MR elastography-based staging of liver fibrosis in Fontan procedure associated liver disease is confounded by effects of venous congestion.

AIM: To compare targeted and global liver stiffness measured by magnetic resonance elastography (MRE) with liver biopsy in patients who have undergone the Fontan procedure, and to assess the relationship between liver stiffness and fibrosis stage. MATERIALS AND METHODS: Targeted and global liver stiffness was compared with a quantification of liver fibrosis measured by percentage of Sirius Red (%SR) staining of biopsy samples. MRE values were compared with three other biopsy-scoring methods: Ishak, Scheuer/Ludwig-Batts/Metavir, and congestive hepatic fibrosis score (CHFS). Additionally, in patients who had two or more MRE studies, global liver stiffness was compared for longitudinal assessment. RESULTS: Thirty-four patients were included in the study, with a mean age of 16.2 years. There was no statistically significant correlation between MRE-derived liver stiffness and Ishak score, Metavir score, %SR staining, and CHFS score. Twenty patients had multiple MRE studies, with a mean age of 16.5 years, and these showed a statistically significant increase in mean liver stiffness from 3.72 to 4.68 (26% increase) within an average period of 24 months. CONCLUSIONS: The lack of correlation of liver stiffness with fibrosis stage observed in this study indicates that the effects of venous congestion in Fontan patients can confound the use of liver stiffness as a biomarker for fibrosis as assessed by percentage of SR staining, Ishak score, Metavir score, and CHFS score. These results provide motivation for further development of magnetic resonance imaging-based biomarkers to increase the specificity in the assessment of Fontan-associated liver disease. A steady increase in liver stiffness observed in these patients may be useful for longitudinal follow-up of liver health.

The role of device closure of patent foramen ovale in patients with cryptogenic stroke.

One of the most frequent causes of cardiac embolism in cryptogenic stroke is a paradoxical embolus, which originate from systemic venous source though an unidentified patent foramen ovale (PFO). PFO is a common finding in the general population with a prevalence of 25% to 30%. Transcatheter PFO device closure is known to be feasible and safety treatment for such patients. In recent years, several randomized controlled trials (RCTs) have been conducted to address the superiority of PFO closure over medical therapy alone in the prevention of stroke recurrence in patients with PFO. In contrast to findings from early 3 RCTs, recent 4 RCTs could successfully show the benefits of PFO device closure compared with medical therapy, with less peri- and postprocedural complication. Based on these data, PFO device closure is recommended to carefully select cryptogenic stroke patients aged from 18 to 65 years, with a high probability of a causal role of the PFO in stroke events. However, it is still uncertain whether PFO closure is superior to oral anticoagulants therapy in these patients. Therefore, further prospective randomized trials are needed to address the efficacy of PFO device closure to oral anticoagulants therapy.

ALK rearrangements in EBUS-derived transbronchial needle aspiration cytology in lung cancer.

OBJECTIVES: Patients with non-small cell lung cancer (NSCLC) positive for anaplastic lymphoma kinase (ALK) gene rearrangements may be treated successfully with the ALK inhibitor crizotinib. ALK copy-number abnormalities have also been described. In this study, we evaluated the suitability of fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) to determine ALK status in endobronchial ultrasound (EBUS)-derived cytology samples. METHODS: Samples were obtained from 55 consecutive patients with NSCLC who had undergone EBUS-transbronchial needle aspiration (TBNA) according to our standard clinical protocols. All tumours had been screened previously for epithelial growth factor receptor (EGFR) and v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations. FISH, using commercially available ALK rearrangement-specific probes, was employed to assess ALK status. IHC using the ALK-1 monoclonal antibody (DAKO) was also performed. RESULTS: FISH analysis was successful in 52 of 55 samples (94.5%); ALK rearrangement was demonstrated in 3 of 52 samples from patients with NSCLC (5.7%). ALK amplification was observed in 3 of 52 patient samples (5.7%) and an increase in ALK copy number was found in 28 of 52 patient samples (53.8%). IHC on cell blocks demonstrated ALK expression in one of three samples with ALK rearrangement. One patient sample had concomitant ALK rearrangement and KRAS mutation. CONCLUSIONS: We found FISH to be superior to IHC using the ALK-1 monoclonal antibody for the detection of ALK rearrangement in EBUS-TBNA cytology specimens in NSCLC, and also that ALK rearrangement can co-exist with KRAS mutation in the same tumour.

