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Biomedical subjects

F Katz

Publications and source records attributed to F Katz.

At least 19 recordsLinked to original sources

Six steps to compliance for small practices.

Developing a compliance plan for a small physician practice can be easier than you'd think. The author offers six things HIM professionals can do to ensure a practice's compliance.

Documentation↗

Clonality analysis suggests that early-onset acute lymphoblastic leukaemia is of single-cell origin and implies no major role for germ cell mutations in parents.

Childhood leukaemia presenting at a young age has been suspected of resulting from a leukaemogenic mutation in parental germ cells, either spontaneously or due to the exposure of a parent to leukaemogenic environmental hazards, particularly ionizing radiation. Mathematical modelling of leukaemogenesis suggests that any such patient would be especially prone to multiple independent leukaemogenic events leading to multiclonality in terms of cell of origin (analogous to bilaterality in familial retinoblastoma). To test this hypothesis we have carried out a search for multiclonal leukaemogenesis in infant and childhood acute lymphoblastic leukaemia (ALL). We used a polymerase chain reaction-based analysis of the X-linked monoamine oxidase A (MAOA) gene locus to study the clonality of marrow samples obtained from female paediatric ALL patients at the time of disease presentation. We obtained presentation samples from 102 patients of whom 72 were found to be informative at the MAOA locus. These included 20 infant leukaemias (< 1 year at diagnosis). Sixty-six samples were found to be unequivocally monoclonal while the remaining six could not, with certainty, be assigned a clonal origin. We also obtained bone marrow aspirates at first relapse as well as at presentation from eight patients. In each case the same pattern of X-linked allelic inactivation was observed at both time points of the course of the disease. No evidence was found for leukaemic multiclonality in any age group at presentation or for leukaemic 'clone-switching' in relapse. These findings suggest that both infant and childhood ALL is of single-cell origin and implies that leukaemic predisposition resulting from germ cell mutation is unlikely to have a major role in their pathogenesis.

Adolescent↗

Absence of expression of the Wiskott-Aldrich syndrome protein in peripheral blood cells of Wiskott-Aldrich syndrome patients.

Wiskott-Aldrich syndrome (WAS) is an X-linked primary immunodeficiency that is usually associated with thrombocytopenia and eczema. The very variable phenotype of WAS results from defects in the WAS protein (WASP), the function of which is not well understood. In many cases causative mutations have now been identified in the WAS gene. Attempts have been made to correlate the nature of the mutations with the severity of the disease. In this study we investigated mutations in 13 patients with WAS and analyzed the expression of WASP in patient blood samples by immunoblot analysis. We found that despite extensive variation in the nature of the mutations in patients with severe WAS symptoms, none express the protein. However, in 1 patient with a mild clinical phenotype WASP expression was detected. Such an analysis could be used as an initial screening procedure for the diagnosis of WAS prior to genotypic analysis.

Base Sequence↗

B-cell-negative severe combined immunodeficiency associated with a common gamma chain mutation.

Severe combined immunodeficiency (SCID) is caused by a variety of underlying defects. Approximately 40% of cases are thought to be of the X-linked type (SCIDX1), which is phenotypically characterised by the absence, or very low numbers, of T cells, but normal or even high B cell numbers. The gene responsible for SCIDX1 is that coding for the common gamma chain (gamma c), a component of multiple cytokine receptors. Mutations in this gene have been demonstrated in a large number of boys affected by typical SCIDX1. We describe a sporadic case of a boy who had SCID with absent B cells and absent T cells, but in whom a mutation in the gamma c gene has been demonstrated. In the absence of a typical X-linked pedigree, the phenotype in this boy suggested an autosomal recessive form of SCID and the family would usually have been counselled accordingly. This family raises the question of the true frequency of SCIDX1 amongst sporadic male cases of SCID and highlights the need to screen these boys for gamma chain mutations.

Antigens, CD↗

Mutation analysis in CD40 ligand deficiency leading to X-linked hypogammaglobulinemia with hyper IgM syndrome.

Mutations in the gene encoding CD40 ligand have been shown to be the cause of X-linked hypogammaglobulinemia with hyper IgM (HIGM1). We have used the technique of single strand conformational polymorphism (SSCP) analysis to screen for mutations in this gene in affected boys from nineteen unrelated families. Sixteen novel mutations were identified in patients, comprising six patients with single base substitutions, two patients with single base insertions, six patients with deletions ranging from one to seven bases and two patients with large deletions at the 5' end of the gene. These mutations were distributed throughout the gene SSCP band shifts and/or alterations in restriction enzyme digestion sites could be used for unambiguous determination of carrier status in at-risk female relatives of most of the affected boys and, in some cases, prenatal diagnosis also can be offered.

