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Biomedical subjects

M Keating

Publications and source records attributed to M Keating.

At least 91 records · Page 5Linked to original sources
PubMed1997

Association between increased body mass index and a diagnosis of acute promyelocytic leukemia in patients with acute myeloid leukemia.

We had observed that several patients with acute promyelocytic leukemia (APL) were markedly obese. Therefore we determined the relationship between obesity and a diagnosis of APL among patients with acute myelocytic leukemia (AML). Between 1980 and 1995 we saw 1245 patients with newly-diagnosed AML of whom 120 had APL. Increasing body mass index (BMI) was strongly associated with a diagnosis of APL (P=0.0003). Like Douer et al (Blood 1996; 8: 303-313) we found APL to be more frequent in Latinos and younger patients (P < 10[-4] for both). Logistic regression indicated that increasing BMI, decreasing age, and Latino origin were each independently associated with a diagnosis of APL (multivariate P values <10[-4], <10[-4], 0.0035, respectively). Since the mean BMI in the non-APL patients (25.1) resembled that of the general US population, it appears that APL patients are 'heavy' and not that non-APL patients are 'thin'. Five of the APL patients (4.2%) had a BMI >50 (vs none of the other 1125 AML patients). Given the distribution of BMI in the general US population ages 17-74, the probability that five of 120 normal adults would have a BMI >50 is virtually nil. Excluding the five very heavy APL patients does not alter the conclusion that increasing BMI predicted for APL in patients with AML. Although the mechanism is unclear there appears to be an association between increasing BMI and a diagnosis of APL among patients with AML. There may also be an association between APL and obesity.

Acute Disease↗
PubMed1997

Results of decitabine therapy in the accelerated and blastic phases of chronic myelogenous leukemia.

The aim of the study was to evaluate the activity of decitabine, a hypomethylating agent, in the treatment of patients with chronic myelogenous leukemia (CML) in transformation. Thirty-seven patients with CML in blastic (20 patients) or accelerated phases (17 patients) were treated. Their median age was 52 years; 36 had Philadelphia chromosome-positive disease. Decitabine was given at 100 mg/m2 over 6 h every 12 h x 10 doses (1000 mg/m2) to 13 patients, and at 75 mg/m2 over 6 h every 12 h x 10 doses (750 mg/m2) to 24 patients. In blastic phase, two patients (10%) achieved a complete hematologic response (one with Ph suppression), and three (15%) had a hematologic improvement (marrow CR, platelets <100 x 10[3]/microl), for an overall response rate of 25%. In accelerated phase, six patients (35%) returned to a second chronic phase (two with Ph suppression), one (6%) had a hematologic improvement, and two (12%) had a partial hematologic response, for an overall response rate of 53%. Prolonged myelosuppression was the most significant side-effect. The median time to recovery of granulocytes above 500/microl was 48 days, and to recovery of platelets above 30 x 10(3)/microl, 31 days. Febrile episodes occurred in 25 patients (68%) including documented infections in 17 patients (46%). Decitabine has promising activity in CML. The most significant side-effect is prolonged myelosuppression. Decitabine may show activity in other myeloid disorders such as acute myeloid leukemia and myelodysplastic syndrome, as well as in other hematologic malignancies, alone or with other drug combinations. Its value in the context of stem cell support should also be investigated.

Adult↗
PubMed1997

The hyper-CVAD regimen improves outcome in relapsed acute lymphoblastic leukemia.

