxyl terminus with a c-myc epitope and expressed in Saccharomyces cerevisiae under control of the endogenous promoter. Transformants receiving 14DM genes from resistant strains had fluconazole MICs up to 32-fold higher than those of transformants receiving 14DM from a sensitive strain, although Western blot analysis indicated that the level of expressed 14DM was similar in all transformants. Amino acid substitutions in the 14DM gene from the Darlington strain also conferred a strong cross-resistance to ketoconazole. In conclusion, multiple genetic alterations in C. albicans 14DM, including several not previously reported, can affect the affinity of the enzyme for azoles and contribute to resistance of clinical isolates.

Two cases of terminal deletion of chromosome 13: clinical features, conventional and molecular cytogenetic analysis

We report the cases of two unrelated patients with psychomotor retardation and craniofacial abnormalities, in whom cytogenetic studies have revealed a terminal deletion of chromosome 13 confirmed by fluorescence in situ hybridization (FISH). This del(13)(q33.2) is the smallest terminal deletion of the 13q reported so far. Interestingly enough, the serum level of coagulation factors VII and X, whose genes are located in 13q34, were reduced in both patients. These cases illustrate the difficulties in identifying precisely chromosome deletions and demonstrate that FISH techniques allow to obtain a more precise correlation between clinical phenotype and cytogenetic abnormalities.

IgG autoantibodies from bullous pemphigoid (BP) patients bind antigenic sites on both the extracellular and the intracellular domains of the BP antigen 180

Bullous pemphigoid (BP) and gestational pemphigoid (PG) are subepidermal blistering disorders associated with autoantibodies directed against two components of hemidesmosomes: the BP antigen 180 (BP180) and the BP antigen 230 (BP230). Autoantibodies against the extracellular domain (ECD) of BP180 are thought to play an initiatory role in subepidermal blister formation. To characterize the targeted antigenic sites on BP180, we have assessed the reactivity of sera from BP and PG patients against eukaryotic recombinant proteins encompassing various portions of the ECD and the intracellular domain (ICD) of BP180. Twenty-two of 22 (100%) BP sera that immunoblotted BP180 in keratinocyte extracts, bound a mutant form consisting of the entire ECD of BP180, whereas only three of these 22 sera (14%) reacted against the ECD of BP180 lacking the NC16A membrane proximal region. Thirteen out of the 22 (59%) BP sera recognized the ICD of BP180. Circulating IgG from a representative BP patient that was affinity purified against the ECD of BP180 did not bind the ICD when reblotted, indicating that there was no antigenic cross-reactivity between the ECD and the ICD of BP180. Reactivity against the ICD of BP180 was further ascertained by immunofluorescence microscopy studies showing that nine of the 22 (41%) BP sera stained COS-7 cells expressing the ICD of BP180. Using deletion mutants of the ICD of BP180, the majority of the sera was found to recognize the central region of the ICD of BP180. Specifically, an immunodominant region was localized to an 87-amino acid segment located towards the NH2-terminus of BP180. In contrast to BP sera, five of six (83%) PG sera contained IgG that recognized exclusively the NC16A region, whereas none bound to the ICD of BP180. Together, the results indicate that in BP, autoantibody reactivity to BP180 is not exclusively restricted to the NC16A region, but that additional antigenic determinants exist on the ICD of BP180. The observed heterogeneous immune response against BP180 might reflect intramolecular epitope spreading. Because the ICD ofBP180 harbors functionally important regions, it is possible that autoantibodies against the ICD of BP180 have pathogenic significance for the progression of the disease.

