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Biomedical subjects

M M Wolf

Publications and source records attributed to M M Wolf.

At least 19 recordsLinked to original sources
PubMed2005

Sequential generation of entangled multiqubit states.

We consider the deterministic generation of entangled multiqubit states by the sequential coupling of an ancillary system to initially uncorrelated qubits. We characterize all achievable states in terms of classes of matrix-product states and give a recipe for the generation on demand of any multiqubit state. The proposed methods are suitable for any sequential generation scheme, though we focus on streams of single-photon time-bin qubits emitted by an atom coupled to an optical cavity. We show, in particular, how to generate familiar quantum information states such as W, Greenberger-Horne-Zeilinger, and cluster states within such a framework.

Journal Article↗
PubMed2005

Non-Gaussian cloning of quantum coherent states is optimal.

We consider the optimal cloning of quantum coherent states with single-clone and joint fidelity as figures of merit. While the latter is maximized by a Gaussian cloner, the former is not: the optimal single-clone fidelity for a symmetric 1-to-2 cloner is 0.6826, compared to 2/3 in a Gaussian setting. This cloner can be realized with an optical parametric amplifier and certain non-Gaussian bimodal states. Finally, we show that the single-clone fidelity of the optimal 1-to-infinity cloner is 1/2. It is achieved by a Gaussian scheme and cannot be surpassed even with supplemental bound entangled states.

Journal Article↗
PubMed2005

Quantum benchmark for storage and transmission of coherent states.

We consider the storage and transmission of a Gaussian distributed set of coherent states of continuous variable systems. We prove a limit on the average fidelity achievable when the states are transmitted or stored by a classical channel, i.e., a measure and repreparation scheme which sends or stores classical information only. The obtained bound is tight and serves as a benchmark which has to be surpassed by quantum channels in order to outperform any classical strategy. The success in experimental demonstrations of quantum memories as well as quantum teleportation has to be judged on this footing.

Journal Article↗
PubMed2005

Renormalization-group transformations on quantum states.

We construct a general renormalization-group transformation on quantum states, independent of any Hamiltonian dynamics of the system. We illustrate this procedure for translational invariant matrix product states in one dimension and show that product, Greenberger-Horne-Zeilinger, W, and domain wall states are special cases of an emerging classification of the fixed points of this coarse-graining transformation.

Journal Article↗
PubMed2005

Cardiovascular toxicity is increased, but manageable, during high-dose chemotherapy and autologous peripheral blood stem cell transplantation for patients aged 60 years and older.

High-dose therapy (HDT) for non-Hodgkins lymphoma (NHL) and multiple myeloma (MM) is considered a feasible option for patients aged 60 years. This study compared the outcomes for all patients aged 60 years treated with HDT at the center to a matched cohort group aged <60 years. Results for patients who were 60 years at HDT between 1997--2002 were retrospectively analysed to assess efficacy and safety. Event-free (EFS) and overall survival (OS) rates were compared with a cohort group, matched by disease type, chemotherapy sensitivity, year of treatment and conditioning regimen. Patients with NHL were also matched by International Prognostic Index score. Forty patients aged 60 years were identified. Median age was 65 (range 60--76) with 22 MM and 18 NHL; 50% had 1 or more co-morbidity; 35% had cardiovascular co-morbidity vs. 18% of controls (p=0.075). Response rates (RR) following HDT for MM were: 4 (18%) complete responses (CR) and 18 (82%) partial responses (PR), giving an overall response rate (ORR) of 100%, vs. 77% for controls (p=0.02). For NHL patients there were: 8 CR (44%) and 4 PR (22%), giving an ORR of 67%, vs. 83% for controls (p=0.3). Transplant-related mortality was 8% compared to 5% in controls (p=0.6). Toxicities were similar with the exception of cardiac toxicity, which was significantly higher in patients aged 60 years vs. controls (50% grade 3 vs. 10%: p<0.0001). Atrial fibrillation was the most frequent cardiovascular toxicity (9 patients). At a median follow-up of 33 months, there is no significant difference between older vs. younger patients in median EFS (24 vs. 38 months: p=0.78) or OS (40 months vs. not reached: p=0.23). HDT is feasible and effective in selected patients 60 years with MM and NHL. Patients 60 years are more susceptible to cardiovascular toxicities, particularly atrial fibrillation, but have similar or better response rates following HDT and similar long-term outcomes to younger patients.