Sixty-six adults with refractory acute lymphocytic leukemia received salvage therapy with the 'hyper-CVAD' regimen, consisting of eight courses of alternating intensive chemotherapy with growth factor support, followed by oral maintenance chemotherapy. Their outcome was compared with 63 prognostically similar historical control patients treated with high-dose Ara-C plus mitoxantrone with or without GM-CSF. Overall, the complete response rates were similar in the treatment and control groups (29 of 66 (44%) vs 24 of 63 (38%)). There were more patients in the current study with primary resistant disease (10 of 66 (15%) vs one of 63 (2%), P = 0.006), and conversely fewer patients with secondary resistance (19 of 66 (29%) vs 28 of 63 (44%), P = 0.06). Recovery of granulocyte counts above 500/microl was significantly faster in the current study when compared to high-dose Ara-C-treated patients who were given GM-CSF (20 vs 25 days, P = 0.04). Survival was prolonged in the hyper-CVAD-treated patients, with most of the benefit seen in first salvage patients (42 vs 20 weeks, P = 0.016). When only first salvage patients were considered, there was a significant difference in disease-free survival in favor of hyper-CVAD (52 vs 20 weeks, P = 0.008). The hyper-CVAD regimen is a more effective and less toxic salvage regimen for relapsed acute lymphocytic leukemia than high-dose Ara-C-based regimens.

Adult↗
PubMed1997

The IPL gene on chromosome 11p15.5 is imprinted in humans and mice and is similar to TDAG51, implicated in Fas expression and apoptosis.

We searched for novel imprinted genes in a region of human chromosome 11p15.5, which contains several known imprinted genes. Here we describe the cloning and characterization of the IPL ( I mprinted in P lacenta and L iver) gene, which shows tissue-specific expression and functional imprinting, with the maternal allele active and the paternal allele relatively inactive, in many human and mouse tissues. Human IPL is highly expressed in placenta and shows low but detectable expression in fetal and adult liver and lung. Mouse Ipl maps to the region of chromosome 7 which is syntenic with human 11p15.5 and this gene is expressed in placenta and at higher levels in extraembryonic membranes (yolk sac), fetal liver and adult kidney. Mouse and human IPL show sequence similarity to TDAG51 , a gene which was shown to be essential for Fas expression and susceptibility to apoptosis in a T lymphocyte cell line. Like several other imprinted genes, mouse and human IPL genes are small and contain small introns. These data expand the repertoire of known imprinted genes and will be helpful in testing the mechanism of genomic imprinting and the role of imprinted genes in growth regulation.

Amino Acid Sequence↗
PubMed1997

Does occupational exposure to brown coal dust cause a decline in lung function?

OBJECTIVES: To determine if the rate of change in forced expiratory volume in one second (FEV1) in subjects with high exposure to Latrobe Valley brown coal dust was significantly greater than the rate of change among subjects with low exposure. METHODS: A retrospective dynamic cohort design with variable time windows. This study was conducted over a period of 14 years from 1980 to 1994 and used data collected by the State Electricity Commission (SEC) Lung Function Unit for an asbestos surveillance programme. The subjects were exposed to low, medium, or high levels of coal dust. Basic spirometry with wedge bellows spirometers was used to assess lung function. A general linear model (GLM) was used to assess the effects of smoking and exposure to coal dust upon the change in forced expiratory volume in one second (FEV1) while adjusting for age and height. RESULTS: The mean (95% confidence interval (95% CI) rate of decline in FEV1 was 40 (36 to 44) ml/year. Age was a significant predictor of change. A significant effect was found for smoking (P = 0.02) and for exposure to coal dust (P = 0.008). The only significant difference with exposure to coal dust was between the high and mixed exposure categories. CONCLUSION: There is no convincing evidence of excessive decline in FEV1 with exposure to coal dust > 0.75 mg/m3. The absence of a dose response relation provides some evidence against a causal relation. On the basis of this study, reduction of the exposure standards currently applied to brown coal dust in the Victorian electricity industry is not warranted to prevent respiratory disease.

Age Factors↗
PubMed1997

Treatment of newly diagnosed acute promyelocytic leukemia without cytarabine.