Modulation of the enzymatic properties of protein phosphatase 2A catalytic subunit by the recombinant 65-kDa regulatory subunit PR65alpha

All protein phosphatase 2A (PP2A) holoenzymes contain a 36-kDa catalytic subunit (PP2Ac) and a regulatory subunit of 65 kDa (PR65). We have studied the interaction between PP2Ac and PR65 in an in vitro system, using PP2Ac isolated from rabbit skeletal muscle and recombinant PR65alpha expressed in bacteria or insect cells. Bacterially expressed PR65alpha exhibited identical biochemical properties to the protein expressed and isolated from the baculoviral expression system. The association of recombinant PR65 with PP2Ac was very tight (K(D)app = 85 pM) and led to a suppression of PP2A activity, which was maximal (70-80%) when phosphoproteins were used as substrates. When less-structured or smaller substrates (such as phosphopeptides) were used, this inhibition was only 30%. PR65 stimulated PP2Ac activity when the assays were performed in the presence of polycations. This indicates that the PR65 not only serves the previously predicted structural role as a molecular scaffold, but also allosterically modulates the enzymatic properties of PP2Ac. Furthermore, we identified a site of interaction between PP2Ac and PR65alpha by disruption of a stretch of basic amino acids by introduction of a glutamate at position 416. This produced an almost 100-fold reduced affinity for PP2Ac and indicated that this basic motif is an important determinant for the interaction of PR65 and PP2Ac.

Translocation 1;19 in two brain tumors

We report two-cases of brain tumors, one childhood medulloblastoma and one adult glioblastoma with an unusual chromosomal abnormality: a t(1;19)(q23;q13). We analyzed these karyotypes using fluorescence in situ hybridization (FISH) and wonder if this chromosomal aberration could represent a particular entity in these brain tumors like t(1;19) in ALL.

Differential inhibition and posttranslational modification of protein phosphatase 1 and 2A in MCF7 cells treated with calyculin-A, okadaic acid, and tautomycin

Calyculin-A (CA), okadaic acid (OA), and tautomycin (TAU) are potent inhibitors of protein phosphatases 1 (PP1) and 2A (PP2A) and are widely used on cells in culture. Despite their well characterized selectivity in vitro, their exact intracellular effects on PP1 and PP2A cannot be directly deduced from their extracellular concentration because their cell permeation properties are not known. Here we demonstrate that, due to the tight binding of the inhibitors to PP1 and/or PP2A, their cell penetration could be monitored by measuring PP1 and PP2A activities in cell-free extracts. Treatment of MCF7 cells with 10 nM CA for 2 h simultaneously inhibited PP1 and PP2A activities by more than 50%. A concentration of 1 microM OA was required to obtain a similar time course of PP2A inhibition in MCF7 cells to that observed with 10 nM CA, whereas PP1 activity was unaffected. PP1 was predominantly inhibited in MCF7 cells treated with TAU but even at 10 microM TAU PP1 inhibition was much slower than that observed with 10 nM CA. Furthermore, binding of inhibitors to PP2Ac and/or PP1c in MCF7 cells led to differential posttranslational modifications of the carboxyl termini of the proteins as demonstrated by Western blotting. OA and CA, in contrast to TAU, induced demethylation of the carboxyl-terminal Leu309 residue of PP2Ac. On the other hand, CA and TAU, in contrast to OA, elicited a marked decrease in immunoreactivity of the carboxyl terminus of the alpha-isoform of PP1c, probably reflecting proteolysis of the protein. These results suggest that in MCF7 cells OA selectively inhibits PP2A and TAU predominantly affects PP1, a conclusion supported by their differential effects on cytokeratins in this cell line.

Differential inhibition of fungal amd mammalian squalene epoxidases by the benzylamine SDZ SBA 586 in comparison with the allylamine terbinafine