Proliferation-associated SNF2-like gene (PASG): a SNF2 family member altered in leukemia.

To identify genes involved in cell growth and/or apoptosis in leukemia, differential display was used to identify mRNAs that showed altered expression levels after cytokine withdrawal from the cytokine-dependent MO7e cell line. Sequence analysis of one transcript that showed a profound decrease in expression after cytokine withdrawal revealed it to be a member of the SNF2 family of chromatin remodeling ATPases. This cDNA had a 2514-nucleotide (838-amino acid) open reading frame and encoded an additional 230 amino acids at the NH2 terminus compared with the murine homologue, lsh, and the human counterpart, Hells. This gene locus has been designated SMARCA6 (SWI/SNF2-related, matrix-associated, actin-dependent regulator of chromatin, subfamily A, member 6). The highest levels of mRNA expression in humans are observed in proliferative tissues such as the thymus, testis, and bone marrow. Whereas cytokine withdrawal in MO7e cells leads to apoptosis and decreased mRNA expression, growth arrest without the induction of apoptosis of MO7e cells also leads to down-regulation of mRNA expression, suggesting an association with cell proliferation and not suppression of apoptosis. Nuclear localization of this SNF2-like putative helicase is dependent on a nuclear localization sequence located in the NH2-terminal region. Based on sequence homology to other SNF2-like helicases, the pattern of tissue expression, and the association of expression with cell proliferation, we refer to the protein product as proliferation-associated SNF2-like gene product [PASG (D. W. Lee et al., Blood, 94: 594a, 1999)]. Examination of acute myelogenous leukemia and acute lymphoblastic leukemia samples revealed a high frequency of a PASG transcript containing an in-frame 75-nucleotide deletion, which codes for a conserved motif known to be critical for the transactivation activity of a related yeast SWI/SNF polypeptide. These results extend our knowledge of this SNF2-like family member and suggest a role for PASG in leukemogenesis.

Distribution of restriction enzyme recognition sequences on broad host range plasmid RP4: molecular and evolutionary implications.

IncP alpha plasmids, exemplified by RP4, are remarkable for their broad host range. They contain strikingly few cleavage sites for many commonly used type II restriction enzymes but an overabundance of sites for certain enzymes that target G + C-rich sequences. To identify factors responsible for these distributions, the recently compiled nucleotide sequence of RP4 was analysed to determine the frequency of tetra- and hexanucleotide motifs in the 49 kb plasmid backbone. This is defined as the sectors encoding basic plasmid functions. The overabundant restriction targets in RP4 are concentrated in the backbone and contain overlapping copies of CGGC/GCCG, identified as the most abundant tetranucleotide motif in the plasmid. Motif frequencies in the RP4 backbone are shown to be similar to those in Pseudomonas aeruginosa, a natural host of RP4, with the notable exception that a number of 6-bp palindromes are underrepresented in the plasmid. It is proposed that 6-bp palindromes were counterselected as type II restriction enzyme recognition sequences. Conjugative transfer of RP4 and R751 (IncP beta) is unusually sensitive to restriction compared to enterobacterial plasmids of the IncFII and IncI1 groups, implying that IncP plasmids experienced particularly strong selection for loss of restriction targets. Pseudomonas spp. of rRNA homology group I specify many type II restriction enzymes that target 6-bp palindromes and are candidates for the evolutionary hosts of IncP alpha plasmids.

Complete sequence of the IncPbeta plasmid R751: implications for evolution and organisation of the IncP backbone.