Adult↗
PubMed2004

Entanglement frustration for Gaussian states on symmetric graphs.

We investigate the entanglement properties of multimode Gaussian states, which have some symmetry with respect to the ordering of the modes. We show how the symmetry constrains the entanglement between two modes of the system. In particular, we determine the maximal entanglement of formation that can be achieved in symmetric graphs like chains, 2D and 3D lattices, mean field models and the platonic solids. The maximal entanglement is always attained for the ground state of a particular quadratic Hamiltonian. The latter thus yields the maximal entanglement among all quadratic Hamiltonians having the considered symmetry.

Journal Article↗
PubMed2003

Entanglement of formation for symmetric Gaussian states.

We show that for a fixed amount of entanglement, two-mode squeezed states are those that maximize Einstein-Podolsky-Rosen-like correlations. We use this fact to determine the entanglement of formation for all symmetric Gaussian states corresponding to two modes. This is the first instance in which this measure has been determined for genuine continuous variable systems.

Journal Article↗
PubMed2003

Optimum trephine length in the assessment of bone marrow involvement in patients with diffuse large cell lymphoma.

BACKGROUND: The National Cancer Institute has recommended a bone marrow biopsy length of >/=20 mm for the staging and surveillance of patients with non-Hodgkin's lymphoma. However, there are few published data to support this recommendation, particularly the role of examining multiple levels. PATIENTS AND METHODS: Bone marrow biopsies from 172 patients with newly diagnosed diffuse large cell lymphoma (DLCL) entered in two consecutive trials of the Australasian Leukaemia and Lymphoma Group were analysed. The original haematoxylin and eosin-stained trephine biopsy and two or more deeper sections cut at 0.1-0.2 mm intervals were assessed with respect to the morphology, extent and pattern of lymphomatous involvement. The rate of positive diagnosis was correlated with the length of the biopsy specimen and the number of sections examined. RESULTS: Forty-seven biopsies (27%) demonstrated marrow involvement on examination of a mean of four trephine biopsy sections. The rate of positivity increased with the examination of multiple levels and correlated with increasing trephine length but was not dependent on the number of sites sampled. Twenty per cent of biopsies <20 mm in length were positive for lymphoma; this increased to 35% for biopsies >/=20 mm (P = 0.023). CONCLUSIONS: Morphological bone marrow involvement in DLCL is optimally demonstrated by a 20-mm long trephine biopsy from a single site which is examined at multiple levels (four or more). This obviates the need for bilateral sampling, thereby reducing patient morbidity from the procedure. This study provides evidence to support the National Cancer Institute recommendations regarding trephine biopsy in the staging of DLCL, providing multiple levels are examined.

Biopsy↗
PubMed2002

Intrathecal chemotherapy alone is inadequate central nervous system prophylaxis in patients with intermediate-grade non-Hodgkin's lymphoma.

Central nervous system (CNS) relapse of non-Hodgkin's lymphoma (NHL) is usually fatal despite therapy and effective prophylaxis is desirable. Patients at high-risk usually receive intrathecal (i.t.) prophylaxis, although its efficacy is unproven. We therefore analyzed the outcome of all patients with newly diagnosed "intermediate-grade" NHL receiving i.t. prophylaxis from 1991 to 1999. Twenty-six patients were identified and analyzed. All were free of CNS involvement at diagnosis with negative cerebrospinal fluid (CSF) cytology. Disease stage was IE in 7, and IV in 19, with a median of two extranodal sites involved. Serum lactate dehydrogenase was elevated in 65%, and the median International Prognostic Factors Index score was 3 (range 0-5). Anthracycline-based chemotherapy was used in all cases and included high-dose methotrexate +/- ara-C in six patients. The median number of i.t. treatments was 5 (range 1-12) and comprised methotrexate +/- steroid in 15, together with ara-C in 11. The actuarial 3-year CNS-relapse rate was 26 +/- 10%. Six CNS-relapses were observed and involved the spinal cord or brain parenchyma in two cases each, and the leptomeninges in four patients. Treatment-related variables associated with higher CNS-relapse rates (34-50%) were: delay of > or = 14 days from diagnosis to first i.t. injection, < 5 i.t. treatments, delay of i.t. prophylaxis until after attaining CR and systemic treatment lacking high-dose methotrexate +/- ara-C (each P < or = 0.17). I.t. CNS prophylaxis, as used here, was inadequate. Alternative approaches should be pursued.