The allylamine class of antifungal compounds are specific inhibitors of squalene epoxidase (SE). However, depending on their chemical structure, allylamine derivatives can be highly selective for either fungal or mammalian SEs. All allylamines tested previously, irrespective of their selectivity, inhibit fungal SEs in a noncompetitive manner and mammalian SEs in a competitive manner. Here we have analyzed the inhibitory properties of the benzylamine SDZ SBA 586 toward fungal and mammalian SEs in comparison to the systemic antimycotic terbinafine, SDZ SBA 586 was, like terbinafine a selective inhibitor of fungal SE. Microsomal SE from the pathogenic yeast candida albicans was sixfold more sensitive to SDZ SBA 586 than to terbinafine, C50: 8 nM versus 44 nM, while the enzyme from the dermatophyte fungus Trichophyton rubrum was slightly less sensitive to SDZ SBA 586 than to terbinafine, IC50: 39 and 18 nM, respectively. Similarly to terbinafine, SDZ SBA 586 inhibited the yeast enzyme in non competitive manner, SDZ SBA 586 also inhibited mammalian microsomal SEs, but only at micromolar concentrations. It was more active than terbinafine toward both guinea pig SE, IC50: 2 microM versus 4 microM, and rat SE, IC50: 11 microM versus 87 microM. However, in contrast to terbinafine as well as allylamines selective for mammalian SE, SDZ SBA 586 was a noncompetitive inhibitor of rat microsomal SE. Interestingly, depending on the source of microsomal SE, binding of terbinafine and SDZ SBA 586 exhibited a positive, indifferent, or negative cooperativity, suggesting that SE is an oligomeric enzyme.

Cloning and expression of squalene epoxidase from the pathogenic yeast Candida albicans

The allylamine antimycotic terbinafine prevents the formation of sterols by specifically inhibiting squalene epoxidase (SE). The biological and biochemical action of terbinafine on fungal pathogens has been well investigated, but little is known at the molecular level. Here we report the cloning, sequencing and expression of the target of terbinafine from the major pathogen Candida albicans. A C. albicans genomic DNA library was constructed in gamma ZAP Express and screened with a DNA fragment obtained by polymerase chain reaction with two primers designed from sequences common to Saccharomyces cerevisiae and rodent SEs. Two types of clone, approximately 3.9 kbp and 4.1 kbp, were isolated. Both contained an identical open reading frame of 1488 nucleotides, while a few sequence differences were found in the flanking regions, suggesting an allelic heterogeneity. The deduced protein sequence of C. albicans SE, 496 amino acids (55324 Da), is 54% and 41% identical to those of S. cerevisiae and rat, respectively. A 1.8-kb transcript was observed on Northern blots of C. albicans mRNA. Polyclonal antibodies, raised against an internal peptide of C. albicans SE, recognized a protein associated with the particulate fraction of M(r) 55000 on Western blots of C. albicans extracts. C. albicans SE was overexpressed in S. cerevisiae with the expression vector pYES2. In homogenates from S. cerevisiae overexpressing the C. albicans protein SE activity was 10-fold higher than the endogenous activity from controls.

Pulsed gradient analysis using a dedicated magnetometer

In magnetic resonance imaging and spectroscopy, knowledge of the magnetic field gradient behavior is very important. This work describes a simple way to characterize the temporal and spatial dependence of the main magnetic field when a gradient is switched. Records are performed with a home-built magnetometer. This device is controlled by a personal computer for recording and processing the NMR signals from an array of small probes spatially distributed and switched by the magnetometer. We present results of measurements on a 2-T superconducting magnet. These results show the residual defects of an active shielded gradient coils system.

Characterization of squalene epoxidase activity from the dermatophyte Trichophyton rubrum and its inhibition by terbinafine and other antimycotic agents