Agammaglobulinemia↗

Improving performance with clinical decision support.

BACKGROUND: CADU/CIS (Clinical and Administrative Decision-support Utility and Clinical Information System) is a clinical decision-support workstation that allows large volumes of clinical information systems data to be analyzed in a timely and user-friendly fashion. CARE PROCESS MEASUREMENT: For any given disease, subgroups of patients are identified, and automated, customized "clinical pathways" are generated. For each subgroup, the best practice norms for use of test and therapies are identified. Practice style variations are then compared to outcomes to focus inquiry on decisions that significantly affect outcomes. CASE STUDY: INTESTINAL OBSTRUCTION: Graduate Health Systems, a multisite integrated provider in the Philadelphia area, has used CADU/CIS to improve quality problems, reduce treatment-intensity variations, and improve clinical participation in care process evaluation and decision making. A task force selected intestinal obstruction without hernia as its first study because of the related high-volume and high-morbidity complications. Use of a ten-step method for clinical performance improvement showed that the intravenous administration of unnecessary fluids to 104 patients with intestinal obstruction induced congestive heart failure (CHF) in 5 patients. Task force members and other practicing physicians are now developing guidelines and other interventions aimed at fluid use. Indeed, the task force used CADU/CIS to identify an additional 250 patients in one year whose conditions were complicated by CHF. CONCLUSION: A clinical decision support tool can be instrumental in detecting problems with important clinical and economic implications, identifying their important underlying causes, tracking the associated tests and therapies, and monitoring interventions.

Aged↗

The t(7;11)(p15;p15) translocation in acute myeloid leukaemia fuses the genes for nucleoporin NUP98 and class I homeoprotein HOXA9.

The t(7;11)(p15;p15) translocation is a recurrent chromosomal abnormality associated primarily with acute myeloid leukaemia (FAB M2 and M4). We present here the molecular definition of this translocation. On chromosome 7 positional cloning revealed the consistent rearrangement of the HOXA9 gene, which encodes a class I homeodomain protein potentially involved in myeloid differentiation. On chromosome 11 the translocation targets the human homologue of NUP98, a member of the GLFG nucleoporin family. Chimaeric messages spliced over the breakpoint fuse the GLFG repeat domains of NUP98 in-frame to the HOXA9 homeobox. The predicted NUP98-HOXA9 fusion protein may promote leukaemogenesis through inhibition of HOXA9-mediated terminal differentiation and/or aberrant nucleocytoplasmic transport.

Amino Acid Sequence↗

CD40 ligand deficiency presenting as unresponsive neutropenia.

A male child presented with recurrent respiratory infections, otitis media, and oral ulceration and was found to be neutropenic. Investigations showed hypogammaglobulinaemia with normal serum IgM and a novel deletion in the gene for CD40 ligand on his X chromosome. Intravenous gammaglobulin did not lead to resolution of his neutropenia; G-CSF was also necessary.

Agammaglobulinemia↗

Proving the link between outcomes and resource utilization.

Medical practice profiling is a popular way of helping to reduce variation in resource utilization among providers in managed care organizations. Usually, these programs take into account severity of illness, patient demographics, and so forth, but rarely are clinical practice patterns linked with outcome. The authors offer information about an information system-based program that attempts to do just that.

Critical Pathways↗

A polymerase chain reaction study of the stability of Ig heavy-chain and T-cell receptor delta gene rearrangements between presentation and relapse of childhood B-lineage acute lymphoblastic leukemia.

Ig heavy-chain (IgH) and partial V delta 2-D delta 3 T-cell receptor (TCR) gene rearrangements were investigated, by polymerase chain reaction (PCR) amplification and sequence analysis, in 52 patients at presentation and first relapse and in 14 at both first and second relapse of B-lineage acute lymphoblastic leukemia. In combination, these techniques amplified one or more clonal markers at presentation in 90% of patients (IgH-PCR, 75%; V delta 2-D delta 3-PCR, 46%; both, 33%). Changes in the pattern of amplification between presentation and first relapse were seen in 31% of patients positive by IgH-PCR at presentation and in 25% of those positive by TCR delta-PCR. Only 3 patients showed complete change in their rearrangements, which is suggestive of relapse with a new clone. Furthermore, despite the high reported rates of oligoclonality and clonal evolution at the IgH locus, the results presented show that false-negative minimal residual disease (MRD) detection can be avoided by designing D-N-J probes to all presentation rearrangements. Using a PCR approach for both gene markers, false-negative testing because of clonal evolution would have only occurred in 3 (8%) of the IgH-positive patients, in contrast to 5 (21%) of V delta 2-D delta 3-positive patients. Combining these two systems increases the proportion of patients open to study to 90%, allows comparative studies of the sensitive of the two methods, and reduces the rate of false-negative assessment of MRD caused by clonal evolution to less than 10%. We conclude that large prospective PCR studies of MRD detection should examine gene rearrangements at multiple loci to maximize their applicability and to minimize false-negative relapse prediction.