PURPOSE: To determine the effect of omission of cytarabine (ara-C) from treatment of newly diagnosed acute promyelocytic leukemia (APL), which allows administration of more anthracycline. PATIENTS AND METHODS: Induction consisted of all-trans retinoic acid (ATRA) 45 mg/m2 daily until complete remission (CR) and idarubicin 12 mg/m2 daily for 4 days beginning on day 5 of ATRA. Patients in CR received two courses of idarubicin 12 mg/m2 daily for 3 days and then, until 2 years post-CR date, alternated three cycles of mercaptopurine, vincristine, methotrexate, and prednisone (POMP) with one cycle of idarubicin 12 mg/m2 daily for 2 days. Results in the 43 patients treated (41 with t(15;17) on standard or Southern analysis) were compared with those in 57 historic newly diagnosed APL patients given ara-C with either doxorubicin, amsacrine (AMSA), or daunorubicin without ATRA, using logistic and Cox regression to assess effects of non-treatment-related covariates on patient outcomes. RESULTS: The CR rate in the current group was 77% (95% confidence interval [CI], 62% to 88%) and was not significantly different from the historic rate. In contrast, disease-free survival (DFS) in CR is superior in the current group (probability at 1 year 0.87; 95% CI, 0.73 to 1.0). This has translated into superior overall DFS for the current group (P = .03 adjusting for the predictive covariates initial WBC and platelet count; 1-year DFS probability 0.67; 95% CI, 0.52 to 0.82; median follow-up 102 weeks). The current treatment appears better both in patients with and without t(15; 17) on standard cytogenetic analysis. CONCLUSION: Given the difficulties inherent in comparing sequential studies and recognizing the multiple differences in treatment between current and historic groups, our results suggest that a large randomized trial incorporating use of ATRA should assess the utility of omitting ara-C from treatment of newly diagnosed APL, thus allowing delivery of more anthracycline.

Adolescent↗
PubMed1997

Phase I study of mitoxantrone plus etoposide with multidrug blockade by SDZ PSC-833 in relapsed or refractory acute myelogenous leukemia.

PURPOSE: Expression of the multidrug resistance gene (MDR1) p170 protein is frequent in leukemic blasts from patients with relapsed acute myelogenous leukemia (AML). A phase I study using the nonimmunosuppressive MDR1 blocker SDZ PSC-833 (PSC) in combination with mitoxantrone (MITO) and etoposide (VP) was performed. PATIENTS AND METHODS: Starting doses (LVL0) of MITO (3.25 mg/m2/d on days 1 and 3 to 6) and VP (210 mg/m2/d on days 1 and 3 to 5) were 40% of the maximal-tolerated dose (MTD) from a prior study. A 1.5-mg/kg loading dose of PSC was followed by a 120-hour continuous infusion of 10 mg/kg/d on days 2 to 6. Blood samples for PSC, MITO, and VP pharmacokinetics (PK) were taken on days 1 and 3, and samples for MDR1 expression were taken on day 0. RESULTS: Severe mucositis developed in all patients at LVL0; therefore, MITO and VP doses were reduced to 2.5 and 170 mg/m2 (LVL-1) for the next seven patients, and this dose proved to be MTD. All LVL0 and three LVL-1 patients had transient elevations in the serum bilirubin level to > or = 4 mg/dL. Serum creatinine level increased to greater than 2 mg/dL in one case. There were no other grade 3 or 4 nonhematologic toxicities observed. The peripheral blood was cleared of leukemia in three LVL0 and four LVL-1 patients. The marrow was cleared of leukemic cells in one LVL0 and five LVL-1 patients, and a significant reduction in marrow leukemic infiltrate was observed in eight of 10. No patient achieved complete remission (CR), and all died of progressive disease (n = 8) or infection (n = 2). MDR1 expression was detected by fluorescent-activated cell sorter (FACS) analysis in five of seven cases. An elevated MDR1 mRNA level was detected by quantitative polymerase chain reaction (Q-PCR) in six of eight cases studied. Clearing of leukemia cells from the marrow occurred in four of six MDR1-positive and one of three MDR1-negative patients. Despite the fact that LVL0 doses had to be reduced due to toxicity, coadministration of PSC did not produce a consistent effect on MITO PK; however, it did repeatedly lead to increased levels of VP in the serum. CONCLUSION: We conclude that PSC-MITO-VP is a tolerable regimen with antileukemic activity. Addition of PSC necessitated a 66% reduction in MITO and VP doses from a prior study without PSC.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

A buccal mucosal harvesting technique for urethral reconstruction.

