Biomedical subjects

C Rieth

Publications and source records attributed to C Rieth.

7 recordsLinked to original sources

PubMed2000

Long-term remission after intensive chemotherapy in advanced myelodysplastic syndromes is generally associated with restoration of polyclonal haemopoiesis.

The clonality of peripheral blood cells was assessed in eight female patients with myelodysplastic syndrome (MDS) by means of the human androgen receptor gene-based assay (HUMARA). The patients were in complete remission for a median follow-up time of 83 months after intensive chemotherapy. X-chromosome inactivation patterns (XCIPs) indicated polyclonal haemopoiesis in five patients. Two patients had skewed lyonization (i.e. unbalanced XCIPs in both granulocytes and T cells) and one patient presented monoclonal granulocytes together with polyclonal T cells. We conclude that long-term remission in MDS following intensive chemotherapy is usually associated with polyclonal haemopoiesis.

Adult↗

PubMed1999

Factors influencing G-CSF-mediated mobilization of hematopoietic progenitor cells during steady-state hematopoiesis in patients with malignant lymphoma and multiple myeloma.

We retrospectively analyzed factors influencing PBPC mobilization during steady-state hematopoiesis in 52 patients with malignant lymphoma (n=35) or multiple myeloma (n=17) who received 77 cycles of G-CSF (12.5-50 microg G-CSF/kg/day). For 15 of these patients, the first mobilization cycle (12.5 microg G-CSF/kg/day) was followed by a second course with an increased dose of G-CSF (25 or 50 microg/kg/day). Leukapheresis was started on day 4, about 2 h after s.c. G-CSF administration, and repeated on 2-5 consecutive days. CD34+ cells were determined by flow cytometry in each apheresis product and in the peripheral blood prior to G-CSF administration, beginning on day 4. Colony assays were performed on cryopreserved samples prior to autografting. In the 15 patients receiving two mobilization cycles the higher G-CSF dose was associated with higher levels of CD34+ cells, a higher mean yield of CD34+ cells per apheresis (p<0.05), and a higher percentage of successful (>2x10(6) CD34+ cells/kg) collections (p=0.058). Patients with limited previous cytotoxic therapy (n=19, up to six cycles of a standard regimen such as CHOP and/or less than 20% marrow irradiation) who received a daily dose of 12.5 microg G-CSF/kg had higher levels of circulating CD34+ cells, a higher mean yield of CD34+ cells per apheresis (p<0.05), and a higher percentage of successful collections (p<0.05) compared with patients previously treated with more intensive radiochemotherapy (n=15). Ten of 20 patients (50%) who failed during the first cycle were successful during subsequent cycles with escalated doses of G-CSF. Trough levels of circulating CD34+ cells on day 4 were predictive for success or failure to achieve >2x10(6) CD34+ cells/kg, especially in heavily pretreated patients. In conclusion, a daily dose of 12.5 microg G-CSF/kg seems sufficient to mobilize PBPC during steady-state hematopoiesis in the majority of patients who have received limited previous radiochemotherapy. Higher doses of G-CSF, up to 50 microg/kg/day, mobilize more PBPC and should be considered for patients previously treated with intensive radiochemotherapy or those failing to mobilize sufficient numbers of CD34+ cells with lower doses of G-CSF.

Adult↗

PubMed1998

Granulocyte colony-stimulating factor (G-CSF) mediated mobilization of leukemic cells in Philadelphia chromosome positive acute lymphoblastic leukemia expressing myeloid antigens (my+Ph+ALL).

The therapeutic benefit of G-CSF in the treatment of acute lymphoblastic leukemia has been well established. G-CSF has been used to shorten neutropenia induced by conventional dose cytotoxic chemotherapy and allogeneic bone marrow transplantation. Recently autologous peripheral blood progenitor cell transplantation has been explored to treat high-risk ALL. Several in vitro studies suggest that subpopulations of lymphoblasts express G-CSF receptors. Furthermore, enhanced growth of Ph+ ALL cells expressing myeloid antigens stimulated by G-CSF has been demonstrated in vitro. However, the clinical relevance of these findings has been questioned. We report a patient with my+Ph+ALL in whom the administration of G-CSF after high-dose Cytarabin and Mitoxantrone led to a significant mobilization of leukemic cells and contamination of the stem cell harvest during cytologic marrow remission.

