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Biomedical subjects

H Ekert

Publications and source records attributed to H Ekert.

At least 37 records · Page 2Linked to original sources
PubMed1993

Results of intensive therapy in childhood acute myeloid leukemia, incorporating high-dose melphalan and autologous bone marrow transplantation in first complete remission.

Childhood acute myeloid leukemia (AML) has a poor prognosis with standard chemotherapy. Allogeneic bone marrow transplantation (BMT) in remission improves the outlook only for the one third of patients with sibling donors. Autologous BMT with a lower morbidity and mortality is available to all. In this study, maximum cytoreduction was achieved by intensive early chemotherapy. Final intensification, with autologous BMT was offered to all those remaining in first complete remission (CR). Patients received two induction and two consolidation courses of intensively scheduled chemotherapy. Cytoreduction was assessed on day 14 and remission was assessed after courses 2 and 4. Bone marrow was harvested after recovery from the second consolidation course or after the first maintenance course and separated on a discontinuous percoll gradient before cryopreservation. Twenty-eight of 31 consecutively enrolled patients achieved CR. Three relapsed early and, of the 25 eligible, 24 underwent autologous BMT. Twenty-three patients received high-dose melphalan and 1 received busulphan and cyclophosphamide before autologous BMT at a median of 113 days (range, 86 to 301) after initial CR. Trilineage engraftment occurred in all. Neutrophil recovery to greater than 0.5 x 10(9)/L occurred at a median of 46 days (range, 13 to 92) after autologous BMT. Platelet recovery was delayed, with a median time to achieve greater than 20 x 10(9)/L of 42 days (range, 18 to 215). With a minimum follow up of 25 months following autologous BMT only 3 children have relapsed. The 5-year event-free survival rate (EFS) from diagnosis is 68% (95% confidence interval, 46% to 90%). Five-year EFS following autologous BMT is 87% (95% confidence interval, 67% to 100%). Autologous BMT with high-dose melphalan administration after intensive chemotherapy has produced EFS equivalent to allogeneic BMT and is associated with a strikingly low relapse rate. High-dose melphalan appears to be a valuable agent for conditioning therapy in AML.

Acute Disease↗
PubMed1993

A pilot study of EVAP/ABV chemotherapy in 25 newly diagnosed children with Hodgkin's disease.

Twenty five children with newly diagnosed Hodgkin's disease were clinically staged and treated with a chemotherapy protocol designed to reduce delayed toxicity. Four patients without macroscopic residual disease after biopsy received three cycles of hybrid EVAP/ABV. All remain in CR 31-46 months from diagnosis. One other developed fever and rash considered to be due to Ara-C and was treated with MOPP. Twenty patients had macroscopic residual disease after biopsy and were treated with two cycles of EVAP alone and reassessed with imaging and gallium scans. Twelve achieved CR, seven PR and one was not evaluable. Patients in CR were subsequently treated with 2-4 cycles of hybrid EVAP/ABV, while those in PR received 3-4 cycles. At a median follow up of 37 months the overall survival was 100%, relapse free 79% and treatment failure free 60%. Eight patients had mediastinal widening > 1/3 thoracic width. At the completion of the protocol five achieved CR, two PR and one was withdrawn from study at investigator preference. One patient has subsequently relapsed. Of the evaluable ten patients without a mediastinal presentation all achieved CR but three relapsed at 10, 13 and 18 months from diagnosis. Patients who achieved a PR only, relapsed or were withdrawn from study have been salvaged with MOPP or Ch1VPP chemotherapy.

Adolescent↗
PubMed1993

Prognostic significance of detection of monoclonality in remission marrow in acute lymphoblastic leukemia in childhood. Australian and New Zealand Children's Cancer Study Group.