PURPOSE: A step-by-step harvesting technique for buccal mucosa is described that maximizes graft yield while minimizing potential donor site morbidity in urethral reconstruction. MATERIALS AND METHODS: A specialized oral retractor was used to expose and retract the buccal mucosal lining of the oral cavity for graft harvesting in 12 patients. RESULTS: Adequate buccal mucosal graft size was obtained for each reconstruction. There were no oral donor site or urethral recipient site complications. CONCLUSIONS: This harvesting technique offers a simple and effective method for optimizing buccal mucosal graft harvests.

Adult↗
PubMed1997

Tallimustine, an effective antileukemic agent in a severe combined immunodeficient mouse model of adult myelogenous leukemia, induces remissions in a phase I study.

Despite progress in leukemia therapy, only 20-30% of patients with acute myelogenous leukemia (AML) are cured. 1-beta-D-arabinofuranosylcytosine- and topoisomerase II-reactive drugs are the primary therapeutic agents used. The aim of this study was to evaluate the potential activity of tallimustine in leukemia. In this study, we first investigated the efficacy and toxic effects of tallimustine, a distamycin-A derivative, in a human leukemia model in severe combined immunodeficient (SCID) mice. On the basis of its dramatic activity in this preclinical study, a Phase I study of tallimustine at a starting dose of 300 microgram/m2/day for 3 days every 3-4 weeks was conducted in patients with refractory or relapsed leukemia. In SCID mice grafted with a human myelomonocytic leukemia cell line, tallimustine resulted in complete remission of disease in most mice at tolerable dosages ranging from 0.86 to 3.0 mg/kg/day for 3 days and was combined effectively and safely with a 2-day schedule of high-dose ara-C. In the Phase I study, 26 patients with refractory or relapsed leukemia were treated. The maximum tolerated dose was 900 microgram/m2/day for 3 days every 3-4 weeks. This dose was 3 times higher than the maximum tolerated dose in solid tumors and was limited by severe mucositis. Magnesium and potassium wasting were also observed, but other side effects (fatigue and gastrointestinal) were minor. Two (8%) patients with AML achieved complete remission and two achieved hematological improvement with persistent thrombocytopenia. The results of this study indicate that tallimustine has promising activity in AML. Future studies may combine tallimustine with other agents known to be active against AML, and investigate its activity in other hematological malignancies. The recommended Phase II single-agent dose of tallimustine is 750-900 microgram/m2/day for 3 days, and combination studies may start at 50-66% of this dose schedule. The SCID mouse model of human leukemia may be promising in the preclinical evaluation and selection of potential antileukemic agents.

Adolescent↗
PubMed1996

Topotecan, a topoisomerase I inhibitor, is active in the treatment of myelodysplastic syndrome and chronic myelomonocytic leukemia.

The aim of this study was to evaluate the activity of topotecan in patients with myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). Forty-seven patients with a diagnosis of MDS (n = 22) or CMML (n = 25) were treated. The median age was 66 years. Chromosomal abnormalities were present in 70% and thrombocytopenia less than 50 x 10(3)/microL in 51%. Evaluation of outcome and of differences among subgroups was performed according to standard methods; the criteria for response were those used for acute leukemia. Topotecan was administered as 2 mg/ m2 by continuous infusion over 24 hours daily for 5 days (10 mg/m2 per course) every 3 to 4 weeks until remission, then once every month for a maximum of 12 courses. Thirteen patients (28%) achieved a complete response (CR) and six (13%) had hematologic improvement. A CR was achieved in six of 22 patients with MDS (27%) and in seven of 25 with CMML (28%). All eight patients who presented with cytogenetic abnormalities (five chromosome 5 or 7 abnormalities) who achieved CR were cytogenetically normal in CR. Characteristics for which there was evidence of association with a higher response rate were lack of prior chemotherapy, less than 10% marrow monocytes, and absence of RAS oncogene mutations. In contrast, CR rates were similar in patients with or without abnormal karyotypes. Mucositis occurred in 64% of patients (severe in 19%) and diarrhea in 32% (severe in 13%). Febrile episodes occurred in 85% of patients and documented infections in 47%. With a median follow-up duration of 8 months, the 12-month survival rate was 38%, median survival time 10.5 months, and median remission duration 7.5 months. We conclude that topotecan has significant activity in MDS and CMML, with acceptable side effects. Future studies will investigate topotecan combined with topoisomerase II reactive agents, cytarabine, or hypomethylating agents (azacytidine and decitabine).

