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Biomedical subjects

M F Martelli

Publications and source records attributed to M F Martelli.

At least 37 records · Page 2Linked to original sources

Cellular therapy: exploiting NK cell alloreactivity in transplantation.

Allogeneic hematopoietic transplantation relies on T-cell alloreactions for engraftment and the graft-versus-leukemia (GVL) effect. In human leukocyte antigen (HLA) haplotype-mismatched transplants, extensive T-cell depletion of the graft is essential to prevent GVHD. This raises the question of whether mismatched transplants exert any GVL effect and whether it will ever be possible to reduce the intensity of preparative regimens. Because natural killer (NK) cells are negatively regulated by MHC class I-specific inhibitory receptors, mismatched transplants may trigger NK-cell alloreactivity. HLA class I disparities driving NK-cell alloreactions in the GVH direction mediate strong GVL effects, produce higher engraftment rates, and do not cause GVHD. In murine MHC-mismatched transplant models with no donor T-cell reactivity against the recipient, the pre-transplant infusion of donor-vs-recipient alloreactive NK cells conditioned the recipients to bone marrow transplantation without GVHD. NK-cell alloreactivity may be a unique therapeutic tool for tolerance induction and clearance of leukemia in hematopoietic transplantation.

Animals↗

Promoting ethical and objective practice in the medicolegal arena of disability evaluation.

As providers of medical information and testimony, clinicians have ultimate responsibility for ethical conduct as it relates to this information. The authors offer the following recommendations for enhancing ethical relationships between expert clinicians and the courts. 1. Avoid or resist attorney efforts at enticement into joining the attorney-client team. Such compromises of scientific boundaries and ethical principles exist on a continuum ranging from standard attorney-client advocacy at the beginning of the expert consultation phase (e.g., promotional information at the forefront of retaining an expert, with either provision of selective or incomplete records or less than enthusiastic efforts to produce all records) and extending to completion of evaluation, when requests for changes in reports and documentation might be made. 2. Respect role boundaries and do not mix conflicting roles. Remember that the treating doctor possesses a bond with the patient but does not as a rule obtain complete preinjury and postinjury information in the context of assessing causality and apportionment. In contrast, the expert witness must conduct a thorough and multifaceted case analysis sans the physician-patient relationship in order to facilitate objectivity and allow optimum diagnostic formulations. Finally, the trial consultant's function in this adversarial process is to assist with critically scrutinizing and attacking positions of experts for the opposing side. These roles all represent inherently different interests, and mixing them can only reduce objectivity. 3. Insist on adequate time for thorough record review, evaluation, and report generation. Also insist on sufficient time and preparation for deposition and court appearances. 4. Work at building a reputation for general objectivity, reliance on multiple data sources, reaching opinions only after reviewing complete information from both sides, and completing the evaluation. 5. Spend a good amount of time actually treating the patient population being examined or being offered testimony about. This treatment should be current and should be of a similar frequency to treating practitioner specialists. Be able to discuss relevant research and scientific methodology issues competently and without notes. 6. Arrive at opinions only after reviewing all of the evidence from both sides of the adversarial fence, employing multiple data sources, completing the evaluation, and interpreting data within the full context of comprehensive historical, behavioral observation, and contextual information. Being otherwise favorable to retaining attorney interests suggests endorsement of "opinion prostitute," "scientific perjurer," or "hired gun" status. The only way a practitioner can reduce the likelihood of facing an "opinion prostitute" on the opposing side in future cases is to insist on establishing and maintaining a reputation for scientific objectivity. 7. Balance cases from plaintiff and defense attorneys. Predilection for one side or the other suggests bias and sets up predisposition to nonobjectivity. For example, a preponderance of plaintiff work suggests an overdiagnosis or uncritical sympathy bias, whereas a ratio that favors hiring by the defense suggests an underdiagnosis or skepticism bias. Perhaps Brodsky's suggested cut-off ratio of .8 for favorability findings would represent an initial cutoff for defense versus plaintiff ratio. That is, experts should do at least 20% work for the opposite side of the current case being represented. Further, it might be a reasonable expectation that data on these ratios be collected as an important method for ensuring objective opinions. 8. Ensure against excessive favorability to the side of the retaining attorney or firm. Objectivity demands that scientific opinions not be influenced by the position of the legal advocate. Importantly, Brodsky recommends using a ratio of .8 as a cut-off for detecting excessive bias. That is, practitioners should possess prerequisite objectivity to disagree with the referring attorney at least 20% of the time. We suggest that a more useful cut-off would be .75, where experts are expected to generate findings that do not support the referring attorney's position at least 25% of the time. 9. Never arrive at opinions that are inconsistent with plaintiff records, examination data, test data, behavioral presentation, and so forth, especially when such opinions are favorable to the side of the retaining attorney firm. Instead, use the following recommendations. (ABSTRACT TRUNCATED)

Disability Evaluation↗

Does pain confound interpretation of neuropsychological test results?