The broad host range IncP plasmids are of particular interest because of their ability to promote gene spread between diverse bacterial species. To facilitate study of these plasmids we have compiled the complete sequence of the IncPbeta plasmid R751. Comparison with the sequence of the IncPalpha plasmids confirms the conservation of the IncP backbone of replication, conjugative transfer and stable inheritance functions between the two branches of this family. As in the IncPalpha genome the DNA of this backbone appears to have been enriched for the GCCG/CGGC motifs characteristic of the genome of organisms with a high G+C content, such as P. aeruginosa, suggesting that IncPbeta plasmids have been subjected during their evolution to similar mutational and selective forces as IncPalpha plasmids and may have evolved in pseudomonad hosts. The IncP genome is consistently interrupted by insertion of phenotypic markers and/or transposable elements between oriV and trfA and between the tra and trb operons. The R751 genome reveals a family of repeated sequences in these regions which may form the basis of a hot spot for insertion of foreign DNA. Sequence analysis of the cryptic transposon Tn4321 revealed that it is not a member of the Tn21 family as we had proposed previously from an inspection of its ends. Rather it is a composite transposon defined by inverted repeats of a 1347 bp IS element belonging to a recently discovered family which is distributed throughout the prokaryotes. The central unique region of Tn4321 encodes two predicted proteins, one of which is a regulatory protein while the other is presumably responsible for an as yet unidentified phenotype. The most striking feature of the IncPalpha plasmids, the global regulation of replication and transfer by the KorA and KorB proteins encoded in the central control operon, is conserved between the two plasmids although there appear to be significant differences in the specificity of repressor-operator interactions. The importance of these global regulatory circuits is emphasised by the observation that the operator sequences for KorB are highly conserved even in contexts where the surrounding region, either a protein coding or intergenic sequence, has diverged considerably. There appears to be no equivalent of the parABCDE region which in the IncPalpha plasmids provides multimer resolution, lethality to plasmid-free segregants and active partitioning functions. However, we found that the continuous sector from co-ordinate 0 to 9100 bp, encoding the co-regulated klc and kle operons as well as the central control region, could confer a high degree of segregational stability on a low copy number test vector. Thus R751 appears to exhibit very clearly what was first revealed by study of the IncPalpha plasmids, namely a fully functional co-ordinately regulated set of replication, transfer and stable inheritance functions.

Criteria for the definition of Epstein-Barr virus association in Hodgkin's disease.

There is a clear association between the Epstein-Barr virus (EBV) and Hodgkin's disease (HD). EBV is not, however, detectable within the affected tissues of all cases. The proportion of positive cases varies from 15-79% depending on the assay used to detect EBV. The techniques utilised vary not only in sensitivity but in their ability to detect viral DNA, RNA, or protein and in their ability to demonstrate the cellular localisation of the virus. Thus, the biological significance of a positive result will vary depending on the method of analysis. In the present study, four different methods of detecting EBV were compared. RNA in situ hybridization was found to be the most practical method of detecting EBV in tumour cells. Using this assay EBV was detected in the Reed-Sternberg cells of 33% and 45% of the two series of HD cases examined in this study. We believe that these cases should be considered EBV-associated.

Immunophenotypic characterization of stromal cells in aspirated human bone marrow samples.

The presence of stromal cells was investigated in aspirated bone marrow prepared by the same method as that used for the initiation of human long-term bone marrow culture (hLTBMC). In previous studies, we performed immunocytochemical staining of cytocentrifuge cell preparations using a panel of antibodies with which we characterized stromal cell populations in hLTBMC. This approach allowed morphological as well as immunophenotypic assessment of cells of interest. Morphologically distinctive cell populations expressing vascular cell adhesion molecule-1 and low-affinity nerve growth factor receptor (NGFR) were observed to be present, but no cells expressing alpha-smooth muscle actin were found. Few macrophages were present, consistent with the origin of hLTBMC stroma-adherent macrophages from monocytes and their precursor cells rather than from mature macrophages among the culture-initiating cells. In the absence of double immunostaining, it was not possible to deduce whether CD34+ cells, which were present in varying numbers in the cytocentrifuge preparations, included stromal as well as primitive hematopoietic cells. In addition to single cells, multicellular tissue fragments containing a variety of stromal cell types were detected in many samples. Their presence raises the possibility that at least some components of hLTBMC stroma may arise by explant growth from complex tissue fragments containing vascular and fibroblastic elements. Overall, our results indicate that demonstration of a variety of stroma-associated antigens, in particular NGFR, provides a useful new tool for identifying stromal elements in aspirated bone marrow.

Techniques for obtaining differential cell counts from bone marrow trephine biopsy specimens.

