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Biomedical subjects

C Aul

Publications and source records attributed to C Aul.

At least 73 records · Page 4Linked to original sources
PubMed1998

Superiority of high-dose over intermediate-dose cytosine arabinoside in the treatment of patients with high-risk acute myeloid leukemia: results of an age-adjusted prospective randomized comparison.

Although cytosine arabinoside (AraC) represents the most effective single agent in the treatment of adults with acute myeloid leukemia (AML) when given at doses exceeding 200 to 500 mg per application, its optimal dosage is still a matter of controversial discussion. While pharmacokinetic investigations suggest that the AraC-activating enzyme deoxycytidine kinase is saturated at drug concentrations achieved by short-term infusion of 0.5 to 1.0 g/m2 AraC and that higher doses are therefore not more effective, recent evidence indicates that additional mechanisms of AraC cytotoxicity may exist which could be enhanced by further dose escalation. In order to test this thesis in the clinical setting, a prospective randomized comparison of high-dose (HD-AraC) vs intermediate-dose (ID-AraC) AraC was carried out in patients with refractory or relapsed AML on the basis of the sequential high-dose AraC and mitoxantrone regimen (S-HAM). AraC was given as a 3-h infusion q 12 h on days 1, 2, 8 and 9. Patients younger than 60 years were randomized to AraC doses of 3.0 g/m2 vs 1.0 g/m2 while older patients received either 1.0 g/m2 or 0.5 g/m2 per single dose. Mitoxantrone was given to all patients on days 3, 4, 10 and 11 at a daily dose of 10 mg/m2. Randomization was stratified for primary refractoriness against induction therapy and length of first remission in relapsed patients. From 186 evaluable patients, 88 (47%) and 10 cases (5%) achieved a complete (CR) or partial (PR) remission, 39 patients (21%) had persisting leukemia (non-response (NR)), and 49 cases (26%) died within 6 weeks after the start of therapy (early death (ED)). In patients younger than 60 years the higher dose level resulted in a significant reduction of NR (12% vs 31%; ordinal chi2 test: P = 0.01) but also a higher rate of ED (32% vs 17%) thus leading to a marginally higher CR rate only (52% vs 45%). Within the subgroup of patients with refractory AML the tendency towards a higher CR rate after HD-AraC was more pronounced (46% vs 26%; P = 0.045). In patients older than 60 years, corresponding though less evident differences were observed with a higher rate of NR in the lower dose group (26% vs 16%) and ED occurring more frequently after higher doses (36% vs 26%). These data indicate that HD-AraC reveals a significantly higher antileukemic efficacy than ID-AraC as expressed by a significant reduction of failure from NR. This advantage, however, does not fully translate into an increase in remission rate due to a higher incidence of ED after HD-AraC predominantly from uncontrolled infections. In order to take full advantage of the higher antileukemic activity of HD-AraC an improvement of supportive care and infection control is warranted.

Acute Disease↗
PubMed1998

Haemolytic-uraemic syndrome and thrombotic-thrombocytopenic purpura in adults: clinical findings and prognostic factors for death and end-stage renal disease.

BACKGROUND: Left untreated, haemolytic-uraemic syndrome (HUS) and thrombotic-thrombocytopenic purpura (TTP) in adults have a poor prognosis with mortality rates reaching 90%. Patients who survive often develop end-stage renal disease. Because of similarities in clinical and morphological findings, both diseases are considered as one entity referred to as HUS-TTP syndrome. METHODS: From 1974 to January 1995, 45 adult patients received treatment for HUS-TTP at our clinic. By stepwise logistic regression analyses, we examined how known risk factors and plasma exchange with fresh-frozen plasma (PE) influenced mortality and end-stage renal disease. RESULTS: Three of 45 patients died (7%). Though we were not able to find significant predictors of mortality, low haemoglobin levels (5.93 +/- 0.32 vs 9.10 +/- 2.16 g/dl) and high leukocyte counts on admission (15.830 +/- 3.690 vs 11.150 +/- 4.580 microliters-1) appeared to indicate an unfavourable outcome. Regarding the development of end-stage renal disease, PE proved to be the only favourable indicator (P = 0.0001). PE was performed in 30 patients 3-20 times (9.2 +/- 4.8, mean +/- SD). Of 28 surviving patients treated with PE, only four developed end-stage renal disease, whereas dialysis was necessary in 11 of 14 patients not treated with PE. Application of PE led to an 81.8% reduction of the relative risk of developing end-stage renal disease. An additional prognostic influence of other potential risk factors such as age, sex, platelet count on admission, lactate dehydrogenase serum levels, serum creatinine, blood pressure, prodromal disease, and renal histology was not found. CONCLUSION: This retrospective clinical study confirms the therapeutic value of plasma exchange with fresh-frozen plasma to maintain renal function in patients with HUS-TTP.

