Investigation of clonal involvement of myeloid cells in Philadelphia-positive and high hyperdiploid acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) with a high hyperdiploid clone has a good prognosis for both childhood and adult patients while patients with Philadelphia-positive (Ph) ALL do badly at all age groups. It has been suggested that different responses to treatment might be related to the cell of origin of the leukemia with 'stem cell' cases responding less well than those arising in a lymphoid committed progenitor cell. The clonal involvement of different cell lineages in 12 patients with acute lymphoblastic leukemia has been examined by applying fluorescence in situ hybridization (FISH) to detect chromosomal abnormalities in bone marrow cells previously identified by morphology and/or immunology. The karyotype of the malignant clone was either high hyperdiploid or Philadelphia translocation (Ph) positive with a breakpoint in the minor breakpoint cluster region of the BCRgene (m-BCR) or in the major breakpoint cluster region of the BCR gene (M-BCR). The high hyperdiploid clone, in each case, was found in cells of the B-lymphoid (CD19+) lineage but not in T cells (CD3+) or in cells of the myeloid (CD13+) or erythroid (glycophorin A+) lineages, indicative of a lymphoid committed progenitor cell. Heterogeneity of lineage involvement was found in Ph+ ALL: the m-BCR Ph+ clone was found in lymphoid/blast cells but not in neutrophils or eosinophils. In contrast both M-BCR Ph+ clones were detected in myeloid as well as lymphoid lineages, indicative of a stem cell origin.

A simple, robust, validated and highly predictive index for the determination of risk-directed therapy in acute myeloid leukaemia derived from the MRC AML 10 trial. United Kingdom Medical Research Council's Adult and Childhood Leukaemia Working Parties

Data on 1711 patients, aged up to 55 years, in the MRC AML 10 trial were used to create a prognostic index for use in risk-directed therapy decision making for younger patients with acute myeloid leukaemia (AML). Two parameters, response after course 1 and cytogenetics, were strongly predictive of outcome. For patients with complete remission, partial remission and resistant disease, 5-year survival from the start of course 2 was 53%, 44% and 22% and relapse rates were 46%, 48% and 69% respectively, and for patients with favourable, intermediate and adverse karyotypic abnormalities, survival was 72%, 43% and 17% and relapse rates were 34%, 51% and 75% respectively (all P < 0.0001). Patients with FAB type M3 but no cytogenetic t(15;17) also had a low relapse rate (29%). These three factors were combined to give three risk groups: good (favourable karyotype or M3, irrespective of response status or presence of additional abnormalities), standard (neither good nor poor), poor (adverse karyotype or resistant disease, and no good-risk features). Survival for these three groups was 70%, 48% and 15% respectively and relapse rates were 33%. 50% and 78% (both P < 0.0001). The index is simple (based on just three parameters), robust (derived from 1711 patients), highly discriminatory (55% survival difference between good and poor risk) and validated, so can be applied in the clinical setting to assist with therapeutic decisions as in the current AML 12 trial.

Fluorescence in situ hybridization analysis of masked (8;21)(q22;q22) translocations

The translocation (8;21)(q22;q22) is associated with acute myeloblastic leukemia (AML M2). The accurate detection of this chromosomal rearrangement is vital due to its association with a favorable prognosis. Variant translocations exist; these may be hidden within an unusual or complex karyotype. In such cases, it is often difficult to confirm the presence of t(8;21)(q22;q22) by conventional cytogenetic analysis alone. The molecular detection of the AML1/ETO fusion gene is possible by reverse transcriptase polymerase chain reaction (RT-PCR) or dual-color fluorescence in situ hybridization (FISH) using probes specific for AML1 and ETO. Four cases of AML M2, with unusual or complex structural chromosomal abnormalities, without cytogenetic evidence of the classical t(8;21)(q22;q22), were studied by FISH. Two were AML1/ETO positive by RT-PCR, one showed a rearrangement by AML1 by Southern analysis, and the fourth had morphological features characteristic of t(8;21). The FISH results showed a co-localization of one AML1 and one ETO signal in interphase and metaphase nuclei in all four cases, demonstrating the presence of variant t(8;21)(q22;q22) rearrangements. Therefore, FISH analysis with the AML1 and ETO probes is extremely valuable, in cases of AML M2, because of its ability to reveal masked t(8;21)(q22;q22) translocations and thus quickly confirm the diagnosis, allowing patients to be assigned to the correct risk group in terms of treatment.