Techniques based on the polymerase chain reaction (PCR) to detect rearrangement of the immunoglobulin or T-cell receptor genes can detect residual disease in leukemia and hence have the potential to improve prognosis and treatment. Such techniques may involve either detection of monoclonality, which is simple and quick but has limited sensitivity, or specific detection of the leukaemic clone, which is complex and time-consuming but has high sensitivity. The PCR was used to detect monoclonal rearrangements of the immunoglobulin heavy chain and/or T-cell receptor gamma chain genes in archival marrow specimens from 185 children with acute lymphoblastic leukemia who achieved remission during two consecutive Australasian trials of treatment. A monoclonal rearrangement was detected at diagnosis in 152 (84%) patients and in these patients detection of the same rearrangement in the remission marrow at the end of induction therapy was highly significantly correlated with outcome. There were nine patients in whom polymerase chain reaction showed only the monoclonal rearrangement and eight (89%) relapsed; there were 26 patients in whom PCR showed the leukemic monoclonal rearrangement as well as polyclonal rearrangements from normal lymphocytes and 12 (46%) relapsed; and there were 117 patients in whom only polyclonal rearrangements could be detected and only 29 (25%) relapsed. In patients who relapsed, remissions were shorter in those patients in whom the leukemic rearrangements had been detected in the remission marrow. Treatment in the later trial was more intensive than in the earlier trial, the results were better and the PCR detected the leukemic rearrangement in the remission marrow in significantly fewer patients. We conclude that detection by PCR of the monoclonal gene rearrangement of the leukemic clone in remission marrow indicates that numerous leukemic cells have survived induction therapy and is a good predictor of relapse. However, due to limited sensitivity of the test, failure to detect the leukemic clone by PCR is not a sufficiently good predictor of ultimate cure.

Bone Marrow↗
PubMed1991

Simple immuno bead labeling of leukemic cell clusters cultured in methylcellulose.

In studies of in vitro leukemic clonogenic cells it is of importance to determine the cell lineage of individual clusters grown in culture. A method is described for the in-situ identification of leukemic cell clusters in methylcellulose cultures. Whole cultures are dried and incubated with various monoclonal antibodies, followed by incubation with beads coated with secondary antibody. Clusters containing antibody-positive cells are heavily labeled with beads which simplifies the recognition and scoring of clusters using normal light microscopy. This method has general applications and can also be used to identify normal myeloid and lymphoid clusters depending on the availability of lineage specific monoclonal antibodies.

Bone Marrow↗
PubMed1990

Zidovudine (AZT) therapy in children with HIV infection: the Australian experience.

Fifteen children (11 males and four females), on oral Zidovudine (AZT) for symptomatic HIV infection were studied retrospectively. Twelve acquired HIV via blood products, two from vertical transmission (maternal intravenous needle sharing) and one through breast feeding. Their mean age at the start of therapy was 8.6 years (s.d. 4.4 years, range 1.8-15.3 years). The main indications for therapy were failure to thrive (FTT) in 10, recurrent respiratory tract infections (RRTI) in eight, and developmental delay (DD) in one, with overlapping indications being Pneumocystis carinii pneumonia (PCP) in one and pulmonary lymphoid hyperplasia (PLH) in two. The mean commencement dose was 24 mg/kg per day orally in 3-6 divided doses (range 16-35 mg/kg per day). The duration of therapy was 2 weeks-2 1/2 years. Significant improvement in growth was observed by 2 months; at 6 months, growth was sustained in these otherwise ill children, with only two falling below pretreatment weight. Decrease in the frequency of RRTI based on subjective reports of the attending clinicians was observed in seven of the eight evaluable children still on therapy. Improvement in PCP and PLH occurred in two children and modest improvement was subjectively reported in PLH in one while still early in the course of therapy. Overall, AZT was well tolerated. Dose modifications were for neutropenia in three (of which only two were drug related), rapidly falling neutrophil count in one, anaemia in two (with concurrent history of chronic gastrointestinal tract blood loss in one), severe GIT irritation in one and transient sedation in one. Seven opportunistic infections were reported (three in the same patient) of which two occurred following cessation of therapy, one after only 2 weeks of therapy, and one had not been on primary prophylactic therapy. Three deaths occurred, one associated with opportunistic infections and two while off therapy (one respiratory failure, one PCP).

Adolescent↗
PubMed1990

Prevention of cyclophosphamide/cytarabine-induced emesis with ondansetron in children with leukemia.