Adolescent↗
PubMed1998

Plasma levels of D-dimer and circulating endothelial adhesion molecules in veno-occlusive disease of the liver following allogeneic bone marrow transplantation.

Veno-occlusive disease (VOD) of the liver is a frequent and life-threatening complication of BMT. Recently, successful treatment by t-PA has been reported but has been compromised by fatal bleeding events. Therefore, t-PA application should be restricted to patients with severe VOD. However, moderate and severe forms of VOD are difficult to distinguish in early stages. We analyzed plasma levels of cross-linked fibrin degradation products (D-dimer) and soluble endothelial adhesion molecules such as sE-selectin, sVCAM-1 and sICAM-1 in 10 consecutive patients undergoing allogeneic BMT to evaluate their use in identifying severe forms of VOD. During the observation period, 4 episodes of VOD occurred, 2 of which were fatal due to early onset of multiorgan failure. Concentrations of D-dimer generally increased after transplantation. However, there was an additional significant increase in D-dimer levels during severe VOD. Thus, D-dimer levels above 1000 microg/l were only found in 2 cases with severe VOD and fatal outcome. When compared with bilirubin concentrations substantial increases of D-dimers appeared earlier during the course of severe VOD. In contrast, VOD episodes were not accompanied by significant increases in sE-selectin, sVCAM-1 and sICAM-1 levels. It is concluded that measurement of D-dimer concentrations may aid accuracy to the early diagnosis of severe VOD.

Adult↗
PubMed1998

Dyshematopoiesis in de novo acute myeloid leukemia: cell biological features and prognostic significance.

Dyshematopoiesis was found in 44 (42.3%) of 104 cases of de novo acute myeloid leukemia (AML). Dyshematopoietic AML (dys-AML) and AML without hematopoietic dysplasia (non-dys-AML) were compared with regard to biological, hematological, immunophenotypic, and cytogenetic parameters as well as prognostic criteria. Median age of patients was 55 years in both groups. In dys-AML, the median leukocyte count (p = 0.04), peripheral blast (p = 0.02) and medullary blast cell count (p < 0.001) were significantly decreased, whereas the median platelet count (p - 0.04) was increased. Immunophenotyping demonstrated that leukemic blast cells in dys-AML more frequently expressed the adhesion molcules CD54 (p = 0.05) and CD58 (p = 0.08) than leukemic cells in non-dys-AML. Cytogenetically, we distinguished two karyotypic patterns, one group with a normal karyotype or prognostically favorable single chromosome aberrations ("P(0)-karyotype"), and another one with unfavorable single aberrations or complex aberrations ("P(1)-karyotype"). The incidence of these groups was not significantly different between dys-AML and non-dys-AML. Complete remission rate (CRR) after induction chemotherapy (p = 0.03) and overall survival time (OS; p = 0.03) were significantly lower in dys-AML. In addition, median disease free survival (DFS; p = n.s.) was inferior compared to non-dys-AML. In the dys-AML as well as in the non-dys-AML patient group, CRR, DFS, and OS were decreased in the P(1)-compared to the P(0)-subgroup. We conclude that dyshematopoietic AML is characterized by specific cell biological features and that hematopoietic and cytogenetic status represent complementary prognostic factors in de novo AML.

Acute Disease↗
PubMed1998

Pathogenesis, etiology and epidemiology of myelodysplastic syndromes.