Adult↗
PubMed1996

Apoptosis sensitivity in chronic lymphocytic leukemia is determined by endogenous endonuclease content and relative expression of BCL-2 and BAX.

Therapeutic agents used in the treatment of chronic lymphocytic leukemia (CLL) are capable of inducing apoptosis in some (but not all) patient isolates. It is not yet clear whether cells that are resistant to one agent will also be resistant to others, and the mechanisms contributing to differential apoptosis sensitivity are not known. Here we report that glucocorticoid hormone and a clinically relevant chemotherapy combination (fludarabine plus mitoxantrone) fail to induce apoptosis in four of 24 CLL patient isolates. Apoptosis resistance was associated with elevated BCL-2 and BAX expression. Interestingly, incubation in vitro led to down-regulation of BCL-2 expression in both apoptosis-sensitive and apoptosis-resistant cells, whereas parallel down-regulation of BAX occurred only in the resistant samples. Evaluation of nuclear endonuclease content indicated that all of the apoptosis-sensitive samples contained appreciable levels of activity, whereas the endonuclease was not detected in the four populations of resistant cells. Our results indicate that nuclear endonuclease activity represents an excellent prognostic indicator of CLL apoptosis sensitivity that may be controlled by differential BCL-2 family polypeptide expression and signals from the in vivo microenvironment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Acute lymphoblastic leukemia with myeloperoxidase activity.

The French-American-British (FAB) classification of acute leukemias is based on the light microscopic detection of myeloperoxidase (MPO) activity in blast cells. Cells with MPO activity in > 3% of cells are classified as acute myeloid leukemia (AML) and usually express myeloid cell surface antigens. We describe a case of acute leukemia in which the blast cells have lymphoid morphology, ultrastructure, immunophenotype, and molecular rearrangements, but express significant amounts of MPO. We discuss the incidence, features, and outcome of MPO-positive acute lymphoblastic leukemia (ALL).

Adult↗
PubMed1996

Fludarabine, mitoxantrone, and dexamethasone: an effective new regimen for indolent lymphoma.

PURPOSE: Although most patients with indolent lymphomas respond to initial therapy, virtually all experience relapse. Secondary therapy is often beneficial, but responses are rarely, if ever, durable. We conducted this phase II trail to evaluate the therapeutic efficacy and toxicity of fludarabine, mitoxantrone, and dexamethasone (FND) in patients with relapsed indolent lymphoma. PATIENTS AND METHODS: Fifty-one patients with recurrent or refractory indolent lymphoma were treated with a regimen of fludarabine 25 mg/m2/d intravenously (IV) on days 1 to 3, mitoxantrone 10 mg/m2 IV on day 1, and dexamethasone 20 mg/d IV or orally on days 1 to 5. Treatment was repeated at 4-week intervals for a maximum of eight courses. Late in the course of this trial, trimethoprim-sulfamethoxazole (TMP-SMX) was incorporated for Pneumocystis carinii (PCP) prophylaxis. RESULTS: Responses were complete (CR) in 24 patients (47%) and partial (PR) in 24 (47%). The median failure-free survival time was 21 months for CR patients and 9 months for PR patients. Notable activity of FND was seen even in the elderly, in those with high serum lactate dehydrogenase (LDH) or beta2-microglobulin levels, and in those with multiple prior treatment regimens. The predominant toxic effects were myelosuppression and infections; other toxic effects were modest. Infections occurred in 12% of courses. Almost half of the infections were proven or suspected opportunistic infections, including six cases of dermatomal herpes zoster and two cases of proven PCP pneumonia. CONCLUSION: The FND combination is highly active in patients with recurrent or relapsed indolent lymphoma and results in a high percentage of CRs. Because of the risk of opportunistic infections, we currently recommend prophylaxis with TMP-SMX and advise deletion of corticosteroids for patients who develop opportunistic infections.