Adult↗

PubMed1997

Idarubicin, melphalan and cyclophosphamide: an intensified high-dose regimen for the treatment of myeloma patients.

Following conventional chemotherapy, eight myeloma patients presenting with advanced tumor stages were treated with an intensified high-dose regimen and autologous peripheral blood stem cell transplantation. High-dose chemotherapy consisted of idarubicin 20 mg/m2 on days -13, -12 and -11, melphalan 100 mg/m2 on days -5 and -4 and cyclophosphamide 60 mg/kg (plus mesna 60 mg/kg) on days -3 and -2 (IMC). Seven patients achieved a complete remission or a very good partial remission (reduction of M-component > or =90%). There were no toxic deaths. Severe mucositis and fever of unknown origin were seen in all patients. Reversible supraventricular tachycardias without clinical signs of cardiac failure occurred in five patients. One patient developed a persistent deterioration of cardiac function. We surmise that high-dose chemotherapy with IMC is very effective and well tolerated in myeloma patients.

Adult↗

PubMed1994

Preattentive information processing in schizophrenia.

Preattentive and attentive information processing was investigated in 24 schizophrenic patients and 24 control subjects using a texture discrimination task based on Julesz's texton theory. Texton theory essentially defines a certain limited number of texture elements that can be detected readily and simultaneously without attentional effort irrespective of the size and information content of the rest of the visual field. During the first task, subjects had to detect texton elements (one 'L' among 35 '+'), which were presented on slides for 40 ms and were followed by a mask after different stimulus onset asynchronies (SOA: 200-800 ms). At all SOAs tested schizophrenics reported significantly fewer correct responses compared to the control group. In the second task, subjects had to search for texton (one 'L' among 35 '+') and non-texton elements (one 'L' among 35 'T') in the stimulus displays, whereby response times were measured. Schizophrenics showed significantly slower response times only to texton elements, whereas response times to non-texton elements did not significantly differ from controls. Additionally, schizophrenics made significantly more errors detecting non-texton elements than controls. The results suggest a deficit in processing of visual information in schizophrenic patients, which is confined to preattentive processes and may consist of a slowing of those processes. Schizophrenics may also have difficulty in sustaining their attention during search tasks.

Adult↗

PubMed1994

Texture segmentation and 'pop-out' in infants and children: the effect of test field size.

The ability of infants and children to segment textures based on differences in line orientation and blob size was investigated, using a forced-choice preferential looking method. In the first experiment, a stimulus pair (a homogeneous texture and a texture containing either a group of sixteen elements or a single element of an orthogonal orientation or a larger blob size) was presented on two separate test fields. Preference for the figure defined by differences in blob size was seen already in 2-month-old infants. In contrast, preference for a figure defined by differences in orientation emerged at 9-12 months of age and became adult-like around school age (see also Sireteanu and Rieth, Behavioural Brain Res., 49, 133-139, 1992). Preference for the single discrepant element was always lower than preference for the discrepant group. In the second experiment, segmentation of oriented textures presented on a single, rather than two separate surfaces was tested. A significant preference for the embedded discrepant group, but not for the single discrepant element, was seen already at 3 months of age. These results show that infants as young as 3 months of age are able to detect a boundary defined by differences in line orientation (see also Atkinson and Braddick, Behavioural Brain Res., 49, 123-131, 1992). However, this ability does not appear to lead to the 'pop-out' phenomenon, as seen in adult observers, until much later.

Adolescent↗

PubMed1992

Texture segregation in infants and children.

Segregation of textures based on differences in line orientation and blob size was tested in adults, infants and children, with a forced-choice preferential looking technique. Preference for a figure defined by differences in blob size already occurs in 2-month-old infants. In contrast, preference for a figure differing from the background by the orientation of its elements emerges at the end of the first year of life and becomes adult-like by school age.

Adult↗