Squalene epoxidase (SE) is the primary target of the allylamine antimycotic agents terbinafine and naftifine and also of the thiocarbamates. Although all of these drugs are employed primarily in dermatological therapy, SE from dermatophyte fungi has not been previously investigated. We report here the biochemical characterization of SE activity from Trichophyton rubrum and the effects of terbinafine and other inhibitors. Microsomal SE activity from T. rubrum was not dependent on soluble cytoplasmic factors but had an absolute requirement for NADPH or NADH and was stimulated by flavin adenine dinucleotide. Kinetic analyses revealed that under optimal conditions the Km for squalene was 13 microM and its Vmax was 0.71 nmol/h/mg of protein. Terbinafine was the most potent inhibitor tested, with a 50% inhibitory concentration (IC50) of 15.8 nM. This inhibition was noncompetitive with regard to the substrate squalene. A structure-activity relationship study with some analogs of terbinafine indicated that the tertiary amino structure of terbinafine was crucial for its high potency, as well as the tert-alkyl side chain. Naftifine had a lower potency (IC50, 114.6 nM) than terbinafine. Inhibition was also demonstrated by the thiocarbamates tolciclate (IC50, 28.0 nM) and tolnaftate (IC50, 51.5 nM). Interestingly, the morpholine amorolfine also displayed a weak but significant effect (IC50, 30 microM). T. rubrum SE was only slightly more sensitive (approximately twofold) to terbinafine inhibition than was the Candida albicans enzyme. Therefore, this difference cannot fully explain the much higher susceptibility (> or = 100-fold) of dermatophytes than of yeasts to this drug. The sensitivity to terbinafine of ergosterol biosynthesis in whole cells of T. rubrum (IC50, 1.5 nM) is 10-fold higher than that of SE activity, suggesting that the drug accumulates in the fungus.

Der(16)t(1;16)(q11;q11) in myelodysplastic syndromes: a new non-random abnormality characterized by cytogenic and fluorescence in situ hybridization studies

The der(16)t(1;16)(q11;q11) is a frequent recurrent rearrangement in solid tumours such as breast carcinomas and Ewings sarcomas. Recently, this abnormality was described also in multiple myeloma. We identified a der(16)t(1;16)(q11;q11) in three patients with myelodysplastic syndrome, either during preleukaemic phase (n = 2) or at the time of blastic transformation (n = 1). Breakpoints were ascertained by fluorescence in situ hybridization (FISH) using specific centromeric alpha-satellite probes and whole chromosome painting for chromosome 1 and chromosome 16. These observations, combined with isolated cases of the literature, suggest that der(16)t(1;16)(q11; q11) is a nonrandom abnormality associated with myelodysplastic syndromes.

Differential methylation and altered conformation of cytoplasmic and nuclear forms of protein phosphatase 2A during cell cycle progression

Protein phosphatase 2A (PP2A) appears to be involved in the regulation of many cellular processes. Control mechanisms that lead to the activation (and deactivation) of the various holoenzymes to initiate appropriate dephosphorylation events remain obscure. The core components of all PP2A holoenzymes are the catalytic (PP2Ac) and 63-65-kD regulatory (PR65) subunits. Monospecific and affinity-purified antibodies against both PP2Ac and PR65 show that these proteins are ubiquitously localized in the cytoplasm and the nucleus in nontransformed fibroblasts. As determined by quantitative immunofluorescence the core subunits of PP2A are twofold more concentrated in the nucleus than in the cytoplasm. Detailed analysis of synchronized cells reveals striking changes in the nuclear to cytoplasmic ratio of PP2Ac-specific immunoreactivity albeit the total amounts of neither PP2Ac nor PR65 in each compartment alters significantly during the cell cycle. Our results imply that differential methylation of PP2Ac occurs at the G0/G1 and G1/S boundaries. Specifically a demethylated form of PP2Ac is found in the cytoplasm of G1 cells, and in the nucleus of S and G2 cells. In addition nuclear PP2A holoenzymes appear to undergo conformational changes at the G0/G1 and G1/S boundaries. During mitosis PP2A is lost from the nuclear compartment, and unlike protein phosphatase 1 shows no specific association with the condensed chromatin.