Adolescent↗
PubMed2001

Distillability via protocols respecting the positivity of partial transpose.

We show that all quantum states that do not have a positive partial transpose are distillable via channels, which preserve the positivity of the partial transpose. The question whether bound entangled states with non-positive partial transpose exist is therefore closely related to the connection between the set of separable superoperators and positive partial transpose-preserving maps.

Journal Article↗
PubMed2001

Bound entangled Gaussian states.

We discuss the entanglement properties of bipartite states with Gaussian Wigner functions. For the separability, and the positivity of the partial transpose, we establish explicit necessary and sufficient criteria in terms of the covariance matrix of the state. It is shown that, for systems composed of a single oscillator for Alice and an arbitrary number for Bob, positivity of the partial transpose implies separability. However, this implication fails with two oscillators on each side, as we show by constructing a five parameter family of bound entangled Gaussian states.

Journal Article↗
PubMed2001

Primary large-cell non-Hodgkin's lymphoma of the testis: a retrospective analysis of patterns of failure and prognostic factors.

We have analyzed 25 patients with primary testicular large-cell non-Hodgkin's lymphoma managed at our institution from 1972-1998. The median age was 69 years, with bilateral testicular involvement in 16%. The disease stage was I in 56%, II in 32%, and IV in 12%. Twenty-four patients received further therapy after orchiectomy, including chemotherapy in 18 and radiation therapy in 11 (encompassing regional nodes in 8 and the contralateral testis in 6), with 5 patients receiving both modalities. The complete remission rate was 88%, but a continuous pattern of recurrence is evident up to 10 years, when only 23% of patients are predicted to be in ongoing remission. The dominant sites of first failure were extranodal (91%), with prominent involvement of the contralateral testis and cerebral parenchyma. The 10-year overall survival rate is 32%, and the median overall survival is 4.4 years. Within the entire cohort, adverse prognostic factors for treatment failure were serum albumin < or = to 3.5 g/dL (P = 0.02), advanced age, advanced stage, and lack of anthracycline-containing chemotherapy (each P < or = to 0.3). Among patients with locoregional disease, albumin < or = to 3.5 g/dL (P = 0.08), no anthracycline-containing chemotherapy (P = 0.15), and fewer than 6 cycles of chemotherapy (P = 0.03) remained predictive. Based on this analysis, we are prospectively evaluating a treatment program for patients with testicular non-Hodgkin's large-cell lymphoma comprising (1) 6 cycles of anthracycline-based chemotherapy, (2) prophylactic radiation therapy to the contralateral testis, and (3) central nervous system prophylaxis with both intrathecal chemotherapy and systemic high-dose methotrexate.

Age Factors↗
PubMed1999

A phase I/II study of intensive dose escalation of cytarabine in combination with idarubicin and etoposide in induction and consolidation treatment of adult acute myeloid leukemia. Australian Leukaemia Study Group (ALSG).