BACKGROUND AND OBJECTIVE: The myelodysplastic syndromes are common hematological malignancies affecting predominantly elderly people. Patients usually present with chronic cytopenias which gradually worsen due to progressive bone marrow failure or transformation into acute myeloid leukemia. Disease prevention is more cost-effective than therapeutic intervention and the establishment of the etiology and pathogenesis of MDS therefore assumes considerable importance. This review will outline current concepts of the pathobiology of MDS, putative etiological insults and the mechanisms of disease initiation as well as recent contributions to the descriptive epidemiology of these disorders. EVIDENCE AND INFORMATION SOURCES: The authors of the present review have a long-standing interest in the pathogenesis, etiology and epidemiology of MDS. Journal articles covered by the Science Citation Index and Medline have been reviewed and personal experience and discussion with international experts collated. STATE OF THE ART AND PERSPECTIVES: The initiation processes for the development of MDS remain unknown. A poorly defined transforming event affects a pluripotent or multipotent progenitor cell in the bone marrow, conferring a growth advantage upon it and eventually establishing clonal hematopoiesis. An important pathogenetic mechanism in MDS is premature intramedullary cell death via excessive apoptosis, explaining the apparent paradox of a cellular marrow in combination with peripheral cytopenias (ineffective hematopoiesis). Therapy-related MDS/AML following exposure to alkylating agents is the only clear etiological factor thus identified. Increasing evidence for exposure to benzene and radiation and the development of MDS is emerging. Benzene hematotoxicity is mediated via both genotoxic and non-genotoxic mechanisms, leading to aplasia, apoptosis and initiation (via genetic mutation) of clonal disorders such as MDS. Further studies of benzene hematotoxicity and therapy-related MDS should provide models for the elucidation of initiation events in MDS pathogenesis. The importance of such studies is emphasized by the rising frequency of MDS which largely reflects improved diagnostic criteria, increased physician awareness and extended use of diagnostic procedures in the elderly. Demographic changes will lead to a marked increase in MDS over the next few decades.

Animals↗
PubMed1997

Heteroplasmic point mutations of mitochondrial DNA affecting subunit I of cytochrome c oxidase in two patients with acquired idiopathic sideroblastic anemia.

Mitochondrial iron overload in acquired idiopathic sideroblastic anemia (AISA) may be attributable to mutations of mitochondrial DNA (mtDNA), because these can cause respiratory chain dysfunction, thereby impairing reduction of ferric iron (Fe3+) to ferrous iron (Fe2+). The reduced form of iron is essential to the last step of mitochondrial heme biosynthesis. It is not yet understood to which part of the respiratory chain the reduction of ferric iron is linked. In two patients with AISA we identified point mutations of mtDNA affecting the same transmembrane helix within subunit I of cytochrome c oxidase (COX I; ie, complex IV of the respiratory chain). The mutations were detected by restriction fragment length polymorphism analysis and temperature gradient gel electrophoresis. One of the mutations involves a T --> C transition in nucleotide position 6742, causing an amino acid change from methionine to threonine. The other mutation is a T --> C transition at nt 6721, changing isoleucine to threonine. Both amino acids are highly conserved in a wide range of species. Both mutations are heteroplasmic, ie, they establish a mixture of normal and mutated mitochondrial genomes, which is typical of disorders of mtDNA. The mutations were present in bone marrow and whole blood samples, in isolated platelets, and in granulocytes, but appeared to be absent from T and B lymphocytes purified by immunomagnetic bead separation. They were not detected in buccal mucosa cells obtained by mouthwashes and in cultured skin fibroblasts examined in one of the patients. In both patients, this pattern of involvement suggests that the mtDNA mutation occurred in a self-renewing bone marrow stem cell with myeloid determination. Identification of two point mutations with very similar location suggests that cytochrome c oxidase plays an important role in the pathogenesis of AISA. COX may be the physiologic site of iron reduction and transport through the inner mitochondrial membrane.

Aged↗
PubMed1997

International scoring system for evaluating prognosis in myelodysplastic syndromes.