Abnormal cytogenetic clones in patients with aplastic anaemia: response to immunosuppressive therapy

We report the response to immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporin or oxymetholone in 13 cases of aplastic anaemia (AA) with an abnormal cytogenetic clone detected at or sometime after diagnosis. Blood and bone marrow examination showed no distinctive morphological features of myelodysplasia (MDS) at diagnosis. Haematological response occurred promptly in eight cases; the remainder responded after additional immunosuppression with or without oxymetholone. Three patients had a late relapse of AA, treated successfully by allogeneic bone marrow transplantation in one; the others responded to oxymetholone. Transformation to MDS or acute leukaemia was not observed after a median follow-up of 4.1 years (range 1.2-11.2). In four patients the cytogenetic clone disappeared after treatment.

The importance of cytogenetics and associated molecular techniques in the management of patients with leukaemia

The cytogenetic analysis of haematological malignancies plays a major role in diagnosis. A large number of non-random chromosomal abnormalities are associated with specific types of leukaemia. Often, the cytogenetic result provides the definitive diagnosis. The recent developments in molecular cytogenetic technologies, in association with conventional cytogenetic analysis, have improved the accuracy of the results and led to the finding of new chromosomal abnormalities in leukaemia. Patients may be monitored by cytogenetics, molecular techniques and/or fluorescence in situ hybridization (FISH) during the course of their management, for evidence of minimal residual disease. These techniques also provide a useful method for monitoring patients following bone marrow transplantation, particularly when the patient and the donor are of the opposite sex. The cytogenetic result is an independent prognostic indicator, with certain karyotypes associated with a good prognosis, although others indicate a poor outcome.

Abnormalities of the ETV6 gene occur in the majority of patients with aberrations of the short arm of chromosome 12: a combined PCR and Southern blotting analysis

Involvement of the ETV6 gene, located at 12p13, has been investigated in 20 patients with an abnormality of the short arm of chromosome 12 (abn 12p) detected cytogenetically. Patients in the study had c/pre-B acute lymphoblastic leukemia (ALL) (nine children and three adults), T-ALL (three adults), acute myeloid leukemia (AML) (two adults), biphenotypic acute leukemia (Bip-L) (one adult), myelodysplasia (MDS) (one adult) and chronic myelomonocytic leukemia (CMML) (one child). Abnormalities of 12p comprised deleted (del)(12p) alone (seven cases), add(12p) alone (seven cases), del(12p) and add(12p) (one case) and balanced translocations of 12p to 1p13, 1q31, 10q11, 14q11 and 15q15 (one case of each). A novel, exon-specific RT-PCR assay identified breakpoints in ETV6 in nine of 19 cases, and showed breakpoints in intron 5 (seven cases of children with c-ALL), in intron 4 (in one adult with Bip-L) and in intron 2 (in one adult with AML). RT-PCR for the ETV6/AMLI fusion (tested in 19 cases) was positive using standard primers in five cases (four of which had shown rearrangements in intron 5) and occurred as a variant fusion in a sixth case (also positive for a rearrangement in intron 5) using 3' RACE PCR. Southern blotting confirmed rearrangements in intron 5 in the five cases available for analysis and revealed a rearrangement in intron 5 in one of 10 cases with no evidence of intron 5 involvement by RT-PCR. Rearrangements in intron 5 of ETV6 were found in eight of nine cases of children with c-ALL of which six carried the ETV6/AMLI fusion. Heterozygosity within intron 5 (revealed by the genomic probe B1) was found in seven of 11 cases tested. Deletion of one allele was indicated in three cases with del(12p) and one case with add(12p). This study, using a combination of ETV6 exon-specific RT-PCR, RT-PCR for ETV6/AMLI and Southern blotting has shown that rearrangement and/or deletion of ETV6 may occur in up to 70% of patients with abn 12p. Furthermore, 90% of children in this study with an abn 12p and c-ALL, carried a rearrangement of ETV6 in intron 5.

Ten novel 11q23 chromosomal partner sites. European 11q23 Workshop participants

The MLL gene located at 11q23 has been described as a 'promiscuous' gene due its involvement with a large number of genetic partners. The EU Concerted Action Workshop on 11q23 provided 550 cases for study of which 82 showed abnormalities which did not involve the established translocations or deletion of 11q23. In these 'other' cases, which included inversions and duplications, 11q23 was found to be involved with 25 chromosome partners of which 10 had not been previously reported. These were 1q31, 4p11, 6q13, 8q21, 10q22, 10q25, 11q11, 11q21, 13q34 and 18q23. This study demonstrated the value of the Workshop, in confirming the diversity of chromosomal partner sites involved with 11q23 and in the identification of new partners.