To determine the safety and efficacy of the combination of idarubicin, cytarabine and etoposide ("ICE") for induction and consolidation treatment of acute myeloid leukemia (AML), and of dose-intensification of cytarabine in this setting, 54 previously untreated patients in three cohorts were studied by sequential dose escalation of cytarabine, in combination with standard doses of idarubicin and etoposide. Cytarabine was given to Cohort 1 at the conventional dosage of 100 mg/m2 per day by continuous infusion for 7 days in induction and 5 days in consolidation; to Cohort 2 at high-dose (HiDAC) (3 g/m2 intravenously twice daily on days 1, 3, 5 and 7) during induction with conventional dosage during consolidation; to Cohort 3 HiDAC was given for both induction and consolidation. In addition, Cohort 3 patients received lenograstim (Granocyte; rHuG-CSF) after both induction and consolidation courses. We found that there was no significant difference between the three cohorts in hematological toxicity in induction, but that HiDAC was associated with a greater incidence of gastro-intestinal toxicities. There was no difference in induction mortality between the three cohorts, which was 11% overall. Consolidation with HiDAC led to a significant increase in hematological toxicity. Overall, the complete remission (CR) rate was 80% with no significant difference between the three regimens. The estimated disease free survival at 3 years was 28%, 67% and 54% respectively for Cohorts 1, 2 and 3 with an estimated overall survival of 38%, 63% and 47%. We conclude that cytarabine dosage can be escalated safely in combination with idarubicin and etoposide in both induction and consolidation. The combination is effective for induction treatment of AML and its side-effects appear similar to those of standard regimens. Whether its use offers long-term benefits compared with standard regimens is the subject of ongoing controlled randomized studies.

Adolescent↗
PubMed1996

A randomized study of high-dose cytarabine in induction in acute myeloid leukemia.

High-dose cytarabine (ara-c) may overcome cytarabine resistance in leukemic blasts. It has been used as a successful salvage and in postremission therapy but not as initial induction treatment. Patients aged 15 to 60 years, presenting with newly diagnosed acute myeloid leukemia (AML) were randomized to receive either high-dose cytarabine, 3 g/m2 12 hourly on days 1, 3, 5, and 7 for 8 doses, daunorubicin 50 mg/m2 days 1 to 3, etoposide 75 mg/m2 days 1 to 7, (HIDAC-3-7) or standard dose cytarabine 100 mg/m2 continuous intravenous infusion for 7 days with daunorubicin and etoposide at the same dose and schedule as above (7-3-7). Patients could receive a second or third induction course if complete remission (CR) was not achieved. All patients received the same postinduction consolidation therapy (5-2-5) for 2 courses. Eligible patients had no prior chemotherapy or myelodysplastic disease. Patients have been followed for a median of 4.5 years. Of 301 patients treated, complete response (CR) was achieved in 71% with HIDAC-3-7 and 74% with 7-3-7. For patients in CR, the estimated median remission duration was 45 months with HIDAC-3-7 and 12 months with 7-3-7 (P = .0005 univariate analysis, P = .0004 multivariate analysis). The estimated percentage of patients relapse free 5 years after achieving a CR was 49% on HIDAC-3-7 and 24% on 7-3-7. Patients in CR tended to survive longer with HIDAC-3-7 but there were no overall survival differences between the two arms. HIDAC-3-7 was associated with significantly more toxicity in induction with more leukopenia, thrombocytopenia, nausea, and vomiting and eye toxicity (all P < .001) but a similar incidence of severe central nervous system and cerebellar toxicity compared to 7-3-7. The consolidation treatment was the same in both arms but caused significantly more leukopenia and thrombocytopenia in patients previously treated with HIDAC-3-7 induction (P < .0001). We conclude that a dose-effect exists for cytarabine in AML and that HIDAC-3-7 prolongs remission duration and disease-free survival and is tolerable when used as initial induction therapy in patients with de novo AML.

Acute Disease↗
PubMed1995

Comparison of the sensitivity of the caudal fold skin test and a commercial gamma-interferon assay for diagnosis of bovine tuberculosis.