Despite multiple disparate prognostic risk analysis systems for evaluating clinical outcome for patients with myelodysplastic syndrome (MDS), imprecision persists with such analyses. To attempt to improve on these systems, an International MDS Risk Analysis Workshop combined cytogenetic, morphological, and clinical data from seven large previously reported risk-based studies that had generated prognostic systems. A global analysis was performed on these patients, and critical prognostic variables were re-evaluated to generate a consensus prognostic system, particularly using a more refined bone marrow (BM) cytogenetic classification. Univariate analysis indicated that the major variables having an impact on disease outcome for evolution to acute myeloid leukemia were cytogenetic abnormalities, percentage of BM myeloblasts, and number of cytopenias; for survival, in addition to the above, variables also included age and gender. Cytogenetic subgroups of outcome were as follows: "good" outcomes were normal, -Y alone, del(5q) alone, del(20q) alone; "poor" outcomes were complex (ie, > or = 3 abnormalities) or chromosome 7 anomalies; and "intermediate" outcomes were other abnormalities. Multivariate analysis combined these cytogenetic subgroups with percentage of BM blasts and number of cytopenias to generate a prognostic model. Weighting these variables by their statistical power separated patients into distinctive subgroups of risk for 25% of patients to undergo evolution to acute myeloid leukemia, with: low (31% of patients), 9.4 years; intermediate-1 (INT-1; 39%), 3.3 years; INT-2 (22%), 1.1 years; and high (8%), 0.2 year. These features also separated patients into similar distinctive risk groups for median survival: low, 5.7 years; INT-1, 3.5 years; INT-2, 1.2 years; and high, 0.4 year. Stratification for age further improved analysis of survival. Compared with prior risk-based classifications, this International Prognostic Scoring System provides an improved method for evaluating prognosis in MDS. This classification system should prove useful for more precise design and analysis of therapeutic trials in this disease.

Acute Disease↗
PubMed1997

Long-term survival of recipients of allogeneic bone-marrow transplantation after mechanical ventilation.

To evaluate the prognostic significance of mechanical ventilation for outcome of intensive care therapy for pulmonary complications after allogeneic bone marrow transplantation (aBMT) we analysed the clinical course of ten patients requiring intubation and mechanical ventilation after aBMT for pulmonary complications. Ten out of eighty-five patients (12%) undergoing aBMT between 1989 and 1995 required mechanical ventilation for pulmonary complications at our university adult intensive care unit (ICU). Ventilation could be discontinued in four patients after pulmonary function improved. Three of these patients are long-term survivors after two to five years (median 37 months) of follow-up. Significant differences between the two groups of survivors (n = 4 patients) and non-survivors (n = 6 patients) which could have an impact on prognosis exist for graft-versus-host-disease (GvHD), (p < 0.04) and the time between aBMT and intubation (p < 0.05). There were no differences for age (median: 36 and 34 years of age respectively), laboratory values, duration of mechanical ventilation (median: 7 days for both groups) and APACHE-scores. In survivors, mechanical ventilation became necessary because of atelectasis or obstruction by mucositis in two cases, septicemia with concomitant ARDS in one case and bacterial pneumonia in one case. In non-survivors, pulmonary complications were caused by infections. Causes of death were septicemia or septic shock in five cases and GvHD-induced bronchiolitis obliterans in one case. In conclusion patients at risk for fatal outcome after intensive-care therapy for pulmonary complications following aBMT show a higher degree of GvHD, more infectious complications and a later onset of ventilation after aBMT. With an overall longterm-survival of 3 out of 10 patients, mechanical ventilation seems to be live-saving in a selected subset of patients.

Adult↗
PubMed1997

Acquired factor VIII inhibitors in nonhemophilic patients.