There is increasing evidence that pain and related problems (e.g., affective distress, sleep disturbance, medication use) can interfere with cognitive performance and confound the interpretation of neuropsychological test results. This may be of particular concern in cases of the persistent post-concussive syndrome where headache is the primary problem. Such effects can be pronounced, obscuring the effects associated with mild or even much more significant brain injury. However, it remains unclear what specific chronic or acute pain experiences, in what individuals, with or without which associated problems, will actually result in particular performance deficits. Whereas pain may disrupt brain function, this is likely to be temporary and not indicative of permanent impairment of neuropsychological function. Further study of this important topic is warranted.

Data Interpretation, Statistical↗

Limited engraftment capacity of bone marrow-derived mesenchymal cells following T-cell-depleted hematopoietic stem cell transplantation.

The engraftment capacity of bone marrow-derived mesenchymal cells was investigated in 41 patients who had received a sex-mismatched, T-cell-depleted allograft from human leukocyte antigen (HLA)-matched or -mismatched family donors. Polymerase chain reaction (PCR) analysis of the human androgen receptor (HUMARA) or the amelogenin genes was used to detect donor-derived mesenchymal cells. Only 14 marrow samples (34%) from 41 consenting patients generated a marrow stromal layer adequate for PCR analysis. Monocyte-macrophage contamination of marrow stromal layers was reduced below the levels of sensitivity of HUMARA and amelogenin assays (5% and 3%, respectively) by repeated trypsinizations and treatment with the leucyl-leucine (leu-leu) methyl ester. Patients who received allografts from 12 female donors were analyzed by means of the HUMARA assay, and in 5 of 12 cases a partial female origin of stromal cells was demonstrated. Two patients who received allografts from male donors were analyzed by amplifying the amelogenin gene, and in both cases a partial male origin of stromal cells was shown. Fluorescent in situ hybridization analysis using a Y probe confirmed the results of PCR analysis and demonstrated in 2 cases the existence of a mixed chimerism at the stromal cell level. There was no statistical difference detected between the dose of fibroblast progenitors (colony-forming unit-F [CFU-F]) infused to patients with donor- or host-derived stromal cells (1.18 +/- 0.13 x 10(4)/kg vs 1. 19 +/- 0.19 x 10(4)/kg; P >/=.97). In conclusion, marrow stromal progenitors reinfused in patients receiving a T-cell-depleted allograft have a limited capacity of reconstituting marrow mesenchymal cells.

Adult↗

Interphase FISH for Y chromosome, VNTR polymorphisms, and RT-PCR for BCR-ABL in the monitoring of HLA-matched and mismatched transplants.

Thirty-six sex-mismatched transplants were studied using fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) methods. Molecular cytogenetics was performed using interphase FISH with a centromeric probe for chromosome Y, and PCR amplification was performed with a set of VNTR microsatellite loci. In addition, reverse transcriptase-PCR (RT-PCR) for BCR-ABL fusion was used to investigate cases of Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL). Our integrated approach of post-transplant monitoring was helpful in documenting successful transplants and in controlling the size of Ph-positive clones in CML. A striking overlap was found between results from FISH analysis and PCR for polymorphic loci.

Adolescent↗

Microdissection and FISH investigations in acute myeloid leukemia: a step forward to full identification of complex karyotypic changes.

Complex chromosomal rearrangements in malignant hemopathies frequently remain unclarified because of paucity of material for further fluorescence in situ hybridization analyses and/or lack of suitable probes. Chromosome microdissection (MD) can be an adequate approach to elucidate chromosome aberrations unrecognizable by conventional karyotyping. We applied MD in two patients with acute myeloid leukemia (AML) and unidentified chromosome changes at karyotype. Microdissection of a ring chromosome in an AML-M5 case revealed 21q polysomy. In an AML-M4 case, MD of an add(15p) disclosed a t(8;15) with over-representation of both 8q22 and 8q24 bands. YAC probes were helpful in showing duplication of the ETO gene at 8q22, and amplification of C-MYC, at 8q24.