Aged↗
PubMed1996

Disseminated intravascular coagulation in adult acute lymphoblastic leukemia: frequent complications with fibrinogen levels less than 100 mg/dl.

In order to establish the frequency and clinical complications of DIC during remission induction of untreated adults with acute lymphoblastic leukemia, we retrospectively reviewed the records of 125 consecutive patients treated with vincristine, doxorubicin, and dexamethasone but without L-asparaginase. DIC, defined as hypofibrinogenemia in the presence of elevated fibrin-fibrinogen degradation products, was detected at presentation in 10% of 99 and during remission induction in 67% of 58 patients who were screened for DIC. Elevated levels of D-dimers (DD) were seen in all eight patients with DIC in whom they were measured. All cases of DIC were diagnosed by the ninth day of induction and were associated with infection in 15 of 39 patients. DIC did not cause any deaths but was temporally associated with two thromboses and four hemorrhages in six of the 16 patients with fibrinogen levels < 100 mg/dl but with only one hemorrhage among 23 patients (4%) with fibrinogen levels > 100 mg/dl (P < 0.01). Heparin was not administered to any patient, whereas platelets were administered to all to maintain platelet counts > 20 x 10(9)/l. Fresh frozen plasma (FFP) and/or cryoprecipitate were administered 26 patients resulting in a contemporaneous correction of the coagulopathy and in control of hemorrhages and thromboses. We conclude that DIC is rare at presentation but common during induction of adult ALL and is frequently associated with clinical complications when fibrinogen levels are < 100 mg/dl. We recommend daily testing of fibrinogen, PT, and DD during the first 10 days of induction, and for the patients with DIC platelet transfusions to maintain counts > 20 x 10(9)/l, and when fibrinogen levels fall below 100 mg/dl transfusions of FFP and/or cryoprecipitate. Additional studies are needed to determine the optimal management of the DIC during remission induction of adult acute lymphoblastic leukemia.

Adult↗
PubMed1996

Secondary acute promyelocytic leukemia. Characteristics and prognosis of 14 patients from a single institution.

The aims of this study were to analyze the characteristics and outcome of patients with secondary acute promyelocytic leukemia (APL) and compare them to those with primary APL. One hundred and thirteen patients referred to our service with a diagnosis of APL were reviewed. Fourteen were classified as secondary APL. Nine were induced with chemotherapy, and five with all-trans retinoic acid plus chemotherapy. Pretreatment characteristics, response to therapy and outcome of primary vs secondary APL were compared by standard statistical methods. Secondary APL constituted 12% of all APL cases. Patients with secondary APL were significantly older (median age 56 vs 36 years; P < 0.01) and had a lower incidence of hypofibrinogenemia (P < 0.01) than those with primary APL. The complete response (CR) rates were similar with secondary vs primary APL (CR rates 79 vs 69%), as were CR duration and survival. The CR rates at 5 years were 57 and 45%, respectively(P not significant), and the survival rates 37 and 35%, respectively (P not significant). The incidence of secondary APL within APL disease (12%) was similar to the incidence of secondary acute myeloid leukemia (AML) in karyotypes not known to be therapy-related (diploid, t(8;21), inversion 16: incidences 9 to 12%), but was significantly lower than in karyotypes known to be therapy-related (chromosome 5 or 7 abnormalities, 11q; incidences 30 and 33%). We conclude that secondary APL has general characteristics and outcome similar to primary APL. it is more likely a second primary rather than therapy-related AML, and should be treated in a manner similar to primary APL.

Adult↗