A study to determine and compare the sensitivity of the caudal fold tuberculin test (CFT) and a commercial gamma-interferon (gamma-IFN) assay for diagnosis of bovine tuberculosis was conducted. A dairy herd with approximately a third of the cattle infected with Mycobacterium bovis was chosen for this study. All cattle from this herd were slaughtered, and tissue specimens for bacteriologic culturing and histologic examination were collected. Results of the CFT and gamma-IFN assay were compared with results of bacteriologic culturing and histologic examination to determine test sensitivity. Results were analyzed, using each of the following 4 standards to classify cattle as infected: positive test result by bacteriologic culturing only; histologic examination only; bacteriologic culturing and histologic examination; and bacteriologic culturing or histologic examination. Sensitivity of the CFT ranged from 80.4 to 84.4%, depending on the standard of comparison. Sensitivity of the gamma-IFN assay ranged from 55.4 to 97.1%, depending on the standard of comparison and on the method of interpretation. The CFT was significantly (P < 0.001) more sensitive than the gamma-IFN assay for diagnosis of bovine tuberculosis when the gamma-IFN assay was conducted and interpreted as instructed by the manufacturer. Maximum overall sensitivity was achieved when results of the CFT and gamma-IFN assay were interpreted in parallel.

Animals↗
PubMed1994

Randomized comparison of MACOP-B with CHOP in patients with intermediate-grade non-Hodgkin's lymphoma. The Australian and New Zealand Lymphoma Group.

PURPOSE: To compare complete response rates, time to failure, survival, and toxicity for patients with intermediate-grade non-Hodgkin's lymphoma (NHL) treated with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) versus those treated with a regimen consisting of methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisolone, and bleomycin (MACOP-B), in a multicenter, randomized controlled trial performed by 22 centers of the Australian and New Zealand Lymphoma Group (ANZLG). PATIENTS AND METHODS: Between October 1986 and June 1991, 304 patients were randomized, of whom 236 were eligible for analysis. Eligibility criteria included diffuse small cleaved-cell, diffuse mixed small- and large-cell, follicular large-cell, diffuse large-cell, and large-cell immunoblastic, stages I bulky or II to IV. RESULTS: There was no significant difference in complete response rates (51% for MACOP-B v 59% for CHOP), failure-free survival, or overall survival in the two treatment arms. The rate of death of MACOP-B patients relative to CHOP patients was estimated to be 0.91 (P = .64) when stratified by prognostic group. There were no significant differences between the two regimens in any of the prognostic subgroups. Toxicity was significantly more severe with MACOP-B, particularly cutaneous toxicity, stomatitis, and gastrointestinal ulceration. The average relative dose-intensity (RDI) of MACOP-B was 0.91 and of CHOP was 0.90, indicating good dose delivery in this multicenter group setting. CONCLUSION: CHOP chemotherapy produced results equivalent to those of MACOP-B in patients with intermediate-grade NHL and with significantly fewer toxic complications. Despite relatively poor results in some patient subgroups, CHOP remains the standard chemotherapy for this disease, against which all new regimens should be compared.

Adolescent↗
PubMed1992

A randomised trial of dexamethasone, lorazepam and prochlorperazine for emesis in patients receiving chemotherapy.

To define further the place of dexamethasone in antiemetic combinations, lorazepam, prochlorperazine and placebo (LP) were compared with lorazepam, prochlorperazine and dexamethasone (DLP) in a randomised, double-blind, crossover study. Both patient and observer assessments were documented in 84 patients receiving both cisplatin and non-cisplatin chemotherapy. The addition of dexamethasone significantly reduced the severity of nausea (P = 0.002) and vomiting (P less than 0.0001), duration of nausea (P = 0.01) and vomiting (P = 0.002) and the number of vomiting episodes (P = 0.003). DLP was the superior regimen in subsets of patients receiving cisplatin and the non-cisplatin chemotherapy. The improvements produced by the dexamethasone regimen were large and of major benefit to our patients. Patients documented significantly improved tolerance to chemotherapy with DLP courses (P = 0.0006). Overall, significantly more patients preferred DLP (P less than 0.0001). Patient assessments produced results similar to observer assessments but gave a broader understanding of their experience. The addition of dexamethasone to prochlorperazine and lorazepam significantly improved our patients' experience while receiving chemotherapy.

Adult↗