Antibodies against factor VIII occur in about 15-35% of hemophilia A patients and induce refractoriness to factor VIII substitution. In most cases, these antibodies are of the IgG class. Strategies to avoid or to treat such inhibitors are controversial. In very rare cases, factor VIII inhibitors also develop in nonhemophilic patients. Although there are anecdotal reports that these antibodies may disappear spontaneously without occurrence of bleeding tendencies, in the majority of patients the clinical course is characterized by severe hemorrhages. From 1980 to 1995, we observed ten nonhemophilic patients with acquired factor VIII inhibitors at our hospital. In most cases, a sudden bleeding tendency was observed shortly after an injury or surgery. Coagulation tests showed a prolonged aPTT and a decreased F VIII level. Other deficiencies of blood-clotting factors and acquired or hereditary von Willebrand's disease were excluded. Therapy with F VIII concentrates did not produce the expected increase. Measurement of F VIII inhibitor levels in Bethesda units/ml (BU/ml) revealed maximal values in the range of 2-128 BU/ml. Immunosuppressive therapy with azathioprine or cyclophosphamide in combination with methylprednisolone led to complete disappearance of the inhibitor, normalization of the coagulation tests, and complete remission of the bleeding tendency in seven treated patients within 6 weeks. Although the clinical course is not predictable and inhibitors may disappear spontaneously, combined therapy with methylprednisolone and azathioprine or cyclophosphamide is recommended for patients with bleeding tendency. In pregnancy, therapy should be started only with methylprednisolone; post-partum, azathioprine should be used additionally if methylprednisolone as a single drug does not lead to complete remission. In emergency situations, therapy with high doses of human factor VIII concentrate may be used. When bleeding does not cease, the additional use of activated prothrombin-complex concentrates or porcine factor VIII is indicated. Possible side effects may include hepatitis and short-lived intravascular thrombin production.

Adult↗
PubMed1997

S-HAM induction chemotherapy with or without GM-CSF in patients with high-risk myelodysplastic syndromes.

Thirty-one adult patients with high-risk myelodysplastic syndromes (MDS) were enrolled in a prospective randomized double-blind placebo-controlled trial evaluating the efficacy of sequential high-dose Ara C/mitoxantrone chemotherapy with or without GM-CSF. GM-CSF or placebo was given subcutaneously once daily at a dose of 250 micrograms/m2 starting 48 h prior to chemotherapy and continued until neutrophil recovery. This design allowed us to investigate the role of GM-CSF as a priming factor for the leukemic clone, as well as its effect on the recovery of normal hematopoiesis. Twenty-eight patients are currently evaluable for response. The patients reached a complete remission (36%), eight patients had persistent MDS (29%), and ten patients died within 6 weeks after the onset of treatment (early death). Infectious complications during cytopenia were the major cause of death (8/10). Median time to complete hematologic recovery (neutrophils > 500/microliter and platelets 20,000/microliter) and time to neutrophil recovery above 1500/microliter was 29 and 35 days, respectively. Median remission duration was 190 days (6.4 months). Analysis of prognostic subgroups showed a low CR rate (25%) and a high early-death rate (44%) in patients > 55 years of age, suggesting that the intensified treatment approach should be limited to younger patients. No data concerning the influence of GM-CSF on response to chemotherapy or duration of neutropenia are presently available.

Adult↗
PubMed1997

Pseudomonas aeruginosa blepharoconjunctivitis during cytoreductive chemotherapy in a woman with acute lymphocytic leukemia.

Patients undergoing chemotherapy regimens for hematologic malignancies are prone to develop unusual and potentially life-threatening infections during periods of leukopenia- induced immunosuppression. We report the case of a woman who received consolidation chemotherapy for acute lymphocytic leukemia and acquired necrotizing Pseudomonas aeruginosa blepharoconjunctivitis of the right eye during a period of mild leukopenia. The infection led to severe orbital and periorbital inflammation, spreading down to the neck. High-dose antibiotic treatment with ceftazidime and tobramycin combined with granulocyte cell-stimulating factor cleared the infection after several days, but plastic surgery was needed to restore normal eye closure.

Adult↗
PubMed1997

Fatal hyperleukocytic syndrome in a patient with chronic myelomonocytic leukemia.

A 53-year-old male patient was admitted to our hospital with painful splenomegaly. He was diagnosed as having chronic myelomonocytic leukemia (CMML) with leukocytosis, monocytosis, increased lysozyme concentrations in serum und urine, and lack of the Philadelphia chromosome. The clinical course of the disease was characterized by rapidly rising leukocyte counts, cutaneous infiltrates, respiratory insufficiency and neurological symptoms. Excessive hyperleukocytosis with a significant increase in monocytic cells led to microcirculatory obstruction, vascular endothelial damage and organ malfunction. This complication could not be prevented by low-dose chemotherapy with cytosine arabinoside. The patient finally died from pulmonary and cerebral hyperleukocytic syndrome.

Fatal Outcome↗
PubMed1997

Increases of sICAM-1 during neutropenic pneumonia in leukemic patients.