A decision analytic approach to commissioning ambulance cardiac services

The paper discusses how a decision analytic framework has been used by an English health authority in relation to the commissioning of ambulance cardiac services. Strategies for the management by ambulance personnel of victims of cardiac arrest and persons with acute chest pain of cardiac origin were modelled in a decision-event tree, and a bibliographic database established. The international research literature prior to 1997 was searched in order to derive probability values for the tree. However, after checking whether the subgroupings of results in the papers were in accordance with the variables in the tree, the number of useful papers on acute chest pain was found to be only two. In the almost complete absence of information--even from small observational studies--on the management of the great majority of patients with cardiac symptoms transported by ambulance, the local ambulance service and the main providers of hospital services in the district are now collaborating in field studies of cardiac care in order to improve the inputs into the model.

La cage aux fold: asymmetry in the crystal structure of GroEL-GroES-(ADP)7

The structure of the molecular chaperone GroEL from Escherichia coli in complex with GroES and seven ADP molecules has recently been reported to 3 A resolution. The structure illustrates how the cavity of GroEL is converted from a hydrophobic environment, suitable for binding unfolded polypeptides, to a much larger hydrophilic environment suitable for refolding proteins.

A chromosome 14q11/TCR alpha/delta specific yeast artificial chromosome improves the detection rate and characterization of chromosome abnormalities in T-lymphoproliferative disorders

The rate of detection of chromosome abnormalities in T-cell proliferations is lower than that observed in B-cell malignancies. The former frequently involve the TCR alpha/delta locus at chromosome band 14q11. We have identified a YAC encompassing 70% of the TCR alpha/delta locus, which has been used as a fluorescence in situ hybridization probe to detect chromosome rearrangements involving 14q11, both at metaphase and within interphase nuclei, in patients with a variety of T-lymphoproliferative disorders. Its use allowed detection of previously unsuspected TCR alpha/delta rearrangements in 4/13 (30%) immature T-lineage acute leukemias, including two t(10;14) and 2 minor inversion 14s. It also clarified interpretation of complex chromosome 14 abnormalities in mature T-cell proliferations (T-prolymphocytic leukemia and ataxia telangiectasia). Use of this probe will aid the detection and characterization of abnormalities involving the TCR alpha/delta locus, particularly in cases with normal or complex karyotypes and in those proliferations for which mitoses are difficult to obtain.

Autografting in Philadelphia (Ph)+ chronic myeloid leukaemia using cultured marrow: an update of a pilot study

Incubation of CML marrow in long-term culture (LTC) conditions may result in selection of normal (Ph-) LTC-initiating cells (LTC-IC) as early as 10 days, and in production of Ph- clonogenic cells and mature end cells within 5 weeks. This was the rationale for using marrow cells from 10-day-old LTC to autograft nine chronic phase CML patients, ineligible for HLA-matched sibling donor transplant, and who were selected on the basis of a pre-transplant screening LTC test. Of the transplanted patients three died; two of graft failure and one of therapy-related toxicity with 97% Ph- cells 16 months following the autograft. The reconstituting haemopoietic cells in the seven engrafted patients were 100% Ph- in four, > or = 90% Ph- in two and 71% Ph- in the seventh, with a duration of complete cytogenetic response of 6-12 months. Three patients reverted to chronic phase and 100% Ph+ haemopoiesis 27-36 months post-autograft. The other three patients remain in continuous haematological remission with 22% Ph- cells in one and complete cytogenetic remission in the other two 3-4 years post-autograft. IFN therapy was generally introduced on the first evidence of recurrence of Ph+ cells or of cytogenetic deterioration. Further strategies to modulate immune surveillance in vivo may improve the outcome of cultured marrow autografts which give an initial and rather prolonged bias towards Ph- haemopoiesis.