Differential cell counts were performed on 200 paired bone marrow aspirates and trephine biopsy specimens to compare the distribution of cell types. Relatively more immature myeloid cells were found in the trephine biopsy specimens and relatively more polymorphs and lymphocytes in the aspirates. Two methods for sampling areas of the trephine biopsy specimens for counting were assessed, and the differences between aspirates and trephine specimens were found to be more consistent when the second, more extensive, sampling method was used. This method also permitted quantitation of some features of bone marrow topography and provided information that would not normally be obtainable from aspirated material. The techniques were easy to apply and took relatively little time to perform. They could offer useful information in the study of bone marrow disorders, particularly those such as myelodysplastic syndromes in which disturbances of marrow architecture are prominent.

Bacteriological examination of removed cerebrospinal fluid shunts.

A conventional method of bacteriological examination of removed cerebrospinal fluid shunts was compared with another method which relies on microscopic and cultural examination of intraluminal fluid. Fifty-five shunts were tested. All eight cases of clinical shunt infection gave positive results with the latter method, whereas a further 23 shunts yielded positive cultures by the conventional method in the absence of clinical infection. The consequences of missed infections due to omission of microscopic examination and overdiagnosis using the conventional culture method are discussed.

Fatal disseminated fusarium infection in acute lymphoblastic leukaemia in complete remission.

Fusarium species are increasingly recognised as serious pathogens in the immunocompromised. The outcome in the context of persistent severe neutropenia has been almost universally fatal. However, there have been several case reports of successful treatment if neutrophil recovery can be achieved. This report presents the case of a fatality that occurred despite neutrophil recovery. A 67 year old man developed disseminated fusariosis during the neutropenic phase of induction chemotherapy for acute lymphoblastic leukaemia. Fusarium dimerum was isolated from blood cultures. This species is highly unusual and very few case reports exist in the literature. An initial response to amphotericin treatment coincided with neutrophil recovery but a subsequent relapse occurred, despite adequate neutrophil counts, which proved fatal. It is postulated that reseeding of the blood from an occult site, namely the right vitreum in this case, led to this secondary relapse despite achieving complete leukaemic remission.

Haemopoietic regrowth after chemotherapy for acute leukaemia: an immunohistochemical study of bone marrow trephine biopsy specimens.

AIM: To analyse haemopoietic regrowth and residual disease in bone marrow trephine biopsy specimens after treatment for acute leukaemia, using immunohistochemical staining. METHODS: Biopsy specimens before and after treatment were studied from patients diagnosed as having acute myeloid or lymphoblastic leukaemia. Specimens after treatment encompassed periods from two to 56 weeks from the start of treatment. Routine haematoxylin and eosin and Giemsa stained sections were evaluated in association with immunostained preparations. A panel of antibodies was used, which reacts with epitopes showing restricted expression dependent on the lineage or maturation stage of cells. Results were evaluated in the light of clinical, peripheral blood, and marrow aspirate findings. RESULTS: The speed and sequence of regrowth of haemopoietic cells were more variable than expected. Immunostaining highlighted features of dysplasia after treatment and in some cases assisted detection of residual or relapsed leukaemia. Peripheral blood and aspirate cell counts reflected accurately the amount of regrowth, but not the dysplasia, seen in biopsy samples. Delayed regrowth was associated with complex individual factors. CONCLUSIONS: Morphological and immunohistochemical study of trephine biopsy specimens from patients treated for acute leukaemia provides information complementary to that obtained from peripheral blood and aspirated marrow. Variation in the timing and sequence of regrowth is highlighted. Immunostaining can aid in the detection of relapse or minimal residual leukaemia. The clinical relevance of dysplastic changes in biopsy specimens after treatment is uncertain, but such changes may persist for long periods.

Chronic myelomonocytic leukaemia associated with T cell receptor delta gene rearrangement.