Aggressive chemotherapy of leukemia increases the risk of severe infections during treatment-induced myelosuppression. However, the assessment of an infectious origin of neutropenic fever is often difficult. Leukocyte adhesion molecules such as E-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) are involved in early inflammatory response. We studied plasma concentrations of their soluble isoforms during 48 treatment courses with myeloablative chemotherapy in 32 leukemic patients. There were 35 febrile episodes during neutropenia. Pneumonia was clinically and microbiologically documented in 15 cases, six had proven infections but normal chest radiograph, and 14 were classified as fever of unknown origin. Longitudinal studies revealed a sustained increase of sICAM-1 plasma levels associated with pneumonia. Increase of sICAM-1 plasma levels distinguished patients with pneumonia from those with fever not related to pneumonia (positive predictive value 0.87, negative predictive value 0.94). Plasma levels of sICAM-1 were elevated in both, fungal and non-fungal pneumonia. Increases of sICAM-1 paralleled first radiographic evidence of pulmonary infiltrations in most cases. In contrast, no elevation of sVCAM-1 or sE-selectin was documented during febrile events prior to recovery of leukocyte counts.

Adult↗
PubMed1997

Large volume leukapheresis maximizes the progenitor cell yield for allogeneic peripheral blood progenitor donation.

We have investigated the efficiency and safety of large volume leukapheresis (LVL) for the collection of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPCs) from healthy donors. In six apheresis sessions in four healthy individuals on a COBE-BCT Spectra cell separator (median processed volume 3.5 X total blood volume, TBV, range 3.3-4.4 X TBV), harvested cells were collected sequentially into three single bags. The collection bags were changed after processing 33%, 66%, and 100% of the prospective apheresis volume, allowing analysis of PBPCs collected at different periods during one harvest. Mononuclear cells (MNCs), CD34+ cells, CD34+ subsets, and lymphocyte subsets were determined in each bag. Substantially more PBPCs were harvested than were in the circulation before G-CSF administration preceding LVL (median 171%, range 69-267%), reflecting progenitor release during the procedure. In donors 1 and 3, the CD34+ cell yields decreased in the third bag to 53% and 42% of that collected in the first bag, whereas the progenitor cell yields in donors 2 and 4 were stable or rose during the procedure, achieving in the third bag 157% and 105% of the number of CD34+ cells collected in the first bag. Minor changes were found in the subsets of CD34+ cells, lymphocytes, and monocytes collected at different periods during a single harvest. LVL was well tolerated. Reversible thombocytopenia developed in all cases. No late effects attributable to LVL or G-CSF were found in the 4 donors and 16 other healthy individuals who have undergone LVL in our institution. We conclude that LVL is safe and maximizes PBPC yields for allogeneic transplantation.

Adult↗
PubMed1997

Lymphoid myelofibrosis associated with high grade B cell lymphoma of the liver: morphological, cytogenetic, and clinical features.

Severe pancytopenia associated with moderate hepatosplenomegaly, increased serum lactic dehydrogenase (LDH) levels, and hypogammaglobulinemia were found in a young male patient. Bone marrow histology showed extensive fibrosis, hypoplasia of erythro- and granulocytopoiesis, and hyperplasia of megakaryocytopoiesis associated with histiocytic fat cell phagocytosis and infiltration of abnormal lymphocytes, compatible with lymphoid myelofibrosis. Striking chromosomal aberrations indicating karyotype evolution were also demonstrated by cytogenetic analyses (47, XY, +3 / 47, XY, +3, 1p+ / 46, XO, +3, 1p+, -Y). The clinical course was characterized by cyclic febrile episodes accompanied by excessive increase of serum LDH levels and leukocyte counts, and decrease of platelet counts, followed by spontaneous regression. Further diagnostic procedures, including two liver biopsies and computed tomography, did not detect any manifestation of lymphoma. Eventually, the patient developed rapidly progressive, lethal pulmonary aspergillosis. At autopsy, high grade B cell lymphoma of the liver was found. In this case, the lymphoid myelofibrosis seen on bone marrow biopsy may be considered as a manifestation of "discordant" bone marrow histology related to high grade lymphoma. With respect to the cyclic clinical course, a possible role of apoptotic mechanisms in the physiopathology of this disorder is reviewed.

Adult↗