Crystal structure of the nucleotide exchange factor GrpE bound to the ATPase domain of the molecular chaperone DnaK

The crystal structure of the adenine nucleotide exchange factor GrpE in complex with the adenosine triphosphatase (ATPase) domain of Escherichia coli DnaK [heat shock protein 70 (Hsp70)] was determined at 2.8 angstrom resolution. A dimer of GrpE binds asymmetrically to a single molecule of DnaK. The structure of the nucleotide-free ATPase domain in complex with GrpE resembles closely that of the nucleotide-bound mammalian Hsp70 homolog, except for an outward rotation of one of the subdomains of the protein. This conformational change is not consistent with tight nucleotide binding. Two long alpha helices extend away from the GrpE dimer and suggest a role for GrpE in peptide release from DnaK.

Analysis of chromosome 6 deletions in lymphoid malignancies provides evidence for a region of minimal deletion within a 2-megabase segment of 6q21

Fluorescence in situ hybridization has been used to define deletion breakpoints within chromosome bands 6q16-21 in cases of lymphoid malignancy. Previous evidence suggested that the region might contain a tumour-suppressor gene. Six yeast artificial chromosome probes, each selected using a single marker, were localized to 6q16-21 and the following order was confirmed; D6S330-D6S283-D6S301-D6S447-D6S246-FYN+ ++. Of 32 cases of lymphoid malignancy, 30 showed deletion of D6S246 and, in the two cases in which D6S246 was retained, the adjacent marker, D6S447, was deleted. These observations imply that a region of minimal deletion is located within a 2-megabase segment of 6q21, between D6S447 and D6S246, providing a candidate region for the location of a tumour-suppressor gene.

Using antibiotic concentrations in middle ear fluid to predict potential clinical efficacy

BACKGROUND

The effectiveness of an antibiotic in eradicating an infection within an anatomic compartment is related to both its availability (penetration) and the susceptibility of the causative pathogen. Antimicrobial penetration can be assessed by measuring concentrations in serum or tissue. However, to assess antibiotic effectiveness in the treatment of otitis media, both antibiotic concentrations and pathogen profiles in middle ear fluid (MEF) should be considered. Tympanocentesis is required to access fluid in the middle ear compartment. This paper considers data on (MEF) antibiotic concentrations obtained with this procedure.

METHODS

Data on MEF antibiotic concentrations were considered in relation to the antibiotic susceptibility profiles of the more common otitis media pathogens.

RESULTS

Amoxicillin reaches MEF concentrations that exceed MICs for penicillin-susceptible and penicillin relatively resistant Streptococcus pneumoniae, but not for beta-lactamase-producing Haemophilus influenzae. Several beta-lactamase-stable drugs, e.g. cefixime and amoxicillin/clavulanate, however, achieve MEF concentrations that easily exceed their respective MIC90s for both beta-lactamase-producing and nonproducing H. influenzae but at ordinary doses may not exceed MIC90s for penicillin relatively resistant S. pneumoniae.

CONCLUSION

Ongoing observation of organisms and their antibiotic resistance patterns in patients failing initial therapy of acute otitis media indicate that stability to beta-lactamase remains an essential quality for effective second line therapies. However, when possible tympanocentesis with culture is the ideal method of targeting specific therapy for patients failing multiple consecutive antibiotic regimens.

Evaluation of cytogenetic conversion to Ph- haemopoiesis in long-term bone marrow culture for patients with chronic myeloid leukaemia on conventional hydroxyurea therapy, on pulse high-dose hydroxyurea and on interferon-alpha

Long-term bone marrow culture (LTBMC) has been used successfully in autologous transplantation in chronic myeloid leukaemia (CML). However, variation between patients in the recovery of Ph- cells in culture limits the application of this procedure to a minority. Treatment that effectively reduces in vivo tumour burden prior to initiation of LTBMC may improve the selection of Ph- cells in culture. To test this hypothesis we evaluated the frequency and degree of cytogenetic conversion to Ph- haemopoiesis in LTBMC from four independent groups of CML patients: Untreated (n = 19); conventional dosage of hydroxyurea (HU) (n = 10); pulse high-dose HU (P-HU) (n = 22) and interferon (IFN)-alpha (n = 12). In this study IFN-alpha therapy resulted in a significantly higher incidence of patients with detectable Ph- clonogenic cells in the marrow (P = 0.01) and with > or = 50% Ph- haemopoiesis in LTBMC as compared to newly diagnosed patients (P = 0.05). Also, sequential culture studies undertaken in 14 CML patients at diagnosis and following the start of pulse highdose HU therapy showed that in eight patients the average proportion of Ph- metaphases detected in LTBMC substantially increased from 1.7% (range 0-7) at diagnosis to levels of 71% (range 14-100) after treatment. Therefore we conclude that the use of IFN or pulse high-dose HU in early stage disease appears to create an opportunity to harvest the marrow for long-term culture (LTC) purging with reduced leukaaemic burden.