Aneuploidy↗

Transplantation tolerance induced by "mega dose" CD34+ cell transplants.

Early studies in murine models and more recent clinical data in heavily pretreated leukemia patients have shown that escalation of hematopoietic progenitor cells can overcome major genetic barriers and enable rapid and durable engraftment of haploidentical 3-loci mismatched transplants without graft-versus-host disease. In vitro studies suggest that veto cells within the progenitors population most likely mediate this facilitating effect. Leukemia relapse is relatively low in patients with acute myeloid leukemia (AML) but is greater in adults with acute lymphoblastic leukemia (ALL). Donor NK cells most likely mediate the resistance to relapse in patients with AML who are recipients of haploidentical transplants. Immune reconstitution in adults but not in children is slow as in adult recipients of HLA matched unrelated bone marrow transplants. The "mega dose" concept was also shown recently to be useful for tolerance induction in sublethally irradiated mice, so as to effectively overcome the marked resistance presented by the large number of lymphocytes surviving the sublethal conditioning. Thus, allogeneic chimeras generated by transplantation of large doses of Sca1+Lin- cells, permanently accept allogeneic donor type skin grafts. However, the numbers required to attain this desirable goal may not be easily collected from human donors. Nonalloreactive T cells synergize with murine Sca1+Lin- cells and might, therefore, enable achievement of engraftment of haploidentical transplants in sublethally conditioned patients.

Adult↗

Tolerance induction by 'megadose' transplants of CD34+ stem cells: a new option for leukemia patients without an HLA-matched donor.

Early studies in murine models and more recent clinical data in heavily pre-treated leukemia patients have shown that escalation of the dose of hematopoietic progenitor cells can overcome major genetic barriers and enable rapid and durable engraftment of haploidentical, three-locus-mismatched transplants without graft-versus-host disease. In vitro studies suggest that veto cells within the progenitor population most probably mediate this facilitating effect.

Animals↗

Chronic pain and neuropsychological functioning.

This review article examines the effect of chronic pain on neuropsychological functioning. Primary attention is given to studies that include patient groups without a history of traumatic brain injury (TBI) or neurologic disorders. Numerous studies were identified that demonstrate neuropsychological impairment in patients with chronic pain, particularly on measures assessing attentional capacity, processing speed, and psychomotor speed. Despite suggestive findings, further studies are needed to clarify the variables that mediate the impact of pain on neuropsychological functioning and the unique role of various symptoms often associated with chronic pain.

Attention↗

T-lymphocyte function after retroviral-mediated thymidine kinase gene transfer and G418 selection.

Generation of an efficient graft-versus-leukemia (GVL) effect in patients with hematological malignancies who relapse after allogeneic bone marrow transplantation depends in part upon the number of infused T lymphocytes. Currently, a GVL reaction cannot be achieved without inducing concomitant graft-versus-host disease (GVHD); thus, one strategy is to try to modulate this GVL/GVHD ratio. We engineered human T lymphocytes with herpes simplex virus-thymidine kinase and neomycin resistance genes, with an LXSN-derived vector that confers a ganciclovir-specific sensitivity to the transduced T cells. We analyzed proliferation, interleukin-2 production, alloreactivity in a mixed lymphocyte culture, and clonogenicity during the different stages of retroviral infection and G418 selection. Our results confirm that a sufficient number of transduced T lymphocytes can be obtained after selection for clinical studies. Their proliferative activity, alloresponsiveness, and ability to produce and respond to interleukin-2 were retained. Compared with control populations, their clonogenicity, as assessed by limiting dilution assays, was reduced after retroviral infection and G418 selection by 1.6 and 2.9 logs, respectively, with both viral supernatant incubation and coculture procedures. This study shows that infection and selection with the thymidine kinase-neomycin resistance gene retroviral vector significantly reduces the number of functional T lymphocytes. This finding should be taken into account when establishing the dose of T lymphocytes necessary to trigger a modulated GVL/GVHD effect.