Der(16)t(1;16)(q10;p10) in multiple myeloma: a new non-random abnormality that is frequently associated with Burkitt's-type translocations

Aneuploidy is a frequent feature in multiple myeloma. Cytogenetic analyses have shown that a 14q+ chromosome resulting from either a t(8;14)(q24;q32) or a t(11;14)(q13;q32) was the most consistent abnormality but no specific chromosomal aberration has been identified in this disease. Bone marrow cells from 121 consecutive patients with multiple myeloma were analyzed cytogenetically by standard banding techniques including RHG, GTG and CBG banding. Cells were cultured for 24-96 h in the presence or in the absence of interleukin-6. Clonal abnormalities were detected in 41 of the 121 patients (34%). A der(16)t(1;16)(q10;p10) abnormality was identified in nine of these 41 patients (22%). Der(16) was identified at diagnosis in five patients, during disease progression in two additional patients, and at the time of a relapse in the two last cases. The t(1;15)(q10;p10) translocation was always unbalanced, resulting in a monosomy 16q in all cases. The CBG banding did not demonstrate dicentric chromosomes and the whole chromosome painting confirmed the der(16). A large number of other chromosomal abnormalities were associated with der(16), including chromosomal rearrangements involving the 8q24 band in five cases. Four of these five cases were Burkitt's-type translocations. This observation suggests that der(16)t(1;16)(q10;p10) could be one of the most frequent chromosomal abnormalities that can be identified in multiple myeloma cells.

The catalytic subunit of protein phosphatase 2A is carboxyl-methylated in vivo

We have used polyclonal antibodies against an internal peptide (residues 169 to 182; Ab169/182) and a peptide corresponding to the carboxyl terminus (residues 299 to 309; Ab299/309) to look for in vivo modifications of protein phosphatase 2A catalytic (PP2Ac) subunit. Treatment of extracts from human breast cancer (MCF7) cells with either alkali or ethanol increased immunoreactivity of PP2Ac subunit severalfold on Western blots with Ab299/309, but did not apparently change molecular weight or isoelectric point of the protein. In contrast, immunoreactivity with Ab169/182 was unchanged by these treatments. Subsequently, we demonstrated that the increase in PP2Ac subunit recognition by Ab299/309 coincides with the demethylation of this protein at the carboxyl-terminal leucine (Leu309). Methylation of PP2Ac subunit, in vitro, increases its activity toward both phosphorylase a and a phosphopeptide. The carboxyl-terminal sequence (TPDYFL) of PP2Ac subunit is completely conserved between mammals, yeast, fruit fly, and plants which suggests that regulation of this enzyme activity by carboxyl-terminal methylation has been conserved during evolution.

Okadaic acid-dependent induction of the urokinase-type plasminogen activator gene associated with stabilization and autoregulation of c-Jun

We have previously shown that the tumor promoter okadaic acid (OA), an inhibitor of protein phosphatases 1 and 2A, transcriptionally induces the urokinase-type plasminogen activator (uPA) gene in LLC-PK1 cells. This induction occurs independently of the protein kinase C- and cAMP-dependent signaling pathways. Here we show that a sequence located 2.0 kilobases upstream of the uPA gene, which resembles an AP-1-recognition sequence, mediates the action of OA. DNA-protein interaction studies, together with mRNA and protein analyses, indicate that c-Jun, but not c-Fos, is involved in OA-dependent uPA gene induction. The appearance of high levels of uPA mRNA and DNA binding activity of c-Jun to the AP-1-like site correspond to the appearance of c-Jun accumulation, suggesting that c-Jun accumulation is a critical event in OA-dependent uPA gene induction. c-Jun protein levels increase significantly between 100 and 160 min following OA treatment, whereas c-Jun translation increases only slightly in this time frame, suggesting that post-translation mechanisms are also involved in c-Jun accumulation. Pulse-chase analyses shows that OA specifically stabilizes c-Jun. We discuss our results with respect to the possibility that protein phosphatase 2A maintains c-Jun in its down-regulated state in LLC-PK1 cells.