Effect of antibody alone and combined with acyclovir on neonatal herpes simplex virus infection in guinea pigs

Neonatal herpes simplex virus (HSV) infection produces severe disease with unacceptable morbidity and mortality with current antiviral therapies. The effect of therapy with passive anti-HSV antibody and acyclovir was evaluated using a guinea pig model of neonatal HSV. Newborn animals were inoculated intranasally and treated with acyclovir (60 mg/kg/day) or antibody (or both), beginning on days 0, 2, or 3 after HSV-2 inoculation. Acyclovir alone was effective only when begun on day 0, and antibody alone was effective when begun on or before day 2. Only combination therapy was effective on day 3, reducing mortality from 82% (14/17) in controls to 44% (7/16; P < .05). Combined therapy also significantly reduced the duration of skin, eye, and mouth disease and respiratory symptoms but not recurrent disease. These data suggest that addition of antibody therapy to acyclovir may improve the outcome of neonatal HSV disease.

Refined solution structure and dynamics of the DNA-binding domain of the heat shock factor from Kluyveromyces lactis

The solution structure of the 92 residue (11 kDa) winged helix-turn-helix DNA-binding domain from the kluyveromyces lactis heat shock factor was refined using a total of 932 NOE, 35 phi, 25 chi 1, 5 chi 2 and 44 hydrogen bond restraints. The overall root-mean-square deviation for structured regions was 0.75(+/- 0.15) A. The three-helix bundle and four-stranded beta-sheet are well defined with rmsd of 0.53(+/- 0.10) A and 0.60(+/- 0.17) A, respectively. Helix H2 is underwound and bent near Pro45. The angle between helix H2 and the proposed recognition helix H3 is 96(+/- 6) degrees. Detailed comparisons are made with the X-ray structure of this protein as well as other structural studies on HSF. Overall, the results are consistent with the earlier studies. Differences are related to protein-protein interactions in the crystal and dynamics in solution. Backbone dynamics was investigated via 15N relaxation. The average R1, R2 and NOE values for residues in segments of secondary structure were 1.9(+/- 0.9) s-1, 7.8(+/- 0.9) s-1 and 0.81(+/- 0.05), respectively. The correlation time based on these data was 5.6(+/- 0.4) ns. Motional order parameters were calculated by fitting the relaxation data to one of three models. Low-order parameters were found for residues that comprise the turn between helices H2 and H3 (residues Lys49 to Phe53), and most strikingly, the 16 residue wing (residues Val68 to Arg83). These data are consistent with the lack of long-range NOEs identified in these regions. The data provide a basis for comparison with results of the protein-DNA complex. The relationship between structure and function is discussed.

Reduced congenital cytomegalovirus (CMV) infection after maternal immunization with a guinea pig CMV glycoprotein before gestational primary CMV infection in the guinea pig model

This study evaluated the effects of subunit guinea pig (GP) cytomegalovirus (CMV) immunization on congenital infection. Two 25-micrograms doses of an abundant GPCMV glycoprotein, the gp60-90 complex, plus adjuvant to GPs before pregnancy produced virus-specific humoral (neutralizing and ELISA) and cellular (proliferative and delayed type hypersensitivity) responses. Viral challenge before midgestation resulted in shorter maternal viremia in immunized than in unimmunized dams (3 vs. 17 days). Litters of immunized dams had reduced organ involvement and rates of congenital infection (48% vs. 18%) and increased mean birth weights (74 vs. 99 g). Amplification of DNA extracted from pup blood or organs with primers from the gB gene of GPCMV revealed congenital infection in some pups without detectable CMV by classic culture techniques. These data suggest that induction of preconception immunity to CMV by vaccine could be useful in reducing both the incidence and severity of congenital CMV disease.

Neonatal herpes simplex virus (HSV) infections

Prevention remains the best form of "treatment" of neonatal HSV infection. Prompt work-up and initiation of antiviral therapy provide the best outcome once infection has occurred. It is critical that practitioners be aware of the urgency of initiation of therapy as well as the signs/symptoms of maternal and neonatal HSV infection.