Anti-Bacterial Agents↗

In vivo demethylation of a MoMuLV retroviral vector expressing the herpes simplex thymidine kinase suicide gene by 5' azacytidine.

We constructed a functional MoMuLV-based bicistronic retroviral vector encoding the herpes simplex virus type I thymidine kinase gene, which induces sensitivity to the prodrug ganciclovir (gcv), and the reporter beta-galactosidase gene (MFG-tk-IRES-lacZ). The U937 histiocytic cell line was transduced with this vector, and a clone (VB71) with high-level transgene expression was selected. Severe combined immunodeficient (SCID) mice were injected with VB71 cells to evaluate the role of long terminal repeat methylation in transgene silencing in vivo and to see whether 5-azacytidine (5' aza-C) demethylating agent prevented it. We found 5' aza-C maintained gene expression at high level in vitro. In vivo, time to tumor onset was significantly longer in SCID mice receiving the VB71 cells, 5' aza-C, and gcv compared with animals treated with either 5' aza-C or gcv alone. The number of injected tumor cells influences tumor onset time and the efficacy of 5' aza-C and gcv treatment. The standard gcv treatment schedule (10 mg/kg from d + 1 until the onset of tumor) controlled tumor onset better than short-term treatment with high doses. In conclusion, the results extend our previous findings that transgene methylation in vivo may be prevented with an appropriate schedule of 5' aza-C and gcv.

Animals↗

Cytogenetic characterization of acute myeloid leukemia in Shwachman's syndrome. A case report.

We report on a case of acute myeloid leukemia in a 17-year old boy affected by Shwachman Diamond syndrome (SDS). Conventional cytogenetics at diagnosis revealed an abnormal clone with complex karyotypic changes including typical myeloid aberrations, such as monosomy 5, tetrasomy of chromosome 8, trisomy 9, and deletion of the short arm of chromosome 12. The boy was treated with conventional chemotherapy and reached complete remission of leukemia, confirmed by cytogenetics and fluorescence in situ hybridization. Nevertheless he failed to regenerate normal marrow cellularity and blood cell count. Cytogenetic information on hematologic malignancies in SDS patients are discussed.

Abnormalities, Multiple↗

Role of natural killer cell alloreactivity in HLA-mismatched hematopoietic stem cell transplantation.

Because of the expression of inhibitory receptors (KIR) for major histocompatibility complex (MHC) class I allotypes, a person's natural killer (NK) cells will not recognize and will, therefore, kill cells from individuals lacking his/her KIR epitopes. This study investigated the role of NK cell alloreactivity in human HLA haplotype-mismatched hematopoietic stem cell transplantation and, specifically, the role of the three major NK specificities, ie, those for HLA-C group 1, HLA-C group 2, and HLA-Bw4 alleles. In 20 of 60 donor-recipient pairs, KIR epitope incompatibility and functional analyses of donor NK cell clones predicted donor NK cells could cause graft-versus-host (GVH)/graft-versus-leukemia (GVL) reactions. NK cell clones of donor origin were obtained from transplanted recipients and tested for lysis of recipient's cryopreserved pretransplant lymphocytes. Despite the absence of GVH disease, we detected high frequencies of NK clones which killed recipient's target cells. Lysis followed the rules of NK cell alloreactivity, being blocked only by the MHC class I KIR epitope which was missing in the recipient. The alloreactive NK clones also killed the allogeneic leukemia. Transplants from these KIR epitope incompatible donors had higher engraftment rates. Therefore, a GVL effector and engraftment facilitating mechanism, which is independent of T-cell-mediated GVH reactions, may be operational in HLA mismatched hematopoietic cell transplants.

Adolescent↗

The role of megadose CD34+ progenitor cells in the treatment of leukemia patients without a matched donor and in tolerance induction for organ transplantation.

Throughout the 1980s, transplantation of unmodified (T cell-replete) bone marrow from full haplotype incompatible family donors was associated with an unsuccessful outcome because of graft failure and severe graft-versus-host disease (GVHD), at times affecting up to 90% of recipients. Although extensive T cell depletion of donor bone marrow was successful in preventing GVHD in children with severe combined immunodeficiency disease (SCID), results were disappointing in leukemic patients because the benefit of preventing GVHD was offset by graft failure. Resistance to engraftment appears to be mediated by host-derived cytotoxic T-lymphocyte precursors that survive supralethal conditioning. In the present paper, we review data that show that these genetic histocompatibility barriers can be overcome in stringent mouse models, employing lethally as well as sublethally irradiated recipients, by two major approaches that are synergistic to each other: escalation of hematopoietic progenitor cell dose and the use of nonalloreactive T cells. The former approach is already being successfully implemented in the treatment of leukemic patients.