Ondansetron, a 5HT3 antagonist, was given to 20 children aged 4 to 18 years who were undergoing treatment with the Australian and New Zealand Childhood Cancer Study Group Acute Lymphocytic Leukaemia (ALL) Study V Protocol. The study was open, dose ranging, and noncomparative, and designed to evaluate safety and efficacy of ondansetron in preventing nausea and vomiting caused by cyclophosphamide intravenous (IV) 1,000 mg/m2 day 1, and cytarabine IV subcutaneously (SC) 75 mg/m2 on days 2 to 5. Ten patients were given ondansetron 5 mg/m2 IV (group A) and subsequently another 10 patients were given ondansetron 3 mg/m2 IV (group B). Oral ondansetron was given for 14 doses, at the same dosage for both groups, commencing simultaneously with the IV infusion and continuing at 8 hourly intervals, ie, until day 5. The oral dose was based on surface area with the following schedule: 0.3 to 0.6 m2, 2 mg; 0.6 to 1 m2, 3 mg; and greater than 1 m2, 4 mg. Vomiting on the first day of chemotherapy was reported in group A by one patient and by one patient in group B. Vomiting during days 2 to 5 was reported by two group-A patients and by three group-B patients. Nausea was recorded on day 1 by one patient in group A, and two in group B, and on days 2 to 5 by three patients in group A, and by seven in group B. All patients were alert during treatment with ondansetron and there was no dystonia. There were no changes in renal function or hematology values that could be ascribed to the study drug. Transient elevations in bilirubin and liver enzymes were observed. We conclude that our results indicate that ondansetron is a safe and extremely effective single-agent antiemetic with minimal side effects, when administered both IV and orally.

Administration, Oral↗
PubMed1990

Selection of two human bone marrow stromal cell subpopulations with different effects on the maintenance and differentiation of myeloid progenitor cells.

The simple selection of two human bone marrow stromal cell populations is described. Adherent stromal cell layers were formed in primary cultures of low-density marrow cells. At time of confluence, persistent nonadherent cells were collected and transferred to new culture flasks, where they formed a secondary stromal layer. These primary and secondary stromal layers differed in their ability to support myelopoiesis, as tested by progenitor cell production after inoculation with fresh bone marrow cells. In the presence of primary stromal layers the number of granulocyte-macrophage colony-forming cells (GM-CFC) decreased gradually, but in the presence of secondary layers production of GM-CFC was evident during the first 3 weeks. The regulation of the two stromal types on hemopoietic cell proliferation and differentiation was investigated by determining the kinetics of the transitions within the differentiation sequence of three myeloid progenitor cells. Pre-CFC, day-14 CFC, and day-7 CFC were fractionated by cell sorting on the basis of forward light scatter and cocultured with the two stromal layer types. It was found that the decrease in CFC numbers in the presence of primary stromal layers could be explained by the stimulation of hemopoietic cells into rapid differentiation with loss of proliferative capacity at an early stage of culture. Secondary layers appeared to promote survival and self-renewal of later types of progenitor cells and to trigger more immature cells to proliferate and differentiate at a later time of culture.

Bone Marrow Cells↗
PubMed1989

Infectious diarrhea in children undergoing bone-marrow transplantation.

Fecal flora of 12 children undergoing bone-marrow transplantation was monitored prospectively using comprehensive microbiological techniques. Diarrhea developed at least once in ten of the 12 children (83%), and a total of 24 episodes were recorded. Recognised gut pathogens were isolated from 11/21 (52%) diarrheal episodes where fecal specimens were obtained. Enteric pathogens identified included viral pathogens in 19% (rotaviruses, 'enteric' adenoviruses), parasites in 19% (cryptosporidium, Giardia lamblia) and cytotoxic C. difficile (14%). Excretion of clostridial species (including cytotoxin negative C. difficile, C. innocuum) occurred in 90% of diarrheal episodes when no enteric pathogen was identified. These results suggest that infection is often responsible for diarrhea associated with bone-marrow transplantation. Prophylaxis against enteric infection might reduce the morbidity and mortality associated with severe diarrhea in bone-marrow transplanted children.

Adolescent↗
PubMed1988

Prospective study of childhood acute lymphocytic leukemia: hematologic, immunologic, and cytogenetic correlations.