Morphological, immunophenotypic, and genetic analyses were carried out on peripheral blood, bone marrow, and pharyngeal biopsy material from a patient with chronic myelomonocytic leukaemia (CMML). Morphological analysis of bone marrow was diagnostic of CMML; immunophenotypic analysis of peripheral blood and bone marrow were negative for B and T cell antigens, and immunochemistry performed on the pharyngeal extramedullary infiltrate showed the presence of large monocytoid cells which stained positively for muramidase. Genotypic analysis, however, showed clonal rearrangement of the T cell receptor (TCR) delta chain gene, a marker of T cell or, less commonly, B cell lymphoid neoplasms. Other TCR genes, beta and gamma, were germline in all tissues examined. TCR delta is rearranged in precursor B cell and most T lymphoid neoplasms. A small proportion of cases (10%) of acute myeloid leukaemia (AML) also show rearrangement of the TCR delta gene. To date TCR delta rearrangement has not been described in CMML. The aberrant TCR delta rearrangement shown in this patient with CMML provides further evidence of the clonal nature of this disorder.

Unusual splenic sinusoidal iron overload in sickle cell/haemoglobin D-Punjab disease.

Sickle cell/haemoglobin D-Punjab disease is a disorder with similar clinical features to sickle cell anaemia. This report describes the case of an 11 year old boy with this disease who was treated with regular transfusions from infancy. He underwent splenectomy at the age of 10 years for hypersplenism. Histology of the spleen revealed a striking pattern of heavy sinusoidal endothelial iron loading, with only moderate uptake by macrophages. Possible explanations for this unusual distribution of iron include phagocytosis of sickled erythrocytes by sinusoidal endothelial cells or direct endothelial iron uptake via transferrin receptors. Transfusion programmes ameliorate the symptoms of sickle cell disease but the dangers of iron overload should always be remembered.

Microwave antigen retrieval in immunocytochemistry: a study of 80 antibodies.

AIMS: To evaluate the effect of microwave irradiation on the staining quality of a range of commonly used primary antibodies in archival, formalin fixed, paraffin wax embedded material, with emphasis on antibodies that have previously worked successfully only on frozen tissue. METHODS: Immunocytochemistry (streptavidin-biotin complex technique) was performed on histological sections of a range of normal and pathological tissues, after varying treatment with microwave irradiation. The staining quality of each antibody was compared with that achieved without prior treatment of the sections or after enzyme predigestion. RESULTS: Microwave irradiation permitted successful immunostaining with 20 antibodies that stained only frozen tissues before. The staining characteristics of 21 antibodies that were already known to stain formalin fixed, paraffin wax embedded material were improved. Another 39 antibodies did not show enhanced staining with microwave irradiation. The method preserves tissue morphology and produces more consistent staining than that achieved by enzyme predigestion with many antibodies. Microwave irradiation may also allow some primary antibodies to be used at higher working dilutions. The citrate buffer used in this study avoids the necessity of exposure to heavy metal salts. CONCLUSIONS: Microwave antigen retrieval represents an important technical advance within immunocytochemistry that will greatly increase the range of antibodies which can be used to study formalin fixed, paraffin wax embedded tissues.

A new in vivo and in vitro B cell lymphoma model, pi-BCL1.

We report a new variant of the BCL1 syngeneic mouse B-cell lymphoma model, which we have called pi-BCL1. pi-BCL1 can be established as a syngeneic tumor in BALB/c mice. Tumors can be removed, prepared and easily grown in liquid culture and subsequently transferred back successfully as syngeneic tumors. As a syngeneic tumor pi-BCL1 behave more like a lymphoma with solid tumor masses, than a chronic lymphocytic leukaemia of the original BCL1 model. The immunophenotype and the growth characteristics of the pi-BCL1 and BCL1 tumors appear very similar. Cytologically, pi-BCL1 appears to be a transformation from a small lymphocytic lymphoma to a more diffuse large cell centroblast-like higher-grade lymphoma. We are not aware of any previous reports of such transformation events in a syngeneic animal model of B cell lymphoma. We believe pi-BCL1 provides a useful new tool for the study of B cell lymphoma in vitro and in vivo and enables reduced numbers of tumor passage in mice.

The mammalian zona pellucida: its biochemistry, immunochemistry, molecular biology, and developmental expression.