Adolescent↗

PCR assessment of bone marrow status in 'isolated' extramedullary relapse of childhood B-precursor acute lymphoblastic leukaemia.

Approximately one-third of first relapses of childhood ALL occur at an extramedullary site without morphological evidence of bone marrow disease. However, the high incidence of subsequent medullary relapse in these cases strongly suggests that leukaemia is present at submicroscopic levels at the time of 'isolated' relapse. PCR analysis of immunoglobulin heavy chain (IgH) and T-cell receptor (TCR) gene rearrangements now allows detection of leukaemia at levels as low as 0.001%. We have therefore used this technique to reassess bone marrow status at morphologically isolated relapse in 13 children with B-lineage ALL (11 with off-treatment relapses, two on treatment). In 12 of these 13 patients marrow disease was detectable by PCR at the time of this relapse--in all cases at levels below the threshold of light microscopy. Where relapse occurred off-therapy this indicated re-emergence of disease. since MRD has never been detected by PCR at this stage in patients remaining in long-term remission. In both patients who relapsed on-therapy the level of MRD at the time of relapse represented an increase on that seen in their previous marrow sample. We conclude that re-emerging bone marrow disease can be detected in most cases of 'isolated' relapse when investigated by this highly sensitive technique. Our findings at a molecular level confirm a long-held clinical suspicion and indicate that full systemic re-induction as well as local therapy is obligatory for these children.

Adolescent↗

Trisomy X in a female member of a family with X linked severe combined immunodeficiency: implications for carrier diagnosis.

We describe a family affected by X linked severe combined immunodeficiency (SCIDX1) in which genetic prediction of carrier status was made using X chromosome inactivation studies together with limited genetic linkage analysis. Linkage studies in this family showed a confusing pattern of inheritance for the X chromosome. A female with a random pattern of X chromosome inactivation in her T cells appeared to have inherited an X chromosome with four recombinations within 10 cM. The odds of this happening in a single meiotic event make this an unlikely explanation. Data obtained from studying the X chromosomes of her two unaffected sons showed that this could be explained simply on the basis of her having inherited three alleles each of the relevant polymorphic DNA loci. We used fluorescent in situ hybridisation (FISH) to confirm that this person had inherited three complete X chromosomes. Thus, although the results from X chromosome inactivation analysis indicated that this subject was not a carrier of the affected chromosome, FISH and genetic linkage analysis showed clearly that the affected chromosome had been inherited. The implications of this finding for diagnosis of carrier status in this family and for other families with X linked inherited immunodeficiencies is discussed.

Chromosome Mapping↗

Characterisation of non-concordance in the T-cell receptor gamma chain genes at presentation and clinical relapse in acute lymphoblastic leukemia.

We have analysed the structure of the T-cell receptor gamma chain (TCRG) genes in a panel of biopsies taken from 24 patients with acute lymphoblastic leukemia (ALL) (13 cALL, one pre-B ALL, two null ALL and eight T-ALL) at presentation and at clinical relapse. In the majority of cases (18/24) the structure of these genes was concordant, but in a significant minority of cases (6/24) the TCRG genes were in a different conformation at different clinical stages. In three of these patients (one null ALL, two T-ALL) the clonal TCRG rearrangements detected at presentation were absent at relapse possibly as a result of clonal regression. In one other patient (cALL), the TCRG locus at relapse was rearranged to V genes which are located downstream of the V genes found in the presentation rearrangement. This indicates that the relapse leukemic clone is probably the result of clonal evolution. In two patients (one cALL, one T-ALL) there were no clonally dominant rearrangements of the TCRG genes at presentation, but evidence for clonal rearrangements at relapse, possibly as a result of clonal progression. The structure of the IgH genes were determined in four of the six patients with clonal changes in the TCRG genes and were found to be concordant. The changes in TCRG gene structure were not restricted to ALL of any one particular age group, phenotype or duration of first remission. These data indicate that the assignment of clonal specific markers based upon the sequence of TCRG rearrangements at presentation may not always be useful in the detection of minimal residual disease in ALL.

Adolescent↗

Leukaemia arising in donor cells following allogeneic bone marrow transplantation for beta thalassaemia demonstrated by immunological, DNA and molecular cytogenetic analysis.