We studied the karyotype in 81 consecutively diagnosed children with acute lymphocytic leukemia (ALL) treated at one institution on a randomized treatment protocol. In 75 patients (93%), a morphological cytogenetic result was obtained, and 57 (65%) were successfully G-banded. Of the 75 patients, 46 (61%) showed abnormal chromosomes, mainly hyperdiploidy and pseudodiploidy, and 29 had no detectable abnormality. Our findings confirmed that the karyotype has prognostic significance. Duration of complete remission was 93% at 42 months for patients with high hyperdiploidy (greater than 50). For patients with an apparently normal karyotype, it was 58%; and for patients with structural abnormalities it was 15%. The significance of these findings was confirmed by multivariate analysis, which showed age and karyotype to be the most important determinants of duration of remission.

Child↗
PubMed1988

Treatment with MOPP or ChlVPP chemotherapy only for all stages of childhood Hodgkin's disease.

Fifty-three children with Hodgkin's disease were clinically staged and treated with chemotherapy alone. Forty-six received mechlorethamine (Mustargen; Merk Sharpe & Dohme, West Point, PA), vincristine (Oncovin; Eli Lilly and Company, Indianapolis), procarbazine, and prednisolone (MOPP) and 7 chlorambucil, vinblastine, prednisolone, and procarbazine (ChlVPP). There were four events in the 38 children with stage I and II disease. One patient with massive mediastinal disease failed to remit and subsequently failed mantle irradiation and changes of chemotherapy. Another relapsed at the site of local disease and was salvaged with involved field irradiation and further courses of MOPP. Two other children died as a result of acute graft-v-host disease (GVHD) following transfusion. At autopsy there was no evidence of Hodgkin's disease. Fifteen children had stage III and IV disease and 14 achieved complete remission (CR) and none have relapsed. The child who failed to achieve remission died of virus infections. A mediastinal mass greater than 1/3 the thoracic width was present in 19 children of whom 18 achieved remission and none relapsed. An infradiaphragmatic presentation occurred in eight, all achieved remission and none relapsed. Overall at a median follow-up time of 45 months survival was 94%; the percent of patients without treatment failure was 92; and the percent without relapse was 98.

Adolescent↗
PubMed1987

Long-term results of the treatment of children with factor VIII inhibitors with prothrombin-complex concentrates.

Twelve boys with haemophilia and factor VIII inhibitors have received initial treatment for each episode of bleeding with prothrombin-complex concentrate. The follow-up period for these boys has ranged from two months to 14 years, and a total of 732 bleeding episodes were reviewed. Each boy underwent a full clinical and radiological assessment of knee-joint function, and this was compared with knee-joint function in 29 patients with severe haemophilia but without factor VIII antibodies. A change of treatment from prothrombin-complex concentrate to some other form of therapy was considered to be required in only 4% of the bleeding episodes. Of 10 severe bleeding episodes, five episodes clearly were controlled with prothrombin-complex concentrate, but five episodes necessitated alternative treatment. Four of the 12 families considered prothrombin-complex concentrate as relatively ineffective. All boys who were older than 10 years of age showed grade-1 or grade-2 impairment of knee-joint mobility, as well as radiological evidence of moderate-to-severe knee-joint changes. In the group of haemophiliac patients who were older than 10 years of age and did not have factor VIII antibodies, only 10 of the 58 knee-joints that were examined showed grade-1 or grade-2 functional impairment. Although prothrombin-complex concentrates were effective in the control of the majority of minor bleeding episodes, they were effective in only 50% of severe episodes of bleeding and did not prevent the early development of haemophilic arthropathy.

Blood Coagulation Factors↗
PubMed1987

Hypereosinophilia syndrome with pneumonia in acute lymphoblastic leukaemia.

Eosinophilic pneumonia in association with acute lymphoblastic leukaemia (ALL) is very rare. A teenage boy is described with eosinophilic pneumonia which preceded by several months the onset of ALL. Prior to establishment of the diagnosis he had been treated with corticosteroids with a transient response only. This delayed his final diagnosis until there were haematologic features of leukaemia. The leukaemic blasts were cALLA (CD10) positive and had a normal chromosome number with no translocations on banding studies. The pneumonia remitted rapidly when his leukaemia responded to chemotherapy.

Adolescent↗