Many studies of the molecular and biochemical aspects of mammalian fertilization have focused on the interaction of the spermatozoa with the zona pellucida (ZP). The zona pellucida, a unique extracellular matrix surrounding the mammalian oocyte, is formed during ovarian follicular development. Following ovulation of the mature ovum, the spermatozoa must bind to and penetrate this matrix before the fertilization process is completed and the male and female genetic information combine. Although numerous models for this interaction have been proposed, the complete process has yet to be elucidated. The precise mechanisms by which these interactions occur also vary markedly among different mammalian species, making it more difficult to establish a unified model. To a great extent, the study of the molecules involved in these interactions have been limited because small numbers of female gametes are available for these studies. The recent development of techniques to isolate large numbers of zonae pellucidae as well as advances in immunological and molecular biology techniques have permitted the detailed characterization of ZP proteins. Although there is a paucity of information on the post-translational modification and extracellular processing of these molecules which result in matrix formation, a number of properties have been elucidated allowing better correlation between the structure and function of different ZP proteins among species. This review reflects these studies in relation to protein nomenclature and the molecular complexity of ZP antigens.

Quantitation of cyclin D1 over-expression using competitive fluorescent reverse transcription polymerase chain reaction: a tool for the differential diagnosis of mantle cell lymphoma.

Mantle cell lymphoma is characterized by the presence of the t(11;14)(q13;q32) translocation that causes over-expression of the BCL-1 gene and consequent overproduction of its gene product cyclin D1. We have developed a competitive fluorescent reverse transcription polymerase chain reaction assay for the detection and semiquantitation of cyclin D1 over-expression. Using this assay a definitive ratio of the expression of cyclin D1 to cyclins D2 and D3 can be determined, provided good quality RNA is available. A single upstream primer derived from a consensus sequence found in cyclins D1, D2, and D3 was labeled at the 5' end using a fluorescent dye. Downstream primers specific to cyclins D1 and D2 were designed and used in conjunction with a previously published D3 specific primer. The fluorescently labeled PCR products were separated by electrophoresis using an ABI 377 DNA sequencer. Fluorescence emitted from each product was used to determine the ratio of expression of cyclin D1 to D2 and D3 by assigning a dosage quotient [D1/(D2+D3)]. The mean dosage quotient recorded from samples representing 29 non-MCL patients was 0.03 (SD +/- 0.03), the maximum value being 0.11. Samples from eight patients with a diagnosis of MCL generated values greater than 2. Calculation of a dosage quotient using this competitive fluorescent reverse transcription polymerase chain reaction assay allows unequivocal identification of patients with over-expression of cyclin D1, providing a new tool for the differential diagnosis of MCL.

Influence of husbandry on the transfer of radiocaesium from feed to milk during the winter that followed the Chernobyl reactor accident.

The release of activity from the Chernobyl nuclear reactor resulted in deposition of radionuclides throughout the UK in early May 1986. Since that time, the transfer of radiocaesium from feed to milk has been followed at two farms that differ in both location and husbandry practice. This paper concerns the winter of 1986/87, when activity concentrations in milk increased because of the consumption of silage prepared earlier in the year. Silage-to-milk transfer coefficients have been estimated which suggest that, when incorporated into prepared silage, radiocaesium from Chernobyl is less available for transfer to cows' milk than soluble caesium-134 applied directly onto pasture. The measured activity concentrations in milk have been compared with those predicted by the NRPB model FARMLAND; despite differences between the husbandry practice assumed in the model and those observed in practice, the model provides an adequate radiological assessment of the feed-cow-milk pathway after an accidental release of radioactivity.

Transfer of radionuclides to vegetable and other crops grown on land reclaimed from the sea.

An area of reclaimed land on the Lancashire coast has been used to grow a wide range of crops to provide data on transfer parameters of radionuclides in foodchains when the activity is almost entirely of marine origin. Activity concentrations in the foodstuffs were low and not of radiological significance. However, meaningful results could be obtained if large sample sizes were employed. This paper sets out the methodology applied to a substantial field investigation of transfer to vegetable crops. The large sample sizes could be accommodated adequately with only minor modifications to established analytical procedures. The results of the study are discussed briefly. Since the growing conditions were virtually identical for each crop, comparisons of transfer factors between the different crops should therefore be valid. For some radionuclides, notably 239,240Pu, 241Am and 99Tc, the work has added significantly to the data that are presently available. For most of the radionuclides studied, uptake by crops could be adequately predicted using the parameter values currently used in generic assessments, but for 99Tc, lower values would be more appropriate.