Combined DNA analysis, molecular cytogenetic and immunological techniques have been used to identify the donor origin of common acute lymphoblastic leukaemia (cALL) which arose in a male patient with beta thalassaemia major, 5 years after an allogeneic bone marrow transplant from his HLA-matched sister. The necessity of using multiple techniques in this and similar cases is emphasized and the possible mechanisms for the development of donor leukaemia and the leukaemic transformation of donor cells are discussed.

Bone Marrow↗

Assessment of graft status following allogeneic bone marrow transplantation for haematological disorders in children using locus-specific minisatellite probes.

We have examined peripheral blood or bone marrow DNA following allogeneic bone marrow transplantation (BMT) in children suffering from a variety of haematological disorders. Using either locus-specific minisatellite probes separately or in combination with a Y specific probe for sex-mismatched transplants, complete haematological chimaerism, autologous reconstitution, or mixed chimaeric states have been defined immediately post-BMT. We have also been able to identify emerging autologous cells or relapse prior to morphological diagnosis. Forty-two children, mean age 6.4 years (range 9 months to 15 years), received an allogeneic BMT for: acute lymphoblastic leukaemia (ALL), n = 17; acute myeloid leukaemia (AML), n = 5; biphenotypic leukaemia, n = 1; myelodysplastic syndrome (MDS), n = 5; chronic granulocytic leukaemia (CGL), n = 1; severe aplastic anaemia (SAA), n = 7; familial erythrophagocytic lymphohistiocytosis (FEL), n = 2; beta thalassaemia major (beta thal), n = 1; and juvenile chronic myeloid leukaemia (JCML), n = 3. Immediately post-transplant, 78% had achieved complete haematological chimaerism, 12% had failed to engraft (DNA analysis confirmed autologous reconstitution) and 10% had mixed chimaerism. SAA was the underlying disease in two of the chimaeric cases, the third case having had a matched unrelated donor (MUD) BMT for MDS. In 3/4 cases which subsequently relapsed, DNA analysis showed re-emergence of autologous cells (indicative of relapse), prior to their morphological identification. We conclude that DNA analysis using minisatellite probes to assess graft status provides a useful contribution to patient management following allogeneic BMT.

Bone Marrow Transplantation↗

Successful allogeneic bone marrow transplantation in juvenile CML: conditioning or graft-versus-leukaemia effect?

Allogeneic BMT is the treatment of choice for juvenile CML (JCML). This has been successful following conditioning with cyclophosphamide (120 mg/kg) and total body irradiation (TBI) (10-15.75 Gy). However, busulphan (16 mg/kg) and cyclophosphamide (200 mg/kg) (Bu/Cy) conditioning has been reported to be insufficient to eradicate the malignant clone in JCML. We report successful BMT and eradication of the disease at 18 months follow-up in a child 15 months old at presentation, who was conditioned with busulphan 20 mg/kg and cyclophosphamide 200 mg/kg, with the addition of splenic irradiation. Despite using higher than conventional doses of busulphan, pharmacokinetic analysis revealed very low busulphan peak levels and rapid excretion. As a possible consequence, only partial chimerism was achieved, but full engraftment ensued following the discontinuation of cyclosporin A, rebound donor lymphocytosis and the onset of acute GVHD. We suggest that host resistance to engraftment and tumour elimination was overcome by removing a suppressive effect on donor lymphocytes, allowing a graft-versus-leukaemia effect.

Antineoplastic Combined Chemotherapy Protocols↗

Diagnosis of acute promyelocytic leukaemia by RT-PCR: detection of PML-RARA and RARA-PML fusion transcripts.

Acute promyelocytic leukaemia (APL; AML M3) is identified by a unique t(15;17) translocation which fuses the PML gene to the retinoic acid receptor alpha gene (RARA). Reverse transcription coupled with the polymerase chain reaction (RT-PCR) has been used to develop a diagnostic test for APL based on the PML-RARA fusion message. Separate PCR assays were designed to amplify either PML-RARA (15q+ derived) or RARA-PML (17q- derived) chimaeric transcripts. PML-RARA transcripts were detected in every case from a series of 18 APL patients with cytogenetically confirmed t(15;17) translocations, whereas RARA-PML messages were detected in only 67% (12/18) of these patients. This suggests that it is the 15q+ derivative which mediates leukaemogenesis. Furthermore the PCR approach (or Southern analysis) may be used to identify in which of the alternative PML introns the breakpoint occurs; 52% of cases (15/29 patients) utilize a 5' PML intron and 48% the 3' intron (14/29 cases). Neither the choice of PML intron nor the expression of the 17q- derivative could be correlated with the microgranular variant of APL (M3V), overall survival rate, age, sex or presence of coagulopathy. Finally, the fusion message is undetectable in five remission samples. This indicates a possible use for RT-PCR in monitoring remission patients for evidence of relapse.

Adolescent↗