New case of t(3;17)(q26;q22) as an additional change in a Philadelphia-positive chronic myelogenous leukemia in acceleration

A new case of t(3;17)(q26;q22) was observed in a Philadelphia-positive (Ph+) chronic myelogenous leukemia in acceleration 1 month before occurrence of the blastic phase. Abnormal megakaryocytopoiesis and thrombopenia were noted, but blast cells did not express platelet markers. The same translocation was previously reported in three myeloproliferative disorders in acceleration or in the process of becoming acute. Translocations or inversions of chromosome 3 with breakpoint involving the band 3q26 were specifically associated with megakaryoblastic acute phase or abnormal megakaryocytopoiesis. This report confirms that the t(3;17)(q26;q22) is a specific nonrandom chromosomal abnormality associated with the acute nonlymphoblastic phase of myeloproliferative disorders and megakaryocytopoiesis dysfunction.

Purification and properties of a casein kinase II-like enzyme from Neurospora crassa

A serine/threonine protein kinase was partially purified from Neurospora crassa. Its physical and catalytic properties were typical of casein kinase II. In vitro, the kinase phosphorylated a calpain like protease from Allomyces arbuscula with higher affinity than a mixture of caseins.

Environmental optimization and shielding for NMR experiments and imaging in the earth's magnetic field

For many years, a number of laboratories have been working on the applications of very low field NMR. In 1985, our laboratory presented the first NMR images using the earth's magnetic field. However, the use of this technique was limited by the weakness of the signal and the disturbing effects of the environment on the signal-to-noise ratio and on the homogeneity of the static magnetic field. Therefore experiments has to be performed in places with low environmental disturbances, such as open country or large parks. In 1986, we installed a new station in Lyon, in the town's hostile environment. Good NMR signals can now be obtained (with a signal-to-noise ratio better than 200 and a time constant T2 better than 3s for 200-mnl water samples and at a temperature of about 40 degrees C). We report the terrace roof of our faculty building. Gradient coils were used to correct the local inhomogeneities of the earth's magnetic field. We show FIDs and MR images of water-filled tubes made with or without these improvements.

[Nutritional study of spun soy proteins]

Most of metabolic studies in man concerning the ability of soya proteins to obtain an equilibrated nitrogen balance have been made with extruded products. Because of the extending development of spun proteins, it seems necessary to study the protein quality of this type of product. A preliminary study in rat (C.E.P. method) was conducted to improve the nutritional value by complementation of the fibers by the way of binder. The metabolic utilization of this protein was evaluated in human subjects during two periods of 10 days. Soya protein cover respectively 78 and 48% of the total protein intake. Under these experimental conditions in which soya proteins constitute an important percentage of the total protein intake, the mean nitrogen balance is near to be equilibrated and the nitrogen utilization does not present any significative difference between the periods. Parallely to the suppression of animal proteins, the introduction of insatured lipids in the diet, has allowed, moreover, to decrease the concentration of the lipidic parameters of the subjects. This study demonstrated the dietetic interest and the ability of the studied product to provide the supplying of the nitrogen balance.

Fear-dependent variations in continuous avoidance behavior of pigs. II. Effects of diazepam on acquisition and performance of Pavlovian fear conditioning and plasma corticosteroid levels

Previously acquired continuous avoidance performance of pigs in a shuttle-box was modified by a Pavlovian fear-conditioning procedure. Diazepam (1 mg/kg) given before the Pavlovian conditioning session prevented the increase in corticosteroids and the impairment of performance in the subsequent test session before the presentation of the fear signal. Diazepam given before the Pavlovian conditioning session and/or the test session did not prevent the increase of response to the CS presentation; however, the temporal pattern of increase differed according to the drug condition: the diazepam treatment on the day of the test significantly delayed the peak of responding to the CS; in pigs treated with diazepam on the day of Pavlovian conditioning and with saline on the day of test, the increase of response was diffuse instead of being localized to the CS presentation period. Pigs treated with diazepam both during learning and performance of fear conditioning showed some evidence of performance facilitation. Usual unitary interpretations cannot account for such results which would appear to be the net result of several intermingled effects among which state-dependent learning, acquisition deficit, and performance facilitation seem to be of importance.