Animals↗

ALK+ lymphoma: clinico-pathological findings and outcome.

A distinct pathologic entity (ALK+ lymphoma) that is characterized by expression of the anaplastic lymphoma kinase (ALK) protein has recently emerged within the heterogeneous group of CD30(+) anaplastic large-cell lymphomas. Information on clinical findings and treatment outcome of ALK+ lymphoma is still limited, and no data are available concerning the value of the International Prognostic Index when applied to this homogeneous disease entity. To clarify these issues, a recently developed monoclonal antibody ALKc (directed against the cytoplasmic portion of ALK) was used to detect expression of the ALK protein in paraffin-embedded biopsies from 96 primary, systemic T/null anaplastic large-cell lymphomas, and the ALK staining pattern was correlated with morphological features, clinical findings, risk factors (as defined by the International Prognostic Index), and outcome in 78 patients (53 ALK+ and 25 ALK-). Strong cytoplasmic and/or nuclear ALK positivity was detected in 58 of 96 ALCL cases (60.4%), and it was associated with a morphological spectrum (common type, 82.7%; giant cell, 3.5%; lymphohistiocytic, 8. 6%; and small cell, 5.2%) that reflected the ratio of large anaplastic elements (usually showing cytoplasmic and nuclear ALK positivity) to small neoplastic cells (usually characterized by nucleus-restricted ALK expression). Clinically, ALK+ lymphoma mostly occurred in children and young adults (mean age, 22.01 +/- 10.87 years) with a male predominance (male/female [M/F] ratio, 3.0) that was particularly striking in the second-third decades of life (M/F ratio, 6.5) and usually presented as an aggressive, stage III-IV disease, frequently associated with systemic symptoms (75%) and extranodal involvement (60%), especially skin (21%), bone (17%), and soft tissues (17%). As compared with ALK+ lymphoma, ALK- cases occurred in older individuals (mean age, 43.33 +/- 16.15 years) and showed a lower M/F ratio (0.9) as well as lower incidence of stage III-IV disease and extranodal involvement at presentation. Overall survival of ALK+ lymphoma was far better than that of ALK- anaplastic large-cell lymphoma (71% +/- 6% v 15% +/- 11%, respectively). However, within the good prognostic category of ALK+ lymphoma, survival was 94% +/- 5% for the low/low intermediate risk group (age-adjusted International Prognostic Index, 0 to 1) and 41% +/- 12% for the high/high intermediate risk group (age-adjusted International Prognostic Index, >/=2). Multivariate analysis identified ALK expression and the International Prognostic Index as independent variables that were able to predict survival among T/null primary, systemic anaplastic large-cell lymphoma. Thus, we suggest that such parameters should be taken into consideration for the design of future clinical trials.

Adult↗

Identification of multiple copies of a 20q-chromosome in a case of myelodysplastic syndrome: a FISH study.

In myelodysplastic syndromes (MDS) karyotypic aberrations identify subgroups of patients with distinct clinical-morphological features and can be relevant in risk assessment of developing leukemia. Often conventional cytogenetic analysis is not sufficiently informative due to the presence of partially or completely unrecognizable chromosome markers. By chromosome microdissection (MD) and fluorescence in situ hybridization (FISH) we investigated the nature of a karyotypic marker occurring in multiple copies in one case of MDS arisen in a patient previously treated for breast cancer. Results showed dicentrics derived from telomeric fusion between interstitially deleted 20q-chromosomes. The abnormal karyotype resulted into polysomy for a deleted chromosome 20q.

Aged↗

Stem cell escalation enables HLA-disparate haematopoietic transplants in leukaemia patients.

Resistance to engraftment of bone marrow transplants appears to be mediated by host-derived cytotoxic T-cell precursors that survive supralethal conditioning. Here, Yair Reisner and Massimo Martelli review engraftment studies showing that escalation of haematopoietic progenitor cell dose induces transplantation tolerance, thereby overcoming major genetic histocompatibility barriers.

Animals↗